in6_cksum.c revision 1.14
1 /* $NetBSD: in6_cksum.c,v 1.14 2002/09/27 15:37:53 provos 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/cdefs.h> 69 __KERNEL_RCSID(0, "$NetBSD: in6_cksum.c,v 1.14 2002/09/27 15:37:53 provos Exp $"); 70 71 #include <sys/param.h> 72 #include <sys/mbuf.h> 73 #include <sys/systm.h> 74 #include <netinet/in.h> 75 #include <netinet/ip6.h> 76 77 #include <net/net_osdep.h> 78 79 /* 80 * Checksum routine for Internet Protocol family headers (Portable Version). 81 * 82 * This routine is very heavily used in the network 83 * code and should be modified for each CPU to be as fast as possible. 84 */ 85 86 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 87 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} 88 89 /* 90 * m MUST contain a continuous IP6 header. 91 * off is a offset where TCP/UDP/ICMP6 header starts. 92 * len is a total length of a transport segment. 93 * (e.g. TCP header + TCP payload) 94 */ 95 96 int 97 in6_cksum(m, nxt, off, len) 98 struct mbuf *m; 99 u_int8_t nxt; 100 u_int32_t off, len; 101 { 102 u_int16_t *w; 103 int sum = 0; 104 int mlen = 0; 105 int byte_swapped = 0; 106 #if 0 107 int srcifid = 0, dstifid = 0; 108 #endif 109 struct ip6_hdr *ip6; 110 union { 111 u_int16_t phs[4]; 112 struct { 113 u_int32_t ph_len; 114 u_int8_t ph_zero[3]; 115 u_int8_t ph_nxt; 116 } ph __attribute__((__packed__)); 117 } uph; 118 union { 119 u_int8_t c[2]; 120 u_int16_t s; 121 } s_util; 122 union { 123 u_int16_t s[2]; 124 u_int32_t l; 125 } l_util; 126 127 /* sanity check */ 128 if (m->m_pkthdr.len < off + len) { 129 panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)", 130 m->m_pkthdr.len, off, len); 131 } 132 133 /* Skip pseudo-header if nxt == 0. */ 134 if (nxt == 0) 135 goto skip_phdr; 136 137 bzero(&uph, sizeof(uph)); 138 139 /* 140 * First create IP6 pseudo header and calculate a summary. 141 */ 142 ip6 = mtod(m, struct ip6_hdr *); 143 #if 0 144 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { 145 srcifid = ip6->ip6_src.s6_addr16[1]; 146 ip6->ip6_src.s6_addr16[1] = 0; 147 } 148 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { 149 dstifid = ip6->ip6_dst.s6_addr16[1]; 150 ip6->ip6_dst.s6_addr16[1] = 0; 151 } 152 #endif 153 w = (u_int16_t *)&ip6->ip6_src; 154 uph.ph.ph_len = htonl(len); 155 uph.ph.ph_nxt = nxt; 156 157 /* IPv6 source address */ 158 sum += w[0]; 159 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 160 sum += w[1]; 161 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; 162 sum += w[6]; sum += w[7]; 163 /* IPv6 destination address */ 164 sum += w[8]; 165 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 166 sum += w[9]; 167 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; 168 sum += w[14]; sum += w[15]; 169 /* Payload length and upper layer identifier */ 170 sum += uph.phs[0]; sum += uph.phs[1]; 171 sum += uph.phs[2]; sum += uph.phs[3]; 172 173 #if 0 174 if (srcifid) 175 ip6->ip6_src.s6_addr16[1] = srcifid; 176 if (dstifid) 177 ip6->ip6_dst.s6_addr16[1] = dstifid; 178 #endif 179 skip_phdr: 180 /* 181 * Secondly calculate a summary of the first mbuf excluding offset. 182 */ 183 while (m != NULL && off > 0) { 184 if (m->m_len <= off) 185 off -= m->m_len; 186 else 187 break; 188 m = m->m_next; 189 } 190 w = (u_int16_t *)(mtod(m, u_char *) + off); 191 mlen = m->m_len - off; 192 if (len < mlen) 193 mlen = len; 194 len -= mlen; 195 /* 196 * Force to even boundary. 197 */ 198 if ((1 & (long) w) && (mlen > 0)) { 199 REDUCE; 200 sum <<= 8; 201 s_util.c[0] = *(u_char *)w; 202 w = (u_int16_t *)((char *)w + 1); 203 mlen--; 204 byte_swapped = 1; 205 } 206 /* 207 * Unroll the loop to make overhead from 208 * branches &c small. 209 */ 210 while ((mlen -= 32) >= 0) { 211 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 212 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 213 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 214 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 215 w += 16; 216 } 217 mlen += 32; 218 while ((mlen -= 8) >= 0) { 219 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 220 w += 4; 221 } 222 mlen += 8; 223 if (mlen == 0 && byte_swapped == 0) 224 goto next; 225 REDUCE; 226 while ((mlen -= 2) >= 0) { 227 sum += *w++; 228 } 229 if (byte_swapped) { 230 REDUCE; 231 sum <<= 8; 232 byte_swapped = 0; 233 if (mlen == -1) { 234 s_util.c[1] = *(char *)w; 235 sum += s_util.s; 236 mlen = 0; 237 } else 238 mlen = -1; 239 } else if (mlen == -1) 240 s_util.c[0] = *(char *)w; 241 next: 242 m = m->m_next; 243 244 /* 245 * Lastly calculate a summary of the rest of mbufs. 246 */ 247 248 for (;m && len; m = m->m_next) { 249 if (m->m_len == 0) 250 continue; 251 w = mtod(m, u_int16_t *); 252 if (mlen == -1) { 253 /* 254 * The first byte of this mbuf is the continuation 255 * of a word spanning between this mbuf and the 256 * last mbuf. 257 * 258 * s_util.c[0] is already saved when scanning previous 259 * mbuf. 260 */ 261 s_util.c[1] = *(char *)w; 262 sum += s_util.s; 263 w = (u_int16_t *)((char *)w + 1); 264 mlen = m->m_len - 1; 265 len--; 266 } else 267 mlen = m->m_len; 268 if (len < mlen) 269 mlen = len; 270 len -= mlen; 271 /* 272 * Force to even boundary. 273 */ 274 if ((1 & (long) w) && (mlen > 0)) { 275 REDUCE; 276 sum <<= 8; 277 s_util.c[0] = *(u_char *)w; 278 w = (u_int16_t *)((char *)w + 1); 279 mlen--; 280 byte_swapped = 1; 281 } 282 /* 283 * Unroll the loop to make overhead from 284 * branches &c small. 285 */ 286 while ((mlen -= 32) >= 0) { 287 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 288 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 289 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 290 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 291 w += 16; 292 } 293 mlen += 32; 294 while ((mlen -= 8) >= 0) { 295 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 296 w += 4; 297 } 298 mlen += 8; 299 if (mlen == 0 && byte_swapped == 0) 300 continue; 301 REDUCE; 302 while ((mlen -= 2) >= 0) { 303 sum += *w++; 304 } 305 if (byte_swapped) { 306 REDUCE; 307 sum <<= 8; 308 byte_swapped = 0; 309 if (mlen == -1) { 310 s_util.c[1] = *(char *)w; 311 sum += s_util.s; 312 mlen = 0; 313 } else 314 mlen = -1; 315 } else if (mlen == -1) 316 s_util.c[0] = *(char *)w; 317 } 318 if (len) 319 panic("in6_cksum: out of data"); 320 if (mlen == -1) { 321 /* The last mbuf has odd # of bytes. Follow the 322 standard (the odd byte may be shifted left by 8 bits 323 or not as determined by endian-ness of the machine) */ 324 s_util.c[1] = 0; 325 sum += s_util.s; 326 } 327 REDUCE; 328 return (~sum & 0xffff); 329 } 330
Indexes created Thu Oct 02 07:10:07 GMT 2025