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: src/sys/netinet/ip_input.c,v 1.130.2.52 2003/03/07 07:01:28 silby Exp $ 35 * $DragonFly: src/sys/netinet/ip_input.c,v 1.8 2003/11/08 07:57:51 dillon Exp $ 36 */ 37 38 #define _IP_VHL 39 40 #include "opt_bootp.h" 41 #include "opt_ipfw.h" 42 #include "opt_ipdn.h" 43 #include "opt_ipdivert.h" 44 #include "opt_ipfilter.h" 45 #include "opt_ipstealth.h" 46 #include "opt_ipsec.h" 47 #include "opt_random_ip_id.h" 48 49 #include <sys/param.h> 50 #include <sys/systm.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/if.h> 62 #include <net/if_types.h> 63 #include <net/if_var.h> 64 #include <net/if_dl.h> 65 #include <net/route.h> 66 #include <net/netisr.h> 67 #include <net/intrq.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 <netinet/ipprotosw.h> 79 80 #include <sys/socketvar.h> 81 82 #include <net/ipfw/ip_fw.h> 83 #include <net/dummynet/ip_dummynet.h> 84 85 #ifdef IPSEC 86 #include <netinet6/ipsec.h> 87 #include <netproto/key/key.h> 88 #endif 89 90 #ifdef FAST_IPSEC 91 #include <netipsec/ipsec.h> 92 #include <netipsec/key.h> 93 #endif 94 95 int rsvp_on = 0; 96 static int ip_rsvp_on; 97 struct socket *ip_rsvpd; 98 99 int ipforwarding = 0; 100 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 101 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 102 103 static int ipsendredirects = 1; /* XXX */ 104 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 105 &ipsendredirects, 0, "Enable sending IP redirects"); 106 107 int ip_defttl = IPDEFTTL; 108 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 109 &ip_defttl, 0, "Maximum TTL on IP packets"); 110 111 static int ip_dosourceroute = 0; 112 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 113 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 114 115 static int ip_acceptsourceroute = 0; 116 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 117 CTLFLAG_RW, &ip_acceptsourceroute, 0, 118 "Enable accepting source routed IP packets"); 119 120 static int ip_keepfaith = 0; 121 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 122 &ip_keepfaith, 0, 123 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 124 125 static int nipq = 0; /* total # of reass queues */ 126 static int maxnipq; 127 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 128 &maxnipq, 0, 129 "Maximum number of IPv4 fragment reassembly queue entries"); 130 131 static int maxfragsperpacket; 132 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 133 &maxfragsperpacket, 0, 134 "Maximum number of IPv4 fragments allowed per packet"); 135 136 static int ip_sendsourcequench = 0; 137 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 138 &ip_sendsourcequench, 0, 139 "Enable the transmission of source quench packets"); 140 141 /* 142 * XXX - Setting ip_checkinterface mostly implements the receive side of 143 * the Strong ES model described in RFC 1122, but since the routing table 144 * and transmit implementation do not implement the Strong ES model, 145 * setting this to 1 results in an odd hybrid. 146 * 147 * XXX - ip_checkinterface currently must be disabled if you use ipnat 148 * to translate the destination address to another local interface. 149 * 150 * XXX - ip_checkinterface must be disabled if you add IP aliases 151 * to the loopback interface instead of the interface where the 152 * packets for those addresses are received. 153 */ 154 static int ip_checkinterface = 0; 155 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 156 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 157 158 #ifdef DIAGNOSTIC 159 static int ipprintfs = 0; 160 #endif 161 162 static struct ifqueue ipintrq; 163 static int ipqmaxlen = IFQ_MAXLEN; 164 165 extern struct domain inetdomain; 166 extern struct ipprotosw inetsw[]; 167 u_char ip_protox[IPPROTO_MAX]; 168 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 169 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 170 u_long in_ifaddrhmask; /* mask for hash table */ 171 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 172 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 173 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 174 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 175 176 struct ipstat ipstat; 177 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 178 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 179 180 /* Packet reassembly stuff */ 181 #define IPREASS_NHASH_LOG2 6 182 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 183 #define IPREASS_HMASK (IPREASS_NHASH - 1) 184 #define IPREASS_HASH(x,y) \ 185 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 186 187 static struct ipq ipq[IPREASS_NHASH]; 188 const int ipintrq_present = 1; 189 190 #ifdef IPCTL_DEFMTU 191 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 192 &ip_mtu, 0, "Default MTU"); 193 #endif 194 195 #ifdef IPSTEALTH 196 static int ipstealth = 0; 197 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 198 &ipstealth, 0, ""); 199 #endif 200 201 202 /* Firewall hooks */ 203 ip_fw_chk_t *ip_fw_chk_ptr; 204 int fw_enable = 1 ; 205 int fw_one_pass = 1; 206 207 /* Dummynet hooks */ 208 ip_dn_io_t *ip_dn_io_ptr; 209 210 int (*fr_checkp) (struct ip *, int, struct ifnet *, int, struct mbuf **) = NULL; 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 ipq *); 239 static struct mbuf *ip_reass(struct mbuf *, struct ipq *, 240 struct ipq *, u_int32_t *, u_int16_t *); 241 242 /* 243 * IP initialization: fill in IP protocol switch table. 244 * All protocols not implemented in kernel go to raw IP protocol handler. 245 */ 246 void 247 ip_init() 248 { 249 struct ipprotosw *pr; 250 int i; 251 252 TAILQ_INIT(&in_ifaddrhead); 253 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 254 pr = (struct ipprotosw *)pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 255 if (pr == 0) 256 panic("ip_init"); 257 for (i = 0; i < IPPROTO_MAX; i++) 258 ip_protox[i] = pr - inetsw; 259 for (pr = (struct ipprotosw *)inetdomain.dom_protosw; 260 pr < (struct ipprotosw *)inetdomain.dom_protoswNPROTOSW; pr++) 261 if (pr->pr_domain->dom_family == PF_INET && 262 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 263 ip_protox[pr->pr_protocol] = pr - inetsw; 264 265 for (i = 0; i < IPREASS_NHASH; i++) 266 ipq[i].next = ipq[i].prev = &ipq[i]; 267 268 maxnipq = nmbclusters / 32; 269 maxfragsperpacket = 16; 270 271 #ifndef RANDOM_IP_ID 272 ip_id = time_second & 0xffff; 273 #endif 274 ipintrq.ifq_maxlen = ipqmaxlen; 275 276 netisr_register(NETISR_IP, ip_mport, ip_input); 277 } 278 279 /* 280 * XXX watch out this one. It is perhaps used as a cache for 281 * the most recently used route ? it is cleared in in_addroute() 282 * when a new route is successfully created. 283 */ 284 struct route ipforward_rt; 285 static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 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; 295 struct ipq *fp; 296 struct in_ifaddr *ia = NULL; 297 struct ifaddr *ifa; 298 int i, hlen, checkif; 299 u_short sum; 300 struct in_addr pkt_dst; 301 u_int32_t divert_info = 0; /* packet divert/tee info */ 302 struct ip_fw_args args; 303 #ifdef FAST_IPSEC 304 struct m_tag *mtag; 305 struct tdb_ident *tdbi; 306 struct secpolicy *sp; 307 int s, error; 308 #endif /* FAST_IPSEC */ 309 310 args.eh = NULL; 311 args.oif = NULL; 312 args.rule = NULL; 313 args.divert_rule = 0; /* divert cookie */ 314 args.next_hop = NULL; 315 316 /* Grab info from MT_TAG mbufs prepended to the chain. */ 317 for (; m && m->m_type == MT_TAG; m = m->m_next) { 318 switch(m->_m_tag_id) { 319 default: 320 printf("ip_input: unrecognised MT_TAG tag %d\n", 321 m->_m_tag_id); 322 break; 323 324 case PACKET_TAG_DUMMYNET: 325 args.rule = ((struct dn_pkt *)m)->rule; 326 break; 327 328 case PACKET_TAG_DIVERT: 329 args.divert_rule = (int)m->m_hdr.mh_data & 0xffff; 330 break; 331 332 case PACKET_TAG_IPFORWARD: 333 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 334 break; 335 } 336 } 337 338 KASSERT(m != NULL && (m->m_flags & M_PKTHDR) != 0, 339 ("ip_input: no HDR")); 340 341 if (args.rule) { /* dummynet already filtered us */ 342 ip = mtod(m, struct ip *); 343 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 344 goto iphack ; 345 } 346 347 ipstat.ips_total++; 348 349 if (m->m_pkthdr.len < sizeof(struct ip)) 350 goto tooshort; 351 352 if (m->m_len < sizeof (struct ip) && 353 (m = m_pullup(m, sizeof (struct ip))) == 0) { 354 ipstat.ips_toosmall++; 355 return; 356 } 357 ip = mtod(m, struct ip *); 358 359 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 360 ipstat.ips_badvers++; 361 goto bad; 362 } 363 364 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 365 if (hlen < sizeof(struct ip)) { /* minimum header length */ 366 ipstat.ips_badhlen++; 367 goto bad; 368 } 369 if (hlen > m->m_len) { 370 if ((m = m_pullup(m, hlen)) == 0) { 371 ipstat.ips_badhlen++; 372 return; 373 } 374 ip = mtod(m, struct ip *); 375 } 376 377 /* 127/8 must not appear on wire - RFC1122 */ 378 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 379 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 380 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 381 ipstat.ips_badaddr++; 382 goto bad; 383 } 384 } 385 386 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 387 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 388 } else { 389 if (hlen == sizeof(struct ip)) { 390 sum = in_cksum_hdr(ip); 391 } else { 392 sum = in_cksum(m, hlen); 393 } 394 } 395 if (sum) { 396 ipstat.ips_badsum++; 397 goto bad; 398 } 399 400 /* 401 * Convert fields to host representation. 402 */ 403 ip->ip_len = ntohs(ip->ip_len); 404 if (ip->ip_len < hlen) { 405 ipstat.ips_badlen++; 406 goto bad; 407 } 408 ip->ip_off = ntohs(ip->ip_off); 409 410 /* 411 * Check that the amount of data in the buffers 412 * is as at least much as the IP header would have us expect. 413 * Trim mbufs if longer than we expect. 414 * Drop packet if shorter than we expect. 415 */ 416 if (m->m_pkthdr.len < ip->ip_len) { 417 tooshort: 418 ipstat.ips_tooshort++; 419 goto bad; 420 } 421 if (m->m_pkthdr.len > ip->ip_len) { 422 if (m->m_len == m->m_pkthdr.len) { 423 m->m_len = ip->ip_len; 424 m->m_pkthdr.len = ip->ip_len; 425 } else 426 m_adj(m, ip->ip_len - m->m_pkthdr.len); 427 } 428 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 429 /* 430 * Bypass packet filtering for packets from a tunnel (gif). 431 */ 432 if (ipsec_gethist(m, NULL)) 433 goto pass; 434 #endif 435 436 /* 437 * IpHack's section. 438 * Right now when no processing on packet has done 439 * and it is still fresh out of network we do our black 440 * deals with it. 441 * - Firewall: deny/allow/divert 442 * - Xlate: translate packet's addr/port (NAT). 443 * - Pipe: pass pkt through dummynet. 444 * - Wrap: fake packet's addr/port <unimpl.> 445 * - Encapsulate: put it in another IP and send out. <unimp.> 446 */ 447 448 iphack: 449 /* 450 * Check if we want to allow this packet to be processed. 451 * Consider it to be bad if not. 452 */ 453 if (fr_checkp) { 454 struct mbuf *m1 = m; 455 456 if ((*fr_checkp)(ip, hlen, m->m_pkthdr.rcvif, 0, &m1) || !m1) 457 return; 458 ip = mtod(m = m1, struct ip *); 459 } 460 if (fw_enable && IPFW_LOADED) { 461 /* 462 * If we've been forwarded from the output side, then 463 * skip the firewall a second time 464 */ 465 if (args.next_hop) 466 goto ours; 467 468 args.m = m; 469 i = ip_fw_chk_ptr(&args); 470 m = args.m; 471 472 if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 473 if (m) 474 m_freem(m); 475 return; 476 } 477 ip = mtod(m, struct ip *); /* just in case m changed */ 478 if (i == 0 && args.next_hop == NULL) /* common case */ 479 goto pass; 480 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) { 481 /* Send packet to the appropriate pipe */ 482 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 483 return; 484 } 485 #ifdef IPDIVERT 486 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 487 /* Divert or tee packet */ 488 divert_info = i; 489 goto ours; 490 } 491 #endif 492 if (i == 0 && args.next_hop != NULL) 493 goto pass; 494 /* 495 * if we get here, the packet must be dropped 496 */ 497 m_freem(m); 498 return; 499 } 500 pass: 501 502 /* 503 * Process options and, if not destined for us, 504 * ship it on. ip_dooptions returns 1 when an 505 * error was detected (causing an icmp message 506 * to be sent and the original packet to be freed). 507 */ 508 ip_nhops = 0; /* for source routed packets */ 509 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, args.next_hop)) 510 return; 511 512 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 513 * matter if it is destined to another node, or whether it is 514 * a multicast one, RSVP wants it! and prevents it from being forwarded 515 * anywhere else. Also checks if the rsvp daemon is running before 516 * grabbing the packet. 517 */ 518 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 519 goto ours; 520 521 /* 522 * Check our list of addresses, to see if the packet is for us. 523 * If we don't have any addresses, assume any unicast packet 524 * we receive might be for us (and let the upper layers deal 525 * with it). 526 */ 527 if (TAILQ_EMPTY(&in_ifaddrhead) && 528 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 529 goto ours; 530 531 /* 532 * Cache the destination address of the packet; this may be 533 * changed by use of 'ipfw fwd'. 534 */ 535 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 536 537 /* 538 * Enable a consistency check between the destination address 539 * and the arrival interface for a unicast packet (the RFC 1122 540 * strong ES model) if IP forwarding is disabled and the packet 541 * is not locally generated and the packet is not subject to 542 * 'ipfw fwd'. 543 * 544 * XXX - Checking also should be disabled if the destination 545 * address is ipnat'ed to a different interface. 546 * 547 * XXX - Checking is incompatible with IP aliases added 548 * to the loopback interface instead of the interface where 549 * the packets are received. 550 */ 551 checkif = ip_checkinterface && (ipforwarding == 0) && 552 m->m_pkthdr.rcvif != NULL && 553 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 554 (args.next_hop == NULL); 555 556 /* 557 * Check for exact addresses in the hash bucket. 558 */ 559 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 560 /* 561 * If the address matches, verify that the packet 562 * arrived via the correct interface if checking is 563 * enabled. 564 */ 565 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 566 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 567 goto ours; 568 } 569 /* 570 * Check for broadcast addresses. 571 * 572 * Only accept broadcast packets that arrive via the matching 573 * interface. Reception of forwarded directed broadcasts would 574 * be handled via ip_forward() and ether_output() with the loopback 575 * into the stack for SIMPLEX interfaces handled by ether_output(). 576 */ 577 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 578 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 579 if (ifa->ifa_addr->sa_family != AF_INET) 580 continue; 581 ia = ifatoia(ifa); 582 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 583 pkt_dst.s_addr) 584 goto ours; 585 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 586 goto ours; 587 #ifdef BOOTP_COMPAT 588 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 589 goto ours; 590 #endif 591 } 592 } 593 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 594 struct in_multi *inm; 595 if (ip_mrouter) { 596 /* 597 * If we are acting as a multicast router, all 598 * incoming multicast packets are passed to the 599 * kernel-level multicast forwarding function. 600 * The packet is returned (relatively) intact; if 601 * ip_mforward() returns a non-zero value, the packet 602 * must be discarded, else it may be accepted below. 603 */ 604 if (ip_mforward && 605 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 606 ipstat.ips_cantforward++; 607 m_freem(m); 608 return; 609 } 610 611 /* 612 * The process-level routing daemon needs to receive 613 * all multicast IGMP packets, whether or not this 614 * host belongs to their destination groups. 615 */ 616 if (ip->ip_p == IPPROTO_IGMP) 617 goto ours; 618 ipstat.ips_forward++; 619 } 620 /* 621 * See if we belong to the destination multicast group on the 622 * arrival interface. 623 */ 624 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 625 if (inm == NULL) { 626 ipstat.ips_notmember++; 627 m_freem(m); 628 return; 629 } 630 goto ours; 631 } 632 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 633 goto ours; 634 if (ip->ip_dst.s_addr == INADDR_ANY) 635 goto ours; 636 637 /* 638 * FAITH(Firewall Aided Internet Translator) 639 */ 640 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 641 if (ip_keepfaith) { 642 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 643 goto ours; 644 } 645 m_freem(m); 646 return; 647 } 648 649 /* 650 * Not for us; forward if possible and desirable. 651 */ 652 if (ipforwarding == 0) { 653 ipstat.ips_cantforward++; 654 m_freem(m); 655 } else { 656 #ifdef IPSEC 657 /* 658 * Enforce inbound IPsec SPD. 659 */ 660 if (ipsec4_in_reject(m, NULL)) { 661 ipsecstat.in_polvio++; 662 goto bad; 663 } 664 #endif /* IPSEC */ 665 #ifdef FAST_IPSEC 666 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 667 s = splnet(); 668 if (mtag != NULL) { 669 tdbi = (struct tdb_ident *)(mtag + 1); 670 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 671 } else { 672 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 673 IP_FORWARDING, &error); 674 } 675 if (sp == NULL) { /* NB: can happen if error */ 676 splx(s); 677 /*XXX error stat???*/ 678 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 679 goto bad; 680 } 681 682 /* 683 * Check security policy against packet attributes. 684 */ 685 error = ipsec_in_reject(sp, m); 686 KEY_FREESP(&sp); 687 splx(s); 688 if (error) { 689 ipstat.ips_cantforward++; 690 goto bad; 691 } 692 #endif /* FAST_IPSEC */ 693 ip_forward(m, 0, args.next_hop); 694 } 695 return; 696 697 ours: 698 #ifdef IPSTEALTH 699 /* 700 * IPSTEALTH: Process non-routing options only 701 * if the packet is destined for us. 702 */ 703 if (ipstealth && hlen > sizeof (struct ip) && 704 ip_dooptions(m, 1, args.next_hop)) 705 return; 706 #endif /* IPSTEALTH */ 707 708 /* Count the packet in the ip address stats */ 709 if (ia != NULL) { 710 ia->ia_ifa.if_ipackets++; 711 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 712 } 713 714 /* 715 * If offset or IP_MF are set, must reassemble. 716 * Otherwise, nothing need be done. 717 * (We could look in the reassembly queue to see 718 * if the packet was previously fragmented, 719 * but it's not worth the time; just let them time out.) 720 */ 721 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 722 723 /* If maxnipq is 0, never accept fragments. */ 724 if (maxnipq == 0) { 725 ipstat.ips_fragments++; 726 ipstat.ips_fragdropped++; 727 goto bad; 728 } 729 730 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 731 /* 732 * Look for queue of fragments 733 * of this datagram. 734 */ 735 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 736 if (ip->ip_id == fp->ipq_id && 737 ip->ip_src.s_addr == fp->ipq_src.s_addr && 738 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 739 ip->ip_p == fp->ipq_p) 740 goto found; 741 742 fp = 0; 743 744 /* 745 * Enforce upper bound on number of fragmented packets 746 * for which we attempt reassembly; 747 * If maxnipq is -1, accept all fragments without limitation. 748 */ 749 if ((nipq > maxnipq) && (maxnipq > 0)) { 750 /* 751 * drop something from the tail of the current queue 752 * before proceeding further 753 */ 754 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 755 for (i = 0; i < IPREASS_NHASH; i++) { 756 if (ipq[i].prev != &ipq[i]) { 757 ipstat.ips_fragtimeout += 758 ipq[i].prev->ipq_nfrags; 759 ip_freef(ipq[i].prev); 760 break; 761 } 762 } 763 } else { 764 ipstat.ips_fragtimeout += ipq[sum].prev->ipq_nfrags; 765 ip_freef(ipq[sum].prev); 766 } 767 } 768 found: 769 /* 770 * Adjust ip_len to not reflect header, 771 * convert offset of this to bytes. 772 */ 773 ip->ip_len -= hlen; 774 if (ip->ip_off & IP_MF) { 775 /* 776 * Make sure that fragments have a data length 777 * that's a non-zero multiple of 8 bytes. 778 */ 779 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 780 ipstat.ips_toosmall++; /* XXX */ 781 goto bad; 782 } 783 m->m_flags |= M_FRAG; 784 } else 785 m->m_flags &= ~M_FRAG; 786 ip->ip_off <<= 3; 787 788 /* 789 * Attempt reassembly; if it succeeds, proceed. 790 * ip_reass() will return a different mbuf, and update 791 * the divert info in divert_info and args.divert_rule. 792 */ 793 ipstat.ips_fragments++; 794 m->m_pkthdr.header = ip; 795 m = ip_reass(m, 796 fp, &ipq[sum], &divert_info, &args.divert_rule); 797 if (m == 0) 798 return; 799 ipstat.ips_reassembled++; 800 ip = mtod(m, struct ip *); 801 /* Get the header length of the reassembled packet */ 802 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 803 #ifdef IPDIVERT 804 /* Restore original checksum before diverting packet */ 805 if (divert_info != 0) { 806 ip->ip_len += hlen; 807 ip->ip_len = htons(ip->ip_len); 808 ip->ip_off = htons(ip->ip_off); 809 ip->ip_sum = 0; 810 if (hlen == sizeof(struct ip)) 811 ip->ip_sum = in_cksum_hdr(ip); 812 else 813 ip->ip_sum = in_cksum(m, hlen); 814 ip->ip_off = ntohs(ip->ip_off); 815 ip->ip_len = ntohs(ip->ip_len); 816 ip->ip_len -= hlen; 817 } 818 #endif 819 } else { 820 ip->ip_len -= hlen; 821 } 822 823 #ifdef IPDIVERT 824 /* 825 * Divert or tee packet to the divert protocol if required. 826 */ 827 if (divert_info != 0) { 828 struct mbuf *clone = NULL; 829 830 /* Clone packet if we're doing a 'tee' */ 831 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 832 clone = m_dup(m, M_DONTWAIT); 833 834 /* Restore packet header fields to original values */ 835 ip->ip_len += hlen; 836 ip->ip_len = htons(ip->ip_len); 837 ip->ip_off = htons(ip->ip_off); 838 839 /* Deliver packet to divert input routine */ 840 divert_packet(m, 1, divert_info & 0xffff, args.divert_rule); 841 ipstat.ips_delivered++; 842 843 /* If 'tee', continue with original packet */ 844 if (clone == NULL) 845 return; 846 m = clone; 847 ip = mtod(m, struct ip *); 848 ip->ip_len += hlen; 849 /* 850 * Jump backwards to complete processing of the 851 * packet. But first clear divert_info to avoid 852 * entering this block again. 853 * We do not need to clear args.divert_rule 854 * or args.next_hop as they will not be used. 855 */ 856 divert_info = 0; 857 goto pass; 858 } 859 #endif 860 861 #ifdef IPSEC 862 /* 863 * enforce IPsec policy checking if we are seeing last header. 864 * note that we do not visit this with protocols with pcb layer 865 * code - like udp/tcp/raw ip. 866 */ 867 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 868 ipsec4_in_reject(m, NULL)) { 869 ipsecstat.in_polvio++; 870 goto bad; 871 } 872 #endif 873 #if FAST_IPSEC 874 /* 875 * enforce IPsec policy checking if we are seeing last header. 876 * note that we do not visit this with protocols with pcb layer 877 * code - like udp/tcp/raw ip. 878 */ 879 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 880 /* 881 * Check if the packet has already had IPsec processing 882 * done. If so, then just pass it along. This tag gets 883 * set during AH, ESP, etc. input handling, before the 884 * packet is returned to the ip input queue for delivery. 885 */ 886 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 887 s = splnet(); 888 if (mtag != NULL) { 889 tdbi = (struct tdb_ident *)(mtag + 1); 890 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 891 } else { 892 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 893 IP_FORWARDING, &error); 894 } 895 if (sp != NULL) { 896 /* 897 * Check security policy against packet attributes. 898 */ 899 error = ipsec_in_reject(sp, m); 900 KEY_FREESP(&sp); 901 } else { 902 /* XXX error stat??? */ 903 error = EINVAL; 904 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 905 goto bad; 906 } 907 splx(s); 908 if (error) 909 goto bad; 910 } 911 #endif /* FAST_IPSEC */ 912 913 /* 914 * Switch out to protocol's input routine. 915 * 916 * XXX queue packet to protocol's message port. 917 */ 918 ipstat.ips_delivered++; 919 if (args.next_hop && ip->ip_p == IPPROTO_TCP) { 920 /* TCP needs IPFORWARD info if available */ 921 struct m_hdr tag; 922 923 tag.mh_type = MT_TAG; 924 tag.mh_flags = PACKET_TAG_IPFORWARD; 925 tag.mh_data = (caddr_t)args.next_hop; 926 tag.mh_next = m; 927 928 (*inetsw[ip_protox[ip->ip_p]].pr_input)( 929 (struct mbuf *)&tag, hlen, ip->ip_p); 930 } else { 931 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, ip->ip_p); 932 } 933 return; 934 bad: 935 m_freem(m); 936 } 937 938 /* 939 * Take incoming datagram fragment and try to reassemble it into 940 * whole datagram. If a chain for reassembly of this datagram already 941 * exists, then it is given as fp; otherwise have to make a chain. 942 * 943 * When IPDIVERT enabled, keep additional state with each packet that 944 * tells us if we need to divert or tee the packet we're building. 945 * In particular, *divinfo includes the port and TEE flag, 946 * *divert_rule is the number of the matching rule. 947 */ 948 949 static struct mbuf * 950 ip_reass(struct mbuf *m, struct ipq *fp, struct ipq *where, 951 u_int32_t *divinfo, u_int16_t *divert_rule) 952 { 953 struct ip *ip = mtod(m, struct ip *); 954 struct mbuf *p = 0, *q, *nq; 955 struct mbuf *t; 956 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 957 int i, next; 958 959 /* 960 * Presence of header sizes in mbufs 961 * would confuse code below. 962 */ 963 m->m_data += hlen; 964 m->m_len -= hlen; 965 966 /* 967 * If first fragment to arrive, create a reassembly queue. 968 */ 969 if (fp == 0) { 970 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 971 goto dropfrag; 972 fp = mtod(t, struct ipq *); 973 insque(fp, where); 974 nipq++; 975 fp->ipq_nfrags = 1; 976 fp->ipq_ttl = IPFRAGTTL; 977 fp->ipq_p = ip->ip_p; 978 fp->ipq_id = ip->ip_id; 979 fp->ipq_src = ip->ip_src; 980 fp->ipq_dst = ip->ip_dst; 981 fp->ipq_frags = m; 982 m->m_nextpkt = NULL; 983 #ifdef IPDIVERT 984 fp->ipq_div_info = 0; 985 fp->ipq_div_cookie = 0; 986 #endif 987 goto inserted; 988 } else { 989 fp->ipq_nfrags++; 990 } 991 992 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 993 994 /* 995 * Find a segment which begins after this one does. 996 */ 997 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 998 if (GETIP(q)->ip_off > ip->ip_off) 999 break; 1000 1001 /* 1002 * If there is a preceding segment, it may provide some of 1003 * our data already. If so, drop the data from the incoming 1004 * segment. If it provides all of our data, drop us, otherwise 1005 * stick new segment in the proper place. 1006 * 1007 * If some of the data is dropped from the the preceding 1008 * segment, then it's checksum is invalidated. 1009 */ 1010 if (p) { 1011 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1012 if (i > 0) { 1013 if (i >= ip->ip_len) 1014 goto dropfrag; 1015 m_adj(m, i); 1016 m->m_pkthdr.csum_flags = 0; 1017 ip->ip_off += i; 1018 ip->ip_len -= i; 1019 } 1020 m->m_nextpkt = p->m_nextpkt; 1021 p->m_nextpkt = m; 1022 } else { 1023 m->m_nextpkt = fp->ipq_frags; 1024 fp->ipq_frags = m; 1025 } 1026 1027 /* 1028 * While we overlap succeeding segments trim them or, 1029 * if they are completely covered, dequeue them. 1030 */ 1031 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1032 q = nq) { 1033 i = (ip->ip_off + ip->ip_len) - 1034 GETIP(q)->ip_off; 1035 if (i < GETIP(q)->ip_len) { 1036 GETIP(q)->ip_len -= i; 1037 GETIP(q)->ip_off += i; 1038 m_adj(q, i); 1039 q->m_pkthdr.csum_flags = 0; 1040 break; 1041 } 1042 nq = q->m_nextpkt; 1043 m->m_nextpkt = nq; 1044 ipstat.ips_fragdropped++; 1045 fp->ipq_nfrags--; 1046 m_freem(q); 1047 } 1048 1049 inserted: 1050 1051 #ifdef IPDIVERT 1052 /* 1053 * Transfer firewall instructions to the fragment structure. 1054 * Only trust info in the fragment at offset 0. 1055 */ 1056 if (ip->ip_off == 0) { 1057 fp->ipq_div_info = *divinfo; 1058 fp->ipq_div_cookie = *divert_rule; 1059 } 1060 *divinfo = 0; 1061 *divert_rule = 0; 1062 #endif 1063 1064 /* 1065 * Check for complete reassembly and perform frag per packet 1066 * limiting. 1067 * 1068 * Frag limiting is performed here so that the nth frag has 1069 * a chance to complete the packet before we drop the packet. 1070 * As a result, n+1 frags are actually allowed per packet, but 1071 * only n will ever be stored. (n = maxfragsperpacket.) 1072 * 1073 */ 1074 next = 0; 1075 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1076 if (GETIP(q)->ip_off != next) { 1077 if (fp->ipq_nfrags > maxfragsperpacket) { 1078 ipstat.ips_fragdropped += fp->ipq_nfrags; 1079 ip_freef(fp); 1080 } 1081 return (0); 1082 } 1083 next += GETIP(q)->ip_len; 1084 } 1085 /* Make sure the last packet didn't have the IP_MF flag */ 1086 if (p->m_flags & M_FRAG) { 1087 if (fp->ipq_nfrags > maxfragsperpacket) { 1088 ipstat.ips_fragdropped += fp->ipq_nfrags; 1089 ip_freef(fp); 1090 } 1091 return (0); 1092 } 1093 1094 /* 1095 * Reassembly is complete. Make sure the packet is a sane size. 1096 */ 1097 q = fp->ipq_frags; 1098 ip = GETIP(q); 1099 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1100 ipstat.ips_toolong++; 1101 ipstat.ips_fragdropped += fp->ipq_nfrags; 1102 ip_freef(fp); 1103 return (0); 1104 } 1105 1106 /* 1107 * Concatenate fragments. 1108 */ 1109 m = q; 1110 t = m->m_next; 1111 m->m_next = 0; 1112 m_cat(m, t); 1113 nq = q->m_nextpkt; 1114 q->m_nextpkt = 0; 1115 for (q = nq; q != NULL; q = nq) { 1116 nq = q->m_nextpkt; 1117 q->m_nextpkt = NULL; 1118 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1119 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1120 m_cat(m, q); 1121 } 1122 1123 #ifdef IPDIVERT 1124 /* 1125 * Extract firewall instructions from the fragment structure. 1126 */ 1127 *divinfo = fp->ipq_div_info; 1128 *divert_rule = fp->ipq_div_cookie; 1129 #endif 1130 1131 /* 1132 * Create header for new ip packet by 1133 * modifying header of first packet; 1134 * dequeue and discard fragment reassembly header. 1135 * Make header visible. 1136 */ 1137 ip->ip_len = next; 1138 ip->ip_src = fp->ipq_src; 1139 ip->ip_dst = fp->ipq_dst; 1140 remque(fp); 1141 nipq--; 1142 (void) m_free(dtom(fp)); 1143 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1144 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1145 /* some debugging cruft by sklower, below, will go away soon */ 1146 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1147 int plen = 0; 1148 for (t = m; t; t = t->m_next) 1149 plen += t->m_len; 1150 m->m_pkthdr.len = plen; 1151 } 1152 return (m); 1153 1154 dropfrag: 1155 #ifdef IPDIVERT 1156 *divinfo = 0; 1157 *divert_rule = 0; 1158 #endif 1159 ipstat.ips_fragdropped++; 1160 if (fp != 0) 1161 fp->ipq_nfrags--; 1162 m_freem(m); 1163 return (0); 1164 1165 #undef GETIP 1166 } 1167 1168 /* 1169 * Free a fragment reassembly header and all 1170 * associated datagrams. 1171 */ 1172 static void 1173 ip_freef(fp) 1174 struct ipq *fp; 1175 { 1176 struct mbuf *q; 1177 1178 while (fp->ipq_frags) { 1179 q = fp->ipq_frags; 1180 fp->ipq_frags = q->m_nextpkt; 1181 m_freem(q); 1182 } 1183 remque(fp); 1184 (void) m_free(dtom(fp)); 1185 nipq--; 1186 } 1187 1188 /* 1189 * IP timer processing; 1190 * if a timer expires on a reassembly 1191 * queue, discard it. 1192 */ 1193 void 1194 ip_slowtimo() 1195 { 1196 struct ipq *fp; 1197 int s = splnet(); 1198 int i; 1199 1200 for (i = 0; i < IPREASS_NHASH; i++) { 1201 fp = ipq[i].next; 1202 if (fp == 0) 1203 continue; 1204 while (fp != &ipq[i]) { 1205 --fp->ipq_ttl; 1206 fp = fp->next; 1207 if (fp->prev->ipq_ttl == 0) { 1208 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1209 ip_freef(fp->prev); 1210 } 1211 } 1212 } 1213 /* 1214 * If we are over the maximum number of fragments 1215 * (due to the limit being lowered), drain off 1216 * enough to get down to the new limit. 1217 */ 1218 if (maxnipq >= 0 && nipq > maxnipq) { 1219 for (i = 0; i < IPREASS_NHASH; i++) { 1220 while (nipq > maxnipq && 1221 (ipq[i].next != &ipq[i])) { 1222 ipstat.ips_fragdropped += 1223 ipq[i].next->ipq_nfrags; 1224 ip_freef(ipq[i].next); 1225 } 1226 } 1227 } 1228 ipflow_slowtimo(); 1229 splx(s); 1230 } 1231 1232 /* 1233 * Drain off all datagram fragments. 1234 */ 1235 void 1236 ip_drain() 1237 { 1238 int i; 1239 1240 for (i = 0; i < IPREASS_NHASH; i++) { 1241 while (ipq[i].next != &ipq[i]) { 1242 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1243 ip_freef(ipq[i].next); 1244 } 1245 } 1246 in_rtqdrain(); 1247 } 1248 1249 /* 1250 * Do option processing on a datagram, 1251 * possibly discarding it if bad options are encountered, 1252 * or forwarding it if source-routed. 1253 * The pass argument is used when operating in the IPSTEALTH 1254 * mode to tell what options to process: 1255 * [LS]SRR (pass 0) or the others (pass 1). 1256 * The reason for as many as two passes is that when doing IPSTEALTH, 1257 * non-routing options should be processed only if the packet is for us. 1258 * Returns 1 if packet has been forwarded/freed, 1259 * 0 if the packet should be processed further. 1260 */ 1261 static int 1262 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1263 { 1264 struct ip *ip = mtod(m, struct ip *); 1265 u_char *cp; 1266 struct in_ifaddr *ia; 1267 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1268 struct in_addr *sin, dst; 1269 n_time ntime; 1270 1271 dst = ip->ip_dst; 1272 cp = (u_char *)(ip + 1); 1273 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1274 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1275 opt = cp[IPOPT_OPTVAL]; 1276 if (opt == IPOPT_EOL) 1277 break; 1278 if (opt == IPOPT_NOP) 1279 optlen = 1; 1280 else { 1281 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1282 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1283 goto bad; 1284 } 1285 optlen = cp[IPOPT_OLEN]; 1286 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1287 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1288 goto bad; 1289 } 1290 } 1291 switch (opt) { 1292 1293 default: 1294 break; 1295 1296 /* 1297 * Source routing with record. 1298 * Find interface with current destination address. 1299 * If none on this machine then drop if strictly routed, 1300 * or do nothing if loosely routed. 1301 * Record interface address and bring up next address 1302 * component. If strictly routed make sure next 1303 * address is on directly accessible net. 1304 */ 1305 case IPOPT_LSRR: 1306 case IPOPT_SSRR: 1307 #ifdef IPSTEALTH 1308 if (ipstealth && pass > 0) 1309 break; 1310 #endif 1311 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1312 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1313 goto bad; 1314 } 1315 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1316 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1317 goto bad; 1318 } 1319 ipaddr.sin_addr = ip->ip_dst; 1320 ia = (struct in_ifaddr *) 1321 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1322 if (ia == 0) { 1323 if (opt == IPOPT_SSRR) { 1324 type = ICMP_UNREACH; 1325 code = ICMP_UNREACH_SRCFAIL; 1326 goto bad; 1327 } 1328 if (!ip_dosourceroute) 1329 goto nosourcerouting; 1330 /* 1331 * Loose routing, and not at next destination 1332 * yet; nothing to do except forward. 1333 */ 1334 break; 1335 } 1336 off--; /* 0 origin */ 1337 if (off > optlen - (int)sizeof(struct in_addr)) { 1338 /* 1339 * End of source route. Should be for us. 1340 */ 1341 if (!ip_acceptsourceroute) 1342 goto nosourcerouting; 1343 save_rte(cp, ip->ip_src); 1344 break; 1345 } 1346 #ifdef IPSTEALTH 1347 if (ipstealth) 1348 goto dropit; 1349 #endif 1350 if (!ip_dosourceroute) { 1351 if (ipforwarding) { 1352 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1353 /* 1354 * Acting as a router, so generate ICMP 1355 */ 1356 nosourcerouting: 1357 strcpy(buf, inet_ntoa(ip->ip_dst)); 1358 log(LOG_WARNING, 1359 "attempted source route from %s to %s\n", 1360 inet_ntoa(ip->ip_src), buf); 1361 type = ICMP_UNREACH; 1362 code = ICMP_UNREACH_SRCFAIL; 1363 goto bad; 1364 } else { 1365 /* 1366 * Not acting as a router, so silently drop. 1367 */ 1368 #ifdef IPSTEALTH 1369 dropit: 1370 #endif 1371 ipstat.ips_cantforward++; 1372 m_freem(m); 1373 return (1); 1374 } 1375 } 1376 1377 /* 1378 * locate outgoing interface 1379 */ 1380 (void)memcpy(&ipaddr.sin_addr, cp + off, 1381 sizeof(ipaddr.sin_addr)); 1382 1383 if (opt == IPOPT_SSRR) { 1384 #define INA struct in_ifaddr * 1385 #define SA struct sockaddr * 1386 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1387 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1388 } else 1389 ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt); 1390 if (ia == 0) { 1391 type = ICMP_UNREACH; 1392 code = ICMP_UNREACH_SRCFAIL; 1393 goto bad; 1394 } 1395 ip->ip_dst = ipaddr.sin_addr; 1396 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1397 sizeof(struct in_addr)); 1398 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1399 /* 1400 * Let ip_intr's mcast routing check handle mcast pkts 1401 */ 1402 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1403 break; 1404 1405 case IPOPT_RR: 1406 #ifdef IPSTEALTH 1407 if (ipstealth && pass == 0) 1408 break; 1409 #endif 1410 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1411 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1412 goto bad; 1413 } 1414 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1415 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1416 goto bad; 1417 } 1418 /* 1419 * If no space remains, ignore. 1420 */ 1421 off--; /* 0 origin */ 1422 if (off > optlen - (int)sizeof(struct in_addr)) 1423 break; 1424 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1425 sizeof(ipaddr.sin_addr)); 1426 /* 1427 * locate outgoing interface; if we're the destination, 1428 * use the incoming interface (should be same). 1429 */ 1430 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1431 (ia = ip_rtaddr(ipaddr.sin_addr, 1432 &ipforward_rt)) == 0) { 1433 type = ICMP_UNREACH; 1434 code = ICMP_UNREACH_HOST; 1435 goto bad; 1436 } 1437 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1438 sizeof(struct in_addr)); 1439 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1440 break; 1441 1442 case IPOPT_TS: 1443 #ifdef IPSTEALTH 1444 if (ipstealth && pass == 0) 1445 break; 1446 #endif 1447 code = cp - (u_char *)ip; 1448 if (optlen < 4 || optlen > 40) { 1449 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1450 goto bad; 1451 } 1452 if ((off = cp[IPOPT_OFFSET]) < 5) { 1453 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1454 goto bad; 1455 } 1456 if (off > optlen - (int)sizeof(int32_t)) { 1457 cp[IPOPT_OFFSET + 1] += (1 << 4); 1458 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1459 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1460 goto bad; 1461 } 1462 break; 1463 } 1464 off--; /* 0 origin */ 1465 sin = (struct in_addr *)(cp + off); 1466 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1467 1468 case IPOPT_TS_TSONLY: 1469 break; 1470 1471 case IPOPT_TS_TSANDADDR: 1472 if (off + sizeof(n_time) + 1473 sizeof(struct in_addr) > optlen) { 1474 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1475 goto bad; 1476 } 1477 ipaddr.sin_addr = dst; 1478 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1479 m->m_pkthdr.rcvif); 1480 if (ia == 0) 1481 continue; 1482 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1483 sizeof(struct in_addr)); 1484 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1485 off += sizeof(struct in_addr); 1486 break; 1487 1488 case IPOPT_TS_PRESPEC: 1489 if (off + sizeof(n_time) + 1490 sizeof(struct in_addr) > optlen) { 1491 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1492 goto bad; 1493 } 1494 (void)memcpy(&ipaddr.sin_addr, sin, 1495 sizeof(struct in_addr)); 1496 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1497 continue; 1498 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1499 off += sizeof(struct in_addr); 1500 break; 1501 1502 default: 1503 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1504 goto bad; 1505 } 1506 ntime = iptime(); 1507 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1508 cp[IPOPT_OFFSET] += sizeof(n_time); 1509 } 1510 } 1511 if (forward && ipforwarding) { 1512 ip_forward(m, 1, next_hop); 1513 return (1); 1514 } 1515 return (0); 1516 bad: 1517 icmp_error(m, type, code, 0, 0); 1518 ipstat.ips_badoptions++; 1519 return (1); 1520 } 1521 1522 /* 1523 * Given address of next destination (final or next hop), 1524 * return internet address info of interface to be used to get there. 1525 */ 1526 struct in_ifaddr * 1527 ip_rtaddr(dst, rt) 1528 struct in_addr dst; 1529 struct route *rt; 1530 { 1531 struct sockaddr_in *sin; 1532 1533 sin = (struct sockaddr_in *)&rt->ro_dst; 1534 1535 if (rt->ro_rt == 0 || 1536 dst.s_addr != sin->sin_addr.s_addr) { 1537 if (rt->ro_rt) { 1538 RTFREE(rt->ro_rt); 1539 rt->ro_rt = 0; 1540 } 1541 sin->sin_family = AF_INET; 1542 sin->sin_len = sizeof(*sin); 1543 sin->sin_addr = dst; 1544 1545 rtalloc_ign(rt, RTF_PRCLONING); 1546 } 1547 if (rt->ro_rt == 0) 1548 return ((struct in_ifaddr *)0); 1549 return (ifatoia(rt->ro_rt->rt_ifa)); 1550 } 1551 1552 /* 1553 * Save incoming source route for use in replies, 1554 * to be picked up later by ip_srcroute if the receiver is interested. 1555 */ 1556 void 1557 save_rte(option, dst) 1558 u_char *option; 1559 struct in_addr dst; 1560 { 1561 unsigned olen; 1562 1563 olen = option[IPOPT_OLEN]; 1564 #ifdef DIAGNOSTIC 1565 if (ipprintfs) 1566 printf("save_rte: olen %d\n", olen); 1567 #endif 1568 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1569 return; 1570 bcopy(option, ip_srcrt.srcopt, olen); 1571 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1572 ip_srcrt.dst = dst; 1573 } 1574 1575 /* 1576 * Retrieve incoming source route for use in replies, 1577 * in the same form used by setsockopt. 1578 * The first hop is placed before the options, will be removed later. 1579 */ 1580 struct mbuf * 1581 ip_srcroute() 1582 { 1583 struct in_addr *p, *q; 1584 struct mbuf *m; 1585 1586 if (ip_nhops == 0) 1587 return ((struct mbuf *)0); 1588 m = m_get(M_DONTWAIT, MT_HEADER); 1589 if (m == 0) 1590 return ((struct mbuf *)0); 1591 1592 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1593 1594 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1595 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1596 OPTSIZ; 1597 #ifdef DIAGNOSTIC 1598 if (ipprintfs) 1599 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1600 #endif 1601 1602 /* 1603 * First save first hop for return route 1604 */ 1605 p = &ip_srcrt.route[ip_nhops - 1]; 1606 *(mtod(m, struct in_addr *)) = *p--; 1607 #ifdef DIAGNOSTIC 1608 if (ipprintfs) 1609 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1610 #endif 1611 1612 /* 1613 * Copy option fields and padding (nop) to mbuf. 1614 */ 1615 ip_srcrt.nop = IPOPT_NOP; 1616 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1617 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1618 &ip_srcrt.nop, OPTSIZ); 1619 q = (struct in_addr *)(mtod(m, caddr_t) + 1620 sizeof(struct in_addr) + OPTSIZ); 1621 #undef OPTSIZ 1622 /* 1623 * Record return path as an IP source route, 1624 * reversing the path (pointers are now aligned). 1625 */ 1626 while (p >= ip_srcrt.route) { 1627 #ifdef DIAGNOSTIC 1628 if (ipprintfs) 1629 printf(" %lx", (u_long)ntohl(q->s_addr)); 1630 #endif 1631 *q++ = *p--; 1632 } 1633 /* 1634 * Last hop goes to final destination. 1635 */ 1636 *q = ip_srcrt.dst; 1637 #ifdef DIAGNOSTIC 1638 if (ipprintfs) 1639 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1640 #endif 1641 return (m); 1642 } 1643 1644 /* 1645 * Strip out IP options, at higher 1646 * level protocol in the kernel. 1647 * Second argument is buffer to which options 1648 * will be moved, and return value is their length. 1649 * XXX should be deleted; last arg currently ignored. 1650 */ 1651 void 1652 ip_stripoptions(m, mopt) 1653 struct mbuf *m; 1654 struct mbuf *mopt; 1655 { 1656 int i; 1657 struct ip *ip = mtod(m, struct ip *); 1658 caddr_t opts; 1659 int olen; 1660 1661 olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1662 opts = (caddr_t)(ip + 1); 1663 i = m->m_len - (sizeof (struct ip) + olen); 1664 bcopy(opts + olen, opts, (unsigned)i); 1665 m->m_len -= olen; 1666 if (m->m_flags & M_PKTHDR) 1667 m->m_pkthdr.len -= olen; 1668 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1669 } 1670 1671 u_char inetctlerrmap[PRC_NCMDS] = { 1672 0, 0, 0, 0, 1673 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1674 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1675 EMSGSIZE, EHOSTUNREACH, 0, 0, 1676 0, 0, 0, 0, 1677 ENOPROTOOPT, ECONNREFUSED 1678 }; 1679 1680 /* 1681 * Forward a packet. If some error occurs return the sender 1682 * an icmp packet. Note we can't always generate a meaningful 1683 * icmp message because icmp doesn't have a large enough repertoire 1684 * of codes and types. 1685 * 1686 * If not forwarding, just drop the packet. This could be confusing 1687 * if ipforwarding was zero but some routing protocol was advancing 1688 * us as a gateway to somewhere. However, we must let the routing 1689 * protocol deal with that. 1690 * 1691 * The srcrt parameter indicates whether the packet is being forwarded 1692 * via a source route. 1693 */ 1694 static void 1695 ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop) 1696 { 1697 struct ip *ip = mtod(m, struct ip *); 1698 struct sockaddr_in *sin; 1699 struct rtentry *rt; 1700 int error, type = 0, code = 0; 1701 struct mbuf *mcopy; 1702 n_long dest; 1703 struct in_addr pkt_dst; 1704 struct ifnet *destifp; 1705 #if defined(IPSEC) || defined(FAST_IPSEC) 1706 struct ifnet dummyifp; 1707 #endif 1708 1709 dest = 0; 1710 /* 1711 * Cache the destination address of the packet; this may be 1712 * changed by use of 'ipfw fwd'. 1713 */ 1714 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 1715 1716 #ifdef DIAGNOSTIC 1717 if (ipprintfs) 1718 printf("forward: src %lx dst %lx ttl %x\n", 1719 (u_long)ip->ip_src.s_addr, (u_long)pkt_dst.s_addr, 1720 ip->ip_ttl); 1721 #endif 1722 1723 1724 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(pkt_dst) == 0) { 1725 ipstat.ips_cantforward++; 1726 m_freem(m); 1727 return; 1728 } 1729 #ifdef IPSTEALTH 1730 if (!ipstealth) { 1731 #endif 1732 if (ip->ip_ttl <= IPTTLDEC) { 1733 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1734 dest, 0); 1735 return; 1736 } 1737 #ifdef IPSTEALTH 1738 } 1739 #endif 1740 1741 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1742 if ((rt = ipforward_rt.ro_rt) == 0 || 1743 pkt_dst.s_addr != sin->sin_addr.s_addr) { 1744 if (ipforward_rt.ro_rt) { 1745 RTFREE(ipforward_rt.ro_rt); 1746 ipforward_rt.ro_rt = 0; 1747 } 1748 sin->sin_family = AF_INET; 1749 sin->sin_len = sizeof(*sin); 1750 sin->sin_addr = pkt_dst; 1751 1752 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1753 if (ipforward_rt.ro_rt == 0) { 1754 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1755 return; 1756 } 1757 rt = ipforward_rt.ro_rt; 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_VHL_HL(ip->ip_vhl) << 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 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1810 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1811 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1812 ipsendredirects && !srcrt && !next_hop) { 1813 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1814 u_long src = ntohl(ip->ip_src.s_addr); 1815 1816 if (RTA(rt) && 1817 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1818 if (rt->rt_flags & RTF_GATEWAY) 1819 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1820 else 1821 dest = pkt_dst.s_addr; 1822 /* Router requirements says to only send host redirects */ 1823 type = ICMP_REDIRECT; 1824 code = ICMP_REDIRECT_HOST; 1825 #ifdef DIAGNOSTIC 1826 if (ipprintfs) 1827 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1828 #endif 1829 } 1830 } 1831 1832 { 1833 struct m_hdr tag; 1834 1835 if (next_hop) { 1836 /* Pass IPFORWARD info if available */ 1837 1838 tag.mh_type = MT_TAG; 1839 tag.mh_flags = PACKET_TAG_IPFORWARD; 1840 tag.mh_data = (caddr_t)next_hop; 1841 tag.mh_next = m; 1842 m = (struct mbuf *)&tag; 1843 } 1844 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1845 IP_FORWARDING, 0, NULL); 1846 } 1847 if (error) 1848 ipstat.ips_cantforward++; 1849 else { 1850 ipstat.ips_forward++; 1851 if (type) 1852 ipstat.ips_redirectsent++; 1853 else { 1854 if (mcopy) { 1855 ipflow_create(&ipforward_rt, mcopy); 1856 m_freem(mcopy); 1857 } 1858 return; 1859 } 1860 } 1861 if (mcopy == NULL) 1862 return; 1863 destifp = NULL; 1864 1865 switch (error) { 1866 1867 case 0: /* forwarded, but need redirect */ 1868 /* type, code set above */ 1869 break; 1870 1871 case ENETUNREACH: /* shouldn't happen, checked above */ 1872 case EHOSTUNREACH: 1873 case ENETDOWN: 1874 case EHOSTDOWN: 1875 default: 1876 type = ICMP_UNREACH; 1877 code = ICMP_UNREACH_HOST; 1878 break; 1879 1880 case EMSGSIZE: 1881 type = ICMP_UNREACH; 1882 code = ICMP_UNREACH_NEEDFRAG; 1883 #ifdef IPSEC 1884 /* 1885 * If the packet is routed over IPsec tunnel, tell the 1886 * originator the tunnel MTU. 1887 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1888 * XXX quickhack!!! 1889 */ 1890 if (ipforward_rt.ro_rt) { 1891 struct secpolicy *sp = NULL; 1892 int ipsecerror; 1893 int ipsechdr; 1894 struct route *ro; 1895 1896 sp = ipsec4_getpolicybyaddr(mcopy, 1897 IPSEC_DIR_OUTBOUND, 1898 IP_FORWARDING, 1899 &ipsecerror); 1900 1901 if (sp == NULL) 1902 destifp = ipforward_rt.ro_rt->rt_ifp; 1903 else { 1904 /* count IPsec header size */ 1905 ipsechdr = ipsec4_hdrsiz(mcopy, 1906 IPSEC_DIR_OUTBOUND, 1907 NULL); 1908 1909 /* 1910 * find the correct route for outer IPv4 1911 * header, compute tunnel MTU. 1912 * 1913 * XXX BUG ALERT 1914 * The "dummyifp" code relies upon the fact 1915 * that icmp_error() touches only ifp->if_mtu. 1916 */ 1917 /*XXX*/ 1918 destifp = NULL; 1919 if (sp->req != NULL 1920 && sp->req->sav != NULL 1921 && sp->req->sav->sah != NULL) { 1922 ro = &sp->req->sav->sah->sa_route; 1923 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1924 dummyifp.if_mtu = 1925 ro->ro_rt->rt_ifp->if_mtu; 1926 dummyifp.if_mtu -= ipsechdr; 1927 destifp = &dummyifp; 1928 } 1929 } 1930 1931 key_freesp(sp); 1932 } 1933 } 1934 #elif FAST_IPSEC 1935 /* 1936 * If the packet is routed over IPsec tunnel, tell the 1937 * originator the tunnel MTU. 1938 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1939 * XXX quickhack!!! 1940 */ 1941 if (ipforward_rt.ro_rt) { 1942 struct secpolicy *sp = NULL; 1943 int ipsecerror; 1944 int ipsechdr; 1945 struct route *ro; 1946 1947 sp = ipsec_getpolicybyaddr(mcopy, 1948 IPSEC_DIR_OUTBOUND, 1949 IP_FORWARDING, 1950 &ipsecerror); 1951 1952 if (sp == NULL) 1953 destifp = ipforward_rt.ro_rt->rt_ifp; 1954 else { 1955 /* count IPsec header size */ 1956 ipsechdr = ipsec4_hdrsiz(mcopy, 1957 IPSEC_DIR_OUTBOUND, 1958 NULL); 1959 1960 /* 1961 * find the correct route for outer IPv4 1962 * header, compute tunnel MTU. 1963 * 1964 * XXX BUG ALERT 1965 * The "dummyifp" code relies upon the fact 1966 * that icmp_error() touches only ifp->if_mtu. 1967 */ 1968 /*XXX*/ 1969 destifp = NULL; 1970 if (sp->req != NULL 1971 && sp->req->sav != NULL 1972 && sp->req->sav->sah != NULL) { 1973 ro = &sp->req->sav->sah->sa_route; 1974 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1975 dummyifp.if_mtu = 1976 ro->ro_rt->rt_ifp->if_mtu; 1977 dummyifp.if_mtu -= ipsechdr; 1978 destifp = &dummyifp; 1979 } 1980 } 1981 1982 KEY_FREESP(&sp); 1983 } 1984 } 1985 #else /* !IPSEC && !FAST_IPSEC */ 1986 if (ipforward_rt.ro_rt) 1987 destifp = ipforward_rt.ro_rt->rt_ifp; 1988 #endif /*IPSEC*/ 1989 ipstat.ips_cantfrag++; 1990 break; 1991 1992 case ENOBUFS: 1993 /* 1994 * A router should not generate ICMP_SOURCEQUENCH as 1995 * required in RFC1812 Requirements for IP Version 4 Routers. 1996 * Source quench could be a big problem under DoS attacks, 1997 * or if the underlying interface is rate-limited. 1998 * Those who need source quench packets may re-enable them 1999 * via the net.inet.ip.sendsourcequench sysctl. 2000 */ 2001 if (ip_sendsourcequench == 0) { 2002 m_freem(mcopy); 2003 return; 2004 } else { 2005 type = ICMP_SOURCEQUENCH; 2006 code = 0; 2007 } 2008 break; 2009 2010 case EACCES: /* ipfw denied packet */ 2011 m_freem(mcopy); 2012 return; 2013 } 2014 icmp_error(mcopy, type, code, dest, destifp); 2015 } 2016 2017 void 2018 ip_savecontrol(inp, mp, ip, m) 2019 struct inpcb *inp; 2020 struct mbuf **mp; 2021 struct ip *ip; 2022 struct mbuf *m; 2023 { 2024 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2025 struct timeval tv; 2026 2027 microtime(&tv); 2028 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2029 SCM_TIMESTAMP, SOL_SOCKET); 2030 if (*mp) 2031 mp = &(*mp)->m_next; 2032 } 2033 if (inp->inp_flags & INP_RECVDSTADDR) { 2034 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2035 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2036 if (*mp) 2037 mp = &(*mp)->m_next; 2038 } 2039 #ifdef notyet 2040 /* XXX 2041 * Moving these out of udp_input() made them even more broken 2042 * than they already were. 2043 */ 2044 /* options were tossed already */ 2045 if (inp->inp_flags & INP_RECVOPTS) { 2046 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2047 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2048 if (*mp) 2049 mp = &(*mp)->m_next; 2050 } 2051 /* ip_srcroute doesn't do what we want here, need to fix */ 2052 if (inp->inp_flags & INP_RECVRETOPTS) { 2053 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2054 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2055 if (*mp) 2056 mp = &(*mp)->m_next; 2057 } 2058 #endif 2059 if (inp->inp_flags & INP_RECVIF) { 2060 struct ifnet *ifp; 2061 struct sdlbuf { 2062 struct sockaddr_dl sdl; 2063 u_char pad[32]; 2064 } sdlbuf; 2065 struct sockaddr_dl *sdp; 2066 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2067 2068 if (((ifp = m->m_pkthdr.rcvif)) 2069 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2070 sdp = (struct sockaddr_dl *)(ifnet_addrs 2071 [ifp->if_index - 1]->ifa_addr); 2072 /* 2073 * Change our mind and don't try copy. 2074 */ 2075 if ((sdp->sdl_family != AF_LINK) 2076 || (sdp->sdl_len > sizeof(sdlbuf))) { 2077 goto makedummy; 2078 } 2079 bcopy(sdp, sdl2, sdp->sdl_len); 2080 } else { 2081 makedummy: 2082 sdl2->sdl_len 2083 = offsetof(struct sockaddr_dl, sdl_data[0]); 2084 sdl2->sdl_family = AF_LINK; 2085 sdl2->sdl_index = 0; 2086 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2087 } 2088 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2089 IP_RECVIF, IPPROTO_IP); 2090 if (*mp) 2091 mp = &(*mp)->m_next; 2092 } 2093 } 2094 2095 /* 2096 * XXX these routines are called from the upper part of the kernel. 2097 * 2098 * They could also be moved to ip_mroute.c, since all the RSVP 2099 * handling is done there already. 2100 */ 2101 int 2102 ip_rsvp_init(struct socket *so) 2103 { 2104 if (so->so_type != SOCK_RAW || 2105 so->so_proto->pr_protocol != IPPROTO_RSVP) 2106 return EOPNOTSUPP; 2107 2108 if (ip_rsvpd != NULL) 2109 return EADDRINUSE; 2110 2111 ip_rsvpd = so; 2112 /* 2113 * This may seem silly, but we need to be sure we don't over-increment 2114 * the RSVP counter, in case something slips up. 2115 */ 2116 if (!ip_rsvp_on) { 2117 ip_rsvp_on = 1; 2118 rsvp_on++; 2119 } 2120 2121 return 0; 2122 } 2123 2124 int 2125 ip_rsvp_done(void) 2126 { 2127 ip_rsvpd = NULL; 2128 /* 2129 * This may seem silly, but we need to be sure we don't over-decrement 2130 * the RSVP counter, in case something slips up. 2131 */ 2132 if (ip_rsvp_on) { 2133 ip_rsvp_on = 0; 2134 rsvp_on--; 2135 } 2136 return 0; 2137 } 2138 2139 void 2140 rsvp_input(struct mbuf *m, int off, int proto) /* XXX must fixup manually */ 2141 { 2142 if (rsvp_input_p) { /* call the real one if loaded */ 2143 rsvp_input_p(m, off, proto); 2144 return; 2145 } 2146 2147 /* Can still get packets with rsvp_on = 0 if there is a local member 2148 * of the group to which the RSVP packet is addressed. But in this 2149 * case we want to throw the packet away. 2150 */ 2151 2152 if (!rsvp_on) { 2153 m_freem(m); 2154 return; 2155 } 2156 2157 if (ip_rsvpd != NULL) { 2158 rip_input(m, off, proto); 2159 return; 2160 } 2161 /* Drop the packet */ 2162 m_freem(m); 2163 } 2164 2165