ip_input.c revision 167886
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 * $FreeBSD: head/sys/netinet/ip_input.c 167886 2007-03-25 21:49:50Z rwatson $ 31 */ 32 33#include "opt_bootp.h" 34#include "opt_ipfw.h" 35#include "opt_ipstealth.h" 36#include "opt_ipsec.h" 37#include "opt_mac.h" 38#include "opt_carp.h" 39 40#include <sys/param.h> 41#include <sys/systm.h> 42#include <sys/callout.h> 43#include <sys/mbuf.h> 44#include <sys/malloc.h> 45#include <sys/domain.h> 46#include <sys/protosw.h> 47#include <sys/socket.h> 48#include <sys/time.h> 49#include <sys/kernel.h> 50#include <sys/syslog.h> 51#include <sys/sysctl.h> 52 53#include <net/pfil.h> 54#include <net/if.h> 55#include <net/if_types.h> 56#include <net/if_var.h> 57#include <net/if_dl.h> 58#include <net/route.h> 59#include <net/netisr.h> 60 61#include <netinet/in.h> 62#include <netinet/in_systm.h> 63#include <netinet/in_var.h> 64#include <netinet/ip.h> 65#include <netinet/in_pcb.h> 66#include <netinet/ip_var.h> 67#include <netinet/ip_icmp.h> 68#include <netinet/ip_options.h> 69#include <machine/in_cksum.h> 70#ifdef DEV_CARP 71#include <netinet/ip_carp.h> 72#endif 73#if defined(IPSEC) || defined(FAST_IPSEC) 74#include <netinet/ip_ipsec.h> 75#endif /* IPSEC */ 76 77#include <sys/socketvar.h> 78 79/* XXX: Temporary until ipfw_ether and ipfw_bridge are converted. */ 80#include <netinet/ip_fw.h> 81#include <netinet/ip_dummynet.h> 82 83#include <security/mac/mac_framework.h> 84 85int rsvp_on = 0; 86 87int ipforwarding = 0; 88SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 89 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 90 91static int ipsendredirects = 1; /* XXX */ 92SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 93 &ipsendredirects, 0, "Enable sending IP redirects"); 94 95int ip_defttl = IPDEFTTL; 96SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 97 &ip_defttl, 0, "Maximum TTL on IP packets"); 98 99static int ip_keepfaith = 0; 100SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 101 &ip_keepfaith, 0, 102 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 103 104static int ip_sendsourcequench = 0; 105SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 106 &ip_sendsourcequench, 0, 107 "Enable the transmission of source quench packets"); 108 109int ip_do_randomid = 0; 110SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 111 &ip_do_randomid, 0, 112 "Assign random ip_id values"); 113 114/* 115 * XXX - Setting ip_checkinterface mostly implements the receive side of 116 * the Strong ES model described in RFC 1122, but since the routing table 117 * and transmit implementation do not implement the Strong ES model, 118 * setting this to 1 results in an odd hybrid. 119 * 120 * XXX - ip_checkinterface currently must be disabled if you use ipnat 121 * to translate the destination address to another local interface. 122 * 123 * XXX - ip_checkinterface must be disabled if you add IP aliases 124 * to the loopback interface instead of the interface where the 125 * packets for those addresses are received. 126 */ 127static int ip_checkinterface = 0; 128SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 129 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 130 131struct pfil_head inet_pfil_hook; /* Packet filter hooks */ 132 133static struct ifqueue ipintrq; 134static int ipqmaxlen = IFQ_MAXLEN; 135 136extern struct domain inetdomain; 137extern struct protosw inetsw[]; 138u_char ip_protox[IPPROTO_MAX]; 139struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 140struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 141u_long in_ifaddrhmask; /* mask for hash table */ 142 143SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 144 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 145SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 146 &ipintrq.ifq_drops, 0, 147 "Number of packets dropped from the IP input queue"); 148 149struct ipstat ipstat; 150SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 151 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 152 153/* 154 * IP datagram reassembly. 155 */ 156#define IPREASS_NHASH_LOG2 6 157#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 158#define IPREASS_HMASK (IPREASS_NHASH - 1) 159#define IPREASS_HASH(x,y) \ 160 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 161 162static uma_zone_t ipq_zone; 163static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 164static struct mtx ipqlock; 165 166#define IPQ_LOCK() mtx_lock(&ipqlock) 167#define IPQ_UNLOCK() mtx_unlock(&ipqlock) 168#define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 169#define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 170 171static void maxnipq_update(void); 172static void ipq_zone_change(void *); 173 174static int maxnipq; /* Administrative limit on # reass queues. */ 175static int nipq = 0; /* Total # of reass queues */ 176SYSCTL_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, 177 &nipq, 0, "Current number of IPv4 fragment reassembly queue entries"); 178 179static int maxfragsperpacket; 180SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 181 &maxfragsperpacket, 0, 182 "Maximum number of IPv4 fragments allowed per packet"); 183 184struct callout ipport_tick_callout; 185 186#ifdef IPCTL_DEFMTU 187SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 188 &ip_mtu, 0, "Default MTU"); 189#endif 190 191#ifdef IPSTEALTH 192int ipstealth = 0; 193SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 194 &ipstealth, 0, "IP stealth mode, no TTL decrementation on forwarding"); 195#endif 196 197/* 198 * ipfw_ether and ipfw_bridge hooks. 199 * XXX: Temporary until those are converted to pfil_hooks as well. 200 */ 201ip_fw_chk_t *ip_fw_chk_ptr = NULL; 202ip_dn_io_t *ip_dn_io_ptr = NULL; 203int fw_one_pass = 1; 204 205static void ip_freef(struct ipqhead *, struct ipq *); 206 207/* 208 * IP initialization: fill in IP protocol switch table. 209 * All protocols not implemented in kernel go to raw IP protocol handler. 210 */ 211void 212ip_init() 213{ 214 register struct protosw *pr; 215 register int i; 216 217 TAILQ_INIT(&in_ifaddrhead); 218 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 219 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 220 if (pr == NULL) 221 panic("ip_init: PF_INET not found"); 222 223 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 224 for (i = 0; i < IPPROTO_MAX; i++) 225 ip_protox[i] = pr - inetsw; 226 /* 227 * Cycle through IP protocols and put them into the appropriate place 228 * in ip_protox[]. 229 */ 230 for (pr = inetdomain.dom_protosw; 231 pr < inetdomain.dom_protoswNPROTOSW; pr++) 232 if (pr->pr_domain->dom_family == PF_INET && 233 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 234 /* Be careful to only index valid IP protocols. */ 235 if (pr->pr_protocol < IPPROTO_MAX) 236 ip_protox[pr->pr_protocol] = pr - inetsw; 237 } 238 239 /* Initialize packet filter hooks. */ 240 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 241 inet_pfil_hook.ph_af = AF_INET; 242 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 243 printf("%s: WARNING: unable to register pfil hook, " 244 "error %d\n", __func__, i); 245 246 /* Initialize IP reassembly queue. */ 247 IPQ_LOCK_INIT(); 248 for (i = 0; i < IPREASS_NHASH; i++) 249 TAILQ_INIT(&ipq[i]); 250 maxnipq = nmbclusters / 32; 251 maxfragsperpacket = 16; 252 ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 253 NULL, UMA_ALIGN_PTR, 0); 254 maxnipq_update(); 255 256 /* Start ipport_tick. */ 257 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE); 258 ipport_tick(NULL); 259 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL, 260 SHUTDOWN_PRI_DEFAULT); 261 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, 262 NULL, EVENTHANDLER_PRI_ANY); 263 264 /* Initialize various other remaining things. */ 265 ip_id = time_second & 0xffff; 266 ipintrq.ifq_maxlen = ipqmaxlen; 267 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 268 netisr_register(NETISR_IP, ip_input, &ipintrq, NETISR_MPSAFE); 269} 270 271void ip_fini(xtp) 272 void *xtp; 273{ 274 callout_stop(&ipport_tick_callout); 275} 276 277/* 278 * Ip input routine. Checksum and byte swap header. If fragmented 279 * try to reassemble. Process options. Pass to next level. 280 */ 281void 282ip_input(struct mbuf *m) 283{ 284 struct ip *ip = NULL; 285 struct in_ifaddr *ia = NULL; 286 struct ifaddr *ifa; 287 int checkif, hlen = 0; 288 u_short sum; 289 int dchg = 0; /* dest changed after fw */ 290 struct in_addr odst; /* original dst address */ 291 292 M_ASSERTPKTHDR(m); 293 294 if (m->m_flags & M_FASTFWD_OURS) { 295 /* 296 * Firewall or NAT changed destination to local. 297 * We expect ip_len and ip_off to be in host byte order. 298 */ 299 m->m_flags &= ~M_FASTFWD_OURS; 300 /* Set up some basics that will be used later. */ 301 ip = mtod(m, struct ip *); 302 hlen = ip->ip_hl << 2; 303 goto ours; 304 } 305 306 ipstat.ips_total++; 307 308 if (m->m_pkthdr.len < sizeof(struct ip)) 309 goto tooshort; 310 311 if (m->m_len < sizeof (struct ip) && 312 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 313 ipstat.ips_toosmall++; 314 return; 315 } 316 ip = mtod(m, struct ip *); 317 318 if (ip->ip_v != IPVERSION) { 319 ipstat.ips_badvers++; 320 goto bad; 321 } 322 323 hlen = ip->ip_hl << 2; 324 if (hlen < sizeof(struct ip)) { /* minimum header length */ 325 ipstat.ips_badhlen++; 326 goto bad; 327 } 328 if (hlen > m->m_len) { 329 if ((m = m_pullup(m, hlen)) == NULL) { 330 ipstat.ips_badhlen++; 331 return; 332 } 333 ip = mtod(m, struct ip *); 334 } 335 336 /* 127/8 must not appear on wire - RFC1122 */ 337 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 338 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 339 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 340 ipstat.ips_badaddr++; 341 goto bad; 342 } 343 } 344 345 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 346 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 347 } else { 348 if (hlen == sizeof(struct ip)) { 349 sum = in_cksum_hdr(ip); 350 } else { 351 sum = in_cksum(m, hlen); 352 } 353 } 354 if (sum) { 355 ipstat.ips_badsum++; 356 goto bad; 357 } 358 359#ifdef ALTQ 360 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 361 /* packet is dropped by traffic conditioner */ 362 return; 363#endif 364 365 /* 366 * Convert fields to host representation. 367 */ 368 ip->ip_len = ntohs(ip->ip_len); 369 if (ip->ip_len < hlen) { 370 ipstat.ips_badlen++; 371 goto bad; 372 } 373 ip->ip_off = ntohs(ip->ip_off); 374 375 /* 376 * Check that the amount of data in the buffers 377 * is as at least much as the IP header would have us expect. 378 * Trim mbufs if longer than we expect. 379 * Drop packet if shorter than we expect. 380 */ 381 if (m->m_pkthdr.len < ip->ip_len) { 382tooshort: 383 ipstat.ips_tooshort++; 384 goto bad; 385 } 386 if (m->m_pkthdr.len > ip->ip_len) { 387 if (m->m_len == m->m_pkthdr.len) { 388 m->m_len = ip->ip_len; 389 m->m_pkthdr.len = ip->ip_len; 390 } else 391 m_adj(m, ip->ip_len - m->m_pkthdr.len); 392 } 393#if defined(IPSEC) || defined(FAST_IPSEC) 394 /* 395 * Bypass packet filtering for packets from a tunnel (gif). 396 */ 397 if (ip_ipsec_filtergif(m)) 398 goto passin; 399#endif /* IPSEC */ 400 401 /* 402 * Run through list of hooks for input packets. 403 * 404 * NB: Beware of the destination address changing (e.g. 405 * by NAT rewriting). When this happens, tell 406 * ip_forward to do the right thing. 407 */ 408 409 /* Jump over all PFIL processing if hooks are not active. */ 410 if (!PFIL_HOOKED(&inet_pfil_hook)) 411 goto passin; 412 413 odst = ip->ip_dst; 414 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 415 PFIL_IN, NULL) != 0) 416 return; 417 if (m == NULL) /* consumed by filter */ 418 return; 419 420 ip = mtod(m, struct ip *); 421 dchg = (odst.s_addr != ip->ip_dst.s_addr); 422 423#ifdef IPFIREWALL_FORWARD 424 if (m->m_flags & M_FASTFWD_OURS) { 425 m->m_flags &= ~M_FASTFWD_OURS; 426 goto ours; 427 } 428 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 429 /* 430 * Directly ship on the packet. This allows to forward packets 431 * that were destined for us to some other directly connected 432 * host. 433 */ 434 ip_forward(m, dchg); 435 return; 436 } 437#endif /* IPFIREWALL_FORWARD */ 438 439passin: 440 /* 441 * Process options and, if not destined for us, 442 * ship it on. ip_dooptions returns 1 when an 443 * error was detected (causing an icmp message 444 * to be sent and the original packet to be freed). 445 */ 446 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 447 return; 448 449 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 450 * matter if it is destined to another node, or whether it is 451 * a multicast one, RSVP wants it! and prevents it from being forwarded 452 * anywhere else. Also checks if the rsvp daemon is running before 453 * grabbing the packet. 454 */ 455 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 456 goto ours; 457 458 /* 459 * Check our list of addresses, to see if the packet is for us. 460 * If we don't have any addresses, assume any unicast packet 461 * we receive might be for us (and let the upper layers deal 462 * with it). 463 */ 464 if (TAILQ_EMPTY(&in_ifaddrhead) && 465 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 466 goto ours; 467 468 /* 469 * Enable a consistency check between the destination address 470 * and the arrival interface for a unicast packet (the RFC 1122 471 * strong ES model) if IP forwarding is disabled and the packet 472 * is not locally generated and the packet is not subject to 473 * 'ipfw fwd'. 474 * 475 * XXX - Checking also should be disabled if the destination 476 * address is ipnat'ed to a different interface. 477 * 478 * XXX - Checking is incompatible with IP aliases added 479 * to the loopback interface instead of the interface where 480 * the packets are received. 481 * 482 * XXX - This is the case for carp vhost IPs as well so we 483 * insert a workaround. If the packet got here, we already 484 * checked with carp_iamatch() and carp_forus(). 485 */ 486 checkif = ip_checkinterface && (ipforwarding == 0) && 487 m->m_pkthdr.rcvif != NULL && 488 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 489#ifdef DEV_CARP 490 !m->m_pkthdr.rcvif->if_carp && 491#endif 492 (dchg == 0); 493 494 /* 495 * Check for exact addresses in the hash bucket. 496 */ 497 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 498 /* 499 * If the address matches, verify that the packet 500 * arrived via the correct interface if checking is 501 * enabled. 502 */ 503 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 504 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 505 goto ours; 506 } 507 /* 508 * Check for broadcast addresses. 509 * 510 * Only accept broadcast packets that arrive via the matching 511 * interface. Reception of forwarded directed broadcasts would 512 * be handled via ip_forward() and ether_output() with the loopback 513 * into the stack for SIMPLEX interfaces handled by ether_output(). 514 */ 515 if (m->m_pkthdr.rcvif != NULL && 516 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 517 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 518 if (ifa->ifa_addr->sa_family != AF_INET) 519 continue; 520 ia = ifatoia(ifa); 521 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 522 ip->ip_dst.s_addr) 523 goto ours; 524 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 525 goto ours; 526#ifdef BOOTP_COMPAT 527 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 528 goto ours; 529#endif 530 } 531 } 532 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */ 533 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) { 534 ipstat.ips_cantforward++; 535 m_freem(m); 536 return; 537 } 538 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 539 struct in_multi *inm; 540 if (ip_mrouter) { 541 /* 542 * If we are acting as a multicast router, all 543 * incoming multicast packets are passed to the 544 * kernel-level multicast forwarding function. 545 * The packet is returned (relatively) intact; if 546 * ip_mforward() returns a non-zero value, the packet 547 * must be discarded, else it may be accepted below. 548 */ 549 if (ip_mforward && 550 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 551 ipstat.ips_cantforward++; 552 m_freem(m); 553 return; 554 } 555 556 /* 557 * The process-level routing daemon needs to receive 558 * all multicast IGMP packets, whether or not this 559 * host belongs to their destination groups. 560 */ 561 if (ip->ip_p == IPPROTO_IGMP) 562 goto ours; 563 ipstat.ips_forward++; 564 } 565 /* 566 * See if we belong to the destination multicast group on the 567 * arrival interface. 568 */ 569 IN_MULTI_LOCK(); 570 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 571 IN_MULTI_UNLOCK(); 572 if (inm == NULL) { 573 ipstat.ips_notmember++; 574 m_freem(m); 575 return; 576 } 577 goto ours; 578 } 579 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 580 goto ours; 581 if (ip->ip_dst.s_addr == INADDR_ANY) 582 goto ours; 583 584 /* 585 * FAITH(Firewall Aided Internet Translator) 586 */ 587 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 588 if (ip_keepfaith) { 589 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 590 goto ours; 591 } 592 m_freem(m); 593 return; 594 } 595 596 /* 597 * Not for us; forward if possible and desirable. 598 */ 599 if (ipforwarding == 0) { 600 ipstat.ips_cantforward++; 601 m_freem(m); 602 } else { 603#if defined(IPSEC) || defined(FAST_IPSEC) 604 if (ip_ipsec_fwd(m)) 605 goto bad; 606#endif /* IPSEC */ 607 ip_forward(m, dchg); 608 } 609 return; 610 611ours: 612#ifdef IPSTEALTH 613 /* 614 * IPSTEALTH: Process non-routing options only 615 * if the packet is destined for us. 616 */ 617 if (ipstealth && hlen > sizeof (struct ip) && 618 ip_dooptions(m, 1)) 619 return; 620#endif /* IPSTEALTH */ 621 622 /* Count the packet in the ip address stats */ 623 if (ia != NULL) { 624 ia->ia_ifa.if_ipackets++; 625 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 626 } 627 628 /* 629 * Attempt reassembly; if it succeeds, proceed. 630 * ip_reass() will return a different mbuf. 631 */ 632 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 633 m = ip_reass(m); 634 if (m == NULL) 635 return; 636 ip = mtod(m, struct ip *); 637 /* Get the header length of the reassembled packet */ 638 hlen = ip->ip_hl << 2; 639 } 640 641 /* 642 * Further protocols expect the packet length to be w/o the 643 * IP header. 644 */ 645 ip->ip_len -= hlen; 646 647#if defined(IPSEC) || defined(FAST_IPSEC) 648 /* 649 * enforce IPsec policy checking if we are seeing last header. 650 * note that we do not visit this with protocols with pcb layer 651 * code - like udp/tcp/raw ip. 652 */ 653 if (ip_ipsec_input(m)) 654 goto bad; 655#endif /* IPSEC */ 656 657 /* 658 * Switch out to protocol's input routine. 659 */ 660 ipstat.ips_delivered++; 661 662 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 663 return; 664bad: 665 m_freem(m); 666} 667 668/* 669 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 670 * max has slightly different semantics than the sysctl, for historical 671 * reasons. 672 */ 673static void 674maxnipq_update(void) 675{ 676 677 /* 678 * -1 for unlimited allocation. 679 */ 680 if (maxnipq < 0) 681 uma_zone_set_max(ipq_zone, 0); 682 /* 683 * Positive number for specific bound. 684 */ 685 if (maxnipq > 0) 686 uma_zone_set_max(ipq_zone, maxnipq); 687 /* 688 * Zero specifies no further fragment queue allocation -- set the 689 * bound very low, but rely on implementation elsewhere to actually 690 * prevent allocation and reclaim current queues. 691 */ 692 if (maxnipq == 0) 693 uma_zone_set_max(ipq_zone, 1); 694} 695 696static void 697ipq_zone_change(void *tag) 698{ 699 700 if (maxnipq > 0 && maxnipq < (nmbclusters / 32)) { 701 maxnipq = nmbclusters / 32; 702 maxnipq_update(); 703 } 704} 705 706static int 707sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 708{ 709 int error, i; 710 711 i = maxnipq; 712 error = sysctl_handle_int(oidp, &i, 0, req); 713 if (error || !req->newptr) 714 return (error); 715 716 /* 717 * XXXRW: Might be a good idea to sanity check the argument and place 718 * an extreme upper bound. 719 */ 720 if (i < -1) 721 return (EINVAL); 722 maxnipq = i; 723 maxnipq_update(); 724 return (0); 725} 726 727SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 728 NULL, 0, sysctl_maxnipq, "I", 729 "Maximum number of IPv4 fragment reassembly queue entries"); 730 731/* 732 * Take incoming datagram fragment and try to reassemble it into 733 * whole datagram. If the argument is the first fragment or one 734 * in between the function will return NULL and store the mbuf 735 * in the fragment chain. If the argument is the last fragment 736 * the packet will be reassembled and the pointer to the new 737 * mbuf returned for further processing. Only m_tags attached 738 * to the first packet/fragment are preserved. 739 * The IP header is *NOT* adjusted out of iplen. 740 */ 741 742struct mbuf * 743ip_reass(struct mbuf *m) 744{ 745 struct ip *ip; 746 struct mbuf *p, *q, *nq, *t; 747 struct ipq *fp = NULL; 748 struct ipqhead *head; 749 int i, hlen, next; 750 u_int8_t ecn, ecn0; 751 u_short hash; 752 753 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 754 if (maxnipq == 0 || maxfragsperpacket == 0) { 755 ipstat.ips_fragments++; 756 ipstat.ips_fragdropped++; 757 m_freem(m); 758 return (NULL); 759 } 760 761 ip = mtod(m, struct ip *); 762 hlen = ip->ip_hl << 2; 763 764 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 765 head = &ipq[hash]; 766 IPQ_LOCK(); 767 768 /* 769 * Look for queue of fragments 770 * of this datagram. 771 */ 772 TAILQ_FOREACH(fp, head, ipq_list) 773 if (ip->ip_id == fp->ipq_id && 774 ip->ip_src.s_addr == fp->ipq_src.s_addr && 775 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 776#ifdef MAC 777 mac_fragment_match(m, fp) && 778#endif 779 ip->ip_p == fp->ipq_p) 780 goto found; 781 782 fp = NULL; 783 784 /* 785 * Attempt to trim the number of allocated fragment queues if it 786 * exceeds the administrative limit. 787 */ 788 if ((nipq > maxnipq) && (maxnipq > 0)) { 789 /* 790 * drop something from the tail of the current queue 791 * before proceeding further 792 */ 793 struct ipq *q = TAILQ_LAST(head, ipqhead); 794 if (q == NULL) { /* gak */ 795 for (i = 0; i < IPREASS_NHASH; i++) { 796 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 797 if (r) { 798 ipstat.ips_fragtimeout += r->ipq_nfrags; 799 ip_freef(&ipq[i], r); 800 break; 801 } 802 } 803 } else { 804 ipstat.ips_fragtimeout += q->ipq_nfrags; 805 ip_freef(head, q); 806 } 807 } 808 809found: 810 /* 811 * Adjust ip_len to not reflect header, 812 * convert offset of this to bytes. 813 */ 814 ip->ip_len -= hlen; 815 if (ip->ip_off & IP_MF) { 816 /* 817 * Make sure that fragments have a data length 818 * that's a non-zero multiple of 8 bytes. 819 */ 820 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 821 ipstat.ips_toosmall++; /* XXX */ 822 goto dropfrag; 823 } 824 m->m_flags |= M_FRAG; 825 } else 826 m->m_flags &= ~M_FRAG; 827 ip->ip_off <<= 3; 828 829 830 /* 831 * Attempt reassembly; if it succeeds, proceed. 832 * ip_reass() will return a different mbuf. 833 */ 834 ipstat.ips_fragments++; 835 m->m_pkthdr.header = ip; 836 837 /* Previous ip_reass() started here. */ 838 /* 839 * Presence of header sizes in mbufs 840 * would confuse code below. 841 */ 842 m->m_data += hlen; 843 m->m_len -= hlen; 844 845 /* 846 * If first fragment to arrive, create a reassembly queue. 847 */ 848 if (fp == NULL) { 849 fp = uma_zalloc(ipq_zone, M_NOWAIT); 850 if (fp == NULL) 851 goto dropfrag; 852#ifdef MAC 853 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 854 uma_zfree(ipq_zone, fp); 855 fp = NULL; 856 goto dropfrag; 857 } 858 mac_create_ipq(m, fp); 859#endif 860 TAILQ_INSERT_HEAD(head, fp, ipq_list); 861 nipq++; 862 fp->ipq_nfrags = 1; 863 fp->ipq_ttl = IPFRAGTTL; 864 fp->ipq_p = ip->ip_p; 865 fp->ipq_id = ip->ip_id; 866 fp->ipq_src = ip->ip_src; 867 fp->ipq_dst = ip->ip_dst; 868 fp->ipq_frags = m; 869 m->m_nextpkt = NULL; 870 goto done; 871 } else { 872 fp->ipq_nfrags++; 873#ifdef MAC 874 mac_update_ipq(m, fp); 875#endif 876 } 877 878#define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 879 880 /* 881 * Handle ECN by comparing this segment with the first one; 882 * if CE is set, do not lose CE. 883 * drop if CE and not-ECT are mixed for the same packet. 884 */ 885 ecn = ip->ip_tos & IPTOS_ECN_MASK; 886 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 887 if (ecn == IPTOS_ECN_CE) { 888 if (ecn0 == IPTOS_ECN_NOTECT) 889 goto dropfrag; 890 if (ecn0 != IPTOS_ECN_CE) 891 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 892 } 893 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 894 goto dropfrag; 895 896 /* 897 * Find a segment which begins after this one does. 898 */ 899 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 900 if (GETIP(q)->ip_off > ip->ip_off) 901 break; 902 903 /* 904 * If there is a preceding segment, it may provide some of 905 * our data already. If so, drop the data from the incoming 906 * segment. If it provides all of our data, drop us, otherwise 907 * stick new segment in the proper place. 908 * 909 * If some of the data is dropped from the the preceding 910 * segment, then it's checksum is invalidated. 911 */ 912 if (p) { 913 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 914 if (i > 0) { 915 if (i >= ip->ip_len) 916 goto dropfrag; 917 m_adj(m, i); 918 m->m_pkthdr.csum_flags = 0; 919 ip->ip_off += i; 920 ip->ip_len -= i; 921 } 922 m->m_nextpkt = p->m_nextpkt; 923 p->m_nextpkt = m; 924 } else { 925 m->m_nextpkt = fp->ipq_frags; 926 fp->ipq_frags = m; 927 } 928 929 /* 930 * While we overlap succeeding segments trim them or, 931 * if they are completely covered, dequeue them. 932 */ 933 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 934 q = nq) { 935 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 936 if (i < GETIP(q)->ip_len) { 937 GETIP(q)->ip_len -= i; 938 GETIP(q)->ip_off += i; 939 m_adj(q, i); 940 q->m_pkthdr.csum_flags = 0; 941 break; 942 } 943 nq = q->m_nextpkt; 944 m->m_nextpkt = nq; 945 ipstat.ips_fragdropped++; 946 fp->ipq_nfrags--; 947 m_freem(q); 948 } 949 950 /* 951 * Check for complete reassembly and perform frag per packet 952 * limiting. 953 * 954 * Frag limiting is performed here so that the nth frag has 955 * a chance to complete the packet before we drop the packet. 956 * As a result, n+1 frags are actually allowed per packet, but 957 * only n will ever be stored. (n = maxfragsperpacket.) 958 * 959 */ 960 next = 0; 961 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 962 if (GETIP(q)->ip_off != next) { 963 if (fp->ipq_nfrags > maxfragsperpacket) { 964 ipstat.ips_fragdropped += fp->ipq_nfrags; 965 ip_freef(head, fp); 966 } 967 goto done; 968 } 969 next += GETIP(q)->ip_len; 970 } 971 /* Make sure the last packet didn't have the IP_MF flag */ 972 if (p->m_flags & M_FRAG) { 973 if (fp->ipq_nfrags > maxfragsperpacket) { 974 ipstat.ips_fragdropped += fp->ipq_nfrags; 975 ip_freef(head, fp); 976 } 977 goto done; 978 } 979 980 /* 981 * Reassembly is complete. Make sure the packet is a sane size. 982 */ 983 q = fp->ipq_frags; 984 ip = GETIP(q); 985 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 986 ipstat.ips_toolong++; 987 ipstat.ips_fragdropped += fp->ipq_nfrags; 988 ip_freef(head, fp); 989 goto done; 990 } 991 992 /* 993 * Concatenate fragments. 994 */ 995 m = q; 996 t = m->m_next; 997 m->m_next = NULL; 998 m_cat(m, t); 999 nq = q->m_nextpkt; 1000 q->m_nextpkt = NULL; 1001 for (q = nq; q != NULL; q = nq) { 1002 nq = q->m_nextpkt; 1003 q->m_nextpkt = NULL; 1004 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1005 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1006 m_cat(m, q); 1007 } 1008 /* 1009 * In order to do checksumming faster we do 'end-around carry' here 1010 * (and not in for{} loop), though it implies we are not going to 1011 * reassemble more than 64k fragments. 1012 */ 1013 m->m_pkthdr.csum_data = 1014 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1015#ifdef MAC 1016 mac_create_datagram_from_ipq(fp, m); 1017 mac_destroy_ipq(fp); 1018#endif 1019 1020 /* 1021 * Create header for new ip packet by modifying header of first 1022 * packet; dequeue and discard fragment reassembly header. 1023 * Make header visible. 1024 */ 1025 ip->ip_len = (ip->ip_hl << 2) + next; 1026 ip->ip_src = fp->ipq_src; 1027 ip->ip_dst = fp->ipq_dst; 1028 TAILQ_REMOVE(head, fp, ipq_list); 1029 nipq--; 1030 uma_zfree(ipq_zone, fp); 1031 m->m_len += (ip->ip_hl << 2); 1032 m->m_data -= (ip->ip_hl << 2); 1033 /* some debugging cruft by sklower, below, will go away soon */ 1034 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1035 m_fixhdr(m); 1036 ipstat.ips_reassembled++; 1037 IPQ_UNLOCK(); 1038 return (m); 1039 1040dropfrag: 1041 ipstat.ips_fragdropped++; 1042 if (fp != NULL) 1043 fp->ipq_nfrags--; 1044 m_freem(m); 1045done: 1046 IPQ_UNLOCK(); 1047 return (NULL); 1048 1049#undef GETIP 1050} 1051 1052/* 1053 * Free a fragment reassembly header and all 1054 * associated datagrams. 1055 */ 1056static void 1057ip_freef(fhp, fp) 1058 struct ipqhead *fhp; 1059 struct ipq *fp; 1060{ 1061 register struct mbuf *q; 1062 1063 IPQ_LOCK_ASSERT(); 1064 1065 while (fp->ipq_frags) { 1066 q = fp->ipq_frags; 1067 fp->ipq_frags = q->m_nextpkt; 1068 m_freem(q); 1069 } 1070 TAILQ_REMOVE(fhp, fp, ipq_list); 1071 uma_zfree(ipq_zone, fp); 1072 nipq--; 1073} 1074 1075/* 1076 * IP timer processing; 1077 * if a timer expires on a reassembly 1078 * queue, discard it. 1079 */ 1080void 1081ip_slowtimo() 1082{ 1083 register struct ipq *fp; 1084 int i; 1085 1086 IPQ_LOCK(); 1087 for (i = 0; i < IPREASS_NHASH; i++) { 1088 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1089 struct ipq *fpp; 1090 1091 fpp = fp; 1092 fp = TAILQ_NEXT(fp, ipq_list); 1093 if(--fpp->ipq_ttl == 0) { 1094 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1095 ip_freef(&ipq[i], fpp); 1096 } 1097 } 1098 } 1099 /* 1100 * If we are over the maximum number of fragments 1101 * (due to the limit being lowered), drain off 1102 * enough to get down to the new limit. 1103 */ 1104 if (maxnipq >= 0 && nipq > maxnipq) { 1105 for (i = 0; i < IPREASS_NHASH; i++) { 1106 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1107 ipstat.ips_fragdropped += 1108 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1109 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1110 } 1111 } 1112 } 1113 IPQ_UNLOCK(); 1114} 1115 1116/* 1117 * Drain off all datagram fragments. 1118 */ 1119void 1120ip_drain() 1121{ 1122 int i; 1123 1124 IPQ_LOCK(); 1125 for (i = 0; i < IPREASS_NHASH; i++) { 1126 while(!TAILQ_EMPTY(&ipq[i])) { 1127 ipstat.ips_fragdropped += 1128 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1129 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1130 } 1131 } 1132 IPQ_UNLOCK(); 1133 in_rtqdrain(); 1134} 1135 1136/* 1137 * The protocol to be inserted into ip_protox[] must be already registered 1138 * in inetsw[], either statically or through pf_proto_register(). 1139 */ 1140int 1141ipproto_register(u_char ipproto) 1142{ 1143 struct protosw *pr; 1144 1145 /* Sanity checks. */ 1146 if (ipproto == 0) 1147 return (EPROTONOSUPPORT); 1148 1149 /* 1150 * The protocol slot must not be occupied by another protocol 1151 * already. An index pointing to IPPROTO_RAW is unused. 1152 */ 1153 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1154 if (pr == NULL) 1155 return (EPFNOSUPPORT); 1156 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1157 return (EEXIST); 1158 1159 /* Find the protocol position in inetsw[] and set the index. */ 1160 for (pr = inetdomain.dom_protosw; 1161 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1162 if (pr->pr_domain->dom_family == PF_INET && 1163 pr->pr_protocol && pr->pr_protocol == ipproto) { 1164 /* Be careful to only index valid IP protocols. */ 1165 if (pr->pr_protocol < IPPROTO_MAX) { 1166 ip_protox[pr->pr_protocol] = pr - inetsw; 1167 return (0); 1168 } else 1169 return (EINVAL); 1170 } 1171 } 1172 return (EPROTONOSUPPORT); 1173} 1174 1175int 1176ipproto_unregister(u_char ipproto) 1177{ 1178 struct protosw *pr; 1179 1180 /* Sanity checks. */ 1181 if (ipproto == 0) 1182 return (EPROTONOSUPPORT); 1183 1184 /* Check if the protocol was indeed registered. */ 1185 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1186 if (pr == NULL) 1187 return (EPFNOSUPPORT); 1188 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1189 return (ENOENT); 1190 1191 /* Reset the protocol slot to IPPROTO_RAW. */ 1192 ip_protox[ipproto] = pr - inetsw; 1193 return (0); 1194} 1195 1196/* 1197 * Given address of next destination (final or next hop), 1198 * return internet address info of interface to be used to get there. 1199 */ 1200struct in_ifaddr * 1201ip_rtaddr(dst) 1202 struct in_addr dst; 1203{ 1204 struct route sro; 1205 struct sockaddr_in *sin; 1206 struct in_ifaddr *ifa; 1207 1208 bzero(&sro, sizeof(sro)); 1209 sin = (struct sockaddr_in *)&sro.ro_dst; 1210 sin->sin_family = AF_INET; 1211 sin->sin_len = sizeof(*sin); 1212 sin->sin_addr = dst; 1213 rtalloc_ign(&sro, RTF_CLONING); 1214 1215 if (sro.ro_rt == NULL) 1216 return (NULL); 1217 1218 ifa = ifatoia(sro.ro_rt->rt_ifa); 1219 RTFREE(sro.ro_rt); 1220 return (ifa); 1221} 1222 1223u_char inetctlerrmap[PRC_NCMDS] = { 1224 0, 0, 0, 0, 1225 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1226 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1227 EMSGSIZE, EHOSTUNREACH, 0, 0, 1228 0, 0, EHOSTUNREACH, 0, 1229 ENOPROTOOPT, ECONNREFUSED 1230}; 1231 1232/* 1233 * Forward a packet. If some error occurs return the sender 1234 * an icmp packet. Note we can't always generate a meaningful 1235 * icmp message because icmp doesn't have a large enough repertoire 1236 * of codes and types. 1237 * 1238 * If not forwarding, just drop the packet. This could be confusing 1239 * if ipforwarding was zero but some routing protocol was advancing 1240 * us as a gateway to somewhere. However, we must let the routing 1241 * protocol deal with that. 1242 * 1243 * The srcrt parameter indicates whether the packet is being forwarded 1244 * via a source route. 1245 */ 1246void 1247ip_forward(struct mbuf *m, int srcrt) 1248{ 1249 struct ip *ip = mtod(m, struct ip *); 1250 struct in_ifaddr *ia = NULL; 1251 struct mbuf *mcopy; 1252 struct in_addr dest; 1253 int error, type = 0, code = 0, mtu = 0; 1254 1255 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1256 ipstat.ips_cantforward++; 1257 m_freem(m); 1258 return; 1259 } 1260#ifdef IPSTEALTH 1261 if (!ipstealth) { 1262#endif 1263 if (ip->ip_ttl <= IPTTLDEC) { 1264 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1265 0, 0); 1266 return; 1267 } 1268#ifdef IPSTEALTH 1269 } 1270#endif 1271 1272 if (!srcrt && (ia = ip_rtaddr(ip->ip_dst)) == NULL) { 1273 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1274 return; 1275 } 1276 1277 /* 1278 * Save the IP header and at most 8 bytes of the payload, 1279 * in case we need to generate an ICMP message to the src. 1280 * 1281 * XXX this can be optimized a lot by saving the data in a local 1282 * buffer on the stack (72 bytes at most), and only allocating the 1283 * mbuf if really necessary. The vast majority of the packets 1284 * are forwarded without having to send an ICMP back (either 1285 * because unnecessary, or because rate limited), so we are 1286 * really we are wasting a lot of work here. 1287 * 1288 * We don't use m_copy() because it might return a reference 1289 * to a shared cluster. Both this function and ip_output() 1290 * assume exclusive access to the IP header in `m', so any 1291 * data in a cluster may change before we reach icmp_error(). 1292 */ 1293 MGETHDR(mcopy, M_DONTWAIT, m->m_type); 1294 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1295 /* 1296 * It's probably ok if the pkthdr dup fails (because 1297 * the deep copy of the tag chain failed), but for now 1298 * be conservative and just discard the copy since 1299 * code below may some day want the tags. 1300 */ 1301 m_free(mcopy); 1302 mcopy = NULL; 1303 } 1304 if (mcopy != NULL) { 1305 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy)); 1306 mcopy->m_pkthdr.len = mcopy->m_len; 1307 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1308 } 1309 1310#ifdef IPSTEALTH 1311 if (!ipstealth) { 1312#endif 1313 ip->ip_ttl -= IPTTLDEC; 1314#ifdef IPSTEALTH 1315 } 1316#endif 1317 1318 /* 1319 * If forwarding packet using same interface that it came in on, 1320 * perhaps should send a redirect to sender to shortcut a hop. 1321 * Only send redirect if source is sending directly to us, 1322 * and if packet was not source routed (or has any options). 1323 * Also, don't send redirect if forwarding using a default route 1324 * or a route modified by a redirect. 1325 */ 1326 dest.s_addr = 0; 1327 if (!srcrt && ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1328 struct sockaddr_in *sin; 1329 struct route ro; 1330 struct rtentry *rt; 1331 1332 bzero(&ro, sizeof(ro)); 1333 sin = (struct sockaddr_in *)&ro.ro_dst; 1334 sin->sin_family = AF_INET; 1335 sin->sin_len = sizeof(*sin); 1336 sin->sin_addr = ip->ip_dst; 1337 rtalloc_ign(&ro, RTF_CLONING); 1338 1339 rt = ro.ro_rt; 1340 1341 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1342 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1343#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1344 u_long src = ntohl(ip->ip_src.s_addr); 1345 1346 if (RTA(rt) && 1347 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1348 if (rt->rt_flags & RTF_GATEWAY) 1349 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1350 else 1351 dest.s_addr = ip->ip_dst.s_addr; 1352 /* Router requirements says to only send host redirects */ 1353 type = ICMP_REDIRECT; 1354 code = ICMP_REDIRECT_HOST; 1355 } 1356 } 1357 if (rt) 1358 RTFREE(rt); 1359 } 1360 1361 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 1362 if (error) 1363 ipstat.ips_cantforward++; 1364 else { 1365 ipstat.ips_forward++; 1366 if (type) 1367 ipstat.ips_redirectsent++; 1368 else { 1369 if (mcopy) 1370 m_freem(mcopy); 1371 return; 1372 } 1373 } 1374 if (mcopy == NULL) 1375 return; 1376 1377 switch (error) { 1378 1379 case 0: /* forwarded, but need redirect */ 1380 /* type, code set above */ 1381 break; 1382 1383 case ENETUNREACH: /* shouldn't happen, checked above */ 1384 case EHOSTUNREACH: 1385 case ENETDOWN: 1386 case EHOSTDOWN: 1387 default: 1388 type = ICMP_UNREACH; 1389 code = ICMP_UNREACH_HOST; 1390 break; 1391 1392 case EMSGSIZE: 1393 type = ICMP_UNREACH; 1394 code = ICMP_UNREACH_NEEDFRAG; 1395 1396#if defined(IPSEC) || defined(FAST_IPSEC) 1397 mtu = ip_ipsec_mtu(m); 1398#endif /* IPSEC */ 1399 /* 1400 * If the MTU wasn't set before use the interface mtu or 1401 * fall back to the next smaller mtu step compared to the 1402 * current packet size. 1403 */ 1404 if (mtu == 0) { 1405 if (ia != NULL) 1406 mtu = ia->ia_ifp->if_mtu; 1407 else 1408 mtu = ip_next_mtu(ip->ip_len, 0); 1409 } 1410 ipstat.ips_cantfrag++; 1411 break; 1412 1413 case ENOBUFS: 1414 /* 1415 * A router should not generate ICMP_SOURCEQUENCH as 1416 * required in RFC1812 Requirements for IP Version 4 Routers. 1417 * Source quench could be a big problem under DoS attacks, 1418 * or if the underlying interface is rate-limited. 1419 * Those who need source quench packets may re-enable them 1420 * via the net.inet.ip.sendsourcequench sysctl. 1421 */ 1422 if (ip_sendsourcequench == 0) { 1423 m_freem(mcopy); 1424 return; 1425 } else { 1426 type = ICMP_SOURCEQUENCH; 1427 code = 0; 1428 } 1429 break; 1430 1431 case EACCES: /* ipfw denied packet */ 1432 m_freem(mcopy); 1433 return; 1434 } 1435 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1436} 1437 1438void 1439ip_savecontrol(inp, mp, ip, m) 1440 register struct inpcb *inp; 1441 register struct mbuf **mp; 1442 register struct ip *ip; 1443 register struct mbuf *m; 1444{ 1445 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1446 struct bintime bt; 1447 1448 bintime(&bt); 1449 if (inp->inp_socket->so_options & SO_BINTIME) { 1450 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 1451 SCM_BINTIME, SOL_SOCKET); 1452 if (*mp) 1453 mp = &(*mp)->m_next; 1454 } 1455 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1456 struct timeval tv; 1457 1458 bintime2timeval(&bt, &tv); 1459 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1460 SCM_TIMESTAMP, SOL_SOCKET); 1461 if (*mp) 1462 mp = &(*mp)->m_next; 1463 } 1464 } 1465 if (inp->inp_flags & INP_RECVDSTADDR) { 1466 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1467 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1468 if (*mp) 1469 mp = &(*mp)->m_next; 1470 } 1471 if (inp->inp_flags & INP_RECVTTL) { 1472 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1473 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1474 if (*mp) 1475 mp = &(*mp)->m_next; 1476 } 1477#ifdef notyet 1478 /* XXX 1479 * Moving these out of udp_input() made them even more broken 1480 * than they already were. 1481 */ 1482 /* options were tossed already */ 1483 if (inp->inp_flags & INP_RECVOPTS) { 1484 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1485 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1486 if (*mp) 1487 mp = &(*mp)->m_next; 1488 } 1489 /* ip_srcroute doesn't do what we want here, need to fix */ 1490 if (inp->inp_flags & INP_RECVRETOPTS) { 1491 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1492 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1493 if (*mp) 1494 mp = &(*mp)->m_next; 1495 } 1496#endif 1497 if (inp->inp_flags & INP_RECVIF) { 1498 struct ifnet *ifp; 1499 struct sdlbuf { 1500 struct sockaddr_dl sdl; 1501 u_char pad[32]; 1502 } sdlbuf; 1503 struct sockaddr_dl *sdp; 1504 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1505 1506 if (((ifp = m->m_pkthdr.rcvif)) 1507 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1508 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1509 /* 1510 * Change our mind and don't try copy. 1511 */ 1512 if ((sdp->sdl_family != AF_LINK) 1513 || (sdp->sdl_len > sizeof(sdlbuf))) { 1514 goto makedummy; 1515 } 1516 bcopy(sdp, sdl2, sdp->sdl_len); 1517 } else { 1518makedummy: 1519 sdl2->sdl_len 1520 = offsetof(struct sockaddr_dl, sdl_data[0]); 1521 sdl2->sdl_family = AF_LINK; 1522 sdl2->sdl_index = 0; 1523 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1524 } 1525 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1526 IP_RECVIF, IPPROTO_IP); 1527 if (*mp) 1528 mp = &(*mp)->m_next; 1529 } 1530} 1531 1532/* 1533 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the 1534 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on 1535 * locking. This code remains in ip_input.c as ip_mroute.c is optionally 1536 * compiled. 1537 */ 1538static int ip_rsvp_on; 1539struct socket *ip_rsvpd; 1540int 1541ip_rsvp_init(struct socket *so) 1542{ 1543 if (so->so_type != SOCK_RAW || 1544 so->so_proto->pr_protocol != IPPROTO_RSVP) 1545 return EOPNOTSUPP; 1546 1547 if (ip_rsvpd != NULL) 1548 return EADDRINUSE; 1549 1550 ip_rsvpd = so; 1551 /* 1552 * This may seem silly, but we need to be sure we don't over-increment 1553 * the RSVP counter, in case something slips up. 1554 */ 1555 if (!ip_rsvp_on) { 1556 ip_rsvp_on = 1; 1557 rsvp_on++; 1558 } 1559 1560 return 0; 1561} 1562 1563int 1564ip_rsvp_done(void) 1565{ 1566 ip_rsvpd = NULL; 1567 /* 1568 * This may seem silly, but we need to be sure we don't over-decrement 1569 * the RSVP counter, in case something slips up. 1570 */ 1571 if (ip_rsvp_on) { 1572 ip_rsvp_on = 0; 1573 rsvp_on--; 1574 } 1575 return 0; 1576} 1577 1578void 1579rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1580{ 1581 if (rsvp_input_p) { /* call the real one if loaded */ 1582 rsvp_input_p(m, off); 1583 return; 1584 } 1585 1586 /* Can still get packets with rsvp_on = 0 if there is a local member 1587 * of the group to which the RSVP packet is addressed. But in this 1588 * case we want to throw the packet away. 1589 */ 1590 1591 if (!rsvp_on) { 1592 m_freem(m); 1593 return; 1594 } 1595 1596 if (ip_rsvpd != NULL) { 1597 rip_input(m, off); 1598 return; 1599 } 1600 /* Drop the packet */ 1601 m_freem(m); 1602} 1603