ip_icmp.c revision 1.34
1 /* $NetBSD: ip_icmp.c,v 1.34 1999/01/19 23:03:21 mycroft Exp $ */ 2 3 /*- 4 * Copyright (c) 1998 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Public Access Networks Corporation ("Panix"). It was developed under 9 * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Copyright (c) 1982, 1986, 1988, 1993 42 * The Regents of the University of California. All rights reserved. 43 * 44 * Redistribution and use in source and binary forms, with or without 45 * modification, are permitted provided that the following conditions 46 * are met: 47 * 1. Redistributions of source code must retain the above copyright 48 * notice, this list of conditions and the following disclaimer. 49 * 2. Redistributions in binary form must reproduce the above copyright 50 * notice, this list of conditions and the following disclaimer in the 51 * documentation and/or other materials provided with the distribution. 52 * 3. All advertising materials mentioning features or use of this software 53 * must display the following acknowledgement: 54 * This product includes software developed by the University of 55 * California, Berkeley and its contributors. 56 * 4. Neither the name of the University nor the names of its contributors 57 * may be used to endorse or promote products derived from this software 58 * without specific prior written permission. 59 * 60 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 61 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 62 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 63 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 64 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 65 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 66 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 70 * SUCH DAMAGE. 71 * 72 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 73 */ 74 75 #include <sys/param.h> 76 #include <sys/systm.h> 77 #include <sys/malloc.h> 78 #include <sys/mbuf.h> 79 #include <sys/protosw.h> 80 #include <sys/socket.h> 81 #include <sys/time.h> 82 #include <sys/kernel.h> 83 #include <sys/proc.h> 84 85 #include <vm/vm.h> 86 #include <sys/sysctl.h> 87 88 #include <net/if.h> 89 #include <net/route.h> 90 91 #include <netinet/in.h> 92 #include <netinet/in_systm.h> 93 #include <netinet/in_var.h> 94 #include <netinet/ip.h> 95 #include <netinet/ip_icmp.h> 96 #include <netinet/ip_var.h> 97 #include <netinet/icmp_var.h> 98 99 #include <machine/stdarg.h> 100 101 /* 102 * ICMP routines: error generation, receive packet processing, and 103 * routines to turnaround packets back to the originator, and 104 * host table maintenance routines. 105 */ 106 107 int icmpmaskrepl = 0; 108 #ifdef ICMPPRINTFS 109 int icmpprintfs = 0; 110 #endif 111 112 extern struct protosw inetsw[]; 113 114 static void icmp_mtudisc __P((struct icmp *)); 115 static void icmp_mtudisc_timeout __P((struct rtentry *, struct rttimer *)); 116 117 /* 118 * Generate an error packet of type error 119 * in response to bad packet ip. 120 */ 121 void 122 icmp_error(n, type, code, dest, destifp) 123 struct mbuf *n; 124 int type, code; 125 n_long dest; 126 struct ifnet *destifp; 127 { 128 register struct ip *oip = mtod(n, struct ip *), *nip; 129 register unsigned oiplen = oip->ip_hl << 2; 130 register struct icmp *icp; 131 register struct mbuf *m; 132 unsigned icmplen; 133 134 #ifdef ICMPPRINTFS 135 if (icmpprintfs) 136 printf("icmp_error(%x, %d, %d)\n", oip, type, code); 137 #endif 138 if (type != ICMP_REDIRECT) 139 icmpstat.icps_error++; 140 /* 141 * Don't send error if not the first fragment of message. 142 * Don't error if the old packet protocol was ICMP 143 * error message, only known informational types. 144 */ 145 if (oip->ip_off &~ (IP_MF|IP_DF)) 146 goto freeit; 147 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 148 n->m_len >= oiplen + ICMP_MINLEN && 149 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { 150 icmpstat.icps_oldicmp++; 151 goto freeit; 152 } 153 /* Don't send error in response to a multicast or broadcast packet */ 154 if (n->m_flags & (M_BCAST|M_MCAST)) 155 goto freeit; 156 /* 157 * First, formulate icmp message 158 */ 159 m = m_gethdr(M_DONTWAIT, MT_HEADER); 160 if (m == NULL) 161 goto freeit; 162 icmplen = oiplen + min(8, oip->ip_len - oiplen); 163 m->m_len = icmplen + ICMP_MINLEN; 164 MH_ALIGN(m, m->m_len); 165 icp = mtod(m, struct icmp *); 166 if ((u_int)type > ICMP_MAXTYPE) 167 panic("icmp_error"); 168 icmpstat.icps_outhist[type]++; 169 icp->icmp_type = type; 170 if (type == ICMP_REDIRECT) 171 icp->icmp_gwaddr.s_addr = dest; 172 else { 173 icp->icmp_void = 0; 174 /* 175 * The following assignments assume an overlay with the 176 * zeroed icmp_void field. 177 */ 178 if (type == ICMP_PARAMPROB) { 179 icp->icmp_pptr = code; 180 code = 0; 181 } else if (type == ICMP_UNREACH && 182 code == ICMP_UNREACH_NEEDFRAG && destifp) 183 icp->icmp_nextmtu = htons(destifp->if_mtu); 184 } 185 186 HTONS(oip->ip_id); 187 HTONS(oip->ip_off); 188 HTONS(oip->ip_len); 189 icp->icmp_code = code; 190 bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen); 191 nip = &icp->icmp_ip; 192 193 /* 194 * Now, copy old ip header (without options) 195 * in front of icmp message. 196 */ 197 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 198 panic("icmp len"); 199 m->m_data -= sizeof(struct ip); 200 m->m_len += sizeof(struct ip); 201 m->m_pkthdr.len = m->m_len; 202 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 203 nip = mtod(m, struct ip *); 204 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); 205 nip->ip_len = m->m_len; 206 nip->ip_hl = sizeof(struct ip) >> 2; 207 nip->ip_p = IPPROTO_ICMP; 208 nip->ip_tos = 0; 209 icmp_reflect(m); 210 211 freeit: 212 m_freem(n); 213 } 214 215 static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; 216 static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; 217 static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; 218 struct sockaddr_in icmpmask = { 8, 0 }; 219 220 /* 221 * Process a received ICMP message. 222 */ 223 void 224 #if __STDC__ 225 icmp_input(struct mbuf *m, ...) 226 #else 227 icmp_input(m, va_alist) 228 struct mbuf *m; 229 va_dcl 230 #endif 231 { 232 register struct icmp *icp; 233 register struct ip *ip = mtod(m, struct ip *); 234 int icmplen; 235 register int i; 236 struct in_ifaddr *ia; 237 void *(*ctlfunc) __P((int, struct sockaddr *, void *)); 238 int code; 239 extern u_char ip_protox[]; 240 int hlen; 241 va_list ap; 242 243 va_start(ap, m); 244 hlen = va_arg(ap, int); 245 va_end(ap); 246 247 /* 248 * Locate icmp structure in mbuf, and check 249 * that not corrupted and of at least minimum length. 250 */ 251 icmplen = ip->ip_len - hlen; 252 #ifdef ICMPPRINTFS 253 if (icmpprintfs) 254 printf("icmp_input from %x to %x, len %d\n", 255 ntohl(ip->ip_src.s_addr), ntohl(ip->ip_dst.s_addr), 256 icmplen); 257 #endif 258 if (icmplen < ICMP_MINLEN) { 259 icmpstat.icps_tooshort++; 260 goto freeit; 261 } 262 i = hlen + min(icmplen, ICMP_ADVLENMIN); 263 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 264 icmpstat.icps_tooshort++; 265 return; 266 } 267 ip = mtod(m, struct ip *); 268 m->m_len -= hlen; 269 m->m_data += hlen; 270 icp = mtod(m, struct icmp *); 271 if (in_cksum(m, icmplen)) { 272 icmpstat.icps_checksum++; 273 goto freeit; 274 } 275 m->m_len += hlen; 276 m->m_data -= hlen; 277 278 #ifdef ICMPPRINTFS 279 /* 280 * Message type specific processing. 281 */ 282 if (icmpprintfs) 283 printf("icmp_input, type %d code %d\n", icp->icmp_type, 284 icp->icmp_code); 285 #endif 286 if (icp->icmp_type > ICMP_MAXTYPE) 287 goto raw; 288 icmpstat.icps_inhist[icp->icmp_type]++; 289 code = icp->icmp_code; 290 switch (icp->icmp_type) { 291 292 case ICMP_UNREACH: 293 switch (code) { 294 case ICMP_UNREACH_NET: 295 case ICMP_UNREACH_HOST: 296 case ICMP_UNREACH_PROTOCOL: 297 case ICMP_UNREACH_PORT: 298 case ICMP_UNREACH_SRCFAIL: 299 code += PRC_UNREACH_NET; 300 break; 301 302 case ICMP_UNREACH_NEEDFRAG: 303 code = PRC_MSGSIZE; 304 break; 305 306 case ICMP_UNREACH_NET_UNKNOWN: 307 case ICMP_UNREACH_NET_PROHIB: 308 case ICMP_UNREACH_TOSNET: 309 code = PRC_UNREACH_NET; 310 break; 311 312 case ICMP_UNREACH_HOST_UNKNOWN: 313 case ICMP_UNREACH_ISOLATED: 314 case ICMP_UNREACH_HOST_PROHIB: 315 case ICMP_UNREACH_TOSHOST: 316 code = PRC_UNREACH_HOST; 317 break; 318 319 default: 320 goto badcode; 321 } 322 goto deliver; 323 324 case ICMP_TIMXCEED: 325 if (code > 1) 326 goto badcode; 327 code += PRC_TIMXCEED_INTRANS; 328 goto deliver; 329 330 case ICMP_PARAMPROB: 331 if (code > 1) 332 goto badcode; 333 code = PRC_PARAMPROB; 334 goto deliver; 335 336 case ICMP_SOURCEQUENCH: 337 if (code) 338 goto badcode; 339 code = PRC_QUENCH; 340 goto deliver; 341 342 deliver: 343 /* 344 * Problem with datagram; advise higher level routines. 345 */ 346 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 347 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 348 icmpstat.icps_badlen++; 349 goto freeit; 350 } 351 if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr)) 352 goto badcode; 353 NTOHS(icp->icmp_ip.ip_len); 354 #ifdef ICMPPRINTFS 355 if (icmpprintfs) 356 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 357 #endif 358 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 359 if (code == PRC_MSGSIZE && ip_mtudisc) 360 icmp_mtudisc(icp); 361 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 362 if (ctlfunc) 363 (*ctlfunc)(code, sintosa(&icmpsrc), &icp->icmp_ip); 364 break; 365 366 badcode: 367 icmpstat.icps_badcode++; 368 break; 369 370 case ICMP_ECHO: 371 icp->icmp_type = ICMP_ECHOREPLY; 372 goto reflect; 373 374 case ICMP_TSTAMP: 375 if (icmplen < ICMP_TSLEN) { 376 icmpstat.icps_badlen++; 377 break; 378 } 379 icp->icmp_type = ICMP_TSTAMPREPLY; 380 icp->icmp_rtime = iptime(); 381 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 382 goto reflect; 383 384 case ICMP_MASKREQ: 385 if (icmpmaskrepl == 0) 386 break; 387 /* 388 * We are not able to respond with all ones broadcast 389 * unless we receive it over a point-to-point interface. 390 */ 391 if (icmplen < ICMP_MASKLEN) { 392 icmpstat.icps_badlen++; 393 break; 394 } 395 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 396 in_nullhost(ip->ip_dst)) 397 icmpdst.sin_addr = ip->ip_src; 398 else 399 icmpdst.sin_addr = ip->ip_dst; 400 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 401 m->m_pkthdr.rcvif)); 402 if (ia == 0) 403 break; 404 icp->icmp_type = ICMP_MASKREPLY; 405 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 406 if (in_nullhost(ip->ip_src)) { 407 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 408 ip->ip_src = ia->ia_broadaddr.sin_addr; 409 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 410 ip->ip_src = ia->ia_dstaddr.sin_addr; 411 } 412 reflect: 413 icmpstat.icps_reflect++; 414 icmpstat.icps_outhist[icp->icmp_type]++; 415 icmp_reflect(m); 416 return; 417 418 case ICMP_REDIRECT: 419 if (code > 3) 420 goto badcode; 421 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 422 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 423 icmpstat.icps_badlen++; 424 break; 425 } 426 /* 427 * Short circuit routing redirects to force 428 * immediate change in the kernel's routing 429 * tables. The message is also handed to anyone 430 * listening on a raw socket (e.g. the routing 431 * daemon for use in updating its tables). 432 */ 433 icmpgw.sin_addr = ip->ip_src; 434 icmpdst.sin_addr = icp->icmp_gwaddr; 435 #ifdef ICMPPRINTFS 436 if (icmpprintfs) 437 printf("redirect dst %x to %x\n", icp->icmp_ip.ip_dst, 438 icp->icmp_gwaddr); 439 #endif 440 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 441 rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst), 442 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 443 sintosa(&icmpgw), (struct rtentry **)0); 444 pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc)); 445 break; 446 447 /* 448 * No kernel processing for the following; 449 * just fall through to send to raw listener. 450 */ 451 case ICMP_ECHOREPLY: 452 case ICMP_ROUTERADVERT: 453 case ICMP_ROUTERSOLICIT: 454 case ICMP_TSTAMPREPLY: 455 case ICMP_IREQREPLY: 456 case ICMP_MASKREPLY: 457 default: 458 break; 459 } 460 461 raw: 462 rip_input(m); 463 return; 464 465 freeit: 466 m_freem(m); 467 } 468 469 /* 470 * Reflect the ip packet back to the source 471 */ 472 void 473 icmp_reflect(m) 474 struct mbuf *m; 475 { 476 register struct ip *ip = mtod(m, struct ip *); 477 register struct in_ifaddr *ia; 478 register struct ifaddr *ifa; 479 struct in_addr t; 480 struct mbuf *opts = 0; 481 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 482 483 if (!in_canforward(ip->ip_src) && 484 ((ip->ip_src.s_addr & IN_CLASSA_NET) != 485 htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 486 m_freem(m); /* Bad return address */ 487 goto done; /* ip_output() will check for broadcast */ 488 } 489 t = ip->ip_dst; 490 ip->ip_dst = ip->ip_src; 491 /* 492 * If the incoming packet was addressed directly to us, 493 * use dst as the src for the reply. Otherwise (broadcast 494 * or anonymous), use the address which corresponds 495 * to the incoming interface. 496 */ 497 INADDR_TO_IA(t, ia); 498 if (ia == NULL && (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 499 for (ifa = m->m_pkthdr.rcvif->if_addrlist.tqh_first; 500 ifa != NULL; ifa = ifa->ifa_list.tqe_next) { 501 if (ifa->ifa_addr->sa_family != AF_INET) 502 continue; 503 ia = ifatoia(ifa); 504 if (in_hosteq(t, ia->ia_broadaddr.sin_addr)) 505 break; 506 } 507 } 508 509 icmpdst.sin_addr = t; 510 if (ia == (struct in_ifaddr *)0) 511 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 512 m->m_pkthdr.rcvif)); 513 /* 514 * The following happens if the packet was not addressed to us, 515 * and was received on an interface with no IP address: 516 * We find the first AF_INET address on the first non-loopback 517 * interface. 518 */ 519 if (ia == (struct in_ifaddr *)0) 520 for (ia = in_ifaddr.tqh_first; ia != NULL; 521 ia = ia->ia_list.tqe_next) { 522 if (ia->ia_ifp->if_flags & IFF_LOOPBACK) 523 continue; 524 break; 525 } 526 t = ia->ia_addr.sin_addr; 527 ip->ip_src = t; 528 ip->ip_ttl = MAXTTL; 529 530 if (optlen > 0) { 531 register u_char *cp; 532 int opt, cnt; 533 u_int len; 534 535 /* 536 * Retrieve any source routing from the incoming packet; 537 * add on any record-route or timestamp options. 538 */ 539 cp = (u_char *) (ip + 1); 540 if ((opts = ip_srcroute()) == 0 && 541 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 542 opts->m_len = sizeof(struct in_addr); 543 *mtod(opts, struct in_addr *) = zeroin_addr; 544 } 545 if (opts) { 546 #ifdef ICMPPRINTFS 547 if (icmpprintfs) 548 printf("icmp_reflect optlen %d rt %d => ", 549 optlen, opts->m_len); 550 #endif 551 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 552 opt = cp[IPOPT_OPTVAL]; 553 if (opt == IPOPT_EOL) 554 break; 555 if (opt == IPOPT_NOP) 556 len = 1; 557 else { 558 len = cp[IPOPT_OLEN]; 559 if (len <= 0 || len > cnt) 560 break; 561 } 562 /* 563 * Should check for overflow, but it "can't happen" 564 */ 565 if (opt == IPOPT_RR || opt == IPOPT_TS || 566 opt == IPOPT_SECURITY) { 567 bcopy((caddr_t)cp, 568 mtod(opts, caddr_t) + opts->m_len, len); 569 opts->m_len += len; 570 } 571 } 572 /* Terminate & pad, if necessary */ 573 if ((cnt = opts->m_len % 4) != 0) { 574 for (; cnt < 4; cnt++) { 575 *(mtod(opts, caddr_t) + opts->m_len) = 576 IPOPT_EOL; 577 opts->m_len++; 578 } 579 } 580 #ifdef ICMPPRINTFS 581 if (icmpprintfs) 582 printf("%d\n", opts->m_len); 583 #endif 584 } 585 /* 586 * Now strip out original options by copying rest of first 587 * mbuf's data back, and adjust the IP length. 588 */ 589 ip->ip_len -= optlen; 590 ip->ip_hl = sizeof(struct ip) >> 2; 591 m->m_len -= optlen; 592 if (m->m_flags & M_PKTHDR) 593 m->m_pkthdr.len -= optlen; 594 optlen += sizeof(struct ip); 595 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 596 (unsigned)(m->m_len - sizeof(struct ip))); 597 } 598 m->m_flags &= ~(M_BCAST|M_MCAST); 599 icmp_send(m, opts); 600 done: 601 if (opts) 602 (void)m_free(opts); 603 } 604 605 /* 606 * Send an icmp packet back to the ip level, 607 * after supplying a checksum. 608 */ 609 void 610 icmp_send(m, opts) 611 register struct mbuf *m; 612 struct mbuf *opts; 613 { 614 register struct ip *ip = mtod(m, struct ip *); 615 register int hlen; 616 register struct icmp *icp; 617 618 hlen = ip->ip_hl << 2; 619 m->m_data += hlen; 620 m->m_len -= hlen; 621 icp = mtod(m, struct icmp *); 622 icp->icmp_cksum = 0; 623 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 624 m->m_data -= hlen; 625 m->m_len += hlen; 626 #ifdef ICMPPRINTFS 627 if (icmpprintfs) 628 printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src); 629 #endif 630 (void) ip_output(m, opts, NULL, 0, NULL); 631 } 632 633 n_time 634 iptime() 635 { 636 struct timeval atv; 637 u_long t; 638 639 microtime(&atv); 640 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 641 return (htonl(t)); 642 } 643 644 int 645 icmp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 646 int *name; 647 u_int namelen; 648 void *oldp; 649 size_t *oldlenp; 650 void *newp; 651 size_t newlen; 652 { 653 654 /* All sysctl names at this level are terminal. */ 655 if (namelen != 1) 656 return (ENOTDIR); 657 658 switch (name[0]) { 659 case ICMPCTL_MASKREPL: 660 return (sysctl_int(oldp, oldlenp, newp, newlen, &icmpmaskrepl)); 661 default: 662 return (ENOPROTOOPT); 663 } 664 /* NOTREACHED */ 665 } 666 667 static void 668 icmp_mtudisc(icp) 669 struct icmp *icp; 670 { 671 struct rtentry *rt; 672 struct sockaddr *dst = sintosa(&icmpsrc); 673 u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */ 674 int error; 675 676 /* Table of common MTUs: */ 677 678 static u_long mtu_table[] = {65535, 65280, 32000, 17914, 9180, 8166, 679 4352, 2002, 1492, 1006, 508, 296, 68, 0}; 680 681 rt = rtalloc1(dst, 1); 682 if (rt == 0) 683 return; 684 685 /* If we didn't get a host route, allocate one */ 686 687 if ((rt->rt_flags & RTF_HOST) == 0) { 688 struct rtentry *nrt; 689 690 error = rtrequest((int) RTM_ADD, dst, 691 (struct sockaddr *) rt->rt_gateway, 692 (struct sockaddr *) 0, 693 RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt); 694 if (error) { 695 rtfree(rt); 696 rtfree(nrt); 697 return; 698 } 699 nrt->rt_rmx = rt->rt_rmx; 700 rtfree(rt); 701 rt = nrt; 702 } 703 error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q); 704 if (error) { 705 rtfree(rt); 706 return; 707 } 708 709 if (mtu == 0) { 710 int i = 0; 711 712 mtu = icp->icmp_ip.ip_len; /* NTOHS happened in deliver: */ 713 /* Some 4.2BSD-based routers incorrectly adjust the ip_len */ 714 if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0) 715 mtu -= (icp->icmp_ip.ip_hl << 2); 716 717 /* If we still can't guess a value, try the route */ 718 719 if (mtu == 0) { 720 mtu = rt->rt_rmx.rmx_mtu; 721 722 /* If no route mtu, default to the interface mtu */ 723 724 if (mtu == 0) 725 mtu = rt->rt_ifp->if_mtu; 726 } 727 728 for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++) 729 if (mtu > mtu_table[i]) { 730 mtu = mtu_table[i]; 731 break; 732 } 733 } 734 735 /* 736 * XXX: RTV_MTU is overloaded, since the admin can set it 737 * to turn off PMTU for a route, and the kernel can 738 * set it to indicate a serious problem with PMTU 739 * on a route. We should be using a separate flag 740 * for the kernel to indicate this. 741 */ 742 743 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 744 if (mtu < 296 || mtu > rt->rt_ifp->if_mtu) 745 rt->rt_rmx.rmx_locks |= RTV_MTU; 746 else if (rt->rt_rmx.rmx_mtu > mtu || 747 rt->rt_rmx.rmx_mtu == 0) 748 rt->rt_rmx.rmx_mtu = mtu; 749 } 750 751 if (rt) 752 rtfree(rt); 753 } 754 755 756 static void 757 icmp_mtudisc_timeout(rt, r) 758 struct rtentry *rt; 759 struct rttimer *r; 760 { 761 if (rt == NULL) 762 panic("icmp_mtudisc_timeout: bad route to timeout"); 763 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 764 (RTF_DYNAMIC | RTF_HOST)) { 765 rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt), 766 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 767 } else { 768 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 769 rt->rt_rmx.rmx_mtu = 0; 770 } 771 } 772 } 773
Indexes created Mon Sep 29 03:10:08 GMT 2025