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 /* 458 * XXX handle multicast on CPU0 for now. 459 * 460 * This could happen for packets hashed by hardware 461 * using RSS, which does not differentiate multicast 462 * packets from unicast packets. 463 */ 464 m->m_pkthdr.hash = 0; 465 check_msgport = TRUE; 466 } 467 468 if (check_msgport && 469 &curthread->td_msgport != netisr_hashport(m->m_pkthdr.hash)) { 470 netisr_queue(NETISR_IP, m); 471 /* Requeued to other netisr msgport; done */ 472 return; 473 } 474 475 /* 476 * Pull out certain tags 477 */ 478 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 479 /* Next hop */ 480 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 481 KKASSERT(mtag != NULL); 482 next_hop = m_tag_data(mtag); 483 } 484 485 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 486 /* dummynet already filtered us */ 487 ip = mtod(m, struct ip *); 488 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 489 goto iphack; 490 } 491 492 ipstat.ips_total++; 493 494 /* length checks already done in ip_hashfn() */ 495 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); 496 497 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 498 ipstat.ips_badvers++; 499 goto bad; 500 } 501 502 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 503 /* length checks already done in ip_hashfn() */ 504 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 505 KASSERT(m->m_len >= hlen, ("complete IP header not in one mbuf")); 506 507 /* 127/8 must not appear on wire - RFC1122 */ 508 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 509 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 510 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 511 ipstat.ips_badaddr++; 512 goto bad; 513 } 514 } 515 516 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 517 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 518 } else { 519 if (hlen == sizeof(struct ip)) 520 sum = in_cksum_hdr(ip); 521 else 522 sum = in_cksum(m, hlen); 523 } 524 if (sum != 0) { 525 ipstat.ips_badsum++; 526 goto bad; 527 } 528 529 #ifdef ALTQ 530 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 531 /* packet is dropped by traffic conditioner */ 532 return; 533 } 534 #endif 535 /* 536 * Convert fields to host representation. 537 */ 538 ip->ip_len = ntohs(ip->ip_len); 539 ip->ip_off = ntohs(ip->ip_off); 540 541 /* length checks already done in ip_hashfn() */ 542 KASSERT(ip->ip_len >= hlen, ("total length less then header length")); 543 KASSERT(m->m_pkthdr.len >= ip->ip_len, ("mbuf too short")); 544 545 /* 546 * Trim mbufs if longer than the IP header would have us expect. 547 */ 548 if (m->m_pkthdr.len > ip->ip_len) { 549 if (m->m_len == m->m_pkthdr.len) { 550 m->m_len = ip->ip_len; 551 m->m_pkthdr.len = ip->ip_len; 552 } else { 553 m_adj(m, ip->ip_len - m->m_pkthdr.len); 554 } 555 } 556 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 557 /* 558 * Bypass packet filtering for packets from a tunnel (gif). 559 */ 560 if (ipsec_gethist(m, NULL)) 561 goto pass; 562 #endif 563 564 /* 565 * IpHack's section. 566 * Right now when no processing on packet has done 567 * and it is still fresh out of network we do our black 568 * deals with it. 569 * - Firewall: deny/allow/divert 570 * - Xlate: translate packet's addr/port (NAT). 571 * - Pipe: pass pkt through dummynet. 572 * - Wrap: fake packet's addr/port <unimpl.> 573 * - Encapsulate: put it in another IP and send out. <unimp.> 574 */ 575 576 iphack: 577 /* 578 * If we've been forwarded from the output side, then 579 * skip the firewall a second time 580 */ 581 if (next_hop != NULL) 582 goto ours; 583 584 /* No pfil hooks */ 585 if (!pfil_has_hooks(&inet_pfil_hook)) { 586 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 587 /* 588 * Strip dummynet tags from stranded packets 589 */ 590 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL); 591 KKASSERT(mtag != NULL); 592 m_tag_delete(m, mtag); 593 m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED; 594 } 595 goto pass; 596 } 597 598 /* 599 * Run through list of hooks for input packets. 600 * 601 * NOTE! If the packet is rewritten pf/ipfw/whoever must 602 * clear M_HASH. 603 */ 604 odst = ip->ip_dst; 605 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN)) 606 return; 607 if (m == NULL) /* consumed by filter */ 608 return; 609 ip = mtod(m, struct ip *); 610 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 611 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 612 613 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 614 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 615 KKASSERT(mtag != NULL); 616 next_hop = m_tag_data(mtag); 617 } 618 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 619 ip_dn_queue(m); 620 return; 621 } 622 if (m->m_pkthdr.fw_flags & FW_MBUF_REDISPATCH) { 623 m->m_pkthdr.fw_flags &= ~FW_MBUF_REDISPATCH; 624 } 625 pass: 626 /* 627 * Process options and, if not destined for us, 628 * ship it on. ip_dooptions returns 1 when an 629 * error was detected (causing an icmp message 630 * to be sent and the original packet to be freed). 631 */ 632 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, next_hop)) 633 return; 634 635 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 636 * matter if it is destined to another node, or whether it is 637 * a multicast one, RSVP wants it! and prevents it from being forwarded 638 * anywhere else. Also checks if the rsvp daemon is running before 639 * grabbing the packet. 640 */ 641 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 642 goto ours; 643 644 /* 645 * Check our list of addresses, to see if the packet is for us. 646 * If we don't have any addresses, assume any unicast packet 647 * we receive might be for us (and let the upper layers deal 648 * with it). 649 */ 650 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) && 651 !(m->m_flags & (M_MCAST | M_BCAST))) 652 goto ours; 653 654 /* 655 * Cache the destination address of the packet; this may be 656 * changed by use of 'ipfw fwd'. 657 */ 658 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 659 660 /* 661 * Enable a consistency check between the destination address 662 * and the arrival interface for a unicast packet (the RFC 1122 663 * strong ES model) if IP forwarding is disabled and the packet 664 * is not locally generated and the packet is not subject to 665 * 'ipfw fwd'. 666 * 667 * XXX - Checking also should be disabled if the destination 668 * address is ipnat'ed to a different interface. 669 * 670 * XXX - Checking is incompatible with IP aliases added 671 * to the loopback interface instead of the interface where 672 * the packets are received. 673 */ 674 checkif = ip_checkinterface && 675 !ipforwarding && 676 m->m_pkthdr.rcvif != NULL && 677 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 678 next_hop == NULL; 679 680 /* 681 * Check for exact addresses in the hash bucket. 682 */ 683 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 684 ia = iac->ia; 685 686 /* 687 * If the address matches, verify that the packet 688 * arrived via the correct interface if checking is 689 * enabled. 690 */ 691 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 692 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 693 goto ours; 694 } 695 ia = NULL; 696 697 /* 698 * Check for broadcast addresses. 699 * 700 * Only accept broadcast packets that arrive via the matching 701 * interface. Reception of forwarded directed broadcasts would 702 * be handled via ip_forward() and ether_output() with the loopback 703 * into the stack for SIMPLEX interfaces handled by ether_output(). 704 */ 705 if (m->m_pkthdr.rcvif != NULL && 706 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 707 struct ifaddr_container *ifac; 708 709 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 710 ifa_link) { 711 struct ifaddr *ifa = ifac->ifa; 712 713 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 714 continue; 715 if (ifa->ifa_addr->sa_family != AF_INET) 716 continue; 717 ia = ifatoia(ifa); 718 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 719 pkt_dst.s_addr) 720 goto ours; 721 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 722 goto ours; 723 #ifdef BOOTP_COMPAT 724 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 725 goto ours; 726 #endif 727 } 728 } 729 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 730 struct in_multi *inm; 731 732 if (ip_mrouter != NULL) { 733 /* XXX Multicast routing is not MPSAFE yet */ 734 get_mplock(); 735 736 /* 737 * If we are acting as a multicast router, all 738 * incoming multicast packets are passed to the 739 * kernel-level multicast forwarding function. 740 * The packet is returned (relatively) intact; if 741 * ip_mforward() returns a non-zero value, the packet 742 * must be discarded, else it may be accepted below. 743 */ 744 if (ip_mforward != NULL && 745 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 746 rel_mplock(); 747 ipstat.ips_cantforward++; 748 m_freem(m); 749 return; 750 } 751 752 rel_mplock(); 753 754 /* 755 * The process-level routing daemon needs to receive 756 * all multicast IGMP packets, whether or not this 757 * host belongs to their destination groups. 758 */ 759 if (ip->ip_p == IPPROTO_IGMP) 760 goto ours; 761 ipstat.ips_forward++; 762 } 763 /* 764 * See if we belong to the destination multicast group on the 765 * arrival interface. 766 */ 767 inm = IN_LOOKUP_MULTI(&ip->ip_dst, m->m_pkthdr.rcvif); 768 if (inm == NULL) { 769 ipstat.ips_notmember++; 770 m_freem(m); 771 return; 772 } 773 goto ours; 774 } 775 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 776 goto ours; 777 if (ip->ip_dst.s_addr == INADDR_ANY) 778 goto ours; 779 780 /* 781 * FAITH(Firewall Aided Internet Translator) 782 */ 783 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 784 if (ip_keepfaith) { 785 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 786 goto ours; 787 } 788 m_freem(m); 789 return; 790 } 791 792 /* 793 * Not for us; forward if possible and desirable. 794 */ 795 if (!ipforwarding) { 796 ipstat.ips_cantforward++; 797 m_freem(m); 798 } else { 799 #ifdef IPSEC 800 /* 801 * Enforce inbound IPsec SPD. 802 */ 803 if (ipsec4_in_reject(m, NULL)) { 804 ipsecstat.in_polvio++; 805 goto bad; 806 } 807 #endif 808 #ifdef FAST_IPSEC 809 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 810 crit_enter(); 811 if (mtag != NULL) { 812 tdbi = (struct tdb_ident *)m_tag_data(mtag); 813 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 814 } else { 815 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 816 IP_FORWARDING, &error); 817 } 818 if (sp == NULL) { /* NB: can happen if error */ 819 crit_exit(); 820 /*XXX error stat???*/ 821 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 822 goto bad; 823 } 824 825 /* 826 * Check security policy against packet attributes. 827 */ 828 error = ipsec_in_reject(sp, m); 829 KEY_FREESP(&sp); 830 crit_exit(); 831 if (error) { 832 ipstat.ips_cantforward++; 833 goto bad; 834 } 835 #endif 836 ip_forward(m, using_srcrt, next_hop); 837 } 838 return; 839 840 ours: 841 842 /* 843 * IPSTEALTH: Process non-routing options only 844 * if the packet is destined for us. 845 */ 846 if (ipstealth && 847 hlen > sizeof(struct ip) && 848 ip_dooptions(m, 1, next_hop)) 849 return; 850 851 /* Count the packet in the ip address stats */ 852 if (ia != NULL) { 853 IFA_STAT_INC(&ia->ia_ifa, ipackets, 1); 854 IFA_STAT_INC(&ia->ia_ifa, ibytes, m->m_pkthdr.len); 855 } 856 857 /* 858 * If offset or IP_MF are set, must reassemble. 859 * Otherwise, nothing need be done. 860 * (We could look in the reassembly queue to see 861 * if the packet was previously fragmented, 862 * but it's not worth the time; just let them time out.) 863 */ 864 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 865 /* 866 * Attempt reassembly; if it succeeds, proceed. ip_reass() 867 * will return a different mbuf. 868 * 869 * NOTE: ip_reass() returns m with M_HASH cleared to force 870 * us to recharacterize the packet. 871 */ 872 m = ip_reass(m); 873 if (m == NULL) 874 return; 875 ip = mtod(m, struct ip *); 876 877 /* Get the header length of the reassembled packet */ 878 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 879 } else { 880 ip->ip_len -= hlen; 881 } 882 883 #ifdef IPSEC 884 /* 885 * enforce IPsec policy checking if we are seeing last header. 886 * note that we do not visit this with protocols with pcb layer 887 * code - like udp/tcp/raw ip. 888 */ 889 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 890 ipsec4_in_reject(m, NULL)) { 891 ipsecstat.in_polvio++; 892 goto bad; 893 } 894 #endif 895 #if FAST_IPSEC 896 /* 897 * enforce IPsec policy checking if we are seeing last header. 898 * note that we do not visit this with protocols with pcb layer 899 * code - like udp/tcp/raw ip. 900 */ 901 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 902 /* 903 * Check if the packet has already had IPsec processing 904 * done. If so, then just pass it along. This tag gets 905 * set during AH, ESP, etc. input handling, before the 906 * packet is returned to the ip input queue for delivery. 907 */ 908 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 909 crit_enter(); 910 if (mtag != NULL) { 911 tdbi = (struct tdb_ident *)m_tag_data(mtag); 912 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 913 } else { 914 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 915 IP_FORWARDING, &error); 916 } 917 if (sp != NULL) { 918 /* 919 * Check security policy against packet attributes. 920 */ 921 error = ipsec_in_reject(sp, m); 922 KEY_FREESP(&sp); 923 } else { 924 /* XXX error stat??? */ 925 error = EINVAL; 926 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 927 goto bad; 928 } 929 crit_exit(); 930 if (error) 931 goto bad; 932 } 933 #endif /* FAST_IPSEC */ 934 935 /* 936 * We must forward the packet to the correct protocol thread if 937 * we are not already in it. 938 * 939 * NOTE: ip_len is now in host form. ip_len is not adjusted 940 * further for protocol processing, instead we pass hlen 941 * to the protosw and let it deal with it. 942 */ 943 ipstat.ips_delivered++; 944 945 if ((m->m_flags & M_HASH) == 0) { 946 #ifdef RSS_DEBUG 947 atomic_add_long(&ip_rehash_count, 1); 948 #endif 949 ip->ip_len = htons(ip->ip_len + hlen); 950 ip->ip_off = htons(ip->ip_off); 951 952 ip_hashfn(&m, 0, IP_MPORT_IN); 953 if (m == NULL) 954 return; 955 956 ip = mtod(m, struct ip *); 957 ip->ip_len = ntohs(ip->ip_len) - hlen; 958 ip->ip_off = ntohs(ip->ip_off); 959 KKASSERT(m->m_flags & M_HASH); 960 } 961 port = netisr_hashport(m->m_pkthdr.hash); 962 963 if (port != &curthread->td_msgport) { 964 struct netmsg_packet *pmsg; 965 966 #ifdef RSS_DEBUG 967 atomic_add_long(&ip_dispatch_slow, 1); 968 #endif 969 970 pmsg = &m->m_hdr.mh_netmsg; 971 netmsg_init(&pmsg->base, NULL, &netisr_apanic_rport, 972 0, transport_processing_handler); 973 pmsg->nm_packet = m; 974 pmsg->base.lmsg.u.ms_result = hlen; 975 lwkt_sendmsg(port, &pmsg->base.lmsg); 976 } else { 977 #ifdef RSS_DEBUG 978 atomic_add_long(&ip_dispatch_fast, 1); 979 #endif 980 transport_processing_oncpu(m, hlen, ip); 981 } 982 return; 983 984 bad: 985 m_freem(m); 986 } 987 988 /* 989 * Take incoming datagram fragment and try to reassemble it into 990 * whole datagram. If a chain for reassembly of this datagram already 991 * exists, then it is given as fp; otherwise have to make a chain. 992 */ 993 struct mbuf * 994 ip_reass(struct mbuf *m) 995 { 996 struct ip *ip = mtod(m, struct ip *); 997 struct mbuf *p = NULL, *q, *nq; 998 struct mbuf *n; 999 struct ipq *fp = NULL; 1000 struct ipqhead *head; 1001 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 1002 int i, next; 1003 u_short sum; 1004 1005 /* If maxnipq is 0, never accept fragments. */ 1006 if (maxnipq == 0) { 1007 ipstat.ips_fragments++; 1008 ipstat.ips_fragdropped++; 1009 m_freem(m); 1010 return NULL; 1011 } 1012 1013 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 1014 /* 1015 * Look for queue of fragments of this datagram. 1016 */ 1017 lwkt_gettoken(&ipq_token); 1018 head = &ipq[sum]; 1019 TAILQ_FOREACH(fp, head, ipq_list) { 1020 if (ip->ip_id == fp->ipq_id && 1021 ip->ip_src.s_addr == fp->ipq_src.s_addr && 1022 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 1023 ip->ip_p == fp->ipq_p) 1024 goto found; 1025 } 1026 1027 fp = NULL; 1028 1029 /* 1030 * Enforce upper bound on number of fragmented packets 1031 * for which we attempt reassembly; 1032 * If maxnipq is -1, accept all fragments without limitation. 1033 */ 1034 if (nipq > maxnipq && maxnipq > 0) { 1035 /* 1036 * drop something from the tail of the current queue 1037 * before proceeding further 1038 */ 1039 struct ipq *q = TAILQ_LAST(head, ipqhead); 1040 if (q == NULL) { 1041 /* 1042 * The current queue is empty, 1043 * so drop from one of the others. 1044 */ 1045 for (i = 0; i < IPREASS_NHASH; i++) { 1046 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 1047 if (r) { 1048 ipstat.ips_fragtimeout += r->ipq_nfrags; 1049 ip_freef(&ipq[i], r); 1050 break; 1051 } 1052 } 1053 } else { 1054 ipstat.ips_fragtimeout += q->ipq_nfrags; 1055 ip_freef(head, q); 1056 } 1057 } 1058 found: 1059 /* 1060 * Adjust ip_len to not reflect header, 1061 * convert offset of this to bytes. 1062 */ 1063 ip->ip_len -= hlen; 1064 if (ip->ip_off & IP_MF) { 1065 /* 1066 * Make sure that fragments have a data length 1067 * that's a non-zero multiple of 8 bytes. 1068 */ 1069 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 1070 ipstat.ips_toosmall++; /* XXX */ 1071 m_freem(m); 1072 goto done; 1073 } 1074 m->m_flags |= M_FRAG; 1075 } else { 1076 m->m_flags &= ~M_FRAG; 1077 } 1078 ip->ip_off <<= 3; 1079 1080 ipstat.ips_fragments++; 1081 m->m_pkthdr.header = ip; 1082 1083 /* 1084 * If the hardware has not done csum over this fragment 1085 * then csum_data is not valid at all. 1086 */ 1087 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) 1088 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) { 1089 m->m_pkthdr.csum_data = 0; 1090 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR); 1091 } 1092 1093 /* 1094 * Presence of header sizes in mbufs 1095 * would confuse code below. 1096 */ 1097 m->m_data += hlen; 1098 m->m_len -= hlen; 1099 1100 /* 1101 * If first fragment to arrive, create a reassembly queue. 1102 */ 1103 if (fp == NULL) { 1104 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1105 goto dropfrag; 1106 TAILQ_INSERT_HEAD(head, fp, ipq_list); 1107 nipq++; 1108 fp->ipq_nfrags = 1; 1109 fp->ipq_ttl = IPFRAGTTL; 1110 fp->ipq_p = ip->ip_p; 1111 fp->ipq_id = ip->ip_id; 1112 fp->ipq_src = ip->ip_src; 1113 fp->ipq_dst = ip->ip_dst; 1114 fp->ipq_frags = m; 1115 m->m_nextpkt = NULL; 1116 goto inserted; 1117 } else { 1118 fp->ipq_nfrags++; 1119 } 1120 1121 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1122 1123 /* 1124 * Find a segment which begins after this one does. 1125 */ 1126 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1127 if (GETIP(q)->ip_off > ip->ip_off) 1128 break; 1129 } 1130 1131 /* 1132 * If there is a preceding segment, it may provide some of 1133 * our data already. If so, drop the data from the incoming 1134 * segment. If it provides all of our data, drop us, otherwise 1135 * stick new segment in the proper place. 1136 * 1137 * If some of the data is dropped from the the preceding 1138 * segment, then it's checksum is invalidated. 1139 */ 1140 if (p) { 1141 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1142 if (i > 0) { 1143 if (i >= ip->ip_len) 1144 goto dropfrag; 1145 m_adj(m, i); 1146 m->m_pkthdr.csum_flags = 0; 1147 ip->ip_off += i; 1148 ip->ip_len -= i; 1149 } 1150 m->m_nextpkt = p->m_nextpkt; 1151 p->m_nextpkt = m; 1152 } else { 1153 m->m_nextpkt = fp->ipq_frags; 1154 fp->ipq_frags = m; 1155 } 1156 1157 /* 1158 * While we overlap succeeding segments trim them or, 1159 * if they are completely covered, dequeue them. 1160 */ 1161 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1162 q = nq) { 1163 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1164 if (i < GETIP(q)->ip_len) { 1165 GETIP(q)->ip_len -= i; 1166 GETIP(q)->ip_off += i; 1167 m_adj(q, i); 1168 q->m_pkthdr.csum_flags = 0; 1169 break; 1170 } 1171 nq = q->m_nextpkt; 1172 m->m_nextpkt = nq; 1173 ipstat.ips_fragdropped++; 1174 fp->ipq_nfrags--; 1175 q->m_nextpkt = NULL; 1176 m_freem(q); 1177 } 1178 1179 inserted: 1180 /* 1181 * Check for complete reassembly and perform frag per packet 1182 * limiting. 1183 * 1184 * Frag limiting is performed here so that the nth frag has 1185 * a chance to complete the packet before we drop the packet. 1186 * As a result, n+1 frags are actually allowed per packet, but 1187 * only n will ever be stored. (n = maxfragsperpacket.) 1188 * 1189 */ 1190 next = 0; 1191 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1192 if (GETIP(q)->ip_off != next) { 1193 if (fp->ipq_nfrags > maxfragsperpacket) { 1194 ipstat.ips_fragdropped += fp->ipq_nfrags; 1195 ip_freef(head, fp); 1196 } 1197 goto done; 1198 } 1199 next += GETIP(q)->ip_len; 1200 } 1201 /* Make sure the last packet didn't have the IP_MF flag */ 1202 if (p->m_flags & M_FRAG) { 1203 if (fp->ipq_nfrags > maxfragsperpacket) { 1204 ipstat.ips_fragdropped += fp->ipq_nfrags; 1205 ip_freef(head, fp); 1206 } 1207 goto done; 1208 } 1209 1210 /* 1211 * Reassembly is complete. Make sure the packet is a sane size. 1212 */ 1213 q = fp->ipq_frags; 1214 ip = GETIP(q); 1215 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1216 ipstat.ips_toolong++; 1217 ipstat.ips_fragdropped += fp->ipq_nfrags; 1218 ip_freef(head, fp); 1219 goto done; 1220 } 1221 1222 /* 1223 * Concatenate fragments. 1224 */ 1225 m = q; 1226 n = m->m_next; 1227 m->m_next = NULL; 1228 m_cat(m, n); 1229 nq = q->m_nextpkt; 1230 q->m_nextpkt = NULL; 1231 for (q = nq; q != NULL; q = nq) { 1232 nq = q->m_nextpkt; 1233 q->m_nextpkt = NULL; 1234 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1235 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1236 m_cat(m, q); 1237 } 1238 1239 /* 1240 * Clean up the 1's complement checksum. Carry over 16 bits must 1241 * be added back. This assumes no more then 65535 packet fragments 1242 * were reassembled. A second carry can also occur (but not a third). 1243 */ 1244 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + 1245 (m->m_pkthdr.csum_data >> 16); 1246 if (m->m_pkthdr.csum_data > 0xFFFF) 1247 m->m_pkthdr.csum_data -= 0xFFFF; 1248 1249 /* 1250 * Create header for new ip packet by 1251 * modifying header of first packet; 1252 * dequeue and discard fragment reassembly header. 1253 * Make header visible. 1254 */ 1255 ip->ip_len = next; 1256 ip->ip_src = fp->ipq_src; 1257 ip->ip_dst = fp->ipq_dst; 1258 TAILQ_REMOVE(head, fp, ipq_list); 1259 nipq--; 1260 mpipe_free(&ipq_mpipe, fp); 1261 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1262 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1263 /* some debugging cruft by sklower, below, will go away soon */ 1264 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1265 int plen = 0; 1266 1267 for (n = m; n; n = n->m_next) 1268 plen += n->m_len; 1269 m->m_pkthdr.len = plen; 1270 } 1271 1272 /* 1273 * Reassembly complete, return the next protocol. 1274 * 1275 * Be sure to clear M_HASH to force the packet 1276 * to be re-characterized. 1277 * 1278 * Clear M_FRAG, we are no longer a fragment. 1279 */ 1280 m->m_flags &= ~(M_HASH | M_FRAG); 1281 1282 ipstat.ips_reassembled++; 1283 lwkt_reltoken(&ipq_token); 1284 return (m); 1285 1286 dropfrag: 1287 ipstat.ips_fragdropped++; 1288 if (fp != NULL) 1289 fp->ipq_nfrags--; 1290 m_freem(m); 1291 done: 1292 lwkt_reltoken(&ipq_token); 1293 return (NULL); 1294 1295 #undef GETIP 1296 } 1297 1298 /* 1299 * Free a fragment reassembly header and all 1300 * associated datagrams. 1301 * 1302 * Called with ipq_token held. 1303 */ 1304 static void 1305 ip_freef(struct ipqhead *fhp, struct ipq *fp) 1306 { 1307 struct mbuf *q; 1308 1309 /* 1310 * Remove first to protect against blocking 1311 */ 1312 TAILQ_REMOVE(fhp, fp, ipq_list); 1313 1314 /* 1315 * Clean out at our leisure 1316 */ 1317 while (fp->ipq_frags) { 1318 q = fp->ipq_frags; 1319 fp->ipq_frags = q->m_nextpkt; 1320 q->m_nextpkt = NULL; 1321 m_freem(q); 1322 } 1323 mpipe_free(&ipq_mpipe, fp); 1324 nipq--; 1325 } 1326 1327 /* 1328 * IP timer processing; 1329 * if a timer expires on a reassembly 1330 * queue, discard it. 1331 */ 1332 void 1333 ip_slowtimo(void) 1334 { 1335 struct ipq *fp, *fp_temp; 1336 struct ipqhead *head; 1337 int i; 1338 1339 lwkt_gettoken(&ipq_token); 1340 for (i = 0; i < IPREASS_NHASH; i++) { 1341 head = &ipq[i]; 1342 TAILQ_FOREACH_MUTABLE(fp, head, ipq_list, fp_temp) { 1343 if (--fp->ipq_ttl == 0) { 1344 ipstat.ips_fragtimeout += fp->ipq_nfrags; 1345 ip_freef(head, fp); 1346 } 1347 } 1348 } 1349 /* 1350 * If we are over the maximum number of fragments 1351 * (due to the limit being lowered), drain off 1352 * enough to get down to the new limit. 1353 */ 1354 if (maxnipq >= 0 && nipq > maxnipq) { 1355 for (i = 0; i < IPREASS_NHASH; i++) { 1356 head = &ipq[i]; 1357 while (nipq > maxnipq && !TAILQ_EMPTY(head)) { 1358 ipstat.ips_fragdropped += 1359 TAILQ_FIRST(head)->ipq_nfrags; 1360 ip_freef(head, TAILQ_FIRST(head)); 1361 } 1362 } 1363 } 1364 lwkt_reltoken(&ipq_token); 1365 ipflow_slowtimo(); 1366 } 1367 1368 /* 1369 * Drain off all datagram fragments. 1370 */ 1371 void 1372 ip_drain(void) 1373 { 1374 struct ipqhead *head; 1375 int i; 1376 1377 lwkt_gettoken(&ipq_token); 1378 for (i = 0; i < IPREASS_NHASH; i++) { 1379 head = &ipq[i]; 1380 while (!TAILQ_EMPTY(head)) { 1381 ipstat.ips_fragdropped += TAILQ_FIRST(head)->ipq_nfrags; 1382 ip_freef(head, TAILQ_FIRST(head)); 1383 } 1384 } 1385 lwkt_reltoken(&ipq_token); 1386 in_rtqdrain(); 1387 } 1388 1389 /* 1390 * Do option processing on a datagram, 1391 * possibly discarding it if bad options are encountered, 1392 * or forwarding it if source-routed. 1393 * The pass argument is used when operating in the IPSTEALTH 1394 * mode to tell what options to process: 1395 * [LS]SRR (pass 0) or the others (pass 1). 1396 * The reason for as many as two passes is that when doing IPSTEALTH, 1397 * non-routing options should be processed only if the packet is for us. 1398 * Returns 1 if packet has been forwarded/freed, 1399 * 0 if the packet should be processed further. 1400 */ 1401 static int 1402 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1403 { 1404 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1405 struct ip *ip = mtod(m, struct ip *); 1406 u_char *cp; 1407 struct in_ifaddr *ia; 1408 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1409 boolean_t forward = FALSE; 1410 struct in_addr *sin, dst; 1411 n_time ntime; 1412 1413 dst = ip->ip_dst; 1414 cp = (u_char *)(ip + 1); 1415 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1416 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1417 opt = cp[IPOPT_OPTVAL]; 1418 if (opt == IPOPT_EOL) 1419 break; 1420 if (opt == IPOPT_NOP) 1421 optlen = 1; 1422 else { 1423 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1424 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1425 goto bad; 1426 } 1427 optlen = cp[IPOPT_OLEN]; 1428 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1429 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1430 goto bad; 1431 } 1432 } 1433 switch (opt) { 1434 1435 default: 1436 break; 1437 1438 /* 1439 * Source routing with record. 1440 * Find interface with current destination address. 1441 * If none on this machine then drop if strictly routed, 1442 * or do nothing if loosely routed. 1443 * Record interface address and bring up next address 1444 * component. If strictly routed make sure next 1445 * address is on directly accessible net. 1446 */ 1447 case IPOPT_LSRR: 1448 case IPOPT_SSRR: 1449 if (ipstealth && pass > 0) 1450 break; 1451 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1452 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1453 goto bad; 1454 } 1455 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1456 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1457 goto bad; 1458 } 1459 ipaddr.sin_addr = ip->ip_dst; 1460 ia = (struct in_ifaddr *) 1461 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1462 if (ia == NULL) { 1463 if (opt == IPOPT_SSRR) { 1464 type = ICMP_UNREACH; 1465 code = ICMP_UNREACH_SRCFAIL; 1466 goto bad; 1467 } 1468 if (!ip_dosourceroute) 1469 goto nosourcerouting; 1470 /* 1471 * Loose routing, and not at next destination 1472 * yet; nothing to do except forward. 1473 */ 1474 break; 1475 } 1476 off--; /* 0 origin */ 1477 if (off > optlen - (int)sizeof(struct in_addr)) { 1478 /* 1479 * End of source route. Should be for us. 1480 */ 1481 if (!ip_acceptsourceroute) 1482 goto nosourcerouting; 1483 save_rte(m, cp, ip->ip_src); 1484 break; 1485 } 1486 if (ipstealth) 1487 goto dropit; 1488 if (!ip_dosourceroute) { 1489 if (ipforwarding) { 1490 char buf[sizeof "aaa.bbb.ccc.ddd"]; 1491 1492 /* 1493 * Acting as a router, so generate ICMP 1494 */ 1495 nosourcerouting: 1496 strcpy(buf, inet_ntoa(ip->ip_dst)); 1497 log(LOG_WARNING, 1498 "attempted source route from %s to %s\n", 1499 inet_ntoa(ip->ip_src), buf); 1500 type = ICMP_UNREACH; 1501 code = ICMP_UNREACH_SRCFAIL; 1502 goto bad; 1503 } else { 1504 /* 1505 * Not acting as a router, 1506 * so silently drop. 1507 */ 1508 dropit: 1509 ipstat.ips_cantforward++; 1510 m_freem(m); 1511 return (1); 1512 } 1513 } 1514 1515 /* 1516 * locate outgoing interface 1517 */ 1518 memcpy(&ipaddr.sin_addr, cp + off, 1519 sizeof ipaddr.sin_addr); 1520 1521 if (opt == IPOPT_SSRR) { 1522 #define INA struct in_ifaddr * 1523 #define SA struct sockaddr * 1524 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1525 == NULL) 1526 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1527 } else { 1528 ia = ip_rtaddr(ipaddr.sin_addr, NULL); 1529 } 1530 if (ia == NULL) { 1531 type = ICMP_UNREACH; 1532 code = ICMP_UNREACH_SRCFAIL; 1533 goto bad; 1534 } 1535 ip->ip_dst = ipaddr.sin_addr; 1536 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1537 sizeof(struct in_addr)); 1538 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1539 /* 1540 * Let ip_intr's mcast routing check handle mcast pkts 1541 */ 1542 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1543 break; 1544 1545 case IPOPT_RR: 1546 if (ipstealth && pass == 0) 1547 break; 1548 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1549 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1550 goto bad; 1551 } 1552 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1553 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1554 goto bad; 1555 } 1556 /* 1557 * If no space remains, ignore. 1558 */ 1559 off--; /* 0 origin */ 1560 if (off > optlen - (int)sizeof(struct in_addr)) 1561 break; 1562 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1563 sizeof ipaddr.sin_addr); 1564 /* 1565 * locate outgoing interface; if we're the destination, 1566 * use the incoming interface (should be same). 1567 */ 1568 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1569 (ia = ip_rtaddr(ipaddr.sin_addr, NULL)) == NULL) { 1570 type = ICMP_UNREACH; 1571 code = ICMP_UNREACH_HOST; 1572 goto bad; 1573 } 1574 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1575 sizeof(struct in_addr)); 1576 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1577 break; 1578 1579 case IPOPT_TS: 1580 if (ipstealth && pass == 0) 1581 break; 1582 code = cp - (u_char *)ip; 1583 if (optlen < 4 || optlen > 40) { 1584 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1585 goto bad; 1586 } 1587 if ((off = cp[IPOPT_OFFSET]) < 5) { 1588 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1589 goto bad; 1590 } 1591 if (off > optlen - (int)sizeof(int32_t)) { 1592 cp[IPOPT_OFFSET + 1] += (1 << 4); 1593 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1594 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1595 goto bad; 1596 } 1597 break; 1598 } 1599 off--; /* 0 origin */ 1600 sin = (struct in_addr *)(cp + off); 1601 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1602 1603 case IPOPT_TS_TSONLY: 1604 break; 1605 1606 case IPOPT_TS_TSANDADDR: 1607 if (off + sizeof(n_time) + 1608 sizeof(struct in_addr) > optlen) { 1609 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1610 goto bad; 1611 } 1612 ipaddr.sin_addr = dst; 1613 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1614 m->m_pkthdr.rcvif); 1615 if (ia == NULL) 1616 continue; 1617 memcpy(sin, &IA_SIN(ia)->sin_addr, 1618 sizeof(struct in_addr)); 1619 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1620 off += sizeof(struct in_addr); 1621 break; 1622 1623 case IPOPT_TS_PRESPEC: 1624 if (off + sizeof(n_time) + 1625 sizeof(struct in_addr) > optlen) { 1626 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1627 goto bad; 1628 } 1629 memcpy(&ipaddr.sin_addr, sin, 1630 sizeof(struct in_addr)); 1631 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1632 continue; 1633 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1634 off += sizeof(struct in_addr); 1635 break; 1636 1637 default: 1638 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1639 goto bad; 1640 } 1641 ntime = iptime(); 1642 memcpy(cp + off, &ntime, sizeof(n_time)); 1643 cp[IPOPT_OFFSET] += sizeof(n_time); 1644 } 1645 } 1646 if (forward && ipforwarding) { 1647 ip_forward(m, TRUE, next_hop); 1648 return (1); 1649 } 1650 return (0); 1651 bad: 1652 icmp_error(m, type, code, 0, 0); 1653 ipstat.ips_badoptions++; 1654 return (1); 1655 } 1656 1657 /* 1658 * Given address of next destination (final or next hop), 1659 * return internet address info of interface to be used to get there. 1660 */ 1661 struct in_ifaddr * 1662 ip_rtaddr(struct in_addr dst, struct route *ro0) 1663 { 1664 struct route sro, *ro; 1665 struct sockaddr_in *sin; 1666 struct in_ifaddr *ia; 1667 1668 if (ro0 != NULL) { 1669 ro = ro0; 1670 } else { 1671 bzero(&sro, sizeof(sro)); 1672 ro = &sro; 1673 } 1674 1675 sin = (struct sockaddr_in *)&ro->ro_dst; 1676 1677 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1678 if (ro->ro_rt != NULL) { 1679 RTFREE(ro->ro_rt); 1680 ro->ro_rt = NULL; 1681 } 1682 sin->sin_family = AF_INET; 1683 sin->sin_len = sizeof *sin; 1684 sin->sin_addr = dst; 1685 rtalloc_ign(ro, RTF_PRCLONING); 1686 } 1687 1688 if (ro->ro_rt == NULL) 1689 return (NULL); 1690 1691 ia = ifatoia(ro->ro_rt->rt_ifa); 1692 1693 if (ro == &sro) 1694 RTFREE(ro->ro_rt); 1695 return ia; 1696 } 1697 1698 /* 1699 * Save incoming source route for use in replies, 1700 * to be picked up later by ip_srcroute if the receiver is interested. 1701 */ 1702 static void 1703 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1704 { 1705 struct m_tag *mtag; 1706 struct ip_srcrt_opt *opt; 1707 unsigned olen; 1708 1709 mtag = m_tag_get(PACKET_TAG_IPSRCRT, sizeof(*opt), MB_DONTWAIT); 1710 if (mtag == NULL) 1711 return; 1712 opt = m_tag_data(mtag); 1713 1714 olen = option[IPOPT_OLEN]; 1715 #ifdef DIAGNOSTIC 1716 if (ipprintfs) 1717 kprintf("save_rte: olen %d\n", olen); 1718 #endif 1719 if (olen > sizeof(opt->ip_srcrt) - (1 + sizeof(dst))) { 1720 m_tag_free(mtag); 1721 return; 1722 } 1723 bcopy(option, opt->ip_srcrt.srcopt, olen); 1724 opt->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1725 opt->ip_srcrt.dst = dst; 1726 m_tag_prepend(m, mtag); 1727 } 1728 1729 /* 1730 * Retrieve incoming source route for use in replies, 1731 * in the same form used by setsockopt. 1732 * The first hop is placed before the options, will be removed later. 1733 */ 1734 struct mbuf * 1735 ip_srcroute(struct mbuf *m0) 1736 { 1737 struct in_addr *p, *q; 1738 struct mbuf *m; 1739 struct m_tag *mtag; 1740 struct ip_srcrt_opt *opt; 1741 1742 if (m0 == NULL) 1743 return NULL; 1744 1745 mtag = m_tag_find(m0, PACKET_TAG_IPSRCRT, NULL); 1746 if (mtag == NULL) 1747 return NULL; 1748 opt = m_tag_data(mtag); 1749 1750 if (opt->ip_nhops == 0) 1751 return (NULL); 1752 m = m_get(MB_DONTWAIT, MT_HEADER); 1753 if (m == NULL) 1754 return (NULL); 1755 1756 #define OPTSIZ (sizeof(opt->ip_srcrt.nop) + sizeof(opt->ip_srcrt.srcopt)) 1757 1758 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1759 m->m_len = opt->ip_nhops * sizeof(struct in_addr) + 1760 sizeof(struct in_addr) + OPTSIZ; 1761 #ifdef DIAGNOSTIC 1762 if (ipprintfs) { 1763 kprintf("ip_srcroute: nhops %d mlen %d", 1764 opt->ip_nhops, m->m_len); 1765 } 1766 #endif 1767 1768 /* 1769 * First save first hop for return route 1770 */ 1771 p = &opt->ip_srcrt.route[opt->ip_nhops - 1]; 1772 *(mtod(m, struct in_addr *)) = *p--; 1773 #ifdef DIAGNOSTIC 1774 if (ipprintfs) 1775 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1776 #endif 1777 1778 /* 1779 * Copy option fields and padding (nop) to mbuf. 1780 */ 1781 opt->ip_srcrt.nop = IPOPT_NOP; 1782 opt->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1783 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &opt->ip_srcrt.nop, 1784 OPTSIZ); 1785 q = (struct in_addr *)(mtod(m, caddr_t) + 1786 sizeof(struct in_addr) + OPTSIZ); 1787 #undef OPTSIZ 1788 /* 1789 * Record return path as an IP source route, 1790 * reversing the path (pointers are now aligned). 1791 */ 1792 while (p >= opt->ip_srcrt.route) { 1793 #ifdef DIAGNOSTIC 1794 if (ipprintfs) 1795 kprintf(" %x", ntohl(q->s_addr)); 1796 #endif 1797 *q++ = *p--; 1798 } 1799 /* 1800 * Last hop goes to final destination. 1801 */ 1802 *q = opt->ip_srcrt.dst; 1803 m_tag_delete(m0, mtag); 1804 #ifdef DIAGNOSTIC 1805 if (ipprintfs) 1806 kprintf(" %x\n", ntohl(q->s_addr)); 1807 #endif 1808 return (m); 1809 } 1810 1811 /* 1812 * Strip out IP options. 1813 */ 1814 void 1815 ip_stripoptions(struct mbuf *m) 1816 { 1817 int datalen; 1818 struct ip *ip = mtod(m, struct ip *); 1819 caddr_t opts; 1820 int optlen; 1821 1822 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1823 opts = (caddr_t)(ip + 1); 1824 datalen = m->m_len - (sizeof(struct ip) + optlen); 1825 bcopy(opts + optlen, opts, datalen); 1826 m->m_len -= optlen; 1827 if (m->m_flags & M_PKTHDR) 1828 m->m_pkthdr.len -= optlen; 1829 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1830 } 1831 1832 u_char inetctlerrmap[PRC_NCMDS] = { 1833 0, 0, 0, 0, 1834 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1835 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1836 EMSGSIZE, EHOSTUNREACH, 0, 0, 1837 0, 0, 0, 0, 1838 ENOPROTOOPT, ECONNREFUSED 1839 }; 1840 1841 /* 1842 * Forward a packet. If some error occurs return the sender 1843 * an icmp packet. Note we can't always generate a meaningful 1844 * icmp message because icmp doesn't have a large enough repertoire 1845 * of codes and types. 1846 * 1847 * If not forwarding, just drop the packet. This could be confusing 1848 * if ipforwarding was zero but some routing protocol was advancing 1849 * us as a gateway to somewhere. However, we must let the routing 1850 * protocol deal with that. 1851 * 1852 * The using_srcrt parameter indicates whether the packet is being forwarded 1853 * via a source route. 1854 */ 1855 void 1856 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop) 1857 { 1858 struct ip *ip = mtod(m, struct ip *); 1859 struct rtentry *rt; 1860 struct route fwd_ro; 1861 int error, type = 0, code = 0, destmtu = 0; 1862 struct mbuf *mcopy, *mtemp = NULL; 1863 n_long dest; 1864 struct in_addr pkt_dst; 1865 1866 dest = INADDR_ANY; 1867 /* 1868 * Cache the destination address of the packet; this may be 1869 * changed by use of 'ipfw fwd'. 1870 */ 1871 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 1872 1873 #ifdef DIAGNOSTIC 1874 if (ipprintfs) 1875 kprintf("forward: src %x dst %x ttl %x\n", 1876 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1877 #endif 1878 1879 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1880 ipstat.ips_cantforward++; 1881 m_freem(m); 1882 return; 1883 } 1884 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1885 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1886 return; 1887 } 1888 1889 bzero(&fwd_ro, sizeof(fwd_ro)); 1890 ip_rtaddr(pkt_dst, &fwd_ro); 1891 if (fwd_ro.ro_rt == NULL) { 1892 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1893 return; 1894 } 1895 rt = fwd_ro.ro_rt; 1896 1897 if (curthread->td_type == TD_TYPE_NETISR) { 1898 /* 1899 * Save the IP header and at most 8 bytes of the payload, 1900 * in case we need to generate an ICMP message to the src. 1901 */ 1902 mtemp = ipforward_mtemp[mycpuid]; 1903 KASSERT((mtemp->m_flags & M_EXT) == 0 && 1904 mtemp->m_data == mtemp->m_pktdat && 1905 m_tag_first(mtemp) == NULL, 1906 ("ip_forward invalid mtemp1")); 1907 1908 if (!m_dup_pkthdr(mtemp, m, MB_DONTWAIT)) { 1909 /* 1910 * It's probably ok if the pkthdr dup fails (because 1911 * the deep copy of the tag chain failed), but for now 1912 * be conservative and just discard the copy since 1913 * code below may some day want the tags. 1914 */ 1915 mtemp = NULL; 1916 } else { 1917 mtemp->m_type = m->m_type; 1918 mtemp->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1919 (int)ip->ip_len); 1920 mtemp->m_pkthdr.len = mtemp->m_len; 1921 m_copydata(m, 0, mtemp->m_len, mtod(mtemp, caddr_t)); 1922 } 1923 } 1924 1925 if (!ipstealth) 1926 ip->ip_ttl -= IPTTLDEC; 1927 1928 /* 1929 * If forwarding packet using same interface that it came in on, 1930 * perhaps should send a redirect to sender to shortcut a hop. 1931 * Only send redirect if source is sending directly to us, 1932 * and if packet was not source routed (or has any options). 1933 * Also, don't send redirect if forwarding using a default route 1934 * or a route modified by a redirect. 1935 */ 1936 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1937 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1938 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1939 ipsendredirects && !using_srcrt && next_hop == NULL) { 1940 u_long src = ntohl(ip->ip_src.s_addr); 1941 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa; 1942 1943 if (rt_ifa != NULL && 1944 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) { 1945 if (rt->rt_flags & RTF_GATEWAY) 1946 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1947 else 1948 dest = pkt_dst.s_addr; 1949 /* 1950 * Router requirements says to only send 1951 * host redirects. 1952 */ 1953 type = ICMP_REDIRECT; 1954 code = ICMP_REDIRECT_HOST; 1955 #ifdef DIAGNOSTIC 1956 if (ipprintfs) 1957 kprintf("redirect (%d) to %x\n", code, dest); 1958 #endif 1959 } 1960 } 1961 1962 error = ip_output(m, NULL, &fwd_ro, IP_FORWARDING, NULL, NULL); 1963 if (error == 0) { 1964 ipstat.ips_forward++; 1965 if (type == 0) { 1966 if (mtemp) 1967 ipflow_create(&fwd_ro, mtemp); 1968 goto done; 1969 } else { 1970 ipstat.ips_redirectsent++; 1971 } 1972 } else { 1973 ipstat.ips_cantforward++; 1974 } 1975 1976 if (mtemp == NULL) 1977 goto done; 1978 1979 /* 1980 * Errors that do not require generating ICMP message 1981 */ 1982 switch (error) { 1983 case ENOBUFS: 1984 /* 1985 * A router should not generate ICMP_SOURCEQUENCH as 1986 * required in RFC1812 Requirements for IP Version 4 Routers. 1987 * Source quench could be a big problem under DoS attacks, 1988 * or if the underlying interface is rate-limited. 1989 * Those who need source quench packets may re-enable them 1990 * via the net.inet.ip.sendsourcequench sysctl. 1991 */ 1992 if (!ip_sendsourcequench) 1993 goto done; 1994 break; 1995 1996 case EACCES: /* ipfw denied packet */ 1997 goto done; 1998 } 1999 2000 KASSERT((mtemp->m_flags & M_EXT) == 0 && 2001 mtemp->m_data == mtemp->m_pktdat, 2002 ("ip_forward invalid mtemp2")); 2003 mcopy = m_copym(mtemp, 0, mtemp->m_len, MB_DONTWAIT); 2004 if (mcopy == NULL) 2005 goto done; 2006 2007 /* 2008 * Send ICMP message. 2009 */ 2010 switch (error) { 2011 case 0: /* forwarded, but need redirect */ 2012 /* type, code set above */ 2013 break; 2014 2015 case ENETUNREACH: /* shouldn't happen, checked above */ 2016 case EHOSTUNREACH: 2017 case ENETDOWN: 2018 case EHOSTDOWN: 2019 default: 2020 type = ICMP_UNREACH; 2021 code = ICMP_UNREACH_HOST; 2022 break; 2023 2024 case EMSGSIZE: 2025 type = ICMP_UNREACH; 2026 code = ICMP_UNREACH_NEEDFRAG; 2027 #ifdef IPSEC 2028 /* 2029 * If the packet is routed over IPsec tunnel, tell the 2030 * originator the tunnel MTU. 2031 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2032 * XXX quickhack!!! 2033 */ 2034 if (fwd_ro.ro_rt != NULL) { 2035 struct secpolicy *sp = NULL; 2036 int ipsecerror; 2037 int ipsechdr; 2038 struct route *ro; 2039 2040 sp = ipsec4_getpolicybyaddr(mcopy, 2041 IPSEC_DIR_OUTBOUND, 2042 IP_FORWARDING, 2043 &ipsecerror); 2044 2045 if (sp == NULL) 2046 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2047 else { 2048 /* count IPsec header size */ 2049 ipsechdr = ipsec4_hdrsiz(mcopy, 2050 IPSEC_DIR_OUTBOUND, 2051 NULL); 2052 2053 /* 2054 * find the correct route for outer IPv4 2055 * header, compute tunnel MTU. 2056 * 2057 */ 2058 if (sp->req != NULL && sp->req->sav != NULL && 2059 sp->req->sav->sah != NULL) { 2060 ro = &sp->req->sav->sah->sa_route; 2061 if (ro->ro_rt != NULL && 2062 ro->ro_rt->rt_ifp != NULL) { 2063 destmtu = 2064 ro->ro_rt->rt_ifp->if_mtu; 2065 destmtu -= ipsechdr; 2066 } 2067 } 2068 2069 key_freesp(sp); 2070 } 2071 } 2072 #elif FAST_IPSEC 2073 /* 2074 * If the packet is routed over IPsec tunnel, tell the 2075 * originator the tunnel MTU. 2076 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2077 * XXX quickhack!!! 2078 */ 2079 if (fwd_ro.ro_rt != NULL) { 2080 struct secpolicy *sp = NULL; 2081 int ipsecerror; 2082 int ipsechdr; 2083 struct route *ro; 2084 2085 sp = ipsec_getpolicybyaddr(mcopy, 2086 IPSEC_DIR_OUTBOUND, 2087 IP_FORWARDING, 2088 &ipsecerror); 2089 2090 if (sp == NULL) 2091 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2092 else { 2093 /* count IPsec header size */ 2094 ipsechdr = ipsec4_hdrsiz(mcopy, 2095 IPSEC_DIR_OUTBOUND, 2096 NULL); 2097 2098 /* 2099 * find the correct route for outer IPv4 2100 * header, compute tunnel MTU. 2101 */ 2102 2103 if (sp->req != NULL && 2104 sp->req->sav != NULL && 2105 sp->req->sav->sah != NULL) { 2106 ro = &sp->req->sav->sah->sa_route; 2107 if (ro->ro_rt != NULL && 2108 ro->ro_rt->rt_ifp != NULL) { 2109 destmtu = 2110 ro->ro_rt->rt_ifp->if_mtu; 2111 destmtu -= ipsechdr; 2112 } 2113 } 2114 2115 KEY_FREESP(&sp); 2116 } 2117 } 2118 #else /* !IPSEC && !FAST_IPSEC */ 2119 if (fwd_ro.ro_rt != NULL) 2120 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2121 #endif /*IPSEC*/ 2122 ipstat.ips_cantfrag++; 2123 break; 2124 2125 case ENOBUFS: 2126 type = ICMP_SOURCEQUENCH; 2127 code = 0; 2128 break; 2129 2130 case EACCES: /* ipfw denied packet */ 2131 panic("ip_forward EACCES should not reach"); 2132 } 2133 icmp_error(mcopy, type, code, dest, destmtu); 2134 done: 2135 if (mtemp != NULL) 2136 m_tag_delete_chain(mtemp); 2137 if (fwd_ro.ro_rt != NULL) 2138 RTFREE(fwd_ro.ro_rt); 2139 } 2140 2141 void 2142 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2143 struct mbuf *m) 2144 { 2145 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2146 struct timeval tv; 2147 2148 microtime(&tv); 2149 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2150 SCM_TIMESTAMP, SOL_SOCKET); 2151 if (*mp) 2152 mp = &(*mp)->m_next; 2153 } 2154 if (inp->inp_flags & INP_RECVDSTADDR) { 2155 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2156 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2157 if (*mp) 2158 mp = &(*mp)->m_next; 2159 } 2160 if (inp->inp_flags & INP_RECVTTL) { 2161 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2162 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2163 if (*mp) 2164 mp = &(*mp)->m_next; 2165 } 2166 #ifdef notyet 2167 /* XXX 2168 * Moving these out of udp_input() made them even more broken 2169 * than they already were. 2170 */ 2171 /* options were tossed already */ 2172 if (inp->inp_flags & INP_RECVOPTS) { 2173 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2174 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2175 if (*mp) 2176 mp = &(*mp)->m_next; 2177 } 2178 /* ip_srcroute doesn't do what we want here, need to fix */ 2179 if (inp->inp_flags & INP_RECVRETOPTS) { 2180 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 2181 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2182 if (*mp) 2183 mp = &(*mp)->m_next; 2184 } 2185 #endif 2186 if (inp->inp_flags & INP_RECVIF) { 2187 struct ifnet *ifp; 2188 struct sdlbuf { 2189 struct sockaddr_dl sdl; 2190 u_char pad[32]; 2191 } sdlbuf; 2192 struct sockaddr_dl *sdp; 2193 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2194 2195 if (((ifp = m->m_pkthdr.rcvif)) && 2196 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2197 sdp = IF_LLSOCKADDR(ifp); 2198 /* 2199 * Change our mind and don't try copy. 2200 */ 2201 if ((sdp->sdl_family != AF_LINK) || 2202 (sdp->sdl_len > sizeof(sdlbuf))) { 2203 goto makedummy; 2204 } 2205 bcopy(sdp, sdl2, sdp->sdl_len); 2206 } else { 2207 makedummy: 2208 sdl2->sdl_len = 2209 offsetof(struct sockaddr_dl, sdl_data[0]); 2210 sdl2->sdl_family = AF_LINK; 2211 sdl2->sdl_index = 0; 2212 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2213 } 2214 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2215 IP_RECVIF, IPPROTO_IP); 2216 if (*mp) 2217 mp = &(*mp)->m_next; 2218 } 2219 } 2220 2221 /* 2222 * XXX these routines are called from the upper part of the kernel. 2223 * 2224 * They could also be moved to ip_mroute.c, since all the RSVP 2225 * handling is done there already. 2226 */ 2227 int 2228 ip_rsvp_init(struct socket *so) 2229 { 2230 if (so->so_type != SOCK_RAW || 2231 so->so_proto->pr_protocol != IPPROTO_RSVP) 2232 return EOPNOTSUPP; 2233 2234 if (ip_rsvpd != NULL) 2235 return EADDRINUSE; 2236 2237 ip_rsvpd = so; 2238 /* 2239 * This may seem silly, but we need to be sure we don't over-increment 2240 * the RSVP counter, in case something slips up. 2241 */ 2242 if (!ip_rsvp_on) { 2243 ip_rsvp_on = 1; 2244 rsvp_on++; 2245 } 2246 2247 return 0; 2248 } 2249 2250 int 2251 ip_rsvp_done(void) 2252 { 2253 ip_rsvpd = NULL; 2254 /* 2255 * This may seem silly, but we need to be sure we don't over-decrement 2256 * the RSVP counter, in case something slips up. 2257 */ 2258 if (ip_rsvp_on) { 2259 ip_rsvp_on = 0; 2260 rsvp_on--; 2261 } 2262 return 0; 2263 } 2264 2265 int 2266 rsvp_input(struct mbuf **mp, int *offp, int proto) 2267 { 2268 struct mbuf *m = *mp; 2269 2270 *mp = NULL; 2271 2272 if (rsvp_input_p) { /* call the real one if loaded */ 2273 *mp = m; 2274 rsvp_input_p(mp, offp, proto); 2275 return(IPPROTO_DONE); 2276 } 2277 2278 /* Can still get packets with rsvp_on = 0 if there is a local member 2279 * of the group to which the RSVP packet is addressed. But in this 2280 * case we want to throw the packet away. 2281 */ 2282 2283 if (!rsvp_on) { 2284 m_freem(m); 2285 return(IPPROTO_DONE); 2286 } 2287 2288 if (ip_rsvpd != NULL) { 2289 *mp = m; 2290 rip_input(mp, offp, proto); 2291 return(IPPROTO_DONE); 2292 } 2293 /* Drop the packet */ 2294 m_freem(m); 2295 return(IPPROTO_DONE); 2296 } 2297