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_ipdn.h" 36 #include "opt_ipdivert.h" 37 #include "opt_ipfilter.h" 38 #include "opt_ipstealth.h" 39 #include "opt_ipsec.h" 40 #include "opt_mac.h" 41 #include "opt_pfil_hooks.h" 42 #include "opt_random_ip_id.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/mac.h> 47 #include <sys/mbuf.h> 48 #include <sys/malloc.h> 49 #include <sys/domain.h> 50 #include <sys/protosw.h> 51 #include <sys/socket.h> 52 #include <sys/time.h> 53 #include <sys/kernel.h> 54 #include <sys/syslog.h> 55 #include <sys/sysctl.h> 56 57 #include <net/pfil.h> 58 #include <net/if.h> 59 #include <net/if_types.h> 60 #include <net/if_var.h> 61 #include <net/if_dl.h> 62 #include <net/route.h> 63 #include <net/netisr.h> 64 65 #include <netinet/in.h> 66 #include <netinet/in_systm.h> 67 #include <netinet/in_var.h> 68 #include <netinet/ip.h> 69 #include <netinet/in_pcb.h> 70 #include <netinet/ip_var.h> 71 #include <netinet/ip_icmp.h> 72 #include <machine/in_cksum.h> 73 74 #include <sys/socketvar.h> 75 76 #include <netinet/ip_fw.h> 77 #include <netinet/ip_divert.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 static int ip_keepfaith = 0; 114 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 115 &ip_keepfaith, 0, 116 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 117 118 static int nipq = 0; /* total # of reass queues */ 119 static int maxnipq; 120 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 121 &maxnipq, 0, 122 "Maximum number of IPv4 fragment reassembly queue entries"); 123 124 static int maxfragsperpacket; 125 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 126 &maxfragsperpacket, 0, 127 "Maximum number of IPv4 fragments allowed per packet"); 128 129 static int ip_sendsourcequench = 0; 130 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 131 &ip_sendsourcequench, 0, 132 "Enable the transmission of source quench packets"); 133 134 /* 135 * XXX - Setting ip_checkinterface mostly implements the receive side of 136 * the Strong ES model described in RFC 1122, but since the routing table 137 * and transmit implementation do not implement the Strong ES model, 138 * setting this to 1 results in an odd hybrid. 139 * 140 * XXX - ip_checkinterface currently must be disabled if you use ipnat 141 * to translate the destination address to another local interface. 142 * 143 * XXX - ip_checkinterface must be disabled if you add IP aliases 144 * to the loopback interface instead of the interface where the 145 * packets for those addresses are received. 146 */ 147 static int ip_checkinterface = 1; 148 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 149 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 150 151 #ifdef DIAGNOSTIC 152 static int ipprintfs = 0; 153 #endif 154 #ifdef PFIL_HOOKS 155 struct pfil_head inet_pfil_hook; 156 #endif 157 158 static struct ifqueue ipintrq; 159 static int ipqmaxlen = IFQ_MAXLEN; 160 161 extern struct domain inetdomain; 162 extern struct protosw inetsw[]; 163 u_char ip_protox[IPPROTO_MAX]; 164 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 165 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 166 u_long in_ifaddrhmask; /* mask for hash table */ 167 168 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 169 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 170 SYSCTL_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"); 172 173 struct ipstat ipstat; 174 SYSCTL_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) 183 184 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 185 struct mtx ipqlock; 186 187 #define IPQ_LOCK() mtx_lock(&ipqlock) 188 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 189 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 190 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 191 192 #ifdef IPCTL_DEFMTU 193 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 194 &ip_mtu, 0, "Default MTU"); 195 #endif 196 197 #ifdef IPSTEALTH 198 int ipstealth = 0; 199 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 200 &ipstealth, 0, ""); 201 #endif 202 203 204 /* Firewall hooks */ 205 ip_fw_chk_t *ip_fw_chk_ptr; 206 int fw_enable = 1 ; 207 int fw_one_pass = 1; 208 209 /* Dummynet hooks */ 210 ip_dn_io_t *ip_dn_io_ptr; 211 212 /* 213 * XXX this is ugly -- the following two global variables are 214 * used to store packet state while it travels through the stack. 215 * Note that the code even makes assumptions on the size and 216 * alignment of fields inside struct ip_srcrt so e.g. adding some 217 * fields will break the code. This needs to be fixed. 218 * 219 * We need to save the IP options in case a protocol wants to respond 220 * to an incoming packet over the same route if the packet got here 221 * using IP source routing. This allows connection establishment and 222 * maintenance when the remote end is on a network that is not known 223 * to us. 224 */ 225 static int ip_nhops = 0; 226 static struct ip_srcrt { 227 struct in_addr dst; /* final destination */ 228 char nop; /* one NOP to align */ 229 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 230 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 231 } ip_srcrt; 232 233 static void save_rte(u_char *, struct in_addr); 234 static int ip_dooptions(struct mbuf *m, int, 235 struct sockaddr_in *next_hop); 236 static void ip_forward(struct mbuf *m, int srcrt, 237 struct sockaddr_in *next_hop); 238 static void ip_freef(struct ipqhead *, struct ipq *); 239 static struct mbuf *ip_reass(struct mbuf *, struct ipqhead *, struct ipq *); 240 241 /* 242 * IP initialization: fill in IP protocol switch table. 243 * All protocols not implemented in kernel go to raw IP protocol handler. 244 */ 245 void 246 ip_init() 247 { 248 register struct protosw *pr; 249 register int i; 250 251 TAILQ_INIT(&in_ifaddrhead); 252 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 253 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 254 if (pr == 0) 255 panic("ip_init"); 256 for (i = 0; i < IPPROTO_MAX; i++) 257 ip_protox[i] = pr - inetsw; 258 for (pr = inetdomain.dom_protosw; 259 pr < inetdomain.dom_protoswNPROTOSW; pr++) 260 if (pr->pr_domain->dom_family == PF_INET && 261 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 262 ip_protox[pr->pr_protocol] = pr - inetsw; 263 264 #ifdef PFIL_HOOKS 265 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 266 inet_pfil_hook.ph_af = AF_INET; 267 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 268 printf("%s: WARNING: unable to register pfil hook, " 269 "error %d\n", __func__, i); 270 #endif /* PFIL_HOOKS */ 271 272 IPQ_LOCK_INIT(); 273 for (i = 0; i < IPREASS_NHASH; i++) 274 TAILQ_INIT(&ipq[i]); 275 276 maxnipq = nmbclusters / 32; 277 maxfragsperpacket = 16; 278 279 #ifndef RANDOM_IP_ID 280 ip_id = time_second & 0xffff; 281 #endif 282 ipintrq.ifq_maxlen = ipqmaxlen; 283 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 284 netisr_register(NETISR_IP, ip_input, &ipintrq, NETISR_MPSAFE); 285 } 286 287 /* 288 * Ip input routine. Checksum and byte swap header. If fragmented 289 * try to reassemble. Process options. Pass to next level. 290 */ 291 void 292 ip_input(struct mbuf *m) 293 { 294 struct ip *ip = NULL; 295 struct ipq *fp; 296 struct in_ifaddr *ia = NULL; 297 struct ifaddr *ifa; 298 int i, checkif, hlen = 0; 299 u_short sum; 300 struct in_addr pkt_dst; 301 #ifdef IPDIVERT 302 u_int32_t divert_info; /* packet divert/tee info */ 303 #endif 304 struct ip_fw_args args; 305 int dchg = 0; /* dest changed after fw */ 306 #ifdef PFIL_HOOKS 307 struct in_addr odst; /* original dst address */ 308 #endif 309 #ifdef FAST_IPSEC 310 struct m_tag *mtag; 311 struct tdb_ident *tdbi; 312 struct secpolicy *sp; 313 int s, error; 314 #endif /* FAST_IPSEC */ 315 316 args.eh = NULL; 317 args.oif = NULL; 318 319 M_ASSERTPKTHDR(m); 320 321 args.next_hop = ip_claim_next_hop(m); 322 args.rule = ip_dn_claim_rule(m); 323 324 if (m->m_flags & M_FASTFWD_OURS) { 325 /* ip_fastforward firewall changed dest to local */ 326 m->m_flags &= ~M_FASTFWD_OURS; /* for reflected mbufs */ 327 goto ours; 328 } 329 330 if (args.rule) { /* dummynet already filtered us */ 331 ip = mtod(m, struct ip *); 332 hlen = ip->ip_hl << 2; 333 goto iphack ; 334 } 335 336 ipstat.ips_total++; 337 338 if (m->m_pkthdr.len < sizeof(struct ip)) 339 goto tooshort; 340 341 if (m->m_len < sizeof (struct ip) && 342 (m = m_pullup(m, sizeof (struct ip))) == 0) { 343 ipstat.ips_toosmall++; 344 return; 345 } 346 ip = mtod(m, struct ip *); 347 348 if (ip->ip_v != IPVERSION) { 349 ipstat.ips_badvers++; 350 goto bad; 351 } 352 353 hlen = ip->ip_hl << 2; 354 if (hlen < sizeof(struct ip)) { /* minimum header length */ 355 ipstat.ips_badhlen++; 356 goto bad; 357 } 358 if (hlen > m->m_len) { 359 if ((m = m_pullup(m, hlen)) == 0) { 360 ipstat.ips_badhlen++; 361 return; 362 } 363 ip = mtod(m, struct ip *); 364 } 365 366 /* 127/8 must not appear on wire - RFC1122 */ 367 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 368 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 369 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 370 ipstat.ips_badaddr++; 371 goto bad; 372 } 373 } 374 375 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 376 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 377 } else { 378 if (hlen == sizeof(struct ip)) { 379 sum = in_cksum_hdr(ip); 380 } else { 381 sum = in_cksum(m, hlen); 382 } 383 } 384 if (sum) { 385 ipstat.ips_badsum++; 386 goto bad; 387 } 388 389 /* 390 * Convert fields to host representation. 391 */ 392 ip->ip_len = ntohs(ip->ip_len); 393 if (ip->ip_len < hlen) { 394 ipstat.ips_badlen++; 395 goto bad; 396 } 397 ip->ip_off = ntohs(ip->ip_off); 398 399 /* 400 * Check that the amount of data in the buffers 401 * is as at least much as the IP header would have us expect. 402 * Trim mbufs if longer than we expect. 403 * Drop packet if shorter than we expect. 404 */ 405 if (m->m_pkthdr.len < ip->ip_len) { 406 tooshort: 407 ipstat.ips_tooshort++; 408 goto bad; 409 } 410 if (m->m_pkthdr.len > ip->ip_len) { 411 if (m->m_len == m->m_pkthdr.len) { 412 m->m_len = ip->ip_len; 413 m->m_pkthdr.len = ip->ip_len; 414 } else 415 m_adj(m, ip->ip_len - m->m_pkthdr.len); 416 } 417 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 418 /* 419 * Bypass packet filtering for packets from a tunnel (gif). 420 */ 421 if (ipsec_getnhist(m)) 422 goto pass; 423 #endif 424 #if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF) 425 /* 426 * Bypass packet filtering for packets from a tunnel (gif). 427 */ 428 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 429 goto pass; 430 #endif 431 432 /* 433 * IpHack's section. 434 * Right now when no processing on packet has done 435 * and it is still fresh out of network we do our black 436 * deals with it. 437 * - Firewall: deny/allow/divert 438 * - Xlate: translate packet's addr/port (NAT). 439 * - Pipe: pass pkt through dummynet. 440 * - Wrap: fake packet's addr/port <unimpl.> 441 * - Encapsulate: put it in another IP and send out. <unimp.> 442 */ 443 444 iphack: 445 446 #ifdef PFIL_HOOKS 447 /* 448 * Run through list of hooks for input packets. 449 * 450 * NB: Beware of the destination address changing (e.g. 451 * by NAT rewriting). When this happens, tell 452 * ip_forward to do the right thing. 453 */ 454 odst = ip->ip_dst; 455 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 456 PFIL_IN) != 0) 457 return; 458 if (m == NULL) /* consumed by filter */ 459 return; 460 ip = mtod(m, struct ip *); 461 dchg = (odst.s_addr != ip->ip_dst.s_addr); 462 #endif /* PFIL_HOOKS */ 463 464 if (fw_enable && IPFW_LOADED) { 465 /* 466 * If we've been forwarded from the output side, then 467 * skip the firewall a second time 468 */ 469 if (args.next_hop) 470 goto ours; 471 472 args.m = m; 473 i = ip_fw_chk_ptr(&args); 474 m = args.m; 475 476 if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 477 if (m) 478 m_freem(m); 479 return; 480 } 481 ip = mtod(m, struct ip *); /* just in case m changed */ 482 if (i == 0 && args.next_hop == NULL) /* common case */ 483 goto pass; 484 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) { 485 /* Send packet to the appropriate pipe */ 486 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 487 return; 488 } 489 #ifdef IPDIVERT 490 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 491 /* Divert or tee packet */ 492 goto ours; 493 } 494 #endif 495 if (i == 0 && args.next_hop != NULL) 496 goto pass; 497 /* 498 * if we get here, the packet must be dropped 499 */ 500 m_freem(m); 501 return; 502 } 503 pass: 504 505 /* 506 * Process options and, if not destined for us, 507 * ship it on. ip_dooptions returns 1 when an 508 * error was detected (causing an icmp message 509 * to be sent and the original packet to be freed). 510 */ 511 ip_nhops = 0; /* for source routed packets */ 512 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, args.next_hop)) 513 return; 514 515 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 516 * matter if it is destined to another node, or whether it is 517 * a multicast one, RSVP wants it! and prevents it from being forwarded 518 * anywhere else. Also checks if the rsvp daemon is running before 519 * grabbing the packet. 520 */ 521 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 522 goto ours; 523 524 /* 525 * Check our list of addresses, to see if the packet is for us. 526 * If we don't have any addresses, assume any unicast packet 527 * we receive might be for us (and let the upper layers deal 528 * with it). 529 */ 530 if (TAILQ_EMPTY(&in_ifaddrhead) && 531 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 532 goto ours; 533 534 /* 535 * Cache the destination address of the packet; this may be 536 * changed by use of 'ipfw fwd'. 537 */ 538 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 539 540 /* 541 * Enable a consistency check between the destination address 542 * and the arrival interface for a unicast packet (the RFC 1122 543 * strong ES model) if IP forwarding is disabled and the packet 544 * is not locally generated and the packet is not subject to 545 * 'ipfw fwd'. 546 * 547 * XXX - Checking also should be disabled if the destination 548 * address is ipnat'ed to a different interface. 549 * 550 * XXX - Checking is incompatible with IP aliases added 551 * to the loopback interface instead of the interface where 552 * the packets are received. 553 */ 554 checkif = ip_checkinterface && (ipforwarding == 0) && 555 m->m_pkthdr.rcvif != NULL && 556 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 557 (args.next_hop == NULL) && (dchg == 0); 558 559 /* 560 * Check for exact addresses in the hash bucket. 561 */ 562 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 563 /* 564 * If the address matches, verify that the packet 565 * arrived via the correct interface if checking is 566 * enabled. 567 */ 568 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 569 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 570 goto ours; 571 } 572 /* 573 * Check for broadcast addresses. 574 * 575 * Only accept broadcast packets that arrive via the matching 576 * interface. Reception of forwarded directed broadcasts would 577 * be handled via ip_forward() and ether_output() with the loopback 578 * into the stack for SIMPLEX interfaces handled by ether_output(). 579 */ 580 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 581 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 582 if (ifa->ifa_addr->sa_family != AF_INET) 583 continue; 584 ia = ifatoia(ifa); 585 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 586 pkt_dst.s_addr) 587 goto ours; 588 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 589 goto ours; 590 #ifdef BOOTP_COMPAT 591 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 592 goto ours; 593 #endif 594 } 595 } 596 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 597 struct in_multi *inm; 598 if (ip_mrouter) { 599 /* 600 * If we are acting as a multicast router, all 601 * incoming multicast packets are passed to the 602 * kernel-level multicast forwarding function. 603 * The packet is returned (relatively) intact; if 604 * ip_mforward() returns a non-zero value, the packet 605 * must be discarded, else it may be accepted below. 606 */ 607 if (ip_mforward && 608 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 609 ipstat.ips_cantforward++; 610 m_freem(m); 611 return; 612 } 613 614 /* 615 * The process-level routing daemon needs to receive 616 * all multicast IGMP packets, whether or not this 617 * host belongs to their destination groups. 618 */ 619 if (ip->ip_p == IPPROTO_IGMP) 620 goto ours; 621 ipstat.ips_forward++; 622 } 623 /* 624 * See if we belong to the destination multicast group on the 625 * arrival interface. 626 */ 627 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 628 if (inm == NULL) { 629 ipstat.ips_notmember++; 630 m_freem(m); 631 return; 632 } 633 goto ours; 634 } 635 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 636 goto ours; 637 if (ip->ip_dst.s_addr == INADDR_ANY) 638 goto ours; 639 640 /* 641 * FAITH(Firewall Aided Internet Translator) 642 */ 643 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 644 if (ip_keepfaith) { 645 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 646 goto ours; 647 } 648 m_freem(m); 649 return; 650 } 651 652 /* 653 * Not for us; forward if possible and desirable. 654 */ 655 if (ipforwarding == 0) { 656 ipstat.ips_cantforward++; 657 m_freem(m); 658 } else { 659 #ifdef IPSEC 660 /* 661 * Enforce inbound IPsec SPD. 662 */ 663 if (ipsec4_in_reject(m, NULL)) { 664 ipsecstat.in_polvio++; 665 goto bad; 666 } 667 #endif /* IPSEC */ 668 #ifdef FAST_IPSEC 669 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 670 s = splnet(); 671 if (mtag != NULL) { 672 tdbi = (struct tdb_ident *)(mtag + 1); 673 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 674 } else { 675 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 676 IP_FORWARDING, &error); 677 } 678 if (sp == NULL) { /* NB: can happen if error */ 679 splx(s); 680 /*XXX error stat???*/ 681 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 682 goto bad; 683 } 684 685 /* 686 * Check security policy against packet attributes. 687 */ 688 error = ipsec_in_reject(sp, m); 689 KEY_FREESP(&sp); 690 splx(s); 691 if (error) { 692 ipstat.ips_cantforward++; 693 goto bad; 694 } 695 #endif /* FAST_IPSEC */ 696 ip_forward(m, dchg, args.next_hop); 697 } 698 return; 699 700 ours: 701 #ifdef IPSTEALTH 702 /* 703 * IPSTEALTH: Process non-routing options only 704 * if the packet is destined for us. 705 */ 706 if (ipstealth && hlen > sizeof (struct ip) && 707 ip_dooptions(m, 1, args.next_hop)) 708 return; 709 #endif /* IPSTEALTH */ 710 711 /* Count the packet in the ip address stats */ 712 if (ia != NULL) { 713 ia->ia_ifa.if_ipackets++; 714 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 715 } 716 717 /* 718 * If offset or IP_MF are set, must reassemble. 719 * Otherwise, nothing need be done. 720 * (We could look in the reassembly queue to see 721 * if the packet was previously fragmented, 722 * but it's not worth the time; just let them time out.) 723 */ 724 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 725 726 /* If maxnipq is 0, never accept fragments. */ 727 if (maxnipq == 0) { 728 ipstat.ips_fragments++; 729 ipstat.ips_fragdropped++; 730 goto bad; 731 } 732 733 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 734 IPQ_LOCK(); 735 /* 736 * Look for queue of fragments 737 * of this datagram. 738 */ 739 TAILQ_FOREACH(fp, &ipq[sum], ipq_list) 740 if (ip->ip_id == fp->ipq_id && 741 ip->ip_src.s_addr == fp->ipq_src.s_addr && 742 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 743 #ifdef MAC 744 mac_fragment_match(m, fp) && 745 #endif 746 ip->ip_p == fp->ipq_p) 747 goto found; 748 749 fp = NULL; 750 751 /* 752 * Enforce upper bound on number of fragmented packets 753 * for which we attempt reassembly; 754 * If maxnipq is -1, accept all fragments without limitation. 755 */ 756 if ((nipq > maxnipq) && (maxnipq > 0)) { 757 /* 758 * drop something from the tail of the current queue 759 * before proceeding further 760 */ 761 struct ipq *q = TAILQ_LAST(&ipq[sum], ipqhead); 762 if (q == NULL) { /* gak */ 763 for (i = 0; i < IPREASS_NHASH; i++) { 764 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 765 if (r) { 766 ipstat.ips_fragtimeout += r->ipq_nfrags; 767 ip_freef(&ipq[i], r); 768 break; 769 } 770 } 771 } else { 772 ipstat.ips_fragtimeout += q->ipq_nfrags; 773 ip_freef(&ipq[sum], q); 774 } 775 } 776 found: 777 /* 778 * Adjust ip_len to not reflect header, 779 * convert offset of this to bytes. 780 */ 781 ip->ip_len -= hlen; 782 if (ip->ip_off & IP_MF) { 783 /* 784 * Make sure that fragments have a data length 785 * that's a non-zero multiple of 8 bytes. 786 */ 787 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 788 IPQ_UNLOCK(); 789 ipstat.ips_toosmall++; /* XXX */ 790 goto bad; 791 } 792 m->m_flags |= M_FRAG; 793 } else 794 m->m_flags &= ~M_FRAG; 795 ip->ip_off <<= 3; 796 797 /* 798 * Attempt reassembly; if it succeeds, proceed. 799 * ip_reass() will return a different mbuf. 800 */ 801 ipstat.ips_fragments++; 802 m->m_pkthdr.header = ip; 803 m = ip_reass(m, &ipq[sum], fp); 804 IPQ_UNLOCK(); 805 if (m == 0) 806 return; 807 ipstat.ips_reassembled++; 808 ip = mtod(m, struct ip *); 809 /* Get the header length of the reassembled packet */ 810 hlen = ip->ip_hl << 2; 811 #ifdef IPDIVERT 812 /* Restore original checksum before diverting packet */ 813 if (divert_find_info(m) != 0) { 814 ip->ip_len += hlen; 815 ip->ip_len = htons(ip->ip_len); 816 ip->ip_off = htons(ip->ip_off); 817 ip->ip_sum = 0; 818 if (hlen == sizeof(struct ip)) 819 ip->ip_sum = in_cksum_hdr(ip); 820 else 821 ip->ip_sum = in_cksum(m, hlen); 822 ip->ip_off = ntohs(ip->ip_off); 823 ip->ip_len = ntohs(ip->ip_len); 824 ip->ip_len -= hlen; 825 } 826 #endif 827 } else 828 ip->ip_len -= hlen; 829 830 #ifdef IPDIVERT 831 /* 832 * Divert or tee packet to the divert protocol if required. 833 */ 834 divert_info = divert_find_info(m); 835 if (divert_info != 0) { 836 struct mbuf *clone; 837 838 /* Clone packet if we're doing a 'tee' */ 839 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 840 clone = divert_clone(m); 841 else 842 clone = NULL; 843 844 /* Restore packet header fields to original values */ 845 ip->ip_len += hlen; 846 ip->ip_len = htons(ip->ip_len); 847 ip->ip_off = htons(ip->ip_off); 848 849 /* Deliver packet to divert input routine */ 850 divert_packet(m, 1); 851 ipstat.ips_delivered++; 852 853 /* If 'tee', continue with original packet */ 854 if (clone == NULL) 855 return; 856 m = clone; 857 ip = mtod(m, struct ip *); 858 ip->ip_len += hlen; 859 /* 860 * Jump backwards to complete processing of the 861 * packet. We do not need to clear args.next_hop 862 * as that will not be used again and the cloned packet 863 * doesn't contain a divert packet tag so we won't 864 * re-entry this block. 865 */ 866 goto pass; 867 } 868 #endif 869 870 #ifdef IPSEC 871 /* 872 * enforce IPsec policy checking if we are seeing last header. 873 * note that we do not visit this with protocols with pcb layer 874 * code - like udp/tcp/raw ip. 875 */ 876 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 877 ipsec4_in_reject(m, NULL)) { 878 ipsecstat.in_polvio++; 879 goto bad; 880 } 881 #endif 882 #if FAST_IPSEC 883 /* 884 * enforce IPsec policy checking if we are seeing last header. 885 * note that we do not visit this with protocols with pcb layer 886 * code - like udp/tcp/raw ip. 887 */ 888 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 889 /* 890 * Check if the packet has already had IPsec processing 891 * done. If so, then just pass it along. This tag gets 892 * set during AH, ESP, etc. input handling, before the 893 * packet is returned to the ip input queue for delivery. 894 */ 895 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 896 s = splnet(); 897 if (mtag != NULL) { 898 tdbi = (struct tdb_ident *)(mtag + 1); 899 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 900 } else { 901 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 902 IP_FORWARDING, &error); 903 } 904 if (sp != NULL) { 905 /* 906 * Check security policy against packet attributes. 907 */ 908 error = ipsec_in_reject(sp, m); 909 KEY_FREESP(&sp); 910 } else { 911 /* XXX error stat??? */ 912 error = EINVAL; 913 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 914 goto bad; 915 } 916 splx(s); 917 if (error) 918 goto bad; 919 } 920 #endif /* FAST_IPSEC */ 921 922 /* 923 * Switch out to protocol's input routine. 924 */ 925 ipstat.ips_delivered++; 926 if (args.next_hop && ip->ip_p == IPPROTO_TCP) { 927 /* attach next hop info for TCP */ 928 struct m_tag *mtag = m_tag_get(PACKET_TAG_IPFORWARD, 929 sizeof(struct sockaddr_in *), M_NOWAIT); 930 if (mtag == NULL) 931 goto bad; 932 *(struct sockaddr_in **)(mtag+1) = args.next_hop; 933 m_tag_prepend(m, mtag); 934 } 935 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 936 return; 937 bad: 938 m_freem(m); 939 } 940 941 /* 942 * Take incoming datagram fragment and try to reassemble it into 943 * whole datagram. If a chain for reassembly of this datagram already 944 * exists, then it is given as fp; otherwise have to make a chain. 945 * 946 * When IPDIVERT enabled, keep additional state with each packet that 947 * tells us if we need to divert or tee the packet we're building. 948 * In particular, *divinfo includes the port and TEE flag, 949 * *divert_rule is the number of the matching rule. 950 */ 951 952 static struct mbuf * 953 ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp) 954 { 955 struct ip *ip = mtod(m, struct ip *); 956 register struct mbuf *p, *q, *nq; 957 struct mbuf *t; 958 int hlen = ip->ip_hl << 2; 959 int i, next; 960 u_int8_t ecn, ecn0; 961 962 IPQ_LOCK_ASSERT(); 963 964 /* 965 * Presence of header sizes in mbufs 966 * would confuse code below. 967 */ 968 m->m_data += hlen; 969 m->m_len -= hlen; 970 971 /* 972 * If first fragment to arrive, create a reassembly queue. 973 */ 974 if (fp == NULL) { 975 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 976 goto dropfrag; 977 fp = mtod(t, struct ipq *); 978 #ifdef MAC 979 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 980 m_free(t); 981 goto dropfrag; 982 } 983 mac_create_ipq(m, fp); 984 #endif 985 TAILQ_INSERT_HEAD(head, fp, ipq_list); 986 nipq++; 987 fp->ipq_nfrags = 1; 988 fp->ipq_ttl = IPFRAGTTL; 989 fp->ipq_p = ip->ip_p; 990 fp->ipq_id = ip->ip_id; 991 fp->ipq_src = ip->ip_src; 992 fp->ipq_dst = ip->ip_dst; 993 fp->ipq_frags = m; 994 m->m_nextpkt = NULL; 995 goto inserted; 996 } else { 997 fp->ipq_nfrags++; 998 #ifdef MAC 999 mac_update_ipq(m, fp); 1000 #endif 1001 } 1002 1003 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1004 1005 /* 1006 * Handle ECN by comparing this segment with the first one; 1007 * if CE is set, do not lose CE. 1008 * drop if CE and not-ECT are mixed for the same packet. 1009 */ 1010 ecn = ip->ip_tos & IPTOS_ECN_MASK; 1011 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 1012 if (ecn == IPTOS_ECN_CE) { 1013 if (ecn0 == IPTOS_ECN_NOTECT) 1014 goto dropfrag; 1015 if (ecn0 != IPTOS_ECN_CE) 1016 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 1017 } 1018 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 1019 goto dropfrag; 1020 1021 /* 1022 * Find a segment which begins after this one does. 1023 */ 1024 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1025 if (GETIP(q)->ip_off > ip->ip_off) 1026 break; 1027 1028 /* 1029 * If there is a preceding segment, it may provide some of 1030 * our data already. If so, drop the data from the incoming 1031 * segment. If it provides all of our data, drop us, otherwise 1032 * stick new segment in the proper place. 1033 * 1034 * If some of the data is dropped from the the preceding 1035 * segment, then it's checksum is invalidated. 1036 */ 1037 if (p) { 1038 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1039 if (i > 0) { 1040 if (i >= ip->ip_len) 1041 goto dropfrag; 1042 m_adj(m, i); 1043 m->m_pkthdr.csum_flags = 0; 1044 ip->ip_off += i; 1045 ip->ip_len -= i; 1046 } 1047 m->m_nextpkt = p->m_nextpkt; 1048 p->m_nextpkt = m; 1049 } else { 1050 m->m_nextpkt = fp->ipq_frags; 1051 fp->ipq_frags = m; 1052 } 1053 1054 /* 1055 * While we overlap succeeding segments trim them or, 1056 * if they are completely covered, dequeue them. 1057 */ 1058 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1059 q = nq) { 1060 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1061 if (i < GETIP(q)->ip_len) { 1062 GETIP(q)->ip_len -= i; 1063 GETIP(q)->ip_off += i; 1064 m_adj(q, i); 1065 q->m_pkthdr.csum_flags = 0; 1066 break; 1067 } 1068 nq = q->m_nextpkt; 1069 m->m_nextpkt = nq; 1070 ipstat.ips_fragdropped++; 1071 fp->ipq_nfrags--; 1072 m_freem(q); 1073 } 1074 1075 inserted: 1076 1077 #ifdef IPDIVERT 1078 if (ip->ip_off != 0) { 1079 /* 1080 * Strip any divert information; only the info 1081 * on the first fragment is used/kept. 1082 */ 1083 struct m_tag *mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL); 1084 if (mtag) 1085 m_tag_delete(m, mtag); 1086 } 1087 #endif 1088 1089 /* 1090 * Check for complete reassembly and perform frag per packet 1091 * limiting. 1092 * 1093 * Frag limiting is performed here so that the nth frag has 1094 * a chance to complete the packet before we drop the packet. 1095 * As a result, n+1 frags are actually allowed per packet, but 1096 * only n will ever be stored. (n = maxfragsperpacket.) 1097 * 1098 */ 1099 next = 0; 1100 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1101 if (GETIP(q)->ip_off != next) { 1102 if (fp->ipq_nfrags > maxfragsperpacket) { 1103 ipstat.ips_fragdropped += fp->ipq_nfrags; 1104 ip_freef(head, fp); 1105 } 1106 return (0); 1107 } 1108 next += GETIP(q)->ip_len; 1109 } 1110 /* Make sure the last packet didn't have the IP_MF flag */ 1111 if (p->m_flags & M_FRAG) { 1112 if (fp->ipq_nfrags > maxfragsperpacket) { 1113 ipstat.ips_fragdropped += fp->ipq_nfrags; 1114 ip_freef(head, fp); 1115 } 1116 return (0); 1117 } 1118 1119 /* 1120 * Reassembly is complete. Make sure the packet is a sane size. 1121 */ 1122 q = fp->ipq_frags; 1123 ip = GETIP(q); 1124 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1125 ipstat.ips_toolong++; 1126 ipstat.ips_fragdropped += fp->ipq_nfrags; 1127 ip_freef(head, fp); 1128 return (0); 1129 } 1130 1131 /* 1132 * Concatenate fragments. 1133 */ 1134 m = q; 1135 t = m->m_next; 1136 m->m_next = 0; 1137 m_cat(m, t); 1138 nq = q->m_nextpkt; 1139 q->m_nextpkt = 0; 1140 for (q = nq; q != NULL; q = nq) { 1141 nq = q->m_nextpkt; 1142 q->m_nextpkt = NULL; 1143 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1144 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1145 m_cat(m, q); 1146 } 1147 #ifdef MAC 1148 mac_create_datagram_from_ipq(fp, m); 1149 mac_destroy_ipq(fp); 1150 #endif 1151 1152 /* 1153 * Create header for new ip packet by 1154 * modifying header of first packet; 1155 * dequeue and discard fragment reassembly header. 1156 * Make header visible. 1157 */ 1158 ip->ip_len = next; 1159 ip->ip_src = fp->ipq_src; 1160 ip->ip_dst = fp->ipq_dst; 1161 TAILQ_REMOVE(head, fp, ipq_list); 1162 nipq--; 1163 (void) m_free(dtom(fp)); 1164 m->m_len += (ip->ip_hl << 2); 1165 m->m_data -= (ip->ip_hl << 2); 1166 /* some debugging cruft by sklower, below, will go away soon */ 1167 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1168 m_fixhdr(m); 1169 return (m); 1170 1171 dropfrag: 1172 ipstat.ips_fragdropped++; 1173 if (fp != NULL) 1174 fp->ipq_nfrags--; 1175 m_freem(m); 1176 return (0); 1177 1178 #undef GETIP 1179 } 1180 1181 /* 1182 * Free a fragment reassembly header and all 1183 * associated datagrams. 1184 */ 1185 static void 1186 ip_freef(fhp, fp) 1187 struct ipqhead *fhp; 1188 struct ipq *fp; 1189 { 1190 register struct mbuf *q; 1191 1192 IPQ_LOCK_ASSERT(); 1193 1194 while (fp->ipq_frags) { 1195 q = fp->ipq_frags; 1196 fp->ipq_frags = q->m_nextpkt; 1197 m_freem(q); 1198 } 1199 TAILQ_REMOVE(fhp, fp, ipq_list); 1200 (void) m_free(dtom(fp)); 1201 nipq--; 1202 } 1203 1204 /* 1205 * IP timer processing; 1206 * if a timer expires on a reassembly 1207 * queue, discard it. 1208 */ 1209 void 1210 ip_slowtimo() 1211 { 1212 register struct ipq *fp; 1213 int s = splnet(); 1214 int i; 1215 1216 IPQ_LOCK(); 1217 for (i = 0; i < IPREASS_NHASH; i++) { 1218 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1219 struct ipq *fpp; 1220 1221 fpp = fp; 1222 fp = TAILQ_NEXT(fp, ipq_list); 1223 if(--fpp->ipq_ttl == 0) { 1224 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1225 ip_freef(&ipq[i], fpp); 1226 } 1227 } 1228 } 1229 /* 1230 * If we are over the maximum number of fragments 1231 * (due to the limit being lowered), drain off 1232 * enough to get down to the new limit. 1233 */ 1234 if (maxnipq >= 0 && nipq > maxnipq) { 1235 for (i = 0; i < IPREASS_NHASH; i++) { 1236 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1237 ipstat.ips_fragdropped += 1238 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1239 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1240 } 1241 } 1242 } 1243 IPQ_UNLOCK(); 1244 splx(s); 1245 } 1246 1247 /* 1248 * Drain off all datagram fragments. 1249 */ 1250 void 1251 ip_drain() 1252 { 1253 int i; 1254 1255 IPQ_LOCK(); 1256 for (i = 0; i < IPREASS_NHASH; i++) { 1257 while(!TAILQ_EMPTY(&ipq[i])) { 1258 ipstat.ips_fragdropped += 1259 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1260 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1261 } 1262 } 1263 IPQ_UNLOCK(); 1264 in_rtqdrain(); 1265 } 1266 1267 /* 1268 * Do option processing on a datagram, 1269 * possibly discarding it if bad options are encountered, 1270 * or forwarding it if source-routed. 1271 * The pass argument is used when operating in the IPSTEALTH 1272 * mode to tell what options to process: 1273 * [LS]SRR (pass 0) or the others (pass 1). 1274 * The reason for as many as two passes is that when doing IPSTEALTH, 1275 * non-routing options should be processed only if the packet is for us. 1276 * Returns 1 if packet has been forwarded/freed, 1277 * 0 if the packet should be processed further. 1278 */ 1279 static int 1280 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1281 { 1282 struct ip *ip = mtod(m, struct ip *); 1283 u_char *cp; 1284 struct in_ifaddr *ia; 1285 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1286 struct in_addr *sin, dst; 1287 n_time ntime; 1288 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 1289 1290 dst = ip->ip_dst; 1291 cp = (u_char *)(ip + 1); 1292 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1293 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1294 opt = cp[IPOPT_OPTVAL]; 1295 if (opt == IPOPT_EOL) 1296 break; 1297 if (opt == IPOPT_NOP) 1298 optlen = 1; 1299 else { 1300 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1301 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1302 goto bad; 1303 } 1304 optlen = cp[IPOPT_OLEN]; 1305 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1306 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1307 goto bad; 1308 } 1309 } 1310 switch (opt) { 1311 1312 default: 1313 break; 1314 1315 /* 1316 * Source routing with record. 1317 * Find interface with current destination address. 1318 * If none on this machine then drop if strictly routed, 1319 * or do nothing if loosely routed. 1320 * Record interface address and bring up next address 1321 * component. If strictly routed make sure next 1322 * address is on directly accessible net. 1323 */ 1324 case IPOPT_LSRR: 1325 case IPOPT_SSRR: 1326 #ifdef IPSTEALTH 1327 if (ipstealth && pass > 0) 1328 break; 1329 #endif 1330 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1331 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1332 goto bad; 1333 } 1334 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1335 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1336 goto bad; 1337 } 1338 ipaddr.sin_addr = ip->ip_dst; 1339 ia = (struct in_ifaddr *) 1340 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1341 if (ia == 0) { 1342 if (opt == IPOPT_SSRR) { 1343 type = ICMP_UNREACH; 1344 code = ICMP_UNREACH_SRCFAIL; 1345 goto bad; 1346 } 1347 if (!ip_dosourceroute) 1348 goto nosourcerouting; 1349 /* 1350 * Loose routing, and not at next destination 1351 * yet; nothing to do except forward. 1352 */ 1353 break; 1354 } 1355 off--; /* 0 origin */ 1356 if (off > optlen - (int)sizeof(struct in_addr)) { 1357 /* 1358 * End of source route. Should be for us. 1359 */ 1360 if (!ip_acceptsourceroute) 1361 goto nosourcerouting; 1362 save_rte(cp, ip->ip_src); 1363 break; 1364 } 1365 #ifdef IPSTEALTH 1366 if (ipstealth) 1367 goto dropit; 1368 #endif 1369 if (!ip_dosourceroute) { 1370 if (ipforwarding) { 1371 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1372 /* 1373 * Acting as a router, so generate ICMP 1374 */ 1375 nosourcerouting: 1376 strcpy(buf, inet_ntoa(ip->ip_dst)); 1377 log(LOG_WARNING, 1378 "attempted source route from %s to %s\n", 1379 inet_ntoa(ip->ip_src), buf); 1380 type = ICMP_UNREACH; 1381 code = ICMP_UNREACH_SRCFAIL; 1382 goto bad; 1383 } else { 1384 /* 1385 * Not acting as a router, so silently drop. 1386 */ 1387 #ifdef IPSTEALTH 1388 dropit: 1389 #endif 1390 ipstat.ips_cantforward++; 1391 m_freem(m); 1392 return (1); 1393 } 1394 } 1395 1396 /* 1397 * locate outgoing interface 1398 */ 1399 (void)memcpy(&ipaddr.sin_addr, cp + off, 1400 sizeof(ipaddr.sin_addr)); 1401 1402 if (opt == IPOPT_SSRR) { 1403 #define INA struct in_ifaddr * 1404 #define SA struct sockaddr * 1405 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1406 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1407 } else 1408 ia = ip_rtaddr(ipaddr.sin_addr); 1409 if (ia == 0) { 1410 type = ICMP_UNREACH; 1411 code = ICMP_UNREACH_SRCFAIL; 1412 goto bad; 1413 } 1414 ip->ip_dst = ipaddr.sin_addr; 1415 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1416 sizeof(struct in_addr)); 1417 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1418 /* 1419 * Let ip_intr's mcast routing check handle mcast pkts 1420 */ 1421 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1422 break; 1423 1424 case IPOPT_RR: 1425 #ifdef IPSTEALTH 1426 if (ipstealth && pass == 0) 1427 break; 1428 #endif 1429 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1430 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1431 goto bad; 1432 } 1433 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1434 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1435 goto bad; 1436 } 1437 /* 1438 * If no space remains, ignore. 1439 */ 1440 off--; /* 0 origin */ 1441 if (off > optlen - (int)sizeof(struct in_addr)) 1442 break; 1443 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1444 sizeof(ipaddr.sin_addr)); 1445 /* 1446 * locate outgoing interface; if we're the destination, 1447 * use the incoming interface (should be same). 1448 */ 1449 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1450 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1451 type = ICMP_UNREACH; 1452 code = ICMP_UNREACH_HOST; 1453 goto bad; 1454 } 1455 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1456 sizeof(struct in_addr)); 1457 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1458 break; 1459 1460 case IPOPT_TS: 1461 #ifdef IPSTEALTH 1462 if (ipstealth && pass == 0) 1463 break; 1464 #endif 1465 code = cp - (u_char *)ip; 1466 if (optlen < 4 || optlen > 40) { 1467 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1468 goto bad; 1469 } 1470 if ((off = cp[IPOPT_OFFSET]) < 5) { 1471 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1472 goto bad; 1473 } 1474 if (off > optlen - (int)sizeof(int32_t)) { 1475 cp[IPOPT_OFFSET + 1] += (1 << 4); 1476 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1477 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1478 goto bad; 1479 } 1480 break; 1481 } 1482 off--; /* 0 origin */ 1483 sin = (struct in_addr *)(cp + off); 1484 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1485 1486 case IPOPT_TS_TSONLY: 1487 break; 1488 1489 case IPOPT_TS_TSANDADDR: 1490 if (off + sizeof(n_time) + 1491 sizeof(struct in_addr) > optlen) { 1492 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1493 goto bad; 1494 } 1495 ipaddr.sin_addr = dst; 1496 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1497 m->m_pkthdr.rcvif); 1498 if (ia == 0) 1499 continue; 1500 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1501 sizeof(struct in_addr)); 1502 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1503 off += sizeof(struct in_addr); 1504 break; 1505 1506 case IPOPT_TS_PRESPEC: 1507 if (off + sizeof(n_time) + 1508 sizeof(struct in_addr) > optlen) { 1509 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1510 goto bad; 1511 } 1512 (void)memcpy(&ipaddr.sin_addr, sin, 1513 sizeof(struct in_addr)); 1514 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1515 continue; 1516 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1517 off += sizeof(struct in_addr); 1518 break; 1519 1520 default: 1521 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1522 goto bad; 1523 } 1524 ntime = iptime(); 1525 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1526 cp[IPOPT_OFFSET] += sizeof(n_time); 1527 } 1528 } 1529 if (forward && ipforwarding) { 1530 ip_forward(m, 1, next_hop); 1531 return (1); 1532 } 1533 return (0); 1534 bad: 1535 icmp_error(m, type, code, 0, 0); 1536 ipstat.ips_badoptions++; 1537 return (1); 1538 } 1539 1540 /* 1541 * Given address of next destination (final or next hop), 1542 * return internet address info of interface to be used to get there. 1543 */ 1544 struct in_ifaddr * 1545 ip_rtaddr(dst) 1546 struct in_addr dst; 1547 { 1548 struct route sro; 1549 struct sockaddr_in *sin; 1550 struct in_ifaddr *ifa; 1551 1552 bzero(&sro, sizeof(sro)); 1553 sin = (struct sockaddr_in *)&sro.ro_dst; 1554 sin->sin_family = AF_INET; 1555 sin->sin_len = sizeof(*sin); 1556 sin->sin_addr = dst; 1557 rtalloc_ign(&sro, RTF_CLONING); 1558 1559 if (sro.ro_rt == NULL) 1560 return ((struct in_ifaddr *)0); 1561 1562 ifa = ifatoia(sro.ro_rt->rt_ifa); 1563 RTFREE(sro.ro_rt); 1564 return ifa; 1565 } 1566 1567 /* 1568 * Save incoming source route for use in replies, 1569 * to be picked up later by ip_srcroute if the receiver is interested. 1570 */ 1571 static void 1572 save_rte(option, dst) 1573 u_char *option; 1574 struct in_addr dst; 1575 { 1576 unsigned olen; 1577 1578 olen = option[IPOPT_OLEN]; 1579 #ifdef DIAGNOSTIC 1580 if (ipprintfs) 1581 printf("save_rte: olen %d\n", olen); 1582 #endif 1583 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1584 return; 1585 bcopy(option, ip_srcrt.srcopt, olen); 1586 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1587 ip_srcrt.dst = dst; 1588 } 1589 1590 /* 1591 * Retrieve incoming source route for use in replies, 1592 * in the same form used by setsockopt. 1593 * The first hop is placed before the options, will be removed later. 1594 */ 1595 struct mbuf * 1596 ip_srcroute() 1597 { 1598 register struct in_addr *p, *q; 1599 register struct mbuf *m; 1600 1601 if (ip_nhops == 0) 1602 return ((struct mbuf *)0); 1603 m = m_get(M_DONTWAIT, MT_HEADER); 1604 if (m == 0) 1605 return ((struct mbuf *)0); 1606 1607 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1608 1609 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1610 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1611 OPTSIZ; 1612 #ifdef DIAGNOSTIC 1613 if (ipprintfs) 1614 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1615 #endif 1616 1617 /* 1618 * First save first hop for return route 1619 */ 1620 p = &ip_srcrt.route[ip_nhops - 1]; 1621 *(mtod(m, struct in_addr *)) = *p--; 1622 #ifdef DIAGNOSTIC 1623 if (ipprintfs) 1624 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1625 #endif 1626 1627 /* 1628 * Copy option fields and padding (nop) to mbuf. 1629 */ 1630 ip_srcrt.nop = IPOPT_NOP; 1631 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1632 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1633 &ip_srcrt.nop, OPTSIZ); 1634 q = (struct in_addr *)(mtod(m, caddr_t) + 1635 sizeof(struct in_addr) + OPTSIZ); 1636 #undef OPTSIZ 1637 /* 1638 * Record return path as an IP source route, 1639 * reversing the path (pointers are now aligned). 1640 */ 1641 while (p >= ip_srcrt.route) { 1642 #ifdef DIAGNOSTIC 1643 if (ipprintfs) 1644 printf(" %lx", (u_long)ntohl(q->s_addr)); 1645 #endif 1646 *q++ = *p--; 1647 } 1648 /* 1649 * Last hop goes to final destination. 1650 */ 1651 *q = ip_srcrt.dst; 1652 #ifdef DIAGNOSTIC 1653 if (ipprintfs) 1654 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1655 #endif 1656 return (m); 1657 } 1658 1659 /* 1660 * Strip out IP options, at higher 1661 * level protocol in the kernel. 1662 * Second argument is buffer to which options 1663 * will be moved, and return value is their length. 1664 * XXX should be deleted; last arg currently ignored. 1665 */ 1666 void 1667 ip_stripoptions(m, mopt) 1668 register struct mbuf *m; 1669 struct mbuf *mopt; 1670 { 1671 register int i; 1672 struct ip *ip = mtod(m, struct ip *); 1673 register caddr_t opts; 1674 int olen; 1675 1676 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1677 opts = (caddr_t)(ip + 1); 1678 i = m->m_len - (sizeof (struct ip) + olen); 1679 bcopy(opts + olen, opts, (unsigned)i); 1680 m->m_len -= olen; 1681 if (m->m_flags & M_PKTHDR) 1682 m->m_pkthdr.len -= olen; 1683 ip->ip_v = IPVERSION; 1684 ip->ip_hl = sizeof(struct ip) >> 2; 1685 } 1686 1687 u_char inetctlerrmap[PRC_NCMDS] = { 1688 0, 0, 0, 0, 1689 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1690 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1691 EMSGSIZE, EHOSTUNREACH, 0, 0, 1692 0, 0, EHOSTUNREACH, 0, 1693 ENOPROTOOPT, ECONNREFUSED 1694 }; 1695 1696 /* 1697 * Forward a packet. If some error occurs return the sender 1698 * an icmp packet. Note we can't always generate a meaningful 1699 * icmp message because icmp doesn't have a large enough repertoire 1700 * of codes and types. 1701 * 1702 * If not forwarding, just drop the packet. This could be confusing 1703 * if ipforwarding was zero but some routing protocol was advancing 1704 * us as a gateway to somewhere. However, we must let the routing 1705 * protocol deal with that. 1706 * 1707 * The srcrt parameter indicates whether the packet is being forwarded 1708 * via a source route. 1709 */ 1710 static void 1711 ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop) 1712 { 1713 struct ip *ip = mtod(m, struct ip *); 1714 struct in_ifaddr *ia; 1715 int error, type = 0, code = 0; 1716 struct mbuf *mcopy; 1717 n_long dest; 1718 struct in_addr pkt_dst; 1719 struct ifnet *destifp; 1720 #if defined(IPSEC) || defined(FAST_IPSEC) 1721 struct ifnet dummyifp; 1722 #endif 1723 1724 /* 1725 * Cache the destination address of the packet; this may be 1726 * changed by use of 'ipfw fwd'. 1727 */ 1728 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 1729 1730 #ifdef DIAGNOSTIC 1731 if (ipprintfs) 1732 printf("forward: src %lx dst %lx ttl %x\n", 1733 (u_long)ip->ip_src.s_addr, (u_long)pkt_dst.s_addr, 1734 ip->ip_ttl); 1735 #endif 1736 1737 1738 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(pkt_dst) == 0) { 1739 ipstat.ips_cantforward++; 1740 m_freem(m); 1741 return; 1742 } 1743 #ifdef IPSTEALTH 1744 if (!ipstealth) { 1745 #endif 1746 if (ip->ip_ttl <= IPTTLDEC) { 1747 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1748 0, 0); 1749 return; 1750 } 1751 #ifdef IPSTEALTH 1752 } 1753 #endif 1754 1755 if ((ia = ip_rtaddr(pkt_dst)) == 0) { 1756 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1757 return; 1758 } 1759 1760 /* 1761 * Save the IP header and at most 8 bytes of the payload, 1762 * in case we need to generate an ICMP message to the src. 1763 * 1764 * XXX this can be optimized a lot by saving the data in a local 1765 * buffer on the stack (72 bytes at most), and only allocating the 1766 * mbuf if really necessary. The vast majority of the packets 1767 * are forwarded without having to send an ICMP back (either 1768 * because unnecessary, or because rate limited), so we are 1769 * really we are wasting a lot of work here. 1770 * 1771 * We don't use m_copy() because it might return a reference 1772 * to a shared cluster. Both this function and ip_output() 1773 * assume exclusive access to the IP header in `m', so any 1774 * data in a cluster may change before we reach icmp_error(). 1775 */ 1776 MGET(mcopy, M_DONTWAIT, m->m_type); 1777 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1778 /* 1779 * It's probably ok if the pkthdr dup fails (because 1780 * the deep copy of the tag chain failed), but for now 1781 * be conservative and just discard the copy since 1782 * code below may some day want the tags. 1783 */ 1784 m_free(mcopy); 1785 mcopy = NULL; 1786 } 1787 if (mcopy != NULL) { 1788 mcopy->m_len = imin((ip->ip_hl << 2) + 8, 1789 (int)ip->ip_len); 1790 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1791 } 1792 1793 #ifdef IPSTEALTH 1794 if (!ipstealth) { 1795 #endif 1796 ip->ip_ttl -= IPTTLDEC; 1797 #ifdef IPSTEALTH 1798 } 1799 #endif 1800 1801 /* 1802 * If forwarding packet using same interface that it came in on, 1803 * perhaps should send a redirect to sender to shortcut a hop. 1804 * Only send redirect if source is sending directly to us, 1805 * and if packet was not source routed (or has any options). 1806 * Also, don't send redirect if forwarding using a default route 1807 * or a route modified by a redirect. 1808 */ 1809 dest = 0; 1810 if (ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1811 struct sockaddr_in *sin; 1812 struct route ro; 1813 struct rtentry *rt; 1814 1815 bzero(&ro, sizeof(ro)); 1816 sin = (struct sockaddr_in *)&ro.ro_dst; 1817 sin->sin_family = AF_INET; 1818 sin->sin_len = sizeof(*sin); 1819 sin->sin_addr = pkt_dst; 1820 rtalloc_ign(&ro, RTF_CLONING); 1821 1822 rt = ro.ro_rt; 1823 1824 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1825 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1826 ipsendredirects && !srcrt && !next_hop) { 1827 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1828 u_long src = ntohl(ip->ip_src.s_addr); 1829 1830 if (RTA(rt) && 1831 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1832 if (rt->rt_flags & RTF_GATEWAY) 1833 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1834 else 1835 dest = pkt_dst.s_addr; 1836 /* Router requirements says to only send host redirects */ 1837 type = ICMP_REDIRECT; 1838 code = ICMP_REDIRECT_HOST; 1839 #ifdef DIAGNOSTIC 1840 if (ipprintfs) 1841 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1842 #endif 1843 } 1844 } 1845 if (rt) 1846 RTFREE(rt); 1847 } 1848 1849 if (next_hop) { 1850 struct m_tag *mtag = m_tag_get(PACKET_TAG_IPFORWARD, 1851 sizeof(struct sockaddr_in *), M_NOWAIT); 1852 if (mtag == NULL) { 1853 m_freem(m); 1854 return; 1855 } 1856 *(struct sockaddr_in **)(mtag+1) = next_hop; 1857 m_tag_prepend(m, mtag); 1858 } 1859 error = ip_output(m, (struct mbuf *)0, NULL, IP_FORWARDING, 0, NULL); 1860 if (error) 1861 ipstat.ips_cantforward++; 1862 else { 1863 ipstat.ips_forward++; 1864 if (type) 1865 ipstat.ips_redirectsent++; 1866 else { 1867 if (mcopy) 1868 m_freem(mcopy); 1869 return; 1870 } 1871 } 1872 if (mcopy == NULL) 1873 return; 1874 destifp = NULL; 1875 1876 switch (error) { 1877 1878 case 0: /* forwarded, but need redirect */ 1879 /* type, code set above */ 1880 break; 1881 1882 case ENETUNREACH: /* shouldn't happen, checked above */ 1883 case EHOSTUNREACH: 1884 case ENETDOWN: 1885 case EHOSTDOWN: 1886 default: 1887 type = ICMP_UNREACH; 1888 code = ICMP_UNREACH_HOST; 1889 break; 1890 1891 case EMSGSIZE: 1892 type = ICMP_UNREACH; 1893 code = ICMP_UNREACH_NEEDFRAG; 1894 #if defined(IPSEC) || defined(FAST_IPSEC) 1895 /* 1896 * If the packet is routed over IPsec tunnel, tell the 1897 * originator the tunnel MTU. 1898 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1899 * XXX quickhack!!! 1900 */ 1901 { 1902 struct secpolicy *sp = NULL; 1903 int ipsecerror; 1904 int ipsechdr; 1905 struct route *ro; 1906 1907 #ifdef IPSEC 1908 sp = ipsec4_getpolicybyaddr(mcopy, 1909 IPSEC_DIR_OUTBOUND, 1910 IP_FORWARDING, 1911 &ipsecerror); 1912 #else /* FAST_IPSEC */ 1913 sp = ipsec_getpolicybyaddr(mcopy, 1914 IPSEC_DIR_OUTBOUND, 1915 IP_FORWARDING, 1916 &ipsecerror); 1917 #endif 1918 if (sp != NULL) { 1919 /* count IPsec header size */ 1920 ipsechdr = ipsec4_hdrsiz(mcopy, 1921 IPSEC_DIR_OUTBOUND, 1922 NULL); 1923 1924 /* 1925 * find the correct route for outer IPv4 1926 * header, compute tunnel MTU. 1927 * 1928 * XXX BUG ALERT 1929 * The "dummyifp" code relies upon the fact 1930 * that icmp_error() touches only ifp->if_mtu. 1931 */ 1932 /*XXX*/ 1933 destifp = NULL; 1934 if (sp->req != NULL 1935 && sp->req->sav != NULL 1936 && sp->req->sav->sah != NULL) { 1937 ro = &sp->req->sav->sah->sa_route; 1938 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1939 dummyifp.if_mtu = 1940 ro->ro_rt->rt_ifp->if_mtu; 1941 dummyifp.if_mtu -= ipsechdr; 1942 destifp = &dummyifp; 1943 } 1944 } 1945 1946 #ifdef IPSEC 1947 key_freesp(sp); 1948 #else /* FAST_IPSEC */ 1949 KEY_FREESP(&sp); 1950 #endif 1951 ipstat.ips_cantfrag++; 1952 break; 1953 } else 1954 #endif /*IPSEC || FAST_IPSEC*/ 1955 destifp = ia->ia_ifp; 1956 #if defined(IPSEC) || defined(FAST_IPSEC) 1957 } 1958 #endif /*IPSEC || FAST_IPSEC*/ 1959 ipstat.ips_cantfrag++; 1960 break; 1961 1962 case ENOBUFS: 1963 /* 1964 * A router should not generate ICMP_SOURCEQUENCH as 1965 * required in RFC1812 Requirements for IP Version 4 Routers. 1966 * Source quench could be a big problem under DoS attacks, 1967 * or if the underlying interface is rate-limited. 1968 * Those who need source quench packets may re-enable them 1969 * via the net.inet.ip.sendsourcequench sysctl. 1970 */ 1971 if (ip_sendsourcequench == 0) { 1972 m_freem(mcopy); 1973 return; 1974 } else { 1975 type = ICMP_SOURCEQUENCH; 1976 code = 0; 1977 } 1978 break; 1979 1980 case EACCES: /* ipfw denied packet */ 1981 m_freem(mcopy); 1982 return; 1983 } 1984 icmp_error(mcopy, type, code, dest, destifp); 1985 } 1986 1987 void 1988 ip_savecontrol(inp, mp, ip, m) 1989 register struct inpcb *inp; 1990 register struct mbuf **mp; 1991 register struct ip *ip; 1992 register struct mbuf *m; 1993 { 1994 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1995 struct bintime bt; 1996 1997 bintime(&bt); 1998 if (inp->inp_socket->so_options & SO_BINTIME) { 1999 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 2000 SCM_BINTIME, SOL_SOCKET); 2001 if (*mp) 2002 mp = &(*mp)->m_next; 2003 } 2004 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2005 struct timeval tv; 2006 2007 bintime2timeval(&bt, &tv); 2008 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2009 SCM_TIMESTAMP, SOL_SOCKET); 2010 if (*mp) 2011 mp = &(*mp)->m_next; 2012 } 2013 } 2014 if (inp->inp_flags & INP_RECVDSTADDR) { 2015 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2016 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2017 if (*mp) 2018 mp = &(*mp)->m_next; 2019 } 2020 if (inp->inp_flags & INP_RECVTTL) { 2021 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2022 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2023 if (*mp) 2024 mp = &(*mp)->m_next; 2025 } 2026 #ifdef notyet 2027 /* XXX 2028 * Moving these out of udp_input() made them even more broken 2029 * than they already were. 2030 */ 2031 /* options were tossed already */ 2032 if (inp->inp_flags & INP_RECVOPTS) { 2033 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2034 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2035 if (*mp) 2036 mp = &(*mp)->m_next; 2037 } 2038 /* ip_srcroute doesn't do what we want here, need to fix */ 2039 if (inp->inp_flags & INP_RECVRETOPTS) { 2040 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2041 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2042 if (*mp) 2043 mp = &(*mp)->m_next; 2044 } 2045 #endif 2046 if (inp->inp_flags & INP_RECVIF) { 2047 struct ifnet *ifp; 2048 struct sdlbuf { 2049 struct sockaddr_dl sdl; 2050 u_char pad[32]; 2051 } sdlbuf; 2052 struct sockaddr_dl *sdp; 2053 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2054 2055 if (((ifp = m->m_pkthdr.rcvif)) 2056 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2057 sdp = (struct sockaddr_dl *) 2058 (ifaddr_byindex(ifp->if_index)->ifa_addr); 2059 /* 2060 * Change our mind and don't try copy. 2061 */ 2062 if ((sdp->sdl_family != AF_LINK) 2063 || (sdp->sdl_len > sizeof(sdlbuf))) { 2064 goto makedummy; 2065 } 2066 bcopy(sdp, sdl2, sdp->sdl_len); 2067 } else { 2068 makedummy: 2069 sdl2->sdl_len 2070 = offsetof(struct sockaddr_dl, sdl_data[0]); 2071 sdl2->sdl_family = AF_LINK; 2072 sdl2->sdl_index = 0; 2073 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2074 } 2075 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2076 IP_RECVIF, IPPROTO_IP); 2077 if (*mp) 2078 mp = &(*mp)->m_next; 2079 } 2080 } 2081 2082 /* 2083 * XXX these routines are called from the upper part of the kernel. 2084 * They need to be locked when we remove Giant. 2085 * 2086 * They could also be moved to ip_mroute.c, since all the RSVP 2087 * handling is done there already. 2088 */ 2089 static int ip_rsvp_on; 2090 struct socket *ip_rsvpd; 2091 int 2092 ip_rsvp_init(struct socket *so) 2093 { 2094 if (so->so_type != SOCK_RAW || 2095 so->so_proto->pr_protocol != IPPROTO_RSVP) 2096 return EOPNOTSUPP; 2097 2098 if (ip_rsvpd != NULL) 2099 return EADDRINUSE; 2100 2101 ip_rsvpd = so; 2102 /* 2103 * This may seem silly, but we need to be sure we don't over-increment 2104 * the RSVP counter, in case something slips up. 2105 */ 2106 if (!ip_rsvp_on) { 2107 ip_rsvp_on = 1; 2108 rsvp_on++; 2109 } 2110 2111 return 0; 2112 } 2113 2114 int 2115 ip_rsvp_done(void) 2116 { 2117 ip_rsvpd = NULL; 2118 /* 2119 * This may seem silly, but we need to be sure we don't over-decrement 2120 * the RSVP counter, in case something slips up. 2121 */ 2122 if (ip_rsvp_on) { 2123 ip_rsvp_on = 0; 2124 rsvp_on--; 2125 } 2126 return 0; 2127 } 2128 2129 void 2130 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 2131 { 2132 if (rsvp_input_p) { /* call the real one if loaded */ 2133 rsvp_input_p(m, off); 2134 return; 2135 } 2136 2137 /* Can still get packets with rsvp_on = 0 if there is a local member 2138 * of the group to which the RSVP packet is addressed. But in this 2139 * case we want to throw the packet away. 2140 */ 2141 2142 if (!rsvp_on) { 2143 m_freem(m); 2144 return; 2145 } 2146 2147 if (ip_rsvpd != NULL) { 2148 rip_input(m, off); 2149 return; 2150 } 2151 /* Drop the packet */ 2152 m_freem(m); 2153 } 2154