1 /* $NetBSD: mpls_ttl.c,v 1.9 2017/12/08 17:49:54 maxv 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@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 1.9 2017/12/08 17:49:54 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 */ 133 134 #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 * References: RFC 4884 and RFC 4950 170 * This should be in sync with icmp_error() in sys/netinet/ip_icmp.c 171 * XXX: is called only for ICMP_TIMXCEED_INTRANS but code is too general 172 */ 173 174 static void 175 mpls_icmp_error(struct mbuf *n, int type, int code, n_long dest, 176 int destmtu, union mpls_shim *shim) 177 { 178 struct ip *oip = mtod(n, struct ip *), *nip; 179 unsigned oiplen = oip->ip_hl << 2; 180 struct icmp *icp; 181 struct mbuf *m; 182 unsigned icmplen, mblen, packetlen; 183 struct mpls_extension mpls_icmp_ext; 184 185 memset(&mpls_icmp_ext, 0, sizeof(mpls_icmp_ext)); 186 mpls_icmp_ext.cmn_hdr.version = ICMP_EXT_VERSION; 187 mpls_icmp_ext.cmn_hdr.checksum = 0; 188 189 mpls_icmp_ext.obj_hdr.length = htons(sizeof(union mpls_shim) + 190 sizeof(struct icmp_ext_obj_hdr)); 191 mpls_icmp_ext.obj_hdr.class_num = MPLS_STACK_ENTRY_CLASS; 192 mpls_icmp_ext.obj_hdr.c_type = MPLS_STACK_ENTRY_C_TYPE; 193 194 mpls_icmp_ext.ms.s_addr = shim->s_addr; 195 196 #ifdef ICMPPRINTFS 197 if (icmpprintfs) 198 printf("mpls_icmp_error(%p, type:%d, code:%d)\n", oip, type, 199 code); 200 #endif 201 if (type != ICMP_REDIRECT) 202 ICMP_STATINC(ICMP_STAT_ERROR); 203 /* 204 * Don't send error if the original packet was encrypted. 205 * Don't send error if not the first fragment of message. 206 * Don't error if the old packet protocol was ICMP 207 * error message, only known informational types. 208 */ 209 if (n->m_flags & M_DECRYPTED) 210 goto freeit; 211 if (oip->ip_off &~ htons(IP_MF|IP_DF)) 212 goto freeit; 213 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 214 n->m_len >= oiplen + ICMP_MINLEN && 215 !ICMP_INFOTYPE(((struct icmp *)((char *)oip + oiplen))->icmp_type)) 216 { 217 ICMP_STATINC(ICMP_STAT_OLDICMP); 218 goto freeit; 219 } 220 /* Don't send error in response to a multicast or broadcast packet */ 221 if (n->m_flags & (M_BCAST|M_MCAST)) 222 goto freeit; 223 224 /* 225 * First, do a rate limitation check. 226 */ 227 if (icmp_ratelimit(&oip->ip_src, type, code)) 228 /* XXX stats */ 229 goto freeit; 230 231 /* 232 * Now, formulate icmp message 233 */ 234 icmplen = min(ICMP_EXT_OFFSET, ntohs(oip->ip_len)); 235 /* 236 * Defend against mbuf chains shorter than oip->ip_len - oiplen: 237 */ 238 mblen = 0; 239 for (m = n; m && (mblen < icmplen); m = m->m_next) 240 mblen += m->m_len; 241 icmplen = min(mblen, icmplen); 242 243 packetlen = sizeof(struct ip) + offsetof(struct icmp, icmp_ip) + 244 ICMP_EXT_OFFSET + sizeof(mpls_icmp_ext); 245 246 /* 247 * As we are not required to return everything we have, 248 * we return whatever we can return at ease. 249 * 250 * Note that ICMP datagrams longer than 576 octets are out of spec 251 * according to RFC1812; the limit on icmpreturndatabytes below in 252 * icmp_sysctl will keep things below that limit. 253 */ 254 255 KASSERT (packetlen <= MCLBYTES); 256 257 m = m_gethdr(M_DONTWAIT, MT_HEADER); 258 if (m && (packetlen > MHLEN)) { 259 MCLGET(m, M_DONTWAIT); 260 if ((m->m_flags & M_EXT) == 0) { 261 m_freem(m); 262 m = NULL; 263 } 264 } 265 if (m == NULL) 266 goto freeit; 267 MCLAIM(m, n->m_owner); 268 m->m_len = packetlen; 269 if ((m->m_flags & M_EXT) == 0) 270 MH_ALIGN(m, m->m_len); 271 m->m_data += sizeof(struct ip); 272 m->m_len -= sizeof(struct ip); 273 274 icp = mtod(m, struct icmp *); 275 if ((u_int)type > ICMP_MAXTYPE) 276 panic("icmp error (mpls_ttl)"); 277 ICMP_STATINC(ICMP_STAT_OUTHIST + type); 278 icp->icmp_type = type; 279 if (type == ICMP_REDIRECT) 280 icp->icmp_gwaddr.s_addr = dest; 281 else { 282 icp->icmp_void = 0; 283 /* 284 * The following assignments assume an overlay with the 285 * zeroed icmp_void field. 286 */ 287 if (type == ICMP_PARAMPROB) { 288 icp->icmp_pptr = code; 289 code = 0; 290 } else if (type == ICMP_UNREACH && 291 code == ICMP_UNREACH_NEEDFRAG && destmtu) 292 icp->icmp_nextmtu = htons(destmtu); 293 } 294 295 icp->icmp_code = code; 296 297 memset(&icp->icmp_ip, 0, ICMP_EXT_OFFSET); 298 m_copydata(n, 0, icmplen, (char *)&icp->icmp_ip); 299 300 /* Append the extension structure */ 301 memcpy(((char*)&icp->icmp_ip) + ICMP_EXT_OFFSET, 302 &mpls_icmp_ext, sizeof(mpls_icmp_ext)); 303 304 /* 305 * Now, copy old ip header (without options) 306 * in front of icmp message. 307 */ 308 if ((m->m_flags & M_EXT) == 0 && 309 m->m_data - sizeof(struct ip) < m->m_pktdat) 310 panic("icmp len"); 311 m->m_data -= sizeof(struct ip); 312 m->m_len += sizeof(struct ip); 313 m->m_pkthdr.len = m->m_len; 314 m_copy_rcvif(m, n); 315 nip = mtod(m, struct ip *); 316 /* ip_v set in ip_output */ 317 nip->ip_hl = sizeof(struct ip) >> 2; 318 nip->ip_tos = 0; 319 nip->ip_len = htons(m->m_len); 320 /* ip_id set in ip_output */ 321 nip->ip_off = htons(0); 322 /* ip_ttl set in icmp_reflect */ 323 nip->ip_p = IPPROTO_ICMP; 324 nip->ip_src = oip->ip_src; 325 nip->ip_dst = oip->ip_dst; 326 icmp_reflect(m); 327 328 freeit: 329 m_freem(n); 330 } 331 332 static struct mbuf * 333 ip4_check(struct mbuf *m) 334 { 335 struct ip *iph; 336 int hlen, len; 337 338 if (m->m_len < sizeof(struct ip) && 339 (m = m_pullup(m, sizeof(struct ip))) == NULL) 340 return NULL; 341 342 iph = mtod(m, struct ip *); 343 344 if (iph->ip_v != IPVERSION) 345 goto freeit; 346 hlen = iph->ip_hl << 2; 347 if (hlen < sizeof(struct ip)) 348 goto freeit; 349 if (hlen > m->m_len) { 350 if ((m = m_pullup(m, hlen)) == NULL) 351 return NULL; 352 iph = mtod(m, struct ip *); 353 } 354 if (IN_MULTICAST(iph->ip_src.s_addr) || 355 (ntohl(iph->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 356 (ntohl(iph->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 357 in_cksum(m, hlen) != 0) 358 goto freeit; 359 360 len = ntohs(iph->ip_len); 361 if (len < hlen || m->m_pkthdr.len < len) 362 goto freeit; 363 364 return m; 365 366 freeit: 367 m_freem(m); 368 return NULL; 369 } 370 #endif /* INET */ 371 372 struct mbuf * 373 mpls_ttl_dec(struct mbuf *m) 374 { 375 union mpls_shim *mshim; 376 #ifdef INET 377 union mpls_shim top_shim, bossh; 378 #endif 379 380 if (__predict_false(m->m_len < sizeof(union mpls_shim) && 381 (m = m_pullup(m, sizeof(union mpls_shim))) == NULL)) 382 return NULL; 383 mshim = mtod(m, union mpls_shim *); 384 mshim->s_addr = ntohl(mshim->s_addr); 385 mshim->shim.ttl--; 386 387 if (mshim->shim.ttl == 0) { 388 if (!mpls_icmp_respond) { 389 m_freem(m); 390 return NULL; 391 } 392 393 #ifdef INET 394 /* 395 * Shim ttl exceeded. Send back ICMP type 11 code 0. 396 */ 397 bossh.s_addr = mshim->s_addr; 398 top_shim.s_addr = htonl(mshim->s_addr); 399 m_adj(m, sizeof(union mpls_shim)); 400 401 /* Goto BOS */ 402 while (bossh.shim.bos == 0) { 403 if (m->m_len < sizeof(union mpls_shim) && 404 (m = m_pullup(m, sizeof(union mpls_shim))) == NULL) { 405 m_freem(m); 406 return NULL; 407 } 408 bossh.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr); 409 m_adj(m, sizeof(union mpls_shim)); 410 } 411 412 if ((m = ip4_check(m)) != NULL) 413 mpls_icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 414 0, 0, &top_shim); 415 #else 416 m_freem(m); 417 #endif 418 return NULL; 419 } 420 421 mshim->s_addr = htonl(mshim->s_addr); 422 423 return m; 424 } 425