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