ip_icmp.c revision 1.28
1 /* $NetBSD: ip_icmp.c,v 1.28 1998/02/15 18:24:26 tls 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 *)); 115 116 /* 117 * Generate an error packet of type error 118 * in response to bad packet ip. 119 */ 120 void 121 icmp_error(n, type, code, dest, destifp) 122 struct mbuf *n; 123 int type, code; 124 n_long dest; 125 struct ifnet *destifp; 126 { 127 register struct ip *oip = mtod(n, struct ip *), *nip; 128 register unsigned oiplen = oip->ip_hl << 2; 129 register struct icmp *icp; 130 register struct mbuf *m; 131 unsigned icmplen; 132 133 #ifdef ICMPPRINTFS 134 if (icmpprintfs) 135 printf("icmp_error(%x, %d, %d)\n", oip, type, code); 136 #endif 137 if (type != ICMP_REDIRECT) 138 icmpstat.icps_error++; 139 /* 140 * Don't send error if not the first fragment of message. 141 * Don't error if the old packet protocol was ICMP 142 * error message, only known informational types. 143 */ 144 if (oip->ip_off &~ (IP_MF|IP_DF)) 145 goto freeit; 146 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && 147 n->m_len >= oiplen + ICMP_MINLEN && 148 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { 149 icmpstat.icps_oldicmp++; 150 goto freeit; 151 } 152 /* Don't send error in response to a multicast or broadcast packet */ 153 if (n->m_flags & (M_BCAST|M_MCAST)) 154 goto freeit; 155 /* 156 * First, formulate icmp message 157 */ 158 m = m_gethdr(M_DONTWAIT, MT_HEADER); 159 if (m == NULL) 160 goto freeit; 161 icmplen = oiplen + min(8, oip->ip_len); 162 m->m_len = icmplen + ICMP_MINLEN; 163 MH_ALIGN(m, m->m_len); 164 icp = mtod(m, struct icmp *); 165 if ((u_int)type > ICMP_MAXTYPE) 166 panic("icmp_error"); 167 icmpstat.icps_outhist[type]++; 168 icp->icmp_type = type; 169 if (type == ICMP_REDIRECT) 170 icp->icmp_gwaddr.s_addr = dest; 171 else { 172 icp->icmp_void = 0; 173 /* 174 * The following assignments assume an overlay with the 175 * zeroed icmp_void field. 176 */ 177 if (type == ICMP_PARAMPROB) { 178 icp->icmp_pptr = code; 179 code = 0; 180 } else if (type == ICMP_UNREACH && 181 code == ICMP_UNREACH_NEEDFRAG && destifp) 182 icp->icmp_nextmtu = htons(destifp->if_mtu); 183 } 184 185 icp->icmp_code = code; 186 bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen); 187 nip = &icp->icmp_ip; 188 nip->ip_len = htons((u_int16_t)(nip->ip_len + oiplen)); 189 190 /* 191 * Now, copy old ip header (without options) 192 * in front of icmp message. 193 */ 194 if (m->m_data - sizeof(struct ip) < m->m_pktdat) 195 panic("icmp len"); 196 m->m_data -= sizeof(struct ip); 197 m->m_len += sizeof(struct ip); 198 m->m_pkthdr.len = m->m_len; 199 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; 200 nip = mtod(m, struct ip *); 201 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); 202 nip->ip_len = m->m_len; 203 nip->ip_hl = sizeof(struct ip) >> 2; 204 nip->ip_p = IPPROTO_ICMP; 205 nip->ip_tos = 0; 206 icmp_reflect(m); 207 208 freeit: 209 m_freem(n); 210 } 211 212 static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; 213 static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; 214 static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; 215 struct sockaddr_in icmpmask = { 8, 0 }; 216 217 /* 218 * Process a received ICMP message. 219 */ 220 void 221 #if __STDC__ 222 icmp_input(struct mbuf *m, ...) 223 #else 224 icmp_input(m, va_alist) 225 struct mbuf *m; 226 va_dcl 227 #endif 228 { 229 register struct icmp *icp; 230 register struct ip *ip = mtod(m, struct ip *); 231 int icmplen = ip->ip_len; 232 register int i; 233 struct in_ifaddr *ia; 234 void *(*ctlfunc) __P((int, struct sockaddr *, void *)); 235 int code; 236 extern u_char ip_protox[]; 237 int hlen; 238 va_list ap; 239 240 va_start(ap, m); 241 hlen = va_arg(ap, int); 242 va_end(ap); 243 244 /* 245 * Locate icmp structure in mbuf, and check 246 * that not corrupted and of at least minimum length. 247 */ 248 #ifdef ICMPPRINTFS 249 if (icmpprintfs) 250 printf("icmp_input from %x to %x, len %d\n", 251 ntohl(ip->ip_src.s_addr), ntohl(ip->ip_dst.s_addr), 252 icmplen); 253 #endif 254 if (icmplen < ICMP_MINLEN) { 255 icmpstat.icps_tooshort++; 256 goto freeit; 257 } 258 i = hlen + min(icmplen, ICMP_ADVLENMIN); 259 if (m->m_len < i && (m = m_pullup(m, i)) == 0) { 260 icmpstat.icps_tooshort++; 261 return; 262 } 263 ip = mtod(m, struct ip *); 264 m->m_len -= hlen; 265 m->m_data += hlen; 266 icp = mtod(m, struct icmp *); 267 if (in_cksum(m, icmplen)) { 268 icmpstat.icps_checksum++; 269 goto freeit; 270 } 271 m->m_len += hlen; 272 m->m_data -= hlen; 273 274 #ifdef ICMPPRINTFS 275 /* 276 * Message type specific processing. 277 */ 278 if (icmpprintfs) 279 printf("icmp_input, type %d code %d\n", icp->icmp_type, 280 icp->icmp_code); 281 #endif 282 if (icp->icmp_type > ICMP_MAXTYPE) 283 goto raw; 284 icmpstat.icps_inhist[icp->icmp_type]++; 285 code = icp->icmp_code; 286 switch (icp->icmp_type) { 287 288 case ICMP_UNREACH: 289 switch (code) { 290 case ICMP_UNREACH_NET: 291 case ICMP_UNREACH_HOST: 292 case ICMP_UNREACH_PROTOCOL: 293 case ICMP_UNREACH_PORT: 294 case ICMP_UNREACH_SRCFAIL: 295 code += PRC_UNREACH_NET; 296 break; 297 298 case ICMP_UNREACH_NEEDFRAG: 299 code = PRC_MSGSIZE; 300 break; 301 302 case ICMP_UNREACH_NET_UNKNOWN: 303 case ICMP_UNREACH_NET_PROHIB: 304 case ICMP_UNREACH_TOSNET: 305 code = PRC_UNREACH_NET; 306 break; 307 308 case ICMP_UNREACH_HOST_UNKNOWN: 309 case ICMP_UNREACH_ISOLATED: 310 case ICMP_UNREACH_HOST_PROHIB: 311 case ICMP_UNREACH_TOSHOST: 312 code = PRC_UNREACH_HOST; 313 break; 314 315 default: 316 goto badcode; 317 } 318 goto deliver; 319 320 case ICMP_TIMXCEED: 321 if (code > 1) 322 goto badcode; 323 code += PRC_TIMXCEED_INTRANS; 324 goto deliver; 325 326 case ICMP_PARAMPROB: 327 if (code > 1) 328 goto badcode; 329 code = PRC_PARAMPROB; 330 goto deliver; 331 332 case ICMP_SOURCEQUENCH: 333 if (code) 334 goto badcode; 335 code = PRC_QUENCH; 336 goto deliver; 337 338 deliver: 339 /* 340 * Problem with datagram; advise higher level routines. 341 */ 342 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 343 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 344 icmpstat.icps_badlen++; 345 goto freeit; 346 } 347 if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr)) 348 goto badcode; 349 NTOHS(icp->icmp_ip.ip_len); 350 #ifdef ICMPPRINTFS 351 if (icmpprintfs) 352 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); 353 #endif 354 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 355 if (code == PRC_MSGSIZE && ip_mtudisc) 356 icmp_mtudisc(icp); 357 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; 358 if (ctlfunc) 359 (*ctlfunc)(code, sintosa(&icmpsrc), &icp->icmp_ip); 360 break; 361 362 badcode: 363 icmpstat.icps_badcode++; 364 break; 365 366 case ICMP_ECHO: 367 icp->icmp_type = ICMP_ECHOREPLY; 368 goto reflect; 369 370 case ICMP_TSTAMP: 371 if (icmplen < ICMP_TSLEN) { 372 icmpstat.icps_badlen++; 373 break; 374 } 375 icp->icmp_type = ICMP_TSTAMPREPLY; 376 icp->icmp_rtime = iptime(); 377 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ 378 goto reflect; 379 380 case ICMP_MASKREQ: 381 if (icmpmaskrepl == 0) 382 break; 383 /* 384 * We are not able to respond with all ones broadcast 385 * unless we receive it over a point-to-point interface. 386 */ 387 if (icmplen < ICMP_MASKLEN) { 388 icmpstat.icps_badlen++; 389 break; 390 } 391 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 392 in_nullhost(ip->ip_dst)) 393 icmpdst.sin_addr = ip->ip_src; 394 else 395 icmpdst.sin_addr = ip->ip_dst; 396 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 397 m->m_pkthdr.rcvif)); 398 if (ia == 0) 399 break; 400 icp->icmp_type = ICMP_MASKREPLY; 401 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; 402 if (in_nullhost(ip->ip_src)) { 403 if (ia->ia_ifp->if_flags & IFF_BROADCAST) 404 ip->ip_src = ia->ia_broadaddr.sin_addr; 405 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) 406 ip->ip_src = ia->ia_dstaddr.sin_addr; 407 } 408 reflect: 409 ip->ip_len += hlen; /* since ip_input deducts this */ 410 icmpstat.icps_reflect++; 411 icmpstat.icps_outhist[icp->icmp_type]++; 412 icmp_reflect(m); 413 return; 414 415 case ICMP_REDIRECT: 416 if (code > 3) 417 goto badcode; 418 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || 419 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { 420 icmpstat.icps_badlen++; 421 break; 422 } 423 /* 424 * Short circuit routing redirects to force 425 * immediate change in the kernel's routing 426 * tables. The message is also handed to anyone 427 * listening on a raw socket (e.g. the routing 428 * daemon for use in updating its tables). 429 */ 430 icmpgw.sin_addr = ip->ip_src; 431 icmpdst.sin_addr = icp->icmp_gwaddr; 432 #ifdef ICMPPRINTFS 433 if (icmpprintfs) 434 printf("redirect dst %x to %x\n", icp->icmp_ip.ip_dst, 435 icp->icmp_gwaddr); 436 #endif 437 icmpsrc.sin_addr = icp->icmp_ip.ip_dst; 438 rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst), 439 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, 440 sintosa(&icmpgw), (struct rtentry **)0); 441 pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc)); 442 break; 443 444 /* 445 * No kernel processing for the following; 446 * just fall through to send to raw listener. 447 */ 448 case ICMP_ECHOREPLY: 449 case ICMP_ROUTERADVERT: 450 case ICMP_ROUTERSOLICIT: 451 case ICMP_TSTAMPREPLY: 452 case ICMP_IREQREPLY: 453 case ICMP_MASKREPLY: 454 default: 455 break; 456 } 457 458 raw: 459 rip_input(m); 460 return; 461 462 freeit: 463 m_freem(m); 464 } 465 466 /* 467 * Reflect the ip packet back to the source 468 */ 469 void 470 icmp_reflect(m) 471 struct mbuf *m; 472 { 473 register struct ip *ip = mtod(m, struct ip *); 474 register struct in_ifaddr *ia; 475 register struct ifaddr *ifa; 476 struct in_addr t; 477 struct mbuf *opts = 0; 478 int optlen = (ip->ip_hl << 2) - sizeof(struct ip); 479 480 if (!in_canforward(ip->ip_src) && 481 ((ip->ip_src.s_addr & IN_CLASSA_NET) != 482 htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { 483 m_freem(m); /* Bad return address */ 484 goto done; /* ip_output() will check for broadcast */ 485 } 486 t = ip->ip_dst; 487 ip->ip_dst = ip->ip_src; 488 /* 489 * If the incoming packet was addressed directly to us, 490 * use dst as the src for the reply. Otherwise (broadcast 491 * or anonymous), use the address which corresponds 492 * to the incoming interface. 493 */ 494 INADDR_TO_IA(t, ia); 495 if (ia == NULL && (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 496 for (ifa = m->m_pkthdr.rcvif->if_addrlist.tqh_first; 497 ifa != NULL; ifa = ifa->ifa_list.tqe_next) { 498 if (ifa->ifa_addr->sa_family != AF_INET) 499 continue; 500 ia = ifatoia(ifa); 501 if (in_hosteq(t, ia->ia_broadaddr.sin_addr)) 502 break; 503 } 504 } 505 506 icmpdst.sin_addr = t; 507 if (ia == (struct in_ifaddr *)0) 508 ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst), 509 m->m_pkthdr.rcvif)); 510 /* 511 * The following happens if the packet was not addressed to us, 512 * and was received on an interface with no IP address: 513 * We find the first AF_INET address on the first non-loopback 514 * interface. 515 */ 516 if (ia == (struct in_ifaddr *)0) 517 for (ia = in_ifaddr.tqh_first; ia != NULL; 518 ia = ia->ia_list.tqe_next) { 519 if (ia->ia_ifp->if_flags & IFF_LOOPBACK) 520 continue; 521 break; 522 } 523 t = ia->ia_addr.sin_addr; 524 ip->ip_src = t; 525 ip->ip_ttl = MAXTTL; 526 527 if (optlen > 0) { 528 register u_char *cp; 529 int opt, cnt; 530 u_int len; 531 532 /* 533 * Retrieve any source routing from the incoming packet; 534 * add on any record-route or timestamp options. 535 */ 536 cp = (u_char *) (ip + 1); 537 if ((opts = ip_srcroute()) == 0 && 538 (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { 539 opts->m_len = sizeof(struct in_addr); 540 *mtod(opts, struct in_addr *) = zeroin_addr; 541 } 542 if (opts) { 543 #ifdef ICMPPRINTFS 544 if (icmpprintfs) 545 printf("icmp_reflect optlen %d rt %d => ", 546 optlen, opts->m_len); 547 #endif 548 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { 549 opt = cp[IPOPT_OPTVAL]; 550 if (opt == IPOPT_EOL) 551 break; 552 if (opt == IPOPT_NOP) 553 len = 1; 554 else { 555 len = cp[IPOPT_OLEN]; 556 if (len <= 0 || len > cnt) 557 break; 558 } 559 /* 560 * Should check for overflow, but it "can't happen" 561 */ 562 if (opt == IPOPT_RR || opt == IPOPT_TS || 563 opt == IPOPT_SECURITY) { 564 bcopy((caddr_t)cp, 565 mtod(opts, caddr_t) + opts->m_len, len); 566 opts->m_len += len; 567 } 568 } 569 /* Terminate & pad, if necessary */ 570 if ((cnt = opts->m_len % 4) != 0) { 571 for (; cnt < 4; cnt++) { 572 *(mtod(opts, caddr_t) + opts->m_len) = 573 IPOPT_EOL; 574 opts->m_len++; 575 } 576 } 577 #ifdef ICMPPRINTFS 578 if (icmpprintfs) 579 printf("%d\n", opts->m_len); 580 #endif 581 } 582 /* 583 * Now strip out original options by copying rest of first 584 * mbuf's data back, and adjust the IP length. 585 */ 586 ip->ip_len -= optlen; 587 ip->ip_hl = sizeof(struct ip) >> 2; 588 m->m_len -= optlen; 589 if (m->m_flags & M_PKTHDR) 590 m->m_pkthdr.len -= optlen; 591 optlen += sizeof(struct ip); 592 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), 593 (unsigned)(m->m_len - sizeof(struct ip))); 594 } 595 m->m_flags &= ~(M_BCAST|M_MCAST); 596 icmp_send(m, opts); 597 done: 598 if (opts) 599 (void)m_free(opts); 600 } 601 602 /* 603 * Send an icmp packet back to the ip level, 604 * after supplying a checksum. 605 */ 606 void 607 icmp_send(m, opts) 608 register struct mbuf *m; 609 struct mbuf *opts; 610 { 611 register struct ip *ip = mtod(m, struct ip *); 612 register int hlen; 613 register struct icmp *icp; 614 615 hlen = ip->ip_hl << 2; 616 m->m_data += hlen; 617 m->m_len -= hlen; 618 icp = mtod(m, struct icmp *); 619 icp->icmp_cksum = 0; 620 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); 621 m->m_data -= hlen; 622 m->m_len += hlen; 623 #ifdef ICMPPRINTFS 624 if (icmpprintfs) 625 printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src); 626 #endif 627 (void) ip_output(m, opts, NULL, 0, NULL); 628 } 629 630 n_time 631 iptime() 632 { 633 struct timeval atv; 634 u_long t; 635 636 microtime(&atv); 637 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; 638 return (htonl(t)); 639 } 640 641 int 642 icmp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 643 int *name; 644 u_int namelen; 645 void *oldp; 646 size_t *oldlenp; 647 void *newp; 648 size_t newlen; 649 { 650 651 /* All sysctl names at this level are terminal. */ 652 if (namelen != 1) 653 return (ENOTDIR); 654 655 switch (name[0]) { 656 case ICMPCTL_MASKREPL: 657 return (sysctl_int(oldp, oldlenp, newp, newlen, &icmpmaskrepl)); 658 default: 659 return (ENOPROTOOPT); 660 } 661 /* NOTREACHED */ 662 } 663 664 static void 665 icmp_mtudisc(icp) 666 struct icmp *icp; 667 { 668 struct rtentry *rt; 669 struct sockaddr *dst = sintosa(&icmpsrc); 670 u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */ 671 672 /* Table of common MTUs: */ 673 674 static u_long mtu_table[] = {65535, 65280, 32000, 17914, 9180, 8166, 675 4352, 2002, 1492, 1006, 508, 296, 68, 0}; 676 677 rt = rtalloc1(dst, 1); 678 if (rt == 0) 679 return; 680 681 /* If we didn't get a host route, allocate one */ 682 683 if ((rt->rt_flags & RTF_HOST) == 0) { 684 struct rtentry *nrt; 685 int error; 686 687 error = rtrequest((int) RTM_ADD, dst, 688 (struct sockaddr *) rt->rt_gateway, 689 (struct sockaddr *) 0, 690 RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt); 691 if (error) { 692 rtfree(rt); 693 rtfree(nrt); 694 return; 695 } 696 nrt->rt_rmx = rt->rt_rmx; 697 rtfree(rt); 698 rt = nrt; 699 } 700 701 if (mtu == 0) { 702 int i = 0; 703 704 mtu = icp->icmp_ip.ip_len; /* NTOHS happened in deliver: */ 705 /* Some 4.2BSD-based routers incorrectly adjust the ip_len */ 706 if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0) 707 mtu -= (icp->icmp_ip.ip_hl << 2); 708 709 /* If we still can't guess a value, try the route */ 710 711 if (mtu == 0) { 712 mtu = rt->rt_rmx.rmx_mtu; 713 714 /* If no route mtu, default to the interface mtu */ 715 716 if (mtu == 0) 717 mtu = rt->rt_ifp->if_mtu; 718 } 719 720 for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++) 721 if (mtu > mtu_table[i]) { 722 mtu = mtu_table[i]; 723 break; 724 } 725 } 726 727 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { 728 if (mtu < 296 || mtu > rt->rt_ifp->if_mtu) 729 rt->rt_rmx.rmx_locks |= RTV_MTU; 730 else if (rt->rt_rmx.rmx_mtu > mtu || 731 rt->rt_rmx.rmx_mtu == 0) 732 rt->rt_rmx.rmx_mtu = mtu; 733 } 734 735 if (rt) 736 rtfree(rt); 737 } 738
Indexes created Fri Sep 26 20:09:58 GMT 2025