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 #include "opt_bootp.h" 38 #include "opt_ipfw.h" 39 #include "opt_ipdn.h" 40 #include "opt_ipdivert.h" 41 #include "opt_ipfilter.h" 42 #include "opt_ipstealth.h" 43 #include "opt_ipsec.h" 44 #include "opt_mac.h" 45 #include "opt_pfil_hooks.h" 46 #include "opt_random_ip_id.h" 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/mac.h> 51 #include <sys/mbuf.h> 52 #include <sys/malloc.h> 53 #include <sys/domain.h> 54 #include <sys/protosw.h> 55 #include <sys/socket.h> 56 #include <sys/time.h> 57 #include <sys/kernel.h> 58 #include <sys/syslog.h> 59 #include <sys/sysctl.h> 60 61 #include <net/pfil.h> 62 #include <net/if.h> 63 #include <net/if_types.h> 64 #include <net/if_var.h> 65 #include <net/if_dl.h> 66 #include <net/route.h> 67 #include <net/netisr.h> 68 69 #include <netinet/in.h> 70 #include <netinet/in_systm.h> 71 #include <netinet/in_var.h> 72 #include <netinet/ip.h> 73 #include <netinet/in_pcb.h> 74 #include <netinet/ip_var.h> 75 #include <netinet/ip_icmp.h> 76 #include <machine/in_cksum.h> 77 78 #include <sys/socketvar.h> 79 80 #include <netinet/ip_fw.h> 81 #include <netinet/ip_dummynet.h> 82 83 #ifdef IPSEC 84 #include <netinet6/ipsec.h> 85 #include <netkey/key.h> 86 #endif 87 88 #ifdef FAST_IPSEC 89 #include <netipsec/ipsec.h> 90 #include <netipsec/key.h> 91 #endif 92 93 int rsvp_on = 0; 94 95 int ipforwarding = 0; 96 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 97 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 98 99 static int ipsendredirects = 1; /* XXX */ 100 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 101 &ipsendredirects, 0, "Enable sending IP redirects"); 102 103 int ip_defttl = IPDEFTTL; 104 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 105 &ip_defttl, 0, "Maximum TTL on IP packets"); 106 107 static int ip_dosourceroute = 0; 108 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 109 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 110 111 static int ip_acceptsourceroute = 0; 112 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 113 CTLFLAG_RW, &ip_acceptsourceroute, 0, 114 "Enable accepting source routed IP packets"); 115 116 static int ip_keepfaith = 0; 117 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 118 &ip_keepfaith, 0, 119 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 120 121 static int nipq = 0; /* total # of reass queues */ 122 static int maxnipq; 123 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 124 &maxnipq, 0, 125 "Maximum number of IPv4 fragment reassembly queue entries"); 126 127 static int maxfragsperpacket; 128 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 129 &maxfragsperpacket, 0, 130 "Maximum number of IPv4 fragments allowed per packet"); 131 132 static int ip_sendsourcequench = 0; 133 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 134 &ip_sendsourcequench, 0, 135 "Enable the transmission of source quench packets"); 136 137 /* 138 * XXX - Setting ip_checkinterface mostly implements the receive side of 139 * the Strong ES model described in RFC 1122, but since the routing table 140 * and transmit implementation do not implement the Strong ES model, 141 * setting this to 1 results in an odd hybrid. 142 * 143 * XXX - ip_checkinterface currently must be disabled if you use ipnat 144 * to translate the destination address to another local interface. 145 * 146 * XXX - ip_checkinterface must be disabled if you add IP aliases 147 * to the loopback interface instead of the interface where the 148 * packets for those addresses are received. 149 */ 150 static int ip_checkinterface = 1; 151 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 152 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 153 154 #ifdef DIAGNOSTIC 155 static int ipprintfs = 0; 156 #endif 157 158 static struct ifqueue ipintrq; 159 static int ipqmaxlen = IFQ_MAXLEN; 160 161 extern struct domain inetdomain; 162 extern struct protosw inetsw[]; 163 u_char ip_protox[IPPROTO_MAX]; 164 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 165 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 166 u_long in_ifaddrhmask; /* mask for hash table */ 167 168 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 169 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 170 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 171 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 172 173 struct ipstat ipstat; 174 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 175 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 176 177 /* Packet reassembly stuff */ 178 #define IPREASS_NHASH_LOG2 6 179 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 180 #define IPREASS_HMASK (IPREASS_NHASH - 1) 181 #define IPREASS_HASH(x,y) \ 182 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 183 184 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 185 186 #ifdef IPCTL_DEFMTU 187 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 188 &ip_mtu, 0, "Default MTU"); 189 #endif 190 191 #ifdef IPSTEALTH 192 static int ipstealth = 0; 193 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 194 &ipstealth, 0, ""); 195 #endif 196 197 198 /* Firewall hooks */ 199 ip_fw_chk_t *ip_fw_chk_ptr; 200 int fw_enable = 1 ; 201 int fw_one_pass = 1; 202 203 /* Dummynet hooks */ 204 ip_dn_io_t *ip_dn_io_ptr; 205 206 207 /* 208 * XXX this is ugly -- the following two global variables are 209 * used to store packet state while it travels through the stack. 210 * Note that the code even makes assumptions on the size and 211 * alignment of fields inside struct ip_srcrt so e.g. adding some 212 * fields will break the code. This needs to be fixed. 213 * 214 * We need to save the IP options in case a protocol wants to respond 215 * to an incoming packet over the same route if the packet got here 216 * using IP source routing. This allows connection establishment and 217 * maintenance when the remote end is on a network that is not known 218 * to us. 219 */ 220 static int ip_nhops = 0; 221 static struct ip_srcrt { 222 struct in_addr dst; /* final destination */ 223 char nop; /* one NOP to align */ 224 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 225 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 226 } ip_srcrt; 227 228 static void save_rte(u_char *, struct in_addr); 229 static int ip_dooptions(struct mbuf *m, int, 230 struct sockaddr_in *next_hop); 231 static void ip_forward(struct mbuf *m, int srcrt, 232 struct sockaddr_in *next_hop); 233 static void ip_freef(struct ipqhead *, struct ipq *); 234 static struct mbuf *ip_reass(struct mbuf *, struct ipqhead *, 235 struct ipq *, u_int32_t *, u_int16_t *); 236 237 /* 238 * IP initialization: fill in IP protocol switch table. 239 * All protocols not implemented in kernel go to raw IP protocol handler. 240 */ 241 void 242 ip_init() 243 { 244 register struct protosw *pr; 245 register int i; 246 247 TAILQ_INIT(&in_ifaddrhead); 248 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 249 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 250 if (pr == 0) 251 panic("ip_init"); 252 for (i = 0; i < IPPROTO_MAX; i++) 253 ip_protox[i] = pr - inetsw; 254 for (pr = inetdomain.dom_protosw; 255 pr < inetdomain.dom_protoswNPROTOSW; pr++) 256 if (pr->pr_domain->dom_family == PF_INET && 257 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 258 ip_protox[pr->pr_protocol] = pr - inetsw; 259 260 for (i = 0; i < IPREASS_NHASH; i++) 261 TAILQ_INIT(&ipq[i]); 262 263 maxnipq = nmbclusters / 32; 264 maxfragsperpacket = 16; 265 266 #ifndef RANDOM_IP_ID 267 ip_id = time_second & 0xffff; 268 #endif 269 ipintrq.ifq_maxlen = ipqmaxlen; 270 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 271 netisr_register(NETISR_IP, ip_input, &ipintrq); 272 } 273 274 /* 275 * XXX watch out this one. It is perhaps used as a cache for 276 * the most recently used route ? it is cleared in in_addroute() 277 * when a new route is successfully created. 278 */ 279 struct route ipforward_rt; 280 281 /* 282 * Ip input routine. Checksum and byte swap header. If fragmented 283 * try to reassemble. Process options. Pass to next level. 284 */ 285 void 286 ip_input(struct mbuf *m) 287 { 288 struct ip *ip; 289 struct ipq *fp; 290 struct in_ifaddr *ia = NULL; 291 struct ifaddr *ifa; 292 int i, hlen, checkif; 293 u_short sum; 294 struct in_addr pkt_dst; 295 u_int32_t divert_info = 0; /* packet divert/tee info */ 296 struct ip_fw_args args; 297 #ifdef PFIL_HOOKS 298 struct packet_filter_hook *pfh; 299 struct mbuf *m0; 300 int rv; 301 #endif /* PFIL_HOOKS */ 302 #ifdef FAST_IPSEC 303 struct m_tag *mtag; 304 struct tdb_ident *tdbi; 305 struct secpolicy *sp; 306 int s, error; 307 #endif /* FAST_IPSEC */ 308 309 args.eh = NULL; 310 args.oif = NULL; 311 args.rule = NULL; 312 args.divert_rule = 0; /* divert cookie */ 313 args.next_hop = NULL; 314 315 /* Grab info from MT_TAG mbufs prepended to the chain. */ 316 for (; m && m->m_type == MT_TAG; m = m->m_next) { 317 switch(m->_m_tag_id) { 318 default: 319 printf("ip_input: unrecognised MT_TAG tag %d\n", 320 m->_m_tag_id); 321 break; 322 323 case PACKET_TAG_DUMMYNET: 324 args.rule = ((struct dn_pkt *)m)->rule; 325 break; 326 327 case PACKET_TAG_DIVERT: 328 args.divert_rule = (intptr_t)m->m_hdr.mh_data & 0xffff; 329 break; 330 331 case PACKET_TAG_IPFORWARD: 332 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 333 break; 334 } 335 } 336 337 M_ASSERTPKTHDR(m); 338 339 if (args.rule) { /* dummynet already filtered us */ 340 ip = mtod(m, struct ip *); 341 hlen = ip->ip_hl << 2; 342 goto iphack ; 343 } 344 345 ipstat.ips_total++; 346 347 if (m->m_pkthdr.len < sizeof(struct ip)) 348 goto tooshort; 349 350 if (m->m_len < sizeof (struct ip) && 351 (m = m_pullup(m, sizeof (struct ip))) == 0) { 352 ipstat.ips_toosmall++; 353 return; 354 } 355 ip = mtod(m, struct ip *); 356 357 if (ip->ip_v != IPVERSION) { 358 ipstat.ips_badvers++; 359 goto bad; 360 } 361 362 hlen = ip->ip_hl << 2; 363 if (hlen < sizeof(struct ip)) { /* minimum header length */ 364 ipstat.ips_badhlen++; 365 goto bad; 366 } 367 if (hlen > m->m_len) { 368 if ((m = m_pullup(m, hlen)) == 0) { 369 ipstat.ips_badhlen++; 370 return; 371 } 372 ip = mtod(m, struct ip *); 373 } 374 375 /* 127/8 must not appear on wire - RFC1122 */ 376 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 377 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 378 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 379 ipstat.ips_badaddr++; 380 goto bad; 381 } 382 } 383 384 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 385 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 386 } else { 387 if (hlen == sizeof(struct ip)) { 388 sum = in_cksum_hdr(ip); 389 } else { 390 sum = in_cksum(m, hlen); 391 } 392 } 393 if (sum) { 394 ipstat.ips_badsum++; 395 goto bad; 396 } 397 398 /* 399 * Convert fields to host representation. 400 */ 401 ip->ip_len = ntohs(ip->ip_len); 402 if (ip->ip_len < hlen) { 403 ipstat.ips_badlen++; 404 goto bad; 405 } 406 ip->ip_off = ntohs(ip->ip_off); 407 408 /* 409 * Check that the amount of data in the buffers 410 * is as at least much as the IP header would have us expect. 411 * Trim mbufs if longer than we expect. 412 * Drop packet if shorter than we expect. 413 */ 414 if (m->m_pkthdr.len < ip->ip_len) { 415 tooshort: 416 ipstat.ips_tooshort++; 417 goto bad; 418 } 419 if (m->m_pkthdr.len > ip->ip_len) { 420 if (m->m_len == m->m_pkthdr.len) { 421 m->m_len = ip->ip_len; 422 m->m_pkthdr.len = ip->ip_len; 423 } else 424 m_adj(m, ip->ip_len - m->m_pkthdr.len); 425 } 426 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 427 /* 428 * Bypass packet filtering for packets from a tunnel (gif). 429 */ 430 if (ipsec_gethist(m, NULL)) 431 goto pass; 432 #endif 433 #if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF) 434 /* 435 * Bypass packet filtering for packets from a tunnel (gif). 436 */ 437 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 438 goto pass; 439 #endif 440 441 /* 442 * IpHack's section. 443 * Right now when no processing on packet has done 444 * and it is still fresh out of network we do our black 445 * deals with it. 446 * - Firewall: deny/allow/divert 447 * - Xlate: translate packet's addr/port (NAT). 448 * - Pipe: pass pkt through dummynet. 449 * - Wrap: fake packet's addr/port <unimpl.> 450 * - Encapsulate: put it in another IP and send out. <unimp.> 451 */ 452 453 iphack: 454 455 #ifdef PFIL_HOOKS 456 /* 457 * Run through list of hooks for input packets. If there are any 458 * filters which require that additional packets in the flow are 459 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 460 * Note that filters must _never_ set this flag, as another filter 461 * in the list may have previously cleared it. 462 */ 463 m0 = m; 464 pfh = pfil_hook_get(PFIL_IN, &inetsw[ip_protox[IPPROTO_IP]].pr_pfh); 465 for (; pfh; pfh = TAILQ_NEXT(pfh, pfil_link)) 466 if (pfh->pfil_func) { 467 rv = pfh->pfil_func(ip, hlen, 468 m->m_pkthdr.rcvif, 0, &m0); 469 if (rv) 470 return; 471 m = m0; 472 if (m == NULL) 473 return; 474 ip = mtod(m, struct ip *); 475 } 476 #endif /* PFIL_HOOKS */ 477 478 if (fw_enable && IPFW_LOADED) { 479 /* 480 * If we've been forwarded from the output side, then 481 * skip the firewall a second time 482 */ 483 if (args.next_hop) 484 goto ours; 485 486 args.m = m; 487 i = ip_fw_chk_ptr(&args); 488 m = args.m; 489 490 if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 491 if (m) 492 m_freem(m); 493 return; 494 } 495 ip = mtod(m, struct ip *); /* just in case m changed */ 496 if (i == 0 && args.next_hop == NULL) /* common case */ 497 goto pass; 498 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) { 499 /* Send packet to the appropriate pipe */ 500 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 501 return; 502 } 503 #ifdef IPDIVERT 504 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 505 /* Divert or tee packet */ 506 divert_info = i; 507 goto ours; 508 } 509 #endif 510 if (i == 0 && args.next_hop != NULL) 511 goto pass; 512 /* 513 * if we get here, the packet must be dropped 514 */ 515 m_freem(m); 516 return; 517 } 518 pass: 519 520 /* 521 * Process options and, if not destined for us, 522 * ship it on. ip_dooptions returns 1 when an 523 * error was detected (causing an icmp message 524 * to be sent and the original packet to be freed). 525 */ 526 ip_nhops = 0; /* for source routed packets */ 527 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, args.next_hop)) 528 return; 529 530 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 531 * matter if it is destined to another node, or whether it is 532 * a multicast one, RSVP wants it! and prevents it from being forwarded 533 * anywhere else. Also checks if the rsvp daemon is running before 534 * grabbing the packet. 535 */ 536 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 537 goto ours; 538 539 /* 540 * Check our list of addresses, to see if the packet is for us. 541 * If we don't have any addresses, assume any unicast packet 542 * we receive might be for us (and let the upper layers deal 543 * with it). 544 */ 545 if (TAILQ_EMPTY(&in_ifaddrhead) && 546 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 547 goto ours; 548 549 /* 550 * Cache the destination address of the packet; this may be 551 * changed by use of 'ipfw fwd'. 552 */ 553 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 554 555 /* 556 * Enable a consistency check between the destination address 557 * and the arrival interface for a unicast packet (the RFC 1122 558 * strong ES model) if IP forwarding is disabled and the packet 559 * is not locally generated and the packet is not subject to 560 * 'ipfw fwd'. 561 * 562 * XXX - Checking also should be disabled if the destination 563 * address is ipnat'ed to a different interface. 564 * 565 * XXX - Checking is incompatible with IP aliases added 566 * to the loopback interface instead of the interface where 567 * the packets are received. 568 */ 569 checkif = ip_checkinterface && (ipforwarding == 0) && 570 m->m_pkthdr.rcvif != NULL && 571 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 572 (args.next_hop == NULL); 573 574 /* 575 * Check for exact addresses in the hash bucket. 576 */ 577 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 578 /* 579 * If the address matches, verify that the packet 580 * arrived via the correct interface if checking is 581 * enabled. 582 */ 583 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 584 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 585 goto ours; 586 } 587 /* 588 * Check for broadcast addresses. 589 * 590 * Only accept broadcast packets that arrive via the matching 591 * interface. Reception of forwarded directed broadcasts would 592 * be handled via ip_forward() and ether_output() with the loopback 593 * into the stack for SIMPLEX interfaces handled by ether_output(). 594 */ 595 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 596 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 597 if (ifa->ifa_addr->sa_family != AF_INET) 598 continue; 599 ia = ifatoia(ifa); 600 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 601 pkt_dst.s_addr) 602 goto ours; 603 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 604 goto ours; 605 #ifdef BOOTP_COMPAT 606 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 607 goto ours; 608 #endif 609 } 610 } 611 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 612 struct in_multi *inm; 613 if (ip_mrouter) { 614 /* 615 * If we are acting as a multicast router, all 616 * incoming multicast packets are passed to the 617 * kernel-level multicast forwarding function. 618 * The packet is returned (relatively) intact; if 619 * ip_mforward() returns a non-zero value, the packet 620 * must be discarded, else it may be accepted below. 621 */ 622 if (ip_mforward && 623 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 624 ipstat.ips_cantforward++; 625 m_freem(m); 626 return; 627 } 628 629 /* 630 * The process-level routing daemon needs to receive 631 * all multicast IGMP packets, whether or not this 632 * host belongs to their destination groups. 633 */ 634 if (ip->ip_p == IPPROTO_IGMP) 635 goto ours; 636 ipstat.ips_forward++; 637 } 638 /* 639 * See if we belong to the destination multicast group on the 640 * arrival interface. 641 */ 642 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 643 if (inm == NULL) { 644 ipstat.ips_notmember++; 645 m_freem(m); 646 return; 647 } 648 goto ours; 649 } 650 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 651 goto ours; 652 if (ip->ip_dst.s_addr == INADDR_ANY) 653 goto ours; 654 655 /* 656 * FAITH(Firewall Aided Internet Translator) 657 */ 658 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 659 if (ip_keepfaith) { 660 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 661 goto ours; 662 } 663 m_freem(m); 664 return; 665 } 666 667 /* 668 * Not for us; forward if possible and desirable. 669 */ 670 if (ipforwarding == 0) { 671 ipstat.ips_cantforward++; 672 m_freem(m); 673 } else { 674 #ifdef IPSEC 675 /* 676 * Enforce inbound IPsec SPD. 677 */ 678 if (ipsec4_in_reject(m, NULL)) { 679 ipsecstat.in_polvio++; 680 goto bad; 681 } 682 #endif /* IPSEC */ 683 #ifdef FAST_IPSEC 684 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 685 s = splnet(); 686 if (mtag != NULL) { 687 tdbi = (struct tdb_ident *)(mtag + 1); 688 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 689 } else { 690 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 691 IP_FORWARDING, &error); 692 } 693 if (sp == NULL) { /* NB: can happen if error */ 694 splx(s); 695 /*XXX error stat???*/ 696 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 697 goto bad; 698 } 699 700 /* 701 * Check security policy against packet attributes. 702 */ 703 error = ipsec_in_reject(sp, m); 704 KEY_FREESP(&sp); 705 splx(s); 706 if (error) { 707 ipstat.ips_cantforward++; 708 goto bad; 709 } 710 #endif /* FAST_IPSEC */ 711 ip_forward(m, 0, args.next_hop); 712 } 713 return; 714 715 ours: 716 #ifdef IPSTEALTH 717 /* 718 * IPSTEALTH: Process non-routing options only 719 * if the packet is destined for us. 720 */ 721 if (ipstealth && hlen > sizeof (struct ip) && 722 ip_dooptions(m, 1, args.next_hop)) 723 return; 724 #endif /* IPSTEALTH */ 725 726 /* Count the packet in the ip address stats */ 727 if (ia != NULL) { 728 ia->ia_ifa.if_ipackets++; 729 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 730 } 731 732 /* 733 * If offset or IP_MF are set, must reassemble. 734 * Otherwise, nothing need be done. 735 * (We could look in the reassembly queue to see 736 * if the packet was previously fragmented, 737 * but it's not worth the time; just let them time out.) 738 */ 739 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 740 741 /* If maxnipq is 0, never accept fragments. */ 742 if (maxnipq == 0) { 743 ipstat.ips_fragments++; 744 ipstat.ips_fragdropped++; 745 goto bad; 746 } 747 748 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 749 /* 750 * Look for queue of fragments 751 * of this datagram. 752 */ 753 TAILQ_FOREACH(fp, &ipq[sum], ipq_list) 754 if (ip->ip_id == fp->ipq_id && 755 ip->ip_src.s_addr == fp->ipq_src.s_addr && 756 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 757 #ifdef MAC 758 mac_fragment_match(m, fp) && 759 #endif 760 ip->ip_p == fp->ipq_p) 761 goto found; 762 763 fp = NULL; 764 765 /* 766 * Enforce upper bound on number of fragmented packets 767 * for which we attempt reassembly; 768 * If maxnipq is -1, accept all fragments without limitation. 769 */ 770 if ((nipq > maxnipq) && (maxnipq > 0)) { 771 /* 772 * drop something from the tail of the current queue 773 * before proceeding further 774 */ 775 struct ipq *q = TAILQ_LAST(&ipq[sum], ipqhead); 776 if (q == NULL) { /* gak */ 777 for (i = 0; i < IPREASS_NHASH; i++) { 778 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 779 if (r) { 780 ipstat.ips_fragtimeout += r->ipq_nfrags; 781 ip_freef(&ipq[i], r); 782 break; 783 } 784 } 785 } else { 786 ipstat.ips_fragtimeout += q->ipq_nfrags; 787 ip_freef(&ipq[sum], q); 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 &ipq[sum], fp, &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->ip_hl << 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); 949 } else 950 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 951 return; 952 bad: 953 m_freem(m); 954 } 955 956 /* 957 * Take incoming datagram fragment and try to reassemble it into 958 * whole datagram. If a chain for reassembly of this datagram already 959 * exists, then it is given as fp; otherwise have to make a chain. 960 * 961 * When IPDIVERT enabled, keep additional state with each packet that 962 * tells us if we need to divert or tee the packet we're building. 963 * In particular, *divinfo includes the port and TEE flag, 964 * *divert_rule is the number of the matching rule. 965 */ 966 967 static struct mbuf * 968 ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp, 969 u_int32_t *divinfo, u_int16_t *divert_rule) 970 { 971 struct ip *ip = mtod(m, struct ip *); 972 register struct mbuf *p, *q, *nq; 973 struct mbuf *t; 974 int hlen = ip->ip_hl << 2; 975 int i, next; 976 977 /* 978 * Presence of header sizes in mbufs 979 * would confuse code below. 980 */ 981 m->m_data += hlen; 982 m->m_len -= hlen; 983 984 /* 985 * If first fragment to arrive, create a reassembly queue. 986 */ 987 if (fp == NULL) { 988 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 989 goto dropfrag; 990 fp = mtod(t, struct ipq *); 991 #ifdef MAC 992 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 993 m_free(t); 994 goto dropfrag; 995 } 996 mac_create_ipq(m, fp); 997 #endif 998 TAILQ_INSERT_HEAD(head, fp, ipq_list); 999 nipq++; 1000 fp->ipq_nfrags = 1; 1001 fp->ipq_ttl = IPFRAGTTL; 1002 fp->ipq_p = ip->ip_p; 1003 fp->ipq_id = ip->ip_id; 1004 fp->ipq_src = ip->ip_src; 1005 fp->ipq_dst = ip->ip_dst; 1006 fp->ipq_frags = m; 1007 m->m_nextpkt = NULL; 1008 #ifdef IPDIVERT 1009 fp->ipq_div_info = 0; 1010 fp->ipq_div_cookie = 0; 1011 #endif 1012 goto inserted; 1013 } else { 1014 fp->ipq_nfrags++; 1015 #ifdef MAC 1016 mac_update_ipq(m, fp); 1017 #endif 1018 } 1019 1020 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1021 1022 /* 1023 * Find a segment which begins after this one does. 1024 */ 1025 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1026 if (GETIP(q)->ip_off > ip->ip_off) 1027 break; 1028 1029 /* 1030 * If there is a preceding segment, it may provide some of 1031 * our data already. If so, drop the data from the incoming 1032 * segment. If it provides all of our data, drop us, otherwise 1033 * stick new segment in the proper place. 1034 * 1035 * If some of the data is dropped from the the preceding 1036 * segment, then it's checksum is invalidated. 1037 */ 1038 if (p) { 1039 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1040 if (i > 0) { 1041 if (i >= ip->ip_len) 1042 goto dropfrag; 1043 m_adj(m, i); 1044 m->m_pkthdr.csum_flags = 0; 1045 ip->ip_off += i; 1046 ip->ip_len -= i; 1047 } 1048 m->m_nextpkt = p->m_nextpkt; 1049 p->m_nextpkt = m; 1050 } else { 1051 m->m_nextpkt = fp->ipq_frags; 1052 fp->ipq_frags = m; 1053 } 1054 1055 /* 1056 * While we overlap succeeding segments trim them or, 1057 * if they are completely covered, dequeue them. 1058 */ 1059 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1060 q = nq) { 1061 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1062 if (i < GETIP(q)->ip_len) { 1063 GETIP(q)->ip_len -= i; 1064 GETIP(q)->ip_off += i; 1065 m_adj(q, i); 1066 q->m_pkthdr.csum_flags = 0; 1067 break; 1068 } 1069 nq = q->m_nextpkt; 1070 m->m_nextpkt = nq; 1071 ipstat.ips_fragdropped++; 1072 fp->ipq_nfrags--; 1073 m_freem(q); 1074 } 1075 1076 inserted: 1077 1078 #ifdef IPDIVERT 1079 /* 1080 * Transfer firewall instructions to the fragment structure. 1081 * Only trust info in the fragment at offset 0. 1082 */ 1083 if (ip->ip_off == 0) { 1084 fp->ipq_div_info = *divinfo; 1085 fp->ipq_div_cookie = *divert_rule; 1086 } 1087 *divinfo = 0; 1088 *divert_rule = 0; 1089 #endif 1090 1091 /* 1092 * Check for complete reassembly and perform frag per packet 1093 * limiting. 1094 * 1095 * Frag limiting is performed here so that the nth frag has 1096 * a chance to complete the packet before we drop the packet. 1097 * As a result, n+1 frags are actually allowed per packet, but 1098 * only n will ever be stored. (n = maxfragsperpacket.) 1099 * 1100 */ 1101 next = 0; 1102 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1103 if (GETIP(q)->ip_off != next) { 1104 if (fp->ipq_nfrags > maxfragsperpacket) { 1105 ipstat.ips_fragdropped += fp->ipq_nfrags; 1106 ip_freef(head, fp); 1107 } 1108 return (0); 1109 } 1110 next += GETIP(q)->ip_len; 1111 } 1112 /* Make sure the last packet didn't have the IP_MF flag */ 1113 if (p->m_flags & M_FRAG) { 1114 if (fp->ipq_nfrags > maxfragsperpacket) { 1115 ipstat.ips_fragdropped += fp->ipq_nfrags; 1116 ip_freef(head, fp); 1117 } 1118 return (0); 1119 } 1120 1121 /* 1122 * Reassembly is complete. Make sure the packet is a sane size. 1123 */ 1124 q = fp->ipq_frags; 1125 ip = GETIP(q); 1126 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1127 ipstat.ips_toolong++; 1128 ipstat.ips_fragdropped += fp->ipq_nfrags; 1129 ip_freef(head, fp); 1130 return (0); 1131 } 1132 1133 /* 1134 * Concatenate fragments. 1135 */ 1136 m = q; 1137 t = m->m_next; 1138 m->m_next = 0; 1139 m_cat(m, t); 1140 nq = q->m_nextpkt; 1141 q->m_nextpkt = 0; 1142 for (q = nq; q != NULL; q = nq) { 1143 nq = q->m_nextpkt; 1144 q->m_nextpkt = NULL; 1145 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1146 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1147 m_cat(m, q); 1148 } 1149 #ifdef MAC 1150 mac_create_datagram_from_ipq(fp, m); 1151 mac_destroy_ipq(fp); 1152 #endif 1153 1154 #ifdef IPDIVERT 1155 /* 1156 * Extract firewall instructions from the fragment structure. 1157 */ 1158 *divinfo = fp->ipq_div_info; 1159 *divert_rule = fp->ipq_div_cookie; 1160 #endif 1161 1162 /* 1163 * Create header for new ip packet by 1164 * modifying header of first packet; 1165 * dequeue and discard fragment reassembly header. 1166 * Make header visible. 1167 */ 1168 ip->ip_len = next; 1169 ip->ip_src = fp->ipq_src; 1170 ip->ip_dst = fp->ipq_dst; 1171 TAILQ_REMOVE(head, fp, ipq_list); 1172 nipq--; 1173 (void) m_free(dtom(fp)); 1174 m->m_len += (ip->ip_hl << 2); 1175 m->m_data -= (ip->ip_hl << 2); 1176 /* some debugging cruft by sklower, below, will go away soon */ 1177 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1178 m_fixhdr(m); 1179 return (m); 1180 1181 dropfrag: 1182 #ifdef IPDIVERT 1183 *divinfo = 0; 1184 *divert_rule = 0; 1185 #endif 1186 ipstat.ips_fragdropped++; 1187 if (fp != NULL) 1188 fp->ipq_nfrags--; 1189 m_freem(m); 1190 return (0); 1191 1192 #undef GETIP 1193 } 1194 1195 /* 1196 * Free a fragment reassembly header and all 1197 * associated datagrams. 1198 */ 1199 static void 1200 ip_freef(fhp, fp) 1201 struct ipqhead *fhp; 1202 struct ipq *fp; 1203 { 1204 register struct mbuf *q; 1205 1206 while (fp->ipq_frags) { 1207 q = fp->ipq_frags; 1208 fp->ipq_frags = q->m_nextpkt; 1209 m_freem(q); 1210 } 1211 TAILQ_REMOVE(fhp, fp, ipq_list); 1212 (void) m_free(dtom(fp)); 1213 nipq--; 1214 } 1215 1216 /* 1217 * IP timer processing; 1218 * if a timer expires on a reassembly 1219 * queue, discard it. 1220 */ 1221 void 1222 ip_slowtimo() 1223 { 1224 register struct ipq *fp; 1225 int s = splnet(); 1226 int i; 1227 1228 for (i = 0; i < IPREASS_NHASH; i++) { 1229 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1230 struct ipq *fpp; 1231 1232 fpp = fp; 1233 fp = TAILQ_NEXT(fp, ipq_list); 1234 if(--fpp->ipq_ttl == 0) { 1235 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1236 ip_freef(&ipq[i], fpp); 1237 } 1238 } 1239 } 1240 /* 1241 * If we are over the maximum number of fragments 1242 * (due to the limit being lowered), drain off 1243 * enough to get down to the new limit. 1244 */ 1245 if (maxnipq >= 0 && nipq > maxnipq) { 1246 for (i = 0; i < IPREASS_NHASH; i++) { 1247 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1248 ipstat.ips_fragdropped += 1249 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1250 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1251 } 1252 } 1253 } 1254 ipflow_slowtimo(); 1255 splx(s); 1256 } 1257 1258 /* 1259 * Drain off all datagram fragments. 1260 */ 1261 void 1262 ip_drain() 1263 { 1264 int i; 1265 1266 for (i = 0; i < IPREASS_NHASH; i++) { 1267 while(!TAILQ_EMPTY(&ipq[i])) { 1268 ipstat.ips_fragdropped += 1269 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1270 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1271 } 1272 } 1273 in_rtqdrain(); 1274 } 1275 1276 /* 1277 * Do option processing on a datagram, 1278 * possibly discarding it if bad options are encountered, 1279 * or forwarding it if source-routed. 1280 * The pass argument is used when operating in the IPSTEALTH 1281 * mode to tell what options to process: 1282 * [LS]SRR (pass 0) or the others (pass 1). 1283 * The reason for as many as two passes is that when doing IPSTEALTH, 1284 * non-routing options should be processed only if the packet is for us. 1285 * Returns 1 if packet has been forwarded/freed, 1286 * 0 if the packet should be processed further. 1287 */ 1288 static int 1289 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1290 { 1291 struct ip *ip = mtod(m, struct ip *); 1292 u_char *cp; 1293 struct in_ifaddr *ia; 1294 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1295 struct in_addr *sin, dst; 1296 n_time ntime; 1297 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 1298 1299 dst = ip->ip_dst; 1300 cp = (u_char *)(ip + 1); 1301 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1302 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1303 opt = cp[IPOPT_OPTVAL]; 1304 if (opt == IPOPT_EOL) 1305 break; 1306 if (opt == IPOPT_NOP) 1307 optlen = 1; 1308 else { 1309 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1310 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1311 goto bad; 1312 } 1313 optlen = cp[IPOPT_OLEN]; 1314 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1315 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1316 goto bad; 1317 } 1318 } 1319 switch (opt) { 1320 1321 default: 1322 break; 1323 1324 /* 1325 * Source routing with record. 1326 * Find interface with current destination address. 1327 * If none on this machine then drop if strictly routed, 1328 * or do nothing if loosely routed. 1329 * Record interface address and bring up next address 1330 * component. If strictly routed make sure next 1331 * address is on directly accessible net. 1332 */ 1333 case IPOPT_LSRR: 1334 case IPOPT_SSRR: 1335 #ifdef IPSTEALTH 1336 if (ipstealth && pass > 0) 1337 break; 1338 #endif 1339 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1340 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1341 goto bad; 1342 } 1343 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1344 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1345 goto bad; 1346 } 1347 ipaddr.sin_addr = ip->ip_dst; 1348 ia = (struct in_ifaddr *) 1349 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1350 if (ia == 0) { 1351 if (opt == IPOPT_SSRR) { 1352 type = ICMP_UNREACH; 1353 code = ICMP_UNREACH_SRCFAIL; 1354 goto bad; 1355 } 1356 if (!ip_dosourceroute) 1357 goto nosourcerouting; 1358 /* 1359 * Loose routing, and not at next destination 1360 * yet; nothing to do except forward. 1361 */ 1362 break; 1363 } 1364 off--; /* 0 origin */ 1365 if (off > optlen - (int)sizeof(struct in_addr)) { 1366 /* 1367 * End of source route. Should be for us. 1368 */ 1369 if (!ip_acceptsourceroute) 1370 goto nosourcerouting; 1371 save_rte(cp, ip->ip_src); 1372 break; 1373 } 1374 #ifdef IPSTEALTH 1375 if (ipstealth) 1376 goto dropit; 1377 #endif 1378 if (!ip_dosourceroute) { 1379 if (ipforwarding) { 1380 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1381 /* 1382 * Acting as a router, so generate ICMP 1383 */ 1384 nosourcerouting: 1385 strcpy(buf, inet_ntoa(ip->ip_dst)); 1386 log(LOG_WARNING, 1387 "attempted source route from %s to %s\n", 1388 inet_ntoa(ip->ip_src), buf); 1389 type = ICMP_UNREACH; 1390 code = ICMP_UNREACH_SRCFAIL; 1391 goto bad; 1392 } else { 1393 /* 1394 * Not acting as a router, so silently drop. 1395 */ 1396 #ifdef IPSTEALTH 1397 dropit: 1398 #endif 1399 ipstat.ips_cantforward++; 1400 m_freem(m); 1401 return (1); 1402 } 1403 } 1404 1405 /* 1406 * locate outgoing interface 1407 */ 1408 (void)memcpy(&ipaddr.sin_addr, cp + off, 1409 sizeof(ipaddr.sin_addr)); 1410 1411 if (opt == IPOPT_SSRR) { 1412 #define INA struct in_ifaddr * 1413 #define SA struct sockaddr * 1414 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1415 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1416 } else 1417 ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt); 1418 if (ia == 0) { 1419 type = ICMP_UNREACH; 1420 code = ICMP_UNREACH_SRCFAIL; 1421 goto bad; 1422 } 1423 ip->ip_dst = ipaddr.sin_addr; 1424 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1425 sizeof(struct in_addr)); 1426 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1427 /* 1428 * Let ip_intr's mcast routing check handle mcast pkts 1429 */ 1430 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1431 break; 1432 1433 case IPOPT_RR: 1434 #ifdef IPSTEALTH 1435 if (ipstealth && pass == 0) 1436 break; 1437 #endif 1438 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1439 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1440 goto bad; 1441 } 1442 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1443 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1444 goto bad; 1445 } 1446 /* 1447 * If no space remains, ignore. 1448 */ 1449 off--; /* 0 origin */ 1450 if (off > optlen - (int)sizeof(struct in_addr)) 1451 break; 1452 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1453 sizeof(ipaddr.sin_addr)); 1454 /* 1455 * locate outgoing interface; if we're the destination, 1456 * use the incoming interface (should be same). 1457 */ 1458 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1459 (ia = ip_rtaddr(ipaddr.sin_addr, 1460 &ipforward_rt)) == 0) { 1461 type = ICMP_UNREACH; 1462 code = ICMP_UNREACH_HOST; 1463 goto bad; 1464 } 1465 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1466 sizeof(struct in_addr)); 1467 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1468 break; 1469 1470 case IPOPT_TS: 1471 #ifdef IPSTEALTH 1472 if (ipstealth && pass == 0) 1473 break; 1474 #endif 1475 code = cp - (u_char *)ip; 1476 if (optlen < 4 || optlen > 40) { 1477 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1478 goto bad; 1479 } 1480 if ((off = cp[IPOPT_OFFSET]) < 5) { 1481 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1482 goto bad; 1483 } 1484 if (off > optlen - (int)sizeof(int32_t)) { 1485 cp[IPOPT_OFFSET + 1] += (1 << 4); 1486 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1487 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1488 goto bad; 1489 } 1490 break; 1491 } 1492 off--; /* 0 origin */ 1493 sin = (struct in_addr *)(cp + off); 1494 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1495 1496 case IPOPT_TS_TSONLY: 1497 break; 1498 1499 case IPOPT_TS_TSANDADDR: 1500 if (off + sizeof(n_time) + 1501 sizeof(struct in_addr) > optlen) { 1502 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1503 goto bad; 1504 } 1505 ipaddr.sin_addr = dst; 1506 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1507 m->m_pkthdr.rcvif); 1508 if (ia == 0) 1509 continue; 1510 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1511 sizeof(struct in_addr)); 1512 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1513 off += sizeof(struct in_addr); 1514 break; 1515 1516 case IPOPT_TS_PRESPEC: 1517 if (off + sizeof(n_time) + 1518 sizeof(struct in_addr) > optlen) { 1519 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1520 goto bad; 1521 } 1522 (void)memcpy(&ipaddr.sin_addr, sin, 1523 sizeof(struct in_addr)); 1524 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1525 continue; 1526 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1527 off += sizeof(struct in_addr); 1528 break; 1529 1530 default: 1531 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1532 goto bad; 1533 } 1534 ntime = iptime(); 1535 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1536 cp[IPOPT_OFFSET] += sizeof(n_time); 1537 } 1538 } 1539 if (forward && ipforwarding) { 1540 ip_forward(m, 1, next_hop); 1541 return (1); 1542 } 1543 return (0); 1544 bad: 1545 icmp_error(m, type, code, 0, 0); 1546 ipstat.ips_badoptions++; 1547 return (1); 1548 } 1549 1550 /* 1551 * Given address of next destination (final or next hop), 1552 * return internet address info of interface to be used to get there. 1553 */ 1554 struct in_ifaddr * 1555 ip_rtaddr(dst, rt) 1556 struct in_addr dst; 1557 struct route *rt; 1558 { 1559 register struct sockaddr_in *sin; 1560 1561 sin = (struct sockaddr_in *)&rt->ro_dst; 1562 1563 if (rt->ro_rt == 0 || 1564 !(rt->ro_rt->rt_flags & RTF_UP) || 1565 dst.s_addr != sin->sin_addr.s_addr) { 1566 if (rt->ro_rt) { 1567 RTFREE(rt->ro_rt); 1568 rt->ro_rt = 0; 1569 } 1570 sin->sin_family = AF_INET; 1571 sin->sin_len = sizeof(*sin); 1572 sin->sin_addr = dst; 1573 1574 rtalloc_ign(rt, RTF_PRCLONING); 1575 } 1576 if (rt->ro_rt == 0) 1577 return ((struct in_ifaddr *)0); 1578 return (ifatoia(rt->ro_rt->rt_ifa)); 1579 } 1580 1581 /* 1582 * Save incoming source route for use in replies, 1583 * to be picked up later by ip_srcroute if the receiver is interested. 1584 */ 1585 static void 1586 save_rte(option, dst) 1587 u_char *option; 1588 struct in_addr dst; 1589 { 1590 unsigned olen; 1591 1592 olen = option[IPOPT_OLEN]; 1593 #ifdef DIAGNOSTIC 1594 if (ipprintfs) 1595 printf("save_rte: olen %d\n", olen); 1596 #endif 1597 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1598 return; 1599 bcopy(option, ip_srcrt.srcopt, olen); 1600 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1601 ip_srcrt.dst = dst; 1602 } 1603 1604 /* 1605 * Retrieve incoming source route for use in replies, 1606 * in the same form used by setsockopt. 1607 * The first hop is placed before the options, will be removed later. 1608 */ 1609 struct mbuf * 1610 ip_srcroute() 1611 { 1612 register struct in_addr *p, *q; 1613 register struct mbuf *m; 1614 1615 if (ip_nhops == 0) 1616 return ((struct mbuf *)0); 1617 m = m_get(M_DONTWAIT, MT_HEADER); 1618 if (m == 0) 1619 return ((struct mbuf *)0); 1620 1621 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1622 1623 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1624 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1625 OPTSIZ; 1626 #ifdef DIAGNOSTIC 1627 if (ipprintfs) 1628 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1629 #endif 1630 1631 /* 1632 * First save first hop for return route 1633 */ 1634 p = &ip_srcrt.route[ip_nhops - 1]; 1635 *(mtod(m, struct in_addr *)) = *p--; 1636 #ifdef DIAGNOSTIC 1637 if (ipprintfs) 1638 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1639 #endif 1640 1641 /* 1642 * Copy option fields and padding (nop) to mbuf. 1643 */ 1644 ip_srcrt.nop = IPOPT_NOP; 1645 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1646 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1647 &ip_srcrt.nop, OPTSIZ); 1648 q = (struct in_addr *)(mtod(m, caddr_t) + 1649 sizeof(struct in_addr) + OPTSIZ); 1650 #undef OPTSIZ 1651 /* 1652 * Record return path as an IP source route, 1653 * reversing the path (pointers are now aligned). 1654 */ 1655 while (p >= ip_srcrt.route) { 1656 #ifdef DIAGNOSTIC 1657 if (ipprintfs) 1658 printf(" %lx", (u_long)ntohl(q->s_addr)); 1659 #endif 1660 *q++ = *p--; 1661 } 1662 /* 1663 * Last hop goes to final destination. 1664 */ 1665 *q = ip_srcrt.dst; 1666 #ifdef DIAGNOSTIC 1667 if (ipprintfs) 1668 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1669 #endif 1670 return (m); 1671 } 1672 1673 /* 1674 * Strip out IP options, at higher 1675 * level protocol in the kernel. 1676 * Second argument is buffer to which options 1677 * will be moved, and return value is their length. 1678 * XXX should be deleted; last arg currently ignored. 1679 */ 1680 void 1681 ip_stripoptions(m, mopt) 1682 register struct mbuf *m; 1683 struct mbuf *mopt; 1684 { 1685 register int i; 1686 struct ip *ip = mtod(m, struct ip *); 1687 register caddr_t opts; 1688 int olen; 1689 1690 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1691 opts = (caddr_t)(ip + 1); 1692 i = m->m_len - (sizeof (struct ip) + olen); 1693 bcopy(opts + olen, opts, (unsigned)i); 1694 m->m_len -= olen; 1695 if (m->m_flags & M_PKTHDR) 1696 m->m_pkthdr.len -= olen; 1697 ip->ip_v = IPVERSION; 1698 ip->ip_hl = sizeof(struct ip) >> 2; 1699 } 1700 1701 u_char inetctlerrmap[PRC_NCMDS] = { 1702 0, 0, 0, 0, 1703 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1704 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1705 EMSGSIZE, EHOSTUNREACH, 0, 0, 1706 0, 0, EHOSTUNREACH, 0, 1707 ENOPROTOOPT, ECONNREFUSED 1708 }; 1709 1710 /* 1711 * Forward a packet. If some error occurs return the sender 1712 * an icmp packet. Note we can't always generate a meaningful 1713 * icmp message because icmp doesn't have a large enough repertoire 1714 * of codes and types. 1715 * 1716 * If not forwarding, just drop the packet. This could be confusing 1717 * if ipforwarding was zero but some routing protocol was advancing 1718 * us as a gateway to somewhere. However, we must let the routing 1719 * protocol deal with that. 1720 * 1721 * The srcrt parameter indicates whether the packet is being forwarded 1722 * via a source route. 1723 */ 1724 static void 1725 ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop) 1726 { 1727 struct ip *ip = mtod(m, struct ip *); 1728 struct rtentry *rt; 1729 int error, type = 0, code = 0; 1730 struct mbuf *mcopy; 1731 n_long dest; 1732 struct in_addr pkt_dst; 1733 struct ifnet *destifp; 1734 #if defined(IPSEC) || defined(FAST_IPSEC) 1735 struct ifnet dummyifp; 1736 #endif 1737 1738 dest = 0; 1739 /* 1740 * Cache the destination address of the packet; this may be 1741 * changed by use of 'ipfw fwd'. 1742 */ 1743 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 1744 1745 #ifdef DIAGNOSTIC 1746 if (ipprintfs) 1747 printf("forward: src %lx dst %lx ttl %x\n", 1748 (u_long)ip->ip_src.s_addr, (u_long)pkt_dst.s_addr, 1749 ip->ip_ttl); 1750 #endif 1751 1752 1753 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(pkt_dst) == 0) { 1754 ipstat.ips_cantforward++; 1755 m_freem(m); 1756 return; 1757 } 1758 #ifdef IPSTEALTH 1759 if (!ipstealth) { 1760 #endif 1761 if (ip->ip_ttl <= IPTTLDEC) { 1762 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1763 dest, 0); 1764 return; 1765 } 1766 #ifdef IPSTEALTH 1767 } 1768 #endif 1769 1770 if (ip_rtaddr(pkt_dst, &ipforward_rt) == 0) { 1771 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1772 return; 1773 } else 1774 rt = ipforward_rt.ro_rt; 1775 1776 /* 1777 * Save the IP header and at most 8 bytes of the payload, 1778 * in case we need to generate an ICMP message to the src. 1779 * 1780 * XXX this can be optimized a lot by saving the data in a local 1781 * buffer on the stack (72 bytes at most), and only allocating the 1782 * mbuf if really necessary. The vast majority of the packets 1783 * are forwarded without having to send an ICMP back (either 1784 * because unnecessary, or because rate limited), so we are 1785 * really we are wasting a lot of work here. 1786 * 1787 * We don't use m_copy() because it might return a reference 1788 * to a shared cluster. Both this function and ip_output() 1789 * assume exclusive access to the IP header in `m', so any 1790 * data in a cluster may change before we reach icmp_error(). 1791 */ 1792 MGET(mcopy, M_DONTWAIT, m->m_type); 1793 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1794 /* 1795 * It's probably ok if the pkthdr dup fails (because 1796 * the deep copy of the tag chain failed), but for now 1797 * be conservative and just discard the copy since 1798 * code below may some day want the tags. 1799 */ 1800 m_free(mcopy); 1801 mcopy = NULL; 1802 } 1803 if (mcopy != NULL) { 1804 mcopy->m_len = imin((ip->ip_hl << 2) + 8, 1805 (int)ip->ip_len); 1806 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1807 /* 1808 * XXXMAC: Eventually, we may have an explict labeling 1809 * point here. 1810 */ 1811 } 1812 1813 #ifdef IPSTEALTH 1814 if (!ipstealth) { 1815 #endif 1816 ip->ip_ttl -= IPTTLDEC; 1817 #ifdef IPSTEALTH 1818 } 1819 #endif 1820 1821 /* 1822 * If forwarding packet using same interface that it came in on, 1823 * perhaps should send a redirect to sender to shortcut a hop. 1824 * Only send redirect if source is sending directly to us, 1825 * and if packet was not source routed (or has any options). 1826 * Also, don't send redirect if forwarding using a default route 1827 * or a route modified by a redirect. 1828 */ 1829 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1830 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1831 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1832 ipsendredirects && !srcrt && !next_hop) { 1833 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1834 u_long src = ntohl(ip->ip_src.s_addr); 1835 1836 if (RTA(rt) && 1837 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1838 if (rt->rt_flags & RTF_GATEWAY) 1839 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1840 else 1841 dest = pkt_dst.s_addr; 1842 /* Router requirements says to only send host redirects */ 1843 type = ICMP_REDIRECT; 1844 code = ICMP_REDIRECT_HOST; 1845 #ifdef DIAGNOSTIC 1846 if (ipprintfs) 1847 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1848 #endif 1849 } 1850 } 1851 1852 { 1853 struct m_hdr tag; 1854 1855 if (next_hop) { 1856 /* Pass IPFORWARD info if available */ 1857 1858 tag.mh_type = MT_TAG; 1859 tag.mh_flags = PACKET_TAG_IPFORWARD; 1860 tag.mh_data = (caddr_t)next_hop; 1861 tag.mh_next = m; 1862 m = (struct mbuf *)&tag; 1863 } 1864 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1865 IP_FORWARDING, 0, NULL); 1866 } 1867 if (error) 1868 ipstat.ips_cantforward++; 1869 else { 1870 ipstat.ips_forward++; 1871 if (type) 1872 ipstat.ips_redirectsent++; 1873 else { 1874 if (mcopy) { 1875 ipflow_create(&ipforward_rt, mcopy); 1876 m_freem(mcopy); 1877 } 1878 return; 1879 } 1880 } 1881 if (mcopy == NULL) 1882 return; 1883 destifp = NULL; 1884 1885 switch (error) { 1886 1887 case 0: /* forwarded, but need redirect */ 1888 /* type, code set above */ 1889 break; 1890 1891 case ENETUNREACH: /* shouldn't happen, checked above */ 1892 case EHOSTUNREACH: 1893 case ENETDOWN: 1894 case EHOSTDOWN: 1895 default: 1896 type = ICMP_UNREACH; 1897 code = ICMP_UNREACH_HOST; 1898 break; 1899 1900 case EMSGSIZE: 1901 type = ICMP_UNREACH; 1902 code = ICMP_UNREACH_NEEDFRAG; 1903 #ifdef IPSEC 1904 /* 1905 * If the packet is routed over IPsec tunnel, tell the 1906 * originator the tunnel MTU. 1907 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1908 * XXX quickhack!!! 1909 */ 1910 if (ipforward_rt.ro_rt) { 1911 struct secpolicy *sp = NULL; 1912 int ipsecerror; 1913 int ipsechdr; 1914 struct route *ro; 1915 1916 sp = ipsec4_getpolicybyaddr(mcopy, 1917 IPSEC_DIR_OUTBOUND, 1918 IP_FORWARDING, 1919 &ipsecerror); 1920 1921 if (sp == NULL) 1922 destifp = ipforward_rt.ro_rt->rt_ifp; 1923 else { 1924 /* count IPsec header size */ 1925 ipsechdr = ipsec4_hdrsiz(mcopy, 1926 IPSEC_DIR_OUTBOUND, 1927 NULL); 1928 1929 /* 1930 * find the correct route for outer IPv4 1931 * header, compute tunnel MTU. 1932 * 1933 * XXX BUG ALERT 1934 * The "dummyifp" code relies upon the fact 1935 * that icmp_error() touches only ifp->if_mtu. 1936 */ 1937 /*XXX*/ 1938 destifp = NULL; 1939 if (sp->req != NULL 1940 && sp->req->sav != NULL 1941 && sp->req->sav->sah != NULL) { 1942 ro = &sp->req->sav->sah->sa_route; 1943 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1944 dummyifp.if_mtu = 1945 ro->ro_rt->rt_ifp->if_mtu; 1946 dummyifp.if_mtu -= ipsechdr; 1947 destifp = &dummyifp; 1948 } 1949 } 1950 1951 key_freesp(sp); 1952 } 1953 } 1954 #elif FAST_IPSEC 1955 /* 1956 * If the packet is routed over IPsec tunnel, tell the 1957 * originator the tunnel MTU. 1958 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1959 * XXX quickhack!!! 1960 */ 1961 if (ipforward_rt.ro_rt) { 1962 struct secpolicy *sp = NULL; 1963 int ipsecerror; 1964 int ipsechdr; 1965 struct route *ro; 1966 1967 sp = ipsec_getpolicybyaddr(mcopy, 1968 IPSEC_DIR_OUTBOUND, 1969 IP_FORWARDING, 1970 &ipsecerror); 1971 1972 if (sp == NULL) 1973 destifp = ipforward_rt.ro_rt->rt_ifp; 1974 else { 1975 /* count IPsec header size */ 1976 ipsechdr = ipsec4_hdrsiz(mcopy, 1977 IPSEC_DIR_OUTBOUND, 1978 NULL); 1979 1980 /* 1981 * find the correct route for outer IPv4 1982 * header, compute tunnel MTU. 1983 * 1984 * XXX BUG ALERT 1985 * The "dummyifp" code relies upon the fact 1986 * that icmp_error() touches only ifp->if_mtu. 1987 */ 1988 /*XXX*/ 1989 destifp = NULL; 1990 if (sp->req != NULL 1991 && sp->req->sav != NULL 1992 && sp->req->sav->sah != NULL) { 1993 ro = &sp->req->sav->sah->sa_route; 1994 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1995 dummyifp.if_mtu = 1996 ro->ro_rt->rt_ifp->if_mtu; 1997 dummyifp.if_mtu -= ipsechdr; 1998 destifp = &dummyifp; 1999 } 2000 } 2001 2002 KEY_FREESP(&sp); 2003 } 2004 } 2005 #else /* !IPSEC && !FAST_IPSEC */ 2006 if (ipforward_rt.ro_rt) 2007 destifp = ipforward_rt.ro_rt->rt_ifp; 2008 #endif /*IPSEC*/ 2009 ipstat.ips_cantfrag++; 2010 break; 2011 2012 case ENOBUFS: 2013 /* 2014 * A router should not generate ICMP_SOURCEQUENCH as 2015 * required in RFC1812 Requirements for IP Version 4 Routers. 2016 * Source quench could be a big problem under DoS attacks, 2017 * or if the underlying interface is rate-limited. 2018 * Those who need source quench packets may re-enable them 2019 * via the net.inet.ip.sendsourcequench sysctl. 2020 */ 2021 if (ip_sendsourcequench == 0) { 2022 m_freem(mcopy); 2023 return; 2024 } else { 2025 type = ICMP_SOURCEQUENCH; 2026 code = 0; 2027 } 2028 break; 2029 2030 case EACCES: /* ipfw denied packet */ 2031 m_freem(mcopy); 2032 return; 2033 } 2034 icmp_error(mcopy, type, code, dest, destifp); 2035 } 2036 2037 void 2038 ip_savecontrol(inp, mp, ip, m) 2039 register struct inpcb *inp; 2040 register struct mbuf **mp; 2041 register struct ip *ip; 2042 register struct mbuf *m; 2043 { 2044 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2045 struct timeval tv; 2046 2047 microtime(&tv); 2048 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2049 SCM_TIMESTAMP, SOL_SOCKET); 2050 if (*mp) 2051 mp = &(*mp)->m_next; 2052 } 2053 if (inp->inp_flags & INP_RECVDSTADDR) { 2054 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2055 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2056 if (*mp) 2057 mp = &(*mp)->m_next; 2058 } 2059 if (inp->inp_flags & INP_RECVTTL) { 2060 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2061 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2062 if (*mp) 2063 mp = &(*mp)->m_next; 2064 } 2065 #ifdef notyet 2066 /* XXX 2067 * Moving these out of udp_input() made them even more broken 2068 * than they already were. 2069 */ 2070 /* options were tossed already */ 2071 if (inp->inp_flags & INP_RECVOPTS) { 2072 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2073 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2074 if (*mp) 2075 mp = &(*mp)->m_next; 2076 } 2077 /* ip_srcroute doesn't do what we want here, need to fix */ 2078 if (inp->inp_flags & INP_RECVRETOPTS) { 2079 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2080 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2081 if (*mp) 2082 mp = &(*mp)->m_next; 2083 } 2084 #endif 2085 if (inp->inp_flags & INP_RECVIF) { 2086 struct ifnet *ifp; 2087 struct sdlbuf { 2088 struct sockaddr_dl sdl; 2089 u_char pad[32]; 2090 } sdlbuf; 2091 struct sockaddr_dl *sdp; 2092 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2093 2094 if (((ifp = m->m_pkthdr.rcvif)) 2095 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2096 sdp = (struct sockaddr_dl *) 2097 (ifaddr_byindex(ifp->if_index)->ifa_addr); 2098 /* 2099 * Change our mind and don't try copy. 2100 */ 2101 if ((sdp->sdl_family != AF_LINK) 2102 || (sdp->sdl_len > sizeof(sdlbuf))) { 2103 goto makedummy; 2104 } 2105 bcopy(sdp, sdl2, sdp->sdl_len); 2106 } else { 2107 makedummy: 2108 sdl2->sdl_len 2109 = offsetof(struct sockaddr_dl, sdl_data[0]); 2110 sdl2->sdl_family = AF_LINK; 2111 sdl2->sdl_index = 0; 2112 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2113 } 2114 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2115 IP_RECVIF, IPPROTO_IP); 2116 if (*mp) 2117 mp = &(*mp)->m_next; 2118 } 2119 } 2120 2121 /* 2122 * XXX these routines are called from the upper part of the kernel. 2123 * They need to be locked when we remove Giant. 2124 * 2125 * They could also be moved to ip_mroute.c, since all the RSVP 2126 * handling is done there already. 2127 */ 2128 static int ip_rsvp_on; 2129 struct socket *ip_rsvpd; 2130 int 2131 ip_rsvp_init(struct socket *so) 2132 { 2133 if (so->so_type != SOCK_RAW || 2134 so->so_proto->pr_protocol != IPPROTO_RSVP) 2135 return EOPNOTSUPP; 2136 2137 if (ip_rsvpd != NULL) 2138 return EADDRINUSE; 2139 2140 ip_rsvpd = so; 2141 /* 2142 * This may seem silly, but we need to be sure we don't over-increment 2143 * the RSVP counter, in case something slips up. 2144 */ 2145 if (!ip_rsvp_on) { 2146 ip_rsvp_on = 1; 2147 rsvp_on++; 2148 } 2149 2150 return 0; 2151 } 2152 2153 int 2154 ip_rsvp_done(void) 2155 { 2156 ip_rsvpd = NULL; 2157 /* 2158 * This may seem silly, but we need to be sure we don't over-decrement 2159 * the RSVP counter, in case something slips up. 2160 */ 2161 if (ip_rsvp_on) { 2162 ip_rsvp_on = 0; 2163 rsvp_on--; 2164 } 2165 return 0; 2166 } 2167 2168 void 2169 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 2170 { 2171 if (rsvp_input_p) { /* call the real one if loaded */ 2172 rsvp_input_p(m, off); 2173 return; 2174 } 2175 2176 /* Can still get packets with rsvp_on = 0 if there is a local member 2177 * of the group to which the RSVP packet is addressed. But in this 2178 * case we want to throw the packet away. 2179 */ 2180 2181 if (!rsvp_on) { 2182 m_freem(m); 2183 return; 2184 } 2185 2186 if (ip_rsvpd != NULL) { 2187 rip_input(m, off); 2188 return; 2189 } 2190 /* Drop the packet */ 2191 m_freem(m); 2192 } 2193