1 /* $NetBSD: ip_icmp.c,v 1.73 2003/04/17 16:57:49 tron 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. All advertising materials mentioning features or use of this software 85 * must display the following acknowledgement: 86 * This product includes software developed by the University of 87 * California, Berkeley and its contributors. 88 * 4. Neither the name of the University nor the names of its contributors 89 * may be used to endorse or promote products derived from this software 90 * without specific prior written permission. 91 * 92 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 93 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 94 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 95 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 96 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 97 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 98 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 99 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 100 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 101 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 102 * SUCH DAMAGE. 103 * 104 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 105 */ 106 107 #include <sys/cdefs.h> 108 __KERNEL_RCSID(0, "$NetBSD: ip_icmp.c,v 1.73 2003/04/17 16:57:49 tron Exp $"); 109 110 #include "opt_ipsec.h" 111 112 #include <sys/param.h> 113 #include <sys/systm.h> 114 #include <sys/malloc.h> 115 #include <sys/mbuf.h> 116 #include <sys/protosw.h> 117 #include <sys/socket.h> 118 #include <sys/time.h> 119 #include <sys/kernel.h> 120 #include <sys/syslog.h> 121 #include <sys/sysctl.h> 122 123 #include <net/if.h> 124 #include <net/route.h> 125 126 #include <netinet/in.h> 127 #include <netinet/in_systm.h> 128 #include <netinet/in_var.h> 129 #include <netinet/ip.h> 130 #include <netinet/ip_icmp.h> 131 #include <netinet/ip_var.h> 132 #include <netinet/in_pcb.h> 133 #include <netinet/icmp_var.h> 134 135 #ifdef IPSEC 136 #include <netinet6/ipsec.h> 137 #include <netkey/key.h> 138 #endif 139 140 #include <machine/stdarg.h> 141 142 /* 143 * ICMP routines: error generation, receive packet processing, and 144 * routines to turnaround packets back to the originator, and 145 * host table maintenance routines. 146 */ 147 148 int icmpmaskrepl = 0; 149 #ifdef ICMPPRINTFS 150 int icmpprintfs = 0; 151 #endif 152 int icmpreturndatabytes = 8; 153 154 /* 155 * List of callbacks to notify when Path MTU changes are made. 156 */ 157 struct icmp_mtudisc_callback { 158 LIST_ENTRY(icmp_mtudisc_callback) mc_list; 159 void (*mc_func) __P((struct in_addr)); 160 }; 161 162 LIST_HEAD(, icmp_mtudisc_callback) icmp_mtudisc_callbacks = 163 LIST_HEAD_INITIALIZER(&icmp_mtudisc_callbacks); 164 165 #if 0 166 static int ip_next_mtu __P((int, int)); 167 #else 168 /*static*/ int ip_next_mtu __P((int, int)); 169 #endif 170 171 extern int icmperrppslim; 172 static int icmperrpps_count = 0; 173 static struct timeval icmperrppslim_last; 174 static int icmp_rediraccept = 1; 175 static int icmp_redirtimeout = 600; 176 static struct rttimer_queue *icmp_redirect_timeout_q = NULL; 177 178 static void icmp_mtudisc_timeout __P((struct rtentry *, struct rttimer *)); 179 static void icmp_redirect_timeout __P((struct rtentry *, struct rttimer *)); 180 181 static int icmp_ratelimit __P((const struct in_addr *, const int, const int)); 182 183 184 void 185 icmp_init() 186 { 187 /* 188 * This is only useful if the user initializes redirtimeout to 189 * something other than zero. 190 */ 191 if (icmp_redirtimeout != 0) { 192 icmp_redirect_timeout_q = 193 rt_timer_queue_create(icmp_redirtimeout); 194 } 195 } 196 197 /* 198 * Register a Path MTU Discovery callback. 199 */ 200 void 201 icmp_mtudisc_callback_register(func) 202 void (*func) __P((struct in_addr)); 203 { 204 struct icmp_mtudisc_callback *mc; 205 206 for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL; 207 mc = LIST_NEXT(mc, mc_list)) { 208 if (mc->mc_func == func) 209 return; 210 } 211 212 mc = malloc(sizeof(*mc), M_PCB, M_NOWAIT); 213 if (mc == NULL) 214 panic("icmp_mtudisc_callback_register"); 215 216 mc->mc_func = func; 217 LIST_INSERT_HEAD(&icmp_mtudisc_callbacks, mc, mc_list); 218 } 219 220 /* 221 * Generate an error packet of type error 222 * in response to bad packet ip. 223 */ 224 void 225 icmp_error(n, type, code, dest, destifp) 226 struct mbuf *n; 227 int type, code; 228 n_long dest; 229 struct ifnet *destifp; 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 unsigned icmplen, mblen; 236 237 #ifdef ICMPPRINTFS 238 if (icmpprintfs) 239 printf("icmp_error(%x, %d, %d)\n", oip, type, code); 240 #endif 241 if (type != ICMP_REDIRECT) 242 icmpstat.icps_error++; 243 /* 244 * Don't send error if the original packet was encrypted. 245 * Don't send error if not the first fragment of message. 246 * Don't error if the old packet protocol was ICMP 247 * error message, only known informational types. 248 */ 249 if (n->m_flags & M_DECRYPTED) 250 goto freeit; 251 if (oip->ip_off &~ htons(IP_MF|IP_DF)) 252 goto freeit; 253 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 254 n->m_len >= oiplen + ICMP_MINLEN && 255 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { 256 icmpstat.icps_oldicmp++; 257 goto freeit; 258 } 259 /* Don't send error in response to a multicast or broadcast packet */ 260 if (n->m_flags & (M_BCAST|M_MCAST)) 261 goto freeit; 262 263 /* 264 * First, do a rate limitation check. 265 */ 266 if (icmp_ratelimit(&oip->ip_src, type, code)) { 267 /* XXX stat */ 268 goto freeit; 269 } 270 271 /* 272 * Now, formulate icmp message 273 */ 274 icmplen = oiplen + min(icmpreturndatabytes, 275 ntohs(oip->ip_len) - oiplen); 276 /* 277 * Defend against mbuf chains shorter than oip->ip_len: 278 */ 279 mblen = 0; 280 for (m = n; m && (mblen < icmplen); m = m->m_next) 281 mblen += m->m_len; 282 icmplen = min(mblen, icmplen); 283 284 /* 285 * As we are not required to return everything we have, 286 * we return whatever we can return at ease. 287 * 288 * Note that ICMP datagrams longer than 576 octets are out of spec 289 * according to RFC1812; the limit on icmpreturndatabytes below in 290 * icmp_sysctl will keep things below that limit. 291 */ 292 293 KASSERT(ICMP_MINLEN <= MCLBYTES); 294 295 if (icmplen + ICMP_MINLEN > MCLBYTES) 296 icmplen = MCLBYTES - ICMP_MINLEN; 297 298 m = m_gethdr(M_DONTWAIT, MT_HEADER); 299 if (m && (icmplen + ICMP_MINLEN > MHLEN)) { 300 MCLGET(m, M_DONTWAIT); 301 if ((m->m_flags & M_EXT) == 0) { 302 m_freem(m); 303 m = NULL; 304 } 305 } 306 if (m == NULL) 307 goto freeit; 308 MCLAIM(m, n->m_owner); 309 m->m_len = icmplen + ICMP_MINLEN; 310 if ((m->m_flags & M_EXT) == 0) 311 MH_ALIGN(m, m->m_len); 312 icp = mtod(m, struct icmp *); 313 if ((u_int)type > ICMP_MAXTYPE) 314 panic("icmp_error"); 315 icmpstat.icps_outhist[type]++; 316 icp->icmp_type = type; 317 if (type == ICMP_REDIRECT) 318 icp->icmp_gwaddr.s_addr = dest; 319 else { 320 icp->icmp_void = 0; 321 /* 322 * The following assignments assume an overlay with the 323 * zeroed icmp_void field. 324 */ 325 if (type == ICMP_PARAMPROB) { 326 icp->icmp_pptr = code; 327 code = 0; 328 } else if (type == ICMP_UNREACH && 329 code == ICMP_UNREACH_NEEDFRAG && destifp) 330 icp->icmp_nextmtu = htons(destifp->if_mtu); 331 } 332 333 icp->icmp_code = code; 334 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip); 335 nip = &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 icmp_reflect(m); 359 360 freeit: 361 m_freem(n); 362 } 363 364 static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; 365 static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; 366 static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; 367 struct sockaddr_in icmpmask = { 8, 0 }; 368 369 /* 370 * Process a received ICMP message. 371 */ 372 void 373 #if __STDC__ 374 icmp_input(struct mbuf *m, ...) 375 #else 376 icmp_input(m, va_alist) 377 struct mbuf *m; 378 va_dcl 379 #endif 380 { 381 int proto; 382 struct icmp *icp; 383 struct ip *ip = mtod(m, struct ip *); 384 int icmplen; 385 int i; 386 struct in_ifaddr *ia; 387 void *(*ctlfunc) __P((int, struct sockaddr *, void *)); 388 int code; 389 int hlen; 390 va_list ap; 391 struct rtentry *rt; 392 393 va_start(ap, m); 394 hlen = va_arg(ap, int); 395 proto = va_arg(ap, int); 396 va_end(ap); 397 398 /* 399 * Locate icmp structure in mbuf, and check 400 * that not corrupted and of at least minimum length. 401 */ 402 icmplen = ntohs(ip->ip_len) - hlen; 403 #ifdef ICMPPRINTFS 404 if (icmpprintfs) 405 printf("icmp_input from %x to %x, len %d\n", 406 ntohl(ip->ip_src.s_addr), ntohl(ip->ip_dst.s_addr), 407 icmplen); 408 #endif 409 if (icmplen < ICMP_MINLEN) { 410 icmpstat.icps_tooshort++; 411 goto freeit; 412 } 413 i = hlen + min(icmplen, ICMP_ADVLENMIN); 414 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 415 icmpstat.icps_tooshort++; 416 return; 417 } 418 ip = mtod(m, struct ip *); 419 m->m_len -= hlen; 420 m->m_data += hlen; 421 icp = mtod(m, struct icmp *); 422 /* Don't need to assert alignment, here. */ 423 if (in_cksum(m, icmplen)) { 424 icmpstat.icps_checksum++; 425 goto freeit; 426 } 427 m->m_len += hlen; 428 m->m_data -= hlen; 429 430 #ifdef ICMPPRINTFS 431 /* 432 * Message type specific processing. 433 */ 434 if (icmpprintfs) 435 printf("icmp_input, type %d code %d\n", icp->icmp_type, 436 icp->icmp_code); 437 #endif 438 if (icp->icmp_type > ICMP_MAXTYPE) 439 goto raw; 440 icmpstat.icps_inhist[icp->icmp_type]++; 441 code = icp->icmp_code; 442 switch (icp->icmp_type) { 443 444 case ICMP_UNREACH: 445 switch (code) { 446 case ICMP_UNREACH_NET: 447 case ICMP_UNREACH_HOST: 448 case ICMP_UNREACH_PROTOCOL: 449 case ICMP_UNREACH_PORT: 450 case ICMP_UNREACH_SRCFAIL: 451 code += PRC_UNREACH_NET; 452 break; 453 454 case ICMP_UNREACH_NEEDFRAG: 455 code = PRC_MSGSIZE; 456 break; 457 458 case ICMP_UNREACH_NET_UNKNOWN: 459 case ICMP_UNREACH_NET_PROHIB: 460 case ICMP_UNREACH_TOSNET: 461 code = PRC_UNREACH_NET; 462 break; 463 464 case ICMP_UNREACH_HOST_UNKNOWN: 465 case ICMP_UNREACH_ISOLATED: 466 case ICMP_UNREACH_HOST_PROHIB: 467 case ICMP_UNREACH_TOSHOST: 468 code = PRC_UNREACH_HOST; 469 break; 470 471 default: 472 goto badcode; 473 } 474 goto deliver; 475 476 case ICMP_TIMXCEED: 477 if (code > 1) 478 goto badcode; 479 code += PRC_TIMXCEED_INTRANS; 480 goto deliver; 481 482 case ICMP_PARAMPROB: 483 if (code > 1) 484 goto badcode; 485 code = PRC_PARAMPROB; 486 goto deliver; 487 488 case ICMP_SOURCEQUENCH: 489 if (code) 490 goto badcode; 491 code = PRC_QUENCH; 492 goto deliver; 493 494 deliver: 495 /* 496 * Problem with datagram; advise higher level routines. 497 */ 498 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 499 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 500 icmpstat.icps_badlen++; 501 goto freeit; 502 } 503 if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr)) 504 goto badcode; 505 #ifdef ICMPPRINTFS 506 if (icmpprintfs) 507 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 508 #endif 509 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 510 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 511 if (ctlfunc) 512 (void) (*ctlfunc)(code, sintosa(&icmpsrc), 513 &icp->icmp_ip); 514 break; 515 516 badcode: 517 icmpstat.icps_badcode++; 518 break; 519 520 case ICMP_ECHO: 521 icp->icmp_type = ICMP_ECHOREPLY; 522 goto reflect; 523 524 case ICMP_TSTAMP: 525 if (icmplen < ICMP_TSLEN) { 526 icmpstat.icps_badlen++; 527 break; 528 } 529 icp->icmp_type = ICMP_TSTAMPREPLY; 530 icp->icmp_rtime = iptime(); 531 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 532 goto reflect; 533 534 case ICMP_MASKREQ: 535 if (icmpmaskrepl == 0) 536 break; 537 /* 538 * We are not able to respond with all ones broadcast 539 * unless we receive it over a point-to-point interface. 540 */ 541 if (icmplen < ICMP_MASKLEN) { 542 icmpstat.icps_badlen++; 543 break; 544 } 545 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 546 in_nullhost(ip->ip_dst)) 547 icmpdst.sin_addr = ip->ip_src; 548 else 549 icmpdst.sin_addr = ip->ip_dst; 550 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 551 m->m_pkthdr.rcvif)); 552 if (ia == 0) 553 break; 554 icp->icmp_type = ICMP_MASKREPLY; 555 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 556 if (in_nullhost(ip->ip_src)) { 557 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 558 ip->ip_src = ia->ia_broadaddr.sin_addr; 559 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 560 ip->ip_src = ia->ia_dstaddr.sin_addr; 561 } 562 reflect: 563 icmpstat.icps_reflect++; 564 icmpstat.icps_outhist[icp->icmp_type]++; 565 icmp_reflect(m); 566 return; 567 568 case ICMP_REDIRECT: 569 if (code > 3) 570 goto badcode; 571 if (icmp_rediraccept == 0) 572 goto freeit; 573 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 574 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 575 icmpstat.icps_badlen++; 576 break; 577 } 578 /* 579 * Short circuit routing redirects to force 580 * immediate change in the kernel's routing 581 * tables. The message is also handed to anyone 582 * listening on a raw socket (e.g. the routing 583 * daemon for use in updating its tables). 584 */ 585 icmpgw.sin_addr = ip->ip_src; 586 icmpdst.sin_addr = icp->icmp_gwaddr; 587 #ifdef ICMPPRINTFS 588 if (icmpprintfs) 589 printf("redirect dst %x to %x\n", icp->icmp_ip.ip_dst, 590 icp->icmp_gwaddr); 591 #endif 592 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 593 rt = NULL; 594 rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst), 595 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 596 sintosa(&icmpgw), (struct rtentry **)&rt); 597 if (rt != NULL && icmp_redirtimeout != 0) { 598 i = rt_timer_add(rt, icmp_redirect_timeout, 599 icmp_redirect_timeout_q); 600 if (i) 601 log(LOG_ERR, "ICMP: redirect failed to " 602 "register timeout for route to %x, " 603 "code %d\n", 604 icp->icmp_ip.ip_dst.s_addr, i); 605 } 606 if (rt != NULL) 607 rtfree(rt); 608 609 pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc)); 610 #ifdef IPSEC 611 key_sa_routechange((struct sockaddr *)&icmpsrc); 612 #endif 613 break; 614 615 /* 616 * No kernel processing for the following; 617 * just fall through to send to raw listener. 618 */ 619 case ICMP_ECHOREPLY: 620 case ICMP_ROUTERADVERT: 621 case ICMP_ROUTERSOLICIT: 622 case ICMP_TSTAMPREPLY: 623 case ICMP_IREQREPLY: 624 case ICMP_MASKREPLY: 625 default: 626 break; 627 } 628 629 raw: 630 rip_input(m, hlen, proto); 631 return; 632 633 freeit: 634 m_freem(m); 635 return; 636 } 637 638 /* 639 * Reflect the ip packet back to the source 640 */ 641 void 642 icmp_reflect(m) 643 struct mbuf *m; 644 { 645 struct ip *ip = mtod(m, struct ip *); 646 struct in_ifaddr *ia; 647 struct ifaddr *ifa; 648 struct sockaddr_in *sin = 0; 649 struct in_addr t; 650 struct mbuf *opts = 0; 651 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 652 653 if (!in_canforward(ip->ip_src) && 654 ((ip->ip_src.s_addr & IN_CLASSA_NET) != 655 htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 656 m_freem(m); /* Bad return address */ 657 goto done; /* ip_output() will check for broadcast */ 658 } 659 t = ip->ip_dst; 660 ip->ip_dst = ip->ip_src; 661 /* 662 * If the incoming packet was addressed directly to us, use 663 * dst as the src for the reply. Otherwise (broadcast or 664 * anonymous), use an address which corresponds to the 665 * incoming interface, with a preference for the address which 666 * corresponds to the route to the destination of the ICMP. 667 */ 668 669 /* Look for packet addressed to us */ 670 INADDR_TO_IA(t, ia); 671 672 /* look for packet sent to broadcast address */ 673 if (ia == NULL && (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 674 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrlist, ifa_list) { 675 if (ifa->ifa_addr->sa_family != AF_INET) 676 continue; 677 if (in_hosteq(t,ifatoia(ifa)->ia_broadaddr.sin_addr)) { 678 ia = ifatoia(ifa); 679 break; 680 } 681 } 682 } 683 684 if (ia) 685 sin = &ia->ia_addr; 686 687 icmpdst.sin_addr = t; 688 689 /* 690 * if the packet is addressed somewhere else, compute the 691 * source address for packets routed back to the source, and 692 * use that, if it's an address on the interface which 693 * received the packet 694 */ 695 if (sin == (struct sockaddr_in *)0) { 696 struct sockaddr_in sin_dst; 697 struct route icmproute; 698 int errornum; 699 700 sin_dst.sin_family = AF_INET; 701 sin_dst.sin_len = sizeof(struct sockaddr_in); 702 sin_dst.sin_addr = ip->ip_dst; 703 bzero(&icmproute, sizeof(icmproute)); 704 errornum = 0; 705 sin = in_selectsrc(&sin_dst, &icmproute, 0, NULL, &errornum); 706 /* errornum is never used */ 707 if (icmproute.ro_rt) 708 RTFREE(icmproute.ro_rt); 709 /* check to make sure sin is a source address on rcvif */ 710 if (sin) { 711 t = sin->sin_addr; 712 sin = (struct sockaddr_in *)0; 713 INADDR_TO_IA(t, ia); 714 while (ia) { 715 if (ia->ia_ifp == m->m_pkthdr.rcvif) { 716 sin = &ia->ia_addr; 717 break; 718 } 719 NEXT_IA_WITH_SAME_ADDR(ia); 720 } 721 } 722 } 723 724 /* 725 * if it was not addressed to us, but the route doesn't go out 726 * the source interface, pick an address on the source 727 * interface. This can happen when routing is asymmetric, or 728 * when the incoming packet was encapsulated 729 */ 730 if (sin == (struct sockaddr_in *)0) { 731 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrlist, ifa_list) { 732 if (ifa->ifa_addr->sa_family != AF_INET) 733 continue; 734 sin = &(ifatoia(ifa)->ia_addr); 735 break; 736 } 737 } 738 739 /* 740 * The following happens if the packet was not addressed to us, 741 * and was received on an interface with no IP address: 742 * We find the first AF_INET address on the first non-loopback 743 * interface. 744 */ 745 if (sin == (struct sockaddr_in *)0) 746 TAILQ_FOREACH(ia, &in_ifaddr, ia_list) { 747 if (ia->ia_ifp->if_flags & IFF_LOOPBACK) 748 continue; 749 sin = &ia->ia_addr; 750 break; 751 } 752 753 /* 754 * If we still didn't find an address, punt. We could have an 755 * interface up (and receiving packets) with no address. 756 */ 757 if (sin == (struct sockaddr_in *)0) { 758 m_freem(m); 759 goto done; 760 } 761 762 ip->ip_src = sin->sin_addr; 763 ip->ip_ttl = MAXTTL; 764 765 if (optlen > 0) { 766 u_char *cp; 767 int opt, cnt; 768 u_int len; 769 770 /* 771 * Retrieve any source routing from the incoming packet; 772 * add on any record-route or timestamp options. 773 */ 774 cp = (u_char *) (ip + 1); 775 if ((opts = ip_srcroute()) == 0 && 776 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 777 MCLAIM(opts, m->m_owner); 778 opts->m_len = sizeof(struct in_addr); 779 *mtod(opts, struct in_addr *) = zeroin_addr; 780 } 781 if (opts) { 782 #ifdef ICMPPRINTFS 783 if (icmpprintfs) 784 printf("icmp_reflect optlen %d rt %d => ", 785 optlen, opts->m_len); 786 #endif 787 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 788 opt = cp[IPOPT_OPTVAL]; 789 if (opt == IPOPT_EOL) 790 break; 791 if (opt == IPOPT_NOP) 792 len = 1; 793 else { 794 if (cnt < IPOPT_OLEN + sizeof(*cp)) 795 break; 796 len = cp[IPOPT_OLEN]; 797 if (len < IPOPT_OLEN + sizeof(*cp) || 798 len > cnt) 799 break; 800 } 801 /* 802 * Should check for overflow, but it "can't happen" 803 */ 804 if (opt == IPOPT_RR || opt == IPOPT_TS || 805 opt == IPOPT_SECURITY) { 806 bcopy((caddr_t)cp, 807 mtod(opts, caddr_t) + opts->m_len, len); 808 opts->m_len += len; 809 } 810 } 811 /* Terminate & pad, if necessary */ 812 if ((cnt = opts->m_len % 4) != 0) { 813 for (; cnt < 4; cnt++) { 814 *(mtod(opts, caddr_t) + opts->m_len) = 815 IPOPT_EOL; 816 opts->m_len++; 817 } 818 } 819 #ifdef ICMPPRINTFS 820 if (icmpprintfs) 821 printf("%d\n", opts->m_len); 822 #endif 823 } 824 /* 825 * Now strip out original options by copying rest of first 826 * mbuf's data back, and adjust the IP length. 827 */ 828 ip->ip_len = htons(ntohs(ip->ip_len) - optlen); 829 ip->ip_hl = sizeof(struct ip) >> 2; 830 m->m_len -= optlen; 831 if (m->m_flags & M_PKTHDR) 832 m->m_pkthdr.len -= optlen; 833 optlen += sizeof(struct ip); 834 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 835 (unsigned)(m->m_len - sizeof(struct ip))); 836 } 837 m->m_flags &= ~(M_BCAST|M_MCAST); 838 839 /* 840 * Clear any in-bound checksum flags for this packet. 841 */ 842 m->m_pkthdr.csum_flags = 0; 843 844 icmp_send(m, opts); 845 done: 846 if (opts) 847 (void)m_free(opts); 848 } 849 850 /* 851 * Send an icmp packet back to the ip level, 852 * after supplying a checksum. 853 */ 854 void 855 icmp_send(m, opts) 856 struct mbuf *m; 857 struct mbuf *opts; 858 { 859 struct ip *ip = mtod(m, struct ip *); 860 int hlen; 861 struct icmp *icp; 862 863 hlen = ip->ip_hl << 2; 864 m->m_data += hlen; 865 m->m_len -= hlen; 866 icp = mtod(m, struct icmp *); 867 icp->icmp_cksum = 0; 868 icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen); 869 m->m_data -= hlen; 870 m->m_len += hlen; 871 #ifdef ICMPPRINTFS 872 if (icmpprintfs) 873 printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src); 874 #endif 875 #ifdef IPSEC 876 /* Don't lookup socket */ 877 (void)ipsec_setsocket(m, NULL); 878 #endif 879 (void) ip_output(m, opts, NULL, 0, NULL); 880 } 881 882 n_time 883 iptime() 884 { 885 struct timeval atv; 886 u_long t; 887 888 microtime(&atv); 889 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 890 return (htonl(t)); 891 } 892 893 int 894 icmp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 895 int *name; 896 u_int namelen; 897 void *oldp; 898 size_t *oldlenp; 899 void *newp; 900 size_t newlen; 901 { 902 int arg, error; 903 904 /* All sysctl names at this level are terminal. */ 905 if (namelen != 1) 906 return (ENOTDIR); 907 908 switch (name[0]) 909 { 910 case ICMPCTL_MASKREPL: 911 error = sysctl_int(oldp, oldlenp, newp, newlen, &icmpmaskrepl); 912 break; 913 case ICMPCTL_RETURNDATABYTES: 914 arg = icmpreturndatabytes; 915 error = sysctl_int(oldp, oldlenp, newp, newlen, &arg); 916 if (error) 917 break; 918 if ((arg >= 8) || (arg <= 512)) 919 icmpreturndatabytes = arg; 920 else 921 error = EINVAL; 922 break; 923 case ICMPCTL_ERRPPSLIMIT: 924 error = sysctl_int(oldp, oldlenp, newp, newlen, &icmperrppslim); 925 break; 926 case ICMPCTL_REDIRACCEPT: 927 error = sysctl_int(oldp, oldlenp, newp, newlen, 928 &icmp_rediraccept); 929 break; 930 case ICMPCTL_REDIRTIMEOUT: 931 error = sysctl_int(oldp, oldlenp, newp, newlen, 932 &icmp_redirtimeout); 933 if (icmp_redirect_timeout_q != NULL) { 934 if (icmp_redirtimeout == 0) { 935 rt_timer_queue_destroy(icmp_redirect_timeout_q, 936 TRUE); 937 icmp_redirect_timeout_q = NULL; 938 } else { 939 rt_timer_queue_change(icmp_redirect_timeout_q, 940 icmp_redirtimeout); 941 } 942 } else if (icmp_redirtimeout > 0) { 943 icmp_redirect_timeout_q = 944 rt_timer_queue_create(icmp_redirtimeout); 945 } 946 return (error); 947 default: 948 error = ENOPROTOOPT; 949 break; 950 } 951 return error; 952 } 953 954 /* Table of common MTUs: */ 955 956 static const u_int mtu_table[] = { 957 65535, 65280, 32000, 17914, 9180, 8166, 958 4352, 2002, 1492, 1006, 508, 296, 68, 0 959 }; 960 961 void 962 icmp_mtudisc(icp, faddr) 963 struct icmp *icp; 964 struct in_addr faddr; 965 { 966 struct icmp_mtudisc_callback *mc; 967 struct sockaddr *dst = sintosa(&icmpsrc); 968 struct rtentry *rt; 969 u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */ 970 int error; 971 972 rt = rtalloc1(dst, 1); 973 if (rt == 0) 974 return; 975 976 /* If we didn't get a host route, allocate one */ 977 978 if ((rt->rt_flags & RTF_HOST) == 0) { 979 struct rtentry *nrt; 980 981 error = rtrequest((int) RTM_ADD, dst, 982 (struct sockaddr *) rt->rt_gateway, 983 (struct sockaddr *) 0, 984 RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt); 985 if (error) { 986 rtfree(rt); 987 return; 988 } 989 nrt->rt_rmx = rt->rt_rmx; 990 rtfree(rt); 991 rt = nrt; 992 } 993 error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q); 994 if (error) { 995 rtfree(rt); 996 return; 997 } 998 999 if (mtu == 0) { 1000 int i = 0; 1001 1002 mtu = ntohs(icp->icmp_ip.ip_len); 1003 /* Some 4.2BSD-based routers incorrectly adjust the ip_len */ 1004 if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0) 1005 mtu -= (icp->icmp_ip.ip_hl << 2); 1006 1007 /* If we still can't guess a value, try the route */ 1008 1009 if (mtu == 0) { 1010 mtu = rt->rt_rmx.rmx_mtu; 1011 1012 /* If no route mtu, default to the interface mtu */ 1013 1014 if (mtu == 0) 1015 mtu = rt->rt_ifp->if_mtu; 1016 } 1017 1018 for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++) 1019 if (mtu > mtu_table[i]) { 1020 mtu = mtu_table[i]; 1021 break; 1022 } 1023 } 1024 1025 /* 1026 * XXX: RTV_MTU is overloaded, since the admin can set it 1027 * to turn off PMTU for a route, and the kernel can 1028 * set it to indicate a serious problem with PMTU 1029 * on a route. We should be using a separate flag 1030 * for the kernel to indicate this. 1031 */ 1032 1033 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 1034 if (mtu < 296 || mtu > rt->rt_ifp->if_mtu) 1035 rt->rt_rmx.rmx_locks |= RTV_MTU; 1036 else if (rt->rt_rmx.rmx_mtu > mtu || 1037 rt->rt_rmx.rmx_mtu == 0) { 1038 icmpstat.icps_pmtuchg++; 1039 rt->rt_rmx.rmx_mtu = mtu; 1040 } 1041 } 1042 1043 if (rt) 1044 rtfree(rt); 1045 1046 /* 1047 * Notify protocols that the MTU for this destination 1048 * has changed. 1049 */ 1050 for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL; 1051 mc = LIST_NEXT(mc, mc_list)) 1052 (*mc->mc_func)(faddr); 1053 } 1054 1055 /* 1056 * Return the next larger or smaller MTU plateau (table from RFC 1191) 1057 * given current value MTU. If DIR is less than zero, a larger plateau 1058 * is returned; otherwise, a smaller value is returned. 1059 */ 1060 int 1061 ip_next_mtu(mtu, dir) /* XXX */ 1062 int mtu; 1063 int dir; 1064 { 1065 int i; 1066 1067 for (i = 0; i < (sizeof mtu_table) / (sizeof mtu_table[0]); i++) { 1068 if (mtu >= mtu_table[i]) 1069 break; 1070 } 1071 1072 if (dir < 0) { 1073 if (i == 0) { 1074 return 0; 1075 } else { 1076 return mtu_table[i - 1]; 1077 } 1078 } else { 1079 if (mtu_table[i] == 0) { 1080 return 0; 1081 } else if (mtu > mtu_table[i]) { 1082 return mtu_table[i]; 1083 } else { 1084 return mtu_table[i + 1]; 1085 } 1086 } 1087 } 1088 1089 static void 1090 icmp_mtudisc_timeout(rt, r) 1091 struct rtentry *rt; 1092 struct rttimer *r; 1093 { 1094 if (rt == NULL) 1095 panic("icmp_mtudisc_timeout: bad route to timeout"); 1096 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 1097 (RTF_DYNAMIC | RTF_HOST)) { 1098 rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt), 1099 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 1100 } else { 1101 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 1102 rt->rt_rmx.rmx_mtu = 0; 1103 } 1104 } 1105 } 1106 1107 static void 1108 icmp_redirect_timeout(rt, r) 1109 struct rtentry *rt; 1110 struct rttimer *r; 1111 { 1112 if (rt == NULL) 1113 panic("icmp_redirect_timeout: bad route to timeout"); 1114 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 1115 (RTF_DYNAMIC | RTF_HOST)) { 1116 rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt), 1117 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 1118 } 1119 } 1120 1121 /* 1122 * Perform rate limit check. 1123 * Returns 0 if it is okay to send the icmp packet. 1124 * Returns 1 if the router SHOULD NOT send this icmp packet due to rate 1125 * limitation. 1126 * 1127 * XXX per-destination/type check necessary? 1128 */ 1129 static int 1130 icmp_ratelimit(dst, type, code) 1131 const struct in_addr *dst; 1132 const int type; /* not used at this moment */ 1133 const int code; /* not used at this moment */ 1134 { 1135 1136 /* PPS limit */ 1137 if (!ppsratecheck(&icmperrppslim_last, &icmperrpps_count, 1138 icmperrppslim)) { 1139 /* The packet is subject to rate limit */ 1140 return 1; 1141 } 1142 1143 /*okay to send*/ 1144 return 0; 1145 } 1146