1 /* 2 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved. 3 * Copyright (c) 2003, 2004 The DragonFly Project. All rights reserved. 4 * 5 * This code is derived from software contributed to The DragonFly Project 6 * by Jeffrey M. Hsu. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of The DragonFly Project nor the names of its 17 * contributors may be used to endorse or promote products derived 18 * from this software without specific, prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright (c) 1982, 1986, 1988, 1993 36 * The Regents of the University of California. All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. All advertising materials mentioning features or use of this software 47 * must display the following acknowledgement: 48 * This product includes software developed by the University of 49 * California, Berkeley and its contributors. 50 * 4. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 67 * $FreeBSD: src/sys/netinet/ip_input.c,v 1.130.2.52 2003/03/07 07:01:28 silby Exp $ 68 * $DragonFly: src/sys/netinet/ip_input.c,v 1.115 2008/10/28 07:09:26 sephe Exp $ 69 */ 70 71 #define _IP_VHL 72 73 #include "opt_bootp.h" 74 #include "opt_ipfw.h" 75 #include "opt_ipdn.h" 76 #include "opt_ipdivert.h" 77 #include "opt_ipfilter.h" 78 #include "opt_ipstealth.h" 79 #include "opt_ipsec.h" 80 81 #include <sys/param.h> 82 #include <sys/systm.h> 83 #include <sys/mbuf.h> 84 #include <sys/malloc.h> 85 #include <sys/mpipe.h> 86 #include <sys/domain.h> 87 #include <sys/protosw.h> 88 #include <sys/socket.h> 89 #include <sys/time.h> 90 #include <sys/globaldata.h> 91 #include <sys/thread.h> 92 #include <sys/kernel.h> 93 #include <sys/syslog.h> 94 #include <sys/sysctl.h> 95 #include <sys/in_cksum.h> 96 #include <sys/lock.h> 97 98 #include <sys/mplock2.h> 99 100 #include <machine/stdarg.h> 101 102 #include <net/if.h> 103 #include <net/if_types.h> 104 #include <net/if_var.h> 105 #include <net/if_dl.h> 106 #include <net/pfil.h> 107 #include <net/route.h> 108 #include <net/netisr.h> 109 110 #include <netinet/in.h> 111 #include <netinet/in_systm.h> 112 #include <netinet/in_var.h> 113 #include <netinet/ip.h> 114 #include <netinet/in_pcb.h> 115 #include <netinet/ip_var.h> 116 #include <netinet/ip_icmp.h> 117 #include <netinet/ip_divert.h> 118 #include <netinet/ip_flow.h> 119 120 #include <sys/thread2.h> 121 #include <sys/msgport2.h> 122 #include <net/netmsg2.h> 123 124 #include <sys/socketvar.h> 125 126 #include <net/ipfw/ip_fw.h> 127 #include <net/dummynet/ip_dummynet.h> 128 129 #ifdef IPSEC 130 #include <netinet6/ipsec.h> 131 #include <netproto/key/key.h> 132 #endif 133 134 #ifdef FAST_IPSEC 135 #include <netproto/ipsec/ipsec.h> 136 #include <netproto/ipsec/key.h> 137 #endif 138 139 int rsvp_on = 0; 140 static int ip_rsvp_on; 141 struct socket *ip_rsvpd; 142 143 int ipforwarding = 0; 144 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 145 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 146 147 static int ipsendredirects = 1; /* XXX */ 148 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 149 &ipsendredirects, 0, "Enable sending IP redirects"); 150 151 int ip_defttl = IPDEFTTL; 152 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 153 &ip_defttl, 0, "Maximum TTL on IP packets"); 154 155 static int ip_dosourceroute = 0; 156 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 157 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 158 159 static int ip_acceptsourceroute = 0; 160 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 161 CTLFLAG_RW, &ip_acceptsourceroute, 0, 162 "Enable accepting source routed IP packets"); 163 164 static int ip_keepfaith = 0; 165 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 166 &ip_keepfaith, 0, 167 "Enable packet capture for FAITH IPv4->IPv6 translator daemon"); 168 169 static int nipq = 0; /* total # of reass queues */ 170 static int maxnipq; 171 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 172 &maxnipq, 0, 173 "Maximum number of IPv4 fragment reassembly queue entries"); 174 175 static int maxfragsperpacket; 176 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 177 &maxfragsperpacket, 0, 178 "Maximum number of IPv4 fragments allowed per packet"); 179 180 static int ip_sendsourcequench = 0; 181 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 182 &ip_sendsourcequench, 0, 183 "Enable the transmission of source quench packets"); 184 185 int ip_do_randomid = 1; 186 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 187 &ip_do_randomid, 0, 188 "Assign random ip_id values"); 189 /* 190 * XXX - Setting ip_checkinterface mostly implements the receive side of 191 * the Strong ES model described in RFC 1122, but since the routing table 192 * and transmit implementation do not implement the Strong ES model, 193 * setting this to 1 results in an odd hybrid. 194 * 195 * XXX - ip_checkinterface currently must be disabled if you use ipnat 196 * to translate the destination address to another local interface. 197 * 198 * XXX - ip_checkinterface must be disabled if you add IP aliases 199 * to the loopback interface instead of the interface where the 200 * packets for those addresses are received. 201 */ 202 static int ip_checkinterface = 0; 203 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 204 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 205 206 static int ip_dispatch_fast = 0; 207 static int ip_dispatch_slow = 0; 208 static int ip_dispatch_recheck = 0; 209 static int ip_dispatch_software = 0; 210 SYSCTL_INT(_net_inet_ip, OID_AUTO, dispatch_fast_count, CTLFLAG_RW, 211 &ip_dispatch_fast, 0, ""); 212 SYSCTL_INT(_net_inet_ip, OID_AUTO, dispatch_slow_count, CTLFLAG_RW, 213 &ip_dispatch_slow, 0, ""); 214 SYSCTL_INT(_net_inet_ip, OID_AUTO, dispatch_software_count, CTLFLAG_RW, 215 &ip_dispatch_software, 0, ""); 216 SYSCTL_INT(_net_inet_ip, OID_AUTO, dispatch_recheck_count, CTLFLAG_RW, 217 &ip_dispatch_recheck, 0, ""); 218 219 static struct lwkt_token ipq_token = LWKT_TOKEN_MP_INITIALIZER(ipq_token); 220 221 #ifdef DIAGNOSTIC 222 static int ipprintfs = 0; 223 #endif 224 225 extern struct domain inetdomain; 226 extern struct protosw inetsw[]; 227 u_char ip_protox[IPPROTO_MAX]; 228 struct in_ifaddrhead in_ifaddrheads[MAXCPU]; /* first inet address */ 229 struct in_ifaddrhashhead *in_ifaddrhashtbls[MAXCPU]; 230 /* inet addr hash table */ 231 u_long in_ifaddrhmask; /* mask for hash table */ 232 233 struct ip_stats ipstats_percpu[MAXCPU]; 234 #ifdef SMP 235 static int 236 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 237 { 238 int cpu, error = 0; 239 240 for (cpu = 0; cpu < ncpus; ++cpu) { 241 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu], 242 sizeof(struct ip_stats)))) 243 break; 244 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu], 245 sizeof(struct ip_stats)))) 246 break; 247 } 248 249 return (error); 250 } 251 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 252 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 253 #else 254 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 255 &ipstat, ip_stats, "IP statistics"); 256 #endif 257 258 /* Packet reassembly stuff */ 259 #define IPREASS_NHASH_LOG2 6 260 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 261 #define IPREASS_HMASK (IPREASS_NHASH - 1) 262 #define IPREASS_HASH(x,y) \ 263 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 264 265 static struct ipq ipq[IPREASS_NHASH]; 266 267 #ifdef IPCTL_DEFMTU 268 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 269 &ip_mtu, 0, "Default MTU"); 270 #endif 271 272 #ifdef IPSTEALTH 273 static int ipstealth = 0; 274 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, ""); 275 #else 276 static const int ipstealth = 0; 277 #endif 278 279 struct mbuf *(*ip_divert_p)(struct mbuf *, int, int); 280 281 struct pfil_head inet_pfil_hook; 282 283 /* 284 * struct ip_srcrt_opt is used to store packet state while it travels 285 * through the stack. 286 * 287 * XXX Note that the code even makes assumptions on the size and 288 * alignment of fields inside struct ip_srcrt so e.g. adding some 289 * fields will break the code. This needs to be fixed. 290 * 291 * We need to save the IP options in case a protocol wants to respond 292 * to an incoming packet over the same route if the packet got here 293 * using IP source routing. This allows connection establishment and 294 * maintenance when the remote end is on a network that is not known 295 * to us. 296 */ 297 struct ip_srcrt { 298 struct in_addr dst; /* final destination */ 299 char nop; /* one NOP to align */ 300 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 301 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 302 }; 303 304 struct ip_srcrt_opt { 305 int ip_nhops; 306 struct ip_srcrt ip_srcrt; 307 }; 308 309 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 310 static struct malloc_pipe ipq_mpipe; 311 312 static void save_rte(struct mbuf *, u_char *, struct in_addr); 313 static int ip_dooptions(struct mbuf *m, int, struct sockaddr_in *); 314 static void ip_freef(struct ipq *); 315 static void ip_input_handler(struct netmsg *); 316 317 /* 318 * IP initialization: fill in IP protocol switch table. 319 * All protocols not implemented in kernel go to raw IP protocol handler. 320 */ 321 void 322 ip_init(void) 323 { 324 struct protosw *pr; 325 int i; 326 #ifdef SMP 327 int cpu; 328 #endif 329 330 /* 331 * Make sure we can handle a reasonable number of fragments but 332 * cap it at 4000 (XXX). 333 */ 334 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 335 IFQ_MAXLEN, 4000, 0, NULL); 336 for (i = 0; i < ncpus; ++i) { 337 TAILQ_INIT(&in_ifaddrheads[i]); 338 in_ifaddrhashtbls[i] = 339 hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 340 } 341 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 342 if (pr == NULL) 343 panic("ip_init"); 344 for (i = 0; i < IPPROTO_MAX; i++) 345 ip_protox[i] = pr - inetsw; 346 for (pr = inetdomain.dom_protosw; 347 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 348 if (pr->pr_domain->dom_family == PF_INET && pr->pr_protocol) { 349 if (pr->pr_protocol != IPPROTO_RAW) 350 ip_protox[pr->pr_protocol] = pr - inetsw; 351 } 352 } 353 354 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 355 inet_pfil_hook.ph_af = AF_INET; 356 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) { 357 kprintf("%s: WARNING: unable to register pfil hook, " 358 "error %d\n", __func__, i); 359 } 360 361 for (i = 0; i < IPREASS_NHASH; i++) 362 ipq[i].next = ipq[i].prev = &ipq[i]; 363 364 maxnipq = nmbclusters / 32; 365 maxfragsperpacket = 16; 366 367 ip_id = time_second & 0xffff; 368 369 /* 370 * Initialize IP statistics counters for each CPU. 371 * 372 */ 373 #ifdef SMP 374 for (cpu = 0; cpu < ncpus; ++cpu) { 375 bzero(&ipstats_percpu[cpu], sizeof(struct ip_stats)); 376 } 377 #else 378 bzero(&ipstat, sizeof(struct ip_stats)); 379 #endif 380 381 netisr_register(NETISR_IP, ip_input_handler, ip_cpufn_in); 382 } 383 384 /* Do transport protocol processing. */ 385 static void 386 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip) 387 { 388 const struct protosw *pr = &inetsw[ip_protox[ip->ip_p]]; 389 390 /* 391 * Switch out to protocol's input routine. 392 */ 393 PR_GET_MPLOCK(pr); 394 pr->pr_input(m, hlen, ip->ip_p); 395 PR_REL_MPLOCK(pr); 396 } 397 398 static void 399 transport_processing_handler(netmsg_t netmsg) 400 { 401 struct netmsg_packet *pmsg = (struct netmsg_packet *)netmsg; 402 struct ip *ip; 403 int hlen; 404 405 ip = mtod(pmsg->nm_packet, struct ip *); 406 hlen = pmsg->nm_netmsg.nm_lmsg.u.ms_result; 407 408 transport_processing_oncpu(pmsg->nm_packet, hlen, ip); 409 /* netmsg was embedded in the mbuf, do not reply! */ 410 } 411 412 static void 413 ip_input_handler(struct netmsg *msg0) 414 { 415 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet; 416 417 ip_input(m); 418 /* msg0 was embedded in the mbuf, do not reply! */ 419 } 420 421 /* 422 * IP input routine. Checksum and byte swap header. If fragmented 423 * try to reassemble. Process options. Pass to next level. 424 */ 425 void 426 ip_input(struct mbuf *m) 427 { 428 struct ip *ip; 429 struct in_ifaddr *ia = NULL; 430 struct in_ifaddr_container *iac; 431 int hlen, checkif; 432 u_short sum; 433 struct in_addr pkt_dst; 434 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 435 struct in_addr odst; /* original dst address(NAT) */ 436 struct m_tag *mtag; 437 struct sockaddr_in *next_hop = NULL; 438 lwkt_port_t port; 439 #ifdef FAST_IPSEC 440 struct tdb_ident *tdbi; 441 struct secpolicy *sp; 442 int error; 443 #endif 444 445 M_ASSERTPKTHDR(m); 446 447 /* 448 * This routine is called from numerous places which may not have 449 * characterized the packet. 450 */ 451 if ((m->m_flags & M_HASH) == 0) { 452 ++ip_dispatch_software; 453 ip_cpufn(&m, 0, IP_MPORT_IN); 454 if (m == NULL) 455 return; 456 KKASSERT(m->m_flags & M_HASH); 457 } 458 ip = mtod(m, struct ip *); 459 460 /* 461 * Pull out certain tags 462 */ 463 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 464 /* Next hop */ 465 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 466 KKASSERT(mtag != NULL); 467 next_hop = m_tag_data(mtag); 468 } 469 470 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 471 /* dummynet already filtered us */ 472 ip = mtod(m, struct ip *); 473 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 474 goto iphack; 475 } 476 477 ipstat.ips_total++; 478 479 /* length checks already done in ip_cpufn() */ 480 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); 481 482 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 483 ipstat.ips_badvers++; 484 goto bad; 485 } 486 487 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 488 /* length checks already done in ip_cpufn() */ 489 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 490 KASSERT(m->m_len >= hlen, ("complete IP header not in one mbuf")); 491 492 /* 127/8 must not appear on wire - RFC1122 */ 493 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 494 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 495 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 496 ipstat.ips_badaddr++; 497 goto bad; 498 } 499 } 500 501 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 502 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 503 } else { 504 if (hlen == sizeof(struct ip)) 505 sum = in_cksum_hdr(ip); 506 else 507 sum = in_cksum(m, hlen); 508 } 509 if (sum != 0) { 510 ipstat.ips_badsum++; 511 goto bad; 512 } 513 514 #ifdef ALTQ 515 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 516 /* packet is dropped by traffic conditioner */ 517 return; 518 } 519 #endif 520 /* 521 * Convert fields to host representation. 522 */ 523 ip->ip_len = ntohs(ip->ip_len); 524 ip->ip_off = ntohs(ip->ip_off); 525 526 /* length checks already done in ip_cpufn() */ 527 KASSERT(ip->ip_len >= hlen, ("total length less then header length")); 528 KASSERT(m->m_pkthdr.len >= ip->ip_len, ("mbuf too short")); 529 530 /* 531 * Trim mbufs if longer than the IP header would have us expect. 532 */ 533 if (m->m_pkthdr.len > ip->ip_len) { 534 if (m->m_len == m->m_pkthdr.len) { 535 m->m_len = ip->ip_len; 536 m->m_pkthdr.len = ip->ip_len; 537 } else { 538 m_adj(m, ip->ip_len - m->m_pkthdr.len); 539 } 540 } 541 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 542 /* 543 * Bypass packet filtering for packets from a tunnel (gif). 544 */ 545 if (ipsec_gethist(m, NULL)) 546 goto pass; 547 #endif 548 549 /* 550 * IpHack's section. 551 * Right now when no processing on packet has done 552 * and it is still fresh out of network we do our black 553 * deals with it. 554 * - Firewall: deny/allow/divert 555 * - Xlate: translate packet's addr/port (NAT). 556 * - Pipe: pass pkt through dummynet. 557 * - Wrap: fake packet's addr/port <unimpl.> 558 * - Encapsulate: put it in another IP and send out. <unimp.> 559 */ 560 561 iphack: 562 /* 563 * If we've been forwarded from the output side, then 564 * skip the firewall a second time 565 */ 566 if (next_hop != NULL) 567 goto ours; 568 569 /* No pfil hooks */ 570 if (!pfil_has_hooks(&inet_pfil_hook)) { 571 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 572 /* 573 * Strip dummynet tags from stranded packets 574 */ 575 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL); 576 KKASSERT(mtag != NULL); 577 m_tag_delete(m, mtag); 578 m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED; 579 } 580 goto pass; 581 } 582 583 /* 584 * Run through list of hooks for input packets. 585 * 586 * NOTE! If the packet is rewritten pf/ipfw/whoever must 587 * clear M_HASH. 588 */ 589 odst = ip->ip_dst; 590 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN)) 591 return; 592 if (m == NULL) /* consumed by filter */ 593 return; 594 ip = mtod(m, struct ip *); 595 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 596 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 597 598 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 599 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 600 KKASSERT(mtag != NULL); 601 next_hop = m_tag_data(mtag); 602 } 603 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 604 ip_dn_queue(m); 605 return; 606 } 607 if (m->m_pkthdr.fw_flags & FW_MBUF_REDISPATCH) { 608 m->m_pkthdr.fw_flags &= ~FW_MBUF_REDISPATCH; 609 } 610 pass: 611 /* 612 * Process options and, if not destined for us, 613 * ship it on. ip_dooptions returns 1 when an 614 * error was detected (causing an icmp message 615 * to be sent and the original packet to be freed). 616 */ 617 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, next_hop)) 618 return; 619 620 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 621 * matter if it is destined to another node, or whether it is 622 * a multicast one, RSVP wants it! and prevents it from being forwarded 623 * anywhere else. Also checks if the rsvp daemon is running before 624 * grabbing the packet. 625 */ 626 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 627 goto ours; 628 629 /* 630 * Check our list of addresses, to see if the packet is for us. 631 * If we don't have any addresses, assume any unicast packet 632 * we receive might be for us (and let the upper layers deal 633 * with it). 634 */ 635 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) && 636 !(m->m_flags & (M_MCAST | M_BCAST))) 637 goto ours; 638 639 /* 640 * Cache the destination address of the packet; this may be 641 * changed by use of 'ipfw fwd'. 642 */ 643 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 644 645 /* 646 * Enable a consistency check between the destination address 647 * and the arrival interface for a unicast packet (the RFC 1122 648 * strong ES model) if IP forwarding is disabled and the packet 649 * is not locally generated and the packet is not subject to 650 * 'ipfw fwd'. 651 * 652 * XXX - Checking also should be disabled if the destination 653 * address is ipnat'ed to a different interface. 654 * 655 * XXX - Checking is incompatible with IP aliases added 656 * to the loopback interface instead of the interface where 657 * the packets are received. 658 */ 659 checkif = ip_checkinterface && 660 !ipforwarding && 661 m->m_pkthdr.rcvif != NULL && 662 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 663 next_hop == NULL; 664 665 /* 666 * Check for exact addresses in the hash bucket. 667 */ 668 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 669 ia = iac->ia; 670 671 /* 672 * If the address matches, verify that the packet 673 * arrived via the correct interface if checking is 674 * enabled. 675 */ 676 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 677 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 678 goto ours; 679 } 680 ia = NULL; 681 682 /* 683 * Check for broadcast addresses. 684 * 685 * Only accept broadcast packets that arrive via the matching 686 * interface. Reception of forwarded directed broadcasts would 687 * be handled via ip_forward() and ether_output() with the loopback 688 * into the stack for SIMPLEX interfaces handled by ether_output(). 689 */ 690 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 691 struct ifaddr_container *ifac; 692 693 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 694 ifa_link) { 695 struct ifaddr *ifa = ifac->ifa; 696 697 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 698 continue; 699 if (ifa->ifa_addr->sa_family != AF_INET) 700 continue; 701 ia = ifatoia(ifa); 702 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 703 pkt_dst.s_addr) 704 goto ours; 705 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 706 goto ours; 707 #ifdef BOOTP_COMPAT 708 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 709 goto ours; 710 #endif 711 } 712 } 713 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 714 struct in_multi *inm; 715 716 /* XXX Multicast is not MPSAFE yet */ 717 get_mplock(); 718 719 if (ip_mrouter != NULL) { 720 /* 721 * If we are acting as a multicast router, all 722 * incoming multicast packets are passed to the 723 * kernel-level multicast forwarding function. 724 * The packet is returned (relatively) intact; if 725 * ip_mforward() returns a non-zero value, the packet 726 * must be discarded, else it may be accepted below. 727 */ 728 if (ip_mforward != NULL && 729 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 730 rel_mplock(); 731 ipstat.ips_cantforward++; 732 m_freem(m); 733 return; 734 } 735 736 /* 737 * The process-level routing daemon needs to receive 738 * all multicast IGMP packets, whether or not this 739 * host belongs to their destination groups. 740 */ 741 if (ip->ip_p == IPPROTO_IGMP) { 742 rel_mplock(); 743 goto ours; 744 } 745 ipstat.ips_forward++; 746 } 747 /* 748 * See if we belong to the destination multicast group on the 749 * arrival interface. 750 */ 751 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 752 if (inm == NULL) { 753 rel_mplock(); 754 ipstat.ips_notmember++; 755 m_freem(m); 756 return; 757 } 758 759 rel_mplock(); 760 goto ours; 761 } 762 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 763 goto ours; 764 if (ip->ip_dst.s_addr == INADDR_ANY) 765 goto ours; 766 767 /* 768 * FAITH(Firewall Aided Internet Translator) 769 */ 770 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 771 if (ip_keepfaith) { 772 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 773 goto ours; 774 } 775 m_freem(m); 776 return; 777 } 778 779 /* 780 * Not for us; forward if possible and desirable. 781 */ 782 if (!ipforwarding) { 783 ipstat.ips_cantforward++; 784 m_freem(m); 785 } else { 786 #ifdef IPSEC 787 /* 788 * Enforce inbound IPsec SPD. 789 */ 790 if (ipsec4_in_reject(m, NULL)) { 791 ipsecstat.in_polvio++; 792 goto bad; 793 } 794 #endif 795 #ifdef FAST_IPSEC 796 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 797 crit_enter(); 798 if (mtag != NULL) { 799 tdbi = (struct tdb_ident *)m_tag_data(mtag); 800 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 801 } else { 802 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 803 IP_FORWARDING, &error); 804 } 805 if (sp == NULL) { /* NB: can happen if error */ 806 crit_exit(); 807 /*XXX error stat???*/ 808 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 809 goto bad; 810 } 811 812 /* 813 * Check security policy against packet attributes. 814 */ 815 error = ipsec_in_reject(sp, m); 816 KEY_FREESP(&sp); 817 crit_exit(); 818 if (error) { 819 ipstat.ips_cantforward++; 820 goto bad; 821 } 822 #endif 823 ip_forward(m, using_srcrt, next_hop); 824 } 825 return; 826 827 ours: 828 829 /* 830 * IPSTEALTH: Process non-routing options only 831 * if the packet is destined for us. 832 */ 833 if (ipstealth && 834 hlen > sizeof(struct ip) && 835 ip_dooptions(m, 1, next_hop)) 836 return; 837 838 /* Count the packet in the ip address stats */ 839 if (ia != NULL) { 840 ia->ia_ifa.if_ipackets++; 841 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 842 } 843 844 /* 845 * If offset or IP_MF are set, must reassemble. 846 * Otherwise, nothing need be done. 847 * (We could look in the reassembly queue to see 848 * if the packet was previously fragmented, 849 * but it's not worth the time; just let them time out.) 850 */ 851 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 852 /* 853 * Attempt reassembly; if it succeeds, proceed. ip_reass() 854 * will return a different mbuf. 855 * 856 * NOTE: ip_reass() returns m with M_HASH cleared to force 857 * us to recharacterize the packet. 858 */ 859 m = ip_reass(m); 860 if (m == NULL) 861 return; 862 ip = mtod(m, struct ip *); 863 864 /* Get the header length of the reassembled packet */ 865 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 866 } else { 867 ip->ip_len -= hlen; 868 } 869 870 #ifdef IPSEC 871 /* 872 * enforce IPsec policy checking if we are seeing last header. 873 * note that we do not visit this with protocols with pcb layer 874 * code - like udp/tcp/raw ip. 875 */ 876 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 877 ipsec4_in_reject(m, NULL)) { 878 ipsecstat.in_polvio++; 879 goto bad; 880 } 881 #endif 882 #if FAST_IPSEC 883 /* 884 * enforce IPsec policy checking if we are seeing last header. 885 * note that we do not visit this with protocols with pcb layer 886 * code - like udp/tcp/raw ip. 887 */ 888 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 889 /* 890 * Check if the packet has already had IPsec processing 891 * done. If so, then just pass it along. This tag gets 892 * set during AH, ESP, etc. input handling, before the 893 * packet is returned to the ip input queue for delivery. 894 */ 895 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 896 crit_enter(); 897 if (mtag != NULL) { 898 tdbi = (struct tdb_ident *)m_tag_data(mtag); 899 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 900 } else { 901 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 902 IP_FORWARDING, &error); 903 } 904 if (sp != NULL) { 905 /* 906 * Check security policy against packet attributes. 907 */ 908 error = ipsec_in_reject(sp, m); 909 KEY_FREESP(&sp); 910 } else { 911 /* XXX error stat??? */ 912 error = EINVAL; 913 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 914 goto bad; 915 } 916 crit_exit(); 917 if (error) 918 goto bad; 919 } 920 #endif /* FAST_IPSEC */ 921 922 /* 923 * We must forward the packet to the correct protocol thread if 924 * we are not already in it. 925 * 926 * NOTE: ip_len is now in host form. ip_len is not adjusted 927 * further for protocol processing, instead we pass hlen 928 * to the protosw and let it deal with it. 929 */ 930 ipstat.ips_delivered++; 931 932 if ((m->m_flags & M_HASH) == 0) { 933 ++ip_dispatch_recheck; 934 ip->ip_len = htons(ip->ip_len); 935 ip->ip_off = htons(ip->ip_off); 936 937 ip_cpufn(&m, 0, IP_MPORT_IN); 938 if (m == NULL) 939 return; 940 941 ip = mtod(m, struct ip *); 942 ip->ip_len = ntohs(ip->ip_len); 943 ip->ip_off = ntohs(ip->ip_off); 944 KKASSERT(m->m_flags & M_HASH); 945 } 946 port = cpu_portfn(m->m_pkthdr.hash); 947 948 if (port != &curthread->td_msgport) { 949 struct netmsg_packet *pmsg; 950 951 ++ip_dispatch_slow; 952 953 pmsg = &m->m_hdr.mh_netmsg; 954 netmsg_init(&pmsg->nm_netmsg, NULL, &netisr_apanic_rport, 955 0, transport_processing_handler); 956 pmsg->nm_packet = m; 957 pmsg->nm_netmsg.nm_lmsg.u.ms_result = hlen; 958 959 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg); 960 } else { 961 ++ip_dispatch_fast; 962 transport_processing_oncpu(m, hlen, ip); 963 } 964 return; 965 966 bad: 967 m_freem(m); 968 } 969 970 /* 971 * Take incoming datagram fragment and try to reassemble it into 972 * whole datagram. If a chain for reassembly of this datagram already 973 * exists, then it is given as fp; otherwise have to make a chain. 974 */ 975 struct mbuf * 976 ip_reass(struct mbuf *m) 977 { 978 struct ip *ip = mtod(m, struct ip *); 979 struct mbuf *p = NULL, *q, *nq; 980 struct mbuf *n; 981 struct ipq *fp = NULL; 982 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 983 int i, next; 984 u_short sum; 985 986 /* If maxnipq is 0, never accept fragments. */ 987 if (maxnipq == 0) { 988 ipstat.ips_fragments++; 989 ipstat.ips_fragdropped++; 990 m_freem(m); 991 return NULL; 992 } 993 994 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 995 /* 996 * Look for queue of fragments of this datagram. 997 */ 998 lwkt_gettoken(&ipq_token); 999 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) { 1000 if (ip->ip_id == fp->ipq_id && 1001 ip->ip_src.s_addr == fp->ipq_src.s_addr && 1002 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 1003 ip->ip_p == fp->ipq_p) 1004 goto found; 1005 } 1006 1007 fp = NULL; 1008 1009 /* 1010 * Enforce upper bound on number of fragmented packets 1011 * for which we attempt reassembly; 1012 * If maxnipq is -1, accept all fragments without limitation. 1013 */ 1014 if (nipq > maxnipq && maxnipq > 0) { 1015 /* 1016 * drop something from the tail of the current queue 1017 * before proceeding further 1018 */ 1019 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 1020 for (i = 0; i < IPREASS_NHASH; i++) { 1021 if (ipq[i].prev != &ipq[i]) { 1022 ipstat.ips_fragtimeout += 1023 ipq[i].prev->ipq_nfrags; 1024 ip_freef(ipq[i].prev); 1025 break; 1026 } 1027 } 1028 } else { 1029 ipstat.ips_fragtimeout += 1030 ipq[sum].prev->ipq_nfrags; 1031 ip_freef(ipq[sum].prev); 1032 } 1033 } 1034 found: 1035 /* 1036 * Adjust ip_len to not reflect header, 1037 * convert offset of this to bytes. 1038 */ 1039 ip->ip_len -= hlen; 1040 if (ip->ip_off & IP_MF) { 1041 /* 1042 * Make sure that fragments have a data length 1043 * that's a non-zero multiple of 8 bytes. 1044 */ 1045 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 1046 ipstat.ips_toosmall++; /* XXX */ 1047 m_freem(m); 1048 goto done; 1049 } 1050 m->m_flags |= M_FRAG; 1051 } else { 1052 m->m_flags &= ~M_FRAG; 1053 } 1054 ip->ip_off <<= 3; 1055 1056 ipstat.ips_fragments++; 1057 m->m_pkthdr.header = ip; 1058 1059 /* 1060 * If the hardware has not done csum over this fragment 1061 * then csum_data is not valid at all. 1062 */ 1063 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) 1064 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) { 1065 m->m_pkthdr.csum_data = 0; 1066 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR); 1067 } 1068 1069 /* 1070 * Presence of header sizes in mbufs 1071 * would confuse code below. 1072 */ 1073 m->m_data += hlen; 1074 m->m_len -= hlen; 1075 1076 /* 1077 * If first fragment to arrive, create a reassembly queue. 1078 */ 1079 if (fp == NULL) { 1080 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1081 goto dropfrag; 1082 insque(fp, &ipq[sum]); 1083 nipq++; 1084 fp->ipq_nfrags = 1; 1085 fp->ipq_ttl = IPFRAGTTL; 1086 fp->ipq_p = ip->ip_p; 1087 fp->ipq_id = ip->ip_id; 1088 fp->ipq_src = ip->ip_src; 1089 fp->ipq_dst = ip->ip_dst; 1090 fp->ipq_frags = m; 1091 m->m_nextpkt = NULL; 1092 goto inserted; 1093 } else { 1094 fp->ipq_nfrags++; 1095 } 1096 1097 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1098 1099 /* 1100 * Find a segment which begins after this one does. 1101 */ 1102 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1103 if (GETIP(q)->ip_off > ip->ip_off) 1104 break; 1105 } 1106 1107 /* 1108 * If there is a preceding segment, it may provide some of 1109 * our data already. If so, drop the data from the incoming 1110 * segment. If it provides all of our data, drop us, otherwise 1111 * stick new segment in the proper place. 1112 * 1113 * If some of the data is dropped from the the preceding 1114 * segment, then it's checksum is invalidated. 1115 */ 1116 if (p) { 1117 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1118 if (i > 0) { 1119 if (i >= ip->ip_len) 1120 goto dropfrag; 1121 m_adj(m, i); 1122 m->m_pkthdr.csum_flags = 0; 1123 ip->ip_off += i; 1124 ip->ip_len -= i; 1125 } 1126 m->m_nextpkt = p->m_nextpkt; 1127 p->m_nextpkt = m; 1128 } else { 1129 m->m_nextpkt = fp->ipq_frags; 1130 fp->ipq_frags = m; 1131 } 1132 1133 /* 1134 * While we overlap succeeding segments trim them or, 1135 * if they are completely covered, dequeue them. 1136 */ 1137 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1138 q = nq) { 1139 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1140 if (i < GETIP(q)->ip_len) { 1141 GETIP(q)->ip_len -= i; 1142 GETIP(q)->ip_off += i; 1143 m_adj(q, i); 1144 q->m_pkthdr.csum_flags = 0; 1145 break; 1146 } 1147 nq = q->m_nextpkt; 1148 m->m_nextpkt = nq; 1149 ipstat.ips_fragdropped++; 1150 fp->ipq_nfrags--; 1151 q->m_nextpkt = NULL; 1152 m_freem(q); 1153 } 1154 1155 inserted: 1156 /* 1157 * Check for complete reassembly and perform frag per packet 1158 * limiting. 1159 * 1160 * Frag limiting is performed here so that the nth frag has 1161 * a chance to complete the packet before we drop the packet. 1162 * As a result, n+1 frags are actually allowed per packet, but 1163 * only n will ever be stored. (n = maxfragsperpacket.) 1164 * 1165 */ 1166 next = 0; 1167 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1168 if (GETIP(q)->ip_off != next) { 1169 if (fp->ipq_nfrags > maxfragsperpacket) { 1170 ipstat.ips_fragdropped += fp->ipq_nfrags; 1171 ip_freef(fp); 1172 } 1173 goto done; 1174 } 1175 next += GETIP(q)->ip_len; 1176 } 1177 /* Make sure the last packet didn't have the IP_MF flag */ 1178 if (p->m_flags & M_FRAG) { 1179 if (fp->ipq_nfrags > maxfragsperpacket) { 1180 ipstat.ips_fragdropped += fp->ipq_nfrags; 1181 ip_freef(fp); 1182 } 1183 goto done; 1184 } 1185 1186 /* 1187 * Reassembly is complete. Make sure the packet is a sane size. 1188 */ 1189 q = fp->ipq_frags; 1190 ip = GETIP(q); 1191 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1192 ipstat.ips_toolong++; 1193 ipstat.ips_fragdropped += fp->ipq_nfrags; 1194 ip_freef(fp); 1195 goto done; 1196 } 1197 1198 /* 1199 * Concatenate fragments. 1200 */ 1201 m = q; 1202 n = m->m_next; 1203 m->m_next = NULL; 1204 m_cat(m, n); 1205 nq = q->m_nextpkt; 1206 q->m_nextpkt = NULL; 1207 for (q = nq; q != NULL; q = nq) { 1208 nq = q->m_nextpkt; 1209 q->m_nextpkt = NULL; 1210 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1211 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1212 m_cat(m, q); 1213 } 1214 1215 /* 1216 * Clean up the 1's complement checksum. Carry over 16 bits must 1217 * be added back. This assumes no more then 65535 packet fragments 1218 * were reassembled. A second carry can also occur (but not a third). 1219 */ 1220 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + 1221 (m->m_pkthdr.csum_data >> 16); 1222 if (m->m_pkthdr.csum_data > 0xFFFF) 1223 m->m_pkthdr.csum_data -= 0xFFFF; 1224 1225 /* 1226 * Create header for new ip packet by 1227 * modifying header of first packet; 1228 * dequeue and discard fragment reassembly header. 1229 * Make header visible. 1230 */ 1231 ip->ip_len = next; 1232 ip->ip_src = fp->ipq_src; 1233 ip->ip_dst = fp->ipq_dst; 1234 remque(fp); 1235 nipq--; 1236 mpipe_free(&ipq_mpipe, fp); 1237 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1238 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1239 /* some debugging cruft by sklower, below, will go away soon */ 1240 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1241 int plen = 0; 1242 1243 for (n = m; n; n = n->m_next) 1244 plen += n->m_len; 1245 m->m_pkthdr.len = plen; 1246 } 1247 1248 /* 1249 * Reassembly complete, return the next protocol. 1250 * 1251 * Be sure to clear M_HASH to force the packet 1252 * to be re-characterized. 1253 * 1254 * Clear M_FRAG, we are no longer a fragment. 1255 */ 1256 m->m_flags &= ~(M_HASH | M_FRAG); 1257 1258 ipstat.ips_reassembled++; 1259 lwkt_reltoken(&ipq_token); 1260 return (m); 1261 1262 dropfrag: 1263 ipstat.ips_fragdropped++; 1264 if (fp != NULL) 1265 fp->ipq_nfrags--; 1266 m_freem(m); 1267 done: 1268 lwkt_reltoken(&ipq_token); 1269 return (NULL); 1270 1271 #undef GETIP 1272 } 1273 1274 /* 1275 * Free a fragment reassembly header and all 1276 * associated datagrams. 1277 * 1278 * Called with ipq_token held. 1279 */ 1280 static void 1281 ip_freef(struct ipq *fp) 1282 { 1283 struct mbuf *q; 1284 1285 /* 1286 * Remove first to protect against blocking 1287 */ 1288 remque(fp); 1289 1290 /* 1291 * Clean out at our leisure 1292 */ 1293 while (fp->ipq_frags) { 1294 q = fp->ipq_frags; 1295 fp->ipq_frags = q->m_nextpkt; 1296 q->m_nextpkt = NULL; 1297 m_freem(q); 1298 } 1299 mpipe_free(&ipq_mpipe, fp); 1300 nipq--; 1301 } 1302 1303 /* 1304 * IP timer processing; 1305 * if a timer expires on a reassembly 1306 * queue, discard it. 1307 */ 1308 void 1309 ip_slowtimo(void) 1310 { 1311 struct ipq *fp; 1312 int i; 1313 1314 lwkt_gettoken(&ipq_token); 1315 for (i = 0; i < IPREASS_NHASH; i++) { 1316 fp = ipq[i].next; 1317 if (fp == NULL) 1318 continue; 1319 while (fp != &ipq[i]) { 1320 --fp->ipq_ttl; 1321 fp = fp->next; 1322 if (fp->prev->ipq_ttl == 0) { 1323 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1324 ip_freef(fp->prev); 1325 } 1326 } 1327 } 1328 /* 1329 * If we are over the maximum number of fragments 1330 * (due to the limit being lowered), drain off 1331 * enough to get down to the new limit. 1332 */ 1333 if (maxnipq >= 0 && nipq > maxnipq) { 1334 for (i = 0; i < IPREASS_NHASH; i++) { 1335 while (nipq > maxnipq && 1336 (ipq[i].next != &ipq[i])) { 1337 ipstat.ips_fragdropped += 1338 ipq[i].next->ipq_nfrags; 1339 ip_freef(ipq[i].next); 1340 } 1341 } 1342 } 1343 lwkt_reltoken(&ipq_token); 1344 ipflow_slowtimo(); 1345 } 1346 1347 /* 1348 * Drain off all datagram fragments. 1349 */ 1350 void 1351 ip_drain(void) 1352 { 1353 int i; 1354 1355 lwkt_gettoken(&ipq_token); 1356 for (i = 0; i < IPREASS_NHASH; i++) { 1357 while (ipq[i].next != &ipq[i]) { 1358 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1359 ip_freef(ipq[i].next); 1360 } 1361 } 1362 lwkt_reltoken(&ipq_token); 1363 in_rtqdrain(); 1364 } 1365 1366 /* 1367 * Do option processing on a datagram, 1368 * possibly discarding it if bad options are encountered, 1369 * or forwarding it if source-routed. 1370 * The pass argument is used when operating in the IPSTEALTH 1371 * mode to tell what options to process: 1372 * [LS]SRR (pass 0) or the others (pass 1). 1373 * The reason for as many as two passes is that when doing IPSTEALTH, 1374 * non-routing options should be processed only if the packet is for us. 1375 * Returns 1 if packet has been forwarded/freed, 1376 * 0 if the packet should be processed further. 1377 */ 1378 static int 1379 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1380 { 1381 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1382 struct ip *ip = mtod(m, struct ip *); 1383 u_char *cp; 1384 struct in_ifaddr *ia; 1385 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1386 boolean_t forward = FALSE; 1387 struct in_addr *sin, dst; 1388 n_time ntime; 1389 1390 dst = ip->ip_dst; 1391 cp = (u_char *)(ip + 1); 1392 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1393 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1394 opt = cp[IPOPT_OPTVAL]; 1395 if (opt == IPOPT_EOL) 1396 break; 1397 if (opt == IPOPT_NOP) 1398 optlen = 1; 1399 else { 1400 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1401 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1402 goto bad; 1403 } 1404 optlen = cp[IPOPT_OLEN]; 1405 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1406 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1407 goto bad; 1408 } 1409 } 1410 switch (opt) { 1411 1412 default: 1413 break; 1414 1415 /* 1416 * Source routing with record. 1417 * Find interface with current destination address. 1418 * If none on this machine then drop if strictly routed, 1419 * or do nothing if loosely routed. 1420 * Record interface address and bring up next address 1421 * component. If strictly routed make sure next 1422 * address is on directly accessible net. 1423 */ 1424 case IPOPT_LSRR: 1425 case IPOPT_SSRR: 1426 if (ipstealth && pass > 0) 1427 break; 1428 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1429 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1430 goto bad; 1431 } 1432 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1433 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1434 goto bad; 1435 } 1436 ipaddr.sin_addr = ip->ip_dst; 1437 ia = (struct in_ifaddr *) 1438 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1439 if (ia == NULL) { 1440 if (opt == IPOPT_SSRR) { 1441 type = ICMP_UNREACH; 1442 code = ICMP_UNREACH_SRCFAIL; 1443 goto bad; 1444 } 1445 if (!ip_dosourceroute) 1446 goto nosourcerouting; 1447 /* 1448 * Loose routing, and not at next destination 1449 * yet; nothing to do except forward. 1450 */ 1451 break; 1452 } 1453 off--; /* 0 origin */ 1454 if (off > optlen - (int)sizeof(struct in_addr)) { 1455 /* 1456 * End of source route. Should be for us. 1457 */ 1458 if (!ip_acceptsourceroute) 1459 goto nosourcerouting; 1460 save_rte(m, cp, ip->ip_src); 1461 break; 1462 } 1463 if (ipstealth) 1464 goto dropit; 1465 if (!ip_dosourceroute) { 1466 if (ipforwarding) { 1467 char buf[sizeof "aaa.bbb.ccc.ddd"]; 1468 1469 /* 1470 * Acting as a router, so generate ICMP 1471 */ 1472 nosourcerouting: 1473 strcpy(buf, inet_ntoa(ip->ip_dst)); 1474 log(LOG_WARNING, 1475 "attempted source route from %s to %s\n", 1476 inet_ntoa(ip->ip_src), buf); 1477 type = ICMP_UNREACH; 1478 code = ICMP_UNREACH_SRCFAIL; 1479 goto bad; 1480 } else { 1481 /* 1482 * Not acting as a router, 1483 * so silently drop. 1484 */ 1485 dropit: 1486 ipstat.ips_cantforward++; 1487 m_freem(m); 1488 return (1); 1489 } 1490 } 1491 1492 /* 1493 * locate outgoing interface 1494 */ 1495 memcpy(&ipaddr.sin_addr, cp + off, 1496 sizeof ipaddr.sin_addr); 1497 1498 if (opt == IPOPT_SSRR) { 1499 #define INA struct in_ifaddr * 1500 #define SA struct sockaddr * 1501 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1502 == NULL) 1503 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1504 } else { 1505 ia = ip_rtaddr(ipaddr.sin_addr, NULL); 1506 } 1507 if (ia == NULL) { 1508 type = ICMP_UNREACH; 1509 code = ICMP_UNREACH_SRCFAIL; 1510 goto bad; 1511 } 1512 ip->ip_dst = ipaddr.sin_addr; 1513 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1514 sizeof(struct in_addr)); 1515 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1516 /* 1517 * Let ip_intr's mcast routing check handle mcast pkts 1518 */ 1519 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1520 break; 1521 1522 case IPOPT_RR: 1523 if (ipstealth && pass == 0) 1524 break; 1525 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1526 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1527 goto bad; 1528 } 1529 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1530 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1531 goto bad; 1532 } 1533 /* 1534 * If no space remains, ignore. 1535 */ 1536 off--; /* 0 origin */ 1537 if (off > optlen - (int)sizeof(struct in_addr)) 1538 break; 1539 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1540 sizeof ipaddr.sin_addr); 1541 /* 1542 * locate outgoing interface; if we're the destination, 1543 * use the incoming interface (should be same). 1544 */ 1545 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1546 (ia = ip_rtaddr(ipaddr.sin_addr, NULL)) == NULL) { 1547 type = ICMP_UNREACH; 1548 code = ICMP_UNREACH_HOST; 1549 goto bad; 1550 } 1551 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1552 sizeof(struct in_addr)); 1553 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1554 break; 1555 1556 case IPOPT_TS: 1557 if (ipstealth && pass == 0) 1558 break; 1559 code = cp - (u_char *)ip; 1560 if (optlen < 4 || optlen > 40) { 1561 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1562 goto bad; 1563 } 1564 if ((off = cp[IPOPT_OFFSET]) < 5) { 1565 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1566 goto bad; 1567 } 1568 if (off > optlen - (int)sizeof(int32_t)) { 1569 cp[IPOPT_OFFSET + 1] += (1 << 4); 1570 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1571 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1572 goto bad; 1573 } 1574 break; 1575 } 1576 off--; /* 0 origin */ 1577 sin = (struct in_addr *)(cp + off); 1578 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1579 1580 case IPOPT_TS_TSONLY: 1581 break; 1582 1583 case IPOPT_TS_TSANDADDR: 1584 if (off + sizeof(n_time) + 1585 sizeof(struct in_addr) > optlen) { 1586 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1587 goto bad; 1588 } 1589 ipaddr.sin_addr = dst; 1590 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1591 m->m_pkthdr.rcvif); 1592 if (ia == NULL) 1593 continue; 1594 memcpy(sin, &IA_SIN(ia)->sin_addr, 1595 sizeof(struct in_addr)); 1596 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1597 off += sizeof(struct in_addr); 1598 break; 1599 1600 case IPOPT_TS_PRESPEC: 1601 if (off + sizeof(n_time) + 1602 sizeof(struct in_addr) > optlen) { 1603 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1604 goto bad; 1605 } 1606 memcpy(&ipaddr.sin_addr, sin, 1607 sizeof(struct in_addr)); 1608 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1609 continue; 1610 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1611 off += sizeof(struct in_addr); 1612 break; 1613 1614 default: 1615 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1616 goto bad; 1617 } 1618 ntime = iptime(); 1619 memcpy(cp + off, &ntime, sizeof(n_time)); 1620 cp[IPOPT_OFFSET] += sizeof(n_time); 1621 } 1622 } 1623 if (forward && ipforwarding) { 1624 ip_forward(m, TRUE, next_hop); 1625 return (1); 1626 } 1627 return (0); 1628 bad: 1629 icmp_error(m, type, code, 0, 0); 1630 ipstat.ips_badoptions++; 1631 return (1); 1632 } 1633 1634 /* 1635 * Given address of next destination (final or next hop), 1636 * return internet address info of interface to be used to get there. 1637 */ 1638 struct in_ifaddr * 1639 ip_rtaddr(struct in_addr dst, struct route *ro0) 1640 { 1641 struct route sro, *ro; 1642 struct sockaddr_in *sin; 1643 struct in_ifaddr *ia; 1644 1645 if (ro0 != NULL) { 1646 ro = ro0; 1647 } else { 1648 bzero(&sro, sizeof(sro)); 1649 ro = &sro; 1650 } 1651 1652 sin = (struct sockaddr_in *)&ro->ro_dst; 1653 1654 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1655 if (ro->ro_rt != NULL) { 1656 RTFREE(ro->ro_rt); 1657 ro->ro_rt = NULL; 1658 } 1659 sin->sin_family = AF_INET; 1660 sin->sin_len = sizeof *sin; 1661 sin->sin_addr = dst; 1662 rtalloc_ign(ro, RTF_PRCLONING); 1663 } 1664 1665 if (ro->ro_rt == NULL) 1666 return (NULL); 1667 1668 ia = ifatoia(ro->ro_rt->rt_ifa); 1669 1670 if (ro == &sro) 1671 RTFREE(ro->ro_rt); 1672 return ia; 1673 } 1674 1675 /* 1676 * Save incoming source route for use in replies, 1677 * to be picked up later by ip_srcroute if the receiver is interested. 1678 */ 1679 static void 1680 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1681 { 1682 struct m_tag *mtag; 1683 struct ip_srcrt_opt *opt; 1684 unsigned olen; 1685 1686 mtag = m_tag_get(PACKET_TAG_IPSRCRT, sizeof(*opt), MB_DONTWAIT); 1687 if (mtag == NULL) 1688 return; 1689 opt = m_tag_data(mtag); 1690 1691 olen = option[IPOPT_OLEN]; 1692 #ifdef DIAGNOSTIC 1693 if (ipprintfs) 1694 kprintf("save_rte: olen %d\n", olen); 1695 #endif 1696 if (olen > sizeof(opt->ip_srcrt) - (1 + sizeof(dst))) { 1697 m_tag_free(mtag); 1698 return; 1699 } 1700 bcopy(option, opt->ip_srcrt.srcopt, olen); 1701 opt->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1702 opt->ip_srcrt.dst = dst; 1703 m_tag_prepend(m, mtag); 1704 } 1705 1706 /* 1707 * Retrieve incoming source route for use in replies, 1708 * in the same form used by setsockopt. 1709 * The first hop is placed before the options, will be removed later. 1710 */ 1711 struct mbuf * 1712 ip_srcroute(struct mbuf *m0) 1713 { 1714 struct in_addr *p, *q; 1715 struct mbuf *m; 1716 struct m_tag *mtag; 1717 struct ip_srcrt_opt *opt; 1718 1719 if (m0 == NULL) 1720 return NULL; 1721 1722 mtag = m_tag_find(m0, PACKET_TAG_IPSRCRT, NULL); 1723 if (mtag == NULL) 1724 return NULL; 1725 opt = m_tag_data(mtag); 1726 1727 if (opt->ip_nhops == 0) 1728 return (NULL); 1729 m = m_get(MB_DONTWAIT, MT_HEADER); 1730 if (m == NULL) 1731 return (NULL); 1732 1733 #define OPTSIZ (sizeof(opt->ip_srcrt.nop) + sizeof(opt->ip_srcrt.srcopt)) 1734 1735 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1736 m->m_len = opt->ip_nhops * sizeof(struct in_addr) + 1737 sizeof(struct in_addr) + OPTSIZ; 1738 #ifdef DIAGNOSTIC 1739 if (ipprintfs) { 1740 kprintf("ip_srcroute: nhops %d mlen %d", 1741 opt->ip_nhops, m->m_len); 1742 } 1743 #endif 1744 1745 /* 1746 * First save first hop for return route 1747 */ 1748 p = &opt->ip_srcrt.route[opt->ip_nhops - 1]; 1749 *(mtod(m, struct in_addr *)) = *p--; 1750 #ifdef DIAGNOSTIC 1751 if (ipprintfs) 1752 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1753 #endif 1754 1755 /* 1756 * Copy option fields and padding (nop) to mbuf. 1757 */ 1758 opt->ip_srcrt.nop = IPOPT_NOP; 1759 opt->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1760 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &opt->ip_srcrt.nop, 1761 OPTSIZ); 1762 q = (struct in_addr *)(mtod(m, caddr_t) + 1763 sizeof(struct in_addr) + OPTSIZ); 1764 #undef OPTSIZ 1765 /* 1766 * Record return path as an IP source route, 1767 * reversing the path (pointers are now aligned). 1768 */ 1769 while (p >= opt->ip_srcrt.route) { 1770 #ifdef DIAGNOSTIC 1771 if (ipprintfs) 1772 kprintf(" %x", ntohl(q->s_addr)); 1773 #endif 1774 *q++ = *p--; 1775 } 1776 /* 1777 * Last hop goes to final destination. 1778 */ 1779 *q = opt->ip_srcrt.dst; 1780 m_tag_delete(m0, mtag); 1781 #ifdef DIAGNOSTIC 1782 if (ipprintfs) 1783 kprintf(" %x\n", ntohl(q->s_addr)); 1784 #endif 1785 return (m); 1786 } 1787 1788 /* 1789 * Strip out IP options. 1790 */ 1791 void 1792 ip_stripoptions(struct mbuf *m) 1793 { 1794 int datalen; 1795 struct ip *ip = mtod(m, struct ip *); 1796 caddr_t opts; 1797 int optlen; 1798 1799 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1800 opts = (caddr_t)(ip + 1); 1801 datalen = m->m_len - (sizeof(struct ip) + optlen); 1802 bcopy(opts + optlen, opts, datalen); 1803 m->m_len -= optlen; 1804 if (m->m_flags & M_PKTHDR) 1805 m->m_pkthdr.len -= optlen; 1806 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1807 } 1808 1809 u_char inetctlerrmap[PRC_NCMDS] = { 1810 0, 0, 0, 0, 1811 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1812 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1813 EMSGSIZE, EHOSTUNREACH, 0, 0, 1814 0, 0, 0, 0, 1815 ENOPROTOOPT, ECONNREFUSED 1816 }; 1817 1818 /* 1819 * Forward a packet. If some error occurs return the sender 1820 * an icmp packet. Note we can't always generate a meaningful 1821 * icmp message because icmp doesn't have a large enough repertoire 1822 * of codes and types. 1823 * 1824 * If not forwarding, just drop the packet. This could be confusing 1825 * if ipforwarding was zero but some routing protocol was advancing 1826 * us as a gateway to somewhere. However, we must let the routing 1827 * protocol deal with that. 1828 * 1829 * The using_srcrt parameter indicates whether the packet is being forwarded 1830 * via a source route. 1831 */ 1832 void 1833 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop) 1834 { 1835 struct ip *ip = mtod(m, struct ip *); 1836 struct rtentry *rt; 1837 struct route fwd_ro; 1838 int error, type = 0, code = 0, destmtu = 0; 1839 struct mbuf *mcopy; 1840 n_long dest; 1841 struct in_addr pkt_dst; 1842 1843 dest = INADDR_ANY; 1844 /* 1845 * Cache the destination address of the packet; this may be 1846 * changed by use of 'ipfw fwd'. 1847 */ 1848 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 1849 1850 #ifdef DIAGNOSTIC 1851 if (ipprintfs) 1852 kprintf("forward: src %x dst %x ttl %x\n", 1853 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1854 #endif 1855 1856 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1857 ipstat.ips_cantforward++; 1858 m_freem(m); 1859 return; 1860 } 1861 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1862 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1863 return; 1864 } 1865 1866 bzero(&fwd_ro, sizeof(fwd_ro)); 1867 ip_rtaddr(pkt_dst, &fwd_ro); 1868 if (fwd_ro.ro_rt == NULL) { 1869 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1870 return; 1871 } 1872 rt = fwd_ro.ro_rt; 1873 1874 /* 1875 * Save the IP header and at most 8 bytes of the payload, 1876 * in case we need to generate an ICMP message to the src. 1877 * 1878 * XXX this can be optimized a lot by saving the data in a local 1879 * buffer on the stack (72 bytes at most), and only allocating the 1880 * mbuf if really necessary. The vast majority of the packets 1881 * are forwarded without having to send an ICMP back (either 1882 * because unnecessary, or because rate limited), so we are 1883 * really we are wasting a lot of work here. 1884 * 1885 * We don't use m_copy() because it might return a reference 1886 * to a shared cluster. Both this function and ip_output() 1887 * assume exclusive access to the IP header in `m', so any 1888 * data in a cluster may change before we reach icmp_error(). 1889 */ 1890 MGETHDR(mcopy, MB_DONTWAIT, m->m_type); 1891 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) { 1892 /* 1893 * It's probably ok if the pkthdr dup fails (because 1894 * the deep copy of the tag chain failed), but for now 1895 * be conservative and just discard the copy since 1896 * code below may some day want the tags. 1897 */ 1898 m_free(mcopy); 1899 mcopy = NULL; 1900 } 1901 if (mcopy != NULL) { 1902 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1903 (int)ip->ip_len); 1904 mcopy->m_pkthdr.len = mcopy->m_len; 1905 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1906 } 1907 1908 if (!ipstealth) 1909 ip->ip_ttl -= IPTTLDEC; 1910 1911 /* 1912 * If forwarding packet using same interface that it came in on, 1913 * perhaps should send a redirect to sender to shortcut a hop. 1914 * Only send redirect if source is sending directly to us, 1915 * and if packet was not source routed (or has any options). 1916 * Also, don't send redirect if forwarding using a default route 1917 * or a route modified by a redirect. 1918 */ 1919 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1920 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1921 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1922 ipsendredirects && !using_srcrt && next_hop == NULL) { 1923 u_long src = ntohl(ip->ip_src.s_addr); 1924 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa; 1925 1926 if (rt_ifa != NULL && 1927 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) { 1928 if (rt->rt_flags & RTF_GATEWAY) 1929 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1930 else 1931 dest = pkt_dst.s_addr; 1932 /* 1933 * Router requirements says to only send 1934 * host redirects. 1935 */ 1936 type = ICMP_REDIRECT; 1937 code = ICMP_REDIRECT_HOST; 1938 #ifdef DIAGNOSTIC 1939 if (ipprintfs) 1940 kprintf("redirect (%d) to %x\n", code, dest); 1941 #endif 1942 } 1943 } 1944 1945 error = ip_output(m, NULL, &fwd_ro, IP_FORWARDING, NULL, NULL); 1946 if (error == 0) { 1947 ipstat.ips_forward++; 1948 if (type == 0) { 1949 if (mcopy) { 1950 ipflow_create(&fwd_ro, mcopy); 1951 m_freem(mcopy); 1952 } 1953 goto done; 1954 } else { 1955 ipstat.ips_redirectsent++; 1956 } 1957 } else { 1958 ipstat.ips_cantforward++; 1959 } 1960 1961 if (mcopy == NULL) 1962 goto done; 1963 1964 /* 1965 * Send ICMP message. 1966 */ 1967 1968 switch (error) { 1969 1970 case 0: /* forwarded, but need redirect */ 1971 /* type, code set above */ 1972 break; 1973 1974 case ENETUNREACH: /* shouldn't happen, checked above */ 1975 case EHOSTUNREACH: 1976 case ENETDOWN: 1977 case EHOSTDOWN: 1978 default: 1979 type = ICMP_UNREACH; 1980 code = ICMP_UNREACH_HOST; 1981 break; 1982 1983 case EMSGSIZE: 1984 type = ICMP_UNREACH; 1985 code = ICMP_UNREACH_NEEDFRAG; 1986 #ifdef IPSEC 1987 /* 1988 * If the packet is routed over IPsec tunnel, tell the 1989 * originator the tunnel MTU. 1990 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1991 * XXX quickhack!!! 1992 */ 1993 if (fwd_ro.ro_rt != NULL) { 1994 struct secpolicy *sp = NULL; 1995 int ipsecerror; 1996 int ipsechdr; 1997 struct route *ro; 1998 1999 sp = ipsec4_getpolicybyaddr(mcopy, 2000 IPSEC_DIR_OUTBOUND, 2001 IP_FORWARDING, 2002 &ipsecerror); 2003 2004 if (sp == NULL) 2005 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2006 else { 2007 /* count IPsec header size */ 2008 ipsechdr = ipsec4_hdrsiz(mcopy, 2009 IPSEC_DIR_OUTBOUND, 2010 NULL); 2011 2012 /* 2013 * find the correct route for outer IPv4 2014 * header, compute tunnel MTU. 2015 * 2016 */ 2017 if (sp->req != NULL && sp->req->sav != NULL && 2018 sp->req->sav->sah != NULL) { 2019 ro = &sp->req->sav->sah->sa_route; 2020 if (ro->ro_rt != NULL && 2021 ro->ro_rt->rt_ifp != NULL) { 2022 destmtu = 2023 ro->ro_rt->rt_ifp->if_mtu; 2024 destmtu -= ipsechdr; 2025 } 2026 } 2027 2028 key_freesp(sp); 2029 } 2030 } 2031 #elif FAST_IPSEC 2032 /* 2033 * If the packet is routed over IPsec tunnel, tell the 2034 * originator the tunnel MTU. 2035 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2036 * XXX quickhack!!! 2037 */ 2038 if (fwd_ro.ro_rt != NULL) { 2039 struct secpolicy *sp = NULL; 2040 int ipsecerror; 2041 int ipsechdr; 2042 struct route *ro; 2043 2044 sp = ipsec_getpolicybyaddr(mcopy, 2045 IPSEC_DIR_OUTBOUND, 2046 IP_FORWARDING, 2047 &ipsecerror); 2048 2049 if (sp == NULL) 2050 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2051 else { 2052 /* count IPsec header size */ 2053 ipsechdr = ipsec4_hdrsiz(mcopy, 2054 IPSEC_DIR_OUTBOUND, 2055 NULL); 2056 2057 /* 2058 * find the correct route for outer IPv4 2059 * header, compute tunnel MTU. 2060 */ 2061 2062 if (sp->req != NULL && 2063 sp->req->sav != NULL && 2064 sp->req->sav->sah != NULL) { 2065 ro = &sp->req->sav->sah->sa_route; 2066 if (ro->ro_rt != NULL && 2067 ro->ro_rt->rt_ifp != NULL) { 2068 destmtu = 2069 ro->ro_rt->rt_ifp->if_mtu; 2070 destmtu -= ipsechdr; 2071 } 2072 } 2073 2074 KEY_FREESP(&sp); 2075 } 2076 } 2077 #else /* !IPSEC && !FAST_IPSEC */ 2078 if (fwd_ro.ro_rt != NULL) 2079 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2080 #endif /*IPSEC*/ 2081 ipstat.ips_cantfrag++; 2082 break; 2083 2084 case ENOBUFS: 2085 /* 2086 * A router should not generate ICMP_SOURCEQUENCH as 2087 * required in RFC1812 Requirements for IP Version 4 Routers. 2088 * Source quench could be a big problem under DoS attacks, 2089 * or if the underlying interface is rate-limited. 2090 * Those who need source quench packets may re-enable them 2091 * via the net.inet.ip.sendsourcequench sysctl. 2092 */ 2093 if (!ip_sendsourcequench) { 2094 m_freem(mcopy); 2095 goto done; 2096 } else { 2097 type = ICMP_SOURCEQUENCH; 2098 code = 0; 2099 } 2100 break; 2101 2102 case EACCES: /* ipfw denied packet */ 2103 m_freem(mcopy); 2104 goto done; 2105 } 2106 icmp_error(mcopy, type, code, dest, destmtu); 2107 done: 2108 if (fwd_ro.ro_rt != NULL) 2109 RTFREE(fwd_ro.ro_rt); 2110 } 2111 2112 void 2113 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2114 struct mbuf *m) 2115 { 2116 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2117 struct timeval tv; 2118 2119 microtime(&tv); 2120 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2121 SCM_TIMESTAMP, SOL_SOCKET); 2122 if (*mp) 2123 mp = &(*mp)->m_next; 2124 } 2125 if (inp->inp_flags & INP_RECVDSTADDR) { 2126 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2127 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2128 if (*mp) 2129 mp = &(*mp)->m_next; 2130 } 2131 if (inp->inp_flags & INP_RECVTTL) { 2132 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2133 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2134 if (*mp) 2135 mp = &(*mp)->m_next; 2136 } 2137 #ifdef notyet 2138 /* XXX 2139 * Moving these out of udp_input() made them even more broken 2140 * than they already were. 2141 */ 2142 /* options were tossed already */ 2143 if (inp->inp_flags & INP_RECVOPTS) { 2144 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2145 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2146 if (*mp) 2147 mp = &(*mp)->m_next; 2148 } 2149 /* ip_srcroute doesn't do what we want here, need to fix */ 2150 if (inp->inp_flags & INP_RECVRETOPTS) { 2151 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 2152 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2153 if (*mp) 2154 mp = &(*mp)->m_next; 2155 } 2156 #endif 2157 if (inp->inp_flags & INP_RECVIF) { 2158 struct ifnet *ifp; 2159 struct sdlbuf { 2160 struct sockaddr_dl sdl; 2161 u_char pad[32]; 2162 } sdlbuf; 2163 struct sockaddr_dl *sdp; 2164 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2165 2166 if (((ifp = m->m_pkthdr.rcvif)) && 2167 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2168 sdp = IF_LLSOCKADDR(ifp); 2169 /* 2170 * Change our mind and don't try copy. 2171 */ 2172 if ((sdp->sdl_family != AF_LINK) || 2173 (sdp->sdl_len > sizeof(sdlbuf))) { 2174 goto makedummy; 2175 } 2176 bcopy(sdp, sdl2, sdp->sdl_len); 2177 } else { 2178 makedummy: 2179 sdl2->sdl_len = 2180 offsetof(struct sockaddr_dl, sdl_data[0]); 2181 sdl2->sdl_family = AF_LINK; 2182 sdl2->sdl_index = 0; 2183 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2184 } 2185 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2186 IP_RECVIF, IPPROTO_IP); 2187 if (*mp) 2188 mp = &(*mp)->m_next; 2189 } 2190 } 2191 2192 /* 2193 * XXX these routines are called from the upper part of the kernel. 2194 * 2195 * They could also be moved to ip_mroute.c, since all the RSVP 2196 * handling is done there already. 2197 */ 2198 int 2199 ip_rsvp_init(struct socket *so) 2200 { 2201 if (so->so_type != SOCK_RAW || 2202 so->so_proto->pr_protocol != IPPROTO_RSVP) 2203 return EOPNOTSUPP; 2204 2205 if (ip_rsvpd != NULL) 2206 return EADDRINUSE; 2207 2208 ip_rsvpd = so; 2209 /* 2210 * This may seem silly, but we need to be sure we don't over-increment 2211 * the RSVP counter, in case something slips up. 2212 */ 2213 if (!ip_rsvp_on) { 2214 ip_rsvp_on = 1; 2215 rsvp_on++; 2216 } 2217 2218 return 0; 2219 } 2220 2221 int 2222 ip_rsvp_done(void) 2223 { 2224 ip_rsvpd = NULL; 2225 /* 2226 * This may seem silly, but we need to be sure we don't over-decrement 2227 * the RSVP counter, in case something slips up. 2228 */ 2229 if (ip_rsvp_on) { 2230 ip_rsvp_on = 0; 2231 rsvp_on--; 2232 } 2233 return 0; 2234 } 2235 2236 void 2237 rsvp_input(struct mbuf *m, ...) /* XXX must fixup manually */ 2238 { 2239 int off, proto; 2240 __va_list ap; 2241 2242 __va_start(ap, m); 2243 off = __va_arg(ap, int); 2244 proto = __va_arg(ap, int); 2245 __va_end(ap); 2246 2247 if (rsvp_input_p) { /* call the real one if loaded */ 2248 rsvp_input_p(m, off, proto); 2249 return; 2250 } 2251 2252 /* Can still get packets with rsvp_on = 0 if there is a local member 2253 * of the group to which the RSVP packet is addressed. But in this 2254 * case we want to throw the packet away. 2255 */ 2256 2257 if (!rsvp_on) { 2258 m_freem(m); 2259 return; 2260 } 2261 2262 if (ip_rsvpd != NULL) { 2263 rip_input(m, off, proto); 2264 return; 2265 } 2266 /* Drop the packet */ 2267 m_freem(m); 2268 } 2269