in6_cksum.c revision 1.2
1 /* 2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the project nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 /* 31 * Copyright (c) 1988, 1992, 1993 32 * The Regents of the University of California. All rights reserved. 33 * 34 * Redistribution and use in source and binary forms, with or without 35 * modification, are permitted provided that the following conditions 36 * are met: 37 * 1. Redistributions of source code must retain the above copyright 38 * notice, this list of conditions and the following disclaimer. 39 * 2. Redistributions in binary form must reproduce the above copyright 40 * notice, this list of conditions and the following disclaimer in the 41 * documentation and/or other materials provided with the distribution. 42 * 3. All advertising materials mentioning features or use of this software 43 * must display the following acknowledgement: 44 * This product includes software developed by the University of 45 * California, Berkeley and its contributors. 46 * 4. 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 <netinet6/ip6.h> 70 71 /* 72 * Checksum routine for Internet Protocol family headers (Portable Version). 73 * 74 * This routine is very heavily used in the network 75 * code and should be modified for each CPU to be as fast as possible. 76 */ 77 78 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 79 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} 80 81 static union { 82 u_short phs[4]; 83 struct { 84 u_long ph_len; 85 u_char ph_zero[3]; 86 u_char ph_nxt; 87 } ph; 88 } uph; 89 90 /* 91 * m MUST contain a continuous IP6 header. 92 * off is a offset where TCP/UDP/ICMP6 header starts. 93 * len is a total length of a transport segment. 94 * (e.g. TCP header + TCP payload) 95 */ 96 97 int 98 in6_cksum(m, nxt, off, len) 99 register struct mbuf *m; 100 u_int8_t nxt; 101 register int off, len; 102 { 103 register u_short *w; 104 register int sum = 0; 105 register int mlen = 0; 106 int byte_swapped = 0; 107 #if 0 108 int srcifid = 0, dstifid = 0; 109 #endif 110 struct ip6_hdr *ip6; 111 112 union { 113 char c[2]; 114 u_short s; 115 } s_util; 116 union { 117 u_short s[2]; 118 long l; 119 } l_util; 120 121 /* sanity check */ 122 if (m->m_pkthdr.len < off + len) { 123 panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)\n", 124 m->m_pkthdr.len, off, len); 125 } 126 127 /* 128 * First create IP6 pseudo header and calculate a summary. 129 */ 130 ip6 = mtod(m, struct ip6_hdr *); 131 #if 0 132 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { 133 srcifid = ip6->ip6_src.s6_addr16[1]; 134 ip6->ip6_src.s6_addr16[1] = 0; 135 } 136 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { 137 dstifid = ip6->ip6_dst.s6_addr16[1]; 138 ip6->ip6_dst.s6_addr16[1] = 0; 139 } 140 #endif 141 w = (u_short *)&ip6->ip6_src; 142 uph.ph.ph_len = htonl(len); 143 uph.ph.ph_nxt = nxt; 144 145 /* IPv6 source address */ 146 sum += w[0]; 147 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 148 sum += w[1]; 149 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; 150 sum += w[6]; sum += w[7]; 151 /* IPv6 destination address */ 152 sum += w[8]; 153 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 154 sum += w[9]; 155 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; 156 sum += w[14]; sum += w[15]; 157 /* Payload length and upper layer identifier */ 158 sum += uph.phs[0]; sum += uph.phs[1]; 159 sum += uph.phs[2]; sum += uph.phs[3]; 160 161 #if 0 162 if (srcifid) 163 ip6->ip6_src.s6_addr16[1] = srcifid; 164 if (dstifid) 165 ip6->ip6_dst.s6_addr16[1] = dstifid; 166 #endif 167 /* 168 * Secondly calculate a summary of the first mbuf excluding offset. 169 */ 170 while (m != NULL && off > 0) { 171 if (m->m_len <= off) 172 off -= m->m_len; 173 else 174 break; 175 m = m->m_next; 176 } 177 w = (u_short *)(mtod(m, u_char *) + off); 178 mlen = m->m_len - off; 179 if (len < mlen) 180 mlen = len; 181 len -= mlen; 182 /* 183 * Force to even boundary. 184 */ 185 if ((1 & (int) w) && (mlen > 0)) { 186 REDUCE; 187 sum <<= 8; 188 s_util.c[0] = *(u_char *)w; 189 w = (u_short *)((char *)w + 1); 190 mlen--; 191 byte_swapped = 1; 192 } 193 /* 194 * Unroll the loop to make overhead from 195 * branches &c small. 196 */ 197 while ((mlen -= 32) >= 0) { 198 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 199 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 200 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 201 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 202 w += 16; 203 } 204 mlen += 32; 205 while ((mlen -= 8) >= 0) { 206 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 207 w += 4; 208 } 209 mlen += 8; 210 if (mlen == 0 && byte_swapped == 0) 211 goto next; 212 REDUCE; 213 while ((mlen -= 2) >= 0) { 214 sum += *w++; 215 } 216 if (byte_swapped) { 217 REDUCE; 218 sum <<= 8; 219 byte_swapped = 0; 220 if (mlen == -1) { 221 s_util.c[1] = *(char *)w; 222 sum += s_util.s; 223 mlen = 0; 224 } else 225 mlen = -1; 226 } else if (mlen == -1) 227 s_util.c[0] = *(char *)w; 228 next: 229 m = m->m_next; 230 231 /* 232 * Lastly calculate a summary of the rest of mbufs. 233 */ 234 235 for (;m && len; m = m->m_next) { 236 if (m->m_len == 0) 237 continue; 238 w = mtod(m, u_short *); 239 if (mlen == -1) { 240 /* 241 * The first byte of this mbuf is the continuation 242 * of a word spanning between this mbuf and the 243 * last mbuf. 244 * 245 * s_util.c[0] is already saved when scanning previous 246 * mbuf. 247 */ 248 s_util.c[1] = *(char *)w; 249 sum += s_util.s; 250 w = (u_short *)((char *)w + 1); 251 mlen = m->m_len - 1; 252 len--; 253 } else 254 mlen = m->m_len; 255 if (len < mlen) 256 mlen = len; 257 len -= mlen; 258 /* 259 * Force to even boundary. 260 */ 261 if ((1 & (int) w) && (mlen > 0)) { 262 REDUCE; 263 sum <<= 8; 264 s_util.c[0] = *(u_char *)w; 265 w = (u_short *)((char *)w + 1); 266 mlen--; 267 byte_swapped = 1; 268 } 269 /* 270 * Unroll the loop to make overhead from 271 * branches &c small. 272 */ 273 while ((mlen -= 32) >= 0) { 274 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 275 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 276 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 277 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 278 w += 16; 279 } 280 mlen += 32; 281 while ((mlen -= 8) >= 0) { 282 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 283 w += 4; 284 } 285 mlen += 8; 286 if (mlen == 0 && byte_swapped == 0) 287 continue; 288 REDUCE; 289 while ((mlen -= 2) >= 0) { 290 sum += *w++; 291 } 292 if (byte_swapped) { 293 REDUCE; 294 sum <<= 8; 295 byte_swapped = 0; 296 if (mlen == -1) { 297 s_util.c[1] = *(char *)w; 298 sum += s_util.s; 299 mlen = 0; 300 } else 301 mlen = -1; 302 } else if (mlen == -1) 303 s_util.c[0] = *(char *)w; 304 } 305 if (len) 306 panic("in6_cksum: out of data\n"); 307 if (mlen == -1) { 308 /* The last mbuf has odd # of bytes. Follow the 309 standard (the odd byte may be shifted left by 8 bits 310 or not as determined by endian-ness of the machine) */ 311 s_util.c[1] = 0; 312 sum += s_util.s; 313 } 314 REDUCE; 315 return (~sum & 0xffff); 316 } 317
Indexes created Wed Oct 01 15:09:59 GMT 2025