ip_icmp.c revision 1.162
1 /* $NetBSD: ip_icmp.c,v 1.162 2018/01/19 12:50:27 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) 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 * 52 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 53 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 54 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 55 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 56 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 57 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 58 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 59 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 60 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 61 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 62 * POSSIBILITY OF SUCH DAMAGE. 63 */ 64 65 /* 66 * Copyright (c) 1982, 1986, 1988, 1993 67 * The Regents of the University of California. All rights reserved. 68 * 69 * Redistribution and use in source and binary forms, with or without 70 * modification, are permitted provided that the following conditions 71 * are met: 72 * 1. Redistributions of source code must retain the above copyright 73 * notice, this list of conditions and the following disclaimer. 74 * 2. Redistributions in binary form must reproduce the above copyright 75 * notice, this list of conditions and the following disclaimer in the 76 * documentation and/or other materials provided with the distribution. 77 * 3. Neither the name of the University nor the names of its contributors 78 * may be used to endorse or promote products derived from this software 79 * without specific prior written permission. 80 * 81 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 82 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 83 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 84 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 85 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 86 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 87 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 88 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 89 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 90 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 91 * SUCH DAMAGE. 92 * 93 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 94 */ 95 96 #include <sys/cdefs.h> 97 __KERNEL_RCSID(0, "$NetBSD: ip_icmp.c,v 1.162 2018/01/19 12:50:27 maxv Exp $"); 98 99 #ifdef _KERNEL_OPT 100 #include "opt_ipsec.h" 101 #endif 102 103 #include <sys/param.h> 104 #include <sys/systm.h> 105 #include <sys/mbuf.h> 106 #include <sys/protosw.h> 107 #include <sys/socket.h> 108 #include <sys/socketvar.h> /* For softnet_lock */ 109 #include <sys/kmem.h> 110 #include <sys/time.h> 111 #include <sys/kernel.h> 112 #include <sys/syslog.h> 113 #include <sys/sysctl.h> 114 115 #include <net/if.h> 116 #include <net/route.h> 117 118 #include <netinet/in.h> 119 #include <netinet/in_systm.h> 120 #include <netinet/in_var.h> 121 #include <netinet/ip.h> 122 #include <netinet/ip_icmp.h> 123 #include <netinet/ip_var.h> 124 #include <netinet/in_pcb.h> 125 #include <netinet/in_proto.h> 126 #include <netinet/icmp_var.h> 127 #include <netinet/icmp_private.h> 128 #include <netinet/wqinput.h> 129 130 #ifdef IPSEC 131 #include <netipsec/ipsec.h> 132 #include <netipsec/key.h> 133 #endif /* IPSEC*/ 134 135 /* 136 * ICMP routines: error generation, receive packet processing, and 137 * routines to turnaround packets back to the originator, and 138 * host table maintenance routines. 139 */ 140 141 int icmpmaskrepl = 0; 142 int icmpbmcastecho = 0; 143 #ifdef ICMPPRINTFS 144 int icmpprintfs = 0; 145 #endif 146 int icmpreturndatabytes = 8; 147 148 percpu_t *icmpstat_percpu; 149 150 /* 151 * List of callbacks to notify when Path MTU changes are made. 152 */ 153 struct icmp_mtudisc_callback { 154 LIST_ENTRY(icmp_mtudisc_callback) mc_list; 155 void (*mc_func)(struct in_addr); 156 }; 157 158 LIST_HEAD(, icmp_mtudisc_callback) icmp_mtudisc_callbacks = 159 LIST_HEAD_INITIALIZER(&icmp_mtudisc_callbacks); 160 161 #if 0 162 static u_int ip_next_mtu(u_int, int); 163 #else 164 /*static*/ u_int ip_next_mtu(u_int, int); 165 #endif 166 167 extern int icmperrppslim; 168 static int icmperrpps_count = 0; 169 static struct timeval icmperrppslim_last; 170 static int icmp_rediraccept = 1; 171 static int icmp_redirtimeout = 600; 172 static struct rttimer_queue *icmp_redirect_timeout_q = NULL; 173 174 /* Protect mtudisc and redirect stuffs */ 175 static kmutex_t icmp_mtx __cacheline_aligned; 176 177 static void icmp_mtudisc_timeout(struct rtentry *, struct rttimer *); 178 static void icmp_redirect_timeout(struct rtentry *, struct rttimer *); 179 180 static void sysctl_netinet_icmp_setup(struct sysctllog **); 181 182 /* workqueue-based pr_input */ 183 static struct wqinput *icmp_wqinput; 184 static void _icmp_input(struct mbuf *, int, int); 185 186 void 187 icmp_init(void) 188 { 189 190 sysctl_netinet_icmp_setup(NULL); 191 192 mutex_init(&icmp_mtx, MUTEX_DEFAULT, IPL_NONE); 193 /* 194 * This is only useful if the user initializes redirtimeout to 195 * something other than zero. 196 */ 197 mutex_enter(&icmp_mtx); 198 icmp_redirect_timeout_q = rt_timer_queue_create(icmp_redirtimeout); 199 mutex_exit(&icmp_mtx); 200 201 icmpstat_percpu = percpu_alloc(sizeof(uint64_t) * ICMP_NSTATS); 202 icmp_wqinput = wqinput_create("icmp", _icmp_input); 203 } 204 205 void 206 icmp_mtudisc_lock(void) 207 { 208 209 mutex_enter(&icmp_mtx); 210 } 211 212 void 213 icmp_mtudisc_unlock(void) 214 { 215 216 mutex_exit(&icmp_mtx); 217 } 218 219 /* 220 * Register a Path MTU Discovery callback. 221 */ 222 void 223 icmp_mtudisc_callback_register(void (*func)(struct in_addr)) 224 { 225 struct icmp_mtudisc_callback *mc, *new; 226 227 new = kmem_alloc(sizeof(*mc), KM_SLEEP); 228 229 mutex_enter(&icmp_mtx); 230 for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL; 231 mc = LIST_NEXT(mc, mc_list)) { 232 if (mc->mc_func == func) { 233 mutex_exit(&icmp_mtx); 234 kmem_free(new, sizeof(*mc)); 235 return; 236 } 237 } 238 239 new->mc_func = func; 240 LIST_INSERT_HEAD(&icmp_mtudisc_callbacks, new, mc_list); 241 mutex_exit(&icmp_mtx); 242 } 243 244 /* 245 * Generate an error packet of type error in response to a bad IP packet. 'n' 246 * contains this packet. We create 'm' and send it. 247 * 248 * As we are not required to return everything we have, we return whatever 249 * we can return at ease. 250 * 251 * Note that ICMP datagrams longer than 576 octets are out of spec according 252 * to RFC1812; the limit on icmpreturndatabytes will keep things below that 253 * limit. 254 */ 255 void 256 icmp_error(struct mbuf *n, int type, int code, n_long dest, int destmtu) 257 { 258 struct ip *oip = mtod(n, struct ip *), *nip; 259 const unsigned oiphlen = oip->ip_hl << 2; 260 struct icmp *icp; 261 struct mbuf *m; 262 struct m_tag *mtag; 263 unsigned datalen, mblen, totlen; 264 265 #ifdef ICMPPRINTFS 266 if (icmpprintfs) 267 printf("icmp_error(%p, type:%d, code:%d)\n", oip, type, code); 268 #endif 269 270 if (type != ICMP_REDIRECT) 271 ICMP_STATINC(ICMP_STAT_ERROR); 272 273 /* 274 * Don't send error if: 275 * - The original packet was encrypted. 276 * - The packet is multicast or broadcast. 277 * - The packet is not the first fragment of the message. 278 * - The packet is an ICMP message with an unknown type. 279 */ 280 if (n->m_flags & M_DECRYPTED) 281 goto freeit; 282 if (n->m_flags & (M_BCAST|M_MCAST)) 283 goto freeit; 284 if (oip->ip_off &~ htons(IP_MF|IP_DF)) 285 goto freeit; 286 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 287 n->m_len >= oiphlen + ICMP_MINLEN) { 288 struct icmp *oicp = (struct icmp *)((char *)oip + oiphlen); 289 if (!ICMP_INFOTYPE(oicp->icmp_type)) { 290 ICMP_STATINC(ICMP_STAT_OLDICMP); 291 goto freeit; 292 } 293 } 294 295 /* 296 * First, do a rate limitation check. 297 */ 298 if (icmp_ratelimit(&oip->ip_src, type, code)) { 299 /* XXX stat */ 300 goto freeit; 301 } 302 303 /* 304 * Compute the number of bytes we will put in 'icmp_ip'. Truncate 305 * it to the size of the mbuf, if it's too big. 306 */ 307 datalen = oiphlen + min(icmpreturndatabytes, 308 ntohs(oip->ip_len) - oiphlen); 309 mblen = 0; 310 for (m = n; m && (mblen < datalen); m = m->m_next) 311 mblen += m->m_len; 312 datalen = min(mblen, datalen); 313 314 /* 315 * Compute the total length of the new packet. Truncate it if it's 316 * bigger than the size of a cluster. 317 */ 318 CTASSERT(ICMP_MINLEN <= MCLBYTES); 319 if (datalen + ICMP_MINLEN > MCLBYTES) 320 datalen = MCLBYTES - ICMP_MINLEN; 321 totlen = datalen + ICMP_MINLEN; 322 323 /* 324 * Allocate the mbuf for the new packet. 325 */ 326 m = m_gethdr(M_DONTWAIT, MT_HEADER); 327 if (m && (totlen > MHLEN)) { 328 MCLGET(m, M_DONTWAIT); 329 if ((m->m_flags & M_EXT) == 0) { 330 m_freem(m); 331 m = NULL; 332 } 333 } 334 if (m == NULL) 335 goto freeit; 336 MCLAIM(m, n->m_owner); 337 m->m_len = totlen; 338 339 /* 340 * Advance to the ICMP header. 341 */ 342 if ((m->m_flags & M_EXT) == 0) { 343 MH_ALIGN(m, m->m_len); 344 } else { 345 m->m_data += sizeof(struct ip); 346 m->m_len -= sizeof(struct ip); 347 } 348 349 if ((u_int)type > ICMP_MAXTYPE) 350 panic("icmp_error"); 351 ICMP_STATINC(ICMP_STAT_OUTHIST + type); 352 353 /* 354 * Fill in the fields of the ICMP header: icmp_type, icmp_code 355 * and icmp_ip. icmp_cksum gets filled later. 356 */ 357 icp = mtod(m, struct icmp *); 358 icp->icmp_type = type; 359 if (type == ICMP_REDIRECT) { 360 icp->icmp_gwaddr.s_addr = dest; 361 } else { 362 icp->icmp_void = 0; 363 /* 364 * The following assignments assume an overlay with the 365 * zeroed icmp_void field. 366 */ 367 if (type == ICMP_PARAMPROB) { 368 icp->icmp_pptr = code; 369 code = 0; 370 } else if (type == ICMP_UNREACH && 371 code == ICMP_UNREACH_NEEDFRAG && destmtu) 372 icp->icmp_nextmtu = htons(destmtu); 373 } 374 icp->icmp_code = code; 375 m_copydata(n, 0, datalen, (void *)&icp->icmp_ip); 376 377 /* 378 * Come back to the IP header. 379 */ 380 if ((m->m_flags & M_EXT) == 0 && 381 m->m_data - sizeof(struct ip) < m->m_pktdat) 382 panic("icmp len"); 383 m->m_data -= sizeof(struct ip); 384 m->m_len += sizeof(struct ip); 385 m->m_pkthdr.len = m->m_len; 386 m_copy_rcvif(m, n); 387 388 /* 389 * Now, copy the old IP header (without options) in front of the 390 * ICMP message. The src/dst fields will be swapped in icmp_reflect. 391 */ 392 nip = mtod(m, struct ip *); 393 /* ip_v set in ip_output */ 394 nip->ip_hl = sizeof(struct ip) >> 2; 395 nip->ip_tos = 0; 396 nip->ip_len = htons(m->m_len); 397 /* ip_id set in ip_output */ 398 nip->ip_off = htons(0); 399 /* ip_ttl set in icmp_reflect */ 400 nip->ip_p = IPPROTO_ICMP; 401 nip->ip_src = oip->ip_src; 402 nip->ip_dst = oip->ip_dst; 403 /* move PF m_tag to new packet, if it exists */ 404 mtag = m_tag_find(n, PACKET_TAG_PF, NULL); 405 if (mtag != NULL) { 406 m_tag_unlink(n, mtag); 407 m_tag_prepend(m, mtag); 408 } 409 410 icmp_reflect(m); 411 412 freeit: 413 m_freem(n); 414 } 415 416 struct sockaddr_in icmpsrc = { 417 .sin_len = sizeof (struct sockaddr_in), 418 .sin_family = AF_INET, 419 }; 420 static struct sockaddr_in icmpdst = { 421 .sin_len = sizeof (struct sockaddr_in), 422 .sin_family = AF_INET, 423 }; 424 static struct sockaddr_in icmpgw = { 425 .sin_len = sizeof (struct sockaddr_in), 426 .sin_family = AF_INET, 427 }; 428 struct sockaddr_in icmpmask = { 429 .sin_len = 8, 430 .sin_family = 0, 431 }; 432 433 /* 434 * Process a received ICMP message. 435 */ 436 static void 437 _icmp_input(struct mbuf *m, int hlen, int proto) 438 { 439 struct icmp *icp; 440 struct ip *ip = mtod(m, struct ip *); 441 int icmplen; 442 int i; 443 struct in_ifaddr *ia; 444 void *(*ctlfunc)(int, const struct sockaddr *, void *); 445 int code; 446 struct rtentry *rt; 447 448 /* 449 * Locate icmp structure in mbuf, and check 450 * that not corrupted and of at least minimum length. 451 */ 452 icmplen = ntohs(ip->ip_len) - hlen; 453 #ifdef ICMPPRINTFS 454 if (icmpprintfs) { 455 char sbuf[INET_ADDRSTRLEN], dbuf[INET_ADDRSTRLEN]; 456 printf("icmp_input from `%s' to `%s', len %d\n", 457 IN_PRINT(sbuf, &ip->ip_src), IN_PRINT(dbuf, &ip->ip_dst), 458 icmplen); 459 } 460 #endif 461 if (icmplen < ICMP_MINLEN) { 462 ICMP_STATINC(ICMP_STAT_TOOSHORT); 463 goto freeit; 464 } 465 i = hlen + min(icmplen, ICMP_ADVLENMIN); 466 if ((m->m_len < i || M_READONLY(m)) && (m = m_pullup(m, i)) == NULL) { 467 ICMP_STATINC(ICMP_STAT_TOOSHORT); 468 return; 469 } 470 ip = mtod(m, struct ip *); 471 m->m_len -= hlen; 472 m->m_data += hlen; 473 icp = mtod(m, struct icmp *); 474 /* Don't need to assert alignment, here. */ 475 if (in_cksum(m, icmplen)) { 476 ICMP_STATINC(ICMP_STAT_CHECKSUM); 477 goto freeit; 478 } 479 m->m_len += hlen; 480 m->m_data -= hlen; 481 482 #ifdef ICMPPRINTFS 483 /* 484 * Message type specific processing. 485 */ 486 if (icmpprintfs) 487 printf("icmp_input(type:%d, code:%d)\n", icp->icmp_type, 488 icp->icmp_code); 489 #endif 490 if (icp->icmp_type > ICMP_MAXTYPE) 491 goto raw; 492 ICMP_STATINC(ICMP_STAT_INHIST + icp->icmp_type); 493 code = icp->icmp_code; 494 switch (icp->icmp_type) { 495 496 case ICMP_UNREACH: 497 switch (code) { 498 case ICMP_UNREACH_PROTOCOL: 499 code = PRC_UNREACH_PROTOCOL; 500 break; 501 502 case ICMP_UNREACH_PORT: 503 code = PRC_UNREACH_PORT; 504 break; 505 506 case ICMP_UNREACH_SRCFAIL: 507 code = PRC_UNREACH_SRCFAIL; 508 break; 509 510 case ICMP_UNREACH_NEEDFRAG: 511 code = PRC_MSGSIZE; 512 break; 513 514 case ICMP_UNREACH_NET: 515 case ICMP_UNREACH_NET_UNKNOWN: 516 case ICMP_UNREACH_NET_PROHIB: 517 case ICMP_UNREACH_TOSNET: 518 code = PRC_UNREACH_NET; 519 break; 520 521 case ICMP_UNREACH_HOST: 522 case ICMP_UNREACH_HOST_UNKNOWN: 523 case ICMP_UNREACH_ISOLATED: 524 case ICMP_UNREACH_HOST_PROHIB: 525 case ICMP_UNREACH_TOSHOST: 526 case ICMP_UNREACH_ADMIN_PROHIBIT: 527 case ICMP_UNREACH_HOST_PREC: 528 case ICMP_UNREACH_PREC_CUTOFF: 529 code = PRC_UNREACH_HOST; 530 break; 531 532 default: 533 goto badcode; 534 } 535 goto deliver; 536 537 case ICMP_TIMXCEED: 538 if (code > 1) 539 goto badcode; 540 code += PRC_TIMXCEED_INTRANS; 541 goto deliver; 542 543 case ICMP_PARAMPROB: 544 if (code > 1) 545 goto badcode; 546 code = PRC_PARAMPROB; 547 goto deliver; 548 549 case ICMP_SOURCEQUENCH: 550 if (code) 551 goto badcode; 552 code = PRC_QUENCH; 553 goto deliver; 554 555 deliver: 556 /* 557 * Problem with datagram; advise higher level routines. 558 */ 559 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 560 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 561 ICMP_STATINC(ICMP_STAT_BADLEN); 562 goto freeit; 563 } 564 if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr)) 565 goto badcode; 566 #ifdef ICMPPRINTFS 567 if (icmpprintfs) 568 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 569 #endif 570 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 571 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 572 if (ctlfunc) 573 (void) (*ctlfunc)(code, sintosa(&icmpsrc), 574 &icp->icmp_ip); 575 break; 576 577 badcode: 578 ICMP_STATINC(ICMP_STAT_BADCODE); 579 break; 580 581 case ICMP_ECHO: 582 if (!icmpbmcastecho && 583 (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 584 ICMP_STATINC(ICMP_STAT_BMCASTECHO); 585 break; 586 } 587 icp->icmp_type = ICMP_ECHOREPLY; 588 goto reflect; 589 590 case ICMP_TSTAMP: 591 if (icmplen < ICMP_TSLEN) { 592 ICMP_STATINC(ICMP_STAT_BADLEN); 593 break; 594 } 595 if (!icmpbmcastecho && 596 (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 597 ICMP_STATINC(ICMP_STAT_BMCASTTSTAMP); 598 break; 599 } 600 icp->icmp_type = ICMP_TSTAMPREPLY; 601 icp->icmp_rtime = iptime(); 602 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 603 goto reflect; 604 605 case ICMP_MASKREQ: { 606 struct ifnet *rcvif; 607 int s, ss; 608 struct ifaddr *ifa = NULL; 609 610 if (icmpmaskrepl == 0) 611 break; 612 /* 613 * We are not able to respond with all ones broadcast 614 * unless we receive it over a point-to-point interface. 615 */ 616 if (icmplen < ICMP_MASKLEN) { 617 ICMP_STATINC(ICMP_STAT_BADLEN); 618 break; 619 } 620 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 621 in_nullhost(ip->ip_dst)) 622 icmpdst.sin_addr = ip->ip_src; 623 else 624 icmpdst.sin_addr = ip->ip_dst; 625 ss = pserialize_read_enter(); 626 rcvif = m_get_rcvif(m, &s); 627 if (__predict_true(rcvif != NULL)) 628 ifa = ifaof_ifpforaddr(sintosa(&icmpdst), rcvif); 629 m_put_rcvif(rcvif, &s); 630 if (ifa == NULL) { 631 pserialize_read_exit(ss); 632 break; 633 } 634 ia = ifatoia(ifa); 635 icp->icmp_type = ICMP_MASKREPLY; 636 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 637 if (in_nullhost(ip->ip_src)) { 638 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 639 ip->ip_src = ia->ia_broadaddr.sin_addr; 640 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 641 ip->ip_src = ia->ia_dstaddr.sin_addr; 642 } 643 pserialize_read_exit(ss); 644 reflect: 645 { 646 uint64_t *icps = percpu_getref(icmpstat_percpu); 647 icps[ICMP_STAT_REFLECT]++; 648 icps[ICMP_STAT_OUTHIST + icp->icmp_type]++; 649 percpu_putref(icmpstat_percpu); 650 } 651 icmp_reflect(m); 652 return; 653 } 654 655 case ICMP_REDIRECT: 656 if (code > 3) 657 goto badcode; 658 if (icmp_rediraccept == 0) 659 goto freeit; 660 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 661 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 662 ICMP_STATINC(ICMP_STAT_BADLEN); 663 break; 664 } 665 /* 666 * Short circuit routing redirects to force 667 * immediate change in the kernel's routing 668 * tables. The message is also handed to anyone 669 * listening on a raw socket (e.g. the routing 670 * daemon for use in updating its tables). 671 */ 672 icmpgw.sin_addr = ip->ip_src; 673 icmpdst.sin_addr = icp->icmp_gwaddr; 674 #ifdef ICMPPRINTFS 675 if (icmpprintfs) { 676 char gbuf[INET_ADDRSTRLEN], dbuf[INET_ADDRSTRLEN]; 677 printf("redirect dst `%s' to `%s'\n", 678 IN_PRINT(dbuf, &icp->icmp_ip.ip_dst), 679 IN_PRINT(gbuf, &icp->icmp_gwaddr)); 680 } 681 #endif 682 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 683 rt = NULL; 684 rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst), 685 NULL, RTF_GATEWAY | RTF_HOST, sintosa(&icmpgw), &rt); 686 mutex_enter(&icmp_mtx); 687 if (rt != NULL && icmp_redirtimeout != 0) { 688 i = rt_timer_add(rt, icmp_redirect_timeout, 689 icmp_redirect_timeout_q); 690 if (i) { 691 char buf[INET_ADDRSTRLEN]; 692 log(LOG_ERR, "ICMP: redirect failed to " 693 "register timeout for route to %s, " 694 "code %d\n", 695 IN_PRINT(buf, &icp->icmp_ip.ip_dst), i); 696 } 697 } 698 mutex_exit(&icmp_mtx); 699 if (rt != NULL) 700 rt_unref(rt); 701 702 pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc)); 703 #if defined(IPSEC) 704 if (ipsec_used) 705 key_sa_routechange((struct sockaddr *)&icmpsrc); 706 #endif 707 break; 708 709 /* 710 * No kernel processing for the following; 711 * just fall through to send to raw listener. 712 */ 713 case ICMP_ECHOREPLY: 714 case ICMP_ROUTERADVERT: 715 case ICMP_ROUTERSOLICIT: 716 case ICMP_TSTAMPREPLY: 717 case ICMP_IREQREPLY: 718 case ICMP_MASKREPLY: 719 default: 720 break; 721 } 722 723 raw: 724 rip_input(m, hlen, proto); 725 return; 726 727 freeit: 728 m_freem(m); 729 return; 730 } 731 732 void 733 icmp_input(struct mbuf *m, ...) 734 { 735 int hlen, proto; 736 va_list ap; 737 738 va_start(ap, m); 739 hlen = va_arg(ap, int); 740 proto = va_arg(ap, int); 741 va_end(ap); 742 743 wqinput_input(icmp_wqinput, m, hlen, proto); 744 } 745 746 /* 747 * Reflect the ip packet back to the source 748 */ 749 void 750 icmp_reflect(struct mbuf *m) 751 { 752 struct ip *ip = mtod(m, struct ip *); 753 struct in_ifaddr *ia; 754 struct ifaddr *ifa; 755 struct sockaddr_in *sin; 756 struct in_addr t; 757 struct mbuf *opts = NULL; 758 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 759 struct ifnet *rcvif; 760 struct psref psref, psref_ia; 761 int s; 762 int bound; 763 764 bound = curlwp_bind(); 765 766 if (!in_canforward(ip->ip_src) && 767 ((ip->ip_src.s_addr & IN_CLASSA_NET) != 768 htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 769 m_freem(m); /* Bad return address */ 770 goto done; /* ip_output() will check for broadcast */ 771 } 772 t = ip->ip_dst; 773 ip->ip_dst = ip->ip_src; 774 /* 775 * If the incoming packet was addressed directly to us, use 776 * dst as the src for the reply. Otherwise (broadcast or 777 * anonymous), use an address which corresponds to the 778 * incoming interface, with a preference for the address which 779 * corresponds to the route to the destination of the ICMP. 780 */ 781 782 /* Look for packet addressed to us */ 783 ia = in_get_ia_psref(t, &psref_ia); 784 if (ia && (ia->ia4_flags & IN_IFF_NOTREADY)) { 785 ia4_release(ia, &psref_ia); 786 ia = NULL; 787 } 788 789 rcvif = m_get_rcvif_psref(m, &psref); 790 791 /* look for packet sent to broadcast address */ 792 if (ia == NULL && rcvif && 793 (rcvif->if_flags & IFF_BROADCAST)) { 794 s = pserialize_read_enter(); 795 IFADDR_READER_FOREACH(ifa, rcvif) { 796 if (ifa->ifa_addr->sa_family != AF_INET) 797 continue; 798 if (in_hosteq(t,ifatoia(ifa)->ia_broadaddr.sin_addr)) { 799 ia = ifatoia(ifa); 800 if ((ia->ia4_flags & IN_IFF_NOTREADY) == 0) 801 break; 802 ia = NULL; 803 } 804 } 805 if (ia != NULL) 806 ia4_acquire(ia, &psref_ia); 807 pserialize_read_exit(s); 808 } 809 810 sin = ia ? &ia->ia_addr : NULL; 811 812 icmpdst.sin_addr = t; 813 814 /* 815 * if the packet is addressed somewhere else, compute the 816 * source address for packets routed back to the source, and 817 * use that, if it's an address on the interface which 818 * received the packet 819 */ 820 if (sin == NULL && rcvif) { 821 struct sockaddr_in sin_dst; 822 struct route icmproute; 823 int errornum; 824 825 sockaddr_in_init(&sin_dst, &ip->ip_dst, 0); 826 memset(&icmproute, 0, sizeof(icmproute)); 827 errornum = 0; 828 ia = in_selectsrc(&sin_dst, &icmproute, 0, NULL, &errornum, 829 &psref_ia); 830 /* errornum is never used */ 831 rtcache_free(&icmproute); 832 /* check to make sure sin is a source address on rcvif */ 833 if (ia != NULL) { 834 sin = &ia->ia_addr; 835 t = sin->sin_addr; 836 sin = NULL; 837 ia4_release(ia, &psref_ia); 838 ia = in_get_ia_on_iface_psref(t, rcvif, &psref_ia); 839 if (ia != NULL) 840 sin = &ia->ia_addr; 841 } 842 } 843 844 /* 845 * if it was not addressed to us, but the route doesn't go out 846 * the source interface, pick an address on the source 847 * interface. This can happen when routing is asymmetric, or 848 * when the incoming packet was encapsulated 849 */ 850 if (sin == NULL && rcvif) { 851 KASSERT(ia == NULL); 852 s = pserialize_read_enter(); 853 IFADDR_READER_FOREACH(ifa, rcvif) { 854 if (ifa->ifa_addr->sa_family != AF_INET) 855 continue; 856 sin = &(ifatoia(ifa)->ia_addr); 857 ia = ifatoia(ifa); 858 ia4_acquire(ia, &psref_ia); 859 break; 860 } 861 pserialize_read_exit(s); 862 } 863 864 m_put_rcvif_psref(rcvif, &psref); 865 866 /* 867 * The following happens if the packet was not addressed to us, 868 * and was received on an interface with no IP address: 869 * We find the first AF_INET address on the first non-loopback 870 * interface. 871 */ 872 if (sin == NULL) { 873 KASSERT(ia == NULL); 874 s = pserialize_read_enter(); 875 IN_ADDRLIST_READER_FOREACH(ia) { 876 if (ia->ia_ifp->if_flags & IFF_LOOPBACK) 877 continue; 878 sin = &ia->ia_addr; 879 ia4_acquire(ia, &psref_ia); 880 break; 881 } 882 pserialize_read_exit(s); 883 } 884 885 /* 886 * If we still didn't find an address, punt. We could have an 887 * interface up (and receiving packets) with no address. 888 */ 889 if (sin == NULL) { 890 KASSERT(ia == NULL); 891 m_freem(m); 892 goto done; 893 } 894 895 ip->ip_src = sin->sin_addr; 896 ip->ip_ttl = MAXTTL; 897 898 if (ia != NULL) 899 ia4_release(ia, &psref_ia); 900 901 if (optlen > 0) { 902 u_char *cp; 903 int opt, cnt; 904 u_int len; 905 906 /* 907 * Retrieve any source routing from the incoming packet; 908 * add on any record-route or timestamp options. 909 */ 910 cp = (u_char *) (ip + 1); 911 if ((opts = ip_srcroute(m)) == NULL && 912 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 913 MCLAIM(opts, m->m_owner); 914 opts->m_len = sizeof(struct in_addr); 915 *mtod(opts, struct in_addr *) = zeroin_addr; 916 } 917 if (opts) { 918 #ifdef ICMPPRINTFS 919 if (icmpprintfs) 920 printf("icmp_reflect optlen %d rt %d => ", 921 optlen, opts->m_len); 922 #endif 923 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 924 opt = cp[IPOPT_OPTVAL]; 925 if (opt == IPOPT_EOL) 926 break; 927 if (opt == IPOPT_NOP) 928 len = 1; 929 else { 930 if (cnt < IPOPT_OLEN + sizeof(*cp)) 931 break; 932 len = cp[IPOPT_OLEN]; 933 if (len < IPOPT_OLEN + sizeof(*cp) || 934 len > cnt) 935 break; 936 } 937 /* 938 * Should check for overflow, but it "can't happen" 939 */ 940 if (opt == IPOPT_RR || opt == IPOPT_TS || 941 opt == IPOPT_SECURITY) { 942 memmove(mtod(opts, char *) + opts->m_len, 943 cp, len); 944 opts->m_len += len; 945 } 946 } 947 /* Terminate & pad, if necessary */ 948 if ((cnt = opts->m_len % 4) != 0) { 949 for (; cnt < 4; cnt++) { 950 *(mtod(opts, char *) + opts->m_len) = 951 IPOPT_EOL; 952 opts->m_len++; 953 } 954 } 955 #ifdef ICMPPRINTFS 956 if (icmpprintfs) 957 printf("%d\n", opts->m_len); 958 #endif 959 } 960 /* 961 * Now strip out original options by copying rest of first 962 * mbuf's data back, and adjust the IP length. 963 */ 964 ip->ip_len = htons(ntohs(ip->ip_len) - optlen); 965 ip->ip_hl = sizeof(struct ip) >> 2; 966 m->m_len -= optlen; 967 if (m->m_flags & M_PKTHDR) 968 m->m_pkthdr.len -= optlen; 969 optlen += sizeof(struct ip); 970 memmove(ip + 1, (char *)ip + optlen, 971 (unsigned)(m->m_len - sizeof(struct ip))); 972 } 973 m_tag_delete_nonpersistent(m); 974 m->m_flags &= ~(M_BCAST|M_MCAST); 975 976 /* 977 * Clear any in-bound checksum flags for this packet. 978 */ 979 if (m->m_flags & M_PKTHDR) 980 m->m_pkthdr.csum_flags = 0; 981 982 icmp_send(m, opts); 983 done: 984 curlwp_bindx(bound); 985 if (opts) 986 (void)m_free(opts); 987 } 988 989 /* 990 * Send an icmp packet back to the ip level, 991 * after supplying a checksum. 992 */ 993 void 994 icmp_send(struct mbuf *m, struct mbuf *opts) 995 { 996 struct ip *ip = mtod(m, struct ip *); 997 int hlen; 998 struct icmp *icp; 999 1000 hlen = ip->ip_hl << 2; 1001 m->m_data += hlen; 1002 m->m_len -= hlen; 1003 icp = mtod(m, struct icmp *); 1004 icp->icmp_cksum = 0; 1005 icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen); 1006 m->m_data -= hlen; 1007 m->m_len += hlen; 1008 #ifdef ICMPPRINTFS 1009 if (icmpprintfs) { 1010 char sbuf[INET_ADDRSTRLEN], dbuf[INET_ADDRSTRLEN]; 1011 printf("icmp_send to destination `%s' from `%s'\n", 1012 IN_PRINT(dbuf, &ip->ip_dst), IN_PRINT(sbuf, &ip->ip_src)); 1013 } 1014 #endif 1015 (void)ip_output(m, opts, NULL, 0, NULL, NULL); 1016 } 1017 1018 n_time 1019 iptime(void) 1020 { 1021 struct timeval atv; 1022 u_long t; 1023 1024 microtime(&atv); 1025 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 1026 return (htonl(t)); 1027 } 1028 1029 /* 1030 * sysctl helper routine for net.inet.icmp.returndatabytes. ensures 1031 * that the new value is in the correct range. 1032 */ 1033 static int 1034 sysctl_net_inet_icmp_returndatabytes(SYSCTLFN_ARGS) 1035 { 1036 int error, t; 1037 struct sysctlnode node; 1038 1039 node = *rnode; 1040 node.sysctl_data = &t; 1041 t = icmpreturndatabytes; 1042 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1043 if (error || newp == NULL) 1044 return (error); 1045 1046 if (t < 8 || t > 512) 1047 return (EINVAL); 1048 icmpreturndatabytes = t; 1049 1050 return (0); 1051 } 1052 1053 /* 1054 * sysctl helper routine for net.inet.icmp.redirtimeout. ensures that 1055 * the given value is not less than zero and then resets the timeout 1056 * queue. 1057 */ 1058 static int 1059 sysctl_net_inet_icmp_redirtimeout(SYSCTLFN_ARGS) 1060 { 1061 int error, tmp; 1062 struct sysctlnode node; 1063 1064 mutex_enter(&icmp_mtx); 1065 1066 node = *rnode; 1067 node.sysctl_data = &tmp; 1068 tmp = icmp_redirtimeout; 1069 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1070 if (error || newp == NULL) 1071 goto out; 1072 if (tmp < 0) { 1073 error = EINVAL; 1074 goto out; 1075 } 1076 icmp_redirtimeout = tmp; 1077 1078 /* 1079 * was it a *defined* side-effect that anyone even *reading* 1080 * this value causes these things to happen? 1081 */ 1082 if (icmp_redirect_timeout_q != NULL) { 1083 if (icmp_redirtimeout == 0) { 1084 rt_timer_queue_destroy(icmp_redirect_timeout_q); 1085 icmp_redirect_timeout_q = NULL; 1086 } else { 1087 rt_timer_queue_change(icmp_redirect_timeout_q, 1088 icmp_redirtimeout); 1089 } 1090 } else if (icmp_redirtimeout > 0) { 1091 icmp_redirect_timeout_q = 1092 rt_timer_queue_create(icmp_redirtimeout); 1093 } 1094 error = 0; 1095 out: 1096 mutex_exit(&icmp_mtx); 1097 return error; 1098 } 1099 1100 static int 1101 sysctl_net_inet_icmp_stats(SYSCTLFN_ARGS) 1102 { 1103 1104 return (NETSTAT_SYSCTL(icmpstat_percpu, ICMP_NSTATS)); 1105 } 1106 1107 static void 1108 sysctl_netinet_icmp_setup(struct sysctllog **clog) 1109 { 1110 1111 sysctl_createv(clog, 0, NULL, NULL, 1112 CTLFLAG_PERMANENT, 1113 CTLTYPE_NODE, "inet", NULL, 1114 NULL, 0, NULL, 0, 1115 CTL_NET, PF_INET, CTL_EOL); 1116 sysctl_createv(clog, 0, NULL, NULL, 1117 CTLFLAG_PERMANENT, 1118 CTLTYPE_NODE, "icmp", 1119 SYSCTL_DESCR("ICMPv4 related settings"), 1120 NULL, 0, NULL, 0, 1121 CTL_NET, PF_INET, IPPROTO_ICMP, CTL_EOL); 1122 1123 sysctl_createv(clog, 0, NULL, NULL, 1124 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1125 CTLTYPE_INT, "maskrepl", 1126 SYSCTL_DESCR("Respond to ICMP_MASKREQ messages"), 1127 NULL, 0, &icmpmaskrepl, 0, 1128 CTL_NET, PF_INET, IPPROTO_ICMP, 1129 ICMPCTL_MASKREPL, CTL_EOL); 1130 sysctl_createv(clog, 0, NULL, NULL, 1131 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1132 CTLTYPE_INT, "returndatabytes", 1133 SYSCTL_DESCR("Number of bytes to return in an ICMP " 1134 "error message"), 1135 sysctl_net_inet_icmp_returndatabytes, 0, 1136 &icmpreturndatabytes, 0, 1137 CTL_NET, PF_INET, IPPROTO_ICMP, 1138 ICMPCTL_RETURNDATABYTES, CTL_EOL); 1139 sysctl_createv(clog, 0, NULL, NULL, 1140 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1141 CTLTYPE_INT, "errppslimit", 1142 SYSCTL_DESCR("Maximum number of outgoing ICMP error " 1143 "messages per second"), 1144 NULL, 0, &icmperrppslim, 0, 1145 CTL_NET, PF_INET, IPPROTO_ICMP, 1146 ICMPCTL_ERRPPSLIMIT, CTL_EOL); 1147 sysctl_createv(clog, 0, NULL, NULL, 1148 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1149 CTLTYPE_INT, "rediraccept", 1150 SYSCTL_DESCR("Accept ICMP_REDIRECT messages"), 1151 NULL, 0, &icmp_rediraccept, 0, 1152 CTL_NET, PF_INET, IPPROTO_ICMP, 1153 ICMPCTL_REDIRACCEPT, CTL_EOL); 1154 sysctl_createv(clog, 0, NULL, NULL, 1155 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1156 CTLTYPE_INT, "redirtimeout", 1157 SYSCTL_DESCR("Lifetime of ICMP_REDIRECT generated " 1158 "routes"), 1159 sysctl_net_inet_icmp_redirtimeout, 0, 1160 &icmp_redirtimeout, 0, 1161 CTL_NET, PF_INET, IPPROTO_ICMP, 1162 ICMPCTL_REDIRTIMEOUT, CTL_EOL); 1163 sysctl_createv(clog, 0, NULL, NULL, 1164 CTLFLAG_PERMANENT, 1165 CTLTYPE_STRUCT, "stats", 1166 SYSCTL_DESCR("ICMP statistics"), 1167 sysctl_net_inet_icmp_stats, 0, NULL, 0, 1168 CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_STATS, 1169 CTL_EOL); 1170 sysctl_createv(clog, 0, NULL, NULL, 1171 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1172 CTLTYPE_INT, "bmcastecho", 1173 SYSCTL_DESCR("Respond to ICMP_ECHO or ICMP_TIMESTAMP " 1174 "message to the broadcast or multicast"), 1175 NULL, 0, &icmpbmcastecho, 0, 1176 CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_BMCASTECHO, 1177 CTL_EOL); 1178 } 1179 1180 void 1181 icmp_statinc(u_int stat) 1182 { 1183 1184 KASSERT(stat < ICMP_NSTATS); 1185 ICMP_STATINC(stat); 1186 } 1187 1188 /* Table of common MTUs: */ 1189 1190 static const u_int mtu_table[] = { 1191 65535, 65280, 32000, 17914, 9180, 8166, 1192 4352, 2002, 1492, 1006, 508, 296, 68, 0 1193 }; 1194 1195 void 1196 icmp_mtudisc(struct icmp *icp, struct in_addr faddr) 1197 { 1198 struct icmp_mtudisc_callback *mc; 1199 struct sockaddr *dst = sintosa(&icmpsrc); 1200 struct rtentry *rt; 1201 u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */ 1202 int error; 1203 1204 rt = rtalloc1(dst, 1); 1205 if (rt == NULL) 1206 return; 1207 1208 /* If we didn't get a host route, allocate one */ 1209 1210 if ((rt->rt_flags & RTF_HOST) == 0) { 1211 struct rtentry *nrt; 1212 1213 error = rtrequest(RTM_ADD, dst, rt->rt_gateway, NULL, 1214 RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt); 1215 if (error) { 1216 rt_unref(rt); 1217 return; 1218 } 1219 nrt->rt_rmx = rt->rt_rmx; 1220 rt_unref(rt); 1221 rt = nrt; 1222 } 1223 1224 mutex_enter(&icmp_mtx); 1225 error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q); 1226 mutex_exit(&icmp_mtx); 1227 if (error) { 1228 rt_unref(rt); 1229 return; 1230 } 1231 1232 if (mtu == 0) { 1233 int i = 0; 1234 1235 mtu = ntohs(icp->icmp_ip.ip_len); 1236 /* Some 4.2BSD-based routers incorrectly adjust the ip_len */ 1237 if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0) 1238 mtu -= (icp->icmp_ip.ip_hl << 2); 1239 1240 /* If we still can't guess a value, try the route */ 1241 1242 if (mtu == 0) { 1243 mtu = rt->rt_rmx.rmx_mtu; 1244 1245 /* If no route mtu, default to the interface mtu */ 1246 1247 if (mtu == 0) 1248 mtu = rt->rt_ifp->if_mtu; 1249 } 1250 1251 for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++) 1252 if (mtu > mtu_table[i]) { 1253 mtu = mtu_table[i]; 1254 break; 1255 } 1256 } 1257 1258 /* 1259 * XXX: RTV_MTU is overloaded, since the admin can set it 1260 * to turn off PMTU for a route, and the kernel can 1261 * set it to indicate a serious problem with PMTU 1262 * on a route. We should be using a separate flag 1263 * for the kernel to indicate this. 1264 */ 1265 1266 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 1267 if (mtu < 296 || mtu > rt->rt_ifp->if_mtu) 1268 rt->rt_rmx.rmx_locks |= RTV_MTU; 1269 else if (rt->rt_rmx.rmx_mtu > mtu || 1270 rt->rt_rmx.rmx_mtu == 0) { 1271 ICMP_STATINC(ICMP_STAT_PMTUCHG); 1272 rt->rt_rmx.rmx_mtu = mtu; 1273 } 1274 } 1275 1276 if (rt != NULL) 1277 rt_unref(rt); 1278 1279 /* 1280 * Notify protocols that the MTU for this destination 1281 * has changed. 1282 */ 1283 mutex_enter(&icmp_mtx); 1284 for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL; 1285 mc = LIST_NEXT(mc, mc_list)) 1286 (*mc->mc_func)(faddr); 1287 mutex_exit(&icmp_mtx); 1288 } 1289 1290 /* 1291 * Return the next larger or smaller MTU plateau (table from RFC 1191) 1292 * given current value MTU. If DIR is less than zero, a larger plateau 1293 * is returned; otherwise, a smaller value is returned. 1294 */ 1295 u_int 1296 ip_next_mtu(u_int mtu, int dir) /* XXX */ 1297 { 1298 int i; 1299 1300 for (i = 0; i < (sizeof mtu_table) / (sizeof mtu_table[0]); i++) { 1301 if (mtu >= mtu_table[i]) 1302 break; 1303 } 1304 1305 if (dir < 0) { 1306 if (i == 0) { 1307 return 0; 1308 } else { 1309 return mtu_table[i - 1]; 1310 } 1311 } else { 1312 if (mtu_table[i] == 0) { 1313 return 0; 1314 } else if (mtu > mtu_table[i]) { 1315 return mtu_table[i]; 1316 } else { 1317 return mtu_table[i + 1]; 1318 } 1319 } 1320 } 1321 1322 static void 1323 icmp_mtudisc_timeout(struct rtentry *rt, struct rttimer *r) 1324 { 1325 1326 KASSERT(rt != NULL); 1327 rt_assert_referenced(rt); 1328 1329 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 1330 (RTF_DYNAMIC | RTF_HOST)) { 1331 rtrequest(RTM_DELETE, rt_getkey(rt), 1332 rt->rt_gateway, rt_mask(rt), rt->rt_flags, NULL); 1333 } else { 1334 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 1335 rt->rt_rmx.rmx_mtu = 0; 1336 } 1337 } 1338 } 1339 1340 static void 1341 icmp_redirect_timeout(struct rtentry *rt, struct rttimer *r) 1342 { 1343 1344 KASSERT(rt != NULL); 1345 rt_assert_referenced(rt); 1346 1347 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 1348 (RTF_DYNAMIC | RTF_HOST)) { 1349 rtrequest(RTM_DELETE, rt_getkey(rt), 1350 rt->rt_gateway, rt_mask(rt), rt->rt_flags, NULL); 1351 } 1352 } 1353 1354 /* 1355 * Perform rate limit check. 1356 * Returns 0 if it is okay to send the icmp packet. 1357 * Returns 1 if the router SHOULD NOT send this icmp packet due to rate 1358 * limitation. 1359 * 1360 * XXX per-destination/type check necessary? 1361 */ 1362 int 1363 icmp_ratelimit(const struct in_addr *dst, const int type, 1364 const int code) 1365 { 1366 1367 /* PPS limit */ 1368 if (!ppsratecheck(&icmperrppslim_last, &icmperrpps_count, 1369 icmperrppslim)) { 1370 /* The packet is subject to rate limit */ 1371 return 1; 1372 } 1373 1374 /* okay to send */ 1375 return 0; 1376 } 1377
Indexes created Thu Sep 25 16:09:42 GMT 2025