ip_input.c revision 1.345
1/* $NetBSD: ip_input.c,v 1.345 2016/12/08 05:16:33 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 1.345 2016/12/08 05:16:33 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#include "opt_net_mpsafe.h" 105#endif 106 107#include "arp.h" 108 109#include <sys/param.h> 110#include <sys/systm.h> 111#include <sys/cpu.h> 112#include <sys/mbuf.h> 113#include <sys/domain.h> 114#include <sys/protosw.h> 115#include <sys/socket.h> 116#include <sys/socketvar.h> 117#include <sys/errno.h> 118#include <sys/time.h> 119#include <sys/kernel.h> 120#include <sys/pool.h> 121#include <sys/sysctl.h> 122#include <sys/kauth.h> 123 124#include <net/if.h> 125#include <net/if_dl.h> 126#include <net/route.h> 127#include <net/pktqueue.h> 128#include <net/pfil.h> 129 130#include <netinet/in.h> 131#include <netinet/in_systm.h> 132#include <netinet/ip.h> 133#include <netinet/in_pcb.h> 134#include <netinet/in_proto.h> 135#include <netinet/in_var.h> 136#include <netinet/ip_var.h> 137#include <netinet/ip_private.h> 138#include <netinet/ip_icmp.h> 139/* just for gif_ttl */ 140#include <netinet/in_gif.h> 141#include "gif.h" 142#include <net/if_gre.h> 143#include "gre.h" 144 145#ifdef MROUTING 146#include <netinet/ip_mroute.h> 147#endif 148#include <netinet/portalgo.h> 149 150#ifdef IPSEC 151#include <netipsec/ipsec.h> 152#endif 153 154#ifndef IPFORWARDING 155#ifdef GATEWAY 156#define IPFORWARDING 1 /* forward IP packets not for us */ 157#else /* GATEWAY */ 158#define IPFORWARDING 0 /* don't forward IP packets not for us */ 159#endif /* GATEWAY */ 160#endif /* IPFORWARDING */ 161#ifndef IPSENDREDIRECTS 162#define IPSENDREDIRECTS 1 163#endif 164#ifndef IPFORWSRCRT 165#define IPFORWSRCRT 1 /* forward source-routed packets */ 166#endif 167#ifndef IPALLOWSRCRT 168#define IPALLOWSRCRT 1 /* allow source-routed packets */ 169#endif 170#ifndef IPMTUDISC 171#define IPMTUDISC 1 172#endif 173#ifndef IPMTUDISCTIMEOUT 174#define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */ 175#endif 176 177#ifdef COMPAT_50 178#include <compat/sys/time.h> 179#include <compat/sys/socket.h> 180#endif 181 182/* 183 * Note: DIRECTED_BROADCAST is handled this way so that previous 184 * configuration using this option will Just Work. 185 */ 186#ifndef IPDIRECTEDBCAST 187#ifdef DIRECTED_BROADCAST 188#define IPDIRECTEDBCAST 1 189#else 190#define IPDIRECTEDBCAST 0 191#endif /* DIRECTED_BROADCAST */ 192#endif /* IPDIRECTEDBCAST */ 193int ipforwarding = IPFORWARDING; 194int ipsendredirects = IPSENDREDIRECTS; 195int ip_defttl = IPDEFTTL; 196int ip_forwsrcrt = IPFORWSRCRT; 197int ip_directedbcast = IPDIRECTEDBCAST; 198int ip_allowsrcrt = IPALLOWSRCRT; 199int ip_mtudisc = IPMTUDISC; 200int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 201#ifdef DIAGNOSTIC 202int ipprintfs = 0; 203#endif 204 205int ip_do_randomid = 0; 206 207/* 208 * XXX - Setting ip_checkinterface mostly implements the receive side of 209 * the Strong ES model described in RFC 1122, but since the routing table 210 * and transmit implementation do not implement the Strong ES model, 211 * setting this to 1 results in an odd hybrid. 212 * 213 * XXX - ip_checkinterface currently must be disabled if you use ipnat 214 * to translate the destination address to another local interface. 215 * 216 * XXX - ip_checkinterface must be disabled if you add IP aliases 217 * to the loopback interface instead of the interface where the 218 * packets for those addresses are received. 219 */ 220static int ip_checkinterface __read_mostly = 0; 221 222struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 223 224pktqueue_t * ip_pktq __read_mostly; 225pfil_head_t * inet_pfil_hook __read_mostly; 226ipid_state_t * ip_ids __read_mostly; 227percpu_t * ipstat_percpu __read_mostly; 228 229static percpu_t *ipforward_rt_percpu __cacheline_aligned; 230 231uint16_t ip_id; 232 233#ifdef INET_CSUM_COUNTERS 234#include <sys/device.h> 235 236struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 237 NULL, "inet", "hwcsum bad"); 238struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 239 NULL, "inet", "hwcsum ok"); 240struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 241 NULL, "inet", "swcsum"); 242 243#define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 244 245EVCNT_ATTACH_STATIC(ip_hwcsum_bad); 246EVCNT_ATTACH_STATIC(ip_hwcsum_ok); 247EVCNT_ATTACH_STATIC(ip_swcsum); 248 249#else 250 251#define INET_CSUM_COUNTER_INCR(ev) /* nothing */ 252 253#endif /* INET_CSUM_COUNTERS */ 254 255/* 256 * We need to save the IP options in case a protocol wants to respond 257 * to an incoming packet over the same route if the packet got here 258 * using IP source routing. This allows connection establishment and 259 * maintenance when the remote end is on a network that is not known 260 * to us. 261 */ 262 263static int ip_nhops = 0; 264 265static struct ip_srcrt { 266 struct in_addr dst; /* final destination */ 267 char nop; /* one NOP to align */ 268 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 269 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 270} ip_srcrt; 271 272static int ip_drainwanted; 273 274struct sockaddr_in ipaddr = { 275 .sin_len = sizeof(ipaddr), 276 .sin_family = AF_INET, 277}; 278 279static void save_rte(u_char *, struct in_addr); 280 281#ifdef MBUFTRACE 282struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx"); 283struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx"); 284#endif 285 286static void ipintr(void *); 287static void ip_input(struct mbuf *); 288static void ip_forward(struct mbuf *, int, struct ifnet *); 289static bool ip_dooptions(struct mbuf *); 290static struct in_ifaddr *ip_rtaddr(struct in_addr); 291static void sysctl_net_inet_ip_setup(struct sysctllog **); 292 293static struct in_ifaddr *ip_match_our_address(struct ifnet *, struct ip *, 294 int *); 295static struct in_ifaddr *ip_match_our_address_broadcast(struct ifnet *, 296 struct ip *); 297 298#ifdef NET_MPSAFE 299#define SOFTNET_LOCK() mutex_enter(softnet_lock) 300#define SOFTNET_UNLOCK() mutex_exit(softnet_lock) 301#else 302#define SOFTNET_LOCK() KASSERT(mutex_owned(softnet_lock)) 303#define SOFTNET_UNLOCK() KASSERT(mutex_owned(softnet_lock)) 304#endif 305 306/* 307 * IP initialization: fill in IP protocol switch table. 308 * All protocols not implemented in kernel go to raw IP protocol handler. 309 */ 310void 311ip_init(void) 312{ 313 const struct protosw *pr; 314 315 in_init(); 316 sysctl_net_inet_ip_setup(NULL); 317 318 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 319 KASSERT(pr != NULL); 320 321 ip_pktq = pktq_create(IFQ_MAXLEN, ipintr, NULL); 322 KASSERT(ip_pktq != NULL); 323 324 for (u_int i = 0; i < IPPROTO_MAX; i++) { 325 ip_protox[i] = pr - inetsw; 326 } 327 for (pr = inetdomain.dom_protosw; 328 pr < inetdomain.dom_protoswNPROTOSW; pr++) 329 if (pr->pr_domain->dom_family == PF_INET && 330 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 331 ip_protox[pr->pr_protocol] = pr - inetsw; 332 333 ip_reass_init(); 334 335 ip_ids = ip_id_init(); 336 ip_id = time_uptime & 0xfffff; 337 338 ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout); 339#ifdef GATEWAY 340 ipflow_init(); 341#endif 342 343 /* Register our Packet Filter hook. */ 344 inet_pfil_hook = pfil_head_create(PFIL_TYPE_AF, (void *)AF_INET); 345 KASSERT(inet_pfil_hook != NULL); 346 347#ifdef MBUFTRACE 348 MOWNER_ATTACH(&ip_tx_mowner); 349 MOWNER_ATTACH(&ip_rx_mowner); 350#endif /* MBUFTRACE */ 351 352 ipstat_percpu = percpu_alloc(sizeof(uint64_t) * IP_NSTATS); 353 354 ipforward_rt_percpu = percpu_alloc(sizeof(struct route)); 355 if (ipforward_rt_percpu == NULL) 356 panic("failed to allocate ipforward_rt_percpu"); 357} 358 359static struct in_ifaddr * 360ip_match_our_address(struct ifnet *ifp, struct ip *ip, int *downmatch) 361{ 362 struct in_ifaddr *ia = NULL; 363 int checkif; 364 365 /* 366 * Enable a consistency check between the destination address 367 * and the arrival interface for a unicast packet (the RFC 1122 368 * strong ES model) if IP forwarding is disabled and the packet 369 * is not locally generated. 370 * 371 * XXX - Checking also should be disabled if the destination 372 * address is ipnat'ed to a different interface. 373 * 374 * XXX - Checking is incompatible with IP aliases added 375 * to the loopback interface instead of the interface where 376 * the packets are received. 377 * 378 * XXX - We need to add a per ifaddr flag for this so that 379 * we get finer grain control. 380 */ 381 checkif = ip_checkinterface && (ipforwarding == 0) && 382 (ifp->if_flags & IFF_LOOPBACK) == 0; 383 384 IN_ADDRHASH_READER_FOREACH(ia, ip->ip_dst.s_addr) { 385 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) { 386 if (ia->ia4_flags & IN_IFF_NOTREADY) 387 continue; 388 if (checkif && ia->ia_ifp != ifp) 389 continue; 390 if ((ia->ia_ifp->if_flags & IFF_UP) != 0 && 391 (ia->ia4_flags & IN_IFF_DETACHED) == 0) 392 break; 393 else 394 (*downmatch)++; 395 } 396 } 397 398 return ia; 399} 400 401static struct in_ifaddr * 402ip_match_our_address_broadcast(struct ifnet *ifp, struct ip *ip) 403{ 404 struct in_ifaddr *ia = NULL; 405 struct ifaddr *ifa; 406 407 IFADDR_READER_FOREACH(ifa, ifp) { 408 if (ifa->ifa_addr->sa_family != AF_INET) 409 continue; 410 ia = ifatoia(ifa); 411 if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED)) 412 continue; 413 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 414 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 415 /* 416 * Look for all-0's host part (old broadcast addr), 417 * either for subnet or net. 418 */ 419 ip->ip_dst.s_addr == ia->ia_subnet || 420 ip->ip_dst.s_addr == ia->ia_net) 421 goto matched; 422 /* 423 * An interface with IP address zero accepts 424 * all packets that arrive on that interface. 425 */ 426 if (in_nullhost(ia->ia_addr.sin_addr)) 427 goto matched; 428 } 429 ia = NULL; 430 431matched: 432 return ia; 433} 434 435/* 436 * IP software interrupt routine. 437 */ 438static void 439ipintr(void *arg __unused) 440{ 441 struct mbuf *m; 442 443 KASSERT(cpu_softintr_p()); 444 445#ifndef NET_MPSAFE 446 mutex_enter(softnet_lock); 447#endif 448 while ((m = pktq_dequeue(ip_pktq)) != NULL) { 449 ip_input(m); 450 } 451#ifndef NET_MPSAFE 452 mutex_exit(softnet_lock); 453#endif 454} 455 456/* 457 * IP input routine. Checksum and byte swap header. If fragmented 458 * try to reassemble. Process options. Pass to next level. 459 */ 460static void 461ip_input(struct mbuf *m) 462{ 463 struct ip *ip = NULL; 464 struct in_ifaddr *ia = NULL; 465 int hlen = 0, len; 466 int downmatch; 467 int srcrt = 0; 468 ifnet_t *ifp; 469 struct psref psref; 470 int s; 471 472 KASSERTMSG(cpu_softintr_p(), "ip_input: not in the software " 473 "interrupt handler; synchronization assumptions violated"); 474 475 MCLAIM(m, &ip_rx_mowner); 476 KASSERT((m->m_flags & M_PKTHDR) != 0); 477 478 ifp = m_get_rcvif_psref(m, &psref); 479 if (__predict_false(ifp == NULL)) 480 goto out; 481 482 /* 483 * If no IP addresses have been set yet but the interfaces 484 * are receiving, can't do anything with incoming packets yet. 485 * Note: we pre-check without locks held. 486 */ 487 if (IN_ADDRLIST_READER_EMPTY()) 488 goto out; 489 IP_STATINC(IP_STAT_TOTAL); 490 491 /* 492 * If the IP header is not aligned, slurp it up into a new 493 * mbuf with space for link headers, in the event we forward 494 * it. Otherwise, if it is aligned, make sure the entire 495 * base IP header is in the first mbuf of the chain. 496 */ 497 if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) { 498 if ((m = m_copyup(m, sizeof(struct ip), 499 (max_linkhdr + 3) & ~3)) == NULL) { 500 /* XXXJRT new stat, please */ 501 IP_STATINC(IP_STAT_TOOSMALL); 502 goto out; 503 } 504 } else if (__predict_false(m->m_len < sizeof (struct ip))) { 505 if ((m = m_pullup(m, sizeof (struct ip))) == NULL) { 506 IP_STATINC(IP_STAT_TOOSMALL); 507 goto out; 508 } 509 } 510 ip = mtod(m, struct ip *); 511 if (ip->ip_v != IPVERSION) { 512 IP_STATINC(IP_STAT_BADVERS); 513 goto out; 514 } 515 hlen = ip->ip_hl << 2; 516 if (hlen < sizeof(struct ip)) { /* minimum header length */ 517 IP_STATINC(IP_STAT_BADHLEN); 518 goto out; 519 } 520 if (hlen > m->m_len) { 521 if ((m = m_pullup(m, hlen)) == NULL) { 522 IP_STATINC(IP_STAT_BADHLEN); 523 goto out; 524 } 525 ip = mtod(m, struct ip *); 526 } 527 528 /* 529 * RFC1122: packets with a multicast source address are 530 * not allowed. 531 */ 532 if (IN_MULTICAST(ip->ip_src.s_addr)) { 533 IP_STATINC(IP_STAT_BADADDR); 534 goto out; 535 } 536 537 /* 127/8 must not appear on wire - RFC1122 */ 538 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 539 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 540 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 541 IP_STATINC(IP_STAT_BADADDR); 542 goto out; 543 } 544 } 545 546 switch (m->m_pkthdr.csum_flags & 547 ((ifp->if_csum_flags_rx & M_CSUM_IPv4) | 548 M_CSUM_IPv4_BAD)) { 549 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 550 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad); 551 IP_STATINC(IP_STAT_BADSUM); 552 goto out; 553 554 case M_CSUM_IPv4: 555 /* Checksum was okay. */ 556 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok); 557 break; 558 559 default: 560 /* 561 * Must compute it ourselves. Maybe skip checksum on 562 * loopback interfaces. 563 */ 564 if (__predict_true(!(ifp->if_flags & IFF_LOOPBACK) || 565 ip_do_loopback_cksum)) { 566 INET_CSUM_COUNTER_INCR(&ip_swcsum); 567 if (in_cksum(m, hlen) != 0) { 568 IP_STATINC(IP_STAT_BADSUM); 569 goto out; 570 } 571 } 572 break; 573 } 574 575 /* Retrieve the packet length. */ 576 len = ntohs(ip->ip_len); 577 578 /* 579 * Check for additional length bogosity 580 */ 581 if (len < hlen) { 582 IP_STATINC(IP_STAT_BADLEN); 583 goto out; 584 } 585 586 /* 587 * Check that the amount of data in the buffers 588 * is as at least much as the IP header would have us expect. 589 * Trim mbufs if longer than we expect. 590 * Drop packet if shorter than we expect. 591 */ 592 if (m->m_pkthdr.len < len) { 593 IP_STATINC(IP_STAT_TOOSHORT); 594 goto out; 595 } 596 if (m->m_pkthdr.len > len) { 597 if (m->m_len == m->m_pkthdr.len) { 598 m->m_len = len; 599 m->m_pkthdr.len = len; 600 } else 601 m_adj(m, len - m->m_pkthdr.len); 602 } 603 604 /* 605 * Assume that we can create a fast-forward IP flow entry 606 * based on this packet. 607 */ 608 m->m_flags |= M_CANFASTFWD; 609 610 /* 611 * Run through list of hooks for input packets. If there are any 612 * filters which require that additional packets in the flow are 613 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 614 * Note that filters must _never_ set this flag, as another filter 615 * in the list may have previously cleared it. 616 */ 617#if defined(IPSEC) 618 if (!ipsec_used || !ipsec_indone(m)) 619#else 620 if (1) 621#endif 622 { 623 struct in_addr odst = ip->ip_dst; 624 bool freed; 625 626 freed = pfil_run_hooks(inet_pfil_hook, &m, ifp, PFIL_IN) != 0; 627 if (freed || m == NULL) { 628 m = NULL; 629 goto out; 630 } 631 ip = mtod(m, struct ip *); 632 hlen = ip->ip_hl << 2; 633 634 /* 635 * XXX The setting of "srcrt" here is to prevent ip_forward() 636 * from generating ICMP redirects for packets that have 637 * been redirected by a hook back out on to the same LAN that 638 * they came from and is not an indication that the packet 639 * is being inffluenced by source routing options. This 640 * allows things like 641 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp" 642 * where tlp0 is both on the 1.1.1.0/24 network and is the 643 * default route for hosts on 1.1.1.0/24. Of course this 644 * also requires a "map tlp0 ..." to complete the story. 645 * One might argue whether or not this kind of network config. 646 * should be supported in this manner... 647 */ 648 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 649 } 650 651#ifdef ALTQ 652 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 653 if (altq_input) { 654 SOFTNET_LOCK(); 655 if ((*altq_input)(m, AF_INET) == 0) { 656 /* Packet dropped by traffic conditioner. */ 657 SOFTNET_UNLOCK(); 658 m = NULL; 659 goto out; 660 } 661 SOFTNET_UNLOCK(); 662 } 663#endif 664 665 /* 666 * Process options and, if not destined for us, 667 * ship it on. ip_dooptions returns 1 when an 668 * error was detected (causing an icmp message 669 * to be sent and the original packet to be freed). 670 */ 671 ip_nhops = 0; /* for source routed packets */ 672 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 673 m = NULL; 674 goto out; 675 } 676 677 /* 678 * Check our list of addresses, to see if the packet is for us. 679 * 680 * Traditional 4.4BSD did not consult IFF_UP at all. 681 * The behavior here is to treat addresses on !IFF_UP interface 682 * or IN_IFF_NOTREADY addresses as not mine. 683 */ 684 downmatch = 0; 685 s = pserialize_read_enter(); 686 ia = ip_match_our_address(ifp, ip, &downmatch); 687 if (ia != NULL) { 688 pserialize_read_exit(s); 689 goto ours; 690 } 691 692 if (ifp->if_flags & IFF_BROADCAST) { 693 ia = ip_match_our_address_broadcast(ifp, ip); 694 if (ia != NULL) { 695 pserialize_read_exit(s); 696 goto ours; 697 } 698 } 699 pserialize_read_exit(s); 700 701 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 702#ifdef MROUTING 703 extern struct socket *ip_mrouter; 704 705 if (ip_mrouter) { 706 /* 707 * If we are acting as a multicast router, all 708 * incoming multicast packets are passed to the 709 * kernel-level multicast forwarding function. 710 * The packet is returned (relatively) intact; if 711 * ip_mforward() returns a non-zero value, the packet 712 * must be discarded, else it may be accepted below. 713 * 714 * (The IP ident field is put in the same byte order 715 * as expected when ip_mforward() is called from 716 * ip_output().) 717 */ 718 SOFTNET_LOCK(); 719 if (ip_mforward(m, ifp) != 0) { 720 SOFTNET_UNLOCK(); 721 IP_STATINC(IP_STAT_CANTFORWARD); 722 goto out; 723 } 724 SOFTNET_UNLOCK(); 725 726 /* 727 * The process-level routing demon needs to receive 728 * all multicast IGMP packets, whether or not this 729 * host belongs to their destination groups. 730 */ 731 if (ip->ip_p == IPPROTO_IGMP) { 732 goto ours; 733 } 734 IP_STATINC(IP_STAT_CANTFORWARD); 735 } 736#endif 737 /* 738 * See if we belong to the destination multicast group on the 739 * arrival interface. 740 */ 741 if (!in_multi_group(ip->ip_dst, ifp, 0)) { 742 IP_STATINC(IP_STAT_CANTFORWARD); 743 goto out; 744 } 745 goto ours; 746 } 747 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 748 in_nullhost(ip->ip_dst)) 749 goto ours; 750 751 /* 752 * Not for us; forward if possible and desirable. 753 */ 754 if (ipforwarding == 0) { 755 m_put_rcvif_psref(ifp, &psref); 756 IP_STATINC(IP_STAT_CANTFORWARD); 757 m_freem(m); 758 } else { 759 /* 760 * If ip_dst matched any of my address on !IFF_UP interface, 761 * and there's no IFF_UP interface that matches ip_dst, 762 * send icmp unreach. Forwarding it will result in in-kernel 763 * forwarding loop till TTL goes to 0. 764 */ 765 if (downmatch) { 766 m_put_rcvif_psref(ifp, &psref); 767 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 768 IP_STATINC(IP_STAT_CANTFORWARD); 769 return; 770 } 771#ifdef IPSEC 772 /* Perform IPsec, if any. */ 773 if (ipsec_used) { 774 SOFTNET_LOCK(); 775 if (ipsec4_input(m, IP_FORWARDING | 776 (ip_directedbcast ? IP_ALLOWBROADCAST : 0)) != 0) { 777 SOFTNET_UNLOCK(); 778 goto out; 779 } 780 SOFTNET_UNLOCK(); 781 } 782#endif 783 ip_forward(m, srcrt, ifp); 784 m_put_rcvif_psref(ifp, &psref); 785 } 786 return; 787 788ours: 789 m_put_rcvif_psref(ifp, &psref); 790 ifp = NULL; 791 792 /* 793 * If offset or IP_MF are set, must reassemble. 794 */ 795 if (ip->ip_off & ~htons(IP_DF|IP_RF)) { 796 /* 797 * Pass to IP reassembly mechanism. 798 */ 799 if (ip_reass_packet(&m, ip) != 0) { 800 /* Failed; invalid fragment(s) or packet. */ 801 goto out; 802 } 803 if (m == NULL) { 804 /* More fragments should come; silently return. */ 805 goto out; 806 } 807 /* 808 * Reassembly is done, we have the final packet. 809 * Updated cached data in local variable(s). 810 */ 811 ip = mtod(m, struct ip *); 812 hlen = ip->ip_hl << 2; 813 } 814 815#ifdef IPSEC 816 /* 817 * Enforce IPsec policy checking if we are seeing last header. 818 * Note that we do not visit this with protocols with PCB layer 819 * code - like UDP/TCP/raw IP. 820 */ 821 if (ipsec_used && 822 (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 823 SOFTNET_LOCK(); 824 if (ipsec4_input(m, 0) != 0) { 825 SOFTNET_UNLOCK(); 826 goto out; 827 } 828 SOFTNET_UNLOCK(); 829 } 830#endif 831 832 /* 833 * Switch out to protocol's input routine. 834 */ 835#if IFA_STATS 836 if (ia && ip) { 837 struct in_ifaddr *_ia; 838 /* 839 * Keep a reference from ip_match_our_address with psref 840 * is expensive, so explore ia here again. 841 */ 842 s = pserialize_read_enter(); 843 _ia = in_get_ia(ip->ip_dst); 844 _ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len); 845 pserialize_read_exit(s); 846 } 847#endif 848 IP_STATINC(IP_STAT_DELIVERED); 849 850 const int off = hlen, nh = ip->ip_p; 851 852 SOFTNET_LOCK(); 853 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 854 SOFTNET_UNLOCK(); 855 return; 856 857out: 858 m_put_rcvif_psref(ifp, &psref); 859 if (m != NULL) 860 m_freem(m); 861} 862 863/* 864 * IP timer processing. 865 */ 866void 867ip_slowtimo(void) 868{ 869 870 mutex_enter(softnet_lock); 871 KERNEL_LOCK(1, NULL); 872 873 ip_reass_slowtimo(); 874 875 KERNEL_UNLOCK_ONE(NULL); 876 mutex_exit(softnet_lock); 877} 878 879/* 880 * IP drain processing. 881 */ 882void 883ip_drain(void) 884{ 885 886 KERNEL_LOCK(1, NULL); 887 ip_reass_drain(); 888 KERNEL_UNLOCK_ONE(NULL); 889} 890 891/* 892 * ip_dooptions: perform option processing on a datagram, possibly discarding 893 * it if bad options are encountered, or forwarding it if source-routed. 894 * 895 * => Returns true if packet has been forwarded/freed. 896 * => Returns false if the packet should be processed further. 897 */ 898static bool 899ip_dooptions(struct mbuf *m) 900{ 901 struct ip *ip = mtod(m, struct ip *); 902 u_char *cp, *cp0; 903 struct ip_timestamp *ipt; 904 struct in_ifaddr *ia; 905 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 906 struct in_addr dst; 907 n_time ntime; 908 struct ifaddr *ifa; 909 int s; 910 911 dst = ip->ip_dst; 912 cp = (u_char *)(ip + 1); 913 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 914 for (; cnt > 0; cnt -= optlen, cp += optlen) { 915 opt = cp[IPOPT_OPTVAL]; 916 if (opt == IPOPT_EOL) 917 break; 918 if (opt == IPOPT_NOP) 919 optlen = 1; 920 else { 921 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 922 code = &cp[IPOPT_OLEN] - (u_char *)ip; 923 goto bad; 924 } 925 optlen = cp[IPOPT_OLEN]; 926 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 927 code = &cp[IPOPT_OLEN] - (u_char *)ip; 928 goto bad; 929 } 930 } 931 switch (opt) { 932 933 default: 934 break; 935 936 /* 937 * Source routing with record. 938 * Find interface with current destination address. 939 * If none on this machine then drop if strictly routed, 940 * or do nothing if loosely routed. 941 * Record interface address and bring up next address 942 * component. If strictly routed make sure next 943 * address is on directly accessible net. 944 */ 945 case IPOPT_LSRR: 946 case IPOPT_SSRR: 947 if (ip_allowsrcrt == 0) { 948 type = ICMP_UNREACH; 949 code = ICMP_UNREACH_NET_PROHIB; 950 goto bad; 951 } 952 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 953 code = &cp[IPOPT_OLEN] - (u_char *)ip; 954 goto bad; 955 } 956 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 957 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 958 goto bad; 959 } 960 ipaddr.sin_addr = ip->ip_dst; 961 962 s = pserialize_read_enter(); 963 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 964 if (ifa == NULL) { 965 pserialize_read_exit(s); 966 if (opt == IPOPT_SSRR) { 967 type = ICMP_UNREACH; 968 code = ICMP_UNREACH_SRCFAIL; 969 goto bad; 970 } 971 /* 972 * Loose routing, and not at next destination 973 * yet; nothing to do except forward. 974 */ 975 break; 976 } 977 pserialize_read_exit(s); 978 979 off--; /* 0 origin */ 980 if ((off + sizeof(struct in_addr)) > optlen) { 981 /* 982 * End of source route. Should be for us. 983 */ 984 save_rte(cp, ip->ip_src); 985 break; 986 } 987 /* 988 * locate outgoing interface 989 */ 990 memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off), 991 sizeof(ipaddr.sin_addr)); 992 s = pserialize_read_enter(); 993 if (opt == IPOPT_SSRR) { 994 ifa = ifa_ifwithladdr(sintosa(&ipaddr)); 995 if (ifa != NULL) 996 ia = ifatoia(ifa); 997 else 998 ia = NULL; 999 } else { 1000 ia = ip_rtaddr(ipaddr.sin_addr); 1001 } 1002 if (ia == NULL) { 1003 type = ICMP_UNREACH; 1004 code = ICMP_UNREACH_SRCFAIL; 1005 pserialize_read_exit(s); 1006 goto bad; 1007 } 1008 ip->ip_dst = ipaddr.sin_addr; 1009 bcopy((void *)&ia->ia_addr.sin_addr, 1010 (void *)(cp + off), sizeof(struct in_addr)); 1011 pserialize_read_exit(s); 1012 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1013 /* 1014 * Let ip_intr's mcast routing check handle mcast pkts 1015 */ 1016 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1017 break; 1018 1019 case IPOPT_RR: 1020 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1021 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1022 goto bad; 1023 } 1024 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1025 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1026 goto bad; 1027 } 1028 /* 1029 * If no space remains, ignore. 1030 */ 1031 off--; /* 0 origin */ 1032 if ((off + sizeof(struct in_addr)) > optlen) 1033 break; 1034 memcpy((void *)&ipaddr.sin_addr, (void *)(&ip->ip_dst), 1035 sizeof(ipaddr.sin_addr)); 1036 /* 1037 * locate outgoing interface; if we're the destination, 1038 * use the incoming interface (should be same). 1039 */ 1040 s = pserialize_read_enter(); 1041 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 1042 if (ifa == NULL) { 1043 ia = ip_rtaddr(ipaddr.sin_addr); 1044 if (ia == NULL) { 1045 pserialize_read_exit(s); 1046 type = ICMP_UNREACH; 1047 code = ICMP_UNREACH_HOST; 1048 goto bad; 1049 } 1050 } else { 1051 ia = ifatoia(ifa); 1052 } 1053 bcopy((void *)&ia->ia_addr.sin_addr, 1054 (void *)(cp + off), sizeof(struct in_addr)); 1055 pserialize_read_exit(s); 1056 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1057 break; 1058 1059 case IPOPT_TS: 1060 code = cp - (u_char *)ip; 1061 ipt = (struct ip_timestamp *)cp; 1062 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1063 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1064 goto bad; 1065 } 1066 if (ipt->ipt_ptr < 5) { 1067 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1068 goto bad; 1069 } 1070 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) { 1071 if (++ipt->ipt_oflw == 0) { 1072 code = (u_char *)&ipt->ipt_ptr - 1073 (u_char *)ip; 1074 goto bad; 1075 } 1076 break; 1077 } 1078 cp0 = (cp + ipt->ipt_ptr - 1); 1079 switch (ipt->ipt_flg) { 1080 1081 case IPOPT_TS_TSONLY: 1082 break; 1083 1084 case IPOPT_TS_TSANDADDR: { 1085 struct ifnet *rcvif; 1086 int _s, _ss; 1087 1088 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1089 sizeof(struct in_addr) > ipt->ipt_len) { 1090 code = (u_char *)&ipt->ipt_ptr - 1091 (u_char *)ip; 1092 goto bad; 1093 } 1094 ipaddr.sin_addr = dst; 1095 _ss = pserialize_read_enter(); 1096 rcvif = m_get_rcvif(m, &_s); 1097 ifa = ifaof_ifpforaddr(sintosa(&ipaddr), rcvif); 1098 m_put_rcvif(rcvif, &_s); 1099 if (ifa == NULL) { 1100 pserialize_read_exit(_ss); 1101 break; 1102 } 1103 ia = ifatoia(ifa); 1104 bcopy(&ia->ia_addr.sin_addr, 1105 cp0, sizeof(struct in_addr)); 1106 pserialize_read_exit(_ss); 1107 ipt->ipt_ptr += sizeof(struct in_addr); 1108 break; 1109 } 1110 1111 case IPOPT_TS_PRESPEC: 1112 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1113 sizeof(struct in_addr) > ipt->ipt_len) { 1114 code = (u_char *)&ipt->ipt_ptr - 1115 (u_char *)ip; 1116 goto bad; 1117 } 1118 memcpy(&ipaddr.sin_addr, cp0, 1119 sizeof(struct in_addr)); 1120 s = pserialize_read_enter(); 1121 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 1122 if (ifa == NULL) { 1123 pserialize_read_exit(s); 1124 continue; 1125 } 1126 pserialize_read_exit(s); 1127 ipt->ipt_ptr += sizeof(struct in_addr); 1128 break; 1129 1130 default: 1131 /* XXX can't take &ipt->ipt_flg */ 1132 code = (u_char *)&ipt->ipt_ptr - 1133 (u_char *)ip + 1; 1134 goto bad; 1135 } 1136 ntime = iptime(); 1137 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1138 memmove((char *)cp + ipt->ipt_ptr - 1, cp0, 1139 sizeof(n_time)); 1140 ipt->ipt_ptr += sizeof(n_time); 1141 } 1142 } 1143 if (forward) { 1144 struct ifnet *rcvif; 1145 struct psref _psref; 1146 1147 if (ip_forwsrcrt == 0) { 1148 type = ICMP_UNREACH; 1149 code = ICMP_UNREACH_SRCFAIL; 1150 goto bad; 1151 } 1152 1153 rcvif = m_get_rcvif_psref(m, &_psref); 1154 if (__predict_false(rcvif == NULL)) { 1155 type = ICMP_UNREACH; 1156 code = ICMP_UNREACH_HOST; 1157 goto bad; 1158 } 1159 ip_forward(m, 1, rcvif); 1160 m_put_rcvif_psref(rcvif, &_psref); 1161 return true; 1162 } 1163 return false; 1164bad: 1165 icmp_error(m, type, code, 0, 0); 1166 IP_STATINC(IP_STAT_BADOPTIONS); 1167 return true; 1168} 1169 1170/* 1171 * ip_rtaddr: given address of next destination (final or next hop), 1172 * return internet address info of interface to be used to get there. 1173 */ 1174static struct in_ifaddr * 1175ip_rtaddr(struct in_addr dst) 1176{ 1177 struct rtentry *rt; 1178 union { 1179 struct sockaddr dst; 1180 struct sockaddr_in dst4; 1181 } u; 1182 struct route *ro; 1183 1184 sockaddr_in_init(&u.dst4, &dst, 0); 1185 1186 ro = percpu_getref(ipforward_rt_percpu); 1187 rt = rtcache_lookup(ro, &u.dst); 1188 if (rt == NULL) { 1189 percpu_putref(ipforward_rt_percpu); 1190 return NULL; 1191 } 1192 1193 rtcache_unref(rt, ro); 1194 percpu_putref(ipforward_rt_percpu); 1195 1196 return ifatoia(rt->rt_ifa); 1197} 1198 1199/* 1200 * save_rte: save incoming source route for use in replies, to be picked 1201 * up later by ip_srcroute if the receiver is interested. 1202 */ 1203static void 1204save_rte(u_char *option, struct in_addr dst) 1205{ 1206 unsigned olen; 1207 1208 olen = option[IPOPT_OLEN]; 1209 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1210 return; 1211 memcpy((void *)ip_srcrt.srcopt, (void *)option, olen); 1212 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1213 ip_srcrt.dst = dst; 1214} 1215 1216/* 1217 * Retrieve incoming source route for use in replies, 1218 * in the same form used by setsockopt. 1219 * The first hop is placed before the options, will be removed later. 1220 */ 1221struct mbuf * 1222ip_srcroute(void) 1223{ 1224 struct in_addr *p, *q; 1225 struct mbuf *m; 1226 1227 if (ip_nhops == 0) 1228 return NULL; 1229 m = m_get(M_DONTWAIT, MT_SOOPTS); 1230 if (m == 0) 1231 return NULL; 1232 1233 MCLAIM(m, &inetdomain.dom_mowner); 1234#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1235 1236 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1237 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1238 OPTSIZ; 1239 1240 /* 1241 * First save first hop for return route 1242 */ 1243 p = &ip_srcrt.route[ip_nhops - 1]; 1244 *(mtod(m, struct in_addr *)) = *p--; 1245 1246 /* 1247 * Copy option fields and padding (nop) to mbuf. 1248 */ 1249 ip_srcrt.nop = IPOPT_NOP; 1250 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1251 memmove(mtod(m, char *) + sizeof(struct in_addr), &ip_srcrt.nop, 1252 OPTSIZ); 1253 q = (struct in_addr *)(mtod(m, char *) + 1254 sizeof(struct in_addr) + OPTSIZ); 1255#undef OPTSIZ 1256 /* 1257 * Record return path as an IP source route, 1258 * reversing the path (pointers are now aligned). 1259 */ 1260 while (p >= ip_srcrt.route) { 1261 *q++ = *p--; 1262 } 1263 /* 1264 * Last hop goes to final destination. 1265 */ 1266 *q = ip_srcrt.dst; 1267 return (m); 1268} 1269 1270const int inetctlerrmap[PRC_NCMDS] = { 1271 [PRC_MSGSIZE] = EMSGSIZE, 1272 [PRC_HOSTDEAD] = EHOSTDOWN, 1273 [PRC_HOSTUNREACH] = EHOSTUNREACH, 1274 [PRC_UNREACH_NET] = EHOSTUNREACH, 1275 [PRC_UNREACH_HOST] = EHOSTUNREACH, 1276 [PRC_UNREACH_PROTOCOL] = ECONNREFUSED, 1277 [PRC_UNREACH_PORT] = ECONNREFUSED, 1278 [PRC_UNREACH_SRCFAIL] = EHOSTUNREACH, 1279 [PRC_PARAMPROB] = ENOPROTOOPT, 1280}; 1281 1282void 1283ip_fasttimo(void) 1284{ 1285 if (ip_drainwanted) { 1286 ip_drain(); 1287 ip_drainwanted = 0; 1288 } 1289} 1290 1291void 1292ip_drainstub(void) 1293{ 1294 ip_drainwanted = 1; 1295} 1296 1297/* 1298 * Forward a packet. If some error occurs return the sender 1299 * an icmp packet. Note we can't always generate a meaningful 1300 * icmp message because icmp doesn't have a large enough repertoire 1301 * of codes and types. 1302 * 1303 * If not forwarding, just drop the packet. This could be confusing 1304 * if ipforwarding was zero but some routing protocol was advancing 1305 * us as a gateway to somewhere. However, we must let the routing 1306 * protocol deal with that. 1307 * 1308 * The srcrt parameter indicates whether the packet is being forwarded 1309 * via a source route. 1310 */ 1311static void 1312ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif) 1313{ 1314 struct ip *ip = mtod(m, struct ip *); 1315 struct rtentry *rt; 1316 int error, type = 0, code = 0, destmtu = 0; 1317 struct mbuf *mcopy; 1318 n_long dest; 1319 union { 1320 struct sockaddr dst; 1321 struct sockaddr_in dst4; 1322 } u; 1323 uint64_t *ips; 1324 struct route *ro; 1325 1326 KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software " 1327 "interrupt handler; synchronization assumptions violated"); 1328 1329 /* 1330 * We are now in the output path. 1331 */ 1332 MCLAIM(m, &ip_tx_mowner); 1333 1334 /* 1335 * Clear any in-bound checksum flags for this packet. 1336 */ 1337 m->m_pkthdr.csum_flags = 0; 1338 1339 dest = 0; 1340 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1341 IP_STATINC(IP_STAT_CANTFORWARD); 1342 m_freem(m); 1343 return; 1344 } 1345 1346 if (ip->ip_ttl <= IPTTLDEC) { 1347 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1348 return; 1349 } 1350 1351 sockaddr_in_init(&u.dst4, &ip->ip_dst, 0); 1352 1353 ro = percpu_getref(ipforward_rt_percpu); 1354 rt = rtcache_lookup(ro, &u.dst); 1355 if (rt == NULL) { 1356 percpu_putref(ipforward_rt_percpu); 1357 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0); 1358 return; 1359 } 1360 1361 /* 1362 * Save at most 68 bytes of the packet in case 1363 * we need to generate an ICMP message to the src. 1364 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1365 */ 1366 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1367 if (mcopy) 1368 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1369 1370 ip->ip_ttl -= IPTTLDEC; 1371 1372 /* 1373 * If forwarding packet using same interface that it came in on, 1374 * perhaps should send a redirect to sender to shortcut a hop. 1375 * Only send redirect if source is sending directly to us, 1376 * and if packet was not source routed (or has any options). 1377 * Also, don't send redirect if forwarding using a default route 1378 * or a route modified by a redirect. 1379 */ 1380 if (rt->rt_ifp == rcvif && 1381 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1382 !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) && 1383 ipsendredirects && !srcrt) { 1384 if (rt->rt_ifa && 1385 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1386 ifatoia(rt->rt_ifa)->ia_subnet) { 1387 if (rt->rt_flags & RTF_GATEWAY) 1388 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1389 else 1390 dest = ip->ip_dst.s_addr; 1391 /* 1392 * Router requirements says to only send host 1393 * redirects. 1394 */ 1395 type = ICMP_REDIRECT; 1396 code = ICMP_REDIRECT_HOST; 1397 } 1398 } 1399 rtcache_unref(rt, ro); 1400 1401 error = ip_output(m, NULL, ro, 1402 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1403 NULL, NULL); 1404 1405 if (error) { 1406 IP_STATINC(IP_STAT_CANTFORWARD); 1407 goto error; 1408 } 1409 1410 ips = IP_STAT_GETREF(); 1411 ips[IP_STAT_FORWARD]++; 1412 1413 if (type) { 1414 ips[IP_STAT_REDIRECTSENT]++; 1415 IP_STAT_PUTREF(); 1416 goto redirect; 1417 } 1418 1419 IP_STAT_PUTREF(); 1420 if (mcopy) { 1421#ifdef GATEWAY 1422 if (mcopy->m_flags & M_CANFASTFWD) 1423 ipflow_create(ro, mcopy); 1424#endif 1425 m_freem(mcopy); 1426 } 1427 1428 percpu_putref(ipforward_rt_percpu); 1429 return; 1430 1431redirect: 1432error: 1433 if (mcopy == NULL) { 1434 percpu_putref(ipforward_rt_percpu); 1435 return; 1436 } 1437 1438 switch (error) { 1439 1440 case 0: /* forwarded, but need redirect */ 1441 /* type, code set above */ 1442 break; 1443 1444 case ENETUNREACH: /* shouldn't happen, checked above */ 1445 case EHOSTUNREACH: 1446 case ENETDOWN: 1447 case EHOSTDOWN: 1448 default: 1449 type = ICMP_UNREACH; 1450 code = ICMP_UNREACH_HOST; 1451 break; 1452 1453 case EMSGSIZE: 1454 type = ICMP_UNREACH; 1455 code = ICMP_UNREACH_NEEDFRAG; 1456 1457 if ((rt = rtcache_validate(ro)) != NULL) { 1458 destmtu = rt->rt_ifp->if_mtu; 1459 rtcache_unref(rt, ro); 1460 } 1461#ifdef IPSEC 1462 if (ipsec_used) 1463 (void)ipsec4_forward(mcopy, &destmtu); 1464#endif 1465 IP_STATINC(IP_STAT_CANTFRAG); 1466 break; 1467 1468 case ENOBUFS: 1469 /* 1470 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812, 1471 * Requirements for IP Version 4 Routers. Source quench can 1472 * big problem under DoS attacks or if the underlying 1473 * interface is rate-limited. 1474 */ 1475 if (mcopy) 1476 m_freem(mcopy); 1477 percpu_putref(ipforward_rt_percpu); 1478 return; 1479 } 1480 icmp_error(mcopy, type, code, dest, destmtu); 1481 percpu_putref(ipforward_rt_percpu); 1482} 1483 1484void 1485ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1486 struct mbuf *m) 1487{ 1488 struct socket *so = inp->inp_socket; 1489 ifnet_t *ifp; 1490 int inpflags = inp->inp_flags; 1491 struct psref psref; 1492 1493 ifp = m_get_rcvif_psref(m, &psref); 1494 if (__predict_false(ifp == NULL)) 1495 return; /* XXX should report error? */ 1496 1497 if (so->so_options & SO_TIMESTAMP 1498#ifdef SO_OTIMESTAMP 1499 || so->so_options & SO_OTIMESTAMP 1500#endif 1501 ) { 1502 struct timeval tv; 1503 1504 microtime(&tv); 1505#ifdef SO_OTIMESTAMP 1506 if (so->so_options & SO_OTIMESTAMP) { 1507 struct timeval50 tv50; 1508 timeval_to_timeval50(&tv, &tv50); 1509 *mp = sbcreatecontrol((void *) &tv50, sizeof(tv50), 1510 SCM_OTIMESTAMP, SOL_SOCKET); 1511 } else 1512#endif 1513 *mp = sbcreatecontrol((void *) &tv, sizeof(tv), 1514 SCM_TIMESTAMP, SOL_SOCKET); 1515 if (*mp) 1516 mp = &(*mp)->m_next; 1517 } 1518 if (inpflags & INP_RECVDSTADDR) { 1519 *mp = sbcreatecontrol((void *) &ip->ip_dst, 1520 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1521 if (*mp) 1522 mp = &(*mp)->m_next; 1523 } 1524 if (inpflags & INP_RECVPKTINFO) { 1525 struct in_pktinfo ipi; 1526 ipi.ipi_addr = ip->ip_src; 1527 ipi.ipi_ifindex = ifp->if_index; 1528 *mp = sbcreatecontrol((void *) &ipi, 1529 sizeof(ipi), IP_RECVPKTINFO, IPPROTO_IP); 1530 if (*mp) 1531 mp = &(*mp)->m_next; 1532 } 1533 if (inpflags & INP_PKTINFO) { 1534 struct in_pktinfo ipi; 1535 ipi.ipi_addr = ip->ip_dst; 1536 ipi.ipi_ifindex = ifp->if_index; 1537 *mp = sbcreatecontrol((void *) &ipi, 1538 sizeof(ipi), IP_PKTINFO, IPPROTO_IP); 1539 if (*mp) 1540 mp = &(*mp)->m_next; 1541 } 1542 if (inpflags & INP_RECVIF) { 1543 struct sockaddr_dl sdl; 1544 1545 sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0, 1546 NULL, 0); 1547 *mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP); 1548 if (*mp) 1549 mp = &(*mp)->m_next; 1550 } 1551 if (inpflags & INP_RECVTTL) { 1552 *mp = sbcreatecontrol((void *) &ip->ip_ttl, 1553 sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP); 1554 if (*mp) 1555 mp = &(*mp)->m_next; 1556 } 1557 m_put_rcvif_psref(ifp, &psref); 1558} 1559 1560/* 1561 * sysctl helper routine for net.inet.ip.forwsrcrt. 1562 */ 1563static int 1564sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS) 1565{ 1566 int error, tmp; 1567 struct sysctlnode node; 1568 1569 node = *rnode; 1570 tmp = ip_forwsrcrt; 1571 node.sysctl_data = &tmp; 1572 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1573 if (error || newp == NULL) 1574 return (error); 1575 1576 error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT, 1577 0, NULL, NULL, NULL); 1578 if (error) 1579 return (error); 1580 1581 ip_forwsrcrt = tmp; 1582 1583 return (0); 1584} 1585 1586/* 1587 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the 1588 * range of the new value and tweaks timers if it changes. 1589 */ 1590static int 1591sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS) 1592{ 1593 int error, tmp; 1594 struct sysctlnode node; 1595 1596 node = *rnode; 1597 tmp = ip_mtudisc_timeout; 1598 node.sysctl_data = &tmp; 1599 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1600 if (error || newp == NULL) 1601 return (error); 1602 if (tmp < 0) 1603 return (EINVAL); 1604 1605 mutex_enter(softnet_lock); 1606 1607 ip_mtudisc_timeout = tmp; 1608 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout); 1609 1610 mutex_exit(softnet_lock); 1611 1612 return (0); 1613} 1614 1615static int 1616sysctl_net_inet_ip_stats(SYSCTLFN_ARGS) 1617{ 1618 1619 return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS)); 1620} 1621 1622static void 1623sysctl_net_inet_ip_setup(struct sysctllog **clog) 1624{ 1625 sysctl_createv(clog, 0, NULL, NULL, 1626 CTLFLAG_PERMANENT, 1627 CTLTYPE_NODE, "inet", 1628 SYSCTL_DESCR("PF_INET related settings"), 1629 NULL, 0, NULL, 0, 1630 CTL_NET, PF_INET, CTL_EOL); 1631 sysctl_createv(clog, 0, NULL, NULL, 1632 CTLFLAG_PERMANENT, 1633 CTLTYPE_NODE, "ip", 1634 SYSCTL_DESCR("IPv4 related settings"), 1635 NULL, 0, NULL, 0, 1636 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL); 1637 1638 sysctl_createv(clog, 0, NULL, NULL, 1639 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1640 CTLTYPE_INT, "forwarding", 1641 SYSCTL_DESCR("Enable forwarding of INET datagrams"), 1642 NULL, 0, &ipforwarding, 0, 1643 CTL_NET, PF_INET, IPPROTO_IP, 1644 IPCTL_FORWARDING, CTL_EOL); 1645 sysctl_createv(clog, 0, NULL, NULL, 1646 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1647 CTLTYPE_INT, "redirect", 1648 SYSCTL_DESCR("Enable sending of ICMP redirect messages"), 1649 NULL, 0, &ipsendredirects, 0, 1650 CTL_NET, PF_INET, IPPROTO_IP, 1651 IPCTL_SENDREDIRECTS, CTL_EOL); 1652 sysctl_createv(clog, 0, NULL, NULL, 1653 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1654 CTLTYPE_INT, "ttl", 1655 SYSCTL_DESCR("Default TTL for an INET datagram"), 1656 NULL, 0, &ip_defttl, 0, 1657 CTL_NET, PF_INET, IPPROTO_IP, 1658 IPCTL_DEFTTL, CTL_EOL); 1659#ifdef IPCTL_DEFMTU 1660 sysctl_createv(clog, 0, NULL, NULL, 1661 CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */, 1662 CTLTYPE_INT, "mtu", 1663 SYSCTL_DESCR("Default MTA for an INET route"), 1664 NULL, 0, &ip_mtu, 0, 1665 CTL_NET, PF_INET, IPPROTO_IP, 1666 IPCTL_DEFMTU, CTL_EOL); 1667#endif /* IPCTL_DEFMTU */ 1668 sysctl_createv(clog, 0, NULL, NULL, 1669 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1670 CTLTYPE_INT, "forwsrcrt", 1671 SYSCTL_DESCR("Enable forwarding of source-routed " 1672 "datagrams"), 1673 sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0, 1674 CTL_NET, PF_INET, IPPROTO_IP, 1675 IPCTL_FORWSRCRT, CTL_EOL); 1676 sysctl_createv(clog, 0, NULL, NULL, 1677 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1678 CTLTYPE_INT, "directed-broadcast", 1679 SYSCTL_DESCR("Enable forwarding of broadcast datagrams"), 1680 NULL, 0, &ip_directedbcast, 0, 1681 CTL_NET, PF_INET, IPPROTO_IP, 1682 IPCTL_DIRECTEDBCAST, CTL_EOL); 1683 sysctl_createv(clog, 0, NULL, NULL, 1684 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1685 CTLTYPE_INT, "allowsrcrt", 1686 SYSCTL_DESCR("Accept source-routed datagrams"), 1687 NULL, 0, &ip_allowsrcrt, 0, 1688 CTL_NET, PF_INET, IPPROTO_IP, 1689 IPCTL_ALLOWSRCRT, CTL_EOL); 1690 1691 sysctl_createv(clog, 0, NULL, NULL, 1692 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1693 CTLTYPE_INT, "mtudisc", 1694 SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"), 1695 NULL, 0, &ip_mtudisc, 0, 1696 CTL_NET, PF_INET, IPPROTO_IP, 1697 IPCTL_MTUDISC, CTL_EOL); 1698 sysctl_createv(clog, 0, NULL, NULL, 1699 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1700 CTLTYPE_INT, "anonportmin", 1701 SYSCTL_DESCR("Lowest ephemeral port number to assign"), 1702 sysctl_net_inet_ip_ports, 0, &anonportmin, 0, 1703 CTL_NET, PF_INET, IPPROTO_IP, 1704 IPCTL_ANONPORTMIN, CTL_EOL); 1705 sysctl_createv(clog, 0, NULL, NULL, 1706 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1707 CTLTYPE_INT, "anonportmax", 1708 SYSCTL_DESCR("Highest ephemeral port number to assign"), 1709 sysctl_net_inet_ip_ports, 0, &anonportmax, 0, 1710 CTL_NET, PF_INET, IPPROTO_IP, 1711 IPCTL_ANONPORTMAX, CTL_EOL); 1712 sysctl_createv(clog, 0, NULL, NULL, 1713 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1714 CTLTYPE_INT, "mtudisctimeout", 1715 SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"), 1716 sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0, 1717 CTL_NET, PF_INET, IPPROTO_IP, 1718 IPCTL_MTUDISCTIMEOUT, CTL_EOL); 1719#ifndef IPNOPRIVPORTS 1720 sysctl_createv(clog, 0, NULL, NULL, 1721 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1722 CTLTYPE_INT, "lowportmin", 1723 SYSCTL_DESCR("Lowest privileged ephemeral port number " 1724 "to assign"), 1725 sysctl_net_inet_ip_ports, 0, &lowportmin, 0, 1726 CTL_NET, PF_INET, IPPROTO_IP, 1727 IPCTL_LOWPORTMIN, CTL_EOL); 1728 sysctl_createv(clog, 0, NULL, NULL, 1729 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1730 CTLTYPE_INT, "lowportmax", 1731 SYSCTL_DESCR("Highest privileged ephemeral port number " 1732 "to assign"), 1733 sysctl_net_inet_ip_ports, 0, &lowportmax, 0, 1734 CTL_NET, PF_INET, IPPROTO_IP, 1735 IPCTL_LOWPORTMAX, CTL_EOL); 1736#endif /* IPNOPRIVPORTS */ 1737#if NGRE > 0 1738 sysctl_createv(clog, 0, NULL, NULL, 1739 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1740 CTLTYPE_INT, "grettl", 1741 SYSCTL_DESCR("Default TTL for a gre tunnel datagram"), 1742 NULL, 0, &ip_gre_ttl, 0, 1743 CTL_NET, PF_INET, IPPROTO_IP, 1744 IPCTL_GRE_TTL, CTL_EOL); 1745#endif /* NGRE */ 1746 sysctl_createv(clog, 0, NULL, NULL, 1747 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1748 CTLTYPE_INT, "checkinterface", 1749 SYSCTL_DESCR("Enable receive side of Strong ES model " 1750 "from RFC1122"), 1751 NULL, 0, &ip_checkinterface, 0, 1752 CTL_NET, PF_INET, IPPROTO_IP, 1753 IPCTL_CHECKINTERFACE, CTL_EOL); 1754 sysctl_createv(clog, 0, NULL, NULL, 1755 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1756 CTLTYPE_INT, "random_id", 1757 SYSCTL_DESCR("Assign random ip_id values"), 1758 NULL, 0, &ip_do_randomid, 0, 1759 CTL_NET, PF_INET, IPPROTO_IP, 1760 IPCTL_RANDOMID, CTL_EOL); 1761 sysctl_createv(clog, 0, NULL, NULL, 1762 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1763 CTLTYPE_INT, "do_loopback_cksum", 1764 SYSCTL_DESCR("Perform IP checksum on loopback"), 1765 NULL, 0, &ip_do_loopback_cksum, 0, 1766 CTL_NET, PF_INET, IPPROTO_IP, 1767 IPCTL_LOOPBACKCKSUM, CTL_EOL); 1768 sysctl_createv(clog, 0, NULL, NULL, 1769 CTLFLAG_PERMANENT, 1770 CTLTYPE_STRUCT, "stats", 1771 SYSCTL_DESCR("IP statistics"), 1772 sysctl_net_inet_ip_stats, 0, NULL, 0, 1773 CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS, 1774 CTL_EOL); 1775#if NARP 1776 sysctl_createv(clog, 0, NULL, NULL, 1777 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1778 CTLTYPE_INT, "dad_count", 1779 SYSCTL_DESCR("Number of Duplicate Address Detection " 1780 "probes to send"), 1781 NULL, 0, &ip_dad_count, 0, 1782 CTL_NET, PF_INET, IPPROTO_IP, 1783 IPCTL_DAD_COUNT, CTL_EOL); 1784#endif 1785 1786 /* anonportalgo RFC6056 subtree */ 1787 const struct sysctlnode *portalgo_node; 1788 sysctl_createv(clog, 0, NULL, &portalgo_node, 1789 CTLFLAG_PERMANENT, 1790 CTLTYPE_NODE, "anonportalgo", 1791 SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"), 1792 NULL, 0, NULL, 0, 1793 CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL); 1794 sysctl_createv(clog, 0, &portalgo_node, NULL, 1795 CTLFLAG_PERMANENT, 1796 CTLTYPE_STRING, "available", 1797 SYSCTL_DESCR("available algorithms"), 1798 sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN, 1799 CTL_CREATE, CTL_EOL); 1800 sysctl_createv(clog, 0, &portalgo_node, NULL, 1801 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1802 CTLTYPE_STRING, "selected", 1803 SYSCTL_DESCR("selected algorithm"), 1804 sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN, 1805 CTL_CREATE, CTL_EOL); 1806 sysctl_createv(clog, 0, &portalgo_node, NULL, 1807 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1808 CTLTYPE_STRUCT, "reserve", 1809 SYSCTL_DESCR("bitmap of reserved ports"), 1810 sysctl_portalgo_reserve4, 0, NULL, 0, 1811 CTL_CREATE, CTL_EOL); 1812} 1813 1814void 1815ip_statinc(u_int stat) 1816{ 1817 1818 KASSERT(stat < IP_NSTATS); 1819 IP_STATINC(stat); 1820} 1821