1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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 * $KAME: in6_cksum.c,v 1.10 2000/12/03 00:53:59 itojun Exp $ 32 */ 33 34 /*- 35 * Copyright (c) 1988, 1992, 1993 36 * The Regents of the University of California. All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. Neither the name of the University nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 60 * SUCH DAMAGE. 61 * 62 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 63 */ 64 65 #include <sys/cdefs.h> 66 __FBSDID("$FreeBSD$"); 67 68 #include <sys/param.h> 69 #include <sys/mbuf.h> 70 #include <sys/systm.h> 71 #include <netinet/in.h> 72 #include <netinet/ip6.h> 73 #include <netinet6/scope6_var.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]; (void)ADDCARRY(sum);} 84 85 union l_util { 86 uint16_t s[2]; 87 uint32_t l; 88 }; 89 90 union s_util { 91 uint8_t c[2]; 92 uint16_t s; 93 }; 94 95 static int 96 _in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum) 97 { 98 int sum; 99 uint16_t scope, *w; 100 union { 101 u_int16_t phs[4]; 102 struct { 103 u_int32_t ph_len; 104 u_int8_t ph_zero[3]; 105 u_int8_t ph_nxt; 106 } __packed ph; 107 } uph; 108 109 sum = csum; 110 111 /* 112 * First create IP6 pseudo header and calculate a summary. 113 */ 114 uph.ph.ph_len = htonl(len); 115 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0; 116 uph.ph.ph_nxt = nxt; 117 118 /* Payload length and upper layer identifier. */ 119 sum += uph.phs[0]; sum += uph.phs[1]; 120 sum += uph.phs[2]; sum += uph.phs[3]; 121 122 /* IPv6 source address. */ 123 scope = in6_getscope(&ip6->ip6_src); 124 w = (u_int16_t *)&ip6->ip6_src; 125 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 126 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 127 if (scope != 0) 128 sum -= scope; 129 130 /* IPv6 destination address. */ 131 scope = in6_getscope(&ip6->ip6_dst); 132 w = (u_int16_t *)&ip6->ip6_dst; 133 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 134 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 135 if (scope != 0) 136 sum -= scope; 137 138 return (sum); 139 } 140 141 int 142 in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum) 143 { 144 union l_util l_util; 145 int sum; 146 147 sum = _in6_cksum_pseudo(ip6, len, nxt, csum); 148 REDUCE; 149 return (sum); 150 } 151 152 static int 153 in6_cksumdata(void *data, int *lenp, uint8_t *residp, int rlen) 154 { 155 union l_util l_util; 156 union s_util s_util; 157 uint16_t *w; 158 int len, sum; 159 bool byte_swapped; 160 161 KASSERT(*lenp >= 0, ("%s: negative len %d", __func__, *lenp)); 162 KASSERT(rlen == 0 || rlen == 1, ("%s: rlen %d", __func__, rlen)); 163 164 len = *lenp; 165 sum = 0; 166 167 if (len == 0) { 168 len = rlen; 169 goto out; 170 } 171 172 byte_swapped = false; 173 w = data; 174 175 /* 176 * Do we have a residual byte left over from the previous buffer? 177 */ 178 if (rlen == 1) { 179 s_util.c[0] = *residp; 180 s_util.c[1] = *(uint8_t *)w; 181 sum += s_util.s; 182 w = (uint16_t *)((uint8_t *)w + 1); 183 len--; 184 rlen = 0; 185 } 186 187 /* 188 * Force to even boundary. 189 */ 190 if ((1 & (uintptr_t)w) && len > 0) { 191 REDUCE; 192 sum <<= 8; 193 s_util.c[0] = *(uint8_t *)w; 194 w = (uint16_t *)((uint8_t *)w + 1); 195 len--; 196 byte_swapped = true; 197 } 198 199 /* 200 * Unroll the loop to make overhead from branches &c small. 201 */ 202 while ((len -= 32) >= 0) { 203 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 204 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 205 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 206 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 207 w += 16; 208 } 209 len += 32; 210 while ((len -= 8) >= 0) { 211 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 212 w += 4; 213 } 214 len += 8; 215 if (len == 0 && !byte_swapped) 216 goto out; 217 REDUCE; 218 while ((len -= 2) >= 0) { 219 sum += *w++; 220 } 221 if (byte_swapped) { 222 REDUCE; 223 sum <<= 8; 224 if (len == -1) { 225 s_util.c[1] = *(uint8_t *)w; 226 sum += s_util.s; 227 } else /* len == -2 */ 228 *residp = s_util.c[0]; 229 len++; 230 } else if (len == -1) 231 *residp = *(uint8_t *)w; 232 out: 233 *lenp = len & 1; 234 return (sum); 235 } 236 237 struct in6_cksum_partial_arg { 238 int sum; 239 int rlen; 240 uint8_t resid; 241 }; 242 243 static int 244 in6_cksum_partial_one(void *_arg, void *data, u_int len) 245 { 246 struct in6_cksum_partial_arg *arg = _arg; 247 248 arg->sum += in6_cksumdata(data, &len, &arg->resid, arg->rlen); 249 arg->rlen = len; 250 return (0); 251 } 252 253 /* 254 * m MUST contain a contiguous IP6 header. 255 * off is an offset where TCP/UDP/ICMP6 header starts. 256 * len is a total length of a transport segment. 257 * (e.g. TCP header + TCP payload) 258 * cov is the number of bytes to be taken into account for the checksum 259 */ 260 int 261 in6_cksum_partial(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len, 262 uint32_t cov) 263 { 264 struct in6_cksum_partial_arg arg; 265 union l_util l_util; 266 union s_util s_util; 267 struct ip6_hdr *ip6; 268 uint16_t *w, scope; 269 int sum; 270 union { 271 uint16_t phs[4]; 272 struct { 273 uint32_t ph_len; 274 uint8_t ph_zero[3]; 275 uint8_t ph_nxt; 276 } __packed ph; 277 } uph; 278 279 /* Sanity check. */ 280 KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+" 281 "len(%d)", __func__, m->m_pkthdr.len, off, len)); 282 KASSERT(m->m_len >= sizeof(*ip6), 283 ("%s: mbuf len %d < sizeof(ip6)", __func__, m->m_len)); 284 285 /* 286 * First create IP6 pseudo header and calculate a summary. 287 */ 288 uph.ph.ph_len = htonl(len); 289 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0; 290 uph.ph.ph_nxt = nxt; 291 292 /* Payload length and upper layer identifier. */ 293 sum = uph.phs[0]; sum += uph.phs[1]; 294 sum += uph.phs[2]; sum += uph.phs[3]; 295 296 ip6 = mtod(m, struct ip6_hdr *); 297 298 /* IPv6 source address. */ 299 scope = in6_getscope(&ip6->ip6_src); 300 w = (uint16_t *)&ip6->ip6_src; 301 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 302 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 303 if (scope != 0) 304 sum -= scope; 305 306 /* IPv6 destination address. */ 307 scope = in6_getscope(&ip6->ip6_dst); 308 w = (uint16_t *)&ip6->ip6_dst; 309 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 310 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 311 if (scope != 0) 312 sum -= scope; 313 314 /* 315 * Loop over the rest of the mbuf chain and compute the rest of the 316 * checksum. m_apply() handles unmapped mbufs. 317 */ 318 arg.sum = sum; 319 arg.rlen = 0; 320 (void)m_apply(m, off, cov, in6_cksum_partial_one, &arg); 321 sum = arg.sum; 322 323 /* 324 * Handle a residual byte. 325 */ 326 if (arg.rlen == 1) { 327 s_util.c[0] = arg.resid; 328 s_util.c[1] = 0; 329 sum += s_util.s; 330 } 331 REDUCE; 332 return (~sum & 0xffff); 333 } 334 335 int 336 in6_cksum(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len) 337 { 338 return (in6_cksum_partial(m, nxt, off, len, len)); 339 } 340