ip_icmp.c revision 1.30.4.1
1 /* $NetBSD: ip_icmp.c,v 1.30.4.1 1998/12/11 04:53:08 kenh Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1988, 1993 5 * The Regents of the University of California. 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 36 */ 37 38 /*- 39 * Copyright (c) 1998 The NetBSD Foundation, Inc. 40 * All rights reserved. 41 * 42 * This code is derived from software contributed to The NetBSD Foundation 43 * by Public Access Networks Corporation ("Panix"). It was developed under 44 * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon. 45 * 46 * Redistribution and use in source and binary forms, with or without 47 * modification, are permitted provided that the following conditions 48 * are met: 49 * 1. Redistributions of source code must retain the above copyright 50 * notice, this list of conditions and the following disclaimer. 51 * 2. Redistributions in binary form must reproduce the above copyright 52 * notice, this list of conditions and the following disclaimer in the 53 * documentation and/or other materials provided with the distribution. 54 * 3. All advertising materials mentioning features or use of this software 55 * must display the following acknowledgement: 56 * This product includes software developed by the NetBSD 57 * Foundation, Inc. and its contributors. 58 * 4. Neither the name of The NetBSD Foundation nor the names of its 59 * contributors may be used to endorse or promote products derived 60 * from this software without specific prior written permission. 61 * 62 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 63 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 64 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 65 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 66 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 67 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 68 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 69 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 70 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 71 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 72 * POSSIBILITY OF SUCH DAMAGE. 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 = 0; 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 if (ia) 415 ifa_delref(&ia->ia_ifa); 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 = 0; 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), s; 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 s = splimp(); 498 INADDR_TO_IA(t, ia); 499 if (ia == NULL && (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 500 for (ifa = m->m_pkthdr.rcvif->if_addrlist.tqh_first; 501 ifa != NULL; ifa = ifa->ifa_list.tqe_next) { 502 if (ifa->ifa_addr->sa_family != AF_INET) 503 continue; 504 ia = ifatoia(ifa); 505 if (in_hosteq(t, ia->ia_broadaddr.sin_addr)) { 506 ifa_addref(&ia->ia_ifa); 507 break; 508 } 509 } 510 } 511 512 icmpdst.sin_addr = t; 513 if (ia == (struct in_ifaddr *)0) 514 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 515 m->m_pkthdr.rcvif)); 516 /* 517 * The following happens if the packet was not addressed to us, 518 * and was received on an interface with no IP address: 519 * We find the first AF_INET address on the first non-loopback 520 * interface. 521 */ 522 if (ia == (struct in_ifaddr *)0) 523 for (ia = in_ifaddr.tqh_first; ia != NULL; 524 ia = ia->ia_list.tqe_next) { 525 if (ia->ia_ifp->if_flags & IFF_LOOPBACK) 526 continue; 527 t = ia->ia_addr.sin_addr; 528 break; 529 } 530 else { 531 t = ia->ia_addr.sin_addr; 532 ifa_delref(&ia->ia_ifa); 533 } 534 /* 535 * As we only want to copy the sin_addr into t, we don't add 536 * and then delete a reference to the address in the for loop above. 537 * We just directly copy (at splimp). Otherwise, we copy the 538 * address and throw away the reference 539 */ 540 splx(s); 541 ip->ip_src = t; 542 ip->ip_ttl = MAXTTL; 543 544 if (optlen > 0) { 545 register u_char *cp; 546 int opt, cnt; 547 u_int len; 548 549 /* 550 * Retrieve any source routing from the incoming packet; 551 * add on any record-route or timestamp options. 552 */ 553 cp = (u_char *) (ip + 1); 554 if ((opts = ip_srcroute()) == 0 && 555 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 556 opts->m_len = sizeof(struct in_addr); 557 *mtod(opts, struct in_addr *) = zeroin_addr; 558 } 559 if (opts) { 560 #ifdef ICMPPRINTFS 561 if (icmpprintfs) 562 printf("icmp_reflect optlen %d rt %d => ", 563 optlen, opts->m_len); 564 #endif 565 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 566 opt = cp[IPOPT_OPTVAL]; 567 if (opt == IPOPT_EOL) 568 break; 569 if (opt == IPOPT_NOP) 570 len = 1; 571 else { 572 len = cp[IPOPT_OLEN]; 573 if (len <= 0 || len > cnt) 574 break; 575 } 576 /* 577 * Should check for overflow, but it "can't happen" 578 */ 579 if (opt == IPOPT_RR || opt == IPOPT_TS || 580 opt == IPOPT_SECURITY) { 581 bcopy((caddr_t)cp, 582 mtod(opts, caddr_t) + opts->m_len, len); 583 opts->m_len += len; 584 } 585 } 586 /* Terminate & pad, if necessary */ 587 if ((cnt = opts->m_len % 4) != 0) { 588 for (; cnt < 4; cnt++) { 589 *(mtod(opts, caddr_t) + opts->m_len) = 590 IPOPT_EOL; 591 opts->m_len++; 592 } 593 } 594 #ifdef ICMPPRINTFS 595 if (icmpprintfs) 596 printf("%d\n", opts->m_len); 597 #endif 598 } 599 /* 600 * Now strip out original options by copying rest of first 601 * mbuf's data back, and adjust the IP length. 602 */ 603 ip->ip_len -= optlen; 604 ip->ip_hl = sizeof(struct ip) >> 2; 605 m->m_len -= optlen; 606 if (m->m_flags & M_PKTHDR) 607 m->m_pkthdr.len -= optlen; 608 optlen += sizeof(struct ip); 609 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 610 (unsigned)(m->m_len - sizeof(struct ip))); 611 } 612 m->m_flags &= ~(M_BCAST|M_MCAST); 613 icmp_send(m, opts); 614 done: 615 if (opts) 616 (void)m_free(opts); 617 } 618 619 /* 620 * Send an icmp packet back to the ip level, 621 * after supplying a checksum. 622 */ 623 void 624 icmp_send(m, opts) 625 register struct mbuf *m; 626 struct mbuf *opts; 627 { 628 register struct ip *ip = mtod(m, struct ip *); 629 register int hlen; 630 register struct icmp *icp; 631 632 hlen = ip->ip_hl << 2; 633 m->m_data += hlen; 634 m->m_len -= hlen; 635 icp = mtod(m, struct icmp *); 636 icp->icmp_cksum = 0; 637 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 638 m->m_data -= hlen; 639 m->m_len += hlen; 640 #ifdef ICMPPRINTFS 641 if (icmpprintfs) 642 printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src); 643 #endif 644 (void) ip_output(m, opts, NULL, 0, NULL); 645 } 646 647 n_time 648 iptime() 649 { 650 struct timeval atv; 651 u_long t; 652 653 microtime(&atv); 654 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 655 return (htonl(t)); 656 } 657 658 int 659 icmp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 660 int *name; 661 u_int namelen; 662 void *oldp; 663 size_t *oldlenp; 664 void *newp; 665 size_t newlen; 666 { 667 668 /* All sysctl names at this level are terminal. */ 669 if (namelen != 1) 670 return (ENOTDIR); 671 672 switch (name[0]) { 673 case ICMPCTL_MASKREPL: 674 return (sysctl_int(oldp, oldlenp, newp, newlen, &icmpmaskrepl)); 675 default: 676 return (ENOPROTOOPT); 677 } 678 /* NOTREACHED */ 679 } 680 681 static void 682 icmp_mtudisc(icp) 683 struct icmp *icp; 684 { 685 struct rtentry *rt; 686 struct sockaddr *dst = sintosa(&icmpsrc); 687 u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */ 688 int error; 689 690 /* Table of common MTUs: */ 691 692 static u_long mtu_table[] = {65535, 65280, 32000, 17914, 9180, 8166, 693 4352, 2002, 1492, 1006, 508, 296, 68, 0}; 694 695 rt = rtalloc1(dst, 1); 696 if (rt == 0) 697 return; 698 699 /* If we didn't get a host route, allocate one */ 700 701 if ((rt->rt_flags & RTF_HOST) == 0) { 702 struct rtentry *nrt; 703 704 error = rtrequest((int) RTM_ADD, dst, 705 (struct sockaddr *) rt->rt_gateway, 706 (struct sockaddr *) 0, 707 RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt); 708 if (error) { 709 rtfree(rt); 710 rtfree(nrt); 711 return; 712 } 713 nrt->rt_rmx = rt->rt_rmx; 714 rtfree(rt); 715 rt = nrt; 716 } 717 error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q); 718 if (error) { 719 rtfree(rt); 720 return; 721 } 722 723 if (mtu == 0) { 724 int i = 0; 725 726 mtu = icp->icmp_ip.ip_len; /* NTOHS happened in deliver: */ 727 /* Some 4.2BSD-based routers incorrectly adjust the ip_len */ 728 if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0) 729 mtu -= (icp->icmp_ip.ip_hl << 2); 730 731 /* If we still can't guess a value, try the route */ 732 733 if (mtu == 0) { 734 mtu = rt->rt_rmx.rmx_mtu; 735 736 /* If no route mtu, default to the interface mtu */ 737 738 if (mtu == 0) 739 mtu = rt->rt_ifp->if_mtu; 740 } 741 742 for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++) 743 if (mtu > mtu_table[i]) { 744 mtu = mtu_table[i]; 745 break; 746 } 747 } 748 749 /* 750 * XXX: RTV_MTU is overloaded, since the admin can set it 751 * to turn off PMTU for a route, and the kernel can 752 * set it to indicate a serious problem with PMTU 753 * on a route. We should be using a separate flag 754 * for the kernel to indicate this. 755 */ 756 757 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 758 if (mtu < 296 || mtu > rt->rt_ifp->if_mtu) 759 rt->rt_rmx.rmx_locks |= RTV_MTU; 760 else if (rt->rt_rmx.rmx_mtu > mtu || 761 rt->rt_rmx.rmx_mtu == 0) 762 rt->rt_rmx.rmx_mtu = mtu; 763 } 764 765 if (rt) 766 rtfree(rt); 767 } 768 769 770 static void 771 icmp_mtudisc_timeout(rt, r) 772 struct rtentry *rt; 773 struct rttimer *r; 774 { 775 if (rt == NULL) 776 panic("icmp_mtudisc_timeout: bad route to timeout"); 777 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 778 (RTF_DYNAMIC | RTF_HOST)) { 779 rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt), 780 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 781 } else { 782 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 783 rt->rt_rmx.rmx_mtu = 0; 784 } 785 } 786 } 787
Indexes created Fri Oct 03 02:09:57 GMT 2025