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 <netinet/ip_options.h> 70 #include <machine/in_cksum.h> 71 #ifdef DEV_CARP 72 #include <netinet/ip_carp.h> 73 #endif 74 #if defined(IPSEC) || defined(FAST_IPSEC) 75 #include <netinet/ip_ipsec.h> 76 #endif /* IPSEC */ 77 78 #include <sys/socketvar.h> 79 80 /* XXX: Temporary until ipfw_ether and ipfw_bridge are converted. */ 81 #include <netinet/ip_fw.h> 82 #include <netinet/ip_dummynet.h> 83 84 int rsvp_on = 0; 85 86 int ipforwarding = 0; 87 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 88 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 89 90 static int ipsendredirects = 1; /* XXX */ 91 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 92 &ipsendredirects, 0, "Enable sending IP redirects"); 93 94 int ip_defttl = IPDEFTTL; 95 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 96 &ip_defttl, 0, "Maximum TTL on IP packets"); 97 98 static int ip_keepfaith = 0; 99 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 100 &ip_keepfaith, 0, 101 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 102 103 static int ip_sendsourcequench = 0; 104 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 105 &ip_sendsourcequench, 0, 106 "Enable the transmission of source quench packets"); 107 108 int ip_do_randomid = 0; 109 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 110 &ip_do_randomid, 0, 111 "Assign random ip_id values"); 112 113 /* 114 * XXX - Setting ip_checkinterface mostly implements the receive side of 115 * the Strong ES model described in RFC 1122, but since the routing table 116 * and transmit implementation do not implement the Strong ES model, 117 * setting this to 1 results in an odd hybrid. 118 * 119 * XXX - ip_checkinterface currently must be disabled if you use ipnat 120 * to translate the destination address to another local interface. 121 * 122 * XXX - ip_checkinterface must be disabled if you add IP aliases 123 * to the loopback interface instead of the interface where the 124 * packets for those addresses are received. 125 */ 126 static int ip_checkinterface = 0; 127 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 128 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 129 130 struct pfil_head inet_pfil_hook; /* Packet filter hooks */ 131 132 static struct ifqueue ipintrq; 133 static int ipqmaxlen = IFQ_MAXLEN; 134 135 extern struct domain inetdomain; 136 extern struct protosw inetsw[]; 137 u_char ip_protox[IPPROTO_MAX]; 138 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 139 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 140 u_long in_ifaddrhmask; /* mask for hash table */ 141 142 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 143 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 144 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 145 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 146 147 struct ipstat ipstat; 148 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 149 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 150 151 /* 152 * IP datagram reassembly. 153 */ 154 #define IPREASS_NHASH_LOG2 6 155 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 156 #define IPREASS_HMASK (IPREASS_NHASH - 1) 157 #define IPREASS_HASH(x,y) \ 158 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 159 160 static uma_zone_t ipq_zone; 161 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 162 static struct mtx ipqlock; 163 164 #define IPQ_LOCK() mtx_lock(&ipqlock) 165 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 166 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 167 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 168 169 static void maxnipq_update(void); 170 171 static int maxnipq; /* Administrative limit on # reass queues. */ 172 static int nipq = 0; /* Total # of reass queues */ 173 SYSCTL_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, &nipq, 0, 174 "Current number of IPv4 fragment reassembly queue entries"); 175 176 static int maxfragsperpacket; 177 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 178 &maxfragsperpacket, 0, 179 "Maximum number of IPv4 fragments allowed per packet"); 180 181 struct callout ipport_tick_callout; 182 183 #ifdef IPCTL_DEFMTU 184 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 185 &ip_mtu, 0, "Default MTU"); 186 #endif 187 188 #ifdef IPSTEALTH 189 int ipstealth = 0; 190 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 191 &ipstealth, 0, ""); 192 #endif 193 194 /* 195 * ipfw_ether and ipfw_bridge hooks. 196 * XXX: Temporary until those are converted to pfil_hooks as well. 197 */ 198 ip_fw_chk_t *ip_fw_chk_ptr = NULL; 199 ip_dn_io_t *ip_dn_io_ptr = NULL; 200 int fw_enable = 1; 201 int fw_one_pass = 1; 202 203 static void ip_freef(struct ipqhead *, struct ipq *); 204 205 /* 206 * IP initialization: fill in IP protocol switch table. 207 * All protocols not implemented in kernel go to raw IP protocol handler. 208 */ 209 void 210 ip_init() 211 { 212 register struct protosw *pr; 213 register int i; 214 215 TAILQ_INIT(&in_ifaddrhead); 216 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 217 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 218 if (pr == NULL) 219 panic("ip_init: PF_INET not found"); 220 221 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 222 for (i = 0; i < IPPROTO_MAX; i++) 223 ip_protox[i] = pr - inetsw; 224 /* 225 * Cycle through IP protocols and put them into the appropriate place 226 * in ip_protox[]. 227 */ 228 for (pr = inetdomain.dom_protosw; 229 pr < inetdomain.dom_protoswNPROTOSW; pr++) 230 if (pr->pr_domain->dom_family == PF_INET && 231 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 232 /* Be careful to only index valid IP protocols. */ 233 if (pr->pr_protocol < IPPROTO_MAX) 234 ip_protox[pr->pr_protocol] = pr - inetsw; 235 } 236 237 /* Initialize packet filter hooks. */ 238 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 239 inet_pfil_hook.ph_af = AF_INET; 240 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 241 printf("%s: WARNING: unable to register pfil hook, " 242 "error %d\n", __func__, i); 243 244 /* Initialize IP reassembly queue. */ 245 IPQ_LOCK_INIT(); 246 for (i = 0; i < IPREASS_NHASH; i++) 247 TAILQ_INIT(&ipq[i]); 248 maxnipq = nmbclusters / 32; 249 maxfragsperpacket = 16; 250 ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 251 NULL, UMA_ALIGN_PTR, 0); 252 maxnipq_update(); 253 254 /* Start ipport_tick. */ 255 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE); 256 ipport_tick(NULL); 257 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL, 258 SHUTDOWN_PRI_DEFAULT); 259 260 /* Initialize various other remaining things. */ 261 ip_id = time_second & 0xffff; 262 ipintrq.ifq_maxlen = ipqmaxlen; 263 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 264 netisr_register(NETISR_IP, ip_input, &ipintrq, NETISR_MPSAFE); 265 } 266 267 void ip_fini(xtp) 268 void *xtp; 269 { 270 callout_stop(&ipport_tick_callout); 271 } 272 273 /* 274 * Ip input routine. Checksum and byte swap header. If fragmented 275 * try to reassemble. Process options. Pass to next level. 276 */ 277 void 278 ip_input(struct mbuf *m) 279 { 280 struct ip *ip = NULL; 281 struct in_ifaddr *ia = NULL; 282 struct ifaddr *ifa; 283 int checkif, hlen = 0; 284 u_short sum; 285 int dchg = 0; /* dest changed after fw */ 286 struct in_addr odst; /* original dst address */ 287 288 M_ASSERTPKTHDR(m); 289 290 if (m->m_flags & M_FASTFWD_OURS) { 291 /* 292 * Firewall or NAT changed destination to local. 293 * We expect ip_len and ip_off to be in host byte order. 294 */ 295 m->m_flags &= ~M_FASTFWD_OURS; 296 /* Set up some basics that will be used later. */ 297 ip = mtod(m, struct ip *); 298 hlen = ip->ip_hl << 2; 299 goto ours; 300 } 301 302 ipstat.ips_total++; 303 304 if (m->m_pkthdr.len < sizeof(struct ip)) 305 goto tooshort; 306 307 if (m->m_len < sizeof (struct ip) && 308 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 309 ipstat.ips_toosmall++; 310 return; 311 } 312 ip = mtod(m, struct ip *); 313 314 if (ip->ip_v != IPVERSION) { 315 ipstat.ips_badvers++; 316 goto bad; 317 } 318 319 hlen = ip->ip_hl << 2; 320 if (hlen < sizeof(struct ip)) { /* minimum header length */ 321 ipstat.ips_badhlen++; 322 goto bad; 323 } 324 if (hlen > m->m_len) { 325 if ((m = m_pullup(m, hlen)) == NULL) { 326 ipstat.ips_badhlen++; 327 return; 328 } 329 ip = mtod(m, struct ip *); 330 } 331 332 /* 127/8 must not appear on wire - RFC1122 */ 333 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 334 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 335 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 336 ipstat.ips_badaddr++; 337 goto bad; 338 } 339 } 340 341 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 342 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 343 } else { 344 if (hlen == sizeof(struct ip)) { 345 sum = in_cksum_hdr(ip); 346 } else { 347 sum = in_cksum(m, hlen); 348 } 349 } 350 if (sum) { 351 ipstat.ips_badsum++; 352 goto bad; 353 } 354 355 #ifdef ALTQ 356 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 357 /* packet is dropped by traffic conditioner */ 358 return; 359 #endif 360 361 /* 362 * Convert fields to host representation. 363 */ 364 ip->ip_len = ntohs(ip->ip_len); 365 if (ip->ip_len < hlen) { 366 ipstat.ips_badlen++; 367 goto bad; 368 } 369 ip->ip_off = ntohs(ip->ip_off); 370 371 /* 372 * Check that the amount of data in the buffers 373 * is as at least much as the IP header would have us expect. 374 * Trim mbufs if longer than we expect. 375 * Drop packet if shorter than we expect. 376 */ 377 if (m->m_pkthdr.len < ip->ip_len) { 378 tooshort: 379 ipstat.ips_tooshort++; 380 goto bad; 381 } 382 if (m->m_pkthdr.len > ip->ip_len) { 383 if (m->m_len == m->m_pkthdr.len) { 384 m->m_len = ip->ip_len; 385 m->m_pkthdr.len = ip->ip_len; 386 } else 387 m_adj(m, ip->ip_len - m->m_pkthdr.len); 388 } 389 #if defined(IPSEC) || defined(FAST_IPSEC) 390 /* 391 * Bypass packet filtering for packets from a tunnel (gif). 392 */ 393 if (ip_ipsec_filtergif(m)) 394 goto passin; 395 #endif /* IPSEC */ 396 397 /* 398 * Run through list of hooks for input packets. 399 * 400 * NB: Beware of the destination address changing (e.g. 401 * by NAT rewriting). When this happens, tell 402 * ip_forward to do the right thing. 403 */ 404 405 /* Jump over all PFIL processing if hooks are not active. */ 406 if (!PFIL_HOOKED(&inet_pfil_hook)) 407 goto passin; 408 409 odst = ip->ip_dst; 410 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 411 PFIL_IN, NULL) != 0) 412 return; 413 if (m == NULL) /* consumed by filter */ 414 return; 415 416 ip = mtod(m, struct ip *); 417 dchg = (odst.s_addr != ip->ip_dst.s_addr); 418 419 #ifdef IPFIREWALL_FORWARD 420 if (m->m_flags & M_FASTFWD_OURS) { 421 m->m_flags &= ~M_FASTFWD_OURS; 422 goto ours; 423 } 424 #ifndef IPFIREWALL_FORWARD_EXTENDED 425 dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL); 426 #else 427 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 428 /* 429 * Directly ship on the packet. This allows to forward packets 430 * that were destined for us to some other directly connected 431 * host. 432 */ 433 ip_forward(m, dchg); 434 return; 435 } 436 #endif /* IPFIREWALL_FORWARD_EXTENDED */ 437 #endif /* IPFIREWALL_FORWARD */ 438 439 passin: 440 /* 441 * Process options and, if not destined for us, 442 * ship it on. ip_dooptions returns 1 when an 443 * error was detected (causing an icmp message 444 * to be sent and the original packet to be freed). 445 */ 446 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 447 return; 448 449 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 450 * matter if it is destined to another node, or whether it is 451 * a multicast one, RSVP wants it! and prevents it from being forwarded 452 * anywhere else. Also checks if the rsvp daemon is running before 453 * grabbing the packet. 454 */ 455 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 456 goto ours; 457 458 /* 459 * Check our list of addresses, to see if the packet is for us. 460 * If we don't have any addresses, assume any unicast packet 461 * we receive might be for us (and let the upper layers deal 462 * with it). 463 */ 464 if (TAILQ_EMPTY(&in_ifaddrhead) && 465 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 466 goto ours; 467 468 /* 469 * Enable a consistency check between the destination address 470 * and the arrival interface for a unicast packet (the RFC 1122 471 * strong ES model) if IP forwarding is disabled and the packet 472 * is not locally generated and the packet is not subject to 473 * 'ipfw fwd'. 474 * 475 * XXX - Checking also should be disabled if the destination 476 * address is ipnat'ed to a different interface. 477 * 478 * XXX - Checking is incompatible with IP aliases added 479 * to the loopback interface instead of the interface where 480 * the packets are received. 481 * 482 * XXX - This is the case for carp vhost IPs as well so we 483 * insert a workaround. If the packet got here, we already 484 * checked with carp_iamatch() and carp_forus(). 485 */ 486 checkif = ip_checkinterface && (ipforwarding == 0) && 487 m->m_pkthdr.rcvif != NULL && 488 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 489 #ifdef DEV_CARP 490 !m->m_pkthdr.rcvif->if_carp && 491 #endif 492 (dchg == 0); 493 494 /* 495 * Check for exact addresses in the hash bucket. 496 */ 497 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 498 /* 499 * If the address matches, verify that the packet 500 * arrived via the correct interface if checking is 501 * enabled. 502 */ 503 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 504 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 505 goto ours; 506 } 507 /* 508 * Check for broadcast addresses. 509 * 510 * Only accept broadcast packets that arrive via the matching 511 * interface. Reception of forwarded directed broadcasts would 512 * be handled via ip_forward() and ether_output() with the loopback 513 * into the stack for SIMPLEX interfaces handled by ether_output(). 514 */ 515 if (m->m_pkthdr.rcvif != NULL && 516 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 517 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 518 if (ifa->ifa_addr->sa_family != AF_INET) 519 continue; 520 ia = ifatoia(ifa); 521 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 522 ip->ip_dst.s_addr) 523 goto ours; 524 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 525 goto ours; 526 #ifdef BOOTP_COMPAT 527 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 528 goto ours; 529 #endif 530 } 531 } 532 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 533 struct in_multi *inm; 534 if (ip_mrouter) { 535 /* 536 * If we are acting as a multicast router, all 537 * incoming multicast packets are passed to the 538 * kernel-level multicast forwarding function. 539 * The packet is returned (relatively) intact; if 540 * ip_mforward() returns a non-zero value, the packet 541 * must be discarded, else it may be accepted below. 542 */ 543 if (ip_mforward && 544 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 545 ipstat.ips_cantforward++; 546 m_freem(m); 547 return; 548 } 549 550 /* 551 * The process-level routing daemon needs to receive 552 * all multicast IGMP packets, whether or not this 553 * host belongs to their destination groups. 554 */ 555 if (ip->ip_p == IPPROTO_IGMP) 556 goto ours; 557 ipstat.ips_forward++; 558 } 559 /* 560 * See if we belong to the destination multicast group on the 561 * arrival interface. 562 */ 563 IN_MULTI_LOCK(); 564 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 565 IN_MULTI_UNLOCK(); 566 if (inm == NULL) { 567 ipstat.ips_notmember++; 568 m_freem(m); 569 return; 570 } 571 goto ours; 572 } 573 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 574 goto ours; 575 if (ip->ip_dst.s_addr == INADDR_ANY) 576 goto ours; 577 578 /* 579 * FAITH(Firewall Aided Internet Translator) 580 */ 581 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 582 if (ip_keepfaith) { 583 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 584 goto ours; 585 } 586 m_freem(m); 587 return; 588 } 589 590 /* 591 * Not for us; forward if possible and desirable. 592 */ 593 if (ipforwarding == 0) { 594 ipstat.ips_cantforward++; 595 m_freem(m); 596 } else { 597 #if defined(IPSEC) || defined(FAST_IPSEC) 598 if (ip_ipsec_fwd(m)) 599 goto bad; 600 #endif /* IPSEC */ 601 ip_forward(m, dchg); 602 } 603 return; 604 605 ours: 606 #ifdef IPSTEALTH 607 /* 608 * IPSTEALTH: Process non-routing options only 609 * if the packet is destined for us. 610 */ 611 if (ipstealth && hlen > sizeof (struct ip) && 612 ip_dooptions(m, 1)) 613 return; 614 #endif /* IPSTEALTH */ 615 616 /* Count the packet in the ip address stats */ 617 if (ia != NULL) { 618 ia->ia_ifa.if_ipackets++; 619 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 620 } 621 622 /* 623 * Attempt reassembly; if it succeeds, proceed. 624 * ip_reass() will return a different mbuf. 625 */ 626 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 627 m = ip_reass(m); 628 if (m == NULL) 629 return; 630 ip = mtod(m, struct ip *); 631 /* Get the header length of the reassembled packet */ 632 hlen = ip->ip_hl << 2; 633 } 634 635 /* 636 * Further protocols expect the packet length to be w/o the 637 * IP header. 638 */ 639 ip->ip_len -= hlen; 640 641 #if defined(IPSEC) || defined(FAST_IPSEC) 642 /* 643 * enforce IPsec policy checking if we are seeing last header. 644 * note that we do not visit this with protocols with pcb layer 645 * code - like udp/tcp/raw ip. 646 */ 647 if (ip_ipsec_input(m)) 648 goto bad; 649 #endif /* IPSEC */ 650 651 /* 652 * Switch out to protocol's input routine. 653 */ 654 ipstat.ips_delivered++; 655 656 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 657 return; 658 bad: 659 m_freem(m); 660 } 661 662 /* 663 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 664 * max has slightly different semantics than the sysctl, for historical 665 * reasons. 666 */ 667 static void 668 maxnipq_update(void) 669 { 670 671 /* 672 * -1 for unlimited allocation. 673 */ 674 if (maxnipq < 0) 675 uma_zone_set_max(ipq_zone, 0); 676 /* 677 * Positive number for specific bound. 678 */ 679 if (maxnipq > 0) 680 uma_zone_set_max(ipq_zone, maxnipq); 681 /* 682 * Zero specifies no further fragment queue allocation -- set the 683 * bound very low, but rely on implementation elsewhere to actually 684 * prevent allocation and reclaim current queues. 685 */ 686 if (maxnipq == 0) 687 uma_zone_set_max(ipq_zone, 1); 688 } 689 690 static int 691 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 692 { 693 int error, i; 694 695 i = maxnipq; 696 error = sysctl_handle_int(oidp, &i, 0, req); 697 if (error || !req->newptr) 698 return (error); 699 700 /* 701 * XXXRW: Might be a good idea to sanity check the argument and place 702 * an extreme upper bound. 703 */ 704 if (i < -1) 705 return (EINVAL); 706 maxnipq = i; 707 maxnipq_update(); 708 return (0); 709 } 710 711 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 712 NULL, 0, sysctl_maxnipq, "I", 713 "Maximum number of IPv4 fragment reassembly queue entries"); 714 715 /* 716 * Take incoming datagram fragment and try to reassemble it into 717 * whole datagram. If the argument is the first fragment or one 718 * in between the function will return NULL and store the mbuf 719 * in the fragment chain. If the argument is the last fragment 720 * the packet will be reassembled and the pointer to the new 721 * mbuf returned for further processing. Only m_tags attached 722 * to the first packet/fragment are preserved. 723 * The IP header is *NOT* adjusted out of iplen. 724 */ 725 726 struct mbuf * 727 ip_reass(struct mbuf *m) 728 { 729 struct ip *ip; 730 struct mbuf *p, *q, *nq, *t; 731 struct ipq *fp = NULL; 732 struct ipqhead *head; 733 int i, hlen, next; 734 u_int8_t ecn, ecn0; 735 u_short hash; 736 737 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 738 if (maxnipq == 0 || maxfragsperpacket == 0) { 739 ipstat.ips_fragments++; 740 ipstat.ips_fragdropped++; 741 m_freem(m); 742 return (NULL); 743 } 744 745 ip = mtod(m, struct ip *); 746 hlen = ip->ip_hl << 2; 747 748 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 749 head = &ipq[hash]; 750 IPQ_LOCK(); 751 752 /* 753 * Look for queue of fragments 754 * of this datagram. 755 */ 756 TAILQ_FOREACH(fp, head, ipq_list) 757 if (ip->ip_id == fp->ipq_id && 758 ip->ip_src.s_addr == fp->ipq_src.s_addr && 759 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 760 #ifdef MAC 761 mac_fragment_match(m, fp) && 762 #endif 763 ip->ip_p == fp->ipq_p) 764 goto found; 765 766 fp = NULL; 767 768 /* 769 * Attempt to trim the number of allocated fragment queues if it 770 * exceeds the administrative limit. 771 */ 772 if ((nipq > maxnipq) && (maxnipq > 0)) { 773 /* 774 * drop something from the tail of the current queue 775 * before proceeding further 776 */ 777 struct ipq *q = TAILQ_LAST(head, ipqhead); 778 if (q == NULL) { /* gak */ 779 for (i = 0; i < IPREASS_NHASH; i++) { 780 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 781 if (r) { 782 ipstat.ips_fragtimeout += r->ipq_nfrags; 783 ip_freef(&ipq[i], r); 784 break; 785 } 786 } 787 } else { 788 ipstat.ips_fragtimeout += q->ipq_nfrags; 789 ip_freef(head, q); 790 } 791 } 792 793 found: 794 /* 795 * Adjust ip_len to not reflect header, 796 * convert offset of this to bytes. 797 */ 798 ip->ip_len -= hlen; 799 if (ip->ip_off & IP_MF) { 800 /* 801 * Make sure that fragments have a data length 802 * that's a non-zero multiple of 8 bytes. 803 */ 804 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 805 ipstat.ips_toosmall++; /* XXX */ 806 goto dropfrag; 807 } 808 m->m_flags |= M_FRAG; 809 } else 810 m->m_flags &= ~M_FRAG; 811 ip->ip_off <<= 3; 812 813 814 /* 815 * Attempt reassembly; if it succeeds, proceed. 816 * ip_reass() will return a different mbuf. 817 */ 818 ipstat.ips_fragments++; 819 m->m_pkthdr.header = ip; 820 821 /* Previous ip_reass() started here. */ 822 /* 823 * Presence of header sizes in mbufs 824 * would confuse code below. 825 */ 826 m->m_data += hlen; 827 m->m_len -= hlen; 828 829 /* 830 * If first fragment to arrive, create a reassembly queue. 831 */ 832 if (fp == NULL) { 833 fp = uma_zalloc(ipq_zone, M_NOWAIT); 834 if (fp == NULL) 835 goto dropfrag; 836 #ifdef MAC 837 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 838 uma_zfree(ipq_zone, fp); 839 goto dropfrag; 840 } 841 mac_create_ipq(m, fp); 842 #endif 843 TAILQ_INSERT_HEAD(head, fp, ipq_list); 844 nipq++; 845 fp->ipq_nfrags = 1; 846 fp->ipq_ttl = IPFRAGTTL; 847 fp->ipq_p = ip->ip_p; 848 fp->ipq_id = ip->ip_id; 849 fp->ipq_src = ip->ip_src; 850 fp->ipq_dst = ip->ip_dst; 851 fp->ipq_frags = m; 852 m->m_nextpkt = NULL; 853 goto done; 854 } else { 855 fp->ipq_nfrags++; 856 #ifdef MAC 857 mac_update_ipq(m, fp); 858 #endif 859 } 860 861 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 862 863 /* 864 * Handle ECN by comparing this segment with the first one; 865 * if CE is set, do not lose CE. 866 * drop if CE and not-ECT are mixed for the same packet. 867 */ 868 ecn = ip->ip_tos & IPTOS_ECN_MASK; 869 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 870 if (ecn == IPTOS_ECN_CE) { 871 if (ecn0 == IPTOS_ECN_NOTECT) 872 goto dropfrag; 873 if (ecn0 != IPTOS_ECN_CE) 874 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 875 } 876 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 877 goto dropfrag; 878 879 /* 880 * Find a segment which begins after this one does. 881 */ 882 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 883 if (GETIP(q)->ip_off > ip->ip_off) 884 break; 885 886 /* 887 * If there is a preceding segment, it may provide some of 888 * our data already. If so, drop the data from the incoming 889 * segment. If it provides all of our data, drop us, otherwise 890 * stick new segment in the proper place. 891 * 892 * If some of the data is dropped from the the preceding 893 * segment, then it's checksum is invalidated. 894 */ 895 if (p) { 896 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 897 if (i > 0) { 898 if (i >= ip->ip_len) 899 goto dropfrag; 900 m_adj(m, i); 901 m->m_pkthdr.csum_flags = 0; 902 ip->ip_off += i; 903 ip->ip_len -= i; 904 } 905 m->m_nextpkt = p->m_nextpkt; 906 p->m_nextpkt = m; 907 } else { 908 m->m_nextpkt = fp->ipq_frags; 909 fp->ipq_frags = m; 910 } 911 912 /* 913 * While we overlap succeeding segments trim them or, 914 * if they are completely covered, dequeue them. 915 */ 916 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 917 q = nq) { 918 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 919 if (i < GETIP(q)->ip_len) { 920 GETIP(q)->ip_len -= i; 921 GETIP(q)->ip_off += i; 922 m_adj(q, i); 923 q->m_pkthdr.csum_flags = 0; 924 break; 925 } 926 nq = q->m_nextpkt; 927 m->m_nextpkt = nq; 928 ipstat.ips_fragdropped++; 929 fp->ipq_nfrags--; 930 m_freem(q); 931 } 932 933 /* 934 * Check for complete reassembly and perform frag per packet 935 * limiting. 936 * 937 * Frag limiting is performed here so that the nth frag has 938 * a chance to complete the packet before we drop the packet. 939 * As a result, n+1 frags are actually allowed per packet, but 940 * only n will ever be stored. (n = maxfragsperpacket.) 941 * 942 */ 943 next = 0; 944 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 945 if (GETIP(q)->ip_off != next) { 946 if (fp->ipq_nfrags > maxfragsperpacket) { 947 ipstat.ips_fragdropped += fp->ipq_nfrags; 948 ip_freef(head, fp); 949 } 950 goto done; 951 } 952 next += GETIP(q)->ip_len; 953 } 954 /* Make sure the last packet didn't have the IP_MF flag */ 955 if (p->m_flags & M_FRAG) { 956 if (fp->ipq_nfrags > maxfragsperpacket) { 957 ipstat.ips_fragdropped += fp->ipq_nfrags; 958 ip_freef(head, fp); 959 } 960 goto done; 961 } 962 963 /* 964 * Reassembly is complete. Make sure the packet is a sane size. 965 */ 966 q = fp->ipq_frags; 967 ip = GETIP(q); 968 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 969 ipstat.ips_toolong++; 970 ipstat.ips_fragdropped += fp->ipq_nfrags; 971 ip_freef(head, fp); 972 goto done; 973 } 974 975 /* 976 * Concatenate fragments. 977 */ 978 m = q; 979 t = m->m_next; 980 m->m_next = NULL; 981 m_cat(m, t); 982 nq = q->m_nextpkt; 983 q->m_nextpkt = NULL; 984 for (q = nq; q != NULL; q = nq) { 985 nq = q->m_nextpkt; 986 q->m_nextpkt = NULL; 987 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 988 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 989 m_cat(m, q); 990 } 991 #ifdef MAC 992 mac_create_datagram_from_ipq(fp, m); 993 mac_destroy_ipq(fp); 994 #endif 995 996 /* 997 * Create header for new ip packet by modifying header of first 998 * packet; dequeue and discard fragment reassembly header. 999 * Make header visible. 1000 */ 1001 ip->ip_len = (ip->ip_hl << 2) + next; 1002 ip->ip_src = fp->ipq_src; 1003 ip->ip_dst = fp->ipq_dst; 1004 TAILQ_REMOVE(head, fp, ipq_list); 1005 nipq--; 1006 uma_zfree(ipq_zone, fp); 1007 m->m_len += (ip->ip_hl << 2); 1008 m->m_data -= (ip->ip_hl << 2); 1009 /* some debugging cruft by sklower, below, will go away soon */ 1010 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1011 m_fixhdr(m); 1012 ipstat.ips_reassembled++; 1013 IPQ_UNLOCK(); 1014 return (m); 1015 1016 dropfrag: 1017 ipstat.ips_fragdropped++; 1018 if (fp != NULL) 1019 fp->ipq_nfrags--; 1020 m_freem(m); 1021 done: 1022 IPQ_UNLOCK(); 1023 return (NULL); 1024 1025 #undef GETIP 1026 } 1027 1028 /* 1029 * Free a fragment reassembly header and all 1030 * associated datagrams. 1031 */ 1032 static void 1033 ip_freef(fhp, fp) 1034 struct ipqhead *fhp; 1035 struct ipq *fp; 1036 { 1037 register struct mbuf *q; 1038 1039 IPQ_LOCK_ASSERT(); 1040 1041 while (fp->ipq_frags) { 1042 q = fp->ipq_frags; 1043 fp->ipq_frags = q->m_nextpkt; 1044 m_freem(q); 1045 } 1046 TAILQ_REMOVE(fhp, fp, ipq_list); 1047 uma_zfree(ipq_zone, fp); 1048 nipq--; 1049 } 1050 1051 /* 1052 * IP timer processing; 1053 * if a timer expires on a reassembly 1054 * queue, discard it. 1055 */ 1056 void 1057 ip_slowtimo() 1058 { 1059 register struct ipq *fp; 1060 int i; 1061 1062 IPQ_LOCK(); 1063 for (i = 0; i < IPREASS_NHASH; i++) { 1064 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1065 struct ipq *fpp; 1066 1067 fpp = fp; 1068 fp = TAILQ_NEXT(fp, ipq_list); 1069 if(--fpp->ipq_ttl == 0) { 1070 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1071 ip_freef(&ipq[i], fpp); 1072 } 1073 } 1074 } 1075 /* 1076 * If we are over the maximum number of fragments 1077 * (due to the limit being lowered), drain off 1078 * enough to get down to the new limit. 1079 */ 1080 if (maxnipq >= 0 && nipq > maxnipq) { 1081 for (i = 0; i < IPREASS_NHASH; i++) { 1082 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1083 ipstat.ips_fragdropped += 1084 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1085 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1086 } 1087 } 1088 } 1089 IPQ_UNLOCK(); 1090 } 1091 1092 /* 1093 * Drain off all datagram fragments. 1094 */ 1095 void 1096 ip_drain() 1097 { 1098 int i; 1099 1100 IPQ_LOCK(); 1101 for (i = 0; i < IPREASS_NHASH; i++) { 1102 while(!TAILQ_EMPTY(&ipq[i])) { 1103 ipstat.ips_fragdropped += 1104 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1105 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1106 } 1107 } 1108 IPQ_UNLOCK(); 1109 in_rtqdrain(); 1110 } 1111 1112 /* 1113 * The protocol to be inserted into ip_protox[] must be already registered 1114 * in inetsw[], either statically or through pf_proto_register(). 1115 */ 1116 int 1117 ipproto_register(u_char ipproto) 1118 { 1119 struct protosw *pr; 1120 1121 /* Sanity checks. */ 1122 if (ipproto == 0) 1123 return (EPROTONOSUPPORT); 1124 1125 /* 1126 * The protocol slot must not be occupied by another protocol 1127 * already. An index pointing to IPPROTO_RAW is unused. 1128 */ 1129 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1130 if (pr == NULL) 1131 return (EPFNOSUPPORT); 1132 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1133 return (EEXIST); 1134 1135 /* Find the protocol position in inetsw[] and set the index. */ 1136 for (pr = inetdomain.dom_protosw; 1137 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1138 if (pr->pr_domain->dom_family == PF_INET && 1139 pr->pr_protocol && pr->pr_protocol == ipproto) { 1140 /* Be careful to only index valid IP protocols. */ 1141 if (pr->pr_protocol < IPPROTO_MAX) { 1142 ip_protox[pr->pr_protocol] = pr - inetsw; 1143 return (0); 1144 } else 1145 return (EINVAL); 1146 } 1147 } 1148 return (EPROTONOSUPPORT); 1149 } 1150 1151 int 1152 ipproto_unregister(u_char ipproto) 1153 { 1154 struct protosw *pr; 1155 1156 /* Sanity checks. */ 1157 if (ipproto == 0) 1158 return (EPROTONOSUPPORT); 1159 1160 /* Check if the protocol was indeed registered. */ 1161 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1162 if (pr == NULL) 1163 return (EPFNOSUPPORT); 1164 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1165 return (ENOENT); 1166 1167 /* Reset the protocol slot to IPPROTO_RAW. */ 1168 ip_protox[ipproto] = pr - inetsw; 1169 return (0); 1170 } 1171 1172 /* 1173 * Given address of next destination (final or next hop), 1174 * return internet address info of interface to be used to get there. 1175 */ 1176 struct in_ifaddr * 1177 ip_rtaddr(dst) 1178 struct in_addr dst; 1179 { 1180 struct route sro; 1181 struct sockaddr_in *sin; 1182 struct in_ifaddr *ifa; 1183 1184 bzero(&sro, sizeof(sro)); 1185 sin = (struct sockaddr_in *)&sro.ro_dst; 1186 sin->sin_family = AF_INET; 1187 sin->sin_len = sizeof(*sin); 1188 sin->sin_addr = dst; 1189 rtalloc_ign(&sro, RTF_CLONING); 1190 1191 if (sro.ro_rt == NULL) 1192 return (NULL); 1193 1194 ifa = ifatoia(sro.ro_rt->rt_ifa); 1195 RTFREE(sro.ro_rt); 1196 return (ifa); 1197 } 1198 1199 u_char inetctlerrmap[PRC_NCMDS] = { 1200 0, 0, 0, 0, 1201 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1202 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1203 EMSGSIZE, EHOSTUNREACH, 0, 0, 1204 0, 0, EHOSTUNREACH, 0, 1205 ENOPROTOOPT, ECONNREFUSED 1206 }; 1207 1208 /* 1209 * Forward a packet. If some error occurs return the sender 1210 * an icmp packet. Note we can't always generate a meaningful 1211 * icmp message because icmp doesn't have a large enough repertoire 1212 * of codes and types. 1213 * 1214 * If not forwarding, just drop the packet. This could be confusing 1215 * if ipforwarding was zero but some routing protocol was advancing 1216 * us as a gateway to somewhere. However, we must let the routing 1217 * protocol deal with that. 1218 * 1219 * The srcrt parameter indicates whether the packet is being forwarded 1220 * via a source route. 1221 */ 1222 void 1223 ip_forward(struct mbuf *m, int srcrt) 1224 { 1225 struct ip *ip = mtod(m, struct ip *); 1226 struct in_ifaddr *ia = NULL; 1227 struct mbuf *mcopy; 1228 struct in_addr dest; 1229 int error, type = 0, code = 0, mtu = 0; 1230 1231 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1232 ipstat.ips_cantforward++; 1233 m_freem(m); 1234 return; 1235 } 1236 #ifdef IPSTEALTH 1237 if (!ipstealth) { 1238 #endif 1239 if (ip->ip_ttl <= IPTTLDEC) { 1240 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1241 0, 0); 1242 return; 1243 } 1244 #ifdef IPSTEALTH 1245 } 1246 #endif 1247 1248 if (!srcrt && (ia = ip_rtaddr(ip->ip_dst)) == NULL) { 1249 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1250 return; 1251 } 1252 1253 /* 1254 * Save the IP header and at most 8 bytes of the payload, 1255 * in case we need to generate an ICMP message to the src. 1256 * 1257 * XXX this can be optimized a lot by saving the data in a local 1258 * buffer on the stack (72 bytes at most), and only allocating the 1259 * mbuf if really necessary. The vast majority of the packets 1260 * are forwarded without having to send an ICMP back (either 1261 * because unnecessary, or because rate limited), so we are 1262 * really we are wasting a lot of work here. 1263 * 1264 * We don't use m_copy() because it might return a reference 1265 * to a shared cluster. Both this function and ip_output() 1266 * assume exclusive access to the IP header in `m', so any 1267 * data in a cluster may change before we reach icmp_error(). 1268 */ 1269 MGETHDR(mcopy, M_DONTWAIT, m->m_type); 1270 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1271 /* 1272 * It's probably ok if the pkthdr dup fails (because 1273 * the deep copy of the tag chain failed), but for now 1274 * be conservative and just discard the copy since 1275 * code below may some day want the tags. 1276 */ 1277 m_free(mcopy); 1278 mcopy = NULL; 1279 } 1280 if (mcopy != NULL) { 1281 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy)); 1282 mcopy->m_pkthdr.len = mcopy->m_len; 1283 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1284 } 1285 1286 #ifdef IPSTEALTH 1287 if (!ipstealth) { 1288 #endif 1289 ip->ip_ttl -= IPTTLDEC; 1290 #ifdef IPSTEALTH 1291 } 1292 #endif 1293 1294 /* 1295 * If forwarding packet using same interface that it came in on, 1296 * perhaps should send a redirect to sender to shortcut a hop. 1297 * Only send redirect if source is sending directly to us, 1298 * and if packet was not source routed (or has any options). 1299 * Also, don't send redirect if forwarding using a default route 1300 * or a route modified by a redirect. 1301 */ 1302 dest.s_addr = 0; 1303 if (!srcrt && ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1304 struct sockaddr_in *sin; 1305 struct route ro; 1306 struct rtentry *rt; 1307 1308 bzero(&ro, sizeof(ro)); 1309 sin = (struct sockaddr_in *)&ro.ro_dst; 1310 sin->sin_family = AF_INET; 1311 sin->sin_len = sizeof(*sin); 1312 sin->sin_addr = ip->ip_dst; 1313 rtalloc_ign(&ro, RTF_CLONING); 1314 1315 rt = ro.ro_rt; 1316 1317 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1318 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1319 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1320 u_long src = ntohl(ip->ip_src.s_addr); 1321 1322 if (RTA(rt) && 1323 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1324 if (rt->rt_flags & RTF_GATEWAY) 1325 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1326 else 1327 dest.s_addr = ip->ip_dst.s_addr; 1328 /* Router requirements says to only send host redirects */ 1329 type = ICMP_REDIRECT; 1330 code = ICMP_REDIRECT_HOST; 1331 } 1332 } 1333 if (rt) 1334 RTFREE(rt); 1335 } 1336 1337 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 1338 if (error) 1339 ipstat.ips_cantforward++; 1340 else { 1341 ipstat.ips_forward++; 1342 if (type) 1343 ipstat.ips_redirectsent++; 1344 else { 1345 if (mcopy) 1346 m_freem(mcopy); 1347 return; 1348 } 1349 } 1350 if (mcopy == NULL) 1351 return; 1352 1353 switch (error) { 1354 1355 case 0: /* forwarded, but need redirect */ 1356 /* type, code set above */ 1357 break; 1358 1359 case ENETUNREACH: /* shouldn't happen, checked above */ 1360 case EHOSTUNREACH: 1361 case ENETDOWN: 1362 case EHOSTDOWN: 1363 default: 1364 type = ICMP_UNREACH; 1365 code = ICMP_UNREACH_HOST; 1366 break; 1367 1368 case EMSGSIZE: 1369 type = ICMP_UNREACH; 1370 code = ICMP_UNREACH_NEEDFRAG; 1371 1372 #if defined(IPSEC) || defined(FAST_IPSEC) 1373 mtu = ip_ipsec_mtu(m); 1374 #endif /* IPSEC */ 1375 /* 1376 * If the MTU wasn't set before use the interface mtu or 1377 * fall back to the next smaller mtu step compared to the 1378 * current packet size. 1379 */ 1380 if (mtu == 0) { 1381 if (ia != NULL) 1382 mtu = ia->ia_ifp->if_mtu; 1383 else 1384 mtu = ip_next_mtu(ip->ip_len, 0); 1385 } 1386 ipstat.ips_cantfrag++; 1387 break; 1388 1389 case ENOBUFS: 1390 /* 1391 * A router should not generate ICMP_SOURCEQUENCH as 1392 * required in RFC1812 Requirements for IP Version 4 Routers. 1393 * Source quench could be a big problem under DoS attacks, 1394 * or if the underlying interface is rate-limited. 1395 * Those who need source quench packets may re-enable them 1396 * via the net.inet.ip.sendsourcequench sysctl. 1397 */ 1398 if (ip_sendsourcequench == 0) { 1399 m_freem(mcopy); 1400 return; 1401 } else { 1402 type = ICMP_SOURCEQUENCH; 1403 code = 0; 1404 } 1405 break; 1406 1407 case EACCES: /* ipfw denied packet */ 1408 m_freem(mcopy); 1409 return; 1410 } 1411 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1412 } 1413 1414 void 1415 ip_savecontrol(inp, mp, ip, m) 1416 register struct inpcb *inp; 1417 register struct mbuf **mp; 1418 register struct ip *ip; 1419 register struct mbuf *m; 1420 { 1421 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1422 struct bintime bt; 1423 1424 bintime(&bt); 1425 if (inp->inp_socket->so_options & SO_BINTIME) { 1426 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 1427 SCM_BINTIME, SOL_SOCKET); 1428 if (*mp) 1429 mp = &(*mp)->m_next; 1430 } 1431 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1432 struct timeval tv; 1433 1434 bintime2timeval(&bt, &tv); 1435 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1436 SCM_TIMESTAMP, SOL_SOCKET); 1437 if (*mp) 1438 mp = &(*mp)->m_next; 1439 } 1440 } 1441 if (inp->inp_flags & INP_RECVDSTADDR) { 1442 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1443 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1444 if (*mp) 1445 mp = &(*mp)->m_next; 1446 } 1447 if (inp->inp_flags & INP_RECVTTL) { 1448 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1449 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1450 if (*mp) 1451 mp = &(*mp)->m_next; 1452 } 1453 #ifdef notyet 1454 /* XXX 1455 * Moving these out of udp_input() made them even more broken 1456 * than they already were. 1457 */ 1458 /* options were tossed already */ 1459 if (inp->inp_flags & INP_RECVOPTS) { 1460 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1461 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1462 if (*mp) 1463 mp = &(*mp)->m_next; 1464 } 1465 /* ip_srcroute doesn't do what we want here, need to fix */ 1466 if (inp->inp_flags & INP_RECVRETOPTS) { 1467 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1468 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1469 if (*mp) 1470 mp = &(*mp)->m_next; 1471 } 1472 #endif 1473 if (inp->inp_flags & INP_RECVIF) { 1474 struct ifnet *ifp; 1475 struct sdlbuf { 1476 struct sockaddr_dl sdl; 1477 u_char pad[32]; 1478 } sdlbuf; 1479 struct sockaddr_dl *sdp; 1480 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1481 1482 if (((ifp = m->m_pkthdr.rcvif)) 1483 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1484 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1485 /* 1486 * Change our mind and don't try copy. 1487 */ 1488 if ((sdp->sdl_family != AF_LINK) 1489 || (sdp->sdl_len > sizeof(sdlbuf))) { 1490 goto makedummy; 1491 } 1492 bcopy(sdp, sdl2, sdp->sdl_len); 1493 } else { 1494 makedummy: 1495 sdl2->sdl_len 1496 = offsetof(struct sockaddr_dl, sdl_data[0]); 1497 sdl2->sdl_family = AF_LINK; 1498 sdl2->sdl_index = 0; 1499 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1500 } 1501 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1502 IP_RECVIF, IPPROTO_IP); 1503 if (*mp) 1504 mp = &(*mp)->m_next; 1505 } 1506 } 1507 1508 /* 1509 * XXX these routines are called from the upper part of the kernel. 1510 * They need to be locked when we remove Giant. 1511 * 1512 * They could also be moved to ip_mroute.c, since all the RSVP 1513 * handling is done there already. 1514 */ 1515 static int ip_rsvp_on; 1516 struct socket *ip_rsvpd; 1517 int 1518 ip_rsvp_init(struct socket *so) 1519 { 1520 if (so->so_type != SOCK_RAW || 1521 so->so_proto->pr_protocol != IPPROTO_RSVP) 1522 return EOPNOTSUPP; 1523 1524 if (ip_rsvpd != NULL) 1525 return EADDRINUSE; 1526 1527 ip_rsvpd = so; 1528 /* 1529 * This may seem silly, but we need to be sure we don't over-increment 1530 * the RSVP counter, in case something slips up. 1531 */ 1532 if (!ip_rsvp_on) { 1533 ip_rsvp_on = 1; 1534 rsvp_on++; 1535 } 1536 1537 return 0; 1538 } 1539 1540 int 1541 ip_rsvp_done(void) 1542 { 1543 ip_rsvpd = NULL; 1544 /* 1545 * This may seem silly, but we need to be sure we don't over-decrement 1546 * the RSVP counter, in case something slips up. 1547 */ 1548 if (ip_rsvp_on) { 1549 ip_rsvp_on = 0; 1550 rsvp_on--; 1551 } 1552 return 0; 1553 } 1554 1555 void 1556 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1557 { 1558 if (rsvp_input_p) { /* call the real one if loaded */ 1559 rsvp_input_p(m, off); 1560 return; 1561 } 1562 1563 /* Can still get packets with rsvp_on = 0 if there is a local member 1564 * of the group to which the RSVP packet is addressed. But in this 1565 * case we want to throw the packet away. 1566 */ 1567 1568 if (!rsvp_on) { 1569 m_freem(m); 1570 return; 1571 } 1572 1573 if (ip_rsvpd != NULL) { 1574 rip_input(m, off); 1575 return; 1576 } 1577 /* Drop the packet */ 1578 m_freem(m); 1579 } 1580