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 * $FreeBSD$ 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 #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 register int 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 struct ip6_hdr *ip6; 112 113 union { 114 u_int8_t c[2]; 115 u_int16_t s; 116 } s_util; 117 union { 118 u_int16_t s[2]; 119 u_int32_t l; 120 } l_util; 121 122 /* sanity check */ 123 if (m->m_pkthdr.len < off + len) { 124 panic("in6_cksum: mbuf len (%d) < off+len (%d+%d)\n", 125 m->m_pkthdr.len, off, len); 126 } 127 128 /* 129 * First create IP6 pseudo header and calculate a summary. 130 */ 131 ip6 = mtod(m, struct ip6_hdr *); 132 w = (u_int16_t *)&ip6->ip6_src; 133 uph.ph.ph_len = htonl(len); 134 uph.ph.ph_nxt = nxt; 135 136 /* IPv6 source address */ 137 sum += w[0]; 138 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 139 sum += w[1]; 140 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; 141 sum += w[6]; sum += w[7]; 142 /* IPv6 destination address */ 143 sum += w[8]; 144 if (!IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 145 sum += w[9]; 146 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; 147 sum += w[14]; sum += w[15]; 148 /* Payload length and upper layer identifier */ 149 sum += uph.phs[0]; sum += uph.phs[1]; 150 sum += uph.phs[2]; sum += uph.phs[3]; 151 152 /* 153 * Secondly calculate a summary of the first mbuf excluding offset. 154 */ 155 while (m != NULL && off > 0) { 156 if (m->m_len <= off) 157 off -= m->m_len; 158 else 159 break; 160 m = m->m_next; 161 } 162 w = (u_int16_t *)(mtod(m, u_char *) + off); 163 mlen = m->m_len - off; 164 if (len < mlen) 165 mlen = len; 166 len -= mlen; 167 /* 168 * Force to even boundary. 169 */ 170 if ((1 & (long) w) && (mlen > 0)) { 171 REDUCE; 172 sum <<= 8; 173 s_util.c[0] = *(u_char *)w; 174 w = (u_int16_t *)((char *)w + 1); 175 mlen--; 176 byte_swapped = 1; 177 } 178 /* 179 * Unroll the loop to make overhead from 180 * branches &c small. 181 */ 182 while ((mlen -= 32) >= 0) { 183 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 184 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 185 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 186 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 187 w += 16; 188 } 189 mlen += 32; 190 while ((mlen -= 8) >= 0) { 191 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 192 w += 4; 193 } 194 mlen += 8; 195 if (mlen == 0 && byte_swapped == 0) 196 goto next; 197 REDUCE; 198 while ((mlen -= 2) >= 0) { 199 sum += *w++; 200 } 201 if (byte_swapped) { 202 REDUCE; 203 sum <<= 8; 204 byte_swapped = 0; 205 if (mlen == -1) { 206 s_util.c[1] = *(char *)w; 207 sum += s_util.s; 208 mlen = 0; 209 } else 210 mlen = -1; 211 } else if (mlen == -1) 212 s_util.c[0] = *(char *)w; 213 next: 214 m = m->m_next; 215 216 /* 217 * Lastly calculate a summary of the rest of mbufs. 218 */ 219 220 for (;m && len; m = m->m_next) { 221 if (m->m_len == 0) 222 continue; 223 w = mtod(m, u_int16_t *); 224 if (mlen == -1) { 225 /* 226 * The first byte of this mbuf is the continuation 227 * of a word spanning between this mbuf and the 228 * last mbuf. 229 * 230 * s_util.c[0] is already saved when scanning previous 231 * mbuf. 232 */ 233 s_util.c[1] = *(char *)w; 234 sum += s_util.s; 235 w = (u_int16_t *)((char *)w + 1); 236 mlen = m->m_len - 1; 237 len--; 238 } else 239 mlen = m->m_len; 240 if (len < mlen) 241 mlen = len; 242 len -= mlen; 243 /* 244 * Force to even boundary. 245 */ 246 if ((1 & (long) w) && (mlen > 0)) { 247 REDUCE; 248 sum <<= 8; 249 s_util.c[0] = *(u_char *)w; 250 w = (u_int16_t *)((char *)w + 1); 251 mlen--; 252 byte_swapped = 1; 253 } 254 /* 255 * Unroll the loop to make overhead from 256 * branches &c small. 257 */ 258 while ((mlen -= 32) >= 0) { 259 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 260 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 261 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 262 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 263 w += 16; 264 } 265 mlen += 32; 266 while ((mlen -= 8) >= 0) { 267 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 268 w += 4; 269 } 270 mlen += 8; 271 if (mlen == 0 && byte_swapped == 0) 272 continue; 273 REDUCE; 274 while ((mlen -= 2) >= 0) { 275 sum += *w++; 276 } 277 if (byte_swapped) { 278 REDUCE; 279 sum <<= 8; 280 byte_swapped = 0; 281 if (mlen == -1) { 282 s_util.c[1] = *(char *)w; 283 sum += s_util.s; 284 mlen = 0; 285 } else 286 mlen = -1; 287 } else if (mlen == -1) 288 s_util.c[0] = *(char *)w; 289 } 290 if (len) 291 panic("in6_cksum: out of data\n"); 292 if (mlen == -1) { 293 /* The last mbuf has odd # of bytes. Follow the 294 standard (the odd byte may be shifted left by 8 bits 295 or not as determined by endian-ness of the machine) */ 296 s_util.c[1] = 0; 297 sum += s_util.s; 298 } 299 REDUCE; 300 return (~sum & 0xffff); 301 } 302