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sys/netinet/ip_input.c
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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: releng/10.0/sys/netinet/ip_input.c 255523 2013-09-13 18:45:10Z trociny $"); 34 35 #include "opt_bootp.h" 36 #include "opt_ipfw.h" 37 #include "opt_ipstealth.h" 38 #include "opt_ipsec.h" 39 #include "opt_kdtrace.h" 40 #include "opt_route.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/mbuf.h> 45 #include <sys/malloc.h> 46 #include <sys/domain.h> 47 #include <sys/protosw.h> 48 #include <sys/socket.h> 49 #include <sys/time.h> 50 #include <sys/kernel.h> 51 #include <sys/lock.h> 52 #include <sys/rwlock.h> 53 #include <sys/sdt.h> 54 #include <sys/syslog.h> 55 #include <sys/sysctl.h> 56 57 #include <net/pfil.h> 58 #include <net/if.h> 59 #include <net/if_types.h> 60 #include <net/if_var.h> 61 #include <net/if_dl.h> 62 #include <net/route.h> 63 #include <net/netisr.h> 64 #include <net/vnet.h> 65 #include <net/flowtable.h> 66 67 #include <netinet/in.h> 68 #include <netinet/in_kdtrace.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_fw.h> 75 #include <netinet/ip_icmp.h> 76 #include <netinet/ip_options.h> 77 #include <machine/in_cksum.h> 78 #include <netinet/ip_carp.h> 79 #ifdef IPSEC 80 #include <netinet/ip_ipsec.h> 81 #endif /* IPSEC */ 82 83 #include <sys/socketvar.h> 84 85 #include <security/mac/mac_framework.h> 86 87 #ifdef CTASSERT 88 CTASSERT(sizeof(struct ip) == 20); 89 #endif 90 91 struct rwlock in_ifaddr_lock; 92 RW_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock"); 93 94 VNET_DEFINE(int, rsvp_on); 95 96 VNET_DEFINE(int, ipforwarding); 97 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 98 &VNET_NAME(ipforwarding), 0, 99 "Enable IP forwarding between interfaces"); 100 101 static VNET_DEFINE(int, ipsendredirects) = 1; /* XXX */ 102 #define V_ipsendredirects VNET(ipsendredirects) 103 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 104 &VNET_NAME(ipsendredirects), 0, 105 "Enable sending IP redirects"); 106 107 static VNET_DEFINE(int, ip_keepfaith); 108 #define V_ip_keepfaith VNET(ip_keepfaith) 109 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 110 &VNET_NAME(ip_keepfaith), 0, 111 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 112 113 static VNET_DEFINE(int, ip_sendsourcequench); 114 #define V_ip_sendsourcequench VNET(ip_sendsourcequench) 115 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 116 &VNET_NAME(ip_sendsourcequench), 0, 117 "Enable the transmission of source quench packets"); 118 119 VNET_DEFINE(int, ip_do_randomid); 120 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 121 &VNET_NAME(ip_do_randomid), 0, 122 "Assign random ip_id values"); 123 124 /* 125 * XXX - Setting ip_checkinterface mostly implements the receive side of 126 * the Strong ES model described in RFC 1122, but since the routing table 127 * and transmit implementation do not implement the Strong ES model, 128 * setting this to 1 results in an odd hybrid. 129 * 130 * XXX - ip_checkinterface currently must be disabled if you use ipnat 131 * to translate the destination address to another local interface. 132 * 133 * XXX - ip_checkinterface must be disabled if you add IP aliases 134 * to the loopback interface instead of the interface where the 135 * packets for those addresses are received. 136 */ 137 static VNET_DEFINE(int, ip_checkinterface); 138 #define V_ip_checkinterface VNET(ip_checkinterface) 139 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 140 &VNET_NAME(ip_checkinterface), 0, 141 "Verify packet arrives on correct interface"); 142 143 VNET_DEFINE(struct pfil_head, inet_pfil_hook); /* Packet filter hooks */ 144 145 static struct netisr_handler ip_nh = { 146 .nh_name = "ip", 147 .nh_handler = ip_input, 148 .nh_proto = NETISR_IP, 149 .nh_policy = NETISR_POLICY_FLOW, 150 }; 151 152 extern struct domain inetdomain; 153 extern struct protosw inetsw[]; 154 u_char ip_protox[IPPROTO_MAX]; 155 VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */ 156 VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */ 157 VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */ 158 159 static VNET_DEFINE(uma_zone_t, ipq_zone); 160 static VNET_DEFINE(TAILQ_HEAD(ipqhead, ipq), ipq[IPREASS_NHASH]); 161 static struct mtx ipqlock; 162 163 #define V_ipq_zone VNET(ipq_zone) 164 #define V_ipq VNET(ipq) 165 166 #define IPQ_LOCK() mtx_lock(&ipqlock) 167 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 168 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 169 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 170 171 static void maxnipq_update(void); 172 static void ipq_zone_change(void *); 173 static void ip_drain_locked(void); 174 175 static VNET_DEFINE(int, maxnipq); /* Administrative limit on # reass queues. */ 176 static VNET_DEFINE(int, nipq); /* Total # of reass queues */ 177 #define V_maxnipq VNET(maxnipq) 178 #define V_nipq VNET(nipq) 179 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, 180 &VNET_NAME(nipq), 0, 181 "Current number of IPv4 fragment reassembly queue entries"); 182 183 static VNET_DEFINE(int, maxfragsperpacket); 184 #define V_maxfragsperpacket VNET(maxfragsperpacket) 185 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 186 &VNET_NAME(maxfragsperpacket), 0, 187 "Maximum number of IPv4 fragments allowed per packet"); 188 189 #ifdef IPCTL_DEFMTU 190 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 191 &ip_mtu, 0, "Default MTU"); 192 #endif 193 194 #ifdef IPSTEALTH 195 VNET_DEFINE(int, ipstealth); 196 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 197 &VNET_NAME(ipstealth), 0, 198 "IP stealth mode, no TTL decrementation on forwarding"); 199 #endif 200 201 #ifdef FLOWTABLE 202 static VNET_DEFINE(int, ip_output_flowtable_size) = 2048; 203 VNET_DEFINE(struct flowtable *, ip_ft); 204 #define V_ip_output_flowtable_size VNET(ip_output_flowtable_size) 205 206 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, output_flowtable_size, CTLFLAG_RDTUN, 207 &VNET_NAME(ip_output_flowtable_size), 2048, 208 "number of entries in the per-cpu output flow caches"); 209 #endif 210 211 static void ip_freef(struct ipqhead *, struct ipq *); 212 213 /* 214 * IP statistics are stored in the "array" of counter(9)s. 215 */ 216 VNET_PCPUSTAT_DEFINE(struct ipstat, ipstat); 217 VNET_PCPUSTAT_SYSINIT(ipstat); 218 SYSCTL_VNET_PCPUSTAT(_net_inet_ip, IPCTL_STATS, stats, struct ipstat, ipstat, 219 "IP statistics (struct ipstat, netinet/ip_var.h)"); 220 221 #ifdef VIMAGE 222 VNET_PCPUSTAT_SYSUNINIT(ipstat); 223 #endif /* VIMAGE */ 224 225 /* 226 * Kernel module interface for updating ipstat. The argument is an index 227 * into ipstat treated as an array. 228 */ 229 void 230 kmod_ipstat_inc(int statnum) 231 { 232 233 counter_u64_add(VNET(ipstat)[statnum], 1); 234 } 235 236 void 237 kmod_ipstat_dec(int statnum) 238 { 239 240 counter_u64_add(VNET(ipstat)[statnum], -1); 241 } 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 struct protosw *pr; 289 int i; 290 291 V_ip_id = time_second & 0xffff; 292 293 TAILQ_INIT(&V_in_ifaddrhead); 294 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask); 295 296 /* Initialize IP reassembly queue. */ 297 for (i = 0; i < IPREASS_NHASH; i++) 298 TAILQ_INIT(&V_ipq[i]); 299 V_maxnipq = nmbclusters / 32; 300 V_maxfragsperpacket = 16; 301 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 302 NULL, UMA_ALIGN_PTR, 0); 303 maxnipq_update(); 304 305 /* Initialize packet filter hooks. */ 306 V_inet_pfil_hook.ph_type = PFIL_TYPE_AF; 307 V_inet_pfil_hook.ph_af = AF_INET; 308 if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0) 309 printf("%s: WARNING: unable to register pfil hook, " 310 "error %d\n", __func__, i); 311 312 #ifdef FLOWTABLE 313 if (TUNABLE_INT_FETCH("net.inet.ip.output_flowtable_size", 314 &V_ip_output_flowtable_size)) { 315 if (V_ip_output_flowtable_size < 256) 316 V_ip_output_flowtable_size = 256; 317 if (!powerof2(V_ip_output_flowtable_size)) { 318 printf("flowtable must be power of 2 size\n"); 319 V_ip_output_flowtable_size = 2048; 320 } 321 } else { 322 /* 323 * round up to the next power of 2 324 */ 325 V_ip_output_flowtable_size = 1 << fls((1024 + maxusers * 64)-1); 326 } 327 V_ip_ft = flowtable_alloc("ipv4", V_ip_output_flowtable_size, FL_PCPU); 328 #endif 329 330 /* Skip initialization of globals for non-default instances. */ 331 if (!IS_DEFAULT_VNET(curvnet)) 332 return; 333 334 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 335 if (pr == NULL) 336 panic("ip_init: PF_INET not found"); 337 338 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 339 for (i = 0; i < IPPROTO_MAX; i++) 340 ip_protox[i] = pr - inetsw; 341 /* 342 * Cycle through IP protocols and put them into the appropriate place 343 * in ip_protox[]. 344 */ 345 for (pr = inetdomain.dom_protosw; 346 pr < inetdomain.dom_protoswNPROTOSW; pr++) 347 if (pr->pr_domain->dom_family == PF_INET && 348 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 349 /* Be careful to only index valid IP protocols. */ 350 if (pr->pr_protocol < IPPROTO_MAX) 351 ip_protox[pr->pr_protocol] = pr - inetsw; 352 } 353 354 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, 355 NULL, EVENTHANDLER_PRI_ANY); 356 357 /* Initialize various other remaining things. */ 358 IPQ_LOCK_INIT(); 359 netisr_register(&ip_nh); 360 } 361 362 #ifdef VIMAGE 363 void 364 ip_destroy(void) 365 { 366 int i; 367 368 if ((i = pfil_head_unregister(&V_inet_pfil_hook)) != 0) 369 printf("%s: WARNING: unable to unregister pfil hook, " 370 "error %d\n", __func__, i); 371 372 /* Cleanup in_ifaddr hash table; should be empty. */ 373 hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask); 374 375 IPQ_LOCK(); 376 ip_drain_locked(); 377 IPQ_UNLOCK(); 378 379 uma_zdestroy(V_ipq_zone); 380 } 381 #endif 382 383 /* 384 * Ip input routine. Checksum and byte swap header. If fragmented 385 * try to reassemble. Process options. Pass to next level. 386 */ 387 void 388 ip_input(struct mbuf *m) 389 { 390 struct ip *ip = NULL; 391 struct in_ifaddr *ia = NULL; 392 struct ifaddr *ifa; 393 struct ifnet *ifp; 394 int checkif, hlen = 0; 395 uint16_t sum, ip_len; 396 int dchg = 0; /* dest changed after fw */ 397 struct in_addr odst; /* original dst address */ 398 399 M_ASSERTPKTHDR(m); 400 401 if (m->m_flags & M_FASTFWD_OURS) { 402 m->m_flags &= ~M_FASTFWD_OURS; 403 /* Set up some basics that will be used later. */ 404 ip = mtod(m, struct ip *); 405 hlen = ip->ip_hl << 2; 406 ip_len = ntohs(ip->ip_len); 407 goto ours; 408 } 409 410 IPSTAT_INC(ips_total); 411 412 if (m->m_pkthdr.len < sizeof(struct ip)) 413 goto tooshort; 414 415 if (m->m_len < sizeof (struct ip) && 416 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 417 IPSTAT_INC(ips_toosmall); 418 return; 419 } 420 ip = mtod(m, struct ip *); 421 422 if (ip->ip_v != IPVERSION) { 423 IPSTAT_INC(ips_badvers); 424 goto bad; 425 } 426 427 hlen = ip->ip_hl << 2; 428 if (hlen < sizeof(struct ip)) { /* minimum header length */ 429 IPSTAT_INC(ips_badhlen); 430 goto bad; 431 } 432 if (hlen > m->m_len) { 433 if ((m = m_pullup(m, hlen)) == NULL) { 434 IPSTAT_INC(ips_badhlen); 435 return; 436 } 437 ip = mtod(m, struct ip *); 438 } 439 440 IP_PROBE(receive, NULL, NULL, ip, m->m_pkthdr.rcvif, ip, NULL); 441 442 /* 127/8 must not appear on wire - RFC1122 */ 443 ifp = m->m_pkthdr.rcvif; 444 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 445 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 446 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 447 IPSTAT_INC(ips_badaddr); 448 goto bad; 449 } 450 } 451 452 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 453 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 454 } else { 455 if (hlen == sizeof(struct ip)) { 456 sum = in_cksum_hdr(ip); 457 } else { 458 sum = in_cksum(m, hlen); 459 } 460 } 461 if (sum) { 462 IPSTAT_INC(ips_badsum); 463 goto bad; 464 } 465 466 #ifdef ALTQ 467 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 468 /* packet is dropped by traffic conditioner */ 469 return; 470 #endif 471 472 ip_len = ntohs(ip->ip_len); 473 if (ip_len < hlen) { 474 IPSTAT_INC(ips_badlen); 475 goto bad; 476 } 477 478 /* 479 * Check that the amount of data in the buffers 480 * is as at least much as the IP header would have us expect. 481 * Trim mbufs if longer than we expect. 482 * Drop packet if shorter than we expect. 483 */ 484 if (m->m_pkthdr.len < ip_len) { 485 tooshort: 486 IPSTAT_INC(ips_tooshort); 487 goto bad; 488 } 489 if (m->m_pkthdr.len > ip_len) { 490 if (m->m_len == m->m_pkthdr.len) { 491 m->m_len = ip_len; 492 m->m_pkthdr.len = ip_len; 493 } else 494 m_adj(m, ip_len - m->m_pkthdr.len); 495 } 496 #ifdef IPSEC 497 /* 498 * Bypass packet filtering for packets previously handled by IPsec. 499 */ 500 if (ip_ipsec_filtertunnel(m)) 501 goto passin; 502 #endif /* IPSEC */ 503 504 /* 505 * Run through list of hooks for input packets. 506 * 507 * NB: Beware of the destination address changing (e.g. 508 * by NAT rewriting). When this happens, tell 509 * ip_forward to do the right thing. 510 */ 511 512 /* Jump over all PFIL processing if hooks are not active. */ 513 if (!PFIL_HOOKED(&V_inet_pfil_hook)) 514 goto passin; 515 516 odst = ip->ip_dst; 517 if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0) 518 return; 519 if (m == NULL) /* consumed by filter */ 520 return; 521 522 ip = mtod(m, struct ip *); 523 dchg = (odst.s_addr != ip->ip_dst.s_addr); 524 ifp = m->m_pkthdr.rcvif; 525 526 if (m->m_flags & M_FASTFWD_OURS) { 527 m->m_flags &= ~M_FASTFWD_OURS; 528 goto ours; 529 } 530 if (m->m_flags & M_IP_NEXTHOP) { 531 dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL); 532 if (dchg != 0) { 533 /* 534 * Directly ship the packet on. This allows 535 * forwarding packets originally destined to us 536 * to some other directly connected host. 537 */ 538 ip_forward(m, 1); 539 return; 540 } 541 } 542 passin: 543 544 /* 545 * Process options and, if not destined for us, 546 * ship it on. ip_dooptions returns 1 when an 547 * error was detected (causing an icmp message 548 * to be sent and the original packet to be freed). 549 */ 550 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 551 return; 552 553 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 554 * matter if it is destined to another node, or whether it is 555 * a multicast one, RSVP wants it! and prevents it from being forwarded 556 * anywhere else. Also checks if the rsvp daemon is running before 557 * grabbing the packet. 558 */ 559 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP) 560 goto ours; 561 562 /* 563 * Check our list of addresses, to see if the packet is for us. 564 * If we don't have any addresses, assume any unicast packet 565 * we receive might be for us (and let the upper layers deal 566 * with it). 567 */ 568 if (TAILQ_EMPTY(&V_in_ifaddrhead) && 569 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 570 goto ours; 571 572 /* 573 * Enable a consistency check between the destination address 574 * and the arrival interface for a unicast packet (the RFC 1122 575 * strong ES model) if IP forwarding is disabled and the packet 576 * is not locally generated and the packet is not subject to 577 * 'ipfw fwd'. 578 * 579 * XXX - Checking also should be disabled if the destination 580 * address is ipnat'ed to a different interface. 581 * 582 * XXX - Checking is incompatible with IP aliases added 583 * to the loopback interface instead of the interface where 584 * the packets are received. 585 * 586 * XXX - This is the case for carp vhost IPs as well so we 587 * insert a workaround. If the packet got here, we already 588 * checked with carp_iamatch() and carp_forus(). 589 */ 590 checkif = V_ip_checkinterface && (V_ipforwarding == 0) && 591 ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) && 592 ifp->if_carp == NULL && (dchg == 0); 593 594 /* 595 * Check for exact addresses in the hash bucket. 596 */ 597 /* IN_IFADDR_RLOCK(); */ 598 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 599 /* 600 * If the address matches, verify that the packet 601 * arrived via the correct interface if checking is 602 * enabled. 603 */ 604 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 605 (!checkif || ia->ia_ifp == ifp)) { 606 ifa_ref(&ia->ia_ifa); 607 /* IN_IFADDR_RUNLOCK(); */ 608 goto ours; 609 } 610 } 611 /* IN_IFADDR_RUNLOCK(); */ 612 613 /* 614 * Check for broadcast addresses. 615 * 616 * Only accept broadcast packets that arrive via the matching 617 * interface. Reception of forwarded directed broadcasts would 618 * be handled via ip_forward() and ether_output() with the loopback 619 * into the stack for SIMPLEX interfaces handled by ether_output(). 620 */ 621 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) { 622 IF_ADDR_RLOCK(ifp); 623 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 624 if (ifa->ifa_addr->sa_family != AF_INET) 625 continue; 626 ia = ifatoia(ifa); 627 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 628 ip->ip_dst.s_addr) { 629 ifa_ref(ifa); 630 IF_ADDR_RUNLOCK(ifp); 631 goto ours; 632 } 633 #ifdef BOOTP_COMPAT 634 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) { 635 ifa_ref(ifa); 636 IF_ADDR_RUNLOCK(ifp); 637 goto ours; 638 } 639 #endif 640 } 641 IF_ADDR_RUNLOCK(ifp); 642 ia = NULL; 643 } 644 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */ 645 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) { 646 IPSTAT_INC(ips_cantforward); 647 m_freem(m); 648 return; 649 } 650 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 651 if (V_ip_mrouter) { 652 /* 653 * If we are acting as a multicast router, all 654 * incoming multicast packets are passed to the 655 * kernel-level multicast forwarding function. 656 * The packet is returned (relatively) intact; if 657 * ip_mforward() returns a non-zero value, the packet 658 * must be discarded, else it may be accepted below. 659 */ 660 if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) { 661 IPSTAT_INC(ips_cantforward); 662 m_freem(m); 663 return; 664 } 665 666 /* 667 * The process-level routing daemon needs to receive 668 * all multicast IGMP packets, whether or not this 669 * host belongs to their destination groups. 670 */ 671 if (ip->ip_p == IPPROTO_IGMP) 672 goto ours; 673 IPSTAT_INC(ips_forward); 674 } 675 /* 676 * Assume the packet is for us, to avoid prematurely taking 677 * a lock on the in_multi hash. Protocols must perform 678 * their own filtering and update statistics accordingly. 679 */ 680 goto ours; 681 } 682 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 683 goto ours; 684 if (ip->ip_dst.s_addr == INADDR_ANY) 685 goto ours; 686 687 /* 688 * FAITH(Firewall Aided Internet Translator) 689 */ 690 if (ifp && ifp->if_type == IFT_FAITH) { 691 if (V_ip_keepfaith) { 692 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 693 goto ours; 694 } 695 m_freem(m); 696 return; 697 } 698 699 /* 700 * Not for us; forward if possible and desirable. 701 */ 702 if (V_ipforwarding == 0) { 703 IPSTAT_INC(ips_cantforward); 704 m_freem(m); 705 } else { 706 #ifdef IPSEC 707 if (ip_ipsec_fwd(m)) 708 goto bad; 709 #endif /* IPSEC */ 710 ip_forward(m, dchg); 711 } 712 return; 713 714 ours: 715 #ifdef IPSTEALTH 716 /* 717 * IPSTEALTH: Process non-routing options only 718 * if the packet is destined for us. 719 */ 720 if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1)) { 721 if (ia != NULL) 722 ifa_free(&ia->ia_ifa); 723 return; 724 } 725 #endif /* IPSTEALTH */ 726 727 /* Count the packet in the ip address stats */ 728 if (ia != NULL) { 729 ia->ia_ifa.if_ipackets++; 730 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 731 ifa_free(&ia->ia_ifa); 732 } 733 734 /* 735 * Attempt reassembly; if it succeeds, proceed. 736 * ip_reass() will return a different mbuf. 737 */ 738 if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) { 739 m = ip_reass(m); 740 if (m == NULL) 741 return; 742 ip = mtod(m, struct ip *); 743 /* Get the header length of the reassembled packet */ 744 hlen = ip->ip_hl << 2; 745 } 746 747 #ifdef IPSEC 748 /* 749 * enforce IPsec policy checking if we are seeing last header. 750 * note that we do not visit this with protocols with pcb layer 751 * code - like udp/tcp/raw ip. 752 */ 753 if (ip_ipsec_input(m)) 754 goto bad; 755 #endif /* IPSEC */ 756 757 /* 758 * Switch out to protocol's input routine. 759 */ 760 IPSTAT_INC(ips_delivered); 761 762 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 763 return; 764 bad: 765 m_freem(m); 766 } 767 768 /* 769 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 770 * max has slightly different semantics than the sysctl, for historical 771 * reasons. 772 */ 773 static void 774 maxnipq_update(void) 775 { 776 777 /* 778 * -1 for unlimited allocation. 779 */ 780 if (V_maxnipq < 0) 781 uma_zone_set_max(V_ipq_zone, 0); 782 /* 783 * Positive number for specific bound. 784 */ 785 if (V_maxnipq > 0) 786 uma_zone_set_max(V_ipq_zone, V_maxnipq); 787 /* 788 * Zero specifies no further fragment queue allocation -- set the 789 * bound very low, but rely on implementation elsewhere to actually 790 * prevent allocation and reclaim current queues. 791 */ 792 if (V_maxnipq == 0) 793 uma_zone_set_max(V_ipq_zone, 1); 794 } 795 796 static void 797 ipq_zone_change(void *tag) 798 { 799 800 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) { 801 V_maxnipq = nmbclusters / 32; 802 maxnipq_update(); 803 } 804 } 805 806 static int 807 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 808 { 809 int error, i; 810 811 i = V_maxnipq; 812 error = sysctl_handle_int(oidp, &i, 0, req); 813 if (error || !req->newptr) 814 return (error); 815 816 /* 817 * XXXRW: Might be a good idea to sanity check the argument and place 818 * an extreme upper bound. 819 */ 820 if (i < -1) 821 return (EINVAL); 822 V_maxnipq = i; 823 maxnipq_update(); 824 return (0); 825 } 826 827 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 828 NULL, 0, sysctl_maxnipq, "I", 829 "Maximum number of IPv4 fragment reassembly queue entries"); 830 831 /* 832 * Take incoming datagram fragment and try to reassemble it into 833 * whole datagram. If the argument is the first fragment or one 834 * in between the function will return NULL and store the mbuf 835 * in the fragment chain. If the argument is the last fragment 836 * the packet will be reassembled and the pointer to the new 837 * mbuf returned for further processing. Only m_tags attached 838 * to the first packet/fragment are preserved. 839 * The IP header is *NOT* adjusted out of iplen. 840 */ 841 struct mbuf * 842 ip_reass(struct mbuf *m) 843 { 844 struct ip *ip; 845 struct mbuf *p, *q, *nq, *t; 846 struct ipq *fp = NULL; 847 struct ipqhead *head; 848 int i, hlen, next; 849 u_int8_t ecn, ecn0; 850 u_short hash; 851 852 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 853 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) { 854 IPSTAT_INC(ips_fragments); 855 IPSTAT_INC(ips_fragdropped); 856 m_freem(m); 857 return (NULL); 858 } 859 860 ip = mtod(m, struct ip *); 861 hlen = ip->ip_hl << 2; 862 863 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 864 head = &V_ipq[hash]; 865 IPQ_LOCK(); 866 867 /* 868 * Look for queue of fragments 869 * of this datagram. 870 */ 871 TAILQ_FOREACH(fp, head, ipq_list) 872 if (ip->ip_id == fp->ipq_id && 873 ip->ip_src.s_addr == fp->ipq_src.s_addr && 874 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 875 #ifdef MAC 876 mac_ipq_match(m, fp) && 877 #endif 878 ip->ip_p == fp->ipq_p) 879 goto found; 880 881 fp = NULL; 882 883 /* 884 * Attempt to trim the number of allocated fragment queues if it 885 * exceeds the administrative limit. 886 */ 887 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) { 888 /* 889 * drop something from the tail of the current queue 890 * before proceeding further 891 */ 892 struct ipq *q = TAILQ_LAST(head, ipqhead); 893 if (q == NULL) { /* gak */ 894 for (i = 0; i < IPREASS_NHASH; i++) { 895 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead); 896 if (r) { 897 IPSTAT_ADD(ips_fragtimeout, 898 r->ipq_nfrags); 899 ip_freef(&V_ipq[i], r); 900 break; 901 } 902 } 903 } else { 904 IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags); 905 ip_freef(head, q); 906 } 907 } 908 909 found: 910 /* 911 * Adjust ip_len to not reflect header, 912 * convert offset of this to bytes. 913 */ 914 ip->ip_len = htons(ntohs(ip->ip_len) - hlen); 915 if (ip->ip_off & htons(IP_MF)) { 916 /* 917 * Make sure that fragments have a data length 918 * that's a non-zero multiple of 8 bytes. 919 */ 920 if (ip->ip_len == htons(0) || (ntohs(ip->ip_len) & 0x7) != 0) { 921 IPSTAT_INC(ips_toosmall); /* XXX */ 922 goto dropfrag; 923 } 924 m->m_flags |= M_IP_FRAG; 925 } else 926 m->m_flags &= ~M_IP_FRAG; 927 ip->ip_off = htons(ntohs(ip->ip_off) << 3); 928 929 /* 930 * Attempt reassembly; if it succeeds, proceed. 931 * ip_reass() will return a different mbuf. 932 */ 933 IPSTAT_INC(ips_fragments); 934 m->m_pkthdr.PH_loc.ptr = ip; 935 936 /* Previous ip_reass() started here. */ 937 /* 938 * Presence of header sizes in mbufs 939 * would confuse code below. 940 */ 941 m->m_data += hlen; 942 m->m_len -= hlen; 943 944 /* 945 * If first fragment to arrive, create a reassembly queue. 946 */ 947 if (fp == NULL) { 948 fp = uma_zalloc(V_ipq_zone, M_NOWAIT); 949 if (fp == NULL) 950 goto dropfrag; 951 #ifdef MAC 952 if (mac_ipq_init(fp, M_NOWAIT) != 0) { 953 uma_zfree(V_ipq_zone, fp); 954 fp = NULL; 955 goto dropfrag; 956 } 957 mac_ipq_create(m, fp); 958 #endif 959 TAILQ_INSERT_HEAD(head, fp, ipq_list); 960 V_nipq++; 961 fp->ipq_nfrags = 1; 962 fp->ipq_ttl = IPFRAGTTL; 963 fp->ipq_p = ip->ip_p; 964 fp->ipq_id = ip->ip_id; 965 fp->ipq_src = ip->ip_src; 966 fp->ipq_dst = ip->ip_dst; 967 fp->ipq_frags = m; 968 m->m_nextpkt = NULL; 969 goto done; 970 } else { 971 fp->ipq_nfrags++; 972 #ifdef MAC 973 mac_ipq_update(m, fp); 974 #endif 975 } 976 977 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.PH_loc.ptr)) 978 979 /* 980 * Handle ECN by comparing this segment with the first one; 981 * if CE is set, do not lose CE. 982 * drop if CE and not-ECT are mixed for the same packet. 983 */ 984 ecn = ip->ip_tos & IPTOS_ECN_MASK; 985 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 986 if (ecn == IPTOS_ECN_CE) { 987 if (ecn0 == IPTOS_ECN_NOTECT) 988 goto dropfrag; 989 if (ecn0 != IPTOS_ECN_CE) 990 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 991 } 992 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 993 goto dropfrag; 994 995 /* 996 * Find a segment which begins after this one does. 997 */ 998 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 999 if (ntohs(GETIP(q)->ip_off) > ntohs(ip->ip_off)) 1000 break; 1001 1002 /* 1003 * If there is a preceding segment, it may provide some of 1004 * our data already. If so, drop the data from the incoming 1005 * segment. If it provides all of our data, drop us, otherwise 1006 * stick new segment in the proper place. 1007 * 1008 * If some of the data is dropped from the preceding 1009 * segment, then it's checksum is invalidated. 1010 */ 1011 if (p) { 1012 i = ntohs(GETIP(p)->ip_off) + ntohs(GETIP(p)->ip_len) - 1013 ntohs(ip->ip_off); 1014 if (i > 0) { 1015 if (i >= ntohs(ip->ip_len)) 1016 goto dropfrag; 1017 m_adj(m, i); 1018 m->m_pkthdr.csum_flags = 0; 1019 ip->ip_off = htons(ntohs(ip->ip_off) + i); 1020 ip->ip_len = htons(ntohs(ip->ip_len) - i); 1021 } 1022 m->m_nextpkt = p->m_nextpkt; 1023 p->m_nextpkt = m; 1024 } else { 1025 m->m_nextpkt = fp->ipq_frags; 1026 fp->ipq_frags = m; 1027 } 1028 1029 /* 1030 * While we overlap succeeding segments trim them or, 1031 * if they are completely covered, dequeue them. 1032 */ 1033 for (; q != NULL && ntohs(ip->ip_off) + ntohs(ip->ip_len) > 1034 ntohs(GETIP(q)->ip_off); q = nq) { 1035 i = (ntohs(ip->ip_off) + ntohs(ip->ip_len)) - 1036 ntohs(GETIP(q)->ip_off); 1037 if (i < ntohs(GETIP(q)->ip_len)) { 1038 GETIP(q)->ip_len = htons(ntohs(GETIP(q)->ip_len) - i); 1039 GETIP(q)->ip_off = htons(ntohs(GETIP(q)->ip_off) + i); 1040 m_adj(q, i); 1041 q->m_pkthdr.csum_flags = 0; 1042 break; 1043 } 1044 nq = q->m_nextpkt; 1045 m->m_nextpkt = nq; 1046 IPSTAT_INC(ips_fragdropped); 1047 fp->ipq_nfrags--; 1048 m_freem(q); 1049 } 1050 1051 /* 1052 * Check for complete reassembly and perform frag per packet 1053 * limiting. 1054 * 1055 * Frag limiting is performed here so that the nth frag has 1056 * a chance to complete the packet before we drop the packet. 1057 * As a result, n+1 frags are actually allowed per packet, but 1058 * only n will ever be stored. (n = maxfragsperpacket.) 1059 * 1060 */ 1061 next = 0; 1062 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1063 if (ntohs(GETIP(q)->ip_off) != next) { 1064 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1065 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1066 ip_freef(head, fp); 1067 } 1068 goto done; 1069 } 1070 next += ntohs(GETIP(q)->ip_len); 1071 } 1072 /* Make sure the last packet didn't have the IP_MF flag */ 1073 if (p->m_flags & M_IP_FRAG) { 1074 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1075 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1076 ip_freef(head, fp); 1077 } 1078 goto done; 1079 } 1080 1081 /* 1082 * Reassembly is complete. Make sure the packet is a sane size. 1083 */ 1084 q = fp->ipq_frags; 1085 ip = GETIP(q); 1086 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1087 IPSTAT_INC(ips_toolong); 1088 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1089 ip_freef(head, fp); 1090 goto done; 1091 } 1092 1093 /* 1094 * Concatenate fragments. 1095 */ 1096 m = q; 1097 t = m->m_next; 1098 m->m_next = NULL; 1099 m_cat(m, t); 1100 nq = q->m_nextpkt; 1101 q->m_nextpkt = NULL; 1102 for (q = nq; q != NULL; q = nq) { 1103 nq = q->m_nextpkt; 1104 q->m_nextpkt = NULL; 1105 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1106 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1107 m_cat(m, q); 1108 } 1109 /* 1110 * In order to do checksumming faster we do 'end-around carry' here 1111 * (and not in for{} loop), though it implies we are not going to 1112 * reassemble more than 64k fragments. 1113 */ 1114 m->m_pkthdr.csum_data = 1115 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1116 #ifdef MAC 1117 mac_ipq_reassemble(fp, m); 1118 mac_ipq_destroy(fp); 1119 #endif 1120 1121 /* 1122 * Create header for new ip packet by modifying header of first 1123 * packet; dequeue and discard fragment reassembly header. 1124 * Make header visible. 1125 */ 1126 ip->ip_len = htons((ip->ip_hl << 2) + next); 1127 ip->ip_src = fp->ipq_src; 1128 ip->ip_dst = fp->ipq_dst; 1129 TAILQ_REMOVE(head, fp, ipq_list); 1130 V_nipq--; 1131 uma_zfree(V_ipq_zone, fp); 1132 m->m_len += (ip->ip_hl << 2); 1133 m->m_data -= (ip->ip_hl << 2); 1134 /* some debugging cruft by sklower, below, will go away soon */ 1135 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1136 m_fixhdr(m); 1137 IPSTAT_INC(ips_reassembled); 1138 IPQ_UNLOCK(); 1139 return (m); 1140 1141 dropfrag: 1142 IPSTAT_INC(ips_fragdropped); 1143 if (fp != NULL) 1144 fp->ipq_nfrags--; 1145 m_freem(m); 1146 done: 1147 IPQ_UNLOCK(); 1148 return (NULL); 1149 1150 #undef GETIP 1151 } 1152 1153 /* 1154 * Free a fragment reassembly header and all 1155 * associated datagrams. 1156 */ 1157 static void 1158 ip_freef(struct ipqhead *fhp, struct ipq *fp) 1159 { 1160 struct mbuf *q; 1161 1162 IPQ_LOCK_ASSERT(); 1163 1164 while (fp->ipq_frags) { 1165 q = fp->ipq_frags; 1166 fp->ipq_frags = q->m_nextpkt; 1167 m_freem(q); 1168 } 1169 TAILQ_REMOVE(fhp, fp, ipq_list); 1170 uma_zfree(V_ipq_zone, fp); 1171 V_nipq--; 1172 } 1173 1174 /* 1175 * IP timer processing; 1176 * if a timer expires on a reassembly 1177 * queue, discard it. 1178 */ 1179 void 1180 ip_slowtimo(void) 1181 { 1182 VNET_ITERATOR_DECL(vnet_iter); 1183 struct ipq *fp; 1184 int i; 1185 1186 VNET_LIST_RLOCK_NOSLEEP(); 1187 IPQ_LOCK(); 1188 VNET_FOREACH(vnet_iter) { 1189 CURVNET_SET(vnet_iter); 1190 for (i = 0; i < IPREASS_NHASH; i++) { 1191 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) { 1192 struct ipq *fpp; 1193 1194 fpp = fp; 1195 fp = TAILQ_NEXT(fp, ipq_list); 1196 if(--fpp->ipq_ttl == 0) { 1197 IPSTAT_ADD(ips_fragtimeout, 1198 fpp->ipq_nfrags); 1199 ip_freef(&V_ipq[i], fpp); 1200 } 1201 } 1202 } 1203 /* 1204 * If we are over the maximum number of fragments 1205 * (due to the limit being lowered), drain off 1206 * enough to get down to the new limit. 1207 */ 1208 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) { 1209 for (i = 0; i < IPREASS_NHASH; i++) { 1210 while (V_nipq > V_maxnipq && 1211 !TAILQ_EMPTY(&V_ipq[i])) { 1212 IPSTAT_ADD(ips_fragdropped, 1213 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1214 ip_freef(&V_ipq[i], 1215 TAILQ_FIRST(&V_ipq[i])); 1216 } 1217 } 1218 } 1219 CURVNET_RESTORE(); 1220 } 1221 IPQ_UNLOCK(); 1222 VNET_LIST_RUNLOCK_NOSLEEP(); 1223 } 1224 1225 /* 1226 * Drain off all datagram fragments. 1227 */ 1228 static void 1229 ip_drain_locked(void) 1230 { 1231 int i; 1232 1233 IPQ_LOCK_ASSERT(); 1234 1235 for (i = 0; i < IPREASS_NHASH; i++) { 1236 while(!TAILQ_EMPTY(&V_ipq[i])) { 1237 IPSTAT_ADD(ips_fragdropped, 1238 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1239 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i])); 1240 } 1241 } 1242 } 1243 1244 void 1245 ip_drain(void) 1246 { 1247 VNET_ITERATOR_DECL(vnet_iter); 1248 1249 VNET_LIST_RLOCK_NOSLEEP(); 1250 IPQ_LOCK(); 1251 VNET_FOREACH(vnet_iter) { 1252 CURVNET_SET(vnet_iter); 1253 ip_drain_locked(); 1254 CURVNET_RESTORE(); 1255 } 1256 IPQ_UNLOCK(); 1257 VNET_LIST_RUNLOCK_NOSLEEP(); 1258 in_rtqdrain(); 1259 } 1260 1261 /* 1262 * The protocol to be inserted into ip_protox[] must be already registered 1263 * in inetsw[], either statically or through pf_proto_register(). 1264 */ 1265 int 1266 ipproto_register(short ipproto) 1267 { 1268 struct protosw *pr; 1269 1270 /* Sanity checks. */ 1271 if (ipproto <= 0 || ipproto >= IPPROTO_MAX) 1272 return (EPROTONOSUPPORT); 1273 1274 /* 1275 * The protocol slot must not be occupied by another protocol 1276 * already. An index pointing to IPPROTO_RAW is unused. 1277 */ 1278 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1279 if (pr == NULL) 1280 return (EPFNOSUPPORT); 1281 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1282 return (EEXIST); 1283 1284 /* Find the protocol position in inetsw[] and set the index. */ 1285 for (pr = inetdomain.dom_protosw; 1286 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1287 if (pr->pr_domain->dom_family == PF_INET && 1288 pr->pr_protocol && pr->pr_protocol == ipproto) { 1289 ip_protox[pr->pr_protocol] = pr - inetsw; 1290 return (0); 1291 } 1292 } 1293 return (EPROTONOSUPPORT); 1294 } 1295 1296 int 1297 ipproto_unregister(short ipproto) 1298 { 1299 struct protosw *pr; 1300 1301 /* Sanity checks. */ 1302 if (ipproto <= 0 || ipproto >= IPPROTO_MAX) 1303 return (EPROTONOSUPPORT); 1304 1305 /* Check if the protocol was indeed registered. */ 1306 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1307 if (pr == NULL) 1308 return (EPFNOSUPPORT); 1309 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1310 return (ENOENT); 1311 1312 /* Reset the protocol slot to IPPROTO_RAW. */ 1313 ip_protox[ipproto] = pr - inetsw; 1314 return (0); 1315 } 1316 1317 /* 1318 * Given address of next destination (final or next hop), return (referenced) 1319 * internet address info of interface to be used to get there. 1320 */ 1321 struct in_ifaddr * 1322 ip_rtaddr(struct in_addr dst, u_int fibnum) 1323 { 1324 struct route sro; 1325 struct sockaddr_in *sin; 1326 struct in_ifaddr *ia; 1327 1328 bzero(&sro, sizeof(sro)); 1329 sin = (struct sockaddr_in *)&sro.ro_dst; 1330 sin->sin_family = AF_INET; 1331 sin->sin_len = sizeof(*sin); 1332 sin->sin_addr = dst; 1333 in_rtalloc_ign(&sro, 0, fibnum); 1334 1335 if (sro.ro_rt == NULL) 1336 return (NULL); 1337 1338 ia = ifatoia(sro.ro_rt->rt_ifa); 1339 ifa_ref(&ia->ia_ifa); 1340 RTFREE(sro.ro_rt); 1341 return (ia); 1342 } 1343 1344 u_char inetctlerrmap[PRC_NCMDS] = { 1345 0, 0, 0, 0, 1346 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1347 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1348 EMSGSIZE, EHOSTUNREACH, 0, 0, 1349 0, 0, EHOSTUNREACH, 0, 1350 ENOPROTOOPT, ECONNREFUSED 1351 }; 1352 1353 /* 1354 * Forward a packet. If some error occurs return the sender 1355 * an icmp packet. Note we can't always generate a meaningful 1356 * icmp message because icmp doesn't have a large enough repertoire 1357 * of codes and types. 1358 * 1359 * If not forwarding, just drop the packet. This could be confusing 1360 * if ipforwarding was zero but some routing protocol was advancing 1361 * us as a gateway to somewhere. However, we must let the routing 1362 * protocol deal with that. 1363 * 1364 * The srcrt parameter indicates whether the packet is being forwarded 1365 * via a source route. 1366 */ 1367 void 1368 ip_forward(struct mbuf *m, int srcrt) 1369 { 1370 struct ip *ip = mtod(m, struct ip *); 1371 struct in_ifaddr *ia; 1372 struct mbuf *mcopy; 1373 struct in_addr dest; 1374 struct route ro; 1375 int error, type = 0, code = 0, mtu = 0; 1376 1377 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1378 IPSTAT_INC(ips_cantforward); 1379 m_freem(m); 1380 return; 1381 } 1382 #ifdef IPSTEALTH 1383 if (!V_ipstealth) { 1384 #endif 1385 if (ip->ip_ttl <= IPTTLDEC) { 1386 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1387 0, 0); 1388 return; 1389 } 1390 #ifdef IPSTEALTH 1391 } 1392 #endif 1393 1394 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m)); 1395 #ifndef IPSEC 1396 /* 1397 * 'ia' may be NULL if there is no route for this destination. 1398 * In case of IPsec, Don't discard it just yet, but pass it to 1399 * ip_output in case of outgoing IPsec policy. 1400 */ 1401 if (!srcrt && ia == NULL) { 1402 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1403 return; 1404 } 1405 #endif 1406 1407 /* 1408 * Save the IP header and at most 8 bytes of the payload, 1409 * in case we need to generate an ICMP message to the src. 1410 * 1411 * XXX this can be optimized a lot by saving the data in a local 1412 * buffer on the stack (72 bytes at most), and only allocating the 1413 * mbuf if really necessary. The vast majority of the packets 1414 * are forwarded without having to send an ICMP back (either 1415 * because unnecessary, or because rate limited), so we are 1416 * really we are wasting a lot of work here. 1417 * 1418 * We don't use m_copy() because it might return a reference 1419 * to a shared cluster. Both this function and ip_output() 1420 * assume exclusive access to the IP header in `m', so any 1421 * data in a cluster may change before we reach icmp_error(). 1422 */ 1423 mcopy = m_gethdr(M_NOWAIT, m->m_type); 1424 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_NOWAIT)) { 1425 /* 1426 * It's probably ok if the pkthdr dup fails (because 1427 * the deep copy of the tag chain failed), but for now 1428 * be conservative and just discard the copy since 1429 * code below may some day want the tags. 1430 */ 1431 m_free(mcopy); 1432 mcopy = NULL; 1433 } 1434 if (mcopy != NULL) { 1435 mcopy->m_len = min(ntohs(ip->ip_len), M_TRAILINGSPACE(mcopy)); 1436 mcopy->m_pkthdr.len = mcopy->m_len; 1437 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1438 } 1439 1440 #ifdef IPSTEALTH 1441 if (!V_ipstealth) { 1442 #endif 1443 ip->ip_ttl -= IPTTLDEC; 1444 #ifdef IPSTEALTH 1445 } 1446 #endif 1447 1448 /* 1449 * If forwarding packet using same interface that it came in on, 1450 * perhaps should send a redirect to sender to shortcut a hop. 1451 * Only send redirect if source is sending directly to us, 1452 * and if packet was not source routed (or has any options). 1453 * Also, don't send redirect if forwarding using a default route 1454 * or a route modified by a redirect. 1455 */ 1456 dest.s_addr = 0; 1457 if (!srcrt && V_ipsendredirects && 1458 ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) { 1459 struct sockaddr_in *sin; 1460 struct rtentry *rt; 1461 1462 bzero(&ro, sizeof(ro)); 1463 sin = (struct sockaddr_in *)&ro.ro_dst; 1464 sin->sin_family = AF_INET; 1465 sin->sin_len = sizeof(*sin); 1466 sin->sin_addr = ip->ip_dst; 1467 in_rtalloc_ign(&ro, 0, M_GETFIB(m)); 1468 1469 rt = ro.ro_rt; 1470 1471 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1472 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1473 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1474 u_long src = ntohl(ip->ip_src.s_addr); 1475 1476 if (RTA(rt) && 1477 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1478 if (rt->rt_flags & RTF_GATEWAY) 1479 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1480 else 1481 dest.s_addr = ip->ip_dst.s_addr; 1482 /* Router requirements says to only send host redirects */ 1483 type = ICMP_REDIRECT; 1484 code = ICMP_REDIRECT_HOST; 1485 } 1486 } 1487 if (rt) 1488 RTFREE(rt); 1489 } 1490 1491 /* 1492 * Try to cache the route MTU from ip_output so we can consider it for 1493 * the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191. 1494 */ 1495 bzero(&ro, sizeof(ro)); 1496 1497 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL); 1498 1499 if (error == EMSGSIZE && ro.ro_rt) 1500 mtu = ro.ro_rt->rt_rmx.rmx_mtu; 1501 RO_RTFREE(&ro); 1502 1503 if (error) 1504 IPSTAT_INC(ips_cantforward); 1505 else { 1506 IPSTAT_INC(ips_forward); 1507 if (type) 1508 IPSTAT_INC(ips_redirectsent); 1509 else { 1510 if (mcopy) 1511 m_freem(mcopy); 1512 if (ia != NULL) 1513 ifa_free(&ia->ia_ifa); 1514 return; 1515 } 1516 } 1517 if (mcopy == NULL) { 1518 if (ia != NULL) 1519 ifa_free(&ia->ia_ifa); 1520 return; 1521 } 1522 1523 switch (error) { 1524 1525 case 0: /* forwarded, but need redirect */ 1526 /* type, code set above */ 1527 break; 1528 1529 case ENETUNREACH: 1530 case EHOSTUNREACH: 1531 case ENETDOWN: 1532 case EHOSTDOWN: 1533 default: 1534 type = ICMP_UNREACH; 1535 code = ICMP_UNREACH_HOST; 1536 break; 1537 1538 case EMSGSIZE: 1539 type = ICMP_UNREACH; 1540 code = ICMP_UNREACH_NEEDFRAG; 1541 1542 #ifdef IPSEC 1543 /* 1544 * If IPsec is configured for this path, 1545 * override any possibly mtu value set by ip_output. 1546 */ 1547 mtu = ip_ipsec_mtu(mcopy, mtu); 1548 #endif /* IPSEC */ 1549 /* 1550 * If the MTU was set before make sure we are below the 1551 * interface MTU. 1552 * If the MTU wasn't set before use the interface mtu or 1553 * fall back to the next smaller mtu step compared to the 1554 * current packet size. 1555 */ 1556 if (mtu != 0) { 1557 if (ia != NULL) 1558 mtu = min(mtu, ia->ia_ifp->if_mtu); 1559 } else { 1560 if (ia != NULL) 1561 mtu = ia->ia_ifp->if_mtu; 1562 else 1563 mtu = ip_next_mtu(ntohs(ip->ip_len), 0); 1564 } 1565 IPSTAT_INC(ips_cantfrag); 1566 break; 1567 1568 case ENOBUFS: 1569 /* 1570 * A router should not generate ICMP_SOURCEQUENCH as 1571 * required in RFC1812 Requirements for IP Version 4 Routers. 1572 * Source quench could be a big problem under DoS attacks, 1573 * or if the underlying interface is rate-limited. 1574 * Those who need source quench packets may re-enable them 1575 * via the net.inet.ip.sendsourcequench sysctl. 1576 */ 1577 if (V_ip_sendsourcequench == 0) { 1578 m_freem(mcopy); 1579 if (ia != NULL) 1580 ifa_free(&ia->ia_ifa); 1581 return; 1582 } else { 1583 type = ICMP_SOURCEQUENCH; 1584 code = 0; 1585 } 1586 break; 1587 1588 case EACCES: /* ipfw denied packet */ 1589 m_freem(mcopy); 1590 if (ia != NULL) 1591 ifa_free(&ia->ia_ifa); 1592 return; 1593 } 1594 if (ia != NULL) 1595 ifa_free(&ia->ia_ifa); 1596 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1597 } 1598 1599 void 1600 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1601 struct mbuf *m) 1602 { 1603 1604 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1605 struct bintime bt; 1606 1607 bintime(&bt); 1608 if (inp->inp_socket->so_options & SO_BINTIME) { 1609 *mp = sbcreatecontrol((caddr_t)&bt, sizeof(bt), 1610 SCM_BINTIME, SOL_SOCKET); 1611 if (*mp) 1612 mp = &(*mp)->m_next; 1613 } 1614 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1615 struct timeval tv; 1616 1617 bintime2timeval(&bt, &tv); 1618 *mp = sbcreatecontrol((caddr_t)&tv, sizeof(tv), 1619 SCM_TIMESTAMP, SOL_SOCKET); 1620 if (*mp) 1621 mp = &(*mp)->m_next; 1622 } 1623 } 1624 if (inp->inp_flags & INP_RECVDSTADDR) { 1625 *mp = sbcreatecontrol((caddr_t)&ip->ip_dst, 1626 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1627 if (*mp) 1628 mp = &(*mp)->m_next; 1629 } 1630 if (inp->inp_flags & INP_RECVTTL) { 1631 *mp = sbcreatecontrol((caddr_t)&ip->ip_ttl, 1632 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1633 if (*mp) 1634 mp = &(*mp)->m_next; 1635 } 1636 #ifdef notyet 1637 /* XXX 1638 * Moving these out of udp_input() made them even more broken 1639 * than they already were. 1640 */ 1641 /* options were tossed already */ 1642 if (inp->inp_flags & INP_RECVOPTS) { 1643 *mp = sbcreatecontrol((caddr_t)opts_deleted_above, 1644 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1645 if (*mp) 1646 mp = &(*mp)->m_next; 1647 } 1648 /* ip_srcroute doesn't do what we want here, need to fix */ 1649 if (inp->inp_flags & INP_RECVRETOPTS) { 1650 *mp = sbcreatecontrol((caddr_t)ip_srcroute(m), 1651 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1652 if (*mp) 1653 mp = &(*mp)->m_next; 1654 } 1655 #endif 1656 if (inp->inp_flags & INP_RECVIF) { 1657 struct ifnet *ifp; 1658 struct sdlbuf { 1659 struct sockaddr_dl sdl; 1660 u_char pad[32]; 1661 } sdlbuf; 1662 struct sockaddr_dl *sdp; 1663 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1664 1665 if ((ifp = m->m_pkthdr.rcvif) && 1666 ifp->if_index && ifp->if_index <= V_if_index) { 1667 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1668 /* 1669 * Change our mind and don't try copy. 1670 */ 1671 if (sdp->sdl_family != AF_LINK || 1672 sdp->sdl_len > sizeof(sdlbuf)) { 1673 goto makedummy; 1674 } 1675 bcopy(sdp, sdl2, sdp->sdl_len); 1676 } else { 1677 makedummy: 1678 sdl2->sdl_len = 1679 offsetof(struct sockaddr_dl, sdl_data[0]); 1680 sdl2->sdl_family = AF_LINK; 1681 sdl2->sdl_index = 0; 1682 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1683 } 1684 *mp = sbcreatecontrol((caddr_t)sdl2, sdl2->sdl_len, 1685 IP_RECVIF, IPPROTO_IP); 1686 if (*mp) 1687 mp = &(*mp)->m_next; 1688 } 1689 if (inp->inp_flags & INP_RECVTOS) { 1690 *mp = sbcreatecontrol((caddr_t)&ip->ip_tos, 1691 sizeof(u_char), IP_RECVTOS, IPPROTO_IP); 1692 if (*mp) 1693 mp = &(*mp)->m_next; 1694 } 1695 } 1696 1697 /* 1698 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the 1699 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on 1700 * locking. This code remains in ip_input.c as ip_mroute.c is optionally 1701 * compiled. 1702 */ 1703 static VNET_DEFINE(int, ip_rsvp_on); 1704 VNET_DEFINE(struct socket *, ip_rsvpd); 1705 1706 #define V_ip_rsvp_on VNET(ip_rsvp_on) 1707 1708 int 1709 ip_rsvp_init(struct socket *so) 1710 { 1711 1712 if (so->so_type != SOCK_RAW || 1713 so->so_proto->pr_protocol != IPPROTO_RSVP) 1714 return EOPNOTSUPP; 1715 1716 if (V_ip_rsvpd != NULL) 1717 return EADDRINUSE; 1718 1719 V_ip_rsvpd = so; 1720 /* 1721 * This may seem silly, but we need to be sure we don't over-increment 1722 * the RSVP counter, in case something slips up. 1723 */ 1724 if (!V_ip_rsvp_on) { 1725 V_ip_rsvp_on = 1; 1726 V_rsvp_on++; 1727 } 1728 1729 return 0; 1730 } 1731 1732 int 1733 ip_rsvp_done(void) 1734 { 1735 1736 V_ip_rsvpd = NULL; 1737 /* 1738 * This may seem silly, but we need to be sure we don't over-decrement 1739 * the RSVP counter, in case something slips up. 1740 */ 1741 if (V_ip_rsvp_on) { 1742 V_ip_rsvp_on = 0; 1743 V_rsvp_on--; 1744 } 1745 return 0; 1746 } 1747 1748 void 1749 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1750 { 1751 1752 if (rsvp_input_p) { /* call the real one if loaded */ 1753 rsvp_input_p(m, off); 1754 return; 1755 } 1756 1757 /* Can still get packets with rsvp_on = 0 if there is a local member 1758 * of the group to which the RSVP packet is addressed. But in this 1759 * case we want to throw the packet away. 1760 */ 1761 1762 if (!V_rsvp_on) { 1763 m_freem(m); 1764 return; 1765 } 1766 1767 if (V_ip_rsvpd != NULL) { 1768 rip_input(m, off); 1769 return; 1770 } 1771 /* Drop the packet */ 1772 m_freem(m); 1773 }
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