1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_bootp.h" 36 #include "opt_ipfw.h" 37 #include "opt_ipstealth.h" 38 #include "opt_ipsec.h" 39 #include "opt_mac.h" 40 #include "opt_carp.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/callout.h> 45 #include <sys/mbuf.h> 46 #include <sys/malloc.h> 47 #include <sys/domain.h> 48 #include <sys/protosw.h> 49 #include <sys/socket.h> 50 #include <sys/time.h> 51 #include <sys/kernel.h> 52 #include <sys/syslog.h> 53 #include <sys/sysctl.h> 54 #include <sys/vimage.h> 55 56 #include <net/pfil.h> 57 #include <net/if.h> 58 #include <net/if_types.h> 59 #include <net/if_var.h> 60 #include <net/if_dl.h> 61 #include <net/route.h> 62 #include <net/netisr.h> 63 #include <net/vnet.h> 64 65 #include <netinet/in.h> 66 #include <netinet/in_systm.h> 67 #include <netinet/in_var.h> 68 #include <netinet/ip.h> 69 #include <netinet/in_pcb.h> 70 #include <netinet/ip_var.h> 71 #include <netinet/ip_icmp.h> 72 #include <netinet/ip_options.h> 73 #include <machine/in_cksum.h> 74 #include <netinet/vinet.h> 75 #ifdef DEV_CARP 76 #include <netinet/ip_carp.h> 77 #endif 78 #ifdef IPSEC 79 #include <netinet/ip_ipsec.h> 80 #endif /* IPSEC */ 81 82 #include <sys/socketvar.h> 83 84 /* XXX: Temporary until ipfw_ether and ipfw_bridge are converted. */ 85 #include <netinet/ip_fw.h> 86 #include <netinet/ip_dummynet.h> 87 88 #include <security/mac/mac_framework.h> 89 90 #ifdef CTASSERT 91 CTASSERT(sizeof(struct ip) == 20); 92 #endif 93 94 #ifdef VIMAGE_GLOBALS 95 static int ipsendredirects; 96 static int ip_checkinterface; 97 static int ip_keepfaith; 98 static int ip_sendsourcequench; 99 int ip_defttl; 100 int ip_do_randomid; 101 int ipforwarding; 102 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 103 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 104 u_long in_ifaddrhmask; /* mask for hash table */ 105 struct ipstat ipstat; 106 static int ip_rsvp_on; 107 struct socket *ip_rsvpd; 108 int rsvp_on; 109 static struct ipqhead ipq[IPREASS_NHASH]; 110 static int maxnipq; /* Administrative limit on # reass queues. */ 111 static int maxfragsperpacket; 112 int ipstealth; 113 static int nipq; /* Total # of reass queues */ 114 #endif 115 116 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_FORWARDING, 117 forwarding, CTLFLAG_RW, ipforwarding, 0, 118 "Enable IP forwarding between interfaces"); 119 120 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_SENDREDIRECTS, 121 redirect, CTLFLAG_RW, ipsendredirects, 0, 122 "Enable sending IP redirects"); 123 124 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_DEFTTL, 125 ttl, CTLFLAG_RW, ip_defttl, 0, "Maximum TTL on IP packets"); 126 127 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_KEEPFAITH, 128 keepfaith, CTLFLAG_RW, ip_keepfaith, 0, 129 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 130 131 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, 132 sendsourcequench, CTLFLAG_RW, ip_sendsourcequench, 0, 133 "Enable the transmission of source quench packets"); 134 135 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, random_id, 136 CTLFLAG_RW, ip_do_randomid, 0, "Assign random ip_id values"); 137 138 /* 139 * XXX - Setting ip_checkinterface mostly implements the receive side of 140 * the Strong ES model described in RFC 1122, but since the routing table 141 * and transmit implementation do not implement the Strong ES model, 142 * setting this to 1 results in an odd hybrid. 143 * 144 * XXX - ip_checkinterface currently must be disabled if you use ipnat 145 * to translate the destination address to another local interface. 146 * 147 * XXX - ip_checkinterface must be disabled if you add IP aliases 148 * to the loopback interface instead of the interface where the 149 * packets for those addresses are received. 150 */ 151 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, 152 check_interface, CTLFLAG_RW, ip_checkinterface, 0, 153 "Verify packet arrives on correct interface"); 154 155 struct pfil_head inet_pfil_hook; /* Packet filter hooks */ 156 157 static struct ifqueue ipintrq; 158 static int ipqmaxlen = IFQ_MAXLEN; 159 160 extern struct domain inetdomain; 161 extern struct protosw inetsw[]; 162 u_char ip_protox[IPPROTO_MAX]; 163 164 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 165 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 166 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 167 &ipintrq.ifq_drops, 0, 168 "Number of packets dropped from the IP input queue"); 169 170 SYSCTL_V_STRUCT(V_NET, vnet_inet, _net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 171 ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 172 173 static uma_zone_t ipq_zone; 174 static struct mtx ipqlock; 175 176 #define IPQ_LOCK() mtx_lock(&ipqlock) 177 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 178 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 179 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 180 181 static void maxnipq_update(void); 182 static void ipq_zone_change(void *); 183 184 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, fragpackets, 185 CTLFLAG_RD, nipq, 0, 186 "Current number of IPv4 fragment reassembly queue entries"); 187 188 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, maxfragsperpacket, 189 CTLFLAG_RW, maxfragsperpacket, 0, 190 "Maximum number of IPv4 fragments allowed per packet"); 191 192 struct callout ipport_tick_callout; 193 194 #ifdef IPCTL_DEFMTU 195 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 196 &ip_mtu, 0, "Default MTU"); 197 #endif 198 199 #ifdef IPSTEALTH 200 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 201 ipstealth, 0, "IP stealth mode, no TTL decrementation on forwarding"); 202 #endif 203 204 /* 205 * ipfw_ether and ipfw_bridge hooks. 206 * XXX: Temporary until those are converted to pfil_hooks as well. 207 */ 208 ip_fw_chk_t *ip_fw_chk_ptr = NULL; 209 ip_dn_io_t *ip_dn_io_ptr = NULL; 210 int fw_one_pass = 1; 211 212 static void ip_freef(struct ipqhead *, struct ipq *); 213 214 /* 215 * IP initialization: fill in IP protocol switch table. 216 * All protocols not implemented in kernel go to raw IP protocol handler. 217 */ 218 void 219 ip_init(void) 220 { 221 INIT_VNET_INET(curvnet); 222 struct protosw *pr; 223 int i; 224 225 V_ipsendredirects = 1; /* XXX */ 226 V_ip_checkinterface = 0; 227 V_ip_keepfaith = 0; 228 V_ip_sendsourcequench = 0; 229 V_rsvp_on = 0; 230 V_ip_defttl = IPDEFTTL; 231 V_ip_do_randomid = 0; 232 V_ipforwarding = 0; 233 V_ipstealth = 0; 234 V_nipq = 0; /* Total # of reass queues */ 235 236 V_ipport_lowfirstauto = IPPORT_RESERVED - 1; /* 1023 */ 237 V_ipport_lowlastauto = IPPORT_RESERVEDSTART; /* 600 */ 238 V_ipport_firstauto = IPPORT_EPHEMERALFIRST; /* 10000 */ 239 V_ipport_lastauto = IPPORT_EPHEMERALLAST; /* 65535 */ 240 V_ipport_hifirstauto = IPPORT_HIFIRSTAUTO; /* 49152 */ 241 V_ipport_hilastauto = IPPORT_HILASTAUTO; /* 65535 */ 242 V_ipport_reservedhigh = IPPORT_RESERVED - 1; /* 1023 */ 243 V_ipport_reservedlow = 0; 244 V_ipport_randomized = 1; /* user controlled via sysctl */ 245 V_ipport_randomcps = 10; /* user controlled via sysctl */ 246 V_ipport_randomtime = 45; /* user controlled via sysctl */ 247 V_ipport_stoprandom = 0; /* toggled by ipport_tick */ 248 249 #ifdef NOTYET 250 /* XXX global static but not instantiated in this file */ 251 V_ipfastforward_active = 0; 252 V_subnetsarelocal = 0; 253 V_sameprefixcarponly = 0; 254 #endif 255 256 TAILQ_INIT(&V_in_ifaddrhead); 257 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask); 258 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 259 if (pr == NULL) 260 panic("ip_init: PF_INET not found"); 261 262 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 263 for (i = 0; i < IPPROTO_MAX; i++) 264 ip_protox[i] = pr - inetsw; 265 /* 266 * Cycle through IP protocols and put them into the appropriate place 267 * in ip_protox[]. 268 */ 269 for (pr = inetdomain.dom_protosw; 270 pr < inetdomain.dom_protoswNPROTOSW; pr++) 271 if (pr->pr_domain->dom_family == PF_INET && 272 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 273 /* Be careful to only index valid IP protocols. */ 274 if (pr->pr_protocol < IPPROTO_MAX) 275 ip_protox[pr->pr_protocol] = pr - inetsw; 276 } 277 278 /* Initialize packet filter hooks. */ 279 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 280 inet_pfil_hook.ph_af = AF_INET; 281 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 282 printf("%s: WARNING: unable to register pfil hook, " 283 "error %d\n", __func__, i); 284 285 /* Initialize IP reassembly queue. */ 286 IPQ_LOCK_INIT(); 287 for (i = 0; i < IPREASS_NHASH; i++) 288 TAILQ_INIT(&V_ipq[i]); 289 V_maxnipq = nmbclusters / 32; 290 V_maxfragsperpacket = 16; 291 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 292 NULL, UMA_ALIGN_PTR, 0); 293 maxnipq_update(); 294 295 /* Start ipport_tick. */ 296 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE); 297 ipport_tick(NULL); 298 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL, 299 SHUTDOWN_PRI_DEFAULT); 300 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, 301 NULL, EVENTHANDLER_PRI_ANY); 302 303 /* Initialize various other remaining things. */ 304 V_ip_id = time_second & 0xffff; 305 ipintrq.ifq_maxlen = ipqmaxlen; 306 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 307 netisr_register(NETISR_IP, ip_input, &ipintrq, 0); 308 } 309 310 void 311 ip_fini(void *xtp) 312 { 313 314 callout_stop(&ipport_tick_callout); 315 } 316 317 /* 318 * Ip input routine. Checksum and byte swap header. If fragmented 319 * try to reassemble. Process options. Pass to next level. 320 */ 321 void 322 ip_input(struct mbuf *m) 323 { 324 INIT_VNET_INET(curvnet); 325 struct ip *ip = NULL; 326 struct in_ifaddr *ia = NULL; 327 struct ifaddr *ifa; 328 int checkif, hlen = 0; 329 u_short sum; 330 int dchg = 0; /* dest changed after fw */ 331 struct in_addr odst; /* original dst address */ 332 333 M_ASSERTPKTHDR(m); 334 335 if (m->m_flags & M_FASTFWD_OURS) { 336 /* 337 * Firewall or NAT changed destination to local. 338 * We expect ip_len and ip_off to be in host byte order. 339 */ 340 m->m_flags &= ~M_FASTFWD_OURS; 341 /* Set up some basics that will be used later. */ 342 ip = mtod(m, struct ip *); 343 hlen = ip->ip_hl << 2; 344 goto ours; 345 } 346 347 V_ipstat.ips_total++; 348 349 if (m->m_pkthdr.len < sizeof(struct ip)) 350 goto tooshort; 351 352 if (m->m_len < sizeof (struct ip) && 353 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 354 V_ipstat.ips_toosmall++; 355 return; 356 } 357 ip = mtod(m, struct ip *); 358 359 if (ip->ip_v != IPVERSION) { 360 V_ipstat.ips_badvers++; 361 goto bad; 362 } 363 364 hlen = ip->ip_hl << 2; 365 if (hlen < sizeof(struct ip)) { /* minimum header length */ 366 V_ipstat.ips_badhlen++; 367 goto bad; 368 } 369 if (hlen > m->m_len) { 370 if ((m = m_pullup(m, hlen)) == NULL) { 371 V_ipstat.ips_badhlen++; 372 return; 373 } 374 ip = mtod(m, struct ip *); 375 } 376 377 /* 127/8 must not appear on wire - RFC1122 */ 378 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 379 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 380 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 381 V_ipstat.ips_badaddr++; 382 goto bad; 383 } 384 } 385 386 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 387 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 388 } else { 389 if (hlen == sizeof(struct ip)) { 390 sum = in_cksum_hdr(ip); 391 } else { 392 sum = in_cksum(m, hlen); 393 } 394 } 395 if (sum) { 396 V_ipstat.ips_badsum++; 397 goto bad; 398 } 399 400 #ifdef ALTQ 401 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 402 /* packet is dropped by traffic conditioner */ 403 return; 404 #endif 405 406 /* 407 * Convert fields to host representation. 408 */ 409 ip->ip_len = ntohs(ip->ip_len); 410 if (ip->ip_len < hlen) { 411 V_ipstat.ips_badlen++; 412 goto bad; 413 } 414 ip->ip_off = ntohs(ip->ip_off); 415 416 /* 417 * Check that the amount of data in the buffers 418 * is as at least much as the IP header would have us expect. 419 * Trim mbufs if longer than we expect. 420 * Drop packet if shorter than we expect. 421 */ 422 if (m->m_pkthdr.len < ip->ip_len) { 423 tooshort: 424 V_ipstat.ips_tooshort++; 425 goto bad; 426 } 427 if (m->m_pkthdr.len > ip->ip_len) { 428 if (m->m_len == m->m_pkthdr.len) { 429 m->m_len = ip->ip_len; 430 m->m_pkthdr.len = ip->ip_len; 431 } else 432 m_adj(m, ip->ip_len - m->m_pkthdr.len); 433 } 434 #ifdef IPSEC 435 /* 436 * Bypass packet filtering for packets from a tunnel (gif). 437 */ 438 if (ip_ipsec_filtertunnel(m)) 439 goto passin; 440 #endif /* IPSEC */ 441 442 /* 443 * Run through list of hooks for input packets. 444 * 445 * NB: Beware of the destination address changing (e.g. 446 * by NAT rewriting). When this happens, tell 447 * ip_forward to do the right thing. 448 */ 449 450 /* Jump over all PFIL processing if hooks are not active. */ 451 if (!PFIL_HOOKED(&inet_pfil_hook)) 452 goto passin; 453 454 odst = ip->ip_dst; 455 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 456 PFIL_IN, NULL) != 0) 457 return; 458 if (m == NULL) /* consumed by filter */ 459 return; 460 461 ip = mtod(m, struct ip *); 462 dchg = (odst.s_addr != ip->ip_dst.s_addr); 463 464 #ifdef IPFIREWALL_FORWARD 465 if (m->m_flags & M_FASTFWD_OURS) { 466 m->m_flags &= ~M_FASTFWD_OURS; 467 goto ours; 468 } 469 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 470 /* 471 * Directly ship on the packet. This allows to forward packets 472 * that were destined for us to some other directly connected 473 * host. 474 */ 475 ip_forward(m, dchg); 476 return; 477 } 478 #endif /* IPFIREWALL_FORWARD */ 479 480 passin: 481 /* 482 * Process options and, if not destined for us, 483 * ship it on. ip_dooptions returns 1 when an 484 * error was detected (causing an icmp message 485 * to be sent and the original packet to be freed). 486 */ 487 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 488 return; 489 490 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 491 * matter if it is destined to another node, or whether it is 492 * a multicast one, RSVP wants it! and prevents it from being forwarded 493 * anywhere else. Also checks if the rsvp daemon is running before 494 * grabbing the packet. 495 */ 496 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP) 497 goto ours; 498 499 /* 500 * Check our list of addresses, to see if the packet is for us. 501 * If we don't have any addresses, assume any unicast packet 502 * we receive might be for us (and let the upper layers deal 503 * with it). 504 */ 505 if (TAILQ_EMPTY(&V_in_ifaddrhead) && 506 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 507 goto ours; 508 509 /* 510 * Enable a consistency check between the destination address 511 * and the arrival interface for a unicast packet (the RFC 1122 512 * strong ES model) if IP forwarding is disabled and the packet 513 * is not locally generated and the packet is not subject to 514 * 'ipfw fwd'. 515 * 516 * XXX - Checking also should be disabled if the destination 517 * address is ipnat'ed to a different interface. 518 * 519 * XXX - Checking is incompatible with IP aliases added 520 * to the loopback interface instead of the interface where 521 * the packets are received. 522 * 523 * XXX - This is the case for carp vhost IPs as well so we 524 * insert a workaround. If the packet got here, we already 525 * checked with carp_iamatch() and carp_forus(). 526 */ 527 checkif = V_ip_checkinterface && (V_ipforwarding == 0) && 528 m->m_pkthdr.rcvif != NULL && 529 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 530 #ifdef DEV_CARP 531 !m->m_pkthdr.rcvif->if_carp && 532 #endif 533 (dchg == 0); 534 535 /* 536 * Check for exact addresses in the hash bucket. 537 */ 538 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 539 /* 540 * If the address matches, verify that the packet 541 * arrived via the correct interface if checking is 542 * enabled. 543 */ 544 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 545 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 546 goto ours; 547 } 548 /* 549 * Check for broadcast addresses. 550 * 551 * Only accept broadcast packets that arrive via the matching 552 * interface. Reception of forwarded directed broadcasts would 553 * be handled via ip_forward() and ether_output() with the loopback 554 * into the stack for SIMPLEX interfaces handled by ether_output(). 555 */ 556 if (m->m_pkthdr.rcvif != NULL && 557 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 558 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 559 if (ifa->ifa_addr->sa_family != AF_INET) 560 continue; 561 ia = ifatoia(ifa); 562 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 563 ip->ip_dst.s_addr) 564 goto ours; 565 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 566 goto ours; 567 #ifdef BOOTP_COMPAT 568 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 569 goto ours; 570 #endif 571 } 572 } 573 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */ 574 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) { 575 V_ipstat.ips_cantforward++; 576 m_freem(m); 577 return; 578 } 579 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 580 struct in_multi *inm; 581 if (V_ip_mrouter) { 582 /* 583 * If we are acting as a multicast router, all 584 * incoming multicast packets are passed to the 585 * kernel-level multicast forwarding function. 586 * The packet is returned (relatively) intact; if 587 * ip_mforward() returns a non-zero value, the packet 588 * must be discarded, else it may be accepted below. 589 */ 590 if (ip_mforward && 591 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 592 V_ipstat.ips_cantforward++; 593 m_freem(m); 594 return; 595 } 596 597 /* 598 * The process-level routing daemon needs to receive 599 * all multicast IGMP packets, whether or not this 600 * host belongs to their destination groups. 601 */ 602 if (ip->ip_p == IPPROTO_IGMP) 603 goto ours; 604 V_ipstat.ips_forward++; 605 } 606 /* 607 * See if we belong to the destination multicast group on the 608 * arrival interface. 609 */ 610 IN_MULTI_LOCK(); 611 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 612 IN_MULTI_UNLOCK(); 613 if (inm == NULL) { 614 V_ipstat.ips_notmember++; 615 m_freem(m); 616 return; 617 } 618 goto ours; 619 } 620 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 621 goto ours; 622 if (ip->ip_dst.s_addr == INADDR_ANY) 623 goto ours; 624 625 /* 626 * FAITH(Firewall Aided Internet Translator) 627 */ 628 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 629 if (V_ip_keepfaith) { 630 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 631 goto ours; 632 } 633 m_freem(m); 634 return; 635 } 636 637 /* 638 * Not for us; forward if possible and desirable. 639 */ 640 if (V_ipforwarding == 0) { 641 V_ipstat.ips_cantforward++; 642 m_freem(m); 643 } else { 644 #ifdef IPSEC 645 if (ip_ipsec_fwd(m)) 646 goto bad; 647 #endif /* IPSEC */ 648 ip_forward(m, dchg); 649 } 650 return; 651 652 ours: 653 #ifdef IPSTEALTH 654 /* 655 * IPSTEALTH: Process non-routing options only 656 * if the packet is destined for us. 657 */ 658 if (V_ipstealth && hlen > sizeof (struct ip) && 659 ip_dooptions(m, 1)) 660 return; 661 #endif /* IPSTEALTH */ 662 663 /* Count the packet in the ip address stats */ 664 if (ia != NULL) { 665 ia->ia_ifa.if_ipackets++; 666 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 667 } 668 669 /* 670 * Attempt reassembly; if it succeeds, proceed. 671 * ip_reass() will return a different mbuf. 672 */ 673 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 674 m = ip_reass(m); 675 if (m == NULL) 676 return; 677 ip = mtod(m, struct ip *); 678 /* Get the header length of the reassembled packet */ 679 hlen = ip->ip_hl << 2; 680 } 681 682 /* 683 * Further protocols expect the packet length to be w/o the 684 * IP header. 685 */ 686 ip->ip_len -= hlen; 687 688 #ifdef IPSEC 689 /* 690 * enforce IPsec policy checking if we are seeing last header. 691 * note that we do not visit this with protocols with pcb layer 692 * code - like udp/tcp/raw ip. 693 */ 694 if (ip_ipsec_input(m)) 695 goto bad; 696 #endif /* IPSEC */ 697 698 /* 699 * Switch out to protocol's input routine. 700 */ 701 V_ipstat.ips_delivered++; 702 703 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 704 return; 705 bad: 706 m_freem(m); 707 } 708 709 /* 710 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 711 * max has slightly different semantics than the sysctl, for historical 712 * reasons. 713 */ 714 static void 715 maxnipq_update(void) 716 { 717 INIT_VNET_INET(curvnet); 718 719 /* 720 * -1 for unlimited allocation. 721 */ 722 if (V_maxnipq < 0) 723 uma_zone_set_max(V_ipq_zone, 0); 724 /* 725 * Positive number for specific bound. 726 */ 727 if (V_maxnipq > 0) 728 uma_zone_set_max(V_ipq_zone, V_maxnipq); 729 /* 730 * Zero specifies no further fragment queue allocation -- set the 731 * bound very low, but rely on implementation elsewhere to actually 732 * prevent allocation and reclaim current queues. 733 */ 734 if (V_maxnipq == 0) 735 uma_zone_set_max(V_ipq_zone, 1); 736 } 737 738 static void 739 ipq_zone_change(void *tag) 740 { 741 INIT_VNET_INET(curvnet); 742 743 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) { 744 V_maxnipq = nmbclusters / 32; 745 maxnipq_update(); 746 } 747 } 748 749 static int 750 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 751 { 752 INIT_VNET_INET(curvnet); 753 int error, i; 754 755 i = V_maxnipq; 756 error = sysctl_handle_int(oidp, &i, 0, req); 757 if (error || !req->newptr) 758 return (error); 759 760 /* 761 * XXXRW: Might be a good idea to sanity check the argument and place 762 * an extreme upper bound. 763 */ 764 if (i < -1) 765 return (EINVAL); 766 V_maxnipq = i; 767 maxnipq_update(); 768 return (0); 769 } 770 771 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 772 NULL, 0, sysctl_maxnipq, "I", 773 "Maximum number of IPv4 fragment reassembly queue entries"); 774 775 /* 776 * Take incoming datagram fragment and try to reassemble it into 777 * whole datagram. If the argument is the first fragment or one 778 * in between the function will return NULL and store the mbuf 779 * in the fragment chain. If the argument is the last fragment 780 * the packet will be reassembled and the pointer to the new 781 * mbuf returned for further processing. Only m_tags attached 782 * to the first packet/fragment are preserved. 783 * The IP header is *NOT* adjusted out of iplen. 784 */ 785 struct mbuf * 786 ip_reass(struct mbuf *m) 787 { 788 INIT_VNET_INET(curvnet); 789 struct ip *ip; 790 struct mbuf *p, *q, *nq, *t; 791 struct ipq *fp = NULL; 792 struct ipqhead *head; 793 int i, hlen, next; 794 u_int8_t ecn, ecn0; 795 u_short hash; 796 797 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 798 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) { 799 V_ipstat.ips_fragments++; 800 V_ipstat.ips_fragdropped++; 801 m_freem(m); 802 return (NULL); 803 } 804 805 ip = mtod(m, struct ip *); 806 hlen = ip->ip_hl << 2; 807 808 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 809 head = &V_ipq[hash]; 810 IPQ_LOCK(); 811 812 /* 813 * Look for queue of fragments 814 * of this datagram. 815 */ 816 TAILQ_FOREACH(fp, head, ipq_list) 817 if (ip->ip_id == fp->ipq_id && 818 ip->ip_src.s_addr == fp->ipq_src.s_addr && 819 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 820 #ifdef MAC 821 mac_ipq_match(m, fp) && 822 #endif 823 ip->ip_p == fp->ipq_p) 824 goto found; 825 826 fp = NULL; 827 828 /* 829 * Attempt to trim the number of allocated fragment queues if it 830 * exceeds the administrative limit. 831 */ 832 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) { 833 /* 834 * drop something from the tail of the current queue 835 * before proceeding further 836 */ 837 struct ipq *q = TAILQ_LAST(head, ipqhead); 838 if (q == NULL) { /* gak */ 839 for (i = 0; i < IPREASS_NHASH; i++) { 840 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead); 841 if (r) { 842 V_ipstat.ips_fragtimeout += 843 r->ipq_nfrags; 844 ip_freef(&V_ipq[i], r); 845 break; 846 } 847 } 848 } else { 849 V_ipstat.ips_fragtimeout += q->ipq_nfrags; 850 ip_freef(head, q); 851 } 852 } 853 854 found: 855 /* 856 * Adjust ip_len to not reflect header, 857 * convert offset of this to bytes. 858 */ 859 ip->ip_len -= hlen; 860 if (ip->ip_off & IP_MF) { 861 /* 862 * Make sure that fragments have a data length 863 * that's a non-zero multiple of 8 bytes. 864 */ 865 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 866 V_ipstat.ips_toosmall++; /* XXX */ 867 goto dropfrag; 868 } 869 m->m_flags |= M_FRAG; 870 } else 871 m->m_flags &= ~M_FRAG; 872 ip->ip_off <<= 3; 873 874 875 /* 876 * Attempt reassembly; if it succeeds, proceed. 877 * ip_reass() will return a different mbuf. 878 */ 879 V_ipstat.ips_fragments++; 880 m->m_pkthdr.header = ip; 881 882 /* Previous ip_reass() started here. */ 883 /* 884 * Presence of header sizes in mbufs 885 * would confuse code below. 886 */ 887 m->m_data += hlen; 888 m->m_len -= hlen; 889 890 /* 891 * If first fragment to arrive, create a reassembly queue. 892 */ 893 if (fp == NULL) { 894 fp = uma_zalloc(V_ipq_zone, M_NOWAIT); 895 if (fp == NULL) 896 goto dropfrag; 897 #ifdef MAC 898 if (mac_ipq_init(fp, M_NOWAIT) != 0) { 899 uma_zfree(V_ipq_zone, fp); 900 fp = NULL; 901 goto dropfrag; 902 } 903 mac_ipq_create(m, fp); 904 #endif 905 TAILQ_INSERT_HEAD(head, fp, ipq_list); 906 V_nipq++; 907 fp->ipq_nfrags = 1; 908 fp->ipq_ttl = IPFRAGTTL; 909 fp->ipq_p = ip->ip_p; 910 fp->ipq_id = ip->ip_id; 911 fp->ipq_src = ip->ip_src; 912 fp->ipq_dst = ip->ip_dst; 913 fp->ipq_frags = m; 914 m->m_nextpkt = NULL; 915 goto done; 916 } else { 917 fp->ipq_nfrags++; 918 #ifdef MAC 919 mac_ipq_update(m, fp); 920 #endif 921 } 922 923 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 924 925 /* 926 * Handle ECN by comparing this segment with the first one; 927 * if CE is set, do not lose CE. 928 * drop if CE and not-ECT are mixed for the same packet. 929 */ 930 ecn = ip->ip_tos & IPTOS_ECN_MASK; 931 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 932 if (ecn == IPTOS_ECN_CE) { 933 if (ecn0 == IPTOS_ECN_NOTECT) 934 goto dropfrag; 935 if (ecn0 != IPTOS_ECN_CE) 936 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 937 } 938 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 939 goto dropfrag; 940 941 /* 942 * Find a segment which begins after this one does. 943 */ 944 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 945 if (GETIP(q)->ip_off > ip->ip_off) 946 break; 947 948 /* 949 * If there is a preceding segment, it may provide some of 950 * our data already. If so, drop the data from the incoming 951 * segment. If it provides all of our data, drop us, otherwise 952 * stick new segment in the proper place. 953 * 954 * If some of the data is dropped from the the preceding 955 * segment, then it's checksum is invalidated. 956 */ 957 if (p) { 958 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 959 if (i > 0) { 960 if (i >= ip->ip_len) 961 goto dropfrag; 962 m_adj(m, i); 963 m->m_pkthdr.csum_flags = 0; 964 ip->ip_off += i; 965 ip->ip_len -= i; 966 } 967 m->m_nextpkt = p->m_nextpkt; 968 p->m_nextpkt = m; 969 } else { 970 m->m_nextpkt = fp->ipq_frags; 971 fp->ipq_frags = m; 972 } 973 974 /* 975 * While we overlap succeeding segments trim them or, 976 * if they are completely covered, dequeue them. 977 */ 978 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 979 q = nq) { 980 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 981 if (i < GETIP(q)->ip_len) { 982 GETIP(q)->ip_len -= i; 983 GETIP(q)->ip_off += i; 984 m_adj(q, i); 985 q->m_pkthdr.csum_flags = 0; 986 break; 987 } 988 nq = q->m_nextpkt; 989 m->m_nextpkt = nq; 990 V_ipstat.ips_fragdropped++; 991 fp->ipq_nfrags--; 992 m_freem(q); 993 } 994 995 /* 996 * Check for complete reassembly and perform frag per packet 997 * limiting. 998 * 999 * Frag limiting is performed here so that the nth frag has 1000 * a chance to complete the packet before we drop the packet. 1001 * As a result, n+1 frags are actually allowed per packet, but 1002 * only n will ever be stored. (n = maxfragsperpacket.) 1003 * 1004 */ 1005 next = 0; 1006 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1007 if (GETIP(q)->ip_off != next) { 1008 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1009 V_ipstat.ips_fragdropped += fp->ipq_nfrags; 1010 ip_freef(head, fp); 1011 } 1012 goto done; 1013 } 1014 next += GETIP(q)->ip_len; 1015 } 1016 /* Make sure the last packet didn't have the IP_MF flag */ 1017 if (p->m_flags & M_FRAG) { 1018 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1019 V_ipstat.ips_fragdropped += fp->ipq_nfrags; 1020 ip_freef(head, fp); 1021 } 1022 goto done; 1023 } 1024 1025 /* 1026 * Reassembly is complete. Make sure the packet is a sane size. 1027 */ 1028 q = fp->ipq_frags; 1029 ip = GETIP(q); 1030 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1031 V_ipstat.ips_toolong++; 1032 V_ipstat.ips_fragdropped += fp->ipq_nfrags; 1033 ip_freef(head, fp); 1034 goto done; 1035 } 1036 1037 /* 1038 * Concatenate fragments. 1039 */ 1040 m = q; 1041 t = m->m_next; 1042 m->m_next = NULL; 1043 m_cat(m, t); 1044 nq = q->m_nextpkt; 1045 q->m_nextpkt = NULL; 1046 for (q = nq; q != NULL; q = nq) { 1047 nq = q->m_nextpkt; 1048 q->m_nextpkt = NULL; 1049 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1050 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1051 m_cat(m, q); 1052 } 1053 /* 1054 * In order to do checksumming faster we do 'end-around carry' here 1055 * (and not in for{} loop), though it implies we are not going to 1056 * reassemble more than 64k fragments. 1057 */ 1058 m->m_pkthdr.csum_data = 1059 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1060 #ifdef MAC 1061 mac_ipq_reassemble(fp, m); 1062 mac_ipq_destroy(fp); 1063 #endif 1064 1065 /* 1066 * Create header for new ip packet by modifying header of first 1067 * packet; dequeue and discard fragment reassembly header. 1068 * Make header visible. 1069 */ 1070 ip->ip_len = (ip->ip_hl << 2) + next; 1071 ip->ip_src = fp->ipq_src; 1072 ip->ip_dst = fp->ipq_dst; 1073 TAILQ_REMOVE(head, fp, ipq_list); 1074 V_nipq--; 1075 uma_zfree(V_ipq_zone, fp); 1076 m->m_len += (ip->ip_hl << 2); 1077 m->m_data -= (ip->ip_hl << 2); 1078 /* some debugging cruft by sklower, below, will go away soon */ 1079 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1080 m_fixhdr(m); 1081 V_ipstat.ips_reassembled++; 1082 IPQ_UNLOCK(); 1083 return (m); 1084 1085 dropfrag: 1086 V_ipstat.ips_fragdropped++; 1087 if (fp != NULL) 1088 fp->ipq_nfrags--; 1089 m_freem(m); 1090 done: 1091 IPQ_UNLOCK(); 1092 return (NULL); 1093 1094 #undef GETIP 1095 } 1096 1097 /* 1098 * Free a fragment reassembly header and all 1099 * associated datagrams. 1100 */ 1101 static void 1102 ip_freef(struct ipqhead *fhp, struct ipq *fp) 1103 { 1104 INIT_VNET_INET(curvnet); 1105 struct mbuf *q; 1106 1107 IPQ_LOCK_ASSERT(); 1108 1109 while (fp->ipq_frags) { 1110 q = fp->ipq_frags; 1111 fp->ipq_frags = q->m_nextpkt; 1112 m_freem(q); 1113 } 1114 TAILQ_REMOVE(fhp, fp, ipq_list); 1115 uma_zfree(V_ipq_zone, fp); 1116 V_nipq--; 1117 } 1118 1119 /* 1120 * IP timer processing; 1121 * if a timer expires on a reassembly 1122 * queue, discard it. 1123 */ 1124 void 1125 ip_slowtimo(void) 1126 { 1127 VNET_ITERATOR_DECL(vnet_iter); 1128 struct ipq *fp; 1129 int i; 1130 1131 IPQ_LOCK(); 1132 VNET_LIST_RLOCK(); 1133 VNET_FOREACH(vnet_iter) { 1134 CURVNET_SET(vnet_iter); 1135 INIT_VNET_INET(vnet_iter); 1136 for (i = 0; i < IPREASS_NHASH; i++) { 1137 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) { 1138 struct ipq *fpp; 1139 1140 fpp = fp; 1141 fp = TAILQ_NEXT(fp, ipq_list); 1142 if(--fpp->ipq_ttl == 0) { 1143 V_ipstat.ips_fragtimeout += 1144 fpp->ipq_nfrags; 1145 ip_freef(&V_ipq[i], fpp); 1146 } 1147 } 1148 } 1149 /* 1150 * If we are over the maximum number of fragments 1151 * (due to the limit being lowered), drain off 1152 * enough to get down to the new limit. 1153 */ 1154 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) { 1155 for (i = 0; i < IPREASS_NHASH; i++) { 1156 while (V_nipq > V_maxnipq && 1157 !TAILQ_EMPTY(&V_ipq[i])) { 1158 V_ipstat.ips_fragdropped += 1159 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags; 1160 ip_freef(&V_ipq[i], 1161 TAILQ_FIRST(&V_ipq[i])); 1162 } 1163 } 1164 } 1165 CURVNET_RESTORE(); 1166 } 1167 VNET_LIST_RUNLOCK(); 1168 IPQ_UNLOCK(); 1169 } 1170 1171 /* 1172 * Drain off all datagram fragments. 1173 */ 1174 void 1175 ip_drain(void) 1176 { 1177 VNET_ITERATOR_DECL(vnet_iter); 1178 int i; 1179 1180 IPQ_LOCK(); 1181 VNET_LIST_RLOCK(); 1182 VNET_FOREACH(vnet_iter) { 1183 CURVNET_SET(vnet_iter); 1184 INIT_VNET_INET(vnet_iter); 1185 for (i = 0; i < IPREASS_NHASH; i++) { 1186 while(!TAILQ_EMPTY(&V_ipq[i])) { 1187 V_ipstat.ips_fragdropped += 1188 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags; 1189 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i])); 1190 } 1191 } 1192 CURVNET_RESTORE(); 1193 } 1194 VNET_LIST_RUNLOCK(); 1195 IPQ_UNLOCK(); 1196 in_rtqdrain(); 1197 } 1198 1199 /* 1200 * The protocol to be inserted into ip_protox[] must be already registered 1201 * in inetsw[], either statically or through pf_proto_register(). 1202 */ 1203 int 1204 ipproto_register(u_char ipproto) 1205 { 1206 struct protosw *pr; 1207 1208 /* Sanity checks. */ 1209 if (ipproto == 0) 1210 return (EPROTONOSUPPORT); 1211 1212 /* 1213 * The protocol slot must not be occupied by another protocol 1214 * already. An index pointing to IPPROTO_RAW is unused. 1215 */ 1216 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1217 if (pr == NULL) 1218 return (EPFNOSUPPORT); 1219 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1220 return (EEXIST); 1221 1222 /* Find the protocol position in inetsw[] and set the index. */ 1223 for (pr = inetdomain.dom_protosw; 1224 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1225 if (pr->pr_domain->dom_family == PF_INET && 1226 pr->pr_protocol && pr->pr_protocol == ipproto) { 1227 /* Be careful to only index valid IP protocols. */ 1228 if (pr->pr_protocol < IPPROTO_MAX) { 1229 ip_protox[pr->pr_protocol] = pr - inetsw; 1230 return (0); 1231 } else 1232 return (EINVAL); 1233 } 1234 } 1235 return (EPROTONOSUPPORT); 1236 } 1237 1238 int 1239 ipproto_unregister(u_char ipproto) 1240 { 1241 struct protosw *pr; 1242 1243 /* Sanity checks. */ 1244 if (ipproto == 0) 1245 return (EPROTONOSUPPORT); 1246 1247 /* Check if the protocol was indeed registered. */ 1248 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1249 if (pr == NULL) 1250 return (EPFNOSUPPORT); 1251 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1252 return (ENOENT); 1253 1254 /* Reset the protocol slot to IPPROTO_RAW. */ 1255 ip_protox[ipproto] = pr - inetsw; 1256 return (0); 1257 } 1258 1259 /* 1260 * Given address of next destination (final or next hop), 1261 * return internet address info of interface to be used to get there. 1262 */ 1263 struct in_ifaddr * 1264 ip_rtaddr(struct in_addr dst, u_int fibnum) 1265 { 1266 struct route sro; 1267 struct sockaddr_in *sin; 1268 struct in_ifaddr *ifa; 1269 1270 bzero(&sro, sizeof(sro)); 1271 sin = (struct sockaddr_in *)&sro.ro_dst; 1272 sin->sin_family = AF_INET; 1273 sin->sin_len = sizeof(*sin); 1274 sin->sin_addr = dst; 1275 in_rtalloc_ign(&sro, RTF_CLONING, fibnum); 1276 1277 if (sro.ro_rt == NULL) 1278 return (NULL); 1279 1280 ifa = ifatoia(sro.ro_rt->rt_ifa); 1281 RTFREE(sro.ro_rt); 1282 return (ifa); 1283 } 1284 1285 u_char inetctlerrmap[PRC_NCMDS] = { 1286 0, 0, 0, 0, 1287 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1288 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1289 EMSGSIZE, EHOSTUNREACH, 0, 0, 1290 0, 0, EHOSTUNREACH, 0, 1291 ENOPROTOOPT, ECONNREFUSED 1292 }; 1293 1294 /* 1295 * Forward a packet. If some error occurs return the sender 1296 * an icmp packet. Note we can't always generate a meaningful 1297 * icmp message because icmp doesn't have a large enough repertoire 1298 * of codes and types. 1299 * 1300 * If not forwarding, just drop the packet. This could be confusing 1301 * if ipforwarding was zero but some routing protocol was advancing 1302 * us as a gateway to somewhere. However, we must let the routing 1303 * protocol deal with that. 1304 * 1305 * The srcrt parameter indicates whether the packet is being forwarded 1306 * via a source route. 1307 */ 1308 void 1309 ip_forward(struct mbuf *m, int srcrt) 1310 { 1311 INIT_VNET_INET(curvnet); 1312 struct ip *ip = mtod(m, struct ip *); 1313 struct in_ifaddr *ia = NULL; 1314 struct mbuf *mcopy; 1315 struct in_addr dest; 1316 struct route ro; 1317 int error, type = 0, code = 0, mtu = 0; 1318 1319 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1320 V_ipstat.ips_cantforward++; 1321 m_freem(m); 1322 return; 1323 } 1324 #ifdef IPSTEALTH 1325 if (!V_ipstealth) { 1326 #endif 1327 if (ip->ip_ttl <= IPTTLDEC) { 1328 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1329 0, 0); 1330 return; 1331 } 1332 #ifdef IPSTEALTH 1333 } 1334 #endif 1335 1336 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m)); 1337 if (!srcrt && ia == NULL) { 1338 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1339 return; 1340 } 1341 1342 /* 1343 * Save the IP header and at most 8 bytes of the payload, 1344 * in case we need to generate an ICMP message to the src. 1345 * 1346 * XXX this can be optimized a lot by saving the data in a local 1347 * buffer on the stack (72 bytes at most), and only allocating the 1348 * mbuf if really necessary. The vast majority of the packets 1349 * are forwarded without having to send an ICMP back (either 1350 * because unnecessary, or because rate limited), so we are 1351 * really we are wasting a lot of work here. 1352 * 1353 * We don't use m_copy() because it might return a reference 1354 * to a shared cluster. Both this function and ip_output() 1355 * assume exclusive access to the IP header in `m', so any 1356 * data in a cluster may change before we reach icmp_error(). 1357 */ 1358 MGETHDR(mcopy, M_DONTWAIT, m->m_type); 1359 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1360 /* 1361 * It's probably ok if the pkthdr dup fails (because 1362 * the deep copy of the tag chain failed), but for now 1363 * be conservative and just discard the copy since 1364 * code below may some day want the tags. 1365 */ 1366 m_free(mcopy); 1367 mcopy = NULL; 1368 } 1369 if (mcopy != NULL) { 1370 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy)); 1371 mcopy->m_pkthdr.len = mcopy->m_len; 1372 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1373 } 1374 1375 #ifdef IPSTEALTH 1376 if (!V_ipstealth) { 1377 #endif 1378 ip->ip_ttl -= IPTTLDEC; 1379 #ifdef IPSTEALTH 1380 } 1381 #endif 1382 1383 /* 1384 * If forwarding packet using same interface that it came in on, 1385 * perhaps should send a redirect to sender to shortcut a hop. 1386 * Only send redirect if source is sending directly to us, 1387 * and if packet was not source routed (or has any options). 1388 * Also, don't send redirect if forwarding using a default route 1389 * or a route modified by a redirect. 1390 */ 1391 dest.s_addr = 0; 1392 if (!srcrt && V_ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1393 struct sockaddr_in *sin; 1394 struct rtentry *rt; 1395 1396 bzero(&ro, sizeof(ro)); 1397 sin = (struct sockaddr_in *)&ro.ro_dst; 1398 sin->sin_family = AF_INET; 1399 sin->sin_len = sizeof(*sin); 1400 sin->sin_addr = ip->ip_dst; 1401 in_rtalloc_ign(&ro, RTF_CLONING, M_GETFIB(m)); 1402 1403 rt = ro.ro_rt; 1404 1405 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1406 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1407 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1408 u_long src = ntohl(ip->ip_src.s_addr); 1409 1410 if (RTA(rt) && 1411 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1412 if (rt->rt_flags & RTF_GATEWAY) 1413 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1414 else 1415 dest.s_addr = ip->ip_dst.s_addr; 1416 /* Router requirements says to only send host redirects */ 1417 type = ICMP_REDIRECT; 1418 code = ICMP_REDIRECT_HOST; 1419 } 1420 } 1421 if (rt) 1422 RTFREE(rt); 1423 } 1424 1425 /* 1426 * Try to cache the route MTU from ip_output so we can consider it for 1427 * the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191. 1428 */ 1429 bzero(&ro, sizeof(ro)); 1430 1431 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL); 1432 1433 if (error == EMSGSIZE && ro.ro_rt) 1434 mtu = ro.ro_rt->rt_rmx.rmx_mtu; 1435 if (ro.ro_rt) 1436 RTFREE(ro.ro_rt); 1437 1438 if (error) 1439 V_ipstat.ips_cantforward++; 1440 else { 1441 V_ipstat.ips_forward++; 1442 if (type) 1443 V_ipstat.ips_redirectsent++; 1444 else { 1445 if (mcopy) 1446 m_freem(mcopy); 1447 return; 1448 } 1449 } 1450 if (mcopy == NULL) 1451 return; 1452 1453 switch (error) { 1454 1455 case 0: /* forwarded, but need redirect */ 1456 /* type, code set above */ 1457 break; 1458 1459 case ENETUNREACH: /* shouldn't happen, checked above */ 1460 case EHOSTUNREACH: 1461 case ENETDOWN: 1462 case EHOSTDOWN: 1463 default: 1464 type = ICMP_UNREACH; 1465 code = ICMP_UNREACH_HOST; 1466 break; 1467 1468 case EMSGSIZE: 1469 type = ICMP_UNREACH; 1470 code = ICMP_UNREACH_NEEDFRAG; 1471 1472 #ifdef IPSEC 1473 /* 1474 * If IPsec is configured for this path, 1475 * override any possibly mtu value set by ip_output. 1476 */ 1477 mtu = ip_ipsec_mtu(m, mtu); 1478 #endif /* IPSEC */ 1479 /* 1480 * If the MTU was set before make sure we are below the 1481 * interface MTU. 1482 * If the MTU wasn't set before use the interface mtu or 1483 * fall back to the next smaller mtu step compared to the 1484 * current packet size. 1485 */ 1486 if (mtu != 0) { 1487 if (ia != NULL) 1488 mtu = min(mtu, ia->ia_ifp->if_mtu); 1489 } else { 1490 if (ia != NULL) 1491 mtu = ia->ia_ifp->if_mtu; 1492 else 1493 mtu = ip_next_mtu(ip->ip_len, 0); 1494 } 1495 V_ipstat.ips_cantfrag++; 1496 break; 1497 1498 case ENOBUFS: 1499 /* 1500 * A router should not generate ICMP_SOURCEQUENCH as 1501 * required in RFC1812 Requirements for IP Version 4 Routers. 1502 * Source quench could be a big problem under DoS attacks, 1503 * or if the underlying interface is rate-limited. 1504 * Those who need source quench packets may re-enable them 1505 * via the net.inet.ip.sendsourcequench sysctl. 1506 */ 1507 if (V_ip_sendsourcequench == 0) { 1508 m_freem(mcopy); 1509 return; 1510 } else { 1511 type = ICMP_SOURCEQUENCH; 1512 code = 0; 1513 } 1514 break; 1515 1516 case EACCES: /* ipfw denied packet */ 1517 m_freem(mcopy); 1518 return; 1519 } 1520 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1521 } 1522 1523 void 1524 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1525 struct mbuf *m) 1526 { 1527 INIT_VNET_NET(inp->inp_vnet); 1528 1529 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1530 struct bintime bt; 1531 1532 bintime(&bt); 1533 if (inp->inp_socket->so_options & SO_BINTIME) { 1534 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 1535 SCM_BINTIME, SOL_SOCKET); 1536 if (*mp) 1537 mp = &(*mp)->m_next; 1538 } 1539 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1540 struct timeval tv; 1541 1542 bintime2timeval(&bt, &tv); 1543 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1544 SCM_TIMESTAMP, SOL_SOCKET); 1545 if (*mp) 1546 mp = &(*mp)->m_next; 1547 } 1548 } 1549 if (inp->inp_flags & INP_RECVDSTADDR) { 1550 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1551 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1552 if (*mp) 1553 mp = &(*mp)->m_next; 1554 } 1555 if (inp->inp_flags & INP_RECVTTL) { 1556 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1557 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1558 if (*mp) 1559 mp = &(*mp)->m_next; 1560 } 1561 #ifdef notyet 1562 /* XXX 1563 * Moving these out of udp_input() made them even more broken 1564 * than they already were. 1565 */ 1566 /* options were tossed already */ 1567 if (inp->inp_flags & INP_RECVOPTS) { 1568 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1569 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1570 if (*mp) 1571 mp = &(*mp)->m_next; 1572 } 1573 /* ip_srcroute doesn't do what we want here, need to fix */ 1574 if (inp->inp_flags & INP_RECVRETOPTS) { 1575 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1576 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1577 if (*mp) 1578 mp = &(*mp)->m_next; 1579 } 1580 #endif 1581 if (inp->inp_flags & INP_RECVIF) { 1582 struct ifnet *ifp; 1583 struct sdlbuf { 1584 struct sockaddr_dl sdl; 1585 u_char pad[32]; 1586 } sdlbuf; 1587 struct sockaddr_dl *sdp; 1588 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1589 1590 if (((ifp = m->m_pkthdr.rcvif)) 1591 && ( ifp->if_index && (ifp->if_index <= V_if_index))) { 1592 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1593 /* 1594 * Change our mind and don't try copy. 1595 */ 1596 if ((sdp->sdl_family != AF_LINK) 1597 || (sdp->sdl_len > sizeof(sdlbuf))) { 1598 goto makedummy; 1599 } 1600 bcopy(sdp, sdl2, sdp->sdl_len); 1601 } else { 1602 makedummy: 1603 sdl2->sdl_len 1604 = offsetof(struct sockaddr_dl, sdl_data[0]); 1605 sdl2->sdl_family = AF_LINK; 1606 sdl2->sdl_index = 0; 1607 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1608 } 1609 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1610 IP_RECVIF, IPPROTO_IP); 1611 if (*mp) 1612 mp = &(*mp)->m_next; 1613 } 1614 } 1615 1616 /* 1617 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the 1618 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on 1619 * locking. This code remains in ip_input.c as ip_mroute.c is optionally 1620 * compiled. 1621 */ 1622 int 1623 ip_rsvp_init(struct socket *so) 1624 { 1625 INIT_VNET_INET(so->so_vnet); 1626 1627 if (so->so_type != SOCK_RAW || 1628 so->so_proto->pr_protocol != IPPROTO_RSVP) 1629 return EOPNOTSUPP; 1630 1631 if (V_ip_rsvpd != NULL) 1632 return EADDRINUSE; 1633 1634 V_ip_rsvpd = so; 1635 /* 1636 * This may seem silly, but we need to be sure we don't over-increment 1637 * the RSVP counter, in case something slips up. 1638 */ 1639 if (!V_ip_rsvp_on) { 1640 V_ip_rsvp_on = 1; 1641 V_rsvp_on++; 1642 } 1643 1644 return 0; 1645 } 1646 1647 int 1648 ip_rsvp_done(void) 1649 { 1650 INIT_VNET_INET(curvnet); 1651 1652 V_ip_rsvpd = NULL; 1653 /* 1654 * This may seem silly, but we need to be sure we don't over-decrement 1655 * the RSVP counter, in case something slips up. 1656 */ 1657 if (V_ip_rsvp_on) { 1658 V_ip_rsvp_on = 0; 1659 V_rsvp_on--; 1660 } 1661 return 0; 1662 } 1663 1664 void 1665 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1666 { 1667 INIT_VNET_INET(curvnet); 1668 1669 if (rsvp_input_p) { /* call the real one if loaded */ 1670 rsvp_input_p(m, off); 1671 return; 1672 } 1673 1674 /* Can still get packets with rsvp_on = 0 if there is a local member 1675 * of the group to which the RSVP packet is addressed. But in this 1676 * case we want to throw the packet away. 1677 */ 1678 1679 if (!V_rsvp_on) { 1680 m_freem(m); 1681 return; 1682 } 1683 1684 if (V_ip_rsvpd != NULL) { 1685 rip_input(m, off); 1686 return; 1687 } 1688 /* Drop the packet */ 1689 m_freem(m); 1690 } 1691