1 /* $FreeBSD: src/sys/netinet6/in6_cksum.c,v 1.1.2.4 2003/05/06 06:46:58 suz Exp $ */ 2 /* $DragonFly: src/sys/netinet6/in6_cksum.c,v 1.4 2006/10/24 06:18:42 hsu Exp $ */ 3 /* $KAME: in6_cksum.c,v 1.10 2000/12/03 00:53:59 itojun Exp $ */ 4 5 /* 6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the project nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright (c) 1988, 1992, 1993 36 * The Regents of the University of California. All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. Neither the name of the University nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 60 * SUCH DAMAGE. 61 * 62 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 63 */ 64 65 #include <sys/param.h> 66 #include <sys/mbuf.h> 67 #include <sys/systm.h> 68 #include <netinet/in.h> 69 #include <netinet/ip6.h> 70 71 #include <net/net_osdep.h> 72 73 /* 74 * Checksum routine for Internet Protocol family headers (Portable Version). 75 * 76 * This routine is very heavily used in the network 77 * code and should be modified for each CPU to be as fast as possible. 78 */ 79 80 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 81 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} 82 83 /* 84 * m MUST contain a continuous IP6 header. 85 * off is a offset where TCP/UDP/ICMP6 header starts. 86 * len is a total length of a transport segment. 87 * (e.g. TCP header + TCP payload) 88 */ 89 90 int 91 in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len) 92 { 93 u_int16_t *w; 94 int sum = 0; 95 int mlen = 0; 96 int byte_swapped = 0; 97 struct ip6_hdr *ip6; 98 union { 99 u_int16_t phs[4]; 100 struct { 101 u_int32_t ph_len; 102 u_int8_t ph_zero[3]; 103 u_int8_t ph_nxt; 104 } ph __attribute__((__packed__)); 105 } uph; 106 union { 107 u_int8_t c[2]; 108 u_int16_t s; 109 } s_util; 110 union { 111 u_int16_t s[2]; 112 u_int32_t l; 113 } l_util; 114 115 /* sanity check */ 116 if (m->m_pkthdr.len < off + len) { 117 panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)", 118 m->m_pkthdr.len, off, len); 119 } 120 121 bzero(&uph, sizeof(uph)); 122 123 /* 124 * First create IP6 pseudo header and calculate a summary. 125 */ 126 ip6 = mtod(m, struct ip6_hdr *); 127 w = (u_int16_t *)&ip6->ip6_src; 128 uph.ph.ph_len = htonl(len); 129 uph.ph.ph_nxt = nxt; 130 131 /* IPv6 source address */ 132 sum += w[0]; 133 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 134 sum += w[1]; 135 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; 136 sum += w[6]; sum += w[7]; 137 /* IPv6 destination address */ 138 sum += w[8]; 139 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 140 sum += w[9]; 141 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; 142 sum += w[14]; sum += w[15]; 143 /* Payload length and upper layer identifier */ 144 sum += uph.phs[0]; sum += uph.phs[1]; 145 sum += uph.phs[2]; sum += uph.phs[3]; 146 147 /* 148 * Secondly calculate a summary of the first mbuf excluding offset. 149 */ 150 while (m != NULL && off > 0) { 151 if (m->m_len <= off) 152 off -= m->m_len; 153 else 154 break; 155 m = m->m_next; 156 } 157 w = (u_int16_t *)(mtod(m, u_char *) + off); 158 mlen = m->m_len - off; 159 if (len < mlen) 160 mlen = len; 161 len -= mlen; 162 /* 163 * Force to even boundary. 164 */ 165 if ((1 & (long) w) && (mlen > 0)) { 166 REDUCE; 167 sum <<= 8; 168 s_util.c[0] = *(u_char *)w; 169 w = (u_int16_t *)((char *)w + 1); 170 mlen--; 171 byte_swapped = 1; 172 } 173 /* 174 * Unroll the loop to make overhead from 175 * branches &c small. 176 */ 177 while ((mlen -= 32) >= 0) { 178 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 179 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 180 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 181 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 182 w += 16; 183 } 184 mlen += 32; 185 while ((mlen -= 8) >= 0) { 186 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 187 w += 4; 188 } 189 mlen += 8; 190 if (mlen == 0 && byte_swapped == 0) 191 goto next; 192 REDUCE; 193 while ((mlen -= 2) >= 0) { 194 sum += *w++; 195 } 196 if (byte_swapped) { 197 REDUCE; 198 sum <<= 8; 199 byte_swapped = 0; 200 if (mlen == -1) { 201 s_util.c[1] = *(char *)w; 202 sum += s_util.s; 203 mlen = 0; 204 } else 205 mlen = -1; 206 } else if (mlen == -1) 207 s_util.c[0] = *(char *)w; 208 next: 209 m = m->m_next; 210 211 /* 212 * Lastly calculate a summary of the rest of mbufs. 213 */ 214 215 for (;m && len; m = m->m_next) { 216 if (m->m_len == 0) 217 continue; 218 w = mtod(m, u_int16_t *); 219 if (mlen == -1) { 220 /* 221 * The first byte of this mbuf is the continuation 222 * of a word spanning between this mbuf and the 223 * last mbuf. 224 * 225 * s_util.c[0] is already saved when scanning previous 226 * mbuf. 227 */ 228 s_util.c[1] = *(char *)w; 229 sum += s_util.s; 230 w = (u_int16_t *)((char *)w + 1); 231 mlen = m->m_len - 1; 232 len--; 233 } else 234 mlen = m->m_len; 235 if (len < mlen) 236 mlen = len; 237 len -= mlen; 238 /* 239 * Force to even boundary. 240 */ 241 if ((1 & (long) w) && (mlen > 0)) { 242 REDUCE; 243 sum <<= 8; 244 s_util.c[0] = *(u_char *)w; 245 w = (u_int16_t *)((char *)w + 1); 246 mlen--; 247 byte_swapped = 1; 248 } 249 /* 250 * Unroll the loop to make overhead from 251 * branches &c small. 252 */ 253 while ((mlen -= 32) >= 0) { 254 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 255 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 256 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 257 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 258 w += 16; 259 } 260 mlen += 32; 261 while ((mlen -= 8) >= 0) { 262 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 263 w += 4; 264 } 265 mlen += 8; 266 if (mlen == 0 && byte_swapped == 0) 267 continue; 268 REDUCE; 269 while ((mlen -= 2) >= 0) { 270 sum += *w++; 271 } 272 if (byte_swapped) { 273 REDUCE; 274 sum <<= 8; 275 byte_swapped = 0; 276 if (mlen == -1) { 277 s_util.c[1] = *(char *)w; 278 sum += s_util.s; 279 mlen = 0; 280 } else 281 mlen = -1; 282 } else if (mlen == -1) 283 s_util.c[0] = *(char *)w; 284 } 285 if (len) 286 panic("in6_cksum: out of data"); 287 if (mlen == -1) { 288 /* The last mbuf has odd # of bytes. Follow the 289 standard (the odd byte may be shifted left by 8 bits 290 or not as determined by endian-ness of the machine) */ 291 s_util.c[1] = 0; 292 sum += s_util.s; 293 } 294 REDUCE; 295 return (~sum & 0xffff); 296 } 297