Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netinet/ip_input.c
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1 /* 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 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 * $FreeBSD$ 35 */ 36 37 #define _IP_VHL 38 39 #include "opt_bootp.h" 40 #include "opt_ipfw.h" 41 #include "opt_ipdn.h" 42 #include "opt_ipdivert.h" 43 #include "opt_ipfilter.h" 44 #include "opt_ipstealth.h" 45 #include "opt_ipsec.h" 46 #include "opt_random_ip_id.h" 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/callout.h> 51 #include <sys/eventhandler.h> 52 #include <sys/mbuf.h> 53 #include <sys/malloc.h> 54 #include <sys/domain.h> 55 #include <sys/protosw.h> 56 #include <sys/socket.h> 57 #include <sys/time.h> 58 #include <sys/kernel.h> 59 #include <sys/syslog.h> 60 #include <sys/sysctl.h> 61 62 #include <net/if.h> 63 #include <net/if_types.h> 64 #include <net/if_var.h> 65 #include <net/if_dl.h> 66 #include <net/route.h> 67 #include <net/netisr.h> 68 #include <net/intrq.h> 69 70 #include <netinet/in.h> 71 #include <netinet/in_systm.h> 72 #include <netinet/in_var.h> 73 #include <netinet/ip.h> 74 #include <netinet/in_pcb.h> 75 #include <netinet/ip_var.h> 76 #include <netinet/ip_icmp.h> 77 #include <machine/in_cksum.h> 78 79 #include <netinet/ipprotosw.h> 80 81 #include <sys/socketvar.h> 82 83 #include <netinet/ip_fw.h> 84 #include <netinet/ip_dummynet.h> 85 86 #ifdef IPSEC 87 #include <netinet6/ipsec.h> 88 #include <netkey/key.h> 89 #endif 90 91 #ifdef FAST_IPSEC 92 #include <netipsec/ipsec.h> 93 #include <netipsec/key.h> 94 #endif 95 96 int rsvp_on = 0; 97 static int ip_rsvp_on; 98 struct socket *ip_rsvpd; 99 100 int ipforwarding = 0; 101 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 102 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 103 104 static int ipsendredirects = 1; /* XXX */ 105 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 106 &ipsendredirects, 0, "Enable sending IP redirects"); 107 108 int ip_defttl = IPDEFTTL; 109 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 110 &ip_defttl, 0, "Maximum TTL on IP packets"); 111 112 static int ip_dosourceroute = 0; 113 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 114 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 115 116 static int ip_acceptsourceroute = 0; 117 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 118 CTLFLAG_RW, &ip_acceptsourceroute, 0, 119 "Enable accepting source routed IP packets"); 120 121 static int ip_keepfaith = 0; 122 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 123 &ip_keepfaith, 0, 124 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 125 126 static int nipq = 0; /* total # of reass queues */ 127 static int maxnipq; 128 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 129 &maxnipq, 0, 130 "Maximum number of IPv4 fragment reassembly queue entries"); 131 132 static int maxfragsperpacket; 133 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 134 &maxfragsperpacket, 0, 135 "Maximum number of IPv4 fragments allowed per packet"); 136 137 static int ip_sendsourcequench = 0; 138 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 139 &ip_sendsourcequench, 0, 140 "Enable the transmission of source quench packets"); 141 142 /* 143 * XXX - Setting ip_checkinterface mostly implements the receive side of 144 * the Strong ES model described in RFC 1122, but since the routing table 145 * and transmit implementation do not implement the Strong ES model, 146 * setting this to 1 results in an odd hybrid. 147 * 148 * XXX - ip_checkinterface currently must be disabled if you use ipnat 149 * to translate the destination address to another local interface. 150 * 151 * XXX - ip_checkinterface must be disabled if you add IP aliases 152 * to the loopback interface instead of the interface where the 153 * packets for those addresses are received. 154 */ 155 static int ip_checkinterface = 0; 156 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 157 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 158 159 #ifdef DIAGNOSTIC 160 static int ipprintfs = 0; 161 #endif 162 163 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 struct callout ipport_tick_callout; 189 const int ipintrq_present = 1; 190 191 #ifdef IPCTL_DEFMTU 192 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 193 &ip_mtu, 0, "Default MTU"); 194 #endif 195 196 #ifdef IPSTEALTH 197 static int ipstealth = 0; 198 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 199 &ipstealth, 0, ""); 200 #endif 201 202 203 /* Firewall hooks */ 204 ip_fw_chk_t *ip_fw_chk_ptr; 205 int fw_enable = 1 ; 206 int fw_one_pass = 1; 207 208 /* Dummynet hooks */ 209 ip_dn_io_t *ip_dn_io_ptr; 210 211 int (*fr_checkp) __P((struct ip *, int, struct ifnet *, int, struct mbuf **)) = NULL; 212 213 /* 214 * XXX this is ugly -- the following two global variables are 215 * used to store packet state while it travels through the stack. 216 * Note that the code even makes assumptions on the size and 217 * alignment of fields inside struct ip_srcrt so e.g. adding some 218 * fields will break the code. This needs to be fixed. 219 * 220 * We need to save the IP options in case a protocol wants to respond 221 * to an incoming packet over the same route if the packet got here 222 * using IP source routing. This allows connection establishment and 223 * maintenance when the remote end is on a network that is not known 224 * to us. 225 */ 226 static int ip_nhops = 0; 227 static struct ip_srcrt { 228 struct in_addr dst; /* final destination */ 229 char nop; /* one NOP to align */ 230 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 231 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 232 } ip_srcrt; 233 234 static void save_rte(u_char *, struct in_addr); 235 static int ip_dooptions(struct mbuf *m, int, 236 struct sockaddr_in *next_hop); 237 static void ip_forward(struct mbuf *m, int srcrt, 238 struct sockaddr_in *next_hop); 239 static void ip_freef(struct ipq *); 240 static struct mbuf *ip_reass(struct mbuf *, struct ipq *, 241 struct ipq *, u_int32_t *, u_int16_t *); 242 static void ipintr(void); 243 244 /* 245 * IP initialization: fill in IP protocol switch table. 246 * All protocols not implemented in kernel go to raw IP protocol handler. 247 */ 248 void 249 ip_init() 250 { 251 register struct ipprotosw *pr; 252 register int i; 253 254 TAILQ_INIT(&in_ifaddrhead); 255 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 256 pr = (struct ipprotosw *)pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 257 if (pr == 0) 258 panic("ip_init"); 259 for (i = 0; i < IPPROTO_MAX; i++) 260 ip_protox[i] = pr - inetsw; 261 for (pr = (struct ipprotosw *)inetdomain.dom_protosw; 262 pr < (struct ipprotosw *)inetdomain.dom_protoswNPROTOSW; pr++) 263 if (pr->pr_domain->dom_family == PF_INET && 264 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 265 ip_protox[pr->pr_protocol] = pr - inetsw; 266 267 for (i = 0; i < IPREASS_NHASH; i++) 268 ipq[i].next = ipq[i].prev = &ipq[i]; 269 270 maxnipq = nmbclusters / 32; 271 maxfragsperpacket = 16; 272 273 /* Start ipport_tick. */ 274 callout_init(&ipport_tick_callout); 275 ipport_tick(NULL); 276 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL, 277 SHUTDOWN_PRI_DEFAULT); 278 279 #ifndef RANDOM_IP_ID 280 ip_id = time_second & 0xffff; 281 #endif 282 ipintrq.ifq_maxlen = ipqmaxlen; 283 284 register_netisr(NETISR_IP, ipintr); 285 } 286 287 void ip_fini(xtp) 288 void *xtp; 289 { 290 callout_stop(&ipport_tick_callout); 291 } 292 293 294 /* 295 * XXX watch out this one. It is perhaps used as a cache for 296 * the most recently used route ? it is cleared in in_addroute() 297 * when a new route is successfully created. 298 */ 299 struct route ipforward_rt; 300 static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 301 302 /* 303 * Ip input routine. Checksum and byte swap header. If fragmented 304 * try to reassemble. Process options. Pass to next level. 305 */ 306 void 307 ip_input(struct mbuf *m) 308 { 309 struct ip *ip; 310 struct ipq *fp; 311 struct in_ifaddr *ia = NULL; 312 struct ifaddr *ifa; 313 int i, hlen, checkif; 314 u_short sum; 315 struct in_addr pkt_dst; 316 u_int32_t divert_info = 0; /* packet divert/tee info */ 317 struct ip_fw_args args; 318 #ifdef FAST_IPSEC 319 struct m_tag *mtag; 320 struct tdb_ident *tdbi; 321 struct secpolicy *sp; 322 int s, error; 323 #endif /* FAST_IPSEC */ 324 325 args.eh = NULL; 326 args.oif = NULL; 327 args.rule = NULL; 328 args.divert_rule = 0; /* divert cookie */ 329 args.next_hop = NULL; 330 331 /* Grab info from MT_TAG mbufs prepended to the chain. */ 332 for (; m && m->m_type == MT_TAG; m = m->m_next) { 333 switch(m->_m_tag_id) { 334 default: 335 printf("ip_input: unrecognised MT_TAG tag %d\n", 336 m->_m_tag_id); 337 break; 338 339 case PACKET_TAG_DUMMYNET: 340 args.rule = ((struct dn_pkt *)m)->rule; 341 break; 342 343 case PACKET_TAG_DIVERT: 344 args.divert_rule = (int)m->m_hdr.mh_data & 0xffff; 345 break; 346 347 case PACKET_TAG_IPFORWARD: 348 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 349 break; 350 } 351 } 352 353 KASSERT(m != NULL && (m->m_flags & M_PKTHDR) != 0, 354 ("ip_input: no HDR")); 355 356 if (args.rule) { /* dummynet already filtered us */ 357 ip = mtod(m, struct ip *); 358 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 359 goto iphack ; 360 } 361 362 ipstat.ips_total++; 363 364 if (m->m_pkthdr.len < sizeof(struct ip)) 365 goto tooshort; 366 367 if (m->m_len < sizeof (struct ip) && 368 (m = m_pullup(m, sizeof (struct ip))) == 0) { 369 ipstat.ips_toosmall++; 370 return; 371 } 372 ip = mtod(m, struct ip *); 373 374 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 375 ipstat.ips_badvers++; 376 goto bad; 377 } 378 379 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 380 if (hlen < sizeof(struct ip)) { /* minimum header length */ 381 ipstat.ips_badhlen++; 382 goto bad; 383 } 384 if (hlen > m->m_len) { 385 if ((m = m_pullup(m, hlen)) == 0) { 386 ipstat.ips_badhlen++; 387 return; 388 } 389 ip = mtod(m, struct ip *); 390 } 391 392 /* 127/8 must not appear on wire - RFC1122 */ 393 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 394 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 395 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 396 ipstat.ips_badaddr++; 397 goto bad; 398 } 399 } 400 401 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 402 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 403 } else { 404 if (hlen == sizeof(struct ip)) { 405 sum = in_cksum_hdr(ip); 406 } else { 407 sum = in_cksum(m, hlen); 408 } 409 } 410 if (sum) { 411 ipstat.ips_badsum++; 412 goto bad; 413 } 414 415 /* 416 * Convert fields to host representation. 417 */ 418 ip->ip_len = ntohs(ip->ip_len); 419 if (ip->ip_len < hlen) { 420 ipstat.ips_badlen++; 421 goto bad; 422 } 423 ip->ip_off = ntohs(ip->ip_off); 424 425 /* 426 * Check that the amount of data in the buffers 427 * is as at least much as the IP header would have us expect. 428 * Trim mbufs if longer than we expect. 429 * Drop packet if shorter than we expect. 430 */ 431 if (m->m_pkthdr.len < ip->ip_len) { 432 tooshort: 433 ipstat.ips_tooshort++; 434 goto bad; 435 } 436 if (m->m_pkthdr.len > ip->ip_len) { 437 if (m->m_len == m->m_pkthdr.len) { 438 m->m_len = ip->ip_len; 439 m->m_pkthdr.len = ip->ip_len; 440 } else 441 m_adj(m, ip->ip_len - m->m_pkthdr.len); 442 } 443 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 444 /* 445 * Bypass packet filtering for packets from a tunnel (gif). 446 */ 447 if (ipsec_gethist(m, NULL)) 448 goto pass; 449 #endif 450 #if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF) 451 /* 452 * Bypass packet filtering for packets from a tunnel (gif). 453 */ 454 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 455 goto pass; 456 #endif 457 458 /* 459 * IpHack's section. 460 * Right now when no processing on packet has done 461 * and it is still fresh out of network we do our black 462 * deals with it. 463 * - Firewall: deny/allow/divert 464 * - Xlate: translate packet's addr/port (NAT). 465 * - Pipe: pass pkt through dummynet. 466 * - Wrap: fake packet's addr/port <unimpl.> 467 * - Encapsulate: put it in another IP and send out. <unimp.> 468 */ 469 470 iphack: 471 /* 472 * Check if we want to allow this packet to be processed. 473 * Consider it to be bad if not. 474 */ 475 if (fr_checkp) { 476 struct mbuf *m1 = m; 477 478 if ((*fr_checkp)(ip, hlen, m->m_pkthdr.rcvif, 0, &m1) || !m1) 479 return; 480 ip = mtod(m = m1, struct ip *); 481 } 482 if (fw_enable && IPFW_LOADED) { 483 /* 484 * If we've been forwarded from the output side, then 485 * skip the firewall a second time 486 */ 487 if (args.next_hop) 488 goto ours; 489 490 args.m = m; 491 i = ip_fw_chk_ptr(&args); 492 m = args.m; 493 494 if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 495 if (m) 496 m_freem(m); 497 return; 498 } 499 ip = mtod(m, struct ip *); /* just in case m changed */ 500 if (i == 0 && args.next_hop == NULL) /* common case */ 501 goto pass; 502 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) { 503 /* Send packet to the appropriate pipe */ 504 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 505 return; 506 } 507 #ifdef IPDIVERT 508 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 509 /* Divert or tee packet */ 510 divert_info = i; 511 goto ours; 512 } 513 #endif 514 if (i == 0 && args.next_hop != NULL) 515 goto pass; 516 /* 517 * if we get here, the packet must be dropped 518 */ 519 m_freem(m); 520 return; 521 } 522 pass: 523 524 /* 525 * Process options and, if not destined for us, 526 * ship it on. ip_dooptions returns 1 when an 527 * error was detected (causing an icmp message 528 * to be sent and the original packet to be freed). 529 */ 530 ip_nhops = 0; /* for source routed packets */ 531 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, args.next_hop)) 532 return; 533 534 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 535 * matter if it is destined to another node, or whether it is 536 * a multicast one, RSVP wants it! and prevents it from being forwarded 537 * anywhere else. Also checks if the rsvp daemon is running before 538 * grabbing the packet. 539 */ 540 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 541 goto ours; 542 543 /* 544 * Check our list of addresses, to see if the packet is for us. 545 * If we don't have any addresses, assume any unicast packet 546 * we receive might be for us (and let the upper layers deal 547 * with it). 548 */ 549 if (TAILQ_EMPTY(&in_ifaddrhead) && 550 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 551 goto ours; 552 553 /* 554 * Cache the destination address of the packet; this may be 555 * changed by use of 'ipfw fwd'. 556 */ 557 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 558 559 /* 560 * Enable a consistency check between the destination address 561 * and the arrival interface for a unicast packet (the RFC 1122 562 * strong ES model) if IP forwarding is disabled and the packet 563 * is not locally generated and the packet is not subject to 564 * 'ipfw fwd'. 565 * 566 * XXX - Checking also should be disabled if the destination 567 * address is ipnat'ed to a different interface. 568 * 569 * XXX - Checking is incompatible with IP aliases added 570 * to the loopback interface instead of the interface where 571 * the packets are received. 572 */ 573 checkif = ip_checkinterface && (ipforwarding == 0) && 574 m->m_pkthdr.rcvif != NULL && 575 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 576 (args.next_hop == NULL); 577 578 /* 579 * Check for exact addresses in the hash bucket. 580 */ 581 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 582 /* 583 * If the address matches, verify that the packet 584 * arrived via the correct interface if checking is 585 * enabled. 586 */ 587 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 588 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 589 goto ours; 590 } 591 /* 592 * Check for broadcast addresses. 593 * 594 * Only accept broadcast packets that arrive via the matching 595 * interface. Reception of forwarded directed broadcasts would 596 * be handled via ip_forward() and ether_output() with the loopback 597 * into the stack for SIMPLEX interfaces handled by ether_output(). 598 */ 599 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 600 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 601 if (ifa->ifa_addr->sa_family != AF_INET) 602 continue; 603 ia = ifatoia(ifa); 604 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 605 pkt_dst.s_addr) 606 goto ours; 607 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 608 goto ours; 609 #ifdef BOOTP_COMPAT 610 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 611 goto ours; 612 #endif 613 } 614 } 615 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 616 struct in_multi *inm; 617 if (ip_mrouter) { 618 /* 619 * If we are acting as a multicast router, all 620 * incoming multicast packets are passed to the 621 * kernel-level multicast forwarding function. 622 * The packet is returned (relatively) intact; if 623 * ip_mforward() returns a non-zero value, the packet 624 * must be discarded, else it may be accepted below. 625 */ 626 if (ip_mforward && 627 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 628 ipstat.ips_cantforward++; 629 m_freem(m); 630 return; 631 } 632 633 /* 634 * The process-level routing daemon needs to receive 635 * all multicast IGMP packets, whether or not this 636 * host belongs to their destination groups. 637 */ 638 if (ip->ip_p == IPPROTO_IGMP) 639 goto ours; 640 ipstat.ips_forward++; 641 } 642 /* 643 * See if we belong to the destination multicast group on the 644 * arrival interface. 645 */ 646 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 647 if (inm == NULL) { 648 ipstat.ips_notmember++; 649 m_freem(m); 650 return; 651 } 652 goto ours; 653 } 654 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 655 goto ours; 656 if (ip->ip_dst.s_addr == INADDR_ANY) 657 goto ours; 658 659 /* 660 * FAITH(Firewall Aided Internet Translator) 661 */ 662 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 663 if (ip_keepfaith) { 664 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 665 goto ours; 666 } 667 m_freem(m); 668 return; 669 } 670 671 /* 672 * Not for us; forward if possible and desirable. 673 */ 674 if (ipforwarding == 0) { 675 ipstat.ips_cantforward++; 676 m_freem(m); 677 } else { 678 #ifdef IPSEC 679 /* 680 * Enforce inbound IPsec SPD. 681 */ 682 if (ipsec4_in_reject(m, NULL)) { 683 ipsecstat.in_polvio++; 684 goto bad; 685 } 686 #endif /* IPSEC */ 687 #ifdef FAST_IPSEC 688 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 689 s = splnet(); 690 if (mtag != NULL) { 691 tdbi = (struct tdb_ident *)(mtag + 1); 692 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 693 } else { 694 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 695 IP_FORWARDING, &error); 696 } 697 if (sp == NULL) { /* NB: can happen if error */ 698 splx(s); 699 /*XXX error stat???*/ 700 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 701 goto bad; 702 } 703 704 /* 705 * Check security policy against packet attributes. 706 */ 707 error = ipsec_in_reject(sp, m); 708 KEY_FREESP(&sp); 709 splx(s); 710 if (error) { 711 ipstat.ips_cantforward++; 712 goto bad; 713 } 714 #endif /* FAST_IPSEC */ 715 ip_forward(m, 0, args.next_hop); 716 } 717 return; 718 719 ours: 720 #ifdef IPSTEALTH 721 /* 722 * IPSTEALTH: Process non-routing options only 723 * if the packet is destined for us. 724 */ 725 if (ipstealth && hlen > sizeof (struct ip) && 726 ip_dooptions(m, 1, args.next_hop)) 727 return; 728 #endif /* IPSTEALTH */ 729 730 /* Count the packet in the ip address stats */ 731 if (ia != NULL) { 732 ia->ia_ifa.if_ipackets++; 733 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 734 } 735 736 /* 737 * If offset or IP_MF are set, must reassemble. 738 * Otherwise, nothing need be done. 739 * (We could look in the reassembly queue to see 740 * if the packet was previously fragmented, 741 * but it's not worth the time; just let them time out.) 742 */ 743 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 744 745 /* If maxnipq is 0, never accept fragments. */ 746 if (maxnipq == 0) { 747 ipstat.ips_fragments++; 748 ipstat.ips_fragdropped++; 749 goto bad; 750 } 751 752 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 753 /* 754 * Look for queue of fragments 755 * of this datagram. 756 */ 757 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 758 if (ip->ip_id == fp->ipq_id && 759 ip->ip_src.s_addr == fp->ipq_src.s_addr && 760 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 761 ip->ip_p == fp->ipq_p) 762 goto found; 763 764 fp = 0; 765 766 /* 767 * Enforce upper bound on number of fragmented packets 768 * for which we attempt reassembly; 769 * If maxnipq is -1, accept all fragments without limitation. 770 */ 771 if ((nipq > maxnipq) && (maxnipq > 0)) { 772 /* 773 * drop something from the tail of the current queue 774 * before proceeding further 775 */ 776 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 777 for (i = 0; i < IPREASS_NHASH; i++) { 778 if (ipq[i].prev != &ipq[i]) { 779 ipstat.ips_fragtimeout += 780 ipq[i].prev->ipq_nfrags; 781 ip_freef(ipq[i].prev); 782 break; 783 } 784 } 785 } else { 786 ipstat.ips_fragtimeout += ipq[sum].prev->ipq_nfrags; 787 ip_freef(ipq[sum].prev); 788 } 789 } 790 found: 791 /* 792 * Adjust ip_len to not reflect header, 793 * convert offset of this to bytes. 794 */ 795 ip->ip_len -= hlen; 796 if (ip->ip_off & IP_MF) { 797 /* 798 * Make sure that fragments have a data length 799 * that's a non-zero multiple of 8 bytes. 800 */ 801 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 802 ipstat.ips_toosmall++; /* XXX */ 803 goto bad; 804 } 805 m->m_flags |= M_FRAG; 806 } else 807 m->m_flags &= ~M_FRAG; 808 ip->ip_off <<= 3; 809 810 /* 811 * Attempt reassembly; if it succeeds, proceed. 812 * ip_reass() will return a different mbuf, and update 813 * the divert info in divert_info and args.divert_rule. 814 */ 815 ipstat.ips_fragments++; 816 m->m_pkthdr.header = ip; 817 m = ip_reass(m, 818 fp, &ipq[sum], &divert_info, &args.divert_rule); 819 if (m == 0) 820 return; 821 ipstat.ips_reassembled++; 822 ip = mtod(m, struct ip *); 823 /* Get the header length of the reassembled packet */ 824 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 825 #ifdef IPDIVERT 826 /* Restore original checksum before diverting packet */ 827 if (divert_info != 0) { 828 ip->ip_len += hlen; 829 ip->ip_len = htons(ip->ip_len); 830 ip->ip_off = htons(ip->ip_off); 831 ip->ip_sum = 0; 832 if (hlen == sizeof(struct ip)) 833 ip->ip_sum = in_cksum_hdr(ip); 834 else 835 ip->ip_sum = in_cksum(m, hlen); 836 ip->ip_off = ntohs(ip->ip_off); 837 ip->ip_len = ntohs(ip->ip_len); 838 ip->ip_len -= hlen; 839 } 840 #endif 841 } else 842 ip->ip_len -= hlen; 843 844 #ifdef IPDIVERT 845 /* 846 * Divert or tee packet to the divert protocol if required. 847 */ 848 if (divert_info != 0) { 849 struct mbuf *clone = NULL; 850 851 /* Clone packet if we're doing a 'tee' */ 852 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 853 clone = m_dup(m, M_DONTWAIT); 854 855 /* Restore packet header fields to original values */ 856 ip->ip_len += hlen; 857 ip->ip_len = htons(ip->ip_len); 858 ip->ip_off = htons(ip->ip_off); 859 860 /* Deliver packet to divert input routine */ 861 divert_packet(m, 1, divert_info & 0xffff, args.divert_rule); 862 ipstat.ips_delivered++; 863 864 /* If 'tee', continue with original packet */ 865 if (clone == NULL) 866 return; 867 m = clone; 868 ip = mtod(m, struct ip *); 869 ip->ip_len += hlen; 870 /* 871 * Jump backwards to complete processing of the 872 * packet. But first clear divert_info to avoid 873 * entering this block again. 874 * We do not need to clear args.divert_rule 875 * or args.next_hop as they will not be used. 876 */ 877 divert_info = 0; 878 goto pass; 879 } 880 #endif 881 882 #ifdef 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 ipsec4_in_reject(m, NULL)) { 890 ipsecstat.in_polvio++; 891 goto bad; 892 } 893 #endif 894 #if FAST_IPSEC 895 /* 896 * enforce IPsec policy checking if we are seeing last header. 897 * note that we do not visit this with protocols with pcb layer 898 * code - like udp/tcp/raw ip. 899 */ 900 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 901 /* 902 * Check if the packet has already had IPsec processing 903 * done. If so, then just pass it along. This tag gets 904 * set during AH, ESP, etc. input handling, before the 905 * packet is returned to the ip input queue for delivery. 906 */ 907 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 908 s = splnet(); 909 if (mtag != NULL) { 910 tdbi = (struct tdb_ident *)(mtag + 1); 911 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 912 } else { 913 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 914 IP_FORWARDING, &error); 915 } 916 if (sp != NULL) { 917 /* 918 * Check security policy against packet attributes. 919 */ 920 error = ipsec_in_reject(sp, m); 921 KEY_FREESP(&sp); 922 } else { 923 /* XXX error stat??? */ 924 error = EINVAL; 925 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 926 goto bad; 927 } 928 splx(s); 929 if (error) 930 goto bad; 931 } 932 #endif /* FAST_IPSEC */ 933 934 /* 935 * Switch out to protocol's input routine. 936 */ 937 ipstat.ips_delivered++; 938 if (args.next_hop && ip->ip_p == IPPROTO_TCP) { 939 /* TCP needs IPFORWARD info if available */ 940 struct m_hdr tag; 941 942 tag.mh_type = MT_TAG; 943 tag.mh_flags = PACKET_TAG_IPFORWARD; 944 tag.mh_data = (caddr_t)args.next_hop; 945 tag.mh_next = m; 946 947 (*inetsw[ip_protox[ip->ip_p]].pr_input)( 948 (struct mbuf *)&tag, hlen, ip->ip_p); 949 } else 950 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, ip->ip_p); 951 return; 952 bad: 953 m_freem(m); 954 } 955 956 /* 957 * IP software interrupt routine - to go away sometime soon 958 */ 959 static void 960 ipintr(void) 961 { 962 int s; 963 struct mbuf *m; 964 965 while(1) { 966 s = splimp(); 967 IF_DEQUEUE(&ipintrq, m); 968 splx(s); 969 if (m == 0) 970 return; 971 ip_input(m); 972 } 973 } 974 975 /* 976 * Take incoming datagram fragment and try to reassemble it into 977 * whole datagram. If a chain for reassembly of this datagram already 978 * exists, then it is given as fp; otherwise have to make a chain. 979 * 980 * When IPDIVERT enabled, keep additional state with each packet that 981 * tells us if we need to divert or tee the packet we're building. 982 * In particular, *divinfo includes the port and TEE flag, 983 * *divert_rule is the number of the matching rule. 984 */ 985 986 static struct mbuf * 987 ip_reass(struct mbuf *m, struct ipq *fp, struct ipq *where, 988 u_int32_t *divinfo, u_int16_t *divert_rule) 989 { 990 struct ip *ip = mtod(m, struct ip *); 991 register struct mbuf *p = 0, *q, *nq; 992 struct mbuf *t; 993 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 994 int i, next; 995 996 /* 997 * Presence of header sizes in mbufs 998 * would confuse code below. 999 */ 1000 m->m_data += hlen; 1001 m->m_len -= hlen; 1002 1003 /* 1004 * If first fragment to arrive, create a reassembly queue. 1005 */ 1006 if (fp == 0) { 1007 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 1008 goto dropfrag; 1009 fp = mtod(t, struct ipq *); 1010 insque(fp, where); 1011 nipq++; 1012 fp->ipq_nfrags = 1; 1013 fp->ipq_ttl = IPFRAGTTL; 1014 fp->ipq_p = ip->ip_p; 1015 fp->ipq_id = ip->ip_id; 1016 fp->ipq_src = ip->ip_src; 1017 fp->ipq_dst = ip->ip_dst; 1018 fp->ipq_frags = m; 1019 m->m_nextpkt = NULL; 1020 #ifdef IPDIVERT 1021 fp->ipq_div_info = 0; 1022 fp->ipq_div_cookie = 0; 1023 #endif 1024 goto inserted; 1025 } else { 1026 fp->ipq_nfrags++; 1027 } 1028 1029 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1030 1031 /* 1032 * Find a segment which begins after this one does. 1033 */ 1034 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1035 if (GETIP(q)->ip_off > ip->ip_off) 1036 break; 1037 1038 /* 1039 * If there is a preceding segment, it may provide some of 1040 * our data already. If so, drop the data from the incoming 1041 * segment. If it provides all of our data, drop us, otherwise 1042 * stick new segment in the proper place. 1043 * 1044 * If some of the data is dropped from the the preceding 1045 * segment, then it's checksum is invalidated. 1046 */ 1047 if (p) { 1048 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1049 if (i > 0) { 1050 if (i >= ip->ip_len) 1051 goto dropfrag; 1052 m_adj(m, i); 1053 m->m_pkthdr.csum_flags = 0; 1054 ip->ip_off += i; 1055 ip->ip_len -= i; 1056 } 1057 m->m_nextpkt = p->m_nextpkt; 1058 p->m_nextpkt = m; 1059 } else { 1060 m->m_nextpkt = fp->ipq_frags; 1061 fp->ipq_frags = m; 1062 } 1063 1064 /* 1065 * While we overlap succeeding segments trim them or, 1066 * if they are completely covered, dequeue them. 1067 */ 1068 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1069 q = nq) { 1070 i = (ip->ip_off + ip->ip_len) - 1071 GETIP(q)->ip_off; 1072 if (i < GETIP(q)->ip_len) { 1073 GETIP(q)->ip_len -= i; 1074 GETIP(q)->ip_off += i; 1075 m_adj(q, i); 1076 q->m_pkthdr.csum_flags = 0; 1077 break; 1078 } 1079 nq = q->m_nextpkt; 1080 m->m_nextpkt = nq; 1081 ipstat.ips_fragdropped++; 1082 fp->ipq_nfrags--; 1083 m_freem(q); 1084 } 1085 1086 inserted: 1087 1088 #ifdef IPDIVERT 1089 /* 1090 * Transfer firewall instructions to the fragment structure. 1091 * Only trust info in the fragment at offset 0. 1092 */ 1093 if (ip->ip_off == 0) { 1094 fp->ipq_div_info = *divinfo; 1095 fp->ipq_div_cookie = *divert_rule; 1096 } 1097 *divinfo = 0; 1098 *divert_rule = 0; 1099 #endif 1100 1101 /* 1102 * Check for complete reassembly and perform frag per packet 1103 * limiting. 1104 * 1105 * Frag limiting is performed here so that the nth frag has 1106 * a chance to complete the packet before we drop the packet. 1107 * As a result, n+1 frags are actually allowed per packet, but 1108 * only n will ever be stored. (n = maxfragsperpacket.) 1109 * 1110 */ 1111 next = 0; 1112 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1113 if (GETIP(q)->ip_off != next) { 1114 if (fp->ipq_nfrags > maxfragsperpacket) { 1115 ipstat.ips_fragdropped += fp->ipq_nfrags; 1116 ip_freef(fp); 1117 } 1118 return (0); 1119 } 1120 next += GETIP(q)->ip_len; 1121 } 1122 /* Make sure the last packet didn't have the IP_MF flag */ 1123 if (p->m_flags & M_FRAG) { 1124 if (fp->ipq_nfrags > maxfragsperpacket) { 1125 ipstat.ips_fragdropped += fp->ipq_nfrags; 1126 ip_freef(fp); 1127 } 1128 return (0); 1129 } 1130 1131 /* 1132 * Reassembly is complete. Make sure the packet is a sane size. 1133 */ 1134 q = fp->ipq_frags; 1135 ip = GETIP(q); 1136 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1137 ipstat.ips_toolong++; 1138 ipstat.ips_fragdropped += fp->ipq_nfrags; 1139 ip_freef(fp); 1140 return (0); 1141 } 1142 1143 /* 1144 * Concatenate fragments. 1145 */ 1146 m = q; 1147 t = m->m_next; 1148 m->m_next = 0; 1149 m_cat(m, t); 1150 nq = q->m_nextpkt; 1151 q->m_nextpkt = 0; 1152 for (q = nq; q != NULL; q = nq) { 1153 nq = q->m_nextpkt; 1154 q->m_nextpkt = NULL; 1155 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1156 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1157 m_cat(m, q); 1158 } 1159 1160 #ifdef IPDIVERT 1161 /* 1162 * Extract firewall instructions from the fragment structure. 1163 */ 1164 *divinfo = fp->ipq_div_info; 1165 *divert_rule = fp->ipq_div_cookie; 1166 #endif 1167 1168 /* 1169 * Create header for new ip packet by 1170 * modifying header of first packet; 1171 * dequeue and discard fragment reassembly header. 1172 * Make header visible. 1173 */ 1174 ip->ip_len = next; 1175 ip->ip_src = fp->ipq_src; 1176 ip->ip_dst = fp->ipq_dst; 1177 remque(fp); 1178 nipq--; 1179 (void) m_free(dtom(fp)); 1180 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1181 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1182 /* some debugging cruft by sklower, below, will go away soon */ 1183 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1184 register int plen = 0; 1185 for (t = m; t; t = t->m_next) 1186 plen += t->m_len; 1187 m->m_pkthdr.len = plen; 1188 } 1189 return (m); 1190 1191 dropfrag: 1192 #ifdef IPDIVERT 1193 *divinfo = 0; 1194 *divert_rule = 0; 1195 #endif 1196 ipstat.ips_fragdropped++; 1197 if (fp != 0) 1198 fp->ipq_nfrags--; 1199 m_freem(m); 1200 return (0); 1201 1202 #undef GETIP 1203 } 1204 1205 /* 1206 * Free a fragment reassembly header and all 1207 * associated datagrams. 1208 */ 1209 static void 1210 ip_freef(fp) 1211 struct ipq *fp; 1212 { 1213 register struct mbuf *q; 1214 1215 while (fp->ipq_frags) { 1216 q = fp->ipq_frags; 1217 fp->ipq_frags = q->m_nextpkt; 1218 m_freem(q); 1219 } 1220 remque(fp); 1221 (void) m_free(dtom(fp)); 1222 nipq--; 1223 } 1224 1225 /* 1226 * IP timer processing; 1227 * if a timer expires on a reassembly 1228 * queue, discard it. 1229 */ 1230 void 1231 ip_slowtimo() 1232 { 1233 register struct ipq *fp; 1234 int s = splnet(); 1235 int i; 1236 1237 for (i = 0; i < IPREASS_NHASH; i++) { 1238 fp = ipq[i].next; 1239 if (fp == 0) 1240 continue; 1241 while (fp != &ipq[i]) { 1242 --fp->ipq_ttl; 1243 fp = fp->next; 1244 if (fp->prev->ipq_ttl == 0) { 1245 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1246 ip_freef(fp->prev); 1247 } 1248 } 1249 } 1250 /* 1251 * If we are over the maximum number of fragments 1252 * (due to the limit being lowered), drain off 1253 * enough to get down to the new limit. 1254 */ 1255 if (maxnipq >= 0 && nipq > maxnipq) { 1256 for (i = 0; i < IPREASS_NHASH; i++) { 1257 while (nipq > maxnipq && 1258 (ipq[i].next != &ipq[i])) { 1259 ipstat.ips_fragdropped += 1260 ipq[i].next->ipq_nfrags; 1261 ip_freef(ipq[i].next); 1262 } 1263 } 1264 } 1265 ipflow_slowtimo(); 1266 splx(s); 1267 } 1268 1269 /* 1270 * Drain off all datagram fragments. 1271 */ 1272 void 1273 ip_drain() 1274 { 1275 int i; 1276 1277 for (i = 0; i < IPREASS_NHASH; i++) { 1278 while (ipq[i].next != &ipq[i]) { 1279 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1280 ip_freef(ipq[i].next); 1281 } 1282 } 1283 in_rtqdrain(); 1284 } 1285 1286 /* 1287 * Do option processing on a datagram, 1288 * possibly discarding it if bad options are encountered, 1289 * or forwarding it if source-routed. 1290 * The pass argument is used when operating in the IPSTEALTH 1291 * mode to tell what options to process: 1292 * [LS]SRR (pass 0) or the others (pass 1). 1293 * The reason for as many as two passes is that when doing IPSTEALTH, 1294 * non-routing options should be processed only if the packet is for us. 1295 * Returns 1 if packet has been forwarded/freed, 1296 * 0 if the packet should be processed further. 1297 */ 1298 static int 1299 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1300 { 1301 struct ip *ip = mtod(m, struct ip *); 1302 u_char *cp; 1303 struct in_ifaddr *ia; 1304 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1305 struct in_addr *sin, dst; 1306 n_time ntime; 1307 1308 dst = ip->ip_dst; 1309 cp = (u_char *)(ip + 1); 1310 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1311 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1312 opt = cp[IPOPT_OPTVAL]; 1313 if (opt == IPOPT_EOL) 1314 break; 1315 if (opt == IPOPT_NOP) 1316 optlen = 1; 1317 else { 1318 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1319 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1320 goto bad; 1321 } 1322 optlen = cp[IPOPT_OLEN]; 1323 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1324 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1325 goto bad; 1326 } 1327 } 1328 switch (opt) { 1329 1330 default: 1331 break; 1332 1333 /* 1334 * Source routing with record. 1335 * Find interface with current destination address. 1336 * If none on this machine then drop if strictly routed, 1337 * or do nothing if loosely routed. 1338 * Record interface address and bring up next address 1339 * component. If strictly routed make sure next 1340 * address is on directly accessible net. 1341 */ 1342 case IPOPT_LSRR: 1343 case IPOPT_SSRR: 1344 #ifdef IPSTEALTH 1345 if (ipstealth && pass > 0) 1346 break; 1347 #endif 1348 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1349 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1350 goto bad; 1351 } 1352 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1353 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1354 goto bad; 1355 } 1356 ipaddr.sin_addr = ip->ip_dst; 1357 ia = (struct in_ifaddr *) 1358 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1359 if (ia == 0) { 1360 if (opt == IPOPT_SSRR) { 1361 type = ICMP_UNREACH; 1362 code = ICMP_UNREACH_SRCFAIL; 1363 goto bad; 1364 } 1365 if (!ip_dosourceroute) 1366 goto nosourcerouting; 1367 /* 1368 * Loose routing, and not at next destination 1369 * yet; nothing to do except forward. 1370 */ 1371 break; 1372 } 1373 off--; /* 0 origin */ 1374 if (off > optlen - (int)sizeof(struct in_addr)) { 1375 /* 1376 * End of source route. Should be for us. 1377 */ 1378 if (!ip_acceptsourceroute) 1379 goto nosourcerouting; 1380 save_rte(cp, ip->ip_src); 1381 break; 1382 } 1383 #ifdef IPSTEALTH 1384 if (ipstealth) 1385 goto dropit; 1386 #endif 1387 if (!ip_dosourceroute) { 1388 if (ipforwarding) { 1389 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1390 /* 1391 * Acting as a router, so generate ICMP 1392 */ 1393 nosourcerouting: 1394 strcpy(buf, inet_ntoa(ip->ip_dst)); 1395 log(LOG_WARNING, 1396 "attempted source route from %s to %s\n", 1397 inet_ntoa(ip->ip_src), buf); 1398 type = ICMP_UNREACH; 1399 code = ICMP_UNREACH_SRCFAIL; 1400 goto bad; 1401 } else { 1402 /* 1403 * Not acting as a router, so silently drop. 1404 */ 1405 #ifdef IPSTEALTH 1406 dropit: 1407 #endif 1408 ipstat.ips_cantforward++; 1409 m_freem(m); 1410 return (1); 1411 } 1412 } 1413 1414 /* 1415 * locate outgoing interface 1416 */ 1417 (void)memcpy(&ipaddr.sin_addr, cp + off, 1418 sizeof(ipaddr.sin_addr)); 1419 1420 if (opt == IPOPT_SSRR) { 1421 #define INA struct in_ifaddr * 1422 #define SA struct sockaddr * 1423 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1424 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1425 } else 1426 ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt); 1427 if (ia == 0) { 1428 type = ICMP_UNREACH; 1429 code = ICMP_UNREACH_SRCFAIL; 1430 goto bad; 1431 } 1432 ip->ip_dst = ipaddr.sin_addr; 1433 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1434 sizeof(struct in_addr)); 1435 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1436 /* 1437 * Let ip_intr's mcast routing check handle mcast pkts 1438 */ 1439 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1440 break; 1441 1442 case IPOPT_RR: 1443 #ifdef IPSTEALTH 1444 if (ipstealth && pass == 0) 1445 break; 1446 #endif 1447 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1448 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1449 goto bad; 1450 } 1451 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1452 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1453 goto bad; 1454 } 1455 /* 1456 * If no space remains, ignore. 1457 */ 1458 off--; /* 0 origin */ 1459 if (off > optlen - (int)sizeof(struct in_addr)) 1460 break; 1461 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1462 sizeof(ipaddr.sin_addr)); 1463 /* 1464 * locate outgoing interface; if we're the destination, 1465 * use the incoming interface (should be same). 1466 */ 1467 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1468 (ia = ip_rtaddr(ipaddr.sin_addr, 1469 &ipforward_rt)) == 0) { 1470 type = ICMP_UNREACH; 1471 code = ICMP_UNREACH_HOST; 1472 goto bad; 1473 } 1474 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1475 sizeof(struct in_addr)); 1476 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1477 break; 1478 1479 case IPOPT_TS: 1480 #ifdef IPSTEALTH 1481 if (ipstealth && pass == 0) 1482 break; 1483 #endif 1484 code = cp - (u_char *)ip; 1485 if (optlen < 4 || optlen > 40) { 1486 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1487 goto bad; 1488 } 1489 if ((off = cp[IPOPT_OFFSET]) < 5) { 1490 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1491 goto bad; 1492 } 1493 if (off > optlen - (int)sizeof(int32_t)) { 1494 cp[IPOPT_OFFSET + 1] += (1 << 4); 1495 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1496 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1497 goto bad; 1498 } 1499 break; 1500 } 1501 off--; /* 0 origin */ 1502 sin = (struct in_addr *)(cp + off); 1503 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1504 1505 case IPOPT_TS_TSONLY: 1506 break; 1507 1508 case IPOPT_TS_TSANDADDR: 1509 if (off + sizeof(n_time) + 1510 sizeof(struct in_addr) > optlen) { 1511 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1512 goto bad; 1513 } 1514 ipaddr.sin_addr = dst; 1515 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1516 m->m_pkthdr.rcvif); 1517 if (ia == 0) 1518 continue; 1519 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1520 sizeof(struct in_addr)); 1521 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1522 off += sizeof(struct in_addr); 1523 break; 1524 1525 case IPOPT_TS_PRESPEC: 1526 if (off + sizeof(n_time) + 1527 sizeof(struct in_addr) > optlen) { 1528 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1529 goto bad; 1530 } 1531 (void)memcpy(&ipaddr.sin_addr, sin, 1532 sizeof(struct in_addr)); 1533 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1534 continue; 1535 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1536 off += sizeof(struct in_addr); 1537 break; 1538 1539 default: 1540 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1541 goto bad; 1542 } 1543 ntime = iptime(); 1544 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1545 cp[IPOPT_OFFSET] += sizeof(n_time); 1546 } 1547 } 1548 if (forward && ipforwarding) { 1549 ip_forward(m, 1, next_hop); 1550 return (1); 1551 } 1552 return (0); 1553 bad: 1554 icmp_error(m, type, code, 0, 0); 1555 ipstat.ips_badoptions++; 1556 return (1); 1557 } 1558 1559 /* 1560 * Given address of next destination (final or next hop), 1561 * return internet address info of interface to be used to get there. 1562 */ 1563 struct in_ifaddr * 1564 ip_rtaddr(dst, rt) 1565 struct in_addr dst; 1566 struct route *rt; 1567 { 1568 register struct sockaddr_in *sin; 1569 1570 sin = (struct sockaddr_in *)&rt->ro_dst; 1571 1572 if (rt->ro_rt == 0 || 1573 dst.s_addr != sin->sin_addr.s_addr) { 1574 if (rt->ro_rt) { 1575 RTFREE(rt->ro_rt); 1576 rt->ro_rt = 0; 1577 } 1578 sin->sin_family = AF_INET; 1579 sin->sin_len = sizeof(*sin); 1580 sin->sin_addr = dst; 1581 1582 rtalloc_ign(rt, RTF_PRCLONING); 1583 } 1584 if (rt->ro_rt == 0) 1585 return ((struct in_ifaddr *)0); 1586 return (ifatoia(rt->ro_rt->rt_ifa)); 1587 } 1588 1589 /* 1590 * Save incoming source route for use in replies, 1591 * to be picked up later by ip_srcroute if the receiver is interested. 1592 */ 1593 void 1594 save_rte(option, dst) 1595 u_char *option; 1596 struct in_addr dst; 1597 { 1598 unsigned olen; 1599 1600 olen = option[IPOPT_OLEN]; 1601 #ifdef DIAGNOSTIC 1602 if (ipprintfs) 1603 printf("save_rte: olen %d\n", olen); 1604 #endif 1605 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1606 return; 1607 bcopy(option, ip_srcrt.srcopt, olen); 1608 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1609 ip_srcrt.dst = dst; 1610 } 1611 1612 /* 1613 * Retrieve incoming source route for use in replies, 1614 * in the same form used by setsockopt. 1615 * The first hop is placed before the options, will be removed later. 1616 */ 1617 struct mbuf * 1618 ip_srcroute() 1619 { 1620 register struct in_addr *p, *q; 1621 register struct mbuf *m; 1622 1623 if (ip_nhops == 0) 1624 return ((struct mbuf *)0); 1625 m = m_get(M_DONTWAIT, MT_HEADER); 1626 if (m == 0) 1627 return ((struct mbuf *)0); 1628 1629 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1630 1631 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1632 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1633 OPTSIZ; 1634 #ifdef DIAGNOSTIC 1635 if (ipprintfs) 1636 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1637 #endif 1638 1639 /* 1640 * First save first hop for return route 1641 */ 1642 p = &ip_srcrt.route[ip_nhops - 1]; 1643 *(mtod(m, struct in_addr *)) = *p--; 1644 #ifdef DIAGNOSTIC 1645 if (ipprintfs) 1646 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1647 #endif 1648 1649 /* 1650 * Copy option fields and padding (nop) to mbuf. 1651 */ 1652 ip_srcrt.nop = IPOPT_NOP; 1653 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1654 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1655 &ip_srcrt.nop, OPTSIZ); 1656 q = (struct in_addr *)(mtod(m, caddr_t) + 1657 sizeof(struct in_addr) + OPTSIZ); 1658 #undef OPTSIZ 1659 /* 1660 * Record return path as an IP source route, 1661 * reversing the path (pointers are now aligned). 1662 */ 1663 while (p >= ip_srcrt.route) { 1664 #ifdef DIAGNOSTIC 1665 if (ipprintfs) 1666 printf(" %lx", (u_long)ntohl(q->s_addr)); 1667 #endif 1668 *q++ = *p--; 1669 } 1670 /* 1671 * Last hop goes to final destination. 1672 */ 1673 *q = ip_srcrt.dst; 1674 #ifdef DIAGNOSTIC 1675 if (ipprintfs) 1676 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1677 #endif 1678 return (m); 1679 } 1680 1681 /* 1682 * Strip out IP options, at higher 1683 * level protocol in the kernel. 1684 * Second argument is buffer to which options 1685 * will be moved, and return value is their length. 1686 * XXX should be deleted; last arg currently ignored. 1687 */ 1688 void 1689 ip_stripoptions(m, mopt) 1690 register struct mbuf *m; 1691 struct mbuf *mopt; 1692 { 1693 register int i; 1694 struct ip *ip = mtod(m, struct ip *); 1695 register caddr_t opts; 1696 int olen; 1697 1698 olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1699 opts = (caddr_t)(ip + 1); 1700 i = m->m_len - (sizeof (struct ip) + olen); 1701 bcopy(opts + olen, opts, (unsigned)i); 1702 m->m_len -= olen; 1703 if (m->m_flags & M_PKTHDR) 1704 m->m_pkthdr.len -= olen; 1705 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1706 } 1707 1708 u_char inetctlerrmap[PRC_NCMDS] = { 1709 0, 0, 0, 0, 1710 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1711 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1712 EMSGSIZE, EHOSTUNREACH, 0, 0, 1713 0, 0, EHOSTUNREACH, 0, 1714 ENOPROTOOPT, ECONNREFUSED 1715 }; 1716 1717 /* 1718 * Forward a packet. If some error occurs return the sender 1719 * an icmp packet. Note we can't always generate a meaningful 1720 * icmp message because icmp doesn't have a large enough repertoire 1721 * of codes and types. 1722 * 1723 * If not forwarding, just drop the packet. This could be confusing 1724 * if ipforwarding was zero but some routing protocol was advancing 1725 * us as a gateway to somewhere. However, we must let the routing 1726 * protocol deal with that. 1727 * 1728 * The srcrt parameter indicates whether the packet is being forwarded 1729 * via a source route. 1730 */ 1731 static void 1732 ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop) 1733 { 1734 struct ip *ip = mtod(m, struct ip *); 1735 struct sockaddr_in *sin; 1736 struct rtentry *rt; 1737 int error, type = 0, code = 0; 1738 struct mbuf *mcopy; 1739 n_long dest; 1740 struct in_addr pkt_dst; 1741 struct ifnet *destifp; 1742 #if defined(IPSEC) || defined(FAST_IPSEC) 1743 struct ifnet dummyifp; 1744 #endif 1745 1746 dest = 0; 1747 /* 1748 * Cache the destination address of the packet; this may be 1749 * changed by use of 'ipfw fwd'. 1750 */ 1751 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 1752 1753 #ifdef DIAGNOSTIC 1754 if (ipprintfs) 1755 printf("forward: src %lx dst %lx ttl %x\n", 1756 (u_long)ip->ip_src.s_addr, (u_long)pkt_dst.s_addr, 1757 ip->ip_ttl); 1758 #endif 1759 1760 1761 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(pkt_dst) == 0) { 1762 ipstat.ips_cantforward++; 1763 m_freem(m); 1764 return; 1765 } 1766 #ifdef IPSTEALTH 1767 if (!ipstealth) { 1768 #endif 1769 if (ip->ip_ttl <= IPTTLDEC) { 1770 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1771 dest, 0); 1772 return; 1773 } 1774 #ifdef IPSTEALTH 1775 } 1776 #endif 1777 1778 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1779 if ((rt = ipforward_rt.ro_rt) == 0 || 1780 pkt_dst.s_addr != sin->sin_addr.s_addr) { 1781 if (ipforward_rt.ro_rt) { 1782 RTFREE(ipforward_rt.ro_rt); 1783 ipforward_rt.ro_rt = 0; 1784 } 1785 sin->sin_family = AF_INET; 1786 sin->sin_len = sizeof(*sin); 1787 sin->sin_addr = pkt_dst; 1788 1789 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1790 if (ipforward_rt.ro_rt == 0) { 1791 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1792 return; 1793 } 1794 rt = ipforward_rt.ro_rt; 1795 } 1796 1797 /* 1798 * Save the IP header and at most 8 bytes of the payload, 1799 * in case we need to generate an ICMP message to the src. 1800 * 1801 * XXX this can be optimized a lot by saving the data in a local 1802 * buffer on the stack (72 bytes at most), and only allocating the 1803 * mbuf if really necessary. The vast majority of the packets 1804 * are forwarded without having to send an ICMP back (either 1805 * because unnecessary, or because rate limited), so we are 1806 * really we are wasting a lot of work here. 1807 * 1808 * We don't use m_copy() because it might return a reference 1809 * to a shared cluster. Both this function and ip_output() 1810 * assume exclusive access to the IP header in `m', so any 1811 * data in a cluster may change before we reach icmp_error(). 1812 */ 1813 MGET(mcopy, M_DONTWAIT, m->m_type); 1814 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1815 /* 1816 * It's probably ok if the pkthdr dup fails (because 1817 * the deep copy of the tag chain failed), but for now 1818 * be conservative and just discard the copy since 1819 * code below may some day want the tags. 1820 */ 1821 m_free(mcopy); 1822 mcopy = NULL; 1823 } 1824 if (mcopy != NULL) { 1825 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1826 (int)ip->ip_len); 1827 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1828 } 1829 1830 #ifdef IPSTEALTH 1831 if (!ipstealth) { 1832 #endif 1833 ip->ip_ttl -= IPTTLDEC; 1834 #ifdef IPSTEALTH 1835 } 1836 #endif 1837 1838 /* 1839 * If forwarding packet using same interface that it came in on, 1840 * perhaps should send a redirect to sender to shortcut a hop. 1841 * Only send redirect if source is sending directly to us, 1842 * and if packet was not source routed (or has any options). 1843 * Also, don't send redirect if forwarding using a default route 1844 * or a route modified by a redirect. 1845 */ 1846 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1847 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1848 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1849 ipsendredirects && !srcrt && !next_hop) { 1850 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1851 u_long src = ntohl(ip->ip_src.s_addr); 1852 1853 if (RTA(rt) && 1854 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1855 if (rt->rt_flags & RTF_GATEWAY) 1856 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1857 else 1858 dest = pkt_dst.s_addr; 1859 /* Router requirements says to only send host redirects */ 1860 type = ICMP_REDIRECT; 1861 code = ICMP_REDIRECT_HOST; 1862 #ifdef DIAGNOSTIC 1863 if (ipprintfs) 1864 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1865 #endif 1866 } 1867 } 1868 1869 { 1870 struct m_hdr tag; 1871 1872 if (next_hop) { 1873 /* Pass IPFORWARD info if available */ 1874 1875 tag.mh_type = MT_TAG; 1876 tag.mh_flags = PACKET_TAG_IPFORWARD; 1877 tag.mh_data = (caddr_t)next_hop; 1878 tag.mh_next = m; 1879 m = (struct mbuf *)&tag; 1880 } 1881 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1882 IP_FORWARDING, 0, NULL); 1883 } 1884 if (error) 1885 ipstat.ips_cantforward++; 1886 else { 1887 ipstat.ips_forward++; 1888 if (type) 1889 ipstat.ips_redirectsent++; 1890 else { 1891 if (mcopy) { 1892 ipflow_create(&ipforward_rt, mcopy); 1893 m_freem(mcopy); 1894 } 1895 return; 1896 } 1897 } 1898 if (mcopy == NULL) 1899 return; 1900 destifp = NULL; 1901 1902 switch (error) { 1903 1904 case 0: /* forwarded, but need redirect */ 1905 /* type, code set above */ 1906 break; 1907 1908 case ENETUNREACH: /* shouldn't happen, checked above */ 1909 case EHOSTUNREACH: 1910 case ENETDOWN: 1911 case EHOSTDOWN: 1912 default: 1913 type = ICMP_UNREACH; 1914 code = ICMP_UNREACH_HOST; 1915 break; 1916 1917 case EMSGSIZE: 1918 type = ICMP_UNREACH; 1919 code = ICMP_UNREACH_NEEDFRAG; 1920 #ifdef IPSEC 1921 /* 1922 * If the packet is routed over IPsec tunnel, tell the 1923 * originator the tunnel MTU. 1924 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1925 * XXX quickhack!!! 1926 */ 1927 if (ipforward_rt.ro_rt) { 1928 struct secpolicy *sp = NULL; 1929 int ipsecerror; 1930 int ipsechdr; 1931 struct route *ro; 1932 1933 sp = ipsec4_getpolicybyaddr(mcopy, 1934 IPSEC_DIR_OUTBOUND, 1935 IP_FORWARDING, 1936 &ipsecerror); 1937 1938 if (sp == NULL) 1939 destifp = ipforward_rt.ro_rt->rt_ifp; 1940 else { 1941 /* count IPsec header size */ 1942 ipsechdr = ipsec4_hdrsiz(mcopy, 1943 IPSEC_DIR_OUTBOUND, 1944 NULL); 1945 1946 /* 1947 * find the correct route for outer IPv4 1948 * header, compute tunnel MTU. 1949 * 1950 * XXX BUG ALERT 1951 * The "dummyifp" code relies upon the fact 1952 * that icmp_error() touches only ifp->if_mtu. 1953 */ 1954 /*XXX*/ 1955 destifp = NULL; 1956 if (sp->req != NULL 1957 && sp->req->sav != NULL 1958 && sp->req->sav->sah != NULL) { 1959 ro = &sp->req->sav->sah->sa_route; 1960 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1961 dummyifp.if_mtu = 1962 ro->ro_rt->rt_ifp->if_mtu; 1963 dummyifp.if_mtu -= ipsechdr; 1964 destifp = &dummyifp; 1965 } 1966 } 1967 1968 key_freesp(sp); 1969 } 1970 } 1971 #elif FAST_IPSEC 1972 /* 1973 * If the packet is routed over IPsec tunnel, tell the 1974 * originator the tunnel MTU. 1975 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1976 * XXX quickhack!!! 1977 */ 1978 if (ipforward_rt.ro_rt) { 1979 struct secpolicy *sp = NULL; 1980 int ipsecerror; 1981 int ipsechdr; 1982 struct route *ro; 1983 1984 sp = ipsec_getpolicybyaddr(mcopy, 1985 IPSEC_DIR_OUTBOUND, 1986 IP_FORWARDING, 1987 &ipsecerror); 1988 1989 if (sp == NULL) 1990 destifp = ipforward_rt.ro_rt->rt_ifp; 1991 else { 1992 /* count IPsec header size */ 1993 ipsechdr = ipsec4_hdrsiz(mcopy, 1994 IPSEC_DIR_OUTBOUND, 1995 NULL); 1996 1997 /* 1998 * find the correct route for outer IPv4 1999 * header, compute tunnel MTU. 2000 * 2001 * XXX BUG ALERT 2002 * The "dummyifp" code relies upon the fact 2003 * that icmp_error() touches only ifp->if_mtu. 2004 */ 2005 /*XXX*/ 2006 destifp = NULL; 2007 if (sp->req != NULL 2008 && sp->req->sav != NULL 2009 && sp->req->sav->sah != NULL) { 2010 ro = &sp->req->sav->sah->sa_route; 2011 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 2012 dummyifp.if_mtu = 2013 ro->ro_rt->rt_ifp->if_mtu; 2014 dummyifp.if_mtu -= ipsechdr; 2015 destifp = &dummyifp; 2016 } 2017 } 2018 2019 KEY_FREESP(&sp); 2020 } 2021 } 2022 #else /* !IPSEC && !FAST_IPSEC */ 2023 if (ipforward_rt.ro_rt) 2024 destifp = ipforward_rt.ro_rt->rt_ifp; 2025 #endif /*IPSEC*/ 2026 ipstat.ips_cantfrag++; 2027 break; 2028 2029 case ENOBUFS: 2030 /* 2031 * A router should not generate ICMP_SOURCEQUENCH as 2032 * required in RFC1812 Requirements for IP Version 4 Routers. 2033 * Source quench could be a big problem under DoS attacks, 2034 * or if the underlying interface is rate-limited. 2035 * Those who need source quench packets may re-enable them 2036 * via the net.inet.ip.sendsourcequench sysctl. 2037 */ 2038 if (ip_sendsourcequench == 0) { 2039 m_freem(mcopy); 2040 return; 2041 } else { 2042 type = ICMP_SOURCEQUENCH; 2043 code = 0; 2044 } 2045 break; 2046 2047 case EACCES: /* ipfw denied packet */ 2048 m_freem(mcopy); 2049 return; 2050 } 2051 icmp_error(mcopy, type, code, dest, destifp); 2052 } 2053 2054 void 2055 ip_savecontrol(inp, mp, ip, m) 2056 register struct inpcb *inp; 2057 register struct mbuf **mp; 2058 register struct ip *ip; 2059 register struct mbuf *m; 2060 { 2061 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2062 struct timeval tv; 2063 2064 microtime(&tv); 2065 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2066 SCM_TIMESTAMP, SOL_SOCKET); 2067 if (*mp) 2068 mp = &(*mp)->m_next; 2069 } 2070 if (inp->inp_flags & INP_RECVDSTADDR) { 2071 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2072 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2073 if (*mp) 2074 mp = &(*mp)->m_next; 2075 } 2076 #ifdef notyet 2077 /* XXX 2078 * Moving these out of udp_input() made them even more broken 2079 * than they already were. 2080 */ 2081 /* options were tossed already */ 2082 if (inp->inp_flags & INP_RECVOPTS) { 2083 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2084 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2085 if (*mp) 2086 mp = &(*mp)->m_next; 2087 } 2088 /* ip_srcroute doesn't do what we want here, need to fix */ 2089 if (inp->inp_flags & INP_RECVRETOPTS) { 2090 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2091 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2092 if (*mp) 2093 mp = &(*mp)->m_next; 2094 } 2095 #endif 2096 if (inp->inp_flags & INP_RECVIF) { 2097 struct ifnet *ifp; 2098 struct sdlbuf { 2099 struct sockaddr_dl sdl; 2100 u_char pad[32]; 2101 } sdlbuf; 2102 struct sockaddr_dl *sdp; 2103 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2104 2105 if (((ifp = m->m_pkthdr.rcvif)) 2106 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2107 sdp = (struct sockaddr_dl *)(ifnet_addrs 2108 [ifp->if_index - 1]->ifa_addr); 2109 /* 2110 * Change our mind and don't try copy. 2111 */ 2112 if ((sdp->sdl_family != AF_LINK) 2113 || (sdp->sdl_len > sizeof(sdlbuf))) { 2114 goto makedummy; 2115 } 2116 bcopy(sdp, sdl2, sdp->sdl_len); 2117 } else { 2118 makedummy: 2119 sdl2->sdl_len 2120 = offsetof(struct sockaddr_dl, sdl_data[0]); 2121 sdl2->sdl_family = AF_LINK; 2122 sdl2->sdl_index = 0; 2123 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2124 } 2125 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2126 IP_RECVIF, IPPROTO_IP); 2127 if (*mp) 2128 mp = &(*mp)->m_next; 2129 } 2130 } 2131 2132 /* 2133 * XXX these routines are called from the upper part of the kernel. 2134 * 2135 * They could also be moved to ip_mroute.c, since all the RSVP 2136 * handling is done there already. 2137 */ 2138 int 2139 ip_rsvp_init(struct socket *so) 2140 { 2141 if (so->so_type != SOCK_RAW || 2142 so->so_proto->pr_protocol != IPPROTO_RSVP) 2143 return EOPNOTSUPP; 2144 2145 if (ip_rsvpd != NULL) 2146 return EADDRINUSE; 2147 2148 ip_rsvpd = so; 2149 /* 2150 * This may seem silly, but we need to be sure we don't over-increment 2151 * the RSVP counter, in case something slips up. 2152 */ 2153 if (!ip_rsvp_on) { 2154 ip_rsvp_on = 1; 2155 rsvp_on++; 2156 } 2157 2158 return 0; 2159 } 2160 2161 int 2162 ip_rsvp_done(void) 2163 { 2164 ip_rsvpd = NULL; 2165 /* 2166 * This may seem silly, but we need to be sure we don't over-decrement 2167 * the RSVP counter, in case something slips up. 2168 */ 2169 if (ip_rsvp_on) { 2170 ip_rsvp_on = 0; 2171 rsvp_on--; 2172 } 2173 return 0; 2174 } 2175 2176 void 2177 rsvp_input(struct mbuf *m, int off, int proto) /* XXX must fixup manually */ 2178 { 2179 if (rsvp_input_p) { /* call the real one if loaded */ 2180 rsvp_input_p(m, off, proto); 2181 return; 2182 } 2183 2184 /* Can still get packets with rsvp_on = 0 if there is a local member 2185 * of the group to which the RSVP packet is addressed. But in this 2186 * case we want to throw the packet away. 2187 */ 2188 2189 if (!rsvp_on) { 2190 m_freem(m); 2191 return; 2192 } 2193 2194 if (ip_rsvpd != NULL) { 2195 rip_input(m, off, proto); 2196 return; 2197 } 2198 /* Drop the packet */ 2199 m_freem(m); 2200 } 2201
Cache object: 2e13bef08b5ab038f962bc935a45ed3a
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