Module compress 

SMB3 compression: the COMPRESSION_TRANSFORM_HEADER ([MS-SMB2] §2.2.42) and SMB2_COMPRESSION_CAPABILITIES negotiate context ([MS-SMB2] §2.2.3.1.3).

LZNT1 (compress + decompress) is delegated to the lznt1 crate; Pattern_V1 (a repeated-byte payload, §2.2.42.1) is expanded inline. Only the unchained transform form is produced; both forms are accepted on receive.

Modules

algo

Compression algorithm ids ([MS-SMB2] §2.2.3.1.3).

Constants

CAP_FLAG_CHAINED

SMB2_COMPRESSION_CAPABILITIES_FLAG_CHAINED ([MS-SMB2] §2.2.3.1.3): advertised in the negotiate context Flags field when chained compression is supported.

PROTOCOL_ID

COMPRESSION_TRANSFORM ProtocolId: 0xFC 'S' 'M' 'B'.

SUPPORTED

Algorithms this server can both send and receive.

Functions

build_compression_caps

Encode the server SMB2_COMPRESSION_CAPABILITIES context data advertising algos, setting SMB2_COMPRESSION_CAPABILITIES_FLAG_CHAINED when chained.

compress_message

Wrap msg in an unchained LZNT1 COMPRESSION_TRANSFORM. Returns None when the algorithm is unsupported or compression does not shrink the message (the caller then sends it uncompressed).

compress_message_chained

Wrap msg in a chained COMPRESSION_TRANSFORM_HEADER ([MS-SMB2] \u00a72.2.42.2), emitting a Pattern_V1 payload for each long single-byte run and an algorithm (or uncompressed NONE) payload for the data between runs ([MS-SMB2] \u00a73.1.4.4). For a READ response the SMB2 header and READ structure are carried in a leading NONE payload so only the file data is compressed. Returns None when the result would not shrink the message.

decompress_message

Decompress a whole \xFCSMB COMPRESSION_TRANSFORM frame into the original SMB2 message. None on malformed input or an unsupported algorithm.

negotiate_algos

Intersect the client’s offered algorithms with the server’s, preserving the client’s order so the negotiate response echoes the requested CompressionIds when all are supported ([MS-SMB2] §3.3.5.4).

parse_compression_caps

Parse a client SMB2_COMPRESSION_CAPABILITIES context (§2.2.3.1.3) into its advertised algorithm list.

parse_compression_flags

Read the Flags field of a client SMB2_COMPRESSION_CAPABILITIES context (§2.2.3.1.3).