ip_icmp.c revision 1.29
1 /* $NetBSD: ip_icmp.c,v 1.29 1998/04/29 03:44:11 kml 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); 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 icp->icmp_code = code; 187 bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen); 188 nip = &icp->icmp_ip; 189 nip->ip_len = htons((u_int16_t)(nip->ip_len + oiplen)); 190 191 /* 192 * Now, copy old ip header (without options) 193 * in front of icmp message. 194 */ 195 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 196 panic("icmp len"); 197 m->m_data -= sizeof(struct ip); 198 m->m_len += sizeof(struct ip); 199 m->m_pkthdr.len = m->m_len; 200 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 201 nip = mtod(m, struct ip *); 202 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); 203 nip->ip_len = m->m_len; 204 nip->ip_hl = sizeof(struct ip) >> 2; 205 nip->ip_p = IPPROTO_ICMP; 206 nip->ip_tos = 0; 207 icmp_reflect(m); 208 209 freeit: 210 m_freem(n); 211 } 212 213 static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; 214 static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; 215 static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; 216 struct sockaddr_in icmpmask = { 8, 0 }; 217 218 /* 219 * Process a received ICMP message. 220 */ 221 void 222 #if __STDC__ 223 icmp_input(struct mbuf *m, ...) 224 #else 225 icmp_input(m, va_alist) 226 struct mbuf *m; 227 va_dcl 228 #endif 229 { 230 register struct icmp *icp; 231 register struct ip *ip = mtod(m, struct ip *); 232 int icmplen = ip->ip_len; 233 register int i; 234 struct in_ifaddr *ia; 235 void *(*ctlfunc) __P((int, struct sockaddr *, void *)); 236 int code; 237 extern u_char ip_protox[]; 238 int hlen; 239 va_list ap; 240 241 va_start(ap, m); 242 hlen = va_arg(ap, int); 243 va_end(ap); 244 245 /* 246 * Locate icmp structure in mbuf, and check 247 * that not corrupted and of at least minimum length. 248 */ 249 #ifdef ICMPPRINTFS 250 if (icmpprintfs) 251 printf("icmp_input from %x to %x, len %d\n", 252 ntohl(ip->ip_src.s_addr), ntohl(ip->ip_dst.s_addr), 253 icmplen); 254 #endif 255 if (icmplen < ICMP_MINLEN) { 256 icmpstat.icps_tooshort++; 257 goto freeit; 258 } 259 i = hlen + min(icmplen, ICMP_ADVLENMIN); 260 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 261 icmpstat.icps_tooshort++; 262 return; 263 } 264 ip = mtod(m, struct ip *); 265 m->m_len -= hlen; 266 m->m_data += hlen; 267 icp = mtod(m, struct icmp *); 268 if (in_cksum(m, icmplen)) { 269 icmpstat.icps_checksum++; 270 goto freeit; 271 } 272 m->m_len += hlen; 273 m->m_data -= hlen; 274 275 #ifdef ICMPPRINTFS 276 /* 277 * Message type specific processing. 278 */ 279 if (icmpprintfs) 280 printf("icmp_input, type %d code %d\n", icp->icmp_type, 281 icp->icmp_code); 282 #endif 283 if (icp->icmp_type > ICMP_MAXTYPE) 284 goto raw; 285 icmpstat.icps_inhist[icp->icmp_type]++; 286 code = icp->icmp_code; 287 switch (icp->icmp_type) { 288 289 case ICMP_UNREACH: 290 switch (code) { 291 case ICMP_UNREACH_NET: 292 case ICMP_UNREACH_HOST: 293 case ICMP_UNREACH_PROTOCOL: 294 case ICMP_UNREACH_PORT: 295 case ICMP_UNREACH_SRCFAIL: 296 code += PRC_UNREACH_NET; 297 break; 298 299 case ICMP_UNREACH_NEEDFRAG: 300 code = PRC_MSGSIZE; 301 break; 302 303 case ICMP_UNREACH_NET_UNKNOWN: 304 case ICMP_UNREACH_NET_PROHIB: 305 case ICMP_UNREACH_TOSNET: 306 code = PRC_UNREACH_NET; 307 break; 308 309 case ICMP_UNREACH_HOST_UNKNOWN: 310 case ICMP_UNREACH_ISOLATED: 311 case ICMP_UNREACH_HOST_PROHIB: 312 case ICMP_UNREACH_TOSHOST: 313 code = PRC_UNREACH_HOST; 314 break; 315 316 default: 317 goto badcode; 318 } 319 goto deliver; 320 321 case ICMP_TIMXCEED: 322 if (code > 1) 323 goto badcode; 324 code += PRC_TIMXCEED_INTRANS; 325 goto deliver; 326 327 case ICMP_PARAMPROB: 328 if (code > 1) 329 goto badcode; 330 code = PRC_PARAMPROB; 331 goto deliver; 332 333 case ICMP_SOURCEQUENCH: 334 if (code) 335 goto badcode; 336 code = PRC_QUENCH; 337 goto deliver; 338 339 deliver: 340 /* 341 * Problem with datagram; advise higher level routines. 342 */ 343 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 344 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 345 icmpstat.icps_badlen++; 346 goto freeit; 347 } 348 if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr)) 349 goto badcode; 350 NTOHS(icp->icmp_ip.ip_len); 351 #ifdef ICMPPRINTFS 352 if (icmpprintfs) 353 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 354 #endif 355 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 356 if (code == PRC_MSGSIZE && ip_mtudisc) 357 icmp_mtudisc(icp); 358 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 359 if (ctlfunc) 360 (*ctlfunc)(code, sintosa(&icmpsrc), &icp->icmp_ip); 361 break; 362 363 badcode: 364 icmpstat.icps_badcode++; 365 break; 366 367 case ICMP_ECHO: 368 icp->icmp_type = ICMP_ECHOREPLY; 369 goto reflect; 370 371 case ICMP_TSTAMP: 372 if (icmplen < ICMP_TSLEN) { 373 icmpstat.icps_badlen++; 374 break; 375 } 376 icp->icmp_type = ICMP_TSTAMPREPLY; 377 icp->icmp_rtime = iptime(); 378 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 379 goto reflect; 380 381 case ICMP_MASKREQ: 382 if (icmpmaskrepl == 0) 383 break; 384 /* 385 * We are not able to respond with all ones broadcast 386 * unless we receive it over a point-to-point interface. 387 */ 388 if (icmplen < ICMP_MASKLEN) { 389 icmpstat.icps_badlen++; 390 break; 391 } 392 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 393 in_nullhost(ip->ip_dst)) 394 icmpdst.sin_addr = ip->ip_src; 395 else 396 icmpdst.sin_addr = ip->ip_dst; 397 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 398 m->m_pkthdr.rcvif)); 399 if (ia == 0) 400 break; 401 icp->icmp_type = ICMP_MASKREPLY; 402 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 403 if (in_nullhost(ip->ip_src)) { 404 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 405 ip->ip_src = ia->ia_broadaddr.sin_addr; 406 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 407 ip->ip_src = ia->ia_dstaddr.sin_addr; 408 } 409 reflect: 410 ip->ip_len += hlen; /* since ip_input deducts this */ 411 icmpstat.icps_reflect++; 412 icmpstat.icps_outhist[icp->icmp_type]++; 413 icmp_reflect(m); 414 return; 415 416 case ICMP_REDIRECT: 417 if (code > 3) 418 goto badcode; 419 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 420 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 421 icmpstat.icps_badlen++; 422 break; 423 } 424 /* 425 * Short circuit routing redirects to force 426 * immediate change in the kernel's routing 427 * tables. The message is also handed to anyone 428 * listening on a raw socket (e.g. the routing 429 * daemon for use in updating its tables). 430 */ 431 icmpgw.sin_addr = ip->ip_src; 432 icmpdst.sin_addr = icp->icmp_gwaddr; 433 #ifdef ICMPPRINTFS 434 if (icmpprintfs) 435 printf("redirect dst %x to %x\n", icp->icmp_ip.ip_dst, 436 icp->icmp_gwaddr); 437 #endif 438 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 439 rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst), 440 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 441 sintosa(&icmpgw), (struct rtentry **)0); 442 pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc)); 443 break; 444 445 /* 446 * No kernel processing for the following; 447 * just fall through to send to raw listener. 448 */ 449 case ICMP_ECHOREPLY: 450 case ICMP_ROUTERADVERT: 451 case ICMP_ROUTERSOLICIT: 452 case ICMP_TSTAMPREPLY: 453 case ICMP_IREQREPLY: 454 case ICMP_MASKREPLY: 455 default: 456 break; 457 } 458 459 raw: 460 rip_input(m); 461 return; 462 463 freeit: 464 m_freem(m); 465 } 466 467 /* 468 * Reflect the ip packet back to the source 469 */ 470 void 471 icmp_reflect(m) 472 struct mbuf *m; 473 { 474 register struct ip *ip = mtod(m, struct ip *); 475 register struct in_ifaddr *ia; 476 register struct ifaddr *ifa; 477 struct in_addr t; 478 struct mbuf *opts = 0; 479 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 480 481 if (!in_canforward(ip->ip_src) && 482 ((ip->ip_src.s_addr & IN_CLASSA_NET) != 483 htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 484 m_freem(m); /* Bad return address */ 485 goto done; /* ip_output() will check for broadcast */ 486 } 487 t = ip->ip_dst; 488 ip->ip_dst = ip->ip_src; 489 /* 490 * If the incoming packet was addressed directly to us, 491 * use dst as the src for the reply. Otherwise (broadcast 492 * or anonymous), use the address which corresponds 493 * to the incoming interface. 494 */ 495 INADDR_TO_IA(t, ia); 496 if (ia == NULL && (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 497 for (ifa = m->m_pkthdr.rcvif->if_addrlist.tqh_first; 498 ifa != NULL; ifa = ifa->ifa_list.tqe_next) { 499 if (ifa->ifa_addr->sa_family != AF_INET) 500 continue; 501 ia = ifatoia(ifa); 502 if (in_hosteq(t, ia->ia_broadaddr.sin_addr)) 503 break; 504 } 505 } 506 507 icmpdst.sin_addr = t; 508 if (ia == (struct in_ifaddr *)0) 509 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 510 m->m_pkthdr.rcvif)); 511 /* 512 * The following happens if the packet was not addressed to us, 513 * and was received on an interface with no IP address: 514 * We find the first AF_INET address on the first non-loopback 515 * interface. 516 */ 517 if (ia == (struct in_ifaddr *)0) 518 for (ia = in_ifaddr.tqh_first; ia != NULL; 519 ia = ia->ia_list.tqe_next) { 520 if (ia->ia_ifp->if_flags & IFF_LOOPBACK) 521 continue; 522 break; 523 } 524 t = ia->ia_addr.sin_addr; 525 ip->ip_src = t; 526 ip->ip_ttl = MAXTTL; 527 528 if (optlen > 0) { 529 register u_char *cp; 530 int opt, cnt; 531 u_int len; 532 533 /* 534 * Retrieve any source routing from the incoming packet; 535 * add on any record-route or timestamp options. 536 */ 537 cp = (u_char *) (ip + 1); 538 if ((opts = ip_srcroute()) == 0 && 539 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 540 opts->m_len = sizeof(struct in_addr); 541 *mtod(opts, struct in_addr *) = zeroin_addr; 542 } 543 if (opts) { 544 #ifdef ICMPPRINTFS 545 if (icmpprintfs) 546 printf("icmp_reflect optlen %d rt %d => ", 547 optlen, opts->m_len); 548 #endif 549 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 550 opt = cp[IPOPT_OPTVAL]; 551 if (opt == IPOPT_EOL) 552 break; 553 if (opt == IPOPT_NOP) 554 len = 1; 555 else { 556 len = cp[IPOPT_OLEN]; 557 if (len <= 0 || len > cnt) 558 break; 559 } 560 /* 561 * Should check for overflow, but it "can't happen" 562 */ 563 if (opt == IPOPT_RR || opt == IPOPT_TS || 564 opt == IPOPT_SECURITY) { 565 bcopy((caddr_t)cp, 566 mtod(opts, caddr_t) + opts->m_len, len); 567 opts->m_len += len; 568 } 569 } 570 /* Terminate & pad, if necessary */ 571 if ((cnt = opts->m_len % 4) != 0) { 572 for (; cnt < 4; cnt++) { 573 *(mtod(opts, caddr_t) + opts->m_len) = 574 IPOPT_EOL; 575 opts->m_len++; 576 } 577 } 578 #ifdef ICMPPRINTFS 579 if (icmpprintfs) 580 printf("%d\n", opts->m_len); 581 #endif 582 } 583 /* 584 * Now strip out original options by copying rest of first 585 * mbuf's data back, and adjust the IP length. 586 */ 587 ip->ip_len -= optlen; 588 ip->ip_hl = sizeof(struct ip) >> 2; 589 m->m_len -= optlen; 590 if (m->m_flags & M_PKTHDR) 591 m->m_pkthdr.len -= optlen; 592 optlen += sizeof(struct ip); 593 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 594 (unsigned)(m->m_len - sizeof(struct ip))); 595 } 596 m->m_flags &= ~(M_BCAST|M_MCAST); 597 icmp_send(m, opts); 598 done: 599 if (opts) 600 (void)m_free(opts); 601 } 602 603 /* 604 * Send an icmp packet back to the ip level, 605 * after supplying a checksum. 606 */ 607 void 608 icmp_send(m, opts) 609 register struct mbuf *m; 610 struct mbuf *opts; 611 { 612 register struct ip *ip = mtod(m, struct ip *); 613 register int hlen; 614 register struct icmp *icp; 615 616 hlen = ip->ip_hl << 2; 617 m->m_data += hlen; 618 m->m_len -= hlen; 619 icp = mtod(m, struct icmp *); 620 icp->icmp_cksum = 0; 621 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 622 m->m_data -= hlen; 623 m->m_len += hlen; 624 #ifdef ICMPPRINTFS 625 if (icmpprintfs) 626 printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src); 627 #endif 628 (void) ip_output(m, opts, NULL, 0, NULL); 629 } 630 631 n_time 632 iptime() 633 { 634 struct timeval atv; 635 u_long t; 636 637 microtime(&atv); 638 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 639 return (htonl(t)); 640 } 641 642 int 643 icmp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 644 int *name; 645 u_int namelen; 646 void *oldp; 647 size_t *oldlenp; 648 void *newp; 649 size_t newlen; 650 { 651 652 /* All sysctl names at this level are terminal. */ 653 if (namelen != 1) 654 return (ENOTDIR); 655 656 switch (name[0]) { 657 case ICMPCTL_MASKREPL: 658 return (sysctl_int(oldp, oldlenp, newp, newlen, &icmpmaskrepl)); 659 default: 660 return (ENOPROTOOPT); 661 } 662 /* NOTREACHED */ 663 } 664 665 static void 666 icmp_mtudisc(icp) 667 struct icmp *icp; 668 { 669 struct rtentry *rt; 670 struct sockaddr *dst = sintosa(&icmpsrc); 671 u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */ 672 int error; 673 674 /* Table of common MTUs: */ 675 676 static u_long mtu_table[] = {65535, 65280, 32000, 17914, 9180, 8166, 677 4352, 2002, 1492, 1006, 508, 296, 68, 0}; 678 679 rt = rtalloc1(dst, 1); 680 if (rt == 0) 681 return; 682 683 /* If we didn't get a host route, allocate one */ 684 685 if ((rt->rt_flags & RTF_HOST) == 0) { 686 struct rtentry *nrt; 687 688 error = rtrequest((int) RTM_ADD, dst, 689 (struct sockaddr *) rt->rt_gateway, 690 (struct sockaddr *) 0, 691 RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt); 692 if (error) { 693 rtfree(rt); 694 rtfree(nrt); 695 return; 696 } 697 nrt->rt_rmx = rt->rt_rmx; 698 rtfree(rt); 699 rt = nrt; 700 } 701 error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q); 702 if (error) { 703 rtfree(rt); 704 return; 705 } 706 707 if (mtu == 0) { 708 int i = 0; 709 710 mtu = icp->icmp_ip.ip_len; /* NTOHS happened in deliver: */ 711 /* Some 4.2BSD-based routers incorrectly adjust the ip_len */ 712 if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0) 713 mtu -= (icp->icmp_ip.ip_hl << 2); 714 715 /* If we still can't guess a value, try the route */ 716 717 if (mtu == 0) { 718 mtu = rt->rt_rmx.rmx_mtu; 719 720 /* If no route mtu, default to the interface mtu */ 721 722 if (mtu == 0) 723 mtu = rt->rt_ifp->if_mtu; 724 } 725 726 for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++) 727 if (mtu > mtu_table[i]) { 728 mtu = mtu_table[i]; 729 break; 730 } 731 } 732 733 /* 734 * XXX: RTV_MTU is overloaded, since the admin can set it 735 * to turn off PMTU for a route, and the kernel can 736 * set it to indicate a serious problem with PMTU 737 * on a route. We should be using a separate flag 738 * for the kernel to indicate this. 739 */ 740 741 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 742 if (mtu < 296 || mtu > rt->rt_ifp->if_mtu) 743 rt->rt_rmx.rmx_locks |= RTV_MTU; 744 else if (rt->rt_rmx.rmx_mtu > mtu || 745 rt->rt_rmx.rmx_mtu == 0) 746 rt->rt_rmx.rmx_mtu = mtu; 747 } 748 749 if (rt) 750 rtfree(rt); 751 } 752 753 754 static void 755 icmp_mtudisc_timeout(rt, r) 756 struct rtentry *rt; 757 struct rttimer *r; 758 { 759 if (rt == NULL) 760 panic("icmp_mtudisc_timeout: bad route to timeout"); 761 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 762 (RTF_DYNAMIC | RTF_HOST)) { 763 rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt), 764 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 765 } else { 766 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 767 rt->rt_rmx.rmx_mtu = 0; 768 } 769 } 770 } 771
Indexes created Tue Sep 23 22:09:46 GMT 2025