Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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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 * $FreeBSD$ 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/mac.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/syslog.h> 52 #include <sys/sysctl.h> 53 54 #include <net/pfil.h> 55 #include <net/if.h> 56 #include <net/if_types.h> 57 #include <net/if_var.h> 58 #include <net/if_dl.h> 59 #include <net/route.h> 60 #include <net/netisr.h> 61 62 #include <netinet/in.h> 63 #include <netinet/in_systm.h> 64 #include <netinet/in_var.h> 65 #include <netinet/ip.h> 66 #include <netinet/in_pcb.h> 67 #include <netinet/ip_var.h> 68 #include <netinet/ip_icmp.h> 69 #include <machine/in_cksum.h> 70 #ifdef DEV_CARP 71 #include <netinet/ip_carp.h> 72 #endif 73 74 #include <sys/socketvar.h> 75 76 /* XXX: Temporary until ipfw_ether and ipfw_bridge are converted. */ 77 #include <netinet/ip_fw.h> 78 #include <netinet/ip_dummynet.h> 79 80 #ifdef IPSEC 81 #include <netinet6/ipsec.h> 82 #include <netkey/key.h> 83 #endif 84 85 #ifdef FAST_IPSEC 86 #include <netipsec/ipsec.h> 87 #include <netipsec/key.h> 88 #endif 89 90 int rsvp_on = 0; 91 92 int ipforwarding = 0; 93 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 94 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 95 96 static int ipsendredirects = 1; /* XXX */ 97 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 98 &ipsendredirects, 0, "Enable sending IP redirects"); 99 100 int ip_defttl = IPDEFTTL; 101 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 102 &ip_defttl, 0, "Maximum TTL on IP packets"); 103 104 static int ip_dosourceroute = 0; 105 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 106 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 107 108 static int ip_acceptsourceroute = 0; 109 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 110 CTLFLAG_RW, &ip_acceptsourceroute, 0, 111 "Enable accepting source routed IP packets"); 112 113 int ip_doopts = 1; /* 0 = ignore, 1 = process, 2 = reject */ 114 SYSCTL_INT(_net_inet_ip, OID_AUTO, process_options, CTLFLAG_RW, 115 &ip_doopts, 0, "Enable IP options processing ([LS]SRR, RR, TS)"); 116 117 static int ip_keepfaith = 0; 118 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 119 &ip_keepfaith, 0, 120 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 121 122 static int nipq = 0; /* total # of reass queues */ 123 static int maxnipq; 124 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 125 &maxnipq, 0, 126 "Maximum number of IPv4 fragment reassembly queue entries"); 127 128 static int maxfragsperpacket; 129 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 130 &maxfragsperpacket, 0, 131 "Maximum number of IPv4 fragments allowed per packet"); 132 133 static int ip_sendsourcequench = 0; 134 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 135 &ip_sendsourcequench, 0, 136 "Enable the transmission of source quench packets"); 137 138 int ip_do_randomid = 0; 139 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 140 &ip_do_randomid, 0, 141 "Assign random ip_id values"); 142 143 /* 144 * XXX - Setting ip_checkinterface mostly implements the receive side of 145 * the Strong ES model described in RFC 1122, but since the routing table 146 * and transmit implementation do not implement the Strong ES model, 147 * setting this to 1 results in an odd hybrid. 148 * 149 * XXX - ip_checkinterface currently must be disabled if you use ipnat 150 * to translate the destination address to another local interface. 151 * 152 * XXX - ip_checkinterface must be disabled if you add IP aliases 153 * to the loopback interface instead of the interface where the 154 * packets for those addresses are received. 155 */ 156 static int ip_checkinterface = 0; 157 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 158 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 159 160 #ifdef DIAGNOSTIC 161 static int ipprintfs = 0; 162 #endif 163 164 struct pfil_head inet_pfil_hook; 165 166 static struct ifqueue ipintrq; 167 static int ipqmaxlen = IFQ_MAXLEN; 168 169 extern struct domain inetdomain; 170 extern struct protosw inetsw[]; 171 u_char ip_protox[IPPROTO_MAX]; 172 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 173 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 174 u_long in_ifaddrhmask; /* mask for hash table */ 175 176 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 177 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 178 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 179 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 180 181 struct ipstat ipstat; 182 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 183 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 184 185 /* Packet reassembly stuff */ 186 #define IPREASS_NHASH_LOG2 6 187 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 188 #define IPREASS_HMASK (IPREASS_NHASH - 1) 189 #define IPREASS_HASH(x,y) \ 190 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 191 192 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 193 struct mtx ipqlock; 194 struct callout ipport_tick_callout; 195 196 #define IPQ_LOCK() mtx_lock(&ipqlock) 197 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 198 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 199 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 200 201 #ifdef IPCTL_DEFMTU 202 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 203 &ip_mtu, 0, "Default MTU"); 204 #endif 205 206 #ifdef IPSTEALTH 207 int ipstealth = 0; 208 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 209 &ipstealth, 0, ""); 210 #endif 211 212 /* 213 * ipfw_ether and ipfw_bridge hooks. 214 * XXX: Temporary until those are converted to pfil_hooks as well. 215 */ 216 ip_fw_chk_t *ip_fw_chk_ptr = NULL; 217 ip_dn_io_t *ip_dn_io_ptr = NULL; 218 int fw_enable = 1; 219 int fw_one_pass = 1; 220 221 /* 222 * XXX this is ugly. IP options source routing magic. 223 */ 224 struct ipoptrt { 225 struct in_addr dst; /* final destination */ 226 char nop; /* one NOP to align */ 227 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 228 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 229 }; 230 231 struct ipopt_tag { 232 struct m_tag tag; 233 int ip_nhops; 234 struct ipoptrt ip_srcrt; 235 }; 236 237 static void save_rte(struct mbuf *, u_char *, struct in_addr); 238 static int ip_dooptions(struct mbuf *m, int); 239 static void ip_forward(struct mbuf *m, int srcrt); 240 static void ip_freef(struct ipqhead *, struct ipq *); 241 242 /* 243 * IP initialization: fill in IP protocol switch table. 244 * All protocols not implemented in kernel go to raw IP protocol handler. 245 */ 246 void 247 ip_init() 248 { 249 register struct protosw *pr; 250 register int i; 251 252 TAILQ_INIT(&in_ifaddrhead); 253 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 254 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 255 if (pr == NULL) 256 panic("ip_init: PF_INET not found"); 257 258 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 259 for (i = 0; i < IPPROTO_MAX; i++) 260 ip_protox[i] = pr - inetsw; 261 /* 262 * Cycle through IP protocols and put them into the appropriate place 263 * in ip_protox[]. 264 */ 265 for (pr = inetdomain.dom_protosw; 266 pr < inetdomain.dom_protoswNPROTOSW; pr++) 267 if (pr->pr_domain->dom_family == PF_INET && 268 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 269 /* Be careful to only index valid IP protocols. */ 270 if (pr->pr_protocol && pr->pr_protocol < IPPROTO_MAX) 271 ip_protox[pr->pr_protocol] = pr - inetsw; 272 } 273 274 /* Initialize packet filter hooks. */ 275 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 276 inet_pfil_hook.ph_af = AF_INET; 277 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 278 printf("%s: WARNING: unable to register pfil hook, " 279 "error %d\n", __func__, i); 280 281 /* Initialize IP reassembly queue. */ 282 IPQ_LOCK_INIT(); 283 for (i = 0; i < IPREASS_NHASH; i++) 284 TAILQ_INIT(&ipq[i]); 285 maxnipq = nmbclusters / 32; 286 maxfragsperpacket = 16; 287 288 /* Start ipport_tick. */ 289 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE); 290 ipport_tick(NULL); 291 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL, 292 SHUTDOWN_PRI_DEFAULT); 293 294 /* Initialize various other remaining things. */ 295 ip_id = time_second & 0xffff; 296 ipintrq.ifq_maxlen = ipqmaxlen; 297 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 298 netisr_register(NETISR_IP, ip_input, &ipintrq, NETISR_MPSAFE); 299 } 300 301 void ip_fini(xtp) 302 void *xtp; 303 { 304 callout_stop(&ipport_tick_callout); 305 } 306 307 /* 308 * Ip input routine. Checksum and byte swap header. If fragmented 309 * try to reassemble. Process options. Pass to next level. 310 */ 311 void 312 ip_input(struct mbuf *m) 313 { 314 struct ip *ip = NULL; 315 struct in_ifaddr *ia = NULL; 316 struct ifaddr *ifa; 317 int checkif, hlen = 0; 318 u_short sum; 319 int dchg = 0; /* dest changed after fw */ 320 struct in_addr odst; /* original dst address */ 321 #ifdef FAST_IPSEC 322 struct m_tag *mtag; 323 struct tdb_ident *tdbi; 324 struct secpolicy *sp; 325 int s, error; 326 #endif /* FAST_IPSEC */ 327 328 M_ASSERTPKTHDR(m); 329 330 if (m->m_flags & M_FASTFWD_OURS) { 331 /* 332 * Firewall or NAT changed destination to local. 333 * We expect ip_len and ip_off to be in host byte order. 334 */ 335 m->m_flags &= ~M_FASTFWD_OURS; 336 /* Set up some basics that will be used later. */ 337 ip = mtod(m, struct ip *); 338 hlen = ip->ip_hl << 2; 339 goto ours; 340 } 341 342 ipstat.ips_total++; 343 344 if (m->m_pkthdr.len < sizeof(struct ip)) 345 goto tooshort; 346 347 if (m->m_len < sizeof (struct ip) && 348 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 349 ipstat.ips_toosmall++; 350 return; 351 } 352 ip = mtod(m, struct ip *); 353 354 if (ip->ip_v != IPVERSION) { 355 ipstat.ips_badvers++; 356 goto bad; 357 } 358 359 hlen = ip->ip_hl << 2; 360 if (hlen < sizeof(struct ip)) { /* minimum header length */ 361 ipstat.ips_badhlen++; 362 goto bad; 363 } 364 if (hlen > m->m_len) { 365 if ((m = m_pullup(m, hlen)) == NULL) { 366 ipstat.ips_badhlen++; 367 return; 368 } 369 ip = mtod(m, struct ip *); 370 } 371 372 /* 127/8 must not appear on wire - RFC1122 */ 373 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 374 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 375 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 376 ipstat.ips_badaddr++; 377 goto bad; 378 } 379 } 380 381 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 382 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 383 } else { 384 if (hlen == sizeof(struct ip)) { 385 sum = in_cksum_hdr(ip); 386 } else { 387 sum = in_cksum(m, hlen); 388 } 389 } 390 if (sum) { 391 ipstat.ips_badsum++; 392 goto bad; 393 } 394 395 #ifdef ALTQ 396 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 397 /* packet is dropped by traffic conditioner */ 398 return; 399 #endif 400 401 /* 402 * Convert fields to host representation. 403 */ 404 ip->ip_len = ntohs(ip->ip_len); 405 if (ip->ip_len < hlen) { 406 ipstat.ips_badlen++; 407 goto bad; 408 } 409 ip->ip_off = ntohs(ip->ip_off); 410 411 /* 412 * Check that the amount of data in the buffers 413 * is as at least much as the IP header would have us expect. 414 * Trim mbufs if longer than we expect. 415 * Drop packet if shorter than we expect. 416 */ 417 if (m->m_pkthdr.len < ip->ip_len) { 418 tooshort: 419 ipstat.ips_tooshort++; 420 goto bad; 421 } 422 if (m->m_pkthdr.len > ip->ip_len) { 423 if (m->m_len == m->m_pkthdr.len) { 424 m->m_len = ip->ip_len; 425 m->m_pkthdr.len = ip->ip_len; 426 } else 427 m_adj(m, ip->ip_len - m->m_pkthdr.len); 428 } 429 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 430 /* 431 * Bypass packet filtering for packets from a tunnel (gif). 432 */ 433 if (ipsec_getnhist(m)) 434 goto passin; 435 #endif 436 #if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF) 437 /* 438 * Bypass packet filtering for packets from a tunnel (gif). 439 */ 440 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 441 goto passin; 442 #endif 443 444 /* 445 * Run through list of hooks for input packets. 446 * 447 * NB: Beware of the destination address changing (e.g. 448 * by NAT rewriting). When this happens, tell 449 * ip_forward to do the right thing. 450 */ 451 452 /* Jump over all PFIL processing if hooks are not active. */ 453 if (inet_pfil_hook.ph_busy_count == -1) 454 goto passin; 455 456 odst = ip->ip_dst; 457 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 458 PFIL_IN, NULL) != 0) 459 return; 460 if (m == NULL) /* consumed by filter */ 461 return; 462 463 ip = mtod(m, struct ip *); 464 dchg = (odst.s_addr != ip->ip_dst.s_addr); 465 466 #ifdef IPFIREWALL_FORWARD 467 if (m->m_flags & M_FASTFWD_OURS) { 468 m->m_flags &= ~M_FASTFWD_OURS; 469 goto ours; 470 } 471 #ifndef IPFIREWALL_FORWARD_EXTENDED 472 dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL); 473 #else 474 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 475 /* 476 * Directly ship on the packet. This allows to forward packets 477 * that were destined for us to some other directly connected 478 * host. 479 */ 480 ip_forward(m, dchg); 481 return; 482 } 483 #endif /* IPFIREWALL_FORWARD_EXTENDED */ 484 #endif /* IPFIREWALL_FORWARD */ 485 486 passin: 487 /* 488 * Process options and, if not destined for us, 489 * ship it on. ip_dooptions returns 1 when an 490 * error was detected (causing an icmp message 491 * to be sent and the original packet to be freed). 492 */ 493 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 494 return; 495 496 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 497 * matter if it is destined to another node, or whether it is 498 * a multicast one, RSVP wants it! and prevents it from being forwarded 499 * anywhere else. Also checks if the rsvp daemon is running before 500 * grabbing the packet. 501 */ 502 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 503 goto ours; 504 505 /* 506 * Check our list of addresses, to see if the packet is for us. 507 * If we don't have any addresses, assume any unicast packet 508 * we receive might be for us (and let the upper layers deal 509 * with it). 510 */ 511 if (TAILQ_EMPTY(&in_ifaddrhead) && 512 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 513 goto ours; 514 515 /* 516 * Enable a consistency check between the destination address 517 * and the arrival interface for a unicast packet (the RFC 1122 518 * strong ES model) if IP forwarding is disabled and the packet 519 * is not locally generated and the packet is not subject to 520 * 'ipfw fwd'. 521 * 522 * XXX - Checking also should be disabled if the destination 523 * address is ipnat'ed to a different interface. 524 * 525 * XXX - Checking is incompatible with IP aliases added 526 * to the loopback interface instead of the interface where 527 * the packets are received. 528 * 529 * XXX - This is the case for carp vhost IPs as well so we 530 * insert a workaround. If the packet got here, we already 531 * checked with carp_iamatch() and carp_forus(). 532 */ 533 checkif = ip_checkinterface && (ipforwarding == 0) && 534 m->m_pkthdr.rcvif != NULL && 535 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 536 #ifdef DEV_CARP 537 !m->m_pkthdr.rcvif->if_carp && 538 #endif 539 (dchg == 0); 540 541 /* 542 * Check for exact addresses in the hash bucket. 543 */ 544 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 545 /* 546 * If the address matches, verify that the packet 547 * arrived via the correct interface if checking is 548 * enabled. 549 */ 550 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 551 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 552 goto ours; 553 } 554 /* 555 * Check for broadcast addresses. 556 * 557 * Only accept broadcast packets that arrive via the matching 558 * interface. Reception of forwarded directed broadcasts would 559 * be handled via ip_forward() and ether_output() with the loopback 560 * into the stack for SIMPLEX interfaces handled by ether_output(). 561 */ 562 if (m->m_pkthdr.rcvif != NULL && 563 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 564 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 565 if (ifa->ifa_addr->sa_family != AF_INET) 566 continue; 567 ia = ifatoia(ifa); 568 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 569 ip->ip_dst.s_addr) 570 goto ours; 571 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 572 goto ours; 573 #ifdef BOOTP_COMPAT 574 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 575 goto ours; 576 #endif 577 } 578 } 579 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 580 struct in_multi *inm; 581 if (ip_mrouter) { 582 /* 583 * If we are acting as a multicast router, all 584 * incoming multicast packets are passed to the 585 * kernel-level multicast forwarding function. 586 * The packet is returned (relatively) intact; if 587 * ip_mforward() returns a non-zero value, the packet 588 * must be discarded, else it may be accepted below. 589 */ 590 if (ip_mforward && 591 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 592 ipstat.ips_cantforward++; 593 m_freem(m); 594 return; 595 } 596 597 /* 598 * The process-level routing daemon needs to receive 599 * all multicast IGMP packets, whether or not this 600 * host belongs to their destination groups. 601 */ 602 if (ip->ip_p == IPPROTO_IGMP) 603 goto ours; 604 ipstat.ips_forward++; 605 } 606 /* 607 * See if we belong to the destination multicast group on the 608 * arrival interface. 609 */ 610 IN_MULTI_LOCK(); 611 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 612 IN_MULTI_UNLOCK(); 613 if (inm == NULL) { 614 ipstat.ips_notmember++; 615 m_freem(m); 616 return; 617 } 618 goto ours; 619 } 620 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 621 goto ours; 622 if (ip->ip_dst.s_addr == INADDR_ANY) 623 goto ours; 624 625 /* 626 * FAITH(Firewall Aided Internet Translator) 627 */ 628 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 629 if (ip_keepfaith) { 630 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 631 goto ours; 632 } 633 m_freem(m); 634 return; 635 } 636 637 /* 638 * Not for us; forward if possible and desirable. 639 */ 640 if (ipforwarding == 0) { 641 ipstat.ips_cantforward++; 642 m_freem(m); 643 } else { 644 #ifdef IPSEC 645 /* 646 * Enforce inbound IPsec SPD. 647 */ 648 if (ipsec4_in_reject(m, NULL)) { 649 ipsecstat.in_polvio++; 650 goto bad; 651 } 652 #endif /* IPSEC */ 653 #ifdef FAST_IPSEC 654 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 655 s = splnet(); 656 if (mtag != NULL) { 657 tdbi = (struct tdb_ident *)(mtag + 1); 658 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 659 } else { 660 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 661 IP_FORWARDING, &error); 662 } 663 if (sp == NULL) { /* NB: can happen if error */ 664 splx(s); 665 /*XXX error stat???*/ 666 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 667 goto bad; 668 } 669 670 /* 671 * Check security policy against packet attributes. 672 */ 673 error = ipsec_in_reject(sp, m); 674 KEY_FREESP(&sp); 675 splx(s); 676 if (error) { 677 ipstat.ips_cantforward++; 678 goto bad; 679 } 680 #endif /* FAST_IPSEC */ 681 ip_forward(m, dchg); 682 } 683 return; 684 685 ours: 686 #ifdef IPSTEALTH 687 /* 688 * IPSTEALTH: Process non-routing options only 689 * if the packet is destined for us. 690 */ 691 if (ipstealth && hlen > sizeof (struct ip) && 692 ip_dooptions(m, 1)) 693 return; 694 #endif /* IPSTEALTH */ 695 696 /* Count the packet in the ip address stats */ 697 if (ia != NULL) { 698 ia->ia_ifa.if_ipackets++; 699 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 700 } 701 702 /* 703 * Attempt reassembly; if it succeeds, proceed. 704 * ip_reass() will return a different mbuf. 705 */ 706 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 707 m = ip_reass(m); 708 if (m == NULL) 709 return; 710 ip = mtod(m, struct ip *); 711 /* Get the header length of the reassembled packet */ 712 hlen = ip->ip_hl << 2; 713 } 714 715 /* 716 * Further protocols expect the packet length to be w/o the 717 * IP header. 718 */ 719 ip->ip_len -= hlen; 720 721 #ifdef IPSEC 722 /* 723 * enforce IPsec policy checking if we are seeing last header. 724 * note that we do not visit this with protocols with pcb layer 725 * code - like udp/tcp/raw ip. 726 */ 727 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 728 ipsec4_in_reject(m, NULL)) { 729 ipsecstat.in_polvio++; 730 goto bad; 731 } 732 #endif 733 #if FAST_IPSEC 734 /* 735 * enforce IPsec policy checking if we are seeing last header. 736 * note that we do not visit this with protocols with pcb layer 737 * code - like udp/tcp/raw ip. 738 */ 739 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 740 /* 741 * Check if the packet has already had IPsec processing 742 * done. If so, then just pass it along. This tag gets 743 * set during AH, ESP, etc. input handling, before the 744 * packet is returned to the ip input queue for delivery. 745 */ 746 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 747 s = splnet(); 748 if (mtag != NULL) { 749 tdbi = (struct tdb_ident *)(mtag + 1); 750 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 751 } else { 752 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 753 IP_FORWARDING, &error); 754 } 755 if (sp != NULL) { 756 /* 757 * Check security policy against packet attributes. 758 */ 759 error = ipsec_in_reject(sp, m); 760 KEY_FREESP(&sp); 761 } else { 762 /* XXX error stat??? */ 763 error = EINVAL; 764 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 765 goto bad; 766 } 767 splx(s); 768 if (error) 769 goto bad; 770 } 771 #endif /* FAST_IPSEC */ 772 773 /* 774 * Switch out to protocol's input routine. 775 */ 776 ipstat.ips_delivered++; 777 778 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 779 return; 780 bad: 781 m_freem(m); 782 } 783 784 /* 785 * Take incoming datagram fragment and try to reassemble it into 786 * whole datagram. If the argument is the first fragment or one 787 * in between the function will return NULL and store the mbuf 788 * in the fragment chain. If the argument is the last fragment 789 * the packet will be reassembled and the pointer to the new 790 * mbuf returned for further processing. Only m_tags attached 791 * to the first packet/fragment are preserved. 792 * The IP header is *NOT* adjusted out of iplen. 793 */ 794 795 struct mbuf * 796 ip_reass(struct mbuf *m) 797 { 798 struct ip *ip; 799 struct mbuf *p, *q, *nq, *t; 800 struct ipq *fp = NULL; 801 struct ipqhead *head; 802 int i, hlen, next; 803 u_int8_t ecn, ecn0; 804 u_short hash; 805 806 /* If maxnipq is 0, never accept fragments. */ 807 if (maxnipq == 0) { 808 ipstat.ips_fragments++; 809 ipstat.ips_fragdropped++; 810 m_freem(m); 811 return (NULL); 812 } 813 814 ip = mtod(m, struct ip *); 815 hlen = ip->ip_hl << 2; 816 817 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 818 head = &ipq[hash]; 819 IPQ_LOCK(); 820 821 /* 822 * Look for queue of fragments 823 * of this datagram. 824 */ 825 TAILQ_FOREACH(fp, head, ipq_list) 826 if (ip->ip_id == fp->ipq_id && 827 ip->ip_src.s_addr == fp->ipq_src.s_addr && 828 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 829 #ifdef MAC 830 mac_fragment_match(m, fp) && 831 #endif 832 ip->ip_p == fp->ipq_p) 833 goto found; 834 835 fp = NULL; 836 837 /* 838 * Enforce upper bound on number of fragmented packets 839 * for which we attempt reassembly; 840 * If maxnipq is -1, accept all fragments without limitation. 841 */ 842 if ((nipq > maxnipq) && (maxnipq > 0)) { 843 /* 844 * drop something from the tail of the current queue 845 * before proceeding further 846 */ 847 struct ipq *q = TAILQ_LAST(head, ipqhead); 848 if (q == NULL) { /* gak */ 849 for (i = 0; i < IPREASS_NHASH; i++) { 850 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 851 if (r) { 852 ipstat.ips_fragtimeout += r->ipq_nfrags; 853 ip_freef(&ipq[i], r); 854 break; 855 } 856 } 857 } else { 858 ipstat.ips_fragtimeout += q->ipq_nfrags; 859 ip_freef(head, q); 860 } 861 } 862 863 found: 864 /* 865 * Adjust ip_len to not reflect header, 866 * convert offset of this to bytes. 867 */ 868 ip->ip_len -= hlen; 869 if (ip->ip_off & IP_MF) { 870 /* 871 * Make sure that fragments have a data length 872 * that's a non-zero multiple of 8 bytes. 873 */ 874 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 875 ipstat.ips_toosmall++; /* XXX */ 876 goto dropfrag; 877 } 878 m->m_flags |= M_FRAG; 879 } else 880 m->m_flags &= ~M_FRAG; 881 ip->ip_off <<= 3; 882 883 884 /* 885 * Attempt reassembly; if it succeeds, proceed. 886 * ip_reass() will return a different mbuf. 887 */ 888 ipstat.ips_fragments++; 889 m->m_pkthdr.header = ip; 890 891 /* Previous ip_reass() started here. */ 892 /* 893 * Presence of header sizes in mbufs 894 * would confuse code below. 895 */ 896 m->m_data += hlen; 897 m->m_len -= hlen; 898 899 /* 900 * If first fragment to arrive, create a reassembly queue. 901 */ 902 if (fp == NULL) { 903 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 904 goto dropfrag; 905 fp = mtod(t, struct ipq *); 906 #ifdef MAC 907 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 908 m_free(t); 909 goto dropfrag; 910 } 911 mac_create_ipq(m, fp); 912 #endif 913 TAILQ_INSERT_HEAD(head, fp, ipq_list); 914 nipq++; 915 fp->ipq_nfrags = 1; 916 fp->ipq_ttl = IPFRAGTTL; 917 fp->ipq_p = ip->ip_p; 918 fp->ipq_id = ip->ip_id; 919 fp->ipq_src = ip->ip_src; 920 fp->ipq_dst = ip->ip_dst; 921 fp->ipq_frags = m; 922 m->m_nextpkt = NULL; 923 goto inserted; 924 } else { 925 fp->ipq_nfrags++; 926 #ifdef MAC 927 mac_update_ipq(m, fp); 928 #endif 929 } 930 931 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 932 933 /* 934 * Handle ECN by comparing this segment with the first one; 935 * if CE is set, do not lose CE. 936 * drop if CE and not-ECT are mixed for the same packet. 937 */ 938 ecn = ip->ip_tos & IPTOS_ECN_MASK; 939 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 940 if (ecn == IPTOS_ECN_CE) { 941 if (ecn0 == IPTOS_ECN_NOTECT) 942 goto dropfrag; 943 if (ecn0 != IPTOS_ECN_CE) 944 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 945 } 946 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 947 goto dropfrag; 948 949 /* 950 * Find a segment which begins after this one does. 951 */ 952 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 953 if (GETIP(q)->ip_off > ip->ip_off) 954 break; 955 956 /* 957 * If there is a preceding segment, it may provide some of 958 * our data already. If so, drop the data from the incoming 959 * segment. If it provides all of our data, drop us, otherwise 960 * stick new segment in the proper place. 961 * 962 * If some of the data is dropped from the the preceding 963 * segment, then it's checksum is invalidated. 964 */ 965 if (p) { 966 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 967 if (i > 0) { 968 if (i >= ip->ip_len) 969 goto dropfrag; 970 m_adj(m, i); 971 m->m_pkthdr.csum_flags = 0; 972 ip->ip_off += i; 973 ip->ip_len -= i; 974 } 975 m->m_nextpkt = p->m_nextpkt; 976 p->m_nextpkt = m; 977 } else { 978 m->m_nextpkt = fp->ipq_frags; 979 fp->ipq_frags = m; 980 } 981 982 /* 983 * While we overlap succeeding segments trim them or, 984 * if they are completely covered, dequeue them. 985 */ 986 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 987 q = nq) { 988 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 989 if (i < GETIP(q)->ip_len) { 990 GETIP(q)->ip_len -= i; 991 GETIP(q)->ip_off += i; 992 m_adj(q, i); 993 q->m_pkthdr.csum_flags = 0; 994 break; 995 } 996 nq = q->m_nextpkt; 997 m->m_nextpkt = nq; 998 ipstat.ips_fragdropped++; 999 fp->ipq_nfrags--; 1000 m_freem(q); 1001 } 1002 1003 inserted: 1004 1005 /* 1006 * Check for complete reassembly and perform frag per packet 1007 * limiting. 1008 * 1009 * Frag limiting is performed here so that the nth frag has 1010 * a chance to complete the packet before we drop the packet. 1011 * As a result, n+1 frags are actually allowed per packet, but 1012 * only n will ever be stored. (n = maxfragsperpacket.) 1013 * 1014 */ 1015 next = 0; 1016 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1017 if (GETIP(q)->ip_off != next) { 1018 if (fp->ipq_nfrags > maxfragsperpacket) { 1019 ipstat.ips_fragdropped += fp->ipq_nfrags; 1020 ip_freef(head, fp); 1021 } 1022 goto done; 1023 } 1024 next += GETIP(q)->ip_len; 1025 } 1026 /* Make sure the last packet didn't have the IP_MF flag */ 1027 if (p->m_flags & M_FRAG) { 1028 if (fp->ipq_nfrags > maxfragsperpacket) { 1029 ipstat.ips_fragdropped += fp->ipq_nfrags; 1030 ip_freef(head, fp); 1031 } 1032 goto done; 1033 } 1034 1035 /* 1036 * Reassembly is complete. Make sure the packet is a sane size. 1037 */ 1038 q = fp->ipq_frags; 1039 ip = GETIP(q); 1040 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1041 ipstat.ips_toolong++; 1042 ipstat.ips_fragdropped += fp->ipq_nfrags; 1043 ip_freef(head, fp); 1044 goto done; 1045 } 1046 1047 /* 1048 * Concatenate fragments. 1049 */ 1050 m = q; 1051 t = m->m_next; 1052 m->m_next = NULL; 1053 m_cat(m, t); 1054 nq = q->m_nextpkt; 1055 q->m_nextpkt = NULL; 1056 for (q = nq; q != NULL; q = nq) { 1057 nq = q->m_nextpkt; 1058 q->m_nextpkt = NULL; 1059 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1060 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1061 m_cat(m, q); 1062 } 1063 /* 1064 * In order to do checksumming faster we do 'end-around carry' here 1065 * (and not in for{} loop), though it implies we are not going to 1066 * reassemble more than 64k fragments. 1067 */ 1068 m->m_pkthdr.csum_data = 1069 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1070 #ifdef MAC 1071 mac_create_datagram_from_ipq(fp, m); 1072 mac_destroy_ipq(fp); 1073 #endif 1074 1075 /* 1076 * Create header for new ip packet by modifying header of first 1077 * packet; dequeue and discard fragment reassembly header. 1078 * Make header visible. 1079 */ 1080 ip->ip_len = (ip->ip_hl << 2) + next; 1081 ip->ip_src = fp->ipq_src; 1082 ip->ip_dst = fp->ipq_dst; 1083 TAILQ_REMOVE(head, fp, ipq_list); 1084 nipq--; 1085 (void) m_free(dtom(fp)); 1086 m->m_len += (ip->ip_hl << 2); 1087 m->m_data -= (ip->ip_hl << 2); 1088 /* some debugging cruft by sklower, below, will go away soon */ 1089 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1090 m_fixhdr(m); 1091 ipstat.ips_reassembled++; 1092 IPQ_UNLOCK(); 1093 return (m); 1094 1095 dropfrag: 1096 ipstat.ips_fragdropped++; 1097 if (fp != NULL) 1098 fp->ipq_nfrags--; 1099 m_freem(m); 1100 done: 1101 IPQ_UNLOCK(); 1102 return (NULL); 1103 1104 #undef GETIP 1105 } 1106 1107 /* 1108 * Free a fragment reassembly header and all 1109 * associated datagrams. 1110 */ 1111 static void 1112 ip_freef(fhp, fp) 1113 struct ipqhead *fhp; 1114 struct ipq *fp; 1115 { 1116 register struct mbuf *q; 1117 1118 IPQ_LOCK_ASSERT(); 1119 1120 while (fp->ipq_frags) { 1121 q = fp->ipq_frags; 1122 fp->ipq_frags = q->m_nextpkt; 1123 m_freem(q); 1124 } 1125 TAILQ_REMOVE(fhp, fp, ipq_list); 1126 (void) m_free(dtom(fp)); 1127 nipq--; 1128 } 1129 1130 /* 1131 * IP timer processing; 1132 * if a timer expires on a reassembly 1133 * queue, discard it. 1134 */ 1135 void 1136 ip_slowtimo() 1137 { 1138 register struct ipq *fp; 1139 int i; 1140 1141 IPQ_LOCK(); 1142 for (i = 0; i < IPREASS_NHASH; i++) { 1143 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1144 struct ipq *fpp; 1145 1146 fpp = fp; 1147 fp = TAILQ_NEXT(fp, ipq_list); 1148 if(--fpp->ipq_ttl == 0) { 1149 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1150 ip_freef(&ipq[i], fpp); 1151 } 1152 } 1153 } 1154 /* 1155 * If we are over the maximum number of fragments 1156 * (due to the limit being lowered), drain off 1157 * enough to get down to the new limit. 1158 */ 1159 if (maxnipq >= 0 && nipq > maxnipq) { 1160 for (i = 0; i < IPREASS_NHASH; i++) { 1161 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1162 ipstat.ips_fragdropped += 1163 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1164 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1165 } 1166 } 1167 } 1168 IPQ_UNLOCK(); 1169 } 1170 1171 /* 1172 * Drain off all datagram fragments. 1173 */ 1174 void 1175 ip_drain() 1176 { 1177 int i; 1178 1179 IPQ_LOCK(); 1180 for (i = 0; i < IPREASS_NHASH; i++) { 1181 while(!TAILQ_EMPTY(&ipq[i])) { 1182 ipstat.ips_fragdropped += 1183 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1184 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1185 } 1186 } 1187 IPQ_UNLOCK(); 1188 in_rtqdrain(); 1189 } 1190 1191 /* 1192 * Do option processing on a datagram, 1193 * possibly discarding it if bad options are encountered, 1194 * or forwarding it if source-routed. 1195 * The pass argument is used when operating in the IPSTEALTH 1196 * mode to tell what options to process: 1197 * [LS]SRR (pass 0) or the others (pass 1). 1198 * The reason for as many as two passes is that when doing IPSTEALTH, 1199 * non-routing options should be processed only if the packet is for us. 1200 * Returns 1 if packet has been forwarded/freed, 1201 * 0 if the packet should be processed further. 1202 */ 1203 static int 1204 ip_dooptions(struct mbuf *m, int pass) 1205 { 1206 struct ip *ip = mtod(m, struct ip *); 1207 u_char *cp; 1208 struct in_ifaddr *ia; 1209 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1210 struct in_addr *sin, dst; 1211 n_time ntime; 1212 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 1213 1214 /* ignore or reject packets with IP options */ 1215 if (ip_doopts == 0) 1216 return 0; 1217 else if (ip_doopts == 2) { 1218 type = ICMP_UNREACH; 1219 code = ICMP_UNREACH_FILTER_PROHIB; 1220 goto bad; 1221 } 1222 1223 dst = ip->ip_dst; 1224 cp = (u_char *)(ip + 1); 1225 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1226 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1227 opt = cp[IPOPT_OPTVAL]; 1228 if (opt == IPOPT_EOL) 1229 break; 1230 if (opt == IPOPT_NOP) 1231 optlen = 1; 1232 else { 1233 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1234 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1235 goto bad; 1236 } 1237 optlen = cp[IPOPT_OLEN]; 1238 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1239 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1240 goto bad; 1241 } 1242 } 1243 switch (opt) { 1244 1245 default: 1246 break; 1247 1248 /* 1249 * Source routing with record. 1250 * Find interface with current destination address. 1251 * If none on this machine then drop if strictly routed, 1252 * or do nothing if loosely routed. 1253 * Record interface address and bring up next address 1254 * component. If strictly routed make sure next 1255 * address is on directly accessible net. 1256 */ 1257 case IPOPT_LSRR: 1258 case IPOPT_SSRR: 1259 #ifdef IPSTEALTH 1260 if (ipstealth && pass > 0) 1261 break; 1262 #endif 1263 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1264 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1265 goto bad; 1266 } 1267 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1268 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1269 goto bad; 1270 } 1271 ipaddr.sin_addr = ip->ip_dst; 1272 ia = (struct in_ifaddr *) 1273 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1274 if (ia == NULL) { 1275 if (opt == IPOPT_SSRR) { 1276 type = ICMP_UNREACH; 1277 code = ICMP_UNREACH_SRCFAIL; 1278 goto bad; 1279 } 1280 if (!ip_dosourceroute) 1281 goto nosourcerouting; 1282 /* 1283 * Loose routing, and not at next destination 1284 * yet; nothing to do except forward. 1285 */ 1286 break; 1287 } 1288 off--; /* 0 origin */ 1289 if (off > optlen - (int)sizeof(struct in_addr)) { 1290 /* 1291 * End of source route. Should be for us. 1292 */ 1293 if (!ip_acceptsourceroute) 1294 goto nosourcerouting; 1295 save_rte(m, cp, ip->ip_src); 1296 break; 1297 } 1298 #ifdef IPSTEALTH 1299 if (ipstealth) 1300 goto dropit; 1301 #endif 1302 if (!ip_dosourceroute) { 1303 if (ipforwarding) { 1304 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1305 /* 1306 * Acting as a router, so generate ICMP 1307 */ 1308 nosourcerouting: 1309 strcpy(buf, inet_ntoa(ip->ip_dst)); 1310 log(LOG_WARNING, 1311 "attempted source route from %s to %s\n", 1312 inet_ntoa(ip->ip_src), buf); 1313 type = ICMP_UNREACH; 1314 code = ICMP_UNREACH_SRCFAIL; 1315 goto bad; 1316 } else { 1317 /* 1318 * Not acting as a router, so silently drop. 1319 */ 1320 #ifdef IPSTEALTH 1321 dropit: 1322 #endif 1323 ipstat.ips_cantforward++; 1324 m_freem(m); 1325 return (1); 1326 } 1327 } 1328 1329 /* 1330 * locate outgoing interface 1331 */ 1332 (void)memcpy(&ipaddr.sin_addr, cp + off, 1333 sizeof(ipaddr.sin_addr)); 1334 1335 if (opt == IPOPT_SSRR) { 1336 #define INA struct in_ifaddr * 1337 #define SA struct sockaddr * 1338 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == NULL) 1339 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1340 } else 1341 ia = ip_rtaddr(ipaddr.sin_addr); 1342 if (ia == NULL) { 1343 type = ICMP_UNREACH; 1344 code = ICMP_UNREACH_SRCFAIL; 1345 goto bad; 1346 } 1347 ip->ip_dst = ipaddr.sin_addr; 1348 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1349 sizeof(struct in_addr)); 1350 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1351 /* 1352 * Let ip_intr's mcast routing check handle mcast pkts 1353 */ 1354 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1355 break; 1356 1357 case IPOPT_RR: 1358 #ifdef IPSTEALTH 1359 if (ipstealth && pass == 0) 1360 break; 1361 #endif 1362 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1363 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1364 goto bad; 1365 } 1366 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1367 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1368 goto bad; 1369 } 1370 /* 1371 * If no space remains, ignore. 1372 */ 1373 off--; /* 0 origin */ 1374 if (off > optlen - (int)sizeof(struct in_addr)) 1375 break; 1376 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1377 sizeof(ipaddr.sin_addr)); 1378 /* 1379 * locate outgoing interface; if we're the destination, 1380 * use the incoming interface (should be same). 1381 */ 1382 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1383 (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) { 1384 type = ICMP_UNREACH; 1385 code = ICMP_UNREACH_HOST; 1386 goto bad; 1387 } 1388 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1389 sizeof(struct in_addr)); 1390 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1391 break; 1392 1393 case IPOPT_TS: 1394 #ifdef IPSTEALTH 1395 if (ipstealth && pass == 0) 1396 break; 1397 #endif 1398 code = cp - (u_char *)ip; 1399 if (optlen < 4 || optlen > 40) { 1400 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1401 goto bad; 1402 } 1403 if ((off = cp[IPOPT_OFFSET]) < 5) { 1404 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1405 goto bad; 1406 } 1407 if (off > optlen - (int)sizeof(int32_t)) { 1408 cp[IPOPT_OFFSET + 1] += (1 << 4); 1409 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1410 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1411 goto bad; 1412 } 1413 break; 1414 } 1415 off--; /* 0 origin */ 1416 sin = (struct in_addr *)(cp + off); 1417 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1418 1419 case IPOPT_TS_TSONLY: 1420 break; 1421 1422 case IPOPT_TS_TSANDADDR: 1423 if (off + sizeof(n_time) + 1424 sizeof(struct in_addr) > optlen) { 1425 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1426 goto bad; 1427 } 1428 ipaddr.sin_addr = dst; 1429 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1430 m->m_pkthdr.rcvif); 1431 if (ia == NULL) 1432 continue; 1433 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1434 sizeof(struct in_addr)); 1435 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1436 off += sizeof(struct in_addr); 1437 break; 1438 1439 case IPOPT_TS_PRESPEC: 1440 if (off + sizeof(n_time) + 1441 sizeof(struct in_addr) > optlen) { 1442 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1443 goto bad; 1444 } 1445 (void)memcpy(&ipaddr.sin_addr, sin, 1446 sizeof(struct in_addr)); 1447 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1448 continue; 1449 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1450 off += sizeof(struct in_addr); 1451 break; 1452 1453 default: 1454 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1455 goto bad; 1456 } 1457 ntime = iptime(); 1458 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1459 cp[IPOPT_OFFSET] += sizeof(n_time); 1460 } 1461 } 1462 if (forward && ipforwarding) { 1463 ip_forward(m, 1); 1464 return (1); 1465 } 1466 return (0); 1467 bad: 1468 icmp_error(m, type, code, 0, 0); 1469 ipstat.ips_badoptions++; 1470 return (1); 1471 } 1472 1473 /* 1474 * Given address of next destination (final or next hop), 1475 * return internet address info of interface to be used to get there. 1476 */ 1477 struct in_ifaddr * 1478 ip_rtaddr(dst) 1479 struct in_addr dst; 1480 { 1481 struct route sro; 1482 struct sockaddr_in *sin; 1483 struct in_ifaddr *ifa; 1484 1485 bzero(&sro, sizeof(sro)); 1486 sin = (struct sockaddr_in *)&sro.ro_dst; 1487 sin->sin_family = AF_INET; 1488 sin->sin_len = sizeof(*sin); 1489 sin->sin_addr = dst; 1490 rtalloc_ign(&sro, RTF_CLONING); 1491 1492 if (sro.ro_rt == NULL) 1493 return (NULL); 1494 1495 ifa = ifatoia(sro.ro_rt->rt_ifa); 1496 RTFREE(sro.ro_rt); 1497 return (ifa); 1498 } 1499 1500 /* 1501 * Save incoming source route for use in replies, 1502 * to be picked up later by ip_srcroute if the receiver is interested. 1503 */ 1504 static void 1505 save_rte(m, option, dst) 1506 struct mbuf *m; 1507 u_char *option; 1508 struct in_addr dst; 1509 { 1510 unsigned olen; 1511 struct ipopt_tag *opts; 1512 1513 opts = (struct ipopt_tag *)m_tag_get(PACKET_TAG_IPOPTIONS, 1514 sizeof(struct ipopt_tag), M_NOWAIT); 1515 if (opts == NULL) 1516 return; 1517 1518 olen = option[IPOPT_OLEN]; 1519 #ifdef DIAGNOSTIC 1520 if (ipprintfs) 1521 printf("save_rte: olen %d\n", olen); 1522 #endif 1523 if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) 1524 return; 1525 bcopy(option, opts->ip_srcrt.srcopt, olen); 1526 opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1527 opts->ip_srcrt.dst = dst; 1528 m_tag_prepend(m, (struct m_tag *)opts); 1529 } 1530 1531 /* 1532 * Retrieve incoming source route for use in replies, 1533 * in the same form used by setsockopt. 1534 * The first hop is placed before the options, will be removed later. 1535 */ 1536 struct mbuf * 1537 ip_srcroute(m0) 1538 struct mbuf *m0; 1539 { 1540 register struct in_addr *p, *q; 1541 register struct mbuf *m; 1542 struct ipopt_tag *opts; 1543 1544 opts = (struct ipopt_tag *)m_tag_find(m0, PACKET_TAG_IPOPTIONS, NULL); 1545 if (opts == NULL) 1546 return (NULL); 1547 1548 if (opts->ip_nhops == 0) 1549 return (NULL); 1550 m = m_get(M_DONTWAIT, MT_HEADER); 1551 if (m == NULL) 1552 return (NULL); 1553 1554 #define OPTSIZ (sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt)) 1555 1556 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1557 m->m_len = opts->ip_nhops * sizeof(struct in_addr) + 1558 sizeof(struct in_addr) + OPTSIZ; 1559 #ifdef DIAGNOSTIC 1560 if (ipprintfs) 1561 printf("ip_srcroute: nhops %d mlen %d", opts->ip_nhops, m->m_len); 1562 #endif 1563 1564 /* 1565 * First save first hop for return route 1566 */ 1567 p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]); 1568 *(mtod(m, struct in_addr *)) = *p--; 1569 #ifdef DIAGNOSTIC 1570 if (ipprintfs) 1571 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1572 #endif 1573 1574 /* 1575 * Copy option fields and padding (nop) to mbuf. 1576 */ 1577 opts->ip_srcrt.nop = IPOPT_NOP; 1578 opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1579 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1580 &(opts->ip_srcrt.nop), OPTSIZ); 1581 q = (struct in_addr *)(mtod(m, caddr_t) + 1582 sizeof(struct in_addr) + OPTSIZ); 1583 #undef OPTSIZ 1584 /* 1585 * Record return path as an IP source route, 1586 * reversing the path (pointers are now aligned). 1587 */ 1588 while (p >= opts->ip_srcrt.route) { 1589 #ifdef DIAGNOSTIC 1590 if (ipprintfs) 1591 printf(" %lx", (u_long)ntohl(q->s_addr)); 1592 #endif 1593 *q++ = *p--; 1594 } 1595 /* 1596 * Last hop goes to final destination. 1597 */ 1598 *q = opts->ip_srcrt.dst; 1599 #ifdef DIAGNOSTIC 1600 if (ipprintfs) 1601 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1602 #endif 1603 m_tag_delete(m0, (struct m_tag *)opts); 1604 return (m); 1605 } 1606 1607 /* 1608 * Strip out IP options, at higher 1609 * level protocol in the kernel. 1610 * Second argument is buffer to which options 1611 * will be moved, and return value is their length. 1612 * XXX should be deleted; last arg currently ignored. 1613 */ 1614 void 1615 ip_stripoptions(m, mopt) 1616 register struct mbuf *m; 1617 struct mbuf *mopt; 1618 { 1619 register int i; 1620 struct ip *ip = mtod(m, struct ip *); 1621 register caddr_t opts; 1622 int olen; 1623 1624 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1625 opts = (caddr_t)(ip + 1); 1626 i = m->m_len - (sizeof (struct ip) + olen); 1627 bcopy(opts + olen, opts, (unsigned)i); 1628 m->m_len -= olen; 1629 if (m->m_flags & M_PKTHDR) 1630 m->m_pkthdr.len -= olen; 1631 ip->ip_v = IPVERSION; 1632 ip->ip_hl = sizeof(struct ip) >> 2; 1633 } 1634 1635 u_char inetctlerrmap[PRC_NCMDS] = { 1636 0, 0, 0, 0, 1637 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1638 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1639 EMSGSIZE, EHOSTUNREACH, 0, 0, 1640 0, 0, EHOSTUNREACH, 0, 1641 ENOPROTOOPT, ECONNREFUSED 1642 }; 1643 1644 /* 1645 * Forward a packet. If some error occurs return the sender 1646 * an icmp packet. Note we can't always generate a meaningful 1647 * icmp message because icmp doesn't have a large enough repertoire 1648 * of codes and types. 1649 * 1650 * If not forwarding, just drop the packet. This could be confusing 1651 * if ipforwarding was zero but some routing protocol was advancing 1652 * us as a gateway to somewhere. However, we must let the routing 1653 * protocol deal with that. 1654 * 1655 * The srcrt parameter indicates whether the packet is being forwarded 1656 * via a source route. 1657 */ 1658 void 1659 ip_forward(struct mbuf *m, int srcrt) 1660 { 1661 struct ip *ip = mtod(m, struct ip *); 1662 struct in_ifaddr *ia = NULL; 1663 int error, type = 0, code = 0; 1664 struct mbuf *mcopy; 1665 struct in_addr dest; 1666 struct ifnet *destifp, dummyifp; 1667 1668 #ifdef DIAGNOSTIC 1669 if (ipprintfs) 1670 printf("forward: src %lx dst %lx ttl %x\n", 1671 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1672 ip->ip_ttl); 1673 #endif 1674 1675 1676 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1677 ipstat.ips_cantforward++; 1678 m_freem(m); 1679 return; 1680 } 1681 #ifdef IPSTEALTH 1682 if (!ipstealth) { 1683 #endif 1684 if (ip->ip_ttl <= IPTTLDEC) { 1685 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1686 0, 0); 1687 return; 1688 } 1689 #ifdef IPSTEALTH 1690 } 1691 #endif 1692 1693 if (!srcrt && (ia = ip_rtaddr(ip->ip_dst)) == NULL) { 1694 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1695 return; 1696 } 1697 1698 /* 1699 * Save the IP header and at most 8 bytes of the payload, 1700 * in case we need to generate an ICMP message to the src. 1701 * 1702 * XXX this can be optimized a lot by saving the data in a local 1703 * buffer on the stack (72 bytes at most), and only allocating the 1704 * mbuf if really necessary. The vast majority of the packets 1705 * are forwarded without having to send an ICMP back (either 1706 * because unnecessary, or because rate limited), so we are 1707 * really we are wasting a lot of work here. 1708 * 1709 * We don't use m_copy() because it might return a reference 1710 * to a shared cluster. Both this function and ip_output() 1711 * assume exclusive access to the IP header in `m', so any 1712 * data in a cluster may change before we reach icmp_error(). 1713 */ 1714 MGET(mcopy, M_DONTWAIT, m->m_type); 1715 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1716 /* 1717 * It's probably ok if the pkthdr dup fails (because 1718 * the deep copy of the tag chain failed), but for now 1719 * be conservative and just discard the copy since 1720 * code below may some day want the tags. 1721 */ 1722 m_free(mcopy); 1723 mcopy = NULL; 1724 } 1725 if (mcopy != NULL) { 1726 mcopy->m_len = imin((ip->ip_hl << 2) + 8, 1727 (int)ip->ip_len); 1728 mcopy->m_pkthdr.len = mcopy->m_len; 1729 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1730 } 1731 1732 #ifdef IPSTEALTH 1733 if (!ipstealth) { 1734 #endif 1735 ip->ip_ttl -= IPTTLDEC; 1736 #ifdef IPSTEALTH 1737 } 1738 #endif 1739 1740 /* 1741 * If forwarding packet using same interface that it came in on, 1742 * perhaps should send a redirect to sender to shortcut a hop. 1743 * Only send redirect if source is sending directly to us, 1744 * and if packet was not source routed (or has any options). 1745 * Also, don't send redirect if forwarding using a default route 1746 * or a route modified by a redirect. 1747 */ 1748 dest.s_addr = 0; 1749 if (!srcrt && ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1750 struct sockaddr_in *sin; 1751 struct route ro; 1752 struct rtentry *rt; 1753 1754 bzero(&ro, sizeof(ro)); 1755 sin = (struct sockaddr_in *)&ro.ro_dst; 1756 sin->sin_family = AF_INET; 1757 sin->sin_len = sizeof(*sin); 1758 sin->sin_addr = ip->ip_dst; 1759 rtalloc_ign(&ro, RTF_CLONING); 1760 1761 rt = ro.ro_rt; 1762 1763 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1764 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1765 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1766 u_long src = ntohl(ip->ip_src.s_addr); 1767 1768 if (RTA(rt) && 1769 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1770 if (rt->rt_flags & RTF_GATEWAY) 1771 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1772 else 1773 dest.s_addr = ip->ip_dst.s_addr; 1774 /* Router requirements says to only send host redirects */ 1775 type = ICMP_REDIRECT; 1776 code = ICMP_REDIRECT_HOST; 1777 #ifdef DIAGNOSTIC 1778 if (ipprintfs) 1779 printf("redirect (%d) to %lx\n", code, (u_long)dest.s_addr); 1780 #endif 1781 } 1782 } 1783 if (rt) 1784 RTFREE(rt); 1785 } 1786 1787 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 1788 if (error) 1789 ipstat.ips_cantforward++; 1790 else { 1791 ipstat.ips_forward++; 1792 if (type) 1793 ipstat.ips_redirectsent++; 1794 else { 1795 if (mcopy) 1796 m_freem(mcopy); 1797 return; 1798 } 1799 } 1800 if (mcopy == NULL) 1801 return; 1802 destifp = NULL; 1803 1804 switch (error) { 1805 1806 case 0: /* forwarded, but need redirect */ 1807 /* type, code set above */ 1808 break; 1809 1810 case ENETUNREACH: /* shouldn't happen, checked above */ 1811 case EHOSTUNREACH: 1812 case ENETDOWN: 1813 case EHOSTDOWN: 1814 default: 1815 type = ICMP_UNREACH; 1816 code = ICMP_UNREACH_HOST; 1817 break; 1818 1819 case EMSGSIZE: 1820 type = ICMP_UNREACH; 1821 code = ICMP_UNREACH_NEEDFRAG; 1822 #if defined(IPSEC) || defined(FAST_IPSEC) 1823 /* 1824 * If the packet is routed over IPsec tunnel, tell the 1825 * originator the tunnel MTU. 1826 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1827 * XXX quickhack!!! 1828 */ 1829 { 1830 struct secpolicy *sp = NULL; 1831 int ipsecerror; 1832 int ipsechdr; 1833 struct route *ro; 1834 1835 #ifdef IPSEC 1836 sp = ipsec4_getpolicybyaddr(mcopy, 1837 IPSEC_DIR_OUTBOUND, 1838 IP_FORWARDING, 1839 &ipsecerror); 1840 #else /* FAST_IPSEC */ 1841 sp = ipsec_getpolicybyaddr(mcopy, 1842 IPSEC_DIR_OUTBOUND, 1843 IP_FORWARDING, 1844 &ipsecerror); 1845 #endif 1846 if (sp != NULL) { 1847 /* count IPsec header size */ 1848 ipsechdr = ipsec4_hdrsiz(mcopy, 1849 IPSEC_DIR_OUTBOUND, 1850 NULL); 1851 1852 /* 1853 * find the correct route for outer IPv4 1854 * header, compute tunnel MTU. 1855 * 1856 * XXX BUG ALERT 1857 * The "dummyifp" code relies upon the fact 1858 * that icmp_error() touches only ifp->if_mtu. 1859 */ 1860 /*XXX*/ 1861 destifp = NULL; 1862 if (sp->req != NULL 1863 && sp->req->sav != NULL 1864 && sp->req->sav->sah != NULL) { 1865 ro = &sp->req->sav->sah->sa_route; 1866 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1867 dummyifp.if_mtu = 1868 ro->ro_rt->rt_rmx.rmx_mtu ? 1869 ro->ro_rt->rt_rmx.rmx_mtu : 1870 ro->ro_rt->rt_ifp->if_mtu; 1871 dummyifp.if_mtu -= ipsechdr; 1872 destifp = &dummyifp; 1873 } 1874 } 1875 1876 #ifdef IPSEC 1877 key_freesp(sp); 1878 #else /* FAST_IPSEC */ 1879 KEY_FREESP(&sp); 1880 #endif 1881 ipstat.ips_cantfrag++; 1882 break; 1883 } else 1884 #endif /*IPSEC || FAST_IPSEC*/ 1885 /* 1886 * When doing source routing 'ia' can be NULL. Fall back 1887 * to the minimum guaranteed routeable packet size and use 1888 * the same hack as IPSEC to setup a dummyifp for icmp. 1889 */ 1890 if (ia == NULL) { 1891 dummyifp.if_mtu = IP_MSS; 1892 destifp = &dummyifp; 1893 } else 1894 destifp = ia->ia_ifp; 1895 #if defined(IPSEC) || defined(FAST_IPSEC) 1896 } 1897 #endif /*IPSEC || FAST_IPSEC*/ 1898 ipstat.ips_cantfrag++; 1899 break; 1900 1901 case ENOBUFS: 1902 /* 1903 * A router should not generate ICMP_SOURCEQUENCH as 1904 * required in RFC1812 Requirements for IP Version 4 Routers. 1905 * Source quench could be a big problem under DoS attacks, 1906 * or if the underlying interface is rate-limited. 1907 * Those who need source quench packets may re-enable them 1908 * via the net.inet.ip.sendsourcequench sysctl. 1909 */ 1910 if (ip_sendsourcequench == 0) { 1911 m_freem(mcopy); 1912 return; 1913 } else { 1914 type = ICMP_SOURCEQUENCH; 1915 code = 0; 1916 } 1917 break; 1918 1919 case EACCES: /* ipfw denied packet */ 1920 m_freem(mcopy); 1921 return; 1922 } 1923 icmp_error(mcopy, type, code, dest.s_addr, destifp); 1924 } 1925 1926 void 1927 ip_savecontrol(inp, mp, ip, m) 1928 register struct inpcb *inp; 1929 register struct mbuf **mp; 1930 register struct ip *ip; 1931 register struct mbuf *m; 1932 { 1933 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1934 struct bintime bt; 1935 1936 bintime(&bt); 1937 if (inp->inp_socket->so_options & SO_BINTIME) { 1938 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 1939 SCM_BINTIME, SOL_SOCKET); 1940 if (*mp) 1941 mp = &(*mp)->m_next; 1942 } 1943 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1944 struct timeval tv; 1945 1946 bintime2timeval(&bt, &tv); 1947 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1948 SCM_TIMESTAMP, SOL_SOCKET); 1949 if (*mp) 1950 mp = &(*mp)->m_next; 1951 } 1952 } 1953 if (inp->inp_flags & INP_RECVDSTADDR) { 1954 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1955 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1956 if (*mp) 1957 mp = &(*mp)->m_next; 1958 } 1959 if (inp->inp_flags & INP_RECVTTL) { 1960 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1961 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1962 if (*mp) 1963 mp = &(*mp)->m_next; 1964 } 1965 #ifdef notyet 1966 /* XXX 1967 * Moving these out of udp_input() made them even more broken 1968 * than they already were. 1969 */ 1970 /* options were tossed already */ 1971 if (inp->inp_flags & INP_RECVOPTS) { 1972 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1973 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1974 if (*mp) 1975 mp = &(*mp)->m_next; 1976 } 1977 /* ip_srcroute doesn't do what we want here, need to fix */ 1978 if (inp->inp_flags & INP_RECVRETOPTS) { 1979 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1980 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1981 if (*mp) 1982 mp = &(*mp)->m_next; 1983 } 1984 #endif 1985 if (inp->inp_flags & INP_RECVIF) { 1986 struct ifnet *ifp; 1987 struct sdlbuf { 1988 struct sockaddr_dl sdl; 1989 u_char pad[32]; 1990 } sdlbuf; 1991 struct sockaddr_dl *sdp; 1992 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1993 1994 if (((ifp = m->m_pkthdr.rcvif)) 1995 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1996 sdp = (struct sockaddr_dl *) 1997 (ifaddr_byindex(ifp->if_index)->ifa_addr); 1998 /* 1999 * Change our mind and don't try copy. 2000 */ 2001 if ((sdp->sdl_family != AF_LINK) 2002 || (sdp->sdl_len > sizeof(sdlbuf))) { 2003 goto makedummy; 2004 } 2005 bcopy(sdp, sdl2, sdp->sdl_len); 2006 } else { 2007 makedummy: 2008 sdl2->sdl_len 2009 = offsetof(struct sockaddr_dl, sdl_data[0]); 2010 sdl2->sdl_family = AF_LINK; 2011 sdl2->sdl_index = 0; 2012 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2013 } 2014 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2015 IP_RECVIF, IPPROTO_IP); 2016 if (*mp) 2017 mp = &(*mp)->m_next; 2018 } 2019 } 2020 2021 /* 2022 * XXX these routines are called from the upper part of the kernel. 2023 * They need to be locked when we remove Giant. 2024 * 2025 * They could also be moved to ip_mroute.c, since all the RSVP 2026 * handling is done there already. 2027 */ 2028 static int ip_rsvp_on; 2029 struct socket *ip_rsvpd; 2030 int 2031 ip_rsvp_init(struct socket *so) 2032 { 2033 if (so->so_type != SOCK_RAW || 2034 so->so_proto->pr_protocol != IPPROTO_RSVP) 2035 return EOPNOTSUPP; 2036 2037 if (ip_rsvpd != NULL) 2038 return EADDRINUSE; 2039 2040 ip_rsvpd = so; 2041 /* 2042 * This may seem silly, but we need to be sure we don't over-increment 2043 * the RSVP counter, in case something slips up. 2044 */ 2045 if (!ip_rsvp_on) { 2046 ip_rsvp_on = 1; 2047 rsvp_on++; 2048 } 2049 2050 return 0; 2051 } 2052 2053 int 2054 ip_rsvp_done(void) 2055 { 2056 ip_rsvpd = NULL; 2057 /* 2058 * This may seem silly, but we need to be sure we don't over-decrement 2059 * the RSVP counter, in case something slips up. 2060 */ 2061 if (ip_rsvp_on) { 2062 ip_rsvp_on = 0; 2063 rsvp_on--; 2064 } 2065 return 0; 2066 } 2067 2068 void 2069 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 2070 { 2071 if (rsvp_input_p) { /* call the real one if loaded */ 2072 rsvp_input_p(m, off); 2073 return; 2074 } 2075 2076 /* Can still get packets with rsvp_on = 0 if there is a local member 2077 * of the group to which the RSVP packet is addressed. But in this 2078 * case we want to throw the packet away. 2079 */ 2080 2081 if (!rsvp_on) { 2082 m_freem(m); 2083 return; 2084 } 2085 2086 if (ip_rsvpd != NULL) { 2087 rip_input(m, off); 2088 return; 2089 } 2090 /* Drop the packet */ 2091 m_freem(m); 2092 }
Cache object: 67238427b45fbf95507153e0efdceaec
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