ip_input.c revision 1.340
1/* $NetBSD: ip_input.c,v 1.340 2016/08/31 09:14:47 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 1.340 2016/08/31 09:14:47 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 break; 387 else 388 (*downmatch)++; 389 } 390 } 391 392 return ia; 393} 394 395static struct in_ifaddr * 396ip_match_our_address_broadcast(struct ifnet *ifp, struct ip *ip) 397{ 398 struct in_ifaddr *ia = NULL; 399 struct ifaddr *ifa; 400 401 IFADDR_READER_FOREACH(ifa, ifp) { 402 if (ifa->ifa_addr->sa_family != AF_INET) 403 continue; 404 ia = ifatoia(ifa); 405 if (ia->ia4_flags & IN_IFF_NOTREADY) 406 continue; 407 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 408 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 409 /* 410 * Look for all-0's host part (old broadcast addr), 411 * either for subnet or net. 412 */ 413 ip->ip_dst.s_addr == ia->ia_subnet || 414 ip->ip_dst.s_addr == ia->ia_net) 415 goto matched; 416 /* 417 * An interface with IP address zero accepts 418 * all packets that arrive on that interface. 419 */ 420 if (in_nullhost(ia->ia_addr.sin_addr)) 421 goto matched; 422 } 423 ia = NULL; 424 425matched: 426 return ia; 427} 428 429/* 430 * IP software interrupt routine. 431 */ 432static void 433ipintr(void *arg __unused) 434{ 435 struct mbuf *m; 436 437 KASSERT(cpu_softintr_p()); 438 439 mutex_enter(softnet_lock); 440 while ((m = pktq_dequeue(ip_pktq)) != NULL) { 441 ip_input(m); 442 } 443 mutex_exit(softnet_lock); 444} 445 446/* 447 * IP input routine. Checksum and byte swap header. If fragmented 448 * try to reassemble. Process options. Pass to next level. 449 */ 450static void 451ip_input(struct mbuf *m) 452{ 453 struct ip *ip = NULL; 454 struct in_ifaddr *ia = NULL; 455 int hlen = 0, len; 456 int downmatch; 457 int srcrt = 0; 458 ifnet_t *ifp; 459 struct psref psref; 460 int s; 461 462 KASSERTMSG(cpu_softintr_p(), "ip_input: not in the software " 463 "interrupt handler; synchronization assumptions violated"); 464 465 MCLAIM(m, &ip_rx_mowner); 466 KASSERT((m->m_flags & M_PKTHDR) != 0); 467 468 ifp = m_get_rcvif_psref(m, &psref); 469 if (__predict_false(ifp == NULL)) 470 goto out; 471 472 /* 473 * If no IP addresses have been set yet but the interfaces 474 * are receiving, can't do anything with incoming packets yet. 475 * Note: we pre-check without locks held. 476 */ 477 if (IN_ADDRLIST_READER_EMPTY()) 478 goto out; 479 IP_STATINC(IP_STAT_TOTAL); 480 481 /* 482 * If the IP header is not aligned, slurp it up into a new 483 * mbuf with space for link headers, in the event we forward 484 * it. Otherwise, if it is aligned, make sure the entire 485 * base IP header is in the first mbuf of the chain. 486 */ 487 if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) { 488 if ((m = m_copyup(m, sizeof(struct ip), 489 (max_linkhdr + 3) & ~3)) == NULL) { 490 /* XXXJRT new stat, please */ 491 IP_STATINC(IP_STAT_TOOSMALL); 492 goto out; 493 } 494 } else if (__predict_false(m->m_len < sizeof (struct ip))) { 495 if ((m = m_pullup(m, sizeof (struct ip))) == NULL) { 496 IP_STATINC(IP_STAT_TOOSMALL); 497 goto out; 498 } 499 } 500 ip = mtod(m, struct ip *); 501 if (ip->ip_v != IPVERSION) { 502 IP_STATINC(IP_STAT_BADVERS); 503 goto out; 504 } 505 hlen = ip->ip_hl << 2; 506 if (hlen < sizeof(struct ip)) { /* minimum header length */ 507 IP_STATINC(IP_STAT_BADHLEN); 508 goto out; 509 } 510 if (hlen > m->m_len) { 511 if ((m = m_pullup(m, hlen)) == NULL) { 512 IP_STATINC(IP_STAT_BADHLEN); 513 goto out; 514 } 515 ip = mtod(m, struct ip *); 516 } 517 518 /* 519 * RFC1122: packets with a multicast source address are 520 * not allowed. 521 */ 522 if (IN_MULTICAST(ip->ip_src.s_addr)) { 523 IP_STATINC(IP_STAT_BADADDR); 524 goto out; 525 } 526 527 /* 127/8 must not appear on wire - RFC1122 */ 528 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 529 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 530 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 531 IP_STATINC(IP_STAT_BADADDR); 532 goto out; 533 } 534 } 535 536 switch (m->m_pkthdr.csum_flags & 537 ((ifp->if_csum_flags_rx & M_CSUM_IPv4) | 538 M_CSUM_IPv4_BAD)) { 539 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 540 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad); 541 IP_STATINC(IP_STAT_BADSUM); 542 goto out; 543 544 case M_CSUM_IPv4: 545 /* Checksum was okay. */ 546 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok); 547 break; 548 549 default: 550 /* 551 * Must compute it ourselves. Maybe skip checksum on 552 * loopback interfaces. 553 */ 554 if (__predict_true(!(ifp->if_flags & IFF_LOOPBACK) || 555 ip_do_loopback_cksum)) { 556 INET_CSUM_COUNTER_INCR(&ip_swcsum); 557 if (in_cksum(m, hlen) != 0) { 558 IP_STATINC(IP_STAT_BADSUM); 559 goto out; 560 } 561 } 562 break; 563 } 564 565 /* Retrieve the packet length. */ 566 len = ntohs(ip->ip_len); 567 568 /* 569 * Check for additional length bogosity 570 */ 571 if (len < hlen) { 572 IP_STATINC(IP_STAT_BADLEN); 573 goto out; 574 } 575 576 /* 577 * Check that the amount of data in the buffers 578 * is as at least much as the IP header would have us expect. 579 * Trim mbufs if longer than we expect. 580 * Drop packet if shorter than we expect. 581 */ 582 if (m->m_pkthdr.len < len) { 583 IP_STATINC(IP_STAT_TOOSHORT); 584 goto out; 585 } 586 if (m->m_pkthdr.len > len) { 587 if (m->m_len == m->m_pkthdr.len) { 588 m->m_len = len; 589 m->m_pkthdr.len = len; 590 } else 591 m_adj(m, len - m->m_pkthdr.len); 592 } 593 594 /* 595 * Assume that we can create a fast-forward IP flow entry 596 * based on this packet. 597 */ 598 m->m_flags |= M_CANFASTFWD; 599 600 /* 601 * Run through list of hooks for input packets. If there are any 602 * filters which require that additional packets in the flow are 603 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 604 * Note that filters must _never_ set this flag, as another filter 605 * in the list may have previously cleared it. 606 */ 607#if defined(IPSEC) 608 if (!ipsec_used || !ipsec_indone(m)) 609#else 610 if (1) 611#endif 612 { 613 struct in_addr odst = ip->ip_dst; 614 bool freed; 615 616 SOFTNET_LOCK(); 617 freed = pfil_run_hooks(inet_pfil_hook, &m, ifp, PFIL_IN) != 0; 618 SOFTNET_UNLOCK(); 619 if (freed || m == NULL) { 620 goto out; 621 } 622 ip = mtod(m, struct ip *); 623 hlen = ip->ip_hl << 2; 624 625 /* 626 * XXX The setting of "srcrt" here is to prevent ip_forward() 627 * from generating ICMP redirects for packets that have 628 * been redirected by a hook back out on to the same LAN that 629 * they came from and is not an indication that the packet 630 * is being inffluenced by source routing options. This 631 * allows things like 632 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp" 633 * where tlp0 is both on the 1.1.1.0/24 network and is the 634 * default route for hosts on 1.1.1.0/24. Of course this 635 * also requires a "map tlp0 ..." to complete the story. 636 * One might argue whether or not this kind of network config. 637 * should be supported in this manner... 638 */ 639 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 640 } 641 642#ifdef ALTQ 643 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 644 if (altq_input) { 645 SOFTNET_LOCK(); 646 if ((*altq_input)(m, AF_INET) == 0) { 647 /* Packet dropped by traffic conditioner. */ 648 SOFTNET_UNLOCK(); 649 goto out; 650 } 651 SOFTNET_UNLOCK(); 652 } 653#endif 654 655 /* 656 * Process options and, if not destined for us, 657 * ship it on. ip_dooptions returns 1 when an 658 * error was detected (causing an icmp message 659 * to be sent and the original packet to be freed). 660 */ 661 ip_nhops = 0; /* for source routed packets */ 662 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 663 goto out; 664 665 /* 666 * Check our list of addresses, to see if the packet is for us. 667 * 668 * Traditional 4.4BSD did not consult IFF_UP at all. 669 * The behavior here is to treat addresses on !IFF_UP interface 670 * or IN_IFF_NOTREADY addresses as not mine. 671 */ 672 downmatch = 0; 673 s = pserialize_read_enter(); 674 ia = ip_match_our_address(ifp, ip, &downmatch); 675 if (ia != NULL) { 676 pserialize_read_exit(s); 677 goto ours; 678 } 679 680 if (ifp->if_flags & IFF_BROADCAST) { 681 ia = ip_match_our_address_broadcast(ifp, ip); 682 if (ia != NULL) { 683 pserialize_read_exit(s); 684 goto ours; 685 } 686 } 687 pserialize_read_exit(s); 688 689 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 690#ifdef MROUTING 691 extern struct socket *ip_mrouter; 692 693 if (ip_mrouter) { 694 /* 695 * If we are acting as a multicast router, all 696 * incoming multicast packets are passed to the 697 * kernel-level multicast forwarding function. 698 * The packet is returned (relatively) intact; if 699 * ip_mforward() returns a non-zero value, the packet 700 * must be discarded, else it may be accepted below. 701 * 702 * (The IP ident field is put in the same byte order 703 * as expected when ip_mforward() is called from 704 * ip_output().) 705 */ 706 SOFTNET_LOCK(); 707 if (ip_mforward(m, ifp) != 0) { 708 SOFTNET_UNLOCK(); 709 IP_STATINC(IP_STAT_CANTFORWARD); 710 goto out; 711 } 712 SOFTNET_UNLOCK(); 713 714 /* 715 * The process-level routing demon needs to receive 716 * all multicast IGMP packets, whether or not this 717 * host belongs to their destination groups. 718 */ 719 if (ip->ip_p == IPPROTO_IGMP) { 720 goto ours; 721 } 722 IP_STATINC(IP_STAT_CANTFORWARD); 723 } 724#endif 725 /* 726 * See if we belong to the destination multicast group on the 727 * arrival interface. 728 */ 729 if (!in_multi_group(ip->ip_dst, ifp, 0)) { 730 IP_STATINC(IP_STAT_CANTFORWARD); 731 goto out; 732 } 733 goto ours; 734 } 735 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 736 in_nullhost(ip->ip_dst)) 737 goto ours; 738 739 /* 740 * Not for us; forward if possible and desirable. 741 */ 742 if (ipforwarding == 0) { 743 m_put_rcvif_psref(ifp, &psref); 744 IP_STATINC(IP_STAT_CANTFORWARD); 745 m_freem(m); 746 } else { 747 /* 748 * If ip_dst matched any of my address on !IFF_UP interface, 749 * and there's no IFF_UP interface that matches ip_dst, 750 * send icmp unreach. Forwarding it will result in in-kernel 751 * forwarding loop till TTL goes to 0. 752 */ 753 if (downmatch) { 754 m_put_rcvif_psref(ifp, &psref); 755 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 756 IP_STATINC(IP_STAT_CANTFORWARD); 757 return; 758 } 759#ifdef IPSEC 760 /* Perform IPsec, if any. */ 761 if (ipsec_used) { 762 SOFTNET_LOCK(); 763 if (ipsec4_input(m, IP_FORWARDING | 764 (ip_directedbcast ? IP_ALLOWBROADCAST : 0)) != 0) { 765 SOFTNET_UNLOCK(); 766 goto out; 767 } 768 SOFTNET_UNLOCK(); 769 } 770#endif 771 ip_forward(m, srcrt, ifp); 772 m_put_rcvif_psref(ifp, &psref); 773 } 774 return; 775 776ours: 777 m_put_rcvif_psref(ifp, &psref); 778 ifp = NULL; 779 780 /* 781 * If offset or IP_MF are set, must reassemble. 782 */ 783 if (ip->ip_off & ~htons(IP_DF|IP_RF)) { 784 /* 785 * Pass to IP reassembly mechanism. 786 */ 787 if (ip_reass_packet(&m, ip) != 0) { 788 /* Failed; invalid fragment(s) or packet. */ 789 goto out; 790 } 791 if (m == NULL) { 792 /* More fragments should come; silently return. */ 793 goto out; 794 } 795 /* 796 * Reassembly is done, we have the final packet. 797 * Updated cached data in local variable(s). 798 */ 799 ip = mtod(m, struct ip *); 800 hlen = ip->ip_hl << 2; 801 } 802 803#ifdef IPSEC 804 /* 805 * Enforce IPsec policy checking if we are seeing last header. 806 * Note that we do not visit this with protocols with PCB layer 807 * code - like UDP/TCP/raw IP. 808 */ 809 if (ipsec_used && 810 (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 811 SOFTNET_LOCK(); 812 if (ipsec4_input(m, 0) != 0) { 813 SOFTNET_UNLOCK(); 814 goto out; 815 } 816 SOFTNET_UNLOCK(); 817 } 818#endif 819 820 /* 821 * Switch out to protocol's input routine. 822 */ 823#if IFA_STATS 824 if (ia && ip) { 825 struct in_ifaddr *_ia; 826 /* 827 * Keep a reference from ip_match_our_address with psref 828 * is expensive, so explore ia here again. 829 */ 830 s = pserialize_read_enter(); 831 _ia = in_get_ia(ip->ip_dst.s_addr); 832 _ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len); 833 pserialize_read_exit(s); 834 } 835#endif 836 IP_STATINC(IP_STAT_DELIVERED); 837 838 const int off = hlen, nh = ip->ip_p; 839 840 SOFTNET_LOCK(); 841 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 842 SOFTNET_UNLOCK(); 843 return; 844 845out: 846 m_put_rcvif_psref(ifp, &psref); 847 if (m != NULL) 848 m_freem(m); 849} 850 851/* 852 * IP timer processing. 853 */ 854void 855ip_slowtimo(void) 856{ 857 858 mutex_enter(softnet_lock); 859 KERNEL_LOCK(1, NULL); 860 861 ip_reass_slowtimo(); 862 863 KERNEL_UNLOCK_ONE(NULL); 864 mutex_exit(softnet_lock); 865} 866 867/* 868 * IP drain processing. 869 */ 870void 871ip_drain(void) 872{ 873 874 KERNEL_LOCK(1, NULL); 875 ip_reass_drain(); 876 KERNEL_UNLOCK_ONE(NULL); 877} 878 879/* 880 * ip_dooptions: perform option processing on a datagram, possibly discarding 881 * it if bad options are encountered, or forwarding it if source-routed. 882 * 883 * => Returns true if packet has been forwarded/freed. 884 * => Returns false if the packet should be processed further. 885 */ 886static bool 887ip_dooptions(struct mbuf *m) 888{ 889 struct ip *ip = mtod(m, struct ip *); 890 u_char *cp, *cp0; 891 struct ip_timestamp *ipt; 892 struct in_ifaddr *ia; 893 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 894 struct in_addr dst; 895 n_time ntime; 896 struct ifaddr *ifa; 897 int s; 898 899 dst = ip->ip_dst; 900 cp = (u_char *)(ip + 1); 901 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 902 for (; cnt > 0; cnt -= optlen, cp += optlen) { 903 opt = cp[IPOPT_OPTVAL]; 904 if (opt == IPOPT_EOL) 905 break; 906 if (opt == IPOPT_NOP) 907 optlen = 1; 908 else { 909 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 910 code = &cp[IPOPT_OLEN] - (u_char *)ip; 911 goto bad; 912 } 913 optlen = cp[IPOPT_OLEN]; 914 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 915 code = &cp[IPOPT_OLEN] - (u_char *)ip; 916 goto bad; 917 } 918 } 919 switch (opt) { 920 921 default: 922 break; 923 924 /* 925 * Source routing with record. 926 * Find interface with current destination address. 927 * If none on this machine then drop if strictly routed, 928 * or do nothing if loosely routed. 929 * Record interface address and bring up next address 930 * component. If strictly routed make sure next 931 * address is on directly accessible net. 932 */ 933 case IPOPT_LSRR: 934 case IPOPT_SSRR: 935 if (ip_allowsrcrt == 0) { 936 type = ICMP_UNREACH; 937 code = ICMP_UNREACH_NET_PROHIB; 938 goto bad; 939 } 940 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 941 code = &cp[IPOPT_OLEN] - (u_char *)ip; 942 goto bad; 943 } 944 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 945 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 946 goto bad; 947 } 948 ipaddr.sin_addr = ip->ip_dst; 949 950 s = pserialize_read_enter(); 951 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 952 if (ifa == NULL) { 953 pserialize_read_exit(s); 954 if (opt == IPOPT_SSRR) { 955 type = ICMP_UNREACH; 956 code = ICMP_UNREACH_SRCFAIL; 957 goto bad; 958 } 959 /* 960 * Loose routing, and not at next destination 961 * yet; nothing to do except forward. 962 */ 963 break; 964 } 965 pserialize_read_exit(s); 966 967 off--; /* 0 origin */ 968 if ((off + sizeof(struct in_addr)) > optlen) { 969 /* 970 * End of source route. Should be for us. 971 */ 972 save_rte(cp, ip->ip_src); 973 break; 974 } 975 /* 976 * locate outgoing interface 977 */ 978 memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off), 979 sizeof(ipaddr.sin_addr)); 980 s = pserialize_read_enter(); 981 if (opt == IPOPT_SSRR) { 982 ifa = ifa_ifwithladdr(sintosa(&ipaddr)); 983 if (ifa != NULL) 984 ia = ifatoia(ifa); 985 else 986 ia = NULL; 987 } else { 988 ia = ip_rtaddr(ipaddr.sin_addr); 989 } 990 if (ia == NULL) { 991 type = ICMP_UNREACH; 992 code = ICMP_UNREACH_SRCFAIL; 993 pserialize_read_exit(s); 994 goto bad; 995 } 996 ip->ip_dst = ipaddr.sin_addr; 997 bcopy((void *)&ia->ia_addr.sin_addr, 998 (void *)(cp + off), sizeof(struct in_addr)); 999 pserialize_read_exit(s); 1000 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1001 /* 1002 * Let ip_intr's mcast routing check handle mcast pkts 1003 */ 1004 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1005 break; 1006 1007 case IPOPT_RR: 1008 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1009 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1010 goto bad; 1011 } 1012 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1013 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1014 goto bad; 1015 } 1016 /* 1017 * If no space remains, ignore. 1018 */ 1019 off--; /* 0 origin */ 1020 if ((off + sizeof(struct in_addr)) > optlen) 1021 break; 1022 memcpy((void *)&ipaddr.sin_addr, (void *)(&ip->ip_dst), 1023 sizeof(ipaddr.sin_addr)); 1024 /* 1025 * locate outgoing interface; if we're the destination, 1026 * use the incoming interface (should be same). 1027 */ 1028 s = pserialize_read_enter(); 1029 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 1030 if (ifa == NULL) { 1031 ia = ip_rtaddr(ipaddr.sin_addr); 1032 if (ia == NULL) { 1033 pserialize_read_exit(s); 1034 type = ICMP_UNREACH; 1035 code = ICMP_UNREACH_HOST; 1036 goto bad; 1037 } 1038 } else { 1039 ia = ifatoia(ifa); 1040 } 1041 bcopy((void *)&ia->ia_addr.sin_addr, 1042 (void *)(cp + off), sizeof(struct in_addr)); 1043 pserialize_read_exit(s); 1044 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1045 break; 1046 1047 case IPOPT_TS: 1048 code = cp - (u_char *)ip; 1049 ipt = (struct ip_timestamp *)cp; 1050 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1051 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1052 goto bad; 1053 } 1054 if (ipt->ipt_ptr < 5) { 1055 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1056 goto bad; 1057 } 1058 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) { 1059 if (++ipt->ipt_oflw == 0) { 1060 code = (u_char *)&ipt->ipt_ptr - 1061 (u_char *)ip; 1062 goto bad; 1063 } 1064 break; 1065 } 1066 cp0 = (cp + ipt->ipt_ptr - 1); 1067 switch (ipt->ipt_flg) { 1068 1069 case IPOPT_TS_TSONLY: 1070 break; 1071 1072 case IPOPT_TS_TSANDADDR: { 1073 struct ifnet *rcvif; 1074 int _s, _ss; 1075 1076 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1077 sizeof(struct in_addr) > ipt->ipt_len) { 1078 code = (u_char *)&ipt->ipt_ptr - 1079 (u_char *)ip; 1080 goto bad; 1081 } 1082 ipaddr.sin_addr = dst; 1083 _ss = pserialize_read_enter(); 1084 rcvif = m_get_rcvif(m, &_s); 1085 ifa = ifaof_ifpforaddr(sintosa(&ipaddr), rcvif); 1086 m_put_rcvif(rcvif, &_s); 1087 if (ifa == NULL) { 1088 pserialize_read_exit(_ss); 1089 break; 1090 } 1091 ia = ifatoia(ifa); 1092 bcopy(&ia->ia_addr.sin_addr, 1093 cp0, sizeof(struct in_addr)); 1094 pserialize_read_exit(_ss); 1095 ipt->ipt_ptr += sizeof(struct in_addr); 1096 break; 1097 } 1098 1099 case IPOPT_TS_PRESPEC: 1100 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1101 sizeof(struct in_addr) > ipt->ipt_len) { 1102 code = (u_char *)&ipt->ipt_ptr - 1103 (u_char *)ip; 1104 goto bad; 1105 } 1106 memcpy(&ipaddr.sin_addr, cp0, 1107 sizeof(struct in_addr)); 1108 s = pserialize_read_enter(); 1109 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 1110 if (ifa == NULL) { 1111 pserialize_read_exit(s); 1112 continue; 1113 } 1114 pserialize_read_exit(s); 1115 ipt->ipt_ptr += sizeof(struct in_addr); 1116 break; 1117 1118 default: 1119 /* XXX can't take &ipt->ipt_flg */ 1120 code = (u_char *)&ipt->ipt_ptr - 1121 (u_char *)ip + 1; 1122 goto bad; 1123 } 1124 ntime = iptime(); 1125 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1126 memmove((char *)cp + ipt->ipt_ptr - 1, cp0, 1127 sizeof(n_time)); 1128 ipt->ipt_ptr += sizeof(n_time); 1129 } 1130 } 1131 if (forward) { 1132 struct ifnet *rcvif; 1133 struct psref _psref; 1134 1135 if (ip_forwsrcrt == 0) { 1136 type = ICMP_UNREACH; 1137 code = ICMP_UNREACH_SRCFAIL; 1138 goto bad; 1139 } 1140 1141 rcvif = m_get_rcvif_psref(m, &_psref); 1142 if (__predict_false(rcvif == NULL)) { 1143 type = ICMP_UNREACH; 1144 code = ICMP_UNREACH_HOST; 1145 goto bad; 1146 } 1147 ip_forward(m, 1, rcvif); 1148 m_put_rcvif_psref(rcvif, &_psref); 1149 return true; 1150 } 1151 return false; 1152bad: 1153 icmp_error(m, type, code, 0, 0); 1154 IP_STATINC(IP_STAT_BADOPTIONS); 1155 return true; 1156} 1157 1158/* 1159 * ip_rtaddr: given address of next destination (final or next hop), 1160 * return internet address info of interface to be used to get there. 1161 */ 1162static struct in_ifaddr * 1163ip_rtaddr(struct in_addr dst) 1164{ 1165 struct rtentry *rt; 1166 union { 1167 struct sockaddr dst; 1168 struct sockaddr_in dst4; 1169 } u; 1170 struct route *ro; 1171 1172 sockaddr_in_init(&u.dst4, &dst, 0); 1173 1174 SOFTNET_LOCK(); 1175 ro = percpu_getref(ipforward_rt_percpu); 1176 rt = rtcache_lookup(ro, &u.dst); 1177 percpu_putref(ipforward_rt_percpu); 1178 SOFTNET_UNLOCK(); 1179 if (rt == NULL) 1180 return NULL; 1181 1182 return ifatoia(rt->rt_ifa); 1183} 1184 1185/* 1186 * save_rte: save incoming source route for use in replies, to be picked 1187 * up later by ip_srcroute if the receiver is interested. 1188 */ 1189static void 1190save_rte(u_char *option, struct in_addr dst) 1191{ 1192 unsigned olen; 1193 1194 olen = option[IPOPT_OLEN]; 1195 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1196 return; 1197 memcpy((void *)ip_srcrt.srcopt, (void *)option, olen); 1198 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1199 ip_srcrt.dst = dst; 1200} 1201 1202/* 1203 * Retrieve incoming source route for use in replies, 1204 * in the same form used by setsockopt. 1205 * The first hop is placed before the options, will be removed later. 1206 */ 1207struct mbuf * 1208ip_srcroute(void) 1209{ 1210 struct in_addr *p, *q; 1211 struct mbuf *m; 1212 1213 if (ip_nhops == 0) 1214 return NULL; 1215 m = m_get(M_DONTWAIT, MT_SOOPTS); 1216 if (m == 0) 1217 return NULL; 1218 1219 MCLAIM(m, &inetdomain.dom_mowner); 1220#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1221 1222 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1223 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1224 OPTSIZ; 1225 1226 /* 1227 * First save first hop for return route 1228 */ 1229 p = &ip_srcrt.route[ip_nhops - 1]; 1230 *(mtod(m, struct in_addr *)) = *p--; 1231 1232 /* 1233 * Copy option fields and padding (nop) to mbuf. 1234 */ 1235 ip_srcrt.nop = IPOPT_NOP; 1236 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1237 memmove(mtod(m, char *) + sizeof(struct in_addr), &ip_srcrt.nop, 1238 OPTSIZ); 1239 q = (struct in_addr *)(mtod(m, char *) + 1240 sizeof(struct in_addr) + OPTSIZ); 1241#undef OPTSIZ 1242 /* 1243 * Record return path as an IP source route, 1244 * reversing the path (pointers are now aligned). 1245 */ 1246 while (p >= ip_srcrt.route) { 1247 *q++ = *p--; 1248 } 1249 /* 1250 * Last hop goes to final destination. 1251 */ 1252 *q = ip_srcrt.dst; 1253 return (m); 1254} 1255 1256const int inetctlerrmap[PRC_NCMDS] = { 1257 [PRC_MSGSIZE] = EMSGSIZE, 1258 [PRC_HOSTDEAD] = EHOSTDOWN, 1259 [PRC_HOSTUNREACH] = EHOSTUNREACH, 1260 [PRC_UNREACH_NET] = EHOSTUNREACH, 1261 [PRC_UNREACH_HOST] = EHOSTUNREACH, 1262 [PRC_UNREACH_PROTOCOL] = ECONNREFUSED, 1263 [PRC_UNREACH_PORT] = ECONNREFUSED, 1264 [PRC_UNREACH_SRCFAIL] = EHOSTUNREACH, 1265 [PRC_PARAMPROB] = ENOPROTOOPT, 1266}; 1267 1268void 1269ip_fasttimo(void) 1270{ 1271 if (ip_drainwanted) { 1272 ip_drain(); 1273 ip_drainwanted = 0; 1274 } 1275} 1276 1277void 1278ip_drainstub(void) 1279{ 1280 ip_drainwanted = 1; 1281} 1282 1283/* 1284 * Forward a packet. If some error occurs return the sender 1285 * an icmp packet. Note we can't always generate a meaningful 1286 * icmp message because icmp doesn't have a large enough repertoire 1287 * of codes and types. 1288 * 1289 * If not forwarding, just drop the packet. This could be confusing 1290 * if ipforwarding was zero but some routing protocol was advancing 1291 * us as a gateway to somewhere. However, we must let the routing 1292 * protocol deal with that. 1293 * 1294 * The srcrt parameter indicates whether the packet is being forwarded 1295 * via a source route. 1296 */ 1297static void 1298ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif) 1299{ 1300 struct ip *ip = mtod(m, struct ip *); 1301 struct rtentry *rt; 1302 int error, type = 0, code = 0, destmtu = 0; 1303 struct mbuf *mcopy; 1304 n_long dest; 1305 union { 1306 struct sockaddr dst; 1307 struct sockaddr_in dst4; 1308 } u; 1309 uint64_t *ips; 1310 struct route *ro; 1311 1312 KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software " 1313 "interrupt handler; synchronization assumptions violated"); 1314 1315 /* 1316 * We are now in the output path. 1317 */ 1318 MCLAIM(m, &ip_tx_mowner); 1319 1320 /* 1321 * Clear any in-bound checksum flags for this packet. 1322 */ 1323 m->m_pkthdr.csum_flags = 0; 1324 1325 dest = 0; 1326 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1327 IP_STATINC(IP_STAT_CANTFORWARD); 1328 m_freem(m); 1329 return; 1330 } 1331 1332 SOFTNET_LOCK(); 1333 1334 if (ip->ip_ttl <= IPTTLDEC) { 1335 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1336 SOFTNET_UNLOCK(); 1337 return; 1338 } 1339 1340 sockaddr_in_init(&u.dst4, &ip->ip_dst, 0); 1341 1342 ro = percpu_getref(ipforward_rt_percpu); 1343 if ((rt = rtcache_lookup(ro, &u.dst)) == NULL) { 1344 percpu_putref(ipforward_rt_percpu); 1345 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0); 1346 SOFTNET_UNLOCK(); 1347 return; 1348 } 1349 1350 /* 1351 * Save at most 68 bytes of the packet in case 1352 * we need to generate an ICMP message to the src. 1353 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1354 */ 1355 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1356 if (mcopy) 1357 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1358 1359 ip->ip_ttl -= IPTTLDEC; 1360 1361 /* 1362 * If forwarding packet using same interface that it came in on, 1363 * perhaps should send a redirect to sender to shortcut a hop. 1364 * Only send redirect if source is sending directly to us, 1365 * and if packet was not source routed (or has any options). 1366 * Also, don't send redirect if forwarding using a default route 1367 * or a route modified by a redirect. 1368 */ 1369 if (rt->rt_ifp == rcvif && 1370 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1371 !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) && 1372 ipsendredirects && !srcrt) { 1373 if (rt->rt_ifa && 1374 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1375 ifatoia(rt->rt_ifa)->ia_subnet) { 1376 if (rt->rt_flags & RTF_GATEWAY) 1377 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1378 else 1379 dest = ip->ip_dst.s_addr; 1380 /* 1381 * Router requirements says to only send host 1382 * redirects. 1383 */ 1384 type = ICMP_REDIRECT; 1385 code = ICMP_REDIRECT_HOST; 1386 } 1387 } 1388 1389 error = ip_output(m, NULL, ro, 1390 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1391 NULL, NULL); 1392 1393 if (error) { 1394 IP_STATINC(IP_STAT_CANTFORWARD); 1395 goto error; 1396 } 1397 1398 ips = IP_STAT_GETREF(); 1399 ips[IP_STAT_FORWARD]++; 1400 1401 if (type) { 1402 ips[IP_STAT_REDIRECTSENT]++; 1403 IP_STAT_PUTREF(); 1404 goto redirect; 1405 } 1406 1407 IP_STAT_PUTREF(); 1408 if (mcopy) { 1409#ifdef GATEWAY 1410 if (mcopy->m_flags & M_CANFASTFWD) 1411 ipflow_create(ro, mcopy); 1412#endif 1413 m_freem(mcopy); 1414 } 1415 1416 percpu_putref(ipforward_rt_percpu); 1417 SOFTNET_UNLOCK(); 1418 return; 1419 1420redirect: 1421error: 1422 if (mcopy == NULL) { 1423 percpu_putref(ipforward_rt_percpu); 1424 SOFTNET_UNLOCK(); 1425 return; 1426 } 1427 1428 switch (error) { 1429 1430 case 0: /* forwarded, but need redirect */ 1431 /* type, code set above */ 1432 break; 1433 1434 case ENETUNREACH: /* shouldn't happen, checked above */ 1435 case EHOSTUNREACH: 1436 case ENETDOWN: 1437 case EHOSTDOWN: 1438 default: 1439 type = ICMP_UNREACH; 1440 code = ICMP_UNREACH_HOST; 1441 break; 1442 1443 case EMSGSIZE: 1444 type = ICMP_UNREACH; 1445 code = ICMP_UNREACH_NEEDFRAG; 1446 1447 if ((rt = rtcache_validate(ro)) != NULL) 1448 destmtu = rt->rt_ifp->if_mtu; 1449#ifdef IPSEC 1450 if (ipsec_used) 1451 (void)ipsec4_forward(mcopy, &destmtu); 1452#endif 1453 IP_STATINC(IP_STAT_CANTFRAG); 1454 break; 1455 1456 case ENOBUFS: 1457 /* 1458 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812, 1459 * Requirements for IP Version 4 Routers. Source quench can 1460 * big problem under DoS attacks or if the underlying 1461 * interface is rate-limited. 1462 */ 1463 if (mcopy) 1464 m_freem(mcopy); 1465 percpu_putref(ipforward_rt_percpu); 1466 SOFTNET_UNLOCK(); 1467 return; 1468 } 1469 icmp_error(mcopy, type, code, dest, destmtu); 1470 percpu_putref(ipforward_rt_percpu); 1471 SOFTNET_UNLOCK(); 1472} 1473 1474void 1475ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1476 struct mbuf *m) 1477{ 1478 struct socket *so = inp->inp_socket; 1479 ifnet_t *ifp; 1480 int inpflags = inp->inp_flags; 1481 struct psref psref; 1482 1483 ifp = m_get_rcvif_psref(m, &psref); 1484 if (__predict_false(ifp == NULL)) 1485 return; /* XXX should report error? */ 1486 1487 if (so->so_options & SO_TIMESTAMP 1488#ifdef SO_OTIMESTAMP 1489 || so->so_options & SO_OTIMESTAMP 1490#endif 1491 ) { 1492 struct timeval tv; 1493 1494 microtime(&tv); 1495#ifdef SO_OTIMESTAMP 1496 if (so->so_options & SO_OTIMESTAMP) { 1497 struct timeval50 tv50; 1498 timeval_to_timeval50(&tv, &tv50); 1499 *mp = sbcreatecontrol((void *) &tv50, sizeof(tv50), 1500 SCM_OTIMESTAMP, SOL_SOCKET); 1501 } else 1502#endif 1503 *mp = sbcreatecontrol((void *) &tv, sizeof(tv), 1504 SCM_TIMESTAMP, SOL_SOCKET); 1505 if (*mp) 1506 mp = &(*mp)->m_next; 1507 } 1508 if (inpflags & INP_RECVDSTADDR) { 1509 *mp = sbcreatecontrol((void *) &ip->ip_dst, 1510 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1511 if (*mp) 1512 mp = &(*mp)->m_next; 1513 } 1514 if (inpflags & INP_RECVPKTINFO) { 1515 struct in_pktinfo ipi; 1516 ipi.ipi_addr = ip->ip_src; 1517 ipi.ipi_ifindex = ifp->if_index; 1518 *mp = sbcreatecontrol((void *) &ipi, 1519 sizeof(ipi), IP_RECVPKTINFO, IPPROTO_IP); 1520 if (*mp) 1521 mp = &(*mp)->m_next; 1522 } 1523 if (inpflags & INP_PKTINFO) { 1524 struct in_pktinfo ipi; 1525 ipi.ipi_addr = ip->ip_dst; 1526 ipi.ipi_ifindex = ifp->if_index; 1527 *mp = sbcreatecontrol((void *) &ipi, 1528 sizeof(ipi), IP_PKTINFO, IPPROTO_IP); 1529 if (*mp) 1530 mp = &(*mp)->m_next; 1531 } 1532 if (inpflags & INP_RECVIF) { 1533 struct sockaddr_dl sdl; 1534 1535 sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0, 1536 NULL, 0); 1537 *mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP); 1538 if (*mp) 1539 mp = &(*mp)->m_next; 1540 } 1541 if (inpflags & INP_RECVTTL) { 1542 *mp = sbcreatecontrol((void *) &ip->ip_ttl, 1543 sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP); 1544 if (*mp) 1545 mp = &(*mp)->m_next; 1546 } 1547 m_put_rcvif_psref(ifp, &psref); 1548} 1549 1550/* 1551 * sysctl helper routine for net.inet.ip.forwsrcrt. 1552 */ 1553static int 1554sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS) 1555{ 1556 int error, tmp; 1557 struct sysctlnode node; 1558 1559 node = *rnode; 1560 tmp = ip_forwsrcrt; 1561 node.sysctl_data = &tmp; 1562 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1563 if (error || newp == NULL) 1564 return (error); 1565 1566 error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT, 1567 0, NULL, NULL, NULL); 1568 if (error) 1569 return (error); 1570 1571 ip_forwsrcrt = tmp; 1572 1573 return (0); 1574} 1575 1576/* 1577 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the 1578 * range of the new value and tweaks timers if it changes. 1579 */ 1580static int 1581sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS) 1582{ 1583 int error, tmp; 1584 struct sysctlnode node; 1585 1586 node = *rnode; 1587 tmp = ip_mtudisc_timeout; 1588 node.sysctl_data = &tmp; 1589 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1590 if (error || newp == NULL) 1591 return (error); 1592 if (tmp < 0) 1593 return (EINVAL); 1594 1595 mutex_enter(softnet_lock); 1596 1597 ip_mtudisc_timeout = tmp; 1598 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout); 1599 1600 mutex_exit(softnet_lock); 1601 1602 return (0); 1603} 1604 1605static int 1606sysctl_net_inet_ip_stats(SYSCTLFN_ARGS) 1607{ 1608 1609 return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS)); 1610} 1611 1612static void 1613sysctl_net_inet_ip_setup(struct sysctllog **clog) 1614{ 1615 sysctl_createv(clog, 0, NULL, NULL, 1616 CTLFLAG_PERMANENT, 1617 CTLTYPE_NODE, "inet", 1618 SYSCTL_DESCR("PF_INET related settings"), 1619 NULL, 0, NULL, 0, 1620 CTL_NET, PF_INET, CTL_EOL); 1621 sysctl_createv(clog, 0, NULL, NULL, 1622 CTLFLAG_PERMANENT, 1623 CTLTYPE_NODE, "ip", 1624 SYSCTL_DESCR("IPv4 related settings"), 1625 NULL, 0, NULL, 0, 1626 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL); 1627 1628 sysctl_createv(clog, 0, NULL, NULL, 1629 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1630 CTLTYPE_INT, "forwarding", 1631 SYSCTL_DESCR("Enable forwarding of INET datagrams"), 1632 NULL, 0, &ipforwarding, 0, 1633 CTL_NET, PF_INET, IPPROTO_IP, 1634 IPCTL_FORWARDING, CTL_EOL); 1635 sysctl_createv(clog, 0, NULL, NULL, 1636 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1637 CTLTYPE_INT, "redirect", 1638 SYSCTL_DESCR("Enable sending of ICMP redirect messages"), 1639 NULL, 0, &ipsendredirects, 0, 1640 CTL_NET, PF_INET, IPPROTO_IP, 1641 IPCTL_SENDREDIRECTS, CTL_EOL); 1642 sysctl_createv(clog, 0, NULL, NULL, 1643 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1644 CTLTYPE_INT, "ttl", 1645 SYSCTL_DESCR("Default TTL for an INET datagram"), 1646 NULL, 0, &ip_defttl, 0, 1647 CTL_NET, PF_INET, IPPROTO_IP, 1648 IPCTL_DEFTTL, CTL_EOL); 1649#ifdef IPCTL_DEFMTU 1650 sysctl_createv(clog, 0, NULL, NULL, 1651 CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */, 1652 CTLTYPE_INT, "mtu", 1653 SYSCTL_DESCR("Default MTA for an INET route"), 1654 NULL, 0, &ip_mtu, 0, 1655 CTL_NET, PF_INET, IPPROTO_IP, 1656 IPCTL_DEFMTU, CTL_EOL); 1657#endif /* IPCTL_DEFMTU */ 1658 sysctl_createv(clog, 0, NULL, NULL, 1659 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1660 CTLTYPE_INT, "forwsrcrt", 1661 SYSCTL_DESCR("Enable forwarding of source-routed " 1662 "datagrams"), 1663 sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0, 1664 CTL_NET, PF_INET, IPPROTO_IP, 1665 IPCTL_FORWSRCRT, CTL_EOL); 1666 sysctl_createv(clog, 0, NULL, NULL, 1667 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1668 CTLTYPE_INT, "directed-broadcast", 1669 SYSCTL_DESCR("Enable forwarding of broadcast datagrams"), 1670 NULL, 0, &ip_directedbcast, 0, 1671 CTL_NET, PF_INET, IPPROTO_IP, 1672 IPCTL_DIRECTEDBCAST, CTL_EOL); 1673 sysctl_createv(clog, 0, NULL, NULL, 1674 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1675 CTLTYPE_INT, "allowsrcrt", 1676 SYSCTL_DESCR("Accept source-routed datagrams"), 1677 NULL, 0, &ip_allowsrcrt, 0, 1678 CTL_NET, PF_INET, IPPROTO_IP, 1679 IPCTL_ALLOWSRCRT, CTL_EOL); 1680 1681 sysctl_createv(clog, 0, NULL, NULL, 1682 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1683 CTLTYPE_INT, "mtudisc", 1684 SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"), 1685 NULL, 0, &ip_mtudisc, 0, 1686 CTL_NET, PF_INET, IPPROTO_IP, 1687 IPCTL_MTUDISC, CTL_EOL); 1688 sysctl_createv(clog, 0, NULL, NULL, 1689 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1690 CTLTYPE_INT, "anonportmin", 1691 SYSCTL_DESCR("Lowest ephemeral port number to assign"), 1692 sysctl_net_inet_ip_ports, 0, &anonportmin, 0, 1693 CTL_NET, PF_INET, IPPROTO_IP, 1694 IPCTL_ANONPORTMIN, CTL_EOL); 1695 sysctl_createv(clog, 0, NULL, NULL, 1696 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1697 CTLTYPE_INT, "anonportmax", 1698 SYSCTL_DESCR("Highest ephemeral port number to assign"), 1699 sysctl_net_inet_ip_ports, 0, &anonportmax, 0, 1700 CTL_NET, PF_INET, IPPROTO_IP, 1701 IPCTL_ANONPORTMAX, CTL_EOL); 1702 sysctl_createv(clog, 0, NULL, NULL, 1703 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1704 CTLTYPE_INT, "mtudisctimeout", 1705 SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"), 1706 sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0, 1707 CTL_NET, PF_INET, IPPROTO_IP, 1708 IPCTL_MTUDISCTIMEOUT, CTL_EOL); 1709#ifndef IPNOPRIVPORTS 1710 sysctl_createv(clog, 0, NULL, NULL, 1711 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1712 CTLTYPE_INT, "lowportmin", 1713 SYSCTL_DESCR("Lowest privileged ephemeral port number " 1714 "to assign"), 1715 sysctl_net_inet_ip_ports, 0, &lowportmin, 0, 1716 CTL_NET, PF_INET, IPPROTO_IP, 1717 IPCTL_LOWPORTMIN, CTL_EOL); 1718 sysctl_createv(clog, 0, NULL, NULL, 1719 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1720 CTLTYPE_INT, "lowportmax", 1721 SYSCTL_DESCR("Highest privileged ephemeral port number " 1722 "to assign"), 1723 sysctl_net_inet_ip_ports, 0, &lowportmax, 0, 1724 CTL_NET, PF_INET, IPPROTO_IP, 1725 IPCTL_LOWPORTMAX, CTL_EOL); 1726#endif /* IPNOPRIVPORTS */ 1727#if NGRE > 0 1728 sysctl_createv(clog, 0, NULL, NULL, 1729 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1730 CTLTYPE_INT, "grettl", 1731 SYSCTL_DESCR("Default TTL for a gre tunnel datagram"), 1732 NULL, 0, &ip_gre_ttl, 0, 1733 CTL_NET, PF_INET, IPPROTO_IP, 1734 IPCTL_GRE_TTL, CTL_EOL); 1735#endif /* NGRE */ 1736 sysctl_createv(clog, 0, NULL, NULL, 1737 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1738 CTLTYPE_INT, "checkinterface", 1739 SYSCTL_DESCR("Enable receive side of Strong ES model " 1740 "from RFC1122"), 1741 NULL, 0, &ip_checkinterface, 0, 1742 CTL_NET, PF_INET, IPPROTO_IP, 1743 IPCTL_CHECKINTERFACE, CTL_EOL); 1744 sysctl_createv(clog, 0, NULL, NULL, 1745 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1746 CTLTYPE_INT, "random_id", 1747 SYSCTL_DESCR("Assign random ip_id values"), 1748 NULL, 0, &ip_do_randomid, 0, 1749 CTL_NET, PF_INET, IPPROTO_IP, 1750 IPCTL_RANDOMID, CTL_EOL); 1751 sysctl_createv(clog, 0, NULL, NULL, 1752 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1753 CTLTYPE_INT, "do_loopback_cksum", 1754 SYSCTL_DESCR("Perform IP checksum on loopback"), 1755 NULL, 0, &ip_do_loopback_cksum, 0, 1756 CTL_NET, PF_INET, IPPROTO_IP, 1757 IPCTL_LOOPBACKCKSUM, CTL_EOL); 1758 sysctl_createv(clog, 0, NULL, NULL, 1759 CTLFLAG_PERMANENT, 1760 CTLTYPE_STRUCT, "stats", 1761 SYSCTL_DESCR("IP statistics"), 1762 sysctl_net_inet_ip_stats, 0, NULL, 0, 1763 CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS, 1764 CTL_EOL); 1765#if NARP 1766 sysctl_createv(clog, 0, NULL, NULL, 1767 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1768 CTLTYPE_INT, "dad_count", 1769 SYSCTL_DESCR("Number of Duplicate Address Detection " 1770 "probes to send"), 1771 NULL, 0, &ip_dad_count, 0, 1772 CTL_NET, PF_INET, IPPROTO_IP, 1773 IPCTL_DAD_COUNT, CTL_EOL); 1774#endif 1775 1776 /* anonportalgo RFC6056 subtree */ 1777 const struct sysctlnode *portalgo_node; 1778 sysctl_createv(clog, 0, NULL, &portalgo_node, 1779 CTLFLAG_PERMANENT, 1780 CTLTYPE_NODE, "anonportalgo", 1781 SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"), 1782 NULL, 0, NULL, 0, 1783 CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL); 1784 sysctl_createv(clog, 0, &portalgo_node, NULL, 1785 CTLFLAG_PERMANENT, 1786 CTLTYPE_STRING, "available", 1787 SYSCTL_DESCR("available algorithms"), 1788 sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN, 1789 CTL_CREATE, CTL_EOL); 1790 sysctl_createv(clog, 0, &portalgo_node, NULL, 1791 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1792 CTLTYPE_STRING, "selected", 1793 SYSCTL_DESCR("selected algorithm"), 1794 sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN, 1795 CTL_CREATE, CTL_EOL); 1796 sysctl_createv(clog, 0, &portalgo_node, NULL, 1797 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1798 CTLTYPE_STRUCT, "reserve", 1799 SYSCTL_DESCR("bitmap of reserved ports"), 1800 sysctl_portalgo_reserve4, 0, NULL, 0, 1801 CTL_CREATE, CTL_EOL); 1802} 1803 1804void 1805ip_statinc(u_int stat) 1806{ 1807 1808 KASSERT(stat < IP_NSTATS); 1809 IP_STATINC(stat); 1810} 1811