ip_input.c revision 1.341
1/* $NetBSD: ip_input.c,v 1.341 2016/09/07 15:41:44 roy 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 1.341 2016/09/07 15:41:44 roy 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 goto out; 622 } 623 ip = mtod(m, struct ip *); 624 hlen = ip->ip_hl << 2; 625 626 /* 627 * XXX The setting of "srcrt" here is to prevent ip_forward() 628 * from generating ICMP redirects for packets that have 629 * been redirected by a hook back out on to the same LAN that 630 * they came from and is not an indication that the packet 631 * is being inffluenced by source routing options. This 632 * allows things like 633 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp" 634 * where tlp0 is both on the 1.1.1.0/24 network and is the 635 * default route for hosts on 1.1.1.0/24. Of course this 636 * also requires a "map tlp0 ..." to complete the story. 637 * One might argue whether or not this kind of network config. 638 * should be supported in this manner... 639 */ 640 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 641 } 642 643#ifdef ALTQ 644 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 645 if (altq_input) { 646 SOFTNET_LOCK(); 647 if ((*altq_input)(m, AF_INET) == 0) { 648 /* Packet dropped by traffic conditioner. */ 649 SOFTNET_UNLOCK(); 650 goto out; 651 } 652 SOFTNET_UNLOCK(); 653 } 654#endif 655 656 /* 657 * Process options and, if not destined for us, 658 * ship it on. ip_dooptions returns 1 when an 659 * error was detected (causing an icmp message 660 * to be sent and the original packet to be freed). 661 */ 662 ip_nhops = 0; /* for source routed packets */ 663 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 664 goto out; 665 666 /* 667 * Check our list of addresses, to see if the packet is for us. 668 * 669 * Traditional 4.4BSD did not consult IFF_UP at all. 670 * The behavior here is to treat addresses on !IFF_UP interface 671 * or IN_IFF_NOTREADY addresses as not mine. 672 */ 673 downmatch = 0; 674 s = pserialize_read_enter(); 675 ia = ip_match_our_address(ifp, ip, &downmatch); 676 if (ia != NULL) { 677 pserialize_read_exit(s); 678 goto ours; 679 } 680 681 if (ifp->if_flags & IFF_BROADCAST) { 682 ia = ip_match_our_address_broadcast(ifp, ip); 683 if (ia != NULL) { 684 pserialize_read_exit(s); 685 goto ours; 686 } 687 } 688 pserialize_read_exit(s); 689 690 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 691#ifdef MROUTING 692 extern struct socket *ip_mrouter; 693 694 if (ip_mrouter) { 695 /* 696 * If we are acting as a multicast router, all 697 * incoming multicast packets are passed to the 698 * kernel-level multicast forwarding function. 699 * The packet is returned (relatively) intact; if 700 * ip_mforward() returns a non-zero value, the packet 701 * must be discarded, else it may be accepted below. 702 * 703 * (The IP ident field is put in the same byte order 704 * as expected when ip_mforward() is called from 705 * ip_output().) 706 */ 707 SOFTNET_LOCK(); 708 if (ip_mforward(m, ifp) != 0) { 709 SOFTNET_UNLOCK(); 710 IP_STATINC(IP_STAT_CANTFORWARD); 711 goto out; 712 } 713 SOFTNET_UNLOCK(); 714 715 /* 716 * The process-level routing demon needs to receive 717 * all multicast IGMP packets, whether or not this 718 * host belongs to their destination groups. 719 */ 720 if (ip->ip_p == IPPROTO_IGMP) { 721 goto ours; 722 } 723 IP_STATINC(IP_STAT_CANTFORWARD); 724 } 725#endif 726 /* 727 * See if we belong to the destination multicast group on the 728 * arrival interface. 729 */ 730 if (!in_multi_group(ip->ip_dst, ifp, 0)) { 731 IP_STATINC(IP_STAT_CANTFORWARD); 732 goto out; 733 } 734 goto ours; 735 } 736 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 737 in_nullhost(ip->ip_dst)) 738 goto ours; 739 740 /* 741 * Not for us; forward if possible and desirable. 742 */ 743 if (ipforwarding == 0) { 744 m_put_rcvif_psref(ifp, &psref); 745 IP_STATINC(IP_STAT_CANTFORWARD); 746 m_freem(m); 747 } else { 748 /* 749 * If ip_dst matched any of my address on !IFF_UP interface, 750 * and there's no IFF_UP interface that matches ip_dst, 751 * send icmp unreach. Forwarding it will result in in-kernel 752 * forwarding loop till TTL goes to 0. 753 */ 754 if (downmatch) { 755 m_put_rcvif_psref(ifp, &psref); 756 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 757 IP_STATINC(IP_STAT_CANTFORWARD); 758 return; 759 } 760#ifdef IPSEC 761 /* Perform IPsec, if any. */ 762 if (ipsec_used) { 763 SOFTNET_LOCK(); 764 if (ipsec4_input(m, IP_FORWARDING | 765 (ip_directedbcast ? IP_ALLOWBROADCAST : 0)) != 0) { 766 SOFTNET_UNLOCK(); 767 goto out; 768 } 769 SOFTNET_UNLOCK(); 770 } 771#endif 772 ip_forward(m, srcrt, ifp); 773 m_put_rcvif_psref(ifp, &psref); 774 } 775 return; 776 777ours: 778 m_put_rcvif_psref(ifp, &psref); 779 ifp = NULL; 780 781 /* 782 * If offset or IP_MF are set, must reassemble. 783 */ 784 if (ip->ip_off & ~htons(IP_DF|IP_RF)) { 785 /* 786 * Pass to IP reassembly mechanism. 787 */ 788 if (ip_reass_packet(&m, ip) != 0) { 789 /* Failed; invalid fragment(s) or packet. */ 790 goto out; 791 } 792 if (m == NULL) { 793 /* More fragments should come; silently return. */ 794 goto out; 795 } 796 /* 797 * Reassembly is done, we have the final packet. 798 * Updated cached data in local variable(s). 799 */ 800 ip = mtod(m, struct ip *); 801 hlen = ip->ip_hl << 2; 802 } 803 804#ifdef IPSEC 805 /* 806 * Enforce IPsec policy checking if we are seeing last header. 807 * Note that we do not visit this with protocols with PCB layer 808 * code - like UDP/TCP/raw IP. 809 */ 810 if (ipsec_used && 811 (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 812 SOFTNET_LOCK(); 813 if (ipsec4_input(m, 0) != 0) { 814 SOFTNET_UNLOCK(); 815 goto out; 816 } 817 SOFTNET_UNLOCK(); 818 } 819#endif 820 821 /* 822 * Switch out to protocol's input routine. 823 */ 824#if IFA_STATS 825 if (ia && ip) { 826 struct in_ifaddr *_ia; 827 /* 828 * Keep a reference from ip_match_our_address with psref 829 * is expensive, so explore ia here again. 830 */ 831 s = pserialize_read_enter(); 832 _ia = in_get_ia(ip->ip_dst.s_addr); 833 _ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len); 834 pserialize_read_exit(s); 835 } 836#endif 837 IP_STATINC(IP_STAT_DELIVERED); 838 839 const int off = hlen, nh = ip->ip_p; 840 841 SOFTNET_LOCK(); 842 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 843 SOFTNET_UNLOCK(); 844 return; 845 846out: 847 m_put_rcvif_psref(ifp, &psref); 848 if (m != NULL) 849 m_freem(m); 850} 851 852/* 853 * IP timer processing. 854 */ 855void 856ip_slowtimo(void) 857{ 858 859 mutex_enter(softnet_lock); 860 KERNEL_LOCK(1, NULL); 861 862 ip_reass_slowtimo(); 863 864 KERNEL_UNLOCK_ONE(NULL); 865 mutex_exit(softnet_lock); 866} 867 868/* 869 * IP drain processing. 870 */ 871void 872ip_drain(void) 873{ 874 875 KERNEL_LOCK(1, NULL); 876 ip_reass_drain(); 877 KERNEL_UNLOCK_ONE(NULL); 878} 879 880/* 881 * ip_dooptions: perform option processing on a datagram, possibly discarding 882 * it if bad options are encountered, or forwarding it if source-routed. 883 * 884 * => Returns true if packet has been forwarded/freed. 885 * => Returns false if the packet should be processed further. 886 */ 887static bool 888ip_dooptions(struct mbuf *m) 889{ 890 struct ip *ip = mtod(m, struct ip *); 891 u_char *cp, *cp0; 892 struct ip_timestamp *ipt; 893 struct in_ifaddr *ia; 894 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 895 struct in_addr dst; 896 n_time ntime; 897 struct ifaddr *ifa; 898 int s; 899 900 dst = ip->ip_dst; 901 cp = (u_char *)(ip + 1); 902 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 903 for (; cnt > 0; cnt -= optlen, cp += optlen) { 904 opt = cp[IPOPT_OPTVAL]; 905 if (opt == IPOPT_EOL) 906 break; 907 if (opt == IPOPT_NOP) 908 optlen = 1; 909 else { 910 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 911 code = &cp[IPOPT_OLEN] - (u_char *)ip; 912 goto bad; 913 } 914 optlen = cp[IPOPT_OLEN]; 915 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 916 code = &cp[IPOPT_OLEN] - (u_char *)ip; 917 goto bad; 918 } 919 } 920 switch (opt) { 921 922 default: 923 break; 924 925 /* 926 * Source routing with record. 927 * Find interface with current destination address. 928 * If none on this machine then drop if strictly routed, 929 * or do nothing if loosely routed. 930 * Record interface address and bring up next address 931 * component. If strictly routed make sure next 932 * address is on directly accessible net. 933 */ 934 case IPOPT_LSRR: 935 case IPOPT_SSRR: 936 if (ip_allowsrcrt == 0) { 937 type = ICMP_UNREACH; 938 code = ICMP_UNREACH_NET_PROHIB; 939 goto bad; 940 } 941 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 942 code = &cp[IPOPT_OLEN] - (u_char *)ip; 943 goto bad; 944 } 945 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 946 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 947 goto bad; 948 } 949 ipaddr.sin_addr = ip->ip_dst; 950 951 s = pserialize_read_enter(); 952 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 953 if (ifa == NULL) { 954 pserialize_read_exit(s); 955 if (opt == IPOPT_SSRR) { 956 type = ICMP_UNREACH; 957 code = ICMP_UNREACH_SRCFAIL; 958 goto bad; 959 } 960 /* 961 * Loose routing, and not at next destination 962 * yet; nothing to do except forward. 963 */ 964 break; 965 } 966 pserialize_read_exit(s); 967 968 off--; /* 0 origin */ 969 if ((off + sizeof(struct in_addr)) > optlen) { 970 /* 971 * End of source route. Should be for us. 972 */ 973 save_rte(cp, ip->ip_src); 974 break; 975 } 976 /* 977 * locate outgoing interface 978 */ 979 memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off), 980 sizeof(ipaddr.sin_addr)); 981 s = pserialize_read_enter(); 982 if (opt == IPOPT_SSRR) { 983 ifa = ifa_ifwithladdr(sintosa(&ipaddr)); 984 if (ifa != NULL) 985 ia = ifatoia(ifa); 986 else 987 ia = NULL; 988 } else { 989 ia = ip_rtaddr(ipaddr.sin_addr); 990 } 991 if (ia == NULL) { 992 type = ICMP_UNREACH; 993 code = ICMP_UNREACH_SRCFAIL; 994 pserialize_read_exit(s); 995 goto bad; 996 } 997 ip->ip_dst = ipaddr.sin_addr; 998 bcopy((void *)&ia->ia_addr.sin_addr, 999 (void *)(cp + off), sizeof(struct in_addr)); 1000 pserialize_read_exit(s); 1001 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1002 /* 1003 * Let ip_intr's mcast routing check handle mcast pkts 1004 */ 1005 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1006 break; 1007 1008 case IPOPT_RR: 1009 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1010 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1011 goto bad; 1012 } 1013 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1014 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1015 goto bad; 1016 } 1017 /* 1018 * If no space remains, ignore. 1019 */ 1020 off--; /* 0 origin */ 1021 if ((off + sizeof(struct in_addr)) > optlen) 1022 break; 1023 memcpy((void *)&ipaddr.sin_addr, (void *)(&ip->ip_dst), 1024 sizeof(ipaddr.sin_addr)); 1025 /* 1026 * locate outgoing interface; if we're the destination, 1027 * use the incoming interface (should be same). 1028 */ 1029 s = pserialize_read_enter(); 1030 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 1031 if (ifa == NULL) { 1032 ia = ip_rtaddr(ipaddr.sin_addr); 1033 if (ia == NULL) { 1034 pserialize_read_exit(s); 1035 type = ICMP_UNREACH; 1036 code = ICMP_UNREACH_HOST; 1037 goto bad; 1038 } 1039 } else { 1040 ia = ifatoia(ifa); 1041 } 1042 bcopy((void *)&ia->ia_addr.sin_addr, 1043 (void *)(cp + off), sizeof(struct in_addr)); 1044 pserialize_read_exit(s); 1045 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1046 break; 1047 1048 case IPOPT_TS: 1049 code = cp - (u_char *)ip; 1050 ipt = (struct ip_timestamp *)cp; 1051 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1052 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1053 goto bad; 1054 } 1055 if (ipt->ipt_ptr < 5) { 1056 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1057 goto bad; 1058 } 1059 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) { 1060 if (++ipt->ipt_oflw == 0) { 1061 code = (u_char *)&ipt->ipt_ptr - 1062 (u_char *)ip; 1063 goto bad; 1064 } 1065 break; 1066 } 1067 cp0 = (cp + ipt->ipt_ptr - 1); 1068 switch (ipt->ipt_flg) { 1069 1070 case IPOPT_TS_TSONLY: 1071 break; 1072 1073 case IPOPT_TS_TSANDADDR: { 1074 struct ifnet *rcvif; 1075 int _s, _ss; 1076 1077 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1078 sizeof(struct in_addr) > ipt->ipt_len) { 1079 code = (u_char *)&ipt->ipt_ptr - 1080 (u_char *)ip; 1081 goto bad; 1082 } 1083 ipaddr.sin_addr = dst; 1084 _ss = pserialize_read_enter(); 1085 rcvif = m_get_rcvif(m, &_s); 1086 ifa = ifaof_ifpforaddr(sintosa(&ipaddr), rcvif); 1087 m_put_rcvif(rcvif, &_s); 1088 if (ifa == NULL) { 1089 pserialize_read_exit(_ss); 1090 break; 1091 } 1092 ia = ifatoia(ifa); 1093 bcopy(&ia->ia_addr.sin_addr, 1094 cp0, sizeof(struct in_addr)); 1095 pserialize_read_exit(_ss); 1096 ipt->ipt_ptr += sizeof(struct in_addr); 1097 break; 1098 } 1099 1100 case IPOPT_TS_PRESPEC: 1101 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1102 sizeof(struct in_addr) > ipt->ipt_len) { 1103 code = (u_char *)&ipt->ipt_ptr - 1104 (u_char *)ip; 1105 goto bad; 1106 } 1107 memcpy(&ipaddr.sin_addr, cp0, 1108 sizeof(struct in_addr)); 1109 s = pserialize_read_enter(); 1110 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 1111 if (ifa == NULL) { 1112 pserialize_read_exit(s); 1113 continue; 1114 } 1115 pserialize_read_exit(s); 1116 ipt->ipt_ptr += sizeof(struct in_addr); 1117 break; 1118 1119 default: 1120 /* XXX can't take &ipt->ipt_flg */ 1121 code = (u_char *)&ipt->ipt_ptr - 1122 (u_char *)ip + 1; 1123 goto bad; 1124 } 1125 ntime = iptime(); 1126 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1127 memmove((char *)cp + ipt->ipt_ptr - 1, cp0, 1128 sizeof(n_time)); 1129 ipt->ipt_ptr += sizeof(n_time); 1130 } 1131 } 1132 if (forward) { 1133 struct ifnet *rcvif; 1134 struct psref _psref; 1135 1136 if (ip_forwsrcrt == 0) { 1137 type = ICMP_UNREACH; 1138 code = ICMP_UNREACH_SRCFAIL; 1139 goto bad; 1140 } 1141 1142 rcvif = m_get_rcvif_psref(m, &_psref); 1143 if (__predict_false(rcvif == NULL)) { 1144 type = ICMP_UNREACH; 1145 code = ICMP_UNREACH_HOST; 1146 goto bad; 1147 } 1148 ip_forward(m, 1, rcvif); 1149 m_put_rcvif_psref(rcvif, &_psref); 1150 return true; 1151 } 1152 return false; 1153bad: 1154 icmp_error(m, type, code, 0, 0); 1155 IP_STATINC(IP_STAT_BADOPTIONS); 1156 return true; 1157} 1158 1159/* 1160 * ip_rtaddr: given address of next destination (final or next hop), 1161 * return internet address info of interface to be used to get there. 1162 */ 1163static struct in_ifaddr * 1164ip_rtaddr(struct in_addr dst) 1165{ 1166 struct rtentry *rt; 1167 union { 1168 struct sockaddr dst; 1169 struct sockaddr_in dst4; 1170 } u; 1171 struct route *ro; 1172 1173 sockaddr_in_init(&u.dst4, &dst, 0); 1174 1175 SOFTNET_LOCK(); 1176 ro = percpu_getref(ipforward_rt_percpu); 1177 rt = rtcache_lookup(ro, &u.dst); 1178 percpu_putref(ipforward_rt_percpu); 1179 SOFTNET_UNLOCK(); 1180 if (rt == NULL) 1181 return NULL; 1182 1183 return ifatoia(rt->rt_ifa); 1184} 1185 1186/* 1187 * save_rte: save incoming source route for use in replies, to be picked 1188 * up later by ip_srcroute if the receiver is interested. 1189 */ 1190static void 1191save_rte(u_char *option, struct in_addr dst) 1192{ 1193 unsigned olen; 1194 1195 olen = option[IPOPT_OLEN]; 1196 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1197 return; 1198 memcpy((void *)ip_srcrt.srcopt, (void *)option, olen); 1199 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1200 ip_srcrt.dst = dst; 1201} 1202 1203/* 1204 * Retrieve incoming source route for use in replies, 1205 * in the same form used by setsockopt. 1206 * The first hop is placed before the options, will be removed later. 1207 */ 1208struct mbuf * 1209ip_srcroute(void) 1210{ 1211 struct in_addr *p, *q; 1212 struct mbuf *m; 1213 1214 if (ip_nhops == 0) 1215 return NULL; 1216 m = m_get(M_DONTWAIT, MT_SOOPTS); 1217 if (m == 0) 1218 return NULL; 1219 1220 MCLAIM(m, &inetdomain.dom_mowner); 1221#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1222 1223 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1224 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1225 OPTSIZ; 1226 1227 /* 1228 * First save first hop for return route 1229 */ 1230 p = &ip_srcrt.route[ip_nhops - 1]; 1231 *(mtod(m, struct in_addr *)) = *p--; 1232 1233 /* 1234 * Copy option fields and padding (nop) to mbuf. 1235 */ 1236 ip_srcrt.nop = IPOPT_NOP; 1237 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1238 memmove(mtod(m, char *) + sizeof(struct in_addr), &ip_srcrt.nop, 1239 OPTSIZ); 1240 q = (struct in_addr *)(mtod(m, char *) + 1241 sizeof(struct in_addr) + OPTSIZ); 1242#undef OPTSIZ 1243 /* 1244 * Record return path as an IP source route, 1245 * reversing the path (pointers are now aligned). 1246 */ 1247 while (p >= ip_srcrt.route) { 1248 *q++ = *p--; 1249 } 1250 /* 1251 * Last hop goes to final destination. 1252 */ 1253 *q = ip_srcrt.dst; 1254 return (m); 1255} 1256 1257const int inetctlerrmap[PRC_NCMDS] = { 1258 [PRC_MSGSIZE] = EMSGSIZE, 1259 [PRC_HOSTDEAD] = EHOSTDOWN, 1260 [PRC_HOSTUNREACH] = EHOSTUNREACH, 1261 [PRC_UNREACH_NET] = EHOSTUNREACH, 1262 [PRC_UNREACH_HOST] = EHOSTUNREACH, 1263 [PRC_UNREACH_PROTOCOL] = ECONNREFUSED, 1264 [PRC_UNREACH_PORT] = ECONNREFUSED, 1265 [PRC_UNREACH_SRCFAIL] = EHOSTUNREACH, 1266 [PRC_PARAMPROB] = ENOPROTOOPT, 1267}; 1268 1269void 1270ip_fasttimo(void) 1271{ 1272 if (ip_drainwanted) { 1273 ip_drain(); 1274 ip_drainwanted = 0; 1275 } 1276} 1277 1278void 1279ip_drainstub(void) 1280{ 1281 ip_drainwanted = 1; 1282} 1283 1284/* 1285 * Forward a packet. If some error occurs return the sender 1286 * an icmp packet. Note we can't always generate a meaningful 1287 * icmp message because icmp doesn't have a large enough repertoire 1288 * of codes and types. 1289 * 1290 * If not forwarding, just drop the packet. This could be confusing 1291 * if ipforwarding was zero but some routing protocol was advancing 1292 * us as a gateway to somewhere. However, we must let the routing 1293 * protocol deal with that. 1294 * 1295 * The srcrt parameter indicates whether the packet is being forwarded 1296 * via a source route. 1297 */ 1298static void 1299ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif) 1300{ 1301 struct ip *ip = mtod(m, struct ip *); 1302 struct rtentry *rt; 1303 int error, type = 0, code = 0, destmtu = 0; 1304 struct mbuf *mcopy; 1305 n_long dest; 1306 union { 1307 struct sockaddr dst; 1308 struct sockaddr_in dst4; 1309 } u; 1310 uint64_t *ips; 1311 struct route *ro; 1312 1313 KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software " 1314 "interrupt handler; synchronization assumptions violated"); 1315 1316 /* 1317 * We are now in the output path. 1318 */ 1319 MCLAIM(m, &ip_tx_mowner); 1320 1321 /* 1322 * Clear any in-bound checksum flags for this packet. 1323 */ 1324 m->m_pkthdr.csum_flags = 0; 1325 1326 dest = 0; 1327 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1328 IP_STATINC(IP_STAT_CANTFORWARD); 1329 m_freem(m); 1330 return; 1331 } 1332 1333 SOFTNET_LOCK(); 1334 1335 if (ip->ip_ttl <= IPTTLDEC) { 1336 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1337 SOFTNET_UNLOCK(); 1338 return; 1339 } 1340 1341 sockaddr_in_init(&u.dst4, &ip->ip_dst, 0); 1342 1343 ro = percpu_getref(ipforward_rt_percpu); 1344 if ((rt = rtcache_lookup(ro, &u.dst)) == NULL) { 1345 percpu_putref(ipforward_rt_percpu); 1346 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0); 1347 SOFTNET_UNLOCK(); 1348 return; 1349 } 1350 1351 /* 1352 * Save at most 68 bytes of the packet in case 1353 * we need to generate an ICMP message to the src. 1354 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1355 */ 1356 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1357 if (mcopy) 1358 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1359 1360 ip->ip_ttl -= IPTTLDEC; 1361 1362 /* 1363 * If forwarding packet using same interface that it came in on, 1364 * perhaps should send a redirect to sender to shortcut a hop. 1365 * Only send redirect if source is sending directly to us, 1366 * and if packet was not source routed (or has any options). 1367 * Also, don't send redirect if forwarding using a default route 1368 * or a route modified by a redirect. 1369 */ 1370 if (rt->rt_ifp == rcvif && 1371 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1372 !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) && 1373 ipsendredirects && !srcrt) { 1374 if (rt->rt_ifa && 1375 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1376 ifatoia(rt->rt_ifa)->ia_subnet) { 1377 if (rt->rt_flags & RTF_GATEWAY) 1378 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1379 else 1380 dest = ip->ip_dst.s_addr; 1381 /* 1382 * Router requirements says to only send host 1383 * redirects. 1384 */ 1385 type = ICMP_REDIRECT; 1386 code = ICMP_REDIRECT_HOST; 1387 } 1388 } 1389 1390 error = ip_output(m, NULL, ro, 1391 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1392 NULL, NULL); 1393 1394 if (error) { 1395 IP_STATINC(IP_STAT_CANTFORWARD); 1396 goto error; 1397 } 1398 1399 ips = IP_STAT_GETREF(); 1400 ips[IP_STAT_FORWARD]++; 1401 1402 if (type) { 1403 ips[IP_STAT_REDIRECTSENT]++; 1404 IP_STAT_PUTREF(); 1405 goto redirect; 1406 } 1407 1408 IP_STAT_PUTREF(); 1409 if (mcopy) { 1410#ifdef GATEWAY 1411 if (mcopy->m_flags & M_CANFASTFWD) 1412 ipflow_create(ro, mcopy); 1413#endif 1414 m_freem(mcopy); 1415 } 1416 1417 percpu_putref(ipforward_rt_percpu); 1418 SOFTNET_UNLOCK(); 1419 return; 1420 1421redirect: 1422error: 1423 if (mcopy == NULL) { 1424 percpu_putref(ipforward_rt_percpu); 1425 SOFTNET_UNLOCK(); 1426 return; 1427 } 1428 1429 switch (error) { 1430 1431 case 0: /* forwarded, but need redirect */ 1432 /* type, code set above */ 1433 break; 1434 1435 case ENETUNREACH: /* shouldn't happen, checked above */ 1436 case EHOSTUNREACH: 1437 case ENETDOWN: 1438 case EHOSTDOWN: 1439 default: 1440 type = ICMP_UNREACH; 1441 code = ICMP_UNREACH_HOST; 1442 break; 1443 1444 case EMSGSIZE: 1445 type = ICMP_UNREACH; 1446 code = ICMP_UNREACH_NEEDFRAG; 1447 1448 if ((rt = rtcache_validate(ro)) != NULL) 1449 destmtu = rt->rt_ifp->if_mtu; 1450#ifdef IPSEC 1451 if (ipsec_used) 1452 (void)ipsec4_forward(mcopy, &destmtu); 1453#endif 1454 IP_STATINC(IP_STAT_CANTFRAG); 1455 break; 1456 1457 case ENOBUFS: 1458 /* 1459 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812, 1460 * Requirements for IP Version 4 Routers. Source quench can 1461 * big problem under DoS attacks or if the underlying 1462 * interface is rate-limited. 1463 */ 1464 if (mcopy) 1465 m_freem(mcopy); 1466 percpu_putref(ipforward_rt_percpu); 1467 SOFTNET_UNLOCK(); 1468 return; 1469 } 1470 icmp_error(mcopy, type, code, dest, destmtu); 1471 percpu_putref(ipforward_rt_percpu); 1472 SOFTNET_UNLOCK(); 1473} 1474 1475void 1476ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1477 struct mbuf *m) 1478{ 1479 struct socket *so = inp->inp_socket; 1480 ifnet_t *ifp; 1481 int inpflags = inp->inp_flags; 1482 struct psref psref; 1483 1484 ifp = m_get_rcvif_psref(m, &psref); 1485 if (__predict_false(ifp == NULL)) 1486 return; /* XXX should report error? */ 1487 1488 if (so->so_options & SO_TIMESTAMP 1489#ifdef SO_OTIMESTAMP 1490 || so->so_options & SO_OTIMESTAMP 1491#endif 1492 ) { 1493 struct timeval tv; 1494 1495 microtime(&tv); 1496#ifdef SO_OTIMESTAMP 1497 if (so->so_options & SO_OTIMESTAMP) { 1498 struct timeval50 tv50; 1499 timeval_to_timeval50(&tv, &tv50); 1500 *mp = sbcreatecontrol((void *) &tv50, sizeof(tv50), 1501 SCM_OTIMESTAMP, SOL_SOCKET); 1502 } else 1503#endif 1504 *mp = sbcreatecontrol((void *) &tv, sizeof(tv), 1505 SCM_TIMESTAMP, SOL_SOCKET); 1506 if (*mp) 1507 mp = &(*mp)->m_next; 1508 } 1509 if (inpflags & INP_RECVDSTADDR) { 1510 *mp = sbcreatecontrol((void *) &ip->ip_dst, 1511 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1512 if (*mp) 1513 mp = &(*mp)->m_next; 1514 } 1515 if (inpflags & INP_RECVPKTINFO) { 1516 struct in_pktinfo ipi; 1517 ipi.ipi_addr = ip->ip_src; 1518 ipi.ipi_ifindex = ifp->if_index; 1519 *mp = sbcreatecontrol((void *) &ipi, 1520 sizeof(ipi), IP_RECVPKTINFO, IPPROTO_IP); 1521 if (*mp) 1522 mp = &(*mp)->m_next; 1523 } 1524 if (inpflags & INP_PKTINFO) { 1525 struct in_pktinfo ipi; 1526 ipi.ipi_addr = ip->ip_dst; 1527 ipi.ipi_ifindex = ifp->if_index; 1528 *mp = sbcreatecontrol((void *) &ipi, 1529 sizeof(ipi), IP_PKTINFO, IPPROTO_IP); 1530 if (*mp) 1531 mp = &(*mp)->m_next; 1532 } 1533 if (inpflags & INP_RECVIF) { 1534 struct sockaddr_dl sdl; 1535 1536 sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0, 1537 NULL, 0); 1538 *mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP); 1539 if (*mp) 1540 mp = &(*mp)->m_next; 1541 } 1542 if (inpflags & INP_RECVTTL) { 1543 *mp = sbcreatecontrol((void *) &ip->ip_ttl, 1544 sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP); 1545 if (*mp) 1546 mp = &(*mp)->m_next; 1547 } 1548 m_put_rcvif_psref(ifp, &psref); 1549} 1550 1551/* 1552 * sysctl helper routine for net.inet.ip.forwsrcrt. 1553 */ 1554static int 1555sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS) 1556{ 1557 int error, tmp; 1558 struct sysctlnode node; 1559 1560 node = *rnode; 1561 tmp = ip_forwsrcrt; 1562 node.sysctl_data = &tmp; 1563 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1564 if (error || newp == NULL) 1565 return (error); 1566 1567 error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT, 1568 0, NULL, NULL, NULL); 1569 if (error) 1570 return (error); 1571 1572 ip_forwsrcrt = tmp; 1573 1574 return (0); 1575} 1576 1577/* 1578 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the 1579 * range of the new value and tweaks timers if it changes. 1580 */ 1581static int 1582sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS) 1583{ 1584 int error, tmp; 1585 struct sysctlnode node; 1586 1587 node = *rnode; 1588 tmp = ip_mtudisc_timeout; 1589 node.sysctl_data = &tmp; 1590 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1591 if (error || newp == NULL) 1592 return (error); 1593 if (tmp < 0) 1594 return (EINVAL); 1595 1596 mutex_enter(softnet_lock); 1597 1598 ip_mtudisc_timeout = tmp; 1599 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout); 1600 1601 mutex_exit(softnet_lock); 1602 1603 return (0); 1604} 1605 1606static int 1607sysctl_net_inet_ip_stats(SYSCTLFN_ARGS) 1608{ 1609 1610 return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS)); 1611} 1612 1613static void 1614sysctl_net_inet_ip_setup(struct sysctllog **clog) 1615{ 1616 sysctl_createv(clog, 0, NULL, NULL, 1617 CTLFLAG_PERMANENT, 1618 CTLTYPE_NODE, "inet", 1619 SYSCTL_DESCR("PF_INET related settings"), 1620 NULL, 0, NULL, 0, 1621 CTL_NET, PF_INET, CTL_EOL); 1622 sysctl_createv(clog, 0, NULL, NULL, 1623 CTLFLAG_PERMANENT, 1624 CTLTYPE_NODE, "ip", 1625 SYSCTL_DESCR("IPv4 related settings"), 1626 NULL, 0, NULL, 0, 1627 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL); 1628 1629 sysctl_createv(clog, 0, NULL, NULL, 1630 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1631 CTLTYPE_INT, "forwarding", 1632 SYSCTL_DESCR("Enable forwarding of INET datagrams"), 1633 NULL, 0, &ipforwarding, 0, 1634 CTL_NET, PF_INET, IPPROTO_IP, 1635 IPCTL_FORWARDING, CTL_EOL); 1636 sysctl_createv(clog, 0, NULL, NULL, 1637 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1638 CTLTYPE_INT, "redirect", 1639 SYSCTL_DESCR("Enable sending of ICMP redirect messages"), 1640 NULL, 0, &ipsendredirects, 0, 1641 CTL_NET, PF_INET, IPPROTO_IP, 1642 IPCTL_SENDREDIRECTS, CTL_EOL); 1643 sysctl_createv(clog, 0, NULL, NULL, 1644 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1645 CTLTYPE_INT, "ttl", 1646 SYSCTL_DESCR("Default TTL for an INET datagram"), 1647 NULL, 0, &ip_defttl, 0, 1648 CTL_NET, PF_INET, IPPROTO_IP, 1649 IPCTL_DEFTTL, CTL_EOL); 1650#ifdef IPCTL_DEFMTU 1651 sysctl_createv(clog, 0, NULL, NULL, 1652 CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */, 1653 CTLTYPE_INT, "mtu", 1654 SYSCTL_DESCR("Default MTA for an INET route"), 1655 NULL, 0, &ip_mtu, 0, 1656 CTL_NET, PF_INET, IPPROTO_IP, 1657 IPCTL_DEFMTU, CTL_EOL); 1658#endif /* IPCTL_DEFMTU */ 1659 sysctl_createv(clog, 0, NULL, NULL, 1660 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1661 CTLTYPE_INT, "forwsrcrt", 1662 SYSCTL_DESCR("Enable forwarding of source-routed " 1663 "datagrams"), 1664 sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0, 1665 CTL_NET, PF_INET, IPPROTO_IP, 1666 IPCTL_FORWSRCRT, CTL_EOL); 1667 sysctl_createv(clog, 0, NULL, NULL, 1668 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1669 CTLTYPE_INT, "directed-broadcast", 1670 SYSCTL_DESCR("Enable forwarding of broadcast datagrams"), 1671 NULL, 0, &ip_directedbcast, 0, 1672 CTL_NET, PF_INET, IPPROTO_IP, 1673 IPCTL_DIRECTEDBCAST, CTL_EOL); 1674 sysctl_createv(clog, 0, NULL, NULL, 1675 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1676 CTLTYPE_INT, "allowsrcrt", 1677 SYSCTL_DESCR("Accept source-routed datagrams"), 1678 NULL, 0, &ip_allowsrcrt, 0, 1679 CTL_NET, PF_INET, IPPROTO_IP, 1680 IPCTL_ALLOWSRCRT, CTL_EOL); 1681 1682 sysctl_createv(clog, 0, NULL, NULL, 1683 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1684 CTLTYPE_INT, "mtudisc", 1685 SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"), 1686 NULL, 0, &ip_mtudisc, 0, 1687 CTL_NET, PF_INET, IPPROTO_IP, 1688 IPCTL_MTUDISC, CTL_EOL); 1689 sysctl_createv(clog, 0, NULL, NULL, 1690 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1691 CTLTYPE_INT, "anonportmin", 1692 SYSCTL_DESCR("Lowest ephemeral port number to assign"), 1693 sysctl_net_inet_ip_ports, 0, &anonportmin, 0, 1694 CTL_NET, PF_INET, IPPROTO_IP, 1695 IPCTL_ANONPORTMIN, CTL_EOL); 1696 sysctl_createv(clog, 0, NULL, NULL, 1697 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1698 CTLTYPE_INT, "anonportmax", 1699 SYSCTL_DESCR("Highest ephemeral port number to assign"), 1700 sysctl_net_inet_ip_ports, 0, &anonportmax, 0, 1701 CTL_NET, PF_INET, IPPROTO_IP, 1702 IPCTL_ANONPORTMAX, CTL_EOL); 1703 sysctl_createv(clog, 0, NULL, NULL, 1704 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1705 CTLTYPE_INT, "mtudisctimeout", 1706 SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"), 1707 sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0, 1708 CTL_NET, PF_INET, IPPROTO_IP, 1709 IPCTL_MTUDISCTIMEOUT, CTL_EOL); 1710#ifndef IPNOPRIVPORTS 1711 sysctl_createv(clog, 0, NULL, NULL, 1712 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1713 CTLTYPE_INT, "lowportmin", 1714 SYSCTL_DESCR("Lowest privileged ephemeral port number " 1715 "to assign"), 1716 sysctl_net_inet_ip_ports, 0, &lowportmin, 0, 1717 CTL_NET, PF_INET, IPPROTO_IP, 1718 IPCTL_LOWPORTMIN, CTL_EOL); 1719 sysctl_createv(clog, 0, NULL, NULL, 1720 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1721 CTLTYPE_INT, "lowportmax", 1722 SYSCTL_DESCR("Highest privileged ephemeral port number " 1723 "to assign"), 1724 sysctl_net_inet_ip_ports, 0, &lowportmax, 0, 1725 CTL_NET, PF_INET, IPPROTO_IP, 1726 IPCTL_LOWPORTMAX, CTL_EOL); 1727#endif /* IPNOPRIVPORTS */ 1728#if NGRE > 0 1729 sysctl_createv(clog, 0, NULL, NULL, 1730 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1731 CTLTYPE_INT, "grettl", 1732 SYSCTL_DESCR("Default TTL for a gre tunnel datagram"), 1733 NULL, 0, &ip_gre_ttl, 0, 1734 CTL_NET, PF_INET, IPPROTO_IP, 1735 IPCTL_GRE_TTL, CTL_EOL); 1736#endif /* NGRE */ 1737 sysctl_createv(clog, 0, NULL, NULL, 1738 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1739 CTLTYPE_INT, "checkinterface", 1740 SYSCTL_DESCR("Enable receive side of Strong ES model " 1741 "from RFC1122"), 1742 NULL, 0, &ip_checkinterface, 0, 1743 CTL_NET, PF_INET, IPPROTO_IP, 1744 IPCTL_CHECKINTERFACE, CTL_EOL); 1745 sysctl_createv(clog, 0, NULL, NULL, 1746 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1747 CTLTYPE_INT, "random_id", 1748 SYSCTL_DESCR("Assign random ip_id values"), 1749 NULL, 0, &ip_do_randomid, 0, 1750 CTL_NET, PF_INET, IPPROTO_IP, 1751 IPCTL_RANDOMID, CTL_EOL); 1752 sysctl_createv(clog, 0, NULL, NULL, 1753 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1754 CTLTYPE_INT, "do_loopback_cksum", 1755 SYSCTL_DESCR("Perform IP checksum on loopback"), 1756 NULL, 0, &ip_do_loopback_cksum, 0, 1757 CTL_NET, PF_INET, IPPROTO_IP, 1758 IPCTL_LOOPBACKCKSUM, CTL_EOL); 1759 sysctl_createv(clog, 0, NULL, NULL, 1760 CTLFLAG_PERMANENT, 1761 CTLTYPE_STRUCT, "stats", 1762 SYSCTL_DESCR("IP statistics"), 1763 sysctl_net_inet_ip_stats, 0, NULL, 0, 1764 CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS, 1765 CTL_EOL); 1766#if NARP 1767 sysctl_createv(clog, 0, NULL, NULL, 1768 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1769 CTLTYPE_INT, "dad_count", 1770 SYSCTL_DESCR("Number of Duplicate Address Detection " 1771 "probes to send"), 1772 NULL, 0, &ip_dad_count, 0, 1773 CTL_NET, PF_INET, IPPROTO_IP, 1774 IPCTL_DAD_COUNT, CTL_EOL); 1775#endif 1776 1777 /* anonportalgo RFC6056 subtree */ 1778 const struct sysctlnode *portalgo_node; 1779 sysctl_createv(clog, 0, NULL, &portalgo_node, 1780 CTLFLAG_PERMANENT, 1781 CTLTYPE_NODE, "anonportalgo", 1782 SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"), 1783 NULL, 0, NULL, 0, 1784 CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL); 1785 sysctl_createv(clog, 0, &portalgo_node, NULL, 1786 CTLFLAG_PERMANENT, 1787 CTLTYPE_STRING, "available", 1788 SYSCTL_DESCR("available algorithms"), 1789 sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN, 1790 CTL_CREATE, CTL_EOL); 1791 sysctl_createv(clog, 0, &portalgo_node, NULL, 1792 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1793 CTLTYPE_STRING, "selected", 1794 SYSCTL_DESCR("selected algorithm"), 1795 sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN, 1796 CTL_CREATE, CTL_EOL); 1797 sysctl_createv(clog, 0, &portalgo_node, NULL, 1798 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1799 CTLTYPE_STRUCT, "reserve", 1800 SYSCTL_DESCR("bitmap of reserved ports"), 1801 sysctl_portalgo_reserve4, 0, NULL, 0, 1802 CTL_CREATE, CTL_EOL); 1803} 1804 1805void 1806ip_statinc(u_int stat) 1807{ 1808 1809 KASSERT(stat < IP_NSTATS); 1810 IP_STATINC(stat); 1811} 1812