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
31 static inline __wsum sctp_csum_update(const void *buff, int len, __wsum sum)
32 {
33 /* This uses the crypto implementation of crc32c, which is either
34 * implemented w/ hardware support or resolves to __crc32c_le().
35 */
36 return (__force __wsum)crc32c((__force __u32)sum, buff, len);
37 }
38
39 static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2,
40 int offset, int len)
41 {
42 return (__force __wsum)__crc32c_le_combine((__force __u32)csum,
43 (__force __u32)csum2, len);
44 }
45
46 static const struct skb_checksum_ops sctp_csum_ops = {
47 .update = sctp_csum_update,
48 .combine = sctp_csum_combine,
49 };
50
51 static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
52 unsigned int offset)
53 {
54 struct sctphdr *sh = (struct sctphdr *)(skb->data + offset);
55 __le32 old = sh->checksum;
56 __wsum new;
57
58 sh->checksum = 0;
59 new = ~__skb_checksum(skb, offset, skb->len - offset, ~(__wsum)0,
60 &sctp_csum_ops);
61 sh->checksum = old;
62
63 return cpu_to_le32((__force __u32)new);
64 }
65
66 #endif /* __sctp_checksum_h__ */
67
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