1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_bootp.h" 36 #include "opt_ipfw.h" 37 #include "opt_ipstealth.h" 38 #include "opt_ipsec.h" 39 #include "opt_route.h" 40 #include "opt_carp.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/callout.h> 45 #include <sys/mbuf.h> 46 #include <sys/malloc.h> 47 #include <sys/domain.h> 48 #include <sys/protosw.h> 49 #include <sys/socket.h> 50 #include <sys/time.h> 51 #include <sys/kernel.h> 52 #include <sys/lock.h> 53 #include <sys/rwlock.h> 54 #include <sys/syslog.h> 55 #include <sys/sysctl.h> 56 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 static VNET_DEFINE(int, ipsendredirects) = 1; /* XXX */ 93 static VNET_DEFINE(int, ip_checkinterface); 94 static VNET_DEFINE(int, ip_keepfaith); 95 static VNET_DEFINE(int, ip_sendsourcequench); 96 97 #define V_ipsendredirects VNET(ipsendredirects) 98 #define V_ip_checkinterface VNET(ip_checkinterface) 99 #define V_ip_keepfaith VNET(ip_keepfaith) 100 #define V_ip_sendsourcequench VNET(ip_sendsourcequench) 101 102 VNET_DEFINE(int, ip_defttl) = IPDEFTTL; 103 VNET_DEFINE(int, ip_do_randomid); 104 VNET_DEFINE(int, ipforwarding); 105 106 VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */ 107 VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */ 108 VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */ 109 VNET_DEFINE(struct ipstat, ipstat); 110 111 static VNET_DEFINE(int, ip_rsvp_on); 112 VNET_DEFINE(struct socket *, ip_rsvpd); 113 VNET_DEFINE(int, rsvp_on); 114 115 #define V_ip_rsvp_on VNET(ip_rsvp_on) 116 117 static VNET_DEFINE(TAILQ_HEAD(ipqhead, ipq), ipq[IPREASS_NHASH]); 118 static VNET_DEFINE(int, maxnipq); /* Administrative limit on # reass queues. */ 119 static VNET_DEFINE(int, maxfragsperpacket); 120 static VNET_DEFINE(int, nipq); /* Total # of reass queues */ 121 122 #define V_ipq VNET(ipq) 123 #define V_maxnipq VNET(maxnipq) 124 #define V_maxfragsperpacket VNET(maxfragsperpacket) 125 #define V_nipq VNET(nipq) 126 127 VNET_DEFINE(int, ipstealth); 128 129 struct rwlock in_ifaddr_lock; 130 RW_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock"); 131 132 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 133 &VNET_NAME(ipforwarding), 0, 134 "Enable IP forwarding between interfaces"); 135 136 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 137 &VNET_NAME(ipsendredirects), 0, 138 "Enable sending IP redirects"); 139 140 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 141 &VNET_NAME(ip_defttl), 0, 142 "Maximum TTL on IP packets"); 143 144 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 145 &VNET_NAME(ip_keepfaith), 0, 146 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 147 148 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 149 &VNET_NAME(ip_sendsourcequench), 0, 150 "Enable the transmission of source quench packets"); 151 152 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 153 &VNET_NAME(ip_do_randomid), 0, 154 "Assign random ip_id values"); 155 156 /* 157 * XXX - Setting ip_checkinterface mostly implements the receive side of 158 * the Strong ES model described in RFC 1122, but since the routing table 159 * and transmit implementation do not implement the Strong ES model, 160 * setting this to 1 results in an odd hybrid. 161 * 162 * XXX - ip_checkinterface currently must be disabled if you use ipnat 163 * to translate the destination address to another local interface. 164 * 165 * XXX - ip_checkinterface must be disabled if you add IP aliases 166 * to the loopback interface instead of the interface where the 167 * packets for those addresses are received. 168 */ 169 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 170 &VNET_NAME(ip_checkinterface), 0, 171 "Verify packet arrives on correct interface"); 172 173 VNET_DEFINE(struct pfil_head, inet_pfil_hook); /* Packet filter hooks */ 174 175 static struct netisr_handler ip_nh = { 176 .nh_name = "ip", 177 .nh_handler = ip_input, 178 .nh_proto = NETISR_IP, 179 .nh_policy = NETISR_POLICY_FLOW, 180 }; 181 182 extern struct domain inetdomain; 183 extern struct protosw inetsw[]; 184 u_char ip_protox[IPPROTO_MAX]; 185 186 SYSCTL_VNET_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 187 &VNET_NAME(ipstat), ipstat, 188 "IP statistics (struct ipstat, netinet/ip_var.h)"); 189 190 static VNET_DEFINE(uma_zone_t, ipq_zone); 191 #define V_ipq_zone VNET(ipq_zone) 192 193 static struct mtx ipqlock; 194 195 #define IPQ_LOCK() mtx_lock(&ipqlock) 196 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 197 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 198 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 199 200 static void maxnipq_update(void); 201 static void ipq_zone_change(void *); 202 static void ip_drain_locked(void); 203 204 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, 205 &VNET_NAME(nipq), 0, 206 "Current number of IPv4 fragment reassembly queue entries"); 207 208 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 209 &VNET_NAME(maxfragsperpacket), 0, 210 "Maximum number of IPv4 fragments allowed per packet"); 211 212 struct callout ipport_tick_callout; 213 214 #ifdef IPCTL_DEFMTU 215 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 216 &ip_mtu, 0, "Default MTU"); 217 #endif 218 219 #ifdef IPSTEALTH 220 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 221 &VNET_NAME(ipstealth), 0, 222 "IP stealth mode, no TTL decrementation on forwarding"); 223 #endif 224 225 #ifdef FLOWTABLE 226 static VNET_DEFINE(int, ip_output_flowtable_size) = 2048; 227 VNET_DEFINE(struct flowtable *, ip_ft); 228 #define V_ip_output_flowtable_size VNET(ip_output_flowtable_size) 229 230 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, output_flowtable_size, CTLFLAG_RDTUN, 231 &VNET_NAME(ip_output_flowtable_size), 2048, 232 "number of entries in the per-cpu output flow caches"); 233 #endif 234 235 VNET_DEFINE(int, fw_one_pass) = 1; 236 237 static void ip_freef(struct ipqhead *, struct ipq *); 238 239 /* 240 * Kernel module interface for updating ipstat. The argument is an index 241 * into ipstat treated as an array of u_long. While this encodes the general 242 * layout of ipstat into the caller, it doesn't encode its location, so that 243 * future changes to add, for example, per-CPU stats support won't cause 244 * binary compatibility problems for kernel modules. 245 */ 246 void 247 kmod_ipstat_inc(int statnum) 248 { 249 250 (*((u_long *)&V_ipstat + statnum))++; 251 } 252 253 void 254 kmod_ipstat_dec(int statnum) 255 { 256 257 (*((u_long *)&V_ipstat + statnum))--; 258 } 259 260 static int 261 sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS) 262 { 263 int error, qlimit; 264 265 netisr_getqlimit(&ip_nh, &qlimit); 266 error = sysctl_handle_int(oidp, &qlimit, 0, req); 267 if (error || !req->newptr) 268 return (error); 269 if (qlimit < 1) 270 return (EINVAL); 271 return (netisr_setqlimit(&ip_nh, qlimit)); 272 } 273 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, 274 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I", 275 "Maximum size of the IP input queue"); 276 277 static int 278 sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS) 279 { 280 u_int64_t qdrops_long; 281 int error, qdrops; 282 283 netisr_getqdrops(&ip_nh, &qdrops_long); 284 qdrops = qdrops_long; 285 error = sysctl_handle_int(oidp, &qdrops, 0, req); 286 if (error || !req->newptr) 287 return (error); 288 if (qdrops != 0) 289 return (EINVAL); 290 netisr_clearqdrops(&ip_nh); 291 return (0); 292 } 293 294 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, 295 CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I", 296 "Number of packets dropped from the IP input queue"); 297 298 /* 299 * IP initialization: fill in IP protocol switch table. 300 * All protocols not implemented in kernel go to raw IP protocol handler. 301 */ 302 void 303 ip_init(void) 304 { 305 struct protosw *pr; 306 int i; 307 308 V_ip_id = time_second & 0xffff; 309 310 TAILQ_INIT(&V_in_ifaddrhead); 311 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask); 312 313 /* Initialize IP reassembly queue. */ 314 for (i = 0; i < IPREASS_NHASH; i++) 315 TAILQ_INIT(&V_ipq[i]); 316 V_maxnipq = nmbclusters / 32; 317 V_maxfragsperpacket = 16; 318 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 319 NULL, UMA_ALIGN_PTR, 0); 320 maxnipq_update(); 321 322 /* Initialize packet filter hooks. */ 323 V_inet_pfil_hook.ph_type = PFIL_TYPE_AF; 324 V_inet_pfil_hook.ph_af = AF_INET; 325 if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0) 326 printf("%s: WARNING: unable to register pfil hook, " 327 "error %d\n", __func__, i); 328 329 #ifdef FLOWTABLE 330 if (TUNABLE_INT_FETCH("net.inet.ip.output_flowtable_size", 331 &V_ip_output_flowtable_size)) { 332 if (V_ip_output_flowtable_size < 256) 333 V_ip_output_flowtable_size = 256; 334 if (!powerof2(V_ip_output_flowtable_size)) { 335 printf("flowtable must be power of 2 size\n"); 336 V_ip_output_flowtable_size = 2048; 337 } 338 } else { 339 /* 340 * round up to the next power of 2 341 */ 342 V_ip_output_flowtable_size = 1 << fls((1024 + maxusers * 64)-1); 343 } 344 V_ip_ft = flowtable_alloc("ipv4", V_ip_output_flowtable_size, FL_PCPU); 345 #endif 346 347 /* Skip initialization of globals for non-default instances. */ 348 if (!IS_DEFAULT_VNET(curvnet)) 349 return; 350 351 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 352 if (pr == NULL) 353 panic("ip_init: PF_INET not found"); 354 355 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 356 for (i = 0; i < IPPROTO_MAX; i++) 357 ip_protox[i] = pr - inetsw; 358 /* 359 * Cycle through IP protocols and put them into the appropriate place 360 * in ip_protox[]. 361 */ 362 for (pr = inetdomain.dom_protosw; 363 pr < inetdomain.dom_protoswNPROTOSW; pr++) 364 if (pr->pr_domain->dom_family == PF_INET && 365 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 366 /* Be careful to only index valid IP protocols. */ 367 if (pr->pr_protocol < IPPROTO_MAX) 368 ip_protox[pr->pr_protocol] = pr - inetsw; 369 } 370 371 /* Start ipport_tick. */ 372 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE); 373 callout_reset(&ipport_tick_callout, 1, ipport_tick, NULL); 374 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL, 375 SHUTDOWN_PRI_DEFAULT); 376 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, 377 NULL, EVENTHANDLER_PRI_ANY); 378 379 /* Initialize various other remaining things. */ 380 IPQ_LOCK_INIT(); 381 netisr_register(&ip_nh); 382 } 383 384 #ifdef VIMAGE 385 void 386 ip_destroy(void) 387 { 388 389 /* Cleanup in_ifaddr hash table; should be empty. */ 390 hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask); 391 392 IPQ_LOCK(); 393 ip_drain_locked(); 394 IPQ_UNLOCK(); 395 396 uma_zdestroy(V_ipq_zone); 397 } 398 #endif 399 400 void 401 ip_fini(void *xtp) 402 { 403 404 callout_stop(&ipport_tick_callout); 405 } 406 407 /* 408 * Ip input routine. Checksum and byte swap header. If fragmented 409 * try to reassemble. Process options. Pass to next level. 410 */ 411 void 412 ip_input(struct mbuf *m) 413 { 414 struct ip *ip = NULL; 415 struct in_ifaddr *ia = NULL; 416 struct ifaddr *ifa; 417 struct ifnet *ifp; 418 int checkif, hlen = 0; 419 u_short sum; 420 int dchg = 0; /* dest changed after fw */ 421 struct in_addr odst; /* original dst address */ 422 423 M_ASSERTPKTHDR(m); 424 425 if (m->m_flags & M_FASTFWD_OURS) { 426 /* 427 * Firewall or NAT changed destination to local. 428 * We expect ip_len and ip_off to be in host byte order. 429 */ 430 m->m_flags &= ~M_FASTFWD_OURS; 431 /* Set up some basics that will be used later. */ 432 ip = mtod(m, struct ip *); 433 hlen = ip->ip_hl << 2; 434 goto ours; 435 } 436 437 IPSTAT_INC(ips_total); 438 439 if (m->m_pkthdr.len < sizeof(struct ip)) 440 goto tooshort; 441 442 if (m->m_len < sizeof (struct ip) && 443 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 444 IPSTAT_INC(ips_toosmall); 445 return; 446 } 447 ip = mtod(m, struct ip *); 448 449 if (ip->ip_v != IPVERSION) { 450 IPSTAT_INC(ips_badvers); 451 goto bad; 452 } 453 454 hlen = ip->ip_hl << 2; 455 if (hlen < sizeof(struct ip)) { /* minimum header length */ 456 IPSTAT_INC(ips_badhlen); 457 goto bad; 458 } 459 if (hlen > m->m_len) { 460 if ((m = m_pullup(m, hlen)) == NULL) { 461 IPSTAT_INC(ips_badhlen); 462 return; 463 } 464 ip = mtod(m, struct ip *); 465 } 466 467 /* 127/8 must not appear on wire - RFC1122 */ 468 ifp = m->m_pkthdr.rcvif; 469 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 470 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 471 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 472 IPSTAT_INC(ips_badaddr); 473 goto bad; 474 } 475 } 476 477 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 478 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 479 } else { 480 if (hlen == sizeof(struct ip)) { 481 sum = in_cksum_hdr(ip); 482 } else { 483 sum = in_cksum(m, hlen); 484 } 485 } 486 if (sum) { 487 IPSTAT_INC(ips_badsum); 488 goto bad; 489 } 490 491 #ifdef ALTQ 492 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 493 /* packet is dropped by traffic conditioner */ 494 return; 495 #endif 496 497 /* 498 * Convert fields to host representation. 499 */ 500 ip->ip_len = ntohs(ip->ip_len); 501 if (ip->ip_len < hlen) { 502 IPSTAT_INC(ips_badlen); 503 goto bad; 504 } 505 ip->ip_off = ntohs(ip->ip_off); 506 507 /* 508 * Check that the amount of data in the buffers 509 * is as at least much as the IP header would have us expect. 510 * Trim mbufs if longer than we expect. 511 * Drop packet if shorter than we expect. 512 */ 513 if (m->m_pkthdr.len < ip->ip_len) { 514 tooshort: 515 IPSTAT_INC(ips_tooshort); 516 goto bad; 517 } 518 if (m->m_pkthdr.len > ip->ip_len) { 519 if (m->m_len == m->m_pkthdr.len) { 520 m->m_len = ip->ip_len; 521 m->m_pkthdr.len = ip->ip_len; 522 } else 523 m_adj(m, ip->ip_len - m->m_pkthdr.len); 524 } 525 #ifdef IPSEC 526 /* 527 * Bypass packet filtering for packets from a tunnel (gif). 528 */ 529 if (ip_ipsec_filtertunnel(m)) 530 goto passin; 531 #endif /* IPSEC */ 532 533 /* 534 * Run through list of hooks for input packets. 535 * 536 * NB: Beware of the destination address changing (e.g. 537 * by NAT rewriting). When this happens, tell 538 * ip_forward to do the right thing. 539 */ 540 541 /* Jump over all PFIL processing if hooks are not active. */ 542 if (!PFIL_HOOKED(&V_inet_pfil_hook)) 543 goto passin; 544 545 odst = ip->ip_dst; 546 if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0) 547 return; 548 if (m == NULL) /* consumed by filter */ 549 return; 550 551 ip = mtod(m, struct ip *); 552 dchg = (odst.s_addr != ip->ip_dst.s_addr); 553 ifp = m->m_pkthdr.rcvif; 554 555 #ifdef IPFIREWALL_FORWARD 556 if (m->m_flags & M_FASTFWD_OURS) { 557 m->m_flags &= ~M_FASTFWD_OURS; 558 goto ours; 559 } 560 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 561 /* 562 * Directly ship the packet on. This allows forwarding 563 * packets originally destined to us to some other directly 564 * connected host. 565 */ 566 ip_forward(m, dchg); 567 return; 568 } 569 #endif /* IPFIREWALL_FORWARD */ 570 571 passin: 572 /* 573 * Process options and, if not destined for us, 574 * ship it on. ip_dooptions returns 1 when an 575 * error was detected (causing an icmp message 576 * to be sent and the original packet to be freed). 577 */ 578 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 579 return; 580 581 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 582 * matter if it is destined to another node, or whether it is 583 * a multicast one, RSVP wants it! and prevents it from being forwarded 584 * anywhere else. Also checks if the rsvp daemon is running before 585 * grabbing the packet. 586 */ 587 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP) 588 goto ours; 589 590 /* 591 * Check our list of addresses, to see if the packet is for us. 592 * If we don't have any addresses, assume any unicast packet 593 * we receive might be for us (and let the upper layers deal 594 * with it). 595 */ 596 if (TAILQ_EMPTY(&V_in_ifaddrhead) && 597 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 598 goto ours; 599 600 /* 601 * Enable a consistency check between the destination address 602 * and the arrival interface for a unicast packet (the RFC 1122 603 * strong ES model) if IP forwarding is disabled and the packet 604 * is not locally generated and the packet is not subject to 605 * 'ipfw fwd'. 606 * 607 * XXX - Checking also should be disabled if the destination 608 * address is ipnat'ed to a different interface. 609 * 610 * XXX - Checking is incompatible with IP aliases added 611 * to the loopback interface instead of the interface where 612 * the packets are received. 613 * 614 * XXX - This is the case for carp vhost IPs as well so we 615 * insert a workaround. If the packet got here, we already 616 * checked with carp_iamatch() and carp_forus(). 617 */ 618 checkif = V_ip_checkinterface && (V_ipforwarding == 0) && 619 ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) && 620 #ifdef DEV_CARP 621 !ifp->if_carp && 622 #endif 623 (dchg == 0); 624 625 /* 626 * Check for exact addresses in the hash bucket. 627 */ 628 /* IN_IFADDR_RLOCK(); */ 629 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 630 /* 631 * If the address matches, verify that the packet 632 * arrived via the correct interface if checking is 633 * enabled. 634 */ 635 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 636 (!checkif || ia->ia_ifp == ifp)) { 637 ifa_ref(&ia->ia_ifa); 638 /* IN_IFADDR_RUNLOCK(); */ 639 goto ours; 640 } 641 } 642 /* IN_IFADDR_RUNLOCK(); */ 643 644 /* 645 * Check for broadcast addresses. 646 * 647 * Only accept broadcast packets that arrive via the matching 648 * interface. Reception of forwarded directed broadcasts would 649 * be handled via ip_forward() and ether_output() with the loopback 650 * into the stack for SIMPLEX interfaces handled by ether_output(). 651 */ 652 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) { 653 IF_ADDR_LOCK(ifp); 654 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 655 if (ifa->ifa_addr->sa_family != AF_INET) 656 continue; 657 ia = ifatoia(ifa); 658 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 659 ip->ip_dst.s_addr) { 660 ifa_ref(ifa); 661 IF_ADDR_UNLOCK(ifp); 662 goto ours; 663 } 664 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) { 665 ifa_ref(ifa); 666 IF_ADDR_UNLOCK(ifp); 667 goto ours; 668 } 669 #ifdef BOOTP_COMPAT 670 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) { 671 ifa_ref(ifa); 672 IF_ADDR_UNLOCK(ifp); 673 goto ours; 674 } 675 #endif 676 } 677 IF_ADDR_UNLOCK(ifp); 678 ia = NULL; 679 } 680 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */ 681 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) { 682 IPSTAT_INC(ips_cantforward); 683 m_freem(m); 684 return; 685 } 686 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 687 if (V_ip_mrouter) { 688 /* 689 * If we are acting as a multicast router, all 690 * incoming multicast packets are passed to the 691 * kernel-level multicast forwarding function. 692 * The packet is returned (relatively) intact; if 693 * ip_mforward() returns a non-zero value, the packet 694 * must be discarded, else it may be accepted below. 695 */ 696 if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) { 697 IPSTAT_INC(ips_cantforward); 698 m_freem(m); 699 return; 700 } 701 702 /* 703 * The process-level routing daemon needs to receive 704 * all multicast IGMP packets, whether or not this 705 * host belongs to their destination groups. 706 */ 707 if (ip->ip_p == IPPROTO_IGMP) 708 goto ours; 709 IPSTAT_INC(ips_forward); 710 } 711 /* 712 * Assume the packet is for us, to avoid prematurely taking 713 * a lock on the in_multi hash. Protocols must perform 714 * their own filtering and update statistics accordingly. 715 */ 716 goto ours; 717 } 718 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 719 goto ours; 720 if (ip->ip_dst.s_addr == INADDR_ANY) 721 goto ours; 722 723 /* 724 * FAITH(Firewall Aided Internet Translator) 725 */ 726 if (ifp && ifp->if_type == IFT_FAITH) { 727 if (V_ip_keepfaith) { 728 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 729 goto ours; 730 } 731 m_freem(m); 732 return; 733 } 734 735 /* 736 * Not for us; forward if possible and desirable. 737 */ 738 if (V_ipforwarding == 0) { 739 IPSTAT_INC(ips_cantforward); 740 m_freem(m); 741 } else { 742 #ifdef IPSEC 743 if (ip_ipsec_fwd(m)) 744 goto bad; 745 #endif /* IPSEC */ 746 ip_forward(m, dchg); 747 } 748 return; 749 750 ours: 751 #ifdef IPSTEALTH 752 /* 753 * IPSTEALTH: Process non-routing options only 754 * if the packet is destined for us. 755 */ 756 if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1)) { 757 if (ia != NULL) 758 ifa_free(&ia->ia_ifa); 759 return; 760 } 761 #endif /* IPSTEALTH */ 762 763 /* Count the packet in the ip address stats */ 764 if (ia != NULL) { 765 ia->ia_ifa.if_ipackets++; 766 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 767 ifa_free(&ia->ia_ifa); 768 } 769 770 /* 771 * Attempt reassembly; if it succeeds, proceed. 772 * ip_reass() will return a different mbuf. 773 */ 774 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 775 m = ip_reass(m); 776 if (m == NULL) 777 return; 778 ip = mtod(m, struct ip *); 779 /* Get the header length of the reassembled packet */ 780 hlen = ip->ip_hl << 2; 781 } 782 783 /* 784 * Further protocols expect the packet length to be w/o the 785 * IP header. 786 */ 787 ip->ip_len -= hlen; 788 789 #ifdef IPSEC 790 /* 791 * enforce IPsec policy checking if we are seeing last header. 792 * note that we do not visit this with protocols with pcb layer 793 * code - like udp/tcp/raw ip. 794 */ 795 if (ip_ipsec_input(m)) 796 goto bad; 797 #endif /* IPSEC */ 798 799 /* 800 * Switch out to protocol's input routine. 801 */ 802 IPSTAT_INC(ips_delivered); 803 804 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 805 return; 806 bad: 807 m_freem(m); 808 } 809 810 /* 811 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 812 * max has slightly different semantics than the sysctl, for historical 813 * reasons. 814 */ 815 static void 816 maxnipq_update(void) 817 { 818 819 /* 820 * -1 for unlimited allocation. 821 */ 822 if (V_maxnipq < 0) 823 uma_zone_set_max(V_ipq_zone, 0); 824 /* 825 * Positive number for specific bound. 826 */ 827 if (V_maxnipq > 0) 828 uma_zone_set_max(V_ipq_zone, V_maxnipq); 829 /* 830 * Zero specifies no further fragment queue allocation -- set the 831 * bound very low, but rely on implementation elsewhere to actually 832 * prevent allocation and reclaim current queues. 833 */ 834 if (V_maxnipq == 0) 835 uma_zone_set_max(V_ipq_zone, 1); 836 } 837 838 static void 839 ipq_zone_change(void *tag) 840 { 841 842 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) { 843 V_maxnipq = nmbclusters / 32; 844 maxnipq_update(); 845 } 846 } 847 848 static int 849 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 850 { 851 int error, i; 852 853 i = V_maxnipq; 854 error = sysctl_handle_int(oidp, &i, 0, req); 855 if (error || !req->newptr) 856 return (error); 857 858 /* 859 * XXXRW: Might be a good idea to sanity check the argument and place 860 * an extreme upper bound. 861 */ 862 if (i < -1) 863 return (EINVAL); 864 V_maxnipq = i; 865 maxnipq_update(); 866 return (0); 867 } 868 869 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 870 NULL, 0, sysctl_maxnipq, "I", 871 "Maximum number of IPv4 fragment reassembly queue entries"); 872 873 /* 874 * Take incoming datagram fragment and try to reassemble it into 875 * whole datagram. If the argument is the first fragment or one 876 * in between the function will return NULL and store the mbuf 877 * in the fragment chain. If the argument is the last fragment 878 * the packet will be reassembled and the pointer to the new 879 * mbuf returned for further processing. Only m_tags attached 880 * to the first packet/fragment are preserved. 881 * The IP header is *NOT* adjusted out of iplen. 882 */ 883 struct mbuf * 884 ip_reass(struct mbuf *m) 885 { 886 struct ip *ip; 887 struct mbuf *p, *q, *nq, *t; 888 struct ipq *fp = NULL; 889 struct ipqhead *head; 890 int i, hlen, next; 891 u_int8_t ecn, ecn0; 892 u_short hash; 893 894 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 895 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) { 896 IPSTAT_INC(ips_fragments); 897 IPSTAT_INC(ips_fragdropped); 898 m_freem(m); 899 return (NULL); 900 } 901 902 ip = mtod(m, struct ip *); 903 hlen = ip->ip_hl << 2; 904 905 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 906 head = &V_ipq[hash]; 907 IPQ_LOCK(); 908 909 /* 910 * Look for queue of fragments 911 * of this datagram. 912 */ 913 TAILQ_FOREACH(fp, head, ipq_list) 914 if (ip->ip_id == fp->ipq_id && 915 ip->ip_src.s_addr == fp->ipq_src.s_addr && 916 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 917 #ifdef MAC 918 mac_ipq_match(m, fp) && 919 #endif 920 ip->ip_p == fp->ipq_p) 921 goto found; 922 923 fp = NULL; 924 925 /* 926 * Attempt to trim the number of allocated fragment queues if it 927 * exceeds the administrative limit. 928 */ 929 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) { 930 /* 931 * drop something from the tail of the current queue 932 * before proceeding further 933 */ 934 struct ipq *q = TAILQ_LAST(head, ipqhead); 935 if (q == NULL) { /* gak */ 936 for (i = 0; i < IPREASS_NHASH; i++) { 937 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead); 938 if (r) { 939 IPSTAT_ADD(ips_fragtimeout, 940 r->ipq_nfrags); 941 ip_freef(&V_ipq[i], r); 942 break; 943 } 944 } 945 } else { 946 IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags); 947 ip_freef(head, q); 948 } 949 } 950 951 found: 952 /* 953 * Adjust ip_len to not reflect header, 954 * convert offset of this to bytes. 955 */ 956 ip->ip_len -= hlen; 957 if (ip->ip_off & IP_MF) { 958 /* 959 * Make sure that fragments have a data length 960 * that's a non-zero multiple of 8 bytes. 961 */ 962 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 963 IPSTAT_INC(ips_toosmall); /* XXX */ 964 goto dropfrag; 965 } 966 m->m_flags |= M_FRAG; 967 } else 968 m->m_flags &= ~M_FRAG; 969 ip->ip_off <<= 3; 970 971 972 /* 973 * Attempt reassembly; if it succeeds, proceed. 974 * ip_reass() will return a different mbuf. 975 */ 976 IPSTAT_INC(ips_fragments); 977 m->m_pkthdr.header = ip; 978 979 /* Previous ip_reass() started here. */ 980 /* 981 * Presence of header sizes in mbufs 982 * would confuse code below. 983 */ 984 m->m_data += hlen; 985 m->m_len -= hlen; 986 987 /* 988 * If first fragment to arrive, create a reassembly queue. 989 */ 990 if (fp == NULL) { 991 fp = uma_zalloc(V_ipq_zone, M_NOWAIT); 992 if (fp == NULL) 993 goto dropfrag; 994 #ifdef MAC 995 if (mac_ipq_init(fp, M_NOWAIT) != 0) { 996 uma_zfree(V_ipq_zone, fp); 997 fp = NULL; 998 goto dropfrag; 999 } 1000 mac_ipq_create(m, fp); 1001 #endif 1002 TAILQ_INSERT_HEAD(head, fp, ipq_list); 1003 V_nipq++; 1004 fp->ipq_nfrags = 1; 1005 fp->ipq_ttl = IPFRAGTTL; 1006 fp->ipq_p = ip->ip_p; 1007 fp->ipq_id = ip->ip_id; 1008 fp->ipq_src = ip->ip_src; 1009 fp->ipq_dst = ip->ip_dst; 1010 fp->ipq_frags = m; 1011 m->m_nextpkt = NULL; 1012 goto done; 1013 } else { 1014 fp->ipq_nfrags++; 1015 #ifdef MAC 1016 mac_ipq_update(m, fp); 1017 #endif 1018 } 1019 1020 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1021 1022 /* 1023 * Handle ECN by comparing this segment with the first one; 1024 * if CE is set, do not lose CE. 1025 * drop if CE and not-ECT are mixed for the same packet. 1026 */ 1027 ecn = ip->ip_tos & IPTOS_ECN_MASK; 1028 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 1029 if (ecn == IPTOS_ECN_CE) { 1030 if (ecn0 == IPTOS_ECN_NOTECT) 1031 goto dropfrag; 1032 if (ecn0 != IPTOS_ECN_CE) 1033 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 1034 } 1035 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 1036 goto dropfrag; 1037 1038 /* 1039 * Find a segment which begins after this one does. 1040 */ 1041 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1042 if (GETIP(q)->ip_off > ip->ip_off) 1043 break; 1044 1045 /* 1046 * If there is a preceding segment, it may provide some of 1047 * our data already. If so, drop the data from the incoming 1048 * segment. If it provides all of our data, drop us, otherwise 1049 * stick new segment in the proper place. 1050 * 1051 * If some of the data is dropped from the the preceding 1052 * segment, then it's checksum is invalidated. 1053 */ 1054 if (p) { 1055 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1056 if (i > 0) { 1057 if (i >= ip->ip_len) 1058 goto dropfrag; 1059 m_adj(m, i); 1060 m->m_pkthdr.csum_flags = 0; 1061 ip->ip_off += i; 1062 ip->ip_len -= i; 1063 } 1064 m->m_nextpkt = p->m_nextpkt; 1065 p->m_nextpkt = m; 1066 } else { 1067 m->m_nextpkt = fp->ipq_frags; 1068 fp->ipq_frags = m; 1069 } 1070 1071 /* 1072 * While we overlap succeeding segments trim them or, 1073 * if they are completely covered, dequeue them. 1074 */ 1075 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1076 q = nq) { 1077 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1078 if (i < GETIP(q)->ip_len) { 1079 GETIP(q)->ip_len -= i; 1080 GETIP(q)->ip_off += i; 1081 m_adj(q, i); 1082 q->m_pkthdr.csum_flags = 0; 1083 break; 1084 } 1085 nq = q->m_nextpkt; 1086 m->m_nextpkt = nq; 1087 IPSTAT_INC(ips_fragdropped); 1088 fp->ipq_nfrags--; 1089 m_freem(q); 1090 } 1091 1092 /* 1093 * Check for complete reassembly and perform frag per packet 1094 * limiting. 1095 * 1096 * Frag limiting is performed here so that the nth frag has 1097 * a chance to complete the packet before we drop the packet. 1098 * As a result, n+1 frags are actually allowed per packet, but 1099 * only n will ever be stored. (n = maxfragsperpacket.) 1100 * 1101 */ 1102 next = 0; 1103 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1104 if (GETIP(q)->ip_off != next) { 1105 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1106 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1107 ip_freef(head, fp); 1108 } 1109 goto done; 1110 } 1111 next += GETIP(q)->ip_len; 1112 } 1113 /* Make sure the last packet didn't have the IP_MF flag */ 1114 if (p->m_flags & M_FRAG) { 1115 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1116 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1117 ip_freef(head, fp); 1118 } 1119 goto done; 1120 } 1121 1122 /* 1123 * Reassembly is complete. Make sure the packet is a sane size. 1124 */ 1125 q = fp->ipq_frags; 1126 ip = GETIP(q); 1127 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1128 IPSTAT_INC(ips_toolong); 1129 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1130 ip_freef(head, fp); 1131 goto done; 1132 } 1133 1134 /* 1135 * Concatenate fragments. 1136 */ 1137 m = q; 1138 t = m->m_next; 1139 m->m_next = NULL; 1140 m_cat(m, t); 1141 nq = q->m_nextpkt; 1142 q->m_nextpkt = NULL; 1143 for (q = nq; q != NULL; q = nq) { 1144 nq = q->m_nextpkt; 1145 q->m_nextpkt = NULL; 1146 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1147 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1148 m_cat(m, q); 1149 } 1150 /* 1151 * In order to do checksumming faster we do 'end-around carry' here 1152 * (and not in for{} loop), though it implies we are not going to 1153 * reassemble more than 64k fragments. 1154 */ 1155 m->m_pkthdr.csum_data = 1156 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1157 #ifdef MAC 1158 mac_ipq_reassemble(fp, m); 1159 mac_ipq_destroy(fp); 1160 #endif 1161 1162 /* 1163 * Create header for new ip packet by modifying header of first 1164 * packet; dequeue and discard fragment reassembly header. 1165 * Make header visible. 1166 */ 1167 ip->ip_len = (ip->ip_hl << 2) + next; 1168 ip->ip_src = fp->ipq_src; 1169 ip->ip_dst = fp->ipq_dst; 1170 TAILQ_REMOVE(head, fp, ipq_list); 1171 V_nipq--; 1172 uma_zfree(V_ipq_zone, fp); 1173 m->m_len += (ip->ip_hl << 2); 1174 m->m_data -= (ip->ip_hl << 2); 1175 /* some debugging cruft by sklower, below, will go away soon */ 1176 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1177 m_fixhdr(m); 1178 IPSTAT_INC(ips_reassembled); 1179 IPQ_UNLOCK(); 1180 return (m); 1181 1182 dropfrag: 1183 IPSTAT_INC(ips_fragdropped); 1184 if (fp != NULL) 1185 fp->ipq_nfrags--; 1186 m_freem(m); 1187 done: 1188 IPQ_UNLOCK(); 1189 return (NULL); 1190 1191 #undef GETIP 1192 } 1193 1194 /* 1195 * Free a fragment reassembly header and all 1196 * associated datagrams. 1197 */ 1198 static void 1199 ip_freef(struct ipqhead *fhp, struct ipq *fp) 1200 { 1201 struct mbuf *q; 1202 1203 IPQ_LOCK_ASSERT(); 1204 1205 while (fp->ipq_frags) { 1206 q = fp->ipq_frags; 1207 fp->ipq_frags = q->m_nextpkt; 1208 m_freem(q); 1209 } 1210 TAILQ_REMOVE(fhp, fp, ipq_list); 1211 uma_zfree(V_ipq_zone, fp); 1212 V_nipq--; 1213 } 1214 1215 /* 1216 * IP timer processing; 1217 * if a timer expires on a reassembly 1218 * queue, discard it. 1219 */ 1220 void 1221 ip_slowtimo(void) 1222 { 1223 VNET_ITERATOR_DECL(vnet_iter); 1224 struct ipq *fp; 1225 int i; 1226 1227 VNET_LIST_RLOCK_NOSLEEP(); 1228 IPQ_LOCK(); 1229 VNET_FOREACH(vnet_iter) { 1230 CURVNET_SET(vnet_iter); 1231 for (i = 0; i < IPREASS_NHASH; i++) { 1232 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) { 1233 struct ipq *fpp; 1234 1235 fpp = fp; 1236 fp = TAILQ_NEXT(fp, ipq_list); 1237 if(--fpp->ipq_ttl == 0) { 1238 IPSTAT_ADD(ips_fragtimeout, 1239 fpp->ipq_nfrags); 1240 ip_freef(&V_ipq[i], fpp); 1241 } 1242 } 1243 } 1244 /* 1245 * If we are over the maximum number of fragments 1246 * (due to the limit being lowered), drain off 1247 * enough to get down to the new limit. 1248 */ 1249 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) { 1250 for (i = 0; i < IPREASS_NHASH; i++) { 1251 while (V_nipq > V_maxnipq && 1252 !TAILQ_EMPTY(&V_ipq[i])) { 1253 IPSTAT_ADD(ips_fragdropped, 1254 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1255 ip_freef(&V_ipq[i], 1256 TAILQ_FIRST(&V_ipq[i])); 1257 } 1258 } 1259 } 1260 CURVNET_RESTORE(); 1261 } 1262 IPQ_UNLOCK(); 1263 VNET_LIST_RUNLOCK_NOSLEEP(); 1264 } 1265 1266 /* 1267 * Drain off all datagram fragments. 1268 */ 1269 static void 1270 ip_drain_locked(void) 1271 { 1272 int i; 1273 1274 IPQ_LOCK_ASSERT(); 1275 1276 for (i = 0; i < IPREASS_NHASH; i++) { 1277 while(!TAILQ_EMPTY(&V_ipq[i])) { 1278 IPSTAT_ADD(ips_fragdropped, 1279 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1280 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i])); 1281 } 1282 } 1283 } 1284 1285 void 1286 ip_drain(void) 1287 { 1288 VNET_ITERATOR_DECL(vnet_iter); 1289 1290 VNET_LIST_RLOCK_NOSLEEP(); 1291 IPQ_LOCK(); 1292 VNET_FOREACH(vnet_iter) { 1293 CURVNET_SET(vnet_iter); 1294 ip_drain_locked(); 1295 CURVNET_RESTORE(); 1296 } 1297 IPQ_UNLOCK(); 1298 VNET_LIST_RUNLOCK_NOSLEEP(); 1299 in_rtqdrain(); 1300 } 1301 1302 /* 1303 * The protocol to be inserted into ip_protox[] must be already registered 1304 * in inetsw[], either statically or through pf_proto_register(). 1305 */ 1306 int 1307 ipproto_register(u_char ipproto) 1308 { 1309 struct protosw *pr; 1310 1311 /* Sanity checks. */ 1312 if (ipproto == 0) 1313 return (EPROTONOSUPPORT); 1314 1315 /* 1316 * The protocol slot must not be occupied by another protocol 1317 * already. An index pointing to IPPROTO_RAW is unused. 1318 */ 1319 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1320 if (pr == NULL) 1321 return (EPFNOSUPPORT); 1322 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1323 return (EEXIST); 1324 1325 /* Find the protocol position in inetsw[] and set the index. */ 1326 for (pr = inetdomain.dom_protosw; 1327 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1328 if (pr->pr_domain->dom_family == PF_INET && 1329 pr->pr_protocol && pr->pr_protocol == ipproto) { 1330 /* Be careful to only index valid IP protocols. */ 1331 if (pr->pr_protocol < IPPROTO_MAX) { 1332 ip_protox[pr->pr_protocol] = pr - inetsw; 1333 return (0); 1334 } else 1335 return (EINVAL); 1336 } 1337 } 1338 return (EPROTONOSUPPORT); 1339 } 1340 1341 int 1342 ipproto_unregister(u_char ipproto) 1343 { 1344 struct protosw *pr; 1345 1346 /* Sanity checks. */ 1347 if (ipproto == 0) 1348 return (EPROTONOSUPPORT); 1349 1350 /* Check if the protocol was indeed registered. */ 1351 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1352 if (pr == NULL) 1353 return (EPFNOSUPPORT); 1354 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1355 return (ENOENT); 1356 1357 /* Reset the protocol slot to IPPROTO_RAW. */ 1358 ip_protox[ipproto] = pr - inetsw; 1359 return (0); 1360 } 1361 1362 /* 1363 * Given address of next destination (final or next hop), return (referenced) 1364 * internet address info of interface to be used to get there. 1365 */ 1366 struct in_ifaddr * 1367 ip_rtaddr(struct in_addr dst, u_int fibnum) 1368 { 1369 struct route sro; 1370 struct sockaddr_in *sin; 1371 struct in_ifaddr *ia; 1372 1373 bzero(&sro, sizeof(sro)); 1374 sin = (struct sockaddr_in *)&sro.ro_dst; 1375 sin->sin_family = AF_INET; 1376 sin->sin_len = sizeof(*sin); 1377 sin->sin_addr = dst; 1378 in_rtalloc_ign(&sro, 0, fibnum); 1379 1380 if (sro.ro_rt == NULL) 1381 return (NULL); 1382 1383 ia = ifatoia(sro.ro_rt->rt_ifa); 1384 ifa_ref(&ia->ia_ifa); 1385 RTFREE(sro.ro_rt); 1386 return (ia); 1387 } 1388 1389 u_char inetctlerrmap[PRC_NCMDS] = { 1390 0, 0, 0, 0, 1391 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1392 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1393 EMSGSIZE, EHOSTUNREACH, 0, 0, 1394 0, 0, EHOSTUNREACH, 0, 1395 ENOPROTOOPT, ECONNREFUSED 1396 }; 1397 1398 /* 1399 * Forward a packet. If some error occurs return the sender 1400 * an icmp packet. Note we can't always generate a meaningful 1401 * icmp message because icmp doesn't have a large enough repertoire 1402 * of codes and types. 1403 * 1404 * If not forwarding, just drop the packet. This could be confusing 1405 * if ipforwarding was zero but some routing protocol was advancing 1406 * us as a gateway to somewhere. However, we must let the routing 1407 * protocol deal with that. 1408 * 1409 * The srcrt parameter indicates whether the packet is being forwarded 1410 * via a source route. 1411 */ 1412 void 1413 ip_forward(struct mbuf *m, int srcrt) 1414 { 1415 struct ip *ip = mtod(m, struct ip *); 1416 struct in_ifaddr *ia; 1417 struct mbuf *mcopy; 1418 struct in_addr dest; 1419 struct route ro; 1420 int error, type = 0, code = 0, mtu = 0; 1421 1422 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1423 IPSTAT_INC(ips_cantforward); 1424 m_freem(m); 1425 return; 1426 } 1427 #ifdef IPSTEALTH 1428 if (!V_ipstealth) { 1429 #endif 1430 if (ip->ip_ttl <= IPTTLDEC) { 1431 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1432 0, 0); 1433 return; 1434 } 1435 #ifdef IPSTEALTH 1436 } 1437 #endif 1438 1439 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m)); 1440 #ifndef IPSEC 1441 /* 1442 * 'ia' may be NULL if there is no route for this destination. 1443 * In case of IPsec, Don't discard it just yet, but pass it to 1444 * ip_output in case of outgoing IPsec policy. 1445 */ 1446 if (!srcrt && ia == NULL) { 1447 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1448 return; 1449 } 1450 #endif 1451 1452 /* 1453 * Save the IP header and at most 8 bytes of the payload, 1454 * in case we need to generate an ICMP message to the src. 1455 * 1456 * XXX this can be optimized a lot by saving the data in a local 1457 * buffer on the stack (72 bytes at most), and only allocating the 1458 * mbuf if really necessary. The vast majority of the packets 1459 * are forwarded without having to send an ICMP back (either 1460 * because unnecessary, or because rate limited), so we are 1461 * really we are wasting a lot of work here. 1462 * 1463 * We don't use m_copy() because it might return a reference 1464 * to a shared cluster. Both this function and ip_output() 1465 * assume exclusive access to the IP header in `m', so any 1466 * data in a cluster may change before we reach icmp_error(). 1467 */ 1468 MGETHDR(mcopy, M_DONTWAIT, m->m_type); 1469 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1470 /* 1471 * It's probably ok if the pkthdr dup fails (because 1472 * the deep copy of the tag chain failed), but for now 1473 * be conservative and just discard the copy since 1474 * code below may some day want the tags. 1475 */ 1476 m_free(mcopy); 1477 mcopy = NULL; 1478 } 1479 if (mcopy != NULL) { 1480 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy)); 1481 mcopy->m_pkthdr.len = mcopy->m_len; 1482 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1483 } 1484 1485 #ifdef IPSTEALTH 1486 if (!V_ipstealth) { 1487 #endif 1488 ip->ip_ttl -= IPTTLDEC; 1489 #ifdef IPSTEALTH 1490 } 1491 #endif 1492 1493 /* 1494 * If forwarding packet using same interface that it came in on, 1495 * perhaps should send a redirect to sender to shortcut a hop. 1496 * Only send redirect if source is sending directly to us, 1497 * and if packet was not source routed (or has any options). 1498 * Also, don't send redirect if forwarding using a default route 1499 * or a route modified by a redirect. 1500 */ 1501 dest.s_addr = 0; 1502 if (!srcrt && V_ipsendredirects && 1503 ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) { 1504 struct sockaddr_in *sin; 1505 struct rtentry *rt; 1506 1507 bzero(&ro, sizeof(ro)); 1508 sin = (struct sockaddr_in *)&ro.ro_dst; 1509 sin->sin_family = AF_INET; 1510 sin->sin_len = sizeof(*sin); 1511 sin->sin_addr = ip->ip_dst; 1512 in_rtalloc_ign(&ro, 0, M_GETFIB(m)); 1513 1514 rt = ro.ro_rt; 1515 1516 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1517 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1518 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1519 u_long src = ntohl(ip->ip_src.s_addr); 1520 1521 if (RTA(rt) && 1522 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1523 if (rt->rt_flags & RTF_GATEWAY) 1524 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1525 else 1526 dest.s_addr = ip->ip_dst.s_addr; 1527 /* Router requirements says to only send host redirects */ 1528 type = ICMP_REDIRECT; 1529 code = ICMP_REDIRECT_HOST; 1530 } 1531 } 1532 if (rt) 1533 RTFREE(rt); 1534 } 1535 1536 /* 1537 * Try to cache the route MTU from ip_output so we can consider it for 1538 * the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191. 1539 */ 1540 bzero(&ro, sizeof(ro)); 1541 1542 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL); 1543 1544 if (error == EMSGSIZE && ro.ro_rt) 1545 mtu = ro.ro_rt->rt_rmx.rmx_mtu; 1546 if (ro.ro_rt) 1547 RTFREE(ro.ro_rt); 1548 1549 if (error) 1550 IPSTAT_INC(ips_cantforward); 1551 else { 1552 IPSTAT_INC(ips_forward); 1553 if (type) 1554 IPSTAT_INC(ips_redirectsent); 1555 else { 1556 if (mcopy) 1557 m_freem(mcopy); 1558 if (ia != NULL) 1559 ifa_free(&ia->ia_ifa); 1560 return; 1561 } 1562 } 1563 if (mcopy == NULL) { 1564 if (ia != NULL) 1565 ifa_free(&ia->ia_ifa); 1566 return; 1567 } 1568 1569 switch (error) { 1570 1571 case 0: /* forwarded, but need redirect */ 1572 /* type, code set above */ 1573 break; 1574 1575 case ENETUNREACH: 1576 case EHOSTUNREACH: 1577 case ENETDOWN: 1578 case EHOSTDOWN: 1579 default: 1580 type = ICMP_UNREACH; 1581 code = ICMP_UNREACH_HOST; 1582 break; 1583 1584 case EMSGSIZE: 1585 type = ICMP_UNREACH; 1586 code = ICMP_UNREACH_NEEDFRAG; 1587 1588 #ifdef IPSEC 1589 /* 1590 * If IPsec is configured for this path, 1591 * override any possibly mtu value set by ip_output. 1592 */ 1593 mtu = ip_ipsec_mtu(mcopy, mtu); 1594 #endif /* IPSEC */ 1595 /* 1596 * If the MTU was set before make sure we are below the 1597 * interface MTU. 1598 * If the MTU wasn't set before use the interface mtu or 1599 * fall back to the next smaller mtu step compared to the 1600 * current packet size. 1601 */ 1602 if (mtu != 0) { 1603 if (ia != NULL) 1604 mtu = min(mtu, ia->ia_ifp->if_mtu); 1605 } else { 1606 if (ia != NULL) 1607 mtu = ia->ia_ifp->if_mtu; 1608 else 1609 mtu = ip_next_mtu(ip->ip_len, 0); 1610 } 1611 IPSTAT_INC(ips_cantfrag); 1612 break; 1613 1614 case ENOBUFS: 1615 /* 1616 * A router should not generate ICMP_SOURCEQUENCH as 1617 * required in RFC1812 Requirements for IP Version 4 Routers. 1618 * Source quench could be a big problem under DoS attacks, 1619 * or if the underlying interface is rate-limited. 1620 * Those who need source quench packets may re-enable them 1621 * via the net.inet.ip.sendsourcequench sysctl. 1622 */ 1623 if (V_ip_sendsourcequench == 0) { 1624 m_freem(mcopy); 1625 if (ia != NULL) 1626 ifa_free(&ia->ia_ifa); 1627 return; 1628 } else { 1629 type = ICMP_SOURCEQUENCH; 1630 code = 0; 1631 } 1632 break; 1633 1634 case EACCES: /* ipfw denied packet */ 1635 m_freem(mcopy); 1636 if (ia != NULL) 1637 ifa_free(&ia->ia_ifa); 1638 return; 1639 } 1640 if (ia != NULL) 1641 ifa_free(&ia->ia_ifa); 1642 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1643 } 1644 1645 void 1646 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1647 struct mbuf *m) 1648 { 1649 1650 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1651 struct bintime bt; 1652 1653 bintime(&bt); 1654 if (inp->inp_socket->so_options & SO_BINTIME) { 1655 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 1656 SCM_BINTIME, SOL_SOCKET); 1657 if (*mp) 1658 mp = &(*mp)->m_next; 1659 } 1660 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1661 struct timeval tv; 1662 1663 bintime2timeval(&bt, &tv); 1664 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1665 SCM_TIMESTAMP, SOL_SOCKET); 1666 if (*mp) 1667 mp = &(*mp)->m_next; 1668 } 1669 } 1670 if (inp->inp_flags & INP_RECVDSTADDR) { 1671 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1672 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1673 if (*mp) 1674 mp = &(*mp)->m_next; 1675 } 1676 if (inp->inp_flags & INP_RECVTTL) { 1677 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1678 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1679 if (*mp) 1680 mp = &(*mp)->m_next; 1681 } 1682 #ifdef notyet 1683 /* XXX 1684 * Moving these out of udp_input() made them even more broken 1685 * than they already were. 1686 */ 1687 /* options were tossed already */ 1688 if (inp->inp_flags & INP_RECVOPTS) { 1689 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1690 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1691 if (*mp) 1692 mp = &(*mp)->m_next; 1693 } 1694 /* ip_srcroute doesn't do what we want here, need to fix */ 1695 if (inp->inp_flags & INP_RECVRETOPTS) { 1696 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1697 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1698 if (*mp) 1699 mp = &(*mp)->m_next; 1700 } 1701 #endif 1702 if (inp->inp_flags & INP_RECVIF) { 1703 struct ifnet *ifp; 1704 struct sdlbuf { 1705 struct sockaddr_dl sdl; 1706 u_char pad[32]; 1707 } sdlbuf; 1708 struct sockaddr_dl *sdp; 1709 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1710 1711 if (((ifp = m->m_pkthdr.rcvif)) 1712 && ( ifp->if_index && (ifp->if_index <= V_if_index))) { 1713 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1714 /* 1715 * Change our mind and don't try copy. 1716 */ 1717 if ((sdp->sdl_family != AF_LINK) 1718 || (sdp->sdl_len > sizeof(sdlbuf))) { 1719 goto makedummy; 1720 } 1721 bcopy(sdp, sdl2, sdp->sdl_len); 1722 } else { 1723 makedummy: 1724 sdl2->sdl_len 1725 = offsetof(struct sockaddr_dl, sdl_data[0]); 1726 sdl2->sdl_family = AF_LINK; 1727 sdl2->sdl_index = 0; 1728 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1729 } 1730 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1731 IP_RECVIF, IPPROTO_IP); 1732 if (*mp) 1733 mp = &(*mp)->m_next; 1734 } 1735 } 1736 1737 /* 1738 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the 1739 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on 1740 * locking. This code remains in ip_input.c as ip_mroute.c is optionally 1741 * compiled. 1742 */ 1743 int 1744 ip_rsvp_init(struct socket *so) 1745 { 1746 1747 if (so->so_type != SOCK_RAW || 1748 so->so_proto->pr_protocol != IPPROTO_RSVP) 1749 return EOPNOTSUPP; 1750 1751 if (V_ip_rsvpd != NULL) 1752 return EADDRINUSE; 1753 1754 V_ip_rsvpd = so; 1755 /* 1756 * This may seem silly, but we need to be sure we don't over-increment 1757 * the RSVP counter, in case something slips up. 1758 */ 1759 if (!V_ip_rsvp_on) { 1760 V_ip_rsvp_on = 1; 1761 V_rsvp_on++; 1762 } 1763 1764 return 0; 1765 } 1766 1767 int 1768 ip_rsvp_done(void) 1769 { 1770 1771 V_ip_rsvpd = NULL; 1772 /* 1773 * This may seem silly, but we need to be sure we don't over-decrement 1774 * the RSVP counter, in case something slips up. 1775 */ 1776 if (V_ip_rsvp_on) { 1777 V_ip_rsvp_on = 0; 1778 V_rsvp_on--; 1779 } 1780 return 0; 1781 } 1782 1783 void 1784 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1785 { 1786 1787 if (rsvp_input_p) { /* call the real one if loaded */ 1788 rsvp_input_p(m, off); 1789 return; 1790 } 1791 1792 /* Can still get packets with rsvp_on = 0 if there is a local member 1793 * of the group to which the RSVP packet is addressed. But in this 1794 * case we want to throw the packet away. 1795 */ 1796 1797 if (!V_rsvp_on) { 1798 m_freem(m); 1799 return; 1800 } 1801 1802 if (V_ip_rsvpd != NULL) { 1803 rip_input(m, off); 1804 return; 1805 } 1806 /* Drop the packet */ 1807 m_freem(m); 1808 } 1809