1 /* $NetBSD: ip_input.c,v 1.381 2018/04/26 19:22:17 maxv Exp $ */ 2 3 /* 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * Copyright (c) 1998 The NetBSD Foundation, Inc. 34 * All rights reserved. 35 * 36 * This code is derived from software contributed to The NetBSD Foundation 37 * by Public Access Networks Corporation ("Panix"). It was developed under 38 * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon. 39 * 40 * Redistribution and use in source and binary forms, with or without 41 * modification, are permitted provided that the following conditions 42 * are met: 43 * 1. Redistributions of source code must retain the above copyright 44 * notice, this list of conditions and the following disclaimer. 45 * 2. Redistributions in binary form must reproduce the above copyright 46 * notice, this list of conditions and the following disclaimer in the 47 * documentation and/or other materials provided with the distribution. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 50 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 51 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 52 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 53 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 54 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 55 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 56 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 57 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 58 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 59 * POSSIBILITY OF SUCH DAMAGE. 60 */ 61 62 /* 63 * Copyright (c) 1982, 1986, 1988, 1993 64 * The Regents of the University of California. All rights reserved. 65 * 66 * Redistribution and use in source and binary forms, with or without 67 * modification, are permitted provided that the following conditions 68 * are met: 69 * 1. Redistributions of source code must retain the above copyright 70 * notice, this list of conditions and the following disclaimer. 71 * 2. Redistributions in binary form must reproduce the above copyright 72 * notice, this list of conditions and the following disclaimer in the 73 * documentation and/or other materials provided with the distribution. 74 * 3. Neither the name of the University nor the names of its contributors 75 * may be used to endorse or promote products derived from this software 76 * without specific prior written permission. 77 * 78 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 79 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 80 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 81 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 82 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 83 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 84 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 85 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 86 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 87 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 88 * SUCH DAMAGE. 89 * 90 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 91 */ 92 93 #include <sys/cdefs.h> 94 __KERNEL_RCSID(0, "$NetBSD: ip_input.c,v 1.381 2018/04/26 19:22:17 maxv Exp $"); 95 96 #ifdef _KERNEL_OPT 97 #include "opt_inet.h" 98 #include "opt_gateway.h" 99 #include "opt_ipsec.h" 100 #include "opt_mrouting.h" 101 #include "opt_mbuftrace.h" 102 #include "opt_inet_csum.h" 103 #include "opt_net_mpsafe.h" 104 #endif 105 106 #include "arp.h" 107 108 #include <sys/param.h> 109 #include <sys/systm.h> 110 #include <sys/cpu.h> 111 #include <sys/mbuf.h> 112 #include <sys/domain.h> 113 #include <sys/protosw.h> 114 #include <sys/socket.h> 115 #include <sys/socketvar.h> 116 #include <sys/errno.h> 117 #include <sys/time.h> 118 #include <sys/kernel.h> 119 #include <sys/pool.h> 120 #include <sys/sysctl.h> 121 #include <sys/kauth.h> 122 123 #include <net/if.h> 124 #include <net/if_dl.h> 125 #include <net/route.h> 126 #include <net/pktqueue.h> 127 #include <net/pfil.h> 128 129 #include <netinet/in.h> 130 #include <netinet/in_systm.h> 131 #include <netinet/ip.h> 132 #include <netinet/in_pcb.h> 133 #include <netinet/in_proto.h> 134 #include <netinet/in_var.h> 135 #include <netinet/ip_var.h> 136 #include <netinet/ip_private.h> 137 #include <netinet/ip_icmp.h> 138 /* just for gif_ttl */ 139 #include <netinet/in_gif.h> 140 #include "gif.h" 141 #include <net/if_gre.h> 142 #include "gre.h" 143 144 #ifdef MROUTING 145 #include <netinet/ip_mroute.h> 146 #endif 147 #include <netinet/portalgo.h> 148 149 #ifdef IPSEC 150 #include <netipsec/ipsec.h> 151 #endif 152 153 #ifndef IPFORWARDING 154 #ifdef GATEWAY 155 #define IPFORWARDING 1 /* forward IP packets not for us */ 156 #else 157 #define IPFORWARDING 0 /* don't forward IP packets not for us */ 158 #endif 159 #endif 160 161 #define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */ 162 163 int ipforwarding = IPFORWARDING; 164 int ipsendredirects = 1; 165 int ip_defttl = IPDEFTTL; 166 int ip_forwsrcrt = 0; 167 int ip_directedbcast = 0; 168 int ip_allowsrcrt = 0; 169 int ip_mtudisc = 1; 170 int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 171 int ip_do_randomid = 0; 172 173 /* 174 * XXX - Setting ip_checkinterface mostly implements the receive side of 175 * the Strong ES model described in RFC 1122, but since the routing table 176 * and transmit implementation do not implement the Strong ES model, 177 * setting this to 1 results in an odd hybrid. 178 * 179 * XXX - ip_checkinterface currently must be disabled if you use ipnat 180 * to translate the destination address to another local interface. 181 * 182 * XXX - ip_checkinterface must be disabled if you add IP aliases 183 * to the loopback interface instead of the interface where the 184 * packets for those addresses are received. 185 */ 186 static int ip_checkinterface __read_mostly = 0; 187 188 struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 189 190 pktqueue_t * ip_pktq __read_mostly; 191 pfil_head_t * inet_pfil_hook __read_mostly; 192 ipid_state_t * ip_ids __read_mostly; 193 percpu_t * ipstat_percpu __read_mostly; 194 195 static percpu_t *ipforward_rt_percpu __cacheline_aligned; 196 197 uint16_t ip_id; 198 199 #ifdef INET_CSUM_COUNTERS 200 #include <sys/device.h> 201 202 struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 203 NULL, "inet", "hwcsum bad"); 204 struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 205 NULL, "inet", "hwcsum ok"); 206 struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 207 NULL, "inet", "swcsum"); 208 209 #define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 210 211 EVCNT_ATTACH_STATIC(ip_hwcsum_bad); 212 EVCNT_ATTACH_STATIC(ip_hwcsum_ok); 213 EVCNT_ATTACH_STATIC(ip_swcsum); 214 215 #else 216 217 #define INET_CSUM_COUNTER_INCR(ev) /* nothing */ 218 219 #endif /* INET_CSUM_COUNTERS */ 220 221 /* 222 * Used to save the IP options in case a protocol wants to respond 223 * to an incoming packet over the same route if the packet got here 224 * using IP source routing. This allows connection establishment and 225 * maintenance when the remote end is on a network that is not known 226 * to us. 227 */ 228 struct ip_srcrt { 229 int isr_nhops; /* number of hops */ 230 struct in_addr isr_dst; /* final destination */ 231 char isr_nop; /* one NOP to align */ 232 char isr_hdr[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN & OFFSET */ 233 struct in_addr isr_routes[MAX_IPOPTLEN/sizeof(struct in_addr)]; 234 }; 235 236 static int ip_drainwanted; 237 238 static void save_rte(struct mbuf *, u_char *, struct in_addr); 239 240 #ifdef MBUFTRACE 241 struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx"); 242 struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx"); 243 #endif 244 245 static void ipintr(void *); 246 static void ip_input(struct mbuf *); 247 static void ip_forward(struct mbuf *, int, struct ifnet *); 248 static bool ip_dooptions(struct mbuf *); 249 static struct in_ifaddr *ip_rtaddr(struct in_addr, struct psref *); 250 static void sysctl_net_inet_ip_setup(struct sysctllog **); 251 252 static struct in_ifaddr *ip_match_our_address(struct ifnet *, struct ip *, 253 int *); 254 static struct in_ifaddr *ip_match_our_address_broadcast(struct ifnet *, 255 struct ip *); 256 257 #ifdef NET_MPSAFE 258 #define SOFTNET_LOCK() mutex_enter(softnet_lock) 259 #define SOFTNET_UNLOCK() mutex_exit(softnet_lock) 260 #else 261 #define SOFTNET_LOCK() KASSERT(mutex_owned(softnet_lock)) 262 #define SOFTNET_UNLOCK() KASSERT(mutex_owned(softnet_lock)) 263 #endif 264 265 /* 266 * IP initialization: fill in IP protocol switch table. 267 * All protocols not implemented in kernel go to raw IP protocol handler. 268 */ 269 void 270 ip_init(void) 271 { 272 const struct protosw *pr; 273 274 in_init(); 275 sysctl_net_inet_ip_setup(NULL); 276 277 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 278 KASSERT(pr != NULL); 279 280 ip_pktq = pktq_create(IFQ_MAXLEN, ipintr, NULL); 281 KASSERT(ip_pktq != NULL); 282 283 for (u_int i = 0; i < IPPROTO_MAX; i++) { 284 ip_protox[i] = pr - inetsw; 285 } 286 for (pr = inetdomain.dom_protosw; 287 pr < inetdomain.dom_protoswNPROTOSW; pr++) 288 if (pr->pr_domain->dom_family == PF_INET && 289 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 290 ip_protox[pr->pr_protocol] = pr - inetsw; 291 292 ip_reass_init(); 293 294 ip_ids = ip_id_init(); 295 ip_id = time_uptime & 0xfffff; 296 297 #ifdef GATEWAY 298 ipflow_init(); 299 #endif 300 301 /* Register our Packet Filter hook. */ 302 inet_pfil_hook = pfil_head_create(PFIL_TYPE_AF, (void *)AF_INET); 303 KASSERT(inet_pfil_hook != NULL); 304 305 #ifdef MBUFTRACE 306 MOWNER_ATTACH(&ip_tx_mowner); 307 MOWNER_ATTACH(&ip_rx_mowner); 308 #endif 309 310 ipstat_percpu = percpu_alloc(sizeof(uint64_t) * IP_NSTATS); 311 ipforward_rt_percpu = percpu_alloc(sizeof(struct route)); 312 ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout); 313 } 314 315 static struct in_ifaddr * 316 ip_match_our_address(struct ifnet *ifp, struct ip *ip, int *downmatch) 317 { 318 struct in_ifaddr *ia = NULL; 319 int checkif; 320 321 /* 322 * Enable a consistency check between the destination address 323 * and the arrival interface for a unicast packet (the RFC 1122 324 * strong ES model) if IP forwarding is disabled and the packet 325 * is not locally generated. 326 * 327 * XXX - Checking also should be disabled if the destination 328 * address is ipnat'ed to a different interface. 329 * 330 * XXX - Checking is incompatible with IP aliases added 331 * to the loopback interface instead of the interface where 332 * the packets are received. 333 * 334 * XXX - We need to add a per ifaddr flag for this so that 335 * we get finer grain control. 336 */ 337 checkif = ip_checkinterface && (ipforwarding == 0) && 338 (ifp->if_flags & IFF_LOOPBACK) == 0; 339 340 IN_ADDRHASH_READER_FOREACH(ia, ip->ip_dst.s_addr) { 341 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) { 342 if (ia->ia4_flags & IN_IFF_NOTREADY) 343 continue; 344 if (checkif && ia->ia_ifp != ifp) 345 continue; 346 if ((ia->ia_ifp->if_flags & IFF_UP) == 0) { 347 (*downmatch)++; 348 continue; 349 } 350 if (ia->ia4_flags & IN_IFF_DETACHED && 351 (ifp->if_flags & IFF_LOOPBACK) == 0) 352 continue; 353 break; 354 } 355 } 356 357 return ia; 358 } 359 360 static struct in_ifaddr * 361 ip_match_our_address_broadcast(struct ifnet *ifp, struct ip *ip) 362 { 363 struct in_ifaddr *ia = NULL; 364 struct ifaddr *ifa; 365 366 IFADDR_READER_FOREACH(ifa, ifp) { 367 if (ifa->ifa_addr->sa_family != AF_INET) 368 continue; 369 ia = ifatoia(ifa); 370 if (ia->ia4_flags & IN_IFF_NOTREADY) 371 continue; 372 if (ia->ia4_flags & IN_IFF_DETACHED && 373 (ifp->if_flags & IFF_LOOPBACK) == 0) 374 continue; 375 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 376 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 377 /* 378 * Look for all-0's host part (old broadcast addr), 379 * either for subnet or net. 380 */ 381 ip->ip_dst.s_addr == ia->ia_subnet || 382 ip->ip_dst.s_addr == ia->ia_net) 383 goto matched; 384 /* 385 * An interface with IP address zero accepts 386 * all packets that arrive on that interface. 387 */ 388 if (in_nullhost(ia->ia_addr.sin_addr)) 389 goto matched; 390 } 391 ia = NULL; 392 393 matched: 394 return ia; 395 } 396 397 /* 398 * IP software interrupt routine. 399 */ 400 static void 401 ipintr(void *arg __unused) 402 { 403 struct mbuf *m; 404 405 KASSERT(cpu_softintr_p()); 406 407 SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE(); 408 while ((m = pktq_dequeue(ip_pktq)) != NULL) { 409 ip_input(m); 410 } 411 SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE(); 412 } 413 414 /* 415 * IP input routine. Checksum and byte swap header. If fragmented 416 * try to reassemble. Process options. Pass to next level. 417 */ 418 static void 419 ip_input(struct mbuf *m) 420 { 421 struct ip *ip = NULL; 422 struct in_ifaddr *ia = NULL; 423 int hlen = 0, len; 424 int downmatch; 425 int srcrt = 0; 426 ifnet_t *ifp; 427 struct psref psref; 428 int s; 429 430 KASSERTMSG(cpu_softintr_p(), "ip_input: not in the software " 431 "interrupt handler; synchronization assumptions violated"); 432 433 MCLAIM(m, &ip_rx_mowner); 434 KASSERT((m->m_flags & M_PKTHDR) != 0); 435 436 ifp = m_get_rcvif_psref(m, &psref); 437 if (__predict_false(ifp == NULL)) 438 goto out; 439 440 /* 441 * If no IP addresses have been set yet but the interfaces 442 * are receiving, can't do anything with incoming packets yet. 443 * Note: we pre-check without locks held. 444 */ 445 if (IN_ADDRLIST_READER_EMPTY()) 446 goto out; 447 IP_STATINC(IP_STAT_TOTAL); 448 449 /* 450 * If the IP header is not aligned, slurp it up into a new 451 * mbuf with space for link headers, in the event we forward 452 * it. Otherwise, if it is aligned, make sure the entire 453 * base IP header is in the first mbuf of the chain. 454 */ 455 if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) { 456 if ((m = m_copyup(m, sizeof(struct ip), 457 (max_linkhdr + 3) & ~3)) == NULL) { 458 /* XXXJRT new stat, please */ 459 IP_STATINC(IP_STAT_TOOSMALL); 460 goto out; 461 } 462 } else if (__predict_false(m->m_len < sizeof(struct ip))) { 463 if ((m = m_pullup(m, sizeof(struct ip))) == NULL) { 464 IP_STATINC(IP_STAT_TOOSMALL); 465 goto out; 466 } 467 } 468 ip = mtod(m, struct ip *); 469 if (ip->ip_v != IPVERSION) { 470 IP_STATINC(IP_STAT_BADVERS); 471 goto out; 472 } 473 hlen = ip->ip_hl << 2; 474 if (hlen < sizeof(struct ip)) { /* minimum header length */ 475 IP_STATINC(IP_STAT_BADHLEN); 476 goto out; 477 } 478 if (hlen > m->m_len) { 479 if ((m = m_pullup(m, hlen)) == NULL) { 480 IP_STATINC(IP_STAT_BADHLEN); 481 goto out; 482 } 483 ip = mtod(m, struct ip *); 484 } 485 486 /* 487 * RFC1122: packets with a multicast source address are 488 * not allowed. 489 */ 490 if (IN_MULTICAST(ip->ip_src.s_addr)) { 491 IP_STATINC(IP_STAT_BADADDR); 492 goto out; 493 } 494 495 /* 127/8 must not appear on wire - RFC1122 */ 496 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 497 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 498 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 499 IP_STATINC(IP_STAT_BADADDR); 500 goto out; 501 } 502 } 503 504 switch (m->m_pkthdr.csum_flags & 505 ((ifp->if_csum_flags_rx & M_CSUM_IPv4) | M_CSUM_IPv4_BAD)) { 506 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 507 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad); 508 IP_STATINC(IP_STAT_BADSUM); 509 goto out; 510 511 case M_CSUM_IPv4: 512 /* Checksum was okay. */ 513 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok); 514 break; 515 516 default: 517 /* 518 * Must compute it ourselves. Maybe skip checksum on 519 * loopback interfaces. 520 */ 521 if (__predict_true(!(ifp->if_flags & IFF_LOOPBACK) || 522 ip_do_loopback_cksum)) { 523 INET_CSUM_COUNTER_INCR(&ip_swcsum); 524 if (in_cksum(m, hlen) != 0) { 525 IP_STATINC(IP_STAT_BADSUM); 526 goto out; 527 } 528 } 529 break; 530 } 531 532 /* Retrieve the packet length. */ 533 len = ntohs(ip->ip_len); 534 535 /* 536 * Check for additional length bogosity 537 */ 538 if (len < hlen) { 539 IP_STATINC(IP_STAT_BADLEN); 540 goto out; 541 } 542 543 /* 544 * Check that the amount of data in the buffers is at least as much 545 * as the IP header would have us expect. Trim mbufs if longer than 546 * we expect. Drop packet if shorter than we expect. 547 */ 548 if (m->m_pkthdr.len < len) { 549 IP_STATINC(IP_STAT_TOOSHORT); 550 goto out; 551 } 552 if (m->m_pkthdr.len > len) { 553 if (m->m_len == m->m_pkthdr.len) { 554 m->m_len = len; 555 m->m_pkthdr.len = len; 556 } else 557 m_adj(m, len - m->m_pkthdr.len); 558 } 559 560 /* 561 * Assume that we can create a fast-forward IP flow entry 562 * based on this packet. 563 */ 564 m->m_flags |= M_CANFASTFWD; 565 566 /* 567 * Run through list of hooks for input packets. If there are any 568 * filters which require that additional packets in the flow are 569 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 570 * Note that filters must _never_ set this flag, as another filter 571 * in the list may have previously cleared it. 572 * 573 * Don't call hooks if the packet has already been processed by 574 * IPsec (encapsulated, tunnel mode). 575 */ 576 #if defined(IPSEC) 577 if (!ipsec_used || !ipsec_indone(m)) 578 #else 579 if (1) 580 #endif 581 { 582 struct in_addr odst = ip->ip_dst; 583 bool freed; 584 585 freed = pfil_run_hooks(inet_pfil_hook, &m, ifp, PFIL_IN) != 0; 586 if (freed || m == NULL) { 587 m = NULL; 588 goto out; 589 } 590 ip = mtod(m, struct ip *); 591 hlen = ip->ip_hl << 2; 592 593 /* 594 * XXX The setting of "srcrt" here is to prevent ip_forward() 595 * from generating ICMP redirects for packets that have 596 * been redirected by a hook back out on to the same LAN that 597 * they came from and is not an indication that the packet 598 * is being influenced by source routing options. This 599 * allows things like 600 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp" 601 * where tlp0 is both on the 1.1.1.0/24 network and is the 602 * default route for hosts on 1.1.1.0/24. Of course this 603 * also requires a "map tlp0 ..." to complete the story. 604 * One might argue whether or not this kind of network config. 605 * should be supported in this manner... 606 */ 607 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 608 } 609 610 #ifdef ALTQ 611 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 612 if (altq_input) { 613 SOFTNET_LOCK(); 614 if ((*altq_input)(m, AF_INET) == 0) { 615 /* Packet dropped by traffic conditioner. */ 616 SOFTNET_UNLOCK(); 617 m = NULL; 618 goto out; 619 } 620 SOFTNET_UNLOCK(); 621 } 622 #endif 623 624 /* 625 * Process options and, if not destined for us, 626 * ship it on. ip_dooptions returns 1 when an 627 * error was detected (causing an icmp message 628 * to be sent and the original packet to be freed). 629 */ 630 if (hlen > sizeof(struct ip) && ip_dooptions(m)) { 631 m = NULL; 632 goto out; 633 } 634 635 /* 636 * Check our list of addresses, to see if the packet is for us. 637 * 638 * Traditional 4.4BSD did not consult IFF_UP at all. 639 * The behavior here is to treat addresses on !IFF_UP interface 640 * or IN_IFF_NOTREADY addresses as not mine. 641 */ 642 downmatch = 0; 643 s = pserialize_read_enter(); 644 ia = ip_match_our_address(ifp, ip, &downmatch); 645 if (ia != NULL) { 646 pserialize_read_exit(s); 647 goto ours; 648 } 649 650 if (ifp->if_flags & IFF_BROADCAST) { 651 ia = ip_match_our_address_broadcast(ifp, ip); 652 if (ia != NULL) { 653 pserialize_read_exit(s); 654 goto ours; 655 } 656 } 657 pserialize_read_exit(s); 658 659 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 660 #ifdef MROUTING 661 extern struct socket *ip_mrouter; 662 663 if (ip_mrouter) { 664 /* 665 * If we are acting as a multicast router, all 666 * incoming multicast packets are passed to the 667 * kernel-level multicast forwarding function. 668 * The packet is returned (relatively) intact; if 669 * ip_mforward() returns a non-zero value, the packet 670 * must be discarded, else it may be accepted below. 671 * 672 * (The IP ident field is put in the same byte order 673 * as expected when ip_mforward() is called from 674 * ip_output().) 675 */ 676 SOFTNET_LOCK(); 677 if (ip_mforward(m, ifp) != 0) { 678 SOFTNET_UNLOCK(); 679 IP_STATINC(IP_STAT_CANTFORWARD); 680 goto out; 681 } 682 SOFTNET_UNLOCK(); 683 684 /* 685 * The process-level routing demon needs to receive 686 * all multicast IGMP packets, whether or not this 687 * host belongs to their destination groups. 688 */ 689 if (ip->ip_p == IPPROTO_IGMP) { 690 goto ours; 691 } 692 IP_STATINC(IP_STAT_CANTFORWARD); 693 } 694 #endif 695 /* 696 * See if we belong to the destination multicast group on the 697 * arrival interface. 698 */ 699 if (!in_multi_group(ip->ip_dst, ifp, 0)) { 700 IP_STATINC(IP_STAT_CANTFORWARD); 701 goto out; 702 } 703 goto ours; 704 } 705 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 706 in_nullhost(ip->ip_dst)) 707 goto ours; 708 709 /* 710 * Not for us; forward if possible and desirable. 711 */ 712 if (ipforwarding == 0) { 713 m_put_rcvif_psref(ifp, &psref); 714 IP_STATINC(IP_STAT_CANTFORWARD); 715 m_freem(m); 716 } else { 717 /* 718 * If ip_dst matched any of my address on !IFF_UP interface, 719 * and there's no IFF_UP interface that matches ip_dst, 720 * send icmp unreach. Forwarding it will result in in-kernel 721 * forwarding loop till TTL goes to 0. 722 */ 723 if (downmatch) { 724 m_put_rcvif_psref(ifp, &psref); 725 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 726 IP_STATINC(IP_STAT_CANTFORWARD); 727 return; 728 } 729 #ifdef IPSEC 730 /* Check the security policy (SP) for the packet */ 731 if (ipsec_used) { 732 if (ipsec4_input(m, IP_FORWARDING) != 0) { 733 goto out; 734 } 735 } 736 #endif 737 ip_forward(m, srcrt, ifp); 738 m_put_rcvif_psref(ifp, &psref); 739 } 740 return; 741 742 ours: 743 m_put_rcvif_psref(ifp, &psref); 744 ifp = NULL; 745 746 /* 747 * If offset or IP_MF are set, must reassemble. 748 */ 749 if (ip->ip_off & ~htons(IP_DF|IP_RF)) { 750 /* 751 * Pass to IP reassembly mechanism. 752 */ 753 if (ip_reass_packet(&m, ip) != 0) { 754 /* Failed; invalid fragment(s) or packet. */ 755 goto out; 756 } 757 if (m == NULL) { 758 /* More fragments should come; silently return. */ 759 goto out; 760 } 761 /* 762 * Reassembly is done, we have the final packet. 763 * Update cached data in local variable(s). 764 */ 765 ip = mtod(m, struct ip *); 766 hlen = ip->ip_hl << 2; 767 } 768 769 M_VERIFY_PACKET(m); 770 771 #ifdef IPSEC 772 /* 773 * Enforce IPsec policy checking if we are seeing last header. 774 * Note that we do not visit this with protocols with PCB layer 775 * code - like UDP/TCP/raw IP. 776 */ 777 if (ipsec_used && 778 (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 779 if (ipsec4_input(m, 0) != 0) { 780 goto out; 781 } 782 } 783 #endif 784 785 /* 786 * Switch out to protocol's input routine. 787 */ 788 #if IFA_STATS 789 if (ia) { 790 struct in_ifaddr *_ia; 791 /* 792 * Keep a reference from ip_match_our_address with psref 793 * is expensive, so explore ia here again. 794 */ 795 s = pserialize_read_enter(); 796 _ia = in_get_ia(ip->ip_dst); 797 _ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len); 798 pserialize_read_exit(s); 799 } 800 #endif 801 IP_STATINC(IP_STAT_DELIVERED); 802 803 const int off = hlen, nh = ip->ip_p; 804 805 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 806 return; 807 808 out: 809 m_put_rcvif_psref(ifp, &psref); 810 if (m != NULL) 811 m_freem(m); 812 } 813 814 /* 815 * IP timer processing. 816 */ 817 void 818 ip_slowtimo(void) 819 { 820 821 SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE(); 822 823 ip_reass_slowtimo(); 824 825 SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE(); 826 } 827 828 /* 829 * IP drain processing. 830 */ 831 void 832 ip_drain(void) 833 { 834 835 KERNEL_LOCK(1, NULL); 836 ip_reass_drain(); 837 KERNEL_UNLOCK_ONE(NULL); 838 } 839 840 /* 841 * ip_dooptions: perform option processing on a datagram, possibly discarding 842 * it if bad options are encountered, or forwarding it if source-routed. 843 * 844 * => Returns true if packet has been forwarded/freed. 845 * => Returns false if the packet should be processed further. 846 */ 847 static bool 848 ip_dooptions(struct mbuf *m) 849 { 850 struct ip *ip = mtod(m, struct ip *); 851 u_char *cp, *cp0; 852 struct ip_timestamp *ipt; 853 struct in_ifaddr *ia; 854 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 855 int srr_present, rr_present, ts_present; 856 struct in_addr dst; 857 n_time ntime; 858 struct ifaddr *ifa = NULL; 859 int s; 860 861 srr_present = 0; 862 rr_present = 0; 863 ts_present = 0; 864 865 dst = ip->ip_dst; 866 cp = (u_char *)(ip + 1); 867 cnt = (ip->ip_hl << 2) - sizeof(struct ip); 868 for (; cnt > 0; cnt -= optlen, cp += optlen) { 869 opt = cp[IPOPT_OPTVAL]; 870 if (opt == IPOPT_EOL) 871 break; 872 if (opt == IPOPT_NOP) 873 optlen = 1; 874 else { 875 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 876 code = &cp[IPOPT_OLEN] - (u_char *)ip; 877 goto bad; 878 } 879 optlen = cp[IPOPT_OLEN]; 880 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 881 code = &cp[IPOPT_OLEN] - (u_char *)ip; 882 goto bad; 883 } 884 } 885 switch (opt) { 886 887 default: 888 break; 889 890 /* 891 * Source routing with record. 892 * Find interface with current destination address. 893 * If none on this machine then drop if strictly routed, 894 * or do nothing if loosely routed. 895 * Record interface address and bring up next address 896 * component. If strictly routed make sure next 897 * address is on directly accessible net. 898 */ 899 case IPOPT_LSRR: 900 case IPOPT_SSRR: { 901 struct psref psref; 902 struct sockaddr_in ipaddr = { 903 .sin_len = sizeof(ipaddr), 904 .sin_family = AF_INET, 905 }; 906 907 if (ip_allowsrcrt == 0) { 908 type = ICMP_UNREACH; 909 code = ICMP_UNREACH_NET_PROHIB; 910 goto bad; 911 } 912 if (srr_present++) { 913 code = &cp[IPOPT_OPTVAL] - (u_char *)ip; 914 goto bad; 915 } 916 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 917 code = &cp[IPOPT_OLEN] - (u_char *)ip; 918 goto bad; 919 } 920 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 921 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 922 goto bad; 923 } 924 ipaddr.sin_addr = ip->ip_dst; 925 926 s = pserialize_read_enter(); 927 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 928 if (ifa == NULL) { 929 pserialize_read_exit(s); 930 if (opt == IPOPT_SSRR) { 931 type = ICMP_UNREACH; 932 code = ICMP_UNREACH_SRCFAIL; 933 goto bad; 934 } 935 /* 936 * Loose routing, and not at next destination 937 * yet; nothing to do except forward. 938 */ 939 break; 940 } 941 pserialize_read_exit(s); 942 943 off--; /* 0 origin */ 944 if ((off + sizeof(struct in_addr)) > optlen) { 945 /* 946 * End of source route. Should be for us. 947 */ 948 save_rte(m, cp, ip->ip_src); 949 break; 950 } 951 /* 952 * locate outgoing interface 953 */ 954 memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off), 955 sizeof(ipaddr.sin_addr)); 956 if (opt == IPOPT_SSRR) { 957 ifa = ifa_ifwithladdr_psref(sintosa(&ipaddr), 958 &psref); 959 if (ifa != NULL) 960 ia = ifatoia(ifa); 961 else 962 ia = NULL; 963 } else { 964 ia = ip_rtaddr(ipaddr.sin_addr, &psref); 965 } 966 if (ia == NULL) { 967 type = ICMP_UNREACH; 968 code = ICMP_UNREACH_SRCFAIL; 969 goto bad; 970 } 971 ip->ip_dst = ipaddr.sin_addr; 972 memcpy(cp + off, &ia->ia_addr.sin_addr, 973 sizeof(struct in_addr)); 974 ia4_release(ia, &psref); 975 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 976 /* 977 * Let ip_intr's mcast routing check handle mcast pkts 978 */ 979 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 980 break; 981 } 982 983 case IPOPT_RR: { 984 struct psref psref; 985 struct sockaddr_in ipaddr = { 986 .sin_len = sizeof(ipaddr), 987 .sin_family = AF_INET, 988 }; 989 990 if (rr_present++) { 991 code = &cp[IPOPT_OPTVAL] - (u_char *)ip; 992 goto bad; 993 } 994 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 995 code = &cp[IPOPT_OLEN] - (u_char *)ip; 996 goto bad; 997 } 998 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 999 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1000 goto bad; 1001 } 1002 /* 1003 * If no space remains, ignore. 1004 */ 1005 off--; /* 0 origin */ 1006 if ((off + sizeof(struct in_addr)) > optlen) 1007 break; 1008 memcpy((void *)&ipaddr.sin_addr, (void *)&ip->ip_dst, 1009 sizeof(ipaddr.sin_addr)); 1010 /* 1011 * locate outgoing interface; if we're the destination, 1012 * use the incoming interface (should be same). 1013 */ 1014 ifa = ifa_ifwithaddr_psref(sintosa(&ipaddr), &psref); 1015 if (ifa == NULL) { 1016 ia = ip_rtaddr(ipaddr.sin_addr, &psref); 1017 if (ia == NULL) { 1018 type = ICMP_UNREACH; 1019 code = ICMP_UNREACH_HOST; 1020 goto bad; 1021 } 1022 } else { 1023 ia = ifatoia(ifa); 1024 } 1025 memcpy(cp + off, &ia->ia_addr.sin_addr, 1026 sizeof(struct in_addr)); 1027 ia4_release(ia, &psref); 1028 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1029 break; 1030 } 1031 1032 case IPOPT_TS: 1033 code = cp - (u_char *)ip; 1034 ipt = (struct ip_timestamp *)cp; 1035 if (ts_present++) { 1036 code = &cp[IPOPT_OPTVAL] - (u_char *)ip; 1037 goto bad; 1038 } 1039 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1040 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1041 goto bad; 1042 } 1043 if (ipt->ipt_ptr < 5) { 1044 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1045 goto bad; 1046 } 1047 if (ipt->ipt_ptr > ipt->ipt_len - sizeof(int32_t)) { 1048 if (++ipt->ipt_oflw == 0) { 1049 code = (u_char *)&ipt->ipt_ptr - 1050 (u_char *)ip; 1051 goto bad; 1052 } 1053 break; 1054 } 1055 cp0 = (cp + ipt->ipt_ptr - 1); 1056 switch (ipt->ipt_flg) { 1057 1058 case IPOPT_TS_TSONLY: 1059 break; 1060 1061 case IPOPT_TS_TSANDADDR: { 1062 struct ifnet *rcvif; 1063 int _s, _ss; 1064 struct sockaddr_in ipaddr = { 1065 .sin_len = sizeof(ipaddr), 1066 .sin_family = AF_INET, 1067 }; 1068 1069 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1070 sizeof(struct in_addr) > ipt->ipt_len) { 1071 code = (u_char *)&ipt->ipt_ptr - 1072 (u_char *)ip; 1073 goto bad; 1074 } 1075 ipaddr.sin_addr = dst; 1076 _ss = pserialize_read_enter(); 1077 rcvif = m_get_rcvif(m, &_s); 1078 if (__predict_true(rcvif != NULL)) { 1079 ifa = ifaof_ifpforaddr(sintosa(&ipaddr), 1080 rcvif); 1081 } 1082 m_put_rcvif(rcvif, &_s); 1083 if (ifa == NULL) { 1084 pserialize_read_exit(_ss); 1085 break; 1086 } 1087 ia = ifatoia(ifa); 1088 memcpy(cp0, &ia->ia_addr.sin_addr, 1089 sizeof(struct in_addr)); 1090 pserialize_read_exit(_ss); 1091 ipt->ipt_ptr += sizeof(struct in_addr); 1092 break; 1093 } 1094 1095 case IPOPT_TS_PRESPEC: { 1096 struct sockaddr_in ipaddr = { 1097 .sin_len = sizeof(ipaddr), 1098 .sin_family = AF_INET, 1099 }; 1100 1101 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1102 sizeof(struct in_addr) > ipt->ipt_len) { 1103 code = (u_char *)&ipt->ipt_ptr - 1104 (u_char *)ip; 1105 goto bad; 1106 } 1107 memcpy(&ipaddr.sin_addr, cp0, 1108 sizeof(struct in_addr)); 1109 s = pserialize_read_enter(); 1110 ifa = ifa_ifwithaddr(sintosa(&ipaddr)); 1111 if (ifa == NULL) { 1112 pserialize_read_exit(s); 1113 continue; 1114 } 1115 pserialize_read_exit(s); 1116 ipt->ipt_ptr += sizeof(struct in_addr); 1117 break; 1118 } 1119 1120 default: 1121 /* XXX can't take &ipt->ipt_flg */ 1122 code = (u_char *)&ipt->ipt_ptr - 1123 (u_char *)ip + 1; 1124 goto bad; 1125 } 1126 ntime = iptime(); 1127 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1128 memmove((char *)cp + ipt->ipt_ptr - 1, cp0, 1129 sizeof(n_time)); 1130 ipt->ipt_ptr += sizeof(n_time); 1131 } 1132 } 1133 if (forward) { 1134 struct ifnet *rcvif; 1135 struct psref _psref; 1136 1137 if (ip_forwsrcrt == 0) { 1138 type = ICMP_UNREACH; 1139 code = ICMP_UNREACH_SRCFAIL; 1140 goto bad; 1141 } 1142 1143 rcvif = m_get_rcvif_psref(m, &_psref); 1144 if (__predict_false(rcvif == NULL)) { 1145 type = ICMP_UNREACH; 1146 code = ICMP_UNREACH_HOST; 1147 goto bad; 1148 } 1149 ip_forward(m, 1, rcvif); 1150 m_put_rcvif_psref(rcvif, &_psref); 1151 return true; 1152 } 1153 return false; 1154 bad: 1155 icmp_error(m, type, code, 0, 0); 1156 IP_STATINC(IP_STAT_BADOPTIONS); 1157 return true; 1158 } 1159 1160 /* 1161 * ip_rtaddr: given address of next destination (final or next hop), 1162 * return internet address info of interface to be used to get there. 1163 */ 1164 static struct in_ifaddr * 1165 ip_rtaddr(struct in_addr dst, struct psref *psref) 1166 { 1167 struct rtentry *rt; 1168 union { 1169 struct sockaddr dst; 1170 struct sockaddr_in dst4; 1171 } u; 1172 struct route *ro; 1173 1174 sockaddr_in_init(&u.dst4, &dst, 0); 1175 1176 ro = percpu_getref(ipforward_rt_percpu); 1177 rt = rtcache_lookup(ro, &u.dst); 1178 if (rt == NULL) { 1179 percpu_putref(ipforward_rt_percpu); 1180 return NULL; 1181 } 1182 1183 ia4_acquire(ifatoia(rt->rt_ifa), psref); 1184 rtcache_unref(rt, ro); 1185 percpu_putref(ipforward_rt_percpu); 1186 1187 return ifatoia(rt->rt_ifa); 1188 } 1189 1190 /* 1191 * save_rte: save incoming source route for use in replies, to be picked 1192 * up later by ip_srcroute if the receiver is interested. 1193 */ 1194 static void 1195 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1196 { 1197 struct ip_srcrt *isr; 1198 struct m_tag *mtag; 1199 unsigned olen; 1200 1201 olen = option[IPOPT_OLEN]; 1202 if (olen > sizeof(isr->isr_hdr) + sizeof(isr->isr_routes)) 1203 return; 1204 1205 mtag = m_tag_get(PACKET_TAG_SRCROUTE, sizeof(*isr), M_NOWAIT); 1206 if (mtag == NULL) 1207 return; 1208 isr = (struct ip_srcrt *)(mtag + 1); 1209 1210 memcpy(isr->isr_hdr, option, olen); 1211 isr->isr_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1212 isr->isr_dst = dst; 1213 m_tag_prepend(m, mtag); 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 */ 1221 struct mbuf * 1222 ip_srcroute(struct mbuf *m0) 1223 { 1224 struct in_addr *p, *q; 1225 struct mbuf *m; 1226 struct ip_srcrt *isr; 1227 struct m_tag *mtag; 1228 1229 mtag = m_tag_find(m0, PACKET_TAG_SRCROUTE, NULL); 1230 if (mtag == NULL) 1231 return NULL; 1232 isr = (struct ip_srcrt *)(mtag + 1); 1233 1234 if (isr->isr_nhops == 0) 1235 return NULL; 1236 1237 m = m_get(M_DONTWAIT, MT_SOOPTS); 1238 if (m == NULL) 1239 return NULL; 1240 1241 MCLAIM(m, &inetdomain.dom_mowner); 1242 #define OPTSIZ (sizeof(isr->isr_nop) + sizeof(isr->isr_hdr)) 1243 1244 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + header) */ 1245 m->m_len = (isr->isr_nhops + 1) * sizeof(struct in_addr) + OPTSIZ; 1246 1247 /* 1248 * First save first hop for return route 1249 */ 1250 p = &(isr->isr_routes[isr->isr_nhops - 1]); 1251 *(mtod(m, struct in_addr *)) = *p--; 1252 1253 /* 1254 * Copy option fields and padding (nop) to mbuf. 1255 */ 1256 isr->isr_nop = IPOPT_NOP; 1257 isr->isr_hdr[IPOPT_OFFSET] = IPOPT_MINOFF; 1258 memmove(mtod(m, char *) + sizeof(struct in_addr), &isr->isr_nop, 1259 OPTSIZ); 1260 q = (struct in_addr *)(mtod(m, char *) + 1261 sizeof(struct in_addr) + OPTSIZ); 1262 #undef OPTSIZ 1263 /* 1264 * Record return path as an IP source route, 1265 * reversing the path (pointers are now aligned). 1266 */ 1267 while (p >= isr->isr_routes) { 1268 *q++ = *p--; 1269 } 1270 /* 1271 * Last hop goes to final destination. 1272 */ 1273 *q = isr->isr_dst; 1274 m_tag_delete(m0, mtag); 1275 return m; 1276 } 1277 1278 const int inetctlerrmap[PRC_NCMDS] = { 1279 [PRC_MSGSIZE] = EMSGSIZE, 1280 [PRC_HOSTDEAD] = EHOSTDOWN, 1281 [PRC_HOSTUNREACH] = EHOSTUNREACH, 1282 [PRC_UNREACH_NET] = EHOSTUNREACH, 1283 [PRC_UNREACH_HOST] = EHOSTUNREACH, 1284 [PRC_UNREACH_PROTOCOL] = ECONNREFUSED, 1285 [PRC_UNREACH_PORT] = ECONNREFUSED, 1286 [PRC_UNREACH_SRCFAIL] = EHOSTUNREACH, 1287 [PRC_PARAMPROB] = ENOPROTOOPT, 1288 }; 1289 1290 void 1291 ip_fasttimo(void) 1292 { 1293 if (ip_drainwanted) { 1294 ip_drain(); 1295 ip_drainwanted = 0; 1296 } 1297 } 1298 1299 void 1300 ip_drainstub(void) 1301 { 1302 ip_drainwanted = 1; 1303 } 1304 1305 /* 1306 * Forward a packet. If some error occurs return the sender 1307 * an icmp packet. Note we can't always generate a meaningful 1308 * icmp message because icmp doesn't have a large enough repertoire 1309 * of codes and types. 1310 * 1311 * If not forwarding, just drop the packet. This could be confusing 1312 * if ipforwarding was zero but some routing protocol was advancing 1313 * us as a gateway to somewhere. However, we must let the routing 1314 * protocol deal with that. 1315 * 1316 * The srcrt parameter indicates whether the packet is being forwarded 1317 * via a source route. 1318 */ 1319 static void 1320 ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif) 1321 { 1322 struct ip *ip = mtod(m, struct ip *); 1323 struct rtentry *rt; 1324 int error, type = 0, code = 0, destmtu = 0; 1325 struct mbuf *mcopy; 1326 n_long dest; 1327 union { 1328 struct sockaddr dst; 1329 struct sockaddr_in dst4; 1330 } u; 1331 uint64_t *ips; 1332 struct route *ro; 1333 1334 KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software " 1335 "interrupt handler; synchronization assumptions violated"); 1336 1337 /* 1338 * We are now in the output path. 1339 */ 1340 MCLAIM(m, &ip_tx_mowner); 1341 1342 /* 1343 * Clear any in-bound checksum flags for this packet. 1344 */ 1345 m->m_pkthdr.csum_flags = 0; 1346 1347 dest = 0; 1348 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1349 IP_STATINC(IP_STAT_CANTFORWARD); 1350 m_freem(m); 1351 return; 1352 } 1353 1354 if (ip->ip_ttl <= IPTTLDEC) { 1355 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1356 return; 1357 } 1358 1359 sockaddr_in_init(&u.dst4, &ip->ip_dst, 0); 1360 1361 ro = percpu_getref(ipforward_rt_percpu); 1362 rt = rtcache_lookup(ro, &u.dst); 1363 if (rt == NULL) { 1364 percpu_putref(ipforward_rt_percpu); 1365 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0); 1366 return; 1367 } 1368 1369 /* 1370 * Save at most 68 bytes of the packet in case 1371 * we need to generate an ICMP message to the src. 1372 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1373 */ 1374 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1375 if (mcopy) 1376 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1377 1378 ip->ip_ttl -= IPTTLDEC; 1379 1380 /* 1381 * If forwarding packet using same interface that it came in on, 1382 * perhaps should send a redirect to sender to shortcut a hop. 1383 * Only send redirect if source is sending directly to us, 1384 * and if packet was not source routed (or has any options). 1385 * Also, don't send redirect if forwarding using a default route 1386 * or a route modified by a redirect. 1387 */ 1388 if (rt->rt_ifp == rcvif && 1389 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1390 !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) && 1391 ipsendredirects && !srcrt) { 1392 if (rt->rt_ifa && 1393 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1394 ifatoia(rt->rt_ifa)->ia_subnet) { 1395 if (rt->rt_flags & RTF_GATEWAY) 1396 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1397 else 1398 dest = ip->ip_dst.s_addr; 1399 /* 1400 * Router requirements says to only send host 1401 * redirects. 1402 */ 1403 type = ICMP_REDIRECT; 1404 code = ICMP_REDIRECT_HOST; 1405 } 1406 } 1407 rtcache_unref(rt, ro); 1408 1409 error = ip_output(m, NULL, ro, 1410 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1411 NULL, NULL); 1412 1413 if (error) { 1414 IP_STATINC(IP_STAT_CANTFORWARD); 1415 goto error; 1416 } 1417 1418 ips = IP_STAT_GETREF(); 1419 ips[IP_STAT_FORWARD]++; 1420 1421 if (type) { 1422 ips[IP_STAT_REDIRECTSENT]++; 1423 IP_STAT_PUTREF(); 1424 goto redirect; 1425 } 1426 1427 IP_STAT_PUTREF(); 1428 if (mcopy) { 1429 #ifdef GATEWAY 1430 if (mcopy->m_flags & M_CANFASTFWD) 1431 ipflow_create(ro, mcopy); 1432 #endif 1433 m_freem(mcopy); 1434 } 1435 1436 percpu_putref(ipforward_rt_percpu); 1437 return; 1438 1439 redirect: 1440 error: 1441 if (mcopy == NULL) { 1442 percpu_putref(ipforward_rt_percpu); 1443 return; 1444 } 1445 1446 switch (error) { 1447 1448 case 0: /* forwarded, but need redirect */ 1449 /* type, code set above */ 1450 break; 1451 1452 case ENETUNREACH: /* shouldn't happen, checked above */ 1453 case EHOSTUNREACH: 1454 case ENETDOWN: 1455 case EHOSTDOWN: 1456 default: 1457 type = ICMP_UNREACH; 1458 code = ICMP_UNREACH_HOST; 1459 break; 1460 1461 case EMSGSIZE: 1462 type = ICMP_UNREACH; 1463 code = ICMP_UNREACH_NEEDFRAG; 1464 1465 if ((rt = rtcache_validate(ro)) != NULL) { 1466 destmtu = rt->rt_ifp->if_mtu; 1467 rtcache_unref(rt, ro); 1468 } 1469 #ifdef IPSEC 1470 if (ipsec_used) 1471 (void)ipsec4_forward(mcopy, &destmtu); 1472 #endif 1473 IP_STATINC(IP_STAT_CANTFRAG); 1474 break; 1475 1476 case ENOBUFS: 1477 /* 1478 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812, 1479 * Requirements for IP Version 4 Routers. Source quench can 1480 * be a big problem under DoS attacks or if the underlying 1481 * interface is rate-limited. 1482 */ 1483 if (mcopy) 1484 m_freem(mcopy); 1485 percpu_putref(ipforward_rt_percpu); 1486 return; 1487 } 1488 icmp_error(mcopy, type, code, dest, destmtu); 1489 percpu_putref(ipforward_rt_percpu); 1490 } 1491 1492 void 1493 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1494 struct mbuf *m) 1495 { 1496 struct socket *so = inp->inp_socket; 1497 int inpflags = inp->inp_flags; 1498 1499 if (SOOPT_TIMESTAMP(so->so_options)) 1500 mp = sbsavetimestamp(so->so_options, mp); 1501 1502 if (inpflags & INP_RECVDSTADDR) { 1503 *mp = sbcreatecontrol(&ip->ip_dst, 1504 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1505 if (*mp) 1506 mp = &(*mp)->m_next; 1507 } 1508 1509 if (inpflags & INP_RECVTTL) { 1510 *mp = sbcreatecontrol(&ip->ip_ttl, 1511 sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP); 1512 if (*mp) 1513 mp = &(*mp)->m_next; 1514 } 1515 1516 struct psref psref; 1517 ifnet_t *ifp = m_get_rcvif_psref(m, &psref); 1518 if (__predict_false(ifp == NULL)) { 1519 #ifdef DIAGNOSTIC 1520 printf("%s: missing receive interface\n", __func__); 1521 #endif 1522 return; /* XXX should report error? */ 1523 } 1524 1525 if (inpflags & INP_RECVPKTINFO) { 1526 struct in_pktinfo ipi; 1527 ipi.ipi_addr = ip->ip_dst; 1528 ipi.ipi_ifindex = ifp->if_index; 1529 *mp = sbcreatecontrol(&ipi, 1530 sizeof(ipi), IP_PKTINFO, IPPROTO_IP); 1531 if (*mp) 1532 mp = &(*mp)->m_next; 1533 } 1534 if (inpflags & INP_RECVIF) { 1535 struct sockaddr_dl sdl; 1536 1537 sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0, 1538 NULL, 0); 1539 *mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP); 1540 if (*mp) 1541 mp = &(*mp)->m_next; 1542 } 1543 m_put_rcvif_psref(ifp, &psref); 1544 } 1545 1546 /* 1547 * sysctl helper routine for net.inet.ip.forwsrcrt. 1548 */ 1549 static int 1550 sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS) 1551 { 1552 int error, tmp; 1553 struct sysctlnode node; 1554 1555 node = *rnode; 1556 tmp = ip_forwsrcrt; 1557 node.sysctl_data = &tmp; 1558 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1559 if (error || newp == NULL) 1560 return (error); 1561 1562 error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT, 1563 0, NULL, NULL, NULL); 1564 if (error) 1565 return (error); 1566 1567 ip_forwsrcrt = tmp; 1568 1569 return (0); 1570 } 1571 1572 /* 1573 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the 1574 * range of the new value and tweaks timers if it changes. 1575 */ 1576 static int 1577 sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS) 1578 { 1579 int error, tmp; 1580 struct sysctlnode node; 1581 1582 icmp_mtudisc_lock(); 1583 1584 node = *rnode; 1585 tmp = ip_mtudisc_timeout; 1586 node.sysctl_data = &tmp; 1587 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1588 if (error || newp == NULL) 1589 goto out; 1590 if (tmp < 0) { 1591 error = EINVAL; 1592 goto out; 1593 } 1594 1595 ip_mtudisc_timeout = tmp; 1596 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout); 1597 error = 0; 1598 out: 1599 icmp_mtudisc_unlock(); 1600 return error; 1601 } 1602 1603 static int 1604 sysctl_net_inet_ip_stats(SYSCTLFN_ARGS) 1605 { 1606 1607 return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS)); 1608 } 1609 1610 static void 1611 sysctl_net_inet_ip_setup(struct sysctllog **clog) 1612 { 1613 sysctl_createv(clog, 0, NULL, NULL, 1614 CTLFLAG_PERMANENT, 1615 CTLTYPE_NODE, "inet", 1616 SYSCTL_DESCR("PF_INET related settings"), 1617 NULL, 0, NULL, 0, 1618 CTL_NET, PF_INET, CTL_EOL); 1619 sysctl_createv(clog, 0, NULL, NULL, 1620 CTLFLAG_PERMANENT, 1621 CTLTYPE_NODE, "ip", 1622 SYSCTL_DESCR("IPv4 related settings"), 1623 NULL, 0, NULL, 0, 1624 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL); 1625 1626 sysctl_createv(clog, 0, NULL, NULL, 1627 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1628 CTLTYPE_INT, "forwarding", 1629 SYSCTL_DESCR("Enable forwarding of INET datagrams"), 1630 NULL, 0, &ipforwarding, 0, 1631 CTL_NET, PF_INET, IPPROTO_IP, 1632 IPCTL_FORWARDING, CTL_EOL); 1633 sysctl_createv(clog, 0, NULL, NULL, 1634 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1635 CTLTYPE_INT, "redirect", 1636 SYSCTL_DESCR("Enable sending of ICMP redirect messages"), 1637 NULL, 0, &ipsendredirects, 0, 1638 CTL_NET, PF_INET, IPPROTO_IP, 1639 IPCTL_SENDREDIRECTS, CTL_EOL); 1640 sysctl_createv(clog, 0, NULL, NULL, 1641 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1642 CTLTYPE_INT, "ttl", 1643 SYSCTL_DESCR("Default TTL for an INET datagram"), 1644 NULL, 0, &ip_defttl, 0, 1645 CTL_NET, PF_INET, IPPROTO_IP, 1646 IPCTL_DEFTTL, CTL_EOL); 1647 sysctl_createv(clog, 0, NULL, NULL, 1648 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1649 CTLTYPE_INT, "forwsrcrt", 1650 SYSCTL_DESCR("Enable forwarding of source-routed " 1651 "datagrams"), 1652 sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0, 1653 CTL_NET, PF_INET, IPPROTO_IP, 1654 IPCTL_FORWSRCRT, CTL_EOL); 1655 sysctl_createv(clog, 0, NULL, NULL, 1656 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1657 CTLTYPE_INT, "directed-broadcast", 1658 SYSCTL_DESCR("Enable forwarding of broadcast datagrams"), 1659 NULL, 0, &ip_directedbcast, 0, 1660 CTL_NET, PF_INET, IPPROTO_IP, 1661 IPCTL_DIRECTEDBCAST, CTL_EOL); 1662 sysctl_createv(clog, 0, NULL, NULL, 1663 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1664 CTLTYPE_INT, "allowsrcrt", 1665 SYSCTL_DESCR("Accept source-routed datagrams"), 1666 NULL, 0, &ip_allowsrcrt, 0, 1667 CTL_NET, PF_INET, IPPROTO_IP, 1668 IPCTL_ALLOWSRCRT, CTL_EOL); 1669 1670 sysctl_createv(clog, 0, NULL, NULL, 1671 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1672 CTLTYPE_INT, "mtudisc", 1673 SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"), 1674 NULL, 0, &ip_mtudisc, 0, 1675 CTL_NET, PF_INET, IPPROTO_IP, 1676 IPCTL_MTUDISC, CTL_EOL); 1677 sysctl_createv(clog, 0, NULL, NULL, 1678 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1679 CTLTYPE_INT, "anonportmin", 1680 SYSCTL_DESCR("Lowest ephemeral port number to assign"), 1681 sysctl_net_inet_ip_ports, 0, &anonportmin, 0, 1682 CTL_NET, PF_INET, IPPROTO_IP, 1683 IPCTL_ANONPORTMIN, CTL_EOL); 1684 sysctl_createv(clog, 0, NULL, NULL, 1685 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1686 CTLTYPE_INT, "anonportmax", 1687 SYSCTL_DESCR("Highest ephemeral port number to assign"), 1688 sysctl_net_inet_ip_ports, 0, &anonportmax, 0, 1689 CTL_NET, PF_INET, IPPROTO_IP, 1690 IPCTL_ANONPORTMAX, CTL_EOL); 1691 sysctl_createv(clog, 0, NULL, NULL, 1692 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1693 CTLTYPE_INT, "mtudisctimeout", 1694 SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"), 1695 sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0, 1696 CTL_NET, PF_INET, IPPROTO_IP, 1697 IPCTL_MTUDISCTIMEOUT, CTL_EOL); 1698 #ifndef IPNOPRIVPORTS 1699 sysctl_createv(clog, 0, NULL, NULL, 1700 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1701 CTLTYPE_INT, "lowportmin", 1702 SYSCTL_DESCR("Lowest privileged ephemeral port number " 1703 "to assign"), 1704 sysctl_net_inet_ip_ports, 0, &lowportmin, 0, 1705 CTL_NET, PF_INET, IPPROTO_IP, 1706 IPCTL_LOWPORTMIN, CTL_EOL); 1707 sysctl_createv(clog, 0, NULL, NULL, 1708 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1709 CTLTYPE_INT, "lowportmax", 1710 SYSCTL_DESCR("Highest privileged ephemeral port number " 1711 "to assign"), 1712 sysctl_net_inet_ip_ports, 0, &lowportmax, 0, 1713 CTL_NET, PF_INET, IPPROTO_IP, 1714 IPCTL_LOWPORTMAX, CTL_EOL); 1715 #endif /* IPNOPRIVPORTS */ 1716 #if NGRE > 0 1717 sysctl_createv(clog, 0, NULL, NULL, 1718 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1719 CTLTYPE_INT, "grettl", 1720 SYSCTL_DESCR("Default TTL for a gre tunnel datagram"), 1721 NULL, 0, &ip_gre_ttl, 0, 1722 CTL_NET, PF_INET, IPPROTO_IP, 1723 IPCTL_GRE_TTL, CTL_EOL); 1724 #endif /* NGRE */ 1725 sysctl_createv(clog, 0, NULL, NULL, 1726 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1727 CTLTYPE_INT, "checkinterface", 1728 SYSCTL_DESCR("Enable receive side of Strong ES model " 1729 "from RFC1122"), 1730 NULL, 0, &ip_checkinterface, 0, 1731 CTL_NET, PF_INET, IPPROTO_IP, 1732 IPCTL_CHECKINTERFACE, CTL_EOL); 1733 sysctl_createv(clog, 0, NULL, NULL, 1734 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1735 CTLTYPE_INT, "random_id", 1736 SYSCTL_DESCR("Assign random ip_id values"), 1737 NULL, 0, &ip_do_randomid, 0, 1738 CTL_NET, PF_INET, IPPROTO_IP, 1739 IPCTL_RANDOMID, CTL_EOL); 1740 sysctl_createv(clog, 0, NULL, NULL, 1741 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1742 CTLTYPE_INT, "do_loopback_cksum", 1743 SYSCTL_DESCR("Perform IP checksum on loopback"), 1744 NULL, 0, &ip_do_loopback_cksum, 0, 1745 CTL_NET, PF_INET, IPPROTO_IP, 1746 IPCTL_LOOPBACKCKSUM, CTL_EOL); 1747 sysctl_createv(clog, 0, NULL, NULL, 1748 CTLFLAG_PERMANENT, 1749 CTLTYPE_STRUCT, "stats", 1750 SYSCTL_DESCR("IP statistics"), 1751 sysctl_net_inet_ip_stats, 0, NULL, 0, 1752 CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS, 1753 CTL_EOL); 1754 #if NARP 1755 sysctl_createv(clog, 0, NULL, NULL, 1756 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1757 CTLTYPE_INT, "dad_count", 1758 SYSCTL_DESCR("Number of Duplicate Address Detection " 1759 "probes to send"), 1760 NULL, 0, &ip_dad_count, 0, 1761 CTL_NET, PF_INET, IPPROTO_IP, 1762 IPCTL_DAD_COUNT, CTL_EOL); 1763 #endif 1764 1765 /* anonportalgo RFC6056 subtree */ 1766 const struct sysctlnode *portalgo_node; 1767 sysctl_createv(clog, 0, NULL, &portalgo_node, 1768 CTLFLAG_PERMANENT, 1769 CTLTYPE_NODE, "anonportalgo", 1770 SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"), 1771 NULL, 0, NULL, 0, 1772 CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL); 1773 sysctl_createv(clog, 0, &portalgo_node, NULL, 1774 CTLFLAG_PERMANENT, 1775 CTLTYPE_STRING, "available", 1776 SYSCTL_DESCR("available algorithms"), 1777 sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN, 1778 CTL_CREATE, CTL_EOL); 1779 sysctl_createv(clog, 0, &portalgo_node, NULL, 1780 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1781 CTLTYPE_STRING, "selected", 1782 SYSCTL_DESCR("selected algorithm"), 1783 sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN, 1784 CTL_CREATE, CTL_EOL); 1785 sysctl_createv(clog, 0, &portalgo_node, NULL, 1786 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1787 CTLTYPE_STRUCT, "reserve", 1788 SYSCTL_DESCR("bitmap of reserved ports"), 1789 sysctl_portalgo_reserve4, 0, NULL, 0, 1790 CTL_CREATE, CTL_EOL); 1791 } 1792 1793 void 1794 ip_statinc(u_int stat) 1795 { 1796 1797 KASSERT(stat < IP_NSTATS); 1798 IP_STATINC(stat); 1799 } 1800