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. All advertising materials mentioning features or use of this software 47 * must display the following acknowledgement: 48 * This product includes software developed by the University of 49 * California, Berkeley and its contributors. 50 * 4. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 67 */ 68 69 #include <sys/param.h> 70 #include <sys/mbuf.h> 71 #include <sys/systm.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 94 int 95 in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len) 96 { 97 u_int16_t *w; 98 int sum = 0; 99 int mlen = 0; 100 int byte_swapped = 0; 101 #if 0 102 int srcifid = 0, dstifid = 0; 103 #endif 104 struct ip6_hdr *ip6; 105 union { 106 u_int16_t phs[4]; 107 struct { 108 u_int32_t ph_len; 109 u_int8_t ph_zero[3]; 110 u_int8_t ph_nxt; 111 } ph __attribute__((__packed__)); 112 } uph; 113 union { 114 u_int8_t c[2]; 115 u_int16_t s; 116 } s_util; 117 union { 118 u_int16_t s[2]; 119 u_int32_t l; 120 } l_util; 121 122 /* sanity check */ 123 if (m->m_pkthdr.len < off + len) { 124 panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)", 125 m->m_pkthdr.len, off, len); 126 } 127 128 bzero(&uph, sizeof(uph)); 129 130 /* 131 * First create IP6 pseudo header and calculate a summary. 132 */ 133 ip6 = mtod(m, struct ip6_hdr *); 134 #if 0 135 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { 136 srcifid = ip6->ip6_src.s6_addr16[1]; 137 ip6->ip6_src.s6_addr16[1] = 0; 138 } 139 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { 140 dstifid = ip6->ip6_dst.s6_addr16[1]; 141 ip6->ip6_dst.s6_addr16[1] = 0; 142 } 143 #endif 144 w = (u_int16_t *)&ip6->ip6_src; 145 uph.ph.ph_len = htonl(len); 146 uph.ph.ph_nxt = nxt; 147 148 /* IPv6 source address */ 149 sum += w[0]; 150 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 151 sum += w[1]; 152 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; 153 sum += w[6]; sum += w[7]; 154 /* IPv6 destination address */ 155 sum += w[8]; 156 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 157 sum += w[9]; 158 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; 159 sum += w[14]; sum += w[15]; 160 /* Payload length and upper layer identifier */ 161 sum += uph.phs[0]; sum += uph.phs[1]; 162 sum += uph.phs[2]; sum += uph.phs[3]; 163 164 #if 0 165 if (srcifid) 166 ip6->ip6_src.s6_addr16[1] = srcifid; 167 if (dstifid) 168 ip6->ip6_dst.s6_addr16[1] = dstifid; 169 #endif 170 /* 171 * Secondly calculate a summary of the first mbuf excluding offset. 172 */ 173 while (m != NULL && off > 0) { 174 if (m->m_len <= off) 175 off -= m->m_len; 176 else 177 break; 178 m = m->m_next; 179 } 180 w = (u_int16_t *)(mtod(m, u_char *) + off); 181 mlen = m->m_len - off; 182 if (len < mlen) 183 mlen = len; 184 len -= mlen; 185 /* 186 * Force to even boundary. 187 */ 188 if ((1 & (long) w) && (mlen > 0)) { 189 REDUCE; 190 sum <<= 8; 191 s_util.c[0] = *(u_char *)w; 192 w = (u_int16_t *)((char *)w + 1); 193 mlen--; 194 byte_swapped = 1; 195 } 196 /* 197 * Unroll the loop to make overhead from 198 * branches &c small. 199 */ 200 while ((mlen -= 32) >= 0) { 201 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 202 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 203 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 204 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 205 w += 16; 206 } 207 mlen += 32; 208 while ((mlen -= 8) >= 0) { 209 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 210 w += 4; 211 } 212 mlen += 8; 213 if (mlen == 0 && byte_swapped == 0) 214 goto next; 215 REDUCE; 216 while ((mlen -= 2) >= 0) { 217 sum += *w++; 218 } 219 if (byte_swapped) { 220 REDUCE; 221 sum <<= 8; 222 byte_swapped = 0; 223 if (mlen == -1) { 224 s_util.c[1] = *(char *)w; 225 sum += s_util.s; 226 mlen = 0; 227 } else 228 mlen = -1; 229 } else if (mlen == -1) 230 s_util.c[0] = *(char *)w; 231 next: 232 m = m->m_next; 233 234 /* 235 * Lastly calculate a summary of the rest of mbufs. 236 */ 237 238 for (;m && len; m = m->m_next) { 239 if (m->m_len == 0) 240 continue; 241 w = mtod(m, u_int16_t *); 242 if (mlen == -1) { 243 /* 244 * The first byte of this mbuf is the continuation 245 * of a word spanning between this mbuf and the 246 * last mbuf. 247 * 248 * s_util.c[0] is already saved when scanning previous 249 * mbuf. 250 */ 251 s_util.c[1] = *(char *)w; 252 sum += s_util.s; 253 w = (u_int16_t *)((char *)w + 1); 254 mlen = m->m_len - 1; 255 len--; 256 } else 257 mlen = m->m_len; 258 if (len < mlen) 259 mlen = len; 260 len -= mlen; 261 /* 262 * Force to even boundary. 263 */ 264 if ((1 & (long) w) && (mlen > 0)) { 265 REDUCE; 266 sum <<= 8; 267 s_util.c[0] = *(u_char *)w; 268 w = (u_int16_t *)((char *)w + 1); 269 mlen--; 270 byte_swapped = 1; 271 } 272 /* 273 * Unroll the loop to make overhead from 274 * branches &c small. 275 */ 276 while ((mlen -= 32) >= 0) { 277 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 278 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 279 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 280 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 281 w += 16; 282 } 283 mlen += 32; 284 while ((mlen -= 8) >= 0) { 285 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 286 w += 4; 287 } 288 mlen += 8; 289 if (mlen == 0 && byte_swapped == 0) 290 continue; 291 REDUCE; 292 while ((mlen -= 2) >= 0) { 293 sum += *w++; 294 } 295 if (byte_swapped) { 296 REDUCE; 297 sum <<= 8; 298 byte_swapped = 0; 299 if (mlen == -1) { 300 s_util.c[1] = *(char *)w; 301 sum += s_util.s; 302 mlen = 0; 303 } else 304 mlen = -1; 305 } else if (mlen == -1) 306 s_util.c[0] = *(char *)w; 307 } 308 if (len) 309 panic("in6_cksum: out of data"); 310 if (mlen == -1) { 311 /* The last mbuf has odd # of bytes. Follow the 312 standard (the odd byte may be shifted left by 8 bits 313 or not as determined by endian-ness of the machine) */ 314 s_util.c[1] = 0; 315 sum += s_util.s; 316 } 317 REDUCE; 318 return (~sum & 0xffff); 319 } 320