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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * Copyright (C) 2024, SUSE LLC4 *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 details12 * MS-SMB2 "3.1.5.3 Decompressing the Chained Message" - for decompression details13 * MS-XCA - for details of the supported algorithms14 */15#ifndef _SMB_COMPRESS_H16#define _SMB_COMPRESS_H17 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 1625/* sizeof(smb2_compression_payload_hdr) - sizeof(OriginalPayloadSize) */26#define SMB_COMPRESS_PAYLOAD_HDR_LEN 827#define SMB_COMPRESS_MIN_LEN PAGE_SIZE28 29#ifdef CONFIG_CIFS_COMPRESSION30typedef int (*compress_send_fn)(struct TCP_Server_Info *, int, struct smb_rqst *);31 32int smb_compress(struct TCP_Server_Info *server, struct smb_rqst *rq, compress_send_fn send_fn);33 34/**35 * should_compress() - Determines if a request (write) or the response to a36 * request (read) should be compressed.37 * @tcon: tcon of the request is being sent to38 * @rqst: request to evaluate39 *40 * Return: true iff:41 * - compression was successfully negotiated with server42 * - server has enabled compression for the share43 * - it's a read or write request44 * - (write only) request length is >= SMB_COMPRESS_MIN_LEN45 * - (write only) is_compressible() returns 146 *47 * Return false otherwise.48 */49bool should_compress(const struct cifs_tcon *tcon, const struct smb_rqst *rq);50 51/**52 * smb_compress_alg_valid() - Validate a compression algorithm.53 * @alg: Compression algorithm to check.54 * @valid_none: Conditional check whether NONE algorithm should be55 * considered valid or not.56 *57 * If @alg is SMB3_COMPRESS_NONE, this function returns @valid_none.58 *59 * Note that 'NONE' (0) compressor type is considered invalid in protocol60 * negotiation, as it's never requested to/returned from the server.61 *62 * Return: true if @alg is valid/supported, false otherwise.63 */64static __always_inline int smb_compress_alg_valid(__le16 alg, bool valid_none)65{66 if (alg == SMB3_COMPRESS_NONE)67 return valid_none;68 69 if (alg == SMB3_COMPRESS_LZ77 || alg == SMB3_COMPRESS_PATTERN)70 return true;71 72 return false;73}74#else /* !CONFIG_CIFS_COMPRESSION */75static inline int smb_compress(void *unused1, void *unused2, void *unused3)76{77 return -EOPNOTSUPP;78}79 80static inline bool should_compress(void *unused1, void *unused2)81{82 return false;83}84 85static inline int smb_compress_alg_valid(__le16 unused1, bool unused2)86{87 return -EOPNOTSUPP;88}89#endif /* !CONFIG_CIFS_COMPRESSION */90#endif /* _SMB_COMPRESS_H */91