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 1.67 2007/05/23 08:57:09 dillon 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 97 #include <machine/stdarg.h> 98 99 #include <net/if.h> 100 #include <net/if_types.h> 101 #include <net/if_var.h> 102 #include <net/if_dl.h> 103 #include <net/pfil.h> 104 #include <net/route.h> 105 #include <net/netisr.h> 106 #include <net/intrq.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> 115 116 #include <sys/thread2.h> 117 #include <sys/msgport2.h> 118 #include <net/netmsg2.h> 119 120 #include <sys/socketvar.h> 121 122 #include <net/ipfw/ip_fw.h> 123 #include <net/dummynet/ip_dummynet.h> 124 125 #ifdef IPSEC 126 #include <netinet6/ipsec.h> 127 #include <netproto/key/key.h> 128 #endif 129 130 #ifdef FAST_IPSEC 131 #include <netproto/ipsec/ipsec.h> 132 #include <netproto/ipsec/key.h> 133 #endif 134 135 int rsvp_on = 0; 136 static int ip_rsvp_on; 137 struct socket *ip_rsvpd; 138 139 int ipforwarding = 0; 140 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 141 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 142 143 static int ipsendredirects = 1; /* XXX */ 144 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 145 &ipsendredirects, 0, "Enable sending IP redirects"); 146 147 int ip_defttl = IPDEFTTL; 148 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 149 &ip_defttl, 0, "Maximum TTL on IP packets"); 150 151 static int ip_dosourceroute = 0; 152 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 153 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 154 155 static int ip_acceptsourceroute = 0; 156 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 157 CTLFLAG_RW, &ip_acceptsourceroute, 0, 158 "Enable accepting source routed IP packets"); 159 160 static int ip_keepfaith = 0; 161 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 162 &ip_keepfaith, 0, 163 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 164 165 static int nipq = 0; /* total # of reass queues */ 166 static int maxnipq; 167 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 168 &maxnipq, 0, 169 "Maximum number of IPv4 fragment reassembly queue entries"); 170 171 static int maxfragsperpacket; 172 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 173 &maxfragsperpacket, 0, 174 "Maximum number of IPv4 fragments allowed per packet"); 175 176 static int ip_sendsourcequench = 0; 177 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 178 &ip_sendsourcequench, 0, 179 "Enable the transmission of source quench packets"); 180 181 int ip_do_randomid = 0; 182 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 183 &ip_do_randomid, 0, 184 "Assign random ip_id values"); 185 /* 186 * XXX - Setting ip_checkinterface mostly implements the receive side of 187 * the Strong ES model described in RFC 1122, but since the routing table 188 * and transmit implementation do not implement the Strong ES model, 189 * setting this to 1 results in an odd hybrid. 190 * 191 * XXX - ip_checkinterface currently must be disabled if you use ipnat 192 * to translate the destination address to another local interface. 193 * 194 * XXX - ip_checkinterface must be disabled if you add IP aliases 195 * to the loopback interface instead of the interface where the 196 * packets for those addresses are received. 197 */ 198 static int ip_checkinterface = 0; 199 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 200 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 201 202 #ifdef DIAGNOSTIC 203 static int ipprintfs = 0; 204 #endif 205 206 static struct ifqueue ipintrq; 207 static int ipqmaxlen = IFQ_MAXLEN; 208 209 extern struct domain inetdomain; 210 extern struct protosw inetsw[]; 211 u_char ip_protox[IPPROTO_MAX]; 212 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 213 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 214 u_long in_ifaddrhmask; /* mask for hash table */ 215 216 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 217 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 218 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 219 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 220 221 struct ip_stats ipstats_percpu[MAXCPU]; 222 #ifdef SMP 223 static int 224 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 225 { 226 int cpu, error = 0; 227 228 for (cpu = 0; cpu < ncpus; ++cpu) { 229 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu], 230 sizeof(struct ip_stats)))) 231 break; 232 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu], 233 sizeof(struct ip_stats)))) 234 break; 235 } 236 237 return (error); 238 } 239 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 240 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 241 #else 242 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 243 &ipstat, ip_stats, "IP statistics"); 244 #endif 245 246 /* Packet reassembly stuff */ 247 #define IPREASS_NHASH_LOG2 6 248 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 249 #define IPREASS_HMASK (IPREASS_NHASH - 1) 250 #define IPREASS_HASH(x,y) \ 251 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 252 253 static struct ipq ipq[IPREASS_NHASH]; 254 const int ipintrq_present = 1; 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 267 268 269 /* Firewall hooks */ 270 ip_fw_chk_t *ip_fw_chk_ptr; 271 int fw_enable = 1; 272 int fw_one_pass = 1; 273 274 /* Dummynet hooks */ 275 ip_dn_io_t *ip_dn_io_ptr; 276 277 struct pfil_head inet_pfil_hook; 278 279 /* 280 * XXX this is ugly -- the following two global variables are 281 * used to store packet state while it travels through the stack. 282 * Note that the code even makes assumptions on the size and 283 * alignment of fields inside struct ip_srcrt so e.g. adding some 284 * fields will break the code. This needs to be fixed. 285 * 286 * We need to save the IP options in case a protocol wants to respond 287 * to an incoming packet over the same route if the packet got here 288 * using IP source routing. This allows connection establishment and 289 * maintenance when the remote end is on a network that is not known 290 * to us. 291 */ 292 static int ip_nhops = 0; 293 294 static struct ip_srcrt { 295 struct in_addr dst; /* final destination */ 296 char nop; /* one NOP to align */ 297 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 298 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 299 } ip_srcrt; 300 301 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 302 static struct malloc_pipe ipq_mpipe; 303 304 static void save_rte (u_char *, struct in_addr); 305 static int ip_dooptions (struct mbuf *m, int, 306 struct sockaddr_in *next_hop); 307 static void ip_forward (struct mbuf *m, boolean_t using_srcrt, 308 struct sockaddr_in *next_hop); 309 static void ip_freef (struct ipq *); 310 static void ip_input_handler (struct netmsg *); 311 static struct mbuf *ip_reass (struct mbuf *, struct ipq *, 312 struct ipq *, u_int32_t *); 313 314 /* 315 * IP initialization: fill in IP protocol switch table. 316 * All protocols not implemented in kernel go to raw IP protocol handler. 317 */ 318 void 319 ip_init(void) 320 { 321 struct protosw *pr; 322 int i; 323 #ifdef SMP 324 int cpu; 325 #endif 326 327 /* 328 * Make sure we can handle a reasonable number of fragments but 329 * cap it at 4000 (XXX). 330 */ 331 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 332 IFQ_MAXLEN, 4000, 0, NULL); 333 TAILQ_INIT(&in_ifaddrhead); 334 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 335 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 336 if (pr == NULL) 337 panic("ip_init"); 338 for (i = 0; i < IPPROTO_MAX; i++) 339 ip_protox[i] = pr - inetsw; 340 for (pr = inetdomain.dom_protosw; 341 pr < inetdomain.dom_protoswNPROTOSW; pr++) 342 if (pr->pr_domain->dom_family == PF_INET && 343 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 344 ip_protox[pr->pr_protocol] = pr - inetsw; 345 346 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 347 inet_pfil_hook.ph_af = AF_INET; 348 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) { 349 kprintf("%s: WARNING: unable to register pfil hook, " 350 "error %d\n", __func__, i); 351 } 352 353 for (i = 0; i < IPREASS_NHASH; i++) 354 ipq[i].next = ipq[i].prev = &ipq[i]; 355 356 maxnipq = nmbclusters / 32; 357 maxfragsperpacket = 16; 358 359 ip_id = time_second & 0xffff; 360 ipintrq.ifq_maxlen = ipqmaxlen; 361 362 /* 363 * Initialize IP statistics counters for each CPU. 364 * 365 */ 366 #ifdef SMP 367 for (cpu = 0; cpu < ncpus; ++cpu) { 368 bzero(&ipstats_percpu[cpu], sizeof(struct ip_stats)); 369 } 370 #else 371 bzero(&ipstat, sizeof(struct ip_stats)); 372 #endif 373 374 netisr_register(NETISR_IP, ip_mport, ip_input_handler); 375 } 376 377 /* 378 * XXX watch out this one. It is perhaps used as a cache for 379 * the most recently used route ? it is cleared in in_addroute() 380 * when a new route is successfully created. 381 */ 382 struct route ipforward_rt[MAXCPU]; 383 384 /* Do transport protocol processing. */ 385 static void 386 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip, 387 struct sockaddr_in *nexthop) 388 { 389 /* 390 * Switch out to protocol's input routine. 391 */ 392 if (nexthop && ip->ip_p == IPPROTO_TCP) { 393 /* TCP needs IPFORWARD info if available */ 394 struct m_hdr tag; 395 396 tag.mh_type = MT_TAG; 397 tag.mh_flags = PACKET_TAG_IPFORWARD; 398 tag.mh_data = (caddr_t)nexthop; 399 tag.mh_next = m; 400 401 (*inetsw[ip_protox[ip->ip_p]].pr_input) 402 ((struct mbuf *)&tag, hlen, ip->ip_p); 403 } else { 404 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, ip->ip_p); 405 } 406 } 407 408 struct netmsg_transport_packet { 409 struct netmsg nm_netmsg; 410 struct mbuf *nm_mbuf; 411 int nm_hlen; 412 boolean_t nm_hasnexthop; 413 struct sockaddr_in nm_nexthop; 414 }; 415 416 static void 417 transport_processing_handler(netmsg_t netmsg) 418 { 419 struct netmsg_transport_packet *msg = (void *)netmsg; 420 struct sockaddr_in *nexthop; 421 struct ip *ip; 422 423 ip = mtod(msg->nm_mbuf, struct ip *); 424 nexthop = msg->nm_hasnexthop ? &msg->nm_nexthop : NULL; 425 transport_processing_oncpu(msg->nm_mbuf, msg->nm_hlen, ip, nexthop); 426 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0); 427 } 428 429 static void 430 ip_input_handler(struct netmsg *msg0) 431 { 432 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet; 433 434 ip_input(m); 435 /* msg0 was embedded in the mbuf, do not reply! */ 436 } 437 438 /* 439 * IP input routine. Checksum and byte swap header. If fragmented 440 * try to reassemble. Process options. Pass to next level. 441 */ 442 void 443 ip_input(struct mbuf *m) 444 { 445 struct ip *ip; 446 struct ipq *fp; 447 struct in_ifaddr *ia = NULL; 448 struct ifaddr *ifa; 449 int i, hlen, checkif; 450 u_short sum; 451 struct in_addr pkt_dst; 452 u_int32_t divert_info = 0; /* packet divert/tee info */ 453 struct ip_fw_args args; 454 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 455 boolean_t needredispatch = FALSE; 456 struct in_addr odst; /* original dst address(NAT) */ 457 #if defined(FAST_IPSEC) || defined(IPDIVERT) 458 struct m_tag *mtag; 459 #endif 460 #ifdef FAST_IPSEC 461 struct tdb_ident *tdbi; 462 struct secpolicy *sp; 463 int error; 464 #endif 465 466 args.eh = NULL; 467 args.oif = NULL; 468 args.rule = NULL; 469 args.next_hop = NULL; 470 471 /* Grab info from MT_TAG mbufs prepended to the chain. */ 472 while (m != NULL && m->m_type == MT_TAG) { 473 switch(m->_m_tag_id) { 474 case PACKET_TAG_DUMMYNET: 475 args.rule = ((struct dn_pkt *)m)->rule; 476 break; 477 case PACKET_TAG_IPFORWARD: 478 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 479 break; 480 default: 481 kprintf("ip_input: unrecognised MT_TAG tag %d\n", 482 m->_m_tag_id); 483 break; 484 } 485 m = m->m_next; 486 } 487 KASSERT(m != NULL && (m->m_flags & M_PKTHDR), ("ip_input: no HDR")); 488 489 if (args.rule != NULL) { /* dummynet already filtered us */ 490 ip = mtod(m, struct ip *); 491 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 492 goto iphack; 493 } 494 495 ipstat.ips_total++; 496 497 /* length checks already done in ip_demux() */ 498 KASSERT(m->m_len >= sizeof(ip), ("IP header not in one mbuf")); 499 500 ip = mtod(m, struct ip *); 501 502 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 503 ipstat.ips_badvers++; 504 goto bad; 505 } 506 507 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 508 /* length checks already done in ip_demux() */ 509 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 510 KASSERT(m->m_len >= hlen, ("packet shorter than IP header length")); 511 512 /* 127/8 must not appear on wire - RFC1122 */ 513 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 514 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 515 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 516 ipstat.ips_badaddr++; 517 goto bad; 518 } 519 } 520 521 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 522 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 523 } else { 524 if (hlen == sizeof(struct ip)) { 525 sum = in_cksum_hdr(ip); 526 } else { 527 sum = in_cksum(m, hlen); 528 } 529 } 530 if (sum != 0) { 531 ipstat.ips_badsum++; 532 goto bad; 533 } 534 535 #ifdef ALTQ 536 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 537 /* packet is dropped by traffic conditioner */ 538 return; 539 } 540 #endif 541 /* 542 * Convert fields to host representation. 543 */ 544 ip->ip_len = ntohs(ip->ip_len); 545 if (ip->ip_len < hlen) { 546 ipstat.ips_badlen++; 547 goto bad; 548 } 549 ip->ip_off = ntohs(ip->ip_off); 550 551 /* 552 * Check that the amount of data in the buffers 553 * is as at least much as the IP header would have us expect. 554 * Trim mbufs if longer than we expect. 555 * Drop packet if shorter than we expect. 556 */ 557 if (m->m_pkthdr.len < ip->ip_len) { 558 ipstat.ips_tooshort++; 559 goto bad; 560 } 561 if (m->m_pkthdr.len > ip->ip_len) { 562 if (m->m_len == m->m_pkthdr.len) { 563 m->m_len = ip->ip_len; 564 m->m_pkthdr.len = ip->ip_len; 565 } else 566 m_adj(m, ip->ip_len - m->m_pkthdr.len); 567 } 568 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 569 /* 570 * Bypass packet filtering for packets from a tunnel (gif). 571 */ 572 if (ipsec_gethist(m, NULL)) 573 goto pass; 574 #endif 575 576 /* 577 * IpHack's section. 578 * Right now when no processing on packet has done 579 * and it is still fresh out of network we do our black 580 * deals with it. 581 * - Firewall: deny/allow/divert 582 * - Xlate: translate packet's addr/port (NAT). 583 * - Pipe: pass pkt through dummynet. 584 * - Wrap: fake packet's addr/port <unimpl.> 585 * - Encapsulate: put it in another IP and send out. <unimp.> 586 */ 587 588 iphack: 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 if (pfil_has_hooks(&inet_pfil_hook)) { 598 odst = ip->ip_dst; 599 if (pfil_run_hooks(&inet_pfil_hook, &m, 600 m->m_pkthdr.rcvif, PFIL_IN)) { 601 return; 602 } 603 if (m == NULL) /* consumed by filter */ 604 return; 605 ip = mtod(m, struct ip *); 606 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 607 } 608 609 if (fw_enable && IPFW_LOADED) { 610 /* 611 * If we've been forwarded from the output side, then 612 * skip the firewall a second time 613 */ 614 if (args.next_hop != NULL) 615 goto ours; 616 617 args.m = m; 618 i = ip_fw_chk_ptr(&args); 619 m = args.m; 620 621 if ((i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 622 if (m != NULL) 623 m_freem(m); 624 return; 625 } 626 ip = mtod(m, struct ip *); /* just in case m changed */ 627 if (i == 0 && args.next_hop == NULL) /* common case */ 628 goto pass; 629 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG)) { 630 /* Send packet to the appropriate pipe */ 631 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 632 return; 633 } 634 #ifdef IPDIVERT 635 if (i != 0 && !(i & IP_FW_PORT_DYNT_FLAG)) { 636 /* Divert or tee packet */ 637 divert_info = i; 638 goto ours; 639 } 640 #endif 641 if (i == 0 && args.next_hop != NULL) 642 goto pass; 643 /* 644 * if we get here, the packet must be dropped 645 */ 646 m_freem(m); 647 return; 648 } 649 pass: 650 651 /* 652 * Process options and, if not destined for us, 653 * ship it on. ip_dooptions returns 1 when an 654 * error was detected (causing an icmp message 655 * to be sent and the original packet to be freed). 656 */ 657 ip_nhops = 0; /* for source routed packets */ 658 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, args.next_hop)) 659 return; 660 661 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 662 * matter if it is destined to another node, or whether it is 663 * a multicast one, RSVP wants it! and prevents it from being forwarded 664 * anywhere else. Also checks if the rsvp daemon is running before 665 * grabbing the packet. 666 */ 667 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 668 goto ours; 669 670 /* 671 * Check our list of addresses, to see if the packet is for us. 672 * If we don't have any addresses, assume any unicast packet 673 * we receive might be for us (and let the upper layers deal 674 * with it). 675 */ 676 if (TAILQ_EMPTY(&in_ifaddrhead) && !(m->m_flags & (M_MCAST | M_BCAST))) 677 goto ours; 678 679 /* 680 * Cache the destination address of the packet; this may be 681 * changed by use of 'ipfw fwd'. 682 */ 683 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 684 685 /* 686 * Enable a consistency check between the destination address 687 * and the arrival interface for a unicast packet (the RFC 1122 688 * strong ES model) if IP forwarding is disabled and the packet 689 * is not locally generated and the packet is not subject to 690 * 'ipfw fwd'. 691 * 692 * XXX - Checking also should be disabled if the destination 693 * address is ipnat'ed to a different interface. 694 * 695 * XXX - Checking is incompatible with IP aliases added 696 * to the loopback interface instead of the interface where 697 * the packets are received. 698 */ 699 checkif = ip_checkinterface && 700 !ipforwarding && 701 m->m_pkthdr.rcvif != NULL && 702 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 703 (args.next_hop == NULL); 704 705 /* 706 * Check for exact addresses in the hash bucket. 707 */ 708 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 709 /* 710 * If the address matches, verify that the packet 711 * arrived via the correct interface if checking is 712 * enabled. 713 */ 714 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 715 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 716 goto ours; 717 } 718 /* 719 * Check for broadcast addresses. 720 * 721 * Only accept broadcast packets that arrive via the matching 722 * interface. Reception of forwarded directed broadcasts would 723 * be handled via ip_forward() and ether_output() with the loopback 724 * into the stack for SIMPLEX interfaces handled by ether_output(). 725 */ 726 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 727 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 728 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 729 continue; 730 if (ifa->ifa_addr->sa_family != AF_INET) 731 continue; 732 ia = ifatoia(ifa); 733 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 734 pkt_dst.s_addr) 735 goto ours; 736 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 737 goto ours; 738 #ifdef BOOTP_COMPAT 739 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 740 goto ours; 741 #endif 742 } 743 } 744 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 745 struct in_multi *inm; 746 747 if (ip_mrouter != NULL) { 748 /* 749 * If we are acting as a multicast router, all 750 * incoming multicast packets are passed to the 751 * kernel-level multicast forwarding function. 752 * The packet is returned (relatively) intact; if 753 * ip_mforward() returns a non-zero value, the packet 754 * must be discarded, else it may be accepted below. 755 */ 756 if (ip_mforward != NULL && 757 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 758 ipstat.ips_cantforward++; 759 m_freem(m); 760 return; 761 } 762 763 /* 764 * The process-level routing daemon needs to receive 765 * all multicast IGMP packets, whether or not this 766 * host belongs to their destination groups. 767 */ 768 if (ip->ip_p == IPPROTO_IGMP) 769 goto ours; 770 ipstat.ips_forward++; 771 } 772 /* 773 * See if we belong to the destination multicast group on the 774 * arrival interface. 775 */ 776 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 777 if (inm == NULL) { 778 ipstat.ips_notmember++; 779 m_freem(m); 780 return; 781 } 782 goto ours; 783 } 784 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 785 goto ours; 786 if (ip->ip_dst.s_addr == INADDR_ANY) 787 goto ours; 788 789 /* 790 * FAITH(Firewall Aided Internet Translator) 791 */ 792 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 793 if (ip_keepfaith) { 794 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 795 goto ours; 796 } 797 m_freem(m); 798 return; 799 } 800 801 /* 802 * Not for us; forward if possible and desirable. 803 */ 804 if (!ipforwarding) { 805 ipstat.ips_cantforward++; 806 m_freem(m); 807 } else { 808 #ifdef IPSEC 809 /* 810 * Enforce inbound IPsec SPD. 811 */ 812 if (ipsec4_in_reject(m, NULL)) { 813 ipsecstat.in_polvio++; 814 goto bad; 815 } 816 #endif 817 #ifdef FAST_IPSEC 818 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 819 crit_enter(); 820 if (mtag != NULL) { 821 tdbi = (struct tdb_ident *)m_tag_data(mtag); 822 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 823 } else { 824 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 825 IP_FORWARDING, &error); 826 } 827 if (sp == NULL) { /* NB: can happen if error */ 828 crit_exit(); 829 /*XXX error stat???*/ 830 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 831 goto bad; 832 } 833 834 /* 835 * Check security policy against packet attributes. 836 */ 837 error = ipsec_in_reject(sp, m); 838 KEY_FREESP(&sp); 839 crit_exit(); 840 if (error) { 841 ipstat.ips_cantforward++; 842 goto bad; 843 } 844 #endif 845 ip_forward(m, using_srcrt, args.next_hop); 846 } 847 return; 848 849 ours: 850 851 /* 852 * IPSTEALTH: Process non-routing options only 853 * if the packet is destined for us. 854 */ 855 if (ipstealth && 856 hlen > sizeof(struct ip) && 857 ip_dooptions(m, 1, args.next_hop)) 858 return; 859 860 /* Count the packet in the ip address stats */ 861 if (ia != NULL) { 862 ia->ia_ifa.if_ipackets++; 863 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 864 } 865 866 /* 867 * If offset or IP_MF are set, must reassemble. 868 * Otherwise, nothing need be done. 869 * (We could look in the reassembly queue to see 870 * if the packet was previously fragmented, 871 * but it's not worth the time; just let them time out.) 872 */ 873 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 874 875 /* If maxnipq is 0, never accept fragments. */ 876 if (maxnipq == 0) { 877 ipstat.ips_fragments++; 878 ipstat.ips_fragdropped++; 879 goto bad; 880 } 881 882 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 883 /* 884 * Look for queue of fragments 885 * of this datagram. 886 */ 887 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 888 if (ip->ip_id == fp->ipq_id && 889 ip->ip_src.s_addr == fp->ipq_src.s_addr && 890 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 891 ip->ip_p == fp->ipq_p) 892 goto found; 893 894 fp = NULL; 895 896 /* 897 * Enforce upper bound on number of fragmented packets 898 * for which we attempt reassembly; 899 * If maxnipq is -1, accept all fragments without limitation. 900 */ 901 if ((nipq > maxnipq) && (maxnipq > 0)) { 902 /* 903 * drop something from the tail of the current queue 904 * before proceeding further 905 */ 906 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 907 for (i = 0; i < IPREASS_NHASH; i++) { 908 if (ipq[i].prev != &ipq[i]) { 909 ipstat.ips_fragtimeout += 910 ipq[i].prev->ipq_nfrags; 911 ip_freef(ipq[i].prev); 912 break; 913 } 914 } 915 } else { 916 ipstat.ips_fragtimeout += 917 ipq[sum].prev->ipq_nfrags; 918 ip_freef(ipq[sum].prev); 919 } 920 } 921 found: 922 /* 923 * Adjust ip_len to not reflect header, 924 * convert offset of this to bytes. 925 */ 926 ip->ip_len -= hlen; 927 if (ip->ip_off & IP_MF) { 928 /* 929 * Make sure that fragments have a data length 930 * that's a non-zero multiple of 8 bytes. 931 */ 932 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 933 ipstat.ips_toosmall++; /* XXX */ 934 goto bad; 935 } 936 m->m_flags |= M_FRAG; 937 } else 938 m->m_flags &= ~M_FRAG; 939 ip->ip_off <<= 3; 940 941 /* 942 * Attempt reassembly; if it succeeds, proceed. 943 * ip_reass() will return a different mbuf, and update 944 * the divert info in divert_info. 945 */ 946 ipstat.ips_fragments++; 947 m->m_pkthdr.header = ip; 948 m = ip_reass(m, fp, &ipq[sum], &divert_info); 949 if (m == NULL) 950 return; 951 ipstat.ips_reassembled++; 952 needredispatch = TRUE; 953 ip = mtod(m, struct ip *); 954 /* Get the header length of the reassembled packet */ 955 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 956 #ifdef IPDIVERT 957 /* Restore original checksum before diverting packet */ 958 if (divert_info != 0) { 959 ip->ip_len += hlen; 960 ip->ip_len = htons(ip->ip_len); 961 ip->ip_off = htons(ip->ip_off); 962 ip->ip_sum = 0; 963 if (hlen == sizeof(struct ip)) 964 ip->ip_sum = in_cksum_hdr(ip); 965 else 966 ip->ip_sum = in_cksum(m, hlen); 967 ip->ip_off = ntohs(ip->ip_off); 968 ip->ip_len = ntohs(ip->ip_len); 969 ip->ip_len -= hlen; 970 } 971 #endif 972 } else { 973 ip->ip_len -= hlen; 974 } 975 976 #ifdef IPDIVERT 977 /* 978 * Divert or tee packet to the divert protocol if required. 979 */ 980 if (divert_info != 0) { 981 struct mbuf *clone = NULL; 982 983 /* Clone packet if we're doing a 'tee' */ 984 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 985 clone = m_dup(m, MB_DONTWAIT); 986 987 /* Restore packet header fields to original values */ 988 ip->ip_len += hlen; 989 ip->ip_len = htons(ip->ip_len); 990 ip->ip_off = htons(ip->ip_off); 991 992 /* Deliver packet to divert input routine */ 993 divert_packet(m, 1, divert_info & 0xffff); 994 ipstat.ips_delivered++; 995 996 /* If 'tee', continue with original packet */ 997 if (clone == NULL) 998 return; 999 m = clone; 1000 ip = mtod(m, struct ip *); 1001 ip->ip_len += hlen; 1002 /* 1003 * Jump backwards to complete processing of the 1004 * packet. But first clear divert_info to avoid 1005 * entering this block again. 1006 * We do not need to clear args.divert_rule 1007 * or args.next_hop as they will not be used. 1008 * 1009 * XXX Better safe than sorry, remove the DIVERT tag. 1010 */ 1011 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 1012 if (mtag != NULL) 1013 m_tag_delete(m, mtag); 1014 1015 divert_info = 0; 1016 goto pass; 1017 } 1018 #endif 1019 1020 #ifdef IPSEC 1021 /* 1022 * enforce IPsec policy checking if we are seeing last header. 1023 * note that we do not visit this with protocols with pcb layer 1024 * code - like udp/tcp/raw ip. 1025 */ 1026 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 1027 ipsec4_in_reject(m, NULL)) { 1028 ipsecstat.in_polvio++; 1029 goto bad; 1030 } 1031 #endif 1032 #if FAST_IPSEC 1033 /* 1034 * enforce IPsec policy checking if we are seeing last header. 1035 * note that we do not visit this with protocols with pcb layer 1036 * code - like udp/tcp/raw ip. 1037 */ 1038 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 1039 /* 1040 * Check if the packet has already had IPsec processing 1041 * done. If so, then just pass it along. This tag gets 1042 * set during AH, ESP, etc. input handling, before the 1043 * packet is returned to the ip input queue for delivery. 1044 */ 1045 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 1046 crit_enter(); 1047 if (mtag != NULL) { 1048 tdbi = (struct tdb_ident *)m_tag_data(mtag); 1049 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 1050 } else { 1051 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 1052 IP_FORWARDING, &error); 1053 } 1054 if (sp != NULL) { 1055 /* 1056 * Check security policy against packet attributes. 1057 */ 1058 error = ipsec_in_reject(sp, m); 1059 KEY_FREESP(&sp); 1060 } else { 1061 /* XXX error stat??? */ 1062 error = EINVAL; 1063 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 1064 goto bad; 1065 } 1066 crit_exit(); 1067 if (error) 1068 goto bad; 1069 } 1070 #endif /* FAST_IPSEC */ 1071 1072 ipstat.ips_delivered++; 1073 if (needredispatch) { 1074 struct netmsg_transport_packet *msg; 1075 lwkt_port_t port; 1076 1077 ip->ip_off = htons(ip->ip_off); 1078 ip->ip_len = htons(ip->ip_len); 1079 port = ip_mport(&m); 1080 if (port == NULL) 1081 return; 1082 1083 msg = kmalloc(sizeof(struct netmsg_transport_packet), M_LWKTMSG, 1084 M_INTWAIT | M_NULLOK); 1085 if (msg == NULL) 1086 goto bad; 1087 1088 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0, 1089 transport_processing_handler); 1090 msg->nm_hlen = hlen; 1091 msg->nm_hasnexthop = (args.next_hop != NULL); 1092 if (msg->nm_hasnexthop) 1093 msg->nm_nexthop = *args.next_hop; /* structure copy */ 1094 1095 msg->nm_mbuf = m; 1096 ip = mtod(m, struct ip *); 1097 ip->ip_len = ntohs(ip->ip_len); 1098 ip->ip_off = ntohs(ip->ip_off); 1099 lwkt_sendmsg(port, &msg->nm_netmsg.nm_lmsg); 1100 } else { 1101 transport_processing_oncpu(m, hlen, ip, args.next_hop); 1102 } 1103 return; 1104 1105 bad: 1106 m_freem(m); 1107 } 1108 1109 /* 1110 * Take incoming datagram fragment and try to reassemble it into 1111 * whole datagram. If a chain for reassembly of this datagram already 1112 * exists, then it is given as fp; otherwise have to make a chain. 1113 * 1114 * When IPDIVERT enabled, keep additional state with each packet that 1115 * tells us if we need to divert or tee the packet we're building. 1116 * In particular, *divinfo includes the port and TEE flag. 1117 */ 1118 1119 static struct mbuf * 1120 ip_reass(struct mbuf *m, struct ipq *fp, struct ipq *where, 1121 u_int32_t *divinfo) 1122 { 1123 struct ip *ip = mtod(m, struct ip *); 1124 struct mbuf *p = NULL, *q, *nq; 1125 struct mbuf *n; 1126 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 1127 int i, next; 1128 #ifdef IPDIVERT 1129 struct m_tag *mtag; 1130 #endif 1131 1132 /* 1133 * Presence of header sizes in mbufs 1134 * would confuse code below. 1135 */ 1136 m->m_data += hlen; 1137 m->m_len -= hlen; 1138 1139 /* 1140 * If first fragment to arrive, create a reassembly queue. 1141 */ 1142 if (fp == NULL) { 1143 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1144 goto dropfrag; 1145 insque(fp, where); 1146 nipq++; 1147 fp->ipq_nfrags = 1; 1148 fp->ipq_ttl = IPFRAGTTL; 1149 fp->ipq_p = ip->ip_p; 1150 fp->ipq_id = ip->ip_id; 1151 fp->ipq_src = ip->ip_src; 1152 fp->ipq_dst = ip->ip_dst; 1153 fp->ipq_frags = m; 1154 m->m_nextpkt = NULL; 1155 #ifdef IPDIVERT 1156 fp->ipq_div_info = 0; 1157 #endif 1158 goto inserted; 1159 } else { 1160 fp->ipq_nfrags++; 1161 } 1162 1163 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1164 1165 /* 1166 * Find a segment which begins after this one does. 1167 */ 1168 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1169 if (GETIP(q)->ip_off > ip->ip_off) 1170 break; 1171 1172 /* 1173 * If there is a preceding segment, it may provide some of 1174 * our data already. If so, drop the data from the incoming 1175 * segment. If it provides all of our data, drop us, otherwise 1176 * stick new segment in the proper place. 1177 * 1178 * If some of the data is dropped from the the preceding 1179 * segment, then it's checksum is invalidated. 1180 */ 1181 if (p) { 1182 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1183 if (i > 0) { 1184 if (i >= ip->ip_len) 1185 goto dropfrag; 1186 m_adj(m, i); 1187 m->m_pkthdr.csum_flags = 0; 1188 ip->ip_off += i; 1189 ip->ip_len -= i; 1190 } 1191 m->m_nextpkt = p->m_nextpkt; 1192 p->m_nextpkt = m; 1193 } else { 1194 m->m_nextpkt = fp->ipq_frags; 1195 fp->ipq_frags = m; 1196 } 1197 1198 /* 1199 * While we overlap succeeding segments trim them or, 1200 * if they are completely covered, dequeue them. 1201 */ 1202 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1203 q = nq) { 1204 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1205 if (i < GETIP(q)->ip_len) { 1206 GETIP(q)->ip_len -= i; 1207 GETIP(q)->ip_off += i; 1208 m_adj(q, i); 1209 q->m_pkthdr.csum_flags = 0; 1210 break; 1211 } 1212 nq = q->m_nextpkt; 1213 m->m_nextpkt = nq; 1214 ipstat.ips_fragdropped++; 1215 fp->ipq_nfrags--; 1216 q->m_nextpkt = NULL; 1217 m_freem(q); 1218 } 1219 1220 inserted: 1221 1222 #ifdef IPDIVERT 1223 /* 1224 * Transfer firewall instructions to the fragment structure. 1225 * Only trust info in the fragment at offset 0. 1226 */ 1227 if (ip->ip_off == 0) { 1228 fp->ipq_div_info = *divinfo; 1229 } else { 1230 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 1231 if (mtag != NULL) 1232 m_tag_delete(m, mtag); 1233 } 1234 *divinfo = 0; 1235 #endif 1236 1237 /* 1238 * Check for complete reassembly and perform frag per packet 1239 * limiting. 1240 * 1241 * Frag limiting is performed here so that the nth frag has 1242 * a chance to complete the packet before we drop the packet. 1243 * As a result, n+1 frags are actually allowed per packet, but 1244 * only n will ever be stored. (n = maxfragsperpacket.) 1245 * 1246 */ 1247 next = 0; 1248 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1249 if (GETIP(q)->ip_off != next) { 1250 if (fp->ipq_nfrags > maxfragsperpacket) { 1251 ipstat.ips_fragdropped += fp->ipq_nfrags; 1252 ip_freef(fp); 1253 } 1254 return (NULL); 1255 } 1256 next += GETIP(q)->ip_len; 1257 } 1258 /* Make sure the last packet didn't have the IP_MF flag */ 1259 if (p->m_flags & M_FRAG) { 1260 if (fp->ipq_nfrags > maxfragsperpacket) { 1261 ipstat.ips_fragdropped += fp->ipq_nfrags; 1262 ip_freef(fp); 1263 } 1264 return (NULL); 1265 } 1266 1267 /* 1268 * Reassembly is complete. Make sure the packet is a sane size. 1269 */ 1270 q = fp->ipq_frags; 1271 ip = GETIP(q); 1272 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1273 ipstat.ips_toolong++; 1274 ipstat.ips_fragdropped += fp->ipq_nfrags; 1275 ip_freef(fp); 1276 return (NULL); 1277 } 1278 1279 /* 1280 * Concatenate fragments. 1281 */ 1282 m = q; 1283 n = m->m_next; 1284 m->m_next = NULL; 1285 m_cat(m, n); 1286 nq = q->m_nextpkt; 1287 q->m_nextpkt = NULL; 1288 for (q = nq; q != NULL; q = nq) { 1289 nq = q->m_nextpkt; 1290 q->m_nextpkt = NULL; 1291 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1292 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1293 m_cat(m, q); 1294 } 1295 1296 #ifdef IPDIVERT 1297 /* 1298 * Extract firewall instructions from the fragment structure. 1299 */ 1300 *divinfo = fp->ipq_div_info; 1301 #endif 1302 1303 /* 1304 * Create header for new ip packet by 1305 * modifying header of first packet; 1306 * dequeue and discard fragment reassembly header. 1307 * Make header visible. 1308 */ 1309 ip->ip_len = next; 1310 ip->ip_src = fp->ipq_src; 1311 ip->ip_dst = fp->ipq_dst; 1312 remque(fp); 1313 nipq--; 1314 mpipe_free(&ipq_mpipe, fp); 1315 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1316 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1317 /* some debugging cruft by sklower, below, will go away soon */ 1318 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1319 int plen = 0; 1320 1321 for (n = m; n; n = n->m_next) 1322 plen += n->m_len; 1323 m->m_pkthdr.len = plen; 1324 } 1325 return (m); 1326 1327 dropfrag: 1328 #ifdef IPDIVERT 1329 *divinfo = 0; 1330 #endif 1331 ipstat.ips_fragdropped++; 1332 if (fp != NULL) 1333 fp->ipq_nfrags--; 1334 m_freem(m); 1335 return (NULL); 1336 1337 #undef GETIP 1338 } 1339 1340 /* 1341 * Free a fragment reassembly header and all 1342 * associated datagrams. 1343 */ 1344 static void 1345 ip_freef(struct ipq *fp) 1346 { 1347 struct mbuf *q; 1348 1349 while (fp->ipq_frags) { 1350 q = fp->ipq_frags; 1351 fp->ipq_frags = q->m_nextpkt; 1352 q->m_nextpkt = NULL; 1353 m_freem(q); 1354 } 1355 remque(fp); 1356 mpipe_free(&ipq_mpipe, fp); 1357 nipq--; 1358 } 1359 1360 /* 1361 * IP timer processing; 1362 * if a timer expires on a reassembly 1363 * queue, discard it. 1364 */ 1365 void 1366 ip_slowtimo(void) 1367 { 1368 struct ipq *fp; 1369 int i; 1370 1371 crit_enter(); 1372 for (i = 0; i < IPREASS_NHASH; i++) { 1373 fp = ipq[i].next; 1374 if (fp == NULL) 1375 continue; 1376 while (fp != &ipq[i]) { 1377 --fp->ipq_ttl; 1378 fp = fp->next; 1379 if (fp->prev->ipq_ttl == 0) { 1380 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1381 ip_freef(fp->prev); 1382 } 1383 } 1384 } 1385 /* 1386 * If we are over the maximum number of fragments 1387 * (due to the limit being lowered), drain off 1388 * enough to get down to the new limit. 1389 */ 1390 if (maxnipq >= 0 && nipq > maxnipq) { 1391 for (i = 0; i < IPREASS_NHASH; i++) { 1392 while (nipq > maxnipq && 1393 (ipq[i].next != &ipq[i])) { 1394 ipstat.ips_fragdropped += 1395 ipq[i].next->ipq_nfrags; 1396 ip_freef(ipq[i].next); 1397 } 1398 } 1399 } 1400 ipflow_slowtimo(); 1401 crit_exit(); 1402 } 1403 1404 /* 1405 * Drain off all datagram fragments. 1406 */ 1407 void 1408 ip_drain(void) 1409 { 1410 int i; 1411 1412 for (i = 0; i < IPREASS_NHASH; i++) { 1413 while (ipq[i].next != &ipq[i]) { 1414 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1415 ip_freef(ipq[i].next); 1416 } 1417 } 1418 in_rtqdrain(); 1419 } 1420 1421 /* 1422 * Do option processing on a datagram, 1423 * possibly discarding it if bad options are encountered, 1424 * or forwarding it if source-routed. 1425 * The pass argument is used when operating in the IPSTEALTH 1426 * mode to tell what options to process: 1427 * [LS]SRR (pass 0) or the others (pass 1). 1428 * The reason for as many as two passes is that when doing IPSTEALTH, 1429 * non-routing options should be processed only if the packet is for us. 1430 * Returns 1 if packet has been forwarded/freed, 1431 * 0 if the packet should be processed further. 1432 */ 1433 static int 1434 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1435 { 1436 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1437 struct ip *ip = mtod(m, struct ip *); 1438 u_char *cp; 1439 struct in_ifaddr *ia; 1440 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1441 boolean_t forward = FALSE; 1442 struct in_addr *sin, dst; 1443 n_time ntime; 1444 1445 dst = ip->ip_dst; 1446 cp = (u_char *)(ip + 1); 1447 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1448 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1449 opt = cp[IPOPT_OPTVAL]; 1450 if (opt == IPOPT_EOL) 1451 break; 1452 if (opt == IPOPT_NOP) 1453 optlen = 1; 1454 else { 1455 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1456 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1457 goto bad; 1458 } 1459 optlen = cp[IPOPT_OLEN]; 1460 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1461 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1462 goto bad; 1463 } 1464 } 1465 switch (opt) { 1466 1467 default: 1468 break; 1469 1470 /* 1471 * Source routing with record. 1472 * Find interface with current destination address. 1473 * If none on this machine then drop if strictly routed, 1474 * or do nothing if loosely routed. 1475 * Record interface address and bring up next address 1476 * component. If strictly routed make sure next 1477 * address is on directly accessible net. 1478 */ 1479 case IPOPT_LSRR: 1480 case IPOPT_SSRR: 1481 if (ipstealth && pass > 0) 1482 break; 1483 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1484 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1485 goto bad; 1486 } 1487 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1488 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1489 goto bad; 1490 } 1491 ipaddr.sin_addr = ip->ip_dst; 1492 ia = (struct in_ifaddr *) 1493 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1494 if (ia == NULL) { 1495 if (opt == IPOPT_SSRR) { 1496 type = ICMP_UNREACH; 1497 code = ICMP_UNREACH_SRCFAIL; 1498 goto bad; 1499 } 1500 if (!ip_dosourceroute) 1501 goto nosourcerouting; 1502 /* 1503 * Loose routing, and not at next destination 1504 * yet; nothing to do except forward. 1505 */ 1506 break; 1507 } 1508 off--; /* 0 origin */ 1509 if (off > optlen - (int)sizeof(struct in_addr)) { 1510 /* 1511 * End of source route. Should be for us. 1512 */ 1513 if (!ip_acceptsourceroute) 1514 goto nosourcerouting; 1515 save_rte(cp, ip->ip_src); 1516 break; 1517 } 1518 if (ipstealth) 1519 goto dropit; 1520 if (!ip_dosourceroute) { 1521 if (ipforwarding) { 1522 char buf[sizeof "aaa.bbb.ccc.ddd"]; 1523 1524 /* 1525 * Acting as a router, so generate ICMP 1526 */ 1527 nosourcerouting: 1528 strcpy(buf, inet_ntoa(ip->ip_dst)); 1529 log(LOG_WARNING, 1530 "attempted source route from %s to %s\n", 1531 inet_ntoa(ip->ip_src), buf); 1532 type = ICMP_UNREACH; 1533 code = ICMP_UNREACH_SRCFAIL; 1534 goto bad; 1535 } else { 1536 /* 1537 * Not acting as a router, 1538 * so silently drop. 1539 */ 1540 dropit: 1541 ipstat.ips_cantforward++; 1542 m_freem(m); 1543 return (1); 1544 } 1545 } 1546 1547 /* 1548 * locate outgoing interface 1549 */ 1550 memcpy(&ipaddr.sin_addr, cp + off, 1551 sizeof ipaddr.sin_addr); 1552 1553 if (opt == IPOPT_SSRR) { 1554 #define INA struct in_ifaddr * 1555 #define SA struct sockaddr * 1556 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1557 == NULL) 1558 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1559 } else 1560 ia = ip_rtaddr(ipaddr.sin_addr, 1561 &ipforward_rt[mycpuid]); 1562 if (ia == NULL) { 1563 type = ICMP_UNREACH; 1564 code = ICMP_UNREACH_SRCFAIL; 1565 goto bad; 1566 } 1567 ip->ip_dst = ipaddr.sin_addr; 1568 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1569 sizeof(struct in_addr)); 1570 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1571 /* 1572 * Let ip_intr's mcast routing check handle mcast pkts 1573 */ 1574 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1575 break; 1576 1577 case IPOPT_RR: 1578 if (ipstealth && pass == 0) 1579 break; 1580 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1581 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1582 goto bad; 1583 } 1584 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1585 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1586 goto bad; 1587 } 1588 /* 1589 * If no space remains, ignore. 1590 */ 1591 off--; /* 0 origin */ 1592 if (off > optlen - (int)sizeof(struct in_addr)) 1593 break; 1594 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1595 sizeof ipaddr.sin_addr); 1596 /* 1597 * locate outgoing interface; if we're the destination, 1598 * use the incoming interface (should be same). 1599 */ 1600 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1601 (ia = ip_rtaddr(ipaddr.sin_addr, 1602 &ipforward_rt[mycpuid])) 1603 == NULL) { 1604 type = ICMP_UNREACH; 1605 code = ICMP_UNREACH_HOST; 1606 goto bad; 1607 } 1608 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1609 sizeof(struct in_addr)); 1610 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1611 break; 1612 1613 case IPOPT_TS: 1614 if (ipstealth && pass == 0) 1615 break; 1616 code = cp - (u_char *)ip; 1617 if (optlen < 4 || optlen > 40) { 1618 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1619 goto bad; 1620 } 1621 if ((off = cp[IPOPT_OFFSET]) < 5) { 1622 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1623 goto bad; 1624 } 1625 if (off > optlen - (int)sizeof(int32_t)) { 1626 cp[IPOPT_OFFSET + 1] += (1 << 4); 1627 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1628 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1629 goto bad; 1630 } 1631 break; 1632 } 1633 off--; /* 0 origin */ 1634 sin = (struct in_addr *)(cp + off); 1635 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1636 1637 case IPOPT_TS_TSONLY: 1638 break; 1639 1640 case IPOPT_TS_TSANDADDR: 1641 if (off + sizeof(n_time) + 1642 sizeof(struct in_addr) > optlen) { 1643 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1644 goto bad; 1645 } 1646 ipaddr.sin_addr = dst; 1647 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1648 m->m_pkthdr.rcvif); 1649 if (ia == NULL) 1650 continue; 1651 memcpy(sin, &IA_SIN(ia)->sin_addr, 1652 sizeof(struct in_addr)); 1653 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1654 off += sizeof(struct in_addr); 1655 break; 1656 1657 case IPOPT_TS_PRESPEC: 1658 if (off + sizeof(n_time) + 1659 sizeof(struct in_addr) > optlen) { 1660 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1661 goto bad; 1662 } 1663 memcpy(&ipaddr.sin_addr, sin, 1664 sizeof(struct in_addr)); 1665 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1666 continue; 1667 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1668 off += sizeof(struct in_addr); 1669 break; 1670 1671 default: 1672 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1673 goto bad; 1674 } 1675 ntime = iptime(); 1676 memcpy(cp + off, &ntime, sizeof(n_time)); 1677 cp[IPOPT_OFFSET] += sizeof(n_time); 1678 } 1679 } 1680 if (forward && ipforwarding) { 1681 ip_forward(m, TRUE, next_hop); 1682 return (1); 1683 } 1684 return (0); 1685 bad: 1686 icmp_error(m, type, code, 0, 0); 1687 ipstat.ips_badoptions++; 1688 return (1); 1689 } 1690 1691 /* 1692 * Given address of next destination (final or next hop), 1693 * return internet address info of interface to be used to get there. 1694 */ 1695 struct in_ifaddr * 1696 ip_rtaddr(struct in_addr dst, struct route *ro) 1697 { 1698 struct sockaddr_in *sin; 1699 1700 sin = (struct sockaddr_in *)&ro->ro_dst; 1701 1702 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1703 if (ro->ro_rt != NULL) { 1704 RTFREE(ro->ro_rt); 1705 ro->ro_rt = NULL; 1706 } 1707 sin->sin_family = AF_INET; 1708 sin->sin_len = sizeof *sin; 1709 sin->sin_addr = dst; 1710 rtalloc_ign(ro, RTF_PRCLONING); 1711 } 1712 1713 if (ro->ro_rt == NULL) 1714 return (NULL); 1715 1716 return (ifatoia(ro->ro_rt->rt_ifa)); 1717 } 1718 1719 /* 1720 * Save incoming source route for use in replies, 1721 * to be picked up later by ip_srcroute if the receiver is interested. 1722 */ 1723 void 1724 save_rte(u_char *option, struct in_addr dst) 1725 { 1726 unsigned olen; 1727 1728 olen = option[IPOPT_OLEN]; 1729 #ifdef DIAGNOSTIC 1730 if (ipprintfs) 1731 kprintf("save_rte: olen %d\n", olen); 1732 #endif 1733 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1734 return; 1735 bcopy(option, ip_srcrt.srcopt, olen); 1736 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1737 ip_srcrt.dst = dst; 1738 } 1739 1740 /* 1741 * Retrieve incoming source route for use in replies, 1742 * in the same form used by setsockopt. 1743 * The first hop is placed before the options, will be removed later. 1744 */ 1745 struct mbuf * 1746 ip_srcroute(void) 1747 { 1748 struct in_addr *p, *q; 1749 struct mbuf *m; 1750 1751 if (ip_nhops == 0) 1752 return (NULL); 1753 m = m_get(MB_DONTWAIT, MT_HEADER); 1754 if (m == NULL) 1755 return (NULL); 1756 1757 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1758 1759 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1760 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1761 OPTSIZ; 1762 #ifdef DIAGNOSTIC 1763 if (ipprintfs) 1764 kprintf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1765 #endif 1766 1767 /* 1768 * First save first hop for return route 1769 */ 1770 p = &ip_srcrt.route[ip_nhops - 1]; 1771 *(mtod(m, struct in_addr *)) = *p--; 1772 #ifdef DIAGNOSTIC 1773 if (ipprintfs) 1774 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1775 #endif 1776 1777 /* 1778 * Copy option fields and padding (nop) to mbuf. 1779 */ 1780 ip_srcrt.nop = IPOPT_NOP; 1781 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1782 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &ip_srcrt.nop, 1783 OPTSIZ); 1784 q = (struct in_addr *)(mtod(m, caddr_t) + 1785 sizeof(struct in_addr) + OPTSIZ); 1786 #undef OPTSIZ 1787 /* 1788 * Record return path as an IP source route, 1789 * reversing the path (pointers are now aligned). 1790 */ 1791 while (p >= ip_srcrt.route) { 1792 #ifdef DIAGNOSTIC 1793 if (ipprintfs) 1794 kprintf(" %x", ntohl(q->s_addr)); 1795 #endif 1796 *q++ = *p--; 1797 } 1798 /* 1799 * Last hop goes to final destination. 1800 */ 1801 *q = ip_srcrt.dst; 1802 #ifdef DIAGNOSTIC 1803 if (ipprintfs) 1804 kprintf(" %x\n", ntohl(q->s_addr)); 1805 #endif 1806 return (m); 1807 } 1808 1809 /* 1810 * Strip out IP options. 1811 */ 1812 void 1813 ip_stripoptions(struct mbuf *m) 1814 { 1815 int datalen; 1816 struct ip *ip = mtod(m, struct ip *); 1817 caddr_t opts; 1818 int optlen; 1819 1820 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1821 opts = (caddr_t)(ip + 1); 1822 datalen = m->m_len - (sizeof(struct ip) + optlen); 1823 bcopy(opts + optlen, opts, datalen); 1824 m->m_len -= optlen; 1825 if (m->m_flags & M_PKTHDR) 1826 m->m_pkthdr.len -= optlen; 1827 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1828 } 1829 1830 u_char inetctlerrmap[PRC_NCMDS] = { 1831 0, 0, 0, 0, 1832 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1833 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1834 EMSGSIZE, EHOSTUNREACH, 0, 0, 1835 0, 0, 0, 0, 1836 ENOPROTOOPT, ECONNREFUSED 1837 }; 1838 1839 /* 1840 * Forward a packet. If some error occurs return the sender 1841 * an icmp packet. Note we can't always generate a meaningful 1842 * icmp message because icmp doesn't have a large enough repertoire 1843 * of codes and types. 1844 * 1845 * If not forwarding, just drop the packet. This could be confusing 1846 * if ipforwarding was zero but some routing protocol was advancing 1847 * us as a gateway to somewhere. However, we must let the routing 1848 * protocol deal with that. 1849 * 1850 * The using_srcrt parameter indicates whether the packet is being forwarded 1851 * via a source route. 1852 */ 1853 static void 1854 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop) 1855 { 1856 struct ip *ip = mtod(m, struct ip *); 1857 struct sockaddr_in *ipforward_rtaddr; 1858 struct rtentry *rt; 1859 int error, type = 0, code = 0, destmtu = 0; 1860 struct mbuf *mcopy; 1861 n_long dest; 1862 struct in_addr pkt_dst; 1863 struct m_hdr tag; 1864 struct route *cache_rt = &ipforward_rt[mycpuid]; 1865 1866 dest = INADDR_ANY; 1867 /* 1868 * Cache the destination address of the packet; this may be 1869 * changed by use of 'ipfw fwd'. 1870 */ 1871 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 1872 1873 #ifdef DIAGNOSTIC 1874 if (ipprintfs) 1875 kprintf("forward: src %x dst %x ttl %x\n", 1876 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1877 #endif 1878 1879 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1880 ipstat.ips_cantforward++; 1881 m_freem(m); 1882 return; 1883 } 1884 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1885 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1886 return; 1887 } 1888 1889 ipforward_rtaddr = (struct sockaddr_in *) &cache_rt->ro_dst; 1890 if (cache_rt->ro_rt == NULL || 1891 ipforward_rtaddr->sin_addr.s_addr != pkt_dst.s_addr) { 1892 if (cache_rt->ro_rt != NULL) { 1893 RTFREE(cache_rt->ro_rt); 1894 cache_rt->ro_rt = NULL; 1895 } 1896 ipforward_rtaddr->sin_family = AF_INET; 1897 ipforward_rtaddr->sin_len = sizeof(struct sockaddr_in); 1898 ipforward_rtaddr->sin_addr = pkt_dst; 1899 rtalloc_ign(cache_rt, RTF_PRCLONING); 1900 if (cache_rt->ro_rt == NULL) { 1901 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1902 return; 1903 } 1904 } 1905 rt = cache_rt->ro_rt; 1906 1907 /* 1908 * Save the IP header and at most 8 bytes of the payload, 1909 * in case we need to generate an ICMP message to the src. 1910 * 1911 * XXX this can be optimized a lot by saving the data in a local 1912 * buffer on the stack (72 bytes at most), and only allocating the 1913 * mbuf if really necessary. The vast majority of the packets 1914 * are forwarded without having to send an ICMP back (either 1915 * because unnecessary, or because rate limited), so we are 1916 * really we are wasting a lot of work here. 1917 * 1918 * We don't use m_copy() because it might return a reference 1919 * to a shared cluster. Both this function and ip_output() 1920 * assume exclusive access to the IP header in `m', so any 1921 * data in a cluster may change before we reach icmp_error(). 1922 */ 1923 MGETHDR(mcopy, MB_DONTWAIT, m->m_type); 1924 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) { 1925 /* 1926 * It's probably ok if the pkthdr dup fails (because 1927 * the deep copy of the tag chain failed), but for now 1928 * be conservative and just discard the copy since 1929 * code below may some day want the tags. 1930 */ 1931 m_free(mcopy); 1932 mcopy = NULL; 1933 } 1934 if (mcopy != NULL) { 1935 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1936 (int)ip->ip_len); 1937 mcopy->m_pkthdr.len = mcopy->m_len; 1938 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1939 } 1940 1941 if (!ipstealth) 1942 ip->ip_ttl -= IPTTLDEC; 1943 1944 /* 1945 * If forwarding packet using same interface that it came in on, 1946 * perhaps should send a redirect to sender to shortcut a hop. 1947 * Only send redirect if source is sending directly to us, 1948 * and if packet was not source routed (or has any options). 1949 * Also, don't send redirect if forwarding using a default route 1950 * or a route modified by a redirect. 1951 */ 1952 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1953 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1954 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1955 ipsendredirects && !using_srcrt && next_hop == NULL) { 1956 u_long src = ntohl(ip->ip_src.s_addr); 1957 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa; 1958 1959 if (rt_ifa != NULL && 1960 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) { 1961 if (rt->rt_flags & RTF_GATEWAY) 1962 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1963 else 1964 dest = pkt_dst.s_addr; 1965 /* 1966 * Router requirements says to only send 1967 * host redirects. 1968 */ 1969 type = ICMP_REDIRECT; 1970 code = ICMP_REDIRECT_HOST; 1971 #ifdef DIAGNOSTIC 1972 if (ipprintfs) 1973 kprintf("redirect (%d) to %x\n", code, dest); 1974 #endif 1975 } 1976 } 1977 1978 if (next_hop != NULL) { 1979 /* Pass IPFORWARD info if available */ 1980 tag.mh_type = MT_TAG; 1981 tag.mh_flags = PACKET_TAG_IPFORWARD; 1982 tag.mh_data = (caddr_t)next_hop; 1983 tag.mh_next = m; 1984 m = (struct mbuf *)&tag; 1985 } 1986 1987 error = ip_output(m, NULL, cache_rt, IP_FORWARDING, NULL, 1988 NULL); 1989 if (error == 0) { 1990 ipstat.ips_forward++; 1991 if (type == 0) { 1992 if (mcopy) { 1993 ipflow_create(cache_rt, mcopy); 1994 m_freem(mcopy); 1995 } 1996 return; /* most common case */ 1997 } else { 1998 ipstat.ips_redirectsent++; 1999 } 2000 } else { 2001 ipstat.ips_cantforward++; 2002 } 2003 2004 if (mcopy == NULL) 2005 return; 2006 2007 /* 2008 * Send ICMP message. 2009 */ 2010 2011 switch (error) { 2012 2013 case 0: /* forwarded, but need redirect */ 2014 /* type, code set above */ 2015 break; 2016 2017 case ENETUNREACH: /* shouldn't happen, checked above */ 2018 case EHOSTUNREACH: 2019 case ENETDOWN: 2020 case EHOSTDOWN: 2021 default: 2022 type = ICMP_UNREACH; 2023 code = ICMP_UNREACH_HOST; 2024 break; 2025 2026 case EMSGSIZE: 2027 type = ICMP_UNREACH; 2028 code = ICMP_UNREACH_NEEDFRAG; 2029 #ifdef IPSEC 2030 /* 2031 * If the packet is routed over IPsec tunnel, tell the 2032 * originator the tunnel MTU. 2033 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2034 * XXX quickhack!!! 2035 */ 2036 if (cache_rt->ro_rt != NULL) { 2037 struct secpolicy *sp = NULL; 2038 int ipsecerror; 2039 int ipsechdr; 2040 struct route *ro; 2041 2042 sp = ipsec4_getpolicybyaddr(mcopy, 2043 IPSEC_DIR_OUTBOUND, 2044 IP_FORWARDING, 2045 &ipsecerror); 2046 2047 if (sp == NULL) 2048 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2049 else { 2050 /* count IPsec header size */ 2051 ipsechdr = ipsec4_hdrsiz(mcopy, 2052 IPSEC_DIR_OUTBOUND, 2053 NULL); 2054 2055 /* 2056 * find the correct route for outer IPv4 2057 * header, compute tunnel MTU. 2058 * 2059 */ 2060 if (sp->req != NULL && sp->req->sav != NULL && 2061 sp->req->sav->sah != NULL) { 2062 ro = &sp->req->sav->sah->sa_route; 2063 if (ro->ro_rt != NULL && 2064 ro->ro_rt->rt_ifp != NULL) { 2065 destmtu = 2066 ro->ro_rt->rt_ifp->if_mtu; 2067 destmtu -= ipsechdr; 2068 } 2069 } 2070 2071 key_freesp(sp); 2072 } 2073 } 2074 #elif FAST_IPSEC 2075 /* 2076 * If the packet is routed over IPsec tunnel, tell the 2077 * originator the tunnel MTU. 2078 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2079 * XXX quickhack!!! 2080 */ 2081 if (cache_rt->ro_rt != NULL) { 2082 struct secpolicy *sp = NULL; 2083 int ipsecerror; 2084 int ipsechdr; 2085 struct route *ro; 2086 2087 sp = ipsec_getpolicybyaddr(mcopy, 2088 IPSEC_DIR_OUTBOUND, 2089 IP_FORWARDING, 2090 &ipsecerror); 2091 2092 if (sp == NULL) 2093 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2094 else { 2095 /* count IPsec header size */ 2096 ipsechdr = ipsec4_hdrsiz(mcopy, 2097 IPSEC_DIR_OUTBOUND, 2098 NULL); 2099 2100 /* 2101 * find the correct route for outer IPv4 2102 * header, compute tunnel MTU. 2103 */ 2104 2105 if (sp->req != NULL && 2106 sp->req->sav != NULL && 2107 sp->req->sav->sah != NULL) { 2108 ro = &sp->req->sav->sah->sa_route; 2109 if (ro->ro_rt != NULL && 2110 ro->ro_rt->rt_ifp != NULL) { 2111 destmtu = 2112 ro->ro_rt->rt_ifp->if_mtu; 2113 destmtu -= ipsechdr; 2114 } 2115 } 2116 2117 KEY_FREESP(&sp); 2118 } 2119 } 2120 #else /* !IPSEC && !FAST_IPSEC */ 2121 if (cache_rt->ro_rt != NULL) 2122 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2123 #endif /*IPSEC*/ 2124 ipstat.ips_cantfrag++; 2125 break; 2126 2127 case ENOBUFS: 2128 /* 2129 * A router should not generate ICMP_SOURCEQUENCH as 2130 * required in RFC1812 Requirements for IP Version 4 Routers. 2131 * Source quench could be a big problem under DoS attacks, 2132 * or if the underlying interface is rate-limited. 2133 * Those who need source quench packets may re-enable them 2134 * via the net.inet.ip.sendsourcequench sysctl. 2135 */ 2136 if (!ip_sendsourcequench) { 2137 m_freem(mcopy); 2138 return; 2139 } else { 2140 type = ICMP_SOURCEQUENCH; 2141 code = 0; 2142 } 2143 break; 2144 2145 case EACCES: /* ipfw denied packet */ 2146 m_freem(mcopy); 2147 return; 2148 } 2149 icmp_error(mcopy, type, code, dest, destmtu); 2150 } 2151 2152 void 2153 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2154 struct mbuf *m) 2155 { 2156 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2157 struct timeval tv; 2158 2159 microtime(&tv); 2160 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2161 SCM_TIMESTAMP, SOL_SOCKET); 2162 if (*mp) 2163 mp = &(*mp)->m_next; 2164 } 2165 if (inp->inp_flags & INP_RECVDSTADDR) { 2166 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2167 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2168 if (*mp) 2169 mp = &(*mp)->m_next; 2170 } 2171 if (inp->inp_flags & INP_RECVTTL) { 2172 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2173 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2174 if (*mp) 2175 mp = &(*mp)->m_next; 2176 } 2177 #ifdef notyet 2178 /* XXX 2179 * Moving these out of udp_input() made them even more broken 2180 * than they already were. 2181 */ 2182 /* options were tossed already */ 2183 if (inp->inp_flags & INP_RECVOPTS) { 2184 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2185 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2186 if (*mp) 2187 mp = &(*mp)->m_next; 2188 } 2189 /* ip_srcroute doesn't do what we want here, need to fix */ 2190 if (inp->inp_flags & INP_RECVRETOPTS) { 2191 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2192 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2193 if (*mp) 2194 mp = &(*mp)->m_next; 2195 } 2196 #endif 2197 if (inp->inp_flags & INP_RECVIF) { 2198 struct ifnet *ifp; 2199 struct sdlbuf { 2200 struct sockaddr_dl sdl; 2201 u_char pad[32]; 2202 } sdlbuf; 2203 struct sockaddr_dl *sdp; 2204 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2205 2206 if (((ifp = m->m_pkthdr.rcvif)) && 2207 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2208 sdp = IF_LLSOCKADDR(ifp); 2209 /* 2210 * Change our mind and don't try copy. 2211 */ 2212 if ((sdp->sdl_family != AF_LINK) || 2213 (sdp->sdl_len > sizeof(sdlbuf))) { 2214 goto makedummy; 2215 } 2216 bcopy(sdp, sdl2, sdp->sdl_len); 2217 } else { 2218 makedummy: 2219 sdl2->sdl_len = 2220 offsetof(struct sockaddr_dl, sdl_data[0]); 2221 sdl2->sdl_family = AF_LINK; 2222 sdl2->sdl_index = 0; 2223 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2224 } 2225 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2226 IP_RECVIF, IPPROTO_IP); 2227 if (*mp) 2228 mp = &(*mp)->m_next; 2229 } 2230 } 2231 2232 /* 2233 * XXX these routines are called from the upper part of the kernel. 2234 * 2235 * They could also be moved to ip_mroute.c, since all the RSVP 2236 * handling is done there already. 2237 */ 2238 int 2239 ip_rsvp_init(struct socket *so) 2240 { 2241 if (so->so_type != SOCK_RAW || 2242 so->so_proto->pr_protocol != IPPROTO_RSVP) 2243 return EOPNOTSUPP; 2244 2245 if (ip_rsvpd != NULL) 2246 return EADDRINUSE; 2247 2248 ip_rsvpd = so; 2249 /* 2250 * This may seem silly, but we need to be sure we don't over-increment 2251 * the RSVP counter, in case something slips up. 2252 */ 2253 if (!ip_rsvp_on) { 2254 ip_rsvp_on = 1; 2255 rsvp_on++; 2256 } 2257 2258 return 0; 2259 } 2260 2261 int 2262 ip_rsvp_done(void) 2263 { 2264 ip_rsvpd = NULL; 2265 /* 2266 * This may seem silly, but we need to be sure we don't over-decrement 2267 * the RSVP counter, in case something slips up. 2268 */ 2269 if (ip_rsvp_on) { 2270 ip_rsvp_on = 0; 2271 rsvp_on--; 2272 } 2273 return 0; 2274 } 2275 2276 void 2277 rsvp_input(struct mbuf *m, ...) /* XXX must fixup manually */ 2278 { 2279 int off, proto; 2280 __va_list ap; 2281 2282 __va_start(ap, m); 2283 off = __va_arg(ap, int); 2284 proto = __va_arg(ap, int); 2285 __va_end(ap); 2286 2287 if (rsvp_input_p) { /* call the real one if loaded */ 2288 rsvp_input_p(m, off, proto); 2289 return; 2290 } 2291 2292 /* Can still get packets with rsvp_on = 0 if there is a local member 2293 * of the group to which the RSVP packet is addressed. But in this 2294 * case we want to throw the packet away. 2295 */ 2296 2297 if (!rsvp_on) { 2298 m_freem(m); 2299 return; 2300 } 2301 2302 if (ip_rsvpd != NULL) { 2303 rip_input(m, off, proto); 2304 return; 2305 } 2306 /* Drop the packet */ 2307 m_freem(m); 2308 } 2309