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