mpls_ttl.c revision 1.8.10.1
1 /* $NetBSD: mpls_ttl.c,v 1.8.10.1 2018/02/12 18:18:00 snj Exp $ */ 2 3 /* 4 * Copyright (c) 2010 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Public Access Networks Corporation ("Panix"). It was developed under 9 * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon. 10 * 11 * This code is derived from software contributed to The NetBSD Foundation 12 * by Jason R. Thorpe of Zembu Labs, Inc. 13 * 14 * This code is derived from software contributed to The NetBSD Foundation 15 * by Mihai Chelaru <kefren (at) NetBSD.org> 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 41 * All rights reserved. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. Neither the name of the project nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 */ 67 68 /* 69 * Copyright (c) 1982, 1986, 1988, 1993 70 * The Regents of the University of California. All rights reserved. 71 * 72 * Redistribution and use in source and binary forms, with or without 73 * modification, are permitted provided that the following conditions 74 * are met: 75 * 1. Redistributions of source code must retain the above copyright 76 * notice, this list of conditions and the following disclaimer. 77 * 2. Redistributions in binary form must reproduce the above copyright 78 * notice, this list of conditions and the following disclaimer in the 79 * documentation and/or other materials provided with the distribution. 80 * 3. Neither the name of the University nor the names of its contributors 81 * may be used to endorse or promote products derived from this software 82 * without specific prior written permission. 83 * 84 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 85 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 86 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 87 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 88 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 89 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 90 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 91 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 92 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 93 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 94 * SUCH DAMAGE. 95 * 96 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 97 */ 98 99 #include <sys/cdefs.h> 100 __KERNEL_RCSID(0, "$NetBSD: mpls_ttl.c,v 1.8.10.1 2018/02/12 18:18:00 snj Exp $"); 101 102 #ifdef _KERNEL_OPT 103 #include "opt_inet.h" 104 #include "opt_mpls.h" 105 #endif 106 107 #include <sys/param.h> 108 #include <sys/malloc.h> 109 #include <sys/mbuf.h> 110 #include <sys/errno.h> 111 #include <sys/socket.h> 112 #include <sys/systm.h> 113 114 #include <net/if.h> 115 #include <net/if_dl.h> 116 117 #include <netinet/in.h> 118 #include <netinet/in_systm.h> 119 #include <netinet/ip.h> 120 #include <netinet/ip_icmp.h> 121 #include <netinet/icmp_private.h> 122 #include <netinet/icmp_var.h> 123 124 #include <netmpls/mpls.h> 125 #include <netmpls/mpls_var.h> 126 127 #ifdef INET 128 129 /* in netinet/ip_icmp.c */ 130 extern int icmpreturndatabytes; 131 132 /* ICMP Extensions */ 133 134 #define ICMP_EXT_VERSION 2 135 #define MPLS_RETURN_DATA 128 136 #define ICMP_EXT_OFFSET 128 137 138 struct icmp_ext_cmn_hdr { 139 #if BYTE_ORDER == BIG_ENDIAN 140 unsigned char version:4; 141 unsigned char reserved1:4; 142 #else 143 unsigned char reserved1:4; 144 unsigned char version:4; 145 #endif 146 unsigned char reserved2; 147 unsigned short checksum; 148 }; 149 150 struct icmp_ext_obj_hdr { 151 u_short length; 152 u_char class_num; 153 #define MPLS_STACK_ENTRY_CLASS 1 154 u_char c_type; 155 #define MPLS_STACK_ENTRY_C_TYPE 1 156 }; 157 158 struct mpls_extension { 159 struct icmp_ext_cmn_hdr cmn_hdr; 160 struct icmp_ext_obj_hdr obj_hdr; 161 union mpls_shim ms; 162 } __packed; 163 164 static void mpls_icmp_error(struct mbuf *, int, int, n_long, int, 165 union mpls_shim *); 166 static struct mbuf *ip4_check(struct mbuf *); 167 168 /* 169 * Send an ICMP Extended error message. References: RFC4884 and RFC4950. 170 * 171 * This should be in sync with icmp_error() in sys/netinet/ip_icmp.c 172 * XXX: is called only for ICMP_TIMXCEED_INTRANS but code is too general. 173 * 174 * XXX We're not setting the 'length' field of the Extended ICMP header. 175 * According to RFC4884, we are in 'non-compliant' mode. Moreover, we're 176 * not computing the checksum of the Extended ICMP header. 177 */ 178 static void 179 mpls_icmp_error(struct mbuf *n, int type, int code, n_long dest, 180 int destmtu, union mpls_shim *shim) 181 { 182 struct ip *oip = mtod(n, struct ip *), *nip; 183 unsigned oiplen = oip->ip_hl << 2; 184 struct icmp *icp; 185 struct mbuf *m; 186 unsigned icmplen, mblen, packetlen; 187 struct mpls_extension mpls_icmp_ext; 188 189 memset(&mpls_icmp_ext, 0, sizeof(mpls_icmp_ext)); 190 mpls_icmp_ext.cmn_hdr.version = ICMP_EXT_VERSION; 191 mpls_icmp_ext.cmn_hdr.checksum = 0; /* XXX */ 192 193 mpls_icmp_ext.obj_hdr.length = htons(sizeof(union mpls_shim) + 194 sizeof(struct icmp_ext_obj_hdr)); 195 mpls_icmp_ext.obj_hdr.class_num = MPLS_STACK_ENTRY_CLASS; 196 mpls_icmp_ext.obj_hdr.c_type = MPLS_STACK_ENTRY_C_TYPE; 197 198 mpls_icmp_ext.ms.s_addr = shim->s_addr; 199 200 #ifdef ICMPPRINTFS 201 if (icmpprintfs) 202 printf("mpls_icmp_error(%p, type:%d, code:%d)\n", oip, type, 203 code); 204 #endif 205 if (type != ICMP_REDIRECT) 206 ICMP_STATINC(ICMP_STAT_ERROR); 207 208 /* 209 * Don't send error if the original packet was encrypted. 210 * Don't send error if not the first fragment of message. 211 * Don't error if the old packet protocol was ICMP 212 * error message, only known informational types. 213 */ 214 if (n->m_flags & M_DECRYPTED) 215 goto freeit; 216 if (oip->ip_off &~ htons(IP_MF|IP_DF)) 217 goto freeit; 218 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 219 n->m_len >= oiplen + ICMP_MINLEN && 220 !ICMP_INFOTYPE(((struct icmp *)((char *)oip + oiplen))->icmp_type)) 221 { 222 ICMP_STATINC(ICMP_STAT_OLDICMP); 223 goto freeit; 224 } 225 226 /* Don't send error in response to a multicast or broadcast packet */ 227 if (n->m_flags & (M_BCAST|M_MCAST)) 228 goto freeit; 229 230 /* 231 * First, do a rate limitation check. 232 */ 233 if (icmp_ratelimit(&oip->ip_src, type, code)) 234 /* XXX stats */ 235 goto freeit; 236 237 /* 238 * Now, formulate icmp message 239 */ 240 icmplen = min(ICMP_EXT_OFFSET, ntohs(oip->ip_len)); 241 242 /* 243 * Defend against mbuf chains shorter than oip->ip_len - oiplen: 244 */ 245 mblen = 0; 246 for (m = n; m && (mblen < icmplen); m = m->m_next) 247 mblen += m->m_len; 248 icmplen = min(mblen, icmplen); 249 250 packetlen = sizeof(struct ip) + offsetof(struct icmp, icmp_ip) + 251 ICMP_EXT_OFFSET + sizeof(mpls_icmp_ext); 252 253 /* 254 * As we are not required to return everything we have, 255 * we return whatever we can return at ease. 256 * 257 * Note that ICMP datagrams longer than 576 octets are out of spec 258 * according to RFC1812; the limit on icmpreturndatabytes below in 259 * icmp_sysctl will keep things below that limit. 260 */ 261 262 KASSERT(packetlen <= MCLBYTES); 263 264 m = m_gethdr(M_DONTWAIT, MT_HEADER); 265 if (m && (packetlen > MHLEN)) { 266 MCLGET(m, M_DONTWAIT); 267 if ((m->m_flags & M_EXT) == 0) { 268 m_freem(m); 269 m = NULL; 270 } 271 } 272 if (m == NULL) 273 goto freeit; 274 275 MCLAIM(m, n->m_owner); 276 m->m_len = packetlen; 277 if ((m->m_flags & M_EXT) == 0) 278 MH_ALIGN(m, m->m_len); 279 m->m_data += sizeof(struct ip); 280 m->m_len -= sizeof(struct ip); 281 282 icp = mtod(m, struct icmp *); 283 if ((u_int)type > ICMP_MAXTYPE) 284 panic("icmp error (mpls_ttl)"); 285 ICMP_STATINC(ICMP_STAT_OUTHIST + type); 286 icp->icmp_type = type; 287 if (type == ICMP_REDIRECT) 288 icp->icmp_gwaddr.s_addr = dest; 289 else { 290 icp->icmp_void = 0; 291 /* 292 * The following assignments assume an overlay with the 293 * zeroed icmp_void field. 294 */ 295 if (type == ICMP_PARAMPROB) { 296 icp->icmp_pptr = code; 297 code = 0; 298 } else if (type == ICMP_UNREACH && 299 code == ICMP_UNREACH_NEEDFRAG && destmtu) 300 icp->icmp_nextmtu = htons(destmtu); 301 } 302 303 icp->icmp_code = code; 304 305 memset(&icp->icmp_ip, 0, ICMP_EXT_OFFSET); 306 m_copydata(n, 0, icmplen, (char *)&icp->icmp_ip); 307 308 /* Append the extension structure */ 309 memcpy(((char*)&icp->icmp_ip) + ICMP_EXT_OFFSET, 310 &mpls_icmp_ext, sizeof(mpls_icmp_ext)); 311 312 /* 313 * Now, copy old ip header (without options) 314 * in front of icmp message. 315 */ 316 if ((m->m_flags & M_EXT) == 0 && 317 m->m_data - sizeof(struct ip) < m->m_pktdat) 318 panic("icmp len"); 319 m->m_data -= sizeof(struct ip); 320 m->m_len += sizeof(struct ip); 321 m->m_pkthdr.len = m->m_len; 322 m_copy_rcvif(m, n); 323 nip = mtod(m, struct ip *); 324 /* ip_v set in ip_output */ 325 nip->ip_hl = sizeof(struct ip) >> 2; 326 nip->ip_tos = 0; 327 nip->ip_len = htons(m->m_len); 328 /* ip_id set in ip_output */ 329 nip->ip_off = htons(0); 330 /* ip_ttl set in icmp_reflect */ 331 nip->ip_p = IPPROTO_ICMP; 332 nip->ip_src = oip->ip_src; 333 nip->ip_dst = oip->ip_dst; 334 icmp_reflect(m); 335 336 freeit: 337 m_freem(n); 338 } 339 340 static struct mbuf * 341 ip4_check(struct mbuf *m) 342 { 343 struct ip *iph; 344 int hlen, len; 345 346 if (m->m_len < sizeof(struct ip) && 347 (m = m_pullup(m, sizeof(struct ip))) == NULL) 348 return NULL; 349 350 iph = mtod(m, struct ip *); 351 352 if (iph->ip_v != IPVERSION) 353 goto freeit; 354 hlen = iph->ip_hl << 2; 355 if (hlen < sizeof(struct ip)) 356 goto freeit; 357 if (hlen > m->m_len) { 358 if ((m = m_pullup(m, hlen)) == NULL) 359 return NULL; 360 iph = mtod(m, struct ip *); 361 } 362 363 /* 364 * RFC1122: packets with a multicast source address are 365 * not allowed. 366 * RFC1122: 127/8 must not appear on wire. 367 */ 368 if (IN_MULTICAST(iph->ip_src.s_addr) || 369 (ntohl(iph->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 370 (ntohl(iph->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 371 in_cksum(m, hlen) != 0) 372 goto freeit; 373 374 len = ntohs(iph->ip_len); 375 if (len < hlen || m->m_pkthdr.len < len) 376 goto freeit; 377 378 return m; 379 380 freeit: 381 m_freem(m); 382 return NULL; 383 } 384 #endif /* INET */ 385 386 struct mbuf * 387 mpls_ttl_dec(struct mbuf *m) 388 { 389 union mpls_shim *mshim; 390 #ifdef INET 391 union mpls_shim top_shim, bos_shim; 392 #endif 393 394 if (__predict_false(m->m_len < sizeof(union mpls_shim) && 395 (m = m_pullup(m, sizeof(union mpls_shim))) == NULL)) 396 return NULL; 397 mshim = mtod(m, union mpls_shim *); 398 mshim->s_addr = ntohl(mshim->s_addr); 399 mshim->shim.ttl--; 400 401 if (mshim->shim.ttl == 0) { 402 if (!mpls_icmp_respond) { 403 m_freem(m); 404 return NULL; 405 } 406 407 #ifdef INET 408 /* 409 * Shim ttl exceeded. Send back ICMP type 11 code 0. 410 */ 411 bos_shim.s_addr = mshim->s_addr; 412 top_shim.s_addr = htonl(mshim->s_addr); 413 m_adj(m, sizeof(union mpls_shim)); 414 415 /* Goto BOS */ 416 while (bos_shim.shim.bos == 0) { 417 if (m->m_len < sizeof(union mpls_shim) && 418 (m = m_pullup(m, sizeof(union mpls_shim))) == NULL) { 419 m_freem(m); 420 return NULL; 421 } 422 bos_shim.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr); 423 m_adj(m, sizeof(union mpls_shim)); 424 } 425 426 if ((m = ip4_check(m)) != NULL) 427 mpls_icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 428 0, 0, &top_shim); 429 #else 430 m_freem(m); 431 #endif 432 return NULL; 433 } 434 435 mshim->s_addr = htonl(mshim->s_addr); 436 437 return m; 438 } 439
Indexes created Tue Sep 23 02:09:52 GMT 2025