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 * $DragonFly: src/sys/netinet/ip_input.c,v 1.115 2008/10/28 07:09:26 sephe Exp $ 69 */ 70 71 #define _IP_VHL 72 73 #include "opt_bootp.h" 74 #include "opt_ipfw.h" 75 #include "opt_ipdn.h" 76 #include "opt_ipdivert.h" 77 #include "opt_ipfilter.h" 78 #include "opt_ipstealth.h" 79 #include "opt_ipsec.h" 80 81 #include <sys/param.h> 82 #include <sys/systm.h> 83 #include <sys/mbuf.h> 84 #include <sys/malloc.h> 85 #include <sys/mpipe.h> 86 #include <sys/domain.h> 87 #include <sys/protosw.h> 88 #include <sys/socket.h> 89 #include <sys/time.h> 90 #include <sys/globaldata.h> 91 #include <sys/thread.h> 92 #include <sys/kernel.h> 93 #include <sys/syslog.h> 94 #include <sys/sysctl.h> 95 #include <sys/in_cksum.h> 96 #include <sys/lock.h> 97 98 #include <sys/mplock2.h> 99 100 #include <machine/stdarg.h> 101 102 #include <net/if.h> 103 #include <net/if_types.h> 104 #include <net/if_var.h> 105 #include <net/if_dl.h> 106 #include <net/pfil.h> 107 #include <net/route.h> 108 #include <net/netisr.h> 109 110 #include <netinet/in.h> 111 #include <netinet/in_systm.h> 112 #include <netinet/in_var.h> 113 #include <netinet/ip.h> 114 #include <netinet/in_pcb.h> 115 #include <netinet/ip_var.h> 116 #include <netinet/ip_icmp.h> 117 #include <netinet/ip_divert.h> 118 #include <netinet/ip_flow.h> 119 120 #include <sys/thread2.h> 121 #include <sys/msgport2.h> 122 #include <net/netmsg2.h> 123 124 #include <sys/socketvar.h> 125 126 #include <net/ipfw/ip_fw.h> 127 #include <net/dummynet/ip_dummynet.h> 128 129 #ifdef IPSEC 130 #include <netinet6/ipsec.h> 131 #include <netproto/key/key.h> 132 #endif 133 134 #ifdef FAST_IPSEC 135 #include <netproto/ipsec/ipsec.h> 136 #include <netproto/ipsec/key.h> 137 #endif 138 139 int rsvp_on = 0; 140 static int ip_rsvp_on; 141 struct socket *ip_rsvpd; 142 143 int ip_mpsafe = 1; 144 TUNABLE_INT("net.inet.ip.mpsafe", &ip_mpsafe); 145 146 int ipforwarding = 0; 147 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 148 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 149 150 static int ipsendredirects = 1; /* XXX */ 151 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 152 &ipsendredirects, 0, "Enable sending IP redirects"); 153 154 int ip_defttl = IPDEFTTL; 155 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 156 &ip_defttl, 0, "Maximum TTL on IP packets"); 157 158 static int ip_dosourceroute = 0; 159 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 160 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 161 162 static int ip_acceptsourceroute = 0; 163 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 164 CTLFLAG_RW, &ip_acceptsourceroute, 0, 165 "Enable accepting source routed IP packets"); 166 167 static int ip_keepfaith = 0; 168 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 169 &ip_keepfaith, 0, 170 "Enable packet capture for FAITH IPv4->IPv6 translator daemon"); 171 172 static int nipq = 0; /* total # of reass queues */ 173 static int maxnipq; 174 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 175 &maxnipq, 0, 176 "Maximum number of IPv4 fragment reassembly queue entries"); 177 178 static int maxfragsperpacket; 179 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 180 &maxfragsperpacket, 0, 181 "Maximum number of IPv4 fragments allowed per packet"); 182 183 static int ip_sendsourcequench = 0; 184 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 185 &ip_sendsourcequench, 0, 186 "Enable the transmission of source quench packets"); 187 188 int ip_do_randomid = 1; 189 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 190 &ip_do_randomid, 0, 191 "Assign random ip_id values"); 192 /* 193 * XXX - Setting ip_checkinterface mostly implements the receive side of 194 * the Strong ES model described in RFC 1122, but since the routing table 195 * and transmit implementation do not implement the Strong ES model, 196 * setting this to 1 results in an odd hybrid. 197 * 198 * XXX - ip_checkinterface currently must be disabled if you use ipnat 199 * to translate the destination address to another local interface. 200 * 201 * XXX - ip_checkinterface must be disabled if you add IP aliases 202 * to the loopback interface instead of the interface where the 203 * packets for those addresses are received. 204 */ 205 static int ip_checkinterface = 0; 206 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 207 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 208 209 #ifdef DIAGNOSTIC 210 static int ipprintfs = 0; 211 #endif 212 213 extern int udp_mpsafe_proto; 214 extern int tcp_mpsafe_proto; 215 216 extern struct domain inetdomain; 217 extern struct protosw inetsw[]; 218 u_char ip_protox[IPPROTO_MAX]; 219 struct in_ifaddrhead in_ifaddrheads[MAXCPU]; /* first inet address */ 220 struct in_ifaddrhashhead *in_ifaddrhashtbls[MAXCPU]; 221 /* inet addr hash table */ 222 u_long in_ifaddrhmask; /* mask for hash table */ 223 224 struct ip_stats ipstats_percpu[MAXCPU]; 225 #ifdef SMP 226 static int 227 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 228 { 229 int cpu, error = 0; 230 231 for (cpu = 0; cpu < ncpus; ++cpu) { 232 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu], 233 sizeof(struct ip_stats)))) 234 break; 235 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu], 236 sizeof(struct ip_stats)))) 237 break; 238 } 239 240 return (error); 241 } 242 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 243 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 244 #else 245 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 246 &ipstat, ip_stats, "IP statistics"); 247 #endif 248 249 /* Packet reassembly stuff */ 250 #define IPREASS_NHASH_LOG2 6 251 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 252 #define IPREASS_HMASK (IPREASS_NHASH - 1) 253 #define IPREASS_HASH(x,y) \ 254 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 255 256 static struct ipq ipq[IPREASS_NHASH]; 257 258 #ifdef IPCTL_DEFMTU 259 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 260 &ip_mtu, 0, "Default MTU"); 261 #endif 262 263 #ifdef IPSTEALTH 264 static int ipstealth = 0; 265 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, ""); 266 #else 267 static const int ipstealth = 0; 268 #endif 269 270 struct mbuf *(*ip_divert_p)(struct mbuf *, int, int); 271 272 struct pfil_head inet_pfil_hook; 273 274 /* 275 * struct ip_srcrt_opt is used to store packet state while it travels 276 * through the stack. 277 * 278 * XXX Note that the code even makes assumptions on the size and 279 * alignment of fields inside struct ip_srcrt so e.g. adding some 280 * fields will break the code. This needs to be fixed. 281 * 282 * We need to save the IP options in case a protocol wants to respond 283 * to an incoming packet over the same route if the packet got here 284 * using IP source routing. This allows connection establishment and 285 * maintenance when the remote end is on a network that is not known 286 * to us. 287 */ 288 struct ip_srcrt { 289 struct in_addr dst; /* final destination */ 290 char nop; /* one NOP to align */ 291 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 292 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 293 }; 294 295 struct ip_srcrt_opt { 296 int ip_nhops; 297 struct ip_srcrt ip_srcrt; 298 }; 299 300 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 301 static struct malloc_pipe ipq_mpipe; 302 303 static void save_rte(struct mbuf *, u_char *, struct in_addr); 304 static int ip_dooptions(struct mbuf *m, int, struct sockaddr_in *); 305 static void ip_freef(struct ipq *); 306 static void ip_input_handler(struct netmsg *); 307 308 /* 309 * IP initialization: fill in IP protocol switch table. 310 * All protocols not implemented in kernel go to raw IP protocol handler. 311 */ 312 void 313 ip_init(void) 314 { 315 struct protosw *pr; 316 uint32_t flags; 317 int i; 318 #ifdef SMP 319 int cpu; 320 #endif 321 322 /* 323 * Make sure we can handle a reasonable number of fragments but 324 * cap it at 4000 (XXX). 325 */ 326 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 327 IFQ_MAXLEN, 4000, 0, NULL); 328 for (i = 0; i < ncpus; ++i) { 329 TAILQ_INIT(&in_ifaddrheads[i]); 330 in_ifaddrhashtbls[i] = 331 hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 332 } 333 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 334 if (pr == NULL) 335 panic("ip_init"); 336 for (i = 0; i < IPPROTO_MAX; i++) 337 ip_protox[i] = pr - inetsw; 338 for (pr = inetdomain.dom_protosw; 339 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 340 if (pr->pr_domain->dom_family == PF_INET && pr->pr_protocol) { 341 if (pr->pr_protocol != IPPROTO_RAW) 342 ip_protox[pr->pr_protocol] = pr - inetsw; 343 344 /* XXX */ 345 switch (pr->pr_protocol) { 346 case IPPROTO_TCP: 347 if (tcp_mpsafe_proto) 348 pr->pr_flags |= PR_MPSAFE; 349 break; 350 351 case IPPROTO_UDP: 352 if (udp_mpsafe_proto) 353 pr->pr_flags |= PR_MPSAFE; 354 break; 355 } 356 } 357 } 358 359 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 360 inet_pfil_hook.ph_af = AF_INET; 361 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) { 362 kprintf("%s: WARNING: unable to register pfil hook, " 363 "error %d\n", __func__, i); 364 } 365 366 for (i = 0; i < IPREASS_NHASH; i++) 367 ipq[i].next = ipq[i].prev = &ipq[i]; 368 369 maxnipq = nmbclusters / 32; 370 maxfragsperpacket = 16; 371 372 ip_id = time_second & 0xffff; 373 374 /* 375 * Initialize IP statistics counters for each CPU. 376 * 377 */ 378 #ifdef SMP 379 for (cpu = 0; cpu < ncpus; ++cpu) { 380 bzero(&ipstats_percpu[cpu], sizeof(struct ip_stats)); 381 } 382 #else 383 bzero(&ipstat, sizeof(struct ip_stats)); 384 #endif 385 386 #if defined(IPSEC) || defined(FAST_IPSEC) 387 /* XXX IPSEC is not MPSAFE yet */ 388 flags = NETISR_FLAG_NOTMPSAFE; 389 #else 390 if (ip_mpsafe) { 391 kprintf("ip: MPSAFE\n"); 392 flags = NETISR_FLAG_MPSAFE; 393 } else { 394 flags = NETISR_FLAG_NOTMPSAFE; 395 } 396 #endif 397 netisr_register(NETISR_IP, ip_mport_in, ip_mport_pktinfo, 398 ip_input_handler, flags); 399 } 400 401 /* Do transport protocol processing. */ 402 static void 403 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip) 404 { 405 const struct protosw *pr = &inetsw[ip_protox[ip->ip_p]]; 406 407 /* 408 * Switch out to protocol's input routine. 409 */ 410 PR_GET_MPLOCK(pr); 411 pr->pr_input(m, hlen, ip->ip_p); 412 PR_REL_MPLOCK(pr); 413 } 414 415 static void 416 transport_processing_handler(netmsg_t netmsg) 417 { 418 struct netmsg_packet *pmsg = (struct netmsg_packet *)netmsg; 419 struct ip *ip; 420 int hlen; 421 422 ip = mtod(pmsg->nm_packet, struct ip *); 423 hlen = pmsg->nm_netmsg.nm_lmsg.u.ms_result; 424 425 transport_processing_oncpu(pmsg->nm_packet, hlen, ip); 426 /* netmsg was embedded in the mbuf, do not reply! */ 427 } 428 429 static void 430 ip_input_handler(struct netmsg *msg0) 431 { 432 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet; 433 434 ip_input(m); 435 /* msg0 was embedded in the mbuf, do not reply! */ 436 } 437 438 /* 439 * IP input routine. Checksum and byte swap header. If fragmented 440 * try to reassemble. Process options. Pass to next level. 441 */ 442 void 443 ip_input(struct mbuf *m) 444 { 445 struct ip *ip; 446 struct in_ifaddr *ia = NULL; 447 struct in_ifaddr_container *iac; 448 int hlen, checkif; 449 u_short sum; 450 struct in_addr pkt_dst; 451 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 452 boolean_t needredispatch = FALSE; 453 struct in_addr odst; /* original dst address(NAT) */ 454 struct m_tag *mtag; 455 struct sockaddr_in *next_hop = NULL; 456 #ifdef FAST_IPSEC 457 struct tdb_ident *tdbi; 458 struct secpolicy *sp; 459 int error; 460 #endif 461 462 M_ASSERTPKTHDR(m); 463 464 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 465 /* Next hop */ 466 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 467 KKASSERT(mtag != NULL); 468 next_hop = m_tag_data(mtag); 469 } 470 471 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 472 /* dummynet already filtered us */ 473 ip = mtod(m, struct ip *); 474 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 475 goto iphack; 476 } 477 478 ipstat.ips_total++; 479 480 /* length checks already done in ip_mport() */ 481 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); 482 ip = mtod(m, struct ip *); 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_mport() */ 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_mport() */ 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 * NB: Beware of the destination address changing (e.g. 589 * by NAT rewriting). When this happens, tell 590 * ip_forward to do the right thing. 591 */ 592 odst = ip->ip_dst; 593 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN)) 594 return; 595 if (m == NULL) /* consumed by filter */ 596 return; 597 ip = mtod(m, struct ip *); 598 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 599 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 600 601 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 602 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 603 KKASSERT(mtag != NULL); 604 next_hop = m_tag_data(mtag); 605 } 606 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 607 ip_dn_queue(m); 608 return; 609 } 610 if (m->m_pkthdr.fw_flags & FW_MBUF_REDISPATCH) { 611 needredispatch = TRUE; 612 m->m_pkthdr.fw_flags &= ~FW_MBUF_REDISPATCH; 613 } 614 pass: 615 /* 616 * Process options and, if not destined for us, 617 * ship it on. ip_dooptions returns 1 when an 618 * error was detected (causing an icmp message 619 * to be sent and the original packet to be freed). 620 */ 621 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, next_hop)) 622 return; 623 624 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 625 * matter if it is destined to another node, or whether it is 626 * a multicast one, RSVP wants it! and prevents it from being forwarded 627 * anywhere else. Also checks if the rsvp daemon is running before 628 * grabbing the packet. 629 */ 630 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 631 goto ours; 632 633 /* 634 * Check our list of addresses, to see if the packet is for us. 635 * If we don't have any addresses, assume any unicast packet 636 * we receive might be for us (and let the upper layers deal 637 * with it). 638 */ 639 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) && 640 !(m->m_flags & (M_MCAST | M_BCAST))) 641 goto ours; 642 643 /* 644 * Cache the destination address of the packet; this may be 645 * changed by use of 'ipfw fwd'. 646 */ 647 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 648 649 /* 650 * Enable a consistency check between the destination address 651 * and the arrival interface for a unicast packet (the RFC 1122 652 * strong ES model) if IP forwarding is disabled and the packet 653 * is not locally generated and the packet is not subject to 654 * 'ipfw fwd'. 655 * 656 * XXX - Checking also should be disabled if the destination 657 * address is ipnat'ed to a different interface. 658 * 659 * XXX - Checking is incompatible with IP aliases added 660 * to the loopback interface instead of the interface where 661 * the packets are received. 662 */ 663 checkif = ip_checkinterface && 664 !ipforwarding && 665 m->m_pkthdr.rcvif != NULL && 666 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 667 next_hop == NULL; 668 669 /* 670 * Check for exact addresses in the hash bucket. 671 */ 672 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 673 ia = iac->ia; 674 675 /* 676 * If the address matches, verify that the packet 677 * arrived via the correct interface if checking is 678 * enabled. 679 */ 680 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 681 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 682 goto ours; 683 } 684 ia = NULL; 685 686 /* 687 * Check for broadcast addresses. 688 * 689 * Only accept broadcast packets that arrive via the matching 690 * interface. Reception of forwarded directed broadcasts would 691 * be handled via ip_forward() and ether_output() with the loopback 692 * into the stack for SIMPLEX interfaces handled by ether_output(). 693 */ 694 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 695 struct ifaddr_container *ifac; 696 697 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 698 ifa_link) { 699 struct ifaddr *ifa = ifac->ifa; 700 701 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 702 continue; 703 if (ifa->ifa_addr->sa_family != AF_INET) 704 continue; 705 ia = ifatoia(ifa); 706 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 707 pkt_dst.s_addr) 708 goto ours; 709 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 710 goto ours; 711 #ifdef BOOTP_COMPAT 712 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 713 goto ours; 714 #endif 715 } 716 } 717 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 718 struct in_multi *inm; 719 720 /* XXX Multicast is not MPSAFE yet */ 721 get_mplock(); 722 723 if (ip_mrouter != NULL) { 724 /* 725 * If we are acting as a multicast router, all 726 * incoming multicast packets are passed to the 727 * kernel-level multicast forwarding function. 728 * The packet is returned (relatively) intact; if 729 * ip_mforward() returns a non-zero value, the packet 730 * must be discarded, else it may be accepted below. 731 */ 732 if (ip_mforward != NULL && 733 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 734 rel_mplock(); 735 ipstat.ips_cantforward++; 736 m_freem(m); 737 return; 738 } 739 740 /* 741 * The process-level routing daemon needs to receive 742 * all multicast IGMP packets, whether or not this 743 * host belongs to their destination groups. 744 */ 745 if (ip->ip_p == IPPROTO_IGMP) { 746 rel_mplock(); 747 goto ours; 748 } 749 ipstat.ips_forward++; 750 } 751 /* 752 * See if we belong to the destination multicast group on the 753 * arrival interface. 754 */ 755 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 756 if (inm == NULL) { 757 rel_mplock(); 758 ipstat.ips_notmember++; 759 m_freem(m); 760 return; 761 } 762 763 rel_mplock(); 764 goto ours; 765 } 766 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 767 goto ours; 768 if (ip->ip_dst.s_addr == INADDR_ANY) 769 goto ours; 770 771 /* 772 * FAITH(Firewall Aided Internet Translator) 773 */ 774 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 775 if (ip_keepfaith) { 776 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 777 goto ours; 778 } 779 m_freem(m); 780 return; 781 } 782 783 /* 784 * Not for us; forward if possible and desirable. 785 */ 786 if (!ipforwarding) { 787 ipstat.ips_cantforward++; 788 m_freem(m); 789 } else { 790 #ifdef IPSEC 791 /* 792 * Enforce inbound IPsec SPD. 793 */ 794 if (ipsec4_in_reject(m, NULL)) { 795 ipsecstat.in_polvio++; 796 goto bad; 797 } 798 #endif 799 #ifdef FAST_IPSEC 800 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 801 crit_enter(); 802 if (mtag != NULL) { 803 tdbi = (struct tdb_ident *)m_tag_data(mtag); 804 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 805 } else { 806 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 807 IP_FORWARDING, &error); 808 } 809 if (sp == NULL) { /* NB: can happen if error */ 810 crit_exit(); 811 /*XXX error stat???*/ 812 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 813 goto bad; 814 } 815 816 /* 817 * Check security policy against packet attributes. 818 */ 819 error = ipsec_in_reject(sp, m); 820 KEY_FREESP(&sp); 821 crit_exit(); 822 if (error) { 823 ipstat.ips_cantforward++; 824 goto bad; 825 } 826 #endif 827 ip_forward(m, using_srcrt, next_hop); 828 } 829 return; 830 831 ours: 832 833 /* 834 * IPSTEALTH: Process non-routing options only 835 * if the packet is destined for us. 836 */ 837 if (ipstealth && 838 hlen > sizeof(struct ip) && 839 ip_dooptions(m, 1, next_hop)) 840 return; 841 842 /* Count the packet in the ip address stats */ 843 if (ia != NULL) { 844 ia->ia_ifa.if_ipackets++; 845 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 846 } 847 848 /* 849 * If offset or IP_MF are set, must reassemble. 850 * Otherwise, nothing need be done. 851 * (We could look in the reassembly queue to see 852 * if the packet was previously fragmented, 853 * but it's not worth the time; just let them time out.) 854 */ 855 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 856 /* 857 * Attempt reassembly; if it succeeds, proceed. 858 * ip_reass() will return a different mbuf. 859 */ 860 m = ip_reass(m); 861 if (m == NULL) 862 return; 863 ip = mtod(m, struct ip *); 864 865 /* Get the header length of the reassembled packet */ 866 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 867 868 needredispatch = TRUE; 869 } else { 870 ip->ip_len -= hlen; 871 } 872 873 #ifdef IPSEC 874 /* 875 * enforce IPsec policy checking if we are seeing last header. 876 * note that we do not visit this with protocols with pcb layer 877 * code - like udp/tcp/raw ip. 878 */ 879 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 880 ipsec4_in_reject(m, NULL)) { 881 ipsecstat.in_polvio++; 882 goto bad; 883 } 884 #endif 885 #if FAST_IPSEC 886 /* 887 * enforce IPsec policy checking if we are seeing last header. 888 * note that we do not visit this with protocols with pcb layer 889 * code - like udp/tcp/raw ip. 890 */ 891 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 892 /* 893 * Check if the packet has already had IPsec processing 894 * done. If so, then just pass it along. This tag gets 895 * set during AH, ESP, etc. input handling, before the 896 * packet is returned to the ip input queue for delivery. 897 */ 898 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 899 crit_enter(); 900 if (mtag != NULL) { 901 tdbi = (struct tdb_ident *)m_tag_data(mtag); 902 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 903 } else { 904 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 905 IP_FORWARDING, &error); 906 } 907 if (sp != NULL) { 908 /* 909 * Check security policy against packet attributes. 910 */ 911 error = ipsec_in_reject(sp, m); 912 KEY_FREESP(&sp); 913 } else { 914 /* XXX error stat??? */ 915 error = EINVAL; 916 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 917 goto bad; 918 } 919 crit_exit(); 920 if (error) 921 goto bad; 922 } 923 #endif /* FAST_IPSEC */ 924 925 /* 926 * NOTE: ip_len in host form and adjusted down by hlen for 927 * protocol processing. 928 */ 929 ipstat.ips_delivered++; 930 if (needredispatch) { 931 struct netmsg_packet *pmsg; 932 lwkt_port_t port; 933 934 ip->ip_off = htons(ip->ip_off); 935 ip->ip_len = htons(ip->ip_len + hlen); 936 port = ip_mport_in(&m); 937 if (port == NULL) 938 return; 939 940 pmsg = &m->m_hdr.mh_netmsg; 941 netmsg_init(&pmsg->nm_netmsg, NULL, &netisr_apanic_rport, 942 MSGF_MPSAFE, transport_processing_handler); 943 pmsg->nm_packet = m; 944 pmsg->nm_netmsg.nm_lmsg.u.ms_result = hlen; 945 946 ip = mtod(m, struct ip *); 947 ip->ip_len = ntohs(ip->ip_len) - hlen; 948 ip->ip_off = ntohs(ip->ip_off); 949 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg); 950 } else { 951 transport_processing_oncpu(m, hlen, ip); 952 } 953 return; 954 955 bad: 956 m_freem(m); 957 } 958 959 /* 960 * Take incoming datagram fragment and try to reassemble it into 961 * whole datagram. If a chain for reassembly of this datagram already 962 * exists, then it is given as fp; otherwise have to make a chain. 963 */ 964 struct mbuf * 965 ip_reass(struct mbuf *m) 966 { 967 struct ip *ip = mtod(m, struct ip *); 968 struct mbuf *p = NULL, *q, *nq; 969 struct mbuf *n; 970 struct ipq *fp = NULL; 971 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 972 int i, next; 973 u_short sum; 974 975 /* If maxnipq is 0, never accept fragments. */ 976 if (maxnipq == 0) { 977 ipstat.ips_fragments++; 978 ipstat.ips_fragdropped++; 979 m_freem(m); 980 return NULL; 981 } 982 983 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 984 /* 985 * Look for queue of fragments of this datagram. 986 */ 987 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 988 if (ip->ip_id == fp->ipq_id && 989 ip->ip_src.s_addr == fp->ipq_src.s_addr && 990 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 991 ip->ip_p == fp->ipq_p) 992 goto found; 993 994 fp = NULL; 995 996 /* 997 * Enforce upper bound on number of fragmented packets 998 * for which we attempt reassembly; 999 * If maxnipq is -1, accept all fragments without limitation. 1000 */ 1001 if (nipq > maxnipq && maxnipq > 0) { 1002 /* 1003 * drop something from the tail of the current queue 1004 * before proceeding further 1005 */ 1006 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 1007 for (i = 0; i < IPREASS_NHASH; i++) { 1008 if (ipq[i].prev != &ipq[i]) { 1009 ipstat.ips_fragtimeout += 1010 ipq[i].prev->ipq_nfrags; 1011 ip_freef(ipq[i].prev); 1012 break; 1013 } 1014 } 1015 } else { 1016 ipstat.ips_fragtimeout += 1017 ipq[sum].prev->ipq_nfrags; 1018 ip_freef(ipq[sum].prev); 1019 } 1020 } 1021 found: 1022 /* 1023 * Adjust ip_len to not reflect header, 1024 * convert offset of this to bytes. 1025 */ 1026 ip->ip_len -= hlen; 1027 if (ip->ip_off & IP_MF) { 1028 /* 1029 * Make sure that fragments have a data length 1030 * that's a non-zero multiple of 8 bytes. 1031 */ 1032 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 1033 ipstat.ips_toosmall++; /* XXX */ 1034 m_freem(m); 1035 return NULL; 1036 } 1037 m->m_flags |= M_FRAG; 1038 } else 1039 m->m_flags &= ~M_FRAG; 1040 ip->ip_off <<= 3; 1041 1042 ipstat.ips_fragments++; 1043 m->m_pkthdr.header = ip; 1044 1045 /* 1046 * If the hardware has not done csum over this fragment 1047 * then csum_data is not valid at all. 1048 */ 1049 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) 1050 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) { 1051 m->m_pkthdr.csum_data = 0; 1052 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR); 1053 } 1054 1055 /* 1056 * Presence of header sizes in mbufs 1057 * would confuse code below. 1058 */ 1059 m->m_data += hlen; 1060 m->m_len -= hlen; 1061 1062 /* 1063 * If first fragment to arrive, create a reassembly queue. 1064 */ 1065 if (fp == NULL) { 1066 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1067 goto dropfrag; 1068 insque(fp, &ipq[sum]); 1069 nipq++; 1070 fp->ipq_nfrags = 1; 1071 fp->ipq_ttl = IPFRAGTTL; 1072 fp->ipq_p = ip->ip_p; 1073 fp->ipq_id = ip->ip_id; 1074 fp->ipq_src = ip->ip_src; 1075 fp->ipq_dst = ip->ip_dst; 1076 fp->ipq_frags = m; 1077 m->m_nextpkt = NULL; 1078 goto inserted; 1079 } else { 1080 fp->ipq_nfrags++; 1081 } 1082 1083 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1084 1085 /* 1086 * Find a segment which begins after this one does. 1087 */ 1088 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1089 if (GETIP(q)->ip_off > ip->ip_off) 1090 break; 1091 1092 /* 1093 * If there is a preceding segment, it may provide some of 1094 * our data already. If so, drop the data from the incoming 1095 * segment. If it provides all of our data, drop us, otherwise 1096 * stick new segment in the proper place. 1097 * 1098 * If some of the data is dropped from the the preceding 1099 * segment, then it's checksum is invalidated. 1100 */ 1101 if (p) { 1102 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1103 if (i > 0) { 1104 if (i >= ip->ip_len) 1105 goto dropfrag; 1106 m_adj(m, i); 1107 m->m_pkthdr.csum_flags = 0; 1108 ip->ip_off += i; 1109 ip->ip_len -= i; 1110 } 1111 m->m_nextpkt = p->m_nextpkt; 1112 p->m_nextpkt = m; 1113 } else { 1114 m->m_nextpkt = fp->ipq_frags; 1115 fp->ipq_frags = m; 1116 } 1117 1118 /* 1119 * While we overlap succeeding segments trim them or, 1120 * if they are completely covered, dequeue them. 1121 */ 1122 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1123 q = nq) { 1124 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1125 if (i < GETIP(q)->ip_len) { 1126 GETIP(q)->ip_len -= i; 1127 GETIP(q)->ip_off += i; 1128 m_adj(q, i); 1129 q->m_pkthdr.csum_flags = 0; 1130 break; 1131 } 1132 nq = q->m_nextpkt; 1133 m->m_nextpkt = nq; 1134 ipstat.ips_fragdropped++; 1135 fp->ipq_nfrags--; 1136 q->m_nextpkt = NULL; 1137 m_freem(q); 1138 } 1139 1140 inserted: 1141 /* 1142 * Check for complete reassembly and perform frag per packet 1143 * limiting. 1144 * 1145 * Frag limiting is performed here so that the nth frag has 1146 * a chance to complete the packet before we drop the packet. 1147 * As a result, n+1 frags are actually allowed per packet, but 1148 * only n will ever be stored. (n = maxfragsperpacket.) 1149 * 1150 */ 1151 next = 0; 1152 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1153 if (GETIP(q)->ip_off != next) { 1154 if (fp->ipq_nfrags > maxfragsperpacket) { 1155 ipstat.ips_fragdropped += fp->ipq_nfrags; 1156 ip_freef(fp); 1157 } 1158 return (NULL); 1159 } 1160 next += GETIP(q)->ip_len; 1161 } 1162 /* Make sure the last packet didn't have the IP_MF flag */ 1163 if (p->m_flags & M_FRAG) { 1164 if (fp->ipq_nfrags > maxfragsperpacket) { 1165 ipstat.ips_fragdropped += fp->ipq_nfrags; 1166 ip_freef(fp); 1167 } 1168 return (NULL); 1169 } 1170 1171 /* 1172 * Reassembly is complete. Make sure the packet is a sane size. 1173 */ 1174 q = fp->ipq_frags; 1175 ip = GETIP(q); 1176 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1177 ipstat.ips_toolong++; 1178 ipstat.ips_fragdropped += fp->ipq_nfrags; 1179 ip_freef(fp); 1180 return (NULL); 1181 } 1182 1183 /* 1184 * Concatenate fragments. 1185 */ 1186 m = q; 1187 n = m->m_next; 1188 m->m_next = NULL; 1189 m_cat(m, n); 1190 nq = q->m_nextpkt; 1191 q->m_nextpkt = NULL; 1192 for (q = nq; q != NULL; q = nq) { 1193 nq = q->m_nextpkt; 1194 q->m_nextpkt = NULL; 1195 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1196 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1197 m_cat(m, q); 1198 } 1199 1200 /* 1201 * Clean up the 1's complement checksum. Carry over 16 bits must 1202 * be added back. This assumes no more then 65535 packet fragments 1203 * were reassembled. A second carry can also occur (but not a third). 1204 */ 1205 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + 1206 (m->m_pkthdr.csum_data >> 16); 1207 if (m->m_pkthdr.csum_data > 0xFFFF) 1208 m->m_pkthdr.csum_data -= 0xFFFF; 1209 1210 /* 1211 * Create header for new ip packet by 1212 * modifying header of first packet; 1213 * dequeue and discard fragment reassembly header. 1214 * Make header visible. 1215 */ 1216 ip->ip_len = next; 1217 ip->ip_src = fp->ipq_src; 1218 ip->ip_dst = fp->ipq_dst; 1219 remque(fp); 1220 nipq--; 1221 mpipe_free(&ipq_mpipe, fp); 1222 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1223 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1224 /* some debugging cruft by sklower, below, will go away soon */ 1225 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1226 int plen = 0; 1227 1228 for (n = m; n; n = n->m_next) 1229 plen += n->m_len; 1230 m->m_pkthdr.len = plen; 1231 } 1232 1233 ipstat.ips_reassembled++; 1234 return (m); 1235 1236 dropfrag: 1237 ipstat.ips_fragdropped++; 1238 if (fp != NULL) 1239 fp->ipq_nfrags--; 1240 m_freem(m); 1241 return (NULL); 1242 1243 #undef GETIP 1244 } 1245 1246 /* 1247 * Free a fragment reassembly header and all 1248 * associated datagrams. 1249 */ 1250 static void 1251 ip_freef(struct ipq *fp) 1252 { 1253 struct mbuf *q; 1254 1255 while (fp->ipq_frags) { 1256 q = fp->ipq_frags; 1257 fp->ipq_frags = q->m_nextpkt; 1258 q->m_nextpkt = NULL; 1259 m_freem(q); 1260 } 1261 remque(fp); 1262 mpipe_free(&ipq_mpipe, fp); 1263 nipq--; 1264 } 1265 1266 /* 1267 * IP timer processing; 1268 * if a timer expires on a reassembly 1269 * queue, discard it. 1270 */ 1271 void 1272 ip_slowtimo(void) 1273 { 1274 struct ipq *fp; 1275 int i; 1276 1277 crit_enter(); 1278 for (i = 0; i < IPREASS_NHASH; i++) { 1279 fp = ipq[i].next; 1280 if (fp == NULL) 1281 continue; 1282 while (fp != &ipq[i]) { 1283 --fp->ipq_ttl; 1284 fp = fp->next; 1285 if (fp->prev->ipq_ttl == 0) { 1286 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1287 ip_freef(fp->prev); 1288 } 1289 } 1290 } 1291 /* 1292 * If we are over the maximum number of fragments 1293 * (due to the limit being lowered), drain off 1294 * enough to get down to the new limit. 1295 */ 1296 if (maxnipq >= 0 && nipq > maxnipq) { 1297 for (i = 0; i < IPREASS_NHASH; i++) { 1298 while (nipq > maxnipq && 1299 (ipq[i].next != &ipq[i])) { 1300 ipstat.ips_fragdropped += 1301 ipq[i].next->ipq_nfrags; 1302 ip_freef(ipq[i].next); 1303 } 1304 } 1305 } 1306 ipflow_slowtimo(); 1307 crit_exit(); 1308 } 1309 1310 /* 1311 * Drain off all datagram fragments. 1312 */ 1313 void 1314 ip_drain(void) 1315 { 1316 int i; 1317 1318 for (i = 0; i < IPREASS_NHASH; i++) { 1319 while (ipq[i].next != &ipq[i]) { 1320 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1321 ip_freef(ipq[i].next); 1322 } 1323 } 1324 in_rtqdrain(); 1325 } 1326 1327 /* 1328 * Do option processing on a datagram, 1329 * possibly discarding it if bad options are encountered, 1330 * or forwarding it if source-routed. 1331 * The pass argument is used when operating in the IPSTEALTH 1332 * mode to tell what options to process: 1333 * [LS]SRR (pass 0) or the others (pass 1). 1334 * The reason for as many as two passes is that when doing IPSTEALTH, 1335 * non-routing options should be processed only if the packet is for us. 1336 * Returns 1 if packet has been forwarded/freed, 1337 * 0 if the packet should be processed further. 1338 */ 1339 static int 1340 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1341 { 1342 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1343 struct ip *ip = mtod(m, struct ip *); 1344 u_char *cp; 1345 struct in_ifaddr *ia; 1346 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1347 boolean_t forward = FALSE; 1348 struct in_addr *sin, dst; 1349 n_time ntime; 1350 1351 dst = ip->ip_dst; 1352 cp = (u_char *)(ip + 1); 1353 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1354 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1355 opt = cp[IPOPT_OPTVAL]; 1356 if (opt == IPOPT_EOL) 1357 break; 1358 if (opt == IPOPT_NOP) 1359 optlen = 1; 1360 else { 1361 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1362 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1363 goto bad; 1364 } 1365 optlen = cp[IPOPT_OLEN]; 1366 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1367 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1368 goto bad; 1369 } 1370 } 1371 switch (opt) { 1372 1373 default: 1374 break; 1375 1376 /* 1377 * Source routing with record. 1378 * Find interface with current destination address. 1379 * If none on this machine then drop if strictly routed, 1380 * or do nothing if loosely routed. 1381 * Record interface address and bring up next address 1382 * component. If strictly routed make sure next 1383 * address is on directly accessible net. 1384 */ 1385 case IPOPT_LSRR: 1386 case IPOPT_SSRR: 1387 if (ipstealth && pass > 0) 1388 break; 1389 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1390 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1391 goto bad; 1392 } 1393 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1394 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1395 goto bad; 1396 } 1397 ipaddr.sin_addr = ip->ip_dst; 1398 ia = (struct in_ifaddr *) 1399 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1400 if (ia == NULL) { 1401 if (opt == IPOPT_SSRR) { 1402 type = ICMP_UNREACH; 1403 code = ICMP_UNREACH_SRCFAIL; 1404 goto bad; 1405 } 1406 if (!ip_dosourceroute) 1407 goto nosourcerouting; 1408 /* 1409 * Loose routing, and not at next destination 1410 * yet; nothing to do except forward. 1411 */ 1412 break; 1413 } 1414 off--; /* 0 origin */ 1415 if (off > optlen - (int)sizeof(struct in_addr)) { 1416 /* 1417 * End of source route. Should be for us. 1418 */ 1419 if (!ip_acceptsourceroute) 1420 goto nosourcerouting; 1421 save_rte(m, cp, ip->ip_src); 1422 break; 1423 } 1424 if (ipstealth) 1425 goto dropit; 1426 if (!ip_dosourceroute) { 1427 if (ipforwarding) { 1428 char buf[sizeof "aaa.bbb.ccc.ddd"]; 1429 1430 /* 1431 * Acting as a router, so generate ICMP 1432 */ 1433 nosourcerouting: 1434 strcpy(buf, inet_ntoa(ip->ip_dst)); 1435 log(LOG_WARNING, 1436 "attempted source route from %s to %s\n", 1437 inet_ntoa(ip->ip_src), buf); 1438 type = ICMP_UNREACH; 1439 code = ICMP_UNREACH_SRCFAIL; 1440 goto bad; 1441 } else { 1442 /* 1443 * Not acting as a router, 1444 * so silently drop. 1445 */ 1446 dropit: 1447 ipstat.ips_cantforward++; 1448 m_freem(m); 1449 return (1); 1450 } 1451 } 1452 1453 /* 1454 * locate outgoing interface 1455 */ 1456 memcpy(&ipaddr.sin_addr, cp + off, 1457 sizeof ipaddr.sin_addr); 1458 1459 if (opt == IPOPT_SSRR) { 1460 #define INA struct in_ifaddr * 1461 #define SA struct sockaddr * 1462 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1463 == NULL) 1464 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1465 } else { 1466 ia = ip_rtaddr(ipaddr.sin_addr, NULL); 1467 } 1468 if (ia == NULL) { 1469 type = ICMP_UNREACH; 1470 code = ICMP_UNREACH_SRCFAIL; 1471 goto bad; 1472 } 1473 ip->ip_dst = ipaddr.sin_addr; 1474 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1475 sizeof(struct in_addr)); 1476 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1477 /* 1478 * Let ip_intr's mcast routing check handle mcast pkts 1479 */ 1480 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1481 break; 1482 1483 case IPOPT_RR: 1484 if (ipstealth && pass == 0) 1485 break; 1486 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1487 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1488 goto bad; 1489 } 1490 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1491 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1492 goto bad; 1493 } 1494 /* 1495 * If no space remains, ignore. 1496 */ 1497 off--; /* 0 origin */ 1498 if (off > optlen - (int)sizeof(struct in_addr)) 1499 break; 1500 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1501 sizeof ipaddr.sin_addr); 1502 /* 1503 * locate outgoing interface; if we're the destination, 1504 * use the incoming interface (should be same). 1505 */ 1506 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1507 (ia = ip_rtaddr(ipaddr.sin_addr, NULL)) == NULL) { 1508 type = ICMP_UNREACH; 1509 code = ICMP_UNREACH_HOST; 1510 goto bad; 1511 } 1512 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1513 sizeof(struct in_addr)); 1514 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1515 break; 1516 1517 case IPOPT_TS: 1518 if (ipstealth && pass == 0) 1519 break; 1520 code = cp - (u_char *)ip; 1521 if (optlen < 4 || optlen > 40) { 1522 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1523 goto bad; 1524 } 1525 if ((off = cp[IPOPT_OFFSET]) < 5) { 1526 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1527 goto bad; 1528 } 1529 if (off > optlen - (int)sizeof(int32_t)) { 1530 cp[IPOPT_OFFSET + 1] += (1 << 4); 1531 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1532 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1533 goto bad; 1534 } 1535 break; 1536 } 1537 off--; /* 0 origin */ 1538 sin = (struct in_addr *)(cp + off); 1539 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1540 1541 case IPOPT_TS_TSONLY: 1542 break; 1543 1544 case IPOPT_TS_TSANDADDR: 1545 if (off + sizeof(n_time) + 1546 sizeof(struct in_addr) > optlen) { 1547 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1548 goto bad; 1549 } 1550 ipaddr.sin_addr = dst; 1551 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1552 m->m_pkthdr.rcvif); 1553 if (ia == NULL) 1554 continue; 1555 memcpy(sin, &IA_SIN(ia)->sin_addr, 1556 sizeof(struct in_addr)); 1557 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1558 off += sizeof(struct in_addr); 1559 break; 1560 1561 case IPOPT_TS_PRESPEC: 1562 if (off + sizeof(n_time) + 1563 sizeof(struct in_addr) > optlen) { 1564 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1565 goto bad; 1566 } 1567 memcpy(&ipaddr.sin_addr, sin, 1568 sizeof(struct in_addr)); 1569 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1570 continue; 1571 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1572 off += sizeof(struct in_addr); 1573 break; 1574 1575 default: 1576 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1577 goto bad; 1578 } 1579 ntime = iptime(); 1580 memcpy(cp + off, &ntime, sizeof(n_time)); 1581 cp[IPOPT_OFFSET] += sizeof(n_time); 1582 } 1583 } 1584 if (forward && ipforwarding) { 1585 ip_forward(m, TRUE, next_hop); 1586 return (1); 1587 } 1588 return (0); 1589 bad: 1590 icmp_error(m, type, code, 0, 0); 1591 ipstat.ips_badoptions++; 1592 return (1); 1593 } 1594 1595 /* 1596 * Given address of next destination (final or next hop), 1597 * return internet address info of interface to be used to get there. 1598 */ 1599 struct in_ifaddr * 1600 ip_rtaddr(struct in_addr dst, struct route *ro0) 1601 { 1602 struct route sro, *ro; 1603 struct sockaddr_in *sin; 1604 struct in_ifaddr *ia; 1605 1606 if (ro0 != NULL) { 1607 ro = ro0; 1608 } else { 1609 bzero(&sro, sizeof(sro)); 1610 ro = &sro; 1611 } 1612 1613 sin = (struct sockaddr_in *)&ro->ro_dst; 1614 1615 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1616 if (ro->ro_rt != NULL) { 1617 RTFREE(ro->ro_rt); 1618 ro->ro_rt = NULL; 1619 } 1620 sin->sin_family = AF_INET; 1621 sin->sin_len = sizeof *sin; 1622 sin->sin_addr = dst; 1623 rtalloc_ign(ro, RTF_PRCLONING); 1624 } 1625 1626 if (ro->ro_rt == NULL) 1627 return (NULL); 1628 1629 ia = ifatoia(ro->ro_rt->rt_ifa); 1630 1631 if (ro == &sro) 1632 RTFREE(ro->ro_rt); 1633 return ia; 1634 } 1635 1636 /* 1637 * Save incoming source route for use in replies, 1638 * to be picked up later by ip_srcroute if the receiver is interested. 1639 */ 1640 static void 1641 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1642 { 1643 struct m_tag *mtag; 1644 struct ip_srcrt_opt *opt; 1645 unsigned olen; 1646 1647 mtag = m_tag_get(PACKET_TAG_IPSRCRT, sizeof(*opt), MB_DONTWAIT); 1648 if (mtag == NULL) 1649 return; 1650 opt = m_tag_data(mtag); 1651 1652 olen = option[IPOPT_OLEN]; 1653 #ifdef DIAGNOSTIC 1654 if (ipprintfs) 1655 kprintf("save_rte: olen %d\n", olen); 1656 #endif 1657 if (olen > sizeof(opt->ip_srcrt) - (1 + sizeof(dst))) { 1658 m_tag_free(mtag); 1659 return; 1660 } 1661 bcopy(option, opt->ip_srcrt.srcopt, olen); 1662 opt->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1663 opt->ip_srcrt.dst = dst; 1664 m_tag_prepend(m, mtag); 1665 } 1666 1667 /* 1668 * Retrieve incoming source route for use in replies, 1669 * in the same form used by setsockopt. 1670 * The first hop is placed before the options, will be removed later. 1671 */ 1672 struct mbuf * 1673 ip_srcroute(struct mbuf *m0) 1674 { 1675 struct in_addr *p, *q; 1676 struct mbuf *m; 1677 struct m_tag *mtag; 1678 struct ip_srcrt_opt *opt; 1679 1680 if (m0 == NULL) 1681 return NULL; 1682 1683 mtag = m_tag_find(m0, PACKET_TAG_IPSRCRT, NULL); 1684 if (mtag == NULL) 1685 return NULL; 1686 opt = m_tag_data(mtag); 1687 1688 if (opt->ip_nhops == 0) 1689 return (NULL); 1690 m = m_get(MB_DONTWAIT, MT_HEADER); 1691 if (m == NULL) 1692 return (NULL); 1693 1694 #define OPTSIZ (sizeof(opt->ip_srcrt.nop) + sizeof(opt->ip_srcrt.srcopt)) 1695 1696 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1697 m->m_len = opt->ip_nhops * sizeof(struct in_addr) + 1698 sizeof(struct in_addr) + OPTSIZ; 1699 #ifdef DIAGNOSTIC 1700 if (ipprintfs) { 1701 kprintf("ip_srcroute: nhops %d mlen %d", 1702 opt->ip_nhops, m->m_len); 1703 } 1704 #endif 1705 1706 /* 1707 * First save first hop for return route 1708 */ 1709 p = &opt->ip_srcrt.route[opt->ip_nhops - 1]; 1710 *(mtod(m, struct in_addr *)) = *p--; 1711 #ifdef DIAGNOSTIC 1712 if (ipprintfs) 1713 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1714 #endif 1715 1716 /* 1717 * Copy option fields and padding (nop) to mbuf. 1718 */ 1719 opt->ip_srcrt.nop = IPOPT_NOP; 1720 opt->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1721 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &opt->ip_srcrt.nop, 1722 OPTSIZ); 1723 q = (struct in_addr *)(mtod(m, caddr_t) + 1724 sizeof(struct in_addr) + OPTSIZ); 1725 #undef OPTSIZ 1726 /* 1727 * Record return path as an IP source route, 1728 * reversing the path (pointers are now aligned). 1729 */ 1730 while (p >= opt->ip_srcrt.route) { 1731 #ifdef DIAGNOSTIC 1732 if (ipprintfs) 1733 kprintf(" %x", ntohl(q->s_addr)); 1734 #endif 1735 *q++ = *p--; 1736 } 1737 /* 1738 * Last hop goes to final destination. 1739 */ 1740 *q = opt->ip_srcrt.dst; 1741 m_tag_delete(m0, mtag); 1742 #ifdef DIAGNOSTIC 1743 if (ipprintfs) 1744 kprintf(" %x\n", ntohl(q->s_addr)); 1745 #endif 1746 return (m); 1747 } 1748 1749 /* 1750 * Strip out IP options. 1751 */ 1752 void 1753 ip_stripoptions(struct mbuf *m) 1754 { 1755 int datalen; 1756 struct ip *ip = mtod(m, struct ip *); 1757 caddr_t opts; 1758 int optlen; 1759 1760 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1761 opts = (caddr_t)(ip + 1); 1762 datalen = m->m_len - (sizeof(struct ip) + optlen); 1763 bcopy(opts + optlen, opts, datalen); 1764 m->m_len -= optlen; 1765 if (m->m_flags & M_PKTHDR) 1766 m->m_pkthdr.len -= optlen; 1767 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1768 } 1769 1770 u_char inetctlerrmap[PRC_NCMDS] = { 1771 0, 0, 0, 0, 1772 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1773 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1774 EMSGSIZE, EHOSTUNREACH, 0, 0, 1775 0, 0, 0, 0, 1776 ENOPROTOOPT, ECONNREFUSED 1777 }; 1778 1779 /* 1780 * Forward a packet. If some error occurs return the sender 1781 * an icmp packet. Note we can't always generate a meaningful 1782 * icmp message because icmp doesn't have a large enough repertoire 1783 * of codes and types. 1784 * 1785 * If not forwarding, just drop the packet. This could be confusing 1786 * if ipforwarding was zero but some routing protocol was advancing 1787 * us as a gateway to somewhere. However, we must let the routing 1788 * protocol deal with that. 1789 * 1790 * The using_srcrt parameter indicates whether the packet is being forwarded 1791 * via a source route. 1792 */ 1793 void 1794 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop) 1795 { 1796 struct ip *ip = mtod(m, struct ip *); 1797 struct rtentry *rt; 1798 struct route fwd_ro; 1799 int error, type = 0, code = 0, destmtu = 0; 1800 struct mbuf *mcopy; 1801 n_long dest; 1802 struct in_addr pkt_dst; 1803 1804 dest = INADDR_ANY; 1805 /* 1806 * Cache the destination address of the packet; this may be 1807 * changed by use of 'ipfw fwd'. 1808 */ 1809 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 1810 1811 #ifdef DIAGNOSTIC 1812 if (ipprintfs) 1813 kprintf("forward: src %x dst %x ttl %x\n", 1814 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1815 #endif 1816 1817 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1818 ipstat.ips_cantforward++; 1819 m_freem(m); 1820 return; 1821 } 1822 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1823 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1824 return; 1825 } 1826 1827 bzero(&fwd_ro, sizeof(fwd_ro)); 1828 ip_rtaddr(pkt_dst, &fwd_ro); 1829 if (fwd_ro.ro_rt == NULL) { 1830 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1831 return; 1832 } 1833 rt = fwd_ro.ro_rt; 1834 1835 /* 1836 * Save the IP header and at most 8 bytes of the payload, 1837 * in case we need to generate an ICMP message to the src. 1838 * 1839 * XXX this can be optimized a lot by saving the data in a local 1840 * buffer on the stack (72 bytes at most), and only allocating the 1841 * mbuf if really necessary. The vast majority of the packets 1842 * are forwarded without having to send an ICMP back (either 1843 * because unnecessary, or because rate limited), so we are 1844 * really we are wasting a lot of work here. 1845 * 1846 * We don't use m_copy() because it might return a reference 1847 * to a shared cluster. Both this function and ip_output() 1848 * assume exclusive access to the IP header in `m', so any 1849 * data in a cluster may change before we reach icmp_error(). 1850 */ 1851 MGETHDR(mcopy, MB_DONTWAIT, m->m_type); 1852 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) { 1853 /* 1854 * It's probably ok if the pkthdr dup fails (because 1855 * the deep copy of the tag chain failed), but for now 1856 * be conservative and just discard the copy since 1857 * code below may some day want the tags. 1858 */ 1859 m_free(mcopy); 1860 mcopy = NULL; 1861 } 1862 if (mcopy != NULL) { 1863 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1864 (int)ip->ip_len); 1865 mcopy->m_pkthdr.len = mcopy->m_len; 1866 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1867 } 1868 1869 if (!ipstealth) 1870 ip->ip_ttl -= IPTTLDEC; 1871 1872 /* 1873 * If forwarding packet using same interface that it came in on, 1874 * perhaps should send a redirect to sender to shortcut a hop. 1875 * Only send redirect if source is sending directly to us, 1876 * and if packet was not source routed (or has any options). 1877 * Also, don't send redirect if forwarding using a default route 1878 * or a route modified by a redirect. 1879 */ 1880 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1881 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1882 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1883 ipsendredirects && !using_srcrt && next_hop == NULL) { 1884 u_long src = ntohl(ip->ip_src.s_addr); 1885 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa; 1886 1887 if (rt_ifa != NULL && 1888 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) { 1889 if (rt->rt_flags & RTF_GATEWAY) 1890 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1891 else 1892 dest = pkt_dst.s_addr; 1893 /* 1894 * Router requirements says to only send 1895 * host redirects. 1896 */ 1897 type = ICMP_REDIRECT; 1898 code = ICMP_REDIRECT_HOST; 1899 #ifdef DIAGNOSTIC 1900 if (ipprintfs) 1901 kprintf("redirect (%d) to %x\n", code, dest); 1902 #endif 1903 } 1904 } 1905 1906 error = ip_output(m, NULL, &fwd_ro, IP_FORWARDING, NULL, NULL); 1907 if (error == 0) { 1908 ipstat.ips_forward++; 1909 if (type == 0) { 1910 if (mcopy) { 1911 ipflow_create(&fwd_ro, mcopy); 1912 m_freem(mcopy); 1913 } 1914 goto done; 1915 } else { 1916 ipstat.ips_redirectsent++; 1917 } 1918 } else { 1919 ipstat.ips_cantforward++; 1920 } 1921 1922 if (mcopy == NULL) 1923 goto done; 1924 1925 /* 1926 * Send ICMP message. 1927 */ 1928 1929 switch (error) { 1930 1931 case 0: /* forwarded, but need redirect */ 1932 /* type, code set above */ 1933 break; 1934 1935 case ENETUNREACH: /* shouldn't happen, checked above */ 1936 case EHOSTUNREACH: 1937 case ENETDOWN: 1938 case EHOSTDOWN: 1939 default: 1940 type = ICMP_UNREACH; 1941 code = ICMP_UNREACH_HOST; 1942 break; 1943 1944 case EMSGSIZE: 1945 type = ICMP_UNREACH; 1946 code = ICMP_UNREACH_NEEDFRAG; 1947 #ifdef IPSEC 1948 /* 1949 * If the packet is routed over IPsec tunnel, tell the 1950 * originator the tunnel MTU. 1951 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1952 * XXX quickhack!!! 1953 */ 1954 if (fwd_ro.ro_rt != NULL) { 1955 struct secpolicy *sp = NULL; 1956 int ipsecerror; 1957 int ipsechdr; 1958 struct route *ro; 1959 1960 sp = ipsec4_getpolicybyaddr(mcopy, 1961 IPSEC_DIR_OUTBOUND, 1962 IP_FORWARDING, 1963 &ipsecerror); 1964 1965 if (sp == NULL) 1966 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 1967 else { 1968 /* count IPsec header size */ 1969 ipsechdr = ipsec4_hdrsiz(mcopy, 1970 IPSEC_DIR_OUTBOUND, 1971 NULL); 1972 1973 /* 1974 * find the correct route for outer IPv4 1975 * header, compute tunnel MTU. 1976 * 1977 */ 1978 if (sp->req != NULL && sp->req->sav != NULL && 1979 sp->req->sav->sah != NULL) { 1980 ro = &sp->req->sav->sah->sa_route; 1981 if (ro->ro_rt != NULL && 1982 ro->ro_rt->rt_ifp != NULL) { 1983 destmtu = 1984 ro->ro_rt->rt_ifp->if_mtu; 1985 destmtu -= ipsechdr; 1986 } 1987 } 1988 1989 key_freesp(sp); 1990 } 1991 } 1992 #elif FAST_IPSEC 1993 /* 1994 * If the packet is routed over IPsec tunnel, tell the 1995 * originator the tunnel MTU. 1996 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1997 * XXX quickhack!!! 1998 */ 1999 if (fwd_ro.ro_rt != NULL) { 2000 struct secpolicy *sp = NULL; 2001 int ipsecerror; 2002 int ipsechdr; 2003 struct route *ro; 2004 2005 sp = ipsec_getpolicybyaddr(mcopy, 2006 IPSEC_DIR_OUTBOUND, 2007 IP_FORWARDING, 2008 &ipsecerror); 2009 2010 if (sp == NULL) 2011 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2012 else { 2013 /* count IPsec header size */ 2014 ipsechdr = ipsec4_hdrsiz(mcopy, 2015 IPSEC_DIR_OUTBOUND, 2016 NULL); 2017 2018 /* 2019 * find the correct route for outer IPv4 2020 * header, compute tunnel MTU. 2021 */ 2022 2023 if (sp->req != NULL && 2024 sp->req->sav != NULL && 2025 sp->req->sav->sah != NULL) { 2026 ro = &sp->req->sav->sah->sa_route; 2027 if (ro->ro_rt != NULL && 2028 ro->ro_rt->rt_ifp != NULL) { 2029 destmtu = 2030 ro->ro_rt->rt_ifp->if_mtu; 2031 destmtu -= ipsechdr; 2032 } 2033 } 2034 2035 KEY_FREESP(&sp); 2036 } 2037 } 2038 #else /* !IPSEC && !FAST_IPSEC */ 2039 if (fwd_ro.ro_rt != NULL) 2040 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2041 #endif /*IPSEC*/ 2042 ipstat.ips_cantfrag++; 2043 break; 2044 2045 case ENOBUFS: 2046 /* 2047 * A router should not generate ICMP_SOURCEQUENCH as 2048 * required in RFC1812 Requirements for IP Version 4 Routers. 2049 * Source quench could be a big problem under DoS attacks, 2050 * or if the underlying interface is rate-limited. 2051 * Those who need source quench packets may re-enable them 2052 * via the net.inet.ip.sendsourcequench sysctl. 2053 */ 2054 if (!ip_sendsourcequench) { 2055 m_freem(mcopy); 2056 goto done; 2057 } else { 2058 type = ICMP_SOURCEQUENCH; 2059 code = 0; 2060 } 2061 break; 2062 2063 case EACCES: /* ipfw denied packet */ 2064 m_freem(mcopy); 2065 goto done; 2066 } 2067 icmp_error(mcopy, type, code, dest, destmtu); 2068 done: 2069 if (fwd_ro.ro_rt != NULL) 2070 RTFREE(fwd_ro.ro_rt); 2071 } 2072 2073 void 2074 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2075 struct mbuf *m) 2076 { 2077 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2078 struct timeval tv; 2079 2080 microtime(&tv); 2081 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2082 SCM_TIMESTAMP, SOL_SOCKET); 2083 if (*mp) 2084 mp = &(*mp)->m_next; 2085 } 2086 if (inp->inp_flags & INP_RECVDSTADDR) { 2087 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2088 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2089 if (*mp) 2090 mp = &(*mp)->m_next; 2091 } 2092 if (inp->inp_flags & INP_RECVTTL) { 2093 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2094 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2095 if (*mp) 2096 mp = &(*mp)->m_next; 2097 } 2098 #ifdef notyet 2099 /* XXX 2100 * Moving these out of udp_input() made them even more broken 2101 * than they already were. 2102 */ 2103 /* options were tossed already */ 2104 if (inp->inp_flags & INP_RECVOPTS) { 2105 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2106 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2107 if (*mp) 2108 mp = &(*mp)->m_next; 2109 } 2110 /* ip_srcroute doesn't do what we want here, need to fix */ 2111 if (inp->inp_flags & INP_RECVRETOPTS) { 2112 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 2113 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2114 if (*mp) 2115 mp = &(*mp)->m_next; 2116 } 2117 #endif 2118 if (inp->inp_flags & INP_RECVIF) { 2119 struct ifnet *ifp; 2120 struct sdlbuf { 2121 struct sockaddr_dl sdl; 2122 u_char pad[32]; 2123 } sdlbuf; 2124 struct sockaddr_dl *sdp; 2125 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2126 2127 if (((ifp = m->m_pkthdr.rcvif)) && 2128 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2129 sdp = IF_LLSOCKADDR(ifp); 2130 /* 2131 * Change our mind and don't try copy. 2132 */ 2133 if ((sdp->sdl_family != AF_LINK) || 2134 (sdp->sdl_len > sizeof(sdlbuf))) { 2135 goto makedummy; 2136 } 2137 bcopy(sdp, sdl2, sdp->sdl_len); 2138 } else { 2139 makedummy: 2140 sdl2->sdl_len = 2141 offsetof(struct sockaddr_dl, sdl_data[0]); 2142 sdl2->sdl_family = AF_LINK; 2143 sdl2->sdl_index = 0; 2144 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2145 } 2146 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2147 IP_RECVIF, IPPROTO_IP); 2148 if (*mp) 2149 mp = &(*mp)->m_next; 2150 } 2151 } 2152 2153 /* 2154 * XXX these routines are called from the upper part of the kernel. 2155 * 2156 * They could also be moved to ip_mroute.c, since all the RSVP 2157 * handling is done there already. 2158 */ 2159 int 2160 ip_rsvp_init(struct socket *so) 2161 { 2162 if (so->so_type != SOCK_RAW || 2163 so->so_proto->pr_protocol != IPPROTO_RSVP) 2164 return EOPNOTSUPP; 2165 2166 if (ip_rsvpd != NULL) 2167 return EADDRINUSE; 2168 2169 ip_rsvpd = so; 2170 /* 2171 * This may seem silly, but we need to be sure we don't over-increment 2172 * the RSVP counter, in case something slips up. 2173 */ 2174 if (!ip_rsvp_on) { 2175 ip_rsvp_on = 1; 2176 rsvp_on++; 2177 } 2178 2179 return 0; 2180 } 2181 2182 int 2183 ip_rsvp_done(void) 2184 { 2185 ip_rsvpd = NULL; 2186 /* 2187 * This may seem silly, but we need to be sure we don't over-decrement 2188 * the RSVP counter, in case something slips up. 2189 */ 2190 if (ip_rsvp_on) { 2191 ip_rsvp_on = 0; 2192 rsvp_on--; 2193 } 2194 return 0; 2195 } 2196 2197 void 2198 rsvp_input(struct mbuf *m, ...) /* XXX must fixup manually */ 2199 { 2200 int off, proto; 2201 __va_list ap; 2202 2203 __va_start(ap, m); 2204 off = __va_arg(ap, int); 2205 proto = __va_arg(ap, int); 2206 __va_end(ap); 2207 2208 if (rsvp_input_p) { /* call the real one if loaded */ 2209 rsvp_input_p(m, off, proto); 2210 return; 2211 } 2212 2213 /* Can still get packets with rsvp_on = 0 if there is a local member 2214 * of the group to which the RSVP packet is addressed. But in this 2215 * case we want to throw the packet away. 2216 */ 2217 2218 if (!rsvp_on) { 2219 m_freem(m); 2220 return; 2221 } 2222 2223 if (ip_rsvpd != NULL) { 2224 rip_input(m, off, proto); 2225 return; 2226 } 2227 /* Drop the packet */ 2228 m_freem(m); 2229 } 2230