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 * $FreeBSD$ 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 #ifdef 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 85 int rsvp_on = 0; 86 87 int ipforwarding = 0; 88 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 89 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 90 91 static int ipsendredirects = 1; /* XXX */ 92 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 93 &ipsendredirects, 0, "Enable sending IP redirects"); 94 95 int ip_defttl = IPDEFTTL; 96 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 97 &ip_defttl, 0, "Maximum TTL on IP packets"); 98 99 static int ip_keepfaith = 0; 100 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 101 &ip_keepfaith, 0, 102 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 103 104 static int ip_sendsourcequench = 0; 105 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 106 &ip_sendsourcequench, 0, 107 "Enable the transmission of source quench packets"); 108 109 int ip_do_randomid = 0; 110 SYSCTL_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 */ 127 static int ip_checkinterface = 0; 128 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 129 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 130 131 struct pfil_head inet_pfil_hook; /* Packet filter hooks */ 132 133 static struct ifqueue ipintrq; 134 static int ipqmaxlen = IFQ_MAXLEN; 135 136 extern struct domain inetdomain; 137 extern struct protosw inetsw[]; 138 u_char ip_protox[IPPROTO_MAX]; 139 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 140 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 141 u_long in_ifaddrhmask; /* mask for hash table */ 142 143 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 144 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 145 SYSCTL_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"); 148 149 struct ipstat ipstat; 150 SYSCTL_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) 161 162 static uma_zone_t ipq_zone; 163 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 164 static 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) 170 171 static void maxnipq_update(void); 172 static void ipq_zone_change(void *); 173 174 static int maxnipq; /* Administrative limit on # reass queues. */ 175 static int nipq = 0; /* Total # of reass queues */ 176 SYSCTL_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, 177 &nipq, 0, "Current number of IPv4 fragment reassembly queue entries"); 178 179 static int maxfragsperpacket; 180 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 181 &maxfragsperpacket, 0, 182 "Maximum number of IPv4 fragments allowed per packet"); 183 184 struct callout ipport_tick_callout; 185 186 #ifdef IPCTL_DEFMTU 187 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 188 &ip_mtu, 0, "Default MTU"); 189 #endif 190 191 #ifdef IPSTEALTH 192 int ipstealth = 0; 193 SYSCTL_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 */ 201 ip_fw_chk_t *ip_fw_chk_ptr = NULL; 202 ip_dn_io_t *ip_dn_io_ptr = NULL; 203 int fw_one_pass = 1; 204 205 static 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 */ 211 void 212 ip_init(void) 213 { 214 struct protosw *pr; 215 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 } 270 271 void 272 ip_fini(void *xtp) 273 { 274 275 callout_stop(&ipport_tick_callout); 276 } 277 278 /* 279 * Ip input routine. Checksum and byte swap header. If fragmented 280 * try to reassemble. Process options. Pass to next level. 281 */ 282 void 283 ip_input(struct mbuf *m) 284 { 285 struct ip *ip = NULL; 286 struct in_ifaddr *ia = NULL; 287 struct ifaddr *ifa; 288 int checkif, hlen = 0; 289 u_short sum; 290 int dchg = 0; /* dest changed after fw */ 291 struct in_addr odst; /* original dst address */ 292 293 M_ASSERTPKTHDR(m); 294 295 if (m->m_flags & M_FASTFWD_OURS) { 296 /* 297 * Firewall or NAT changed destination to local. 298 * We expect ip_len and ip_off to be in host byte order. 299 */ 300 m->m_flags &= ~M_FASTFWD_OURS; 301 /* Set up some basics that will be used later. */ 302 ip = mtod(m, struct ip *); 303 hlen = ip->ip_hl << 2; 304 goto ours; 305 } 306 307 ipstat.ips_total++; 308 309 if (m->m_pkthdr.len < sizeof(struct ip)) 310 goto tooshort; 311 312 if (m->m_len < sizeof (struct ip) && 313 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 314 ipstat.ips_toosmall++; 315 return; 316 } 317 ip = mtod(m, struct ip *); 318 319 if (ip->ip_v != IPVERSION) { 320 ipstat.ips_badvers++; 321 goto bad; 322 } 323 324 hlen = ip->ip_hl << 2; 325 if (hlen < sizeof(struct ip)) { /* minimum header length */ 326 ipstat.ips_badhlen++; 327 goto bad; 328 } 329 if (hlen > m->m_len) { 330 if ((m = m_pullup(m, hlen)) == NULL) { 331 ipstat.ips_badhlen++; 332 return; 333 } 334 ip = mtod(m, struct ip *); 335 } 336 337 /* 127/8 must not appear on wire - RFC1122 */ 338 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 339 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 340 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 341 ipstat.ips_badaddr++; 342 goto bad; 343 } 344 } 345 346 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 347 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 348 } else { 349 if (hlen == sizeof(struct ip)) { 350 sum = in_cksum_hdr(ip); 351 } else { 352 sum = in_cksum(m, hlen); 353 } 354 } 355 if (sum) { 356 ipstat.ips_badsum++; 357 goto bad; 358 } 359 360 #ifdef ALTQ 361 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 362 /* packet is dropped by traffic conditioner */ 363 return; 364 #endif 365 366 /* 367 * Convert fields to host representation. 368 */ 369 ip->ip_len = ntohs(ip->ip_len); 370 if (ip->ip_len < hlen) { 371 ipstat.ips_badlen++; 372 goto bad; 373 } 374 ip->ip_off = ntohs(ip->ip_off); 375 376 /* 377 * Check that the amount of data in the buffers 378 * is as at least much as the IP header would have us expect. 379 * Trim mbufs if longer than we expect. 380 * Drop packet if shorter than we expect. 381 */ 382 if (m->m_pkthdr.len < ip->ip_len) { 383 tooshort: 384 ipstat.ips_tooshort++; 385 goto bad; 386 } 387 if (m->m_pkthdr.len > ip->ip_len) { 388 if (m->m_len == m->m_pkthdr.len) { 389 m->m_len = ip->ip_len; 390 m->m_pkthdr.len = ip->ip_len; 391 } else 392 m_adj(m, ip->ip_len - m->m_pkthdr.len); 393 } 394 #ifdef IPSEC 395 /* 396 * Bypass packet filtering for packets from a tunnel (gif). 397 */ 398 if (ip_ipsec_filtertunnel(m)) 399 goto passin; 400 #endif /* IPSEC */ 401 402 /* 403 * Run through list of hooks for input packets. 404 * 405 * NB: Beware of the destination address changing (e.g. 406 * by NAT rewriting). When this happens, tell 407 * ip_forward to do the right thing. 408 */ 409 410 /* Jump over all PFIL processing if hooks are not active. */ 411 if (!PFIL_HOOKED(&inet_pfil_hook)) 412 goto passin; 413 414 odst = ip->ip_dst; 415 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 416 PFIL_IN, NULL) != 0) 417 return; 418 if (m == NULL) /* consumed by filter */ 419 return; 420 421 ip = mtod(m, struct ip *); 422 dchg = (odst.s_addr != ip->ip_dst.s_addr); 423 424 #ifdef IPFIREWALL_FORWARD 425 if (m->m_flags & M_FASTFWD_OURS) { 426 m->m_flags &= ~M_FASTFWD_OURS; 427 goto ours; 428 } 429 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 430 /* 431 * Directly ship on the packet. This allows to forward packets 432 * that were destined for us to some other directly connected 433 * host. 434 */ 435 ip_forward(m, dchg); 436 return; 437 } 438 #endif /* IPFIREWALL_FORWARD */ 439 440 passin: 441 /* 442 * Process options and, if not destined for us, 443 * ship it on. ip_dooptions returns 1 when an 444 * error was detected (causing an icmp message 445 * to be sent and the original packet to be freed). 446 */ 447 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 448 return; 449 450 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 451 * matter if it is destined to another node, or whether it is 452 * a multicast one, RSVP wants it! and prevents it from being forwarded 453 * anywhere else. Also checks if the rsvp daemon is running before 454 * grabbing the packet. 455 */ 456 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 457 goto ours; 458 459 /* 460 * Check our list of addresses, to see if the packet is for us. 461 * If we don't have any addresses, assume any unicast packet 462 * we receive might be for us (and let the upper layers deal 463 * with it). 464 */ 465 if (TAILQ_EMPTY(&in_ifaddrhead) && 466 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 467 goto ours; 468 469 /* 470 * Enable a consistency check between the destination address 471 * and the arrival interface for a unicast packet (the RFC 1122 472 * strong ES model) if IP forwarding is disabled and the packet 473 * is not locally generated and the packet is not subject to 474 * 'ipfw fwd'. 475 * 476 * XXX - Checking also should be disabled if the destination 477 * address is ipnat'ed to a different interface. 478 * 479 * XXX - Checking is incompatible with IP aliases added 480 * to the loopback interface instead of the interface where 481 * the packets are received. 482 * 483 * XXX - This is the case for carp vhost IPs as well so we 484 * insert a workaround. If the packet got here, we already 485 * checked with carp_iamatch() and carp_forus(). 486 */ 487 checkif = ip_checkinterface && (ipforwarding == 0) && 488 m->m_pkthdr.rcvif != NULL && 489 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 490 #ifdef DEV_CARP 491 !m->m_pkthdr.rcvif->if_carp && 492 #endif 493 (dchg == 0); 494 495 /* 496 * Check for exact addresses in the hash bucket. 497 */ 498 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 499 /* 500 * If the address matches, verify that the packet 501 * arrived via the correct interface if checking is 502 * enabled. 503 */ 504 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 505 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 506 goto ours; 507 } 508 /* 509 * Check for broadcast addresses. 510 * 511 * Only accept broadcast packets that arrive via the matching 512 * interface. Reception of forwarded directed broadcasts would 513 * be handled via ip_forward() and ether_output() with the loopback 514 * into the stack for SIMPLEX interfaces handled by ether_output(). 515 */ 516 if (m->m_pkthdr.rcvif != NULL && 517 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 518 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 519 if (ifa->ifa_addr->sa_family != AF_INET) 520 continue; 521 ia = ifatoia(ifa); 522 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 523 ip->ip_dst.s_addr) 524 goto ours; 525 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 526 goto ours; 527 #ifdef BOOTP_COMPAT 528 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 529 goto ours; 530 #endif 531 } 532 } 533 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */ 534 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) { 535 ipstat.ips_cantforward++; 536 m_freem(m); 537 return; 538 } 539 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 540 struct in_multi *inm; 541 if (ip_mrouter) { 542 /* 543 * If we are acting as a multicast router, all 544 * incoming multicast packets are passed to the 545 * kernel-level multicast forwarding function. 546 * The packet is returned (relatively) intact; if 547 * ip_mforward() returns a non-zero value, the packet 548 * must be discarded, else it may be accepted below. 549 */ 550 if (ip_mforward && 551 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 552 ipstat.ips_cantforward++; 553 m_freem(m); 554 return; 555 } 556 557 /* 558 * The process-level routing daemon needs to receive 559 * all multicast IGMP packets, whether or not this 560 * host belongs to their destination groups. 561 */ 562 if (ip->ip_p == IPPROTO_IGMP) 563 goto ours; 564 ipstat.ips_forward++; 565 } 566 /* 567 * See if we belong to the destination multicast group on the 568 * arrival interface. 569 */ 570 IN_MULTI_LOCK(); 571 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 572 IN_MULTI_UNLOCK(); 573 if (inm == NULL) { 574 ipstat.ips_notmember++; 575 m_freem(m); 576 return; 577 } 578 goto ours; 579 } 580 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 581 goto ours; 582 if (ip->ip_dst.s_addr == INADDR_ANY) 583 goto ours; 584 585 /* 586 * FAITH(Firewall Aided Internet Translator) 587 */ 588 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 589 if (ip_keepfaith) { 590 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 591 goto ours; 592 } 593 m_freem(m); 594 return; 595 } 596 597 /* 598 * Not for us; forward if possible and desirable. 599 */ 600 if (ipforwarding == 0) { 601 ipstat.ips_cantforward++; 602 m_freem(m); 603 } else { 604 #ifdef IPSEC 605 if (ip_ipsec_fwd(m)) 606 goto bad; 607 #endif /* IPSEC */ 608 ip_forward(m, dchg); 609 } 610 return; 611 612 ours: 613 #ifdef IPSTEALTH 614 /* 615 * IPSTEALTH: Process non-routing options only 616 * if the packet is destined for us. 617 */ 618 if (ipstealth && hlen > sizeof (struct ip) && 619 ip_dooptions(m, 1)) 620 return; 621 #endif /* IPSTEALTH */ 622 623 /* Count the packet in the ip address stats */ 624 if (ia != NULL) { 625 ia->ia_ifa.if_ipackets++; 626 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 627 } 628 629 /* 630 * Attempt reassembly; if it succeeds, proceed. 631 * ip_reass() will return a different mbuf. 632 */ 633 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 634 m = ip_reass(m); 635 if (m == NULL) 636 return; 637 ip = mtod(m, struct ip *); 638 /* Get the header length of the reassembled packet */ 639 hlen = ip->ip_hl << 2; 640 } 641 642 /* 643 * Further protocols expect the packet length to be w/o the 644 * IP header. 645 */ 646 ip->ip_len -= hlen; 647 648 #ifdef IPSEC 649 /* 650 * enforce IPsec policy checking if we are seeing last header. 651 * note that we do not visit this with protocols with pcb layer 652 * code - like udp/tcp/raw ip. 653 */ 654 if (ip_ipsec_input(m)) 655 goto bad; 656 #endif /* IPSEC */ 657 658 /* 659 * Switch out to protocol's input routine. 660 */ 661 ipstat.ips_delivered++; 662 663 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 664 return; 665 bad: 666 m_freem(m); 667 } 668 669 /* 670 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 671 * max has slightly different semantics than the sysctl, for historical 672 * reasons. 673 */ 674 static void 675 maxnipq_update(void) 676 { 677 678 /* 679 * -1 for unlimited allocation. 680 */ 681 if (maxnipq < 0) 682 uma_zone_set_max(ipq_zone, 0); 683 /* 684 * Positive number for specific bound. 685 */ 686 if (maxnipq > 0) 687 uma_zone_set_max(ipq_zone, maxnipq); 688 /* 689 * Zero specifies no further fragment queue allocation -- set the 690 * bound very low, but rely on implementation elsewhere to actually 691 * prevent allocation and reclaim current queues. 692 */ 693 if (maxnipq == 0) 694 uma_zone_set_max(ipq_zone, 1); 695 } 696 697 static void 698 ipq_zone_change(void *tag) 699 { 700 701 if (maxnipq > 0 && maxnipq < (nmbclusters / 32)) { 702 maxnipq = nmbclusters / 32; 703 maxnipq_update(); 704 } 705 } 706 707 static int 708 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 709 { 710 int error, i; 711 712 i = maxnipq; 713 error = sysctl_handle_int(oidp, &i, 0, req); 714 if (error || !req->newptr) 715 return (error); 716 717 /* 718 * XXXRW: Might be a good idea to sanity check the argument and place 719 * an extreme upper bound. 720 */ 721 if (i < -1) 722 return (EINVAL); 723 maxnipq = i; 724 maxnipq_update(); 725 return (0); 726 } 727 728 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 729 NULL, 0, sysctl_maxnipq, "I", 730 "Maximum number of IPv4 fragment reassembly queue entries"); 731 732 /* 733 * Take incoming datagram fragment and try to reassemble it into 734 * whole datagram. If the argument is the first fragment or one 735 * in between the function will return NULL and store the mbuf 736 * in the fragment chain. If the argument is the last fragment 737 * the packet will be reassembled and the pointer to the new 738 * mbuf returned for further processing. Only m_tags attached 739 * to the first packet/fragment are preserved. 740 * The IP header is *NOT* adjusted out of iplen. 741 */ 742 struct mbuf * 743 ip_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 } 808 809 found: 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 1040 dropfrag: 1041 ipstat.ips_fragdropped++; 1042 if (fp != NULL) 1043 fp->ipq_nfrags--; 1044 m_freem(m); 1045 done: 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 */ 1056 static void 1057 ip_freef(struct ipqhead *fhp, struct ipq *fp) 1058 { 1059 struct mbuf *q; 1060 1061 IPQ_LOCK_ASSERT(); 1062 1063 while (fp->ipq_frags) { 1064 q = fp->ipq_frags; 1065 fp->ipq_frags = q->m_nextpkt; 1066 m_freem(q); 1067 } 1068 TAILQ_REMOVE(fhp, fp, ipq_list); 1069 uma_zfree(ipq_zone, fp); 1070 nipq--; 1071 } 1072 1073 /* 1074 * IP timer processing; 1075 * if a timer expires on a reassembly 1076 * queue, discard it. 1077 */ 1078 void 1079 ip_slowtimo(void) 1080 { 1081 struct ipq *fp; 1082 int i; 1083 1084 IPQ_LOCK(); 1085 for (i = 0; i < IPREASS_NHASH; i++) { 1086 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1087 struct ipq *fpp; 1088 1089 fpp = fp; 1090 fp = TAILQ_NEXT(fp, ipq_list); 1091 if(--fpp->ipq_ttl == 0) { 1092 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1093 ip_freef(&ipq[i], fpp); 1094 } 1095 } 1096 } 1097 /* 1098 * If we are over the maximum number of fragments 1099 * (due to the limit being lowered), drain off 1100 * enough to get down to the new limit. 1101 */ 1102 if (maxnipq >= 0 && nipq > maxnipq) { 1103 for (i = 0; i < IPREASS_NHASH; i++) { 1104 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1105 ipstat.ips_fragdropped += 1106 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1107 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1108 } 1109 } 1110 } 1111 IPQ_UNLOCK(); 1112 } 1113 1114 /* 1115 * Drain off all datagram fragments. 1116 */ 1117 void 1118 ip_drain(void) 1119 { 1120 int i; 1121 1122 IPQ_LOCK(); 1123 for (i = 0; i < IPREASS_NHASH; i++) { 1124 while(!TAILQ_EMPTY(&ipq[i])) { 1125 ipstat.ips_fragdropped += 1126 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1127 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1128 } 1129 } 1130 IPQ_UNLOCK(); 1131 in_rtqdrain(); 1132 } 1133 1134 /* 1135 * The protocol to be inserted into ip_protox[] must be already registered 1136 * in inetsw[], either statically or through pf_proto_register(). 1137 */ 1138 int 1139 ipproto_register(u_char ipproto) 1140 { 1141 struct protosw *pr; 1142 1143 /* Sanity checks. */ 1144 if (ipproto == 0) 1145 return (EPROTONOSUPPORT); 1146 1147 /* 1148 * The protocol slot must not be occupied by another protocol 1149 * already. An index pointing to IPPROTO_RAW is unused. 1150 */ 1151 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1152 if (pr == NULL) 1153 return (EPFNOSUPPORT); 1154 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1155 return (EEXIST); 1156 1157 /* Find the protocol position in inetsw[] and set the index. */ 1158 for (pr = inetdomain.dom_protosw; 1159 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1160 if (pr->pr_domain->dom_family == PF_INET && 1161 pr->pr_protocol && pr->pr_protocol == ipproto) { 1162 /* Be careful to only index valid IP protocols. */ 1163 if (pr->pr_protocol < IPPROTO_MAX) { 1164 ip_protox[pr->pr_protocol] = pr - inetsw; 1165 return (0); 1166 } else 1167 return (EINVAL); 1168 } 1169 } 1170 return (EPROTONOSUPPORT); 1171 } 1172 1173 int 1174 ipproto_unregister(u_char ipproto) 1175 { 1176 struct protosw *pr; 1177 1178 /* Sanity checks. */ 1179 if (ipproto == 0) 1180 return (EPROTONOSUPPORT); 1181 1182 /* Check if the protocol was indeed registered. */ 1183 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1184 if (pr == NULL) 1185 return (EPFNOSUPPORT); 1186 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1187 return (ENOENT); 1188 1189 /* Reset the protocol slot to IPPROTO_RAW. */ 1190 ip_protox[ipproto] = pr - inetsw; 1191 return (0); 1192 } 1193 1194 /* 1195 * Given address of next destination (final or next hop), 1196 * return internet address info of interface to be used to get there. 1197 */ 1198 struct in_ifaddr * 1199 ip_rtaddr(struct in_addr dst) 1200 { 1201 struct route sro; 1202 struct sockaddr_in *sin; 1203 struct in_ifaddr *ifa; 1204 1205 bzero(&sro, sizeof(sro)); 1206 sin = (struct sockaddr_in *)&sro.ro_dst; 1207 sin->sin_family = AF_INET; 1208 sin->sin_len = sizeof(*sin); 1209 sin->sin_addr = dst; 1210 rtalloc_ign(&sro, RTF_CLONING); 1211 1212 if (sro.ro_rt == NULL) 1213 return (NULL); 1214 1215 ifa = ifatoia(sro.ro_rt->rt_ifa); 1216 RTFREE(sro.ro_rt); 1217 return (ifa); 1218 } 1219 1220 u_char inetctlerrmap[PRC_NCMDS] = { 1221 0, 0, 0, 0, 1222 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1223 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1224 EMSGSIZE, EHOSTUNREACH, 0, 0, 1225 0, 0, EHOSTUNREACH, 0, 1226 ENOPROTOOPT, ECONNREFUSED 1227 }; 1228 1229 /* 1230 * Forward a packet. If some error occurs return the sender 1231 * an icmp packet. Note we can't always generate a meaningful 1232 * icmp message because icmp doesn't have a large enough repertoire 1233 * of codes and types. 1234 * 1235 * If not forwarding, just drop the packet. This could be confusing 1236 * if ipforwarding was zero but some routing protocol was advancing 1237 * us as a gateway to somewhere. However, we must let the routing 1238 * protocol deal with that. 1239 * 1240 * The srcrt parameter indicates whether the packet is being forwarded 1241 * via a source route. 1242 */ 1243 void 1244 ip_forward(struct mbuf *m, int srcrt) 1245 { 1246 struct ip *ip = mtod(m, struct ip *); 1247 struct in_ifaddr *ia = NULL; 1248 struct mbuf *mcopy; 1249 struct in_addr dest; 1250 int error, type = 0, code = 0, mtu = 0; 1251 1252 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1253 ipstat.ips_cantforward++; 1254 m_freem(m); 1255 return; 1256 } 1257 #ifdef IPSTEALTH 1258 if (!ipstealth) { 1259 #endif 1260 if (ip->ip_ttl <= IPTTLDEC) { 1261 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1262 0, 0); 1263 return; 1264 } 1265 #ifdef IPSTEALTH 1266 } 1267 #endif 1268 1269 if (!srcrt && (ia = ip_rtaddr(ip->ip_dst)) == NULL) { 1270 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1271 return; 1272 } 1273 1274 /* 1275 * Save the IP header and at most 8 bytes of the payload, 1276 * in case we need to generate an ICMP message to the src. 1277 * 1278 * XXX this can be optimized a lot by saving the data in a local 1279 * buffer on the stack (72 bytes at most), and only allocating the 1280 * mbuf if really necessary. The vast majority of the packets 1281 * are forwarded without having to send an ICMP back (either 1282 * because unnecessary, or because rate limited), so we are 1283 * really we are wasting a lot of work here. 1284 * 1285 * We don't use m_copy() because it might return a reference 1286 * to a shared cluster. Both this function and ip_output() 1287 * assume exclusive access to the IP header in `m', so any 1288 * data in a cluster may change before we reach icmp_error(). 1289 */ 1290 MGETHDR(mcopy, M_DONTWAIT, m->m_type); 1291 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1292 /* 1293 * It's probably ok if the pkthdr dup fails (because 1294 * the deep copy of the tag chain failed), but for now 1295 * be conservative and just discard the copy since 1296 * code below may some day want the tags. 1297 */ 1298 m_free(mcopy); 1299 mcopy = NULL; 1300 } 1301 if (mcopy != NULL) { 1302 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy)); 1303 mcopy->m_pkthdr.len = mcopy->m_len; 1304 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1305 } 1306 1307 #ifdef IPSTEALTH 1308 if (!ipstealth) { 1309 #endif 1310 ip->ip_ttl -= IPTTLDEC; 1311 #ifdef IPSTEALTH 1312 } 1313 #endif 1314 1315 /* 1316 * If forwarding packet using same interface that it came in on, 1317 * perhaps should send a redirect to sender to shortcut a hop. 1318 * Only send redirect if source is sending directly to us, 1319 * and if packet was not source routed (or has any options). 1320 * Also, don't send redirect if forwarding using a default route 1321 * or a route modified by a redirect. 1322 */ 1323 dest.s_addr = 0; 1324 if (!srcrt && ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1325 struct sockaddr_in *sin; 1326 struct route ro; 1327 struct rtentry *rt; 1328 1329 bzero(&ro, sizeof(ro)); 1330 sin = (struct sockaddr_in *)&ro.ro_dst; 1331 sin->sin_family = AF_INET; 1332 sin->sin_len = sizeof(*sin); 1333 sin->sin_addr = ip->ip_dst; 1334 rtalloc_ign(&ro, RTF_CLONING); 1335 1336 rt = ro.ro_rt; 1337 1338 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1339 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1340 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1341 u_long src = ntohl(ip->ip_src.s_addr); 1342 1343 if (RTA(rt) && 1344 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1345 if (rt->rt_flags & RTF_GATEWAY) 1346 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1347 else 1348 dest.s_addr = ip->ip_dst.s_addr; 1349 /* Router requirements says to only send host redirects */ 1350 type = ICMP_REDIRECT; 1351 code = ICMP_REDIRECT_HOST; 1352 } 1353 } 1354 if (rt) 1355 RTFREE(rt); 1356 } 1357 1358 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 1359 if (error) 1360 ipstat.ips_cantforward++; 1361 else { 1362 ipstat.ips_forward++; 1363 if (type) 1364 ipstat.ips_redirectsent++; 1365 else { 1366 if (mcopy) 1367 m_freem(mcopy); 1368 return; 1369 } 1370 } 1371 if (mcopy == NULL) 1372 return; 1373 1374 switch (error) { 1375 1376 case 0: /* forwarded, but need redirect */ 1377 /* type, code set above */ 1378 break; 1379 1380 case ENETUNREACH: /* shouldn't happen, checked above */ 1381 case EHOSTUNREACH: 1382 case ENETDOWN: 1383 case EHOSTDOWN: 1384 default: 1385 type = ICMP_UNREACH; 1386 code = ICMP_UNREACH_HOST; 1387 break; 1388 1389 case EMSGSIZE: 1390 type = ICMP_UNREACH; 1391 code = ICMP_UNREACH_NEEDFRAG; 1392 1393 #ifdef IPSEC 1394 mtu = ip_ipsec_mtu(m); 1395 #endif /* IPSEC */ 1396 /* 1397 * If the MTU wasn't set before use the interface mtu or 1398 * fall back to the next smaller mtu step compared to the 1399 * current packet size. 1400 */ 1401 if (mtu == 0) { 1402 if (ia != NULL) 1403 mtu = ia->ia_ifp->if_mtu; 1404 else 1405 mtu = ip_next_mtu(ip->ip_len, 0); 1406 } 1407 ipstat.ips_cantfrag++; 1408 break; 1409 1410 case ENOBUFS: 1411 /* 1412 * A router should not generate ICMP_SOURCEQUENCH as 1413 * required in RFC1812 Requirements for IP Version 4 Routers. 1414 * Source quench could be a big problem under DoS attacks, 1415 * or if the underlying interface is rate-limited. 1416 * Those who need source quench packets may re-enable them 1417 * via the net.inet.ip.sendsourcequench sysctl. 1418 */ 1419 if (ip_sendsourcequench == 0) { 1420 m_freem(mcopy); 1421 return; 1422 } else { 1423 type = ICMP_SOURCEQUENCH; 1424 code = 0; 1425 } 1426 break; 1427 1428 case EACCES: /* ipfw denied packet */ 1429 m_freem(mcopy); 1430 return; 1431 } 1432 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1433 } 1434 1435 void 1436 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1437 struct mbuf *m) 1438 { 1439 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1440 struct bintime bt; 1441 1442 bintime(&bt); 1443 if (inp->inp_socket->so_options & SO_BINTIME) { 1444 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 1445 SCM_BINTIME, SOL_SOCKET); 1446 if (*mp) 1447 mp = &(*mp)->m_next; 1448 } 1449 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1450 struct timeval tv; 1451 1452 bintime2timeval(&bt, &tv); 1453 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1454 SCM_TIMESTAMP, SOL_SOCKET); 1455 if (*mp) 1456 mp = &(*mp)->m_next; 1457 } 1458 } 1459 if (inp->inp_flags & INP_RECVDSTADDR) { 1460 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1461 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1462 if (*mp) 1463 mp = &(*mp)->m_next; 1464 } 1465 if (inp->inp_flags & INP_RECVTTL) { 1466 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1467 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1468 if (*mp) 1469 mp = &(*mp)->m_next; 1470 } 1471 #ifdef notyet 1472 /* XXX 1473 * Moving these out of udp_input() made them even more broken 1474 * than they already were. 1475 */ 1476 /* options were tossed already */ 1477 if (inp->inp_flags & INP_RECVOPTS) { 1478 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1479 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1480 if (*mp) 1481 mp = &(*mp)->m_next; 1482 } 1483 /* ip_srcroute doesn't do what we want here, need to fix */ 1484 if (inp->inp_flags & INP_RECVRETOPTS) { 1485 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1486 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1487 if (*mp) 1488 mp = &(*mp)->m_next; 1489 } 1490 #endif 1491 if (inp->inp_flags & INP_RECVIF) { 1492 struct ifnet *ifp; 1493 struct sdlbuf { 1494 struct sockaddr_dl sdl; 1495 u_char pad[32]; 1496 } sdlbuf; 1497 struct sockaddr_dl *sdp; 1498 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1499 1500 if (((ifp = m->m_pkthdr.rcvif)) 1501 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1502 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1503 /* 1504 * Change our mind and don't try copy. 1505 */ 1506 if ((sdp->sdl_family != AF_LINK) 1507 || (sdp->sdl_len > sizeof(sdlbuf))) { 1508 goto makedummy; 1509 } 1510 bcopy(sdp, sdl2, sdp->sdl_len); 1511 } else { 1512 makedummy: 1513 sdl2->sdl_len 1514 = offsetof(struct sockaddr_dl, sdl_data[0]); 1515 sdl2->sdl_family = AF_LINK; 1516 sdl2->sdl_index = 0; 1517 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1518 } 1519 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1520 IP_RECVIF, IPPROTO_IP); 1521 if (*mp) 1522 mp = &(*mp)->m_next; 1523 } 1524 } 1525 1526 /* 1527 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the 1528 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on 1529 * locking. This code remains in ip_input.c as ip_mroute.c is optionally 1530 * compiled. 1531 */ 1532 static int ip_rsvp_on; 1533 struct socket *ip_rsvpd; 1534 int 1535 ip_rsvp_init(struct socket *so) 1536 { 1537 if (so->so_type != SOCK_RAW || 1538 so->so_proto->pr_protocol != IPPROTO_RSVP) 1539 return EOPNOTSUPP; 1540 1541 if (ip_rsvpd != NULL) 1542 return EADDRINUSE; 1543 1544 ip_rsvpd = so; 1545 /* 1546 * This may seem silly, but we need to be sure we don't over-increment 1547 * the RSVP counter, in case something slips up. 1548 */ 1549 if (!ip_rsvp_on) { 1550 ip_rsvp_on = 1; 1551 rsvp_on++; 1552 } 1553 1554 return 0; 1555 } 1556 1557 int 1558 ip_rsvp_done(void) 1559 { 1560 ip_rsvpd = NULL; 1561 /* 1562 * This may seem silly, but we need to be sure we don't over-decrement 1563 * the RSVP counter, in case something slips up. 1564 */ 1565 if (ip_rsvp_on) { 1566 ip_rsvp_on = 0; 1567 rsvp_on--; 1568 } 1569 return 0; 1570 } 1571 1572 void 1573 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1574 { 1575 if (rsvp_input_p) { /* call the real one if loaded */ 1576 rsvp_input_p(m, off); 1577 return; 1578 } 1579 1580 /* Can still get packets with rsvp_on = 0 if there is a local member 1581 * of the group to which the RSVP packet is addressed. But in this 1582 * case we want to throw the packet away. 1583 */ 1584 1585 if (!rsvp_on) { 1586 m_freem(m); 1587 return; 1588 } 1589 1590 if (ip_rsvpd != NULL) { 1591 rip_input(m, off); 1592 return; 1593 } 1594 /* Drop the packet */ 1595 m_freem(m); 1596 } 1597