1/* $OpenBSD: in6_cksum.c,v 1.18 2019/04/22 22:47:49 bluhm Exp $ */ 2/* $KAME: in6_cksum.c,v 1.10 2000/12/03 00:53:59 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/param.h> 65#include <sys/mbuf.h> 66#include <sys/systm.h> 67#include <netinet/in.h> 68#include <netinet/ip6.h> 69 70/* 71 * Checksum routine for Internet Protocol family headers (Portable Version). 72 * 73 * This routine is very heavily used in the network 74 * code and should be modified for each CPU to be as fast as possible. 75 */ 76 77#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) 78#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} 79 80/* 81 * m MUST contain a continuous IP6 header. 82 * off is a offset where TCP/UDP/ICMP6 header starts. 83 * len is a total length of a transport segment. 84 * (e.g. TCP header + TCP payload) 85 */ 86 87int 88in6_cksum(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len) 89{ 90 uint16_t *w; 91 int sum = 0; 92 int mlen = 0; 93 int byte_swapped = 0; 94 struct ip6_hdr *ip6; 95 union { 96 uint16_t phs[4]; 97 struct { 98 uint32_t ph_len; 99 uint8_t ph_zero[3]; 100 uint8_t ph_nxt; 101 } ph __packed; 102 } uph; 103 union { 104 uint8_t c[2]; 105 uint16_t s; 106 } s_util; 107 union { 108 uint16_t s[2]; 109 uint32_t l; 110 } l_util; 111 112 /* sanity check */ 113 if (m->m_pkthdr.len < off + len) { 114 panic("%s: mbuf len (%d) < off+len (%d+%d)", 115 __func__, m->m_pkthdr.len, off, len); 116 } 117 118 /* Skip pseudo-header if nxt == 0. */ 119 if (nxt == 0) 120 goto skip_phdr; 121 122 bzero(&uph, sizeof(uph)); 123 124 /* 125 * First create IP6 pseudo header and calculate a summary. 126 */ 127 ip6 = mtod(m, struct ip6_hdr *); 128 w = (uint16_t *)&ip6->ip6_src; 129 uph.ph.ph_len = htonl(len); 130 uph.ph.ph_nxt = nxt; 131 132 /* IPv6 source address */ 133 sum += w[0]; 134 if (!IN6_IS_SCOPE_EMBED(&ip6->ip6_src)) 135 sum += w[1]; 136 sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; 137 sum += w[6]; sum += w[7]; 138 /* IPv6 destination address */ 139 sum += w[8]; 140 if (!IN6_IS_SCOPE_EMBED(&ip6->ip6_dst)) 141 sum += w[9]; 142 sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; 143 sum += w[14]; sum += w[15]; 144 /* Payload length and upper layer identifier */ 145 sum += uph.phs[0]; sum += uph.phs[1]; 146 sum += uph.phs[2]; sum += uph.phs[3]; 147 148skip_phdr: 149 /* 150 * Secondly calculate a summary of the first mbuf excluding offset. 151 */ 152 while (m != NULL && off > 0) { 153 if (m->m_len <= off) 154 off -= m->m_len; 155 else 156 break; 157 m = m->m_next; 158 } 159 if (m == NULL) { 160 if (off) 161 panic("%s: out of header, off %u", __func__, off); 162 goto end; 163 } 164 w = (uint16_t *)(mtod(m, uint8_t *) + off); 165 mlen = m->m_len - off; 166 if (len < mlen) 167 mlen = len; 168 len -= mlen; 169 /* 170 * Force to even boundary. 171 */ 172 if ((1 & (long) w) && (mlen > 0)) { 173 REDUCE; 174 sum <<= 8; 175 s_util.c[0] = *(uint8_t *)w; 176 w = (uint16_t *)((uint8_t *)w + 1); 177 mlen--; 178 byte_swapped = 1; 179 } 180 /* 181 * Unroll the loop to make overhead from 182 * branches &c small. 183 */ 184 while ((mlen -= 32) >= 0) { 185 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 186 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 187 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 188 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 189 w += 16; 190 } 191 mlen += 32; 192 while ((mlen -= 8) >= 0) { 193 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 194 w += 4; 195 } 196 mlen += 8; 197 if (mlen == 0 && byte_swapped == 0) 198 goto next; 199 REDUCE; 200 while ((mlen -= 2) >= 0) { 201 sum += *w++; 202 } 203 if (byte_swapped) { 204 REDUCE; 205 sum <<= 8; 206 byte_swapped = 0; 207 if (mlen == -1) { 208 s_util.c[1] = *(uint8_t *)w; 209 sum += s_util.s; 210 mlen = 0; 211 } else 212 mlen = -1; 213 } else if (mlen == -1) 214 s_util.c[0] = *(uint8_t *)w; 215 next: 216 m = m->m_next; 217 218 /* 219 * Lastly calculate a summary of the rest of mbufs. 220 */ 221 222 for (;m && len; m = m->m_next) { 223 if (m->m_len == 0) 224 continue; 225 w = mtod(m, uint16_t *); 226 if (mlen == -1) { 227 /* 228 * The first byte of this mbuf is the continuation 229 * of a word spanning between this mbuf and the 230 * last mbuf. 231 * 232 * s_util.c[0] is already saved when scanning previous 233 * mbuf. 234 */ 235 s_util.c[1] = *(uint8_t *)w; 236 sum += s_util.s; 237 w = (uint16_t *)((uint8_t *)w + 1); 238 mlen = m->m_len - 1; 239 len--; 240 } else 241 mlen = m->m_len; 242 if (len < mlen) 243 mlen = len; 244 len -= mlen; 245 /* 246 * Force to even boundary. 247 */ 248 if ((1 & (long) w) && (mlen > 0)) { 249 REDUCE; 250 sum <<= 8; 251 s_util.c[0] = *(uint8_t *)w; 252 w = (uint16_t *)((uint8_t *)w + 1); 253 mlen--; 254 byte_swapped = 1; 255 } 256 /* 257 * Unroll the loop to make overhead from 258 * branches &c small. 259 */ 260 while ((mlen -= 32) >= 0) { 261 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 262 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 263 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 264 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 265 w += 16; 266 } 267 mlen += 32; 268 while ((mlen -= 8) >= 0) { 269 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 270 w += 4; 271 } 272 mlen += 8; 273 if (mlen == 0 && byte_swapped == 0) 274 continue; 275 REDUCE; 276 while ((mlen -= 2) >= 0) { 277 sum += *w++; 278 } 279 if (byte_swapped) { 280 REDUCE; 281 sum <<= 8; 282 byte_swapped = 0; 283 if (mlen == -1) { 284 s_util.c[1] = *(uint8_t *)w; 285 sum += s_util.s; 286 mlen = 0; 287 } else 288 mlen = -1; 289 } else if (mlen == -1) 290 s_util.c[0] = *(uint8_t *)w; 291 } 292 end: 293 if (len) 294 panic("%s: out of data, len %u", __func__, len); 295 if (mlen == -1) { 296 /* The last mbuf has odd # of bytes. Follow the 297 standard (the odd byte may be shifted left by 8 bits 298 or not as determined by endian-ness of the machine) */ 299 s_util.c[1] = 0; 300 sum += s_util.s; 301 } 302 REDUCE; 303 return (~sum & 0xffff); 304} 305