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: head/sys/netinet/ip_input.c 155425 2006-02-07 11:48:10Z oleg $
|
30 * $FreeBSD: head/sys/netinet/ip_input.c 157927 2006-04-21 09:25:40Z ps $ |
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 84int rsvp_on = 0; 85 86int ipforwarding = 0; 87SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 88 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 89 90static int ipsendredirects = 1; /* XXX */ 91SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 92 &ipsendredirects, 0, "Enable sending IP redirects"); 93 94int ip_defttl = IPDEFTTL; 95SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 96 &ip_defttl, 0, "Maximum TTL on IP packets"); 97 98static int ip_keepfaith = 0; 99SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 100 &ip_keepfaith, 0, 101 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 102 103static int ip_sendsourcequench = 0; 104SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 105 &ip_sendsourcequench, 0, 106 "Enable the transmission of source quench packets"); 107 108int ip_do_randomid = 0; 109SYSCTL_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 */ 126static int ip_checkinterface = 0; 127SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 128 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 129 130struct pfil_head inet_pfil_hook; /* Packet filter hooks */ 131 132static struct ifqueue ipintrq; 133static int ipqmaxlen = IFQ_MAXLEN; 134 135extern struct domain inetdomain; 136extern struct protosw inetsw[]; 137u_char ip_protox[IPPROTO_MAX]; 138struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 139struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 140u_long in_ifaddrhmask; /* mask for hash table */ 141 142SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 143 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 144SYSCTL_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 147struct ipstat ipstat; 148SYSCTL_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 160static uma_zone_t ipq_zone; 161static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 162static 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 169static void maxnipq_update(void);
|
170static void ipq_zone_change(void *); |
171 172static int maxnipq; /* Administrative limit on # reass queues. */ 173static int nipq = 0; /* Total # of reass queues */ 174SYSCTL_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, &nipq, 0, 175 "Current number of IPv4 fragment reassembly queue entries"); 176 177static int maxfragsperpacket; 178SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 179 &maxfragsperpacket, 0, 180 "Maximum number of IPv4 fragments allowed per packet"); 181 182struct callout ipport_tick_callout; 183 184#ifdef IPCTL_DEFMTU 185SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 186 &ip_mtu, 0, "Default MTU"); 187#endif 188 189#ifdef IPSTEALTH 190int ipstealth = 0; 191SYSCTL_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 */ 199ip_fw_chk_t *ip_fw_chk_ptr = NULL; 200ip_dn_io_t *ip_dn_io_ptr = NULL; 201int fw_enable = 1; 202int fw_one_pass = 1; 203 204static 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 */ 210void 211ip_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 270void 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 */ 280void 281ip_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) { 381tooshort: 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#ifndef IPFIREWALL_FORWARD_EXTENDED 428 dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL); 429#else 430 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 431 /* 432 * Directly ship on the packet. This allows to forward packets 433 * that were destined for us to some other directly connected 434 * host. 435 */ 436 ip_forward(m, dchg); 437 return; 438 } 439#endif /* IPFIREWALL_FORWARD_EXTENDED */ 440#endif /* IPFIREWALL_FORWARD */ 441 442passin: 443 /* 444 * Process options and, if not destined for us, 445 * ship it on. ip_dooptions returns 1 when an 446 * error was detected (causing an icmp message 447 * to be sent and the original packet to be freed). 448 */ 449 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 450 return; 451 452 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 453 * matter if it is destined to another node, or whether it is 454 * a multicast one, RSVP wants it! and prevents it from being forwarded 455 * anywhere else. Also checks if the rsvp daemon is running before 456 * grabbing the packet. 457 */ 458 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 459 goto ours; 460 461 /* 462 * Check our list of addresses, to see if the packet is for us. 463 * If we don't have any addresses, assume any unicast packet 464 * we receive might be for us (and let the upper layers deal 465 * with it). 466 */ 467 if (TAILQ_EMPTY(&in_ifaddrhead) && 468 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 469 goto ours; 470 471 /* 472 * Enable a consistency check between the destination address 473 * and the arrival interface for a unicast packet (the RFC 1122 474 * strong ES model) if IP forwarding is disabled and the packet 475 * is not locally generated and the packet is not subject to 476 * 'ipfw fwd'. 477 * 478 * XXX - Checking also should be disabled if the destination 479 * address is ipnat'ed to a different interface. 480 * 481 * XXX - Checking is incompatible with IP aliases added 482 * to the loopback interface instead of the interface where 483 * the packets are received. 484 * 485 * XXX - This is the case for carp vhost IPs as well so we 486 * insert a workaround. If the packet got here, we already 487 * checked with carp_iamatch() and carp_forus(). 488 */ 489 checkif = ip_checkinterface && (ipforwarding == 0) && 490 m->m_pkthdr.rcvif != NULL && 491 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 492#ifdef DEV_CARP 493 !m->m_pkthdr.rcvif->if_carp && 494#endif 495 (dchg == 0); 496 497 /* 498 * Check for exact addresses in the hash bucket. 499 */ 500 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 501 /* 502 * If the address matches, verify that the packet 503 * arrived via the correct interface if checking is 504 * enabled. 505 */ 506 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 507 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 508 goto ours; 509 } 510 /* 511 * Check for broadcast addresses. 512 * 513 * Only accept broadcast packets that arrive via the matching 514 * interface. Reception of forwarded directed broadcasts would 515 * be handled via ip_forward() and ether_output() with the loopback 516 * into the stack for SIMPLEX interfaces handled by ether_output(). 517 */ 518 if (m->m_pkthdr.rcvif != NULL && 519 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 520 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 521 if (ifa->ifa_addr->sa_family != AF_INET) 522 continue; 523 ia = ifatoia(ifa); 524 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 525 ip->ip_dst.s_addr) 526 goto ours; 527 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 528 goto ours; 529#ifdef BOOTP_COMPAT 530 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 531 goto ours; 532#endif 533 } 534 } 535 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 536 struct in_multi *inm; 537 if (ip_mrouter) { 538 /* 539 * If we are acting as a multicast router, all 540 * incoming multicast packets are passed to the 541 * kernel-level multicast forwarding function. 542 * The packet is returned (relatively) intact; if 543 * ip_mforward() returns a non-zero value, the packet 544 * must be discarded, else it may be accepted below. 545 */ 546 if (ip_mforward && 547 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 548 ipstat.ips_cantforward++; 549 m_freem(m); 550 return; 551 } 552 553 /* 554 * The process-level routing daemon needs to receive 555 * all multicast IGMP packets, whether or not this 556 * host belongs to their destination groups. 557 */ 558 if (ip->ip_p == IPPROTO_IGMP) 559 goto ours; 560 ipstat.ips_forward++; 561 } 562 /* 563 * See if we belong to the destination multicast group on the 564 * arrival interface. 565 */ 566 IN_MULTI_LOCK(); 567 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 568 IN_MULTI_UNLOCK(); 569 if (inm == NULL) { 570 ipstat.ips_notmember++; 571 m_freem(m); 572 return; 573 } 574 goto ours; 575 } 576 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 577 goto ours; 578 if (ip->ip_dst.s_addr == INADDR_ANY) 579 goto ours; 580 581 /* 582 * FAITH(Firewall Aided Internet Translator) 583 */ 584 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 585 if (ip_keepfaith) { 586 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 587 goto ours; 588 } 589 m_freem(m); 590 return; 591 } 592 593 /* 594 * Not for us; forward if possible and desirable. 595 */ 596 if (ipforwarding == 0) { 597 ipstat.ips_cantforward++; 598 m_freem(m); 599 } else { 600#if defined(IPSEC) || defined(FAST_IPSEC) 601 if (ip_ipsec_fwd(m)) 602 goto bad; 603#endif /* IPSEC */ 604 ip_forward(m, dchg); 605 } 606 return; 607 608ours: 609#ifdef IPSTEALTH 610 /* 611 * IPSTEALTH: Process non-routing options only 612 * if the packet is destined for us. 613 */ 614 if (ipstealth && hlen > sizeof (struct ip) && 615 ip_dooptions(m, 1)) 616 return; 617#endif /* IPSTEALTH */ 618 619 /* Count the packet in the ip address stats */ 620 if (ia != NULL) { 621 ia->ia_ifa.if_ipackets++; 622 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 623 } 624 625 /* 626 * Attempt reassembly; if it succeeds, proceed. 627 * ip_reass() will return a different mbuf. 628 */ 629 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 630 m = ip_reass(m); 631 if (m == NULL) 632 return; 633 ip = mtod(m, struct ip *); 634 /* Get the header length of the reassembled packet */ 635 hlen = ip->ip_hl << 2; 636 } 637 638 /* 639 * Further protocols expect the packet length to be w/o the 640 * IP header. 641 */ 642 ip->ip_len -= hlen; 643 644#if defined(IPSEC) || defined(FAST_IPSEC) 645 /* 646 * enforce IPsec policy checking if we are seeing last header. 647 * note that we do not visit this with protocols with pcb layer 648 * code - like udp/tcp/raw ip. 649 */ 650 if (ip_ipsec_input(m)) 651 goto bad; 652#endif /* IPSEC */ 653 654 /* 655 * Switch out to protocol's input routine. 656 */ 657 ipstat.ips_delivered++; 658 659 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 660 return; 661bad: 662 m_freem(m); 663} 664 665/* 666 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 667 * max has slightly different semantics than the sysctl, for historical 668 * reasons. 669 */ 670static void 671maxnipq_update(void) 672{ 673 674 /* 675 * -1 for unlimited allocation. 676 */ 677 if (maxnipq < 0) 678 uma_zone_set_max(ipq_zone, 0); 679 /* 680 * Positive number for specific bound. 681 */ 682 if (maxnipq > 0) 683 uma_zone_set_max(ipq_zone, maxnipq); 684 /* 685 * Zero specifies no further fragment queue allocation -- set the 686 * bound very low, but rely on implementation elsewhere to actually 687 * prevent allocation and reclaim current queues. 688 */ 689 if (maxnipq == 0) 690 uma_zone_set_max(ipq_zone, 1); 691} 692
|
693static void 694ipq_zone_change(void *tag) 695{ 696 697 if (maxnipq > 0 && maxnipq < (nmbclusters / 32)) { 698 maxnipq = nmbclusters / 32; 699 maxnipq_update(); 700 } 701} 702 |
703static int 704sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 705{ 706 int error, i; 707 708 i = maxnipq; 709 error = sysctl_handle_int(oidp, &i, 0, req); 710 if (error || !req->newptr) 711 return (error); 712 713 /* 714 * XXXRW: Might be a good idea to sanity check the argument and place 715 * an extreme upper bound. 716 */ 717 if (i < -1) 718 return (EINVAL); 719 maxnipq = i; 720 maxnipq_update(); 721 return (0); 722} 723 724SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 725 NULL, 0, sysctl_maxnipq, "I", 726 "Maximum number of IPv4 fragment reassembly queue entries"); 727 728/* 729 * Take incoming datagram fragment and try to reassemble it into 730 * whole datagram. If the argument is the first fragment or one 731 * in between the function will return NULL and store the mbuf 732 * in the fragment chain. If the argument is the last fragment 733 * the packet will be reassembled and the pointer to the new 734 * mbuf returned for further processing. Only m_tags attached 735 * to the first packet/fragment are preserved. 736 * The IP header is *NOT* adjusted out of iplen. 737 */ 738 739struct mbuf * 740ip_reass(struct mbuf *m) 741{ 742 struct ip *ip; 743 struct mbuf *p, *q, *nq, *t; 744 struct ipq *fp = NULL; 745 struct ipqhead *head; 746 int i, hlen, next; 747 u_int8_t ecn, ecn0; 748 u_short hash; 749 750 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 751 if (maxnipq == 0 || maxfragsperpacket == 0) { 752 ipstat.ips_fragments++; 753 ipstat.ips_fragdropped++; 754 m_freem(m); 755 return (NULL); 756 } 757 758 ip = mtod(m, struct ip *); 759 hlen = ip->ip_hl << 2; 760 761 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 762 head = &ipq[hash]; 763 IPQ_LOCK(); 764 765 /* 766 * Look for queue of fragments 767 * of this datagram. 768 */ 769 TAILQ_FOREACH(fp, head, ipq_list) 770 if (ip->ip_id == fp->ipq_id && 771 ip->ip_src.s_addr == fp->ipq_src.s_addr && 772 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 773#ifdef MAC 774 mac_fragment_match(m, fp) && 775#endif 776 ip->ip_p == fp->ipq_p) 777 goto found; 778 779 fp = NULL; 780 781 /* 782 * Attempt to trim the number of allocated fragment queues if it 783 * exceeds the administrative limit. 784 */ 785 if ((nipq > maxnipq) && (maxnipq > 0)) { 786 /* 787 * drop something from the tail of the current queue 788 * before proceeding further 789 */ 790 struct ipq *q = TAILQ_LAST(head, ipqhead); 791 if (q == NULL) { /* gak */ 792 for (i = 0; i < IPREASS_NHASH; i++) { 793 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 794 if (r) { 795 ipstat.ips_fragtimeout += r->ipq_nfrags; 796 ip_freef(&ipq[i], r); 797 break; 798 } 799 } 800 } else { 801 ipstat.ips_fragtimeout += q->ipq_nfrags; 802 ip_freef(head, q); 803 } 804 } 805 806found: 807 /* 808 * Adjust ip_len to not reflect header, 809 * convert offset of this to bytes. 810 */ 811 ip->ip_len -= hlen; 812 if (ip->ip_off & IP_MF) { 813 /* 814 * Make sure that fragments have a data length 815 * that's a non-zero multiple of 8 bytes. 816 */ 817 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 818 ipstat.ips_toosmall++; /* XXX */ 819 goto dropfrag; 820 } 821 m->m_flags |= M_FRAG; 822 } else 823 m->m_flags &= ~M_FRAG; 824 ip->ip_off <<= 3; 825 826 827 /* 828 * Attempt reassembly; if it succeeds, proceed. 829 * ip_reass() will return a different mbuf. 830 */ 831 ipstat.ips_fragments++; 832 m->m_pkthdr.header = ip; 833 834 /* Previous ip_reass() started here. */ 835 /* 836 * Presence of header sizes in mbufs 837 * would confuse code below. 838 */ 839 m->m_data += hlen; 840 m->m_len -= hlen; 841 842 /* 843 * If first fragment to arrive, create a reassembly queue. 844 */ 845 if (fp == NULL) { 846 fp = uma_zalloc(ipq_zone, M_NOWAIT); 847 if (fp == NULL) 848 goto dropfrag; 849#ifdef MAC 850 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 851 uma_zfree(ipq_zone, fp); 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 1036dropfrag: 1037 ipstat.ips_fragdropped++; 1038 if (fp != NULL) 1039 fp->ipq_nfrags--; 1040 m_freem(m); 1041done: 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 */ 1052static void 1053ip_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 */ 1076void 1077ip_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 */ 1115void 1116ip_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 */ 1136int 1137ipproto_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 1171int 1172ipproto_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 */ 1196struct in_ifaddr * 1197ip_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 1219u_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 */ 1242void 1243ip_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 1434void 1435ip_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 { 1514makedummy: 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 */ 1535static int ip_rsvp_on; 1536struct socket *ip_rsvpd; 1537int 1538ip_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 1560int 1561ip_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 1575void 1576rsvp_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}
|