in6_cksum.c revision 1.3
1 /* $NetBSD: in6_cksum.c,v 1.3 1999/07/03 21:30:18 thorpej 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 <netinet6/ip6.h> 72 73 /* 74 * Checksum routine for Internet Protocol family headers (Portable Version). 75 * 76 * This routine is very heavily used in the network 77 * code and should be modified for each CPU to be as fast as possible. 78 */ 79 80 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 81 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} 82 83 static union { 84 u_short phs[4]; 85 struct { 86 u_long ph_len; 87 u_char ph_zero[3]; 88 u_char ph_nxt; 89 } ph; 90 } uph; 91 92 /* 93 * m MUST contain a continuous IP6 header. 94 * off is a offset where TCP/UDP/ICMP6 header starts. 95 * len is a total length of a transport segment. 96 * (e.g. TCP header + TCP payload) 97 */ 98 99 int 100 in6_cksum(m, nxt, off, len) 101 register struct mbuf *m; 102 u_int8_t nxt; 103 register int off, len; 104 { 105 register u_short *w; 106 register int sum = 0; 107 register int mlen = 0; 108 int byte_swapped = 0; 109 #if 0 110 int srcifid = 0, dstifid = 0; 111 #endif 112 struct ip6_hdr *ip6; 113 114 union { 115 char c[2]; 116 u_short s; 117 } s_util; 118 union { 119 u_short s[2]; 120 long l; 121 } l_util; 122 123 /* sanity check */ 124 if (m->m_pkthdr.len < off + len) { 125 panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)\n", 126 m->m_pkthdr.len, off, len); 127 } 128 129 /* 130 * First create IP6 pseudo header and calculate a summary. 131 */ 132 ip6 = mtod(m, struct ip6_hdr *); 133 #if 0 134 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { 135 srcifid = ip6->ip6_src.s6_addr16[1]; 136 ip6->ip6_src.s6_addr16[1] = 0; 137 } 138 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { 139 dstifid = ip6->ip6_dst.s6_addr16[1]; 140 ip6->ip6_dst.s6_addr16[1] = 0; 141 } 142 #endif 143 w = (u_short *)&ip6->ip6_src; 144 uph.ph.ph_len = htonl(len); 145 uph.ph.ph_nxt = nxt; 146 147 /* IPv6 source address */ 148 sum += w[0]; 149 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 150 sum += w[1]; 151 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; 152 sum += w[6]; sum += w[7]; 153 /* IPv6 destination address */ 154 sum += w[8]; 155 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 156 sum += w[9]; 157 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; 158 sum += w[14]; sum += w[15]; 159 /* Payload length and upper layer identifier */ 160 sum += uph.phs[0]; sum += uph.phs[1]; 161 sum += uph.phs[2]; sum += uph.phs[3]; 162 163 #if 0 164 if (srcifid) 165 ip6->ip6_src.s6_addr16[1] = srcifid; 166 if (dstifid) 167 ip6->ip6_dst.s6_addr16[1] = dstifid; 168 #endif 169 /* 170 * Secondly calculate a summary of the first mbuf excluding offset. 171 */ 172 while (m != NULL && off > 0) { 173 if (m->m_len <= off) 174 off -= m->m_len; 175 else 176 break; 177 m = m->m_next; 178 } 179 w = (u_short *)(mtod(m, u_char *) + off); 180 mlen = m->m_len - off; 181 if (len < mlen) 182 mlen = len; 183 len -= mlen; 184 /* 185 * Force to even boundary. 186 */ 187 if ((1 & (int) w) && (mlen > 0)) { 188 REDUCE; 189 sum <<= 8; 190 s_util.c[0] = *(u_char *)w; 191 w = (u_short *)((char *)w + 1); 192 mlen--; 193 byte_swapped = 1; 194 } 195 /* 196 * Unroll the loop to make overhead from 197 * branches &c small. 198 */ 199 while ((mlen -= 32) >= 0) { 200 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 201 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 202 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 203 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 204 w += 16; 205 } 206 mlen += 32; 207 while ((mlen -= 8) >= 0) { 208 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 209 w += 4; 210 } 211 mlen += 8; 212 if (mlen == 0 && byte_swapped == 0) 213 goto next; 214 REDUCE; 215 while ((mlen -= 2) >= 0) { 216 sum += *w++; 217 } 218 if (byte_swapped) { 219 REDUCE; 220 sum <<= 8; 221 byte_swapped = 0; 222 if (mlen == -1) { 223 s_util.c[1] = *(char *)w; 224 sum += s_util.s; 225 mlen = 0; 226 } else 227 mlen = -1; 228 } else if (mlen == -1) 229 s_util.c[0] = *(char *)w; 230 next: 231 m = m->m_next; 232 233 /* 234 * Lastly calculate a summary of the rest of mbufs. 235 */ 236 237 for (;m && len; m = m->m_next) { 238 if (m->m_len == 0) 239 continue; 240 w = mtod(m, u_short *); 241 if (mlen == -1) { 242 /* 243 * The first byte of this mbuf is the continuation 244 * of a word spanning between this mbuf and the 245 * last mbuf. 246 * 247 * s_util.c[0] is already saved when scanning previous 248 * mbuf. 249 */ 250 s_util.c[1] = *(char *)w; 251 sum += s_util.s; 252 w = (u_short *)((char *)w + 1); 253 mlen = m->m_len - 1; 254 len--; 255 } else 256 mlen = m->m_len; 257 if (len < mlen) 258 mlen = len; 259 len -= mlen; 260 /* 261 * Force to even boundary. 262 */ 263 if ((1 & (int) w) && (mlen > 0)) { 264 REDUCE; 265 sum <<= 8; 266 s_util.c[0] = *(u_char *)w; 267 w = (u_short *)((char *)w + 1); 268 mlen--; 269 byte_swapped = 1; 270 } 271 /* 272 * Unroll the loop to make overhead from 273 * branches &c small. 274 */ 275 while ((mlen -= 32) >= 0) { 276 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 277 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 278 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 279 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 280 w += 16; 281 } 282 mlen += 32; 283 while ((mlen -= 8) >= 0) { 284 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 285 w += 4; 286 } 287 mlen += 8; 288 if (mlen == 0 && byte_swapped == 0) 289 continue; 290 REDUCE; 291 while ((mlen -= 2) >= 0) { 292 sum += *w++; 293 } 294 if (byte_swapped) { 295 REDUCE; 296 sum <<= 8; 297 byte_swapped = 0; 298 if (mlen == -1) { 299 s_util.c[1] = *(char *)w; 300 sum += s_util.s; 301 mlen = 0; 302 } else 303 mlen = -1; 304 } else if (mlen == -1) 305 s_util.c[0] = *(char *)w; 306 } 307 if (len) 308 panic("in6_cksum: out of data\n"); 309 if (mlen == -1) { 310 /* The last mbuf has odd # of bytes. Follow the 311 standard (the odd byte may be shifted left by 8 bits 312 or not as determined by endian-ness of the machine) */ 313 s_util.c[1] = 0; 314 sum += s_util.s; 315 } 316 REDUCE; 317 return (~sum & 0xffff); 318 } 319
Indexes created Wed Oct 01 15:09:59 GMT 2025