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sys/netinet/ip_input.c
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1 /* $NetBSD: ip_input.c,v 1.212.2.3 2007/09/17 20:14:21 bouyer Exp $ */ 2 3 /* 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /*- 33 * Copyright (c) 1998 The NetBSD Foundation, Inc. 34 * All rights reserved. 35 * 36 * This code is derived from software contributed to The NetBSD Foundation 37 * by Public Access Networks Corporation ("Panix"). It was developed under 38 * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon. 39 * 40 * Redistribution and use in source and binary forms, with or without 41 * modification, are permitted provided that the following conditions 42 * are met: 43 * 1. Redistributions of source code must retain the above copyright 44 * notice, this list of conditions and the following disclaimer. 45 * 2. Redistributions in binary form must reproduce the above copyright 46 * notice, this list of conditions and the following disclaimer in the 47 * documentation and/or other materials provided with the distribution. 48 * 3. All advertising materials mentioning features or use of this software 49 * must display the following acknowledgement: 50 * This product includes software developed by the NetBSD 51 * Foundation, Inc. and its contributors. 52 * 4. Neither the name of The NetBSD Foundation nor the names of its 53 * contributors may be used to endorse or promote products derived 54 * from this software without specific prior written permission. 55 * 56 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 57 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 58 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 59 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 60 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 61 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 62 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 63 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 64 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 65 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 66 * POSSIBILITY OF SUCH DAMAGE. 67 */ 68 69 /* 70 * Copyright (c) 1982, 1986, 1988, 1993 71 * The Regents of the University of California. All rights reserved. 72 * 73 * Redistribution and use in source and binary forms, with or without 74 * modification, are permitted provided that the following conditions 75 * are met: 76 * 1. Redistributions of source code must retain the above copyright 77 * notice, this list of conditions and the following disclaimer. 78 * 2. Redistributions in binary form must reproduce the above copyright 79 * notice, this list of conditions and the following disclaimer in the 80 * documentation and/or other materials provided with the distribution. 81 * 3. Neither the name of the University nor the names of its contributors 82 * may be used to endorse or promote products derived from this software 83 * without specific prior written permission. 84 * 85 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 86 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 87 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 88 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 89 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 90 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 91 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 92 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 93 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 94 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 95 * SUCH DAMAGE. 96 * 97 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 98 */ 99 100 #include <sys/cdefs.h> 101 __KERNEL_RCSID(0, "$NetBSD: ip_input.c,v 1.212.2.3 2007/09/17 20:14:21 bouyer Exp $"); 102 103 #include "opt_inet.h" 104 #include "opt_gateway.h" 105 #include "opt_pfil_hooks.h" 106 #include "opt_ipsec.h" 107 #include "opt_mrouting.h" 108 #include "opt_mbuftrace.h" 109 #include "opt_inet_csum.h" 110 111 #include <sys/param.h> 112 #include <sys/systm.h> 113 #include <sys/malloc.h> 114 #include <sys/mbuf.h> 115 #include <sys/domain.h> 116 #include <sys/protosw.h> 117 #include <sys/socket.h> 118 #include <sys/socketvar.h> 119 #include <sys/errno.h> 120 #include <sys/time.h> 121 #include <sys/kernel.h> 122 #include <sys/pool.h> 123 #include <sys/sysctl.h> 124 125 #include <net/if.h> 126 #include <net/if_dl.h> 127 #include <net/route.h> 128 #include <net/pfil.h> 129 130 #include <netinet/in.h> 131 #include <netinet/in_systm.h> 132 #include <netinet/ip.h> 133 #include <netinet/in_pcb.h> 134 #include <netinet/in_var.h> 135 #include <netinet/ip_var.h> 136 #include <netinet/ip_icmp.h> 137 /* just for gif_ttl */ 138 #include <netinet/in_gif.h> 139 #include "gif.h" 140 #include <net/if_gre.h> 141 #include "gre.h" 142 143 #ifdef MROUTING 144 #include <netinet/ip_mroute.h> 145 #endif 146 147 #ifdef IPSEC 148 #include <netinet6/ipsec.h> 149 #include <netkey/key.h> 150 #endif 151 #ifdef FAST_IPSEC 152 #include <netipsec/ipsec.h> 153 #include <netipsec/key.h> 154 #endif /* FAST_IPSEC*/ 155 156 #ifndef IPFORWARDING 157 #ifdef GATEWAY 158 #define IPFORWARDING 1 /* forward IP packets not for us */ 159 #else /* GATEWAY */ 160 #define IPFORWARDING 0 /* don't forward IP packets not for us */ 161 #endif /* GATEWAY */ 162 #endif /* IPFORWARDING */ 163 #ifndef IPSENDREDIRECTS 164 #define IPSENDREDIRECTS 1 165 #endif 166 #ifndef IPFORWSRCRT 167 #define IPFORWSRCRT 1 /* forward source-routed packets */ 168 #endif 169 #ifndef IPALLOWSRCRT 170 #define IPALLOWSRCRT 1 /* allow source-routed packets */ 171 #endif 172 #ifndef IPMTUDISC 173 #define IPMTUDISC 1 174 #endif 175 #ifndef IPMTUDISCTIMEOUT 176 #define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */ 177 #endif 178 179 /* 180 * Note: DIRECTED_BROADCAST is handled this way so that previous 181 * configuration using this option will Just Work. 182 */ 183 #ifndef IPDIRECTEDBCAST 184 #ifdef DIRECTED_BROADCAST 185 #define IPDIRECTEDBCAST 1 186 #else 187 #define IPDIRECTEDBCAST 0 188 #endif /* DIRECTED_BROADCAST */ 189 #endif /* IPDIRECTEDBCAST */ 190 int ipforwarding = IPFORWARDING; 191 int ipsendredirects = IPSENDREDIRECTS; 192 int ip_defttl = IPDEFTTL; 193 int ip_forwsrcrt = IPFORWSRCRT; 194 int ip_directedbcast = IPDIRECTEDBCAST; 195 int ip_allowsrcrt = IPALLOWSRCRT; 196 int ip_mtudisc = IPMTUDISC; 197 int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 198 #ifdef DIAGNOSTIC 199 int ipprintfs = 0; 200 #endif 201 202 int ip_do_randomid = 0; 203 204 /* 205 * XXX - Setting ip_checkinterface mostly implements the receive side of 206 * the Strong ES model described in RFC 1122, but since the routing table 207 * and transmit implementation do not implement the Strong ES model, 208 * setting this to 1 results in an odd hybrid. 209 * 210 * XXX - ip_checkinterface currently must be disabled if you use ipnat 211 * to translate the destination address to another local interface. 212 * 213 * XXX - ip_checkinterface must be disabled if you add IP aliases 214 * to the loopback interface instead of the interface where the 215 * packets for those addresses are received. 216 */ 217 int ip_checkinterface = 0; 218 219 220 struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 221 222 int ipqmaxlen = IFQ_MAXLEN; 223 u_long in_ifaddrhash; /* size of hash table - 1 */ 224 int in_ifaddrentries; /* total number of addrs */ 225 struct in_ifaddrhead in_ifaddrhead; 226 struct in_ifaddrhashhead *in_ifaddrhashtbl; 227 u_long in_multihash; /* size of hash table - 1 */ 228 int in_multientries; /* total number of addrs */ 229 struct in_multihashhead *in_multihashtbl; 230 struct ifqueue ipintrq; 231 struct ipstat ipstat; 232 uint16_t ip_id; 233 234 #ifdef PFIL_HOOKS 235 struct pfil_head inet_pfil_hook; 236 #endif 237 238 /* 239 * Cached copy of nmbclusters. If nbclusters is different, 240 * recalculate IP parameters derived from nmbclusters. 241 */ 242 static int ip_nmbclusters; /* copy of nmbclusters */ 243 static void ip_nmbclusters_changed(void); /* recalc limits */ 244 245 #define CHECK_NMBCLUSTER_PARAMS() \ 246 do { \ 247 if (__predict_false(ip_nmbclusters != nmbclusters)) \ 248 ip_nmbclusters_changed(); \ 249 } while (/*CONSTCOND*/0) 250 251 /* IP datagram reassembly queues (hashed) */ 252 #define IPREASS_NHASH_LOG2 6 253 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 254 #define IPREASS_HMASK (IPREASS_NHASH - 1) 255 #define IPREASS_HASH(x,y) \ 256 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 257 struct ipqhead ipq[IPREASS_NHASH]; 258 int ipq_locked; 259 static int ip_nfragpackets; /* packets in reass queue */ 260 static int ip_nfrags; /* total fragments in reass queues */ 261 262 int ip_maxfragpackets = 200; /* limit on packets. XXX sysctl */ 263 int ip_maxfrags; /* limit on fragments. XXX sysctl */ 264 265 266 /* 267 * Additive-Increase/Multiplicative-Decrease (AIMD) strategy for 268 * IP reassembly queue buffer managment. 269 * 270 * We keep a count of total IP fragments (NB: not fragmented packets!) 271 * awaiting reassembly (ip_nfrags) and a limit (ip_maxfrags) on fragments. 272 * If ip_nfrags exceeds ip_maxfrags the limit, we drop half the 273 * total fragments in reassembly queues.This AIMD policy avoids 274 * repeatedly deleting single packets under heavy fragmentation load 275 * (e.g., from lossy NFS peers). 276 */ 277 static u_int ip_reass_ttl_decr(u_int ticks); 278 static void ip_reass_drophalf(void); 279 280 281 static __inline int ipq_lock_try(void); 282 static __inline void ipq_unlock(void); 283 284 static __inline int 285 ipq_lock_try(void) 286 { 287 int s; 288 289 /* 290 * Use splvm() -- we're blocking things that would cause 291 * mbuf allocation. 292 */ 293 s = splvm(); 294 if (ipq_locked) { 295 splx(s); 296 return (0); 297 } 298 ipq_locked = 1; 299 splx(s); 300 return (1); 301 } 302 303 static __inline void 304 ipq_unlock(void) 305 { 306 int s; 307 308 s = splvm(); 309 ipq_locked = 0; 310 splx(s); 311 } 312 313 #ifdef DIAGNOSTIC 314 #define IPQ_LOCK() \ 315 do { \ 316 if (ipq_lock_try() == 0) { \ 317 printf("%s:%d: ipq already locked\n", __FILE__, __LINE__); \ 318 panic("ipq_lock"); \ 319 } \ 320 } while (/*CONSTCOND*/ 0) 321 #define IPQ_LOCK_CHECK() \ 322 do { \ 323 if (ipq_locked == 0) { \ 324 printf("%s:%d: ipq lock not held\n", __FILE__, __LINE__); \ 325 panic("ipq lock check"); \ 326 } \ 327 } while (/*CONSTCOND*/ 0) 328 #else 329 #define IPQ_LOCK() (void) ipq_lock_try() 330 #define IPQ_LOCK_CHECK() /* nothing */ 331 #endif 332 333 #define IPQ_UNLOCK() ipq_unlock() 334 335 POOL_INIT(inmulti_pool, sizeof(struct in_multi), 0, 0, 0, "inmltpl", NULL); 336 POOL_INIT(ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl", NULL); 337 338 #ifdef INET_CSUM_COUNTERS 339 #include <sys/device.h> 340 341 struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 342 NULL, "inet", "hwcsum bad"); 343 struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 344 NULL, "inet", "hwcsum ok"); 345 struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 346 NULL, "inet", "swcsum"); 347 348 #define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 349 350 EVCNT_ATTACH_STATIC(ip_hwcsum_bad); 351 EVCNT_ATTACH_STATIC(ip_hwcsum_ok); 352 EVCNT_ATTACH_STATIC(ip_swcsum); 353 354 #else 355 356 #define INET_CSUM_COUNTER_INCR(ev) /* nothing */ 357 358 #endif /* INET_CSUM_COUNTERS */ 359 360 /* 361 * We need to save the IP options in case a protocol wants to respond 362 * to an incoming packet over the same route if the packet got here 363 * using IP source routing. This allows connection establishment and 364 * maintenance when the remote end is on a network that is not known 365 * to us. 366 */ 367 int ip_nhops = 0; 368 static struct ip_srcrt { 369 struct in_addr dst; /* final destination */ 370 char nop; /* one NOP to align */ 371 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 372 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 373 } ip_srcrt; 374 375 static void save_rte(u_char *, struct in_addr); 376 377 #ifdef MBUFTRACE 378 struct mowner ip_rx_mowner = { "internet", "rx" }; 379 struct mowner ip_tx_mowner = { "internet", "tx" }; 380 #endif 381 382 /* 383 * Compute IP limits derived from the value of nmbclusters. 384 */ 385 static void 386 ip_nmbclusters_changed(void) 387 { 388 ip_maxfrags = nmbclusters / 4; 389 ip_nmbclusters = nmbclusters; 390 } 391 392 /* 393 * IP initialization: fill in IP protocol switch table. 394 * All protocols not implemented in kernel go to raw IP protocol handler. 395 */ 396 void 397 ip_init(void) 398 { 399 const struct protosw *pr; 400 int i; 401 402 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 403 if (pr == 0) 404 panic("ip_init"); 405 for (i = 0; i < IPPROTO_MAX; i++) 406 ip_protox[i] = pr - inetsw; 407 for (pr = inetdomain.dom_protosw; 408 pr < inetdomain.dom_protoswNPROTOSW; pr++) 409 if (pr->pr_domain->dom_family == PF_INET && 410 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 411 ip_protox[pr->pr_protocol] = pr - inetsw; 412 413 for (i = 0; i < IPREASS_NHASH; i++) 414 LIST_INIT(&ipq[i]); 415 416 ip_id = time.tv_sec & 0xfffff; 417 418 ipintrq.ifq_maxlen = ipqmaxlen; 419 ip_nmbclusters_changed(); 420 421 TAILQ_INIT(&in_ifaddrhead); 422 in_ifaddrhashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IFADDR, 423 M_WAITOK, &in_ifaddrhash); 424 in_multihashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IPMADDR, 425 M_WAITOK, &in_multihash); 426 ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout); 427 #ifdef GATEWAY 428 ipflow_init(); 429 #endif 430 431 #ifdef PFIL_HOOKS 432 /* Register our Packet Filter hook. */ 433 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 434 inet_pfil_hook.ph_af = AF_INET; 435 i = pfil_head_register(&inet_pfil_hook); 436 if (i != 0) 437 printf("ip_init: WARNING: unable to register pfil hook, " 438 "error %d\n", i); 439 #endif /* PFIL_HOOKS */ 440 441 #ifdef MBUFTRACE 442 MOWNER_ATTACH(&ip_tx_mowner); 443 MOWNER_ATTACH(&ip_rx_mowner); 444 #endif /* MBUFTRACE */ 445 } 446 447 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 448 struct route ipforward_rt; 449 450 /* 451 * IP software interrupt routine 452 */ 453 void 454 ipintr(void) 455 { 456 int s; 457 struct mbuf *m; 458 459 while (1) { 460 s = splnet(); 461 IF_DEQUEUE(&ipintrq, m); 462 splx(s); 463 if (m == 0) 464 return; 465 MCLAIM(m, &ip_rx_mowner); 466 ip_input(m); 467 } 468 } 469 470 /* 471 * Ip input routine. Checksum and byte swap header. If fragmented 472 * try to reassemble. Process options. Pass to next level. 473 */ 474 void 475 ip_input(struct mbuf *m) 476 { 477 struct ip *ip = NULL; 478 struct ipq *fp; 479 struct in_ifaddr *ia; 480 struct ifaddr *ifa; 481 struct ipqent *ipqe; 482 int hlen = 0, mff, len; 483 int downmatch; 484 int checkif; 485 int srcrt = 0; 486 u_int hash; 487 #ifdef FAST_IPSEC 488 struct m_tag *mtag; 489 struct tdb_ident *tdbi; 490 struct secpolicy *sp; 491 int s, error; 492 #endif /* FAST_IPSEC */ 493 494 MCLAIM(m, &ip_rx_mowner); 495 #ifdef DIAGNOSTIC 496 if ((m->m_flags & M_PKTHDR) == 0) 497 panic("ipintr no HDR"); 498 #endif 499 500 /* 501 * If no IP addresses have been set yet but the interfaces 502 * are receiving, can't do anything with incoming packets yet. 503 */ 504 if (TAILQ_FIRST(&in_ifaddrhead) == 0) 505 goto bad; 506 ipstat.ips_total++; 507 /* 508 * If the IP header is not aligned, slurp it up into a new 509 * mbuf with space for link headers, in the event we forward 510 * it. Otherwise, if it is aligned, make sure the entire 511 * base IP header is in the first mbuf of the chain. 512 */ 513 if (IP_HDR_ALIGNED_P(mtod(m, caddr_t)) == 0) { 514 if ((m = m_copyup(m, sizeof(struct ip), 515 (max_linkhdr + 3) & ~3)) == NULL) { 516 /* XXXJRT new stat, please */ 517 ipstat.ips_toosmall++; 518 return; 519 } 520 } else if (__predict_false(m->m_len < sizeof (struct ip))) { 521 if ((m = m_pullup(m, sizeof (struct ip))) == NULL) { 522 ipstat.ips_toosmall++; 523 return; 524 } 525 } 526 ip = mtod(m, struct ip *); 527 if (ip->ip_v != IPVERSION) { 528 ipstat.ips_badvers++; 529 goto bad; 530 } 531 hlen = ip->ip_hl << 2; 532 if (hlen < sizeof(struct ip)) { /* minimum header length */ 533 ipstat.ips_badhlen++; 534 goto bad; 535 } 536 if (hlen > m->m_len) { 537 if ((m = m_pullup(m, hlen)) == 0) { 538 ipstat.ips_badhlen++; 539 return; 540 } 541 ip = mtod(m, struct ip *); 542 } 543 544 /* 545 * RFC1122: packets with a multicast source address are 546 * not allowed. 547 */ 548 if (IN_MULTICAST(ip->ip_src.s_addr)) { 549 ipstat.ips_badaddr++; 550 goto bad; 551 } 552 553 /* 127/8 must not appear on wire - RFC1122 */ 554 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 555 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 556 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 557 ipstat.ips_badaddr++; 558 goto bad; 559 } 560 } 561 562 switch (m->m_pkthdr.csum_flags & 563 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_IPv4) | 564 M_CSUM_IPv4_BAD)) { 565 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 566 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad); 567 goto badcsum; 568 569 case M_CSUM_IPv4: 570 /* Checksum was okay. */ 571 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok); 572 break; 573 574 default: 575 /* 576 * Must compute it ourselves. Maybe skip checksum on 577 * loopback interfaces. 578 */ 579 if (__predict_true(!(m->m_pkthdr.rcvif->if_flags & 580 IFF_LOOPBACK) || ip_do_loopback_cksum)) { 581 INET_CSUM_COUNTER_INCR(&ip_swcsum); 582 if (in_cksum(m, hlen) != 0) 583 goto badcsum; 584 } 585 break; 586 } 587 588 /* Retrieve the packet length. */ 589 len = ntohs(ip->ip_len); 590 591 /* 592 * Check for additional length bogosity 593 */ 594 if (len < hlen) { 595 ipstat.ips_badlen++; 596 goto bad; 597 } 598 599 /* 600 * Check that the amount of data in the buffers 601 * is as at least much as the IP header would have us expect. 602 * Trim mbufs if longer than we expect. 603 * Drop packet if shorter than we expect. 604 */ 605 if (m->m_pkthdr.len < len) { 606 ipstat.ips_tooshort++; 607 goto bad; 608 } 609 if (m->m_pkthdr.len > len) { 610 if (m->m_len == m->m_pkthdr.len) { 611 m->m_len = len; 612 m->m_pkthdr.len = len; 613 } else 614 m_adj(m, len - m->m_pkthdr.len); 615 } 616 617 #if defined(IPSEC) 618 /* ipflow (IP fast forwarding) is not compatible with IPsec. */ 619 m->m_flags &= ~M_CANFASTFWD; 620 #else 621 /* 622 * Assume that we can create a fast-forward IP flow entry 623 * based on this packet. 624 */ 625 m->m_flags |= M_CANFASTFWD; 626 #endif 627 628 #ifdef PFIL_HOOKS 629 /* 630 * Run through list of hooks for input packets. If there are any 631 * filters which require that additional packets in the flow are 632 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 633 * Note that filters must _never_ set this flag, as another filter 634 * in the list may have previously cleared it. 635 */ 636 /* 637 * let ipfilter look at packet on the wire, 638 * not the decapsulated packet. 639 */ 640 #ifdef IPSEC 641 if (!ipsec_getnhist(m)) 642 #elif defined(FAST_IPSEC) 643 if (!ipsec_indone(m)) 644 #else 645 if (1) 646 #endif 647 { 648 struct in_addr odst; 649 650 odst = ip->ip_dst; 651 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 652 PFIL_IN) != 0) 653 return; 654 if (m == NULL) 655 return; 656 ip = mtod(m, struct ip *); 657 hlen = ip->ip_hl << 2; 658 /* 659 * XXX The setting of "srcrt" here is to prevent ip_forward() 660 * from generating ICMP redirects for packets that have 661 * been redirected by a hook back out on to the same LAN that 662 * they came from and is not an indication that the packet 663 * is being inffluenced by source routing options. This 664 * allows things like 665 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp" 666 * where tlp0 is both on the 1.1.1.0/24 network and is the 667 * default route for hosts on 1.1.1.0/24. Of course this 668 * also requires a "map tlp0 ..." to complete the story. 669 * One might argue whether or not this kind of network config. 670 * should be supported in this manner... 671 */ 672 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 673 } 674 #endif /* PFIL_HOOKS */ 675 676 #ifdef ALTQ 677 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 678 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 679 /* packet dropped by traffic conditioner */ 680 return; 681 } 682 #endif 683 684 /* 685 * Process options and, if not destined for us, 686 * ship it on. ip_dooptions returns 1 when an 687 * error was detected (causing an icmp message 688 * to be sent and the original packet to be freed). 689 */ 690 ip_nhops = 0; /* for source routed packets */ 691 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 692 return; 693 694 /* 695 * Enable a consistency check between the destination address 696 * and the arrival interface for a unicast packet (the RFC 1122 697 * strong ES model) if IP forwarding is disabled and the packet 698 * is not locally generated. 699 * 700 * XXX - Checking also should be disabled if the destination 701 * address is ipnat'ed to a different interface. 702 * 703 * XXX - Checking is incompatible with IP aliases added 704 * to the loopback interface instead of the interface where 705 * the packets are received. 706 * 707 * XXX - We need to add a per ifaddr flag for this so that 708 * we get finer grain control. 709 */ 710 checkif = ip_checkinterface && (ipforwarding == 0) && 711 (m->m_pkthdr.rcvif != NULL) && 712 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0); 713 714 /* 715 * Check our list of addresses, to see if the packet is for us. 716 * 717 * Traditional 4.4BSD did not consult IFF_UP at all. 718 * The behavior here is to treat addresses on !IFF_UP interface 719 * as not mine. 720 */ 721 downmatch = 0; 722 LIST_FOREACH(ia, &IN_IFADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 723 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) { 724 if (checkif && ia->ia_ifp != m->m_pkthdr.rcvif) 725 continue; 726 if ((ia->ia_ifp->if_flags & IFF_UP) != 0) 727 break; 728 else 729 downmatch++; 730 } 731 } 732 if (ia != NULL) 733 goto ours; 734 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 735 IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) { 736 if (ifa->ifa_addr->sa_family != AF_INET) 737 continue; 738 ia = ifatoia(ifa); 739 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 740 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 741 /* 742 * Look for all-0's host part (old broadcast addr), 743 * either for subnet or net. 744 */ 745 ip->ip_dst.s_addr == ia->ia_subnet || 746 ip->ip_dst.s_addr == ia->ia_net) 747 goto ours; 748 /* 749 * An interface with IP address zero accepts 750 * all packets that arrive on that interface. 751 */ 752 if (in_nullhost(ia->ia_addr.sin_addr)) 753 goto ours; 754 } 755 } 756 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 757 struct in_multi *inm; 758 #ifdef MROUTING 759 extern struct socket *ip_mrouter; 760 761 if (ip_mrouter) { 762 /* 763 * If we are acting as a multicast router, all 764 * incoming multicast packets are passed to the 765 * kernel-level multicast forwarding function. 766 * The packet is returned (relatively) intact; if 767 * ip_mforward() returns a non-zero value, the packet 768 * must be discarded, else it may be accepted below. 769 * 770 * (The IP ident field is put in the same byte order 771 * as expected when ip_mforward() is called from 772 * ip_output().) 773 */ 774 if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) { 775 ipstat.ips_cantforward++; 776 m_freem(m); 777 return; 778 } 779 780 /* 781 * The process-level routing demon needs to receive 782 * all multicast IGMP packets, whether or not this 783 * host belongs to their destination groups. 784 */ 785 if (ip->ip_p == IPPROTO_IGMP) 786 goto ours; 787 ipstat.ips_forward++; 788 } 789 #endif 790 /* 791 * See if we belong to the destination multicast group on the 792 * arrival interface. 793 */ 794 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 795 if (inm == NULL) { 796 ipstat.ips_cantforward++; 797 m_freem(m); 798 return; 799 } 800 goto ours; 801 } 802 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 803 in_nullhost(ip->ip_dst)) 804 goto ours; 805 806 /* 807 * Not for us; forward if possible and desirable. 808 */ 809 if (ipforwarding == 0) { 810 ipstat.ips_cantforward++; 811 m_freem(m); 812 } else { 813 /* 814 * If ip_dst matched any of my address on !IFF_UP interface, 815 * and there's no IFF_UP interface that matches ip_dst, 816 * send icmp unreach. Forwarding it will result in in-kernel 817 * forwarding loop till TTL goes to 0. 818 */ 819 if (downmatch) { 820 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 821 ipstat.ips_cantforward++; 822 return; 823 } 824 #ifdef IPSEC 825 if (ipsec4_in_reject(m, NULL)) { 826 ipsecstat.in_polvio++; 827 goto bad; 828 } 829 #endif 830 #ifdef FAST_IPSEC 831 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 832 s = splsoftnet(); 833 if (mtag != NULL) { 834 tdbi = (struct tdb_ident *)(mtag + 1); 835 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 836 } else { 837 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 838 IP_FORWARDING, &error); 839 } 840 if (sp == NULL) { /* NB: can happen if error */ 841 splx(s); 842 /*XXX error stat???*/ 843 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 844 goto bad; 845 } 846 847 /* 848 * Check security policy against packet attributes. 849 */ 850 error = ipsec_in_reject(sp, m); 851 KEY_FREESP(&sp); 852 splx(s); 853 if (error) { 854 ipstat.ips_cantforward++; 855 goto bad; 856 } 857 858 /* 859 * Peek at the outbound SP for this packet to determine if 860 * it's a Fast Forward candidate. 861 */ 862 mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 863 if (mtag != NULL) 864 m->m_flags &= ~M_CANFASTFWD; 865 else { 866 s = splsoftnet(); 867 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, 868 (IP_FORWARDING | 869 (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 870 &error, NULL); 871 if (sp != NULL) { 872 m->m_flags &= ~M_CANFASTFWD; 873 KEY_FREESP(&sp); 874 } 875 splx(s); 876 } 877 #endif /* FAST_IPSEC */ 878 879 ip_forward(m, srcrt); 880 } 881 return; 882 883 ours: 884 /* 885 * If offset or IP_MF are set, must reassemble. 886 * Otherwise, nothing need be done. 887 * (We could look in the reassembly queue to see 888 * if the packet was previously fragmented, 889 * but it's not worth the time; just let them time out.) 890 */ 891 if (ip->ip_off & ~htons(IP_DF|IP_RF)) { 892 893 /* 894 * Look for queue of fragments 895 * of this datagram. 896 */ 897 IPQ_LOCK(); 898 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 899 /* XXX LIST_FOREACH(fp, &ipq[hash], ipq_q) */ 900 for (fp = LIST_FIRST(&ipq[hash]); fp != NULL; 901 fp = LIST_NEXT(fp, ipq_q)) { 902 if (ip->ip_id == fp->ipq_id && 903 in_hosteq(ip->ip_src, fp->ipq_src) && 904 in_hosteq(ip->ip_dst, fp->ipq_dst) && 905 ip->ip_p == fp->ipq_p) 906 goto found; 907 908 } 909 fp = 0; 910 found: 911 912 /* 913 * Adjust ip_len to not reflect header, 914 * set ipqe_mff if more fragments are expected, 915 * convert offset of this to bytes. 916 */ 917 ip->ip_len = htons(ntohs(ip->ip_len) - hlen); 918 mff = (ip->ip_off & htons(IP_MF)) != 0; 919 if (mff) { 920 /* 921 * Make sure that fragments have a data length 922 * that's a non-zero multiple of 8 bytes. 923 */ 924 if (ntohs(ip->ip_len) == 0 || 925 (ntohs(ip->ip_len) & 0x7) != 0) { 926 ipstat.ips_badfrags++; 927 IPQ_UNLOCK(); 928 goto bad; 929 } 930 } 931 ip->ip_off = htons((ntohs(ip->ip_off) & IP_OFFMASK) << 3); 932 933 /* 934 * If datagram marked as having more fragments 935 * or if this is not the first fragment, 936 * attempt reassembly; if it succeeds, proceed. 937 */ 938 if (mff || ip->ip_off != htons(0)) { 939 ipstat.ips_fragments++; 940 ipqe = pool_get(&ipqent_pool, PR_NOWAIT); 941 if (ipqe == NULL) { 942 ipstat.ips_rcvmemdrop++; 943 IPQ_UNLOCK(); 944 goto bad; 945 } 946 ipqe->ipqe_mff = mff; 947 ipqe->ipqe_m = m; 948 ipqe->ipqe_ip = ip; 949 m = ip_reass(ipqe, fp, &ipq[hash]); 950 if (m == 0) { 951 IPQ_UNLOCK(); 952 return; 953 } 954 ipstat.ips_reassembled++; 955 ip = mtod(m, struct ip *); 956 hlen = ip->ip_hl << 2; 957 ip->ip_len = htons(ntohs(ip->ip_len) + hlen); 958 } else 959 if (fp) 960 ip_freef(fp); 961 IPQ_UNLOCK(); 962 } 963 964 #if defined(IPSEC) 965 /* 966 * enforce IPsec policy checking if we are seeing last header. 967 * note that we do not visit this with protocols with pcb layer 968 * code - like udp/tcp/raw ip. 969 */ 970 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 971 ipsec4_in_reject(m, NULL)) { 972 ipsecstat.in_polvio++; 973 goto bad; 974 } 975 #endif 976 #if FAST_IPSEC 977 /* 978 * enforce IPsec policy checking if we are seeing last header. 979 * note that we do not visit this with protocols with pcb layer 980 * code - like udp/tcp/raw ip. 981 */ 982 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 983 /* 984 * Check if the packet has already had IPsec processing 985 * done. If so, then just pass it along. This tag gets 986 * set during AH, ESP, etc. input handling, before the 987 * packet is returned to the ip input queue for delivery. 988 */ 989 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 990 s = splsoftnet(); 991 if (mtag != NULL) { 992 tdbi = (struct tdb_ident *)(mtag + 1); 993 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 994 } else { 995 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 996 IP_FORWARDING, &error); 997 } 998 if (sp != NULL) { 999 /* 1000 * Check security policy against packet attributes. 1001 */ 1002 error = ipsec_in_reject(sp, m); 1003 KEY_FREESP(&sp); 1004 } else { 1005 /* XXX error stat??? */ 1006 error = EINVAL; 1007 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 1008 } 1009 splx(s); 1010 if (error) 1011 goto bad; 1012 } 1013 #endif /* FAST_IPSEC */ 1014 1015 /* 1016 * Switch out to protocol's input routine. 1017 */ 1018 #if IFA_STATS 1019 if (ia && ip) 1020 ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len); 1021 #endif 1022 ipstat.ips_delivered++; 1023 { 1024 int off = hlen, nh = ip->ip_p; 1025 1026 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 1027 return; 1028 } 1029 bad: 1030 m_freem(m); 1031 return; 1032 1033 badcsum: 1034 ipstat.ips_badsum++; 1035 m_freem(m); 1036 } 1037 1038 /* 1039 * Take incoming datagram fragment and try to 1040 * reassemble it into whole datagram. If a chain for 1041 * reassembly of this datagram already exists, then it 1042 * is given as fp; otherwise have to make a chain. 1043 */ 1044 struct mbuf * 1045 ip_reass(struct ipqent *ipqe, struct ipq *fp, struct ipqhead *ipqhead) 1046 { 1047 struct mbuf *m = ipqe->ipqe_m; 1048 struct ipqent *nq, *p, *q; 1049 struct ip *ip; 1050 struct mbuf *t; 1051 int hlen = ipqe->ipqe_ip->ip_hl << 2; 1052 int i, next; 1053 1054 IPQ_LOCK_CHECK(); 1055 1056 /* 1057 * Presence of header sizes in mbufs 1058 * would confuse code below. 1059 */ 1060 m->m_data += hlen; 1061 m->m_len -= hlen; 1062 1063 #ifdef notyet 1064 /* make sure fragment limit is up-to-date */ 1065 CHECK_NMBCLUSTER_PARAMS(); 1066 1067 /* If we have too many fragments, drop the older half. */ 1068 if (ip_nfrags >= ip_maxfrags) 1069 ip_reass_drophalf(void); 1070 #endif 1071 1072 /* 1073 * We are about to add a fragment; increment frag count. 1074 */ 1075 ip_nfrags++; 1076 1077 /* 1078 * If first fragment to arrive, create a reassembly queue. 1079 */ 1080 if (fp == 0) { 1081 /* 1082 * Enforce upper bound on number of fragmented packets 1083 * for which we attempt reassembly; 1084 * If maxfrag is 0, never accept fragments. 1085 * If maxfrag is -1, accept all fragments without limitation. 1086 */ 1087 if (ip_maxfragpackets < 0) 1088 ; 1089 else if (ip_nfragpackets >= ip_maxfragpackets) 1090 goto dropfrag; 1091 ip_nfragpackets++; 1092 MALLOC(fp, struct ipq *, sizeof (struct ipq), 1093 M_FTABLE, M_NOWAIT); 1094 if (fp == NULL) 1095 goto dropfrag; 1096 LIST_INSERT_HEAD(ipqhead, fp, ipq_q); 1097 fp->ipq_nfrags = 1; 1098 fp->ipq_ttl = IPFRAGTTL; 1099 fp->ipq_p = ipqe->ipqe_ip->ip_p; 1100 fp->ipq_id = ipqe->ipqe_ip->ip_id; 1101 TAILQ_INIT(&fp->ipq_fragq); 1102 fp->ipq_src = ipqe->ipqe_ip->ip_src; 1103 fp->ipq_dst = ipqe->ipqe_ip->ip_dst; 1104 p = NULL; 1105 goto insert; 1106 } else { 1107 fp->ipq_nfrags++; 1108 } 1109 1110 /* 1111 * Find a segment which begins after this one does. 1112 */ 1113 for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; 1114 p = q, q = TAILQ_NEXT(q, ipqe_q)) 1115 if (ntohs(q->ipqe_ip->ip_off) > ntohs(ipqe->ipqe_ip->ip_off)) 1116 break; 1117 1118 /* 1119 * If there is a preceding segment, it may provide some of 1120 * our data already. If so, drop the data from the incoming 1121 * segment. If it provides all of our data, drop us. 1122 */ 1123 if (p != NULL) { 1124 i = ntohs(p->ipqe_ip->ip_off) + ntohs(p->ipqe_ip->ip_len) - 1125 ntohs(ipqe->ipqe_ip->ip_off); 1126 if (i > 0) { 1127 if (i >= ntohs(ipqe->ipqe_ip->ip_len)) 1128 goto dropfrag; 1129 m_adj(ipqe->ipqe_m, i); 1130 ipqe->ipqe_ip->ip_off = 1131 htons(ntohs(ipqe->ipqe_ip->ip_off) + i); 1132 ipqe->ipqe_ip->ip_len = 1133 htons(ntohs(ipqe->ipqe_ip->ip_len) - i); 1134 } 1135 } 1136 1137 /* 1138 * While we overlap succeeding segments trim them or, 1139 * if they are completely covered, dequeue them. 1140 */ 1141 for (; q != NULL && 1142 ntohs(ipqe->ipqe_ip->ip_off) + ntohs(ipqe->ipqe_ip->ip_len) > 1143 ntohs(q->ipqe_ip->ip_off); q = nq) { 1144 i = (ntohs(ipqe->ipqe_ip->ip_off) + 1145 ntohs(ipqe->ipqe_ip->ip_len)) - ntohs(q->ipqe_ip->ip_off); 1146 if (i < ntohs(q->ipqe_ip->ip_len)) { 1147 q->ipqe_ip->ip_len = 1148 htons(ntohs(q->ipqe_ip->ip_len) - i); 1149 q->ipqe_ip->ip_off = 1150 htons(ntohs(q->ipqe_ip->ip_off) + i); 1151 m_adj(q->ipqe_m, i); 1152 break; 1153 } 1154 nq = TAILQ_NEXT(q, ipqe_q); 1155 m_freem(q->ipqe_m); 1156 TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q); 1157 pool_put(&ipqent_pool, q); 1158 fp->ipq_nfrags--; 1159 ip_nfrags--; 1160 } 1161 1162 insert: 1163 /* 1164 * Stick new segment in its place; 1165 * check for complete reassembly. 1166 */ 1167 if (p == NULL) { 1168 TAILQ_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); 1169 } else { 1170 TAILQ_INSERT_AFTER(&fp->ipq_fragq, p, ipqe, ipqe_q); 1171 } 1172 next = 0; 1173 for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; 1174 p = q, q = TAILQ_NEXT(q, ipqe_q)) { 1175 if (ntohs(q->ipqe_ip->ip_off) != next) 1176 return (0); 1177 next += ntohs(q->ipqe_ip->ip_len); 1178 } 1179 if (p->ipqe_mff) 1180 return (0); 1181 1182 /* 1183 * Reassembly is complete. Check for a bogus message size and 1184 * concatenate fragments. 1185 */ 1186 q = TAILQ_FIRST(&fp->ipq_fragq); 1187 ip = q->ipqe_ip; 1188 if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) { 1189 ipstat.ips_toolong++; 1190 ip_freef(fp); 1191 return (0); 1192 } 1193 m = q->ipqe_m; 1194 t = m->m_next; 1195 m->m_next = 0; 1196 m_cat(m, t); 1197 nq = TAILQ_NEXT(q, ipqe_q); 1198 pool_put(&ipqent_pool, q); 1199 for (q = nq; q != NULL; q = nq) { 1200 t = q->ipqe_m; 1201 nq = TAILQ_NEXT(q, ipqe_q); 1202 pool_put(&ipqent_pool, q); 1203 m_cat(m, t); 1204 } 1205 ip_nfrags -= fp->ipq_nfrags; 1206 1207 /* 1208 * Create header for new ip packet by 1209 * modifying header of first packet; 1210 * dequeue and discard fragment reassembly header. 1211 * Make header visible. 1212 */ 1213 ip->ip_len = htons(next); 1214 ip->ip_src = fp->ipq_src; 1215 ip->ip_dst = fp->ipq_dst; 1216 LIST_REMOVE(fp, ipq_q); 1217 FREE(fp, M_FTABLE); 1218 ip_nfragpackets--; 1219 m->m_len += (ip->ip_hl << 2); 1220 m->m_data -= (ip->ip_hl << 2); 1221 /* some debugging cruft by sklower, below, will go away soon */ 1222 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1223 int plen = 0; 1224 for (t = m; t; t = t->m_next) 1225 plen += t->m_len; 1226 m->m_pkthdr.len = plen; 1227 m->m_pkthdr.csum_flags = 0; 1228 } 1229 return (m); 1230 1231 dropfrag: 1232 if (fp != 0) 1233 fp->ipq_nfrags--; 1234 ip_nfrags--; 1235 ipstat.ips_fragdropped++; 1236 m_freem(m); 1237 pool_put(&ipqent_pool, ipqe); 1238 return (0); 1239 } 1240 1241 /* 1242 * Free a fragment reassembly header and all 1243 * associated datagrams. 1244 */ 1245 void 1246 ip_freef(struct ipq *fp) 1247 { 1248 struct ipqent *q, *p; 1249 u_int nfrags = 0; 1250 1251 IPQ_LOCK_CHECK(); 1252 1253 for (q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; q = p) { 1254 p = TAILQ_NEXT(q, ipqe_q); 1255 m_freem(q->ipqe_m); 1256 nfrags++; 1257 TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q); 1258 pool_put(&ipqent_pool, q); 1259 } 1260 1261 if (nfrags != fp->ipq_nfrags) 1262 printf("ip_freef: nfrags %d != %d\n", fp->ipq_nfrags, nfrags); 1263 ip_nfrags -= nfrags; 1264 LIST_REMOVE(fp, ipq_q); 1265 FREE(fp, M_FTABLE); 1266 ip_nfragpackets--; 1267 } 1268 1269 /* 1270 * IP reassembly TTL machinery for multiplicative drop. 1271 */ 1272 static u_int fragttl_histo[(IPFRAGTTL+1)]; 1273 1274 1275 /* 1276 * Decrement TTL of all reasembly queue entries by `ticks'. 1277 * Count number of distinct fragments (as opposed to partial, fragmented 1278 * datagrams) in the reassembly queue. While we traverse the entire 1279 * reassembly queue, compute and return the median TTL over all fragments. 1280 */ 1281 static u_int 1282 ip_reass_ttl_decr(u_int ticks) 1283 { 1284 u_int nfrags, median, dropfraction, keepfraction; 1285 struct ipq *fp, *nfp; 1286 int i; 1287 1288 nfrags = 0; 1289 memset(fragttl_histo, 0, sizeof fragttl_histo); 1290 1291 for (i = 0; i < IPREASS_NHASH; i++) { 1292 for (fp = LIST_FIRST(&ipq[i]); fp != NULL; fp = nfp) { 1293 fp->ipq_ttl = ((fp->ipq_ttl <= ticks) ? 1294 0 : fp->ipq_ttl - ticks); 1295 nfp = LIST_NEXT(fp, ipq_q); 1296 if (fp->ipq_ttl == 0) { 1297 ipstat.ips_fragtimeout++; 1298 ip_freef(fp); 1299 } else { 1300 nfrags += fp->ipq_nfrags; 1301 fragttl_histo[fp->ipq_ttl] += fp->ipq_nfrags; 1302 } 1303 } 1304 } 1305 1306 KASSERT(ip_nfrags == nfrags); 1307 1308 /* Find median (or other drop fraction) in histogram. */ 1309 dropfraction = (ip_nfrags / 2); 1310 keepfraction = ip_nfrags - dropfraction; 1311 for (i = IPFRAGTTL, median = 0; i >= 0; i--) { 1312 median += fragttl_histo[i]; 1313 if (median >= keepfraction) 1314 break; 1315 } 1316 1317 /* Return TTL of median (or other fraction). */ 1318 return (u_int)i; 1319 } 1320 1321 void 1322 ip_reass_drophalf(void) 1323 { 1324 1325 u_int median_ticks; 1326 /* 1327 * Compute median TTL of all fragments, and count frags 1328 * with that TTL or lower (roughly half of all fragments). 1329 */ 1330 median_ticks = ip_reass_ttl_decr(0); 1331 1332 /* Drop half. */ 1333 median_ticks = ip_reass_ttl_decr(median_ticks); 1334 1335 } 1336 1337 /* 1338 * IP timer processing; 1339 * if a timer expires on a reassembly 1340 * queue, discard it. 1341 */ 1342 void 1343 ip_slowtimo(void) 1344 { 1345 static u_int dropscanidx = 0; 1346 u_int i; 1347 u_int median_ttl; 1348 int s = splsoftnet(); 1349 1350 IPQ_LOCK(); 1351 1352 /* Age TTL of all fragments by 1 tick .*/ 1353 median_ttl = ip_reass_ttl_decr(1); 1354 1355 /* make sure fragment limit is up-to-date */ 1356 CHECK_NMBCLUSTER_PARAMS(); 1357 1358 /* If we have too many fragments, drop the older half. */ 1359 if (ip_nfrags > ip_maxfrags) 1360 ip_reass_ttl_decr(median_ttl); 1361 1362 /* 1363 * If we are over the maximum number of fragmented packets 1364 * (due to the limit being lowered), drain off 1365 * enough to get down to the new limit. Start draining 1366 * from the reassembly hashqueue most recently drained. 1367 */ 1368 if (ip_maxfragpackets < 0) 1369 ; 1370 else { 1371 int wrapped = 0; 1372 1373 i = dropscanidx; 1374 while (ip_nfragpackets > ip_maxfragpackets && wrapped == 0) { 1375 while (LIST_FIRST(&ipq[i]) != NULL) 1376 ip_freef(LIST_FIRST(&ipq[i])); 1377 if (++i >= IPREASS_NHASH) { 1378 i = 0; 1379 } 1380 /* 1381 * Dont scan forever even if fragment counters are 1382 * wrong: stop after scanning entire reassembly queue. 1383 */ 1384 if (i == dropscanidx) 1385 wrapped = 1; 1386 } 1387 dropscanidx = i; 1388 } 1389 IPQ_UNLOCK(); 1390 #ifdef GATEWAY 1391 ipflow_slowtimo(); 1392 #endif 1393 splx(s); 1394 } 1395 1396 /* 1397 * Drain off all datagram fragments. 1398 */ 1399 void 1400 ip_drain(void) 1401 { 1402 1403 /* 1404 * We may be called from a device's interrupt context. If 1405 * the ipq is already busy, just bail out now. 1406 */ 1407 if (ipq_lock_try() == 0) 1408 return; 1409 1410 /* 1411 * Drop half the total fragments now. If more mbufs are needed, 1412 * we will be called again soon. 1413 */ 1414 ip_reass_drophalf(); 1415 1416 IPQ_UNLOCK(); 1417 } 1418 1419 /* 1420 * Do option processing on a datagram, 1421 * possibly discarding it if bad options are encountered, 1422 * or forwarding it if source-routed. 1423 * Returns 1 if packet has been forwarded/freed, 1424 * 0 if the packet should be processed further. 1425 */ 1426 int 1427 ip_dooptions(struct mbuf *m) 1428 { 1429 struct ip *ip = mtod(m, struct ip *); 1430 u_char *cp, *cp0; 1431 struct ip_timestamp *ipt; 1432 struct in_ifaddr *ia; 1433 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1434 struct in_addr dst; 1435 n_time ntime; 1436 1437 dst = ip->ip_dst; 1438 cp = (u_char *)(ip + 1); 1439 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1440 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1441 opt = cp[IPOPT_OPTVAL]; 1442 if (opt == IPOPT_EOL) 1443 break; 1444 if (opt == IPOPT_NOP) 1445 optlen = 1; 1446 else { 1447 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1448 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1449 goto bad; 1450 } 1451 optlen = cp[IPOPT_OLEN]; 1452 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1453 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1454 goto bad; 1455 } 1456 } 1457 switch (opt) { 1458 1459 default: 1460 break; 1461 1462 /* 1463 * Source routing with record. 1464 * Find interface with current destination address. 1465 * If none on this machine then drop if strictly routed, 1466 * or do nothing if loosely routed. 1467 * Record interface address and bring up next address 1468 * component. If strictly routed make sure next 1469 * address is on directly accessible net. 1470 */ 1471 case IPOPT_LSRR: 1472 case IPOPT_SSRR: 1473 if (ip_allowsrcrt == 0) { 1474 type = ICMP_UNREACH; 1475 code = ICMP_UNREACH_NET_PROHIB; 1476 goto bad; 1477 } 1478 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1479 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1480 goto bad; 1481 } 1482 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1483 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1484 goto bad; 1485 } 1486 ipaddr.sin_addr = ip->ip_dst; 1487 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); 1488 if (ia == 0) { 1489 if (opt == IPOPT_SSRR) { 1490 type = ICMP_UNREACH; 1491 code = ICMP_UNREACH_SRCFAIL; 1492 goto bad; 1493 } 1494 /* 1495 * Loose routing, and not at next destination 1496 * yet; nothing to do except forward. 1497 */ 1498 break; 1499 } 1500 off--; /* 0 origin */ 1501 if ((off + sizeof(struct in_addr)) > optlen) { 1502 /* 1503 * End of source route. Should be for us. 1504 */ 1505 save_rte(cp, ip->ip_src); 1506 break; 1507 } 1508 /* 1509 * locate outgoing interface 1510 */ 1511 bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr, 1512 sizeof(ipaddr.sin_addr)); 1513 if (opt == IPOPT_SSRR) 1514 ia = ifatoia(ifa_ifwithladdr(sintosa(&ipaddr))); 1515 else 1516 ia = ip_rtaddr(ipaddr.sin_addr); 1517 if (ia == 0) { 1518 type = ICMP_UNREACH; 1519 code = ICMP_UNREACH_SRCFAIL; 1520 goto bad; 1521 } 1522 ip->ip_dst = ipaddr.sin_addr; 1523 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1524 (caddr_t)(cp + off), sizeof(struct in_addr)); 1525 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1526 /* 1527 * Let ip_intr's mcast routing check handle mcast pkts 1528 */ 1529 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1530 break; 1531 1532 case IPOPT_RR: 1533 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1534 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1535 goto bad; 1536 } 1537 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1538 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1539 goto bad; 1540 } 1541 /* 1542 * If no space remains, ignore. 1543 */ 1544 off--; /* 0 origin */ 1545 if ((off + sizeof(struct in_addr)) > optlen) 1546 break; 1547 bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr, 1548 sizeof(ipaddr.sin_addr)); 1549 /* 1550 * locate outgoing interface; if we're the destination, 1551 * use the incoming interface (should be same). 1552 */ 1553 if ((ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)))) 1554 == NULL && 1555 (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) { 1556 type = ICMP_UNREACH; 1557 code = ICMP_UNREACH_HOST; 1558 goto bad; 1559 } 1560 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1561 (caddr_t)(cp + off), sizeof(struct in_addr)); 1562 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1563 break; 1564 1565 case IPOPT_TS: 1566 code = cp - (u_char *)ip; 1567 ipt = (struct ip_timestamp *)cp; 1568 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1569 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1570 goto bad; 1571 } 1572 if (ipt->ipt_ptr < 5) { 1573 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1574 goto bad; 1575 } 1576 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) { 1577 if (++ipt->ipt_oflw == 0) { 1578 code = (u_char *)&ipt->ipt_ptr - 1579 (u_char *)ip; 1580 goto bad; 1581 } 1582 break; 1583 } 1584 cp0 = (cp + ipt->ipt_ptr - 1); 1585 switch (ipt->ipt_flg) { 1586 1587 case IPOPT_TS_TSONLY: 1588 break; 1589 1590 case IPOPT_TS_TSANDADDR: 1591 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1592 sizeof(struct in_addr) > ipt->ipt_len) { 1593 code = (u_char *)&ipt->ipt_ptr - 1594 (u_char *)ip; 1595 goto bad; 1596 } 1597 ipaddr.sin_addr = dst; 1598 ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr), 1599 m->m_pkthdr.rcvif)); 1600 if (ia == 0) 1601 continue; 1602 bcopy(&ia->ia_addr.sin_addr, 1603 cp0, sizeof(struct in_addr)); 1604 ipt->ipt_ptr += sizeof(struct in_addr); 1605 break; 1606 1607 case IPOPT_TS_PRESPEC: 1608 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1609 sizeof(struct in_addr) > ipt->ipt_len) { 1610 code = (u_char *)&ipt->ipt_ptr - 1611 (u_char *)ip; 1612 goto bad; 1613 } 1614 bcopy(cp0, &ipaddr.sin_addr, 1615 sizeof(struct in_addr)); 1616 if (ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))) 1617 == NULL) 1618 continue; 1619 ipt->ipt_ptr += sizeof(struct in_addr); 1620 break; 1621 1622 default: 1623 /* XXX can't take &ipt->ipt_flg */ 1624 code = (u_char *)&ipt->ipt_ptr - 1625 (u_char *)ip + 1; 1626 goto bad; 1627 } 1628 ntime = iptime(); 1629 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1630 bcopy(cp0, (caddr_t)cp + ipt->ipt_ptr - 1, 1631 sizeof(n_time)); 1632 ipt->ipt_ptr += sizeof(n_time); 1633 } 1634 } 1635 if (forward) { 1636 if (ip_forwsrcrt == 0) { 1637 type = ICMP_UNREACH; 1638 code = ICMP_UNREACH_SRCFAIL; 1639 goto bad; 1640 } 1641 ip_forward(m, 1); 1642 return (1); 1643 } 1644 return (0); 1645 bad: 1646 icmp_error(m, type, code, 0, 0); 1647 ipstat.ips_badoptions++; 1648 return (1); 1649 } 1650 1651 /* 1652 * Given address of next destination (final or next hop), 1653 * return internet address info of interface to be used to get there. 1654 */ 1655 struct in_ifaddr * 1656 ip_rtaddr(struct in_addr dst) 1657 { 1658 struct sockaddr_in *sin; 1659 1660 sin = satosin(&ipforward_rt.ro_dst); 1661 1662 if (ipforward_rt.ro_rt == 0 || !in_hosteq(dst, sin->sin_addr)) { 1663 if (ipforward_rt.ro_rt) { 1664 RTFREE(ipforward_rt.ro_rt); 1665 ipforward_rt.ro_rt = 0; 1666 } 1667 sin->sin_family = AF_INET; 1668 sin->sin_len = sizeof(*sin); 1669 sin->sin_addr = dst; 1670 1671 rtalloc(&ipforward_rt); 1672 } 1673 if (ipforward_rt.ro_rt == 0) 1674 return ((struct in_ifaddr *)0); 1675 return (ifatoia(ipforward_rt.ro_rt->rt_ifa)); 1676 } 1677 1678 /* 1679 * Save incoming source route for use in replies, 1680 * to be picked up later by ip_srcroute if the receiver is interested. 1681 */ 1682 void 1683 save_rte(u_char *option, struct in_addr dst) 1684 { 1685 unsigned olen; 1686 1687 olen = option[IPOPT_OLEN]; 1688 #ifdef DIAGNOSTIC 1689 if (ipprintfs) 1690 printf("save_rte: olen %d\n", olen); 1691 #endif /* 0 */ 1692 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1693 return; 1694 bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen); 1695 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1696 ip_srcrt.dst = dst; 1697 } 1698 1699 /* 1700 * Retrieve incoming source route for use in replies, 1701 * in the same form used by setsockopt. 1702 * The first hop is placed before the options, will be removed later. 1703 */ 1704 struct mbuf * 1705 ip_srcroute(void) 1706 { 1707 struct in_addr *p, *q; 1708 struct mbuf *m; 1709 1710 if (ip_nhops == 0) 1711 return ((struct mbuf *)0); 1712 m = m_get(M_DONTWAIT, MT_SOOPTS); 1713 if (m == 0) 1714 return ((struct mbuf *)0); 1715 1716 MCLAIM(m, &inetdomain.dom_mowner); 1717 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1718 1719 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1720 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1721 OPTSIZ; 1722 #ifdef DIAGNOSTIC 1723 if (ipprintfs) 1724 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1725 #endif 1726 1727 /* 1728 * First save first hop for return route 1729 */ 1730 p = &ip_srcrt.route[ip_nhops - 1]; 1731 *(mtod(m, struct in_addr *)) = *p--; 1732 #ifdef DIAGNOSTIC 1733 if (ipprintfs) 1734 printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1735 #endif 1736 1737 /* 1738 * Copy option fields and padding (nop) to mbuf. 1739 */ 1740 ip_srcrt.nop = IPOPT_NOP; 1741 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1742 bcopy((caddr_t)&ip_srcrt.nop, 1743 mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ); 1744 q = (struct in_addr *)(mtod(m, caddr_t) + 1745 sizeof(struct in_addr) + OPTSIZ); 1746 #undef OPTSIZ 1747 /* 1748 * Record return path as an IP source route, 1749 * reversing the path (pointers are now aligned). 1750 */ 1751 while (p >= ip_srcrt.route) { 1752 #ifdef DIAGNOSTIC 1753 if (ipprintfs) 1754 printf(" %x", ntohl(q->s_addr)); 1755 #endif 1756 *q++ = *p--; 1757 } 1758 /* 1759 * Last hop goes to final destination. 1760 */ 1761 *q = ip_srcrt.dst; 1762 #ifdef DIAGNOSTIC 1763 if (ipprintfs) 1764 printf(" %x\n", ntohl(q->s_addr)); 1765 #endif 1766 return (m); 1767 } 1768 1769 /* 1770 * Strip out IP options, at higher 1771 * level protocol in the kernel. 1772 * Second argument is buffer to which options 1773 * will be moved, and return value is their length. 1774 * XXX should be deleted; last arg currently ignored. 1775 */ 1776 void 1777 ip_stripoptions(struct mbuf *m, struct mbuf *mopt) 1778 { 1779 int i; 1780 struct ip *ip = mtod(m, struct ip *); 1781 caddr_t opts; 1782 int olen; 1783 1784 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1785 opts = (caddr_t)(ip + 1); 1786 i = m->m_len - (sizeof (struct ip) + olen); 1787 bcopy(opts + olen, opts, (unsigned)i); 1788 m->m_len -= olen; 1789 if (m->m_flags & M_PKTHDR) 1790 m->m_pkthdr.len -= olen; 1791 ip->ip_len = htons(ntohs(ip->ip_len) - olen); 1792 ip->ip_hl = sizeof (struct ip) >> 2; 1793 } 1794 1795 const int inetctlerrmap[PRC_NCMDS] = { 1796 0, 0, 0, 0, 1797 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1798 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1799 EMSGSIZE, EHOSTUNREACH, 0, 0, 1800 0, 0, 0, 0, 1801 ENOPROTOOPT 1802 }; 1803 1804 /* 1805 * Forward a packet. If some error occurs return the sender 1806 * an icmp packet. Note we can't always generate a meaningful 1807 * icmp message because icmp doesn't have a large enough repertoire 1808 * of codes and types. 1809 * 1810 * If not forwarding, just drop the packet. This could be confusing 1811 * if ipforwarding was zero but some routing protocol was advancing 1812 * us as a gateway to somewhere. However, we must let the routing 1813 * protocol deal with that. 1814 * 1815 * The srcrt parameter indicates whether the packet is being forwarded 1816 * via a source route. 1817 */ 1818 void 1819 ip_forward(struct mbuf *m, int srcrt) 1820 { 1821 struct ip *ip = mtod(m, struct ip *); 1822 struct sockaddr_in *sin; 1823 struct rtentry *rt; 1824 int error, type = 0, code = 0; 1825 struct mbuf *mcopy; 1826 n_long dest; 1827 struct ifnet *destifp; 1828 #if defined(IPSEC) || defined(FAST_IPSEC) 1829 struct ifnet dummyifp; 1830 #endif 1831 1832 /* 1833 * We are now in the output path. 1834 */ 1835 MCLAIM(m, &ip_tx_mowner); 1836 1837 /* 1838 * Clear any in-bound checksum flags for this packet. 1839 */ 1840 m->m_pkthdr.csum_flags = 0; 1841 1842 dest = 0; 1843 #ifdef DIAGNOSTIC 1844 if (ipprintfs) 1845 printf("forward: src %2.2x dst %2.2x ttl %x\n", 1846 ntohl(ip->ip_src.s_addr), 1847 ntohl(ip->ip_dst.s_addr), ip->ip_ttl); 1848 #endif 1849 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1850 ipstat.ips_cantforward++; 1851 m_freem(m); 1852 return; 1853 } 1854 if (ip->ip_ttl <= IPTTLDEC) { 1855 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1856 return; 1857 } 1858 ip->ip_ttl -= IPTTLDEC; 1859 1860 sin = satosin(&ipforward_rt.ro_dst); 1861 if ((rt = ipforward_rt.ro_rt) == 0 || 1862 !in_hosteq(ip->ip_dst, sin->sin_addr)) { 1863 if (ipforward_rt.ro_rt) { 1864 RTFREE(ipforward_rt.ro_rt); 1865 ipforward_rt.ro_rt = 0; 1866 } 1867 sin->sin_family = AF_INET; 1868 sin->sin_len = sizeof(struct sockaddr_in); 1869 sin->sin_addr = ip->ip_dst; 1870 1871 rtalloc(&ipforward_rt); 1872 if (ipforward_rt.ro_rt == 0) { 1873 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1874 return; 1875 } 1876 rt = ipforward_rt.ro_rt; 1877 } 1878 1879 /* 1880 * Save at most 68 bytes of the packet in case 1881 * we need to generate an ICMP message to the src. 1882 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1883 */ 1884 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1885 if (mcopy) 1886 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1887 1888 /* 1889 * If forwarding packet using same interface that it came in on, 1890 * perhaps should send a redirect to sender to shortcut a hop. 1891 * Only send redirect if source is sending directly to us, 1892 * and if packet was not source routed (or has any options). 1893 * Also, don't send redirect if forwarding using a default route 1894 * or a route modified by a redirect. 1895 */ 1896 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1897 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1898 !in_nullhost(satosin(rt_key(rt))->sin_addr) && 1899 ipsendredirects && !srcrt) { 1900 if (rt->rt_ifa && 1901 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1902 ifatoia(rt->rt_ifa)->ia_subnet) { 1903 if (rt->rt_flags & RTF_GATEWAY) 1904 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1905 else 1906 dest = ip->ip_dst.s_addr; 1907 /* 1908 * Router requirements says to only send host 1909 * redirects. 1910 */ 1911 type = ICMP_REDIRECT; 1912 code = ICMP_REDIRECT_HOST; 1913 #ifdef DIAGNOSTIC 1914 if (ipprintfs) 1915 printf("redirect (%d) to %x\n", code, 1916 (u_int32_t)dest); 1917 #endif 1918 } 1919 } 1920 1921 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1922 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1923 (struct ip_moptions *)NULL, (struct socket *)NULL); 1924 1925 if (error) 1926 ipstat.ips_cantforward++; 1927 else { 1928 ipstat.ips_forward++; 1929 if (type) 1930 ipstat.ips_redirectsent++; 1931 else { 1932 if (mcopy) { 1933 #ifdef GATEWAY 1934 if (mcopy->m_flags & M_CANFASTFWD) 1935 ipflow_create(&ipforward_rt, mcopy); 1936 #endif 1937 m_freem(mcopy); 1938 } 1939 return; 1940 } 1941 } 1942 if (mcopy == NULL) 1943 return; 1944 destifp = NULL; 1945 1946 switch (error) { 1947 1948 case 0: /* forwarded, but need redirect */ 1949 /* type, code set above */ 1950 break; 1951 1952 case ENETUNREACH: /* shouldn't happen, checked above */ 1953 case EHOSTUNREACH: 1954 case ENETDOWN: 1955 case EHOSTDOWN: 1956 default: 1957 type = ICMP_UNREACH; 1958 code = ICMP_UNREACH_HOST; 1959 break; 1960 1961 case EMSGSIZE: 1962 type = ICMP_UNREACH; 1963 code = ICMP_UNREACH_NEEDFRAG; 1964 #if !defined(IPSEC) && !defined(FAST_IPSEC) 1965 if (ipforward_rt.ro_rt) 1966 destifp = ipforward_rt.ro_rt->rt_ifp; 1967 #else 1968 /* 1969 * If the packet is routed over IPsec tunnel, tell the 1970 * originator the tunnel MTU. 1971 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1972 * XXX quickhack!!! 1973 */ 1974 if (ipforward_rt.ro_rt) { 1975 struct secpolicy *sp; 1976 int ipsecerror; 1977 size_t ipsechdr; 1978 struct route *ro; 1979 1980 sp = ipsec4_getpolicybyaddr(mcopy, 1981 IPSEC_DIR_OUTBOUND, IP_FORWARDING, 1982 &ipsecerror); 1983 1984 if (sp == NULL) 1985 destifp = ipforward_rt.ro_rt->rt_ifp; 1986 else { 1987 /* count IPsec header size */ 1988 ipsechdr = ipsec4_hdrsiz(mcopy, 1989 IPSEC_DIR_OUTBOUND, NULL); 1990 1991 /* 1992 * find the correct route for outer IPv4 1993 * header, compute tunnel MTU. 1994 * 1995 * XXX BUG ALERT 1996 * The "dummyifp" code relies upon the fact 1997 * that icmp_error() touches only ifp->if_mtu. 1998 */ 1999 /*XXX*/ 2000 destifp = NULL; 2001 if (sp->req != NULL 2002 && sp->req->sav != NULL 2003 && sp->req->sav->sah != NULL) { 2004 ro = &sp->req->sav->sah->sa_route; 2005 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 2006 dummyifp.if_mtu = 2007 ro->ro_rt->rt_rmx.rmx_mtu ? 2008 ro->ro_rt->rt_rmx.rmx_mtu : 2009 ro->ro_rt->rt_ifp->if_mtu; 2010 dummyifp.if_mtu -= ipsechdr; 2011 destifp = &dummyifp; 2012 } 2013 } 2014 2015 #ifdef IPSEC 2016 key_freesp(sp); 2017 #else 2018 KEY_FREESP(&sp); 2019 #endif 2020 } 2021 } 2022 #endif /*IPSEC*/ 2023 ipstat.ips_cantfrag++; 2024 break; 2025 2026 case ENOBUFS: 2027 #if 1 2028 /* 2029 * a router should not generate ICMP_SOURCEQUENCH as 2030 * required in RFC1812 Requirements for IP Version 4 Routers. 2031 * source quench could be a big problem under DoS attacks, 2032 * or if the underlying interface is rate-limited. 2033 */ 2034 if (mcopy) 2035 m_freem(mcopy); 2036 return; 2037 #else 2038 type = ICMP_SOURCEQUENCH; 2039 code = 0; 2040 break; 2041 #endif 2042 } 2043 icmp_error(mcopy, type, code, dest, destifp); 2044 } 2045 2046 void 2047 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2048 struct mbuf *m) 2049 { 2050 2051 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2052 struct timeval tv; 2053 2054 microtime(&tv); 2055 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2056 SCM_TIMESTAMP, SOL_SOCKET); 2057 if (*mp) 2058 mp = &(*mp)->m_next; 2059 } 2060 if (inp->inp_flags & INP_RECVDSTADDR) { 2061 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2062 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2063 if (*mp) 2064 mp = &(*mp)->m_next; 2065 } 2066 #ifdef notyet 2067 /* 2068 * XXX 2069 * Moving these out of udp_input() made them even more broken 2070 * than they already were. 2071 * - fenner@parc.xerox.com 2072 */ 2073 /* options were tossed already */ 2074 if (inp->inp_flags & INP_RECVOPTS) { 2075 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2076 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2077 if (*mp) 2078 mp = &(*mp)->m_next; 2079 } 2080 /* ip_srcroute doesn't do what we want here, need to fix */ 2081 if (inp->inp_flags & INP_RECVRETOPTS) { 2082 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2083 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2084 if (*mp) 2085 mp = &(*mp)->m_next; 2086 } 2087 #endif 2088 if (inp->inp_flags & INP_RECVIF) { 2089 struct sockaddr_dl sdl; 2090 2091 sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]); 2092 sdl.sdl_family = AF_LINK; 2093 sdl.sdl_index = m->m_pkthdr.rcvif ? 2094 m->m_pkthdr.rcvif->if_index : 0; 2095 sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0; 2096 *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len, 2097 IP_RECVIF, IPPROTO_IP); 2098 if (*mp) 2099 mp = &(*mp)->m_next; 2100 } 2101 } 2102 2103 /* 2104 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the 2105 * range of the new value and tweaks timers if it changes. 2106 */ 2107 static int 2108 sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS) 2109 { 2110 int error, tmp; 2111 struct sysctlnode node; 2112 2113 node = *rnode; 2114 tmp = ip_mtudisc_timeout; 2115 node.sysctl_data = &tmp; 2116 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 2117 if (error || newp == NULL) 2118 return (error); 2119 if (tmp < 0) 2120 return (EINVAL); 2121 2122 ip_mtudisc_timeout = tmp; 2123 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout); 2124 2125 return (0); 2126 } 2127 2128 #ifdef GATEWAY 2129 /* 2130 * sysctl helper routine for net.inet.ip.maxflows. apparently if 2131 * maxflows is even looked up, we "reap flows". 2132 */ 2133 static int 2134 sysctl_net_inet_ip_maxflows(SYSCTLFN_ARGS) 2135 { 2136 int s; 2137 2138 s = sysctl_lookup(SYSCTLFN_CALL(rnode)); 2139 if (s) 2140 return (s); 2141 2142 s = splsoftnet(); 2143 ipflow_reap(0); 2144 splx(s); 2145 2146 return (0); 2147 } 2148 #endif /* GATEWAY */ 2149 2150 2151 SYSCTL_SETUP(sysctl_net_inet_ip_setup, "sysctl net.inet.ip subtree setup") 2152 { 2153 extern int subnetsarelocal, hostzeroisbroadcast; 2154 2155 sysctl_createv(clog, 0, NULL, NULL, 2156 CTLFLAG_PERMANENT, 2157 CTLTYPE_NODE, "net", NULL, 2158 NULL, 0, NULL, 0, 2159 CTL_NET, CTL_EOL); 2160 sysctl_createv(clog, 0, NULL, NULL, 2161 CTLFLAG_PERMANENT, 2162 CTLTYPE_NODE, "inet", 2163 SYSCTL_DESCR("PF_INET related settings"), 2164 NULL, 0, NULL, 0, 2165 CTL_NET, PF_INET, CTL_EOL); 2166 sysctl_createv(clog, 0, NULL, NULL, 2167 CTLFLAG_PERMANENT, 2168 CTLTYPE_NODE, "ip", 2169 SYSCTL_DESCR("IPv4 related settings"), 2170 NULL, 0, NULL, 0, 2171 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL); 2172 2173 sysctl_createv(clog, 0, NULL, NULL, 2174 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2175 CTLTYPE_INT, "forwarding", 2176 SYSCTL_DESCR("Enable forwarding of INET datagrams"), 2177 NULL, 0, &ipforwarding, 0, 2178 CTL_NET, PF_INET, IPPROTO_IP, 2179 IPCTL_FORWARDING, CTL_EOL); 2180 sysctl_createv(clog, 0, NULL, NULL, 2181 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2182 CTLTYPE_INT, "redirect", 2183 SYSCTL_DESCR("Enable sending of ICMP redirect messages"), 2184 NULL, 0, &ipsendredirects, 0, 2185 CTL_NET, PF_INET, IPPROTO_IP, 2186 IPCTL_SENDREDIRECTS, CTL_EOL); 2187 sysctl_createv(clog, 0, NULL, NULL, 2188 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2189 CTLTYPE_INT, "ttl", 2190 SYSCTL_DESCR("Default TTL for an INET datagram"), 2191 NULL, 0, &ip_defttl, 0, 2192 CTL_NET, PF_INET, IPPROTO_IP, 2193 IPCTL_DEFTTL, CTL_EOL); 2194 #ifdef IPCTL_DEFMTU 2195 sysctl_createv(clog, 0, NULL, NULL, 2196 CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */, 2197 CTLTYPE_INT, "mtu", 2198 SYSCTL_DESCR("Default MTA for an INET route"), 2199 NULL, 0, &ip_mtu, 0, 2200 CTL_NET, PF_INET, IPPROTO_IP, 2201 IPCTL_DEFMTU, CTL_EOL); 2202 #endif /* IPCTL_DEFMTU */ 2203 sysctl_createv(clog, 0, NULL, NULL, 2204 CTLFLAG_PERMANENT|CTLFLAG_READONLY1, 2205 CTLTYPE_INT, "forwsrcrt", 2206 SYSCTL_DESCR("Enable forwarding of source-routed " 2207 "datagrams"), 2208 NULL, 0, &ip_forwsrcrt, 0, 2209 CTL_NET, PF_INET, IPPROTO_IP, 2210 IPCTL_FORWSRCRT, CTL_EOL); 2211 sysctl_createv(clog, 0, NULL, NULL, 2212 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2213 CTLTYPE_INT, "directed-broadcast", 2214 SYSCTL_DESCR("Enable forwarding of broadcast datagrams"), 2215 NULL, 0, &ip_directedbcast, 0, 2216 CTL_NET, PF_INET, IPPROTO_IP, 2217 IPCTL_DIRECTEDBCAST, CTL_EOL); 2218 sysctl_createv(clog, 0, NULL, NULL, 2219 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2220 CTLTYPE_INT, "allowsrcrt", 2221 SYSCTL_DESCR("Accept source-routed datagrams"), 2222 NULL, 0, &ip_allowsrcrt, 0, 2223 CTL_NET, PF_INET, IPPROTO_IP, 2224 IPCTL_ALLOWSRCRT, CTL_EOL); 2225 sysctl_createv(clog, 0, NULL, NULL, 2226 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2227 CTLTYPE_INT, "subnetsarelocal", 2228 SYSCTL_DESCR("Whether logical subnets are considered " 2229 "local"), 2230 NULL, 0, &subnetsarelocal, 0, 2231 CTL_NET, PF_INET, IPPROTO_IP, 2232 IPCTL_SUBNETSARELOCAL, CTL_EOL); 2233 sysctl_createv(clog, 0, NULL, NULL, 2234 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2235 CTLTYPE_INT, "mtudisc", 2236 SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"), 2237 NULL, 0, &ip_mtudisc, 0, 2238 CTL_NET, PF_INET, IPPROTO_IP, 2239 IPCTL_MTUDISC, CTL_EOL); 2240 sysctl_createv(clog, 0, NULL, NULL, 2241 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2242 CTLTYPE_INT, "anonportmin", 2243 SYSCTL_DESCR("Lowest ephemeral port number to assign"), 2244 sysctl_net_inet_ip_ports, 0, &anonportmin, 0, 2245 CTL_NET, PF_INET, IPPROTO_IP, 2246 IPCTL_ANONPORTMIN, CTL_EOL); 2247 sysctl_createv(clog, 0, NULL, NULL, 2248 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2249 CTLTYPE_INT, "anonportmax", 2250 SYSCTL_DESCR("Highest ephemeral port number to assign"), 2251 sysctl_net_inet_ip_ports, 0, &anonportmax, 0, 2252 CTL_NET, PF_INET, IPPROTO_IP, 2253 IPCTL_ANONPORTMAX, CTL_EOL); 2254 sysctl_createv(clog, 0, NULL, NULL, 2255 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2256 CTLTYPE_INT, "mtudisctimeout", 2257 SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"), 2258 sysctl_net_inet_ip_pmtudto, 0, &ip_mtudisc_timeout, 0, 2259 CTL_NET, PF_INET, IPPROTO_IP, 2260 IPCTL_MTUDISCTIMEOUT, CTL_EOL); 2261 #ifdef GATEWAY 2262 sysctl_createv(clog, 0, NULL, NULL, 2263 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2264 CTLTYPE_INT, "maxflows", 2265 SYSCTL_DESCR("Number of flows for fast forwarding"), 2266 sysctl_net_inet_ip_maxflows, 0, &ip_maxflows, 0, 2267 CTL_NET, PF_INET, IPPROTO_IP, 2268 IPCTL_MAXFLOWS, CTL_EOL); 2269 #endif /* GATEWAY */ 2270 sysctl_createv(clog, 0, NULL, NULL, 2271 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2272 CTLTYPE_INT, "hostzerobroadcast", 2273 SYSCTL_DESCR("All zeroes address is broadcast address"), 2274 NULL, 0, &hostzeroisbroadcast, 0, 2275 CTL_NET, PF_INET, IPPROTO_IP, 2276 IPCTL_HOSTZEROBROADCAST, CTL_EOL); 2277 #if NGIF > 0 2278 sysctl_createv(clog, 0, NULL, NULL, 2279 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2280 CTLTYPE_INT, "gifttl", 2281 SYSCTL_DESCR("Default TTL for a gif tunnel datagram"), 2282 NULL, 0, &ip_gif_ttl, 0, 2283 CTL_NET, PF_INET, IPPROTO_IP, 2284 IPCTL_GIF_TTL, CTL_EOL); 2285 #endif /* NGIF */ 2286 #ifndef IPNOPRIVPORTS 2287 sysctl_createv(clog, 0, NULL, NULL, 2288 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2289 CTLTYPE_INT, "lowportmin", 2290 SYSCTL_DESCR("Lowest privileged ephemeral port number " 2291 "to assign"), 2292 sysctl_net_inet_ip_ports, 0, &lowportmin, 0, 2293 CTL_NET, PF_INET, IPPROTO_IP, 2294 IPCTL_LOWPORTMIN, CTL_EOL); 2295 sysctl_createv(clog, 0, NULL, NULL, 2296 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2297 CTLTYPE_INT, "lowportmax", 2298 SYSCTL_DESCR("Highest privileged ephemeral port number " 2299 "to assign"), 2300 sysctl_net_inet_ip_ports, 0, &lowportmax, 0, 2301 CTL_NET, PF_INET, IPPROTO_IP, 2302 IPCTL_LOWPORTMAX, CTL_EOL); 2303 #endif /* IPNOPRIVPORTS */ 2304 sysctl_createv(clog, 0, NULL, NULL, 2305 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2306 CTLTYPE_INT, "maxfragpackets", 2307 SYSCTL_DESCR("Maximum number of fragments to retain for " 2308 "possible reassembly"), 2309 NULL, 0, &ip_maxfragpackets, 0, 2310 CTL_NET, PF_INET, IPPROTO_IP, 2311 IPCTL_MAXFRAGPACKETS, CTL_EOL); 2312 #if NGRE > 0 2313 sysctl_createv(clog, 0, NULL, NULL, 2314 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2315 CTLTYPE_INT, "grettl", 2316 SYSCTL_DESCR("Default TTL for a gre tunnel datagram"), 2317 NULL, 0, &ip_gre_ttl, 0, 2318 CTL_NET, PF_INET, IPPROTO_IP, 2319 IPCTL_GRE_TTL, CTL_EOL); 2320 #endif /* NGRE */ 2321 sysctl_createv(clog, 0, NULL, NULL, 2322 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2323 CTLTYPE_INT, "checkinterface", 2324 SYSCTL_DESCR("Enable receive side of Strong ES model " 2325 "from RFC1122"), 2326 NULL, 0, &ip_checkinterface, 0, 2327 CTL_NET, PF_INET, IPPROTO_IP, 2328 IPCTL_CHECKINTERFACE, CTL_EOL); 2329 sysctl_createv(clog, 0, NULL, NULL, 2330 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2331 CTLTYPE_INT, "random_id", 2332 SYSCTL_DESCR("Assign random ip_id values"), 2333 NULL, 0, &ip_do_randomid, 0, 2334 CTL_NET, PF_INET, IPPROTO_IP, 2335 IPCTL_RANDOMID, CTL_EOL); 2336 sysctl_createv(clog, 0, NULL, NULL, 2337 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2338 CTLTYPE_INT, "do_loopback_cksum", 2339 SYSCTL_DESCR("Perform IP checksum on loopback"), 2340 NULL, 0, &ip_do_loopback_cksum, 0, 2341 CTL_NET, PF_INET, IPPROTO_IP, 2342 IPCTL_LOOPBACKCKSUM, CTL_EOL); 2343 }
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