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 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 crc32c(sum, buff, len); 52 } 53 54 static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2, 55 int offset, int len) 56 { 57 return __crc32c_le_combine(csum, csum2, len); 58 } 59 60 static inline __le32 sctp_compute_cksum(const struct sk_buff *skb, 61 unsigned int offset) 62 { 63 struct sctphdr *sh = sctp_hdr(skb); 64 __le32 ret, old = sh->checksum; 65 const struct skb_checksum_ops ops = { 66 .update = sctp_csum_update, 67 .combine = sctp_csum_combine, 68 }; 69 70 sh->checksum = 0; 71 ret = cpu_to_le32(~__skb_checksum(skb, offset, skb->len - offset, 72 ~(__u32)0, &ops)); 73 sh->checksum = old; 74 75 return ret; 76 } 77 78 #endif /* __sctp_checksum_h__ */ 79