1/* $FreeBSD: src/sys/netinet6/in6_cksum.c,v 1.1.2.3 2001/07/03 11:01:52 ume Exp $ */ 2/* $KAME: in6_cksum.c,v 1.10 2000/12/03 00:53:59 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. All advertising materials mentioning features or use of this software 46 * must display the following acknowledgement: 47 * This product includes software developed by the University of 48 * California, Berkeley and its contributors. 49 * 4. Neither the name of the University nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 63 * SUCH DAMAGE. 64 * 65 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 66 */ 67 68#include <sys/param.h> 69#include <sys/mbuf.h> 70#include <sys/systm.h> 71#include <kern/debug.h> 72#include <netinet/in.h> 73#include <netinet/ip6.h> 74 75#include <net/net_osdep.h> 76 77/* 78 * Checksum routine for Internet Protocol family headers (Portable Version). 79 * 80 * This routine is very heavily used in the network 81 * code and should be modified for each CPU to be as fast as possible. 82 */ 83 84#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 85#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} 86 87/* 88 * m MUST contain a continuous IP6 header. 89 * off is a offset where TCP/UDP/ICMP6 header starts. 90 * len is a total length of a transport segment. 91 * (e.g. TCP header + TCP payload) 92 */ 93 94u_int16_t 95inet6_cksum(struct mbuf *m, unsigned int nxt, unsigned int off, 96 unsigned int len) 97{ 98 u_int16_t *w; 99 int sum = 0; 100 int mlen = 0; 101 int byte_swapped = 0; 102 struct ip6_hdr *ip6; 103 union { 104 u_int16_t phs[4]; 105 struct { 106 u_int32_t ph_len; 107 u_int8_t ph_zero[3]; 108 u_int8_t ph_nxt; 109 } ph __attribute__((__packed__)); 110 } uph; 111 union { 112 u_int8_t c[2]; 113 u_int16_t s; 114 } s_util; 115 union { 116 u_int16_t s[2]; 117 u_int32_t l; 118 } l_util; 119 120 /* sanity check */ 121 if (m->m_pkthdr.len < off + len) { 122 panic("inet6_cksum: mbuf len (%d) < off+len (%d+%d)\n", 123 m->m_pkthdr.len, off, len); 124 } 125 126 if (nxt != 0) { 127 bzero(&uph, sizeof (uph)); 128 129 /* 130 * First create IP6 pseudo header and calculate a summary. 131 */ 132 ip6 = mtod(m, struct ip6_hdr *); 133 w = (u_int16_t *)&ip6->ip6_src; 134 uph.ph.ph_len = htonl(len); 135 uph.ph.ph_nxt = nxt; 136 137 /* IPv6 source address */ 138 sum += w[0]; 139 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 140 sum += w[1]; 141 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; 142 sum += w[6]; sum += w[7]; 143 /* IPv6 destination address */ 144 sum += w[8]; 145 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 146 sum += w[9]; 147 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; 148 sum += w[14]; sum += w[15]; 149 /* Payload length and upper layer identifier */ 150 sum += uph.phs[0]; sum += uph.phs[1]; 151 sum += uph.phs[2]; sum += uph.phs[3]; 152 } 153 154 /* 155 * Secondly calculate a summary of the first mbuf excluding offset. 156 */ 157 while (m != NULL && off > 0) { 158 if (m->m_len <= off) 159 off -= m->m_len; 160 else 161 break; 162 m = m->m_next; 163 } 164 w = (u_int16_t *)(mtod(m, u_char *) + off); 165 mlen = m->m_len - off; 166 if (len < mlen) 167 mlen = len; 168 len -= mlen; 169 /* 170 * Force to even boundary. 171 */ 172 if ((1 & (long) w) && (mlen > 0)) { 173 REDUCE; 174 sum <<= 8; 175 s_util.c[0] = *(u_char *)w; 176 w = (u_int16_t *)((char *)w + 1); 177 mlen--; 178 byte_swapped = 1; 179 } 180 /* 181 * Unroll the loop to make overhead from 182 * branches &c small. 183 */ 184 while ((mlen -= 32) >= 0) { 185 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 186 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 187 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 188 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 189 w += 16; 190 } 191 mlen += 32; 192 while ((mlen -= 8) >= 0) { 193 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 194 w += 4; 195 } 196 mlen += 8; 197 if (mlen == 0 && byte_swapped == 0) 198 goto next; 199 REDUCE; 200 while ((mlen -= 2) >= 0) { 201 sum += *w++; 202 } 203 if (byte_swapped) { 204 REDUCE; 205 sum <<= 8; 206 byte_swapped = 0; 207 if (mlen == -1) { 208 s_util.c[1] = *(char *)w; 209 sum += s_util.s; 210 mlen = 0; 211 } else 212 mlen = -1; 213 } else if (mlen == -1) 214 s_util.c[0] = *(char *)w; 215 next: 216 m = m->m_next; 217 218 /* 219 * Lastly calculate a summary of the rest of mbufs. 220 */ 221 222 for (;m && len; m = m->m_next) { 223 if (m->m_len == 0) 224 continue; 225 w = mtod(m, u_int16_t *); 226 if (mlen == -1) { 227 /* 228 * The first byte of this mbuf is the continuation 229 * of a word spanning between this mbuf and the 230 * last mbuf. 231 * 232 * s_util.c[0] is already saved when scanning previous 233 * mbuf. 234 */ 235 s_util.c[1] = *(char *)w; 236 sum += s_util.s; 237 w = (u_int16_t *)((char *)w + 1); 238 mlen = m->m_len - 1; 239 len--; 240 } else 241 mlen = m->m_len; 242 if (len < mlen) 243 mlen = len; 244 len -= mlen; 245 /* 246 * Force to even boundary. 247 */ 248 if ((1 & (long) w) && (mlen > 0)) { 249 REDUCE; 250 sum <<= 8; 251 s_util.c[0] = *(u_char *)w; 252 w = (u_int16_t *)((char *)w + 1); 253 mlen--; 254 byte_swapped = 1; 255 } 256 /* 257 * Unroll the loop to make overhead from 258 * branches &c small. 259 */ 260 while ((mlen -= 32) >= 0) { 261 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 262 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 263 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 264 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 265 w += 16; 266 } 267 mlen += 32; 268 while ((mlen -= 8) >= 0) { 269 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 270 w += 4; 271 } 272 mlen += 8; 273 if (mlen == 0 && byte_swapped == 0) 274 continue; 275 REDUCE; 276 while ((mlen -= 2) >= 0) { 277 sum += *w++; 278 } 279 if (byte_swapped) { 280 REDUCE; 281 sum <<= 8; 282 byte_swapped = 0; 283 if (mlen == -1) { 284 s_util.c[1] = *(char *)w; 285 sum += s_util.s; 286 mlen = 0; 287 } else 288 mlen = -1; 289 } else if (mlen == -1) 290 s_util.c[0] = *(char *)w; 291 } 292 if (len) 293 printf("inet6_cksum: out of data by %d\n", len); 294 if (mlen == -1) { 295 /* The last mbuf has odd # of bytes. Follow the 296 standard (the odd byte may be shifted left by 8 bits 297 or not as determined by endian-ness of the machine) */ 298 s_util.c[1] = 0; 299 sum += s_util.s; 300 } 301 REDUCE; 302 return (~sum & 0xffff); 303} 304