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 #include <sys/param.h> 67 #include <sys/mbuf.h> 68 #include <sys/systm.h> 69 #include <netinet/in.h> 70 #include <netinet/ip6.h> 71 #include <netinet6/scope6_var.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]; (void)ADDCARRY(sum);} 82 83 union l_util { 84 uint16_t s[2]; 85 uint32_t l; 86 }; 87 88 union s_util { 89 uint8_t c[2]; 90 uint16_t s; 91 }; 92 93 static int 94 _in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum) 95 { 96 int sum; 97 uint16_t scope, *w; 98 union { 99 u_int16_t phs[4]; 100 struct { 101 u_int32_t ph_len; 102 u_int8_t ph_zero[3]; 103 u_int8_t ph_nxt; 104 } __packed ph; 105 } uph; 106 107 sum = csum; 108 109 /* 110 * First create IP6 pseudo header and calculate a summary. 111 */ 112 uph.ph.ph_len = htonl(len); 113 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0; 114 uph.ph.ph_nxt = nxt; 115 116 /* Payload length and upper layer identifier. */ 117 sum += uph.phs[0]; sum += uph.phs[1]; 118 sum += uph.phs[2]; sum += uph.phs[3]; 119 120 /* IPv6 source address. */ 121 scope = in6_getscope(&ip6->ip6_src); 122 w = (u_int16_t *)&ip6->ip6_src; 123 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 124 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 125 if (scope != 0) 126 sum -= scope; 127 128 /* IPv6 destination address. */ 129 scope = in6_getscope(&ip6->ip6_dst); 130 w = (u_int16_t *)&ip6->ip6_dst; 131 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 132 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 133 if (scope != 0) 134 sum -= scope; 135 136 return (sum); 137 } 138 139 int 140 in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum) 141 { 142 union l_util l_util; 143 int sum; 144 145 sum = _in6_cksum_pseudo(ip6, len, nxt, csum); 146 REDUCE; 147 return (sum); 148 } 149 150 static int 151 in6_cksumdata(void *data, int *lenp, uint8_t *residp, int rlen) 152 { 153 union l_util l_util; 154 union s_util s_util; 155 uint16_t *w; 156 int len, sum; 157 bool byte_swapped; 158 159 KASSERT(*lenp >= 0, ("%s: negative len %d", __func__, *lenp)); 160 KASSERT(rlen == 0 || rlen == 1, ("%s: rlen %d", __func__, rlen)); 161 162 len = *lenp; 163 sum = 0; 164 165 if (len == 0) { 166 len = rlen; 167 goto out; 168 } 169 170 byte_swapped = false; 171 w = data; 172 173 /* 174 * Do we have a residual byte left over from the previous buffer? 175 */ 176 if (rlen == 1) { 177 s_util.c[0] = *residp; 178 s_util.c[1] = *(uint8_t *)w; 179 sum += s_util.s; 180 w = (uint16_t *)((uint8_t *)w + 1); 181 len--; 182 rlen = 0; 183 } 184 185 /* 186 * Force to even boundary. 187 */ 188 if ((1 & (uintptr_t)w) && len > 0) { 189 REDUCE; 190 sum <<= 8; 191 s_util.c[0] = *(uint8_t *)w; 192 w = (uint16_t *)((uint8_t *)w + 1); 193 len--; 194 byte_swapped = true; 195 } 196 197 /* 198 * Unroll the loop to make overhead from branches &c small. 199 */ 200 while ((len -= 32) >= 0) { 201 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 202 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 203 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; 204 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; 205 w += 16; 206 } 207 len += 32; 208 while ((len -= 8) >= 0) { 209 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 210 w += 4; 211 } 212 len += 8; 213 if (len == 0 && !byte_swapped) 214 goto out; 215 REDUCE; 216 while ((len -= 2) >= 0) { 217 sum += *w++; 218 } 219 if (byte_swapped) { 220 REDUCE; 221 sum <<= 8; 222 if (len == -1) { 223 s_util.c[1] = *(uint8_t *)w; 224 sum += s_util.s; 225 } else /* len == -2 */ 226 *residp = s_util.c[0]; 227 len++; 228 } else if (len == -1) 229 *residp = *(uint8_t *)w; 230 out: 231 *lenp = len & 1; 232 return (sum); 233 } 234 235 struct in6_cksum_partial_arg { 236 int sum; 237 int rlen; 238 uint8_t resid; 239 }; 240 241 static int 242 in6_cksum_partial_one(void *_arg, void *data, u_int len) 243 { 244 struct in6_cksum_partial_arg *arg = _arg; 245 246 arg->sum += in6_cksumdata(data, &len, &arg->resid, arg->rlen); 247 arg->rlen = len; 248 return (0); 249 } 250 251 /* 252 * m MUST contain a contiguous IP6 header. 253 * off is an offset where TCP/UDP/ICMP6 header starts. 254 * len is a total length of a transport segment. 255 * (e.g. TCP header + TCP payload) 256 * cov is the number of bytes to be taken into account for the checksum 257 */ 258 int 259 in6_cksum_partial(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len, 260 uint32_t cov) 261 { 262 struct in6_cksum_partial_arg arg; 263 union l_util l_util; 264 union s_util s_util; 265 struct ip6_hdr *ip6; 266 uint16_t *w, scope; 267 int sum; 268 union { 269 uint16_t phs[4]; 270 struct { 271 uint32_t ph_len; 272 uint8_t ph_zero[3]; 273 uint8_t ph_nxt; 274 } __packed ph; 275 } uph; 276 277 /* Sanity check. */ 278 KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+" 279 "len(%d)", __func__, m->m_pkthdr.len, off, len)); 280 KASSERT(m->m_len >= sizeof(*ip6), 281 ("%s: mbuf len %d < sizeof(ip6)", __func__, m->m_len)); 282 283 /* 284 * First create IP6 pseudo header and calculate a summary. 285 */ 286 uph.ph.ph_len = htonl(len); 287 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0; 288 uph.ph.ph_nxt = nxt; 289 290 /* Payload length and upper layer identifier. */ 291 sum = uph.phs[0]; sum += uph.phs[1]; 292 sum += uph.phs[2]; sum += uph.phs[3]; 293 294 ip6 = mtod(m, struct ip6_hdr *); 295 296 /* IPv6 source address. */ 297 scope = in6_getscope(&ip6->ip6_src); 298 w = (uint16_t *)&ip6->ip6_src; 299 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 300 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 301 if (scope != 0) 302 sum -= scope; 303 304 /* IPv6 destination address. */ 305 scope = in6_getscope(&ip6->ip6_dst); 306 w = (uint16_t *)&ip6->ip6_dst; 307 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; 308 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; 309 if (scope != 0) 310 sum -= scope; 311 312 /* 313 * Loop over the rest of the mbuf chain and compute the rest of the 314 * checksum. m_apply() handles unmapped mbufs. 315 */ 316 arg.sum = sum; 317 arg.rlen = 0; 318 (void)m_apply(m, off, cov, in6_cksum_partial_one, &arg); 319 sum = arg.sum; 320 321 /* 322 * Handle a residual byte. 323 */ 324 if (arg.rlen == 1) { 325 s_util.c[0] = arg.resid; 326 s_util.c[1] = 0; 327 sum += s_util.s; 328 } 329 REDUCE; 330 return (~sum & 0xffff); 331 } 332 333 int 334 in6_cksum(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len) 335 { 336 return (in6_cksum_partial(m, nxt, off, len, len)); 337 } 338