mpls_ttl.c revision 1.5
1 /* $NetBSD: mpls_ttl.c,v 1.5 2015/08/24 22:21:27 pooka 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 1.5 2015/08/24 22:21:27 pooka 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 #include <net/route.h> 117 118 #include <netinet/in.h> 119 #include <netinet/in_systm.h> 120 #include <netinet/ip.h> 121 #include <netinet/ip_icmp.h> 122 #include <netinet/icmp_private.h> 123 #include <netinet/icmp_var.h> 124 125 #include <netmpls/mpls.h> 126 #include <netmpls/mpls_var.h> 127 128 #ifdef INET 129 130 /* in netinet/ip_icmp.c */ 131 extern int icmpreturndatabytes; 132 133 /* ICMP Extensions */ 134 135 #define ICMP_EXT_VERSION 2 136 #define MPLS_RETURN_DATA 128 137 #define ICMP_EXT_OFFSET 128 138 139 struct icmp_ext_cmn_hdr { 140 #if BYTE_ORDER == BIG_ENDIAN 141 unsigned char version:4; 142 unsigned char reserved1:4; 143 #else 144 unsigned char reserved1:4; 145 unsigned char version:4; 146 #endif 147 unsigned char reserved2; 148 unsigned short checksum; 149 }; 150 151 struct icmp_ext_obj_hdr { 152 u_short length; 153 u_char class_num; 154 #define MPLS_STACK_ENTRY_CLASS 1 155 u_char c_type; 156 #define MPLS_STACK_ENTRY_C_TYPE 1 157 }; 158 159 struct mpls_extension { 160 struct icmp_ext_cmn_hdr cmn_hdr; 161 struct icmp_ext_obj_hdr obj_hdr; 162 union mpls_shim ms; 163 } __packed; 164 165 static void mpls_icmp_error(struct mbuf *, int, int, n_long, int, 166 union mpls_shim *); 167 static bool ip4_check(struct mbuf *); 168 169 /* 170 * References: RFC 4884 and RFC 4950 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 */ 174 175 static void 176 mpls_icmp_error(struct mbuf *n, int type, int code, n_long dest, 177 int destmtu, union mpls_shim *shim) 178 { 179 struct ip *oip = mtod(n, struct ip *), *nip; 180 unsigned oiplen = oip->ip_hl << 2; 181 struct icmp *icp; 182 struct mbuf *m; 183 unsigned icmplen, mblen, packetlen; 184 struct mpls_extension mpls_icmp_ext; 185 186 memset(&mpls_icmp_ext, 0, sizeof(mpls_icmp_ext)); 187 mpls_icmp_ext.cmn_hdr.version = ICMP_EXT_VERSION; 188 mpls_icmp_ext.cmn_hdr.checksum = 0; 189 190 mpls_icmp_ext.obj_hdr.length = htons(sizeof(union mpls_shim) + 191 sizeof(struct icmp_ext_obj_hdr)); 192 mpls_icmp_ext.obj_hdr.class_num = MPLS_STACK_ENTRY_CLASS; 193 mpls_icmp_ext.obj_hdr.c_type = MPLS_STACK_ENTRY_C_TYPE; 194 195 mpls_icmp_ext.ms.s_addr = shim->s_addr; 196 197 #ifdef ICMPPRINTFS 198 if (icmpprintfs) 199 printf("mpls_icmp_error(%p, type:%d, code:%d)\n", oip, type, 200 code); 201 #endif 202 if (type != ICMP_REDIRECT) 203 ICMP_STATINC(ICMP_STAT_ERROR); 204 /* 205 * Don't send error if the original packet was encrypted. 206 * Don't send error if not the first fragment of message. 207 * Don't error if the old packet protocol was ICMP 208 * error message, only known informational types. 209 */ 210 if (n->m_flags & M_DECRYPTED) 211 goto freeit; 212 if (oip->ip_off &~ htons(IP_MF|IP_DF)) 213 goto freeit; 214 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 215 n->m_len >= oiplen + ICMP_MINLEN && 216 !ICMP_INFOTYPE(((struct icmp *)((char *)oip + oiplen))->icmp_type)) 217 { 218 ICMP_STATINC(ICMP_STAT_OLDICMP); 219 goto freeit; 220 } 221 /* Don't send error in response to a multicast or broadcast packet */ 222 if (n->m_flags & (M_BCAST|M_MCAST)) 223 goto freeit; 224 225 /* 226 * First, do a rate limitation check. 227 */ 228 if (icmp_ratelimit(&oip->ip_src, type, code)) 229 /* XXX stats */ 230 goto freeit; 231 232 /* 233 * Now, formulate icmp message 234 */ 235 icmplen = min(ICMP_EXT_OFFSET, ntohs(oip->ip_len)); 236 /* 237 * Defend against mbuf chains shorter than oip->ip_len - oiplen: 238 */ 239 mblen = 0; 240 for (m = n; m && (mblen < icmplen); m = m->m_next) 241 mblen += m->m_len; 242 icmplen = min(mblen, icmplen); 243 244 packetlen = sizeof(struct ip) + offsetof(struct icmp, icmp_ip) + 245 ICMP_EXT_OFFSET + sizeof(mpls_icmp_ext); 246 247 /* 248 * As we are not required to return everything we have, 249 * we return whatever we can return at ease. 250 * 251 * Note that ICMP datagrams longer than 576 octets are out of spec 252 * according to RFC1812; the limit on icmpreturndatabytes below in 253 * icmp_sysctl will keep things below that limit. 254 */ 255 256 KASSERT (packetlen <= MCLBYTES); 257 258 m = m_gethdr(M_DONTWAIT, MT_HEADER); 259 if (m && (packetlen > MHLEN)) { 260 MCLGET(m, M_DONTWAIT); 261 if ((m->m_flags & M_EXT) == 0) { 262 m_freem(m); 263 m = NULL; 264 } 265 } 266 if (m == NULL) 267 goto freeit; 268 MCLAIM(m, n->m_owner); 269 m->m_len = packetlen; 270 if ((m->m_flags & M_EXT) == 0) 271 MH_ALIGN(m, m->m_len); 272 m->m_data += sizeof(struct ip); 273 m->m_len -= sizeof(struct ip); 274 275 icp = mtod(m, struct icmp *); 276 if ((u_int)type > ICMP_MAXTYPE) 277 panic("icmp error (mpls_ttl)"); 278 ICMP_STATINC(ICMP_STAT_OUTHIST + type); 279 icp->icmp_type = type; 280 if (type == ICMP_REDIRECT) 281 icp->icmp_gwaddr.s_addr = dest; 282 else { 283 icp->icmp_void = 0; 284 /* 285 * The following assignments assume an overlay with the 286 * zeroed icmp_void field. 287 */ 288 if (type == ICMP_PARAMPROB) { 289 icp->icmp_pptr = code; 290 code = 0; 291 } else if (type == ICMP_UNREACH && 292 code == ICMP_UNREACH_NEEDFRAG && destmtu) 293 icp->icmp_nextmtu = htons(destmtu); 294 } 295 296 icp->icmp_code = code; 297 298 memset(&icp->icmp_ip, 0, ICMP_EXT_OFFSET); 299 m_copydata(n, 0, icmplen, (char *)&icp->icmp_ip); 300 301 /* Append the extension structure */ 302 memcpy(((char*)&icp->icmp_ip) + ICMP_EXT_OFFSET, 303 &mpls_icmp_ext, sizeof(mpls_icmp_ext)); 304 305 /* 306 * Now, copy old ip header (without options) 307 * in front of icmp message. 308 */ 309 if ((m->m_flags & M_EXT) == 0 && 310 m->m_data - sizeof(struct ip) < m->m_pktdat) 311 panic("icmp len"); 312 m->m_data -= sizeof(struct ip); 313 m->m_len += sizeof(struct ip); 314 m->m_pkthdr.len = m->m_len; 315 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 316 nip = mtod(m, struct ip *); 317 /* ip_v set in ip_output */ 318 nip->ip_hl = sizeof(struct ip) >> 2; 319 nip->ip_tos = 0; 320 nip->ip_len = htons(m->m_len); 321 /* ip_id set in ip_output */ 322 nip->ip_off = htons(0); 323 /* ip_ttl set in icmp_reflect */ 324 nip->ip_p = IPPROTO_ICMP; 325 nip->ip_src = oip->ip_src; 326 nip->ip_dst = oip->ip_dst; 327 icmp_reflect(m); 328 329 freeit: 330 m_freem(n); 331 332 } 333 334 static bool 335 ip4_check(struct mbuf *m) 336 { 337 struct ip *iph; 338 int hlen, len; 339 340 if (m->m_len < sizeof(struct ip) && 341 (m = m_pullup(m, sizeof(struct ip))) == NULL) 342 return false; 343 344 iph = mtod(m, struct ip *); 345 346 if (iph->ip_v != IPVERSION) 347 goto freeit; 348 hlen = iph->ip_hl << 2; 349 if (hlen < sizeof(struct ip)) 350 goto freeit; 351 if (hlen > m->m_len) { 352 if ((m = m_pullup(m, hlen)) == NULL) 353 return false; 354 iph = mtod(m, struct ip *); 355 } 356 if (IN_MULTICAST(iph->ip_src.s_addr) || 357 (ntohl(iph->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 358 (ntohl(iph->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 359 in_cksum(m, hlen) != 0) 360 goto freeit; 361 362 len = ntohs(iph->ip_len); 363 if (len < hlen || m->m_pkthdr.len < len) 364 goto freeit; 365 366 return true; 367 freeit: 368 m_freem(m); 369 return false; 370 371 } 372 373 #endif /* INET */ 374 375 struct mbuf * 376 mpls_ttl_dec(struct mbuf *m) 377 { 378 union mpls_shim *mshim; 379 #ifdef INET 380 union mpls_shim top_shim, bossh; 381 #endif 382 383 if (__predict_false(m->m_len < sizeof(union mpls_shim) && 384 (m = m_pullup(m, sizeof(union mpls_shim))) == NULL)) 385 return NULL; 386 mshim = mtod(m, union mpls_shim *); 387 mshim->s_addr = ntohl(mshim->s_addr); 388 mshim->shim.ttl--; 389 390 if (mshim->shim.ttl == 0) { 391 if (!mpls_icmp_respond) { 392 m_freem(m); 393 return NULL; 394 } 395 396 #ifdef INET 397 /* 398 * shim ttl exceeded 399 * send back ICMP type 11 code 0 400 */ 401 bossh.s_addr = mshim->s_addr; 402 top_shim.s_addr = htonl(mshim->s_addr); 403 m_adj(m, sizeof(union mpls_shim)); 404 405 /* Goto BOS */ 406 while(bossh.shim.bos == 0) { 407 if (m->m_len < sizeof(union mpls_shim) && 408 (m = m_pullup(m, sizeof(union mpls_shim))) == NULL) { 409 m_freem(m); 410 return NULL; 411 } 412 bossh.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr); 413 m_adj(m, sizeof(union mpls_shim)); 414 } 415 416 if (ip4_check(m) == true) 417 mpls_icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 418 0, 0, &top_shim); 419 #else 420 m_freem(m); 421 #endif 422 return NULL; 423 } 424 425 mshim->s_addr = htonl(mshim->s_addr); 426 427 return m; 428 } 429
Indexes created Mon Sep 22 10:09:38 GMT 2025