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/mbuf.h> 44 #include <sys/malloc.h> 45 #include <sys/domain.h> 46 #include <sys/protosw.h> 47 #include <sys/socket.h> 48 #include <sys/time.h> 49 #include <sys/kernel.h> 50 #include <sys/syslog.h> 51 #include <sys/sysctl.h> 52 53 #include <net/pfil.h> 54 #include <net/if.h> 55 #include <net/if_types.h> 56 #include <net/if_var.h> 57 #include <net/if_dl.h> 58 #include <net/route.h> 59 #include <net/netisr.h> 60 61 #include <netinet/in.h> 62 #include <netinet/in_systm.h> 63 #include <netinet/in_var.h> 64 #include <netinet/ip.h> 65 #include <netinet/in_pcb.h> 66 #include <netinet/ip_var.h> 67 #include <netinet/ip_icmp.h> 68 #include <netinet/ip_options.h> 69 #include <machine/in_cksum.h> 70 #ifdef DEV_CARP 71 #include <netinet/ip_carp.h> 72 #endif 73 #if defined(IPSEC) || defined(FAST_IPSEC) 74 #include <netinet/ip_ipsec.h> 75 #endif /* IPSEC */ 76 77 #include <sys/socketvar.h> 78 79 /* XXX: Temporary until ipfw_ether and ipfw_bridge are converted. */ 80 #include <netinet/ip_fw.h> 81 #include <netinet/ip_dummynet.h> 82 83 #include <security/mac/mac_framework.h> 84 85 int rsvp_on = 0; 86 87 int ipforwarding = 0; 88 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 89 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 90 91 static int ipsendredirects = 1; /* XXX */ 92 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 93 &ipsendredirects, 0, "Enable sending IP redirects"); 94 95 int ip_defttl = IPDEFTTL; 96 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 97 &ip_defttl, 0, "Maximum TTL on IP packets"); 98 99 static int ip_keepfaith = 0; 100 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 101 &ip_keepfaith, 0, 102 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 103 104 static int ip_sendsourcequench = 0; 105 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 106 &ip_sendsourcequench, 0, 107 "Enable the transmission of source quench packets"); 108 109 int ip_do_randomid = 0; 110 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 111 &ip_do_randomid, 0, 112 "Assign random ip_id values"); 113 114 /* 115 * XXX - Setting ip_checkinterface mostly implements the receive side of 116 * the Strong ES model described in RFC 1122, but since the routing table 117 * and transmit implementation do not implement the Strong ES model, 118 * setting this to 1 results in an odd hybrid. 119 * 120 * XXX - ip_checkinterface currently must be disabled if you use ipnat 121 * to translate the destination address to another local interface. 122 * 123 * XXX - ip_checkinterface must be disabled if you add IP aliases 124 * to the loopback interface instead of the interface where the 125 * packets for those addresses are received. 126 */ 127 static int ip_checkinterface = 0; 128 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 129 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 130 131 struct pfil_head inet_pfil_hook; /* Packet filter hooks */ 132 133 static struct ifqueue ipintrq; 134 static int ipqmaxlen = IFQ_MAXLEN; 135 136 extern struct domain inetdomain; 137 extern struct protosw inetsw[]; 138 u_char ip_protox[IPPROTO_MAX]; 139 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 140 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 141 u_long in_ifaddrhmask; /* mask for hash table */ 142 143 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 144 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 145 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 146 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 147 148 struct ipstat ipstat; 149 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 150 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 151 152 /* 153 * IP datagram reassembly. 154 */ 155 #define IPREASS_NHASH_LOG2 6 156 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 157 #define IPREASS_HMASK (IPREASS_NHASH - 1) 158 #define IPREASS_HASH(x,y) \ 159 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 160 161 static uma_zone_t ipq_zone; 162 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 163 static struct mtx ipqlock; 164 165 #define IPQ_LOCK() mtx_lock(&ipqlock) 166 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 167 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 168 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 169 170 static void maxnipq_update(void); 171 static void ipq_zone_change(void *); 172 173 static int maxnipq; /* Administrative limit on # reass queues. */ 174 static int nipq = 0; /* Total # of reass queues */ 175 SYSCTL_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, &nipq, 0, 176 "Current number of IPv4 fragment reassembly queue entries"); 177 178 static int maxfragsperpacket; 179 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 180 &maxfragsperpacket, 0, 181 "Maximum number of IPv4 fragments allowed per packet"); 182 183 struct callout ipport_tick_callout; 184 185 #ifdef IPCTL_DEFMTU 186 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 187 &ip_mtu, 0, "Default MTU"); 188 #endif 189 190 #ifdef IPSTEALTH 191 int ipstealth = 0; 192 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 193 &ipstealth, 0, ""); 194 #endif 195 196 /* 197 * ipfw_ether and ipfw_bridge hooks. 198 * XXX: Temporary until those are converted to pfil_hooks as well. 199 */ 200 ip_fw_chk_t *ip_fw_chk_ptr = NULL; 201 ip_dn_io_t *ip_dn_io_ptr = NULL; 202 int fw_one_pass = 1; 203 204 static void ip_freef(struct ipqhead *, struct ipq *); 205 206 /* 207 * IP initialization: fill in IP protocol switch table. 208 * All protocols not implemented in kernel go to raw IP protocol handler. 209 */ 210 void 211 ip_init() 212 { 213 register struct protosw *pr; 214 register int i; 215 216 TAILQ_INIT(&in_ifaddrhead); 217 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 218 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 219 if (pr == NULL) 220 panic("ip_init: PF_INET not found"); 221 222 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 223 for (i = 0; i < IPPROTO_MAX; i++) 224 ip_protox[i] = pr - inetsw; 225 /* 226 * Cycle through IP protocols and put them into the appropriate place 227 * in ip_protox[]. 228 */ 229 for (pr = inetdomain.dom_protosw; 230 pr < inetdomain.dom_protoswNPROTOSW; pr++) 231 if (pr->pr_domain->dom_family == PF_INET && 232 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 233 /* Be careful to only index valid IP protocols. */ 234 if (pr->pr_protocol < IPPROTO_MAX) 235 ip_protox[pr->pr_protocol] = pr - inetsw; 236 } 237 238 /* Initialize packet filter hooks. */ 239 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 240 inet_pfil_hook.ph_af = AF_INET; 241 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 242 printf("%s: WARNING: unable to register pfil hook, " 243 "error %d\n", __func__, i); 244 245 /* Initialize IP reassembly queue. */ 246 IPQ_LOCK_INIT(); 247 for (i = 0; i < IPREASS_NHASH; i++) 248 TAILQ_INIT(&ipq[i]); 249 maxnipq = nmbclusters / 32; 250 maxfragsperpacket = 16; 251 ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 252 NULL, UMA_ALIGN_PTR, 0); 253 maxnipq_update(); 254 255 /* Start ipport_tick. */ 256 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE); 257 ipport_tick(NULL); 258 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL, 259 SHUTDOWN_PRI_DEFAULT); 260 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, 261 NULL, EVENTHANDLER_PRI_ANY); 262 263 /* Initialize various other remaining things. */ 264 ip_id = time_second & 0xffff; 265 ipintrq.ifq_maxlen = ipqmaxlen; 266 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 267 netisr_register(NETISR_IP, ip_input, &ipintrq, NETISR_MPSAFE); 268 } 269 270 void ip_fini(xtp) 271 void *xtp; 272 { 273 callout_stop(&ipport_tick_callout); 274 } 275 276 /* 277 * Ip input routine. Checksum and byte swap header. If fragmented 278 * try to reassemble. Process options. Pass to next level. 279 */ 280 void 281 ip_input(struct mbuf *m) 282 { 283 struct ip *ip = NULL; 284 struct in_ifaddr *ia = NULL; 285 struct ifaddr *ifa; 286 int checkif, hlen = 0; 287 u_short sum; 288 int dchg = 0; /* dest changed after fw */ 289 struct in_addr odst; /* original dst address */ 290 291 M_ASSERTPKTHDR(m); 292 293 if (m->m_flags & M_FASTFWD_OURS) { 294 /* 295 * Firewall or NAT changed destination to local. 296 * We expect ip_len and ip_off to be in host byte order. 297 */ 298 m->m_flags &= ~M_FASTFWD_OURS; 299 /* Set up some basics that will be used later. */ 300 ip = mtod(m, struct ip *); 301 hlen = ip->ip_hl << 2; 302 goto ours; 303 } 304 305 ipstat.ips_total++; 306 307 if (m->m_pkthdr.len < sizeof(struct ip)) 308 goto tooshort; 309 310 if (m->m_len < sizeof (struct ip) && 311 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 312 ipstat.ips_toosmall++; 313 return; 314 } 315 ip = mtod(m, struct ip *); 316 317 if (ip->ip_v != IPVERSION) { 318 ipstat.ips_badvers++; 319 goto bad; 320 } 321 322 hlen = ip->ip_hl << 2; 323 if (hlen < sizeof(struct ip)) { /* minimum header length */ 324 ipstat.ips_badhlen++; 325 goto bad; 326 } 327 if (hlen > m->m_len) { 328 if ((m = m_pullup(m, hlen)) == NULL) { 329 ipstat.ips_badhlen++; 330 return; 331 } 332 ip = mtod(m, struct ip *); 333 } 334 335 /* 127/8 must not appear on wire - RFC1122 */ 336 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 337 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 338 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 339 ipstat.ips_badaddr++; 340 goto bad; 341 } 342 } 343 344 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 345 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 346 } else { 347 if (hlen == sizeof(struct ip)) { 348 sum = in_cksum_hdr(ip); 349 } else { 350 sum = in_cksum(m, hlen); 351 } 352 } 353 if (sum) { 354 ipstat.ips_badsum++; 355 goto bad; 356 } 357 358 #ifdef ALTQ 359 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 360 /* packet is dropped by traffic conditioner */ 361 return; 362 #endif 363 364 /* 365 * Convert fields to host representation. 366 */ 367 ip->ip_len = ntohs(ip->ip_len); 368 if (ip->ip_len < hlen) { 369 ipstat.ips_badlen++; 370 goto bad; 371 } 372 ip->ip_off = ntohs(ip->ip_off); 373 374 /* 375 * Check that the amount of data in the buffers 376 * is as at least much as the IP header would have us expect. 377 * Trim mbufs if longer than we expect. 378 * Drop packet if shorter than we expect. 379 */ 380 if (m->m_pkthdr.len < ip->ip_len) { 381 tooshort: 382 ipstat.ips_tooshort++; 383 goto bad; 384 } 385 if (m->m_pkthdr.len > ip->ip_len) { 386 if (m->m_len == m->m_pkthdr.len) { 387 m->m_len = ip->ip_len; 388 m->m_pkthdr.len = ip->ip_len; 389 } else 390 m_adj(m, ip->ip_len - m->m_pkthdr.len); 391 } 392 #if defined(IPSEC) || defined(FAST_IPSEC) 393 /* 394 * Bypass packet filtering for packets from a tunnel (gif). 395 */ 396 if (ip_ipsec_filtergif(m)) 397 goto passin; 398 #endif /* IPSEC */ 399 400 /* 401 * Run through list of hooks for input packets. 402 * 403 * NB: Beware of the destination address changing (e.g. 404 * by NAT rewriting). When this happens, tell 405 * ip_forward to do the right thing. 406 */ 407 408 /* Jump over all PFIL processing if hooks are not active. */ 409 if (!PFIL_HOOKED(&inet_pfil_hook)) 410 goto passin; 411 412 odst = ip->ip_dst; 413 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 414 PFIL_IN, NULL) != 0) 415 return; 416 if (m == NULL) /* consumed by filter */ 417 return; 418 419 ip = mtod(m, struct ip *); 420 dchg = (odst.s_addr != ip->ip_dst.s_addr); 421 422 #ifdef IPFIREWALL_FORWARD 423 if (m->m_flags & M_FASTFWD_OURS) { 424 m->m_flags &= ~M_FASTFWD_OURS; 425 goto ours; 426 } 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 */ 437 438 passin: 439 /* 440 * Process options and, if not destined for us, 441 * ship it on. ip_dooptions returns 1 when an 442 * error was detected (causing an icmp message 443 * to be sent and the original packet to be freed). 444 */ 445 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 446 return; 447 448 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 449 * matter if it is destined to another node, or whether it is 450 * a multicast one, RSVP wants it! and prevents it from being forwarded 451 * anywhere else. Also checks if the rsvp daemon is running before 452 * grabbing the packet. 453 */ 454 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 455 goto ours; 456 457 /* 458 * Check our list of addresses, to see if the packet is for us. 459 * If we don't have any addresses, assume any unicast packet 460 * we receive might be for us (and let the upper layers deal 461 * with it). 462 */ 463 if (TAILQ_EMPTY(&in_ifaddrhead) && 464 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 465 goto ours; 466 467 /* 468 * Enable a consistency check between the destination address 469 * and the arrival interface for a unicast packet (the RFC 1122 470 * strong ES model) if IP forwarding is disabled and the packet 471 * is not locally generated and the packet is not subject to 472 * 'ipfw fwd'. 473 * 474 * XXX - Checking also should be disabled if the destination 475 * address is ipnat'ed to a different interface. 476 * 477 * XXX - Checking is incompatible with IP aliases added 478 * to the loopback interface instead of the interface where 479 * the packets are received. 480 * 481 * XXX - This is the case for carp vhost IPs as well so we 482 * insert a workaround. If the packet got here, we already 483 * checked with carp_iamatch() and carp_forus(). 484 */ 485 checkif = ip_checkinterface && (ipforwarding == 0) && 486 m->m_pkthdr.rcvif != NULL && 487 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 488 #ifdef DEV_CARP 489 !m->m_pkthdr.rcvif->if_carp && 490 #endif 491 (dchg == 0); 492 493 /* 494 * Check for exact addresses in the hash bucket. 495 */ 496 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 497 /* 498 * If the address matches, verify that the packet 499 * arrived via the correct interface if checking is 500 * enabled. 501 */ 502 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 503 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 504 goto ours; 505 } 506 /* 507 * Check for broadcast addresses. 508 * 509 * Only accept broadcast packets that arrive via the matching 510 * interface. Reception of forwarded directed broadcasts would 511 * be handled via ip_forward() and ether_output() with the loopback 512 * into the stack for SIMPLEX interfaces handled by ether_output(). 513 */ 514 if (m->m_pkthdr.rcvif != NULL && 515 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 516 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 517 if (ifa->ifa_addr->sa_family != AF_INET) 518 continue; 519 ia = ifatoia(ifa); 520 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 521 ip->ip_dst.s_addr) 522 goto ours; 523 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 524 goto ours; 525 #ifdef BOOTP_COMPAT 526 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 527 goto ours; 528 #endif 529 } 530 } 531 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 532 struct in_multi *inm; 533 if (ip_mrouter) { 534 /* 535 * If we are acting as a multicast router, all 536 * incoming multicast packets are passed to the 537 * kernel-level multicast forwarding function. 538 * The packet is returned (relatively) intact; if 539 * ip_mforward() returns a non-zero value, the packet 540 * must be discarded, else it may be accepted below. 541 */ 542 if (ip_mforward && 543 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 544 ipstat.ips_cantforward++; 545 m_freem(m); 546 return; 547 } 548 549 /* 550 * The process-level routing daemon needs to receive 551 * all multicast IGMP packets, whether or not this 552 * host belongs to their destination groups. 553 */ 554 if (ip->ip_p == IPPROTO_IGMP) 555 goto ours; 556 ipstat.ips_forward++; 557 } 558 /* 559 * See if we belong to the destination multicast group on the 560 * arrival interface. 561 */ 562 IN_MULTI_LOCK(); 563 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 564 IN_MULTI_UNLOCK(); 565 if (inm == NULL) { 566 ipstat.ips_notmember++; 567 m_freem(m); 568 return; 569 } 570 goto ours; 571 } 572 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 573 goto ours; 574 if (ip->ip_dst.s_addr == INADDR_ANY) 575 goto ours; 576 577 /* 578 * FAITH(Firewall Aided Internet Translator) 579 */ 580 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 581 if (ip_keepfaith) { 582 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 583 goto ours; 584 } 585 m_freem(m); 586 return; 587 } 588 589 /* 590 * Not for us; forward if possible and desirable. 591 */ 592 if (ipforwarding == 0) { 593 ipstat.ips_cantforward++; 594 m_freem(m); 595 } else { 596 #if defined(IPSEC) || defined(FAST_IPSEC) 597 if (ip_ipsec_fwd(m)) 598 goto bad; 599 #endif /* IPSEC */ 600 ip_forward(m, dchg); 601 } 602 return; 603 604 ours: 605 #ifdef IPSTEALTH 606 /* 607 * IPSTEALTH: Process non-routing options only 608 * if the packet is destined for us. 609 */ 610 if (ipstealth && hlen > sizeof (struct ip) && 611 ip_dooptions(m, 1)) 612 return; 613 #endif /* IPSTEALTH */ 614 615 /* Count the packet in the ip address stats */ 616 if (ia != NULL) { 617 ia->ia_ifa.if_ipackets++; 618 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 619 } 620 621 /* 622 * Attempt reassembly; if it succeeds, proceed. 623 * ip_reass() will return a different mbuf. 624 */ 625 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 626 m = ip_reass(m); 627 if (m == NULL) 628 return; 629 ip = mtod(m, struct ip *); 630 /* Get the header length of the reassembled packet */ 631 hlen = ip->ip_hl << 2; 632 } 633 634 /* 635 * Further protocols expect the packet length to be w/o the 636 * IP header. 637 */ 638 ip->ip_len -= hlen; 639 640 #if defined(IPSEC) || defined(FAST_IPSEC) 641 /* 642 * enforce IPsec policy checking if we are seeing last header. 643 * note that we do not visit this with protocols with pcb layer 644 * code - like udp/tcp/raw ip. 645 */ 646 if (ip_ipsec_input(m)) 647 goto bad; 648 #endif /* IPSEC */ 649 650 /* 651 * Switch out to protocol's input routine. 652 */ 653 ipstat.ips_delivered++; 654 655 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 656 return; 657 bad: 658 m_freem(m); 659 } 660 661 /* 662 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 663 * max has slightly different semantics than the sysctl, for historical 664 * reasons. 665 */ 666 static void 667 maxnipq_update(void) 668 { 669 670 /* 671 * -1 for unlimited allocation. 672 */ 673 if (maxnipq < 0) 674 uma_zone_set_max(ipq_zone, 0); 675 /* 676 * Positive number for specific bound. 677 */ 678 if (maxnipq > 0) 679 uma_zone_set_max(ipq_zone, maxnipq); 680 /* 681 * Zero specifies no further fragment queue allocation -- set the 682 * bound very low, but rely on implementation elsewhere to actually 683 * prevent allocation and reclaim current queues. 684 */ 685 if (maxnipq == 0) 686 uma_zone_set_max(ipq_zone, 1); 687 } 688 689 static void 690 ipq_zone_change(void *tag) 691 { 692 693 if (maxnipq > 0 && maxnipq < (nmbclusters / 32)) { 694 maxnipq = nmbclusters / 32; 695 maxnipq_update(); 696 } 697 } 698 699 static int 700 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 701 { 702 int error, i; 703 704 i = maxnipq; 705 error = sysctl_handle_int(oidp, &i, 0, req); 706 if (error || !req->newptr) 707 return (error); 708 709 /* 710 * XXXRW: Might be a good idea to sanity check the argument and place 711 * an extreme upper bound. 712 */ 713 if (i < -1) 714 return (EINVAL); 715 maxnipq = i; 716 maxnipq_update(); 717 return (0); 718 } 719 720 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 721 NULL, 0, sysctl_maxnipq, "I", 722 "Maximum number of IPv4 fragment reassembly queue entries"); 723 724 /* 725 * Take incoming datagram fragment and try to reassemble it into 726 * whole datagram. If the argument is the first fragment or one 727 * in between the function will return NULL and store the mbuf 728 * in the fragment chain. If the argument is the last fragment 729 * the packet will be reassembled and the pointer to the new 730 * mbuf returned for further processing. Only m_tags attached 731 * to the first packet/fragment are preserved. 732 * The IP header is *NOT* adjusted out of iplen. 733 */ 734 735 struct mbuf * 736 ip_reass(struct mbuf *m) 737 { 738 struct ip *ip; 739 struct mbuf *p, *q, *nq, *t; 740 struct ipq *fp = NULL; 741 struct ipqhead *head; 742 int i, hlen, next; 743 u_int8_t ecn, ecn0; 744 u_short hash; 745 746 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 747 if (maxnipq == 0 || maxfragsperpacket == 0) { 748 ipstat.ips_fragments++; 749 ipstat.ips_fragdropped++; 750 m_freem(m); 751 return (NULL); 752 } 753 754 ip = mtod(m, struct ip *); 755 hlen = ip->ip_hl << 2; 756 757 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 758 head = &ipq[hash]; 759 IPQ_LOCK(); 760 761 /* 762 * Look for queue of fragments 763 * of this datagram. 764 */ 765 TAILQ_FOREACH(fp, head, ipq_list) 766 if (ip->ip_id == fp->ipq_id && 767 ip->ip_src.s_addr == fp->ipq_src.s_addr && 768 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 769 #ifdef MAC 770 mac_fragment_match(m, fp) && 771 #endif 772 ip->ip_p == fp->ipq_p) 773 goto found; 774 775 fp = NULL; 776 777 /* 778 * Attempt to trim the number of allocated fragment queues if it 779 * exceeds the administrative limit. 780 */ 781 if ((nipq > maxnipq) && (maxnipq > 0)) { 782 /* 783 * drop something from the tail of the current queue 784 * before proceeding further 785 */ 786 struct ipq *q = TAILQ_LAST(head, ipqhead); 787 if (q == NULL) { /* gak */ 788 for (i = 0; i < IPREASS_NHASH; i++) { 789 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 790 if (r) { 791 ipstat.ips_fragtimeout += r->ipq_nfrags; 792 ip_freef(&ipq[i], r); 793 break; 794 } 795 } 796 } else { 797 ipstat.ips_fragtimeout += q->ipq_nfrags; 798 ip_freef(head, q); 799 } 800 } 801 802 found: 803 /* 804 * Adjust ip_len to not reflect header, 805 * convert offset of this to bytes. 806 */ 807 ip->ip_len -= hlen; 808 if (ip->ip_off & IP_MF) { 809 /* 810 * Make sure that fragments have a data length 811 * that's a non-zero multiple of 8 bytes. 812 */ 813 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 814 ipstat.ips_toosmall++; /* XXX */ 815 goto dropfrag; 816 } 817 m->m_flags |= M_FRAG; 818 } else 819 m->m_flags &= ~M_FRAG; 820 ip->ip_off <<= 3; 821 822 823 /* 824 * Attempt reassembly; if it succeeds, proceed. 825 * ip_reass() will return a different mbuf. 826 */ 827 ipstat.ips_fragments++; 828 m->m_pkthdr.header = ip; 829 830 /* Previous ip_reass() started here. */ 831 /* 832 * Presence of header sizes in mbufs 833 * would confuse code below. 834 */ 835 m->m_data += hlen; 836 m->m_len -= hlen; 837 838 /* 839 * If first fragment to arrive, create a reassembly queue. 840 */ 841 if (fp == NULL) { 842 fp = uma_zalloc(ipq_zone, M_NOWAIT); 843 if (fp == NULL) 844 goto dropfrag; 845 #ifdef MAC 846 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 847 uma_zfree(ipq_zone, fp); 848 fp = NULL; 849 goto dropfrag; 850 } 851 mac_create_ipq(m, fp); 852 #endif 853 TAILQ_INSERT_HEAD(head, fp, ipq_list); 854 nipq++; 855 fp->ipq_nfrags = 1; 856 fp->ipq_ttl = IPFRAGTTL; 857 fp->ipq_p = ip->ip_p; 858 fp->ipq_id = ip->ip_id; 859 fp->ipq_src = ip->ip_src; 860 fp->ipq_dst = ip->ip_dst; 861 fp->ipq_frags = m; 862 m->m_nextpkt = NULL; 863 goto done; 864 } else { 865 fp->ipq_nfrags++; 866 #ifdef MAC 867 mac_update_ipq(m, fp); 868 #endif 869 } 870 871 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 872 873 /* 874 * Handle ECN by comparing this segment with the first one; 875 * if CE is set, do not lose CE. 876 * drop if CE and not-ECT are mixed for the same packet. 877 */ 878 ecn = ip->ip_tos & IPTOS_ECN_MASK; 879 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 880 if (ecn == IPTOS_ECN_CE) { 881 if (ecn0 == IPTOS_ECN_NOTECT) 882 goto dropfrag; 883 if (ecn0 != IPTOS_ECN_CE) 884 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 885 } 886 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 887 goto dropfrag; 888 889 /* 890 * Find a segment which begins after this one does. 891 */ 892 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 893 if (GETIP(q)->ip_off > ip->ip_off) 894 break; 895 896 /* 897 * If there is a preceding segment, it may provide some of 898 * our data already. If so, drop the data from the incoming 899 * segment. If it provides all of our data, drop us, otherwise 900 * stick new segment in the proper place. 901 * 902 * If some of the data is dropped from the the preceding 903 * segment, then it's checksum is invalidated. 904 */ 905 if (p) { 906 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 907 if (i > 0) { 908 if (i >= ip->ip_len) 909 goto dropfrag; 910 m_adj(m, i); 911 m->m_pkthdr.csum_flags = 0; 912 ip->ip_off += i; 913 ip->ip_len -= i; 914 } 915 m->m_nextpkt = p->m_nextpkt; 916 p->m_nextpkt = m; 917 } else { 918 m->m_nextpkt = fp->ipq_frags; 919 fp->ipq_frags = m; 920 } 921 922 /* 923 * While we overlap succeeding segments trim them or, 924 * if they are completely covered, dequeue them. 925 */ 926 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 927 q = nq) { 928 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 929 if (i < GETIP(q)->ip_len) { 930 GETIP(q)->ip_len -= i; 931 GETIP(q)->ip_off += i; 932 m_adj(q, i); 933 q->m_pkthdr.csum_flags = 0; 934 break; 935 } 936 nq = q->m_nextpkt; 937 m->m_nextpkt = nq; 938 ipstat.ips_fragdropped++; 939 fp->ipq_nfrags--; 940 m_freem(q); 941 } 942 943 /* 944 * Check for complete reassembly and perform frag per packet 945 * limiting. 946 * 947 * Frag limiting is performed here so that the nth frag has 948 * a chance to complete the packet before we drop the packet. 949 * As a result, n+1 frags are actually allowed per packet, but 950 * only n will ever be stored. (n = maxfragsperpacket.) 951 * 952 */ 953 next = 0; 954 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 955 if (GETIP(q)->ip_off != next) { 956 if (fp->ipq_nfrags > maxfragsperpacket) { 957 ipstat.ips_fragdropped += fp->ipq_nfrags; 958 ip_freef(head, fp); 959 } 960 goto done; 961 } 962 next += GETIP(q)->ip_len; 963 } 964 /* Make sure the last packet didn't have the IP_MF flag */ 965 if (p->m_flags & M_FRAG) { 966 if (fp->ipq_nfrags > maxfragsperpacket) { 967 ipstat.ips_fragdropped += fp->ipq_nfrags; 968 ip_freef(head, fp); 969 } 970 goto done; 971 } 972 973 /* 974 * Reassembly is complete. Make sure the packet is a sane size. 975 */ 976 q = fp->ipq_frags; 977 ip = GETIP(q); 978 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 979 ipstat.ips_toolong++; 980 ipstat.ips_fragdropped += fp->ipq_nfrags; 981 ip_freef(head, fp); 982 goto done; 983 } 984 985 /* 986 * Concatenate fragments. 987 */ 988 m = q; 989 t = m->m_next; 990 m->m_next = NULL; 991 m_cat(m, t); 992 nq = q->m_nextpkt; 993 q->m_nextpkt = NULL; 994 for (q = nq; q != NULL; q = nq) { 995 nq = q->m_nextpkt; 996 q->m_nextpkt = NULL; 997 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 998 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 999 m_cat(m, q); 1000 } 1001 /* 1002 * In order to do checksumming faster we do 'end-around carry' here 1003 * (and not in for{} loop), though it implies we are not going to 1004 * reassemble more than 64k fragments. 1005 */ 1006 m->m_pkthdr.csum_data = 1007 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1008 #ifdef MAC 1009 mac_create_datagram_from_ipq(fp, m); 1010 mac_destroy_ipq(fp); 1011 #endif 1012 1013 /* 1014 * Create header for new ip packet by modifying header of first 1015 * packet; dequeue and discard fragment reassembly header. 1016 * Make header visible. 1017 */ 1018 ip->ip_len = (ip->ip_hl << 2) + next; 1019 ip->ip_src = fp->ipq_src; 1020 ip->ip_dst = fp->ipq_dst; 1021 TAILQ_REMOVE(head, fp, ipq_list); 1022 nipq--; 1023 uma_zfree(ipq_zone, fp); 1024 m->m_len += (ip->ip_hl << 2); 1025 m->m_data -= (ip->ip_hl << 2); 1026 /* some debugging cruft by sklower, below, will go away soon */ 1027 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1028 m_fixhdr(m); 1029 ipstat.ips_reassembled++; 1030 IPQ_UNLOCK(); 1031 return (m); 1032 1033 dropfrag: 1034 ipstat.ips_fragdropped++; 1035 if (fp != NULL) 1036 fp->ipq_nfrags--; 1037 m_freem(m); 1038 done: 1039 IPQ_UNLOCK(); 1040 return (NULL); 1041 1042 #undef GETIP 1043 } 1044 1045 /* 1046 * Free a fragment reassembly header and all 1047 * associated datagrams. 1048 */ 1049 static void 1050 ip_freef(fhp, fp) 1051 struct ipqhead *fhp; 1052 struct ipq *fp; 1053 { 1054 register struct mbuf *q; 1055 1056 IPQ_LOCK_ASSERT(); 1057 1058 while (fp->ipq_frags) { 1059 q = fp->ipq_frags; 1060 fp->ipq_frags = q->m_nextpkt; 1061 m_freem(q); 1062 } 1063 TAILQ_REMOVE(fhp, fp, ipq_list); 1064 uma_zfree(ipq_zone, fp); 1065 nipq--; 1066 } 1067 1068 /* 1069 * IP timer processing; 1070 * if a timer expires on a reassembly 1071 * queue, discard it. 1072 */ 1073 void 1074 ip_slowtimo() 1075 { 1076 register struct ipq *fp; 1077 int i; 1078 1079 IPQ_LOCK(); 1080 for (i = 0; i < IPREASS_NHASH; i++) { 1081 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1082 struct ipq *fpp; 1083 1084 fpp = fp; 1085 fp = TAILQ_NEXT(fp, ipq_list); 1086 if(--fpp->ipq_ttl == 0) { 1087 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1088 ip_freef(&ipq[i], fpp); 1089 } 1090 } 1091 } 1092 /* 1093 * If we are over the maximum number of fragments 1094 * (due to the limit being lowered), drain off 1095 * enough to get down to the new limit. 1096 */ 1097 if (maxnipq >= 0 && nipq > maxnipq) { 1098 for (i = 0; i < IPREASS_NHASH; i++) { 1099 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1100 ipstat.ips_fragdropped += 1101 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1102 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1103 } 1104 } 1105 } 1106 IPQ_UNLOCK(); 1107 } 1108 1109 /* 1110 * Drain off all datagram fragments. 1111 */ 1112 void 1113 ip_drain() 1114 { 1115 int i; 1116 1117 IPQ_LOCK(); 1118 for (i = 0; i < IPREASS_NHASH; i++) { 1119 while(!TAILQ_EMPTY(&ipq[i])) { 1120 ipstat.ips_fragdropped += 1121 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1122 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1123 } 1124 } 1125 IPQ_UNLOCK(); 1126 in_rtqdrain(); 1127 } 1128 1129 /* 1130 * The protocol to be inserted into ip_protox[] must be already registered 1131 * in inetsw[], either statically or through pf_proto_register(). 1132 */ 1133 int 1134 ipproto_register(u_char ipproto) 1135 { 1136 struct protosw *pr; 1137 1138 /* Sanity checks. */ 1139 if (ipproto == 0) 1140 return (EPROTONOSUPPORT); 1141 1142 /* 1143 * The protocol slot must not be occupied by another protocol 1144 * already. An index pointing to IPPROTO_RAW is unused. 1145 */ 1146 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1147 if (pr == NULL) 1148 return (EPFNOSUPPORT); 1149 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1150 return (EEXIST); 1151 1152 /* Find the protocol position in inetsw[] and set the index. */ 1153 for (pr = inetdomain.dom_protosw; 1154 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1155 if (pr->pr_domain->dom_family == PF_INET && 1156 pr->pr_protocol && pr->pr_protocol == ipproto) { 1157 /* Be careful to only index valid IP protocols. */ 1158 if (pr->pr_protocol < IPPROTO_MAX) { 1159 ip_protox[pr->pr_protocol] = pr - inetsw; 1160 return (0); 1161 } else 1162 return (EINVAL); 1163 } 1164 } 1165 return (EPROTONOSUPPORT); 1166 } 1167 1168 int 1169 ipproto_unregister(u_char ipproto) 1170 { 1171 struct protosw *pr; 1172 1173 /* Sanity checks. */ 1174 if (ipproto == 0) 1175 return (EPROTONOSUPPORT); 1176 1177 /* Check if the protocol was indeed registered. */ 1178 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1179 if (pr == NULL) 1180 return (EPFNOSUPPORT); 1181 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1182 return (ENOENT); 1183 1184 /* Reset the protocol slot to IPPROTO_RAW. */ 1185 ip_protox[ipproto] = pr - inetsw; 1186 return (0); 1187 } 1188 1189 /* 1190 * Given address of next destination (final or next hop), 1191 * return internet address info of interface to be used to get there. 1192 */ 1193 struct in_ifaddr * 1194 ip_rtaddr(dst) 1195 struct in_addr dst; 1196 { 1197 struct route sro; 1198 struct sockaddr_in *sin; 1199 struct in_ifaddr *ifa; 1200 1201 bzero(&sro, sizeof(sro)); 1202 sin = (struct sockaddr_in *)&sro.ro_dst; 1203 sin->sin_family = AF_INET; 1204 sin->sin_len = sizeof(*sin); 1205 sin->sin_addr = dst; 1206 rtalloc_ign(&sro, RTF_CLONING); 1207 1208 if (sro.ro_rt == NULL) 1209 return (NULL); 1210 1211 ifa = ifatoia(sro.ro_rt->rt_ifa); 1212 RTFREE(sro.ro_rt); 1213 return (ifa); 1214 } 1215 1216 u_char inetctlerrmap[PRC_NCMDS] = { 1217 0, 0, 0, 0, 1218 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1219 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1220 EMSGSIZE, EHOSTUNREACH, 0, 0, 1221 0, 0, EHOSTUNREACH, 0, 1222 ENOPROTOOPT, ECONNREFUSED 1223 }; 1224 1225 /* 1226 * Forward a packet. If some error occurs return the sender 1227 * an icmp packet. Note we can't always generate a meaningful 1228 * icmp message because icmp doesn't have a large enough repertoire 1229 * of codes and types. 1230 * 1231 * If not forwarding, just drop the packet. This could be confusing 1232 * if ipforwarding was zero but some routing protocol was advancing 1233 * us as a gateway to somewhere. However, we must let the routing 1234 * protocol deal with that. 1235 * 1236 * The srcrt parameter indicates whether the packet is being forwarded 1237 * via a source route. 1238 */ 1239 void 1240 ip_forward(struct mbuf *m, int srcrt) 1241 { 1242 struct ip *ip = mtod(m, struct ip *); 1243 struct in_ifaddr *ia = NULL; 1244 struct mbuf *mcopy; 1245 struct in_addr dest; 1246 int error, type = 0, code = 0, mtu = 0; 1247 1248 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1249 ipstat.ips_cantforward++; 1250 m_freem(m); 1251 return; 1252 } 1253 #ifdef IPSTEALTH 1254 if (!ipstealth) { 1255 #endif 1256 if (ip->ip_ttl <= IPTTLDEC) { 1257 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1258 0, 0); 1259 return; 1260 } 1261 #ifdef IPSTEALTH 1262 } 1263 #endif 1264 1265 if (!srcrt && (ia = ip_rtaddr(ip->ip_dst)) == NULL) { 1266 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1267 return; 1268 } 1269 1270 /* 1271 * Save the IP header and at most 8 bytes of the payload, 1272 * in case we need to generate an ICMP message to the src. 1273 * 1274 * XXX this can be optimized a lot by saving the data in a local 1275 * buffer on the stack (72 bytes at most), and only allocating the 1276 * mbuf if really necessary. The vast majority of the packets 1277 * are forwarded without having to send an ICMP back (either 1278 * because unnecessary, or because rate limited), so we are 1279 * really we are wasting a lot of work here. 1280 * 1281 * We don't use m_copy() because it might return a reference 1282 * to a shared cluster. Both this function and ip_output() 1283 * assume exclusive access to the IP header in `m', so any 1284 * data in a cluster may change before we reach icmp_error(). 1285 */ 1286 MGETHDR(mcopy, M_DONTWAIT, m->m_type); 1287 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1288 /* 1289 * It's probably ok if the pkthdr dup fails (because 1290 * the deep copy of the tag chain failed), but for now 1291 * be conservative and just discard the copy since 1292 * code below may some day want the tags. 1293 */ 1294 m_free(mcopy); 1295 mcopy = NULL; 1296 } 1297 if (mcopy != NULL) { 1298 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy)); 1299 mcopy->m_pkthdr.len = mcopy->m_len; 1300 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1301 } 1302 1303 #ifdef IPSTEALTH 1304 if (!ipstealth) { 1305 #endif 1306 ip->ip_ttl -= IPTTLDEC; 1307 #ifdef IPSTEALTH 1308 } 1309 #endif 1310 1311 /* 1312 * If forwarding packet using same interface that it came in on, 1313 * perhaps should send a redirect to sender to shortcut a hop. 1314 * Only send redirect if source is sending directly to us, 1315 * and if packet was not source routed (or has any options). 1316 * Also, don't send redirect if forwarding using a default route 1317 * or a route modified by a redirect. 1318 */ 1319 dest.s_addr = 0; 1320 if (!srcrt && ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1321 struct sockaddr_in *sin; 1322 struct route ro; 1323 struct rtentry *rt; 1324 1325 bzero(&ro, sizeof(ro)); 1326 sin = (struct sockaddr_in *)&ro.ro_dst; 1327 sin->sin_family = AF_INET; 1328 sin->sin_len = sizeof(*sin); 1329 sin->sin_addr = ip->ip_dst; 1330 rtalloc_ign(&ro, RTF_CLONING); 1331 1332 rt = ro.ro_rt; 1333 1334 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1335 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1336 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1337 u_long src = ntohl(ip->ip_src.s_addr); 1338 1339 if (RTA(rt) && 1340 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1341 if (rt->rt_flags & RTF_GATEWAY) 1342 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1343 else 1344 dest.s_addr = ip->ip_dst.s_addr; 1345 /* Router requirements says to only send host redirects */ 1346 type = ICMP_REDIRECT; 1347 code = ICMP_REDIRECT_HOST; 1348 } 1349 } 1350 if (rt) 1351 RTFREE(rt); 1352 } 1353 1354 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 1355 if (error) 1356 ipstat.ips_cantforward++; 1357 else { 1358 ipstat.ips_forward++; 1359 if (type) 1360 ipstat.ips_redirectsent++; 1361 else { 1362 if (mcopy) 1363 m_freem(mcopy); 1364 return; 1365 } 1366 } 1367 if (mcopy == NULL) 1368 return; 1369 1370 switch (error) { 1371 1372 case 0: /* forwarded, but need redirect */ 1373 /* type, code set above */ 1374 break; 1375 1376 case ENETUNREACH: /* shouldn't happen, checked above */ 1377 case EHOSTUNREACH: 1378 case ENETDOWN: 1379 case EHOSTDOWN: 1380 default: 1381 type = ICMP_UNREACH; 1382 code = ICMP_UNREACH_HOST; 1383 break; 1384 1385 case EMSGSIZE: 1386 type = ICMP_UNREACH; 1387 code = ICMP_UNREACH_NEEDFRAG; 1388 1389 #if defined(IPSEC) || defined(FAST_IPSEC) 1390 mtu = ip_ipsec_mtu(m); 1391 #endif /* IPSEC */ 1392 /* 1393 * If the MTU wasn't set before use the interface mtu or 1394 * fall back to the next smaller mtu step compared to the 1395 * current packet size. 1396 */ 1397 if (mtu == 0) { 1398 if (ia != NULL) 1399 mtu = ia->ia_ifp->if_mtu; 1400 else 1401 mtu = ip_next_mtu(ip->ip_len, 0); 1402 } 1403 ipstat.ips_cantfrag++; 1404 break; 1405 1406 case ENOBUFS: 1407 /* 1408 * A router should not generate ICMP_SOURCEQUENCH as 1409 * required in RFC1812 Requirements for IP Version 4 Routers. 1410 * Source quench could be a big problem under DoS attacks, 1411 * or if the underlying interface is rate-limited. 1412 * Those who need source quench packets may re-enable them 1413 * via the net.inet.ip.sendsourcequench sysctl. 1414 */ 1415 if (ip_sendsourcequench == 0) { 1416 m_freem(mcopy); 1417 return; 1418 } else { 1419 type = ICMP_SOURCEQUENCH; 1420 code = 0; 1421 } 1422 break; 1423 1424 case EACCES: /* ipfw denied packet */ 1425 m_freem(mcopy); 1426 return; 1427 } 1428 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1429 } 1430 1431 void 1432 ip_savecontrol(inp, mp, ip, m) 1433 register struct inpcb *inp; 1434 register struct mbuf **mp; 1435 register struct ip *ip; 1436 register struct mbuf *m; 1437 { 1438 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1439 struct bintime bt; 1440 1441 bintime(&bt); 1442 if (inp->inp_socket->so_options & SO_BINTIME) { 1443 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 1444 SCM_BINTIME, SOL_SOCKET); 1445 if (*mp) 1446 mp = &(*mp)->m_next; 1447 } 1448 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1449 struct timeval tv; 1450 1451 bintime2timeval(&bt, &tv); 1452 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1453 SCM_TIMESTAMP, SOL_SOCKET); 1454 if (*mp) 1455 mp = &(*mp)->m_next; 1456 } 1457 } 1458 if (inp->inp_flags & INP_RECVDSTADDR) { 1459 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1460 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1461 if (*mp) 1462 mp = &(*mp)->m_next; 1463 } 1464 if (inp->inp_flags & INP_RECVTTL) { 1465 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1466 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1467 if (*mp) 1468 mp = &(*mp)->m_next; 1469 } 1470 #ifdef notyet 1471 /* XXX 1472 * Moving these out of udp_input() made them even more broken 1473 * than they already were. 1474 */ 1475 /* options were tossed already */ 1476 if (inp->inp_flags & INP_RECVOPTS) { 1477 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1478 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1479 if (*mp) 1480 mp = &(*mp)->m_next; 1481 } 1482 /* ip_srcroute doesn't do what we want here, need to fix */ 1483 if (inp->inp_flags & INP_RECVRETOPTS) { 1484 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1485 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1486 if (*mp) 1487 mp = &(*mp)->m_next; 1488 } 1489 #endif 1490 if (inp->inp_flags & INP_RECVIF) { 1491 struct ifnet *ifp; 1492 struct sdlbuf { 1493 struct sockaddr_dl sdl; 1494 u_char pad[32]; 1495 } sdlbuf; 1496 struct sockaddr_dl *sdp; 1497 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1498 1499 if (((ifp = m->m_pkthdr.rcvif)) 1500 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1501 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1502 /* 1503 * Change our mind and don't try copy. 1504 */ 1505 if ((sdp->sdl_family != AF_LINK) 1506 || (sdp->sdl_len > sizeof(sdlbuf))) { 1507 goto makedummy; 1508 } 1509 bcopy(sdp, sdl2, sdp->sdl_len); 1510 } else { 1511 makedummy: 1512 sdl2->sdl_len 1513 = offsetof(struct sockaddr_dl, sdl_data[0]); 1514 sdl2->sdl_family = AF_LINK; 1515 sdl2->sdl_index = 0; 1516 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1517 } 1518 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1519 IP_RECVIF, IPPROTO_IP); 1520 if (*mp) 1521 mp = &(*mp)->m_next; 1522 } 1523 } 1524 1525 /* 1526 * XXX these routines are called from the upper part of the kernel. 1527 * They need to be locked when we remove Giant. 1528 * 1529 * They could also be moved to ip_mroute.c, since all the RSVP 1530 * handling is done there already. 1531 */ 1532 static int ip_rsvp_on; 1533 struct socket *ip_rsvpd; 1534 int 1535 ip_rsvp_init(struct socket *so) 1536 { 1537 if (so->so_type != SOCK_RAW || 1538 so->so_proto->pr_protocol != IPPROTO_RSVP) 1539 return EOPNOTSUPP; 1540 1541 if (ip_rsvpd != NULL) 1542 return EADDRINUSE; 1543 1544 ip_rsvpd = so; 1545 /* 1546 * This may seem silly, but we need to be sure we don't over-increment 1547 * the RSVP counter, in case something slips up. 1548 */ 1549 if (!ip_rsvp_on) { 1550 ip_rsvp_on = 1; 1551 rsvp_on++; 1552 } 1553 1554 return 0; 1555 } 1556 1557 int 1558 ip_rsvp_done(void) 1559 { 1560 ip_rsvpd = NULL; 1561 /* 1562 * This may seem silly, but we need to be sure we don't over-decrement 1563 * the RSVP counter, in case something slips up. 1564 */ 1565 if (ip_rsvp_on) { 1566 ip_rsvp_on = 0; 1567 rsvp_on--; 1568 } 1569 return 0; 1570 } 1571 1572 void 1573 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1574 { 1575 if (rsvp_input_p) { /* call the real one if loaded */ 1576 rsvp_input_p(m, off); 1577 return; 1578 } 1579 1580 /* Can still get packets with rsvp_on = 0 if there is a local member 1581 * of the group to which the RSVP packet is addressed. But in this 1582 * case we want to throw the packet away. 1583 */ 1584 1585 if (!rsvp_on) { 1586 m_freem(m); 1587 return; 1588 } 1589 1590 if (ip_rsvpd != NULL) { 1591 rip_input(m, off); 1592 return; 1593 } 1594 /* Drop the packet */ 1595 m_freem(m); 1596 } 1597