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sys/netinet/ip_input.c
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1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD: releng/10.4/sys/netinet/ip_input.c 300518 2016-05-23 16:20:50Z loos $"); 34 35 #include "opt_bootp.h" 36 #include "opt_ipfw.h" 37 #include "opt_ipstealth.h" 38 #include "opt_ipsec.h" 39 #include "opt_kdtrace.h" 40 #include "opt_route.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/mbuf.h> 45 #include <sys/malloc.h> 46 #include <sys/domain.h> 47 #include <sys/protosw.h> 48 #include <sys/socket.h> 49 #include <sys/time.h> 50 #include <sys/kernel.h> 51 #include <sys/lock.h> 52 #include <sys/rwlock.h> 53 #include <sys/sdt.h> 54 #include <sys/syslog.h> 55 #include <sys/sysctl.h> 56 57 #include <net/pfil.h> 58 #include <net/if.h> 59 #include <net/if_types.h> 60 #include <net/if_var.h> 61 #include <net/if_dl.h> 62 #include <net/route.h> 63 #include <net/netisr.h> 64 #include <net/vnet.h> 65 66 #include <netinet/in.h> 67 #include <netinet/in_kdtrace.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 #include <netinet/ip_carp.h> 78 #ifdef IPSEC 79 #include <netinet/ip_ipsec.h> 80 #endif /* IPSEC */ 81 82 #include <sys/socketvar.h> 83 84 #include <security/mac/mac_framework.h> 85 86 #ifdef CTASSERT 87 CTASSERT(sizeof(struct ip) == 20); 88 #endif 89 90 struct rwlock in_ifaddr_lock; 91 RW_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock"); 92 93 VNET_DEFINE(int, rsvp_on); 94 95 VNET_DEFINE(int, ipforwarding); 96 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 97 &VNET_NAME(ipforwarding), 0, 98 "Enable IP forwarding between interfaces"); 99 100 static VNET_DEFINE(int, ipsendredirects) = 1; /* XXX */ 101 #define V_ipsendredirects VNET(ipsendredirects) 102 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 103 &VNET_NAME(ipsendredirects), 0, 104 "Enable sending IP redirects"); 105 106 static VNET_DEFINE(int, ip_keepfaith); 107 #define V_ip_keepfaith VNET(ip_keepfaith) 108 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 109 &VNET_NAME(ip_keepfaith), 0, 110 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 111 112 static VNET_DEFINE(int, ip_sendsourcequench); 113 #define V_ip_sendsourcequench VNET(ip_sendsourcequench) 114 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 115 &VNET_NAME(ip_sendsourcequench), 0, 116 "Enable the transmission of source quench packets"); 117 118 VNET_DEFINE(int, ip_do_randomid); 119 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 120 &VNET_NAME(ip_do_randomid), 0, 121 "Assign random ip_id values"); 122 123 /* 124 * XXX - Setting ip_checkinterface mostly implements the receive side of 125 * the Strong ES model described in RFC 1122, but since the routing table 126 * and transmit implementation do not implement the Strong ES model, 127 * setting this to 1 results in an odd hybrid. 128 * 129 * XXX - ip_checkinterface currently must be disabled if you use ipnat 130 * to translate the destination address to another local interface. 131 * 132 * XXX - ip_checkinterface must be disabled if you add IP aliases 133 * to the loopback interface instead of the interface where the 134 * packets for those addresses are received. 135 */ 136 static VNET_DEFINE(int, ip_checkinterface); 137 #define V_ip_checkinterface VNET(ip_checkinterface) 138 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 139 &VNET_NAME(ip_checkinterface), 0, 140 "Verify packet arrives on correct interface"); 141 142 VNET_DEFINE(struct pfil_head, inet_pfil_hook); /* Packet filter hooks */ 143 144 static struct netisr_handler ip_nh = { 145 .nh_name = "ip", 146 .nh_handler = ip_input, 147 .nh_proto = NETISR_IP, 148 .nh_policy = NETISR_POLICY_FLOW, 149 }; 150 151 extern struct domain inetdomain; 152 extern struct protosw inetsw[]; 153 u_char ip_protox[IPPROTO_MAX]; 154 VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */ 155 VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */ 156 VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */ 157 158 static VNET_DEFINE(uma_zone_t, ipq_zone); 159 static VNET_DEFINE(TAILQ_HEAD(ipqhead, ipq), ipq[IPREASS_NHASH]); 160 static struct mtx ipqlock; 161 162 #define V_ipq_zone VNET(ipq_zone) 163 #define V_ipq VNET(ipq) 164 165 #define IPQ_LOCK() mtx_lock(&ipqlock) 166 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 167 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 168 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 169 170 static void maxnipq_update(void); 171 static void ipq_zone_change(void *); 172 static void ip_drain_locked(void); 173 174 static VNET_DEFINE(int, maxnipq); /* Administrative limit on # reass queues. */ 175 static VNET_DEFINE(int, nipq); /* Total # of reass queues */ 176 #define V_maxnipq VNET(maxnipq) 177 #define V_nipq VNET(nipq) 178 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, 179 &VNET_NAME(nipq), 0, 180 "Current number of IPv4 fragment reassembly queue entries"); 181 182 static VNET_DEFINE(int, maxfragsperpacket); 183 #define V_maxfragsperpacket VNET(maxfragsperpacket) 184 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 185 &VNET_NAME(maxfragsperpacket), 0, 186 "Maximum number of IPv4 fragments allowed per packet"); 187 188 #ifdef IPCTL_DEFMTU 189 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 190 &ip_mtu, 0, "Default MTU"); 191 #endif 192 193 #ifdef IPSTEALTH 194 VNET_DEFINE(int, ipstealth); 195 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 196 &VNET_NAME(ipstealth), 0, 197 "IP stealth mode, no TTL decrementation on forwarding"); 198 #endif 199 200 static void ip_freef(struct ipqhead *, struct ipq *); 201 202 /* 203 * IP statistics are stored in the "array" of counter(9)s. 204 */ 205 VNET_PCPUSTAT_DEFINE(struct ipstat, ipstat); 206 VNET_PCPUSTAT_SYSINIT(ipstat); 207 SYSCTL_VNET_PCPUSTAT(_net_inet_ip, IPCTL_STATS, stats, struct ipstat, ipstat, 208 "IP statistics (struct ipstat, netinet/ip_var.h)"); 209 210 #ifdef VIMAGE 211 VNET_PCPUSTAT_SYSUNINIT(ipstat); 212 #endif /* VIMAGE */ 213 214 /* 215 * Kernel module interface for updating ipstat. The argument is an index 216 * into ipstat treated as an array. 217 */ 218 void 219 kmod_ipstat_inc(int statnum) 220 { 221 222 counter_u64_add(VNET(ipstat)[statnum], 1); 223 } 224 225 void 226 kmod_ipstat_dec(int statnum) 227 { 228 229 counter_u64_add(VNET(ipstat)[statnum], -1); 230 } 231 232 static int 233 sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS) 234 { 235 int error, qlimit; 236 237 netisr_getqlimit(&ip_nh, &qlimit); 238 error = sysctl_handle_int(oidp, &qlimit, 0, req); 239 if (error || !req->newptr) 240 return (error); 241 if (qlimit < 1) 242 return (EINVAL); 243 return (netisr_setqlimit(&ip_nh, qlimit)); 244 } 245 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, 246 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I", 247 "Maximum size of the IP input queue"); 248 249 static int 250 sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS) 251 { 252 u_int64_t qdrops_long; 253 int error, qdrops; 254 255 netisr_getqdrops(&ip_nh, &qdrops_long); 256 qdrops = qdrops_long; 257 error = sysctl_handle_int(oidp, &qdrops, 0, req); 258 if (error || !req->newptr) 259 return (error); 260 if (qdrops != 0) 261 return (EINVAL); 262 netisr_clearqdrops(&ip_nh); 263 return (0); 264 } 265 266 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, 267 CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I", 268 "Number of packets dropped from the IP input queue"); 269 270 /* 271 * IP initialization: fill in IP protocol switch table. 272 * All protocols not implemented in kernel go to raw IP protocol handler. 273 */ 274 void 275 ip_init(void) 276 { 277 struct protosw *pr; 278 int i; 279 280 V_ip_id = time_second & 0xffff; 281 282 TAILQ_INIT(&V_in_ifaddrhead); 283 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask); 284 285 /* Initialize IP reassembly queue. */ 286 for (i = 0; i < IPREASS_NHASH; i++) 287 TAILQ_INIT(&V_ipq[i]); 288 V_maxnipq = nmbclusters / 32; 289 V_maxfragsperpacket = 16; 290 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 291 NULL, UMA_ALIGN_PTR, 0); 292 maxnipq_update(); 293 294 /* Initialize packet filter hooks. */ 295 V_inet_pfil_hook.ph_type = PFIL_TYPE_AF; 296 V_inet_pfil_hook.ph_af = AF_INET; 297 if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0) 298 printf("%s: WARNING: unable to register pfil hook, " 299 "error %d\n", __func__, i); 300 301 /* Skip initialization of globals for non-default instances. */ 302 if (!IS_DEFAULT_VNET(curvnet)) 303 return; 304 305 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 306 if (pr == NULL) 307 panic("ip_init: PF_INET not found"); 308 309 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 310 for (i = 0; i < IPPROTO_MAX; i++) 311 ip_protox[i] = pr - inetsw; 312 /* 313 * Cycle through IP protocols and put them into the appropriate place 314 * in ip_protox[]. 315 */ 316 for (pr = inetdomain.dom_protosw; 317 pr < inetdomain.dom_protoswNPROTOSW; pr++) 318 if (pr->pr_domain->dom_family == PF_INET && 319 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 320 /* Be careful to only index valid IP protocols. */ 321 if (pr->pr_protocol < IPPROTO_MAX) 322 ip_protox[pr->pr_protocol] = pr - inetsw; 323 } 324 325 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, 326 NULL, EVENTHANDLER_PRI_ANY); 327 328 /* Initialize various other remaining things. */ 329 IPQ_LOCK_INIT(); 330 netisr_register(&ip_nh); 331 } 332 333 #ifdef VIMAGE 334 void 335 ip_destroy(void) 336 { 337 int i; 338 339 if ((i = pfil_head_unregister(&V_inet_pfil_hook)) != 0) 340 printf("%s: WARNING: unable to unregister pfil hook, " 341 "error %d\n", __func__, i); 342 343 /* Cleanup in_ifaddr hash table; should be empty. */ 344 hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask); 345 346 IPQ_LOCK(); 347 ip_drain_locked(); 348 IPQ_UNLOCK(); 349 350 uma_zdestroy(V_ipq_zone); 351 } 352 #endif 353 354 /* 355 * Ip input routine. Checksum and byte swap header. If fragmented 356 * try to reassemble. Process options. Pass to next level. 357 */ 358 void 359 ip_input(struct mbuf *m) 360 { 361 struct ip *ip = NULL; 362 struct in_ifaddr *ia = NULL; 363 struct ifaddr *ifa; 364 struct ifnet *ifp; 365 int checkif, hlen = 0; 366 uint16_t sum, ip_len; 367 int dchg = 0; /* dest changed after fw */ 368 struct in_addr odst; /* original dst address */ 369 370 M_ASSERTPKTHDR(m); 371 372 if (m->m_flags & M_FASTFWD_OURS) { 373 m->m_flags &= ~M_FASTFWD_OURS; 374 /* Set up some basics that will be used later. */ 375 ip = mtod(m, struct ip *); 376 hlen = ip->ip_hl << 2; 377 ip_len = ntohs(ip->ip_len); 378 goto ours; 379 } 380 381 IPSTAT_INC(ips_total); 382 383 if (m->m_pkthdr.len < sizeof(struct ip)) 384 goto tooshort; 385 386 if (m->m_len < sizeof (struct ip) && 387 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 388 IPSTAT_INC(ips_toosmall); 389 return; 390 } 391 ip = mtod(m, struct ip *); 392 393 if (ip->ip_v != IPVERSION) { 394 IPSTAT_INC(ips_badvers); 395 goto bad; 396 } 397 398 hlen = ip->ip_hl << 2; 399 if (hlen < sizeof(struct ip)) { /* minimum header length */ 400 IPSTAT_INC(ips_badhlen); 401 goto bad; 402 } 403 if (hlen > m->m_len) { 404 if ((m = m_pullup(m, hlen)) == NULL) { 405 IPSTAT_INC(ips_badhlen); 406 return; 407 } 408 ip = mtod(m, struct ip *); 409 } 410 411 IP_PROBE(receive, NULL, NULL, ip, m->m_pkthdr.rcvif, ip, NULL); 412 413 /* 127/8 must not appear on wire - RFC1122 */ 414 ifp = m->m_pkthdr.rcvif; 415 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 416 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 417 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 418 IPSTAT_INC(ips_badaddr); 419 goto bad; 420 } 421 } 422 423 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 424 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 425 } else { 426 if (hlen == sizeof(struct ip)) { 427 sum = in_cksum_hdr(ip); 428 } else { 429 sum = in_cksum(m, hlen); 430 } 431 } 432 if (sum) { 433 IPSTAT_INC(ips_badsum); 434 goto bad; 435 } 436 437 #ifdef ALTQ 438 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 439 /* packet is dropped by traffic conditioner */ 440 return; 441 #endif 442 443 ip_len = ntohs(ip->ip_len); 444 if (ip_len < hlen) { 445 IPSTAT_INC(ips_badlen); 446 goto bad; 447 } 448 449 /* 450 * Check that the amount of data in the buffers 451 * is as at least much as the IP header would have us expect. 452 * Trim mbufs if longer than we expect. 453 * Drop packet if shorter than we expect. 454 */ 455 if (m->m_pkthdr.len < ip_len) { 456 tooshort: 457 IPSTAT_INC(ips_tooshort); 458 goto bad; 459 } 460 if (m->m_pkthdr.len > ip_len) { 461 if (m->m_len == m->m_pkthdr.len) { 462 m->m_len = ip_len; 463 m->m_pkthdr.len = ip_len; 464 } else 465 m_adj(m, ip_len - m->m_pkthdr.len); 466 } 467 #ifdef IPSEC 468 /* 469 * Bypass packet filtering for packets previously handled by IPsec. 470 */ 471 if (ip_ipsec_filtertunnel(m)) 472 goto passin; 473 #endif /* IPSEC */ 474 475 /* 476 * Run through list of hooks for input packets. 477 * 478 * NB: Beware of the destination address changing (e.g. 479 * by NAT rewriting). When this happens, tell 480 * ip_forward to do the right thing. 481 */ 482 483 /* Jump over all PFIL processing if hooks are not active. */ 484 if (!PFIL_HOOKED(&V_inet_pfil_hook)) 485 goto passin; 486 487 odst = ip->ip_dst; 488 if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0) 489 return; 490 if (m == NULL) /* consumed by filter */ 491 return; 492 493 ip = mtod(m, struct ip *); 494 dchg = (odst.s_addr != ip->ip_dst.s_addr); 495 ifp = m->m_pkthdr.rcvif; 496 497 if (m->m_flags & M_FASTFWD_OURS) { 498 m->m_flags &= ~M_FASTFWD_OURS; 499 goto ours; 500 } 501 if (m->m_flags & M_IP_NEXTHOP) { 502 if (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL) { 503 /* 504 * Directly ship the packet on. This allows 505 * forwarding packets originally destined to us 506 * to some other directly connected host. 507 */ 508 ip_forward(m, 1); 509 return; 510 } 511 } 512 passin: 513 514 /* 515 * Process options and, if not destined for us, 516 * ship it on. ip_dooptions returns 1 when an 517 * error was detected (causing an icmp message 518 * to be sent and the original packet to be freed). 519 */ 520 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 521 return; 522 523 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 524 * matter if it is destined to another node, or whether it is 525 * a multicast one, RSVP wants it! and prevents it from being forwarded 526 * anywhere else. Also checks if the rsvp daemon is running before 527 * grabbing the packet. 528 */ 529 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP) 530 goto ours; 531 532 /* 533 * Check our list of addresses, to see if the packet is for us. 534 * If we don't have any addresses, assume any unicast packet 535 * we receive might be for us (and let the upper layers deal 536 * with it). 537 */ 538 if (TAILQ_EMPTY(&V_in_ifaddrhead) && 539 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 540 goto ours; 541 542 /* 543 * Enable a consistency check between the destination address 544 * and the arrival interface for a unicast packet (the RFC 1122 545 * strong ES model) if IP forwarding is disabled and the packet 546 * is not locally generated and the packet is not subject to 547 * 'ipfw fwd'. 548 * 549 * XXX - Checking also should be disabled if the destination 550 * address is ipnat'ed to a different interface. 551 * 552 * XXX - Checking is incompatible with IP aliases added 553 * to the loopback interface instead of the interface where 554 * the packets are received. 555 * 556 * XXX - This is the case for carp vhost IPs as well so we 557 * insert a workaround. If the packet got here, we already 558 * checked with carp_iamatch() and carp_forus(). 559 */ 560 checkif = V_ip_checkinterface && (V_ipforwarding == 0) && 561 ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) && 562 ifp->if_carp == NULL && (dchg == 0); 563 564 /* 565 * Check for exact addresses in the hash bucket. 566 */ 567 /* IN_IFADDR_RLOCK(); */ 568 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 569 /* 570 * If the address matches, verify that the packet 571 * arrived via the correct interface if checking is 572 * enabled. 573 */ 574 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 575 (!checkif || ia->ia_ifp == ifp)) { 576 ifa_ref(&ia->ia_ifa); 577 /* IN_IFADDR_RUNLOCK(); */ 578 goto ours; 579 } 580 } 581 /* IN_IFADDR_RUNLOCK(); */ 582 583 /* 584 * Check for broadcast addresses. 585 * 586 * Only accept broadcast packets that arrive via the matching 587 * interface. Reception of forwarded directed broadcasts would 588 * be handled via ip_forward() and ether_output() with the loopback 589 * into the stack for SIMPLEX interfaces handled by ether_output(). 590 */ 591 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) { 592 IF_ADDR_RLOCK(ifp); 593 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 594 if (ifa->ifa_addr->sa_family != AF_INET) 595 continue; 596 ia = ifatoia(ifa); 597 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 598 ip->ip_dst.s_addr) { 599 ifa_ref(ifa); 600 IF_ADDR_RUNLOCK(ifp); 601 goto ours; 602 } 603 #ifdef BOOTP_COMPAT 604 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) { 605 ifa_ref(ifa); 606 IF_ADDR_RUNLOCK(ifp); 607 goto ours; 608 } 609 #endif 610 } 611 IF_ADDR_RUNLOCK(ifp); 612 ia = NULL; 613 } 614 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */ 615 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) { 616 IPSTAT_INC(ips_cantforward); 617 m_freem(m); 618 return; 619 } 620 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 621 if (V_ip_mrouter) { 622 /* 623 * If we are acting as a multicast router, all 624 * incoming multicast packets are passed to the 625 * kernel-level multicast forwarding function. 626 * The packet is returned (relatively) intact; if 627 * ip_mforward() returns a non-zero value, the packet 628 * must be discarded, else it may be accepted below. 629 */ 630 if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) { 631 IPSTAT_INC(ips_cantforward); 632 m_freem(m); 633 return; 634 } 635 636 /* 637 * The process-level routing daemon needs to receive 638 * all multicast IGMP packets, whether or not this 639 * host belongs to their destination groups. 640 */ 641 if (ip->ip_p == IPPROTO_IGMP) 642 goto ours; 643 IPSTAT_INC(ips_forward); 644 } 645 /* 646 * Assume the packet is for us, to avoid prematurely taking 647 * a lock on the in_multi hash. Protocols must perform 648 * their own filtering and update statistics accordingly. 649 */ 650 goto ours; 651 } 652 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 653 goto ours; 654 if (ip->ip_dst.s_addr == INADDR_ANY) 655 goto ours; 656 657 /* 658 * FAITH(Firewall Aided Internet Translator) 659 */ 660 if (ifp && ifp->if_type == IFT_FAITH) { 661 if (V_ip_keepfaith) { 662 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 663 goto ours; 664 } 665 m_freem(m); 666 return; 667 } 668 669 /* 670 * Not for us; forward if possible and desirable. 671 */ 672 if (V_ipforwarding == 0) { 673 IPSTAT_INC(ips_cantforward); 674 m_freem(m); 675 } else { 676 #ifdef IPSEC 677 if (ip_ipsec_fwd(m)) 678 goto bad; 679 #endif /* IPSEC */ 680 ip_forward(m, dchg); 681 } 682 return; 683 684 ours: 685 #ifdef IPSTEALTH 686 /* 687 * IPSTEALTH: Process non-routing options only 688 * if the packet is destined for us. 689 */ 690 if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1)) { 691 if (ia != NULL) 692 ifa_free(&ia->ia_ifa); 693 return; 694 } 695 #endif /* IPSTEALTH */ 696 697 /* Count the packet in the ip address stats */ 698 if (ia != NULL) { 699 ia->ia_ifa.if_ipackets++; 700 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 701 ifa_free(&ia->ia_ifa); 702 } 703 704 /* 705 * Attempt reassembly; if it succeeds, proceed. 706 * ip_reass() will return a different mbuf. 707 */ 708 if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) { 709 /* XXXGL: shouldn't we save & set m_flags? */ 710 m = ip_reass(m); 711 if (m == NULL) 712 return; 713 ip = mtod(m, struct ip *); 714 /* Get the header length of the reassembled packet */ 715 hlen = ip->ip_hl << 2; 716 } 717 718 #ifdef IPSEC 719 /* 720 * enforce IPsec policy checking if we are seeing last header. 721 * note that we do not visit this with protocols with pcb layer 722 * code - like udp/tcp/raw ip. 723 */ 724 if (ip_ipsec_input(m)) 725 goto bad; 726 #endif /* IPSEC */ 727 728 /* 729 * Switch out to protocol's input routine. 730 */ 731 IPSTAT_INC(ips_delivered); 732 733 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 734 return; 735 bad: 736 m_freem(m); 737 } 738 739 /* 740 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 741 * max has slightly different semantics than the sysctl, for historical 742 * reasons. 743 */ 744 static void 745 maxnipq_update(void) 746 { 747 748 /* 749 * -1 for unlimited allocation. 750 */ 751 if (V_maxnipq < 0) 752 uma_zone_set_max(V_ipq_zone, 0); 753 /* 754 * Positive number for specific bound. 755 */ 756 if (V_maxnipq > 0) 757 uma_zone_set_max(V_ipq_zone, V_maxnipq); 758 /* 759 * Zero specifies no further fragment queue allocation -- set the 760 * bound very low, but rely on implementation elsewhere to actually 761 * prevent allocation and reclaim current queues. 762 */ 763 if (V_maxnipq == 0) 764 uma_zone_set_max(V_ipq_zone, 1); 765 } 766 767 static void 768 ipq_zone_change(void *tag) 769 { 770 771 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) { 772 V_maxnipq = nmbclusters / 32; 773 maxnipq_update(); 774 } 775 } 776 777 static int 778 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 779 { 780 int error, i; 781 782 i = V_maxnipq; 783 error = sysctl_handle_int(oidp, &i, 0, req); 784 if (error || !req->newptr) 785 return (error); 786 787 /* 788 * XXXRW: Might be a good idea to sanity check the argument and place 789 * an extreme upper bound. 790 */ 791 if (i < -1) 792 return (EINVAL); 793 V_maxnipq = i; 794 maxnipq_update(); 795 return (0); 796 } 797 798 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 799 NULL, 0, sysctl_maxnipq, "I", 800 "Maximum number of IPv4 fragment reassembly queue entries"); 801 802 #define M_IP_FRAG M_PROTO9 803 804 /* 805 * Take incoming datagram fragment and try to reassemble it into 806 * whole datagram. If the argument is the first fragment or one 807 * in between the function will return NULL and store the mbuf 808 * in the fragment chain. If the argument is the last fragment 809 * the packet will be reassembled and the pointer to the new 810 * mbuf returned for further processing. Only m_tags attached 811 * to the first packet/fragment are preserved. 812 * The IP header is *NOT* adjusted out of iplen. 813 */ 814 struct mbuf * 815 ip_reass(struct mbuf *m) 816 { 817 struct ip *ip; 818 struct mbuf *p, *q, *nq, *t; 819 struct ipq *fp = NULL; 820 struct ipqhead *head; 821 int i, hlen, next; 822 u_int8_t ecn, ecn0; 823 u_short hash; 824 825 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 826 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) { 827 IPSTAT_INC(ips_fragments); 828 IPSTAT_INC(ips_fragdropped); 829 m_freem(m); 830 return (NULL); 831 } 832 833 ip = mtod(m, struct ip *); 834 hlen = ip->ip_hl << 2; 835 836 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 837 head = &V_ipq[hash]; 838 IPQ_LOCK(); 839 840 /* 841 * Look for queue of fragments 842 * of this datagram. 843 */ 844 TAILQ_FOREACH(fp, head, ipq_list) 845 if (ip->ip_id == fp->ipq_id && 846 ip->ip_src.s_addr == fp->ipq_src.s_addr && 847 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 848 #ifdef MAC 849 mac_ipq_match(m, fp) && 850 #endif 851 ip->ip_p == fp->ipq_p) 852 goto found; 853 854 fp = NULL; 855 856 /* 857 * Attempt to trim the number of allocated fragment queues if it 858 * exceeds the administrative limit. 859 */ 860 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) { 861 /* 862 * drop something from the tail of the current queue 863 * before proceeding further 864 */ 865 struct ipq *q = TAILQ_LAST(head, ipqhead); 866 if (q == NULL) { /* gak */ 867 for (i = 0; i < IPREASS_NHASH; i++) { 868 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead); 869 if (r) { 870 IPSTAT_ADD(ips_fragtimeout, 871 r->ipq_nfrags); 872 ip_freef(&V_ipq[i], r); 873 break; 874 } 875 } 876 } else { 877 IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags); 878 ip_freef(head, q); 879 } 880 } 881 882 found: 883 /* 884 * Adjust ip_len to not reflect header, 885 * convert offset of this to bytes. 886 */ 887 ip->ip_len = htons(ntohs(ip->ip_len) - hlen); 888 if (ip->ip_off & htons(IP_MF)) { 889 /* 890 * Make sure that fragments have a data length 891 * that's a non-zero multiple of 8 bytes. 892 */ 893 if (ip->ip_len == htons(0) || (ntohs(ip->ip_len) & 0x7) != 0) { 894 IPSTAT_INC(ips_toosmall); /* XXX */ 895 goto dropfrag; 896 } 897 m->m_flags |= M_IP_FRAG; 898 } else 899 m->m_flags &= ~M_IP_FRAG; 900 ip->ip_off = htons(ntohs(ip->ip_off) << 3); 901 902 /* 903 * Attempt reassembly; if it succeeds, proceed. 904 * ip_reass() will return a different mbuf. 905 */ 906 IPSTAT_INC(ips_fragments); 907 m->m_pkthdr.PH_loc.ptr = ip; 908 909 /* Previous ip_reass() started here. */ 910 /* 911 * Presence of header sizes in mbufs 912 * would confuse code below. 913 */ 914 m->m_data += hlen; 915 m->m_len -= hlen; 916 917 /* 918 * If first fragment to arrive, create a reassembly queue. 919 */ 920 if (fp == NULL) { 921 fp = uma_zalloc(V_ipq_zone, M_NOWAIT); 922 if (fp == NULL) 923 goto dropfrag; 924 #ifdef MAC 925 if (mac_ipq_init(fp, M_NOWAIT) != 0) { 926 uma_zfree(V_ipq_zone, fp); 927 fp = NULL; 928 goto dropfrag; 929 } 930 mac_ipq_create(m, fp); 931 #endif 932 TAILQ_INSERT_HEAD(head, fp, ipq_list); 933 V_nipq++; 934 fp->ipq_nfrags = 1; 935 fp->ipq_ttl = IPFRAGTTL; 936 fp->ipq_p = ip->ip_p; 937 fp->ipq_id = ip->ip_id; 938 fp->ipq_src = ip->ip_src; 939 fp->ipq_dst = ip->ip_dst; 940 fp->ipq_frags = m; 941 m->m_nextpkt = NULL; 942 goto done; 943 } else { 944 fp->ipq_nfrags++; 945 #ifdef MAC 946 mac_ipq_update(m, fp); 947 #endif 948 } 949 950 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.PH_loc.ptr)) 951 952 /* 953 * Handle ECN by comparing this segment with the first one; 954 * if CE is set, do not lose CE. 955 * drop if CE and not-ECT are mixed for the same packet. 956 */ 957 ecn = ip->ip_tos & IPTOS_ECN_MASK; 958 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 959 if (ecn == IPTOS_ECN_CE) { 960 if (ecn0 == IPTOS_ECN_NOTECT) 961 goto dropfrag; 962 if (ecn0 != IPTOS_ECN_CE) 963 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 964 } 965 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 966 goto dropfrag; 967 968 /* 969 * Find a segment which begins after this one does. 970 */ 971 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 972 if (ntohs(GETIP(q)->ip_off) > ntohs(ip->ip_off)) 973 break; 974 975 /* 976 * If there is a preceding segment, it may provide some of 977 * our data already. If so, drop the data from the incoming 978 * segment. If it provides all of our data, drop us, otherwise 979 * stick new segment in the proper place. 980 * 981 * If some of the data is dropped from the preceding 982 * segment, then it's checksum is invalidated. 983 */ 984 if (p) { 985 i = ntohs(GETIP(p)->ip_off) + ntohs(GETIP(p)->ip_len) - 986 ntohs(ip->ip_off); 987 if (i > 0) { 988 if (i >= ntohs(ip->ip_len)) 989 goto dropfrag; 990 m_adj(m, i); 991 m->m_pkthdr.csum_flags = 0; 992 ip->ip_off = htons(ntohs(ip->ip_off) + i); 993 ip->ip_len = htons(ntohs(ip->ip_len) - i); 994 } 995 m->m_nextpkt = p->m_nextpkt; 996 p->m_nextpkt = m; 997 } else { 998 m->m_nextpkt = fp->ipq_frags; 999 fp->ipq_frags = m; 1000 } 1001 1002 /* 1003 * While we overlap succeeding segments trim them or, 1004 * if they are completely covered, dequeue them. 1005 */ 1006 for (; q != NULL && ntohs(ip->ip_off) + ntohs(ip->ip_len) > 1007 ntohs(GETIP(q)->ip_off); q = nq) { 1008 i = (ntohs(ip->ip_off) + ntohs(ip->ip_len)) - 1009 ntohs(GETIP(q)->ip_off); 1010 if (i < ntohs(GETIP(q)->ip_len)) { 1011 GETIP(q)->ip_len = htons(ntohs(GETIP(q)->ip_len) - i); 1012 GETIP(q)->ip_off = htons(ntohs(GETIP(q)->ip_off) + i); 1013 m_adj(q, i); 1014 q->m_pkthdr.csum_flags = 0; 1015 break; 1016 } 1017 nq = q->m_nextpkt; 1018 m->m_nextpkt = nq; 1019 IPSTAT_INC(ips_fragdropped); 1020 fp->ipq_nfrags--; 1021 m_freem(q); 1022 } 1023 1024 /* 1025 * Check for complete reassembly and perform frag per packet 1026 * limiting. 1027 * 1028 * Frag limiting is performed here so that the nth frag has 1029 * a chance to complete the packet before we drop the packet. 1030 * As a result, n+1 frags are actually allowed per packet, but 1031 * only n will ever be stored. (n = maxfragsperpacket.) 1032 * 1033 */ 1034 next = 0; 1035 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1036 if (ntohs(GETIP(q)->ip_off) != next) { 1037 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1038 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1039 ip_freef(head, fp); 1040 } 1041 goto done; 1042 } 1043 next += ntohs(GETIP(q)->ip_len); 1044 } 1045 /* Make sure the last packet didn't have the IP_MF flag */ 1046 if (p->m_flags & M_IP_FRAG) { 1047 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1048 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1049 ip_freef(head, fp); 1050 } 1051 goto done; 1052 } 1053 1054 /* 1055 * Reassembly is complete. Make sure the packet is a sane size. 1056 */ 1057 q = fp->ipq_frags; 1058 ip = GETIP(q); 1059 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1060 IPSTAT_INC(ips_toolong); 1061 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1062 ip_freef(head, fp); 1063 goto done; 1064 } 1065 1066 /* 1067 * Concatenate fragments. 1068 */ 1069 m = q; 1070 t = m->m_next; 1071 m->m_next = NULL; 1072 m_cat(m, t); 1073 nq = q->m_nextpkt; 1074 q->m_nextpkt = NULL; 1075 for (q = nq; q != NULL; q = nq) { 1076 nq = q->m_nextpkt; 1077 q->m_nextpkt = NULL; 1078 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1079 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1080 m_cat(m, q); 1081 } 1082 /* 1083 * In order to do checksumming faster we do 'end-around carry' here 1084 * (and not in for{} loop), though it implies we are not going to 1085 * reassemble more than 64k fragments. 1086 */ 1087 while (m->m_pkthdr.csum_data & 0xffff0000) 1088 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + 1089 (m->m_pkthdr.csum_data >> 16); 1090 #ifdef MAC 1091 mac_ipq_reassemble(fp, m); 1092 mac_ipq_destroy(fp); 1093 #endif 1094 1095 /* 1096 * Create header for new ip packet by modifying header of first 1097 * packet; dequeue and discard fragment reassembly header. 1098 * Make header visible. 1099 */ 1100 ip->ip_len = htons((ip->ip_hl << 2) + next); 1101 ip->ip_src = fp->ipq_src; 1102 ip->ip_dst = fp->ipq_dst; 1103 TAILQ_REMOVE(head, fp, ipq_list); 1104 V_nipq--; 1105 uma_zfree(V_ipq_zone, fp); 1106 m->m_len += (ip->ip_hl << 2); 1107 m->m_data -= (ip->ip_hl << 2); 1108 /* some debugging cruft by sklower, below, will go away soon */ 1109 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1110 m_fixhdr(m); 1111 IPSTAT_INC(ips_reassembled); 1112 IPQ_UNLOCK(); 1113 return (m); 1114 1115 dropfrag: 1116 IPSTAT_INC(ips_fragdropped); 1117 if (fp != NULL) 1118 fp->ipq_nfrags--; 1119 m_freem(m); 1120 done: 1121 IPQ_UNLOCK(); 1122 return (NULL); 1123 1124 #undef GETIP 1125 } 1126 1127 /* 1128 * Free a fragment reassembly header and all 1129 * associated datagrams. 1130 */ 1131 static void 1132 ip_freef(struct ipqhead *fhp, struct ipq *fp) 1133 { 1134 struct mbuf *q; 1135 1136 IPQ_LOCK_ASSERT(); 1137 1138 while (fp->ipq_frags) { 1139 q = fp->ipq_frags; 1140 fp->ipq_frags = q->m_nextpkt; 1141 m_freem(q); 1142 } 1143 TAILQ_REMOVE(fhp, fp, ipq_list); 1144 uma_zfree(V_ipq_zone, fp); 1145 V_nipq--; 1146 } 1147 1148 /* 1149 * IP timer processing; 1150 * if a timer expires on a reassembly 1151 * queue, discard it. 1152 */ 1153 void 1154 ip_slowtimo(void) 1155 { 1156 VNET_ITERATOR_DECL(vnet_iter); 1157 struct ipq *fp; 1158 int i; 1159 1160 VNET_LIST_RLOCK_NOSLEEP(); 1161 IPQ_LOCK(); 1162 VNET_FOREACH(vnet_iter) { 1163 CURVNET_SET(vnet_iter); 1164 for (i = 0; i < IPREASS_NHASH; i++) { 1165 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) { 1166 struct ipq *fpp; 1167 1168 fpp = fp; 1169 fp = TAILQ_NEXT(fp, ipq_list); 1170 if(--fpp->ipq_ttl == 0) { 1171 IPSTAT_ADD(ips_fragtimeout, 1172 fpp->ipq_nfrags); 1173 ip_freef(&V_ipq[i], fpp); 1174 } 1175 } 1176 } 1177 /* 1178 * If we are over the maximum number of fragments 1179 * (due to the limit being lowered), drain off 1180 * enough to get down to the new limit. 1181 */ 1182 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) { 1183 for (i = 0; i < IPREASS_NHASH; i++) { 1184 while (V_nipq > V_maxnipq && 1185 !TAILQ_EMPTY(&V_ipq[i])) { 1186 IPSTAT_ADD(ips_fragdropped, 1187 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1188 ip_freef(&V_ipq[i], 1189 TAILQ_FIRST(&V_ipq[i])); 1190 } 1191 } 1192 } 1193 CURVNET_RESTORE(); 1194 } 1195 IPQ_UNLOCK(); 1196 VNET_LIST_RUNLOCK_NOSLEEP(); 1197 } 1198 1199 /* 1200 * Drain off all datagram fragments. 1201 */ 1202 static void 1203 ip_drain_locked(void) 1204 { 1205 int i; 1206 1207 IPQ_LOCK_ASSERT(); 1208 1209 for (i = 0; i < IPREASS_NHASH; i++) { 1210 while(!TAILQ_EMPTY(&V_ipq[i])) { 1211 IPSTAT_ADD(ips_fragdropped, 1212 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1213 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i])); 1214 } 1215 } 1216 } 1217 1218 void 1219 ip_drain(void) 1220 { 1221 VNET_ITERATOR_DECL(vnet_iter); 1222 1223 VNET_LIST_RLOCK_NOSLEEP(); 1224 IPQ_LOCK(); 1225 VNET_FOREACH(vnet_iter) { 1226 CURVNET_SET(vnet_iter); 1227 ip_drain_locked(); 1228 CURVNET_RESTORE(); 1229 } 1230 IPQ_UNLOCK(); 1231 VNET_LIST_RUNLOCK_NOSLEEP(); 1232 in_rtqdrain(); 1233 } 1234 1235 /* 1236 * The protocol to be inserted into ip_protox[] must be already registered 1237 * in inetsw[], either statically or through pf_proto_register(). 1238 */ 1239 int 1240 ipproto_register(short ipproto) 1241 { 1242 struct protosw *pr; 1243 1244 /* Sanity checks. */ 1245 if (ipproto <= 0 || ipproto >= IPPROTO_MAX) 1246 return (EPROTONOSUPPORT); 1247 1248 /* 1249 * The protocol slot must not be occupied by another protocol 1250 * already. An index pointing to IPPROTO_RAW is unused. 1251 */ 1252 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1253 if (pr == NULL) 1254 return (EPFNOSUPPORT); 1255 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1256 return (EEXIST); 1257 1258 /* Find the protocol position in inetsw[] and set the index. */ 1259 for (pr = inetdomain.dom_protosw; 1260 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1261 if (pr->pr_domain->dom_family == PF_INET && 1262 pr->pr_protocol && pr->pr_protocol == ipproto) { 1263 ip_protox[pr->pr_protocol] = pr - inetsw; 1264 return (0); 1265 } 1266 } 1267 return (EPROTONOSUPPORT); 1268 } 1269 1270 int 1271 ipproto_unregister(short ipproto) 1272 { 1273 struct protosw *pr; 1274 1275 /* Sanity checks. */ 1276 if (ipproto <= 0 || ipproto >= IPPROTO_MAX) 1277 return (EPROTONOSUPPORT); 1278 1279 /* Check if the protocol was indeed registered. */ 1280 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1281 if (pr == NULL) 1282 return (EPFNOSUPPORT); 1283 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1284 return (ENOENT); 1285 1286 /* Reset the protocol slot to IPPROTO_RAW. */ 1287 ip_protox[ipproto] = pr - inetsw; 1288 return (0); 1289 } 1290 1291 /* 1292 * Given address of next destination (final or next hop), return (referenced) 1293 * internet address info of interface to be used to get there. 1294 */ 1295 struct in_ifaddr * 1296 ip_rtaddr(struct in_addr dst, u_int fibnum) 1297 { 1298 struct route sro; 1299 struct sockaddr_in *sin; 1300 struct in_ifaddr *ia; 1301 1302 bzero(&sro, sizeof(sro)); 1303 sin = (struct sockaddr_in *)&sro.ro_dst; 1304 sin->sin_family = AF_INET; 1305 sin->sin_len = sizeof(*sin); 1306 sin->sin_addr = dst; 1307 in_rtalloc_ign(&sro, 0, fibnum); 1308 1309 if (sro.ro_rt == NULL) 1310 return (NULL); 1311 1312 ia = ifatoia(sro.ro_rt->rt_ifa); 1313 ifa_ref(&ia->ia_ifa); 1314 RTFREE(sro.ro_rt); 1315 return (ia); 1316 } 1317 1318 u_char inetctlerrmap[PRC_NCMDS] = { 1319 0, 0, 0, 0, 1320 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1321 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1322 EMSGSIZE, EHOSTUNREACH, 0, 0, 1323 0, 0, EHOSTUNREACH, 0, 1324 ENOPROTOOPT, ECONNREFUSED 1325 }; 1326 1327 /* 1328 * Forward a packet. If some error occurs return the sender 1329 * an icmp packet. Note we can't always generate a meaningful 1330 * icmp message because icmp doesn't have a large enough repertoire 1331 * of codes and types. 1332 * 1333 * If not forwarding, just drop the packet. This could be confusing 1334 * if ipforwarding was zero but some routing protocol was advancing 1335 * us as a gateway to somewhere. However, we must let the routing 1336 * protocol deal with that. 1337 * 1338 * The srcrt parameter indicates whether the packet is being forwarded 1339 * via a source route. 1340 */ 1341 void 1342 ip_forward(struct mbuf *m, int srcrt) 1343 { 1344 struct ip *ip = mtod(m, struct ip *); 1345 struct in_ifaddr *ia; 1346 struct mbuf *mcopy; 1347 struct sockaddr_in *sin; 1348 struct in_addr dest; 1349 struct route ro; 1350 int error, type = 0, code = 0, mtu = 0; 1351 1352 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1353 IPSTAT_INC(ips_cantforward); 1354 m_freem(m); 1355 return; 1356 } 1357 #ifdef IPSTEALTH 1358 if (!V_ipstealth) { 1359 #endif 1360 if (ip->ip_ttl <= IPTTLDEC) { 1361 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1362 0, 0); 1363 return; 1364 } 1365 #ifdef IPSTEALTH 1366 } 1367 #endif 1368 1369 bzero(&ro, sizeof(ro)); 1370 sin = (struct sockaddr_in *)&ro.ro_dst; 1371 sin->sin_family = AF_INET; 1372 sin->sin_len = sizeof(*sin); 1373 sin->sin_addr = ip->ip_dst; 1374 #ifdef RADIX_MPATH 1375 rtalloc_mpath_fib(&ro, 1376 ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr), 1377 M_GETFIB(m)); 1378 #else 1379 in_rtalloc_ign(&ro, 0, M_GETFIB(m)); 1380 #endif 1381 if (ro.ro_rt != NULL) { 1382 ia = ifatoia(ro.ro_rt->rt_ifa); 1383 ifa_ref(&ia->ia_ifa); 1384 } else 1385 ia = NULL; 1386 #ifndef IPSEC 1387 /* 1388 * 'ia' may be NULL if there is no route for this destination. 1389 * In case of IPsec, Don't discard it just yet, but pass it to 1390 * ip_output in case of outgoing IPsec policy. 1391 */ 1392 if (!srcrt && ia == NULL) { 1393 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1394 RO_RTFREE(&ro); 1395 return; 1396 } 1397 #endif 1398 1399 /* 1400 * Save the IP header and at most 8 bytes of the payload, 1401 * in case we need to generate an ICMP message to the src. 1402 * 1403 * XXX this can be optimized a lot by saving the data in a local 1404 * buffer on the stack (72 bytes at most), and only allocating the 1405 * mbuf if really necessary. The vast majority of the packets 1406 * are forwarded without having to send an ICMP back (either 1407 * because unnecessary, or because rate limited), so we are 1408 * really we are wasting a lot of work here. 1409 * 1410 * We don't use m_copy() because it might return a reference 1411 * to a shared cluster. Both this function and ip_output() 1412 * assume exclusive access to the IP header in `m', so any 1413 * data in a cluster may change before we reach icmp_error(). 1414 */ 1415 mcopy = m_gethdr(M_NOWAIT, m->m_type); 1416 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_NOWAIT)) { 1417 /* 1418 * It's probably ok if the pkthdr dup fails (because 1419 * the deep copy of the tag chain failed), but for now 1420 * be conservative and just discard the copy since 1421 * code below may some day want the tags. 1422 */ 1423 m_free(mcopy); 1424 mcopy = NULL; 1425 } 1426 if (mcopy != NULL) { 1427 mcopy->m_len = min(ntohs(ip->ip_len), M_TRAILINGSPACE(mcopy)); 1428 mcopy->m_pkthdr.len = mcopy->m_len; 1429 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1430 } 1431 1432 #ifdef IPSTEALTH 1433 if (!V_ipstealth) { 1434 #endif 1435 ip->ip_ttl -= IPTTLDEC; 1436 #ifdef IPSTEALTH 1437 } 1438 #endif 1439 1440 /* 1441 * If forwarding packet using same interface that it came in on, 1442 * perhaps should send a redirect to sender to shortcut a hop. 1443 * Only send redirect if source is sending directly to us, 1444 * and if packet was not source routed (or has any options). 1445 * Also, don't send redirect if forwarding using a default route 1446 * or a route modified by a redirect. 1447 */ 1448 dest.s_addr = 0; 1449 if (!srcrt && V_ipsendredirects && 1450 ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) { 1451 struct rtentry *rt; 1452 1453 rt = ro.ro_rt; 1454 1455 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1456 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1457 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1458 u_long src = ntohl(ip->ip_src.s_addr); 1459 1460 if (RTA(rt) && 1461 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1462 if (rt->rt_flags & RTF_GATEWAY) 1463 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1464 else 1465 dest.s_addr = ip->ip_dst.s_addr; 1466 /* Router requirements says to only send host redirects */ 1467 type = ICMP_REDIRECT; 1468 code = ICMP_REDIRECT_HOST; 1469 } 1470 } 1471 } 1472 1473 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL); 1474 1475 if (error == EMSGSIZE && ro.ro_rt) 1476 mtu = ro.ro_rt->rt_mtu; 1477 RO_RTFREE(&ro); 1478 1479 if (error) 1480 IPSTAT_INC(ips_cantforward); 1481 else { 1482 IPSTAT_INC(ips_forward); 1483 if (type) 1484 IPSTAT_INC(ips_redirectsent); 1485 else { 1486 if (mcopy) 1487 m_freem(mcopy); 1488 if (ia != NULL) 1489 ifa_free(&ia->ia_ifa); 1490 return; 1491 } 1492 } 1493 if (mcopy == NULL) { 1494 if (ia != NULL) 1495 ifa_free(&ia->ia_ifa); 1496 return; 1497 } 1498 1499 switch (error) { 1500 1501 case 0: /* forwarded, but need redirect */ 1502 /* type, code set above */ 1503 break; 1504 1505 case ENETUNREACH: 1506 case EHOSTUNREACH: 1507 case ENETDOWN: 1508 case EHOSTDOWN: 1509 default: 1510 type = ICMP_UNREACH; 1511 code = ICMP_UNREACH_HOST; 1512 break; 1513 1514 case EMSGSIZE: 1515 type = ICMP_UNREACH; 1516 code = ICMP_UNREACH_NEEDFRAG; 1517 1518 #ifdef IPSEC 1519 /* 1520 * If IPsec is configured for this path, 1521 * override any possibly mtu value set by ip_output. 1522 */ 1523 mtu = ip_ipsec_mtu(mcopy, mtu); 1524 #endif /* IPSEC */ 1525 /* 1526 * If the MTU was set before make sure we are below the 1527 * interface MTU. 1528 * If the MTU wasn't set before use the interface mtu or 1529 * fall back to the next smaller mtu step compared to the 1530 * current packet size. 1531 */ 1532 if (mtu != 0) { 1533 if (ia != NULL) 1534 mtu = min(mtu, ia->ia_ifp->if_mtu); 1535 } else { 1536 if (ia != NULL) 1537 mtu = ia->ia_ifp->if_mtu; 1538 else 1539 mtu = ip_next_mtu(ntohs(ip->ip_len), 0); 1540 } 1541 IPSTAT_INC(ips_cantfrag); 1542 break; 1543 1544 case ENOBUFS: 1545 /* 1546 * A router should not generate ICMP_SOURCEQUENCH as 1547 * required in RFC1812 Requirements for IP Version 4 Routers. 1548 * Source quench could be a big problem under DoS attacks, 1549 * or if the underlying interface is rate-limited. 1550 * Those who need source quench packets may re-enable them 1551 * via the net.inet.ip.sendsourcequench sysctl. 1552 */ 1553 if (V_ip_sendsourcequench == 0) { 1554 m_freem(mcopy); 1555 if (ia != NULL) 1556 ifa_free(&ia->ia_ifa); 1557 return; 1558 } else { 1559 type = ICMP_SOURCEQUENCH; 1560 code = 0; 1561 } 1562 break; 1563 1564 case EACCES: /* ipfw denied packet */ 1565 m_freem(mcopy); 1566 if (ia != NULL) 1567 ifa_free(&ia->ia_ifa); 1568 return; 1569 } 1570 if (ia != NULL) 1571 ifa_free(&ia->ia_ifa); 1572 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1573 } 1574 1575 void 1576 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1577 struct mbuf *m) 1578 { 1579 1580 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1581 struct bintime bt; 1582 1583 bintime(&bt); 1584 if (inp->inp_socket->so_options & SO_BINTIME) { 1585 *mp = sbcreatecontrol((caddr_t)&bt, sizeof(bt), 1586 SCM_BINTIME, SOL_SOCKET); 1587 if (*mp) 1588 mp = &(*mp)->m_next; 1589 } 1590 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1591 struct timeval tv; 1592 1593 bintime2timeval(&bt, &tv); 1594 *mp = sbcreatecontrol((caddr_t)&tv, sizeof(tv), 1595 SCM_TIMESTAMP, SOL_SOCKET); 1596 if (*mp) 1597 mp = &(*mp)->m_next; 1598 } 1599 } 1600 if (inp->inp_flags & INP_RECVDSTADDR) { 1601 *mp = sbcreatecontrol((caddr_t)&ip->ip_dst, 1602 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1603 if (*mp) 1604 mp = &(*mp)->m_next; 1605 } 1606 if (inp->inp_flags & INP_RECVTTL) { 1607 *mp = sbcreatecontrol((caddr_t)&ip->ip_ttl, 1608 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1609 if (*mp) 1610 mp = &(*mp)->m_next; 1611 } 1612 #ifdef notyet 1613 /* XXX 1614 * Moving these out of udp_input() made them even more broken 1615 * than they already were. 1616 */ 1617 /* options were tossed already */ 1618 if (inp->inp_flags & INP_RECVOPTS) { 1619 *mp = sbcreatecontrol((caddr_t)opts_deleted_above, 1620 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1621 if (*mp) 1622 mp = &(*mp)->m_next; 1623 } 1624 /* ip_srcroute doesn't do what we want here, need to fix */ 1625 if (inp->inp_flags & INP_RECVRETOPTS) { 1626 *mp = sbcreatecontrol((caddr_t)ip_srcroute(m), 1627 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1628 if (*mp) 1629 mp = &(*mp)->m_next; 1630 } 1631 #endif 1632 if (inp->inp_flags & INP_RECVIF) { 1633 struct ifnet *ifp; 1634 struct sdlbuf { 1635 struct sockaddr_dl sdl; 1636 u_char pad[32]; 1637 } sdlbuf; 1638 struct sockaddr_dl *sdp; 1639 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1640 1641 if ((ifp = m->m_pkthdr.rcvif) && 1642 ifp->if_index && ifp->if_index <= V_if_index) { 1643 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1644 /* 1645 * Change our mind and don't try copy. 1646 */ 1647 if (sdp->sdl_family != AF_LINK || 1648 sdp->sdl_len > sizeof(sdlbuf)) { 1649 goto makedummy; 1650 } 1651 bcopy(sdp, sdl2, sdp->sdl_len); 1652 } else { 1653 makedummy: 1654 sdl2->sdl_len = 1655 offsetof(struct sockaddr_dl, sdl_data[0]); 1656 sdl2->sdl_family = AF_LINK; 1657 sdl2->sdl_index = 0; 1658 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1659 } 1660 *mp = sbcreatecontrol((caddr_t)sdl2, sdl2->sdl_len, 1661 IP_RECVIF, IPPROTO_IP); 1662 if (*mp) 1663 mp = &(*mp)->m_next; 1664 } 1665 if (inp->inp_flags & INP_RECVTOS) { 1666 *mp = sbcreatecontrol((caddr_t)&ip->ip_tos, 1667 sizeof(u_char), IP_RECVTOS, IPPROTO_IP); 1668 if (*mp) 1669 mp = &(*mp)->m_next; 1670 } 1671 } 1672 1673 /* 1674 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the 1675 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on 1676 * locking. This code remains in ip_input.c as ip_mroute.c is optionally 1677 * compiled. 1678 */ 1679 static VNET_DEFINE(int, ip_rsvp_on); 1680 VNET_DEFINE(struct socket *, ip_rsvpd); 1681 1682 #define V_ip_rsvp_on VNET(ip_rsvp_on) 1683 1684 int 1685 ip_rsvp_init(struct socket *so) 1686 { 1687 1688 if (so->so_type != SOCK_RAW || 1689 so->so_proto->pr_protocol != IPPROTO_RSVP) 1690 return EOPNOTSUPP; 1691 1692 if (V_ip_rsvpd != NULL) 1693 return EADDRINUSE; 1694 1695 V_ip_rsvpd = so; 1696 /* 1697 * This may seem silly, but we need to be sure we don't over-increment 1698 * the RSVP counter, in case something slips up. 1699 */ 1700 if (!V_ip_rsvp_on) { 1701 V_ip_rsvp_on = 1; 1702 V_rsvp_on++; 1703 } 1704 1705 return 0; 1706 } 1707 1708 int 1709 ip_rsvp_done(void) 1710 { 1711 1712 V_ip_rsvpd = NULL; 1713 /* 1714 * This may seem silly, but we need to be sure we don't over-decrement 1715 * the RSVP counter, in case something slips up. 1716 */ 1717 if (V_ip_rsvp_on) { 1718 V_ip_rsvp_on = 0; 1719 V_rsvp_on--; 1720 } 1721 return 0; 1722 } 1723 1724 void 1725 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1726 { 1727 1728 if (rsvp_input_p) { /* call the real one if loaded */ 1729 rsvp_input_p(m, off); 1730 return; 1731 } 1732 1733 /* Can still get packets with rsvp_on = 0 if there is a local member 1734 * of the group to which the RSVP packet is addressed. But in this 1735 * case we want to throw the packet away. 1736 */ 1737 1738 if (!V_rsvp_on) { 1739 m_freem(m); 1740 return; 1741 } 1742 1743 if (V_ip_rsvpd != NULL) { 1744 rip_input(m, off); 1745 return; 1746 } 1747 /* Drop the packet */ 1748 m_freem(m); 1749 }
Cache object: 9aaa97dd81d55e983609d06c9b9c565a
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