1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0-or-later */
2*4882a593Smuzhiyun /* SCTP kernel reference Implementation
3*4882a593Smuzhiyun * Copyright (c) 1999-2001 Motorola, Inc.
4*4882a593Smuzhiyun * Copyright (c) 2001-2003 International Business Machines, Corp.
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * This file is part of the SCTP kernel reference Implementation
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * SCTP Checksum functions
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * Please send any bug reports or fixes you make to the
11*4882a593Smuzhiyun * email address(es):
12*4882a593Smuzhiyun * lksctp developers <linux-sctp@vger.kernel.org>
13*4882a593Smuzhiyun *
14*4882a593Smuzhiyun * Written or modified by:
15*4882a593Smuzhiyun * Dinakaran Joseph
16*4882a593Smuzhiyun * Jon Grimm <jgrimm@us.ibm.com>
17*4882a593Smuzhiyun * Sridhar Samudrala <sri@us.ibm.com>
18*4882a593Smuzhiyun *
19*4882a593Smuzhiyun * Rewritten to use libcrc32c by:
20*4882a593Smuzhiyun * Vlad Yasevich <vladislav.yasevich@hp.com>
21*4882a593Smuzhiyun */
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun #ifndef __sctp_checksum_h__
24*4882a593Smuzhiyun #define __sctp_checksum_h__
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun #include <linux/types.h>
27*4882a593Smuzhiyun #include <net/sctp/sctp.h>
28*4882a593Smuzhiyun #include <linux/crc32c.h>
29*4882a593Smuzhiyun #include <linux/crc32.h>
30*4882a593Smuzhiyun
sctp_csum_update(const void * buff,int len,__wsum sum)31*4882a593Smuzhiyun static inline __wsum sctp_csum_update(const void *buff, int len, __wsum sum)
32*4882a593Smuzhiyun {
33*4882a593Smuzhiyun /* This uses the crypto implementation of crc32c, which is either
34*4882a593Smuzhiyun * implemented w/ hardware support or resolves to __crc32c_le().
35*4882a593Smuzhiyun */
36*4882a593Smuzhiyun return (__force __wsum)crc32c((__force __u32)sum, buff, len);
37*4882a593Smuzhiyun }
38*4882a593Smuzhiyun
sctp_csum_combine(__wsum csum,__wsum csum2,int offset,int len)39*4882a593Smuzhiyun static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2,
40*4882a593Smuzhiyun int offset, int len)
41*4882a593Smuzhiyun {
42*4882a593Smuzhiyun return (__force __wsum)__crc32c_le_combine((__force __u32)csum,
43*4882a593Smuzhiyun (__force __u32)csum2, len);
44*4882a593Smuzhiyun }
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun static const struct skb_checksum_ops sctp_csum_ops = {
47*4882a593Smuzhiyun .update = sctp_csum_update,
48*4882a593Smuzhiyun .combine = sctp_csum_combine,
49*4882a593Smuzhiyun };
50*4882a593Smuzhiyun
sctp_compute_cksum(const struct sk_buff * skb,unsigned int offset)51*4882a593Smuzhiyun static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
52*4882a593Smuzhiyun unsigned int offset)
53*4882a593Smuzhiyun {
54*4882a593Smuzhiyun struct sctphdr *sh = (struct sctphdr *)(skb->data + offset);
55*4882a593Smuzhiyun __le32 old = sh->checksum;
56*4882a593Smuzhiyun __wsum new;
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun sh->checksum = 0;
59*4882a593Smuzhiyun new = ~__skb_checksum(skb, offset, skb->len - offset, ~(__wsum)0,
60*4882a593Smuzhiyun &sctp_csum_ops);
61*4882a593Smuzhiyun sh->checksum = old;
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun return cpu_to_le32((__force __u32)new);
64*4882a593Smuzhiyun }
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun #endif /* __sctp_checksum_h__ */
67