in6_cksum.c revision 1.11
1 /* $NetBSD: in6_cksum.c,v 1.11 2001/05/30 03:06:56 thorpej 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. 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 <netinet/in.h> 72 #include <netinet/ip6.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(m, nxt, off, len) 95 struct mbuf *m; 96 u_int8_t nxt; 97 u_int32_t off, len; 98 { 99 u_int16_t *w; 100 int sum = 0; 101 int mlen = 0; 102 int byte_swapped = 0; 103 #if 0 104 int srcifid = 0, dstifid = 0; 105 #endif 106 struct ip6_hdr *ip6; 107 union { 108 u_int16_t phs[4]; 109 struct { 110 u_int32_t ph_len; 111 u_int8_t ph_zero[3]; 112 u_int8_t ph_nxt; 113 } ph __attribute__((__packed__)); 114 } uph; 115 union { 116 u_int8_t c[2]; 117 u_int16_t s; 118 } s_util; 119 union { 120 u_int16_t s[2]; 121 u_int32_t l; 122 } l_util; 123 124 /* sanity check */ 125 if (m->m_pkthdr.len < off + len) { 126 panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)\n", 127 m->m_pkthdr.len, off, len); 128 } 129 130 /* Skip pseudo-header if nxt == 0. */ 131 if (nxt == 0) 132 goto skip_phdr; 133 134 bzero(&uph, sizeof(uph)); 135 136 /* 137 * First create IP6 pseudo header and calculate a summary. 138 */ 139 ip6 = mtod(m, struct ip6_hdr *); 140 #if 0 141 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { 142 srcifid = ip6->ip6_src.s6_addr16[1]; 143 ip6->ip6_src.s6_addr16[1] = 0; 144 } 145 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { 146 dstifid = ip6->ip6_dst.s6_addr16[1]; 147 ip6->ip6_dst.s6_addr16[1] = 0; 148 } 149 #endif 150 w = (u_int16_t *)&ip6->ip6_src; 151 uph.ph.ph_len = htonl(len); 152 uph.ph.ph_nxt = nxt; 153 154 /* IPv6 source address */ 155 sum += w[0]; 156 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 157 sum += w[1]; 158 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; 159 sum += w[6]; sum += w[7]; 160 /* IPv6 destination address */ 161 sum += w[8]; 162 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 163 sum += w[9]; 164 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; 165 sum += w[14]; sum += w[15]; 166 /* Payload length and upper layer identifier */ 167 sum += uph.phs[0]; sum += uph.phs[1]; 168 sum += uph.phs[2]; sum += uph.phs[3]; 169 170 #if 0 171 if (srcifid) 172 ip6->ip6_src.s6_addr16[1] = srcifid; 173 if (dstifid) 174 ip6->ip6_dst.s6_addr16[1] = dstifid; 175 #endif 176 skip_phdr: 177 /* 178 * Secondly calculate a summary of the first mbuf excluding offset. 179 */ 180 while (m != NULL && off > 0) { 181 if (m->m_len <= off) 182 off -= m->m_len; 183 else 184 break; 185 m = m->m_next; 186 } 187 w = (u_int16_t *)(mtod(m, u_char *) + off); 188 mlen = m->m_len - off; 189 if (len < mlen) 190 mlen = len; 191 len -= mlen; 192 /* 193 * Force to even boundary. 194 */ 195 if ((1 & (long) w) && (mlen > 0)) { 196 REDUCE; 197 sum <<= 8; 198 s_util.c[0] = *(u_char *)w; 199 w = (u_int16_t *)((char *)w + 1); 200 mlen--; 201 byte_swapped = 1; 202 } 203 /* 204 * Unroll the loop to make overhead from 205 * branches &c small. 206 */ 207 while ((mlen -= 32) >= 0) { 208 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 209 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 210 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 211 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 212 w += 16; 213 } 214 mlen += 32; 215 while ((mlen -= 8) >= 0) { 216 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 217 w += 4; 218 } 219 mlen += 8; 220 if (mlen == 0 && byte_swapped == 0) 221 goto next; 222 REDUCE; 223 while ((mlen -= 2) >= 0) { 224 sum += *w++; 225 } 226 if (byte_swapped) { 227 REDUCE; 228 sum <<= 8; 229 byte_swapped = 0; 230 if (mlen == -1) { 231 s_util.c[1] = *(char *)w; 232 sum += s_util.s; 233 mlen = 0; 234 } else 235 mlen = -1; 236 } else if (mlen == -1) 237 s_util.c[0] = *(char *)w; 238 next: 239 m = m->m_next; 240 241 /* 242 * Lastly calculate a summary of the rest of mbufs. 243 */ 244 245 for (;m && len; m = m->m_next) { 246 if (m->m_len == 0) 247 continue; 248 w = mtod(m, u_int16_t *); 249 if (mlen == -1) { 250 /* 251 * The first byte of this mbuf is the continuation 252 * of a word spanning between this mbuf and the 253 * last mbuf. 254 * 255 * s_util.c[0] is already saved when scanning previous 256 * mbuf. 257 */ 258 s_util.c[1] = *(char *)w; 259 sum += s_util.s; 260 w = (u_int16_t *)((char *)w + 1); 261 mlen = m->m_len - 1; 262 len--; 263 } else 264 mlen = m->m_len; 265 if (len < mlen) 266 mlen = len; 267 len -= mlen; 268 /* 269 * Force to even boundary. 270 */ 271 if ((1 & (long) w) && (mlen > 0)) { 272 REDUCE; 273 sum <<= 8; 274 s_util.c[0] = *(u_char *)w; 275 w = (u_int16_t *)((char *)w + 1); 276 mlen--; 277 byte_swapped = 1; 278 } 279 /* 280 * Unroll the loop to make overhead from 281 * branches &c small. 282 */ 283 while ((mlen -= 32) >= 0) { 284 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 285 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 286 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 287 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 288 w += 16; 289 } 290 mlen += 32; 291 while ((mlen -= 8) >= 0) { 292 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 293 w += 4; 294 } 295 mlen += 8; 296 if (mlen == 0 && byte_swapped == 0) 297 continue; 298 REDUCE; 299 while ((mlen -= 2) >= 0) { 300 sum += *w++; 301 } 302 if (byte_swapped) { 303 REDUCE; 304 sum <<= 8; 305 byte_swapped = 0; 306 if (mlen == -1) { 307 s_util.c[1] = *(char *)w; 308 sum += s_util.s; 309 mlen = 0; 310 } else 311 mlen = -1; 312 } else if (mlen == -1) 313 s_util.c[0] = *(char *)w; 314 } 315 if (len) 316 panic("in6_cksum: out of data\n"); 317 if (mlen == -1) { 318 /* The last mbuf has odd # of bytes. Follow the 319 standard (the odd byte may be shifted left by 8 bits 320 or not as determined by endian-ness of the machine) */ 321 s_util.c[1] = 0; 322 sum += s_util.s; 323 } 324 REDUCE; 325 return (~sum & 0xffff); 326 } 327
Indexes created Wed Oct 01 19:09:53 GMT 2025