ip_input.c revision 1.367
1/* $NetBSD: ip_input.c,v 1.367 2018/02/05 13:34:20 maxv 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 1.367 2018/02/05 13:34:20 maxv 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 /* GATEWAY */ 157#define IPFORWARDING 0 /* don't forward IP packets not for us */ 158#endif /* GATEWAY */ 159#endif /* IPFORWARDING */ 160#ifndef IPSENDREDIRECTS 161#define IPSENDREDIRECTS 1 162#endif 163#ifndef IPFORWSRCRT 164#define IPFORWSRCRT 0 /* forward source-routed packets */ 165#endif 166#ifndef IPALLOWSRCRT 167#define IPALLOWSRCRT 0 /* allow source-routed packets */ 168#endif 169#ifndef IPMTUDISC 170#define IPMTUDISC 1 171#endif 172#ifndef IPMTUDISCTIMEOUT 173#define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */ 174#endif 175 176/* 177 * Note: DIRECTED_BROADCAST is handled this way so that previous 178 * configuration using this option will Just Work. 179 */ 180#ifndef IPDIRECTEDBCAST 181#ifdef DIRECTED_BROADCAST 182#define IPDIRECTEDBCAST 1 183#else 184#define IPDIRECTEDBCAST 0 185#endif /* DIRECTED_BROADCAST */ 186#endif /* IPDIRECTEDBCAST */ 187int ipforwarding = IPFORWARDING; 188int ipsendredirects = IPSENDREDIRECTS; 189int ip_defttl = IPDEFTTL; 190int ip_forwsrcrt = IPFORWSRCRT; 191int ip_directedbcast = IPDIRECTEDBCAST; 192int ip_allowsrcrt = IPALLOWSRCRT; 193int ip_mtudisc = IPMTUDISC; 194int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 195 196int ip_do_randomid = 0; 197 198/* 199 * XXX - Setting ip_checkinterface mostly implements the receive side of 200 * the Strong ES model described in RFC 1122, but since the routing table 201 * and transmit implementation do not implement the Strong ES model, 202 * setting this to 1 results in an odd hybrid. 203 * 204 * XXX - ip_checkinterface currently must be disabled if you use ipnat 205 * to translate the destination address to another local interface. 206 * 207 * XXX - ip_checkinterface must be disabled if you add IP aliases 208 * to the loopback interface instead of the interface where the 209 * packets for those addresses are received. 210 */ 211static int ip_checkinterface __read_mostly = 0; 212 213struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 214 215pktqueue_t * ip_pktq __read_mostly; 216pfil_head_t * inet_pfil_hook __read_mostly; 217ipid_state_t * ip_ids __read_mostly; 218percpu_t * ipstat_percpu __read_mostly; 219 220static percpu_t *ipforward_rt_percpu __cacheline_aligned; 221 222uint16_t ip_id; 223 224#ifdef INET_CSUM_COUNTERS 225#include <sys/device.h> 226 227struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 228 NULL, "inet", "hwcsum bad"); 229struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 230 NULL, "inet", "hwcsum ok"); 231struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 232 NULL, "inet", "swcsum"); 233 234#define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 235 236EVCNT_ATTACH_STATIC(ip_hwcsum_bad); 237EVCNT_ATTACH_STATIC(ip_hwcsum_ok); 238EVCNT_ATTACH_STATIC(ip_swcsum); 239 240#else 241 242#define INET_CSUM_COUNTER_INCR(ev) /* nothing */ 243 244#endif /* INET_CSUM_COUNTERS */ 245 246/* 247 * Used to save the IP options in case a protocol wants to respond 248 * to an incoming packet over the same route if the packet got here 249 * using IP source routing. This allows connection establishment and 250 * maintenance when the remote end is on a network that is not known 251 * to us. 252 */ 253struct ip_srcrt { 254 int isr_nhops; /* number of hops */ 255 struct in_addr isr_dst; /* final destination */ 256 char isr_nop; /* one NOP to align */ 257 char isr_hdr[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN & OFFSET */ 258 struct in_addr isr_routes[MAX_IPOPTLEN/sizeof(struct in_addr)]; 259}; 260 261static int ip_drainwanted; 262 263static void save_rte(struct mbuf *, u_char *, struct in_addr); 264 265#ifdef MBUFTRACE 266struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx"); 267struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx"); 268#endif 269 270static void ipintr(void *); 271static void ip_input(struct mbuf *); 272static void ip_forward(struct mbuf *, int, struct ifnet *); 273static bool ip_dooptions(struct mbuf *); 274static struct in_ifaddr *ip_rtaddr(struct in_addr, struct psref *); 275static void sysctl_net_inet_ip_setup(struct sysctllog **); 276 277static struct in_ifaddr *ip_match_our_address(struct ifnet *, struct ip *, 278 int *); 279static struct in_ifaddr *ip_match_our_address_broadcast(struct ifnet *, 280 struct ip *); 281 282#ifdef NET_MPSAFE 283#define SOFTNET_LOCK() mutex_enter(softnet_lock) 284#define SOFTNET_UNLOCK() mutex_exit(softnet_lock) 285#else 286#define SOFTNET_LOCK() KASSERT(mutex_owned(softnet_lock)) 287#define SOFTNET_UNLOCK() KASSERT(mutex_owned(softnet_lock)) 288#endif 289 290/* 291 * IP initialization: fill in IP protocol switch table. 292 * All protocols not implemented in kernel go to raw IP protocol handler. 293 */ 294void 295ip_init(void) 296{ 297 const struct protosw *pr; 298 299 in_init(); 300 sysctl_net_inet_ip_setup(NULL); 301 302 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 303 KASSERT(pr != NULL); 304 305 ip_pktq = pktq_create(IFQ_MAXLEN, ipintr, NULL); 306 KASSERT(ip_pktq != NULL); 307 308 for (u_int i = 0; i < IPPROTO_MAX; i++) { 309 ip_protox[i] = pr - inetsw; 310 } 311 for (pr = inetdomain.dom_protosw; 312 pr < inetdomain.dom_protoswNPROTOSW; pr++) 313 if (pr->pr_domain->dom_family == PF_INET && 314 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 315 ip_protox[pr->pr_protocol] = pr - inetsw; 316 317 ip_reass_init(); 318 319 ip_ids = ip_id_init(); 320 ip_id = time_uptime & 0xfffff; 321 322#ifdef GATEWAY 323 ipflow_init(); 324#endif 325 326 /* Register our Packet Filter hook. */ 327 inet_pfil_hook = pfil_head_create(PFIL_TYPE_AF, (void *)AF_INET); 328 KASSERT(inet_pfil_hook != NULL); 329 330#ifdef MBUFTRACE 331 MOWNER_ATTACH(&ip_tx_mowner); 332 MOWNER_ATTACH(&ip_rx_mowner); 333#endif /* MBUFTRACE */ 334 335 ipstat_percpu = percpu_alloc(sizeof(uint64_t) * IP_NSTATS); 336 ipforward_rt_percpu = percpu_alloc(sizeof(struct route)); 337 ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout); 338} 339 340static struct in_ifaddr * 341ip_match_our_address(struct ifnet *ifp, struct ip *ip, int *downmatch) 342{ 343 struct in_ifaddr *ia = NULL; 344 int checkif; 345 346 /* 347 * Enable a consistency check between the destination address 348 * and the arrival interface for a unicast packet (the RFC 1122 349 * strong ES model) if IP forwarding is disabled and the packet 350 * is not locally generated. 351 * 352 * XXX - Checking also should be disabled if the destination 353 * address is ipnat'ed to a different interface. 354 * 355 * XXX - Checking is incompatible with IP aliases added 356 * to the loopback interface instead of the interface where 357 * the packets are received. 358 * 359 * XXX - We need to add a per ifaddr flag for this so that 360 * we get finer grain control. 361 */ 362 checkif = ip_checkinterface && (ipforwarding == 0) && 363 (ifp->if_flags & IFF_LOOPBACK) == 0; 364 365 IN_ADDRHASH_READER_FOREACH(ia, ip->ip_dst.s_addr) { 366 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) { 367 if (ia->ia4_flags & IN_IFF_NOTREADY) 368 continue; 369 if (checkif && ia->ia_ifp != ifp) 370 continue; 371 if ((ia->ia_ifp->if_flags & IFF_UP) == 0) { 372 (*downmatch)++; 373 continue; 374 } 375 if (ia->ia4_flags & IN_IFF_DETACHED && 376 (ifp->if_flags & IFF_LOOPBACK) == 0) 377 continue; 378 break; 379 } 380 } 381 382 return ia; 383} 384 385static struct in_ifaddr * 386ip_match_our_address_broadcast(struct ifnet *ifp, struct ip *ip) 387{ 388 struct in_ifaddr *ia = NULL; 389 struct ifaddr *ifa; 390 391 IFADDR_READER_FOREACH(ifa, ifp) { 392 if (ifa->ifa_addr->sa_family != AF_INET) 393 continue; 394 ia = ifatoia(ifa); 395 if (ia->ia4_flags & IN_IFF_NOTREADY) 396 continue; 397 if (ia->ia4_flags & IN_IFF_DETACHED && 398 (ifp->if_flags & IFF_LOOPBACK) == 0) 399 continue; 400 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 401 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 402 /* 403 * Look for all-0's host part (old broadcast addr), 404 * either for subnet or net. 405 */ 406 ip->ip_dst.s_addr == ia->ia_subnet || 407 ip->ip_dst.s_addr == ia->ia_net) 408 goto matched; 409 /* 410 * An interface with IP address zero accepts 411 * all packets that arrive on that interface. 412 */ 413 if (in_nullhost(ia->ia_addr.sin_addr)) 414 goto matched; 415 } 416 ia = NULL; 417 418matched: 419 return ia; 420} 421 422/* 423 * IP software interrupt routine. 424 */ 425static void 426ipintr(void *arg __unused) 427{ 428 struct mbuf *m; 429 430 KASSERT(cpu_softintr_p()); 431 432 SOFTNET_LOCK_UNLESS_NET_MPSAFE(); 433 while ((m = pktq_dequeue(ip_pktq)) != NULL) { 434 ip_input(m); 435 } 436 SOFTNET_UNLOCK_UNLESS_NET_MPSAFE(); 437} 438 439/* 440 * IP input routine. Checksum and byte swap header. If fragmented 441 * try to reassemble. Process options. Pass to next level. 442 */ 443static void 444ip_input(struct mbuf *m) 445{ 446 struct ip *ip = NULL; 447 struct in_ifaddr *ia = NULL; 448 int hlen = 0, len; 449 int downmatch; 450 int srcrt = 0; 451 ifnet_t *ifp; 452 struct psref psref; 453 int s; 454 455 KASSERTMSG(cpu_softintr_p(), "ip_input: not in the software " 456 "interrupt handler; synchronization assumptions violated"); 457 458 MCLAIM(m, &ip_rx_mowner); 459 KASSERT((m->m_flags & M_PKTHDR) != 0); 460 461 ifp = m_get_rcvif_psref(m, &psref); 462 if (__predict_false(ifp == NULL)) 463 goto out; 464 465 /* 466 * If no IP addresses have been set yet but the interfaces 467 * are receiving, can't do anything with incoming packets yet. 468 * Note: we pre-check without locks held. 469 */ 470 if (IN_ADDRLIST_READER_EMPTY()) 471 goto out; 472 IP_STATINC(IP_STAT_TOTAL); 473 474 /* 475 * If the IP header is not aligned, slurp it up into a new 476 * mbuf with space for link headers, in the event we forward 477 * it. Otherwise, if it is aligned, make sure the entire 478 * base IP header is in the first mbuf of the chain. 479 */ 480 if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) { 481 if ((m = m_copyup(m, sizeof(struct ip), 482 (max_linkhdr + 3) & ~3)) == NULL) { 483 /* XXXJRT new stat, please */ 484 IP_STATINC(IP_STAT_TOOSMALL); 485 goto out; 486 } 487 } else if (__predict_false(m->m_len < sizeof(struct ip))) { 488 if ((m = m_pullup(m, sizeof(struct ip))) == NULL) { 489 IP_STATINC(IP_STAT_TOOSMALL); 490 goto out; 491 } 492 } 493 ip = mtod(m, struct ip *); 494 if (ip->ip_v != IPVERSION) { 495 IP_STATINC(IP_STAT_BADVERS); 496 goto out; 497 } 498 hlen = ip->ip_hl << 2; 499 if (hlen < sizeof(struct ip)) { /* minimum header length */ 500 IP_STATINC(IP_STAT_BADHLEN); 501 goto out; 502 } 503 if (hlen > m->m_len) { 504 if ((m = m_pullup(m, hlen)) == NULL) { 505 IP_STATINC(IP_STAT_BADHLEN); 506 goto out; 507 } 508 ip = mtod(m, struct ip *); 509 } 510 511 /* 512 * RFC1122: packets with a multicast source address are 513 * not allowed. 514 */ 515 if (IN_MULTICAST(ip->ip_src.s_addr)) { 516 IP_STATINC(IP_STAT_BADADDR); 517 goto out; 518 } 519 520 /* 127/8 must not appear on wire - RFC1122 */ 521 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 522 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 523 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 524 IP_STATINC(IP_STAT_BADADDR); 525 goto out; 526 } 527 } 528 529 switch (m->m_pkthdr.csum_flags & 530 ((ifp->if_csum_flags_rx & M_CSUM_IPv4) | M_CSUM_IPv4_BAD)) { 531 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 532 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad); 533 IP_STATINC(IP_STAT_BADSUM); 534 goto out; 535 536 case M_CSUM_IPv4: 537 /* Checksum was okay. */ 538 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok); 539 break; 540 541 default: 542 /* 543 * Must compute it ourselves. Maybe skip checksum on 544 * loopback interfaces. 545 */ 546 if (__predict_true(!(ifp->if_flags & IFF_LOOPBACK) || 547 ip_do_loopback_cksum)) { 548 INET_CSUM_COUNTER_INCR(&ip_swcsum); 549 if (in_cksum(m, hlen) != 0) { 550 IP_STATINC(IP_STAT_BADSUM); 551 goto out; 552 } 553 } 554 break; 555 } 556 557 /* Retrieve the packet length. */ 558 len = ntohs(ip->ip_len); 559 560 /* 561 * Check for additional length bogosity 562 */ 563 if (len < hlen) { 564 IP_STATINC(IP_STAT_BADLEN); 565 goto out; 566 } 567 568 /* 569 * Check that the amount of data in the buffers is at least as much 570 * as the IP header would have us expect. Trim mbufs if longer than 571 * we expect. Drop packet if shorter than we expect. 572 */ 573 if (m->m_pkthdr.len < len) { 574 IP_STATINC(IP_STAT_TOOSHORT); 575 goto out; 576 } 577 if (m->m_pkthdr.len > len) { 578 if (m->m_len == m->m_pkthdr.len) { 579 m->m_len = len; 580 m->m_pkthdr.len = len; 581 } else 582 m_adj(m, len - m->m_pkthdr.len); 583 } 584 585 /* 586 * Assume that we can create a fast-forward IP flow entry 587 * based on this packet. 588 */ 589 m->m_flags |= M_CANFASTFWD; 590 591 /* 592 * Run through list of hooks for input packets. If there are any 593 * filters which require that additional packets in the flow are 594 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 595 * Note that filters must _never_ set this flag, as another filter 596 * in the list may have previously cleared it. 597 */ 598#if defined(IPSEC) 599 if (!ipsec_used || !ipsec_indone(m)) 600#else 601 if (1) 602#endif 603 { 604 struct in_addr odst = ip->ip_dst; 605 bool freed; 606 607 freed = pfil_run_hooks(inet_pfil_hook, &m, ifp, PFIL_IN) != 0; 608 if (freed || m == NULL) { 609 m = NULL; 610 goto out; 611 } 612 ip = mtod(m, struct ip *); 613 hlen = ip->ip_hl << 2; 614 615 /* 616 * XXX The setting of "srcrt" here is to prevent ip_forward() 617 * from generating ICMP redirects for packets that have 618 * been redirected by a hook back out on to the same LAN that 619 * they came from and is not an indication that the packet 620 * is being inffluenced by source routing options. This 621 * allows things like 622 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp" 623 * where tlp0 is both on the 1.1.1.0/24 network and is the 624 * default route for hosts on 1.1.1.0/24. Of course this 625 * also requires a "map tlp0 ..." to complete the story. 626 * One might argue whether or not this kind of network config. 627 * should be supported in this manner... 628 */ 629 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 630 } 631 632#ifdef ALTQ 633 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 634 if (altq_input) { 635 SOFTNET_LOCK(); 636 if ((*altq_input)(m, AF_INET) == 0) { 637 /* Packet dropped by traffic conditioner. */ 638 SOFTNET_UNLOCK(); 639 m = NULL; 640 goto out; 641 } 642 SOFTNET_UNLOCK(); 643 } 644#endif 645 646 /* 647 * Process options and, if not destined for us, 648 * ship it on. ip_dooptions returns 1 when an 649 * error was detected (causing an icmp message 650 * to be sent and the original packet to be freed). 651 */ 652 if (hlen > sizeof(struct ip) && ip_dooptions(m)) { 653 m = NULL; 654 goto out; 655 } 656 657 /* 658 * Check our list of addresses, to see if the packet is for us. 659 * 660 * Traditional 4.4BSD did not consult IFF_UP at all. 661 * The behavior here is to treat addresses on !IFF_UP interface 662 * or IN_IFF_NOTREADY addresses as not mine. 663 */ 664 downmatch = 0; 665 s = pserialize_read_enter(); 666 ia = ip_match_our_address(ifp, ip, &downmatch); 667 if (ia != NULL) { 668 pserialize_read_exit(s); 669 goto ours; 670 } 671 672 if (ifp->if_flags & IFF_BROADCAST) { 673 ia = ip_match_our_address_broadcast(ifp, ip); 674 if (ia != NULL) { 675 pserialize_read_exit(s); 676 goto ours; 677 } 678 } 679 pserialize_read_exit(s); 680 681 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 682#ifdef MROUTING 683 extern struct socket *ip_mrouter; 684 685 if (ip_mrouter) { 686 /* 687 * If we are acting as a multicast router, all 688 * incoming multicast packets are passed to the 689 * kernel-level multicast forwarding function. 690 * The packet is returned (relatively) intact; if 691 * ip_mforward() returns a non-zero value, the packet 692 * must be discarded, else it may be accepted below. 693 * 694 * (The IP ident field is put in the same byte order 695 * as expected when ip_mforward() is called from 696 * ip_output().) 697 */ 698 SOFTNET_LOCK(); 699 if (ip_mforward(m, ifp) != 0) { 700 SOFTNET_UNLOCK(); 701 IP_STATINC(IP_STAT_CANTFORWARD); 702 goto out; 703 } 704 SOFTNET_UNLOCK(); 705 706 /* 707 * The process-level routing demon needs to receive 708 * all multicast IGMP packets, whether or not this 709 * host belongs to their destination groups. 710 */ 711 if (ip->ip_p == IPPROTO_IGMP) { 712 goto ours; 713 } 714 IP_STATINC(IP_STAT_CANTFORWARD); 715 } 716#endif 717 /* 718 * See if we belong to the destination multicast group on the 719 * arrival interface. 720 */ 721 if (!in_multi_group(ip->ip_dst, ifp, 0)) { 722 IP_STATINC(IP_STAT_CANTFORWARD); 723 goto out; 724 } 725 goto ours; 726 } 727 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 728 in_nullhost(ip->ip_dst)) 729 goto ours; 730 731 /* 732 * Not for us; forward if possible and desirable. 733 */ 734 if (ipforwarding == 0) { 735 m_put_rcvif_psref(ifp, &psref); 736 IP_STATINC(IP_STAT_CANTFORWARD); 737 m_freem(m); 738 } else { 739 /* 740 * If ip_dst matched any of my address on !IFF_UP interface, 741 * and there's no IFF_UP interface that matches ip_dst, 742 * send icmp unreach. Forwarding it will result in in-kernel 743 * forwarding loop till TTL goes to 0. 744 */ 745 if (downmatch) { 746 m_put_rcvif_psref(ifp, &psref); 747 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 748 IP_STATINC(IP_STAT_CANTFORWARD); 749 return; 750 } 751#ifdef IPSEC 752 /* Check the security policy (SP) for the packet */ 753 if (ipsec_used) { 754 if (ipsec4_input(m, IP_FORWARDING | 755 (ip_directedbcast ? IP_ALLOWBROADCAST : 0)) != 0) { 756 goto out; 757 } 758 } 759#endif 760 ip_forward(m, srcrt, ifp); 761 m_put_rcvif_psref(ifp, &psref); 762 } 763 return; 764 765ours: 766 m_put_rcvif_psref(ifp, &psref); 767 ifp = NULL; 768 769 /* 770 * If offset or IP_MF are set, must reassemble. 771 */ 772 if (ip->ip_off & ~htons(IP_DF|IP_RF)) { 773 /* 774 * Pass to IP reassembly mechanism. 775 */ 776 if (ip_reass_packet(&m, ip) != 0) { 777 /* Failed; invalid fragment(s) or packet. */ 778 goto out; 779 } 780 if (m == NULL) { 781 /* More fragments should come; silently return. */ 782 goto out; 783 } 784 /* 785 * Reassembly is done, we have the final packet. 786 * Update cached data in local variable(s). 787 */ 788 ip = mtod(m, struct ip *); 789 hlen = ip->ip_hl << 2; 790 } 791 792#ifdef IPSEC 793 /* 794 * Enforce IPsec policy checking if we are seeing last header. 795 * Note that we do not visit this with protocols with PCB layer 796 * code - like UDP/TCP/raw IP. 797 */ 798 if (ipsec_used && 799 (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 800 if (ipsec4_input(m, 0) != 0) { 801 goto out; 802 } 803 } 804#endif 805 806 /* 807 * Switch out to protocol's input routine. 808 */ 809#if IFA_STATS 810 if (ia && ip) { 811 struct in_ifaddr *_ia; 812 /* 813 * Keep a reference from ip_match_our_address with psref 814 * is expensive, so explore ia here again. 815 */ 816 s = pserialize_read_enter(); 817 _ia = in_get_ia(ip->ip_dst); 818 _ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len); 819 pserialize_read_exit(s); 820 } 821#endif 822 IP_STATINC(IP_STAT_DELIVERED); 823 824 const int off = hlen, nh = ip->ip_p; 825 826 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 827 return; 828 829out: 830 m_put_rcvif_psref(ifp, &psref); 831 if (m != NULL) 832 m_freem(m); 833} 834 835/* 836 * IP timer processing. 837 */ 838void 839ip_slowtimo(void) 840{ 841 842 SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE(); 843 844 ip_reass_slowtimo(); 845 846 SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE(); 847} 848 849/* 850 * IP drain processing. 851 */ 852void 853ip_drain(void) 854{ 855 856 KERNEL_LOCK(1, NULL); 857 ip_reass_drain(); 858 KERNEL_UNLOCK_ONE(NULL); 859} 860 861/* 862 * ip_dooptions: perform option processing on a datagram, possibly discarding 863 * it if bad options are encountered, or forwarding it if source-routed. 864 * 865 * => Returns true if packet has been forwarded/freed. 866 * => Returns false if the packet should be processed further. 867 */ 868static bool 869ip_dooptions(struct mbuf *m) 870{ 871 struct ip *ip = mtod(m, struct ip *); 872 u_char *cp, *cp0; 873 struct ip_timestamp *ipt; 874 struct in_ifaddr *ia; 875 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 876 struct in_addr dst; 877 n_time ntime; 878 struct ifaddr *ifa = NULL; 879 int s; 880 881 dst = ip->ip_dst; 882 cp = (u_char *)(ip + 1); 883 cnt = (ip->ip_hl << 2) - sizeof(struct ip); 884 for (; cnt > 0; cnt -= optlen, cp += optlen) { 885 opt = cp[IPOPT_OPTVAL]; 886 if (opt == IPOPT_EOL) 887 break; 888 if (opt == IPOPT_NOP) 889 optlen = 1; 890 else { 891 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 892 code = &cp[IPOPT_OLEN] - (u_char *)ip; 893 goto bad; 894 } 895 optlen = cp[IPOPT_OLEN]; 896 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 897 code = &cp[IPOPT_OLEN] - (u_char *)ip; 898 goto bad; 899 } 900 } 901 switch (opt) { 902 903 default: 904 break; 905 906 /* 907 * Source routing with record. 908 * Find interface with current destination address. 909 * If none on this machine then drop if strictly routed, 910 * or do nothing if loosely routed. 911 * Record interface address and bring up next address 912 * component. If strictly routed make sure next 913 * address is on directly accessible net. 914 */ 915 case IPOPT_LSRR: 916 case IPOPT_SSRR: { 917 struct psref psref; 918 struct sockaddr_in ipaddr = { 919 .sin_len = sizeof(ipaddr), 920 .sin_family = AF_INET, 921 }; 922 923 if (ip_allowsrcrt == 0) { 924 type = ICMP_UNREACH; 925 code = ICMP_UNREACH_NET_PROHIB; 926 goto bad; 927 } 928 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 929 code = &cp[IPOPT_OLEN] - (u_char *)ip; 930 goto bad; 931 } 932 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 933 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 934 goto bad; 935 } 936 ipaddr.sin_addr = ip->ip_dst; 937 938 s = pserialize_read_enter(); 939 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 940 if (ifa == NULL) { 941 pserialize_read_exit(s); 942 if (opt == IPOPT_SSRR) { 943 type = ICMP_UNREACH; 944 code = ICMP_UNREACH_SRCFAIL; 945 goto bad; 946 } 947 /* 948 * Loose routing, and not at next destination 949 * yet; nothing to do except forward. 950 */ 951 break; 952 } 953 pserialize_read_exit(s); 954 955 off--; /* 0 origin */ 956 if ((off + sizeof(struct in_addr)) > optlen) { 957 /* 958 * End of source route. Should be for us. 959 */ 960 save_rte(m, cp, ip->ip_src); 961 break; 962 } 963 /* 964 * locate outgoing interface 965 */ 966 memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off), 967 sizeof(ipaddr.sin_addr)); 968 if (opt == IPOPT_SSRR) { 969 ifa = ifa_ifwithladdr_psref(sintosa(&ipaddr), 970 &psref); 971 if (ifa != NULL) 972 ia = ifatoia(ifa); 973 else 974 ia = NULL; 975 } else { 976 ia = ip_rtaddr(ipaddr.sin_addr, &psref); 977 } 978 if (ia == NULL) { 979 type = ICMP_UNREACH; 980 code = ICMP_UNREACH_SRCFAIL; 981 goto bad; 982 } 983 ip->ip_dst = ipaddr.sin_addr; 984 bcopy((void *)&ia->ia_addr.sin_addr, 985 (void *)(cp + off), sizeof(struct in_addr)); 986 ia4_release(ia, &psref); 987 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 988 /* 989 * Let ip_intr's mcast routing check handle mcast pkts 990 */ 991 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 992 break; 993 } 994 995 case IPOPT_RR: { 996 struct psref psref; 997 struct sockaddr_in ipaddr = { 998 .sin_len = sizeof(ipaddr), 999 .sin_family = AF_INET, 1000 }; 1001 1002 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1003 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1004 goto bad; 1005 } 1006 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1007 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1008 goto bad; 1009 } 1010 /* 1011 * If no space remains, ignore. 1012 */ 1013 off--; /* 0 origin */ 1014 if ((off + sizeof(struct in_addr)) > optlen) 1015 break; 1016 memcpy((void *)&ipaddr.sin_addr, (void *)(&ip->ip_dst), 1017 sizeof(ipaddr.sin_addr)); 1018 /* 1019 * locate outgoing interface; if we're the destination, 1020 * use the incoming interface (should be same). 1021 */ 1022 ifa = ifa_ifwithaddr_psref(sintosa(&ipaddr), &psref); 1023 if (ifa == NULL) { 1024 ia = ip_rtaddr(ipaddr.sin_addr, &psref); 1025 if (ia == NULL) { 1026 type = ICMP_UNREACH; 1027 code = ICMP_UNREACH_HOST; 1028 goto bad; 1029 } 1030 } else { 1031 ia = ifatoia(ifa); 1032 } 1033 bcopy((void *)&ia->ia_addr.sin_addr, 1034 (void *)(cp + off), sizeof(struct in_addr)); 1035 ia4_release(ia, &psref); 1036 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1037 break; 1038 } 1039 1040 case IPOPT_TS: 1041 code = cp - (u_char *)ip; 1042 ipt = (struct ip_timestamp *)cp; 1043 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1044 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1045 goto bad; 1046 } 1047 if (ipt->ipt_ptr < 5) { 1048 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1049 goto bad; 1050 } 1051 if (ipt->ipt_ptr > ipt->ipt_len - sizeof(int32_t)) { 1052 if (++ipt->ipt_oflw == 0) { 1053 code = (u_char *)&ipt->ipt_ptr - 1054 (u_char *)ip; 1055 goto bad; 1056 } 1057 break; 1058 } 1059 cp0 = (cp + ipt->ipt_ptr - 1); 1060 switch (ipt->ipt_flg) { 1061 1062 case IPOPT_TS_TSONLY: 1063 break; 1064 1065 case IPOPT_TS_TSANDADDR: { 1066 struct ifnet *rcvif; 1067 int _s, _ss; 1068 struct sockaddr_in ipaddr = { 1069 .sin_len = sizeof(ipaddr), 1070 .sin_family = AF_INET, 1071 }; 1072 1073 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1074 sizeof(struct in_addr) > ipt->ipt_len) { 1075 code = (u_char *)&ipt->ipt_ptr - 1076 (u_char *)ip; 1077 goto bad; 1078 } 1079 ipaddr.sin_addr = dst; 1080 _ss = pserialize_read_enter(); 1081 rcvif = m_get_rcvif(m, &_s); 1082 if (__predict_true(rcvif != NULL)) { 1083 ifa = ifaof_ifpforaddr(sintosa(&ipaddr), 1084 rcvif); 1085 } 1086 m_put_rcvif(rcvif, &_s); 1087 if (ifa == NULL) { 1088 pserialize_read_exit(_ss); 1089 break; 1090 } 1091 ia = ifatoia(ifa); 1092 bcopy(&ia->ia_addr.sin_addr, 1093 cp0, sizeof(struct in_addr)); 1094 pserialize_read_exit(_ss); 1095 ipt->ipt_ptr += sizeof(struct in_addr); 1096 break; 1097 } 1098 1099 case IPOPT_TS_PRESPEC: { 1100 struct sockaddr_in ipaddr = { 1101 .sin_len = sizeof(ipaddr), 1102 .sin_family = AF_INET, 1103 }; 1104 1105 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1106 sizeof(struct in_addr) > ipt->ipt_len) { 1107 code = (u_char *)&ipt->ipt_ptr - 1108 (u_char *)ip; 1109 goto bad; 1110 } 1111 memcpy(&ipaddr.sin_addr, cp0, 1112 sizeof(struct in_addr)); 1113 s = pserialize_read_enter(); 1114 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 1115 if (ifa == NULL) { 1116 pserialize_read_exit(s); 1117 continue; 1118 } 1119 pserialize_read_exit(s); 1120 ipt->ipt_ptr += sizeof(struct in_addr); 1121 break; 1122 } 1123 1124 default: 1125 /* XXX can't take &ipt->ipt_flg */ 1126 code = (u_char *)&ipt->ipt_ptr - 1127 (u_char *)ip + 1; 1128 goto bad; 1129 } 1130 ntime = iptime(); 1131 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1132 memmove((char *)cp + ipt->ipt_ptr - 1, cp0, 1133 sizeof(n_time)); 1134 ipt->ipt_ptr += sizeof(n_time); 1135 } 1136 } 1137 if (forward) { 1138 struct ifnet *rcvif; 1139 struct psref _psref; 1140 1141 if (ip_forwsrcrt == 0) { 1142 type = ICMP_UNREACH; 1143 code = ICMP_UNREACH_SRCFAIL; 1144 goto bad; 1145 } 1146 1147 rcvif = m_get_rcvif_psref(m, &_psref); 1148 if (__predict_false(rcvif == NULL)) { 1149 type = ICMP_UNREACH; 1150 code = ICMP_UNREACH_HOST; 1151 goto bad; 1152 } 1153 ip_forward(m, 1, rcvif); 1154 m_put_rcvif_psref(rcvif, &_psref); 1155 return true; 1156 } 1157 return false; 1158bad: 1159 icmp_error(m, type, code, 0, 0); 1160 IP_STATINC(IP_STAT_BADOPTIONS); 1161 return true; 1162} 1163 1164/* 1165 * ip_rtaddr: given address of next destination (final or next hop), 1166 * return internet address info of interface to be used to get there. 1167 */ 1168static struct in_ifaddr * 1169ip_rtaddr(struct in_addr dst, struct psref *psref) 1170{ 1171 struct rtentry *rt; 1172 union { 1173 struct sockaddr dst; 1174 struct sockaddr_in dst4; 1175 } u; 1176 struct route *ro; 1177 1178 sockaddr_in_init(&u.dst4, &dst, 0); 1179 1180 ro = percpu_getref(ipforward_rt_percpu); 1181 rt = rtcache_lookup(ro, &u.dst); 1182 if (rt == NULL) { 1183 percpu_putref(ipforward_rt_percpu); 1184 return NULL; 1185 } 1186 1187 ia4_acquire(ifatoia(rt->rt_ifa), psref); 1188 rtcache_unref(rt, ro); 1189 percpu_putref(ipforward_rt_percpu); 1190 1191 return ifatoia(rt->rt_ifa); 1192} 1193 1194/* 1195 * save_rte: save incoming source route for use in replies, to be picked 1196 * up later by ip_srcroute if the receiver is interested. 1197 */ 1198static void 1199save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1200{ 1201 struct ip_srcrt *isr; 1202 struct m_tag *mtag; 1203 unsigned olen; 1204 1205 olen = option[IPOPT_OLEN]; 1206 if (olen > sizeof(isr->isr_hdr) + sizeof(isr->isr_routes)) 1207 return; 1208 1209 mtag = m_tag_get(PACKET_TAG_SRCROUTE, sizeof(*isr), M_NOWAIT); 1210 if (mtag == NULL) 1211 return; 1212 isr = (struct ip_srcrt *)(mtag + 1); 1213 1214 memcpy(isr->isr_hdr, option, olen); 1215 isr->isr_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1216 isr->isr_dst = dst; 1217 m_tag_prepend(m, mtag); 1218} 1219 1220/* 1221 * Retrieve incoming source route for use in replies, 1222 * in the same form used by setsockopt. 1223 * The first hop is placed before the options, will be removed later. 1224 */ 1225struct mbuf * 1226ip_srcroute(struct mbuf *m0) 1227{ 1228 struct in_addr *p, *q; 1229 struct mbuf *m; 1230 struct ip_srcrt *isr; 1231 struct m_tag *mtag; 1232 1233 mtag = m_tag_find(m0, PACKET_TAG_SRCROUTE, NULL); 1234 if (mtag == NULL) 1235 return NULL; 1236 isr = (struct ip_srcrt *)(mtag + 1); 1237 1238 if (isr->isr_nhops == 0) 1239 return NULL; 1240 1241 m = m_get(M_DONTWAIT, MT_SOOPTS); 1242 if (m == NULL) 1243 return NULL; 1244 1245 MCLAIM(m, &inetdomain.dom_mowner); 1246#define OPTSIZ (sizeof(isr->isr_nop) + sizeof(isr->isr_hdr)) 1247 1248 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + header) */ 1249 m->m_len = (isr->isr_nhops + 1) * sizeof(struct in_addr) + OPTSIZ; 1250 1251 /* 1252 * First save first hop for return route 1253 */ 1254 p = &(isr->isr_routes[isr->isr_nhops - 1]); 1255 *(mtod(m, struct in_addr *)) = *p--; 1256 1257 /* 1258 * Copy option fields and padding (nop) to mbuf. 1259 */ 1260 isr->isr_nop = IPOPT_NOP; 1261 isr->isr_hdr[IPOPT_OFFSET] = IPOPT_MINOFF; 1262 memmove(mtod(m, char *) + sizeof(struct in_addr), &isr->isr_nop, 1263 OPTSIZ); 1264 q = (struct in_addr *)(mtod(m, char *) + 1265 sizeof(struct in_addr) + OPTSIZ); 1266#undef OPTSIZ 1267 /* 1268 * Record return path as an IP source route, 1269 * reversing the path (pointers are now aligned). 1270 */ 1271 while (p >= isr->isr_routes) { 1272 *q++ = *p--; 1273 } 1274 /* 1275 * Last hop goes to final destination. 1276 */ 1277 *q = isr->isr_dst; 1278 m_tag_delete(m0, mtag); 1279 return m; 1280} 1281 1282const int inetctlerrmap[PRC_NCMDS] = { 1283 [PRC_MSGSIZE] = EMSGSIZE, 1284 [PRC_HOSTDEAD] = EHOSTDOWN, 1285 [PRC_HOSTUNREACH] = EHOSTUNREACH, 1286 [PRC_UNREACH_NET] = EHOSTUNREACH, 1287 [PRC_UNREACH_HOST] = EHOSTUNREACH, 1288 [PRC_UNREACH_PROTOCOL] = ECONNREFUSED, 1289 [PRC_UNREACH_PORT] = ECONNREFUSED, 1290 [PRC_UNREACH_SRCFAIL] = EHOSTUNREACH, 1291 [PRC_PARAMPROB] = ENOPROTOOPT, 1292}; 1293 1294void 1295ip_fasttimo(void) 1296{ 1297 if (ip_drainwanted) { 1298 ip_drain(); 1299 ip_drainwanted = 0; 1300 } 1301} 1302 1303void 1304ip_drainstub(void) 1305{ 1306 ip_drainwanted = 1; 1307} 1308 1309/* 1310 * Forward a packet. If some error occurs return the sender 1311 * an icmp packet. Note we can't always generate a meaningful 1312 * icmp message because icmp doesn't have a large enough repertoire 1313 * of codes and types. 1314 * 1315 * If not forwarding, just drop the packet. This could be confusing 1316 * if ipforwarding was zero but some routing protocol was advancing 1317 * us as a gateway to somewhere. However, we must let the routing 1318 * protocol deal with that. 1319 * 1320 * The srcrt parameter indicates whether the packet is being forwarded 1321 * via a source route. 1322 */ 1323static void 1324ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif) 1325{ 1326 struct ip *ip = mtod(m, struct ip *); 1327 struct rtentry *rt; 1328 int error, type = 0, code = 0, destmtu = 0; 1329 struct mbuf *mcopy; 1330 n_long dest; 1331 union { 1332 struct sockaddr dst; 1333 struct sockaddr_in dst4; 1334 } u; 1335 uint64_t *ips; 1336 struct route *ro; 1337 1338 KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software " 1339 "interrupt handler; synchronization assumptions violated"); 1340 1341 /* 1342 * We are now in the output path. 1343 */ 1344 MCLAIM(m, &ip_tx_mowner); 1345 1346 /* 1347 * Clear any in-bound checksum flags for this packet. 1348 */ 1349 m->m_pkthdr.csum_flags = 0; 1350 1351 dest = 0; 1352 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1353 IP_STATINC(IP_STAT_CANTFORWARD); 1354 m_freem(m); 1355 return; 1356 } 1357 1358 if (ip->ip_ttl <= IPTTLDEC) { 1359 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1360 return; 1361 } 1362 1363 sockaddr_in_init(&u.dst4, &ip->ip_dst, 0); 1364 1365 ro = percpu_getref(ipforward_rt_percpu); 1366 rt = rtcache_lookup(ro, &u.dst); 1367 if (rt == NULL) { 1368 percpu_putref(ipforward_rt_percpu); 1369 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0); 1370 return; 1371 } 1372 1373 /* 1374 * Save at most 68 bytes of the packet in case 1375 * we need to generate an ICMP message to the src. 1376 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1377 */ 1378 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1379 if (mcopy) 1380 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1381 1382 ip->ip_ttl -= IPTTLDEC; 1383 1384 /* 1385 * If forwarding packet using same interface that it came in on, 1386 * perhaps should send a redirect to sender to shortcut a hop. 1387 * Only send redirect if source is sending directly to us, 1388 * and if packet was not source routed (or has any options). 1389 * Also, don't send redirect if forwarding using a default route 1390 * or a route modified by a redirect. 1391 */ 1392 if (rt->rt_ifp == rcvif && 1393 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1394 !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) && 1395 ipsendredirects && !srcrt) { 1396 if (rt->rt_ifa && 1397 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1398 ifatoia(rt->rt_ifa)->ia_subnet) { 1399 if (rt->rt_flags & RTF_GATEWAY) 1400 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1401 else 1402 dest = ip->ip_dst.s_addr; 1403 /* 1404 * Router requirements says to only send host 1405 * redirects. 1406 */ 1407 type = ICMP_REDIRECT; 1408 code = ICMP_REDIRECT_HOST; 1409 } 1410 } 1411 rtcache_unref(rt, ro); 1412 1413 error = ip_output(m, NULL, ro, 1414 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1415 NULL, NULL); 1416 1417 if (error) { 1418 IP_STATINC(IP_STAT_CANTFORWARD); 1419 goto error; 1420 } 1421 1422 ips = IP_STAT_GETREF(); 1423 ips[IP_STAT_FORWARD]++; 1424 1425 if (type) { 1426 ips[IP_STAT_REDIRECTSENT]++; 1427 IP_STAT_PUTREF(); 1428 goto redirect; 1429 } 1430 1431 IP_STAT_PUTREF(); 1432 if (mcopy) { 1433#ifdef GATEWAY 1434 if (mcopy->m_flags & M_CANFASTFWD) 1435 ipflow_create(ro, mcopy); 1436#endif 1437 m_freem(mcopy); 1438 } 1439 1440 percpu_putref(ipforward_rt_percpu); 1441 return; 1442 1443redirect: 1444error: 1445 if (mcopy == NULL) { 1446 percpu_putref(ipforward_rt_percpu); 1447 return; 1448 } 1449 1450 switch (error) { 1451 1452 case 0: /* forwarded, but need redirect */ 1453 /* type, code set above */ 1454 break; 1455 1456 case ENETUNREACH: /* shouldn't happen, checked above */ 1457 case EHOSTUNREACH: 1458 case ENETDOWN: 1459 case EHOSTDOWN: 1460 default: 1461 type = ICMP_UNREACH; 1462 code = ICMP_UNREACH_HOST; 1463 break; 1464 1465 case EMSGSIZE: 1466 type = ICMP_UNREACH; 1467 code = ICMP_UNREACH_NEEDFRAG; 1468 1469 if ((rt = rtcache_validate(ro)) != NULL) { 1470 destmtu = rt->rt_ifp->if_mtu; 1471 rtcache_unref(rt, ro); 1472 } 1473#ifdef IPSEC 1474 if (ipsec_used) 1475 (void)ipsec4_forward(mcopy, &destmtu); 1476#endif 1477 IP_STATINC(IP_STAT_CANTFRAG); 1478 break; 1479 1480 case ENOBUFS: 1481 /* 1482 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812, 1483 * Requirements for IP Version 4 Routers. Source quench can 1484 * big problem under DoS attacks or if the underlying 1485 * interface is rate-limited. 1486 */ 1487 if (mcopy) 1488 m_freem(mcopy); 1489 percpu_putref(ipforward_rt_percpu); 1490 return; 1491 } 1492 icmp_error(mcopy, type, code, dest, destmtu); 1493 percpu_putref(ipforward_rt_percpu); 1494} 1495 1496void 1497ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1498 struct mbuf *m) 1499{ 1500 struct socket *so = inp->inp_socket; 1501 int inpflags = inp->inp_flags; 1502 1503 if (SOOPT_TIMESTAMP(so->so_options)) 1504 mp = sbsavetimestamp(so->so_options, m, mp); 1505 1506 if (inpflags & INP_RECVDSTADDR) { 1507 *mp = sbcreatecontrol(&ip->ip_dst, 1508 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1509 if (*mp) 1510 mp = &(*mp)->m_next; 1511 } 1512 1513 if (inpflags & INP_RECVTTL) { 1514 *mp = sbcreatecontrol(&ip->ip_ttl, 1515 sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP); 1516 if (*mp) 1517 mp = &(*mp)->m_next; 1518 } 1519 1520 struct psref psref; 1521 ifnet_t *ifp = m_get_rcvif_psref(m, &psref); 1522 if (__predict_false(ifp == NULL)) { 1523#ifdef DIAGNOSTIC 1524 printf("%s: missing receive interface\n", __func__); 1525#endif 1526 return; /* XXX should report error? */ 1527 } 1528 1529 if (inpflags & INP_RECVPKTINFO) { 1530 struct in_pktinfo ipi; 1531 ipi.ipi_addr = ip->ip_dst; 1532 ipi.ipi_ifindex = ifp->if_index; 1533 *mp = sbcreatecontrol(&ipi, 1534 sizeof(ipi), IP_PKTINFO, IPPROTO_IP); 1535 if (*mp) 1536 mp = &(*mp)->m_next; 1537 } 1538 if (inpflags & INP_RECVIF) { 1539 struct sockaddr_dl sdl; 1540 1541 sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0, 1542 NULL, 0); 1543 *mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP); 1544 if (*mp) 1545 mp = &(*mp)->m_next; 1546 } 1547 m_put_rcvif_psref(ifp, &psref); 1548} 1549 1550/* 1551 * sysctl helper routine for net.inet.ip.forwsrcrt. 1552 */ 1553static int 1554sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS) 1555{ 1556 int error, tmp; 1557 struct sysctlnode node; 1558 1559 node = *rnode; 1560 tmp = ip_forwsrcrt; 1561 node.sysctl_data = &tmp; 1562 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1563 if (error || newp == NULL) 1564 return (error); 1565 1566 error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT, 1567 0, NULL, NULL, NULL); 1568 if (error) 1569 return (error); 1570 1571 ip_forwsrcrt = tmp; 1572 1573 return (0); 1574} 1575 1576/* 1577 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the 1578 * range of the new value and tweaks timers if it changes. 1579 */ 1580static int 1581sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS) 1582{ 1583 int error, tmp; 1584 struct sysctlnode node; 1585 1586 icmp_mtudisc_lock(); 1587 1588 node = *rnode; 1589 tmp = ip_mtudisc_timeout; 1590 node.sysctl_data = &tmp; 1591 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1592 if (error || newp == NULL) 1593 goto out; 1594 if (tmp < 0) { 1595 error = EINVAL; 1596 goto out; 1597 } 1598 1599 ip_mtudisc_timeout = tmp; 1600 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout); 1601 error = 0; 1602out: 1603 icmp_mtudisc_unlock(); 1604 return error; 1605} 1606 1607static int 1608sysctl_net_inet_ip_stats(SYSCTLFN_ARGS) 1609{ 1610 1611 return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS)); 1612} 1613 1614static void 1615sysctl_net_inet_ip_setup(struct sysctllog **clog) 1616{ 1617 sysctl_createv(clog, 0, NULL, NULL, 1618 CTLFLAG_PERMANENT, 1619 CTLTYPE_NODE, "inet", 1620 SYSCTL_DESCR("PF_INET related settings"), 1621 NULL, 0, NULL, 0, 1622 CTL_NET, PF_INET, CTL_EOL); 1623 sysctl_createv(clog, 0, NULL, NULL, 1624 CTLFLAG_PERMANENT, 1625 CTLTYPE_NODE, "ip", 1626 SYSCTL_DESCR("IPv4 related settings"), 1627 NULL, 0, NULL, 0, 1628 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL); 1629 1630 sysctl_createv(clog, 0, NULL, NULL, 1631 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1632 CTLTYPE_INT, "forwarding", 1633 SYSCTL_DESCR("Enable forwarding of INET datagrams"), 1634 NULL, 0, &ipforwarding, 0, 1635 CTL_NET, PF_INET, IPPROTO_IP, 1636 IPCTL_FORWARDING, CTL_EOL); 1637 sysctl_createv(clog, 0, NULL, NULL, 1638 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1639 CTLTYPE_INT, "redirect", 1640 SYSCTL_DESCR("Enable sending of ICMP redirect messages"), 1641 NULL, 0, &ipsendredirects, 0, 1642 CTL_NET, PF_INET, IPPROTO_IP, 1643 IPCTL_SENDREDIRECTS, CTL_EOL); 1644 sysctl_createv(clog, 0, NULL, NULL, 1645 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1646 CTLTYPE_INT, "ttl", 1647 SYSCTL_DESCR("Default TTL for an INET datagram"), 1648 NULL, 0, &ip_defttl, 0, 1649 CTL_NET, PF_INET, IPPROTO_IP, 1650 IPCTL_DEFTTL, CTL_EOL); 1651#ifdef IPCTL_DEFMTU 1652 sysctl_createv(clog, 0, NULL, NULL, 1653 CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */, 1654 CTLTYPE_INT, "mtu", 1655 SYSCTL_DESCR("Default MTA for an INET route"), 1656 NULL, 0, &ip_mtu, 0, 1657 CTL_NET, PF_INET, IPPROTO_IP, 1658 IPCTL_DEFMTU, CTL_EOL); 1659#endif /* IPCTL_DEFMTU */ 1660 sysctl_createv(clog, 0, NULL, NULL, 1661 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1662 CTLTYPE_INT, "forwsrcrt", 1663 SYSCTL_DESCR("Enable forwarding of source-routed " 1664 "datagrams"), 1665 sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0, 1666 CTL_NET, PF_INET, IPPROTO_IP, 1667 IPCTL_FORWSRCRT, CTL_EOL); 1668 sysctl_createv(clog, 0, NULL, NULL, 1669 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1670 CTLTYPE_INT, "directed-broadcast", 1671 SYSCTL_DESCR("Enable forwarding of broadcast datagrams"), 1672 NULL, 0, &ip_directedbcast, 0, 1673 CTL_NET, PF_INET, IPPROTO_IP, 1674 IPCTL_DIRECTEDBCAST, CTL_EOL); 1675 sysctl_createv(clog, 0, NULL, NULL, 1676 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1677 CTLTYPE_INT, "allowsrcrt", 1678 SYSCTL_DESCR("Accept source-routed datagrams"), 1679 NULL, 0, &ip_allowsrcrt, 0, 1680 CTL_NET, PF_INET, IPPROTO_IP, 1681 IPCTL_ALLOWSRCRT, CTL_EOL); 1682 1683 sysctl_createv(clog, 0, NULL, NULL, 1684 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1685 CTLTYPE_INT, "mtudisc", 1686 SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"), 1687 NULL, 0, &ip_mtudisc, 0, 1688 CTL_NET, PF_INET, IPPROTO_IP, 1689 IPCTL_MTUDISC, CTL_EOL); 1690 sysctl_createv(clog, 0, NULL, NULL, 1691 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1692 CTLTYPE_INT, "anonportmin", 1693 SYSCTL_DESCR("Lowest ephemeral port number to assign"), 1694 sysctl_net_inet_ip_ports, 0, &anonportmin, 0, 1695 CTL_NET, PF_INET, IPPROTO_IP, 1696 IPCTL_ANONPORTMIN, CTL_EOL); 1697 sysctl_createv(clog, 0, NULL, NULL, 1698 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1699 CTLTYPE_INT, "anonportmax", 1700 SYSCTL_DESCR("Highest ephemeral port number to assign"), 1701 sysctl_net_inet_ip_ports, 0, &anonportmax, 0, 1702 CTL_NET, PF_INET, IPPROTO_IP, 1703 IPCTL_ANONPORTMAX, CTL_EOL); 1704 sysctl_createv(clog, 0, NULL, NULL, 1705 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1706 CTLTYPE_INT, "mtudisctimeout", 1707 SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"), 1708 sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0, 1709 CTL_NET, PF_INET, IPPROTO_IP, 1710 IPCTL_MTUDISCTIMEOUT, CTL_EOL); 1711#ifndef IPNOPRIVPORTS 1712 sysctl_createv(clog, 0, NULL, NULL, 1713 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1714 CTLTYPE_INT, "lowportmin", 1715 SYSCTL_DESCR("Lowest privileged ephemeral port number " 1716 "to assign"), 1717 sysctl_net_inet_ip_ports, 0, &lowportmin, 0, 1718 CTL_NET, PF_INET, IPPROTO_IP, 1719 IPCTL_LOWPORTMIN, CTL_EOL); 1720 sysctl_createv(clog, 0, NULL, NULL, 1721 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1722 CTLTYPE_INT, "lowportmax", 1723 SYSCTL_DESCR("Highest privileged ephemeral port number " 1724 "to assign"), 1725 sysctl_net_inet_ip_ports, 0, &lowportmax, 0, 1726 CTL_NET, PF_INET, IPPROTO_IP, 1727 IPCTL_LOWPORTMAX, CTL_EOL); 1728#endif /* IPNOPRIVPORTS */ 1729#if NGRE > 0 1730 sysctl_createv(clog, 0, NULL, NULL, 1731 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1732 CTLTYPE_INT, "grettl", 1733 SYSCTL_DESCR("Default TTL for a gre tunnel datagram"), 1734 NULL, 0, &ip_gre_ttl, 0, 1735 CTL_NET, PF_INET, IPPROTO_IP, 1736 IPCTL_GRE_TTL, CTL_EOL); 1737#endif /* NGRE */ 1738 sysctl_createv(clog, 0, NULL, NULL, 1739 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1740 CTLTYPE_INT, "checkinterface", 1741 SYSCTL_DESCR("Enable receive side of Strong ES model " 1742 "from RFC1122"), 1743 NULL, 0, &ip_checkinterface, 0, 1744 CTL_NET, PF_INET, IPPROTO_IP, 1745 IPCTL_CHECKINTERFACE, CTL_EOL); 1746 sysctl_createv(clog, 0, NULL, NULL, 1747 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1748 CTLTYPE_INT, "random_id", 1749 SYSCTL_DESCR("Assign random ip_id values"), 1750 NULL, 0, &ip_do_randomid, 0, 1751 CTL_NET, PF_INET, IPPROTO_IP, 1752 IPCTL_RANDOMID, CTL_EOL); 1753 sysctl_createv(clog, 0, NULL, NULL, 1754 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1755 CTLTYPE_INT, "do_loopback_cksum", 1756 SYSCTL_DESCR("Perform IP checksum on loopback"), 1757 NULL, 0, &ip_do_loopback_cksum, 0, 1758 CTL_NET, PF_INET, IPPROTO_IP, 1759 IPCTL_LOOPBACKCKSUM, CTL_EOL); 1760 sysctl_createv(clog, 0, NULL, NULL, 1761 CTLFLAG_PERMANENT, 1762 CTLTYPE_STRUCT, "stats", 1763 SYSCTL_DESCR("IP statistics"), 1764 sysctl_net_inet_ip_stats, 0, NULL, 0, 1765 CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS, 1766 CTL_EOL); 1767#if NARP 1768 sysctl_createv(clog, 0, NULL, NULL, 1769 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1770 CTLTYPE_INT, "dad_count", 1771 SYSCTL_DESCR("Number of Duplicate Address Detection " 1772 "probes to send"), 1773 NULL, 0, &ip_dad_count, 0, 1774 CTL_NET, PF_INET, IPPROTO_IP, 1775 IPCTL_DAD_COUNT, CTL_EOL); 1776#endif 1777 1778 /* anonportalgo RFC6056 subtree */ 1779 const struct sysctlnode *portalgo_node; 1780 sysctl_createv(clog, 0, NULL, &portalgo_node, 1781 CTLFLAG_PERMANENT, 1782 CTLTYPE_NODE, "anonportalgo", 1783 SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"), 1784 NULL, 0, NULL, 0, 1785 CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL); 1786 sysctl_createv(clog, 0, &portalgo_node, NULL, 1787 CTLFLAG_PERMANENT, 1788 CTLTYPE_STRING, "available", 1789 SYSCTL_DESCR("available algorithms"), 1790 sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN, 1791 CTL_CREATE, CTL_EOL); 1792 sysctl_createv(clog, 0, &portalgo_node, NULL, 1793 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1794 CTLTYPE_STRING, "selected", 1795 SYSCTL_DESCR("selected algorithm"), 1796 sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN, 1797 CTL_CREATE, CTL_EOL); 1798 sysctl_createv(clog, 0, &portalgo_node, NULL, 1799 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1800 CTLTYPE_STRUCT, "reserve", 1801 SYSCTL_DESCR("bitmap of reserved ports"), 1802 sysctl_portalgo_reserve4, 0, NULL, 0, 1803 CTL_CREATE, CTL_EOL); 1804} 1805 1806void 1807ip_statinc(u_int stat) 1808{ 1809 1810 KASSERT(stat < IP_NSTATS); 1811 IP_STATINC(stat); 1812} 1813