ip_icmp.c revision 1.36.6.1
1 /* $NetBSD: ip_icmp.c,v 1.36.6.1 1999/06/28 06:37:00 itojun 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) 1995, 1996, 1997, and 1998 WIDE Project. 42 * 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. Neither the name of the project nor the names of its contributors 53 * may be used to endorse or promote products derived from this software 54 * without specific prior written permission. 55 * 56 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 57 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 58 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 59 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 60 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 61 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 62 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 63 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 64 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 65 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 66 * SUCH DAMAGE. 67 */ 68 69 /* 70 * Copyright (c) 1982, 1986, 1988, 1993 71 * The Regents of the University of California. All rights reserved. 72 * 73 * Redistribution and use in source and binary forms, with or without 74 * modification, are permitted provided that the following conditions 75 * are met: 76 * 1. Redistributions of source code must retain the above copyright 77 * notice, this list of conditions and the following disclaimer. 78 * 2. Redistributions in binary form must reproduce the above copyright 79 * notice, this list of conditions and the following disclaimer in the 80 * documentation and/or other materials provided with the distribution. 81 * 3. All advertising materials mentioning features or use of this software 82 * must display the following acknowledgement: 83 * This product includes software developed by the University of 84 * California, Berkeley and its contributors. 85 * 4. Neither the name of the University nor the names of its contributors 86 * may be used to endorse or promote products derived from this software 87 * without specific prior written permission. 88 * 89 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 90 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 91 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 92 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 93 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 94 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 95 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 96 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 97 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 98 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 99 * SUCH DAMAGE. 100 * 101 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 102 */ 103 104 #include <sys/param.h> 105 #include <sys/systm.h> 106 #include <sys/malloc.h> 107 #include <sys/mbuf.h> 108 #include <sys/protosw.h> 109 #include <sys/socket.h> 110 #include <sys/time.h> 111 #include <sys/kernel.h> 112 #include <sys/proc.h> 113 114 #include <vm/vm.h> 115 #include <sys/sysctl.h> 116 117 #include <net/if.h> 118 #include <net/route.h> 119 120 #include <netinet/in.h> 121 #include <netinet/in_systm.h> 122 #include <netinet/in_var.h> 123 #include <netinet/ip.h> 124 #include <netinet/ip_icmp.h> 125 #include <netinet/ip_var.h> 126 #include <netinet/icmp_var.h> 127 128 #ifdef IPSEC 129 #include <netinet6/ipsec.h> 130 #include <netkey/key.h> 131 #include <netkey/key_debug.h> 132 #endif 133 134 #include <machine/stdarg.h> 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 #ifdef ICMPPRINTFS 144 int icmpprintfs = 0; 145 #endif 146 147 #if 0 148 static int ip_next_mtu __P((int, int)); 149 #else 150 /*static*/ int ip_next_mtu __P((int, int)); 151 #endif 152 153 extern struct protosw inetsw[]; 154 155 static void icmp_mtudisc __P((struct icmp *)); 156 static void icmp_mtudisc_timeout __P((struct rtentry *, struct rttimer *)); 157 158 /* 159 * Generate an error packet of type error 160 * in response to bad packet ip. 161 */ 162 void 163 icmp_error(n, type, code, dest, destifp) 164 struct mbuf *n; 165 int type, code; 166 n_long dest; 167 struct ifnet *destifp; 168 { 169 register struct ip *oip = mtod(n, struct ip *), *nip; 170 register unsigned oiplen = oip->ip_hl << 2; 171 register struct icmp *icp; 172 register struct mbuf *m; 173 unsigned icmplen; 174 175 #ifdef ICMPPRINTFS 176 if (icmpprintfs) 177 printf("icmp_error(%x, %d, %d)\n", oip, type, code); 178 #endif 179 if (type != ICMP_REDIRECT) 180 icmpstat.icps_error++; 181 /* 182 * Don't send error if not the first fragment of message. 183 * Don't error if the old packet protocol was ICMP 184 * error message, only known informational types. 185 */ 186 if (oip->ip_off &~ (IP_MF|IP_DF)) 187 goto freeit; 188 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 189 n->m_len >= oiplen + ICMP_MINLEN && 190 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { 191 icmpstat.icps_oldicmp++; 192 goto freeit; 193 } 194 /* Don't send error in response to a multicast or broadcast packet */ 195 if (n->m_flags & (M_BCAST|M_MCAST)) 196 goto freeit; 197 /* 198 * First, formulate icmp message 199 */ 200 m = m_gethdr(M_DONTWAIT, MT_HEADER); 201 if (m == NULL) 202 goto freeit; 203 icmplen = oiplen + min(8, oip->ip_len - oiplen); 204 m->m_len = icmplen + ICMP_MINLEN; 205 MH_ALIGN(m, m->m_len); 206 icp = mtod(m, struct icmp *); 207 if ((u_int)type > ICMP_MAXTYPE) 208 panic("icmp_error"); 209 icmpstat.icps_outhist[type]++; 210 icp->icmp_type = type; 211 if (type == ICMP_REDIRECT) 212 icp->icmp_gwaddr.s_addr = dest; 213 else { 214 icp->icmp_void = 0; 215 /* 216 * The following assignments assume an overlay with the 217 * zeroed icmp_void field. 218 */ 219 if (type == ICMP_PARAMPROB) { 220 icp->icmp_pptr = code; 221 code = 0; 222 } else if (type == ICMP_UNREACH && 223 code == ICMP_UNREACH_NEEDFRAG && destifp) 224 icp->icmp_nextmtu = htons(destifp->if_mtu); 225 } 226 227 HTONS(oip->ip_off); 228 HTONS(oip->ip_len); 229 icp->icmp_code = code; 230 bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen); 231 nip = &icp->icmp_ip; 232 233 /* 234 * Now, copy old ip header (without options) 235 * in front of icmp message. 236 */ 237 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 238 panic("icmp len"); 239 m->m_data -= sizeof(struct ip); 240 m->m_len += sizeof(struct ip); 241 m->m_pkthdr.len = m->m_len; 242 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 243 nip = mtod(m, struct ip *); 244 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); 245 nip->ip_len = m->m_len; 246 nip->ip_hl = sizeof(struct ip) >> 2; 247 nip->ip_p = IPPROTO_ICMP; 248 nip->ip_tos = 0; 249 icmp_reflect(m); 250 251 freeit: 252 m_freem(n); 253 } 254 255 static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; 256 static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; 257 static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; 258 struct sockaddr_in icmpmask = { 8, 0 }; 259 260 /* 261 * Process a received ICMP message. 262 */ 263 void 264 #if __STDC__ 265 icmp_input(struct mbuf *m, ...) 266 #else 267 icmp_input(m, va_alist) 268 struct mbuf *m; 269 va_dcl 270 #endif 271 { 272 int proto; 273 register struct icmp *icp; 274 register struct ip *ip = mtod(m, struct ip *); 275 int icmplen; 276 register int i; 277 struct in_ifaddr *ia; 278 void *(*ctlfunc) __P((int, struct sockaddr *, void *)); 279 int code; 280 extern u_char ip_protox[]; 281 int hlen; 282 va_list ap; 283 284 va_start(ap, m); 285 hlen = va_arg(ap, int); 286 proto = va_arg(ap, int); 287 va_end(ap); 288 289 /* 290 * Locate icmp structure in mbuf, and check 291 * that not corrupted and of at least minimum length. 292 */ 293 icmplen = ip->ip_len - hlen; 294 #ifdef ICMPPRINTFS 295 if (icmpprintfs) 296 printf("icmp_input from %x to %x, len %d\n", 297 ntohl(ip->ip_src.s_addr), ntohl(ip->ip_dst.s_addr), 298 icmplen); 299 #endif 300 if (icmplen < ICMP_MINLEN) { 301 icmpstat.icps_tooshort++; 302 goto freeit; 303 } 304 i = hlen + min(icmplen, ICMP_ADVLENMIN); 305 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 306 icmpstat.icps_tooshort++; 307 return; 308 } 309 ip = mtod(m, struct ip *); 310 m->m_len -= hlen; 311 m->m_data += hlen; 312 icp = mtod(m, struct icmp *); 313 if (in_cksum(m, icmplen)) { 314 icmpstat.icps_checksum++; 315 goto freeit; 316 } 317 m->m_len += hlen; 318 m->m_data -= hlen; 319 320 #ifdef ICMPPRINTFS 321 /* 322 * Message type specific processing. 323 */ 324 if (icmpprintfs) 325 printf("icmp_input, type %d code %d\n", icp->icmp_type, 326 icp->icmp_code); 327 #endif 328 #ifdef IPSEC 329 /* drop it if it does not match the policy */ 330 if (ipsec4_in_reject(m, NULL)) { 331 ipsecstat.in_polvio++; 332 goto freeit; 333 } 334 #endif 335 if (icp->icmp_type > ICMP_MAXTYPE) 336 goto raw; 337 icmpstat.icps_inhist[icp->icmp_type]++; 338 code = icp->icmp_code; 339 switch (icp->icmp_type) { 340 341 case ICMP_UNREACH: 342 switch (code) { 343 case ICMP_UNREACH_NET: 344 case ICMP_UNREACH_HOST: 345 case ICMP_UNREACH_PROTOCOL: 346 case ICMP_UNREACH_PORT: 347 case ICMP_UNREACH_SRCFAIL: 348 code += PRC_UNREACH_NET; 349 break; 350 351 case ICMP_UNREACH_NEEDFRAG: 352 code = PRC_MSGSIZE; 353 break; 354 355 case ICMP_UNREACH_NET_UNKNOWN: 356 case ICMP_UNREACH_NET_PROHIB: 357 case ICMP_UNREACH_TOSNET: 358 code = PRC_UNREACH_NET; 359 break; 360 361 case ICMP_UNREACH_HOST_UNKNOWN: 362 case ICMP_UNREACH_ISOLATED: 363 case ICMP_UNREACH_HOST_PROHIB: 364 case ICMP_UNREACH_TOSHOST: 365 code = PRC_UNREACH_HOST; 366 break; 367 368 default: 369 goto badcode; 370 } 371 goto deliver; 372 373 case ICMP_TIMXCEED: 374 if (code > 1) 375 goto badcode; 376 code += PRC_TIMXCEED_INTRANS; 377 goto deliver; 378 379 case ICMP_PARAMPROB: 380 if (code > 1) 381 goto badcode; 382 code = PRC_PARAMPROB; 383 goto deliver; 384 385 case ICMP_SOURCEQUENCH: 386 if (code) 387 goto badcode; 388 code = PRC_QUENCH; 389 goto deliver; 390 391 deliver: 392 /* 393 * Problem with datagram; advise higher level routines. 394 */ 395 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 396 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 397 icmpstat.icps_badlen++; 398 goto freeit; 399 } 400 if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr)) 401 goto badcode; 402 NTOHS(icp->icmp_ip.ip_len); 403 #ifdef ICMPPRINTFS 404 if (icmpprintfs) 405 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 406 #endif 407 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 408 if (code == PRC_MSGSIZE && ip_mtudisc) 409 icmp_mtudisc(icp); 410 /* 411 * XXX if the packet contains [IPv4 AH TCP], we can't make a 412 * notification to TCP layer. 413 */ 414 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 415 if (ctlfunc) 416 (*ctlfunc)(code, sintosa(&icmpsrc), &icp->icmp_ip); 417 break; 418 419 badcode: 420 icmpstat.icps_badcode++; 421 break; 422 423 case ICMP_ECHO: 424 icp->icmp_type = ICMP_ECHOREPLY; 425 goto reflect; 426 427 case ICMP_TSTAMP: 428 if (icmplen < ICMP_TSLEN) { 429 icmpstat.icps_badlen++; 430 break; 431 } 432 icp->icmp_type = ICMP_TSTAMPREPLY; 433 icp->icmp_rtime = iptime(); 434 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 435 goto reflect; 436 437 case ICMP_MASKREQ: 438 if (icmpmaskrepl == 0) 439 break; 440 /* 441 * We are not able to respond with all ones broadcast 442 * unless we receive it over a point-to-point interface. 443 */ 444 if (icmplen < ICMP_MASKLEN) { 445 icmpstat.icps_badlen++; 446 break; 447 } 448 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 449 in_nullhost(ip->ip_dst)) 450 icmpdst.sin_addr = ip->ip_src; 451 else 452 icmpdst.sin_addr = ip->ip_dst; 453 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 454 m->m_pkthdr.rcvif)); 455 if (ia == 0) 456 break; 457 icp->icmp_type = ICMP_MASKREPLY; 458 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 459 if (in_nullhost(ip->ip_src)) { 460 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 461 ip->ip_src = ia->ia_broadaddr.sin_addr; 462 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 463 ip->ip_src = ia->ia_dstaddr.sin_addr; 464 } 465 reflect: 466 icmpstat.icps_reflect++; 467 icmpstat.icps_outhist[icp->icmp_type]++; 468 icmp_reflect(m); 469 return; 470 471 case ICMP_REDIRECT: 472 if (code > 3) 473 goto badcode; 474 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 475 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 476 icmpstat.icps_badlen++; 477 break; 478 } 479 /* 480 * Short circuit routing redirects to force 481 * immediate change in the kernel's routing 482 * tables. The message is also handed to anyone 483 * listening on a raw socket (e.g. the routing 484 * daemon for use in updating its tables). 485 */ 486 icmpgw.sin_addr = ip->ip_src; 487 icmpdst.sin_addr = icp->icmp_gwaddr; 488 #ifdef ICMPPRINTFS 489 if (icmpprintfs) 490 printf("redirect dst %x to %x\n", icp->icmp_ip.ip_dst, 491 icp->icmp_gwaddr); 492 #endif 493 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 494 rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst), 495 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 496 sintosa(&icmpgw), (struct rtentry **)0); 497 pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc)); 498 #ifdef IPSEC 499 key_sa_routechange((struct sockaddr *)&icmpsrc); 500 #endif 501 break; 502 503 /* 504 * No kernel processing for the following; 505 * just fall through to send to raw listener. 506 */ 507 case ICMP_ECHOREPLY: 508 case ICMP_ROUTERADVERT: 509 case ICMP_ROUTERSOLICIT: 510 case ICMP_TSTAMPREPLY: 511 case ICMP_IREQREPLY: 512 case ICMP_MASKREPLY: 513 default: 514 break; 515 } 516 517 raw: 518 rip_input(m, hlen, proto); 519 return; 520 521 freeit: 522 m_freem(m); 523 return; 524 } 525 526 /* 527 * Reflect the ip packet back to the source 528 */ 529 void 530 icmp_reflect(m) 531 struct mbuf *m; 532 { 533 register struct ip *ip = mtod(m, struct ip *); 534 register struct in_ifaddr *ia; 535 register struct ifaddr *ifa; 536 struct in_addr t; 537 struct mbuf *opts = 0; 538 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 539 540 if (!in_canforward(ip->ip_src) && 541 ((ip->ip_src.s_addr & IN_CLASSA_NET) != 542 htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 543 m_freem(m); /* Bad return address */ 544 goto done; /* ip_output() will check for broadcast */ 545 } 546 t = ip->ip_dst; 547 ip->ip_dst = ip->ip_src; 548 /* 549 * If the incoming packet was addressed directly to us, 550 * use dst as the src for the reply. Otherwise (broadcast 551 * or anonymous), use the address which corresponds 552 * to the incoming interface. 553 */ 554 INADDR_TO_IA(t, ia); 555 if (ia == NULL && (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 556 for (ifa = m->m_pkthdr.rcvif->if_addrlist.tqh_first; 557 ifa != NULL; ifa = ifa->ifa_list.tqe_next) { 558 if (ifa->ifa_addr->sa_family != AF_INET) 559 continue; 560 ia = ifatoia(ifa); 561 if (in_hosteq(t, ia->ia_broadaddr.sin_addr)) 562 break; 563 } 564 } 565 566 icmpdst.sin_addr = t; 567 if (ia == (struct in_ifaddr *)0) 568 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 569 m->m_pkthdr.rcvif)); 570 /* 571 * The following happens if the packet was not addressed to us, 572 * and was received on an interface with no IP address: 573 * We find the first AF_INET address on the first non-loopback 574 * interface. 575 */ 576 if (ia == (struct in_ifaddr *)0) 577 for (ia = in_ifaddr.tqh_first; ia != NULL; 578 ia = ia->ia_list.tqe_next) { 579 if (ia->ia_ifp->if_flags & IFF_LOOPBACK) 580 continue; 581 break; 582 } 583 /* 584 * If we still didn't find an address, punt. We could have an 585 * interface up (and receiving packets) with no address. 586 */ 587 if (ia == (struct in_ifaddr *)0) { 588 m_freem(m); 589 goto done; 590 } 591 592 t = ia->ia_addr.sin_addr; 593 ip->ip_src = t; 594 ip->ip_ttl = MAXTTL; 595 596 if (optlen > 0) { 597 register u_char *cp; 598 int opt, cnt; 599 u_int len; 600 601 /* 602 * Retrieve any source routing from the incoming packet; 603 * add on any record-route or timestamp options. 604 */ 605 cp = (u_char *) (ip + 1); 606 if ((opts = ip_srcroute()) == 0 && 607 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 608 opts->m_len = sizeof(struct in_addr); 609 *mtod(opts, struct in_addr *) = zeroin_addr; 610 } 611 if (opts) { 612 #ifdef ICMPPRINTFS 613 if (icmpprintfs) 614 printf("icmp_reflect optlen %d rt %d => ", 615 optlen, opts->m_len); 616 #endif 617 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 618 opt = cp[IPOPT_OPTVAL]; 619 if (opt == IPOPT_EOL) 620 break; 621 if (opt == IPOPT_NOP) 622 len = 1; 623 else { 624 len = cp[IPOPT_OLEN]; 625 if (len <= 0 || len > cnt) 626 break; 627 } 628 /* 629 * Should check for overflow, but it "can't happen" 630 */ 631 if (opt == IPOPT_RR || opt == IPOPT_TS || 632 opt == IPOPT_SECURITY) { 633 bcopy((caddr_t)cp, 634 mtod(opts, caddr_t) + opts->m_len, len); 635 opts->m_len += len; 636 } 637 } 638 /* Terminate & pad, if necessary */ 639 if ((cnt = opts->m_len % 4) != 0) { 640 for (; cnt < 4; cnt++) { 641 *(mtod(opts, caddr_t) + opts->m_len) = 642 IPOPT_EOL; 643 opts->m_len++; 644 } 645 } 646 #ifdef ICMPPRINTFS 647 if (icmpprintfs) 648 printf("%d\n", opts->m_len); 649 #endif 650 } 651 /* 652 * Now strip out original options by copying rest of first 653 * mbuf's data back, and adjust the IP length. 654 */ 655 ip->ip_len -= optlen; 656 ip->ip_hl = sizeof(struct ip) >> 2; 657 m->m_len -= optlen; 658 if (m->m_flags & M_PKTHDR) 659 m->m_pkthdr.len -= optlen; 660 optlen += sizeof(struct ip); 661 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 662 (unsigned)(m->m_len - sizeof(struct ip))); 663 } 664 m->m_flags &= ~(M_BCAST|M_MCAST); 665 icmp_send(m, opts); 666 done: 667 if (opts) 668 (void)m_free(opts); 669 } 670 671 /* 672 * Send an icmp packet back to the ip level, 673 * after supplying a checksum. 674 */ 675 void 676 icmp_send(m, opts) 677 register struct mbuf *m; 678 struct mbuf *opts; 679 { 680 register struct ip *ip = mtod(m, struct ip *); 681 register int hlen; 682 register struct icmp *icp; 683 684 hlen = ip->ip_hl << 2; 685 m->m_data += hlen; 686 m->m_len -= hlen; 687 icp = mtod(m, struct icmp *); 688 icp->icmp_cksum = 0; 689 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 690 m->m_data -= hlen; 691 m->m_len += hlen; 692 #ifdef ICMPPRINTFS 693 if (icmpprintfs) 694 printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src); 695 #endif 696 #ifdef IPSEC 697 m->m_pkthdr.rcvif = NULL; 698 #endif /*IPSEC*/ 699 (void) ip_output(m, opts, NULL, 0, NULL); 700 } 701 702 n_time 703 iptime() 704 { 705 struct timeval atv; 706 u_long t; 707 708 microtime(&atv); 709 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 710 return (htonl(t)); 711 } 712 713 int 714 icmp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 715 int *name; 716 u_int namelen; 717 void *oldp; 718 size_t *oldlenp; 719 void *newp; 720 size_t newlen; 721 { 722 723 /* All sysctl names at this level are terminal. */ 724 if (namelen != 1) 725 return (ENOTDIR); 726 727 switch (name[0]) { 728 case ICMPCTL_MASKREPL: 729 return (sysctl_int(oldp, oldlenp, newp, newlen, &icmpmaskrepl)); 730 default: 731 return (ENOPROTOOPT); 732 } 733 /* NOTREACHED */ 734 } 735 736 static void 737 icmp_mtudisc(icp) 738 struct icmp *icp; 739 { 740 struct rtentry *rt; 741 struct sockaddr *dst = sintosa(&icmpsrc); 742 u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */ 743 int error; 744 745 /* Table of common MTUs: */ 746 747 static u_long mtu_table[] = {65535, 65280, 32000, 17914, 9180, 8166, 748 4352, 2002, 1492, 1006, 508, 296, 68, 0}; 749 750 rt = rtalloc1(dst, 1); 751 if (rt == 0) 752 return; 753 754 /* If we didn't get a host route, allocate one */ 755 756 if ((rt->rt_flags & RTF_HOST) == 0) { 757 struct rtentry *nrt; 758 759 error = rtrequest((int) RTM_ADD, dst, 760 (struct sockaddr *) rt->rt_gateway, 761 (struct sockaddr *) 0, 762 RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt); 763 if (error) { 764 rtfree(rt); 765 rtfree(nrt); 766 return; 767 } 768 nrt->rt_rmx = rt->rt_rmx; 769 rtfree(rt); 770 rt = nrt; 771 } 772 error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q); 773 if (error) { 774 rtfree(rt); 775 return; 776 } 777 778 if (mtu == 0) { 779 int i = 0; 780 781 mtu = icp->icmp_ip.ip_len; /* NTOHS happened in deliver: */ 782 /* Some 4.2BSD-based routers incorrectly adjust the ip_len */ 783 if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0) 784 mtu -= (icp->icmp_ip.ip_hl << 2); 785 786 /* If we still can't guess a value, try the route */ 787 788 if (mtu == 0) { 789 mtu = rt->rt_rmx.rmx_mtu; 790 791 /* If no route mtu, default to the interface mtu */ 792 793 if (mtu == 0) 794 mtu = rt->rt_ifp->if_mtu; 795 } 796 797 for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++) 798 if (mtu > mtu_table[i]) { 799 mtu = mtu_table[i]; 800 break; 801 } 802 } 803 804 /* 805 * XXX: RTV_MTU is overloaded, since the admin can set it 806 * to turn off PMTU for a route, and the kernel can 807 * set it to indicate a serious problem with PMTU 808 * on a route. We should be using a separate flag 809 * for the kernel to indicate this. 810 */ 811 812 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 813 if (mtu < 296 || mtu > rt->rt_ifp->if_mtu) 814 rt->rt_rmx.rmx_locks |= RTV_MTU; 815 else if (rt->rt_rmx.rmx_mtu > mtu || 816 rt->rt_rmx.rmx_mtu == 0) 817 rt->rt_rmx.rmx_mtu = mtu; 818 } 819 820 if (rt) 821 rtfree(rt); 822 } 823 824 /* 825 * Return the next larger or smaller MTU plateau (table from RFC 1191) 826 * given current value MTU. If DIR is less than zero, a larger plateau 827 * is returned; otherwise, a smaller value is returned. 828 */ 829 int 830 ip_next_mtu(mtu, dir) /* XXX */ 831 int mtu; 832 int dir; 833 { 834 static int mtutab[] = { 835 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296, 836 68, 0 837 }; 838 int i; 839 840 for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) { 841 if (mtu >= mtutab[i]) 842 break; 843 } 844 845 if (dir < 0) { 846 if (i == 0) { 847 return 0; 848 } else { 849 return mtutab[i - 1]; 850 } 851 } else { 852 if (mtutab[i] == 0) { 853 return 0; 854 } else if(mtu > mtutab[i]) { 855 return mtutab[i]; 856 } else { 857 return mtutab[i + 1]; 858 } 859 } 860 } 861 862 863 static void 864 icmp_mtudisc_timeout(rt, r) 865 struct rtentry *rt; 866 struct rttimer *r; 867 { 868 if (rt == NULL) 869 panic("icmp_mtudisc_timeout: bad route to timeout"); 870 if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == 871 (RTF_DYNAMIC | RTF_HOST)) { 872 rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt), 873 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 874 } else { 875 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 876 rt->rt_rmx.rmx_mtu = 0; 877 } 878 } 879 } 880
Indexes created Fri Oct 03 02:09:57 GMT 2025