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_route.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/lock.h> 53 #include <sys/rwlock.h> 54 #include <sys/syslog.h> 55 #include <sys/sysctl.h> 56 #include <sys/vimage.h> 57 58 #include <net/pfil.h> 59 #include <net/if.h> 60 #include <net/if_types.h> 61 #include <net/if_var.h> 62 #include <net/if_dl.h> 63 #include <net/route.h> 64 #include <net/netisr.h> 65 #include <net/vnet.h> 66 #include <net/flowtable.h> 67 68 #include <netinet/in.h> 69 #include <netinet/in_systm.h> 70 #include <netinet/in_var.h> 71 #include <netinet/ip.h> 72 #include <netinet/in_pcb.h> 73 #include <netinet/ip_var.h> 74 #include <netinet/ip_icmp.h> 75 #include <netinet/ip_options.h> 76 #include <machine/in_cksum.h> 77 #include <netinet/vinet.h> 78 #ifdef DEV_CARP 79 #include <netinet/ip_carp.h> 80 #endif 81 #ifdef IPSEC 82 #include <netinet/ip_ipsec.h> 83 #endif /* IPSEC */ 84 85 #include <sys/socketvar.h> 86 87 #include <security/mac/mac_framework.h> 88 89 #ifdef CTASSERT 90 CTASSERT(sizeof(struct ip) == 20); 91 #endif 92 93 #ifndef VIMAGE 94 #ifndef VIMAGE_GLOBALS 95 struct vnet_inet vnet_inet_0; 96 #endif 97 #endif 98 99 #ifdef VIMAGE_GLOBALS 100 static int ipsendredirects; 101 static int ip_checkinterface; 102 static int ip_keepfaith; 103 static int ip_sendsourcequench; 104 int ip_defttl; 105 int ip_do_randomid; 106 int ipforwarding; 107 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 108 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 109 u_long in_ifaddrhmask; /* mask for hash table */ 110 struct ipstat ipstat; 111 static int ip_rsvp_on; 112 struct socket *ip_rsvpd; 113 int rsvp_on; 114 static struct ipqhead ipq[IPREASS_NHASH]; 115 static int maxnipq; /* Administrative limit on # reass queues. */ 116 static int maxfragsperpacket; 117 int ipstealth; 118 static int nipq; /* Total # of reass queues */ 119 #endif 120 121 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_FORWARDING, 122 forwarding, CTLFLAG_RW, ipforwarding, 0, 123 "Enable IP forwarding between interfaces"); 124 125 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_SENDREDIRECTS, 126 redirect, CTLFLAG_RW, ipsendredirects, 0, 127 "Enable sending IP redirects"); 128 129 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_DEFTTL, 130 ttl, CTLFLAG_RW, ip_defttl, 0, "Maximum TTL on IP packets"); 131 132 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_KEEPFAITH, 133 keepfaith, CTLFLAG_RW, ip_keepfaith, 0, 134 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 135 136 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, 137 sendsourcequench, CTLFLAG_RW, ip_sendsourcequench, 0, 138 "Enable the transmission of source quench packets"); 139 140 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, random_id, 141 CTLFLAG_RW, ip_do_randomid, 0, "Assign random ip_id values"); 142 143 /* 144 * XXX - Setting ip_checkinterface mostly implements the receive side of 145 * the Strong ES model described in RFC 1122, but since the routing table 146 * and transmit implementation do not implement the Strong ES model, 147 * setting this to 1 results in an odd hybrid. 148 * 149 * XXX - ip_checkinterface currently must be disabled if you use ipnat 150 * to translate the destination address to another local interface. 151 * 152 * XXX - ip_checkinterface must be disabled if you add IP aliases 153 * to the loopback interface instead of the interface where the 154 * packets for those addresses are received. 155 */ 156 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, 157 check_interface, CTLFLAG_RW, ip_checkinterface, 0, 158 "Verify packet arrives on correct interface"); 159 160 struct pfil_head inet_pfil_hook; /* Packet filter hooks */ 161 162 static struct netisr_handler ip_nh = { 163 .nh_name = "ip", 164 .nh_handler = ip_input, 165 .nh_proto = NETISR_IP, 166 .nh_policy = NETISR_POLICY_FLOW, 167 }; 168 169 extern struct domain inetdomain; 170 extern struct protosw inetsw[]; 171 u_char ip_protox[IPPROTO_MAX]; 172 173 174 SYSCTL_V_STRUCT(V_NET, vnet_inet, _net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 175 ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 176 177 #ifdef VIMAGE_GLOBALS 178 static uma_zone_t ipq_zone; 179 #endif 180 static struct mtx ipqlock; 181 182 #define IPQ_LOCK() mtx_lock(&ipqlock) 183 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 184 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 185 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 186 187 static void maxnipq_update(void); 188 static void ipq_zone_change(void *); 189 190 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, fragpackets, 191 CTLFLAG_RD, nipq, 0, 192 "Current number of IPv4 fragment reassembly queue entries"); 193 194 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, maxfragsperpacket, 195 CTLFLAG_RW, maxfragsperpacket, 0, 196 "Maximum number of IPv4 fragments allowed per packet"); 197 198 struct callout ipport_tick_callout; 199 200 #ifdef IPCTL_DEFMTU 201 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 202 &ip_mtu, 0, "Default MTU"); 203 #endif 204 205 #ifdef IPSTEALTH 206 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 207 ipstealth, 0, "IP stealth mode, no TTL decrementation on forwarding"); 208 #endif 209 #ifdef FLOWTABLE 210 #ifdef VIMAGE_GLOBALS 211 static int ip_output_flowtable_size; 212 struct flowtable *ip_ft; 213 #endif 214 SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, OID_AUTO, output_flowtable_size, 215 CTLFLAG_RDTUN, ip_output_flowtable_size, 2048, 216 "number of entries in the per-cpu output flow caches"); 217 #endif 218 219 #ifdef VIMAGE_GLOBALS 220 int fw_one_pass; 221 #endif 222 223 static void ip_freef(struct ipqhead *, struct ipq *); 224 225 #ifndef VIMAGE_GLOBALS 226 static void vnet_inet_register(void); 227 228 static const vnet_modinfo_t vnet_inet_modinfo = { 229 .vmi_id = VNET_MOD_INET, 230 .vmi_name = "inet", 231 .vmi_size = sizeof(struct vnet_inet) 232 }; 233 234 static void vnet_inet_register() 235 { 236 237 vnet_mod_register(&vnet_inet_modinfo); 238 } 239 240 SYSINIT(inet, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST, vnet_inet_register, 0); 241 #endif 242 243 static int 244 sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS) 245 { 246 int error, qlimit; 247 248 netisr_getqlimit(&ip_nh, &qlimit); 249 error = sysctl_handle_int(oidp, &qlimit, 0, req); 250 if (error || !req->newptr) 251 return (error); 252 if (qlimit < 1) 253 return (EINVAL); 254 return (netisr_setqlimit(&ip_nh, qlimit)); 255 } 256 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, 257 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I", 258 "Maximum size of the IP input queue"); 259 260 static int 261 sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS) 262 { 263 u_int64_t qdrops_long; 264 int error, qdrops; 265 266 netisr_getqdrops(&ip_nh, &qdrops_long); 267 qdrops = qdrops_long; 268 error = sysctl_handle_int(oidp, &qdrops, 0, req); 269 if (error || !req->newptr) 270 return (error); 271 if (qdrops != 0) 272 return (EINVAL); 273 netisr_clearqdrops(&ip_nh); 274 return (0); 275 } 276 277 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, 278 CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I", 279 "Number of packets dropped from the IP input queue"); 280 281 /* 282 * IP initialization: fill in IP protocol switch table. 283 * All protocols not implemented in kernel go to raw IP protocol handler. 284 */ 285 void 286 ip_init(void) 287 { 288 INIT_VNET_INET(curvnet); 289 struct protosw *pr; 290 int i; 291 292 V_ipsendredirects = 1; /* XXX */ 293 V_ip_checkinterface = 0; 294 V_ip_keepfaith = 0; 295 V_ip_sendsourcequench = 0; 296 V_rsvp_on = 0; 297 V_ip_defttl = IPDEFTTL; 298 V_ip_do_randomid = 0; 299 V_ip_id = time_second & 0xffff; 300 V_ipforwarding = 0; 301 V_ipstealth = 0; 302 V_nipq = 0; /* Total # of reass queues */ 303 304 V_ipport_lowfirstauto = IPPORT_RESERVED - 1; /* 1023 */ 305 V_ipport_lowlastauto = IPPORT_RESERVEDSTART; /* 600 */ 306 V_ipport_firstauto = IPPORT_EPHEMERALFIRST; /* 10000 */ 307 V_ipport_lastauto = IPPORT_EPHEMERALLAST; /* 65535 */ 308 V_ipport_hifirstauto = IPPORT_HIFIRSTAUTO; /* 49152 */ 309 V_ipport_hilastauto = IPPORT_HILASTAUTO; /* 65535 */ 310 V_ipport_reservedhigh = IPPORT_RESERVED - 1; /* 1023 */ 311 V_ipport_reservedlow = 0; 312 V_ipport_randomized = 1; /* user controlled via sysctl */ 313 V_ipport_randomcps = 10; /* user controlled via sysctl */ 314 V_ipport_randomtime = 45; /* user controlled via sysctl */ 315 V_ipport_stoprandom = 0; /* toggled by ipport_tick */ 316 317 V_fw_one_pass = 1; 318 319 #ifdef NOTYET 320 /* XXX global static but not instantiated in this file */ 321 V_ipfastforward_active = 0; 322 V_subnetsarelocal = 0; 323 V_sameprefixcarponly = 0; 324 #endif 325 326 TAILQ_INIT(&V_in_ifaddrhead); 327 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask); 328 329 /* Initialize IP reassembly queue. */ 330 for (i = 0; i < IPREASS_NHASH; i++) 331 TAILQ_INIT(&V_ipq[i]); 332 V_maxnipq = nmbclusters / 32; 333 V_maxfragsperpacket = 16; 334 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 335 NULL, UMA_ALIGN_PTR, 0); 336 maxnipq_update(); 337 338 #ifdef FLOWTABLE 339 V_ip_output_flowtable_size = 2048; 340 TUNABLE_INT_FETCH("net.inet.ip.output_flowtable_size", 341 &V_ip_output_flowtable_size); 342 V_ip_ft = flowtable_alloc(V_ip_output_flowtable_size, FL_PCPU); 343 #endif 344 345 /* Skip initialization of globals for non-default instances. */ 346 if (!IS_DEFAULT_VNET(curvnet)) 347 return; 348 349 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 350 if (pr == NULL) 351 panic("ip_init: PF_INET not found"); 352 353 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 354 for (i = 0; i < IPPROTO_MAX; i++) 355 ip_protox[i] = pr - inetsw; 356 /* 357 * Cycle through IP protocols and put them into the appropriate place 358 * in ip_protox[]. 359 */ 360 for (pr = inetdomain.dom_protosw; 361 pr < inetdomain.dom_protoswNPROTOSW; pr++) 362 if (pr->pr_domain->dom_family == PF_INET && 363 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 364 /* Be careful to only index valid IP protocols. */ 365 if (pr->pr_protocol < IPPROTO_MAX) 366 ip_protox[pr->pr_protocol] = pr - inetsw; 367 } 368 369 /* Initialize packet filter hooks. */ 370 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 371 inet_pfil_hook.ph_af = AF_INET; 372 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 373 printf("%s: WARNING: unable to register pfil hook, " 374 "error %d\n", __func__, i); 375 376 /* Start ipport_tick. */ 377 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE); 378 callout_reset(&ipport_tick_callout, 1, ipport_tick, NULL); 379 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL, 380 SHUTDOWN_PRI_DEFAULT); 381 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, 382 NULL, EVENTHANDLER_PRI_ANY); 383 384 /* Initialize various other remaining things. */ 385 IPQ_LOCK_INIT(); 386 netisr_register(&ip_nh); 387 } 388 389 void 390 ip_fini(void *xtp) 391 { 392 393 callout_stop(&ipport_tick_callout); 394 } 395 396 /* 397 * Ip input routine. Checksum and byte swap header. If fragmented 398 * try to reassemble. Process options. Pass to next level. 399 */ 400 void 401 ip_input(struct mbuf *m) 402 { 403 INIT_VNET_INET(curvnet); 404 struct ip *ip = NULL; 405 struct in_ifaddr *ia = NULL; 406 struct ifaddr *ifa; 407 struct ifnet *ifp; 408 int checkif, hlen = 0; 409 u_short sum; 410 int dchg = 0; /* dest changed after fw */ 411 struct in_addr odst; /* original dst address */ 412 413 M_ASSERTPKTHDR(m); 414 415 if (m->m_flags & M_FASTFWD_OURS) { 416 /* 417 * Firewall or NAT changed destination to local. 418 * We expect ip_len and ip_off to be in host byte order. 419 */ 420 m->m_flags &= ~M_FASTFWD_OURS; 421 /* Set up some basics that will be used later. */ 422 ip = mtod(m, struct ip *); 423 hlen = ip->ip_hl << 2; 424 goto ours; 425 } 426 427 IPSTAT_INC(ips_total); 428 429 if (m->m_pkthdr.len < sizeof(struct ip)) 430 goto tooshort; 431 432 if (m->m_len < sizeof (struct ip) && 433 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 434 IPSTAT_INC(ips_toosmall); 435 return; 436 } 437 ip = mtod(m, struct ip *); 438 439 if (ip->ip_v != IPVERSION) { 440 IPSTAT_INC(ips_badvers); 441 goto bad; 442 } 443 444 hlen = ip->ip_hl << 2; 445 if (hlen < sizeof(struct ip)) { /* minimum header length */ 446 IPSTAT_INC(ips_badhlen); 447 goto bad; 448 } 449 if (hlen > m->m_len) { 450 if ((m = m_pullup(m, hlen)) == NULL) { 451 IPSTAT_INC(ips_badhlen); 452 return; 453 } 454 ip = mtod(m, struct ip *); 455 } 456 457 /* 127/8 must not appear on wire - RFC1122 */ 458 ifp = m->m_pkthdr.rcvif; 459 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 460 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 461 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 462 IPSTAT_INC(ips_badaddr); 463 goto bad; 464 } 465 } 466 467 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 468 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 469 } else { 470 if (hlen == sizeof(struct ip)) { 471 sum = in_cksum_hdr(ip); 472 } else { 473 sum = in_cksum(m, hlen); 474 } 475 } 476 if (sum) { 477 IPSTAT_INC(ips_badsum); 478 goto bad; 479 } 480 481 #ifdef ALTQ 482 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 483 /* packet is dropped by traffic conditioner */ 484 return; 485 #endif 486 487 /* 488 * Convert fields to host representation. 489 */ 490 ip->ip_len = ntohs(ip->ip_len); 491 if (ip->ip_len < hlen) { 492 IPSTAT_INC(ips_badlen); 493 goto bad; 494 } 495 ip->ip_off = ntohs(ip->ip_off); 496 497 /* 498 * Check that the amount of data in the buffers 499 * is as at least much as the IP header would have us expect. 500 * Trim mbufs if longer than we expect. 501 * Drop packet if shorter than we expect. 502 */ 503 if (m->m_pkthdr.len < ip->ip_len) { 504 tooshort: 505 IPSTAT_INC(ips_tooshort); 506 goto bad; 507 } 508 if (m->m_pkthdr.len > ip->ip_len) { 509 if (m->m_len == m->m_pkthdr.len) { 510 m->m_len = ip->ip_len; 511 m->m_pkthdr.len = ip->ip_len; 512 } else 513 m_adj(m, ip->ip_len - m->m_pkthdr.len); 514 } 515 #ifdef IPSEC 516 /* 517 * Bypass packet filtering for packets from a tunnel (gif). 518 */ 519 if (ip_ipsec_filtertunnel(m)) 520 goto passin; 521 #endif /* IPSEC */ 522 523 /* 524 * Run through list of hooks for input packets. 525 * 526 * NB: Beware of the destination address changing (e.g. 527 * by NAT rewriting). When this happens, tell 528 * ip_forward to do the right thing. 529 */ 530 531 /* Jump over all PFIL processing if hooks are not active. */ 532 if (!PFIL_HOOKED(&inet_pfil_hook)) 533 goto passin; 534 535 odst = ip->ip_dst; 536 if (pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0) 537 return; 538 if (m == NULL) /* consumed by filter */ 539 return; 540 541 ip = mtod(m, struct ip *); 542 dchg = (odst.s_addr != ip->ip_dst.s_addr); 543 ifp = m->m_pkthdr.rcvif; 544 545 #ifdef IPFIREWALL_FORWARD 546 if (m->m_flags & M_FASTFWD_OURS) { 547 m->m_flags &= ~M_FASTFWD_OURS; 548 goto ours; 549 } 550 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 551 /* 552 * Directly ship on the packet. This allows to forward packets 553 * that were destined for us to some other directly connected 554 * host. 555 */ 556 ip_forward(m, dchg); 557 return; 558 } 559 #endif /* IPFIREWALL_FORWARD */ 560 561 passin: 562 /* 563 * Process options and, if not destined for us, 564 * ship it on. ip_dooptions returns 1 when an 565 * error was detected (causing an icmp message 566 * to be sent and the original packet to be freed). 567 */ 568 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 569 return; 570 571 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 572 * matter if it is destined to another node, or whether it is 573 * a multicast one, RSVP wants it! and prevents it from being forwarded 574 * anywhere else. Also checks if the rsvp daemon is running before 575 * grabbing the packet. 576 */ 577 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP) 578 goto ours; 579 580 /* 581 * Check our list of addresses, to see if the packet is for us. 582 * If we don't have any addresses, assume any unicast packet 583 * we receive might be for us (and let the upper layers deal 584 * with it). 585 */ 586 if (TAILQ_EMPTY(&V_in_ifaddrhead) && 587 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 588 goto ours; 589 590 /* 591 * Enable a consistency check between the destination address 592 * and the arrival interface for a unicast packet (the RFC 1122 593 * strong ES model) if IP forwarding is disabled and the packet 594 * is not locally generated and the packet is not subject to 595 * 'ipfw fwd'. 596 * 597 * XXX - Checking also should be disabled if the destination 598 * address is ipnat'ed to a different interface. 599 * 600 * XXX - Checking is incompatible with IP aliases added 601 * to the loopback interface instead of the interface where 602 * the packets are received. 603 * 604 * XXX - This is the case for carp vhost IPs as well so we 605 * insert a workaround. If the packet got here, we already 606 * checked with carp_iamatch() and carp_forus(). 607 */ 608 checkif = V_ip_checkinterface && (V_ipforwarding == 0) && 609 ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) && 610 #ifdef DEV_CARP 611 !ifp->if_carp && 612 #endif 613 (dchg == 0); 614 615 /* 616 * Check for exact addresses in the hash bucket. 617 */ 618 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 619 /* 620 * If the address matches, verify that the packet 621 * arrived via the correct interface if checking is 622 * enabled. 623 */ 624 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 625 (!checkif || ia->ia_ifp == ifp)) 626 goto ours; 627 } 628 /* 629 * Check for broadcast addresses. 630 * 631 * Only accept broadcast packets that arrive via the matching 632 * interface. Reception of forwarded directed broadcasts would 633 * be handled via ip_forward() and ether_output() with the loopback 634 * into the stack for SIMPLEX interfaces handled by ether_output(). 635 */ 636 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) { 637 IF_ADDR_LOCK(ifp); 638 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 639 if (ifa->ifa_addr->sa_family != AF_INET) 640 continue; 641 ia = ifatoia(ifa); 642 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 643 ip->ip_dst.s_addr) { 644 IF_ADDR_UNLOCK(ifp); 645 goto ours; 646 } 647 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) { 648 IF_ADDR_UNLOCK(ifp); 649 goto ours; 650 } 651 #ifdef BOOTP_COMPAT 652 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) { 653 IF_ADDR_UNLOCK(ifp); 654 goto ours; 655 } 656 #endif 657 } 658 IF_ADDR_UNLOCK(ifp); 659 } 660 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */ 661 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) { 662 IPSTAT_INC(ips_cantforward); 663 m_freem(m); 664 return; 665 } 666 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 667 if (V_ip_mrouter) { 668 /* 669 * If we are acting as a multicast router, all 670 * incoming multicast packets are passed to the 671 * kernel-level multicast forwarding function. 672 * The packet is returned (relatively) intact; if 673 * ip_mforward() returns a non-zero value, the packet 674 * must be discarded, else it may be accepted below. 675 */ 676 if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) { 677 IPSTAT_INC(ips_cantforward); 678 m_freem(m); 679 return; 680 } 681 682 /* 683 * The process-level routing daemon needs to receive 684 * all multicast IGMP packets, whether or not this 685 * host belongs to their destination groups. 686 */ 687 if (ip->ip_p == IPPROTO_IGMP) 688 goto ours; 689 IPSTAT_INC(ips_forward); 690 } 691 /* 692 * Assume the packet is for us, to avoid prematurely taking 693 * a lock on the in_multi hash. Protocols must perform 694 * their own filtering and update statistics accordingly. 695 */ 696 goto ours; 697 } 698 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 699 goto ours; 700 if (ip->ip_dst.s_addr == INADDR_ANY) 701 goto ours; 702 703 /* 704 * FAITH(Firewall Aided Internet Translator) 705 */ 706 if (ifp && ifp->if_type == IFT_FAITH) { 707 if (V_ip_keepfaith) { 708 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 709 goto ours; 710 } 711 m_freem(m); 712 return; 713 } 714 715 /* 716 * Not for us; forward if possible and desirable. 717 */ 718 if (V_ipforwarding == 0) { 719 IPSTAT_INC(ips_cantforward); 720 m_freem(m); 721 } else { 722 #ifdef IPSEC 723 if (ip_ipsec_fwd(m)) 724 goto bad; 725 #endif /* IPSEC */ 726 ip_forward(m, dchg); 727 } 728 return; 729 730 ours: 731 #ifdef IPSTEALTH 732 /* 733 * IPSTEALTH: Process non-routing options only 734 * if the packet is destined for us. 735 */ 736 if (V_ipstealth && hlen > sizeof (struct ip) && 737 ip_dooptions(m, 1)) 738 return; 739 #endif /* IPSTEALTH */ 740 741 /* Count the packet in the ip address stats */ 742 if (ia != NULL) { 743 ia->ia_ifa.if_ipackets++; 744 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 745 } 746 747 /* 748 * Attempt reassembly; if it succeeds, proceed. 749 * ip_reass() will return a different mbuf. 750 */ 751 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 752 m = ip_reass(m); 753 if (m == NULL) 754 return; 755 ip = mtod(m, struct ip *); 756 /* Get the header length of the reassembled packet */ 757 hlen = ip->ip_hl << 2; 758 } 759 760 /* 761 * Further protocols expect the packet length to be w/o the 762 * IP header. 763 */ 764 ip->ip_len -= hlen; 765 766 #ifdef IPSEC 767 /* 768 * enforce IPsec policy checking if we are seeing last header. 769 * note that we do not visit this with protocols with pcb layer 770 * code - like udp/tcp/raw ip. 771 */ 772 if (ip_ipsec_input(m)) 773 goto bad; 774 #endif /* IPSEC */ 775 776 /* 777 * Switch out to protocol's input routine. 778 */ 779 IPSTAT_INC(ips_delivered); 780 781 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 782 return; 783 bad: 784 m_freem(m); 785 } 786 787 /* 788 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 789 * max has slightly different semantics than the sysctl, for historical 790 * reasons. 791 */ 792 static void 793 maxnipq_update(void) 794 { 795 INIT_VNET_INET(curvnet); 796 797 /* 798 * -1 for unlimited allocation. 799 */ 800 if (V_maxnipq < 0) 801 uma_zone_set_max(V_ipq_zone, 0); 802 /* 803 * Positive number for specific bound. 804 */ 805 if (V_maxnipq > 0) 806 uma_zone_set_max(V_ipq_zone, V_maxnipq); 807 /* 808 * Zero specifies no further fragment queue allocation -- set the 809 * bound very low, but rely on implementation elsewhere to actually 810 * prevent allocation and reclaim current queues. 811 */ 812 if (V_maxnipq == 0) 813 uma_zone_set_max(V_ipq_zone, 1); 814 } 815 816 static void 817 ipq_zone_change(void *tag) 818 { 819 INIT_VNET_INET(curvnet); 820 821 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) { 822 V_maxnipq = nmbclusters / 32; 823 maxnipq_update(); 824 } 825 } 826 827 static int 828 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 829 { 830 INIT_VNET_INET(curvnet); 831 int error, i; 832 833 i = V_maxnipq; 834 error = sysctl_handle_int(oidp, &i, 0, req); 835 if (error || !req->newptr) 836 return (error); 837 838 /* 839 * XXXRW: Might be a good idea to sanity check the argument and place 840 * an extreme upper bound. 841 */ 842 if (i < -1) 843 return (EINVAL); 844 V_maxnipq = i; 845 maxnipq_update(); 846 return (0); 847 } 848 849 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 850 NULL, 0, sysctl_maxnipq, "I", 851 "Maximum number of IPv4 fragment reassembly queue entries"); 852 853 /* 854 * Take incoming datagram fragment and try to reassemble it into 855 * whole datagram. If the argument is the first fragment or one 856 * in between the function will return NULL and store the mbuf 857 * in the fragment chain. If the argument is the last fragment 858 * the packet will be reassembled and the pointer to the new 859 * mbuf returned for further processing. Only m_tags attached 860 * to the first packet/fragment are preserved. 861 * The IP header is *NOT* adjusted out of iplen. 862 */ 863 struct mbuf * 864 ip_reass(struct mbuf *m) 865 { 866 INIT_VNET_INET(curvnet); 867 struct ip *ip; 868 struct mbuf *p, *q, *nq, *t; 869 struct ipq *fp = NULL; 870 struct ipqhead *head; 871 int i, hlen, next; 872 u_int8_t ecn, ecn0; 873 u_short hash; 874 875 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 876 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) { 877 IPSTAT_INC(ips_fragments); 878 IPSTAT_INC(ips_fragdropped); 879 m_freem(m); 880 return (NULL); 881 } 882 883 ip = mtod(m, struct ip *); 884 hlen = ip->ip_hl << 2; 885 886 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 887 head = &V_ipq[hash]; 888 IPQ_LOCK(); 889 890 /* 891 * Look for queue of fragments 892 * of this datagram. 893 */ 894 TAILQ_FOREACH(fp, head, ipq_list) 895 if (ip->ip_id == fp->ipq_id && 896 ip->ip_src.s_addr == fp->ipq_src.s_addr && 897 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 898 #ifdef MAC 899 mac_ipq_match(m, fp) && 900 #endif 901 ip->ip_p == fp->ipq_p) 902 goto found; 903 904 fp = NULL; 905 906 /* 907 * Attempt to trim the number of allocated fragment queues if it 908 * exceeds the administrative limit. 909 */ 910 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) { 911 /* 912 * drop something from the tail of the current queue 913 * before proceeding further 914 */ 915 struct ipq *q = TAILQ_LAST(head, ipqhead); 916 if (q == NULL) { /* gak */ 917 for (i = 0; i < IPREASS_NHASH; i++) { 918 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead); 919 if (r) { 920 IPSTAT_ADD(ips_fragtimeout, 921 r->ipq_nfrags); 922 ip_freef(&V_ipq[i], r); 923 break; 924 } 925 } 926 } else { 927 IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags); 928 ip_freef(head, q); 929 } 930 } 931 932 found: 933 /* 934 * Adjust ip_len to not reflect header, 935 * convert offset of this to bytes. 936 */ 937 ip->ip_len -= hlen; 938 if (ip->ip_off & IP_MF) { 939 /* 940 * Make sure that fragments have a data length 941 * that's a non-zero multiple of 8 bytes. 942 */ 943 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 944 IPSTAT_INC(ips_toosmall); /* XXX */ 945 goto dropfrag; 946 } 947 m->m_flags |= M_FRAG; 948 } else 949 m->m_flags &= ~M_FRAG; 950 ip->ip_off <<= 3; 951 952 953 /* 954 * Attempt reassembly; if it succeeds, proceed. 955 * ip_reass() will return a different mbuf. 956 */ 957 IPSTAT_INC(ips_fragments); 958 m->m_pkthdr.header = ip; 959 960 /* Previous ip_reass() started here. */ 961 /* 962 * Presence of header sizes in mbufs 963 * would confuse code below. 964 */ 965 m->m_data += hlen; 966 m->m_len -= hlen; 967 968 /* 969 * If first fragment to arrive, create a reassembly queue. 970 */ 971 if (fp == NULL) { 972 fp = uma_zalloc(V_ipq_zone, M_NOWAIT); 973 if (fp == NULL) 974 goto dropfrag; 975 #ifdef MAC 976 if (mac_ipq_init(fp, M_NOWAIT) != 0) { 977 uma_zfree(V_ipq_zone, fp); 978 fp = NULL; 979 goto dropfrag; 980 } 981 mac_ipq_create(m, fp); 982 #endif 983 TAILQ_INSERT_HEAD(head, fp, ipq_list); 984 V_nipq++; 985 fp->ipq_nfrags = 1; 986 fp->ipq_ttl = IPFRAGTTL; 987 fp->ipq_p = ip->ip_p; 988 fp->ipq_id = ip->ip_id; 989 fp->ipq_src = ip->ip_src; 990 fp->ipq_dst = ip->ip_dst; 991 fp->ipq_frags = m; 992 m->m_nextpkt = NULL; 993 goto done; 994 } else { 995 fp->ipq_nfrags++; 996 #ifdef MAC 997 mac_ipq_update(m, fp); 998 #endif 999 } 1000 1001 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1002 1003 /* 1004 * Handle ECN by comparing this segment with the first one; 1005 * if CE is set, do not lose CE. 1006 * drop if CE and not-ECT are mixed for the same packet. 1007 */ 1008 ecn = ip->ip_tos & IPTOS_ECN_MASK; 1009 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 1010 if (ecn == IPTOS_ECN_CE) { 1011 if (ecn0 == IPTOS_ECN_NOTECT) 1012 goto dropfrag; 1013 if (ecn0 != IPTOS_ECN_CE) 1014 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 1015 } 1016 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 1017 goto dropfrag; 1018 1019 /* 1020 * Find a segment which begins after this one does. 1021 */ 1022 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1023 if (GETIP(q)->ip_off > ip->ip_off) 1024 break; 1025 1026 /* 1027 * If there is a preceding segment, it may provide some of 1028 * our data already. If so, drop the data from the incoming 1029 * segment. If it provides all of our data, drop us, otherwise 1030 * stick new segment in the proper place. 1031 * 1032 * If some of the data is dropped from the the preceding 1033 * segment, then it's checksum is invalidated. 1034 */ 1035 if (p) { 1036 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1037 if (i > 0) { 1038 if (i >= ip->ip_len) 1039 goto dropfrag; 1040 m_adj(m, i); 1041 m->m_pkthdr.csum_flags = 0; 1042 ip->ip_off += i; 1043 ip->ip_len -= i; 1044 } 1045 m->m_nextpkt = p->m_nextpkt; 1046 p->m_nextpkt = m; 1047 } else { 1048 m->m_nextpkt = fp->ipq_frags; 1049 fp->ipq_frags = m; 1050 } 1051 1052 /* 1053 * While we overlap succeeding segments trim them or, 1054 * if they are completely covered, dequeue them. 1055 */ 1056 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1057 q = nq) { 1058 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1059 if (i < GETIP(q)->ip_len) { 1060 GETIP(q)->ip_len -= i; 1061 GETIP(q)->ip_off += i; 1062 m_adj(q, i); 1063 q->m_pkthdr.csum_flags = 0; 1064 break; 1065 } 1066 nq = q->m_nextpkt; 1067 m->m_nextpkt = nq; 1068 IPSTAT_INC(ips_fragdropped); 1069 fp->ipq_nfrags--; 1070 m_freem(q); 1071 } 1072 1073 /* 1074 * Check for complete reassembly and perform frag per packet 1075 * limiting. 1076 * 1077 * Frag limiting is performed here so that the nth frag has 1078 * a chance to complete the packet before we drop the packet. 1079 * As a result, n+1 frags are actually allowed per packet, but 1080 * only n will ever be stored. (n = maxfragsperpacket.) 1081 * 1082 */ 1083 next = 0; 1084 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1085 if (GETIP(q)->ip_off != next) { 1086 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1087 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1088 ip_freef(head, fp); 1089 } 1090 goto done; 1091 } 1092 next += GETIP(q)->ip_len; 1093 } 1094 /* Make sure the last packet didn't have the IP_MF flag */ 1095 if (p->m_flags & M_FRAG) { 1096 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1097 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1098 ip_freef(head, fp); 1099 } 1100 goto done; 1101 } 1102 1103 /* 1104 * Reassembly is complete. Make sure the packet is a sane size. 1105 */ 1106 q = fp->ipq_frags; 1107 ip = GETIP(q); 1108 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1109 IPSTAT_INC(ips_toolong); 1110 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1111 ip_freef(head, fp); 1112 goto done; 1113 } 1114 1115 /* 1116 * Concatenate fragments. 1117 */ 1118 m = q; 1119 t = m->m_next; 1120 m->m_next = NULL; 1121 m_cat(m, t); 1122 nq = q->m_nextpkt; 1123 q->m_nextpkt = NULL; 1124 for (q = nq; q != NULL; q = nq) { 1125 nq = q->m_nextpkt; 1126 q->m_nextpkt = NULL; 1127 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1128 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1129 m_cat(m, q); 1130 } 1131 /* 1132 * In order to do checksumming faster we do 'end-around carry' here 1133 * (and not in for{} loop), though it implies we are not going to 1134 * reassemble more than 64k fragments. 1135 */ 1136 m->m_pkthdr.csum_data = 1137 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1138 #ifdef MAC 1139 mac_ipq_reassemble(fp, m); 1140 mac_ipq_destroy(fp); 1141 #endif 1142 1143 /* 1144 * Create header for new ip packet by modifying header of first 1145 * packet; dequeue and discard fragment reassembly header. 1146 * Make header visible. 1147 */ 1148 ip->ip_len = (ip->ip_hl << 2) + next; 1149 ip->ip_src = fp->ipq_src; 1150 ip->ip_dst = fp->ipq_dst; 1151 TAILQ_REMOVE(head, fp, ipq_list); 1152 V_nipq--; 1153 uma_zfree(V_ipq_zone, fp); 1154 m->m_len += (ip->ip_hl << 2); 1155 m->m_data -= (ip->ip_hl << 2); 1156 /* some debugging cruft by sklower, below, will go away soon */ 1157 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1158 m_fixhdr(m); 1159 IPSTAT_INC(ips_reassembled); 1160 IPQ_UNLOCK(); 1161 return (m); 1162 1163 dropfrag: 1164 IPSTAT_INC(ips_fragdropped); 1165 if (fp != NULL) 1166 fp->ipq_nfrags--; 1167 m_freem(m); 1168 done: 1169 IPQ_UNLOCK(); 1170 return (NULL); 1171 1172 #undef GETIP 1173 } 1174 1175 /* 1176 * Free a fragment reassembly header and all 1177 * associated datagrams. 1178 */ 1179 static void 1180 ip_freef(struct ipqhead *fhp, struct ipq *fp) 1181 { 1182 INIT_VNET_INET(curvnet); 1183 struct mbuf *q; 1184 1185 IPQ_LOCK_ASSERT(); 1186 1187 while (fp->ipq_frags) { 1188 q = fp->ipq_frags; 1189 fp->ipq_frags = q->m_nextpkt; 1190 m_freem(q); 1191 } 1192 TAILQ_REMOVE(fhp, fp, ipq_list); 1193 uma_zfree(V_ipq_zone, fp); 1194 V_nipq--; 1195 } 1196 1197 /* 1198 * IP timer processing; 1199 * if a timer expires on a reassembly 1200 * queue, discard it. 1201 */ 1202 void 1203 ip_slowtimo(void) 1204 { 1205 VNET_ITERATOR_DECL(vnet_iter); 1206 struct ipq *fp; 1207 int i; 1208 1209 IPQ_LOCK(); 1210 VNET_LIST_RLOCK(); 1211 VNET_FOREACH(vnet_iter) { 1212 CURVNET_SET(vnet_iter); 1213 INIT_VNET_INET(vnet_iter); 1214 for (i = 0; i < IPREASS_NHASH; i++) { 1215 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) { 1216 struct ipq *fpp; 1217 1218 fpp = fp; 1219 fp = TAILQ_NEXT(fp, ipq_list); 1220 if(--fpp->ipq_ttl == 0) { 1221 IPSTAT_ADD(ips_fragtimeout, 1222 fpp->ipq_nfrags); 1223 ip_freef(&V_ipq[i], fpp); 1224 } 1225 } 1226 } 1227 /* 1228 * If we are over the maximum number of fragments 1229 * (due to the limit being lowered), drain off 1230 * enough to get down to the new limit. 1231 */ 1232 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) { 1233 for (i = 0; i < IPREASS_NHASH; i++) { 1234 while (V_nipq > V_maxnipq && 1235 !TAILQ_EMPTY(&V_ipq[i])) { 1236 IPSTAT_ADD(ips_fragdropped, 1237 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1238 ip_freef(&V_ipq[i], 1239 TAILQ_FIRST(&V_ipq[i])); 1240 } 1241 } 1242 } 1243 CURVNET_RESTORE(); 1244 } 1245 VNET_LIST_RUNLOCK(); 1246 IPQ_UNLOCK(); 1247 } 1248 1249 /* 1250 * Drain off all datagram fragments. 1251 */ 1252 void 1253 ip_drain(void) 1254 { 1255 VNET_ITERATOR_DECL(vnet_iter); 1256 int i; 1257 1258 IPQ_LOCK(); 1259 VNET_LIST_RLOCK(); 1260 VNET_FOREACH(vnet_iter) { 1261 CURVNET_SET(vnet_iter); 1262 INIT_VNET_INET(vnet_iter); 1263 for (i = 0; i < IPREASS_NHASH; i++) { 1264 while(!TAILQ_EMPTY(&V_ipq[i])) { 1265 IPSTAT_ADD(ips_fragdropped, 1266 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1267 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i])); 1268 } 1269 } 1270 CURVNET_RESTORE(); 1271 } 1272 VNET_LIST_RUNLOCK(); 1273 IPQ_UNLOCK(); 1274 in_rtqdrain(); 1275 } 1276 1277 /* 1278 * The protocol to be inserted into ip_protox[] must be already registered 1279 * in inetsw[], either statically or through pf_proto_register(). 1280 */ 1281 int 1282 ipproto_register(u_char ipproto) 1283 { 1284 struct protosw *pr; 1285 1286 /* Sanity checks. */ 1287 if (ipproto == 0) 1288 return (EPROTONOSUPPORT); 1289 1290 /* 1291 * The protocol slot must not be occupied by another protocol 1292 * already. An index pointing to IPPROTO_RAW is unused. 1293 */ 1294 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1295 if (pr == NULL) 1296 return (EPFNOSUPPORT); 1297 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1298 return (EEXIST); 1299 1300 /* Find the protocol position in inetsw[] and set the index. */ 1301 for (pr = inetdomain.dom_protosw; 1302 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1303 if (pr->pr_domain->dom_family == PF_INET && 1304 pr->pr_protocol && pr->pr_protocol == ipproto) { 1305 /* Be careful to only index valid IP protocols. */ 1306 if (pr->pr_protocol < IPPROTO_MAX) { 1307 ip_protox[pr->pr_protocol] = pr - inetsw; 1308 return (0); 1309 } else 1310 return (EINVAL); 1311 } 1312 } 1313 return (EPROTONOSUPPORT); 1314 } 1315 1316 int 1317 ipproto_unregister(u_char ipproto) 1318 { 1319 struct protosw *pr; 1320 1321 /* Sanity checks. */ 1322 if (ipproto == 0) 1323 return (EPROTONOSUPPORT); 1324 1325 /* Check if the protocol was indeed registered. */ 1326 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1327 if (pr == NULL) 1328 return (EPFNOSUPPORT); 1329 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1330 return (ENOENT); 1331 1332 /* Reset the protocol slot to IPPROTO_RAW. */ 1333 ip_protox[ipproto] = pr - inetsw; 1334 return (0); 1335 } 1336 1337 /* 1338 * Given address of next destination (final or next hop), 1339 * return internet address info of interface to be used to get there. 1340 */ 1341 struct in_ifaddr * 1342 ip_rtaddr(struct in_addr dst, u_int fibnum) 1343 { 1344 struct route sro; 1345 struct sockaddr_in *sin; 1346 struct in_ifaddr *ifa; 1347 1348 bzero(&sro, sizeof(sro)); 1349 sin = (struct sockaddr_in *)&sro.ro_dst; 1350 sin->sin_family = AF_INET; 1351 sin->sin_len = sizeof(*sin); 1352 sin->sin_addr = dst; 1353 in_rtalloc_ign(&sro, 0, fibnum); 1354 1355 if (sro.ro_rt == NULL) 1356 return (NULL); 1357 1358 ifa = ifatoia(sro.ro_rt->rt_ifa); 1359 RTFREE(sro.ro_rt); 1360 return (ifa); 1361 } 1362 1363 u_char inetctlerrmap[PRC_NCMDS] = { 1364 0, 0, 0, 0, 1365 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1366 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1367 EMSGSIZE, EHOSTUNREACH, 0, 0, 1368 0, 0, EHOSTUNREACH, 0, 1369 ENOPROTOOPT, ECONNREFUSED 1370 }; 1371 1372 /* 1373 * Forward a packet. If some error occurs return the sender 1374 * an icmp packet. Note we can't always generate a meaningful 1375 * icmp message because icmp doesn't have a large enough repertoire 1376 * of codes and types. 1377 * 1378 * If not forwarding, just drop the packet. This could be confusing 1379 * if ipforwarding was zero but some routing protocol was advancing 1380 * us as a gateway to somewhere. However, we must let the routing 1381 * protocol deal with that. 1382 * 1383 * The srcrt parameter indicates whether the packet is being forwarded 1384 * via a source route. 1385 */ 1386 void 1387 ip_forward(struct mbuf *m, int srcrt) 1388 { 1389 INIT_VNET_INET(curvnet); 1390 struct ip *ip = mtod(m, struct ip *); 1391 struct in_ifaddr *ia; 1392 struct mbuf *mcopy; 1393 struct in_addr dest; 1394 struct route ro; 1395 int error, type = 0, code = 0, mtu = 0; 1396 1397 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1398 IPSTAT_INC(ips_cantforward); 1399 m_freem(m); 1400 return; 1401 } 1402 #ifdef IPSTEALTH 1403 if (!V_ipstealth) { 1404 #endif 1405 if (ip->ip_ttl <= IPTTLDEC) { 1406 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1407 0, 0); 1408 return; 1409 } 1410 #ifdef IPSTEALTH 1411 } 1412 #endif 1413 1414 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m)); 1415 #ifndef IPSEC 1416 /* 1417 * 'ia' may be NULL if there is no route for this destination. 1418 * In case of IPsec, Don't discard it just yet, but pass it to 1419 * ip_output in case of outgoing IPsec policy. 1420 */ 1421 if (!srcrt && ia == NULL) { 1422 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1423 return; 1424 } 1425 #endif 1426 1427 /* 1428 * Save the IP header and at most 8 bytes of the payload, 1429 * in case we need to generate an ICMP message to the src. 1430 * 1431 * XXX this can be optimized a lot by saving the data in a local 1432 * buffer on the stack (72 bytes at most), and only allocating the 1433 * mbuf if really necessary. The vast majority of the packets 1434 * are forwarded without having to send an ICMP back (either 1435 * because unnecessary, or because rate limited), so we are 1436 * really we are wasting a lot of work here. 1437 * 1438 * We don't use m_copy() because it might return a reference 1439 * to a shared cluster. Both this function and ip_output() 1440 * assume exclusive access to the IP header in `m', so any 1441 * data in a cluster may change before we reach icmp_error(). 1442 */ 1443 MGETHDR(mcopy, M_DONTWAIT, m->m_type); 1444 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1445 /* 1446 * It's probably ok if the pkthdr dup fails (because 1447 * the deep copy of the tag chain failed), but for now 1448 * be conservative and just discard the copy since 1449 * code below may some day want the tags. 1450 */ 1451 m_free(mcopy); 1452 mcopy = NULL; 1453 } 1454 if (mcopy != NULL) { 1455 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy)); 1456 mcopy->m_pkthdr.len = mcopy->m_len; 1457 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1458 } 1459 1460 #ifdef IPSTEALTH 1461 if (!V_ipstealth) { 1462 #endif 1463 ip->ip_ttl -= IPTTLDEC; 1464 #ifdef IPSTEALTH 1465 } 1466 #endif 1467 1468 /* 1469 * If forwarding packet using same interface that it came in on, 1470 * perhaps should send a redirect to sender to shortcut a hop. 1471 * Only send redirect if source is sending directly to us, 1472 * and if packet was not source routed (or has any options). 1473 * Also, don't send redirect if forwarding using a default route 1474 * or a route modified by a redirect. 1475 */ 1476 dest.s_addr = 0; 1477 if (!srcrt && V_ipsendredirects && 1478 ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) { 1479 struct sockaddr_in *sin; 1480 struct rtentry *rt; 1481 1482 bzero(&ro, sizeof(ro)); 1483 sin = (struct sockaddr_in *)&ro.ro_dst; 1484 sin->sin_family = AF_INET; 1485 sin->sin_len = sizeof(*sin); 1486 sin->sin_addr = ip->ip_dst; 1487 in_rtalloc_ign(&ro, 0, M_GETFIB(m)); 1488 1489 rt = ro.ro_rt; 1490 1491 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1492 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1493 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1494 u_long src = ntohl(ip->ip_src.s_addr); 1495 1496 if (RTA(rt) && 1497 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1498 if (rt->rt_flags & RTF_GATEWAY) 1499 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1500 else 1501 dest.s_addr = ip->ip_dst.s_addr; 1502 /* Router requirements says to only send host redirects */ 1503 type = ICMP_REDIRECT; 1504 code = ICMP_REDIRECT_HOST; 1505 } 1506 } 1507 if (rt) 1508 RTFREE(rt); 1509 } 1510 1511 /* 1512 * Try to cache the route MTU from ip_output so we can consider it for 1513 * the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191. 1514 */ 1515 bzero(&ro, sizeof(ro)); 1516 1517 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL); 1518 1519 if (error == EMSGSIZE && ro.ro_rt) 1520 mtu = ro.ro_rt->rt_rmx.rmx_mtu; 1521 if (ro.ro_rt) 1522 RTFREE(ro.ro_rt); 1523 1524 if (error) 1525 IPSTAT_INC(ips_cantforward); 1526 else { 1527 IPSTAT_INC(ips_forward); 1528 if (type) 1529 IPSTAT_INC(ips_redirectsent); 1530 else { 1531 if (mcopy) 1532 m_freem(mcopy); 1533 return; 1534 } 1535 } 1536 if (mcopy == NULL) 1537 return; 1538 1539 switch (error) { 1540 1541 case 0: /* forwarded, but need redirect */ 1542 /* type, code set above */ 1543 break; 1544 1545 case ENETUNREACH: 1546 case EHOSTUNREACH: 1547 case ENETDOWN: 1548 case EHOSTDOWN: 1549 default: 1550 type = ICMP_UNREACH; 1551 code = ICMP_UNREACH_HOST; 1552 break; 1553 1554 case EMSGSIZE: 1555 type = ICMP_UNREACH; 1556 code = ICMP_UNREACH_NEEDFRAG; 1557 1558 #ifdef IPSEC 1559 /* 1560 * If IPsec is configured for this path, 1561 * override any possibly mtu value set by ip_output. 1562 */ 1563 mtu = ip_ipsec_mtu(m, mtu); 1564 #endif /* IPSEC */ 1565 /* 1566 * If the MTU was set before make sure we are below the 1567 * interface MTU. 1568 * If the MTU wasn't set before use the interface mtu or 1569 * fall back to the next smaller mtu step compared to the 1570 * current packet size. 1571 */ 1572 if (mtu != 0) { 1573 if (ia != NULL) 1574 mtu = min(mtu, ia->ia_ifp->if_mtu); 1575 } else { 1576 if (ia != NULL) 1577 mtu = ia->ia_ifp->if_mtu; 1578 else 1579 mtu = ip_next_mtu(ip->ip_len, 0); 1580 } 1581 IPSTAT_INC(ips_cantfrag); 1582 break; 1583 1584 case ENOBUFS: 1585 /* 1586 * A router should not generate ICMP_SOURCEQUENCH as 1587 * required in RFC1812 Requirements for IP Version 4 Routers. 1588 * Source quench could be a big problem under DoS attacks, 1589 * or if the underlying interface is rate-limited. 1590 * Those who need source quench packets may re-enable them 1591 * via the net.inet.ip.sendsourcequench sysctl. 1592 */ 1593 if (V_ip_sendsourcequench == 0) { 1594 m_freem(mcopy); 1595 return; 1596 } else { 1597 type = ICMP_SOURCEQUENCH; 1598 code = 0; 1599 } 1600 break; 1601 1602 case EACCES: /* ipfw denied packet */ 1603 m_freem(mcopy); 1604 return; 1605 } 1606 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1607 } 1608 1609 void 1610 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1611 struct mbuf *m) 1612 { 1613 INIT_VNET_NET(inp->inp_vnet); 1614 1615 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1616 struct bintime bt; 1617 1618 bintime(&bt); 1619 if (inp->inp_socket->so_options & SO_BINTIME) { 1620 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 1621 SCM_BINTIME, SOL_SOCKET); 1622 if (*mp) 1623 mp = &(*mp)->m_next; 1624 } 1625 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1626 struct timeval tv; 1627 1628 bintime2timeval(&bt, &tv); 1629 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1630 SCM_TIMESTAMP, SOL_SOCKET); 1631 if (*mp) 1632 mp = &(*mp)->m_next; 1633 } 1634 } 1635 if (inp->inp_flags & INP_RECVDSTADDR) { 1636 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1637 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1638 if (*mp) 1639 mp = &(*mp)->m_next; 1640 } 1641 if (inp->inp_flags & INP_RECVTTL) { 1642 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1643 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1644 if (*mp) 1645 mp = &(*mp)->m_next; 1646 } 1647 #ifdef notyet 1648 /* XXX 1649 * Moving these out of udp_input() made them even more broken 1650 * than they already were. 1651 */ 1652 /* options were tossed already */ 1653 if (inp->inp_flags & INP_RECVOPTS) { 1654 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1655 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1656 if (*mp) 1657 mp = &(*mp)->m_next; 1658 } 1659 /* ip_srcroute doesn't do what we want here, need to fix */ 1660 if (inp->inp_flags & INP_RECVRETOPTS) { 1661 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1662 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1663 if (*mp) 1664 mp = &(*mp)->m_next; 1665 } 1666 #endif 1667 if (inp->inp_flags & INP_RECVIF) { 1668 struct ifnet *ifp; 1669 struct sdlbuf { 1670 struct sockaddr_dl sdl; 1671 u_char pad[32]; 1672 } sdlbuf; 1673 struct sockaddr_dl *sdp; 1674 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1675 1676 if (((ifp = m->m_pkthdr.rcvif)) 1677 && ( ifp->if_index && (ifp->if_index <= V_if_index))) { 1678 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1679 /* 1680 * Change our mind and don't try copy. 1681 */ 1682 if ((sdp->sdl_family != AF_LINK) 1683 || (sdp->sdl_len > sizeof(sdlbuf))) { 1684 goto makedummy; 1685 } 1686 bcopy(sdp, sdl2, sdp->sdl_len); 1687 } else { 1688 makedummy: 1689 sdl2->sdl_len 1690 = offsetof(struct sockaddr_dl, sdl_data[0]); 1691 sdl2->sdl_family = AF_LINK; 1692 sdl2->sdl_index = 0; 1693 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1694 } 1695 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1696 IP_RECVIF, IPPROTO_IP); 1697 if (*mp) 1698 mp = &(*mp)->m_next; 1699 } 1700 } 1701 1702 /* 1703 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the 1704 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on 1705 * locking. This code remains in ip_input.c as ip_mroute.c is optionally 1706 * compiled. 1707 */ 1708 int 1709 ip_rsvp_init(struct socket *so) 1710 { 1711 INIT_VNET_INET(so->so_vnet); 1712 1713 if (so->so_type != SOCK_RAW || 1714 so->so_proto->pr_protocol != IPPROTO_RSVP) 1715 return EOPNOTSUPP; 1716 1717 if (V_ip_rsvpd != NULL) 1718 return EADDRINUSE; 1719 1720 V_ip_rsvpd = so; 1721 /* 1722 * This may seem silly, but we need to be sure we don't over-increment 1723 * the RSVP counter, in case something slips up. 1724 */ 1725 if (!V_ip_rsvp_on) { 1726 V_ip_rsvp_on = 1; 1727 V_rsvp_on++; 1728 } 1729 1730 return 0; 1731 } 1732 1733 int 1734 ip_rsvp_done(void) 1735 { 1736 INIT_VNET_INET(curvnet); 1737 1738 V_ip_rsvpd = NULL; 1739 /* 1740 * This may seem silly, but we need to be sure we don't over-decrement 1741 * the RSVP counter, in case something slips up. 1742 */ 1743 if (V_ip_rsvp_on) { 1744 V_ip_rsvp_on = 0; 1745 V_rsvp_on--; 1746 } 1747 return 0; 1748 } 1749 1750 void 1751 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1752 { 1753 INIT_VNET_INET(curvnet); 1754 1755 if (rsvp_input_p) { /* call the real one if loaded */ 1756 rsvp_input_p(m, off); 1757 return; 1758 } 1759 1760 /* Can still get packets with rsvp_on = 0 if there is a local member 1761 * of the group to which the RSVP packet is addressed. But in this 1762 * case we want to throw the packet away. 1763 */ 1764 1765 if (!V_rsvp_on) { 1766 m_freem(m); 1767 return; 1768 } 1769 1770 if (V_ip_rsvpd != NULL) { 1771 rip_input(m, off); 1772 return; 1773 } 1774 /* Drop the packet */ 1775 m_freem(m); 1776 } 1777