125 lines
3.6 KiB
C
125 lines
3.6 KiB
C
/* $NetBSD: in6_cksum.c,v 1.28 2011/04/25 22:05:05 yamt Exp $ */
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/*-
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* Copyright (c) 2008 Joerg Sonnenberger <joerg@NetBSD.org>.
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* All rights reserved.
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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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*
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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
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* 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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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: in6_cksum.c,v 1.28 2011/04/25 22:05:05 yamt Exp $");
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#include <sys/param.h>
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#include <sys/mbuf.h>
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#include <netinet/in.h>
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#include <netinet/ip6.h>
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/*
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* Checksum of the IPv6 pseudo header.
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*
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* off is supposed to be the skipped IPv6 header, len is the payload size.
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*/
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int
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in6_cksum(struct mbuf *m, u_int8_t nxt, uint32_t off, uint32_t len)
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{
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union {
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uint16_t words[16];
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struct {
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struct in6_addr ip6_src;
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struct in6_addr ip6_dst;
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} addrs;
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} u;
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const struct in6_addr *in6_src;
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const struct in6_addr *in6_dst;
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const struct ip6_hdr *ip6;
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uint32_t sum;
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const uint16_t *w;
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const char *cp;
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if (nxt == 0)
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return cpu_in_cksum(m, len, off, 0);
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if (__predict_false(off < sizeof(struct ip6_hdr)))
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panic("in6_cksum: offset too short for IPv6 header");
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if (__predict_false(m->m_len < sizeof(struct ip6_hdr)))
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panic("in6_cksum: mbuf too short for IPv6 header");
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/*
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* Compute the equivalent of:
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* struct ip6_hdr_pseudo ip6;
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*
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* bzero(sizeof(*ip6));
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* ip6.ip6ph_nxt = nxt;
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* ip6.ip6ph_len = htonl(len);
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* ipv6.ip6ph_src = mtod(m, struct ip6_hdr *)->ip6_src;
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* in6_clearscope(&ip6->ip6ph_src);
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* ipv6.ip6ph_dst = mtod(m, struct ip6_hdr *)->ip6_dst;
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* in6_clearscope(&ip6->ip6ph_dst);
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* sum = one_add(&ip6);
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*/
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#if BYTE_ORDER == LITTLE_ENDIAN
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sum = ((len & 0xffff) + ((len >> 16) & 0xffff) + nxt) << 8;
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#else
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sum = (len & 0xffff) + ((len >> 16) & 0xffff) + nxt;
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#endif
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cp = mtod(m, const char *);
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w = (const uint16_t *)(cp + offsetof(struct ip6_hdr, ip6_src));
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ip6 = (const void *)cp;
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if (__predict_true((uintptr_t)w % 2 == 0)) {
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in6_src = &ip6->ip6_src;
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in6_dst = &ip6->ip6_dst;
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} else {
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memcpy(&u, &ip6->ip6_src, 32);
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w = u.words;
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in6_src = &u.addrs.ip6_src;
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in6_dst = &u.addrs.ip6_dst;
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}
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sum += w[0];
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if (!IN6_IS_SCOPE_EMBEDDABLE(in6_src))
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sum += w[1];
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sum += w[2];
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sum += w[3];
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sum += w[4];
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sum += w[5];
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sum += w[6];
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sum += w[7];
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w += 8;
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sum += w[0];
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if (!IN6_IS_SCOPE_EMBEDDABLE(in6_dst))
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sum += w[1];
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sum += w[2];
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sum += w[3];
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sum += w[4];
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sum += w[5];
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sum += w[6];
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sum += w[7];
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return cpu_in_cksum(m, len, off, sum);
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}
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