in6_cksum.c revision 1.2
1 1.2 itojun /* 2 1.2 itojun * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 3 1.2 itojun * All rights reserved. 4 1.2 itojun * 5 1.2 itojun * Redistribution and use in source and binary forms, with or without 6 1.2 itojun * modification, are permitted provided that the following conditions 7 1.2 itojun * are met: 8 1.2 itojun * 1. Redistributions of source code must retain the above copyright 9 1.2 itojun * notice, this list of conditions and the following disclaimer. 10 1.2 itojun * 2. Redistributions in binary form must reproduce the above copyright 11 1.2 itojun * notice, this list of conditions and the following disclaimer in the 12 1.2 itojun * documentation and/or other materials provided with the distribution. 13 1.2 itojun * 3. Neither the name of the project nor the names of its contributors 14 1.2 itojun * may be used to endorse or promote products derived from this software 15 1.2 itojun * without specific prior written permission. 16 1.2 itojun * 17 1.2 itojun * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 18 1.2 itojun * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 1.2 itojun * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 1.2 itojun * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 21 1.2 itojun * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 1.2 itojun * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 1.2 itojun * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 1.2 itojun * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 1.2 itojun * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 1.2 itojun * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 1.2 itojun * SUCH DAMAGE. 28 1.2 itojun */ 29 1.2 itojun 30 1.2 itojun /* 31 1.2 itojun * Copyright (c) 1988, 1992, 1993 32 1.2 itojun * The Regents of the University of California. All rights reserved. 33 1.2 itojun * 34 1.2 itojun * Redistribution and use in source and binary forms, with or without 35 1.2 itojun * modification, are permitted provided that the following conditions 36 1.2 itojun * are met: 37 1.2 itojun * 1. Redistributions of source code must retain the above copyright 38 1.2 itojun * notice, this list of conditions and the following disclaimer. 39 1.2 itojun * 2. Redistributions in binary form must reproduce the above copyright 40 1.2 itojun * notice, this list of conditions and the following disclaimer in the 41 1.2 itojun * documentation and/or other materials provided with the distribution. 42 1.2 itojun * 3. All advertising materials mentioning features or use of this software 43 1.2 itojun * must display the following acknowledgement: 44 1.2 itojun * This product includes software developed by the University of 45 1.2 itojun * California, Berkeley and its contributors. 46 1.2 itojun * 4. Neither the name of the University nor the names of its contributors 47 1.2 itojun * may be used to endorse or promote products derived from this software 48 1.2 itojun * without specific prior written permission. 49 1.2 itojun * 50 1.2 itojun * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 51 1.2 itojun * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 52 1.2 itojun * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 53 1.2 itojun * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 54 1.2 itojun * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 55 1.2 itojun * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 56 1.2 itojun * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 57 1.2 itojun * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 58 1.2 itojun * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 59 1.2 itojun * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 60 1.2 itojun * SUCH DAMAGE. 61 1.2 itojun * 62 1.2 itojun * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 63 1.2 itojun */ 64 1.2 itojun 65 1.2 itojun #include <sys/param.h> 66 1.2 itojun #include <sys/mbuf.h> 67 1.2 itojun #include <sys/systm.h> 68 1.2 itojun #include <netinet/in.h> 69 1.2 itojun #include <netinet6/ip6.h> 70 1.2 itojun 71 1.2 itojun /* 72 1.2 itojun * Checksum routine for Internet Protocol family headers (Portable Version). 73 1.2 itojun * 74 1.2 itojun * This routine is very heavily used in the network 75 1.2 itojun * code and should be modified for each CPU to be as fast as possible. 76 1.2 itojun */ 77 1.2 itojun 78 1.2 itojun #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 79 1.2 itojun #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} 80 1.2 itojun 81 1.2 itojun static union { 82 1.2 itojun u_short phs[4]; 83 1.2 itojun struct { 84 1.2 itojun u_long ph_len; 85 1.2 itojun u_char ph_zero[3]; 86 1.2 itojun u_char ph_nxt; 87 1.2 itojun } ph; 88 1.2 itojun } uph; 89 1.2 itojun 90 1.2 itojun /* 91 1.2 itojun * m MUST contain a continuous IP6 header. 92 1.2 itojun * off is a offset where TCP/UDP/ICMP6 header starts. 93 1.2 itojun * len is a total length of a transport segment. 94 1.2 itojun * (e.g. TCP header + TCP payload) 95 1.2 itojun */ 96 1.2 itojun 97 1.2 itojun int 98 1.2 itojun in6_cksum(m, nxt, off, len) 99 1.2 itojun register struct mbuf *m; 100 1.2 itojun u_int8_t nxt; 101 1.2 itojun register int off, len; 102 1.2 itojun { 103 1.2 itojun register u_short *w; 104 1.2 itojun register int sum = 0; 105 1.2 itojun register int mlen = 0; 106 1.2 itojun int byte_swapped = 0; 107 1.2 itojun #if 0 108 1.2 itojun int srcifid = 0, dstifid = 0; 109 1.2 itojun #endif 110 1.2 itojun struct ip6_hdr *ip6; 111 1.2 itojun 112 1.2 itojun union { 113 1.2 itojun char c[2]; 114 1.2 itojun u_short s; 115 1.2 itojun } s_util; 116 1.2 itojun union { 117 1.2 itojun u_short s[2]; 118 1.2 itojun long l; 119 1.2 itojun } l_util; 120 1.2 itojun 121 1.2 itojun /* sanity check */ 122 1.2 itojun if (m->m_pkthdr.len < off + len) { 123 1.2 itojun panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)\n", 124 1.2 itojun m->m_pkthdr.len, off, len); 125 1.2 itojun } 126 1.2 itojun 127 1.2 itojun /* 128 1.2 itojun * First create IP6 pseudo header and calculate a summary. 129 1.2 itojun */ 130 1.2 itojun ip6 = mtod(m, struct ip6_hdr *); 131 1.2 itojun #if 0 132 1.2 itojun if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { 133 1.2 itojun srcifid = ip6->ip6_src.s6_addr16[1]; 134 1.2 itojun ip6->ip6_src.s6_addr16[1] = 0; 135 1.2 itojun } 136 1.2 itojun if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { 137 1.2 itojun dstifid = ip6->ip6_dst.s6_addr16[1]; 138 1.2 itojun ip6->ip6_dst.s6_addr16[1] = 0; 139 1.2 itojun } 140 1.2 itojun #endif 141 1.2 itojun w = (u_short *)&ip6->ip6_src; 142 1.2 itojun uph.ph.ph_len = htonl(len); 143 1.2 itojun uph.ph.ph_nxt = nxt; 144 1.2 itojun 145 1.2 itojun /* IPv6 source address */ 146 1.2 itojun sum += w[0]; 147 1.2 itojun if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 148 1.2 itojun sum += w[1]; 149 1.2 itojun sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; 150 1.2 itojun sum += w[6]; sum += w[7]; 151 1.2 itojun /* IPv6 destination address */ 152 1.2 itojun sum += w[8]; 153 1.2 itojun if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 154 1.2 itojun sum += w[9]; 155 1.2 itojun sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; 156 1.2 itojun sum += w[14]; sum += w[15]; 157 1.2 itojun /* Payload length and upper layer identifier */ 158 1.2 itojun sum += uph.phs[0]; sum += uph.phs[1]; 159 1.2 itojun sum += uph.phs[2]; sum += uph.phs[3]; 160 1.2 itojun 161 1.2 itojun #if 0 162 1.2 itojun if (srcifid) 163 1.2 itojun ip6->ip6_src.s6_addr16[1] = srcifid; 164 1.2 itojun if (dstifid) 165 1.2 itojun ip6->ip6_dst.s6_addr16[1] = dstifid; 166 1.2 itojun #endif 167 1.2 itojun /* 168 1.2 itojun * Secondly calculate a summary of the first mbuf excluding offset. 169 1.2 itojun */ 170 1.2 itojun while (m != NULL && off > 0) { 171 1.2 itojun if (m->m_len <= off) 172 1.2 itojun off -= m->m_len; 173 1.2 itojun else 174 1.2 itojun break; 175 1.2 itojun m = m->m_next; 176 1.2 itojun } 177 1.2 itojun w = (u_short *)(mtod(m, u_char *) + off); 178 1.2 itojun mlen = m->m_len - off; 179 1.2 itojun if (len < mlen) 180 1.2 itojun mlen = len; 181 1.2 itojun len -= mlen; 182 1.2 itojun /* 183 1.2 itojun * Force to even boundary. 184 1.2 itojun */ 185 1.2 itojun if ((1 & (int) w) && (mlen > 0)) { 186 1.2 itojun REDUCE; 187 1.2 itojun sum <<= 8; 188 1.2 itojun s_util.c[0] = *(u_char *)w; 189 1.2 itojun w = (u_short *)((char *)w + 1); 190 1.2 itojun mlen--; 191 1.2 itojun byte_swapped = 1; 192 1.2 itojun } 193 1.2 itojun /* 194 1.2 itojun * Unroll the loop to make overhead from 195 1.2 itojun * branches &c small. 196 1.2 itojun */ 197 1.2 itojun while ((mlen -= 32) >= 0) { 198 1.2 itojun sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 199 1.2 itojun sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 200 1.2 itojun sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 201 1.2 itojun sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 202 1.2 itojun w += 16; 203 1.2 itojun } 204 1.2 itojun mlen += 32; 205 1.2 itojun while ((mlen -= 8) >= 0) { 206 1.2 itojun sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 207 1.2 itojun w += 4; 208 1.2 itojun } 209 1.2 itojun mlen += 8; 210 1.2 itojun if (mlen == 0 && byte_swapped == 0) 211 1.2 itojun goto next; 212 1.2 itojun REDUCE; 213 1.2 itojun while ((mlen -= 2) >= 0) { 214 1.2 itojun sum += *w++; 215 1.2 itojun } 216 1.2 itojun if (byte_swapped) { 217 1.2 itojun REDUCE; 218 1.2 itojun sum <<= 8; 219 1.2 itojun byte_swapped = 0; 220 1.2 itojun if (mlen == -1) { 221 1.2 itojun s_util.c[1] = *(char *)w; 222 1.2 itojun sum += s_util.s; 223 1.2 itojun mlen = 0; 224 1.2 itojun } else 225 1.2 itojun mlen = -1; 226 1.2 itojun } else if (mlen == -1) 227 1.2 itojun s_util.c[0] = *(char *)w; 228 1.2 itojun next: 229 1.2 itojun m = m->m_next; 230 1.2 itojun 231 1.2 itojun /* 232 1.2 itojun * Lastly calculate a summary of the rest of mbufs. 233 1.2 itojun */ 234 1.2 itojun 235 1.2 itojun for (;m && len; m = m->m_next) { 236 1.2 itojun if (m->m_len == 0) 237 1.2 itojun continue; 238 1.2 itojun w = mtod(m, u_short *); 239 1.2 itojun if (mlen == -1) { 240 1.2 itojun /* 241 1.2 itojun * The first byte of this mbuf is the continuation 242 1.2 itojun * of a word spanning between this mbuf and the 243 1.2 itojun * last mbuf. 244 1.2 itojun * 245 1.2 itojun * s_util.c[0] is already saved when scanning previous 246 1.2 itojun * mbuf. 247 1.2 itojun */ 248 1.2 itojun s_util.c[1] = *(char *)w; 249 1.2 itojun sum += s_util.s; 250 1.2 itojun w = (u_short *)((char *)w + 1); 251 1.2 itojun mlen = m->m_len - 1; 252 1.2 itojun len--; 253 1.2 itojun } else 254 1.2 itojun mlen = m->m_len; 255 1.2 itojun if (len < mlen) 256 1.2 itojun mlen = len; 257 1.2 itojun len -= mlen; 258 1.2 itojun /* 259 1.2 itojun * Force to even boundary. 260 1.2 itojun */ 261 1.2 itojun if ((1 & (int) w) && (mlen > 0)) { 262 1.2 itojun REDUCE; 263 1.2 itojun sum <<= 8; 264 1.2 itojun s_util.c[0] = *(u_char *)w; 265 1.2 itojun w = (u_short *)((char *)w + 1); 266 1.2 itojun mlen--; 267 1.2 itojun byte_swapped = 1; 268 1.2 itojun } 269 1.2 itojun /* 270 1.2 itojun * Unroll the loop to make overhead from 271 1.2 itojun * branches &c small. 272 1.2 itojun */ 273 1.2 itojun while ((mlen -= 32) >= 0) { 274 1.2 itojun sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 275 1.2 itojun sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 276 1.2 itojun sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 277 1.2 itojun sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 278 1.2 itojun w += 16; 279 1.2 itojun } 280 1.2 itojun mlen += 32; 281 1.2 itojun while ((mlen -= 8) >= 0) { 282 1.2 itojun sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 283 1.2 itojun w += 4; 284 1.2 itojun } 285 1.2 itojun mlen += 8; 286 1.2 itojun if (mlen == 0 && byte_swapped == 0) 287 1.2 itojun continue; 288 1.2 itojun REDUCE; 289 1.2 itojun while ((mlen -= 2) >= 0) { 290 1.2 itojun sum += *w++; 291 1.2 itojun } 292 1.2 itojun if (byte_swapped) { 293 1.2 itojun REDUCE; 294 1.2 itojun sum <<= 8; 295 1.2 itojun byte_swapped = 0; 296 1.2 itojun if (mlen == -1) { 297 1.2 itojun s_util.c[1] = *(char *)w; 298 1.2 itojun sum += s_util.s; 299 1.2 itojun mlen = 0; 300 1.2 itojun } else 301 1.2 itojun mlen = -1; 302 1.2 itojun } else if (mlen == -1) 303 1.2 itojun s_util.c[0] = *(char *)w; 304 1.2 itojun } 305 1.2 itojun if (len) 306 1.2 itojun panic("in6_cksum: out of data\n"); 307 1.2 itojun if (mlen == -1) { 308 1.2 itojun /* The last mbuf has odd # of bytes. Follow the 309 1.2 itojun standard (the odd byte may be shifted left by 8 bits 310 1.2 itojun or not as determined by endian-ness of the machine) */ 311 1.2 itojun s_util.c[1] = 0; 312 1.2 itojun sum += s_util.s; 313 1.2 itojun } 314 1.2 itojun REDUCE; 315 1.2 itojun return (~sum & 0xffff); 316 1.2 itojun } 317
Indexes created Wed Oct 01 13:09:50 GMT 2025