/* 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, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <[email protected]>
*
* Written or modified by:
* Dinakaran Joseph
* Jon Grimm <[email protected]>
* Sridhar Samudrala <[email protected]>
*
* Rewritten to use libcrc32c by:
* Vlad Yasevich <[email protected]>
*/

#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 crc32c(sum, buff, len);
}

static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2,
int offset, int len)
{
return __crc32c_le_combine(csum, csum2, len);
}

static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
unsigned int offset)
{
struct sctphdr *sh = sctp_hdr(skb);
__le32 ret, old = sh->checksum;
const struct skb_checksum_ops ops = {
.update = sctp_csum_update,
.combine = sctp_csum_combine,
};

sh->checksum = 0;
ret = cpu_to_le32(~__skb_checksum(skb, offset, skb->len - offset,
~(__u32)0, &ops));
sh->checksum = old;

return ret;
}

#endif /* __sctp_checksum_h__ */