ip_input.c revision 112985
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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 34 * $FreeBSD: head/sys/netinet/ip_input.c 112985 2003-04-02 20:14:44Z mdodd $ 35 */ 36 37#include "opt_bootp.h" 38#include "opt_ipfw.h" 39#include "opt_ipdn.h" 40#include "opt_ipdivert.h" 41#include "opt_ipfilter.h" 42#include "opt_ipstealth.h" 43#include "opt_ipsec.h" 44#include "opt_mac.h" 45#include "opt_pfil_hooks.h" 46#include "opt_random_ip_id.h" 47 48#include <sys/param.h> 49#include <sys/systm.h> 50#include <sys/mac.h> 51#include <sys/mbuf.h> 52#include <sys/malloc.h> 53#include <sys/domain.h> 54#include <sys/protosw.h> 55#include <sys/socket.h> 56#include <sys/time.h> 57#include <sys/kernel.h> 58#include <sys/syslog.h> 59#include <sys/sysctl.h> 60 61#include <net/pfil.h> 62#include <net/if.h> 63#include <net/if_types.h> 64#include <net/if_var.h> 65#include <net/if_dl.h> 66#include <net/route.h> 67#include <net/netisr.h> 68 69#include <netinet/in.h> 70#include <netinet/in_systm.h> 71#include <netinet/in_var.h> 72#include <netinet/ip.h> 73#include <netinet/in_pcb.h> 74#include <netinet/ip_var.h> 75#include <netinet/ip_icmp.h> 76#include <machine/in_cksum.h> 77 78#include <sys/socketvar.h> 79 80#include <netinet/ip_fw.h> 81#include <netinet/ip_dummynet.h> 82 83#ifdef IPSEC 84#include <netinet6/ipsec.h> 85#include <netkey/key.h> 86#endif 87 88#ifdef FAST_IPSEC 89#include <netipsec/ipsec.h> 90#include <netipsec/key.h> 91#endif 92 93int rsvp_on = 0; 94 95int ipforwarding = 0; 96SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 97 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 98 99static int ipsendredirects = 1; /* XXX */ 100SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 101 &ipsendredirects, 0, "Enable sending IP redirects"); 102 103int ip_defttl = IPDEFTTL; 104SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 105 &ip_defttl, 0, "Maximum TTL on IP packets"); 106 107static int ip_dosourceroute = 0; 108SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 109 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 110 111static int ip_acceptsourceroute = 0; 112SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 113 CTLFLAG_RW, &ip_acceptsourceroute, 0, 114 "Enable accepting source routed IP packets"); 115 116static int ip_keepfaith = 0; 117SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 118 &ip_keepfaith, 0, 119 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 120 121static int nipq = 0; /* total # of reass queues */ 122static int maxnipq; 123SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 124 &maxnipq, 0, 125 "Maximum number of IPv4 fragment reassembly queue entries"); 126 127static int maxfragsperpacket; 128SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 129 &maxfragsperpacket, 0, 130 "Maximum number of IPv4 fragments allowed per packet"); 131 132static int ip_sendsourcequench = 0; 133SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 134 &ip_sendsourcequench, 0, 135 "Enable the transmission of source quench packets"); 136 137/* 138 * XXX - Setting ip_checkinterface mostly implements the receive side of 139 * the Strong ES model described in RFC 1122, but since the routing table 140 * and transmit implementation do not implement the Strong ES model, 141 * setting this to 1 results in an odd hybrid. 142 * 143 * XXX - ip_checkinterface currently must be disabled if you use ipnat 144 * to translate the destination address to another local interface. 145 * 146 * XXX - ip_checkinterface must be disabled if you add IP aliases 147 * to the loopback interface instead of the interface where the 148 * packets for those addresses are received. 149 */ 150static int ip_checkinterface = 1; 151SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 152 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 153 154#ifdef DIAGNOSTIC 155static int ipprintfs = 0; 156#endif 157 158static struct ifqueue ipintrq; 159static int ipqmaxlen = IFQ_MAXLEN; 160 161extern struct domain inetdomain; 162extern struct protosw inetsw[]; 163u_char ip_protox[IPPROTO_MAX]; 164struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 165struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 166u_long in_ifaddrhmask; /* mask for hash table */ 167 168SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 169 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 170SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 171 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 172 173struct ipstat ipstat; 174SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 175 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 176 177/* Packet reassembly stuff */ 178#define IPREASS_NHASH_LOG2 6 179#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 180#define IPREASS_HMASK (IPREASS_NHASH - 1) 181#define IPREASS_HASH(x,y) \ 182 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 183 184static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 185 186#ifdef IPCTL_DEFMTU 187SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 188 &ip_mtu, 0, "Default MTU"); 189#endif 190 191#ifdef IPSTEALTH 192static int ipstealth = 0; 193SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 194 &ipstealth, 0, ""); 195#endif 196 197 198/* Firewall hooks */ 199ip_fw_chk_t *ip_fw_chk_ptr; 200int fw_enable = 1 ; 201int fw_one_pass = 1; 202 203/* Dummynet hooks */ 204ip_dn_io_t *ip_dn_io_ptr; 205 206 207/* 208 * XXX this is ugly -- the following two global variables are 209 * used to store packet state while it travels through the stack. 210 * Note that the code even makes assumptions on the size and 211 * alignment of fields inside struct ip_srcrt so e.g. adding some 212 * fields will break the code. This needs to be fixed. 213 * 214 * We need to save the IP options in case a protocol wants to respond 215 * to an incoming packet over the same route if the packet got here 216 * using IP source routing. This allows connection establishment and 217 * maintenance when the remote end is on a network that is not known 218 * to us. 219 */ 220static int ip_nhops = 0; 221static struct ip_srcrt { 222 struct in_addr dst; /* final destination */ 223 char nop; /* one NOP to align */ 224 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 225 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 226} ip_srcrt; 227 228static void save_rte(u_char *, struct in_addr); 229static int ip_dooptions(struct mbuf *m, int, 230 struct sockaddr_in *next_hop); 231static void ip_forward(struct mbuf *m, int srcrt, 232 struct sockaddr_in *next_hop); 233static void ip_freef(struct ipqhead *, struct ipq *); 234static struct mbuf *ip_reass(struct mbuf *, struct ipqhead *, 235 struct ipq *, u_int32_t *, u_int16_t *); 236 237/* 238 * IP initialization: fill in IP protocol switch table. 239 * All protocols not implemented in kernel go to raw IP protocol handler. 240 */ 241void 242ip_init() 243{ 244 register struct protosw *pr; 245 register int i; 246 247 TAILQ_INIT(&in_ifaddrhead); 248 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 249 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 250 if (pr == 0) 251 panic("ip_init"); 252 for (i = 0; i < IPPROTO_MAX; i++) 253 ip_protox[i] = pr - inetsw; 254 for (pr = inetdomain.dom_protosw; 255 pr < inetdomain.dom_protoswNPROTOSW; pr++) 256 if (pr->pr_domain->dom_family == PF_INET && 257 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 258 ip_protox[pr->pr_protocol] = pr - inetsw; 259 260 for (i = 0; i < IPREASS_NHASH; i++) 261 TAILQ_INIT(&ipq[i]); 262 263 maxnipq = nmbclusters / 32; 264 maxfragsperpacket = 16; 265 266#ifndef RANDOM_IP_ID 267 ip_id = time_second & 0xffff; 268#endif 269 ipintrq.ifq_maxlen = ipqmaxlen; 270 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 271 netisr_register(NETISR_IP, ip_input, &ipintrq); 272} 273 274/* 275 * XXX watch out this one. It is perhaps used as a cache for 276 * the most recently used route ? it is cleared in in_addroute() 277 * when a new route is successfully created. 278 */ 279struct route ipforward_rt; 280 281/* 282 * Ip input routine. Checksum and byte swap header. If fragmented 283 * try to reassemble. Process options. Pass to next level. 284 */ 285void 286ip_input(struct mbuf *m) 287{ 288 struct ip *ip; 289 struct ipq *fp; 290 struct in_ifaddr *ia = NULL; 291 struct ifaddr *ifa; 292 int i, hlen, checkif; 293 u_short sum; 294 struct in_addr pkt_dst; 295 u_int32_t divert_info = 0; /* packet divert/tee info */ 296 struct ip_fw_args args; 297#ifdef PFIL_HOOKS 298 struct packet_filter_hook *pfh; 299 struct mbuf *m0; 300 int rv; 301#endif /* PFIL_HOOKS */ 302#ifdef FAST_IPSEC 303 struct m_tag *mtag; 304 struct tdb_ident *tdbi; 305 struct secpolicy *sp; 306 int s, error; 307#endif /* FAST_IPSEC */ 308 309 args.eh = NULL; 310 args.oif = NULL; 311 args.rule = NULL; 312 args.divert_rule = 0; /* divert cookie */ 313 args.next_hop = NULL; 314 315 /* Grab info from MT_TAG mbufs prepended to the chain. */ 316 for (; m && m->m_type == MT_TAG; m = m->m_next) { 317 switch(m->_m_tag_id) { 318 default: 319 printf("ip_input: unrecognised MT_TAG tag %d\n", 320 m->_m_tag_id); 321 break; 322 323 case PACKET_TAG_DUMMYNET: 324 args.rule = ((struct dn_pkt *)m)->rule; 325 break; 326 327 case PACKET_TAG_DIVERT: 328 args.divert_rule = (intptr_t)m->m_hdr.mh_data & 0xffff; 329 break; 330 331 case PACKET_TAG_IPFORWARD: 332 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 333 break; 334 } 335 } 336 337 KASSERT(m != NULL && (m->m_flags & M_PKTHDR) != 0, 338 ("ip_input: no HDR")); 339 340 if (args.rule) { /* dummynet already filtered us */ 341 ip = mtod(m, struct ip *); 342 hlen = ip->ip_hl << 2; 343 goto iphack ; 344 } 345 346 ipstat.ips_total++; 347 348 if (m->m_pkthdr.len < sizeof(struct ip)) 349 goto tooshort; 350 351 if (m->m_len < sizeof (struct ip) && 352 (m = m_pullup(m, sizeof (struct ip))) == 0) { 353 ipstat.ips_toosmall++; 354 return; 355 } 356 ip = mtod(m, struct ip *); 357 358 if (ip->ip_v != IPVERSION) { 359 ipstat.ips_badvers++; 360 goto bad; 361 } 362 363 hlen = ip->ip_hl << 2; 364 if (hlen < sizeof(struct ip)) { /* minimum header length */ 365 ipstat.ips_badhlen++; 366 goto bad; 367 } 368 if (hlen > m->m_len) { 369 if ((m = m_pullup(m, hlen)) == 0) { 370 ipstat.ips_badhlen++; 371 return; 372 } 373 ip = mtod(m, struct ip *); 374 } 375 376 /* 127/8 must not appear on wire - RFC1122 */ 377 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 378 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 379 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 380 ipstat.ips_badaddr++; 381 goto bad; 382 } 383 } 384 385 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 386 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 387 } else { 388 if (hlen == sizeof(struct ip)) { 389 sum = in_cksum_hdr(ip); 390 } else { 391 sum = in_cksum(m, hlen); 392 } 393 } 394 if (sum) { 395 ipstat.ips_badsum++; 396 goto bad; 397 } 398 399 /* 400 * Convert fields to host representation. 401 */ 402 ip->ip_len = ntohs(ip->ip_len); 403 if (ip->ip_len < hlen) { 404 ipstat.ips_badlen++; 405 goto bad; 406 } 407 ip->ip_off = ntohs(ip->ip_off); 408 409 /* 410 * Check that the amount of data in the buffers 411 * is as at least much as the IP header would have us expect. 412 * Trim mbufs if longer than we expect. 413 * Drop packet if shorter than we expect. 414 */ 415 if (m->m_pkthdr.len < ip->ip_len) { 416tooshort: 417 ipstat.ips_tooshort++; 418 goto bad; 419 } 420 if (m->m_pkthdr.len > ip->ip_len) { 421 if (m->m_len == m->m_pkthdr.len) { 422 m->m_len = ip->ip_len; 423 m->m_pkthdr.len = ip->ip_len; 424 } else 425 m_adj(m, ip->ip_len - m->m_pkthdr.len); 426 } 427#if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 428 /* 429 * Bypass packet filtering for packets from a tunnel (gif). 430 */ 431 if (ipsec_gethist(m, NULL)) 432 goto pass; 433#endif 434 435 /* 436 * IpHack's section. 437 * Right now when no processing on packet has done 438 * and it is still fresh out of network we do our black 439 * deals with it. 440 * - Firewall: deny/allow/divert 441 * - Xlate: translate packet's addr/port (NAT). 442 * - Pipe: pass pkt through dummynet. 443 * - Wrap: fake packet's addr/port <unimpl.> 444 * - Encapsulate: put it in another IP and send out. <unimp.> 445 */ 446 447iphack: 448 449#ifdef PFIL_HOOKS 450 /* 451 * Run through list of hooks for input packets. If there are any 452 * filters which require that additional packets in the flow are 453 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 454 * Note that filters must _never_ set this flag, as another filter 455 * in the list may have previously cleared it. 456 */ 457 m0 = m; 458 pfh = pfil_hook_get(PFIL_IN, &inetsw[ip_protox[IPPROTO_IP]].pr_pfh); 459 for (; pfh; pfh = TAILQ_NEXT(pfh, pfil_link)) 460 if (pfh->pfil_func) { 461 rv = pfh->pfil_func(ip, hlen, 462 m->m_pkthdr.rcvif, 0, &m0); 463 if (rv) 464 return; 465 m = m0; 466 if (m == NULL) 467 return; 468 ip = mtod(m, struct ip *); 469 } 470#endif /* PFIL_HOOKS */ 471 472 if (fw_enable && IPFW_LOADED) { 473 /* 474 * If we've been forwarded from the output side, then 475 * skip the firewall a second time 476 */ 477 if (args.next_hop) 478 goto ours; 479 480 args.m = m; 481 i = ip_fw_chk_ptr(&args); 482 m = args.m; 483 484 if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 485 if (m) 486 m_freem(m); 487 return; 488 } 489 ip = mtod(m, struct ip *); /* just in case m changed */ 490 if (i == 0 && args.next_hop == NULL) /* common case */ 491 goto pass; 492 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) { 493 /* Send packet to the appropriate pipe */ 494 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 495 return; 496 } 497#ifdef IPDIVERT 498 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 499 /* Divert or tee packet */ 500 divert_info = i; 501 goto ours; 502 } 503#endif 504 if (i == 0 && args.next_hop != NULL) 505 goto pass; 506 /* 507 * if we get here, the packet must be dropped 508 */ 509 m_freem(m); 510 return; 511 } 512pass: 513 514 /* 515 * Process options and, if not destined for us, 516 * ship it on. ip_dooptions returns 1 when an 517 * error was detected (causing an icmp message 518 * to be sent and the original packet to be freed). 519 */ 520 ip_nhops = 0; /* for source routed packets */ 521 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, args.next_hop)) 522 return; 523 524 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 525 * matter if it is destined to another node, or whether it is 526 * a multicast one, RSVP wants it! and prevents it from being forwarded 527 * anywhere else. Also checks if the rsvp daemon is running before 528 * grabbing the packet. 529 */ 530 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 531 goto ours; 532 533 /* 534 * Check our list of addresses, to see if the packet is for us. 535 * If we don't have any addresses, assume any unicast packet 536 * we receive might be for us (and let the upper layers deal 537 * with it). 538 */ 539 if (TAILQ_EMPTY(&in_ifaddrhead) && 540 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 541 goto ours; 542 543 /* 544 * Cache the destination address of the packet; this may be 545 * changed by use of 'ipfw fwd'. 546 */ 547 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 548 549 /* 550 * Enable a consistency check between the destination address 551 * and the arrival interface for a unicast packet (the RFC 1122 552 * strong ES model) if IP forwarding is disabled and the packet 553 * is not locally generated and the packet is not subject to 554 * 'ipfw fwd'. 555 * 556 * XXX - Checking also should be disabled if the destination 557 * address is ipnat'ed to a different interface. 558 * 559 * XXX - Checking is incompatible with IP aliases added 560 * to the loopback interface instead of the interface where 561 * the packets are received. 562 */ 563 checkif = ip_checkinterface && (ipforwarding == 0) && 564 m->m_pkthdr.rcvif != NULL && 565 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 566 (args.next_hop == NULL); 567 568 /* 569 * Check for exact addresses in the hash bucket. 570 */ 571 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 572 /* 573 * If the address matches, verify that the packet 574 * arrived via the correct interface if checking is 575 * enabled. 576 */ 577 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 578 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 579 goto ours; 580 } 581 /* 582 * Check for broadcast addresses. 583 * 584 * Only accept broadcast packets that arrive via the matching 585 * interface. Reception of forwarded directed broadcasts would 586 * be handled via ip_forward() and ether_output() with the loopback 587 * into the stack for SIMPLEX interfaces handled by ether_output(). 588 */ 589 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 590 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 591 if (ifa->ifa_addr->sa_family != AF_INET) 592 continue; 593 ia = ifatoia(ifa); 594 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 595 pkt_dst.s_addr) 596 goto ours; 597 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 598 goto ours; 599#ifdef BOOTP_COMPAT 600 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 601 goto ours; 602#endif 603 } 604 } 605 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 606 struct in_multi *inm; 607 if (ip_mrouter) { 608 /* 609 * If we are acting as a multicast router, all 610 * incoming multicast packets are passed to the 611 * kernel-level multicast forwarding function. 612 * The packet is returned (relatively) intact; if 613 * ip_mforward() returns a non-zero value, the packet 614 * must be discarded, else it may be accepted below. 615 */ 616 if (ip_mforward && 617 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 618 ipstat.ips_cantforward++; 619 m_freem(m); 620 return; 621 } 622 623 /* 624 * The process-level routing daemon needs to receive 625 * all multicast IGMP packets, whether or not this 626 * host belongs to their destination groups. 627 */ 628 if (ip->ip_p == IPPROTO_IGMP) 629 goto ours; 630 ipstat.ips_forward++; 631 } 632 /* 633 * See if we belong to the destination multicast group on the 634 * arrival interface. 635 */ 636 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 637 if (inm == NULL) { 638 ipstat.ips_notmember++; 639 m_freem(m); 640 return; 641 } 642 goto ours; 643 } 644 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 645 goto ours; 646 if (ip->ip_dst.s_addr == INADDR_ANY) 647 goto ours; 648 649 /* 650 * FAITH(Firewall Aided Internet Translator) 651 */ 652 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 653 if (ip_keepfaith) { 654 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 655 goto ours; 656 } 657 m_freem(m); 658 return; 659 } 660 661 /* 662 * Not for us; forward if possible and desirable. 663 */ 664 if (ipforwarding == 0) { 665 ipstat.ips_cantforward++; 666 m_freem(m); 667 } else { 668#ifdef IPSEC 669 /* 670 * Enforce inbound IPsec SPD. 671 */ 672 if (ipsec4_in_reject(m, NULL)) { 673 ipsecstat.in_polvio++; 674 goto bad; 675 } 676#endif /* IPSEC */ 677#ifdef FAST_IPSEC 678 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 679 s = splnet(); 680 if (mtag != NULL) { 681 tdbi = (struct tdb_ident *)(mtag + 1); 682 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 683 } else { 684 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 685 IP_FORWARDING, &error); 686 } 687 if (sp == NULL) { /* NB: can happen if error */ 688 splx(s); 689 /*XXX error stat???*/ 690 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 691 goto bad; 692 } 693 694 /* 695 * Check security policy against packet attributes. 696 */ 697 error = ipsec_in_reject(sp, m); 698 KEY_FREESP(&sp); 699 splx(s); 700 if (error) { 701 ipstat.ips_cantforward++; 702 goto bad; 703 } 704#endif /* FAST_IPSEC */ 705 ip_forward(m, 0, args.next_hop); 706 } 707 return; 708 709ours: 710#ifdef IPSTEALTH 711 /* 712 * IPSTEALTH: Process non-routing options only 713 * if the packet is destined for us. 714 */ 715 if (ipstealth && hlen > sizeof (struct ip) && 716 ip_dooptions(m, 1, args.next_hop)) 717 return; 718#endif /* IPSTEALTH */ 719 720 /* Count the packet in the ip address stats */ 721 if (ia != NULL) { 722 ia->ia_ifa.if_ipackets++; 723 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 724 } 725 726 /* 727 * If offset or IP_MF are set, must reassemble. 728 * Otherwise, nothing need be done. 729 * (We could look in the reassembly queue to see 730 * if the packet was previously fragmented, 731 * but it's not worth the time; just let them time out.) 732 */ 733 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 734 735 /* If maxnipq is 0, never accept fragments. */ 736 if (maxnipq == 0) { 737 ipstat.ips_fragments++; 738 ipstat.ips_fragdropped++; 739 goto bad; 740 } 741 742 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 743 /* 744 * Look for queue of fragments 745 * of this datagram. 746 */ 747 TAILQ_FOREACH(fp, &ipq[sum], ipq_list) 748 if (ip->ip_id == fp->ipq_id && 749 ip->ip_src.s_addr == fp->ipq_src.s_addr && 750 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 751#ifdef MAC 752 mac_fragment_match(m, fp) && 753#endif 754 ip->ip_p == fp->ipq_p) 755 goto found; 756 757 fp = 0; 758 759 /* 760 * Enforce upper bound on number of fragmented packets 761 * for which we attempt reassembly; 762 * If maxnipq is -1, accept all fragments without limitation. 763 */ 764 if ((nipq > maxnipq) && (maxnipq > 0)) { 765 /* 766 * drop something from the tail of the current queue 767 * before proceeding further 768 */ 769 struct ipq *q = TAILQ_LAST(&ipq[sum], ipqhead); 770 if (q == NULL) { /* gak */ 771 for (i = 0; i < IPREASS_NHASH; i++) { 772 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 773 if (r) { 774 ipstat.ips_fragtimeout += r->ipq_nfrags; 775 ip_freef(&ipq[i], r); 776 break; 777 } 778 } 779 } else { 780 ipstat.ips_fragtimeout += q->ipq_nfrags; 781 ip_freef(&ipq[sum], q); 782 } 783 } 784found: 785 /* 786 * Adjust ip_len to not reflect header, 787 * convert offset of this to bytes. 788 */ 789 ip->ip_len -= hlen; 790 if (ip->ip_off & IP_MF) { 791 /* 792 * Make sure that fragments have a data length 793 * that's a non-zero multiple of 8 bytes. 794 */ 795 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 796 ipstat.ips_toosmall++; /* XXX */ 797 goto bad; 798 } 799 m->m_flags |= M_FRAG; 800 } else 801 m->m_flags &= ~M_FRAG; 802 ip->ip_off <<= 3; 803 804 /* 805 * Attempt reassembly; if it succeeds, proceed. 806 * ip_reass() will return a different mbuf, and update 807 * the divert info in divert_info and args.divert_rule. 808 */ 809 ipstat.ips_fragments++; 810 m->m_pkthdr.header = ip; 811 m = ip_reass(m, 812 &ipq[sum], fp, &divert_info, &args.divert_rule); 813 if (m == 0) 814 return; 815 ipstat.ips_reassembled++; 816 ip = mtod(m, struct ip *); 817 /* Get the header length of the reassembled packet */ 818 hlen = ip->ip_hl << 2; 819#ifdef IPDIVERT 820 /* Restore original checksum before diverting packet */ 821 if (divert_info != 0) { 822 ip->ip_len += hlen; 823 ip->ip_len = htons(ip->ip_len); 824 ip->ip_off = htons(ip->ip_off); 825 ip->ip_sum = 0; 826 if (hlen == sizeof(struct ip)) 827 ip->ip_sum = in_cksum_hdr(ip); 828 else 829 ip->ip_sum = in_cksum(m, hlen); 830 ip->ip_off = ntohs(ip->ip_off); 831 ip->ip_len = ntohs(ip->ip_len); 832 ip->ip_len -= hlen; 833 } 834#endif 835 } else 836 ip->ip_len -= hlen; 837 838#ifdef IPDIVERT 839 /* 840 * Divert or tee packet to the divert protocol if required. 841 */ 842 if (divert_info != 0) { 843 struct mbuf *clone = NULL; 844 845 /* Clone packet if we're doing a 'tee' */ 846 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 847 clone = m_dup(m, M_DONTWAIT); 848 849 /* Restore packet header fields to original values */ 850 ip->ip_len += hlen; 851 ip->ip_len = htons(ip->ip_len); 852 ip->ip_off = htons(ip->ip_off); 853 854 /* Deliver packet to divert input routine */ 855 divert_packet(m, 1, divert_info & 0xffff, args.divert_rule); 856 ipstat.ips_delivered++; 857 858 /* If 'tee', continue with original packet */ 859 if (clone == NULL) 860 return; 861 m = clone; 862 ip = mtod(m, struct ip *); 863 ip->ip_len += hlen; 864 /* 865 * Jump backwards to complete processing of the 866 * packet. But first clear divert_info to avoid 867 * entering this block again. 868 * We do not need to clear args.divert_rule 869 * or args.next_hop as they will not be used. 870 */ 871 divert_info = 0; 872 goto pass; 873 } 874#endif 875 876#ifdef IPSEC 877 /* 878 * enforce IPsec policy checking if we are seeing last header. 879 * note that we do not visit this with protocols with pcb layer 880 * code - like udp/tcp/raw ip. 881 */ 882 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 883 ipsec4_in_reject(m, NULL)) { 884 ipsecstat.in_polvio++; 885 goto bad; 886 } 887#endif 888#if FAST_IPSEC 889 /* 890 * enforce IPsec policy checking if we are seeing last header. 891 * note that we do not visit this with protocols with pcb layer 892 * code - like udp/tcp/raw ip. 893 */ 894 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 895 /* 896 * Check if the packet has already had IPsec processing 897 * done. If so, then just pass it along. This tag gets 898 * set during AH, ESP, etc. input handling, before the 899 * packet is returned to the ip input queue for delivery. 900 */ 901 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 902 s = splnet(); 903 if (mtag != NULL) { 904 tdbi = (struct tdb_ident *)(mtag + 1); 905 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 906 } else { 907 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 908 IP_FORWARDING, &error); 909 } 910 if (sp != NULL) { 911 /* 912 * Check security policy against packet attributes. 913 */ 914 error = ipsec_in_reject(sp, m); 915 KEY_FREESP(&sp); 916 } else { 917 /* XXX error stat??? */ 918 error = EINVAL; 919DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 920 goto bad; 921 } 922 splx(s); 923 if (error) 924 goto bad; 925 } 926#endif /* FAST_IPSEC */ 927 928 /* 929 * Switch out to protocol's input routine. 930 */ 931 ipstat.ips_delivered++; 932 if (args.next_hop && ip->ip_p == IPPROTO_TCP) { 933 /* TCP needs IPFORWARD info if available */ 934 struct m_hdr tag; 935 936 tag.mh_type = MT_TAG; 937 tag.mh_flags = PACKET_TAG_IPFORWARD; 938 tag.mh_data = (caddr_t)args.next_hop; 939 tag.mh_next = m; 940 941 (*inetsw[ip_protox[ip->ip_p]].pr_input)( 942 (struct mbuf *)&tag, hlen); 943 } else 944 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 945 return; 946bad: 947 m_freem(m); 948} 949 950/* 951 * Take incoming datagram fragment and try to reassemble it into 952 * whole datagram. If a chain for reassembly of this datagram already 953 * exists, then it is given as fp; otherwise have to make a chain. 954 * 955 * When IPDIVERT enabled, keep additional state with each packet that 956 * tells us if we need to divert or tee the packet we're building. 957 * In particular, *divinfo includes the port and TEE flag, 958 * *divert_rule is the number of the matching rule. 959 */ 960 961static struct mbuf * 962ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp, 963 u_int32_t *divinfo, u_int16_t *divert_rule) 964{ 965 struct ip *ip = mtod(m, struct ip *); 966 register struct mbuf *p, *q, *nq; 967 struct mbuf *t; 968 int hlen = ip->ip_hl << 2; 969 int i, next; 970 971 /* 972 * Presence of header sizes in mbufs 973 * would confuse code below. 974 */ 975 m->m_data += hlen; 976 m->m_len -= hlen; 977 978 /* 979 * If first fragment to arrive, create a reassembly queue. 980 */ 981 if (fp == 0) { 982 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 983 goto dropfrag; 984 fp = mtod(t, struct ipq *); 985#ifdef MAC 986 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 987 m_free(t); 988 goto dropfrag; 989 } 990 mac_create_ipq(m, fp); 991#endif 992 TAILQ_INSERT_HEAD(head, fp, ipq_list); 993 nipq++; 994 fp->ipq_nfrags = 1; 995 fp->ipq_ttl = IPFRAGTTL; 996 fp->ipq_p = ip->ip_p; 997 fp->ipq_id = ip->ip_id; 998 fp->ipq_src = ip->ip_src; 999 fp->ipq_dst = ip->ip_dst; 1000 fp->ipq_frags = m; 1001 m->m_nextpkt = NULL; 1002#ifdef IPDIVERT 1003 fp->ipq_div_info = 0; 1004 fp->ipq_div_cookie = 0; 1005#endif 1006 goto inserted; 1007 } else { 1008 fp->ipq_nfrags++; 1009#ifdef MAC 1010 mac_update_ipq(m, fp); 1011#endif 1012 } 1013 1014#define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1015 1016 /* 1017 * Find a segment which begins after this one does. 1018 */ 1019 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1020 if (GETIP(q)->ip_off > ip->ip_off) 1021 break; 1022 1023 /* 1024 * If there is a preceding segment, it may provide some of 1025 * our data already. If so, drop the data from the incoming 1026 * segment. If it provides all of our data, drop us, otherwise 1027 * stick new segment in the proper place. 1028 * 1029 * If some of the data is dropped from the the preceding 1030 * segment, then it's checksum is invalidated. 1031 */ 1032 if (p) { 1033 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1034 if (i > 0) { 1035 if (i >= ip->ip_len) 1036 goto dropfrag; 1037 m_adj(m, i); 1038 m->m_pkthdr.csum_flags = 0; 1039 ip->ip_off += i; 1040 ip->ip_len -= i; 1041 } 1042 m->m_nextpkt = p->m_nextpkt; 1043 p->m_nextpkt = m; 1044 } else { 1045 m->m_nextpkt = fp->ipq_frags; 1046 fp->ipq_frags = m; 1047 } 1048 1049 /* 1050 * While we overlap succeeding segments trim them or, 1051 * if they are completely covered, dequeue them. 1052 */ 1053 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1054 q = nq) { 1055 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1056 if (i < GETIP(q)->ip_len) { 1057 GETIP(q)->ip_len -= i; 1058 GETIP(q)->ip_off += i; 1059 m_adj(q, i); 1060 q->m_pkthdr.csum_flags = 0; 1061 break; 1062 } 1063 nq = q->m_nextpkt; 1064 m->m_nextpkt = nq; 1065 ipstat.ips_fragdropped++; 1066 fp->ipq_nfrags--; 1067 m_freem(q); 1068 } 1069 1070inserted: 1071 1072#ifdef IPDIVERT 1073 /* 1074 * Transfer firewall instructions to the fragment structure. 1075 * Only trust info in the fragment at offset 0. 1076 */ 1077 if (ip->ip_off == 0) { 1078 fp->ipq_div_info = *divinfo; 1079 fp->ipq_div_cookie = *divert_rule; 1080 } 1081 *divinfo = 0; 1082 *divert_rule = 0; 1083#endif 1084 1085 /* 1086 * Check for complete reassembly and perform frag per packet 1087 * limiting. 1088 * 1089 * Frag limiting is performed here so that the nth frag has 1090 * a chance to complete the packet before we drop the packet. 1091 * As a result, n+1 frags are actually allowed per packet, but 1092 * only n will ever be stored. (n = maxfragsperpacket.) 1093 * 1094 */ 1095 next = 0; 1096 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1097 if (GETIP(q)->ip_off != next) { 1098 if (fp->ipq_nfrags > maxfragsperpacket) { 1099 ipstat.ips_fragdropped += fp->ipq_nfrags; 1100 ip_freef(head, fp); 1101 } 1102 return (0); 1103 } 1104 next += GETIP(q)->ip_len; 1105 } 1106 /* Make sure the last packet didn't have the IP_MF flag */ 1107 if (p->m_flags & M_FRAG) { 1108 if (fp->ipq_nfrags > maxfragsperpacket) { 1109 ipstat.ips_fragdropped += fp->ipq_nfrags; 1110 ip_freef(head, fp); 1111 } 1112 return (0); 1113 } 1114 1115 /* 1116 * Reassembly is complete. Make sure the packet is a sane size. 1117 */ 1118 q = fp->ipq_frags; 1119 ip = GETIP(q); 1120 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1121 ipstat.ips_toolong++; 1122 ipstat.ips_fragdropped += fp->ipq_nfrags; 1123 ip_freef(head, fp); 1124 return (0); 1125 } 1126 1127 /* 1128 * Concatenate fragments. 1129 */ 1130 m = q; 1131 t = m->m_next; 1132 m->m_next = 0; 1133 m_cat(m, t); 1134 nq = q->m_nextpkt; 1135 q->m_nextpkt = 0; 1136 for (q = nq; q != NULL; q = nq) { 1137 nq = q->m_nextpkt; 1138 q->m_nextpkt = NULL; 1139 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1140 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1141 m_cat(m, q); 1142 } 1143#ifdef MAC 1144 mac_create_datagram_from_ipq(fp, m); 1145 mac_destroy_ipq(fp); 1146#endif 1147 1148#ifdef IPDIVERT 1149 /* 1150 * Extract firewall instructions from the fragment structure. 1151 */ 1152 *divinfo = fp->ipq_div_info; 1153 *divert_rule = fp->ipq_div_cookie; 1154#endif 1155 1156 /* 1157 * Create header for new ip packet by 1158 * modifying header of first packet; 1159 * dequeue and discard fragment reassembly header. 1160 * Make header visible. 1161 */ 1162 ip->ip_len = next; 1163 ip->ip_src = fp->ipq_src; 1164 ip->ip_dst = fp->ipq_dst; 1165 TAILQ_REMOVE(head, fp, ipq_list); 1166 nipq--; 1167 (void) m_free(dtom(fp)); 1168 m->m_len += (ip->ip_hl << 2); 1169 m->m_data -= (ip->ip_hl << 2); 1170 /* some debugging cruft by sklower, below, will go away soon */ 1171 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1172 m_fixhdr(m); 1173 return (m); 1174 1175dropfrag: 1176#ifdef IPDIVERT 1177 *divinfo = 0; 1178 *divert_rule = 0; 1179#endif 1180 ipstat.ips_fragdropped++; 1181 if (fp != 0) 1182 fp->ipq_nfrags--; 1183 m_freem(m); 1184 return (0); 1185 1186#undef GETIP 1187} 1188 1189/* 1190 * Free a fragment reassembly header and all 1191 * associated datagrams. 1192 */ 1193static void 1194ip_freef(fhp, fp) 1195 struct ipqhead *fhp; 1196 struct ipq *fp; 1197{ 1198 register struct mbuf *q; 1199 1200 while (fp->ipq_frags) { 1201 q = fp->ipq_frags; 1202 fp->ipq_frags = q->m_nextpkt; 1203 m_freem(q); 1204 } 1205 TAILQ_REMOVE(fhp, fp, ipq_list); 1206 (void) m_free(dtom(fp)); 1207 nipq--; 1208} 1209 1210/* 1211 * IP timer processing; 1212 * if a timer expires on a reassembly 1213 * queue, discard it. 1214 */ 1215void 1216ip_slowtimo() 1217{ 1218 register struct ipq *fp; 1219 int s = splnet(); 1220 int i; 1221 1222 for (i = 0; i < IPREASS_NHASH; i++) { 1223 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1224 struct ipq *fpp; 1225 1226 fpp = fp; 1227 fp = TAILQ_NEXT(fp, ipq_list); 1228 if(--fpp->ipq_ttl == 0) { 1229 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1230 ip_freef(&ipq[i], fpp); 1231 } 1232 } 1233 } 1234 /* 1235 * If we are over the maximum number of fragments 1236 * (due to the limit being lowered), drain off 1237 * enough to get down to the new limit. 1238 */ 1239 if (maxnipq >= 0 && nipq > maxnipq) { 1240 for (i = 0; i < IPREASS_NHASH; i++) { 1241 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1242 ipstat.ips_fragdropped += 1243 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1244 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1245 } 1246 } 1247 } 1248 ipflow_slowtimo(); 1249 splx(s); 1250} 1251 1252/* 1253 * Drain off all datagram fragments. 1254 */ 1255void 1256ip_drain() 1257{ 1258 int i; 1259 1260 for (i = 0; i < IPREASS_NHASH; i++) { 1261 while(!TAILQ_EMPTY(&ipq[i])) { 1262 ipstat.ips_fragdropped += 1263 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1264 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1265 } 1266 } 1267 in_rtqdrain(); 1268} 1269 1270/* 1271 * Do option processing on a datagram, 1272 * possibly discarding it if bad options are encountered, 1273 * or forwarding it if source-routed. 1274 * The pass argument is used when operating in the IPSTEALTH 1275 * mode to tell what options to process: 1276 * [LS]SRR (pass 0) or the others (pass 1). 1277 * The reason for as many as two passes is that when doing IPSTEALTH, 1278 * non-routing options should be processed only if the packet is for us. 1279 * Returns 1 if packet has been forwarded/freed, 1280 * 0 if the packet should be processed further. 1281 */ 1282static int 1283ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1284{ 1285 struct ip *ip = mtod(m, struct ip *); 1286 u_char *cp; 1287 struct in_ifaddr *ia; 1288 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1289 struct in_addr *sin, dst; 1290 n_time ntime; 1291 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 1292 1293 dst = ip->ip_dst; 1294 cp = (u_char *)(ip + 1); 1295 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1296 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1297 opt = cp[IPOPT_OPTVAL]; 1298 if (opt == IPOPT_EOL) 1299 break; 1300 if (opt == IPOPT_NOP) 1301 optlen = 1; 1302 else { 1303 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1304 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1305 goto bad; 1306 } 1307 optlen = cp[IPOPT_OLEN]; 1308 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1309 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1310 goto bad; 1311 } 1312 } 1313 switch (opt) { 1314 1315 default: 1316 break; 1317 1318 /* 1319 * Source routing with record. 1320 * Find interface with current destination address. 1321 * If none on this machine then drop if strictly routed, 1322 * or do nothing if loosely routed. 1323 * Record interface address and bring up next address 1324 * component. If strictly routed make sure next 1325 * address is on directly accessible net. 1326 */ 1327 case IPOPT_LSRR: 1328 case IPOPT_SSRR: 1329#ifdef IPSTEALTH 1330 if (ipstealth && pass > 0) 1331 break; 1332#endif 1333 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1334 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1335 goto bad; 1336 } 1337 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1338 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1339 goto bad; 1340 } 1341 ipaddr.sin_addr = ip->ip_dst; 1342 ia = (struct in_ifaddr *) 1343 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1344 if (ia == 0) { 1345 if (opt == IPOPT_SSRR) { 1346 type = ICMP_UNREACH; 1347 code = ICMP_UNREACH_SRCFAIL; 1348 goto bad; 1349 } 1350 if (!ip_dosourceroute) 1351 goto nosourcerouting; 1352 /* 1353 * Loose routing, and not at next destination 1354 * yet; nothing to do except forward. 1355 */ 1356 break; 1357 } 1358 off--; /* 0 origin */ 1359 if (off > optlen - (int)sizeof(struct in_addr)) { 1360 /* 1361 * End of source route. Should be for us. 1362 */ 1363 if (!ip_acceptsourceroute) 1364 goto nosourcerouting; 1365 save_rte(cp, ip->ip_src); 1366 break; 1367 } 1368#ifdef IPSTEALTH 1369 if (ipstealth) 1370 goto dropit; 1371#endif 1372 if (!ip_dosourceroute) { 1373 if (ipforwarding) { 1374 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1375 /* 1376 * Acting as a router, so generate ICMP 1377 */ 1378nosourcerouting: 1379 strcpy(buf, inet_ntoa(ip->ip_dst)); 1380 log(LOG_WARNING, 1381 "attempted source route from %s to %s\n", 1382 inet_ntoa(ip->ip_src), buf); 1383 type = ICMP_UNREACH; 1384 code = ICMP_UNREACH_SRCFAIL; 1385 goto bad; 1386 } else { 1387 /* 1388 * Not acting as a router, so silently drop. 1389 */ 1390#ifdef IPSTEALTH 1391dropit: 1392#endif 1393 ipstat.ips_cantforward++; 1394 m_freem(m); 1395 return (1); 1396 } 1397 } 1398 1399 /* 1400 * locate outgoing interface 1401 */ 1402 (void)memcpy(&ipaddr.sin_addr, cp + off, 1403 sizeof(ipaddr.sin_addr)); 1404 1405 if (opt == IPOPT_SSRR) { 1406#define INA struct in_ifaddr * 1407#define SA struct sockaddr * 1408 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1409 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1410 } else 1411 ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt); 1412 if (ia == 0) { 1413 type = ICMP_UNREACH; 1414 code = ICMP_UNREACH_SRCFAIL; 1415 goto bad; 1416 } 1417 ip->ip_dst = ipaddr.sin_addr; 1418 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1419 sizeof(struct in_addr)); 1420 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1421 /* 1422 * Let ip_intr's mcast routing check handle mcast pkts 1423 */ 1424 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1425 break; 1426 1427 case IPOPT_RR: 1428#ifdef IPSTEALTH 1429 if (ipstealth && pass == 0) 1430 break; 1431#endif 1432 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1433 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1434 goto bad; 1435 } 1436 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1437 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1438 goto bad; 1439 } 1440 /* 1441 * If no space remains, ignore. 1442 */ 1443 off--; /* 0 origin */ 1444 if (off > optlen - (int)sizeof(struct in_addr)) 1445 break; 1446 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1447 sizeof(ipaddr.sin_addr)); 1448 /* 1449 * locate outgoing interface; if we're the destination, 1450 * use the incoming interface (should be same). 1451 */ 1452 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1453 (ia = ip_rtaddr(ipaddr.sin_addr, 1454 &ipforward_rt)) == 0) { 1455 type = ICMP_UNREACH; 1456 code = ICMP_UNREACH_HOST; 1457 goto bad; 1458 } 1459 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1460 sizeof(struct in_addr)); 1461 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1462 break; 1463 1464 case IPOPT_TS: 1465#ifdef IPSTEALTH 1466 if (ipstealth && pass == 0) 1467 break; 1468#endif 1469 code = cp - (u_char *)ip; 1470 if (optlen < 4 || optlen > 40) { 1471 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1472 goto bad; 1473 } 1474 if ((off = cp[IPOPT_OFFSET]) < 5) { 1475 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1476 goto bad; 1477 } 1478 if (off > optlen - (int)sizeof(int32_t)) { 1479 cp[IPOPT_OFFSET + 1] += (1 << 4); 1480 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1481 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1482 goto bad; 1483 } 1484 break; 1485 } 1486 off--; /* 0 origin */ 1487 sin = (struct in_addr *)(cp + off); 1488 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1489 1490 case IPOPT_TS_TSONLY: 1491 break; 1492 1493 case IPOPT_TS_TSANDADDR: 1494 if (off + sizeof(n_time) + 1495 sizeof(struct in_addr) > optlen) { 1496 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1497 goto bad; 1498 } 1499 ipaddr.sin_addr = dst; 1500 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1501 m->m_pkthdr.rcvif); 1502 if (ia == 0) 1503 continue; 1504 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1505 sizeof(struct in_addr)); 1506 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1507 off += sizeof(struct in_addr); 1508 break; 1509 1510 case IPOPT_TS_PRESPEC: 1511 if (off + sizeof(n_time) + 1512 sizeof(struct in_addr) > optlen) { 1513 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1514 goto bad; 1515 } 1516 (void)memcpy(&ipaddr.sin_addr, sin, 1517 sizeof(struct in_addr)); 1518 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1519 continue; 1520 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1521 off += sizeof(struct in_addr); 1522 break; 1523 1524 default: 1525 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1526 goto bad; 1527 } 1528 ntime = iptime(); 1529 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1530 cp[IPOPT_OFFSET] += sizeof(n_time); 1531 } 1532 } 1533 if (forward && ipforwarding) { 1534 ip_forward(m, 1, next_hop); 1535 return (1); 1536 } 1537 return (0); 1538bad: 1539 icmp_error(m, type, code, 0, 0); 1540 ipstat.ips_badoptions++; 1541 return (1); 1542} 1543 1544/* 1545 * Given address of next destination (final or next hop), 1546 * return internet address info of interface to be used to get there. 1547 */ 1548struct in_ifaddr * 1549ip_rtaddr(dst, rt) 1550 struct in_addr dst; 1551 struct route *rt; 1552{ 1553 register struct sockaddr_in *sin; 1554 1555 sin = (struct sockaddr_in *)&rt->ro_dst; 1556 1557 if (rt->ro_rt == 0 || 1558 !(rt->ro_rt->rt_flags & RTF_UP) || 1559 dst.s_addr != sin->sin_addr.s_addr) { 1560 if (rt->ro_rt) { 1561 RTFREE(rt->ro_rt); 1562 rt->ro_rt = 0; 1563 } 1564 sin->sin_family = AF_INET; 1565 sin->sin_len = sizeof(*sin); 1566 sin->sin_addr = dst; 1567 1568 rtalloc_ign(rt, RTF_PRCLONING); 1569 } 1570 if (rt->ro_rt == 0) 1571 return ((struct in_ifaddr *)0); 1572 return (ifatoia(rt->ro_rt->rt_ifa)); 1573} 1574 1575/* 1576 * Save incoming source route for use in replies, 1577 * to be picked up later by ip_srcroute if the receiver is interested. 1578 */ 1579static void 1580save_rte(option, dst) 1581 u_char *option; 1582 struct in_addr dst; 1583{ 1584 unsigned olen; 1585 1586 olen = option[IPOPT_OLEN]; 1587#ifdef DIAGNOSTIC 1588 if (ipprintfs) 1589 printf("save_rte: olen %d\n", olen); 1590#endif 1591 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1592 return; 1593 bcopy(option, ip_srcrt.srcopt, olen); 1594 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1595 ip_srcrt.dst = dst; 1596} 1597 1598/* 1599 * Retrieve incoming source route for use in replies, 1600 * in the same form used by setsockopt. 1601 * The first hop is placed before the options, will be removed later. 1602 */ 1603struct mbuf * 1604ip_srcroute() 1605{ 1606 register struct in_addr *p, *q; 1607 register struct mbuf *m; 1608 1609 if (ip_nhops == 0) 1610 return ((struct mbuf *)0); 1611 m = m_get(M_DONTWAIT, MT_HEADER); 1612 if (m == 0) 1613 return ((struct mbuf *)0); 1614 1615#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1616 1617 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1618 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1619 OPTSIZ; 1620#ifdef DIAGNOSTIC 1621 if (ipprintfs) 1622 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1623#endif 1624 1625 /* 1626 * First save first hop for return route 1627 */ 1628 p = &ip_srcrt.route[ip_nhops - 1]; 1629 *(mtod(m, struct in_addr *)) = *p--; 1630#ifdef DIAGNOSTIC 1631 if (ipprintfs) 1632 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1633#endif 1634 1635 /* 1636 * Copy option fields and padding (nop) to mbuf. 1637 */ 1638 ip_srcrt.nop = IPOPT_NOP; 1639 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1640 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1641 &ip_srcrt.nop, OPTSIZ); 1642 q = (struct in_addr *)(mtod(m, caddr_t) + 1643 sizeof(struct in_addr) + OPTSIZ); 1644#undef OPTSIZ 1645 /* 1646 * Record return path as an IP source route, 1647 * reversing the path (pointers are now aligned). 1648 */ 1649 while (p >= ip_srcrt.route) { 1650#ifdef DIAGNOSTIC 1651 if (ipprintfs) 1652 printf(" %lx", (u_long)ntohl(q->s_addr)); 1653#endif 1654 *q++ = *p--; 1655 } 1656 /* 1657 * Last hop goes to final destination. 1658 */ 1659 *q = ip_srcrt.dst; 1660#ifdef DIAGNOSTIC 1661 if (ipprintfs) 1662 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1663#endif 1664 return (m); 1665} 1666 1667/* 1668 * Strip out IP options, at higher 1669 * level protocol in the kernel. 1670 * Second argument is buffer to which options 1671 * will be moved, and return value is their length. 1672 * XXX should be deleted; last arg currently ignored. 1673 */ 1674void 1675ip_stripoptions(m, mopt) 1676 register struct mbuf *m; 1677 struct mbuf *mopt; 1678{ 1679 register int i; 1680 struct ip *ip = mtod(m, struct ip *); 1681 register caddr_t opts; 1682 int olen; 1683 1684 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1685 opts = (caddr_t)(ip + 1); 1686 i = m->m_len - (sizeof (struct ip) + olen); 1687 bcopy(opts + olen, opts, (unsigned)i); 1688 m->m_len -= olen; 1689 if (m->m_flags & M_PKTHDR) 1690 m->m_pkthdr.len -= olen; 1691 ip->ip_v = IPVERSION; 1692 ip->ip_hl = sizeof(struct ip) >> 2; 1693} 1694 1695u_char inetctlerrmap[PRC_NCMDS] = { 1696 0, 0, 0, 0, 1697 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1698 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1699 EMSGSIZE, EHOSTUNREACH, 0, 0, 1700 0, 0, 0, 0, 1701 ENOPROTOOPT, ECONNREFUSED 1702}; 1703 1704/* 1705 * Forward a packet. If some error occurs return the sender 1706 * an icmp packet. Note we can't always generate a meaningful 1707 * icmp message because icmp doesn't have a large enough repertoire 1708 * of codes and types. 1709 * 1710 * If not forwarding, just drop the packet. This could be confusing 1711 * if ipforwarding was zero but some routing protocol was advancing 1712 * us as a gateway to somewhere. However, we must let the routing 1713 * protocol deal with that. 1714 * 1715 * The srcrt parameter indicates whether the packet is being forwarded 1716 * via a source route. 1717 */ 1718static void 1719ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop) 1720{ 1721 struct ip *ip = mtod(m, struct ip *); 1722 struct rtentry *rt; 1723 int error, type = 0, code = 0; 1724 struct mbuf *mcopy; 1725 n_long dest; 1726 struct in_addr pkt_dst; 1727 struct ifnet *destifp; 1728#if defined(IPSEC) || defined(FAST_IPSEC) 1729 struct ifnet dummyifp; 1730#endif 1731 1732 dest = 0; 1733 /* 1734 * Cache the destination address of the packet; this may be 1735 * changed by use of 'ipfw fwd'. 1736 */ 1737 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 1738 1739#ifdef DIAGNOSTIC 1740 if (ipprintfs) 1741 printf("forward: src %lx dst %lx ttl %x\n", 1742 (u_long)ip->ip_src.s_addr, (u_long)pkt_dst.s_addr, 1743 ip->ip_ttl); 1744#endif 1745 1746 1747 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(pkt_dst) == 0) { 1748 ipstat.ips_cantforward++; 1749 m_freem(m); 1750 return; 1751 } 1752#ifdef IPSTEALTH 1753 if (!ipstealth) { 1754#endif 1755 if (ip->ip_ttl <= IPTTLDEC) { 1756 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1757 dest, 0); 1758 return; 1759 } 1760#ifdef IPSTEALTH 1761 } 1762#endif 1763 1764 if (ip_rtaddr(pkt_dst, &ipforward_rt) == 0) { 1765 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1766 return; 1767 } else 1768 rt = ipforward_rt.ro_rt; 1769 1770 /* 1771 * Save the IP header and at most 8 bytes of the payload, 1772 * in case we need to generate an ICMP message to the src. 1773 * 1774 * XXX this can be optimized a lot by saving the data in a local 1775 * buffer on the stack (72 bytes at most), and only allocating the 1776 * mbuf if really necessary. The vast majority of the packets 1777 * are forwarded without having to send an ICMP back (either 1778 * because unnecessary, or because rate limited), so we are 1779 * really we are wasting a lot of work here. 1780 * 1781 * We don't use m_copy() because it might return a reference 1782 * to a shared cluster. Both this function and ip_output() 1783 * assume exclusive access to the IP header in `m', so any 1784 * data in a cluster may change before we reach icmp_error(). 1785 */ 1786 MGET(mcopy, M_DONTWAIT, m->m_type); 1787 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1788 /* 1789 * It's probably ok if the pkthdr dup fails (because 1790 * the deep copy of the tag chain failed), but for now 1791 * be conservative and just discard the copy since 1792 * code below may some day want the tags. 1793 */ 1794 m_free(mcopy); 1795 mcopy = NULL; 1796 } 1797 if (mcopy != NULL) { 1798 mcopy->m_len = imin((ip->ip_hl << 2) + 8, 1799 (int)ip->ip_len); 1800 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1801#ifdef MAC 1802 /* 1803 * XXXMAC: This will eventually become an explicit 1804 * labeling point. 1805 */ 1806 mac_create_mbuf_from_mbuf(m, mcopy); 1807#endif 1808 } 1809 1810#ifdef IPSTEALTH 1811 if (!ipstealth) { 1812#endif 1813 ip->ip_ttl -= IPTTLDEC; 1814#ifdef IPSTEALTH 1815 } 1816#endif 1817 1818 /* 1819 * If forwarding packet using same interface that it came in on, 1820 * perhaps should send a redirect to sender to shortcut a hop. 1821 * Only send redirect if source is sending directly to us, 1822 * and if packet was not source routed (or has any options). 1823 * Also, don't send redirect if forwarding using a default route 1824 * or a route modified by a redirect. 1825 */ 1826 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1827 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1828 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1829 ipsendredirects && !srcrt && !next_hop) { 1830#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1831 u_long src = ntohl(ip->ip_src.s_addr); 1832 1833 if (RTA(rt) && 1834 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1835 if (rt->rt_flags & RTF_GATEWAY) 1836 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1837 else 1838 dest = pkt_dst.s_addr; 1839 /* Router requirements says to only send host redirects */ 1840 type = ICMP_REDIRECT; 1841 code = ICMP_REDIRECT_HOST; 1842#ifdef DIAGNOSTIC 1843 if (ipprintfs) 1844 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1845#endif 1846 } 1847 } 1848 1849 { 1850 struct m_hdr tag; 1851 1852 if (next_hop) { 1853 /* Pass IPFORWARD info if available */ 1854 1855 tag.mh_type = MT_TAG; 1856 tag.mh_flags = PACKET_TAG_IPFORWARD; 1857 tag.mh_data = (caddr_t)next_hop; 1858 tag.mh_next = m; 1859 m = (struct mbuf *)&tag; 1860 } 1861 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1862 IP_FORWARDING, 0, NULL); 1863 } 1864 if (error) 1865 ipstat.ips_cantforward++; 1866 else { 1867 ipstat.ips_forward++; 1868 if (type) 1869 ipstat.ips_redirectsent++; 1870 else { 1871 if (mcopy) { 1872 ipflow_create(&ipforward_rt, mcopy); 1873 m_freem(mcopy); 1874 } 1875 return; 1876 } 1877 } 1878 if (mcopy == NULL) 1879 return; 1880 destifp = NULL; 1881 1882 switch (error) { 1883 1884 case 0: /* forwarded, but need redirect */ 1885 /* type, code set above */ 1886 break; 1887 1888 case ENETUNREACH: /* shouldn't happen, checked above */ 1889 case EHOSTUNREACH: 1890 case ENETDOWN: 1891 case EHOSTDOWN: 1892 default: 1893 type = ICMP_UNREACH; 1894 code = ICMP_UNREACH_HOST; 1895 break; 1896 1897 case EMSGSIZE: 1898 type = ICMP_UNREACH; 1899 code = ICMP_UNREACH_NEEDFRAG; 1900#ifdef IPSEC 1901 /* 1902 * If the packet is routed over IPsec tunnel, tell the 1903 * originator the tunnel MTU. 1904 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1905 * XXX quickhack!!! 1906 */ 1907 if (ipforward_rt.ro_rt) { 1908 struct secpolicy *sp = NULL; 1909 int ipsecerror; 1910 int ipsechdr; 1911 struct route *ro; 1912 1913 sp = ipsec4_getpolicybyaddr(mcopy, 1914 IPSEC_DIR_OUTBOUND, 1915 IP_FORWARDING, 1916 &ipsecerror); 1917 1918 if (sp == NULL) 1919 destifp = ipforward_rt.ro_rt->rt_ifp; 1920 else { 1921 /* count IPsec header size */ 1922 ipsechdr = ipsec4_hdrsiz(mcopy, 1923 IPSEC_DIR_OUTBOUND, 1924 NULL); 1925 1926 /* 1927 * find the correct route for outer IPv4 1928 * header, compute tunnel MTU. 1929 * 1930 * XXX BUG ALERT 1931 * The "dummyifp" code relies upon the fact 1932 * that icmp_error() touches only ifp->if_mtu. 1933 */ 1934 /*XXX*/ 1935 destifp = NULL; 1936 if (sp->req != NULL 1937 && sp->req->sav != NULL 1938 && sp->req->sav->sah != NULL) { 1939 ro = &sp->req->sav->sah->sa_route; 1940 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1941 dummyifp.if_mtu = 1942 ro->ro_rt->rt_ifp->if_mtu; 1943 dummyifp.if_mtu -= ipsechdr; 1944 destifp = &dummyifp; 1945 } 1946 } 1947 1948 key_freesp(sp); 1949 } 1950 } 1951#elif FAST_IPSEC 1952 /* 1953 * If the packet is routed over IPsec tunnel, tell the 1954 * originator the tunnel MTU. 1955 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1956 * XXX quickhack!!! 1957 */ 1958 if (ipforward_rt.ro_rt) { 1959 struct secpolicy *sp = NULL; 1960 int ipsecerror; 1961 int ipsechdr; 1962 struct route *ro; 1963 1964 sp = ipsec_getpolicybyaddr(mcopy, 1965 IPSEC_DIR_OUTBOUND, 1966 IP_FORWARDING, 1967 &ipsecerror); 1968 1969 if (sp == NULL) 1970 destifp = ipforward_rt.ro_rt->rt_ifp; 1971 else { 1972 /* count IPsec header size */ 1973 ipsechdr = ipsec4_hdrsiz(mcopy, 1974 IPSEC_DIR_OUTBOUND, 1975 NULL); 1976 1977 /* 1978 * find the correct route for outer IPv4 1979 * header, compute tunnel MTU. 1980 * 1981 * XXX BUG ALERT 1982 * The "dummyifp" code relies upon the fact 1983 * that icmp_error() touches only ifp->if_mtu. 1984 */ 1985 /*XXX*/ 1986 destifp = NULL; 1987 if (sp->req != NULL 1988 && sp->req->sav != NULL 1989 && sp->req->sav->sah != NULL) { 1990 ro = &sp->req->sav->sah->sa_route; 1991 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1992 dummyifp.if_mtu = 1993 ro->ro_rt->rt_ifp->if_mtu; 1994 dummyifp.if_mtu -= ipsechdr; 1995 destifp = &dummyifp; 1996 } 1997 } 1998 1999 KEY_FREESP(&sp); 2000 } 2001 } 2002#else /* !IPSEC && !FAST_IPSEC */ 2003 if (ipforward_rt.ro_rt) 2004 destifp = ipforward_rt.ro_rt->rt_ifp; 2005#endif /*IPSEC*/ 2006 ipstat.ips_cantfrag++; 2007 break; 2008 2009 case ENOBUFS: 2010 /* 2011 * A router should not generate ICMP_SOURCEQUENCH as 2012 * required in RFC1812 Requirements for IP Version 4 Routers. 2013 * Source quench could be a big problem under DoS attacks, 2014 * or if the underlying interface is rate-limited. 2015 * Those who need source quench packets may re-enable them 2016 * via the net.inet.ip.sendsourcequench sysctl. 2017 */ 2018 if (ip_sendsourcequench == 0) { 2019 m_freem(mcopy); 2020 return; 2021 } else { 2022 type = ICMP_SOURCEQUENCH; 2023 code = 0; 2024 } 2025 break; 2026 2027 case EACCES: /* ipfw denied packet */ 2028 m_freem(mcopy); 2029 return; 2030 } 2031 icmp_error(mcopy, type, code, dest, destifp); 2032} 2033 2034void 2035ip_savecontrol(inp, mp, ip, m) 2036 register struct inpcb *inp; 2037 register struct mbuf **mp; 2038 register struct ip *ip; 2039 register struct mbuf *m; 2040{ 2041 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2042 struct timeval tv; 2043 2044 microtime(&tv); 2045 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2046 SCM_TIMESTAMP, SOL_SOCKET); 2047 if (*mp) 2048 mp = &(*mp)->m_next; 2049 } 2050 if (inp->inp_flags & INP_RECVDSTADDR) { 2051 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2052 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2053 if (*mp) 2054 mp = &(*mp)->m_next; 2055 } 2056#ifdef notyet 2057 /* XXX 2058 * Moving these out of udp_input() made them even more broken 2059 * than they already were. 2060 */ 2061 /* options were tossed already */ 2062 if (inp->inp_flags & INP_RECVOPTS) { 2063 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2064 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2065 if (*mp) 2066 mp = &(*mp)->m_next; 2067 } 2068 /* ip_srcroute doesn't do what we want here, need to fix */ 2069 if (inp->inp_flags & INP_RECVRETOPTS) { 2070 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2071 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2072 if (*mp) 2073 mp = &(*mp)->m_next; 2074 } 2075#endif 2076 if (inp->inp_flags & INP_RECVIF) { 2077 struct ifnet *ifp; 2078 struct sdlbuf { 2079 struct sockaddr_dl sdl; 2080 u_char pad[32]; 2081 } sdlbuf; 2082 struct sockaddr_dl *sdp; 2083 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2084 2085 if (((ifp = m->m_pkthdr.rcvif)) 2086 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2087 sdp = (struct sockaddr_dl *) 2088 (ifaddr_byindex(ifp->if_index)->ifa_addr); 2089 /* 2090 * Change our mind and don't try copy. 2091 */ 2092 if ((sdp->sdl_family != AF_LINK) 2093 || (sdp->sdl_len > sizeof(sdlbuf))) { 2094 goto makedummy; 2095 } 2096 bcopy(sdp, sdl2, sdp->sdl_len); 2097 } else { 2098makedummy: 2099 sdl2->sdl_len 2100 = offsetof(struct sockaddr_dl, sdl_data[0]); 2101 sdl2->sdl_family = AF_LINK; 2102 sdl2->sdl_index = 0; 2103 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2104 } 2105 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2106 IP_RECVIF, IPPROTO_IP); 2107 if (*mp) 2108 mp = &(*mp)->m_next; 2109 } 2110} 2111 2112/* 2113 * XXX these routines are called from the upper part of the kernel. 2114 * They need to be locked when we remove Giant. 2115 * 2116 * They could also be moved to ip_mroute.c, since all the RSVP 2117 * handling is done there already. 2118 */ 2119static int ip_rsvp_on; 2120struct socket *ip_rsvpd; 2121int 2122ip_rsvp_init(struct socket *so) 2123{ 2124 if (so->so_type != SOCK_RAW || 2125 so->so_proto->pr_protocol != IPPROTO_RSVP) 2126 return EOPNOTSUPP; 2127 2128 if (ip_rsvpd != NULL) 2129 return EADDRINUSE; 2130 2131 ip_rsvpd = so; 2132 /* 2133 * This may seem silly, but we need to be sure we don't over-increment 2134 * the RSVP counter, in case something slips up. 2135 */ 2136 if (!ip_rsvp_on) { 2137 ip_rsvp_on = 1; 2138 rsvp_on++; 2139 } 2140 2141 return 0; 2142} 2143 2144int 2145ip_rsvp_done(void) 2146{ 2147 ip_rsvpd = NULL; 2148 /* 2149 * This may seem silly, but we need to be sure we don't over-decrement 2150 * the RSVP counter, in case something slips up. 2151 */ 2152 if (ip_rsvp_on) { 2153 ip_rsvp_on = 0; 2154 rsvp_on--; 2155 } 2156 return 0; 2157} 2158 2159void 2160rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 2161{ 2162 if (rsvp_input_p) { /* call the real one if loaded */ 2163 rsvp_input_p(m, off); 2164 return; 2165 } 2166 2167 /* Can still get packets with rsvp_on = 0 if there is a local member 2168 * of the group to which the RSVP packet is addressed. But in this 2169 * case we want to throw the packet away. 2170 */ 2171 2172 if (!rsvp_on) { 2173 m_freem(m); 2174 return; 2175 } 2176 2177 if (ip_rsvpd != NULL) { 2178 rip_input(m, off); 2179 return; 2180 } 2181 /* Drop the packet */ 2182 m_freem(m); 2183} 2184