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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/8.1/sys/netinet/ip_input.c 207695 2010-05-06 06:44:19Z bz $"); 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 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_systm.h> 69 #include <netinet/in_var.h> 70 #include <netinet/ip.h> 71 #include <netinet/in_pcb.h> 72 #include <netinet/ip_var.h> 73 #include <netinet/ip_fw.h> 74 #include <netinet/ip_icmp.h> 75 #include <netinet/ip_options.h> 76 #include <machine/in_cksum.h> 77 #ifdef DEV_CARP 78 #include <netinet/ip_carp.h> 79 #endif 80 #ifdef IPSEC 81 #include <netinet/ip_ipsec.h> 82 #endif /* IPSEC */ 83 84 #include <sys/socketvar.h> 85 86 #include <security/mac/mac_framework.h> 87 88 #ifdef CTASSERT 89 CTASSERT(sizeof(struct ip) == 20); 90 #endif 91 92 struct rwlock in_ifaddr_lock; 93 RW_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock"); 94 95 VNET_DEFINE(int, rsvp_on); 96 97 VNET_DEFINE(int, ipforwarding); 98 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 99 &VNET_NAME(ipforwarding), 0, 100 "Enable IP forwarding between interfaces"); 101 102 static VNET_DEFINE(int, ipsendredirects) = 1; /* XXX */ 103 #define V_ipsendredirects VNET(ipsendredirects) 104 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 105 &VNET_NAME(ipsendredirects), 0, 106 "Enable sending IP redirects"); 107 108 VNET_DEFINE(int, ip_defttl) = IPDEFTTL; 109 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 110 &VNET_NAME(ip_defttl), 0, 111 "Maximum TTL on IP packets"); 112 113 static VNET_DEFINE(int, ip_keepfaith); 114 #define V_ip_keepfaith VNET(ip_keepfaith) 115 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 116 &VNET_NAME(ip_keepfaith), 0, 117 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 118 119 static VNET_DEFINE(int, ip_sendsourcequench); 120 #define V_ip_sendsourcequench VNET(ip_sendsourcequench) 121 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 122 &VNET_NAME(ip_sendsourcequench), 0, 123 "Enable the transmission of source quench packets"); 124 125 VNET_DEFINE(int, ip_do_randomid); 126 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 127 &VNET_NAME(ip_do_randomid), 0, 128 "Assign random ip_id values"); 129 130 /* 131 * XXX - Setting ip_checkinterface mostly implements the receive side of 132 * the Strong ES model described in RFC 1122, but since the routing table 133 * and transmit implementation do not implement the Strong ES model, 134 * setting this to 1 results in an odd hybrid. 135 * 136 * XXX - ip_checkinterface currently must be disabled if you use ipnat 137 * to translate the destination address to another local interface. 138 * 139 * XXX - ip_checkinterface must be disabled if you add IP aliases 140 * to the loopback interface instead of the interface where the 141 * packets for those addresses are received. 142 */ 143 static VNET_DEFINE(int, ip_checkinterface); 144 #define V_ip_checkinterface VNET(ip_checkinterface) 145 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 146 &VNET_NAME(ip_checkinterface), 0, 147 "Verify packet arrives on correct interface"); 148 149 VNET_DEFINE(struct pfil_head, inet_pfil_hook); /* Packet filter hooks */ 150 151 static struct netisr_handler ip_nh = { 152 .nh_name = "ip", 153 .nh_handler = ip_input, 154 .nh_proto = NETISR_IP, 155 .nh_policy = NETISR_POLICY_FLOW, 156 }; 157 158 extern struct domain inetdomain; 159 extern struct protosw inetsw[]; 160 u_char ip_protox[IPPROTO_MAX]; 161 VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */ 162 VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */ 163 VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */ 164 165 VNET_DEFINE(struct ipstat, ipstat); 166 SYSCTL_VNET_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 167 &VNET_NAME(ipstat), ipstat, 168 "IP statistics (struct ipstat, netinet/ip_var.h)"); 169 170 static VNET_DEFINE(uma_zone_t, ipq_zone); 171 static VNET_DEFINE(TAILQ_HEAD(ipqhead, ipq), ipq[IPREASS_NHASH]); 172 static struct mtx ipqlock; 173 174 #define V_ipq_zone VNET(ipq_zone) 175 #define V_ipq VNET(ipq) 176 177 #define IPQ_LOCK() mtx_lock(&ipqlock) 178 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 179 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 180 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 181 182 static void maxnipq_update(void); 183 static void ipq_zone_change(void *); 184 static void ip_drain_locked(void); 185 186 static VNET_DEFINE(int, maxnipq); /* Administrative limit on # reass queues. */ 187 static VNET_DEFINE(int, nipq); /* Total # of reass queues */ 188 #define V_maxnipq VNET(maxnipq) 189 #define V_nipq VNET(nipq) 190 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, 191 &VNET_NAME(nipq), 0, 192 "Current number of IPv4 fragment reassembly queue entries"); 193 194 static VNET_DEFINE(int, maxfragsperpacket); 195 #define V_maxfragsperpacket VNET(maxfragsperpacket) 196 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 197 &VNET_NAME(maxfragsperpacket), 0, 198 "Maximum number of IPv4 fragments allowed per packet"); 199 200 struct callout ipport_tick_callout; 201 202 #ifdef IPCTL_DEFMTU 203 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 204 &ip_mtu, 0, "Default MTU"); 205 #endif 206 207 #ifdef IPSTEALTH 208 VNET_DEFINE(int, ipstealth); 209 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 210 &VNET_NAME(ipstealth), 0, 211 "IP stealth mode, no TTL decrementation on forwarding"); 212 #endif 213 214 #ifdef FLOWTABLE 215 static VNET_DEFINE(int, ip_output_flowtable_size) = 2048; 216 VNET_DEFINE(struct flowtable *, ip_ft); 217 #define V_ip_output_flowtable_size VNET(ip_output_flowtable_size) 218 219 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, output_flowtable_size, CTLFLAG_RDTUN, 220 &VNET_NAME(ip_output_flowtable_size), 2048, 221 "number of entries in the per-cpu output flow caches"); 222 #endif 223 224 VNET_DEFINE(int, fw_one_pass) = 1; 225 226 static void ip_freef(struct ipqhead *, struct ipq *); 227 228 /* 229 * Kernel module interface for updating ipstat. The argument is an index 230 * into ipstat treated as an array of u_long. While this encodes the general 231 * layout of ipstat into the caller, it doesn't encode its location, so that 232 * future changes to add, for example, per-CPU stats support won't cause 233 * binary compatibility problems for kernel modules. 234 */ 235 void 236 kmod_ipstat_inc(int statnum) 237 { 238 239 (*((u_long *)&V_ipstat + statnum))++; 240 } 241 242 void 243 kmod_ipstat_dec(int statnum) 244 { 245 246 (*((u_long *)&V_ipstat + statnum))--; 247 } 248 249 static int 250 sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS) 251 { 252 int error, qlimit; 253 254 netisr_getqlimit(&ip_nh, &qlimit); 255 error = sysctl_handle_int(oidp, &qlimit, 0, req); 256 if (error || !req->newptr) 257 return (error); 258 if (qlimit < 1) 259 return (EINVAL); 260 return (netisr_setqlimit(&ip_nh, qlimit)); 261 } 262 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, 263 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I", 264 "Maximum size of the IP input queue"); 265 266 static int 267 sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS) 268 { 269 u_int64_t qdrops_long; 270 int error, qdrops; 271 272 netisr_getqdrops(&ip_nh, &qdrops_long); 273 qdrops = qdrops_long; 274 error = sysctl_handle_int(oidp, &qdrops, 0, req); 275 if (error || !req->newptr) 276 return (error); 277 if (qdrops != 0) 278 return (EINVAL); 279 netisr_clearqdrops(&ip_nh); 280 return (0); 281 } 282 283 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, 284 CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I", 285 "Number of packets dropped from the IP input queue"); 286 287 /* 288 * IP initialization: fill in IP protocol switch table. 289 * All protocols not implemented in kernel go to raw IP protocol handler. 290 */ 291 void 292 ip_init(void) 293 { 294 struct protosw *pr; 295 int i; 296 297 V_ip_id = time_second & 0xffff; 298 299 TAILQ_INIT(&V_in_ifaddrhead); 300 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask); 301 302 /* Initialize IP reassembly queue. */ 303 for (i = 0; i < IPREASS_NHASH; i++) 304 TAILQ_INIT(&V_ipq[i]); 305 V_maxnipq = nmbclusters / 32; 306 V_maxfragsperpacket = 16; 307 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 308 NULL, UMA_ALIGN_PTR, 0); 309 maxnipq_update(); 310 311 /* Initialize packet filter hooks. */ 312 V_inet_pfil_hook.ph_type = PFIL_TYPE_AF; 313 V_inet_pfil_hook.ph_af = AF_INET; 314 if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0) 315 printf("%s: WARNING: unable to register pfil hook, " 316 "error %d\n", __func__, i); 317 318 #ifdef FLOWTABLE 319 if (TUNABLE_INT_FETCH("net.inet.ip.output_flowtable_size", 320 &V_ip_output_flowtable_size)) { 321 if (V_ip_output_flowtable_size < 256) 322 V_ip_output_flowtable_size = 256; 323 if (!powerof2(V_ip_output_flowtable_size)) { 324 printf("flowtable must be power of 2 size\n"); 325 V_ip_output_flowtable_size = 2048; 326 } 327 } else { 328 /* 329 * round up to the next power of 2 330 */ 331 V_ip_output_flowtable_size = 1 << fls((1024 + maxusers * 64)-1); 332 } 333 V_ip_ft = flowtable_alloc("ipv4", V_ip_output_flowtable_size, FL_PCPU); 334 #endif 335 336 /* Skip initialization of globals for non-default instances. */ 337 if (!IS_DEFAULT_VNET(curvnet)) 338 return; 339 340 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 341 if (pr == NULL) 342 panic("ip_init: PF_INET not found"); 343 344 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 345 for (i = 0; i < IPPROTO_MAX; i++) 346 ip_protox[i] = pr - inetsw; 347 /* 348 * Cycle through IP protocols and put them into the appropriate place 349 * in ip_protox[]. 350 */ 351 for (pr = inetdomain.dom_protosw; 352 pr < inetdomain.dom_protoswNPROTOSW; pr++) 353 if (pr->pr_domain->dom_family == PF_INET && 354 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 355 /* Be careful to only index valid IP protocols. */ 356 if (pr->pr_protocol < IPPROTO_MAX) 357 ip_protox[pr->pr_protocol] = pr - inetsw; 358 } 359 360 /* Start ipport_tick. */ 361 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE); 362 callout_reset(&ipport_tick_callout, 1, ipport_tick, NULL); 363 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL, 364 SHUTDOWN_PRI_DEFAULT); 365 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, 366 NULL, EVENTHANDLER_PRI_ANY); 367 368 /* Initialize various other remaining things. */ 369 IPQ_LOCK_INIT(); 370 netisr_register(&ip_nh); 371 } 372 373 #ifdef VIMAGE 374 void 375 ip_destroy(void) 376 { 377 378 /* Cleanup in_ifaddr hash table; should be empty. */ 379 hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask); 380 381 IPQ_LOCK(); 382 ip_drain_locked(); 383 IPQ_UNLOCK(); 384 385 uma_zdestroy(V_ipq_zone); 386 } 387 #endif 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 struct ip *ip = NULL; 404 struct in_ifaddr *ia = NULL; 405 struct ifaddr *ifa; 406 struct ifnet *ifp; 407 int checkif, hlen = 0; 408 u_short sum; 409 int dchg = 0; /* dest changed after fw */ 410 struct in_addr odst; /* original dst address */ 411 412 M_ASSERTPKTHDR(m); 413 414 if (m->m_flags & M_FASTFWD_OURS) { 415 /* 416 * Firewall or NAT changed destination to local. 417 * We expect ip_len and ip_off to be in host byte order. 418 */ 419 m->m_flags &= ~M_FASTFWD_OURS; 420 /* Set up some basics that will be used later. */ 421 ip = mtod(m, struct ip *); 422 hlen = ip->ip_hl << 2; 423 goto ours; 424 } 425 426 IPSTAT_INC(ips_total); 427 428 if (m->m_pkthdr.len < sizeof(struct ip)) 429 goto tooshort; 430 431 if (m->m_len < sizeof (struct ip) && 432 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 433 IPSTAT_INC(ips_toosmall); 434 return; 435 } 436 ip = mtod(m, struct ip *); 437 438 if (ip->ip_v != IPVERSION) { 439 IPSTAT_INC(ips_badvers); 440 goto bad; 441 } 442 443 hlen = ip->ip_hl << 2; 444 if (hlen < sizeof(struct ip)) { /* minimum header length */ 445 IPSTAT_INC(ips_badhlen); 446 goto bad; 447 } 448 if (hlen > m->m_len) { 449 if ((m = m_pullup(m, hlen)) == NULL) { 450 IPSTAT_INC(ips_badhlen); 451 return; 452 } 453 ip = mtod(m, struct ip *); 454 } 455 456 /* 127/8 must not appear on wire - RFC1122 */ 457 ifp = m->m_pkthdr.rcvif; 458 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 459 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 460 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 461 IPSTAT_INC(ips_badaddr); 462 goto bad; 463 } 464 } 465 466 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 467 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 468 } else { 469 if (hlen == sizeof(struct ip)) { 470 sum = in_cksum_hdr(ip); 471 } else { 472 sum = in_cksum(m, hlen); 473 } 474 } 475 if (sum) { 476 IPSTAT_INC(ips_badsum); 477 goto bad; 478 } 479 480 #ifdef ALTQ 481 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 482 /* packet is dropped by traffic conditioner */ 483 return; 484 #endif 485 486 /* 487 * Convert fields to host representation. 488 */ 489 ip->ip_len = ntohs(ip->ip_len); 490 if (ip->ip_len < hlen) { 491 IPSTAT_INC(ips_badlen); 492 goto bad; 493 } 494 ip->ip_off = ntohs(ip->ip_off); 495 496 /* 497 * Check that the amount of data in the buffers 498 * is as at least much as the IP header would have us expect. 499 * Trim mbufs if longer than we expect. 500 * Drop packet if shorter than we expect. 501 */ 502 if (m->m_pkthdr.len < ip->ip_len) { 503 tooshort: 504 IPSTAT_INC(ips_tooshort); 505 goto bad; 506 } 507 if (m->m_pkthdr.len > ip->ip_len) { 508 if (m->m_len == m->m_pkthdr.len) { 509 m->m_len = ip->ip_len; 510 m->m_pkthdr.len = ip->ip_len; 511 } else 512 m_adj(m, ip->ip_len - m->m_pkthdr.len); 513 } 514 #ifdef IPSEC 515 /* 516 * Bypass packet filtering for packets from a tunnel (gif). 517 */ 518 if (ip_ipsec_filtertunnel(m)) 519 goto passin; 520 #endif /* IPSEC */ 521 522 /* 523 * Run through list of hooks for input packets. 524 * 525 * NB: Beware of the destination address changing (e.g. 526 * by NAT rewriting). When this happens, tell 527 * ip_forward to do the right thing. 528 */ 529 530 /* Jump over all PFIL processing if hooks are not active. */ 531 if (!PFIL_HOOKED(&V_inet_pfil_hook)) 532 goto passin; 533 534 odst = ip->ip_dst; 535 if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0) 536 return; 537 if (m == NULL) /* consumed by filter */ 538 return; 539 540 ip = mtod(m, struct ip *); 541 dchg = (odst.s_addr != ip->ip_dst.s_addr); 542 ifp = m->m_pkthdr.rcvif; 543 544 #ifdef IPFIREWALL_FORWARD 545 if (m->m_flags & M_FASTFWD_OURS) { 546 m->m_flags &= ~M_FASTFWD_OURS; 547 goto ours; 548 } 549 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 550 /* 551 * Directly ship the packet on. This allows forwarding 552 * packets originally destined to us to some other directly 553 * connected host. 554 */ 555 ip_forward(m, dchg); 556 return; 557 } 558 #endif /* IPFIREWALL_FORWARD */ 559 560 passin: 561 /* 562 * Process options and, if not destined for us, 563 * ship it on. ip_dooptions returns 1 when an 564 * error was detected (causing an icmp message 565 * to be sent and the original packet to be freed). 566 */ 567 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 568 return; 569 570 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 571 * matter if it is destined to another node, or whether it is 572 * a multicast one, RSVP wants it! and prevents it from being forwarded 573 * anywhere else. Also checks if the rsvp daemon is running before 574 * grabbing the packet. 575 */ 576 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP) 577 goto ours; 578 579 /* 580 * Check our list of addresses, to see if the packet is for us. 581 * If we don't have any addresses, assume any unicast packet 582 * we receive might be for us (and let the upper layers deal 583 * with it). 584 */ 585 if (TAILQ_EMPTY(&V_in_ifaddrhead) && 586 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 587 goto ours; 588 589 /* 590 * Enable a consistency check between the destination address 591 * and the arrival interface for a unicast packet (the RFC 1122 592 * strong ES model) if IP forwarding is disabled and the packet 593 * is not locally generated and the packet is not subject to 594 * 'ipfw fwd'. 595 * 596 * XXX - Checking also should be disabled if the destination 597 * address is ipnat'ed to a different interface. 598 * 599 * XXX - Checking is incompatible with IP aliases added 600 * to the loopback interface instead of the interface where 601 * the packets are received. 602 * 603 * XXX - This is the case for carp vhost IPs as well so we 604 * insert a workaround. If the packet got here, we already 605 * checked with carp_iamatch() and carp_forus(). 606 */ 607 checkif = V_ip_checkinterface && (V_ipforwarding == 0) && 608 ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) && 609 #ifdef DEV_CARP 610 !ifp->if_carp && 611 #endif 612 (dchg == 0); 613 614 /* 615 * Check for exact addresses in the hash bucket. 616 */ 617 /* IN_IFADDR_RLOCK(); */ 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 ifa_ref(&ia->ia_ifa); 627 /* IN_IFADDR_RUNLOCK(); */ 628 goto ours; 629 } 630 } 631 /* IN_IFADDR_RUNLOCK(); */ 632 633 /* 634 * Check for broadcast addresses. 635 * 636 * Only accept broadcast packets that arrive via the matching 637 * interface. Reception of forwarded directed broadcasts would 638 * be handled via ip_forward() and ether_output() with the loopback 639 * into the stack for SIMPLEX interfaces handled by ether_output(). 640 */ 641 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) { 642 IF_ADDR_LOCK(ifp); 643 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 644 if (ifa->ifa_addr->sa_family != AF_INET) 645 continue; 646 ia = ifatoia(ifa); 647 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 648 ip->ip_dst.s_addr) { 649 ifa_ref(ifa); 650 IF_ADDR_UNLOCK(ifp); 651 goto ours; 652 } 653 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) { 654 ifa_ref(ifa); 655 IF_ADDR_UNLOCK(ifp); 656 goto ours; 657 } 658 #ifdef BOOTP_COMPAT 659 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) { 660 ifa_ref(ifa); 661 IF_ADDR_UNLOCK(ifp); 662 goto ours; 663 } 664 #endif 665 } 666 IF_ADDR_UNLOCK(ifp); 667 ia = NULL; 668 } 669 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */ 670 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) { 671 IPSTAT_INC(ips_cantforward); 672 m_freem(m); 673 return; 674 } 675 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 676 if (V_ip_mrouter) { 677 /* 678 * If we are acting as a multicast router, all 679 * incoming multicast packets are passed to the 680 * kernel-level multicast forwarding function. 681 * The packet is returned (relatively) intact; if 682 * ip_mforward() returns a non-zero value, the packet 683 * must be discarded, else it may be accepted below. 684 */ 685 if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) { 686 IPSTAT_INC(ips_cantforward); 687 m_freem(m); 688 return; 689 } 690 691 /* 692 * The process-level routing daemon needs to receive 693 * all multicast IGMP packets, whether or not this 694 * host belongs to their destination groups. 695 */ 696 if (ip->ip_p == IPPROTO_IGMP) 697 goto ours; 698 IPSTAT_INC(ips_forward); 699 } 700 /* 701 * Assume the packet is for us, to avoid prematurely taking 702 * a lock on the in_multi hash. Protocols must perform 703 * their own filtering and update statistics accordingly. 704 */ 705 goto ours; 706 } 707 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 708 goto ours; 709 if (ip->ip_dst.s_addr == INADDR_ANY) 710 goto ours; 711 712 /* 713 * FAITH(Firewall Aided Internet Translator) 714 */ 715 if (ifp && ifp->if_type == IFT_FAITH) { 716 if (V_ip_keepfaith) { 717 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 718 goto ours; 719 } 720 m_freem(m); 721 return; 722 } 723 724 /* 725 * Not for us; forward if possible and desirable. 726 */ 727 if (V_ipforwarding == 0) { 728 IPSTAT_INC(ips_cantforward); 729 m_freem(m); 730 } else { 731 #ifdef IPSEC 732 if (ip_ipsec_fwd(m)) 733 goto bad; 734 #endif /* IPSEC */ 735 ip_forward(m, dchg); 736 } 737 return; 738 739 ours: 740 #ifdef IPSTEALTH 741 /* 742 * IPSTEALTH: Process non-routing options only 743 * if the packet is destined for us. 744 */ 745 if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1)) { 746 if (ia != NULL) 747 ifa_free(&ia->ia_ifa); 748 return; 749 } 750 #endif /* IPSTEALTH */ 751 752 /* Count the packet in the ip address stats */ 753 if (ia != NULL) { 754 ia->ia_ifa.if_ipackets++; 755 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 756 ifa_free(&ia->ia_ifa); 757 } 758 759 /* 760 * Attempt reassembly; if it succeeds, proceed. 761 * ip_reass() will return a different mbuf. 762 */ 763 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 764 m = ip_reass(m); 765 if (m == NULL) 766 return; 767 ip = mtod(m, struct ip *); 768 /* Get the header length of the reassembled packet */ 769 hlen = ip->ip_hl << 2; 770 } 771 772 /* 773 * Further protocols expect the packet length to be w/o the 774 * IP header. 775 */ 776 ip->ip_len -= hlen; 777 778 #ifdef IPSEC 779 /* 780 * enforce IPsec policy checking if we are seeing last header. 781 * note that we do not visit this with protocols with pcb layer 782 * code - like udp/tcp/raw ip. 783 */ 784 if (ip_ipsec_input(m)) 785 goto bad; 786 #endif /* IPSEC */ 787 788 /* 789 * Switch out to protocol's input routine. 790 */ 791 IPSTAT_INC(ips_delivered); 792 793 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 794 return; 795 bad: 796 m_freem(m); 797 } 798 799 /* 800 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 801 * max has slightly different semantics than the sysctl, for historical 802 * reasons. 803 */ 804 static void 805 maxnipq_update(void) 806 { 807 808 /* 809 * -1 for unlimited allocation. 810 */ 811 if (V_maxnipq < 0) 812 uma_zone_set_max(V_ipq_zone, 0); 813 /* 814 * Positive number for specific bound. 815 */ 816 if (V_maxnipq > 0) 817 uma_zone_set_max(V_ipq_zone, V_maxnipq); 818 /* 819 * Zero specifies no further fragment queue allocation -- set the 820 * bound very low, but rely on implementation elsewhere to actually 821 * prevent allocation and reclaim current queues. 822 */ 823 if (V_maxnipq == 0) 824 uma_zone_set_max(V_ipq_zone, 1); 825 } 826 827 static void 828 ipq_zone_change(void *tag) 829 { 830 831 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) { 832 V_maxnipq = nmbclusters / 32; 833 maxnipq_update(); 834 } 835 } 836 837 static int 838 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 839 { 840 int error, i; 841 842 i = V_maxnipq; 843 error = sysctl_handle_int(oidp, &i, 0, req); 844 if (error || !req->newptr) 845 return (error); 846 847 /* 848 * XXXRW: Might be a good idea to sanity check the argument and place 849 * an extreme upper bound. 850 */ 851 if (i < -1) 852 return (EINVAL); 853 V_maxnipq = i; 854 maxnipq_update(); 855 return (0); 856 } 857 858 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 859 NULL, 0, sysctl_maxnipq, "I", 860 "Maximum number of IPv4 fragment reassembly queue entries"); 861 862 /* 863 * Take incoming datagram fragment and try to reassemble it into 864 * whole datagram. If the argument is the first fragment or one 865 * in between the function will return NULL and store the mbuf 866 * in the fragment chain. If the argument is the last fragment 867 * the packet will be reassembled and the pointer to the new 868 * mbuf returned for further processing. Only m_tags attached 869 * to the first packet/fragment are preserved. 870 * The IP header is *NOT* adjusted out of iplen. 871 */ 872 struct mbuf * 873 ip_reass(struct mbuf *m) 874 { 875 struct ip *ip; 876 struct mbuf *p, *q, *nq, *t; 877 struct ipq *fp = NULL; 878 struct ipqhead *head; 879 int i, hlen, next; 880 u_int8_t ecn, ecn0; 881 u_short hash; 882 883 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 884 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) { 885 IPSTAT_INC(ips_fragments); 886 IPSTAT_INC(ips_fragdropped); 887 m_freem(m); 888 return (NULL); 889 } 890 891 ip = mtod(m, struct ip *); 892 hlen = ip->ip_hl << 2; 893 894 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 895 head = &V_ipq[hash]; 896 IPQ_LOCK(); 897 898 /* 899 * Look for queue of fragments 900 * of this datagram. 901 */ 902 TAILQ_FOREACH(fp, head, ipq_list) 903 if (ip->ip_id == fp->ipq_id && 904 ip->ip_src.s_addr == fp->ipq_src.s_addr && 905 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 906 #ifdef MAC 907 mac_ipq_match(m, fp) && 908 #endif 909 ip->ip_p == fp->ipq_p) 910 goto found; 911 912 fp = NULL; 913 914 /* 915 * Attempt to trim the number of allocated fragment queues if it 916 * exceeds the administrative limit. 917 */ 918 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) { 919 /* 920 * drop something from the tail of the current queue 921 * before proceeding further 922 */ 923 struct ipq *q = TAILQ_LAST(head, ipqhead); 924 if (q == NULL) { /* gak */ 925 for (i = 0; i < IPREASS_NHASH; i++) { 926 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead); 927 if (r) { 928 IPSTAT_ADD(ips_fragtimeout, 929 r->ipq_nfrags); 930 ip_freef(&V_ipq[i], r); 931 break; 932 } 933 } 934 } else { 935 IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags); 936 ip_freef(head, q); 937 } 938 } 939 940 found: 941 /* 942 * Adjust ip_len to not reflect header, 943 * convert offset of this to bytes. 944 */ 945 ip->ip_len -= hlen; 946 if (ip->ip_off & IP_MF) { 947 /* 948 * Make sure that fragments have a data length 949 * that's a non-zero multiple of 8 bytes. 950 */ 951 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 952 IPSTAT_INC(ips_toosmall); /* XXX */ 953 goto dropfrag; 954 } 955 m->m_flags |= M_FRAG; 956 } else 957 m->m_flags &= ~M_FRAG; 958 ip->ip_off <<= 3; 959 960 961 /* 962 * Attempt reassembly; if it succeeds, proceed. 963 * ip_reass() will return a different mbuf. 964 */ 965 IPSTAT_INC(ips_fragments); 966 m->m_pkthdr.header = ip; 967 968 /* Previous ip_reass() started here. */ 969 /* 970 * Presence of header sizes in mbufs 971 * would confuse code below. 972 */ 973 m->m_data += hlen; 974 m->m_len -= hlen; 975 976 /* 977 * If first fragment to arrive, create a reassembly queue. 978 */ 979 if (fp == NULL) { 980 fp = uma_zalloc(V_ipq_zone, M_NOWAIT); 981 if (fp == NULL) 982 goto dropfrag; 983 #ifdef MAC 984 if (mac_ipq_init(fp, M_NOWAIT) != 0) { 985 uma_zfree(V_ipq_zone, fp); 986 fp = NULL; 987 goto dropfrag; 988 } 989 mac_ipq_create(m, fp); 990 #endif 991 TAILQ_INSERT_HEAD(head, fp, ipq_list); 992 V_nipq++; 993 fp->ipq_nfrags = 1; 994 fp->ipq_ttl = IPFRAGTTL; 995 fp->ipq_p = ip->ip_p; 996 fp->ipq_id = ip->ip_id; 997 fp->ipq_src = ip->ip_src; 998 fp->ipq_dst = ip->ip_dst; 999 fp->ipq_frags = m; 1000 m->m_nextpkt = NULL; 1001 goto done; 1002 } else { 1003 fp->ipq_nfrags++; 1004 #ifdef MAC 1005 mac_ipq_update(m, fp); 1006 #endif 1007 } 1008 1009 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1010 1011 /* 1012 * Handle ECN by comparing this segment with the first one; 1013 * if CE is set, do not lose CE. 1014 * drop if CE and not-ECT are mixed for the same packet. 1015 */ 1016 ecn = ip->ip_tos & IPTOS_ECN_MASK; 1017 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 1018 if (ecn == IPTOS_ECN_CE) { 1019 if (ecn0 == IPTOS_ECN_NOTECT) 1020 goto dropfrag; 1021 if (ecn0 != IPTOS_ECN_CE) 1022 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 1023 } 1024 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 1025 goto dropfrag; 1026 1027 /* 1028 * Find a segment which begins after this one does. 1029 */ 1030 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1031 if (GETIP(q)->ip_off > ip->ip_off) 1032 break; 1033 1034 /* 1035 * If there is a preceding segment, it may provide some of 1036 * our data already. If so, drop the data from the incoming 1037 * segment. If it provides all of our data, drop us, otherwise 1038 * stick new segment in the proper place. 1039 * 1040 * If some of the data is dropped from the the preceding 1041 * segment, then it's checksum is invalidated. 1042 */ 1043 if (p) { 1044 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1045 if (i > 0) { 1046 if (i >= ip->ip_len) 1047 goto dropfrag; 1048 m_adj(m, i); 1049 m->m_pkthdr.csum_flags = 0; 1050 ip->ip_off += i; 1051 ip->ip_len -= i; 1052 } 1053 m->m_nextpkt = p->m_nextpkt; 1054 p->m_nextpkt = m; 1055 } else { 1056 m->m_nextpkt = fp->ipq_frags; 1057 fp->ipq_frags = m; 1058 } 1059 1060 /* 1061 * While we overlap succeeding segments trim them or, 1062 * if they are completely covered, dequeue them. 1063 */ 1064 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1065 q = nq) { 1066 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1067 if (i < GETIP(q)->ip_len) { 1068 GETIP(q)->ip_len -= i; 1069 GETIP(q)->ip_off += i; 1070 m_adj(q, i); 1071 q->m_pkthdr.csum_flags = 0; 1072 break; 1073 } 1074 nq = q->m_nextpkt; 1075 m->m_nextpkt = nq; 1076 IPSTAT_INC(ips_fragdropped); 1077 fp->ipq_nfrags--; 1078 m_freem(q); 1079 } 1080 1081 /* 1082 * Check for complete reassembly and perform frag per packet 1083 * limiting. 1084 * 1085 * Frag limiting is performed here so that the nth frag has 1086 * a chance to complete the packet before we drop the packet. 1087 * As a result, n+1 frags are actually allowed per packet, but 1088 * only n will ever be stored. (n = maxfragsperpacket.) 1089 * 1090 */ 1091 next = 0; 1092 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1093 if (GETIP(q)->ip_off != next) { 1094 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1095 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1096 ip_freef(head, fp); 1097 } 1098 goto done; 1099 } 1100 next += GETIP(q)->ip_len; 1101 } 1102 /* Make sure the last packet didn't have the IP_MF flag */ 1103 if (p->m_flags & M_FRAG) { 1104 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1105 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1106 ip_freef(head, fp); 1107 } 1108 goto done; 1109 } 1110 1111 /* 1112 * Reassembly is complete. Make sure the packet is a sane size. 1113 */ 1114 q = fp->ipq_frags; 1115 ip = GETIP(q); 1116 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1117 IPSTAT_INC(ips_toolong); 1118 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1119 ip_freef(head, fp); 1120 goto done; 1121 } 1122 1123 /* 1124 * Concatenate fragments. 1125 */ 1126 m = q; 1127 t = m->m_next; 1128 m->m_next = NULL; 1129 m_cat(m, t); 1130 nq = q->m_nextpkt; 1131 q->m_nextpkt = NULL; 1132 for (q = nq; q != NULL; q = nq) { 1133 nq = q->m_nextpkt; 1134 q->m_nextpkt = NULL; 1135 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1136 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1137 m_cat(m, q); 1138 } 1139 /* 1140 * In order to do checksumming faster we do 'end-around carry' here 1141 * (and not in for{} loop), though it implies we are not going to 1142 * reassemble more than 64k fragments. 1143 */ 1144 m->m_pkthdr.csum_data = 1145 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1146 #ifdef MAC 1147 mac_ipq_reassemble(fp, m); 1148 mac_ipq_destroy(fp); 1149 #endif 1150 1151 /* 1152 * Create header for new ip packet by modifying header of first 1153 * packet; dequeue and discard fragment reassembly header. 1154 * Make header visible. 1155 */ 1156 ip->ip_len = (ip->ip_hl << 2) + next; 1157 ip->ip_src = fp->ipq_src; 1158 ip->ip_dst = fp->ipq_dst; 1159 TAILQ_REMOVE(head, fp, ipq_list); 1160 V_nipq--; 1161 uma_zfree(V_ipq_zone, fp); 1162 m->m_len += (ip->ip_hl << 2); 1163 m->m_data -= (ip->ip_hl << 2); 1164 /* some debugging cruft by sklower, below, will go away soon */ 1165 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1166 m_fixhdr(m); 1167 IPSTAT_INC(ips_reassembled); 1168 IPQ_UNLOCK(); 1169 return (m); 1170 1171 dropfrag: 1172 IPSTAT_INC(ips_fragdropped); 1173 if (fp != NULL) 1174 fp->ipq_nfrags--; 1175 m_freem(m); 1176 done: 1177 IPQ_UNLOCK(); 1178 return (NULL); 1179 1180 #undef GETIP 1181 } 1182 1183 /* 1184 * Free a fragment reassembly header and all 1185 * associated datagrams. 1186 */ 1187 static void 1188 ip_freef(struct ipqhead *fhp, struct ipq *fp) 1189 { 1190 struct mbuf *q; 1191 1192 IPQ_LOCK_ASSERT(); 1193 1194 while (fp->ipq_frags) { 1195 q = fp->ipq_frags; 1196 fp->ipq_frags = q->m_nextpkt; 1197 m_freem(q); 1198 } 1199 TAILQ_REMOVE(fhp, fp, ipq_list); 1200 uma_zfree(V_ipq_zone, fp); 1201 V_nipq--; 1202 } 1203 1204 /* 1205 * IP timer processing; 1206 * if a timer expires on a reassembly 1207 * queue, discard it. 1208 */ 1209 void 1210 ip_slowtimo(void) 1211 { 1212 VNET_ITERATOR_DECL(vnet_iter); 1213 struct ipq *fp; 1214 int i; 1215 1216 VNET_LIST_RLOCK_NOSLEEP(); 1217 IPQ_LOCK(); 1218 VNET_FOREACH(vnet_iter) { 1219 CURVNET_SET(vnet_iter); 1220 for (i = 0; i < IPREASS_NHASH; i++) { 1221 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) { 1222 struct ipq *fpp; 1223 1224 fpp = fp; 1225 fp = TAILQ_NEXT(fp, ipq_list); 1226 if(--fpp->ipq_ttl == 0) { 1227 IPSTAT_ADD(ips_fragtimeout, 1228 fpp->ipq_nfrags); 1229 ip_freef(&V_ipq[i], fpp); 1230 } 1231 } 1232 } 1233 /* 1234 * If we are over the maximum number of fragments 1235 * (due to the limit being lowered), drain off 1236 * enough to get down to the new limit. 1237 */ 1238 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) { 1239 for (i = 0; i < IPREASS_NHASH; i++) { 1240 while (V_nipq > V_maxnipq && 1241 !TAILQ_EMPTY(&V_ipq[i])) { 1242 IPSTAT_ADD(ips_fragdropped, 1243 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1244 ip_freef(&V_ipq[i], 1245 TAILQ_FIRST(&V_ipq[i])); 1246 } 1247 } 1248 } 1249 CURVNET_RESTORE(); 1250 } 1251 IPQ_UNLOCK(); 1252 VNET_LIST_RUNLOCK_NOSLEEP(); 1253 } 1254 1255 /* 1256 * Drain off all datagram fragments. 1257 */ 1258 static void 1259 ip_drain_locked(void) 1260 { 1261 int i; 1262 1263 IPQ_LOCK_ASSERT(); 1264 1265 for (i = 0; i < IPREASS_NHASH; i++) { 1266 while(!TAILQ_EMPTY(&V_ipq[i])) { 1267 IPSTAT_ADD(ips_fragdropped, 1268 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1269 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i])); 1270 } 1271 } 1272 } 1273 1274 void 1275 ip_drain(void) 1276 { 1277 VNET_ITERATOR_DECL(vnet_iter); 1278 1279 VNET_LIST_RLOCK_NOSLEEP(); 1280 IPQ_LOCK(); 1281 VNET_FOREACH(vnet_iter) { 1282 CURVNET_SET(vnet_iter); 1283 ip_drain_locked(); 1284 CURVNET_RESTORE(); 1285 } 1286 IPQ_UNLOCK(); 1287 VNET_LIST_RUNLOCK_NOSLEEP(); 1288 in_rtqdrain(); 1289 } 1290 1291 /* 1292 * The protocol to be inserted into ip_protox[] must be already registered 1293 * in inetsw[], either statically or through pf_proto_register(). 1294 */ 1295 int 1296 ipproto_register(u_char ipproto) 1297 { 1298 struct protosw *pr; 1299 1300 /* Sanity checks. */ 1301 if (ipproto == 0) 1302 return (EPROTONOSUPPORT); 1303 1304 /* 1305 * The protocol slot must not be occupied by another protocol 1306 * already. An index pointing to IPPROTO_RAW is unused. 1307 */ 1308 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1309 if (pr == NULL) 1310 return (EPFNOSUPPORT); 1311 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1312 return (EEXIST); 1313 1314 /* Find the protocol position in inetsw[] and set the index. */ 1315 for (pr = inetdomain.dom_protosw; 1316 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1317 if (pr->pr_domain->dom_family == PF_INET && 1318 pr->pr_protocol && pr->pr_protocol == ipproto) { 1319 /* Be careful to only index valid IP protocols. */ 1320 if (pr->pr_protocol < IPPROTO_MAX) { 1321 ip_protox[pr->pr_protocol] = pr - inetsw; 1322 return (0); 1323 } else 1324 return (EINVAL); 1325 } 1326 } 1327 return (EPROTONOSUPPORT); 1328 } 1329 1330 int 1331 ipproto_unregister(u_char ipproto) 1332 { 1333 struct protosw *pr; 1334 1335 /* Sanity checks. */ 1336 if (ipproto == 0) 1337 return (EPROTONOSUPPORT); 1338 1339 /* Check if the protocol was indeed registered. */ 1340 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1341 if (pr == NULL) 1342 return (EPFNOSUPPORT); 1343 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1344 return (ENOENT); 1345 1346 /* Reset the protocol slot to IPPROTO_RAW. */ 1347 ip_protox[ipproto] = pr - inetsw; 1348 return (0); 1349 } 1350 1351 /* 1352 * Given address of next destination (final or next hop), return (referenced) 1353 * internet address info of interface to be used to get there. 1354 */ 1355 struct in_ifaddr * 1356 ip_rtaddr(struct in_addr dst, u_int fibnum) 1357 { 1358 struct route sro; 1359 struct sockaddr_in *sin; 1360 struct in_ifaddr *ia; 1361 1362 bzero(&sro, sizeof(sro)); 1363 sin = (struct sockaddr_in *)&sro.ro_dst; 1364 sin->sin_family = AF_INET; 1365 sin->sin_len = sizeof(*sin); 1366 sin->sin_addr = dst; 1367 in_rtalloc_ign(&sro, 0, fibnum); 1368 1369 if (sro.ro_rt == NULL) 1370 return (NULL); 1371 1372 ia = ifatoia(sro.ro_rt->rt_ifa); 1373 ifa_ref(&ia->ia_ifa); 1374 RTFREE(sro.ro_rt); 1375 return (ia); 1376 } 1377 1378 u_char inetctlerrmap[PRC_NCMDS] = { 1379 0, 0, 0, 0, 1380 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1381 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1382 EMSGSIZE, EHOSTUNREACH, 0, 0, 1383 0, 0, EHOSTUNREACH, 0, 1384 ENOPROTOOPT, ECONNREFUSED 1385 }; 1386 1387 /* 1388 * Forward a packet. If some error occurs return the sender 1389 * an icmp packet. Note we can't always generate a meaningful 1390 * icmp message because icmp doesn't have a large enough repertoire 1391 * of codes and types. 1392 * 1393 * If not forwarding, just drop the packet. This could be confusing 1394 * if ipforwarding was zero but some routing protocol was advancing 1395 * us as a gateway to somewhere. However, we must let the routing 1396 * protocol deal with that. 1397 * 1398 * The srcrt parameter indicates whether the packet is being forwarded 1399 * via a source route. 1400 */ 1401 void 1402 ip_forward(struct mbuf *m, int srcrt) 1403 { 1404 struct ip *ip = mtod(m, struct ip *); 1405 struct in_ifaddr *ia; 1406 struct mbuf *mcopy; 1407 struct in_addr dest; 1408 struct route ro; 1409 int error, type = 0, code = 0, mtu = 0; 1410 1411 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1412 IPSTAT_INC(ips_cantforward); 1413 m_freem(m); 1414 return; 1415 } 1416 #ifdef IPSTEALTH 1417 if (!V_ipstealth) { 1418 #endif 1419 if (ip->ip_ttl <= IPTTLDEC) { 1420 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1421 0, 0); 1422 return; 1423 } 1424 #ifdef IPSTEALTH 1425 } 1426 #endif 1427 1428 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m)); 1429 #ifndef IPSEC 1430 /* 1431 * 'ia' may be NULL if there is no route for this destination. 1432 * In case of IPsec, Don't discard it just yet, but pass it to 1433 * ip_output in case of outgoing IPsec policy. 1434 */ 1435 if (!srcrt && ia == NULL) { 1436 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1437 return; 1438 } 1439 #endif 1440 1441 /* 1442 * Save the IP header and at most 8 bytes of the payload, 1443 * in case we need to generate an ICMP message to the src. 1444 * 1445 * XXX this can be optimized a lot by saving the data in a local 1446 * buffer on the stack (72 bytes at most), and only allocating the 1447 * mbuf if really necessary. The vast majority of the packets 1448 * are forwarded without having to send an ICMP back (either 1449 * because unnecessary, or because rate limited), so we are 1450 * really we are wasting a lot of work here. 1451 * 1452 * We don't use m_copy() because it might return a reference 1453 * to a shared cluster. Both this function and ip_output() 1454 * assume exclusive access to the IP header in `m', so any 1455 * data in a cluster may change before we reach icmp_error(). 1456 */ 1457 MGETHDR(mcopy, M_DONTWAIT, m->m_type); 1458 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1459 /* 1460 * It's probably ok if the pkthdr dup fails (because 1461 * the deep copy of the tag chain failed), but for now 1462 * be conservative and just discard the copy since 1463 * code below may some day want the tags. 1464 */ 1465 m_free(mcopy); 1466 mcopy = NULL; 1467 } 1468 if (mcopy != NULL) { 1469 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy)); 1470 mcopy->m_pkthdr.len = mcopy->m_len; 1471 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1472 } 1473 1474 #ifdef IPSTEALTH 1475 if (!V_ipstealth) { 1476 #endif 1477 ip->ip_ttl -= IPTTLDEC; 1478 #ifdef IPSTEALTH 1479 } 1480 #endif 1481 1482 /* 1483 * If forwarding packet using same interface that it came in on, 1484 * perhaps should send a redirect to sender to shortcut a hop. 1485 * Only send redirect if source is sending directly to us, 1486 * and if packet was not source routed (or has any options). 1487 * Also, don't send redirect if forwarding using a default route 1488 * or a route modified by a redirect. 1489 */ 1490 dest.s_addr = 0; 1491 if (!srcrt && V_ipsendredirects && 1492 ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) { 1493 struct sockaddr_in *sin; 1494 struct rtentry *rt; 1495 1496 bzero(&ro, sizeof(ro)); 1497 sin = (struct sockaddr_in *)&ro.ro_dst; 1498 sin->sin_family = AF_INET; 1499 sin->sin_len = sizeof(*sin); 1500 sin->sin_addr = ip->ip_dst; 1501 in_rtalloc_ign(&ro, 0, M_GETFIB(m)); 1502 1503 rt = ro.ro_rt; 1504 1505 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1506 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1507 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1508 u_long src = ntohl(ip->ip_src.s_addr); 1509 1510 if (RTA(rt) && 1511 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1512 if (rt->rt_flags & RTF_GATEWAY) 1513 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1514 else 1515 dest.s_addr = ip->ip_dst.s_addr; 1516 /* Router requirements says to only send host redirects */ 1517 type = ICMP_REDIRECT; 1518 code = ICMP_REDIRECT_HOST; 1519 } 1520 } 1521 if (rt) 1522 RTFREE(rt); 1523 } 1524 1525 /* 1526 * Try to cache the route MTU from ip_output so we can consider it for 1527 * the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191. 1528 */ 1529 bzero(&ro, sizeof(ro)); 1530 1531 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL); 1532 1533 if (error == EMSGSIZE && ro.ro_rt) 1534 mtu = ro.ro_rt->rt_rmx.rmx_mtu; 1535 if (ro.ro_rt) 1536 RTFREE(ro.ro_rt); 1537 1538 if (error) 1539 IPSTAT_INC(ips_cantforward); 1540 else { 1541 IPSTAT_INC(ips_forward); 1542 if (type) 1543 IPSTAT_INC(ips_redirectsent); 1544 else { 1545 if (mcopy) 1546 m_freem(mcopy); 1547 if (ia != NULL) 1548 ifa_free(&ia->ia_ifa); 1549 return; 1550 } 1551 } 1552 if (mcopy == NULL) { 1553 if (ia != NULL) 1554 ifa_free(&ia->ia_ifa); 1555 return; 1556 } 1557 1558 switch (error) { 1559 1560 case 0: /* forwarded, but need redirect */ 1561 /* type, code set above */ 1562 break; 1563 1564 case ENETUNREACH: 1565 case EHOSTUNREACH: 1566 case ENETDOWN: 1567 case EHOSTDOWN: 1568 default: 1569 type = ICMP_UNREACH; 1570 code = ICMP_UNREACH_HOST; 1571 break; 1572 1573 case EMSGSIZE: 1574 type = ICMP_UNREACH; 1575 code = ICMP_UNREACH_NEEDFRAG; 1576 1577 #ifdef IPSEC 1578 /* 1579 * If IPsec is configured for this path, 1580 * override any possibly mtu value set by ip_output. 1581 */ 1582 mtu = ip_ipsec_mtu(mcopy, mtu); 1583 #endif /* IPSEC */ 1584 /* 1585 * If the MTU was set before make sure we are below the 1586 * interface MTU. 1587 * If the MTU wasn't set before use the interface mtu or 1588 * fall back to the next smaller mtu step compared to the 1589 * current packet size. 1590 */ 1591 if (mtu != 0) { 1592 if (ia != NULL) 1593 mtu = min(mtu, ia->ia_ifp->if_mtu); 1594 } else { 1595 if (ia != NULL) 1596 mtu = ia->ia_ifp->if_mtu; 1597 else 1598 mtu = ip_next_mtu(ip->ip_len, 0); 1599 } 1600 IPSTAT_INC(ips_cantfrag); 1601 break; 1602 1603 case ENOBUFS: 1604 /* 1605 * A router should not generate ICMP_SOURCEQUENCH as 1606 * required in RFC1812 Requirements for IP Version 4 Routers. 1607 * Source quench could be a big problem under DoS attacks, 1608 * or if the underlying interface is rate-limited. 1609 * Those who need source quench packets may re-enable them 1610 * via the net.inet.ip.sendsourcequench sysctl. 1611 */ 1612 if (V_ip_sendsourcequench == 0) { 1613 m_freem(mcopy); 1614 if (ia != NULL) 1615 ifa_free(&ia->ia_ifa); 1616 return; 1617 } else { 1618 type = ICMP_SOURCEQUENCH; 1619 code = 0; 1620 } 1621 break; 1622 1623 case EACCES: /* ipfw denied packet */ 1624 m_freem(mcopy); 1625 if (ia != NULL) 1626 ifa_free(&ia->ia_ifa); 1627 return; 1628 } 1629 if (ia != NULL) 1630 ifa_free(&ia->ia_ifa); 1631 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1632 } 1633 1634 void 1635 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1636 struct mbuf *m) 1637 { 1638 1639 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1640 struct bintime bt; 1641 1642 bintime(&bt); 1643 if (inp->inp_socket->so_options & SO_BINTIME) { 1644 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 1645 SCM_BINTIME, SOL_SOCKET); 1646 if (*mp) 1647 mp = &(*mp)->m_next; 1648 } 1649 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1650 struct timeval tv; 1651 1652 bintime2timeval(&bt, &tv); 1653 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1654 SCM_TIMESTAMP, SOL_SOCKET); 1655 if (*mp) 1656 mp = &(*mp)->m_next; 1657 } 1658 } 1659 if (inp->inp_flags & INP_RECVDSTADDR) { 1660 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1661 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1662 if (*mp) 1663 mp = &(*mp)->m_next; 1664 } 1665 if (inp->inp_flags & INP_RECVTTL) { 1666 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1667 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1668 if (*mp) 1669 mp = &(*mp)->m_next; 1670 } 1671 #ifdef notyet 1672 /* XXX 1673 * Moving these out of udp_input() made them even more broken 1674 * than they already were. 1675 */ 1676 /* options were tossed already */ 1677 if (inp->inp_flags & INP_RECVOPTS) { 1678 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1679 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1680 if (*mp) 1681 mp = &(*mp)->m_next; 1682 } 1683 /* ip_srcroute doesn't do what we want here, need to fix */ 1684 if (inp->inp_flags & INP_RECVRETOPTS) { 1685 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1686 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1687 if (*mp) 1688 mp = &(*mp)->m_next; 1689 } 1690 #endif 1691 if (inp->inp_flags & INP_RECVIF) { 1692 struct ifnet *ifp; 1693 struct sdlbuf { 1694 struct sockaddr_dl sdl; 1695 u_char pad[32]; 1696 } sdlbuf; 1697 struct sockaddr_dl *sdp; 1698 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1699 1700 if (((ifp = m->m_pkthdr.rcvif)) 1701 && ( ifp->if_index && (ifp->if_index <= V_if_index))) { 1702 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1703 /* 1704 * Change our mind and don't try copy. 1705 */ 1706 if ((sdp->sdl_family != AF_LINK) 1707 || (sdp->sdl_len > sizeof(sdlbuf))) { 1708 goto makedummy; 1709 } 1710 bcopy(sdp, sdl2, sdp->sdl_len); 1711 } else { 1712 makedummy: 1713 sdl2->sdl_len 1714 = offsetof(struct sockaddr_dl, sdl_data[0]); 1715 sdl2->sdl_family = AF_LINK; 1716 sdl2->sdl_index = 0; 1717 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1718 } 1719 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1720 IP_RECVIF, IPPROTO_IP); 1721 if (*mp) 1722 mp = &(*mp)->m_next; 1723 } 1724 } 1725 1726 /* 1727 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the 1728 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on 1729 * locking. This code remains in ip_input.c as ip_mroute.c is optionally 1730 * compiled. 1731 */ 1732 static VNET_DEFINE(int, ip_rsvp_on); 1733 VNET_DEFINE(struct socket *, ip_rsvpd); 1734 1735 #define V_ip_rsvp_on VNET(ip_rsvp_on) 1736 1737 int 1738 ip_rsvp_init(struct socket *so) 1739 { 1740 1741 if (so->so_type != SOCK_RAW || 1742 so->so_proto->pr_protocol != IPPROTO_RSVP) 1743 return EOPNOTSUPP; 1744 1745 if (V_ip_rsvpd != NULL) 1746 return EADDRINUSE; 1747 1748 V_ip_rsvpd = so; 1749 /* 1750 * This may seem silly, but we need to be sure we don't over-increment 1751 * the RSVP counter, in case something slips up. 1752 */ 1753 if (!V_ip_rsvp_on) { 1754 V_ip_rsvp_on = 1; 1755 V_rsvp_on++; 1756 } 1757 1758 return 0; 1759 } 1760 1761 int 1762 ip_rsvp_done(void) 1763 { 1764 1765 V_ip_rsvpd = NULL; 1766 /* 1767 * This may seem silly, but we need to be sure we don't over-decrement 1768 * the RSVP counter, in case something slips up. 1769 */ 1770 if (V_ip_rsvp_on) { 1771 V_ip_rsvp_on = 0; 1772 V_rsvp_on--; 1773 } 1774 return 0; 1775 } 1776 1777 void 1778 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1779 { 1780 1781 if (rsvp_input_p) { /* call the real one if loaded */ 1782 rsvp_input_p(m, off); 1783 return; 1784 } 1785 1786 /* Can still get packets with rsvp_on = 0 if there is a local member 1787 * of the group to which the RSVP packet is addressed. But in this 1788 * case we want to throw the packet away. 1789 */ 1790 1791 if (!V_rsvp_on) { 1792 m_freem(m); 1793 return; 1794 } 1795 1796 if (V_ip_rsvpd != NULL) { 1797 rip_input(m, off); 1798 return; 1799 } 1800 /* Drop the packet */ 1801 m_freem(m); 1802 }
Cache object: cd8c6ce059f56a6aa3caccef8d515c6e
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