ip_input.c revision 1.258
1/* $NetBSD: ip_input.c,v 1.258 2007/12/21 18:58:55 matt 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 1.258 2007/12/21 18:58:55 matt 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, 338 IPL_SOFTNET); 339POOL_INIT(ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl", NULL, 340 IPL_VM); 341 342#ifdef INET_CSUM_COUNTERS 343#include <sys/device.h> 344 345struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 346 NULL, "inet", "hwcsum bad"); 347struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 348 NULL, "inet", "hwcsum ok"); 349struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 350 NULL, "inet", "swcsum"); 351 352#define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 353 354EVCNT_ATTACH_STATIC(ip_hwcsum_bad); 355EVCNT_ATTACH_STATIC(ip_hwcsum_ok); 356EVCNT_ATTACH_STATIC(ip_swcsum); 357 358#else 359 360#define INET_CSUM_COUNTER_INCR(ev) /* nothing */ 361 362#endif /* INET_CSUM_COUNTERS */ 363 364/* 365 * We need to save the IP options in case a protocol wants to respond 366 * to an incoming packet over the same route if the packet got here 367 * using IP source routing. This allows connection establishment and 368 * maintenance when the remote end is on a network that is not known 369 * to us. 370 */ 371int ip_nhops = 0; 372static struct ip_srcrt { 373 struct in_addr dst; /* final destination */ 374 char nop; /* one NOP to align */ 375 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 376 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 377} ip_srcrt; 378 379static void save_rte(u_char *, struct in_addr); 380 381#ifdef MBUFTRACE 382struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx"); 383struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx"); 384#endif 385 386/* 387 * Compute IP limits derived from the value of nmbclusters. 388 */ 389static void 390ip_nmbclusters_changed(void) 391{ 392 ip_maxfrags = nmbclusters / 4; 393 ip_nmbclusters = nmbclusters; 394} 395 396/* 397 * IP initialization: fill in IP protocol switch table. 398 * All protocols not implemented in kernel go to raw IP protocol handler. 399 */ 400void 401ip_init(void) 402{ 403 const struct protosw *pr; 404 int i; 405 406 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 407 if (pr == 0) 408 panic("ip_init"); 409 for (i = 0; i < IPPROTO_MAX; i++) 410 ip_protox[i] = pr - inetsw; 411 for (pr = inetdomain.dom_protosw; 412 pr < inetdomain.dom_protoswNPROTOSW; pr++) 413 if (pr->pr_domain->dom_family == PF_INET && 414 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 415 ip_protox[pr->pr_protocol] = pr - inetsw; 416 417 for (i = 0; i < IPREASS_NHASH; i++) 418 LIST_INIT(&ipq[i]); 419 420 ip_id = time_second & 0xfffff; 421 422 ipintrq.ifq_maxlen = ipqmaxlen; 423 ip_nmbclusters_changed(); 424 425 TAILQ_INIT(&in_ifaddrhead); 426 in_ifaddrhashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IFADDR, 427 M_WAITOK, &in_ifaddrhash); 428 in_multihashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IPMADDR, 429 M_WAITOK, &in_multihash); 430 ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout); 431#ifdef GATEWAY 432 ipflow_init(ip_hashsize); 433#endif 434 435#ifdef PFIL_HOOKS 436 /* Register our Packet Filter hook. */ 437 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 438 inet_pfil_hook.ph_af = AF_INET; 439 i = pfil_head_register(&inet_pfil_hook); 440 if (i != 0) 441 printf("ip_init: WARNING: unable to register pfil hook, " 442 "error %d\n", i); 443#endif /* PFIL_HOOKS */ 444 445#ifdef MBUFTRACE 446 MOWNER_ATTACH(&ip_tx_mowner); 447 MOWNER_ATTACH(&ip_rx_mowner); 448#endif /* MBUFTRACE */ 449} 450 451struct sockaddr_in ipaddr = { 452 .sin_len = sizeof(ipaddr), 453 .sin_family = AF_INET, 454}; 455struct route ipforward_rt; 456 457/* 458 * IP software interrupt routine 459 */ 460void 461ipintr(void) 462{ 463 int s; 464 struct mbuf *m; 465 466 while (!IF_IS_EMPTY(&ipintrq)) { 467 s = splnet(); 468 IF_DEQUEUE(&ipintrq, m); 469 splx(s); 470 if (m == 0) 471 return; 472 ip_input(m); 473 } 474} 475 476/* 477 * Ip input routine. Checksum and byte swap header. If fragmented 478 * try to reassemble. Process options. Pass to next level. 479 */ 480void 481ip_input(struct mbuf *m) 482{ 483 struct ip *ip = NULL; 484 struct ipq *fp; 485 struct in_ifaddr *ia; 486 struct ifaddr *ifa; 487 struct ipqent *ipqe; 488 int hlen = 0, mff, len; 489 int downmatch; 490 int checkif; 491 int srcrt = 0; 492 int s; 493 u_int hash; 494#ifdef FAST_IPSEC 495 struct m_tag *mtag; 496 struct tdb_ident *tdbi; 497 struct secpolicy *sp; 498 int error; 499#endif /* FAST_IPSEC */ 500 501 MCLAIM(m, &ip_rx_mowner); 502#ifdef DIAGNOSTIC 503 if ((m->m_flags & M_PKTHDR) == 0) 504 panic("ipintr no HDR"); 505#endif 506 507 /* 508 * If no IP addresses have been set yet but the interfaces 509 * are receiving, can't do anything with incoming packets yet. 510 */ 511 if (TAILQ_FIRST(&in_ifaddrhead) == 0) 512 goto bad; 513 ipstat.ips_total++; 514 /* 515 * If the IP header is not aligned, slurp it up into a new 516 * mbuf with space for link headers, in the event we forward 517 * it. Otherwise, if it is aligned, make sure the entire 518 * base IP header is in the first mbuf of the chain. 519 */ 520 if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) { 521 if ((m = m_copyup(m, sizeof(struct ip), 522 (max_linkhdr + 3) & ~3)) == NULL) { 523 /* XXXJRT new stat, please */ 524 ipstat.ips_toosmall++; 525 return; 526 } 527 } else if (__predict_false(m->m_len < sizeof (struct ip))) { 528 if ((m = m_pullup(m, sizeof (struct ip))) == NULL) { 529 ipstat.ips_toosmall++; 530 return; 531 } 532 } 533 ip = mtod(m, struct ip *); 534 if (ip->ip_v != IPVERSION) { 535 ipstat.ips_badvers++; 536 goto bad; 537 } 538 hlen = ip->ip_hl << 2; 539 if (hlen < sizeof(struct ip)) { /* minimum header length */ 540 ipstat.ips_badhlen++; 541 goto bad; 542 } 543 if (hlen > m->m_len) { 544 if ((m = m_pullup(m, hlen)) == 0) { 545 ipstat.ips_badhlen++; 546 return; 547 } 548 ip = mtod(m, struct ip *); 549 } 550 551 /* 552 * RFC1122: packets with a multicast source address are 553 * not allowed. 554 */ 555 if (IN_MULTICAST(ip->ip_src.s_addr)) { 556 ipstat.ips_badaddr++; 557 goto bad; 558 } 559 560 /* 127/8 must not appear on wire - RFC1122 */ 561 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 562 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 563 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 564 ipstat.ips_badaddr++; 565 goto bad; 566 } 567 } 568 569 switch (m->m_pkthdr.csum_flags & 570 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_IPv4) | 571 M_CSUM_IPv4_BAD)) { 572 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 573 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad); 574 goto badcsum; 575 576 case M_CSUM_IPv4: 577 /* Checksum was okay. */ 578 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok); 579 break; 580 581 default: 582 /* 583 * Must compute it ourselves. Maybe skip checksum on 584 * loopback interfaces. 585 */ 586 if (__predict_true(!(m->m_pkthdr.rcvif->if_flags & 587 IFF_LOOPBACK) || ip_do_loopback_cksum)) { 588 INET_CSUM_COUNTER_INCR(&ip_swcsum); 589 if (in_cksum(m, hlen) != 0) 590 goto badcsum; 591 } 592 break; 593 } 594 595 /* Retrieve the packet length. */ 596 len = ntohs(ip->ip_len); 597 598 /* 599 * Check for additional length bogosity 600 */ 601 if (len < hlen) { 602 ipstat.ips_badlen++; 603 goto bad; 604 } 605 606 /* 607 * Check that the amount of data in the buffers 608 * is as at least much as the IP header would have us expect. 609 * Trim mbufs if longer than we expect. 610 * Drop packet if shorter than we expect. 611 */ 612 if (m->m_pkthdr.len < len) { 613 ipstat.ips_tooshort++; 614 goto bad; 615 } 616 if (m->m_pkthdr.len > len) { 617 if (m->m_len == m->m_pkthdr.len) { 618 m->m_len = len; 619 m->m_pkthdr.len = len; 620 } else 621 m_adj(m, len - m->m_pkthdr.len); 622 } 623 624#if defined(IPSEC) 625 /* ipflow (IP fast forwarding) is not compatible with IPsec. */ 626 m->m_flags &= ~M_CANFASTFWD; 627#else 628 /* 629 * Assume that we can create a fast-forward IP flow entry 630 * based on this packet. 631 */ 632 m->m_flags |= M_CANFASTFWD; 633#endif 634 635#ifdef PFIL_HOOKS 636 /* 637 * Run through list of hooks for input packets. If there are any 638 * filters which require that additional packets in the flow are 639 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 640 * Note that filters must _never_ set this flag, as another filter 641 * in the list may have previously cleared it. 642 */ 643 /* 644 * let ipfilter look at packet on the wire, 645 * not the decapsulated packet. 646 */ 647#ifdef IPSEC 648 if (!ipsec_getnhist(m)) 649#elif defined(FAST_IPSEC) 650 if (!ipsec_indone(m)) 651#else 652 if (1) 653#endif 654 { 655 struct in_addr odst; 656 657 odst = ip->ip_dst; 658 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 659 PFIL_IN) != 0) 660 return; 661 if (m == NULL) 662 return; 663 ip = mtod(m, struct ip *); 664 hlen = ip->ip_hl << 2; 665 /* 666 * XXX The setting of "srcrt" here is to prevent ip_forward() 667 * from generating ICMP redirects for packets that have 668 * been redirected by a hook back out on to the same LAN that 669 * they came from and is not an indication that the packet 670 * is being inffluenced by source routing options. This 671 * allows things like 672 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp" 673 * where tlp0 is both on the 1.1.1.0/24 network and is the 674 * default route for hosts on 1.1.1.0/24. Of course this 675 * also requires a "map tlp0 ..." to complete the story. 676 * One might argue whether or not this kind of network config. 677 * should be supported in this manner... 678 */ 679 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 680 } 681#endif /* PFIL_HOOKS */ 682 683#ifdef ALTQ 684 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 685 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 686 /* packet dropped by traffic conditioner */ 687 return; 688 } 689#endif 690 691 /* 692 * Process options and, if not destined for us, 693 * ship it on. ip_dooptions returns 1 when an 694 * error was detected (causing an icmp message 695 * to be sent and the original packet to be freed). 696 */ 697 ip_nhops = 0; /* for source routed packets */ 698 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 699 return; 700 701 /* 702 * Enable a consistency check between the destination address 703 * and the arrival interface for a unicast packet (the RFC 1122 704 * strong ES model) if IP forwarding is disabled and the packet 705 * is not locally generated. 706 * 707 * XXX - Checking also should be disabled if the destination 708 * address is ipnat'ed to a different interface. 709 * 710 * XXX - Checking is incompatible with IP aliases added 711 * to the loopback interface instead of the interface where 712 * the packets are received. 713 * 714 * XXX - We need to add a per ifaddr flag for this so that 715 * we get finer grain control. 716 */ 717 checkif = ip_checkinterface && (ipforwarding == 0) && 718 (m->m_pkthdr.rcvif != NULL) && 719 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0); 720 721 /* 722 * Check our list of addresses, to see if the packet is for us. 723 * 724 * Traditional 4.4BSD did not consult IFF_UP at all. 725 * The behavior here is to treat addresses on !IFF_UP interface 726 * as not mine. 727 */ 728 downmatch = 0; 729 LIST_FOREACH(ia, &IN_IFADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 730 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) { 731 if (checkif && ia->ia_ifp != m->m_pkthdr.rcvif) 732 continue; 733 if ((ia->ia_ifp->if_flags & IFF_UP) != 0) 734 break; 735 else 736 downmatch++; 737 } 738 } 739 if (ia != NULL) 740 goto ours; 741 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 742 IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) { 743 if (ifa->ifa_addr->sa_family != AF_INET) 744 continue; 745 ia = ifatoia(ifa); 746 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 747 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 748 /* 749 * Look for all-0's host part (old broadcast addr), 750 * either for subnet or net. 751 */ 752 ip->ip_dst.s_addr == ia->ia_subnet || 753 ip->ip_dst.s_addr == ia->ia_net) 754 goto ours; 755 /* 756 * An interface with IP address zero accepts 757 * all packets that arrive on that interface. 758 */ 759 if (in_nullhost(ia->ia_addr.sin_addr)) 760 goto ours; 761 } 762 } 763 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 764 struct in_multi *inm; 765#ifdef MROUTING 766 extern struct socket *ip_mrouter; 767 768 if (ip_mrouter) { 769 /* 770 * If we are acting as a multicast router, all 771 * incoming multicast packets are passed to the 772 * kernel-level multicast forwarding function. 773 * The packet is returned (relatively) intact; if 774 * ip_mforward() returns a non-zero value, the packet 775 * must be discarded, else it may be accepted below. 776 * 777 * (The IP ident field is put in the same byte order 778 * as expected when ip_mforward() is called from 779 * ip_output().) 780 */ 781 if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) { 782 ipstat.ips_cantforward++; 783 m_freem(m); 784 return; 785 } 786 787 /* 788 * The process-level routing demon needs to receive 789 * all multicast IGMP packets, whether or not this 790 * host belongs to their destination groups. 791 */ 792 if (ip->ip_p == IPPROTO_IGMP) 793 goto ours; 794 ipstat.ips_forward++; 795 } 796#endif 797 /* 798 * See if we belong to the destination multicast group on the 799 * arrival interface. 800 */ 801 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 802 if (inm == NULL) { 803 ipstat.ips_cantforward++; 804 m_freem(m); 805 return; 806 } 807 goto ours; 808 } 809 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 810 in_nullhost(ip->ip_dst)) 811 goto ours; 812 813 /* 814 * Not for us; forward if possible and desirable. 815 */ 816 if (ipforwarding == 0) { 817 ipstat.ips_cantforward++; 818 m_freem(m); 819 } else { 820 /* 821 * If ip_dst matched any of my address on !IFF_UP interface, 822 * and there's no IFF_UP interface that matches ip_dst, 823 * send icmp unreach. Forwarding it will result in in-kernel 824 * forwarding loop till TTL goes to 0. 825 */ 826 if (downmatch) { 827 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 828 ipstat.ips_cantforward++; 829 return; 830 } 831#ifdef IPSEC 832 if (ipsec4_in_reject(m, NULL)) { 833 ipsecstat.in_polvio++; 834 goto bad; 835 } 836#endif 837#ifdef FAST_IPSEC 838 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 839 s = splsoftnet(); 840 if (mtag != NULL) { 841 tdbi = (struct tdb_ident *)(mtag + 1); 842 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 843 } else { 844 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 845 IP_FORWARDING, &error); 846 } 847 if (sp == NULL) { /* NB: can happen if error */ 848 splx(s); 849 /*XXX error stat???*/ 850 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 851 goto bad; 852 } 853 854 /* 855 * Check security policy against packet attributes. 856 */ 857 error = ipsec_in_reject(sp, m); 858 KEY_FREESP(&sp); 859 splx(s); 860 if (error) { 861 ipstat.ips_cantforward++; 862 goto bad; 863 } 864 865 /* 866 * Peek at the outbound SP for this packet to determine if 867 * it's a Fast Forward candidate. 868 */ 869 mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 870 if (mtag != NULL) 871 m->m_flags &= ~M_CANFASTFWD; 872 else { 873 s = splsoftnet(); 874 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, 875 (IP_FORWARDING | 876 (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 877 &error, NULL); 878 if (sp != NULL) { 879 m->m_flags &= ~M_CANFASTFWD; 880 KEY_FREESP(&sp); 881 } 882 splx(s); 883 } 884#endif /* FAST_IPSEC */ 885 886 ip_forward(m, srcrt); 887 } 888 return; 889 890ours: 891 /* 892 * If offset or IP_MF are set, must reassemble. 893 * Otherwise, nothing need be done. 894 * (We could look in the reassembly queue to see 895 * if the packet was previously fragmented, 896 * but it's not worth the time; just let them time out.) 897 */ 898 if (ip->ip_off & ~htons(IP_DF|IP_RF)) { 899 uint16_t off; 900 /* 901 * Prevent TCP blind data attacks by not allowing non-initial 902 * fragments to start at less than 68 bytes (minimal fragment 903 * size). 904 */ 905 off = htons(ip->ip_off) & ~(IP_DF|IP_EF|IP_MF); 906 if (off > 0 && off + hlen < IP_MINFRAGSIZE - 1) { 907 ipstat.ips_badfrags++; 908 goto bad; 909 } 910 /* 911 * Look for queue of fragments 912 * of this datagram. 913 */ 914 IPQ_LOCK(); 915 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 916 LIST_FOREACH(fp, &ipq[hash], ipq_q) { 917 if (ip->ip_id == fp->ipq_id && 918 in_hosteq(ip->ip_src, fp->ipq_src) && 919 in_hosteq(ip->ip_dst, fp->ipq_dst) && 920 ip->ip_p == fp->ipq_p) 921 goto found; 922 923 } 924 fp = 0; 925found: 926 927 /* 928 * Adjust ip_len to not reflect header, 929 * set ipqe_mff if more fragments are expected, 930 * convert offset of this to bytes. 931 */ 932 ip->ip_len = htons(ntohs(ip->ip_len) - hlen); 933 mff = (ip->ip_off & htons(IP_MF)) != 0; 934 if (mff) { 935 /* 936 * Make sure that fragments have a data length 937 * that's a non-zero multiple of 8 bytes. 938 */ 939 if (ntohs(ip->ip_len) == 0 || 940 (ntohs(ip->ip_len) & 0x7) != 0) { 941 ipstat.ips_badfrags++; 942 IPQ_UNLOCK(); 943 goto bad; 944 } 945 } 946 ip->ip_off = htons((ntohs(ip->ip_off) & IP_OFFMASK) << 3); 947 948 /* 949 * If datagram marked as having more fragments 950 * or if this is not the first fragment, 951 * attempt reassembly; if it succeeds, proceed. 952 */ 953 if (mff || ip->ip_off != htons(0)) { 954 ipstat.ips_fragments++; 955 s = splvm(); 956 ipqe = pool_get(&ipqent_pool, PR_NOWAIT); 957 splx(s); 958 if (ipqe == NULL) { 959 ipstat.ips_rcvmemdrop++; 960 IPQ_UNLOCK(); 961 goto bad; 962 } 963 ipqe->ipqe_mff = mff; 964 ipqe->ipqe_m = m; 965 ipqe->ipqe_ip = ip; 966 m = ip_reass(ipqe, fp, &ipq[hash]); 967 if (m == 0) { 968 IPQ_UNLOCK(); 969 return; 970 } 971 ipstat.ips_reassembled++; 972 ip = mtod(m, struct ip *); 973 hlen = ip->ip_hl << 2; 974 ip->ip_len = htons(ntohs(ip->ip_len) + hlen); 975 } else 976 if (fp) 977 ip_freef(fp); 978 IPQ_UNLOCK(); 979 } 980 981#if defined(IPSEC) 982 /* 983 * enforce IPsec policy checking if we are seeing last header. 984 * note that we do not visit this with protocols with pcb layer 985 * code - like udp/tcp/raw ip. 986 */ 987 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 988 ipsec4_in_reject(m, NULL)) { 989 ipsecstat.in_polvio++; 990 goto bad; 991 } 992#endif 993#ifdef FAST_IPSEC 994 /* 995 * enforce IPsec policy checking if we are seeing last header. 996 * note that we do not visit this with protocols with pcb layer 997 * code - like udp/tcp/raw ip. 998 */ 999 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 1000 /* 1001 * Check if the packet has already had IPsec processing 1002 * done. If so, then just pass it along. This tag gets 1003 * set during AH, ESP, etc. input handling, before the 1004 * packet is returned to the ip input queue for delivery. 1005 */ 1006 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 1007 s = splsoftnet(); 1008 if (mtag != NULL) { 1009 tdbi = (struct tdb_ident *)(mtag + 1); 1010 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 1011 } else { 1012 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 1013 IP_FORWARDING, &error); 1014 } 1015 if (sp != NULL) { 1016 /* 1017 * Check security policy against packet attributes. 1018 */ 1019 error = ipsec_in_reject(sp, m); 1020 KEY_FREESP(&sp); 1021 } else { 1022 /* XXX error stat??? */ 1023 error = EINVAL; 1024DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 1025 } 1026 splx(s); 1027 if (error) 1028 goto bad; 1029 } 1030#endif /* FAST_IPSEC */ 1031 1032 /* 1033 * Switch out to protocol's input routine. 1034 */ 1035#if IFA_STATS 1036 if (ia && ip) 1037 ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len); 1038#endif 1039 ipstat.ips_delivered++; 1040 { 1041 int off = hlen, nh = ip->ip_p; 1042 1043 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 1044 return; 1045 } 1046bad: 1047 m_freem(m); 1048 return; 1049 1050badcsum: 1051 ipstat.ips_badsum++; 1052 m_freem(m); 1053} 1054 1055/* 1056 * Take incoming datagram fragment and try to 1057 * reassemble it into whole datagram. If a chain for 1058 * reassembly of this datagram already exists, then it 1059 * is given as fp; otherwise have to make a chain. 1060 */ 1061struct mbuf * 1062ip_reass(struct ipqent *ipqe, struct ipq *fp, struct ipqhead *ipqhead) 1063{ 1064 struct mbuf *m = ipqe->ipqe_m; 1065 struct ipqent *nq, *p, *q; 1066 struct ip *ip; 1067 struct mbuf *t; 1068 int hlen = ipqe->ipqe_ip->ip_hl << 2; 1069 int i, next, s; 1070 1071 IPQ_LOCK_CHECK(); 1072 1073 /* 1074 * Presence of header sizes in mbufs 1075 * would confuse code below. 1076 */ 1077 m->m_data += hlen; 1078 m->m_len -= hlen; 1079 1080#ifdef notyet 1081 /* make sure fragment limit is up-to-date */ 1082 CHECK_NMBCLUSTER_PARAMS(); 1083 1084 /* If we have too many fragments, drop the older half. */ 1085 if (ip_nfrags >= ip_maxfrags) 1086 ip_reass_drophalf(void); 1087#endif 1088 1089 /* 1090 * We are about to add a fragment; increment frag count. 1091 */ 1092 ip_nfrags++; 1093 1094 /* 1095 * If first fragment to arrive, create a reassembly queue. 1096 */ 1097 if (fp == 0) { 1098 /* 1099 * Enforce upper bound on number of fragmented packets 1100 * for which we attempt reassembly; 1101 * If maxfrag is 0, never accept fragments. 1102 * If maxfrag is -1, accept all fragments without limitation. 1103 */ 1104 if (ip_maxfragpackets < 0) 1105 ; 1106 else if (ip_nfragpackets >= ip_maxfragpackets) 1107 goto dropfrag; 1108 ip_nfragpackets++; 1109 MALLOC(fp, struct ipq *, sizeof (struct ipq), 1110 M_FTABLE, M_NOWAIT); 1111 if (fp == NULL) 1112 goto dropfrag; 1113 LIST_INSERT_HEAD(ipqhead, fp, ipq_q); 1114 fp->ipq_nfrags = 1; 1115 fp->ipq_ttl = IPFRAGTTL; 1116 fp->ipq_p = ipqe->ipqe_ip->ip_p; 1117 fp->ipq_id = ipqe->ipqe_ip->ip_id; 1118 TAILQ_INIT(&fp->ipq_fragq); 1119 fp->ipq_src = ipqe->ipqe_ip->ip_src; 1120 fp->ipq_dst = ipqe->ipqe_ip->ip_dst; 1121 p = NULL; 1122 goto insert; 1123 } else { 1124 fp->ipq_nfrags++; 1125 } 1126 1127 /* 1128 * Find a segment which begins after this one does. 1129 */ 1130 for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; 1131 p = q, q = TAILQ_NEXT(q, ipqe_q)) 1132 if (ntohs(q->ipqe_ip->ip_off) > ntohs(ipqe->ipqe_ip->ip_off)) 1133 break; 1134 1135 /* 1136 * If there is a preceding segment, it may provide some of 1137 * our data already. If so, drop the data from the incoming 1138 * segment. If it provides all of our data, drop us. 1139 */ 1140 if (p != NULL) { 1141 i = ntohs(p->ipqe_ip->ip_off) + ntohs(p->ipqe_ip->ip_len) - 1142 ntohs(ipqe->ipqe_ip->ip_off); 1143 if (i > 0) { 1144 if (i >= ntohs(ipqe->ipqe_ip->ip_len)) 1145 goto dropfrag; 1146 m_adj(ipqe->ipqe_m, i); 1147 ipqe->ipqe_ip->ip_off = 1148 htons(ntohs(ipqe->ipqe_ip->ip_off) + i); 1149 ipqe->ipqe_ip->ip_len = 1150 htons(ntohs(ipqe->ipqe_ip->ip_len) - i); 1151 } 1152 } 1153 1154 /* 1155 * While we overlap succeeding segments trim them or, 1156 * if they are completely covered, dequeue them. 1157 */ 1158 for (; q != NULL && 1159 ntohs(ipqe->ipqe_ip->ip_off) + ntohs(ipqe->ipqe_ip->ip_len) > 1160 ntohs(q->ipqe_ip->ip_off); q = nq) { 1161 i = (ntohs(ipqe->ipqe_ip->ip_off) + 1162 ntohs(ipqe->ipqe_ip->ip_len)) - ntohs(q->ipqe_ip->ip_off); 1163 if (i < ntohs(q->ipqe_ip->ip_len)) { 1164 q->ipqe_ip->ip_len = 1165 htons(ntohs(q->ipqe_ip->ip_len) - i); 1166 q->ipqe_ip->ip_off = 1167 htons(ntohs(q->ipqe_ip->ip_off) + i); 1168 m_adj(q->ipqe_m, i); 1169 break; 1170 } 1171 nq = TAILQ_NEXT(q, ipqe_q); 1172 m_freem(q->ipqe_m); 1173 TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q); 1174 s = splvm(); 1175 pool_put(&ipqent_pool, q); 1176 splx(s); 1177 fp->ipq_nfrags--; 1178 ip_nfrags--; 1179 } 1180 1181insert: 1182 /* 1183 * Stick new segment in its place; 1184 * check for complete reassembly. 1185 */ 1186 if (p == NULL) { 1187 TAILQ_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); 1188 } else { 1189 TAILQ_INSERT_AFTER(&fp->ipq_fragq, p, ipqe, ipqe_q); 1190 } 1191 next = 0; 1192 for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; 1193 p = q, q = TAILQ_NEXT(q, ipqe_q)) { 1194 if (ntohs(q->ipqe_ip->ip_off) != next) 1195 return (0); 1196 next += ntohs(q->ipqe_ip->ip_len); 1197 } 1198 if (p->ipqe_mff) 1199 return (0); 1200 1201 /* 1202 * Reassembly is complete. Check for a bogus message size and 1203 * concatenate fragments. 1204 */ 1205 q = TAILQ_FIRST(&fp->ipq_fragq); 1206 ip = q->ipqe_ip; 1207 if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) { 1208 ipstat.ips_toolong++; 1209 ip_freef(fp); 1210 return (0); 1211 } 1212 m = q->ipqe_m; 1213 t = m->m_next; 1214 m->m_next = 0; 1215 m_cat(m, t); 1216 nq = TAILQ_NEXT(q, ipqe_q); 1217 s = splvm(); 1218 pool_put(&ipqent_pool, q); 1219 splx(s); 1220 for (q = nq; q != NULL; q = nq) { 1221 t = q->ipqe_m; 1222 nq = TAILQ_NEXT(q, ipqe_q); 1223 s = splvm(); 1224 pool_put(&ipqent_pool, q); 1225 splx(s); 1226 m_cat(m, t); 1227 } 1228 ip_nfrags -= fp->ipq_nfrags; 1229 1230 /* 1231 * Create header for new ip packet by 1232 * modifying header of first packet; 1233 * dequeue and discard fragment reassembly header. 1234 * Make header visible. 1235 */ 1236 ip->ip_len = htons(next); 1237 ip->ip_src = fp->ipq_src; 1238 ip->ip_dst = fp->ipq_dst; 1239 LIST_REMOVE(fp, ipq_q); 1240 FREE(fp, M_FTABLE); 1241 ip_nfragpackets--; 1242 m->m_len += (ip->ip_hl << 2); 1243 m->m_data -= (ip->ip_hl << 2); 1244 /* some debugging cruft by sklower, below, will go away soon */ 1245 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1246 int plen = 0; 1247 for (t = m; t; t = t->m_next) 1248 plen += t->m_len; 1249 m->m_pkthdr.len = plen; 1250 m->m_pkthdr.csum_flags = 0; 1251 } 1252 return (m); 1253 1254dropfrag: 1255 if (fp != 0) 1256 fp->ipq_nfrags--; 1257 ip_nfrags--; 1258 ipstat.ips_fragdropped++; 1259 m_freem(m); 1260 s = splvm(); 1261 pool_put(&ipqent_pool, ipqe); 1262 splx(s); 1263 return (0); 1264} 1265 1266/* 1267 * Free a fragment reassembly header and all 1268 * associated datagrams. 1269 */ 1270void 1271ip_freef(struct ipq *fp) 1272{ 1273 struct ipqent *q, *p; 1274 u_int nfrags = 0; 1275 int s; 1276 1277 IPQ_LOCK_CHECK(); 1278 1279 for (q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; q = p) { 1280 p = TAILQ_NEXT(q, ipqe_q); 1281 m_freem(q->ipqe_m); 1282 nfrags++; 1283 TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q); 1284 s = splvm(); 1285 pool_put(&ipqent_pool, q); 1286 splx(s); 1287 } 1288 1289 if (nfrags != fp->ipq_nfrags) 1290 printf("ip_freef: nfrags %d != %d\n", fp->ipq_nfrags, nfrags); 1291 ip_nfrags -= nfrags; 1292 LIST_REMOVE(fp, ipq_q); 1293 FREE(fp, M_FTABLE); 1294 ip_nfragpackets--; 1295} 1296 1297/* 1298 * IP reassembly TTL machinery for multiplicative drop. 1299 */ 1300static u_int fragttl_histo[(IPFRAGTTL+1)]; 1301 1302 1303/* 1304 * Decrement TTL of all reasembly queue entries by `ticks'. 1305 * Count number of distinct fragments (as opposed to partial, fragmented 1306 * datagrams) in the reassembly queue. While we traverse the entire 1307 * reassembly queue, compute and return the median TTL over all fragments. 1308 */ 1309static u_int 1310ip_reass_ttl_decr(u_int ticks) 1311{ 1312 u_int nfrags, median, dropfraction, keepfraction; 1313 struct ipq *fp, *nfp; 1314 int i; 1315 1316 nfrags = 0; 1317 memset(fragttl_histo, 0, sizeof fragttl_histo); 1318 1319 for (i = 0; i < IPREASS_NHASH; i++) { 1320 for (fp = LIST_FIRST(&ipq[i]); fp != NULL; fp = nfp) { 1321 fp->ipq_ttl = ((fp->ipq_ttl <= ticks) ? 1322 0 : fp->ipq_ttl - ticks); 1323 nfp = LIST_NEXT(fp, ipq_q); 1324 if (fp->ipq_ttl == 0) { 1325 ipstat.ips_fragtimeout++; 1326 ip_freef(fp); 1327 } else { 1328 nfrags += fp->ipq_nfrags; 1329 fragttl_histo[fp->ipq_ttl] += fp->ipq_nfrags; 1330 } 1331 } 1332 } 1333 1334 KASSERT(ip_nfrags == nfrags); 1335 1336 /* Find median (or other drop fraction) in histogram. */ 1337 dropfraction = (ip_nfrags / 2); 1338 keepfraction = ip_nfrags - dropfraction; 1339 for (i = IPFRAGTTL, median = 0; i >= 0; i--) { 1340 median += fragttl_histo[i]; 1341 if (median >= keepfraction) 1342 break; 1343 } 1344 1345 /* Return TTL of median (or other fraction). */ 1346 return (u_int)i; 1347} 1348 1349void 1350ip_reass_drophalf(void) 1351{ 1352 1353 u_int median_ticks; 1354 /* 1355 * Compute median TTL of all fragments, and count frags 1356 * with that TTL or lower (roughly half of all fragments). 1357 */ 1358 median_ticks = ip_reass_ttl_decr(0); 1359 1360 /* Drop half. */ 1361 median_ticks = ip_reass_ttl_decr(median_ticks); 1362 1363} 1364 1365/* 1366 * IP timer processing; 1367 * if a timer expires on a reassembly 1368 * queue, discard it. 1369 */ 1370void 1371ip_slowtimo(void) 1372{ 1373 static u_int dropscanidx = 0; 1374 u_int i; 1375 u_int median_ttl; 1376 int s = splsoftnet(); 1377 1378 IPQ_LOCK(); 1379 1380 /* Age TTL of all fragments by 1 tick .*/ 1381 median_ttl = ip_reass_ttl_decr(1); 1382 1383 /* make sure fragment limit is up-to-date */ 1384 CHECK_NMBCLUSTER_PARAMS(); 1385 1386 /* If we have too many fragments, drop the older half. */ 1387 if (ip_nfrags > ip_maxfrags) 1388 ip_reass_ttl_decr(median_ttl); 1389 1390 /* 1391 * If we are over the maximum number of fragmented packets 1392 * (due to the limit being lowered), drain off 1393 * enough to get down to the new limit. Start draining 1394 * from the reassembly hashqueue most recently drained. 1395 */ 1396 if (ip_maxfragpackets < 0) 1397 ; 1398 else { 1399 int wrapped = 0; 1400 1401 i = dropscanidx; 1402 while (ip_nfragpackets > ip_maxfragpackets && wrapped == 0) { 1403 while (LIST_FIRST(&ipq[i]) != NULL) 1404 ip_freef(LIST_FIRST(&ipq[i])); 1405 if (++i >= IPREASS_NHASH) { 1406 i = 0; 1407 } 1408 /* 1409 * Dont scan forever even if fragment counters are 1410 * wrong: stop after scanning entire reassembly queue. 1411 */ 1412 if (i == dropscanidx) 1413 wrapped = 1; 1414 } 1415 dropscanidx = i; 1416 } 1417 IPQ_UNLOCK(); 1418 splx(s); 1419} 1420 1421/* 1422 * Drain off all datagram fragments. 1423 */ 1424void 1425ip_drain(void) 1426{ 1427 1428 /* 1429 * We may be called from a device's interrupt context. If 1430 * the ipq is already busy, just bail out now. 1431 */ 1432 if (ipq_lock_try() == 0) 1433 return; 1434 1435 /* 1436 * Drop half the total fragments now. If more mbufs are needed, 1437 * we will be called again soon. 1438 */ 1439 ip_reass_drophalf(); 1440 1441 IPQ_UNLOCK(); 1442} 1443 1444/* 1445 * Do option processing on a datagram, 1446 * possibly discarding it if bad options are encountered, 1447 * or forwarding it if source-routed. 1448 * Returns 1 if packet has been forwarded/freed, 1449 * 0 if the packet should be processed further. 1450 */ 1451int 1452ip_dooptions(struct mbuf *m) 1453{ 1454 struct ip *ip = mtod(m, struct ip *); 1455 u_char *cp, *cp0; 1456 struct ip_timestamp *ipt; 1457 struct in_ifaddr *ia; 1458 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1459 struct in_addr dst; 1460 n_time ntime; 1461 1462 dst = ip->ip_dst; 1463 cp = (u_char *)(ip + 1); 1464 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1465 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1466 opt = cp[IPOPT_OPTVAL]; 1467 if (opt == IPOPT_EOL) 1468 break; 1469 if (opt == IPOPT_NOP) 1470 optlen = 1; 1471 else { 1472 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1473 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1474 goto bad; 1475 } 1476 optlen = cp[IPOPT_OLEN]; 1477 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1478 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1479 goto bad; 1480 } 1481 } 1482 switch (opt) { 1483 1484 default: 1485 break; 1486 1487 /* 1488 * Source routing with record. 1489 * Find interface with current destination address. 1490 * If none on this machine then drop if strictly routed, 1491 * or do nothing if loosely routed. 1492 * Record interface address and bring up next address 1493 * component. If strictly routed make sure next 1494 * address is on directly accessible net. 1495 */ 1496 case IPOPT_LSRR: 1497 case IPOPT_SSRR: 1498 if (ip_allowsrcrt == 0) { 1499 type = ICMP_UNREACH; 1500 code = ICMP_UNREACH_NET_PROHIB; 1501 goto bad; 1502 } 1503 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1504 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1505 goto bad; 1506 } 1507 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1508 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1509 goto bad; 1510 } 1511 ipaddr.sin_addr = ip->ip_dst; 1512 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); 1513 if (ia == 0) { 1514 if (opt == IPOPT_SSRR) { 1515 type = ICMP_UNREACH; 1516 code = ICMP_UNREACH_SRCFAIL; 1517 goto bad; 1518 } 1519 /* 1520 * Loose routing, and not at next destination 1521 * yet; nothing to do except forward. 1522 */ 1523 break; 1524 } 1525 off--; /* 0 origin */ 1526 if ((off + sizeof(struct in_addr)) > optlen) { 1527 /* 1528 * End of source route. Should be for us. 1529 */ 1530 save_rte(cp, ip->ip_src); 1531 break; 1532 } 1533 /* 1534 * locate outgoing interface 1535 */ 1536 bcopy((void *)(cp + off), (void *)&ipaddr.sin_addr, 1537 sizeof(ipaddr.sin_addr)); 1538 if (opt == IPOPT_SSRR) 1539 ia = ifatoia(ifa_ifwithladdr(sintosa(&ipaddr))); 1540 else 1541 ia = ip_rtaddr(ipaddr.sin_addr); 1542 if (ia == 0) { 1543 type = ICMP_UNREACH; 1544 code = ICMP_UNREACH_SRCFAIL; 1545 goto bad; 1546 } 1547 ip->ip_dst = ipaddr.sin_addr; 1548 bcopy((void *)&ia->ia_addr.sin_addr, 1549 (void *)(cp + off), sizeof(struct in_addr)); 1550 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1551 /* 1552 * Let ip_intr's mcast routing check handle mcast pkts 1553 */ 1554 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1555 break; 1556 1557 case IPOPT_RR: 1558 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1559 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1560 goto bad; 1561 } 1562 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1563 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1564 goto bad; 1565 } 1566 /* 1567 * If no space remains, ignore. 1568 */ 1569 off--; /* 0 origin */ 1570 if ((off + sizeof(struct in_addr)) > optlen) 1571 break; 1572 bcopy((void *)(&ip->ip_dst), (void *)&ipaddr.sin_addr, 1573 sizeof(ipaddr.sin_addr)); 1574 /* 1575 * locate outgoing interface; if we're the destination, 1576 * use the incoming interface (should be same). 1577 */ 1578 if ((ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)))) 1579 == NULL && 1580 (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) { 1581 type = ICMP_UNREACH; 1582 code = ICMP_UNREACH_HOST; 1583 goto bad; 1584 } 1585 bcopy((void *)&ia->ia_addr.sin_addr, 1586 (void *)(cp + off), sizeof(struct in_addr)); 1587 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1588 break; 1589 1590 case IPOPT_TS: 1591 code = cp - (u_char *)ip; 1592 ipt = (struct ip_timestamp *)cp; 1593 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1594 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1595 goto bad; 1596 } 1597 if (ipt->ipt_ptr < 5) { 1598 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1599 goto bad; 1600 } 1601 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) { 1602 if (++ipt->ipt_oflw == 0) { 1603 code = (u_char *)&ipt->ipt_ptr - 1604 (u_char *)ip; 1605 goto bad; 1606 } 1607 break; 1608 } 1609 cp0 = (cp + ipt->ipt_ptr - 1); 1610 switch (ipt->ipt_flg) { 1611 1612 case IPOPT_TS_TSONLY: 1613 break; 1614 1615 case IPOPT_TS_TSANDADDR: 1616 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1617 sizeof(struct in_addr) > ipt->ipt_len) { 1618 code = (u_char *)&ipt->ipt_ptr - 1619 (u_char *)ip; 1620 goto bad; 1621 } 1622 ipaddr.sin_addr = dst; 1623 ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr), 1624 m->m_pkthdr.rcvif)); 1625 if (ia == 0) 1626 continue; 1627 bcopy(&ia->ia_addr.sin_addr, 1628 cp0, sizeof(struct in_addr)); 1629 ipt->ipt_ptr += sizeof(struct in_addr); 1630 break; 1631 1632 case IPOPT_TS_PRESPEC: 1633 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1634 sizeof(struct in_addr) > ipt->ipt_len) { 1635 code = (u_char *)&ipt->ipt_ptr - 1636 (u_char *)ip; 1637 goto bad; 1638 } 1639 bcopy(cp0, &ipaddr.sin_addr, 1640 sizeof(struct in_addr)); 1641 if (ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))) 1642 == NULL) 1643 continue; 1644 ipt->ipt_ptr += sizeof(struct in_addr); 1645 break; 1646 1647 default: 1648 /* XXX can't take &ipt->ipt_flg */ 1649 code = (u_char *)&ipt->ipt_ptr - 1650 (u_char *)ip + 1; 1651 goto bad; 1652 } 1653 ntime = iptime(); 1654 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1655 memmove((char *)cp + ipt->ipt_ptr - 1, cp0, 1656 sizeof(n_time)); 1657 ipt->ipt_ptr += sizeof(n_time); 1658 } 1659 } 1660 if (forward) { 1661 if (ip_forwsrcrt == 0) { 1662 type = ICMP_UNREACH; 1663 code = ICMP_UNREACH_SRCFAIL; 1664 goto bad; 1665 } 1666 ip_forward(m, 1); 1667 return (1); 1668 } 1669 return (0); 1670bad: 1671 icmp_error(m, type, code, 0, 0); 1672 ipstat.ips_badoptions++; 1673 return (1); 1674} 1675 1676/* 1677 * Given address of next destination (final or next hop), 1678 * return internet address info of interface to be used to get there. 1679 */ 1680struct in_ifaddr * 1681ip_rtaddr(struct in_addr dst) 1682{ 1683 struct rtentry *rt; 1684 union { 1685 struct sockaddr dst; 1686 struct sockaddr_in dst4; 1687 } u; 1688 1689 sockaddr_in_init(&u.dst4, &dst, 0); 1690 1691 if ((rt = rtcache_lookup(&ipforward_rt, &u.dst)) == NULL) 1692 return NULL; 1693 1694 return ifatoia(rt->rt_ifa); 1695} 1696 1697/* 1698 * Save incoming source route for use in replies, 1699 * to be picked up later by ip_srcroute if the receiver is interested. 1700 */ 1701void 1702save_rte(u_char *option, struct in_addr dst) 1703{ 1704 unsigned olen; 1705 1706 olen = option[IPOPT_OLEN]; 1707#ifdef DIAGNOSTIC 1708 if (ipprintfs) 1709 printf("save_rte: olen %d\n", olen); 1710#endif /* 0 */ 1711 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1712 return; 1713 bcopy((void *)option, (void *)ip_srcrt.srcopt, olen); 1714 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1715 ip_srcrt.dst = dst; 1716} 1717 1718/* 1719 * Retrieve incoming source route for use in replies, 1720 * in the same form used by setsockopt. 1721 * The first hop is placed before the options, will be removed later. 1722 */ 1723struct mbuf * 1724ip_srcroute(void) 1725{ 1726 struct in_addr *p, *q; 1727 struct mbuf *m; 1728 1729 if (ip_nhops == 0) 1730 return NULL; 1731 m = m_get(M_DONTWAIT, MT_SOOPTS); 1732 if (m == 0) 1733 return NULL; 1734 1735 MCLAIM(m, &inetdomain.dom_mowner); 1736#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1737 1738 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1739 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1740 OPTSIZ; 1741#ifdef DIAGNOSTIC 1742 if (ipprintfs) 1743 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1744#endif 1745 1746 /* 1747 * First save first hop for return route 1748 */ 1749 p = &ip_srcrt.route[ip_nhops - 1]; 1750 *(mtod(m, struct in_addr *)) = *p--; 1751#ifdef DIAGNOSTIC 1752 if (ipprintfs) 1753 printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1754#endif 1755 1756 /* 1757 * Copy option fields and padding (nop) to mbuf. 1758 */ 1759 ip_srcrt.nop = IPOPT_NOP; 1760 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1761 memmove(mtod(m, char *) + sizeof(struct in_addr), &ip_srcrt.nop, 1762 OPTSIZ); 1763 q = (struct in_addr *)(mtod(m, char *) + 1764 sizeof(struct in_addr) + OPTSIZ); 1765#undef OPTSIZ 1766 /* 1767 * Record return path as an IP source route, 1768 * reversing the path (pointers are now aligned). 1769 */ 1770 while (p >= ip_srcrt.route) { 1771#ifdef DIAGNOSTIC 1772 if (ipprintfs) 1773 printf(" %x", ntohl(q->s_addr)); 1774#endif 1775 *q++ = *p--; 1776 } 1777 /* 1778 * Last hop goes to final destination. 1779 */ 1780 *q = ip_srcrt.dst; 1781#ifdef DIAGNOSTIC 1782 if (ipprintfs) 1783 printf(" %x\n", ntohl(q->s_addr)); 1784#endif 1785 return (m); 1786} 1787 1788const int inetctlerrmap[PRC_NCMDS] = { 1789 [PRC_MSGSIZE] = EMSGSIZE, 1790 [PRC_HOSTDEAD] = EHOSTDOWN, 1791 [PRC_HOSTUNREACH] = EHOSTUNREACH, 1792 [PRC_UNREACH_NET] = EHOSTUNREACH, 1793 [PRC_UNREACH_HOST] = EHOSTUNREACH, 1794 [PRC_UNREACH_PROTOCOL] = ECONNREFUSED, 1795 [PRC_UNREACH_PORT] = ECONNREFUSED, 1796 [PRC_UNREACH_SRCFAIL] = EHOSTUNREACH, 1797 [PRC_PARAMPROB] = ENOPROTOOPT, 1798}; 1799 1800/* 1801 * Forward a packet. If some error occurs return the sender 1802 * an icmp packet. Note we can't always generate a meaningful 1803 * icmp message because icmp doesn't have a large enough repertoire 1804 * of codes and types. 1805 * 1806 * If not forwarding, just drop the packet. This could be confusing 1807 * if ipforwarding was zero but some routing protocol was advancing 1808 * us as a gateway to somewhere. However, we must let the routing 1809 * protocol deal with that. 1810 * 1811 * The srcrt parameter indicates whether the packet is being forwarded 1812 * via a source route. 1813 */ 1814void 1815ip_forward(struct mbuf *m, int srcrt) 1816{ 1817 struct ip *ip = mtod(m, struct ip *); 1818 struct rtentry *rt; 1819 int error, type = 0, code = 0, destmtu = 0; 1820 struct mbuf *mcopy; 1821 n_long dest; 1822 union { 1823 struct sockaddr dst; 1824 struct sockaddr_in dst4; 1825 } u; 1826 1827 /* 1828 * We are now in the output path. 1829 */ 1830 MCLAIM(m, &ip_tx_mowner); 1831 1832 /* 1833 * Clear any in-bound checksum flags for this packet. 1834 */ 1835 m->m_pkthdr.csum_flags = 0; 1836 1837 dest = 0; 1838#ifdef DIAGNOSTIC 1839 if (ipprintfs) { 1840 printf("forward: src %s ", inet_ntoa(ip->ip_src)); 1841 printf("dst %s ttl %x\n", inet_ntoa(ip->ip_dst), ip->ip_ttl); 1842 } 1843#endif 1844 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1845 ipstat.ips_cantforward++; 1846 m_freem(m); 1847 return; 1848 } 1849 if (ip->ip_ttl <= IPTTLDEC) { 1850 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1851 return; 1852 } 1853 1854 sockaddr_in_init(&u.dst4, &ip->ip_dst, 0); 1855 if ((rt = rtcache_lookup(&ipforward_rt, &u.dst)) == NULL) { 1856 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0); 1857 return; 1858 } 1859 1860 /* 1861 * Save at most 68 bytes of the packet in case 1862 * we need to generate an ICMP message to the src. 1863 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1864 */ 1865 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1866 if (mcopy) 1867 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1868 1869 ip->ip_ttl -= IPTTLDEC; 1870 1871 /* 1872 * If forwarding packet using same interface that it came in on, 1873 * perhaps should send a redirect to sender to shortcut a hop. 1874 * Only send redirect if source is sending directly to us, 1875 * and if packet was not source routed (or has any options). 1876 * Also, don't send redirect if forwarding using a default route 1877 * or a route modified by a redirect. 1878 */ 1879 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1880 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1881 !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) && 1882 ipsendredirects && !srcrt) { 1883 if (rt->rt_ifa && 1884 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1885 ifatoia(rt->rt_ifa)->ia_subnet) { 1886 if (rt->rt_flags & RTF_GATEWAY) 1887 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1888 else 1889 dest = ip->ip_dst.s_addr; 1890 /* 1891 * Router requirements says to only send host 1892 * redirects. 1893 */ 1894 type = ICMP_REDIRECT; 1895 code = ICMP_REDIRECT_HOST; 1896#ifdef DIAGNOSTIC 1897 if (ipprintfs) 1898 printf("redirect (%d) to %x\n", code, 1899 (u_int32_t)dest); 1900#endif 1901 } 1902 } 1903 1904 error = ip_output(m, NULL, &ipforward_rt, 1905 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1906 (struct ip_moptions *)NULL, (struct socket *)NULL); 1907 1908 if (error) 1909 ipstat.ips_cantforward++; 1910 else { 1911 ipstat.ips_forward++; 1912 if (type) 1913 ipstat.ips_redirectsent++; 1914 else { 1915 if (mcopy) { 1916#ifdef GATEWAY 1917 if (mcopy->m_flags & M_CANFASTFWD) 1918 ipflow_create(&ipforward_rt, mcopy); 1919#endif 1920 m_freem(mcopy); 1921 } 1922 return; 1923 } 1924 } 1925 if (mcopy == NULL) 1926 return; 1927 1928 switch (error) { 1929 1930 case 0: /* forwarded, but need redirect */ 1931 /* type, code set above */ 1932 break; 1933 1934 case ENETUNREACH: /* shouldn't happen, checked above */ 1935 case EHOSTUNREACH: 1936 case ENETDOWN: 1937 case EHOSTDOWN: 1938 default: 1939 type = ICMP_UNREACH; 1940 code = ICMP_UNREACH_HOST; 1941 break; 1942 1943 case EMSGSIZE: 1944 type = ICMP_UNREACH; 1945 code = ICMP_UNREACH_NEEDFRAG; 1946#if !defined(IPSEC) && !defined(FAST_IPSEC) 1947 if ((rt = rtcache_getrt(&ipforward_rt)) != NULL) 1948 destmtu = rt->rt_ifp->if_mtu; 1949#else 1950 /* 1951 * If the packet is routed over IPsec tunnel, tell the 1952 * originator the tunnel MTU. 1953 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1954 * XXX quickhack!!! 1955 */ 1956 if ((rt = rtcache_getrt(&ipforward_rt)) != NULL) { 1957 struct secpolicy *sp; 1958 int ipsecerror; 1959 size_t ipsechdr; 1960 struct route *ro; 1961 1962 sp = ipsec4_getpolicybyaddr(mcopy, 1963 IPSEC_DIR_OUTBOUND, IP_FORWARDING, 1964 &ipsecerror); 1965 1966 if (sp == NULL) 1967 destmtu = rt->rt_ifp->if_mtu; 1968 else { 1969 /* count IPsec header size */ 1970 ipsechdr = ipsec4_hdrsiz(mcopy, 1971 IPSEC_DIR_OUTBOUND, NULL); 1972 1973 /* 1974 * find the correct route for outer IPv4 1975 * header, compute tunnel MTU. 1976 */ 1977 1978 if (sp->req != NULL 1979 && sp->req->sav != NULL 1980 && sp->req->sav->sah != NULL) { 1981 ro = &sp->req->sav->sah->sa_route; 1982 if (rt && rt->rt_ifp) { 1983 destmtu = 1984 rt->rt_rmx.rmx_mtu ? 1985 rt->rt_rmx.rmx_mtu : 1986 rt->rt_ifp->if_mtu; 1987 destmtu -= ipsechdr; 1988 } 1989 } 1990 1991#ifdef IPSEC 1992 key_freesp(sp); 1993#else 1994 KEY_FREESP(&sp); 1995#endif 1996 } 1997 } 1998#endif /*IPSEC*/ 1999 ipstat.ips_cantfrag++; 2000 break; 2001 2002 case ENOBUFS: 2003#if 1 2004 /* 2005 * a router should not generate ICMP_SOURCEQUENCH as 2006 * required in RFC1812 Requirements for IP Version 4 Routers. 2007 * source quench could be a big problem under DoS attacks, 2008 * or if the underlying interface is rate-limited. 2009 */ 2010 if (mcopy) 2011 m_freem(mcopy); 2012 return; 2013#else 2014 type = ICMP_SOURCEQUENCH; 2015 code = 0; 2016 break; 2017#endif 2018 } 2019 icmp_error(mcopy, type, code, dest, destmtu); 2020} 2021 2022void 2023ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2024 struct mbuf *m) 2025{ 2026 2027 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2028 struct timeval tv; 2029 2030 microtime(&tv); 2031 *mp = sbcreatecontrol((void *) &tv, sizeof(tv), 2032 SCM_TIMESTAMP, SOL_SOCKET); 2033 if (*mp) 2034 mp = &(*mp)->m_next; 2035 } 2036 if (inp->inp_flags & INP_RECVDSTADDR) { 2037 *mp = sbcreatecontrol((void *) &ip->ip_dst, 2038 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2039 if (*mp) 2040 mp = &(*mp)->m_next; 2041 } 2042#ifdef notyet 2043 /* 2044 * XXX 2045 * Moving these out of udp_input() made them even more broken 2046 * than they already were. 2047 * - fenner@parc.xerox.com 2048 */ 2049 /* options were tossed already */ 2050 if (inp->inp_flags & INP_RECVOPTS) { 2051 *mp = sbcreatecontrol((void *) opts_deleted_above, 2052 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2053 if (*mp) 2054 mp = &(*mp)->m_next; 2055 } 2056 /* ip_srcroute doesn't do what we want here, need to fix */ 2057 if (inp->inp_flags & INP_RECVRETOPTS) { 2058 *mp = sbcreatecontrol((void *) ip_srcroute(), 2059 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2060 if (*mp) 2061 mp = &(*mp)->m_next; 2062 } 2063#endif 2064 if (inp->inp_flags & INP_RECVIF) { 2065 struct sockaddr_dl sdl; 2066 2067 sockaddr_dl_init(&sdl, sizeof(sdl), 2068 (m->m_pkthdr.rcvif != NULL) 2069 ? m->m_pkthdr.rcvif->if_index 2070 : 0, 2071 0, NULL, 0, NULL, 0); 2072 *mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP); 2073 if (*mp) 2074 mp = &(*mp)->m_next; 2075 } 2076} 2077 2078/* 2079 * sysctl helper routine for net.inet.ip.forwsrcrt. 2080 */ 2081static int 2082sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS) 2083{ 2084 int error, tmp; 2085 struct sysctlnode node; 2086 2087 node = *rnode; 2088 tmp = ip_forwsrcrt; 2089 node.sysctl_data = &tmp; 2090 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 2091 if (error || newp == NULL) 2092 return (error); 2093 2094 if (kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT, 2095 0, NULL, NULL, NULL)) 2096 return (EPERM); 2097 2098 ip_forwsrcrt = tmp; 2099 2100 return (0); 2101} 2102 2103/* 2104 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the 2105 * range of the new value and tweaks timers if it changes. 2106 */ 2107static int 2108sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS) 2109{ 2110 int error, tmp; 2111 struct sysctlnode node; 2112 2113 node = *rnode; 2114 tmp = ip_mtudisc_timeout; 2115 node.sysctl_data = &tmp; 2116 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 2117 if (error || newp == NULL) 2118 return (error); 2119 if (tmp < 0) 2120 return (EINVAL); 2121 2122 ip_mtudisc_timeout = tmp; 2123 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout); 2124 2125 return (0); 2126} 2127 2128#ifdef GATEWAY 2129/* 2130 * sysctl helper routine for net.inet.ip.maxflows. 2131 */ 2132static int 2133sysctl_net_inet_ip_maxflows(SYSCTLFN_ARGS) 2134{ 2135 int s; 2136 2137 s = sysctl_lookup(SYSCTLFN_CALL(rnode)); 2138 if (s || newp == NULL) 2139 return (s); 2140 2141 s = splsoftnet(); 2142 ipflow_reap(0); 2143 splx(s); 2144 2145 return (0); 2146} 2147 2148static int 2149sysctl_net_inet_ip_hashsize(SYSCTLFN_ARGS) 2150{ 2151 int error, tmp; 2152 struct sysctlnode node; 2153 2154 node = *rnode; 2155 tmp = ip_hashsize; 2156 node.sysctl_data = &tmp; 2157 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 2158 if (error || newp == NULL) 2159 return (error); 2160 2161 if ((tmp & (tmp - 1)) == 0 && tmp != 0) { 2162 /* 2163 * Can only fail due to malloc() 2164 */ 2165 if (ipflow_invalidate_all(tmp)) 2166 return ENOMEM; 2167 } else { 2168 /* 2169 * EINVAL if not a power of 2 2170 */ 2171 return EINVAL; 2172 } 2173 2174 return (0); 2175} 2176#endif /* GATEWAY */ 2177 2178 2179SYSCTL_SETUP(sysctl_net_inet_ip_setup, "sysctl net.inet.ip subtree setup") 2180{ 2181 extern int subnetsarelocal, hostzeroisbroadcast; 2182 2183 sysctl_createv(clog, 0, NULL, NULL, 2184 CTLFLAG_PERMANENT, 2185 CTLTYPE_NODE, "net", NULL, 2186 NULL, 0, NULL, 0, 2187 CTL_NET, CTL_EOL); 2188 sysctl_createv(clog, 0, NULL, NULL, 2189 CTLFLAG_PERMANENT, 2190 CTLTYPE_NODE, "inet", 2191 SYSCTL_DESCR("PF_INET related settings"), 2192 NULL, 0, NULL, 0, 2193 CTL_NET, PF_INET, CTL_EOL); 2194 sysctl_createv(clog, 0, NULL, NULL, 2195 CTLFLAG_PERMANENT, 2196 CTLTYPE_NODE, "ip", 2197 SYSCTL_DESCR("IPv4 related settings"), 2198 NULL, 0, NULL, 0, 2199 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL); 2200 2201 sysctl_createv(clog, 0, NULL, NULL, 2202 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2203 CTLTYPE_INT, "forwarding", 2204 SYSCTL_DESCR("Enable forwarding of INET datagrams"), 2205 NULL, 0, &ipforwarding, 0, 2206 CTL_NET, PF_INET, IPPROTO_IP, 2207 IPCTL_FORWARDING, CTL_EOL); 2208 sysctl_createv(clog, 0, NULL, NULL, 2209 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2210 CTLTYPE_INT, "redirect", 2211 SYSCTL_DESCR("Enable sending of ICMP redirect messages"), 2212 NULL, 0, &ipsendredirects, 0, 2213 CTL_NET, PF_INET, IPPROTO_IP, 2214 IPCTL_SENDREDIRECTS, CTL_EOL); 2215 sysctl_createv(clog, 0, NULL, NULL, 2216 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2217 CTLTYPE_INT, "ttl", 2218 SYSCTL_DESCR("Default TTL for an INET datagram"), 2219 NULL, 0, &ip_defttl, 0, 2220 CTL_NET, PF_INET, IPPROTO_IP, 2221 IPCTL_DEFTTL, CTL_EOL); 2222#ifdef IPCTL_DEFMTU 2223 sysctl_createv(clog, 0, NULL, NULL, 2224 CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */, 2225 CTLTYPE_INT, "mtu", 2226 SYSCTL_DESCR("Default MTA for an INET route"), 2227 NULL, 0, &ip_mtu, 0, 2228 CTL_NET, PF_INET, IPPROTO_IP, 2229 IPCTL_DEFMTU, CTL_EOL); 2230#endif /* IPCTL_DEFMTU */ 2231 sysctl_createv(clog, 0, NULL, NULL, 2232 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2233 CTLTYPE_INT, "forwsrcrt", 2234 SYSCTL_DESCR("Enable forwarding of source-routed " 2235 "datagrams"), 2236 sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0, 2237 CTL_NET, PF_INET, IPPROTO_IP, 2238 IPCTL_FORWSRCRT, CTL_EOL); 2239 sysctl_createv(clog, 0, NULL, NULL, 2240 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2241 CTLTYPE_INT, "directed-broadcast", 2242 SYSCTL_DESCR("Enable forwarding of broadcast datagrams"), 2243 NULL, 0, &ip_directedbcast, 0, 2244 CTL_NET, PF_INET, IPPROTO_IP, 2245 IPCTL_DIRECTEDBCAST, CTL_EOL); 2246 sysctl_createv(clog, 0, NULL, NULL, 2247 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2248 CTLTYPE_INT, "allowsrcrt", 2249 SYSCTL_DESCR("Accept source-routed datagrams"), 2250 NULL, 0, &ip_allowsrcrt, 0, 2251 CTL_NET, PF_INET, IPPROTO_IP, 2252 IPCTL_ALLOWSRCRT, CTL_EOL); 2253 sysctl_createv(clog, 0, NULL, NULL, 2254 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2255 CTLTYPE_INT, "subnetsarelocal", 2256 SYSCTL_DESCR("Whether logical subnets are considered " 2257 "local"), 2258 NULL, 0, &subnetsarelocal, 0, 2259 CTL_NET, PF_INET, IPPROTO_IP, 2260 IPCTL_SUBNETSARELOCAL, CTL_EOL); 2261 sysctl_createv(clog, 0, NULL, NULL, 2262 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2263 CTLTYPE_INT, "mtudisc", 2264 SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"), 2265 NULL, 0, &ip_mtudisc, 0, 2266 CTL_NET, PF_INET, IPPROTO_IP, 2267 IPCTL_MTUDISC, CTL_EOL); 2268 sysctl_createv(clog, 0, NULL, NULL, 2269 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2270 CTLTYPE_INT, "anonportmin", 2271 SYSCTL_DESCR("Lowest ephemeral port number to assign"), 2272 sysctl_net_inet_ip_ports, 0, &anonportmin, 0, 2273 CTL_NET, PF_INET, IPPROTO_IP, 2274 IPCTL_ANONPORTMIN, CTL_EOL); 2275 sysctl_createv(clog, 0, NULL, NULL, 2276 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2277 CTLTYPE_INT, "anonportmax", 2278 SYSCTL_DESCR("Highest ephemeral port number to assign"), 2279 sysctl_net_inet_ip_ports, 0, &anonportmax, 0, 2280 CTL_NET, PF_INET, IPPROTO_IP, 2281 IPCTL_ANONPORTMAX, CTL_EOL); 2282 sysctl_createv(clog, 0, NULL, NULL, 2283 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2284 CTLTYPE_INT, "mtudisctimeout", 2285 SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"), 2286 sysctl_net_inet_ip_pmtudto, 0, &ip_mtudisc_timeout, 0, 2287 CTL_NET, PF_INET, IPPROTO_IP, 2288 IPCTL_MTUDISCTIMEOUT, CTL_EOL); 2289#ifdef GATEWAY 2290 sysctl_createv(clog, 0, NULL, NULL, 2291 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2292 CTLTYPE_INT, "maxflows", 2293 SYSCTL_DESCR("Number of flows for fast forwarding"), 2294 sysctl_net_inet_ip_maxflows, 0, &ip_maxflows, 0, 2295 CTL_NET, PF_INET, IPPROTO_IP, 2296 IPCTL_MAXFLOWS, CTL_EOL); 2297 sysctl_createv(clog, 0, NULL, NULL, 2298 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2299 CTLTYPE_INT, "hashsize", 2300 SYSCTL_DESCR("Size of hash table for fast forwarding (IPv4)"), 2301 sysctl_net_inet_ip_hashsize, 0, &ip_hashsize, 0, 2302 CTL_NET, PF_INET, IPPROTO_IP, 2303 CTL_CREATE, CTL_EOL); 2304#endif /* GATEWAY */ 2305 sysctl_createv(clog, 0, NULL, NULL, 2306 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2307 CTLTYPE_INT, "hostzerobroadcast", 2308 SYSCTL_DESCR("All zeroes address is broadcast address"), 2309 NULL, 0, &hostzeroisbroadcast, 0, 2310 CTL_NET, PF_INET, IPPROTO_IP, 2311 IPCTL_HOSTZEROBROADCAST, CTL_EOL); 2312#if NGIF > 0 2313 sysctl_createv(clog, 0, NULL, NULL, 2314 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2315 CTLTYPE_INT, "gifttl", 2316 SYSCTL_DESCR("Default TTL for a gif tunnel datagram"), 2317 NULL, 0, &ip_gif_ttl, 0, 2318 CTL_NET, PF_INET, IPPROTO_IP, 2319 IPCTL_GIF_TTL, CTL_EOL); 2320#endif /* NGIF */ 2321#ifndef IPNOPRIVPORTS 2322 sysctl_createv(clog, 0, NULL, NULL, 2323 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2324 CTLTYPE_INT, "lowportmin", 2325 SYSCTL_DESCR("Lowest privileged ephemeral port number " 2326 "to assign"), 2327 sysctl_net_inet_ip_ports, 0, &lowportmin, 0, 2328 CTL_NET, PF_INET, IPPROTO_IP, 2329 IPCTL_LOWPORTMIN, CTL_EOL); 2330 sysctl_createv(clog, 0, NULL, NULL, 2331 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2332 CTLTYPE_INT, "lowportmax", 2333 SYSCTL_DESCR("Highest privileged ephemeral port number " 2334 "to assign"), 2335 sysctl_net_inet_ip_ports, 0, &lowportmax, 0, 2336 CTL_NET, PF_INET, IPPROTO_IP, 2337 IPCTL_LOWPORTMAX, CTL_EOL); 2338#endif /* IPNOPRIVPORTS */ 2339 sysctl_createv(clog, 0, NULL, NULL, 2340 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2341 CTLTYPE_INT, "maxfragpackets", 2342 SYSCTL_DESCR("Maximum number of fragments to retain for " 2343 "possible reassembly"), 2344 NULL, 0, &ip_maxfragpackets, 0, 2345 CTL_NET, PF_INET, IPPROTO_IP, 2346 IPCTL_MAXFRAGPACKETS, CTL_EOL); 2347#if NGRE > 0 2348 sysctl_createv(clog, 0, NULL, NULL, 2349 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2350 CTLTYPE_INT, "grettl", 2351 SYSCTL_DESCR("Default TTL for a gre tunnel datagram"), 2352 NULL, 0, &ip_gre_ttl, 0, 2353 CTL_NET, PF_INET, IPPROTO_IP, 2354 IPCTL_GRE_TTL, CTL_EOL); 2355#endif /* NGRE */ 2356 sysctl_createv(clog, 0, NULL, NULL, 2357 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2358 CTLTYPE_INT, "checkinterface", 2359 SYSCTL_DESCR("Enable receive side of Strong ES model " 2360 "from RFC1122"), 2361 NULL, 0, &ip_checkinterface, 0, 2362 CTL_NET, PF_INET, IPPROTO_IP, 2363 IPCTL_CHECKINTERFACE, CTL_EOL); 2364 sysctl_createv(clog, 0, NULL, NULL, 2365 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2366 CTLTYPE_INT, "random_id", 2367 SYSCTL_DESCR("Assign random ip_id values"), 2368 NULL, 0, &ip_do_randomid, 0, 2369 CTL_NET, PF_INET, IPPROTO_IP, 2370 IPCTL_RANDOMID, CTL_EOL); 2371 sysctl_createv(clog, 0, NULL, NULL, 2372 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2373 CTLTYPE_INT, "do_loopback_cksum", 2374 SYSCTL_DESCR("Perform IP checksum on loopback"), 2375 NULL, 0, &ip_do_loopback_cksum, 0, 2376 CTL_NET, PF_INET, IPPROTO_IP, 2377 IPCTL_LOOPBACKCKSUM, CTL_EOL); 2378 sysctl_createv(clog, 0, NULL, NULL, 2379 CTLFLAG_PERMANENT, 2380 CTLTYPE_STRUCT, "stats", 2381 SYSCTL_DESCR("IP statistics"), 2382 NULL, 0, &ipstat, sizeof(ipstat), 2383 CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS, 2384 CTL_EOL); 2385} 2386