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 static void ipq_zone_change(void *); 171 172 static int maxnipq; /* Administrative limit on # reass queues. */ 173 static int nipq = 0; /* Total # of reass queues */ 174 SYSCTL_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, &nipq, 0, 175 "Current number of IPv4 fragment reassembly queue entries"); 176 177 static int maxfragsperpacket; 178 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 179 &maxfragsperpacket, 0, 180 "Maximum number of IPv4 fragments allowed per packet"); 181 182 struct callout ipport_tick_callout; 183 184 #ifdef IPCTL_DEFMTU 185 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 186 &ip_mtu, 0, "Default MTU"); 187 #endif 188 189 #ifdef IPSTEALTH 190 int ipstealth = 0; 191 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 192 &ipstealth, 0, ""); 193 #endif 194 195 /* 196 * ipfw_ether and ipfw_bridge hooks. 197 * XXX: Temporary until those are converted to pfil_hooks as well. 198 */ 199 ip_fw_chk_t *ip_fw_chk_ptr = NULL; 200 ip_dn_io_t *ip_dn_io_ptr = NULL; 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 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, 260 NULL, EVENTHANDLER_PRI_ANY); 261 262 /* Initialize various other remaining things. */ 263 ip_id = time_second & 0xffff; 264 ipintrq.ifq_maxlen = ipqmaxlen; 265 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 266 netisr_register(NETISR_IP, ip_input, &ipintrq, NETISR_MPSAFE); 267 } 268 269 void ip_fini(xtp) 270 void *xtp; 271 { 272 callout_stop(&ipport_tick_callout); 273 } 274 275 /* 276 * Ip input routine. Checksum and byte swap header. If fragmented 277 * try to reassemble. Process options. Pass to next level. 278 */ 279 void 280 ip_input(struct mbuf *m) 281 { 282 struct ip *ip = NULL; 283 struct in_ifaddr *ia = NULL; 284 struct ifaddr *ifa; 285 int checkif, hlen = 0; 286 u_short sum; 287 int dchg = 0; /* dest changed after fw */ 288 struct in_addr odst; /* original dst address */ 289 290 M_ASSERTPKTHDR(m); 291 292 if (m->m_flags & M_FASTFWD_OURS) { 293 /* 294 * Firewall or NAT changed destination to local. 295 * We expect ip_len and ip_off to be in host byte order. 296 */ 297 m->m_flags &= ~M_FASTFWD_OURS; 298 /* Set up some basics that will be used later. */ 299 ip = mtod(m, struct ip *); 300 hlen = ip->ip_hl << 2; 301 goto ours; 302 } 303 304 ipstat.ips_total++; 305 306 if (m->m_pkthdr.len < sizeof(struct ip)) 307 goto tooshort; 308 309 if (m->m_len < sizeof (struct ip) && 310 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 311 ipstat.ips_toosmall++; 312 return; 313 } 314 ip = mtod(m, struct ip *); 315 316 if (ip->ip_v != IPVERSION) { 317 ipstat.ips_badvers++; 318 goto bad; 319 } 320 321 hlen = ip->ip_hl << 2; 322 if (hlen < sizeof(struct ip)) { /* minimum header length */ 323 ipstat.ips_badhlen++; 324 goto bad; 325 } 326 if (hlen > m->m_len) { 327 if ((m = m_pullup(m, hlen)) == NULL) { 328 ipstat.ips_badhlen++; 329 return; 330 } 331 ip = mtod(m, struct ip *); 332 } 333 334 /* 127/8 must not appear on wire - RFC1122 */ 335 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 336 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 337 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 338 ipstat.ips_badaddr++; 339 goto bad; 340 } 341 } 342 343 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 344 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 345 } else { 346 if (hlen == sizeof(struct ip)) { 347 sum = in_cksum_hdr(ip); 348 } else { 349 sum = in_cksum(m, hlen); 350 } 351 } 352 if (sum) { 353 ipstat.ips_badsum++; 354 goto bad; 355 } 356 357 #ifdef ALTQ 358 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 359 /* packet is dropped by traffic conditioner */ 360 return; 361 #endif 362 363 /* 364 * Convert fields to host representation. 365 */ 366 ip->ip_len = ntohs(ip->ip_len); 367 if (ip->ip_len < hlen) { 368 ipstat.ips_badlen++; 369 goto bad; 370 } 371 ip->ip_off = ntohs(ip->ip_off); 372 373 /* 374 * Check that the amount of data in the buffers 375 * is as at least much as the IP header would have us expect. 376 * Trim mbufs if longer than we expect. 377 * Drop packet if shorter than we expect. 378 */ 379 if (m->m_pkthdr.len < ip->ip_len) { 380 tooshort: 381 ipstat.ips_tooshort++; 382 goto bad; 383 } 384 if (m->m_pkthdr.len > ip->ip_len) { 385 if (m->m_len == m->m_pkthdr.len) { 386 m->m_len = ip->ip_len; 387 m->m_pkthdr.len = ip->ip_len; 388 } else 389 m_adj(m, ip->ip_len - m->m_pkthdr.len); 390 } 391 #if defined(IPSEC) || defined(FAST_IPSEC) 392 /* 393 * Bypass packet filtering for packets from a tunnel (gif). 394 */ 395 if (ip_ipsec_filtergif(m)) 396 goto passin; 397 #endif /* IPSEC */ 398 399 /* 400 * Run through list of hooks for input packets. 401 * 402 * NB: Beware of the destination address changing (e.g. 403 * by NAT rewriting). When this happens, tell 404 * ip_forward to do the right thing. 405 */ 406 407 /* Jump over all PFIL processing if hooks are not active. */ 408 if (!PFIL_HOOKED(&inet_pfil_hook)) 409 goto passin; 410 411 odst = ip->ip_dst; 412 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 413 PFIL_IN, NULL) != 0) 414 return; 415 if (m == NULL) /* consumed by filter */ 416 return; 417 418 ip = mtod(m, struct ip *); 419 dchg = (odst.s_addr != ip->ip_dst.s_addr); 420 421 #ifdef IPFIREWALL_FORWARD 422 if (m->m_flags & M_FASTFWD_OURS) { 423 m->m_flags &= ~M_FASTFWD_OURS; 424 goto ours; 425 } 426 #ifndef IPFIREWALL_FORWARD_EXTENDED 427 dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL); 428 #else 429 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 430 /* 431 * Directly ship on the packet. This allows to forward packets 432 * that were destined for us to some other directly connected 433 * host. 434 */ 435 ip_forward(m, dchg); 436 return; 437 } 438 #endif /* IPFIREWALL_FORWARD_EXTENDED */ 439 #endif /* IPFIREWALL_FORWARD */ 440 441 passin: 442 /* 443 * Process options and, if not destined for us, 444 * ship it on. ip_dooptions returns 1 when an 445 * error was detected (causing an icmp message 446 * to be sent and the original packet to be freed). 447 */ 448 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 449 return; 450 451 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 452 * matter if it is destined to another node, or whether it is 453 * a multicast one, RSVP wants it! and prevents it from being forwarded 454 * anywhere else. Also checks if the rsvp daemon is running before 455 * grabbing the packet. 456 */ 457 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 458 goto ours; 459 460 /* 461 * Check our list of addresses, to see if the packet is for us. 462 * If we don't have any addresses, assume any unicast packet 463 * we receive might be for us (and let the upper layers deal 464 * with it). 465 */ 466 if (TAILQ_EMPTY(&in_ifaddrhead) && 467 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 468 goto ours; 469 470 /* 471 * Enable a consistency check between the destination address 472 * and the arrival interface for a unicast packet (the RFC 1122 473 * strong ES model) if IP forwarding is disabled and the packet 474 * is not locally generated and the packet is not subject to 475 * 'ipfw fwd'. 476 * 477 * XXX - Checking also should be disabled if the destination 478 * address is ipnat'ed to a different interface. 479 * 480 * XXX - Checking is incompatible with IP aliases added 481 * to the loopback interface instead of the interface where 482 * the packets are received. 483 * 484 * XXX - This is the case for carp vhost IPs as well so we 485 * insert a workaround. If the packet got here, we already 486 * checked with carp_iamatch() and carp_forus(). 487 */ 488 checkif = ip_checkinterface && (ipforwarding == 0) && 489 m->m_pkthdr.rcvif != NULL && 490 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 491 #ifdef DEV_CARP 492 !m->m_pkthdr.rcvif->if_carp && 493 #endif 494 (dchg == 0); 495 496 /* 497 * Check for exact addresses in the hash bucket. 498 */ 499 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 500 /* 501 * If the address matches, verify that the packet 502 * arrived via the correct interface if checking is 503 * enabled. 504 */ 505 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 506 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 507 goto ours; 508 } 509 /* 510 * Check for broadcast addresses. 511 * 512 * Only accept broadcast packets that arrive via the matching 513 * interface. Reception of forwarded directed broadcasts would 514 * be handled via ip_forward() and ether_output() with the loopback 515 * into the stack for SIMPLEX interfaces handled by ether_output(). 516 */ 517 if (m->m_pkthdr.rcvif != NULL && 518 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 519 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 520 if (ifa->ifa_addr->sa_family != AF_INET) 521 continue; 522 ia = ifatoia(ifa); 523 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 524 ip->ip_dst.s_addr) 525 goto ours; 526 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 527 goto ours; 528 #ifdef BOOTP_COMPAT 529 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 530 goto ours; 531 #endif 532 } 533 } 534 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 535 struct in_multi *inm; 536 if (ip_mrouter) { 537 /* 538 * If we are acting as a multicast router, all 539 * incoming multicast packets are passed to the 540 * kernel-level multicast forwarding function. 541 * The packet is returned (relatively) intact; if 542 * ip_mforward() returns a non-zero value, the packet 543 * must be discarded, else it may be accepted below. 544 */ 545 if (ip_mforward && 546 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 547 ipstat.ips_cantforward++; 548 m_freem(m); 549 return; 550 } 551 552 /* 553 * The process-level routing daemon needs to receive 554 * all multicast IGMP packets, whether or not this 555 * host belongs to their destination groups. 556 */ 557 if (ip->ip_p == IPPROTO_IGMP) 558 goto ours; 559 ipstat.ips_forward++; 560 } 561 /* 562 * See if we belong to the destination multicast group on the 563 * arrival interface. 564 */ 565 IN_MULTI_LOCK(); 566 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 567 IN_MULTI_UNLOCK(); 568 if (inm == NULL) { 569 ipstat.ips_notmember++; 570 m_freem(m); 571 return; 572 } 573 goto ours; 574 } 575 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 576 goto ours; 577 if (ip->ip_dst.s_addr == INADDR_ANY) 578 goto ours; 579 580 /* 581 * FAITH(Firewall Aided Internet Translator) 582 */ 583 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 584 if (ip_keepfaith) { 585 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 586 goto ours; 587 } 588 m_freem(m); 589 return; 590 } 591 592 /* 593 * Not for us; forward if possible and desirable. 594 */ 595 if (ipforwarding == 0) { 596 ipstat.ips_cantforward++; 597 m_freem(m); 598 } else { 599 #if defined(IPSEC) || defined(FAST_IPSEC) 600 if (ip_ipsec_fwd(m)) 601 goto bad; 602 #endif /* IPSEC */ 603 ip_forward(m, dchg); 604 } 605 return; 606 607 ours: 608 #ifdef IPSTEALTH 609 /* 610 * IPSTEALTH: Process non-routing options only 611 * if the packet is destined for us. 612 */ 613 if (ipstealth && hlen > sizeof (struct ip) && 614 ip_dooptions(m, 1)) 615 return; 616 #endif /* IPSTEALTH */ 617 618 /* Count the packet in the ip address stats */ 619 if (ia != NULL) { 620 ia->ia_ifa.if_ipackets++; 621 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 622 } 623 624 /* 625 * Attempt reassembly; if it succeeds, proceed. 626 * ip_reass() will return a different mbuf. 627 */ 628 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 629 m = ip_reass(m); 630 if (m == NULL) 631 return; 632 ip = mtod(m, struct ip *); 633 /* Get the header length of the reassembled packet */ 634 hlen = ip->ip_hl << 2; 635 } 636 637 /* 638 * Further protocols expect the packet length to be w/o the 639 * IP header. 640 */ 641 ip->ip_len -= hlen; 642 643 #if defined(IPSEC) || defined(FAST_IPSEC) 644 /* 645 * enforce IPsec policy checking if we are seeing last header. 646 * note that we do not visit this with protocols with pcb layer 647 * code - like udp/tcp/raw ip. 648 */ 649 if (ip_ipsec_input(m)) 650 goto bad; 651 #endif /* IPSEC */ 652 653 /* 654 * Switch out to protocol's input routine. 655 */ 656 ipstat.ips_delivered++; 657 658 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 659 return; 660 bad: 661 m_freem(m); 662 } 663 664 /* 665 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 666 * max has slightly different semantics than the sysctl, for historical 667 * reasons. 668 */ 669 static void 670 maxnipq_update(void) 671 { 672 673 /* 674 * -1 for unlimited allocation. 675 */ 676 if (maxnipq < 0) 677 uma_zone_set_max(ipq_zone, 0); 678 /* 679 * Positive number for specific bound. 680 */ 681 if (maxnipq > 0) 682 uma_zone_set_max(ipq_zone, maxnipq); 683 /* 684 * Zero specifies no further fragment queue allocation -- set the 685 * bound very low, but rely on implementation elsewhere to actually 686 * prevent allocation and reclaim current queues. 687 */ 688 if (maxnipq == 0) 689 uma_zone_set_max(ipq_zone, 1); 690 } 691 692 static void 693 ipq_zone_change(void *tag) 694 { 695 696 if (maxnipq > 0 && maxnipq < (nmbclusters / 32)) { 697 maxnipq = nmbclusters / 32; 698 maxnipq_update(); 699 } 700 } 701 702 static int 703 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 704 { 705 int error, i; 706 707 i = maxnipq; 708 error = sysctl_handle_int(oidp, &i, 0, req); 709 if (error || !req->newptr) 710 return (error); 711 712 /* 713 * XXXRW: Might be a good idea to sanity check the argument and place 714 * an extreme upper bound. 715 */ 716 if (i < -1) 717 return (EINVAL); 718 maxnipq = i; 719 maxnipq_update(); 720 return (0); 721 } 722 723 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 724 NULL, 0, sysctl_maxnipq, "I", 725 "Maximum number of IPv4 fragment reassembly queue entries"); 726 727 /* 728 * Take incoming datagram fragment and try to reassemble it into 729 * whole datagram. If the argument is the first fragment or one 730 * in between the function will return NULL and store the mbuf 731 * in the fragment chain. If the argument is the last fragment 732 * the packet will be reassembled and the pointer to the new 733 * mbuf returned for further processing. Only m_tags attached 734 * to the first packet/fragment are preserved. 735 * The IP header is *NOT* adjusted out of iplen. 736 */ 737 738 struct mbuf * 739 ip_reass(struct mbuf *m) 740 { 741 struct ip *ip; 742 struct mbuf *p, *q, *nq, *t; 743 struct ipq *fp = NULL; 744 struct ipqhead *head; 745 int i, hlen, next; 746 u_int8_t ecn, ecn0; 747 u_short hash; 748 749 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 750 if (maxnipq == 0 || maxfragsperpacket == 0) { 751 ipstat.ips_fragments++; 752 ipstat.ips_fragdropped++; 753 m_freem(m); 754 return (NULL); 755 } 756 757 ip = mtod(m, struct ip *); 758 hlen = ip->ip_hl << 2; 759 760 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 761 head = &ipq[hash]; 762 IPQ_LOCK(); 763 764 /* 765 * Look for queue of fragments 766 * of this datagram. 767 */ 768 TAILQ_FOREACH(fp, head, ipq_list) 769 if (ip->ip_id == fp->ipq_id && 770 ip->ip_src.s_addr == fp->ipq_src.s_addr && 771 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 772 #ifdef MAC 773 mac_fragment_match(m, fp) && 774 #endif 775 ip->ip_p == fp->ipq_p) 776 goto found; 777 778 fp = NULL; 779 780 /* 781 * Attempt to trim the number of allocated fragment queues if it 782 * exceeds the administrative limit. 783 */ 784 if ((nipq > maxnipq) && (maxnipq > 0)) { 785 /* 786 * drop something from the tail of the current queue 787 * before proceeding further 788 */ 789 struct ipq *q = TAILQ_LAST(head, ipqhead); 790 if (q == NULL) { /* gak */ 791 for (i = 0; i < IPREASS_NHASH; i++) { 792 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 793 if (r) { 794 ipstat.ips_fragtimeout += r->ipq_nfrags; 795 ip_freef(&ipq[i], r); 796 break; 797 } 798 } 799 } else { 800 ipstat.ips_fragtimeout += q->ipq_nfrags; 801 ip_freef(head, q); 802 } 803 } 804 805 found: 806 /* 807 * Adjust ip_len to not reflect header, 808 * convert offset of this to bytes. 809 */ 810 ip->ip_len -= hlen; 811 if (ip->ip_off & IP_MF) { 812 /* 813 * Make sure that fragments have a data length 814 * that's a non-zero multiple of 8 bytes. 815 */ 816 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 817 ipstat.ips_toosmall++; /* XXX */ 818 goto dropfrag; 819 } 820 m->m_flags |= M_FRAG; 821 } else 822 m->m_flags &= ~M_FRAG; 823 ip->ip_off <<= 3; 824 825 826 /* 827 * Attempt reassembly; if it succeeds, proceed. 828 * ip_reass() will return a different mbuf. 829 */ 830 ipstat.ips_fragments++; 831 m->m_pkthdr.header = ip; 832 833 /* Previous ip_reass() started here. */ 834 /* 835 * Presence of header sizes in mbufs 836 * would confuse code below. 837 */ 838 m->m_data += hlen; 839 m->m_len -= hlen; 840 841 /* 842 * If first fragment to arrive, create a reassembly queue. 843 */ 844 if (fp == NULL) { 845 fp = uma_zalloc(ipq_zone, M_NOWAIT); 846 if (fp == NULL) 847 goto dropfrag; 848 #ifdef MAC 849 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 850 uma_zfree(ipq_zone, fp); 851 fp = NULL; 852 goto dropfrag; 853 } 854 mac_create_ipq(m, fp); 855 #endif 856 TAILQ_INSERT_HEAD(head, fp, ipq_list); 857 nipq++; 858 fp->ipq_nfrags = 1; 859 fp->ipq_ttl = IPFRAGTTL; 860 fp->ipq_p = ip->ip_p; 861 fp->ipq_id = ip->ip_id; 862 fp->ipq_src = ip->ip_src; 863 fp->ipq_dst = ip->ip_dst; 864 fp->ipq_frags = m; 865 m->m_nextpkt = NULL; 866 goto done; 867 } else { 868 fp->ipq_nfrags++; 869 #ifdef MAC 870 mac_update_ipq(m, fp); 871 #endif 872 } 873 874 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 875 876 /* 877 * Handle ECN by comparing this segment with the first one; 878 * if CE is set, do not lose CE. 879 * drop if CE and not-ECT are mixed for the same packet. 880 */ 881 ecn = ip->ip_tos & IPTOS_ECN_MASK; 882 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 883 if (ecn == IPTOS_ECN_CE) { 884 if (ecn0 == IPTOS_ECN_NOTECT) 885 goto dropfrag; 886 if (ecn0 != IPTOS_ECN_CE) 887 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 888 } 889 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 890 goto dropfrag; 891 892 /* 893 * Find a segment which begins after this one does. 894 */ 895 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 896 if (GETIP(q)->ip_off > ip->ip_off) 897 break; 898 899 /* 900 * If there is a preceding segment, it may provide some of 901 * our data already. If so, drop the data from the incoming 902 * segment. If it provides all of our data, drop us, otherwise 903 * stick new segment in the proper place. 904 * 905 * If some of the data is dropped from the the preceding 906 * segment, then it's checksum is invalidated. 907 */ 908 if (p) { 909 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 910 if (i > 0) { 911 if (i >= ip->ip_len) 912 goto dropfrag; 913 m_adj(m, i); 914 m->m_pkthdr.csum_flags = 0; 915 ip->ip_off += i; 916 ip->ip_len -= i; 917 } 918 m->m_nextpkt = p->m_nextpkt; 919 p->m_nextpkt = m; 920 } else { 921 m->m_nextpkt = fp->ipq_frags; 922 fp->ipq_frags = m; 923 } 924 925 /* 926 * While we overlap succeeding segments trim them or, 927 * if they are completely covered, dequeue them. 928 */ 929 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 930 q = nq) { 931 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 932 if (i < GETIP(q)->ip_len) { 933 GETIP(q)->ip_len -= i; 934 GETIP(q)->ip_off += i; 935 m_adj(q, i); 936 q->m_pkthdr.csum_flags = 0; 937 break; 938 } 939 nq = q->m_nextpkt; 940 m->m_nextpkt = nq; 941 ipstat.ips_fragdropped++; 942 fp->ipq_nfrags--; 943 m_freem(q); 944 } 945 946 /* 947 * Check for complete reassembly and perform frag per packet 948 * limiting. 949 * 950 * Frag limiting is performed here so that the nth frag has 951 * a chance to complete the packet before we drop the packet. 952 * As a result, n+1 frags are actually allowed per packet, but 953 * only n will ever be stored. (n = maxfragsperpacket.) 954 * 955 */ 956 next = 0; 957 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 958 if (GETIP(q)->ip_off != next) { 959 if (fp->ipq_nfrags > maxfragsperpacket) { 960 ipstat.ips_fragdropped += fp->ipq_nfrags; 961 ip_freef(head, fp); 962 } 963 goto done; 964 } 965 next += GETIP(q)->ip_len; 966 } 967 /* Make sure the last packet didn't have the IP_MF flag */ 968 if (p->m_flags & M_FRAG) { 969 if (fp->ipq_nfrags > maxfragsperpacket) { 970 ipstat.ips_fragdropped += fp->ipq_nfrags; 971 ip_freef(head, fp); 972 } 973 goto done; 974 } 975 976 /* 977 * Reassembly is complete. Make sure the packet is a sane size. 978 */ 979 q = fp->ipq_frags; 980 ip = GETIP(q); 981 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 982 ipstat.ips_toolong++; 983 ipstat.ips_fragdropped += fp->ipq_nfrags; 984 ip_freef(head, fp); 985 goto done; 986 } 987 988 /* 989 * Concatenate fragments. 990 */ 991 m = q; 992 t = m->m_next; 993 m->m_next = NULL; 994 m_cat(m, t); 995 nq = q->m_nextpkt; 996 q->m_nextpkt = NULL; 997 for (q = nq; q != NULL; q = nq) { 998 nq = q->m_nextpkt; 999 q->m_nextpkt = NULL; 1000 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1001 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1002 m_cat(m, q); 1003 } 1004 /* 1005 * In order to do checksumming faster we do 'end-around carry' here 1006 * (and not in for{} loop), though it implies we are not going to 1007 * reassemble more than 64k fragments. 1008 */ 1009 m->m_pkthdr.csum_data = 1010 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1011 #ifdef MAC 1012 mac_create_datagram_from_ipq(fp, m); 1013 mac_destroy_ipq(fp); 1014 #endif 1015 1016 /* 1017 * Create header for new ip packet by modifying header of first 1018 * packet; dequeue and discard fragment reassembly header. 1019 * Make header visible. 1020 */ 1021 ip->ip_len = (ip->ip_hl << 2) + next; 1022 ip->ip_src = fp->ipq_src; 1023 ip->ip_dst = fp->ipq_dst; 1024 TAILQ_REMOVE(head, fp, ipq_list); 1025 nipq--; 1026 uma_zfree(ipq_zone, fp); 1027 m->m_len += (ip->ip_hl << 2); 1028 m->m_data -= (ip->ip_hl << 2); 1029 /* some debugging cruft by sklower, below, will go away soon */ 1030 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1031 m_fixhdr(m); 1032 ipstat.ips_reassembled++; 1033 IPQ_UNLOCK(); 1034 return (m); 1035 1036 dropfrag: 1037 ipstat.ips_fragdropped++; 1038 if (fp != NULL) 1039 fp->ipq_nfrags--; 1040 m_freem(m); 1041 done: 1042 IPQ_UNLOCK(); 1043 return (NULL); 1044 1045 #undef GETIP 1046 } 1047 1048 /* 1049 * Free a fragment reassembly header and all 1050 * associated datagrams. 1051 */ 1052 static void 1053 ip_freef(fhp, fp) 1054 struct ipqhead *fhp; 1055 struct ipq *fp; 1056 { 1057 register struct mbuf *q; 1058 1059 IPQ_LOCK_ASSERT(); 1060 1061 while (fp->ipq_frags) { 1062 q = fp->ipq_frags; 1063 fp->ipq_frags = q->m_nextpkt; 1064 m_freem(q); 1065 } 1066 TAILQ_REMOVE(fhp, fp, ipq_list); 1067 uma_zfree(ipq_zone, fp); 1068 nipq--; 1069 } 1070 1071 /* 1072 * IP timer processing; 1073 * if a timer expires on a reassembly 1074 * queue, discard it. 1075 */ 1076 void 1077 ip_slowtimo() 1078 { 1079 register struct ipq *fp; 1080 int i; 1081 1082 IPQ_LOCK(); 1083 for (i = 0; i < IPREASS_NHASH; i++) { 1084 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1085 struct ipq *fpp; 1086 1087 fpp = fp; 1088 fp = TAILQ_NEXT(fp, ipq_list); 1089 if(--fpp->ipq_ttl == 0) { 1090 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1091 ip_freef(&ipq[i], fpp); 1092 } 1093 } 1094 } 1095 /* 1096 * If we are over the maximum number of fragments 1097 * (due to the limit being lowered), drain off 1098 * enough to get down to the new limit. 1099 */ 1100 if (maxnipq >= 0 && nipq > maxnipq) { 1101 for (i = 0; i < IPREASS_NHASH; i++) { 1102 while (nipq > maxnipq && !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 } 1109 IPQ_UNLOCK(); 1110 } 1111 1112 /* 1113 * Drain off all datagram fragments. 1114 */ 1115 void 1116 ip_drain() 1117 { 1118 int i; 1119 1120 IPQ_LOCK(); 1121 for (i = 0; i < IPREASS_NHASH; i++) { 1122 while(!TAILQ_EMPTY(&ipq[i])) { 1123 ipstat.ips_fragdropped += 1124 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1125 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1126 } 1127 } 1128 IPQ_UNLOCK(); 1129 in_rtqdrain(); 1130 } 1131 1132 /* 1133 * The protocol to be inserted into ip_protox[] must be already registered 1134 * in inetsw[], either statically or through pf_proto_register(). 1135 */ 1136 int 1137 ipproto_register(u_char ipproto) 1138 { 1139 struct protosw *pr; 1140 1141 /* Sanity checks. */ 1142 if (ipproto == 0) 1143 return (EPROTONOSUPPORT); 1144 1145 /* 1146 * The protocol slot must not be occupied by another protocol 1147 * already. An index pointing to IPPROTO_RAW is unused. 1148 */ 1149 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1150 if (pr == NULL) 1151 return (EPFNOSUPPORT); 1152 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1153 return (EEXIST); 1154 1155 /* Find the protocol position in inetsw[] and set the index. */ 1156 for (pr = inetdomain.dom_protosw; 1157 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1158 if (pr->pr_domain->dom_family == PF_INET && 1159 pr->pr_protocol && pr->pr_protocol == ipproto) { 1160 /* Be careful to only index valid IP protocols. */ 1161 if (pr->pr_protocol < IPPROTO_MAX) { 1162 ip_protox[pr->pr_protocol] = pr - inetsw; 1163 return (0); 1164 } else 1165 return (EINVAL); 1166 } 1167 } 1168 return (EPROTONOSUPPORT); 1169 } 1170 1171 int 1172 ipproto_unregister(u_char ipproto) 1173 { 1174 struct protosw *pr; 1175 1176 /* Sanity checks. */ 1177 if (ipproto == 0) 1178 return (EPROTONOSUPPORT); 1179 1180 /* Check if the protocol was indeed registered. */ 1181 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1182 if (pr == NULL) 1183 return (EPFNOSUPPORT); 1184 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1185 return (ENOENT); 1186 1187 /* Reset the protocol slot to IPPROTO_RAW. */ 1188 ip_protox[ipproto] = pr - inetsw; 1189 return (0); 1190 } 1191 1192 /* 1193 * Given address of next destination (final or next hop), 1194 * return internet address info of interface to be used to get there. 1195 */ 1196 struct in_ifaddr * 1197 ip_rtaddr(dst) 1198 struct in_addr dst; 1199 { 1200 struct route sro; 1201 struct sockaddr_in *sin; 1202 struct in_ifaddr *ifa; 1203 1204 bzero(&sro, sizeof(sro)); 1205 sin = (struct sockaddr_in *)&sro.ro_dst; 1206 sin->sin_family = AF_INET; 1207 sin->sin_len = sizeof(*sin); 1208 sin->sin_addr = dst; 1209 rtalloc_ign(&sro, RTF_CLONING); 1210 1211 if (sro.ro_rt == NULL) 1212 return (NULL); 1213 1214 ifa = ifatoia(sro.ro_rt->rt_ifa); 1215 RTFREE(sro.ro_rt); 1216 return (ifa); 1217 } 1218 1219 u_char inetctlerrmap[PRC_NCMDS] = { 1220 0, 0, 0, 0, 1221 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1222 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1223 EMSGSIZE, EHOSTUNREACH, 0, 0, 1224 0, 0, EHOSTUNREACH, 0, 1225 ENOPROTOOPT, ECONNREFUSED 1226 }; 1227 1228 /* 1229 * Forward a packet. If some error occurs return the sender 1230 * an icmp packet. Note we can't always generate a meaningful 1231 * icmp message because icmp doesn't have a large enough repertoire 1232 * of codes and types. 1233 * 1234 * If not forwarding, just drop the packet. This could be confusing 1235 * if ipforwarding was zero but some routing protocol was advancing 1236 * us as a gateway to somewhere. However, we must let the routing 1237 * protocol deal with that. 1238 * 1239 * The srcrt parameter indicates whether the packet is being forwarded 1240 * via a source route. 1241 */ 1242 void 1243 ip_forward(struct mbuf *m, int srcrt) 1244 { 1245 struct ip *ip = mtod(m, struct ip *); 1246 struct in_ifaddr *ia = NULL; 1247 struct mbuf *mcopy; 1248 struct in_addr dest; 1249 int error, type = 0, code = 0, mtu = 0; 1250 1251 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1252 ipstat.ips_cantforward++; 1253 m_freem(m); 1254 return; 1255 } 1256 #ifdef IPSTEALTH 1257 if (!ipstealth) { 1258 #endif 1259 if (ip->ip_ttl <= IPTTLDEC) { 1260 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1261 0, 0); 1262 return; 1263 } 1264 #ifdef IPSTEALTH 1265 } 1266 #endif 1267 1268 if (!srcrt && (ia = ip_rtaddr(ip->ip_dst)) == NULL) { 1269 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1270 return; 1271 } 1272 1273 /* 1274 * Save the IP header and at most 8 bytes of the payload, 1275 * in case we need to generate an ICMP message to the src. 1276 * 1277 * XXX this can be optimized a lot by saving the data in a local 1278 * buffer on the stack (72 bytes at most), and only allocating the 1279 * mbuf if really necessary. The vast majority of the packets 1280 * are forwarded without having to send an ICMP back (either 1281 * because unnecessary, or because rate limited), so we are 1282 * really we are wasting a lot of work here. 1283 * 1284 * We don't use m_copy() because it might return a reference 1285 * to a shared cluster. Both this function and ip_output() 1286 * assume exclusive access to the IP header in `m', so any 1287 * data in a cluster may change before we reach icmp_error(). 1288 */ 1289 MGETHDR(mcopy, M_DONTWAIT, m->m_type); 1290 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1291 /* 1292 * It's probably ok if the pkthdr dup fails (because 1293 * the deep copy of the tag chain failed), but for now 1294 * be conservative and just discard the copy since 1295 * code below may some day want the tags. 1296 */ 1297 m_free(mcopy); 1298 mcopy = NULL; 1299 } 1300 if (mcopy != NULL) { 1301 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy)); 1302 mcopy->m_pkthdr.len = mcopy->m_len; 1303 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1304 } 1305 1306 #ifdef IPSTEALTH 1307 if (!ipstealth) { 1308 #endif 1309 ip->ip_ttl -= IPTTLDEC; 1310 #ifdef IPSTEALTH 1311 } 1312 #endif 1313 1314 /* 1315 * If forwarding packet using same interface that it came in on, 1316 * perhaps should send a redirect to sender to shortcut a hop. 1317 * Only send redirect if source is sending directly to us, 1318 * and if packet was not source routed (or has any options). 1319 * Also, don't send redirect if forwarding using a default route 1320 * or a route modified by a redirect. 1321 */ 1322 dest.s_addr = 0; 1323 if (!srcrt && ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1324 struct sockaddr_in *sin; 1325 struct route ro; 1326 struct rtentry *rt; 1327 1328 bzero(&ro, sizeof(ro)); 1329 sin = (struct sockaddr_in *)&ro.ro_dst; 1330 sin->sin_family = AF_INET; 1331 sin->sin_len = sizeof(*sin); 1332 sin->sin_addr = ip->ip_dst; 1333 rtalloc_ign(&ro, RTF_CLONING); 1334 1335 rt = ro.ro_rt; 1336 1337 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1338 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1339 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1340 u_long src = ntohl(ip->ip_src.s_addr); 1341 1342 if (RTA(rt) && 1343 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1344 if (rt->rt_flags & RTF_GATEWAY) 1345 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1346 else 1347 dest.s_addr = ip->ip_dst.s_addr; 1348 /* Router requirements says to only send host redirects */ 1349 type = ICMP_REDIRECT; 1350 code = ICMP_REDIRECT_HOST; 1351 } 1352 } 1353 if (rt) 1354 RTFREE(rt); 1355 } 1356 1357 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 1358 if (error) 1359 ipstat.ips_cantforward++; 1360 else { 1361 ipstat.ips_forward++; 1362 if (type) 1363 ipstat.ips_redirectsent++; 1364 else { 1365 if (mcopy) 1366 m_freem(mcopy); 1367 return; 1368 } 1369 } 1370 if (mcopy == NULL) 1371 return; 1372 1373 switch (error) { 1374 1375 case 0: /* forwarded, but need redirect */ 1376 /* type, code set above */ 1377 break; 1378 1379 case ENETUNREACH: /* shouldn't happen, checked above */ 1380 case EHOSTUNREACH: 1381 case ENETDOWN: 1382 case EHOSTDOWN: 1383 default: 1384 type = ICMP_UNREACH; 1385 code = ICMP_UNREACH_HOST; 1386 break; 1387 1388 case EMSGSIZE: 1389 type = ICMP_UNREACH; 1390 code = ICMP_UNREACH_NEEDFRAG; 1391 1392 #if defined(IPSEC) || defined(FAST_IPSEC) 1393 mtu = ip_ipsec_mtu(m); 1394 #endif /* IPSEC */ 1395 /* 1396 * If the MTU wasn't set before use the interface mtu or 1397 * fall back to the next smaller mtu step compared to the 1398 * current packet size. 1399 */ 1400 if (mtu == 0) { 1401 if (ia != NULL) 1402 mtu = ia->ia_ifp->if_mtu; 1403 else 1404 mtu = ip_next_mtu(ip->ip_len, 0); 1405 } 1406 ipstat.ips_cantfrag++; 1407 break; 1408 1409 case ENOBUFS: 1410 /* 1411 * A router should not generate ICMP_SOURCEQUENCH as 1412 * required in RFC1812 Requirements for IP Version 4 Routers. 1413 * Source quench could be a big problem under DoS attacks, 1414 * or if the underlying interface is rate-limited. 1415 * Those who need source quench packets may re-enable them 1416 * via the net.inet.ip.sendsourcequench sysctl. 1417 */ 1418 if (ip_sendsourcequench == 0) { 1419 m_freem(mcopy); 1420 return; 1421 } else { 1422 type = ICMP_SOURCEQUENCH; 1423 code = 0; 1424 } 1425 break; 1426 1427 case EACCES: /* ipfw denied packet */ 1428 m_freem(mcopy); 1429 return; 1430 } 1431 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1432 } 1433 1434 void 1435 ip_savecontrol(inp, mp, ip, m) 1436 register struct inpcb *inp; 1437 register struct mbuf **mp; 1438 register struct ip *ip; 1439 register struct mbuf *m; 1440 { 1441 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1442 struct bintime bt; 1443 1444 bintime(&bt); 1445 if (inp->inp_socket->so_options & SO_BINTIME) { 1446 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 1447 SCM_BINTIME, SOL_SOCKET); 1448 if (*mp) 1449 mp = &(*mp)->m_next; 1450 } 1451 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1452 struct timeval tv; 1453 1454 bintime2timeval(&bt, &tv); 1455 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1456 SCM_TIMESTAMP, SOL_SOCKET); 1457 if (*mp) 1458 mp = &(*mp)->m_next; 1459 } 1460 } 1461 if (inp->inp_flags & INP_RECVDSTADDR) { 1462 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1463 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1464 if (*mp) 1465 mp = &(*mp)->m_next; 1466 } 1467 if (inp->inp_flags & INP_RECVTTL) { 1468 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1469 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1470 if (*mp) 1471 mp = &(*mp)->m_next; 1472 } 1473 #ifdef notyet 1474 /* XXX 1475 * Moving these out of udp_input() made them even more broken 1476 * than they already were. 1477 */ 1478 /* options were tossed already */ 1479 if (inp->inp_flags & INP_RECVOPTS) { 1480 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1481 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1482 if (*mp) 1483 mp = &(*mp)->m_next; 1484 } 1485 /* ip_srcroute doesn't do what we want here, need to fix */ 1486 if (inp->inp_flags & INP_RECVRETOPTS) { 1487 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1488 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1489 if (*mp) 1490 mp = &(*mp)->m_next; 1491 } 1492 #endif 1493 if (inp->inp_flags & INP_RECVIF) { 1494 struct ifnet *ifp; 1495 struct sdlbuf { 1496 struct sockaddr_dl sdl; 1497 u_char pad[32]; 1498 } sdlbuf; 1499 struct sockaddr_dl *sdp; 1500 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1501 1502 if (((ifp = m->m_pkthdr.rcvif)) 1503 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1504 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1505 /* 1506 * Change our mind and don't try copy. 1507 */ 1508 if ((sdp->sdl_family != AF_LINK) 1509 || (sdp->sdl_len > sizeof(sdlbuf))) { 1510 goto makedummy; 1511 } 1512 bcopy(sdp, sdl2, sdp->sdl_len); 1513 } else { 1514 makedummy: 1515 sdl2->sdl_len 1516 = offsetof(struct sockaddr_dl, sdl_data[0]); 1517 sdl2->sdl_family = AF_LINK; 1518 sdl2->sdl_index = 0; 1519 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1520 } 1521 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1522 IP_RECVIF, IPPROTO_IP); 1523 if (*mp) 1524 mp = &(*mp)->m_next; 1525 } 1526 } 1527 1528 /* 1529 * XXX these routines are called from the upper part of the kernel. 1530 * They need to be locked when we remove Giant. 1531 * 1532 * They could also be moved to ip_mroute.c, since all the RSVP 1533 * handling is done there already. 1534 */ 1535 static int ip_rsvp_on; 1536 struct socket *ip_rsvpd; 1537 int 1538 ip_rsvp_init(struct socket *so) 1539 { 1540 if (so->so_type != SOCK_RAW || 1541 so->so_proto->pr_protocol != IPPROTO_RSVP) 1542 return EOPNOTSUPP; 1543 1544 if (ip_rsvpd != NULL) 1545 return EADDRINUSE; 1546 1547 ip_rsvpd = so; 1548 /* 1549 * This may seem silly, but we need to be sure we don't over-increment 1550 * the RSVP counter, in case something slips up. 1551 */ 1552 if (!ip_rsvp_on) { 1553 ip_rsvp_on = 1; 1554 rsvp_on++; 1555 } 1556 1557 return 0; 1558 } 1559 1560 int 1561 ip_rsvp_done(void) 1562 { 1563 ip_rsvpd = NULL; 1564 /* 1565 * This may seem silly, but we need to be sure we don't over-decrement 1566 * the RSVP counter, in case something slips up. 1567 */ 1568 if (ip_rsvp_on) { 1569 ip_rsvp_on = 0; 1570 rsvp_on--; 1571 } 1572 return 0; 1573 } 1574 1575 void 1576 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1577 { 1578 if (rsvp_input_p) { /* call the real one if loaded */ 1579 rsvp_input_p(m, off); 1580 return; 1581 } 1582 1583 /* Can still get packets with rsvp_on = 0 if there is a local member 1584 * of the group to which the RSVP packet is addressed. But in this 1585 * case we want to throw the packet away. 1586 */ 1587 1588 if (!rsvp_on) { 1589 m_freem(m); 1590 return; 1591 } 1592 1593 if (ip_rsvpd != NULL) { 1594 rip_input(m, off); 1595 return; 1596 } 1597 /* Drop the packet */ 1598 m_freem(m); 1599 } 1600