Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
FreeBSD/Linux Kernel Cross Reference
sys/netinet/ip_input.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
SearchContext: - none - 3 - 10
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 * $FreeBSD$ 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 static void ipq_zone_change(void *); 194 195 static int maxnipq; /* Administrative limit on # reass queues. */ 196 static int nipq = 0; /* Total # of reass queues */ 197 SYSCTL_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, &nipq, 0, 198 "Current number of IPv4 fragment reassembly queue entries"); 199 200 static int maxfragsperpacket; 201 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 202 &maxfragsperpacket, 0, 203 "Maximum number of IPv4 fragments allowed per packet"); 204 205 struct callout ipport_tick_callout; 206 207 #ifdef IPCTL_DEFMTU 208 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 209 &ip_mtu, 0, "Default MTU"); 210 #endif 211 212 #ifdef IPSTEALTH 213 int ipstealth = 0; 214 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 215 &ipstealth, 0, ""); 216 #endif 217 218 /* 219 * ipfw_ether and ipfw_bridge hooks. 220 * XXX: Temporary until those are converted to pfil_hooks as well. 221 */ 222 ip_fw_chk_t *ip_fw_chk_ptr = NULL; 223 ip_dn_io_t *ip_dn_io_ptr = NULL; 224 int fw_enable = 1; 225 int fw_one_pass = 1; 226 227 /* 228 * XXX this is ugly. IP options source routing magic. 229 */ 230 struct ipoptrt { 231 struct in_addr dst; /* final destination */ 232 char nop; /* one NOP to align */ 233 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 234 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 235 }; 236 237 struct ipopt_tag { 238 struct m_tag tag; 239 int ip_nhops; 240 struct ipoptrt ip_srcrt; 241 }; 242 243 static void save_rte(struct mbuf *, u_char *, struct in_addr); 244 static int ip_dooptions(struct mbuf *m, int); 245 static void ip_forward(struct mbuf *m, int srcrt); 246 static void ip_freef(struct ipqhead *, struct ipq *); 247 248 /* 249 * IP initialization: fill in IP protocol switch table. 250 * All protocols not implemented in kernel go to raw IP protocol handler. 251 */ 252 void 253 ip_init() 254 { 255 register struct protosw *pr; 256 register int i; 257 258 TAILQ_INIT(&in_ifaddrhead); 259 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 260 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 261 if (pr == NULL) 262 panic("ip_init: PF_INET not found"); 263 264 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 265 for (i = 0; i < IPPROTO_MAX; i++) 266 ip_protox[i] = pr - inetsw; 267 /* 268 * Cycle through IP protocols and put them into the appropriate place 269 * in ip_protox[]. 270 */ 271 for (pr = inetdomain.dom_protosw; 272 pr < inetdomain.dom_protoswNPROTOSW; pr++) 273 if (pr->pr_domain->dom_family == PF_INET && 274 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 275 /* Be careful to only index valid IP protocols. */ 276 if (pr->pr_protocol < IPPROTO_MAX) 277 ip_protox[pr->pr_protocol] = pr - inetsw; 278 } 279 280 /* Initialize packet filter hooks. */ 281 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 282 inet_pfil_hook.ph_af = AF_INET; 283 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 284 printf("%s: WARNING: unable to register pfil hook, " 285 "error %d\n", __func__, i); 286 287 /* Initialize IP reassembly queue. */ 288 IPQ_LOCK_INIT(); 289 for (i = 0; i < IPREASS_NHASH; i++) 290 TAILQ_INIT(&ipq[i]); 291 maxnipq = nmbclusters / 32; 292 maxfragsperpacket = 16; 293 ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 294 NULL, UMA_ALIGN_PTR, 0); 295 maxnipq_update(); 296 297 /* Start ipport_tick. */ 298 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE); 299 ipport_tick(NULL); 300 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL, 301 SHUTDOWN_PRI_DEFAULT); 302 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, 303 NULL, EVENTHANDLER_PRI_ANY); 304 305 /* Initialize various other remaining things. */ 306 ip_id = time_second & 0xffff; 307 ipintrq.ifq_maxlen = ipqmaxlen; 308 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 309 netisr_register(NETISR_IP, ip_input, &ipintrq, NETISR_MPSAFE); 310 } 311 312 void ip_fini(xtp) 313 void *xtp; 314 { 315 callout_stop(&ipport_tick_callout); 316 } 317 318 /* 319 * Ip input routine. Checksum and byte swap header. If fragmented 320 * try to reassemble. Process options. Pass to next level. 321 */ 322 void 323 ip_input(struct mbuf *m) 324 { 325 struct ip *ip = NULL; 326 struct in_ifaddr *ia = NULL; 327 struct ifaddr *ifa; 328 int checkif, hlen = 0; 329 u_short sum; 330 int dchg = 0; /* dest changed after fw */ 331 struct in_addr odst; /* original dst address */ 332 #ifdef FAST_IPSEC 333 struct m_tag *mtag; 334 struct tdb_ident *tdbi; 335 struct secpolicy *sp; 336 int s, error; 337 #endif /* FAST_IPSEC */ 338 339 M_ASSERTPKTHDR(m); 340 341 if (m->m_flags & M_FASTFWD_OURS) { 342 /* 343 * Firewall or NAT changed destination to local. 344 * We expect ip_len and ip_off to be in host byte order. 345 */ 346 m->m_flags &= ~M_FASTFWD_OURS; 347 /* Set up some basics that will be used later. */ 348 ip = mtod(m, struct ip *); 349 hlen = ip->ip_hl << 2; 350 goto ours; 351 } 352 353 ipstat.ips_total++; 354 355 if (m->m_pkthdr.len < sizeof(struct ip)) 356 goto tooshort; 357 358 if (m->m_len < sizeof (struct ip) && 359 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 360 ipstat.ips_toosmall++; 361 return; 362 } 363 ip = mtod(m, struct ip *); 364 365 if (ip->ip_v != IPVERSION) { 366 ipstat.ips_badvers++; 367 goto bad; 368 } 369 370 hlen = ip->ip_hl << 2; 371 if (hlen < sizeof(struct ip)) { /* minimum header length */ 372 ipstat.ips_badhlen++; 373 goto bad; 374 } 375 if (hlen > m->m_len) { 376 if ((m = m_pullup(m, hlen)) == NULL) { 377 ipstat.ips_badhlen++; 378 return; 379 } 380 ip = mtod(m, struct ip *); 381 } 382 383 /* 127/8 must not appear on wire - RFC1122 */ 384 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 385 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 386 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 387 ipstat.ips_badaddr++; 388 goto bad; 389 } 390 } 391 392 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 393 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 394 } else { 395 if (hlen == sizeof(struct ip)) { 396 sum = in_cksum_hdr(ip); 397 } else { 398 sum = in_cksum(m, hlen); 399 } 400 } 401 if (sum) { 402 ipstat.ips_badsum++; 403 goto bad; 404 } 405 406 #ifdef ALTQ 407 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 408 /* packet is dropped by traffic conditioner */ 409 return; 410 #endif 411 412 /* 413 * Convert fields to host representation. 414 */ 415 ip->ip_len = ntohs(ip->ip_len); 416 if (ip->ip_len < hlen) { 417 ipstat.ips_badlen++; 418 goto bad; 419 } 420 ip->ip_off = ntohs(ip->ip_off); 421 422 /* 423 * Check that the amount of data in the buffers 424 * is as at least much as the IP header would have us expect. 425 * Trim mbufs if longer than we expect. 426 * Drop packet if shorter than we expect. 427 */ 428 if (m->m_pkthdr.len < ip->ip_len) { 429 tooshort: 430 ipstat.ips_tooshort++; 431 goto bad; 432 } 433 if (m->m_pkthdr.len > ip->ip_len) { 434 if (m->m_len == m->m_pkthdr.len) { 435 m->m_len = ip->ip_len; 436 m->m_pkthdr.len = ip->ip_len; 437 } else 438 m_adj(m, ip->ip_len - m->m_pkthdr.len); 439 } 440 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 441 /* 442 * Bypass packet filtering for packets from a tunnel (gif). 443 */ 444 if (ipsec_getnhist(m)) 445 goto passin; 446 #endif 447 #if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF) 448 /* 449 * Bypass packet filtering for packets from a tunnel (gif). 450 */ 451 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 452 goto passin; 453 #endif 454 455 /* 456 * Run through list of hooks for input packets. 457 * 458 * NB: Beware of the destination address changing (e.g. 459 * by NAT rewriting). When this happens, tell 460 * ip_forward to do the right thing. 461 */ 462 463 /* Jump over all PFIL processing if hooks are not active. */ 464 if (inet_pfil_hook.ph_busy_count == -1) 465 goto passin; 466 467 odst = ip->ip_dst; 468 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 469 PFIL_IN, NULL) != 0) 470 return; 471 if (m == NULL) /* consumed by filter */ 472 return; 473 474 ip = mtod(m, struct ip *); 475 dchg = (odst.s_addr != ip->ip_dst.s_addr); 476 477 #ifdef IPFIREWALL_FORWARD 478 if (m->m_flags & M_FASTFWD_OURS) { 479 m->m_flags &= ~M_FASTFWD_OURS; 480 goto ours; 481 } 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 */ 492 493 passin: 494 /* 495 * Process options and, if not destined for us, 496 * ship it on. ip_dooptions returns 1 when an 497 * error was detected (causing an icmp message 498 * to be sent and the original packet to be freed). 499 */ 500 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 501 return; 502 503 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 504 * matter if it is destined to another node, or whether it is 505 * a multicast one, RSVP wants it! and prevents it from being forwarded 506 * anywhere else. Also checks if the rsvp daemon is running before 507 * grabbing the packet. 508 */ 509 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 510 goto ours; 511 512 /* 513 * Check our list of addresses, to see if the packet is for us. 514 * If we don't have any addresses, assume any unicast packet 515 * we receive might be for us (and let the upper layers deal 516 * with it). 517 */ 518 if (TAILQ_EMPTY(&in_ifaddrhead) && 519 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 520 goto ours; 521 522 /* 523 * Enable a consistency check between the destination address 524 * and the arrival interface for a unicast packet (the RFC 1122 525 * strong ES model) if IP forwarding is disabled and the packet 526 * is not locally generated and the packet is not subject to 527 * 'ipfw fwd'. 528 * 529 * XXX - Checking also should be disabled if the destination 530 * address is ipnat'ed to a different interface. 531 * 532 * XXX - Checking is incompatible with IP aliases added 533 * to the loopback interface instead of the interface where 534 * the packets are received. 535 * 536 * XXX - This is the case for carp vhost IPs as well so we 537 * insert a workaround. If the packet got here, we already 538 * checked with carp_iamatch() and carp_forus(). 539 */ 540 checkif = ip_checkinterface && (ipforwarding == 0) && 541 m->m_pkthdr.rcvif != NULL && 542 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 543 #ifdef DEV_CARP 544 !m->m_pkthdr.rcvif->if_carp && 545 #endif 546 (dchg == 0); 547 548 /* 549 * Check for exact addresses in the hash bucket. 550 */ 551 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 552 /* 553 * If the address matches, verify that the packet 554 * arrived via the correct interface if checking is 555 * enabled. 556 */ 557 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 558 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 559 goto ours; 560 } 561 /* 562 * Check for broadcast addresses. 563 * 564 * Only accept broadcast packets that arrive via the matching 565 * interface. Reception of forwarded directed broadcasts would 566 * be handled via ip_forward() and ether_output() with the loopback 567 * into the stack for SIMPLEX interfaces handled by ether_output(). 568 */ 569 if (m->m_pkthdr.rcvif != NULL && 570 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 571 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 572 if (ifa->ifa_addr->sa_family != AF_INET) 573 continue; 574 ia = ifatoia(ifa); 575 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 576 ip->ip_dst.s_addr) 577 goto ours; 578 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 579 goto ours; 580 #ifdef BOOTP_COMPAT 581 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 582 goto ours; 583 #endif 584 } 585 } 586 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */ 587 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) { 588 ipstat.ips_cantforward++; 589 m_freem(m); 590 return; 591 } 592 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 593 struct in_multi *inm; 594 if (ip_mrouter) { 595 /* 596 * If we are acting as a multicast router, all 597 * incoming multicast packets are passed to the 598 * kernel-level multicast forwarding function. 599 * The packet is returned (relatively) intact; if 600 * ip_mforward() returns a non-zero value, the packet 601 * must be discarded, else it may be accepted below. 602 */ 603 if (ip_mforward && 604 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 605 ipstat.ips_cantforward++; 606 m_freem(m); 607 return; 608 } 609 610 /* 611 * The process-level routing daemon needs to receive 612 * all multicast IGMP packets, whether or not this 613 * host belongs to their destination groups. 614 */ 615 if (ip->ip_p == IPPROTO_IGMP) 616 goto ours; 617 ipstat.ips_forward++; 618 } 619 /* 620 * See if we belong to the destination multicast group on the 621 * arrival interface. 622 */ 623 IN_MULTI_LOCK(); 624 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 625 IN_MULTI_UNLOCK(); 626 if (inm == NULL) { 627 ipstat.ips_notmember++; 628 m_freem(m); 629 return; 630 } 631 goto ours; 632 } 633 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 634 goto ours; 635 if (ip->ip_dst.s_addr == INADDR_ANY) 636 goto ours; 637 638 /* 639 * FAITH(Firewall Aided Internet Translator) 640 */ 641 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 642 if (ip_keepfaith) { 643 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 644 goto ours; 645 } 646 m_freem(m); 647 return; 648 } 649 650 /* 651 * Not for us; forward if possible and desirable. 652 */ 653 if (ipforwarding == 0) { 654 ipstat.ips_cantforward++; 655 m_freem(m); 656 } else { 657 #ifdef IPSEC 658 /* 659 * Enforce inbound IPsec SPD. 660 */ 661 if (ipsec4_in_reject(m, NULL)) { 662 ipsecstat.in_polvio++; 663 goto bad; 664 } 665 #endif /* IPSEC */ 666 #ifdef FAST_IPSEC 667 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 668 s = splnet(); 669 if (mtag != NULL) { 670 tdbi = (struct tdb_ident *)(mtag + 1); 671 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 672 } else { 673 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 674 IP_FORWARDING, &error); 675 } 676 if (sp == NULL) { /* NB: can happen if error */ 677 splx(s); 678 /*XXX error stat???*/ 679 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 680 goto bad; 681 } 682 683 /* 684 * Check security policy against packet attributes. 685 */ 686 error = ipsec_in_reject(sp, m); 687 KEY_FREESP(&sp); 688 splx(s); 689 if (error) { 690 ipstat.ips_cantforward++; 691 goto bad; 692 } 693 #endif /* FAST_IPSEC */ 694 ip_forward(m, dchg); 695 } 696 return; 697 698 ours: 699 #ifdef IPSTEALTH 700 /* 701 * IPSTEALTH: Process non-routing options only 702 * if the packet is destined for us. 703 */ 704 if (ipstealth && hlen > sizeof (struct ip) && 705 ip_dooptions(m, 1)) 706 return; 707 #endif /* IPSTEALTH */ 708 709 /* Count the packet in the ip address stats */ 710 if (ia != NULL) { 711 ia->ia_ifa.if_ipackets++; 712 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 713 } 714 715 /* 716 * Attempt reassembly; if it succeeds, proceed. 717 * ip_reass() will return a different mbuf. 718 */ 719 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 720 m = ip_reass(m); 721 if (m == NULL) 722 return; 723 ip = mtod(m, struct ip *); 724 /* Get the header length of the reassembled packet */ 725 hlen = ip->ip_hl << 2; 726 } 727 728 /* 729 * Further protocols expect the packet length to be w/o the 730 * IP header. 731 */ 732 ip->ip_len -= hlen; 733 734 #ifdef IPSEC 735 /* 736 * enforce IPsec policy checking if we are seeing last header. 737 * note that we do not visit this with protocols with pcb layer 738 * code - like udp/tcp/raw ip. 739 */ 740 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 741 ipsec4_in_reject(m, NULL)) { 742 ipsecstat.in_polvio++; 743 goto bad; 744 } 745 #endif 746 #if FAST_IPSEC 747 /* 748 * enforce IPsec policy checking if we are seeing last header. 749 * note that we do not visit this with protocols with pcb layer 750 * code - like udp/tcp/raw ip. 751 */ 752 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 753 /* 754 * Check if the packet has already had IPsec processing 755 * done. If so, then just pass it along. This tag gets 756 * set during AH, ESP, etc. input handling, before the 757 * packet is returned to the ip input queue for delivery. 758 */ 759 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 760 s = splnet(); 761 if (mtag != NULL) { 762 tdbi = (struct tdb_ident *)(mtag + 1); 763 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 764 } else { 765 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 766 IP_FORWARDING, &error); 767 } 768 if (sp != NULL) { 769 /* 770 * Check security policy against packet attributes. 771 */ 772 error = ipsec_in_reject(sp, m); 773 KEY_FREESP(&sp); 774 } else { 775 /* XXX error stat??? */ 776 error = EINVAL; 777 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 778 goto bad; 779 } 780 splx(s); 781 if (error) 782 goto bad; 783 } 784 #endif /* FAST_IPSEC */ 785 786 /* 787 * Switch out to protocol's input routine. 788 */ 789 ipstat.ips_delivered++; 790 791 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 792 return; 793 bad: 794 m_freem(m); 795 } 796 797 /* 798 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 799 * max has slightly different semantics than the sysctl, for historical 800 * reasons. 801 */ 802 static void 803 maxnipq_update(void) 804 { 805 806 /* 807 * -1 for unlimited allocation. 808 */ 809 if (maxnipq < 0) 810 uma_zone_set_max(ipq_zone, 0); 811 /* 812 * Positive number for specific bound. 813 */ 814 if (maxnipq > 0) 815 uma_zone_set_max(ipq_zone, maxnipq); 816 /* 817 * Zero specifies no further fragment queue allocation -- set the 818 * bound very low, but rely on implementation elsewhere to actually 819 * prevent allocation and reclaim current queues. 820 */ 821 if (maxnipq == 0) 822 uma_zone_set_max(ipq_zone, 1); 823 } 824 825 static void 826 ipq_zone_change(void *tag) 827 { 828 829 if (maxnipq > 0 && maxnipq < (nmbclusters / 32)) { 830 maxnipq = nmbclusters / 32; 831 maxnipq_update(); 832 } 833 } 834 835 static int 836 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 837 { 838 int error, i; 839 840 i = maxnipq; 841 error = sysctl_handle_int(oidp, &i, 0, req); 842 if (error || !req->newptr) 843 return (error); 844 845 /* 846 * XXXRW: Might be a good idea to sanity check the argument and place 847 * an extreme upper bound. 848 */ 849 if (i < -1) 850 return (EINVAL); 851 maxnipq = i; 852 maxnipq_update(); 853 return (0); 854 } 855 856 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 857 NULL, 0, sysctl_maxnipq, "I", 858 "Maximum number of IPv4 fragment reassembly queue entries"); 859 860 /* 861 * Take incoming datagram fragment and try to reassemble it into 862 * whole datagram. If the argument is the first fragment or one 863 * in between the function will return NULL and store the mbuf 864 * in the fragment chain. If the argument is the last fragment 865 * the packet will be reassembled and the pointer to the new 866 * mbuf returned for further processing. Only m_tags attached 867 * to the first packet/fragment are preserved. 868 * The IP header is *NOT* adjusted out of iplen. 869 */ 870 871 struct mbuf * 872 ip_reass(struct mbuf *m) 873 { 874 struct ip *ip; 875 struct mbuf *p, *q, *nq, *t; 876 struct ipq *fp = NULL; 877 struct ipqhead *head; 878 int i, hlen, next; 879 u_int8_t ecn, ecn0; 880 u_short hash; 881 882 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 883 if (maxnipq == 0 || maxfragsperpacket == 0) { 884 ipstat.ips_fragments++; 885 ipstat.ips_fragdropped++; 886 m_freem(m); 887 return (NULL); 888 } 889 890 ip = mtod(m, struct ip *); 891 hlen = ip->ip_hl << 2; 892 893 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 894 head = &ipq[hash]; 895 IPQ_LOCK(); 896 897 /* 898 * Look for queue of fragments 899 * of this datagram. 900 */ 901 TAILQ_FOREACH(fp, head, ipq_list) 902 if (ip->ip_id == fp->ipq_id && 903 ip->ip_src.s_addr == fp->ipq_src.s_addr && 904 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 905 #ifdef MAC 906 mac_fragment_match(m, fp) && 907 #endif 908 ip->ip_p == fp->ipq_p) 909 goto found; 910 911 fp = NULL; 912 913 /* 914 * Attempt to trim the number of allocated fragment queues if it 915 * exceeds the administrative limit. 916 */ 917 if ((nipq > maxnipq) && (maxnipq > 0)) { 918 /* 919 * drop something from the tail of the current queue 920 * before proceeding further 921 */ 922 struct ipq *q = TAILQ_LAST(head, ipqhead); 923 if (q == NULL) { /* gak */ 924 for (i = 0; i < IPREASS_NHASH; i++) { 925 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 926 if (r) { 927 ipstat.ips_fragtimeout += r->ipq_nfrags; 928 ip_freef(&ipq[i], r); 929 break; 930 } 931 } 932 } else { 933 ipstat.ips_fragtimeout += q->ipq_nfrags; 934 ip_freef(head, q); 935 } 936 } 937 938 found: 939 /* 940 * Adjust ip_len to not reflect header, 941 * convert offset of this to bytes. 942 */ 943 ip->ip_len -= hlen; 944 if (ip->ip_off & IP_MF) { 945 /* 946 * Make sure that fragments have a data length 947 * that's a non-zero multiple of 8 bytes. 948 */ 949 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 950 ipstat.ips_toosmall++; /* XXX */ 951 goto dropfrag; 952 } 953 m->m_flags |= M_FRAG; 954 } else 955 m->m_flags &= ~M_FRAG; 956 ip->ip_off <<= 3; 957 958 959 /* 960 * Attempt reassembly; if it succeeds, proceed. 961 * ip_reass() will return a different mbuf. 962 */ 963 ipstat.ips_fragments++; 964 m->m_pkthdr.header = ip; 965 966 /* Previous ip_reass() started here. */ 967 /* 968 * Presence of header sizes in mbufs 969 * would confuse code below. 970 */ 971 m->m_data += hlen; 972 m->m_len -= hlen; 973 974 /* 975 * If first fragment to arrive, create a reassembly queue. 976 */ 977 if (fp == NULL) { 978 fp = uma_zalloc(ipq_zone, M_NOWAIT); 979 if (fp == NULL) 980 goto dropfrag; 981 #ifdef MAC 982 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 983 uma_zfree(ipq_zone, fp); 984 fp = NULL; 985 goto dropfrag; 986 } 987 mac_create_ipq(m, fp); 988 #endif 989 TAILQ_INSERT_HEAD(head, fp, ipq_list); 990 nipq++; 991 fp->ipq_nfrags = 1; 992 fp->ipq_ttl = IPFRAGTTL; 993 fp->ipq_p = ip->ip_p; 994 fp->ipq_id = ip->ip_id; 995 fp->ipq_src = ip->ip_src; 996 fp->ipq_dst = ip->ip_dst; 997 fp->ipq_frags = m; 998 m->m_nextpkt = NULL; 999 goto done; 1000 } else { 1001 fp->ipq_nfrags++; 1002 #ifdef MAC 1003 mac_update_ipq(m, fp); 1004 #endif 1005 } 1006 1007 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1008 1009 /* 1010 * Handle ECN by comparing this segment with the first one; 1011 * if CE is set, do not lose CE. 1012 * drop if CE and not-ECT are mixed for the same packet. 1013 */ 1014 ecn = ip->ip_tos & IPTOS_ECN_MASK; 1015 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 1016 if (ecn == IPTOS_ECN_CE) { 1017 if (ecn0 == IPTOS_ECN_NOTECT) 1018 goto dropfrag; 1019 if (ecn0 != IPTOS_ECN_CE) 1020 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 1021 } 1022 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 1023 goto dropfrag; 1024 1025 /* 1026 * Find a segment which begins after this one does. 1027 */ 1028 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1029 if (GETIP(q)->ip_off > ip->ip_off) 1030 break; 1031 1032 /* 1033 * If there is a preceding segment, it may provide some of 1034 * our data already. If so, drop the data from the incoming 1035 * segment. If it provides all of our data, drop us, otherwise 1036 * stick new segment in the proper place. 1037 * 1038 * If some of the data is dropped from the the preceding 1039 * segment, then it's checksum is invalidated. 1040 */ 1041 if (p) { 1042 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1043 if (i > 0) { 1044 if (i >= ip->ip_len) 1045 goto dropfrag; 1046 m_adj(m, i); 1047 m->m_pkthdr.csum_flags = 0; 1048 ip->ip_off += i; 1049 ip->ip_len -= i; 1050 } 1051 m->m_nextpkt = p->m_nextpkt; 1052 p->m_nextpkt = m; 1053 } else { 1054 m->m_nextpkt = fp->ipq_frags; 1055 fp->ipq_frags = m; 1056 } 1057 1058 /* 1059 * While we overlap succeeding segments trim them or, 1060 * if they are completely covered, dequeue them. 1061 */ 1062 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1063 q = nq) { 1064 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1065 if (i < GETIP(q)->ip_len) { 1066 GETIP(q)->ip_len -= i; 1067 GETIP(q)->ip_off += i; 1068 m_adj(q, i); 1069 q->m_pkthdr.csum_flags = 0; 1070 break; 1071 } 1072 nq = q->m_nextpkt; 1073 m->m_nextpkt = nq; 1074 ipstat.ips_fragdropped++; 1075 fp->ipq_nfrags--; 1076 m_freem(q); 1077 } 1078 1079 /* 1080 * Check for complete reassembly and perform frag per packet 1081 * limiting. 1082 * 1083 * Frag limiting is performed here so that the nth frag has 1084 * a chance to complete the packet before we drop the packet. 1085 * As a result, n+1 frags are actually allowed per packet, but 1086 * only n will ever be stored. (n = maxfragsperpacket.) 1087 * 1088 */ 1089 next = 0; 1090 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1091 if (GETIP(q)->ip_off != next) { 1092 if (fp->ipq_nfrags > maxfragsperpacket) { 1093 ipstat.ips_fragdropped += fp->ipq_nfrags; 1094 ip_freef(head, fp); 1095 } 1096 goto done; 1097 } 1098 next += GETIP(q)->ip_len; 1099 } 1100 /* Make sure the last packet didn't have the IP_MF flag */ 1101 if (p->m_flags & M_FRAG) { 1102 if (fp->ipq_nfrags > maxfragsperpacket) { 1103 ipstat.ips_fragdropped += fp->ipq_nfrags; 1104 ip_freef(head, fp); 1105 } 1106 goto done; 1107 } 1108 1109 /* 1110 * Reassembly is complete. Make sure the packet is a sane size. 1111 */ 1112 q = fp->ipq_frags; 1113 ip = GETIP(q); 1114 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1115 ipstat.ips_toolong++; 1116 ipstat.ips_fragdropped += fp->ipq_nfrags; 1117 ip_freef(head, fp); 1118 goto done; 1119 } 1120 1121 /* 1122 * Concatenate fragments. 1123 */ 1124 m = q; 1125 t = m->m_next; 1126 m->m_next = NULL; 1127 m_cat(m, t); 1128 nq = q->m_nextpkt; 1129 q->m_nextpkt = NULL; 1130 for (q = nq; q != NULL; q = nq) { 1131 nq = q->m_nextpkt; 1132 q->m_nextpkt = NULL; 1133 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1134 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1135 m_cat(m, q); 1136 } 1137 /* 1138 * In order to do checksumming faster we do 'end-around carry' here 1139 * (and not in for{} loop), though it implies we are not going to 1140 * reassemble more than 64k fragments. 1141 */ 1142 m->m_pkthdr.csum_data = 1143 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1144 #ifdef MAC 1145 mac_create_datagram_from_ipq(fp, m); 1146 mac_destroy_ipq(fp); 1147 #endif 1148 1149 /* 1150 * Create header for new ip packet by modifying header of first 1151 * packet; dequeue and discard fragment reassembly header. 1152 * Make header visible. 1153 */ 1154 ip->ip_len = (ip->ip_hl << 2) + next; 1155 ip->ip_src = fp->ipq_src; 1156 ip->ip_dst = fp->ipq_dst; 1157 TAILQ_REMOVE(head, fp, ipq_list); 1158 nipq--; 1159 uma_zfree(ipq_zone, fp); 1160 m->m_len += (ip->ip_hl << 2); 1161 m->m_data -= (ip->ip_hl << 2); 1162 /* some debugging cruft by sklower, below, will go away soon */ 1163 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1164 m_fixhdr(m); 1165 ipstat.ips_reassembled++; 1166 IPQ_UNLOCK(); 1167 return (m); 1168 1169 dropfrag: 1170 ipstat.ips_fragdropped++; 1171 if (fp != NULL) 1172 fp->ipq_nfrags--; 1173 m_freem(m); 1174 done: 1175 IPQ_UNLOCK(); 1176 return (NULL); 1177 1178 #undef GETIP 1179 } 1180 1181 /* 1182 * Free a fragment reassembly header and all 1183 * associated datagrams. 1184 */ 1185 static void 1186 ip_freef(fhp, fp) 1187 struct ipqhead *fhp; 1188 struct ipq *fp; 1189 { 1190 register struct mbuf *q; 1191 1192 IPQ_LOCK_ASSERT(); 1193 1194 while (fp->ipq_frags) { 1195 q = fp->ipq_frags; 1196 fp->ipq_frags = q->m_nextpkt; 1197 m_freem(q); 1198 } 1199 TAILQ_REMOVE(fhp, fp, ipq_list); 1200 uma_zfree(ipq_zone, fp); 1201 nipq--; 1202 } 1203 1204 /* 1205 * IP timer processing; 1206 * if a timer expires on a reassembly 1207 * queue, discard it. 1208 */ 1209 void 1210 ip_slowtimo() 1211 { 1212 register struct ipq *fp; 1213 int i; 1214 1215 IPQ_LOCK(); 1216 for (i = 0; i < IPREASS_NHASH; i++) { 1217 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1218 struct ipq *fpp; 1219 1220 fpp = fp; 1221 fp = TAILQ_NEXT(fp, ipq_list); 1222 if(--fpp->ipq_ttl == 0) { 1223 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1224 ip_freef(&ipq[i], fpp); 1225 } 1226 } 1227 } 1228 /* 1229 * If we are over the maximum number of fragments 1230 * (due to the limit being lowered), drain off 1231 * enough to get down to the new limit. 1232 */ 1233 if (maxnipq >= 0 && nipq > maxnipq) { 1234 for (i = 0; i < IPREASS_NHASH; i++) { 1235 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1236 ipstat.ips_fragdropped += 1237 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1238 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1239 } 1240 } 1241 } 1242 IPQ_UNLOCK(); 1243 } 1244 1245 /* 1246 * Drain off all datagram fragments. 1247 */ 1248 void 1249 ip_drain() 1250 { 1251 int i; 1252 1253 IPQ_LOCK(); 1254 for (i = 0; i < IPREASS_NHASH; i++) { 1255 while(!TAILQ_EMPTY(&ipq[i])) { 1256 ipstat.ips_fragdropped += 1257 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1258 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1259 } 1260 } 1261 IPQ_UNLOCK(); 1262 in_rtqdrain(); 1263 } 1264 1265 /* 1266 * The protocol to be inserted into ip_protox[] must be already registered 1267 * in inetsw[], either statically or through pf_proto_register(). 1268 */ 1269 int 1270 ipproto_register(u_char ipproto) 1271 { 1272 struct protosw *pr; 1273 1274 /* Sanity checks. */ 1275 if (ipproto == 0) 1276 return (EPROTONOSUPPORT); 1277 1278 /* 1279 * The protocol slot must not be occupied by another protocol 1280 * already. An index pointing to IPPROTO_RAW is unused. 1281 */ 1282 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1283 if (pr == NULL) 1284 return (EPFNOSUPPORT); 1285 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1286 return (EEXIST); 1287 1288 /* Find the protocol position in inetsw[] and set the index. */ 1289 for (pr = inetdomain.dom_protosw; 1290 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1291 if (pr->pr_domain->dom_family == PF_INET && 1292 pr->pr_protocol && pr->pr_protocol == ipproto) { 1293 /* Be careful to only index valid IP protocols. */ 1294 if (pr->pr_protocol < IPPROTO_MAX) { 1295 ip_protox[pr->pr_protocol] = pr - inetsw; 1296 return (0); 1297 } else 1298 return (EINVAL); 1299 } 1300 } 1301 return (EPROTONOSUPPORT); 1302 } 1303 1304 int 1305 ipproto_unregister(u_char ipproto) 1306 { 1307 struct protosw *pr; 1308 1309 /* Sanity checks. */ 1310 if (ipproto == 0) 1311 return (EPROTONOSUPPORT); 1312 1313 /* Check if the protocol was indeed registered. */ 1314 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1315 if (pr == NULL) 1316 return (EPFNOSUPPORT); 1317 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1318 return (ENOENT); 1319 1320 /* Reset the protocol slot to IPPROTO_RAW. */ 1321 ip_protox[ipproto] = pr - inetsw; 1322 return (0); 1323 } 1324 1325 1326 /* 1327 * Do option processing on a datagram, 1328 * possibly discarding it if bad options are encountered, 1329 * or forwarding it if source-routed. 1330 * The pass argument is used when operating in the IPSTEALTH 1331 * mode to tell what options to process: 1332 * [LS]SRR (pass 0) or the others (pass 1). 1333 * The reason for as many as two passes is that when doing IPSTEALTH, 1334 * non-routing options should be processed only if the packet is for us. 1335 * Returns 1 if packet has been forwarded/freed, 1336 * 0 if the packet should be processed further. 1337 */ 1338 static int 1339 ip_dooptions(struct mbuf *m, int pass) 1340 { 1341 struct ip *ip = mtod(m, struct ip *); 1342 u_char *cp; 1343 struct in_ifaddr *ia; 1344 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1345 struct in_addr *sin, dst; 1346 n_time ntime; 1347 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 1348 1349 /* ignore or reject packets with IP options */ 1350 if (ip_doopts == 0) 1351 return 0; 1352 else if (ip_doopts == 2) { 1353 type = ICMP_UNREACH; 1354 code = ICMP_UNREACH_FILTER_PROHIB; 1355 goto bad; 1356 } 1357 1358 dst = ip->ip_dst; 1359 cp = (u_char *)(ip + 1); 1360 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1361 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1362 opt = cp[IPOPT_OPTVAL]; 1363 if (opt == IPOPT_EOL) 1364 break; 1365 if (opt == IPOPT_NOP) 1366 optlen = 1; 1367 else { 1368 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1369 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1370 goto bad; 1371 } 1372 optlen = cp[IPOPT_OLEN]; 1373 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1374 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1375 goto bad; 1376 } 1377 } 1378 switch (opt) { 1379 1380 default: 1381 break; 1382 1383 /* 1384 * Source routing with record. 1385 * Find interface with current destination address. 1386 * If none on this machine then drop if strictly routed, 1387 * or do nothing if loosely routed. 1388 * Record interface address and bring up next address 1389 * component. If strictly routed make sure next 1390 * address is on directly accessible net. 1391 */ 1392 case IPOPT_LSRR: 1393 case IPOPT_SSRR: 1394 #ifdef IPSTEALTH 1395 if (ipstealth && pass > 0) 1396 break; 1397 #endif 1398 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1399 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1400 goto bad; 1401 } 1402 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1403 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1404 goto bad; 1405 } 1406 ipaddr.sin_addr = ip->ip_dst; 1407 ia = (struct in_ifaddr *) 1408 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1409 if (ia == NULL) { 1410 if (opt == IPOPT_SSRR) { 1411 type = ICMP_UNREACH; 1412 code = ICMP_UNREACH_SRCFAIL; 1413 goto bad; 1414 } 1415 if (!ip_dosourceroute) 1416 goto nosourcerouting; 1417 /* 1418 * Loose routing, and not at next destination 1419 * yet; nothing to do except forward. 1420 */ 1421 break; 1422 } 1423 off--; /* 0 origin */ 1424 if (off > optlen - (int)sizeof(struct in_addr)) { 1425 /* 1426 * End of source route. Should be for us. 1427 */ 1428 if (!ip_acceptsourceroute) 1429 goto nosourcerouting; 1430 save_rte(m, cp, ip->ip_src); 1431 break; 1432 } 1433 #ifdef IPSTEALTH 1434 if (ipstealth) 1435 goto dropit; 1436 #endif 1437 if (!ip_dosourceroute) { 1438 if (ipforwarding) { 1439 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1440 /* 1441 * Acting as a router, so generate ICMP 1442 */ 1443 nosourcerouting: 1444 strcpy(buf, inet_ntoa(ip->ip_dst)); 1445 log(LOG_WARNING, 1446 "attempted source route from %s to %s\n", 1447 inet_ntoa(ip->ip_src), buf); 1448 type = ICMP_UNREACH; 1449 code = ICMP_UNREACH_SRCFAIL; 1450 goto bad; 1451 } else { 1452 /* 1453 * Not acting as a router, so silently drop. 1454 */ 1455 #ifdef IPSTEALTH 1456 dropit: 1457 #endif 1458 ipstat.ips_cantforward++; 1459 m_freem(m); 1460 return (1); 1461 } 1462 } 1463 1464 /* 1465 * locate outgoing interface 1466 */ 1467 (void)memcpy(&ipaddr.sin_addr, cp + off, 1468 sizeof(ipaddr.sin_addr)); 1469 1470 if (opt == IPOPT_SSRR) { 1471 #define INA struct in_ifaddr * 1472 #define SA struct sockaddr * 1473 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == NULL) 1474 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1475 } else 1476 ia = ip_rtaddr(ipaddr.sin_addr); 1477 if (ia == NULL) { 1478 type = ICMP_UNREACH; 1479 code = ICMP_UNREACH_SRCFAIL; 1480 goto bad; 1481 } 1482 ip->ip_dst = ipaddr.sin_addr; 1483 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1484 sizeof(struct in_addr)); 1485 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1486 /* 1487 * Let ip_intr's mcast routing check handle mcast pkts 1488 */ 1489 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1490 break; 1491 1492 case IPOPT_RR: 1493 #ifdef IPSTEALTH 1494 if (ipstealth && pass == 0) 1495 break; 1496 #endif 1497 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1498 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1499 goto bad; 1500 } 1501 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1502 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1503 goto bad; 1504 } 1505 /* 1506 * If no space remains, ignore. 1507 */ 1508 off--; /* 0 origin */ 1509 if (off > optlen - (int)sizeof(struct in_addr)) 1510 break; 1511 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1512 sizeof(ipaddr.sin_addr)); 1513 /* 1514 * locate outgoing interface; if we're the destination, 1515 * use the incoming interface (should be same). 1516 */ 1517 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1518 (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) { 1519 type = ICMP_UNREACH; 1520 code = ICMP_UNREACH_HOST; 1521 goto bad; 1522 } 1523 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1524 sizeof(struct in_addr)); 1525 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1526 break; 1527 1528 case IPOPT_TS: 1529 #ifdef IPSTEALTH 1530 if (ipstealth && pass == 0) 1531 break; 1532 #endif 1533 code = cp - (u_char *)ip; 1534 if (optlen < 4 || optlen > 40) { 1535 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1536 goto bad; 1537 } 1538 if ((off = cp[IPOPT_OFFSET]) < 5) { 1539 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1540 goto bad; 1541 } 1542 if (off > optlen - (int)sizeof(int32_t)) { 1543 cp[IPOPT_OFFSET + 1] += (1 << 4); 1544 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1545 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1546 goto bad; 1547 } 1548 break; 1549 } 1550 off--; /* 0 origin */ 1551 sin = (struct in_addr *)(cp + off); 1552 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1553 1554 case IPOPT_TS_TSONLY: 1555 break; 1556 1557 case IPOPT_TS_TSANDADDR: 1558 if (off + sizeof(n_time) + 1559 sizeof(struct in_addr) > optlen) { 1560 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1561 goto bad; 1562 } 1563 ipaddr.sin_addr = dst; 1564 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1565 m->m_pkthdr.rcvif); 1566 if (ia == NULL) 1567 continue; 1568 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1569 sizeof(struct in_addr)); 1570 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1571 off += sizeof(struct in_addr); 1572 break; 1573 1574 case IPOPT_TS_PRESPEC: 1575 if (off + sizeof(n_time) + 1576 sizeof(struct in_addr) > optlen) { 1577 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1578 goto bad; 1579 } 1580 (void)memcpy(&ipaddr.sin_addr, sin, 1581 sizeof(struct in_addr)); 1582 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1583 continue; 1584 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1585 off += sizeof(struct in_addr); 1586 break; 1587 1588 default: 1589 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1590 goto bad; 1591 } 1592 ntime = iptime(); 1593 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1594 cp[IPOPT_OFFSET] += sizeof(n_time); 1595 } 1596 } 1597 if (forward && ipforwarding) { 1598 ip_forward(m, 1); 1599 return (1); 1600 } 1601 return (0); 1602 bad: 1603 icmp_error(m, type, code, 0, 0); 1604 ipstat.ips_badoptions++; 1605 return (1); 1606 } 1607 1608 /* 1609 * Given address of next destination (final or next hop), 1610 * return internet address info of interface to be used to get there. 1611 */ 1612 struct in_ifaddr * 1613 ip_rtaddr(dst) 1614 struct in_addr dst; 1615 { 1616 struct route sro; 1617 struct sockaddr_in *sin; 1618 struct in_ifaddr *ifa; 1619 1620 bzero(&sro, sizeof(sro)); 1621 sin = (struct sockaddr_in *)&sro.ro_dst; 1622 sin->sin_family = AF_INET; 1623 sin->sin_len = sizeof(*sin); 1624 sin->sin_addr = dst; 1625 rtalloc_ign(&sro, RTF_CLONING); 1626 1627 if (sro.ro_rt == NULL) 1628 return (NULL); 1629 1630 ifa = ifatoia(sro.ro_rt->rt_ifa); 1631 RTFREE(sro.ro_rt); 1632 return (ifa); 1633 } 1634 1635 /* 1636 * Save incoming source route for use in replies, 1637 * to be picked up later by ip_srcroute if the receiver is interested. 1638 */ 1639 static void 1640 save_rte(m, option, dst) 1641 struct mbuf *m; 1642 u_char *option; 1643 struct in_addr dst; 1644 { 1645 unsigned olen; 1646 struct ipopt_tag *opts; 1647 1648 opts = (struct ipopt_tag *)m_tag_get(PACKET_TAG_IPOPTIONS, 1649 sizeof(struct ipopt_tag), M_NOWAIT); 1650 if (opts == NULL) 1651 return; 1652 1653 olen = option[IPOPT_OLEN]; 1654 #ifdef DIAGNOSTIC 1655 if (ipprintfs) 1656 printf("save_rte: olen %d\n", olen); 1657 #endif 1658 if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) { 1659 m_tag_free((struct m_tag *)opts); 1660 return; 1661 } 1662 bcopy(option, opts->ip_srcrt.srcopt, olen); 1663 opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1664 opts->ip_srcrt.dst = dst; 1665 m_tag_prepend(m, (struct m_tag *)opts); 1666 } 1667 1668 /* 1669 * Retrieve incoming source route for use in replies, 1670 * in the same form used by setsockopt. 1671 * The first hop is placed before the options, will be removed later. 1672 */ 1673 struct mbuf * 1674 ip_srcroute(m0) 1675 struct mbuf *m0; 1676 { 1677 register struct in_addr *p, *q; 1678 register struct mbuf *m; 1679 struct ipopt_tag *opts; 1680 1681 opts = (struct ipopt_tag *)m_tag_find(m0, PACKET_TAG_IPOPTIONS, NULL); 1682 if (opts == NULL) 1683 return (NULL); 1684 1685 if (opts->ip_nhops == 0) 1686 return (NULL); 1687 m = m_get(M_DONTWAIT, MT_DATA); 1688 if (m == NULL) 1689 return (NULL); 1690 1691 #define OPTSIZ (sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt)) 1692 1693 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1694 m->m_len = opts->ip_nhops * sizeof(struct in_addr) + 1695 sizeof(struct in_addr) + OPTSIZ; 1696 #ifdef DIAGNOSTIC 1697 if (ipprintfs) 1698 printf("ip_srcroute: nhops %d mlen %d", opts->ip_nhops, m->m_len); 1699 #endif 1700 1701 /* 1702 * First save first hop for return route 1703 */ 1704 p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]); 1705 *(mtod(m, struct in_addr *)) = *p--; 1706 #ifdef DIAGNOSTIC 1707 if (ipprintfs) 1708 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1709 #endif 1710 1711 /* 1712 * Copy option fields and padding (nop) to mbuf. 1713 */ 1714 opts->ip_srcrt.nop = IPOPT_NOP; 1715 opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1716 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1717 &(opts->ip_srcrt.nop), OPTSIZ); 1718 q = (struct in_addr *)(mtod(m, caddr_t) + 1719 sizeof(struct in_addr) + OPTSIZ); 1720 #undef OPTSIZ 1721 /* 1722 * Record return path as an IP source route, 1723 * reversing the path (pointers are now aligned). 1724 */ 1725 while (p >= opts->ip_srcrt.route) { 1726 #ifdef DIAGNOSTIC 1727 if (ipprintfs) 1728 printf(" %lx", (u_long)ntohl(q->s_addr)); 1729 #endif 1730 *q++ = *p--; 1731 } 1732 /* 1733 * Last hop goes to final destination. 1734 */ 1735 *q = opts->ip_srcrt.dst; 1736 #ifdef DIAGNOSTIC 1737 if (ipprintfs) 1738 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1739 #endif 1740 m_tag_delete(m0, (struct m_tag *)opts); 1741 return (m); 1742 } 1743 1744 /* 1745 * Strip out IP options, at higher 1746 * level protocol in the kernel. 1747 * Second argument is buffer to which options 1748 * will be moved, and return value is their length. 1749 * XXX should be deleted; last arg currently ignored. 1750 */ 1751 void 1752 ip_stripoptions(m, mopt) 1753 register struct mbuf *m; 1754 struct mbuf *mopt; 1755 { 1756 register int i; 1757 struct ip *ip = mtod(m, struct ip *); 1758 register caddr_t opts; 1759 int olen; 1760 1761 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1762 opts = (caddr_t)(ip + 1); 1763 i = m->m_len - (sizeof (struct ip) + olen); 1764 bcopy(opts + olen, opts, (unsigned)i); 1765 m->m_len -= olen; 1766 if (m->m_flags & M_PKTHDR) 1767 m->m_pkthdr.len -= olen; 1768 ip->ip_v = IPVERSION; 1769 ip->ip_hl = sizeof(struct ip) >> 2; 1770 } 1771 1772 u_char inetctlerrmap[PRC_NCMDS] = { 1773 0, 0, 0, 0, 1774 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1775 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1776 EMSGSIZE, EHOSTUNREACH, 0, 0, 1777 0, 0, EHOSTUNREACH, 0, 1778 ENOPROTOOPT, ECONNREFUSED 1779 }; 1780 1781 /* 1782 * Forward a packet. If some error occurs return the sender 1783 * an icmp packet. Note we can't always generate a meaningful 1784 * icmp message because icmp doesn't have a large enough repertoire 1785 * of codes and types. 1786 * 1787 * If not forwarding, just drop the packet. This could be confusing 1788 * if ipforwarding was zero but some routing protocol was advancing 1789 * us as a gateway to somewhere. However, we must let the routing 1790 * protocol deal with that. 1791 * 1792 * The srcrt parameter indicates whether the packet is being forwarded 1793 * via a source route. 1794 */ 1795 void 1796 ip_forward(struct mbuf *m, int srcrt) 1797 { 1798 struct ip *ip = mtod(m, struct ip *); 1799 struct in_ifaddr *ia = NULL; 1800 struct mbuf *mcopy; 1801 struct in_addr dest; 1802 int error, type = 0, code = 0, mtu = 0; 1803 1804 #ifdef DIAGNOSTIC 1805 if (ipprintfs) 1806 printf("forward: src %lx dst %lx ttl %x\n", 1807 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1808 ip->ip_ttl); 1809 #endif 1810 1811 1812 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1813 ipstat.ips_cantforward++; 1814 m_freem(m); 1815 return; 1816 } 1817 #ifdef IPSTEALTH 1818 if (!ipstealth) { 1819 #endif 1820 if (ip->ip_ttl <= IPTTLDEC) { 1821 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1822 0, 0); 1823 return; 1824 } 1825 #ifdef IPSTEALTH 1826 } 1827 #endif 1828 1829 ia = ip_rtaddr(ip->ip_dst); 1830 if (!srcrt && ia == NULL) { 1831 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1832 return; 1833 } 1834 1835 /* 1836 * Save the IP header and at most 8 bytes of the payload, 1837 * in case we need to generate an ICMP message to the src. 1838 * 1839 * XXX this can be optimized a lot by saving the data in a local 1840 * buffer on the stack (72 bytes at most), and only allocating the 1841 * mbuf if really necessary. The vast majority of the packets 1842 * are forwarded without having to send an ICMP back (either 1843 * because unnecessary, or because rate limited), so we are 1844 * really we are wasting a lot of work here. 1845 * 1846 * We don't use m_copy() because it might return a reference 1847 * to a shared cluster. Both this function and ip_output() 1848 * assume exclusive access to the IP header in `m', so any 1849 * data in a cluster may change before we reach icmp_error(). 1850 */ 1851 MGET(mcopy, M_DONTWAIT, m->m_type); 1852 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1853 /* 1854 * It's probably ok if the pkthdr dup fails (because 1855 * the deep copy of the tag chain failed), but for now 1856 * be conservative and just discard the copy since 1857 * code below may some day want the tags. 1858 */ 1859 m_free(mcopy); 1860 mcopy = NULL; 1861 } 1862 if (mcopy != NULL) { 1863 mcopy->m_len = imin((ip->ip_hl << 2) + 8, 1864 (int)ip->ip_len); 1865 mcopy->m_pkthdr.len = mcopy->m_len; 1866 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1867 } 1868 1869 #ifdef IPSTEALTH 1870 if (!ipstealth) { 1871 #endif 1872 ip->ip_ttl -= IPTTLDEC; 1873 #ifdef IPSTEALTH 1874 } 1875 #endif 1876 1877 /* 1878 * If forwarding packet using same interface that it came in on, 1879 * perhaps should send a redirect to sender to shortcut a hop. 1880 * Only send redirect if source is sending directly to us, 1881 * and if packet was not source routed (or has any options). 1882 * Also, don't send redirect if forwarding using a default route 1883 * or a route modified by a redirect. 1884 */ 1885 dest.s_addr = 0; 1886 if (!srcrt && ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1887 struct sockaddr_in *sin; 1888 struct route ro; 1889 struct rtentry *rt; 1890 1891 bzero(&ro, sizeof(ro)); 1892 sin = (struct sockaddr_in *)&ro.ro_dst; 1893 sin->sin_family = AF_INET; 1894 sin->sin_len = sizeof(*sin); 1895 sin->sin_addr = ip->ip_dst; 1896 rtalloc_ign(&ro, RTF_CLONING); 1897 1898 rt = ro.ro_rt; 1899 1900 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1901 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1902 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1903 u_long src = ntohl(ip->ip_src.s_addr); 1904 1905 if (RTA(rt) && 1906 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1907 if (rt->rt_flags & RTF_GATEWAY) 1908 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1909 else 1910 dest.s_addr = ip->ip_dst.s_addr; 1911 /* Router requirements says to only send host redirects */ 1912 type = ICMP_REDIRECT; 1913 code = ICMP_REDIRECT_HOST; 1914 #ifdef DIAGNOSTIC 1915 if (ipprintfs) 1916 printf("redirect (%d) to %lx\n", code, (u_long)dest.s_addr); 1917 #endif 1918 } 1919 } 1920 if (rt) 1921 RTFREE(rt); 1922 } 1923 1924 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 1925 if (error) 1926 ipstat.ips_cantforward++; 1927 else { 1928 ipstat.ips_forward++; 1929 if (type) 1930 ipstat.ips_redirectsent++; 1931 else { 1932 if (mcopy) 1933 m_freem(mcopy); 1934 return; 1935 } 1936 } 1937 if (mcopy == NULL) 1938 return; 1939 1940 switch (error) { 1941 1942 case 0: /* forwarded, but need redirect */ 1943 /* type, code set above */ 1944 break; 1945 1946 case ENETUNREACH: /* shouldn't happen, checked above */ 1947 case EHOSTUNREACH: 1948 case ENETDOWN: 1949 case EHOSTDOWN: 1950 default: 1951 type = ICMP_UNREACH; 1952 code = ICMP_UNREACH_HOST; 1953 break; 1954 1955 case EMSGSIZE: 1956 type = ICMP_UNREACH; 1957 code = ICMP_UNREACH_NEEDFRAG; 1958 #if defined(IPSEC) || defined(FAST_IPSEC) 1959 /* 1960 * If the packet is routed over IPsec tunnel, tell the 1961 * originator the tunnel MTU. 1962 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1963 * XXX quickhack!!! 1964 */ 1965 { 1966 struct secpolicy *sp = NULL; 1967 int ipsecerror; 1968 int ipsechdr; 1969 struct route *ro; 1970 1971 #ifdef IPSEC 1972 sp = ipsec4_getpolicybyaddr(mcopy, 1973 IPSEC_DIR_OUTBOUND, 1974 IP_FORWARDING, 1975 &ipsecerror); 1976 #else /* FAST_IPSEC */ 1977 sp = ipsec_getpolicybyaddr(mcopy, 1978 IPSEC_DIR_OUTBOUND, 1979 IP_FORWARDING, 1980 &ipsecerror); 1981 #endif 1982 if (sp != NULL) { 1983 /* count IPsec header size */ 1984 ipsechdr = ipsec4_hdrsiz(mcopy, 1985 IPSEC_DIR_OUTBOUND, 1986 NULL); 1987 1988 /* 1989 * find the correct route for outer IPv4 1990 * header, compute tunnel MTU. 1991 */ 1992 if (sp->req != NULL 1993 && sp->req->sav != NULL 1994 && sp->req->sav->sah != NULL) { 1995 ro = &sp->req->sav->sah->sa_route; 1996 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1997 mtu = 1998 ro->ro_rt->rt_rmx.rmx_mtu ? 1999 ro->ro_rt->rt_rmx.rmx_mtu : 2000 ro->ro_rt->rt_ifp->if_mtu; 2001 mtu -= ipsechdr; 2002 } 2003 } 2004 2005 #ifdef IPSEC 2006 key_freesp(sp); 2007 #else /* FAST_IPSEC */ 2008 KEY_FREESP(&sp); 2009 #endif 2010 } 2011 } 2012 #endif /*IPSEC || FAST_IPSEC*/ 2013 /* 2014 * If the MTU wasn't set before use the interface mtu or 2015 * fall back to the next smaller mtu step compared to the 2016 * current packet size. 2017 */ 2018 if (mtu == 0) { 2019 if (ia != NULL) 2020 mtu = ia->ia_ifp->if_mtu; 2021 else 2022 mtu = ip_next_mtu(ip->ip_len, 0); 2023 } 2024 ipstat.ips_cantfrag++; 2025 break; 2026 2027 case ENOBUFS: 2028 /* 2029 * A router should not generate ICMP_SOURCEQUENCH as 2030 * required in RFC1812 Requirements for IP Version 4 Routers. 2031 * Source quench could be a big problem under DoS attacks, 2032 * or if the underlying interface is rate-limited. 2033 * Those who need source quench packets may re-enable them 2034 * via the net.inet.ip.sendsourcequench sysctl. 2035 */ 2036 if (ip_sendsourcequench == 0) { 2037 m_freem(mcopy); 2038 return; 2039 } else { 2040 type = ICMP_SOURCEQUENCH; 2041 code = 0; 2042 } 2043 break; 2044 2045 case EACCES: /* ipfw denied packet */ 2046 m_freem(mcopy); 2047 return; 2048 } 2049 icmp_error(mcopy, type, code, dest.s_addr, mtu); 2050 } 2051 2052 void 2053 ip_savecontrol(inp, mp, ip, m) 2054 register struct inpcb *inp; 2055 register struct mbuf **mp; 2056 register struct ip *ip; 2057 register struct mbuf *m; 2058 { 2059 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 2060 struct bintime bt; 2061 2062 bintime(&bt); 2063 if (inp->inp_socket->so_options & SO_BINTIME) { 2064 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 2065 SCM_BINTIME, SOL_SOCKET); 2066 if (*mp) 2067 mp = &(*mp)->m_next; 2068 } 2069 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2070 struct timeval tv; 2071 2072 bintime2timeval(&bt, &tv); 2073 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2074 SCM_TIMESTAMP, SOL_SOCKET); 2075 if (*mp) 2076 mp = &(*mp)->m_next; 2077 } 2078 } 2079 if (inp->inp_flags & INP_RECVDSTADDR) { 2080 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2081 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2082 if (*mp) 2083 mp = &(*mp)->m_next; 2084 } 2085 if (inp->inp_flags & INP_RECVTTL) { 2086 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2087 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2088 if (*mp) 2089 mp = &(*mp)->m_next; 2090 } 2091 #ifdef notyet 2092 /* XXX 2093 * Moving these out of udp_input() made them even more broken 2094 * than they already were. 2095 */ 2096 /* options were tossed already */ 2097 if (inp->inp_flags & INP_RECVOPTS) { 2098 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2099 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2100 if (*mp) 2101 mp = &(*mp)->m_next; 2102 } 2103 /* ip_srcroute doesn't do what we want here, need to fix */ 2104 if (inp->inp_flags & INP_RECVRETOPTS) { 2105 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 2106 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2107 if (*mp) 2108 mp = &(*mp)->m_next; 2109 } 2110 #endif 2111 if (inp->inp_flags & INP_RECVIF) { 2112 struct ifnet *ifp; 2113 struct sdlbuf { 2114 struct sockaddr_dl sdl; 2115 u_char pad[32]; 2116 } sdlbuf; 2117 struct sockaddr_dl *sdp; 2118 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2119 2120 if (((ifp = m->m_pkthdr.rcvif)) 2121 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2122 sdp = (struct sockaddr_dl *) 2123 (ifaddr_byindex(ifp->if_index)->ifa_addr); 2124 /* 2125 * Change our mind and don't try copy. 2126 */ 2127 if ((sdp->sdl_family != AF_LINK) 2128 || (sdp->sdl_len > sizeof(sdlbuf))) { 2129 goto makedummy; 2130 } 2131 bcopy(sdp, sdl2, sdp->sdl_len); 2132 } else { 2133 makedummy: 2134 sdl2->sdl_len 2135 = offsetof(struct sockaddr_dl, sdl_data[0]); 2136 sdl2->sdl_family = AF_LINK; 2137 sdl2->sdl_index = 0; 2138 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2139 } 2140 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2141 IP_RECVIF, IPPROTO_IP); 2142 if (*mp) 2143 mp = &(*mp)->m_next; 2144 } 2145 } 2146 2147 /* 2148 * XXX these routines are called from the upper part of the kernel. 2149 * They need to be locked when we remove Giant. 2150 * 2151 * They could also be moved to ip_mroute.c, since all the RSVP 2152 * handling is done there already. 2153 */ 2154 static int ip_rsvp_on; 2155 struct socket *ip_rsvpd; 2156 int 2157 ip_rsvp_init(struct socket *so) 2158 { 2159 if (so->so_type != SOCK_RAW || 2160 so->so_proto->pr_protocol != IPPROTO_RSVP) 2161 return EOPNOTSUPP; 2162 2163 if (ip_rsvpd != NULL) 2164 return EADDRINUSE; 2165 2166 ip_rsvpd = so; 2167 /* 2168 * This may seem silly, but we need to be sure we don't over-increment 2169 * the RSVP counter, in case something slips up. 2170 */ 2171 if (!ip_rsvp_on) { 2172 ip_rsvp_on = 1; 2173 rsvp_on++; 2174 } 2175 2176 return 0; 2177 } 2178 2179 int 2180 ip_rsvp_done(void) 2181 { 2182 ip_rsvpd = NULL; 2183 /* 2184 * This may seem silly, but we need to be sure we don't over-decrement 2185 * the RSVP counter, in case something slips up. 2186 */ 2187 if (ip_rsvp_on) { 2188 ip_rsvp_on = 0; 2189 rsvp_on--; 2190 } 2191 return 0; 2192 } 2193 2194 void 2195 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 2196 { 2197 if (rsvp_input_p) { /* call the real one if loaded */ 2198 rsvp_input_p(m, off); 2199 return; 2200 } 2201 2202 /* Can still get packets with rsvp_on = 0 if there is a local member 2203 * of the group to which the RSVP packet is addressed. But in this 2204 * case we want to throw the packet away. 2205 */ 2206 2207 if (!rsvp_on) { 2208 m_freem(m); 2209 return; 2210 } 2211 2212 if (ip_rsvpd != NULL) { 2213 rip_input(m, off); 2214 return; 2215 } 2216 /* Drop the packet */ 2217 m_freem(m); 2218 }
Cache object: 58f23684e6748df7c06f540dc3e0299a
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]