Network Working Group I. Heizer Request for Comments: DRAFT P. Leach Category: Informational D. Perry Title: draft-heizer-cifs-v1-spec-01.txt Microsoft June 30, 1996 Common Internet File System Protocol (CIFS/1.0) Status of this Memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or made obsolete by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress". To learn the current status of any Internet-Draft, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Distribution of this document is unlimited. Please send comments to the authors at . Discussion of CIFS is on the mailing list ; subscribe by sending a message to with a body of "subscribe CIFS you@your.company.com". There is a CIFS home page at . Abstract This document describes the CIFS file sharing protocol, version 1.0. Client systems use this protocol to request file and print services from server systems over a network. It is based on the Server Message Block protocol widely in use by personal computers and workstations running a wide variety of operating systems. Heizer, et al expires December 1996 [Page 1] INTERNET-DRAFT CIFS/1.0 June 1996 Table of Contents 1. INTRODUCTION 8 1.1 Summary of features 8 1.1.1 File and printer access 9 1.1.2 File and record locking 9 1.1.3 Safe caching, read-ahead, and write-behind 9 1.1.4 File change notification 9 1.1.5 Protocol version negotiation 9 1.1.6 Extended attributes 9 1.1.7 Distributed replicated virtual volumes 10 1.1.8 Server name resolution via DNS 10 1.1.9 Batched requests 10 2. PROTOCOL OPERATION OVERVIEW 11 2.1 Server Name Determination 11 2.2 Server Name Resolution 11 2.3 Sample Message Flow 12 2.4 Message Format 13 2.5 SMB Protocol Dialect Negotiation 15 2.6 Message Transport 15 2.6.1 Reliable Connection Oriented Transports 16 2.6.2 Connectionless Transports 17 2.7 Opportunistic Locks 21 2.7.1 Exclusive Oplocks 21 2.7.2 Batch Oplocks 23 2.7.3 Level II Oplocks 25 2.8 Security Model 26 2.9 Resource Share/Access Example 27 2.10 Authentication 29 2.10.1 Pre NT LM 0.12 30 2.10.2 NT LM 0.12 30 Heizer, et al expires December 1996 [Page 2] INTERNET-DRAFT CIFS/1.0 June 1996 2.11 Distributed Filesystem (DFS) Support 31 3. SMB MESSAGE FORMATS AND DATA TYPES 32 3.1 SMB Header 32 3.1.1 Flags field 33 3.1.2 Flags2 Field 34 3.1.3 Tid Field 35 3.1.4 Pid Field 36 3.1.5 Mid Field 36 3.1.6 Status Field 36 3.1.7 Timeouts 37 3.1.8 Data Buffer (BUFFER) and String Formats 37 3.2 File Names 38 3.3 Wildcards 38 3.4 DFS Pathnames 39 3.5 Time And Date Encoding 40 3.6 Access Mode Encoding 41 3.7 Open Function Encoding 42 3.8 Open Action Encoding 43 3.9 Device State Encoding 43 3.10 File Attribute Encoding 44 3.11 Batching Requests ("AndX" Messages) 45 3.12 "Transaction" Style Subprotocols 46 3.12.1 SMB_COM_TRANSACTION and SMB_COM_TRANSACTION2 Formats 47 3.12.2 SMB_COM_NT_TRANSACTION Formats 50 3.12.3 Functional Description 55 3.13 Valid SMB Requests by Negotiated Dialect 59 4. SMB REQUESTS 61 4.1 Session Requests 61 4.1.1 NEGOTIATE: Negotiate Protocol 61 4.1.2 SESSION_SETUP_ANDX: Session Setup 68 4.1.3 LOGOFF_ANDX: User Logoff 73 4.1.4 TREE_CONNECT_ANDX: Tree Connect 74 Heizer, et al expires December 1996 [Page 3] INTERNET-DRAFT CIFS/1.0 June 1996 4.1.5 TREE_DISCONNECT: Tree Disconnect 78 4.1.6 TRANS2_QUERY_FS_INFORMATION: Get File System Information 78 4.1.7 ECHO: Ping the Server 82 4.1.8 NT_CANCEL: Cancel request 83 4.2 File Requests 83 4.2.1 NT_CREATE_ANDX: Create or Open File ** 83 4.2.2 NT_TRANSACT_CREATE: Create or Open File with EAs or SD 90 4.2.3 CREATE_TEMPORARY: Create Temporary File 93 4.2.4 READ_ANDX: Read Data 94 4.2.5 READ_RAW: Read Raw 97 4.2.6 WRITE_ANDX: Write Bytes to file or resource 101 4.2.7 WRITE_RAW: Write Raw Bytes 104 4.2.8 LOCKING_ANDX: Lock or Unlock Byte Ranges 108 4.2.9 SEEK: Seek in File 112 4.2.10 FLUSH: Flush File 114 4.2.11 CLOSE: Close File 114 4.2.12 DELETE: Delete File 115 4.2.13 RENAME: Rename File 116 4.2.14 MOVE: Rename File 118 4.2.15 COPY: Copy File 119 4.2.16 TRANS2_QUERY_PATH_INFORMATION: Get File Attributes given Path122 4.2.17 TRANS2_SET_PATH_INFORMATION: Set File Attributes given Path 129 4.2.18 TRANS2_QUERY_FILE_INFORMATION: Get File Attributes Given FID131 4.2.19 TRANS2_SET_FILE_INFORMATION: Set File Attributes Given FID 132 4.3 Directory Requests 133 4.3.1 TRANS2_CREATE_DIRECTORY: Create Directory (optional EAs) 133 4.3.2 DELETE_DIRECTORY: Delete Directory 134 4.3.3 CHECK_DIRECTORY: Check Directory 135 4.3.4 TRANS2_FIND_FIRST2: Search Directory using Wildcards 136 4.3.5 TRANS2_FIND_NEXT2: Resume Directory Search Using Wildcards 144 4.3.6 FIND_CLOSE2: Close Directory Search 145 4.3.7 NT_TRANSACT_NOTIFY_CHANGE: Request Change Notification 146 4.4 DFS Operations 149 4.4.1 TRANS2_GET_DFS_REFERRAL: Retrieve Distributed Filesystem Referral 149 4.4.2 TRANS2_REPORT_DFS_INCONSISTENCY: Inform a server about DFS Error 153 4.5 Print Spooling Operations 154 4.5.1 OPEN_PRINT_FILE: Create Print Spool file 154 4.5.2 GET_PRINT_QUEUE: Get Printer Queue Entries 155 4.6 Miscellaneous Operations 157 4.6.1 NT_TRANSACT_IOCTL 157 4.6.2 NT_TRANSACT_QUERY_SECURITY_DESC 158 4.6.3 NT_TRANSACT_SET_SECURITY_DESC 159 5. OBSOLESCENT SMB REQUESTS 159 Heizer, et al expires December 1996 [Page 4] INTERNET-DRAFT CIFS/1.0 June 1996 5.1 CLOSE_PRINT_FILE: Close and Spool Print Job* 160 5.2 CREATE: Create File* 160 5.3 CREATE_DIRECTORY: Create Directory 162 5.4 CREATE_NEW: Create File* 162 5.5 LOCK_AND_READ: Lock and Read Bytes* 164 5.6 LOCK_BYTE_RANGE: Lock Bytes* 166 5.7 OPEN: Open File* 167 5.8 OPEN_ANDX: Open File* 170 5.9 PROCESS_EXIT: Process Exit* 172 5.10 QUERY_INFORMATION: Get File Attributes 174 5.11 QUERY_INFORMATION2: Get File Information 175 5.12 READ: Read File* 176 5.13 READ_MPX: Read Block Multiplex* 177 5.14 SEARCH: Search Directory using Wildcards* 180 5.15 SET_INFORMATION: Set File Attributes 183 5.16 SET_INFORMATION2: Set File Information 184 5.17 QUERY_INFORMATION_DISK: Get Disk Attributes 185 5.18 TRANS2_OPEN2: Create or Open File with Extended Attributes 186 5.19 TREE_CONNECT: Tree Connect 190 5.20 UNLOCK_BYTE_RANGE: Unlock Bytes* 193 5.21 WRITE: Write Bytes* 193 5.22 WRITE_AND_UNLOCK: Write Bytes and Unlock Range* 195 5.23 WRITE_AND_CLOSE: Write Bytes and Close File* 196 5.24 WRITE_MPX: Write Block Multiplex* 198 5.25 WRITE_PRINT_FILE: Write to Print File* 201 6. SMB SYMBOLIC CONSTANTS 202 Heizer, et al expires December 1996 [Page 5] INTERNET-DRAFT CIFS/1.0 June 1996 6.1 SMB Command Codes 202 6.2 Named Pipe Transaction Protocol Subcommand Codes 205 6.3 SMB_COM_TRANSACTION2 Subcommand codes 205 6.4 SMB_COM_NT_TRANSACTION Subcommand Codes 206 6.5 SMB Protocol Dialect Constants 208 7. ERROR CODES AND CLASSES 210 8. LEGAL NOTICE 216 9. REFERENCES 216 10. SECURITY CONSIDERATIONS 216 10.1 Share level protection 216 10.2 Plaintext Password Authentication 217 10.3 LANMAN 2.1 (and earlier) Challenge/Response 217 10.3.1 Known Plaintext Attacks 217 10.3.2 Small Key Space 217 10.3.3 Chosen Plaintext Attacks 218 10.3.4 Dictionary Attacks 218 10.3.5 Badly Chosen Passwords 218 10.4 NT LM 0.12 Challenge/Response 218 10.5 Other attacks 219 10.5.1 Hijack connections 219 10.5.2 Downgrade attack 219 10.5.3 Spoofing by Counterfeit Servers 219 10.5.4 Storing Passwords Safely 219 11. AUTHOR'S ADDRESSES 220 12. 221 Heizer, et al expires December 1996 [Page 6] INTERNET-DRAFT CIFS/1.0 June 1996 Heizer, et al expires December 1996 [Page 7] INTERNET-DRAFT CIFS/1.0 June 1996 1. Introduction This document describes the file and print sharing protocol for a proposed Common Internet File System (CIFS). CIFS is intended to provide an open cross-platform mechanism for client systems to request file and print services from server systems over a network. It is based on the standard Server Message Block (SMB) protocol widely in use by personal computers and workstations running a wide variety of operating systems. An earlier version of this protocol was documented as part of the X/OPEN (now Open Group) CAE series of standards [7]; this document updates the specification to include the latest shipping versions, and is published to allow the creation of implementations that interoperate with those implementations. Use of the Internet and the World Wide Web has been characterized by read-only access. Existing protocols such as FTP are good solutions for one-way file transfer. However, new read/write interfaces will become increasingly necessary as the Internet becomes more interactive and collaborative. Adoption of a common file sharing protocol having modern semantics such as shared files, byte-range locking, coherent caching, change notification, replicated storage, etc. would provide important benefits to the Internet community. 1.1 Summary of features The protocol supports the following features: o File and printer access o File and record locking o Safe caching, read-ahead, and write-behind o File change notification o Protocol version negotiation o Extended attributes o Distributed replicated virtual volumes o Server name resolution using DNS o Batched requests o Operates over connection-oriented or connection-less transports o Unicode file names Heizer, et al expires December 1996 [Page 8] INTERNET-DRAFT CIFS/1.0 June 1996 1.1.1 File and printer access The protocol supports the usual set of file operations: open, close, read, write, and seek. Opening a printer resources as a file and writing to it causes a print job to be queued. 1.1.2 File and record locking The protocol supports file and record locking, as well as unlocked access to files. Applications that lock files can not be improperly interfered with by applications that do not; once a file or record is locked, non-locking applications are denied access to the file. 1.1.3 Safe caching, read-ahead, and write-behind The protocol supports caching, read-ahead, and write-behind, even for unlocked files, as long as they are safe. All these optimizations are safe as long as only one client is accessing a file; read-caching and read-ahead are safe with many clients accessing a file as long as all are just reading. If many clients are writing a file simultaneously, then none are safe, and all file operations have to go to the server. The protocol notifies all clients accessing a file of changes in the number and access mode of clients accessing the file, so that they can use the most optimized safe access method. 1.1.4 File change notification Applications can register with a server to be notified if and when file or directory contents are modified. They can use this to (for example) know when a display needs to be refreshed, without having to constantly poll the server. 1.1.5 Protocol version negotiation There are several different versions and sub-versions of this protocol; a particular version is referred to as a dialect. When two machines first come into network contact they negotiate the dialect to be used. Different dialects can include both new messages as well as changes to the fields and semantics of existing messages in other dialects. 1.1.6 Extended attributes In addition to many built-in file attributes, such as creation and modification times, non-file system attributes can be added by applications, such as the author's name, content description, etc. Heizer, et al expires December 1996 [Page 9] INTERNET-DRAFT CIFS/1.0 June 1996 1.1.7 Distributed replicated virtual volumes The protocol supports file system subtrees which look like to clients as if they are on a single volume and server, but which actually span multiple volumes and servers. The files and directories of such a subtree can be physically moved to different servers, and their names do not have to change, isolating clients from changes in the server configuration. These subtrees can also be transparently replicated for load sharing and fault tolerance. When a client requests a file, the protocol uses referrals to transparently direct a client to the server that stores it. 1.1.8 Server name resolution via DNS The protocol supports resolving server names using the DNS, permitting access to the file systems of other organizations over the Internet, or hierarchical organization of servers' names within an organization. Earlier versions of the protocol only supported a flat server name space. 1.1.9 Batched requests The protocol supports the batching of multiple requests into a single message, in order to minimize round trip latencies, even when a later request depends on the results of an earlier one. Heizer, et al expires December 1996 [Page 10] INTERNET-DRAFT CIFS/1.0 June 1996 2. Protocol Operation Overview In order to access a file on a server, a client has to: o Parse the full file name to determine the server name, and the relative name within that server. o Resolve the server name to a transport address (this may be cached) o Make a connection to the server (if using a connection-oriented transport and no connection has yet been made) o Exchange SMB messages (see below for an example) This process may be repeated as many times as desired. Once the connection has been idle for a while, it may be torn down. 2.1 Server Name Determination How the client determines the name of the server and the relative name within the server is outside of the scope of this specification. However, just for expository purposes, here are three examples. In the URL "file://fs.megacorp.com/users/fred/stuff.txt", the client could take the part between the leading double slashes and the next slash as the server name and the remainder as the relative name -- in this example "fs.megacorp.com" and "/users/fred/stuff.txt", respectively. In the path name "\\corpserver\public\policy.doc" the client could take the part between the leading double backslashes and the next slash as the server name, and the remainder as the relative name -- in this example, "corpserver" and "\public\policy.doc" respectively. In the path name "x:\policy.doc" the client could use "x" as an index into a table that contains a server name and a file name prefix. If the contents of such a table for "x" were "corpserver" and "\public", then the server name and relative name would be the same as in the previous example. 2.2 Server Name Resolution Once the server name has been determined, then the client needs to resolve that name to a transport address. This specification defines three ways of doing so: using the Domain Name System (DNS) [1,2], NETBIOS name resolution (see RFC 1001 and RFC 1002 [3,4]), or IPX naming (see appendix B). Which method is used is configuration dependent; the default is DNS to encourage interoperability over the Internet. The name Heizer, et al expires December 1996 [Page 11] INTERNET-DRAFT CIFS/1.0 June 1996 resolution mechanism used will place constraints on the form of the server name. In the case of NETBIOS, the server name must be 15 characters or less, and be upper case. The server name can also be specified as the string form an IPv4 address in the usual dotted notation, e.g., "157.33.135.101" In this case, "resolution" consists of converting to the 32 bit IPv4 address. 2.3 Sample Message Flow The following illustrates a typical message exchange sequence for a client connecting to a user level server, opening a file, reading its data, closing the file, and disconnecting from the server. Note: using the SMB request batching mechanism (called the "AndX" mechanism), the second to sixth messages in this sequence can be combined into one, so there are really only three round trips in the sequence, and the last one can be done asynchronously by the client. Heizer, et al expires December 1996 [Page 12] INTERNET-DRAFT CIFS/1.0 June 1996 Client Command Server Response ========================== ========================================= SMB_COM_NEGOTIATE Must be the first message sent by client to the server. Includes a list of SMB dialects supported by the client. Server response indicates which SMB dialect should be used. SMB_COM_SESSION_SETUP_ANDX Transmits the user's name and credentials to the server for verification. Successful server response has Uid field set in SMB header used for subsequent SMBs on behalf of this user. SMB_COM_TREE_CONNECT Transmits the name of the disk share the client wants to access. Successful server response has Tid field set in SMB header used for subsequent SMBs referring to this resource. SMB_COM_OPEN Transmits the name of the file, relative to Tid, the client wants to open. Successful server response includes a file id (Fid) the client should supply for subsequent operations on this file. SMB_COM_READ Client supplies Tid, Fid, file offset, and number of bytes to read. Successful server response includes the requested file data. SMB_COM_CLOSE Client closes the file represented by Tid and Fid. Server responds with success code. SMB_COM_TREE_DISCONNECT Client disconnects from resource represented by Tid. 2.4 Message Format Clients exchange messages with a server to access resources on that server. These messages are called Server Message Blocks (SMBs), and every SMB message has a common format. Multi-byte values are always transmitted least significant byte first. Heizer, et al expires December 1996 [Page 13] INTERNET-DRAFT CIFS/1.0 June 1996 typedef unsigned char UCHAR; // 8 unsigned bits typedef unsigned short USHORT; // 16 unsigned bits typedef unsigned long ULONG; // 32 unsigned bits typedef struct { ULONG LowPart; LONG HighPart; } LARGE_INTEGER; // 64 bits of data typedef struct { ULONG LowTime; LONG HighTime; } TIME; typedef struct { UCHAR Protocol[4]; // Contains 0xFF,'SMB' UCHAR Command; // Command code union { struct { UCHAR ErrorClass; // Error class UCHAR Reserved; // Reserved for future use USHORT Error; // Error code } DosError; ULONG NtStatus; // NT-style 32-bit error code } Status; UCHAR Flags; // Flags USHORT Flags2; // More flags union { USHORT Pad[6]; // Ensure this section is 12 // bytes long struct { USHORT PidHigh; // High part of PID // (NT Create And X) ULONG Unused; // Not used USHORT Sid; // Session ID USHORT SequenceNumber; // Sequence number } Connectionless; // IPX }; USHORT Tid; // Tree identifier USHORT Pid; // Caller's process id USHORT Uid; // Unauthenticated user id USHORT Mid; // multiplex id UCHAR WordCount; // Count of parameter words USHORT ParameterWords[ WordCount ]; // The parameter words USHORT ByteCount; // Count of bytes UCHAR Buffer[ ByteCount ]; // The bytes } SMB_HEADER; All SMBs have identical format up to the PARAMETERWORDS fields. Different SMBs have a different number and interpretation of Heizer, et al expires December 1996 [Page 14] INTERNET-DRAFT CIFS/1.0 June 1996 PARAMETERWORDS and BUFFER. All reserved fields in the SMB header must be zero. All quantities are sent in native Intel format. o COMMAND is the operation code which this SMB is requesting, or responding to. o STATUS.DOSERROR.ERRORCLASS and STATUS.DOSERROR.ERROR are set by the server and combine to give the error code of any failed server operation. If the client is capable of receiving 32 bit error returns, the status is returned in STATUS.NTSTATUS instead. When an error is returned, the server may choose to return only the header portion of the response SMB. o FLAGS and FLAGS2 contain bits which, depending on the negotiated protocol dialect, indicate various client capabilities. o PIDHIGH is used in the NTCREATEANDX request SMB o CONNECTIONLESS. SID, and CONNECTIONLESS.SEQUENCENUMBER are used when the client to server connection is on a datagram oriented protocol such as IPX. o TID identifies the subdirectory, or "tree", on the server which the client is accessing. SMBs which do not reference a particular tree should set TID to 0xFFFF o PID is the caller's process id, and is generated by the client to uniquely identify a process within the client computer. o MID is reserved for multiplexing multiple messages on a single Virtual Circuit (VC). A response message will always contain the same value as the corresponding request message. 2.5 SMB Protocol Dialect Negotiation The first message sent from an SMB client to an SMB server must be one whose COMMAND field is SMB_COM_NEGOTIATE. The format of this client request includes an array of NULL terminated strings indicating the dialects of the SMB protocol which the client supports. The server compares this list against the list of dialects the server supports and returns the index of the chosen dialect in the response message. 2.6 Message Transport Clients and servers can exchange messages over a NETBIOS reliable connection oriented transport, or a connectionless transport. Heizer, et al expires December 1996 [Page 15] INTERNET-DRAFT CIFS/1.0 June 1996 2.6.1 Reliable Connection Oriented Transports When using a reliable connection oriented transport, the SMB protocol makes no higher level attempts to ensure sequenced delivery of messages between the client and server. The transport must have some mechanism to detect failures of either the client or server node, and to deliver such an indication to the client or server software so they can clean up state. When a reliable transport connection from a client terminates, all work in progress by that client is terminated by the server and all resources open by that client on the server are closed. 2.6.1.1 Connection Establishment How the connection gets established depends on how the server name was resolved to the transport address: with DNS, with an explicit IP address, or with NETBIOS. 2.6.1.1.1 DNS When using DNS, the server name is mapped onto an IP address and the connection is established by using the session establishment protocol as outlined in RFC 1001 and RFC 1002. The client should initiate the session setup using a called name which is obtained by taking the first component of the server name, converting it to upper case, and padding it up to a length of 16 with banks (hex 20 value). 2.6.1.1.2 Explicit IP Address The connection is established by using the session establishment protocol as outlined in RFC 1001 and RFC 1002; the client should use "*SMBSERVER " as the called name in the session establishment protocol (since it does not know the server name). 2.6.1.1.3 NETBIOS When using NETBIOS name resolution, the NETBIOS session establishment protocol as outlined in RFC 1001 and RFC 1002 must also be used. The NETBIOS name used for session establishment is the server name converted to upper case and padded to a length of 16 with blanks (hex 20 value). Server-side Connection Procedures The server should register a listen on at least one of the following names on the network using the NETBIOS name registration services. If the server wishes to support clients that use NETBIOS name resolution, it registers a 16 character name that is obtained by padding the server machine name with additional blanks if required. If the server wishes to support clients that use DNS name resolution, the name to register is obtained by taking the first component of the server name and padding it up to a length of 16 with blanks, and the 16th character of the name must be a blank (20 hex). Note: while the local server name and the Heizer, et al expires December 1996 [Page 16] INTERNET-DRAFT CIFS/1.0 June 1996 registered DNS server name may differ, it usually makes administration easier to have them the same. If servers wish to allow access via explicit IP address, they should register the name "*SMBSERVER " (padded to 16 characters with blanks) as a local name in NETBIOS. This name must not be defended on the network. 2.6.1.2 Connection Management Once a connection is established, the rules for reliable transport connection dissolution are: o If a server receives a transport establishment request from a client with which it is already conversing, the server may terminate all other transport connections to that client. This is to recover from the situation where the client was suddenly rebooted and was unable to cleanly terminate its resource sharing activities with the server. o A server may drop the transport connection to a client at any time if the client is generating malformed or illogical requests. However, wherever possible the server should first return an error code to the client indicating the cause of the abort. o If a server gets a hard error on the transport (such as a send failure) the transport connection to that client may be aborted. o A server may terminate the transport connection when the client has no open resources on the server, however, we recommend that the termination be performed only after some time has passed or if resources are scarce on the server. This will help performance in that the transport connection will not need to be reestablished if activity soon begins anew. Client software is expected to be able to automatically reconnect to the server if this happens.. 2.6.2 Connectionless Transports The SMB protocol can be run over connectionless transports such as IPX and UDP/IP. Since connectionless transports do not support reliable delivery, this has to be implemented in the SMB protocol itself when utilizing such transports. Unlike a traditional transport protocol, the connectionless SMB protocol is asymmetric. Wherever possible, processing overhead has been moved from the server to the client so that the server can scale to a large number of clients efficiently. For example, the server does not initiate retransmission of lost responses. It is entirely up to the client to resend the request in the case of lost packets in either direction. Heizer, et al expires December 1996 [Page 17] INTERNET-DRAFT CIFS/1.0 June 1996 The SMB header includes two fields specifically designed for use on connectionless transports. "Sid" is the server's session ID and "SequenceNumber" is the message sequence number. The Sid value is generated by the server, and returned to the client in the NegotiateProtocol response. The client must use this Sid value in all future SMB exchanges with this server during this resource sharing session. SequenceNumber is supplied by the client. A valid SequenceNumber is either zero or one greater than the previous sequence number sent by the client. For sequenced commands, the server requires that the sequence numbers progress in order, S, S+1, S+2, ... The sequence number wraps to one (1) not zero. The wrap around progression is: 65534, 65535, 1, 2, ... Out of sequence commands are ignored by the server. For unsequenced commands (i.e. SequenceNumber is 0) the redirector must use the Mid field to identify SMB responses. The redirector should take steps to generate relatively unique values for Mid for each request. In particular, the client must ensure that it never has two or more distinct requests outstanding to the server whose SequenceNumbers are 0 and whose Mids are identical. The client must limit the negotiated buffer size to the maximum MTU of the connectionless transport. If desired, the client could dynamically determine the maximum packet size by sending echo SMBs to the server using various packet sizes and then selecting the largest size which worked correctly. For SMB operation over connectionless transports, commands are divided into two classes: sequenced commands and unsequenced commands. Sequenced commands are used for operations which cause a state change on the server that cannot be repeated, and which have relatively few bytes in the response. For example, file open/close or record locking. Unsequenced commands are used for operations which can be performed as many times as necessary with the same result each time or which have multi-packet responses. For example, reading or writing to a disk file. The client should must send all commands with a large response size as unsequenced; such commands include file read and file search. 2.6.2.1 Errors specific to connectionless transport operation If the response to a sequenced command is too large, the server will fail the request with a Status.DosError.ErrorClass set to SMB_ERR_CLASS_SERVER and Status.DosError.Error set to ERRerror. If the Sid value is incorrect, the server will fail the request with a Status.DosError.ErrorClass set to SMB_ERR_CLASS_SERVER and Status.DosError.Error set to SMB_ERR_BAD_SID. If the server has an SMB in progress which matches either SequenceNumber for sequenced commands or Mid for unsequenced commands, it will respond with Status.DosError.ErrorClass set to SMB_ERR_CLASS_SERVER and Status.DosError.Error set to SMB_ERR_WORKING. Heizer, et al expires December 1996 [Page 18] INTERNET-DRAFT CIFS/1.0 June 1996 2.6.2.2 Transaction SMBs The exceptions to the "large response requires unsequenced" rule are transaction SMBs. These SMBs are used both to retrieve bulk data from the server (EG: enumerate shares, etc.) and to change the server's state (EG: add a new share, change file permissions, etc.) Transaction requests are also unusual because they can have a multiple part request and/or a multiple part response. For this reason, transactions are handled as a set of sequenced commands to the server. Each part of a request is sent as a sequenced command using the same Mid value and an increasing Seq value. The server responds to each request piece except the last one with a response indicating that the server is ready for the next piece. The last piece is responded to with the first piece of the result data. The client then sends a transaction secondary SMB with ParameterDisplacement set to the number of parameter bytes received so far and DataDisplacement set to the number of data bytes received so far and ParameterCount, ParameterOffset, DataCount, and DataOffset set to zero (0). The server responds with the next piece of the transaction result. The process is repeated until all of the response information has been received. When the transaction has been completed, the redirector must send another sequenced command (an echo SMB will do fine) to the server to allow the server to know that the final piece was received and that resources allocated to the transaction command may be released. The flow is as follows, where (S) is the SequenceNumber, (N) is the number of request packets to be sent from the client to the server, and (M) is the number of response packets to be sent by the server to the client: Heizer, et al expires December 1996 [Page 19] INTERNET-DRAFT CIFS/1.0 June 1996 Client <-> Server ======================= === =========================== SMB(S) Transact -> <- OK (S) send more data [ repeat N-1 times: SMB(S+1) Transact -> secondary <- OK (S+1) send more data SMB(S+N-1) ] <- OK (S+N-1) transaction response (1) [ repeat M-1 times: SMB(S+N) Transact -> secondary <- OK (S+N) transaction response (2) SMB(S+N+M-2) Transact -> secondary <- OK (S+N+M-2] transaction response (M) ] SMB(S+N+M-1) Echo -> <- OK (S+N+M-1) echoed In order to allow the server to detect clients which have been powered off, have crashed, etc., the client must send commands to the server periodically if it has resources open on the server. If nothing has been received from a client for awhile, the server will assume that the client is no longer running and disconnect the client. This includes closing any files that the client had open at the time and releasing any Heizer, et al expires December 1996 [Page 20] INTERNET-DRAFT CIFS/1.0 June 1996 resources being used on behalf of the client. Clients should at least send an echo SMB to the server every four (4) minutes if there is nothing else to send. The server will disconnect clients after a configurable amount of time which cannot be less than five (5) minutes. (Note: the NT server has a default timeout value of 15 minutes.) 2.7 Opportunistic Locks Network performance can be increased if the client can locally buffer file data. For example, the client does not have to write information into a file on the server if the client knows that no other process is accessing the data. Likewise, the client can buffer read-ahead data from the file if the client knows that no other process is writing the data. The mechanism which allows clients to dynamically alter their buffering strategy in a consistent manner is knows as "opportunistic locks", or OPLOCKS for short. Versions of the SMB file sharing protocol including and newer than the LANMAN1.0 dialect support oplocks. There are three different types of oplocks: o An EXCLUSIVE oplock allows a client to open a file for exclusive access and allows the client to perform arbitrary buffering o A BATCH oplock allows a client to keep a file open on the server even though the local accessor on the client machine has closed the file. o A LEVEL II oplock indicates there are multiple readers of a file, and no writers. Level II oplocks are supported if the negotiated dialect is NT LM 0.12 or later. When a client opens a file, it requests the server to grant it a particular type of oplock on the file. The response from the server indicates the type of oplock granted to the client. The client uses the granted oplock type to adjust its buffering policy. The SMB_COM_LOCKING_ANDX SMB is used to convey oplock break and response information. Oplocks are not supported over connectionless transports. 2.7.1 Exclusive Oplocks If a client is granted an exclusive oplock, it may buffer lock information, read-ahead data, and write data on the client because the client knows that it is the only accessor to the file. The basic protocol is that the redirector on the client opens the file requesting that an oplock be given to the client. If the file is open by anyone else, then the client is refused the oplock and no local buffering may Heizer, et al expires December 1996 [Page 21] INTERNET-DRAFT CIFS/1.0 June 1996 be performed on the local client. This also means that no readahead may be performed to the file, unless the redirector knows that it has the read ahead range locked. If the server grants the exclusive oplock, the client can perform certain optimizations for the file such as buffering lock, read, and write data. The exclusive oplock protocol is: Client <-> Server A B ============== =========== === ================================ Open ("foo") -> <- Open OK. Exclusive oplock granted. Open("foo") -> <- oplock break to A lock(s) -> <- lock(s) response(s) write(s) -> <- write(s) response(s) close or done -> <- open response to B As can be seen, when client A opens the file, it can request an exclusive oplock. Provided no one else has the file open on the server, then the oplock is granted to client A. If, at some point in the future, another client, such as client B, requests an open to the same file, then the server must have client A break its oplock. Breaking the oplock involves client A sending the server any lock or write data that it has buffered, and then letting the server know that it has acknowledged that the oplock has been broken. This synchronization message informs the server that it is now permissible to allow client B to complete its open. Heizer, et al expires December 1996 [Page 22] INTERNET-DRAFT CIFS/1.0 June 1996 Client A must also purge any readahead buffers that it has for the file. This is not shown in the above diagram since no network traffic is needed to do this. 2.7.2 Batch Oplocks Batch oplocks are used where common programs on a client behave in such a way that causes the amount of network traffic on a wire to go beyond an acceptable level for the functionality provided by the program. For example, the command processor executes commands from within a command procedure by performing the following steps: o Opening the command procedure. o Seeking to the "next" line in the file. o Reading the line from the file. o Closing the file. o Executing the command. This process is repeated for each command executed from the command procedure file. As is obvious, this type of programming model causes an inordinate amount of processing of files, thereby creating a lot of network traffic that could otherwise be curtailed if the program were to simply open the file, read a line, execute the command, and then read the next line. Batch oplocking curtails the amount of network traffic by allowing the client to skip the extraneous open and close requests. When the command processor then asks for the next line in the file, the client can either ask for the next line from the server, or it may have already read the data from the file as readahead data. In either case, the amount of network traffic from the client is greatly reduced. If the server receives either a rename or a delete request for the file that has a batch oplock, it must inform the client that the oplock is to be broken. The client can then change to a mode where the file is repeatedly opened and closed. The batch oplock protocol is: Heizer, et al expires December 1996 [Page 23] INTERNET-DRAFT CIFS/1.0 June 1996 Client <-> Server A B =========== ============ ==== =============================== Open("foo") -> <- Open OK. Batch oplock granted. Read -> <- data -> read <- data Open("foo") -> <- Oplock break to A Close -> <- Close OK to A <- Open OK to B When client A opens the file, it can request an oplock. Provided no one else has the file open on the server, then the oplock is granted to client A. Client A, in this case, keeps the file open for its caller across multiple open/close operations. Data may be read ahead for the caller and other optimizations, such as buffering locks, can also be performed. When another client requests an open, rename, or delete operation to the server for the file, however, client A must cleanup its buffered data and synchronize with the server. Most of the time this involves actually closing the file, provided that client A's caller actually Heizer, et al expires December 1996 [Page 24] INTERNET-DRAFT CIFS/1.0 June 1996 believes that he has closed the file. Once the file is actually closed, client B's open request can be completed. 2.7.3 Level II Oplocks Level II oplocks allow multiple clients to have the same file open, providing that no client is performing write operations to the file. This is important for many environments because most compatibility mode opens from down-level clients map to an open request for shared read/write access to the file. While it makes sense to do this, it also tends to break oplocks for other clients even though neither client actually intends to write to the file. The Level II oplock protocol is: Client <-> Server A B =========== =========== ==== ==================================== Open("foo") -> <- Open OK. Exclusive oplock granted. Read -> <- data Open("foo") -> <- Break to Level II oplock to A lock(s) -> <- lock(s) response(s) done -> <- Open OK. Oplock II oplock granted to B This sequence of events is very much like an exclusive oplock. The basic difference is that the server informs the client that it should break to a level II lock when no one has been writing the file. That is, client A, for example, may have opened the file for a desired access Heizer, et al expires December 1996 [Page 25] INTERNET-DRAFT CIFS/1.0 June 1996 of READ, and a share access of READ/WRITE. This means, by definition, that client A will not performed any writes to the file. When client B opens the file, the server must synchronize with client A in case client A has any buffered locks. Once it is synchronized, client B's open request may be completed. Client B, however, is informed that he has a level II oplock, rather than an exclusive oplock to the file. In this case, no client that has the file open with a level II oplock may buffer any lock information on the local client machine. This allows the server to guarantee that if any write operation is performed, it need only notify the level II clients that the lock should be broken without having to synchronize all of the accessors of the file. The level II oplock may be BROKEN TO NONE, meaning that some client that had the file opened has now performed a write operation to the file. Because no level II client may buffer lock information, the server is in a consistent state. The writing client, for example, could not have written to a locked range, by definition. Read ahead data may be buffered in the client machines, however, thereby cutting down on the amount of network traffic required to the file. Once the level II oplock is broken, however, the buffering client must flush its buffers and degrade to performing all operations on the file across the network. No oplock break response is expected from a client when the server breaks a client from LEVEL II to NONE. 2.8 Security Model Each server makes a set of resources available to clients on the network. A resource being shared may be a directory tree, named pipe, printer, etc. So far as clients are concerned, the server has no storage or service dependencies on any other servers; a client considers the server to be the sole provider of the file (or other resource) being accessed. The SMB protocol requires server authentication of users before file accesses are allowed, and each server authenticates its own users. A client system must send authentication information to the server before the server will allow access to its resources. The SMB protocol defines two methods which can be selected by the server for security: share level and user level: o A share level server makes some directory on a disk device (or other resource) available. An optional password may be required to gain access. Thus any user on the network who knows the name of the server, the name of the resource and the password has access to the resource. Share level security servers may use different passwords for the same shared resource with different passwords allowing different levels of access. Heizer, et al expires December 1996 [Page 26] INTERNET-DRAFT CIFS/1.0 June 1996 o A user level server makes some directory on a disk device (or other resource) available but in addition requires the client to provide a user name and corresponding user password to gain access. User level servers are preferred over share level servers for any new server implementation, since organizations generally find user level servers easier to administer as employees come and go. User level servers may use the account name to check access control lists on individual files, or may have one access control list that applies to all files in the directory. When a user level server validates the account name and password presented by the client, an identifier representing that authenticated instance of the user is returned to the client in the Uid field of the response SMB. This Uid must be included in all further requests made on behalf of the user from that client. A share level server returns no useful information in the Uid field. The user level security model was added after the original dialect of the SMB protocol was issued, and subsequently some clients may not be capable of sending account name and passwords to the server. A server in user level security mode communicating with one of these clients will allow a client to connect to resources even if the client has not sent account name and password information: 1. If the client's computer name is identical to an account-name known on the server, and if the password supplied to connect to the shared resource matches that account's password, an implicit "user logon" will be performed using those values. If the above fails, the server may fail the request or assign a default account name of its choice. 2. The value of Uid in subsequent requests by the client will be ignored and all access will be validated assuming the account name selected above. 2.9 Resource Share/Access Example The following examples illustrate a possible command line user interface for a server to offer a disk resource, and for a client to connect to and use that resource. a) NET SHARE The NET SHARE command, when executed on the server, specifies a directory name to be made available to clients on the network. A share name must be given, and this name is presented by clients wishing to access the directory. Heizer, et al expires December 1996 [Page 27] INTERNET-DRAFT CIFS/1.0 June 1996 Examples: NET SHARE src=c:\dir1\src "bonzo" assigns password BONZO to all files within directory C:\DIR1\SRC and its subdirectories with the share name SRC being the name used to connect to this resource. NET SHARE c=c:\ " " RO NET SHARE work=c:\work "flipper" RW offers read-only access to everything on the C drive. Offers read- write access to all files within the C:\WORK directory and its subdirectories. The above example is appropriate for servers operating as a SHARE LEVEL server. A USER LEVEL server would not require the permissions or password, since the combination of the client's account name and specific access control lists on files is sufficient to govern access. b) NET USE Clients can gain access to one or more offered directories via the NET USE command. Once the NET USE command is issued the user can access the files freely without further special requirements. Examples: 1. NET USE d: \\Server1\src "bonzo" gains full access to the files and directories on Server1 matching the offer defined by the netname SRC with the password of BONZO. The user may now address files on SERVER1 C:\DIR1\SRC by referencing d:. E.g. "type d:srcfile1.c". 2. NET USE e: \\Server1\c 3. NET USE f: \\Server1\work "flipper" Now any read request to any file on that node (drive c) is valid (e.g. "type e:\bin\foo.bat"). Read-write requests only succeed to files whose pathnames start with f: (e.g. "copy foo f:foo.tmp" copies foo to Server1 c:\work\foo.tmp). For USER LEVEL servers, the client would not provide a password with the NET USE command. The client software must remember the drive identifier supplied with the NET USE request and associate it with the TID value returned by the server in the SMB header. Subsequent requests using this TID must include only the pathname relative to the connected subtree as the Heizer, et al expires December 1996 [Page 28] INTERNET-DRAFT CIFS/1.0 June 1996 server treats the subtree as the root directory (virtual root). When the user references one of the remote drives, the client software looks through its list of drives for that node and includes the tree id associated with this drive in the TID field of each request. Note that one shares a directory and all files underneath that directory are then affected. If a particular file is within the range of multiple shares, connecting to any of the share ranges gains access to the file with the permissions specified for the offer named in the NET USE. The server will not check for nested directories with more restrictive permissions. 2.10 Authentication An SMB server keeps an encrypted form of a client's password. To gain authenticated access to server resources, the server sends a challenge to the client, which the client responds to in a way that proves it knows the client's password. Authentication makes use of DES encryption [5] in block mode. We denote the DES encryption function as E(K,D), which accepts a seven byte key (K) and an eight byte data block (D) and produces an eight byte encrypted data block as its value. If the data to be encrypted is longer than eight bytes, the encryption function is applied to each block of eight bytes in sequence and the results are appended together. If the key is longer than seven bytes, the data is first completely encrypted using the first seven bytes of the key, then the second seven bytes, etc., appending the results each time. In other words, to encrypt the 16 byte quantity D0D1 with the 14 byte key K0K1, E(K0K1,D0D1) = E(K0,D0)E(K0,D1)E(K1,D0)E(K1,D1) The EncryptionKey field in the SMB_COM_NEGPROT response contains an 8 byte challenge denoted below as "C8", chosen to be unique to prevent replay attacks; the client responds with a 24 byte response denoted "P24", and computed as described below. (Note: the name "EncryptionKey" is historical -- it doesn't actually hold an encryption key.) Clients send the response to the challenge in the SMB_COM_TREE_CONNECT, SMB_COM_TREE_CONNECT_ANDX, and/or SMB_COM_SESSION_SETUP_ANDX request which follows the SMB_COM_NEGPROT message exchange. The server must validate the response by performing the same computations the client did to create it, and ensuring the strings match. If the comparisons fail, the client system may be incapable of encryption; if so the string may be the user password in clear text. The server should try to validating the string as though it were the unencrypted password. The SMB field used to store the response depends upon the request: Heizer, et al expires December 1996 [Page 29] INTERNET-DRAFT CIFS/1.0 June 1996 o Password in SMB_COM_TREE_CONNECT o Password in SMB_COM_TREE_CONNECT_ANDX o AccountPassword in SMB_COM_SESSION_SETUP_ANDX (Note: again, the names are historical, and do not reflect this usage.) The contents of the response to the challenge depends on the SMB dialect, as outlined in the following sections: 2.10.1 Pre NT LM 0.12 o The client and server both compute P16 = E(P14,S8) and P24 = E(P21,C8) where: o P14 is a 14 byte string containing the user's password in clear text, upper cased, padded with spaces o S8 is an eight byte string whose value is available from Microsoft upon request. o P21 is a twenty one byte string obtained by appending five null bytes to the string P16, just computed o C8 is the value of the challenge sent in the EncryptionKey field in the SMB_COM_NEGPROT response for this connection. 2.10.2 NT LM 0.12 The client and server both compute P16 = MD4(U(PN)) and P24 = E(P21, C8) where: o PN is a string containing the user's password in clear text, case sensitive, no maximum length Heizer, et al expires December 1996 [Page 30] INTERNET-DRAFT CIFS/1.0 June 1996 o U(x) of an ASCII string "x" is that string converted to Unicode o MD4(x) of an octet string "x" is the 16 byte MD4 message digest [6] of that string o P21 and C8 are as above. 2.11 Distributed Filesystem (DFS) Support Protocol dialects of NT LM 0.12 and later support distributed filesystem operations. The distributed filesystem gives a way for this protocol to use a single consistent file naming scheme which may span a collection of different servers and shares. The distributed filesystem model employed is a referral - based model. This protocol specifies the manner in which clients receive referrals. The client can set a flag in the request SMB header indicating that the client wants the server to resolve this SMB's paths within the DFS known to the server. The server attempts to resolve the requested name to a file contained within the local directory tree indicated by the TID of the request and proceeds normally. If the request pathname resolves to a file on a different system, the server returns the following error: STATUS_DFS_PATH_NOT_COVERED - the server does not support the part of the DFS namespace needed to resolved the pathname in the request. The client should request a referral from this server for further information. A client asks for a referral with the TRANS2_DFS_GET_REFERRAL request containing the DFS pathname of interest. The response from the server indicates how the client should proceed. The method by which the topological knowledge of the DFS is stored and maintained by the servers is not specified by this protocol. Heizer, et al expires December 1996 [Page 31] INTERNET-DRAFT CIFS/1.0 June 1996 3. SMB Message Formats and Data Types This section describes the entire set of SMB commands and responses exchanged between SMB clients and servers. It also details which SMBs are introduced into the protocol as higher dialect levels are negotiated. 3.1 SMB Header While each SMB command has specific encodings, there are some fields in the SMB header which have meaning to all SMBs. These fields and considerations are described in the following sections. Heizer, et al expires December 1996 [Page 32] INTERNET-DRAFT CIFS/1.0 June 1996 3.1.1 Flags field This field contains 8 individual flags, numbered from least significant to most significant, and have the following meanings: Bit Meaning Earliest Dialect === ================================================ ============ 0 When set (returned) from the server in the LANMAN1.0 SMB_COM_NEGOTIATE response SMB, this bit indicates that the server supports the "sub dialect" consisting of the LockandRead and WriteandUnlock protocols defined later in this document. 1 When on (on an SMB request being sent to the server), the client guarantees that there is a receive buffer posted such that a send without acknowledgment can be used by the server to respond to the client's request. 2 Reserved (must be zero). 3 When on, all pathnames in this SMB must be LANMAN1.0 treated as caseless. When off, the pathnames are case sensitive. 4 When on (in SMB_COM_SESSION_SETUP_ANDX defined LANMAN1.0 later in this document), all paths sent to the server by the client are already canonicalized. This means that file/directory names are in upper case, are valid characters, . and .. have been removed, and single backslashes are used as separators. 5 When on (in SMB_COM_OPEN, SMB_COM_CREATE and LANMAN1.0 SMB_COM_CREATE_NEW), this indicates that the client is requesting that the file be "opportunistically" locked if this process is the only process which has the file open at the time of the open request. If the server "grants" this oplock request, then this bit should remain set in the corresponding response SMB to indicate to the client that the oplock request was granted. See the discussion of "oplock" in the sections defining the SMB_COM_OPEN_ANDX and SMB_COM_LOCKING_ANDX protocols later in this document (this bit has the same function as bit 1 of Flags if the Heizer, et al expires December 1996 [Page 33] INTERNET-DRAFT CIFS/1.0 June 1996 SMB_COM_OPEN_ANDX SMB). 6 When on (in core protocols SMB_COM_OPEN_ANDX, LANMAN1.0 SMB_COM_CREATE and SMB_COM_CREATE_NEW), this indicates that the server should notify the client on any action which can modify the file (delete, setattrib, rename, etc.) by another client. If not set, the server need only notify the client about another open request by a different client. See the discussion of "oplock" in the sections defining the SMB_COM_OPEN_ANDX and SMB_COM_LOCKING_ANDX SMBs later in this document (this bit has the same function as bit 2 of smb_flags of the SMB_COM_OPEN_ANDX SMB). Bit6 only has meaning if bit5 is set.. 7 When on, this SMB is being sent from the server PC NETWORK in response to a client request. The Command PROGRAM 1.0 field usually contains the same value in a protocol request from the client to the server as in the matching response from the server to the client. This bit unambiguously distinguishes the command request from the command response. 3.1.2 Flags2 Field This field contains six individual flags, numbered from least significant bit to most significant bit, which are defined below. Flags which not defined must be set to zero. Bit Meaning Earliest Dialect === =============================================== ============ 0 If set, the client knows how to handle names which do not conform to the MS-DOS 8.3 naming convention. 1 If set, the client is aware of extended attributes 2 If set, SMB_FLAGS2_IS_LONG_NAME 12 If set, any request pathnames in this SMB NT LM 0.12 should be resolved in the Distributed File Heizer, et al expires December 1996 [Page 34] INTERNET-DRAFT CIFS/1.0 June 1996 System 13 If set, indicates that a read will be permitted if the client does not have read permission but does have execute permission. This flag is only useful on a read request. 14 If set, specifies that the returned error code is a 32 bit error code in Status.NtStatus. Otherwise the Status.DosError.ErrorClass and Status.DosError.Error fields contain the DOS- style error information. When passing NT status codes is negotiated, this flag should be NT LM 0.12 set for every SMB. 15 If set, any strings in this SMB message are NT LM 0.12 encoded as UNICODE. Otherwise, all strings are in ASCII. 3.1.3 Tid Field TID represents an instance of an authenticated connection to a server resource. TID is returned by the server to the client when the client successfully connects to a resource, and the client uses TID in subsequent requests referring to the resource. If the server is executing in a SHARE LEVEL security mode, TID is the only thing used to allow access to the shared resource. Thus if the user is able to perform a successful connection to the server specifying the appropriate netname and passwd (if any) the resource may be accessed according to the access rights associated with the shared resource (same for all who gained access this way). If however the server is executing in USER LEVEL security mode, access to the resource is based on the UID (validated on the SMB_COM_SESSION_SETUP_ANDX request) and the TID is NOT associated with access control but rather merely defines the resource (such as the shared directory tree). In most SMB requests, TID must contain a valid value. Exceptions include prior to getting a TID established including SMB_COM_NEGOTIATE, SMB_COM_TREE_CONNECT, SMB_COM_ECHO, and SMB_COM_SESSION_SETUP_ANDX. 0xFFFF should be used for Tid for these situations. The server is always responsible for enforcing use of a valid TID where appropriate. Heizer, et al expires December 1996 [Page 35] INTERNET-DRAFT CIFS/1.0 June 1996 3.1.4 Pid Field PID uniquely identifies a client process. Clients inform servers of the creation of a new process by simply introducing a new PID value into the dialogue for new processes. In the core protocol, the SMB_COM_PROCESS_EXIT SMB was used to indicate the catastrophic termination of a process on the client. In the single tasking DOS system, it was possible for hard errors to occur causing the destruction of the process with files remaining open. Thus a SMB_COM_PROCESS_EXIT SMB was sent for this occurrence to allow the server to close all files opened by that process. In the LANMAN 1.0 and newer dialects, no SMB_COM_PROCESS_EXIT SMB is sent. The client operating system must ensure that the appropriate close and cleanup SMBs will be sent when the last process referencing the file closes it. From the server's point of view, there is no concept of FIDs "belonging to" processes. A FID returned by the server to one process may be used by any other process using the same transport connection and TID. There is no process creation SMB sent to the server; it is up to the client to ensure only valid client processes gain access to FIDs (and TIDs). On SMB_COM_TREE_DISCONNECT (or when the client and server session is terminated) the server will invalidate any files opened by any process on that client. 3.1.5 Mid Field Clients using the LANMAN 1.0 and newer dialects will typically be multitasked and allow multiple asynchronous input/output requests per task. Therefore a multiplex ID (MID) is used along with PID to allow multiplexing the single client and server connection among the client's multiple processes, threads, and requests per thread. Regardless of negotiated dialect, the server is responsible for ensuring that every response contains the same MID and PID values as its request. The client may then use the MID and PID values for associating requests and responses and may have up to the negotiated number of requests outstanding at any time to a particular server. 3.1.6 Status Field An SMB returns error information to the client in the STATUS field. Protocol dialects prior to NT LM 0.12 return status to the client using the combination of STATUS.DOSERROR.ERRORCLASS and STATUS.DOSERROR.ERROR. Beginning with NT LM 0.12 SMB servers can return 32 bit error information to clients using STATUS.NTSTATUS if the incoming client SMB has bit 14 set in the FLAGS2 field of the SMB header. Any valid NT status code may be returned in this case. The contents of response parameters is not guaranteed in the case of an error return, and must be ignored. For write behind activity, a subsequent write or close of the Heizer, et al expires December 1996 [Page 36] INTERNET-DRAFT CIFS/1.0 June 1996 file may return the fact that a previous write failed. Normally write behind failures are limited to hard disk errors and device out of space. 3.1.7 Timeouts In general, SMBs are not expected to block at the server; they should return "immediately". But some SMB requests do indicate timeout periods for the completion of the request on the server. If a server implementation can not support timeouts, then an error can be returned just as if a timeout had occurred if the resource is not available immediately upon request. 3.1.8 Data Buffer (BUFFER) and String Formats The data portion of SMBs typically contains the data to be read or written, file paths, or directory paths. The format of the data portion depends on the message. All fields in the data portion have the same format. In every case it consists of an identifier byte followed by the data. Identifier Description Value =============== ========================= ===== Data Block See Below 1 Dialect Null terminated String 2 Pathname Null terminated String 3 ASCII Null terminated String 4 Variable block See Below 5 When the identifier indicates a data block or variable block then the format is a word indicating the length followed by the data. In all dialects prior to NT LM 0.12, all strings are encoded in ASCII. If the agreed dialect is NT LM 0.12 or later, Unicode strings may be exchanged. Unicode strings include file names, resource names, and user names. This applies to null-terminated strings, length specified strings and the type-prefixed strings. In all cases where a string is passed in Unicode format, the Unicode string must be word-aligned with respect to the beginning of the SMB. Should the string not naturally fall on a two-byte boundary, a null byte of padding will be inserted, Heizer, et al expires December 1996 [Page 37] INTERNET-DRAFT CIFS/1.0 June 1996 and the Unicode string will begin at the next address. In the description of the SMBs, items that may be encoded in Unicode or ASCII are labeled as STRING. If the encoding is ASCII, even if the negotiated string is Unicode, the quantity is labeled as UCHAR. For type-prefixed Unicode strings, the padding byte is found after the type byte. The type byte is 4 (indicating SMB_FORMAT_ASCII) independent of whether the string is ASCII or Unicode. For strings whose start addresses are found using offsets within the fixed part of the SMB (as opposed to simply being found at the byte following the preceding field,) it is guaranteed that the offset will be properly aligned. Strings that are never passed in Unicode are: o The protocol strings in the Negotiate SMB request. o The service name string in the Tree Connect And X SMB. When Unicode is negotiated, bit 15 should be set in the FLAGS2 field of every SMB header. Despite the flexible encoding scheme, no field of a data portion may be omitted or included out of order. In addition, neither an WORDCOUNT nor BYTECOUNT of value 0 at the end of a message may be omitted. 3.2 File Names File names in the SMB protocol consist of components separated by a backslash ('\'). Early clients of the SMB protocol required that the name components adhere to an 8.3 format name. These names consist of two parts: a basename of no more than 8 characters, and an extension of no more than 3 characters. The basename and extension are separated by a '.'. All characters are legal in the basename and extension EXCEPT the space character (0x20) and: " . / \[]:+|<>=;,*? If the client has indicated long name support by setting BIT2 in the FLAGS2 field of the SMB header, this indicates that the client is not bound by the 8.3 convention. Specifically this indicates that any SMB which returns file names to the client may return names which do not adhere to the 8.3 convention, and have a total length of up to 255 characters. This capability was introduced with the LM1.2X002 protocol dialect. 3.3 Wildcards Some SMB requests allow wildcards to be given for the filename. The wildcard allows a number of files to be operated on as a unit without Heizer, et al expires December 1996 [Page 38] INTERNET-DRAFT CIFS/1.0 June 1996 having to separately enumerate the files and individually operate on each one from the client. If the client is using 8.3 names, each part of the name ( base (8) or extension (3) ) is treated separately. For long filenames the . in the name is significant even though there is no longer a restriction on the size of each of the components. The ? character is a wild card for a single character. If a filename part commences with one or more "?"s then exactly that number of characters will be matched by the wildcards, e.g., "??x" equals "abx" but not "abcx" or "ax". When a filename part has trailing "?"s then it matches the specified number of characters or less, e.g., "x??" matches "xab", "xa" and "x", but not "xabc". If only "?"s are present in the filename part, then it is handled as for trailing "?"s The * character matches an entire part of the name, as does an empty specification for that part. A part consisting of * means that the rest of the component should be filled with ? and the search should be performed with this wildcard character. For example, "*.abc" or ".abc" match any file with an extension of "abc". "*.*", "*" or "null" match all files in a directory. If the negotiated dialect is "NT LM 0.12" or later, and the client requires MS-DOS wildcard matching semantics, UNICODE wildcards should be translated according to the following rules: Translate the ? literal to > Translate the . literal to " if it is followed by a ? or a * Translate the * literal to < if it is followed by a . The translation can be performed in-place. 3.4 DFS Pathnames A DFS pathname adheres to the standard described in the FileNames section. A DFS enabled client accessing a DFS share should set the Flags2 bit 12 in all name based SMB requests indicating to the server that the enclosed pathname should be resolved in the Distributed File System namespace. The pathname should always have the full file name, including the server name and share name. If the server can resolve the DFS name to a piece of local storage, the local storage will be accessed. If the server determines that the DFS name actually maps to a different server share, the access to the name will fail with the distinguished error STATUS_PATH_NOT_COVERED (SMB Status code 0xC0000257). Heizer, et al expires December 1996 [Page 39] INTERNET-DRAFT CIFS/1.0 June 1996 On receiving this error, the DFS enabled client should ask the server for a referral (see TRANS2_GET_DFS_REFERRAL). The referral request should contain the full file name. The response to the request will contain a list of server and share names to try, and the part of the request file name that junctions to the list of server shares. If the ServerType field of the referral is set to 1 (SMB server), then the client should resubmit the request with the ORIGINAL file name to one of the server shares in the list, once again setting the Flags2 bit 12 bit in the SMB. If the ServerType field is not 1, then the client should strip off the part of the file name that junctions to the server share before resubmitting the request to one of servers in the list. A response to a referral request may elicit a response that does NOT have the StorageServers bit set. In that case, the client should resubmit the REFERRAL REQUEST to one of the servers in the list, until it finally obtains a referral response that has the StorageServers bit set, at which point the client can resubmit the request SMB to one of the listed server shares. If, after getting a referral with the StorageServers bit set and resubmitting the request to one of the server shares in the list, the server fails the request with STATUS_PATH_NOT_COVERED, it must be the case that there is an inconsistency between the view of the DFS namespace held by the server granting the referral and the server listed in that referral. In this case, the client may inform the server granting the referral of this inconsistency via the TRANS2_REPORT_DFS_INCONSISTENCY SMB. 3.5 Time And Date Encoding When SMB requests or responses encode time values, the following describes the various encodings used. struct { USHORT Day : 5; USHORT Month : 4; USHORT Year : 7; } SMB_DATE; The Year field has a range of 0-119, which represents years 1980 - 2099. The Month is encoded as 1-12, and the day ranges from 1-31. Heizer, et al expires December 1996 [Page 40] INTERNET-DRAFT CIFS/1.0 June 1996 struct { USHORT TwoSeconds : 5; USHORT Minutes : 6; USHORT Hours : 5; } SMB_TIME; Hours ranges from 0-23, Minutes range from 0-59, and TwoSeconds ranges from 0-29 representing two second increments within the minute. typedef struct { ULONG LowTime; LONG HighTime; } TIME; TIME indicates a signed 64-bit integer representing either an absolute time or a time interval. Times are specified in units of 100ns. A positive value expresses an absolute time, where the base time (the 64- bit integer with value 0) is the beginning of the year 1601 AD in the Gregorian calendar. A negative value expresses a time interval relative to some base time, usually the current time. typedef unsigned long UTIME; UTIME is the number of seconds since Jan 1, 1970, 00:00:00.0 GMT. 3.6 Access Mode Encoding Various client requests and server responses, such as SMB_COM_OPEN, pass file access modes encoded into a USHORT. The encoding of these is as follows: Heizer, et al expires December 1996 [Page 41] INTERNET-DRAFT CIFS/1.0 June 1996 1111 11 5432 1098 7654 3210 rWrC rLLL rSSS rAAA where: W - Write through mode. No read ahead or write behind allowed on this file or device. When the response is returned, data is expected to be on the disk or device. S - Sharing mode: 0 - Compatibility mode 1 - Deny read/write/execute (exclusive) 2 - Deny write 3 - Deny read/execute 4 - Deny none A - Access mode 0 - Open for reading 1 - Open for writing 2 - Open for reading and writing 3 - Open for execute rSSSrAAA = 11111111 (hex FF) indicates FCB open (???) C - Cache mode 0 - Normal file 1 - Do not cache this file L - Locality of reference 0 - Locality of reference is unknown 1 - Mainly sequential access 2 - Mainly random access 3 - Random access with some locality 4 to 7 - Currently undefined 3.7 Open Function Encoding OPENFUNCTION specifies the action to be taken depending on whether or not the file exists. This word has the following format: Heizer, et al expires December 1996 [Page 42] INTERNET-DRAFT CIFS/1.0 June 1996 bits: 1111 11 5432 1098 7654 3210 rrrr rrrr rrrC rrOO where: C - Create (action to be taken if file does not exist). 0 -- Fail. 1 -- Create file. r - reserved (must be zero). O - Open (action to be taken if file exists). 0 - Fail. 1 - Open file. 2 - Truncate file. 3.8 Open Action Encoding ACTION in the response to an open request specifies the action as a result of the Open request. It has the following format: bits: 1111 11 5432 1098 7654 3210 Lrrr rrrr rrrr rrOO where: L - Lock (single user total file lock status). 0 -- file opened by another user (or mode not supported by server). 1 -- file is opened only by this user at the present time. r - reserved (must be zero). O - Open (action taken on Open). 1 - The file existed and was opened. 2 - The file did not exist but was created. 3 - The file existed and was truncated. 3.9 Device State Encoding DEVICESTATE is encoded as follows: Heizer, et al expires December 1996 [Page 43] INTERNET-DRAFT CIFS/1.0 June 1996 1111 11 5432 1098 7654 3210 BE** TTRR ---- ---- where: B - Blocking 0 => reads/writes block if no data available 1 => reads/writes return immediately if no data E - Endpoint 0 => client end of pipe 1 => server end of pipe TT - Type of pipe 00 => pipe is a byte stream pipe 01 => pipe is a message pipe RR - Read Mode 00 => Read pipe as a byte stream 01 => Read messages from pipe 3.10 File Attribute Encoding When SMB messages exchange file attribute information, it is encoded in 16 bits as: Value Description ======= ===================== 0x01 Read only file 0x02 Hidden file 0x04 System file 0x08 Volume 0x10 Directory 0x20 Archive file others Reserved - must be 0 Heizer, et al expires December 1996 [Page 44] INTERNET-DRAFT CIFS/1.0 June 1996 3.11 Batching Requests ("AndX" Messages) LANMAN1.0 and later dialects of the SMB protocol allow multiple SMB requests to be sent in one message to the server. Messages of this type are called AndX SMBs, and they obey the following rules: o The embedded command does not repeat the SMB header information. Rather the next SMB starts at the WORDCOUNT field. o All multiple (chained) requests must fit within the negotiated transmit size. For example, if SMB_COM_TREE_CONNECT_ANDX included OPENandX SMB_COM_OPEN_ANDX which included SMB_COM_WRITE were sent, they would all have to fit within the negotiated buffer size. This would limit the size of the write. o There is one message sent containing the chained requests and there is one response message to the chained requests. The server may NOT elect to send separate responses to each of the chained requests. o All chained responses must fit within the negotiated transmit size. This limits the maximum value on an embedded SMB_COM_READ for example. It is the client's responsibility to not request more bytes than will fit within the multiple response. o The server will implicitly use the result of the first command in the "X" command. For example the TID obtained via SMB_COM_TREE_CONNECT_ANDX would be used in the embedded SMB_COM_OPEN_ANDX and the FID obtained in the SMB_COM_OPEN_ANDX would be used in the embedded SMB_COM_READ. o Each chained request can only reference the same FID and TID as the other commands in the combined request. The chained requests can be thought of as performing a single (multi-part) operation on the same resource. o The first COMMAND to encounter an error will stop all further processing of embedded commands. The server will not back out commands that succeeded. Thus if a chained request contained SMB_COM_OPEN_ANDX and SMB_COM_READ and the server was able to open the file successfully but the read encountered an error, the file would remain open. This is exactly the same as if the requests had been sent separately. o If an error occurs while processing chained requests, the last response (of the chained responses in the buffer) will be the one which encountered the error. Other unprocessed chained requests will have been ignored when the server encountered the error and will not be represented in the chained response. Actually the last valid ANDXCOMMAND (if any) will represent the SMB on which the error occurred. If no valid ANDXCOMMAND is present, then the error occurred on the first request/response and COMMAND contains the Heizer, et al expires December 1996 [Page 45] INTERNET-DRAFT CIFS/1.0 June 1996 command which failed. In all cases the error information are returned in the SMB header at the start of the response buffer. o Each chained request and response contains the offset (from the start of the SMB header) to the next chained request/response (in the ANDXOFFSET field in the various "and X" protocols defined later e.g. SMB_COM_OPEN_ANDX). This allows building the requests unpacked. There may be space between the end of the previous request (as defined by WORDCOUNT and BYTECOUNT) and the start of the next chained request. This simplifies the building of chained protocol requests. Note that because the client must know the size of the data being returned in order to post the correct number of receives (e.g. SMB_COM_TRANSACTION, SMB_COM_READ_MPX), the data in each response SMB is expected to be truncated to the maximum number of 512 byte blocks (sectors) which will fit (starting at a DWORD boundary) in the negotiated buffer size with the odd bytes remaining (if any) in the final buffer. 3.12 "Transaction" Style Subprotocols SMB_COM_TRANSACTION performs a symbolically named transaction. This transaction is known only by a name (no file handle used). SMB_COM_TRANSACTION2 likewise performs a transaction, but a word parameter is used to identify the transaction instead of a name. SMB_COM_NT_TRANSACTION is used for commands that potentially need to transfer a large amount of data (greater than 64K bytes). Heizer, et al expires December 1996 [Page 46] INTERNET-DRAFT CIFS/1.0 June 1996 3.12.1 SMB_COM_TRANSACTION and SMB_COM_TRANSACTION2 Formats Primary Client Request Description =============================== ==================================== Command SMB_COM_TRANSACTION or SMB_COM_TRANSACTION2 UCHAR WordCount; Count of parameter words; value = (14 + SetupCount) USHORT TotalParameterCount; Total parameter bytes being sent USHORT TotalDataCount; Total data bytes being sent USHORT MaxParameterCount; Max parameter bytes to return USHORT MaxDataCount; Max data bytes to return UCHAR MaxSetupCount; Max setup words to return UCHAR Reserved; USHORT Flags; Additional information: bit 0 - also disconnect TID in TID bit 1 - one-way transaction (no resp) ULONG Timeout; USHORT Reserved2; USHORT ParameterCount; Parameter bytes sent this buffer USHORT ParameterOffset; Offset (from header start) to Parameters USHORT DataCount; Data bytes sent this buffer USHORT DataOffset; Offset (from header start) to data UCHAR SetupCount; Count of setup words UCHAR Reserved3; Reserved (pad above to word) Heizer, et al expires December 1996 [Page 47] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT Setup[SetupCount]; Setup words (# = SetupWordCount) USHORT ByteCount; Count of data bytes STRING Name[]; Name of transaction (NULL if SMB_COM_TRANSACTION2) UCHAR Pad[]; Pad to SHORT or LONG UCHAR Parameters[ Parameter bytes (# = ParameterCount) ParameterCount]; UCHAR Pad1[]; Pad to SHORT or LONG UCHAR Data[ DataCount ]; Data bytes (# = DataCount) Interim Server Response Description =============================== ==================================== UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 Heizer, et al expires December 1996 [Page 48] INTERNET-DRAFT CIFS/1.0 June 1996 Secondary Client Request Description =============================== ==================================== Command SMB_COM_TRANSACTION_SECONDARY UCHAR WordCount; Count of parameter words = 8 USHORT TotalParameterCount; Total parameter bytes being sent USHORT TotalDataCount; Total data bytes being sent USHORT ParameterCount; Parameter bytes sent this buffer USHORT ParameterOffset; Offset (from header start) to Parameters USHORT ParameterDisplacement; Displacement of these Parameter bytes USHORT DataCount; Data bytes sent this buffer USHORT DataOffset; Offset (from header start) to data USHORT DataDisplacement; Displacement of these data bytes USHORT Fid; FID for handle based requests, else 0xFFFF. This field is present only if this is an SMB_COM_TRANSACTION2 request. USHORT ByteCount; Count of data bytes UCHAR Pad[]; Pad to SHORT or LONG UCHAR Parameter bytes (# = ParameterCount) Parameters[ParameterCount]; UCHAR Pad1[]; Pad to SHORT or LONG UCHAR Data[DataCount]; Data bytes (# = DataCount) Heizer, et al expires December 1996 [Page 49] INTERNET-DRAFT CIFS/1.0 June 1996 Server Response Description =============================== ==================================== UCHAR WordCount; Count of data bytes; value = 10 + SETUPCOUNT USHORT TotalParameterCount; Total parameter bytes being sent USHORT TotalDataCount; Total data bytes being sent USHORT Reserved; USHORT ParameterCount; Parameter bytes sent this buffer USHORT ParameterOffset; Offset (from header start) to Parameters USHORT ParameterDisplacement; Displacement of these Parameter bytes USHORT DataCount; Data bytes sent this buffer USHORT DataOffset; Offset (from header start) to data USHORT DataDisplacement; Displacement of these data bytes UCHAR SetupCount; Count of setup words UCHAR Reserved2; Reserved (pad above to word) USHORT Setup[SetupWordCount]; Setup words (# = SetupWordCount) USHORT ByteCount; Count of data bytes UCHAR Pad[]; Pad to SHORT or LONG UCHAR Parameter bytes (# = ParameterCount) Parameters[ParameterCount]; UCHAR Pad1[]; Pad to SHORT or LONG UCHAR Data[DataCount]; Data bytes (# = DataCount) 3.12.2 SMB_COM_NT_TRANSACTION Formats Primary Client Request Description Heizer, et al expires December 1996 [Page 50] INTERNET-DRAFT CIFS/1.0 June 1996 =============================== ==================================== UCHAR WordCount; Count of parameter words; value = (19 + SetupCount) UCHAR MaxSetupCount; Max setup words to return USHORT Reserved; ULONG TotalParameterCount; Total parameter bytes being sent ULONG TotalDataCount; Total data bytes being sent ULONG MaxParameterCount; Max parameter bytes to return ULONG MaxDataCount; Max data bytes to return ULONG ParameterCount; Parameter bytes sent this buffer ULONG ParameterOffset; Offset (from header start) to Parameters ULONG DataCount; Data bytes sent this buffer ULONG DataOffset; Offset (from header start) to data UCHAR SetupCount; Count of setup words USHORT Function; The transaction function code UCHAR Buffer[1]; USHORT Setup[SetupWordCount]; Setup words USHORT ByteCount; Count of data bytes UCHAR Pad1[]; Pad to LONG UCHAR Parameter bytes Parameters[ParameterCount]; UCHAR Pad2[]; Pad to LONG UCHAR Data[DataCount]; Data bytes Heizer, et al expires December 1996 [Page 51] INTERNET-DRAFT CIFS/1.0 June 1996 Interim Server Response Description =============================== ==================================== UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 Heizer, et al expires December 1996 [Page 52] INTERNET-DRAFT CIFS/1.0 June 1996 Secondary Client Request Description =============================== ==================================== UCHAR WordCount; Count of parameter words = 18 UCHAR Reserved[3]; MBZ ULONG TotalParameterCount; Total parameter bytes being sent ULONG TotalDataCount; Total data bytes being sent ULONG ParameterCount; Parameter bytes sent this buffer ULONG ParameterOffset; Offset (from header start) to Parameters ULONG ParameterDisplacement; Specifies the offset from the start of the overall parameter block to the parameter bytes that are contained in this message ULONG DataCount; Data bytes sent this buffer ULONG DataOffset; Offset (from header start) to data ULONG DataDisplacement; Specifies the offset from the start of the overall data block to the data bytes that are contained in this message. UCHAR Reserved1; USHORT ByteCount; Count of data bytes UCHAR Pad1[]; Pad to LONG UCHAR Parameter bytes Parameters[ParameterCount]; UCHAR Pad2[]; Pad to LONG UCHAR Data[DataCount]; Data bytes Server Response Description Heizer, et al expires December 1996 [Page 53] INTERNET-DRAFT CIFS/1.0 June 1996 =============================== ==================================== UCHAR WordCount; Count of data bytes; value = 18 + SetupCount UCHAR Reserved[3]; ULONG TotalParameterCount; Total parameter bytes being sent ULONG TotalDataCount; Total data bytes being sent ULONG ParameterCount; Parameter bytes sent this buffer ULONG ParameterOffset; Offset (from header start) to Parameters ULONG ParameterDisplacement; Specifies the offset from the start of the overall parameter block to the parameter bytes that are contained in this message ULONG DataCount; Data bytes sent this buffer ULONG DataOffset; Offset (from header start) to data ULONG DataDisplacement; Specifies the offset from the start of the overall data block to the data bytes that are contained in this message. UCHAR SetupCount; Count of setup words USHORT Setup[SetupWordCount]; Setup words USHORT ByteCount; Count of data bytes UCHAR Pad1[]; Pad to LONG UCHAR Parameter bytes Parameters[ParameterCount]; UCHAR Pad2[]; Pad to SHORT or LONG UCHAR Data[DataCount]; Data bytes Heizer, et al expires December 1996 [Page 54] INTERNET-DRAFT CIFS/1.0 June 1996 3.12.3 Functional Description The SMB_COM_TRANSACTION command's scope includes named pipes and mailslots. Where the resource is unidirectional (such as class 2 writes to mailslots), bit1 of Flags in the request can be set indicating that no response is needed. The other transactions accommodate IOCTL requests and file system requests which require the transfer of an extended attribute list. The transaction Setup information and/or Parameters define functions specific to a particular resource on a particular server. Therefore the functions supported are not defined by the protocol, but by client and server implementations. The transaction protocol simply provides a means of delivering them and retrieving the results. The number of bytes needed in order to perform the transaction request may be more than will fit in a single buffer. At the time of the request, the client knows the number of parameter and data bytes expected to be sent and passes this information to the server via the primary request (TotalParameterCount and TotalDataCount). This may be reduced by lowering the total number of bytes expected (TotalParameterCount and TotalDataCount) in each (if any) secondary request. When the amount of parameter bytes received (total of each ParameterCount) equals the total amount of parameter bytes expected (smallest TotalParameterCount) received, then the server has received all the parameter bytes. Likewise, when the amount of data bytes received (total of each DATACOUNT) equals the total amount of data bytes expected (smallest TOTALDATACOUNT) received, then the server has received all the data bytes. The parameter bytes should normally be sent first followed by the data bytes. However, the server knows where each begins and ends in each buffer by the offset fields (PARAMETEROFFSET and DATAOFFSET) and the length fields (PARAMETERCOUNT and DATACOUNT). The displacement of the bytes (relative to start of each) is also known (PARAMETERDISPLACEMENT and DATADISPLACEMENT). Thus the server is able to reassemble the parameter and data bytes should the individual requests be received out of sequence. If all parameter bytes and data bytes fit into a single buffer, then no interim response is expected and no secondary request is sent. The client knows the maximum amount of data bytes and parameter bytes which the server may return (from MAXPARAMETERCOUNT and MAXDATACOUNT of the request). Thus the client initializes its bytes expected variables to these values. The server then informs the client of the actual amounts being returned via each message of the server response Heizer, et al expires December 1996 [Page 55] INTERNET-DRAFT CIFS/1.0 June 1996 (TOTALPARAMETERCOUNT and TOTALDATACOUNT). The server may reduce the expected bytes by lowering the total number of bytes expected (TOTALPARAMETERCOUNT and/or TOTALDATACOUNT) in each (any) response. When the amount of parameter bytes received (total of each PARAMETERCOUNT) equals the total amount of parameter bytes expected (smallest TOTALPARAMETERCOUNT) received, then the client has received all the parameter bytes. Likewise, when the amount of data bytes received (total of each DATACOUNT) equals the total amount of data bytes expected (smallest TOTALDATACOUNT) received, then the client has received all the data bytes. The parameter bytes should normally be returned first followed by the data bytes. However, the client knows where each begins and ends in each buffer by the offset fields (PARAMETEROFFSET and DATAOFFSET) and the length fields (PARAMETERCOUNT and DATACOUNT). The displacement of the bytes (relative to start of each) is also known (PARAMETERDISPLACEMENT and DATADISPLACEMENT). The client is able to reassemble the parameter and data bytes should the server responses be received out of sequence. If a connectionless transport is being used, the transaction requests must be properly sequenced in the CONNECTIONLESS.SEQUENCENUMBER SMB header field. The MID of any secondary client requests must match the MID of the primary client request. The server responds to each request piece except the last one with a response indicating that the server is ready for the next piece. The last piece is responded to with the first piece of the result data. The client then sends an SMB_COM_TRANSACTION_SECONDARY SMB with PARAMETERDISPLACEMENT set to the number of parameter bytes received so far and DATADISPLACEMENT set to the number of data bytes received so far and PARAMETERCOUNT, PARAMETEROFFSET, DATACOUNT, and DATAOFFSET set to zero (0). The server responds with the next piece of the transaction result. The process is repeated until all of the response information has been received. When the transaction has been completed, the client must send another sequenced command (such as an SMB_COM_ECHO) to the server to allow the server to know that the final piece was received and that resources allocated to the transaction command may be released. The flow for these transactions over a connection oriented transport is: 1. The client sends the primary client request identifying the total bytes (both parameters and data) which are expected to be sent and contains the set up words and as many of the parameter and data bytes as will fit in a negotiated size buffer. This request also identifies the maximum number of bytes (setup, parameters and data) the server is to return on the transaction completion. If all the bytes fit in the single buffer, skip to step 4. Heizer, et al expires December 1996 [Page 56] INTERNET-DRAFT CIFS/1.0 June 1996 2. The server responds with a single interim response meaning "OK, send the remainder of the bytes" or (if error response) terminate the transaction. 3. The client then sends another buffer full of bytes to the server. This step is repeated until all of the bytes are sent and received. 4. The Server sets up and performs the transaction with the information provided. 5. Upon completion of the transaction, the server sends back (up to) the number of parameter and data bytes requested (or as many as will fit in the negotiated buffer size). This step is repeated until all result bytes have been returned. The flow for the transaction protocol when the request parameters and data do not all fit in a single buffer is: Client <-> Server =============================== ==== ============================== Primary TRANSACTION request -> <- Interim Server Response Secondary TRANSACTION request 1 -> Secondary TRANSACTION request 2 -> Secondary TRANSACTION request N -> <- TRANSACTION response 1 <- TRANSACTION response 2 <- TRANSACTION response m The flow for the transaction protocol when the request parameters and data does all fit in a single buffer is: Heizer, et al expires December 1996 [Page 57] INTERNET-DRAFT CIFS/1.0 June 1996 Client <-> Server =============================== ==== ============================== Primary TRANSACTION request -> <- TRANSACTION response 1 <- TRANSACTION response 2 <- TRANSACTION response m The flow for the transaction protocol over a connectionless transport is: 1. The client sends the primary client request identifying the total bytes (both parameters and data) which are expected to be sent and contains the set up words and as many of the parameter and data bytes as will fit in a negotiated size buffer. This request also identifies the maximum number of bytes (setup, parameters and data) the server is to return on completion. If all the bytes fit in the single buffer, skip to step 4. 2. The server responds with a single interim response meaning "OK, send the remainder of the bytes" or (if error response) terminate the transaction. 3. The client then sends another buffer full of bytes to the server. The server responds with an interim server response. This step is repeated until all of the bytes are sent and received. 4. The Server sets up and performs the transaction with the information provided. 5. Upon completion of the transaction, the server sends back (up to) the number of parameter and data bytes requested (or as many as will fit in the negotiated buffer size). 6. The client responds with a transaction secondary request. The server sends back more response data. This step is repeated until all result bytes have been returned. 7. The client sends a sequenced request to the server such as SMB_COM_ECHO The primary transaction request through the final response make up the complete transaction exchange, thus the TID, PID, UID and MID must remain Heizer, et al expires December 1996 [Page 58] INTERNET-DRAFT CIFS/1.0 June 1996 constant and can be used as appropriate by both the server and the client. Of course, other SMB requests may intervene as well. There are (at least) three ways that actual server responses have been observed to differ from what might be expected. First, some servers will send Pad bytes to move the DataOffset to a 2- or 4-byte boundary even if there are no data bytes; the point here is that the ByteCount must be used instead of ParameterOffset plus ParameterCount to infer the actual message length. Second, some servers always return MaxParameterCount bytes even if the particular Transact2 has no parameter response. Finally, in case of an error, some servers send the "traditional WordCount==0/ByteCount==0" response while others generate a Transact response format. 3.13 Valid SMB Requests by Negotiated Dialect The following SMB messages may be exchanged by SMB clients and servers if the "PC NETWORK PROGRAM 1.0" dialect is negotiated: SMB_COM_CREATE_DIRECTORY SMB_COM_DELETE_DIRECTORY SMB_COM_OPEN SMB_COM_CREATE SMB_COM_CLOSE SMB_COM_FLUSH SMB_COM_DELETE SMB_COM_RENAME SMB_COM_QUERY_INFORMATION SMB_COM_SET_INFORMATION SMB_COM_READ SMB_COM_WRITE SMB_COM_LOCK_BYTE_RANGE SMB_COM_UNLOCK_BYTE_RANGE SMB_COM_CREATE_TEMPORARY SMB_COM_CREATE_NEW SMB_COM_CHECK_DIRECTORY SMB_COM_PROCESS_EXIT SMB_COM_SEEK SMB_COM_TREE_CONNECT SMB_COM_TREE_DISCONNECT SMB_COM_NEGOTIATE SMB_COM_QUERY_INFORMATION_DISK SMB_COM_SEARCH SMB_COM_OPEN_PRINT_FILE SMB_COM_WRITE_PRINT_FILE SMB_COM_CLOSE_PRINT_FILE SMB_COM_GET_PRINT_QUEUE If the "LANMAN 1.0" dialect is negotiated, all of the messages in the previous list must be supported. Clients negotiating LANMAN 1.0 and Heizer, et al expires December 1996 [Page 59] INTERNET-DRAFT CIFS/1.0 June 1996 higher dialects will probably no longer send SMB_COM_PROCESS_EXIT, and the response format for SMB_COM_NEGOTIATE is modified as well. New messages introduced with the LANMAN 1.0 dialect are: SMB_COM_LOCK_AND_READ SMB_COM_WRITE_AND_UNLOCK SMB_COM_READ_RAW SMB_COM_READ_MPX SMB_COM_WRITE_MPX SMB_COM_WRITE_RAW SMB_COM_WRITE_COMPLETE SMB_COM_WRITE_MPX_SECONDARY SMB_COM_SET_INFORMATION2 SMB_COM_QUERY_INFORMATION2 SMB_COM_LOCKING_ANDX SMB_COM_TRANSACTION SMB_COM_TRANSACTION_SECONDARY SMB_COM_IOCTL SMB_COM_IOCTL_SECONDARY SMB_COM_COPY SMB_COM_MOVE SMB_COM_ECHO SMB_COM_WRITE_AND_CLOSE SMB_COM_OPEN_ANDX SMB_COM_READ_ANDX SMB_COM_WRITE_ANDX SMB_COM_SESSION_SETUP_ANDX SMB_COM_TREE_CONNECT_ANDX SMB_COM_FIND SMB_COM_FIND_UNIQUE SMB_COM_FIND_CLOSE The "LM1.2X002" dialect introduces these new SMBs: SMB_COM_TRANSACTION2 SMB_COM_TRANSACTION2_SECONDARY SMB_COM_FIND_CLOSE2 SMB_COM_LOGOFF_ANDX Heizer, et al expires December 1996 [Page 60] INTERNET-DRAFT CIFS/1.0 June 1996 "NT LM 0.12" dialect introduces: SMB_COM_NT_TRANSACT SMB_COM_NT_TRANSACT_SECONDARY SMB_COM_NT_CREATE_ANDX SMB_COM_NT_CANCEL SMB_COM_NT_RENAME SMB_COM_READ_BULK SMB_COM_WRITE_BULK SMB_COM_WRITE_BULK_DATA 4. SMB Requests This section lists the "best practice" SMB requests -- ones that would permit a client to exercise full CIFS functionality and optimum performance when interoperating with a server speaking the latest dialect as of this writing ("NT LM 0.12"). Note that, as of this writing, no existing client restricts itself to only these requests, so no useful server can be written that supports just them. The classification is provided so that future clients will be written to permit future servers to be simpler. 4.1 Session Requests 4.1.1 NEGOTIATE: Negotiate Protocol Client Request Description ============================ ======================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes; min = 2 struct { UCHAR BufferFormat; 0x02 -- Dialect UCHAR DialectName[]; ASCII null-terminated string } Dialects[]; The Client sends a list of dialects that it can communicate with. The response is a selection of one of those dialects (numbered 0 through n) or -1 (hex FFFF) indicating that none of the dialects were acceptable. Heizer, et al expires December 1996 [Page 61] INTERNET-DRAFT CIFS/1.0 June 1996 The negotiate message is binding on the virtual circuit and must be sent. One and only one negotiate message may be sent, subsequent negotiate requests will be rejected with an error response and no action will be taken. The protocol does not impose any particular structure to the dialect strings. Implementers of particular protocols may choose to include, for example, version numbers in the string. If the server does not understand any of the dialect strings, or if PC NETWORK PROGRAM 1.0 is the chosen dialect, the response format is Server Response Description ============================ ======================================= UCHAR WordCount; Count of parameter words = 1 USHORT DialectIndex; Index of selected dialect USHORT ByteCount; Count of data bytes = 0 Heizer, et al expires December 1996 [Page 62] INTERNET-DRAFT CIFS/1.0 June 1996 If the chosen dialect is greater than core up to and including LANMAN2.1, the protocol response format is Server Response Description ============================ ======================================= UCHAR WordCount; Count of parameter words = 13 USHORT DialectIndex; Index of selected dialect USHORT SecurityMode; Security mode: bit 0: 0 = share, 1 = user bit 1: 1 = use challenge/response authentication USHORT MaxBufferSize; Max transmit buffer size (>= 1024) USHORT MaxMpxCount; Max pending multiplexed requests USHORT MaxNumberVcs; Max VCs between client and server USHORT RawMode; Raw modes supported: bit 0: 1 = Read Raw supported bit 1: 1 = Write Raw supported ULONG SessionKey; Unique token identifying this session SMB_TIME ServerTime; Current time at server SMB_DATE ServerDate; Current date at server USHORT ServerTimeZone; Current time zone at server USHORT EncryptionKeyLength; MBZ if this is not LM2.1 USHORT Reserved; MBZ USHORT ByteCount Count of data bytes UCHAR EncryptionKey[]; The challenge encryption key STRING PrimaryDomain[]; The server's primary domain Heizer, et al expires December 1996 [Page 63] INTERNET-DRAFT CIFS/1.0 June 1996 MaxBufferSize is the size of the largest message which the client can legitimately send to the server If bit0 of the Flags field is set in the negotiate response, this indicates the server supports the SMB_COM_LOCK_AND_READ and SMB_COM_WRITE_AND_UNLOCK client requests. If the SecurityMode field indicates the server is running in user mode, the client must send appropriate SMB_COM_SESSION_SETUP_ANDX requests before the server will allow the client to access resources. If the SecurityMode fields indicates the client should use challenge/response authentication, the client should use the authentication mechanism specified in section 2.10. Clients should submit no more than MaxMpxCount distinct unanswered SMBs to the server when using multiplexed reads or writes (see sections 5.13 and 5.24) Clients using the "MICROSOFT NETWORKS 1.03" dialect use a different form of raw reads than documented here, and servers are better off setting RawMode in this response to 0 for such sessions. If the negotiated dialect is "DOS LANMAN2.1" or "LANMAN2.1", then PrimaryDomain string should be included in this response. Heizer, et al expires December 1996 [Page 64] INTERNET-DRAFT CIFS/1.0 June 1996 If the negotiated dialect is NT LM 0.12, the response format is Server Response Description ========================== ========================================= UCHAR WordCount; Count of parameter words = 17 USHORT DialectIndex; Index of selected dialect UCHAR SecurityMode; Security mode: bit 0: 0 = share, 1 = user bit 1: 1 = encrypt passwords USHORT MaxMpxCount; Max pending multiplexed requests USHORT MaxNumberVcs; Max VCs between client and server ULONG MaxBufferSize; Max transmit buffer size ULONG MaxRawSize; Maximum raw buffer size ULONG SessionKey; Unique token identifying this session ULONG Capabilities; Server capabilities ULONG SystemTimeLow; System (UTC) time of the server (low). ULONG SystemTimeHigh; System (UTC) time of the server (high). USHORT ServerTimeZone; Time zone of server (min from UTC) UCHAR EncryptionKeyLength; Length of encryption key. USHORT ByteCount; Count of data bytes UCHAR EncryptionKey[]; The challenge encryption key UCHAR OemDomainName[]; The name of the domain (in OEM chars) In addition to the definitions above, MaxBufferSize is the size of the largest message which the client can legitimately send to the server. If the client is using a connectionless protocol, MaxBufferSize must be set to the smaller of the server's internal buffer size and the amount of data which can be placed in a response packet. Heizer, et al expires December 1996 [Page 65] INTERNET-DRAFT CIFS/1.0 June 1996 MaxRawSize specifies the maximum message size the server can send or receive for SMB_COM_WRITE_RAW or SMB_COM_READ_RAW. Connectionless clients must set SID to 0 in the SMB request header. Capabilities allows the server to tell the client what it supports. The bit definitions are: Capability Name Encoding Meaning ==================== ======== ===================================== CAP_RAW_MODE 0x0001 The server supports SMB_COM_READ_RAW and SMB_COM_WRITE_RAW CAP_MPX_MODE 0x0002 The server supports SMB_COM_READ_MPX and SMB_COM_WRITE_MPX CAP_UNICODE 0x0004 The server supports Unicode strings CAP_LARGE_FILES 0x0008 The server supports large files with 64 bit offsets CAP_NT_SMBS 0x0010 The server supports the SMBs particular to the NT LM 0.12 dialect CAP_RPC_REMOTE_APIS 0x0020 The sever supports remote API requests via RPC CAP_NT_STATUS 0x0040 The server can respond with 32 bit status codes in Status.NtStatus CAP_LEVEL_II_OPLOCKS 0x0080 The server supports level 2 oplocks CAP_LOCK_AND_READ 0x0100 The server supports the SMB_COM_LOCK_AND_READ SMB CAP_NT_FIND 0x0200 CAP_DFS 0x1000 This server is DFS aware CAP_LARGE_READX 0x4000 The server supports SMB_COM_READ_ANDX requests which exceed the negotiated buffer size Heizer, et al expires December 1996 [Page 66] INTERNET-DRAFT CIFS/1.0 June 1996 4.1.1.1 Errors SUCCESS/SUCCESS ERRSRV/ERRerror Heizer, et al expires December 1996 [Page 67] INTERNET-DRAFT CIFS/1.0 June 1996 4.1.2 SESSION_SETUP_ANDX: Session Setup This SMB is used to further "Set up" the session normally just established via the negotiate protocol. One primary function is to perform a "user logon" in the case where the server is in USER LEVEL security mode. The UID in the SMB header is set by the client to be the userid desired for the ACCOUNTNAME and validated by the ACCOUNTPASSWORD. If the negotiated protocol is prior to NT LM 0.12, the format of SMB_COM_SESSION_SETUP_ANDX is: Client Request Description ============================== ===================================== UCHAR WordCount; Count of parameter words = 10 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT MaxBufferSize; Client maximum buffer size USHORT MaxMpxCount; Actual maximum multiplexed pending requests USHORT VcNumber; 0 = first (only), nonzero=additional VC number ULONG SessionKey; Session key (valid iff VcNumber != 0) USHORT PasswordLength; Account password size ULONG Reserved; Must be 0 USHORT ByteCount; Count of data bytes; min = 0 UCHAR AccountPassword[]; Account Password STRING AccountName[]; Account Name STRING PrimaryDomain[]; Client's primary domain STRING NativeOS[]; Client's native operating system Heizer, et al expires December 1996 [Page 68] INTERNET-DRAFT CIFS/1.0 June 1996 STRING NativeLanMan[]; Client's native LAN Manager type and the response is: Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 3 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT Action; Request mode: bit0 = logged in as GUEST USHORT ByteCount; Count of data bytes STRING NativeOS[]; Server's native operating system STRING NativeLanMan[]; Server's native LAN Manager type STRING PrimaryDomain[]; Server's primary domain If the server is in "share level security mode", the account name and passwd should be ignored by the server. If challenge/response authentication is not being used, AccountPassword should be a null terminated ASCII string with PasswordLength set to the string size including the null; the password will case insensitive. If challenge/response authentication is being used (see section 2.10), then AccountPassword will be the response to the server's challenge, and PasswordLength should be set to its length. The server validates the name and password supplied and if valid, it registers the user identifier on this session as representing the specified AccountName. The Uid field in the SMB header will then be used to validate access on subsequent SMB requests. The SMB requests where permission checks are required are those which refer to a symbolically named resource such as SMB_COM_OPEN, SMB_COM_RENAME, Heizer, et al expires December 1996 [Page 69] INTERNET-DRAFT CIFS/1.0 June 1996 SMB_COM_DELETE, etc.. The value of the Uid is relative to a specific client/server session so it is possible to have the same Uid value represent two different users on two different sessions at the server. Multiple session setup commands may be sent to register additional users on this session. If the server receives an additional SMB_COM_SESSION_SETUP_ANDX, only the Uid, AccountName and AccountPassword fields need contain valid values (the server MUST ignore the other fields). The client writes the name of its domain in PrimaryDomain if it knows what the domain name is. If the domain name is unknown, the client either encodes it as a NULL string, or as a question mark. If BIT0 of Action is set, this informs the client that although the server did not recognize the AccountName, it logged the user in as a guest. This is optional behavior by the server, and in any case one would ordinarily expect guest privileges to limited. Another function of the Session Set Up protocol is to inform the server of the maximum values which will be utilized by this client. Here MaxBufferSize is the maximum message size which the client can receive. Thus although the server may support 16k buffers (as returned in the SMB_COM_NEGOTIATE response), if the client only has 4k buffers, the value of MaxBufferSize here would be 4096. The minimum allowable value for MaxBufferSize is 1024. The SMB_COM_NEGOTIATE response includes the server buffer size supported. Thus this is the maximum SMB message size which the client can send to the server. This size may be larger than the size returned to the server from the client via the SMB_COM_SESSION_SETUP_AND X protocol which is the maximum SMB message size which the server may send to the client. Thus if the server's buffer size were 4k and the client's buffer size were only 2K, the client could send up to 4k (standard) write requests but must only request up to 2k for (standard) read requests. The field, MaxMpxCount informs the server of the maximum number of requests which the client will have outstanding to the server simultaneously (see sections 5.13 and 5.24). The VcNumber field specifies whether the client wants this to be the first VC or an additional VC. The values for MaxBufferSize, MaxMpxCount, and VcNumber must be less than or equal to the maximum values supported by the server as returned in the SMB_COM_NEGOTIATE response. If the server gets a SMB_COM_SESSION_SETUP_ANDX request with VcNumber of 0 and other VCs are still connected to that client, they will be aborted thus freeing any resources held by the server. This condition could occur if the client was rebooted and reconnected to the server before the transport level had informed the server of the previous VC termination. Heizer, et al expires December 1996 [Page 70] INTERNET-DRAFT CIFS/1.0 June 1996 If the negotiated SMB dialect is "NT LM 0.12" or later, the format of the response SMB is unchanged, but the request is: Client Request Description ============================== ===================================== UCHAR WordCount; Count of parameter words = 13 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT MaxBufferSize; Client's maximum buffer size USHORT MaxMpxCount; Actual maximum multiplexed pending requests USHORT VcNumber; 0 = first (only), nonzero=additional VC number ULONG SessionKey; Session key (valid iff VcNumber != 0) USHORT Account password size, ANSI CaseInsensitivePasswordLength; USHORT Account password size, Unicode CaseSensitivePasswordLength; ULONG Reserved; must be 0 ULONG Capabilities; Client capabilities USHORT ByteCount; Count of data bytes; min = 0 UCHAR Account Password, ANSI CaseInsensitivePassword[]; UCHAR CaseSensitivePassword[]; Account Password, Unicode STRING AccountName[]; Account Name, Unicode STRING PrimaryDomain[]; Client's primary domain, Unicode STRING NativeOS[]; Client's native operating system, Unicode Heizer, et al expires December 1996 [Page 71] INTERNET-DRAFT CIFS/1.0 June 1996 STRING NativeLanMan[]; Client's native LAN Manager type, Unicode The client expresses its capabilities to the server encoded in the Capabilities field: Capability Name Encoding Description ======================== ========= ================================ CAP_UNICODE 0x0004 The client can use UNICODE strings CAP_LARGE_FILES 0x0008 The client can deal with files having 64 bit offsets CAP_NT_SMBS 0x0010 The client understands the SMBs introduced with the NT LM 0.12 dialect. Implies CAP_NT_FIND. CAP_NT_FIND 0x0200 CAP_NT_STATUS 0x0040 The client can receive 32 bit errors encoded in STATUS.NTSTATUS CAP_LEVEL_II_OPLOCKS 0x0080 The client understands Level II oplocks The entire message sent and received including the optional ANDX SMB must fit in the negotiated maximum transfer size. The following are the only valid SMB commands for AndXCommand for SMB_COM_SESSION_SETUP_ANDX SMB_COM_TREE_CONNECT_ANDX SMB_COM_OPEN SMB_COM_OPEN_ANDX SMB_COM_CREATE SMB_COM_CREATE_NEW SMB_COM_CREATE_DIRECTORY SMB_COM_DELETE SMB_COM_DELETE_DIRECTORY SMB_COM_FIND SMB_COM_FIND_UNIQUE SMB_COM_COPY SMB_COM_RENAME Heizer, et al expires December 1996 [Page 72] INTERNET-DRAFT CIFS/1.0 June 1996 SMB_COM_NT_RENAME SMB_COM_CHECK_DIRECTORY SMB_COM_QUERY_INFORMATION SMB_COM_SET_INFORMATION SMB_COM_NO_ANDX_COMMAND SMB_COM_OPEN_PRINT_FILE SMB_COM_GET_PRINT_QUEUE SMB_COM_TRANSACTION 4.1.2.1 Errors ERRSRV/ERRerror - no NEG_PROT issued ERRSRV/ERRbadpw - password not correct for given username ERRSRV/ERRtoomanyuids - maximum number of users per session exceeded ERRSRV/ERRnosupport - chaining of this request to the previous one is not supported 4.1.3 LOGOFF_ANDX: User Logoff This SMB is the inverse of SMB_COM_SESSION_SETUP_ANDX. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 2 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT ByteCount; Count of data bytes = 0 Server Response Description Heizer, et al expires December 1996 [Page 73] INTERNET-DRAFT CIFS/1.0 June 1996 ================================== ================================= UCHAR WordCount; Count of parameter words = 2 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT ByteCount; Count of data bytes = 0 The user represented by UID in the SMB header is logged off. The server closes all files currently open by this user, and invalidates any outstanding requests with this UID. SMB_COM_SESSION_SETUP_ANDX is the only valid AndXCommand. for this SMB. 4.1.3.1 Errors ERRSRV/invnid - TID was invalid ERRSRV/baduid - UID was invalid 4.1.4 TREE_CONNECT_ANDX: Tree Connect Client Request Description ================================= ================================= UCHAR WordCount; Count of parameter words = 4 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT Flags; Additional information bit 0 set = disconnect Tid Heizer, et al expires December 1996 [Page 74] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT PasswordLength; Length of Password[] USHORT ByteCount; Count of data bytes; min = 3 UCHAR Password[]; Password STRING Path[]; Server name and share name STRING Service[]; Service name This message generally functions just as SMB_COM_TREE_CONNECT, except it allows an AndXCommand to follow. Because PASSWORD may be encrypted, it is a variable length field with the length specified by PASSWORDLENGTH. If password encryption is not being used, PASSWORD should be a null terminated ASCII string with PASSWORDLENGTH set to the string size including the terminating null. SERVICE is as described for SMB_COM_TREE_CONNECT. If BIT0 of FLAGS is set, the tree connection to TID in the SMB header should be disconnected. If this tree disconnect fails, the error should be ignored. If the negotiated dialect is earlier than DOS LANMAN2.1, the response to this SMB is: Server Response Description ================================ =================================== UCHAR WordCount; Count of parameter words = 2 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT ByteCount; Count of data bytes; min = 3 Heizer, et al expires December 1996 [Page 75] INTERNET-DRAFT CIFS/1.0 June 1996 If the negotiated is DOS LANMAN2.1 or later, the response to this SMB is: Server Response Description ================================ =================================== UCHAR WordCount; Count of parameter words = 3 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT OptionalSupport; Optional support bits USHORT ByteCount; Count of data bytes; min = 3 UCHAR Service[]; Service type connected to. Always ANSII STRING NativeFileSystem[]; Native file system for this tree NativeFileSystem is the name of the filesystem; values to be expected include FAT, NTFS, etc. Heizer, et al expires December 1996 [Page 76] INTERNET-DRAFT CIFS/1.0 June 1996 OptionalSupport bits has the encoding: Name Encoding Description ============================= ========= ========================== SMB_SUPPORT_SEARCH_BITS 0x0001 SMB_SHARE_IS_IN_DFS 0x0002 Some servers negotiate "DOS LANMAN2.1" dialect or later and still send the "downlevel" (i.e. wordcount==2) response. Valid AndX following commands are SMB_COM_OPEN SMB_COM_OPEN_ANDX SMB_COM_CREATE SMB_COM_CREATE_NEW SMB_COM_CREATE_DIRECTORY SMB_COM_DELETE SMB_COM_DELETE_DIRECTORY SMB_COM_FIND SMB_COM_FIND_UNIQUE SMB_COM_COPY SMB_COM_RENAME SMB_COM_NT_RENAME SMB_COM_CHECK_DIRECTORY SMB_COM_QUERY_INFORMATION SMB_COM_SET_INFORMATION SMB_COM_GET_PRINT_QUEUE SMB_COM_OPEN_PRINT_FILE SMB_COM_NO_ANDX_COMMAND SMB_COM_TRANSACTION 4.1.4.1 Errors ERRDOS/ERRnomem ERRDOS/ERRbadpath ERRDOS/ERRinvdevice ERRSRV/ERRaccess ERRSRV/ERRbadpw Heizer, et al expires December 1996 [Page 77] INTERNET-DRAFT CIFS/1.0 June 1996 ERRSRV/ERRinvnetname 4.1.5 TREE_DISCONNECT: Tree Disconnect This message informs the server that the client no longer wishes to access the resource connected to with a prior SMB_COM_TREE_CONNECT or SMB_COM_TREE_CONNECT_ANDX. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 The resource sharing connection identified by Tid in the SMB header is logically disconnected from the server. Tid is invalidated; it will not be recognized if used by the client for subsequent requests. All locks, open files, etc. created on behalf of Tid are released. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 4.1.5.1 Errors ERRSRV/invnid ERRSRV/baduid 4.1.6 TRANS2_QUERY_FS_INFORMATION: Get File System Information This transaction requests information about a filesystem on the server. Client Request Value ================================== ================================= Heizer, et al expires December 1996 [Page 78] INTERNET-DRAFT CIFS/1.0 June 1996 WordCount; 15 TotalParameterCount; 2 or 4 MaxSetupCount; 0 SetupCount; 1 or 2 Setup[0]; TRANS2_QUERY_FS_INFORMATION Parameter Block Encoding Description ================================== ================================= USHORT Information Level; Level of information requested The filesystem is identified by Tid in the SMB header. MaxDataCount in the transaction request must be large enough to accommodate the response. Heizer, et al expires December 1996 [Page 79] INTERNET-DRAFT CIFS/1.0 June 1996 The encoding of the response parameter block depends on the InformationLevel requested. Information levels whose values are greater than 0x102 are mapped to corresponding calls to NtQueryVolumeInformationFile calls by the server. The two levels below 0x102 are described below. The requested information is placed in the Data portion of the transaction response. InformationLevel Value NtQueryVolumeInformationFile equivalent ============================= ====== ============================= SMB_INFO_ALLOCATION 1 SMB_INFO_VOLUME 2 SMB_QUERY_FS_VOLUME_INFO 0x102 FileFsVolumeInformation SMB_QUERY_FS_SIZE_INFO 0x103 FileFsSizeInformation SMB_QUERY_FS_DEVICE_INFO 0x104 FileFsDeviceInformation SMB_QUERY_FS_ATTRIBUTE_INFO 0x105 FileFsAttributeInformation The following sections describe the InformationLevel dependent encoding of the data part of the transaction response for the non-NT-equivalent information levels. Heizer, et al expires December 1996 [Page 80] INTERNET-DRAFT CIFS/1.0 June 1996 4.1.6.1 SMB_INFO_ALLOCATION Data Block Encoding Description =================== ================================================ ULONG idFileSystem; File system identifier. NT server always returns 0 ULONG cSectorUnit; Number of sectors per allocation unit ULONG cUnit; Total number of allocation units ULONG cUnitAvail; Total number of available allocation units USHORT cbSector; Number of bytes per sector 4.1.6.2 SMB_INFO_VOLUME Data Block Encoding Description =================== ================================================ ULONG ulVsn; Volume serial number UCHAR cch; Number of characters in Label STRING Label; The volume label 4.1.6.3 Errors ERRSRV/invnid - TID was invalid ERRSRV/baduid - UID was invalid ERRHRD/ERRnotready - the file system has been removed ERRHRD/ERRdata - disk I/O error ERRSRV/ERRaccess - user does not have the right to perform this operation ERRSRV/ERRinvdevice - resource identified by TID is not a file system Heizer, et al expires December 1996 [Page 81] INTERNET-DRAFT CIFS/1.0 June 1996 4.1.7 ECHO: Ping the Server This request is used to test the connection to the server, and to see if the server is still responding. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT EchoCount; Number of times to echo data back USHORT ByteCount; Count of data bytes; min = 1 UCHAR Buffer[1]; Data to echo Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT SequenceNumber; Sequence number of this echo USHORT ByteCount; Count of data bytes; min = 4 UCHAR Buffer[1]; Echoed data Each response echoes the data sent, though ByteCount may indicate no data If EchoCount is zero, no response is sent. Tid in the SMB header is ignored, so this request may be sent to the server even if there are no valid tree connections to the server. The flow for the ECHO protocol is: Client Request <-> Server Response ================================= ==== ============================ Echo Request (EchoCount == n) -> Heizer, et al expires December 1996 [Page 82] INTERNET-DRAFT CIFS/1.0 June 1996 <- Echo Response 1 <- Echo Response 2 <- Echo Response n If a client is communicating to the server over a connectionless transport, this SMB can be used to ensure there is some activity on the connection as required in the "Connectionless Transports" section elsewhere in this document. 4.1.7.1 Errors ERRSRV/ERRbaduid - UID was invalid ERRSRV/ERRnoaccess - session has not been established ERRSRV/ERRnosupport - ECHO function is not supported 4.1.8 NT_CANCEL: Cancel request This SMB allows a client to cancel a request currently pending at the server. Client Request Description ================================== ================================= UCHAR WordCount; No words are sent (== 0) USHORT ByteCount; No bytes (==0) The Sid, Uid, Pid, Tid, and Mid fields of the SMB are used to locate an pending server request from this session. If a pending request is found, it is "hurried along" which may result in success or failure of the original request. No other response is generated for this SMB. 4.2 File Requests 4.2.1 NT_CREATE_ANDX: Create or Open File ** This command is used to create or open a file or a directory. Heizer, et al expires December 1996 [Page 83] INTERNET-DRAFT CIFS/1.0 June 1996 Client Request Description ================================= ================================== UCHAR WordCount; Count of parameter words = 24 UCHAR AndXCommand; Secondary command; 0xFF = None UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount UCHAR Reserved; Reserved (must be 0) USHORT NameLength; Length of Name[] in bytes ULONG Flags; Create bit set: 0x02 - Request an oplock 0x04 - Request a batch oplock 0x08 - Target of open must be directory ULONG RootDirectoryFid; If non-zero, open is relative to this directory ACCESS_MASK DesiredAccess; access desired LARGE_INTEGER AllocationSize; Initial allocation size ULONG FileAttributes; File attributes for creation ** ULONG ShareAccess; Type of share access ** ULONG CreateDisposition; Action to take if file exists or not ULONG CreateOptions; Options to use if creating a file ULONG ImpersonationLevel; Security QOS information UCHAR SecurityFlags; Security tracking mode flags: 0x1 - SECURITY_CONTEXT_TRACKING 0x2 - SECURITY_EFFECTIVE_ONLY USHORT ByteCount; Length of byte parameters Heizer, et al expires December 1996 [Page 84] INTERNET-DRAFT CIFS/1.0 June 1996 STRING Name[]; File to open or create The FIleAttributes parameter specifies the file attributes and flags for the file. The parameter's value is the sum of allowed attributes and flags. Any combination of the following attributes is acceptable, except all other file attributes override FILE_ATTRIBUTE_NORMAL: FILE_ATTRIBUTE_ARCH The file is an archive file. Applications use this IVE attribute to mark files for backup or removal. FILE_ATTRIBUTE_COMP The file or directory is compressed. For a file, RESSED this means that all of the data in the file is compressed. For a directory, this means that compression is the default for newly created files and subdirectories. FILE_ATTRIBUTE_NORM The file has no other attributes set. This AL attribute is valid only if used alone. FILE_ATTRIBUTE_HIDD The file is hidden. It is not to be included in an EN ordinary directory listing. FILE_ATTRIBUTE_READ The file is read only. Applications can read the ONLY file but cannot write to it or delete it. FILE_ATTRIBUTE_SYST The file is part of or is used exclusively by the EM operating system. Any combination of the following flags is acceptable: FILE_FLAG_WRITE_THROUGH Instructs the operating system to write through any intermediate cache and go directly to the file. The operating system can still cache write operations, but cannot lazily flush them. FILE_FLAG_NO_BUFFERING Instructs the operating system to open the file with no intermediate buffering or caching. This can provide performance gains in some situations. An application must meet certain requirements when working with files opened with FILE_FLAG_NO_BUFFERING: . File access must begin at offsets within the file that are integer multiples of the volume's sector size. Heizer, et al expires December 1996 [Page 85] INTERNET-DRAFT CIFS/1.0 June 1996 . File access must be for numbers of bytes that are integer multiples of the volume's sector size. For example, if the sector size is 512 bytes, an application can request reads and writes of 512, 1024, or 2048 bytes, but not of 335, 981, or 7171 bytes. . Buffer addresses for read and write operations must be aligned on addresses in memory that are integer multiples of the volume's sector size. An application can determine a volume's sector size by calling the GetDiskFreeSpace function. FILE_FLAG_RANDOM_ACCESS Indicates that the file is accessed randomly. Windows uses this flag to optimize file caching. FILE_FLAG_SEQUENTIAL_SCAN Indicates that the file is to be accessed sequentially from beginning to end. Windows uses this flag to optimize file caching. If an application moves the file pointer for random access, optimum caching may not occur; however, correct operation is still guaranteed. Specifying this flag can increase performance for applications that read large files using sequential access. Performance gains can be even more noticeable for applications that read large files mostly sequentially, but occasionally skip over small ranges of bytes. FILE_FLAG_DELETE_ON_CLOSE Indicates that the operating system is to delete the file immediately after all of its handles have been closed.If you use this flag when you call CreateFile, then open the file again, and then close the handle for which you specified FILE_FLAG_DELETE_ON_CLOSE, the file will not be deleted until after you have closed the second and any other handle to the file. FILE_FLAG_BACKUP_SEMANTICS Windows NT only: Indicates that the file is being opened or created for a backup or restore operation. The operating system ensures that the calling process overrides file security checks, provided it has the necessary permission to do so. The relevant permissions are SE_BACKUP_NAME and SE_RESTORE_NAME.A Windows NT application can also set this flag to obtain a handle to a directory. A directory handle can be passed to some Win32 functions in place of a file handle. FILE_FLAG_POSIX_SEMANTICS Indicates that the file is to be accessed according to POSIX rules. This includes allowing multiple files with names, differing only in case, for file systems that support such naming. Use care when using this option Heizer, et al expires December 1996 [Page 86] INTERNET-DRAFT CIFS/1.0 June 1996 because files created with this flag may not be accessible by applications written for MS-DOS, Windows 3.x, or Windows NT. The desiredAccess parameter can have one or more of the following flags: GENERIC_READ Specifies read access to the file. Data can be read from the file and the file pointer can be moved. GENERIC_WRITE Specifies write access to the file. Data can be written to the file and the file pointer can be moved. If neither value is specified, it still allows an application to query attributes without actually accessing the file. The CreateDisposition parameter can contain one of the following values: CREATE_NEW Creates a new file. The function fails if the specified file already exists. CREATE_ALWAYS Creates a new file. The function overwrites the file if it exists. OPEN_EXISTING Opens the file. The function fails if the file does not exist. OPEN_ALWAYS Opens the file, if it exists. If the file does not exist, act like CREATE_NEW. TRUNCATE_EXISTING Opens the file. Once opened, the file is truncated so that its size is zero bytes. The calling process must open the file with at least GENERIC_WRITE access. The function fails if the file does not exist. The ImpersonationLevel parameter can contain one or more of the following values: SECURITY_ANONYMOUS Specifies to impersonate the client at the Anonymous impersonation level. SECURITY_IDENTIFICATION Specifies to impersonate the client at the Identification impersonation level. SECURITY_IMPERSONATION Specifies to impersonate the client at the Impersonation impersonation level. SECURITY_DELEGATION Specifies to impersonate the client at the Delegation impersonation level. Heizer, et al expires December 1996 [Page 87] INTERNET-DRAFT CIFS/1.0 June 1996 The SecurityFlags parameter can have either of the following two flags set: SECURITY_CONTEXT_TRACKIN Specifies that the security tracking mode is G dynamic. If this flag is not specified, Security Tracking Mode is static. SECURITY_EFFECTIVE_ONLY Specifies that only the enabled aspects of the client's security context are available to the server. If you do not specify this flag, all aspects of the client's security context are available. This flag allows the client to limit the groups and privileges that a server can use while impersonating the client. Heizer, et al expires December 1996 [Page 88] INTERNET-DRAFT CIFS/1.0 June 1996 Server Response Description ================================= ================================== UCHAR WordCount; Count of parameter words = 26 UCHAR AndXCommand; Secondary 0xFF = None command; UCHAR AndXReserved; MBZ USHORT AndXOffset; Offset to next command WordCount UCHAR OplockLevel; The oplock level granted USHORT Fid; The file ID ULONG CreateAction; The action taken TIME CreationTime; The time the file was created TIME LastAccessTime; The time the file was accessed TIME LastWriteTime; The time the file was last written TIME ChangeTime; The time the file was last changed ULONG FileAttributes; The file attributes LARGE_INTEGER AllocationSize; The number of byes allocated LARGE_INTEGER EndOfFile; The end of file offset USHORT FileType; USHORT DeviceState; state of IPC device (e.g. pipe) BOOLEAN Directory; TRUE if this is a directory USHORT ByteCount; = 0 The following SMBs may follow SMB_COM_NT_CREATE_ANDX: SMB_COM_READ SMB_COM_READ_ANDX SMB_COM_IOCTL Heizer, et al expires December 1996 [Page 89] INTERNET-DRAFT CIFS/1.0 June 1996 4.2.2 NT_TRANSACT_CREATE: Create or Open File with EAs or SD This command is used to create or open a file or a directory, when EAs or an SD must be applied to the file. Request Parameter Block Encoding Description =================================== ================================ ULONG Flags; Creation flags (see below) ULONG RootDirectoryFid; Optional directory for relative open ACCESS_MASK DesiredAccess; Desired access (NT format) LARGE_INTEGER AllocationSize; The initial allocation size in bytes, if file created ULONG FileAttributes; The file attributes, (NT format) ULONG ShareAccess; The share access (NT format) ULONG CreateDisposition; Action to take if file exists or not (NT format) ULONG CreateOptions; Options for creating a new file (NT format) ULONG SecurityDescriptorLength; Length of SD in bytes ULONG EaLength; Length of EA in bytes ULONG NameLength; Length of name in characters ULONG ImpersonationLevel; Security QOS information (NT format) UCHAR SecurityFlags; Security QOS information (NT format) STRING Name[NameLength]; The name of the file (not NULL terminated) Heizer, et al expires December 1996 [Page 90] INTERNET-DRAFT CIFS/1.0 June 1996 Data Block Encoding Description =================================== ================================ UCHAR SecurityDescriptor[ SecurityDescriptorLength]; UCHAR ExtendedAttributes[EaLength]; Creation Flag Name Value Description ========================== ====== ================================== NT_CREATE_REQUEST_OPLOCK 0x02 Level I oplock requested NT_CREATE_REQUEST_OPBATCH 0x04 Batch oplock requested NT_CREATE_OPEN_TARGET_DIR 0x08 Target for open is a directory Output Parameter Block Encoding Description ================================== ================================== UCHAR OplockLevel; The oplock level granted 0 - No oplock granted 1 - Exclusive oplock granted 2 - Batch oplock granted 3 - Level II oplock granted UCHAR Reserved; USHORT Fid; The file ID ULONG CreateAction; The action taken ULONG EaErrorOffset; Offset of the EA error TIME CreationTime; The time the file was created TIME LastAccessTime; The time the file was accessed Heizer, et al expires December 1996 [Page 91] INTERNET-DRAFT CIFS/1.0 June 1996 TIME LastWriteTime; The time the file was last written TIME ChangeTime; The time the file was last changed ULONG FileAttributes; The file attributes LARGE_INTEGER AllocationSize; The number of byes allocated LARGE_INTEGER EndOfFile; The end of file offset USHORT FileType; USHORT DeviceState; state of IPC device (e.g. pipe) BOOLEAN Directory; TRUE if this is a directory The above parameters are in native NT format. Heizer, et al expires December 1996 [Page 92] INTERNET-DRAFT CIFS/1.0 June 1996 4.2.3 CREATE_TEMPORARY: Create Temporary File The server creates a data file in DIRECTORY relative to TID in the SMB header and assigns a unique name to it. Client Request Server Response ================================== ================================= UCHAR WordCount; Count of parameter words = 3 USHORT reserved; Ignored by the server UTIME CreationTime; New file's creation time stamp USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 STRING DirectoryName[]; Directory name Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Fid; File handle USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 STRING Filename[]; File name FID is the returned handle for future file access. Filename is the name of the file which was created within the requested Directory. It is opened in compatibility mode with read/write access for the client. Support of CreationTime by the server is optional. Heizer, et al expires December 1996 [Page 93] INTERNET-DRAFT CIFS/1.0 June 1996 4.2.4 READ_ANDX: Read Data Client Request Description ================================ =================================== UCHAR WordCount; Count of parameter words = 10 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT Fid; File handle ULONG Offset; Offset in file to begin read USHORT MaxCount; Max number of bytes to return USHORT MinCount; Min number of bytes to return ULONG Reserved; Must be 0 USHORT Remaining; Bytes remaining to satisfy request USHORT ByteCount; Count of data bytes = 0 Heizer, et al expires December 1996 [Page 94] INTERNET-DRAFT CIFS/1.0 June 1996 Large File Client Request Description ================================ =================================== UCHAR WordCount; Count of parameter words = 12 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT Fid; File handle ULONG Offset; Offset in file to begin read USHORT MaxCount; Max number of bytes to return USHORT MinCount; Min number of bytes to return ULONG Reserved; Must be 0 USHORT Remaining; Bytes remaining to satisfy request ULONG OffsetHigh; Upper 32 bits of offset USHORT ByteCount; Count of data bytes = 0 Heizer, et al expires December 1996 [Page 95] INTERNET-DRAFT CIFS/1.0 June 1996 Server Response Description ================================ =================================== UCHAR WordCount; Count of parameter words = 12 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT Remaining; Bytes remaining to be read USHORT DataCompactionMode; USHORT Reserved; Reserved (must be 0) USHORT DataLength; Number of data bytes (min = 0) USHORT DataOffset; Offset (from header start) to data USHORT Reserved[5]; Reserved (must be 0) USHORT ByteCount; Count of data bytes UCHAR Pad[]; UCHAR Data[ DataLength]; Data from resource If the negotiated dialect is NT LM 0.12 or later, the client may use the Large File version of the request. This version allows specification of 64 bit file offsets. If CAP_LARGE_READX was indicated by the server in the negotiate protocol response, the request's MAXCOUNT field may exceed the negotiated buffer size if FID refers to a disk file. The server may arbitrarily elect to return fewer than MAXCOUNT bytes in response. MINCOUNT in the request is valid only if FID refers to a named pipe. MINCOUNT informs the server that at least MINCOUNT bytes should be returned, if possible. REMAINING in the response is valid for pipes only. It is used to return the number of bytes currently available in the pipe excluding the bytes returned in this response. This information can then be used by the client to know when a subsequent (non blocking) read of the pipe may return some data. When a future read request is actually received by the server there may be more or less actual data in the pipe (more data has been written to the pipe or another reader drained it). If the Heizer, et al expires December 1996 [Page 96] INTERNET-DRAFT CIFS/1.0 June 1996 information is currently not available or the request is NOT for a pipe, a -1 value should be returned. The following SMBs may follow SMB_COM_READ_ANDX: SMB_COM_CLOSE 4.2.5 READ_RAW: Read Raw The SMB_COM_READ_RAW protocol is used to maximize the performance of reading a large block of data from the server to the client. This request can be applied to files and named pipes. Client Request Description ================================ =================================== UCHAR WordCount; Count of parameter words = 8 USHORT Fid; File handle ULONG Offset; Offset in file to begin read USHORT MaxCount; Max bytes to return (maximum 65535) USHORT MinCount; Min bytes to return (normally 0) ULONG Timeout; Wait time if named pipe USHORT Reserved; USHORT ByteCount; Count of data bytes = 0 FID identifies the resource being read, and may refer to a disk file or a named pipe. TIMEOUT is the number of milliseconds to wait for completion FID refers to a named pipe. When the client issues this request, the client must guarantee that there is (and will be) no other request to the server for the duration of the SMB_COM_READ_RAW. The server will respond, in one send, with the raw data being read. Thus the client is able to request up to 65,535 bytes of data and receive it directly into the user's buffer, since the server response has no header or trailer. Note that the amount of data requested is expected to be larger than the negotiated buffer size for this protocol. Heizer, et al expires December 1996 [Page 97] INTERNET-DRAFT CIFS/1.0 June 1996 The reason that no other requests can be active on the client's connection to the server for the duration of the request is that if other receives are present, there is normally no way to guarantee that the data will be received into the user space, rather the data may fill one (or more) of the other buffers. The number of bytes actually returned is determined by the length of the message the client receives as reported by the transport layer. If the request is to read more bytes than are present in the file, the read response will be of the length actually read from the file. If none of the requested bytes exist (EOF) or an error occurs on the read, the server responds with a zero byte send. Upon receipt of a zero length response, the client should send a different type of request to the server. The response to that read will then tell the client that EOF was hit or identify the error condition. The number of bytes returned may be less than the number requested only if a read specifies bytes beyond the current file size. In this case only the bytes that exist are returned. A read completely beyond the end of file results in a response of zero length. If the number of bytes returned is less than the number of bytes requested, this indicates end of file (if reading other than a standard blocked disk file, only ZERO bytes returned indicates end of file). The transport layer guarantees delivery of all response bytes to the client. Thus no SMB level confirmation protocol is required. If an error should occur at the clients end, all bytes must be received and thrown away. There is no need to inform the server of the error. This message was introduced with the LANMAN1.0 SMB dialect. Whether or not this request is supported is returned in the response to SMB_COM_NEGOTIATE. The flow for reading a sequential file using SMB_COM_READ_BOCK_RAW is: Client Request Server Response ============================== ===================================== SMB_COM_OPEN file Success SMB_COM_READ_RAW raw data returned SMB_COM_READ_RAW more raw data returned Heizer, et al expires December 1996 [Page 98] INTERNET-DRAFT CIFS/1.0 June 1996 SMB_COM_READ_RAW short (or 0 length) response returned SMB_COM_READ 0 bytes returned indicating EOF SMB_COM_CLOSE Success SMB_COM_READ_RAW has no way to return errors. Because the response is raw data only, a zero length response indicates EOF, a read error or that the server is temporarily out of large buffers. The client should then retry using a different type of read request. This request will then either return the EOF condition, an error if the read is still failing, or will work if the problem was due to a temporary server condition. If the negotiated dialect is NT LM 0.12 or later, and the response to the SMB_COM_NEGOTIATE SMB has CAP_LARGE_FILES set in the CAPABILITIES field, a new format of the SMB_COM_READ_RAW request is allowed which accommodates very large files having 64 bit offsets. Client Request Description ================================ =================================== UCHAR WordCount; Count of parameter words = 10 USHORT Fid; File handle ULONG Offset; Offset in file to begin read USHORT MaxCount; Max bytes to return (maximum 65535) USHORT MinCount; Min bytes to return (normally 0) ULONG Timeout; Wait time if named pipe USHORT Reserved; ULONG OffsetHigh; Upper 32 bits of offset USHORT ByteCount; Count of data bytes = 0 This form of the request is differentiated from the previous form of the request by the WORDCOUNT field. In this case, the final offset to read Heizer, et al expires December 1996 [Page 99] INTERNET-DRAFT CIFS/1.0 June 1996 from is used by combining OFFSETHIGH and OFFSET, the resulting value can not be negative or the request will be rejected by the server. SMB_COM_READ_RAW can not be used over connectionless transports. Heizer, et al expires December 1996 [Page 100] INTERNET-DRAFT CIFS/1.0 June 1996 4.2.6 WRITE_ANDX: Write Bytes to file or resource Client Request Description =============================== ==================================== UCHAR WordCount; Count of parameter words = 12 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT Fid; File handle ULONG Offset; Offset in file to begin write ULONG Reserved; Must be 0 USHORT WriteMode; Write mode: 0 - write through 1 - return Remaining 2 - use WriteRawNamedPipe (n. pipes) 3 - "this is the start of the msg" USHORT Remaining; Bytes remaining to satisfy request USHORT Reserved; USHORT DataLength; Number of data bytes in buffer (>=0) USHORT DataOffset; Offset to data bytes USHORT ByteCount; Count of data bytes UCHAR Pad[]; Pad to SHORT or LONG UCHAR Data[DataLength]; Data to write Heizer, et al expires December 1996 [Page 101] INTERNET-DRAFT CIFS/1.0 June 1996 Large File Client Request Description =============================== ==================================== UCHAR WordCount; Count of parameter words = 14 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT Fid; File handle ULONG Offset; Offset in file to begin write ULONG Reserved; Must be 0 USHORT WriteMode; Write mode bits: 0 - write through 1 - return Remaining 2 - use WriteRawNamedPipe (n. pipes) 3 - "this is the start of the msg" USHORT Remaining; Bytes remaining to satisfy request USHORT Reserved; USHORT DataLength; Number of data bytes in buffer (>=0) USHORT DataOffset; Offset to data bytes ULONG OffsetHigh; Upper 32 bits of offset USHORT ByteCount; Count of data bytes UCHAR Pad[]; Pad to SHORT or LONG UCHAR Data[DataLength]; Data to write Heizer, et al expires December 1996 [Page 102] INTERNET-DRAFT CIFS/1.0 June 1996 Server Response Description =============================== ==================================== UCHAR WordCount; Count of parameter words = 6 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT Count; Number of bytes written USHORT Remaining; Bytes remaining to be read in pipe ULONG Reserved; USHORT ByteCount; Count of data bytes = 0 A BYTECOUNT of 0 does not truncate the file. Rather a zero length write merely transfers zero bytes of information to the file. A request such as SMB_COM_WRITE must be used to truncate the file. If WRITEMODE has bit0 set in the request and FID refers to a disk file, the response is not sent from the server until the data is on stable storage. If FID refers to a named pipe, it is possible that the client wishes to transfer more data to the named pipe than the negotiated client and server buffer sizes permit. In this case, the data will arrive at the server in multiple SMB_COM_WRITE_ANDX messages. If WRITEMODE BIT2 and BIT3 are set, this is the first SMB of the sequence, and the total number of bytes which will be written are the sum of DATALENGTH and REMAINING. Subsequent SMB_COM_WRITE_ANDX messages having WRITEMODE BIT2 set and possessing the same PID and FID will be gathered up in the server until DATALENGTH + REMAINING bytes have been received, at which time all the data is written to the named pipe in one message. The return field REMAINING is valid only if FID refers to a named pipe, and WRITEMODE has BIT1 set in the request. It is used to return the number of bytes currently available in the pipe. This information can then be used by the client to know when a subsequent (non blocking) read of the pipe may return some data. When the read request is actually received by the server there may be more or less actual data in the pipe (more data has been written to the pipe / device or another reader drained it). Heizer, et al expires December 1996 [Page 103] INTERNET-DRAFT CIFS/1.0 June 1996 If the negotiated dialect is NT LM 0.12 or later, the Large File format of this SMB may be used to access portions of files requiring offsets expressed as 64 bits. The following are the only valid ANDXCOMMAND values for this SMB: SMB_COM_READ SMB_COM_READ_ANDX SMB_COM_LOCK_AND_READ SMB_COM_WRITE_ANDX SMB_COM_CLOSE 4.2.7 WRITE_RAW: Write Raw Bytes The Write Block Raw protocol is used to maximize the performance of writing a large block of data from the client to the server. The Write Block Raw command's scope includes files, Named Pipes, and spooled output (can be used in place COM_WRITE_PRINT_FILE ). Client Request Description ========================== ========================================= UCHAR WordCount; Count of parameter words = 12 USHORT Fid; File handle USHORT Count; Total bytes, including this buffer USHORT Reserved; ULONG Offset; Offset in file to begin write ULONG Timeout; USHORT WriteMode; Write mode: bit 0 - complete write to disk and send final result response bit 1 - return Remaining (pipe/dev) (see WriteAndX for #defines) ULONG Reserved2; USHORT DataLength; Number of data bytes this buffer USHORT DataOffset; Offset (from header start) to data Heizer, et al expires December 1996 [Page 104] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT ByteCount; Count of data bytes UCHAR Pad[]; Pad to SHORT or LONG UCHAR Data[]; Data (# = DataLength) First Server Response Description ============================== ===================================== UCHAR WordCount; Count of parameter words = 1 USHORT Remaining; Bytes remaining to be read if pipe USHORT ByteCount; Count of data bytes = 0 Final Server Response Description ================================== ================================= UCHAR Command (in SMB header) SMB_COM_WRITE_COMPLETE UCHAR WordCount; Count of parameter words = 1 USHORT Count; Total number of bytes written USHORT ByteCount; Count of data bytes = 0 The first response format will be that of the final server response in the case where the server gets an error while writing the data sent along with the request. Thus COUNT is the number of bytes which did get written any time an error is returned. If an error occurs after the first response has been sent allowing the client to send the remaining data, the final response should not be sent unless write through is set. Rather the server should return this "write behind" error on the next access to the FID. The client must guarantee that there is (and will be) no other request on the connection for the duration of this request. The server will Heizer, et al expires December 1996 [Page 105] INTERNET-DRAFT CIFS/1.0 June 1996 reserve enough resources to receive the data and respond with a response SMB as defined above. The client then sends the raw data in one send. Thus the server is able to receive up to 65,535 bytes of data directly into the server buffer. The amount of data transferred is expected to be larger than the negotiated buffer size for this protocol. The reason that no other requests can be active on the connection for the duration of the request is that if other receives are present on the connection, there is normally no way to guarantee that the data will be received into the correct server buffer, rather the data may fill one (or more) of the other buffers. Also if the client is sending other requests on the connection, a request may land in the buffer that the server has allocated for the this SMB's data. Whether or not SMB_COM_WRITE_RAW is supported is returned in the response to SMB_COM_NEGOTIATE. SMB_COM_WRITE_RAW is not supported for connectionless clients. When write through is not specified ((WRITEMODE & 01) == 0) this SMB is assumed to be a form of write behind. The transport layer guarantees delivery of all secondary requests from the client. Thus no "got the data you sent" SMB is needed. If an error should occur at the server end, all bytes must be received and thrown away. If an error occurs while writing data to disk such as disk full, the next access of the file handle (another write, close, read, etc.) will return the fact that the error occurred. If write through is specified ((WRITEMODE & 01) != 0), the server will receive the data, write it to disk and then send a final response indicating the result of the write. The total number of bytes written is also returned in this response in the COUNT field. The flow for the SMB_COM_WRITE_RAW SMB is: client -----> SMB_COM_WRITE_RAW request (optional data) >-------> server client <------------------< OK send (more) data <---------------- server client ----------------------> raw data >----------------------> server client <---< data on disk or error (write through only) <------- server This protocol is set up such that the SMB_COM_WRITE_RAW request may also carry data. This is an optimization in that up to the server's buffer size (MAXCOUNT from SMB_COM_NEGOTIATE response), minus the size of the SMB_COM_WRITE_RAW SMB request, may be sent along with the request. Thus if the server is busy and unable to support the raw write of the remaining data, the data sent along with the request has been delivered and need not be sent again. The server will write any data sent in the request (and wait for it to be on the disk or device if write through is set), prior to sending the response. The specific responses error class ERRSRV, error codes ERRusempx and ERRusestd, indicate that the server is temporarily out of the resources Heizer, et al expires December 1996 [Page 106] INTERNET-DRAFT CIFS/1.0 June 1996 needed to support the raw write of the remaining data, but that any data sent along with the request has been successfully written. The client should then write the remaining data using a different type of SMB write request, or delay and retry using SMB_COM_WRITE_RAW. If a write error occurs writing the initial data, it will be returned and the write raw request is implicitly denied. The return field REMAINING is returned for named pipes only. It is used to return the number of bytes currently available in the pipe. This information can then be used by the client to know when a subsequent (non blocking) read of the pipe may return some data. Of course when the read request is actually received by the server there may be more or less actual data in the pipe (more data has been written to the pipe / device or another reader drained it). If the information is currently not available or the request is NOT for a pipe or the server does not support this feature, a -1 value should be returned. If the negotiated dialect is NT LM 0.12 or later, and the response to the SMB_COM_NEGOTIATE SMB has CAP_LARGE_FILES set in the CAPABILITIES field, an additional request format is allowed which accommodates very large files having 64 bit offsets: Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 14 USHORT Fid; File handle USHORT Count; Total bytes, including this buffer USHORT Reserved; ULONG Offset; Offset in file to begin write ULONG Timeout; USHORT WriteMode; Write mode: bit 0 - complete write to disk and send final result response bit 1 - return Remaining (pipe/dev) ULONG Reserved2; USHORT DataLength; Number of data bytes this buffer Heizer, et al expires December 1996 [Page 107] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT DataOffset; Offset (from header start) to data ULONG OffsetHigh; Upper 32 bits of offset USHORT ByteCount; Count of data bytes UCHAR Pad[]; Pad to SHORT or LONG UCHAR Data[]; Data (# = DataLength) In this case the final offset in the file is formed by combining OFFSETHIGH and OFFSET, the resulting offset must not be negative. 4.2.8 LOCKING_ANDX: Lock or Unlock Byte Ranges SMB_COM_LOCKING_ANDX allows both locking and/or unlocking of file range(s). Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 8 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT Fid; File handle UCHAR LockType; See LockType table below UCHAR OplockLevel; The new oplock level ULONG Timeout; Milliseconds to wait for unlock USHORT NumberOfUnlocks; Num. unlock range structs following USHORT NumberOfLocks; Num. lock range structs following USHORT ByteCount; Count of data bytes Heizer, et al expires December 1996 [Page 108] INTERNET-DRAFT CIFS/1.0 June 1996 LOCKING_ANDX_RANGE Unlocks[]; Unlock ranges LOCKING_ANDX_RANGE Locks[]; Lock ranges LockType Flag Name Value Description ============================ ===== ================================ LOCKING_ANDX_SHARED_LOCK 0x01 Read-only lock LOCKING_ANDX_OPLOCK_RELEASE 0x02 Oplock break notification LOCKING_ANDX_CHANGE_LOCKTYPE 0x04 Change lock type LOCKING_ANDX_CANCEL_LOCK 0x08 Cancel outstanding request LOCKING_ANDX_LARGE_FILES 0x10 Large file locking format LOCKING_ANDX_RANGE Format ===================================================================== USHORT Pid; PID of process "owning" lock ULONG Offset; Offset to bytes to [un]lock ULONG Length; Number of bytes to [un]lock Large File LOCKING_ANDX_RANGE Format ===================================================================== USHORT Pid; PID of process "owning" lock USHORT Pad; Pad to DWORD align (mbz) ULONG OffsetHigh; Offset to bytes to [un]lock (high) Heizer, et al expires December 1996 [Page 109] INTERNET-DRAFT CIFS/1.0 June 1996 ULONG OffsetLow; Offset to bytes to [un]lock (low) ULONG LengthHigh; Number of bytes to [un]lock (high) ULONG LengthLow; Number of bytes to [un]lock (low) Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 2 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT ByteCount; Count of data bytes = 0 Locking is a simple mechanism for excluding other processes read/write access to regions of a file. The locked regions can be anywhere in the logical file. Locking beyond end-of-file is permitted. Any process using the FID specified in this request's FID has access to the locked bytes, other processes will be denied the locking of the same bytes. The proper method for using locks is not to rely on being denied read or write access on any of the read/write protocols but rather to attempt the locking protocol and proceed with the read/write only if the locks succeeded. Locking a range of bytes will fail if any subranges or overlapping ranges are locked. In other words, if any of the specified bytes are already locked, the lock will fail. If NUMBEROFUNLOCKS is non-zero, the UNLOCKS vector contains NUMBEROFUNLOCKS elements. Each element requests that a lock at OFFSET of LENGTH be released. If NUMBEROFLOCKS is nonzero, the LOCKS vector contains NUMBEROFLOCKS elements. Each element requests the acquisition of a lock at OFFSET of LENGTH. TIMEOUT is the maximum amount of time to wait for the byte range(s) specified to become unlocked. A timeout value of 0 indicates that the Heizer, et al expires December 1996 [Page 110] INTERNET-DRAFT CIFS/1.0 June 1996 server should fail immediately if any lock range specified is locked. A timeout value of -1 indicates that the server should wait as long as it takes for each byte range specified to become unlocked so that it may be again locked by this protocol. Any other value of smb_timeout specifies the maximum number of milliseconds to wait for all lock range(s) specified to become available. If any of the lock ranges timeout because of the area to be locked is already locked (or the lock fails), the other ranges in the protocol request which were successfully locked as a result of this protocol will be unlocked (either all requested ranges will be locked when this protocol returns to the client or none). If LOCKTYPE has the LOCKING_ANDX_SHARED_LOCK flag set, the lock is specified as a shared lock. Locks for both read and write (where LOCKING_ANDX_SHARED_LOCK is clear) should be prohibited, but other shared locks should be permitted. If shared locks can not be supported by a server, the server should map the lock to a lock for both read and write. Closing a file with locks still in force causes the locks to be released in no defined order. If LOCKTYPE has the LOCKING_ANDX_LARGE_FILES flag set and if the negotiated protocol is NT LM 0.12 or later, then the Locks and Unlocks vectors are in the Large File LOCKING_ANDX_RANGE format. This allows specification of 64 bit offsets for very large files. If the one and only member of the LOCKS vector has the LOCKING_ANDX_CANCEL_LOCK flag set in the LOCKTYPE field, the client is requesting the server to cancel a previously requested, but not yet responded to, lock. If LockType has the LOCKING_ANDX_CHANGE_LOCKTYPE flag set, the client is requesting that the server atomically change the lock type from a shared lock to an exclusive lock or vice versa. If the server can not do this in an atomic fashion, the server must reject this request. NT and W95 servers do not support this capability. Oplocks are described in the "Opportunistic Locks" section elsewhere in this document. A client requests an oplock by setting the appropriate bit in the SMB_COM_OPEN_ANDX request when the file is being opened in a mode which is not exclusive. The server responds by setting the appropriate bit in the response SMB indicating whether or not the oplock was granted. By granting the oplock, the server tells the client the file is currently only being used by this one client process at the current time. The client can therefore safely do read ahead and write behind as well as local caching of file locks knowing that the file will not be accessed/changed in any way by another process while the oplock is in effect. The client will be notified when any other process attempts to open or modify the oplocked file. When another user attempts to open or otherwise modify the file which a client has oplocked, the server delays the second attempt and notifies Heizer, et al expires December 1996 [Page 111] INTERNET-DRAFT CIFS/1.0 June 1996 the client via an SMB_LOCKING_ANDX SMB asynchronously sent from the server to the client. This message has the LOCKING_ANDX_OPLOCK_RELEASE flag set indicating to the client that the oplock is being broken. OPLOCKLEVEL indicates the type of oplock the client now owns. If OPLOCKLEVEL is 0, the client possesses no oplocks on the file at all, if OPLOCKLEVEL is 1 the client possesses a Level II oplock. The client is expected to flush any dirty buffers to the server, submit any file locks and respond to the server with either an SMB_LOCKING_ANDX SMB having the LOCKING_ANDX_OPLOCK_RELEASE flag set, or with a file close if the file is no longer in use by the client. If the client sends an SMB_LOCKING_ANDX SMB with the LOCKING_ANDX_OPLOCK_RELEASE flag set and NUMBEROFLOCKS is zero, the server does not send a response. Since a close being sent to the server and break oplock notification from the server could cross on the wire, if the client gets an oplock notification on a file which it does not have open, that notification should be ignored. Due to timing, the client could get an "oplock broken" notification in a user's data buffer as a result of this notification crossing on the wire with a SMB_COM_READ_RAW request. The client must detect this (use length of msg, "FFSMB", MID of -1 and COMMAND of SMB_COM_LOCKING_ANDX) and honor the "oplock broken" notification as usual. The server must also note on receipt of an SMB_COM_READ_RAW request that there is an outstanding (unanswered) "oplock broken" notification to the client and return a zero length response denoting failure of the read raw request. The client should (after responding to the "oplock broken" notification), use a standard read protocol to redo the read request. This allows a file to actually contain data matching an "oplock broken" notification and still be read correctly. The entire message sent and received including the optional second protocol must fit in the negotiated maximum transfer size. The following are the only valid SMB commands for ANDXCOMMAND for SMB_COM_LOCKING_ANDX: SMB_COM_READ SMB_COM_READ_ANDX SMB_COM_WRITE SMB_COM_WRITE_ANDX SMB_COM_FLUSH 4.2.9 SEEK: Seek in File The seek message is sent to set the current file pointer for FID. Client Request Description ================================== ================================= Heizer, et al expires December 1996 [Page 112] INTERNET-DRAFT CIFS/1.0 June 1996 UCHAR WordCount; Count of parameter words = 4 USHORT Fid; File handle USHORT Mode; Seek mode: 0 = from start of file 1 = from current position 2 = from end of file LONG Offset; Relative offset USHORT ByteCount; Count of data bytes = 0 The starting point of the seek is set by MODE: 0 seek from start of file 1 seek from current file pointer 2 seek from end of file The "current position" reflects the offset plus data length specified in the previous read, write or seek request, and the pointer set by this command will be replaced by the offset specified in the next read, write or seek command. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 2 ULONG Offset; Offset from start of file USHORT ByteCount; Count of data bytes = 0 The response returns the new file pointer in OFFSET which is expressed as the offset from the start of the file, and may be beyond the current end of file. An attempt to seek to before the start of file sets the current file pointer to start of the file. This request should generally only be issued by clients wishing to find the size of a file, since all read and write requests include the read Heizer, et al expires December 1996 [Page 113] INTERNET-DRAFT CIFS/1.0 June 1996 or write file position as part of the SMB. This request is inappropriate for very large files, as the offsets specified are only 32 bits. A seek which results in an Offset which can not be expressed in 32 bits returns the least significant . 4.2.10 FLUSH: Flush File The flush SMB is sent to ensure all data and allocation information for the corresponding file has been written to stable storage. When the FID has a value -1 (hex FFFF) the server performs a flush for all file handles associated with the client and PID. The response is not sent until the writes are complete. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Fid; File handle USHORT ByteCount; Count of data bytes = 0 This client request is probably expensive to perform at the server, since the server's operating system is generally scheduling disk writes is a way which is optimal for the system's read and write activity integrated over the entire population of clients. This message from a client "interferes" with the server's ability to optimally schedule the disk activity; clients are discouraged from overuse of this SMB request. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 4.2.11 CLOSE: Close File The close message is sent to invalidate a file handle for the requesting process. All locks or other resources held by the requesting process on the file should be released by the server. The requesting process can no longer use FID for further file access requests. Heizer, et al expires December 1996 [Page 114] INTERNET-DRAFT CIFS/1.0 June 1996 Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 3 USHORT Fid; File handle UTIME LastWriteTime Time of last write USHORT ByteCount; Count of data bytes = 0 If LASTWRITETIME and LASTWRITEDATE are 0, the server should allow its local operating system to set the file's times. Otherwise, the server should set the time to the values requested. Failure to set the times, even if requested by the client in the request message, should not result in an error response from the server. If FID refers to a print spool file, the file should be spooled to the printer at this time. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 4.2.12 DELETE: Delete File The delete file message is sent to delete a data file. The appropriate TID and additional pathname are passed. Read only files may not be deleted, the read-only attribute must be reset prior to file deletion. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 Heizer, et al expires December 1996 [Page 115] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT SearchAttributes; USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 STRING FileName[]; File name Multiple files may be deleted in response to a single request as SMB_COM_DELETE supports wildcards SEARCHATTRIBUTES indicates the attributes that the target file(s) must have. If the attribute is zero then only normal files are deleted. If the system file or hidden attributes are specified then the delete is inclusive -both the specified type(s) of files and normal files are deleted. Attributes are described in the "Attribute Encoding" section of this document. If BIT0 of the FLAGS2 field of the SMB header is set, a pattern is passed in, and the file has a long name, then the passed pattern much match the long file name for the delete to succeed. If BIT0 is clear, a pattern is passed in, and the file has a long name, then the passed pattern must match the file's short name for the deletion to succeed. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 4.2.13 RENAME: Rename File The rename file message is sent to change the name of a file. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT SearchAttributes; Target file attributes Heizer, et al expires December 1996 [Page 116] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT ByteCount; Count of data bytes; min = 4 UCHAR BufferFormat1; 0x04 STRING OldFileName[]; Old file name UCHAR BufferFormat2; 0x04 STRING NewFileName[]; New file name Files OldFileName must exist and NewFileName must not. Both pathnames must be relative to the TID specified in the request. Open files may be renamed. Multiple files may be renamed in response to a single request as Rename File supports wildcards in the file name (last component of the pathname). SearchAttributes indicates the attributes that the target file(s) must have. If SearchAttributes is zero then only normal files are renamed. If the system file or hidden attributes are specified then the rename is inclusive -both the specified type(s) of files and normal files are renamed. The encoding of SearchAttributes is described in the "Attribute Encoding" section of this document. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 Heizer, et al expires December 1996 [Page 117] INTERNET-DRAFT CIFS/1.0 June 1996 4.2.14 MOVE: Rename File The source file is copied to the destination and the source is subsequently deleted. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 3 USHORT Tid2; Second (target) file id USHORT OpenFunction; what to do if target file exists USHORT Flags; Flags to control move operations: 0 - target must be a file 1 - target must be a directory 2 - reserved (must be 0) 3 - reserved (must be 0) 4 - verify all writes USHORT ByteCount; Count of data bytes; min = 2 UCHAR Format1; 0x04 STRING OldFileName[]; Old file name UCHAR FormatNew; 0x04 STRING NewFileName[]; New file name OldFileName is copied to NewFileName, then OldFileName is deleted. Both OldFileName and NewFileName must refer to paths on the same server. NewFileName can refer to either a file or a directory. All file components except the last must exist; directories will not be created. NewFileName can be required to be a file or a directory by the Flags field. The TID in the header is associated with the source while TID2 is associated with the destination. These fields may contain the same or differing valid values. TID2 can be set to -1 indicating that this is to Heizer, et al expires December 1996 [Page 118] INTERNET-DRAFT CIFS/1.0 June 1996 be the same TID as in the SMB header. This allows use of the move protocol with SMB_TREE_CONNECT_ANDX. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Count; Number of files moved USHORT ByteCount; Count of data bytes; min = 0 UCHAR ErrorFileFormat; 0x04 (only if error) STRING ErrorFileName[]; Pathname of file where error occurred The source path must refer to an existing file or files. Wildcards are permitted. Source files specified by wildcards are processed until an error is encountered. If an error is encountered, the expanded name of the file is returned in ErrorFileName. Wildcards are not permitted in NEWFILENAME. OpenFunction controls what should happen if the destination file exists. If (OpenFunction & 0x30) == 0, the operation should fail if the destination exists. If (OpenFunction & 0x30) == 0x20, the destination file should be overwritten. 4.2.15 COPY: Copy File Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 3 USHORT Tid2; Second (target) path TID USHORT OpenFunction; What to do if target file exists USHORT Flags; Flags to control copy operation: bit 0 - target must be a file Heizer, et al expires December 1996 [Page 119] INTERNET-DRAFT CIFS/1.0 June 1996 bit 1 - target must be a dir. bit 2 - copy target mode: 0 = binary, 1 = ASCII bit 3 - copy source mode: 0 = binary, 1 = ASCII bit 4 - verify all writes bit 5 - tree copy USHORT ByteCount; Count of data bytes; min = 2 UCHAR SourceFileNameFormat; 0x04 STRING SourceFileName; Pathname of source file UCHAR TargetFileNameFormat; 0x04 STRING TargetFileName; Pathname of target file The file at SourceName is copied to TargetFileName, both of which must refer to paths on the same server. The TID in the header is associated with the source while TID2 is associated with the destination. These fields may contain the same or differing valid values. TID2 can be set to -1 indicating that this is to be the same TID as in the SMB header. This allows use of the move protocol with SMB_TREE_CONNECT_ANDX. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Count; Number of files copied USHORT ByteCount; Count of data bytes; min = 0 UCHAR ErrorFileFormat; 0x04 (only if error) STRING ErrorFileName; Heizer, et al expires December 1996 [Page 120] INTERNET-DRAFT CIFS/1.0 June 1996 The source path must refer to an existing file or files. Wildcards are permitted. Source files specified by wildcards are processed until an error is encountered. If an error is encountered, the expanded name of the file is returned in ErrorFileName. Wildcards are not permitted in TargetFileName. TargetFileName can refer to either a file or a direc- tory. The destination can be required to be a file or a directory by the bits in FLAGS. If neither BIT0 nor BIT1 are set, the destination may be either a file or a directory. Flags also controls the copy mode. In a binary copy for the source, the copy stops the first time an EOF (control-Z) is encountered. In a binary copy for the target, the server must make sure that there is exactly one EOF in the target file and that it is the last character of the file. If the destination is a file and the source contains wildcards, the destination file will either be truncated or appended to at the start of the operation depending on bits in OpenFunction (see section 3.7). Subsequent files will then be appended to the file. If the negotiated dialect is LM1.2X002 or later, BIT5 of Flags is used to specify a tree copy on the remote server. When this option is selected the destination must not be an existing file and the source mode must be binary. A request with BIT5 set and either BIT0 or BIT3 set is therefore an error. When the tree copy mode is selected, the Count field in the server response is undefined. Heizer, et al expires December 1996 [Page 121] INTERNET-DRAFT CIFS/1.0 June 1996 4.2.16 TRANS2_QUERY_PATH_INFORMATION: Get File Attributes given Path This request is used to get information about a specific file or subdirectory. Client Request Value ========================== ========================================= WordCount 15 MaxSetupCount 0 SetupCount 1 Setup[0] TRANS2_QUERY_PATH_INFORMATION Parameter Block Encoding Description ========================== ========================================= USHORT InformationLevel; Level of information requested ULONG Reserved; Must be zero STRING FileName; File or directory name The following InformationLevels may be requested: Information Level Value NtQueryInformationFile Equivalent ================================ ===== ============================ SMB_INFO_STANDARD 1 SMB_INFO_QUERY_EA_SIZE 2 SMB_INFO_QUERY_EAS_FROM_LIST 3 Heizer, et al expires December 1996 [Page 122] INTERNET-DRAFT CIFS/1.0 June 1996 SMB_INFO_QUERY_ALL_EAS 4 SMB_INFO_IS_NAME_VALID 6 SMB_QUERY_FILE_BASIC_INFO 0x101 FileBasicInformation SMB_QUERY_FILE_STANDARD_INFO 0x102 FileStandardInformation SMB_QUERY_FILE_EA_INFO 0x103 FileEaInformation SMB_QUERY_FILE_NAME_INFO 0x104 FileNameInformation SMB_QUERY_FILE_ALL_INFO 0x107 FileAllInformation SMB_QUERY_FILE_ALT_NAME_INFO 0x108 FileAlternateNameInformation SMB_QUERY_FILE_STREAM_INFO 0x109 FileStreamInformation SMB_QUERY_FILE_COMPRESSION_INFO 0x10B FileCompressionInformation Information levels whose values are greater than 0x101 are mapped to corresponding calls to NtQueryInformationFile calls by the server. The five levels below 0x101 are described below. The requested information is placed in the Data portion of the transaction response. For the NT equivalent responses, the transaction response has 1 parameter word which should be ignored by the client. 4.2.16.1 SMB_INFO_STANDARD & SMB_INFO_QUERY_EA_SIZE Data Block Encoding Description =============================== ==================================== SMB_DATE CreationDate; Date when file was created SMB_TIME CreationTime; Time when file was created SMB_DATE LastAccessDate; Date of last file access SMB_TIME LastAccessTime; Time of last file access SMB_DATE LastWriteDate; Date of last write to the file SMB_TIME LastWriteTime; Time of last write to the file ULONG DataSize; File Size Heizer, et al expires December 1996 [Page 123] INTERNET-DRAFT CIFS/1.0 June 1996 ULONG AllocationSize; Size of filesystem allocation unit USHORT Attributes; File Attributes ULONG EaSize; Size of file's EA information (SMB_INFO_QUERY_EA_SIZE) 4.2.16.2 SMB_INFO_QUERY_EAS_FROM_LIST & SMB_INFO_QUERY_ALL_EAS Response Field Value ==================== =============================================== MaxDataCount Length of FEAlist found (minimum value is 4) Parameter Block Description Encoding ==================== =============================================== USHORT EaErrorOffset Offset into EAList of EA error Data Block Encoding Description ==================== =============================================== ULONG ListLength; Length of the remaining data UCHAR EaList[] The extended attributes list 4.2.16.3 SMB_INFO_IS_NAME_VALID This requests checks to see if the name of the file contained in the request's Data field has a valid path syntax. No parameters or data are returned on this information request. An error is returned if the syntax Heizer, et al expires December 1996 [Page 124] INTERNET-DRAFT CIFS/1.0 June 1996 of the name is incorrect. SUCCESS indicates the server accepts the path syntax, but it does not ensure the file or directory actually exists. 4.2.16.4 SMB_QUERY_FILE_BASIC_INFO typedef struct { TIME CreationTime; TIME LastAccessTime; TIME LastWriteTime; TIME ChangeTime; ULONG FileAttributes; } FILE_BASIC_INFORMATION; 4.2.16.5 SMB_QUERY_FILE_STANDARD_INFO typedef struct { LARGE_INTEGER AllocationSize; LARGE_INTEGER EndOfFile; ULONG NumberOfLinks; BOOLEAN DeletePending; BOOLEAN Directory; } FILE_STANDARD_INFORMATION; 4.2.16.6 SMB_QUERY_FILE_EA_INFO typedef struct { ULONG EaSize; } FILE_EA_INFORMATION; 4.2.16.7 SMB_QUERY_FILE_NAME_INFO typedef struct { ULONG FileNameLength; WCHAR FileName[1]; } FILE_NAME_INFORMATION; 4.2.16.8 SMB_QUERY_FILE_ALL_INFO typedef struct { LARGE_INTEGER IndexNumber; } FILE_INTERNAL_INFORMATION; typedef ULONG ACCESS_MASK; The ACCESS_MASK structure is one 32 bit value containing standard, specific, and generic rights. These rights are used in access-control Heizer, et al expires December 1996 [Page 125] INTERNET-DRAFT CIFS/1.0 June 1996 entries (ACEs) and are the primary means of specifying the requested or granted access to an object. The bits in this value are allocated as follows: Bits Meaning 0 Specific rights. Contains the access mask specific to the through object type associated with the mask. 15 16 through and can be a combination of the following predefined flags: Standard rights. Contains the object's standard access rights 23 Bit Flag Meaning 16 DELETE Delete access 17 READ_CONTROL Read access to the owner, group, and discretionary access-control list (ACL) of the security descriptor 18 WRITE_DAC Write access to the discretionary access- control list (ACL) 19 WRITE_OWNER Write access to owner 20 SYNCHRONIZE Windows NT: Synchronize access Bits Meaning 24 Access system security (ACCESS_SYSTEM_SECURITY). This flag is not a typical access type. It is used to indicate access to a system ACL. This type of access requires the calling process to have a specific privilege. 25 Maximum allowed (MAXIMUM_ALLOWED) 26 Reserved through 27 28 Generic all (GENERIC_ALL) 29 Generic execute (GENERIC_EXECUTE) Heizer, et al expires December 1996 [Page 126] INTERNET-DRAFT CIFS/1.0 June 1996 30 Generic write (GENERIC_WRITE) 31 Generic read (GENERIC_READ) typedef struct { ACCESS_MASK AccessFlags; } FILE_ACCESS_INFORMATION; typedef struct { LARGE_INTEGER CurrentByteOffset; } FILE_POSITION_INFORMATION; typedef struct { ULONG Mode; } FILE_MODE_INFORMATION; typedef struct { ULONG AlignmentRequirement; } FILE_ALIGNMENT_INFORMATION; typedef struct _FILE_ALL_INFORMATION { FILE_BASIC_INFORMATION BasicInformation; FILE_STANDARD_INFORMATION StandardInformation; FILE_INTERNAL_INFORMATION InternalInformation; FILE_EA_INFORMATION EaInformation; FILE_ACCESS_INFORMATION AccessInformation; FILE_POSITION_INFORMATION PositionInformation; FILE_MODE_INFORMATION ModeInformation; FILE_ALIGNMENT_INFORMATION AlignmentInformation; FILE_NAME_INFORMATION NameInformation; } FILE_ALL_INFORMATION; 4.2.16.9 SMB_QUERY_FILE_ALT_NAME_INFO This infornation level returns a FILE_NAME_INFORMATION structure. Heizer, et al expires December 1996 [Page 127] INTERNET-DRAFT CIFS/1.0 June 1996 4.2.16.10 SMB_QUERY_FILE_STREAM_INFO typedef struct { ULONG NextEntryOffset; ULONG StreamNameLength; LARGE_INTEGER StreamSize; LARGE_INTEGER StreamAllocationSize; WCHAR StreamName[1]; } FILE_STREAM_INFORMATION; 4.2.16.11 SMB_QUERY_FILE_COMPRESSION_INFO typedef struct { LARGE_INTEGER CompressedFileSize; USHORT CompressionFormat; UCHAR CompressionUnitShift; UCHAR ChunkShift; UCHAR ClusterShift; UCHAR Reserved[3]; } FILE_COMPRESSION_INFORMATION; Heizer, et al expires December 1996 [Page 128] INTERNET-DRAFT CIFS/1.0 June 1996 4.2.17 TRANS2_SET_PATH_INFORMATION: Set File Attributes given Path This request is used to set information about a specific file or subdirectory. Client Request Value ========================== ========================================= WordCount 15 MaxSetupCount 0 SetupCount 1 Setup[0] TRANS2_SET_PATH_INFORMATION Parameter Block Encoding Description ========================== ========================================= USHORT InformationLevel; Level of information to set ULONG Reserved; Must be zero STRING FileName; File or directory name The following INFORMATIONLEVELS may be set: Information Level Value ========================== ========================================= SMB_INFO_STANDARD 1 SMB_INFO_QUERY_EA_SIZE 2 SMB_INFO_QUERY_ALL_EAS 4 Heizer, et al expires December 1996 [Page 129] INTERNET-DRAFT CIFS/1.0 June 1996 The response formats are: 4.2.17.1 SMB_INFO_STANDARD & SMB_INFO_QUERY_EA_SIZE Parameter Block Encoding Description ================================== ================================= USHORT Reserved 0 Data Block Encoding Description ================================== ================================= SMB_DATE CreationDate; Date when file was created SMB_TIME CreationTime; Time when file was created SMB_DATE LastAccessDate; Date of last file access SMB_TIME LastAccessTime; Time of last file access SMB_DATE LastWriteDate; Date of last write to the file SMB_TIME LastWriteTime; Time of last write to the file ULONG DataSize; File Size ULONG AllocationSize; Size of filesystem allocation unit USHORT Attributes; File Attributes ULONG EaSize; Size of file's EA information (SMB_INFO_QUERY_EA_SIZE) 4.2.17.2 SMB_INFO_QUERY_ALL_EAS Response Field Value Heizer, et al expires December 1996 [Page 130] INTERNET-DRAFT CIFS/1.0 June 1996 ==================== =============================================== MaxDataCount Length of FEAlist found (minimum value is 4) Parameter Block Description Encoding ==================== =============================================== USHORT EaErrorOffset Offset into EAList of EA error Data Block Encoding Description ==================== =============================================== ULONG ListLength; Length of the remaining data UCHAR EaList[] The extended attributes list 4.2.18 TRANS2_QUERY_FILE_INFORMATION: Get File Attributes Given FID This request is used to get information about a specific file or subdirectory given a handle to it. Client Request Value ========================== ========================================== WordCount 15 MaxSetupCount 0 SetupCount 1 Heizer, et al expires December 1996 [Page 131] INTERNET-DRAFT CIFS/1.0 June 1996 Setup[0] TRANS2_QUERY_FILE_INFORMATION Parameter Block Encoding Description ========================== ========================================== USHORT Fid; Handle of file for request USHORT InformationLevel; Level of information requested The available information levels, as well as the format of the response are identical to TRANS2_QUERY_PATH_INFORMATION. 4.2.19 TRANS2_SET_FILE_INFORMATION: Set File Attributes Given FID This request is used to set information about a specific file or subdirectory given a handle to the file or subdirectory. Client Request Value ========================== ========================================== WordCount 15 MaxSetupCount 0 SetupCount 1 Setup[0] TRANS2_SET_FILE_INFORMATION Parameter Block Encoding Description ========================== ========================================== Heizer, et al expires December 1996 [Page 132] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT Fid; Handle of file for request USHORT InformationLevel; Level of information requested USHORT Reserved; Ignored by the server The following INFORMATIONLEVELS may be set: Information Level Value NtSetFileInformation equiv. ================================ ===== ============================= SMB_INFO_STANDARD 1 SMB_INFO_QUERY_EA_SIZE 2 SMB_SET_FILE_BASIC_INFO 0x101 FileBasicInformation SMB_SET_FILE_DISPOSITION_INFO 0x102 FileDispositionInformation SMB_SET_FILE_ALLOCATION_INFO 0x103 FileAllocationInformation SMB_SET_FILE_END_OF_FILE_INFO 0x104 FileEndOfFileInformation Information levels whose values are greater than 0x100 are mapped to corresponding calls to NtSetInformationFile calls by the server. The two levels below 0x100 are as described in the NT_SET_PATH_INFORMATION transaction. The requested information is placed in the Data portion of the transaction response. For the NT equivalent responses, the transaction response has 1 parameter word which should be ignored by the client. 4.3 Directory Requests 4.3.1 TRANS2_CREATE_DIRECTORY: Create Directory (optional EAs) This requests the server to create a directory relative to TID in the SMB header, optionally assigning extended attributes to it. Heizer, et al expires December 1996 [Page 133] INTERNET-DRAFT CIFS/1.0 June 1996 Client Request Value ========================== ========================================= WordCount 15 MaxSetupCount 0 SetupCount 1 Setup[0] TRANS2_CREATE_DIRECTORY Parameter Block Encoding Description ========================== ========================================= ULONG Reserved; Reserved--must be zero STRING Name[]; Directory name to create UCHAR Data[]; Optional FEAList for the new directory Response Parameter Block Description ========================== ========================================= USHORT EaErrorOffset Offset into FEAList of first error which occurred while setting EAs 4.3.2 DELETE_DIRECTORY: Delete Directory The delete directory message is sent to delete an empty directory. The appropriate TID and additional pathname are passed. The directory must be empty for it to be deleted. Client Request Description Heizer, et al expires December 1996 [Page 134] INTERNET-DRAFT CIFS/1.0 June 1996 ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 STRING DirectoryName[]; Directory name The directory to be deleted cannot be the root of the share specified by TID. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 4.3.3 CHECK_DIRECTORY: Check Directory This SMB is used to verify that a path exists and is a directory. No error is returned if the given path exists and the client has read access to it. Client machines which maintain a concept of a "working directory" will find this useful to verify the validity of a "change working directory" command. Note that the servers do NOT have a concept of working directory for a particular client. The client must always supply full pathnames relative to the TID in the SMB header. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 Heizer, et al expires December 1996 [Page 135] INTERNET-DRAFT CIFS/1.0 June 1996 STRING DirectoryPath[]; Directory path Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 DOS clients, in particular, depend on the SMB_ERR_BAD_PATH return code if the directory is not found. 4.3.4 TRANS2_FIND_FIRST2: Search Directory using Wildcards Client Request Value ================================== ================================== WordCount 15 TotalDataCount Total size of extended attribute list SetupCount 1 Setup[0] TRANS2_FIND_FIRST2 Parameter Block Encoding Description ================================== ================================== USHORT SearchAttributes; USHORT SearchCount; Maximum number of entries to return Heizer, et al expires December 1996 [Page 136] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT Flags; Additional information: Bit 0 - close search after this request Bit 1 - close search if end of search reached Bit 2 - return resume keys for each entry found Bit 3 - continue search from previous ending place Bit 4 - find with backup intent USHORT InformationLevel; ULONG SearchStorageType; STRING FileName; Pattern for the search UCHAR Data[ TotalDataCount ] FEAList if InformationLevel is QUERY_EAS_FROM_LIST Response Parameter Block Description ================================== ================================== USHORT Sid; Search handle USHORT SearchCount; Number of entries returned USHORT EndOfSearch; Was last entry returned? USHORT EaErrorOffset; Offset into EA list if EA error USHORT LastNameOffset; Offset into data to file name of last entry, if server needs it to resume search; else 0 UCHAR Data[ TotalDataCount ] Level dependent info about the matches found in the search Heizer, et al expires December 1996 [Page 137] INTERNET-DRAFT CIFS/1.0 June 1996 This request allows the client to search for the file(s) which match the file specification. The search can be continued if necessary with TRANS2_FIND_NEXT2. There are numerous levels of information which may be obtained for the returned files, the desired level is specified in the InformationLevel field of the request. InformationLevel Name Value ================================= ================================== SMB_INFO_STANDARD 1 SMB_INFO_QUERY_EA_SIZE 2 SMB_INFO_QUERY_EAS_FROM_LIST 3 SMB_FIND_FILE_DIRECTORY_INFO 0x101 SMB_FIND_FILE_FULL_DIRECTORY_INFO 0x102 SMB_FIND_FILE_NAMES_INFO 0x103 SMB_FIND_FILE_BOTH_DIRECTORY_INFO 0x104 Information levels whose values are greater than 0x101 are mapped to corresponding calls to NtQueryInformationFile calls by the server. The three levels below 0x101 are described below. The requested information is placed in the DATA portion of the transaction response. A client which does not support long names can only request SMB_INFO_STANDARD. The following sections detail the data returned for each InformationLevel. Heizer, et al expires December 1996 [Page 138] INTERNET-DRAFT CIFS/1.0 June 1996 4.3.4.1 SMB_INFO_STANDARD Response Field Description ================================ ================================== SMB_DATE CreationDate; Date when file was created SMB_TIME CreationTime; Time when file was created SMB_DATE LastAccessDate; Date of last file access SMB_TIME LastAccessTime; Time of last file access SMB_DATE LastWriteDate; Date of last write to the file SMB_TIME LastWriteTime; Time of last write to the file ULONG DataSize; File Size ULONG AllocationSize; Size of filesystem allocation unit USHORT Attributes; File Attributes UCHAR FileNameLength; Length of filename in bytes STRING FileName; Name of found file 4.3.4.2 SMB_INFO_QUERY_EA_SIZE Response Field Description ================================= ================================== SMB_DATE CreationDate; Date when file was created SMB_TIME CreationTime; Time when file was created SMB_DATE LastAccessDate; Date of last file access SMB_TIME LastAccessTime; Time of last file access SMB_DATE LastWriteDate; Date of last write to the file SMB_TIME LastWriteTime; Time of last write to the file ULONG DataSize; File Size Heizer, et al expires December 1996 [Page 139] INTERNET-DRAFT CIFS/1.0 June 1996 ULONG AllocationSize; Size of filesystem allocation unit USHORT Attributes; File Attributes ULONG EaSize; Size of file's EA information UCHAR FileNameLength; Length of filename in bytes STRING FileName; Name of found file 4.3.4.3 SMB_INFO_QUERY_EAS_FROM_LIST This request returns the same information as SMB_INFO_QUERY_EA_SIZE, but only for files which have an EA list which match the EA information in the DATA part of the request. Heizer, et al expires December 1996 [Page 140] INTERNET-DRAFT CIFS/1.0 June 1996 4.3.4.4 SMB_FIND_FILE_DIRECTORY_INFO Response Field Description ================================= ================================== ULONG NextEntryOffset; Offset from this structure to beginning of next one ULONG FileIndex; LARGE_INTEGER CreationTime; file creation time LARGE_INTEGER LastAccessTime; last access time LARGE_INTEGER LastWriteTime; last write time LARGE_INTEGER ChangeTime; last attribute change time LARGE_INTEGER EndOfFile; file size LARGE_INTEGER AllocationSize; size of filesystem allocation information ULONG FileAttributes; NT style encoding of file attributes ULONG FileNameLength; Length of filename in bytes STRING FileName; Name of the file 4.3.4.5 SMB_FIND_FILE_FULL_DIRECTORY_INFO Response Field Description ================================= ================================== ULONG NextEntryOffset; Offset from this structure to beginning of next one ULONG FileIndex; LARGE_INTEGER CreationTime; file creation time LARGE_INTEGER LastAccessTime; last access time LARGE_INTEGER LastWriteTime; last write time Heizer, et al expires December 1996 [Page 141] INTERNET-DRAFT CIFS/1.0 June 1996 LARGE_INTEGER ChangeTime; last attribute change time LARGE_INTEGER EndOfFile; file size LARGE_INTEGER AllocationSize; size of filesystem allocation information ULONG FileAttributes; NT style encoding of file attributes ULONG FileNameLength; Length of filename in bytes ULONG EaSize; Size of file's extended attributes STRING FileName; Name of the file 4.3.4.6 SMB_FIND_FILE_BOTH_DIRECTORY_INFO Response Field Description ================================= ================================== ULONG NextEntryOffset; Offset from this structure to beginning of next one ULONG FileIndex; LARGE_INTEGER CreationTime; file creation time LARGE_INTEGER LastAccessTime; last access time LARGE_INTEGER LastWriteTime; last write time LARGE_INTEGER ChangeTime; last attribute change time LARGE_INTEGER EndOfFile; file size LARGE_INTEGER AllocationSize; size of filesystem allocation information ULONG FileAttributes; NT style encoding of file attributes ULONG FileNameLength; Length of FileName in bytes ULONG EaSize; Size of file's extended attributes UCHAR ShortNameLength; Length of file's short name in Heizer, et al expires December 1996 [Page 142] INTERNET-DRAFT CIFS/1.0 June 1996 bytes WCHAR ShortName[12]; File's 8.3 conformant name in Unicode STRING FileName; Files full length name 4.3.4.7 SMB_FIND_FILE_NAMES_INFO Response Field Description ================================= ================================== ULONG NextEntryOffset; Offset from this structure to beginning of next one ULONG FileIndex; ULONG FileNameLength; Length of FileName in bytes STRING FileName; Files full length name Heizer, et al expires December 1996 [Page 143] INTERNET-DRAFT CIFS/1.0 June 1996 4.3.5 TRANS2_FIND_NEXT2: Resume Directory Search Using Wildcards This request resumes a search which was begun with a previous TRANS2_FIND_FIRST2 request. Client Request Value ================================== ================================= WordCount 15 SetupCount 1 Setup[0] TRANS2_FIND_NEXT2 Parameter Block Encoding Description ================================== ================================= USHORT Sid; Search handle USHORT SearchCount; Maximum number of entries to return USHORT InformationLevel; Levels described in TRANS2_FIND_FIRST2 request ULONG ResumeKey; Value returned by previous find2 call USHORT Flags; Additional information: bit set- 0 - close search after this request 1 - close search if end of search reached 2 - return resume keys for each entry found 3 - resume/continue from previous ending place Heizer, et al expires December 1996 [Page 144] INTERNET-DRAFT CIFS/1.0 June 1996 4 - find with backup intent STRING FileName; Resume file name SID is the value returned by a previous successful TRANS2_FIND_FIRST2 call. If BIT3 of FLAGS is set, then FileName may be the NULL string, since the search is continued from the previous TRANS2_FIND request. Otherwise, FileName must not be more than 256 characters long. Response Field Description ================================== ================================= USHORT SearchCount; Number of entries returned USHORT EndOfSearch; Was last entry returned? USHORT EaErrorOffset; Offset into EA list if EA error USHORT LastNameOffset; Offset into data to file name of last entry, if server needs it to resume search; else 0 UCHAR Data[TotalDataCount] Level dependent info about the matches found in the search 4.3.6 FIND_CLOSE2: Close Directory Search This SMB closes a search started by the TRANS2_FIND_FIRST2 transaction request. Heizer, et al expires December 1996 [Page 145] INTERNET-DRAFT CIFS/1.0 June 1996 Client Request Description ================================== ================================== UCHAR WordCount; Count of parameter words = 1 USHORT Sid; Find handle USHORT ByteCount; Count of data bytes = 0 Server Response Description ================================== ================================== UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 4.3.7 NT_TRANSACT_NOTIFY_CHANGE: Request Change Notification Client Setup Words Description ================================== ================================= ULONG CompletionFilter; Specifies operation to monitor (NT format) USHORT Fid; Fid of directory to monitor BOOLEAN WatchTree; TRUE = watch all subdirectories too UCHAR Reserved; MBZ This command notifies the client when the directory specified by FID is modified. It also returns the name(s) of the file(s) that changed. The command completes once the directory has been modified based on the supplied CompletionFilter. The command is a "single shot" and therefore needs to be reissued to watch for more directory changes. Heizer, et al expires December 1996 [Page 146] INTERNET-DRAFT CIFS/1.0 June 1996 A directory file must be opened before this command may be used. Once the directory is open, this command may be used to begin watching files and subdirectories in the specified directory for changes. The first time the command is issued, the MaxParameterCount field in the transact header determines the size of the buffer that will be used at the server to buffer directory change information between issuances of the notify change commands. When a change that is in the CompletionFilter is made to the directory, the command completes. The names of the files that have changed since the last time the command was issued are returned to the client. The ParameterCount field of the response indicates the number of bytes that are being returned. If too many files have changed since the last time the command was issued, then zero bytes are returned and an alternate status code is returned in the Status field of the response. The CompletionFilter is a mask created as the sum of any of the following flags: FILE_NOTIFY_CHANGE_FILE_NAME 0x00000001 FILE_NOTIFY_CHANGE_DIR_NAME 0x00000002 FILE_NOTIFY_CHANGE_NAME 0x00000003 FILE_NOTIFY_CHANGE_ATTRIBUTES 0x00000004 FILE_NOTIFY_CHANGE_SIZE 0x00000008 FILE_NOTIFY_CHANGE_LAST_WRITE 0x00000010 FILE_NOTIFY_CHANGE_LAST_ACCESS 0x00000020 FILE_NOTIFY_CHANGE_CREATION 0x00000040 FILE_NOTIFY_CHANGE_EA 0x00000080 FILE_NOTIFY_CHANGE_SECURITY 0x00000100 FILE_NOTIFY_CHANGE_STREAM_NAME 0x00000200 FILE_NOTIFY_CHANGE_STREAM_SIZE 0x00000400 FILE_NOTIFY_CHANGE_STREAM_WRITE 0x00000800 Server Response Description ================================== ================================ Heizer, et al expires December 1996 [Page 147] INTERNET-DRAFT CIFS/1.0 June 1996 == ParameterCount # of bytes of change data Parameters[ ParameterCount ] FILE_NOTIFY_INFORMATION structures The response contains FILE_NOTIFY_INFORMATION structures, as defined below. The NextEntryOffset field of the structure specifies the offset, in bytes, from the start of the current entry to the next entry in the list. If this is the last entry in the list, this field is zero. Each entry in the list must be longword aligned, so NextEntryOffset must be a multiple of four. typedef struct { ULONG NextEntryOffset; ULONG Action; ULONG FileNameLength; WCHAR FileName[1]; } FILE_NOTIFY_INFORMATION; Where Action describes what happened to the file named FileName: FILE_ACTION_ADDED 0x00000001 FILE_ACTION_REMOVED 0x00000002 FILE_ACTION_MODIFIED 0x00000003 FILE_ACTION_RENAMED_OLD_N 0x00000004 AME FILE_ACTION_RENAMED_NEW_N 0x00000005 AME FILE_ACTION_ADDED_STREAM 0x00000006 FILE_ACTION_REMOVED_STREA 0x00000007 M FILE_ACTION_MODIFIED_STRE 0x00000008 AM Heizer, et al expires December 1996 [Page 148] INTERNET-DRAFT CIFS/1.0 June 1996 4.4 DFS Operations 4.4.1 TRANS2_GET_DFS_REFERRAL: Retrieve Distributed Filesystem Referral The client sends this request to ask the server to convert RequestFilename into an alternate name for this file. This request can be sent to the server if the server response to the NEGOTIATE SMB included the CAP_DFS capability. The TID of the request must be IPC$. BIT15 of Flags2 in the SMB header must be set, indicating this is a UNICODE request. Client Request Description ========================== ========================================= WordCount 15 TotalDataCount 0 SetupCount 1 Setup[0] TRANS2_GET_DFS_REFERRAL Parameter Block Encoding Description ========================== ========================================= USHORT MaxReferralLevel Latest referral version number understood WCHAR RequestFileName; DFS name of file for which referral is sought Response Data Block Description ========================== ========================================= USHORT PathConsumed; Number of REQUESTFILENAME bytes client Heizer, et al expires December 1996 [Page 149] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT NumberOfReferrals; Number of referrals contained in this response USHORT Flags; bit0 - The servers in REFERRALS are capable of fielding TRANS2_GET_DFS_REFERRAL. bit1 - The servers in REFERRALS should hold the storage for the requested file. REFERRAL_LIST Referrals[] Set of referrals for this file UNICODESTRINGE Strings Used to hold the strings pointed to by Version 2 Referrals in REFERRALS. The server response is a list of Referrals which inform the client where it should resubmit the request to obtain access to the file. PathConsumed in the response indicates to the client how many characters of RequestFilename have been consumed by the server. When the client chooses one of the referrals to use for file access, the client may need to strip the leading PathConsumed characters from the front of RequestFileName before submitting the name to the target server. Whether or not the pathname should be trimmed is indicated by the individual referral as detailed below. FLAGS indicates how this referral should be treated. If BIT0 is clear, any entity in the REFERRALS list holds the storage for REQUESTFILENAME. If BIT0 is set, any entity in the REFERRALS list has further referral information for REQUESTFILENAME _ a TRANS2_GET_DFS_REFERRAL request should be sent to an entity in the REFERRALS list for further resolution. The format of an individual referral contains version and length information allowing the client to skip referrals it does not understand. MaxReferralLevel indicates to the server the latest version of referral which the client can digest. Since each referral has a uniform element, MAXREFERRALLEVEL is advisory only. Each element in REFERRALS has this envelope: Heizer, et al expires December 1996 [Page 150] INTERNET-DRAFT CIFS/1.0 June 1996 REFERRAL_LIST element ====================================================================== USHORT VersionNumber Version of this referral element USHORT ReferralSize Size of this referral element The following referral element versions are defined: Version 1 Referral Element Format ====================================================================== USHORT ServerType Type of NODE handling referral: 0 - Don't know 1 - SMB Server 2 - Netware Server 3 - Domain USHORT ReferralFlags Flags which describe this referral: 01 - Strip off PATHCONSUMED characters before submitting REQUESTFILENAME to NODE UNICODESTRING Node Name of entity to visit next Heizer, et al expires December 1996 [Page 151] INTERNET-DRAFT CIFS/1.0 June 1996 Version 2 Referral Element Format ====================================================================== USHORT ServerType Type of NODE handling referral: 0 - Don't know 1 - SMB Server 2 - Netware Server 3 - Domain USHORT ReferralFlags Flags which describe this referral: 01 - Strip off PATHCONSUMED characters before submitting REQUESTFILENAME to NODE ULONG Proximity A hint describing the proximity of this server to the client. 0 indicates the closest, higher numbers indicate increasingly "distant" servers. The number is only relevant within the context of the servers listed in THIS particular SMB. ULONG TimeToLive Number of seconds for which the client can cache this referral. USHORT DfsPathOffset Offset, in bytes from the beginning of this referral, of the DFS Path that matched PATHCONSUMED bytes of the REQUESTFILENAME. USHORT DfsAlternatePathOffset Offset, in bytes from the beginning of this referral, of an alternate name (8.3 format) of the DFS Path that matched PATHCONSUMED bytes of the REQUESTFILENAME. Heizer, et al expires December 1996 [Page 152] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT NetworkAddressOffset Offset, in bytes from the beginning of this referral, of the entity to visit next. The SMB protocol imposes no referral selection policy. 4.4.2 TRANS2_REPORT_DFS_INCONSISTENCY: Inform a server about DFS Error As part of the Distributed Name Resolution algorithm, a DFS client may discover a knowledge inconsistency between the referral server (i.e., the server that handed out a referral), and the storage server (i.e., the server to which the client was redirected to by the referral server). When such an inconsistency is discovered, the DFS client optionally sends this SMB to the referral server, allowing the referral server to take corrective action. Client Request Description ================================== ================================== WordCount 15 MaxParameterCount 0 SetupCount 1 Setup[0] TRANS2_REPORT_DFS_INCONSISTENCY Parameter Block Encoding Description ================================== ================================== UNICODESTRING RequestFileName; DFS Name of file for which referral was sought The data part of this request contains the referral element (Version 1 format only) believed to be in error. These are encoded as described in Heizer, et al expires December 1996 [Page 153] INTERNET-DRAFT CIFS/1.0 June 1996 the TRANS2_GET_DFS_REFERRAL response. If the server returns success, the client can resubmit the TRANS2_GET_DFS_REFERRAL request to this server to get a new referral. It is not mandatory for the DFS knowledge to be automatically repaired _ the client must be prepared to receive further errant referrals and must not wind up looping between this request and the TRANS2_GET_DFS_REFERRAL request. BIT15 of FLAGS2 in the SMB header must be set, indicating this is a UNICODE request. 4.5 Print Spooling Operations 4.5.1 OPEN_PRINT_FILE: Create Print Spool file This message is sent to create a new printer file which will be deleted once it has been closed and printed. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 2 USHORT SetupLength; Length of printer setup data USHORT Mode; 0 = Text mode (DOS expands TABs) 1 = Graphics mode USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 STRING IdentifierString[]; Identifier string TID in the SMB header must refer to a printer resource type. SETUPLENGTH is the number of bytes in the first part of the resulting print spool file which contains printer-specific control strings. MODE can have the following values: 0 Text mode. The server may optionally expand tabs to a series of spaces. Heizer, et al expires December 1996 [Page 154] INTERNET-DRAFT CIFS/1.0 June 1996 1 Graphics mode. No conversion of data should be done by the server. IDENTIFIERSTRING can be used by the server to provide some sort of per- client identifying component to the print file. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Fid; File handle USHORT ByteCount; Count of data bytes = 0 FID is the returned handle which may be used by subsequent write and close operations. When the file is finally closed, it will be sent to the spooler and printed. 4.5.2 GET_PRINT_QUEUE: Get Printer Queue Entries This message obtains a list of the elements currently in the print queue on the server. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 2 USHORT MaxCount; Max number of entries to return USHORT StartIndex; First queue entry to return USHORT ByteCount; Count of data bytes = 0 STARTINDEX specifies the first entry in the queue to return. Heizer, et al expires December 1996 [Page 155] INTERNET-DRAFT CIFS/1.0 June 1996 MAXCOUNT specifies the maximum number of entries to return, this may be a positive or negative number. A positive number requests a forward search, a negative number indicates a backward search. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 2 USHORT Count; Number of entries returned USHORT RestartIndex; Index of entry after last returned USHORT ByteCount; Count of data bytes; min = 3 UCHAR BufferFormat; 0x01 -- Data block USHORT DataLength; Length of data UCHAR Data[]; Queue elements COUNT indicates how many entries were actually returned. RESTARTINDEX is the index of the entry following the last entry returned; it may be used as the STARTINDEX in a subsequent request to resume the queue listing. The format of each returned queue element is: Queue Element Member Description ================================ =================================== SMB_DATE FileDate; Date file was queued SMB_TIME FileTime; Time file was queued UCHAR Status; Entry status. One of: 01 = held or stopped 02 = printing 03 = awaiting print Heizer, et al expires December 1996 [Page 156] INTERNET-DRAFT CIFS/1.0 June 1996 04 = in intercept 05 = file had error 06 = printer error 07-FF = reserved USHORT SpoolFileNumber; Assigned by the spooler ULONG SpoolFileSize; Number of bytes in spool file UCHAR Reserved; UCHAR SpoolFileName[16]; Client which created the spool file SMB_COM_GET_PRINT_QUEUE will return less than the requested number of elements only when the top or end of the queue is encountered. Support for this SMB is server optional. In particular, no current Microsoft client software issues this request. 4.6 Miscellaneous Operations 4.6.1 NT_TRANSACT_IOCTL This command allows device and file system control functions to be transferred transparently from client to server. Setup Words Encoding Description =========================== ========================================= ULONG FunctionCode; NT device or file system control code USHORT Fid; Handle for io or fs control. Unless BIT0 of ISFLAGS is set. BOOLEAN IsFsctl; Indicates whether the command is a device control (FALSE) or a file system control (TRUE). UCHAR IsFlags; BIT0 - command is to be applied to share root handle. Share must be a DFS share. Heizer, et al expires December 1996 [Page 157] INTERNET-DRAFT CIFS/1.0 June 1996 Data Block Encoding Description =========================== ========================================= Data[ TotalDataCount ] Passed to the Fsctl or Ioctl Server Response Description ================================== ================================== SetupCount 1 Setup[0] Length of information returned by io or fs control DataCount Length of information returned by io or fs control Data[ DataCount ] The results of the io or fs control 4.6.2 NT_TRANSACT_QUERY_SECURITY_DESC This command allows the client to retrieve the security descriptor on a file. Client Parameter Block Description ================================== ================================= USHORT Fid; FID of target USHORT Reserved; MBZ ULONG SecurityInformation; Fields of descriptor to set Heizer, et al expires December 1996 [Page 158] INTERNET-DRAFT CIFS/1.0 June 1996 NtQuerySecurityObject() is called, requesting SECURITYINFORMATION. The result of the call is returned to the client in the DATA part of the transaction response. 4.6.3 NT_TRANSACT_SET_SECURITY_DESC This command allows the client to change the security descriptor on a file. Client Parameter Block Encoding Description ================================== ================================== USHORT Fid; FID of target USHORT Reserved; MBZ ULONG SecurityInformation; Fields of SD that to set Data Block Encoding Description ================================== ================================== Data[TotalDataCount] Security Descriptor information DATA is passed directly to NtSetSecurityObject(), with SECURITYINFORMATION describing which information to set. The transaction response contains no parameters or data. 5. Obsolescent SMB Requests This section lists the "obsolescent" SMB requests -- ones that are superceded by "best practice" requests, either in function or performance. Clients need not use them to get full function or performance, however, servers do need to support them in order to interoperate with existing clients. Heizer, et al expires December 1996 [Page 159] INTERNET-DRAFT CIFS/1.0 June 1996 5.1 CLOSE_PRINT_FILE: Close and Spool Print Job* This message invalidates the specified file handle and queues the file for printing. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Fid; File handle USHORT ByteCount; Count of data bytes = 0 FID refers to a file previously created with SMB_COM_OPEN_PRINT_FILE. On successful completion of this request, the file is queued for printing by the server. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 Servers which negotiate dialects of LANMAN1.0 and newer allow all the other types of FID closing requests to invalidate the FID and begin spooling. 5.2 CREATE: Create File* This message is sent to create a new data file or truncate an existing data file to length zero, and open the file. The handle returned can be used in subsequent read, write, lock, unlock and close messages. Heizer, et al expires December 1996 [Page 160] INTERNET-DRAFT CIFS/1.0 June 1996 Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 3 USHORT FileAttributes; New file attributes UTIME CreationTime; Time file was created USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 STRING FileName[]; File name FileName is the fully qualified name of the file relative to Tid. FileAttributes are encoded as described in the "File Attribute Encoding" section. Server support of the CreationTime field is optional. Encoding of these fields is discussed in the "Time And Date Encoding" section. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Fid; File handle USHORT ByteCount; Count of data bytes = 0 Clients must have write permission on the file's parent directory in order to create a new file, or write permission on the file itself in order to truncate it. The access permissions granted on a created file will be read/write permission for the creator. Access permissions for truncated files are not modified. The newly created or truncated file is opened in read/write/compatibility mode. Heizer, et al expires December 1996 [Page 161] INTERNET-DRAFT CIFS/1.0 June 1996 5.3 CREATE_DIRECTORY: Create Directory The create directory message is sent to create a new directory. The appropriate TID and additional pathname are passed. The directory must not exist for it to be created. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 STRING DirectoryName[]; Directory name Servers require clients to have at least CREATE permission for the subtree containing the directory in order to create a new directory. The creator's access rights to the new directory are be determined by local policy on the server. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 5.4 CREATE_NEW: Create File* This message is sent to create a new data file or truncate an existing data file to length zero, and open the file. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 3 Heizer, et al expires December 1996 [Page 162] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT FileAttributes; New file attributes UTIME CreationTime; Creation time for created file USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 STRING FileName[]; File name FileAttributes specify the attributes of the newly created file, their encoding is described in the "Attribute Encoding" section of this document. CreationTime is the creation timestamp the file should be given, server support for these is optional. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Fid; File handle USHORT ByteCount; Count of data bytes = 0 The returned FID can be used in subsequent FID-related messages. The access permissions granted on a created file are read/write permission for the creator. Access permissions for truncated files are not modified. The newly created or truncated file is opened in read/write/compatibility mode. Heizer, et al expires December 1996 [Page 163] INTERNET-DRAFT CIFS/1.0 June 1996 5.5 LOCK_AND_READ: Lock and Read Bytes* This request is used to lock and "read ahead" the specified bytes of the file indicated by FID in the SMB header Client Request Description ============================== ===================================== UCHAR WordCount; Count of parameter words = 5 USHORT Fid; File handle USHORT Count; Count of bytes being requested ULONG Offset; Offset in file of first byte to read USHORT Remaining; Estimate of bytes to read if nonzero USHORT ByteCount; Count of data bytes = 0 FID must refer to a disk file. COUNT specifies the requested number of bytes. OFFSET specifies the offset in the file of the first byte to be locked then read. Note that this offset is limited to 32 bits, so this client request is inappropriate for files having 64 bit offsets. REMAINING is advisory. If the value is not zero, then it is taken as an estimate of the total number of bytes that will be read, including those read by this request. This additional information may be used by the server to optimize buffer allocation or read-ahead. REMAINING is not included in the byte range to be locked. Heizer, et al expires December 1996 [Page 164] INTERNET-DRAFT CIFS/1.0 June 1996 Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 5 USHORT Count; Count of bytes actually returned USHORT Reserved [4]; Reserved (must be 0) USHORT ByteCount; Count of data bytes UCHAR BufferFormat; 0x01 -- Data block USHORT DataLength; Length of data BYTECOUNT is the number of bytes actually being returned. BYTECOUNT may be less than the count requested only if a read specifies bytes beyond the current file size. In this case only the bytes that exist are returned. A read completely beyond the end of file results in a response of length zero. This is the only circumstance when a zero length response is generated. A count returned which is less than the count requested is the end of file indicator. As in the core SMB_LOCK_BYTE_RANGE request, if the lock can not be immediately granted an error should be returned to the client. If an error occurs on the lock, the bytes should not be read. If a Read requests more data than can be placed in a message of the maximum-xmit- size for the TID specified, the server will abort the connection to the client. Heizer, et al expires December 1996 [Page 165] INTERNET-DRAFT CIFS/1.0 June 1996 5.6 LOCK_BYTE_RANGE: Lock Bytes* The lock record message is sent to lock the given byte range. More than one non-overlapping byte range may be locked in a given file. Locks prevent attempts to lock, read or write the locked portion of the file by other clients or PIDs. Overlapping locks are not allowed. Offsets beyond the current end of file may be locked. Such locks will not cause allocation of file space. Since OFFSET is a 32 bit quantity, this request is inappropriate for general locking within a very large file. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 5 USHORT Fid; File handle ULONG Count; Count of bytes to lock ULONG Offset; Offset from start of file USHORT ByteCount; Count of data bytes = 0 Locks may only be unlocked by the PID that performed the lock. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 This client request does not wait for the lock to be granted. If the lock can not be immediately granted (within 200-300 ms), the server should return failure to the client Heizer, et al expires December 1996 [Page 166] INTERNET-DRAFT CIFS/1.0 June 1996 5.7 OPEN: Open File* This message is sent to obtain a file handle for a data file. This returned FID is used in subsequent client requests such as read, write, close, etc. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 2 USHORT DesiredAccess; Mode - read/write/share USHORT SearchAttributes; USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 STRING FileName[]; File name FILENAME is the fully qualified file name, relative to the root of the share specified in the TID field of the SMB header. If TID in the SMB header refers to a print share, this SMB creates a new file which will be spooled to the printer when closed. In this case, FILENAME is ignored. SEARCHATTRIBUTES specifies the type of file desired. The encoding is described in the "File Attribute Encoding" section. DESIREDACCESS controls the mode under which the file is opened, and the file will be opened only if the client has the appropriate permissions. The encoding of DESIREDACCESS is discussed in the section entitled "Access Mode Encoding". Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 7 USHORT Fid; File handle USHORT FileAttributes; Attributes of opened file Heizer, et al expires December 1996 [Page 167] INTERNET-DRAFT CIFS/1.0 June 1996 UTIME LastWriteTime; Time file was last written ULONG DataSize; File size USHORT GrantedAccess; Access allowed USHORT ByteCount; Count of data bytes = 0 FID is the handle value which should be used for subsequent file operations. FILEATTRIBUTES specifies the type of file obtained. The encoding is described in the "File Attribute Encoding" section. GRANTEDACCESS indicates the access permissions actually allowed, and may have one of the following values: 0 read-only 1 write-only 2 read/write File Handles (FIDs) are scoped per client. A PID may reference any FID established by itself or any other PID on the client (so far as the server is concerned). The actual accesses allowed through the FID depends on the open and deny modes specified when the file was opened (see below). The MS-DOS compatibility mode of file open provides exclusion at the client level. A file open in compatibility mode may be opened (also in compatibility mode) any number of times for any combination of reading and writing (subject to the user's permissions) by any PID on the same client. If the first client has the file open for writing, then the file may not be opened in any way by any other client. If the first client has the file open only for reading, then other clients may open the file, in compatibility mode, for reading.. The above notwithstanding, if the filename has an extension of .EXE, .DLL, .SYM, or .COM other clients are permitted to open the file regardless of read/write open modes of other compatibility mode opens. However, once multiple clients have the file open for reading, no client is permitted to open the file for writing and no other client may open the file in any mode other than compatibility mode. The other file exclusion modes (Deny read/write, Deny write, Deny read, Deny none) provide exclusion at the file level. A file opened in any "Deny" mode may be opened again only for the accesses allowed by the Deny mode (subject to the user's permissions). This is true regardless of the identity of the second opener -a different client, a PID from the Heizer, et al expires December 1996 [Page 168] INTERNET-DRAFT CIFS/1.0 June 1996 same client, or the PID that already has the file open. For example, if a file is open in "Deny write" mode a second open may only obtain read permission to the file. Although FIDs are available to all PIDs on a client, PIDs other than the owner may not have the full access rights specified in the open mode by the FID's creator. If the open creating the FID specified a deny mode, then any PID using the FID, other than the creating PID, will have only those access rights determined by "anding" the open mode rights and the deny mode rights, i.e., the deny mode is checked on all file accesses. For example, if a file is opened for Read/Write in Deny write mode, then other clients may only read the file and cannot write; if a file is opened for Read in Deny read mode, then the other clients can neither read nor write the file. Heizer, et al expires December 1996 [Page 169] INTERNET-DRAFT CIFS/1.0 June 1996 5.8 OPEN_ANDX: Open File* Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 15 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT Flags; Additional information: bit set- 0 - return additional info 1 - exclusive oplock requested 2 - batch oplock requested USHORT DesiredAccess; File open mode USHORT SearchAttributes; USHORT FileAttributes; UTIME CreationTime; Creation timestamp for file if it gets created USHORT OpenFunction; Action to take if file exists ULONG AllocationSize; Bytes to reserve on create or truncate ULONG Reserved[2]; Must be 0 USHORT ByteCount; Count of data bytes; min = 1 UCHAR BufferFormat 0x04 STRING FileName; Heizer, et al expires December 1996 [Page 170] INTERNET-DRAFT CIFS/1.0 June 1996 Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 15 UCHAR AndXCommand; Secondary (X) command; 0xFF = none UCHAR AndXReserved; Reserved (must be 0) USHORT AndXOffset; Offset to next command WordCount USHORT Fid; File handle USHORT FileAttributes; UTIME LastWriteTime; ULONG DataSize; Current file size USHORT GrantedAccess; Access permissions actually allowed USHORT FileType; Type of file opened USHORT DeviceState; State of the named pipe USHORT Action; Action taken ULONG ServerFid; Server unique file id USHORT Reserved; Reserved (must be 0) USHORT ByteCount; Count of data bytes = 0 DesiredAccess describes the access the client desires for the file; the encoding of this field is described in the "Access Mode Encoding" section elsewhere in this document. OpenFunction specifies the action to be taken depending on whether or not the file exists (see section 3.7). Action in the response specifies the action as a result of the Open request (see section 3.8). SearchAttributes indicates the attributes that the file must have to be found while searching to see if it exists. The encoding of this field is described in the "File Attribute Encoding" section elsewhere in this document. If SEARCHATTRIBUTES is zero then only normal files are Heizer, et al expires December 1996 [Page 171] INTERNET-DRAFT CIFS/1.0 June 1996 returned. If the system file, hidden or directory attributes are specified then the search is inclusive -- both the specified type(s) of files and normal files are returned. FILETYPE returns the kind of resource actually opened: Name Value Description ========================== ====== ================================== FileTypeDisk 0 Disk file or directory as defined in the attribute field FileTypeByteModePipe 1 Named pipe in byte mode FileTypeMessageModePipe 2 Named pipe in message mode FileTypePrinter 3 Spooled printer FileTypeUnknown 0xFFFF Unrecognized resource type If bit0 of FLAGS is clear, the FileAttributes, LastWriteTime, DataSize, FileType, and DeviceState have indeterminate values in the response. This SMB can request an oplock on the opened file. Oplocks are fully described in the "Oplocks" section elsewhere in this document, and there is also discussion of oplocks in the SMB_COM_LOCKING_ANDX SMB description. BIT1 and BIT2 of the FLAGS field are used to request oplocks during open. The following SMBs may follow SMB_COM_OPEN_ANDX: SMB_COM_READ SMB_COM_READ_ANDX SMB_COM_IOCTL 5.9 PROCESS_EXIT: Process Exit* This command informs the server that a client process has terminated. The server must close all files opened by PID in the SMB header. This must automatically release all locks the process holds. Client Request Description Heizer, et al expires December 1996 [Page 172] INTERNET-DRAFT CIFS/1.0 June 1996 ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 This SMB should not generate any errors from the server, unless the server is a USER MODE server and UID in the SMB header is invalid. Clients are not required to send this SMB, they can do all cleanup necessary by sending close SMBs to the server to release resources. In fact, clients who have negotiated LANMAN 1.0 and later probably do not send this message at all. Heizer, et al expires December 1996 [Page 173] INTERNET-DRAFT CIFS/1.0 June 1996 5.10 QUERY_INFORMATION: Get File Attributes This request is sent to obtain information about a file. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 STRING FileName[]; File name FileName is the fully qualified name of the file relative to the Tid in the header. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 10 USHORT FileAttributes; UTIME LastWriteTime; Time of last write ULONG FileSize; File size USHORT Reserved [5]; Reserved - client should ignore USHORT ByteCount; Count of data bytes = 0 FileAttributes are as described in the "Attributes Encoding" section of this document. Note that FileSize is limited to 32 bits, this request is inappropriate for files whose size is too large. Heizer, et al expires December 1996 [Page 174] INTERNET-DRAFT CIFS/1.0 June 1996 5.11 QUERY_INFORMATION2: Get File Information This SMB is gets information about the file represented by FID. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 2 USHORT Fid; File handle USHORT ByteCount; Count of data bytes = 0 Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 11 SMB_DATE CreationDate; SMB_TIME CreationTime; SMB_DATE LastAccessDate; SMB_TIME LastAccessTime; SMB_DATE LastWriteDate; SMB_TIME LastWriteTime; ULONG FileDataSize; File end of data ULONG FileAllocationSize; File allocation size USHORT FileAttributes; USHORT ByteCount; Count of data bytes; min = 0 The file being interrogated is specified by FID, which must possess at least read permission. Heizer, et al expires December 1996 [Page 175] INTERNET-DRAFT CIFS/1.0 June 1996 FileAttributes are described in the "File Attribute Encoding" section elsewhere in this document. 5.12 READ: Read File* The read message is sent to read bytes of a resource indicated by FID in the SMB header. Client Request Description =============================== ==================================== UCHAR WordCount; Count of parameter words = 5 USHORT Fid; File handle USHORT Count; Count of bytes being requested ULONG Offset; Offset in file of first byte to read USHORT Remaining; Estimate of bytes to read if nonzero USHORT ByteCount; Count of data bytes = 0 COUNT is used to specify the requested number of bytes. OFFSET specifies the offset in the file of the first byte to be read. Note that this offset is limited to 32 bits, so this client request is inappropriate for files having 64 bit offsets. REMAINING is advisory. If the value is not zero, then it is taken as an estimate of the total number of bytes that will be read, including those read by this request. This additional information may be used by the server to optimize buffer allocation or read-ahead. Heizer, et al expires December 1996 [Page 176] INTERNET-DRAFT CIFS/1.0 June 1996 Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 5 USHORT Count; Count of bytes actually returned USHORT Reserved [4]; Reserved (must be 0) USHORT ByteCount; Count of data bytes UCHAR BufferFormat; 0x01 -- Data block USHORT DataLength; Length of data BYTECOUNT is the number of bytes actually being returned. If FID refers to a disk file, BYTECOUNT may be less than the count requested only if a read specifies bytes beyond the current file size. In this case only the bytes that exist are returned. A read completely beyond the end of file results in a response of length zero. This is the only circumstance when a zero length response is generated. A count returned which is less than the count requested is the end of file indicator. If a Read requests more data than can be placed in a message of the maximum-xmit-size for the TID specified, the server will abort the connection to the client. 5.13 READ_MPX: Read Block Multiplex* The Read Block Multiplexed protocol is used to maximize the performance of reading a large block of data from the server to the client while still allowing other operations to take place between the client and server in the meantime. The NT server supports SMB_COM_READ_MPX only over connectionless transports. Client Request Description ================================ =================================== UCHAR WordCount; Count of parameter words = 8 USHORT Fid; File handle ULONG Offset; Offset in file to begin read Heizer, et al expires December 1996 [Page 177] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT MaxCount; Max bytes to return (maximum 65535) USHORT MinCount; Min bytes to return (normally 0) ULONG Reserved1; USHORT Reserved2; USHORT ByteCount; Count of data bytes = 0 FID identifies the resource being read, and may refer to a disk file or a spooled printer. TIMEOUT is the number of milliseconds to wait for completion FID refers to a named pipe. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 8 ULONG Offset; Offset in file where data read USHORT Count; Total bytes being returned USHORT Reserved; USHORT DataCompactionMode; USHORT Reserved; USHORT DataLength; Number of data bytes this buffer USHORT DataOffset; Offset (from header start) to data USHORT ByteCount; Count of data bytes UCHAR Pad[]; Pad to SHORT or LONG UCHAR Data[]; Data (size = DataLength) Other requests may be active between the client and server. The server responds with the one or more response messages as defined above until Heizer, et al expires December 1996 [Page 178] INTERNET-DRAFT CIFS/1.0 June 1996 the requested data amount has been returned. Each response contains the PID and MID of the original request and the OFFSET and COUNT of describing the placement of the data within the file. The client knows the maximum amount of data bytes which the server may return (from MAXCOUNT of the request). Thus the client initializes its bytes expected variable to this value. The server then informs the client of the actual amount being returned via each part of the response in COUNT. The server may reduce the expected bytes by lowering the total number of bytes expected in COUNT in any response. When the amount of data bytes received (sum of the DATALENGTH fields) equals the total amount of data bytes expected (smallest COUNT received), then the client has received all the data bytes. This allows the protocol to work even if the responses are received out of sequence. Note that DATALENGTH being returned here can not be larger than the smaller of the client's buffer size (as specified in MAXBUFFERSIZE on the COM_SESSION_SETUP_AND_X client request SMB) or the server's buffer size (as specified in MAXBUFFERSIZE of the COM_NEGOTIATE server response SMB). As is true in SMB_COM_READ, the total number of bytes returned may be less than the number requested only if a read specifies bytes beyond the current file size and FID refers to a disk file. In this case only the bytes that exist are returned. A read completely beyond the end of file will result in a single response with a zero value in COUNT. If the total number of bytes returned is less than the number of bytes requested, this indicates end of file (if reading other than a standard blocked disk file, only ZERO bytes returned indicates end of file). Once started, the Read Block Multiplexed operation is expected to go to completion. The client is expected to receive all the responses generated by the server. Conflicting commands (such as file close) must not be sent to the server while a multiplexed operation is in progress. The flow for the SMB_COM_READ_MPX protocol is: client ---------------> Read MPX. request >--------------------- > server client <--------------< Read MPX response 1 with data <--------- - server client <--------------< Read MPX response 2 with data <--------- - server ... client <--------------< Read MPX response n with data <--------- - server Heizer, et al expires December 1996 [Page 179] INTERNET-DRAFT CIFS/1.0 June 1996 5.14 SEARCH: Search Directory using Wildcards* This command is used to search directories. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 2 USHORT MaxCount; Number of dir. entries to return USHORT SearchAttributes; USHORT ByteCount; Count of data bytes; min = 5 UCHAR BufferFormat1; 0x04 -- ASCII UCHAR FileName[]; File name, may be null UCHAR BufferFormat2; 0x05 -- Variable block USHORT ResumeKeyLength; Length of resume key, may be 0 UCHAR ResumeKey[]; Resume key FILENAME specifies the file to be sought. SEARCHATTRIBUTES indicates the attributes that the file must have, and is described in the "File Attribute Encoding" section of this document. If SEARCHATTRIBUTES is zero then only normal files are returned. If the system file, hidden or directory attributes are specified then the search is inclusive-both the specified type(s) of files and normal files are returned. If the volume label attribute is specified then the search is exclusive, and only the volume label entry is returned. MAXCOUNT specifies the number of directory entries to be returned. Heizer, et al expires December 1996 [Page 180] INTERNET-DRAFT CIFS/1.0 June 1996 Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Count; Number of entries returned USHORT ByteCount; Count of data bytes; min = 3 UCHAR BufferFormat; 0x05 -- Variable block USHORT DataLength; Length of data UCHAR DirectoryInformationData[]; Data The response will contain one or more directory entries as determined by the COUNT field. No more than MAXCOUNT entries will be returned. Only entries that match the sought FILENAME and SEARCHATTRIBUTES combination will be returned. RESUMEKEY must be null (length = 0) on the initial search request. Subsequent search requests intended to continue a search must contain the RESUMEKEY field extracted from the last directory entry of the previous response. RESUMEKEY is self-contained, for on calls containing a non-zero RESUMEKEY neither the SEARCHATTRIBUTES or FILENAME fields will be valid in the request. RESUMEKEY has the following format: Resume Key Field Description ================================== ================================= UCHAR Reserved; bit 7 - consumer use bits 5,6 - system use (must preserve) bits 0-4 - server use (must preserve) UCHAR FileName[11]; Name of the returned file UCHAR ReservedForServer[5]; Client must not modify UCHAR ReservedForConsumer[4]; Server must not modify Heizer, et al expires December 1996 [Page 181] INTERNET-DRAFT CIFS/1.0 June 1996 FILENAME is 8.3 format, with the three character extension left justified into FILENAME[9-11]. If the client is prior to the LANMAN1.0 dialect, the returned FILENAME should be uppercased. SMB_COM_SEARCH terminates when either the requested maximum number of entries that match the named file are found, or the end of directory is reached without the maximum number of matches being found. A response containing no entries indicates that no matching entries were found between the starting point of the search and the end of directory. There may be multiple matching entries in response to a single request as SMB_COM_SEARCH supports wildcards in the last component of FILENAME of the initial request. Returned directory entries in the DIRECTORYINFORMATIONDATA field of the response each have the following format: Directory Information Field Description ================================== ================================= SMB_RESUME_KEY ResumeKey; Described above UCHAR FileAttributes; Attributes of the found file SMB_TIME LastWriteTime; Time file was last written SMB_DATE LastWriteDate; Date file was last written ULONG FileSize; Size of the file UCHAR FileName[13]; ASCII, space-filled null terminated FILENAME must conform to 8.3 rules, and is padded after the extension with 0x20 characters if necessary. If the client has negotiated a dialect prior to the LANMAN1.0 dialect, or if BIT0 of the FLAGS2 SMB header field of the request is clear, the returned FILENAME should be uppercased. As can be seen from the above structure, SMB_COM_SEARCH can not return long filenames, and can not return UNICODE filenames. Files which have a size greater than 2^32 bytes should have the least significant 32 bits of their size returned in FILESIZE. Heizer, et al expires December 1996 [Page 182] INTERNET-DRAFT CIFS/1.0 June 1996 5.15 SET_INFORMATION: Set File Attributes This message is sent to change the information about a file. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 8 USHORT FileAttributes; Attributes of the file UTIME LastWriteTime; Time of last write USHORT Reserved [5]; Reserved (must be 0) USHORT ByteCount; Count of data bytes; min = 2 UCHAR BufferFormat; 0x04 STRING FileName[]; File name FileName is the fully qualified name of the file relative to the TID. Support of all parameters is optional. A server which does not implement one of the parameters will ignore that field. If the LastWriteTime field contain zero then the file's time is not changed. Heizer, et al expires December 1996 [Page 183] INTERNET-DRAFT CIFS/1.0 June 1996 Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 5.16 SET_INFORMATION2: Set File Information Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 7 USHORT Fid; File handle SMB_DATE CreationDate; SMB_TIME CreationTime; SMB_DATE LastAccessDate; SMB_TIME LastAccessTime; SMB_DATE LastWriteDate; SMB_TIME LastWriteTime; USHORT ByteCount; Count of data bytes = 0 SMB_COM_SET_INFORMATION2 sets information about the file represented by Fid. The target file is updated from the values specified. A date or time value or zero indicates to leave that specific date and time unchanged. Heizer, et al expires December 1996 [Page 184] INTERNET-DRAFT CIFS/1.0 June 1996 Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 FID must be open with (at least) write permission. 5.17 QUERY_INFORMATION_DISK: Get Disk Attributes The SMB_COM_QUERY_INFORMATION_DISK command is used to determine the capacity and remaining free space on the drive hosting the directory structure indicated by Tid in the SMB header. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 5 USHORT TotalUnits; Total allocation units per server USHORT BlocksPerUnit; Blocks per allocation unit USHORT BlockSize; Block size (in bytes) USHORT FreeUnits; Number of free units USHORT Reserved; Reserved (client should ignore) Heizer, et al expires December 1996 [Page 185] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT ByteCount; Count of data bytes = 0 The blocking/allocation units used in this response may be independent of the actual physical or logical blocking/allocation algorithm(s) used internally by the server. However, they must accurately reflect the amount of space on the server. This SMB only returns 16 bits of information for each field, which may not be large enough for some disk systems. In particular TotalUnits is commonly > 64K. Fortunately, it turns out the all the client cares about is the total disk size, in bytes, and the free space, in bytes. So, it is reasonable for a server to adjust the relative values of BlocksPerUnit and BlockSize to accommodate. If after all adjustment, the numbers are still too high, the largest possible values for TotalUnit or FreeUnits (i.e. 0xFFFF) should be returned. 5.18 TRANS2_OPEN2: Create or Open File with Extended Attributes This transaction is used to open or create a file having extended attributes. Heizer, et al expires December 1996 [Page 186] INTERNET-DRAFT CIFS/1.0 June 1996 Client Request Value ============================ ======================================= WordCount 15 TotalDataCount Total size of extended attribute list DataOffset Offset to extended attribute list in this request SetupCount 1 Setup[0] TRANS2_OPEN2 Parameter Block Encoding Description ============================ ======================================= USHORT Flags; Additional information: bit set- 0 - return additional info 1 - exclusive oplock requested 2 - batch oplock requested 3 - return total length of EAs USHORT DesiredAccess; Requested file access USHORT Reserved1; Ought to be zero. Ignored by the server. USHORT FileAttributes; Attributes for file if create SMB_TIME CreationTime; Creation time to apply to file if create SMB_DATE CreationDate; Creation date to apply to file if create USHORT OpenFunction; Open function Heizer, et al expires December 1996 [Page 187] INTERNET-DRAFT CIFS/1.0 June 1996 ULONG AllocationSize; Bytes to reserve on create or truncate USHORT Reserved [5]; Must be zero STRING FileName; Name of file to open or create UCHAR Data[ TotalDataCount ] FEAList structure for file to be created If secondary requests are required, they must contain 0 parameter bytes, and the FID in the secondary request is 0xFFFF. DESIREDACCESS is encoded as described in the "Access Mode Encoding" section elsewhere in this document. FILEATTRIBUTES are encoded as described in the "File Attribute Encoding" section elsewhere in this document. OPENFUNCTION specifies the action to be taken depending on whether or not the file exists (see section 3.7) . ACTION in the response specifies the action as a result of this request (see section 3.8). Heizer, et al expires December 1996 [Page 188] INTERNET-DRAFT CIFS/1.0 June 1996 Response Parameter Block Description ========================== ========================================= USHORT Fid; File handle USHORT FileAttributes; Attributes of file SMB_TIME CreationTime; Last modification time SMB_DATE CreationDate; Last modification date ULONG DataSize; Current file size USHORT GrantedAccess; Access permissions actually allowed USHORT FileType; Type of file USHORT DeviceState; State of IPC device (e.g. pipe) USHORT Action; Action taken ULONG Reserved; USHORT EaErrorOffset; Offset into EA list if EA error ULONG EaLength; Total EA length for opened file FILETYPE returns the kind of resource actually opened: Name Value Description ======================= ====== ===================================== FileTypeDisk 0 Disk file or directory as defined in the attribute field FileTypeByteModePipe 1 Named pipe in byte mode FileTypeMessageModePipe 2 Named pipe in message mode FileTypePrinter 3 Spooled printer FileTypeUnknown 0xFFFF Unrecognized resource type Heizer, et al expires December 1996 [Page 189] INTERNET-DRAFT CIFS/1.0 June 1996 DeviceState is applicable only if the FileType is FileTypeByteModePipe or FileTypeMessageModePipe and is encoded as in section 3.9. If an error was detected in the incoming EA list, the offset of the error is returned in EaErrorOffset. If BIT0 of FLAGS in the request is clear, the FileAttributes, CREATIONTIME, CREATIONDATE, DATASIZE, GRANTEDACCESS, FILETYPE, and DEVICESTATE have indeterminate values in the response. Similarly, if BIT3 of the request is clear, EALENGTH in the response has an indeterminate value in the response. This SMB can request an oplock on the opened file. Oplocks are fully described in the "Oplocks" section elsewhere in this document, and there is also discussion of oplocks in the SMB_COM_LOCKING_ANDX SMB description. BIT1 and BIT2 of the FLAGS field are used to request oplocks during open. 5.19 TREE_CONNECT: Tree Connect When a client connects to a server resource, an SMB_COM_TREE_CONNECT message is generated to the server. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes; min = 4 UCHAR BufferFormat1; 0x04 STRING Path[]; Server name and share name UCHAR BufferFormat2; 0x04 STRING Password[]; Password UCHAR BufferFormat3; 0x04 STRING Service[]; Service name The serving machine verifies the combination and returns an error code or an identifier. The full name is included in this request message and the identifier identifying the connection is returned in the TID field of the SMB header. The TID field in the client request is ignored. The Heizer, et al expires December 1996 [Page 190] INTERNET-DRAFT CIFS/1.0 June 1996 meaning of this identifier (TID) is server specific; the client must not associate any specific meaning to it. If the negotiated dialect is prior to LANMAN1.0 and the client has not sent a successful SMB_COM_SESSION_SETUP_ANDX request when the tree connect arrives, a user level server must nevertheless validate the client's credentials as discussed earlier in this document. If the negotiated dialect is LANMAN1.0 and later, then it is a protocol violation for the client to send this message prior to a successful SMB_COM_SESSION_SETUP_ANDX. Having received an SMB_COM_SESSION_SETUP_AND_X, the server ignores PASSWORD. PATH follows UNC style syntax, that is to say it is encoded as \\server\share and it indicates the name of the resource the client wishes to connect to. If the server is paused, administrative privilege is required to connect to any share; if the server is not paused, administrative privilege is required only for administrative shares (C$, etc.). Of course, the server can enforce whatever policy it desires to govern share access. Such policies may include valid times of day, software usage license limits, number of simultaneous server users or share users, etc. The Service component indicates the type of resource the client intends to access. Valid values are: Service Description Earliest Dialect Allowed ======== ======================== ================================ A: disk share PC NETWORK PROGRAM 1.0 LPT1: printer PC NETWORK PROGRAM 1.0 IPC named pipe MICROSOFT NETWORKS 3.0 COMM communications device MICROSOFT NETWORKS 3.0 ????? any type of device MICROSOFT NETWORKS 3.0 The SMB server responds with: Server Response Description ================================ ================================= Heizer, et al expires December 1996 [Page 191] INTERNET-DRAFT CIFS/1.0 June 1996 UCHAR WordCount; Count of parameter words = 2 USHORT MaxBufferSize; Max size message the server handles USHORT Tid; Tree ID USHORT ByteCount; Count of data bytes = 0 If the negotiated dialect is MICROSOFT NETWORKS 1.03 or earlier, MaxBufferSize in the response message indicates the maximum size message that the server can handle. The client should not generate messages, nor expect to receive responses, larger than this. This must be constant for a given server. For newer dialects, this field is ignored. TID should be included in any future SMBs referencing this tree connection. Heizer, et al expires December 1996 [Page 192] INTERNET-DRAFT CIFS/1.0 June 1996 5.20 UNLOCK_BYTE_RANGE: Unlock Bytes* This message is sent to unlock the given byte range. OFFSET, COUNT, and PID must be identical to that specified in a prior successful lock. If an unlock references an address range that is not locked, no error is generated. Since OFFSET is a 32 bit quantity, this request is inappropriate for general locking within a very large file. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 5 USHORT Fid; File handle ULONG Count; Count of bytes to unlock ULONG Offset; Offset from start of file USHORT ByteCount; Count of data bytes = 0 Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 5.21 WRITE: Write Bytes* The write message is sent to write bytes into the resource indicated by FID in the SMB header. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 5 Heizer, et al expires December 1996 [Page 193] INTERNET-DRAFT CIFS/1.0 June 1996 USHORT Fid; File handle USHORT Count; Number of bytes to be written ULONG Offset; Offset in file to begin write USHORT Remaining; Bytes remaining to satisfy request USHORT ByteCount; Count of data bytes UCHAR BufferFormat; 0x01 -- Data block USHORT DataLength; Length of data UCHAR Data[ Count ]; The data to write COUNT specifies the number of bytes to be written. OFFSET is the offset in the file of the first byte to be written. Since offset is 32 bits, this request is inappropriate for general use in a very large file. REMAINING is advisory: if the value is not zero, then it is taken as an estimate of the number of bytes that will be written -including those written by this request. This additional information may be used by the server to optimize cache behavior. When FID represents a disk file and the request specifies a byte range beyond the current end of file, the file will be extended. Any bytes between the previous end of file and the requested offset are initialized to 0. When a write specifies a length of zero, the file is truncated (or extended) to the length specified by the offset. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Count; Count of bytes actually written USHORT ByteCount; Count of data bytes = 0 COUNT in the response indicates the actual number of bytes written, and for successful writes will always equal the count in the request message. If the number of bytes written differs from the number Heizer, et al expires December 1996 [Page 194] INTERNET-DRAFT CIFS/1.0 June 1996 requested and no error is indicated, then the server has no resources available with which to satisfy the complete write. If a Write sends a message of length greater than the MAXBUFFERSIZE for the TID specified, the server may abort the connection to the client. 5.22 WRITE_AND_UNLOCK: Write Bytes and Unlock Range* This request is used to first write the specified bytes and then unlock them. The locked portion of a file is "safe" to write behind because no other process can access the locked bytes until this process unlocks the bytes. Thus the client can buffer the locked bytes locally while they are being updated, then when the unlock request is received submit this protocol to both write and then unlock bytes. Whether or not this SMB is supported (along with SMB_COM_READ_AND_LOCK) is returned in BIT0 of the FLAGS field of the negotiate response. Client Request Description ================================ =================================== UCHAR WordCount; Count of parameter words = 5 USHORT Fid; File handle USHORT Count; Number of bytes to be written ULONG Offset; Offset in file to begin write USHORT Remaining; Bytes remaining to satisfy request USHORT ByteCount; Count of data bytes UCHAR BufferFormat; 0x01 -- Data block USHORT DataLength; Length of data COUNT specifies the number of bytes to be written. OFFSET is the offset in the file of the first byte to be written. Since offset is 16 bits, this request is inappropriate for general use in a very large file. REMAINING is advisory: if the value is not zero, then it is taken as an estimate of the number of bytes that will be written -including those written by this request. This additional information may be used by the server to optimize cache behavior. A value of 0 for COUNT is an error. Heizer, et al expires December 1996 [Page 195] INTERNET-DRAFT CIFS/1.0 June 1996 If the request specifies a byte range beyond the current end of file, the file will be extended. Any bytes between the previous end of file and the requested offset are initialized to 0. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Count; Count of bytes actually written USHORT ByteCount; Count of data bytes = 0 COUNT in the response indicates the actual number of bytes written, and for successful writes will always equal the count in the request message. If the number of bytes written differs from the number requested and no error is indicated, then the server has no resources available with which to satisfy the complete write. If a Write sends a message of length greater than the MAXBUFFERSIZE for the TID specified, the server may abort the connection to the client. If an error occurs on the write, the bytes remain locked. 5.23 WRITE_AND_CLOSE: Write Bytes and Close File* This request is used to first write the specified bytes and then close the file. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 6 USHORT Fid; File handle USHORT Count; Number of bytes to write ULONG Offset; Offset in file of first byte to write UTIME LastWriteTime; Time of last write USHORT ByteCount; 1 (for pad) + value of Count Heizer, et al expires December 1996 [Page 196] INTERNET-DRAFT CIFS/1.0 June 1996 UCHAR Pad; To force to doubleword boundary UCHAR Buffer[ Count ]; Data to write Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 12 USHORT Fid; File handle USHORT Count; Number of bytes to write ULONG Offset; Offset in file of first byte to write UTIME LastWriteTime; Time of last write ULONG Reserved[3]; Reserved, must be 0 USHORT ByteCount; 1 (for pad) + value of Count UCHAR Pad; To force to doubleword boundary UCHAR Buffer[Count]; Data to write Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Count; Count of bytes actually written USHORT ByteCount; Count of data bytes = 0 Since clients can formulate the request in either of two ways, WORDCOUNT must be used in order to correctly locate the data to be written. Heizer, et al expires December 1996 [Page 197] INTERNET-DRAFT CIFS/1.0 June 1996 COUNT specifies the number of bytes to be written. OFFSET is the offset in the file of the first byte to be written. Since OFFSET is 32 bits, this request is inappropriate for general use in a very large file. If LASTWRITETIME and LASTWRITEDATE are 0, the server should allow its local operating system to set the file's times. Otherwise, the server should set the time to the values requested. Failure to set the times, even if requested by the client in this message, should not result in an error response from the server. If COUNT is 0, the file is truncated (or extended) to OFFSET. If an error occurs on the write, the file should still be closed. 5.24 WRITE_MPX: Write Block Multiplex* Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 12 USHORT Fid; File handle USHORT Count; Total bytes, including this buffer USHORT Reserved; ULONG Offset; Offset in file to begin write ULONG Timeout; milliseconds to wait for completion USHORT WriteMode; Write mode: bit 0 - complete write to disk and send final result response bit 1 - return Remaining bit 7 - Connectionless mode ULONG RequestMask; Connectionless mode mask USHORT DataLength; Number of data bytes this buffer USHORT DataOffset; Offset (from header start) to Heizer, et al expires December 1996 [Page 198] INTERNET-DRAFT CIFS/1.0 June 1996 data USHORT ByteCount; Count of data bytes UCHAR Pad[]; Pad to SHORT or LONG UCHAR Data[]; Data (# = DataLength) Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 ULONG ResponseMask; OR of all masks received USHORT ByteCount; Count of data bytes = 0 SMB_COM_WRITE_MPX is used to maximize the performance of writing a large block of data from the client to the server. The NT server supports SMB_COM_WRITE_MPX only over connectionless transports, consequently BIT7 of WRITEMODE in the request must be set. FID in the request must refer to either a file or a spooled printer. MASK contains a bit mask indicating where in the transfer that the SMB belongs. The response which contains the logical OR of all of the MASK values received and is always generated. All in this exchange use the same SMB header MID value but only final message is a connectionless sequenced request (SEQUENCENUMBER is non-zero). The server keeps a RESPONSEMASK which is the logical or-ing of the REQUESTMASK value contained in each SMB_COM_WRITE_MPX received since the last sequenced SMB_COM_WRITE_MPX. The server only responds to the final (sequenced) command, and this response contains the accumulated RESPONSEMASK. The client uses the RESPONSEMASK received to determine which packets, if any, must be retransmitted. The server imposes no restrictions on the values in the mask nor upon the order or contiguity of the data being sent. The client uses this behavior to only send the missing parts in the next write sequence when retransmitting. The next SMB_COM_WRITE_MPX sequence sent must use a new SEQUENCENUMBER value or the server will incorrectly respond with the mask from the previous SMB_COM_WRITE_MPX command. The flow is: Heizer, et al expires December 1996 [Page 199] INTERNET-DRAFT CIFS/1.0 June 1996 Client Sequence <-> Server Number ================= ========= ==== ===================== SMB_COM_WRITE_MPX 0 -> SMB_COM_WRITE_MPX 0 -> ... SMB_COM_WRITE_MPX S -> S <- SMB_COM_WRITE_MPX OK SMB_COM_WRITE_MPX 0 -> SMB_COM_WRITE_MPX 0 -> .... SMB_COM_WRITE_MPX S+1 -> S+1 <- SMB_COM_WRITE_MPX OK Other SMB requests can intervene during this protocol exchange. A server response will be generated only after the sequenced SMB_COM_WRITE_MPX has been received unless this SMB is received over a connection oriented transport (in which case the error response is immediately sent). At the time of the request, the client knows the number of data bytes expected to be sent and passes this information to the server in COUNT. The server can use this information to reserve buffer space, if possible. If BIT0 of WRITEMODE is clear, the request assumed to be a form of write behind on the part of the client. If an error occurs while writing data to disk such as disk full, the next access of the file handle (another write, close, read, etc.) will return the fact that the error occurred. If BIT0 of WRITEMODE is set, the server will collect all the data, write it to disk and then send a final response indicating the result of the write . The total number of bytes written is also returned in this response. Heizer, et al expires December 1996 [Page 200] INTERNET-DRAFT CIFS/1.0 June 1996 5.25 WRITE_PRINT_FILE: Write to Print File* This message is sent to write bytes into a print spool file. Client Request Description ================================== ================================= UCHAR WordCount; Count of parameter words = 1 USHORT Fid; File handle USHORT ByteCount; Count of data bytes; min = 4 UCHAR BufferFormat; 0x01 -- Data block USHORT DataLength; Length of data UCHAR Data[]; Data FID indicates the print spool file to be written, it must refer to a print spool file. BYTECOUNT specifies the number of bytes to be written, and must be less than MAXBUFFERSIZE for the Tid specified. DATA contains the bytes to append to the print spool file. The first SETUPLENGTH bytes in the resulting print spool file contain printer setup data. SETUPLENGTH is specified in the SMB_COM_OPEN_PRINT_FILE SMB request. Server Response Description ================================== ================================= UCHAR WordCount; Count of parameter words = 0 USHORT ByteCount; Count of data bytes = 0 Servers which negotiate a protocol dialect of LANMAN1.0 or later also support the application of normal write requests to print spool files. Heizer, et al expires December 1996 [Page 201] INTERNET-DRAFT CIFS/1.0 June 1996 6. SMB Symbolic Constants 6.1 SMB Command Codes The following values have been assigned for the SMB Commands. SMB_COM_CREATE_DIRECTORY 0x00 SMB_COM_DELETE_DIRECTORY 0x01 SMB_COM_OPEN 0x02 SMB_COM_CREATE 0x03 SMB_COM_CLOSE 0x04 SMB_COM_FLUSH 0x05 SMB_COM_DELETE 0x06 SMB_COM_RENAME 0x07 SMB_COM_QUERY_INFORMATION 0x08 SMB_COM_SET_INFORMATION 0x09 SMB_COM_READ 0x0A SMB_COM_WRITE 0x0B SMB_COM_LOCK_BYTE_RANGE 0x0C SMB_COM_UNLOCK_BYTE_RANGE 0x0D SMB_COM_CREATE_TEMPORARY 0x0E SMB_COM_CREATE_NEW 0x0F SMB_COM_CHECK_DIRECTORY 0x10 SMB_COM_PROCESS_EXIT 0x11 SMB_COM_SEEK 0x12 SMB_COM_LOCK_AND_READ 0x13 SMB_COM_WRITE_AND_UNLOCK 0x14 SMB_COM_READ_RAW 0x1A Heizer, et al expires December 1996 [Page 202] INTERNET-DRAFT CIFS/1.0 June 1996 SMB_COM_READ_MPX 0x1B SMB_COM_READ_MPX_SECONDARY 0x1C SMB_COM_WRITE_RAW 0x1D SMB_COM_WRITE_MPX 0x1E SMB_COM_WRITE_COMPLETE 0x20 SMB_COM_SET_INFORMATION2 0x22 SMB_COM_QUERY_INFORMATION2 0x23 SMB_COM_LOCKING_ANDX 0x24 SMB_COM_TRANSACTION 0x25 SMB_COM_TRANSACTION_SECONDARY 0x26 SMB_COM_IOCTL 0x27 SMB_COM_IOCTL_SECONDARY 0x28 SMB_COM_COPY 0x29 SMB_COM_MOVE 0x2A SMB_COM_ECHO 0x2B SMB_COM_WRITE_AND_CLOSE 0x2C SMB_COM_OPEN_ANDX 0x2D SMB_COM_READ_ANDX 0x2E SMB_COM_WRITE_ANDX 0x2F SMB_COM_CLOSE_AND_TREE_DISC 0x31 SMB_COM_TRANSACTION2 0x32 SMB_COM_TRANSACTION2_SECONDARY 0x33 SMB_COM_FIND_CLOSE2 0x34 SMB_COM_FIND_NOTIFY_CLOSE 0x35 SMB_COM_TREE_CONNECT 0x70 SMB_COM_TREE_DISCONNECT 0x71 Heizer, et al expires December 1996 [Page 203] INTERNET-DRAFT CIFS/1.0 June 1996 SMB_COM_NEGOTIATE 0x72 SMB_COM_SESSION_SETUP_ANDX 0x73 SMB_COM_LOGOFF_ANDX 0x74 SMB_COM_TREE_CONNECT_ANDX 0x75 SMB_COM_QUERY_INFORMATION_DISK 0x80 SMB_COM_SEARCH 0x81 SMB_COM_FIND 0x82 SMB_COM_FIND_UNIQUE 0x83 SMB_COM_NT_TRANSACT 0xA0 SMB_COM_NT_TRANSACT_SECONDARY 0xA1 SMB_COM_NT_CREATE_ANDX 0xA2 SMB_COM_NT_CANCEL 0xA4 SMB_COM_OPEN_PRINT_FILE 0xC0 SMB_COM_WRITE_PRINT_FILE 0xC1 SMB_COM_CLOSE_PRINT_FILE 0xC2 SMB_COM_GET_PRINT_QUEUE 0xC3 Heizer, et al expires December 1996 [Page 204] INTERNET-DRAFT CIFS/1.0 June 1996 6.2 Named Pipe Transaction Protocol Subcommand Codes The subcommand codes, placed in SETUP[0], for named pipe operations are: SubCommand Code Value Description =================== ===== ========================================= CallNamedPipe 0x54 open/write/read/close pipe WaitNamedPipe 0x53 wait for pipe to be nonbusy PeekNmPipe 0x23 read but don't remove data QNmPHandState 0x21 query pipe handle modes SetNmPHandState 0x01 set pipe handle modes QNmPipeInfo 0x22 query pipe attributes TransactNmPipe 0x26 write/read operation on pipe RawReadNmPipe 0x11 read pipe in "raw" (non message mode) RawWriteNmPipe 0x31 write pipe "raw" (non message mode) */ 6.3 SMB_COM_TRANSACTION2 Subcommand codes The subcommand code for SMB_COM_TRANSACTION2 request is placed in Setup[0]. The parameters associated with any particular request are placed in the PARAMETERS vector of the request. The defined subcommand codes are: Heizer, et al expires December 1996 [Page 205] INTERNET-DRAFT CIFS/1.0 June 1996 Setup[0] Transaction2 Value Description Subcommand Code =============================== ===== ============================= TRANS2_OPEN2 0x00 Create file with extended attributes TRANS2_FIND_FIRST2 0x01 Begin search for files TRANS2_FIND_NEXT2 0x02 Resume search for files TRANS2_QUERY_FS_INFORMATION 0x03 Get file system information 0x04 Reserved TRANS2_QUERY_PATH_INFORMATION 0x05 Get information about a named file or directory TRANS2_SET_PATH_INFORMATION 0x06 Set information about a named file or directory TRANS2_QUERY_FILE_INFORMATION 0x07 Get information about a handle TRANS2_SET_FILE_INFORMATION 0x08 Set information by handle TRANS2_FSCTL 0x09 Not implemented by NT server TRANS2_IOCTL2 0x0A Not implemented by NT server TRANS2_FIND_NOTIFY_FIRST 0x0B Not implemented by NT server TRANS2_FIND_NOTIFY_NEXT 0x0C Not implemented by NT server TRANS2_CREATE_DIRECTORY 0x0D Create directory with extended attributes TRANS2_SESSION_SETUP 0x0E Session setup with extended security information TRANS2_GET_DFS_REFERRAL 0x10 Get a DFS referral TRANS2_REPORT_DFS_INCONSISTENCY 0x11 Report a DFS knowledge inconsistency 6.4 SMB_COM_NT_TRANSACTION Subcommand Codes Heizer, et al expires December 1996 [Page 206] INTERNET-DRAFT CIFS/1.0 June 1996 For these transactions, FUNCTION in the primary client request indicates the operation to be performed. It may assume one of the following values: SubCommand Code Value Description ================================== ===== =========================== NT_TRANSACT_CREATE 1 File open/create NT_TRANSACT_IOCTL 2 Device IOCTL NT_TRANSACT_SET_SECURITY_DESC 3 Set security descriptor NT_TRANSACT_NOTIFY_CHANGE 4 Start directory watch NT_TRANSACT_RENAME 5 Reserved (Handle-based rename) NT_TRANSACT_QUERY_SECURITY_DESC 6 Retrieve security descriptor info Heizer, et al expires December 1996 [Page 207] INTERNET-DRAFT CIFS/1.0 June 1996 6.5 SMB Protocol Dialect Constants This is the list of SMB protocol dialects, ordered from least functional (earliest) version to most functional (most recent) version: Dialect Name Comment =========================== ======================================== PC NETWORK PROGRAM 1.0 The original MSNET SMB protocol (otherwise known as the "core protocol") PCLAN1.0 Some versions of the original MSNET defined this as an alternate to the core protocol name MICROSOFT NETWORKS 1.03 This is used for the MS-NET 1.03 product. It defines Lock&Read,Write&Unlock, and a special version of raw read and raw write. MICROSOFT NETWORKS 3.0 This is the DOS LANMAN 1.0 specific protocol. It is equivalent to the LANMAN 1.0 protocol, except the server is required to map errors from the OS/2 error to an appropriate DOS error. LANMAN1.0 This is the first version of the full LANMAN 1.0 protocol LM1.2X002 This is the first version of the full LANMAN 2.0 protocol DOS LM1.2X002 This is the dos equivalent of the LM1.2X002 protocol. It is identical to the LM1.2X002 protocol, but the server will perform error mapping to appropriate DOS errors. Heizer, et al expires December 1996 [Page 208] INTERNET-DRAFT CIFS/1.0 June 1996 DOS LANMAN2.1 DOS LANMAN2.1 LANMAN2.1 OS/2 LANMAN2.1 Windows for Workgroups 3.1a Windows for Workgroups Version 1.0 NT LM 0.12 The SMB protocol designed for NT networking. This has special SMBs which duplicate the NT semantics. SMB servers select the most recent version of the protocol known to both client and server. Any SMB server which supports dialects newer than the original core dialect must support all the messages and semantics of the dialects between the core dialect and the newer one. This is to say that a server which supports the NT LM 0.12 dialect must also support all of the messages of the previous 10 dialects. It is the client's responsibility to ensure it only sends SMBs which are appropriate to the dialect negotiated. Clients must be prepared to receive an SMB response from an earlier protocol dialect -- even if the client used the most recent form of the request. Heizer, et al expires December 1996 [Page 209] INTERNET-DRAFT CIFS/1.0 June 1996 7. Error Codes and Classes This section lists all of the valid values for STATUS.DOSERROR.ERRORCLASS, and most of the error codes for STATUS.DOSERROR.ERROR. The following error classes may be returned by the server to the client. Class Code Comment ======= ==== ==================================================== SUCCESS 0 The request was successful. ERRDOS 0x01 Error is from the core DOS operating system set. ERRSRV 0x02 Error is generated by the server network file manager. ERRHRD 0x03 Error is an hardware error. ERRCMD 0xFF Command was not in the "SMB" format. The following error codes may be generated with the SUCCESS error class. Class Code Comment ======= ==== ==================================================== SUCCESS 0 The request was successful. The following error codes may be generated with the ERRDOS error class. When an SMB dialect greater than equal to LANMAN 1.0 has been nego- tiated, all of the error codes below may be generated plus any of the error codes defined for OS/2 (see OS/2 operating system documentation for complete list of OS/2 error codes). When an earlier dialect has been negotiated, the server must map additional OS/2 (or OS/2 like) errors to the errors listed below. Heizer, et al expires December 1996 [Page 210] INTERNET-DRAFT CIFS/1.0 June 1996 Error Code Description =============== ===== ============================================= ERRbadfunc 1 Invalid function. The server did not recognize or could not perform a system call generated by the server, e.g., set the DIRECTORY attribute on a data file, invalid seek mode. ERRbadfile 2 File not found. The last component of a file's pathname could not be found. ERRbadpath 3 Directory invalid. A directory component in a pathname could not be found. ERRnofids 4 Too many open files. The server has no file handles available. ERRnoaccess 5 Access denied, the client's context does not permit the requested function. This includes the following conditions: o invalid rename command o write to fid open for read only o read on fid open for write only o attempt to delete a non-empty directory ERRbadfid 6 Invalid file handle. The file handle specified was not recognized by the server. ERRbadmcb 7 Memory control blocks destroyed. ERRnomem 8 Insufficient server memory to perform the requested function. ERRbadmem 9 Invalid memory block address. ERRbadenv 10 Invalid environment. ERRbadformat 11 Invalid format. ERRbadaccess 12 Invalid open mode. ERRbaddata 13 Invalid data (generated only by IOCTL calls within the server). Heizer, et al expires December 1996 [Page 211] INTERNET-DRAFT CIFS/1.0 June 1996 ERRbaddrive 15 Invalid drive specified. ERRremcd 16 A Delete Directory request attempted to remove the server's current directory. ERRdiffdevice 17 Not same device (e.g., a cross volume rename was attempted) ERRnofiles 18 A File Search command can find no more files matching the specified criteria. ERRbadshare 32 The sharing mode specified for an Open conflicts with existing FIDs on the file. ERRlock 33 A Lock request conflicted with an existing lock or specified an invalid mode, or an Unlock requested attempted to remove a lock held by another process. ERRfilexists 80 The file named in a Create Directory, Make New File or Link request already exists. The error may also be generated in the Create and Rename transaction. ERRbadpipe 230 Pipe invalid. ERRpipebusy 231 All instances of the requested pipe are busy. ERRpipeclosing 232 Pipe close in progress. ERRnotconnected 233 No process on other end of pipe. ERRmoredata 234 There is more data to be returned. Heizer, et al expires December 1996 [Page 212] INTERNET-DRAFT CIFS/1.0 June 1996 The following error codes may be generated with the ERRSRV error class. Error Code Description =============== ===== ============================================= ERRerror 1 Non-specific error code. It is returned under the following conditions: o resource other than disk space exhausted (e.g. TIDs) o first SMB command was not negotiate o multiple negotiates attempted o internal server error ERRbadpw 2 Bad password - name/password pair in a Tree Connect or Session Setup are invalid. ERRaccess 4 The client does not have the necessary access rights within the specified context for the requested function. ERRinvnid 5 The Tid specified in a command was invalid. ERRinvnetname 6 Invalid network name in tree connect. ERRinvdevice 7 Invalid device - printer request made to non- printer connection or non-printer request made to printer connection. ERRqfull 49 Print queue full (files) -- returned by open print file. ERRqtoobig 50 Print queue full -- no space. ERRqeof 51 EOF on print queue dump. ERRinvpfid 52 Invalid print file FID. ERRsmbcmd 64 The server did not recognize the command received. ERRsrverror 65 The server encountered an internal error, e.g., system file unavailable. ERRfilespecs 67 The Fid and pathname parameters contained an invalid combination of values. Heizer, et al expires December 1996 [Page 213] INTERNET-DRAFT CIFS/1.0 June 1996 ERRbadpermits 69 The access permissions specified for a file or directory are not a valid combination. The server cannot set the requested attribute. ERRsetattrmode 71 The attribute mode in the Set File Attribute request is invalid. ERRpaused 81 Server is paused. (reserved for messaging) ERRmsgoff 82 Not receiving messages. (reserved for messaging). ERRnoroom 83 No room to buffer message. (reserved for messaging). ERRrmuns 87 Too many remote user names. (reserved for messaging). ERRtimeout 88 Operation timed out. ERRnoresource 89 No resources currently available for request. ERRtoomanyuids 90 Too many Uids active on this session. ERRbaduid 91 The Uid is not known as a valid user identifier on this session. ERRusempx 250 Temporarily unable to support Raw, use MPX mode. ERRusestd 251 Temporarily unable to support Raw, use standard read/write. ERRcontmpx 252 Continue in MPX mode. ERRnosupport 65535 Function not supported. Heizer, et al expires December 1996 [Page 214] INTERNET-DRAFT CIFS/1.0 June 1996 The following error codes may be generated with the ERRHRD error class. Error Code Description =============== ===== ============================================= ERRnowrite 19 Attempt to write on write-protected media ERRbadunit 20 Unknown unit. ERRnotready 21 Drive not ready. ERRbadcmd 22 Unknown command. ERRdata 23 Data error (CRC). ERRbadreq 24 Bad request structure length. ERRseek 25 Seek error. ERRbadmedia 26 Unknown media type. ERRbadsector 27 Sector not found. ERRnopaper 28 Printer out of paper. ERRwrite 29 Write fault. ERRread 30 Read fault. ERRgeneral 31 General failure. ERRbadshare 32 A open conflicts with an existing open. ERRlock 33 A Lock request conflicted with an existing lock or specified an invalid mode, or an Unlock requested attempted to remove a lock held by another process. ERRwrongdisk 34 The wrong disk was found in a drive. ERRFCBUnavail 35 No FCBs are available to process request. ERRsharebufexc 36 A sharing buffer has been exceeded. Heizer, et al expires December 1996 [Page 215] INTERNET-DRAFT CIFS/1.0 June 1996 8. Legal Notice Microsoft does not know of any third-party rights that are violated by this contribution. Microsoft makes no other representations regarding this contribution. 9. References [1] P. Mockapetris, "Domain Names - Concepts And Facilities", RFC 1034, November 1987 [2] P. Mockapetris, "Domain Names - Implementation And Specification", RFC 1035, November 1987 [3] Karl Auerbach, "Protocol Standard For A Netbios Service On A Tcp/Udp Transport: Concepts And Methods", RFC 1001, March 1987 [4] Karl Auerbach, "Protocol Standard For A Netbios Service On A Tcp/Udp Transport: Detailed Specifications", RFC 1002, March 1987 [5] US National Bureau of Standards, "Data Encryption Standard", Federal Information Processing Standard (FIPS) Publication 46-1, January 1988 [6] Rivest, R. - MIT and RSA Data Security, Inc., "The MD4 Message Digest Algorithm", RFC 1320, April 1992 [7] X/Open Company Ltd., "X/Open CAE Specification - Protocols for X/Open PC Interworking: SMB, Version 2", X/Open Document Number: CAE 209, September 1992. 10. Security Considerations There are four authentication mechanisms, each with their own strengths and weaknesses, as well as attacks that are independent of the authentication protocol. 10.1 Share level protection In share level protection, there are no per-user passwords; knowledge of the read or write password is what gives read or write access. Since the passwords must be disclosed to be used, and hence known by many people, the scheme is quite weak. In addition, the passwords are sent in the clear over the network, so they have all the weaknesses of clear text passwords in user level security. Heizer, et al expires December 1996 [Page 216] INTERNET-DRAFT CIFS/1.0 June 1996 10.2 Plaintext Password Authentication This authentication protocol sends the client's password in the clear. It should be used only when needed for backwards compatibility, and only where the chances of eavesdropping is deemed acceptable, such as relatively isolated networks. Passwords sent to such servers should never be the same as passwords used for more secure servers. 10.3 LANMAN 2.1 (and earlier) Challenge/Response This authentication protocol is subject to the following vulnerabilities: o Known plaintext attack o Small key space o Chosen plaintext attack o Dictionary attack o Badly chosen passwords These attacks, if successful, compromise the client's password, and allow the attacker access to the client's files even after the client's session has ended. Because of these attacks, it should be used only when needed for backwards compatibility, or where the chances of eavesdropping are deemed acceptable, such as relatively isolated networks. It is more secure than plaintext password authentication, because passwords are never seen in the clear on the network. Whenever possible, the use of the NT LM 0.12 authentication is to be preferred. 10.3.1 Known Plaintext Attacks Because the challenge is plaintext, an eavesdropper can acquire known plaintext/ciphertext pairs. It can then test a guess at a password by using it to generate a key, encrypting the plaintext, and comparing it to the corresponding ciphertext. 10.3.2 Small Key Space The combination of the use of only uppercase characters, the usual user practice of choosing passwords that have alpha and perhaps numeric characters, plus the fact that the protocol treats the upper and lower halves of the 14 bytes key almost identically means that the key space is rather small. Enumerating 7 uppercase characters and digits leads to a key space of 36**7, or 78.3 billion combinations. When this mechanism was introduced nearly a decade ago, this was probably an adequately large key space, but with today's much more powerful systems, it is now Heizer, et al expires December 1996 [Page 217] INTERNET-DRAFT CIFS/1.0 June 1996 small enough to make a brute force search feasible upon a plaintext/ciphertext pair obtained via a known plaintext attack. 10.3.3 Chosen Plaintext Attacks A "main-in-the-middle" or a counterfeit server can choose the challenge "C8" which the client will then encrypt using a key derived from the client's password. The ability to choose the plaintext to be encrypted is known to make breaking many ciphers much easier. 10.3.4 Dictionary Attacks The attacker can precompute the response for many common passwords to a challenge of its choice, and build a dictionary of (response, password) pairs. It can then use the chosen plaintext attack to acquire a response corresponding to that challenge, and just look up the password in the dictionary. 10.3.5 Badly Chosen Passwords Passwords that are not long enough, or that are words in the language of the clients, make the above attacks even easier by reducing the key space even more. 10.4 NT LM 0.12 Challenge/Response Because it uses MD4 to generate the keying material from the password, and because it preserves the password's case, the key space of this protocol is essentially the full 56 bits that single DES allows; this is probably an acceptable length for most purposes (although future dialects may use triple-DES for more assurance). However, it is still subject to the same chosen plaintext and dictionary attacks as LANMAN 2.1 challenge/response if passwords are badly chosen. The only cure is to make sure that passwords are well-chosen, and long enough to have at least 56 bits of randomness. Other considerations: o Transforming the password into Unicode leaves a pattern of alternating zeros and characters in the input to MD4. This may allow MD4 to be reversed much more easily, although there is currently no known way to exploit this. o MD4 is known to be weak with respect to collisions. There may be a way to exploit this to attack its one-wayness, or to exploit the collision properties to limit key search time, although there is currently no known way to do so. Heizer, et al expires December 1996 [Page 218] INTERNET-DRAFT CIFS/1.0 June 1996 10.5 Other attacks 10.5.1 Hijack connections Any attacker that can inject packets into the network that appear to the server to be coming from a particular client, can hijack that client's connection. Once a connection is set up and the client has authenticated, subsequent packets are not authenticated, so the attacker can inject requests to read, write, or delete files to which the client has access. Doing so require that the injected packets have the right transport level sequence numbers, which can be tricky, especially if the client is sending packets at the same time. It is significantly more difficult to hijack a connection than to eavesdrop, and doing so only permits the attacker to access files as the client for the duration of the session. 10.5.2 Downgrade attack A "man-in-the-middle" can remove the bit in the SMB_COM_NEGPROT response that says the server supports challenge/response, thus fooling a client into thinking that it should supply a plaintext password. This attack can be mitigated if clients are able to be configured to require challenge/response, either in general or for particular servers. 10.5.3 Spoofing by Counterfeit Servers A counterfeit server is one that spoofs the DNS name resolution process so that the client gets the counterfeit's IP address instead of the genuine server's IP address, thus fooling the client into connecting to the counterfeit while believing it is connecting to the genuine server. Counterfeit servers are not detectable by the challenge/response authentication mechanism, which only authenticates clients. A counterfeit server can use the downgrade attack above to obtain a client's password; it can also execute a denial of service attack by denying the client's requests or returning bogus results. Counterfeit server attacks can be mitigated by deployment of DNSSEC. 10.5.4 Storing Passwords Safely The passwords used in any of the authentication mechanisms used by this protocol have to be protected from access from over the network and from physical access. If the server does not support access control at the individual file level, but only at the file tree level, then password files can not be placed in a file tree that is accessible from the network, as all files in such a tree have to be at least equally readable. Heizer, et al expires December 1996 [Page 219] INTERNET-DRAFT CIFS/1.0 June 1996 11. Author's Addresses Isaac Heizer Paul Leach Dan Perry Microsoft 1 Microsoft Way Redmond, WA 98052 isaache@microsoft.com paulle@microsoft.com danp@microsoft.com Heizer, et al expires December 1996 [Page 220] INTERNET-DRAFT CIFS/1.0 June 1996 12. Heizer, et al expires December 1996 [Page 221]