1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* SCTP kernel reference Implementation
3 * Copyright (c) 1999-2001 Motorola, Inc.
4 * Copyright (c) 2001-2003 International Business Machines, Corp.
5 *
6 * This file is part of the SCTP kernel reference Implementation
7 *
8 * SCTP Checksum functions
9 *
10 * Please send any bug reports or fixes you make to the
11 * email address(es):
12 * lksctp developers <linux-sctp@vger.kernel.org>
13 *
14 * Written or modified by:
15 * Dinakaran Joseph
16 * Jon Grimm <jgrimm@us.ibm.com>
17 * Sridhar Samudrala <sri@us.ibm.com>
18 *
19 * Rewritten to use libcrc32c by:
20 * Vlad Yasevich <vladislav.yasevich@hp.com>
21 */
22
23 #ifndef __sctp_checksum_h__
24 #define __sctp_checksum_h__
25
26 #include <linux/types.h>
27 #include <linux/sctp.h>
28 #include <linux/crc32c.h>
29 #include <linux/crc32.h>
30
sctp_csum_update(const void * buff,int len,__wsum sum)31 static inline __wsum sctp_csum_update(const void *buff, int len, __wsum sum)
32 {
33 return (__force __wsum)crc32c((__force __u32)sum, buff, len);
34 }
35
sctp_csum_combine(__wsum csum,__wsum csum2,int offset,int len)36 static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2,
37 int offset, int len)
38 {
39 return (__force __wsum)crc32c_combine((__force __u32)csum,
40 (__force __u32)csum2, len);
41 }
42
43 static const struct skb_checksum_ops sctp_csum_ops = {
44 .update = sctp_csum_update,
45 .combine = sctp_csum_combine,
46 };
47
sctp_compute_cksum(const struct sk_buff * skb,unsigned int offset)48 static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
49 unsigned int offset)
50 {
51 struct sctphdr *sh = (struct sctphdr *)(skb->data + offset);
52 __le32 old = sh->checksum;
53 __wsum new;
54
55 sh->checksum = 0;
56 new = ~__skb_checksum(skb, offset, skb->len - offset, ~(__wsum)0,
57 &sctp_csum_ops);
58 sh->checksum = old;
59
60 return cpu_to_le32((__force __u32)new);
61 }
62
63 #endif /* __sctp_checksum_h__ */
64