/* $NetBSD: in6_cksum.c,v 1.28 2011/04/25 22:05:05 yamt Exp $ */ /*- * Copyright (c) 2008 Joerg Sonnenberger <joerg@NetBSD.org>. * All rights reserved. * * 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. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 * COPYRIGHT HOLDERS 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. */ #include <sys/cdefs.h> __KERNEL_RCSID(0, "$NetBSD: in6_cksum.c,v 1.28 2011/04/25 22:05:05 yamt Exp $"); #include <sys/param.h> #include <sys/mbuf.h> #include <netinet/in.h> #include <netinet/ip6.h> /* * Checksum of the IPv6 pseudo header. * * off is supposed to be the skipped IPv6 header, len is the payload size. */ int in6_cksum(struct mbuf *m, u_int8_t nxt, uint32_t off, uint32_t len) { union { uint16_t words[16]; struct { struct in6_addr ip6_src; struct in6_addr ip6_dst; } addrs; } u; const struct in6_addr *in6_src; const struct in6_addr *in6_dst; const struct ip6_hdr *ip6; uint32_t sum; const uint16_t *w; const char *cp; if (nxt == 0) return cpu_in_cksum(m, len, off, 0); if (__predict_false(off < sizeof(struct ip6_hdr))) panic("in6_cksum: offset too short for IPv6 header"); if (__predict_false(m->m_len < sizeof(struct ip6_hdr))) panic("in6_cksum: mbuf too short for IPv6 header"); /* * Compute the equivalent of: * struct ip6_hdr_pseudo ip6; * * bzero(sizeof(*ip6)); * ip6.ip6ph_nxt = nxt; * ip6.ip6ph_len = htonl(len); * ipv6.ip6ph_src = mtod(m, struct ip6_hdr *)->ip6_src; * in6_clearscope(&ip6->ip6ph_src); * ipv6.ip6ph_dst = mtod(m, struct ip6_hdr *)->ip6_dst; * in6_clearscope(&ip6->ip6ph_dst); * sum = one_add(&ip6); */ #if BYTE_ORDER == LITTLE_ENDIAN sum = ((len & 0xffff) + ((len >> 16) & 0xffff) + nxt) << 8; #else sum = (len & 0xffff) + ((len >> 16) & 0xffff) + nxt; #endif cp = mtod(m, const char *); w = (const uint16_t *)(cp + offsetof(struct ip6_hdr, ip6_src)); ip6 = (const void *)cp; if (__predict_true((uintptr_t)w % 2 == 0)) { in6_src = &ip6->ip6_src; in6_dst = &ip6->ip6_dst; } else { memcpy(&u, &ip6->ip6_src, 32); w = u.words; in6_src = &u.addrs.ip6_src; in6_dst = &u.addrs.ip6_dst; } sum += w[0]; if (!IN6_IS_SCOPE_EMBEDDABLE(in6_src)) sum += w[1]; sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; w += 8; sum += w[0]; if (!IN6_IS_SCOPE_EMBEDDABLE(in6_dst)) sum += w[1]; sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; return cpu_in_cksum(m, len, off, sum); }