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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/6.2/sys/netinet/ip_input.c 161987 2006-09-04 10:39:47Z pjd $ 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 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 587 struct in_multi *inm; 588 if (ip_mrouter) { 589 /* 590 * If we are acting as a multicast router, all 591 * incoming multicast packets are passed to the 592 * kernel-level multicast forwarding function. 593 * The packet is returned (relatively) intact; if 594 * ip_mforward() returns a non-zero value, the packet 595 * must be discarded, else it may be accepted below. 596 */ 597 if (ip_mforward && 598 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 599 ipstat.ips_cantforward++; 600 m_freem(m); 601 return; 602 } 603 604 /* 605 * The process-level routing daemon needs to receive 606 * all multicast IGMP packets, whether or not this 607 * host belongs to their destination groups. 608 */ 609 if (ip->ip_p == IPPROTO_IGMP) 610 goto ours; 611 ipstat.ips_forward++; 612 } 613 /* 614 * See if we belong to the destination multicast group on the 615 * arrival interface. 616 */ 617 IN_MULTI_LOCK(); 618 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 619 IN_MULTI_UNLOCK(); 620 if (inm == NULL) { 621 ipstat.ips_notmember++; 622 m_freem(m); 623 return; 624 } 625 goto ours; 626 } 627 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 628 goto ours; 629 if (ip->ip_dst.s_addr == INADDR_ANY) 630 goto ours; 631 632 /* 633 * FAITH(Firewall Aided Internet Translator) 634 */ 635 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 636 if (ip_keepfaith) { 637 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 638 goto ours; 639 } 640 m_freem(m); 641 return; 642 } 643 644 /* 645 * Not for us; forward if possible and desirable. 646 */ 647 if (ipforwarding == 0) { 648 ipstat.ips_cantforward++; 649 m_freem(m); 650 } else { 651 #ifdef IPSEC 652 /* 653 * Enforce inbound IPsec SPD. 654 */ 655 if (ipsec4_in_reject(m, NULL)) { 656 ipsecstat.in_polvio++; 657 goto bad; 658 } 659 #endif /* IPSEC */ 660 #ifdef FAST_IPSEC 661 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 662 s = splnet(); 663 if (mtag != NULL) { 664 tdbi = (struct tdb_ident *)(mtag + 1); 665 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 666 } else { 667 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 668 IP_FORWARDING, &error); 669 } 670 if (sp == NULL) { /* NB: can happen if error */ 671 splx(s); 672 /*XXX error stat???*/ 673 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 674 goto bad; 675 } 676 677 /* 678 * Check security policy against packet attributes. 679 */ 680 error = ipsec_in_reject(sp, m); 681 KEY_FREESP(&sp); 682 splx(s); 683 if (error) { 684 ipstat.ips_cantforward++; 685 goto bad; 686 } 687 #endif /* FAST_IPSEC */ 688 ip_forward(m, dchg); 689 } 690 return; 691 692 ours: 693 #ifdef IPSTEALTH 694 /* 695 * IPSTEALTH: Process non-routing options only 696 * if the packet is destined for us. 697 */ 698 if (ipstealth && hlen > sizeof (struct ip) && 699 ip_dooptions(m, 1)) 700 return; 701 #endif /* IPSTEALTH */ 702 703 /* Count the packet in the ip address stats */ 704 if (ia != NULL) { 705 ia->ia_ifa.if_ipackets++; 706 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 707 } 708 709 /* 710 * Attempt reassembly; if it succeeds, proceed. 711 * ip_reass() will return a different mbuf. 712 */ 713 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 714 m = ip_reass(m); 715 if (m == NULL) 716 return; 717 ip = mtod(m, struct ip *); 718 /* Get the header length of the reassembled packet */ 719 hlen = ip->ip_hl << 2; 720 } 721 722 /* 723 * Further protocols expect the packet length to be w/o the 724 * IP header. 725 */ 726 ip->ip_len -= hlen; 727 728 #ifdef IPSEC 729 /* 730 * enforce IPsec policy checking if we are seeing last header. 731 * note that we do not visit this with protocols with pcb layer 732 * code - like udp/tcp/raw ip. 733 */ 734 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 735 ipsec4_in_reject(m, NULL)) { 736 ipsecstat.in_polvio++; 737 goto bad; 738 } 739 #endif 740 #if FAST_IPSEC 741 /* 742 * enforce IPsec policy checking if we are seeing last header. 743 * note that we do not visit this with protocols with pcb layer 744 * code - like udp/tcp/raw ip. 745 */ 746 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 747 /* 748 * Check if the packet has already had IPsec processing 749 * done. If so, then just pass it along. This tag gets 750 * set during AH, ESP, etc. input handling, before the 751 * packet is returned to the ip input queue for delivery. 752 */ 753 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 754 s = splnet(); 755 if (mtag != NULL) { 756 tdbi = (struct tdb_ident *)(mtag + 1); 757 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 758 } else { 759 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 760 IP_FORWARDING, &error); 761 } 762 if (sp != NULL) { 763 /* 764 * Check security policy against packet attributes. 765 */ 766 error = ipsec_in_reject(sp, m); 767 KEY_FREESP(&sp); 768 } else { 769 /* XXX error stat??? */ 770 error = EINVAL; 771 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 772 goto bad; 773 } 774 splx(s); 775 if (error) 776 goto bad; 777 } 778 #endif /* FAST_IPSEC */ 779 780 /* 781 * Switch out to protocol's input routine. 782 */ 783 ipstat.ips_delivered++; 784 785 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 786 return; 787 bad: 788 m_freem(m); 789 } 790 791 /* 792 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 793 * max has slightly different semantics than the sysctl, for historical 794 * reasons. 795 */ 796 static void 797 maxnipq_update(void) 798 { 799 800 /* 801 * -1 for unlimited allocation. 802 */ 803 if (maxnipq < 0) 804 uma_zone_set_max(ipq_zone, 0); 805 /* 806 * Positive number for specific bound. 807 */ 808 if (maxnipq > 0) 809 uma_zone_set_max(ipq_zone, maxnipq); 810 /* 811 * Zero specifies no further fragment queue allocation -- set the 812 * bound very low, but rely on implementation elsewhere to actually 813 * prevent allocation and reclaim current queues. 814 */ 815 if (maxnipq == 0) 816 uma_zone_set_max(ipq_zone, 1); 817 } 818 819 static void 820 ipq_zone_change(void *tag) 821 { 822 823 if (maxnipq > 0 && maxnipq < (nmbclusters / 32)) { 824 maxnipq = nmbclusters / 32; 825 maxnipq_update(); 826 } 827 } 828 829 static int 830 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 831 { 832 int error, i; 833 834 i = maxnipq; 835 error = sysctl_handle_int(oidp, &i, 0, req); 836 if (error || !req->newptr) 837 return (error); 838 839 /* 840 * XXXRW: Might be a good idea to sanity check the argument and place 841 * an extreme upper bound. 842 */ 843 if (i < -1) 844 return (EINVAL); 845 maxnipq = i; 846 maxnipq_update(); 847 return (0); 848 } 849 850 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 851 NULL, 0, sysctl_maxnipq, "I", 852 "Maximum number of IPv4 fragment reassembly queue entries"); 853 854 /* 855 * Take incoming datagram fragment and try to reassemble it into 856 * whole datagram. If the argument is the first fragment or one 857 * in between the function will return NULL and store the mbuf 858 * in the fragment chain. If the argument is the last fragment 859 * the packet will be reassembled and the pointer to the new 860 * mbuf returned for further processing. Only m_tags attached 861 * to the first packet/fragment are preserved. 862 * The IP header is *NOT* adjusted out of iplen. 863 */ 864 865 struct mbuf * 866 ip_reass(struct mbuf *m) 867 { 868 struct ip *ip; 869 struct mbuf *p, *q, *nq, *t; 870 struct ipq *fp = NULL; 871 struct ipqhead *head; 872 int i, hlen, next; 873 u_int8_t ecn, ecn0; 874 u_short hash; 875 876 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 877 if (maxnipq == 0 || maxfragsperpacket == 0) { 878 ipstat.ips_fragments++; 879 ipstat.ips_fragdropped++; 880 m_freem(m); 881 return (NULL); 882 } 883 884 ip = mtod(m, struct ip *); 885 hlen = ip->ip_hl << 2; 886 887 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 888 head = &ipq[hash]; 889 IPQ_LOCK(); 890 891 /* 892 * Look for queue of fragments 893 * of this datagram. 894 */ 895 TAILQ_FOREACH(fp, head, ipq_list) 896 if (ip->ip_id == fp->ipq_id && 897 ip->ip_src.s_addr == fp->ipq_src.s_addr && 898 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 899 #ifdef MAC 900 mac_fragment_match(m, fp) && 901 #endif 902 ip->ip_p == fp->ipq_p) 903 goto found; 904 905 fp = NULL; 906 907 /* 908 * Attempt to trim the number of allocated fragment queues if it 909 * exceeds the administrative limit. 910 */ 911 if ((nipq > maxnipq) && (maxnipq > 0)) { 912 /* 913 * drop something from the tail of the current queue 914 * before proceeding further 915 */ 916 struct ipq *q = TAILQ_LAST(head, ipqhead); 917 if (q == NULL) { /* gak */ 918 for (i = 0; i < IPREASS_NHASH; i++) { 919 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 920 if (r) { 921 ipstat.ips_fragtimeout += r->ipq_nfrags; 922 ip_freef(&ipq[i], r); 923 break; 924 } 925 } 926 } else { 927 ipstat.ips_fragtimeout += q->ipq_nfrags; 928 ip_freef(head, q); 929 } 930 } 931 932 found: 933 /* 934 * Adjust ip_len to not reflect header, 935 * convert offset of this to bytes. 936 */ 937 ip->ip_len -= hlen; 938 if (ip->ip_off & IP_MF) { 939 /* 940 * Make sure that fragments have a data length 941 * that's a non-zero multiple of 8 bytes. 942 */ 943 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 944 ipstat.ips_toosmall++; /* XXX */ 945 goto dropfrag; 946 } 947 m->m_flags |= M_FRAG; 948 } else 949 m->m_flags &= ~M_FRAG; 950 ip->ip_off <<= 3; 951 952 953 /* 954 * Attempt reassembly; if it succeeds, proceed. 955 * ip_reass() will return a different mbuf. 956 */ 957 ipstat.ips_fragments++; 958 m->m_pkthdr.header = ip; 959 960 /* Previous ip_reass() started here. */ 961 /* 962 * Presence of header sizes in mbufs 963 * would confuse code below. 964 */ 965 m->m_data += hlen; 966 m->m_len -= hlen; 967 968 /* 969 * If first fragment to arrive, create a reassembly queue. 970 */ 971 if (fp == NULL) { 972 fp = uma_zalloc(ipq_zone, M_NOWAIT); 973 if (fp == NULL) 974 goto dropfrag; 975 #ifdef MAC 976 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 977 uma_zfree(ipq_zone, fp); 978 fp = NULL; 979 goto dropfrag; 980 } 981 mac_create_ipq(m, fp); 982 #endif 983 TAILQ_INSERT_HEAD(head, fp, ipq_list); 984 nipq++; 985 fp->ipq_nfrags = 1; 986 fp->ipq_ttl = IPFRAGTTL; 987 fp->ipq_p = ip->ip_p; 988 fp->ipq_id = ip->ip_id; 989 fp->ipq_src = ip->ip_src; 990 fp->ipq_dst = ip->ip_dst; 991 fp->ipq_frags = m; 992 m->m_nextpkt = NULL; 993 goto done; 994 } else { 995 fp->ipq_nfrags++; 996 #ifdef MAC 997 mac_update_ipq(m, fp); 998 #endif 999 } 1000 1001 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1002 1003 /* 1004 * Handle ECN by comparing this segment with the first one; 1005 * if CE is set, do not lose CE. 1006 * drop if CE and not-ECT are mixed for the same packet. 1007 */ 1008 ecn = ip->ip_tos & IPTOS_ECN_MASK; 1009 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 1010 if (ecn == IPTOS_ECN_CE) { 1011 if (ecn0 == IPTOS_ECN_NOTECT) 1012 goto dropfrag; 1013 if (ecn0 != IPTOS_ECN_CE) 1014 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 1015 } 1016 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 1017 goto dropfrag; 1018 1019 /* 1020 * Find a segment which begins after this one does. 1021 */ 1022 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1023 if (GETIP(q)->ip_off > ip->ip_off) 1024 break; 1025 1026 /* 1027 * If there is a preceding segment, it may provide some of 1028 * our data already. If so, drop the data from the incoming 1029 * segment. If it provides all of our data, drop us, otherwise 1030 * stick new segment in the proper place. 1031 * 1032 * If some of the data is dropped from the the preceding 1033 * segment, then it's checksum is invalidated. 1034 */ 1035 if (p) { 1036 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1037 if (i > 0) { 1038 if (i >= ip->ip_len) 1039 goto dropfrag; 1040 m_adj(m, i); 1041 m->m_pkthdr.csum_flags = 0; 1042 ip->ip_off += i; 1043 ip->ip_len -= i; 1044 } 1045 m->m_nextpkt = p->m_nextpkt; 1046 p->m_nextpkt = m; 1047 } else { 1048 m->m_nextpkt = fp->ipq_frags; 1049 fp->ipq_frags = m; 1050 } 1051 1052 /* 1053 * While we overlap succeeding segments trim them or, 1054 * if they are completely covered, dequeue them. 1055 */ 1056 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1057 q = nq) { 1058 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1059 if (i < GETIP(q)->ip_len) { 1060 GETIP(q)->ip_len -= i; 1061 GETIP(q)->ip_off += i; 1062 m_adj(q, i); 1063 q->m_pkthdr.csum_flags = 0; 1064 break; 1065 } 1066 nq = q->m_nextpkt; 1067 m->m_nextpkt = nq; 1068 ipstat.ips_fragdropped++; 1069 fp->ipq_nfrags--; 1070 m_freem(q); 1071 } 1072 1073 /* 1074 * Check for complete reassembly and perform frag per packet 1075 * limiting. 1076 * 1077 * Frag limiting is performed here so that the nth frag has 1078 * a chance to complete the packet before we drop the packet. 1079 * As a result, n+1 frags are actually allowed per packet, but 1080 * only n will ever be stored. (n = maxfragsperpacket.) 1081 * 1082 */ 1083 next = 0; 1084 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1085 if (GETIP(q)->ip_off != next) { 1086 if (fp->ipq_nfrags > maxfragsperpacket) { 1087 ipstat.ips_fragdropped += fp->ipq_nfrags; 1088 ip_freef(head, fp); 1089 } 1090 goto done; 1091 } 1092 next += GETIP(q)->ip_len; 1093 } 1094 /* Make sure the last packet didn't have the IP_MF flag */ 1095 if (p->m_flags & M_FRAG) { 1096 if (fp->ipq_nfrags > maxfragsperpacket) { 1097 ipstat.ips_fragdropped += fp->ipq_nfrags; 1098 ip_freef(head, fp); 1099 } 1100 goto done; 1101 } 1102 1103 /* 1104 * Reassembly is complete. Make sure the packet is a sane size. 1105 */ 1106 q = fp->ipq_frags; 1107 ip = GETIP(q); 1108 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1109 ipstat.ips_toolong++; 1110 ipstat.ips_fragdropped += fp->ipq_nfrags; 1111 ip_freef(head, fp); 1112 goto done; 1113 } 1114 1115 /* 1116 * Concatenate fragments. 1117 */ 1118 m = q; 1119 t = m->m_next; 1120 m->m_next = NULL; 1121 m_cat(m, t); 1122 nq = q->m_nextpkt; 1123 q->m_nextpkt = NULL; 1124 for (q = nq; q != NULL; q = nq) { 1125 nq = q->m_nextpkt; 1126 q->m_nextpkt = NULL; 1127 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1128 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1129 m_cat(m, q); 1130 } 1131 /* 1132 * In order to do checksumming faster we do 'end-around carry' here 1133 * (and not in for{} loop), though it implies we are not going to 1134 * reassemble more than 64k fragments. 1135 */ 1136 m->m_pkthdr.csum_data = 1137 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1138 #ifdef MAC 1139 mac_create_datagram_from_ipq(fp, m); 1140 mac_destroy_ipq(fp); 1141 #endif 1142 1143 /* 1144 * Create header for new ip packet by modifying header of first 1145 * packet; dequeue and discard fragment reassembly header. 1146 * Make header visible. 1147 */ 1148 ip->ip_len = (ip->ip_hl << 2) + next; 1149 ip->ip_src = fp->ipq_src; 1150 ip->ip_dst = fp->ipq_dst; 1151 TAILQ_REMOVE(head, fp, ipq_list); 1152 nipq--; 1153 uma_zfree(ipq_zone, fp); 1154 m->m_len += (ip->ip_hl << 2); 1155 m->m_data -= (ip->ip_hl << 2); 1156 /* some debugging cruft by sklower, below, will go away soon */ 1157 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1158 m_fixhdr(m); 1159 ipstat.ips_reassembled++; 1160 IPQ_UNLOCK(); 1161 return (m); 1162 1163 dropfrag: 1164 ipstat.ips_fragdropped++; 1165 if (fp != NULL) 1166 fp->ipq_nfrags--; 1167 m_freem(m); 1168 done: 1169 IPQ_UNLOCK(); 1170 return (NULL); 1171 1172 #undef GETIP 1173 } 1174 1175 /* 1176 * Free a fragment reassembly header and all 1177 * associated datagrams. 1178 */ 1179 static void 1180 ip_freef(fhp, fp) 1181 struct ipqhead *fhp; 1182 struct ipq *fp; 1183 { 1184 register struct mbuf *q; 1185 1186 IPQ_LOCK_ASSERT(); 1187 1188 while (fp->ipq_frags) { 1189 q = fp->ipq_frags; 1190 fp->ipq_frags = q->m_nextpkt; 1191 m_freem(q); 1192 } 1193 TAILQ_REMOVE(fhp, fp, ipq_list); 1194 uma_zfree(ipq_zone, fp); 1195 nipq--; 1196 } 1197 1198 /* 1199 * IP timer processing; 1200 * if a timer expires on a reassembly 1201 * queue, discard it. 1202 */ 1203 void 1204 ip_slowtimo() 1205 { 1206 register struct ipq *fp; 1207 int i; 1208 1209 IPQ_LOCK(); 1210 for (i = 0; i < IPREASS_NHASH; i++) { 1211 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1212 struct ipq *fpp; 1213 1214 fpp = fp; 1215 fp = TAILQ_NEXT(fp, ipq_list); 1216 if(--fpp->ipq_ttl == 0) { 1217 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1218 ip_freef(&ipq[i], fpp); 1219 } 1220 } 1221 } 1222 /* 1223 * If we are over the maximum number of fragments 1224 * (due to the limit being lowered), drain off 1225 * enough to get down to the new limit. 1226 */ 1227 if (maxnipq >= 0 && nipq > maxnipq) { 1228 for (i = 0; i < IPREASS_NHASH; i++) { 1229 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1230 ipstat.ips_fragdropped += 1231 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1232 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1233 } 1234 } 1235 } 1236 IPQ_UNLOCK(); 1237 } 1238 1239 /* 1240 * Drain off all datagram fragments. 1241 */ 1242 void 1243 ip_drain() 1244 { 1245 int i; 1246 1247 IPQ_LOCK(); 1248 for (i = 0; i < IPREASS_NHASH; i++) { 1249 while(!TAILQ_EMPTY(&ipq[i])) { 1250 ipstat.ips_fragdropped += 1251 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1252 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1253 } 1254 } 1255 IPQ_UNLOCK(); 1256 in_rtqdrain(); 1257 } 1258 1259 /* 1260 * The protocol to be inserted into ip_protox[] must be already registered 1261 * in inetsw[], either statically or through pf_proto_register(). 1262 */ 1263 int 1264 ipproto_register(u_char ipproto) 1265 { 1266 struct protosw *pr; 1267 1268 /* Sanity checks. */ 1269 if (ipproto == 0) 1270 return (EPROTONOSUPPORT); 1271 1272 /* 1273 * The protocol slot must not be occupied by another protocol 1274 * already. An index pointing to IPPROTO_RAW is unused. 1275 */ 1276 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1277 if (pr == NULL) 1278 return (EPFNOSUPPORT); 1279 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1280 return (EEXIST); 1281 1282 /* Find the protocol position in inetsw[] and set the index. */ 1283 for (pr = inetdomain.dom_protosw; 1284 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1285 if (pr->pr_domain->dom_family == PF_INET && 1286 pr->pr_protocol && pr->pr_protocol == ipproto) { 1287 /* Be careful to only index valid IP protocols. */ 1288 if (pr->pr_protocol < IPPROTO_MAX) { 1289 ip_protox[pr->pr_protocol] = pr - inetsw; 1290 return (0); 1291 } else 1292 return (EINVAL); 1293 } 1294 } 1295 return (EPROTONOSUPPORT); 1296 } 1297 1298 int 1299 ipproto_unregister(u_char ipproto) 1300 { 1301 struct protosw *pr; 1302 1303 /* Sanity checks. */ 1304 if (ipproto == 0) 1305 return (EPROTONOSUPPORT); 1306 1307 /* Check if the protocol was indeed registered. */ 1308 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1309 if (pr == NULL) 1310 return (EPFNOSUPPORT); 1311 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1312 return (ENOENT); 1313 1314 /* Reset the protocol slot to IPPROTO_RAW. */ 1315 ip_protox[ipproto] = pr - inetsw; 1316 return (0); 1317 } 1318 1319 1320 /* 1321 * Do option processing on a datagram, 1322 * possibly discarding it if bad options are encountered, 1323 * or forwarding it if source-routed. 1324 * The pass argument is used when operating in the IPSTEALTH 1325 * mode to tell what options to process: 1326 * [LS]SRR (pass 0) or the others (pass 1). 1327 * The reason for as many as two passes is that when doing IPSTEALTH, 1328 * non-routing options should be processed only if the packet is for us. 1329 * Returns 1 if packet has been forwarded/freed, 1330 * 0 if the packet should be processed further. 1331 */ 1332 static int 1333 ip_dooptions(struct mbuf *m, int pass) 1334 { 1335 struct ip *ip = mtod(m, struct ip *); 1336 u_char *cp; 1337 struct in_ifaddr *ia; 1338 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1339 struct in_addr *sin, dst; 1340 n_time ntime; 1341 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 1342 1343 /* ignore or reject packets with IP options */ 1344 if (ip_doopts == 0) 1345 return 0; 1346 else if (ip_doopts == 2) { 1347 type = ICMP_UNREACH; 1348 code = ICMP_UNREACH_FILTER_PROHIB; 1349 goto bad; 1350 } 1351 1352 dst = ip->ip_dst; 1353 cp = (u_char *)(ip + 1); 1354 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1355 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1356 opt = cp[IPOPT_OPTVAL]; 1357 if (opt == IPOPT_EOL) 1358 break; 1359 if (opt == IPOPT_NOP) 1360 optlen = 1; 1361 else { 1362 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1363 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1364 goto bad; 1365 } 1366 optlen = cp[IPOPT_OLEN]; 1367 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1368 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1369 goto bad; 1370 } 1371 } 1372 switch (opt) { 1373 1374 default: 1375 break; 1376 1377 /* 1378 * Source routing with record. 1379 * Find interface with current destination address. 1380 * If none on this machine then drop if strictly routed, 1381 * or do nothing if loosely routed. 1382 * Record interface address and bring up next address 1383 * component. If strictly routed make sure next 1384 * address is on directly accessible net. 1385 */ 1386 case IPOPT_LSRR: 1387 case IPOPT_SSRR: 1388 #ifdef IPSTEALTH 1389 if (ipstealth && pass > 0) 1390 break; 1391 #endif 1392 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1393 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1394 goto bad; 1395 } 1396 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1397 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1398 goto bad; 1399 } 1400 ipaddr.sin_addr = ip->ip_dst; 1401 ia = (struct in_ifaddr *) 1402 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1403 if (ia == NULL) { 1404 if (opt == IPOPT_SSRR) { 1405 type = ICMP_UNREACH; 1406 code = ICMP_UNREACH_SRCFAIL; 1407 goto bad; 1408 } 1409 if (!ip_dosourceroute) 1410 goto nosourcerouting; 1411 /* 1412 * Loose routing, and not at next destination 1413 * yet; nothing to do except forward. 1414 */ 1415 break; 1416 } 1417 off--; /* 0 origin */ 1418 if (off > optlen - (int)sizeof(struct in_addr)) { 1419 /* 1420 * End of source route. Should be for us. 1421 */ 1422 if (!ip_acceptsourceroute) 1423 goto nosourcerouting; 1424 save_rte(m, cp, ip->ip_src); 1425 break; 1426 } 1427 #ifdef IPSTEALTH 1428 if (ipstealth) 1429 goto dropit; 1430 #endif 1431 if (!ip_dosourceroute) { 1432 if (ipforwarding) { 1433 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1434 /* 1435 * Acting as a router, so generate ICMP 1436 */ 1437 nosourcerouting: 1438 strcpy(buf, inet_ntoa(ip->ip_dst)); 1439 log(LOG_WARNING, 1440 "attempted source route from %s to %s\n", 1441 inet_ntoa(ip->ip_src), buf); 1442 type = ICMP_UNREACH; 1443 code = ICMP_UNREACH_SRCFAIL; 1444 goto bad; 1445 } else { 1446 /* 1447 * Not acting as a router, so silently drop. 1448 */ 1449 #ifdef IPSTEALTH 1450 dropit: 1451 #endif 1452 ipstat.ips_cantforward++; 1453 m_freem(m); 1454 return (1); 1455 } 1456 } 1457 1458 /* 1459 * locate outgoing interface 1460 */ 1461 (void)memcpy(&ipaddr.sin_addr, cp + off, 1462 sizeof(ipaddr.sin_addr)); 1463 1464 if (opt == IPOPT_SSRR) { 1465 #define INA struct in_ifaddr * 1466 #define SA struct sockaddr * 1467 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == NULL) 1468 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1469 } else 1470 ia = ip_rtaddr(ipaddr.sin_addr); 1471 if (ia == NULL) { 1472 type = ICMP_UNREACH; 1473 code = ICMP_UNREACH_SRCFAIL; 1474 goto bad; 1475 } 1476 ip->ip_dst = ipaddr.sin_addr; 1477 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1478 sizeof(struct in_addr)); 1479 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1480 /* 1481 * Let ip_intr's mcast routing check handle mcast pkts 1482 */ 1483 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1484 break; 1485 1486 case IPOPT_RR: 1487 #ifdef IPSTEALTH 1488 if (ipstealth && pass == 0) 1489 break; 1490 #endif 1491 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1492 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1493 goto bad; 1494 } 1495 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1496 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1497 goto bad; 1498 } 1499 /* 1500 * If no space remains, ignore. 1501 */ 1502 off--; /* 0 origin */ 1503 if (off > optlen - (int)sizeof(struct in_addr)) 1504 break; 1505 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1506 sizeof(ipaddr.sin_addr)); 1507 /* 1508 * locate outgoing interface; if we're the destination, 1509 * use the incoming interface (should be same). 1510 */ 1511 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1512 (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) { 1513 type = ICMP_UNREACH; 1514 code = ICMP_UNREACH_HOST; 1515 goto bad; 1516 } 1517 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1518 sizeof(struct in_addr)); 1519 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1520 break; 1521 1522 case IPOPT_TS: 1523 #ifdef IPSTEALTH 1524 if (ipstealth && pass == 0) 1525 break; 1526 #endif 1527 code = cp - (u_char *)ip; 1528 if (optlen < 4 || optlen > 40) { 1529 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1530 goto bad; 1531 } 1532 if ((off = cp[IPOPT_OFFSET]) < 5) { 1533 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1534 goto bad; 1535 } 1536 if (off > optlen - (int)sizeof(int32_t)) { 1537 cp[IPOPT_OFFSET + 1] += (1 << 4); 1538 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1539 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1540 goto bad; 1541 } 1542 break; 1543 } 1544 off--; /* 0 origin */ 1545 sin = (struct in_addr *)(cp + off); 1546 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1547 1548 case IPOPT_TS_TSONLY: 1549 break; 1550 1551 case IPOPT_TS_TSANDADDR: 1552 if (off + sizeof(n_time) + 1553 sizeof(struct in_addr) > optlen) { 1554 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1555 goto bad; 1556 } 1557 ipaddr.sin_addr = dst; 1558 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1559 m->m_pkthdr.rcvif); 1560 if (ia == NULL) 1561 continue; 1562 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1563 sizeof(struct in_addr)); 1564 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1565 off += sizeof(struct in_addr); 1566 break; 1567 1568 case IPOPT_TS_PRESPEC: 1569 if (off + sizeof(n_time) + 1570 sizeof(struct in_addr) > optlen) { 1571 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1572 goto bad; 1573 } 1574 (void)memcpy(&ipaddr.sin_addr, sin, 1575 sizeof(struct in_addr)); 1576 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1577 continue; 1578 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1579 off += sizeof(struct in_addr); 1580 break; 1581 1582 default: 1583 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1584 goto bad; 1585 } 1586 ntime = iptime(); 1587 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1588 cp[IPOPT_OFFSET] += sizeof(n_time); 1589 } 1590 } 1591 if (forward && ipforwarding) { 1592 ip_forward(m, 1); 1593 return (1); 1594 } 1595 return (0); 1596 bad: 1597 icmp_error(m, type, code, 0, 0); 1598 ipstat.ips_badoptions++; 1599 return (1); 1600 } 1601 1602 /* 1603 * Given address of next destination (final or next hop), 1604 * return internet address info of interface to be used to get there. 1605 */ 1606 struct in_ifaddr * 1607 ip_rtaddr(dst) 1608 struct in_addr dst; 1609 { 1610 struct route sro; 1611 struct sockaddr_in *sin; 1612 struct in_ifaddr *ifa; 1613 1614 bzero(&sro, sizeof(sro)); 1615 sin = (struct sockaddr_in *)&sro.ro_dst; 1616 sin->sin_family = AF_INET; 1617 sin->sin_len = sizeof(*sin); 1618 sin->sin_addr = dst; 1619 rtalloc_ign(&sro, RTF_CLONING); 1620 1621 if (sro.ro_rt == NULL) 1622 return (NULL); 1623 1624 ifa = ifatoia(sro.ro_rt->rt_ifa); 1625 RTFREE(sro.ro_rt); 1626 return (ifa); 1627 } 1628 1629 /* 1630 * Save incoming source route for use in replies, 1631 * to be picked up later by ip_srcroute if the receiver is interested. 1632 */ 1633 static void 1634 save_rte(m, option, dst) 1635 struct mbuf *m; 1636 u_char *option; 1637 struct in_addr dst; 1638 { 1639 unsigned olen; 1640 struct ipopt_tag *opts; 1641 1642 opts = (struct ipopt_tag *)m_tag_get(PACKET_TAG_IPOPTIONS, 1643 sizeof(struct ipopt_tag), M_NOWAIT); 1644 if (opts == NULL) 1645 return; 1646 1647 olen = option[IPOPT_OLEN]; 1648 #ifdef DIAGNOSTIC 1649 if (ipprintfs) 1650 printf("save_rte: olen %d\n", olen); 1651 #endif 1652 if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) { 1653 m_tag_free((struct m_tag *)opts); 1654 return; 1655 } 1656 bcopy(option, opts->ip_srcrt.srcopt, olen); 1657 opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1658 opts->ip_srcrt.dst = dst; 1659 m_tag_prepend(m, (struct m_tag *)opts); 1660 } 1661 1662 /* 1663 * Retrieve incoming source route for use in replies, 1664 * in the same form used by setsockopt. 1665 * The first hop is placed before the options, will be removed later. 1666 */ 1667 struct mbuf * 1668 ip_srcroute(m0) 1669 struct mbuf *m0; 1670 { 1671 register struct in_addr *p, *q; 1672 register struct mbuf *m; 1673 struct ipopt_tag *opts; 1674 1675 opts = (struct ipopt_tag *)m_tag_find(m0, PACKET_TAG_IPOPTIONS, NULL); 1676 if (opts == NULL) 1677 return (NULL); 1678 1679 if (opts->ip_nhops == 0) 1680 return (NULL); 1681 m = m_get(M_DONTWAIT, MT_DATA); 1682 if (m == NULL) 1683 return (NULL); 1684 1685 #define OPTSIZ (sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt)) 1686 1687 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1688 m->m_len = opts->ip_nhops * sizeof(struct in_addr) + 1689 sizeof(struct in_addr) + OPTSIZ; 1690 #ifdef DIAGNOSTIC 1691 if (ipprintfs) 1692 printf("ip_srcroute: nhops %d mlen %d", opts->ip_nhops, m->m_len); 1693 #endif 1694 1695 /* 1696 * First save first hop for return route 1697 */ 1698 p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]); 1699 *(mtod(m, struct in_addr *)) = *p--; 1700 #ifdef DIAGNOSTIC 1701 if (ipprintfs) 1702 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1703 #endif 1704 1705 /* 1706 * Copy option fields and padding (nop) to mbuf. 1707 */ 1708 opts->ip_srcrt.nop = IPOPT_NOP; 1709 opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1710 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1711 &(opts->ip_srcrt.nop), OPTSIZ); 1712 q = (struct in_addr *)(mtod(m, caddr_t) + 1713 sizeof(struct in_addr) + OPTSIZ); 1714 #undef OPTSIZ 1715 /* 1716 * Record return path as an IP source route, 1717 * reversing the path (pointers are now aligned). 1718 */ 1719 while (p >= opts->ip_srcrt.route) { 1720 #ifdef DIAGNOSTIC 1721 if (ipprintfs) 1722 printf(" %lx", (u_long)ntohl(q->s_addr)); 1723 #endif 1724 *q++ = *p--; 1725 } 1726 /* 1727 * Last hop goes to final destination. 1728 */ 1729 *q = opts->ip_srcrt.dst; 1730 #ifdef DIAGNOSTIC 1731 if (ipprintfs) 1732 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1733 #endif 1734 m_tag_delete(m0, (struct m_tag *)opts); 1735 return (m); 1736 } 1737 1738 /* 1739 * Strip out IP options, at higher 1740 * level protocol in the kernel. 1741 * Second argument is buffer to which options 1742 * will be moved, and return value is their length. 1743 * XXX should be deleted; last arg currently ignored. 1744 */ 1745 void 1746 ip_stripoptions(m, mopt) 1747 register struct mbuf *m; 1748 struct mbuf *mopt; 1749 { 1750 register int i; 1751 struct ip *ip = mtod(m, struct ip *); 1752 register caddr_t opts; 1753 int olen; 1754 1755 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1756 opts = (caddr_t)(ip + 1); 1757 i = m->m_len - (sizeof (struct ip) + olen); 1758 bcopy(opts + olen, opts, (unsigned)i); 1759 m->m_len -= olen; 1760 if (m->m_flags & M_PKTHDR) 1761 m->m_pkthdr.len -= olen; 1762 ip->ip_v = IPVERSION; 1763 ip->ip_hl = sizeof(struct ip) >> 2; 1764 } 1765 1766 u_char inetctlerrmap[PRC_NCMDS] = { 1767 0, 0, 0, 0, 1768 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1769 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1770 EMSGSIZE, EHOSTUNREACH, 0, 0, 1771 0, 0, EHOSTUNREACH, 0, 1772 ENOPROTOOPT, ECONNREFUSED 1773 }; 1774 1775 /* 1776 * Forward a packet. If some error occurs return the sender 1777 * an icmp packet. Note we can't always generate a meaningful 1778 * icmp message because icmp doesn't have a large enough repertoire 1779 * of codes and types. 1780 * 1781 * If not forwarding, just drop the packet. This could be confusing 1782 * if ipforwarding was zero but some routing protocol was advancing 1783 * us as a gateway to somewhere. However, we must let the routing 1784 * protocol deal with that. 1785 * 1786 * The srcrt parameter indicates whether the packet is being forwarded 1787 * via a source route. 1788 */ 1789 void 1790 ip_forward(struct mbuf *m, int srcrt) 1791 { 1792 struct ip *ip = mtod(m, struct ip *); 1793 struct in_ifaddr *ia = NULL; 1794 struct mbuf *mcopy; 1795 struct in_addr dest; 1796 int error, type = 0, code = 0, mtu = 0; 1797 1798 #ifdef DIAGNOSTIC 1799 if (ipprintfs) 1800 printf("forward: src %lx dst %lx ttl %x\n", 1801 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1802 ip->ip_ttl); 1803 #endif 1804 1805 1806 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1807 ipstat.ips_cantforward++; 1808 m_freem(m); 1809 return; 1810 } 1811 #ifdef IPSTEALTH 1812 if (!ipstealth) { 1813 #endif 1814 if (ip->ip_ttl <= IPTTLDEC) { 1815 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1816 0, 0); 1817 return; 1818 } 1819 #ifdef IPSTEALTH 1820 } 1821 #endif 1822 1823 if (!srcrt && (ia = ip_rtaddr(ip->ip_dst)) == NULL) { 1824 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1825 return; 1826 } 1827 1828 /* 1829 * Save the IP header and at most 8 bytes of the payload, 1830 * in case we need to generate an ICMP message to the src. 1831 * 1832 * XXX this can be optimized a lot by saving the data in a local 1833 * buffer on the stack (72 bytes at most), and only allocating the 1834 * mbuf if really necessary. The vast majority of the packets 1835 * are forwarded without having to send an ICMP back (either 1836 * because unnecessary, or because rate limited), so we are 1837 * really we are wasting a lot of work here. 1838 * 1839 * We don't use m_copy() because it might return a reference 1840 * to a shared cluster. Both this function and ip_output() 1841 * assume exclusive access to the IP header in `m', so any 1842 * data in a cluster may change before we reach icmp_error(). 1843 */ 1844 MGET(mcopy, M_DONTWAIT, m->m_type); 1845 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1846 /* 1847 * It's probably ok if the pkthdr dup fails (because 1848 * the deep copy of the tag chain failed), but for now 1849 * be conservative and just discard the copy since 1850 * code below may some day want the tags. 1851 */ 1852 m_free(mcopy); 1853 mcopy = NULL; 1854 } 1855 if (mcopy != NULL) { 1856 mcopy->m_len = imin((ip->ip_hl << 2) + 8, 1857 (int)ip->ip_len); 1858 mcopy->m_pkthdr.len = mcopy->m_len; 1859 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1860 } 1861 1862 #ifdef IPSTEALTH 1863 if (!ipstealth) { 1864 #endif 1865 ip->ip_ttl -= IPTTLDEC; 1866 #ifdef IPSTEALTH 1867 } 1868 #endif 1869 1870 /* 1871 * If forwarding packet using same interface that it came in on, 1872 * perhaps should send a redirect to sender to shortcut a hop. 1873 * Only send redirect if source is sending directly to us, 1874 * and if packet was not source routed (or has any options). 1875 * Also, don't send redirect if forwarding using a default route 1876 * or a route modified by a redirect. 1877 */ 1878 dest.s_addr = 0; 1879 if (!srcrt && ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1880 struct sockaddr_in *sin; 1881 struct route ro; 1882 struct rtentry *rt; 1883 1884 bzero(&ro, sizeof(ro)); 1885 sin = (struct sockaddr_in *)&ro.ro_dst; 1886 sin->sin_family = AF_INET; 1887 sin->sin_len = sizeof(*sin); 1888 sin->sin_addr = ip->ip_dst; 1889 rtalloc_ign(&ro, RTF_CLONING); 1890 1891 rt = ro.ro_rt; 1892 1893 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1894 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1895 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1896 u_long src = ntohl(ip->ip_src.s_addr); 1897 1898 if (RTA(rt) && 1899 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1900 if (rt->rt_flags & RTF_GATEWAY) 1901 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1902 else 1903 dest.s_addr = ip->ip_dst.s_addr; 1904 /* Router requirements says to only send host redirects */ 1905 type = ICMP_REDIRECT; 1906 code = ICMP_REDIRECT_HOST; 1907 #ifdef DIAGNOSTIC 1908 if (ipprintfs) 1909 printf("redirect (%d) to %lx\n", code, (u_long)dest.s_addr); 1910 #endif 1911 } 1912 } 1913 if (rt) 1914 RTFREE(rt); 1915 } 1916 1917 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 1918 if (error) 1919 ipstat.ips_cantforward++; 1920 else { 1921 ipstat.ips_forward++; 1922 if (type) 1923 ipstat.ips_redirectsent++; 1924 else { 1925 if (mcopy) 1926 m_freem(mcopy); 1927 return; 1928 } 1929 } 1930 if (mcopy == NULL) 1931 return; 1932 1933 switch (error) { 1934 1935 case 0: /* forwarded, but need redirect */ 1936 /* type, code set above */ 1937 break; 1938 1939 case ENETUNREACH: /* shouldn't happen, checked above */ 1940 case EHOSTUNREACH: 1941 case ENETDOWN: 1942 case EHOSTDOWN: 1943 default: 1944 type = ICMP_UNREACH; 1945 code = ICMP_UNREACH_HOST; 1946 break; 1947 1948 case EMSGSIZE: 1949 type = ICMP_UNREACH; 1950 code = ICMP_UNREACH_NEEDFRAG; 1951 #if defined(IPSEC) || defined(FAST_IPSEC) 1952 /* 1953 * If the packet is routed over IPsec tunnel, tell the 1954 * originator the tunnel MTU. 1955 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1956 * XXX quickhack!!! 1957 */ 1958 { 1959 struct secpolicy *sp = NULL; 1960 int ipsecerror; 1961 int ipsechdr; 1962 struct route *ro; 1963 1964 #ifdef IPSEC 1965 sp = ipsec4_getpolicybyaddr(mcopy, 1966 IPSEC_DIR_OUTBOUND, 1967 IP_FORWARDING, 1968 &ipsecerror); 1969 #else /* FAST_IPSEC */ 1970 sp = ipsec_getpolicybyaddr(mcopy, 1971 IPSEC_DIR_OUTBOUND, 1972 IP_FORWARDING, 1973 &ipsecerror); 1974 #endif 1975 if (sp != NULL) { 1976 /* count IPsec header size */ 1977 ipsechdr = ipsec4_hdrsiz(mcopy, 1978 IPSEC_DIR_OUTBOUND, 1979 NULL); 1980 1981 /* 1982 * find the correct route for outer IPv4 1983 * header, compute tunnel MTU. 1984 */ 1985 if (sp->req != NULL 1986 && sp->req->sav != NULL 1987 && sp->req->sav->sah != NULL) { 1988 ro = &sp->req->sav->sah->sa_route; 1989 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1990 mtu = 1991 ro->ro_rt->rt_rmx.rmx_mtu ? 1992 ro->ro_rt->rt_rmx.rmx_mtu : 1993 ro->ro_rt->rt_ifp->if_mtu; 1994 mtu -= ipsechdr; 1995 } 1996 } 1997 1998 #ifdef IPSEC 1999 key_freesp(sp); 2000 #else /* FAST_IPSEC */ 2001 KEY_FREESP(&sp); 2002 #endif 2003 ipstat.ips_cantfrag++; 2004 break; 2005 } 2006 } 2007 #endif /*IPSEC || FAST_IPSEC*/ 2008 /* 2009 * If the MTU wasn't set before use the interface mtu or 2010 * fall back to the next smaller mtu step compared to the 2011 * current packet size. 2012 */ 2013 if (mtu == 0) { 2014 if (ia != NULL) 2015 mtu = ia->ia_ifp->if_mtu; 2016 else 2017 mtu = ip_next_mtu(ip->ip_len, 0); 2018 } 2019 ipstat.ips_cantfrag++; 2020 break; 2021 2022 case ENOBUFS: 2023 /* 2024 * A router should not generate ICMP_SOURCEQUENCH as 2025 * required in RFC1812 Requirements for IP Version 4 Routers. 2026 * Source quench could be a big problem under DoS attacks, 2027 * or if the underlying interface is rate-limited. 2028 * Those who need source quench packets may re-enable them 2029 * via the net.inet.ip.sendsourcequench sysctl. 2030 */ 2031 if (ip_sendsourcequench == 0) { 2032 m_freem(mcopy); 2033 return; 2034 } else { 2035 type = ICMP_SOURCEQUENCH; 2036 code = 0; 2037 } 2038 break; 2039 2040 case EACCES: /* ipfw denied packet */ 2041 m_freem(mcopy); 2042 return; 2043 } 2044 icmp_error(mcopy, type, code, dest.s_addr, mtu); 2045 } 2046 2047 void 2048 ip_savecontrol(inp, mp, ip, m) 2049 register struct inpcb *inp; 2050 register struct mbuf **mp; 2051 register struct ip *ip; 2052 register struct mbuf *m; 2053 { 2054 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 2055 struct bintime bt; 2056 2057 bintime(&bt); 2058 if (inp->inp_socket->so_options & SO_BINTIME) { 2059 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 2060 SCM_BINTIME, SOL_SOCKET); 2061 if (*mp) 2062 mp = &(*mp)->m_next; 2063 } 2064 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2065 struct timeval tv; 2066 2067 bintime2timeval(&bt, &tv); 2068 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2069 SCM_TIMESTAMP, SOL_SOCKET); 2070 if (*mp) 2071 mp = &(*mp)->m_next; 2072 } 2073 } 2074 if (inp->inp_flags & INP_RECVDSTADDR) { 2075 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2076 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2077 if (*mp) 2078 mp = &(*mp)->m_next; 2079 } 2080 if (inp->inp_flags & INP_RECVTTL) { 2081 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2082 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2083 if (*mp) 2084 mp = &(*mp)->m_next; 2085 } 2086 #ifdef notyet 2087 /* XXX 2088 * Moving these out of udp_input() made them even more broken 2089 * than they already were. 2090 */ 2091 /* options were tossed already */ 2092 if (inp->inp_flags & INP_RECVOPTS) { 2093 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2094 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2095 if (*mp) 2096 mp = &(*mp)->m_next; 2097 } 2098 /* ip_srcroute doesn't do what we want here, need to fix */ 2099 if (inp->inp_flags & INP_RECVRETOPTS) { 2100 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 2101 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2102 if (*mp) 2103 mp = &(*mp)->m_next; 2104 } 2105 #endif 2106 if (inp->inp_flags & INP_RECVIF) { 2107 struct ifnet *ifp; 2108 struct sdlbuf { 2109 struct sockaddr_dl sdl; 2110 u_char pad[32]; 2111 } sdlbuf; 2112 struct sockaddr_dl *sdp; 2113 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2114 2115 if (((ifp = m->m_pkthdr.rcvif)) 2116 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2117 sdp = (struct sockaddr_dl *) 2118 (ifaddr_byindex(ifp->if_index)->ifa_addr); 2119 /* 2120 * Change our mind and don't try copy. 2121 */ 2122 if ((sdp->sdl_family != AF_LINK) 2123 || (sdp->sdl_len > sizeof(sdlbuf))) { 2124 goto makedummy; 2125 } 2126 bcopy(sdp, sdl2, sdp->sdl_len); 2127 } else { 2128 makedummy: 2129 sdl2->sdl_len 2130 = offsetof(struct sockaddr_dl, sdl_data[0]); 2131 sdl2->sdl_family = AF_LINK; 2132 sdl2->sdl_index = 0; 2133 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2134 } 2135 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2136 IP_RECVIF, IPPROTO_IP); 2137 if (*mp) 2138 mp = &(*mp)->m_next; 2139 } 2140 } 2141 2142 /* 2143 * XXX these routines are called from the upper part of the kernel. 2144 * They need to be locked when we remove Giant. 2145 * 2146 * They could also be moved to ip_mroute.c, since all the RSVP 2147 * handling is done there already. 2148 */ 2149 static int ip_rsvp_on; 2150 struct socket *ip_rsvpd; 2151 int 2152 ip_rsvp_init(struct socket *so) 2153 { 2154 if (so->so_type != SOCK_RAW || 2155 so->so_proto->pr_protocol != IPPROTO_RSVP) 2156 return EOPNOTSUPP; 2157 2158 if (ip_rsvpd != NULL) 2159 return EADDRINUSE; 2160 2161 ip_rsvpd = so; 2162 /* 2163 * This may seem silly, but we need to be sure we don't over-increment 2164 * the RSVP counter, in case something slips up. 2165 */ 2166 if (!ip_rsvp_on) { 2167 ip_rsvp_on = 1; 2168 rsvp_on++; 2169 } 2170 2171 return 0; 2172 } 2173 2174 int 2175 ip_rsvp_done(void) 2176 { 2177 ip_rsvpd = NULL; 2178 /* 2179 * This may seem silly, but we need to be sure we don't over-decrement 2180 * the RSVP counter, in case something slips up. 2181 */ 2182 if (ip_rsvp_on) { 2183 ip_rsvp_on = 0; 2184 rsvp_on--; 2185 } 2186 return 0; 2187 } 2188 2189 void 2190 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 2191 { 2192 if (rsvp_input_p) { /* call the real one if loaded */ 2193 rsvp_input_p(m, off); 2194 return; 2195 } 2196 2197 /* Can still get packets with rsvp_on = 0 if there is a local member 2198 * of the group to which the RSVP packet is addressed. But in this 2199 * case we want to throw the packet away. 2200 */ 2201 2202 if (!rsvp_on) { 2203 m_freem(m); 2204 return; 2205 } 2206 2207 if (ip_rsvpd != NULL) { 2208 rip_input(m, off); 2209 return; 2210 } 2211 /* Drop the packet */ 2212 m_freem(m); 2213 }
Cache object: 4e7ceb0332ac41576d959069518f716d
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