mpls_ttl.c revision 1.4.4.1
1 /* $NetBSD: mpls_ttl.c,v 1.4.4.1 2018/02/24 18:29:41 snj Exp $ */ 2 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 32 /* 33 * Copyright (c) 2010 The NetBSD Foundation, Inc. 34 * All rights reserved. 35 * 36 * This code is derived from software contributed to The NetBSD Foundation 37 * by Public Access Networks Corporation ("Panix"). It was developed under 38 * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon. 39 * 40 * This code is derived from software contributed to The NetBSD Foundation 41 * by Jason R. Thorpe of Zembu Labs, Inc. 42 * 43 * This code is derived from software contributed to The NetBSD Foundation 44 * by Mihai Chelaru <kefren (at) NetBSD.org> 45 * 46 * Redistribution and use in source and binary forms, with or without 47 * modification, are permitted provided that the following conditions 48 * are met: 49 * 1. Redistributions of source code must retain the above copyright 50 * notice, this list of conditions and the following disclaimer. 51 * 2. Redistributions in binary form must reproduce the above copyright 52 * notice, this list of conditions and the following disclaimer in the 53 * documentation and/or other materials provided with the distribution. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 56 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 57 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 58 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 59 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 60 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 61 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 62 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 63 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 64 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 65 * POSSIBILITY OF 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 1.4.4.1 2018/02/24 18:29:41 snj Exp $"); 101 102 #include "opt_inet.h" 103 #include "opt_mpls.h" 104 105 #include <sys/param.h> 106 #include <sys/malloc.h> 107 #include <sys/mbuf.h> 108 #include <sys/errno.h> 109 #include <sys/socket.h> 110 #include <sys/systm.h> 111 112 #include <net/if.h> 113 #include <net/if_dl.h> 114 #include <net/route.h> 115 116 #include <netinet/in.h> 117 #include <netinet/in_systm.h> 118 #include <netinet/ip.h> 119 #include <netinet/ip_icmp.h> 120 #include <netinet/icmp_private.h> 121 #include <netinet/icmp_var.h> 122 123 #include <netmpls/mpls.h> 124 #include <netmpls/mpls_var.h> 125 126 #ifdef INET 127 128 /* in netinet/ip_icmp.c */ 129 extern int icmpreturndatabytes; 130 131 /* ICMP Extensions */ 132 133 #define ICMP_EXT_VERSION 2 134 #define MPLS_RETURN_DATA 128 135 #define ICMP_EXT_OFFSET 128 136 137 struct icmp_ext_cmn_hdr { 138 #if BYTE_ORDER == BIG_ENDIAN 139 unsigned char version:4; 140 unsigned char reserved1:4; 141 #else 142 unsigned char reserved1:4; 143 unsigned char version:4; 144 #endif 145 unsigned char reserved2; 146 unsigned short checksum; 147 }; 148 149 struct icmp_ext_obj_hdr { 150 u_short length; 151 u_char class_num; 152 #define MPLS_STACK_ENTRY_CLASS 1 153 u_char c_type; 154 #define MPLS_STACK_ENTRY_C_TYPE 1 155 }; 156 157 struct mpls_extension { 158 struct icmp_ext_cmn_hdr cmn_hdr; 159 struct icmp_ext_obj_hdr obj_hdr; 160 union mpls_shim ms; 161 } __packed; 162 163 static void mpls_icmp_error(struct mbuf *, int, int, n_long, int, 164 union mpls_shim *); 165 static struct mbuf *ip4_check(struct mbuf *); 166 167 /* 168 * References: RFC 4884 and RFC 4950 169 * This should be in sync with icmp_error() in sys/netinet/ip_icmp.c 170 * XXX: is called only for ICMP_TIMXCEED_INTRANS but code is too general 171 */ 172 173 static void 174 mpls_icmp_error(struct mbuf *n, int type, int code, n_long dest, 175 int destmtu, union mpls_shim *shim) 176 { 177 struct ip *oip = mtod(n, struct ip *), *nip; 178 unsigned oiplen = oip->ip_hl << 2; 179 struct icmp *icp; 180 struct mbuf *m; 181 unsigned icmplen, mblen, packetlen; 182 struct mpls_extension mpls_icmp_ext; 183 184 memset(&mpls_icmp_ext, 0, sizeof(mpls_icmp_ext)); 185 mpls_icmp_ext.cmn_hdr.version = ICMP_EXT_VERSION; 186 mpls_icmp_ext.cmn_hdr.checksum = 0; 187 188 mpls_icmp_ext.obj_hdr.length = htons(sizeof(union mpls_shim) + 189 sizeof(struct icmp_ext_obj_hdr)); 190 mpls_icmp_ext.obj_hdr.class_num = MPLS_STACK_ENTRY_CLASS; 191 mpls_icmp_ext.obj_hdr.c_type = MPLS_STACK_ENTRY_C_TYPE; 192 193 mpls_icmp_ext.ms.s_addr = shim->s_addr; 194 195 #ifdef ICMPPRINTFS 196 if (icmpprintfs) 197 printf("mpls_icmp_error(%p, type:%d, code:%d)\n", oip, type, 198 code); 199 #endif 200 if (type != ICMP_REDIRECT) 201 ICMP_STATINC(ICMP_STAT_ERROR); 202 /* 203 * Don't send error if the original packet was encrypted. 204 * Don't send error if not the first fragment of message. 205 * Don't error if the old packet protocol was ICMP 206 * error message, only known informational types. 207 */ 208 if (n->m_flags & M_DECRYPTED) 209 goto freeit; 210 if (oip->ip_off &~ htons(IP_MF|IP_DF)) 211 goto freeit; 212 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 213 n->m_len >= oiplen + ICMP_MINLEN && 214 !ICMP_INFOTYPE(((struct icmp *)((char *)oip + oiplen))->icmp_type)) 215 { 216 ICMP_STATINC(ICMP_STAT_OLDICMP); 217 goto freeit; 218 } 219 /* Don't send error in response to a multicast or broadcast packet */ 220 if (n->m_flags & (M_BCAST|M_MCAST)) 221 goto freeit; 222 223 /* 224 * First, do a rate limitation check. 225 */ 226 if (icmp_ratelimit(&oip->ip_src, type, code)) 227 /* XXX stats */ 228 goto freeit; 229 230 /* 231 * Now, formulate icmp message 232 */ 233 icmplen = min(ICMP_EXT_OFFSET, ntohs(oip->ip_len)); 234 /* 235 * Defend against mbuf chains shorter than oip->ip_len - oiplen: 236 */ 237 mblen = 0; 238 for (m = n; m && (mblen < icmplen); m = m->m_next) 239 mblen += m->m_len; 240 icmplen = min(mblen, icmplen); 241 242 packetlen = sizeof(struct ip) + offsetof(struct icmp, icmp_ip) + 243 ICMP_EXT_OFFSET + sizeof(mpls_icmp_ext); 244 245 /* 246 * As we are not required to return everything we have, 247 * we return whatever we can return at ease. 248 * 249 * Note that ICMP datagrams longer than 576 octets are out of spec 250 * according to RFC1812; the limit on icmpreturndatabytes below in 251 * icmp_sysctl will keep things below that limit. 252 */ 253 254 KASSERT (packetlen <= MCLBYTES); 255 256 m = m_gethdr(M_DONTWAIT, MT_HEADER); 257 if (m && (packetlen > MHLEN)) { 258 MCLGET(m, M_DONTWAIT); 259 if ((m->m_flags & M_EXT) == 0) { 260 m_freem(m); 261 m = NULL; 262 } 263 } 264 if (m == NULL) 265 goto freeit; 266 MCLAIM(m, n->m_owner); 267 m->m_len = packetlen; 268 if ((m->m_flags & M_EXT) == 0) 269 MH_ALIGN(m, m->m_len); 270 m->m_data += sizeof(struct ip); 271 m->m_len -= sizeof(struct ip); 272 273 icp = mtod(m, struct icmp *); 274 if ((u_int)type > ICMP_MAXTYPE) 275 panic("icmp error (mpls_ttl)"); 276 ICMP_STATINC(ICMP_STAT_OUTHIST + type); 277 icp->icmp_type = type; 278 if (type == ICMP_REDIRECT) 279 icp->icmp_gwaddr.s_addr = dest; 280 else { 281 icp->icmp_void = 0; 282 /* 283 * The following assignments assume an overlay with the 284 * zeroed icmp_void field. 285 */ 286 if (type == ICMP_PARAMPROB) { 287 icp->icmp_pptr = code; 288 code = 0; 289 } else if (type == ICMP_UNREACH && 290 code == ICMP_UNREACH_NEEDFRAG && destmtu) 291 icp->icmp_nextmtu = htons(destmtu); 292 } 293 294 icp->icmp_code = code; 295 296 memset(&icp->icmp_ip, 0, ICMP_EXT_OFFSET); 297 m_copydata(n, 0, icmplen, (char *)&icp->icmp_ip); 298 299 /* Append the extension structure */ 300 memcpy(((char*)&icp->icmp_ip) + ICMP_EXT_OFFSET, 301 &mpls_icmp_ext, sizeof(mpls_icmp_ext)); 302 303 /* 304 * Now, copy old ip header (without options) 305 * in front of icmp message. 306 */ 307 if ((m->m_flags & M_EXT) == 0 && 308 m->m_data - sizeof(struct ip) < m->m_pktdat) 309 panic("icmp len"); 310 m->m_data -= sizeof(struct ip); 311 m->m_len += sizeof(struct ip); 312 m->m_pkthdr.len = m->m_len; 313 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 314 nip = mtod(m, struct ip *); 315 /* ip_v set in ip_output */ 316 nip->ip_hl = sizeof(struct ip) >> 2; 317 nip->ip_tos = 0; 318 nip->ip_len = htons(m->m_len); 319 /* ip_id set in ip_output */ 320 nip->ip_off = htons(0); 321 /* ip_ttl set in icmp_reflect */ 322 nip->ip_p = IPPROTO_ICMP; 323 nip->ip_src = oip->ip_src; 324 nip->ip_dst = oip->ip_dst; 325 icmp_reflect(m); 326 327 freeit: 328 m_freem(n); 329 } 330 331 static struct mbuf * 332 ip4_check(struct mbuf *m) 333 { 334 struct ip *iph; 335 int hlen, len; 336 337 if (m->m_len < sizeof(struct ip) && 338 (m = m_pullup(m, sizeof(struct ip))) == NULL) 339 return NULL; 340 341 iph = mtod(m, struct ip *); 342 343 if (iph->ip_v != IPVERSION) 344 goto freeit; 345 hlen = iph->ip_hl << 2; 346 if (hlen < sizeof(struct ip)) 347 goto freeit; 348 if (hlen > m->m_len) { 349 if ((m = m_pullup(m, hlen)) == NULL) 350 return NULL; 351 iph = mtod(m, struct ip *); 352 } 353 if (IN_MULTICAST(iph->ip_src.s_addr) || 354 (ntohl(iph->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 355 (ntohl(iph->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 356 in_cksum(m, hlen) != 0) 357 goto freeit; 358 359 len = ntohs(iph->ip_len); 360 if (len < hlen || m->m_pkthdr.len < len) 361 goto freeit; 362 363 return m; 364 365 freeit: 366 m_freem(m); 367 return NULL; 368 } 369 #endif /* INET */ 370 371 struct mbuf * 372 mpls_ttl_dec(struct mbuf *m) 373 { 374 union mpls_shim *mshim; 375 #ifdef INET 376 union mpls_shim top_shim, bossh; 377 #endif 378 379 if (__predict_false(m->m_len < sizeof(union mpls_shim) && 380 (m = m_pullup(m, sizeof(union mpls_shim))) == NULL)) 381 return NULL; 382 mshim = mtod(m, union mpls_shim *); 383 mshim->s_addr = ntohl(mshim->s_addr); 384 mshim->shim.ttl--; 385 386 if (mshim->shim.ttl == 0) { 387 if (!mpls_icmp_respond) { 388 m_freem(m); 389 return NULL; 390 } 391 392 #ifdef INET 393 /* 394 * Shim ttl exceeded. Send back ICMP type 11 code 0. 395 */ 396 bossh.s_addr = mshim->s_addr; 397 top_shim.s_addr = htonl(mshim->s_addr); 398 m_adj(m, sizeof(union mpls_shim)); 399 400 /* Goto BOS */ 401 while (bossh.shim.bos == 0) { 402 if (m->m_len < sizeof(union mpls_shim) && 403 (m = m_pullup(m, sizeof(union mpls_shim))) == NULL) { 404 m_freem(m); 405 return NULL; 406 } 407 bossh.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr); 408 m_adj(m, sizeof(union mpls_shim)); 409 } 410 411 if ((m = ip4_check(m)) != NULL) 412 mpls_icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 413 0, 0, &top_shim); 414 #else 415 m_freem(m); 416 #endif 417 return NULL; 418 } 419 420 mshim->s_addr = htonl(mshim->s_addr); 421 422 return m; 423 } 424
Indexes created Mon Sep 22 13:09:51 GMT 2025