1 /* $NetBSD: mpls_ttl.c,v 1.15 2018/12/27 14:03:55 maxv 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 1.15 2018/12/27 14:03:55 maxv 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 #define MPLS_STACK_ENTRY_CLASS 1 134 #define MPLS_STACK_ENTRY_C_TYPE 1 135 136 struct mpls_extension { 137 struct icmp_ext_hdr cmn_hdr; 138 struct icmp_ext_obj_hdr obj_hdr; 139 union mpls_shim ms; 140 } __packed; 141 142 static void mpls_icmp_error(struct mbuf *, int, int, n_long, int, 143 union mpls_shim *); 144 static struct mbuf *ip4_check(struct mbuf *); 145 146 /* 147 * Send an ICMP Extended error message. References: RFC4884 and RFC4950. 148 * 149 * XXX: This code is inspired from icmp_error(), and should really be merged 150 * into it. icmp_error() should handle ICMP Extended error messages. 151 * 152 * XXX: It is called only for ICMP_TIMXCEED_INTRANS but code is too general. 153 * 154 * XXX: We're not setting the 'length' field of the Extended ICMP header. 155 * According to RFC4884, we are in 'non-compliant' mode. Moreover, we're 156 * not computing the checksum of the Extended ICMP header. 157 */ 158 static void 159 mpls_icmp_error(struct mbuf *n, int type, int code, n_long dest, 160 int destmtu, union mpls_shim *shim) 161 { 162 struct ip *oip = mtod(n, struct ip *), *nip; 163 unsigned oiplen = oip->ip_hl << 2; 164 struct icmp *icp; 165 struct mbuf *m; 166 unsigned icmplen, mblen, packetlen; 167 struct mpls_extension mpls_icmp_ext; 168 169 memset(&mpls_icmp_ext, 0, sizeof(mpls_icmp_ext)); 170 mpls_icmp_ext.cmn_hdr.version = ICMP_EXT_VERSION; 171 mpls_icmp_ext.cmn_hdr.checksum = 0; /* XXX */ 172 173 mpls_icmp_ext.obj_hdr.length = htons(sizeof(union mpls_shim) + 174 sizeof(struct icmp_ext_obj_hdr)); 175 mpls_icmp_ext.obj_hdr.class_num = MPLS_STACK_ENTRY_CLASS; 176 mpls_icmp_ext.obj_hdr.c_type = MPLS_STACK_ENTRY_C_TYPE; 177 178 mpls_icmp_ext.ms.s_addr = shim->s_addr; 179 180 if (type != ICMP_REDIRECT) 181 ICMP_STATINC(ICMP_STAT_ERROR); 182 183 /* 184 * Don't send error if the original packet was encrypted. 185 * Don't send error if not the first fragment of message. 186 * Don't error if the old packet protocol was ICMP 187 * error message, only known informational types. 188 */ 189 if (n->m_flags & M_DECRYPTED) 190 goto freeit; 191 if (oip->ip_off &~ htons(IP_MF|IP_DF)) 192 goto freeit; 193 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 194 n->m_len >= oiplen + ICMP_MINLEN && 195 !ICMP_INFOTYPE(((struct icmp *)((char *)oip + oiplen))->icmp_type)) 196 { 197 ICMP_STATINC(ICMP_STAT_OLDICMP); 198 goto freeit; 199 } 200 201 /* Don't send error in response to a multicast or broadcast packet */ 202 if (n->m_flags & (M_BCAST|M_MCAST)) 203 goto freeit; 204 205 /* 206 * First, do a rate limitation check. 207 */ 208 if (icmp_ratelimit(&oip->ip_src, type, code)) 209 /* XXX stats */ 210 goto freeit; 211 212 /* 213 * Now, formulate icmp message 214 */ 215 icmplen = uimin(ICMP_EXT_OFFSET, ntohs(oip->ip_len)); 216 217 /* 218 * Defend against mbuf chains shorter than oip->ip_len - oiplen: 219 */ 220 mblen = 0; 221 for (m = n; m && (mblen < icmplen); m = m->m_next) 222 mblen += m->m_len; 223 icmplen = uimin(mblen, icmplen); 224 225 packetlen = sizeof(struct ip) + offsetof(struct icmp, icmp_ip) + 226 ICMP_EXT_OFFSET + sizeof(mpls_icmp_ext); 227 228 /* 229 * As we are not required to return everything we have, 230 * we return whatever we can return at ease. 231 * 232 * Note that ICMP datagrams longer than 576 octets are out of spec 233 * according to RFC1812; the limit on icmpreturndatabytes below in 234 * icmp_sysctl will keep things below that limit. 235 */ 236 237 KASSERT(packetlen <= MCLBYTES); 238 239 m = m_gethdr(M_DONTWAIT, MT_HEADER); 240 if (m && (packetlen > MHLEN)) { 241 MCLGET(m, M_DONTWAIT); 242 if ((m->m_flags & M_EXT) == 0) { 243 m_freem(m); 244 m = NULL; 245 } 246 } 247 if (m == NULL) 248 goto freeit; 249 250 MCLAIM(m, n->m_owner); 251 m->m_len = packetlen; 252 if ((m->m_flags & M_EXT) == 0) 253 m_align(m, m->m_len); 254 m->m_data += sizeof(struct ip); 255 m->m_len -= sizeof(struct ip); 256 257 icp = mtod(m, struct icmp *); 258 if ((u_int)type > ICMP_MAXTYPE) 259 panic("icmp error (mpls_ttl)"); 260 ICMP_STATINC(ICMP_STAT_OUTHIST + type); 261 icp->icmp_type = type; 262 if (type == ICMP_REDIRECT) 263 icp->icmp_gwaddr.s_addr = dest; 264 else { 265 icp->icmp_void = 0; 266 /* 267 * The following assignments assume an overlay with the 268 * zeroed icmp_void field. 269 */ 270 if (type == ICMP_PARAMPROB) { 271 icp->icmp_pptr = code; 272 code = 0; 273 } else if (type == ICMP_UNREACH && 274 code == ICMP_UNREACH_NEEDFRAG && destmtu) 275 icp->icmp_nextmtu = htons(destmtu); 276 } 277 278 icp->icmp_code = code; 279 280 memset(&icp->icmp_ip, 0, ICMP_EXT_OFFSET); 281 m_copydata(n, 0, icmplen, (char *)&icp->icmp_ip); 282 283 /* Append the extension structure */ 284 memcpy(((char*)&icp->icmp_ip) + ICMP_EXT_OFFSET, 285 &mpls_icmp_ext, sizeof(mpls_icmp_ext)); 286 287 /* 288 * Now, copy old ip header (without options) 289 * in front of icmp message. 290 */ 291 if ((m->m_flags & M_EXT) == 0 && 292 m->m_data - sizeof(struct ip) < m->m_pktdat) 293 panic("icmp len"); 294 m->m_data -= sizeof(struct ip); 295 m->m_len += sizeof(struct ip); 296 m->m_pkthdr.len = m->m_len; 297 m_copy_rcvif(m, n); 298 nip = mtod(m, struct ip *); 299 /* ip_v set in ip_output */ 300 nip->ip_hl = sizeof(struct ip) >> 2; 301 nip->ip_tos = 0; 302 nip->ip_len = htons(m->m_len); 303 /* ip_id set in ip_output */ 304 nip->ip_off = htons(0); 305 /* ip_ttl set in icmp_reflect */ 306 nip->ip_p = IPPROTO_ICMP; 307 nip->ip_src = oip->ip_src; 308 nip->ip_dst = oip->ip_dst; 309 icmp_reflect(m); 310 311 freeit: 312 m_freem(n); 313 } 314 315 static struct mbuf * 316 ip4_check(struct mbuf *m) 317 { 318 struct ip *iph; 319 int hlen, len; 320 321 if (m->m_len < sizeof(struct ip) && 322 (m = m_pullup(m, sizeof(struct ip))) == NULL) 323 return NULL; 324 325 iph = mtod(m, struct ip *); 326 327 if (iph->ip_v != IPVERSION) 328 goto freeit; 329 hlen = iph->ip_hl << 2; 330 if (hlen < sizeof(struct ip)) 331 goto freeit; 332 if (hlen > m->m_len) { 333 if ((m = m_pullup(m, hlen)) == NULL) 334 return NULL; 335 iph = mtod(m, struct ip *); 336 } 337 338 /* 339 * RFC1122: packets with a multicast source address are 340 * not allowed. 341 * RFC1122: 127/8 must not appear on wire. 342 */ 343 if (IN_MULTICAST(iph->ip_src.s_addr) || 344 (ntohl(iph->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 345 (ntohl(iph->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 346 in_cksum(m, hlen) != 0) 347 goto freeit; 348 349 len = ntohs(iph->ip_len); 350 if (len < hlen || m->m_pkthdr.len < len) 351 goto freeit; 352 353 return m; 354 355 freeit: 356 m_freem(m); 357 return NULL; 358 } 359 #endif /* INET */ 360 361 struct mbuf * 362 mpls_ttl_dec(struct mbuf *m) 363 { 364 union mpls_shim *mshim; 365 #ifdef INET 366 union mpls_shim top_shim, bos_shim; 367 #endif 368 369 if (__predict_false(m->m_len < sizeof(union mpls_shim) && 370 (m = m_pullup(m, sizeof(union mpls_shim))) == NULL)) 371 return NULL; 372 mshim = mtod(m, union mpls_shim *); 373 mshim->s_addr = ntohl(mshim->s_addr); 374 mshim->shim.ttl--; 375 376 if (mshim->shim.ttl == 0) { 377 if (!mpls_icmp_respond) { 378 m_freem(m); 379 return NULL; 380 } 381 382 #ifdef INET 383 /* 384 * Shim ttl exceeded. Send back ICMP type 11 code 0. 385 */ 386 bos_shim.s_addr = mshim->s_addr; 387 top_shim.s_addr = htonl(mshim->s_addr); 388 m_adj(m, sizeof(union mpls_shim)); 389 390 /* Goto BOS */ 391 while (bos_shim.shim.bos == 0) { 392 if (m->m_len < sizeof(union mpls_shim) && 393 (m = m_pullup(m, sizeof(union mpls_shim))) == NULL) { 394 m_freem(m); 395 return NULL; 396 } 397 bos_shim.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr); 398 m_adj(m, sizeof(union mpls_shim)); 399 } 400 401 if ((m = ip4_check(m)) != NULL) 402 mpls_icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 403 0, 0, &top_shim); 404 #else 405 m_freem(m); 406 #endif 407 return NULL; 408 } 409 410 mshim->s_addr = htonl(mshim->s_addr); 411 412 return m; 413 } 414
Indexes created Sun Sep 21 19:09:51 GMT 2025