in6_cksum.c revision 1.7
1 /* $NetBSD: in6_cksum.c,v 1.7 2000/02/06 12:49:43 itojun Exp $ */ 2 3 /* 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * Copyright (c) 1988, 1992, 1993 34 * The Regents of the University of California. All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions 38 * are met: 39 * 1. Redistributions of source code must retain the above copyright 40 * notice, this list of conditions and the following disclaimer. 41 * 2. Redistributions in binary form must reproduce the above copyright 42 * notice, this list of conditions and the following disclaimer in the 43 * documentation and/or other materials provided with the distribution. 44 * 3. All advertising materials mentioning features or use of this software 45 * must display the following acknowledgement: 46 * This product includes software developed by the University of 47 * California, Berkeley and its contributors. 48 * 4. Neither the name of the University nor the names of its contributors 49 * may be used to endorse or promote products derived from this software 50 * without specific prior written permission. 51 * 52 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 53 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 54 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 55 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 56 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 57 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 58 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 59 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 60 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 61 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 62 * SUCH DAMAGE. 63 * 64 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 65 */ 66 67 #include <sys/param.h> 68 #include <sys/mbuf.h> 69 #include <sys/systm.h> 70 #include <netinet/in.h> 71 #include <netinet/ip6.h> 72 73 #include <net/net_osdep.h> 74 75 /* 76 * Checksum routine for Internet Protocol family headers (Portable Version). 77 * 78 * This routine is very heavily used in the network 79 * code and should be modified for each CPU to be as fast as possible. 80 */ 81 82 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 83 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} 84 85 static union { 86 u_int16_t phs[4]; 87 struct { 88 u_int32_t ph_len; 89 u_int8_t ph_zero[3]; 90 u_int8_t ph_nxt; 91 } ph; 92 } uph; 93 94 /* 95 * m MUST contain a continuous IP6 header. 96 * off is a offset where TCP/UDP/ICMP6 header starts. 97 * len is a total length of a transport segment. 98 * (e.g. TCP header + TCP payload) 99 */ 100 101 int 102 in6_cksum(m, nxt, off, len) 103 register struct mbuf *m; 104 u_int8_t nxt; 105 u_int32_t off, len; 106 { 107 register u_int16_t *w; 108 register int sum = 0; 109 register int mlen = 0; 110 int byte_swapped = 0; 111 #if 0 112 int srcifid = 0, dstifid = 0; 113 #endif 114 struct ip6_hdr *ip6; 115 116 union { 117 u_int8_t c[2]; 118 u_int16_t s; 119 } s_util; 120 union { 121 u_int16_t s[2]; 122 u_int32_t l; 123 } l_util; 124 125 /* sanity check */ 126 if (m->m_pkthdr.len < off + len) { 127 panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)\n", 128 m->m_pkthdr.len, off, len); 129 } 130 131 /* 132 * First create IP6 pseudo header and calculate a summary. 133 */ 134 ip6 = mtod(m, struct ip6_hdr *); 135 #if 0 136 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { 137 srcifid = ip6->ip6_src.s6_addr16[1]; 138 ip6->ip6_src.s6_addr16[1] = 0; 139 } 140 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { 141 dstifid = ip6->ip6_dst.s6_addr16[1]; 142 ip6->ip6_dst.s6_addr16[1] = 0; 143 } 144 #endif 145 w = (u_int16_t *)&ip6->ip6_src; 146 uph.ph.ph_len = htonl(len); 147 uph.ph.ph_nxt = nxt; 148 149 /* IPv6 source address */ 150 sum += w[0]; 151 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 152 sum += w[1]; 153 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; 154 sum += w[6]; sum += w[7]; 155 /* IPv6 destination address */ 156 sum += w[8]; 157 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 158 sum += w[9]; 159 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; 160 sum += w[14]; sum += w[15]; 161 /* Payload length and upper layer identifier */ 162 sum += uph.phs[0]; sum += uph.phs[1]; 163 sum += uph.phs[2]; sum += uph.phs[3]; 164 165 #if 0 166 if (srcifid) 167 ip6->ip6_src.s6_addr16[1] = srcifid; 168 if (dstifid) 169 ip6->ip6_dst.s6_addr16[1] = dstifid; 170 #endif 171 /* 172 * Secondly calculate a summary of the first mbuf excluding offset. 173 */ 174 while (m != NULL && off > 0) { 175 if (m->m_len <= off) 176 off -= m->m_len; 177 else 178 break; 179 m = m->m_next; 180 } 181 w = (u_int16_t *)(mtod(m, u_char *) + off); 182 mlen = m->m_len - off; 183 if (len < mlen) 184 mlen = len; 185 len -= mlen; 186 /* 187 * Force to even boundary. 188 */ 189 if ((1 & (long) w) && (mlen > 0)) { 190 REDUCE; 191 sum <<= 8; 192 s_util.c[0] = *(u_char *)w; 193 w = (u_int16_t *)((char *)w + 1); 194 mlen--; 195 byte_swapped = 1; 196 } 197 /* 198 * Unroll the loop to make overhead from 199 * branches &c small. 200 */ 201 while ((mlen -= 32) >= 0) { 202 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 203 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 204 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 205 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 206 w += 16; 207 } 208 mlen += 32; 209 while ((mlen -= 8) >= 0) { 210 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 211 w += 4; 212 } 213 mlen += 8; 214 if (mlen == 0 && byte_swapped == 0) 215 goto next; 216 REDUCE; 217 while ((mlen -= 2) >= 0) { 218 sum += *w++; 219 } 220 if (byte_swapped) { 221 REDUCE; 222 sum <<= 8; 223 byte_swapped = 0; 224 if (mlen == -1) { 225 s_util.c[1] = *(char *)w; 226 sum += s_util.s; 227 mlen = 0; 228 } else 229 mlen = -1; 230 } else if (mlen == -1) 231 s_util.c[0] = *(char *)w; 232 next: 233 m = m->m_next; 234 235 /* 236 * Lastly calculate a summary of the rest of mbufs. 237 */ 238 239 for (;m && len; m = m->m_next) { 240 if (m->m_len == 0) 241 continue; 242 w = mtod(m, u_int16_t *); 243 if (mlen == -1) { 244 /* 245 * The first byte of this mbuf is the continuation 246 * of a word spanning between this mbuf and the 247 * last mbuf. 248 * 249 * s_util.c[0] is already saved when scanning previous 250 * mbuf. 251 */ 252 s_util.c[1] = *(char *)w; 253 sum += s_util.s; 254 w = (u_int16_t *)((char *)w + 1); 255 mlen = m->m_len - 1; 256 len--; 257 } else 258 mlen = m->m_len; 259 if (len < mlen) 260 mlen = len; 261 len -= mlen; 262 /* 263 * Force to even boundary. 264 */ 265 if ((1 & (long) w) && (mlen > 0)) { 266 REDUCE; 267 sum <<= 8; 268 s_util.c[0] = *(u_char *)w; 269 w = (u_int16_t *)((char *)w + 1); 270 mlen--; 271 byte_swapped = 1; 272 } 273 /* 274 * Unroll the loop to make overhead from 275 * branches &c small. 276 */ 277 while ((mlen -= 32) >= 0) { 278 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 279 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 280 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 281 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 282 w += 16; 283 } 284 mlen += 32; 285 while ((mlen -= 8) >= 0) { 286 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 287 w += 4; 288 } 289 mlen += 8; 290 if (mlen == 0 && byte_swapped == 0) 291 continue; 292 REDUCE; 293 while ((mlen -= 2) >= 0) { 294 sum += *w++; 295 } 296 if (byte_swapped) { 297 REDUCE; 298 sum <<= 8; 299 byte_swapped = 0; 300 if (mlen == -1) { 301 s_util.c[1] = *(char *)w; 302 sum += s_util.s; 303 mlen = 0; 304 } else 305 mlen = -1; 306 } else if (mlen == -1) 307 s_util.c[0] = *(char *)w; 308 } 309 if (len) 310 panic("in6_cksum: out of data\n"); 311 if (mlen == -1) { 312 /* The last mbuf has odd # of bytes. Follow the 313 standard (the odd byte may be shifted left by 8 bits 314 or not as determined by endian-ness of the machine) */ 315 s_util.c[1] = 0; 316 sum += s_util.s; 317 } 318 REDUCE; 319 return (~sum & 0xffff); 320 } 321
Indexes created Wed Oct 01 15:09:59 GMT 2025