2.2.4.41.1 Request

 SMB_Parameters
   {
   UCHAR WordCount;
   Words
     {
     UCHAR    AndXCommand;
     UCHAR    AndXReserved;
     USHORT   AndXOffset;
     USHORT   Flags;
     USHORT   AccessMode;
     SMB_FILE_ATTRIBUTES SearchAttrs;
     SMB_FILE_ATTRIBUTES FileAttrs;
     UTIME    CreationTime;
     USHORT OpenMode;
     ULONG  AllocationSize;
     ULONG  Timeout;
     USHORT Reserved[2];
     }
   }
 SMB_Data
   {
   USHORT ByteCount;
   Bytes
     {
     SMB_STRING FileName;
     }
   }
            

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SMB_Parameters (31 bytes)
...
...
...																								SMB_Data (variable)
...

SMB_Parameters (31 bytes):

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WordCount								Words (30 bytes)
...
...
...

WordCount (1 byte): This field MUST be 0x0F.

Words (30 bytes):

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AndXCommand								AndXReserved								AndXOffset
Flags																AccessMode
SearchAttrs																FileAttrs
CreationTime
OpenMode																AllocationSize
...																Timeout
...																Reserved
...

AndXCommand (1 byte): The command code for the next SMB command in the packet. This value MUST be set to 0xFF if there are no additional SMB commands in the client request packet.

AndXReserved (1 byte): A reserved field. This field MUST be 0x00 when the message is sent, and the server MUST ignore this value when the message is received.

AndXOffset (2 bytes): This field MUST be set to the offset, in bytes, from the start of the SMB Header (section 2.2.3.1) to the start of the WordCount field in the next SMB command in this packet. This field is valid only if the AndXCommand field is not set to 0xFF. If AndXCommand is 0xFF, this field MUST be ignored by the server.

Flags (2 bytes): A 16-bit field of flags for requesting attribute data and locking.

Name and  bitmask	Description
REQ_ATTRIB 0x0001	If this bit is set, the client requests that the file attribute data in the response be populated. All fields after the FID in the response are also populated. If this bit is not set, all fields after the FID in the response are zero.
REQ_OPLOCK 0x0002	Client requests an exclusive OpLock on the file.
REQ _OPLOCK_BATCH 0x0004	Client requests a Batch OpLock on the file.

AccessMode (2 bytes): A 16-bit field for encoding the requested access mode. See section 3.2.4.5.1 for a discussion on sharing modes.

Name and  bitmask	Values	Meaning
AccessMode 0x0007	0	Open for reading
	1	Open for writing
	2	Open for reading and writing
	3	Open for execution
0x0008	Reserved
SharingMode 0x0070	0	Compatibility mode
	1	Deny read/write/execute to others (exclusive use requested)
	2	Deny write to others
	3	Deny read/execute to others
	4	Deny nothing to others
0x0080	Reserved
ReferenceLocality 0x0700	0	Unknown locality of reference
	1	Mainly sequential access
	2	Mainly random access
	3	Random access with some locality
	4 - 7	Undefined
0x0800	Reserved
CacheMode 0x1000	0	Perform caching on file
	1	Do not cache the file
0x2000	Reserved
WritethroughMode 0x4000	0	Write-through mode. If this flag is set, no read ahead or write behind allowed on this file or device. When the response is returned, data is expected to be on the target disk or device.
	1
0x8000	Reserved

SearchAttrs (2 bytes): The set of attributes that the file MUST have in order to be found. If none of the attribute bytes is set, the file attributes MUST refer to a regular file.<57>

FileAttrs (2 bytes): The set of attributes that the file is to have if the file needs to be created. If none of the attribute bytes is set, the file attributes MUST refer to a regular file.

CreationTime (4 bytes): A 32-bit integer time value to be assigned to the file as the time of creation if the file is created.

OpenMode (2 bytes): A 16-bit field that controls the way a file SHOULD be treated when it is opened for use by certain extended SMB requests.

Name and  bitmask	Values	Meaning
FileExistsOpts 0x0003	0	The request SHOULD fail and an error returned indicating the prior existence of the file.
	1	The file is to be appended.
	2	The file is to be truncated to zero (0) length.
	3	Reserved
CreateFile 0x0010	0	If the file does not exist, return an error.
	1	If the file does not exist, create it.

All other bits are reserved, SHOULD NOT be used by the client, and MUST be ignored by the server.

AllocationSize (4 bytes): The number of bytes to reserve on file creation or truncation. This field MAY be ignored by the server.

Timeout (4 bytes): This field is a 32-bit unsigned integer value containing the number of milliseconds to wait on a blocked open request before returning without successfully opening the file.

Reserved (4 bytes): This field is reserved and MUST be 0x00000000.

SMB_Data (variable):

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ByteCount																Bytes (variable)
...

ByteCount (2 bytes): This field MUST be greater than or equal to 0x0002.

Bytes (variable):

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FileName (variable)
...

FileName (variable): A buffer containing the name of the file to be opened.