1 /* $NetBSD: ip_icmp.c,v 1.125 2011/07/17 20:54:53 joerg 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 1.125 2011/07/17 20:54:53 joerg Exp $"); 98 99 #include "opt_ipsec.h" 100 101 #include <sys/param.h> 102 #include <sys/systm.h> 103 #include <sys/malloc.h> 104 #include <sys/mbuf.h> 105 #include <sys/protosw.h> 106 #include <sys/socket.h> 107 #include <sys/time.h> 108 #include <sys/kernel.h> 109 #include <sys/syslog.h> 110 #include <sys/sysctl.h> 111 112 #include <net/if.h> 113 #include <net/route.h> 114 115 #include <netinet/in.h> 116 #include <netinet/in_systm.h> 117 #include <netinet/in_var.h> 118 #include <netinet/ip.h> 119 #include <netinet/ip_icmp.h> 120 #include <netinet/ip_var.h> 121 #include <netinet/in_pcb.h> 122 #include <netinet/in_proto.h> 123 #include <netinet/icmp_var.h> 124 #include <netinet/icmp_private.h> 125 126 #ifdef IPSEC 127 #include <netinet6/ipsec.h> 128 #include <netkey/key.h> 129 #endif 130 131 #ifdef FAST_IPSEC 132 #include <netipsec/ipsec.h> 133 #include <netipsec/key.h> 134 #endif /* FAST_IPSEC*/ 135 136 /* 137 * ICMP routines: error generation, receive packet processing, and 138 * routines to turnaround packets back to the originator, and 139 * host table maintenance routines. 140 */ 141 142 int icmpmaskrepl = 0; 143 int icmpbmcastecho = 0; 144 #ifdef ICMPPRINTFS 145 int icmpprintfs = 0; 146 #endif 147 int icmpreturndatabytes = 8; 148 149 percpu_t *icmpstat_percpu; 150 151 /* 152 * List of callbacks to notify when Path MTU changes are made. 153 */ 154 struct icmp_mtudisc_callback { 155 LIST_ENTRY(icmp_mtudisc_callback) mc_list; 156 void (*mc_func)(struct in_addr); 157 }; 158 159 LIST_HEAD(, icmp_mtudisc_callback) icmp_mtudisc_callbacks = 160 LIST_HEAD_INITIALIZER(&icmp_mtudisc_callbacks); 161 162 #if 0 163 static u_int ip_next_mtu(u_int, int); 164 #else 165 /*static*/ u_int ip_next_mtu(u_int, int); 166 #endif 167 168 extern int icmperrppslim; 169 static int icmperrpps_count = 0; 170 static struct timeval icmperrppslim_last; 171 static int icmp_rediraccept = 1; 172 static int icmp_redirtimeout = 600; 173 static struct rttimer_queue *icmp_redirect_timeout_q = NULL; 174 175 static void icmp_mtudisc_timeout(struct rtentry *, struct rttimer *); 176 static void icmp_redirect_timeout(struct rtentry *, struct rttimer *); 177 178 static void sysctl_netinet_icmp_setup(struct sysctllog **); 179 180 void 181 icmp_init(void) 182 { 183 184 sysctl_netinet_icmp_setup(NULL); 185 186 /* 187 * This is only useful if the user initializes redirtimeout to 188 * something other than zero. 189 */ 190 if (icmp_redirtimeout != 0) { 191 icmp_redirect_timeout_q = 192 rt_timer_queue_create(icmp_redirtimeout); 193 } 194 195 icmpstat_percpu = percpu_alloc(sizeof(uint64_t) * ICMP_NSTATS); 196 } 197 198 /* 199 * Register a Path MTU Discovery callback. 200 */ 201 void 202 icmp_mtudisc_callback_register(void (*func)(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(struct mbuf *n, int type, int code, n_long dest, 226 int destmtu) 227 { 228 struct ip *oip = mtod(n, struct ip *), *nip; 229 unsigned oiplen = oip->ip_hl << 2; 230 struct icmp *icp; 231 struct mbuf *m; 232 struct m_tag *mtag; 233 unsigned icmplen, mblen; 234 235 #ifdef ICMPPRINTFS 236 if (icmpprintfs) 237 printf("icmp_error(%p, type:%d, code:%d)\n", oip, type, code); 238 #endif 239 if (type != ICMP_REDIRECT) 240 ICMP_STATINC(ICMP_STAT_ERROR); 241 /* 242 * Don't send error if the original packet was encrypted. 243 * Don't send error if not the first fragment of message. 244 * Don't error if the old packet protocol was ICMP 245 * error message, only known informational types. 246 */ 247 if (n->m_flags & M_DECRYPTED) 248 goto freeit; 249 if (oip->ip_off &~ htons(IP_MF|IP_DF)) 250 goto freeit; 251 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 252 n->m_len >= oiplen + ICMP_MINLEN && 253 !ICMP_INFOTYPE(((struct icmp *)((char *)oip + oiplen))->icmp_type)) { 254 ICMP_STATINC(ICMP_STAT_OLDICMP); 255 goto freeit; 256 } 257 /* Don't send error in response to a multicast or broadcast packet */ 258 if (n->m_flags & (M_BCAST|M_MCAST)) 259 goto freeit; 260 261 /* 262 * First, do a rate limitation check. 263 */ 264 if (icmp_ratelimit(&oip->ip_src, type, code)) { 265 /* XXX stat */ 266 goto freeit; 267 } 268 269 /* 270 * Now, formulate icmp message 271 */ 272 icmplen = oiplen + min(icmpreturndatabytes, 273 ntohs(oip->ip_len) - oiplen); 274 /* 275 * Defend against mbuf chains shorter than oip->ip_len - oiplen: 276 */ 277 mblen = 0; 278 for (m = n; m && (mblen < icmplen); m = m->m_next) 279 mblen += m->m_len; 280 icmplen = min(mblen, icmplen); 281 282 /* 283 * As we are not required to return everything we have, 284 * we return whatever we can return at ease. 285 * 286 * Note that ICMP datagrams longer than 576 octets are out of spec 287 * according to RFC1812; the limit on icmpreturndatabytes below in 288 * icmp_sysctl will keep things below that limit. 289 */ 290 291 KASSERT(ICMP_MINLEN <= MCLBYTES); 292 293 if (icmplen + ICMP_MINLEN > MCLBYTES) 294 icmplen = MCLBYTES - ICMP_MINLEN; 295 296 m = m_gethdr(M_DONTWAIT, MT_HEADER); 297 if (m && (icmplen + ICMP_MINLEN > MHLEN)) { 298 MCLGET(m, M_DONTWAIT); 299 if ((m->m_flags & M_EXT) == 0) { 300 m_freem(m); 301 m = NULL; 302 } 303 } 304 if (m == NULL) 305 goto freeit; 306 MCLAIM(m, n->m_owner); 307 m->m_len = icmplen + ICMP_MINLEN; 308 if ((m->m_flags & M_EXT) == 0) 309 MH_ALIGN(m, m->m_len); 310 else { 311 m->m_data += sizeof(struct ip); 312 m->m_len -= sizeof(struct ip); 313 } 314 icp = mtod(m, struct icmp *); 315 if ((u_int)type > ICMP_MAXTYPE) 316 panic("icmp_error"); 317 ICMP_STATINC(ICMP_STAT_OUTHIST + type); 318 icp->icmp_type = type; 319 if (type == ICMP_REDIRECT) 320 icp->icmp_gwaddr.s_addr = dest; 321 else { 322 icp->icmp_void = 0; 323 /* 324 * The following assignments assume an overlay with the 325 * zeroed icmp_void field. 326 */ 327 if (type == ICMP_PARAMPROB) { 328 icp->icmp_pptr = code; 329 code = 0; 330 } else if (type == ICMP_UNREACH && 331 code == ICMP_UNREACH_NEEDFRAG && destmtu) 332 icp->icmp_nextmtu = htons(destmtu); 333 } 334 335 icp->icmp_code = code; 336 m_copydata(n, 0, icmplen, (void *)&icp->icmp_ip); 337 338 /* 339 * Now, copy old ip header (without options) 340 * in front of icmp message. 341 */ 342 if ((m->m_flags & M_EXT) == 0 && 343 m->m_data - sizeof(struct ip) < m->m_pktdat) 344 panic("icmp len"); 345 m->m_data -= sizeof(struct ip); 346 m->m_len += sizeof(struct ip); 347 m->m_pkthdr.len = m->m_len; 348 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 349 nip = mtod(m, struct ip *); 350 /* ip_v set in ip_output */ 351 nip->ip_hl = sizeof(struct ip) >> 2; 352 nip->ip_tos = 0; 353 nip->ip_len = htons(m->m_len); 354 /* ip_id set in ip_output */ 355 nip->ip_off = htons(0); 356 /* ip_ttl set in icmp_reflect */ 357 nip->ip_p = IPPROTO_ICMP; 358 nip->ip_src = oip->ip_src; 359 nip->ip_dst = oip->ip_dst; 360 /* move PF m_tag to new packet, if it exists */ 361 mtag = m_tag_find(n, PACKET_TAG_PF, NULL); 362 if (mtag != NULL) { 363 m_tag_unlink(n, mtag); 364 m_tag_prepend(m, mtag); 365 } 366 icmp_reflect(m); 367 368 freeit: 369 m_freem(n); 370 } 371 372 struct sockaddr_in icmpsrc = { 373 .sin_len = sizeof (struct sockaddr_in), 374 .sin_family = AF_INET, 375 }; 376 static struct sockaddr_in icmpdst = { 377 .sin_len = sizeof (struct sockaddr_in), 378 .sin_family = AF_INET, 379 }; 380 static struct sockaddr_in icmpgw = { 381 .sin_len = sizeof (struct sockaddr_in), 382 .sin_family = AF_INET, 383 }; 384 struct sockaddr_in icmpmask = { 385 .sin_len = 8, 386 .sin_family = 0, 387 }; 388 389 /* 390 * Process a received ICMP message. 391 */ 392 void 393 icmp_input(struct mbuf *m, ...) 394 { 395 int proto; 396 struct icmp *icp; 397 struct ip *ip = mtod(m, struct ip *); 398 int icmplen; 399 int i; 400 struct in_ifaddr *ia; 401 void *(*ctlfunc)(int, const struct sockaddr *, void *); 402 int code; 403 int hlen; 404 va_list ap; 405 struct rtentry *rt; 406 407 va_start(ap, m); 408 hlen = va_arg(ap, int); 409 proto = va_arg(ap, int); 410 va_end(ap); 411 412 /* 413 * Locate icmp structure in mbuf, and check 414 * that not corrupted and of at least minimum length. 415 */ 416 icmplen = ntohs(ip->ip_len) - hlen; 417 #ifdef ICMPPRINTFS 418 if (icmpprintfs) { 419 printf("icmp_input from `%s' to ", inet_ntoa(ip->ip_src)); 420 printf("`%s', len %d\n", inet_ntoa(ip->ip_dst), icmplen); 421 } 422 #endif 423 if (icmplen < ICMP_MINLEN) { 424 ICMP_STATINC(ICMP_STAT_TOOSHORT); 425 goto freeit; 426 } 427 i = hlen + min(icmplen, ICMP_ADVLENMIN); 428 if ((m->m_len < i || M_READONLY(m)) && (m = m_pullup(m, i)) == 0) { 429 ICMP_STATINC(ICMP_STAT_TOOSHORT); 430 return; 431 } 432 ip = mtod(m, struct ip *); 433 m->m_len -= hlen; 434 m->m_data += hlen; 435 icp = mtod(m, struct icmp *); 436 /* Don't need to assert alignment, here. */ 437 if (in_cksum(m, icmplen)) { 438 ICMP_STATINC(ICMP_STAT_CHECKSUM); 439 goto freeit; 440 } 441 m->m_len += hlen; 442 m->m_data -= hlen; 443 444 #ifdef ICMPPRINTFS 445 /* 446 * Message type specific processing. 447 */ 448 if (icmpprintfs) 449 printf("icmp_input(type:%d, code:%d)\n", icp->icmp_type, 450 icp->icmp_code); 451 #endif 452 if (icp->icmp_type > ICMP_MAXTYPE) 453 goto raw; 454 ICMP_STATINC(ICMP_STAT_INHIST + icp->icmp_type); 455 code = icp->icmp_code; 456 switch (icp->icmp_type) { 457 458 case ICMP_UNREACH: 459 switch (code) { 460 case ICMP_UNREACH_NET: 461 code = PRC_UNREACH_NET; 462 break; 463 464 case ICMP_UNREACH_HOST: 465 code = PRC_UNREACH_HOST; 466 break; 467 468 case ICMP_UNREACH_PROTOCOL: 469 code = PRC_UNREACH_PROTOCOL; 470 break; 471 472 case ICMP_UNREACH_PORT: 473 code = PRC_UNREACH_PORT; 474 break; 475 476 case ICMP_UNREACH_SRCFAIL: 477 code = PRC_UNREACH_SRCFAIL; 478 break; 479 480 case ICMP_UNREACH_NEEDFRAG: 481 code = PRC_MSGSIZE; 482 break; 483 484 case ICMP_UNREACH_NET_UNKNOWN: 485 case ICMP_UNREACH_NET_PROHIB: 486 case ICMP_UNREACH_TOSNET: 487 code = PRC_UNREACH_NET; 488 break; 489 490 case ICMP_UNREACH_HOST_UNKNOWN: 491 case ICMP_UNREACH_ISOLATED: 492 case ICMP_UNREACH_HOST_PROHIB: 493 case ICMP_UNREACH_TOSHOST: 494 code = PRC_UNREACH_HOST; 495 break; 496 497 default: 498 goto badcode; 499 } 500 goto deliver; 501 502 case ICMP_TIMXCEED: 503 if (code > 1) 504 goto badcode; 505 code += PRC_TIMXCEED_INTRANS; 506 goto deliver; 507 508 case ICMP_PARAMPROB: 509 if (code > 1) 510 goto badcode; 511 code = PRC_PARAMPROB; 512 goto deliver; 513 514 case ICMP_SOURCEQUENCH: 515 if (code) 516 goto badcode; 517 code = PRC_QUENCH; 518 goto deliver; 519 520 deliver: 521 /* 522 * Problem with datagram; advise higher level routines. 523 */ 524 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 525 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 526 ICMP_STATINC(ICMP_STAT_BADLEN); 527 goto freeit; 528 } 529 if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr)) 530 goto badcode; 531 #ifdef ICMPPRINTFS 532 if (icmpprintfs) 533 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 534 #endif 535 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 536 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 537 if (ctlfunc) 538 (void) (*ctlfunc)(code, sintosa(&icmpsrc), 539 &icp->icmp_ip); 540 break; 541 542 badcode: 543 ICMP_STATINC(ICMP_STAT_BADCODE); 544 break; 545 546 case ICMP_ECHO: 547 if (!icmpbmcastecho && 548 (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 549 ICMP_STATINC(ICMP_STAT_BMCASTECHO); 550 break; 551 } 552 icp->icmp_type = ICMP_ECHOREPLY; 553 goto reflect; 554 555 case ICMP_TSTAMP: 556 if (icmplen < ICMP_TSLEN) { 557 ICMP_STATINC(ICMP_STAT_BADLEN); 558 break; 559 } 560 if (!icmpbmcastecho && 561 (m->m_flags & (M_MCAST | M_BCAST)) != 0) { 562 ICMP_STATINC(ICMP_STAT_BMCASTTSTAMP); 563 break; 564 } 565 icp->icmp_type = ICMP_TSTAMPREPLY; 566 icp->icmp_rtime = iptime(); 567 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 568 goto reflect; 569 570 case ICMP_MASKREQ: 571 if (icmpmaskrepl == 0) 572 break; 573 /* 574 * We are not able to respond with all ones broadcast 575 * unless we receive it over a point-to-point interface. 576 */ 577 if (icmplen < ICMP_MASKLEN) { 578 ICMP_STATINC(ICMP_STAT_BADLEN); 579 break; 580 } 581 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 582 in_nullhost(ip->ip_dst)) 583 icmpdst.sin_addr = ip->ip_src; 584 else 585 icmpdst.sin_addr = ip->ip_dst; 586 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 587 m->m_pkthdr.rcvif)); 588 if (ia == 0) 589 break; 590 icp->icmp_type = ICMP_MASKREPLY; 591 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 592 if (in_nullhost(ip->ip_src)) { 593 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 594 ip->ip_src = ia->ia_broadaddr.sin_addr; 595 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 596 ip->ip_src = ia->ia_dstaddr.sin_addr; 597 } 598 reflect: 599 { 600 uint64_t *icps = percpu_getref(icmpstat_percpu); 601 icps[ICMP_STAT_REFLECT]++; 602 icps[ICMP_STAT_OUTHIST + icp->icmp_type]++; 603 percpu_putref(icmpstat_percpu); 604 } 605 icmp_reflect(m); 606 return; 607 608 case ICMP_REDIRECT: 609 if (code > 3) 610 goto badcode; 611 if (icmp_rediraccept == 0) 612 goto freeit; 613 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 614 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 615 ICMP_STATINC(ICMP_STAT_BADLEN); 616 break; 617 } 618 /* 619 * Short circuit routing redirects to force 620 * immediate change in the kernel's routing 621 * tables. The message is also handed to anyone 622 * listening on a raw socket (e.g. the routing 623 * daemon for use in updating its tables). 624 */ 625 icmpgw.sin_addr = ip->ip_src; 626 icmpdst.sin_addr = icp->icmp_gwaddr; 627 #ifdef ICMPPRINTFS 628 if (icmpprintfs) { 629 printf("redirect dst `%s' to `%s'\n", 630 inet_ntoa(icp->icmp_ip.ip_dst), 631 inet_ntoa(icp->icmp_gwaddr)); 632 } 633 #endif 634 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 635 rt = NULL; 636 rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst), 637 NULL, RTF_GATEWAY | RTF_HOST, sintosa(&icmpgw), &rt); 638 if (rt != NULL && icmp_redirtimeout != 0) { 639 i = rt_timer_add(rt, icmp_redirect_timeout, 640 icmp_redirect_timeout_q); 641 if (i) 642 log(LOG_ERR, "ICMP: redirect failed to " 643 "register timeout for route to %x, " 644 "code %d\n", 645 icp->icmp_ip.ip_dst.s_addr, i); 646 } 647 if (rt != NULL) 648 rtfree(rt); 649 650 pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc)); 651 #if defined(IPSEC) || defined(FAST_IPSEC) 652 key_sa_routechange((struct sockaddr *)&icmpsrc); 653 #endif 654 break; 655 656 /* 657 * No kernel processing for the following; 658 * just fall through to send to raw listener. 659 */ 660 case ICMP_ECHOREPLY: 661 case ICMP_ROUTERADVERT: 662 case ICMP_ROUTERSOLICIT: 663 case ICMP_TSTAMPREPLY: 664 case ICMP_IREQREPLY: 665 case ICMP_MASKREPLY: 666 default: 667 break; 668 } 669 670 raw: 671 rip_input(m, hlen, proto); 672 return; 673 674 freeit: 675 m_freem(m); 676 return; 677 } 678 679 /* 680 * Reflect the ip packet back to the source 681 */ 682 void 683 icmp_reflect(struct mbuf *m) 684 { 685 struct ip *ip = mtod(m, struct ip *); 686 struct in_ifaddr *ia; 687 struct ifaddr *ifa; 688 struct sockaddr_in *sin = 0; 689 struct in_addr t; 690 struct mbuf *opts = 0; 691 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 692 693 if (!in_canforward(ip->ip_src) && 694 ((ip->ip_src.s_addr & IN_CLASSA_NET) != 695 htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 696 m_freem(m); /* Bad return address */ 697 goto done; /* ip_output() will check for broadcast */ 698 } 699 t = ip->ip_dst; 700 ip->ip_dst = ip->ip_src; 701 /* 702 * If the incoming packet was addressed directly to us, use 703 * dst as the src for the reply. Otherwise (broadcast or 704 * anonymous), use an address which corresponds to the 705 * incoming interface, with a preference for the address which 706 * corresponds to the route to the destination of the ICMP. 707 */ 708 709 /* Look for packet addressed to us */ 710 INADDR_TO_IA(t, ia); 711 712 /* look for packet sent to broadcast address */ 713 if (ia == NULL && m->m_pkthdr.rcvif && 714 (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 715 IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) { 716 if (ifa->ifa_addr->sa_family != AF_INET) 717 continue; 718 if (in_hosteq(t,ifatoia(ifa)->ia_broadaddr.sin_addr)) { 719 ia = ifatoia(ifa); 720 break; 721 } 722 } 723 } 724 725 if (ia) 726 sin = &ia->ia_addr; 727 728 icmpdst.sin_addr = t; 729 730 /* 731 * if the packet is addressed somewhere else, compute the 732 * source address for packets routed back to the source, and 733 * use that, if it's an address on the interface which 734 * received the packet 735 */ 736 if (sin == NULL && m->m_pkthdr.rcvif) { 737 struct sockaddr_in sin_dst; 738 struct route icmproute; 739 int errornum; 740 741 sockaddr_in_init(&sin_dst, &ip->ip_dst, 0); 742 memset(&icmproute, 0, sizeof(icmproute)); 743 errornum = 0; 744 sin = in_selectsrc(&sin_dst, &icmproute, 0, NULL, &errornum); 745 /* errornum is never used */ 746 rtcache_free(&icmproute); 747 /* check to make sure sin is a source address on rcvif */ 748 if (sin) { 749 t = sin->sin_addr; 750 sin = NULL; 751 INADDR_TO_IA(t, ia); 752 while (ia) { 753 if (ia->ia_ifp == m->m_pkthdr.rcvif) { 754 sin = &ia->ia_addr; 755 break; 756 } 757 NEXT_IA_WITH_SAME_ADDR(ia); 758 } 759 } 760 } 761 762 /* 763 * if it was not addressed to us, but the route doesn't go out 764 * the source interface, pick an address on the source 765 * interface. This can happen when routing is asymmetric, or 766 * when the incoming packet was encapsulated 767 */ 768 if (sin == NULL && m->m_pkthdr.rcvif) { 769 IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) { 770 if (ifa->ifa_addr->sa_family != AF_INET) 771 continue; 772 sin = &(ifatoia(ifa)->ia_addr); 773 break; 774 } 775 } 776 777 /* 778 * The following happens if the packet was not addressed to us, 779 * and was received on an interface with no IP address: 780 * We find the first AF_INET address on the first non-loopback 781 * interface. 782 */ 783 if (sin == NULL) 784 TAILQ_FOREACH(ia, &in_ifaddrhead, ia_list) { 785 if (ia->ia_ifp->if_flags & IFF_LOOPBACK) 786 continue; 787 sin = &ia->ia_addr; 788 break; 789 } 790 791 /* 792 * If we still didn't find an address, punt. We could have an 793 * interface up (and receiving packets) with no address. 794 */ 795 if (sin == NULL) { 796 m_freem(m); 797 goto done; 798 } 799 800 ip->ip_src = sin->sin_addr; 801 ip->ip_ttl = MAXTTL; 802 803 if (optlen > 0) { 804 u_char *cp; 805 int opt, cnt; 806 u_int len; 807 808 /* 809 * Retrieve any source routing from the incoming packet; 810 * add on any record-route or timestamp options. 811 */ 812 cp = (u_char *) (ip + 1); 813 if ((opts = ip_srcroute()) == 0 && 814 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 815 MCLAIM(opts, m->m_owner); 816 opts->m_len = sizeof(struct in_addr); 817 *mtod(opts, struct in_addr *) = zeroin_addr; 818 } 819 if (opts) { 820 #ifdef ICMPPRINTFS 821 if (icmpprintfs) 822 printf("icmp_reflect optlen %d rt %d => ", 823 optlen, opts->m_len); 824 #endif 825 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 826 opt = cp[IPOPT_OPTVAL]; 827 if (opt == IPOPT_EOL) 828 break; 829 if (opt == IPOPT_NOP) 830 len = 1; 831 else { 832 if (cnt < IPOPT_OLEN + sizeof(*cp)) 833 break; 834 len = cp[IPOPT_OLEN]; 835 if (len < IPOPT_OLEN + sizeof(*cp) || 836 len > cnt) 837 break; 838 } 839 /* 840 * Should check for overflow, but it "can't happen" 841 */ 842 if (opt == IPOPT_RR || opt == IPOPT_TS || 843 opt == IPOPT_SECURITY) { 844 memmove(mtod(opts, char *) + opts->m_len, 845 cp, len); 846 opts->m_len += len; 847 } 848 } 849 /* Terminate & pad, if necessary */ 850 if ((cnt = opts->m_len % 4) != 0) { 851 for (; cnt < 4; cnt++) { 852 *(mtod(opts, char *) + opts->m_len) = 853 IPOPT_EOL; 854 opts->m_len++; 855 } 856 } 857 #ifdef ICMPPRINTFS 858 if (icmpprintfs) 859 printf("%d\n", opts->m_len); 860 #endif 861 } 862 /* 863 * Now strip out original options by copying rest of first 864 * mbuf's data back, and adjust the IP length. 865 */ 866 ip->ip_len = htons(ntohs(ip->ip_len) - optlen); 867 ip->ip_hl = sizeof(struct ip) >> 2; 868 m->m_len -= optlen; 869 if (m->m_flags & M_PKTHDR) 870 m->m_pkthdr.len -= optlen; 871 optlen += sizeof(struct ip); 872 memmove(ip + 1, (char *)ip + optlen, 873 (unsigned)(m->m_len - sizeof(struct ip))); 874 } 875 m_tag_delete_nonpersistent(m); 876 m->m_flags &= ~(M_BCAST|M_MCAST); 877 878 /* 879 * Clear any in-bound checksum flags for this packet. 880 */ 881 if (m->m_flags & M_PKTHDR) 882 m->m_pkthdr.csum_flags = 0; 883 884 icmp_send(m, opts); 885 done: 886 if (opts) 887 (void)m_free(opts); 888 } 889 890 /* 891 * Send an icmp packet back to the ip level, 892 * after supplying a checksum. 893 */ 894 void 895 icmp_send(struct mbuf *m, struct mbuf *opts) 896 { 897 struct ip *ip = mtod(m, struct ip *); 898 int hlen; 899 struct icmp *icp; 900 901 hlen = ip->ip_hl << 2; 902 m->m_data += hlen; 903 m->m_len -= hlen; 904 icp = mtod(m, struct icmp *); 905 icp->icmp_cksum = 0; 906 icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen); 907 m->m_data -= hlen; 908 m->m_len += hlen; 909 #ifdef ICMPPRINTFS 910 if (icmpprintfs) { 911 printf("icmp_send to destination `%s' from `%s'\n", 912 inet_ntoa(ip->ip_dst), inet_ntoa(ip->ip_src)); 913 } 914 #endif 915 (void)ip_output(m, opts, NULL, 0, NULL, NULL); 916 } 917 918 n_time 919 iptime(void) 920 { 921 struct timeval atv; 922 u_long t; 923 924 microtime(&atv); 925 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 926 return (htonl(t)); 927 } 928 929 /* 930 * sysctl helper routine for net.inet.icmp.returndatabytes. ensures 931 * that the new value is in the correct range. 932 */ 933 static int 934 sysctl_net_inet_icmp_returndatabytes(SYSCTLFN_ARGS) 935 { 936 int error, t; 937 struct sysctlnode node; 938 939 node = *rnode; 940 node.sysctl_data = &t; 941 t = icmpreturndatabytes; 942 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 943 if (error || newp == NULL) 944 return (error); 945 946 if (t < 8 || t > 512) 947 return (EINVAL); 948 icmpreturndatabytes = t; 949 950 return (0); 951 } 952 953 /* 954 * sysctl helper routine for net.inet.icmp.redirtimeout. ensures that 955 * the given value is not less than zero and then resets the timeout 956 * queue. 957 */ 958 static int 959 sysctl_net_inet_icmp_redirtimeout(SYSCTLFN_ARGS) 960 { 961 int error, tmp; 962 struct sysctlnode node; 963 964 node = *rnode; 965 node.sysctl_data = &tmp; 966 tmp = icmp_redirtimeout; 967 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 968 if (error || newp == NULL) 969 return (error); 970 if (tmp < 0) 971 return (EINVAL); 972 icmp_redirtimeout = tmp; 973 974 /* 975 * was it a *defined* side-effect that anyone even *reading* 976 * this value causes these things to happen? 977 */ 978 if (icmp_redirect_timeout_q != NULL) { 979 if (icmp_redirtimeout == 0) { 980 rt_timer_queue_destroy(icmp_redirect_timeout_q, 981 true); 982 icmp_redirect_timeout_q = NULL; 983 } else { 984 rt_timer_queue_change(icmp_redirect_timeout_q, 985 icmp_redirtimeout); 986 } 987 } else if (icmp_redirtimeout > 0) { 988 icmp_redirect_timeout_q = 989 rt_timer_queue_create(icmp_redirtimeout); 990 } 991 992 return (0); 993 } 994 995 static int 996 sysctl_net_inet_icmp_stats(SYSCTLFN_ARGS) 997 { 998 999 return (NETSTAT_SYSCTL(icmpstat_percpu, ICMP_NSTATS)); 1000 } 1001 1002 static void 1003 sysctl_netinet_icmp_setup(struct sysctllog **clog) 1004 { 1005 1006 sysctl_createv(clog, 0, NULL, NULL, 1007 CTLFLAG_PERMANENT, 1008 CTLTYPE_NODE, "net", NULL, 1009 NULL, 0, NULL, 0, 1010 CTL_NET, CTL_EOL); 1011 sysctl_createv(clog, 0, NULL, NULL, 1012 CTLFLAG_PERMANENT, 1013 CTLTYPE_NODE, "inet", NULL, 1014 NULL, 0, NULL, 0, 1015 CTL_NET, PF_INET, CTL_EOL); 1016 sysctl_createv(clog, 0, NULL, NULL, 1017 CTLFLAG_PERMANENT, 1018 CTLTYPE_NODE, "icmp", 1019 SYSCTL_DESCR("ICMPv4 related settings"), 1020 NULL, 0, NULL, 0, 1021 CTL_NET, PF_INET, IPPROTO_ICMP, CTL_EOL); 1022 1023 sysctl_createv(clog, 0, NULL, NULL, 1024 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1025 CTLTYPE_INT, "maskrepl", 1026 SYSCTL_DESCR("Respond to ICMP_MASKREQ messages"), 1027 NULL, 0, &icmpmaskrepl, 0, 1028 CTL_NET, PF_INET, IPPROTO_ICMP, 1029 ICMPCTL_MASKREPL, CTL_EOL); 1030 sysctl_createv(clog, 0, NULL, NULL, 1031 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1032 CTLTYPE_INT, "returndatabytes", 1033 SYSCTL_DESCR("Number of bytes to return in an ICMP " 1034 "error message"), 1035 sysctl_net_inet_icmp_returndatabytes, 0, 1036 &icmpreturndatabytes, 0, 1037 CTL_NET, PF_INET, IPPROTO_ICMP, 1038 ICMPCTL_RETURNDATABYTES, CTL_EOL); 1039 sysctl_createv(clog, 0, NULL, NULL, 1040 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1041 CTLTYPE_INT, "errppslimit", 1042 SYSCTL_DESCR("Maximum number of outgoing ICMP error " 1043 "messages per second"), 1044 NULL, 0, &icmperrppslim, 0, 1045 CTL_NET, PF_INET, IPPROTO_ICMP, 1046 ICMPCTL_ERRPPSLIMIT, CTL_EOL); 1047 sysctl_createv(clog, 0, NULL, NULL, 1048 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1049 CTLTYPE_INT, "rediraccept", 1050 SYSCTL_DESCR("Accept ICMP_REDIRECT messages"), 1051 NULL, 0, &icmp_rediraccept, 0, 1052 CTL_NET, PF_INET, IPPROTO_ICMP, 1053 ICMPCTL_REDIRACCEPT, CTL_EOL); 1054 sysctl_createv(clog, 0, NULL, NULL, 1055 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1056 CTLTYPE_INT, "redirtimeout", 1057 SYSCTL_DESCR("Lifetime of ICMP_REDIRECT generated " 1058 "routes"), 1059 sysctl_net_inet_icmp_redirtimeout, 0, 1060 &icmp_redirtimeout, 0, 1061 CTL_NET, PF_INET, IPPROTO_ICMP, 1062 ICMPCTL_REDIRTIMEOUT, CTL_EOL); 1063 sysctl_createv(clog, 0, NULL, NULL, 1064 CTLFLAG_PERMANENT, 1065 CTLTYPE_STRUCT, "stats", 1066 SYSCTL_DESCR("ICMP statistics"), 1067 sysctl_net_inet_icmp_stats, 0, NULL, 0, 1068 CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_STATS, 1069 CTL_EOL); 1070 sysctl_createv(clog, 0, NULL, NULL, 1071 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1072 CTLTYPE_INT, "bmcastecho", 1073 SYSCTL_DESCR("Respond to ICMP_ECHO or ICMP_TIMESTAMP " 1074 "message to the broadcast or multicast"), 1075 NULL, 0, &icmpbmcastecho, 0, 1076 CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_BMCASTECHO, 1077 CTL_EOL); 1078 } 1079 1080 void 1081 icmp_statinc(u_int stat) 1082 { 1083 1084 KASSERT(stat < ICMP_NSTATS); 1085 ICMP_STATINC(stat); 1086 } 1087 1088 /* Table of common MTUs: */ 1089 1090 static const u_int mtu_table[] = { 1091 65535, 65280, 32000, 17914, 9180, 8166, 1092 4352, 2002, 1492, 1006, 508, 296, 68, 0 1093 }; 1094 1095 void 1096 icmp_mtudisc(struct icmp *icp, struct in_addr faddr) 1097 { 1098 struct icmp_mtudisc_callback *mc; 1099 struct sockaddr *dst = sintosa(&icmpsrc); 1100 struct rtentry *rt; 1101 u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */ 1102 int error; 1103 1104 rt = rtalloc1(dst, 1); 1105 if (rt == 0) 1106 return; 1107 1108 /* If we didn't get a host route, allocate one */ 1109 1110 if ((rt->rt_flags & RTF_HOST) == 0) { 1111 struct rtentry *nrt; 1112 1113 error = rtrequest((int) RTM_ADD, dst, 1114 (struct sockaddr *) rt->rt_gateway, 1115 (struct sockaddr *) 0, 1116 RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt); 1117 if (error) { 1118 rtfree(rt); 1119 return; 1120 } 1121 nrt->rt_rmx = rt->rt_rmx; 1122 rtfree(rt); 1123 rt = nrt; 1124 } 1125 error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q); 1126 if (error) { 1127 rtfree(rt); 1128 return; 1129 } 1130 1131 if (mtu == 0) { 1132 int i = 0; 1133 1134 mtu = ntohs(icp->icmp_ip.ip_len); 1135 /* Some 4.2BSD-based routers incorrectly adjust the ip_len */ 1136 if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0) 1137 mtu -= (icp->icmp_ip.ip_hl << 2); 1138 1139 /* If we still can't guess a value, try the route */ 1140 1141 if (mtu == 0) { 1142 mtu = rt->rt_rmx.rmx_mtu; 1143 1144 /* If no route mtu, default to the interface mtu */ 1145 1146 if (mtu == 0) 1147 mtu = rt->rt_ifp->if_mtu; 1148 } 1149 1150 for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++) 1151 if (mtu > mtu_table[i]) { 1152 mtu = mtu_table[i]; 1153 break; 1154 } 1155 } 1156 1157 /* 1158 * XXX: RTV_MTU is overloaded, since the admin can set it 1159 * to turn off PMTU for a route, and the kernel can 1160 * set it to indicate a serious problem with PMTU 1161 * on a route. We should be using a separate flag 1162 * for the kernel to indicate this. 1163 */ 1164 1165 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 1166 if (mtu < 296 || mtu > rt->rt_ifp->if_mtu) 1167 rt->rt_rmx.rmx_locks |= RTV_MTU; 1168 else if (rt->rt_rmx.rmx_mtu > mtu || 1169 rt->rt_rmx.rmx_mtu == 0) { 1170 ICMP_STATINC(ICMP_STAT_PMTUCHG); 1171 rt->rt_rmx.rmx_mtu = mtu; 1172 } 1173 } 1174 1175 if (rt) 1176 rtfree(rt); 1177 1178 /* 1179 * Notify protocols that the MTU for this destination 1180 * has changed. 1181 */ 1182 for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL; 1183 mc = LIST_NEXT(mc, mc_list)) 1184 (*mc->mc_func)(faddr); 1185 } 1186 1187 /* 1188 * Return the next larger or smaller MTU plateau (table from RFC 1191) 1189 * given current value MTU. If DIR is less than zero, a larger plateau 1190 * is returned; otherwise, a smaller value is returned. 1191 */ 1192 u_int 1193 ip_next_mtu(u_int mtu, int dir) /* XXX */ 1194 { 1195 int i; 1196 1197 for (i = 0; i < (sizeof mtu_table) / (sizeof mtu_table[0]); i++) { 1198 if (mtu >= mtu_table[i]) 1199 break; 1200 } 1201 1202 if (dir < 0) { 1203 if (i == 0) { 1204 return 0; 1205 } else { 1206 return mtu_table[i - 1]; 1207 } 1208 } else { 1209 if (mtu_table[i] == 0) { 1210 return 0; 1211 } else if (mtu > mtu_table[i]) { 1212 return mtu_table[i]; 1213 } else { 1214 return mtu_table[i + 1]; 1215 } 1216 } 1217 } 1218 1219 static void 1220 icmp_mtudisc_timeout(struct rtentry *rt, struct rttimer *r) 1221 { 1222 if (rt == NULL) 1223 panic("icmp_mtudisc_timeout: bad route to timeout"); 1224 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 1225 (RTF_DYNAMIC | RTF_HOST)) { 1226 rtrequest((int) RTM_DELETE, rt_getkey(rt), 1227 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 1228 } else { 1229 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 1230 rt->rt_rmx.rmx_mtu = 0; 1231 } 1232 } 1233 } 1234 1235 static void 1236 icmp_redirect_timeout(struct rtentry *rt, struct rttimer *r) 1237 { 1238 if (rt == NULL) 1239 panic("icmp_redirect_timeout: bad route to timeout"); 1240 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 1241 (RTF_DYNAMIC | RTF_HOST)) { 1242 rtrequest((int) RTM_DELETE, rt_getkey(rt), 1243 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 1244 } 1245 } 1246 1247 /* 1248 * Perform rate limit check. 1249 * Returns 0 if it is okay to send the icmp packet. 1250 * Returns 1 if the router SHOULD NOT send this icmp packet due to rate 1251 * limitation. 1252 * 1253 * XXX per-destination/type check necessary? 1254 */ 1255 int 1256 icmp_ratelimit(const struct in_addr *dst, const int type, 1257 const int code) 1258 { 1259 1260 /* PPS limit */ 1261 if (!ppsratecheck(&icmperrppslim_last, &icmperrpps_count, 1262 icmperrppslim)) { 1263 /* The packet is subject to rate limit */ 1264 return 1; 1265 } 1266 1267 /* okay to send */ 1268 return 0; 1269 } 1270