1 /* $NetBSD: ip_icmp.c,v 1.114 2007/11/09 23:42:56 dyoung 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) 1998, 2000 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 * 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. All advertising materials mentioning features or use of this software 52 * must display the following acknowledgement: 53 * This product includes software developed by the NetBSD 54 * Foundation, Inc. and its contributors. 55 * 4. Neither the name of The NetBSD Foundation nor the names of its 56 * contributors may be used to endorse or promote products derived 57 * from this software without specific prior written permission. 58 * 59 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 60 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 61 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 62 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 63 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 64 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 65 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 66 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 67 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 68 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 69 * POSSIBILITY OF SUCH DAMAGE. 70 */ 71 72 /* 73 * Copyright (c) 1982, 1986, 1988, 1993 74 * The Regents of the University of California. All rights reserved. 75 * 76 * Redistribution and use in source and binary forms, with or without 77 * modification, are permitted provided that the following conditions 78 * are met: 79 * 1. Redistributions of source code must retain the above copyright 80 * notice, this list of conditions and the following disclaimer. 81 * 2. Redistributions in binary form must reproduce the above copyright 82 * notice, this list of conditions and the following disclaimer in the 83 * documentation and/or other materials provided with the distribution. 84 * 3. Neither the name of the University nor the names of its contributors 85 * may be used to endorse or promote products derived from this software 86 * without specific prior written permission. 87 * 88 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 89 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 90 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 91 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 92 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 93 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 94 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 95 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 96 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 97 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 98 * SUCH DAMAGE. 99 * 100 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 101 */ 102 103 #include <sys/cdefs.h> 104 __KERNEL_RCSID(0, "$NetBSD: ip_icmp.c,v 1.114 2007/11/09 23:42:56 dyoung Exp $"); 105 106 #include "opt_ipsec.h" 107 108 #include <sys/param.h> 109 #include <sys/systm.h> 110 #include <sys/malloc.h> 111 #include <sys/mbuf.h> 112 #include <sys/protosw.h> 113 #include <sys/socket.h> 114 #include <sys/time.h> 115 #include <sys/kernel.h> 116 #include <sys/syslog.h> 117 #include <sys/sysctl.h> 118 119 #include <net/if.h> 120 #include <net/route.h> 121 122 #include <netinet/in.h> 123 #include <netinet/in_systm.h> 124 #include <netinet/in_var.h> 125 #include <netinet/ip.h> 126 #include <netinet/ip_icmp.h> 127 #include <netinet/ip_var.h> 128 #include <netinet/in_pcb.h> 129 #include <netinet/in_proto.h> 130 #include <netinet/icmp_var.h> 131 132 #ifdef IPSEC 133 #include <netinet6/ipsec.h> 134 #include <netkey/key.h> 135 #endif 136 137 #ifdef FAST_IPSEC 138 #include <netipsec/ipsec.h> 139 #include <netipsec/key.h> 140 #endif /* FAST_IPSEC*/ 141 142 #include <machine/stdarg.h> 143 144 /* 145 * ICMP routines: error generation, receive packet processing, and 146 * routines to turnaround packets back to the originator, and 147 * host table maintenance routines. 148 */ 149 150 int icmpmaskrepl = 0; 151 #ifdef ICMPPRINTFS 152 int icmpprintfs = 0; 153 #endif 154 int icmpreturndatabytes = 8; 155 156 struct icmpstat icmpstat; 157 158 /* 159 * List of callbacks to notify when Path MTU changes are made. 160 */ 161 struct icmp_mtudisc_callback { 162 LIST_ENTRY(icmp_mtudisc_callback) mc_list; 163 void (*mc_func)(struct in_addr); 164 }; 165 166 LIST_HEAD(, icmp_mtudisc_callback) icmp_mtudisc_callbacks = 167 LIST_HEAD_INITIALIZER(&icmp_mtudisc_callbacks); 168 169 #if 0 170 static u_int ip_next_mtu(u_int, int); 171 #else 172 /*static*/ u_int ip_next_mtu(u_int, int); 173 #endif 174 175 extern int icmperrppslim; 176 static int icmperrpps_count = 0; 177 static struct timeval icmperrppslim_last; 178 static int icmp_rediraccept = 1; 179 static int icmp_redirtimeout = 600; 180 static struct rttimer_queue *icmp_redirect_timeout_q = NULL; 181 182 static void icmp_mtudisc_timeout(struct rtentry *, struct rttimer *); 183 static void icmp_redirect_timeout(struct rtentry *, struct rttimer *); 184 185 static int icmp_ratelimit(const struct in_addr *, const int, const int); 186 187 188 void 189 icmp_init(void) 190 { 191 /* 192 * This is only useful if the user initializes redirtimeout to 193 * something other than zero. 194 */ 195 if (icmp_redirtimeout != 0) { 196 icmp_redirect_timeout_q = 197 rt_timer_queue_create(icmp_redirtimeout); 198 } 199 } 200 201 /* 202 * Register a Path MTU Discovery callback. 203 */ 204 void 205 icmp_mtudisc_callback_register(void (*func)(struct in_addr)) 206 { 207 struct icmp_mtudisc_callback *mc; 208 209 for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL; 210 mc = LIST_NEXT(mc, mc_list)) { 211 if (mc->mc_func == func) 212 return; 213 } 214 215 mc = malloc(sizeof(*mc), M_PCB, M_NOWAIT); 216 if (mc == NULL) 217 panic("icmp_mtudisc_callback_register"); 218 219 mc->mc_func = func; 220 LIST_INSERT_HEAD(&icmp_mtudisc_callbacks, mc, mc_list); 221 } 222 223 /* 224 * Generate an error packet of type error 225 * in response to bad packet ip. 226 */ 227 void 228 icmp_error(struct mbuf *n, int type, int code, n_long dest, 229 int destmtu) 230 { 231 struct ip *oip = mtod(n, struct ip *), *nip; 232 unsigned oiplen = oip->ip_hl << 2; 233 struct icmp *icp; 234 struct mbuf *m; 235 struct m_tag *mtag; 236 unsigned icmplen, mblen; 237 238 #ifdef ICMPPRINTFS 239 if (icmpprintfs) 240 printf("icmp_error(%p, type:%d, code:%d)\n", oip, type, code); 241 #endif 242 if (type != ICMP_REDIRECT) 243 icmpstat.icps_error++; 244 /* 245 * Don't send error if the original packet was encrypted. 246 * Don't send error if not the first fragment of message. 247 * Don't error if the old packet protocol was ICMP 248 * error message, only known informational types. 249 */ 250 if (n->m_flags & M_DECRYPTED) 251 goto freeit; 252 if (oip->ip_off &~ htons(IP_MF|IP_DF)) 253 goto freeit; 254 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 255 n->m_len >= oiplen + ICMP_MINLEN && 256 !ICMP_INFOTYPE(((struct icmp *)((char *)oip + oiplen))->icmp_type)) { 257 icmpstat.icps_oldicmp++; 258 goto freeit; 259 } 260 /* Don't send error in response to a multicast or broadcast packet */ 261 if (n->m_flags & (M_BCAST|M_MCAST)) 262 goto freeit; 263 264 /* 265 * First, do a rate limitation check. 266 */ 267 if (icmp_ratelimit(&oip->ip_src, type, code)) { 268 /* XXX stat */ 269 goto freeit; 270 } 271 272 /* 273 * Now, formulate icmp message 274 */ 275 icmplen = oiplen + min(icmpreturndatabytes, 276 ntohs(oip->ip_len) - oiplen); 277 /* 278 * Defend against mbuf chains shorter than oip->ip_len - oiplen: 279 */ 280 mblen = 0; 281 for (m = n; m && (mblen < icmplen); m = m->m_next) 282 mblen += m->m_len; 283 icmplen = min(mblen, icmplen); 284 285 /* 286 * As we are not required to return everything we have, 287 * we return whatever we can return at ease. 288 * 289 * Note that ICMP datagrams longer than 576 octets are out of spec 290 * according to RFC1812; the limit on icmpreturndatabytes below in 291 * icmp_sysctl will keep things below that limit. 292 */ 293 294 KASSERT(ICMP_MINLEN <= MCLBYTES); 295 296 if (icmplen + ICMP_MINLEN > MCLBYTES) 297 icmplen = MCLBYTES - ICMP_MINLEN; 298 299 m = m_gethdr(M_DONTWAIT, MT_HEADER); 300 if (m && (icmplen + ICMP_MINLEN > MHLEN)) { 301 MCLGET(m, M_DONTWAIT); 302 if ((m->m_flags & M_EXT) == 0) { 303 m_freem(m); 304 m = NULL; 305 } 306 } 307 if (m == NULL) 308 goto freeit; 309 MCLAIM(m, n->m_owner); 310 m->m_len = icmplen + ICMP_MINLEN; 311 if ((m->m_flags & M_EXT) == 0) 312 MH_ALIGN(m, m->m_len); 313 icp = mtod(m, struct icmp *); 314 if ((u_int)type > ICMP_MAXTYPE) 315 panic("icmp_error"); 316 icmpstat.icps_outhist[type]++; 317 icp->icmp_type = type; 318 if (type == ICMP_REDIRECT) 319 icp->icmp_gwaddr.s_addr = dest; 320 else { 321 icp->icmp_void = 0; 322 /* 323 * The following assignments assume an overlay with the 324 * zeroed icmp_void field. 325 */ 326 if (type == ICMP_PARAMPROB) { 327 icp->icmp_pptr = code; 328 code = 0; 329 } else if (type == ICMP_UNREACH && 330 code == ICMP_UNREACH_NEEDFRAG && destmtu) 331 icp->icmp_nextmtu = htons(destmtu); 332 } 333 334 icp->icmp_code = code; 335 m_copydata(n, 0, icmplen, (void *)&icp->icmp_ip); 336 337 /* 338 * Now, copy old ip header (without options) 339 * in front of icmp message. 340 */ 341 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 342 panic("icmp len"); 343 m->m_data -= sizeof(struct ip); 344 m->m_len += sizeof(struct ip); 345 m->m_pkthdr.len = m->m_len; 346 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 347 nip = mtod(m, struct ip *); 348 /* ip_v set in ip_output */ 349 nip->ip_hl = sizeof(struct ip) >> 2; 350 nip->ip_tos = 0; 351 nip->ip_len = htons(m->m_len); 352 /* ip_id set in ip_output */ 353 nip->ip_off = htons(0); 354 /* ip_ttl set in icmp_reflect */ 355 nip->ip_p = IPPROTO_ICMP; 356 nip->ip_src = oip->ip_src; 357 nip->ip_dst = oip->ip_dst; 358 /* move PF_GENERATED m_tag to new packet, if it exists */ 359 mtag = m_tag_find(n, PACKET_TAG_PF_GENERATED, NULL); 360 if (mtag != NULL) { 361 m_tag_unlink(n, mtag); 362 m_tag_prepend(m, mtag); 363 } 364 icmp_reflect(m); 365 366 freeit: 367 m_freem(n); 368 } 369 370 struct sockaddr_in icmpsrc = { 371 .sin_len = sizeof (struct sockaddr_in), 372 .sin_family = AF_INET, 373 }; 374 static struct sockaddr_in icmpdst = { 375 .sin_len = sizeof (struct sockaddr_in), 376 .sin_family = AF_INET, 377 }; 378 static struct sockaddr_in icmpgw = { 379 .sin_len = sizeof (struct sockaddr_in), 380 .sin_family = AF_INET, 381 }; 382 struct sockaddr_in icmpmask = { 383 .sin_len = 8, 384 .sin_family = 0, 385 }; 386 387 /* 388 * Process a received ICMP message. 389 */ 390 void 391 icmp_input(struct mbuf *m, ...) 392 { 393 int proto; 394 struct icmp *icp; 395 struct ip *ip = mtod(m, struct ip *); 396 int icmplen; 397 int i; 398 struct in_ifaddr *ia; 399 void *(*ctlfunc)(int, const struct sockaddr *, void *); 400 int code; 401 int hlen; 402 va_list ap; 403 struct rtentry *rt; 404 405 va_start(ap, m); 406 hlen = va_arg(ap, int); 407 proto = va_arg(ap, int); 408 va_end(ap); 409 410 /* 411 * Locate icmp structure in mbuf, and check 412 * that not corrupted and of at least minimum length. 413 */ 414 icmplen = ntohs(ip->ip_len) - hlen; 415 #ifdef ICMPPRINTFS 416 if (icmpprintfs) { 417 printf("icmp_input from `%s' to ", inet_ntoa(ip->ip_src)); 418 printf("`%s', len %d\n", inet_ntoa(ip->ip_dst), icmplen); 419 } 420 #endif 421 if (icmplen < ICMP_MINLEN) { 422 icmpstat.icps_tooshort++; 423 goto freeit; 424 } 425 i = hlen + min(icmplen, ICMP_ADVLENMIN); 426 if ((m->m_len < i || M_READONLY(m)) && (m = m_pullup(m, i)) == 0) { 427 icmpstat.icps_tooshort++; 428 return; 429 } 430 ip = mtod(m, struct ip *); 431 m->m_len -= hlen; 432 m->m_data += hlen; 433 icp = mtod(m, struct icmp *); 434 /* Don't need to assert alignment, here. */ 435 if (in_cksum(m, icmplen)) { 436 icmpstat.icps_checksum++; 437 goto freeit; 438 } 439 m->m_len += hlen; 440 m->m_data -= hlen; 441 442 #ifdef ICMPPRINTFS 443 /* 444 * Message type specific processing. 445 */ 446 if (icmpprintfs) 447 printf("icmp_input(type:%d, code:%d)\n", icp->icmp_type, 448 icp->icmp_code); 449 #endif 450 if (icp->icmp_type > ICMP_MAXTYPE) 451 goto raw; 452 icmpstat.icps_inhist[icp->icmp_type]++; 453 code = icp->icmp_code; 454 switch (icp->icmp_type) { 455 456 case ICMP_UNREACH: 457 switch (code) { 458 case ICMP_UNREACH_NET: 459 code = PRC_UNREACH_NET; 460 break; 461 462 case ICMP_UNREACH_HOST: 463 code = PRC_UNREACH_HOST; 464 break; 465 466 case ICMP_UNREACH_PROTOCOL: 467 code = PRC_UNREACH_PROTOCOL; 468 break; 469 470 case ICMP_UNREACH_PORT: 471 code = PRC_UNREACH_PORT; 472 break; 473 474 case ICMP_UNREACH_SRCFAIL: 475 code = PRC_UNREACH_SRCFAIL; 476 break; 477 478 case ICMP_UNREACH_NEEDFRAG: 479 code = PRC_MSGSIZE; 480 break; 481 482 case ICMP_UNREACH_NET_UNKNOWN: 483 case ICMP_UNREACH_NET_PROHIB: 484 case ICMP_UNREACH_TOSNET: 485 code = PRC_UNREACH_NET; 486 break; 487 488 case ICMP_UNREACH_HOST_UNKNOWN: 489 case ICMP_UNREACH_ISOLATED: 490 case ICMP_UNREACH_HOST_PROHIB: 491 case ICMP_UNREACH_TOSHOST: 492 code = PRC_UNREACH_HOST; 493 break; 494 495 default: 496 goto badcode; 497 } 498 goto deliver; 499 500 case ICMP_TIMXCEED: 501 if (code > 1) 502 goto badcode; 503 code += PRC_TIMXCEED_INTRANS; 504 goto deliver; 505 506 case ICMP_PARAMPROB: 507 if (code > 1) 508 goto badcode; 509 code = PRC_PARAMPROB; 510 goto deliver; 511 512 case ICMP_SOURCEQUENCH: 513 if (code) 514 goto badcode; 515 code = PRC_QUENCH; 516 goto deliver; 517 518 deliver: 519 /* 520 * Problem with datagram; advise higher level routines. 521 */ 522 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 523 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 524 icmpstat.icps_badlen++; 525 goto freeit; 526 } 527 if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr)) 528 goto badcode; 529 #ifdef ICMPPRINTFS 530 if (icmpprintfs) 531 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 532 #endif 533 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 534 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 535 if (ctlfunc) 536 (void) (*ctlfunc)(code, sintosa(&icmpsrc), 537 &icp->icmp_ip); 538 break; 539 540 badcode: 541 icmpstat.icps_badcode++; 542 break; 543 544 case ICMP_ECHO: 545 icp->icmp_type = ICMP_ECHOREPLY; 546 goto reflect; 547 548 case ICMP_TSTAMP: 549 if (icmplen < ICMP_TSLEN) { 550 icmpstat.icps_badlen++; 551 break; 552 } 553 icp->icmp_type = ICMP_TSTAMPREPLY; 554 icp->icmp_rtime = iptime(); 555 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 556 goto reflect; 557 558 case ICMP_MASKREQ: 559 if (icmpmaskrepl == 0) 560 break; 561 /* 562 * We are not able to respond with all ones broadcast 563 * unless we receive it over a point-to-point interface. 564 */ 565 if (icmplen < ICMP_MASKLEN) { 566 icmpstat.icps_badlen++; 567 break; 568 } 569 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 570 in_nullhost(ip->ip_dst)) 571 icmpdst.sin_addr = ip->ip_src; 572 else 573 icmpdst.sin_addr = ip->ip_dst; 574 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 575 m->m_pkthdr.rcvif)); 576 if (ia == 0) 577 break; 578 icp->icmp_type = ICMP_MASKREPLY; 579 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 580 if (in_nullhost(ip->ip_src)) { 581 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 582 ip->ip_src = ia->ia_broadaddr.sin_addr; 583 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 584 ip->ip_src = ia->ia_dstaddr.sin_addr; 585 } 586 reflect: 587 icmpstat.icps_reflect++; 588 icmpstat.icps_outhist[icp->icmp_type]++; 589 icmp_reflect(m); 590 return; 591 592 case ICMP_REDIRECT: 593 if (code > 3) 594 goto badcode; 595 if (icmp_rediraccept == 0) 596 goto freeit; 597 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 598 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 599 icmpstat.icps_badlen++; 600 break; 601 } 602 /* 603 * Short circuit routing redirects to force 604 * immediate change in the kernel's routing 605 * tables. The message is also handed to anyone 606 * listening on a raw socket (e.g. the routing 607 * daemon for use in updating its tables). 608 */ 609 icmpgw.sin_addr = ip->ip_src; 610 icmpdst.sin_addr = icp->icmp_gwaddr; 611 #ifdef ICMPPRINTFS 612 if (icmpprintfs) { 613 printf("redirect dst `%s' to `%s'\n", 614 inet_ntoa(icp->icmp_ip.ip_dst), 615 inet_ntoa(icp->icmp_gwaddr)); 616 } 617 #endif 618 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 619 rt = NULL; 620 rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst), 621 NULL, RTF_GATEWAY | RTF_HOST, sintosa(&icmpgw), &rt); 622 if (rt != NULL && icmp_redirtimeout != 0) { 623 i = rt_timer_add(rt, icmp_redirect_timeout, 624 icmp_redirect_timeout_q); 625 if (i) 626 log(LOG_ERR, "ICMP: redirect failed to " 627 "register timeout for route to %x, " 628 "code %d\n", 629 icp->icmp_ip.ip_dst.s_addr, i); 630 } 631 if (rt != NULL) 632 rtfree(rt); 633 634 pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc)); 635 #if defined(IPSEC) || defined(FAST_IPSEC) 636 key_sa_routechange((struct sockaddr *)&icmpsrc); 637 #endif 638 break; 639 640 /* 641 * No kernel processing for the following; 642 * just fall through to send to raw listener. 643 */ 644 case ICMP_ECHOREPLY: 645 case ICMP_ROUTERADVERT: 646 case ICMP_ROUTERSOLICIT: 647 case ICMP_TSTAMPREPLY: 648 case ICMP_IREQREPLY: 649 case ICMP_MASKREPLY: 650 default: 651 break; 652 } 653 654 raw: 655 rip_input(m, hlen, proto); 656 return; 657 658 freeit: 659 m_freem(m); 660 return; 661 } 662 663 /* 664 * Reflect the ip packet back to the source 665 */ 666 void 667 icmp_reflect(struct mbuf *m) 668 { 669 struct ip *ip = mtod(m, struct ip *); 670 struct in_ifaddr *ia; 671 struct ifaddr *ifa; 672 struct sockaddr_in *sin = 0; 673 struct in_addr t; 674 struct mbuf *opts = 0; 675 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 676 677 if (!in_canforward(ip->ip_src) && 678 ((ip->ip_src.s_addr & IN_CLASSA_NET) != 679 htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 680 m_freem(m); /* Bad return address */ 681 goto done; /* ip_output() will check for broadcast */ 682 } 683 t = ip->ip_dst; 684 ip->ip_dst = ip->ip_src; 685 /* 686 * If the incoming packet was addressed directly to us, use 687 * dst as the src for the reply. Otherwise (broadcast or 688 * anonymous), use an address which corresponds to the 689 * incoming interface, with a preference for the address which 690 * corresponds to the route to the destination of the ICMP. 691 */ 692 693 /* Look for packet addressed to us */ 694 INADDR_TO_IA(t, ia); 695 696 /* look for packet sent to broadcast address */ 697 if (ia == NULL && m->m_pkthdr.rcvif && 698 (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 699 IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) { 700 if (ifa->ifa_addr->sa_family != AF_INET) 701 continue; 702 if (in_hosteq(t,ifatoia(ifa)->ia_broadaddr.sin_addr)) { 703 ia = ifatoia(ifa); 704 break; 705 } 706 } 707 } 708 709 if (ia) 710 sin = &ia->ia_addr; 711 712 icmpdst.sin_addr = t; 713 714 /* 715 * if the packet is addressed somewhere else, compute the 716 * source address for packets routed back to the source, and 717 * use that, if it's an address on the interface which 718 * received the packet 719 */ 720 if (sin == NULL && m->m_pkthdr.rcvif) { 721 struct sockaddr_in sin_dst; 722 struct route icmproute; 723 int errornum; 724 725 sockaddr_in_init(&sin_dst, &ip->ip_dst, 0); 726 memset(&icmproute, 0, sizeof(icmproute)); 727 errornum = 0; 728 sin = in_selectsrc(&sin_dst, &icmproute, 0, NULL, &errornum); 729 /* errornum is never used */ 730 rtcache_free(&icmproute); 731 /* check to make sure sin is a source address on rcvif */ 732 if (sin) { 733 t = sin->sin_addr; 734 sin = NULL; 735 INADDR_TO_IA(t, ia); 736 while (ia) { 737 if (ia->ia_ifp == m->m_pkthdr.rcvif) { 738 sin = &ia->ia_addr; 739 break; 740 } 741 NEXT_IA_WITH_SAME_ADDR(ia); 742 } 743 } 744 } 745 746 /* 747 * if it was not addressed to us, but the route doesn't go out 748 * the source interface, pick an address on the source 749 * interface. This can happen when routing is asymmetric, or 750 * when the incoming packet was encapsulated 751 */ 752 if (sin == NULL && m->m_pkthdr.rcvif) { 753 IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) { 754 if (ifa->ifa_addr->sa_family != AF_INET) 755 continue; 756 sin = &(ifatoia(ifa)->ia_addr); 757 break; 758 } 759 } 760 761 /* 762 * The following happens if the packet was not addressed to us, 763 * and was received on an interface with no IP address: 764 * We find the first AF_INET address on the first non-loopback 765 * interface. 766 */ 767 if (sin == NULL) 768 TAILQ_FOREACH(ia, &in_ifaddrhead, ia_list) { 769 if (ia->ia_ifp->if_flags & IFF_LOOPBACK) 770 continue; 771 sin = &ia->ia_addr; 772 break; 773 } 774 775 /* 776 * If we still didn't find an address, punt. We could have an 777 * interface up (and receiving packets) with no address. 778 */ 779 if (sin == NULL) { 780 m_freem(m); 781 goto done; 782 } 783 784 ip->ip_src = sin->sin_addr; 785 ip->ip_ttl = MAXTTL; 786 787 if (optlen > 0) { 788 u_char *cp; 789 int opt, cnt; 790 u_int len; 791 792 /* 793 * Retrieve any source routing from the incoming packet; 794 * add on any record-route or timestamp options. 795 */ 796 cp = (u_char *) (ip + 1); 797 if ((opts = ip_srcroute()) == 0 && 798 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 799 MCLAIM(opts, m->m_owner); 800 opts->m_len = sizeof(struct in_addr); 801 *mtod(opts, struct in_addr *) = zeroin_addr; 802 } 803 if (opts) { 804 #ifdef ICMPPRINTFS 805 if (icmpprintfs) 806 printf("icmp_reflect optlen %d rt %d => ", 807 optlen, opts->m_len); 808 #endif 809 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 810 opt = cp[IPOPT_OPTVAL]; 811 if (opt == IPOPT_EOL) 812 break; 813 if (opt == IPOPT_NOP) 814 len = 1; 815 else { 816 if (cnt < IPOPT_OLEN + sizeof(*cp)) 817 break; 818 len = cp[IPOPT_OLEN]; 819 if (len < IPOPT_OLEN + sizeof(*cp) || 820 len > cnt) 821 break; 822 } 823 /* 824 * Should check for overflow, but it "can't happen" 825 */ 826 if (opt == IPOPT_RR || opt == IPOPT_TS || 827 opt == IPOPT_SECURITY) { 828 memmove(mtod(opts, char *) + opts->m_len, 829 cp, len); 830 opts->m_len += len; 831 } 832 } 833 /* Terminate & pad, if necessary */ 834 if ((cnt = opts->m_len % 4) != 0) { 835 for (; cnt < 4; cnt++) { 836 *(mtod(opts, char *) + opts->m_len) = 837 IPOPT_EOL; 838 opts->m_len++; 839 } 840 } 841 #ifdef ICMPPRINTFS 842 if (icmpprintfs) 843 printf("%d\n", opts->m_len); 844 #endif 845 } 846 /* 847 * Now strip out original options by copying rest of first 848 * mbuf's data back, and adjust the IP length. 849 */ 850 ip->ip_len = htons(ntohs(ip->ip_len) - optlen); 851 ip->ip_hl = sizeof(struct ip) >> 2; 852 m->m_len -= optlen; 853 if (m->m_flags & M_PKTHDR) 854 m->m_pkthdr.len -= optlen; 855 optlen += sizeof(struct ip); 856 memmove(ip + 1, (char *)ip + optlen, 857 (unsigned)(m->m_len - sizeof(struct ip))); 858 } 859 m_tag_delete_nonpersistent(m); 860 m->m_flags &= ~(M_BCAST|M_MCAST); 861 862 /* 863 * Clear any in-bound checksum flags for this packet. 864 */ 865 if (m->m_flags & M_PKTHDR) 866 m->m_pkthdr.csum_flags = 0; 867 868 icmp_send(m, opts); 869 done: 870 if (opts) 871 (void)m_free(opts); 872 } 873 874 /* 875 * Send an icmp packet back to the ip level, 876 * after supplying a checksum. 877 */ 878 void 879 icmp_send(struct mbuf *m, struct mbuf *opts) 880 { 881 struct ip *ip = mtod(m, struct ip *); 882 int hlen; 883 struct icmp *icp; 884 885 hlen = ip->ip_hl << 2; 886 m->m_data += hlen; 887 m->m_len -= hlen; 888 icp = mtod(m, struct icmp *); 889 icp->icmp_cksum = 0; 890 icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen); 891 m->m_data -= hlen; 892 m->m_len += hlen; 893 #ifdef ICMPPRINTFS 894 if (icmpprintfs) { 895 printf("icmp_send to destination `%s' from `%s'\n", 896 inet_ntoa(ip->ip_dst), inet_ntoa(ip->ip_src)); 897 } 898 #endif 899 (void)ip_output(m, opts, NULL, 0, NULL, NULL); 900 } 901 902 n_time 903 iptime(void) 904 { 905 struct timeval atv; 906 u_long t; 907 908 microtime(&atv); 909 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 910 return (htonl(t)); 911 } 912 913 /* 914 * sysctl helper routine for net.inet.icmp.returndatabytes. ensures 915 * that the new value is in the correct range. 916 */ 917 static int 918 sysctl_net_inet_icmp_returndatabytes(SYSCTLFN_ARGS) 919 { 920 int error, t; 921 struct sysctlnode node; 922 923 node = *rnode; 924 node.sysctl_data = &t; 925 t = icmpreturndatabytes; 926 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 927 if (error || newp == NULL) 928 return (error); 929 930 if (t < 8 || t > 512) 931 return (EINVAL); 932 icmpreturndatabytes = t; 933 934 return (0); 935 } 936 937 /* 938 * sysctl helper routine for net.inet.icmp.redirtimeout. ensures that 939 * the given value is not less than zero and then resets the timeout 940 * queue. 941 */ 942 static int 943 sysctl_net_inet_icmp_redirtimeout(SYSCTLFN_ARGS) 944 { 945 int error, tmp; 946 struct sysctlnode node; 947 948 node = *rnode; 949 node.sysctl_data = &tmp; 950 tmp = icmp_redirtimeout; 951 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 952 if (error || newp == NULL) 953 return (error); 954 if (tmp < 0) 955 return (EINVAL); 956 icmp_redirtimeout = tmp; 957 958 /* 959 * was it a *defined* side-effect that anyone even *reading* 960 * this value causes these things to happen? 961 */ 962 if (icmp_redirect_timeout_q != NULL) { 963 if (icmp_redirtimeout == 0) { 964 rt_timer_queue_destroy(icmp_redirect_timeout_q, 965 true); 966 icmp_redirect_timeout_q = NULL; 967 } else { 968 rt_timer_queue_change(icmp_redirect_timeout_q, 969 icmp_redirtimeout); 970 } 971 } else if (icmp_redirtimeout > 0) { 972 icmp_redirect_timeout_q = 973 rt_timer_queue_create(icmp_redirtimeout); 974 } 975 976 return (0); 977 } 978 979 SYSCTL_SETUP(sysctl_net_inet_icmp_setup, "sysctl net.inet.icmp subtree setup") 980 { 981 982 sysctl_createv(clog, 0, NULL, NULL, 983 CTLFLAG_PERMANENT, 984 CTLTYPE_NODE, "net", NULL, 985 NULL, 0, NULL, 0, 986 CTL_NET, CTL_EOL); 987 sysctl_createv(clog, 0, NULL, NULL, 988 CTLFLAG_PERMANENT, 989 CTLTYPE_NODE, "inet", NULL, 990 NULL, 0, NULL, 0, 991 CTL_NET, PF_INET, CTL_EOL); 992 sysctl_createv(clog, 0, NULL, NULL, 993 CTLFLAG_PERMANENT, 994 CTLTYPE_NODE, "icmp", 995 SYSCTL_DESCR("ICMPv4 related settings"), 996 NULL, 0, NULL, 0, 997 CTL_NET, PF_INET, IPPROTO_ICMP, CTL_EOL); 998 999 sysctl_createv(clog, 0, NULL, NULL, 1000 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1001 CTLTYPE_INT, "maskrepl", 1002 SYSCTL_DESCR("Respond to ICMP_MASKREQ messages"), 1003 NULL, 0, &icmpmaskrepl, 0, 1004 CTL_NET, PF_INET, IPPROTO_ICMP, 1005 ICMPCTL_MASKREPL, CTL_EOL); 1006 sysctl_createv(clog, 0, NULL, NULL, 1007 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1008 CTLTYPE_INT, "returndatabytes", 1009 SYSCTL_DESCR("Number of bytes to return in an ICMP " 1010 "error message"), 1011 sysctl_net_inet_icmp_returndatabytes, 0, 1012 &icmpreturndatabytes, 0, 1013 CTL_NET, PF_INET, IPPROTO_ICMP, 1014 ICMPCTL_RETURNDATABYTES, CTL_EOL); 1015 sysctl_createv(clog, 0, NULL, NULL, 1016 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1017 CTLTYPE_INT, "errppslimit", 1018 SYSCTL_DESCR("Maximum number of outgoing ICMP error " 1019 "messages per second"), 1020 NULL, 0, &icmperrppslim, 0, 1021 CTL_NET, PF_INET, IPPROTO_ICMP, 1022 ICMPCTL_ERRPPSLIMIT, CTL_EOL); 1023 sysctl_createv(clog, 0, NULL, NULL, 1024 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1025 CTLTYPE_INT, "rediraccept", 1026 SYSCTL_DESCR("Accept ICMP_REDIRECT messages"), 1027 NULL, 0, &icmp_rediraccept, 0, 1028 CTL_NET, PF_INET, IPPROTO_ICMP, 1029 ICMPCTL_REDIRACCEPT, CTL_EOL); 1030 sysctl_createv(clog, 0, NULL, NULL, 1031 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1032 CTLTYPE_INT, "redirtimeout", 1033 SYSCTL_DESCR("Lifetime of ICMP_REDIRECT generated " 1034 "routes"), 1035 sysctl_net_inet_icmp_redirtimeout, 0, 1036 &icmp_redirtimeout, 0, 1037 CTL_NET, PF_INET, IPPROTO_ICMP, 1038 ICMPCTL_REDIRTIMEOUT, CTL_EOL); 1039 sysctl_createv(clog, 0, NULL, NULL, 1040 CTLFLAG_PERMANENT, 1041 CTLTYPE_STRUCT, "stats", 1042 SYSCTL_DESCR("ICMP statistics"), 1043 NULL, 0, &icmpstat, sizeof(icmpstat), 1044 CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_STATS, 1045 CTL_EOL); 1046 } 1047 1048 /* Table of common MTUs: */ 1049 1050 static const u_int mtu_table[] = { 1051 65535, 65280, 32000, 17914, 9180, 8166, 1052 4352, 2002, 1492, 1006, 508, 296, 68, 0 1053 }; 1054 1055 void 1056 icmp_mtudisc(struct icmp *icp, struct in_addr faddr) 1057 { 1058 struct icmp_mtudisc_callback *mc; 1059 struct sockaddr *dst = sintosa(&icmpsrc); 1060 struct rtentry *rt; 1061 u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */ 1062 int error; 1063 1064 rt = rtalloc1(dst, 1); 1065 if (rt == 0) 1066 return; 1067 1068 /* If we didn't get a host route, allocate one */ 1069 1070 if ((rt->rt_flags & RTF_HOST) == 0) { 1071 struct rtentry *nrt; 1072 1073 error = rtrequest((int) RTM_ADD, dst, 1074 (struct sockaddr *) rt->rt_gateway, 1075 (struct sockaddr *) 0, 1076 RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt); 1077 if (error) { 1078 rtfree(rt); 1079 return; 1080 } 1081 nrt->rt_rmx = rt->rt_rmx; 1082 rtfree(rt); 1083 rt = nrt; 1084 } 1085 error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q); 1086 if (error) { 1087 rtfree(rt); 1088 return; 1089 } 1090 1091 if (mtu == 0) { 1092 int i = 0; 1093 1094 mtu = ntohs(icp->icmp_ip.ip_len); 1095 /* Some 4.2BSD-based routers incorrectly adjust the ip_len */ 1096 if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0) 1097 mtu -= (icp->icmp_ip.ip_hl << 2); 1098 1099 /* If we still can't guess a value, try the route */ 1100 1101 if (mtu == 0) { 1102 mtu = rt->rt_rmx.rmx_mtu; 1103 1104 /* If no route mtu, default to the interface mtu */ 1105 1106 if (mtu == 0) 1107 mtu = rt->rt_ifp->if_mtu; 1108 } 1109 1110 for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++) 1111 if (mtu > mtu_table[i]) { 1112 mtu = mtu_table[i]; 1113 break; 1114 } 1115 } 1116 1117 /* 1118 * XXX: RTV_MTU is overloaded, since the admin can set it 1119 * to turn off PMTU for a route, and the kernel can 1120 * set it to indicate a serious problem with PMTU 1121 * on a route. We should be using a separate flag 1122 * for the kernel to indicate this. 1123 */ 1124 1125 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 1126 if (mtu < 296 || mtu > rt->rt_ifp->if_mtu) 1127 rt->rt_rmx.rmx_locks |= RTV_MTU; 1128 else if (rt->rt_rmx.rmx_mtu > mtu || 1129 rt->rt_rmx.rmx_mtu == 0) { 1130 icmpstat.icps_pmtuchg++; 1131 rt->rt_rmx.rmx_mtu = mtu; 1132 } 1133 } 1134 1135 if (rt) 1136 rtfree(rt); 1137 1138 /* 1139 * Notify protocols that the MTU for this destination 1140 * has changed. 1141 */ 1142 for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL; 1143 mc = LIST_NEXT(mc, mc_list)) 1144 (*mc->mc_func)(faddr); 1145 } 1146 1147 /* 1148 * Return the next larger or smaller MTU plateau (table from RFC 1191) 1149 * given current value MTU. If DIR is less than zero, a larger plateau 1150 * is returned; otherwise, a smaller value is returned. 1151 */ 1152 u_int 1153 ip_next_mtu(u_int mtu, int dir) /* XXX */ 1154 { 1155 int i; 1156 1157 for (i = 0; i < (sizeof mtu_table) / (sizeof mtu_table[0]); i++) { 1158 if (mtu >= mtu_table[i]) 1159 break; 1160 } 1161 1162 if (dir < 0) { 1163 if (i == 0) { 1164 return 0; 1165 } else { 1166 return mtu_table[i - 1]; 1167 } 1168 } else { 1169 if (mtu_table[i] == 0) { 1170 return 0; 1171 } else if (mtu > mtu_table[i]) { 1172 return mtu_table[i]; 1173 } else { 1174 return mtu_table[i + 1]; 1175 } 1176 } 1177 } 1178 1179 static void 1180 icmp_mtudisc_timeout(struct rtentry *rt, struct rttimer *r) 1181 { 1182 if (rt == NULL) 1183 panic("icmp_mtudisc_timeout: bad route to timeout"); 1184 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 1185 (RTF_DYNAMIC | RTF_HOST)) { 1186 rtrequest((int) RTM_DELETE, rt_getkey(rt), 1187 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 1188 } else { 1189 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 1190 rt->rt_rmx.rmx_mtu = 0; 1191 } 1192 } 1193 } 1194 1195 static void 1196 icmp_redirect_timeout(struct rtentry *rt, struct rttimer *r) 1197 { 1198 if (rt == NULL) 1199 panic("icmp_redirect_timeout: bad route to timeout"); 1200 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 1201 (RTF_DYNAMIC | RTF_HOST)) { 1202 rtrequest((int) RTM_DELETE, rt_getkey(rt), 1203 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 1204 } 1205 } 1206 1207 /* 1208 * Perform rate limit check. 1209 * Returns 0 if it is okay to send the icmp packet. 1210 * Returns 1 if the router SHOULD NOT send this icmp packet due to rate 1211 * limitation. 1212 * 1213 * XXX per-destination/type check necessary? 1214 */ 1215 static int 1216 icmp_ratelimit(const struct in_addr *dst, const int type, 1217 const int code) 1218 { 1219 1220 /* PPS limit */ 1221 if (!ppsratecheck(&icmperrppslim_last, &icmperrpps_count, 1222 icmperrppslim)) { 1223 /* The packet is subject to rate limit */ 1224 return 1; 1225 } 1226 1227 /* okay to send */ 1228 return 0; 1229 } 1230