ip_input.c revision 1.343
1/* $NetBSD: ip_input.c,v 1.343 2016/10/18 01:15:20 ozaki-r 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 1.343 2016/10/18 01:15:20 ozaki-r Exp $"); 95 96#ifdef _KERNEL_OPT 97#include "opt_inet.h" 98#include "opt_compat_netbsd.h" 99#include "opt_gateway.h" 100#include "opt_ipsec.h" 101#include "opt_mrouting.h" 102#include "opt_mbuftrace.h" 103#include "opt_inet_csum.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 1 /* forward source-routed packets */ 165#endif 166#ifndef IPALLOWSRCRT 167#define IPALLOWSRCRT 1 /* 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#ifdef COMPAT_50 177#include <compat/sys/time.h> 178#include <compat/sys/socket.h> 179#endif 180 181/* 182 * Note: DIRECTED_BROADCAST is handled this way so that previous 183 * configuration using this option will Just Work. 184 */ 185#ifndef IPDIRECTEDBCAST 186#ifdef DIRECTED_BROADCAST 187#define IPDIRECTEDBCAST 1 188#else 189#define IPDIRECTEDBCAST 0 190#endif /* DIRECTED_BROADCAST */ 191#endif /* IPDIRECTEDBCAST */ 192int ipforwarding = IPFORWARDING; 193int ipsendredirects = IPSENDREDIRECTS; 194int ip_defttl = IPDEFTTL; 195int ip_forwsrcrt = IPFORWSRCRT; 196int ip_directedbcast = IPDIRECTEDBCAST; 197int ip_allowsrcrt = IPALLOWSRCRT; 198int ip_mtudisc = IPMTUDISC; 199int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 200#ifdef DIAGNOSTIC 201int ipprintfs = 0; 202#endif 203 204int ip_do_randomid = 0; 205 206/* 207 * XXX - Setting ip_checkinterface mostly implements the receive side of 208 * the Strong ES model described in RFC 1122, but since the routing table 209 * and transmit implementation do not implement the Strong ES model, 210 * setting this to 1 results in an odd hybrid. 211 * 212 * XXX - ip_checkinterface currently must be disabled if you use ipnat 213 * to translate the destination address to another local interface. 214 * 215 * XXX - ip_checkinterface must be disabled if you add IP aliases 216 * to the loopback interface instead of the interface where the 217 * packets for those addresses are received. 218 */ 219static int ip_checkinterface __read_mostly = 0; 220 221struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 222 223pktqueue_t * ip_pktq __read_mostly; 224pfil_head_t * inet_pfil_hook __read_mostly; 225ipid_state_t * ip_ids __read_mostly; 226percpu_t * ipstat_percpu __read_mostly; 227 228static percpu_t *ipforward_rt_percpu __cacheline_aligned; 229 230uint16_t ip_id; 231 232#ifdef INET_CSUM_COUNTERS 233#include <sys/device.h> 234 235struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 236 NULL, "inet", "hwcsum bad"); 237struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 238 NULL, "inet", "hwcsum ok"); 239struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 240 NULL, "inet", "swcsum"); 241 242#define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 243 244EVCNT_ATTACH_STATIC(ip_hwcsum_bad); 245EVCNT_ATTACH_STATIC(ip_hwcsum_ok); 246EVCNT_ATTACH_STATIC(ip_swcsum); 247 248#else 249 250#define INET_CSUM_COUNTER_INCR(ev) /* nothing */ 251 252#endif /* INET_CSUM_COUNTERS */ 253 254/* 255 * We need to save the IP options in case a protocol wants to respond 256 * to an incoming packet over the same route if the packet got here 257 * using IP source routing. This allows connection establishment and 258 * maintenance when the remote end is on a network that is not known 259 * to us. 260 */ 261 262static int ip_nhops = 0; 263 264static struct ip_srcrt { 265 struct in_addr dst; /* final destination */ 266 char nop; /* one NOP to align */ 267 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 268 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 269} ip_srcrt; 270 271static int ip_drainwanted; 272 273struct sockaddr_in ipaddr = { 274 .sin_len = sizeof(ipaddr), 275 .sin_family = AF_INET, 276}; 277 278static void save_rte(u_char *, struct in_addr); 279 280#ifdef MBUFTRACE 281struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx"); 282struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx"); 283#endif 284 285static void ipintr(void *); 286static void ip_input(struct mbuf *); 287static void ip_forward(struct mbuf *, int, struct ifnet *); 288static bool ip_dooptions(struct mbuf *); 289static struct in_ifaddr *ip_rtaddr(struct in_addr); 290static void sysctl_net_inet_ip_setup(struct sysctllog **); 291 292static struct in_ifaddr *ip_match_our_address(struct ifnet *, struct ip *, 293 int *); 294static struct in_ifaddr *ip_match_our_address_broadcast(struct ifnet *, 295 struct ip *); 296 297/* XXX: Not yet enabled. */ 298#define SOFTNET_LOCK() KASSERT(mutex_owned(softnet_lock)) 299#define SOFTNET_UNLOCK() KASSERT(mutex_owned(softnet_lock)) 300 301/* 302 * IP initialization: fill in IP protocol switch table. 303 * All protocols not implemented in kernel go to raw IP protocol handler. 304 */ 305void 306ip_init(void) 307{ 308 const struct protosw *pr; 309 310 in_init(); 311 sysctl_net_inet_ip_setup(NULL); 312 313 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 314 KASSERT(pr != NULL); 315 316 ip_pktq = pktq_create(IFQ_MAXLEN, ipintr, NULL); 317 KASSERT(ip_pktq != NULL); 318 319 for (u_int i = 0; i < IPPROTO_MAX; i++) { 320 ip_protox[i] = pr - inetsw; 321 } 322 for (pr = inetdomain.dom_protosw; 323 pr < inetdomain.dom_protoswNPROTOSW; pr++) 324 if (pr->pr_domain->dom_family == PF_INET && 325 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 326 ip_protox[pr->pr_protocol] = pr - inetsw; 327 328 ip_reass_init(); 329 330 ip_ids = ip_id_init(); 331 ip_id = time_uptime & 0xfffff; 332 333 ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout); 334#ifdef GATEWAY 335 ipflow_init(); 336#endif 337 338 /* Register our Packet Filter hook. */ 339 inet_pfil_hook = pfil_head_create(PFIL_TYPE_AF, (void *)AF_INET); 340 KASSERT(inet_pfil_hook != NULL); 341 342#ifdef MBUFTRACE 343 MOWNER_ATTACH(&ip_tx_mowner); 344 MOWNER_ATTACH(&ip_rx_mowner); 345#endif /* MBUFTRACE */ 346 347 ipstat_percpu = percpu_alloc(sizeof(uint64_t) * IP_NSTATS); 348 349 ipforward_rt_percpu = percpu_alloc(sizeof(struct route)); 350 if (ipforward_rt_percpu == NULL) 351 panic("failed to allocate ipforward_rt_percpu"); 352} 353 354static struct in_ifaddr * 355ip_match_our_address(struct ifnet *ifp, struct ip *ip, int *downmatch) 356{ 357 struct in_ifaddr *ia = NULL; 358 int checkif; 359 360 /* 361 * Enable a consistency check between the destination address 362 * and the arrival interface for a unicast packet (the RFC 1122 363 * strong ES model) if IP forwarding is disabled and the packet 364 * is not locally generated. 365 * 366 * XXX - Checking also should be disabled if the destination 367 * address is ipnat'ed to a different interface. 368 * 369 * XXX - Checking is incompatible with IP aliases added 370 * to the loopback interface instead of the interface where 371 * the packets are received. 372 * 373 * XXX - We need to add a per ifaddr flag for this so that 374 * we get finer grain control. 375 */ 376 checkif = ip_checkinterface && (ipforwarding == 0) && 377 (ifp->if_flags & IFF_LOOPBACK) == 0; 378 379 IN_ADDRHASH_READER_FOREACH(ia, ip->ip_dst.s_addr) { 380 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) { 381 if (ia->ia4_flags & IN_IFF_NOTREADY) 382 continue; 383 if (checkif && ia->ia_ifp != ifp) 384 continue; 385 if ((ia->ia_ifp->if_flags & IFF_UP) != 0 && 386 (ia->ia4_flags & IN_IFF_DETACHED) == 0) 387 break; 388 else 389 (*downmatch)++; 390 } 391 } 392 393 return ia; 394} 395 396static struct in_ifaddr * 397ip_match_our_address_broadcast(struct ifnet *ifp, struct ip *ip) 398{ 399 struct in_ifaddr *ia = NULL; 400 struct ifaddr *ifa; 401 402 IFADDR_READER_FOREACH(ifa, ifp) { 403 if (ifa->ifa_addr->sa_family != AF_INET) 404 continue; 405 ia = ifatoia(ifa); 406 if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED)) 407 continue; 408 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 409 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 410 /* 411 * Look for all-0's host part (old broadcast addr), 412 * either for subnet or net. 413 */ 414 ip->ip_dst.s_addr == ia->ia_subnet || 415 ip->ip_dst.s_addr == ia->ia_net) 416 goto matched; 417 /* 418 * An interface with IP address zero accepts 419 * all packets that arrive on that interface. 420 */ 421 if (in_nullhost(ia->ia_addr.sin_addr)) 422 goto matched; 423 } 424 ia = NULL; 425 426matched: 427 return ia; 428} 429 430/* 431 * IP software interrupt routine. 432 */ 433static void 434ipintr(void *arg __unused) 435{ 436 struct mbuf *m; 437 438 KASSERT(cpu_softintr_p()); 439 440 mutex_enter(softnet_lock); 441 while ((m = pktq_dequeue(ip_pktq)) != NULL) { 442 ip_input(m); 443 } 444 mutex_exit(softnet_lock); 445} 446 447/* 448 * IP input routine. Checksum and byte swap header. If fragmented 449 * try to reassemble. Process options. Pass to next level. 450 */ 451static void 452ip_input(struct mbuf *m) 453{ 454 struct ip *ip = NULL; 455 struct in_ifaddr *ia = NULL; 456 int hlen = 0, len; 457 int downmatch; 458 int srcrt = 0; 459 ifnet_t *ifp; 460 struct psref psref; 461 int s; 462 463 KASSERTMSG(cpu_softintr_p(), "ip_input: not in the software " 464 "interrupt handler; synchronization assumptions violated"); 465 466 MCLAIM(m, &ip_rx_mowner); 467 KASSERT((m->m_flags & M_PKTHDR) != 0); 468 469 ifp = m_get_rcvif_psref(m, &psref); 470 if (__predict_false(ifp == NULL)) 471 goto out; 472 473 /* 474 * If no IP addresses have been set yet but the interfaces 475 * are receiving, can't do anything with incoming packets yet. 476 * Note: we pre-check without locks held. 477 */ 478 if (IN_ADDRLIST_READER_EMPTY()) 479 goto out; 480 IP_STATINC(IP_STAT_TOTAL); 481 482 /* 483 * If the IP header is not aligned, slurp it up into a new 484 * mbuf with space for link headers, in the event we forward 485 * it. Otherwise, if it is aligned, make sure the entire 486 * base IP header is in the first mbuf of the chain. 487 */ 488 if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) { 489 if ((m = m_copyup(m, sizeof(struct ip), 490 (max_linkhdr + 3) & ~3)) == NULL) { 491 /* XXXJRT new stat, please */ 492 IP_STATINC(IP_STAT_TOOSMALL); 493 goto out; 494 } 495 } else if (__predict_false(m->m_len < sizeof (struct ip))) { 496 if ((m = m_pullup(m, sizeof (struct ip))) == NULL) { 497 IP_STATINC(IP_STAT_TOOSMALL); 498 goto out; 499 } 500 } 501 ip = mtod(m, struct ip *); 502 if (ip->ip_v != IPVERSION) { 503 IP_STATINC(IP_STAT_BADVERS); 504 goto out; 505 } 506 hlen = ip->ip_hl << 2; 507 if (hlen < sizeof(struct ip)) { /* minimum header length */ 508 IP_STATINC(IP_STAT_BADHLEN); 509 goto out; 510 } 511 if (hlen > m->m_len) { 512 if ((m = m_pullup(m, hlen)) == NULL) { 513 IP_STATINC(IP_STAT_BADHLEN); 514 goto out; 515 } 516 ip = mtod(m, struct ip *); 517 } 518 519 /* 520 * RFC1122: packets with a multicast source address are 521 * not allowed. 522 */ 523 if (IN_MULTICAST(ip->ip_src.s_addr)) { 524 IP_STATINC(IP_STAT_BADADDR); 525 goto out; 526 } 527 528 /* 127/8 must not appear on wire - RFC1122 */ 529 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 530 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 531 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 532 IP_STATINC(IP_STAT_BADADDR); 533 goto out; 534 } 535 } 536 537 switch (m->m_pkthdr.csum_flags & 538 ((ifp->if_csum_flags_rx & M_CSUM_IPv4) | 539 M_CSUM_IPv4_BAD)) { 540 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 541 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad); 542 IP_STATINC(IP_STAT_BADSUM); 543 goto out; 544 545 case M_CSUM_IPv4: 546 /* Checksum was okay. */ 547 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok); 548 break; 549 550 default: 551 /* 552 * Must compute it ourselves. Maybe skip checksum on 553 * loopback interfaces. 554 */ 555 if (__predict_true(!(ifp->if_flags & IFF_LOOPBACK) || 556 ip_do_loopback_cksum)) { 557 INET_CSUM_COUNTER_INCR(&ip_swcsum); 558 if (in_cksum(m, hlen) != 0) { 559 IP_STATINC(IP_STAT_BADSUM); 560 goto out; 561 } 562 } 563 break; 564 } 565 566 /* Retrieve the packet length. */ 567 len = ntohs(ip->ip_len); 568 569 /* 570 * Check for additional length bogosity 571 */ 572 if (len < hlen) { 573 IP_STATINC(IP_STAT_BADLEN); 574 goto out; 575 } 576 577 /* 578 * Check that the amount of data in the buffers 579 * is as at least much as the IP header would have us expect. 580 * Trim mbufs if longer than we expect. 581 * Drop packet if shorter than we expect. 582 */ 583 if (m->m_pkthdr.len < len) { 584 IP_STATINC(IP_STAT_TOOSHORT); 585 goto out; 586 } 587 if (m->m_pkthdr.len > len) { 588 if (m->m_len == m->m_pkthdr.len) { 589 m->m_len = len; 590 m->m_pkthdr.len = len; 591 } else 592 m_adj(m, len - m->m_pkthdr.len); 593 } 594 595 /* 596 * Assume that we can create a fast-forward IP flow entry 597 * based on this packet. 598 */ 599 m->m_flags |= M_CANFASTFWD; 600 601 /* 602 * Run through list of hooks for input packets. If there are any 603 * filters which require that additional packets in the flow are 604 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 605 * Note that filters must _never_ set this flag, as another filter 606 * in the list may have previously cleared it. 607 */ 608#if defined(IPSEC) 609 if (!ipsec_used || !ipsec_indone(m)) 610#else 611 if (1) 612#endif 613 { 614 struct in_addr odst = ip->ip_dst; 615 bool freed; 616 617 SOFTNET_LOCK(); 618 freed = pfil_run_hooks(inet_pfil_hook, &m, ifp, PFIL_IN) != 0; 619 SOFTNET_UNLOCK(); 620 if (freed || m == NULL) { 621 m = NULL; 622 goto out; 623 } 624 ip = mtod(m, struct ip *); 625 hlen = ip->ip_hl << 2; 626 627 /* 628 * XXX The setting of "srcrt" here is to prevent ip_forward() 629 * from generating ICMP redirects for packets that have 630 * been redirected by a hook back out on to the same LAN that 631 * they came from and is not an indication that the packet 632 * is being inffluenced by source routing options. This 633 * allows things like 634 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp" 635 * where tlp0 is both on the 1.1.1.0/24 network and is the 636 * default route for hosts on 1.1.1.0/24. Of course this 637 * also requires a "map tlp0 ..." to complete the story. 638 * One might argue whether or not this kind of network config. 639 * should be supported in this manner... 640 */ 641 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 642 } 643 644#ifdef ALTQ 645 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 646 if (altq_input) { 647 SOFTNET_LOCK(); 648 if ((*altq_input)(m, AF_INET) == 0) { 649 /* Packet dropped by traffic conditioner. */ 650 SOFTNET_UNLOCK(); 651 m = NULL; 652 goto out; 653 } 654 SOFTNET_UNLOCK(); 655 } 656#endif 657 658 /* 659 * Process options and, if not destined for us, 660 * ship it on. ip_dooptions returns 1 when an 661 * error was detected (causing an icmp message 662 * to be sent and the original packet to be freed). 663 */ 664 ip_nhops = 0; /* for source routed packets */ 665 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 666 m = NULL; 667 goto out; 668 } 669 670 /* 671 * Check our list of addresses, to see if the packet is for us. 672 * 673 * Traditional 4.4BSD did not consult IFF_UP at all. 674 * The behavior here is to treat addresses on !IFF_UP interface 675 * or IN_IFF_NOTREADY addresses as not mine. 676 */ 677 downmatch = 0; 678 s = pserialize_read_enter(); 679 ia = ip_match_our_address(ifp, ip, &downmatch); 680 if (ia != NULL) { 681 pserialize_read_exit(s); 682 goto ours; 683 } 684 685 if (ifp->if_flags & IFF_BROADCAST) { 686 ia = ip_match_our_address_broadcast(ifp, ip); 687 if (ia != NULL) { 688 pserialize_read_exit(s); 689 goto ours; 690 } 691 } 692 pserialize_read_exit(s); 693 694 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 695#ifdef MROUTING 696 extern struct socket *ip_mrouter; 697 698 if (ip_mrouter) { 699 /* 700 * If we are acting as a multicast router, all 701 * incoming multicast packets are passed to the 702 * kernel-level multicast forwarding function. 703 * The packet is returned (relatively) intact; if 704 * ip_mforward() returns a non-zero value, the packet 705 * must be discarded, else it may be accepted below. 706 * 707 * (The IP ident field is put in the same byte order 708 * as expected when ip_mforward() is called from 709 * ip_output().) 710 */ 711 SOFTNET_LOCK(); 712 if (ip_mforward(m, ifp) != 0) { 713 SOFTNET_UNLOCK(); 714 IP_STATINC(IP_STAT_CANTFORWARD); 715 goto out; 716 } 717 SOFTNET_UNLOCK(); 718 719 /* 720 * The process-level routing demon needs to receive 721 * all multicast IGMP packets, whether or not this 722 * host belongs to their destination groups. 723 */ 724 if (ip->ip_p == IPPROTO_IGMP) { 725 goto ours; 726 } 727 IP_STATINC(IP_STAT_CANTFORWARD); 728 } 729#endif 730 /* 731 * See if we belong to the destination multicast group on the 732 * arrival interface. 733 */ 734 if (!in_multi_group(ip->ip_dst, ifp, 0)) { 735 IP_STATINC(IP_STAT_CANTFORWARD); 736 goto out; 737 } 738 goto ours; 739 } 740 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 741 in_nullhost(ip->ip_dst)) 742 goto ours; 743 744 /* 745 * Not for us; forward if possible and desirable. 746 */ 747 if (ipforwarding == 0) { 748 m_put_rcvif_psref(ifp, &psref); 749 IP_STATINC(IP_STAT_CANTFORWARD); 750 m_freem(m); 751 } else { 752 /* 753 * If ip_dst matched any of my address on !IFF_UP interface, 754 * and there's no IFF_UP interface that matches ip_dst, 755 * send icmp unreach. Forwarding it will result in in-kernel 756 * forwarding loop till TTL goes to 0. 757 */ 758 if (downmatch) { 759 m_put_rcvif_psref(ifp, &psref); 760 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 761 IP_STATINC(IP_STAT_CANTFORWARD); 762 return; 763 } 764#ifdef IPSEC 765 /* Perform IPsec, if any. */ 766 if (ipsec_used) { 767 SOFTNET_LOCK(); 768 if (ipsec4_input(m, IP_FORWARDING | 769 (ip_directedbcast ? IP_ALLOWBROADCAST : 0)) != 0) { 770 SOFTNET_UNLOCK(); 771 goto out; 772 } 773 SOFTNET_UNLOCK(); 774 } 775#endif 776 ip_forward(m, srcrt, ifp); 777 m_put_rcvif_psref(ifp, &psref); 778 } 779 return; 780 781ours: 782 m_put_rcvif_psref(ifp, &psref); 783 ifp = NULL; 784 785 /* 786 * If offset or IP_MF are set, must reassemble. 787 */ 788 if (ip->ip_off & ~htons(IP_DF|IP_RF)) { 789 /* 790 * Pass to IP reassembly mechanism. 791 */ 792 if (ip_reass_packet(&m, ip) != 0) { 793 /* Failed; invalid fragment(s) or packet. */ 794 goto out; 795 } 796 if (m == NULL) { 797 /* More fragments should come; silently return. */ 798 goto out; 799 } 800 /* 801 * Reassembly is done, we have the final packet. 802 * Updated cached data in local variable(s). 803 */ 804 ip = mtod(m, struct ip *); 805 hlen = ip->ip_hl << 2; 806 } 807 808#ifdef IPSEC 809 /* 810 * Enforce IPsec policy checking if we are seeing last header. 811 * Note that we do not visit this with protocols with PCB layer 812 * code - like UDP/TCP/raw IP. 813 */ 814 if (ipsec_used && 815 (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 816 SOFTNET_LOCK(); 817 if (ipsec4_input(m, 0) != 0) { 818 SOFTNET_UNLOCK(); 819 goto out; 820 } 821 SOFTNET_UNLOCK(); 822 } 823#endif 824 825 /* 826 * Switch out to protocol's input routine. 827 */ 828#if IFA_STATS 829 if (ia && ip) { 830 struct in_ifaddr *_ia; 831 /* 832 * Keep a reference from ip_match_our_address with psref 833 * is expensive, so explore ia here again. 834 */ 835 s = pserialize_read_enter(); 836 _ia = in_get_ia(ip->ip_dst); 837 _ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len); 838 pserialize_read_exit(s); 839 } 840#endif 841 IP_STATINC(IP_STAT_DELIVERED); 842 843 const int off = hlen, nh = ip->ip_p; 844 845 SOFTNET_LOCK(); 846 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 847 SOFTNET_UNLOCK(); 848 return; 849 850out: 851 m_put_rcvif_psref(ifp, &psref); 852 if (m != NULL) 853 m_freem(m); 854} 855 856/* 857 * IP timer processing. 858 */ 859void 860ip_slowtimo(void) 861{ 862 863 mutex_enter(softnet_lock); 864 KERNEL_LOCK(1, NULL); 865 866 ip_reass_slowtimo(); 867 868 KERNEL_UNLOCK_ONE(NULL); 869 mutex_exit(softnet_lock); 870} 871 872/* 873 * IP drain processing. 874 */ 875void 876ip_drain(void) 877{ 878 879 KERNEL_LOCK(1, NULL); 880 ip_reass_drain(); 881 KERNEL_UNLOCK_ONE(NULL); 882} 883 884/* 885 * ip_dooptions: perform option processing on a datagram, possibly discarding 886 * it if bad options are encountered, or forwarding it if source-routed. 887 * 888 * => Returns true if packet has been forwarded/freed. 889 * => Returns false if the packet should be processed further. 890 */ 891static bool 892ip_dooptions(struct mbuf *m) 893{ 894 struct ip *ip = mtod(m, struct ip *); 895 u_char *cp, *cp0; 896 struct ip_timestamp *ipt; 897 struct in_ifaddr *ia; 898 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 899 struct in_addr dst; 900 n_time ntime; 901 struct ifaddr *ifa; 902 int s; 903 904 dst = ip->ip_dst; 905 cp = (u_char *)(ip + 1); 906 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 907 for (; cnt > 0; cnt -= optlen, cp += optlen) { 908 opt = cp[IPOPT_OPTVAL]; 909 if (opt == IPOPT_EOL) 910 break; 911 if (opt == IPOPT_NOP) 912 optlen = 1; 913 else { 914 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 915 code = &cp[IPOPT_OLEN] - (u_char *)ip; 916 goto bad; 917 } 918 optlen = cp[IPOPT_OLEN]; 919 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 920 code = &cp[IPOPT_OLEN] - (u_char *)ip; 921 goto bad; 922 } 923 } 924 switch (opt) { 925 926 default: 927 break; 928 929 /* 930 * Source routing with record. 931 * Find interface with current destination address. 932 * If none on this machine then drop if strictly routed, 933 * or do nothing if loosely routed. 934 * Record interface address and bring up next address 935 * component. If strictly routed make sure next 936 * address is on directly accessible net. 937 */ 938 case IPOPT_LSRR: 939 case IPOPT_SSRR: 940 if (ip_allowsrcrt == 0) { 941 type = ICMP_UNREACH; 942 code = ICMP_UNREACH_NET_PROHIB; 943 goto bad; 944 } 945 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 946 code = &cp[IPOPT_OLEN] - (u_char *)ip; 947 goto bad; 948 } 949 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 950 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 951 goto bad; 952 } 953 ipaddr.sin_addr = ip->ip_dst; 954 955 s = pserialize_read_enter(); 956 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 957 if (ifa == NULL) { 958 pserialize_read_exit(s); 959 if (opt == IPOPT_SSRR) { 960 type = ICMP_UNREACH; 961 code = ICMP_UNREACH_SRCFAIL; 962 goto bad; 963 } 964 /* 965 * Loose routing, and not at next destination 966 * yet; nothing to do except forward. 967 */ 968 break; 969 } 970 pserialize_read_exit(s); 971 972 off--; /* 0 origin */ 973 if ((off + sizeof(struct in_addr)) > optlen) { 974 /* 975 * End of source route. Should be for us. 976 */ 977 save_rte(cp, ip->ip_src); 978 break; 979 } 980 /* 981 * locate outgoing interface 982 */ 983 memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off), 984 sizeof(ipaddr.sin_addr)); 985 s = pserialize_read_enter(); 986 if (opt == IPOPT_SSRR) { 987 ifa = ifa_ifwithladdr(sintosa(&ipaddr)); 988 if (ifa != NULL) 989 ia = ifatoia(ifa); 990 else 991 ia = NULL; 992 } else { 993 ia = ip_rtaddr(ipaddr.sin_addr); 994 } 995 if (ia == NULL) { 996 type = ICMP_UNREACH; 997 code = ICMP_UNREACH_SRCFAIL; 998 pserialize_read_exit(s); 999 goto bad; 1000 } 1001 ip->ip_dst = ipaddr.sin_addr; 1002 bcopy((void *)&ia->ia_addr.sin_addr, 1003 (void *)(cp + off), sizeof(struct in_addr)); 1004 pserialize_read_exit(s); 1005 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1006 /* 1007 * Let ip_intr's mcast routing check handle mcast pkts 1008 */ 1009 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1010 break; 1011 1012 case IPOPT_RR: 1013 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1014 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1015 goto bad; 1016 } 1017 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1018 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1019 goto bad; 1020 } 1021 /* 1022 * If no space remains, ignore. 1023 */ 1024 off--; /* 0 origin */ 1025 if ((off + sizeof(struct in_addr)) > optlen) 1026 break; 1027 memcpy((void *)&ipaddr.sin_addr, (void *)(&ip->ip_dst), 1028 sizeof(ipaddr.sin_addr)); 1029 /* 1030 * locate outgoing interface; if we're the destination, 1031 * use the incoming interface (should be same). 1032 */ 1033 s = pserialize_read_enter(); 1034 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 1035 if (ifa == NULL) { 1036 ia = ip_rtaddr(ipaddr.sin_addr); 1037 if (ia == NULL) { 1038 pserialize_read_exit(s); 1039 type = ICMP_UNREACH; 1040 code = ICMP_UNREACH_HOST; 1041 goto bad; 1042 } 1043 } else { 1044 ia = ifatoia(ifa); 1045 } 1046 bcopy((void *)&ia->ia_addr.sin_addr, 1047 (void *)(cp + off), sizeof(struct in_addr)); 1048 pserialize_read_exit(s); 1049 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1050 break; 1051 1052 case IPOPT_TS: 1053 code = cp - (u_char *)ip; 1054 ipt = (struct ip_timestamp *)cp; 1055 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1056 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1057 goto bad; 1058 } 1059 if (ipt->ipt_ptr < 5) { 1060 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1061 goto bad; 1062 } 1063 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) { 1064 if (++ipt->ipt_oflw == 0) { 1065 code = (u_char *)&ipt->ipt_ptr - 1066 (u_char *)ip; 1067 goto bad; 1068 } 1069 break; 1070 } 1071 cp0 = (cp + ipt->ipt_ptr - 1); 1072 switch (ipt->ipt_flg) { 1073 1074 case IPOPT_TS_TSONLY: 1075 break; 1076 1077 case IPOPT_TS_TSANDADDR: { 1078 struct ifnet *rcvif; 1079 int _s, _ss; 1080 1081 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1082 sizeof(struct in_addr) > ipt->ipt_len) { 1083 code = (u_char *)&ipt->ipt_ptr - 1084 (u_char *)ip; 1085 goto bad; 1086 } 1087 ipaddr.sin_addr = dst; 1088 _ss = pserialize_read_enter(); 1089 rcvif = m_get_rcvif(m, &_s); 1090 ifa = ifaof_ifpforaddr(sintosa(&ipaddr), rcvif); 1091 m_put_rcvif(rcvif, &_s); 1092 if (ifa == NULL) { 1093 pserialize_read_exit(_ss); 1094 break; 1095 } 1096 ia = ifatoia(ifa); 1097 bcopy(&ia->ia_addr.sin_addr, 1098 cp0, sizeof(struct in_addr)); 1099 pserialize_read_exit(_ss); 1100 ipt->ipt_ptr += sizeof(struct in_addr); 1101 break; 1102 } 1103 1104 case IPOPT_TS_PRESPEC: 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 default: 1124 /* XXX can't take &ipt->ipt_flg */ 1125 code = (u_char *)&ipt->ipt_ptr - 1126 (u_char *)ip + 1; 1127 goto bad; 1128 } 1129 ntime = iptime(); 1130 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1131 memmove((char *)cp + ipt->ipt_ptr - 1, cp0, 1132 sizeof(n_time)); 1133 ipt->ipt_ptr += sizeof(n_time); 1134 } 1135 } 1136 if (forward) { 1137 struct ifnet *rcvif; 1138 struct psref _psref; 1139 1140 if (ip_forwsrcrt == 0) { 1141 type = ICMP_UNREACH; 1142 code = ICMP_UNREACH_SRCFAIL; 1143 goto bad; 1144 } 1145 1146 rcvif = m_get_rcvif_psref(m, &_psref); 1147 if (__predict_false(rcvif == NULL)) { 1148 type = ICMP_UNREACH; 1149 code = ICMP_UNREACH_HOST; 1150 goto bad; 1151 } 1152 ip_forward(m, 1, rcvif); 1153 m_put_rcvif_psref(rcvif, &_psref); 1154 return true; 1155 } 1156 return false; 1157bad: 1158 icmp_error(m, type, code, 0, 0); 1159 IP_STATINC(IP_STAT_BADOPTIONS); 1160 return true; 1161} 1162 1163/* 1164 * ip_rtaddr: given address of next destination (final or next hop), 1165 * return internet address info of interface to be used to get there. 1166 */ 1167static struct in_ifaddr * 1168ip_rtaddr(struct in_addr dst) 1169{ 1170 struct rtentry *rt; 1171 union { 1172 struct sockaddr dst; 1173 struct sockaddr_in dst4; 1174 } u; 1175 struct route *ro; 1176 1177 sockaddr_in_init(&u.dst4, &dst, 0); 1178 1179 SOFTNET_LOCK(); 1180 ro = percpu_getref(ipforward_rt_percpu); 1181 rt = rtcache_lookup(ro, &u.dst); 1182 percpu_putref(ipforward_rt_percpu); 1183 SOFTNET_UNLOCK(); 1184 if (rt == NULL) 1185 return NULL; 1186 1187 return ifatoia(rt->rt_ifa); 1188} 1189 1190/* 1191 * save_rte: save incoming source route for use in replies, to be picked 1192 * up later by ip_srcroute if the receiver is interested. 1193 */ 1194static void 1195save_rte(u_char *option, struct in_addr dst) 1196{ 1197 unsigned olen; 1198 1199 olen = option[IPOPT_OLEN]; 1200 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1201 return; 1202 memcpy((void *)ip_srcrt.srcopt, (void *)option, olen); 1203 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1204 ip_srcrt.dst = dst; 1205} 1206 1207/* 1208 * Retrieve incoming source route for use in replies, 1209 * in the same form used by setsockopt. 1210 * The first hop is placed before the options, will be removed later. 1211 */ 1212struct mbuf * 1213ip_srcroute(void) 1214{ 1215 struct in_addr *p, *q; 1216 struct mbuf *m; 1217 1218 if (ip_nhops == 0) 1219 return NULL; 1220 m = m_get(M_DONTWAIT, MT_SOOPTS); 1221 if (m == 0) 1222 return NULL; 1223 1224 MCLAIM(m, &inetdomain.dom_mowner); 1225#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1226 1227 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1228 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1229 OPTSIZ; 1230 1231 /* 1232 * First save first hop for return route 1233 */ 1234 p = &ip_srcrt.route[ip_nhops - 1]; 1235 *(mtod(m, struct in_addr *)) = *p--; 1236 1237 /* 1238 * Copy option fields and padding (nop) to mbuf. 1239 */ 1240 ip_srcrt.nop = IPOPT_NOP; 1241 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1242 memmove(mtod(m, char *) + sizeof(struct in_addr), &ip_srcrt.nop, 1243 OPTSIZ); 1244 q = (struct in_addr *)(mtod(m, char *) + 1245 sizeof(struct in_addr) + OPTSIZ); 1246#undef OPTSIZ 1247 /* 1248 * Record return path as an IP source route, 1249 * reversing the path (pointers are now aligned). 1250 */ 1251 while (p >= ip_srcrt.route) { 1252 *q++ = *p--; 1253 } 1254 /* 1255 * Last hop goes to final destination. 1256 */ 1257 *q = ip_srcrt.dst; 1258 return (m); 1259} 1260 1261const int inetctlerrmap[PRC_NCMDS] = { 1262 [PRC_MSGSIZE] = EMSGSIZE, 1263 [PRC_HOSTDEAD] = EHOSTDOWN, 1264 [PRC_HOSTUNREACH] = EHOSTUNREACH, 1265 [PRC_UNREACH_NET] = EHOSTUNREACH, 1266 [PRC_UNREACH_HOST] = EHOSTUNREACH, 1267 [PRC_UNREACH_PROTOCOL] = ECONNREFUSED, 1268 [PRC_UNREACH_PORT] = ECONNREFUSED, 1269 [PRC_UNREACH_SRCFAIL] = EHOSTUNREACH, 1270 [PRC_PARAMPROB] = ENOPROTOOPT, 1271}; 1272 1273void 1274ip_fasttimo(void) 1275{ 1276 if (ip_drainwanted) { 1277 ip_drain(); 1278 ip_drainwanted = 0; 1279 } 1280} 1281 1282void 1283ip_drainstub(void) 1284{ 1285 ip_drainwanted = 1; 1286} 1287 1288/* 1289 * Forward a packet. If some error occurs return the sender 1290 * an icmp packet. Note we can't always generate a meaningful 1291 * icmp message because icmp doesn't have a large enough repertoire 1292 * of codes and types. 1293 * 1294 * If not forwarding, just drop the packet. This could be confusing 1295 * if ipforwarding was zero but some routing protocol was advancing 1296 * us as a gateway to somewhere. However, we must let the routing 1297 * protocol deal with that. 1298 * 1299 * The srcrt parameter indicates whether the packet is being forwarded 1300 * via a source route. 1301 */ 1302static void 1303ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif) 1304{ 1305 struct ip *ip = mtod(m, struct ip *); 1306 struct rtentry *rt; 1307 int error, type = 0, code = 0, destmtu = 0; 1308 struct mbuf *mcopy; 1309 n_long dest; 1310 union { 1311 struct sockaddr dst; 1312 struct sockaddr_in dst4; 1313 } u; 1314 uint64_t *ips; 1315 struct route *ro; 1316 1317 KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software " 1318 "interrupt handler; synchronization assumptions violated"); 1319 1320 /* 1321 * We are now in the output path. 1322 */ 1323 MCLAIM(m, &ip_tx_mowner); 1324 1325 /* 1326 * Clear any in-bound checksum flags for this packet. 1327 */ 1328 m->m_pkthdr.csum_flags = 0; 1329 1330 dest = 0; 1331 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1332 IP_STATINC(IP_STAT_CANTFORWARD); 1333 m_freem(m); 1334 return; 1335 } 1336 1337 SOFTNET_LOCK(); 1338 1339 if (ip->ip_ttl <= IPTTLDEC) { 1340 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1341 SOFTNET_UNLOCK(); 1342 return; 1343 } 1344 1345 sockaddr_in_init(&u.dst4, &ip->ip_dst, 0); 1346 1347 ro = percpu_getref(ipforward_rt_percpu); 1348 if ((rt = rtcache_lookup(ro, &u.dst)) == NULL) { 1349 percpu_putref(ipforward_rt_percpu); 1350 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0); 1351 SOFTNET_UNLOCK(); 1352 return; 1353 } 1354 1355 /* 1356 * Save at most 68 bytes of the packet in case 1357 * we need to generate an ICMP message to the src. 1358 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1359 */ 1360 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1361 if (mcopy) 1362 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1363 1364 ip->ip_ttl -= IPTTLDEC; 1365 1366 /* 1367 * If forwarding packet using same interface that it came in on, 1368 * perhaps should send a redirect to sender to shortcut a hop. 1369 * Only send redirect if source is sending directly to us, 1370 * and if packet was not source routed (or has any options). 1371 * Also, don't send redirect if forwarding using a default route 1372 * or a route modified by a redirect. 1373 */ 1374 if (rt->rt_ifp == rcvif && 1375 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1376 !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) && 1377 ipsendredirects && !srcrt) { 1378 if (rt->rt_ifa && 1379 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1380 ifatoia(rt->rt_ifa)->ia_subnet) { 1381 if (rt->rt_flags & RTF_GATEWAY) 1382 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1383 else 1384 dest = ip->ip_dst.s_addr; 1385 /* 1386 * Router requirements says to only send host 1387 * redirects. 1388 */ 1389 type = ICMP_REDIRECT; 1390 code = ICMP_REDIRECT_HOST; 1391 } 1392 } 1393 1394 error = ip_output(m, NULL, ro, 1395 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1396 NULL, NULL); 1397 1398 if (error) { 1399 IP_STATINC(IP_STAT_CANTFORWARD); 1400 goto error; 1401 } 1402 1403 ips = IP_STAT_GETREF(); 1404 ips[IP_STAT_FORWARD]++; 1405 1406 if (type) { 1407 ips[IP_STAT_REDIRECTSENT]++; 1408 IP_STAT_PUTREF(); 1409 goto redirect; 1410 } 1411 1412 IP_STAT_PUTREF(); 1413 if (mcopy) { 1414#ifdef GATEWAY 1415 if (mcopy->m_flags & M_CANFASTFWD) 1416 ipflow_create(ro, mcopy); 1417#endif 1418 m_freem(mcopy); 1419 } 1420 1421 percpu_putref(ipforward_rt_percpu); 1422 SOFTNET_UNLOCK(); 1423 return; 1424 1425redirect: 1426error: 1427 if (mcopy == NULL) { 1428 percpu_putref(ipforward_rt_percpu); 1429 SOFTNET_UNLOCK(); 1430 return; 1431 } 1432 1433 switch (error) { 1434 1435 case 0: /* forwarded, but need redirect */ 1436 /* type, code set above */ 1437 break; 1438 1439 case ENETUNREACH: /* shouldn't happen, checked above */ 1440 case EHOSTUNREACH: 1441 case ENETDOWN: 1442 case EHOSTDOWN: 1443 default: 1444 type = ICMP_UNREACH; 1445 code = ICMP_UNREACH_HOST; 1446 break; 1447 1448 case EMSGSIZE: 1449 type = ICMP_UNREACH; 1450 code = ICMP_UNREACH_NEEDFRAG; 1451 1452 if ((rt = rtcache_validate(ro)) != NULL) 1453 destmtu = rt->rt_ifp->if_mtu; 1454#ifdef IPSEC 1455 if (ipsec_used) 1456 (void)ipsec4_forward(mcopy, &destmtu); 1457#endif 1458 IP_STATINC(IP_STAT_CANTFRAG); 1459 break; 1460 1461 case ENOBUFS: 1462 /* 1463 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812, 1464 * Requirements for IP Version 4 Routers. Source quench can 1465 * big problem under DoS attacks or if the underlying 1466 * interface is rate-limited. 1467 */ 1468 if (mcopy) 1469 m_freem(mcopy); 1470 percpu_putref(ipforward_rt_percpu); 1471 SOFTNET_UNLOCK(); 1472 return; 1473 } 1474 icmp_error(mcopy, type, code, dest, destmtu); 1475 percpu_putref(ipforward_rt_percpu); 1476 SOFTNET_UNLOCK(); 1477} 1478 1479void 1480ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1481 struct mbuf *m) 1482{ 1483 struct socket *so = inp->inp_socket; 1484 ifnet_t *ifp; 1485 int inpflags = inp->inp_flags; 1486 struct psref psref; 1487 1488 ifp = m_get_rcvif_psref(m, &psref); 1489 if (__predict_false(ifp == NULL)) 1490 return; /* XXX should report error? */ 1491 1492 if (so->so_options & SO_TIMESTAMP 1493#ifdef SO_OTIMESTAMP 1494 || so->so_options & SO_OTIMESTAMP 1495#endif 1496 ) { 1497 struct timeval tv; 1498 1499 microtime(&tv); 1500#ifdef SO_OTIMESTAMP 1501 if (so->so_options & SO_OTIMESTAMP) { 1502 struct timeval50 tv50; 1503 timeval_to_timeval50(&tv, &tv50); 1504 *mp = sbcreatecontrol((void *) &tv50, sizeof(tv50), 1505 SCM_OTIMESTAMP, SOL_SOCKET); 1506 } else 1507#endif 1508 *mp = sbcreatecontrol((void *) &tv, sizeof(tv), 1509 SCM_TIMESTAMP, SOL_SOCKET); 1510 if (*mp) 1511 mp = &(*mp)->m_next; 1512 } 1513 if (inpflags & INP_RECVDSTADDR) { 1514 *mp = sbcreatecontrol((void *) &ip->ip_dst, 1515 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1516 if (*mp) 1517 mp = &(*mp)->m_next; 1518 } 1519 if (inpflags & INP_RECVPKTINFO) { 1520 struct in_pktinfo ipi; 1521 ipi.ipi_addr = ip->ip_src; 1522 ipi.ipi_ifindex = ifp->if_index; 1523 *mp = sbcreatecontrol((void *) &ipi, 1524 sizeof(ipi), IP_RECVPKTINFO, IPPROTO_IP); 1525 if (*mp) 1526 mp = &(*mp)->m_next; 1527 } 1528 if (inpflags & INP_PKTINFO) { 1529 struct in_pktinfo ipi; 1530 ipi.ipi_addr = ip->ip_dst; 1531 ipi.ipi_ifindex = ifp->if_index; 1532 *mp = sbcreatecontrol((void *) &ipi, 1533 sizeof(ipi), IP_PKTINFO, IPPROTO_IP); 1534 if (*mp) 1535 mp = &(*mp)->m_next; 1536 } 1537 if (inpflags & INP_RECVIF) { 1538 struct sockaddr_dl sdl; 1539 1540 sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0, 1541 NULL, 0); 1542 *mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP); 1543 if (*mp) 1544 mp = &(*mp)->m_next; 1545 } 1546 if (inpflags & INP_RECVTTL) { 1547 *mp = sbcreatecontrol((void *) &ip->ip_ttl, 1548 sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP); 1549 if (*mp) 1550 mp = &(*mp)->m_next; 1551 } 1552 m_put_rcvif_psref(ifp, &psref); 1553} 1554 1555/* 1556 * sysctl helper routine for net.inet.ip.forwsrcrt. 1557 */ 1558static int 1559sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS) 1560{ 1561 int error, tmp; 1562 struct sysctlnode node; 1563 1564 node = *rnode; 1565 tmp = ip_forwsrcrt; 1566 node.sysctl_data = &tmp; 1567 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1568 if (error || newp == NULL) 1569 return (error); 1570 1571 error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT, 1572 0, NULL, NULL, NULL); 1573 if (error) 1574 return (error); 1575 1576 ip_forwsrcrt = tmp; 1577 1578 return (0); 1579} 1580 1581/* 1582 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the 1583 * range of the new value and tweaks timers if it changes. 1584 */ 1585static int 1586sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS) 1587{ 1588 int error, tmp; 1589 struct sysctlnode node; 1590 1591 node = *rnode; 1592 tmp = ip_mtudisc_timeout; 1593 node.sysctl_data = &tmp; 1594 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1595 if (error || newp == NULL) 1596 return (error); 1597 if (tmp < 0) 1598 return (EINVAL); 1599 1600 mutex_enter(softnet_lock); 1601 1602 ip_mtudisc_timeout = tmp; 1603 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout); 1604 1605 mutex_exit(softnet_lock); 1606 1607 return (0); 1608} 1609 1610static int 1611sysctl_net_inet_ip_stats(SYSCTLFN_ARGS) 1612{ 1613 1614 return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS)); 1615} 1616 1617static void 1618sysctl_net_inet_ip_setup(struct sysctllog **clog) 1619{ 1620 sysctl_createv(clog, 0, NULL, NULL, 1621 CTLFLAG_PERMANENT, 1622 CTLTYPE_NODE, "inet", 1623 SYSCTL_DESCR("PF_INET related settings"), 1624 NULL, 0, NULL, 0, 1625 CTL_NET, PF_INET, CTL_EOL); 1626 sysctl_createv(clog, 0, NULL, NULL, 1627 CTLFLAG_PERMANENT, 1628 CTLTYPE_NODE, "ip", 1629 SYSCTL_DESCR("IPv4 related settings"), 1630 NULL, 0, NULL, 0, 1631 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL); 1632 1633 sysctl_createv(clog, 0, NULL, NULL, 1634 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1635 CTLTYPE_INT, "forwarding", 1636 SYSCTL_DESCR("Enable forwarding of INET datagrams"), 1637 NULL, 0, &ipforwarding, 0, 1638 CTL_NET, PF_INET, IPPROTO_IP, 1639 IPCTL_FORWARDING, CTL_EOL); 1640 sysctl_createv(clog, 0, NULL, NULL, 1641 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1642 CTLTYPE_INT, "redirect", 1643 SYSCTL_DESCR("Enable sending of ICMP redirect messages"), 1644 NULL, 0, &ipsendredirects, 0, 1645 CTL_NET, PF_INET, IPPROTO_IP, 1646 IPCTL_SENDREDIRECTS, CTL_EOL); 1647 sysctl_createv(clog, 0, NULL, NULL, 1648 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1649 CTLTYPE_INT, "ttl", 1650 SYSCTL_DESCR("Default TTL for an INET datagram"), 1651 NULL, 0, &ip_defttl, 0, 1652 CTL_NET, PF_INET, IPPROTO_IP, 1653 IPCTL_DEFTTL, CTL_EOL); 1654#ifdef IPCTL_DEFMTU 1655 sysctl_createv(clog, 0, NULL, NULL, 1656 CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */, 1657 CTLTYPE_INT, "mtu", 1658 SYSCTL_DESCR("Default MTA for an INET route"), 1659 NULL, 0, &ip_mtu, 0, 1660 CTL_NET, PF_INET, IPPROTO_IP, 1661 IPCTL_DEFMTU, CTL_EOL); 1662#endif /* IPCTL_DEFMTU */ 1663 sysctl_createv(clog, 0, NULL, NULL, 1664 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1665 CTLTYPE_INT, "forwsrcrt", 1666 SYSCTL_DESCR("Enable forwarding of source-routed " 1667 "datagrams"), 1668 sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0, 1669 CTL_NET, PF_INET, IPPROTO_IP, 1670 IPCTL_FORWSRCRT, CTL_EOL); 1671 sysctl_createv(clog, 0, NULL, NULL, 1672 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1673 CTLTYPE_INT, "directed-broadcast", 1674 SYSCTL_DESCR("Enable forwarding of broadcast datagrams"), 1675 NULL, 0, &ip_directedbcast, 0, 1676 CTL_NET, PF_INET, IPPROTO_IP, 1677 IPCTL_DIRECTEDBCAST, CTL_EOL); 1678 sysctl_createv(clog, 0, NULL, NULL, 1679 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1680 CTLTYPE_INT, "allowsrcrt", 1681 SYSCTL_DESCR("Accept source-routed datagrams"), 1682 NULL, 0, &ip_allowsrcrt, 0, 1683 CTL_NET, PF_INET, IPPROTO_IP, 1684 IPCTL_ALLOWSRCRT, CTL_EOL); 1685 1686 sysctl_createv(clog, 0, NULL, NULL, 1687 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1688 CTLTYPE_INT, "mtudisc", 1689 SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"), 1690 NULL, 0, &ip_mtudisc, 0, 1691 CTL_NET, PF_INET, IPPROTO_IP, 1692 IPCTL_MTUDISC, CTL_EOL); 1693 sysctl_createv(clog, 0, NULL, NULL, 1694 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1695 CTLTYPE_INT, "anonportmin", 1696 SYSCTL_DESCR("Lowest ephemeral port number to assign"), 1697 sysctl_net_inet_ip_ports, 0, &anonportmin, 0, 1698 CTL_NET, PF_INET, IPPROTO_IP, 1699 IPCTL_ANONPORTMIN, CTL_EOL); 1700 sysctl_createv(clog, 0, NULL, NULL, 1701 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1702 CTLTYPE_INT, "anonportmax", 1703 SYSCTL_DESCR("Highest ephemeral port number to assign"), 1704 sysctl_net_inet_ip_ports, 0, &anonportmax, 0, 1705 CTL_NET, PF_INET, IPPROTO_IP, 1706 IPCTL_ANONPORTMAX, CTL_EOL); 1707 sysctl_createv(clog, 0, NULL, NULL, 1708 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1709 CTLTYPE_INT, "mtudisctimeout", 1710 SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"), 1711 sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0, 1712 CTL_NET, PF_INET, IPPROTO_IP, 1713 IPCTL_MTUDISCTIMEOUT, CTL_EOL); 1714#ifndef IPNOPRIVPORTS 1715 sysctl_createv(clog, 0, NULL, NULL, 1716 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1717 CTLTYPE_INT, "lowportmin", 1718 SYSCTL_DESCR("Lowest privileged ephemeral port number " 1719 "to assign"), 1720 sysctl_net_inet_ip_ports, 0, &lowportmin, 0, 1721 CTL_NET, PF_INET, IPPROTO_IP, 1722 IPCTL_LOWPORTMIN, CTL_EOL); 1723 sysctl_createv(clog, 0, NULL, NULL, 1724 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1725 CTLTYPE_INT, "lowportmax", 1726 SYSCTL_DESCR("Highest privileged ephemeral port number " 1727 "to assign"), 1728 sysctl_net_inet_ip_ports, 0, &lowportmax, 0, 1729 CTL_NET, PF_INET, IPPROTO_IP, 1730 IPCTL_LOWPORTMAX, CTL_EOL); 1731#endif /* IPNOPRIVPORTS */ 1732#if NGRE > 0 1733 sysctl_createv(clog, 0, NULL, NULL, 1734 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1735 CTLTYPE_INT, "grettl", 1736 SYSCTL_DESCR("Default TTL for a gre tunnel datagram"), 1737 NULL, 0, &ip_gre_ttl, 0, 1738 CTL_NET, PF_INET, IPPROTO_IP, 1739 IPCTL_GRE_TTL, CTL_EOL); 1740#endif /* NGRE */ 1741 sysctl_createv(clog, 0, NULL, NULL, 1742 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1743 CTLTYPE_INT, "checkinterface", 1744 SYSCTL_DESCR("Enable receive side of Strong ES model " 1745 "from RFC1122"), 1746 NULL, 0, &ip_checkinterface, 0, 1747 CTL_NET, PF_INET, IPPROTO_IP, 1748 IPCTL_CHECKINTERFACE, CTL_EOL); 1749 sysctl_createv(clog, 0, NULL, NULL, 1750 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1751 CTLTYPE_INT, "random_id", 1752 SYSCTL_DESCR("Assign random ip_id values"), 1753 NULL, 0, &ip_do_randomid, 0, 1754 CTL_NET, PF_INET, IPPROTO_IP, 1755 IPCTL_RANDOMID, CTL_EOL); 1756 sysctl_createv(clog, 0, NULL, NULL, 1757 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1758 CTLTYPE_INT, "do_loopback_cksum", 1759 SYSCTL_DESCR("Perform IP checksum on loopback"), 1760 NULL, 0, &ip_do_loopback_cksum, 0, 1761 CTL_NET, PF_INET, IPPROTO_IP, 1762 IPCTL_LOOPBACKCKSUM, CTL_EOL); 1763 sysctl_createv(clog, 0, NULL, NULL, 1764 CTLFLAG_PERMANENT, 1765 CTLTYPE_STRUCT, "stats", 1766 SYSCTL_DESCR("IP statistics"), 1767 sysctl_net_inet_ip_stats, 0, NULL, 0, 1768 CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS, 1769 CTL_EOL); 1770#if NARP 1771 sysctl_createv(clog, 0, NULL, NULL, 1772 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1773 CTLTYPE_INT, "dad_count", 1774 SYSCTL_DESCR("Number of Duplicate Address Detection " 1775 "probes to send"), 1776 NULL, 0, &ip_dad_count, 0, 1777 CTL_NET, PF_INET, IPPROTO_IP, 1778 IPCTL_DAD_COUNT, CTL_EOL); 1779#endif 1780 1781 /* anonportalgo RFC6056 subtree */ 1782 const struct sysctlnode *portalgo_node; 1783 sysctl_createv(clog, 0, NULL, &portalgo_node, 1784 CTLFLAG_PERMANENT, 1785 CTLTYPE_NODE, "anonportalgo", 1786 SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"), 1787 NULL, 0, NULL, 0, 1788 CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL); 1789 sysctl_createv(clog, 0, &portalgo_node, NULL, 1790 CTLFLAG_PERMANENT, 1791 CTLTYPE_STRING, "available", 1792 SYSCTL_DESCR("available algorithms"), 1793 sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN, 1794 CTL_CREATE, CTL_EOL); 1795 sysctl_createv(clog, 0, &portalgo_node, NULL, 1796 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1797 CTLTYPE_STRING, "selected", 1798 SYSCTL_DESCR("selected algorithm"), 1799 sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN, 1800 CTL_CREATE, CTL_EOL); 1801 sysctl_createv(clog, 0, &portalgo_node, NULL, 1802 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1803 CTLTYPE_STRUCT, "reserve", 1804 SYSCTL_DESCR("bitmap of reserved ports"), 1805 sysctl_portalgo_reserve4, 0, NULL, 0, 1806 CTL_CREATE, CTL_EOL); 1807} 1808 1809void 1810ip_statinc(u_int stat) 1811{ 1812 1813 KASSERT(stat < IP_NSTATS); 1814 IP_STATINC(stat); 1815} 1816