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) 2003, 2004 Jeffrey M. Hsu. All rights reserved. 36 * 37 * License terms: all terms for the DragonFly license above plus the following: 38 * 39 * 4. All advertising materials mentioning features or use of this software 40 * must display the following acknowledgement: 41 * 42 * This product includes software developed by Jeffrey M. Hsu 43 * for the DragonFly Project. 44 * 45 * This requirement may be waived with permission from Jeffrey Hsu. 46 * This requirement will sunset and may be removed on July 8 2005, 47 * after which the standard DragonFly license (as shown above) will 48 * apply. 49 */ 50 51 /* 52 * Copyright (c) 1982, 1986, 1988, 1993 53 * The Regents of the University of California. All rights reserved. 54 * 55 * Redistribution and use in source and binary forms, with or without 56 * modification, are permitted provided that the following conditions 57 * are met: 58 * 1. Redistributions of source code must retain the above copyright 59 * notice, this list of conditions and the following disclaimer. 60 * 2. Redistributions in binary form must reproduce the above copyright 61 * notice, this list of conditions and the following disclaimer in the 62 * documentation and/or other materials provided with the distribution. 63 * 3. All advertising materials mentioning features or use of this software 64 * must display the following acknowledgement: 65 * This product includes software developed by the University of 66 * California, Berkeley and its contributors. 67 * 4. Neither the name of the University nor the names of its contributors 68 * may be used to endorse or promote products derived from this software 69 * without specific prior written permission. 70 * 71 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 72 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 73 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 74 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 75 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 76 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 77 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 78 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 79 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 80 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 81 * SUCH DAMAGE. 82 * 83 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 84 * $FreeBSD: src/sys/netinet/ip_input.c,v 1.130.2.52 2003/03/07 07:01:28 silby Exp $ 85 * $DragonFly: src/sys/netinet/ip_input.c,v 1.43 2004/12/29 03:26:42 hsu Exp $ 86 */ 87 88 #define _IP_VHL 89 90 #include "opt_bootp.h" 91 #include "opt_ipfw.h" 92 #include "opt_ipdn.h" 93 #include "opt_ipdivert.h" 94 #include "opt_ipfilter.h" 95 #include "opt_ipstealth.h" 96 #include "opt_ipsec.h" 97 #include "opt_random_ip_id.h" 98 99 #include <sys/param.h> 100 #include <sys/systm.h> 101 #include <sys/mbuf.h> 102 #include <sys/malloc.h> 103 #include <sys/mpipe.h> 104 #include <sys/domain.h> 105 #include <sys/protosw.h> 106 #include <sys/socket.h> 107 #include <sys/time.h> 108 #include <sys/globaldata.h> 109 #include <sys/thread.h> 110 #include <sys/kernel.h> 111 #include <sys/syslog.h> 112 #include <sys/sysctl.h> 113 #include <sys/in_cksum.h> 114 115 #include <sys/thread2.h> 116 #include <sys/msgport2.h> 117 118 #include <machine/stdarg.h> 119 120 #include <net/if.h> 121 #include <net/if_types.h> 122 #include <net/if_var.h> 123 #include <net/if_dl.h> 124 #include <net/pfil.h> 125 #include <net/route.h> 126 #include <net/netisr.h> 127 #include <net/intrq.h> 128 129 #include <netinet/in.h> 130 #include <netinet/in_systm.h> 131 #include <netinet/in_var.h> 132 #include <netinet/ip.h> 133 #include <netinet/in_pcb.h> 134 #include <netinet/ip_var.h> 135 #include <netinet/ip_icmp.h> 136 137 138 #include <sys/socketvar.h> 139 140 #include <net/ipfw/ip_fw.h> 141 #include <net/dummynet/ip_dummynet.h> 142 143 #ifdef IPSEC 144 #include <netinet6/ipsec.h> 145 #include <netproto/key/key.h> 146 #endif 147 148 #ifdef FAST_IPSEC 149 #include <netproto/ipsec/ipsec.h> 150 #include <netproto/ipsec/key.h> 151 #endif 152 153 int rsvp_on = 0; 154 static int ip_rsvp_on; 155 struct socket *ip_rsvpd; 156 157 int ipforwarding = 0; 158 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 159 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 160 161 static int ipsendredirects = 1; /* XXX */ 162 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 163 &ipsendredirects, 0, "Enable sending IP redirects"); 164 165 int ip_defttl = IPDEFTTL; 166 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 167 &ip_defttl, 0, "Maximum TTL on IP packets"); 168 169 static int ip_dosourceroute = 0; 170 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 171 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 172 173 static int ip_acceptsourceroute = 0; 174 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 175 CTLFLAG_RW, &ip_acceptsourceroute, 0, 176 "Enable accepting source routed IP packets"); 177 178 static int ip_keepfaith = 0; 179 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 180 &ip_keepfaith, 0, 181 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 182 183 static int nipq = 0; /* total # of reass queues */ 184 static int maxnipq; 185 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 186 &maxnipq, 0, 187 "Maximum number of IPv4 fragment reassembly queue entries"); 188 189 static int maxfragsperpacket; 190 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 191 &maxfragsperpacket, 0, 192 "Maximum number of IPv4 fragments allowed per packet"); 193 194 static int ip_sendsourcequench = 0; 195 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 196 &ip_sendsourcequench, 0, 197 "Enable the transmission of source quench packets"); 198 199 /* 200 * XXX - Setting ip_checkinterface mostly implements the receive side of 201 * the Strong ES model described in RFC 1122, but since the routing table 202 * and transmit implementation do not implement the Strong ES model, 203 * setting this to 1 results in an odd hybrid. 204 * 205 * XXX - ip_checkinterface currently must be disabled if you use ipnat 206 * to translate the destination address to another local interface. 207 * 208 * XXX - ip_checkinterface must be disabled if you add IP aliases 209 * to the loopback interface instead of the interface where the 210 * packets for those addresses are received. 211 */ 212 static int ip_checkinterface = 0; 213 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 214 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 215 216 #ifdef DIAGNOSTIC 217 static int ipprintfs = 0; 218 #endif 219 220 static struct ifqueue ipintrq; 221 static int ipqmaxlen = IFQ_MAXLEN; 222 223 extern struct domain inetdomain; 224 extern struct protosw inetsw[]; 225 u_char ip_protox[IPPROTO_MAX]; 226 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 227 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 228 u_long in_ifaddrhmask; /* mask for hash table */ 229 230 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 231 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 232 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 233 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 234 235 struct ip_stats ipstats_ary[MAXCPU]; 236 #ifdef SMP 237 static int 238 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 239 { 240 int cpu, error = 0; 241 242 for (cpu = 0; cpu < ncpus; ++cpu) { 243 if ((error = SYSCTL_OUT(req, &ipstats_ary[cpu], 244 sizeof(struct ip_stats)))) 245 break; 246 if ((error = SYSCTL_IN(req, &ipstats_ary[cpu], 247 sizeof(struct ip_stats)))) 248 break; 249 } 250 251 return (error); 252 } 253 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 254 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 255 #else 256 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 257 &ipstat, ip_stats, "IP statistics"); 258 #endif 259 260 /* Packet reassembly stuff */ 261 #define IPREASS_NHASH_LOG2 6 262 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 263 #define IPREASS_HMASK (IPREASS_NHASH - 1) 264 #define IPREASS_HASH(x,y) \ 265 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 266 267 static struct ipq ipq[IPREASS_NHASH]; 268 const int ipintrq_present = 1; 269 270 #ifdef IPCTL_DEFMTU 271 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 272 &ip_mtu, 0, "Default MTU"); 273 #endif 274 275 #ifdef IPSTEALTH 276 static int ipstealth = 0; 277 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, ""); 278 #else 279 static const int ipstealth = 0; 280 #endif 281 282 283 /* Firewall hooks */ 284 ip_fw_chk_t *ip_fw_chk_ptr; 285 int fw_enable = 1; 286 int fw_one_pass = 1; 287 288 /* Dummynet hooks */ 289 ip_dn_io_t *ip_dn_io_ptr; 290 291 struct pfil_head inet_pfil_hook; 292 293 /* 294 * XXX this is ugly -- the following two global variables are 295 * used to store packet state while it travels through the stack. 296 * Note that the code even makes assumptions on the size and 297 * alignment of fields inside struct ip_srcrt so e.g. adding some 298 * fields will break the code. This needs to be fixed. 299 * 300 * We need to save the IP options in case a protocol wants to respond 301 * to an incoming packet over the same route if the packet got here 302 * using IP source routing. This allows connection establishment and 303 * maintenance when the remote end is on a network that is not known 304 * to us. 305 */ 306 static int ip_nhops = 0; 307 308 static struct ip_srcrt { 309 struct in_addr dst; /* final destination */ 310 char nop; /* one NOP to align */ 311 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 312 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 313 } ip_srcrt; 314 315 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 316 static struct malloc_pipe ipq_mpipe; 317 318 static void save_rte (u_char *, struct in_addr); 319 static int ip_dooptions (struct mbuf *m, int, 320 struct sockaddr_in *next_hop); 321 static void ip_forward (struct mbuf *m, int srcrt, 322 struct sockaddr_in *next_hop); 323 static void ip_freef (struct ipq *); 324 static int ip_input_handler (struct netmsg *); 325 static struct mbuf *ip_reass (struct mbuf *, struct ipq *, 326 struct ipq *, u_int32_t *, u_int16_t *); 327 328 /* 329 * IP initialization: fill in IP protocol switch table. 330 * All protocols not implemented in kernel go to raw IP protocol handler. 331 */ 332 void 333 ip_init(void) 334 { 335 struct protosw *pr; 336 int i; 337 #ifdef SMP 338 int cpu; 339 #endif 340 341 /* 342 * Make sure we can handle a reasonable number of fragments but 343 * cap it at 4000 (XXX). 344 */ 345 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 346 IFQ_MAXLEN, 4000, 0, NULL); 347 TAILQ_INIT(&in_ifaddrhead); 348 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 349 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 350 if (pr == NULL) 351 panic("ip_init"); 352 for (i = 0; i < IPPROTO_MAX; i++) 353 ip_protox[i] = pr - inetsw; 354 for (pr = inetdomain.dom_protosw; 355 pr < inetdomain.dom_protoswNPROTOSW; pr++) 356 if (pr->pr_domain->dom_family == PF_INET && 357 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 358 ip_protox[pr->pr_protocol] = pr - inetsw; 359 360 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 361 inet_pfil_hook.ph_af = AF_INET; 362 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) { 363 printf("%s: WARNING: unable to register pfil hook, " 364 "error %d\n", __func__, i); 365 } 366 367 for (i = 0; i < IPREASS_NHASH; i++) 368 ipq[i].next = ipq[i].prev = &ipq[i]; 369 370 maxnipq = nmbclusters / 32; 371 maxfragsperpacket = 16; 372 373 #ifndef RANDOM_IP_ID 374 ip_id = time_second & 0xffff; 375 #endif 376 ipintrq.ifq_maxlen = ipqmaxlen; 377 378 /* 379 * Initialize IP statistics. 380 * 381 * It is layed out as an array which is has one element for UP, 382 * and SMP_MAXCPU elements for SMP. This allows us to retain 383 * the access mechanism from userland for both UP and SMP. 384 */ 385 #ifdef SMP 386 for (cpu = 0; cpu < ncpus; ++cpu) { 387 bzero(&ipstats_ary[cpu], sizeof(struct ip_stats)); 388 } 389 #else 390 bzero(&ipstat, sizeof(struct ip_stats)); 391 #endif 392 393 netisr_register(NETISR_IP, ip_mport, ip_input_handler); 394 } 395 396 /* 397 * XXX watch out this one. It is perhaps used as a cache for 398 * the most recently used route ? it is cleared in in_addroute() 399 * when a new route is successfully created. 400 */ 401 struct route ipforward_rt; 402 403 /* Do transport protocol processing. */ 404 static void 405 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip, 406 struct sockaddr_in *nexthop) 407 { 408 /* 409 * Switch out to protocol's input routine. 410 */ 411 if (nexthop && ip->ip_p == IPPROTO_TCP) { 412 /* TCP needs IPFORWARD info if available */ 413 struct m_hdr tag; 414 415 tag.mh_type = MT_TAG; 416 tag.mh_flags = PACKET_TAG_IPFORWARD; 417 tag.mh_data = (caddr_t)nexthop; 418 tag.mh_next = m; 419 420 (*inetsw[ip_protox[ip->ip_p]].pr_input) 421 ((struct mbuf *)&tag, hlen, ip->ip_p); 422 } else { 423 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, ip->ip_p); 424 } 425 } 426 427 struct netmsg_transport_packet { 428 struct lwkt_msg nm_lmsg; 429 struct mbuf *nm_mbuf; 430 int nm_hlen; 431 boolean_t nm_hasnexthop; 432 struct sockaddr_in nm_nexthop; 433 }; 434 435 static int 436 transport_processing_handler(lwkt_msg_t lmsg) 437 { 438 struct netmsg_transport_packet *msg = (void *)lmsg; 439 struct sockaddr_in *nexthop; 440 struct ip *ip; 441 442 ip = mtod(msg->nm_mbuf, struct ip *); 443 nexthop = msg->nm_hasnexthop ? &msg->nm_nexthop : NULL; 444 transport_processing_oncpu(msg->nm_mbuf, msg->nm_hlen, ip, nexthop); 445 lwkt_replymsg(lmsg, 0); 446 return(EASYNC); 447 } 448 449 static int 450 ip_input_handler(struct netmsg *msg0) 451 { 452 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet; 453 454 ip_input(m); 455 lwkt_replymsg(&msg0->nm_lmsg, 0); 456 return(EASYNC); 457 } 458 459 /* 460 * Ip input routine. Checksum and byte swap header. If fragmented 461 * try to reassemble. Process options. Pass to next level. 462 */ 463 void 464 ip_input(struct mbuf *m) 465 { 466 struct ip *ip; 467 struct ipq *fp; 468 struct in_ifaddr *ia = NULL; 469 struct ifaddr *ifa; 470 int i, hlen, checkif; 471 u_short sum; 472 struct in_addr pkt_dst; 473 u_int32_t divert_info = 0; /* packet divert/tee info */ 474 struct ip_fw_args args; 475 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 476 boolean_t needredispatch = FALSE; 477 struct in_addr odst; /* original dst address(NAT) */ 478 #ifdef FAST_IPSEC 479 struct m_tag *mtag; 480 struct tdb_ident *tdbi; 481 struct secpolicy *sp; 482 int s, error; 483 #endif 484 485 args.eh = NULL; 486 args.oif = NULL; 487 args.rule = NULL; 488 args.divert_rule = 0; /* divert cookie */ 489 args.next_hop = NULL; 490 491 /* Grab info from MT_TAG mbufs prepended to the chain. */ 492 while (m != NULL && m->m_type == MT_TAG) { 493 switch(m->_m_tag_id) { 494 case PACKET_TAG_DUMMYNET: 495 args.rule = ((struct dn_pkt *)m)->rule; 496 break; 497 case PACKET_TAG_DIVERT: 498 args.divert_rule = (int)m->m_hdr.mh_data & 0xffff; 499 break; 500 case PACKET_TAG_IPFORWARD: 501 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 502 break; 503 default: 504 printf("ip_input: unrecognised MT_TAG tag %d\n", 505 m->_m_tag_id); 506 break; 507 } 508 m = m->m_next; 509 } 510 KASSERT(m != NULL && (m->m_flags & M_PKTHDR), ("ip_input: no HDR")); 511 512 if (args.rule != NULL) { /* dummynet already filtered us */ 513 ip = mtod(m, struct ip *); 514 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 515 goto iphack; 516 } 517 518 ipstat.ips_total++; 519 520 /* length checks already done in ip_demux() */ 521 KASSERT(m->m_len >= sizeof(ip), ("IP header not in one mbuf")); 522 523 ip = mtod(m, struct ip *); 524 525 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 526 ipstat.ips_badvers++; 527 goto bad; 528 } 529 530 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 531 /* length checks already done in ip_demux() */ 532 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 533 KASSERT(m->m_len >= hlen, ("packet shorter than IP header length")); 534 535 /* 127/8 must not appear on wire - RFC1122 */ 536 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 537 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 538 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 539 ipstat.ips_badaddr++; 540 goto bad; 541 } 542 } 543 544 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 545 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 546 } else { 547 if (hlen == sizeof(struct ip)) { 548 sum = in_cksum_hdr(ip); 549 } else { 550 sum = in_cksum(m, hlen); 551 } 552 } 553 if (sum != 0) { 554 ipstat.ips_badsum++; 555 goto bad; 556 } 557 558 /* 559 * Convert fields to host representation. 560 */ 561 ip->ip_len = ntohs(ip->ip_len); 562 if (ip->ip_len < hlen) { 563 ipstat.ips_badlen++; 564 goto bad; 565 } 566 ip->ip_off = ntohs(ip->ip_off); 567 568 /* 569 * Check that the amount of data in the buffers 570 * is as at least much as the IP header would have us expect. 571 * Trim mbufs if longer than we expect. 572 * Drop packet if shorter than we expect. 573 */ 574 if (m->m_pkthdr.len < ip->ip_len) { 575 ipstat.ips_tooshort++; 576 goto bad; 577 } 578 if (m->m_pkthdr.len > ip->ip_len) { 579 if (m->m_len == m->m_pkthdr.len) { 580 m->m_len = ip->ip_len; 581 m->m_pkthdr.len = ip->ip_len; 582 } else 583 m_adj(m, ip->ip_len - m->m_pkthdr.len); 584 } 585 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 586 /* 587 * Bypass packet filtering for packets from a tunnel (gif). 588 */ 589 if (ipsec_gethist(m, NULL)) 590 goto pass; 591 #endif 592 593 /* 594 * IpHack's section. 595 * Right now when no processing on packet has done 596 * and it is still fresh out of network we do our black 597 * deals with it. 598 * - Firewall: deny/allow/divert 599 * - Xlate: translate packet's addr/port (NAT). 600 * - Pipe: pass pkt through dummynet. 601 * - Wrap: fake packet's addr/port <unimpl.> 602 * - Encapsulate: put it in another IP and send out. <unimp.> 603 */ 604 605 iphack: 606 607 /* 608 * Run through list of hooks for input packets. 609 * 610 * NB: Beware of the destination address changing (e.g. 611 * by NAT rewriting). When this happens, tell 612 * ip_forward to do the right thing. 613 */ 614 if (pfil_has_hooks(&inet_pfil_hook)) { 615 odst = ip->ip_dst; 616 if (pfil_run_hooks(&inet_pfil_hook, &m, 617 m->m_pkthdr.rcvif, PFIL_IN)) { 618 return; 619 } 620 if (m == NULL) /* consumed by filter */ 621 return; 622 ip = mtod(m, struct ip *); 623 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 624 } 625 626 if (fw_enable && IPFW_LOADED) { 627 /* 628 * If we've been forwarded from the output side, then 629 * skip the firewall a second time 630 */ 631 if (args.next_hop != NULL) 632 goto ours; 633 634 args.m = m; 635 i = ip_fw_chk_ptr(&args); 636 m = args.m; 637 638 if ((i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 639 if (m != NULL) 640 m_freem(m); 641 return; 642 } 643 ip = mtod(m, struct ip *); /* just in case m changed */ 644 if (i == 0 && args.next_hop == NULL) /* common case */ 645 goto pass; 646 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG)) { 647 /* Send packet to the appropriate pipe */ 648 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 649 return; 650 } 651 #ifdef IPDIVERT 652 if (i != 0 && !(i & IP_FW_PORT_DYNT_FLAG)) { 653 /* Divert or tee packet */ 654 divert_info = i; 655 goto ours; 656 } 657 #endif 658 if (i == 0 && args.next_hop != NULL) 659 goto pass; 660 /* 661 * if we get here, the packet must be dropped 662 */ 663 m_freem(m); 664 return; 665 } 666 pass: 667 668 /* 669 * Process options and, if not destined for us, 670 * ship it on. ip_dooptions returns 1 when an 671 * error was detected (causing an icmp message 672 * to be sent and the original packet to be freed). 673 */ 674 ip_nhops = 0; /* for source routed packets */ 675 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, args.next_hop)) 676 return; 677 678 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 679 * matter if it is destined to another node, or whether it is 680 * a multicast one, RSVP wants it! and prevents it from being forwarded 681 * anywhere else. Also checks if the rsvp daemon is running before 682 * grabbing the packet. 683 */ 684 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 685 goto ours; 686 687 /* 688 * Check our list of addresses, to see if the packet is for us. 689 * If we don't have any addresses, assume any unicast packet 690 * we receive might be for us (and let the upper layers deal 691 * with it). 692 */ 693 if (TAILQ_EMPTY(&in_ifaddrhead) && !(m->m_flags & (M_MCAST | M_BCAST))) 694 goto ours; 695 696 /* 697 * Cache the destination address of the packet; this may be 698 * changed by use of 'ipfw fwd'. 699 */ 700 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 701 702 /* 703 * Enable a consistency check between the destination address 704 * and the arrival interface for a unicast packet (the RFC 1122 705 * strong ES model) if IP forwarding is disabled and the packet 706 * is not locally generated and the packet is not subject to 707 * 'ipfw fwd'. 708 * 709 * XXX - Checking also should be disabled if the destination 710 * address is ipnat'ed to a different interface. 711 * 712 * XXX - Checking is incompatible with IP aliases added 713 * to the loopback interface instead of the interface where 714 * the packets are received. 715 */ 716 checkif = ip_checkinterface && 717 !ipforwarding && 718 m->m_pkthdr.rcvif != NULL && 719 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 720 (args.next_hop == NULL); 721 722 /* 723 * Check for exact addresses in the hash bucket. 724 */ 725 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 726 /* 727 * If the address matches, verify that the packet 728 * arrived via the correct interface if checking is 729 * enabled. 730 */ 731 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 732 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 733 goto ours; 734 } 735 /* 736 * Check for broadcast addresses. 737 * 738 * Only accept broadcast packets that arrive via the matching 739 * interface. Reception of forwarded directed broadcasts would 740 * be handled via ip_forward() and ether_output() with the loopback 741 * into the stack for SIMPLEX interfaces handled by ether_output(). 742 */ 743 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 744 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 745 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 746 continue; 747 if (ifa->ifa_addr->sa_family != AF_INET) 748 continue; 749 ia = ifatoia(ifa); 750 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 751 pkt_dst.s_addr) 752 goto ours; 753 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 754 goto ours; 755 #ifdef BOOTP_COMPAT 756 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 757 goto ours; 758 #endif 759 } 760 } 761 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 762 struct in_multi *inm; 763 764 if (ip_mrouter != NULL) { 765 /* 766 * If we are acting as a multicast router, all 767 * incoming multicast packets are passed to the 768 * kernel-level multicast forwarding function. 769 * The packet is returned (relatively) intact; if 770 * ip_mforward() returns a non-zero value, the packet 771 * must be discarded, else it may be accepted below. 772 */ 773 if (ip_mforward != NULL && 774 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 775 ipstat.ips_cantforward++; 776 m_freem(m); 777 return; 778 } 779 780 /* 781 * The process-level routing daemon needs to receive 782 * all multicast IGMP packets, whether or not this 783 * host belongs to their destination groups. 784 */ 785 if (ip->ip_p == IPPROTO_IGMP) 786 goto ours; 787 ipstat.ips_forward++; 788 } 789 /* 790 * See if we belong to the destination multicast group on the 791 * arrival interface. 792 */ 793 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 794 if (inm == NULL) { 795 ipstat.ips_notmember++; 796 m_freem(m); 797 return; 798 } 799 goto ours; 800 } 801 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 802 goto ours; 803 if (ip->ip_dst.s_addr == INADDR_ANY) 804 goto ours; 805 806 /* 807 * FAITH(Firewall Aided Internet Translator) 808 */ 809 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 810 if (ip_keepfaith) { 811 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 812 goto ours; 813 } 814 m_freem(m); 815 return; 816 } 817 818 /* 819 * Not for us; forward if possible and desirable. 820 */ 821 if (!ipforwarding) { 822 ipstat.ips_cantforward++; 823 m_freem(m); 824 } else { 825 #ifdef IPSEC 826 /* 827 * Enforce inbound IPsec SPD. 828 */ 829 if (ipsec4_in_reject(m, NULL)) { 830 ipsecstat.in_polvio++; 831 goto bad; 832 } 833 #endif 834 #ifdef FAST_IPSEC 835 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 836 s = splnet(); 837 if (mtag != NULL) { 838 tdbi = (struct tdb_ident *)(mtag + 1); 839 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 840 } else { 841 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 842 IP_FORWARDING, &error); 843 } 844 if (sp == NULL) { /* NB: can happen if error */ 845 splx(s); 846 /*XXX error stat???*/ 847 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 848 goto bad; 849 } 850 851 /* 852 * Check security policy against packet attributes. 853 */ 854 error = ipsec_in_reject(sp, m); 855 KEY_FREESP(&sp); 856 splx(s); 857 if (error) { 858 ipstat.ips_cantforward++; 859 goto bad; 860 } 861 #endif 862 ip_forward(m, using_srcrt, args.next_hop); 863 } 864 return; 865 866 ours: 867 868 /* 869 * IPSTEALTH: Process non-routing options only 870 * if the packet is destined for us. 871 */ 872 if (ipstealth && 873 hlen > sizeof(struct ip) && 874 ip_dooptions(m, 1, args.next_hop)) 875 return; 876 877 /* Count the packet in the ip address stats */ 878 if (ia != NULL) { 879 ia->ia_ifa.if_ipackets++; 880 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 881 } 882 883 /* 884 * If offset or IP_MF are set, must reassemble. 885 * Otherwise, nothing need be done. 886 * (We could look in the reassembly queue to see 887 * if the packet was previously fragmented, 888 * but it's not worth the time; just let them time out.) 889 */ 890 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 891 892 /* If maxnipq is 0, never accept fragments. */ 893 if (maxnipq == 0) { 894 ipstat.ips_fragments++; 895 ipstat.ips_fragdropped++; 896 goto bad; 897 } 898 899 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 900 /* 901 * Look for queue of fragments 902 * of this datagram. 903 */ 904 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 905 if (ip->ip_id == fp->ipq_id && 906 ip->ip_src.s_addr == fp->ipq_src.s_addr && 907 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 908 ip->ip_p == fp->ipq_p) 909 goto found; 910 911 fp = NULL; 912 913 /* 914 * Enforce upper bound on number of fragmented packets 915 * for which we attempt reassembly; 916 * If maxnipq is -1, accept all fragments without limitation. 917 */ 918 if ((nipq > maxnipq) && (maxnipq > 0)) { 919 /* 920 * drop something from the tail of the current queue 921 * before proceeding further 922 */ 923 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 924 for (i = 0; i < IPREASS_NHASH; i++) { 925 if (ipq[i].prev != &ipq[i]) { 926 ipstat.ips_fragtimeout += 927 ipq[i].prev->ipq_nfrags; 928 ip_freef(ipq[i].prev); 929 break; 930 } 931 } 932 } else { 933 ipstat.ips_fragtimeout += 934 ipq[sum].prev->ipq_nfrags; 935 ip_freef(ipq[sum].prev); 936 } 937 } 938 found: 939 /* 940 * Adjust ip_len to not reflect header, 941 * convert offset of this to bytes. 942 */ 943 ip->ip_len -= hlen; 944 if (ip->ip_off & IP_MF) { 945 /* 946 * Make sure that fragments have a data length 947 * that's a non-zero multiple of 8 bytes. 948 */ 949 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 950 ipstat.ips_toosmall++; /* XXX */ 951 goto bad; 952 } 953 m->m_flags |= M_FRAG; 954 } else 955 m->m_flags &= ~M_FRAG; 956 ip->ip_off <<= 3; 957 958 /* 959 * Attempt reassembly; if it succeeds, proceed. 960 * ip_reass() will return a different mbuf, and update 961 * the divert info in divert_info and args.divert_rule. 962 */ 963 ipstat.ips_fragments++; 964 m->m_pkthdr.header = ip; 965 m = ip_reass(m, fp, &ipq[sum], &divert_info, &args.divert_rule); 966 if (m == NULL) 967 return; 968 ipstat.ips_reassembled++; 969 needredispatch = TRUE; 970 ip = mtod(m, struct ip *); 971 /* Get the header length of the reassembled packet */ 972 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 973 #ifdef IPDIVERT 974 /* Restore original checksum before diverting packet */ 975 if (divert_info != 0) { 976 ip->ip_len += hlen; 977 ip->ip_len = htons(ip->ip_len); 978 ip->ip_off = htons(ip->ip_off); 979 ip->ip_sum = 0; 980 if (hlen == sizeof(struct ip)) 981 ip->ip_sum = in_cksum_hdr(ip); 982 else 983 ip->ip_sum = in_cksum(m, hlen); 984 ip->ip_off = ntohs(ip->ip_off); 985 ip->ip_len = ntohs(ip->ip_len); 986 ip->ip_len -= hlen; 987 } 988 #endif 989 } else { 990 ip->ip_len -= hlen; 991 } 992 993 #ifdef IPDIVERT 994 /* 995 * Divert or tee packet to the divert protocol if required. 996 */ 997 if (divert_info != 0) { 998 struct mbuf *clone = NULL; 999 1000 /* Clone packet if we're doing a 'tee' */ 1001 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 1002 clone = m_dup(m, MB_DONTWAIT); 1003 1004 /* Restore packet header fields to original values */ 1005 ip->ip_len += hlen; 1006 ip->ip_len = htons(ip->ip_len); 1007 ip->ip_off = htons(ip->ip_off); 1008 1009 /* Deliver packet to divert input routine */ 1010 divert_packet(m, 1, divert_info & 0xffff, args.divert_rule); 1011 ipstat.ips_delivered++; 1012 1013 /* If 'tee', continue with original packet */ 1014 if (clone == NULL) 1015 return; 1016 m = clone; 1017 ip = mtod(m, struct ip *); 1018 ip->ip_len += hlen; 1019 /* 1020 * Jump backwards to complete processing of the 1021 * packet. But first clear divert_info to avoid 1022 * entering this block again. 1023 * We do not need to clear args.divert_rule 1024 * or args.next_hop as they will not be used. 1025 */ 1026 divert_info = 0; 1027 goto pass; 1028 } 1029 #endif 1030 1031 #ifdef IPSEC 1032 /* 1033 * enforce IPsec policy checking if we are seeing last header. 1034 * note that we do not visit this with protocols with pcb layer 1035 * code - like udp/tcp/raw ip. 1036 */ 1037 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 1038 ipsec4_in_reject(m, NULL)) { 1039 ipsecstat.in_polvio++; 1040 goto bad; 1041 } 1042 #endif 1043 #if FAST_IPSEC 1044 /* 1045 * enforce IPsec policy checking if we are seeing last header. 1046 * note that we do not visit this with protocols with pcb layer 1047 * code - like udp/tcp/raw ip. 1048 */ 1049 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 1050 /* 1051 * Check if the packet has already had IPsec processing 1052 * done. If so, then just pass it along. This tag gets 1053 * set during AH, ESP, etc. input handling, before the 1054 * packet is returned to the ip input queue for delivery. 1055 */ 1056 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 1057 s = splnet(); 1058 if (mtag != NULL) { 1059 tdbi = (struct tdb_ident *)(mtag + 1); 1060 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 1061 } else { 1062 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 1063 IP_FORWARDING, &error); 1064 } 1065 if (sp != NULL) { 1066 /* 1067 * Check security policy against packet attributes. 1068 */ 1069 error = ipsec_in_reject(sp, m); 1070 KEY_FREESP(&sp); 1071 } else { 1072 /* XXX error stat??? */ 1073 error = EINVAL; 1074 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 1075 goto bad; 1076 } 1077 splx(s); 1078 if (error) 1079 goto bad; 1080 } 1081 #endif /* FAST_IPSEC */ 1082 1083 ipstat.ips_delivered++; 1084 if (needredispatch) { 1085 struct netmsg_transport_packet *msg; 1086 lwkt_port_t port; 1087 1088 msg = malloc(sizeof(struct netmsg_transport_packet), 1089 M_LWKTMSG, M_INTWAIT | M_NULLOK); 1090 if (msg == NULL) 1091 goto bad; 1092 1093 lwkt_initmsg(&msg->nm_lmsg, &netisr_afree_rport, 0, 1094 lwkt_cmd_func(transport_processing_handler), 1095 lwkt_cmd_op_none); 1096 msg->nm_hlen = hlen; 1097 msg->nm_hasnexthop = (args.next_hop != NULL); 1098 if (msg->nm_hasnexthop) 1099 msg->nm_nexthop = *args.next_hop; /* structure copy */ 1100 1101 ip->ip_off = htons(ip->ip_off); 1102 ip->ip_len = htons(ip->ip_len); 1103 port = ip_mport(&m); 1104 if (port) { 1105 msg->nm_mbuf = m; 1106 ip = mtod(m, struct ip *); 1107 ip->ip_len = ntohs(ip->ip_len); 1108 ip->ip_off = ntohs(ip->ip_off); 1109 lwkt_sendmsg(port, &msg->nm_lmsg); 1110 } 1111 } else { 1112 transport_processing_oncpu(m, hlen, ip, args.next_hop); 1113 } 1114 return; 1115 1116 bad: 1117 m_freem(m); 1118 } 1119 1120 /* 1121 * Take incoming datagram fragment and try to reassemble it into 1122 * whole datagram. If a chain for reassembly of this datagram already 1123 * exists, then it is given as fp; otherwise have to make a chain. 1124 * 1125 * When IPDIVERT enabled, keep additional state with each packet that 1126 * tells us if we need to divert or tee the packet we're building. 1127 * In particular, *divinfo includes the port and TEE flag, 1128 * *divert_rule is the number of the matching rule. 1129 */ 1130 1131 static struct mbuf * 1132 ip_reass(struct mbuf *m, struct ipq *fp, struct ipq *where, 1133 u_int32_t *divinfo, u_int16_t *divert_rule) 1134 { 1135 struct ip *ip = mtod(m, struct ip *); 1136 struct mbuf *p = NULL, *q, *nq; 1137 struct mbuf *n; 1138 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 1139 int i, next; 1140 1141 /* 1142 * Presence of header sizes in mbufs 1143 * would confuse code below. 1144 */ 1145 m->m_data += hlen; 1146 m->m_len -= hlen; 1147 1148 /* 1149 * If first fragment to arrive, create a reassembly queue. 1150 */ 1151 if (fp == NULL) { 1152 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1153 goto dropfrag; 1154 insque(fp, where); 1155 nipq++; 1156 fp->ipq_nfrags = 1; 1157 fp->ipq_ttl = IPFRAGTTL; 1158 fp->ipq_p = ip->ip_p; 1159 fp->ipq_id = ip->ip_id; 1160 fp->ipq_src = ip->ip_src; 1161 fp->ipq_dst = ip->ip_dst; 1162 fp->ipq_frags = m; 1163 m->m_nextpkt = NULL; 1164 #ifdef IPDIVERT 1165 fp->ipq_div_info = 0; 1166 fp->ipq_div_cookie = 0; 1167 #endif 1168 goto inserted; 1169 } else { 1170 fp->ipq_nfrags++; 1171 } 1172 1173 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1174 1175 /* 1176 * Find a segment which begins after this one does. 1177 */ 1178 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1179 if (GETIP(q)->ip_off > ip->ip_off) 1180 break; 1181 1182 /* 1183 * If there is a preceding segment, it may provide some of 1184 * our data already. If so, drop the data from the incoming 1185 * segment. If it provides all of our data, drop us, otherwise 1186 * stick new segment in the proper place. 1187 * 1188 * If some of the data is dropped from the the preceding 1189 * segment, then it's checksum is invalidated. 1190 */ 1191 if (p) { 1192 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1193 if (i > 0) { 1194 if (i >= ip->ip_len) 1195 goto dropfrag; 1196 m_adj(m, i); 1197 m->m_pkthdr.csum_flags = 0; 1198 ip->ip_off += i; 1199 ip->ip_len -= i; 1200 } 1201 m->m_nextpkt = p->m_nextpkt; 1202 p->m_nextpkt = m; 1203 } else { 1204 m->m_nextpkt = fp->ipq_frags; 1205 fp->ipq_frags = m; 1206 } 1207 1208 /* 1209 * While we overlap succeeding segments trim them or, 1210 * if they are completely covered, dequeue them. 1211 */ 1212 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1213 q = nq) { 1214 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1215 if (i < GETIP(q)->ip_len) { 1216 GETIP(q)->ip_len -= i; 1217 GETIP(q)->ip_off += i; 1218 m_adj(q, i); 1219 q->m_pkthdr.csum_flags = 0; 1220 break; 1221 } 1222 nq = q->m_nextpkt; 1223 m->m_nextpkt = nq; 1224 ipstat.ips_fragdropped++; 1225 fp->ipq_nfrags--; 1226 m_freem(q); 1227 } 1228 1229 inserted: 1230 1231 #ifdef IPDIVERT 1232 /* 1233 * Transfer firewall instructions to the fragment structure. 1234 * Only trust info in the fragment at offset 0. 1235 */ 1236 if (ip->ip_off == 0) { 1237 fp->ipq_div_info = *divinfo; 1238 fp->ipq_div_cookie = *divert_rule; 1239 } 1240 *divinfo = 0; 1241 *divert_rule = 0; 1242 #endif 1243 1244 /* 1245 * Check for complete reassembly and perform frag per packet 1246 * limiting. 1247 * 1248 * Frag limiting is performed here so that the nth frag has 1249 * a chance to complete the packet before we drop the packet. 1250 * As a result, n+1 frags are actually allowed per packet, but 1251 * only n will ever be stored. (n = maxfragsperpacket.) 1252 * 1253 */ 1254 next = 0; 1255 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1256 if (GETIP(q)->ip_off != next) { 1257 if (fp->ipq_nfrags > maxfragsperpacket) { 1258 ipstat.ips_fragdropped += fp->ipq_nfrags; 1259 ip_freef(fp); 1260 } 1261 return (NULL); 1262 } 1263 next += GETIP(q)->ip_len; 1264 } 1265 /* Make sure the last packet didn't have the IP_MF flag */ 1266 if (p->m_flags & M_FRAG) { 1267 if (fp->ipq_nfrags > maxfragsperpacket) { 1268 ipstat.ips_fragdropped += fp->ipq_nfrags; 1269 ip_freef(fp); 1270 } 1271 return (NULL); 1272 } 1273 1274 /* 1275 * Reassembly is complete. Make sure the packet is a sane size. 1276 */ 1277 q = fp->ipq_frags; 1278 ip = GETIP(q); 1279 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1280 ipstat.ips_toolong++; 1281 ipstat.ips_fragdropped += fp->ipq_nfrags; 1282 ip_freef(fp); 1283 return (NULL); 1284 } 1285 1286 /* 1287 * Concatenate fragments. 1288 */ 1289 m = q; 1290 n = m->m_next; 1291 m->m_next = NULL; 1292 m_cat(m, n); 1293 nq = q->m_nextpkt; 1294 q->m_nextpkt = NULL; 1295 for (q = nq; q != NULL; q = nq) { 1296 nq = q->m_nextpkt; 1297 q->m_nextpkt = NULL; 1298 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1299 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1300 m_cat(m, q); 1301 } 1302 1303 #ifdef IPDIVERT 1304 /* 1305 * Extract firewall instructions from the fragment structure. 1306 */ 1307 *divinfo = fp->ipq_div_info; 1308 *divert_rule = fp->ipq_div_cookie; 1309 #endif 1310 1311 /* 1312 * Create header for new ip packet by 1313 * modifying header of first packet; 1314 * dequeue and discard fragment reassembly header. 1315 * Make header visible. 1316 */ 1317 ip->ip_len = next; 1318 ip->ip_src = fp->ipq_src; 1319 ip->ip_dst = fp->ipq_dst; 1320 remque(fp); 1321 nipq--; 1322 mpipe_free(&ipq_mpipe, fp); 1323 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1324 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1325 /* some debugging cruft by sklower, below, will go away soon */ 1326 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1327 int plen = 0; 1328 1329 for (n = m; n; n = n->m_next) 1330 plen += n->m_len; 1331 m->m_pkthdr.len = plen; 1332 } 1333 return (m); 1334 1335 dropfrag: 1336 #ifdef IPDIVERT 1337 *divinfo = 0; 1338 *divert_rule = 0; 1339 #endif 1340 ipstat.ips_fragdropped++; 1341 if (fp != NULL) 1342 fp->ipq_nfrags--; 1343 m_freem(m); 1344 return (NULL); 1345 1346 #undef GETIP 1347 } 1348 1349 /* 1350 * Free a fragment reassembly header and all 1351 * associated datagrams. 1352 */ 1353 static void 1354 ip_freef(struct ipq *fp) 1355 { 1356 struct mbuf *q; 1357 1358 while (fp->ipq_frags) { 1359 q = fp->ipq_frags; 1360 fp->ipq_frags = q->m_nextpkt; 1361 m_freem(q); 1362 } 1363 remque(fp); 1364 mpipe_free(&ipq_mpipe, fp); 1365 nipq--; 1366 } 1367 1368 /* 1369 * IP timer processing; 1370 * if a timer expires on a reassembly 1371 * queue, discard it. 1372 */ 1373 void 1374 ip_slowtimo(void) 1375 { 1376 struct ipq *fp; 1377 int s = splnet(); 1378 int i; 1379 1380 for (i = 0; i < IPREASS_NHASH; i++) { 1381 fp = ipq[i].next; 1382 if (fp == NULL) 1383 continue; 1384 while (fp != &ipq[i]) { 1385 --fp->ipq_ttl; 1386 fp = fp->next; 1387 if (fp->prev->ipq_ttl == 0) { 1388 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1389 ip_freef(fp->prev); 1390 } 1391 } 1392 } 1393 /* 1394 * If we are over the maximum number of fragments 1395 * (due to the limit being lowered), drain off 1396 * enough to get down to the new limit. 1397 */ 1398 if (maxnipq >= 0 && nipq > maxnipq) { 1399 for (i = 0; i < IPREASS_NHASH; i++) { 1400 while (nipq > maxnipq && 1401 (ipq[i].next != &ipq[i])) { 1402 ipstat.ips_fragdropped += 1403 ipq[i].next->ipq_nfrags; 1404 ip_freef(ipq[i].next); 1405 } 1406 } 1407 } 1408 ipflow_slowtimo(); 1409 splx(s); 1410 } 1411 1412 /* 1413 * Drain off all datagram fragments. 1414 */ 1415 void 1416 ip_drain(void) 1417 { 1418 int i; 1419 1420 for (i = 0; i < IPREASS_NHASH; i++) { 1421 while (ipq[i].next != &ipq[i]) { 1422 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1423 ip_freef(ipq[i].next); 1424 } 1425 } 1426 in_rtqdrain(); 1427 } 1428 1429 /* 1430 * Do option processing on a datagram, 1431 * possibly discarding it if bad options are encountered, 1432 * or forwarding it if source-routed. 1433 * The pass argument is used when operating in the IPSTEALTH 1434 * mode to tell what options to process: 1435 * [LS]SRR (pass 0) or the others (pass 1). 1436 * The reason for as many as two passes is that when doing IPSTEALTH, 1437 * non-routing options should be processed only if the packet is for us. 1438 * Returns 1 if packet has been forwarded/freed, 1439 * 0 if the packet should be processed further. 1440 */ 1441 static int 1442 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1443 { 1444 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1445 struct ip *ip = mtod(m, struct ip *); 1446 u_char *cp; 1447 struct in_ifaddr *ia; 1448 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1449 boolean_t forward = FALSE; 1450 struct in_addr *sin, dst; 1451 n_time ntime; 1452 1453 dst = ip->ip_dst; 1454 cp = (u_char *)(ip + 1); 1455 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1456 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1457 opt = cp[IPOPT_OPTVAL]; 1458 if (opt == IPOPT_EOL) 1459 break; 1460 if (opt == IPOPT_NOP) 1461 optlen = 1; 1462 else { 1463 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1464 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1465 goto bad; 1466 } 1467 optlen = cp[IPOPT_OLEN]; 1468 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1469 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1470 goto bad; 1471 } 1472 } 1473 switch (opt) { 1474 1475 default: 1476 break; 1477 1478 /* 1479 * Source routing with record. 1480 * Find interface with current destination address. 1481 * If none on this machine then drop if strictly routed, 1482 * or do nothing if loosely routed. 1483 * Record interface address and bring up next address 1484 * component. If strictly routed make sure next 1485 * address is on directly accessible net. 1486 */ 1487 case IPOPT_LSRR: 1488 case IPOPT_SSRR: 1489 if (ipstealth && pass > 0) 1490 break; 1491 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1492 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1493 goto bad; 1494 } 1495 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1496 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1497 goto bad; 1498 } 1499 ipaddr.sin_addr = ip->ip_dst; 1500 ia = (struct in_ifaddr *) 1501 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1502 if (ia == NULL) { 1503 if (opt == IPOPT_SSRR) { 1504 type = ICMP_UNREACH; 1505 code = ICMP_UNREACH_SRCFAIL; 1506 goto bad; 1507 } 1508 if (!ip_dosourceroute) 1509 goto nosourcerouting; 1510 /* 1511 * Loose routing, and not at next destination 1512 * yet; nothing to do except forward. 1513 */ 1514 break; 1515 } 1516 off--; /* 0 origin */ 1517 if (off > optlen - (int)sizeof(struct in_addr)) { 1518 /* 1519 * End of source route. Should be for us. 1520 */ 1521 if (!ip_acceptsourceroute) 1522 goto nosourcerouting; 1523 save_rte(cp, ip->ip_src); 1524 break; 1525 } 1526 if (ipstealth) 1527 goto dropit; 1528 if (!ip_dosourceroute) { 1529 if (ipforwarding) { 1530 char buf[sizeof "aaa.bbb.ccc.ddd"]; 1531 1532 /* 1533 * Acting as a router, so generate ICMP 1534 */ 1535 nosourcerouting: 1536 strcpy(buf, inet_ntoa(ip->ip_dst)); 1537 log(LOG_WARNING, 1538 "attempted source route from %s to %s\n", 1539 inet_ntoa(ip->ip_src), buf); 1540 type = ICMP_UNREACH; 1541 code = ICMP_UNREACH_SRCFAIL; 1542 goto bad; 1543 } else { 1544 /* 1545 * Not acting as a router, 1546 * so silently drop. 1547 */ 1548 dropit: 1549 ipstat.ips_cantforward++; 1550 m_freem(m); 1551 return (1); 1552 } 1553 } 1554 1555 /* 1556 * locate outgoing interface 1557 */ 1558 memcpy(&ipaddr.sin_addr, cp + off, 1559 sizeof ipaddr.sin_addr); 1560 1561 if (opt == IPOPT_SSRR) { 1562 #define INA struct in_ifaddr * 1563 #define SA struct sockaddr * 1564 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1565 == NULL) 1566 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1567 } else 1568 ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt); 1569 if (ia == NULL) { 1570 type = ICMP_UNREACH; 1571 code = ICMP_UNREACH_SRCFAIL; 1572 goto bad; 1573 } 1574 ip->ip_dst = ipaddr.sin_addr; 1575 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1576 sizeof(struct in_addr)); 1577 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1578 /* 1579 * Let ip_intr's mcast routing check handle mcast pkts 1580 */ 1581 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1582 break; 1583 1584 case IPOPT_RR: 1585 if (ipstealth && pass == 0) 1586 break; 1587 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1588 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1589 goto bad; 1590 } 1591 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1592 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1593 goto bad; 1594 } 1595 /* 1596 * If no space remains, ignore. 1597 */ 1598 off--; /* 0 origin */ 1599 if (off > optlen - (int)sizeof(struct in_addr)) 1600 break; 1601 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1602 sizeof ipaddr.sin_addr); 1603 /* 1604 * locate outgoing interface; if we're the destination, 1605 * use the incoming interface (should be same). 1606 */ 1607 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1608 (ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt)) 1609 == NULL) { 1610 type = ICMP_UNREACH; 1611 code = ICMP_UNREACH_HOST; 1612 goto bad; 1613 } 1614 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1615 sizeof(struct in_addr)); 1616 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1617 break; 1618 1619 case IPOPT_TS: 1620 if (ipstealth && pass == 0) 1621 break; 1622 code = cp - (u_char *)ip; 1623 if (optlen < 4 || optlen > 40) { 1624 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1625 goto bad; 1626 } 1627 if ((off = cp[IPOPT_OFFSET]) < 5) { 1628 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1629 goto bad; 1630 } 1631 if (off > optlen - (int)sizeof(int32_t)) { 1632 cp[IPOPT_OFFSET + 1] += (1 << 4); 1633 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1634 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1635 goto bad; 1636 } 1637 break; 1638 } 1639 off--; /* 0 origin */ 1640 sin = (struct in_addr *)(cp + off); 1641 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1642 1643 case IPOPT_TS_TSONLY: 1644 break; 1645 1646 case IPOPT_TS_TSANDADDR: 1647 if (off + sizeof(n_time) + 1648 sizeof(struct in_addr) > optlen) { 1649 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1650 goto bad; 1651 } 1652 ipaddr.sin_addr = dst; 1653 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1654 m->m_pkthdr.rcvif); 1655 if (ia == NULL) 1656 continue; 1657 memcpy(sin, &IA_SIN(ia)->sin_addr, 1658 sizeof(struct in_addr)); 1659 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1660 off += sizeof(struct in_addr); 1661 break; 1662 1663 case IPOPT_TS_PRESPEC: 1664 if (off + sizeof(n_time) + 1665 sizeof(struct in_addr) > optlen) { 1666 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1667 goto bad; 1668 } 1669 memcpy(&ipaddr.sin_addr, sin, 1670 sizeof(struct in_addr)); 1671 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1672 continue; 1673 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1674 off += sizeof(struct in_addr); 1675 break; 1676 1677 default: 1678 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1679 goto bad; 1680 } 1681 ntime = iptime(); 1682 memcpy(cp + off, &ntime, sizeof(n_time)); 1683 cp[IPOPT_OFFSET] += sizeof(n_time); 1684 } 1685 } 1686 if (forward && ipforwarding) { 1687 ip_forward(m, 1, next_hop); 1688 return (1); 1689 } 1690 return (0); 1691 bad: 1692 icmp_error(m, type, code, 0, NULL); 1693 ipstat.ips_badoptions++; 1694 return (1); 1695 } 1696 1697 /* 1698 * Given address of next destination (final or next hop), 1699 * return internet address info of interface to be used to get there. 1700 */ 1701 struct in_ifaddr * 1702 ip_rtaddr(struct in_addr dst, struct route *rt) 1703 { 1704 struct sockaddr_in *sin; 1705 1706 sin = (struct sockaddr_in *)&rt->ro_dst; 1707 1708 if (rt->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1709 if (rt->ro_rt != NULL) { 1710 RTFREE(rt->ro_rt); 1711 rt->ro_rt = NULL; 1712 } 1713 sin->sin_family = AF_INET; 1714 sin->sin_len = sizeof *sin; 1715 sin->sin_addr = dst; 1716 rtalloc_ign(rt, RTF_PRCLONING); 1717 } 1718 1719 if (rt->ro_rt == NULL) 1720 return (NULL); 1721 1722 return (ifatoia(rt->ro_rt->rt_ifa)); 1723 } 1724 1725 /* 1726 * Save incoming source route for use in replies, 1727 * to be picked up later by ip_srcroute if the receiver is interested. 1728 */ 1729 void 1730 save_rte(u_char *option, struct in_addr dst) 1731 { 1732 unsigned olen; 1733 1734 olen = option[IPOPT_OLEN]; 1735 #ifdef DIAGNOSTIC 1736 if (ipprintfs) 1737 printf("save_rte: olen %d\n", olen); 1738 #endif 1739 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1740 return; 1741 bcopy(option, ip_srcrt.srcopt, olen); 1742 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1743 ip_srcrt.dst = dst; 1744 } 1745 1746 /* 1747 * Retrieve incoming source route for use in replies, 1748 * in the same form used by setsockopt. 1749 * The first hop is placed before the options, will be removed later. 1750 */ 1751 struct mbuf * 1752 ip_srcroute(void) 1753 { 1754 struct in_addr *p, *q; 1755 struct mbuf *m; 1756 1757 if (ip_nhops == 0) 1758 return (NULL); 1759 m = m_get(MB_DONTWAIT, MT_HEADER); 1760 if (m == NULL) 1761 return (NULL); 1762 1763 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1764 1765 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1766 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1767 OPTSIZ; 1768 #ifdef DIAGNOSTIC 1769 if (ipprintfs) 1770 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1771 #endif 1772 1773 /* 1774 * First save first hop for return route 1775 */ 1776 p = &ip_srcrt.route[ip_nhops - 1]; 1777 *(mtod(m, struct in_addr *)) = *p--; 1778 #ifdef DIAGNOSTIC 1779 if (ipprintfs) 1780 printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1781 #endif 1782 1783 /* 1784 * Copy option fields and padding (nop) to mbuf. 1785 */ 1786 ip_srcrt.nop = IPOPT_NOP; 1787 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1788 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &ip_srcrt.nop, 1789 OPTSIZ); 1790 q = (struct in_addr *)(mtod(m, caddr_t) + 1791 sizeof(struct in_addr) + OPTSIZ); 1792 #undef OPTSIZ 1793 /* 1794 * Record return path as an IP source route, 1795 * reversing the path (pointers are now aligned). 1796 */ 1797 while (p >= ip_srcrt.route) { 1798 #ifdef DIAGNOSTIC 1799 if (ipprintfs) 1800 printf(" %x", ntohl(q->s_addr)); 1801 #endif 1802 *q++ = *p--; 1803 } 1804 /* 1805 * Last hop goes to final destination. 1806 */ 1807 *q = ip_srcrt.dst; 1808 #ifdef DIAGNOSTIC 1809 if (ipprintfs) 1810 printf(" %x\n", ntohl(q->s_addr)); 1811 #endif 1812 return (m); 1813 } 1814 1815 /* 1816 * Strip out IP options. 1817 */ 1818 void 1819 ip_stripoptions(struct mbuf *m) 1820 { 1821 int datalen; 1822 struct ip *ip = mtod(m, struct ip *); 1823 caddr_t opts; 1824 int optlen; 1825 1826 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1827 opts = (caddr_t)(ip + 1); 1828 datalen = m->m_len - (sizeof(struct ip) + optlen); 1829 bcopy(opts + optlen, opts, datalen); 1830 m->m_len -= optlen; 1831 if (m->m_flags & M_PKTHDR) 1832 m->m_pkthdr.len -= optlen; 1833 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1834 } 1835 1836 u_char inetctlerrmap[PRC_NCMDS] = { 1837 0, 0, 0, 0, 1838 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1839 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1840 EMSGSIZE, EHOSTUNREACH, 0, 0, 1841 0, 0, 0, 0, 1842 ENOPROTOOPT, ECONNREFUSED 1843 }; 1844 1845 /* 1846 * Forward a packet. If some error occurs return the sender 1847 * an icmp packet. Note we can't always generate a meaningful 1848 * icmp message because icmp doesn't have a large enough repertoire 1849 * of codes and types. 1850 * 1851 * If not forwarding, just drop the packet. This could be confusing 1852 * if ipforwarding was zero but some routing protocol was advancing 1853 * us as a gateway to somewhere. However, we must let the routing 1854 * protocol deal with that. 1855 * 1856 * The using_srcrt parameter indicates whether the packet is being forwarded 1857 * via a source route. 1858 */ 1859 static void 1860 ip_forward(struct mbuf *m, int using_srcrt, struct sockaddr_in *next_hop) 1861 { 1862 struct ip *ip = mtod(m, struct ip *); 1863 struct sockaddr_in *sin; 1864 struct rtentry *rt; 1865 int error, type = 0, code = 0; 1866 struct mbuf *mcopy; 1867 n_long dest; 1868 struct in_addr pkt_dst; 1869 struct ifnet *destifp; 1870 struct m_hdr tag; 1871 #if defined(IPSEC) || defined(FAST_IPSEC) 1872 struct ifnet dummyifp; 1873 #endif 1874 1875 dest = 0; 1876 /* 1877 * Cache the destination address of the packet; this may be 1878 * changed by use of 'ipfw fwd'. 1879 */ 1880 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 1881 1882 #ifdef DIAGNOSTIC 1883 if (ipprintfs) 1884 printf("forward: src %x dst %x ttl %x\n", 1885 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1886 #endif 1887 1888 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1889 ipstat.ips_cantforward++; 1890 m_freem(m); 1891 return; 1892 } 1893 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1894 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, NULL); 1895 return; 1896 } 1897 1898 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1899 if ((rt = ipforward_rt.ro_rt) == NULL || 1900 pkt_dst.s_addr != sin->sin_addr.s_addr) { 1901 if (ipforward_rt.ro_rt != NULL) { 1902 RTFREE(ipforward_rt.ro_rt); 1903 ipforward_rt.ro_rt = NULL; 1904 } 1905 sin->sin_family = AF_INET; 1906 sin->sin_len = sizeof(*sin); 1907 sin->sin_addr = pkt_dst; 1908 1909 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1910 if (ipforward_rt.ro_rt == NULL) { 1911 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 1912 NULL); 1913 return; 1914 } 1915 rt = ipforward_rt.ro_rt; 1916 } 1917 1918 /* 1919 * Save the IP header and at most 8 bytes of the payload, 1920 * in case we need to generate an ICMP message to the src. 1921 * 1922 * XXX this can be optimized a lot by saving the data in a local 1923 * buffer on the stack (72 bytes at most), and only allocating the 1924 * mbuf if really necessary. The vast majority of the packets 1925 * are forwarded without having to send an ICMP back (either 1926 * because unnecessary, or because rate limited), so we are 1927 * really we are wasting a lot of work here. 1928 * 1929 * We don't use m_copy() because it might return a reference 1930 * to a shared cluster. Both this function and ip_output() 1931 * assume exclusive access to the IP header in `m', so any 1932 * data in a cluster may change before we reach icmp_error(). 1933 */ 1934 MGET(mcopy, MB_DONTWAIT, m->m_type); 1935 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) { 1936 /* 1937 * It's probably ok if the pkthdr dup fails (because 1938 * the deep copy of the tag chain failed), but for now 1939 * be conservative and just discard the copy since 1940 * code below may some day want the tags. 1941 */ 1942 m_free(mcopy); 1943 mcopy = NULL; 1944 } 1945 if (mcopy != NULL) { 1946 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1947 (int)ip->ip_len); 1948 mcopy->m_pkthdr.len = mcopy->m_len; 1949 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1950 } 1951 1952 if (!ipstealth) 1953 ip->ip_ttl -= IPTTLDEC; 1954 1955 /* 1956 * If forwarding packet using same interface that it came in on, 1957 * perhaps should send a redirect to sender to shortcut a hop. 1958 * Only send redirect if source is sending directly to us, 1959 * and if packet was not source routed (or has any options). 1960 * Also, don't send redirect if forwarding using a default route 1961 * or a route modified by a redirect. 1962 */ 1963 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1964 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1965 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1966 ipsendredirects && !using_srcrt && next_hop != NULL) { 1967 u_long src = ntohl(ip->ip_src.s_addr); 1968 1969 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1970 if (RTA(rt) != NULL && 1971 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1972 if (rt->rt_flags & RTF_GATEWAY) 1973 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1974 else 1975 dest = pkt_dst.s_addr; 1976 /* 1977 * Router requirements says to only send 1978 * host redirects. 1979 */ 1980 type = ICMP_REDIRECT; 1981 code = ICMP_REDIRECT_HOST; 1982 #ifdef DIAGNOSTIC 1983 if (ipprintfs) 1984 printf("redirect (%d) to %x\n", code, dest); 1985 #endif 1986 } 1987 } 1988 1989 if (next_hop != NULL) { 1990 /* Pass IPFORWARD info if available */ 1991 tag.mh_type = MT_TAG; 1992 tag.mh_flags = PACKET_TAG_IPFORWARD; 1993 tag.mh_data = (caddr_t)next_hop; 1994 tag.mh_next = m; 1995 m = (struct mbuf *)&tag; 1996 } 1997 1998 error = ip_output(m, NULL, &ipforward_rt, IP_FORWARDING, NULL, NULL); 1999 2000 if (error) 2001 ipstat.ips_cantforward++; 2002 else { 2003 ipstat.ips_forward++; 2004 if (type) 2005 ipstat.ips_redirectsent++; 2006 else { 2007 if (mcopy) { 2008 ipflow_create(&ipforward_rt, mcopy); 2009 m_freem(mcopy); 2010 } 2011 return; 2012 } 2013 } 2014 if (mcopy == NULL) 2015 return; 2016 destifp = NULL; 2017 2018 switch (error) { 2019 2020 case 0: /* forwarded, but need redirect */ 2021 /* type, code set above */ 2022 break; 2023 2024 case ENETUNREACH: /* shouldn't happen, checked above */ 2025 case EHOSTUNREACH: 2026 case ENETDOWN: 2027 case EHOSTDOWN: 2028 default: 2029 type = ICMP_UNREACH; 2030 code = ICMP_UNREACH_HOST; 2031 break; 2032 2033 case EMSGSIZE: 2034 type = ICMP_UNREACH; 2035 code = ICMP_UNREACH_NEEDFRAG; 2036 #ifdef IPSEC 2037 /* 2038 * If the packet is routed over IPsec tunnel, tell the 2039 * originator the tunnel MTU. 2040 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2041 * XXX quickhack!!! 2042 */ 2043 if (ipforward_rt.ro_rt != NULL) { 2044 struct secpolicy *sp = NULL; 2045 int ipsecerror; 2046 int ipsechdr; 2047 struct route *ro; 2048 2049 sp = ipsec4_getpolicybyaddr(mcopy, 2050 IPSEC_DIR_OUTBOUND, 2051 IP_FORWARDING, 2052 &ipsecerror); 2053 2054 if (sp == NULL) 2055 destifp = ipforward_rt.ro_rt->rt_ifp; 2056 else { 2057 /* count IPsec header size */ 2058 ipsechdr = ipsec4_hdrsiz(mcopy, 2059 IPSEC_DIR_OUTBOUND, 2060 NULL); 2061 2062 /* 2063 * find the correct route for outer IPv4 2064 * header, compute tunnel MTU. 2065 * 2066 * XXX BUG ALERT 2067 * The "dummyifp" code relies upon the fact 2068 * that icmp_error() touches only ifp->if_mtu. 2069 */ 2070 /*XXX*/ 2071 destifp = NULL; 2072 if (sp->req != NULL && sp->req->sav != NULL && 2073 sp->req->sav->sah != NULL) { 2074 ro = &sp->req->sav->sah->sa_route; 2075 if (ro->ro_rt != NULL && 2076 ro->ro_rt->rt_ifp != NULL) { 2077 dummyifp.if_mtu = 2078 ro->ro_rt->rt_ifp->if_mtu; 2079 dummyifp.if_mtu -= ipsechdr; 2080 destifp = &dummyifp; 2081 } 2082 } 2083 2084 key_freesp(sp); 2085 } 2086 } 2087 #elif FAST_IPSEC 2088 /* 2089 * If the packet is routed over IPsec tunnel, tell the 2090 * originator the tunnel MTU. 2091 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2092 * XXX quickhack!!! 2093 */ 2094 if (ipforward_rt.ro_rt != NULL) { 2095 struct secpolicy *sp = NULL; 2096 int ipsecerror; 2097 int ipsechdr; 2098 struct route *ro; 2099 2100 sp = ipsec_getpolicybyaddr(mcopy, 2101 IPSEC_DIR_OUTBOUND, 2102 IP_FORWARDING, 2103 &ipsecerror); 2104 2105 if (sp == NULL) 2106 destifp = ipforward_rt.ro_rt->rt_ifp; 2107 else { 2108 /* count IPsec header size */ 2109 ipsechdr = ipsec4_hdrsiz(mcopy, 2110 IPSEC_DIR_OUTBOUND, 2111 NULL); 2112 2113 /* 2114 * find the correct route for outer IPv4 2115 * header, compute tunnel MTU. 2116 * 2117 * XXX BUG ALERT 2118 * The "dummyifp" code relies upon the fact 2119 * that icmp_error() touches only ifp->if_mtu. 2120 */ 2121 /*XXX*/ 2122 destifp = NULL; 2123 if (sp->req != NULL && 2124 sp->req->sav != NULL && 2125 sp->req->sav->sah != NULL) { 2126 ro = &sp->req->sav->sah->sa_route; 2127 if (ro->ro_rt != NULL && 2128 ro->ro_rt->rt_ifp != NULL) { 2129 dummyifp.if_mtu = 2130 ro->ro_rt->rt_ifp->if_mtu; 2131 dummyifp.if_mtu -= ipsechdr; 2132 destifp = &dummyifp; 2133 } 2134 } 2135 2136 KEY_FREESP(&sp); 2137 } 2138 } 2139 #else /* !IPSEC && !FAST_IPSEC */ 2140 if (ipforward_rt.ro_rt != NULL) 2141 destifp = ipforward_rt.ro_rt->rt_ifp; 2142 #endif /*IPSEC*/ 2143 ipstat.ips_cantfrag++; 2144 break; 2145 2146 case ENOBUFS: 2147 /* 2148 * A router should not generate ICMP_SOURCEQUENCH as 2149 * required in RFC1812 Requirements for IP Version 4 Routers. 2150 * Source quench could be a big problem under DoS attacks, 2151 * or if the underlying interface is rate-limited. 2152 * Those who need source quench packets may re-enable them 2153 * via the net.inet.ip.sendsourcequench sysctl. 2154 */ 2155 if (!ip_sendsourcequench) { 2156 m_freem(mcopy); 2157 return; 2158 } else { 2159 type = ICMP_SOURCEQUENCH; 2160 code = 0; 2161 } 2162 break; 2163 2164 case EACCES: /* ipfw denied packet */ 2165 m_freem(mcopy); 2166 return; 2167 } 2168 icmp_error(mcopy, type, code, dest, destifp); 2169 } 2170 2171 void 2172 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2173 struct mbuf *m) 2174 { 2175 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2176 struct timeval tv; 2177 2178 microtime(&tv); 2179 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2180 SCM_TIMESTAMP, SOL_SOCKET); 2181 if (*mp) 2182 mp = &(*mp)->m_next; 2183 } 2184 if (inp->inp_flags & INP_RECVDSTADDR) { 2185 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2186 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2187 if (*mp) 2188 mp = &(*mp)->m_next; 2189 } 2190 #ifdef notyet 2191 /* XXX 2192 * Moving these out of udp_input() made them even more broken 2193 * than they already were. 2194 */ 2195 /* options were tossed already */ 2196 if (inp->inp_flags & INP_RECVOPTS) { 2197 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2198 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2199 if (*mp) 2200 mp = &(*mp)->m_next; 2201 } 2202 /* ip_srcroute doesn't do what we want here, need to fix */ 2203 if (inp->inp_flags & INP_RECVRETOPTS) { 2204 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2205 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2206 if (*mp) 2207 mp = &(*mp)->m_next; 2208 } 2209 #endif 2210 if (inp->inp_flags & INP_RECVIF) { 2211 struct ifnet *ifp; 2212 struct sdlbuf { 2213 struct sockaddr_dl sdl; 2214 u_char pad[32]; 2215 } sdlbuf; 2216 struct sockaddr_dl *sdp; 2217 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2218 2219 if (((ifp = m->m_pkthdr.rcvif)) && 2220 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2221 sdp = (struct sockaddr_dl *) 2222 ifnet_addrs[ifp->if_index - 1]->ifa_addr; 2223 /* 2224 * Change our mind and don't try copy. 2225 */ 2226 if ((sdp->sdl_family != AF_LINK) || 2227 (sdp->sdl_len > sizeof(sdlbuf))) { 2228 goto makedummy; 2229 } 2230 bcopy(sdp, sdl2, sdp->sdl_len); 2231 } else { 2232 makedummy: 2233 sdl2->sdl_len = 2234 offsetof(struct sockaddr_dl, sdl_data[0]); 2235 sdl2->sdl_family = AF_LINK; 2236 sdl2->sdl_index = 0; 2237 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2238 } 2239 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2240 IP_RECVIF, IPPROTO_IP); 2241 if (*mp) 2242 mp = &(*mp)->m_next; 2243 } 2244 } 2245 2246 /* 2247 * XXX these routines are called from the upper part of the kernel. 2248 * 2249 * They could also be moved to ip_mroute.c, since all the RSVP 2250 * handling is done there already. 2251 */ 2252 int 2253 ip_rsvp_init(struct socket *so) 2254 { 2255 if (so->so_type != SOCK_RAW || 2256 so->so_proto->pr_protocol != IPPROTO_RSVP) 2257 return EOPNOTSUPP; 2258 2259 if (ip_rsvpd != NULL) 2260 return EADDRINUSE; 2261 2262 ip_rsvpd = so; 2263 /* 2264 * This may seem silly, but we need to be sure we don't over-increment 2265 * the RSVP counter, in case something slips up. 2266 */ 2267 if (!ip_rsvp_on) { 2268 ip_rsvp_on = 1; 2269 rsvp_on++; 2270 } 2271 2272 return 0; 2273 } 2274 2275 int 2276 ip_rsvp_done(void) 2277 { 2278 ip_rsvpd = NULL; 2279 /* 2280 * This may seem silly, but we need to be sure we don't over-decrement 2281 * the RSVP counter, in case something slips up. 2282 */ 2283 if (ip_rsvp_on) { 2284 ip_rsvp_on = 0; 2285 rsvp_on--; 2286 } 2287 return 0; 2288 } 2289 2290 void 2291 rsvp_input(struct mbuf *m, ...) /* XXX must fixup manually */ 2292 { 2293 int off, proto; 2294 __va_list ap; 2295 2296 __va_start(ap, m); 2297 off = __va_arg(ap, int); 2298 proto = __va_arg(ap, int); 2299 __va_end(ap); 2300 2301 if (rsvp_input_p) { /* call the real one if loaded */ 2302 rsvp_input_p(m, off, proto); 2303 return; 2304 } 2305 2306 /* Can still get packets with rsvp_on = 0 if there is a local member 2307 * of the group to which the RSVP packet is addressed. But in this 2308 * case we want to throw the packet away. 2309 */ 2310 2311 if (!rsvp_on) { 2312 m_freem(m); 2313 return; 2314 } 2315 2316 if (ip_rsvpd != NULL) { 2317 rip_input(m, off, proto); 2318 return; 2319 } 2320 /* Drop the packet */ 2321 m_freem(m); 2322 } 2323