/* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */
/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 1988, 1992, 1993
* The Regents of the University of California. All rights reserved.
* Copyright (c) 1996
* Matt Thomas <matt@3am-software.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
*/
#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/systm.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <machine/in_cksum.h>
/*
* Checksum routine for Internet Protocol family headers
* (Portable Alpha version).
*
* This routine is very heavily used in the network
* code and should be modified for each CPU to be as fast as possible.
*/
#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
#define REDUCE32 \
{ \
q_util.q = sum; \
sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
}
#define REDUCE16 \
{ \
q_util.q = sum; \
l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
sum = l_util.s[0] + l_util.s[1]; \
ADDCARRY(sum); \
}
union l_util {
u_int16_t s[2];
u_int32_t l;
};
union q_util {
u_int16_t s[4];
u_int32_t l[2];
u_int64_t q;
};
u_short
in_addword(u_short a, u_short b)
{
u_int64_t sum = a + b;
ADDCARRY(sum);
return (sum);
}
static
uint64_t _do_cksum(void *addr, int len)
{
uint64_t sum;
union q_util q_util;
sum = do_cksum(addr, len);
REDUCE32;
return (sum);
}
u_short
in_cksum_skip(struct mbuf *m, int len, int skip)
{
u_int64_t sum = 0;
int mlen = 0;
int clen = 0;
caddr_t addr;
union q_util q_util;
union l_util l_util;
len -= skip;
for (; skip && m; m = m->m_next) {
if (m->m_len > skip) {
mlen = m->m_len - skip;
addr = mtod(m, caddr_t) + skip;
goto skip_start;
} else {
skip -= m->m_len;
}
}
for (; m && len; m = m->m_next) {
if (m->m_len == 0)
continue;
mlen = m->m_len;
addr = mtod(m, caddr_t);
skip_start:
if (len < mlen)
mlen = len;
if ((clen ^ (int) addr) & 1)
sum += _do_cksum(addr, mlen) << 8;
else
sum += _do_cksum(addr, mlen);
clen += mlen;
len -= mlen;
}
REDUCE16;
return (~sum & 0xffff);
}
u_int in_cksum_hdr(const struct ip *ip)
{
u_int64_t sum = do_cksum(ip, sizeof(struct ip));
union q_util q_util;
union l_util l_util;
REDUCE16;
return (~sum & 0xffff);
}
