Edit File: checksum.h
/* SCTP kernel reference Implementation * Copyright (c) 1999-2001 Motorola, Inc. * Copyright (c) 2001-2003 International Business Machines, Corp. * * This file is part of the SCTP kernel reference Implementation * * SCTP Checksum functions * * The SCTP reference implementation is free software; * you can redistribute it and/or modify it under the terms of * the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * The SCTP reference implementation is distributed in the hope that it * will be useful, but WITHOUT ANY WARRANTY; without even the implied * ************************ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with GNU CC; see the file COPYING. If not, see * <http://www.gnu.org/licenses/>. * * Please send any bug reports or fixes you make to the * email address(es): * lksctp developers <lksctp-developers@lists.sourceforge.net> * * Or submit a bug report through the following website: * http://www.sf.net/projects/lksctp * * Written or modified by: * Dinakaran Joseph * Jon Grimm <jgrimm@us.ibm.com> * Sridhar Samudrala <sri@us.ibm.com> * * Rewritten to use libcrc32c by: * Vlad Yasevich <vladislav.yasevich@hp.com> * * Any bugs reported given to us we will try to fix... any fixes shared will * be incorporated into the next SCTP release. */ #ifndef __sctp_checksum_h__ #define __sctp_checksum_h__ #include <linux/types.h> #include <net/sctp/sctp.h> #include <linux/crc32c.h> #include <linux/crc32.h> static inline __wsum sctp_csum_update(const void *buff, int len, __wsum sum) { /* This uses the crypto implementation of crc32c, which is either * implemented w/ hardware support or resolves to __crc32c_le(). */ return (__force __wsum)crc32c((__force __u32)sum, buff, len); } static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2, int offset, int len) { return (__force __wsum)__crc32c_le_combine((__force __u32)csum, (__force __u32)csum2, len); } static inline __le32 sctp_compute_cksum(const struct sk_buff *skb, unsigned int offset) { struct sctphdr *sh = (struct sctphdr *)(skb->data + offset); const struct skb_checksum_ops ops = { .update = sctp_csum_update, .combine = sctp_csum_combine, }; __le32 old = sh->checksum; __wsum new; sh->checksum = 0; new = ~__skb_checksum(skb, offset, skb->len - offset, ~(__wsum)0, &ops); sh->checksum = old; return cpu_to_le32((__force __u32)new); } #endif /* __sctp_checksum_h__ */