1 /* $NetBSD: ip_input.c,v 1.196 2004/01/15 05:13:17 itojun 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 1.196 2004/01/15 05:13:17 itojun 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 extern struct domain inetdomain; 223 int ipqmaxlen = IFQ_MAXLEN; 224 u_long in_ifaddrhash; /* size of hash table - 1 */ 225 int in_ifaddrentries; /* total number of addrs */ 226 struct in_ifaddrhead in_ifaddrhead; 227 struct in_ifaddrhashhead *in_ifaddrhashtbl; 228 u_long in_multihash; /* size of hash table - 1 */ 229 int in_multientries; /* total number of addrs */ 230 struct in_multihashhead *in_multihashtbl; 231 struct ifqueue ipintrq; 232 struct ipstat ipstat; 233 uint16_t ip_id; 234 235 #ifdef PFIL_HOOKS 236 struct pfil_head inet_pfil_hook; 237 #endif 238 239 /* 240 * Cached copy of nmbclusters. If nbclusters is different, 241 * recalculate IP parameters derived from nmbclusters. 242 */ 243 static int ip_nmbclusters; /* copy of nmbclusters */ 244 static void ip_nmbclusters_changed __P((void)); /* recalc limits */ 245 246 #define CHECK_NMBCLUSTER_PARAMS() \ 247 do { \ 248 if (__predict_false(ip_nmbclusters != nmbclusters)) \ 249 ip_nmbclusters_changed(); \ 250 } while (/*CONSTCOND*/0) 251 252 /* IP datagram reassembly queues (hashed) */ 253 #define IPREASS_NHASH_LOG2 6 254 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 255 #define IPREASS_HMASK (IPREASS_NHASH - 1) 256 #define IPREASS_HASH(x,y) \ 257 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 258 struct ipqhead ipq[IPREASS_NHASH]; 259 int ipq_locked; 260 static int ip_nfragpackets; /* packets in reass queue */ 261 static int ip_nfrags; /* total fragments in reass queues */ 262 263 int ip_maxfragpackets = 200; /* limit on packets. XXX sysctl */ 264 int ip_maxfrags; /* limit on fragments. XXX sysctl */ 265 266 267 /* 268 * Additive-Increase/Multiplicative-Decrease (AIMD) strategy for 269 * IP reassembly queue buffer managment. 270 * 271 * We keep a count of total IP fragments (NB: not fragmented packets!) 272 * awaiting reassembly (ip_nfrags) and a limit (ip_maxfrags) on fragments. 273 * If ip_nfrags exceeds ip_maxfrags the limit, we drop half the 274 * total fragments in reassembly queues.This AIMD policy avoids 275 * repeatedly deleting single packets under heavy fragmentation load 276 * (e.g., from lossy NFS peers). 277 */ 278 static u_int ip_reass_ttl_decr __P((u_int ticks)); 279 static void ip_reass_drophalf __P((void)); 280 281 282 static __inline int ipq_lock_try __P((void)); 283 static __inline void ipq_unlock __P((void)); 284 285 static __inline int 286 ipq_lock_try() 287 { 288 int s; 289 290 /* 291 * Use splvm() -- we're blocking things that would cause 292 * mbuf allocation. 293 */ 294 s = splvm(); 295 if (ipq_locked) { 296 splx(s); 297 return (0); 298 } 299 ipq_locked = 1; 300 splx(s); 301 return (1); 302 } 303 304 static __inline void 305 ipq_unlock() 306 { 307 int s; 308 309 s = splvm(); 310 ipq_locked = 0; 311 splx(s); 312 } 313 314 #ifdef DIAGNOSTIC 315 #define IPQ_LOCK() \ 316 do { \ 317 if (ipq_lock_try() == 0) { \ 318 printf("%s:%d: ipq already locked\n", __FILE__, __LINE__); \ 319 panic("ipq_lock"); \ 320 } \ 321 } while (/*CONSTCOND*/ 0) 322 #define IPQ_LOCK_CHECK() \ 323 do { \ 324 if (ipq_locked == 0) { \ 325 printf("%s:%d: ipq lock not held\n", __FILE__, __LINE__); \ 326 panic("ipq lock check"); \ 327 } \ 328 } while (/*CONSTCOND*/ 0) 329 #else 330 #define IPQ_LOCK() (void) ipq_lock_try() 331 #define IPQ_LOCK_CHECK() /* nothing */ 332 #endif 333 334 #define IPQ_UNLOCK() ipq_unlock() 335 336 struct pool inmulti_pool; 337 struct pool ipqent_pool; 338 339 #ifdef INET_CSUM_COUNTERS 340 #include <sys/device.h> 341 342 struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 343 NULL, "inet", "hwcsum bad"); 344 struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 345 NULL, "inet", "hwcsum ok"); 346 struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, 347 NULL, "inet", "swcsum"); 348 349 #define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ 350 351 #else 352 353 #define INET_CSUM_COUNTER_INCR(ev) /* nothing */ 354 355 #endif /* INET_CSUM_COUNTERS */ 356 357 /* 358 * We need to save the IP options in case a protocol wants to respond 359 * to an incoming packet over the same route if the packet got here 360 * using IP source routing. This allows connection establishment and 361 * maintenance when the remote end is on a network that is not known 362 * to us. 363 */ 364 int ip_nhops = 0; 365 static struct ip_srcrt { 366 struct in_addr dst; /* final destination */ 367 char nop; /* one NOP to align */ 368 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 369 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 370 } ip_srcrt; 371 372 static void save_rte __P((u_char *, struct in_addr)); 373 374 #ifdef MBUFTRACE 375 struct mowner ip_rx_mowner = { "internet", "rx" }; 376 struct mowner ip_tx_mowner = { "internet", "tx" }; 377 #endif 378 379 /* 380 * Compute IP limits derived from the value of nmbclusters. 381 */ 382 static void 383 ip_nmbclusters_changed(void) 384 { 385 ip_maxfrags = nmbclusters / 4; 386 ip_nmbclusters = nmbclusters; 387 } 388 389 /* 390 * IP initialization: fill in IP protocol switch table. 391 * All protocols not implemented in kernel go to raw IP protocol handler. 392 */ 393 void 394 ip_init() 395 { 396 struct protosw *pr; 397 int i; 398 399 pool_init(&inmulti_pool, sizeof(struct in_multi), 0, 0, 0, "inmltpl", 400 NULL); 401 pool_init(&ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl", 402 NULL); 403 404 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 405 if (pr == 0) 406 panic("ip_init"); 407 for (i = 0; i < IPPROTO_MAX; i++) 408 ip_protox[i] = pr - inetsw; 409 for (pr = inetdomain.dom_protosw; 410 pr < inetdomain.dom_protoswNPROTOSW; pr++) 411 if (pr->pr_domain->dom_family == PF_INET && 412 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 413 ip_protox[pr->pr_protocol] = pr - inetsw; 414 415 for (i = 0; i < IPREASS_NHASH; i++) 416 LIST_INIT(&ipq[i]); 417 418 ip_id = time.tv_sec & 0xfffff; 419 420 ipintrq.ifq_maxlen = ipqmaxlen; 421 ip_nmbclusters_changed(); 422 423 TAILQ_INIT(&in_ifaddrhead); 424 in_ifaddrhashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IFADDR, 425 M_WAITOK, &in_ifaddrhash); 426 in_multihashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IPMADDR, 427 M_WAITOK, &in_multihash); 428 ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout); 429 #ifdef GATEWAY 430 ipflow_init(); 431 #endif 432 433 #ifdef PFIL_HOOKS 434 /* Register our Packet Filter hook. */ 435 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 436 inet_pfil_hook.ph_af = AF_INET; 437 i = pfil_head_register(&inet_pfil_hook); 438 if (i != 0) 439 printf("ip_init: WARNING: unable to register pfil hook, " 440 "error %d\n", i); 441 #endif /* PFIL_HOOKS */ 442 443 #ifdef INET_CSUM_COUNTERS 444 evcnt_attach_static(&ip_hwcsum_bad); 445 evcnt_attach_static(&ip_hwcsum_ok); 446 evcnt_attach_static(&ip_swcsum); 447 #endif /* INET_CSUM_COUNTERS */ 448 449 #ifdef MBUFTRACE 450 MOWNER_ATTACH(&ip_tx_mowner); 451 MOWNER_ATTACH(&ip_rx_mowner); 452 #endif /* MBUFTRACE */ 453 } 454 455 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 456 struct route ipforward_rt; 457 458 /* 459 * IP software interrupt routine 460 */ 461 void 462 ipintr() 463 { 464 int s; 465 struct mbuf *m; 466 467 while (1) { 468 s = splnet(); 469 IF_DEQUEUE(&ipintrq, m); 470 splx(s); 471 if (m == 0) 472 return; 473 MCLAIM(m, &ip_rx_mowner); 474 ip_input(m); 475 } 476 } 477 478 /* 479 * Ip input routine. Checksum and byte swap header. If fragmented 480 * try to reassemble. Process options. Pass to next level. 481 */ 482 void 483 ip_input(struct mbuf *m) 484 { 485 struct ip *ip = NULL; 486 struct ipq *fp; 487 struct in_ifaddr *ia; 488 struct ifaddr *ifa; 489 struct ipqent *ipqe; 490 int hlen = 0, mff, len; 491 int downmatch; 492 int checkif; 493 int srcrt = 0; 494 u_int hash; 495 #ifdef FAST_IPSEC 496 struct m_tag *mtag; 497 struct tdb_ident *tdbi; 498 struct secpolicy *sp; 499 int s, error; 500 #endif /* FAST_IPSEC */ 501 502 MCLAIM(m, &ip_rx_mowner); 503 #ifdef DIAGNOSTIC 504 if ((m->m_flags & M_PKTHDR) == 0) 505 panic("ipintr no HDR"); 506 #endif 507 508 /* 509 * If no IP addresses have been set yet but the interfaces 510 * are receiving, can't do anything with incoming packets yet. 511 */ 512 if (TAILQ_FIRST(&in_ifaddrhead) == 0) 513 goto bad; 514 ipstat.ips_total++; 515 /* 516 * If the IP header is not aligned, slurp it up into a new 517 * mbuf with space for link headers, in the event we forward 518 * it. Otherwise, if it is aligned, make sure the entire 519 * base IP header is in the first mbuf of the chain. 520 */ 521 if (IP_HDR_ALIGNED_P(mtod(m, caddr_t)) == 0) { 522 if ((m = m_copyup(m, sizeof(struct ip), 523 (max_linkhdr + 3) & ~3)) == NULL) { 524 /* XXXJRT new stat, please */ 525 ipstat.ips_toosmall++; 526 return; 527 } 528 } else if (__predict_false(m->m_len < sizeof (struct ip))) { 529 if ((m = m_pullup(m, sizeof (struct ip))) == NULL) { 530 ipstat.ips_toosmall++; 531 return; 532 } 533 } 534 ip = mtod(m, struct ip *); 535 if (ip->ip_v != IPVERSION) { 536 ipstat.ips_badvers++; 537 goto bad; 538 } 539 hlen = ip->ip_hl << 2; 540 if (hlen < sizeof(struct ip)) { /* minimum header length */ 541 ipstat.ips_badhlen++; 542 goto bad; 543 } 544 if (hlen > m->m_len) { 545 if ((m = m_pullup(m, hlen)) == 0) { 546 ipstat.ips_badhlen++; 547 return; 548 } 549 ip = mtod(m, struct ip *); 550 } 551 552 /* 553 * RFC1122: packets with a multicast source address are 554 * not allowed. 555 */ 556 if (IN_MULTICAST(ip->ip_src.s_addr)) { 557 ipstat.ips_badaddr++; 558 goto bad; 559 } 560 561 /* 127/8 must not appear on wire - RFC1122 */ 562 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 563 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 564 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 565 ipstat.ips_badaddr++; 566 goto bad; 567 } 568 } 569 570 switch (m->m_pkthdr.csum_flags & 571 ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_IPv4) | 572 M_CSUM_IPv4_BAD)) { 573 case M_CSUM_IPv4|M_CSUM_IPv4_BAD: 574 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad); 575 goto badcsum; 576 577 case M_CSUM_IPv4: 578 /* Checksum was okay. */ 579 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok); 580 break; 581 582 default: 583 /* Must compute it ourselves. */ 584 INET_CSUM_COUNTER_INCR(&ip_swcsum); 585 if (in_cksum(m, hlen) != 0) 586 goto bad; 587 break; 588 } 589 590 /* Retrieve the packet length. */ 591 len = ntohs(ip->ip_len); 592 593 /* 594 * Check for additional length bogosity 595 */ 596 if (len < hlen) { 597 ipstat.ips_badlen++; 598 goto bad; 599 } 600 601 /* 602 * Check that the amount of data in the buffers 603 * is as at least much as the IP header would have us expect. 604 * Trim mbufs if longer than we expect. 605 * Drop packet if shorter than we expect. 606 */ 607 if (m->m_pkthdr.len < len) { 608 ipstat.ips_tooshort++; 609 goto bad; 610 } 611 if (m->m_pkthdr.len > len) { 612 if (m->m_len == m->m_pkthdr.len) { 613 m->m_len = len; 614 m->m_pkthdr.len = len; 615 } else 616 m_adj(m, len - m->m_pkthdr.len); 617 } 618 619 #if defined(IPSEC) 620 /* ipflow (IP fast forwarding) is not compatible with IPsec. */ 621 m->m_flags &= ~M_CANFASTFWD; 622 #else 623 /* 624 * Assume that we can create a fast-forward IP flow entry 625 * based on this packet. 626 */ 627 m->m_flags |= M_CANFASTFWD; 628 #endif 629 630 #ifdef PFIL_HOOKS 631 /* 632 * Run through list of hooks for input packets. If there are any 633 * filters which require that additional packets in the flow are 634 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 635 * Note that filters must _never_ set this flag, as another filter 636 * in the list may have previously cleared it. 637 */ 638 /* 639 * let ipfilter look at packet on the wire, 640 * not the decapsulated packet. 641 */ 642 #ifdef IPSEC 643 if (!ipsec_getnhist(m)) 644 #elif defined(FAST_IPSEC) 645 if (!ipsec_indone(m)) 646 #else 647 if (1) 648 #endif 649 { 650 struct in_addr odst; 651 652 odst = ip->ip_dst; 653 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 654 PFIL_IN) != 0) 655 return; 656 if (m == NULL) 657 return; 658 ip = mtod(m, struct ip *); 659 hlen = ip->ip_hl << 2; 660 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 661 } 662 #endif /* PFIL_HOOKS */ 663 664 #ifdef ALTQ 665 /* XXX Temporary until ALTQ is changed to use a pfil hook */ 666 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 667 /* packet dropped by traffic conditioner */ 668 return; 669 } 670 #endif 671 672 /* 673 * Process options and, if not destined for us, 674 * ship it on. ip_dooptions returns 1 when an 675 * error was detected (causing an icmp message 676 * to be sent and the original packet to be freed). 677 */ 678 ip_nhops = 0; /* for source routed packets */ 679 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 680 return; 681 682 /* 683 * Enable a consistency check between the destination address 684 * and the arrival interface for a unicast packet (the RFC 1122 685 * strong ES model) if IP forwarding is disabled and the packet 686 * is not locally generated. 687 * 688 * XXX - Checking also should be disabled if the destination 689 * address is ipnat'ed to a different interface. 690 * 691 * XXX - Checking is incompatible with IP aliases added 692 * to the loopback interface instead of the interface where 693 * the packets are received. 694 * 695 * XXX - We need to add a per ifaddr flag for this so that 696 * we get finer grain control. 697 */ 698 checkif = ip_checkinterface && (ipforwarding == 0) && 699 (m->m_pkthdr.rcvif != NULL) && 700 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0); 701 702 /* 703 * Check our list of addresses, to see if the packet is for us. 704 * 705 * Traditional 4.4BSD did not consult IFF_UP at all. 706 * The behavior here is to treat addresses on !IFF_UP interface 707 * as not mine. 708 */ 709 downmatch = 0; 710 LIST_FOREACH(ia, &IN_IFADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 711 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) { 712 if (checkif && ia->ia_ifp != m->m_pkthdr.rcvif) 713 continue; 714 if ((ia->ia_ifp->if_flags & IFF_UP) != 0) 715 break; 716 else 717 downmatch++; 718 } 719 } 720 if (ia != NULL) 721 goto ours; 722 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 723 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrlist, ifa_list) { 724 if (ifa->ifa_addr->sa_family != AF_INET) 725 continue; 726 ia = ifatoia(ifa); 727 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) || 728 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) || 729 /* 730 * Look for all-0's host part (old broadcast addr), 731 * either for subnet or net. 732 */ 733 ip->ip_dst.s_addr == ia->ia_subnet || 734 ip->ip_dst.s_addr == ia->ia_net) 735 goto ours; 736 /* 737 * An interface with IP address zero accepts 738 * all packets that arrive on that interface. 739 */ 740 if (in_nullhost(ia->ia_addr.sin_addr)) 741 goto ours; 742 } 743 } 744 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 745 struct in_multi *inm; 746 #ifdef MROUTING 747 extern struct socket *ip_mrouter; 748 749 if (M_READONLY(m)) { 750 if ((m = m_pullup(m, hlen)) == 0) { 751 ipstat.ips_toosmall++; 752 return; 753 } 754 ip = mtod(m, struct ip *); 755 } 756 757 if (ip_mrouter) { 758 /* 759 * If we are acting as a multicast router, all 760 * incoming multicast packets are passed to the 761 * kernel-level multicast forwarding function. 762 * The packet is returned (relatively) intact; if 763 * ip_mforward() returns a non-zero value, the packet 764 * must be discarded, else it may be accepted below. 765 * 766 * (The IP ident field is put in the same byte order 767 * as expected when ip_mforward() is called from 768 * ip_output().) 769 */ 770 if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) { 771 ipstat.ips_cantforward++; 772 m_freem(m); 773 return; 774 } 775 776 /* 777 * The process-level routing demon needs to receive 778 * all multicast IGMP packets, whether or not this 779 * host belongs to their destination groups. 780 */ 781 if (ip->ip_p == IPPROTO_IGMP) 782 goto ours; 783 ipstat.ips_forward++; 784 } 785 #endif 786 /* 787 * See if we belong to the destination multicast group on the 788 * arrival interface. 789 */ 790 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 791 if (inm == NULL) { 792 ipstat.ips_cantforward++; 793 m_freem(m); 794 return; 795 } 796 goto ours; 797 } 798 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 799 in_nullhost(ip->ip_dst)) 800 goto ours; 801 802 /* 803 * Not for us; forward if possible and desirable. 804 */ 805 if (ipforwarding == 0) { 806 ipstat.ips_cantforward++; 807 m_freem(m); 808 } else { 809 /* 810 * If ip_dst matched any of my address on !IFF_UP interface, 811 * and there's no IFF_UP interface that matches ip_dst, 812 * send icmp unreach. Forwarding it will result in in-kernel 813 * forwarding loop till TTL goes to 0. 814 */ 815 if (downmatch) { 816 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 817 ipstat.ips_cantforward++; 818 return; 819 } 820 #ifdef IPSEC 821 if (ipsec4_in_reject(m, NULL)) { 822 ipsecstat.in_polvio++; 823 goto bad; 824 } 825 #endif 826 #ifdef FAST_IPSEC 827 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 828 s = splsoftnet(); 829 if (mtag != NULL) { 830 tdbi = (struct tdb_ident *)(mtag + 1); 831 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 832 } else { 833 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 834 IP_FORWARDING, &error); 835 } 836 if (sp == NULL) { /* NB: can happen if error */ 837 splx(s); 838 /*XXX error stat???*/ 839 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 840 goto bad; 841 } 842 843 /* 844 * Check security policy against packet attributes. 845 */ 846 error = ipsec_in_reject(sp, m); 847 KEY_FREESP(&sp); 848 splx(s); 849 if (error) { 850 ipstat.ips_cantforward++; 851 goto bad; 852 } 853 854 /* 855 * Peek at the outbound SP for this packet to determine if 856 * it's a Fast Forward candidate. 857 */ 858 mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL); 859 if (mtag != NULL) 860 m->m_flags &= ~M_CANFASTFWD; 861 else { 862 s = splsoftnet(); 863 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, 864 (IP_FORWARDING | 865 (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 866 &error, NULL); 867 if (sp != NULL) { 868 m->m_flags &= ~M_CANFASTFWD; 869 KEY_FREESP(&sp); 870 } 871 splx(s); 872 } 873 #endif /* FAST_IPSEC */ 874 875 ip_forward(m, srcrt); 876 } 877 return; 878 879 ours: 880 /* 881 * If offset or IP_MF are set, must reassemble. 882 * Otherwise, nothing need be done. 883 * (We could look in the reassembly queue to see 884 * if the packet was previously fragmented, 885 * but it's not worth the time; just let them time out.) 886 */ 887 if (ip->ip_off & ~htons(IP_DF|IP_RF)) { 888 if (M_READONLY(m)) { 889 if ((m = m_pullup(m, hlen)) == NULL) { 890 ipstat.ips_toosmall++; 891 goto bad; 892 } 893 ip = mtod(m, struct ip *); 894 } 895 896 /* 897 * Look for queue of fragments 898 * of this datagram. 899 */ 900 IPQ_LOCK(); 901 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 902 /* XXX LIST_FOREACH(fp, &ipq[hash], ipq_q) */ 903 for (fp = LIST_FIRST(&ipq[hash]); fp != NULL; 904 fp = LIST_NEXT(fp, ipq_q)) { 905 if (ip->ip_id == fp->ipq_id && 906 in_hosteq(ip->ip_src, fp->ipq_src) && 907 in_hosteq(ip->ip_dst, fp->ipq_dst) && 908 ip->ip_p == fp->ipq_p) 909 goto found; 910 911 } 912 fp = 0; 913 found: 914 915 /* 916 * Adjust ip_len to not reflect header, 917 * set ipqe_mff if more fragments are expected, 918 * convert offset of this to bytes. 919 */ 920 ip->ip_len = htons(ntohs(ip->ip_len) - hlen); 921 mff = (ip->ip_off & htons(IP_MF)) != 0; 922 if (mff) { 923 /* 924 * Make sure that fragments have a data length 925 * that's a non-zero multiple of 8 bytes. 926 */ 927 if (ntohs(ip->ip_len) == 0 || 928 (ntohs(ip->ip_len) & 0x7) != 0) { 929 ipstat.ips_badfrags++; 930 IPQ_UNLOCK(); 931 goto bad; 932 } 933 } 934 ip->ip_off = htons((ntohs(ip->ip_off) & IP_OFFMASK) << 3); 935 936 /* 937 * If datagram marked as having more fragments 938 * or if this is not the first fragment, 939 * attempt reassembly; if it succeeds, proceed. 940 */ 941 if (mff || ip->ip_off != htons(0)) { 942 ipstat.ips_fragments++; 943 ipqe = pool_get(&ipqent_pool, PR_NOWAIT); 944 if (ipqe == NULL) { 945 ipstat.ips_rcvmemdrop++; 946 IPQ_UNLOCK(); 947 goto bad; 948 } 949 ipqe->ipqe_mff = mff; 950 ipqe->ipqe_m = m; 951 ipqe->ipqe_ip = ip; 952 m = ip_reass(ipqe, fp, &ipq[hash]); 953 if (m == 0) { 954 IPQ_UNLOCK(); 955 return; 956 } 957 ipstat.ips_reassembled++; 958 ip = mtod(m, struct ip *); 959 hlen = ip->ip_hl << 2; 960 ip->ip_len = htons(ntohs(ip->ip_len) + hlen); 961 } else 962 if (fp) 963 ip_freef(fp); 964 IPQ_UNLOCK(); 965 } 966 967 #if defined(IPSEC) 968 /* 969 * enforce IPsec policy checking if we are seeing last header. 970 * note that we do not visit this with protocols with pcb layer 971 * code - like udp/tcp/raw ip. 972 */ 973 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 974 ipsec4_in_reject(m, NULL)) { 975 ipsecstat.in_polvio++; 976 goto bad; 977 } 978 #endif 979 #if FAST_IPSEC 980 /* 981 * enforce IPsec policy checking if we are seeing last header. 982 * note that we do not visit this with protocols with pcb layer 983 * code - like udp/tcp/raw ip. 984 */ 985 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 986 /* 987 * Check if the packet has already had IPsec processing 988 * done. If so, then just pass it along. This tag gets 989 * set during AH, ESP, etc. input handling, before the 990 * packet is returned to the ip input queue for delivery. 991 */ 992 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 993 s = splsoftnet(); 994 if (mtag != NULL) { 995 tdbi = (struct tdb_ident *)(mtag + 1); 996 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 997 } else { 998 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 999 IP_FORWARDING, &error); 1000 } 1001 if (sp != NULL) { 1002 /* 1003 * Check security policy against packet attributes. 1004 */ 1005 error = ipsec_in_reject(sp, m); 1006 KEY_FREESP(&sp); 1007 } else { 1008 /* XXX error stat??? */ 1009 error = EINVAL; 1010 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 1011 goto bad; 1012 } 1013 splx(s); 1014 if (error) 1015 goto bad; 1016 } 1017 #endif /* FAST_IPSEC */ 1018 1019 /* 1020 * Switch out to protocol's input routine. 1021 */ 1022 #if IFA_STATS 1023 if (ia && ip) 1024 ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len); 1025 #endif 1026 ipstat.ips_delivered++; 1027 { 1028 int off = hlen, nh = ip->ip_p; 1029 1030 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh); 1031 return; 1032 } 1033 bad: 1034 m_freem(m); 1035 return; 1036 1037 badcsum: 1038 ipstat.ips_badsum++; 1039 m_freem(m); 1040 } 1041 1042 /* 1043 * Take incoming datagram fragment and try to 1044 * reassemble it into whole datagram. If a chain for 1045 * reassembly of this datagram already exists, then it 1046 * is given as fp; otherwise have to make a chain. 1047 */ 1048 struct mbuf * 1049 ip_reass(ipqe, fp, ipqhead) 1050 struct ipqent *ipqe; 1051 struct ipq *fp; 1052 struct ipqhead *ipqhead; 1053 { 1054 struct mbuf *m = ipqe->ipqe_m; 1055 struct ipqent *nq, *p, *q; 1056 struct ip *ip; 1057 struct mbuf *t; 1058 int hlen = ipqe->ipqe_ip->ip_hl << 2; 1059 int i, next; 1060 1061 IPQ_LOCK_CHECK(); 1062 1063 /* 1064 * Presence of header sizes in mbufs 1065 * would confuse code below. 1066 */ 1067 m->m_data += hlen; 1068 m->m_len -= hlen; 1069 1070 #ifdef notyet 1071 /* make sure fragment limit is up-to-date */ 1072 CHECK_NMBCLUSTER_PARAMS(); 1073 1074 /* If we have too many fragments, drop the older half. */ 1075 if (ip_nfrags >= ip_maxfrags) 1076 ip_reass_drophalf(void); 1077 #endif 1078 1079 /* 1080 * We are about to add a fragment; increment frag count. 1081 */ 1082 ip_nfrags++; 1083 1084 /* 1085 * If first fragment to arrive, create a reassembly queue. 1086 */ 1087 if (fp == 0) { 1088 /* 1089 * Enforce upper bound on number of fragmented packets 1090 * for which we attempt reassembly; 1091 * If maxfrag is 0, never accept fragments. 1092 * If maxfrag is -1, accept all fragments without limitation. 1093 */ 1094 if (ip_maxfragpackets < 0) 1095 ; 1096 else if (ip_nfragpackets >= ip_maxfragpackets) 1097 goto dropfrag; 1098 ip_nfragpackets++; 1099 MALLOC(fp, struct ipq *, sizeof (struct ipq), 1100 M_FTABLE, M_NOWAIT); 1101 if (fp == NULL) 1102 goto dropfrag; 1103 LIST_INSERT_HEAD(ipqhead, fp, ipq_q); 1104 fp->ipq_nfrags = 1; 1105 fp->ipq_ttl = IPFRAGTTL; 1106 fp->ipq_p = ipqe->ipqe_ip->ip_p; 1107 fp->ipq_id = ipqe->ipqe_ip->ip_id; 1108 TAILQ_INIT(&fp->ipq_fragq); 1109 fp->ipq_src = ipqe->ipqe_ip->ip_src; 1110 fp->ipq_dst = ipqe->ipqe_ip->ip_dst; 1111 p = NULL; 1112 goto insert; 1113 } else { 1114 fp->ipq_nfrags++; 1115 } 1116 1117 /* 1118 * Find a segment which begins after this one does. 1119 */ 1120 for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; 1121 p = q, q = TAILQ_NEXT(q, ipqe_q)) 1122 if (ntohs(q->ipqe_ip->ip_off) > ntohs(ipqe->ipqe_ip->ip_off)) 1123 break; 1124 1125 /* 1126 * If there is a preceding segment, it may provide some of 1127 * our data already. If so, drop the data from the incoming 1128 * segment. If it provides all of our data, drop us. 1129 */ 1130 if (p != NULL) { 1131 i = ntohs(p->ipqe_ip->ip_off) + ntohs(p->ipqe_ip->ip_len) - 1132 ntohs(ipqe->ipqe_ip->ip_off); 1133 if (i > 0) { 1134 if (i >= ntohs(ipqe->ipqe_ip->ip_len)) 1135 goto dropfrag; 1136 m_adj(ipqe->ipqe_m, i); 1137 ipqe->ipqe_ip->ip_off = 1138 htons(ntohs(ipqe->ipqe_ip->ip_off) + i); 1139 ipqe->ipqe_ip->ip_len = 1140 htons(ntohs(ipqe->ipqe_ip->ip_len) - i); 1141 } 1142 } 1143 1144 /* 1145 * While we overlap succeeding segments trim them or, 1146 * if they are completely covered, dequeue them. 1147 */ 1148 for (; q != NULL && 1149 ntohs(ipqe->ipqe_ip->ip_off) + ntohs(ipqe->ipqe_ip->ip_len) > 1150 ntohs(q->ipqe_ip->ip_off); q = nq) { 1151 i = (ntohs(ipqe->ipqe_ip->ip_off) + 1152 ntohs(ipqe->ipqe_ip->ip_len)) - ntohs(q->ipqe_ip->ip_off); 1153 if (i < ntohs(q->ipqe_ip->ip_len)) { 1154 q->ipqe_ip->ip_len = 1155 htons(ntohs(q->ipqe_ip->ip_len) - i); 1156 q->ipqe_ip->ip_off = 1157 htons(ntohs(q->ipqe_ip->ip_off) + i); 1158 m_adj(q->ipqe_m, i); 1159 break; 1160 } 1161 nq = TAILQ_NEXT(q, ipqe_q); 1162 m_freem(q->ipqe_m); 1163 TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q); 1164 pool_put(&ipqent_pool, q); 1165 fp->ipq_nfrags--; 1166 ip_nfrags--; 1167 } 1168 1169 insert: 1170 /* 1171 * Stick new segment in its place; 1172 * check for complete reassembly. 1173 */ 1174 if (p == NULL) { 1175 TAILQ_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); 1176 } else { 1177 TAILQ_INSERT_AFTER(&fp->ipq_fragq, p, ipqe, ipqe_q); 1178 } 1179 next = 0; 1180 for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; 1181 p = q, q = TAILQ_NEXT(q, ipqe_q)) { 1182 if (ntohs(q->ipqe_ip->ip_off) != next) 1183 return (0); 1184 next += ntohs(q->ipqe_ip->ip_len); 1185 } 1186 if (p->ipqe_mff) 1187 return (0); 1188 1189 /* 1190 * Reassembly is complete. Check for a bogus message size and 1191 * concatenate fragments. 1192 */ 1193 q = TAILQ_FIRST(&fp->ipq_fragq); 1194 ip = q->ipqe_ip; 1195 if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) { 1196 ipstat.ips_toolong++; 1197 ip_freef(fp); 1198 return (0); 1199 } 1200 m = q->ipqe_m; 1201 t = m->m_next; 1202 m->m_next = 0; 1203 m_cat(m, t); 1204 nq = TAILQ_NEXT(q, ipqe_q); 1205 pool_put(&ipqent_pool, q); 1206 for (q = nq; q != NULL; q = nq) { 1207 t = q->ipqe_m; 1208 nq = TAILQ_NEXT(q, ipqe_q); 1209 pool_put(&ipqent_pool, q); 1210 m_cat(m, t); 1211 } 1212 ip_nfrags -= fp->ipq_nfrags; 1213 1214 /* 1215 * Create header for new ip packet by 1216 * modifying header of first packet; 1217 * dequeue and discard fragment reassembly header. 1218 * Make header visible. 1219 */ 1220 ip->ip_len = htons(next); 1221 ip->ip_src = fp->ipq_src; 1222 ip->ip_dst = fp->ipq_dst; 1223 LIST_REMOVE(fp, ipq_q); 1224 FREE(fp, M_FTABLE); 1225 ip_nfragpackets--; 1226 m->m_len += (ip->ip_hl << 2); 1227 m->m_data -= (ip->ip_hl << 2); 1228 /* some debugging cruft by sklower, below, will go away soon */ 1229 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1230 int plen = 0; 1231 for (t = m; t; t = t->m_next) 1232 plen += t->m_len; 1233 m->m_pkthdr.len = plen; 1234 } 1235 return (m); 1236 1237 dropfrag: 1238 if (fp != 0) 1239 fp->ipq_nfrags--; 1240 ip_nfrags--; 1241 ipstat.ips_fragdropped++; 1242 m_freem(m); 1243 pool_put(&ipqent_pool, ipqe); 1244 return (0); 1245 } 1246 1247 /* 1248 * Free a fragment reassembly header and all 1249 * associated datagrams. 1250 */ 1251 void 1252 ip_freef(fp) 1253 struct ipq *fp; 1254 { 1255 struct ipqent *q, *p; 1256 u_int nfrags = 0; 1257 1258 IPQ_LOCK_CHECK(); 1259 1260 for (q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; q = p) { 1261 p = TAILQ_NEXT(q, ipqe_q); 1262 m_freem(q->ipqe_m); 1263 nfrags++; 1264 TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q); 1265 pool_put(&ipqent_pool, q); 1266 } 1267 1268 if (nfrags != fp->ipq_nfrags) 1269 printf("ip_freef: nfrags %d != %d\n", fp->ipq_nfrags, nfrags); 1270 ip_nfrags -= nfrags; 1271 LIST_REMOVE(fp, ipq_q); 1272 FREE(fp, M_FTABLE); 1273 ip_nfragpackets--; 1274 } 1275 1276 /* 1277 * IP reassembly TTL machinery for multiplicative drop. 1278 */ 1279 static u_int fragttl_histo[(IPFRAGTTL+1)]; 1280 1281 1282 /* 1283 * Decrement TTL of all reasembly queue entries by `ticks'. 1284 * Count number of distinct fragments (as opposed to partial, fragmented 1285 * datagrams) in the reassembly queue. While we traverse the entire 1286 * reassembly queue, compute and return the median TTL over all fragments. 1287 */ 1288 static u_int 1289 ip_reass_ttl_decr(u_int ticks) 1290 { 1291 u_int i, nfrags, median; 1292 struct ipq *fp, *nfp; 1293 u_int dropfraction, keepfraction; 1294 1295 nfrags = 0; 1296 memset(fragttl_histo, 0, sizeof fragttl_histo); 1297 1298 for (i = 0; i < IPREASS_NHASH; i++) { 1299 for (fp = LIST_FIRST(&ipq[i]); fp != NULL; fp = nfp) { 1300 fp->ipq_ttl = ((fp->ipq_ttl <= ticks) ? 1301 0 : fp->ipq_ttl - ticks); 1302 nfp = LIST_NEXT(fp, ipq_q); 1303 if (fp->ipq_ttl == 0) { 1304 ipstat.ips_fragtimeout++; 1305 ip_freef(fp); 1306 } else { 1307 nfrags += fp->ipq_nfrags; 1308 fragttl_histo[fp->ipq_ttl] += fp->ipq_nfrags; 1309 } 1310 } 1311 } 1312 1313 KASSERT(ip_nfrags == nfrags); 1314 1315 /* Find median (or other drop fraction) in histogram. */ 1316 dropfraction = (ip_nfrags / 2); 1317 keepfraction = ip_nfrags - dropfraction; 1318 for (i = IPFRAGTTL, median = 0; i >= 0; i--) { 1319 median += fragttl_histo[i]; 1320 if (median >= keepfraction) 1321 break; 1322 } 1323 1324 /* Return TTL of median (or other fraction). */ 1325 return (u_int)i; 1326 } 1327 1328 void 1329 ip_reass_drophalf(void) 1330 { 1331 1332 u_int median_ticks; 1333 /* 1334 * Compute median TTL of all fragments, and count frags 1335 * with that TTL or lower (roughly half of all fragments). 1336 */ 1337 median_ticks = ip_reass_ttl_decr(0); 1338 1339 /* Drop half. */ 1340 median_ticks = ip_reass_ttl_decr(median_ticks); 1341 1342 } 1343 1344 /* 1345 * IP timer processing; 1346 * if a timer expires on a reassembly 1347 * queue, discard it. 1348 */ 1349 void 1350 ip_slowtimo() 1351 { 1352 static u_int dropscanidx = 0; 1353 u_int i; 1354 u_int median_ttl; 1355 int s = splsoftnet(); 1356 1357 IPQ_LOCK(); 1358 1359 /* Age TTL of all fragments by 1 tick .*/ 1360 median_ttl = ip_reass_ttl_decr(1); 1361 1362 /* make sure fragment limit is up-to-date */ 1363 CHECK_NMBCLUSTER_PARAMS(); 1364 1365 /* If we have too many fragments, drop the older half. */ 1366 if (ip_nfrags > ip_maxfrags) 1367 ip_reass_ttl_decr(median_ttl); 1368 1369 /* 1370 * If we are over the maximum number of fragmented packets 1371 * (due to the limit being lowered), drain off 1372 * enough to get down to the new limit. Start draining 1373 * from the reassembly hashqueue most recently drained. 1374 */ 1375 if (ip_maxfragpackets < 0) 1376 ; 1377 else { 1378 int wrapped = 0; 1379 1380 i = dropscanidx; 1381 while (ip_nfragpackets > ip_maxfragpackets && wrapped == 0) { 1382 while (LIST_FIRST(&ipq[i]) != NULL) 1383 ip_freef(LIST_FIRST(&ipq[i])); 1384 if (++i >= IPREASS_NHASH) { 1385 i = 0; 1386 } 1387 /* 1388 * Dont scan forever even if fragment counters are 1389 * wrong: stop after scanning entire reassembly queue. 1390 */ 1391 if (i == dropscanidx) 1392 wrapped = 1; 1393 } 1394 dropscanidx = i; 1395 } 1396 IPQ_UNLOCK(); 1397 #ifdef GATEWAY 1398 ipflow_slowtimo(); 1399 #endif 1400 splx(s); 1401 } 1402 1403 /* 1404 * Drain off all datagram fragments. 1405 */ 1406 void 1407 ip_drain() 1408 { 1409 1410 /* 1411 * We may be called from a device's interrupt context. If 1412 * the ipq is already busy, just bail out now. 1413 */ 1414 if (ipq_lock_try() == 0) 1415 return; 1416 1417 /* 1418 * Drop half the total fragments now. If more mbufs are needed, 1419 * we will be called again soon. 1420 */ 1421 ip_reass_drophalf(); 1422 1423 IPQ_UNLOCK(); 1424 } 1425 1426 /* 1427 * Do option processing on a datagram, 1428 * possibly discarding it if bad options are encountered, 1429 * or forwarding it if source-routed. 1430 * Returns 1 if packet has been forwarded/freed, 1431 * 0 if the packet should be processed further. 1432 */ 1433 int 1434 ip_dooptions(m) 1435 struct mbuf *m; 1436 { 1437 struct ip *ip = mtod(m, struct ip *); 1438 u_char *cp, *cp0; 1439 struct ip_timestamp *ipt; 1440 struct in_ifaddr *ia; 1441 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1442 struct in_addr dst; 1443 n_time ntime; 1444 1445 dst = ip->ip_dst; 1446 cp = (u_char *)(ip + 1); 1447 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1448 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1449 opt = cp[IPOPT_OPTVAL]; 1450 if (opt == IPOPT_EOL) 1451 break; 1452 if (opt == IPOPT_NOP) 1453 optlen = 1; 1454 else { 1455 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1456 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1457 goto bad; 1458 } 1459 optlen = cp[IPOPT_OLEN]; 1460 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1461 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1462 goto bad; 1463 } 1464 } 1465 switch (opt) { 1466 1467 default: 1468 break; 1469 1470 /* 1471 * Source routing with record. 1472 * Find interface with current destination address. 1473 * If none on this machine then drop if strictly routed, 1474 * or do nothing if loosely routed. 1475 * Record interface address and bring up next address 1476 * component. If strictly routed make sure next 1477 * address is on directly accessible net. 1478 */ 1479 case IPOPT_LSRR: 1480 case IPOPT_SSRR: 1481 if (ip_allowsrcrt == 0) { 1482 type = ICMP_UNREACH; 1483 code = ICMP_UNREACH_NET_PROHIB; 1484 goto bad; 1485 } 1486 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1487 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1488 goto bad; 1489 } 1490 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1491 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1492 goto bad; 1493 } 1494 ipaddr.sin_addr = ip->ip_dst; 1495 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); 1496 if (ia == 0) { 1497 if (opt == IPOPT_SSRR) { 1498 type = ICMP_UNREACH; 1499 code = ICMP_UNREACH_SRCFAIL; 1500 goto bad; 1501 } 1502 /* 1503 * Loose routing, and not at next destination 1504 * yet; nothing to do except forward. 1505 */ 1506 break; 1507 } 1508 off--; /* 0 origin */ 1509 if ((off + sizeof(struct in_addr)) > optlen) { 1510 /* 1511 * End of source route. Should be for us. 1512 */ 1513 save_rte(cp, ip->ip_src); 1514 break; 1515 } 1516 /* 1517 * locate outgoing interface 1518 */ 1519 bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr, 1520 sizeof(ipaddr.sin_addr)); 1521 if (opt == IPOPT_SSRR) 1522 ia = ifatoia(ifa_ifwithladdr(sintosa(&ipaddr))); 1523 else 1524 ia = ip_rtaddr(ipaddr.sin_addr); 1525 if (ia == 0) { 1526 type = ICMP_UNREACH; 1527 code = ICMP_UNREACH_SRCFAIL; 1528 goto bad; 1529 } 1530 ip->ip_dst = ipaddr.sin_addr; 1531 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1532 (caddr_t)(cp + off), sizeof(struct in_addr)); 1533 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1534 /* 1535 * Let ip_intr's mcast routing check handle mcast pkts 1536 */ 1537 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1538 break; 1539 1540 case IPOPT_RR: 1541 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1542 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1543 goto bad; 1544 } 1545 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1546 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1547 goto bad; 1548 } 1549 /* 1550 * If no space remains, ignore. 1551 */ 1552 off--; /* 0 origin */ 1553 if ((off + sizeof(struct in_addr)) > optlen) 1554 break; 1555 bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr, 1556 sizeof(ipaddr.sin_addr)); 1557 /* 1558 * locate outgoing interface; if we're the destination, 1559 * use the incoming interface (should be same). 1560 */ 1561 if ((ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)))) 1562 == NULL && 1563 (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) { 1564 type = ICMP_UNREACH; 1565 code = ICMP_UNREACH_HOST; 1566 goto bad; 1567 } 1568 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1569 (caddr_t)(cp + off), sizeof(struct in_addr)); 1570 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1571 break; 1572 1573 case IPOPT_TS: 1574 code = cp - (u_char *)ip; 1575 ipt = (struct ip_timestamp *)cp; 1576 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1577 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1578 goto bad; 1579 } 1580 if (ipt->ipt_ptr < 5) { 1581 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1582 goto bad; 1583 } 1584 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) { 1585 if (++ipt->ipt_oflw == 0) { 1586 code = (u_char *)&ipt->ipt_ptr - 1587 (u_char *)ip; 1588 goto bad; 1589 } 1590 break; 1591 } 1592 cp0 = (cp + ipt->ipt_ptr - 1); 1593 switch (ipt->ipt_flg) { 1594 1595 case IPOPT_TS_TSONLY: 1596 break; 1597 1598 case IPOPT_TS_TSANDADDR: 1599 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1600 sizeof(struct in_addr) > ipt->ipt_len) { 1601 code = (u_char *)&ipt->ipt_ptr - 1602 (u_char *)ip; 1603 goto bad; 1604 } 1605 ipaddr.sin_addr = dst; 1606 ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr), 1607 m->m_pkthdr.rcvif)); 1608 if (ia == 0) 1609 continue; 1610 bcopy(&ia->ia_addr.sin_addr, 1611 cp0, sizeof(struct in_addr)); 1612 ipt->ipt_ptr += sizeof(struct in_addr); 1613 break; 1614 1615 case IPOPT_TS_PRESPEC: 1616 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1617 sizeof(struct in_addr) > ipt->ipt_len) { 1618 code = (u_char *)&ipt->ipt_ptr - 1619 (u_char *)ip; 1620 goto bad; 1621 } 1622 bcopy(cp0, &ipaddr.sin_addr, 1623 sizeof(struct in_addr)); 1624 if (ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))) 1625 == NULL) 1626 continue; 1627 ipt->ipt_ptr += sizeof(struct in_addr); 1628 break; 1629 1630 default: 1631 /* XXX can't take &ipt->ipt_flg */ 1632 code = (u_char *)&ipt->ipt_ptr - 1633 (u_char *)ip + 1; 1634 goto bad; 1635 } 1636 ntime = iptime(); 1637 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */ 1638 bcopy(cp0, (caddr_t)cp + ipt->ipt_ptr - 1, 1639 sizeof(n_time)); 1640 ipt->ipt_ptr += sizeof(n_time); 1641 } 1642 } 1643 if (forward) { 1644 if (ip_forwsrcrt == 0) { 1645 type = ICMP_UNREACH; 1646 code = ICMP_UNREACH_SRCFAIL; 1647 goto bad; 1648 } 1649 ip_forward(m, 1); 1650 return (1); 1651 } 1652 return (0); 1653 bad: 1654 icmp_error(m, type, code, 0, 0); 1655 ipstat.ips_badoptions++; 1656 return (1); 1657 } 1658 1659 /* 1660 * Given address of next destination (final or next hop), 1661 * return internet address info of interface to be used to get there. 1662 */ 1663 struct in_ifaddr * 1664 ip_rtaddr(dst) 1665 struct in_addr dst; 1666 { 1667 struct sockaddr_in *sin; 1668 1669 sin = satosin(&ipforward_rt.ro_dst); 1670 1671 if (ipforward_rt.ro_rt == 0 || !in_hosteq(dst, sin->sin_addr)) { 1672 if (ipforward_rt.ro_rt) { 1673 RTFREE(ipforward_rt.ro_rt); 1674 ipforward_rt.ro_rt = 0; 1675 } 1676 sin->sin_family = AF_INET; 1677 sin->sin_len = sizeof(*sin); 1678 sin->sin_addr = dst; 1679 1680 rtalloc(&ipforward_rt); 1681 } 1682 if (ipforward_rt.ro_rt == 0) 1683 return ((struct in_ifaddr *)0); 1684 return (ifatoia(ipforward_rt.ro_rt->rt_ifa)); 1685 } 1686 1687 /* 1688 * Save incoming source route for use in replies, 1689 * to be picked up later by ip_srcroute if the receiver is interested. 1690 */ 1691 void 1692 save_rte(option, dst) 1693 u_char *option; 1694 struct in_addr dst; 1695 { 1696 unsigned olen; 1697 1698 olen = option[IPOPT_OLEN]; 1699 #ifdef DIAGNOSTIC 1700 if (ipprintfs) 1701 printf("save_rte: olen %d\n", olen); 1702 #endif /* 0 */ 1703 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1704 return; 1705 bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen); 1706 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1707 ip_srcrt.dst = dst; 1708 } 1709 1710 /* 1711 * Retrieve incoming source route for use in replies, 1712 * in the same form used by setsockopt. 1713 * The first hop is placed before the options, will be removed later. 1714 */ 1715 struct mbuf * 1716 ip_srcroute() 1717 { 1718 struct in_addr *p, *q; 1719 struct mbuf *m; 1720 1721 if (ip_nhops == 0) 1722 return ((struct mbuf *)0); 1723 m = m_get(M_DONTWAIT, MT_SOOPTS); 1724 if (m == 0) 1725 return ((struct mbuf *)0); 1726 1727 MCLAIM(m, &inetdomain.dom_mowner); 1728 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1729 1730 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1731 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1732 OPTSIZ; 1733 #ifdef DIAGNOSTIC 1734 if (ipprintfs) 1735 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1736 #endif 1737 1738 /* 1739 * First save first hop for return route 1740 */ 1741 p = &ip_srcrt.route[ip_nhops - 1]; 1742 *(mtod(m, struct in_addr *)) = *p--; 1743 #ifdef DIAGNOSTIC 1744 if (ipprintfs) 1745 printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1746 #endif 1747 1748 /* 1749 * Copy option fields and padding (nop) to mbuf. 1750 */ 1751 ip_srcrt.nop = IPOPT_NOP; 1752 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1753 bcopy((caddr_t)&ip_srcrt.nop, 1754 mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ); 1755 q = (struct in_addr *)(mtod(m, caddr_t) + 1756 sizeof(struct in_addr) + OPTSIZ); 1757 #undef OPTSIZ 1758 /* 1759 * Record return path as an IP source route, 1760 * reversing the path (pointers are now aligned). 1761 */ 1762 while (p >= ip_srcrt.route) { 1763 #ifdef DIAGNOSTIC 1764 if (ipprintfs) 1765 printf(" %x", ntohl(q->s_addr)); 1766 #endif 1767 *q++ = *p--; 1768 } 1769 /* 1770 * Last hop goes to final destination. 1771 */ 1772 *q = ip_srcrt.dst; 1773 #ifdef DIAGNOSTIC 1774 if (ipprintfs) 1775 printf(" %x\n", ntohl(q->s_addr)); 1776 #endif 1777 return (m); 1778 } 1779 1780 /* 1781 * Strip out IP options, at higher 1782 * level protocol in the kernel. 1783 * Second argument is buffer to which options 1784 * will be moved, and return value is their length. 1785 * XXX should be deleted; last arg currently ignored. 1786 */ 1787 void 1788 ip_stripoptions(m, mopt) 1789 struct mbuf *m; 1790 struct mbuf *mopt; 1791 { 1792 int i; 1793 struct ip *ip = mtod(m, struct ip *); 1794 caddr_t opts; 1795 int olen; 1796 1797 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1798 opts = (caddr_t)(ip + 1); 1799 i = m->m_len - (sizeof (struct ip) + olen); 1800 bcopy(opts + olen, opts, (unsigned)i); 1801 m->m_len -= olen; 1802 if (m->m_flags & M_PKTHDR) 1803 m->m_pkthdr.len -= olen; 1804 ip->ip_len = htons(ntohs(ip->ip_len) - olen); 1805 ip->ip_hl = sizeof (struct ip) >> 2; 1806 } 1807 1808 const int inetctlerrmap[PRC_NCMDS] = { 1809 0, 0, 0, 0, 1810 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1811 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1812 EMSGSIZE, EHOSTUNREACH, 0, 0, 1813 0, 0, 0, 0, 1814 ENOPROTOOPT 1815 }; 1816 1817 /* 1818 * Forward a packet. If some error occurs return the sender 1819 * an icmp packet. Note we can't always generate a meaningful 1820 * icmp message because icmp doesn't have a large enough repertoire 1821 * of codes and types. 1822 * 1823 * If not forwarding, just drop the packet. This could be confusing 1824 * if ipforwarding was zero but some routing protocol was advancing 1825 * us as a gateway to somewhere. However, we must let the routing 1826 * protocol deal with that. 1827 * 1828 * The srcrt parameter indicates whether the packet is being forwarded 1829 * via a source route. 1830 */ 1831 void 1832 ip_forward(m, srcrt) 1833 struct mbuf *m; 1834 int srcrt; 1835 { 1836 struct ip *ip = mtod(m, struct ip *); 1837 struct sockaddr_in *sin; 1838 struct rtentry *rt; 1839 int error, type = 0, code = 0; 1840 struct mbuf *mcopy; 1841 n_long dest; 1842 struct ifnet *destifp; 1843 #if defined(IPSEC) || defined(FAST_IPSEC) 1844 struct ifnet dummyifp; 1845 #endif 1846 1847 /* 1848 * We are now in the output path. 1849 */ 1850 MCLAIM(m, &ip_tx_mowner); 1851 1852 /* 1853 * Clear any in-bound checksum flags for this packet. 1854 */ 1855 m->m_pkthdr.csum_flags = 0; 1856 1857 dest = 0; 1858 #ifdef DIAGNOSTIC 1859 if (ipprintfs) 1860 printf("forward: src %2.2x dst %2.2x ttl %x\n", 1861 ntohl(ip->ip_src.s_addr), 1862 ntohl(ip->ip_dst.s_addr), ip->ip_ttl); 1863 #endif 1864 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1865 ipstat.ips_cantforward++; 1866 m_freem(m); 1867 return; 1868 } 1869 if (ip->ip_ttl <= IPTTLDEC) { 1870 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1871 return; 1872 } 1873 ip->ip_ttl -= IPTTLDEC; 1874 1875 sin = satosin(&ipforward_rt.ro_dst); 1876 if ((rt = ipforward_rt.ro_rt) == 0 || 1877 !in_hosteq(ip->ip_dst, sin->sin_addr)) { 1878 if (ipforward_rt.ro_rt) { 1879 RTFREE(ipforward_rt.ro_rt); 1880 ipforward_rt.ro_rt = 0; 1881 } 1882 sin->sin_family = AF_INET; 1883 sin->sin_len = sizeof(struct sockaddr_in); 1884 sin->sin_addr = ip->ip_dst; 1885 1886 rtalloc(&ipforward_rt); 1887 if (ipforward_rt.ro_rt == 0) { 1888 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1889 return; 1890 } 1891 rt = ipforward_rt.ro_rt; 1892 } 1893 1894 /* 1895 * Save at most 68 bytes of the packet in case 1896 * we need to generate an ICMP message to the src. 1897 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1898 */ 1899 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1900 if (mcopy) 1901 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1902 1903 /* 1904 * If forwarding packet using same interface that it came in on, 1905 * perhaps should send a redirect to sender to shortcut a hop. 1906 * Only send redirect if source is sending directly to us, 1907 * and if packet was not source routed (or has any options). 1908 * Also, don't send redirect if forwarding using a default route 1909 * or a route modified by a redirect. 1910 */ 1911 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1912 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1913 !in_nullhost(satosin(rt_key(rt))->sin_addr) && 1914 ipsendredirects && !srcrt) { 1915 if (rt->rt_ifa && 1916 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1917 ifatoia(rt->rt_ifa)->ia_subnet) { 1918 if (rt->rt_flags & RTF_GATEWAY) 1919 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1920 else 1921 dest = ip->ip_dst.s_addr; 1922 /* 1923 * Router requirements says to only send host 1924 * redirects. 1925 */ 1926 type = ICMP_REDIRECT; 1927 code = ICMP_REDIRECT_HOST; 1928 #ifdef DIAGNOSTIC 1929 if (ipprintfs) 1930 printf("redirect (%d) to %x\n", code, 1931 (u_int32_t)dest); 1932 #endif 1933 } 1934 } 1935 1936 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1937 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1938 (struct ip_moptions *)NULL, (struct socket *)NULL); 1939 1940 if (error) 1941 ipstat.ips_cantforward++; 1942 else { 1943 ipstat.ips_forward++; 1944 if (type) 1945 ipstat.ips_redirectsent++; 1946 else { 1947 if (mcopy) { 1948 #ifdef GATEWAY 1949 if (mcopy->m_flags & M_CANFASTFWD) 1950 ipflow_create(&ipforward_rt, mcopy); 1951 #endif 1952 m_freem(mcopy); 1953 } 1954 return; 1955 } 1956 } 1957 if (mcopy == NULL) 1958 return; 1959 destifp = NULL; 1960 1961 switch (error) { 1962 1963 case 0: /* forwarded, but need redirect */ 1964 /* type, code set above */ 1965 break; 1966 1967 case ENETUNREACH: /* shouldn't happen, checked above */ 1968 case EHOSTUNREACH: 1969 case ENETDOWN: 1970 case EHOSTDOWN: 1971 default: 1972 type = ICMP_UNREACH; 1973 code = ICMP_UNREACH_HOST; 1974 break; 1975 1976 case EMSGSIZE: 1977 type = ICMP_UNREACH; 1978 code = ICMP_UNREACH_NEEDFRAG; 1979 #if !defined(IPSEC) && !defined(FAST_IPSEC) 1980 if (ipforward_rt.ro_rt) 1981 destifp = ipforward_rt.ro_rt->rt_ifp; 1982 #else 1983 /* 1984 * If the packet is routed over IPsec tunnel, tell the 1985 * originator the tunnel MTU. 1986 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1987 * XXX quickhack!!! 1988 */ 1989 if (ipforward_rt.ro_rt) { 1990 struct secpolicy *sp; 1991 int ipsecerror; 1992 size_t ipsechdr; 1993 struct route *ro; 1994 1995 sp = ipsec4_getpolicybyaddr(mcopy, 1996 IPSEC_DIR_OUTBOUND, IP_FORWARDING, 1997 &ipsecerror); 1998 1999 if (sp == NULL) 2000 destifp = ipforward_rt.ro_rt->rt_ifp; 2001 else { 2002 /* count IPsec header size */ 2003 ipsechdr = ipsec4_hdrsiz(mcopy, 2004 IPSEC_DIR_OUTBOUND, NULL); 2005 2006 /* 2007 * find the correct route for outer IPv4 2008 * header, compute tunnel MTU. 2009 * 2010 * XXX BUG ALERT 2011 * The "dummyifp" code relies upon the fact 2012 * that icmp_error() touches only ifp->if_mtu. 2013 */ 2014 /*XXX*/ 2015 destifp = NULL; 2016 if (sp->req != NULL 2017 && sp->req->sav != NULL 2018 && sp->req->sav->sah != NULL) { 2019 ro = &sp->req->sav->sah->sa_route; 2020 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 2021 dummyifp.if_mtu = 2022 ro->ro_rt->rt_rmx.rmx_mtu ? 2023 ro->ro_rt->rt_rmx.rmx_mtu : 2024 ro->ro_rt->rt_ifp->if_mtu; 2025 dummyifp.if_mtu -= ipsechdr; 2026 destifp = &dummyifp; 2027 } 2028 } 2029 2030 #ifdef IPSEC 2031 key_freesp(sp); 2032 #else 2033 KEY_FREESP(&sp); 2034 #endif 2035 } 2036 } 2037 #endif /*IPSEC*/ 2038 ipstat.ips_cantfrag++; 2039 break; 2040 2041 case ENOBUFS: 2042 #if 1 2043 /* 2044 * a router should not generate ICMP_SOURCEQUENCH as 2045 * required in RFC1812 Requirements for IP Version 4 Routers. 2046 * source quench could be a big problem under DoS attacks, 2047 * or if the underlying interface is rate-limited. 2048 */ 2049 if (mcopy) 2050 m_freem(mcopy); 2051 return; 2052 #else 2053 type = ICMP_SOURCEQUENCH; 2054 code = 0; 2055 break; 2056 #endif 2057 } 2058 icmp_error(mcopy, type, code, dest, destifp); 2059 } 2060 2061 void 2062 ip_savecontrol(inp, mp, ip, m) 2063 struct inpcb *inp; 2064 struct mbuf **mp; 2065 struct ip *ip; 2066 struct mbuf *m; 2067 { 2068 2069 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2070 struct timeval tv; 2071 2072 microtime(&tv); 2073 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2074 SCM_TIMESTAMP, SOL_SOCKET); 2075 if (*mp) 2076 mp = &(*mp)->m_next; 2077 } 2078 if (inp->inp_flags & INP_RECVDSTADDR) { 2079 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2080 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2081 if (*mp) 2082 mp = &(*mp)->m_next; 2083 } 2084 #ifdef notyet 2085 /* 2086 * XXX 2087 * Moving these out of udp_input() made them even more broken 2088 * than they already were. 2089 * - fenner@parc.xerox.com 2090 */ 2091 /* options were tossed already */ 2092 if (inp->inp_flags & INP_RECVOPTS) { 2093 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2094 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2095 if (*mp) 2096 mp = &(*mp)->m_next; 2097 } 2098 /* ip_srcroute doesn't do what we want here, need to fix */ 2099 if (inp->inp_flags & INP_RECVRETOPTS) { 2100 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2101 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2102 if (*mp) 2103 mp = &(*mp)->m_next; 2104 } 2105 #endif 2106 if (inp->inp_flags & INP_RECVIF) { 2107 struct sockaddr_dl sdl; 2108 2109 sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]); 2110 sdl.sdl_family = AF_LINK; 2111 sdl.sdl_index = m->m_pkthdr.rcvif ? 2112 m->m_pkthdr.rcvif->if_index : 0; 2113 sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0; 2114 *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len, 2115 IP_RECVIF, IPPROTO_IP); 2116 if (*mp) 2117 mp = &(*mp)->m_next; 2118 } 2119 } 2120 2121 /* 2122 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the 2123 * range of the new value and tweaks timers if it changes. 2124 */ 2125 static int 2126 sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS) 2127 { 2128 int error, tmp; 2129 struct sysctlnode node; 2130 2131 node = *rnode; 2132 tmp = ip_mtudisc_timeout; 2133 node.sysctl_data = &tmp; 2134 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 2135 if (error || newp == NULL) 2136 return (error); 2137 if (tmp < 0) 2138 return (EINVAL); 2139 2140 ip_mtudisc_timeout = tmp; 2141 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout); 2142 2143 return (0); 2144 } 2145 2146 #ifdef GATEWAY 2147 /* 2148 * sysctl helper routine for net.inet.ip.maxflows. apparently if 2149 * maxflows is even looked up, we "reap flows". 2150 */ 2151 static int 2152 sysctl_net_inet_ip_maxflows(SYSCTLFN_ARGS) 2153 { 2154 int s; 2155 2156 s = sysctl_lookup(SYSCTLFN_CALL(rnode)); 2157 if (s) 2158 return (s); 2159 2160 s = splsoftnet(); 2161 ipflow_reap(0); 2162 splx(s); 2163 2164 return (0); 2165 } 2166 #endif /* GATEWAY */ 2167 2168 2169 SYSCTL_SETUP(sysctl_net_inet_ip_setup, "sysctl net.inet.ip subtree setup") 2170 { 2171 extern int subnetsarelocal, hostzeroisbroadcast; 2172 2173 sysctl_createv(SYSCTL_PERMANENT, 2174 CTLTYPE_NODE, "net", NULL, 2175 NULL, 0, NULL, 0, 2176 CTL_NET, CTL_EOL); 2177 sysctl_createv(SYSCTL_PERMANENT, 2178 CTLTYPE_NODE, "inet", NULL, 2179 NULL, 0, NULL, 0, 2180 CTL_NET, PF_INET, CTL_EOL); 2181 sysctl_createv(SYSCTL_PERMANENT, 2182 CTLTYPE_NODE, "ip", NULL, 2183 NULL, 0, NULL, 0, 2184 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL); 2185 2186 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2187 CTLTYPE_INT, "forwarding", NULL, 2188 NULL, 0, &ipforwarding, 0, 2189 CTL_NET, PF_INET, IPPROTO_IP, 2190 IPCTL_FORWARDING, CTL_EOL); 2191 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2192 CTLTYPE_INT, "redirect", NULL, 2193 NULL, 0, &ipsendredirects, 0, 2194 CTL_NET, PF_INET, IPPROTO_IP, 2195 IPCTL_SENDREDIRECTS, CTL_EOL); 2196 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2197 CTLTYPE_INT, "ttl", NULL, 2198 NULL, 0, &ip_defttl, 0, 2199 CTL_NET, PF_INET, IPPROTO_IP, 2200 IPCTL_DEFTTL, CTL_EOL); 2201 #ifdef IPCTL_DEFMTU 2202 sysctl_createv(SYSCTL_PERMANENT /* |SYSCTL_READWRITE? */, 2203 CTLTYPE_INT, "mtu", NULL, 2204 NULL, 0, &ip_mtu, 0, 2205 CTL_NET, PF_INET, IPPROTO_IP, 2206 IPCTL_DEFMTU, CTL_EOL); 2207 #endif /* IPCTL_DEFMTU */ 2208 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READONLY1, 2209 CTLTYPE_INT, "forwsrcrt", NULL, 2210 NULL, 0, &ip_forwsrcrt, 0, 2211 CTL_NET, PF_INET, IPPROTO_IP, 2212 IPCTL_FORWSRCRT, CTL_EOL); 2213 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2214 CTLTYPE_INT, "directed-broadcast", NULL, 2215 NULL, 0, &ip_directedbcast, 0, 2216 CTL_NET, PF_INET, IPPROTO_IP, 2217 IPCTL_DIRECTEDBCAST, CTL_EOL); 2218 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2219 CTLTYPE_INT, "allowsrcrt", NULL, 2220 NULL, 0, &ip_allowsrcrt, 0, 2221 CTL_NET, PF_INET, IPPROTO_IP, 2222 IPCTL_ALLOWSRCRT, CTL_EOL); 2223 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2224 CTLTYPE_INT, "subnetsarelocal", NULL, 2225 NULL, 0, &subnetsarelocal, 0, 2226 CTL_NET, PF_INET, IPPROTO_IP, 2227 IPCTL_SUBNETSARELOCAL, CTL_EOL); 2228 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2229 CTLTYPE_INT, "mtudisc", NULL, 2230 NULL, 0, &ip_mtudisc, 0, 2231 CTL_NET, PF_INET, IPPROTO_IP, 2232 IPCTL_MTUDISC, CTL_EOL); 2233 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2234 CTLTYPE_INT, "anonportmin", NULL, 2235 sysctl_net_inet_ip_ports, 0, &anonportmin, 0, 2236 CTL_NET, PF_INET, IPPROTO_IP, 2237 IPCTL_ANONPORTMIN, CTL_EOL); 2238 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2239 CTLTYPE_INT, "anonportmax", NULL, 2240 sysctl_net_inet_ip_ports, 0, &anonportmax, 0, 2241 CTL_NET, PF_INET, IPPROTO_IP, 2242 IPCTL_ANONPORTMAX, CTL_EOL); 2243 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2244 CTLTYPE_INT, "mtudisctimeout", NULL, 2245 sysctl_net_inet_ip_pmtudto, 0, &ip_mtudisc_timeout, 0, 2246 CTL_NET, PF_INET, IPPROTO_IP, 2247 IPCTL_MTUDISCTIMEOUT, CTL_EOL); 2248 #ifdef GATEWAY 2249 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2250 CTLTYPE_INT, "maxflows", NULL, 2251 sysctl_net_inet_ip_maxflows, 0, &ip_maxflows, 0, 2252 CTL_NET, PF_INET, IPPROTO_IP, 2253 IPCTL_MAXFLOWS, CTL_EOL); 2254 #endif /* GATEWAY */ 2255 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2256 CTLTYPE_INT, "hostzerobroadcast", NULL, 2257 NULL, 0, &hostzeroisbroadcast, 0, 2258 CTL_NET, PF_INET, IPPROTO_IP, 2259 IPCTL_HOSTZEROBROADCAST, CTL_EOL); 2260 #if NGIF > 0 2261 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2262 CTLTYPE_INT, "gifttl", NULL, 2263 NULL, 0, &ip_gif_ttl, 0, 2264 CTL_NET, PF_INET, IPPROTO_IP, 2265 IPCTL_GIF_TTL, CTL_EOL); 2266 #endif /* NGIF */ 2267 #ifndef IPNOPRIVPORTS 2268 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2269 CTLTYPE_INT, "lowportmin", NULL, 2270 sysctl_net_inet_ip_ports, 0, &lowportmin, 0, 2271 CTL_NET, PF_INET, IPPROTO_IP, 2272 IPCTL_LOWPORTMIN, CTL_EOL); 2273 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2274 CTLTYPE_INT, "lowportmax", NULL, 2275 sysctl_net_inet_ip_ports, 0, &lowportmax, 0, 2276 CTL_NET, PF_INET, IPPROTO_IP, 2277 IPCTL_LOWPORTMAX, CTL_EOL); 2278 #endif /* IPNOPRIVPORTS */ 2279 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2280 CTLTYPE_INT, "maxfragpackets", NULL, 2281 NULL, 0, &ip_maxfragpackets, 0, 2282 CTL_NET, PF_INET, IPPROTO_IP, 2283 IPCTL_MAXFRAGPACKETS, CTL_EOL); 2284 #if NGRE > 0 2285 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2286 CTLTYPE_INT, "grettl", NULL, 2287 NULL, 0, &ip_gre_ttl, 0, 2288 CTL_NET, PF_INET, IPPROTO_IP, 2289 IPCTL_GRE_TTL, CTL_EOL); 2290 #endif /* NGRE */ 2291 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2292 CTLTYPE_INT, "checkinterface", NULL, 2293 NULL, 0, &ip_checkinterface, 0, 2294 CTL_NET, PF_INET, IPPROTO_IP, 2295 IPCTL_CHECKINTERFACE, CTL_EOL); 2296 sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE, 2297 CTLTYPE_INT, "random_id", NULL, 2298 NULL, 0, &ip_do_randomid, 0, 2299 CTL_NET, PF_INET, IPPROTO_IP, 2300 IPCTL_RANDOMID, CTL_EOL); 2301 } 2302