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 <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 ip_mpsafe = 1; 142 TUNABLE_INT("net.inet.ip.mpsafe", &ip_mpsafe); 143 144 int ipforwarding = 0; 145 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 146 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 147 148 static int ipsendredirects = 1; /* XXX */ 149 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 150 &ipsendredirects, 0, "Enable sending IP redirects"); 151 152 int ip_defttl = IPDEFTTL; 153 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 154 &ip_defttl, 0, "Maximum TTL on IP packets"); 155 156 static int ip_dosourceroute = 0; 157 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 158 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 159 160 static int ip_acceptsourceroute = 0; 161 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 162 CTLFLAG_RW, &ip_acceptsourceroute, 0, 163 "Enable accepting source routed IP packets"); 164 165 static int ip_keepfaith = 0; 166 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 167 &ip_keepfaith, 0, 168 "Enable packet capture for FAITH IPv4->IPv6 translator daemon"); 169 170 static int nipq = 0; /* total # of reass queues */ 171 static int maxnipq; 172 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 173 &maxnipq, 0, 174 "Maximum number of IPv4 fragment reassembly queue entries"); 175 176 static int maxfragsperpacket; 177 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 178 &maxfragsperpacket, 0, 179 "Maximum number of IPv4 fragments allowed per packet"); 180 181 static int ip_sendsourcequench = 0; 182 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 183 &ip_sendsourcequench, 0, 184 "Enable the transmission of source quench packets"); 185 186 int ip_do_randomid = 1; 187 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 188 &ip_do_randomid, 0, 189 "Assign random ip_id values"); 190 /* 191 * XXX - Setting ip_checkinterface mostly implements the receive side of 192 * the Strong ES model described in RFC 1122, but since the routing table 193 * and transmit implementation do not implement the Strong ES model, 194 * setting this to 1 results in an odd hybrid. 195 * 196 * XXX - ip_checkinterface currently must be disabled if you use ipnat 197 * to translate the destination address to another local interface. 198 * 199 * XXX - ip_checkinterface must be disabled if you add IP aliases 200 * to the loopback interface instead of the interface where the 201 * packets for those addresses are received. 202 */ 203 static int ip_checkinterface = 0; 204 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 205 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 206 207 #ifdef DIAGNOSTIC 208 static int ipprintfs = 0; 209 #endif 210 211 extern int udp_mpsafe_proto; 212 extern int tcp_mpsafe_proto; 213 214 extern struct domain inetdomain; 215 extern struct protosw inetsw[]; 216 u_char ip_protox[IPPROTO_MAX]; 217 struct in_ifaddrhead in_ifaddrheads[MAXCPU]; /* first inet address */ 218 struct in_ifaddrhashhead *in_ifaddrhashtbls[MAXCPU]; 219 /* inet addr hash table */ 220 u_long in_ifaddrhmask; /* mask for hash table */ 221 222 struct ip_stats ipstats_percpu[MAXCPU]; 223 #ifdef SMP 224 static int 225 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 226 { 227 int cpu, error = 0; 228 229 for (cpu = 0; cpu < ncpus; ++cpu) { 230 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu], 231 sizeof(struct ip_stats)))) 232 break; 233 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu], 234 sizeof(struct ip_stats)))) 235 break; 236 } 237 238 return (error); 239 } 240 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 241 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 242 #else 243 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 244 &ipstat, ip_stats, "IP statistics"); 245 #endif 246 247 /* Packet reassembly stuff */ 248 #define IPREASS_NHASH_LOG2 6 249 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 250 #define IPREASS_HMASK (IPREASS_NHASH - 1) 251 #define IPREASS_HASH(x,y) \ 252 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 253 254 static struct ipq ipq[IPREASS_NHASH]; 255 256 #ifdef IPCTL_DEFMTU 257 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 258 &ip_mtu, 0, "Default MTU"); 259 #endif 260 261 #ifdef IPSTEALTH 262 static int ipstealth = 0; 263 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, ""); 264 #else 265 static const int ipstealth = 0; 266 #endif 267 268 struct mbuf *(*ip_divert_p)(struct mbuf *, int, int); 269 270 struct pfil_head inet_pfil_hook; 271 272 /* 273 * struct ip_srcrt_opt is used to store packet state while it travels 274 * through the stack. 275 * 276 * XXX Note that the code even makes assumptions on the size and 277 * alignment of fields inside struct ip_srcrt so e.g. adding some 278 * fields will break the code. This needs to be fixed. 279 * 280 * We need to save the IP options in case a protocol wants to respond 281 * to an incoming packet over the same route if the packet got here 282 * using IP source routing. This allows connection establishment and 283 * maintenance when the remote end is on a network that is not known 284 * to us. 285 */ 286 struct ip_srcrt { 287 struct in_addr dst; /* final destination */ 288 char nop; /* one NOP to align */ 289 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 290 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 291 }; 292 293 struct ip_srcrt_opt { 294 int ip_nhops; 295 struct ip_srcrt ip_srcrt; 296 }; 297 298 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 299 static struct malloc_pipe ipq_mpipe; 300 301 static void save_rte(struct mbuf *, u_char *, struct in_addr); 302 static int ip_dooptions(struct mbuf *m, int, struct sockaddr_in *); 303 static void ip_freef(struct ipq *); 304 static void ip_input_handler(struct netmsg *); 305 306 /* 307 * IP initialization: fill in IP protocol switch table. 308 * All protocols not implemented in kernel go to raw IP protocol handler. 309 */ 310 void 311 ip_init(void) 312 { 313 struct protosw *pr; 314 uint32_t flags; 315 int i; 316 #ifdef SMP 317 int cpu; 318 #endif 319 320 /* 321 * Make sure we can handle a reasonable number of fragments but 322 * cap it at 4000 (XXX). 323 */ 324 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 325 IFQ_MAXLEN, 4000, 0, NULL); 326 for (i = 0; i < ncpus; ++i) { 327 TAILQ_INIT(&in_ifaddrheads[i]); 328 in_ifaddrhashtbls[i] = 329 hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 330 } 331 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 332 if (pr == NULL) 333 panic("ip_init"); 334 for (i = 0; i < IPPROTO_MAX; i++) 335 ip_protox[i] = pr - inetsw; 336 for (pr = inetdomain.dom_protosw; 337 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 338 if (pr->pr_domain->dom_family == PF_INET && pr->pr_protocol) { 339 if (pr->pr_protocol != IPPROTO_RAW) 340 ip_protox[pr->pr_protocol] = pr - inetsw; 341 342 /* XXX */ 343 switch (pr->pr_protocol) { 344 case IPPROTO_TCP: 345 if (tcp_mpsafe_proto) 346 pr->pr_flags |= PR_MPSAFE; 347 break; 348 349 case IPPROTO_UDP: 350 if (udp_mpsafe_proto) 351 pr->pr_flags |= PR_MPSAFE; 352 break; 353 } 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 ipq[i].next = ipq[i].prev = &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 #if defined(IPSEC) || defined(FAST_IPSEC) 385 /* XXX IPSEC is not MPSAFE yet */ 386 flags = NETISR_FLAG_NOTMPSAFE; 387 #else 388 if (ip_mpsafe) { 389 kprintf("ip: MPSAFE\n"); 390 flags = NETISR_FLAG_MPSAFE; 391 } else { 392 flags = NETISR_FLAG_NOTMPSAFE; 393 } 394 #endif 395 netisr_register(NETISR_IP, ip_mport_in, pktinfo_portfn_notsupp, 396 ip_input_handler, flags); 397 } 398 399 /* 400 * XXX watch out this one. It is perhaps used as a cache for 401 * the most recently used route ? it is cleared in in_addroute() 402 * when a new route is successfully created. 403 */ 404 struct route ipforward_rt[MAXCPU]; 405 406 /* Do transport protocol processing. */ 407 static void 408 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip) 409 { 410 const struct protosw *pr = &inetsw[ip_protox[ip->ip_p]]; 411 412 /* 413 * Switch out to protocol's input routine. 414 */ 415 PR_GET_MPLOCK(pr); 416 pr->pr_input(m, hlen, ip->ip_p); 417 PR_REL_MPLOCK(pr); 418 } 419 420 static void 421 transport_processing_handler(netmsg_t netmsg) 422 { 423 struct netmsg_packet *pmsg = (struct netmsg_packet *)netmsg; 424 struct ip *ip; 425 int hlen; 426 427 ip = mtod(pmsg->nm_packet, struct ip *); 428 hlen = pmsg->nm_netmsg.nm_lmsg.u.ms_result; 429 430 transport_processing_oncpu(pmsg->nm_packet, hlen, ip); 431 /* netmsg was embedded in the mbuf, do not reply! */ 432 } 433 434 static void 435 ip_input_handler(struct netmsg *msg0) 436 { 437 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet; 438 439 ip_input(m); 440 /* msg0 was embedded in the mbuf, do not reply! */ 441 } 442 443 /* 444 * IP input routine. Checksum and byte swap header. If fragmented 445 * try to reassemble. Process options. Pass to next level. 446 */ 447 void 448 ip_input(struct mbuf *m) 449 { 450 struct ip *ip; 451 struct in_ifaddr *ia = NULL; 452 struct in_ifaddr_container *iac; 453 int hlen, checkif; 454 u_short sum; 455 struct in_addr pkt_dst; 456 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 457 boolean_t needredispatch = FALSE; 458 struct in_addr odst; /* original dst address(NAT) */ 459 struct m_tag *mtag; 460 struct sockaddr_in *next_hop = NULL; 461 #ifdef FAST_IPSEC 462 struct tdb_ident *tdbi; 463 struct secpolicy *sp; 464 int error; 465 #endif 466 467 M_ASSERTPKTHDR(m); 468 469 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 470 /* Next hop */ 471 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 472 KKASSERT(mtag != NULL); 473 next_hop = m_tag_data(mtag); 474 } 475 476 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 477 /* dummynet already filtered us */ 478 ip = mtod(m, struct ip *); 479 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 480 goto iphack; 481 } 482 483 ipstat.ips_total++; 484 485 /* length checks already done in ip_mport() */ 486 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); 487 ip = mtod(m, struct ip *); 488 489 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 490 ipstat.ips_badvers++; 491 goto bad; 492 } 493 494 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 495 /* length checks already done in ip_mport() */ 496 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 497 KASSERT(m->m_len >= hlen, ("complete IP header not in one mbuf")); 498 499 /* 127/8 must not appear on wire - RFC1122 */ 500 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 501 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 502 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 503 ipstat.ips_badaddr++; 504 goto bad; 505 } 506 } 507 508 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 509 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 510 } else { 511 if (hlen == sizeof(struct ip)) 512 sum = in_cksum_hdr(ip); 513 else 514 sum = in_cksum(m, hlen); 515 } 516 if (sum != 0) { 517 ipstat.ips_badsum++; 518 goto bad; 519 } 520 521 #ifdef ALTQ 522 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 523 /* packet is dropped by traffic conditioner */ 524 return; 525 } 526 #endif 527 /* 528 * Convert fields to host representation. 529 */ 530 ip->ip_len = ntohs(ip->ip_len); 531 ip->ip_off = ntohs(ip->ip_off); 532 533 /* length checks already done in ip_mport() */ 534 KASSERT(ip->ip_len >= hlen, ("total length less then header length")); 535 KASSERT(m->m_pkthdr.len >= ip->ip_len, ("mbuf too short")); 536 537 /* 538 * Trim mbufs if longer than the IP header would have us expect. 539 */ 540 if (m->m_pkthdr.len > ip->ip_len) { 541 if (m->m_len == m->m_pkthdr.len) { 542 m->m_len = ip->ip_len; 543 m->m_pkthdr.len = ip->ip_len; 544 } else { 545 m_adj(m, ip->ip_len - m->m_pkthdr.len); 546 } 547 } 548 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 549 /* 550 * Bypass packet filtering for packets from a tunnel (gif). 551 */ 552 if (ipsec_gethist(m, NULL)) 553 goto pass; 554 #endif 555 556 /* 557 * IpHack's section. 558 * Right now when no processing on packet has done 559 * and it is still fresh out of network we do our black 560 * deals with it. 561 * - Firewall: deny/allow/divert 562 * - Xlate: translate packet's addr/port (NAT). 563 * - Pipe: pass pkt through dummynet. 564 * - Wrap: fake packet's addr/port <unimpl.> 565 * - Encapsulate: put it in another IP and send out. <unimp.> 566 */ 567 568 iphack: 569 /* 570 * If we've been forwarded from the output side, then 571 * skip the firewall a second time 572 */ 573 if (next_hop != NULL) 574 goto ours; 575 576 /* No pfil hooks */ 577 if (!pfil_has_hooks(&inet_pfil_hook)) { 578 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 579 /* 580 * Strip dummynet tags from stranded packets 581 */ 582 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL); 583 KKASSERT(mtag != NULL); 584 m_tag_delete(m, mtag); 585 m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED; 586 } 587 goto pass; 588 } 589 590 /* 591 * Run through list of hooks for input packets. 592 * 593 * NB: Beware of the destination address changing (e.g. 594 * by NAT rewriting). When this happens, tell 595 * ip_forward to do the right thing. 596 */ 597 odst = ip->ip_dst; 598 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN)) 599 return; 600 if (m == NULL) /* consumed by filter */ 601 return; 602 ip = mtod(m, struct ip *); 603 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 604 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 605 606 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 607 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 608 KKASSERT(mtag != NULL); 609 next_hop = m_tag_data(mtag); 610 } 611 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 612 ip_dn_queue(m); 613 return; 614 } 615 if (m->m_pkthdr.fw_flags & FW_MBUF_REDISPATCH) { 616 needredispatch = TRUE; 617 m->m_pkthdr.fw_flags &= ~FW_MBUF_REDISPATCH; 618 } 619 pass: 620 /* 621 * Process options and, if not destined for us, 622 * ship it on. ip_dooptions returns 1 when an 623 * error was detected (causing an icmp message 624 * to be sent and the original packet to be freed). 625 */ 626 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, next_hop)) 627 return; 628 629 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 630 * matter if it is destined to another node, or whether it is 631 * a multicast one, RSVP wants it! and prevents it from being forwarded 632 * anywhere else. Also checks if the rsvp daemon is running before 633 * grabbing the packet. 634 */ 635 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 636 goto ours; 637 638 /* 639 * Check our list of addresses, to see if the packet is for us. 640 * If we don't have any addresses, assume any unicast packet 641 * we receive might be for us (and let the upper layers deal 642 * with it). 643 */ 644 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) && 645 !(m->m_flags & (M_MCAST | M_BCAST))) 646 goto ours; 647 648 /* 649 * Cache the destination address of the packet; this may be 650 * changed by use of 'ipfw fwd'. 651 */ 652 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 653 654 /* 655 * Enable a consistency check between the destination address 656 * and the arrival interface for a unicast packet (the RFC 1122 657 * strong ES model) if IP forwarding is disabled and the packet 658 * is not locally generated and the packet is not subject to 659 * 'ipfw fwd'. 660 * 661 * XXX - Checking also should be disabled if the destination 662 * address is ipnat'ed to a different interface. 663 * 664 * XXX - Checking is incompatible with IP aliases added 665 * to the loopback interface instead of the interface where 666 * the packets are received. 667 */ 668 checkif = ip_checkinterface && 669 !ipforwarding && 670 m->m_pkthdr.rcvif != NULL && 671 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 672 next_hop == NULL; 673 674 /* 675 * Check for exact addresses in the hash bucket. 676 */ 677 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 678 ia = iac->ia; 679 680 /* 681 * If the address matches, verify that the packet 682 * arrived via the correct interface if checking is 683 * enabled. 684 */ 685 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 686 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 687 goto ours; 688 } 689 ia = NULL; 690 691 /* 692 * Check for broadcast addresses. 693 * 694 * Only accept broadcast packets that arrive via the matching 695 * interface. Reception of forwarded directed broadcasts would 696 * be handled via ip_forward() and ether_output() with the loopback 697 * into the stack for SIMPLEX interfaces handled by ether_output(). 698 */ 699 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 700 struct ifaddr_container *ifac; 701 702 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 703 ifa_link) { 704 struct ifaddr *ifa = ifac->ifa; 705 706 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 707 continue; 708 if (ifa->ifa_addr->sa_family != AF_INET) 709 continue; 710 ia = ifatoia(ifa); 711 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 712 pkt_dst.s_addr) 713 goto ours; 714 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 715 goto ours; 716 #ifdef BOOTP_COMPAT 717 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 718 goto ours; 719 #endif 720 } 721 } 722 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 723 struct in_multi *inm; 724 725 /* XXX Multicast is not MPSAFE yet */ 726 get_mplock(); 727 728 if (ip_mrouter != NULL) { 729 /* 730 * If we are acting as a multicast router, all 731 * incoming multicast packets are passed to the 732 * kernel-level multicast forwarding function. 733 * The packet is returned (relatively) intact; if 734 * ip_mforward() returns a non-zero value, the packet 735 * must be discarded, else it may be accepted below. 736 */ 737 if (ip_mforward != NULL && 738 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 739 rel_mplock(); 740 ipstat.ips_cantforward++; 741 m_freem(m); 742 return; 743 } 744 745 /* 746 * The process-level routing daemon needs to receive 747 * all multicast IGMP packets, whether or not this 748 * host belongs to their destination groups. 749 */ 750 if (ip->ip_p == IPPROTO_IGMP) { 751 rel_mplock(); 752 goto ours; 753 } 754 ipstat.ips_forward++; 755 } 756 /* 757 * See if we belong to the destination multicast group on the 758 * arrival interface. 759 */ 760 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 761 if (inm == NULL) { 762 rel_mplock(); 763 ipstat.ips_notmember++; 764 m_freem(m); 765 return; 766 } 767 768 rel_mplock(); 769 goto ours; 770 } 771 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 772 goto ours; 773 if (ip->ip_dst.s_addr == INADDR_ANY) 774 goto ours; 775 776 /* 777 * FAITH(Firewall Aided Internet Translator) 778 */ 779 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 780 if (ip_keepfaith) { 781 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 782 goto ours; 783 } 784 m_freem(m); 785 return; 786 } 787 788 /* 789 * Not for us; forward if possible and desirable. 790 */ 791 if (!ipforwarding) { 792 ipstat.ips_cantforward++; 793 m_freem(m); 794 } else { 795 #ifdef IPSEC 796 /* 797 * Enforce inbound IPsec SPD. 798 */ 799 if (ipsec4_in_reject(m, NULL)) { 800 ipsecstat.in_polvio++; 801 goto bad; 802 } 803 #endif 804 #ifdef FAST_IPSEC 805 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 806 crit_enter(); 807 if (mtag != NULL) { 808 tdbi = (struct tdb_ident *)m_tag_data(mtag); 809 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 810 } else { 811 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 812 IP_FORWARDING, &error); 813 } 814 if (sp == NULL) { /* NB: can happen if error */ 815 crit_exit(); 816 /*XXX error stat???*/ 817 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 818 goto bad; 819 } 820 821 /* 822 * Check security policy against packet attributes. 823 */ 824 error = ipsec_in_reject(sp, m); 825 KEY_FREESP(&sp); 826 crit_exit(); 827 if (error) { 828 ipstat.ips_cantforward++; 829 goto bad; 830 } 831 #endif 832 ip_forward(m, using_srcrt, next_hop); 833 } 834 return; 835 836 ours: 837 838 /* 839 * IPSTEALTH: Process non-routing options only 840 * if the packet is destined for us. 841 */ 842 if (ipstealth && 843 hlen > sizeof(struct ip) && 844 ip_dooptions(m, 1, next_hop)) 845 return; 846 847 /* Count the packet in the ip address stats */ 848 if (ia != NULL) { 849 ia->ia_ifa.if_ipackets++; 850 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 851 } 852 853 /* 854 * If offset or IP_MF are set, must reassemble. 855 * Otherwise, nothing need be done. 856 * (We could look in the reassembly queue to see 857 * if the packet was previously fragmented, 858 * but it's not worth the time; just let them time out.) 859 */ 860 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 861 /* 862 * Attempt reassembly; if it succeeds, proceed. 863 * ip_reass() will return a different mbuf. 864 */ 865 m = ip_reass(m); 866 if (m == NULL) 867 return; 868 ip = mtod(m, struct ip *); 869 870 /* Get the header length of the reassembled packet */ 871 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 872 873 needredispatch = TRUE; 874 } else { 875 ip->ip_len -= hlen; 876 } 877 878 #ifdef IPSEC 879 /* 880 * enforce IPsec policy checking if we are seeing last header. 881 * note that we do not visit this with protocols with pcb layer 882 * code - like udp/tcp/raw ip. 883 */ 884 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 885 ipsec4_in_reject(m, NULL)) { 886 ipsecstat.in_polvio++; 887 goto bad; 888 } 889 #endif 890 #if FAST_IPSEC 891 /* 892 * enforce IPsec policy checking if we are seeing last header. 893 * note that we do not visit this with protocols with pcb layer 894 * code - like udp/tcp/raw ip. 895 */ 896 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 897 /* 898 * Check if the packet has already had IPsec processing 899 * done. If so, then just pass it along. This tag gets 900 * set during AH, ESP, etc. input handling, before the 901 * packet is returned to the ip input queue for delivery. 902 */ 903 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 904 crit_enter(); 905 if (mtag != NULL) { 906 tdbi = (struct tdb_ident *)m_tag_data(mtag); 907 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 908 } else { 909 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 910 IP_FORWARDING, &error); 911 } 912 if (sp != NULL) { 913 /* 914 * Check security policy against packet attributes. 915 */ 916 error = ipsec_in_reject(sp, m); 917 KEY_FREESP(&sp); 918 } else { 919 /* XXX error stat??? */ 920 error = EINVAL; 921 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 922 goto bad; 923 } 924 crit_exit(); 925 if (error) 926 goto bad; 927 } 928 #endif /* FAST_IPSEC */ 929 930 ipstat.ips_delivered++; 931 if (needredispatch) { 932 struct netmsg_packet *pmsg; 933 lwkt_port_t port; 934 935 ip->ip_off = htons(ip->ip_off); 936 ip->ip_len = htons(ip->ip_len); 937 port = ip_mport_in(&m); 938 if (port == NULL) 939 return; 940 941 pmsg = &m->m_hdr.mh_netmsg; 942 netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, MSGF_MPSAFE, 943 transport_processing_handler); 944 pmsg->nm_packet = m; 945 pmsg->nm_netmsg.nm_lmsg.u.ms_result = hlen; 946 947 ip = mtod(m, struct ip *); 948 ip->ip_len = ntohs(ip->ip_len); 949 ip->ip_off = ntohs(ip->ip_off); 950 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg); 951 } else { 952 transport_processing_oncpu(m, hlen, ip); 953 } 954 return; 955 956 bad: 957 m_freem(m); 958 } 959 960 /* 961 * Take incoming datagram fragment and try to reassemble it into 962 * whole datagram. If a chain for reassembly of this datagram already 963 * exists, then it is given as fp; otherwise have to make a chain. 964 */ 965 struct mbuf * 966 ip_reass(struct mbuf *m) 967 { 968 struct ip *ip = mtod(m, struct ip *); 969 struct mbuf *p = NULL, *q, *nq; 970 struct mbuf *n; 971 struct ipq *fp = NULL; 972 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 973 int i, next; 974 u_short sum; 975 976 /* If maxnipq is 0, never accept fragments. */ 977 if (maxnipq == 0) { 978 ipstat.ips_fragments++; 979 ipstat.ips_fragdropped++; 980 m_freem(m); 981 return NULL; 982 } 983 984 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 985 /* 986 * Look for queue of fragments of this datagram. 987 */ 988 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 989 if (ip->ip_id == fp->ipq_id && 990 ip->ip_src.s_addr == fp->ipq_src.s_addr && 991 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 992 ip->ip_p == fp->ipq_p) 993 goto found; 994 995 fp = NULL; 996 997 /* 998 * Enforce upper bound on number of fragmented packets 999 * for which we attempt reassembly; 1000 * If maxnipq is -1, accept all fragments without limitation. 1001 */ 1002 if (nipq > maxnipq && maxnipq > 0) { 1003 /* 1004 * drop something from the tail of the current queue 1005 * before proceeding further 1006 */ 1007 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 1008 for (i = 0; i < IPREASS_NHASH; i++) { 1009 if (ipq[i].prev != &ipq[i]) { 1010 ipstat.ips_fragtimeout += 1011 ipq[i].prev->ipq_nfrags; 1012 ip_freef(ipq[i].prev); 1013 break; 1014 } 1015 } 1016 } else { 1017 ipstat.ips_fragtimeout += 1018 ipq[sum].prev->ipq_nfrags; 1019 ip_freef(ipq[sum].prev); 1020 } 1021 } 1022 found: 1023 /* 1024 * Adjust ip_len to not reflect header, 1025 * convert offset of this to bytes. 1026 */ 1027 ip->ip_len -= hlen; 1028 if (ip->ip_off & IP_MF) { 1029 /* 1030 * Make sure that fragments have a data length 1031 * that's a non-zero multiple of 8 bytes. 1032 */ 1033 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 1034 ipstat.ips_toosmall++; /* XXX */ 1035 m_freem(m); 1036 return NULL; 1037 } 1038 m->m_flags |= M_FRAG; 1039 } else 1040 m->m_flags &= ~M_FRAG; 1041 ip->ip_off <<= 3; 1042 1043 ipstat.ips_fragments++; 1044 m->m_pkthdr.header = ip; 1045 1046 /* 1047 * If the hardware has not done csum over this fragment 1048 * then csum_data is not valid at all. 1049 */ 1050 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) 1051 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) { 1052 m->m_pkthdr.csum_data = 0; 1053 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR); 1054 } 1055 1056 /* 1057 * Presence of header sizes in mbufs 1058 * would confuse code below. 1059 */ 1060 m->m_data += hlen; 1061 m->m_len -= hlen; 1062 1063 /* 1064 * If first fragment to arrive, create a reassembly queue. 1065 */ 1066 if (fp == NULL) { 1067 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1068 goto dropfrag; 1069 insque(fp, &ipq[sum]); 1070 nipq++; 1071 fp->ipq_nfrags = 1; 1072 fp->ipq_ttl = IPFRAGTTL; 1073 fp->ipq_p = ip->ip_p; 1074 fp->ipq_id = ip->ip_id; 1075 fp->ipq_src = ip->ip_src; 1076 fp->ipq_dst = ip->ip_dst; 1077 fp->ipq_frags = m; 1078 m->m_nextpkt = NULL; 1079 goto inserted; 1080 } else { 1081 fp->ipq_nfrags++; 1082 } 1083 1084 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1085 1086 /* 1087 * Find a segment which begins after this one does. 1088 */ 1089 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1090 if (GETIP(q)->ip_off > ip->ip_off) 1091 break; 1092 1093 /* 1094 * If there is a preceding segment, it may provide some of 1095 * our data already. If so, drop the data from the incoming 1096 * segment. If it provides all of our data, drop us, otherwise 1097 * stick new segment in the proper place. 1098 * 1099 * If some of the data is dropped from the the preceding 1100 * segment, then it's checksum is invalidated. 1101 */ 1102 if (p) { 1103 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1104 if (i > 0) { 1105 if (i >= ip->ip_len) 1106 goto dropfrag; 1107 m_adj(m, i); 1108 m->m_pkthdr.csum_flags = 0; 1109 ip->ip_off += i; 1110 ip->ip_len -= i; 1111 } 1112 m->m_nextpkt = p->m_nextpkt; 1113 p->m_nextpkt = m; 1114 } else { 1115 m->m_nextpkt = fp->ipq_frags; 1116 fp->ipq_frags = m; 1117 } 1118 1119 /* 1120 * While we overlap succeeding segments trim them or, 1121 * if they are completely covered, dequeue them. 1122 */ 1123 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1124 q = nq) { 1125 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1126 if (i < GETIP(q)->ip_len) { 1127 GETIP(q)->ip_len -= i; 1128 GETIP(q)->ip_off += i; 1129 m_adj(q, i); 1130 q->m_pkthdr.csum_flags = 0; 1131 break; 1132 } 1133 nq = q->m_nextpkt; 1134 m->m_nextpkt = nq; 1135 ipstat.ips_fragdropped++; 1136 fp->ipq_nfrags--; 1137 q->m_nextpkt = NULL; 1138 m_freem(q); 1139 } 1140 1141 inserted: 1142 /* 1143 * Check for complete reassembly and perform frag per packet 1144 * limiting. 1145 * 1146 * Frag limiting is performed here so that the nth frag has 1147 * a chance to complete the packet before we drop the packet. 1148 * As a result, n+1 frags are actually allowed per packet, but 1149 * only n will ever be stored. (n = maxfragsperpacket.) 1150 * 1151 */ 1152 next = 0; 1153 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1154 if (GETIP(q)->ip_off != next) { 1155 if (fp->ipq_nfrags > maxfragsperpacket) { 1156 ipstat.ips_fragdropped += fp->ipq_nfrags; 1157 ip_freef(fp); 1158 } 1159 return (NULL); 1160 } 1161 next += GETIP(q)->ip_len; 1162 } 1163 /* Make sure the last packet didn't have the IP_MF flag */ 1164 if (p->m_flags & M_FRAG) { 1165 if (fp->ipq_nfrags > maxfragsperpacket) { 1166 ipstat.ips_fragdropped += fp->ipq_nfrags; 1167 ip_freef(fp); 1168 } 1169 return (NULL); 1170 } 1171 1172 /* 1173 * Reassembly is complete. Make sure the packet is a sane size. 1174 */ 1175 q = fp->ipq_frags; 1176 ip = GETIP(q); 1177 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1178 ipstat.ips_toolong++; 1179 ipstat.ips_fragdropped += fp->ipq_nfrags; 1180 ip_freef(fp); 1181 return (NULL); 1182 } 1183 1184 /* 1185 * Concatenate fragments. 1186 */ 1187 m = q; 1188 n = m->m_next; 1189 m->m_next = NULL; 1190 m_cat(m, n); 1191 nq = q->m_nextpkt; 1192 q->m_nextpkt = NULL; 1193 for (q = nq; q != NULL; q = nq) { 1194 nq = q->m_nextpkt; 1195 q->m_nextpkt = NULL; 1196 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1197 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1198 m_cat(m, q); 1199 } 1200 1201 /* 1202 * Clean up the 1's complement checksum. Carry over 16 bits must 1203 * be added back. This assumes no more then 65535 packet fragments 1204 * were reassembled. A second carry can also occur (but not a third). 1205 */ 1206 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + 1207 (m->m_pkthdr.csum_data >> 16); 1208 if (m->m_pkthdr.csum_data > 0xFFFF) 1209 m->m_pkthdr.csum_data -= 0xFFFF; 1210 1211 /* 1212 * Create header for new ip packet by 1213 * modifying header of first packet; 1214 * dequeue and discard fragment reassembly header. 1215 * Make header visible. 1216 */ 1217 ip->ip_len = next; 1218 ip->ip_src = fp->ipq_src; 1219 ip->ip_dst = fp->ipq_dst; 1220 remque(fp); 1221 nipq--; 1222 mpipe_free(&ipq_mpipe, fp); 1223 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1224 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1225 /* some debugging cruft by sklower, below, will go away soon */ 1226 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1227 int plen = 0; 1228 1229 for (n = m; n; n = n->m_next) 1230 plen += n->m_len; 1231 m->m_pkthdr.len = plen; 1232 } 1233 1234 ipstat.ips_reassembled++; 1235 return (m); 1236 1237 dropfrag: 1238 ipstat.ips_fragdropped++; 1239 if (fp != NULL) 1240 fp->ipq_nfrags--; 1241 m_freem(m); 1242 return (NULL); 1243 1244 #undef GETIP 1245 } 1246 1247 /* 1248 * Free a fragment reassembly header and all 1249 * associated datagrams. 1250 */ 1251 static void 1252 ip_freef(struct ipq *fp) 1253 { 1254 struct mbuf *q; 1255 1256 while (fp->ipq_frags) { 1257 q = fp->ipq_frags; 1258 fp->ipq_frags = q->m_nextpkt; 1259 q->m_nextpkt = NULL; 1260 m_freem(q); 1261 } 1262 remque(fp); 1263 mpipe_free(&ipq_mpipe, fp); 1264 nipq--; 1265 } 1266 1267 /* 1268 * IP timer processing; 1269 * if a timer expires on a reassembly 1270 * queue, discard it. 1271 */ 1272 void 1273 ip_slowtimo(void) 1274 { 1275 struct ipq *fp; 1276 int i; 1277 1278 crit_enter(); 1279 for (i = 0; i < IPREASS_NHASH; i++) { 1280 fp = ipq[i].next; 1281 if (fp == NULL) 1282 continue; 1283 while (fp != &ipq[i]) { 1284 --fp->ipq_ttl; 1285 fp = fp->next; 1286 if (fp->prev->ipq_ttl == 0) { 1287 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1288 ip_freef(fp->prev); 1289 } 1290 } 1291 } 1292 /* 1293 * If we are over the maximum number of fragments 1294 * (due to the limit being lowered), drain off 1295 * enough to get down to the new limit. 1296 */ 1297 if (maxnipq >= 0 && nipq > maxnipq) { 1298 for (i = 0; i < IPREASS_NHASH; i++) { 1299 while (nipq > maxnipq && 1300 (ipq[i].next != &ipq[i])) { 1301 ipstat.ips_fragdropped += 1302 ipq[i].next->ipq_nfrags; 1303 ip_freef(ipq[i].next); 1304 } 1305 } 1306 } 1307 ipflow_slowtimo(); 1308 crit_exit(); 1309 } 1310 1311 /* 1312 * Drain off all datagram fragments. 1313 */ 1314 void 1315 ip_drain(void) 1316 { 1317 int i; 1318 1319 for (i = 0; i < IPREASS_NHASH; i++) { 1320 while (ipq[i].next != &ipq[i]) { 1321 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1322 ip_freef(ipq[i].next); 1323 } 1324 } 1325 in_rtqdrain(); 1326 } 1327 1328 /* 1329 * Do option processing on a datagram, 1330 * possibly discarding it if bad options are encountered, 1331 * or forwarding it if source-routed. 1332 * The pass argument is used when operating in the IPSTEALTH 1333 * mode to tell what options to process: 1334 * [LS]SRR (pass 0) or the others (pass 1). 1335 * The reason for as many as two passes is that when doing IPSTEALTH, 1336 * non-routing options should be processed only if the packet is for us. 1337 * Returns 1 if packet has been forwarded/freed, 1338 * 0 if the packet should be processed further. 1339 */ 1340 static int 1341 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1342 { 1343 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1344 struct ip *ip = mtod(m, struct ip *); 1345 u_char *cp; 1346 struct in_ifaddr *ia; 1347 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1348 boolean_t forward = FALSE; 1349 struct in_addr *sin, dst; 1350 n_time ntime; 1351 1352 dst = ip->ip_dst; 1353 cp = (u_char *)(ip + 1); 1354 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1355 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1356 opt = cp[IPOPT_OPTVAL]; 1357 if (opt == IPOPT_EOL) 1358 break; 1359 if (opt == IPOPT_NOP) 1360 optlen = 1; 1361 else { 1362 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1363 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1364 goto bad; 1365 } 1366 optlen = cp[IPOPT_OLEN]; 1367 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1368 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1369 goto bad; 1370 } 1371 } 1372 switch (opt) { 1373 1374 default: 1375 break; 1376 1377 /* 1378 * Source routing with record. 1379 * Find interface with current destination address. 1380 * If none on this machine then drop if strictly routed, 1381 * or do nothing if loosely routed. 1382 * Record interface address and bring up next address 1383 * component. If strictly routed make sure next 1384 * address is on directly accessible net. 1385 */ 1386 case IPOPT_LSRR: 1387 case IPOPT_SSRR: 1388 if (ipstealth && pass > 0) 1389 break; 1390 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1391 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1392 goto bad; 1393 } 1394 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1395 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1396 goto bad; 1397 } 1398 ipaddr.sin_addr = ip->ip_dst; 1399 ia = (struct in_ifaddr *) 1400 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1401 if (ia == NULL) { 1402 if (opt == IPOPT_SSRR) { 1403 type = ICMP_UNREACH; 1404 code = ICMP_UNREACH_SRCFAIL; 1405 goto bad; 1406 } 1407 if (!ip_dosourceroute) 1408 goto nosourcerouting; 1409 /* 1410 * Loose routing, and not at next destination 1411 * yet; nothing to do except forward. 1412 */ 1413 break; 1414 } 1415 off--; /* 0 origin */ 1416 if (off > optlen - (int)sizeof(struct in_addr)) { 1417 /* 1418 * End of source route. Should be for us. 1419 */ 1420 if (!ip_acceptsourceroute) 1421 goto nosourcerouting; 1422 save_rte(m, cp, ip->ip_src); 1423 break; 1424 } 1425 if (ipstealth) 1426 goto dropit; 1427 if (!ip_dosourceroute) { 1428 if (ipforwarding) { 1429 char buf[sizeof "aaa.bbb.ccc.ddd"]; 1430 1431 /* 1432 * Acting as a router, so generate ICMP 1433 */ 1434 nosourcerouting: 1435 strcpy(buf, inet_ntoa(ip->ip_dst)); 1436 log(LOG_WARNING, 1437 "attempted source route from %s to %s\n", 1438 inet_ntoa(ip->ip_src), buf); 1439 type = ICMP_UNREACH; 1440 code = ICMP_UNREACH_SRCFAIL; 1441 goto bad; 1442 } else { 1443 /* 1444 * Not acting as a router, 1445 * so silently drop. 1446 */ 1447 dropit: 1448 ipstat.ips_cantforward++; 1449 m_freem(m); 1450 return (1); 1451 } 1452 } 1453 1454 /* 1455 * locate outgoing interface 1456 */ 1457 memcpy(&ipaddr.sin_addr, cp + off, 1458 sizeof ipaddr.sin_addr); 1459 1460 if (opt == IPOPT_SSRR) { 1461 #define INA struct in_ifaddr * 1462 #define SA struct sockaddr * 1463 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1464 == NULL) 1465 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1466 } else 1467 ia = ip_rtaddr(ipaddr.sin_addr, 1468 &ipforward_rt[mycpuid]); 1469 if (ia == NULL) { 1470 type = ICMP_UNREACH; 1471 code = ICMP_UNREACH_SRCFAIL; 1472 goto bad; 1473 } 1474 ip->ip_dst = ipaddr.sin_addr; 1475 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1476 sizeof(struct in_addr)); 1477 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1478 /* 1479 * Let ip_intr's mcast routing check handle mcast pkts 1480 */ 1481 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1482 break; 1483 1484 case IPOPT_RR: 1485 if (ipstealth && pass == 0) 1486 break; 1487 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1488 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1489 goto bad; 1490 } 1491 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1492 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1493 goto bad; 1494 } 1495 /* 1496 * If no space remains, ignore. 1497 */ 1498 off--; /* 0 origin */ 1499 if (off > optlen - (int)sizeof(struct in_addr)) 1500 break; 1501 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1502 sizeof ipaddr.sin_addr); 1503 /* 1504 * locate outgoing interface; if we're the destination, 1505 * use the incoming interface (should be same). 1506 */ 1507 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1508 (ia = ip_rtaddr(ipaddr.sin_addr, 1509 &ipforward_rt[mycpuid])) 1510 == NULL) { 1511 type = ICMP_UNREACH; 1512 code = ICMP_UNREACH_HOST; 1513 goto bad; 1514 } 1515 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1516 sizeof(struct in_addr)); 1517 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1518 break; 1519 1520 case IPOPT_TS: 1521 if (ipstealth && pass == 0) 1522 break; 1523 code = cp - (u_char *)ip; 1524 if (optlen < 4 || optlen > 40) { 1525 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1526 goto bad; 1527 } 1528 if ((off = cp[IPOPT_OFFSET]) < 5) { 1529 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1530 goto bad; 1531 } 1532 if (off > optlen - (int)sizeof(int32_t)) { 1533 cp[IPOPT_OFFSET + 1] += (1 << 4); 1534 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1535 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1536 goto bad; 1537 } 1538 break; 1539 } 1540 off--; /* 0 origin */ 1541 sin = (struct in_addr *)(cp + off); 1542 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1543 1544 case IPOPT_TS_TSONLY: 1545 break; 1546 1547 case IPOPT_TS_TSANDADDR: 1548 if (off + sizeof(n_time) + 1549 sizeof(struct in_addr) > optlen) { 1550 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1551 goto bad; 1552 } 1553 ipaddr.sin_addr = dst; 1554 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1555 m->m_pkthdr.rcvif); 1556 if (ia == NULL) 1557 continue; 1558 memcpy(sin, &IA_SIN(ia)->sin_addr, 1559 sizeof(struct in_addr)); 1560 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1561 off += sizeof(struct in_addr); 1562 break; 1563 1564 case IPOPT_TS_PRESPEC: 1565 if (off + sizeof(n_time) + 1566 sizeof(struct in_addr) > optlen) { 1567 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1568 goto bad; 1569 } 1570 memcpy(&ipaddr.sin_addr, sin, 1571 sizeof(struct in_addr)); 1572 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1573 continue; 1574 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1575 off += sizeof(struct in_addr); 1576 break; 1577 1578 default: 1579 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1580 goto bad; 1581 } 1582 ntime = iptime(); 1583 memcpy(cp + off, &ntime, sizeof(n_time)); 1584 cp[IPOPT_OFFSET] += sizeof(n_time); 1585 } 1586 } 1587 if (forward && ipforwarding) { 1588 ip_forward(m, TRUE, next_hop); 1589 return (1); 1590 } 1591 return (0); 1592 bad: 1593 icmp_error(m, type, code, 0, 0); 1594 ipstat.ips_badoptions++; 1595 return (1); 1596 } 1597 1598 /* 1599 * Given address of next destination (final or next hop), 1600 * return internet address info of interface to be used to get there. 1601 */ 1602 struct in_ifaddr * 1603 ip_rtaddr(struct in_addr dst, struct route *ro) 1604 { 1605 struct sockaddr_in *sin; 1606 1607 sin = (struct sockaddr_in *)&ro->ro_dst; 1608 1609 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1610 if (ro->ro_rt != NULL) { 1611 RTFREE(ro->ro_rt); 1612 ro->ro_rt = NULL; 1613 } 1614 sin->sin_family = AF_INET; 1615 sin->sin_len = sizeof *sin; 1616 sin->sin_addr = dst; 1617 rtalloc_ign(ro, RTF_PRCLONING); 1618 } 1619 1620 if (ro->ro_rt == NULL) 1621 return (NULL); 1622 1623 return (ifatoia(ro->ro_rt->rt_ifa)); 1624 } 1625 1626 /* 1627 * Save incoming source route for use in replies, 1628 * to be picked up later by ip_srcroute if the receiver is interested. 1629 */ 1630 static void 1631 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1632 { 1633 struct m_tag *mtag; 1634 struct ip_srcrt_opt *opt; 1635 unsigned olen; 1636 1637 mtag = m_tag_get(PACKET_TAG_IPSRCRT, sizeof(*opt), MB_DONTWAIT); 1638 if (mtag == NULL) 1639 return; 1640 opt = m_tag_data(mtag); 1641 1642 olen = option[IPOPT_OLEN]; 1643 #ifdef DIAGNOSTIC 1644 if (ipprintfs) 1645 kprintf("save_rte: olen %d\n", olen); 1646 #endif 1647 if (olen > sizeof(opt->ip_srcrt) - (1 + sizeof(dst))) { 1648 m_tag_free(mtag); 1649 return; 1650 } 1651 bcopy(option, opt->ip_srcrt.srcopt, olen); 1652 opt->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1653 opt->ip_srcrt.dst = dst; 1654 m_tag_prepend(m, mtag); 1655 } 1656 1657 /* 1658 * Retrieve incoming source route for use in replies, 1659 * in the same form used by setsockopt. 1660 * The first hop is placed before the options, will be removed later. 1661 */ 1662 struct mbuf * 1663 ip_srcroute(struct mbuf *m0) 1664 { 1665 struct in_addr *p, *q; 1666 struct mbuf *m; 1667 struct m_tag *mtag; 1668 struct ip_srcrt_opt *opt; 1669 1670 if (m0 == NULL) 1671 return NULL; 1672 1673 mtag = m_tag_find(m0, PACKET_TAG_IPSRCRT, NULL); 1674 if (mtag == NULL) 1675 return NULL; 1676 opt = m_tag_data(mtag); 1677 1678 if (opt->ip_nhops == 0) 1679 return (NULL); 1680 m = m_get(MB_DONTWAIT, MT_HEADER); 1681 if (m == NULL) 1682 return (NULL); 1683 1684 #define OPTSIZ (sizeof(opt->ip_srcrt.nop) + sizeof(opt->ip_srcrt.srcopt)) 1685 1686 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1687 m->m_len = opt->ip_nhops * sizeof(struct in_addr) + 1688 sizeof(struct in_addr) + OPTSIZ; 1689 #ifdef DIAGNOSTIC 1690 if (ipprintfs) { 1691 kprintf("ip_srcroute: nhops %d mlen %d", 1692 opt->ip_nhops, m->m_len); 1693 } 1694 #endif 1695 1696 /* 1697 * First save first hop for return route 1698 */ 1699 p = &opt->ip_srcrt.route[opt->ip_nhops - 1]; 1700 *(mtod(m, struct in_addr *)) = *p--; 1701 #ifdef DIAGNOSTIC 1702 if (ipprintfs) 1703 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1704 #endif 1705 1706 /* 1707 * Copy option fields and padding (nop) to mbuf. 1708 */ 1709 opt->ip_srcrt.nop = IPOPT_NOP; 1710 opt->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1711 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &opt->ip_srcrt.nop, 1712 OPTSIZ); 1713 q = (struct in_addr *)(mtod(m, caddr_t) + 1714 sizeof(struct in_addr) + OPTSIZ); 1715 #undef OPTSIZ 1716 /* 1717 * Record return path as an IP source route, 1718 * reversing the path (pointers are now aligned). 1719 */ 1720 while (p >= opt->ip_srcrt.route) { 1721 #ifdef DIAGNOSTIC 1722 if (ipprintfs) 1723 kprintf(" %x", ntohl(q->s_addr)); 1724 #endif 1725 *q++ = *p--; 1726 } 1727 /* 1728 * Last hop goes to final destination. 1729 */ 1730 *q = opt->ip_srcrt.dst; 1731 m_tag_delete(m0, mtag); 1732 #ifdef DIAGNOSTIC 1733 if (ipprintfs) 1734 kprintf(" %x\n", ntohl(q->s_addr)); 1735 #endif 1736 return (m); 1737 } 1738 1739 /* 1740 * Strip out IP options. 1741 */ 1742 void 1743 ip_stripoptions(struct mbuf *m) 1744 { 1745 int datalen; 1746 struct ip *ip = mtod(m, struct ip *); 1747 caddr_t opts; 1748 int optlen; 1749 1750 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1751 opts = (caddr_t)(ip + 1); 1752 datalen = m->m_len - (sizeof(struct ip) + optlen); 1753 bcopy(opts + optlen, opts, datalen); 1754 m->m_len -= optlen; 1755 if (m->m_flags & M_PKTHDR) 1756 m->m_pkthdr.len -= optlen; 1757 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1758 } 1759 1760 u_char inetctlerrmap[PRC_NCMDS] = { 1761 0, 0, 0, 0, 1762 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1763 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1764 EMSGSIZE, EHOSTUNREACH, 0, 0, 1765 0, 0, 0, 0, 1766 ENOPROTOOPT, ECONNREFUSED 1767 }; 1768 1769 /* 1770 * Forward a packet. If some error occurs return the sender 1771 * an icmp packet. Note we can't always generate a meaningful 1772 * icmp message because icmp doesn't have a large enough repertoire 1773 * of codes and types. 1774 * 1775 * If not forwarding, just drop the packet. This could be confusing 1776 * if ipforwarding was zero but some routing protocol was advancing 1777 * us as a gateway to somewhere. However, we must let the routing 1778 * protocol deal with that. 1779 * 1780 * The using_srcrt parameter indicates whether the packet is being forwarded 1781 * via a source route. 1782 */ 1783 void 1784 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop) 1785 { 1786 struct ip *ip = mtod(m, struct ip *); 1787 struct sockaddr_in *ipforward_rtaddr; 1788 struct rtentry *rt; 1789 int error, type = 0, code = 0, destmtu = 0; 1790 struct mbuf *mcopy; 1791 n_long dest; 1792 struct in_addr pkt_dst; 1793 struct route *cache_rt = &ipforward_rt[mycpuid]; 1794 1795 dest = INADDR_ANY; 1796 /* 1797 * Cache the destination address of the packet; this may be 1798 * changed by use of 'ipfw fwd'. 1799 */ 1800 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 1801 1802 #ifdef DIAGNOSTIC 1803 if (ipprintfs) 1804 kprintf("forward: src %x dst %x ttl %x\n", 1805 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1806 #endif 1807 1808 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1809 ipstat.ips_cantforward++; 1810 m_freem(m); 1811 return; 1812 } 1813 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1814 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1815 return; 1816 } 1817 1818 ipforward_rtaddr = (struct sockaddr_in *) &cache_rt->ro_dst; 1819 if (cache_rt->ro_rt == NULL || 1820 ipforward_rtaddr->sin_addr.s_addr != pkt_dst.s_addr) { 1821 if (cache_rt->ro_rt != NULL) { 1822 RTFREE(cache_rt->ro_rt); 1823 cache_rt->ro_rt = NULL; 1824 } 1825 ipforward_rtaddr->sin_family = AF_INET; 1826 ipforward_rtaddr->sin_len = sizeof(struct sockaddr_in); 1827 ipforward_rtaddr->sin_addr = pkt_dst; 1828 rtalloc_ign(cache_rt, RTF_PRCLONING); 1829 if (cache_rt->ro_rt == NULL) { 1830 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1831 return; 1832 } 1833 } 1834 rt = cache_rt->ro_rt; 1835 1836 /* 1837 * Save the IP header and at most 8 bytes of the payload, 1838 * in case we need to generate an ICMP message to the src. 1839 * 1840 * XXX this can be optimized a lot by saving the data in a local 1841 * buffer on the stack (72 bytes at most), and only allocating the 1842 * mbuf if really necessary. The vast majority of the packets 1843 * are forwarded without having to send an ICMP back (either 1844 * because unnecessary, or because rate limited), so we are 1845 * really we are wasting a lot of work here. 1846 * 1847 * We don't use m_copy() because it might return a reference 1848 * to a shared cluster. Both this function and ip_output() 1849 * assume exclusive access to the IP header in `m', so any 1850 * data in a cluster may change before we reach icmp_error(). 1851 */ 1852 MGETHDR(mcopy, MB_DONTWAIT, m->m_type); 1853 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) { 1854 /* 1855 * It's probably ok if the pkthdr dup fails (because 1856 * the deep copy of the tag chain failed), but for now 1857 * be conservative and just discard the copy since 1858 * code below may some day want the tags. 1859 */ 1860 m_free(mcopy); 1861 mcopy = NULL; 1862 } 1863 if (mcopy != NULL) { 1864 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1865 (int)ip->ip_len); 1866 mcopy->m_pkthdr.len = mcopy->m_len; 1867 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1868 } 1869 1870 if (!ipstealth) 1871 ip->ip_ttl -= IPTTLDEC; 1872 1873 /* 1874 * If forwarding packet using same interface that it came in on, 1875 * perhaps should send a redirect to sender to shortcut a hop. 1876 * Only send redirect if source is sending directly to us, 1877 * and if packet was not source routed (or has any options). 1878 * Also, don't send redirect if forwarding using a default route 1879 * or a route modified by a redirect. 1880 */ 1881 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1882 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1883 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1884 ipsendredirects && !using_srcrt && next_hop == NULL) { 1885 u_long src = ntohl(ip->ip_src.s_addr); 1886 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa; 1887 1888 if (rt_ifa != NULL && 1889 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) { 1890 if (rt->rt_flags & RTF_GATEWAY) 1891 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1892 else 1893 dest = pkt_dst.s_addr; 1894 /* 1895 * Router requirements says to only send 1896 * host redirects. 1897 */ 1898 type = ICMP_REDIRECT; 1899 code = ICMP_REDIRECT_HOST; 1900 #ifdef DIAGNOSTIC 1901 if (ipprintfs) 1902 kprintf("redirect (%d) to %x\n", code, dest); 1903 #endif 1904 } 1905 } 1906 1907 error = ip_output(m, NULL, cache_rt, IP_FORWARDING, NULL, NULL); 1908 if (error == 0) { 1909 ipstat.ips_forward++; 1910 if (type == 0) { 1911 if (mcopy) { 1912 ipflow_create(cache_rt, mcopy); 1913 m_freem(mcopy); 1914 } 1915 return; /* most common case */ 1916 } else { 1917 ipstat.ips_redirectsent++; 1918 } 1919 } else { 1920 ipstat.ips_cantforward++; 1921 } 1922 1923 if (mcopy == NULL) 1924 return; 1925 1926 /* 1927 * Send ICMP message. 1928 */ 1929 1930 switch (error) { 1931 1932 case 0: /* forwarded, but need redirect */ 1933 /* type, code set above */ 1934 break; 1935 1936 case ENETUNREACH: /* shouldn't happen, checked above */ 1937 case EHOSTUNREACH: 1938 case ENETDOWN: 1939 case EHOSTDOWN: 1940 default: 1941 type = ICMP_UNREACH; 1942 code = ICMP_UNREACH_HOST; 1943 break; 1944 1945 case EMSGSIZE: 1946 type = ICMP_UNREACH; 1947 code = ICMP_UNREACH_NEEDFRAG; 1948 #ifdef IPSEC 1949 /* 1950 * If the packet is routed over IPsec tunnel, tell the 1951 * originator the tunnel MTU. 1952 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1953 * XXX quickhack!!! 1954 */ 1955 if (cache_rt->ro_rt != NULL) { 1956 struct secpolicy *sp = NULL; 1957 int ipsecerror; 1958 int ipsechdr; 1959 struct route *ro; 1960 1961 sp = ipsec4_getpolicybyaddr(mcopy, 1962 IPSEC_DIR_OUTBOUND, 1963 IP_FORWARDING, 1964 &ipsecerror); 1965 1966 if (sp == NULL) 1967 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 1968 else { 1969 /* count IPsec header size */ 1970 ipsechdr = ipsec4_hdrsiz(mcopy, 1971 IPSEC_DIR_OUTBOUND, 1972 NULL); 1973 1974 /* 1975 * find the correct route for outer IPv4 1976 * header, compute tunnel MTU. 1977 * 1978 */ 1979 if (sp->req != NULL && sp->req->sav != NULL && 1980 sp->req->sav->sah != NULL) { 1981 ro = &sp->req->sav->sah->sa_route; 1982 if (ro->ro_rt != NULL && 1983 ro->ro_rt->rt_ifp != NULL) { 1984 destmtu = 1985 ro->ro_rt->rt_ifp->if_mtu; 1986 destmtu -= ipsechdr; 1987 } 1988 } 1989 1990 key_freesp(sp); 1991 } 1992 } 1993 #elif FAST_IPSEC 1994 /* 1995 * If the packet is routed over IPsec tunnel, tell the 1996 * originator the tunnel MTU. 1997 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1998 * XXX quickhack!!! 1999 */ 2000 if (cache_rt->ro_rt != NULL) { 2001 struct secpolicy *sp = NULL; 2002 int ipsecerror; 2003 int ipsechdr; 2004 struct route *ro; 2005 2006 sp = ipsec_getpolicybyaddr(mcopy, 2007 IPSEC_DIR_OUTBOUND, 2008 IP_FORWARDING, 2009 &ipsecerror); 2010 2011 if (sp == NULL) 2012 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2013 else { 2014 /* count IPsec header size */ 2015 ipsechdr = ipsec4_hdrsiz(mcopy, 2016 IPSEC_DIR_OUTBOUND, 2017 NULL); 2018 2019 /* 2020 * find the correct route for outer IPv4 2021 * header, compute tunnel MTU. 2022 */ 2023 2024 if (sp->req != NULL && 2025 sp->req->sav != NULL && 2026 sp->req->sav->sah != NULL) { 2027 ro = &sp->req->sav->sah->sa_route; 2028 if (ro->ro_rt != NULL && 2029 ro->ro_rt->rt_ifp != NULL) { 2030 destmtu = 2031 ro->ro_rt->rt_ifp->if_mtu; 2032 destmtu -= ipsechdr; 2033 } 2034 } 2035 2036 KEY_FREESP(&sp); 2037 } 2038 } 2039 #else /* !IPSEC && !FAST_IPSEC */ 2040 if (cache_rt->ro_rt != NULL) 2041 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2042 #endif /*IPSEC*/ 2043 ipstat.ips_cantfrag++; 2044 break; 2045 2046 case ENOBUFS: 2047 /* 2048 * A router should not generate ICMP_SOURCEQUENCH as 2049 * required in RFC1812 Requirements for IP Version 4 Routers. 2050 * Source quench could be a big problem under DoS attacks, 2051 * or if the underlying interface is rate-limited. 2052 * Those who need source quench packets may re-enable them 2053 * via the net.inet.ip.sendsourcequench sysctl. 2054 */ 2055 if (!ip_sendsourcequench) { 2056 m_freem(mcopy); 2057 return; 2058 } else { 2059 type = ICMP_SOURCEQUENCH; 2060 code = 0; 2061 } 2062 break; 2063 2064 case EACCES: /* ipfw denied packet */ 2065 m_freem(mcopy); 2066 return; 2067 } 2068 icmp_error(mcopy, type, code, dest, destmtu); 2069 } 2070 2071 void 2072 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2073 struct mbuf *m) 2074 { 2075 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2076 struct timeval tv; 2077 2078 microtime(&tv); 2079 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2080 SCM_TIMESTAMP, SOL_SOCKET); 2081 if (*mp) 2082 mp = &(*mp)->m_next; 2083 } 2084 if (inp->inp_flags & INP_RECVDSTADDR) { 2085 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2086 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2087 if (*mp) 2088 mp = &(*mp)->m_next; 2089 } 2090 if (inp->inp_flags & INP_RECVTTL) { 2091 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2092 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2093 if (*mp) 2094 mp = &(*mp)->m_next; 2095 } 2096 #ifdef notyet 2097 /* XXX 2098 * Moving these out of udp_input() made them even more broken 2099 * than they already were. 2100 */ 2101 /* options were tossed already */ 2102 if (inp->inp_flags & INP_RECVOPTS) { 2103 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2104 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2105 if (*mp) 2106 mp = &(*mp)->m_next; 2107 } 2108 /* ip_srcroute doesn't do what we want here, need to fix */ 2109 if (inp->inp_flags & INP_RECVRETOPTS) { 2110 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 2111 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2112 if (*mp) 2113 mp = &(*mp)->m_next; 2114 } 2115 #endif 2116 if (inp->inp_flags & INP_RECVIF) { 2117 struct ifnet *ifp; 2118 struct sdlbuf { 2119 struct sockaddr_dl sdl; 2120 u_char pad[32]; 2121 } sdlbuf; 2122 struct sockaddr_dl *sdp; 2123 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2124 2125 if (((ifp = m->m_pkthdr.rcvif)) && 2126 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2127 sdp = IF_LLSOCKADDR(ifp); 2128 /* 2129 * Change our mind and don't try copy. 2130 */ 2131 if ((sdp->sdl_family != AF_LINK) || 2132 (sdp->sdl_len > sizeof(sdlbuf))) { 2133 goto makedummy; 2134 } 2135 bcopy(sdp, sdl2, sdp->sdl_len); 2136 } else { 2137 makedummy: 2138 sdl2->sdl_len = 2139 offsetof(struct sockaddr_dl, sdl_data[0]); 2140 sdl2->sdl_family = AF_LINK; 2141 sdl2->sdl_index = 0; 2142 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2143 } 2144 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2145 IP_RECVIF, IPPROTO_IP); 2146 if (*mp) 2147 mp = &(*mp)->m_next; 2148 } 2149 } 2150 2151 /* 2152 * XXX these routines are called from the upper part of the kernel. 2153 * 2154 * They could also be moved to ip_mroute.c, since all the RSVP 2155 * handling is done there already. 2156 */ 2157 int 2158 ip_rsvp_init(struct socket *so) 2159 { 2160 if (so->so_type != SOCK_RAW || 2161 so->so_proto->pr_protocol != IPPROTO_RSVP) 2162 return EOPNOTSUPP; 2163 2164 if (ip_rsvpd != NULL) 2165 return EADDRINUSE; 2166 2167 ip_rsvpd = so; 2168 /* 2169 * This may seem silly, but we need to be sure we don't over-increment 2170 * the RSVP counter, in case something slips up. 2171 */ 2172 if (!ip_rsvp_on) { 2173 ip_rsvp_on = 1; 2174 rsvp_on++; 2175 } 2176 2177 return 0; 2178 } 2179 2180 int 2181 ip_rsvp_done(void) 2182 { 2183 ip_rsvpd = NULL; 2184 /* 2185 * This may seem silly, but we need to be sure we don't over-decrement 2186 * the RSVP counter, in case something slips up. 2187 */ 2188 if (ip_rsvp_on) { 2189 ip_rsvp_on = 0; 2190 rsvp_on--; 2191 } 2192 return 0; 2193 } 2194 2195 void 2196 rsvp_input(struct mbuf *m, ...) /* XXX must fixup manually */ 2197 { 2198 int off, proto; 2199 __va_list ap; 2200 2201 __va_start(ap, m); 2202 off = __va_arg(ap, int); 2203 proto = __va_arg(ap, int); 2204 __va_end(ap); 2205 2206 if (rsvp_input_p) { /* call the real one if loaded */ 2207 rsvp_input_p(m, off, proto); 2208 return; 2209 } 2210 2211 /* Can still get packets with rsvp_on = 0 if there is a local member 2212 * of the group to which the RSVP packet is addressed. But in this 2213 * case we want to throw the packet away. 2214 */ 2215 2216 if (!rsvp_on) { 2217 m_freem(m); 2218 return; 2219 } 2220 2221 if (ip_rsvpd != NULL) { 2222 rip_input(m, off, proto); 2223 return; 2224 } 2225 /* Drop the packet */ 2226 m_freem(m); 2227 } 2228