1 /* SCTP kernel reference Implementation
2 * Copyright (c) 1999-2001 Motorola, Inc.
3 * Copyright (c) 2001-2003 International Business Machines, Corp.
4 *
5 * This file is part of the SCTP kernel reference Implementation
6 *
7 * SCTP Checksum functions
8 *
9 * The SCTP reference implementation is free software;
10 * you can redistribute it and/or modify it under the terms of
11 * the GNU General Public License as published by
12 * the Free Software Foundation; either version 2, or (at your option)
13 * any later version.
14 *
15 * The SCTP reference implementation is distributed in the hope that it
16 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
17 * ************************
18 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
19 * See the GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with GNU CC; see the file COPYING. If not, see
23 * <http://www.gnu.org/licenses/>.
24 *
25 * Please send any bug reports or fixes you make to the
26 * email address(es):
27 * lksctp developers <linux-sctp@vger.kernel.org>
28 *
29 * Written or modified by:
30 * Dinakaran Joseph
31 * Jon Grimm <jgrimm@us.ibm.com>
32 * Sridhar Samudrala <sri@us.ibm.com>
33 *
34 * Rewritten to use libcrc32c by:
35 * Vlad Yasevich <vladislav.yasevich@hp.com>
36 */
37
38 #ifndef __sctp_checksum_h__
39 #define __sctp_checksum_h__
40
41 #include <linux/types.h>
42 #include <net/sctp/sctp.h>
43 #include <linux/crc32c.h>
44 #include <linux/crc32.h>
45
sctp_csum_update(const void * buff,int len,__wsum sum)46 static inline __wsum sctp_csum_update(const void *buff, int len, __wsum sum)
47 {
48 /* This uses the crypto implementation of crc32c, which is either
49 * implemented w/ hardware support or resolves to __crc32c_le().
50 */
51 return (__force __wsum)crc32c((__force __u32)sum, buff, len);
52 }
53
sctp_csum_combine(__wsum csum,__wsum csum2,int offset,int len)54 static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2,
55 int offset, int len)
56 {
57 return (__force __wsum)__crc32c_le_combine((__force __u32)csum,
58 (__force __u32)csum2, len);
59 }
60
sctp_compute_cksum(const struct sk_buff * skb,unsigned int offset)61 static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
62 unsigned int offset)
63 {
64 struct sctphdr *sh = (struct sctphdr *)(skb->data + offset);
65 const struct skb_checksum_ops ops = {
66 .update = sctp_csum_update,
67 .combine = sctp_csum_combine,
68 };
69 __le32 old = sh->checksum;
70 __wsum new;
71
72 sh->checksum = 0;
73 new = ~__skb_checksum(skb, offset, skb->len - offset, ~(__wsum)0, &ops);
74 sh->checksum = old;
75
76 return cpu_to_le32((__force __u32)new);
77 }
78
79 #endif /* __sctp_checksum_h__ */
80