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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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 30 * $FreeBSD: releng/6.1/sys/netinet/ip_input.c 156273 2006-03-04 09:16:11Z oleg $ 31 */ 32 33 #include "opt_bootp.h" 34 #include "opt_ipfw.h" 35 #include "opt_ipstealth.h" 36 #include "opt_ipsec.h" 37 #include "opt_mac.h" 38 #include "opt_carp.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/callout.h> 43 #include <sys/mac.h> 44 #include <sys/mbuf.h> 45 #include <sys/malloc.h> 46 #include <sys/domain.h> 47 #include <sys/protosw.h> 48 #include <sys/socket.h> 49 #include <sys/time.h> 50 #include <sys/kernel.h> 51 #include <sys/syslog.h> 52 #include <sys/sysctl.h> 53 54 #include <net/pfil.h> 55 #include <net/if.h> 56 #include <net/if_types.h> 57 #include <net/if_var.h> 58 #include <net/if_dl.h> 59 #include <net/route.h> 60 #include <net/netisr.h> 61 62 #include <netinet/in.h> 63 #include <netinet/in_systm.h> 64 #include <netinet/in_var.h> 65 #include <netinet/ip.h> 66 #include <netinet/in_pcb.h> 67 #include <netinet/ip_var.h> 68 #include <netinet/ip_icmp.h> 69 #include <machine/in_cksum.h> 70 #ifdef DEV_CARP 71 #include <netinet/ip_carp.h> 72 #endif 73 74 #include <sys/socketvar.h> 75 76 /* XXX: Temporary until ipfw_ether and ipfw_bridge are converted. */ 77 #include <netinet/ip_fw.h> 78 #include <netinet/ip_dummynet.h> 79 80 #ifdef IPSEC 81 #include <netinet6/ipsec.h> 82 #include <netkey/key.h> 83 #endif 84 85 #ifdef FAST_IPSEC 86 #include <netipsec/ipsec.h> 87 #include <netipsec/key.h> 88 #endif 89 90 int rsvp_on = 0; 91 92 int ipforwarding = 0; 93 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 94 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 95 96 static int ipsendredirects = 1; /* XXX */ 97 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 98 &ipsendredirects, 0, "Enable sending IP redirects"); 99 100 int ip_defttl = IPDEFTTL; 101 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 102 &ip_defttl, 0, "Maximum TTL on IP packets"); 103 104 static int ip_dosourceroute = 0; 105 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 106 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 107 108 static int ip_acceptsourceroute = 0; 109 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 110 CTLFLAG_RW, &ip_acceptsourceroute, 0, 111 "Enable accepting source routed IP packets"); 112 113 int ip_doopts = 1; /* 0 = ignore, 1 = process, 2 = reject */ 114 SYSCTL_INT(_net_inet_ip, OID_AUTO, process_options, CTLFLAG_RW, 115 &ip_doopts, 0, "Enable IP options processing ([LS]SRR, RR, TS)"); 116 117 static int ip_keepfaith = 0; 118 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 119 &ip_keepfaith, 0, 120 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 121 122 static int ip_sendsourcequench = 0; 123 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 124 &ip_sendsourcequench, 0, 125 "Enable the transmission of source quench packets"); 126 127 int ip_do_randomid = 0; 128 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 129 &ip_do_randomid, 0, 130 "Assign random ip_id values"); 131 132 /* 133 * XXX - Setting ip_checkinterface mostly implements the receive side of 134 * the Strong ES model described in RFC 1122, but since the routing table 135 * and transmit implementation do not implement the Strong ES model, 136 * setting this to 1 results in an odd hybrid. 137 * 138 * XXX - ip_checkinterface currently must be disabled if you use ipnat 139 * to translate the destination address to another local interface. 140 * 141 * XXX - ip_checkinterface must be disabled if you add IP aliases 142 * to the loopback interface instead of the interface where the 143 * packets for those addresses are received. 144 */ 145 static int ip_checkinterface = 0; 146 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 147 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 148 149 #ifdef DIAGNOSTIC 150 static int ipprintfs = 0; 151 #endif 152 153 struct pfil_head inet_pfil_hook; /* Packet filter hooks */ 154 155 static struct ifqueue ipintrq; 156 static int ipqmaxlen = IFQ_MAXLEN; 157 158 extern struct domain inetdomain; 159 extern struct protosw inetsw[]; 160 u_char ip_protox[IPPROTO_MAX]; 161 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 162 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 163 u_long in_ifaddrhmask; /* mask for hash table */ 164 165 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 166 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 167 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 168 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 169 170 struct ipstat ipstat; 171 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 172 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 173 174 /* 175 * IP datagram reassembly. 176 */ 177 #define IPREASS_NHASH_LOG2 6 178 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 179 #define IPREASS_HMASK (IPREASS_NHASH - 1) 180 #define IPREASS_HASH(x,y) \ 181 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 182 183 static uma_zone_t ipq_zone; 184 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 185 static struct mtx ipqlock; 186 187 #define IPQ_LOCK() mtx_lock(&ipqlock) 188 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 189 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 190 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 191 192 static void maxnipq_update(void); 193 194 static int maxnipq; /* Administrative limit on # reass queues. */ 195 static int nipq = 0; /* Total # of reass queues */ 196 SYSCTL_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, &nipq, 0, 197 "Current number of IPv4 fragment reassembly queue entries"); 198 199 static int maxfragsperpacket; 200 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 201 &maxfragsperpacket, 0, 202 "Maximum number of IPv4 fragments allowed per packet"); 203 204 struct callout ipport_tick_callout; 205 206 #ifdef IPCTL_DEFMTU 207 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 208 &ip_mtu, 0, "Default MTU"); 209 #endif 210 211 #ifdef IPSTEALTH 212 int ipstealth = 0; 213 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 214 &ipstealth, 0, ""); 215 #endif 216 217 /* 218 * ipfw_ether and ipfw_bridge hooks. 219 * XXX: Temporary until those are converted to pfil_hooks as well. 220 */ 221 ip_fw_chk_t *ip_fw_chk_ptr = NULL; 222 ip_dn_io_t *ip_dn_io_ptr = NULL; 223 int fw_enable = 1; 224 int fw_one_pass = 1; 225 226 /* 227 * XXX this is ugly. IP options source routing magic. 228 */ 229 struct ipoptrt { 230 struct in_addr dst; /* final destination */ 231 char nop; /* one NOP to align */ 232 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 233 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 234 }; 235 236 struct ipopt_tag { 237 struct m_tag tag; 238 int ip_nhops; 239 struct ipoptrt ip_srcrt; 240 }; 241 242 static void save_rte(struct mbuf *, u_char *, struct in_addr); 243 static int ip_dooptions(struct mbuf *m, int); 244 static void ip_forward(struct mbuf *m, int srcrt); 245 static void ip_freef(struct ipqhead *, struct ipq *); 246 247 /* 248 * IP initialization: fill in IP protocol switch table. 249 * All protocols not implemented in kernel go to raw IP protocol handler. 250 */ 251 void 252 ip_init() 253 { 254 register struct protosw *pr; 255 register int i; 256 257 TAILQ_INIT(&in_ifaddrhead); 258 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 259 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 260 if (pr == NULL) 261 panic("ip_init: PF_INET not found"); 262 263 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 264 for (i = 0; i < IPPROTO_MAX; i++) 265 ip_protox[i] = pr - inetsw; 266 /* 267 * Cycle through IP protocols and put them into the appropriate place 268 * in ip_protox[]. 269 */ 270 for (pr = inetdomain.dom_protosw; 271 pr < inetdomain.dom_protoswNPROTOSW; pr++) 272 if (pr->pr_domain->dom_family == PF_INET && 273 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 274 /* Be careful to only index valid IP protocols. */ 275 if (pr->pr_protocol < IPPROTO_MAX) 276 ip_protox[pr->pr_protocol] = pr - inetsw; 277 } 278 279 /* Initialize packet filter hooks. */ 280 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 281 inet_pfil_hook.ph_af = AF_INET; 282 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 283 printf("%s: WARNING: unable to register pfil hook, " 284 "error %d\n", __func__, i); 285 286 /* Initialize IP reassembly queue. */ 287 IPQ_LOCK_INIT(); 288 for (i = 0; i < IPREASS_NHASH; i++) 289 TAILQ_INIT(&ipq[i]); 290 maxnipq = nmbclusters / 32; 291 maxfragsperpacket = 16; 292 ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 293 NULL, UMA_ALIGN_PTR, 0); 294 maxnipq_update(); 295 296 /* Start ipport_tick. */ 297 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE); 298 ipport_tick(NULL); 299 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL, 300 SHUTDOWN_PRI_DEFAULT); 301 302 /* Initialize various other remaining things. */ 303 ip_id = time_second & 0xffff; 304 ipintrq.ifq_maxlen = ipqmaxlen; 305 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 306 netisr_register(NETISR_IP, ip_input, &ipintrq, NETISR_MPSAFE); 307 } 308 309 void ip_fini(xtp) 310 void *xtp; 311 { 312 callout_stop(&ipport_tick_callout); 313 } 314 315 /* 316 * Ip input routine. Checksum and byte swap header. If fragmented 317 * try to reassemble. Process options. Pass to next level. 318 */ 319 void 320 ip_input(struct mbuf *m) 321 { 322 struct ip *ip = NULL; 323 struct in_ifaddr *ia = NULL; 324 struct ifaddr *ifa; 325 int checkif, hlen = 0; 326 u_short sum; 327 int dchg = 0; /* dest changed after fw */ 328 struct in_addr odst; /* original dst address */ 329 #ifdef FAST_IPSEC 330 struct m_tag *mtag; 331 struct tdb_ident *tdbi; 332 struct secpolicy *sp; 333 int s, error; 334 #endif /* FAST_IPSEC */ 335 336 M_ASSERTPKTHDR(m); 337 338 if (m->m_flags & M_FASTFWD_OURS) { 339 /* 340 * Firewall or NAT changed destination to local. 341 * We expect ip_len and ip_off to be in host byte order. 342 */ 343 m->m_flags &= ~M_FASTFWD_OURS; 344 /* Set up some basics that will be used later. */ 345 ip = mtod(m, struct ip *); 346 hlen = ip->ip_hl << 2; 347 goto ours; 348 } 349 350 ipstat.ips_total++; 351 352 if (m->m_pkthdr.len < sizeof(struct ip)) 353 goto tooshort; 354 355 if (m->m_len < sizeof (struct ip) && 356 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 357 ipstat.ips_toosmall++; 358 return; 359 } 360 ip = mtod(m, struct ip *); 361 362 if (ip->ip_v != IPVERSION) { 363 ipstat.ips_badvers++; 364 goto bad; 365 } 366 367 hlen = ip->ip_hl << 2; 368 if (hlen < sizeof(struct ip)) { /* minimum header length */ 369 ipstat.ips_badhlen++; 370 goto bad; 371 } 372 if (hlen > m->m_len) { 373 if ((m = m_pullup(m, hlen)) == NULL) { 374 ipstat.ips_badhlen++; 375 return; 376 } 377 ip = mtod(m, struct ip *); 378 } 379 380 /* 127/8 must not appear on wire - RFC1122 */ 381 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 382 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 383 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 384 ipstat.ips_badaddr++; 385 goto bad; 386 } 387 } 388 389 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 390 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 391 } else { 392 if (hlen == sizeof(struct ip)) { 393 sum = in_cksum_hdr(ip); 394 } else { 395 sum = in_cksum(m, hlen); 396 } 397 } 398 if (sum) { 399 ipstat.ips_badsum++; 400 goto bad; 401 } 402 403 #ifdef ALTQ 404 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 405 /* packet is dropped by traffic conditioner */ 406 return; 407 #endif 408 409 /* 410 * Convert fields to host representation. 411 */ 412 ip->ip_len = ntohs(ip->ip_len); 413 if (ip->ip_len < hlen) { 414 ipstat.ips_badlen++; 415 goto bad; 416 } 417 ip->ip_off = ntohs(ip->ip_off); 418 419 /* 420 * Check that the amount of data in the buffers 421 * is as at least much as the IP header would have us expect. 422 * Trim mbufs if longer than we expect. 423 * Drop packet if shorter than we expect. 424 */ 425 if (m->m_pkthdr.len < ip->ip_len) { 426 tooshort: 427 ipstat.ips_tooshort++; 428 goto bad; 429 } 430 if (m->m_pkthdr.len > ip->ip_len) { 431 if (m->m_len == m->m_pkthdr.len) { 432 m->m_len = ip->ip_len; 433 m->m_pkthdr.len = ip->ip_len; 434 } else 435 m_adj(m, ip->ip_len - m->m_pkthdr.len); 436 } 437 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 438 /* 439 * Bypass packet filtering for packets from a tunnel (gif). 440 */ 441 if (ipsec_getnhist(m)) 442 goto passin; 443 #endif 444 #if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF) 445 /* 446 * Bypass packet filtering for packets from a tunnel (gif). 447 */ 448 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 449 goto passin; 450 #endif 451 452 /* 453 * Run through list of hooks for input packets. 454 * 455 * NB: Beware of the destination address changing (e.g. 456 * by NAT rewriting). When this happens, tell 457 * ip_forward to do the right thing. 458 */ 459 460 /* Jump over all PFIL processing if hooks are not active. */ 461 if (inet_pfil_hook.ph_busy_count == -1) 462 goto passin; 463 464 odst = ip->ip_dst; 465 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 466 PFIL_IN, NULL) != 0) 467 return; 468 if (m == NULL) /* consumed by filter */ 469 return; 470 471 ip = mtod(m, struct ip *); 472 dchg = (odst.s_addr != ip->ip_dst.s_addr); 473 474 #ifdef IPFIREWALL_FORWARD 475 if (m->m_flags & M_FASTFWD_OURS) { 476 m->m_flags &= ~M_FASTFWD_OURS; 477 goto ours; 478 } 479 #ifndef IPFIREWALL_FORWARD_EXTENDED 480 dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL); 481 #else 482 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 483 /* 484 * Directly ship on the packet. This allows to forward packets 485 * that were destined for us to some other directly connected 486 * host. 487 */ 488 ip_forward(m, dchg); 489 return; 490 } 491 #endif /* IPFIREWALL_FORWARD_EXTENDED */ 492 #endif /* IPFIREWALL_FORWARD */ 493 494 passin: 495 /* 496 * Process options and, if not destined for us, 497 * ship it on. ip_dooptions returns 1 when an 498 * error was detected (causing an icmp message 499 * to be sent and the original packet to be freed). 500 */ 501 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 502 return; 503 504 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 505 * matter if it is destined to another node, or whether it is 506 * a multicast one, RSVP wants it! and prevents it from being forwarded 507 * anywhere else. Also checks if the rsvp daemon is running before 508 * grabbing the packet. 509 */ 510 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 511 goto ours; 512 513 /* 514 * Check our list of addresses, to see if the packet is for us. 515 * If we don't have any addresses, assume any unicast packet 516 * we receive might be for us (and let the upper layers deal 517 * with it). 518 */ 519 if (TAILQ_EMPTY(&in_ifaddrhead) && 520 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 521 goto ours; 522 523 /* 524 * Enable a consistency check between the destination address 525 * and the arrival interface for a unicast packet (the RFC 1122 526 * strong ES model) if IP forwarding is disabled and the packet 527 * is not locally generated and the packet is not subject to 528 * 'ipfw fwd'. 529 * 530 * XXX - Checking also should be disabled if the destination 531 * address is ipnat'ed to a different interface. 532 * 533 * XXX - Checking is incompatible with IP aliases added 534 * to the loopback interface instead of the interface where 535 * the packets are received. 536 * 537 * XXX - This is the case for carp vhost IPs as well so we 538 * insert a workaround. If the packet got here, we already 539 * checked with carp_iamatch() and carp_forus(). 540 */ 541 checkif = ip_checkinterface && (ipforwarding == 0) && 542 m->m_pkthdr.rcvif != NULL && 543 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 544 #ifdef DEV_CARP 545 !m->m_pkthdr.rcvif->if_carp && 546 #endif 547 (dchg == 0); 548 549 /* 550 * Check for exact addresses in the hash bucket. 551 */ 552 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 553 /* 554 * If the address matches, verify that the packet 555 * arrived via the correct interface if checking is 556 * enabled. 557 */ 558 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 559 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 560 goto ours; 561 } 562 /* 563 * Check for broadcast addresses. 564 * 565 * Only accept broadcast packets that arrive via the matching 566 * interface. Reception of forwarded directed broadcasts would 567 * be handled via ip_forward() and ether_output() with the loopback 568 * into the stack for SIMPLEX interfaces handled by ether_output(). 569 */ 570 if (m->m_pkthdr.rcvif != NULL && 571 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 572 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 573 if (ifa->ifa_addr->sa_family != AF_INET) 574 continue; 575 ia = ifatoia(ifa); 576 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 577 ip->ip_dst.s_addr) 578 goto ours; 579 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 580 goto ours; 581 #ifdef BOOTP_COMPAT 582 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 583 goto ours; 584 #endif 585 } 586 } 587 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 588 struct in_multi *inm; 589 if (ip_mrouter) { 590 /* 591 * If we are acting as a multicast router, all 592 * incoming multicast packets are passed to the 593 * kernel-level multicast forwarding function. 594 * The packet is returned (relatively) intact; if 595 * ip_mforward() returns a non-zero value, the packet 596 * must be discarded, else it may be accepted below. 597 */ 598 if (ip_mforward && 599 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 600 ipstat.ips_cantforward++; 601 m_freem(m); 602 return; 603 } 604 605 /* 606 * The process-level routing daemon needs to receive 607 * all multicast IGMP packets, whether or not this 608 * host belongs to their destination groups. 609 */ 610 if (ip->ip_p == IPPROTO_IGMP) 611 goto ours; 612 ipstat.ips_forward++; 613 } 614 /* 615 * See if we belong to the destination multicast group on the 616 * arrival interface. 617 */ 618 IN_MULTI_LOCK(); 619 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 620 IN_MULTI_UNLOCK(); 621 if (inm == NULL) { 622 ipstat.ips_notmember++; 623 m_freem(m); 624 return; 625 } 626 goto ours; 627 } 628 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 629 goto ours; 630 if (ip->ip_dst.s_addr == INADDR_ANY) 631 goto ours; 632 633 /* 634 * FAITH(Firewall Aided Internet Translator) 635 */ 636 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 637 if (ip_keepfaith) { 638 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 639 goto ours; 640 } 641 m_freem(m); 642 return; 643 } 644 645 /* 646 * Not for us; forward if possible and desirable. 647 */ 648 if (ipforwarding == 0) { 649 ipstat.ips_cantforward++; 650 m_freem(m); 651 } else { 652 #ifdef IPSEC 653 /* 654 * Enforce inbound IPsec SPD. 655 */ 656 if (ipsec4_in_reject(m, NULL)) { 657 ipsecstat.in_polvio++; 658 goto bad; 659 } 660 #endif /* IPSEC */ 661 #ifdef FAST_IPSEC 662 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 663 s = splnet(); 664 if (mtag != NULL) { 665 tdbi = (struct tdb_ident *)(mtag + 1); 666 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 667 } else { 668 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 669 IP_FORWARDING, &error); 670 } 671 if (sp == NULL) { /* NB: can happen if error */ 672 splx(s); 673 /*XXX error stat???*/ 674 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 675 goto bad; 676 } 677 678 /* 679 * Check security policy against packet attributes. 680 */ 681 error = ipsec_in_reject(sp, m); 682 KEY_FREESP(&sp); 683 splx(s); 684 if (error) { 685 ipstat.ips_cantforward++; 686 goto bad; 687 } 688 #endif /* FAST_IPSEC */ 689 ip_forward(m, dchg); 690 } 691 return; 692 693 ours: 694 #ifdef IPSTEALTH 695 /* 696 * IPSTEALTH: Process non-routing options only 697 * if the packet is destined for us. 698 */ 699 if (ipstealth && hlen > sizeof (struct ip) && 700 ip_dooptions(m, 1)) 701 return; 702 #endif /* IPSTEALTH */ 703 704 /* Count the packet in the ip address stats */ 705 if (ia != NULL) { 706 ia->ia_ifa.if_ipackets++; 707 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 708 } 709 710 /* 711 * Attempt reassembly; if it succeeds, proceed. 712 * ip_reass() will return a different mbuf. 713 */ 714 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 715 m = ip_reass(m); 716 if (m == NULL) 717 return; 718 ip = mtod(m, struct ip *); 719 /* Get the header length of the reassembled packet */ 720 hlen = ip->ip_hl << 2; 721 } 722 723 /* 724 * Further protocols expect the packet length to be w/o the 725 * IP header. 726 */ 727 ip->ip_len -= hlen; 728 729 #ifdef IPSEC 730 /* 731 * enforce IPsec policy checking if we are seeing last header. 732 * note that we do not visit this with protocols with pcb layer 733 * code - like udp/tcp/raw ip. 734 */ 735 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 736 ipsec4_in_reject(m, NULL)) { 737 ipsecstat.in_polvio++; 738 goto bad; 739 } 740 #endif 741 #if FAST_IPSEC 742 /* 743 * enforce IPsec policy checking if we are seeing last header. 744 * note that we do not visit this with protocols with pcb layer 745 * code - like udp/tcp/raw ip. 746 */ 747 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 748 /* 749 * Check if the packet has already had IPsec processing 750 * done. If so, then just pass it along. This tag gets 751 * set during AH, ESP, etc. input handling, before the 752 * packet is returned to the ip input queue for delivery. 753 */ 754 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 755 s = splnet(); 756 if (mtag != NULL) { 757 tdbi = (struct tdb_ident *)(mtag + 1); 758 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 759 } else { 760 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 761 IP_FORWARDING, &error); 762 } 763 if (sp != NULL) { 764 /* 765 * Check security policy against packet attributes. 766 */ 767 error = ipsec_in_reject(sp, m); 768 KEY_FREESP(&sp); 769 } else { 770 /* XXX error stat??? */ 771 error = EINVAL; 772 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 773 goto bad; 774 } 775 splx(s); 776 if (error) 777 goto bad; 778 } 779 #endif /* FAST_IPSEC */ 780 781 /* 782 * Switch out to protocol's input routine. 783 */ 784 ipstat.ips_delivered++; 785 786 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 787 return; 788 bad: 789 m_freem(m); 790 } 791 792 /* 793 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 794 * max has slightly different semantics than the sysctl, for historical 795 * reasons. 796 */ 797 static void 798 maxnipq_update(void) 799 { 800 801 /* 802 * -1 for unlimited allocation. 803 */ 804 if (maxnipq < 0) 805 uma_zone_set_max(ipq_zone, 0); 806 /* 807 * Positive number for specific bound. 808 */ 809 if (maxnipq > 0) 810 uma_zone_set_max(ipq_zone, maxnipq); 811 /* 812 * Zero specifies no further fragment queue allocation -- set the 813 * bound very low, but rely on implementation elsewhere to actually 814 * prevent allocation and reclaim current queues. 815 */ 816 if (maxnipq == 0) 817 uma_zone_set_max(ipq_zone, 1); 818 } 819 820 static int 821 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 822 { 823 int error, i; 824 825 i = maxnipq; 826 error = sysctl_handle_int(oidp, &i, 0, req); 827 if (error || !req->newptr) 828 return (error); 829 830 /* 831 * XXXRW: Might be a good idea to sanity check the argument and place 832 * an extreme upper bound. 833 */ 834 if (i < -1) 835 return (EINVAL); 836 maxnipq = i; 837 maxnipq_update(); 838 return (0); 839 } 840 841 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 842 NULL, 0, sysctl_maxnipq, "I", 843 "Maximum number of IPv4 fragment reassembly queue entries"); 844 845 /* 846 * Take incoming datagram fragment and try to reassemble it into 847 * whole datagram. If the argument is the first fragment or one 848 * in between the function will return NULL and store the mbuf 849 * in the fragment chain. If the argument is the last fragment 850 * the packet will be reassembled and the pointer to the new 851 * mbuf returned for further processing. Only m_tags attached 852 * to the first packet/fragment are preserved. 853 * The IP header is *NOT* adjusted out of iplen. 854 */ 855 856 struct mbuf * 857 ip_reass(struct mbuf *m) 858 { 859 struct ip *ip; 860 struct mbuf *p, *q, *nq, *t; 861 struct ipq *fp = NULL; 862 struct ipqhead *head; 863 int i, hlen, next; 864 u_int8_t ecn, ecn0; 865 u_short hash; 866 867 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 868 if (maxnipq == 0 || maxfragsperpacket == 0) { 869 ipstat.ips_fragments++; 870 ipstat.ips_fragdropped++; 871 m_freem(m); 872 return (NULL); 873 } 874 875 ip = mtod(m, struct ip *); 876 hlen = ip->ip_hl << 2; 877 878 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 879 head = &ipq[hash]; 880 IPQ_LOCK(); 881 882 /* 883 * Look for queue of fragments 884 * of this datagram. 885 */ 886 TAILQ_FOREACH(fp, head, ipq_list) 887 if (ip->ip_id == fp->ipq_id && 888 ip->ip_src.s_addr == fp->ipq_src.s_addr && 889 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 890 #ifdef MAC 891 mac_fragment_match(m, fp) && 892 #endif 893 ip->ip_p == fp->ipq_p) 894 goto found; 895 896 fp = NULL; 897 898 /* 899 * Attempt to trim the number of allocated fragment queues if it 900 * exceeds the administrative limit. 901 */ 902 if ((nipq > maxnipq) && (maxnipq > 0)) { 903 /* 904 * drop something from the tail of the current queue 905 * before proceeding further 906 */ 907 struct ipq *q = TAILQ_LAST(head, ipqhead); 908 if (q == NULL) { /* gak */ 909 for (i = 0; i < IPREASS_NHASH; i++) { 910 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 911 if (r) { 912 ipstat.ips_fragtimeout += r->ipq_nfrags; 913 ip_freef(&ipq[i], r); 914 break; 915 } 916 } 917 } else { 918 ipstat.ips_fragtimeout += q->ipq_nfrags; 919 ip_freef(head, q); 920 } 921 } 922 923 found: 924 /* 925 * Adjust ip_len to not reflect header, 926 * convert offset of this to bytes. 927 */ 928 ip->ip_len -= hlen; 929 if (ip->ip_off & IP_MF) { 930 /* 931 * Make sure that fragments have a data length 932 * that's a non-zero multiple of 8 bytes. 933 */ 934 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 935 ipstat.ips_toosmall++; /* XXX */ 936 goto dropfrag; 937 } 938 m->m_flags |= M_FRAG; 939 } else 940 m->m_flags &= ~M_FRAG; 941 ip->ip_off <<= 3; 942 943 944 /* 945 * Attempt reassembly; if it succeeds, proceed. 946 * ip_reass() will return a different mbuf. 947 */ 948 ipstat.ips_fragments++; 949 m->m_pkthdr.header = ip; 950 951 /* Previous ip_reass() started here. */ 952 /* 953 * Presence of header sizes in mbufs 954 * would confuse code below. 955 */ 956 m->m_data += hlen; 957 m->m_len -= hlen; 958 959 /* 960 * If first fragment to arrive, create a reassembly queue. 961 */ 962 if (fp == NULL) { 963 fp = uma_zalloc(ipq_zone, M_NOWAIT); 964 if (fp == NULL) 965 goto dropfrag; 966 #ifdef MAC 967 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 968 uma_zfree(ipq_zone, fp); 969 goto dropfrag; 970 } 971 mac_create_ipq(m, fp); 972 #endif 973 TAILQ_INSERT_HEAD(head, fp, ipq_list); 974 nipq++; 975 fp->ipq_nfrags = 1; 976 fp->ipq_ttl = IPFRAGTTL; 977 fp->ipq_p = ip->ip_p; 978 fp->ipq_id = ip->ip_id; 979 fp->ipq_src = ip->ip_src; 980 fp->ipq_dst = ip->ip_dst; 981 fp->ipq_frags = m; 982 m->m_nextpkt = NULL; 983 goto done; 984 } else { 985 fp->ipq_nfrags++; 986 #ifdef MAC 987 mac_update_ipq(m, fp); 988 #endif 989 } 990 991 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 992 993 /* 994 * Handle ECN by comparing this segment with the first one; 995 * if CE is set, do not lose CE. 996 * drop if CE and not-ECT are mixed for the same packet. 997 */ 998 ecn = ip->ip_tos & IPTOS_ECN_MASK; 999 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 1000 if (ecn == IPTOS_ECN_CE) { 1001 if (ecn0 == IPTOS_ECN_NOTECT) 1002 goto dropfrag; 1003 if (ecn0 != IPTOS_ECN_CE) 1004 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 1005 } 1006 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 1007 goto dropfrag; 1008 1009 /* 1010 * Find a segment which begins after this one does. 1011 */ 1012 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1013 if (GETIP(q)->ip_off > ip->ip_off) 1014 break; 1015 1016 /* 1017 * If there is a preceding segment, it may provide some of 1018 * our data already. If so, drop the data from the incoming 1019 * segment. If it provides all of our data, drop us, otherwise 1020 * stick new segment in the proper place. 1021 * 1022 * If some of the data is dropped from the the preceding 1023 * segment, then it's checksum is invalidated. 1024 */ 1025 if (p) { 1026 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1027 if (i > 0) { 1028 if (i >= ip->ip_len) 1029 goto dropfrag; 1030 m_adj(m, i); 1031 m->m_pkthdr.csum_flags = 0; 1032 ip->ip_off += i; 1033 ip->ip_len -= i; 1034 } 1035 m->m_nextpkt = p->m_nextpkt; 1036 p->m_nextpkt = m; 1037 } else { 1038 m->m_nextpkt = fp->ipq_frags; 1039 fp->ipq_frags = m; 1040 } 1041 1042 /* 1043 * While we overlap succeeding segments trim them or, 1044 * if they are completely covered, dequeue them. 1045 */ 1046 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1047 q = nq) { 1048 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1049 if (i < GETIP(q)->ip_len) { 1050 GETIP(q)->ip_len -= i; 1051 GETIP(q)->ip_off += i; 1052 m_adj(q, i); 1053 q->m_pkthdr.csum_flags = 0; 1054 break; 1055 } 1056 nq = q->m_nextpkt; 1057 m->m_nextpkt = nq; 1058 ipstat.ips_fragdropped++; 1059 fp->ipq_nfrags--; 1060 m_freem(q); 1061 } 1062 1063 /* 1064 * Check for complete reassembly and perform frag per packet 1065 * limiting. 1066 * 1067 * Frag limiting is performed here so that the nth frag has 1068 * a chance to complete the packet before we drop the packet. 1069 * As a result, n+1 frags are actually allowed per packet, but 1070 * only n will ever be stored. (n = maxfragsperpacket.) 1071 * 1072 */ 1073 next = 0; 1074 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1075 if (GETIP(q)->ip_off != next) { 1076 if (fp->ipq_nfrags > maxfragsperpacket) { 1077 ipstat.ips_fragdropped += fp->ipq_nfrags; 1078 ip_freef(head, fp); 1079 } 1080 goto done; 1081 } 1082 next += GETIP(q)->ip_len; 1083 } 1084 /* Make sure the last packet didn't have the IP_MF flag */ 1085 if (p->m_flags & M_FRAG) { 1086 if (fp->ipq_nfrags > maxfragsperpacket) { 1087 ipstat.ips_fragdropped += fp->ipq_nfrags; 1088 ip_freef(head, fp); 1089 } 1090 goto done; 1091 } 1092 1093 /* 1094 * Reassembly is complete. Make sure the packet is a sane size. 1095 */ 1096 q = fp->ipq_frags; 1097 ip = GETIP(q); 1098 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1099 ipstat.ips_toolong++; 1100 ipstat.ips_fragdropped += fp->ipq_nfrags; 1101 ip_freef(head, fp); 1102 goto done; 1103 } 1104 1105 /* 1106 * Concatenate fragments. 1107 */ 1108 m = q; 1109 t = m->m_next; 1110 m->m_next = NULL; 1111 m_cat(m, t); 1112 nq = q->m_nextpkt; 1113 q->m_nextpkt = NULL; 1114 for (q = nq; q != NULL; q = nq) { 1115 nq = q->m_nextpkt; 1116 q->m_nextpkt = NULL; 1117 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1118 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1119 m_cat(m, q); 1120 } 1121 /* 1122 * In order to do checksumming faster we do 'end-around carry' here 1123 * (and not in for{} loop), though it implies we are not going to 1124 * reassemble more than 64k fragments. 1125 */ 1126 m->m_pkthdr.csum_data = 1127 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1128 #ifdef MAC 1129 mac_create_datagram_from_ipq(fp, m); 1130 mac_destroy_ipq(fp); 1131 #endif 1132 1133 /* 1134 * Create header for new ip packet by modifying header of first 1135 * packet; dequeue and discard fragment reassembly header. 1136 * Make header visible. 1137 */ 1138 ip->ip_len = (ip->ip_hl << 2) + next; 1139 ip->ip_src = fp->ipq_src; 1140 ip->ip_dst = fp->ipq_dst; 1141 TAILQ_REMOVE(head, fp, ipq_list); 1142 nipq--; 1143 uma_zfree(ipq_zone, fp); 1144 m->m_len += (ip->ip_hl << 2); 1145 m->m_data -= (ip->ip_hl << 2); 1146 /* some debugging cruft by sklower, below, will go away soon */ 1147 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1148 m_fixhdr(m); 1149 ipstat.ips_reassembled++; 1150 IPQ_UNLOCK(); 1151 return (m); 1152 1153 dropfrag: 1154 ipstat.ips_fragdropped++; 1155 if (fp != NULL) 1156 fp->ipq_nfrags--; 1157 m_freem(m); 1158 done: 1159 IPQ_UNLOCK(); 1160 return (NULL); 1161 1162 #undef GETIP 1163 } 1164 1165 /* 1166 * Free a fragment reassembly header and all 1167 * associated datagrams. 1168 */ 1169 static void 1170 ip_freef(fhp, fp) 1171 struct ipqhead *fhp; 1172 struct ipq *fp; 1173 { 1174 register struct mbuf *q; 1175 1176 IPQ_LOCK_ASSERT(); 1177 1178 while (fp->ipq_frags) { 1179 q = fp->ipq_frags; 1180 fp->ipq_frags = q->m_nextpkt; 1181 m_freem(q); 1182 } 1183 TAILQ_REMOVE(fhp, fp, ipq_list); 1184 uma_zfree(ipq_zone, fp); 1185 nipq--; 1186 } 1187 1188 /* 1189 * IP timer processing; 1190 * if a timer expires on a reassembly 1191 * queue, discard it. 1192 */ 1193 void 1194 ip_slowtimo() 1195 { 1196 register struct ipq *fp; 1197 int i; 1198 1199 IPQ_LOCK(); 1200 for (i = 0; i < IPREASS_NHASH; i++) { 1201 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1202 struct ipq *fpp; 1203 1204 fpp = fp; 1205 fp = TAILQ_NEXT(fp, ipq_list); 1206 if(--fpp->ipq_ttl == 0) { 1207 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1208 ip_freef(&ipq[i], fpp); 1209 } 1210 } 1211 } 1212 /* 1213 * If we are over the maximum number of fragments 1214 * (due to the limit being lowered), drain off 1215 * enough to get down to the new limit. 1216 */ 1217 if (maxnipq >= 0 && nipq > maxnipq) { 1218 for (i = 0; i < IPREASS_NHASH; i++) { 1219 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1220 ipstat.ips_fragdropped += 1221 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1222 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1223 } 1224 } 1225 } 1226 IPQ_UNLOCK(); 1227 } 1228 1229 /* 1230 * Drain off all datagram fragments. 1231 */ 1232 void 1233 ip_drain() 1234 { 1235 int i; 1236 1237 IPQ_LOCK(); 1238 for (i = 0; i < IPREASS_NHASH; i++) { 1239 while(!TAILQ_EMPTY(&ipq[i])) { 1240 ipstat.ips_fragdropped += 1241 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1242 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1243 } 1244 } 1245 IPQ_UNLOCK(); 1246 in_rtqdrain(); 1247 } 1248 1249 /* 1250 * The protocol to be inserted into ip_protox[] must be already registered 1251 * in inetsw[], either statically or through pf_proto_register(). 1252 */ 1253 int 1254 ipproto_register(u_char ipproto) 1255 { 1256 struct protosw *pr; 1257 1258 /* Sanity checks. */ 1259 if (ipproto == 0) 1260 return (EPROTONOSUPPORT); 1261 1262 /* 1263 * The protocol slot must not be occupied by another protocol 1264 * already. An index pointing to IPPROTO_RAW is unused. 1265 */ 1266 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1267 if (pr == NULL) 1268 return (EPFNOSUPPORT); 1269 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1270 return (EEXIST); 1271 1272 /* Find the protocol position in inetsw[] and set the index. */ 1273 for (pr = inetdomain.dom_protosw; 1274 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1275 if (pr->pr_domain->dom_family == PF_INET && 1276 pr->pr_protocol && pr->pr_protocol == ipproto) { 1277 /* Be careful to only index valid IP protocols. */ 1278 if (pr->pr_protocol < IPPROTO_MAX) { 1279 ip_protox[pr->pr_protocol] = pr - inetsw; 1280 return (0); 1281 } else 1282 return (EINVAL); 1283 } 1284 } 1285 return (EPROTONOSUPPORT); 1286 } 1287 1288 int 1289 ipproto_unregister(u_char ipproto) 1290 { 1291 struct protosw *pr; 1292 1293 /* Sanity checks. */ 1294 if (ipproto == 0) 1295 return (EPROTONOSUPPORT); 1296 1297 /* Check if the protocol was indeed registered. */ 1298 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1299 if (pr == NULL) 1300 return (EPFNOSUPPORT); 1301 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1302 return (ENOENT); 1303 1304 /* Reset the protocol slot to IPPROTO_RAW. */ 1305 ip_protox[ipproto] = pr - inetsw; 1306 return (0); 1307 } 1308 1309 1310 /* 1311 * Do option processing on a datagram, 1312 * possibly discarding it if bad options are encountered, 1313 * or forwarding it if source-routed. 1314 * The pass argument is used when operating in the IPSTEALTH 1315 * mode to tell what options to process: 1316 * [LS]SRR (pass 0) or the others (pass 1). 1317 * The reason for as many as two passes is that when doing IPSTEALTH, 1318 * non-routing options should be processed only if the packet is for us. 1319 * Returns 1 if packet has been forwarded/freed, 1320 * 0 if the packet should be processed further. 1321 */ 1322 static int 1323 ip_dooptions(struct mbuf *m, int pass) 1324 { 1325 struct ip *ip = mtod(m, struct ip *); 1326 u_char *cp; 1327 struct in_ifaddr *ia; 1328 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1329 struct in_addr *sin, dst; 1330 n_time ntime; 1331 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 1332 1333 /* ignore or reject packets with IP options */ 1334 if (ip_doopts == 0) 1335 return 0; 1336 else if (ip_doopts == 2) { 1337 type = ICMP_UNREACH; 1338 code = ICMP_UNREACH_FILTER_PROHIB; 1339 goto bad; 1340 } 1341 1342 dst = ip->ip_dst; 1343 cp = (u_char *)(ip + 1); 1344 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1345 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1346 opt = cp[IPOPT_OPTVAL]; 1347 if (opt == IPOPT_EOL) 1348 break; 1349 if (opt == IPOPT_NOP) 1350 optlen = 1; 1351 else { 1352 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1353 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1354 goto bad; 1355 } 1356 optlen = cp[IPOPT_OLEN]; 1357 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1358 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1359 goto bad; 1360 } 1361 } 1362 switch (opt) { 1363 1364 default: 1365 break; 1366 1367 /* 1368 * Source routing with record. 1369 * Find interface with current destination address. 1370 * If none on this machine then drop if strictly routed, 1371 * or do nothing if loosely routed. 1372 * Record interface address and bring up next address 1373 * component. If strictly routed make sure next 1374 * address is on directly accessible net. 1375 */ 1376 case IPOPT_LSRR: 1377 case IPOPT_SSRR: 1378 #ifdef IPSTEALTH 1379 if (ipstealth && pass > 0) 1380 break; 1381 #endif 1382 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1383 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1384 goto bad; 1385 } 1386 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1387 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1388 goto bad; 1389 } 1390 ipaddr.sin_addr = ip->ip_dst; 1391 ia = (struct in_ifaddr *) 1392 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1393 if (ia == NULL) { 1394 if (opt == IPOPT_SSRR) { 1395 type = ICMP_UNREACH; 1396 code = ICMP_UNREACH_SRCFAIL; 1397 goto bad; 1398 } 1399 if (!ip_dosourceroute) 1400 goto nosourcerouting; 1401 /* 1402 * Loose routing, and not at next destination 1403 * yet; nothing to do except forward. 1404 */ 1405 break; 1406 } 1407 off--; /* 0 origin */ 1408 if (off > optlen - (int)sizeof(struct in_addr)) { 1409 /* 1410 * End of source route. Should be for us. 1411 */ 1412 if (!ip_acceptsourceroute) 1413 goto nosourcerouting; 1414 save_rte(m, cp, ip->ip_src); 1415 break; 1416 } 1417 #ifdef IPSTEALTH 1418 if (ipstealth) 1419 goto dropit; 1420 #endif 1421 if (!ip_dosourceroute) { 1422 if (ipforwarding) { 1423 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1424 /* 1425 * Acting as a router, so generate ICMP 1426 */ 1427 nosourcerouting: 1428 strcpy(buf, inet_ntoa(ip->ip_dst)); 1429 log(LOG_WARNING, 1430 "attempted source route from %s to %s\n", 1431 inet_ntoa(ip->ip_src), buf); 1432 type = ICMP_UNREACH; 1433 code = ICMP_UNREACH_SRCFAIL; 1434 goto bad; 1435 } else { 1436 /* 1437 * Not acting as a router, so silently drop. 1438 */ 1439 #ifdef IPSTEALTH 1440 dropit: 1441 #endif 1442 ipstat.ips_cantforward++; 1443 m_freem(m); 1444 return (1); 1445 } 1446 } 1447 1448 /* 1449 * locate outgoing interface 1450 */ 1451 (void)memcpy(&ipaddr.sin_addr, cp + off, 1452 sizeof(ipaddr.sin_addr)); 1453 1454 if (opt == IPOPT_SSRR) { 1455 #define INA struct in_ifaddr * 1456 #define SA struct sockaddr * 1457 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == NULL) 1458 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1459 } else 1460 ia = ip_rtaddr(ipaddr.sin_addr); 1461 if (ia == NULL) { 1462 type = ICMP_UNREACH; 1463 code = ICMP_UNREACH_SRCFAIL; 1464 goto bad; 1465 } 1466 ip->ip_dst = ipaddr.sin_addr; 1467 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1468 sizeof(struct in_addr)); 1469 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1470 /* 1471 * Let ip_intr's mcast routing check handle mcast pkts 1472 */ 1473 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1474 break; 1475 1476 case IPOPT_RR: 1477 #ifdef IPSTEALTH 1478 if (ipstealth && pass == 0) 1479 break; 1480 #endif 1481 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1482 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1483 goto bad; 1484 } 1485 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1486 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1487 goto bad; 1488 } 1489 /* 1490 * If no space remains, ignore. 1491 */ 1492 off--; /* 0 origin */ 1493 if (off > optlen - (int)sizeof(struct in_addr)) 1494 break; 1495 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1496 sizeof(ipaddr.sin_addr)); 1497 /* 1498 * locate outgoing interface; if we're the destination, 1499 * use the incoming interface (should be same). 1500 */ 1501 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1502 (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) { 1503 type = ICMP_UNREACH; 1504 code = ICMP_UNREACH_HOST; 1505 goto bad; 1506 } 1507 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1508 sizeof(struct in_addr)); 1509 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1510 break; 1511 1512 case IPOPT_TS: 1513 #ifdef IPSTEALTH 1514 if (ipstealth && pass == 0) 1515 break; 1516 #endif 1517 code = cp - (u_char *)ip; 1518 if (optlen < 4 || optlen > 40) { 1519 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1520 goto bad; 1521 } 1522 if ((off = cp[IPOPT_OFFSET]) < 5) { 1523 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1524 goto bad; 1525 } 1526 if (off > optlen - (int)sizeof(int32_t)) { 1527 cp[IPOPT_OFFSET + 1] += (1 << 4); 1528 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1529 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1530 goto bad; 1531 } 1532 break; 1533 } 1534 off--; /* 0 origin */ 1535 sin = (struct in_addr *)(cp + off); 1536 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1537 1538 case IPOPT_TS_TSONLY: 1539 break; 1540 1541 case IPOPT_TS_TSANDADDR: 1542 if (off + sizeof(n_time) + 1543 sizeof(struct in_addr) > optlen) { 1544 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1545 goto bad; 1546 } 1547 ipaddr.sin_addr = dst; 1548 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1549 m->m_pkthdr.rcvif); 1550 if (ia == NULL) 1551 continue; 1552 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1553 sizeof(struct in_addr)); 1554 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1555 off += sizeof(struct in_addr); 1556 break; 1557 1558 case IPOPT_TS_PRESPEC: 1559 if (off + sizeof(n_time) + 1560 sizeof(struct in_addr) > optlen) { 1561 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1562 goto bad; 1563 } 1564 (void)memcpy(&ipaddr.sin_addr, sin, 1565 sizeof(struct in_addr)); 1566 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1567 continue; 1568 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1569 off += sizeof(struct in_addr); 1570 break; 1571 1572 default: 1573 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1574 goto bad; 1575 } 1576 ntime = iptime(); 1577 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1578 cp[IPOPT_OFFSET] += sizeof(n_time); 1579 } 1580 } 1581 if (forward && ipforwarding) { 1582 ip_forward(m, 1); 1583 return (1); 1584 } 1585 return (0); 1586 bad: 1587 icmp_error(m, type, code, 0, 0); 1588 ipstat.ips_badoptions++; 1589 return (1); 1590 } 1591 1592 /* 1593 * Given address of next destination (final or next hop), 1594 * return internet address info of interface to be used to get there. 1595 */ 1596 struct in_ifaddr * 1597 ip_rtaddr(dst) 1598 struct in_addr dst; 1599 { 1600 struct route sro; 1601 struct sockaddr_in *sin; 1602 struct in_ifaddr *ifa; 1603 1604 bzero(&sro, sizeof(sro)); 1605 sin = (struct sockaddr_in *)&sro.ro_dst; 1606 sin->sin_family = AF_INET; 1607 sin->sin_len = sizeof(*sin); 1608 sin->sin_addr = dst; 1609 rtalloc_ign(&sro, RTF_CLONING); 1610 1611 if (sro.ro_rt == NULL) 1612 return (NULL); 1613 1614 ifa = ifatoia(sro.ro_rt->rt_ifa); 1615 RTFREE(sro.ro_rt); 1616 return (ifa); 1617 } 1618 1619 /* 1620 * Save incoming source route for use in replies, 1621 * to be picked up later by ip_srcroute if the receiver is interested. 1622 */ 1623 static void 1624 save_rte(m, option, dst) 1625 struct mbuf *m; 1626 u_char *option; 1627 struct in_addr dst; 1628 { 1629 unsigned olen; 1630 struct ipopt_tag *opts; 1631 1632 opts = (struct ipopt_tag *)m_tag_get(PACKET_TAG_IPOPTIONS, 1633 sizeof(struct ipopt_tag), M_NOWAIT); 1634 if (opts == NULL) 1635 return; 1636 1637 olen = option[IPOPT_OLEN]; 1638 #ifdef DIAGNOSTIC 1639 if (ipprintfs) 1640 printf("save_rte: olen %d\n", olen); 1641 #endif 1642 if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) { 1643 m_tag_free((struct m_tag *)opts); 1644 return; 1645 } 1646 bcopy(option, opts->ip_srcrt.srcopt, olen); 1647 opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1648 opts->ip_srcrt.dst = dst; 1649 m_tag_prepend(m, (struct m_tag *)opts); 1650 } 1651 1652 /* 1653 * Retrieve incoming source route for use in replies, 1654 * in the same form used by setsockopt. 1655 * The first hop is placed before the options, will be removed later. 1656 */ 1657 struct mbuf * 1658 ip_srcroute(m0) 1659 struct mbuf *m0; 1660 { 1661 register struct in_addr *p, *q; 1662 register struct mbuf *m; 1663 struct ipopt_tag *opts; 1664 1665 opts = (struct ipopt_tag *)m_tag_find(m0, PACKET_TAG_IPOPTIONS, NULL); 1666 if (opts == NULL) 1667 return (NULL); 1668 1669 if (opts->ip_nhops == 0) 1670 return (NULL); 1671 m = m_get(M_DONTWAIT, MT_DATA); 1672 if (m == NULL) 1673 return (NULL); 1674 1675 #define OPTSIZ (sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt)) 1676 1677 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1678 m->m_len = opts->ip_nhops * sizeof(struct in_addr) + 1679 sizeof(struct in_addr) + OPTSIZ; 1680 #ifdef DIAGNOSTIC 1681 if (ipprintfs) 1682 printf("ip_srcroute: nhops %d mlen %d", opts->ip_nhops, m->m_len); 1683 #endif 1684 1685 /* 1686 * First save first hop for return route 1687 */ 1688 p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]); 1689 *(mtod(m, struct in_addr *)) = *p--; 1690 #ifdef DIAGNOSTIC 1691 if (ipprintfs) 1692 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1693 #endif 1694 1695 /* 1696 * Copy option fields and padding (nop) to mbuf. 1697 */ 1698 opts->ip_srcrt.nop = IPOPT_NOP; 1699 opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1700 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1701 &(opts->ip_srcrt.nop), OPTSIZ); 1702 q = (struct in_addr *)(mtod(m, caddr_t) + 1703 sizeof(struct in_addr) + OPTSIZ); 1704 #undef OPTSIZ 1705 /* 1706 * Record return path as an IP source route, 1707 * reversing the path (pointers are now aligned). 1708 */ 1709 while (p >= opts->ip_srcrt.route) { 1710 #ifdef DIAGNOSTIC 1711 if (ipprintfs) 1712 printf(" %lx", (u_long)ntohl(q->s_addr)); 1713 #endif 1714 *q++ = *p--; 1715 } 1716 /* 1717 * Last hop goes to final destination. 1718 */ 1719 *q = opts->ip_srcrt.dst; 1720 #ifdef DIAGNOSTIC 1721 if (ipprintfs) 1722 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1723 #endif 1724 m_tag_delete(m0, (struct m_tag *)opts); 1725 return (m); 1726 } 1727 1728 /* 1729 * Strip out IP options, at higher 1730 * level protocol in the kernel. 1731 * Second argument is buffer to which options 1732 * will be moved, and return value is their length. 1733 * XXX should be deleted; last arg currently ignored. 1734 */ 1735 void 1736 ip_stripoptions(m, mopt) 1737 register struct mbuf *m; 1738 struct mbuf *mopt; 1739 { 1740 register int i; 1741 struct ip *ip = mtod(m, struct ip *); 1742 register caddr_t opts; 1743 int olen; 1744 1745 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1746 opts = (caddr_t)(ip + 1); 1747 i = m->m_len - (sizeof (struct ip) + olen); 1748 bcopy(opts + olen, opts, (unsigned)i); 1749 m->m_len -= olen; 1750 if (m->m_flags & M_PKTHDR) 1751 m->m_pkthdr.len -= olen; 1752 ip->ip_v = IPVERSION; 1753 ip->ip_hl = sizeof(struct ip) >> 2; 1754 } 1755 1756 u_char inetctlerrmap[PRC_NCMDS] = { 1757 0, 0, 0, 0, 1758 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1759 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1760 EMSGSIZE, EHOSTUNREACH, 0, 0, 1761 0, 0, EHOSTUNREACH, 0, 1762 ENOPROTOOPT, ECONNREFUSED 1763 }; 1764 1765 /* 1766 * Forward a packet. If some error occurs return the sender 1767 * an icmp packet. Note we can't always generate a meaningful 1768 * icmp message because icmp doesn't have a large enough repertoire 1769 * of codes and types. 1770 * 1771 * If not forwarding, just drop the packet. This could be confusing 1772 * if ipforwarding was zero but some routing protocol was advancing 1773 * us as a gateway to somewhere. However, we must let the routing 1774 * protocol deal with that. 1775 * 1776 * The srcrt parameter indicates whether the packet is being forwarded 1777 * via a source route. 1778 */ 1779 void 1780 ip_forward(struct mbuf *m, int srcrt) 1781 { 1782 struct ip *ip = mtod(m, struct ip *); 1783 struct in_ifaddr *ia = NULL; 1784 struct mbuf *mcopy; 1785 struct in_addr dest; 1786 int error, type = 0, code = 0, mtu = 0; 1787 1788 #ifdef DIAGNOSTIC 1789 if (ipprintfs) 1790 printf("forward: src %lx dst %lx ttl %x\n", 1791 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1792 ip->ip_ttl); 1793 #endif 1794 1795 1796 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1797 ipstat.ips_cantforward++; 1798 m_freem(m); 1799 return; 1800 } 1801 #ifdef IPSTEALTH 1802 if (!ipstealth) { 1803 #endif 1804 if (ip->ip_ttl <= IPTTLDEC) { 1805 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1806 0, 0); 1807 return; 1808 } 1809 #ifdef IPSTEALTH 1810 } 1811 #endif 1812 1813 if (!srcrt && (ia = ip_rtaddr(ip->ip_dst)) == NULL) { 1814 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1815 return; 1816 } 1817 1818 /* 1819 * Save the IP header and at most 8 bytes of the payload, 1820 * in case we need to generate an ICMP message to the src. 1821 * 1822 * XXX this can be optimized a lot by saving the data in a local 1823 * buffer on the stack (72 bytes at most), and only allocating the 1824 * mbuf if really necessary. The vast majority of the packets 1825 * are forwarded without having to send an ICMP back (either 1826 * because unnecessary, or because rate limited), so we are 1827 * really we are wasting a lot of work here. 1828 * 1829 * We don't use m_copy() because it might return a reference 1830 * to a shared cluster. Both this function and ip_output() 1831 * assume exclusive access to the IP header in `m', so any 1832 * data in a cluster may change before we reach icmp_error(). 1833 */ 1834 MGET(mcopy, M_DONTWAIT, m->m_type); 1835 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1836 /* 1837 * It's probably ok if the pkthdr dup fails (because 1838 * the deep copy of the tag chain failed), but for now 1839 * be conservative and just discard the copy since 1840 * code below may some day want the tags. 1841 */ 1842 m_free(mcopy); 1843 mcopy = NULL; 1844 } 1845 if (mcopy != NULL) { 1846 mcopy->m_len = imin((ip->ip_hl << 2) + 8, 1847 (int)ip->ip_len); 1848 mcopy->m_pkthdr.len = mcopy->m_len; 1849 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1850 } 1851 1852 #ifdef IPSTEALTH 1853 if (!ipstealth) { 1854 #endif 1855 ip->ip_ttl -= IPTTLDEC; 1856 #ifdef IPSTEALTH 1857 } 1858 #endif 1859 1860 /* 1861 * If forwarding packet using same interface that it came in on, 1862 * perhaps should send a redirect to sender to shortcut a hop. 1863 * Only send redirect if source is sending directly to us, 1864 * and if packet was not source routed (or has any options). 1865 * Also, don't send redirect if forwarding using a default route 1866 * or a route modified by a redirect. 1867 */ 1868 dest.s_addr = 0; 1869 if (!srcrt && ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1870 struct sockaddr_in *sin; 1871 struct route ro; 1872 struct rtentry *rt; 1873 1874 bzero(&ro, sizeof(ro)); 1875 sin = (struct sockaddr_in *)&ro.ro_dst; 1876 sin->sin_family = AF_INET; 1877 sin->sin_len = sizeof(*sin); 1878 sin->sin_addr = ip->ip_dst; 1879 rtalloc_ign(&ro, RTF_CLONING); 1880 1881 rt = ro.ro_rt; 1882 1883 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1884 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1885 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1886 u_long src = ntohl(ip->ip_src.s_addr); 1887 1888 if (RTA(rt) && 1889 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1890 if (rt->rt_flags & RTF_GATEWAY) 1891 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1892 else 1893 dest.s_addr = ip->ip_dst.s_addr; 1894 /* Router requirements says to only send host redirects */ 1895 type = ICMP_REDIRECT; 1896 code = ICMP_REDIRECT_HOST; 1897 #ifdef DIAGNOSTIC 1898 if (ipprintfs) 1899 printf("redirect (%d) to %lx\n", code, (u_long)dest.s_addr); 1900 #endif 1901 } 1902 } 1903 if (rt) 1904 RTFREE(rt); 1905 } 1906 1907 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 1908 if (error) 1909 ipstat.ips_cantforward++; 1910 else { 1911 ipstat.ips_forward++; 1912 if (type) 1913 ipstat.ips_redirectsent++; 1914 else { 1915 if (mcopy) 1916 m_freem(mcopy); 1917 return; 1918 } 1919 } 1920 if (mcopy == NULL) 1921 return; 1922 1923 switch (error) { 1924 1925 case 0: /* forwarded, but need redirect */ 1926 /* type, code set above */ 1927 break; 1928 1929 case ENETUNREACH: /* shouldn't happen, checked above */ 1930 case EHOSTUNREACH: 1931 case ENETDOWN: 1932 case EHOSTDOWN: 1933 default: 1934 type = ICMP_UNREACH; 1935 code = ICMP_UNREACH_HOST; 1936 break; 1937 1938 case EMSGSIZE: 1939 type = ICMP_UNREACH; 1940 code = ICMP_UNREACH_NEEDFRAG; 1941 #if defined(IPSEC) || defined(FAST_IPSEC) 1942 /* 1943 * If the packet is routed over IPsec tunnel, tell the 1944 * originator the tunnel MTU. 1945 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1946 * XXX quickhack!!! 1947 */ 1948 { 1949 struct secpolicy *sp = NULL; 1950 int ipsecerror; 1951 int ipsechdr; 1952 struct route *ro; 1953 1954 #ifdef IPSEC 1955 sp = ipsec4_getpolicybyaddr(mcopy, 1956 IPSEC_DIR_OUTBOUND, 1957 IP_FORWARDING, 1958 &ipsecerror); 1959 #else /* FAST_IPSEC */ 1960 sp = ipsec_getpolicybyaddr(mcopy, 1961 IPSEC_DIR_OUTBOUND, 1962 IP_FORWARDING, 1963 &ipsecerror); 1964 #endif 1965 if (sp != NULL) { 1966 /* count IPsec header size */ 1967 ipsechdr = ipsec4_hdrsiz(mcopy, 1968 IPSEC_DIR_OUTBOUND, 1969 NULL); 1970 1971 /* 1972 * find the correct route for outer IPv4 1973 * header, compute tunnel MTU. 1974 */ 1975 if (sp->req != NULL 1976 && sp->req->sav != NULL 1977 && sp->req->sav->sah != NULL) { 1978 ro = &sp->req->sav->sah->sa_route; 1979 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1980 mtu = 1981 ro->ro_rt->rt_rmx.rmx_mtu ? 1982 ro->ro_rt->rt_rmx.rmx_mtu : 1983 ro->ro_rt->rt_ifp->if_mtu; 1984 mtu -= ipsechdr; 1985 } 1986 } 1987 1988 #ifdef IPSEC 1989 key_freesp(sp); 1990 #else /* FAST_IPSEC */ 1991 KEY_FREESP(&sp); 1992 #endif 1993 ipstat.ips_cantfrag++; 1994 break; 1995 } 1996 } 1997 #endif /*IPSEC || FAST_IPSEC*/ 1998 /* 1999 * If the MTU wasn't set before use the interface mtu or 2000 * fall back to the next smaller mtu step compared to the 2001 * current packet size. 2002 */ 2003 if (mtu == 0) { 2004 if (ia != NULL) 2005 mtu = ia->ia_ifp->if_mtu; 2006 else 2007 mtu = ip_next_mtu(ip->ip_len, 0); 2008 } 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.s_addr, mtu); 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_BINTIME | SO_TIMESTAMP)) { 2045 struct bintime bt; 2046 2047 bintime(&bt); 2048 if (inp->inp_socket->so_options & SO_BINTIME) { 2049 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 2050 SCM_BINTIME, SOL_SOCKET); 2051 if (*mp) 2052 mp = &(*mp)->m_next; 2053 } 2054 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2055 struct timeval tv; 2056 2057 bintime2timeval(&bt, &tv); 2058 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2059 SCM_TIMESTAMP, SOL_SOCKET); 2060 if (*mp) 2061 mp = &(*mp)->m_next; 2062 } 2063 } 2064 if (inp->inp_flags & INP_RECVDSTADDR) { 2065 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2066 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2067 if (*mp) 2068 mp = &(*mp)->m_next; 2069 } 2070 if (inp->inp_flags & INP_RECVTTL) { 2071 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2072 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2073 if (*mp) 2074 mp = &(*mp)->m_next; 2075 } 2076 #ifdef notyet 2077 /* XXX 2078 * Moving these out of udp_input() made them even more broken 2079 * than they already were. 2080 */ 2081 /* options were tossed already */ 2082 if (inp->inp_flags & INP_RECVOPTS) { 2083 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2084 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2085 if (*mp) 2086 mp = &(*mp)->m_next; 2087 } 2088 /* ip_srcroute doesn't do what we want here, need to fix */ 2089 if (inp->inp_flags & INP_RECVRETOPTS) { 2090 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 2091 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2092 if (*mp) 2093 mp = &(*mp)->m_next; 2094 } 2095 #endif 2096 if (inp->inp_flags & INP_RECVIF) { 2097 struct ifnet *ifp; 2098 struct sdlbuf { 2099 struct sockaddr_dl sdl; 2100 u_char pad[32]; 2101 } sdlbuf; 2102 struct sockaddr_dl *sdp; 2103 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2104 2105 if (((ifp = m->m_pkthdr.rcvif)) 2106 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2107 sdp = (struct sockaddr_dl *) 2108 (ifaddr_byindex(ifp->if_index)->ifa_addr); 2109 /* 2110 * Change our mind and don't try copy. 2111 */ 2112 if ((sdp->sdl_family != AF_LINK) 2113 || (sdp->sdl_len > sizeof(sdlbuf))) { 2114 goto makedummy; 2115 } 2116 bcopy(sdp, sdl2, sdp->sdl_len); 2117 } else { 2118 makedummy: 2119 sdl2->sdl_len 2120 = offsetof(struct sockaddr_dl, sdl_data[0]); 2121 sdl2->sdl_family = AF_LINK; 2122 sdl2->sdl_index = 0; 2123 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2124 } 2125 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2126 IP_RECVIF, IPPROTO_IP); 2127 if (*mp) 2128 mp = &(*mp)->m_next; 2129 } 2130 } 2131 2132 /* 2133 * XXX these routines are called from the upper part of the kernel. 2134 * They need to be locked when we remove Giant. 2135 * 2136 * They could also be moved to ip_mroute.c, since all the RSVP 2137 * handling is done there already. 2138 */ 2139 static int ip_rsvp_on; 2140 struct socket *ip_rsvpd; 2141 int 2142 ip_rsvp_init(struct socket *so) 2143 { 2144 if (so->so_type != SOCK_RAW || 2145 so->so_proto->pr_protocol != IPPROTO_RSVP) 2146 return EOPNOTSUPP; 2147 2148 if (ip_rsvpd != NULL) 2149 return EADDRINUSE; 2150 2151 ip_rsvpd = so; 2152 /* 2153 * This may seem silly, but we need to be sure we don't over-increment 2154 * the RSVP counter, in case something slips up. 2155 */ 2156 if (!ip_rsvp_on) { 2157 ip_rsvp_on = 1; 2158 rsvp_on++; 2159 } 2160 2161 return 0; 2162 } 2163 2164 int 2165 ip_rsvp_done(void) 2166 { 2167 ip_rsvpd = NULL; 2168 /* 2169 * This may seem silly, but we need to be sure we don't over-decrement 2170 * the RSVP counter, in case something slips up. 2171 */ 2172 if (ip_rsvp_on) { 2173 ip_rsvp_on = 0; 2174 rsvp_on--; 2175 } 2176 return 0; 2177 } 2178 2179 void 2180 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 2181 { 2182 if (rsvp_input_p) { /* call the real one if loaded */ 2183 rsvp_input_p(m, off); 2184 return; 2185 } 2186 2187 /* Can still get packets with rsvp_on = 0 if there is a local member 2188 * of the group to which the RSVP packet is addressed. But in this 2189 * case we want to throw the packet away. 2190 */ 2191 2192 if (!rsvp_on) { 2193 m_freem(m); 2194 return; 2195 } 2196 2197 if (ip_rsvpd != NULL) { 2198 rip_input(m, off); 2199 return; 2200 } 2201 /* Drop the packet */ 2202 m_freem(m); 2203 }
Cache object: df6405586f07540f614ab925b3b7c0bc
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