in6_cksum.c revision 1.22
1 /* $NetBSD: in6_cksum.c,v 1.22 2008/01/25 21:12:15 joerg Exp $ */ 2 /* $KAME: in6_cksum.c,v 1.9 2000/09/09 15:33:31 itojun Exp $ */ 3 4 /* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 /* 34 * Copyright (c) 1988, 1992, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 1. Redistributions of source code must retain the above copyright 41 * notice, this list of conditions and the following disclaimer. 42 * 2. Redistributions in binary form must reproduce the above copyright 43 * notice, this list of conditions and the following disclaimer in the 44 * documentation and/or other materials provided with the distribution. 45 * 3. Neither the name of the University nor the names of its contributors 46 * may be used to endorse or promote products derived from this software 47 * without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59 * SUCH DAMAGE. 60 * 61 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 62 */ 63 64 #include <sys/cdefs.h> 65 __KERNEL_RCSID(0, "$NetBSD: in6_cksum.c,v 1.22 2008/01/25 21:12:15 joerg Exp $"); 66 67 #include <sys/param.h> 68 #include <sys/mbuf.h> 69 #include <sys/systm.h> 70 #include <netinet/in.h> 71 #include <netinet/ip6.h> 72 #include <netinet6/scope6_var.h> 73 74 #include <net/net_osdep.h> 75 76 /* 77 * Checksum routine for Internet Protocol family headers (Portable Version). 78 * 79 * This routine is very heavily used in the network 80 * code and should be modified for each CPU to be as fast as possible. 81 */ 82 83 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 84 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} 85 86 /* 87 * m MUST contain a continuous IP6 header. 88 * off is a offset where TCP/UDP/ICMP6 header starts. 89 * len is a total length of a transport segment. 90 * (e.g. TCP header + TCP payload) 91 */ 92 93 int 94 in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len) 95 { 96 u_int16_t *w; 97 uint32_t sum = 0; 98 struct ip6_hdr *ip6; 99 struct in6_addr in6; 100 union { 101 u_int16_t phs[4]; 102 struct { 103 u_int32_t ph_len; 104 u_int8_t ph_zero[3]; 105 u_int8_t ph_nxt; 106 } ph __packed; 107 } uph; 108 109 /* sanity check */ 110 if (m->m_pkthdr.len < off + len) { 111 panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)", 112 m->m_pkthdr.len, off, len); 113 } 114 115 /* Skip pseudo-header if nxt == 0. */ 116 if (nxt == 0) 117 goto skip_phdr; 118 119 bzero(&uph, sizeof(uph)); 120 121 /* 122 * First create IP6 pseudo header and calculate a summary. 123 */ 124 ip6 = mtod(m, struct ip6_hdr *); 125 w = (u_int16_t *)&ip6->ip6_src; 126 uph.ph.ph_len = htonl(len); 127 uph.ph.ph_nxt = nxt; 128 129 /* 130 * IPv6 source address 131 * XXX: we'd like to avoid copying the address, but we can't due to 132 * the possibly embedded scope zone ID. 133 */ 134 in6 = ip6->ip6_src; 135 in6_clearscope(&in6); 136 w = (u_int16_t *)&in6; 137 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 138 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 139 140 /* IPv6 destination address */ 141 in6 = ip6->ip6_dst; 142 in6_clearscope(&in6); 143 w = (u_int16_t *)&in6; 144 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 145 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 146 147 /* Payload length and upper layer identifier */ 148 sum += uph.phs[0]; sum += uph.phs[1]; 149 sum += uph.phs[2]; sum += uph.phs[3]; 150 151 skip_phdr: 152 return cpu_in_cksum(m, len, off, sum); 153 } 154
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