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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 <net/sctp/sctp.h>
28#include <linux/crc32c.h>
29#include <linux/crc32.h>
30
31static 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
39static 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
46static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
47 unsigned int offset)
48{
49 struct sctphdr *sh = (struct sctphdr *)(skb->data + offset);
50 const struct skb_checksum_ops ops = {
51 .update = sctp_csum_update,
52 .combine = sctp_csum_combine,
53 };
54 __le32 old = sh->checksum;
55 __wsum new;
56
57 sh->checksum = 0;
58 new = ~__skb_checksum(skb, offset, skb->len - offset, ~(__wsum)0, &ops);
59 sh->checksum = old;
60
61 return cpu_to_le32((__force __u32)new);
62}
63
64#endif /* __sctp_checksum_h__ */