ip_input.c revision 1.154
1/* $NetBSD: ip_input.c,v 1.154 2002/06/30 22:40:34 thorpej 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 <sys/cdefs.h> 105__KERNEL_RCSID(0, "$NetBSD: ip_input.c,v 1.154 2002/06/30 22:40:34 thorpej Exp $"); 106 107#include "opt_gateway.h" 108#include "opt_pfil_hooks.h" 109#include "opt_ipsec.h" 110#include "opt_mrouting.h" 111#include "opt_inet_csum.h" 112 113#include <sys/param.h> 114#include <sys/systm.h> 115#include <sys/malloc.h> 116#include <sys/mbuf.h> 117#include <sys/domain.h> 118#include <sys/protosw.h> 119#include <sys/socket.h> 120#include <sys/socketvar.h> 121#include <sys/errno.h> 122#include <sys/time.h> 123#include <sys/kernel.h> 124#include <sys/pool.h> 125#include <sys/sysctl.h> 126 127#include <net/if.h> 128#include <net/if_dl.h> 129#include <net/route.h> 130#include <net/pfil.h> 131 132#include <netinet/in.h> 133#include <netinet/in_systm.h> 134#include <netinet/ip.h> 135#include <netinet/in_pcb.h> 136#include <netinet/in_var.h> 137#include <netinet/ip_var.h> 138#include <netinet/ip_icmp.h> 139/* just for gif_ttl */ 140#include <netinet/in_gif.h> 141#include "gif.h" 142#include <net/if_gre.h> 143#include "gre.h" 144 145#ifdef MROUTING 146#include <netinet/ip_mroute.h> 147#endif 148 149#ifdef IPSEC 150#include <netinet6/ipsec.h> 151#include <netkey/key.h> 152#endif 153 154#ifndef IPFORWARDING 155#ifdef GATEWAY 156#define IPFORWARDING 1 /* forward IP packets not for us */ 157#else /* GATEWAY */ 158#define IPFORWARDING 0 /* don't forward IP packets not for us */ 159#endif /* GATEWAY */ 160#endif /* IPFORWARDING */ 161#ifndef IPSENDREDIRECTS 162#define IPSENDREDIRECTS 1 163#endif 164#ifndef IPFORWSRCRT 165#define IPFORWSRCRT 1 /* forward source-routed packets */ 166#endif 167#ifndef IPALLOWSRCRT 168#define IPALLOWSRCRT 1 /* allow source-routed packets */ 169#endif 170#ifndef IPMTUDISC 171#define IPMTUDISC 1 172#endif 173#ifndef IPMTUDISCTIMEOUT 174#define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */ 175#endif 176 177/* 178 * Note: DIRECTED_BROADCAST is handled this way so that previous 179 * configuration using this option will Just Work. 180 */ 181#ifndef IPDIRECTEDBCAST 182#ifdef DIRECTED_BROADCAST 183#define IPDIRECTEDBCAST 1 184#else 185#define IPDIRECTEDBCAST 0 186#endif /* DIRECTED_BROADCAST */ 187#endif /* IPDIRECTEDBCAST */ 188int ipforwarding = IPFORWARDING; 189int ipsendredirects = IPSENDREDIRECTS; 190int ip_defttl = IPDEFTTL; 191int ip_forwsrcrt = IPFORWSRCRT; 192int ip_directedbcast = IPDIRECTEDBCAST; 193int ip_allowsrcrt = IPALLOWSRCRT; 194int ip_mtudisc = IPMTUDISC; 195u_int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 196#ifdef DIAGNOSTIC 197int ipprintfs = 0; 198#endif 199 200struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 201 202extern struct domain inetdomain; 203int ipqmaxlen = IFQ_MAXLEN; 204u_long in_ifaddrhash; /* size of hash table - 1 */ 205int in_ifaddrentries; /* total number of addrs */ 206struct in_ifaddrhead in_ifaddr; 207struct in_ifaddrhashhead *in_ifaddrhashtbl; 208struct ifqueue ipintrq; 209struct ipstat ipstat; 210u_int16_t ip_id; 211 212#ifdef PFIL_HOOKS 213struct pfil_head inet_pfil_hook; 214#endif 215 216struct ipqhead ipq; 217int ipq_locked; 218int ip_nfragpackets = 0; 219int ip_maxfragpackets = 200; 220 221static __inline int ipq_lock_try __P((void)); 222static __inline void ipq_unlock __P((void)); 223 224static __inline int 225ipq_lock_try() 226{ 227 int s; 228 229 /* 230 * Use splvm() -- we're blocking things that would cause 231 * mbuf allocation. 232 */ 233 s = splvm(); 234 if (ipq_locked) { 235 splx(s); 236 return (0); 237 } 238 ipq_locked = 1; 239 splx(s); 240 return (1); 241} 242 243static __inline void 244ipq_unlock() 245{ 246 int s; 247 248 s = splvm(); 249 ipq_locked = 0; 250 splx(s); 251} 252 253#ifdef DIAGNOSTIC 254#define IPQ_LOCK() \ 255do { \ 256 if (ipq_lock_try() == 0) { \ 257 printf("%s:%d: ipq already locked\n", __FILE__, __LINE__); \ 258 panic("ipq_lock"); \ 259 } \ 260} while (0) 261#define IPQ_LOCK_CHECK() \ 262do { \ 263 if (ipq_locked == 0) { \ 264 printf("%s:%d: ipq lock not held\n", __FILE__, __LINE__); \ 265 panic("ipq lock check"); \ 266 } \ 267} while (0) 268#else 269#define IPQ_LOCK() (void) ipq_lock_try() 270#define IPQ_LOCK_CHECK() /* nothing */ 271#endif 272 273#define IPQ_UNLOCK() ipq_unlock() 274 275struct pool ipqent_pool; 276 277#ifdef INET_CSUM_COUNTERS 278#include <sys/device.h> 279 280struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 281 NULL, "inet", "hwcsum bad"); 282struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 283 NULL, "inet", "hwcsum ok"); 284struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 285 NULL, "inet", "swcsum"); 286 287#define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 288 289#else 290 291#define INET_CSUM_COUNTER_INCR(ev) /* nothing */ 292 293#endif /* INET_CSUM_COUNTERS */ 294 295/* 296 * We need to save the IP options in case a protocol wants to respond 297 * to an incoming packet over the same route if the packet got here 298 * using IP source routing. This allows connection establishment and 299 * maintenance when the remote end is on a network that is not known 300 * to us. 301 */ 302int ip_nhops = 0; 303static struct ip_srcrt { 304 struct in_addr dst; /* final destination */ 305 char nop; /* one NOP to align */ 306 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 307 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 308} ip_srcrt; 309 310static void save_rte __P((u_char *, struct in_addr)); 311 312/* 313 * IP initialization: fill in IP protocol switch table. 314 * All protocols not implemented in kernel go to raw IP protocol handler. 315 */ 316void 317ip_init() 318{ 319 struct protosw *pr; 320 int i; 321 322 pool_init(&ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl", 323 NULL); 324 325 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 326 if (pr == 0) 327 panic("ip_init"); 328 for (i = 0; i < IPPROTO_MAX; i++) 329 ip_protox[i] = pr - inetsw; 330 for (pr = inetdomain.dom_protosw; 331 pr < inetdomain.dom_protoswNPROTOSW; pr++) 332 if (pr->pr_domain->dom_family == PF_INET && 333 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 334 ip_protox[pr->pr_protocol] = pr - inetsw; 335 LIST_INIT(&ipq); 336 ip_id = time.tv_sec & 0xffff; 337 ipintrq.ifq_maxlen = ipqmaxlen; 338 TAILQ_INIT(&in_ifaddr); 339 in_ifaddrhashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IFADDR, 340 M_WAITOK, &in_ifaddrhash); 341 if (ip_mtudisc != 0) 342 ip_mtudisc_timeout_q = 343 rt_timer_queue_create(ip_mtudisc_timeout); 344#ifdef GATEWAY 345 ipflow_init(); 346#endif 347 348#ifdef PFIL_HOOKS 349 /* Register our Packet Filter hook. */ 350 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 351 inet_pfil_hook.ph_af = AF_INET; 352 i = pfil_head_register(&inet_pfil_hook); 353 if (i != 0) 354 printf("ip_init: WARNING: unable to register pfil hook, " 355 "error %d\n", i); 356#endif /* PFIL_HOOKS */ 357 358#ifdef INET_CSUM_COUNTERS 359 evcnt_attach_static(&ip_hwcsum_bad); 360 evcnt_attach_static(&ip_hwcsum_ok); 361 evcnt_attach_static(&ip_swcsum); 362#endif /* INET_CSUM_COUNTERS */ 363} 364 365struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 366struct route ipforward_rt; 367 368/* 369 * IP software interrupt routine 370 */ 371void 372ipintr() 373{ 374 int s; 375 struct mbuf *m; 376 377 while (1) { 378 s = splnet(); 379 IF_DEQUEUE(&ipintrq, m); 380 splx(s); 381 if (m == 0) 382 return; 383 ip_input(m); 384 } 385} 386 387/* 388 * Ip input routine. Checksum and byte swap header. If fragmented 389 * try to reassemble. Process options. Pass to next level. 390 */ 391void 392ip_input(struct mbuf *m) 393{ 394 struct ip *ip = NULL; 395 struct ipq *fp; 396 struct in_ifaddr *ia; 397 struct ifaddr *ifa; 398 struct ipqent *ipqe; 399 int hlen = 0, mff, len; 400 int downmatch; 401 402#ifdef DIAGNOSTIC 403 if ((m->m_flags & M_PKTHDR) == 0) 404 panic("ipintr no HDR"); 405#endif 406#ifdef IPSEC 407 /* 408 * should the inner packet be considered authentic? 409 * see comment in ah4_input(). 410 */ 411 if (m) { 412 m->m_flags &= ~M_AUTHIPHDR; 413 m->m_flags &= ~M_AUTHIPDGM; 414 } 415#endif 416 /* 417 * If no IP addresses have been set yet but the interfaces 418 * are receiving, can't do anything with incoming packets yet. 419 */ 420 if (TAILQ_FIRST(&in_ifaddr) == 0) 421 goto bad; 422 ipstat.ips_total++; 423 /* 424 * If the IP header is not aligned, slurp it up into a new 425 * mbuf with space for link headers, in the event we forward 426 * it. Otherwise, if it is aligned, make sure the entire 427 * base IP header is in the first mbuf of the chain. 428 */ 429 if (IP_HDR_ALIGNED_P(mtod(m, caddr_t)) == 0) { 430 if ((m = m_copyup(m, sizeof(struct ip), 431 (max_linkhdr + 3) & ~3)) == NULL) { 432 /* XXXJRT new stat, please */ 433 ipstat.ips_toosmall++; 434 return; 435 } 436 } else if (__predict_false(m->m_len < sizeof (struct ip))) { 437 if ((m = m_pullup(m, sizeof (struct ip))) == NULL) { 438 ipstat.ips_toosmall++; 439 return; 440 } 441 } 442 ip = mtod(m, struct ip *); 443 if (ip->ip_v != IPVERSION) { 444 ipstat.ips_badvers++; 445 goto bad; 446 } 447 hlen = ip->ip_hl << 2; 448 if (hlen < sizeof(struct ip)) { /* minimum header length */ 449 ipstat.ips_badhlen++; 450 goto bad; 451 } 452 if (hlen > m->m_len) { 453 if ((m = m_pullup(m, hlen)) == 0) { 454 ipstat.ips_badhlen++; 455 return; 456 } 457 ip = mtod(m, struct ip *); 458 } 459 460 /* 461 * RFC1122: packets with a multicast source address are 462 * not allowed. 463 */ 464 if (IN_MULTICAST(ip->ip_src.s_addr)) { 465 ipstat.ips_badaddr++; 466 goto bad; 467 } 468 469 /* 127/8 must not appear on wire - RFC1122 */ 470 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 471 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 472 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 473 ipstat.ips_badaddr++; 474 goto bad; 475 } 476 } 477 478 switch (m->m_pkthdr.csum_flags & 479 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_IPv4) | 480 M_CSUM_IPv4_BAD)) { 481 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 482 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad); 483 goto badcsum; 484 485 case M_CSUM_IPv4: 486 /* Checksum was okay. */ 487 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok); 488 break; 489 490 default: 491 /* Must compute it ourselves. */ 492 INET_CSUM_COUNTER_INCR(&ip_swcsum); 493 if (in_cksum(m, hlen) != 0) 494 goto bad; 495 break; 496 } 497 498 /* Retrieve the packet length. */ 499 len = ntohs(ip->ip_len); 500 501 /* 502 * Check for additional length bogosity 503 */ 504 if (len < hlen) { 505 ipstat.ips_badlen++; 506 goto bad; 507 } 508 509 /* 510 * Check that the amount of data in the buffers 511 * is as at least much as the IP header would have us expect. 512 * Trim mbufs if longer than we expect. 513 * Drop packet if shorter than we expect. 514 */ 515 if (m->m_pkthdr.len < len) { 516 ipstat.ips_tooshort++; 517 goto bad; 518 } 519 if (m->m_pkthdr.len > len) { 520 if (m->m_len == m->m_pkthdr.len) { 521 m->m_len = len; 522 m->m_pkthdr.len = len; 523 } else 524 m_adj(m, len - m->m_pkthdr.len); 525 } 526 527#ifdef IPSEC 528 /* ipflow (IP fast forwarding) is not compatible with IPsec. */ 529 m->m_flags &= ~M_CANFASTFWD; 530#else 531 /* 532 * Assume that we can create a fast-forward IP flow entry 533 * based on this packet. 534 */ 535 m->m_flags |= M_CANFASTFWD; 536#endif 537 538#ifdef PFIL_HOOKS 539 /* 540 * Run through list of hooks for input packets. If there are any 541 * filters which require that additional packets in the flow are 542 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 543 * Note that filters must _never_ set this flag, as another filter 544 * in the list may have previously cleared it. 545 */ 546 /* 547 * let ipfilter look at packet on the wire, 548 * not the decapsulated packet. 549 */ 550#ifdef IPSEC 551 if (!ipsec_getnhist(m)) 552#else 553 if (1) 554#endif 555 { 556 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 557 PFIL_IN) != 0) 558 return; 559 if (m == NULL) 560 return; 561 ip = mtod(m, struct ip *); 562 hlen = ip->ip_hl << 2; 563 } 564#endif /* PFIL_HOOKS */ 565 566#ifdef ALTQ 567 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 568 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 569 /* packet dropped by traffic conditioner */ 570 return; 571 } 572#endif 573 574 /* 575 * Convert fields to host representation. 576 */ 577 NTOHS(ip->ip_len); 578 NTOHS(ip->ip_off); 579 580 /* 581 * Process options and, if not destined for us, 582 * ship it on. ip_dooptions returns 1 when an 583 * error was detected (causing an icmp message 584 * to be sent and the original packet to be freed). 585 */ 586 ip_nhops = 0; /* for source routed packets */ 587 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 588 return; 589 590 /* 591 * Check our list of addresses, to see if the packet is for us. 592 * 593 * Traditional 4.4BSD did not consult IFF_UP at all. 594 * The behavior here is to treat addresses on !IFF_UP interface 595 * as not mine. 596 */ 597 downmatch = 0; 598 LIST_FOREACH(ia, &IN_IFADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 599 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) { 600 if ((ia->ia_ifp->if_flags & IFF_UP) != 0) 601 break; 602 else 603 downmatch++; 604 } 605 } 606 if (ia != NULL) 607 goto ours; 608 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 609 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrlist, ifa_list) { 610 if (ifa->ifa_addr->sa_family != AF_INET) 611 continue; 612 ia = ifatoia(ifa); 613 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 614 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 615 /* 616 * Look for all-0's host part (old broadcast addr), 617 * either for subnet or net. 618 */ 619 ip->ip_dst.s_addr == ia->ia_subnet || 620 ip->ip_dst.s_addr == ia->ia_net) 621 goto ours; 622 /* 623 * An interface with IP address zero accepts 624 * all packets that arrive on that interface. 625 */ 626 if (in_nullhost(ia->ia_addr.sin_addr)) 627 goto ours; 628 } 629 } 630 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 631 struct in_multi *inm; 632#ifdef MROUTING 633 extern struct socket *ip_mrouter; 634 635 if (M_READONLY(m)) { 636 if ((m = m_pullup(m, hlen)) == 0) { 637 ipstat.ips_toosmall++; 638 return; 639 } 640 ip = mtod(m, struct ip *); 641 } 642 643 if (ip_mrouter) { 644 /* 645 * If we are acting as a multicast router, all 646 * incoming multicast packets are passed to the 647 * kernel-level multicast forwarding function. 648 * The packet is returned (relatively) intact; if 649 * ip_mforward() returns a non-zero value, the packet 650 * must be discarded, else it may be accepted below. 651 * 652 * (The IP ident field is put in the same byte order 653 * as expected when ip_mforward() is called from 654 * ip_output().) 655 */ 656 if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) { 657 ipstat.ips_cantforward++; 658 m_freem(m); 659 return; 660 } 661 662 /* 663 * The process-level routing demon needs to receive 664 * all multicast IGMP packets, whether or not this 665 * host belongs to their destination groups. 666 */ 667 if (ip->ip_p == IPPROTO_IGMP) 668 goto ours; 669 ipstat.ips_forward++; 670 } 671#endif 672 /* 673 * See if we belong to the destination multicast group on the 674 * arrival interface. 675 */ 676 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 677 if (inm == NULL) { 678 ipstat.ips_cantforward++; 679 m_freem(m); 680 return; 681 } 682 goto ours; 683 } 684 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 685 in_nullhost(ip->ip_dst)) 686 goto ours; 687 688 /* 689 * Not for us; forward if possible and desirable. 690 */ 691 if (ipforwarding == 0) { 692 ipstat.ips_cantforward++; 693 m_freem(m); 694 } else { 695 /* 696 * If ip_dst matched any of my address on !IFF_UP interface, 697 * and there's no IFF_UP interface that matches ip_dst, 698 * send icmp unreach. Forwarding it will result in in-kernel 699 * forwarding loop till TTL goes to 0. 700 */ 701 if (downmatch) { 702 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 703 ipstat.ips_cantforward++; 704 return; 705 } 706#ifdef IPSEC 707 if (ipsec4_in_reject(m, NULL)) { 708 ipsecstat.in_polvio++; 709 goto bad; 710 } 711#endif 712 713 ip_forward(m, 0); 714 } 715 return; 716 717ours: 718 /* 719 * If offset or IP_MF are set, must reassemble. 720 * Otherwise, nothing need be done. 721 * (We could look in the reassembly queue to see 722 * if the packet was previously fragmented, 723 * but it's not worth the time; just let them time out.) 724 */ 725 if (ip->ip_off & ~(IP_DF|IP_RF)) { 726 /* 727 * Look for queue of fragments 728 * of this datagram. 729 */ 730 IPQ_LOCK(); 731 LIST_FOREACH(fp, &ipq, ipq_q) 732 if (ip->ip_id == fp->ipq_id && 733 in_hosteq(ip->ip_src, fp->ipq_src) && 734 in_hosteq(ip->ip_dst, fp->ipq_dst) && 735 ip->ip_p == fp->ipq_p) 736 goto found; 737 fp = 0; 738found: 739 740 /* 741 * Adjust ip_len to not reflect header, 742 * set ipqe_mff if more fragments are expected, 743 * convert offset of this to bytes. 744 */ 745 ip->ip_len -= hlen; 746 mff = (ip->ip_off & IP_MF) != 0; 747 if (mff) { 748 /* 749 * Make sure that fragments have a data length 750 * that's a non-zero multiple of 8 bytes. 751 */ 752 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 753 ipstat.ips_badfrags++; 754 IPQ_UNLOCK(); 755 goto bad; 756 } 757 } 758 ip->ip_off <<= 3; 759 760 /* 761 * If datagram marked as having more fragments 762 * or if this is not the first fragment, 763 * attempt reassembly; if it succeeds, proceed. 764 */ 765 if (mff || ip->ip_off) { 766 ipstat.ips_fragments++; 767 ipqe = pool_get(&ipqent_pool, PR_NOWAIT); 768 if (ipqe == NULL) { 769 ipstat.ips_rcvmemdrop++; 770 IPQ_UNLOCK(); 771 goto bad; 772 } 773 ipqe->ipqe_mff = mff; 774 ipqe->ipqe_m = m; 775 ipqe->ipqe_ip = ip; 776 m = ip_reass(ipqe, fp); 777 if (m == 0) { 778 IPQ_UNLOCK(); 779 return; 780 } 781 ipstat.ips_reassembled++; 782 ip = mtod(m, struct ip *); 783 hlen = ip->ip_hl << 2; 784 ip->ip_len += hlen; 785 } else 786 if (fp) 787 ip_freef(fp); 788 IPQ_UNLOCK(); 789 } 790 791#ifdef IPSEC 792 /* 793 * enforce IPsec policy checking if we are seeing last header. 794 * note that we do not visit this with protocols with pcb layer 795 * code - like udp/tcp/raw ip. 796 */ 797 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 798 ipsec4_in_reject(m, NULL)) { 799 ipsecstat.in_polvio++; 800 goto bad; 801 } 802#endif 803 804 /* 805 * Switch out to protocol's input routine. 806 */ 807#if IFA_STATS 808 if (ia && ip) 809 ia->ia_ifa.ifa_data.ifad_inbytes += ip->ip_len; 810#endif 811 ipstat.ips_delivered++; 812 { 813 int off = hlen, nh = ip->ip_p; 814 815 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 816 return; 817 } 818bad: 819 m_freem(m); 820 return; 821 822badcsum: 823 ipstat.ips_badsum++; 824 m_freem(m); 825} 826 827/* 828 * Take incoming datagram fragment and try to 829 * reassemble it into whole datagram. If a chain for 830 * reassembly of this datagram already exists, then it 831 * is given as fp; otherwise have to make a chain. 832 */ 833struct mbuf * 834ip_reass(ipqe, fp) 835 struct ipqent *ipqe; 836 struct ipq *fp; 837{ 838 struct mbuf *m = ipqe->ipqe_m; 839 struct ipqent *nq, *p, *q; 840 struct ip *ip; 841 struct mbuf *t; 842 int hlen = ipqe->ipqe_ip->ip_hl << 2; 843 int i, next; 844 845 IPQ_LOCK_CHECK(); 846 847 /* 848 * Presence of header sizes in mbufs 849 * would confuse code below. 850 */ 851 m->m_data += hlen; 852 m->m_len -= hlen; 853 854 /* 855 * If first fragment to arrive, create a reassembly queue. 856 */ 857 if (fp == 0) { 858 /* 859 * Enforce upper bound on number of fragmented packets 860 * for which we attempt reassembly; 861 * If maxfrag is 0, never accept fragments. 862 * If maxfrag is -1, accept all fragments without limitation. 863 */ 864 if (ip_maxfragpackets < 0) 865 ; 866 else if (ip_nfragpackets >= ip_maxfragpackets) 867 goto dropfrag; 868 ip_nfragpackets++; 869 MALLOC(fp, struct ipq *, sizeof (struct ipq), 870 M_FTABLE, M_NOWAIT); 871 if (fp == NULL) 872 goto dropfrag; 873 LIST_INSERT_HEAD(&ipq, fp, ipq_q); 874 fp->ipq_ttl = IPFRAGTTL; 875 fp->ipq_p = ipqe->ipqe_ip->ip_p; 876 fp->ipq_id = ipqe->ipqe_ip->ip_id; 877 TAILQ_INIT(&fp->ipq_fragq); 878 fp->ipq_src = ipqe->ipqe_ip->ip_src; 879 fp->ipq_dst = ipqe->ipqe_ip->ip_dst; 880 p = NULL; 881 goto insert; 882 } 883 884 /* 885 * Find a segment which begins after this one does. 886 */ 887 for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; 888 p = q, q = TAILQ_NEXT(q, ipqe_q)) 889 if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off) 890 break; 891 892 /* 893 * If there is a preceding segment, it may provide some of 894 * our data already. If so, drop the data from the incoming 895 * segment. If it provides all of our data, drop us. 896 */ 897 if (p != NULL) { 898 i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len - 899 ipqe->ipqe_ip->ip_off; 900 if (i > 0) { 901 if (i >= ipqe->ipqe_ip->ip_len) 902 goto dropfrag; 903 m_adj(ipqe->ipqe_m, i); 904 ipqe->ipqe_ip->ip_off += i; 905 ipqe->ipqe_ip->ip_len -= i; 906 } 907 } 908 909 /* 910 * While we overlap succeeding segments trim them or, 911 * if they are completely covered, dequeue them. 912 */ 913 for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len > 914 q->ipqe_ip->ip_off; q = nq) { 915 i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) - 916 q->ipqe_ip->ip_off; 917 if (i < q->ipqe_ip->ip_len) { 918 q->ipqe_ip->ip_len -= i; 919 q->ipqe_ip->ip_off += i; 920 m_adj(q->ipqe_m, i); 921 break; 922 } 923 nq = TAILQ_NEXT(q, ipqe_q); 924 m_freem(q->ipqe_m); 925 TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q); 926 pool_put(&ipqent_pool, q); 927 } 928 929insert: 930 /* 931 * Stick new segment in its place; 932 * check for complete reassembly. 933 */ 934 if (p == NULL) { 935 TAILQ_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); 936 } else { 937 TAILQ_INSERT_AFTER(&fp->ipq_fragq, p, ipqe, ipqe_q); 938 } 939 next = 0; 940 for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; 941 p = q, q = TAILQ_NEXT(q, ipqe_q)) { 942 if (q->ipqe_ip->ip_off != next) 943 return (0); 944 next += q->ipqe_ip->ip_len; 945 } 946 if (p->ipqe_mff) 947 return (0); 948 949 /* 950 * Reassembly is complete. Check for a bogus message size and 951 * concatenate fragments. 952 */ 953 q = TAILQ_FIRST(&fp->ipq_fragq); 954 ip = q->ipqe_ip; 955 if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) { 956 ipstat.ips_toolong++; 957 ip_freef(fp); 958 return (0); 959 } 960 m = q->ipqe_m; 961 t = m->m_next; 962 m->m_next = 0; 963 m_cat(m, t); 964 nq = TAILQ_NEXT(q, ipqe_q); 965 pool_put(&ipqent_pool, q); 966 for (q = nq; q != NULL; q = nq) { 967 t = q->ipqe_m; 968 nq = TAILQ_NEXT(q, ipqe_q); 969 pool_put(&ipqent_pool, q); 970 m_cat(m, t); 971 } 972 973 /* 974 * Create header for new ip packet by 975 * modifying header of first packet; 976 * dequeue and discard fragment reassembly header. 977 * Make header visible. 978 */ 979 ip->ip_len = next; 980 ip->ip_src = fp->ipq_src; 981 ip->ip_dst = fp->ipq_dst; 982 LIST_REMOVE(fp, ipq_q); 983 FREE(fp, M_FTABLE); 984 ip_nfragpackets--; 985 m->m_len += (ip->ip_hl << 2); 986 m->m_data -= (ip->ip_hl << 2); 987 /* some debugging cruft by sklower, below, will go away soon */ 988 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 989 int plen = 0; 990 for (t = m; t; t = t->m_next) 991 plen += t->m_len; 992 m->m_pkthdr.len = plen; 993 } 994 return (m); 995 996dropfrag: 997 ipstat.ips_fragdropped++; 998 m_freem(m); 999 pool_put(&ipqent_pool, ipqe); 1000 return (0); 1001} 1002 1003/* 1004 * Free a fragment reassembly header and all 1005 * associated datagrams. 1006 */ 1007void 1008ip_freef(fp) 1009 struct ipq *fp; 1010{ 1011 struct ipqent *q, *p; 1012 1013 IPQ_LOCK_CHECK(); 1014 1015 for (q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; q = p) { 1016 p = TAILQ_NEXT(q, ipqe_q); 1017 m_freem(q->ipqe_m); 1018 TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q); 1019 pool_put(&ipqent_pool, q); 1020 } 1021 LIST_REMOVE(fp, ipq_q); 1022 FREE(fp, M_FTABLE); 1023 ip_nfragpackets--; 1024} 1025 1026/* 1027 * IP timer processing; 1028 * if a timer expires on a reassembly 1029 * queue, discard it. 1030 */ 1031void 1032ip_slowtimo() 1033{ 1034 struct ipq *fp, *nfp; 1035 int s = splsoftnet(); 1036 1037 IPQ_LOCK(); 1038 for (fp = LIST_FIRST(&ipq); fp != NULL; fp = nfp) { 1039 nfp = LIST_NEXT(fp, ipq_q); 1040 if (--fp->ipq_ttl == 0) { 1041 ipstat.ips_fragtimeout++; 1042 ip_freef(fp); 1043 } 1044 } 1045 /* 1046 * If we are over the maximum number of fragments 1047 * (due to the limit being lowered), drain off 1048 * enough to get down to the new limit. 1049 */ 1050 if (ip_maxfragpackets < 0) 1051 ; 1052 else { 1053 while (ip_nfragpackets > ip_maxfragpackets && LIST_FIRST(&ipq)) 1054 ip_freef(LIST_FIRST(&ipq)); 1055 } 1056 IPQ_UNLOCK(); 1057#ifdef GATEWAY 1058 ipflow_slowtimo(); 1059#endif 1060 splx(s); 1061} 1062 1063/* 1064 * Drain off all datagram fragments. 1065 */ 1066void 1067ip_drain() 1068{ 1069 1070 /* 1071 * We may be called from a device's interrupt context. If 1072 * the ipq is already busy, just bail out now. 1073 */ 1074 if (ipq_lock_try() == 0) 1075 return; 1076 1077 while (LIST_FIRST(&ipq) != NULL) { 1078 ipstat.ips_fragdropped++; 1079 ip_freef(LIST_FIRST(&ipq)); 1080 } 1081 1082 IPQ_UNLOCK(); 1083} 1084 1085/* 1086 * Do option processing on a datagram, 1087 * possibly discarding it if bad options are encountered, 1088 * or forwarding it if source-routed. 1089 * Returns 1 if packet has been forwarded/freed, 1090 * 0 if the packet should be processed further. 1091 */ 1092int 1093ip_dooptions(m) 1094 struct mbuf *m; 1095{ 1096 struct ip *ip = mtod(m, struct ip *); 1097 u_char *cp, *cp0; 1098 struct ip_timestamp *ipt; 1099 struct in_ifaddr *ia; 1100 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1101 struct in_addr dst; 1102 n_time ntime; 1103 1104 dst = ip->ip_dst; 1105 cp = (u_char *)(ip + 1); 1106 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1107 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1108 opt = cp[IPOPT_OPTVAL]; 1109 if (opt == IPOPT_EOL) 1110 break; 1111 if (opt == IPOPT_NOP) 1112 optlen = 1; 1113 else { 1114 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1115 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1116 goto bad; 1117 } 1118 optlen = cp[IPOPT_OLEN]; 1119 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1120 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1121 goto bad; 1122 } 1123 } 1124 switch (opt) { 1125 1126 default: 1127 break; 1128 1129 /* 1130 * Source routing with record. 1131 * Find interface with current destination address. 1132 * If none on this machine then drop if strictly routed, 1133 * or do nothing if loosely routed. 1134 * Record interface address and bring up next address 1135 * component. If strictly routed make sure next 1136 * address is on directly accessible net. 1137 */ 1138 case IPOPT_LSRR: 1139 case IPOPT_SSRR: 1140 if (ip_allowsrcrt == 0) { 1141 type = ICMP_UNREACH; 1142 code = ICMP_UNREACH_NET_PROHIB; 1143 goto bad; 1144 } 1145 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1146 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1147 goto bad; 1148 } 1149 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1150 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1151 goto bad; 1152 } 1153 ipaddr.sin_addr = ip->ip_dst; 1154 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); 1155 if (ia == 0) { 1156 if (opt == IPOPT_SSRR) { 1157 type = ICMP_UNREACH; 1158 code = ICMP_UNREACH_SRCFAIL; 1159 goto bad; 1160 } 1161 /* 1162 * Loose routing, and not at next destination 1163 * yet; nothing to do except forward. 1164 */ 1165 break; 1166 } 1167 off--; /* 0 origin */ 1168 if ((off + sizeof(struct in_addr)) > optlen) { 1169 /* 1170 * End of source route. Should be for us. 1171 */ 1172 save_rte(cp, ip->ip_src); 1173 break; 1174 } 1175 /* 1176 * locate outgoing interface 1177 */ 1178 bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr, 1179 sizeof(ipaddr.sin_addr)); 1180 if (opt == IPOPT_SSRR) 1181 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); 1182 else 1183 ia = ip_rtaddr(ipaddr.sin_addr); 1184 if (ia == 0) { 1185 type = ICMP_UNREACH; 1186 code = ICMP_UNREACH_SRCFAIL; 1187 goto bad; 1188 } 1189 ip->ip_dst = ipaddr.sin_addr; 1190 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1191 (caddr_t)(cp + off), sizeof(struct in_addr)); 1192 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1193 /* 1194 * Let ip_intr's mcast routing check handle mcast pkts 1195 */ 1196 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1197 break; 1198 1199 case IPOPT_RR: 1200 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1201 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1202 goto bad; 1203 } 1204 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1205 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1206 goto bad; 1207 } 1208 /* 1209 * If no space remains, ignore. 1210 */ 1211 off--; /* 0 origin */ 1212 if ((off + sizeof(struct in_addr)) > optlen) 1213 break; 1214 bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr, 1215 sizeof(ipaddr.sin_addr)); 1216 /* 1217 * locate outgoing interface; if we're the destination, 1218 * use the incoming interface (should be same). 1219 */ 1220 if ((ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)))) 1221 == NULL && 1222 (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) { 1223 type = ICMP_UNREACH; 1224 code = ICMP_UNREACH_HOST; 1225 goto bad; 1226 } 1227 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1228 (caddr_t)(cp + off), sizeof(struct in_addr)); 1229 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1230 break; 1231 1232 case IPOPT_TS: 1233 code = cp - (u_char *)ip; 1234 ipt = (struct ip_timestamp *)cp; 1235 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1236 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1237 goto bad; 1238 } 1239 if (ipt->ipt_ptr < 5) { 1240 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1241 goto bad; 1242 } 1243 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) { 1244 if (++ipt->ipt_oflw == 0) { 1245 code = (u_char *)&ipt->ipt_ptr - 1246 (u_char *)ip; 1247 goto bad; 1248 } 1249 break; 1250 } 1251 cp0 = (cp + ipt->ipt_ptr - 1); 1252 switch (ipt->ipt_flg) { 1253 1254 case IPOPT_TS_TSONLY: 1255 break; 1256 1257 case IPOPT_TS_TSANDADDR: 1258 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1259 sizeof(struct in_addr) > ipt->ipt_len) { 1260 code = (u_char *)&ipt->ipt_ptr - 1261 (u_char *)ip; 1262 goto bad; 1263 } 1264 ipaddr.sin_addr = dst; 1265 ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr), 1266 m->m_pkthdr.rcvif)); 1267 if (ia == 0) 1268 continue; 1269 bcopy(&ia->ia_addr.sin_addr, 1270 cp0, sizeof(struct in_addr)); 1271 ipt->ipt_ptr += sizeof(struct in_addr); 1272 break; 1273 1274 case IPOPT_TS_PRESPEC: 1275 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1276 sizeof(struct in_addr) > ipt->ipt_len) { 1277 code = (u_char *)&ipt->ipt_ptr - 1278 (u_char *)ip; 1279 goto bad; 1280 } 1281 bcopy(cp0, &ipaddr.sin_addr, 1282 sizeof(struct in_addr)); 1283 if (ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))) 1284 == NULL) 1285 continue; 1286 ipt->ipt_ptr += sizeof(struct in_addr); 1287 break; 1288 1289 default: 1290 /* XXX can't take &ipt->ipt_flg */ 1291 code = (u_char *)&ipt->ipt_ptr - 1292 (u_char *)ip + 1; 1293 goto bad; 1294 } 1295 ntime = iptime(); 1296 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1297 bcopy(cp0, (caddr_t)cp + ipt->ipt_ptr - 1, 1298 sizeof(n_time)); 1299 ipt->ipt_ptr += sizeof(n_time); 1300 } 1301 } 1302 if (forward) { 1303 if (ip_forwsrcrt == 0) { 1304 type = ICMP_UNREACH; 1305 code = ICMP_UNREACH_SRCFAIL; 1306 goto bad; 1307 } 1308 ip_forward(m, 1); 1309 return (1); 1310 } 1311 return (0); 1312bad: 1313 icmp_error(m, type, code, 0, 0); 1314 ipstat.ips_badoptions++; 1315 return (1); 1316} 1317 1318/* 1319 * Given address of next destination (final or next hop), 1320 * return internet address info of interface to be used to get there. 1321 */ 1322struct in_ifaddr * 1323ip_rtaddr(dst) 1324 struct in_addr dst; 1325{ 1326 struct sockaddr_in *sin; 1327 1328 sin = satosin(&ipforward_rt.ro_dst); 1329 1330 if (ipforward_rt.ro_rt == 0 || !in_hosteq(dst, sin->sin_addr)) { 1331 if (ipforward_rt.ro_rt) { 1332 RTFREE(ipforward_rt.ro_rt); 1333 ipforward_rt.ro_rt = 0; 1334 } 1335 sin->sin_family = AF_INET; 1336 sin->sin_len = sizeof(*sin); 1337 sin->sin_addr = dst; 1338 1339 rtalloc(&ipforward_rt); 1340 } 1341 if (ipforward_rt.ro_rt == 0) 1342 return ((struct in_ifaddr *)0); 1343 return (ifatoia(ipforward_rt.ro_rt->rt_ifa)); 1344} 1345 1346/* 1347 * Save incoming source route for use in replies, 1348 * to be picked up later by ip_srcroute if the receiver is interested. 1349 */ 1350void 1351save_rte(option, dst) 1352 u_char *option; 1353 struct in_addr dst; 1354{ 1355 unsigned olen; 1356 1357 olen = option[IPOPT_OLEN]; 1358#ifdef DIAGNOSTIC 1359 if (ipprintfs) 1360 printf("save_rte: olen %d\n", olen); 1361#endif /* 0 */ 1362 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1363 return; 1364 bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen); 1365 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1366 ip_srcrt.dst = dst; 1367} 1368 1369/* 1370 * Retrieve incoming source route for use in replies, 1371 * in the same form used by setsockopt. 1372 * The first hop is placed before the options, will be removed later. 1373 */ 1374struct mbuf * 1375ip_srcroute() 1376{ 1377 struct in_addr *p, *q; 1378 struct mbuf *m; 1379 1380 if (ip_nhops == 0) 1381 return ((struct mbuf *)0); 1382 m = m_get(M_DONTWAIT, MT_SOOPTS); 1383 if (m == 0) 1384 return ((struct mbuf *)0); 1385 1386#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1387 1388 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1389 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1390 OPTSIZ; 1391#ifdef DIAGNOSTIC 1392 if (ipprintfs) 1393 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1394#endif 1395 1396 /* 1397 * First save first hop for return route 1398 */ 1399 p = &ip_srcrt.route[ip_nhops - 1]; 1400 *(mtod(m, struct in_addr *)) = *p--; 1401#ifdef DIAGNOSTIC 1402 if (ipprintfs) 1403 printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1404#endif 1405 1406 /* 1407 * Copy option fields and padding (nop) to mbuf. 1408 */ 1409 ip_srcrt.nop = IPOPT_NOP; 1410 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1411 bcopy((caddr_t)&ip_srcrt.nop, 1412 mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ); 1413 q = (struct in_addr *)(mtod(m, caddr_t) + 1414 sizeof(struct in_addr) + OPTSIZ); 1415#undef OPTSIZ 1416 /* 1417 * Record return path as an IP source route, 1418 * reversing the path (pointers are now aligned). 1419 */ 1420 while (p >= ip_srcrt.route) { 1421#ifdef DIAGNOSTIC 1422 if (ipprintfs) 1423 printf(" %x", ntohl(q->s_addr)); 1424#endif 1425 *q++ = *p--; 1426 } 1427 /* 1428 * Last hop goes to final destination. 1429 */ 1430 *q = ip_srcrt.dst; 1431#ifdef DIAGNOSTIC 1432 if (ipprintfs) 1433 printf(" %x\n", ntohl(q->s_addr)); 1434#endif 1435 return (m); 1436} 1437 1438/* 1439 * Strip out IP options, at higher 1440 * level protocol in the kernel. 1441 * Second argument is buffer to which options 1442 * will be moved, and return value is their length. 1443 * XXX should be deleted; last arg currently ignored. 1444 */ 1445void 1446ip_stripoptions(m, mopt) 1447 struct mbuf *m; 1448 struct mbuf *mopt; 1449{ 1450 int i; 1451 struct ip *ip = mtod(m, struct ip *); 1452 caddr_t opts; 1453 int olen; 1454 1455 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1456 opts = (caddr_t)(ip + 1); 1457 i = m->m_len - (sizeof (struct ip) + olen); 1458 bcopy(opts + olen, opts, (unsigned)i); 1459 m->m_len -= olen; 1460 if (m->m_flags & M_PKTHDR) 1461 m->m_pkthdr.len -= olen; 1462 ip->ip_len -= olen; 1463 ip->ip_hl = sizeof (struct ip) >> 2; 1464} 1465 1466const int inetctlerrmap[PRC_NCMDS] = { 1467 0, 0, 0, 0, 1468 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1469 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1470 EMSGSIZE, EHOSTUNREACH, 0, 0, 1471 0, 0, 0, 0, 1472 ENOPROTOOPT 1473}; 1474 1475/* 1476 * Forward a packet. If some error occurs return the sender 1477 * an icmp packet. Note we can't always generate a meaningful 1478 * icmp message because icmp doesn't have a large enough repertoire 1479 * of codes and types. 1480 * 1481 * If not forwarding, just drop the packet. This could be confusing 1482 * if ipforwarding was zero but some routing protocol was advancing 1483 * us as a gateway to somewhere. However, we must let the routing 1484 * protocol deal with that. 1485 * 1486 * The srcrt parameter indicates whether the packet is being forwarded 1487 * via a source route. 1488 */ 1489void 1490ip_forward(m, srcrt) 1491 struct mbuf *m; 1492 int srcrt; 1493{ 1494 struct ip *ip = mtod(m, struct ip *); 1495 struct sockaddr_in *sin; 1496 struct rtentry *rt; 1497 int error, type = 0, code = 0; 1498 struct mbuf *mcopy; 1499 n_long dest; 1500 struct ifnet *destifp; 1501#ifdef IPSEC 1502 struct ifnet dummyifp; 1503#endif 1504 1505 /* 1506 * Clear any in-bound checksum flags for this packet. 1507 */ 1508 m->m_pkthdr.csum_flags = 0; 1509 1510 dest = 0; 1511#ifdef DIAGNOSTIC 1512 if (ipprintfs) 1513 printf("forward: src %2.2x dst %2.2x ttl %x\n", 1514 ntohl(ip->ip_src.s_addr), 1515 ntohl(ip->ip_dst.s_addr), ip->ip_ttl); 1516#endif 1517 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1518 ipstat.ips_cantforward++; 1519 m_freem(m); 1520 return; 1521 } 1522 if (ip->ip_ttl <= IPTTLDEC) { 1523 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1524 return; 1525 } 1526 ip->ip_ttl -= IPTTLDEC; 1527 1528 sin = satosin(&ipforward_rt.ro_dst); 1529 if ((rt = ipforward_rt.ro_rt) == 0 || 1530 !in_hosteq(ip->ip_dst, sin->sin_addr)) { 1531 if (ipforward_rt.ro_rt) { 1532 RTFREE(ipforward_rt.ro_rt); 1533 ipforward_rt.ro_rt = 0; 1534 } 1535 sin->sin_family = AF_INET; 1536 sin->sin_len = sizeof(struct sockaddr_in); 1537 sin->sin_addr = ip->ip_dst; 1538 1539 rtalloc(&ipforward_rt); 1540 if (ipforward_rt.ro_rt == 0) { 1541 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1542 return; 1543 } 1544 rt = ipforward_rt.ro_rt; 1545 } 1546 1547 /* 1548 * Save at most 68 bytes of the packet in case 1549 * we need to generate an ICMP message to the src. 1550 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1551 */ 1552 mcopy = m_copym(m, 0, imin((int)ip->ip_len, 68), M_DONTWAIT); 1553 if (mcopy) 1554 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1555 1556 /* 1557 * If forwarding packet using same interface that it came in on, 1558 * perhaps should send a redirect to sender to shortcut a hop. 1559 * Only send redirect if source is sending directly to us, 1560 * and if packet was not source routed (or has any options). 1561 * Also, don't send redirect if forwarding using a default route 1562 * or a route modified by a redirect. 1563 */ 1564 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1565 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1566 !in_nullhost(satosin(rt_key(rt))->sin_addr) && 1567 ipsendredirects && !srcrt) { 1568 if (rt->rt_ifa && 1569 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1570 ifatoia(rt->rt_ifa)->ia_subnet) { 1571 if (rt->rt_flags & RTF_GATEWAY) 1572 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1573 else 1574 dest = ip->ip_dst.s_addr; 1575 /* 1576 * Router requirements says to only send host 1577 * redirects. 1578 */ 1579 type = ICMP_REDIRECT; 1580 code = ICMP_REDIRECT_HOST; 1581#ifdef DIAGNOSTIC 1582 if (ipprintfs) 1583 printf("redirect (%d) to %x\n", code, 1584 (u_int32_t)dest); 1585#endif 1586 } 1587 } 1588 1589#ifdef IPSEC 1590 /* Don't lookup socket in forwarding case */ 1591 (void)ipsec_setsocket(m, NULL); 1592#endif 1593 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1594 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 0); 1595 if (error) 1596 ipstat.ips_cantforward++; 1597 else { 1598 ipstat.ips_forward++; 1599 if (type) 1600 ipstat.ips_redirectsent++; 1601 else { 1602 if (mcopy) { 1603#ifdef GATEWAY 1604 if (mcopy->m_flags & M_CANFASTFWD) 1605 ipflow_create(&ipforward_rt, mcopy); 1606#endif 1607 m_freem(mcopy); 1608 } 1609 return; 1610 } 1611 } 1612 if (mcopy == NULL) 1613 return; 1614 destifp = NULL; 1615 1616 switch (error) { 1617 1618 case 0: /* forwarded, but need redirect */ 1619 /* type, code set above */ 1620 break; 1621 1622 case ENETUNREACH: /* shouldn't happen, checked above */ 1623 case EHOSTUNREACH: 1624 case ENETDOWN: 1625 case EHOSTDOWN: 1626 default: 1627 type = ICMP_UNREACH; 1628 code = ICMP_UNREACH_HOST; 1629 break; 1630 1631 case EMSGSIZE: 1632 type = ICMP_UNREACH; 1633 code = ICMP_UNREACH_NEEDFRAG; 1634#ifndef IPSEC 1635 if (ipforward_rt.ro_rt) 1636 destifp = ipforward_rt.ro_rt->rt_ifp; 1637#else 1638 /* 1639 * If the packet is routed over IPsec tunnel, tell the 1640 * originator the tunnel MTU. 1641 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1642 * XXX quickhack!!! 1643 */ 1644 if (ipforward_rt.ro_rt) { 1645 struct secpolicy *sp; 1646 int ipsecerror; 1647 size_t ipsechdr; 1648 struct route *ro; 1649 1650 sp = ipsec4_getpolicybyaddr(mcopy, 1651 IPSEC_DIR_OUTBOUND, 1652 IP_FORWARDING, 1653 &ipsecerror); 1654 1655 if (sp == NULL) 1656 destifp = ipforward_rt.ro_rt->rt_ifp; 1657 else { 1658 /* count IPsec header size */ 1659 ipsechdr = ipsec4_hdrsiz(mcopy, 1660 IPSEC_DIR_OUTBOUND, 1661 NULL); 1662 1663 /* 1664 * find the correct route for outer IPv4 1665 * header, compute tunnel MTU. 1666 * 1667 * XXX BUG ALERT 1668 * The "dummyifp" code relies upon the fact 1669 * that icmp_error() touches only ifp->if_mtu. 1670 */ 1671 /*XXX*/ 1672 destifp = NULL; 1673 if (sp->req != NULL 1674 && sp->req->sav != NULL 1675 && sp->req->sav->sah != NULL) { 1676 ro = &sp->req->sav->sah->sa_route; 1677 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1678 dummyifp.if_mtu = 1679 ro->ro_rt->rt_rmx.rmx_mtu ? 1680 ro->ro_rt->rt_rmx.rmx_mtu : 1681 ro->ro_rt->rt_ifp->if_mtu; 1682 dummyifp.if_mtu -= ipsechdr; 1683 destifp = &dummyifp; 1684 } 1685 } 1686 1687 key_freesp(sp); 1688 } 1689 } 1690#endif /*IPSEC*/ 1691 ipstat.ips_cantfrag++; 1692 break; 1693 1694 case ENOBUFS: 1695#if 1 1696 /* 1697 * a router should not generate ICMP_SOURCEQUENCH as 1698 * required in RFC1812 Requirements for IP Version 4 Routers. 1699 * source quench could be a big problem under DoS attacks, 1700 * or if the underlying interface is rate-limited. 1701 */ 1702 if (mcopy) 1703 m_freem(mcopy); 1704 return; 1705#else 1706 type = ICMP_SOURCEQUENCH; 1707 code = 0; 1708 break; 1709#endif 1710 } 1711 icmp_error(mcopy, type, code, dest, destifp); 1712} 1713 1714void 1715ip_savecontrol(inp, mp, ip, m) 1716 struct inpcb *inp; 1717 struct mbuf **mp; 1718 struct ip *ip; 1719 struct mbuf *m; 1720{ 1721 1722 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1723 struct timeval tv; 1724 1725 microtime(&tv); 1726 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1727 SCM_TIMESTAMP, SOL_SOCKET); 1728 if (*mp) 1729 mp = &(*mp)->m_next; 1730 } 1731 if (inp->inp_flags & INP_RECVDSTADDR) { 1732 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1733 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1734 if (*mp) 1735 mp = &(*mp)->m_next; 1736 } 1737#ifdef notyet 1738 /* 1739 * XXX 1740 * Moving these out of udp_input() made them even more broken 1741 * than they already were. 1742 * - fenner@parc.xerox.com 1743 */ 1744 /* options were tossed already */ 1745 if (inp->inp_flags & INP_RECVOPTS) { 1746 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1747 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1748 if (*mp) 1749 mp = &(*mp)->m_next; 1750 } 1751 /* ip_srcroute doesn't do what we want here, need to fix */ 1752 if (inp->inp_flags & INP_RECVRETOPTS) { 1753 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1754 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1755 if (*mp) 1756 mp = &(*mp)->m_next; 1757 } 1758#endif 1759 if (inp->inp_flags & INP_RECVIF) { 1760 struct sockaddr_dl sdl; 1761 1762 sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]); 1763 sdl.sdl_family = AF_LINK; 1764 sdl.sdl_index = m->m_pkthdr.rcvif ? 1765 m->m_pkthdr.rcvif->if_index : 0; 1766 sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0; 1767 *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len, 1768 IP_RECVIF, IPPROTO_IP); 1769 if (*mp) 1770 mp = &(*mp)->m_next; 1771 } 1772} 1773 1774int 1775ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 1776 int *name; 1777 u_int namelen; 1778 void *oldp; 1779 size_t *oldlenp; 1780 void *newp; 1781 size_t newlen; 1782{ 1783 extern int subnetsarelocal, hostzeroisbroadcast; 1784 1785 int error, old; 1786 1787 /* All sysctl names at this level are terminal. */ 1788 if (namelen != 1) 1789 return (ENOTDIR); 1790 1791 switch (name[0]) { 1792 case IPCTL_FORWARDING: 1793 return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding)); 1794 case IPCTL_SENDREDIRECTS: 1795 return (sysctl_int(oldp, oldlenp, newp, newlen, 1796 &ipsendredirects)); 1797 case IPCTL_DEFTTL: 1798 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl)); 1799#ifdef notyet 1800 case IPCTL_DEFMTU: 1801 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu)); 1802#endif 1803 case IPCTL_FORWSRCRT: 1804 /* Don't allow this to change in a secure environment. */ 1805 if (securelevel > 0) 1806 return (sysctl_rdint(oldp, oldlenp, newp, 1807 ip_forwsrcrt)); 1808 else 1809 return (sysctl_int(oldp, oldlenp, newp, newlen, 1810 &ip_forwsrcrt)); 1811 case IPCTL_DIRECTEDBCAST: 1812 return (sysctl_int(oldp, oldlenp, newp, newlen, 1813 &ip_directedbcast)); 1814 case IPCTL_ALLOWSRCRT: 1815 return (sysctl_int(oldp, oldlenp, newp, newlen, 1816 &ip_allowsrcrt)); 1817 case IPCTL_SUBNETSARELOCAL: 1818 return (sysctl_int(oldp, oldlenp, newp, newlen, 1819 &subnetsarelocal)); 1820 case IPCTL_MTUDISC: 1821 error = sysctl_int(oldp, oldlenp, newp, newlen, 1822 &ip_mtudisc); 1823 if (ip_mtudisc != 0 && ip_mtudisc_timeout_q == NULL) { 1824 ip_mtudisc_timeout_q = 1825 rt_timer_queue_create(ip_mtudisc_timeout); 1826 } else if (ip_mtudisc == 0 && ip_mtudisc_timeout_q != NULL) { 1827 rt_timer_queue_destroy(ip_mtudisc_timeout_q, TRUE); 1828 ip_mtudisc_timeout_q = NULL; 1829 } 1830 return error; 1831 case IPCTL_ANONPORTMIN: 1832 old = anonportmin; 1833 error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmin); 1834 if (anonportmin >= anonportmax || anonportmin < 0 1835 || anonportmin > 65535 1836#ifndef IPNOPRIVPORTS 1837 || anonportmin < IPPORT_RESERVED 1838#endif 1839 ) { 1840 anonportmin = old; 1841 return (EINVAL); 1842 } 1843 return (error); 1844 case IPCTL_ANONPORTMAX: 1845 old = anonportmax; 1846 error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmax); 1847 if (anonportmin >= anonportmax || anonportmax < 0 1848 || anonportmax > 65535 1849#ifndef IPNOPRIVPORTS 1850 || anonportmax < IPPORT_RESERVED 1851#endif 1852 ) { 1853 anonportmax = old; 1854 return (EINVAL); 1855 } 1856 return (error); 1857 case IPCTL_MTUDISCTIMEOUT: 1858 error = sysctl_int(oldp, oldlenp, newp, newlen, 1859 &ip_mtudisc_timeout); 1860 if (ip_mtudisc_timeout_q != NULL) 1861 rt_timer_queue_change(ip_mtudisc_timeout_q, 1862 ip_mtudisc_timeout); 1863 return (error); 1864#ifdef GATEWAY 1865 case IPCTL_MAXFLOWS: 1866 { 1867 int s; 1868 1869 error = sysctl_int(oldp, oldlenp, newp, newlen, 1870 &ip_maxflows); 1871 s = splsoftnet(); 1872 ipflow_reap(0); 1873 splx(s); 1874 return (error); 1875 } 1876#endif 1877 case IPCTL_HOSTZEROBROADCAST: 1878 return (sysctl_int(oldp, oldlenp, newp, newlen, 1879 &hostzeroisbroadcast)); 1880#if NGIF > 0 1881 case IPCTL_GIF_TTL: 1882 return(sysctl_int(oldp, oldlenp, newp, newlen, 1883 &ip_gif_ttl)); 1884#endif 1885 1886#if NGRE > 0 1887 case IPCTL_GRE_TTL: 1888 return(sysctl_int(oldp, oldlenp, newp, newlen, 1889 &ip_gre_ttl)); 1890#endif 1891 1892#ifndef IPNOPRIVPORTS 1893 case IPCTL_LOWPORTMIN: 1894 old = lowportmin; 1895 error = sysctl_int(oldp, oldlenp, newp, newlen, &lowportmin); 1896 if (lowportmin >= lowportmax 1897 || lowportmin > IPPORT_RESERVEDMAX 1898 || lowportmin < IPPORT_RESERVEDMIN 1899 ) { 1900 lowportmin = old; 1901 return (EINVAL); 1902 } 1903 return (error); 1904 case IPCTL_LOWPORTMAX: 1905 old = lowportmax; 1906 error = sysctl_int(oldp, oldlenp, newp, newlen, &lowportmax); 1907 if (lowportmin >= lowportmax 1908 || lowportmax > IPPORT_RESERVEDMAX 1909 || lowportmax < IPPORT_RESERVEDMIN 1910 ) { 1911 lowportmax = old; 1912 return (EINVAL); 1913 } 1914 return (error); 1915#endif 1916 1917 case IPCTL_MAXFRAGPACKETS: 1918 return (sysctl_int(oldp, oldlenp, newp, newlen, 1919 &ip_maxfragpackets)); 1920 1921 default: 1922 return (EOPNOTSUPP); 1923 } 1924 /* NOTREACHED */ 1925} 1926