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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: releng/5.1/sys/netinet/ip_input.c 114788 2003-05-06 20:34:04Z rwatson $ 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 433 434 /* 435 * IpHack's section. 436 * Right now when no processing on packet has done 437 * and it is still fresh out of network we do our black 438 * deals with it. 439 * - Firewall: deny/allow/divert 440 * - Xlate: translate packet's addr/port (NAT). 441 * - Pipe: pass pkt through dummynet. 442 * - Wrap: fake packet's addr/port <unimpl.> 443 * - Encapsulate: put it in another IP and send out. <unimp.> 444 */ 445 446 iphack: 447 448 #ifdef PFIL_HOOKS 449 /* 450 * Run through list of hooks for input packets. If there are any 451 * filters which require that additional packets in the flow are 452 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 453 * Note that filters must _never_ set this flag, as another filter 454 * in the list may have previously cleared it. 455 */ 456 m0 = m; 457 pfh = pfil_hook_get(PFIL_IN, &inetsw[ip_protox[IPPROTO_IP]].pr_pfh); 458 for (; pfh; pfh = TAILQ_NEXT(pfh, pfil_link)) 459 if (pfh->pfil_func) { 460 rv = pfh->pfil_func(ip, hlen, 461 m->m_pkthdr.rcvif, 0, &m0); 462 if (rv) 463 return; 464 m = m0; 465 if (m == NULL) 466 return; 467 ip = mtod(m, struct ip *); 468 } 469 #endif /* PFIL_HOOKS */ 470 471 if (fw_enable && IPFW_LOADED) { 472 /* 473 * If we've been forwarded from the output side, then 474 * skip the firewall a second time 475 */ 476 if (args.next_hop) 477 goto ours; 478 479 args.m = m; 480 i = ip_fw_chk_ptr(&args); 481 m = args.m; 482 483 if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 484 if (m) 485 m_freem(m); 486 return; 487 } 488 ip = mtod(m, struct ip *); /* just in case m changed */ 489 if (i == 0 && args.next_hop == NULL) /* common case */ 490 goto pass; 491 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) { 492 /* Send packet to the appropriate pipe */ 493 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 494 return; 495 } 496 #ifdef IPDIVERT 497 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 498 /* Divert or tee packet */ 499 divert_info = i; 500 goto ours; 501 } 502 #endif 503 if (i == 0 && args.next_hop != NULL) 504 goto pass; 505 /* 506 * if we get here, the packet must be dropped 507 */ 508 m_freem(m); 509 return; 510 } 511 pass: 512 513 /* 514 * Process options and, if not destined for us, 515 * ship it on. ip_dooptions returns 1 when an 516 * error was detected (causing an icmp message 517 * to be sent and the original packet to be freed). 518 */ 519 ip_nhops = 0; /* for source routed packets */ 520 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, args.next_hop)) 521 return; 522 523 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 524 * matter if it is destined to another node, or whether it is 525 * a multicast one, RSVP wants it! and prevents it from being forwarded 526 * anywhere else. Also checks if the rsvp daemon is running before 527 * grabbing the packet. 528 */ 529 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 530 goto ours; 531 532 /* 533 * Check our list of addresses, to see if the packet is for us. 534 * If we don't have any addresses, assume any unicast packet 535 * we receive might be for us (and let the upper layers deal 536 * with it). 537 */ 538 if (TAILQ_EMPTY(&in_ifaddrhead) && 539 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 540 goto ours; 541 542 /* 543 * Cache the destination address of the packet; this may be 544 * changed by use of 'ipfw fwd'. 545 */ 546 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 547 548 /* 549 * Enable a consistency check between the destination address 550 * and the arrival interface for a unicast packet (the RFC 1122 551 * strong ES model) if IP forwarding is disabled and the packet 552 * is not locally generated and the packet is not subject to 553 * 'ipfw fwd'. 554 * 555 * XXX - Checking also should be disabled if the destination 556 * address is ipnat'ed to a different interface. 557 * 558 * XXX - Checking is incompatible with IP aliases added 559 * to the loopback interface instead of the interface where 560 * the packets are received. 561 */ 562 checkif = ip_checkinterface && (ipforwarding == 0) && 563 m->m_pkthdr.rcvif != NULL && 564 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 565 (args.next_hop == NULL); 566 567 /* 568 * Check for exact addresses in the hash bucket. 569 */ 570 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 571 /* 572 * If the address matches, verify that the packet 573 * arrived via the correct interface if checking is 574 * enabled. 575 */ 576 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 577 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 578 goto ours; 579 } 580 /* 581 * Check for broadcast addresses. 582 * 583 * Only accept broadcast packets that arrive via the matching 584 * interface. Reception of forwarded directed broadcasts would 585 * be handled via ip_forward() and ether_output() with the loopback 586 * into the stack for SIMPLEX interfaces handled by ether_output(). 587 */ 588 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 589 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 590 if (ifa->ifa_addr->sa_family != AF_INET) 591 continue; 592 ia = ifatoia(ifa); 593 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 594 pkt_dst.s_addr) 595 goto ours; 596 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 597 goto ours; 598 #ifdef BOOTP_COMPAT 599 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 600 goto ours; 601 #endif 602 } 603 } 604 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 605 struct in_multi *inm; 606 if (ip_mrouter) { 607 /* 608 * If we are acting as a multicast router, all 609 * incoming multicast packets are passed to the 610 * kernel-level multicast forwarding function. 611 * The packet is returned (relatively) intact; if 612 * ip_mforward() returns a non-zero value, the packet 613 * must be discarded, else it may be accepted below. 614 */ 615 if (ip_mforward && 616 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 617 ipstat.ips_cantforward++; 618 m_freem(m); 619 return; 620 } 621 622 /* 623 * The process-level routing daemon needs to receive 624 * all multicast IGMP packets, whether or not this 625 * host belongs to their destination groups. 626 */ 627 if (ip->ip_p == IPPROTO_IGMP) 628 goto ours; 629 ipstat.ips_forward++; 630 } 631 /* 632 * See if we belong to the destination multicast group on the 633 * arrival interface. 634 */ 635 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 636 if (inm == NULL) { 637 ipstat.ips_notmember++; 638 m_freem(m); 639 return; 640 } 641 goto ours; 642 } 643 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 644 goto ours; 645 if (ip->ip_dst.s_addr == INADDR_ANY) 646 goto ours; 647 648 /* 649 * FAITH(Firewall Aided Internet Translator) 650 */ 651 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 652 if (ip_keepfaith) { 653 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 654 goto ours; 655 } 656 m_freem(m); 657 return; 658 } 659 660 /* 661 * Not for us; forward if possible and desirable. 662 */ 663 if (ipforwarding == 0) { 664 ipstat.ips_cantforward++; 665 m_freem(m); 666 } else { 667 #ifdef IPSEC 668 /* 669 * Enforce inbound IPsec SPD. 670 */ 671 if (ipsec4_in_reject(m, NULL)) { 672 ipsecstat.in_polvio++; 673 goto bad; 674 } 675 #endif /* IPSEC */ 676 #ifdef FAST_IPSEC 677 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 678 s = splnet(); 679 if (mtag != NULL) { 680 tdbi = (struct tdb_ident *)(mtag + 1); 681 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 682 } else { 683 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 684 IP_FORWARDING, &error); 685 } 686 if (sp == NULL) { /* NB: can happen if error */ 687 splx(s); 688 /*XXX error stat???*/ 689 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 690 goto bad; 691 } 692 693 /* 694 * Check security policy against packet attributes. 695 */ 696 error = ipsec_in_reject(sp, m); 697 KEY_FREESP(&sp); 698 splx(s); 699 if (error) { 700 ipstat.ips_cantforward++; 701 goto bad; 702 } 703 #endif /* FAST_IPSEC */ 704 ip_forward(m, 0, args.next_hop); 705 } 706 return; 707 708 ours: 709 #ifdef IPSTEALTH 710 /* 711 * IPSTEALTH: Process non-routing options only 712 * if the packet is destined for us. 713 */ 714 if (ipstealth && hlen > sizeof (struct ip) && 715 ip_dooptions(m, 1, args.next_hop)) 716 return; 717 #endif /* IPSTEALTH */ 718 719 /* Count the packet in the ip address stats */ 720 if (ia != NULL) { 721 ia->ia_ifa.if_ipackets++; 722 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 723 } 724 725 /* 726 * If offset or IP_MF are set, must reassemble. 727 * Otherwise, nothing need be done. 728 * (We could look in the reassembly queue to see 729 * if the packet was previously fragmented, 730 * but it's not worth the time; just let them time out.) 731 */ 732 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 733 734 /* If maxnipq is 0, never accept fragments. */ 735 if (maxnipq == 0) { 736 ipstat.ips_fragments++; 737 ipstat.ips_fragdropped++; 738 goto bad; 739 } 740 741 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 742 /* 743 * Look for queue of fragments 744 * of this datagram. 745 */ 746 TAILQ_FOREACH(fp, &ipq[sum], ipq_list) 747 if (ip->ip_id == fp->ipq_id && 748 ip->ip_src.s_addr == fp->ipq_src.s_addr && 749 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 750 #ifdef MAC 751 mac_fragment_match(m, fp) && 752 #endif 753 ip->ip_p == fp->ipq_p) 754 goto found; 755 756 fp = 0; 757 758 /* 759 * Enforce upper bound on number of fragmented packets 760 * for which we attempt reassembly; 761 * If maxnipq is -1, accept all fragments without limitation. 762 */ 763 if ((nipq > maxnipq) && (maxnipq > 0)) { 764 /* 765 * drop something from the tail of the current queue 766 * before proceeding further 767 */ 768 struct ipq *q = TAILQ_LAST(&ipq[sum], ipqhead); 769 if (q == NULL) { /* gak */ 770 for (i = 0; i < IPREASS_NHASH; i++) { 771 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 772 if (r) { 773 ipstat.ips_fragtimeout += r->ipq_nfrags; 774 ip_freef(&ipq[i], r); 775 break; 776 } 777 } 778 } else { 779 ipstat.ips_fragtimeout += q->ipq_nfrags; 780 ip_freef(&ipq[sum], q); 781 } 782 } 783 found: 784 /* 785 * Adjust ip_len to not reflect header, 786 * convert offset of this to bytes. 787 */ 788 ip->ip_len -= hlen; 789 if (ip->ip_off & IP_MF) { 790 /* 791 * Make sure that fragments have a data length 792 * that's a non-zero multiple of 8 bytes. 793 */ 794 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 795 ipstat.ips_toosmall++; /* XXX */ 796 goto bad; 797 } 798 m->m_flags |= M_FRAG; 799 } else 800 m->m_flags &= ~M_FRAG; 801 ip->ip_off <<= 3; 802 803 /* 804 * Attempt reassembly; if it succeeds, proceed. 805 * ip_reass() will return a different mbuf, and update 806 * the divert info in divert_info and args.divert_rule. 807 */ 808 ipstat.ips_fragments++; 809 m->m_pkthdr.header = ip; 810 m = ip_reass(m, 811 &ipq[sum], fp, &divert_info, &args.divert_rule); 812 if (m == 0) 813 return; 814 ipstat.ips_reassembled++; 815 ip = mtod(m, struct ip *); 816 /* Get the header length of the reassembled packet */ 817 hlen = ip->ip_hl << 2; 818 #ifdef IPDIVERT 819 /* Restore original checksum before diverting packet */ 820 if (divert_info != 0) { 821 ip->ip_len += hlen; 822 ip->ip_len = htons(ip->ip_len); 823 ip->ip_off = htons(ip->ip_off); 824 ip->ip_sum = 0; 825 if (hlen == sizeof(struct ip)) 826 ip->ip_sum = in_cksum_hdr(ip); 827 else 828 ip->ip_sum = in_cksum(m, hlen); 829 ip->ip_off = ntohs(ip->ip_off); 830 ip->ip_len = ntohs(ip->ip_len); 831 ip->ip_len -= hlen; 832 } 833 #endif 834 } else 835 ip->ip_len -= hlen; 836 837 #ifdef IPDIVERT 838 /* 839 * Divert or tee packet to the divert protocol if required. 840 */ 841 if (divert_info != 0) { 842 struct mbuf *clone = NULL; 843 844 /* Clone packet if we're doing a 'tee' */ 845 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 846 clone = m_dup(m, M_DONTWAIT); 847 848 /* Restore packet header fields to original values */ 849 ip->ip_len += hlen; 850 ip->ip_len = htons(ip->ip_len); 851 ip->ip_off = htons(ip->ip_off); 852 853 /* Deliver packet to divert input routine */ 854 divert_packet(m, 1, divert_info & 0xffff, args.divert_rule); 855 ipstat.ips_delivered++; 856 857 /* If 'tee', continue with original packet */ 858 if (clone == NULL) 859 return; 860 m = clone; 861 ip = mtod(m, struct ip *); 862 ip->ip_len += hlen; 863 /* 864 * Jump backwards to complete processing of the 865 * packet. But first clear divert_info to avoid 866 * entering this block again. 867 * We do not need to clear args.divert_rule 868 * or args.next_hop as they will not be used. 869 */ 870 divert_info = 0; 871 goto pass; 872 } 873 #endif 874 875 #ifdef IPSEC 876 /* 877 * enforce IPsec policy checking if we are seeing last header. 878 * note that we do not visit this with protocols with pcb layer 879 * code - like udp/tcp/raw ip. 880 */ 881 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 882 ipsec4_in_reject(m, NULL)) { 883 ipsecstat.in_polvio++; 884 goto bad; 885 } 886 #endif 887 #if FAST_IPSEC 888 /* 889 * enforce IPsec policy checking if we are seeing last header. 890 * note that we do not visit this with protocols with pcb layer 891 * code - like udp/tcp/raw ip. 892 */ 893 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 894 /* 895 * Check if the packet has already had IPsec processing 896 * done. If so, then just pass it along. This tag gets 897 * set during AH, ESP, etc. input handling, before the 898 * packet is returned to the ip input queue for delivery. 899 */ 900 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 901 s = splnet(); 902 if (mtag != NULL) { 903 tdbi = (struct tdb_ident *)(mtag + 1); 904 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 905 } else { 906 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 907 IP_FORWARDING, &error); 908 } 909 if (sp != NULL) { 910 /* 911 * Check security policy against packet attributes. 912 */ 913 error = ipsec_in_reject(sp, m); 914 KEY_FREESP(&sp); 915 } else { 916 /* XXX error stat??? */ 917 error = EINVAL; 918 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 919 goto bad; 920 } 921 splx(s); 922 if (error) 923 goto bad; 924 } 925 #endif /* FAST_IPSEC */ 926 927 /* 928 * Switch out to protocol's input routine. 929 */ 930 ipstat.ips_delivered++; 931 if (args.next_hop && ip->ip_p == IPPROTO_TCP) { 932 /* TCP needs IPFORWARD info if available */ 933 struct m_hdr tag; 934 935 tag.mh_type = MT_TAG; 936 tag.mh_flags = PACKET_TAG_IPFORWARD; 937 tag.mh_data = (caddr_t)args.next_hop; 938 tag.mh_next = m; 939 940 (*inetsw[ip_protox[ip->ip_p]].pr_input)( 941 (struct mbuf *)&tag, hlen); 942 } else 943 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 944 return; 945 bad: 946 m_freem(m); 947 } 948 949 /* 950 * Take incoming datagram fragment and try to reassemble it into 951 * whole datagram. If a chain for reassembly of this datagram already 952 * exists, then it is given as fp; otherwise have to make a chain. 953 * 954 * When IPDIVERT enabled, keep additional state with each packet that 955 * tells us if we need to divert or tee the packet we're building. 956 * In particular, *divinfo includes the port and TEE flag, 957 * *divert_rule is the number of the matching rule. 958 */ 959 960 static struct mbuf * 961 ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp, 962 u_int32_t *divinfo, u_int16_t *divert_rule) 963 { 964 struct ip *ip = mtod(m, struct ip *); 965 register struct mbuf *p, *q, *nq; 966 struct mbuf *t; 967 int hlen = ip->ip_hl << 2; 968 int i, next; 969 970 /* 971 * Presence of header sizes in mbufs 972 * would confuse code below. 973 */ 974 m->m_data += hlen; 975 m->m_len -= hlen; 976 977 /* 978 * If first fragment to arrive, create a reassembly queue. 979 */ 980 if (fp == 0) { 981 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 982 goto dropfrag; 983 fp = mtod(t, struct ipq *); 984 #ifdef MAC 985 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 986 m_free(t); 987 goto dropfrag; 988 } 989 mac_create_ipq(m, fp); 990 #endif 991 TAILQ_INSERT_HEAD(head, fp, ipq_list); 992 nipq++; 993 fp->ipq_nfrags = 1; 994 fp->ipq_ttl = IPFRAGTTL; 995 fp->ipq_p = ip->ip_p; 996 fp->ipq_id = ip->ip_id; 997 fp->ipq_src = ip->ip_src; 998 fp->ipq_dst = ip->ip_dst; 999 fp->ipq_frags = m; 1000 m->m_nextpkt = NULL; 1001 #ifdef IPDIVERT 1002 fp->ipq_div_info = 0; 1003 fp->ipq_div_cookie = 0; 1004 #endif 1005 goto inserted; 1006 } else { 1007 fp->ipq_nfrags++; 1008 #ifdef MAC 1009 mac_update_ipq(m, fp); 1010 #endif 1011 } 1012 1013 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1014 1015 /* 1016 * Find a segment which begins after this one does. 1017 */ 1018 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1019 if (GETIP(q)->ip_off > ip->ip_off) 1020 break; 1021 1022 /* 1023 * If there is a preceding segment, it may provide some of 1024 * our data already. If so, drop the data from the incoming 1025 * segment. If it provides all of our data, drop us, otherwise 1026 * stick new segment in the proper place. 1027 * 1028 * If some of the data is dropped from the the preceding 1029 * segment, then it's checksum is invalidated. 1030 */ 1031 if (p) { 1032 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1033 if (i > 0) { 1034 if (i >= ip->ip_len) 1035 goto dropfrag; 1036 m_adj(m, i); 1037 m->m_pkthdr.csum_flags = 0; 1038 ip->ip_off += i; 1039 ip->ip_len -= i; 1040 } 1041 m->m_nextpkt = p->m_nextpkt; 1042 p->m_nextpkt = m; 1043 } else { 1044 m->m_nextpkt = fp->ipq_frags; 1045 fp->ipq_frags = m; 1046 } 1047 1048 /* 1049 * While we overlap succeeding segments trim them or, 1050 * if they are completely covered, dequeue them. 1051 */ 1052 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1053 q = nq) { 1054 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1055 if (i < GETIP(q)->ip_len) { 1056 GETIP(q)->ip_len -= i; 1057 GETIP(q)->ip_off += i; 1058 m_adj(q, i); 1059 q->m_pkthdr.csum_flags = 0; 1060 break; 1061 } 1062 nq = q->m_nextpkt; 1063 m->m_nextpkt = nq; 1064 ipstat.ips_fragdropped++; 1065 fp->ipq_nfrags--; 1066 m_freem(q); 1067 } 1068 1069 inserted: 1070 1071 #ifdef IPDIVERT 1072 /* 1073 * Transfer firewall instructions to the fragment structure. 1074 * Only trust info in the fragment at offset 0. 1075 */ 1076 if (ip->ip_off == 0) { 1077 fp->ipq_div_info = *divinfo; 1078 fp->ipq_div_cookie = *divert_rule; 1079 } 1080 *divinfo = 0; 1081 *divert_rule = 0; 1082 #endif 1083 1084 /* 1085 * Check for complete reassembly and perform frag per packet 1086 * limiting. 1087 * 1088 * Frag limiting is performed here so that the nth frag has 1089 * a chance to complete the packet before we drop the packet. 1090 * As a result, n+1 frags are actually allowed per packet, but 1091 * only n will ever be stored. (n = maxfragsperpacket.) 1092 * 1093 */ 1094 next = 0; 1095 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1096 if (GETIP(q)->ip_off != next) { 1097 if (fp->ipq_nfrags > maxfragsperpacket) { 1098 ipstat.ips_fragdropped += fp->ipq_nfrags; 1099 ip_freef(head, fp); 1100 } 1101 return (0); 1102 } 1103 next += GETIP(q)->ip_len; 1104 } 1105 /* Make sure the last packet didn't have the IP_MF flag */ 1106 if (p->m_flags & M_FRAG) { 1107 if (fp->ipq_nfrags > maxfragsperpacket) { 1108 ipstat.ips_fragdropped += fp->ipq_nfrags; 1109 ip_freef(head, fp); 1110 } 1111 return (0); 1112 } 1113 1114 /* 1115 * Reassembly is complete. Make sure the packet is a sane size. 1116 */ 1117 q = fp->ipq_frags; 1118 ip = GETIP(q); 1119 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1120 ipstat.ips_toolong++; 1121 ipstat.ips_fragdropped += fp->ipq_nfrags; 1122 ip_freef(head, fp); 1123 return (0); 1124 } 1125 1126 /* 1127 * Concatenate fragments. 1128 */ 1129 m = q; 1130 t = m->m_next; 1131 m->m_next = 0; 1132 m_cat(m, t); 1133 nq = q->m_nextpkt; 1134 q->m_nextpkt = 0; 1135 for (q = nq; q != NULL; q = nq) { 1136 nq = q->m_nextpkt; 1137 q->m_nextpkt = NULL; 1138 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1139 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1140 m_cat(m, q); 1141 } 1142 #ifdef MAC 1143 mac_create_datagram_from_ipq(fp, m); 1144 mac_destroy_ipq(fp); 1145 #endif 1146 1147 #ifdef IPDIVERT 1148 /* 1149 * Extract firewall instructions from the fragment structure. 1150 */ 1151 *divinfo = fp->ipq_div_info; 1152 *divert_rule = fp->ipq_div_cookie; 1153 #endif 1154 1155 /* 1156 * Create header for new ip packet by 1157 * modifying header of first packet; 1158 * dequeue and discard fragment reassembly header. 1159 * Make header visible. 1160 */ 1161 ip->ip_len = next; 1162 ip->ip_src = fp->ipq_src; 1163 ip->ip_dst = fp->ipq_dst; 1164 TAILQ_REMOVE(head, fp, ipq_list); 1165 nipq--; 1166 (void) m_free(dtom(fp)); 1167 m->m_len += (ip->ip_hl << 2); 1168 m->m_data -= (ip->ip_hl << 2); 1169 /* some debugging cruft by sklower, below, will go away soon */ 1170 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1171 m_fixhdr(m); 1172 return (m); 1173 1174 dropfrag: 1175 #ifdef IPDIVERT 1176 *divinfo = 0; 1177 *divert_rule = 0; 1178 #endif 1179 ipstat.ips_fragdropped++; 1180 if (fp != 0) 1181 fp->ipq_nfrags--; 1182 m_freem(m); 1183 return (0); 1184 1185 #undef GETIP 1186 } 1187 1188 /* 1189 * Free a fragment reassembly header and all 1190 * associated datagrams. 1191 */ 1192 static void 1193 ip_freef(fhp, fp) 1194 struct ipqhead *fhp; 1195 struct ipq *fp; 1196 { 1197 register struct mbuf *q; 1198 1199 while (fp->ipq_frags) { 1200 q = fp->ipq_frags; 1201 fp->ipq_frags = q->m_nextpkt; 1202 m_freem(q); 1203 } 1204 TAILQ_REMOVE(fhp, fp, ipq_list); 1205 (void) m_free(dtom(fp)); 1206 nipq--; 1207 } 1208 1209 /* 1210 * IP timer processing; 1211 * if a timer expires on a reassembly 1212 * queue, discard it. 1213 */ 1214 void 1215 ip_slowtimo() 1216 { 1217 register struct ipq *fp; 1218 int s = splnet(); 1219 int i; 1220 1221 for (i = 0; i < IPREASS_NHASH; i++) { 1222 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1223 struct ipq *fpp; 1224 1225 fpp = fp; 1226 fp = TAILQ_NEXT(fp, ipq_list); 1227 if(--fpp->ipq_ttl == 0) { 1228 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1229 ip_freef(&ipq[i], fpp); 1230 } 1231 } 1232 } 1233 /* 1234 * If we are over the maximum number of fragments 1235 * (due to the limit being lowered), drain off 1236 * enough to get down to the new limit. 1237 */ 1238 if (maxnipq >= 0 && nipq > maxnipq) { 1239 for (i = 0; i < IPREASS_NHASH; i++) { 1240 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1241 ipstat.ips_fragdropped += 1242 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1243 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1244 } 1245 } 1246 } 1247 ipflow_slowtimo(); 1248 splx(s); 1249 } 1250 1251 /* 1252 * Drain off all datagram fragments. 1253 */ 1254 void 1255 ip_drain() 1256 { 1257 int i; 1258 1259 for (i = 0; i < IPREASS_NHASH; i++) { 1260 while(!TAILQ_EMPTY(&ipq[i])) { 1261 ipstat.ips_fragdropped += 1262 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1263 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1264 } 1265 } 1266 in_rtqdrain(); 1267 } 1268 1269 /* 1270 * Do option processing on a datagram, 1271 * possibly discarding it if bad options are encountered, 1272 * or forwarding it if source-routed. 1273 * The pass argument is used when operating in the IPSTEALTH 1274 * mode to tell what options to process: 1275 * [LS]SRR (pass 0) or the others (pass 1). 1276 * The reason for as many as two passes is that when doing IPSTEALTH, 1277 * non-routing options should be processed only if the packet is for us. 1278 * Returns 1 if packet has been forwarded/freed, 1279 * 0 if the packet should be processed further. 1280 */ 1281 static int 1282 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1283 { 1284 struct ip *ip = mtod(m, struct ip *); 1285 u_char *cp; 1286 struct in_ifaddr *ia; 1287 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1288 struct in_addr *sin, dst; 1289 n_time ntime; 1290 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 1291 1292 dst = ip->ip_dst; 1293 cp = (u_char *)(ip + 1); 1294 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1295 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1296 opt = cp[IPOPT_OPTVAL]; 1297 if (opt == IPOPT_EOL) 1298 break; 1299 if (opt == IPOPT_NOP) 1300 optlen = 1; 1301 else { 1302 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1303 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1304 goto bad; 1305 } 1306 optlen = cp[IPOPT_OLEN]; 1307 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1308 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1309 goto bad; 1310 } 1311 } 1312 switch (opt) { 1313 1314 default: 1315 break; 1316 1317 /* 1318 * Source routing with record. 1319 * Find interface with current destination address. 1320 * If none on this machine then drop if strictly routed, 1321 * or do nothing if loosely routed. 1322 * Record interface address and bring up next address 1323 * component. If strictly routed make sure next 1324 * address is on directly accessible net. 1325 */ 1326 case IPOPT_LSRR: 1327 case IPOPT_SSRR: 1328 #ifdef IPSTEALTH 1329 if (ipstealth && pass > 0) 1330 break; 1331 #endif 1332 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1333 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1334 goto bad; 1335 } 1336 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1337 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1338 goto bad; 1339 } 1340 ipaddr.sin_addr = ip->ip_dst; 1341 ia = (struct in_ifaddr *) 1342 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1343 if (ia == 0) { 1344 if (opt == IPOPT_SSRR) { 1345 type = ICMP_UNREACH; 1346 code = ICMP_UNREACH_SRCFAIL; 1347 goto bad; 1348 } 1349 if (!ip_dosourceroute) 1350 goto nosourcerouting; 1351 /* 1352 * Loose routing, and not at next destination 1353 * yet; nothing to do except forward. 1354 */ 1355 break; 1356 } 1357 off--; /* 0 origin */ 1358 if (off > optlen - (int)sizeof(struct in_addr)) { 1359 /* 1360 * End of source route. Should be for us. 1361 */ 1362 if (!ip_acceptsourceroute) 1363 goto nosourcerouting; 1364 save_rte(cp, ip->ip_src); 1365 break; 1366 } 1367 #ifdef IPSTEALTH 1368 if (ipstealth) 1369 goto dropit; 1370 #endif 1371 if (!ip_dosourceroute) { 1372 if (ipforwarding) { 1373 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1374 /* 1375 * Acting as a router, so generate ICMP 1376 */ 1377 nosourcerouting: 1378 strcpy(buf, inet_ntoa(ip->ip_dst)); 1379 log(LOG_WARNING, 1380 "attempted source route from %s to %s\n", 1381 inet_ntoa(ip->ip_src), buf); 1382 type = ICMP_UNREACH; 1383 code = ICMP_UNREACH_SRCFAIL; 1384 goto bad; 1385 } else { 1386 /* 1387 * Not acting as a router, so silently drop. 1388 */ 1389 #ifdef IPSTEALTH 1390 dropit: 1391 #endif 1392 ipstat.ips_cantforward++; 1393 m_freem(m); 1394 return (1); 1395 } 1396 } 1397 1398 /* 1399 * locate outgoing interface 1400 */ 1401 (void)memcpy(&ipaddr.sin_addr, cp + off, 1402 sizeof(ipaddr.sin_addr)); 1403 1404 if (opt == IPOPT_SSRR) { 1405 #define INA struct in_ifaddr * 1406 #define SA struct sockaddr * 1407 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1408 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1409 } else 1410 ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt); 1411 if (ia == 0) { 1412 type = ICMP_UNREACH; 1413 code = ICMP_UNREACH_SRCFAIL; 1414 goto bad; 1415 } 1416 ip->ip_dst = ipaddr.sin_addr; 1417 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1418 sizeof(struct in_addr)); 1419 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1420 /* 1421 * Let ip_intr's mcast routing check handle mcast pkts 1422 */ 1423 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1424 break; 1425 1426 case IPOPT_RR: 1427 #ifdef IPSTEALTH 1428 if (ipstealth && pass == 0) 1429 break; 1430 #endif 1431 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1432 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1433 goto bad; 1434 } 1435 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1436 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1437 goto bad; 1438 } 1439 /* 1440 * If no space remains, ignore. 1441 */ 1442 off--; /* 0 origin */ 1443 if (off > optlen - (int)sizeof(struct in_addr)) 1444 break; 1445 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1446 sizeof(ipaddr.sin_addr)); 1447 /* 1448 * locate outgoing interface; if we're the destination, 1449 * use the incoming interface (should be same). 1450 */ 1451 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1452 (ia = ip_rtaddr(ipaddr.sin_addr, 1453 &ipforward_rt)) == 0) { 1454 type = ICMP_UNREACH; 1455 code = ICMP_UNREACH_HOST; 1456 goto bad; 1457 } 1458 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1459 sizeof(struct in_addr)); 1460 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1461 break; 1462 1463 case IPOPT_TS: 1464 #ifdef IPSTEALTH 1465 if (ipstealth && pass == 0) 1466 break; 1467 #endif 1468 code = cp - (u_char *)ip; 1469 if (optlen < 4 || optlen > 40) { 1470 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1471 goto bad; 1472 } 1473 if ((off = cp[IPOPT_OFFSET]) < 5) { 1474 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1475 goto bad; 1476 } 1477 if (off > optlen - (int)sizeof(int32_t)) { 1478 cp[IPOPT_OFFSET + 1] += (1 << 4); 1479 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1480 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1481 goto bad; 1482 } 1483 break; 1484 } 1485 off--; /* 0 origin */ 1486 sin = (struct in_addr *)(cp + off); 1487 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1488 1489 case IPOPT_TS_TSONLY: 1490 break; 1491 1492 case IPOPT_TS_TSANDADDR: 1493 if (off + sizeof(n_time) + 1494 sizeof(struct in_addr) > optlen) { 1495 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1496 goto bad; 1497 } 1498 ipaddr.sin_addr = dst; 1499 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1500 m->m_pkthdr.rcvif); 1501 if (ia == 0) 1502 continue; 1503 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1504 sizeof(struct in_addr)); 1505 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1506 off += sizeof(struct in_addr); 1507 break; 1508 1509 case IPOPT_TS_PRESPEC: 1510 if (off + sizeof(n_time) + 1511 sizeof(struct in_addr) > optlen) { 1512 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1513 goto bad; 1514 } 1515 (void)memcpy(&ipaddr.sin_addr, sin, 1516 sizeof(struct in_addr)); 1517 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1518 continue; 1519 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1520 off += sizeof(struct in_addr); 1521 break; 1522 1523 default: 1524 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1525 goto bad; 1526 } 1527 ntime = iptime(); 1528 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1529 cp[IPOPT_OFFSET] += sizeof(n_time); 1530 } 1531 } 1532 if (forward && ipforwarding) { 1533 ip_forward(m, 1, next_hop); 1534 return (1); 1535 } 1536 return (0); 1537 bad: 1538 icmp_error(m, type, code, 0, 0); 1539 ipstat.ips_badoptions++; 1540 return (1); 1541 } 1542 1543 /* 1544 * Given address of next destination (final or next hop), 1545 * return internet address info of interface to be used to get there. 1546 */ 1547 struct in_ifaddr * 1548 ip_rtaddr(dst, rt) 1549 struct in_addr dst; 1550 struct route *rt; 1551 { 1552 register struct sockaddr_in *sin; 1553 1554 sin = (struct sockaddr_in *)&rt->ro_dst; 1555 1556 if (rt->ro_rt == 0 || 1557 !(rt->ro_rt->rt_flags & RTF_UP) || 1558 dst.s_addr != sin->sin_addr.s_addr) { 1559 if (rt->ro_rt) { 1560 RTFREE(rt->ro_rt); 1561 rt->ro_rt = 0; 1562 } 1563 sin->sin_family = AF_INET; 1564 sin->sin_len = sizeof(*sin); 1565 sin->sin_addr = dst; 1566 1567 rtalloc_ign(rt, RTF_PRCLONING); 1568 } 1569 if (rt->ro_rt == 0) 1570 return ((struct in_ifaddr *)0); 1571 return (ifatoia(rt->ro_rt->rt_ifa)); 1572 } 1573 1574 /* 1575 * Save incoming source route for use in replies, 1576 * to be picked up later by ip_srcroute if the receiver is interested. 1577 */ 1578 static void 1579 save_rte(option, dst) 1580 u_char *option; 1581 struct in_addr dst; 1582 { 1583 unsigned olen; 1584 1585 olen = option[IPOPT_OLEN]; 1586 #ifdef DIAGNOSTIC 1587 if (ipprintfs) 1588 printf("save_rte: olen %d\n", olen); 1589 #endif 1590 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1591 return; 1592 bcopy(option, ip_srcrt.srcopt, olen); 1593 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1594 ip_srcrt.dst = dst; 1595 } 1596 1597 /* 1598 * Retrieve incoming source route for use in replies, 1599 * in the same form used by setsockopt. 1600 * The first hop is placed before the options, will be removed later. 1601 */ 1602 struct mbuf * 1603 ip_srcroute() 1604 { 1605 register struct in_addr *p, *q; 1606 register struct mbuf *m; 1607 1608 if (ip_nhops == 0) 1609 return ((struct mbuf *)0); 1610 m = m_get(M_DONTWAIT, MT_HEADER); 1611 if (m == 0) 1612 return ((struct mbuf *)0); 1613 1614 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1615 1616 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1617 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1618 OPTSIZ; 1619 #ifdef DIAGNOSTIC 1620 if (ipprintfs) 1621 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1622 #endif 1623 1624 /* 1625 * First save first hop for return route 1626 */ 1627 p = &ip_srcrt.route[ip_nhops - 1]; 1628 *(mtod(m, struct in_addr *)) = *p--; 1629 #ifdef DIAGNOSTIC 1630 if (ipprintfs) 1631 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1632 #endif 1633 1634 /* 1635 * Copy option fields and padding (nop) to mbuf. 1636 */ 1637 ip_srcrt.nop = IPOPT_NOP; 1638 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1639 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1640 &ip_srcrt.nop, OPTSIZ); 1641 q = (struct in_addr *)(mtod(m, caddr_t) + 1642 sizeof(struct in_addr) + OPTSIZ); 1643 #undef OPTSIZ 1644 /* 1645 * Record return path as an IP source route, 1646 * reversing the path (pointers are now aligned). 1647 */ 1648 while (p >= ip_srcrt.route) { 1649 #ifdef DIAGNOSTIC 1650 if (ipprintfs) 1651 printf(" %lx", (u_long)ntohl(q->s_addr)); 1652 #endif 1653 *q++ = *p--; 1654 } 1655 /* 1656 * Last hop goes to final destination. 1657 */ 1658 *q = ip_srcrt.dst; 1659 #ifdef DIAGNOSTIC 1660 if (ipprintfs) 1661 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1662 #endif 1663 return (m); 1664 } 1665 1666 /* 1667 * Strip out IP options, at higher 1668 * level protocol in the kernel. 1669 * Second argument is buffer to which options 1670 * will be moved, and return value is their length. 1671 * XXX should be deleted; last arg currently ignored. 1672 */ 1673 void 1674 ip_stripoptions(m, mopt) 1675 register struct mbuf *m; 1676 struct mbuf *mopt; 1677 { 1678 register int i; 1679 struct ip *ip = mtod(m, struct ip *); 1680 register caddr_t opts; 1681 int olen; 1682 1683 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1684 opts = (caddr_t)(ip + 1); 1685 i = m->m_len - (sizeof (struct ip) + olen); 1686 bcopy(opts + olen, opts, (unsigned)i); 1687 m->m_len -= olen; 1688 if (m->m_flags & M_PKTHDR) 1689 m->m_pkthdr.len -= olen; 1690 ip->ip_v = IPVERSION; 1691 ip->ip_hl = sizeof(struct ip) >> 2; 1692 } 1693 1694 u_char inetctlerrmap[PRC_NCMDS] = { 1695 0, 0, 0, 0, 1696 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1697 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1698 EMSGSIZE, EHOSTUNREACH, 0, 0, 1699 0, 0, 0, 0, 1700 ENOPROTOOPT, ECONNREFUSED 1701 }; 1702 1703 /* 1704 * Forward a packet. If some error occurs return the sender 1705 * an icmp packet. Note we can't always generate a meaningful 1706 * icmp message because icmp doesn't have a large enough repertoire 1707 * of codes and types. 1708 * 1709 * If not forwarding, just drop the packet. This could be confusing 1710 * if ipforwarding was zero but some routing protocol was advancing 1711 * us as a gateway to somewhere. However, we must let the routing 1712 * protocol deal with that. 1713 * 1714 * The srcrt parameter indicates whether the packet is being forwarded 1715 * via a source route. 1716 */ 1717 static void 1718 ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop) 1719 { 1720 struct ip *ip = mtod(m, struct ip *); 1721 struct rtentry *rt; 1722 int error, type = 0, code = 0; 1723 struct mbuf *mcopy; 1724 n_long dest; 1725 struct in_addr pkt_dst; 1726 struct ifnet *destifp; 1727 #if defined(IPSEC) || defined(FAST_IPSEC) 1728 struct ifnet dummyifp; 1729 #endif 1730 1731 dest = 0; 1732 /* 1733 * Cache the destination address of the packet; this may be 1734 * changed by use of 'ipfw fwd'. 1735 */ 1736 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 1737 1738 #ifdef DIAGNOSTIC 1739 if (ipprintfs) 1740 printf("forward: src %lx dst %lx ttl %x\n", 1741 (u_long)ip->ip_src.s_addr, (u_long)pkt_dst.s_addr, 1742 ip->ip_ttl); 1743 #endif 1744 1745 1746 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(pkt_dst) == 0) { 1747 ipstat.ips_cantforward++; 1748 m_freem(m); 1749 return; 1750 } 1751 #ifdef IPSTEALTH 1752 if (!ipstealth) { 1753 #endif 1754 if (ip->ip_ttl <= IPTTLDEC) { 1755 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1756 dest, 0); 1757 return; 1758 } 1759 #ifdef IPSTEALTH 1760 } 1761 #endif 1762 1763 if (ip_rtaddr(pkt_dst, &ipforward_rt) == 0) { 1764 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1765 return; 1766 } else 1767 rt = ipforward_rt.ro_rt; 1768 1769 /* 1770 * Save the IP header and at most 8 bytes of the payload, 1771 * in case we need to generate an ICMP message to the src. 1772 * 1773 * XXX this can be optimized a lot by saving the data in a local 1774 * buffer on the stack (72 bytes at most), and only allocating the 1775 * mbuf if really necessary. The vast majority of the packets 1776 * are forwarded without having to send an ICMP back (either 1777 * because unnecessary, or because rate limited), so we are 1778 * really we are wasting a lot of work here. 1779 * 1780 * We don't use m_copy() because it might return a reference 1781 * to a shared cluster. Both this function and ip_output() 1782 * assume exclusive access to the IP header in `m', so any 1783 * data in a cluster may change before we reach icmp_error(). 1784 */ 1785 MGET(mcopy, M_DONTWAIT, m->m_type); 1786 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1787 /* 1788 * It's probably ok if the pkthdr dup fails (because 1789 * the deep copy of the tag chain failed), but for now 1790 * be conservative and just discard the copy since 1791 * code below may some day want the tags. 1792 */ 1793 m_free(mcopy); 1794 mcopy = NULL; 1795 } 1796 if (mcopy != NULL) { 1797 mcopy->m_len = imin((ip->ip_hl << 2) + 8, 1798 (int)ip->ip_len); 1799 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1800 /* 1801 * XXXMAC: Eventually, we may have an explict labeling 1802 * point here. 1803 */ 1804 } 1805 1806 #ifdef IPSTEALTH 1807 if (!ipstealth) { 1808 #endif 1809 ip->ip_ttl -= IPTTLDEC; 1810 #ifdef IPSTEALTH 1811 } 1812 #endif 1813 1814 /* 1815 * If forwarding packet using same interface that it came in on, 1816 * perhaps should send a redirect to sender to shortcut a hop. 1817 * Only send redirect if source is sending directly to us, 1818 * and if packet was not source routed (or has any options). 1819 * Also, don't send redirect if forwarding using a default route 1820 * or a route modified by a redirect. 1821 */ 1822 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1823 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1824 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1825 ipsendredirects && !srcrt && !next_hop) { 1826 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1827 u_long src = ntohl(ip->ip_src.s_addr); 1828 1829 if (RTA(rt) && 1830 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1831 if (rt->rt_flags & RTF_GATEWAY) 1832 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1833 else 1834 dest = pkt_dst.s_addr; 1835 /* Router requirements says to only send host redirects */ 1836 type = ICMP_REDIRECT; 1837 code = ICMP_REDIRECT_HOST; 1838 #ifdef DIAGNOSTIC 1839 if (ipprintfs) 1840 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1841 #endif 1842 } 1843 } 1844 1845 { 1846 struct m_hdr tag; 1847 1848 if (next_hop) { 1849 /* Pass IPFORWARD info if available */ 1850 1851 tag.mh_type = MT_TAG; 1852 tag.mh_flags = PACKET_TAG_IPFORWARD; 1853 tag.mh_data = (caddr_t)next_hop; 1854 tag.mh_next = m; 1855 m = (struct mbuf *)&tag; 1856 } 1857 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1858 IP_FORWARDING, 0, NULL); 1859 } 1860 if (error) 1861 ipstat.ips_cantforward++; 1862 else { 1863 ipstat.ips_forward++; 1864 if (type) 1865 ipstat.ips_redirectsent++; 1866 else { 1867 if (mcopy) { 1868 ipflow_create(&ipforward_rt, mcopy); 1869 m_freem(mcopy); 1870 } 1871 return; 1872 } 1873 } 1874 if (mcopy == NULL) 1875 return; 1876 destifp = NULL; 1877 1878 switch (error) { 1879 1880 case 0: /* forwarded, but need redirect */ 1881 /* type, code set above */ 1882 break; 1883 1884 case ENETUNREACH: /* shouldn't happen, checked above */ 1885 case EHOSTUNREACH: 1886 case ENETDOWN: 1887 case EHOSTDOWN: 1888 default: 1889 type = ICMP_UNREACH; 1890 code = ICMP_UNREACH_HOST; 1891 break; 1892 1893 case EMSGSIZE: 1894 type = ICMP_UNREACH; 1895 code = ICMP_UNREACH_NEEDFRAG; 1896 #ifdef IPSEC 1897 /* 1898 * If the packet is routed over IPsec tunnel, tell the 1899 * originator the tunnel MTU. 1900 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1901 * XXX quickhack!!! 1902 */ 1903 if (ipforward_rt.ro_rt) { 1904 struct secpolicy *sp = NULL; 1905 int ipsecerror; 1906 int ipsechdr; 1907 struct route *ro; 1908 1909 sp = ipsec4_getpolicybyaddr(mcopy, 1910 IPSEC_DIR_OUTBOUND, 1911 IP_FORWARDING, 1912 &ipsecerror); 1913 1914 if (sp == NULL) 1915 destifp = ipforward_rt.ro_rt->rt_ifp; 1916 else { 1917 /* count IPsec header size */ 1918 ipsechdr = ipsec4_hdrsiz(mcopy, 1919 IPSEC_DIR_OUTBOUND, 1920 NULL); 1921 1922 /* 1923 * find the correct route for outer IPv4 1924 * header, compute tunnel MTU. 1925 * 1926 * XXX BUG ALERT 1927 * The "dummyifp" code relies upon the fact 1928 * that icmp_error() touches only ifp->if_mtu. 1929 */ 1930 /*XXX*/ 1931 destifp = NULL; 1932 if (sp->req != NULL 1933 && sp->req->sav != NULL 1934 && sp->req->sav->sah != NULL) { 1935 ro = &sp->req->sav->sah->sa_route; 1936 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1937 dummyifp.if_mtu = 1938 ro->ro_rt->rt_ifp->if_mtu; 1939 dummyifp.if_mtu -= ipsechdr; 1940 destifp = &dummyifp; 1941 } 1942 } 1943 1944 key_freesp(sp); 1945 } 1946 } 1947 #elif FAST_IPSEC 1948 /* 1949 * If the packet is routed over IPsec tunnel, tell the 1950 * originator the tunnel MTU. 1951 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1952 * XXX quickhack!!! 1953 */ 1954 if (ipforward_rt.ro_rt) { 1955 struct secpolicy *sp = NULL; 1956 int ipsecerror; 1957 int ipsechdr; 1958 struct route *ro; 1959 1960 sp = ipsec_getpolicybyaddr(mcopy, 1961 IPSEC_DIR_OUTBOUND, 1962 IP_FORWARDING, 1963 &ipsecerror); 1964 1965 if (sp == NULL) 1966 destifp = ipforward_rt.ro_rt->rt_ifp; 1967 else { 1968 /* count IPsec header size */ 1969 ipsechdr = ipsec4_hdrsiz(mcopy, 1970 IPSEC_DIR_OUTBOUND, 1971 NULL); 1972 1973 /* 1974 * find the correct route for outer IPv4 1975 * header, compute tunnel MTU. 1976 * 1977 * XXX BUG ALERT 1978 * The "dummyifp" code relies upon the fact 1979 * that icmp_error() touches only ifp->if_mtu. 1980 */ 1981 /*XXX*/ 1982 destifp = NULL; 1983 if (sp->req != NULL 1984 && sp->req->sav != NULL 1985 && sp->req->sav->sah != NULL) { 1986 ro = &sp->req->sav->sah->sa_route; 1987 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1988 dummyifp.if_mtu = 1989 ro->ro_rt->rt_ifp->if_mtu; 1990 dummyifp.if_mtu -= ipsechdr; 1991 destifp = &dummyifp; 1992 } 1993 } 1994 1995 KEY_FREESP(&sp); 1996 } 1997 } 1998 #else /* !IPSEC && !FAST_IPSEC */ 1999 if (ipforward_rt.ro_rt) 2000 destifp = ipforward_rt.ro_rt->rt_ifp; 2001 #endif /*IPSEC*/ 2002 ipstat.ips_cantfrag++; 2003 break; 2004 2005 case ENOBUFS: 2006 /* 2007 * A router should not generate ICMP_SOURCEQUENCH as 2008 * required in RFC1812 Requirements for IP Version 4 Routers. 2009 * Source quench could be a big problem under DoS attacks, 2010 * or if the underlying interface is rate-limited. 2011 * Those who need source quench packets may re-enable them 2012 * via the net.inet.ip.sendsourcequench sysctl. 2013 */ 2014 if (ip_sendsourcequench == 0) { 2015 m_freem(mcopy); 2016 return; 2017 } else { 2018 type = ICMP_SOURCEQUENCH; 2019 code = 0; 2020 } 2021 break; 2022 2023 case EACCES: /* ipfw denied packet */ 2024 m_freem(mcopy); 2025 return; 2026 } 2027 icmp_error(mcopy, type, code, dest, destifp); 2028 } 2029 2030 void 2031 ip_savecontrol(inp, mp, ip, m) 2032 register struct inpcb *inp; 2033 register struct mbuf **mp; 2034 register struct ip *ip; 2035 register struct mbuf *m; 2036 { 2037 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2038 struct timeval tv; 2039 2040 microtime(&tv); 2041 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2042 SCM_TIMESTAMP, SOL_SOCKET); 2043 if (*mp) 2044 mp = &(*mp)->m_next; 2045 } 2046 if (inp->inp_flags & INP_RECVDSTADDR) { 2047 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2048 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2049 if (*mp) 2050 mp = &(*mp)->m_next; 2051 } 2052 if (inp->inp_flags & INP_RECVTTL) { 2053 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2054 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2055 if (*mp) 2056 mp = &(*mp)->m_next; 2057 } 2058 #ifdef notyet 2059 /* XXX 2060 * Moving these out of udp_input() made them even more broken 2061 * than they already were. 2062 */ 2063 /* options were tossed already */ 2064 if (inp->inp_flags & INP_RECVOPTS) { 2065 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2066 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2067 if (*mp) 2068 mp = &(*mp)->m_next; 2069 } 2070 /* ip_srcroute doesn't do what we want here, need to fix */ 2071 if (inp->inp_flags & INP_RECVRETOPTS) { 2072 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2073 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2074 if (*mp) 2075 mp = &(*mp)->m_next; 2076 } 2077 #endif 2078 if (inp->inp_flags & INP_RECVIF) { 2079 struct ifnet *ifp; 2080 struct sdlbuf { 2081 struct sockaddr_dl sdl; 2082 u_char pad[32]; 2083 } sdlbuf; 2084 struct sockaddr_dl *sdp; 2085 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2086 2087 if (((ifp = m->m_pkthdr.rcvif)) 2088 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2089 sdp = (struct sockaddr_dl *) 2090 (ifaddr_byindex(ifp->if_index)->ifa_addr); 2091 /* 2092 * Change our mind and don't try copy. 2093 */ 2094 if ((sdp->sdl_family != AF_LINK) 2095 || (sdp->sdl_len > sizeof(sdlbuf))) { 2096 goto makedummy; 2097 } 2098 bcopy(sdp, sdl2, sdp->sdl_len); 2099 } else { 2100 makedummy: 2101 sdl2->sdl_len 2102 = offsetof(struct sockaddr_dl, sdl_data[0]); 2103 sdl2->sdl_family = AF_LINK; 2104 sdl2->sdl_index = 0; 2105 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2106 } 2107 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2108 IP_RECVIF, IPPROTO_IP); 2109 if (*mp) 2110 mp = &(*mp)->m_next; 2111 } 2112 } 2113 2114 /* 2115 * XXX these routines are called from the upper part of the kernel. 2116 * They need to be locked when we remove Giant. 2117 * 2118 * They could also be moved to ip_mroute.c, since all the RSVP 2119 * handling is done there already. 2120 */ 2121 static int ip_rsvp_on; 2122 struct socket *ip_rsvpd; 2123 int 2124 ip_rsvp_init(struct socket *so) 2125 { 2126 if (so->so_type != SOCK_RAW || 2127 so->so_proto->pr_protocol != IPPROTO_RSVP) 2128 return EOPNOTSUPP; 2129 2130 if (ip_rsvpd != NULL) 2131 return EADDRINUSE; 2132 2133 ip_rsvpd = so; 2134 /* 2135 * This may seem silly, but we need to be sure we don't over-increment 2136 * the RSVP counter, in case something slips up. 2137 */ 2138 if (!ip_rsvp_on) { 2139 ip_rsvp_on = 1; 2140 rsvp_on++; 2141 } 2142 2143 return 0; 2144 } 2145 2146 int 2147 ip_rsvp_done(void) 2148 { 2149 ip_rsvpd = NULL; 2150 /* 2151 * This may seem silly, but we need to be sure we don't over-decrement 2152 * the RSVP counter, in case something slips up. 2153 */ 2154 if (ip_rsvp_on) { 2155 ip_rsvp_on = 0; 2156 rsvp_on--; 2157 } 2158 return 0; 2159 } 2160 2161 void 2162 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 2163 { 2164 if (rsvp_input_p) { /* call the real one if loaded */ 2165 rsvp_input_p(m, off); 2166 return; 2167 } 2168 2169 /* Can still get packets with rsvp_on = 0 if there is a local member 2170 * of the group to which the RSVP packet is addressed. But in this 2171 * case we want to throw the packet away. 2172 */ 2173 2174 if (!rsvp_on) { 2175 m_freem(m); 2176 return; 2177 } 2178 2179 if (ip_rsvpd != NULL) { 2180 rip_input(m, off); 2181 return; 2182 } 2183 /* Drop the packet */ 2184 m_freem(m); 2185 }
Cache object: dba71e0b6de95e1d50b8278bda70a4fb
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