1 /* 2 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved. 3 * Copyright (c) 2003, 2004 The DragonFly Project. All rights reserved. 4 * 5 * This code is derived from software contributed to The DragonFly Project 6 * by Jeffrey M. Hsu. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of The DragonFly Project nor the names of its 17 * contributors may be used to endorse or promote products derived 18 * from this software without specific, prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright (c) 1982, 1986, 1988, 1993 36 * The Regents of the University of California. All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. Neither the name of the University nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 60 * SUCH DAMAGE. 61 * 62 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 63 * $FreeBSD: src/sys/netinet/ip_input.c,v 1.130.2.52 2003/03/07 07:01:28 silby Exp $ 64 */ 65 66 #define _IP_VHL 67 68 #include "opt_bootp.h" 69 #include "opt_ipdn.h" 70 #include "opt_ipdivert.h" 71 #include "opt_ipstealth.h" 72 #include "opt_ipsec.h" 73 #include "opt_rss.h" 74 75 #include <sys/param.h> 76 #include <sys/systm.h> 77 #include <sys/mbuf.h> 78 #include <sys/malloc.h> 79 #include <sys/mpipe.h> 80 #include <sys/domain.h> 81 #include <sys/protosw.h> 82 #include <sys/socket.h> 83 #include <sys/time.h> 84 #include <sys/globaldata.h> 85 #include <sys/thread.h> 86 #include <sys/kernel.h> 87 #include <sys/syslog.h> 88 #include <sys/sysctl.h> 89 #include <sys/in_cksum.h> 90 #include <sys/lock.h> 91 92 #include <sys/mplock2.h> 93 94 #include <machine/stdarg.h> 95 96 #include <net/if.h> 97 #include <net/if_types.h> 98 #include <net/if_var.h> 99 #include <net/if_dl.h> 100 #include <net/pfil.h> 101 #include <net/route.h> 102 #include <net/netisr2.h> 103 104 #include <netinet/in.h> 105 #include <netinet/in_systm.h> 106 #include <netinet/in_var.h> 107 #include <netinet/ip.h> 108 #include <netinet/in_pcb.h> 109 #include <netinet/ip_var.h> 110 #include <netinet/ip_icmp.h> 111 #include <netinet/ip_divert.h> 112 #include <netinet/ip_flow.h> 113 114 #include <sys/thread2.h> 115 #include <sys/msgport2.h> 116 #include <net/netmsg2.h> 117 118 #include <sys/socketvar.h> 119 120 #include <net/ipfw/ip_fw.h> 121 #include <net/dummynet/ip_dummynet.h> 122 123 #ifdef IPSEC 124 #include <netinet6/ipsec.h> 125 #include <netproto/key/key.h> 126 #endif 127 128 #ifdef FAST_IPSEC 129 #include <netproto/ipsec/ipsec.h> 130 #include <netproto/ipsec/key.h> 131 #endif 132 133 int rsvp_on = 0; 134 static int ip_rsvp_on; 135 struct socket *ip_rsvpd; 136 137 int ipforwarding = 0; 138 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 139 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 140 141 static int ipsendredirects = 1; /* XXX */ 142 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 143 &ipsendredirects, 0, "Enable sending IP redirects"); 144 145 int ip_defttl = IPDEFTTL; 146 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 147 &ip_defttl, 0, "Maximum TTL on IP packets"); 148 149 static int ip_dosourceroute = 0; 150 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 151 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 152 153 static int ip_acceptsourceroute = 0; 154 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 155 CTLFLAG_RW, &ip_acceptsourceroute, 0, 156 "Enable accepting source routed IP packets"); 157 158 static int ip_keepfaith = 0; 159 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 160 &ip_keepfaith, 0, 161 "Enable packet capture for FAITH IPv4->IPv6 translator daemon"); 162 163 static int nipq = 0; /* total # of reass queues */ 164 static int maxnipq; 165 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 166 &maxnipq, 0, 167 "Maximum number of IPv4 fragment reassembly queue entries"); 168 169 static int maxfragsperpacket; 170 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 171 &maxfragsperpacket, 0, 172 "Maximum number of IPv4 fragments allowed per packet"); 173 174 static int ip_sendsourcequench = 0; 175 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 176 &ip_sendsourcequench, 0, 177 "Enable the transmission of source quench packets"); 178 179 int ip_do_randomid = 1; 180 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 181 &ip_do_randomid, 0, 182 "Assign random ip_id values"); 183 /* 184 * XXX - Setting ip_checkinterface mostly implements the receive side of 185 * the Strong ES model described in RFC 1122, but since the routing table 186 * and transmit implementation do not implement the Strong ES model, 187 * setting this to 1 results in an odd hybrid. 188 * 189 * XXX - ip_checkinterface currently must be disabled if you use ipnat 190 * to translate the destination address to another local interface. 191 * 192 * XXX - ip_checkinterface must be disabled if you add IP aliases 193 * to the loopback interface instead of the interface where the 194 * packets for those addresses are received. 195 */ 196 static int ip_checkinterface = 0; 197 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 198 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 199 200 static u_long ip_hash_count = 0; 201 SYSCTL_ULONG(_net_inet_ip, OID_AUTO, hash_count, CTLFLAG_RD, 202 &ip_hash_count, 0, "Number of packets hashed by IP"); 203 204 #ifdef RSS_DEBUG 205 static u_long ip_rehash_count = 0; 206 SYSCTL_ULONG(_net_inet_ip, OID_AUTO, rehash_count, CTLFLAG_RD, 207 &ip_rehash_count, 0, "Number of packets rehashed by IP"); 208 209 static u_long ip_dispatch_fast = 0; 210 SYSCTL_ULONG(_net_inet_ip, OID_AUTO, dispatch_fast_count, CTLFLAG_RD, 211 &ip_dispatch_fast, 0, "Number of packets handled on current CPU"); 212 213 static u_long ip_dispatch_slow = 0; 214 SYSCTL_ULONG(_net_inet_ip, OID_AUTO, dispatch_slow_count, CTLFLAG_RD, 215 &ip_dispatch_slow, 0, "Number of packets messaged to another CPU"); 216 #endif 217 218 static struct lwkt_token ipq_token = LWKT_TOKEN_INITIALIZER(ipq_token); 219 220 #ifdef DIAGNOSTIC 221 static int ipprintfs = 0; 222 #endif 223 224 extern struct domain inetdomain; 225 extern struct protosw inetsw[]; 226 u_char ip_protox[IPPROTO_MAX]; 227 struct in_ifaddrhead in_ifaddrheads[MAXCPU]; /* first inet address */ 228 struct in_ifaddrhashhead *in_ifaddrhashtbls[MAXCPU]; 229 /* inet addr hash table */ 230 u_long in_ifaddrhmask; /* mask for hash table */ 231 232 static struct mbuf *ipforward_mtemp[MAXCPU]; 233 234 struct ip_stats ipstats_percpu[MAXCPU] __cachealign; 235 236 static int 237 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 238 { 239 int cpu, error = 0; 240 241 for (cpu = 0; cpu < ncpus; ++cpu) { 242 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu], 243 sizeof(struct ip_stats)))) 244 break; 245 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu], 246 sizeof(struct ip_stats)))) 247 break; 248 } 249 250 return (error); 251 } 252 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 253 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 254 255 /* Packet reassembly stuff */ 256 #define IPREASS_NHASH_LOG2 6 257 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 258 #define IPREASS_HMASK (IPREASS_NHASH - 1) 259 #define IPREASS_HASH(x,y) \ 260 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 261 262 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 263 264 #ifdef IPCTL_DEFMTU 265 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 266 &ip_mtu, 0, "Default MTU"); 267 #endif 268 269 #ifdef IPSTEALTH 270 static int ipstealth = 0; 271 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, ""); 272 #else 273 static const int ipstealth = 0; 274 #endif 275 276 struct mbuf *(*ip_divert_p)(struct mbuf *, int, int); 277 278 struct pfil_head inet_pfil_hook; 279 280 /* 281 * struct ip_srcrt_opt is used to store packet state while it travels 282 * through the stack. 283 * 284 * XXX Note that the code even makes assumptions on the size and 285 * alignment of fields inside struct ip_srcrt so e.g. adding some 286 * fields will break the code. This needs to be fixed. 287 * 288 * We need to save the IP options in case a protocol wants to respond 289 * to an incoming packet over the same route if the packet got here 290 * using IP source routing. This allows connection establishment and 291 * maintenance when the remote end is on a network that is not known 292 * to us. 293 */ 294 struct ip_srcrt { 295 struct in_addr dst; /* final destination */ 296 char nop; /* one NOP to align */ 297 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 298 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 299 }; 300 301 struct ip_srcrt_opt { 302 int ip_nhops; 303 struct ip_srcrt ip_srcrt; 304 }; 305 306 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 307 static struct malloc_pipe ipq_mpipe; 308 309 static void save_rte(struct mbuf *, u_char *, struct in_addr); 310 static int ip_dooptions(struct mbuf *m, int, struct sockaddr_in *); 311 static void ip_freef(struct ipqhead *, struct ipq *); 312 static void ip_input_handler(netmsg_t); 313 314 /* 315 * IP initialization: fill in IP protocol switch table. 316 * All protocols not implemented in kernel go to raw IP protocol handler. 317 */ 318 void 319 ip_init(void) 320 { 321 struct protosw *pr; 322 int i; 323 int cpu; 324 325 /* 326 * Make sure we can handle a reasonable number of fragments but 327 * cap it at 4000 (XXX). 328 */ 329 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 330 IFQ_MAXLEN, 4000, 0, NULL, NULL, NULL); 331 for (i = 0; i < ncpus; ++i) { 332 TAILQ_INIT(&in_ifaddrheads[i]); 333 in_ifaddrhashtbls[i] = 334 hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 335 } 336 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 337 if (pr == NULL) 338 panic("ip_init"); 339 for (i = 0; i < IPPROTO_MAX; i++) 340 ip_protox[i] = pr - inetsw; 341 for (pr = inetdomain.dom_protosw; 342 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 343 if (pr->pr_domain->dom_family == PF_INET && pr->pr_protocol) { 344 if (pr->pr_protocol != IPPROTO_RAW) 345 ip_protox[pr->pr_protocol] = pr - inetsw; 346 } 347 } 348 349 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 350 inet_pfil_hook.ph_af = AF_INET; 351 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) { 352 kprintf("%s: WARNING: unable to register pfil hook, " 353 "error %d\n", __func__, i); 354 } 355 356 for (i = 0; i < IPREASS_NHASH; i++) 357 TAILQ_INIT(&ipq[i]); 358 359 maxnipq = nmbclusters / 32; 360 maxfragsperpacket = 16; 361 362 ip_id = time_second & 0xffff; /* time_second survives reboots */ 363 364 for (cpu = 0; cpu < ncpus; ++cpu) { 365 /* 366 * Initialize IP statistics counters for each CPU. 367 */ 368 bzero(&ipstats_percpu[cpu], sizeof(struct ip_stats)); 369 370 /* 371 * Preallocate mbuf template for forwarding 372 */ 373 MGETHDR(ipforward_mtemp[cpu], MB_WAIT, MT_DATA); 374 } 375 376 netisr_register(NETISR_IP, ip_input_handler, ip_hashfn_in); 377 netisr_register_hashcheck(NETISR_IP, ip_hashcheck); 378 } 379 380 /* Do transport protocol processing. */ 381 static void 382 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip) 383 { 384 const struct protosw *pr = &inetsw[ip_protox[ip->ip_p]]; 385 386 /* 387 * Switch out to protocol's input routine. 388 */ 389 PR_GET_MPLOCK(pr); 390 pr->pr_input(&m, &hlen, ip->ip_p); 391 PR_REL_MPLOCK(pr); 392 } 393 394 static void 395 transport_processing_handler(netmsg_t msg) 396 { 397 struct netmsg_packet *pmsg = &msg->packet; 398 struct ip *ip; 399 int hlen; 400 401 ip = mtod(pmsg->nm_packet, struct ip *); 402 hlen = pmsg->base.lmsg.u.ms_result; 403 404 transport_processing_oncpu(pmsg->nm_packet, hlen, ip); 405 /* msg was embedded in the mbuf, do not reply! */ 406 } 407 408 static void 409 ip_input_handler(netmsg_t msg) 410 { 411 ip_input(msg->packet.nm_packet); 412 /* msg was embedded in the mbuf, do not reply! */ 413 } 414 415 /* 416 * IP input routine. Checksum and byte swap header. If fragmented 417 * try to reassemble. Process options. Pass to next level. 418 */ 419 void 420 ip_input(struct mbuf *m) 421 { 422 struct ip *ip; 423 struct in_ifaddr *ia = NULL; 424 struct in_ifaddr_container *iac; 425 int hlen, checkif; 426 u_short sum; 427 struct in_addr pkt_dst; 428 boolean_t check_msgport = FALSE; 429 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 430 struct in_addr odst; /* original dst address(NAT) */ 431 struct m_tag *mtag; 432 struct sockaddr_in *next_hop = NULL; 433 lwkt_port_t port; 434 #ifdef FAST_IPSEC 435 struct tdb_ident *tdbi; 436 struct secpolicy *sp; 437 int error; 438 #endif 439 440 M_ASSERTPKTHDR(m); 441 442 /* 443 * This routine is called from numerous places which may not have 444 * characterized the packet. 445 */ 446 if ((m->m_flags & M_HASH) == 0) { 447 atomic_add_long(&ip_hash_count, 1); 448 ip_hashfn(&m, 0, IP_MPORT_IN); 449 if (m == NULL) 450 return; 451 KKASSERT(m->m_flags & M_HASH); 452 check_msgport = TRUE; 453 } 454 ip = mtod(m, struct ip *); 455 456 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) || 457 ntohs(ip->ip_off) & (IP_MF | IP_OFFMASK)) { 458 /* 459 * XXX handle multicast and fragment on CPU0 for now. 460 * 461 * This could happen for IP packets hashed by hardwares 462 * using RSS: 463 * - Hardware may not differentiate multicast IP packets 464 * from unicast IP packets. 465 * - Hardware may not differentiate IP fragments from 466 * unfragmented IP packets. 467 */ 468 m->m_pkthdr.hash = 0; 469 check_msgport = TRUE; 470 } 471 472 if (check_msgport && 473 &curthread->td_msgport != netisr_hashport(m->m_pkthdr.hash)) { 474 netisr_queue(NETISR_IP, m); 475 /* Requeued to other netisr msgport; done */ 476 return; 477 } 478 479 /* 480 * Pull out certain tags 481 */ 482 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 483 /* Next hop */ 484 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 485 KKASSERT(mtag != NULL); 486 next_hop = m_tag_data(mtag); 487 } 488 489 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 490 /* dummynet already filtered us */ 491 ip = mtod(m, struct ip *); 492 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 493 goto iphack; 494 } 495 496 ipstat.ips_total++; 497 498 /* length checks already done in ip_hashfn() */ 499 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); 500 501 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 502 ipstat.ips_badvers++; 503 goto bad; 504 } 505 506 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 507 /* length checks already done in ip_hashfn() */ 508 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 509 KASSERT(m->m_len >= hlen, ("complete IP header not in one mbuf")); 510 511 /* 127/8 must not appear on wire - RFC1122 */ 512 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 513 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 514 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 515 ipstat.ips_badaddr++; 516 goto bad; 517 } 518 } 519 520 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 521 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 522 } else { 523 if (hlen == sizeof(struct ip)) 524 sum = in_cksum_hdr(ip); 525 else 526 sum = in_cksum(m, hlen); 527 } 528 if (sum != 0) { 529 ipstat.ips_badsum++; 530 goto bad; 531 } 532 533 #ifdef ALTQ 534 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 535 /* packet is dropped by traffic conditioner */ 536 return; 537 } 538 #endif 539 /* 540 * Convert fields to host representation. 541 */ 542 ip->ip_len = ntohs(ip->ip_len); 543 ip->ip_off = ntohs(ip->ip_off); 544 545 /* length checks already done in ip_hashfn() */ 546 KASSERT(ip->ip_len >= hlen, ("total length less then header length")); 547 KASSERT(m->m_pkthdr.len >= ip->ip_len, ("mbuf too short")); 548 549 /* 550 * Trim mbufs if longer than the IP header would have us expect. 551 */ 552 if (m->m_pkthdr.len > ip->ip_len) { 553 if (m->m_len == m->m_pkthdr.len) { 554 m->m_len = ip->ip_len; 555 m->m_pkthdr.len = ip->ip_len; 556 } else { 557 m_adj(m, ip->ip_len - m->m_pkthdr.len); 558 } 559 } 560 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 561 /* 562 * Bypass packet filtering for packets from a tunnel (gif). 563 */ 564 if (ipsec_gethist(m, NULL)) 565 goto pass; 566 #endif 567 568 /* 569 * IpHack's section. 570 * Right now when no processing on packet has done 571 * and it is still fresh out of network we do our black 572 * deals with it. 573 * - Firewall: deny/allow/divert 574 * - Xlate: translate packet's addr/port (NAT). 575 * - Pipe: pass pkt through dummynet. 576 * - Wrap: fake packet's addr/port <unimpl.> 577 * - Encapsulate: put it in another IP and send out. <unimp.> 578 */ 579 580 iphack: 581 /* 582 * If we've been forwarded from the output side, then 583 * skip the firewall a second time 584 */ 585 if (next_hop != NULL) 586 goto ours; 587 588 /* No pfil hooks */ 589 if (!pfil_has_hooks(&inet_pfil_hook)) { 590 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 591 /* 592 * Strip dummynet tags from stranded packets 593 */ 594 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL); 595 KKASSERT(mtag != NULL); 596 m_tag_delete(m, mtag); 597 m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED; 598 } 599 goto pass; 600 } 601 602 /* 603 * Run through list of hooks for input packets. 604 * 605 * NOTE! If the packet is rewritten pf/ipfw/whoever must 606 * clear M_HASH. 607 */ 608 odst = ip->ip_dst; 609 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN)) 610 return; 611 if (m == NULL) /* consumed by filter */ 612 return; 613 ip = mtod(m, struct ip *); 614 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 615 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 616 617 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 618 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 619 KKASSERT(mtag != NULL); 620 next_hop = m_tag_data(mtag); 621 } 622 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 623 ip_dn_queue(m); 624 return; 625 } 626 if (m->m_pkthdr.fw_flags & FW_MBUF_REDISPATCH) { 627 m->m_pkthdr.fw_flags &= ~FW_MBUF_REDISPATCH; 628 } 629 pass: 630 /* 631 * Process options and, if not destined for us, 632 * ship it on. ip_dooptions returns 1 when an 633 * error was detected (causing an icmp message 634 * to be sent and the original packet to be freed). 635 */ 636 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, next_hop)) 637 return; 638 639 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 640 * matter if it is destined to another node, or whether it is 641 * a multicast one, RSVP wants it! and prevents it from being forwarded 642 * anywhere else. Also checks if the rsvp daemon is running before 643 * grabbing the packet. 644 */ 645 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 646 goto ours; 647 648 /* 649 * Check our list of addresses, to see if the packet is for us. 650 * If we don't have any addresses, assume any unicast packet 651 * we receive might be for us (and let the upper layers deal 652 * with it). 653 */ 654 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) && 655 !(m->m_flags & (M_MCAST | M_BCAST))) 656 goto ours; 657 658 /* 659 * Cache the destination address of the packet; this may be 660 * changed by use of 'ipfw fwd'. 661 */ 662 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 663 664 /* 665 * Enable a consistency check between the destination address 666 * and the arrival interface for a unicast packet (the RFC 1122 667 * strong ES model) if IP forwarding is disabled and the packet 668 * is not locally generated and the packet is not subject to 669 * 'ipfw fwd'. 670 * 671 * XXX - Checking also should be disabled if the destination 672 * address is ipnat'ed to a different interface. 673 * 674 * XXX - Checking is incompatible with IP aliases added 675 * to the loopback interface instead of the interface where 676 * the packets are received. 677 */ 678 checkif = ip_checkinterface && 679 !ipforwarding && 680 m->m_pkthdr.rcvif != NULL && 681 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 682 next_hop == NULL; 683 684 /* 685 * Check for exact addresses in the hash bucket. 686 */ 687 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 688 ia = iac->ia; 689 690 /* 691 * If the address matches, verify that the packet 692 * arrived via the correct interface if checking is 693 * enabled. 694 */ 695 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 696 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 697 goto ours; 698 } 699 ia = NULL; 700 701 /* 702 * Check for broadcast addresses. 703 * 704 * Only accept broadcast packets that arrive via the matching 705 * interface. Reception of forwarded directed broadcasts would 706 * be handled via ip_forward() and ether_output() with the loopback 707 * into the stack for SIMPLEX interfaces handled by ether_output(). 708 */ 709 if (m->m_pkthdr.rcvif != NULL && 710 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 711 struct ifaddr_container *ifac; 712 713 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 714 ifa_link) { 715 struct ifaddr *ifa = ifac->ifa; 716 717 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 718 continue; 719 if (ifa->ifa_addr->sa_family != AF_INET) 720 continue; 721 ia = ifatoia(ifa); 722 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 723 pkt_dst.s_addr) 724 goto ours; 725 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 726 goto ours; 727 #ifdef BOOTP_COMPAT 728 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 729 goto ours; 730 #endif 731 } 732 } 733 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 734 struct in_multi *inm; 735 736 if (ip_mrouter != NULL) { 737 /* XXX Multicast routing is not MPSAFE yet */ 738 get_mplock(); 739 740 /* 741 * If we are acting as a multicast router, all 742 * incoming multicast packets are passed to the 743 * kernel-level multicast forwarding function. 744 * The packet is returned (relatively) intact; if 745 * ip_mforward() returns a non-zero value, the packet 746 * must be discarded, else it may be accepted below. 747 */ 748 if (ip_mforward != NULL && 749 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 750 rel_mplock(); 751 ipstat.ips_cantforward++; 752 m_freem(m); 753 return; 754 } 755 756 rel_mplock(); 757 758 /* 759 * The process-level routing daemon needs to receive 760 * all multicast IGMP packets, whether or not this 761 * host belongs to their destination groups. 762 */ 763 if (ip->ip_p == IPPROTO_IGMP) 764 goto ours; 765 ipstat.ips_forward++; 766 } 767 /* 768 * See if we belong to the destination multicast group on the 769 * arrival interface. 770 */ 771 inm = IN_LOOKUP_MULTI(&ip->ip_dst, m->m_pkthdr.rcvif); 772 if (inm == NULL) { 773 ipstat.ips_notmember++; 774 m_freem(m); 775 return; 776 } 777 goto ours; 778 } 779 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 780 goto ours; 781 if (ip->ip_dst.s_addr == INADDR_ANY) 782 goto ours; 783 784 /* 785 * FAITH(Firewall Aided Internet Translator) 786 */ 787 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 788 if (ip_keepfaith) { 789 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 790 goto ours; 791 } 792 m_freem(m); 793 return; 794 } 795 796 /* 797 * Not for us; forward if possible and desirable. 798 */ 799 if (!ipforwarding) { 800 ipstat.ips_cantforward++; 801 m_freem(m); 802 } else { 803 #ifdef IPSEC 804 /* 805 * Enforce inbound IPsec SPD. 806 */ 807 if (ipsec4_in_reject(m, NULL)) { 808 ipsecstat.in_polvio++; 809 goto bad; 810 } 811 #endif 812 #ifdef FAST_IPSEC 813 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 814 crit_enter(); 815 if (mtag != NULL) { 816 tdbi = (struct tdb_ident *)m_tag_data(mtag); 817 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 818 } else { 819 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 820 IP_FORWARDING, &error); 821 } 822 if (sp == NULL) { /* NB: can happen if error */ 823 crit_exit(); 824 /*XXX error stat???*/ 825 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 826 goto bad; 827 } 828 829 /* 830 * Check security policy against packet attributes. 831 */ 832 error = ipsec_in_reject(sp, m); 833 KEY_FREESP(&sp); 834 crit_exit(); 835 if (error) { 836 ipstat.ips_cantforward++; 837 goto bad; 838 } 839 #endif 840 ip_forward(m, using_srcrt, next_hop); 841 } 842 return; 843 844 ours: 845 846 /* 847 * IPSTEALTH: Process non-routing options only 848 * if the packet is destined for us. 849 */ 850 if (ipstealth && 851 hlen > sizeof(struct ip) && 852 ip_dooptions(m, 1, next_hop)) 853 return; 854 855 /* Count the packet in the ip address stats */ 856 if (ia != NULL) { 857 IFA_STAT_INC(&ia->ia_ifa, ipackets, 1); 858 IFA_STAT_INC(&ia->ia_ifa, ibytes, m->m_pkthdr.len); 859 } 860 861 /* 862 * If offset or IP_MF are set, must reassemble. 863 * Otherwise, nothing need be done. 864 * (We could look in the reassembly queue to see 865 * if the packet was previously fragmented, 866 * but it's not worth the time; just let them time out.) 867 */ 868 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 869 /* 870 * Attempt reassembly; if it succeeds, proceed. ip_reass() 871 * will return a different mbuf. 872 * 873 * NOTE: ip_reass() returns m with M_HASH cleared to force 874 * us to recharacterize the packet. 875 */ 876 m = ip_reass(m); 877 if (m == NULL) 878 return; 879 ip = mtod(m, struct ip *); 880 881 /* Get the header length of the reassembled packet */ 882 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 883 } else { 884 ip->ip_len -= hlen; 885 } 886 887 #ifdef IPSEC 888 /* 889 * enforce IPsec policy checking if we are seeing last header. 890 * note that we do not visit this with protocols with pcb layer 891 * code - like udp/tcp/raw ip. 892 */ 893 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 894 ipsec4_in_reject(m, NULL)) { 895 ipsecstat.in_polvio++; 896 goto bad; 897 } 898 #endif 899 #if FAST_IPSEC 900 /* 901 * enforce IPsec policy checking if we are seeing last header. 902 * note that we do not visit this with protocols with pcb layer 903 * code - like udp/tcp/raw ip. 904 */ 905 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 906 /* 907 * Check if the packet has already had IPsec processing 908 * done. If so, then just pass it along. This tag gets 909 * set during AH, ESP, etc. input handling, before the 910 * packet is returned to the ip input queue for delivery. 911 */ 912 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 913 crit_enter(); 914 if (mtag != NULL) { 915 tdbi = (struct tdb_ident *)m_tag_data(mtag); 916 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 917 } else { 918 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 919 IP_FORWARDING, &error); 920 } 921 if (sp != NULL) { 922 /* 923 * Check security policy against packet attributes. 924 */ 925 error = ipsec_in_reject(sp, m); 926 KEY_FREESP(&sp); 927 } else { 928 /* XXX error stat??? */ 929 error = EINVAL; 930 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 931 crit_exit(); 932 goto bad; 933 } 934 crit_exit(); 935 if (error) 936 goto bad; 937 } 938 #endif /* FAST_IPSEC */ 939 940 /* 941 * We must forward the packet to the correct protocol thread if 942 * we are not already in it. 943 * 944 * NOTE: ip_len is now in host form. ip_len is not adjusted 945 * further for protocol processing, instead we pass hlen 946 * to the protosw and let it deal with it. 947 */ 948 ipstat.ips_delivered++; 949 950 if ((m->m_flags & M_HASH) == 0) { 951 #ifdef RSS_DEBUG 952 atomic_add_long(&ip_rehash_count, 1); 953 #endif 954 ip->ip_len = htons(ip->ip_len + hlen); 955 ip->ip_off = htons(ip->ip_off); 956 957 ip_hashfn(&m, 0, IP_MPORT_IN); 958 if (m == NULL) 959 return; 960 961 ip = mtod(m, struct ip *); 962 ip->ip_len = ntohs(ip->ip_len) - hlen; 963 ip->ip_off = ntohs(ip->ip_off); 964 KKASSERT(m->m_flags & M_HASH); 965 } 966 port = netisr_hashport(m->m_pkthdr.hash); 967 968 if (port != &curthread->td_msgport) { 969 struct netmsg_packet *pmsg; 970 971 #ifdef RSS_DEBUG 972 atomic_add_long(&ip_dispatch_slow, 1); 973 #endif 974 975 pmsg = &m->m_hdr.mh_netmsg; 976 netmsg_init(&pmsg->base, NULL, &netisr_apanic_rport, 977 0, transport_processing_handler); 978 pmsg->nm_packet = m; 979 pmsg->base.lmsg.u.ms_result = hlen; 980 lwkt_sendmsg(port, &pmsg->base.lmsg); 981 } else { 982 #ifdef RSS_DEBUG 983 atomic_add_long(&ip_dispatch_fast, 1); 984 #endif 985 transport_processing_oncpu(m, hlen, ip); 986 } 987 return; 988 989 bad: 990 m_freem(m); 991 } 992 993 /* 994 * Take incoming datagram fragment and try to reassemble it into 995 * whole datagram. If a chain for reassembly of this datagram already 996 * exists, then it is given as fp; otherwise have to make a chain. 997 */ 998 struct mbuf * 999 ip_reass(struct mbuf *m) 1000 { 1001 struct ip *ip = mtod(m, struct ip *); 1002 struct mbuf *p = NULL, *q, *nq; 1003 struct mbuf *n; 1004 struct ipq *fp = NULL; 1005 struct ipqhead *head; 1006 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 1007 int i, next; 1008 u_short sum; 1009 1010 /* If maxnipq is 0, never accept fragments. */ 1011 if (maxnipq == 0) { 1012 ipstat.ips_fragments++; 1013 ipstat.ips_fragdropped++; 1014 m_freem(m); 1015 return NULL; 1016 } 1017 1018 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 1019 /* 1020 * Look for queue of fragments of this datagram. 1021 */ 1022 lwkt_gettoken(&ipq_token); 1023 head = &ipq[sum]; 1024 TAILQ_FOREACH(fp, head, ipq_list) { 1025 if (ip->ip_id == fp->ipq_id && 1026 ip->ip_src.s_addr == fp->ipq_src.s_addr && 1027 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 1028 ip->ip_p == fp->ipq_p) 1029 goto found; 1030 } 1031 1032 fp = NULL; 1033 1034 /* 1035 * Enforce upper bound on number of fragmented packets 1036 * for which we attempt reassembly; 1037 * If maxnipq is -1, accept all fragments without limitation. 1038 */ 1039 if (nipq > maxnipq && maxnipq > 0) { 1040 /* 1041 * drop something from the tail of the current queue 1042 * before proceeding further 1043 */ 1044 struct ipq *q = TAILQ_LAST(head, ipqhead); 1045 if (q == NULL) { 1046 /* 1047 * The current queue is empty, 1048 * so drop from one of the others. 1049 */ 1050 for (i = 0; i < IPREASS_NHASH; i++) { 1051 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 1052 if (r) { 1053 ipstat.ips_fragtimeout += r->ipq_nfrags; 1054 ip_freef(&ipq[i], r); 1055 break; 1056 } 1057 } 1058 } else { 1059 ipstat.ips_fragtimeout += q->ipq_nfrags; 1060 ip_freef(head, q); 1061 } 1062 } 1063 found: 1064 /* 1065 * Adjust ip_len to not reflect header, 1066 * convert offset of this to bytes. 1067 */ 1068 ip->ip_len -= hlen; 1069 if (ip->ip_off & IP_MF) { 1070 /* 1071 * Make sure that fragments have a data length 1072 * that's a non-zero multiple of 8 bytes. 1073 */ 1074 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 1075 ipstat.ips_toosmall++; /* XXX */ 1076 m_freem(m); 1077 goto done; 1078 } 1079 m->m_flags |= M_FRAG; 1080 } else { 1081 m->m_flags &= ~M_FRAG; 1082 } 1083 ip->ip_off <<= 3; 1084 1085 ipstat.ips_fragments++; 1086 m->m_pkthdr.header = ip; 1087 1088 /* 1089 * If the hardware has not done csum over this fragment 1090 * then csum_data is not valid at all. 1091 */ 1092 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) 1093 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) { 1094 m->m_pkthdr.csum_data = 0; 1095 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR); 1096 } 1097 1098 /* 1099 * Presence of header sizes in mbufs 1100 * would confuse code below. 1101 */ 1102 m->m_data += hlen; 1103 m->m_len -= hlen; 1104 1105 /* 1106 * If first fragment to arrive, create a reassembly queue. 1107 */ 1108 if (fp == NULL) { 1109 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1110 goto dropfrag; 1111 TAILQ_INSERT_HEAD(head, fp, ipq_list); 1112 nipq++; 1113 fp->ipq_nfrags = 1; 1114 fp->ipq_ttl = IPFRAGTTL; 1115 fp->ipq_p = ip->ip_p; 1116 fp->ipq_id = ip->ip_id; 1117 fp->ipq_src = ip->ip_src; 1118 fp->ipq_dst = ip->ip_dst; 1119 fp->ipq_frags = m; 1120 m->m_nextpkt = NULL; 1121 goto inserted; 1122 } else { 1123 fp->ipq_nfrags++; 1124 } 1125 1126 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1127 1128 /* 1129 * Find a segment which begins after this one does. 1130 */ 1131 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1132 if (GETIP(q)->ip_off > ip->ip_off) 1133 break; 1134 } 1135 1136 /* 1137 * If there is a preceding segment, it may provide some of 1138 * our data already. If so, drop the data from the incoming 1139 * segment. If it provides all of our data, drop us, otherwise 1140 * stick new segment in the proper place. 1141 * 1142 * If some of the data is dropped from the the preceding 1143 * segment, then it's checksum is invalidated. 1144 */ 1145 if (p) { 1146 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1147 if (i > 0) { 1148 if (i >= ip->ip_len) 1149 goto dropfrag; 1150 m_adj(m, i); 1151 m->m_pkthdr.csum_flags = 0; 1152 ip->ip_off += i; 1153 ip->ip_len -= i; 1154 } 1155 m->m_nextpkt = p->m_nextpkt; 1156 p->m_nextpkt = m; 1157 } else { 1158 m->m_nextpkt = fp->ipq_frags; 1159 fp->ipq_frags = m; 1160 } 1161 1162 /* 1163 * While we overlap succeeding segments trim them or, 1164 * if they are completely covered, dequeue them. 1165 */ 1166 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1167 q = nq) { 1168 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1169 if (i < GETIP(q)->ip_len) { 1170 GETIP(q)->ip_len -= i; 1171 GETIP(q)->ip_off += i; 1172 m_adj(q, i); 1173 q->m_pkthdr.csum_flags = 0; 1174 break; 1175 } 1176 nq = q->m_nextpkt; 1177 m->m_nextpkt = nq; 1178 ipstat.ips_fragdropped++; 1179 fp->ipq_nfrags--; 1180 q->m_nextpkt = NULL; 1181 m_freem(q); 1182 } 1183 1184 inserted: 1185 /* 1186 * Check for complete reassembly and perform frag per packet 1187 * limiting. 1188 * 1189 * Frag limiting is performed here so that the nth frag has 1190 * a chance to complete the packet before we drop the packet. 1191 * As a result, n+1 frags are actually allowed per packet, but 1192 * only n will ever be stored. (n = maxfragsperpacket.) 1193 * 1194 */ 1195 next = 0; 1196 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1197 if (GETIP(q)->ip_off != next) { 1198 if (fp->ipq_nfrags > maxfragsperpacket) { 1199 ipstat.ips_fragdropped += fp->ipq_nfrags; 1200 ip_freef(head, fp); 1201 } 1202 goto done; 1203 } 1204 next += GETIP(q)->ip_len; 1205 } 1206 /* Make sure the last packet didn't have the IP_MF flag */ 1207 if (p->m_flags & M_FRAG) { 1208 if (fp->ipq_nfrags > maxfragsperpacket) { 1209 ipstat.ips_fragdropped += fp->ipq_nfrags; 1210 ip_freef(head, fp); 1211 } 1212 goto done; 1213 } 1214 1215 /* 1216 * Reassembly is complete. Make sure the packet is a sane size. 1217 */ 1218 q = fp->ipq_frags; 1219 ip = GETIP(q); 1220 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1221 ipstat.ips_toolong++; 1222 ipstat.ips_fragdropped += fp->ipq_nfrags; 1223 ip_freef(head, fp); 1224 goto done; 1225 } 1226 1227 /* 1228 * Concatenate fragments. 1229 */ 1230 m = q; 1231 n = m->m_next; 1232 m->m_next = NULL; 1233 m_cat(m, n); 1234 nq = q->m_nextpkt; 1235 q->m_nextpkt = NULL; 1236 for (q = nq; q != NULL; q = nq) { 1237 nq = q->m_nextpkt; 1238 q->m_nextpkt = NULL; 1239 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1240 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1241 m_cat(m, q); 1242 } 1243 1244 /* 1245 * Clean up the 1's complement checksum. Carry over 16 bits must 1246 * be added back. This assumes no more then 65535 packet fragments 1247 * were reassembled. A second carry can also occur (but not a third). 1248 */ 1249 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + 1250 (m->m_pkthdr.csum_data >> 16); 1251 if (m->m_pkthdr.csum_data > 0xFFFF) 1252 m->m_pkthdr.csum_data -= 0xFFFF; 1253 1254 /* 1255 * Create header for new ip packet by 1256 * modifying header of first packet; 1257 * dequeue and discard fragment reassembly header. 1258 * Make header visible. 1259 */ 1260 ip->ip_len = next; 1261 ip->ip_src = fp->ipq_src; 1262 ip->ip_dst = fp->ipq_dst; 1263 TAILQ_REMOVE(head, fp, ipq_list); 1264 nipq--; 1265 mpipe_free(&ipq_mpipe, fp); 1266 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1267 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1268 /* some debugging cruft by sklower, below, will go away soon */ 1269 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1270 int plen = 0; 1271 1272 for (n = m; n; n = n->m_next) 1273 plen += n->m_len; 1274 m->m_pkthdr.len = plen; 1275 } 1276 1277 /* 1278 * Reassembly complete, return the next protocol. 1279 * 1280 * Be sure to clear M_HASH to force the packet 1281 * to be re-characterized. 1282 * 1283 * Clear M_FRAG, we are no longer a fragment. 1284 */ 1285 m->m_flags &= ~(M_HASH | M_FRAG); 1286 1287 ipstat.ips_reassembled++; 1288 lwkt_reltoken(&ipq_token); 1289 return (m); 1290 1291 dropfrag: 1292 ipstat.ips_fragdropped++; 1293 if (fp != NULL) 1294 fp->ipq_nfrags--; 1295 m_freem(m); 1296 done: 1297 lwkt_reltoken(&ipq_token); 1298 return (NULL); 1299 1300 #undef GETIP 1301 } 1302 1303 /* 1304 * Free a fragment reassembly header and all 1305 * associated datagrams. 1306 * 1307 * Called with ipq_token held. 1308 */ 1309 static void 1310 ip_freef(struct ipqhead *fhp, struct ipq *fp) 1311 { 1312 struct mbuf *q; 1313 1314 /* 1315 * Remove first to protect against blocking 1316 */ 1317 TAILQ_REMOVE(fhp, fp, ipq_list); 1318 1319 /* 1320 * Clean out at our leisure 1321 */ 1322 while (fp->ipq_frags) { 1323 q = fp->ipq_frags; 1324 fp->ipq_frags = q->m_nextpkt; 1325 q->m_nextpkt = NULL; 1326 m_freem(q); 1327 } 1328 mpipe_free(&ipq_mpipe, fp); 1329 nipq--; 1330 } 1331 1332 /* 1333 * IP timer processing; 1334 * if a timer expires on a reassembly 1335 * queue, discard it. 1336 */ 1337 void 1338 ip_slowtimo(void) 1339 { 1340 struct ipq *fp, *fp_temp; 1341 struct ipqhead *head; 1342 int i; 1343 1344 lwkt_gettoken(&ipq_token); 1345 for (i = 0; i < IPREASS_NHASH; i++) { 1346 head = &ipq[i]; 1347 TAILQ_FOREACH_MUTABLE(fp, head, ipq_list, fp_temp) { 1348 if (--fp->ipq_ttl == 0) { 1349 ipstat.ips_fragtimeout += fp->ipq_nfrags; 1350 ip_freef(head, fp); 1351 } 1352 } 1353 } 1354 /* 1355 * If we are over the maximum number of fragments 1356 * (due to the limit being lowered), drain off 1357 * enough to get down to the new limit. 1358 */ 1359 if (maxnipq >= 0 && nipq > maxnipq) { 1360 for (i = 0; i < IPREASS_NHASH; i++) { 1361 head = &ipq[i]; 1362 while (nipq > maxnipq && !TAILQ_EMPTY(head)) { 1363 ipstat.ips_fragdropped += 1364 TAILQ_FIRST(head)->ipq_nfrags; 1365 ip_freef(head, TAILQ_FIRST(head)); 1366 } 1367 } 1368 } 1369 lwkt_reltoken(&ipq_token); 1370 ipflow_slowtimo(); 1371 } 1372 1373 /* 1374 * Drain off all datagram fragments. 1375 */ 1376 void 1377 ip_drain(void) 1378 { 1379 struct ipqhead *head; 1380 int i; 1381 1382 lwkt_gettoken(&ipq_token); 1383 for (i = 0; i < IPREASS_NHASH; i++) { 1384 head = &ipq[i]; 1385 while (!TAILQ_EMPTY(head)) { 1386 ipstat.ips_fragdropped += TAILQ_FIRST(head)->ipq_nfrags; 1387 ip_freef(head, TAILQ_FIRST(head)); 1388 } 1389 } 1390 lwkt_reltoken(&ipq_token); 1391 in_rtqdrain(); 1392 } 1393 1394 /* 1395 * Do option processing on a datagram, 1396 * possibly discarding it if bad options are encountered, 1397 * or forwarding it if source-routed. 1398 * The pass argument is used when operating in the IPSTEALTH 1399 * mode to tell what options to process: 1400 * [LS]SRR (pass 0) or the others (pass 1). 1401 * The reason for as many as two passes is that when doing IPSTEALTH, 1402 * non-routing options should be processed only if the packet is for us. 1403 * Returns 1 if packet has been forwarded/freed, 1404 * 0 if the packet should be processed further. 1405 */ 1406 static int 1407 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1408 { 1409 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1410 struct ip *ip = mtod(m, struct ip *); 1411 u_char *cp; 1412 struct in_ifaddr *ia; 1413 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1414 boolean_t forward = FALSE; 1415 struct in_addr *sin, dst; 1416 n_time ntime; 1417 1418 dst = ip->ip_dst; 1419 cp = (u_char *)(ip + 1); 1420 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1421 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1422 opt = cp[IPOPT_OPTVAL]; 1423 if (opt == IPOPT_EOL) 1424 break; 1425 if (opt == IPOPT_NOP) 1426 optlen = 1; 1427 else { 1428 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1429 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1430 goto bad; 1431 } 1432 optlen = cp[IPOPT_OLEN]; 1433 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1434 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1435 goto bad; 1436 } 1437 } 1438 switch (opt) { 1439 1440 default: 1441 break; 1442 1443 /* 1444 * Source routing with record. 1445 * Find interface with current destination address. 1446 * If none on this machine then drop if strictly routed, 1447 * or do nothing if loosely routed. 1448 * Record interface address and bring up next address 1449 * component. If strictly routed make sure next 1450 * address is on directly accessible net. 1451 */ 1452 case IPOPT_LSRR: 1453 case IPOPT_SSRR: 1454 if (ipstealth && pass > 0) 1455 break; 1456 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1457 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1458 goto bad; 1459 } 1460 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1461 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1462 goto bad; 1463 } 1464 ipaddr.sin_addr = ip->ip_dst; 1465 ia = (struct in_ifaddr *) 1466 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1467 if (ia == NULL) { 1468 if (opt == IPOPT_SSRR) { 1469 type = ICMP_UNREACH; 1470 code = ICMP_UNREACH_SRCFAIL; 1471 goto bad; 1472 } 1473 if (!ip_dosourceroute) 1474 goto nosourcerouting; 1475 /* 1476 * Loose routing, and not at next destination 1477 * yet; nothing to do except forward. 1478 */ 1479 break; 1480 } 1481 off--; /* 0 origin */ 1482 if (off > optlen - (int)sizeof(struct in_addr)) { 1483 /* 1484 * End of source route. Should be for us. 1485 */ 1486 if (!ip_acceptsourceroute) 1487 goto nosourcerouting; 1488 save_rte(m, cp, ip->ip_src); 1489 break; 1490 } 1491 if (ipstealth) 1492 goto dropit; 1493 if (!ip_dosourceroute) { 1494 if (ipforwarding) { 1495 char buf[sizeof "aaa.bbb.ccc.ddd"]; 1496 1497 /* 1498 * Acting as a router, so generate ICMP 1499 */ 1500 nosourcerouting: 1501 strcpy(buf, inet_ntoa(ip->ip_dst)); 1502 log(LOG_WARNING, 1503 "attempted source route from %s to %s\n", 1504 inet_ntoa(ip->ip_src), buf); 1505 type = ICMP_UNREACH; 1506 code = ICMP_UNREACH_SRCFAIL; 1507 goto bad; 1508 } else { 1509 /* 1510 * Not acting as a router, 1511 * so silently drop. 1512 */ 1513 dropit: 1514 ipstat.ips_cantforward++; 1515 m_freem(m); 1516 return (1); 1517 } 1518 } 1519 1520 /* 1521 * locate outgoing interface 1522 */ 1523 memcpy(&ipaddr.sin_addr, cp + off, 1524 sizeof ipaddr.sin_addr); 1525 1526 if (opt == IPOPT_SSRR) { 1527 #define INA struct in_ifaddr * 1528 #define SA struct sockaddr * 1529 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1530 == NULL) 1531 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1532 } else { 1533 ia = ip_rtaddr(ipaddr.sin_addr, NULL); 1534 } 1535 if (ia == NULL) { 1536 type = ICMP_UNREACH; 1537 code = ICMP_UNREACH_SRCFAIL; 1538 goto bad; 1539 } 1540 ip->ip_dst = ipaddr.sin_addr; 1541 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1542 sizeof(struct in_addr)); 1543 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1544 /* 1545 * Let ip_intr's mcast routing check handle mcast pkts 1546 */ 1547 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1548 break; 1549 1550 case IPOPT_RR: 1551 if (ipstealth && pass == 0) 1552 break; 1553 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1554 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1555 goto bad; 1556 } 1557 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1558 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1559 goto bad; 1560 } 1561 /* 1562 * If no space remains, ignore. 1563 */ 1564 off--; /* 0 origin */ 1565 if (off > optlen - (int)sizeof(struct in_addr)) 1566 break; 1567 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1568 sizeof ipaddr.sin_addr); 1569 /* 1570 * locate outgoing interface; if we're the destination, 1571 * use the incoming interface (should be same). 1572 */ 1573 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1574 (ia = ip_rtaddr(ipaddr.sin_addr, NULL)) == NULL) { 1575 type = ICMP_UNREACH; 1576 code = ICMP_UNREACH_HOST; 1577 goto bad; 1578 } 1579 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1580 sizeof(struct in_addr)); 1581 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1582 break; 1583 1584 case IPOPT_TS: 1585 if (ipstealth && pass == 0) 1586 break; 1587 code = cp - (u_char *)ip; 1588 if (optlen < 4 || optlen > 40) { 1589 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1590 goto bad; 1591 } 1592 if ((off = cp[IPOPT_OFFSET]) < 5) { 1593 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1594 goto bad; 1595 } 1596 if (off > optlen - (int)sizeof(int32_t)) { 1597 cp[IPOPT_OFFSET + 1] += (1 << 4); 1598 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1599 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1600 goto bad; 1601 } 1602 break; 1603 } 1604 off--; /* 0 origin */ 1605 sin = (struct in_addr *)(cp + off); 1606 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1607 1608 case IPOPT_TS_TSONLY: 1609 break; 1610 1611 case IPOPT_TS_TSANDADDR: 1612 if (off + sizeof(n_time) + 1613 sizeof(struct in_addr) > optlen) { 1614 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1615 goto bad; 1616 } 1617 ipaddr.sin_addr = dst; 1618 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1619 m->m_pkthdr.rcvif); 1620 if (ia == NULL) 1621 continue; 1622 memcpy(sin, &IA_SIN(ia)->sin_addr, 1623 sizeof(struct in_addr)); 1624 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1625 off += sizeof(struct in_addr); 1626 break; 1627 1628 case IPOPT_TS_PRESPEC: 1629 if (off + sizeof(n_time) + 1630 sizeof(struct in_addr) > optlen) { 1631 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1632 goto bad; 1633 } 1634 memcpy(&ipaddr.sin_addr, sin, 1635 sizeof(struct in_addr)); 1636 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1637 continue; 1638 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1639 off += sizeof(struct in_addr); 1640 break; 1641 1642 default: 1643 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1644 goto bad; 1645 } 1646 ntime = iptime(); 1647 memcpy(cp + off, &ntime, sizeof(n_time)); 1648 cp[IPOPT_OFFSET] += sizeof(n_time); 1649 } 1650 } 1651 if (forward && ipforwarding) { 1652 ip_forward(m, TRUE, next_hop); 1653 return (1); 1654 } 1655 return (0); 1656 bad: 1657 icmp_error(m, type, code, 0, 0); 1658 ipstat.ips_badoptions++; 1659 return (1); 1660 } 1661 1662 /* 1663 * Given address of next destination (final or next hop), 1664 * return internet address info of interface to be used to get there. 1665 */ 1666 struct in_ifaddr * 1667 ip_rtaddr(struct in_addr dst, struct route *ro0) 1668 { 1669 struct route sro, *ro; 1670 struct sockaddr_in *sin; 1671 struct in_ifaddr *ia; 1672 1673 if (ro0 != NULL) { 1674 ro = ro0; 1675 } else { 1676 bzero(&sro, sizeof(sro)); 1677 ro = &sro; 1678 } 1679 1680 sin = (struct sockaddr_in *)&ro->ro_dst; 1681 1682 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1683 if (ro->ro_rt != NULL) { 1684 RTFREE(ro->ro_rt); 1685 ro->ro_rt = NULL; 1686 } 1687 sin->sin_family = AF_INET; 1688 sin->sin_len = sizeof *sin; 1689 sin->sin_addr = dst; 1690 rtalloc_ign(ro, RTF_PRCLONING); 1691 } 1692 1693 if (ro->ro_rt == NULL) 1694 return (NULL); 1695 1696 ia = ifatoia(ro->ro_rt->rt_ifa); 1697 1698 if (ro == &sro) 1699 RTFREE(ro->ro_rt); 1700 return ia; 1701 } 1702 1703 /* 1704 * Save incoming source route for use in replies, 1705 * to be picked up later by ip_srcroute if the receiver is interested. 1706 */ 1707 static void 1708 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1709 { 1710 struct m_tag *mtag; 1711 struct ip_srcrt_opt *opt; 1712 unsigned olen; 1713 1714 mtag = m_tag_get(PACKET_TAG_IPSRCRT, sizeof(*opt), MB_DONTWAIT); 1715 if (mtag == NULL) 1716 return; 1717 opt = m_tag_data(mtag); 1718 1719 olen = option[IPOPT_OLEN]; 1720 #ifdef DIAGNOSTIC 1721 if (ipprintfs) 1722 kprintf("save_rte: olen %d\n", olen); 1723 #endif 1724 if (olen > sizeof(opt->ip_srcrt) - (1 + sizeof(dst))) { 1725 m_tag_free(mtag); 1726 return; 1727 } 1728 bcopy(option, opt->ip_srcrt.srcopt, olen); 1729 opt->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1730 opt->ip_srcrt.dst = dst; 1731 m_tag_prepend(m, mtag); 1732 } 1733 1734 /* 1735 * Retrieve incoming source route for use in replies, 1736 * in the same form used by setsockopt. 1737 * The first hop is placed before the options, will be removed later. 1738 */ 1739 struct mbuf * 1740 ip_srcroute(struct mbuf *m0) 1741 { 1742 struct in_addr *p, *q; 1743 struct mbuf *m; 1744 struct m_tag *mtag; 1745 struct ip_srcrt_opt *opt; 1746 1747 if (m0 == NULL) 1748 return NULL; 1749 1750 mtag = m_tag_find(m0, PACKET_TAG_IPSRCRT, NULL); 1751 if (mtag == NULL) 1752 return NULL; 1753 opt = m_tag_data(mtag); 1754 1755 if (opt->ip_nhops == 0) 1756 return (NULL); 1757 m = m_get(MB_DONTWAIT, MT_HEADER); 1758 if (m == NULL) 1759 return (NULL); 1760 1761 #define OPTSIZ (sizeof(opt->ip_srcrt.nop) + sizeof(opt->ip_srcrt.srcopt)) 1762 1763 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1764 m->m_len = opt->ip_nhops * sizeof(struct in_addr) + 1765 sizeof(struct in_addr) + OPTSIZ; 1766 #ifdef DIAGNOSTIC 1767 if (ipprintfs) { 1768 kprintf("ip_srcroute: nhops %d mlen %d", 1769 opt->ip_nhops, m->m_len); 1770 } 1771 #endif 1772 1773 /* 1774 * First save first hop for return route 1775 */ 1776 p = &opt->ip_srcrt.route[opt->ip_nhops - 1]; 1777 *(mtod(m, struct in_addr *)) = *p--; 1778 #ifdef DIAGNOSTIC 1779 if (ipprintfs) 1780 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1781 #endif 1782 1783 /* 1784 * Copy option fields and padding (nop) to mbuf. 1785 */ 1786 opt->ip_srcrt.nop = IPOPT_NOP; 1787 opt->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1788 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &opt->ip_srcrt.nop, 1789 OPTSIZ); 1790 q = (struct in_addr *)(mtod(m, caddr_t) + 1791 sizeof(struct in_addr) + OPTSIZ); 1792 #undef OPTSIZ 1793 /* 1794 * Record return path as an IP source route, 1795 * reversing the path (pointers are now aligned). 1796 */ 1797 while (p >= opt->ip_srcrt.route) { 1798 #ifdef DIAGNOSTIC 1799 if (ipprintfs) 1800 kprintf(" %x", ntohl(q->s_addr)); 1801 #endif 1802 *q++ = *p--; 1803 } 1804 /* 1805 * Last hop goes to final destination. 1806 */ 1807 *q = opt->ip_srcrt.dst; 1808 m_tag_delete(m0, mtag); 1809 #ifdef DIAGNOSTIC 1810 if (ipprintfs) 1811 kprintf(" %x\n", ntohl(q->s_addr)); 1812 #endif 1813 return (m); 1814 } 1815 1816 /* 1817 * Strip out IP options. 1818 */ 1819 void 1820 ip_stripoptions(struct mbuf *m) 1821 { 1822 int datalen; 1823 struct ip *ip = mtod(m, struct ip *); 1824 caddr_t opts; 1825 int optlen; 1826 1827 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1828 opts = (caddr_t)(ip + 1); 1829 datalen = m->m_len - (sizeof(struct ip) + optlen); 1830 bcopy(opts + optlen, opts, datalen); 1831 m->m_len -= optlen; 1832 if (m->m_flags & M_PKTHDR) 1833 m->m_pkthdr.len -= optlen; 1834 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1835 } 1836 1837 u_char inetctlerrmap[PRC_NCMDS] = { 1838 0, 0, 0, 0, 1839 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1840 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1841 EMSGSIZE, EHOSTUNREACH, 0, 0, 1842 0, 0, 0, 0, 1843 ENOPROTOOPT, ECONNREFUSED 1844 }; 1845 1846 /* 1847 * Forward a packet. If some error occurs return the sender 1848 * an icmp packet. Note we can't always generate a meaningful 1849 * icmp message because icmp doesn't have a large enough repertoire 1850 * of codes and types. 1851 * 1852 * If not forwarding, just drop the packet. This could be confusing 1853 * if ipforwarding was zero but some routing protocol was advancing 1854 * us as a gateway to somewhere. However, we must let the routing 1855 * protocol deal with that. 1856 * 1857 * The using_srcrt parameter indicates whether the packet is being forwarded 1858 * via a source route. 1859 */ 1860 void 1861 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop) 1862 { 1863 struct ip *ip = mtod(m, struct ip *); 1864 struct rtentry *rt; 1865 struct route fwd_ro; 1866 int error, type = 0, code = 0, destmtu = 0; 1867 struct mbuf *mcopy, *mtemp = NULL; 1868 n_long dest; 1869 struct in_addr pkt_dst; 1870 1871 dest = INADDR_ANY; 1872 /* 1873 * Cache the destination address of the packet; this may be 1874 * changed by use of 'ipfw fwd'. 1875 */ 1876 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 1877 1878 #ifdef DIAGNOSTIC 1879 if (ipprintfs) 1880 kprintf("forward: src %x dst %x ttl %x\n", 1881 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1882 #endif 1883 1884 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1885 ipstat.ips_cantforward++; 1886 m_freem(m); 1887 return; 1888 } 1889 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1890 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1891 return; 1892 } 1893 1894 bzero(&fwd_ro, sizeof(fwd_ro)); 1895 ip_rtaddr(pkt_dst, &fwd_ro); 1896 if (fwd_ro.ro_rt == NULL) { 1897 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1898 return; 1899 } 1900 rt = fwd_ro.ro_rt; 1901 1902 if (curthread->td_type == TD_TYPE_NETISR) { 1903 /* 1904 * Save the IP header and at most 8 bytes of the payload, 1905 * in case we need to generate an ICMP message to the src. 1906 */ 1907 mtemp = ipforward_mtemp[mycpuid]; 1908 KASSERT((mtemp->m_flags & M_EXT) == 0 && 1909 mtemp->m_data == mtemp->m_pktdat && 1910 m_tag_first(mtemp) == NULL, 1911 ("ip_forward invalid mtemp1")); 1912 1913 if (!m_dup_pkthdr(mtemp, m, MB_DONTWAIT)) { 1914 /* 1915 * It's probably ok if the pkthdr dup fails (because 1916 * the deep copy of the tag chain failed), but for now 1917 * be conservative and just discard the copy since 1918 * code below may some day want the tags. 1919 */ 1920 mtemp = NULL; 1921 } else { 1922 mtemp->m_type = m->m_type; 1923 mtemp->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1924 (int)ip->ip_len); 1925 mtemp->m_pkthdr.len = mtemp->m_len; 1926 m_copydata(m, 0, mtemp->m_len, mtod(mtemp, caddr_t)); 1927 } 1928 } 1929 1930 if (!ipstealth) 1931 ip->ip_ttl -= IPTTLDEC; 1932 1933 /* 1934 * If forwarding packet using same interface that it came in on, 1935 * perhaps should send a redirect to sender to shortcut a hop. 1936 * Only send redirect if source is sending directly to us, 1937 * and if packet was not source routed (or has any options). 1938 * Also, don't send redirect if forwarding using a default route 1939 * or a route modified by a redirect. 1940 */ 1941 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1942 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1943 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1944 ipsendredirects && !using_srcrt && next_hop == NULL) { 1945 u_long src = ntohl(ip->ip_src.s_addr); 1946 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa; 1947 1948 if (rt_ifa != NULL && 1949 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) { 1950 if (rt->rt_flags & RTF_GATEWAY) 1951 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1952 else 1953 dest = pkt_dst.s_addr; 1954 /* 1955 * Router requirements says to only send 1956 * host redirects. 1957 */ 1958 type = ICMP_REDIRECT; 1959 code = ICMP_REDIRECT_HOST; 1960 #ifdef DIAGNOSTIC 1961 if (ipprintfs) 1962 kprintf("redirect (%d) to %x\n", code, dest); 1963 #endif 1964 } 1965 } 1966 1967 error = ip_output(m, NULL, &fwd_ro, IP_FORWARDING, NULL, NULL); 1968 if (error == 0) { 1969 ipstat.ips_forward++; 1970 if (type == 0) { 1971 if (mtemp) 1972 ipflow_create(&fwd_ro, mtemp); 1973 goto done; 1974 } else { 1975 ipstat.ips_redirectsent++; 1976 } 1977 } else { 1978 ipstat.ips_cantforward++; 1979 } 1980 1981 if (mtemp == NULL) 1982 goto done; 1983 1984 /* 1985 * Errors that do not require generating ICMP message 1986 */ 1987 switch (error) { 1988 case ENOBUFS: 1989 /* 1990 * A router should not generate ICMP_SOURCEQUENCH as 1991 * required in RFC1812 Requirements for IP Version 4 Routers. 1992 * Source quench could be a big problem under DoS attacks, 1993 * or if the underlying interface is rate-limited. 1994 * Those who need source quench packets may re-enable them 1995 * via the net.inet.ip.sendsourcequench sysctl. 1996 */ 1997 if (!ip_sendsourcequench) 1998 goto done; 1999 break; 2000 2001 case EACCES: /* ipfw denied packet */ 2002 goto done; 2003 } 2004 2005 KASSERT((mtemp->m_flags & M_EXT) == 0 && 2006 mtemp->m_data == mtemp->m_pktdat, 2007 ("ip_forward invalid mtemp2")); 2008 mcopy = m_copym(mtemp, 0, mtemp->m_len, MB_DONTWAIT); 2009 if (mcopy == NULL) 2010 goto done; 2011 2012 /* 2013 * Send ICMP message. 2014 */ 2015 switch (error) { 2016 case 0: /* forwarded, but need redirect */ 2017 /* type, code set above */ 2018 break; 2019 2020 case ENETUNREACH: /* shouldn't happen, checked above */ 2021 case EHOSTUNREACH: 2022 case ENETDOWN: 2023 case EHOSTDOWN: 2024 default: 2025 type = ICMP_UNREACH; 2026 code = ICMP_UNREACH_HOST; 2027 break; 2028 2029 case EMSGSIZE: 2030 type = ICMP_UNREACH; 2031 code = ICMP_UNREACH_NEEDFRAG; 2032 #ifdef IPSEC 2033 /* 2034 * If the packet is routed over IPsec tunnel, tell the 2035 * originator the tunnel MTU. 2036 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2037 * XXX quickhack!!! 2038 */ 2039 if (fwd_ro.ro_rt != NULL) { 2040 struct secpolicy *sp = NULL; 2041 int ipsecerror; 2042 int ipsechdr; 2043 struct route *ro; 2044 2045 sp = ipsec4_getpolicybyaddr(mcopy, 2046 IPSEC_DIR_OUTBOUND, 2047 IP_FORWARDING, 2048 &ipsecerror); 2049 2050 if (sp == NULL) 2051 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2052 else { 2053 /* count IPsec header size */ 2054 ipsechdr = ipsec4_hdrsiz(mcopy, 2055 IPSEC_DIR_OUTBOUND, 2056 NULL); 2057 2058 /* 2059 * find the correct route for outer IPv4 2060 * header, compute tunnel MTU. 2061 * 2062 */ 2063 if (sp->req != NULL && sp->req->sav != NULL && 2064 sp->req->sav->sah != NULL) { 2065 ro = &sp->req->sav->sah->sa_route; 2066 if (ro->ro_rt != NULL && 2067 ro->ro_rt->rt_ifp != NULL) { 2068 destmtu = 2069 ro->ro_rt->rt_ifp->if_mtu; 2070 destmtu -= ipsechdr; 2071 } 2072 } 2073 2074 key_freesp(sp); 2075 } 2076 } 2077 #elif FAST_IPSEC 2078 /* 2079 * If the packet is routed over IPsec tunnel, tell the 2080 * originator the tunnel MTU. 2081 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2082 * XXX quickhack!!! 2083 */ 2084 if (fwd_ro.ro_rt != NULL) { 2085 struct secpolicy *sp = NULL; 2086 int ipsecerror; 2087 int ipsechdr; 2088 struct route *ro; 2089 2090 sp = ipsec_getpolicybyaddr(mcopy, 2091 IPSEC_DIR_OUTBOUND, 2092 IP_FORWARDING, 2093 &ipsecerror); 2094 2095 if (sp == NULL) 2096 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2097 else { 2098 /* count IPsec header size */ 2099 ipsechdr = ipsec4_hdrsiz(mcopy, 2100 IPSEC_DIR_OUTBOUND, 2101 NULL); 2102 2103 /* 2104 * find the correct route for outer IPv4 2105 * header, compute tunnel MTU. 2106 */ 2107 2108 if (sp->req != NULL && 2109 sp->req->sav != NULL && 2110 sp->req->sav->sah != NULL) { 2111 ro = &sp->req->sav->sah->sa_route; 2112 if (ro->ro_rt != NULL && 2113 ro->ro_rt->rt_ifp != NULL) { 2114 destmtu = 2115 ro->ro_rt->rt_ifp->if_mtu; 2116 destmtu -= ipsechdr; 2117 } 2118 } 2119 2120 KEY_FREESP(&sp); 2121 } 2122 } 2123 #else /* !IPSEC && !FAST_IPSEC */ 2124 if (fwd_ro.ro_rt != NULL) 2125 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2126 #endif /*IPSEC*/ 2127 ipstat.ips_cantfrag++; 2128 break; 2129 2130 case ENOBUFS: 2131 type = ICMP_SOURCEQUENCH; 2132 code = 0; 2133 break; 2134 2135 case EACCES: /* ipfw denied packet */ 2136 panic("ip_forward EACCES should not reach"); 2137 } 2138 icmp_error(mcopy, type, code, dest, destmtu); 2139 done: 2140 if (mtemp != NULL) 2141 m_tag_delete_chain(mtemp); 2142 if (fwd_ro.ro_rt != NULL) 2143 RTFREE(fwd_ro.ro_rt); 2144 } 2145 2146 void 2147 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2148 struct mbuf *m) 2149 { 2150 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2151 struct timeval tv; 2152 2153 microtime(&tv); 2154 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2155 SCM_TIMESTAMP, SOL_SOCKET); 2156 if (*mp) 2157 mp = &(*mp)->m_next; 2158 } 2159 if (inp->inp_flags & INP_RECVDSTADDR) { 2160 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2161 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2162 if (*mp) 2163 mp = &(*mp)->m_next; 2164 } 2165 if (inp->inp_flags & INP_RECVTTL) { 2166 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2167 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2168 if (*mp) 2169 mp = &(*mp)->m_next; 2170 } 2171 #ifdef notyet 2172 /* XXX 2173 * Moving these out of udp_input() made them even more broken 2174 * than they already were. 2175 */ 2176 /* options were tossed already */ 2177 if (inp->inp_flags & INP_RECVOPTS) { 2178 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2179 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2180 if (*mp) 2181 mp = &(*mp)->m_next; 2182 } 2183 /* ip_srcroute doesn't do what we want here, need to fix */ 2184 if (inp->inp_flags & INP_RECVRETOPTS) { 2185 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 2186 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2187 if (*mp) 2188 mp = &(*mp)->m_next; 2189 } 2190 #endif 2191 if (inp->inp_flags & INP_RECVIF) { 2192 struct ifnet *ifp; 2193 struct sdlbuf { 2194 struct sockaddr_dl sdl; 2195 u_char pad[32]; 2196 } sdlbuf; 2197 struct sockaddr_dl *sdp; 2198 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2199 2200 if (((ifp = m->m_pkthdr.rcvif)) && 2201 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2202 sdp = IF_LLSOCKADDR(ifp); 2203 /* 2204 * Change our mind and don't try copy. 2205 */ 2206 if ((sdp->sdl_family != AF_LINK) || 2207 (sdp->sdl_len > sizeof(sdlbuf))) { 2208 goto makedummy; 2209 } 2210 bcopy(sdp, sdl2, sdp->sdl_len); 2211 } else { 2212 makedummy: 2213 sdl2->sdl_len = 2214 offsetof(struct sockaddr_dl, sdl_data[0]); 2215 sdl2->sdl_family = AF_LINK; 2216 sdl2->sdl_index = 0; 2217 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2218 } 2219 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2220 IP_RECVIF, IPPROTO_IP); 2221 if (*mp) 2222 mp = &(*mp)->m_next; 2223 } 2224 } 2225 2226 /* 2227 * XXX these routines are called from the upper part of the kernel. 2228 * 2229 * They could also be moved to ip_mroute.c, since all the RSVP 2230 * handling is done there already. 2231 */ 2232 int 2233 ip_rsvp_init(struct socket *so) 2234 { 2235 if (so->so_type != SOCK_RAW || 2236 so->so_proto->pr_protocol != IPPROTO_RSVP) 2237 return EOPNOTSUPP; 2238 2239 if (ip_rsvpd != NULL) 2240 return EADDRINUSE; 2241 2242 ip_rsvpd = so; 2243 /* 2244 * This may seem silly, but we need to be sure we don't over-increment 2245 * the RSVP counter, in case something slips up. 2246 */ 2247 if (!ip_rsvp_on) { 2248 ip_rsvp_on = 1; 2249 rsvp_on++; 2250 } 2251 2252 return 0; 2253 } 2254 2255 int 2256 ip_rsvp_done(void) 2257 { 2258 ip_rsvpd = NULL; 2259 /* 2260 * This may seem silly, but we need to be sure we don't over-decrement 2261 * the RSVP counter, in case something slips up. 2262 */ 2263 if (ip_rsvp_on) { 2264 ip_rsvp_on = 0; 2265 rsvp_on--; 2266 } 2267 return 0; 2268 } 2269 2270 int 2271 rsvp_input(struct mbuf **mp, int *offp, int proto) 2272 { 2273 struct mbuf *m = *mp; 2274 2275 *mp = NULL; 2276 2277 if (rsvp_input_p) { /* call the real one if loaded */ 2278 *mp = m; 2279 rsvp_input_p(mp, offp, proto); 2280 return(IPPROTO_DONE); 2281 } 2282 2283 /* Can still get packets with rsvp_on = 0 if there is a local member 2284 * of the group to which the RSVP packet is addressed. But in this 2285 * case we want to throw the packet away. 2286 */ 2287 2288 if (!rsvp_on) { 2289 m_freem(m); 2290 return(IPPROTO_DONE); 2291 } 2292 2293 if (ip_rsvpd != NULL) { 2294 *mp = m; 2295 rip_input(mp, offp, proto); 2296 return(IPPROTO_DONE); 2297 } 2298 /* Drop the packet */ 2299 m_freem(m); 2300 return(IPPROTO_DONE); 2301 } 2302