ip_icmp.c revision 1.36
1 /* $NetBSD: ip_icmp.c,v 1.36 1999/03/30 19:02:56 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_off); 187 HTONS(oip->ip_len); 188 icp->icmp_code = code; 189 bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen); 190 nip = &icp->icmp_ip; 191 192 /* 193 * Now, copy old ip header (without options) 194 * in front of icmp message. 195 */ 196 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 197 panic("icmp len"); 198 m->m_data -= sizeof(struct ip); 199 m->m_len += sizeof(struct ip); 200 m->m_pkthdr.len = m->m_len; 201 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 202 nip = mtod(m, struct ip *); 203 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); 204 nip->ip_len = m->m_len; 205 nip->ip_hl = sizeof(struct ip) >> 2; 206 nip->ip_p = IPPROTO_ICMP; 207 nip->ip_tos = 0; 208 icmp_reflect(m); 209 210 freeit: 211 m_freem(n); 212 } 213 214 static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; 215 static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; 216 static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; 217 struct sockaddr_in icmpmask = { 8, 0 }; 218 219 /* 220 * Process a received ICMP message. 221 */ 222 void 223 #if __STDC__ 224 icmp_input(struct mbuf *m, ...) 225 #else 226 icmp_input(m, va_alist) 227 struct mbuf *m; 228 va_dcl 229 #endif 230 { 231 register struct icmp *icp; 232 register struct ip *ip = mtod(m, struct ip *); 233 int icmplen; 234 register int i; 235 struct in_ifaddr *ia; 236 void *(*ctlfunc) __P((int, struct sockaddr *, void *)); 237 int code; 238 extern u_char ip_protox[]; 239 int hlen; 240 va_list ap; 241 242 va_start(ap, m); 243 hlen = va_arg(ap, int); 244 va_end(ap); 245 246 /* 247 * Locate icmp structure in mbuf, and check 248 * that not corrupted and of at least minimum length. 249 */ 250 icmplen = ip->ip_len - hlen; 251 #ifdef ICMPPRINTFS 252 if (icmpprintfs) 253 printf("icmp_input from %x to %x, len %d\n", 254 ntohl(ip->ip_src.s_addr), ntohl(ip->ip_dst.s_addr), 255 icmplen); 256 #endif 257 if (icmplen < ICMP_MINLEN) { 258 icmpstat.icps_tooshort++; 259 goto freeit; 260 } 261 i = hlen + min(icmplen, ICMP_ADVLENMIN); 262 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 263 icmpstat.icps_tooshort++; 264 return; 265 } 266 ip = mtod(m, struct ip *); 267 m->m_len -= hlen; 268 m->m_data += hlen; 269 icp = mtod(m, struct icmp *); 270 if (in_cksum(m, icmplen)) { 271 icmpstat.icps_checksum++; 272 goto freeit; 273 } 274 m->m_len += hlen; 275 m->m_data -= hlen; 276 277 #ifdef ICMPPRINTFS 278 /* 279 * Message type specific processing. 280 */ 281 if (icmpprintfs) 282 printf("icmp_input, type %d code %d\n", icp->icmp_type, 283 icp->icmp_code); 284 #endif 285 if (icp->icmp_type > ICMP_MAXTYPE) 286 goto raw; 287 icmpstat.icps_inhist[icp->icmp_type]++; 288 code = icp->icmp_code; 289 switch (icp->icmp_type) { 290 291 case ICMP_UNREACH: 292 switch (code) { 293 case ICMP_UNREACH_NET: 294 case ICMP_UNREACH_HOST: 295 case ICMP_UNREACH_PROTOCOL: 296 case ICMP_UNREACH_PORT: 297 case ICMP_UNREACH_SRCFAIL: 298 code += PRC_UNREACH_NET; 299 break; 300 301 case ICMP_UNREACH_NEEDFRAG: 302 code = PRC_MSGSIZE; 303 break; 304 305 case ICMP_UNREACH_NET_UNKNOWN: 306 case ICMP_UNREACH_NET_PROHIB: 307 case ICMP_UNREACH_TOSNET: 308 code = PRC_UNREACH_NET; 309 break; 310 311 case ICMP_UNREACH_HOST_UNKNOWN: 312 case ICMP_UNREACH_ISOLATED: 313 case ICMP_UNREACH_HOST_PROHIB: 314 case ICMP_UNREACH_TOSHOST: 315 code = PRC_UNREACH_HOST; 316 break; 317 318 default: 319 goto badcode; 320 } 321 goto deliver; 322 323 case ICMP_TIMXCEED: 324 if (code > 1) 325 goto badcode; 326 code += PRC_TIMXCEED_INTRANS; 327 goto deliver; 328 329 case ICMP_PARAMPROB: 330 if (code > 1) 331 goto badcode; 332 code = PRC_PARAMPROB; 333 goto deliver; 334 335 case ICMP_SOURCEQUENCH: 336 if (code) 337 goto badcode; 338 code = PRC_QUENCH; 339 goto deliver; 340 341 deliver: 342 /* 343 * Problem with datagram; advise higher level routines. 344 */ 345 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 346 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 347 icmpstat.icps_badlen++; 348 goto freeit; 349 } 350 if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr)) 351 goto badcode; 352 NTOHS(icp->icmp_ip.ip_len); 353 #ifdef ICMPPRINTFS 354 if (icmpprintfs) 355 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 356 #endif 357 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 358 if (code == PRC_MSGSIZE && ip_mtudisc) 359 icmp_mtudisc(icp); 360 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 361 if (ctlfunc) 362 (*ctlfunc)(code, sintosa(&icmpsrc), &icp->icmp_ip); 363 break; 364 365 badcode: 366 icmpstat.icps_badcode++; 367 break; 368 369 case ICMP_ECHO: 370 icp->icmp_type = ICMP_ECHOREPLY; 371 goto reflect; 372 373 case ICMP_TSTAMP: 374 if (icmplen < ICMP_TSLEN) { 375 icmpstat.icps_badlen++; 376 break; 377 } 378 icp->icmp_type = ICMP_TSTAMPREPLY; 379 icp->icmp_rtime = iptime(); 380 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 381 goto reflect; 382 383 case ICMP_MASKREQ: 384 if (icmpmaskrepl == 0) 385 break; 386 /* 387 * We are not able to respond with all ones broadcast 388 * unless we receive it over a point-to-point interface. 389 */ 390 if (icmplen < ICMP_MASKLEN) { 391 icmpstat.icps_badlen++; 392 break; 393 } 394 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 395 in_nullhost(ip->ip_dst)) 396 icmpdst.sin_addr = ip->ip_src; 397 else 398 icmpdst.sin_addr = ip->ip_dst; 399 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 400 m->m_pkthdr.rcvif)); 401 if (ia == 0) 402 break; 403 icp->icmp_type = ICMP_MASKREPLY; 404 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 405 if (in_nullhost(ip->ip_src)) { 406 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 407 ip->ip_src = ia->ia_broadaddr.sin_addr; 408 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 409 ip->ip_src = ia->ia_dstaddr.sin_addr; 410 } 411 reflect: 412 icmpstat.icps_reflect++; 413 icmpstat.icps_outhist[icp->icmp_type]++; 414 icmp_reflect(m); 415 return; 416 417 case ICMP_REDIRECT: 418 if (code > 3) 419 goto badcode; 420 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 421 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 422 icmpstat.icps_badlen++; 423 break; 424 } 425 /* 426 * Short circuit routing redirects to force 427 * immediate change in the kernel's routing 428 * tables. The message is also handed to anyone 429 * listening on a raw socket (e.g. the routing 430 * daemon for use in updating its tables). 431 */ 432 icmpgw.sin_addr = ip->ip_src; 433 icmpdst.sin_addr = icp->icmp_gwaddr; 434 #ifdef ICMPPRINTFS 435 if (icmpprintfs) 436 printf("redirect dst %x to %x\n", icp->icmp_ip.ip_dst, 437 icp->icmp_gwaddr); 438 #endif 439 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 440 rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst), 441 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 442 sintosa(&icmpgw), (struct rtentry **)0); 443 pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc)); 444 break; 445 446 /* 447 * No kernel processing for the following; 448 * just fall through to send to raw listener. 449 */ 450 case ICMP_ECHOREPLY: 451 case ICMP_ROUTERADVERT: 452 case ICMP_ROUTERSOLICIT: 453 case ICMP_TSTAMPREPLY: 454 case ICMP_IREQREPLY: 455 case ICMP_MASKREPLY: 456 default: 457 break; 458 } 459 460 raw: 461 rip_input(m); 462 return; 463 464 freeit: 465 m_freem(m); 466 } 467 468 /* 469 * Reflect the ip packet back to the source 470 */ 471 void 472 icmp_reflect(m) 473 struct mbuf *m; 474 { 475 register struct ip *ip = mtod(m, struct ip *); 476 register struct in_ifaddr *ia; 477 register struct ifaddr *ifa; 478 struct in_addr t; 479 struct mbuf *opts = 0; 480 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 481 482 if (!in_canforward(ip->ip_src) && 483 ((ip->ip_src.s_addr & IN_CLASSA_NET) != 484 htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 485 m_freem(m); /* Bad return address */ 486 goto done; /* ip_output() will check for broadcast */ 487 } 488 t = ip->ip_dst; 489 ip->ip_dst = ip->ip_src; 490 /* 491 * If the incoming packet was addressed directly to us, 492 * use dst as the src for the reply. Otherwise (broadcast 493 * or anonymous), use the address which corresponds 494 * to the incoming interface. 495 */ 496 INADDR_TO_IA(t, ia); 497 if (ia == NULL && (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 498 for (ifa = m->m_pkthdr.rcvif->if_addrlist.tqh_first; 499 ifa != NULL; ifa = ifa->ifa_list.tqe_next) { 500 if (ifa->ifa_addr->sa_family != AF_INET) 501 continue; 502 ia = ifatoia(ifa); 503 if (in_hosteq(t, ia->ia_broadaddr.sin_addr)) 504 break; 505 } 506 } 507 508 icmpdst.sin_addr = t; 509 if (ia == (struct in_ifaddr *)0) 510 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 511 m->m_pkthdr.rcvif)); 512 /* 513 * The following happens if the packet was not addressed to us, 514 * and was received on an interface with no IP address: 515 * We find the first AF_INET address on the first non-loopback 516 * interface. 517 */ 518 if (ia == (struct in_ifaddr *)0) 519 for (ia = in_ifaddr.tqh_first; ia != NULL; 520 ia = ia->ia_list.tqe_next) { 521 if (ia->ia_ifp->if_flags & IFF_LOOPBACK) 522 continue; 523 break; 524 } 525 /* 526 * If we still didn't find an address, punt. We could have an 527 * interface up (and receiving packets) with no address. 528 */ 529 if (ia == (struct in_ifaddr *)0) { 530 m_freem(m); 531 goto done; 532 } 533 534 t = ia->ia_addr.sin_addr; 535 ip->ip_src = t; 536 ip->ip_ttl = MAXTTL; 537 538 if (optlen > 0) { 539 register u_char *cp; 540 int opt, cnt; 541 u_int len; 542 543 /* 544 * Retrieve any source routing from the incoming packet; 545 * add on any record-route or timestamp options. 546 */ 547 cp = (u_char *) (ip + 1); 548 if ((opts = ip_srcroute()) == 0 && 549 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 550 opts->m_len = sizeof(struct in_addr); 551 *mtod(opts, struct in_addr *) = zeroin_addr; 552 } 553 if (opts) { 554 #ifdef ICMPPRINTFS 555 if (icmpprintfs) 556 printf("icmp_reflect optlen %d rt %d => ", 557 optlen, opts->m_len); 558 #endif 559 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 560 opt = cp[IPOPT_OPTVAL]; 561 if (opt == IPOPT_EOL) 562 break; 563 if (opt == IPOPT_NOP) 564 len = 1; 565 else { 566 len = cp[IPOPT_OLEN]; 567 if (len <= 0 || len > cnt) 568 break; 569 } 570 /* 571 * Should check for overflow, but it "can't happen" 572 */ 573 if (opt == IPOPT_RR || opt == IPOPT_TS || 574 opt == IPOPT_SECURITY) { 575 bcopy((caddr_t)cp, 576 mtod(opts, caddr_t) + opts->m_len, len); 577 opts->m_len += len; 578 } 579 } 580 /* Terminate & pad, if necessary */ 581 if ((cnt = opts->m_len % 4) != 0) { 582 for (; cnt < 4; cnt++) { 583 *(mtod(opts, caddr_t) + opts->m_len) = 584 IPOPT_EOL; 585 opts->m_len++; 586 } 587 } 588 #ifdef ICMPPRINTFS 589 if (icmpprintfs) 590 printf("%d\n", opts->m_len); 591 #endif 592 } 593 /* 594 * Now strip out original options by copying rest of first 595 * mbuf's data back, and adjust the IP length. 596 */ 597 ip->ip_len -= optlen; 598 ip->ip_hl = sizeof(struct ip) >> 2; 599 m->m_len -= optlen; 600 if (m->m_flags & M_PKTHDR) 601 m->m_pkthdr.len -= optlen; 602 optlen += sizeof(struct ip); 603 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 604 (unsigned)(m->m_len - sizeof(struct ip))); 605 } 606 m->m_flags &= ~(M_BCAST|M_MCAST); 607 icmp_send(m, opts); 608 done: 609 if (opts) 610 (void)m_free(opts); 611 } 612 613 /* 614 * Send an icmp packet back to the ip level, 615 * after supplying a checksum. 616 */ 617 void 618 icmp_send(m, opts) 619 register struct mbuf *m; 620 struct mbuf *opts; 621 { 622 register struct ip *ip = mtod(m, struct ip *); 623 register int hlen; 624 register struct icmp *icp; 625 626 hlen = ip->ip_hl << 2; 627 m->m_data += hlen; 628 m->m_len -= hlen; 629 icp = mtod(m, struct icmp *); 630 icp->icmp_cksum = 0; 631 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 632 m->m_data -= hlen; 633 m->m_len += hlen; 634 #ifdef ICMPPRINTFS 635 if (icmpprintfs) 636 printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src); 637 #endif 638 (void) ip_output(m, opts, NULL, 0, NULL); 639 } 640 641 n_time 642 iptime() 643 { 644 struct timeval atv; 645 u_long t; 646 647 microtime(&atv); 648 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 649 return (htonl(t)); 650 } 651 652 int 653 icmp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 654 int *name; 655 u_int namelen; 656 void *oldp; 657 size_t *oldlenp; 658 void *newp; 659 size_t newlen; 660 { 661 662 /* All sysctl names at this level are terminal. */ 663 if (namelen != 1) 664 return (ENOTDIR); 665 666 switch (name[0]) { 667 case ICMPCTL_MASKREPL: 668 return (sysctl_int(oldp, oldlenp, newp, newlen, &icmpmaskrepl)); 669 default: 670 return (ENOPROTOOPT); 671 } 672 /* NOTREACHED */ 673 } 674 675 static void 676 icmp_mtudisc(icp) 677 struct icmp *icp; 678 { 679 struct rtentry *rt; 680 struct sockaddr *dst = sintosa(&icmpsrc); 681 u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */ 682 int error; 683 684 /* Table of common MTUs: */ 685 686 static u_long mtu_table[] = {65535, 65280, 32000, 17914, 9180, 8166, 687 4352, 2002, 1492, 1006, 508, 296, 68, 0}; 688 689 rt = rtalloc1(dst, 1); 690 if (rt == 0) 691 return; 692 693 /* If we didn't get a host route, allocate one */ 694 695 if ((rt->rt_flags & RTF_HOST) == 0) { 696 struct rtentry *nrt; 697 698 error = rtrequest((int) RTM_ADD, dst, 699 (struct sockaddr *) rt->rt_gateway, 700 (struct sockaddr *) 0, 701 RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt); 702 if (error) { 703 rtfree(rt); 704 rtfree(nrt); 705 return; 706 } 707 nrt->rt_rmx = rt->rt_rmx; 708 rtfree(rt); 709 rt = nrt; 710 } 711 error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q); 712 if (error) { 713 rtfree(rt); 714 return; 715 } 716 717 if (mtu == 0) { 718 int i = 0; 719 720 mtu = icp->icmp_ip.ip_len; /* NTOHS happened in deliver: */ 721 /* Some 4.2BSD-based routers incorrectly adjust the ip_len */ 722 if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0) 723 mtu -= (icp->icmp_ip.ip_hl << 2); 724 725 /* If we still can't guess a value, try the route */ 726 727 if (mtu == 0) { 728 mtu = rt->rt_rmx.rmx_mtu; 729 730 /* If no route mtu, default to the interface mtu */ 731 732 if (mtu == 0) 733 mtu = rt->rt_ifp->if_mtu; 734 } 735 736 for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++) 737 if (mtu > mtu_table[i]) { 738 mtu = mtu_table[i]; 739 break; 740 } 741 } 742 743 /* 744 * XXX: RTV_MTU is overloaded, since the admin can set it 745 * to turn off PMTU for a route, and the kernel can 746 * set it to indicate a serious problem with PMTU 747 * on a route. We should be using a separate flag 748 * for the kernel to indicate this. 749 */ 750 751 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 752 if (mtu < 296 || mtu > rt->rt_ifp->if_mtu) 753 rt->rt_rmx.rmx_locks |= RTV_MTU; 754 else if (rt->rt_rmx.rmx_mtu > mtu || 755 rt->rt_rmx.rmx_mtu == 0) 756 rt->rt_rmx.rmx_mtu = mtu; 757 } 758 759 if (rt) 760 rtfree(rt); 761 } 762 763 764 static void 765 icmp_mtudisc_timeout(rt, r) 766 struct rtentry *rt; 767 struct rttimer *r; 768 { 769 if (rt == NULL) 770 panic("icmp_mtudisc_timeout: bad route to timeout"); 771 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 772 (RTF_DYNAMIC | RTF_HOST)) { 773 rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt), 774 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 775 } else { 776 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 777 rt->rt_rmx.rmx_mtu = 0; 778 } 779 } 780 } 781
Indexes created Wed Sep 24 05:09:52 GMT 2025