LXR linux/include/net/sctp/checksum.h

   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, write to
  23 * the Free Software Foundation, 59 Temple Place - Suite 330,
  24 * Boston, MA 02111-1307, USA.
  25 *
  26 * Please send any bug reports or fixes you make to the
  27 * email address(es):
  28 *    lksctp developers <lksctp-developers@lists.sourceforge.net>
  29 *
  30 * Or submit a bug report through the following website:
  31 *    http://www.sf.net/projects/lksctp
  32 *
  33 * Written or modified by:
  34 *    Dinakaran Joseph
  35 *    Jon Grimm <jgrimm@us.ibm.com>
  36 *    Sridhar Samudrala <sri@us.ibm.com>
  37 *
  38 * Rewritten to use libcrc32c by:
  39 *    Vlad Yasevich <vladislav.yasevich@hp.com>
  40 *
  41 * Any bugs reported given to us we will try to fix... any fixes shared will
  42 * be incorporated into the next SCTP release.
  43 */
  44
  45#include <linux/types.h>
  46#include <net/sctp/sctp.h>
  47#include <linux/crc32c.h>
  48
  49static inline __u32 sctp_crc32c(__u32 crc, u8 *buffer, u16 length)
  50{
  51        return crc32c(crc, buffer, length);
  52}
  53
  54static inline __u32 sctp_start_cksum(__u8 *buffer, __u16 length)
  55{
  56        __u32 crc = ~(__u32)0;
  57        __u8  zero[sizeof(__u32)] = {0};
  58
  59        /* Optimize this routine to be SCTP specific, knowing how
  60         * to skip the checksum field of the SCTP header.
  61         */
  62
  63        /* Calculate CRC up to the checksum. */
  64        crc = sctp_crc32c(crc, buffer, sizeof(struct sctphdr) - sizeof(__u32));
  65
  66        /* Skip checksum field of the header. */
  67        crc = sctp_crc32c(crc, zero, sizeof(__u32));
  68
  69        /* Calculate the rest of the CRC. */
  70        crc = sctp_crc32c(crc, &buffer[sizeof(struct sctphdr)],
  71                            length - sizeof(struct sctphdr));
  72        return crc;
  73}
  74
  75static inline __u32 sctp_update_cksum(__u8 *buffer, __u16 length, __u32 crc32)
  76{
  77        return sctp_crc32c(crc32, buffer, length);
  78}
  79
  80static inline __le32 sctp_end_cksum(__be32 crc32)
  81{
  82        return cpu_to_le32(~crc32);
  83}
  84