1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (C) 2024, SUSE LLC 4 * 5 * Authors: Enzo Matsumiya <ematsumiya@suse.de> 6 * 7 * This file implements I/O compression support for SMB2 messages (SMB 3.1.1 only). 8 * See compress/ for implementation details of each algorithm. 9 * 10 * References: 11 * MS-SMB2 "3.1.4.4 Compressing the Message" - for compression details 12 * MS-SMB2 "3.1.5.3 Decompressing the Chained Message" - for decompression details 13 * MS-XCA - for details of the supported algorithms 14 */ 15 #ifndef _SMB_COMPRESS_H 16 #define _SMB_COMPRESS_H 17 18 #include <linux/uio.h> 19 #include <linux/kernel.h> 20 #include "../common/smb2pdu.h" 21 #include "cifsglob.h" 22 23 /* sizeof(smb2_compression_hdr) - sizeof(OriginalPayloadSize) */ 24 #define SMB_COMPRESS_HDR_LEN 16 25 /* sizeof(smb2_compression_payload_hdr) - sizeof(OriginalPayloadSize) */ 26 #define SMB_COMPRESS_PAYLOAD_HDR_LEN 8 27 #define SMB_COMPRESS_MIN_LEN PAGE_SIZE 28 29 #ifdef CONFIG_CIFS_COMPRESSION 30 typedef int (*compress_send_fn)(struct TCP_Server_Info *, int, struct smb_rqst *); 31 32 33 int smb_compress(struct TCP_Server_Info *server, struct smb_rqst *rq, 34 compress_send_fn send_fn); 35 bool should_compress(const struct cifs_tcon *tcon, const struct smb_rqst *rq); 36 37 /* 38 * smb_compress_alg_valid() - Validate a compression algorithm. 39 * @alg: Compression algorithm to check. 40 * @valid_none: Conditional check whether NONE algorithm should be 41 * considered valid or not. 42 * 43 * If @alg is SMB3_COMPRESS_NONE, this function returns @valid_none. 44 * 45 * Note that 'NONE' (0) compressor type is considered invalid in protocol 46 * negotiation, as it's never requested to/returned from the server. 47 * 48 * Return: true if @alg is valid/supported, false otherwise. 49 */ 50 static __always_inline int smb_compress_alg_valid(__le16 alg, bool valid_none) 51 { 52 if (alg == SMB3_COMPRESS_NONE) 53 return valid_none; 54 55 if (alg == SMB3_COMPRESS_LZ77 || alg == SMB3_COMPRESS_PATTERN) 56 return true; 57 58 return false; 59 } 60 #else /* !CONFIG_CIFS_COMPRESSION */ 61 static inline int smb_compress(void *unused1, void *unused2, void *unused3) 62 { 63 return -EOPNOTSUPP; 64 } 65 66 static inline bool should_compress(void *unused1, void *unused2) 67 { 68 return false; 69 } 70 71 static inline int smb_compress_alg_valid(__le16 unused1, bool unused2) 72 { 73 return -EOPNOTSUPP; 74 } 75 #endif /* !CONFIG_CIFS_COMPRESSION */ 76 #endif /* _SMB_COMPRESS_H */ 77