1 /* $NetBSD: in6_cksum.c,v 1.19 2006/01/27 20:08:11 rpaulo Exp $ */ 2 /* $KAME: in6_cksum.c,v 1.9 2000/09/09 15:33:31 itojun Exp $ */ 3 4 /* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 /* 34 * Copyright (c) 1988, 1992, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 1. Redistributions of source code must retain the above copyright 41 * notice, this list of conditions and the following disclaimer. 42 * 2. Redistributions in binary form must reproduce the above copyright 43 * notice, this list of conditions and the following disclaimer in the 44 * documentation and/or other materials provided with the distribution. 45 * 3. Neither the name of the University nor the names of its contributors 46 * may be used to endorse or promote products derived from this software 47 * without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59 * SUCH DAMAGE. 60 * 61 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 62 */ 63 64 #include <sys/cdefs.h> 65 __KERNEL_RCSID(0, "$NetBSD: in6_cksum.c,v 1.19 2006/01/27 20:08:11 rpaulo Exp $"); 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 #include <netinet6/scope6_var.h> 73 74 #include <net/net_osdep.h> 75 76 /* 77 * Checksum routine for Internet Protocol family headers (Portable Version). 78 * 79 * This routine is very heavily used in the network 80 * code and should be modified for each CPU to be as fast as possible. 81 */ 82 83 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 84 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} 85 86 /* 87 * m MUST contain a continuous IP6 header. 88 * off is a offset where TCP/UDP/ICMP6 header starts. 89 * len is a total length of a transport segment. 90 * (e.g. TCP header + TCP payload) 91 */ 92 93 int 94 in6_cksum(m, nxt, off, len) 95 struct mbuf *m; 96 u_int8_t nxt; 97 u_int32_t off, len; 98 { 99 u_int16_t *w; 100 int sum = 0; 101 int mlen = 0; 102 int byte_swapped = 0; 103 struct ip6_hdr *ip6; 104 struct in6_addr in6; 105 union { 106 u_int16_t phs[4]; 107 struct { 108 u_int32_t ph_len; 109 u_int8_t ph_zero[3]; 110 u_int8_t ph_nxt; 111 } ph __attribute__((__packed__)); 112 } uph; 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)", 125 m->m_pkthdr.len, off, len); 126 } 127 128 /* Skip pseudo-header if nxt == 0. */ 129 if (nxt == 0) 130 goto skip_phdr; 131 132 bzero(&uph, sizeof(uph)); 133 134 /* 135 * First create IP6 pseudo header and calculate a summary. 136 */ 137 ip6 = mtod(m, struct ip6_hdr *); 138 w = (u_int16_t *)&ip6->ip6_src; 139 uph.ph.ph_len = htonl(len); 140 uph.ph.ph_nxt = nxt; 141 142 /* 143 * IPv6 source address 144 * XXX: we'd like to avoid copying the address, but we can't due to 145 * the possibly embedded scope zone ID. 146 */ 147 in6 = ip6->ip6_src; 148 in6_clearscope(&in6); 149 w = (u_int16_t *)&in6; 150 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 151 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 152 153 /* IPv6 destination address */ 154 in6 = ip6->ip6_dst; 155 in6_clearscope(&in6); 156 w = (u_int16_t *)&in6; 157 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 158 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 159 160 /* Payload length and upper layer identifier */ 161 sum += uph.phs[0]; sum += uph.phs[1]; 162 sum += uph.phs[2]; sum += uph.phs[3]; 163 164 skip_phdr: 165 /* 166 * Secondly calculate a summary of the first mbuf excluding offset. 167 */ 168 while (m != NULL && off > 0) { 169 if (m->m_len <= off) 170 off -= m->m_len; 171 else 172 break; 173 m = m->m_next; 174 } 175 w = (u_int16_t *)(mtod(m, u_char *) + off); 176 mlen = m->m_len - off; 177 if (len < mlen) 178 mlen = len; 179 len -= mlen; 180 /* 181 * Force to even boundary. 182 */ 183 if ((1 & (long) w) && (mlen > 0)) { 184 REDUCE; 185 sum <<= 8; 186 s_util.c[0] = *(u_char *)w; 187 w = (u_int16_t *)((char *)w + 1); 188 mlen--; 189 byte_swapped = 1; 190 } 191 /* 192 * Unroll the loop to make overhead from 193 * branches &c small. 194 */ 195 while ((mlen -= 32) >= 0) { 196 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 197 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 198 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 199 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 200 w += 16; 201 } 202 mlen += 32; 203 while ((mlen -= 8) >= 0) { 204 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 205 w += 4; 206 } 207 mlen += 8; 208 if (mlen == 0 && byte_swapped == 0) 209 goto next; 210 REDUCE; 211 while ((mlen -= 2) >= 0) { 212 sum += *w++; 213 } 214 if (byte_swapped) { 215 REDUCE; 216 sum <<= 8; 217 byte_swapped = 0; 218 if (mlen == -1) { 219 s_util.c[1] = *(char *)w; 220 sum += s_util.s; 221 mlen = 0; 222 } else 223 mlen = -1; 224 } else if (mlen == -1) 225 s_util.c[0] = *(char *)w; 226 next: 227 m = m->m_next; 228 229 /* 230 * Lastly calculate a summary of the rest of mbufs. 231 */ 232 233 for (;m && len; m = m->m_next) { 234 if (m->m_len == 0) 235 continue; 236 w = mtod(m, u_int16_t *); 237 if (mlen == -1) { 238 /* 239 * The first byte of this mbuf is the continuation 240 * of a word spanning between this mbuf and the 241 * last mbuf. 242 * 243 * s_util.c[0] is already saved when scanning previous 244 * mbuf. 245 */ 246 s_util.c[1] = *(char *)w; 247 sum += s_util.s; 248 w = (u_int16_t *)((char *)w + 1); 249 mlen = m->m_len - 1; 250 len--; 251 } else 252 mlen = m->m_len; 253 if (len < mlen) 254 mlen = len; 255 len -= mlen; 256 /* 257 * Force to even boundary. 258 */ 259 if ((1 & (long) w) && (mlen > 0)) { 260 REDUCE; 261 sum <<= 8; 262 s_util.c[0] = *(u_char *)w; 263 w = (u_int16_t *)((char *)w + 1); 264 mlen--; 265 byte_swapped = 1; 266 } 267 /* 268 * Unroll the loop to make overhead from 269 * branches &c small. 270 */ 271 while ((mlen -= 32) >= 0) { 272 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 273 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 274 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 275 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 276 w += 16; 277 } 278 mlen += 32; 279 while ((mlen -= 8) >= 0) { 280 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 281 w += 4; 282 } 283 mlen += 8; 284 if (mlen == 0 && byte_swapped == 0) 285 continue; 286 REDUCE; 287 while ((mlen -= 2) >= 0) { 288 sum += *w++; 289 } 290 if (byte_swapped) { 291 REDUCE; 292 sum <<= 8; 293 byte_swapped = 0; 294 if (mlen == -1) { 295 s_util.c[1] = *(char *)w; 296 sum += s_util.s; 297 mlen = 0; 298 } else 299 mlen = -1; 300 } else if (mlen == -1) 301 s_util.c[0] = *(char *)w; 302 } 303 if (len) 304 panic("in6_cksum: out of data"); 305 if (mlen == -1) { 306 /* The last mbuf has odd # of bytes. Follow the 307 standard (the odd byte may be shifted left by 8 bits 308 or not as determined by endian-ness of the machine) */ 309 s_util.c[1] = 0; 310 sum += s_util.s; 311 } 312 REDUCE; 313 return (~sum & 0xffff); 314 } 315