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 1.82 2008/07/03 08:22:36 corecode 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_ifaddrheads[MAXCPU]; /* first inet address */ 209 struct in_ifaddrhashhead *in_ifaddrhashtbls[MAXCPU]; 210 /* inet addr hash table */ 211 u_long in_ifaddrhmask; /* mask for hash table */ 212 213 struct ip_stats ipstats_percpu[MAXCPU]; 214 #ifdef SMP 215 static int 216 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 217 { 218 int cpu, error = 0; 219 220 for (cpu = 0; cpu < ncpus; ++cpu) { 221 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu], 222 sizeof(struct ip_stats)))) 223 break; 224 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu], 225 sizeof(struct ip_stats)))) 226 break; 227 } 228 229 return (error); 230 } 231 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 232 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 233 #else 234 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 235 &ipstat, ip_stats, "IP statistics"); 236 #endif 237 238 /* Packet reassembly stuff */ 239 #define IPREASS_NHASH_LOG2 6 240 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 241 #define IPREASS_HMASK (IPREASS_NHASH - 1) 242 #define IPREASS_HASH(x,y) \ 243 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 244 245 static struct ipq ipq[IPREASS_NHASH]; 246 247 #ifdef IPCTL_DEFMTU 248 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 249 &ip_mtu, 0, "Default MTU"); 250 #endif 251 252 #ifdef IPSTEALTH 253 static int ipstealth = 0; 254 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, ""); 255 #else 256 static const int ipstealth = 0; 257 #endif 258 259 260 /* Firewall hooks */ 261 ip_fw_chk_t *ip_fw_chk_ptr; 262 ip_fw_dn_io_t *ip_fw_dn_io_ptr; 263 int fw_enable = 1; 264 int fw_one_pass = 1; 265 266 struct pfil_head inet_pfil_hook; 267 268 /* 269 * XXX this is ugly -- the following two global variables are 270 * used to store packet state while it travels through the stack. 271 * Note that the code even makes assumptions on the size and 272 * alignment of fields inside struct ip_srcrt so e.g. adding some 273 * fields will break the code. This needs to be fixed. 274 * 275 * We need to save the IP options in case a protocol wants to respond 276 * to an incoming packet over the same route if the packet got here 277 * using IP source routing. This allows connection establishment and 278 * maintenance when the remote end is on a network that is not known 279 * to us. 280 */ 281 static int ip_nhops = 0; 282 283 static struct ip_srcrt { 284 struct in_addr dst; /* final destination */ 285 char nop; /* one NOP to align */ 286 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 287 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 288 } ip_srcrt; 289 290 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 291 static struct malloc_pipe ipq_mpipe; 292 293 static void save_rte (u_char *, struct in_addr); 294 static int ip_dooptions (struct mbuf *m, int, 295 struct sockaddr_in *next_hop); 296 static void ip_freef (struct ipq *); 297 static void ip_input_handler (struct netmsg *); 298 static struct mbuf *ip_reass (struct mbuf *, struct ipq *, 299 struct ipq *, u_int32_t *); 300 301 /* 302 * IP initialization: fill in IP protocol switch table. 303 * All protocols not implemented in kernel go to raw IP protocol handler. 304 */ 305 void 306 ip_init(void) 307 { 308 struct protosw *pr; 309 int i; 310 #ifdef SMP 311 int cpu; 312 #endif 313 314 /* 315 * Make sure we can handle a reasonable number of fragments but 316 * cap it at 4000 (XXX). 317 */ 318 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 319 IFQ_MAXLEN, 4000, 0, NULL); 320 for (i = 0; i < ncpus; ++i) { 321 TAILQ_INIT(&in_ifaddrheads[i]); 322 in_ifaddrhashtbls[i] = 323 hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 324 } 325 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 326 if (pr == NULL) 327 panic("ip_init"); 328 for (i = 0; i < IPPROTO_MAX; i++) 329 ip_protox[i] = pr - inetsw; 330 for (pr = inetdomain.dom_protosw; 331 pr < inetdomain.dom_protoswNPROTOSW; pr++) 332 if (pr->pr_domain->dom_family == PF_INET && 333 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 334 ip_protox[pr->pr_protocol] = pr - inetsw; 335 336 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 337 inet_pfil_hook.ph_af = AF_INET; 338 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) { 339 kprintf("%s: WARNING: unable to register pfil hook, " 340 "error %d\n", __func__, i); 341 } 342 343 for (i = 0; i < IPREASS_NHASH; i++) 344 ipq[i].next = ipq[i].prev = &ipq[i]; 345 346 maxnipq = nmbclusters / 32; 347 maxfragsperpacket = 16; 348 349 ip_id = time_second & 0xffff; 350 351 /* 352 * Initialize IP statistics counters for each CPU. 353 * 354 */ 355 #ifdef SMP 356 for (cpu = 0; cpu < ncpus; ++cpu) { 357 bzero(&ipstats_percpu[cpu], sizeof(struct ip_stats)); 358 } 359 #else 360 bzero(&ipstat, sizeof(struct ip_stats)); 361 #endif 362 363 netisr_register(NETISR_IP, ip_mport_in, ip_input_handler); 364 } 365 366 /* 367 * XXX watch out this one. It is perhaps used as a cache for 368 * the most recently used route ? it is cleared in in_addroute() 369 * when a new route is successfully created. 370 */ 371 struct route ipforward_rt[MAXCPU]; 372 373 /* Do transport protocol processing. */ 374 static void 375 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip, 376 struct sockaddr_in *nexthop) 377 { 378 /* 379 * Switch out to protocol's input routine. 380 */ 381 if (nexthop && ip->ip_p == IPPROTO_TCP) { 382 /* TCP needs IPFORWARD info if available */ 383 struct m_hdr tag; 384 385 tag.mh_type = MT_TAG; 386 tag.mh_flags = PACKET_TAG_IPFORWARD; 387 tag.mh_data = (caddr_t)nexthop; 388 tag.mh_next = m; 389 390 (*inetsw[ip_protox[ip->ip_p]].pr_input) 391 ((struct mbuf *)&tag, hlen, ip->ip_p); 392 } else { 393 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, ip->ip_p); 394 } 395 } 396 397 struct netmsg_transport_packet { 398 struct netmsg nm_netmsg; 399 struct mbuf *nm_mbuf; 400 int nm_hlen; 401 boolean_t nm_hasnexthop; 402 struct sockaddr_in nm_nexthop; 403 }; 404 405 static void 406 transport_processing_handler(netmsg_t netmsg) 407 { 408 struct netmsg_transport_packet *msg = (void *)netmsg; 409 struct sockaddr_in *nexthop; 410 struct ip *ip; 411 412 ip = mtod(msg->nm_mbuf, struct ip *); 413 nexthop = msg->nm_hasnexthop ? &msg->nm_nexthop : NULL; 414 transport_processing_oncpu(msg->nm_mbuf, msg->nm_hlen, ip, nexthop); 415 lwkt_replymsg(&msg->nm_netmsg.nm_lmsg, 0); 416 } 417 418 static void 419 ip_input_handler(struct netmsg *msg0) 420 { 421 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet; 422 423 ip_input(m); 424 /* msg0 was embedded in the mbuf, do not reply! */ 425 } 426 427 /* 428 * IP input routine. Checksum and byte swap header. If fragmented 429 * try to reassemble. Process options. Pass to next level. 430 */ 431 void 432 ip_input(struct mbuf *m) 433 { 434 struct ip *ip; 435 struct ipq *fp; 436 struct in_ifaddr *ia = NULL; 437 struct in_ifaddr_container *iac; 438 int i, hlen, checkif; 439 u_short sum; 440 struct in_addr pkt_dst; 441 u_int32_t divert_info = 0; /* packet divert/tee info */ 442 struct ip_fw_args args; 443 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 444 boolean_t needredispatch = FALSE; 445 struct in_addr odst; /* original dst address(NAT) */ 446 struct m_tag *mtag; 447 #ifdef FAST_IPSEC 448 struct tdb_ident *tdbi; 449 struct secpolicy *sp; 450 int error; 451 #endif 452 453 args.eh = NULL; 454 args.oif = NULL; 455 args.rule = NULL; 456 args.next_hop = NULL; 457 458 /* Grab info from MT_TAG mbufs prepended to the chain. */ 459 while (m != NULL && m->m_type == MT_TAG) { 460 switch(m->_m_tag_id) { 461 case PACKET_TAG_IPFORWARD: 462 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 463 break; 464 default: 465 kprintf("ip_input: unrecognised MT_TAG tag %d\n", 466 m->_m_tag_id); 467 break; 468 } 469 m = m->m_next; 470 } 471 M_ASSERTPKTHDR(m); 472 473 /* Extract info from dummynet tag */ 474 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL); 475 if (mtag != NULL) { 476 args.rule = ((struct dn_pkt *)m_tag_data(mtag))->dn_priv; 477 478 m_tag_delete(m, mtag); 479 mtag = NULL; 480 } 481 482 if (args.rule != NULL) { /* dummynet already filtered us */ 483 ip = mtod(m, struct ip *); 484 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 485 goto iphack; 486 } 487 488 ipstat.ips_total++; 489 490 /* length checks already done in ip_demux() */ 491 KASSERT(m->m_len >= sizeof(ip), ("IP header not in one mbuf")); 492 493 ip = mtod(m, struct ip *); 494 495 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 496 ipstat.ips_badvers++; 497 goto bad; 498 } 499 500 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 501 /* length checks already done in ip_demux() */ 502 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 503 KASSERT(m->m_len >= hlen, ("packet shorter than IP header length")); 504 505 /* 127/8 must not appear on wire - RFC1122 */ 506 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 507 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 508 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 509 ipstat.ips_badaddr++; 510 goto bad; 511 } 512 } 513 514 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 515 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 516 } else { 517 if (hlen == sizeof(struct ip)) { 518 sum = in_cksum_hdr(ip); 519 } else { 520 sum = in_cksum(m, hlen); 521 } 522 } 523 if (sum != 0) { 524 ipstat.ips_badsum++; 525 goto bad; 526 } 527 528 #ifdef ALTQ 529 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 530 /* packet is dropped by traffic conditioner */ 531 return; 532 } 533 #endif 534 /* 535 * Convert fields to host representation. 536 */ 537 ip->ip_len = ntohs(ip->ip_len); 538 if (ip->ip_len < hlen) { 539 ipstat.ips_badlen++; 540 goto bad; 541 } 542 ip->ip_off = ntohs(ip->ip_off); 543 544 /* 545 * Check that the amount of data in the buffers 546 * is as at least much as the IP header would have us expect. 547 * Trim mbufs if longer than we expect. 548 * Drop packet if shorter than we expect. 549 */ 550 if (m->m_pkthdr.len < ip->ip_len) { 551 ipstat.ips_tooshort++; 552 goto bad; 553 } 554 if (m->m_pkthdr.len > ip->ip_len) { 555 if (m->m_len == m->m_pkthdr.len) { 556 m->m_len = ip->ip_len; 557 m->m_pkthdr.len = ip->ip_len; 558 } else 559 m_adj(m, ip->ip_len - m->m_pkthdr.len); 560 } 561 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 562 /* 563 * Bypass packet filtering for packets from a tunnel (gif). 564 */ 565 if (ipsec_gethist(m, NULL)) 566 goto pass; 567 #endif 568 569 /* 570 * IpHack's section. 571 * Right now when no processing on packet has done 572 * and it is still fresh out of network we do our black 573 * deals with it. 574 * - Firewall: deny/allow/divert 575 * - Xlate: translate packet's addr/port (NAT). 576 * - Pipe: pass pkt through dummynet. 577 * - Wrap: fake packet's addr/port <unimpl.> 578 * - Encapsulate: put it in another IP and send out. <unimp.> 579 */ 580 581 iphack: 582 583 /* 584 * Run through list of hooks for input packets. 585 * 586 * NB: Beware of the destination address changing (e.g. 587 * by NAT rewriting). When this happens, tell 588 * ip_forward to do the right thing. 589 */ 590 if (pfil_has_hooks(&inet_pfil_hook)) { 591 odst = ip->ip_dst; 592 if (pfil_run_hooks(&inet_pfil_hook, &m, 593 m->m_pkthdr.rcvif, PFIL_IN)) { 594 return; 595 } 596 if (m == NULL) /* consumed by filter */ 597 return; 598 ip = mtod(m, struct ip *); 599 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 600 } 601 602 if (fw_enable && IPFW_LOADED) { 603 /* 604 * If we've been forwarded from the output side, then 605 * skip the firewall a second time 606 */ 607 if (args.next_hop != NULL) 608 goto ours; 609 610 args.m = m; 611 i = ip_fw_chk_ptr(&args); 612 m = args.m; 613 614 if ((i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 615 if (m != NULL) 616 m_freem(m); 617 return; 618 } 619 ip = mtod(m, struct ip *); /* just in case m changed */ 620 if (i == 0 && args.next_hop == NULL) /* common case */ 621 goto pass; 622 if (i & IP_FW_PORT_DYNT_FLAG) { 623 /* Send packet to the appropriate pipe */ 624 ip_fw_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 625 return; 626 } 627 #ifdef IPDIVERT 628 if (i != 0 && !(i & IP_FW_PORT_DYNT_FLAG)) { 629 /* Divert or tee packet */ 630 divert_info = i; 631 goto ours; 632 } 633 #endif 634 if (i == 0 && args.next_hop != NULL) 635 goto pass; 636 /* 637 * if we get here, the packet must be dropped 638 */ 639 m_freem(m); 640 return; 641 } 642 pass: 643 644 /* 645 * Process options and, if not destined for us, 646 * ship it on. ip_dooptions returns 1 when an 647 * error was detected (causing an icmp message 648 * to be sent and the original packet to be freed). 649 */ 650 ip_nhops = 0; /* for source routed packets */ 651 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, args.next_hop)) 652 return; 653 654 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 655 * matter if it is destined to another node, or whether it is 656 * a multicast one, RSVP wants it! and prevents it from being forwarded 657 * anywhere else. Also checks if the rsvp daemon is running before 658 * grabbing the packet. 659 */ 660 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 661 goto ours; 662 663 /* 664 * Check our list of addresses, to see if the packet is for us. 665 * If we don't have any addresses, assume any unicast packet 666 * we receive might be for us (and let the upper layers deal 667 * with it). 668 */ 669 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) && 670 !(m->m_flags & (M_MCAST | M_BCAST))) 671 goto ours; 672 673 /* 674 * Cache the destination address of the packet; this may be 675 * changed by use of 'ipfw fwd'. 676 */ 677 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 678 679 /* 680 * Enable a consistency check between the destination address 681 * and the arrival interface for a unicast packet (the RFC 1122 682 * strong ES model) if IP forwarding is disabled and the packet 683 * is not locally generated and the packet is not subject to 684 * 'ipfw fwd'. 685 * 686 * XXX - Checking also should be disabled if the destination 687 * address is ipnat'ed to a different interface. 688 * 689 * XXX - Checking is incompatible with IP aliases added 690 * to the loopback interface instead of the interface where 691 * the packets are received. 692 */ 693 checkif = ip_checkinterface && 694 !ipforwarding && 695 m->m_pkthdr.rcvif != NULL && 696 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 697 (args.next_hop == NULL); 698 699 /* 700 * Check for exact addresses in the hash bucket. 701 */ 702 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 703 ia = iac->ia; 704 705 /* 706 * If the address matches, verify that the packet 707 * arrived via the correct interface if checking is 708 * enabled. 709 */ 710 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 711 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 712 goto ours; 713 } 714 ia = NULL; 715 716 /* 717 * Check for broadcast addresses. 718 * 719 * Only accept broadcast packets that arrive via the matching 720 * interface. Reception of forwarded directed broadcasts would 721 * be handled via ip_forward() and ether_output() with the loopback 722 * into the stack for SIMPLEX interfaces handled by ether_output(). 723 */ 724 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 725 struct ifaddr_container *ifac; 726 727 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 728 ifa_link) { 729 struct ifaddr *ifa = ifac->ifa; 730 731 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 732 continue; 733 if (ifa->ifa_addr->sa_family != AF_INET) 734 continue; 735 ia = ifatoia(ifa); 736 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 737 pkt_dst.s_addr) 738 goto ours; 739 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 740 goto ours; 741 #ifdef BOOTP_COMPAT 742 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 743 goto ours; 744 #endif 745 } 746 } 747 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 748 struct in_multi *inm; 749 750 if (ip_mrouter != NULL) { 751 /* 752 * If we are acting as a multicast router, all 753 * incoming multicast packets are passed to the 754 * kernel-level multicast forwarding function. 755 * The packet is returned (relatively) intact; if 756 * ip_mforward() returns a non-zero value, the packet 757 * must be discarded, else it may be accepted below. 758 */ 759 if (ip_mforward != NULL && 760 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 761 ipstat.ips_cantforward++; 762 m_freem(m); 763 return; 764 } 765 766 /* 767 * The process-level routing daemon needs to receive 768 * all multicast IGMP packets, whether or not this 769 * host belongs to their destination groups. 770 */ 771 if (ip->ip_p == IPPROTO_IGMP) 772 goto ours; 773 ipstat.ips_forward++; 774 } 775 /* 776 * See if we belong to the destination multicast group on the 777 * arrival interface. 778 */ 779 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 780 if (inm == NULL) { 781 ipstat.ips_notmember++; 782 m_freem(m); 783 return; 784 } 785 goto ours; 786 } 787 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 788 goto ours; 789 if (ip->ip_dst.s_addr == INADDR_ANY) 790 goto ours; 791 792 /* 793 * FAITH(Firewall Aided Internet Translator) 794 */ 795 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 796 if (ip_keepfaith) { 797 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 798 goto ours; 799 } 800 m_freem(m); 801 return; 802 } 803 804 /* 805 * Not for us; forward if possible and desirable. 806 */ 807 if (!ipforwarding) { 808 ipstat.ips_cantforward++; 809 m_freem(m); 810 } else { 811 #ifdef IPSEC 812 /* 813 * Enforce inbound IPsec SPD. 814 */ 815 if (ipsec4_in_reject(m, NULL)) { 816 ipsecstat.in_polvio++; 817 goto bad; 818 } 819 #endif 820 #ifdef FAST_IPSEC 821 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 822 crit_enter(); 823 if (mtag != NULL) { 824 tdbi = (struct tdb_ident *)m_tag_data(mtag); 825 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 826 } else { 827 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 828 IP_FORWARDING, &error); 829 } 830 if (sp == NULL) { /* NB: can happen if error */ 831 crit_exit(); 832 /*XXX error stat???*/ 833 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 834 goto bad; 835 } 836 837 /* 838 * Check security policy against packet attributes. 839 */ 840 error = ipsec_in_reject(sp, m); 841 KEY_FREESP(&sp); 842 crit_exit(); 843 if (error) { 844 ipstat.ips_cantforward++; 845 goto bad; 846 } 847 #endif 848 ip_forward(m, using_srcrt, args.next_hop); 849 } 850 return; 851 852 ours: 853 854 /* 855 * IPSTEALTH: Process non-routing options only 856 * if the packet is destined for us. 857 */ 858 if (ipstealth && 859 hlen > sizeof(struct ip) && 860 ip_dooptions(m, 1, args.next_hop)) 861 return; 862 863 /* Count the packet in the ip address stats */ 864 if (ia != NULL) { 865 ia->ia_ifa.if_ipackets++; 866 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 867 } 868 869 /* 870 * If offset or IP_MF are set, must reassemble. 871 * Otherwise, nothing need be done. 872 * (We could look in the reassembly queue to see 873 * if the packet was previously fragmented, 874 * but it's not worth the time; just let them time out.) 875 */ 876 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 877 878 /* If maxnipq is 0, never accept fragments. */ 879 if (maxnipq == 0) { 880 ipstat.ips_fragments++; 881 ipstat.ips_fragdropped++; 882 goto bad; 883 } 884 885 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 886 /* 887 * Look for queue of fragments 888 * of this datagram. 889 */ 890 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 891 if (ip->ip_id == fp->ipq_id && 892 ip->ip_src.s_addr == fp->ipq_src.s_addr && 893 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 894 ip->ip_p == fp->ipq_p) 895 goto found; 896 897 fp = NULL; 898 899 /* 900 * Enforce upper bound on number of fragmented packets 901 * for which we attempt reassembly; 902 * If maxnipq is -1, accept all fragments without limitation. 903 */ 904 if ((nipq > maxnipq) && (maxnipq > 0)) { 905 /* 906 * drop something from the tail of the current queue 907 * before proceeding further 908 */ 909 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 910 for (i = 0; i < IPREASS_NHASH; i++) { 911 if (ipq[i].prev != &ipq[i]) { 912 ipstat.ips_fragtimeout += 913 ipq[i].prev->ipq_nfrags; 914 ip_freef(ipq[i].prev); 915 break; 916 } 917 } 918 } else { 919 ipstat.ips_fragtimeout += 920 ipq[sum].prev->ipq_nfrags; 921 ip_freef(ipq[sum].prev); 922 } 923 } 924 found: 925 /* 926 * Adjust ip_len to not reflect header, 927 * convert offset of this to bytes. 928 */ 929 ip->ip_len -= hlen; 930 if (ip->ip_off & IP_MF) { 931 /* 932 * Make sure that fragments have a data length 933 * that's a non-zero multiple of 8 bytes. 934 */ 935 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 936 ipstat.ips_toosmall++; /* XXX */ 937 goto bad; 938 } 939 m->m_flags |= M_FRAG; 940 } else 941 m->m_flags &= ~M_FRAG; 942 ip->ip_off <<= 3; 943 944 /* 945 * Attempt reassembly; if it succeeds, proceed. 946 * ip_reass() will return a different mbuf, and update 947 * the divert info in divert_info. 948 */ 949 ipstat.ips_fragments++; 950 m->m_pkthdr.header = ip; 951 m = ip_reass(m, fp, &ipq[sum], &divert_info); 952 if (m == NULL) 953 return; 954 ipstat.ips_reassembled++; 955 needredispatch = TRUE; 956 ip = mtod(m, struct ip *); 957 /* Get the header length of the reassembled packet */ 958 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 959 #ifdef IPDIVERT 960 /* Restore original checksum before diverting packet */ 961 if (divert_info != 0) { 962 ip->ip_len += hlen; 963 ip->ip_len = htons(ip->ip_len); 964 ip->ip_off = htons(ip->ip_off); 965 ip->ip_sum = 0; 966 if (hlen == sizeof(struct ip)) 967 ip->ip_sum = in_cksum_hdr(ip); 968 else 969 ip->ip_sum = in_cksum(m, hlen); 970 ip->ip_off = ntohs(ip->ip_off); 971 ip->ip_len = ntohs(ip->ip_len); 972 ip->ip_len -= hlen; 973 } 974 #endif 975 } else { 976 ip->ip_len -= hlen; 977 } 978 979 #ifdef IPDIVERT 980 /* 981 * Divert or tee packet to the divert protocol if required. 982 */ 983 if (divert_info != 0) { 984 struct mbuf *clone = NULL; 985 986 /* Clone packet if we're doing a 'tee' */ 987 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 988 clone = m_dup(m, MB_DONTWAIT); 989 990 /* Restore packet header fields to original values */ 991 ip->ip_len += hlen; 992 ip->ip_len = htons(ip->ip_len); 993 ip->ip_off = htons(ip->ip_off); 994 995 /* Deliver packet to divert input routine */ 996 divert_packet(m, 1, divert_info & 0xffff); 997 ipstat.ips_delivered++; 998 999 /* If 'tee', continue with original packet */ 1000 if (clone == NULL) 1001 return; 1002 m = clone; 1003 ip = mtod(m, struct ip *); 1004 ip->ip_len += hlen; 1005 /* 1006 * Jump backwards to complete processing of the 1007 * packet. But first clear divert_info to avoid 1008 * entering this block again. 1009 * We do not need to clear args.divert_rule 1010 * or args.next_hop as they will not be used. 1011 * 1012 * XXX Better safe than sorry, remove the DIVERT tag. 1013 */ 1014 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 1015 if (mtag != NULL) 1016 m_tag_delete(m, mtag); 1017 1018 divert_info = 0; 1019 goto pass; 1020 } 1021 #endif 1022 1023 #ifdef IPSEC 1024 /* 1025 * enforce IPsec policy checking if we are seeing last header. 1026 * note that we do not visit this with protocols with pcb layer 1027 * code - like udp/tcp/raw ip. 1028 */ 1029 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 1030 ipsec4_in_reject(m, NULL)) { 1031 ipsecstat.in_polvio++; 1032 goto bad; 1033 } 1034 #endif 1035 #if FAST_IPSEC 1036 /* 1037 * enforce IPsec policy checking if we are seeing last header. 1038 * note that we do not visit this with protocols with pcb layer 1039 * code - like udp/tcp/raw ip. 1040 */ 1041 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 1042 /* 1043 * Check if the packet has already had IPsec processing 1044 * done. If so, then just pass it along. This tag gets 1045 * set during AH, ESP, etc. input handling, before the 1046 * packet is returned to the ip input queue for delivery. 1047 */ 1048 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 1049 crit_enter(); 1050 if (mtag != NULL) { 1051 tdbi = (struct tdb_ident *)m_tag_data(mtag); 1052 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 1053 } else { 1054 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 1055 IP_FORWARDING, &error); 1056 } 1057 if (sp != NULL) { 1058 /* 1059 * Check security policy against packet attributes. 1060 */ 1061 error = ipsec_in_reject(sp, m); 1062 KEY_FREESP(&sp); 1063 } else { 1064 /* XXX error stat??? */ 1065 error = EINVAL; 1066 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 1067 goto bad; 1068 } 1069 crit_exit(); 1070 if (error) 1071 goto bad; 1072 } 1073 #endif /* FAST_IPSEC */ 1074 1075 ipstat.ips_delivered++; 1076 if (needredispatch) { 1077 struct netmsg_transport_packet *msg; 1078 lwkt_port_t port; 1079 1080 ip->ip_off = htons(ip->ip_off); 1081 ip->ip_len = htons(ip->ip_len); 1082 port = ip_mport_in(&m); 1083 if (port == NULL) 1084 return; 1085 1086 msg = kmalloc(sizeof(struct netmsg_transport_packet), M_LWKTMSG, 1087 M_INTWAIT | M_NULLOK); 1088 if (msg == NULL) 1089 goto bad; 1090 1091 netmsg_init(&msg->nm_netmsg, &netisr_afree_rport, 0, 1092 transport_processing_handler); 1093 msg->nm_hlen = hlen; 1094 msg->nm_hasnexthop = (args.next_hop != NULL); 1095 if (msg->nm_hasnexthop) 1096 msg->nm_nexthop = *args.next_hop; /* structure copy */ 1097 1098 msg->nm_mbuf = m; 1099 ip = mtod(m, struct ip *); 1100 ip->ip_len = ntohs(ip->ip_len); 1101 ip->ip_off = ntohs(ip->ip_off); 1102 lwkt_sendmsg(port, &msg->nm_netmsg.nm_lmsg); 1103 } else { 1104 transport_processing_oncpu(m, hlen, ip, args.next_hop); 1105 } 1106 return; 1107 1108 bad: 1109 m_freem(m); 1110 } 1111 1112 /* 1113 * Take incoming datagram fragment and try to reassemble it into 1114 * whole datagram. If a chain for reassembly of this datagram already 1115 * exists, then it is given as fp; otherwise have to make a chain. 1116 * 1117 * When IPDIVERT enabled, keep additional state with each packet that 1118 * tells us if we need to divert or tee the packet we're building. 1119 * In particular, *divinfo includes the port and TEE flag. 1120 */ 1121 1122 static struct mbuf * 1123 ip_reass(struct mbuf *m, struct ipq *fp, struct ipq *where, 1124 u_int32_t *divinfo) 1125 { 1126 struct ip *ip = mtod(m, struct ip *); 1127 struct mbuf *p = NULL, *q, *nq; 1128 struct mbuf *n; 1129 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 1130 int i, next; 1131 #ifdef IPDIVERT 1132 struct m_tag *mtag; 1133 #endif 1134 1135 /* 1136 * If the hardware has not done csum over this fragment 1137 * then csum_data is not valid at all. 1138 */ 1139 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) 1140 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) { 1141 m->m_pkthdr.csum_data = 0; 1142 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR); 1143 } 1144 1145 /* 1146 * Presence of header sizes in mbufs 1147 * would confuse code below. 1148 */ 1149 m->m_data += hlen; 1150 m->m_len -= hlen; 1151 1152 /* 1153 * If first fragment to arrive, create a reassembly queue. 1154 */ 1155 if (fp == NULL) { 1156 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1157 goto dropfrag; 1158 insque(fp, where); 1159 nipq++; 1160 fp->ipq_nfrags = 1; 1161 fp->ipq_ttl = IPFRAGTTL; 1162 fp->ipq_p = ip->ip_p; 1163 fp->ipq_id = ip->ip_id; 1164 fp->ipq_src = ip->ip_src; 1165 fp->ipq_dst = ip->ip_dst; 1166 fp->ipq_frags = m; 1167 m->m_nextpkt = NULL; 1168 #ifdef IPDIVERT 1169 fp->ipq_div_info = 0; 1170 #endif 1171 goto inserted; 1172 } else { 1173 fp->ipq_nfrags++; 1174 } 1175 1176 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1177 1178 /* 1179 * Find a segment which begins after this one does. 1180 */ 1181 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1182 if (GETIP(q)->ip_off > ip->ip_off) 1183 break; 1184 1185 /* 1186 * If there is a preceding segment, it may provide some of 1187 * our data already. If so, drop the data from the incoming 1188 * segment. If it provides all of our data, drop us, otherwise 1189 * stick new segment in the proper place. 1190 * 1191 * If some of the data is dropped from the the preceding 1192 * segment, then it's checksum is invalidated. 1193 */ 1194 if (p) { 1195 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1196 if (i > 0) { 1197 if (i >= ip->ip_len) 1198 goto dropfrag; 1199 m_adj(m, i); 1200 m->m_pkthdr.csum_flags = 0; 1201 ip->ip_off += i; 1202 ip->ip_len -= i; 1203 } 1204 m->m_nextpkt = p->m_nextpkt; 1205 p->m_nextpkt = m; 1206 } else { 1207 m->m_nextpkt = fp->ipq_frags; 1208 fp->ipq_frags = m; 1209 } 1210 1211 /* 1212 * While we overlap succeeding segments trim them or, 1213 * if they are completely covered, dequeue them. 1214 */ 1215 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1216 q = nq) { 1217 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1218 if (i < GETIP(q)->ip_len) { 1219 GETIP(q)->ip_len -= i; 1220 GETIP(q)->ip_off += i; 1221 m_adj(q, i); 1222 q->m_pkthdr.csum_flags = 0; 1223 break; 1224 } 1225 nq = q->m_nextpkt; 1226 m->m_nextpkt = nq; 1227 ipstat.ips_fragdropped++; 1228 fp->ipq_nfrags--; 1229 q->m_nextpkt = NULL; 1230 m_freem(q); 1231 } 1232 1233 inserted: 1234 1235 #ifdef IPDIVERT 1236 /* 1237 * Transfer firewall instructions to the fragment structure. 1238 * Only trust info in the fragment at offset 0. 1239 */ 1240 if (ip->ip_off == 0) { 1241 fp->ipq_div_info = *divinfo; 1242 } else { 1243 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); 1244 if (mtag != NULL) 1245 m_tag_delete(m, mtag); 1246 } 1247 *divinfo = 0; 1248 #endif 1249 1250 /* 1251 * Check for complete reassembly and perform frag per packet 1252 * limiting. 1253 * 1254 * Frag limiting is performed here so that the nth frag has 1255 * a chance to complete the packet before we drop the packet. 1256 * As a result, n+1 frags are actually allowed per packet, but 1257 * only n will ever be stored. (n = maxfragsperpacket.) 1258 * 1259 */ 1260 next = 0; 1261 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1262 if (GETIP(q)->ip_off != next) { 1263 if (fp->ipq_nfrags > maxfragsperpacket) { 1264 ipstat.ips_fragdropped += fp->ipq_nfrags; 1265 ip_freef(fp); 1266 } 1267 return (NULL); 1268 } 1269 next += GETIP(q)->ip_len; 1270 } 1271 /* Make sure the last packet didn't have the IP_MF flag */ 1272 if (p->m_flags & M_FRAG) { 1273 if (fp->ipq_nfrags > maxfragsperpacket) { 1274 ipstat.ips_fragdropped += fp->ipq_nfrags; 1275 ip_freef(fp); 1276 } 1277 return (NULL); 1278 } 1279 1280 /* 1281 * Reassembly is complete. Make sure the packet is a sane size. 1282 */ 1283 q = fp->ipq_frags; 1284 ip = GETIP(q); 1285 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1286 ipstat.ips_toolong++; 1287 ipstat.ips_fragdropped += fp->ipq_nfrags; 1288 ip_freef(fp); 1289 return (NULL); 1290 } 1291 1292 /* 1293 * Concatenate fragments. 1294 */ 1295 m = q; 1296 n = m->m_next; 1297 m->m_next = NULL; 1298 m_cat(m, n); 1299 nq = q->m_nextpkt; 1300 q->m_nextpkt = NULL; 1301 for (q = nq; q != NULL; q = nq) { 1302 nq = q->m_nextpkt; 1303 q->m_nextpkt = NULL; 1304 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1305 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1306 m_cat(m, q); 1307 } 1308 1309 /* 1310 * Clean up the 1's complement checksum. Carry over 16 bits must 1311 * be added back. This assumes no more then 65535 packet fragments 1312 * were reassembled. A second carry can also occur (but not a third). 1313 */ 1314 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + 1315 (m->m_pkthdr.csum_data >> 16); 1316 if (m->m_pkthdr.csum_data > 0xFFFF) 1317 m->m_pkthdr.csum_data -= 0xFFFF; 1318 1319 1320 #ifdef IPDIVERT 1321 /* 1322 * Extract firewall instructions from the fragment structure. 1323 */ 1324 *divinfo = fp->ipq_div_info; 1325 #endif 1326 1327 /* 1328 * Create header for new ip packet by 1329 * modifying header of first packet; 1330 * dequeue and discard fragment reassembly header. 1331 * Make header visible. 1332 */ 1333 ip->ip_len = next; 1334 ip->ip_src = fp->ipq_src; 1335 ip->ip_dst = fp->ipq_dst; 1336 remque(fp); 1337 nipq--; 1338 mpipe_free(&ipq_mpipe, fp); 1339 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1340 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1341 /* some debugging cruft by sklower, below, will go away soon */ 1342 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1343 int plen = 0; 1344 1345 for (n = m; n; n = n->m_next) 1346 plen += n->m_len; 1347 m->m_pkthdr.len = plen; 1348 } 1349 return (m); 1350 1351 dropfrag: 1352 #ifdef IPDIVERT 1353 *divinfo = 0; 1354 #endif 1355 ipstat.ips_fragdropped++; 1356 if (fp != NULL) 1357 fp->ipq_nfrags--; 1358 m_freem(m); 1359 return (NULL); 1360 1361 #undef GETIP 1362 } 1363 1364 /* 1365 * Free a fragment reassembly header and all 1366 * associated datagrams. 1367 */ 1368 static void 1369 ip_freef(struct ipq *fp) 1370 { 1371 struct mbuf *q; 1372 1373 while (fp->ipq_frags) { 1374 q = fp->ipq_frags; 1375 fp->ipq_frags = q->m_nextpkt; 1376 q->m_nextpkt = NULL; 1377 m_freem(q); 1378 } 1379 remque(fp); 1380 mpipe_free(&ipq_mpipe, fp); 1381 nipq--; 1382 } 1383 1384 /* 1385 * IP timer processing; 1386 * if a timer expires on a reassembly 1387 * queue, discard it. 1388 */ 1389 void 1390 ip_slowtimo(void) 1391 { 1392 struct ipq *fp; 1393 int i; 1394 1395 crit_enter(); 1396 for (i = 0; i < IPREASS_NHASH; i++) { 1397 fp = ipq[i].next; 1398 if (fp == NULL) 1399 continue; 1400 while (fp != &ipq[i]) { 1401 --fp->ipq_ttl; 1402 fp = fp->next; 1403 if (fp->prev->ipq_ttl == 0) { 1404 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1405 ip_freef(fp->prev); 1406 } 1407 } 1408 } 1409 /* 1410 * If we are over the maximum number of fragments 1411 * (due to the limit being lowered), drain off 1412 * enough to get down to the new limit. 1413 */ 1414 if (maxnipq >= 0 && nipq > maxnipq) { 1415 for (i = 0; i < IPREASS_NHASH; i++) { 1416 while (nipq > maxnipq && 1417 (ipq[i].next != &ipq[i])) { 1418 ipstat.ips_fragdropped += 1419 ipq[i].next->ipq_nfrags; 1420 ip_freef(ipq[i].next); 1421 } 1422 } 1423 } 1424 ipflow_slowtimo(); 1425 crit_exit(); 1426 } 1427 1428 /* 1429 * Drain off all datagram fragments. 1430 */ 1431 void 1432 ip_drain(void) 1433 { 1434 int i; 1435 1436 for (i = 0; i < IPREASS_NHASH; i++) { 1437 while (ipq[i].next != &ipq[i]) { 1438 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1439 ip_freef(ipq[i].next); 1440 } 1441 } 1442 in_rtqdrain(); 1443 } 1444 1445 /* 1446 * Do option processing on a datagram, 1447 * possibly discarding it if bad options are encountered, 1448 * or forwarding it if source-routed. 1449 * The pass argument is used when operating in the IPSTEALTH 1450 * mode to tell what options to process: 1451 * [LS]SRR (pass 0) or the others (pass 1). 1452 * The reason for as many as two passes is that when doing IPSTEALTH, 1453 * non-routing options should be processed only if the packet is for us. 1454 * Returns 1 if packet has been forwarded/freed, 1455 * 0 if the packet should be processed further. 1456 */ 1457 static int 1458 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1459 { 1460 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1461 struct ip *ip = mtod(m, struct ip *); 1462 u_char *cp; 1463 struct in_ifaddr *ia; 1464 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1465 boolean_t forward = FALSE; 1466 struct in_addr *sin, dst; 1467 n_time ntime; 1468 1469 dst = ip->ip_dst; 1470 cp = (u_char *)(ip + 1); 1471 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1472 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1473 opt = cp[IPOPT_OPTVAL]; 1474 if (opt == IPOPT_EOL) 1475 break; 1476 if (opt == IPOPT_NOP) 1477 optlen = 1; 1478 else { 1479 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1480 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1481 goto bad; 1482 } 1483 optlen = cp[IPOPT_OLEN]; 1484 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1485 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1486 goto bad; 1487 } 1488 } 1489 switch (opt) { 1490 1491 default: 1492 break; 1493 1494 /* 1495 * Source routing with record. 1496 * Find interface with current destination address. 1497 * If none on this machine then drop if strictly routed, 1498 * or do nothing if loosely routed. 1499 * Record interface address and bring up next address 1500 * component. If strictly routed make sure next 1501 * address is on directly accessible net. 1502 */ 1503 case IPOPT_LSRR: 1504 case IPOPT_SSRR: 1505 if (ipstealth && pass > 0) 1506 break; 1507 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1508 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1509 goto bad; 1510 } 1511 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1512 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1513 goto bad; 1514 } 1515 ipaddr.sin_addr = ip->ip_dst; 1516 ia = (struct in_ifaddr *) 1517 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1518 if (ia == NULL) { 1519 if (opt == IPOPT_SSRR) { 1520 type = ICMP_UNREACH; 1521 code = ICMP_UNREACH_SRCFAIL; 1522 goto bad; 1523 } 1524 if (!ip_dosourceroute) 1525 goto nosourcerouting; 1526 /* 1527 * Loose routing, and not at next destination 1528 * yet; nothing to do except forward. 1529 */ 1530 break; 1531 } 1532 off--; /* 0 origin */ 1533 if (off > optlen - (int)sizeof(struct in_addr)) { 1534 /* 1535 * End of source route. Should be for us. 1536 */ 1537 if (!ip_acceptsourceroute) 1538 goto nosourcerouting; 1539 save_rte(cp, ip->ip_src); 1540 break; 1541 } 1542 if (ipstealth) 1543 goto dropit; 1544 if (!ip_dosourceroute) { 1545 if (ipforwarding) { 1546 char buf[sizeof "aaa.bbb.ccc.ddd"]; 1547 1548 /* 1549 * Acting as a router, so generate ICMP 1550 */ 1551 nosourcerouting: 1552 strcpy(buf, inet_ntoa(ip->ip_dst)); 1553 log(LOG_WARNING, 1554 "attempted source route from %s to %s\n", 1555 inet_ntoa(ip->ip_src), buf); 1556 type = ICMP_UNREACH; 1557 code = ICMP_UNREACH_SRCFAIL; 1558 goto bad; 1559 } else { 1560 /* 1561 * Not acting as a router, 1562 * so silently drop. 1563 */ 1564 dropit: 1565 ipstat.ips_cantforward++; 1566 m_freem(m); 1567 return (1); 1568 } 1569 } 1570 1571 /* 1572 * locate outgoing interface 1573 */ 1574 memcpy(&ipaddr.sin_addr, cp + off, 1575 sizeof ipaddr.sin_addr); 1576 1577 if (opt == IPOPT_SSRR) { 1578 #define INA struct in_ifaddr * 1579 #define SA struct sockaddr * 1580 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1581 == NULL) 1582 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1583 } else 1584 ia = ip_rtaddr(ipaddr.sin_addr, 1585 &ipforward_rt[mycpuid]); 1586 if (ia == NULL) { 1587 type = ICMP_UNREACH; 1588 code = ICMP_UNREACH_SRCFAIL; 1589 goto bad; 1590 } 1591 ip->ip_dst = ipaddr.sin_addr; 1592 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1593 sizeof(struct in_addr)); 1594 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1595 /* 1596 * Let ip_intr's mcast routing check handle mcast pkts 1597 */ 1598 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1599 break; 1600 1601 case IPOPT_RR: 1602 if (ipstealth && pass == 0) 1603 break; 1604 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1605 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1606 goto bad; 1607 } 1608 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1609 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1610 goto bad; 1611 } 1612 /* 1613 * If no space remains, ignore. 1614 */ 1615 off--; /* 0 origin */ 1616 if (off > optlen - (int)sizeof(struct in_addr)) 1617 break; 1618 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1619 sizeof ipaddr.sin_addr); 1620 /* 1621 * locate outgoing interface; if we're the destination, 1622 * use the incoming interface (should be same). 1623 */ 1624 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1625 (ia = ip_rtaddr(ipaddr.sin_addr, 1626 &ipforward_rt[mycpuid])) 1627 == NULL) { 1628 type = ICMP_UNREACH; 1629 code = ICMP_UNREACH_HOST; 1630 goto bad; 1631 } 1632 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1633 sizeof(struct in_addr)); 1634 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1635 break; 1636 1637 case IPOPT_TS: 1638 if (ipstealth && pass == 0) 1639 break; 1640 code = cp - (u_char *)ip; 1641 if (optlen < 4 || optlen > 40) { 1642 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1643 goto bad; 1644 } 1645 if ((off = cp[IPOPT_OFFSET]) < 5) { 1646 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1647 goto bad; 1648 } 1649 if (off > optlen - (int)sizeof(int32_t)) { 1650 cp[IPOPT_OFFSET + 1] += (1 << 4); 1651 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1652 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1653 goto bad; 1654 } 1655 break; 1656 } 1657 off--; /* 0 origin */ 1658 sin = (struct in_addr *)(cp + off); 1659 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1660 1661 case IPOPT_TS_TSONLY: 1662 break; 1663 1664 case IPOPT_TS_TSANDADDR: 1665 if (off + sizeof(n_time) + 1666 sizeof(struct in_addr) > optlen) { 1667 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1668 goto bad; 1669 } 1670 ipaddr.sin_addr = dst; 1671 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1672 m->m_pkthdr.rcvif); 1673 if (ia == NULL) 1674 continue; 1675 memcpy(sin, &IA_SIN(ia)->sin_addr, 1676 sizeof(struct in_addr)); 1677 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1678 off += sizeof(struct in_addr); 1679 break; 1680 1681 case IPOPT_TS_PRESPEC: 1682 if (off + sizeof(n_time) + 1683 sizeof(struct in_addr) > optlen) { 1684 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1685 goto bad; 1686 } 1687 memcpy(&ipaddr.sin_addr, sin, 1688 sizeof(struct in_addr)); 1689 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1690 continue; 1691 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1692 off += sizeof(struct in_addr); 1693 break; 1694 1695 default: 1696 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1697 goto bad; 1698 } 1699 ntime = iptime(); 1700 memcpy(cp + off, &ntime, sizeof(n_time)); 1701 cp[IPOPT_OFFSET] += sizeof(n_time); 1702 } 1703 } 1704 if (forward && ipforwarding) { 1705 ip_forward(m, TRUE, next_hop); 1706 return (1); 1707 } 1708 return (0); 1709 bad: 1710 icmp_error(m, type, code, 0, 0); 1711 ipstat.ips_badoptions++; 1712 return (1); 1713 } 1714 1715 /* 1716 * Given address of next destination (final or next hop), 1717 * return internet address info of interface to be used to get there. 1718 */ 1719 struct in_ifaddr * 1720 ip_rtaddr(struct in_addr dst, struct route *ro) 1721 { 1722 struct sockaddr_in *sin; 1723 1724 sin = (struct sockaddr_in *)&ro->ro_dst; 1725 1726 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1727 if (ro->ro_rt != NULL) { 1728 RTFREE(ro->ro_rt); 1729 ro->ro_rt = NULL; 1730 } 1731 sin->sin_family = AF_INET; 1732 sin->sin_len = sizeof *sin; 1733 sin->sin_addr = dst; 1734 rtalloc_ign(ro, RTF_PRCLONING); 1735 } 1736 1737 if (ro->ro_rt == NULL) 1738 return (NULL); 1739 1740 return (ifatoia(ro->ro_rt->rt_ifa)); 1741 } 1742 1743 /* 1744 * Save incoming source route for use in replies, 1745 * to be picked up later by ip_srcroute if the receiver is interested. 1746 */ 1747 void 1748 save_rte(u_char *option, struct in_addr dst) 1749 { 1750 unsigned olen; 1751 1752 olen = option[IPOPT_OLEN]; 1753 #ifdef DIAGNOSTIC 1754 if (ipprintfs) 1755 kprintf("save_rte: olen %d\n", olen); 1756 #endif 1757 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1758 return; 1759 bcopy(option, ip_srcrt.srcopt, olen); 1760 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1761 ip_srcrt.dst = dst; 1762 } 1763 1764 /* 1765 * Retrieve incoming source route for use in replies, 1766 * in the same form used by setsockopt. 1767 * The first hop is placed before the options, will be removed later. 1768 */ 1769 struct mbuf * 1770 ip_srcroute(void) 1771 { 1772 struct in_addr *p, *q; 1773 struct mbuf *m; 1774 1775 if (ip_nhops == 0) 1776 return (NULL); 1777 m = m_get(MB_DONTWAIT, MT_HEADER); 1778 if (m == NULL) 1779 return (NULL); 1780 1781 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1782 1783 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1784 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1785 OPTSIZ; 1786 #ifdef DIAGNOSTIC 1787 if (ipprintfs) 1788 kprintf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1789 #endif 1790 1791 /* 1792 * First save first hop for return route 1793 */ 1794 p = &ip_srcrt.route[ip_nhops - 1]; 1795 *(mtod(m, struct in_addr *)) = *p--; 1796 #ifdef DIAGNOSTIC 1797 if (ipprintfs) 1798 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1799 #endif 1800 1801 /* 1802 * Copy option fields and padding (nop) to mbuf. 1803 */ 1804 ip_srcrt.nop = IPOPT_NOP; 1805 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1806 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &ip_srcrt.nop, 1807 OPTSIZ); 1808 q = (struct in_addr *)(mtod(m, caddr_t) + 1809 sizeof(struct in_addr) + OPTSIZ); 1810 #undef OPTSIZ 1811 /* 1812 * Record return path as an IP source route, 1813 * reversing the path (pointers are now aligned). 1814 */ 1815 while (p >= ip_srcrt.route) { 1816 #ifdef DIAGNOSTIC 1817 if (ipprintfs) 1818 kprintf(" %x", ntohl(q->s_addr)); 1819 #endif 1820 *q++ = *p--; 1821 } 1822 /* 1823 * Last hop goes to final destination. 1824 */ 1825 *q = ip_srcrt.dst; 1826 #ifdef DIAGNOSTIC 1827 if (ipprintfs) 1828 kprintf(" %x\n", ntohl(q->s_addr)); 1829 #endif 1830 return (m); 1831 } 1832 1833 /* 1834 * Strip out IP options. 1835 */ 1836 void 1837 ip_stripoptions(struct mbuf *m) 1838 { 1839 int datalen; 1840 struct ip *ip = mtod(m, struct ip *); 1841 caddr_t opts; 1842 int optlen; 1843 1844 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1845 opts = (caddr_t)(ip + 1); 1846 datalen = m->m_len - (sizeof(struct ip) + optlen); 1847 bcopy(opts + optlen, opts, datalen); 1848 m->m_len -= optlen; 1849 if (m->m_flags & M_PKTHDR) 1850 m->m_pkthdr.len -= optlen; 1851 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1852 } 1853 1854 u_char inetctlerrmap[PRC_NCMDS] = { 1855 0, 0, 0, 0, 1856 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1857 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1858 EMSGSIZE, EHOSTUNREACH, 0, 0, 1859 0, 0, 0, 0, 1860 ENOPROTOOPT, ECONNREFUSED 1861 }; 1862 1863 /* 1864 * Forward a packet. If some error occurs return the sender 1865 * an icmp packet. Note we can't always generate a meaningful 1866 * icmp message because icmp doesn't have a large enough repertoire 1867 * of codes and types. 1868 * 1869 * If not forwarding, just drop the packet. This could be confusing 1870 * if ipforwarding was zero but some routing protocol was advancing 1871 * us as a gateway to somewhere. However, we must let the routing 1872 * protocol deal with that. 1873 * 1874 * The using_srcrt parameter indicates whether the packet is being forwarded 1875 * via a source route. 1876 */ 1877 void 1878 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop) 1879 { 1880 struct ip *ip = mtod(m, struct ip *); 1881 struct sockaddr_in *ipforward_rtaddr; 1882 struct rtentry *rt; 1883 int error, type = 0, code = 0, destmtu = 0; 1884 struct mbuf *mcopy; 1885 n_long dest; 1886 struct in_addr pkt_dst; 1887 struct m_hdr tag; 1888 struct route *cache_rt = &ipforward_rt[mycpuid]; 1889 1890 dest = INADDR_ANY; 1891 /* 1892 * Cache the destination address of the packet; this may be 1893 * changed by use of 'ipfw fwd'. 1894 */ 1895 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 1896 1897 #ifdef DIAGNOSTIC 1898 if (ipprintfs) 1899 kprintf("forward: src %x dst %x ttl %x\n", 1900 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1901 #endif 1902 1903 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1904 ipstat.ips_cantforward++; 1905 m_freem(m); 1906 return; 1907 } 1908 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1909 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1910 return; 1911 } 1912 1913 ipforward_rtaddr = (struct sockaddr_in *) &cache_rt->ro_dst; 1914 if (cache_rt->ro_rt == NULL || 1915 ipforward_rtaddr->sin_addr.s_addr != pkt_dst.s_addr) { 1916 if (cache_rt->ro_rt != NULL) { 1917 RTFREE(cache_rt->ro_rt); 1918 cache_rt->ro_rt = NULL; 1919 } 1920 ipforward_rtaddr->sin_family = AF_INET; 1921 ipforward_rtaddr->sin_len = sizeof(struct sockaddr_in); 1922 ipforward_rtaddr->sin_addr = pkt_dst; 1923 rtalloc_ign(cache_rt, RTF_PRCLONING); 1924 if (cache_rt->ro_rt == NULL) { 1925 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1926 return; 1927 } 1928 } 1929 rt = cache_rt->ro_rt; 1930 1931 /* 1932 * Save the IP header and at most 8 bytes of the payload, 1933 * in case we need to generate an ICMP message to the src. 1934 * 1935 * XXX this can be optimized a lot by saving the data in a local 1936 * buffer on the stack (72 bytes at most), and only allocating the 1937 * mbuf if really necessary. The vast majority of the packets 1938 * are forwarded without having to send an ICMP back (either 1939 * because unnecessary, or because rate limited), so we are 1940 * really we are wasting a lot of work here. 1941 * 1942 * We don't use m_copy() because it might return a reference 1943 * to a shared cluster. Both this function and ip_output() 1944 * assume exclusive access to the IP header in `m', so any 1945 * data in a cluster may change before we reach icmp_error(). 1946 */ 1947 MGETHDR(mcopy, MB_DONTWAIT, m->m_type); 1948 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) { 1949 /* 1950 * It's probably ok if the pkthdr dup fails (because 1951 * the deep copy of the tag chain failed), but for now 1952 * be conservative and just discard the copy since 1953 * code below may some day want the tags. 1954 */ 1955 m_free(mcopy); 1956 mcopy = NULL; 1957 } 1958 if (mcopy != NULL) { 1959 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1960 (int)ip->ip_len); 1961 mcopy->m_pkthdr.len = mcopy->m_len; 1962 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1963 } 1964 1965 if (!ipstealth) 1966 ip->ip_ttl -= IPTTLDEC; 1967 1968 /* 1969 * If forwarding packet using same interface that it came in on, 1970 * perhaps should send a redirect to sender to shortcut a hop. 1971 * Only send redirect if source is sending directly to us, 1972 * and if packet was not source routed (or has any options). 1973 * Also, don't send redirect if forwarding using a default route 1974 * or a route modified by a redirect. 1975 */ 1976 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1977 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1978 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1979 ipsendredirects && !using_srcrt && next_hop == NULL) { 1980 u_long src = ntohl(ip->ip_src.s_addr); 1981 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa; 1982 1983 if (rt_ifa != NULL && 1984 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) { 1985 if (rt->rt_flags & RTF_GATEWAY) 1986 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1987 else 1988 dest = pkt_dst.s_addr; 1989 /* 1990 * Router requirements says to only send 1991 * host redirects. 1992 */ 1993 type = ICMP_REDIRECT; 1994 code = ICMP_REDIRECT_HOST; 1995 #ifdef DIAGNOSTIC 1996 if (ipprintfs) 1997 kprintf("redirect (%d) to %x\n", code, dest); 1998 #endif 1999 } 2000 } 2001 2002 if (next_hop != NULL) { 2003 /* Pass IPFORWARD info if available */ 2004 tag.mh_type = MT_TAG; 2005 tag.mh_flags = PACKET_TAG_IPFORWARD; 2006 tag.mh_data = (caddr_t)next_hop; 2007 tag.mh_next = m; 2008 m = (struct mbuf *)&tag; 2009 } 2010 2011 error = ip_output(m, NULL, cache_rt, IP_FORWARDING, NULL, 2012 NULL); 2013 if (error == 0) { 2014 ipstat.ips_forward++; 2015 if (type == 0) { 2016 if (mcopy) { 2017 /* ipflow_create() will free mcopy */ 2018 ipflow_create(cache_rt, mcopy); 2019 } 2020 return; /* most common case */ 2021 } else { 2022 ipstat.ips_redirectsent++; 2023 } 2024 } else { 2025 ipstat.ips_cantforward++; 2026 } 2027 2028 if (mcopy == NULL) 2029 return; 2030 2031 /* 2032 * Send ICMP message. 2033 */ 2034 2035 switch (error) { 2036 2037 case 0: /* forwarded, but need redirect */ 2038 /* type, code set above */ 2039 break; 2040 2041 case ENETUNREACH: /* shouldn't happen, checked above */ 2042 case EHOSTUNREACH: 2043 case ENETDOWN: 2044 case EHOSTDOWN: 2045 default: 2046 type = ICMP_UNREACH; 2047 code = ICMP_UNREACH_HOST; 2048 break; 2049 2050 case EMSGSIZE: 2051 type = ICMP_UNREACH; 2052 code = ICMP_UNREACH_NEEDFRAG; 2053 #ifdef IPSEC 2054 /* 2055 * If the packet is routed over IPsec tunnel, tell the 2056 * originator the tunnel MTU. 2057 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2058 * XXX quickhack!!! 2059 */ 2060 if (cache_rt->ro_rt != NULL) { 2061 struct secpolicy *sp = NULL; 2062 int ipsecerror; 2063 int ipsechdr; 2064 struct route *ro; 2065 2066 sp = ipsec4_getpolicybyaddr(mcopy, 2067 IPSEC_DIR_OUTBOUND, 2068 IP_FORWARDING, 2069 &ipsecerror); 2070 2071 if (sp == NULL) 2072 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2073 else { 2074 /* count IPsec header size */ 2075 ipsechdr = ipsec4_hdrsiz(mcopy, 2076 IPSEC_DIR_OUTBOUND, 2077 NULL); 2078 2079 /* 2080 * find the correct route for outer IPv4 2081 * header, compute tunnel MTU. 2082 * 2083 */ 2084 if (sp->req != NULL && sp->req->sav != NULL && 2085 sp->req->sav->sah != NULL) { 2086 ro = &sp->req->sav->sah->sa_route; 2087 if (ro->ro_rt != NULL && 2088 ro->ro_rt->rt_ifp != NULL) { 2089 destmtu = 2090 ro->ro_rt->rt_ifp->if_mtu; 2091 destmtu -= ipsechdr; 2092 } 2093 } 2094 2095 key_freesp(sp); 2096 } 2097 } 2098 #elif FAST_IPSEC 2099 /* 2100 * If the packet is routed over IPsec tunnel, tell the 2101 * originator the tunnel MTU. 2102 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2103 * XXX quickhack!!! 2104 */ 2105 if (cache_rt->ro_rt != NULL) { 2106 struct secpolicy *sp = NULL; 2107 int ipsecerror; 2108 int ipsechdr; 2109 struct route *ro; 2110 2111 sp = ipsec_getpolicybyaddr(mcopy, 2112 IPSEC_DIR_OUTBOUND, 2113 IP_FORWARDING, 2114 &ipsecerror); 2115 2116 if (sp == NULL) 2117 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2118 else { 2119 /* count IPsec header size */ 2120 ipsechdr = ipsec4_hdrsiz(mcopy, 2121 IPSEC_DIR_OUTBOUND, 2122 NULL); 2123 2124 /* 2125 * find the correct route for outer IPv4 2126 * header, compute tunnel MTU. 2127 */ 2128 2129 if (sp->req != NULL && 2130 sp->req->sav != NULL && 2131 sp->req->sav->sah != NULL) { 2132 ro = &sp->req->sav->sah->sa_route; 2133 if (ro->ro_rt != NULL && 2134 ro->ro_rt->rt_ifp != NULL) { 2135 destmtu = 2136 ro->ro_rt->rt_ifp->if_mtu; 2137 destmtu -= ipsechdr; 2138 } 2139 } 2140 2141 KEY_FREESP(&sp); 2142 } 2143 } 2144 #else /* !IPSEC && !FAST_IPSEC */ 2145 if (cache_rt->ro_rt != NULL) 2146 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2147 #endif /*IPSEC*/ 2148 ipstat.ips_cantfrag++; 2149 break; 2150 2151 case ENOBUFS: 2152 /* 2153 * A router should not generate ICMP_SOURCEQUENCH as 2154 * required in RFC1812 Requirements for IP Version 4 Routers. 2155 * Source quench could be a big problem under DoS attacks, 2156 * or if the underlying interface is rate-limited. 2157 * Those who need source quench packets may re-enable them 2158 * via the net.inet.ip.sendsourcequench sysctl. 2159 */ 2160 if (!ip_sendsourcequench) { 2161 m_freem(mcopy); 2162 return; 2163 } else { 2164 type = ICMP_SOURCEQUENCH; 2165 code = 0; 2166 } 2167 break; 2168 2169 case EACCES: /* ipfw denied packet */ 2170 m_freem(mcopy); 2171 return; 2172 } 2173 icmp_error(mcopy, type, code, dest, destmtu); 2174 } 2175 2176 void 2177 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2178 struct mbuf *m) 2179 { 2180 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2181 struct timeval tv; 2182 2183 microtime(&tv); 2184 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2185 SCM_TIMESTAMP, SOL_SOCKET); 2186 if (*mp) 2187 mp = &(*mp)->m_next; 2188 } 2189 if (inp->inp_flags & INP_RECVDSTADDR) { 2190 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2191 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2192 if (*mp) 2193 mp = &(*mp)->m_next; 2194 } 2195 if (inp->inp_flags & INP_RECVTTL) { 2196 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2197 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2198 if (*mp) 2199 mp = &(*mp)->m_next; 2200 } 2201 #ifdef notyet 2202 /* XXX 2203 * Moving these out of udp_input() made them even more broken 2204 * than they already were. 2205 */ 2206 /* options were tossed already */ 2207 if (inp->inp_flags & INP_RECVOPTS) { 2208 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2209 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2210 if (*mp) 2211 mp = &(*mp)->m_next; 2212 } 2213 /* ip_srcroute doesn't do what we want here, need to fix */ 2214 if (inp->inp_flags & INP_RECVRETOPTS) { 2215 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2216 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2217 if (*mp) 2218 mp = &(*mp)->m_next; 2219 } 2220 #endif 2221 if (inp->inp_flags & INP_RECVIF) { 2222 struct ifnet *ifp; 2223 struct sdlbuf { 2224 struct sockaddr_dl sdl; 2225 u_char pad[32]; 2226 } sdlbuf; 2227 struct sockaddr_dl *sdp; 2228 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2229 2230 if (((ifp = m->m_pkthdr.rcvif)) && 2231 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2232 sdp = IF_LLSOCKADDR(ifp); 2233 /* 2234 * Change our mind and don't try copy. 2235 */ 2236 if ((sdp->sdl_family != AF_LINK) || 2237 (sdp->sdl_len > sizeof(sdlbuf))) { 2238 goto makedummy; 2239 } 2240 bcopy(sdp, sdl2, sdp->sdl_len); 2241 } else { 2242 makedummy: 2243 sdl2->sdl_len = 2244 offsetof(struct sockaddr_dl, sdl_data[0]); 2245 sdl2->sdl_family = AF_LINK; 2246 sdl2->sdl_index = 0; 2247 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2248 } 2249 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2250 IP_RECVIF, IPPROTO_IP); 2251 if (*mp) 2252 mp = &(*mp)->m_next; 2253 } 2254 } 2255 2256 /* 2257 * XXX these routines are called from the upper part of the kernel. 2258 * 2259 * They could also be moved to ip_mroute.c, since all the RSVP 2260 * handling is done there already. 2261 */ 2262 int 2263 ip_rsvp_init(struct socket *so) 2264 { 2265 if (so->so_type != SOCK_RAW || 2266 so->so_proto->pr_protocol != IPPROTO_RSVP) 2267 return EOPNOTSUPP; 2268 2269 if (ip_rsvpd != NULL) 2270 return EADDRINUSE; 2271 2272 ip_rsvpd = so; 2273 /* 2274 * This may seem silly, but we need to be sure we don't over-increment 2275 * the RSVP counter, in case something slips up. 2276 */ 2277 if (!ip_rsvp_on) { 2278 ip_rsvp_on = 1; 2279 rsvp_on++; 2280 } 2281 2282 return 0; 2283 } 2284 2285 int 2286 ip_rsvp_done(void) 2287 { 2288 ip_rsvpd = NULL; 2289 /* 2290 * This may seem silly, but we need to be sure we don't over-decrement 2291 * the RSVP counter, in case something slips up. 2292 */ 2293 if (ip_rsvp_on) { 2294 ip_rsvp_on = 0; 2295 rsvp_on--; 2296 } 2297 return 0; 2298 } 2299 2300 void 2301 rsvp_input(struct mbuf *m, ...) /* XXX must fixup manually */ 2302 { 2303 int off, proto; 2304 __va_list ap; 2305 2306 __va_start(ap, m); 2307 off = __va_arg(ap, int); 2308 proto = __va_arg(ap, int); 2309 __va_end(ap); 2310 2311 if (rsvp_input_p) { /* call the real one if loaded */ 2312 rsvp_input_p(m, off, proto); 2313 return; 2314 } 2315 2316 /* Can still get packets with rsvp_on = 0 if there is a local member 2317 * of the group to which the RSVP packet is addressed. But in this 2318 * case we want to throw the packet away. 2319 */ 2320 2321 if (!rsvp_on) { 2322 m_freem(m); 2323 return; 2324 } 2325 2326 if (ip_rsvpd != NULL) { 2327 rip_input(m, off, proto); 2328 return; 2329 } 2330 /* Drop the packet */ 2331 m_freem(m); 2332 } 2333