ip_input.c revision 1.109
1 /* $NetBSD: ip_input.c,v 1.109 2000/03/30 13:24:59 augustss Exp $ */ 2 3 /* 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * 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. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /*- 33 * Copyright (c) 1998 The NetBSD Foundation, Inc. 34 * All rights reserved. 35 * 36 * This code is derived from software contributed to The NetBSD Foundation 37 * by Public Access Networks Corporation ("Panix"). It was developed under 38 * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon. 39 * 40 * Redistribution and use in source and binary forms, with or without 41 * modification, are permitted provided that the following conditions 42 * are met: 43 * 1. Redistributions of source code must retain the above copyright 44 * notice, this list of conditions and the following disclaimer. 45 * 2. Redistributions in binary form must reproduce the above copyright 46 * notice, this list of conditions and the following disclaimer in the 47 * documentation and/or other materials provided with the distribution. 48 * 3. All advertising materials mentioning features or use of this software 49 * must display the following acknowledgement: 50 * This product includes software developed by the NetBSD 51 * Foundation, Inc. and its contributors. 52 * 4. Neither the name of The NetBSD Foundation nor the names of its 53 * contributors may be used to endorse or promote products derived 54 * from this software without specific prior written permission. 55 * 56 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 57 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 58 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 59 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 60 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 61 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 62 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 63 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 64 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 65 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 66 * POSSIBILITY OF 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_input.c 8.2 (Berkeley) 1/4/94 102 */ 103 104 #include "opt_gateway.h" 105 #include "opt_pfil_hooks.h" 106 #include "opt_ipsec.h" 107 #include "opt_mrouting.h" 108 109 #include <sys/param.h> 110 #include <sys/systm.h> 111 #include <sys/malloc.h> 112 #include <sys/mbuf.h> 113 #include <sys/domain.h> 114 #include <sys/protosw.h> 115 #include <sys/socket.h> 116 #include <sys/socketvar.h> 117 #include <sys/errno.h> 118 #include <sys/time.h> 119 #include <sys/kernel.h> 120 #include <sys/proc.h> 121 #include <sys/pool.h> 122 123 #include <vm/vm.h> 124 #include <sys/sysctl.h> 125 126 #include <net/if.h> 127 #include <net/if_dl.h> 128 #include <net/route.h> 129 #include <net/pfil.h> 130 131 #include <netinet/in.h> 132 #include <netinet/in_systm.h> 133 #include <netinet/ip.h> 134 #include <netinet/in_pcb.h> 135 #include <netinet/in_var.h> 136 #include <netinet/ip_var.h> 137 #include <netinet/ip_icmp.h> 138 /* just for gif_ttl */ 139 #include <netinet/in_gif.h> 140 #include "gif.h" 141 142 #ifdef IPSEC 143 #include <netinet6/ipsec.h> 144 #include <netkey/key.h> 145 #include <netkey/key_debug.h> 146 #endif 147 148 #ifndef IPFORWARDING 149 #ifdef GATEWAY 150 #define IPFORWARDING 1 /* forward IP packets not for us */ 151 #else /* GATEWAY */ 152 #define IPFORWARDING 0 /* don't forward IP packets not for us */ 153 #endif /* GATEWAY */ 154 #endif /* IPFORWARDING */ 155 #ifndef IPSENDREDIRECTS 156 #define IPSENDREDIRECTS 1 157 #endif 158 #ifndef IPFORWSRCRT 159 #define IPFORWSRCRT 1 /* forward source-routed packets */ 160 #endif 161 #ifndef IPALLOWSRCRT 162 #define IPALLOWSRCRT 1 /* allow source-routed packets */ 163 #endif 164 #ifndef IPMTUDISC 165 #define IPMTUDISC 0 166 #endif 167 #ifndef IPMTUDISCTIMEOUT 168 #define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */ 169 #endif 170 171 /* 172 * Note: DIRECTED_BROADCAST is handled this way so that previous 173 * configuration using this option will Just Work. 174 */ 175 #ifndef IPDIRECTEDBCAST 176 #ifdef DIRECTED_BROADCAST 177 #define IPDIRECTEDBCAST 1 178 #else 179 #define IPDIRECTEDBCAST 0 180 #endif /* DIRECTED_BROADCAST */ 181 #endif /* IPDIRECTEDBCAST */ 182 int ipforwarding = IPFORWARDING; 183 int ipsendredirects = IPSENDREDIRECTS; 184 int ip_defttl = IPDEFTTL; 185 int ip_forwsrcrt = IPFORWSRCRT; 186 int ip_directedbcast = IPDIRECTEDBCAST; 187 int ip_allowsrcrt = IPALLOWSRCRT; 188 int ip_mtudisc = IPMTUDISC; 189 u_int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 190 #ifdef DIAGNOSTIC 191 int ipprintfs = 0; 192 #endif 193 194 struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 195 196 extern struct domain inetdomain; 197 int ipqmaxlen = IFQ_MAXLEN; 198 struct in_ifaddrhead in_ifaddr; 199 struct in_ifaddrhashhead *in_ifaddrhashtbl; 200 struct ifqueue ipintrq; 201 struct ipstat ipstat; 202 u_int16_t ip_id; 203 204 struct ipqhead ipq; 205 int ipq_locked; 206 207 static __inline int ipq_lock_try __P((void)); 208 static __inline void ipq_unlock __P((void)); 209 210 static __inline int 211 ipq_lock_try() 212 { 213 int s; 214 215 s = splimp(); 216 if (ipq_locked) { 217 splx(s); 218 return (0); 219 } 220 ipq_locked = 1; 221 splx(s); 222 return (1); 223 } 224 225 static __inline void 226 ipq_unlock() 227 { 228 int s; 229 230 s = splimp(); 231 ipq_locked = 0; 232 splx(s); 233 } 234 235 #ifdef DIAGNOSTIC 236 #define IPQ_LOCK() \ 237 do { \ 238 if (ipq_lock_try() == 0) { \ 239 printf("%s:%d: ipq already locked\n", __FILE__, __LINE__); \ 240 panic("ipq_lock"); \ 241 } \ 242 } while (0) 243 #define IPQ_LOCK_CHECK() \ 244 do { \ 245 if (ipq_locked == 0) { \ 246 printf("%s:%d: ipq lock not held\n", __FILE__, __LINE__); \ 247 panic("ipq lock check"); \ 248 } \ 249 } while (0) 250 #else 251 #define IPQ_LOCK() (void) ipq_lock_try() 252 #define IPQ_LOCK_CHECK() /* nothing */ 253 #endif 254 255 #define IPQ_UNLOCK() ipq_unlock() 256 257 struct pool ipqent_pool; 258 259 /* 260 * We need to save the IP options in case a protocol wants to respond 261 * to an incoming packet over the same route if the packet got here 262 * using IP source routing. This allows connection establishment and 263 * maintenance when the remote end is on a network that is not known 264 * to us. 265 */ 266 int ip_nhops = 0; 267 static struct ip_srcrt { 268 struct in_addr dst; /* final destination */ 269 char nop; /* one NOP to align */ 270 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 271 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 272 } ip_srcrt; 273 274 static void save_rte __P((u_char *, struct in_addr)); 275 276 /* 277 * IP initialization: fill in IP protocol switch table. 278 * All protocols not implemented in kernel go to raw IP protocol handler. 279 */ 280 void 281 ip_init() 282 { 283 struct protosw *pr; 284 int i; 285 286 pool_init(&ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl", 287 0, NULL, NULL, M_IPQ); 288 289 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 290 if (pr == 0) 291 panic("ip_init"); 292 for (i = 0; i < IPPROTO_MAX; i++) 293 ip_protox[i] = pr - inetsw; 294 for (pr = inetdomain.dom_protosw; 295 pr < inetdomain.dom_protoswNPROTOSW; pr++) 296 if (pr->pr_domain->dom_family == PF_INET && 297 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 298 ip_protox[pr->pr_protocol] = pr - inetsw; 299 LIST_INIT(&ipq); 300 ip_id = time.tv_sec & 0xffff; 301 ipintrq.ifq_maxlen = ipqmaxlen; 302 TAILQ_INIT(&in_ifaddr); 303 in_ifaddrhashtbl = 304 hashinit(IN_IFADDR_HASH_SIZE, M_IFADDR, M_WAITOK, &in_ifaddrhash); 305 if (ip_mtudisc != 0) 306 ip_mtudisc_timeout_q = 307 rt_timer_queue_create(ip_mtudisc_timeout); 308 #ifdef GATEWAY 309 ipflow_init(); 310 #endif 311 } 312 313 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 314 struct route ipforward_rt; 315 316 /* 317 * IP software interrupt routine 318 */ 319 void 320 ipintr() 321 { 322 int s; 323 struct mbuf *m; 324 325 while (1) { 326 s = splimp(); 327 IF_DEQUEUE(&ipintrq, m); 328 splx(s); 329 if (m == 0) 330 return; 331 ip_input(m); 332 } 333 } 334 335 /* 336 * Ip input routine. Checksum and byte swap header. If fragmented 337 * try to reassemble. Process options. Pass to next level. 338 */ 339 void 340 ip_input(struct mbuf *m) 341 { 342 struct ip *ip = NULL; 343 struct ipq *fp; 344 struct in_ifaddr *ia; 345 struct ifaddr *ifa; 346 struct ipqent *ipqe; 347 int hlen = 0, mff, len; 348 int downmatch; 349 #ifdef PFIL_HOOKS 350 struct packet_filter_hook *pfh; 351 struct mbuf *m0; 352 int rv; 353 #endif /* PFIL_HOOKS */ 354 355 #ifdef DIAGNOSTIC 356 if ((m->m_flags & M_PKTHDR) == 0) 357 panic("ipintr no HDR"); 358 #endif 359 #ifdef IPSEC 360 /* 361 * should the inner packet be considered authentic? 362 * see comment in ah4_input(). 363 */ 364 if (m) { 365 m->m_flags &= ~M_AUTHIPHDR; 366 m->m_flags &= ~M_AUTHIPDGM; 367 } 368 #endif 369 /* 370 * If no IP addresses have been set yet but the interfaces 371 * are receiving, can't do anything with incoming packets yet. 372 */ 373 if (in_ifaddr.tqh_first == 0) 374 goto bad; 375 ipstat.ips_total++; 376 if (m->m_len < sizeof (struct ip) && 377 (m = m_pullup(m, sizeof (struct ip))) == 0) { 378 ipstat.ips_toosmall++; 379 return; 380 } 381 ip = mtod(m, struct ip *); 382 if (ip->ip_v != IPVERSION) { 383 ipstat.ips_badvers++; 384 goto bad; 385 } 386 hlen = ip->ip_hl << 2; 387 if (hlen < sizeof(struct ip)) { /* minimum header length */ 388 ipstat.ips_badhlen++; 389 goto bad; 390 } 391 if (hlen > m->m_len) { 392 if ((m = m_pullup(m, hlen)) == 0) { 393 ipstat.ips_badhlen++; 394 return; 395 } 396 ip = mtod(m, struct ip *); 397 } 398 399 /* 400 * RFC1122: packets with a multicast source address are 401 * not allowed. 402 */ 403 if (IN_MULTICAST(ip->ip_src.s_addr)) { 404 /* XXX stat */ 405 goto bad; 406 } 407 408 if (in_cksum(m, hlen) != 0) { 409 ipstat.ips_badsum++; 410 goto bad; 411 } 412 413 /* 414 * Convert fields to host representation. 415 */ 416 NTOHS(ip->ip_len); 417 NTOHS(ip->ip_off); 418 len = ip->ip_len; 419 420 /* 421 * Check for additional length bogosity 422 */ 423 if (len < hlen) { 424 ipstat.ips_badlen++; 425 goto bad; 426 } 427 428 /* 429 * Check that the amount of data in the buffers 430 * is as at least much as the IP header would have us expect. 431 * Trim mbufs if longer than we expect. 432 * Drop packet if shorter than we expect. 433 */ 434 if (m->m_pkthdr.len < len) { 435 ipstat.ips_tooshort++; 436 goto bad; 437 } 438 if (m->m_pkthdr.len > len) { 439 if (m->m_len == m->m_pkthdr.len) { 440 m->m_len = len; 441 m->m_pkthdr.len = len; 442 } else 443 m_adj(m, len - m->m_pkthdr.len); 444 } 445 446 #ifdef IPSEC 447 /* ipflow (IP fast fowarding) is not compatible with IPsec. */ 448 m->m_flags &= ~M_CANFASTFWD; 449 #else 450 /* 451 * Assume that we can create a fast-forward IP flow entry 452 * based on this packet. 453 */ 454 m->m_flags |= M_CANFASTFWD; 455 #endif 456 457 #ifdef PFIL_HOOKS 458 /* 459 * Run through list of hooks for input packets. If there are any 460 * filters which require that additional packets in the flow are 461 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 462 * Note that filters must _never_ set this flag, as another filter 463 * in the list may have previously cleared it. 464 */ 465 m0 = m; 466 pfh = pfil_hook_get(PFIL_IN, &inetsw[ip_protox[IPPROTO_IP]].pr_pfh); 467 for (; pfh; pfh = pfh->pfil_link.tqe_next) 468 if (pfh->pfil_func) { 469 rv = pfh->pfil_func(ip, hlen, 470 m->m_pkthdr.rcvif, 0, &m0); 471 if (rv) 472 return; 473 m = m0; 474 if (m == NULL) 475 return; 476 ip = mtod(m, struct ip *); 477 } 478 #endif /* PFIL_HOOKS */ 479 480 /* 481 * Process options and, if not destined for us, 482 * ship it on. ip_dooptions returns 1 when an 483 * error was detected (causing an icmp message 484 * to be sent and the original packet to be freed). 485 */ 486 ip_nhops = 0; /* for source routed packets */ 487 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 488 return; 489 490 /* 491 * Check our list of addresses, to see if the packet is for us. 492 * 493 * Traditional 4.4BSD did not consult IFF_UP at all. 494 * The behavior here is to treat addresses on !IFF_UP interface 495 * as not mine. 496 */ 497 downmatch = 0; 498 for (ia = IN_IFADDR_HASH(ip->ip_dst.s_addr).lh_first; 499 ia != NULL; 500 ia = ia->ia_hash.le_next) { 501 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) { 502 if ((ia->ia_ifp->if_flags & IFF_UP) != 0) 503 break; 504 else 505 downmatch++; 506 } 507 } 508 if (ia != NULL) 509 goto ours; 510 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 511 for (ifa = m->m_pkthdr.rcvif->if_addrlist.tqh_first; 512 ifa != NULL; ifa = ifa->ifa_list.tqe_next) { 513 if (ifa->ifa_addr->sa_family != AF_INET) continue; 514 ia = ifatoia(ifa); 515 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 516 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 517 /* 518 * Look for all-0's host part (old broadcast addr), 519 * either for subnet or net. 520 */ 521 ip->ip_dst.s_addr == ia->ia_subnet || 522 ip->ip_dst.s_addr == ia->ia_net) 523 goto ours; 524 /* 525 * An interface with IP address zero accepts 526 * all packets that arrive on that interface. 527 */ 528 if (in_nullhost(ia->ia_addr.sin_addr)) 529 goto ours; 530 } 531 } 532 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 533 struct in_multi *inm; 534 #ifdef MROUTING 535 extern struct socket *ip_mrouter; 536 537 if (m->m_flags & M_EXT) { 538 if ((m = m_pullup(m, hlen)) == 0) { 539 ipstat.ips_toosmall++; 540 return; 541 } 542 ip = mtod(m, struct ip *); 543 } 544 545 if (ip_mrouter) { 546 /* 547 * If we are acting as a multicast router, all 548 * incoming multicast packets are passed to the 549 * kernel-level multicast forwarding function. 550 * The packet is returned (relatively) intact; if 551 * ip_mforward() returns a non-zero value, the packet 552 * must be discarded, else it may be accepted below. 553 * 554 * (The IP ident field is put in the same byte order 555 * as expected when ip_mforward() is called from 556 * ip_output().) 557 */ 558 if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) { 559 ipstat.ips_cantforward++; 560 m_freem(m); 561 return; 562 } 563 564 /* 565 * The process-level routing demon needs to receive 566 * all multicast IGMP packets, whether or not this 567 * host belongs to their destination groups. 568 */ 569 if (ip->ip_p == IPPROTO_IGMP) 570 goto ours; 571 ipstat.ips_forward++; 572 } 573 #endif 574 /* 575 * See if we belong to the destination multicast group on the 576 * arrival interface. 577 */ 578 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 579 if (inm == NULL) { 580 ipstat.ips_cantforward++; 581 m_freem(m); 582 return; 583 } 584 goto ours; 585 } 586 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 587 in_nullhost(ip->ip_dst)) 588 goto ours; 589 590 /* 591 * Not for us; forward if possible and desirable. 592 */ 593 if (ipforwarding == 0) { 594 ipstat.ips_cantforward++; 595 m_freem(m); 596 } else { 597 /* 598 * If ip_dst matched any of my address on !IFF_UP interface, 599 * and there's no IFF_UP interface that matches ip_dst, 600 * send icmp unreach. Forwarding it will result in in-kernel 601 * forwarding loop till TTL goes to 0. 602 */ 603 if (downmatch) { 604 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 605 ipstat.ips_cantforward++; 606 return; 607 } 608 ip_forward(m, 0); 609 } 610 return; 611 612 ours: 613 /* 614 * If offset or IP_MF are set, must reassemble. 615 * Otherwise, nothing need be done. 616 * (We could look in the reassembly queue to see 617 * if the packet was previously fragmented, 618 * but it's not worth the time; just let them time out.) 619 */ 620 if (ip->ip_off & ~(IP_DF|IP_RF)) { 621 /* 622 * Look for queue of fragments 623 * of this datagram. 624 */ 625 IPQ_LOCK(); 626 for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next) 627 if (ip->ip_id == fp->ipq_id && 628 in_hosteq(ip->ip_src, fp->ipq_src) && 629 in_hosteq(ip->ip_dst, fp->ipq_dst) && 630 ip->ip_p == fp->ipq_p) 631 goto found; 632 fp = 0; 633 found: 634 635 /* 636 * Adjust ip_len to not reflect header, 637 * set ipqe_mff if more fragments are expected, 638 * convert offset of this to bytes. 639 */ 640 ip->ip_len -= hlen; 641 mff = (ip->ip_off & IP_MF) != 0; 642 if (mff) { 643 /* 644 * Make sure that fragments have a data length 645 * that's a non-zero multiple of 8 bytes. 646 */ 647 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 648 ipstat.ips_badfrags++; 649 IPQ_UNLOCK(); 650 goto bad; 651 } 652 } 653 ip->ip_off <<= 3; 654 655 /* 656 * If datagram marked as having more fragments 657 * or if this is not the first fragment, 658 * attempt reassembly; if it succeeds, proceed. 659 */ 660 if (mff || ip->ip_off) { 661 ipstat.ips_fragments++; 662 ipqe = pool_get(&ipqent_pool, PR_NOWAIT); 663 if (ipqe == NULL) { 664 ipstat.ips_rcvmemdrop++; 665 IPQ_UNLOCK(); 666 goto bad; 667 } 668 ipqe->ipqe_mff = mff; 669 ipqe->ipqe_m = m; 670 ipqe->ipqe_ip = ip; 671 m = ip_reass(ipqe, fp); 672 if (m == 0) { 673 IPQ_UNLOCK(); 674 return; 675 } 676 ipstat.ips_reassembled++; 677 ip = mtod(m, struct ip *); 678 hlen = ip->ip_hl << 2; 679 ip->ip_len += hlen; 680 } else 681 if (fp) 682 ip_freef(fp); 683 IPQ_UNLOCK(); 684 } 685 686 /* 687 * Switch out to protocol's input routine. 688 */ 689 #if IFA_STATS 690 ia->ia_ifa.ifa_data.ifad_inbytes += ip->ip_len; 691 #endif 692 ipstat.ips_delivered++; 693 { 694 int off = hlen, nh = ip->ip_p; 695 696 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 697 return; 698 } 699 bad: 700 m_freem(m); 701 } 702 703 /* 704 * Take incoming datagram fragment and try to 705 * reassemble it into whole datagram. If a chain for 706 * reassembly of this datagram already exists, then it 707 * is given as fp; otherwise have to make a chain. 708 */ 709 struct mbuf * 710 ip_reass(ipqe, fp) 711 struct ipqent *ipqe; 712 struct ipq *fp; 713 { 714 struct mbuf *m = ipqe->ipqe_m; 715 struct ipqent *nq, *p, *q; 716 struct ip *ip; 717 struct mbuf *t; 718 int hlen = ipqe->ipqe_ip->ip_hl << 2; 719 int i, next; 720 721 IPQ_LOCK_CHECK(); 722 723 /* 724 * Presence of header sizes in mbufs 725 * would confuse code below. 726 */ 727 m->m_data += hlen; 728 m->m_len -= hlen; 729 730 /* 731 * If first fragment to arrive, create a reassembly queue. 732 */ 733 if (fp == 0) { 734 MALLOC(fp, struct ipq *, sizeof (struct ipq), 735 M_FTABLE, M_NOWAIT); 736 if (fp == NULL) 737 goto dropfrag; 738 LIST_INSERT_HEAD(&ipq, fp, ipq_q); 739 fp->ipq_ttl = IPFRAGTTL; 740 fp->ipq_p = ipqe->ipqe_ip->ip_p; 741 fp->ipq_id = ipqe->ipqe_ip->ip_id; 742 LIST_INIT(&fp->ipq_fragq); 743 fp->ipq_src = ipqe->ipqe_ip->ip_src; 744 fp->ipq_dst = ipqe->ipqe_ip->ip_dst; 745 p = NULL; 746 goto insert; 747 } 748 749 /* 750 * Find a segment which begins after this one does. 751 */ 752 for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL; 753 p = q, q = q->ipqe_q.le_next) 754 if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off) 755 break; 756 757 /* 758 * If there is a preceding segment, it may provide some of 759 * our data already. If so, drop the data from the incoming 760 * segment. If it provides all of our data, drop us. 761 */ 762 if (p != NULL) { 763 i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len - 764 ipqe->ipqe_ip->ip_off; 765 if (i > 0) { 766 if (i >= ipqe->ipqe_ip->ip_len) 767 goto dropfrag; 768 m_adj(ipqe->ipqe_m, i); 769 ipqe->ipqe_ip->ip_off += i; 770 ipqe->ipqe_ip->ip_len -= i; 771 } 772 } 773 774 /* 775 * While we overlap succeeding segments trim them or, 776 * if they are completely covered, dequeue them. 777 */ 778 for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len > 779 q->ipqe_ip->ip_off; q = nq) { 780 i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) - 781 q->ipqe_ip->ip_off; 782 if (i < q->ipqe_ip->ip_len) { 783 q->ipqe_ip->ip_len -= i; 784 q->ipqe_ip->ip_off += i; 785 m_adj(q->ipqe_m, i); 786 break; 787 } 788 nq = q->ipqe_q.le_next; 789 m_freem(q->ipqe_m); 790 LIST_REMOVE(q, ipqe_q); 791 pool_put(&ipqent_pool, q); 792 } 793 794 insert: 795 /* 796 * Stick new segment in its place; 797 * check for complete reassembly. 798 */ 799 if (p == NULL) { 800 LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); 801 } else { 802 LIST_INSERT_AFTER(p, ipqe, ipqe_q); 803 } 804 next = 0; 805 for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL; 806 p = q, q = q->ipqe_q.le_next) { 807 if (q->ipqe_ip->ip_off != next) 808 return (0); 809 next += q->ipqe_ip->ip_len; 810 } 811 if (p->ipqe_mff) 812 return (0); 813 814 /* 815 * Reassembly is complete. Check for a bogus message size and 816 * concatenate fragments. 817 */ 818 q = fp->ipq_fragq.lh_first; 819 ip = q->ipqe_ip; 820 if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) { 821 ipstat.ips_toolong++; 822 ip_freef(fp); 823 return (0); 824 } 825 m = q->ipqe_m; 826 t = m->m_next; 827 m->m_next = 0; 828 m_cat(m, t); 829 nq = q->ipqe_q.le_next; 830 pool_put(&ipqent_pool, q); 831 for (q = nq; q != NULL; q = nq) { 832 t = q->ipqe_m; 833 nq = q->ipqe_q.le_next; 834 pool_put(&ipqent_pool, q); 835 m_cat(m, t); 836 } 837 838 /* 839 * Create header for new ip packet by 840 * modifying header of first packet; 841 * dequeue and discard fragment reassembly header. 842 * Make header visible. 843 */ 844 ip->ip_len = next; 845 ip->ip_src = fp->ipq_src; 846 ip->ip_dst = fp->ipq_dst; 847 LIST_REMOVE(fp, ipq_q); 848 FREE(fp, M_FTABLE); 849 m->m_len += (ip->ip_hl << 2); 850 m->m_data -= (ip->ip_hl << 2); 851 /* some debugging cruft by sklower, below, will go away soon */ 852 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 853 int plen = 0; 854 for (t = m; t; t = t->m_next) 855 plen += t->m_len; 856 m->m_pkthdr.len = plen; 857 } 858 return (m); 859 860 dropfrag: 861 ipstat.ips_fragdropped++; 862 m_freem(m); 863 pool_put(&ipqent_pool, ipqe); 864 return (0); 865 } 866 867 /* 868 * Free a fragment reassembly header and all 869 * associated datagrams. 870 */ 871 void 872 ip_freef(fp) 873 struct ipq *fp; 874 { 875 struct ipqent *q, *p; 876 877 IPQ_LOCK_CHECK(); 878 879 for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) { 880 p = q->ipqe_q.le_next; 881 m_freem(q->ipqe_m); 882 LIST_REMOVE(q, ipqe_q); 883 pool_put(&ipqent_pool, q); 884 } 885 LIST_REMOVE(fp, ipq_q); 886 FREE(fp, M_FTABLE); 887 } 888 889 /* 890 * IP timer processing; 891 * if a timer expires on a reassembly 892 * queue, discard it. 893 */ 894 void 895 ip_slowtimo() 896 { 897 struct ipq *fp, *nfp; 898 int s = splsoftnet(); 899 900 IPQ_LOCK(); 901 for (fp = ipq.lh_first; fp != NULL; fp = nfp) { 902 nfp = fp->ipq_q.le_next; 903 if (--fp->ipq_ttl == 0) { 904 ipstat.ips_fragtimeout++; 905 ip_freef(fp); 906 } 907 } 908 IPQ_UNLOCK(); 909 #ifdef GATEWAY 910 ipflow_slowtimo(); 911 #endif 912 splx(s); 913 } 914 915 /* 916 * Drain off all datagram fragments. 917 */ 918 void 919 ip_drain() 920 { 921 922 /* 923 * We may be called from a device's interrupt context. If 924 * the ipq is already busy, just bail out now. 925 */ 926 if (ipq_lock_try() == 0) 927 return; 928 929 while (ipq.lh_first != NULL) { 930 ipstat.ips_fragdropped++; 931 ip_freef(ipq.lh_first); 932 } 933 934 IPQ_UNLOCK(); 935 } 936 937 /* 938 * Do option processing on a datagram, 939 * possibly discarding it if bad options are encountered, 940 * or forwarding it if source-routed. 941 * Returns 1 if packet has been forwarded/freed, 942 * 0 if the packet should be processed further. 943 */ 944 int 945 ip_dooptions(m) 946 struct mbuf *m; 947 { 948 struct ip *ip = mtod(m, struct ip *); 949 u_char *cp, *cp0; 950 struct ip_timestamp *ipt; 951 struct in_ifaddr *ia; 952 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 953 struct in_addr dst; 954 n_time ntime; 955 956 dst = ip->ip_dst; 957 cp = (u_char *)(ip + 1); 958 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 959 for (; cnt > 0; cnt -= optlen, cp += optlen) { 960 opt = cp[IPOPT_OPTVAL]; 961 if (opt == IPOPT_EOL) 962 break; 963 if (opt == IPOPT_NOP) 964 optlen = 1; 965 else { 966 optlen = cp[IPOPT_OLEN]; 967 if (optlen <= 0 || optlen > cnt) { 968 code = &cp[IPOPT_OLEN] - (u_char *)ip; 969 goto bad; 970 } 971 } 972 switch (opt) { 973 974 default: 975 break; 976 977 /* 978 * Source routing with record. 979 * Find interface with current destination address. 980 * If none on this machine then drop if strictly routed, 981 * or do nothing if loosely routed. 982 * Record interface address and bring up next address 983 * component. If strictly routed make sure next 984 * address is on directly accessible net. 985 */ 986 case IPOPT_LSRR: 987 case IPOPT_SSRR: 988 if (ip_allowsrcrt == 0) { 989 type = ICMP_UNREACH; 990 code = ICMP_UNREACH_NET_PROHIB; 991 goto bad; 992 } 993 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 994 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 995 goto bad; 996 } 997 ipaddr.sin_addr = ip->ip_dst; 998 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); 999 if (ia == 0) { 1000 if (opt == IPOPT_SSRR) { 1001 type = ICMP_UNREACH; 1002 code = ICMP_UNREACH_SRCFAIL; 1003 goto bad; 1004 } 1005 /* 1006 * Loose routing, and not at next destination 1007 * yet; nothing to do except forward. 1008 */ 1009 break; 1010 } 1011 off--; /* 0 origin */ 1012 if (off > optlen - sizeof(struct in_addr)) { 1013 /* 1014 * End of source route. Should be for us. 1015 */ 1016 save_rte(cp, ip->ip_src); 1017 break; 1018 } 1019 /* 1020 * locate outgoing interface 1021 */ 1022 bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr, 1023 sizeof(ipaddr.sin_addr)); 1024 if (opt == IPOPT_SSRR) 1025 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); 1026 else 1027 ia = ip_rtaddr(ipaddr.sin_addr); 1028 if (ia == 0) { 1029 type = ICMP_UNREACH; 1030 code = ICMP_UNREACH_SRCFAIL; 1031 goto bad; 1032 } 1033 ip->ip_dst = ipaddr.sin_addr; 1034 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1035 (caddr_t)(cp + off), sizeof(struct in_addr)); 1036 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1037 /* 1038 * Let ip_intr's mcast routing check handle mcast pkts 1039 */ 1040 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1041 break; 1042 1043 case IPOPT_RR: 1044 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1045 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1046 goto bad; 1047 } 1048 /* 1049 * If no space remains, ignore. 1050 */ 1051 off--; /* 0 origin */ 1052 if (off > optlen - sizeof(struct in_addr)) 1053 break; 1054 bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr, 1055 sizeof(ipaddr.sin_addr)); 1056 /* 1057 * locate outgoing interface; if we're the destination, 1058 * use the incoming interface (should be same). 1059 */ 1060 if ((ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)))) 1061 == NULL && 1062 (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) { 1063 type = ICMP_UNREACH; 1064 code = ICMP_UNREACH_HOST; 1065 goto bad; 1066 } 1067 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1068 (caddr_t)(cp + off), sizeof(struct in_addr)); 1069 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1070 break; 1071 1072 case IPOPT_TS: 1073 code = cp - (u_char *)ip; 1074 ipt = (struct ip_timestamp *)cp; 1075 if (ipt->ipt_len < 5) 1076 goto bad; 1077 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) { 1078 if (++ipt->ipt_oflw == 0) 1079 goto bad; 1080 break; 1081 } 1082 cp0 = (cp + ipt->ipt_ptr - 1); 1083 switch (ipt->ipt_flg) { 1084 1085 case IPOPT_TS_TSONLY: 1086 break; 1087 1088 case IPOPT_TS_TSANDADDR: 1089 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1090 sizeof(struct in_addr) > ipt->ipt_len) 1091 goto bad; 1092 ipaddr.sin_addr = dst; 1093 ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr), 1094 m->m_pkthdr.rcvif)); 1095 if (ia == 0) 1096 continue; 1097 bcopy(&ia->ia_addr.sin_addr, 1098 cp0, sizeof(struct in_addr)); 1099 ipt->ipt_ptr += sizeof(struct in_addr); 1100 break; 1101 1102 case IPOPT_TS_PRESPEC: 1103 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1104 sizeof(struct in_addr) > ipt->ipt_len) 1105 goto bad; 1106 bcopy(cp0, &ipaddr.sin_addr, 1107 sizeof(struct in_addr)); 1108 if (ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))) 1109 == NULL) 1110 continue; 1111 ipt->ipt_ptr += sizeof(struct in_addr); 1112 break; 1113 1114 default: 1115 goto bad; 1116 } 1117 ntime = iptime(); 1118 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1119 bcopy(cp0, (caddr_t)cp + ipt->ipt_ptr - 1, 1120 sizeof(n_time)); 1121 ipt->ipt_ptr += sizeof(n_time); 1122 } 1123 } 1124 if (forward) { 1125 if (ip_forwsrcrt == 0) { 1126 type = ICMP_UNREACH; 1127 code = ICMP_UNREACH_SRCFAIL; 1128 goto bad; 1129 } 1130 ip_forward(m, 1); 1131 return (1); 1132 } 1133 return (0); 1134 bad: 1135 icmp_error(m, type, code, 0, 0); 1136 ipstat.ips_badoptions++; 1137 return (1); 1138 } 1139 1140 /* 1141 * Given address of next destination (final or next hop), 1142 * return internet address info of interface to be used to get there. 1143 */ 1144 struct in_ifaddr * 1145 ip_rtaddr(dst) 1146 struct in_addr dst; 1147 { 1148 struct sockaddr_in *sin; 1149 1150 sin = satosin(&ipforward_rt.ro_dst); 1151 1152 if (ipforward_rt.ro_rt == 0 || !in_hosteq(dst, sin->sin_addr)) { 1153 if (ipforward_rt.ro_rt) { 1154 RTFREE(ipforward_rt.ro_rt); 1155 ipforward_rt.ro_rt = 0; 1156 } 1157 sin->sin_family = AF_INET; 1158 sin->sin_len = sizeof(*sin); 1159 sin->sin_addr = dst; 1160 1161 rtalloc(&ipforward_rt); 1162 } 1163 if (ipforward_rt.ro_rt == 0) 1164 return ((struct in_ifaddr *)0); 1165 return (ifatoia(ipforward_rt.ro_rt->rt_ifa)); 1166 } 1167 1168 /* 1169 * Save incoming source route for use in replies, 1170 * to be picked up later by ip_srcroute if the receiver is interested. 1171 */ 1172 void 1173 save_rte(option, dst) 1174 u_char *option; 1175 struct in_addr dst; 1176 { 1177 unsigned olen; 1178 1179 olen = option[IPOPT_OLEN]; 1180 #ifdef DIAGNOSTIC 1181 if (ipprintfs) 1182 printf("save_rte: olen %d\n", olen); 1183 #endif /* 0 */ 1184 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1185 return; 1186 bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen); 1187 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1188 ip_srcrt.dst = dst; 1189 } 1190 1191 /* 1192 * Retrieve incoming source route for use in replies, 1193 * in the same form used by setsockopt. 1194 * The first hop is placed before the options, will be removed later. 1195 */ 1196 struct mbuf * 1197 ip_srcroute() 1198 { 1199 struct in_addr *p, *q; 1200 struct mbuf *m; 1201 1202 if (ip_nhops == 0) 1203 return ((struct mbuf *)0); 1204 m = m_get(M_DONTWAIT, MT_SOOPTS); 1205 if (m == 0) 1206 return ((struct mbuf *)0); 1207 1208 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1209 1210 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1211 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1212 OPTSIZ; 1213 #ifdef DIAGNOSTIC 1214 if (ipprintfs) 1215 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1216 #endif 1217 1218 /* 1219 * First save first hop for return route 1220 */ 1221 p = &ip_srcrt.route[ip_nhops - 1]; 1222 *(mtod(m, struct in_addr *)) = *p--; 1223 #ifdef DIAGNOSTIC 1224 if (ipprintfs) 1225 printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1226 #endif 1227 1228 /* 1229 * Copy option fields and padding (nop) to mbuf. 1230 */ 1231 ip_srcrt.nop = IPOPT_NOP; 1232 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1233 bcopy((caddr_t)&ip_srcrt.nop, 1234 mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ); 1235 q = (struct in_addr *)(mtod(m, caddr_t) + 1236 sizeof(struct in_addr) + OPTSIZ); 1237 #undef OPTSIZ 1238 /* 1239 * Record return path as an IP source route, 1240 * reversing the path (pointers are now aligned). 1241 */ 1242 while (p >= ip_srcrt.route) { 1243 #ifdef DIAGNOSTIC 1244 if (ipprintfs) 1245 printf(" %x", ntohl(q->s_addr)); 1246 #endif 1247 *q++ = *p--; 1248 } 1249 /* 1250 * Last hop goes to final destination. 1251 */ 1252 *q = ip_srcrt.dst; 1253 #ifdef DIAGNOSTIC 1254 if (ipprintfs) 1255 printf(" %x\n", ntohl(q->s_addr)); 1256 #endif 1257 return (m); 1258 } 1259 1260 /* 1261 * Strip out IP options, at higher 1262 * level protocol in the kernel. 1263 * Second argument is buffer to which options 1264 * will be moved, and return value is their length. 1265 * XXX should be deleted; last arg currently ignored. 1266 */ 1267 void 1268 ip_stripoptions(m, mopt) 1269 struct mbuf *m; 1270 struct mbuf *mopt; 1271 { 1272 int i; 1273 struct ip *ip = mtod(m, struct ip *); 1274 caddr_t opts; 1275 int olen; 1276 1277 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1278 opts = (caddr_t)(ip + 1); 1279 i = m->m_len - (sizeof (struct ip) + olen); 1280 bcopy(opts + olen, opts, (unsigned)i); 1281 m->m_len -= olen; 1282 if (m->m_flags & M_PKTHDR) 1283 m->m_pkthdr.len -= olen; 1284 ip->ip_len -= olen; 1285 ip->ip_hl = sizeof (struct ip) >> 2; 1286 } 1287 1288 int inetctlerrmap[PRC_NCMDS] = { 1289 0, 0, 0, 0, 1290 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1291 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1292 EMSGSIZE, EHOSTUNREACH, 0, 0, 1293 0, 0, 0, 0, 1294 ENOPROTOOPT 1295 }; 1296 1297 /* 1298 * Forward a packet. If some error occurs return the sender 1299 * an icmp packet. Note we can't always generate a meaningful 1300 * icmp message because icmp doesn't have a large enough repertoire 1301 * of codes and types. 1302 * 1303 * If not forwarding, just drop the packet. This could be confusing 1304 * if ipforwarding was zero but some routing protocol was advancing 1305 * us as a gateway to somewhere. However, we must let the routing 1306 * protocol deal with that. 1307 * 1308 * The srcrt parameter indicates whether the packet is being forwarded 1309 * via a source route. 1310 */ 1311 void 1312 ip_forward(m, srcrt) 1313 struct mbuf *m; 1314 int srcrt; 1315 { 1316 struct ip *ip = mtod(m, struct ip *); 1317 struct sockaddr_in *sin; 1318 struct rtentry *rt; 1319 int error, type = 0, code = 0; 1320 struct mbuf *mcopy; 1321 n_long dest; 1322 struct ifnet *destifp; 1323 #ifdef IPSEC 1324 struct ifnet dummyifp; 1325 #endif 1326 1327 dest = 0; 1328 #ifdef DIAGNOSTIC 1329 if (ipprintfs) 1330 printf("forward: src %2.2x dst %2.2x ttl %x\n", 1331 ntohl(ip->ip_src.s_addr), 1332 ntohl(ip->ip_dst.s_addr), ip->ip_ttl); 1333 #endif 1334 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1335 ipstat.ips_cantforward++; 1336 m_freem(m); 1337 return; 1338 } 1339 if (ip->ip_ttl <= IPTTLDEC) { 1340 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1341 return; 1342 } 1343 ip->ip_ttl -= IPTTLDEC; 1344 1345 sin = satosin(&ipforward_rt.ro_dst); 1346 if ((rt = ipforward_rt.ro_rt) == 0 || 1347 !in_hosteq(ip->ip_dst, sin->sin_addr)) { 1348 if (ipforward_rt.ro_rt) { 1349 RTFREE(ipforward_rt.ro_rt); 1350 ipforward_rt.ro_rt = 0; 1351 } 1352 sin->sin_family = AF_INET; 1353 sin->sin_len = sizeof(struct sockaddr_in); 1354 sin->sin_addr = ip->ip_dst; 1355 1356 rtalloc(&ipforward_rt); 1357 if (ipforward_rt.ro_rt == 0) { 1358 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1359 return; 1360 } 1361 rt = ipforward_rt.ro_rt; 1362 } 1363 1364 /* 1365 * Save at most 68 bytes of the packet in case 1366 * we need to generate an ICMP message to the src. 1367 */ 1368 mcopy = m_copy(m, 0, imin((int)ip->ip_len, 68)); 1369 1370 /* 1371 * If forwarding packet using same interface that it came in on, 1372 * perhaps should send a redirect to sender to shortcut a hop. 1373 * Only send redirect if source is sending directly to us, 1374 * and if packet was not source routed (or has any options). 1375 * Also, don't send redirect if forwarding using a default route 1376 * or a route modified by a redirect. 1377 */ 1378 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1379 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1380 !in_nullhost(satosin(rt_key(rt))->sin_addr) && 1381 ipsendredirects && !srcrt) { 1382 if (rt->rt_ifa && 1383 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1384 ifatoia(rt->rt_ifa)->ia_subnet) { 1385 if (rt->rt_flags & RTF_GATEWAY) 1386 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1387 else 1388 dest = ip->ip_dst.s_addr; 1389 /* 1390 * Router requirements says to only send host 1391 * redirects. 1392 */ 1393 type = ICMP_REDIRECT; 1394 code = ICMP_REDIRECT_HOST; 1395 #ifdef DIAGNOSTIC 1396 if (ipprintfs) 1397 printf("redirect (%d) to %x\n", code, 1398 (u_int32_t)dest); 1399 #endif 1400 } 1401 } 1402 1403 #ifdef IPSEC 1404 /* Don't lookup socket in forwading case */ 1405 ipsec_setsocket(m, NULL); 1406 #endif 1407 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1408 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 0); 1409 if (error) 1410 ipstat.ips_cantforward++; 1411 else { 1412 ipstat.ips_forward++; 1413 if (type) 1414 ipstat.ips_redirectsent++; 1415 else { 1416 if (mcopy) { 1417 #ifdef GATEWAY 1418 if (mcopy->m_flags & M_CANFASTFWD) 1419 ipflow_create(&ipforward_rt, mcopy); 1420 #endif 1421 m_freem(mcopy); 1422 } 1423 return; 1424 } 1425 } 1426 if (mcopy == NULL) 1427 return; 1428 destifp = NULL; 1429 1430 switch (error) { 1431 1432 case 0: /* forwarded, but need redirect */ 1433 /* type, code set above */ 1434 break; 1435 1436 case ENETUNREACH: /* shouldn't happen, checked above */ 1437 case EHOSTUNREACH: 1438 case ENETDOWN: 1439 case EHOSTDOWN: 1440 default: 1441 type = ICMP_UNREACH; 1442 code = ICMP_UNREACH_HOST; 1443 break; 1444 1445 case EMSGSIZE: 1446 type = ICMP_UNREACH; 1447 code = ICMP_UNREACH_NEEDFRAG; 1448 #ifndef IPSEC 1449 if (ipforward_rt.ro_rt) 1450 destifp = ipforward_rt.ro_rt->rt_ifp; 1451 #else 1452 /* 1453 * If the packet is routed over IPsec tunnel, tell the 1454 * originator the tunnel MTU. 1455 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1456 * XXX quickhack!!! 1457 */ 1458 if (ipforward_rt.ro_rt) { 1459 struct secpolicy *sp; 1460 int ipsecerror; 1461 size_t ipsechdr; 1462 struct route *ro; 1463 1464 sp = ipsec4_getpolicybyaddr(mcopy, 1465 IPSEC_DIR_OUTBOUND, 1466 IP_FORWARDING, 1467 &ipsecerror); 1468 1469 if (sp == NULL) 1470 destifp = ipforward_rt.ro_rt->rt_ifp; 1471 else { 1472 /* count IPsec header size */ 1473 ipsechdr = ipsec4_hdrsiz(mcopy, 1474 IPSEC_DIR_OUTBOUND, 1475 NULL); 1476 1477 /* 1478 * find the correct route for outer IPv4 1479 * header, compute tunnel MTU. 1480 * 1481 * XXX BUG ALERT 1482 * The "dummyifp" code relies upon the fact 1483 * that icmp_error() touches only ifp->if_mtu. 1484 */ 1485 /*XXX*/ 1486 destifp = NULL; 1487 if (sp->req != NULL 1488 && sp->req->sav != NULL 1489 && sp->req->sav->sah != NULL) { 1490 ro = &sp->req->sav->sah->sa_route; 1491 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1492 dummyifp.if_mtu = 1493 ro->ro_rt->rt_ifp->if_mtu; 1494 dummyifp.if_mtu -= ipsechdr; 1495 destifp = &dummyifp; 1496 } 1497 } 1498 1499 key_freesp(sp); 1500 } 1501 } 1502 #endif /*IPSEC*/ 1503 ipstat.ips_cantfrag++; 1504 break; 1505 1506 case ENOBUFS: 1507 type = ICMP_SOURCEQUENCH; 1508 code = 0; 1509 break; 1510 } 1511 icmp_error(mcopy, type, code, dest, destifp); 1512 } 1513 1514 void 1515 ip_savecontrol(inp, mp, ip, m) 1516 struct inpcb *inp; 1517 struct mbuf **mp; 1518 struct ip *ip; 1519 struct mbuf *m; 1520 { 1521 1522 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1523 struct timeval tv; 1524 1525 microtime(&tv); 1526 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1527 SCM_TIMESTAMP, SOL_SOCKET); 1528 if (*mp) 1529 mp = &(*mp)->m_next; 1530 } 1531 if (inp->inp_flags & INP_RECVDSTADDR) { 1532 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1533 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1534 if (*mp) 1535 mp = &(*mp)->m_next; 1536 } 1537 #ifdef notyet 1538 /* 1539 * XXX 1540 * Moving these out of udp_input() made them even more broken 1541 * than they already were. 1542 * - fenner (at) parc.xerox.com 1543 */ 1544 /* options were tossed already */ 1545 if (inp->inp_flags & INP_RECVOPTS) { 1546 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1547 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1548 if (*mp) 1549 mp = &(*mp)->m_next; 1550 } 1551 /* ip_srcroute doesn't do what we want here, need to fix */ 1552 if (inp->inp_flags & INP_RECVRETOPTS) { 1553 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1554 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1555 if (*mp) 1556 mp = &(*mp)->m_next; 1557 } 1558 #endif 1559 if (inp->inp_flags & INP_RECVIF) { 1560 struct sockaddr_dl sdl; 1561 1562 sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]); 1563 sdl.sdl_family = AF_LINK; 1564 sdl.sdl_index = m->m_pkthdr.rcvif ? 1565 m->m_pkthdr.rcvif->if_index : 0; 1566 sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0; 1567 *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len, 1568 IP_RECVIF, IPPROTO_IP); 1569 if (*mp) 1570 mp = &(*mp)->m_next; 1571 } 1572 } 1573 1574 int 1575 ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 1576 int *name; 1577 u_int namelen; 1578 void *oldp; 1579 size_t *oldlenp; 1580 void *newp; 1581 size_t newlen; 1582 { 1583 extern int subnetsarelocal, hostzeroisbroadcast; 1584 1585 int error, old; 1586 1587 /* All sysctl names at this level are terminal. */ 1588 if (namelen != 1) 1589 return (ENOTDIR); 1590 1591 switch (name[0]) { 1592 case IPCTL_FORWARDING: 1593 return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding)); 1594 case IPCTL_SENDREDIRECTS: 1595 return (sysctl_int(oldp, oldlenp, newp, newlen, 1596 &ipsendredirects)); 1597 case IPCTL_DEFTTL: 1598 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl)); 1599 #ifdef notyet 1600 case IPCTL_DEFMTU: 1601 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu)); 1602 #endif 1603 case IPCTL_FORWSRCRT: 1604 /* Don't allow this to change in a secure environment. */ 1605 if (securelevel > 0) 1606 return (sysctl_rdint(oldp, oldlenp, newp, 1607 ip_forwsrcrt)); 1608 else 1609 return (sysctl_int(oldp, oldlenp, newp, newlen, 1610 &ip_forwsrcrt)); 1611 case IPCTL_DIRECTEDBCAST: 1612 return (sysctl_int(oldp, oldlenp, newp, newlen, 1613 &ip_directedbcast)); 1614 case IPCTL_ALLOWSRCRT: 1615 return (sysctl_int(oldp, oldlenp, newp, newlen, 1616 &ip_allowsrcrt)); 1617 case IPCTL_SUBNETSARELOCAL: 1618 return (sysctl_int(oldp, oldlenp, newp, newlen, 1619 &subnetsarelocal)); 1620 case IPCTL_MTUDISC: 1621 error = sysctl_int(oldp, oldlenp, newp, newlen, 1622 &ip_mtudisc); 1623 if (ip_mtudisc != 0 && ip_mtudisc_timeout_q == NULL) { 1624 ip_mtudisc_timeout_q = 1625 rt_timer_queue_create(ip_mtudisc_timeout); 1626 } else if (ip_mtudisc == 0 && ip_mtudisc_timeout_q != NULL) { 1627 rt_timer_queue_destroy(ip_mtudisc_timeout_q, TRUE); 1628 ip_mtudisc_timeout_q = NULL; 1629 } 1630 return error; 1631 case IPCTL_ANONPORTMIN: 1632 old = anonportmin; 1633 error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmin); 1634 if (anonportmin >= anonportmax || anonportmin > 65535 1635 #ifndef IPNOPRIVPORTS 1636 || anonportmin < IPPORT_RESERVED 1637 #endif 1638 ) { 1639 anonportmin = old; 1640 return (EINVAL); 1641 } 1642 return (error); 1643 case IPCTL_ANONPORTMAX: 1644 old = anonportmax; 1645 error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmax); 1646 if (anonportmin >= anonportmax || anonportmax > 65535 1647 #ifndef IPNOPRIVPORTS 1648 || anonportmax < IPPORT_RESERVED 1649 #endif 1650 ) { 1651 anonportmax = old; 1652 return (EINVAL); 1653 } 1654 return (error); 1655 case IPCTL_MTUDISCTIMEOUT: 1656 error = sysctl_int(oldp, oldlenp, newp, newlen, 1657 &ip_mtudisc_timeout); 1658 if (ip_mtudisc_timeout_q != NULL) 1659 rt_timer_queue_change(ip_mtudisc_timeout_q, 1660 ip_mtudisc_timeout); 1661 return (error); 1662 #ifdef GATEWAY 1663 case IPCTL_MAXFLOWS: 1664 { 1665 int s; 1666 1667 error = sysctl_int(oldp, oldlenp, newp, newlen, 1668 &ip_maxflows); 1669 s = splsoftnet(); 1670 ipflow_reap(0); 1671 splx(s); 1672 return (error); 1673 } 1674 #endif 1675 case IPCTL_HOSTZEROBROADCAST: 1676 return (sysctl_int(oldp, oldlenp, newp, newlen, 1677 &hostzeroisbroadcast)); 1678 #if NGIF > 0 1679 case IPCTL_GIF_TTL: 1680 return(sysctl_int(oldp, oldlenp, newp, newlen, 1681 &ip_gif_ttl)); 1682 #endif 1683 1684 default: 1685 return (EOPNOTSUPP); 1686 } 1687 /* NOTREACHED */ 1688 } 1689
Indexes created Fri Sep 26 08:10:20 GMT 2025