ip_input.c revision 1.401
1/* $NetBSD: ip_input.c,v 1.401 2021/03/08 18:03:25 christos 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 * 49 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 50 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 51 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 52 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 53 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 54 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 55 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 56 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 57 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 58 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 59 * POSSIBILITY OF SUCH DAMAGE. 60 */ 61 62/* 63 * Copyright (c) 1982, 1986, 1988, 1993 64 * The Regents of the University of California. All rights reserved. 65 * 66 * Redistribution and use in source and binary forms, with or without 67 * modification, are permitted provided that the following conditions 68 * are met: 69 * 1. Redistributions of source code must retain the above copyright 70 * notice, this list of conditions and the following disclaimer. 71 * 2. Redistributions in binary form must reproduce the above copyright 72 * notice, this list of conditions and the following disclaimer in the 73 * documentation and/or other materials provided with the distribution. 74 * 3. Neither the name of the University nor the names of its contributors 75 * may be used to endorse or promote products derived from this software 76 * without specific prior written permission. 77 * 78 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 79 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 80 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 81 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 82 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 83 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 84 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 85 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 86 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 87 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 88 * SUCH DAMAGE. 89 * 90 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 91 */ 92 93#include <sys/cdefs.h> 94__KERNEL_RCSID(0, "$NetBSD: ip_input.c,v 1.401 2021/03/08 18:03:25 christos Exp $"); 95 96#ifdef _KERNEL_OPT 97#include "opt_inet.h" 98#include "opt_gateway.h" 99#include "opt_ipsec.h" 100#include "opt_mrouting.h" 101#include "opt_mbuftrace.h" 102#include "opt_inet_csum.h" 103#include "opt_net_mpsafe.h" 104#endif 105 106#include "arp.h" 107 108#include <sys/param.h> 109#include <sys/systm.h> 110#include <sys/cpu.h> 111#include <sys/mbuf.h> 112#include <sys/domain.h> 113#include <sys/protosw.h> 114#include <sys/socket.h> 115#include <sys/socketvar.h> 116#include <sys/errno.h> 117#include <sys/time.h> 118#include <sys/kernel.h> 119#include <sys/pool.h> 120#include <sys/sysctl.h> 121#include <sys/kauth.h> 122 123#include <net/if.h> 124#include <net/if_dl.h> 125#include <net/route.h> 126#include <net/pktqueue.h> 127#include <net/pfil.h> 128 129#include <netinet/in.h> 130#include <netinet/in_systm.h> 131#include <netinet/ip.h> 132#include <netinet/in_pcb.h> 133#include <netinet/in_proto.h> 134#include <netinet/in_var.h> 135#include <netinet/ip_var.h> 136#include <netinet/ip_private.h> 137#include <netinet/ip_icmp.h> 138/* just for gif_ttl */ 139#include <netinet/in_gif.h> 140#include "gif.h" 141#include <net/if_gre.h> 142#include "gre.h" 143 144#ifdef MROUTING 145#include <netinet/ip_mroute.h> 146#endif 147#include <netinet/portalgo.h> 148 149#ifdef IPSEC 150#include <netipsec/ipsec.h> 151#endif 152 153#ifndef IPFORWARDING 154#ifdef GATEWAY 155#define IPFORWARDING 1 /* forward IP packets not for us */ 156#else 157#define IPFORWARDING 0 /* don't forward IP packets not for us */ 158#endif 159#endif 160 161#define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */ 162 163int ipforwarding = IPFORWARDING; 164int ipsendredirects = 1; 165int ip_defttl = IPDEFTTL; 166int ip_forwsrcrt = 0; 167int ip_directedbcast = 0; 168int ip_allowsrcrt = 0; 169int ip_mtudisc = 1; 170int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 171int ip_do_randomid = 1; 172 173/* 174 * XXX - Setting ip_checkinterface mostly implements the receive side of 175 * the Strong ES model described in RFC 1122, but since the routing table 176 * and transmit implementation do not implement the Strong ES model, 177 * setting this to 1 results in an odd hybrid. 178 * 179 * XXX - ip_checkinterface currently must be disabled if you use NAT 180 * to translate the destination address to another local interface. 181 * 182 * XXX - ip_checkinterface must be disabled if you add IP aliases 183 * to the loopback interface instead of the interface where the 184 * packets for those addresses are received. 185 */ 186static int ip_checkinterface __read_mostly = 0; 187 188struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 189 190pktqueue_t * ip_pktq __read_mostly; 191pfil_head_t * inet_pfil_hook __read_mostly; 192percpu_t * ipstat_percpu __read_mostly; 193 194static percpu_t *ipforward_rt_percpu __cacheline_aligned; 195 196uint16_t ip_id; 197 198#ifdef INET_CSUM_COUNTERS 199#include <sys/device.h> 200 201struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 202 NULL, "inet", "hwcsum bad"); 203struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 204 NULL, "inet", "hwcsum ok"); 205struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 206 NULL, "inet", "swcsum"); 207 208#define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 209 210EVCNT_ATTACH_STATIC(ip_hwcsum_bad); 211EVCNT_ATTACH_STATIC(ip_hwcsum_ok); 212EVCNT_ATTACH_STATIC(ip_swcsum); 213 214#else 215 216#define INET_CSUM_COUNTER_INCR(ev) /* nothing */ 217 218#endif /* INET_CSUM_COUNTERS */ 219 220/* 221 * Used to save the IP options in case a protocol wants to respond 222 * to an incoming packet over the same route if the packet got here 223 * using IP source routing. This allows connection establishment and 224 * maintenance when the remote end is on a network that is not known 225 * to us. 226 */ 227struct ip_srcrt { 228 int isr_nhops; /* number of hops */ 229 struct in_addr isr_dst; /* final destination */ 230 char isr_nop; /* one NOP to align */ 231 char isr_hdr[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN & OFFSET */ 232 struct in_addr isr_routes[MAX_IPOPTLEN/sizeof(struct in_addr)]; 233}; 234 235static int ip_drainwanted; 236 237static void save_rte(struct mbuf *, u_char *, struct in_addr); 238 239#ifdef MBUFTRACE 240struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx"); 241struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx"); 242#endif 243 244static void ipintr(void *); 245static void ip_input(struct mbuf *, struct ifnet *); 246static void ip_forward(struct mbuf *, int, struct ifnet *); 247static bool ip_dooptions(struct mbuf *); 248static struct in_ifaddr *ip_rtaddr(struct in_addr, struct psref *); 249static void sysctl_net_inet_ip_setup(struct sysctllog **); 250 251static struct in_ifaddr *ip_match_our_address(struct ifnet *, struct ip *, 252 int *); 253static struct in_ifaddr *ip_match_our_address_broadcast(struct ifnet *, 254 struct ip *); 255 256#ifdef NET_MPSAFE 257#define SOFTNET_LOCK() mutex_enter(softnet_lock) 258#define SOFTNET_UNLOCK() mutex_exit(softnet_lock) 259#else 260#define SOFTNET_LOCK() KASSERT(mutex_owned(softnet_lock)) 261#define SOFTNET_UNLOCK() KASSERT(mutex_owned(softnet_lock)) 262#endif 263 264/* 265 * IP initialization: fill in IP protocol switch table. 266 * All protocols not implemented in kernel go to raw IP protocol handler. 267 */ 268void 269ip_init(void) 270{ 271 const struct protosw *pr; 272 273 in_init(); 274 sysctl_net_inet_ip_setup(NULL); 275 276 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 277 KASSERT(pr != NULL); 278 279 ip_pktq = pktq_create(IFQ_MAXLEN, ipintr, NULL); 280 KASSERT(ip_pktq != NULL); 281 282 for (u_int i = 0; i < IPPROTO_MAX; i++) { 283 ip_protox[i] = pr - inetsw; 284 } 285 for (pr = inetdomain.dom_protosw; 286 pr < inetdomain.dom_protoswNPROTOSW; pr++) 287 if (pr->pr_domain->dom_family == PF_INET && 288 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 289 ip_protox[pr->pr_protocol] = pr - inetsw; 290 291 ip_reass_init(); 292 293 ip_id = time_uptime & 0xfffff; 294 295#ifdef GATEWAY 296 ipflow_init(); 297#endif 298 299 /* Register our Packet Filter hook. */ 300 inet_pfil_hook = pfil_head_create(PFIL_TYPE_AF, (void *)AF_INET); 301 KASSERT(inet_pfil_hook != NULL); 302 303#ifdef MBUFTRACE 304 MOWNER_ATTACH(&ip_tx_mowner); 305 MOWNER_ATTACH(&ip_rx_mowner); 306#endif 307 308 ipstat_percpu = percpu_alloc(sizeof(uint64_t) * IP_NSTATS); 309 ipforward_rt_percpu = rtcache_percpu_alloc(); 310 ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout); 311} 312 313static struct in_ifaddr * 314ip_match_our_address(struct ifnet *ifp, struct ip *ip, int *downmatch) 315{ 316 struct in_ifaddr *ia = NULL; 317 int checkif; 318 319 /* 320 * Enable a consistency check between the destination address 321 * and the arrival interface for a unicast packet (the RFC 1122 322 * strong ES model) if IP forwarding is disabled and the packet 323 * is not locally generated. 324 * 325 * XXX - We need to add a per ifaddr flag for this so that 326 * we get finer grain control. 327 */ 328 checkif = ip_checkinterface && (ipforwarding == 0) && 329 (ifp->if_flags & IFF_LOOPBACK) == 0; 330 331 IN_ADDRHASH_READER_FOREACH(ia, ip->ip_dst.s_addr) { 332 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) { 333 if (ia->ia4_flags & IN_IFF_NOTREADY) 334 continue; 335 if (checkif && ia->ia_ifp != ifp) 336 continue; 337 if ((ia->ia_ifp->if_flags & IFF_UP) == 0) { 338 (*downmatch)++; 339 continue; 340 } 341 if (ia->ia4_flags & IN_IFF_DETACHED && 342 (ifp->if_flags & IFF_LOOPBACK) == 0) 343 continue; 344 break; 345 } 346 } 347 348 return ia; 349} 350 351static struct in_ifaddr * 352ip_match_our_address_broadcast(struct ifnet *ifp, struct ip *ip) 353{ 354 struct in_ifaddr *ia = NULL; 355 struct ifaddr *ifa; 356 357 IFADDR_READER_FOREACH(ifa, ifp) { 358 if (ifa->ifa_addr->sa_family != AF_INET) 359 continue; 360 ia = ifatoia(ifa); 361 if (ia->ia4_flags & IN_IFF_NOTREADY) 362 continue; 363 if (ia->ia4_flags & IN_IFF_DETACHED && 364 (ifp->if_flags & IFF_LOOPBACK) == 0) 365 continue; 366 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 367 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 368 /* 369 * Look for all-0's host part (old broadcast addr), 370 * either for subnet or net. 371 */ 372 ip->ip_dst.s_addr == ia->ia_subnet || 373 ip->ip_dst.s_addr == ia->ia_net) 374 goto matched; 375 /* 376 * An interface with IP address zero accepts 377 * all packets that arrive on that interface. 378 */ 379 if (in_nullhost(ia->ia_addr.sin_addr)) 380 goto matched; 381 } 382 ia = NULL; 383 384matched: 385 return ia; 386} 387 388/* 389 * IP software interrupt routine. 390 */ 391static void 392ipintr(void *arg __unused) 393{ 394 struct mbuf *m; 395 396 KASSERT(cpu_softintr_p()); 397 398 SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE(); 399 while ((m = pktq_dequeue(ip_pktq)) != NULL) { 400 struct ifnet *ifp; 401 struct psref psref; 402 403 ifp = m_get_rcvif_psref(m, &psref); 404 if (__predict_false(ifp == NULL)) { 405 IP_STATINC(IP_STAT_IFDROP); 406 m_freem(m); 407 continue; 408 } 409 410 ip_input(m, ifp); 411 412 m_put_rcvif_psref(ifp, &psref); 413 } 414 SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE(); 415} 416 417/* 418 * IP input routine. Checksum and byte swap header. If fragmented 419 * try to reassemble. Process options. Pass to next level. 420 */ 421static void 422ip_input(struct mbuf *m, struct ifnet *ifp) 423{ 424 struct ip *ip = NULL; 425 struct in_ifaddr *ia = NULL; 426 int hlen = 0, len; 427 int downmatch; 428 int srcrt = 0; 429 int s; 430 431 KASSERTMSG(cpu_softintr_p(), "ip_input: not in the software " 432 "interrupt handler; synchronization assumptions violated"); 433 434 MCLAIM(m, &ip_rx_mowner); 435 KASSERT((m->m_flags & M_PKTHDR) != 0); 436 437 /* 438 * If no IP addresses have been set yet but the interfaces 439 * are receiving, can't do anything with incoming packets yet. 440 * Note: we pre-check without locks held. 441 */ 442 if (IN_ADDRLIST_READER_EMPTY()) { 443 IP_STATINC(IP_STAT_IFDROP); 444 goto out; 445 } 446 447 IP_STATINC(IP_STAT_TOTAL); 448 449 /* 450 * If the IP header is not aligned, slurp it up into a new 451 * mbuf with space for link headers, in the event we forward 452 * it. Otherwise, if it is aligned, make sure the entire 453 * base IP header is in the first mbuf of the chain. 454 */ 455 if (M_GET_ALIGNED_HDR(&m, struct ip, true) != 0) { 456 /* XXXJRT new stat, please */ 457 IP_STATINC(IP_STAT_TOOSMALL); 458 goto out; 459 } 460 ip = mtod(m, struct ip *); 461 if (ip->ip_v != IPVERSION) { 462 IP_STATINC(IP_STAT_BADVERS); 463 goto out; 464 } 465 hlen = ip->ip_hl << 2; 466 if (hlen < sizeof(struct ip)) { /* minimum header length */ 467 IP_STATINC(IP_STAT_BADHLEN); 468 goto out; 469 } 470 if (hlen > m->m_len) { 471 if ((m = m_pullup(m, hlen)) == NULL) { 472 IP_STATINC(IP_STAT_BADHLEN); 473 goto out; 474 } 475 ip = mtod(m, struct ip *); 476 } 477 478 /* 479 * RFC1122: packets with a multicast source address are 480 * not allowed. 481 */ 482 if (IN_MULTICAST(ip->ip_src.s_addr)) { 483 IP_STATINC(IP_STAT_BADADDR); 484 goto out; 485 } 486 487 /* 127/8 must not appear on wire - RFC1122 */ 488 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 489 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 490 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 491 IP_STATINC(IP_STAT_BADADDR); 492 goto out; 493 } 494 } 495 496 switch (m->m_pkthdr.csum_flags & 497 ((ifp->if_csum_flags_rx & M_CSUM_IPv4) | M_CSUM_IPv4_BAD)) { 498 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 499 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad); 500 IP_STATINC(IP_STAT_BADSUM); 501 goto out; 502 503 case M_CSUM_IPv4: 504 /* Checksum was okay. */ 505 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok); 506 break; 507 508 default: 509 /* 510 * Must compute it ourselves. Maybe skip checksum on 511 * loopback interfaces. 512 */ 513 if (__predict_true(!(ifp->if_flags & IFF_LOOPBACK) || 514 ip_do_loopback_cksum)) { 515 INET_CSUM_COUNTER_INCR(&ip_swcsum); 516 if (in_cksum(m, hlen) != 0) { 517 IP_STATINC(IP_STAT_BADSUM); 518 goto out; 519 } 520 } 521 break; 522 } 523 524 /* Retrieve the packet length. */ 525 len = ntohs(ip->ip_len); 526 527 /* 528 * Check for additional length bogosity 529 */ 530 if (len < hlen) { 531 IP_STATINC(IP_STAT_BADLEN); 532 goto out; 533 } 534 535 /* 536 * Check that the amount of data in the buffers is at least as much 537 * as the IP header would have us expect. Trim mbufs if longer than 538 * we expect. Drop packet if shorter than we expect. 539 */ 540 if (m->m_pkthdr.len < len) { 541 IP_STATINC(IP_STAT_TOOSHORT); 542 goto out; 543 } 544 if (m->m_pkthdr.len > len) { 545 if (m->m_len == m->m_pkthdr.len) { 546 m->m_len = len; 547 m->m_pkthdr.len = len; 548 } else 549 m_adj(m, len - m->m_pkthdr.len); 550 } 551 552 /* 553 * Assume that we can create a fast-forward IP flow entry 554 * based on this packet. 555 */ 556 m->m_flags |= M_CANFASTFWD; 557 558 /* 559 * Run through list of hooks for input packets. If there are any 560 * filters which require that additional packets in the flow are 561 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 562 * Note that filters must _never_ set this flag, as another filter 563 * in the list may have previously cleared it. 564 * 565 * Don't call hooks if the packet has already been processed by 566 * IPsec (encapsulated, tunnel mode). 567 */ 568#if defined(IPSEC) 569 if (!ipsec_used || !ipsec_skip_pfil(m)) 570#else 571 if (1) 572#endif 573 { 574 struct in_addr odst = ip->ip_dst; 575 bool freed; 576 577 freed = pfil_run_hooks(inet_pfil_hook, &m, ifp, PFIL_IN) != 0; 578 if (freed || m == NULL) { 579 m = NULL; 580 IP_STATINC(IP_STAT_PFILDROP_IN); 581 goto out; 582 } 583 if (__predict_false(m->m_len < sizeof(struct ip))) { 584 if ((m = m_pullup(m, sizeof(struct ip))) == NULL) { 585 IP_STATINC(IP_STAT_TOOSMALL); 586 goto out; 587 } 588 } 589 ip = mtod(m, struct ip *); 590 hlen = ip->ip_hl << 2; 591 if (hlen < sizeof(struct ip)) { /* minimum header length */ 592 IP_STATINC(IP_STAT_BADHLEN); 593 goto out; 594 } 595 if (hlen > m->m_len) { 596 if ((m = m_pullup(m, hlen)) == NULL) { 597 IP_STATINC(IP_STAT_BADHLEN); 598 goto out; 599 } 600 ip = mtod(m, struct ip *); 601 } 602 603 /* 604 * XXX The setting of "srcrt" here is to prevent ip_forward() 605 * from generating ICMP redirects for packets that have 606 * been redirected by a hook back out on to the same LAN that 607 * they came from and is not an indication that the packet 608 * is being influenced by source routing options. This 609 * allows things like 610 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp" 611 * where tlp0 is both on the 1.1.1.0/24 network and is the 612 * default route for hosts on 1.1.1.0/24. Of course this 613 * also requires a "map tlp0 ..." to complete the story. 614 * One might argue whether or not this kind of network config. 615 * should be supported in this manner... 616 */ 617 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 618 } 619 620#ifdef ALTQ 621 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 622 if (altq_input) { 623 SOFTNET_LOCK(); 624 if ((*altq_input)(m, AF_INET) == 0) { 625 /* Packet dropped by traffic conditioner. */ 626 SOFTNET_UNLOCK(); 627 m = NULL; 628 goto out; 629 } 630 SOFTNET_UNLOCK(); 631 } 632#endif 633 634 /* 635 * Process options and, if not destined for us, 636 * ship it on. ip_dooptions returns 1 when an 637 * error was detected (causing an icmp message 638 * to be sent and the original packet to be freed). 639 */ 640 if (hlen > sizeof(struct ip) && ip_dooptions(m)) { 641 m = NULL; 642 goto out; 643 } 644 645 /* 646 * Check our list of addresses, to see if the packet is for us. 647 * 648 * Traditional 4.4BSD did not consult IFF_UP at all. 649 * The behavior here is to treat addresses on !IFF_UP interface 650 * or IN_IFF_NOTREADY addresses as not mine. 651 */ 652 downmatch = 0; 653 s = pserialize_read_enter(); 654 ia = ip_match_our_address(ifp, ip, &downmatch); 655 if (ia != NULL) { 656 pserialize_read_exit(s); 657 goto ours; 658 } 659 660 if (ifp->if_flags & IFF_BROADCAST) { 661 ia = ip_match_our_address_broadcast(ifp, ip); 662 if (ia != NULL) { 663 pserialize_read_exit(s); 664 goto ours; 665 } 666 } 667 pserialize_read_exit(s); 668 669 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 670#ifdef MROUTING 671 extern struct socket *ip_mrouter; 672 673 if (ip_mrouter) { 674 /* 675 * If we are acting as a multicast router, all 676 * incoming multicast packets are passed to the 677 * kernel-level multicast forwarding function. 678 * The packet is returned (relatively) intact; if 679 * ip_mforward() returns a non-zero value, the packet 680 * must be discarded, else it may be accepted below. 681 * 682 * (The IP ident field is put in the same byte order 683 * as expected when ip_mforward() is called from 684 * ip_output().) 685 */ 686 SOFTNET_LOCK(); 687 if (ip_mforward(m, ifp) != 0) { 688 SOFTNET_UNLOCK(); 689 IP_STATINC(IP_STAT_CANTFORWARD); 690 goto out; 691 } 692 SOFTNET_UNLOCK(); 693 694 /* 695 * The process-level routing demon needs to receive 696 * all multicast IGMP packets, whether or not this 697 * host belongs to their destination groups. 698 */ 699 if (ip->ip_p == IPPROTO_IGMP) { 700 goto ours; 701 } 702 IP_STATINC(IP_STAT_CANTFORWARD); 703 } 704#endif 705 /* 706 * See if we belong to the destination multicast group on the 707 * arrival interface. 708 */ 709 if (!in_multi_group(ip->ip_dst, ifp, 0)) { 710 IP_STATINC(IP_STAT_CANTFORWARD); 711 goto out; 712 } 713 goto ours; 714 } 715 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 716 in_nullhost(ip->ip_dst)) 717 goto ours; 718 719 /* 720 * Not for us; forward if possible and desirable. 721 */ 722 if (ipforwarding == 0) { 723 IP_STATINC(IP_STAT_CANTFORWARD); 724 m_freem(m); 725 } else { 726 /* 727 * If ip_dst matched any of my address on !IFF_UP interface, 728 * and there's no IFF_UP interface that matches ip_dst, 729 * send icmp unreach. Forwarding it will result in in-kernel 730 * forwarding loop till TTL goes to 0. 731 */ 732 if (downmatch) { 733 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 734 IP_STATINC(IP_STAT_CANTFORWARD); 735 return; 736 } 737#ifdef IPSEC 738 /* Check the security policy (SP) for the packet */ 739 if (ipsec_used) { 740 if (ipsec_ip_input_checkpolicy(m, true) != 0) { 741 IP_STATINC(IP_STAT_IPSECDROP_IN); 742 goto out; 743 } 744 } 745#endif 746 ip_forward(m, srcrt, ifp); 747 } 748 return; 749 750ours: 751 /* 752 * If offset or IP_MF are set, must reassemble. 753 */ 754 if (ip->ip_off & ~htons(IP_DF|IP_RF)) { 755 /* 756 * Pass to IP reassembly mechanism. 757 */ 758 if (ip_reass_packet(&m) != 0) { 759 /* Failed; invalid fragment(s) or packet. */ 760 goto out; 761 } 762 if (m == NULL) { 763 /* More fragments should come; silently return. */ 764 goto out; 765 } 766 /* 767 * Reassembly is done, we have the final packet. 768 * Update cached data in local variable(s). 769 */ 770 ip = mtod(m, struct ip *); 771 hlen = ip->ip_hl << 2; 772 } 773 774 M_VERIFY_PACKET(m); 775 776#ifdef IPSEC 777 /* 778 * Enforce IPsec policy checking if we are seeing last header. 779 * Note that we do not visit this with protocols with PCB layer 780 * code - like UDP/TCP/raw IP. 781 */ 782 if (ipsec_used && 783 (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 784 if (ipsec_ip_input_checkpolicy(m, false) != 0) { 785 IP_STATINC(IP_STAT_IPSECDROP_IN); 786 goto out; 787 } 788 } 789#endif 790 791 /* 792 * Switch out to protocol's input routine. 793 */ 794#if IFA_STATS 795 if (ia) { 796 struct in_ifaddr *_ia; 797 /* 798 * Keep a reference from ip_match_our_address with psref 799 * is expensive, so explore ia here again. 800 */ 801 s = pserialize_read_enter(); 802 _ia = in_get_ia(ip->ip_dst); 803 _ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len); 804 pserialize_read_exit(s); 805 } 806#endif 807 IP_STATINC(IP_STAT_DELIVERED); 808 809 const int off = hlen, nh = ip->ip_p; 810 811 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 812 return; 813 814out: 815 if (m != NULL) 816 m_freem(m); 817} 818 819/* 820 * IP timer processing. 821 */ 822void 823ip_slowtimo(void) 824{ 825 826 SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE(); 827 828 ip_reass_slowtimo(); 829 830 SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE(); 831} 832 833/* 834 * IP drain processing. 835 */ 836void 837ip_drain(void) 838{ 839 840 KERNEL_LOCK(1, NULL); 841 ip_reass_drain(); 842 KERNEL_UNLOCK_ONE(NULL); 843} 844 845/* 846 * ip_dooptions: perform option processing on a datagram, possibly discarding 847 * it if bad options are encountered, or forwarding it if source-routed. 848 * 849 * => Returns true if packet has been forwarded/freed. 850 * => Returns false if the packet should be processed further. 851 */ 852static bool 853ip_dooptions(struct mbuf *m) 854{ 855 struct ip *ip = mtod(m, struct ip *); 856 u_char *cp, *cp0; 857 struct ip_timestamp *ipt; 858 struct in_ifaddr *ia; 859 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 860 int srr_present, rr_present, ts_present; 861 struct in_addr dst; 862 n_time ntime; 863 struct ifaddr *ifa = NULL; 864 int s; 865 866 srr_present = 0; 867 rr_present = 0; 868 ts_present = 0; 869 870 dst = ip->ip_dst; 871 cp = (u_char *)(ip + 1); 872 cnt = (ip->ip_hl << 2) - sizeof(struct ip); 873 for (; cnt > 0; cnt -= optlen, cp += optlen) { 874 opt = cp[IPOPT_OPTVAL]; 875 if (opt == IPOPT_EOL) 876 break; 877 if (opt == IPOPT_NOP) 878 optlen = 1; 879 else { 880 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 881 code = &cp[IPOPT_OLEN] - (u_char *)ip; 882 goto bad; 883 } 884 optlen = cp[IPOPT_OLEN]; 885 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 886 code = &cp[IPOPT_OLEN] - (u_char *)ip; 887 goto bad; 888 } 889 } 890 switch (opt) { 891 892 default: 893 break; 894 895 /* 896 * Source routing with record. 897 * Find interface with current destination address. 898 * If none on this machine then drop if strictly routed, 899 * or do nothing if loosely routed. 900 * Record interface address and bring up next address 901 * component. If strictly routed make sure next 902 * address is on directly accessible net. 903 */ 904 case IPOPT_LSRR: 905 case IPOPT_SSRR: { 906 struct psref psref; 907 struct sockaddr_in ipaddr = { 908 .sin_len = sizeof(ipaddr), 909 .sin_family = AF_INET, 910 }; 911 912 if (ip_allowsrcrt == 0) { 913 type = ICMP_UNREACH; 914 code = ICMP_UNREACH_NET_PROHIB; 915 goto bad; 916 } 917 if (srr_present++) { 918 code = &cp[IPOPT_OPTVAL] - (u_char *)ip; 919 goto bad; 920 } 921 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 922 code = &cp[IPOPT_OLEN] - (u_char *)ip; 923 goto bad; 924 } 925 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 926 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 927 goto bad; 928 } 929 ipaddr.sin_addr = ip->ip_dst; 930 931 s = pserialize_read_enter(); 932 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 933 if (ifa == NULL) { 934 pserialize_read_exit(s); 935 if (opt == IPOPT_SSRR) { 936 type = ICMP_UNREACH; 937 code = ICMP_UNREACH_SRCFAIL; 938 goto bad; 939 } 940 /* 941 * Loose routing, and not at next destination 942 * yet; nothing to do except forward. 943 */ 944 break; 945 } 946 pserialize_read_exit(s); 947 948 off--; /* 0 origin */ 949 if ((off + sizeof(struct in_addr)) > optlen) { 950 /* 951 * End of source route. Should be for us. 952 */ 953 save_rte(m, cp, ip->ip_src); 954 break; 955 } 956 /* 957 * locate outgoing interface 958 */ 959 memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off), 960 sizeof(ipaddr.sin_addr)); 961 if (opt == IPOPT_SSRR) { 962 ifa = ifa_ifwithladdr_psref(sintosa(&ipaddr), 963 &psref); 964 if (ifa != NULL) 965 ia = ifatoia(ifa); 966 else 967 ia = NULL; 968 } else { 969 ia = ip_rtaddr(ipaddr.sin_addr, &psref); 970 } 971 if (ia == NULL) { 972 type = ICMP_UNREACH; 973 code = ICMP_UNREACH_SRCFAIL; 974 goto bad; 975 } 976 ip->ip_dst = ipaddr.sin_addr; 977 memcpy(cp + off, &ia->ia_addr.sin_addr, 978 sizeof(struct in_addr)); 979 ia4_release(ia, &psref); 980 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 981 /* 982 * Let ip_intr's mcast routing check handle mcast pkts 983 */ 984 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 985 break; 986 } 987 988 case IPOPT_RR: { 989 struct psref psref; 990 struct sockaddr_in ipaddr = { 991 .sin_len = sizeof(ipaddr), 992 .sin_family = AF_INET, 993 }; 994 995 if (rr_present++) { 996 code = &cp[IPOPT_OPTVAL] - (u_char *)ip; 997 goto bad; 998 } 999 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1000 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1001 goto bad; 1002 } 1003 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1004 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1005 goto bad; 1006 } 1007 /* 1008 * If no space remains, ignore. 1009 */ 1010 off--; /* 0 origin */ 1011 if ((off + sizeof(struct in_addr)) > optlen) 1012 break; 1013 memcpy((void *)&ipaddr.sin_addr, (void *)&ip->ip_dst, 1014 sizeof(ipaddr.sin_addr)); 1015 /* 1016 * locate outgoing interface; if we're the destination, 1017 * use the incoming interface (should be same). 1018 */ 1019 ifa = ifa_ifwithaddr_psref(sintosa(&ipaddr), &psref); 1020 if (ifa == NULL) { 1021 ia = ip_rtaddr(ipaddr.sin_addr, &psref); 1022 if (ia == NULL) { 1023 type = ICMP_UNREACH; 1024 code = ICMP_UNREACH_HOST; 1025 goto bad; 1026 } 1027 } else { 1028 ia = ifatoia(ifa); 1029 } 1030 memcpy(cp + off, &ia->ia_addr.sin_addr, 1031 sizeof(struct in_addr)); 1032 ia4_release(ia, &psref); 1033 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1034 break; 1035 } 1036 1037 case IPOPT_TS: 1038 code = cp - (u_char *)ip; 1039 ipt = (struct ip_timestamp *)cp; 1040 if (ts_present++) { 1041 code = &cp[IPOPT_OPTVAL] - (u_char *)ip; 1042 goto bad; 1043 } 1044 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1045 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1046 goto bad; 1047 } 1048 if (ipt->ipt_ptr < 5) { 1049 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1050 goto bad; 1051 } 1052 if (ipt->ipt_ptr > ipt->ipt_len - sizeof(int32_t)) { 1053 if (++ipt->ipt_oflw == 0) { 1054 code = (u_char *)&ipt->ipt_ptr - 1055 (u_char *)ip; 1056 goto bad; 1057 } 1058 break; 1059 } 1060 cp0 = (cp + ipt->ipt_ptr - 1); 1061 switch (ipt->ipt_flg) { 1062 1063 case IPOPT_TS_TSONLY: 1064 break; 1065 1066 case IPOPT_TS_TSANDADDR: { 1067 struct ifnet *rcvif; 1068 int _s, _ss; 1069 struct sockaddr_in ipaddr = { 1070 .sin_len = sizeof(ipaddr), 1071 .sin_family = AF_INET, 1072 }; 1073 1074 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1075 sizeof(struct in_addr) > ipt->ipt_len) { 1076 code = (u_char *)&ipt->ipt_ptr - 1077 (u_char *)ip; 1078 goto bad; 1079 } 1080 ipaddr.sin_addr = dst; 1081 _ss = pserialize_read_enter(); 1082 rcvif = m_get_rcvif(m, &_s); 1083 if (__predict_true(rcvif != NULL)) { 1084 ifa = ifaof_ifpforaddr(sintosa(&ipaddr), 1085 rcvif); 1086 } 1087 m_put_rcvif(rcvif, &_s); 1088 if (ifa == NULL) { 1089 pserialize_read_exit(_ss); 1090 break; 1091 } 1092 ia = ifatoia(ifa); 1093 memcpy(cp0, &ia->ia_addr.sin_addr, 1094 sizeof(struct in_addr)); 1095 pserialize_read_exit(_ss); 1096 ipt->ipt_ptr += sizeof(struct in_addr); 1097 break; 1098 } 1099 1100 case IPOPT_TS_PRESPEC: { 1101 struct sockaddr_in ipaddr = { 1102 .sin_len = sizeof(ipaddr), 1103 .sin_family = AF_INET, 1104 }; 1105 1106 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1107 sizeof(struct in_addr) > ipt->ipt_len) { 1108 code = (u_char *)&ipt->ipt_ptr - 1109 (u_char *)ip; 1110 goto bad; 1111 } 1112 memcpy(&ipaddr.sin_addr, cp0, 1113 sizeof(struct in_addr)); 1114 s = pserialize_read_enter(); 1115 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 1116 if (ifa == NULL) { 1117 pserialize_read_exit(s); 1118 continue; 1119 } 1120 pserialize_read_exit(s); 1121 ipt->ipt_ptr += sizeof(struct in_addr); 1122 break; 1123 } 1124 1125 default: 1126 /* XXX can't take &ipt->ipt_flg */ 1127 code = (u_char *)&ipt->ipt_ptr - 1128 (u_char *)ip + 1; 1129 goto bad; 1130 } 1131 ntime = iptime(); 1132 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1133 memmove((char *)cp + ipt->ipt_ptr - 1, cp0, 1134 sizeof(n_time)); 1135 ipt->ipt_ptr += sizeof(n_time); 1136 } 1137 } 1138 if (forward) { 1139 struct ifnet *rcvif; 1140 struct psref _psref; 1141 1142 if (ip_forwsrcrt == 0) { 1143 type = ICMP_UNREACH; 1144 code = ICMP_UNREACH_SRCFAIL; 1145 goto bad; 1146 } 1147 1148 rcvif = m_get_rcvif_psref(m, &_psref); 1149 if (__predict_false(rcvif == NULL)) { 1150 type = ICMP_UNREACH; 1151 code = ICMP_UNREACH_HOST; 1152 goto bad; 1153 } 1154 ip_forward(m, 1, rcvif); 1155 m_put_rcvif_psref(rcvif, &_psref); 1156 return true; 1157 } 1158 return false; 1159bad: 1160 icmp_error(m, type, code, 0, 0); 1161 IP_STATINC(IP_STAT_BADOPTIONS); 1162 return true; 1163} 1164 1165/* 1166 * ip_rtaddr: given address of next destination (final or next hop), 1167 * return internet address info of interface to be used to get there. 1168 */ 1169static struct in_ifaddr * 1170ip_rtaddr(struct in_addr dst, struct psref *psref) 1171{ 1172 struct rtentry *rt; 1173 union { 1174 struct sockaddr dst; 1175 struct sockaddr_in dst4; 1176 } u; 1177 struct route *ro; 1178 1179 sockaddr_in_init(&u.dst4, &dst, 0); 1180 1181 ro = rtcache_percpu_getref(ipforward_rt_percpu); 1182 rt = rtcache_lookup(ro, &u.dst); 1183 if (rt == NULL) { 1184 rtcache_percpu_putref(ipforward_rt_percpu); 1185 return NULL; 1186 } 1187 1188 ia4_acquire(ifatoia(rt->rt_ifa), psref); 1189 rtcache_unref(rt, ro); 1190 rtcache_percpu_putref(ipforward_rt_percpu); 1191 1192 return ifatoia(rt->rt_ifa); 1193} 1194 1195/* 1196 * save_rte: save incoming source route for use in replies, to be picked 1197 * up later by ip_srcroute if the receiver is interested. 1198 */ 1199static void 1200save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1201{ 1202 struct ip_srcrt *isr; 1203 struct m_tag *mtag; 1204 unsigned olen; 1205 1206 olen = option[IPOPT_OLEN]; 1207 if (olen > sizeof(isr->isr_hdr) + sizeof(isr->isr_routes)) 1208 return; 1209 1210 mtag = m_tag_get(PACKET_TAG_SRCROUTE, sizeof(*isr), M_NOWAIT); 1211 if (mtag == NULL) 1212 return; 1213 isr = (struct ip_srcrt *)(mtag + 1); 1214 1215 memcpy(isr->isr_hdr, option, olen); 1216 isr->isr_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1217 isr->isr_dst = dst; 1218 m_tag_prepend(m, mtag); 1219} 1220 1221/* 1222 * Retrieve incoming source route for use in replies, 1223 * in the same form used by setsockopt. 1224 * The first hop is placed before the options, will be removed later. 1225 */ 1226struct mbuf * 1227ip_srcroute(struct mbuf *m0) 1228{ 1229 struct in_addr *p, *q; 1230 struct mbuf *m; 1231 struct ip_srcrt *isr; 1232 struct m_tag *mtag; 1233 1234 mtag = m_tag_find(m0, PACKET_TAG_SRCROUTE); 1235 if (mtag == NULL) 1236 return NULL; 1237 isr = (struct ip_srcrt *)(mtag + 1); 1238 1239 if (isr->isr_nhops == 0) 1240 return NULL; 1241 1242 m = m_get(M_DONTWAIT, MT_SOOPTS); 1243 if (m == NULL) 1244 return NULL; 1245 1246 MCLAIM(m, &inetdomain.dom_mowner); 1247#define OPTSIZ (sizeof(isr->isr_nop) + sizeof(isr->isr_hdr)) 1248 1249 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + header) */ 1250 m->m_len = (isr->isr_nhops + 1) * sizeof(struct in_addr) + OPTSIZ; 1251 1252 /* 1253 * First save first hop for return route 1254 */ 1255 p = &(isr->isr_routes[isr->isr_nhops - 1]); 1256 *(mtod(m, struct in_addr *)) = *p--; 1257 1258 /* 1259 * Copy option fields and padding (nop) to mbuf. 1260 */ 1261 isr->isr_nop = IPOPT_NOP; 1262 isr->isr_hdr[IPOPT_OFFSET] = IPOPT_MINOFF; 1263 memmove(mtod(m, char *) + sizeof(struct in_addr), &isr->isr_nop, 1264 OPTSIZ); 1265 q = (struct in_addr *)(mtod(m, char *) + 1266 sizeof(struct in_addr) + OPTSIZ); 1267#undef OPTSIZ 1268 /* 1269 * Record return path as an IP source route, 1270 * reversing the path (pointers are now aligned). 1271 */ 1272 while (p >= isr->isr_routes) { 1273 *q++ = *p--; 1274 } 1275 /* 1276 * Last hop goes to final destination. 1277 */ 1278 *q = isr->isr_dst; 1279 m_tag_delete(m0, mtag); 1280 return m; 1281} 1282 1283const int inetctlerrmap[PRC_NCMDS] = { 1284 [PRC_MSGSIZE] = EMSGSIZE, 1285 [PRC_HOSTDEAD] = EHOSTDOWN, 1286 [PRC_HOSTUNREACH] = EHOSTUNREACH, 1287 [PRC_UNREACH_NET] = EHOSTUNREACH, 1288 [PRC_UNREACH_HOST] = EHOSTUNREACH, 1289 [PRC_UNREACH_PROTOCOL] = ECONNREFUSED, 1290 [PRC_UNREACH_PORT] = ECONNREFUSED, 1291 [PRC_UNREACH_SRCFAIL] = EHOSTUNREACH, 1292 [PRC_PARAMPROB] = ENOPROTOOPT, 1293}; 1294 1295void 1296ip_fasttimo(void) 1297{ 1298 if (ip_drainwanted) { 1299 ip_drain(); 1300 ip_drainwanted = 0; 1301 } 1302} 1303 1304void 1305ip_drainstub(void) 1306{ 1307 ip_drainwanted = 1; 1308} 1309 1310/* 1311 * Forward a packet. If some error occurs return the sender 1312 * an icmp packet. Note we can't always generate a meaningful 1313 * icmp message because icmp doesn't have a large enough repertoire 1314 * of codes and types. 1315 * 1316 * If not forwarding, just drop the packet. This could be confusing 1317 * if ipforwarding was zero but some routing protocol was advancing 1318 * us as a gateway to somewhere. However, we must let the routing 1319 * protocol deal with that. 1320 * 1321 * The srcrt parameter indicates whether the packet is being forwarded 1322 * via a source route. 1323 */ 1324static void 1325ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif) 1326{ 1327 struct ip *ip = mtod(m, struct ip *); 1328 struct rtentry *rt; 1329 int error, type = 0, code = 0, destmtu = 0; 1330 struct mbuf *mcopy; 1331 n_long dest; 1332 union { 1333 struct sockaddr dst; 1334 struct sockaddr_in dst4; 1335 } u; 1336 uint64_t *ips; 1337 struct route *ro; 1338 1339 KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software " 1340 "interrupt handler; synchronization assumptions violated"); 1341 1342 /* 1343 * We are now in the output path. 1344 */ 1345 MCLAIM(m, &ip_tx_mowner); 1346 1347 /* 1348 * Clear any in-bound checksum flags for this packet. 1349 */ 1350 m->m_pkthdr.csum_flags = 0; 1351 1352 dest = 0; 1353 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1354 IP_STATINC(IP_STAT_CANTFORWARD); 1355 m_freem(m); 1356 return; 1357 } 1358 1359 if (ip->ip_ttl <= IPTTLDEC) { 1360 IP_STATINC(IP_STAT_TIMXCEED); 1361 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1362 return; 1363 } 1364 1365 sockaddr_in_init(&u.dst4, &ip->ip_dst, 0); 1366 1367 ro = rtcache_percpu_getref(ipforward_rt_percpu); 1368 rt = rtcache_lookup(ro, &u.dst); 1369 if (rt == NULL) { 1370 rtcache_percpu_putref(ipforward_rt_percpu); 1371 IP_STATINC(IP_STAT_NOROUTE); 1372 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0); 1373 return; 1374 } 1375 1376 /* 1377 * Save at most 68 bytes of the packet in case 1378 * we need to generate an ICMP message to the src. 1379 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1380 */ 1381 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1382 if (mcopy) 1383 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1384 1385 ip->ip_ttl -= IPTTLDEC; 1386 1387 /* 1388 * If forwarding packet using same interface that it came in on, 1389 * perhaps should send a redirect to sender to shortcut a hop. 1390 * Only send redirect if source is sending directly to us, 1391 * and if packet was not source routed (or has any options). 1392 * Also, don't send redirect if forwarding using a default route 1393 * or a route modified by a redirect. 1394 */ 1395 if (rt->rt_ifp == rcvif && 1396 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1397 !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) && 1398 ipsendredirects && !srcrt) { 1399 if ((ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1400 ifatoia(rt->rt_ifa)->ia_subnet) { 1401 if (rt->rt_flags & RTF_GATEWAY) 1402 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1403 else 1404 dest = ip->ip_dst.s_addr; 1405 /* 1406 * Router requirements says to only send host 1407 * redirects. 1408 */ 1409 type = ICMP_REDIRECT; 1410 code = ICMP_REDIRECT_HOST; 1411 } 1412 } 1413 rtcache_unref(rt, ro); 1414 1415 error = ip_output(m, NULL, ro, 1416 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1417 NULL, NULL); 1418 1419 if (error) { 1420 IP_STATINC(IP_STAT_CANTFORWARD); 1421 goto error; 1422 } 1423 1424 ips = IP_STAT_GETREF(); 1425 ips[IP_STAT_FORWARD]++; 1426 1427 if (type) { 1428 ips[IP_STAT_REDIRECTSENT]++; 1429 IP_STAT_PUTREF(); 1430 goto redirect; 1431 } 1432 1433 IP_STAT_PUTREF(); 1434 if (mcopy) { 1435#ifdef GATEWAY 1436 if (mcopy->m_flags & M_CANFASTFWD) 1437 ipflow_create(ro, mcopy); 1438#endif 1439 m_freem(mcopy); 1440 } 1441 1442 rtcache_percpu_putref(ipforward_rt_percpu); 1443 return; 1444 1445redirect: 1446error: 1447 if (mcopy == NULL) { 1448 rtcache_percpu_putref(ipforward_rt_percpu); 1449 return; 1450 } 1451 1452 switch (error) { 1453 1454 case 0: /* forwarded, but need redirect */ 1455 /* type, code set above */ 1456 break; 1457 1458 case ENETUNREACH: /* shouldn't happen, checked above */ 1459 case EHOSTUNREACH: 1460 case ENETDOWN: 1461 case EHOSTDOWN: 1462 default: 1463 type = ICMP_UNREACH; 1464 code = ICMP_UNREACH_HOST; 1465 break; 1466 1467 case EMSGSIZE: 1468 type = ICMP_UNREACH; 1469 code = ICMP_UNREACH_NEEDFRAG; 1470 1471 if ((rt = rtcache_validate(ro)) != NULL) { 1472 destmtu = rt->rt_ifp->if_mtu; 1473 rtcache_unref(rt, ro); 1474 } 1475#ifdef IPSEC 1476 if (ipsec_used) 1477 ipsec_mtu(mcopy, &destmtu); 1478#endif 1479 IP_STATINC(IP_STAT_CANTFRAG); 1480 break; 1481 1482 case ENOBUFS: 1483 /* 1484 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812, 1485 * Requirements for IP Version 4 Routers. Source quench can 1486 * be a big problem under DoS attacks or if the underlying 1487 * interface is rate-limited. 1488 */ 1489 if (mcopy) 1490 m_freem(mcopy); 1491 rtcache_percpu_putref(ipforward_rt_percpu); 1492 return; 1493 } 1494 icmp_error(mcopy, type, code, dest, destmtu); 1495 rtcache_percpu_putref(ipforward_rt_percpu); 1496} 1497 1498void 1499ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1500 struct mbuf *m) 1501{ 1502 struct socket *so = inp->inp_socket; 1503 int inpflags = inp->inp_flags; 1504 1505 if (SOOPT_TIMESTAMP(so->so_options)) 1506 mp = sbsavetimestamp(so->so_options, mp); 1507 1508 if (inpflags & INP_RECVDSTADDR) { 1509 *mp = sbcreatecontrol(&ip->ip_dst, 1510 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1511 if (*mp) 1512 mp = &(*mp)->m_next; 1513 } 1514 1515 if (inpflags & INP_RECVTTL) { 1516 *mp = sbcreatecontrol(&ip->ip_ttl, 1517 sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP); 1518 if (*mp) 1519 mp = &(*mp)->m_next; 1520 } 1521 1522 struct psref psref; 1523 ifnet_t *ifp = m_get_rcvif_psref(m, &psref); 1524 if (__predict_false(ifp == NULL)) { 1525#ifdef DIAGNOSTIC 1526 printf("%s: missing receive interface\n", __func__); 1527#endif 1528 return; /* XXX should report error? */ 1529 } 1530 1531 if (inpflags & INP_RECVPKTINFO) { 1532 struct in_pktinfo ipi; 1533 ipi.ipi_addr = ip->ip_dst; 1534 ipi.ipi_ifindex = ifp->if_index; 1535 *mp = sbcreatecontrol(&ipi, 1536 sizeof(ipi), IP_PKTINFO, IPPROTO_IP); 1537 if (*mp) 1538 mp = &(*mp)->m_next; 1539 } 1540 if (inpflags & INP_RECVIF) { 1541 struct sockaddr_dl sdl; 1542 1543 sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0, 1544 NULL, 0); 1545 *mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP); 1546 if (*mp) 1547 mp = &(*mp)->m_next; 1548 } 1549 m_put_rcvif_psref(ifp, &psref); 1550} 1551 1552/* 1553 * sysctl helper routine for net.inet.ip.forwsrcrt. 1554 */ 1555static int 1556sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS) 1557{ 1558 int error, tmp; 1559 struct sysctlnode node; 1560 1561 node = *rnode; 1562 tmp = ip_forwsrcrt; 1563 node.sysctl_data = &tmp; 1564 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1565 if (error || newp == NULL) 1566 return (error); 1567 1568 error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT, 1569 0, NULL, NULL, NULL); 1570 if (error) 1571 return (error); 1572 1573 ip_forwsrcrt = tmp; 1574 1575 return (0); 1576} 1577 1578/* 1579 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the 1580 * range of the new value and tweaks timers if it changes. 1581 */ 1582static int 1583sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS) 1584{ 1585 int error, tmp; 1586 struct sysctlnode node; 1587 1588 icmp_mtudisc_lock(); 1589 1590 node = *rnode; 1591 tmp = ip_mtudisc_timeout; 1592 node.sysctl_data = &tmp; 1593 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1594 if (error || newp == NULL) 1595 goto out; 1596 if (tmp < 0) { 1597 error = EINVAL; 1598 goto out; 1599 } 1600 1601 ip_mtudisc_timeout = tmp; 1602 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout); 1603 error = 0; 1604out: 1605 icmp_mtudisc_unlock(); 1606 return error; 1607} 1608 1609static int 1610sysctl_net_inet_ip_stats(SYSCTLFN_ARGS) 1611{ 1612 1613 return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS)); 1614} 1615 1616static void 1617sysctl_net_inet_ip_setup(struct sysctllog **clog) 1618{ 1619 sysctl_createv(clog, 0, NULL, NULL, 1620 CTLFLAG_PERMANENT, 1621 CTLTYPE_NODE, "inet", 1622 SYSCTL_DESCR("PF_INET related settings"), 1623 NULL, 0, NULL, 0, 1624 CTL_NET, PF_INET, CTL_EOL); 1625 sysctl_createv(clog, 0, NULL, NULL, 1626 CTLFLAG_PERMANENT, 1627 CTLTYPE_NODE, "ip", 1628 SYSCTL_DESCR("IPv4 related settings"), 1629 NULL, 0, NULL, 0, 1630 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL); 1631 1632 sysctl_createv(clog, 0, NULL, NULL, 1633 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1634 CTLTYPE_INT, "forwarding", 1635 SYSCTL_DESCR("Enable forwarding of INET datagrams"), 1636 NULL, 0, &ipforwarding, 0, 1637 CTL_NET, PF_INET, IPPROTO_IP, 1638 IPCTL_FORWARDING, CTL_EOL); 1639 sysctl_createv(clog, 0, NULL, NULL, 1640 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1641 CTLTYPE_INT, "redirect", 1642 SYSCTL_DESCR("Enable sending of ICMP redirect messages"), 1643 NULL, 0, &ipsendredirects, 0, 1644 CTL_NET, PF_INET, IPPROTO_IP, 1645 IPCTL_SENDREDIRECTS, CTL_EOL); 1646 sysctl_createv(clog, 0, NULL, NULL, 1647 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1648 CTLTYPE_INT, "ttl", 1649 SYSCTL_DESCR("Default TTL for an INET datagram"), 1650 NULL, 0, &ip_defttl, 0, 1651 CTL_NET, PF_INET, IPPROTO_IP, 1652 IPCTL_DEFTTL, CTL_EOL); 1653 sysctl_createv(clog, 0, NULL, NULL, 1654 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1655 CTLTYPE_INT, "forwsrcrt", 1656 SYSCTL_DESCR("Enable forwarding of source-routed " 1657 "datagrams"), 1658 sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0, 1659 CTL_NET, PF_INET, IPPROTO_IP, 1660 IPCTL_FORWSRCRT, CTL_EOL); 1661 sysctl_createv(clog, 0, NULL, NULL, 1662 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1663 CTLTYPE_INT, "directed-broadcast", 1664 SYSCTL_DESCR("Enable forwarding of broadcast datagrams"), 1665 NULL, 0, &ip_directedbcast, 0, 1666 CTL_NET, PF_INET, IPPROTO_IP, 1667 IPCTL_DIRECTEDBCAST, CTL_EOL); 1668 sysctl_createv(clog, 0, NULL, NULL, 1669 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1670 CTLTYPE_INT, "allowsrcrt", 1671 SYSCTL_DESCR("Accept source-routed datagrams"), 1672 NULL, 0, &ip_allowsrcrt, 0, 1673 CTL_NET, PF_INET, IPPROTO_IP, 1674 IPCTL_ALLOWSRCRT, CTL_EOL); 1675 1676 sysctl_createv(clog, 0, NULL, NULL, 1677 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1678 CTLTYPE_INT, "mtudisc", 1679 SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"), 1680 NULL, 0, &ip_mtudisc, 0, 1681 CTL_NET, PF_INET, IPPROTO_IP, 1682 IPCTL_MTUDISC, CTL_EOL); 1683 sysctl_createv(clog, 0, NULL, NULL, 1684 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1685 CTLTYPE_INT, "anonportmin", 1686 SYSCTL_DESCR("Lowest ephemeral port number to assign"), 1687 sysctl_net_inet_ip_ports, 0, &anonportmin, 0, 1688 CTL_NET, PF_INET, IPPROTO_IP, 1689 IPCTL_ANONPORTMIN, CTL_EOL); 1690 sysctl_createv(clog, 0, NULL, NULL, 1691 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1692 CTLTYPE_INT, "anonportmax", 1693 SYSCTL_DESCR("Highest ephemeral port number to assign"), 1694 sysctl_net_inet_ip_ports, 0, &anonportmax, 0, 1695 CTL_NET, PF_INET, IPPROTO_IP, 1696 IPCTL_ANONPORTMAX, CTL_EOL); 1697 sysctl_createv(clog, 0, NULL, NULL, 1698 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1699 CTLTYPE_INT, "mtudisctimeout", 1700 SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"), 1701 sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0, 1702 CTL_NET, PF_INET, IPPROTO_IP, 1703 IPCTL_MTUDISCTIMEOUT, CTL_EOL); 1704#ifndef IPNOPRIVPORTS 1705 sysctl_createv(clog, 0, NULL, NULL, 1706 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1707 CTLTYPE_INT, "lowportmin", 1708 SYSCTL_DESCR("Lowest privileged ephemeral port number " 1709 "to assign"), 1710 sysctl_net_inet_ip_ports, 0, &lowportmin, 0, 1711 CTL_NET, PF_INET, IPPROTO_IP, 1712 IPCTL_LOWPORTMIN, CTL_EOL); 1713 sysctl_createv(clog, 0, NULL, NULL, 1714 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1715 CTLTYPE_INT, "lowportmax", 1716 SYSCTL_DESCR("Highest privileged ephemeral port number " 1717 "to assign"), 1718 sysctl_net_inet_ip_ports, 0, &lowportmax, 0, 1719 CTL_NET, PF_INET, IPPROTO_IP, 1720 IPCTL_LOWPORTMAX, CTL_EOL); 1721#endif /* IPNOPRIVPORTS */ 1722#if NGRE > 0 1723 sysctl_createv(clog, 0, NULL, NULL, 1724 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1725 CTLTYPE_INT, "grettl", 1726 SYSCTL_DESCR("Default TTL for a gre tunnel datagram"), 1727 NULL, 0, &ip_gre_ttl, 0, 1728 CTL_NET, PF_INET, IPPROTO_IP, 1729 IPCTL_GRE_TTL, CTL_EOL); 1730#endif /* NGRE */ 1731 sysctl_createv(clog, 0, NULL, NULL, 1732 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1733 CTLTYPE_INT, "checkinterface", 1734 SYSCTL_DESCR("Enable receive side of Strong ES model " 1735 "from RFC1122"), 1736 NULL, 0, &ip_checkinterface, 0, 1737 CTL_NET, PF_INET, IPPROTO_IP, 1738 IPCTL_CHECKINTERFACE, CTL_EOL); 1739 sysctl_createv(clog, 0, NULL, NULL, 1740 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1741 CTLTYPE_INT, "random_id", 1742 SYSCTL_DESCR("Assign random ip_id values"), 1743 NULL, 0, &ip_do_randomid, 0, 1744 CTL_NET, PF_INET, IPPROTO_IP, 1745 IPCTL_RANDOMID, CTL_EOL); 1746 sysctl_createv(clog, 0, NULL, NULL, 1747 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1748 CTLTYPE_INT, "do_loopback_cksum", 1749 SYSCTL_DESCR("Perform IP checksum on loopback"), 1750 NULL, 0, &ip_do_loopback_cksum, 0, 1751 CTL_NET, PF_INET, IPPROTO_IP, 1752 IPCTL_LOOPBACKCKSUM, CTL_EOL); 1753 sysctl_createv(clog, 0, NULL, NULL, 1754 CTLFLAG_PERMANENT, 1755 CTLTYPE_STRUCT, "stats", 1756 SYSCTL_DESCR("IP statistics"), 1757 sysctl_net_inet_ip_stats, 0, NULL, 0, 1758 CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS, 1759 CTL_EOL); 1760#if NARP 1761 sysctl_createv(clog, 0, NULL, NULL, 1762 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1763 CTLTYPE_INT, "dad_count", 1764 SYSCTL_DESCR("Number of Duplicate Address Detection " 1765 "probes to send"), 1766 NULL, 0, &ip_dad_count, 0, 1767 CTL_NET, PF_INET, IPPROTO_IP, 1768 IPCTL_DAD_COUNT, CTL_EOL); 1769#endif 1770 1771 /* anonportalgo RFC6056 subtree */ 1772 const struct sysctlnode *portalgo_node; 1773 sysctl_createv(clog, 0, NULL, &portalgo_node, 1774 CTLFLAG_PERMANENT, 1775 CTLTYPE_NODE, "anonportalgo", 1776 SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"), 1777 NULL, 0, NULL, 0, 1778 CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL); 1779 sysctl_createv(clog, 0, &portalgo_node, NULL, 1780 CTLFLAG_PERMANENT, 1781 CTLTYPE_STRING, "available", 1782 SYSCTL_DESCR("available algorithms"), 1783 sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN, 1784 CTL_CREATE, CTL_EOL); 1785 sysctl_createv(clog, 0, &portalgo_node, NULL, 1786 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1787 CTLTYPE_STRING, "selected", 1788 SYSCTL_DESCR("selected algorithm"), 1789 sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN, 1790 CTL_CREATE, CTL_EOL); 1791 sysctl_createv(clog, 0, &portalgo_node, NULL, 1792 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1793 CTLTYPE_STRUCT, "reserve", 1794 SYSCTL_DESCR("bitmap of reserved ports"), 1795 sysctl_portalgo_reserve4, 0, NULL, 0, 1796 CTL_CREATE, CTL_EOL); 1797} 1798 1799void 1800ip_statinc(u_int stat) 1801{ 1802 1803 KASSERT(stat < IP_NSTATS); 1804 IP_STATINC(stat); 1805} 1806