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 1.79 2008/04/20 13:44:25 swildner 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> 106 107 #include <netinet/in.h> 108 #include <netinet/in_systm.h> 109 #include <netinet/in_var.h> 110 #include <netinet/ip.h> 111 #include <netinet/in_pcb.h> 112 #include <netinet/ip_var.h> 113 #include <netinet/ip_icmp.h> 114 115 #include <sys/thread2.h> 116 #include <sys/msgport2.h> 117 #include <net/netmsg2.h> 118 119 #include <sys/socketvar.h> 120 121 #include <net/ipfw/ip_fw.h> 122 #include <net/dummynet/ip_dummynet.h> 123 124 #ifdef IPSEC 125 #include <netinet6/ipsec.h> 126 #include <netproto/key/key.h> 127 #endif 128 129 #ifdef FAST_IPSEC 130 #include <netproto/ipsec/ipsec.h> 131 #include <netproto/ipsec/key.h> 132 #endif 133 134 int rsvp_on = 0; 135 static int ip_rsvp_on; 136 struct socket *ip_rsvpd; 137 138 int ipforwarding = 0; 139 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 140 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 141 142 static int ipsendredirects = 1; /* XXX */ 143 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 144 &ipsendredirects, 0, "Enable sending IP redirects"); 145 146 int ip_defttl = IPDEFTTL; 147 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 148 &ip_defttl, 0, "Maximum TTL on IP packets"); 149 150 static int ip_dosourceroute = 0; 151 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 152 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 153 154 static int ip_acceptsourceroute = 0; 155 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 156 CTLFLAG_RW, &ip_acceptsourceroute, 0, 157 "Enable accepting source routed IP packets"); 158 159 static int ip_keepfaith = 0; 160 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 161 &ip_keepfaith, 0, 162 "Enable packet capture for FAITH IPv4->IPv6 translator daemon"); 163 164 static int nipq = 0; /* total # of reass queues */ 165 static int maxnipq; 166 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 167 &maxnipq, 0, 168 "Maximum number of IPv4 fragment reassembly queue entries"); 169 170 static int maxfragsperpacket; 171 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 172 &maxfragsperpacket, 0, 173 "Maximum number of IPv4 fragments allowed per packet"); 174 175 static int ip_sendsourcequench = 0; 176 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 177 &ip_sendsourcequench, 0, 178 "Enable the transmission of source quench packets"); 179 180 int ip_do_randomid = 1; 181 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 182 &ip_do_randomid, 0, 183 "Assign random ip_id values"); 184 /* 185 * XXX - Setting ip_checkinterface mostly implements the receive side of 186 * the Strong ES model described in RFC 1122, but since the routing table 187 * and transmit implementation do not implement the Strong ES model, 188 * setting this to 1 results in an odd hybrid. 189 * 190 * XXX - ip_checkinterface currently must be disabled if you use ipnat 191 * to translate the destination address to another local interface. 192 * 193 * XXX - ip_checkinterface must be disabled if you add IP aliases 194 * to the loopback interface instead of the interface where the 195 * packets for those addresses are received. 196 */ 197 static int ip_checkinterface = 0; 198 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 199 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 200 201 #ifdef DIAGNOSTIC 202 static int ipprintfs = 0; 203 #endif 204 205 extern struct domain inetdomain; 206 extern struct protosw inetsw[]; 207 u_char ip_protox[IPPROTO_MAX]; 208 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 209 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 210 u_long in_ifaddrhmask; /* mask for hash table */ 211 212 struct ip_stats ipstats_percpu[MAXCPU]; 213 #ifdef SMP 214 static int 215 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 216 { 217 int cpu, error = 0; 218 219 for (cpu = 0; cpu < ncpus; ++cpu) { 220 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu], 221 sizeof(struct ip_stats)))) 222 break; 223 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu], 224 sizeof(struct ip_stats)))) 225 break; 226 } 227 228 return (error); 229 } 230 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 231 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 232 #else 233 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 234 &ipstat, ip_stats, "IP statistics"); 235 #endif 236 237 /* Packet reassembly stuff */ 238 #define IPREASS_NHASH_LOG2 6 239 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 240 #define IPREASS_HMASK (IPREASS_NHASH - 1) 241 #define IPREASS_HASH(x,y) \ 242 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 243 244 static struct ipq ipq[IPREASS_NHASH]; 245 246 #ifdef IPCTL_DEFMTU 247 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 248 &ip_mtu, 0, "Default MTU"); 249 #endif 250 251 #ifdef IPSTEALTH 252 static int ipstealth = 0; 253 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, ""); 254 #else 255 static const int ipstealth = 0; 256 #endif 257 258 259 /* Firewall hooks */ 260 ip_fw_chk_t *ip_fw_chk_ptr; 261 ip_fw_dn_io_t *ip_fw_dn_io_ptr; 262 int fw_enable = 1; 263 int fw_one_pass = 1; 264 265 struct pfil_head inet_pfil_hook; 266 267 /* 268 * XXX this is ugly -- the following two global variables are 269 * used to store packet state while it travels through the stack. 270 * Note that the code even makes assumptions on the size and 271 * alignment of fields inside struct ip_srcrt so e.g. adding some 272 * fields will break the code. This needs to be fixed. 273 * 274 * We need to save the IP options in case a protocol wants to respond 275 * to an incoming packet over the same route if the packet got here 276 * using IP source routing. This allows connection establishment and 277 * maintenance when the remote end is on a network that is not known 278 * to us. 279 */ 280 static int ip_nhops = 0; 281 282 static struct ip_srcrt { 283 struct in_addr dst; /* final destination */ 284 char nop; /* one NOP to align */ 285 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 286 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 287 } ip_srcrt; 288 289 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 290 static struct malloc_pipe ipq_mpipe; 291 292 static void save_rte (u_char *, struct in_addr); 293 static int ip_dooptions (struct mbuf *m, int, 294 struct sockaddr_in *next_hop); 295 static void ip_forward (struct mbuf *m, boolean_t using_srcrt, 296 struct sockaddr_in *next_hop); 297 static void ip_freef (struct ipq *); 298 static void ip_input_handler (struct netmsg *); 299 static struct mbuf *ip_reass (struct mbuf *, struct ipq *, 300 struct ipq *, u_int32_t *); 301 302 /* 303 * IP initialization: fill in IP protocol switch table. 304 * All protocols not implemented in kernel go to raw IP protocol handler. 305 */ 306 void 307 ip_init(void) 308 { 309 struct protosw *pr; 310 int i; 311 #ifdef SMP 312 int cpu; 313 #endif 314 315 /* 316 * Make sure we can handle a reasonable number of fragments but 317 * cap it at 4000 (XXX). 318 */ 319 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 320 IFQ_MAXLEN, 4000, 0, NULL); 321 TAILQ_INIT(&in_ifaddrhead); 322 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 323 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 324 if (pr == NULL) 325 panic("ip_init"); 326 for (i = 0; i < IPPROTO_MAX; i++) 327 ip_protox[i] = pr - inetsw; 328 for (pr = inetdomain.dom_protosw; 329 pr < inetdomain.dom_protoswNPROTOSW; pr++) 330 if (pr->pr_domain->dom_family == PF_INET && 331 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 332 ip_protox[pr->pr_protocol] = pr - inetsw; 333 334 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 335 inet_pfil_hook.ph_af = AF_INET; 336 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) { 337 kprintf("%s: WARNING: unable to register pfil hook, " 338 "error %d\n", __func__, i); 339 } 340 341 for (i = 0; i < IPREASS_NHASH; i++) 342 ipq[i].next = ipq[i].prev = &ipq[i]; 343 344 maxnipq = nmbclusters / 32; 345 maxfragsperpacket = 16; 346 347 ip_id = time_second & 0xffff; 348 349 /* 350 * Initialize IP statistics counters for each CPU. 351 * 352 */ 353 #ifdef SMP 354 for (cpu = 0; cpu < ncpus; ++cpu) { 355 bzero(&ipstats_percpu[cpu], sizeof(struct ip_stats)); 356 } 357 #else 358 bzero(&ipstat, sizeof(struct ip_stats)); 359 #endif 360 361 netisr_register(NETISR_IP, ip_mport_in, ip_input_handler); 362 } 363 364 /* 365 * XXX watch out this one. It is perhaps used as a cache for 366 * the most recently used route ? it is cleared in in_addroute() 367 * when a new route is successfully created. 368 */ 369 struct route ipforward_rt[MAXCPU]; 370 371 /* Do transport protocol processing. */ 372 static void 373 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip, 374 struct sockaddr_in *nexthop) 375 { 376 /* 377 * Switch out to protocol's input routine. 378 */ 379 if (nexthop && ip->ip_p == IPPROTO_TCP) { 380 /* TCP needs IPFORWARD info if available */ 381 struct m_hdr tag; 382 383 tag.mh_type = MT_TAG; 384 tag.mh_flags = PACKET_TAG_IPFORWARD; 385 tag.mh_data = (caddr_t)nexthop; 386 tag.mh_next = m; 387 388 (*inetsw[ip_protox[ip->ip_p]].pr_input) 389 ((struct mbuf *)&tag, hlen, ip->ip_p); 390 } else { 391 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, ip->ip_p); 392 } 393 } 394 395 struct netmsg_transport_packet { 396 struct netmsg nm_netmsg; 397 struct mbuf *nm_mbuf; 398 int nm_hlen; 399 boolean_t nm_hasnexthop; 400 struct sockaddr_in nm_nexthop; 401 }; 402 403 static void 404 transport_processing_handler(netmsg_t netmsg) 405 { 406 struct netmsg_transport_packet *msg = (void *)netmsg; 407 struct sockaddr_in *nexthop; 408 struct ip *ip; 409 410 ip = mtod(msg->nm_mbuf, struct ip *); 411 nexthop = msg->nm_hasnexthop ? &msg->nm_nexthop : NULL; 412 transport_processing_oncpu(msg->nm_mbuf, msg->nm_hlen, ip, nexthop); 413 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0); 414 } 415 416 static void 417 ip_input_handler(struct netmsg *msg0) 418 { 419 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet; 420 421 ip_input(m); 422 /* msg0 was embedded in the mbuf, do not reply! */ 423 } 424 425 /* 426 * IP input routine. Checksum and byte swap header. If fragmented 427 * try to reassemble. Process options. Pass to next level. 428 */ 429 void 430 ip_input(struct mbuf *m) 431 { 432 struct ip *ip; 433 struct ipq *fp; 434 struct in_ifaddr *ia = NULL; 435 int i, hlen, checkif; 436 u_short sum; 437 struct in_addr pkt_dst; 438 u_int32_t divert_info = 0; /* packet divert/tee info */ 439 struct ip_fw_args args; 440 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 441 boolean_t needredispatch = FALSE; 442 struct in_addr odst; /* original dst address(NAT) */ 443 struct m_tag *mtag; 444 #ifdef FAST_IPSEC 445 struct tdb_ident *tdbi; 446 struct secpolicy *sp; 447 int error; 448 #endif 449 450 args.eh = NULL; 451 args.oif = NULL; 452 args.rule = NULL; 453 args.next_hop = NULL; 454 455 /* Grab info from MT_TAG mbufs prepended to the chain. */ 456 while (m != NULL && m->m_type == MT_TAG) { 457 switch(m->_m_tag_id) { 458 case PACKET_TAG_IPFORWARD: 459 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 460 break; 461 default: 462 kprintf("ip_input: unrecognised MT_TAG tag %d\n", 463 m->_m_tag_id); 464 break; 465 } 466 m = m->m_next; 467 } 468 M_ASSERTPKTHDR(m); 469 470 /* Extract info from dummynet tag */ 471 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL); 472 if (mtag != NULL) { 473 args.rule = ((struct dn_pkt *)m_tag_data(mtag))->dn_priv; 474 475 m_tag_delete(m, mtag); 476 mtag = NULL; 477 } 478 479 if (args.rule != NULL) { /* dummynet already filtered us */ 480 ip = mtod(m, struct ip *); 481 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 482 goto iphack; 483 } 484 485 ipstat.ips_total++; 486 487 /* length checks already done in ip_demux() */ 488 KASSERT(m->m_len >= sizeof(ip), ("IP header not in one mbuf")); 489 490 ip = mtod(m, struct ip *); 491 492 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 493 ipstat.ips_badvers++; 494 goto bad; 495 } 496 497 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 498 /* length checks already done in ip_demux() */ 499 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 500 KASSERT(m->m_len >= hlen, ("packet shorter than IP header length")); 501 502 /* 127/8 must not appear on wire - RFC1122 */ 503 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 504 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 505 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 506 ipstat.ips_badaddr++; 507 goto bad; 508 } 509 } 510 511 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 512 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 513 } else { 514 if (hlen == sizeof(struct ip)) { 515 sum = in_cksum_hdr(ip); 516 } else { 517 sum = in_cksum(m, hlen); 518 } 519 } 520 if (sum != 0) { 521 ipstat.ips_badsum++; 522 goto bad; 523 } 524 525 #ifdef ALTQ 526 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 527 /* packet is dropped by traffic conditioner */ 528 return; 529 } 530 #endif 531 /* 532 * Convert fields to host representation. 533 */ 534 ip->ip_len = ntohs(ip->ip_len); 535 if (ip->ip_len < hlen) { 536 ipstat.ips_badlen++; 537 goto bad; 538 } 539 ip->ip_off = ntohs(ip->ip_off); 540 541 /* 542 * Check that the amount of data in the buffers 543 * is as at least much as the IP header would have us expect. 544 * Trim mbufs if longer than we expect. 545 * Drop packet if shorter than we expect. 546 */ 547 if (m->m_pkthdr.len < ip->ip_len) { 548 ipstat.ips_tooshort++; 549 goto bad; 550 } 551 if (m->m_pkthdr.len > ip->ip_len) { 552 if (m->m_len == m->m_pkthdr.len) { 553 m->m_len = ip->ip_len; 554 m->m_pkthdr.len = ip->ip_len; 555 } else 556 m_adj(m, ip->ip_len - m->m_pkthdr.len); 557 } 558 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 559 /* 560 * Bypass packet filtering for packets from a tunnel (gif). 561 */ 562 if (ipsec_gethist(m, NULL)) 563 goto pass; 564 #endif 565 566 /* 567 * IpHack's section. 568 * Right now when no processing on packet has done 569 * and it is still fresh out of network we do our black 570 * deals with it. 571 * - Firewall: deny/allow/divert 572 * - Xlate: translate packet's addr/port (NAT). 573 * - Pipe: pass pkt through dummynet. 574 * - Wrap: fake packet's addr/port <unimpl.> 575 * - Encapsulate: put it in another IP and send out. <unimp.> 576 */ 577 578 iphack: 579 580 /* 581 * Run through list of hooks for input packets. 582 * 583 * NB: Beware of the destination address changing (e.g. 584 * by NAT rewriting). When this happens, tell 585 * ip_forward to do the right thing. 586 */ 587 if (pfil_has_hooks(&inet_pfil_hook)) { 588 odst = ip->ip_dst; 589 if (pfil_run_hooks(&inet_pfil_hook, &m, 590 m->m_pkthdr.rcvif, PFIL_IN)) { 591 return; 592 } 593 if (m == NULL) /* consumed by filter */ 594 return; 595 ip = mtod(m, struct ip *); 596 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 597 } 598 599 if (fw_enable && IPFW_LOADED) { 600 /* 601 * If we've been forwarded from the output side, then 602 * skip the firewall a second time 603 */ 604 if (args.next_hop != NULL) 605 goto ours; 606 607 args.m = m; 608 i = ip_fw_chk_ptr(&args); 609 m = args.m; 610 611 if ((i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 612 if (m != NULL) 613 m_freem(m); 614 return; 615 } 616 ip = mtod(m, struct ip *); /* just in case m changed */ 617 if (i == 0 && args.next_hop == NULL) /* common case */ 618 goto pass; 619 if (i & IP_FW_PORT_DYNT_FLAG) { 620 /* Send packet to the appropriate pipe */ 621 ip_fw_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 622 return; 623 } 624 #ifdef IPDIVERT 625 if (i != 0 && !(i & IP_FW_PORT_DYNT_FLAG)) { 626 /* Divert or tee packet */ 627 divert_info = i; 628 goto ours; 629 } 630 #endif 631 if (i == 0 && args.next_hop != NULL) 632 goto pass; 633 /* 634 * if we get here, the packet must be dropped 635 */ 636 m_freem(m); 637 return; 638 } 639 pass: 640 641 /* 642 * Process options and, if not destined for us, 643 * ship it on. ip_dooptions returns 1 when an 644 * error was detected (causing an icmp message 645 * to be sent and the original packet to be freed). 646 */ 647 ip_nhops = 0; /* for source routed packets */ 648 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, args.next_hop)) 649 return; 650 651 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 652 * matter if it is destined to another node, or whether it is 653 * a multicast one, RSVP wants it! and prevents it from being forwarded 654 * anywhere else. Also checks if the rsvp daemon is running before 655 * grabbing the packet. 656 */ 657 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 658 goto ours; 659 660 /* 661 * Check our list of addresses, to see if the packet is for us. 662 * If we don't have any addresses, assume any unicast packet 663 * we receive might be for us (and let the upper layers deal 664 * with it). 665 */ 666 if (TAILQ_EMPTY(&in_ifaddrhead) && !(m->m_flags & (M_MCAST | M_BCAST))) 667 goto ours; 668 669 /* 670 * Cache the destination address of the packet; this may be 671 * changed by use of 'ipfw fwd'. 672 */ 673 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 674 675 /* 676 * Enable a consistency check between the destination address 677 * and the arrival interface for a unicast packet (the RFC 1122 678 * strong ES model) if IP forwarding is disabled and the packet 679 * is not locally generated and the packet is not subject to 680 * 'ipfw fwd'. 681 * 682 * XXX - Checking also should be disabled if the destination 683 * address is ipnat'ed to a different interface. 684 * 685 * XXX - Checking is incompatible with IP aliases added 686 * to the loopback interface instead of the interface where 687 * the packets are received. 688 */ 689 checkif = ip_checkinterface && 690 !ipforwarding && 691 m->m_pkthdr.rcvif != NULL && 692 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 693 (args.next_hop == NULL); 694 695 /* 696 * Check for exact addresses in the hash bucket. 697 */ 698 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 699 /* 700 * If the address matches, verify that the packet 701 * arrived via the correct interface if checking is 702 * enabled. 703 */ 704 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 705 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 706 goto ours; 707 } 708 /* 709 * Check for broadcast addresses. 710 * 711 * Only accept broadcast packets that arrive via the matching 712 * interface. Reception of forwarded directed broadcasts would 713 * be handled via ip_forward() and ether_output() with the loopback 714 * into the stack for SIMPLEX interfaces handled by ether_output(). 715 */ 716 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 717 struct ifaddr_container *ifac; 718 719 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 720 ifa_link) { 721 struct ifaddr *ifa = ifac->ifa; 722 723 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 724 continue; 725 if (ifa->ifa_addr->sa_family != AF_INET) 726 continue; 727 ia = ifatoia(ifa); 728 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 729 pkt_dst.s_addr) 730 goto ours; 731 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 732 goto ours; 733 #ifdef BOOTP_COMPAT 734 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 735 goto ours; 736 #endif 737 } 738 } 739 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 740 struct in_multi *inm; 741 742 if (ip_mrouter != NULL) { 743 /* 744 * If we are acting as a multicast router, all 745 * incoming multicast packets are passed to the 746 * kernel-level multicast forwarding function. 747 * The packet is returned (relatively) intact; if 748 * ip_mforward() returns a non-zero value, the packet 749 * must be discarded, else it may be accepted below. 750 */ 751 if (ip_mforward != NULL && 752 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 753 ipstat.ips_cantforward++; 754 m_freem(m); 755 return; 756 } 757 758 /* 759 * The process-level routing daemon needs to receive 760 * all multicast IGMP packets, whether or not this 761 * host belongs to their destination groups. 762 */ 763 if (ip->ip_p == IPPROTO_IGMP) 764 goto ours; 765 ipstat.ips_forward++; 766 } 767 /* 768 * See if we belong to the destination multicast group on the 769 * arrival interface. 770 */ 771 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 772 if (inm == NULL) { 773 ipstat.ips_notmember++; 774 m_freem(m); 775 return; 776 } 777 goto ours; 778 } 779 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 780 goto ours; 781 if (ip->ip_dst.s_addr == INADDR_ANY) 782 goto ours; 783 784 /* 785 * FAITH(Firewall Aided Internet Translator) 786 */ 787 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 788 if (ip_keepfaith) { 789 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 790 goto ours; 791 } 792 m_freem(m); 793 return; 794 } 795 796 /* 797 * Not for us; forward if possible and desirable. 798 */ 799 if (!ipforwarding) { 800 ipstat.ips_cantforward++; 801 m_freem(m); 802 } else { 803 #ifdef IPSEC 804 /* 805 * Enforce inbound IPsec SPD. 806 */ 807 if (ipsec4_in_reject(m, NULL)) { 808 ipsecstat.in_polvio++; 809 goto bad; 810 } 811 #endif 812 #ifdef FAST_IPSEC 813 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 814 crit_enter(); 815 if (mtag != NULL) { 816 tdbi = (struct tdb_ident *)m_tag_data(mtag); 817 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 818 } else { 819 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 820 IP_FORWARDING, &error); 821 } 822 if (sp == NULL) { /* NB: can happen if error */ 823 crit_exit(); 824 /*XXX error stat???*/ 825 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 826 goto bad; 827 } 828 829 /* 830 * Check security policy against packet attributes. 831 */ 832 error = ipsec_in_reject(sp, m); 833 KEY_FREESP(&sp); 834 crit_exit(); 835 if (error) { 836 ipstat.ips_cantforward++; 837 goto bad; 838 } 839 #endif 840 ip_forward(m, using_srcrt, args.next_hop); 841 } 842 return; 843 844 ours: 845 846 /* 847 * IPSTEALTH: Process non-routing options only 848 * if the packet is destined for us. 849 */ 850 if (ipstealth && 851 hlen > sizeof(struct ip) && 852 ip_dooptions(m, 1, args.next_hop)) 853 return; 854 855 /* Count the packet in the ip address stats */ 856 if (ia != NULL) { 857 ia->ia_ifa.if_ipackets++; 858 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 859 } 860 861 /* 862 * If offset or IP_MF are set, must reassemble. 863 * Otherwise, nothing need be done. 864 * (We could look in the reassembly queue to see 865 * if the packet was previously fragmented, 866 * but it's not worth the time; just let them time out.) 867 */ 868 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 869 870 /* If maxnipq is 0, never accept fragments. */ 871 if (maxnipq == 0) { 872 ipstat.ips_fragments++; 873 ipstat.ips_fragdropped++; 874 goto bad; 875 } 876 877 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 878 /* 879 * Look for queue of fragments 880 * of this datagram. 881 */ 882 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 883 if (ip->ip_id == fp->ipq_id && 884 ip->ip_src.s_addr == fp->ipq_src.s_addr && 885 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 886 ip->ip_p == fp->ipq_p) 887 goto found; 888 889 fp = NULL; 890 891 /* 892 * Enforce upper bound on number of fragmented packets 893 * for which we attempt reassembly; 894 * If maxnipq is -1, accept all fragments without limitation. 895 */ 896 if ((nipq > maxnipq) && (maxnipq > 0)) { 897 /* 898 * drop something from the tail of the current queue 899 * before proceeding further 900 */ 901 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 902 for (i = 0; i < IPREASS_NHASH; i++) { 903 if (ipq[i].prev != &ipq[i]) { 904 ipstat.ips_fragtimeout += 905 ipq[i].prev->ipq_nfrags; 906 ip_freef(ipq[i].prev); 907 break; 908 } 909 } 910 } else { 911 ipstat.ips_fragtimeout += 912 ipq[sum].prev->ipq_nfrags; 913 ip_freef(ipq[sum].prev); 914 } 915 } 916 found: 917 /* 918 * Adjust ip_len to not reflect header, 919 * convert offset of this to bytes. 920 */ 921 ip->ip_len -= hlen; 922 if (ip->ip_off & IP_MF) { 923 /* 924 * Make sure that fragments have a data length 925 * that's a non-zero multiple of 8 bytes. 926 */ 927 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 928 ipstat.ips_toosmall++; /* XXX */ 929 goto bad; 930 } 931 m->m_flags |= M_FRAG; 932 } else 933 m->m_flags &= ~M_FRAG; 934 ip->ip_off <<= 3; 935 936 /* 937 * Attempt reassembly; if it succeeds, proceed. 938 * ip_reass() will return a different mbuf, and update 939 * the divert info in divert_info. 940 */ 941 ipstat.ips_fragments++; 942 m->m_pkthdr.header = ip; 943 m = ip_reass(m, fp, &ipq[sum], &divert_info); 944 if (m == NULL) 945 return; 946 ipstat.ips_reassembled++; 947 needredispatch = TRUE; 948 ip = mtod(m, struct ip *); 949 /* Get the header length of the reassembled packet */ 950 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 951 #ifdef IPDIVERT 952 /* Restore original checksum before diverting packet */ 953 if (divert_info != 0) { 954 ip->ip_len += hlen; 955 ip->ip_len = htons(ip->ip_len); 956 ip->ip_off = htons(ip->ip_off); 957 ip->ip_sum = 0; 958 if (hlen == sizeof(struct ip)) 959 ip->ip_sum = in_cksum_hdr(ip); 960 else 961 ip->ip_sum = in_cksum(m, hlen); 962 ip->ip_off = ntohs(ip->ip_off); 963 ip->ip_len = ntohs(ip->ip_len); 964 ip->ip_len -= hlen; 965 } 966 #endif 967 } else { 968 ip->ip_len -= hlen; 969 } 970 971 #ifdef IPDIVERT 972 /* 973 * Divert or tee packet to the divert protocol if required. 974 */ 975 if (divert_info != 0) { 976 struct mbuf *clone = NULL; 977 978 /* Clone packet if we're doing a 'tee' */ 979 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 980 clone = m_dup(m, MB_DONTWAIT); 981 982 /* Restore packet header fields to original values */ 983 ip->ip_len += hlen; 984 ip->ip_len = htons(ip->ip_len); 985 ip->ip_off = htons(ip->ip_off); 986 987 /* Deliver packet to divert input routine */ 988 divert_packet(m, 1, divert_info & 0xffff); 989 ipstat.ips_delivered++; 990 991 /* If 'tee', continue with original packet */ 992 if (clone == NULL) 993 return; 994 m = clone; 995 ip = mtod(m, struct ip *); 996 ip->ip_len += hlen; 997 /* 998 * Jump backwards to complete processing of the 999 * packet. But first clear divert_info to avoid 1000 * entering this block again. 1001 * We do not need to clear args.divert_rule 1002 * or args.next_hop as they will not be used. 1003 * 1004 * XXX Better safe than sorry, remove the DIVERT tag. 1005 */ 1006 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 1007 if (mtag != NULL) 1008 m_tag_delete(m, mtag); 1009 1010 divert_info = 0; 1011 goto pass; 1012 } 1013 #endif 1014 1015 #ifdef IPSEC 1016 /* 1017 * enforce IPsec policy checking if we are seeing last header. 1018 * note that we do not visit this with protocols with pcb layer 1019 * code - like udp/tcp/raw ip. 1020 */ 1021 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 1022 ipsec4_in_reject(m, NULL)) { 1023 ipsecstat.in_polvio++; 1024 goto bad; 1025 } 1026 #endif 1027 #if FAST_IPSEC 1028 /* 1029 * enforce IPsec policy checking if we are seeing last header. 1030 * note that we do not visit this with protocols with pcb layer 1031 * code - like udp/tcp/raw ip. 1032 */ 1033 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 1034 /* 1035 * Check if the packet has already had IPsec processing 1036 * done. If so, then just pass it along. This tag gets 1037 * set during AH, ESP, etc. input handling, before the 1038 * packet is returned to the ip input queue for delivery. 1039 */ 1040 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 1041 crit_enter(); 1042 if (mtag != NULL) { 1043 tdbi = (struct tdb_ident *)m_tag_data(mtag); 1044 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 1045 } else { 1046 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 1047 IP_FORWARDING, &error); 1048 } 1049 if (sp != NULL) { 1050 /* 1051 * Check security policy against packet attributes. 1052 */ 1053 error = ipsec_in_reject(sp, m); 1054 KEY_FREESP(&sp); 1055 } else { 1056 /* XXX error stat??? */ 1057 error = EINVAL; 1058 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 1059 goto bad; 1060 } 1061 crit_exit(); 1062 if (error) 1063 goto bad; 1064 } 1065 #endif /* FAST_IPSEC */ 1066 1067 ipstat.ips_delivered++; 1068 if (needredispatch) { 1069 struct netmsg_transport_packet *msg; 1070 lwkt_port_t port; 1071 1072 ip->ip_off = htons(ip->ip_off); 1073 ip->ip_len = htons(ip->ip_len); 1074 port = ip_mport_in(&m); 1075 if (port == NULL) 1076 return; 1077 1078 msg = kmalloc(sizeof(struct netmsg_transport_packet), M_LWKTMSG, 1079 M_INTWAIT | M_NULLOK); 1080 if (msg == NULL) 1081 goto bad; 1082 1083 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0, 1084 transport_processing_handler); 1085 msg->nm_hlen = hlen; 1086 msg->nm_hasnexthop = (args.next_hop != NULL); 1087 if (msg->nm_hasnexthop) 1088 msg->nm_nexthop = *args.next_hop; /* structure copy */ 1089 1090 msg->nm_mbuf = m; 1091 ip = mtod(m, struct ip *); 1092 ip->ip_len = ntohs(ip->ip_len); 1093 ip->ip_off = ntohs(ip->ip_off); 1094 lwkt_sendmsg(port, &msg->nm_netmsg.nm_lmsg); 1095 } else { 1096 transport_processing_oncpu(m, hlen, ip, args.next_hop); 1097 } 1098 return; 1099 1100 bad: 1101 m_freem(m); 1102 } 1103 1104 /* 1105 * Take incoming datagram fragment and try to reassemble it into 1106 * whole datagram. If a chain for reassembly of this datagram already 1107 * exists, then it is given as fp; otherwise have to make a chain. 1108 * 1109 * When IPDIVERT enabled, keep additional state with each packet that 1110 * tells us if we need to divert or tee the packet we're building. 1111 * In particular, *divinfo includes the port and TEE flag. 1112 */ 1113 1114 static struct mbuf * 1115 ip_reass(struct mbuf *m, struct ipq *fp, struct ipq *where, 1116 u_int32_t *divinfo) 1117 { 1118 struct ip *ip = mtod(m, struct ip *); 1119 struct mbuf *p = NULL, *q, *nq; 1120 struct mbuf *n; 1121 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 1122 int i, next; 1123 #ifdef IPDIVERT 1124 struct m_tag *mtag; 1125 #endif 1126 1127 /* 1128 * If the hardware has not done csum over this fragment 1129 * then csum_data is not valid at all. 1130 */ 1131 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) 1132 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) { 1133 m->m_pkthdr.csum_data = 0; 1134 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR); 1135 } 1136 1137 /* 1138 * Presence of header sizes in mbufs 1139 * would confuse code below. 1140 */ 1141 m->m_data += hlen; 1142 m->m_len -= hlen; 1143 1144 /* 1145 * If first fragment to arrive, create a reassembly queue. 1146 */ 1147 if (fp == NULL) { 1148 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1149 goto dropfrag; 1150 insque(fp, where); 1151 nipq++; 1152 fp->ipq_nfrags = 1; 1153 fp->ipq_ttl = IPFRAGTTL; 1154 fp->ipq_p = ip->ip_p; 1155 fp->ipq_id = ip->ip_id; 1156 fp->ipq_src = ip->ip_src; 1157 fp->ipq_dst = ip->ip_dst; 1158 fp->ipq_frags = m; 1159 m->m_nextpkt = NULL; 1160 #ifdef IPDIVERT 1161 fp->ipq_div_info = 0; 1162 #endif 1163 goto inserted; 1164 } else { 1165 fp->ipq_nfrags++; 1166 } 1167 1168 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1169 1170 /* 1171 * Find a segment which begins after this one does. 1172 */ 1173 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1174 if (GETIP(q)->ip_off > ip->ip_off) 1175 break; 1176 1177 /* 1178 * If there is a preceding segment, it may provide some of 1179 * our data already. If so, drop the data from the incoming 1180 * segment. If it provides all of our data, drop us, otherwise 1181 * stick new segment in the proper place. 1182 * 1183 * If some of the data is dropped from the the preceding 1184 * segment, then it's checksum is invalidated. 1185 */ 1186 if (p) { 1187 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1188 if (i > 0) { 1189 if (i >= ip->ip_len) 1190 goto dropfrag; 1191 m_adj(m, i); 1192 m->m_pkthdr.csum_flags = 0; 1193 ip->ip_off += i; 1194 ip->ip_len -= i; 1195 } 1196 m->m_nextpkt = p->m_nextpkt; 1197 p->m_nextpkt = m; 1198 } else { 1199 m->m_nextpkt = fp->ipq_frags; 1200 fp->ipq_frags = m; 1201 } 1202 1203 /* 1204 * While we overlap succeeding segments trim them or, 1205 * if they are completely covered, dequeue them. 1206 */ 1207 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1208 q = nq) { 1209 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1210 if (i < GETIP(q)->ip_len) { 1211 GETIP(q)->ip_len -= i; 1212 GETIP(q)->ip_off += i; 1213 m_adj(q, i); 1214 q->m_pkthdr.csum_flags = 0; 1215 break; 1216 } 1217 nq = q->m_nextpkt; 1218 m->m_nextpkt = nq; 1219 ipstat.ips_fragdropped++; 1220 fp->ipq_nfrags--; 1221 q->m_nextpkt = NULL; 1222 m_freem(q); 1223 } 1224 1225 inserted: 1226 1227 #ifdef IPDIVERT 1228 /* 1229 * Transfer firewall instructions to the fragment structure. 1230 * Only trust info in the fragment at offset 0. 1231 */ 1232 if (ip->ip_off == 0) { 1233 fp->ipq_div_info = *divinfo; 1234 } else { 1235 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 1236 if (mtag != NULL) 1237 m_tag_delete(m, mtag); 1238 } 1239 *divinfo = 0; 1240 #endif 1241 1242 /* 1243 * Check for complete reassembly and perform frag per packet 1244 * limiting. 1245 * 1246 * Frag limiting is performed here so that the nth frag has 1247 * a chance to complete the packet before we drop the packet. 1248 * As a result, n+1 frags are actually allowed per packet, but 1249 * only n will ever be stored. (n = maxfragsperpacket.) 1250 * 1251 */ 1252 next = 0; 1253 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1254 if (GETIP(q)->ip_off != next) { 1255 if (fp->ipq_nfrags > maxfragsperpacket) { 1256 ipstat.ips_fragdropped += fp->ipq_nfrags; 1257 ip_freef(fp); 1258 } 1259 return (NULL); 1260 } 1261 next += GETIP(q)->ip_len; 1262 } 1263 /* Make sure the last packet didn't have the IP_MF flag */ 1264 if (p->m_flags & M_FRAG) { 1265 if (fp->ipq_nfrags > maxfragsperpacket) { 1266 ipstat.ips_fragdropped += fp->ipq_nfrags; 1267 ip_freef(fp); 1268 } 1269 return (NULL); 1270 } 1271 1272 /* 1273 * Reassembly is complete. Make sure the packet is a sane size. 1274 */ 1275 q = fp->ipq_frags; 1276 ip = GETIP(q); 1277 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1278 ipstat.ips_toolong++; 1279 ipstat.ips_fragdropped += fp->ipq_nfrags; 1280 ip_freef(fp); 1281 return (NULL); 1282 } 1283 1284 /* 1285 * Concatenate fragments. 1286 */ 1287 m = q; 1288 n = m->m_next; 1289 m->m_next = NULL; 1290 m_cat(m, n); 1291 nq = q->m_nextpkt; 1292 q->m_nextpkt = NULL; 1293 for (q = nq; q != NULL; q = nq) { 1294 nq = q->m_nextpkt; 1295 q->m_nextpkt = NULL; 1296 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1297 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1298 m_cat(m, q); 1299 } 1300 1301 /* 1302 * Clean up the 1's complement checksum. Carry over 16 bits must 1303 * be added back. This assumes no more then 65535 packet fragments 1304 * were reassembled. A second carry can also occur (but not a third). 1305 */ 1306 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + 1307 (m->m_pkthdr.csum_data >> 16); 1308 if (m->m_pkthdr.csum_data > 0xFFFF) 1309 m->m_pkthdr.csum_data -= 0xFFFF; 1310 1311 1312 #ifdef IPDIVERT 1313 /* 1314 * Extract firewall instructions from the fragment structure. 1315 */ 1316 *divinfo = fp->ipq_div_info; 1317 #endif 1318 1319 /* 1320 * Create header for new ip packet by 1321 * modifying header of first packet; 1322 * dequeue and discard fragment reassembly header. 1323 * Make header visible. 1324 */ 1325 ip->ip_len = next; 1326 ip->ip_src = fp->ipq_src; 1327 ip->ip_dst = fp->ipq_dst; 1328 remque(fp); 1329 nipq--; 1330 mpipe_free(&ipq_mpipe, fp); 1331 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1332 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1333 /* some debugging cruft by sklower, below, will go away soon */ 1334 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1335 int plen = 0; 1336 1337 for (n = m; n; n = n->m_next) 1338 plen += n->m_len; 1339 m->m_pkthdr.len = plen; 1340 } 1341 return (m); 1342 1343 dropfrag: 1344 #ifdef IPDIVERT 1345 *divinfo = 0; 1346 #endif 1347 ipstat.ips_fragdropped++; 1348 if (fp != NULL) 1349 fp->ipq_nfrags--; 1350 m_freem(m); 1351 return (NULL); 1352 1353 #undef GETIP 1354 } 1355 1356 /* 1357 * Free a fragment reassembly header and all 1358 * associated datagrams. 1359 */ 1360 static void 1361 ip_freef(struct ipq *fp) 1362 { 1363 struct mbuf *q; 1364 1365 while (fp->ipq_frags) { 1366 q = fp->ipq_frags; 1367 fp->ipq_frags = q->m_nextpkt; 1368 q->m_nextpkt = NULL; 1369 m_freem(q); 1370 } 1371 remque(fp); 1372 mpipe_free(&ipq_mpipe, fp); 1373 nipq--; 1374 } 1375 1376 /* 1377 * IP timer processing; 1378 * if a timer expires on a reassembly 1379 * queue, discard it. 1380 */ 1381 void 1382 ip_slowtimo(void) 1383 { 1384 struct ipq *fp; 1385 int i; 1386 1387 crit_enter(); 1388 for (i = 0; i < IPREASS_NHASH; i++) { 1389 fp = ipq[i].next; 1390 if (fp == NULL) 1391 continue; 1392 while (fp != &ipq[i]) { 1393 --fp->ipq_ttl; 1394 fp = fp->next; 1395 if (fp->prev->ipq_ttl == 0) { 1396 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1397 ip_freef(fp->prev); 1398 } 1399 } 1400 } 1401 /* 1402 * If we are over the maximum number of fragments 1403 * (due to the limit being lowered), drain off 1404 * enough to get down to the new limit. 1405 */ 1406 if (maxnipq >= 0 && nipq > maxnipq) { 1407 for (i = 0; i < IPREASS_NHASH; i++) { 1408 while (nipq > maxnipq && 1409 (ipq[i].next != &ipq[i])) { 1410 ipstat.ips_fragdropped += 1411 ipq[i].next->ipq_nfrags; 1412 ip_freef(ipq[i].next); 1413 } 1414 } 1415 } 1416 ipflow_slowtimo(); 1417 crit_exit(); 1418 } 1419 1420 /* 1421 * Drain off all datagram fragments. 1422 */ 1423 void 1424 ip_drain(void) 1425 { 1426 int i; 1427 1428 for (i = 0; i < IPREASS_NHASH; i++) { 1429 while (ipq[i].next != &ipq[i]) { 1430 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1431 ip_freef(ipq[i].next); 1432 } 1433 } 1434 in_rtqdrain(); 1435 } 1436 1437 /* 1438 * Do option processing on a datagram, 1439 * possibly discarding it if bad options are encountered, 1440 * or forwarding it if source-routed. 1441 * The pass argument is used when operating in the IPSTEALTH 1442 * mode to tell what options to process: 1443 * [LS]SRR (pass 0) or the others (pass 1). 1444 * The reason for as many as two passes is that when doing IPSTEALTH, 1445 * non-routing options should be processed only if the packet is for us. 1446 * Returns 1 if packet has been forwarded/freed, 1447 * 0 if the packet should be processed further. 1448 */ 1449 static int 1450 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1451 { 1452 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1453 struct ip *ip = mtod(m, struct ip *); 1454 u_char *cp; 1455 struct in_ifaddr *ia; 1456 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1457 boolean_t forward = FALSE; 1458 struct in_addr *sin, dst; 1459 n_time ntime; 1460 1461 dst = ip->ip_dst; 1462 cp = (u_char *)(ip + 1); 1463 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1464 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1465 opt = cp[IPOPT_OPTVAL]; 1466 if (opt == IPOPT_EOL) 1467 break; 1468 if (opt == IPOPT_NOP) 1469 optlen = 1; 1470 else { 1471 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1472 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1473 goto bad; 1474 } 1475 optlen = cp[IPOPT_OLEN]; 1476 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1477 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1478 goto bad; 1479 } 1480 } 1481 switch (opt) { 1482 1483 default: 1484 break; 1485 1486 /* 1487 * Source routing with record. 1488 * Find interface with current destination address. 1489 * If none on this machine then drop if strictly routed, 1490 * or do nothing if loosely routed. 1491 * Record interface address and bring up next address 1492 * component. If strictly routed make sure next 1493 * address is on directly accessible net. 1494 */ 1495 case IPOPT_LSRR: 1496 case IPOPT_SSRR: 1497 if (ipstealth && pass > 0) 1498 break; 1499 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1500 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1501 goto bad; 1502 } 1503 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1504 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1505 goto bad; 1506 } 1507 ipaddr.sin_addr = ip->ip_dst; 1508 ia = (struct in_ifaddr *) 1509 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1510 if (ia == NULL) { 1511 if (opt == IPOPT_SSRR) { 1512 type = ICMP_UNREACH; 1513 code = ICMP_UNREACH_SRCFAIL; 1514 goto bad; 1515 } 1516 if (!ip_dosourceroute) 1517 goto nosourcerouting; 1518 /* 1519 * Loose routing, and not at next destination 1520 * yet; nothing to do except forward. 1521 */ 1522 break; 1523 } 1524 off--; /* 0 origin */ 1525 if (off > optlen - (int)sizeof(struct in_addr)) { 1526 /* 1527 * End of source route. Should be for us. 1528 */ 1529 if (!ip_acceptsourceroute) 1530 goto nosourcerouting; 1531 save_rte(cp, ip->ip_src); 1532 break; 1533 } 1534 if (ipstealth) 1535 goto dropit; 1536 if (!ip_dosourceroute) { 1537 if (ipforwarding) { 1538 char buf[sizeof "aaa.bbb.ccc.ddd"]; 1539 1540 /* 1541 * Acting as a router, so generate ICMP 1542 */ 1543 nosourcerouting: 1544 strcpy(buf, inet_ntoa(ip->ip_dst)); 1545 log(LOG_WARNING, 1546 "attempted source route from %s to %s\n", 1547 inet_ntoa(ip->ip_src), buf); 1548 type = ICMP_UNREACH; 1549 code = ICMP_UNREACH_SRCFAIL; 1550 goto bad; 1551 } else { 1552 /* 1553 * Not acting as a router, 1554 * so silently drop. 1555 */ 1556 dropit: 1557 ipstat.ips_cantforward++; 1558 m_freem(m); 1559 return (1); 1560 } 1561 } 1562 1563 /* 1564 * locate outgoing interface 1565 */ 1566 memcpy(&ipaddr.sin_addr, cp + off, 1567 sizeof ipaddr.sin_addr); 1568 1569 if (opt == IPOPT_SSRR) { 1570 #define INA struct in_ifaddr * 1571 #define SA struct sockaddr * 1572 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1573 == NULL) 1574 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1575 } else 1576 ia = ip_rtaddr(ipaddr.sin_addr, 1577 &ipforward_rt[mycpuid]); 1578 if (ia == NULL) { 1579 type = ICMP_UNREACH; 1580 code = ICMP_UNREACH_SRCFAIL; 1581 goto bad; 1582 } 1583 ip->ip_dst = ipaddr.sin_addr; 1584 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1585 sizeof(struct in_addr)); 1586 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1587 /* 1588 * Let ip_intr's mcast routing check handle mcast pkts 1589 */ 1590 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1591 break; 1592 1593 case IPOPT_RR: 1594 if (ipstealth && pass == 0) 1595 break; 1596 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1597 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1598 goto bad; 1599 } 1600 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1601 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1602 goto bad; 1603 } 1604 /* 1605 * If no space remains, ignore. 1606 */ 1607 off--; /* 0 origin */ 1608 if (off > optlen - (int)sizeof(struct in_addr)) 1609 break; 1610 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1611 sizeof ipaddr.sin_addr); 1612 /* 1613 * locate outgoing interface; if we're the destination, 1614 * use the incoming interface (should be same). 1615 */ 1616 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1617 (ia = ip_rtaddr(ipaddr.sin_addr, 1618 &ipforward_rt[mycpuid])) 1619 == NULL) { 1620 type = ICMP_UNREACH; 1621 code = ICMP_UNREACH_HOST; 1622 goto bad; 1623 } 1624 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1625 sizeof(struct in_addr)); 1626 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1627 break; 1628 1629 case IPOPT_TS: 1630 if (ipstealth && pass == 0) 1631 break; 1632 code = cp - (u_char *)ip; 1633 if (optlen < 4 || optlen > 40) { 1634 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1635 goto bad; 1636 } 1637 if ((off = cp[IPOPT_OFFSET]) < 5) { 1638 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1639 goto bad; 1640 } 1641 if (off > optlen - (int)sizeof(int32_t)) { 1642 cp[IPOPT_OFFSET + 1] += (1 << 4); 1643 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1644 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1645 goto bad; 1646 } 1647 break; 1648 } 1649 off--; /* 0 origin */ 1650 sin = (struct in_addr *)(cp + off); 1651 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1652 1653 case IPOPT_TS_TSONLY: 1654 break; 1655 1656 case IPOPT_TS_TSANDADDR: 1657 if (off + sizeof(n_time) + 1658 sizeof(struct in_addr) > optlen) { 1659 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1660 goto bad; 1661 } 1662 ipaddr.sin_addr = dst; 1663 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1664 m->m_pkthdr.rcvif); 1665 if (ia == NULL) 1666 continue; 1667 memcpy(sin, &IA_SIN(ia)->sin_addr, 1668 sizeof(struct in_addr)); 1669 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1670 off += sizeof(struct in_addr); 1671 break; 1672 1673 case IPOPT_TS_PRESPEC: 1674 if (off + sizeof(n_time) + 1675 sizeof(struct in_addr) > optlen) { 1676 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1677 goto bad; 1678 } 1679 memcpy(&ipaddr.sin_addr, sin, 1680 sizeof(struct in_addr)); 1681 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1682 continue; 1683 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1684 off += sizeof(struct in_addr); 1685 break; 1686 1687 default: 1688 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1689 goto bad; 1690 } 1691 ntime = iptime(); 1692 memcpy(cp + off, &ntime, sizeof(n_time)); 1693 cp[IPOPT_OFFSET] += sizeof(n_time); 1694 } 1695 } 1696 if (forward && ipforwarding) { 1697 ip_forward(m, TRUE, next_hop); 1698 return (1); 1699 } 1700 return (0); 1701 bad: 1702 icmp_error(m, type, code, 0, 0); 1703 ipstat.ips_badoptions++; 1704 return (1); 1705 } 1706 1707 /* 1708 * Given address of next destination (final or next hop), 1709 * return internet address info of interface to be used to get there. 1710 */ 1711 struct in_ifaddr * 1712 ip_rtaddr(struct in_addr dst, struct route *ro) 1713 { 1714 struct sockaddr_in *sin; 1715 1716 sin = (struct sockaddr_in *)&ro->ro_dst; 1717 1718 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1719 if (ro->ro_rt != NULL) { 1720 RTFREE(ro->ro_rt); 1721 ro->ro_rt = NULL; 1722 } 1723 sin->sin_family = AF_INET; 1724 sin->sin_len = sizeof *sin; 1725 sin->sin_addr = dst; 1726 rtalloc_ign(ro, RTF_PRCLONING); 1727 } 1728 1729 if (ro->ro_rt == NULL) 1730 return (NULL); 1731 1732 return (ifatoia(ro->ro_rt->rt_ifa)); 1733 } 1734 1735 /* 1736 * Save incoming source route for use in replies, 1737 * to be picked up later by ip_srcroute if the receiver is interested. 1738 */ 1739 void 1740 save_rte(u_char *option, struct in_addr dst) 1741 { 1742 unsigned olen; 1743 1744 olen = option[IPOPT_OLEN]; 1745 #ifdef DIAGNOSTIC 1746 if (ipprintfs) 1747 kprintf("save_rte: olen %d\n", olen); 1748 #endif 1749 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1750 return; 1751 bcopy(option, ip_srcrt.srcopt, olen); 1752 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1753 ip_srcrt.dst = dst; 1754 } 1755 1756 /* 1757 * Retrieve incoming source route for use in replies, 1758 * in the same form used by setsockopt. 1759 * The first hop is placed before the options, will be removed later. 1760 */ 1761 struct mbuf * 1762 ip_srcroute(void) 1763 { 1764 struct in_addr *p, *q; 1765 struct mbuf *m; 1766 1767 if (ip_nhops == 0) 1768 return (NULL); 1769 m = m_get(MB_DONTWAIT, MT_HEADER); 1770 if (m == NULL) 1771 return (NULL); 1772 1773 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1774 1775 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1776 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1777 OPTSIZ; 1778 #ifdef DIAGNOSTIC 1779 if (ipprintfs) 1780 kprintf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1781 #endif 1782 1783 /* 1784 * First save first hop for return route 1785 */ 1786 p = &ip_srcrt.route[ip_nhops - 1]; 1787 *(mtod(m, struct in_addr *)) = *p--; 1788 #ifdef DIAGNOSTIC 1789 if (ipprintfs) 1790 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1791 #endif 1792 1793 /* 1794 * Copy option fields and padding (nop) to mbuf. 1795 */ 1796 ip_srcrt.nop = IPOPT_NOP; 1797 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1798 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &ip_srcrt.nop, 1799 OPTSIZ); 1800 q = (struct in_addr *)(mtod(m, caddr_t) + 1801 sizeof(struct in_addr) + OPTSIZ); 1802 #undef OPTSIZ 1803 /* 1804 * Record return path as an IP source route, 1805 * reversing the path (pointers are now aligned). 1806 */ 1807 while (p >= ip_srcrt.route) { 1808 #ifdef DIAGNOSTIC 1809 if (ipprintfs) 1810 kprintf(" %x", ntohl(q->s_addr)); 1811 #endif 1812 *q++ = *p--; 1813 } 1814 /* 1815 * Last hop goes to final destination. 1816 */ 1817 *q = ip_srcrt.dst; 1818 #ifdef DIAGNOSTIC 1819 if (ipprintfs) 1820 kprintf(" %x\n", ntohl(q->s_addr)); 1821 #endif 1822 return (m); 1823 } 1824 1825 /* 1826 * Strip out IP options. 1827 */ 1828 void 1829 ip_stripoptions(struct mbuf *m) 1830 { 1831 int datalen; 1832 struct ip *ip = mtod(m, struct ip *); 1833 caddr_t opts; 1834 int optlen; 1835 1836 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1837 opts = (caddr_t)(ip + 1); 1838 datalen = m->m_len - (sizeof(struct ip) + optlen); 1839 bcopy(opts + optlen, opts, datalen); 1840 m->m_len -= optlen; 1841 if (m->m_flags & M_PKTHDR) 1842 m->m_pkthdr.len -= optlen; 1843 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1844 } 1845 1846 u_char inetctlerrmap[PRC_NCMDS] = { 1847 0, 0, 0, 0, 1848 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1849 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1850 EMSGSIZE, EHOSTUNREACH, 0, 0, 1851 0, 0, 0, 0, 1852 ENOPROTOOPT, ECONNREFUSED 1853 }; 1854 1855 /* 1856 * Forward a packet. If some error occurs return the sender 1857 * an icmp packet. Note we can't always generate a meaningful 1858 * icmp message because icmp doesn't have a large enough repertoire 1859 * of codes and types. 1860 * 1861 * If not forwarding, just drop the packet. This could be confusing 1862 * if ipforwarding was zero but some routing protocol was advancing 1863 * us as a gateway to somewhere. However, we must let the routing 1864 * protocol deal with that. 1865 * 1866 * The using_srcrt parameter indicates whether the packet is being forwarded 1867 * via a source route. 1868 */ 1869 static void 1870 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop) 1871 { 1872 struct ip *ip = mtod(m, struct ip *); 1873 struct sockaddr_in *ipforward_rtaddr; 1874 struct rtentry *rt; 1875 int error, type = 0, code = 0, destmtu = 0; 1876 struct mbuf *mcopy; 1877 n_long dest; 1878 struct in_addr pkt_dst; 1879 struct m_hdr tag; 1880 struct route *cache_rt = &ipforward_rt[mycpuid]; 1881 1882 dest = INADDR_ANY; 1883 /* 1884 * Cache the destination address of the packet; this may be 1885 * changed by use of 'ipfw fwd'. 1886 */ 1887 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 1888 1889 #ifdef DIAGNOSTIC 1890 if (ipprintfs) 1891 kprintf("forward: src %x dst %x ttl %x\n", 1892 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1893 #endif 1894 1895 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1896 ipstat.ips_cantforward++; 1897 m_freem(m); 1898 return; 1899 } 1900 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1901 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1902 return; 1903 } 1904 1905 ipforward_rtaddr = (struct sockaddr_in *) &cache_rt->ro_dst; 1906 if (cache_rt->ro_rt == NULL || 1907 ipforward_rtaddr->sin_addr.s_addr != pkt_dst.s_addr) { 1908 if (cache_rt->ro_rt != NULL) { 1909 RTFREE(cache_rt->ro_rt); 1910 cache_rt->ro_rt = NULL; 1911 } 1912 ipforward_rtaddr->sin_family = AF_INET; 1913 ipforward_rtaddr->sin_len = sizeof(struct sockaddr_in); 1914 ipforward_rtaddr->sin_addr = pkt_dst; 1915 rtalloc_ign(cache_rt, RTF_PRCLONING); 1916 if (cache_rt->ro_rt == NULL) { 1917 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1918 return; 1919 } 1920 } 1921 rt = cache_rt->ro_rt; 1922 1923 /* 1924 * Save the IP header and at most 8 bytes of the payload, 1925 * in case we need to generate an ICMP message to the src. 1926 * 1927 * XXX this can be optimized a lot by saving the data in a local 1928 * buffer on the stack (72 bytes at most), and only allocating the 1929 * mbuf if really necessary. The vast majority of the packets 1930 * are forwarded without having to send an ICMP back (either 1931 * because unnecessary, or because rate limited), so we are 1932 * really we are wasting a lot of work here. 1933 * 1934 * We don't use m_copy() because it might return a reference 1935 * to a shared cluster. Both this function and ip_output() 1936 * assume exclusive access to the IP header in `m', so any 1937 * data in a cluster may change before we reach icmp_error(). 1938 */ 1939 MGETHDR(mcopy, MB_DONTWAIT, m->m_type); 1940 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) { 1941 /* 1942 * It's probably ok if the pkthdr dup fails (because 1943 * the deep copy of the tag chain failed), but for now 1944 * be conservative and just discard the copy since 1945 * code below may some day want the tags. 1946 */ 1947 m_free(mcopy); 1948 mcopy = NULL; 1949 } 1950 if (mcopy != NULL) { 1951 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1952 (int)ip->ip_len); 1953 mcopy->m_pkthdr.len = mcopy->m_len; 1954 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1955 } 1956 1957 if (!ipstealth) 1958 ip->ip_ttl -= IPTTLDEC; 1959 1960 /* 1961 * If forwarding packet using same interface that it came in on, 1962 * perhaps should send a redirect to sender to shortcut a hop. 1963 * Only send redirect if source is sending directly to us, 1964 * and if packet was not source routed (or has any options). 1965 * Also, don't send redirect if forwarding using a default route 1966 * or a route modified by a redirect. 1967 */ 1968 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1969 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1970 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1971 ipsendredirects && !using_srcrt && next_hop == NULL) { 1972 u_long src = ntohl(ip->ip_src.s_addr); 1973 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa; 1974 1975 if (rt_ifa != NULL && 1976 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) { 1977 if (rt->rt_flags & RTF_GATEWAY) 1978 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1979 else 1980 dest = pkt_dst.s_addr; 1981 /* 1982 * Router requirements says to only send 1983 * host redirects. 1984 */ 1985 type = ICMP_REDIRECT; 1986 code = ICMP_REDIRECT_HOST; 1987 #ifdef DIAGNOSTIC 1988 if (ipprintfs) 1989 kprintf("redirect (%d) to %x\n", code, dest); 1990 #endif 1991 } 1992 } 1993 1994 if (next_hop != NULL) { 1995 /* Pass IPFORWARD info if available */ 1996 tag.mh_type = MT_TAG; 1997 tag.mh_flags = PACKET_TAG_IPFORWARD; 1998 tag.mh_data = (caddr_t)next_hop; 1999 tag.mh_next = m; 2000 m = (struct mbuf *)&tag; 2001 } 2002 2003 error = ip_output(m, NULL, cache_rt, IP_FORWARDING, NULL, 2004 NULL); 2005 if (error == 0) { 2006 ipstat.ips_forward++; 2007 if (type == 0) { 2008 if (mcopy) { 2009 /* ipflow_create() will free mcopy */ 2010 ipflow_create(cache_rt, mcopy); 2011 } 2012 return; /* most common case */ 2013 } else { 2014 ipstat.ips_redirectsent++; 2015 } 2016 } else { 2017 ipstat.ips_cantforward++; 2018 } 2019 2020 if (mcopy == NULL) 2021 return; 2022 2023 /* 2024 * Send ICMP message. 2025 */ 2026 2027 switch (error) { 2028 2029 case 0: /* forwarded, but need redirect */ 2030 /* type, code set above */ 2031 break; 2032 2033 case ENETUNREACH: /* shouldn't happen, checked above */ 2034 case EHOSTUNREACH: 2035 case ENETDOWN: 2036 case EHOSTDOWN: 2037 default: 2038 type = ICMP_UNREACH; 2039 code = ICMP_UNREACH_HOST; 2040 break; 2041 2042 case EMSGSIZE: 2043 type = ICMP_UNREACH; 2044 code = ICMP_UNREACH_NEEDFRAG; 2045 #ifdef IPSEC 2046 /* 2047 * If the packet is routed over IPsec tunnel, tell the 2048 * originator the tunnel MTU. 2049 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2050 * XXX quickhack!!! 2051 */ 2052 if (cache_rt->ro_rt != NULL) { 2053 struct secpolicy *sp = NULL; 2054 int ipsecerror; 2055 int ipsechdr; 2056 struct route *ro; 2057 2058 sp = ipsec4_getpolicybyaddr(mcopy, 2059 IPSEC_DIR_OUTBOUND, 2060 IP_FORWARDING, 2061 &ipsecerror); 2062 2063 if (sp == NULL) 2064 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2065 else { 2066 /* count IPsec header size */ 2067 ipsechdr = ipsec4_hdrsiz(mcopy, 2068 IPSEC_DIR_OUTBOUND, 2069 NULL); 2070 2071 /* 2072 * find the correct route for outer IPv4 2073 * header, compute tunnel MTU. 2074 * 2075 */ 2076 if (sp->req != NULL && sp->req->sav != NULL && 2077 sp->req->sav->sah != NULL) { 2078 ro = &sp->req->sav->sah->sa_route; 2079 if (ro->ro_rt != NULL && 2080 ro->ro_rt->rt_ifp != NULL) { 2081 destmtu = 2082 ro->ro_rt->rt_ifp->if_mtu; 2083 destmtu -= ipsechdr; 2084 } 2085 } 2086 2087 key_freesp(sp); 2088 } 2089 } 2090 #elif FAST_IPSEC 2091 /* 2092 * If the packet is routed over IPsec tunnel, tell the 2093 * originator the tunnel MTU. 2094 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2095 * XXX quickhack!!! 2096 */ 2097 if (cache_rt->ro_rt != NULL) { 2098 struct secpolicy *sp = NULL; 2099 int ipsecerror; 2100 int ipsechdr; 2101 struct route *ro; 2102 2103 sp = ipsec_getpolicybyaddr(mcopy, 2104 IPSEC_DIR_OUTBOUND, 2105 IP_FORWARDING, 2106 &ipsecerror); 2107 2108 if (sp == NULL) 2109 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2110 else { 2111 /* count IPsec header size */ 2112 ipsechdr = ipsec4_hdrsiz(mcopy, 2113 IPSEC_DIR_OUTBOUND, 2114 NULL); 2115 2116 /* 2117 * find the correct route for outer IPv4 2118 * header, compute tunnel MTU. 2119 */ 2120 2121 if (sp->req != NULL && 2122 sp->req->sav != NULL && 2123 sp->req->sav->sah != NULL) { 2124 ro = &sp->req->sav->sah->sa_route; 2125 if (ro->ro_rt != NULL && 2126 ro->ro_rt->rt_ifp != NULL) { 2127 destmtu = 2128 ro->ro_rt->rt_ifp->if_mtu; 2129 destmtu -= ipsechdr; 2130 } 2131 } 2132 2133 KEY_FREESP(&sp); 2134 } 2135 } 2136 #else /* !IPSEC && !FAST_IPSEC */ 2137 if (cache_rt->ro_rt != NULL) 2138 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2139 #endif /*IPSEC*/ 2140 ipstat.ips_cantfrag++; 2141 break; 2142 2143 case ENOBUFS: 2144 /* 2145 * A router should not generate ICMP_SOURCEQUENCH as 2146 * required in RFC1812 Requirements for IP Version 4 Routers. 2147 * Source quench could be a big problem under DoS attacks, 2148 * or if the underlying interface is rate-limited. 2149 * Those who need source quench packets may re-enable them 2150 * via the net.inet.ip.sendsourcequench sysctl. 2151 */ 2152 if (!ip_sendsourcequench) { 2153 m_freem(mcopy); 2154 return; 2155 } else { 2156 type = ICMP_SOURCEQUENCH; 2157 code = 0; 2158 } 2159 break; 2160 2161 case EACCES: /* ipfw denied packet */ 2162 m_freem(mcopy); 2163 return; 2164 } 2165 icmp_error(mcopy, type, code, dest, destmtu); 2166 } 2167 2168 void 2169 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2170 struct mbuf *m) 2171 { 2172 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2173 struct timeval tv; 2174 2175 microtime(&tv); 2176 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2177 SCM_TIMESTAMP, SOL_SOCKET); 2178 if (*mp) 2179 mp = &(*mp)->m_next; 2180 } 2181 if (inp->inp_flags & INP_RECVDSTADDR) { 2182 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2183 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2184 if (*mp) 2185 mp = &(*mp)->m_next; 2186 } 2187 if (inp->inp_flags & INP_RECVTTL) { 2188 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2189 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2190 if (*mp) 2191 mp = &(*mp)->m_next; 2192 } 2193 #ifdef notyet 2194 /* XXX 2195 * Moving these out of udp_input() made them even more broken 2196 * than they already were. 2197 */ 2198 /* options were tossed already */ 2199 if (inp->inp_flags & INP_RECVOPTS) { 2200 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2201 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2202 if (*mp) 2203 mp = &(*mp)->m_next; 2204 } 2205 /* ip_srcroute doesn't do what we want here, need to fix */ 2206 if (inp->inp_flags & INP_RECVRETOPTS) { 2207 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2208 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2209 if (*mp) 2210 mp = &(*mp)->m_next; 2211 } 2212 #endif 2213 if (inp->inp_flags & INP_RECVIF) { 2214 struct ifnet *ifp; 2215 struct sdlbuf { 2216 struct sockaddr_dl sdl; 2217 u_char pad[32]; 2218 } sdlbuf; 2219 struct sockaddr_dl *sdp; 2220 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2221 2222 if (((ifp = m->m_pkthdr.rcvif)) && 2223 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2224 sdp = IF_LLSOCKADDR(ifp); 2225 /* 2226 * Change our mind and don't try copy. 2227 */ 2228 if ((sdp->sdl_family != AF_LINK) || 2229 (sdp->sdl_len > sizeof(sdlbuf))) { 2230 goto makedummy; 2231 } 2232 bcopy(sdp, sdl2, sdp->sdl_len); 2233 } else { 2234 makedummy: 2235 sdl2->sdl_len = 2236 offsetof(struct sockaddr_dl, sdl_data[0]); 2237 sdl2->sdl_family = AF_LINK; 2238 sdl2->sdl_index = 0; 2239 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2240 } 2241 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2242 IP_RECVIF, IPPROTO_IP); 2243 if (*mp) 2244 mp = &(*mp)->m_next; 2245 } 2246 } 2247 2248 /* 2249 * XXX these routines are called from the upper part of the kernel. 2250 * 2251 * They could also be moved to ip_mroute.c, since all the RSVP 2252 * handling is done there already. 2253 */ 2254 int 2255 ip_rsvp_init(struct socket *so) 2256 { 2257 if (so->so_type != SOCK_RAW || 2258 so->so_proto->pr_protocol != IPPROTO_RSVP) 2259 return EOPNOTSUPP; 2260 2261 if (ip_rsvpd != NULL) 2262 return EADDRINUSE; 2263 2264 ip_rsvpd = so; 2265 /* 2266 * This may seem silly, but we need to be sure we don't over-increment 2267 * the RSVP counter, in case something slips up. 2268 */ 2269 if (!ip_rsvp_on) { 2270 ip_rsvp_on = 1; 2271 rsvp_on++; 2272 } 2273 2274 return 0; 2275 } 2276 2277 int 2278 ip_rsvp_done(void) 2279 { 2280 ip_rsvpd = NULL; 2281 /* 2282 * This may seem silly, but we need to be sure we don't over-decrement 2283 * the RSVP counter, in case something slips up. 2284 */ 2285 if (ip_rsvp_on) { 2286 ip_rsvp_on = 0; 2287 rsvp_on--; 2288 } 2289 return 0; 2290 } 2291 2292 void 2293 rsvp_input(struct mbuf *m, ...) /* XXX must fixup manually */ 2294 { 2295 int off, proto; 2296 __va_list ap; 2297 2298 __va_start(ap, m); 2299 off = __va_arg(ap, int); 2300 proto = __va_arg(ap, int); 2301 __va_end(ap); 2302 2303 if (rsvp_input_p) { /* call the real one if loaded */ 2304 rsvp_input_p(m, off, proto); 2305 return; 2306 } 2307 2308 /* Can still get packets with rsvp_on = 0 if there is a local member 2309 * of the group to which the RSVP packet is addressed. But in this 2310 * case we want to throw the packet away. 2311 */ 2312 2313 if (!rsvp_on) { 2314 m_freem(m); 2315 return; 2316 } 2317 2318 if (ip_rsvpd != NULL) { 2319 rip_input(m, off, proto); 2320 return; 2321 } 2322 /* Drop the packet */ 2323 m_freem(m); 2324 } 2325