ip_input.c revision 1.245
1/* $NetBSD: ip_input.c,v 1.245 2007/03/05 00:50:53 liamjfoy 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. Neither the name of the University nor the names of its contributors 82 * may be used to endorse or promote products derived from this software 83 * without specific prior written permission. 84 * 85 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 86 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 87 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 88 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 89 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 90 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 91 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 92 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 93 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 94 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 95 * SUCH DAMAGE. 96 * 97 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 98 */ 99 100#include <sys/cdefs.h> 101__KERNEL_RCSID(0, "$NetBSD: ip_input.c,v 1.245 2007/03/05 00:50:53 liamjfoy Exp $"); 102 103#include "opt_inet.h" 104#include "opt_gateway.h" 105#include "opt_pfil_hooks.h" 106#include "opt_ipsec.h" 107#include "opt_mrouting.h" 108#include "opt_mbuftrace.h" 109#include "opt_inet_csum.h" 110 111#include <sys/param.h> 112#include <sys/systm.h> 113#include <sys/malloc.h> 114#include <sys/mbuf.h> 115#include <sys/domain.h> 116#include <sys/protosw.h> 117#include <sys/socket.h> 118#include <sys/socketvar.h> 119#include <sys/errno.h> 120#include <sys/time.h> 121#include <sys/kernel.h> 122#include <sys/pool.h> 123#include <sys/sysctl.h> 124#include <sys/kauth.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_proto.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#ifdef FAST_IPSEC 154#include <netipsec/ipsec.h> 155#include <netipsec/key.h> 156#endif /* FAST_IPSEC*/ 157 158#ifndef IPFORWARDING 159#ifdef GATEWAY 160#define IPFORWARDING 1 /* forward IP packets not for us */ 161#else /* GATEWAY */ 162#define IPFORWARDING 0 /* don't forward IP packets not for us */ 163#endif /* GATEWAY */ 164#endif /* IPFORWARDING */ 165#ifndef IPSENDREDIRECTS 166#define IPSENDREDIRECTS 1 167#endif 168#ifndef IPFORWSRCRT 169#define IPFORWSRCRT 1 /* forward source-routed packets */ 170#endif 171#ifndef IPALLOWSRCRT 172#define IPALLOWSRCRT 1 /* allow source-routed packets */ 173#endif 174#ifndef IPMTUDISC 175#define IPMTUDISC 1 176#endif 177#ifndef IPMTUDISCTIMEOUT 178#define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */ 179#endif 180 181/* 182 * Note: DIRECTED_BROADCAST is handled this way so that previous 183 * configuration using this option will Just Work. 184 */ 185#ifndef IPDIRECTEDBCAST 186#ifdef DIRECTED_BROADCAST 187#define IPDIRECTEDBCAST 1 188#else 189#define IPDIRECTEDBCAST 0 190#endif /* DIRECTED_BROADCAST */ 191#endif /* IPDIRECTEDBCAST */ 192int ipforwarding = IPFORWARDING; 193int ipsendredirects = IPSENDREDIRECTS; 194int ip_defttl = IPDEFTTL; 195int ip_forwsrcrt = IPFORWSRCRT; 196int ip_directedbcast = IPDIRECTEDBCAST; 197int ip_allowsrcrt = IPALLOWSRCRT; 198int ip_mtudisc = IPMTUDISC; 199int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 200#ifdef DIAGNOSTIC 201int ipprintfs = 0; 202#endif 203 204int ip_do_randomid = 0; 205 206/* 207 * XXX - Setting ip_checkinterface mostly implements the receive side of 208 * the Strong ES model described in RFC 1122, but since the routing table 209 * and transmit implementation do not implement the Strong ES model, 210 * setting this to 1 results in an odd hybrid. 211 * 212 * XXX - ip_checkinterface currently must be disabled if you use ipnat 213 * to translate the destination address to another local interface. 214 * 215 * XXX - ip_checkinterface must be disabled if you add IP aliases 216 * to the loopback interface instead of the interface where the 217 * packets for those addresses are received. 218 */ 219int ip_checkinterface = 0; 220 221 222struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 223 224int ipqmaxlen = IFQ_MAXLEN; 225u_long in_ifaddrhash; /* size of hash table - 1 */ 226int in_ifaddrentries; /* total number of addrs */ 227struct in_ifaddrhead in_ifaddrhead; 228struct in_ifaddrhashhead *in_ifaddrhashtbl; 229u_long in_multihash; /* size of hash table - 1 */ 230int in_multientries; /* total number of addrs */ 231struct in_multihashhead *in_multihashtbl; 232struct ifqueue ipintrq; 233struct ipstat ipstat; 234uint16_t ip_id; 235 236#ifdef PFIL_HOOKS 237struct pfil_head inet_pfil_hook; 238#endif 239 240/* 241 * Cached copy of nmbclusters. If nbclusters is different, 242 * recalculate IP parameters derived from nmbclusters. 243 */ 244static int ip_nmbclusters; /* copy of nmbclusters */ 245static void ip_nmbclusters_changed(void); /* recalc limits */ 246 247#define CHECK_NMBCLUSTER_PARAMS() \ 248do { \ 249 if (__predict_false(ip_nmbclusters != nmbclusters)) \ 250 ip_nmbclusters_changed(); \ 251} while (/*CONSTCOND*/0) 252 253/* IP datagram reassembly queues (hashed) */ 254#define IPREASS_NHASH_LOG2 6 255#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 256#define IPREASS_HMASK (IPREASS_NHASH - 1) 257#define IPREASS_HASH(x,y) \ 258 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 259struct ipqhead ipq[IPREASS_NHASH]; 260int ipq_locked; 261static int ip_nfragpackets; /* packets in reass queue */ 262static int ip_nfrags; /* total fragments in reass queues */ 263 264int ip_maxfragpackets = 200; /* limit on packets. XXX sysctl */ 265int ip_maxfrags; /* limit on fragments. XXX sysctl */ 266 267 268/* 269 * Additive-Increase/Multiplicative-Decrease (AIMD) strategy for 270 * IP reassembly queue buffer managment. 271 * 272 * We keep a count of total IP fragments (NB: not fragmented packets!) 273 * awaiting reassembly (ip_nfrags) and a limit (ip_maxfrags) on fragments. 274 * If ip_nfrags exceeds ip_maxfrags the limit, we drop half the 275 * total fragments in reassembly queues.This AIMD policy avoids 276 * repeatedly deleting single packets under heavy fragmentation load 277 * (e.g., from lossy NFS peers). 278 */ 279static u_int ip_reass_ttl_decr(u_int ticks); 280static void ip_reass_drophalf(void); 281 282 283static inline int ipq_lock_try(void); 284static inline void ipq_unlock(void); 285 286static inline int 287ipq_lock_try(void) 288{ 289 int s; 290 291 /* 292 * Use splvm() -- we're blocking things that would cause 293 * mbuf allocation. 294 */ 295 s = splvm(); 296 if (ipq_locked) { 297 splx(s); 298 return (0); 299 } 300 ipq_locked = 1; 301 splx(s); 302 return (1); 303} 304 305static inline void 306ipq_unlock(void) 307{ 308 int s; 309 310 s = splvm(); 311 ipq_locked = 0; 312 splx(s); 313} 314 315#ifdef DIAGNOSTIC 316#define IPQ_LOCK() \ 317do { \ 318 if (ipq_lock_try() == 0) { \ 319 printf("%s:%d: ipq already locked\n", __FILE__, __LINE__); \ 320 panic("ipq_lock"); \ 321 } \ 322} while (/*CONSTCOND*/ 0) 323#define IPQ_LOCK_CHECK() \ 324do { \ 325 if (ipq_locked == 0) { \ 326 printf("%s:%d: ipq lock not held\n", __FILE__, __LINE__); \ 327 panic("ipq lock check"); \ 328 } \ 329} while (/*CONSTCOND*/ 0) 330#else 331#define IPQ_LOCK() (void) ipq_lock_try() 332#define IPQ_LOCK_CHECK() /* nothing */ 333#endif 334 335#define IPQ_UNLOCK() ipq_unlock() 336 337POOL_INIT(inmulti_pool, sizeof(struct in_multi), 0, 0, 0, "inmltpl", NULL); 338POOL_INIT(ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl", NULL); 339 340#ifdef INET_CSUM_COUNTERS 341#include <sys/device.h> 342 343struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 344 NULL, "inet", "hwcsum bad"); 345struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 346 NULL, "inet", "hwcsum ok"); 347struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 348 NULL, "inet", "swcsum"); 349 350#define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 351 352EVCNT_ATTACH_STATIC(ip_hwcsum_bad); 353EVCNT_ATTACH_STATIC(ip_hwcsum_ok); 354EVCNT_ATTACH_STATIC(ip_swcsum); 355 356#else 357 358#define INET_CSUM_COUNTER_INCR(ev) /* nothing */ 359 360#endif /* INET_CSUM_COUNTERS */ 361 362/* 363 * We need to save the IP options in case a protocol wants to respond 364 * to an incoming packet over the same route if the packet got here 365 * using IP source routing. This allows connection establishment and 366 * maintenance when the remote end is on a network that is not known 367 * to us. 368 */ 369int ip_nhops = 0; 370static struct ip_srcrt { 371 struct in_addr dst; /* final destination */ 372 char nop; /* one NOP to align */ 373 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 374 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 375} ip_srcrt; 376 377static void save_rte(u_char *, struct in_addr); 378 379#ifdef MBUFTRACE 380struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx"); 381struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx"); 382#endif 383 384/* 385 * Compute IP limits derived from the value of nmbclusters. 386 */ 387static void 388ip_nmbclusters_changed(void) 389{ 390 ip_maxfrags = nmbclusters / 4; 391 ip_nmbclusters = nmbclusters; 392} 393 394/* 395 * IP initialization: fill in IP protocol switch table. 396 * All protocols not implemented in kernel go to raw IP protocol handler. 397 */ 398void 399ip_init(void) 400{ 401 const struct protosw *pr; 402 int i; 403 404 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 405 if (pr == 0) 406 panic("ip_init"); 407 for (i = 0; i < IPPROTO_MAX; i++) 408 ip_protox[i] = pr - inetsw; 409 for (pr = inetdomain.dom_protosw; 410 pr < inetdomain.dom_protoswNPROTOSW; pr++) 411 if (pr->pr_domain->dom_family == PF_INET && 412 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 413 ip_protox[pr->pr_protocol] = pr - inetsw; 414 415 for (i = 0; i < IPREASS_NHASH; i++) 416 LIST_INIT(&ipq[i]); 417 418 ip_id = time_second & 0xfffff; 419 420 ipintrq.ifq_maxlen = ipqmaxlen; 421 ip_nmbclusters_changed(); 422 423 TAILQ_INIT(&in_ifaddrhead); 424 in_ifaddrhashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IFADDR, 425 M_WAITOK, &in_ifaddrhash); 426 in_multihashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IPMADDR, 427 M_WAITOK, &in_multihash); 428 ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout); 429#ifdef GATEWAY 430 ipflow_init(); 431#endif 432 433#ifdef PFIL_HOOKS 434 /* Register our Packet Filter hook. */ 435 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 436 inet_pfil_hook.ph_af = AF_INET; 437 i = pfil_head_register(&inet_pfil_hook); 438 if (i != 0) 439 printf("ip_init: WARNING: unable to register pfil hook, " 440 "error %d\n", i); 441#endif /* PFIL_HOOKS */ 442 443#ifdef MBUFTRACE 444 MOWNER_ATTACH(&ip_tx_mowner); 445 MOWNER_ATTACH(&ip_rx_mowner); 446#endif /* MBUFTRACE */ 447} 448 449struct sockaddr_in ipaddr = { 450 .sin_len = sizeof(ipaddr), 451 .sin_family = AF_INET, 452}; 453struct route ipforward_rt; 454 455/* 456 * IP software interrupt routine 457 */ 458void 459ipintr(void) 460{ 461 int s; 462 struct mbuf *m; 463 464 while (!IF_IS_EMPTY(&ipintrq)) { 465 s = splnet(); 466 IF_DEQUEUE(&ipintrq, m); 467 splx(s); 468 if (m == 0) 469 return; 470 MCLAIM(m, &ip_rx_mowner); 471 ip_input(m); 472 } 473} 474 475/* 476 * Ip input routine. Checksum and byte swap header. If fragmented 477 * try to reassemble. Process options. Pass to next level. 478 */ 479void 480ip_input(struct mbuf *m) 481{ 482 struct ip *ip = NULL; 483 struct ipq *fp; 484 struct in_ifaddr *ia; 485 struct ifaddr *ifa; 486 struct ipqent *ipqe; 487 int hlen = 0, mff, len; 488 int downmatch; 489 int checkif; 490 int srcrt = 0; 491 int s; 492 u_int hash; 493#ifdef FAST_IPSEC 494 struct m_tag *mtag; 495 struct tdb_ident *tdbi; 496 struct secpolicy *sp; 497 int error; 498#endif /* FAST_IPSEC */ 499 500 MCLAIM(m, &ip_rx_mowner); 501#ifdef DIAGNOSTIC 502 if ((m->m_flags & M_PKTHDR) == 0) 503 panic("ipintr no HDR"); 504#endif 505 506 /* 507 * If no IP addresses have been set yet but the interfaces 508 * are receiving, can't do anything with incoming packets yet. 509 */ 510 if (TAILQ_FIRST(&in_ifaddrhead) == 0) 511 goto bad; 512 ipstat.ips_total++; 513 /* 514 * If the IP header is not aligned, slurp it up into a new 515 * mbuf with space for link headers, in the event we forward 516 * it. Otherwise, if it is aligned, make sure the entire 517 * base IP header is in the first mbuf of the chain. 518 */ 519 if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) { 520 if ((m = m_copyup(m, sizeof(struct ip), 521 (max_linkhdr + 3) & ~3)) == NULL) { 522 /* XXXJRT new stat, please */ 523 ipstat.ips_toosmall++; 524 return; 525 } 526 } else if (__predict_false(m->m_len < sizeof (struct ip))) { 527 if ((m = m_pullup(m, sizeof (struct ip))) == NULL) { 528 ipstat.ips_toosmall++; 529 return; 530 } 531 } 532 ip = mtod(m, struct ip *); 533 if (ip->ip_v != IPVERSION) { 534 ipstat.ips_badvers++; 535 goto bad; 536 } 537 hlen = ip->ip_hl << 2; 538 if (hlen < sizeof(struct ip)) { /* minimum header length */ 539 ipstat.ips_badhlen++; 540 goto bad; 541 } 542 if (hlen > m->m_len) { 543 if ((m = m_pullup(m, hlen)) == 0) { 544 ipstat.ips_badhlen++; 545 return; 546 } 547 ip = mtod(m, struct ip *); 548 } 549 550 /* 551 * RFC1122: packets with a multicast source address are 552 * not allowed. 553 */ 554 if (IN_MULTICAST(ip->ip_src.s_addr)) { 555 ipstat.ips_badaddr++; 556 goto bad; 557 } 558 559 /* 127/8 must not appear on wire - RFC1122 */ 560 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 561 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 562 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 563 ipstat.ips_badaddr++; 564 goto bad; 565 } 566 } 567 568 switch (m->m_pkthdr.csum_flags & 569 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_IPv4) | 570 M_CSUM_IPv4_BAD)) { 571 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 572 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad); 573 goto badcsum; 574 575 case M_CSUM_IPv4: 576 /* Checksum was okay. */ 577 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok); 578 break; 579 580 default: 581 /* 582 * Must compute it ourselves. Maybe skip checksum on 583 * loopback interfaces. 584 */ 585 if (__predict_true(!(m->m_pkthdr.rcvif->if_flags & 586 IFF_LOOPBACK) || ip_do_loopback_cksum)) { 587 INET_CSUM_COUNTER_INCR(&ip_swcsum); 588 if (in_cksum(m, hlen) != 0) 589 goto badcsum; 590 } 591 break; 592 } 593 594 /* Retrieve the packet length. */ 595 len = ntohs(ip->ip_len); 596 597 /* 598 * Check for additional length bogosity 599 */ 600 if (len < hlen) { 601 ipstat.ips_badlen++; 602 goto bad; 603 } 604 605 /* 606 * Check that the amount of data in the buffers 607 * is as at least much as the IP header would have us expect. 608 * Trim mbufs if longer than we expect. 609 * Drop packet if shorter than we expect. 610 */ 611 if (m->m_pkthdr.len < len) { 612 ipstat.ips_tooshort++; 613 goto bad; 614 } 615 if (m->m_pkthdr.len > len) { 616 if (m->m_len == m->m_pkthdr.len) { 617 m->m_len = len; 618 m->m_pkthdr.len = len; 619 } else 620 m_adj(m, len - m->m_pkthdr.len); 621 } 622 623#if defined(IPSEC) 624 /* ipflow (IP fast forwarding) is not compatible with IPsec. */ 625 m->m_flags &= ~M_CANFASTFWD; 626#else 627 /* 628 * Assume that we can create a fast-forward IP flow entry 629 * based on this packet. 630 */ 631 m->m_flags |= M_CANFASTFWD; 632#endif 633 634#ifdef PFIL_HOOKS 635 /* 636 * Run through list of hooks for input packets. If there are any 637 * filters which require that additional packets in the flow are 638 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 639 * Note that filters must _never_ set this flag, as another filter 640 * in the list may have previously cleared it. 641 */ 642 /* 643 * let ipfilter look at packet on the wire, 644 * not the decapsulated packet. 645 */ 646#ifdef IPSEC 647 if (!ipsec_getnhist(m)) 648#elif defined(FAST_IPSEC) 649 if (!ipsec_indone(m)) 650#else 651 if (1) 652#endif 653 { 654 struct in_addr odst; 655 656 odst = ip->ip_dst; 657 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 658 PFIL_IN) != 0) 659 return; 660 if (m == NULL) 661 return; 662 ip = mtod(m, struct ip *); 663 hlen = ip->ip_hl << 2; 664 /* 665 * XXX The setting of "srcrt" here is to prevent ip_forward() 666 * from generating ICMP redirects for packets that have 667 * been redirected by a hook back out on to the same LAN that 668 * they came from and is not an indication that the packet 669 * is being inffluenced by source routing options. This 670 * allows things like 671 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp" 672 * where tlp0 is both on the 1.1.1.0/24 network and is the 673 * default route for hosts on 1.1.1.0/24. Of course this 674 * also requires a "map tlp0 ..." to complete the story. 675 * One might argue whether or not this kind of network config. 676 * should be supported in this manner... 677 */ 678 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 679 } 680#endif /* PFIL_HOOKS */ 681 682#ifdef ALTQ 683 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 684 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 685 /* packet dropped by traffic conditioner */ 686 return; 687 } 688#endif 689 690 /* 691 * Process options and, if not destined for us, 692 * ship it on. ip_dooptions returns 1 when an 693 * error was detected (causing an icmp message 694 * to be sent and the original packet to be freed). 695 */ 696 ip_nhops = 0; /* for source routed packets */ 697 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 698 return; 699 700 /* 701 * Enable a consistency check between the destination address 702 * and the arrival interface for a unicast packet (the RFC 1122 703 * strong ES model) if IP forwarding is disabled and the packet 704 * is not locally generated. 705 * 706 * XXX - Checking also should be disabled if the destination 707 * address is ipnat'ed to a different interface. 708 * 709 * XXX - Checking is incompatible with IP aliases added 710 * to the loopback interface instead of the interface where 711 * the packets are received. 712 * 713 * XXX - We need to add a per ifaddr flag for this so that 714 * we get finer grain control. 715 */ 716 checkif = ip_checkinterface && (ipforwarding == 0) && 717 (m->m_pkthdr.rcvif != NULL) && 718 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0); 719 720 /* 721 * Check our list of addresses, to see if the packet is for us. 722 * 723 * Traditional 4.4BSD did not consult IFF_UP at all. 724 * The behavior here is to treat addresses on !IFF_UP interface 725 * as not mine. 726 */ 727 downmatch = 0; 728 LIST_FOREACH(ia, &IN_IFADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 729 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) { 730 if (checkif && ia->ia_ifp != m->m_pkthdr.rcvif) 731 continue; 732 if ((ia->ia_ifp->if_flags & IFF_UP) != 0) 733 break; 734 else 735 downmatch++; 736 } 737 } 738 if (ia != NULL) 739 goto ours; 740 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 741 IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) { 742 if (ifa->ifa_addr->sa_family != AF_INET) 743 continue; 744 ia = ifatoia(ifa); 745 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 746 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 747 /* 748 * Look for all-0's host part (old broadcast addr), 749 * either for subnet or net. 750 */ 751 ip->ip_dst.s_addr == ia->ia_subnet || 752 ip->ip_dst.s_addr == ia->ia_net) 753 goto ours; 754 /* 755 * An interface with IP address zero accepts 756 * all packets that arrive on that interface. 757 */ 758 if (in_nullhost(ia->ia_addr.sin_addr)) 759 goto ours; 760 } 761 } 762 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 763 struct in_multi *inm; 764#ifdef MROUTING 765 extern struct socket *ip_mrouter; 766 767 if (ip_mrouter) { 768 /* 769 * If we are acting as a multicast router, all 770 * incoming multicast packets are passed to the 771 * kernel-level multicast forwarding function. 772 * The packet is returned (relatively) intact; if 773 * ip_mforward() returns a non-zero value, the packet 774 * must be discarded, else it may be accepted below. 775 * 776 * (The IP ident field is put in the same byte order 777 * as expected when ip_mforward() is called from 778 * ip_output().) 779 */ 780 if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) { 781 ipstat.ips_cantforward++; 782 m_freem(m); 783 return; 784 } 785 786 /* 787 * The process-level routing demon needs to receive 788 * all multicast IGMP packets, whether or not this 789 * host belongs to their destination groups. 790 */ 791 if (ip->ip_p == IPPROTO_IGMP) 792 goto ours; 793 ipstat.ips_forward++; 794 } 795#endif 796 /* 797 * See if we belong to the destination multicast group on the 798 * arrival interface. 799 */ 800 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 801 if (inm == NULL) { 802 ipstat.ips_cantforward++; 803 m_freem(m); 804 return; 805 } 806 goto ours; 807 } 808 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 809 in_nullhost(ip->ip_dst)) 810 goto ours; 811 812 /* 813 * Not for us; forward if possible and desirable. 814 */ 815 if (ipforwarding == 0) { 816 ipstat.ips_cantforward++; 817 m_freem(m); 818 } else { 819 /* 820 * If ip_dst matched any of my address on !IFF_UP interface, 821 * and there's no IFF_UP interface that matches ip_dst, 822 * send icmp unreach. Forwarding it will result in in-kernel 823 * forwarding loop till TTL goes to 0. 824 */ 825 if (downmatch) { 826 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 827 ipstat.ips_cantforward++; 828 return; 829 } 830#ifdef IPSEC 831 if (ipsec4_in_reject(m, NULL)) { 832 ipsecstat.in_polvio++; 833 goto bad; 834 } 835#endif 836#ifdef FAST_IPSEC 837 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 838 s = splsoftnet(); 839 if (mtag != NULL) { 840 tdbi = (struct tdb_ident *)(mtag + 1); 841 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 842 } else { 843 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 844 IP_FORWARDING, &error); 845 } 846 if (sp == NULL) { /* NB: can happen if error */ 847 splx(s); 848 /*XXX error stat???*/ 849 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 850 goto bad; 851 } 852 853 /* 854 * Check security policy against packet attributes. 855 */ 856 error = ipsec_in_reject(sp, m); 857 KEY_FREESP(&sp); 858 splx(s); 859 if (error) { 860 ipstat.ips_cantforward++; 861 goto bad; 862 } 863 864 /* 865 * Peek at the outbound SP for this packet to determine if 866 * it's a Fast Forward candidate. 867 */ 868 mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 869 if (mtag != NULL) 870 m->m_flags &= ~M_CANFASTFWD; 871 else { 872 s = splsoftnet(); 873 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, 874 (IP_FORWARDING | 875 (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 876 &error, NULL); 877 if (sp != NULL) { 878 m->m_flags &= ~M_CANFASTFWD; 879 KEY_FREESP(&sp); 880 } 881 splx(s); 882 } 883#endif /* FAST_IPSEC */ 884 885 ip_forward(m, srcrt); 886 } 887 return; 888 889ours: 890 /* 891 * If offset or IP_MF are set, must reassemble. 892 * Otherwise, nothing need be done. 893 * (We could look in the reassembly queue to see 894 * if the packet was previously fragmented, 895 * but it's not worth the time; just let them time out.) 896 */ 897 if (ip->ip_off & ~htons(IP_DF|IP_RF)) { 898 899 /* 900 * Look for queue of fragments 901 * of this datagram. 902 */ 903 IPQ_LOCK(); 904 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 905 /* XXX LIST_FOREACH(fp, &ipq[hash], ipq_q) */ 906 for (fp = LIST_FIRST(&ipq[hash]); fp != NULL; 907 fp = LIST_NEXT(fp, ipq_q)) { 908 if (ip->ip_id == fp->ipq_id && 909 in_hosteq(ip->ip_src, fp->ipq_src) && 910 in_hosteq(ip->ip_dst, fp->ipq_dst) && 911 ip->ip_p == fp->ipq_p) 912 goto found; 913 914 } 915 fp = 0; 916found: 917 918 /* 919 * Adjust ip_len to not reflect header, 920 * set ipqe_mff if more fragments are expected, 921 * convert offset of this to bytes. 922 */ 923 ip->ip_len = htons(ntohs(ip->ip_len) - hlen); 924 mff = (ip->ip_off & htons(IP_MF)) != 0; 925 if (mff) { 926 /* 927 * Make sure that fragments have a data length 928 * that's a non-zero multiple of 8 bytes. 929 */ 930 if (ntohs(ip->ip_len) == 0 || 931 (ntohs(ip->ip_len) & 0x7) != 0) { 932 ipstat.ips_badfrags++; 933 IPQ_UNLOCK(); 934 goto bad; 935 } 936 } 937 ip->ip_off = htons((ntohs(ip->ip_off) & IP_OFFMASK) << 3); 938 939 /* 940 * If datagram marked as having more fragments 941 * or if this is not the first fragment, 942 * attempt reassembly; if it succeeds, proceed. 943 */ 944 if (mff || ip->ip_off != htons(0)) { 945 ipstat.ips_fragments++; 946 s = splvm(); 947 ipqe = pool_get(&ipqent_pool, PR_NOWAIT); 948 splx(s); 949 if (ipqe == NULL) { 950 ipstat.ips_rcvmemdrop++; 951 IPQ_UNLOCK(); 952 goto bad; 953 } 954 ipqe->ipqe_mff = mff; 955 ipqe->ipqe_m = m; 956 ipqe->ipqe_ip = ip; 957 m = ip_reass(ipqe, fp, &ipq[hash]); 958 if (m == 0) { 959 IPQ_UNLOCK(); 960 return; 961 } 962 ipstat.ips_reassembled++; 963 ip = mtod(m, struct ip *); 964 hlen = ip->ip_hl << 2; 965 ip->ip_len = htons(ntohs(ip->ip_len) + hlen); 966 } else 967 if (fp) 968 ip_freef(fp); 969 IPQ_UNLOCK(); 970 } 971 972#if defined(IPSEC) 973 /* 974 * enforce IPsec policy checking if we are seeing last header. 975 * note that we do not visit this with protocols with pcb layer 976 * code - like udp/tcp/raw ip. 977 */ 978 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 979 ipsec4_in_reject(m, NULL)) { 980 ipsecstat.in_polvio++; 981 goto bad; 982 } 983#endif 984#ifdef FAST_IPSEC 985 /* 986 * enforce IPsec policy checking if we are seeing last header. 987 * note that we do not visit this with protocols with pcb layer 988 * code - like udp/tcp/raw ip. 989 */ 990 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 991 /* 992 * Check if the packet has already had IPsec processing 993 * done. If so, then just pass it along. This tag gets 994 * set during AH, ESP, etc. input handling, before the 995 * packet is returned to the ip input queue for delivery. 996 */ 997 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 998 s = splsoftnet(); 999 if (mtag != NULL) { 1000 tdbi = (struct tdb_ident *)(mtag + 1); 1001 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 1002 } else { 1003 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 1004 IP_FORWARDING, &error); 1005 } 1006 if (sp != NULL) { 1007 /* 1008 * Check security policy against packet attributes. 1009 */ 1010 error = ipsec_in_reject(sp, m); 1011 KEY_FREESP(&sp); 1012 } else { 1013 /* XXX error stat??? */ 1014 error = EINVAL; 1015DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 1016 goto bad; 1017 } 1018 splx(s); 1019 if (error) 1020 goto bad; 1021 } 1022#endif /* FAST_IPSEC */ 1023 1024 /* 1025 * Switch out to protocol's input routine. 1026 */ 1027#if IFA_STATS 1028 if (ia && ip) 1029 ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len); 1030#endif 1031 ipstat.ips_delivered++; 1032 { 1033 int off = hlen, nh = ip->ip_p; 1034 1035 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 1036 return; 1037 } 1038bad: 1039 m_freem(m); 1040 return; 1041 1042badcsum: 1043 ipstat.ips_badsum++; 1044 m_freem(m); 1045} 1046 1047/* 1048 * Take incoming datagram fragment and try to 1049 * reassemble it into whole datagram. If a chain for 1050 * reassembly of this datagram already exists, then it 1051 * is given as fp; otherwise have to make a chain. 1052 */ 1053struct mbuf * 1054ip_reass(struct ipqent *ipqe, struct ipq *fp, struct ipqhead *ipqhead) 1055{ 1056 struct mbuf *m = ipqe->ipqe_m; 1057 struct ipqent *nq, *p, *q; 1058 struct ip *ip; 1059 struct mbuf *t; 1060 int hlen = ipqe->ipqe_ip->ip_hl << 2; 1061 int i, next, s; 1062 1063 IPQ_LOCK_CHECK(); 1064 1065 /* 1066 * Presence of header sizes in mbufs 1067 * would confuse code below. 1068 */ 1069 m->m_data += hlen; 1070 m->m_len -= hlen; 1071 1072#ifdef notyet 1073 /* make sure fragment limit is up-to-date */ 1074 CHECK_NMBCLUSTER_PARAMS(); 1075 1076 /* If we have too many fragments, drop the older half. */ 1077 if (ip_nfrags >= ip_maxfrags) 1078 ip_reass_drophalf(void); 1079#endif 1080 1081 /* 1082 * We are about to add a fragment; increment frag count. 1083 */ 1084 ip_nfrags++; 1085 1086 /* 1087 * If first fragment to arrive, create a reassembly queue. 1088 */ 1089 if (fp == 0) { 1090 /* 1091 * Enforce upper bound on number of fragmented packets 1092 * for which we attempt reassembly; 1093 * If maxfrag is 0, never accept fragments. 1094 * If maxfrag is -1, accept all fragments without limitation. 1095 */ 1096 if (ip_maxfragpackets < 0) 1097 ; 1098 else if (ip_nfragpackets >= ip_maxfragpackets) 1099 goto dropfrag; 1100 ip_nfragpackets++; 1101 MALLOC(fp, struct ipq *, sizeof (struct ipq), 1102 M_FTABLE, M_NOWAIT); 1103 if (fp == NULL) 1104 goto dropfrag; 1105 LIST_INSERT_HEAD(ipqhead, fp, ipq_q); 1106 fp->ipq_nfrags = 1; 1107 fp->ipq_ttl = IPFRAGTTL; 1108 fp->ipq_p = ipqe->ipqe_ip->ip_p; 1109 fp->ipq_id = ipqe->ipqe_ip->ip_id; 1110 TAILQ_INIT(&fp->ipq_fragq); 1111 fp->ipq_src = ipqe->ipqe_ip->ip_src; 1112 fp->ipq_dst = ipqe->ipqe_ip->ip_dst; 1113 p = NULL; 1114 goto insert; 1115 } else { 1116 fp->ipq_nfrags++; 1117 } 1118 1119 /* 1120 * Find a segment which begins after this one does. 1121 */ 1122 for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; 1123 p = q, q = TAILQ_NEXT(q, ipqe_q)) 1124 if (ntohs(q->ipqe_ip->ip_off) > ntohs(ipqe->ipqe_ip->ip_off)) 1125 break; 1126 1127 /* 1128 * If there is a preceding segment, it may provide some of 1129 * our data already. If so, drop the data from the incoming 1130 * segment. If it provides all of our data, drop us. 1131 */ 1132 if (p != NULL) { 1133 i = ntohs(p->ipqe_ip->ip_off) + ntohs(p->ipqe_ip->ip_len) - 1134 ntohs(ipqe->ipqe_ip->ip_off); 1135 if (i > 0) { 1136 if (i >= ntohs(ipqe->ipqe_ip->ip_len)) 1137 goto dropfrag; 1138 m_adj(ipqe->ipqe_m, i); 1139 ipqe->ipqe_ip->ip_off = 1140 htons(ntohs(ipqe->ipqe_ip->ip_off) + i); 1141 ipqe->ipqe_ip->ip_len = 1142 htons(ntohs(ipqe->ipqe_ip->ip_len) - i); 1143 } 1144 } 1145 1146 /* 1147 * While we overlap succeeding segments trim them or, 1148 * if they are completely covered, dequeue them. 1149 */ 1150 for (; q != NULL && 1151 ntohs(ipqe->ipqe_ip->ip_off) + ntohs(ipqe->ipqe_ip->ip_len) > 1152 ntohs(q->ipqe_ip->ip_off); q = nq) { 1153 i = (ntohs(ipqe->ipqe_ip->ip_off) + 1154 ntohs(ipqe->ipqe_ip->ip_len)) - ntohs(q->ipqe_ip->ip_off); 1155 if (i < ntohs(q->ipqe_ip->ip_len)) { 1156 q->ipqe_ip->ip_len = 1157 htons(ntohs(q->ipqe_ip->ip_len) - i); 1158 q->ipqe_ip->ip_off = 1159 htons(ntohs(q->ipqe_ip->ip_off) + i); 1160 m_adj(q->ipqe_m, i); 1161 break; 1162 } 1163 nq = TAILQ_NEXT(q, ipqe_q); 1164 m_freem(q->ipqe_m); 1165 TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q); 1166 s = splvm(); 1167 pool_put(&ipqent_pool, q); 1168 splx(s); 1169 fp->ipq_nfrags--; 1170 ip_nfrags--; 1171 } 1172 1173insert: 1174 /* 1175 * Stick new segment in its place; 1176 * check for complete reassembly. 1177 */ 1178 if (p == NULL) { 1179 TAILQ_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); 1180 } else { 1181 TAILQ_INSERT_AFTER(&fp->ipq_fragq, p, ipqe, ipqe_q); 1182 } 1183 next = 0; 1184 for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; 1185 p = q, q = TAILQ_NEXT(q, ipqe_q)) { 1186 if (ntohs(q->ipqe_ip->ip_off) != next) 1187 return (0); 1188 next += ntohs(q->ipqe_ip->ip_len); 1189 } 1190 if (p->ipqe_mff) 1191 return (0); 1192 1193 /* 1194 * Reassembly is complete. Check for a bogus message size and 1195 * concatenate fragments. 1196 */ 1197 q = TAILQ_FIRST(&fp->ipq_fragq); 1198 ip = q->ipqe_ip; 1199 if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) { 1200 ipstat.ips_toolong++; 1201 ip_freef(fp); 1202 return (0); 1203 } 1204 m = q->ipqe_m; 1205 t = m->m_next; 1206 m->m_next = 0; 1207 m_cat(m, t); 1208 nq = TAILQ_NEXT(q, ipqe_q); 1209 s = splvm(); 1210 pool_put(&ipqent_pool, q); 1211 splx(s); 1212 for (q = nq; q != NULL; q = nq) { 1213 t = q->ipqe_m; 1214 nq = TAILQ_NEXT(q, ipqe_q); 1215 s = splvm(); 1216 pool_put(&ipqent_pool, q); 1217 splx(s); 1218 m_cat(m, t); 1219 } 1220 ip_nfrags -= fp->ipq_nfrags; 1221 1222 /* 1223 * Create header for new ip packet by 1224 * modifying header of first packet; 1225 * dequeue and discard fragment reassembly header. 1226 * Make header visible. 1227 */ 1228 ip->ip_len = htons(next); 1229 ip->ip_src = fp->ipq_src; 1230 ip->ip_dst = fp->ipq_dst; 1231 LIST_REMOVE(fp, ipq_q); 1232 FREE(fp, M_FTABLE); 1233 ip_nfragpackets--; 1234 m->m_len += (ip->ip_hl << 2); 1235 m->m_data -= (ip->ip_hl << 2); 1236 /* some debugging cruft by sklower, below, will go away soon */ 1237 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1238 int plen = 0; 1239 for (t = m; t; t = t->m_next) 1240 plen += t->m_len; 1241 m->m_pkthdr.len = plen; 1242 m->m_pkthdr.csum_flags = 0; 1243 } 1244 return (m); 1245 1246dropfrag: 1247 if (fp != 0) 1248 fp->ipq_nfrags--; 1249 ip_nfrags--; 1250 ipstat.ips_fragdropped++; 1251 m_freem(m); 1252 s = splvm(); 1253 pool_put(&ipqent_pool, ipqe); 1254 splx(s); 1255 return (0); 1256} 1257 1258/* 1259 * Free a fragment reassembly header and all 1260 * associated datagrams. 1261 */ 1262void 1263ip_freef(struct ipq *fp) 1264{ 1265 struct ipqent *q, *p; 1266 u_int nfrags = 0; 1267 int s; 1268 1269 IPQ_LOCK_CHECK(); 1270 1271 for (q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; q = p) { 1272 p = TAILQ_NEXT(q, ipqe_q); 1273 m_freem(q->ipqe_m); 1274 nfrags++; 1275 TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q); 1276 s = splvm(); 1277 pool_put(&ipqent_pool, q); 1278 splx(s); 1279 } 1280 1281 if (nfrags != fp->ipq_nfrags) 1282 printf("ip_freef: nfrags %d != %d\n", fp->ipq_nfrags, nfrags); 1283 ip_nfrags -= nfrags; 1284 LIST_REMOVE(fp, ipq_q); 1285 FREE(fp, M_FTABLE); 1286 ip_nfragpackets--; 1287} 1288 1289/* 1290 * IP reassembly TTL machinery for multiplicative drop. 1291 */ 1292static u_int fragttl_histo[(IPFRAGTTL+1)]; 1293 1294 1295/* 1296 * Decrement TTL of all reasembly queue entries by `ticks'. 1297 * Count number of distinct fragments (as opposed to partial, fragmented 1298 * datagrams) in the reassembly queue. While we traverse the entire 1299 * reassembly queue, compute and return the median TTL over all fragments. 1300 */ 1301static u_int 1302ip_reass_ttl_decr(u_int ticks) 1303{ 1304 u_int nfrags, median, dropfraction, keepfraction; 1305 struct ipq *fp, *nfp; 1306 int i; 1307 1308 nfrags = 0; 1309 memset(fragttl_histo, 0, sizeof fragttl_histo); 1310 1311 for (i = 0; i < IPREASS_NHASH; i++) { 1312 for (fp = LIST_FIRST(&ipq[i]); fp != NULL; fp = nfp) { 1313 fp->ipq_ttl = ((fp->ipq_ttl <= ticks) ? 1314 0 : fp->ipq_ttl - ticks); 1315 nfp = LIST_NEXT(fp, ipq_q); 1316 if (fp->ipq_ttl == 0) { 1317 ipstat.ips_fragtimeout++; 1318 ip_freef(fp); 1319 } else { 1320 nfrags += fp->ipq_nfrags; 1321 fragttl_histo[fp->ipq_ttl] += fp->ipq_nfrags; 1322 } 1323 } 1324 } 1325 1326 KASSERT(ip_nfrags == nfrags); 1327 1328 /* Find median (or other drop fraction) in histogram. */ 1329 dropfraction = (ip_nfrags / 2); 1330 keepfraction = ip_nfrags - dropfraction; 1331 for (i = IPFRAGTTL, median = 0; i >= 0; i--) { 1332 median += fragttl_histo[i]; 1333 if (median >= keepfraction) 1334 break; 1335 } 1336 1337 /* Return TTL of median (or other fraction). */ 1338 return (u_int)i; 1339} 1340 1341void 1342ip_reass_drophalf(void) 1343{ 1344 1345 u_int median_ticks; 1346 /* 1347 * Compute median TTL of all fragments, and count frags 1348 * with that TTL or lower (roughly half of all fragments). 1349 */ 1350 median_ticks = ip_reass_ttl_decr(0); 1351 1352 /* Drop half. */ 1353 median_ticks = ip_reass_ttl_decr(median_ticks); 1354 1355} 1356 1357/* 1358 * IP timer processing; 1359 * if a timer expires on a reassembly 1360 * queue, discard it. 1361 */ 1362void 1363ip_slowtimo(void) 1364{ 1365 static u_int dropscanidx = 0; 1366 u_int i; 1367 u_int median_ttl; 1368 int s = splsoftnet(); 1369 1370 IPQ_LOCK(); 1371 1372 /* Age TTL of all fragments by 1 tick .*/ 1373 median_ttl = ip_reass_ttl_decr(1); 1374 1375 /* make sure fragment limit is up-to-date */ 1376 CHECK_NMBCLUSTER_PARAMS(); 1377 1378 /* If we have too many fragments, drop the older half. */ 1379 if (ip_nfrags > ip_maxfrags) 1380 ip_reass_ttl_decr(median_ttl); 1381 1382 /* 1383 * If we are over the maximum number of fragmented packets 1384 * (due to the limit being lowered), drain off 1385 * enough to get down to the new limit. Start draining 1386 * from the reassembly hashqueue most recently drained. 1387 */ 1388 if (ip_maxfragpackets < 0) 1389 ; 1390 else { 1391 int wrapped = 0; 1392 1393 i = dropscanidx; 1394 while (ip_nfragpackets > ip_maxfragpackets && wrapped == 0) { 1395 while (LIST_FIRST(&ipq[i]) != NULL) 1396 ip_freef(LIST_FIRST(&ipq[i])); 1397 if (++i >= IPREASS_NHASH) { 1398 i = 0; 1399 } 1400 /* 1401 * Dont scan forever even if fragment counters are 1402 * wrong: stop after scanning entire reassembly queue. 1403 */ 1404 if (i == dropscanidx) 1405 wrapped = 1; 1406 } 1407 dropscanidx = i; 1408 } 1409 IPQ_UNLOCK(); 1410 splx(s); 1411} 1412 1413/* 1414 * Drain off all datagram fragments. 1415 */ 1416void 1417ip_drain(void) 1418{ 1419 1420 /* 1421 * We may be called from a device's interrupt context. If 1422 * the ipq is already busy, just bail out now. 1423 */ 1424 if (ipq_lock_try() == 0) 1425 return; 1426 1427 /* 1428 * Drop half the total fragments now. If more mbufs are needed, 1429 * we will be called again soon. 1430 */ 1431 ip_reass_drophalf(); 1432 1433 IPQ_UNLOCK(); 1434} 1435 1436/* 1437 * Do option processing on a datagram, 1438 * possibly discarding it if bad options are encountered, 1439 * or forwarding it if source-routed. 1440 * Returns 1 if packet has been forwarded/freed, 1441 * 0 if the packet should be processed further. 1442 */ 1443int 1444ip_dooptions(struct mbuf *m) 1445{ 1446 struct ip *ip = mtod(m, struct ip *); 1447 u_char *cp, *cp0; 1448 struct ip_timestamp *ipt; 1449 struct in_ifaddr *ia; 1450 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1451 struct in_addr dst; 1452 n_time ntime; 1453 1454 dst = ip->ip_dst; 1455 cp = (u_char *)(ip + 1); 1456 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1457 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1458 opt = cp[IPOPT_OPTVAL]; 1459 if (opt == IPOPT_EOL) 1460 break; 1461 if (opt == IPOPT_NOP) 1462 optlen = 1; 1463 else { 1464 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1465 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1466 goto bad; 1467 } 1468 optlen = cp[IPOPT_OLEN]; 1469 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1470 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1471 goto bad; 1472 } 1473 } 1474 switch (opt) { 1475 1476 default: 1477 break; 1478 1479 /* 1480 * Source routing with record. 1481 * Find interface with current destination address. 1482 * If none on this machine then drop if strictly routed, 1483 * or do nothing if loosely routed. 1484 * Record interface address and bring up next address 1485 * component. If strictly routed make sure next 1486 * address is on directly accessible net. 1487 */ 1488 case IPOPT_LSRR: 1489 case IPOPT_SSRR: 1490 if (ip_allowsrcrt == 0) { 1491 type = ICMP_UNREACH; 1492 code = ICMP_UNREACH_NET_PROHIB; 1493 goto bad; 1494 } 1495 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1496 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1497 goto bad; 1498 } 1499 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1500 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1501 goto bad; 1502 } 1503 ipaddr.sin_addr = ip->ip_dst; 1504 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); 1505 if (ia == 0) { 1506 if (opt == IPOPT_SSRR) { 1507 type = ICMP_UNREACH; 1508 code = ICMP_UNREACH_SRCFAIL; 1509 goto bad; 1510 } 1511 /* 1512 * Loose routing, and not at next destination 1513 * yet; nothing to do except forward. 1514 */ 1515 break; 1516 } 1517 off--; /* 0 origin */ 1518 if ((off + sizeof(struct in_addr)) > optlen) { 1519 /* 1520 * End of source route. Should be for us. 1521 */ 1522 save_rte(cp, ip->ip_src); 1523 break; 1524 } 1525 /* 1526 * locate outgoing interface 1527 */ 1528 bcopy((void *)(cp + off), (void *)&ipaddr.sin_addr, 1529 sizeof(ipaddr.sin_addr)); 1530 if (opt == IPOPT_SSRR) 1531 ia = ifatoia(ifa_ifwithladdr(sintosa(&ipaddr))); 1532 else 1533 ia = ip_rtaddr(ipaddr.sin_addr); 1534 if (ia == 0) { 1535 type = ICMP_UNREACH; 1536 code = ICMP_UNREACH_SRCFAIL; 1537 goto bad; 1538 } 1539 ip->ip_dst = ipaddr.sin_addr; 1540 bcopy((void *)&ia->ia_addr.sin_addr, 1541 (void *)(cp + off), sizeof(struct in_addr)); 1542 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1543 /* 1544 * Let ip_intr's mcast routing check handle mcast pkts 1545 */ 1546 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1547 break; 1548 1549 case IPOPT_RR: 1550 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1551 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1552 goto bad; 1553 } 1554 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1555 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1556 goto bad; 1557 } 1558 /* 1559 * If no space remains, ignore. 1560 */ 1561 off--; /* 0 origin */ 1562 if ((off + sizeof(struct in_addr)) > optlen) 1563 break; 1564 bcopy((void *)(&ip->ip_dst), (void *)&ipaddr.sin_addr, 1565 sizeof(ipaddr.sin_addr)); 1566 /* 1567 * locate outgoing interface; if we're the destination, 1568 * use the incoming interface (should be same). 1569 */ 1570 if ((ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)))) 1571 == NULL && 1572 (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) { 1573 type = ICMP_UNREACH; 1574 code = ICMP_UNREACH_HOST; 1575 goto bad; 1576 } 1577 bcopy((void *)&ia->ia_addr.sin_addr, 1578 (void *)(cp + off), sizeof(struct in_addr)); 1579 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1580 break; 1581 1582 case IPOPT_TS: 1583 code = cp - (u_char *)ip; 1584 ipt = (struct ip_timestamp *)cp; 1585 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1586 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1587 goto bad; 1588 } 1589 if (ipt->ipt_ptr < 5) { 1590 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1591 goto bad; 1592 } 1593 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) { 1594 if (++ipt->ipt_oflw == 0) { 1595 code = (u_char *)&ipt->ipt_ptr - 1596 (u_char *)ip; 1597 goto bad; 1598 } 1599 break; 1600 } 1601 cp0 = (cp + ipt->ipt_ptr - 1); 1602 switch (ipt->ipt_flg) { 1603 1604 case IPOPT_TS_TSONLY: 1605 break; 1606 1607 case IPOPT_TS_TSANDADDR: 1608 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1609 sizeof(struct in_addr) > ipt->ipt_len) { 1610 code = (u_char *)&ipt->ipt_ptr - 1611 (u_char *)ip; 1612 goto bad; 1613 } 1614 ipaddr.sin_addr = dst; 1615 ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr), 1616 m->m_pkthdr.rcvif)); 1617 if (ia == 0) 1618 continue; 1619 bcopy(&ia->ia_addr.sin_addr, 1620 cp0, sizeof(struct in_addr)); 1621 ipt->ipt_ptr += sizeof(struct in_addr); 1622 break; 1623 1624 case IPOPT_TS_PRESPEC: 1625 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1626 sizeof(struct in_addr) > ipt->ipt_len) { 1627 code = (u_char *)&ipt->ipt_ptr - 1628 (u_char *)ip; 1629 goto bad; 1630 } 1631 bcopy(cp0, &ipaddr.sin_addr, 1632 sizeof(struct in_addr)); 1633 if (ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))) 1634 == NULL) 1635 continue; 1636 ipt->ipt_ptr += sizeof(struct in_addr); 1637 break; 1638 1639 default: 1640 /* XXX can't take &ipt->ipt_flg */ 1641 code = (u_char *)&ipt->ipt_ptr - 1642 (u_char *)ip + 1; 1643 goto bad; 1644 } 1645 ntime = iptime(); 1646 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1647 memmove((char *)cp + ipt->ipt_ptr - 1, cp0, 1648 sizeof(n_time)); 1649 ipt->ipt_ptr += sizeof(n_time); 1650 } 1651 } 1652 if (forward) { 1653 if (ip_forwsrcrt == 0) { 1654 type = ICMP_UNREACH; 1655 code = ICMP_UNREACH_SRCFAIL; 1656 goto bad; 1657 } 1658 ip_forward(m, 1); 1659 return (1); 1660 } 1661 return (0); 1662bad: 1663 icmp_error(m, type, code, 0, 0); 1664 ipstat.ips_badoptions++; 1665 return (1); 1666} 1667 1668/* 1669 * Given address of next destination (final or next hop), 1670 * return internet address info of interface to be used to get there. 1671 */ 1672struct in_ifaddr * 1673ip_rtaddr(struct in_addr dst) 1674{ 1675 if (!in_hosteq(dst, satocsin(rtcache_getdst(&ipforward_rt))->sin_addr)) 1676 rtcache_free(&ipforward_rt); 1677 else 1678 rtcache_check(&ipforward_rt); 1679 1680 if (ipforward_rt.ro_rt == NULL) { 1681 struct sockaddr_in *sin = satosin(&ipforward_rt.ro_dst); 1682 1683 sin->sin_family = AF_INET; 1684 sin->sin_len = sizeof(*sin); 1685 sin->sin_addr = dst; 1686 1687 rtcache_init(&ipforward_rt); 1688 if (ipforward_rt.ro_rt == NULL) 1689 return NULL; 1690 } 1691 return ifatoia(ipforward_rt.ro_rt->rt_ifa); 1692} 1693 1694/* 1695 * Save incoming source route for use in replies, 1696 * to be picked up later by ip_srcroute if the receiver is interested. 1697 */ 1698void 1699save_rte(u_char *option, struct in_addr dst) 1700{ 1701 unsigned olen; 1702 1703 olen = option[IPOPT_OLEN]; 1704#ifdef DIAGNOSTIC 1705 if (ipprintfs) 1706 printf("save_rte: olen %d\n", olen); 1707#endif /* 0 */ 1708 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1709 return; 1710 bcopy((void *)option, (void *)ip_srcrt.srcopt, olen); 1711 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1712 ip_srcrt.dst = dst; 1713} 1714 1715/* 1716 * Retrieve incoming source route for use in replies, 1717 * in the same form used by setsockopt. 1718 * The first hop is placed before the options, will be removed later. 1719 */ 1720struct mbuf * 1721ip_srcroute(void) 1722{ 1723 struct in_addr *p, *q; 1724 struct mbuf *m; 1725 1726 if (ip_nhops == 0) 1727 return NULL; 1728 m = m_get(M_DONTWAIT, MT_SOOPTS); 1729 if (m == 0) 1730 return NULL; 1731 1732 MCLAIM(m, &inetdomain.dom_mowner); 1733#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1734 1735 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1736 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1737 OPTSIZ; 1738#ifdef DIAGNOSTIC 1739 if (ipprintfs) 1740 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1741#endif 1742 1743 /* 1744 * First save first hop for return route 1745 */ 1746 p = &ip_srcrt.route[ip_nhops - 1]; 1747 *(mtod(m, struct in_addr *)) = *p--; 1748#ifdef DIAGNOSTIC 1749 if (ipprintfs) 1750 printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1751#endif 1752 1753 /* 1754 * Copy option fields and padding (nop) to mbuf. 1755 */ 1756 ip_srcrt.nop = IPOPT_NOP; 1757 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1758 memmove(mtod(m, char *) + sizeof(struct in_addr), &ip_srcrt.nop, 1759 OPTSIZ); 1760 q = (struct in_addr *)(mtod(m, char *) + 1761 sizeof(struct in_addr) + OPTSIZ); 1762#undef OPTSIZ 1763 /* 1764 * Record return path as an IP source route, 1765 * reversing the path (pointers are now aligned). 1766 */ 1767 while (p >= ip_srcrt.route) { 1768#ifdef DIAGNOSTIC 1769 if (ipprintfs) 1770 printf(" %x", ntohl(q->s_addr)); 1771#endif 1772 *q++ = *p--; 1773 } 1774 /* 1775 * Last hop goes to final destination. 1776 */ 1777 *q = ip_srcrt.dst; 1778#ifdef DIAGNOSTIC 1779 if (ipprintfs) 1780 printf(" %x\n", ntohl(q->s_addr)); 1781#endif 1782 return (m); 1783} 1784 1785/* 1786 * Strip out IP options, at higher 1787 * level protocol in the kernel. 1788 * Second argument is buffer to which options 1789 * will be moved, and return value is their length. 1790 * XXX should be deleted; last arg currently ignored. 1791 */ 1792void 1793ip_stripoptions(struct mbuf *m, struct mbuf *mopt) 1794{ 1795 int i; 1796 struct ip *ip = mtod(m, struct ip *); 1797 void *opts; 1798 int olen; 1799 1800 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1801 opts = (void *)(ip + 1); 1802 i = m->m_len - (sizeof (struct ip) + olen); 1803 memmove(opts, (char *)opts + olen, (unsigned)i); 1804 m->m_len -= olen; 1805 if (m->m_flags & M_PKTHDR) 1806 m->m_pkthdr.len -= olen; 1807 ip->ip_len = htons(ntohs(ip->ip_len) - olen); 1808 ip->ip_hl = sizeof (struct ip) >> 2; 1809} 1810 1811const int inetctlerrmap[PRC_NCMDS] = { 1812 0, 0, 0, 0, 1813 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1814 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1815 EMSGSIZE, EHOSTUNREACH, 0, 0, 1816 0, 0, 0, 0, 1817 ENOPROTOOPT 1818}; 1819 1820/* 1821 * Forward a packet. If some error occurs return the sender 1822 * an icmp packet. Note we can't always generate a meaningful 1823 * icmp message because icmp doesn't have a large enough repertoire 1824 * of codes and types. 1825 * 1826 * If not forwarding, just drop the packet. This could be confusing 1827 * if ipforwarding was zero but some routing protocol was advancing 1828 * us as a gateway to somewhere. However, we must let the routing 1829 * protocol deal with that. 1830 * 1831 * The srcrt parameter indicates whether the packet is being forwarded 1832 * via a source route. 1833 */ 1834void 1835ip_forward(struct mbuf *m, int srcrt) 1836{ 1837 struct ip *ip = mtod(m, struct ip *); 1838 struct rtentry *rt; 1839 int error, type = 0, code = 0, destmtu = 0; 1840 struct mbuf *mcopy; 1841 n_long dest; 1842 1843 /* 1844 * We are now in the output path. 1845 */ 1846 MCLAIM(m, &ip_tx_mowner); 1847 1848 /* 1849 * Clear any in-bound checksum flags for this packet. 1850 */ 1851 m->m_pkthdr.csum_flags = 0; 1852 1853 dest = 0; 1854#ifdef DIAGNOSTIC 1855 if (ipprintfs) { 1856 printf("forward: src %s ", inet_ntoa(ip->ip_src)); 1857 printf("dst %s ttl %x\n", inet_ntoa(ip->ip_dst), ip->ip_ttl); 1858 } 1859#endif 1860 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1861 ipstat.ips_cantforward++; 1862 m_freem(m); 1863 return; 1864 } 1865 if (ip->ip_ttl <= IPTTLDEC) { 1866 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1867 return; 1868 } 1869 1870 if (!in_hosteq(ip->ip_dst, 1871 satocsin(rtcache_getdst(&ipforward_rt))->sin_addr)) 1872 rtcache_free(&ipforward_rt); 1873 else 1874 rtcache_check(&ipforward_rt); 1875 if (ipforward_rt.ro_rt == NULL) { 1876 struct sockaddr_in *sin = satosin(&ipforward_rt.ro_dst); 1877 1878 sin->sin_family = AF_INET; 1879 sin->sin_len = sizeof(*sin); 1880 sin->sin_addr = ip->ip_dst; 1881 1882 rtcache_init(&ipforward_rt); 1883 if (ipforward_rt.ro_rt == NULL) { 1884 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0); 1885 return; 1886 } 1887 } 1888 rt = ipforward_rt.ro_rt; 1889 1890 /* 1891 * Save at most 68 bytes of the packet in case 1892 * we need to generate an ICMP message to the src. 1893 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1894 */ 1895 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1896 if (mcopy) 1897 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1898 1899 ip->ip_ttl -= IPTTLDEC; 1900 1901 /* 1902 * If forwarding packet using same interface that it came in on, 1903 * perhaps should send a redirect to sender to shortcut a hop. 1904 * Only send redirect if source is sending directly to us, 1905 * and if packet was not source routed (or has any options). 1906 * Also, don't send redirect if forwarding using a default route 1907 * or a route modified by a redirect. 1908 */ 1909 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1910 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1911 !in_nullhost(satosin(rt_key(rt))->sin_addr) && 1912 ipsendredirects && !srcrt) { 1913 if (rt->rt_ifa && 1914 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1915 ifatoia(rt->rt_ifa)->ia_subnet) { 1916 if (rt->rt_flags & RTF_GATEWAY) 1917 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1918 else 1919 dest = ip->ip_dst.s_addr; 1920 /* 1921 * Router requirements says to only send host 1922 * redirects. 1923 */ 1924 type = ICMP_REDIRECT; 1925 code = ICMP_REDIRECT_HOST; 1926#ifdef DIAGNOSTIC 1927 if (ipprintfs) 1928 printf("redirect (%d) to %x\n", code, 1929 (u_int32_t)dest); 1930#endif 1931 } 1932 } 1933 1934 error = ip_output(m, NULL, &ipforward_rt, 1935 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1936 (struct ip_moptions *)NULL, (struct socket *)NULL); 1937 1938 if (error) 1939 ipstat.ips_cantforward++; 1940 else { 1941 ipstat.ips_forward++; 1942 if (type) 1943 ipstat.ips_redirectsent++; 1944 else { 1945 if (mcopy) { 1946#ifdef GATEWAY 1947 if (mcopy->m_flags & M_CANFASTFWD) 1948 ipflow_create(&ipforward_rt, mcopy); 1949#endif 1950 m_freem(mcopy); 1951 } 1952 return; 1953 } 1954 } 1955 if (mcopy == NULL) 1956 return; 1957 1958 switch (error) { 1959 1960 case 0: /* forwarded, but need redirect */ 1961 /* type, code set above */ 1962 break; 1963 1964 case ENETUNREACH: /* shouldn't happen, checked above */ 1965 case EHOSTUNREACH: 1966 case ENETDOWN: 1967 case EHOSTDOWN: 1968 default: 1969 type = ICMP_UNREACH; 1970 code = ICMP_UNREACH_HOST; 1971 break; 1972 1973 case EMSGSIZE: 1974 type = ICMP_UNREACH; 1975 code = ICMP_UNREACH_NEEDFRAG; 1976#if !defined(IPSEC) && !defined(FAST_IPSEC) 1977 if (ipforward_rt.ro_rt != NULL) 1978 destmtu = ipforward_rt.ro_rt->rt_ifp->if_mtu; 1979#else 1980 /* 1981 * If the packet is routed over IPsec tunnel, tell the 1982 * originator the tunnel MTU. 1983 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1984 * XXX quickhack!!! 1985 */ 1986 if (ipforward_rt.ro_rt != NULL) { 1987 struct secpolicy *sp; 1988 int ipsecerror; 1989 size_t ipsechdr; 1990 struct route *ro; 1991 1992 sp = ipsec4_getpolicybyaddr(mcopy, 1993 IPSEC_DIR_OUTBOUND, IP_FORWARDING, 1994 &ipsecerror); 1995 1996 if (sp == NULL) 1997 destmtu = ipforward_rt.ro_rt->rt_ifp->if_mtu; 1998 else { 1999 /* count IPsec header size */ 2000 ipsechdr = ipsec4_hdrsiz(mcopy, 2001 IPSEC_DIR_OUTBOUND, NULL); 2002 2003 /* 2004 * find the correct route for outer IPv4 2005 * header, compute tunnel MTU. 2006 */ 2007 2008 if (sp->req != NULL 2009 && sp->req->sav != NULL 2010 && sp->req->sav->sah != NULL) { 2011 ro = &sp->req->sav->sah->sa_route; 2012 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 2013 destmtu = 2014 ro->ro_rt->rt_rmx.rmx_mtu ? 2015 ro->ro_rt->rt_rmx.rmx_mtu : 2016 ro->ro_rt->rt_ifp->if_mtu; 2017 destmtu -= ipsechdr; 2018 } 2019 } 2020 2021#ifdef IPSEC 2022 key_freesp(sp); 2023#else 2024 KEY_FREESP(&sp); 2025#endif 2026 } 2027 } 2028#endif /*IPSEC*/ 2029 ipstat.ips_cantfrag++; 2030 break; 2031 2032 case ENOBUFS: 2033#if 1 2034 /* 2035 * a router should not generate ICMP_SOURCEQUENCH as 2036 * required in RFC1812 Requirements for IP Version 4 Routers. 2037 * source quench could be a big problem under DoS attacks, 2038 * or if the underlying interface is rate-limited. 2039 */ 2040 if (mcopy) 2041 m_freem(mcopy); 2042 return; 2043#else 2044 type = ICMP_SOURCEQUENCH; 2045 code = 0; 2046 break; 2047#endif 2048 } 2049 icmp_error(mcopy, type, code, dest, destmtu); 2050} 2051 2052void 2053ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2054 struct mbuf *m) 2055{ 2056 2057 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2058 struct timeval tv; 2059 2060 microtime(&tv); 2061 *mp = sbcreatecontrol((void *) &tv, sizeof(tv), 2062 SCM_TIMESTAMP, SOL_SOCKET); 2063 if (*mp) 2064 mp = &(*mp)->m_next; 2065 } 2066 if (inp->inp_flags & INP_RECVDSTADDR) { 2067 *mp = sbcreatecontrol((void *) &ip->ip_dst, 2068 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2069 if (*mp) 2070 mp = &(*mp)->m_next; 2071 } 2072#ifdef notyet 2073 /* 2074 * XXX 2075 * Moving these out of udp_input() made them even more broken 2076 * than they already were. 2077 * - fenner@parc.xerox.com 2078 */ 2079 /* options were tossed already */ 2080 if (inp->inp_flags & INP_RECVOPTS) { 2081 *mp = sbcreatecontrol((void *) opts_deleted_above, 2082 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2083 if (*mp) 2084 mp = &(*mp)->m_next; 2085 } 2086 /* ip_srcroute doesn't do what we want here, need to fix */ 2087 if (inp->inp_flags & INP_RECVRETOPTS) { 2088 *mp = sbcreatecontrol((void *) ip_srcroute(), 2089 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2090 if (*mp) 2091 mp = &(*mp)->m_next; 2092 } 2093#endif 2094 if (inp->inp_flags & INP_RECVIF) { 2095 struct sockaddr_dl sdl; 2096 2097 sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]); 2098 sdl.sdl_family = AF_LINK; 2099 sdl.sdl_index = m->m_pkthdr.rcvif ? 2100 m->m_pkthdr.rcvif->if_index : 0; 2101 sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0; 2102 *mp = sbcreatecontrol((void *) &sdl, sdl.sdl_len, 2103 IP_RECVIF, IPPROTO_IP); 2104 if (*mp) 2105 mp = &(*mp)->m_next; 2106 } 2107} 2108 2109/* 2110 * sysctl helper routine for net.inet.ip.forwsrcrt. 2111 */ 2112static int 2113sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS) 2114{ 2115 int error, tmp; 2116 struct sysctlnode node; 2117 2118 node = *rnode; 2119 tmp = ip_forwsrcrt; 2120 node.sysctl_data = &tmp; 2121 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 2122 if (error || newp == NULL) 2123 return (error); 2124 2125 if (kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT, 2126 0, NULL, NULL, NULL)) 2127 return (EPERM); 2128 2129 ip_forwsrcrt = tmp; 2130 2131 return (0); 2132} 2133 2134/* 2135 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the 2136 * range of the new value and tweaks timers if it changes. 2137 */ 2138static int 2139sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS) 2140{ 2141 int error, tmp; 2142 struct sysctlnode node; 2143 2144 node = *rnode; 2145 tmp = ip_mtudisc_timeout; 2146 node.sysctl_data = &tmp; 2147 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 2148 if (error || newp == NULL) 2149 return (error); 2150 if (tmp < 0) 2151 return (EINVAL); 2152 2153 ip_mtudisc_timeout = tmp; 2154 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout); 2155 2156 return (0); 2157} 2158 2159#ifdef GATEWAY 2160/* 2161 * sysctl helper routine for net.inet.ip.maxflows. apparently if 2162 * maxflows is even looked up, we "reap flows". 2163 */ 2164static int 2165sysctl_net_inet_ip_maxflows(SYSCTLFN_ARGS) 2166{ 2167 int s; 2168 2169 s = sysctl_lookup(SYSCTLFN_CALL(rnode)); 2170 if (s) 2171 return (s); 2172 2173 s = splsoftnet(); 2174 ipflow_reap(0); 2175 splx(s); 2176 2177 return (0); 2178} 2179#endif /* GATEWAY */ 2180 2181 2182SYSCTL_SETUP(sysctl_net_inet_ip_setup, "sysctl net.inet.ip subtree setup") 2183{ 2184 extern int subnetsarelocal, hostzeroisbroadcast; 2185 2186 sysctl_createv(clog, 0, NULL, NULL, 2187 CTLFLAG_PERMANENT, 2188 CTLTYPE_NODE, "net", NULL, 2189 NULL, 0, NULL, 0, 2190 CTL_NET, CTL_EOL); 2191 sysctl_createv(clog, 0, NULL, NULL, 2192 CTLFLAG_PERMANENT, 2193 CTLTYPE_NODE, "inet", 2194 SYSCTL_DESCR("PF_INET related settings"), 2195 NULL, 0, NULL, 0, 2196 CTL_NET, PF_INET, CTL_EOL); 2197 sysctl_createv(clog, 0, NULL, NULL, 2198 CTLFLAG_PERMANENT, 2199 CTLTYPE_NODE, "ip", 2200 SYSCTL_DESCR("IPv4 related settings"), 2201 NULL, 0, NULL, 0, 2202 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL); 2203 2204 sysctl_createv(clog, 0, NULL, NULL, 2205 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2206 CTLTYPE_INT, "forwarding", 2207 SYSCTL_DESCR("Enable forwarding of INET datagrams"), 2208 NULL, 0, &ipforwarding, 0, 2209 CTL_NET, PF_INET, IPPROTO_IP, 2210 IPCTL_FORWARDING, CTL_EOL); 2211 sysctl_createv(clog, 0, NULL, NULL, 2212 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2213 CTLTYPE_INT, "redirect", 2214 SYSCTL_DESCR("Enable sending of ICMP redirect messages"), 2215 NULL, 0, &ipsendredirects, 0, 2216 CTL_NET, PF_INET, IPPROTO_IP, 2217 IPCTL_SENDREDIRECTS, CTL_EOL); 2218 sysctl_createv(clog, 0, NULL, NULL, 2219 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2220 CTLTYPE_INT, "ttl", 2221 SYSCTL_DESCR("Default TTL for an INET datagram"), 2222 NULL, 0, &ip_defttl, 0, 2223 CTL_NET, PF_INET, IPPROTO_IP, 2224 IPCTL_DEFTTL, CTL_EOL); 2225#ifdef IPCTL_DEFMTU 2226 sysctl_createv(clog, 0, NULL, NULL, 2227 CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */, 2228 CTLTYPE_INT, "mtu", 2229 SYSCTL_DESCR("Default MTA for an INET route"), 2230 NULL, 0, &ip_mtu, 0, 2231 CTL_NET, PF_INET, IPPROTO_IP, 2232 IPCTL_DEFMTU, CTL_EOL); 2233#endif /* IPCTL_DEFMTU */ 2234 sysctl_createv(clog, 0, NULL, NULL, 2235 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2236 CTLTYPE_INT, "forwsrcrt", 2237 SYSCTL_DESCR("Enable forwarding of source-routed " 2238 "datagrams"), 2239 sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0, 2240 CTL_NET, PF_INET, IPPROTO_IP, 2241 IPCTL_FORWSRCRT, CTL_EOL); 2242 sysctl_createv(clog, 0, NULL, NULL, 2243 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2244 CTLTYPE_INT, "directed-broadcast", 2245 SYSCTL_DESCR("Enable forwarding of broadcast datagrams"), 2246 NULL, 0, &ip_directedbcast, 0, 2247 CTL_NET, PF_INET, IPPROTO_IP, 2248 IPCTL_DIRECTEDBCAST, CTL_EOL); 2249 sysctl_createv(clog, 0, NULL, NULL, 2250 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2251 CTLTYPE_INT, "allowsrcrt", 2252 SYSCTL_DESCR("Accept source-routed datagrams"), 2253 NULL, 0, &ip_allowsrcrt, 0, 2254 CTL_NET, PF_INET, IPPROTO_IP, 2255 IPCTL_ALLOWSRCRT, CTL_EOL); 2256 sysctl_createv(clog, 0, NULL, NULL, 2257 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2258 CTLTYPE_INT, "subnetsarelocal", 2259 SYSCTL_DESCR("Whether logical subnets are considered " 2260 "local"), 2261 NULL, 0, &subnetsarelocal, 0, 2262 CTL_NET, PF_INET, IPPROTO_IP, 2263 IPCTL_SUBNETSARELOCAL, CTL_EOL); 2264 sysctl_createv(clog, 0, NULL, NULL, 2265 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2266 CTLTYPE_INT, "mtudisc", 2267 SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"), 2268 NULL, 0, &ip_mtudisc, 0, 2269 CTL_NET, PF_INET, IPPROTO_IP, 2270 IPCTL_MTUDISC, CTL_EOL); 2271 sysctl_createv(clog, 0, NULL, NULL, 2272 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2273 CTLTYPE_INT, "anonportmin", 2274 SYSCTL_DESCR("Lowest ephemeral port number to assign"), 2275 sysctl_net_inet_ip_ports, 0, &anonportmin, 0, 2276 CTL_NET, PF_INET, IPPROTO_IP, 2277 IPCTL_ANONPORTMIN, CTL_EOL); 2278 sysctl_createv(clog, 0, NULL, NULL, 2279 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2280 CTLTYPE_INT, "anonportmax", 2281 SYSCTL_DESCR("Highest ephemeral port number to assign"), 2282 sysctl_net_inet_ip_ports, 0, &anonportmax, 0, 2283 CTL_NET, PF_INET, IPPROTO_IP, 2284 IPCTL_ANONPORTMAX, CTL_EOL); 2285 sysctl_createv(clog, 0, NULL, NULL, 2286 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2287 CTLTYPE_INT, "mtudisctimeout", 2288 SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"), 2289 sysctl_net_inet_ip_pmtudto, 0, &ip_mtudisc_timeout, 0, 2290 CTL_NET, PF_INET, IPPROTO_IP, 2291 IPCTL_MTUDISCTIMEOUT, CTL_EOL); 2292#ifdef GATEWAY 2293 sysctl_createv(clog, 0, NULL, NULL, 2294 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2295 CTLTYPE_INT, "maxflows", 2296 SYSCTL_DESCR("Number of flows for fast forwarding"), 2297 sysctl_net_inet_ip_maxflows, 0, &ip_maxflows, 0, 2298 CTL_NET, PF_INET, IPPROTO_IP, 2299 IPCTL_MAXFLOWS, CTL_EOL); 2300#endif /* GATEWAY */ 2301 sysctl_createv(clog, 0, NULL, NULL, 2302 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2303 CTLTYPE_INT, "hostzerobroadcast", 2304 SYSCTL_DESCR("All zeroes address is broadcast address"), 2305 NULL, 0, &hostzeroisbroadcast, 0, 2306 CTL_NET, PF_INET, IPPROTO_IP, 2307 IPCTL_HOSTZEROBROADCAST, CTL_EOL); 2308#if NGIF > 0 2309 sysctl_createv(clog, 0, NULL, NULL, 2310 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2311 CTLTYPE_INT, "gifttl", 2312 SYSCTL_DESCR("Default TTL for a gif tunnel datagram"), 2313 NULL, 0, &ip_gif_ttl, 0, 2314 CTL_NET, PF_INET, IPPROTO_IP, 2315 IPCTL_GIF_TTL, CTL_EOL); 2316#endif /* NGIF */ 2317#ifndef IPNOPRIVPORTS 2318 sysctl_createv(clog, 0, NULL, NULL, 2319 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2320 CTLTYPE_INT, "lowportmin", 2321 SYSCTL_DESCR("Lowest privileged ephemeral port number " 2322 "to assign"), 2323 sysctl_net_inet_ip_ports, 0, &lowportmin, 0, 2324 CTL_NET, PF_INET, IPPROTO_IP, 2325 IPCTL_LOWPORTMIN, CTL_EOL); 2326 sysctl_createv(clog, 0, NULL, NULL, 2327 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2328 CTLTYPE_INT, "lowportmax", 2329 SYSCTL_DESCR("Highest privileged ephemeral port number " 2330 "to assign"), 2331 sysctl_net_inet_ip_ports, 0, &lowportmax, 0, 2332 CTL_NET, PF_INET, IPPROTO_IP, 2333 IPCTL_LOWPORTMAX, CTL_EOL); 2334#endif /* IPNOPRIVPORTS */ 2335 sysctl_createv(clog, 0, NULL, NULL, 2336 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2337 CTLTYPE_INT, "maxfragpackets", 2338 SYSCTL_DESCR("Maximum number of fragments to retain for " 2339 "possible reassembly"), 2340 NULL, 0, &ip_maxfragpackets, 0, 2341 CTL_NET, PF_INET, IPPROTO_IP, 2342 IPCTL_MAXFRAGPACKETS, CTL_EOL); 2343#if NGRE > 0 2344 sysctl_createv(clog, 0, NULL, NULL, 2345 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2346 CTLTYPE_INT, "grettl", 2347 SYSCTL_DESCR("Default TTL for a gre tunnel datagram"), 2348 NULL, 0, &ip_gre_ttl, 0, 2349 CTL_NET, PF_INET, IPPROTO_IP, 2350 IPCTL_GRE_TTL, CTL_EOL); 2351#endif /* NGRE */ 2352 sysctl_createv(clog, 0, NULL, NULL, 2353 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2354 CTLTYPE_INT, "checkinterface", 2355 SYSCTL_DESCR("Enable receive side of Strong ES model " 2356 "from RFC1122"), 2357 NULL, 0, &ip_checkinterface, 0, 2358 CTL_NET, PF_INET, IPPROTO_IP, 2359 IPCTL_CHECKINTERFACE, CTL_EOL); 2360 sysctl_createv(clog, 0, NULL, NULL, 2361 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2362 CTLTYPE_INT, "random_id", 2363 SYSCTL_DESCR("Assign random ip_id values"), 2364 NULL, 0, &ip_do_randomid, 0, 2365 CTL_NET, PF_INET, IPPROTO_IP, 2366 IPCTL_RANDOMID, CTL_EOL); 2367 sysctl_createv(clog, 0, NULL, NULL, 2368 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2369 CTLTYPE_INT, "do_loopback_cksum", 2370 SYSCTL_DESCR("Perform IP checksum on loopback"), 2371 NULL, 0, &ip_do_loopback_cksum, 0, 2372 CTL_NET, PF_INET, IPPROTO_IP, 2373 IPCTL_LOOPBACKCKSUM, CTL_EOL); 2374 sysctl_createv(clog, 0, NULL, NULL, 2375 CTLFLAG_PERMANENT, 2376 CTLTYPE_STRUCT, "stats", 2377 SYSCTL_DESCR("IP statistics"), 2378 NULL, 0, &ipstat, sizeof(ipstat), 2379 CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS, 2380 CTL_EOL); 2381} 2382