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 ip_mpsafe = 1; 144 TUNABLE_INT("net.inet.ip.mpsafe", &ip_mpsafe); 145 146 int ipforwarding = 0; 147 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 148 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 149 150 static int ipsendredirects = 1; /* XXX */ 151 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 152 &ipsendredirects, 0, "Enable sending IP redirects"); 153 154 int ip_defttl = IPDEFTTL; 155 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 156 &ip_defttl, 0, "Maximum TTL on IP packets"); 157 158 static int ip_dosourceroute = 0; 159 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 160 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 161 162 static int ip_acceptsourceroute = 0; 163 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 164 CTLFLAG_RW, &ip_acceptsourceroute, 0, 165 "Enable accepting source routed IP packets"); 166 167 static int ip_keepfaith = 0; 168 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 169 &ip_keepfaith, 0, 170 "Enable packet capture for FAITH IPv4->IPv6 translator daemon"); 171 172 static int nipq = 0; /* total # of reass queues */ 173 static int maxnipq; 174 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 175 &maxnipq, 0, 176 "Maximum number of IPv4 fragment reassembly queue entries"); 177 178 static int maxfragsperpacket; 179 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 180 &maxfragsperpacket, 0, 181 "Maximum number of IPv4 fragments allowed per packet"); 182 183 static int ip_sendsourcequench = 0; 184 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 185 &ip_sendsourcequench, 0, 186 "Enable the transmission of source quench packets"); 187 188 int ip_do_randomid = 1; 189 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 190 &ip_do_randomid, 0, 191 "Assign random ip_id values"); 192 /* 193 * XXX - Setting ip_checkinterface mostly implements the receive side of 194 * the Strong ES model described in RFC 1122, but since the routing table 195 * and transmit implementation do not implement the Strong ES model, 196 * setting this to 1 results in an odd hybrid. 197 * 198 * XXX - ip_checkinterface currently must be disabled if you use ipnat 199 * to translate the destination address to another local interface. 200 * 201 * XXX - ip_checkinterface must be disabled if you add IP aliases 202 * to the loopback interface instead of the interface where the 203 * packets for those addresses are received. 204 */ 205 static int ip_checkinterface = 0; 206 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 207 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 208 209 static struct lwkt_token ipq_token = LWKT_TOKEN_MP_INITIALIZER(ipq_token); 210 211 #ifdef DIAGNOSTIC 212 static int ipprintfs = 0; 213 #endif 214 215 extern int udp_mpsafe_proto; 216 extern int tcp_mpsafe_proto; 217 218 extern struct domain inetdomain; 219 extern struct protosw inetsw[]; 220 u_char ip_protox[IPPROTO_MAX]; 221 struct in_ifaddrhead in_ifaddrheads[MAXCPU]; /* first inet address */ 222 struct in_ifaddrhashhead *in_ifaddrhashtbls[MAXCPU]; 223 /* inet addr hash table */ 224 u_long in_ifaddrhmask; /* mask for hash table */ 225 226 struct ip_stats ipstats_percpu[MAXCPU]; 227 #ifdef SMP 228 static int 229 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 230 { 231 int cpu, error = 0; 232 233 for (cpu = 0; cpu < ncpus; ++cpu) { 234 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu], 235 sizeof(struct ip_stats)))) 236 break; 237 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu], 238 sizeof(struct ip_stats)))) 239 break; 240 } 241 242 return (error); 243 } 244 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 245 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 246 #else 247 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 248 &ipstat, ip_stats, "IP statistics"); 249 #endif 250 251 /* Packet reassembly stuff */ 252 #define IPREASS_NHASH_LOG2 6 253 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 254 #define IPREASS_HMASK (IPREASS_NHASH - 1) 255 #define IPREASS_HASH(x,y) \ 256 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 257 258 static struct ipq ipq[IPREASS_NHASH]; 259 260 #ifdef IPCTL_DEFMTU 261 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 262 &ip_mtu, 0, "Default MTU"); 263 #endif 264 265 #ifdef IPSTEALTH 266 static int ipstealth = 0; 267 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, ""); 268 #else 269 static const int ipstealth = 0; 270 #endif 271 272 struct mbuf *(*ip_divert_p)(struct mbuf *, int, int); 273 274 struct pfil_head inet_pfil_hook; 275 276 /* 277 * struct ip_srcrt_opt is used to store packet state while it travels 278 * through the stack. 279 * 280 * XXX Note that the code even makes assumptions on the size and 281 * alignment of fields inside struct ip_srcrt so e.g. adding some 282 * fields will break the code. This needs to be fixed. 283 * 284 * We need to save the IP options in case a protocol wants to respond 285 * to an incoming packet over the same route if the packet got here 286 * using IP source routing. This allows connection establishment and 287 * maintenance when the remote end is on a network that is not known 288 * to us. 289 */ 290 struct ip_srcrt { 291 struct in_addr dst; /* final destination */ 292 char nop; /* one NOP to align */ 293 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 294 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 295 }; 296 297 struct ip_srcrt_opt { 298 int ip_nhops; 299 struct ip_srcrt ip_srcrt; 300 }; 301 302 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 303 static struct malloc_pipe ipq_mpipe; 304 305 static void save_rte(struct mbuf *, u_char *, struct in_addr); 306 static int ip_dooptions(struct mbuf *m, int, struct sockaddr_in *); 307 static void ip_freef(struct ipq *); 308 static void ip_input_handler(struct netmsg *); 309 310 /* 311 * IP initialization: fill in IP protocol switch table. 312 * All protocols not implemented in kernel go to raw IP protocol handler. 313 */ 314 void 315 ip_init(void) 316 { 317 struct protosw *pr; 318 uint32_t flags; 319 int i; 320 #ifdef SMP 321 int cpu; 322 #endif 323 324 /* 325 * Make sure we can handle a reasonable number of fragments but 326 * cap it at 4000 (XXX). 327 */ 328 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 329 IFQ_MAXLEN, 4000, 0, NULL); 330 for (i = 0; i < ncpus; ++i) { 331 TAILQ_INIT(&in_ifaddrheads[i]); 332 in_ifaddrhashtbls[i] = 333 hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 334 } 335 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 336 if (pr == NULL) 337 panic("ip_init"); 338 for (i = 0; i < IPPROTO_MAX; i++) 339 ip_protox[i] = pr - inetsw; 340 for (pr = inetdomain.dom_protosw; 341 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 342 if (pr->pr_domain->dom_family == PF_INET && pr->pr_protocol) { 343 if (pr->pr_protocol != IPPROTO_RAW) 344 ip_protox[pr->pr_protocol] = pr - inetsw; 345 346 /* XXX */ 347 switch (pr->pr_protocol) { 348 case IPPROTO_TCP: 349 if (tcp_mpsafe_proto) 350 pr->pr_flags |= PR_MPSAFE; 351 break; 352 353 case IPPROTO_UDP: 354 if (udp_mpsafe_proto) 355 pr->pr_flags |= PR_MPSAFE; 356 break; 357 } 358 } 359 } 360 361 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 362 inet_pfil_hook.ph_af = AF_INET; 363 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) { 364 kprintf("%s: WARNING: unable to register pfil hook, " 365 "error %d\n", __func__, i); 366 } 367 368 for (i = 0; i < IPREASS_NHASH; i++) 369 ipq[i].next = ipq[i].prev = &ipq[i]; 370 371 maxnipq = nmbclusters / 32; 372 maxfragsperpacket = 16; 373 374 ip_id = time_second & 0xffff; 375 376 /* 377 * Initialize IP statistics counters for each CPU. 378 * 379 */ 380 #ifdef SMP 381 for (cpu = 0; cpu < ncpus; ++cpu) { 382 bzero(&ipstats_percpu[cpu], sizeof(struct ip_stats)); 383 } 384 #else 385 bzero(&ipstat, sizeof(struct ip_stats)); 386 #endif 387 388 #if defined(IPSEC) || defined(FAST_IPSEC) 389 /* XXX IPSEC is not MPSAFE yet */ 390 flags = NETISR_FLAG_NOTMPSAFE; 391 #else 392 if (ip_mpsafe) { 393 kprintf("ip: MPSAFE\n"); 394 flags = NETISR_FLAG_MPSAFE; 395 } else { 396 flags = NETISR_FLAG_NOTMPSAFE; 397 } 398 #endif 399 netisr_register(NETISR_IP, ip_mport_in, ip_mport_pktinfo, 400 ip_input_handler, flags); 401 } 402 403 /* Do transport protocol processing. */ 404 static void 405 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip) 406 { 407 const struct protosw *pr = &inetsw[ip_protox[ip->ip_p]]; 408 409 /* 410 * Switch out to protocol's input routine. 411 */ 412 PR_GET_MPLOCK(pr); 413 pr->pr_input(m, hlen, ip->ip_p); 414 PR_REL_MPLOCK(pr); 415 } 416 417 static void 418 transport_processing_handler(netmsg_t netmsg) 419 { 420 struct netmsg_packet *pmsg = (struct netmsg_packet *)netmsg; 421 struct ip *ip; 422 int hlen; 423 424 ip = mtod(pmsg->nm_packet, struct ip *); 425 hlen = pmsg->nm_netmsg.nm_lmsg.u.ms_result; 426 427 transport_processing_oncpu(pmsg->nm_packet, hlen, ip); 428 /* netmsg was embedded in the mbuf, do not reply! */ 429 } 430 431 static void 432 ip_input_handler(struct netmsg *msg0) 433 { 434 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet; 435 436 ip_input(m); 437 /* msg0 was embedded in the mbuf, do not reply! */ 438 } 439 440 /* 441 * IP input routine. Checksum and byte swap header. If fragmented 442 * try to reassemble. Process options. Pass to next level. 443 */ 444 void 445 ip_input(struct mbuf *m) 446 { 447 struct ip *ip; 448 struct in_ifaddr *ia = NULL; 449 struct in_ifaddr_container *iac; 450 int hlen, checkif; 451 u_short sum; 452 struct in_addr pkt_dst; 453 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 454 struct in_addr odst; /* original dst address(NAT) */ 455 struct m_tag *mtag; 456 struct sockaddr_in *next_hop = NULL; 457 lwkt_port_t port; 458 #ifdef FAST_IPSEC 459 struct tdb_ident *tdbi; 460 struct secpolicy *sp; 461 int error; 462 #endif 463 464 M_ASSERTPKTHDR(m); 465 466 /* 467 * This does necessary pullups and figures out the protocol 468 * port. If the packet is really badly formed it will blow 469 * it away and return NULL. 470 * 471 * We do not necessarily make use of the port (forwarding, 472 * defragmentation, etc). 473 */ 474 port = ip_mport(&m, IP_MPORT_IN); 475 if (port == NULL) 476 return; 477 ip = mtod(m, struct ip *); 478 479 /* 480 * Pull out certain tags 481 */ 482 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 483 /* Next hop */ 484 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 485 KKASSERT(mtag != NULL); 486 next_hop = m_tag_data(mtag); 487 } 488 489 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 490 /* dummynet already filtered us */ 491 ip = mtod(m, struct ip *); 492 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 493 goto iphack; 494 } 495 496 ipstat.ips_total++; 497 498 /* length checks already done in ip_mport() */ 499 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); 500 501 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 502 ipstat.ips_badvers++; 503 goto bad; 504 } 505 506 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 507 /* length checks already done in ip_mport() */ 508 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 509 KASSERT(m->m_len >= hlen, ("complete IP header not in one mbuf")); 510 511 /* 127/8 must not appear on wire - RFC1122 */ 512 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 513 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 514 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 515 ipstat.ips_badaddr++; 516 goto bad; 517 } 518 } 519 520 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 521 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 522 } else { 523 if (hlen == sizeof(struct ip)) 524 sum = in_cksum_hdr(ip); 525 else 526 sum = in_cksum(m, hlen); 527 } 528 if (sum != 0) { 529 ipstat.ips_badsum++; 530 goto bad; 531 } 532 533 #ifdef ALTQ 534 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 535 /* packet is dropped by traffic conditioner */ 536 return; 537 } 538 #endif 539 /* 540 * Convert fields to host representation. 541 */ 542 ip->ip_len = ntohs(ip->ip_len); 543 ip->ip_off = ntohs(ip->ip_off); 544 545 /* length checks already done in ip_mport() */ 546 KASSERT(ip->ip_len >= hlen, ("total length less then header length")); 547 KASSERT(m->m_pkthdr.len >= ip->ip_len, ("mbuf too short")); 548 549 /* 550 * Trim mbufs if longer than the IP header would have us expect. 551 */ 552 if (m->m_pkthdr.len > ip->ip_len) { 553 if (m->m_len == m->m_pkthdr.len) { 554 m->m_len = ip->ip_len; 555 m->m_pkthdr.len = ip->ip_len; 556 } else { 557 m_adj(m, ip->ip_len - m->m_pkthdr.len); 558 } 559 } 560 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 561 /* 562 * Bypass packet filtering for packets from a tunnel (gif). 563 */ 564 if (ipsec_gethist(m, NULL)) 565 goto pass; 566 #endif 567 568 /* 569 * IpHack's section. 570 * Right now when no processing on packet has done 571 * and it is still fresh out of network we do our black 572 * deals with it. 573 * - Firewall: deny/allow/divert 574 * - Xlate: translate packet's addr/port (NAT). 575 * - Pipe: pass pkt through dummynet. 576 * - Wrap: fake packet's addr/port <unimpl.> 577 * - Encapsulate: put it in another IP and send out. <unimp.> 578 */ 579 580 iphack: 581 /* 582 * If we've been forwarded from the output side, then 583 * skip the firewall a second time 584 */ 585 if (next_hop != NULL) 586 goto ours; 587 588 /* No pfil hooks */ 589 if (!pfil_has_hooks(&inet_pfil_hook)) { 590 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 591 /* 592 * Strip dummynet tags from stranded packets 593 */ 594 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL); 595 KKASSERT(mtag != NULL); 596 m_tag_delete(m, mtag); 597 m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED; 598 } 599 goto pass; 600 } 601 602 /* 603 * Run through list of hooks for input packets. 604 * 605 * NB: Beware of the destination address changing (e.g. 606 * by NAT rewriting). When this happens, tell 607 * ip_forward to do the right thing. 608 */ 609 odst = ip->ip_dst; 610 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN)) 611 return; 612 if (m == NULL) /* consumed by filter */ 613 return; 614 ip = mtod(m, struct ip *); 615 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 616 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 617 618 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 619 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 620 KKASSERT(mtag != NULL); 621 next_hop = m_tag_data(mtag); 622 } 623 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 624 ip_dn_queue(m); 625 return; 626 } 627 if (m->m_pkthdr.fw_flags & FW_MBUF_REDISPATCH) { 628 m->m_pkthdr.fw_flags &= ~FW_MBUF_REDISPATCH; 629 } 630 pass: 631 /* 632 * Process options and, if not destined for us, 633 * ship it on. ip_dooptions returns 1 when an 634 * error was detected (causing an icmp message 635 * to be sent and the original packet to be freed). 636 */ 637 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, next_hop)) 638 return; 639 640 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 641 * matter if it is destined to another node, or whether it is 642 * a multicast one, RSVP wants it! and prevents it from being forwarded 643 * anywhere else. Also checks if the rsvp daemon is running before 644 * grabbing the packet. 645 */ 646 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 647 goto ours; 648 649 /* 650 * Check our list of addresses, to see if the packet is for us. 651 * If we don't have any addresses, assume any unicast packet 652 * we receive might be for us (and let the upper layers deal 653 * with it). 654 */ 655 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) && 656 !(m->m_flags & (M_MCAST | M_BCAST))) 657 goto ours; 658 659 /* 660 * Cache the destination address of the packet; this may be 661 * changed by use of 'ipfw fwd'. 662 */ 663 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 664 665 /* 666 * Enable a consistency check between the destination address 667 * and the arrival interface for a unicast packet (the RFC 1122 668 * strong ES model) if IP forwarding is disabled and the packet 669 * is not locally generated and the packet is not subject to 670 * 'ipfw fwd'. 671 * 672 * XXX - Checking also should be disabled if the destination 673 * address is ipnat'ed to a different interface. 674 * 675 * XXX - Checking is incompatible with IP aliases added 676 * to the loopback interface instead of the interface where 677 * the packets are received. 678 */ 679 checkif = ip_checkinterface && 680 !ipforwarding && 681 m->m_pkthdr.rcvif != NULL && 682 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 683 next_hop == NULL; 684 685 /* 686 * Check for exact addresses in the hash bucket. 687 */ 688 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 689 ia = iac->ia; 690 691 /* 692 * If the address matches, verify that the packet 693 * arrived via the correct interface if checking is 694 * enabled. 695 */ 696 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 697 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 698 goto ours; 699 } 700 ia = NULL; 701 702 /* 703 * Check for broadcast addresses. 704 * 705 * Only accept broadcast packets that arrive via the matching 706 * interface. Reception of forwarded directed broadcasts would 707 * be handled via ip_forward() and ether_output() with the loopback 708 * into the stack for SIMPLEX interfaces handled by ether_output(). 709 */ 710 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 711 struct ifaddr_container *ifac; 712 713 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 714 ifa_link) { 715 struct ifaddr *ifa = ifac->ifa; 716 717 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 718 continue; 719 if (ifa->ifa_addr->sa_family != AF_INET) 720 continue; 721 ia = ifatoia(ifa); 722 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 723 pkt_dst.s_addr) 724 goto ours; 725 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 726 goto ours; 727 #ifdef BOOTP_COMPAT 728 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 729 goto ours; 730 #endif 731 } 732 } 733 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 734 struct in_multi *inm; 735 736 /* XXX Multicast is not MPSAFE yet */ 737 get_mplock(); 738 739 if (ip_mrouter != NULL) { 740 /* 741 * If we are acting as a multicast router, all 742 * incoming multicast packets are passed to the 743 * kernel-level multicast forwarding function. 744 * The packet is returned (relatively) intact; if 745 * ip_mforward() returns a non-zero value, the packet 746 * must be discarded, else it may be accepted below. 747 */ 748 if (ip_mforward != NULL && 749 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 750 rel_mplock(); 751 ipstat.ips_cantforward++; 752 m_freem(m); 753 return; 754 } 755 756 /* 757 * The process-level routing daemon needs to receive 758 * all multicast IGMP packets, whether or not this 759 * host belongs to their destination groups. 760 */ 761 if (ip->ip_p == IPPROTO_IGMP) { 762 rel_mplock(); 763 goto ours; 764 } 765 ipstat.ips_forward++; 766 } 767 /* 768 * See if we belong to the destination multicast group on the 769 * arrival interface. 770 */ 771 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 772 if (inm == NULL) { 773 rel_mplock(); 774 ipstat.ips_notmember++; 775 m_freem(m); 776 return; 777 } 778 779 rel_mplock(); 780 goto ours; 781 } 782 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 783 goto ours; 784 if (ip->ip_dst.s_addr == INADDR_ANY) 785 goto ours; 786 787 /* 788 * FAITH(Firewall Aided Internet Translator) 789 */ 790 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 791 if (ip_keepfaith) { 792 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 793 goto ours; 794 } 795 m_freem(m); 796 return; 797 } 798 799 /* 800 * Not for us; forward if possible and desirable. 801 */ 802 if (!ipforwarding) { 803 ipstat.ips_cantforward++; 804 m_freem(m); 805 } else { 806 #ifdef IPSEC 807 /* 808 * Enforce inbound IPsec SPD. 809 */ 810 if (ipsec4_in_reject(m, NULL)) { 811 ipsecstat.in_polvio++; 812 goto bad; 813 } 814 #endif 815 #ifdef FAST_IPSEC 816 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 817 crit_enter(); 818 if (mtag != NULL) { 819 tdbi = (struct tdb_ident *)m_tag_data(mtag); 820 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 821 } else { 822 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 823 IP_FORWARDING, &error); 824 } 825 if (sp == NULL) { /* NB: can happen if error */ 826 crit_exit(); 827 /*XXX error stat???*/ 828 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 829 goto bad; 830 } 831 832 /* 833 * Check security policy against packet attributes. 834 */ 835 error = ipsec_in_reject(sp, m); 836 KEY_FREESP(&sp); 837 crit_exit(); 838 if (error) { 839 ipstat.ips_cantforward++; 840 goto bad; 841 } 842 #endif 843 ip_forward(m, using_srcrt, next_hop); 844 } 845 return; 846 847 ours: 848 849 /* 850 * IPSTEALTH: Process non-routing options only 851 * if the packet is destined for us. 852 */ 853 if (ipstealth && 854 hlen > sizeof(struct ip) && 855 ip_dooptions(m, 1, next_hop)) 856 return; 857 858 /* Count the packet in the ip address stats */ 859 if (ia != NULL) { 860 ia->ia_ifa.if_ipackets++; 861 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 862 } 863 864 /* 865 * If offset or IP_MF are set, must reassemble. 866 * Otherwise, nothing need be done. 867 * (We could look in the reassembly queue to see 868 * if the packet was previously fragmented, 869 * but it's not worth the time; just let them time out.) 870 */ 871 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 872 /* 873 * Attempt reassembly; if it succeeds, proceed. 874 * ip_reass() will return a different mbuf. 875 */ 876 m = ip_reass(m); 877 if (m == NULL) 878 return; 879 ip = mtod(m, struct ip *); 880 881 /* Get the header length of the reassembled packet */ 882 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 883 } else { 884 ip->ip_len -= hlen; 885 } 886 887 #ifdef IPSEC 888 /* 889 * enforce IPsec policy checking if we are seeing last header. 890 * note that we do not visit this with protocols with pcb layer 891 * code - like udp/tcp/raw ip. 892 */ 893 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 894 ipsec4_in_reject(m, NULL)) { 895 ipsecstat.in_polvio++; 896 goto bad; 897 } 898 #endif 899 #if FAST_IPSEC 900 /* 901 * enforce IPsec policy checking if we are seeing last header. 902 * note that we do not visit this with protocols with pcb layer 903 * code - like udp/tcp/raw ip. 904 */ 905 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 906 /* 907 * Check if the packet has already had IPsec processing 908 * done. If so, then just pass it along. This tag gets 909 * set during AH, ESP, etc. input handling, before the 910 * packet is returned to the ip input queue for delivery. 911 */ 912 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 913 crit_enter(); 914 if (mtag != NULL) { 915 tdbi = (struct tdb_ident *)m_tag_data(mtag); 916 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 917 } else { 918 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 919 IP_FORWARDING, &error); 920 } 921 if (sp != NULL) { 922 /* 923 * Check security policy against packet attributes. 924 */ 925 error = ipsec_in_reject(sp, m); 926 KEY_FREESP(&sp); 927 } else { 928 /* XXX error stat??? */ 929 error = EINVAL; 930 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 931 goto bad; 932 } 933 crit_exit(); 934 if (error) 935 goto bad; 936 } 937 #endif /* FAST_IPSEC */ 938 939 /* 940 * NOTE: ip_len is now in host form and adjusted down by hlen for 941 * protocol processing. 942 * 943 * We must forward the packet to the correct protocol thread if 944 * we are not already in it. 945 */ 946 ipstat.ips_delivered++; 947 948 if (port != &curthread->td_msgport) { 949 struct netmsg_packet *pmsg; 950 951 pmsg = &m->m_hdr.mh_netmsg; 952 netmsg_init(&pmsg->nm_netmsg, NULL, &netisr_apanic_rport, 953 MSGF_MPSAFE, transport_processing_handler); 954 pmsg->nm_packet = m; 955 pmsg->nm_netmsg.nm_lmsg.u.ms_result = hlen; 956 957 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg); 958 } else { 959 transport_processing_oncpu(m, hlen, ip); 960 } 961 return; 962 963 bad: 964 m_freem(m); 965 } 966 967 /* 968 * Take incoming datagram fragment and try to reassemble it into 969 * whole datagram. If a chain for reassembly of this datagram already 970 * exists, then it is given as fp; otherwise have to make a chain. 971 */ 972 struct mbuf * 973 ip_reass(struct mbuf *m) 974 { 975 struct ip *ip = mtod(m, struct ip *); 976 struct mbuf *p = NULL, *q, *nq; 977 struct mbuf *n; 978 struct ipq *fp = NULL; 979 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 980 int i, next; 981 u_short sum; 982 983 /* If maxnipq is 0, never accept fragments. */ 984 if (maxnipq == 0) { 985 ipstat.ips_fragments++; 986 ipstat.ips_fragdropped++; 987 m_freem(m); 988 return NULL; 989 } 990 991 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 992 /* 993 * Look for queue of fragments of this datagram. 994 */ 995 lwkt_gettoken(&ipq_token); 996 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) { 997 if (ip->ip_id == fp->ipq_id && 998 ip->ip_src.s_addr == fp->ipq_src.s_addr && 999 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 1000 ip->ip_p == fp->ipq_p) 1001 goto found; 1002 } 1003 1004 fp = NULL; 1005 1006 /* 1007 * Enforce upper bound on number of fragmented packets 1008 * for which we attempt reassembly; 1009 * If maxnipq is -1, accept all fragments without limitation. 1010 */ 1011 if (nipq > maxnipq && maxnipq > 0) { 1012 /* 1013 * drop something from the tail of the current queue 1014 * before proceeding further 1015 */ 1016 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 1017 for (i = 0; i < IPREASS_NHASH; i++) { 1018 if (ipq[i].prev != &ipq[i]) { 1019 ipstat.ips_fragtimeout += 1020 ipq[i].prev->ipq_nfrags; 1021 ip_freef(ipq[i].prev); 1022 break; 1023 } 1024 } 1025 } else { 1026 ipstat.ips_fragtimeout += 1027 ipq[sum].prev->ipq_nfrags; 1028 ip_freef(ipq[sum].prev); 1029 } 1030 } 1031 found: 1032 /* 1033 * Adjust ip_len to not reflect header, 1034 * convert offset of this to bytes. 1035 */ 1036 ip->ip_len -= hlen; 1037 if (ip->ip_off & IP_MF) { 1038 /* 1039 * Make sure that fragments have a data length 1040 * that's a non-zero multiple of 8 bytes. 1041 */ 1042 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 1043 ipstat.ips_toosmall++; /* XXX */ 1044 m_freem(m); 1045 goto done; 1046 } 1047 m->m_flags |= M_FRAG; 1048 } else { 1049 m->m_flags &= ~M_FRAG; 1050 } 1051 ip->ip_off <<= 3; 1052 1053 ipstat.ips_fragments++; 1054 m->m_pkthdr.header = ip; 1055 1056 /* 1057 * If the hardware has not done csum over this fragment 1058 * then csum_data is not valid at all. 1059 */ 1060 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) 1061 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) { 1062 m->m_pkthdr.csum_data = 0; 1063 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR); 1064 } 1065 1066 /* 1067 * Presence of header sizes in mbufs 1068 * would confuse code below. 1069 */ 1070 m->m_data += hlen; 1071 m->m_len -= hlen; 1072 1073 /* 1074 * If first fragment to arrive, create a reassembly queue. 1075 */ 1076 if (fp == NULL) { 1077 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1078 goto dropfrag; 1079 insque(fp, &ipq[sum]); 1080 nipq++; 1081 fp->ipq_nfrags = 1; 1082 fp->ipq_ttl = IPFRAGTTL; 1083 fp->ipq_p = ip->ip_p; 1084 fp->ipq_id = ip->ip_id; 1085 fp->ipq_src = ip->ip_src; 1086 fp->ipq_dst = ip->ip_dst; 1087 fp->ipq_frags = m; 1088 m->m_nextpkt = NULL; 1089 goto inserted; 1090 } else { 1091 fp->ipq_nfrags++; 1092 } 1093 1094 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1095 1096 /* 1097 * Find a segment which begins after this one does. 1098 */ 1099 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1100 if (GETIP(q)->ip_off > ip->ip_off) 1101 break; 1102 } 1103 1104 /* 1105 * If there is a preceding segment, it may provide some of 1106 * our data already. If so, drop the data from the incoming 1107 * segment. If it provides all of our data, drop us, otherwise 1108 * stick new segment in the proper place. 1109 * 1110 * If some of the data is dropped from the the preceding 1111 * segment, then it's checksum is invalidated. 1112 */ 1113 if (p) { 1114 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1115 if (i > 0) { 1116 if (i >= ip->ip_len) 1117 goto dropfrag; 1118 m_adj(m, i); 1119 m->m_pkthdr.csum_flags = 0; 1120 ip->ip_off += i; 1121 ip->ip_len -= i; 1122 } 1123 m->m_nextpkt = p->m_nextpkt; 1124 p->m_nextpkt = m; 1125 } else { 1126 m->m_nextpkt = fp->ipq_frags; 1127 fp->ipq_frags = m; 1128 } 1129 1130 /* 1131 * While we overlap succeeding segments trim them or, 1132 * if they are completely covered, dequeue them. 1133 */ 1134 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1135 q = nq) { 1136 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1137 if (i < GETIP(q)->ip_len) { 1138 GETIP(q)->ip_len -= i; 1139 GETIP(q)->ip_off += i; 1140 m_adj(q, i); 1141 q->m_pkthdr.csum_flags = 0; 1142 break; 1143 } 1144 nq = q->m_nextpkt; 1145 m->m_nextpkt = nq; 1146 ipstat.ips_fragdropped++; 1147 fp->ipq_nfrags--; 1148 q->m_nextpkt = NULL; 1149 m_freem(q); 1150 } 1151 1152 inserted: 1153 /* 1154 * Check for complete reassembly and perform frag per packet 1155 * limiting. 1156 * 1157 * Frag limiting is performed here so that the nth frag has 1158 * a chance to complete the packet before we drop the packet. 1159 * As a result, n+1 frags are actually allowed per packet, but 1160 * only n will ever be stored. (n = maxfragsperpacket.) 1161 * 1162 */ 1163 next = 0; 1164 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1165 if (GETIP(q)->ip_off != next) { 1166 if (fp->ipq_nfrags > maxfragsperpacket) { 1167 ipstat.ips_fragdropped += fp->ipq_nfrags; 1168 ip_freef(fp); 1169 } 1170 goto done; 1171 } 1172 next += GETIP(q)->ip_len; 1173 } 1174 /* Make sure the last packet didn't have the IP_MF flag */ 1175 if (p->m_flags & M_FRAG) { 1176 if (fp->ipq_nfrags > maxfragsperpacket) { 1177 ipstat.ips_fragdropped += fp->ipq_nfrags; 1178 ip_freef(fp); 1179 } 1180 goto done; 1181 } 1182 1183 /* 1184 * Reassembly is complete. Make sure the packet is a sane size. 1185 */ 1186 q = fp->ipq_frags; 1187 ip = GETIP(q); 1188 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1189 ipstat.ips_toolong++; 1190 ipstat.ips_fragdropped += fp->ipq_nfrags; 1191 ip_freef(fp); 1192 goto done; 1193 } 1194 1195 /* 1196 * Concatenate fragments. 1197 */ 1198 m = q; 1199 n = m->m_next; 1200 m->m_next = NULL; 1201 m_cat(m, n); 1202 nq = q->m_nextpkt; 1203 q->m_nextpkt = NULL; 1204 for (q = nq; q != NULL; q = nq) { 1205 nq = q->m_nextpkt; 1206 q->m_nextpkt = NULL; 1207 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1208 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1209 m_cat(m, q); 1210 } 1211 1212 /* 1213 * Clean up the 1's complement checksum. Carry over 16 bits must 1214 * be added back. This assumes no more then 65535 packet fragments 1215 * were reassembled. A second carry can also occur (but not a third). 1216 */ 1217 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + 1218 (m->m_pkthdr.csum_data >> 16); 1219 if (m->m_pkthdr.csum_data > 0xFFFF) 1220 m->m_pkthdr.csum_data -= 0xFFFF; 1221 1222 /* 1223 * Create header for new ip packet by 1224 * modifying header of first packet; 1225 * dequeue and discard fragment reassembly header. 1226 * Make header visible. 1227 */ 1228 ip->ip_len = next; 1229 ip->ip_src = fp->ipq_src; 1230 ip->ip_dst = fp->ipq_dst; 1231 remque(fp); 1232 nipq--; 1233 mpipe_free(&ipq_mpipe, fp); 1234 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1235 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1236 /* some debugging cruft by sklower, below, will go away soon */ 1237 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1238 int plen = 0; 1239 1240 for (n = m; n; n = n->m_next) 1241 plen += n->m_len; 1242 m->m_pkthdr.len = plen; 1243 } 1244 1245 ipstat.ips_reassembled++; 1246 lwkt_reltoken(&ipq_token); 1247 return (m); 1248 1249 dropfrag: 1250 ipstat.ips_fragdropped++; 1251 if (fp != NULL) 1252 fp->ipq_nfrags--; 1253 m_freem(m); 1254 done: 1255 lwkt_reltoken(&ipq_token); 1256 return (NULL); 1257 1258 #undef GETIP 1259 } 1260 1261 /* 1262 * Free a fragment reassembly header and all 1263 * associated datagrams. 1264 * 1265 * Called with ipq_token held. 1266 */ 1267 static void 1268 ip_freef(struct ipq *fp) 1269 { 1270 struct mbuf *q; 1271 1272 /* 1273 * Remove first to protect against blocking 1274 */ 1275 remque(fp); 1276 1277 /* 1278 * Clean out at our leisure 1279 */ 1280 while (fp->ipq_frags) { 1281 q = fp->ipq_frags; 1282 fp->ipq_frags = q->m_nextpkt; 1283 q->m_nextpkt = NULL; 1284 m_freem(q); 1285 } 1286 mpipe_free(&ipq_mpipe, fp); 1287 nipq--; 1288 } 1289 1290 /* 1291 * IP timer processing; 1292 * if a timer expires on a reassembly 1293 * queue, discard it. 1294 */ 1295 void 1296 ip_slowtimo(void) 1297 { 1298 struct ipq *fp; 1299 int i; 1300 1301 lwkt_gettoken(&ipq_token); 1302 for (i = 0; i < IPREASS_NHASH; i++) { 1303 fp = ipq[i].next; 1304 if (fp == NULL) 1305 continue; 1306 while (fp != &ipq[i]) { 1307 --fp->ipq_ttl; 1308 fp = fp->next; 1309 if (fp->prev->ipq_ttl == 0) { 1310 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1311 ip_freef(fp->prev); 1312 } 1313 } 1314 } 1315 /* 1316 * If we are over the maximum number of fragments 1317 * (due to the limit being lowered), drain off 1318 * enough to get down to the new limit. 1319 */ 1320 if (maxnipq >= 0 && nipq > maxnipq) { 1321 for (i = 0; i < IPREASS_NHASH; i++) { 1322 while (nipq > maxnipq && 1323 (ipq[i].next != &ipq[i])) { 1324 ipstat.ips_fragdropped += 1325 ipq[i].next->ipq_nfrags; 1326 ip_freef(ipq[i].next); 1327 } 1328 } 1329 } 1330 lwkt_reltoken(&ipq_token); 1331 ipflow_slowtimo(); 1332 } 1333 1334 /* 1335 * Drain off all datagram fragments. 1336 */ 1337 void 1338 ip_drain(void) 1339 { 1340 int i; 1341 1342 lwkt_gettoken(&ipq_token); 1343 for (i = 0; i < IPREASS_NHASH; i++) { 1344 while (ipq[i].next != &ipq[i]) { 1345 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1346 ip_freef(ipq[i].next); 1347 } 1348 } 1349 lwkt_reltoken(&ipq_token); 1350 in_rtqdrain(); 1351 } 1352 1353 /* 1354 * Do option processing on a datagram, 1355 * possibly discarding it if bad options are encountered, 1356 * or forwarding it if source-routed. 1357 * The pass argument is used when operating in the IPSTEALTH 1358 * mode to tell what options to process: 1359 * [LS]SRR (pass 0) or the others (pass 1). 1360 * The reason for as many as two passes is that when doing IPSTEALTH, 1361 * non-routing options should be processed only if the packet is for us. 1362 * Returns 1 if packet has been forwarded/freed, 1363 * 0 if the packet should be processed further. 1364 */ 1365 static int 1366 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1367 { 1368 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1369 struct ip *ip = mtod(m, struct ip *); 1370 u_char *cp; 1371 struct in_ifaddr *ia; 1372 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1373 boolean_t forward = FALSE; 1374 struct in_addr *sin, dst; 1375 n_time ntime; 1376 1377 dst = ip->ip_dst; 1378 cp = (u_char *)(ip + 1); 1379 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1380 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1381 opt = cp[IPOPT_OPTVAL]; 1382 if (opt == IPOPT_EOL) 1383 break; 1384 if (opt == IPOPT_NOP) 1385 optlen = 1; 1386 else { 1387 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1388 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1389 goto bad; 1390 } 1391 optlen = cp[IPOPT_OLEN]; 1392 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1393 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1394 goto bad; 1395 } 1396 } 1397 switch (opt) { 1398 1399 default: 1400 break; 1401 1402 /* 1403 * Source routing with record. 1404 * Find interface with current destination address. 1405 * If none on this machine then drop if strictly routed, 1406 * or do nothing if loosely routed. 1407 * Record interface address and bring up next address 1408 * component. If strictly routed make sure next 1409 * address is on directly accessible net. 1410 */ 1411 case IPOPT_LSRR: 1412 case IPOPT_SSRR: 1413 if (ipstealth && pass > 0) 1414 break; 1415 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1416 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1417 goto bad; 1418 } 1419 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1420 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1421 goto bad; 1422 } 1423 ipaddr.sin_addr = ip->ip_dst; 1424 ia = (struct in_ifaddr *) 1425 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1426 if (ia == NULL) { 1427 if (opt == IPOPT_SSRR) { 1428 type = ICMP_UNREACH; 1429 code = ICMP_UNREACH_SRCFAIL; 1430 goto bad; 1431 } 1432 if (!ip_dosourceroute) 1433 goto nosourcerouting; 1434 /* 1435 * Loose routing, and not at next destination 1436 * yet; nothing to do except forward. 1437 */ 1438 break; 1439 } 1440 off--; /* 0 origin */ 1441 if (off > optlen - (int)sizeof(struct in_addr)) { 1442 /* 1443 * End of source route. Should be for us. 1444 */ 1445 if (!ip_acceptsourceroute) 1446 goto nosourcerouting; 1447 save_rte(m, cp, ip->ip_src); 1448 break; 1449 } 1450 if (ipstealth) 1451 goto dropit; 1452 if (!ip_dosourceroute) { 1453 if (ipforwarding) { 1454 char buf[sizeof "aaa.bbb.ccc.ddd"]; 1455 1456 /* 1457 * Acting as a router, so generate ICMP 1458 */ 1459 nosourcerouting: 1460 strcpy(buf, inet_ntoa(ip->ip_dst)); 1461 log(LOG_WARNING, 1462 "attempted source route from %s to %s\n", 1463 inet_ntoa(ip->ip_src), buf); 1464 type = ICMP_UNREACH; 1465 code = ICMP_UNREACH_SRCFAIL; 1466 goto bad; 1467 } else { 1468 /* 1469 * Not acting as a router, 1470 * so silently drop. 1471 */ 1472 dropit: 1473 ipstat.ips_cantforward++; 1474 m_freem(m); 1475 return (1); 1476 } 1477 } 1478 1479 /* 1480 * locate outgoing interface 1481 */ 1482 memcpy(&ipaddr.sin_addr, cp + off, 1483 sizeof ipaddr.sin_addr); 1484 1485 if (opt == IPOPT_SSRR) { 1486 #define INA struct in_ifaddr * 1487 #define SA struct sockaddr * 1488 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1489 == NULL) 1490 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1491 } else { 1492 ia = ip_rtaddr(ipaddr.sin_addr, NULL); 1493 } 1494 if (ia == NULL) { 1495 type = ICMP_UNREACH; 1496 code = ICMP_UNREACH_SRCFAIL; 1497 goto bad; 1498 } 1499 ip->ip_dst = ipaddr.sin_addr; 1500 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1501 sizeof(struct in_addr)); 1502 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1503 /* 1504 * Let ip_intr's mcast routing check handle mcast pkts 1505 */ 1506 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1507 break; 1508 1509 case IPOPT_RR: 1510 if (ipstealth && pass == 0) 1511 break; 1512 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1513 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1514 goto bad; 1515 } 1516 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1517 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1518 goto bad; 1519 } 1520 /* 1521 * If no space remains, ignore. 1522 */ 1523 off--; /* 0 origin */ 1524 if (off > optlen - (int)sizeof(struct in_addr)) 1525 break; 1526 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1527 sizeof ipaddr.sin_addr); 1528 /* 1529 * locate outgoing interface; if we're the destination, 1530 * use the incoming interface (should be same). 1531 */ 1532 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1533 (ia = ip_rtaddr(ipaddr.sin_addr, NULL)) == NULL) { 1534 type = ICMP_UNREACH; 1535 code = ICMP_UNREACH_HOST; 1536 goto bad; 1537 } 1538 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1539 sizeof(struct in_addr)); 1540 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1541 break; 1542 1543 case IPOPT_TS: 1544 if (ipstealth && pass == 0) 1545 break; 1546 code = cp - (u_char *)ip; 1547 if (optlen < 4 || optlen > 40) { 1548 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1549 goto bad; 1550 } 1551 if ((off = cp[IPOPT_OFFSET]) < 5) { 1552 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1553 goto bad; 1554 } 1555 if (off > optlen - (int)sizeof(int32_t)) { 1556 cp[IPOPT_OFFSET + 1] += (1 << 4); 1557 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1558 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1559 goto bad; 1560 } 1561 break; 1562 } 1563 off--; /* 0 origin */ 1564 sin = (struct in_addr *)(cp + off); 1565 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1566 1567 case IPOPT_TS_TSONLY: 1568 break; 1569 1570 case IPOPT_TS_TSANDADDR: 1571 if (off + sizeof(n_time) + 1572 sizeof(struct in_addr) > optlen) { 1573 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1574 goto bad; 1575 } 1576 ipaddr.sin_addr = dst; 1577 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1578 m->m_pkthdr.rcvif); 1579 if (ia == NULL) 1580 continue; 1581 memcpy(sin, &IA_SIN(ia)->sin_addr, 1582 sizeof(struct in_addr)); 1583 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1584 off += sizeof(struct in_addr); 1585 break; 1586 1587 case IPOPT_TS_PRESPEC: 1588 if (off + sizeof(n_time) + 1589 sizeof(struct in_addr) > optlen) { 1590 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1591 goto bad; 1592 } 1593 memcpy(&ipaddr.sin_addr, sin, 1594 sizeof(struct in_addr)); 1595 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1596 continue; 1597 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1598 off += sizeof(struct in_addr); 1599 break; 1600 1601 default: 1602 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1603 goto bad; 1604 } 1605 ntime = iptime(); 1606 memcpy(cp + off, &ntime, sizeof(n_time)); 1607 cp[IPOPT_OFFSET] += sizeof(n_time); 1608 } 1609 } 1610 if (forward && ipforwarding) { 1611 ip_forward(m, TRUE, next_hop); 1612 return (1); 1613 } 1614 return (0); 1615 bad: 1616 icmp_error(m, type, code, 0, 0); 1617 ipstat.ips_badoptions++; 1618 return (1); 1619 } 1620 1621 /* 1622 * Given address of next destination (final or next hop), 1623 * return internet address info of interface to be used to get there. 1624 */ 1625 struct in_ifaddr * 1626 ip_rtaddr(struct in_addr dst, struct route *ro0) 1627 { 1628 struct route sro, *ro; 1629 struct sockaddr_in *sin; 1630 struct in_ifaddr *ia; 1631 1632 if (ro0 != NULL) { 1633 ro = ro0; 1634 } else { 1635 bzero(&sro, sizeof(sro)); 1636 ro = &sro; 1637 } 1638 1639 sin = (struct sockaddr_in *)&ro->ro_dst; 1640 1641 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1642 if (ro->ro_rt != NULL) { 1643 RTFREE(ro->ro_rt); 1644 ro->ro_rt = NULL; 1645 } 1646 sin->sin_family = AF_INET; 1647 sin->sin_len = sizeof *sin; 1648 sin->sin_addr = dst; 1649 rtalloc_ign(ro, RTF_PRCLONING); 1650 } 1651 1652 if (ro->ro_rt == NULL) 1653 return (NULL); 1654 1655 ia = ifatoia(ro->ro_rt->rt_ifa); 1656 1657 if (ro == &sro) 1658 RTFREE(ro->ro_rt); 1659 return ia; 1660 } 1661 1662 /* 1663 * Save incoming source route for use in replies, 1664 * to be picked up later by ip_srcroute if the receiver is interested. 1665 */ 1666 static void 1667 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1668 { 1669 struct m_tag *mtag; 1670 struct ip_srcrt_opt *opt; 1671 unsigned olen; 1672 1673 mtag = m_tag_get(PACKET_TAG_IPSRCRT, sizeof(*opt), MB_DONTWAIT); 1674 if (mtag == NULL) 1675 return; 1676 opt = m_tag_data(mtag); 1677 1678 olen = option[IPOPT_OLEN]; 1679 #ifdef DIAGNOSTIC 1680 if (ipprintfs) 1681 kprintf("save_rte: olen %d\n", olen); 1682 #endif 1683 if (olen > sizeof(opt->ip_srcrt) - (1 + sizeof(dst))) { 1684 m_tag_free(mtag); 1685 return; 1686 } 1687 bcopy(option, opt->ip_srcrt.srcopt, olen); 1688 opt->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1689 opt->ip_srcrt.dst = dst; 1690 m_tag_prepend(m, mtag); 1691 } 1692 1693 /* 1694 * Retrieve incoming source route for use in replies, 1695 * in the same form used by setsockopt. 1696 * The first hop is placed before the options, will be removed later. 1697 */ 1698 struct mbuf * 1699 ip_srcroute(struct mbuf *m0) 1700 { 1701 struct in_addr *p, *q; 1702 struct mbuf *m; 1703 struct m_tag *mtag; 1704 struct ip_srcrt_opt *opt; 1705 1706 if (m0 == NULL) 1707 return NULL; 1708 1709 mtag = m_tag_find(m0, PACKET_TAG_IPSRCRT, NULL); 1710 if (mtag == NULL) 1711 return NULL; 1712 opt = m_tag_data(mtag); 1713 1714 if (opt->ip_nhops == 0) 1715 return (NULL); 1716 m = m_get(MB_DONTWAIT, MT_HEADER); 1717 if (m == NULL) 1718 return (NULL); 1719 1720 #define OPTSIZ (sizeof(opt->ip_srcrt.nop) + sizeof(opt->ip_srcrt.srcopt)) 1721 1722 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1723 m->m_len = opt->ip_nhops * sizeof(struct in_addr) + 1724 sizeof(struct in_addr) + OPTSIZ; 1725 #ifdef DIAGNOSTIC 1726 if (ipprintfs) { 1727 kprintf("ip_srcroute: nhops %d mlen %d", 1728 opt->ip_nhops, m->m_len); 1729 } 1730 #endif 1731 1732 /* 1733 * First save first hop for return route 1734 */ 1735 p = &opt->ip_srcrt.route[opt->ip_nhops - 1]; 1736 *(mtod(m, struct in_addr *)) = *p--; 1737 #ifdef DIAGNOSTIC 1738 if (ipprintfs) 1739 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1740 #endif 1741 1742 /* 1743 * Copy option fields and padding (nop) to mbuf. 1744 */ 1745 opt->ip_srcrt.nop = IPOPT_NOP; 1746 opt->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1747 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &opt->ip_srcrt.nop, 1748 OPTSIZ); 1749 q = (struct in_addr *)(mtod(m, caddr_t) + 1750 sizeof(struct in_addr) + OPTSIZ); 1751 #undef OPTSIZ 1752 /* 1753 * Record return path as an IP source route, 1754 * reversing the path (pointers are now aligned). 1755 */ 1756 while (p >= opt->ip_srcrt.route) { 1757 #ifdef DIAGNOSTIC 1758 if (ipprintfs) 1759 kprintf(" %x", ntohl(q->s_addr)); 1760 #endif 1761 *q++ = *p--; 1762 } 1763 /* 1764 * Last hop goes to final destination. 1765 */ 1766 *q = opt->ip_srcrt.dst; 1767 m_tag_delete(m0, mtag); 1768 #ifdef DIAGNOSTIC 1769 if (ipprintfs) 1770 kprintf(" %x\n", ntohl(q->s_addr)); 1771 #endif 1772 return (m); 1773 } 1774 1775 /* 1776 * Strip out IP options. 1777 */ 1778 void 1779 ip_stripoptions(struct mbuf *m) 1780 { 1781 int datalen; 1782 struct ip *ip = mtod(m, struct ip *); 1783 caddr_t opts; 1784 int optlen; 1785 1786 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1787 opts = (caddr_t)(ip + 1); 1788 datalen = m->m_len - (sizeof(struct ip) + optlen); 1789 bcopy(opts + optlen, opts, datalen); 1790 m->m_len -= optlen; 1791 if (m->m_flags & M_PKTHDR) 1792 m->m_pkthdr.len -= optlen; 1793 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1794 } 1795 1796 u_char inetctlerrmap[PRC_NCMDS] = { 1797 0, 0, 0, 0, 1798 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1799 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1800 EMSGSIZE, EHOSTUNREACH, 0, 0, 1801 0, 0, 0, 0, 1802 ENOPROTOOPT, ECONNREFUSED 1803 }; 1804 1805 /* 1806 * Forward a packet. If some error occurs return the sender 1807 * an icmp packet. Note we can't always generate a meaningful 1808 * icmp message because icmp doesn't have a large enough repertoire 1809 * of codes and types. 1810 * 1811 * If not forwarding, just drop the packet. This could be confusing 1812 * if ipforwarding was zero but some routing protocol was advancing 1813 * us as a gateway to somewhere. However, we must let the routing 1814 * protocol deal with that. 1815 * 1816 * The using_srcrt parameter indicates whether the packet is being forwarded 1817 * via a source route. 1818 */ 1819 void 1820 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop) 1821 { 1822 struct ip *ip = mtod(m, struct ip *); 1823 struct rtentry *rt; 1824 struct route fwd_ro; 1825 int error, type = 0, code = 0, destmtu = 0; 1826 struct mbuf *mcopy; 1827 n_long dest; 1828 struct in_addr pkt_dst; 1829 1830 dest = INADDR_ANY; 1831 /* 1832 * Cache the destination address of the packet; this may be 1833 * changed by use of 'ipfw fwd'. 1834 */ 1835 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 1836 1837 #ifdef DIAGNOSTIC 1838 if (ipprintfs) 1839 kprintf("forward: src %x dst %x ttl %x\n", 1840 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1841 #endif 1842 1843 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1844 ipstat.ips_cantforward++; 1845 m_freem(m); 1846 return; 1847 } 1848 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1849 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1850 return; 1851 } 1852 1853 bzero(&fwd_ro, sizeof(fwd_ro)); 1854 ip_rtaddr(pkt_dst, &fwd_ro); 1855 if (fwd_ro.ro_rt == NULL) { 1856 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1857 return; 1858 } 1859 rt = fwd_ro.ro_rt; 1860 1861 /* 1862 * Save the IP header and at most 8 bytes of the payload, 1863 * in case we need to generate an ICMP message to the src. 1864 * 1865 * XXX this can be optimized a lot by saving the data in a local 1866 * buffer on the stack (72 bytes at most), and only allocating the 1867 * mbuf if really necessary. The vast majority of the packets 1868 * are forwarded without having to send an ICMP back (either 1869 * because unnecessary, or because rate limited), so we are 1870 * really we are wasting a lot of work here. 1871 * 1872 * We don't use m_copy() because it might return a reference 1873 * to a shared cluster. Both this function and ip_output() 1874 * assume exclusive access to the IP header in `m', so any 1875 * data in a cluster may change before we reach icmp_error(). 1876 */ 1877 MGETHDR(mcopy, MB_DONTWAIT, m->m_type); 1878 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) { 1879 /* 1880 * It's probably ok if the pkthdr dup fails (because 1881 * the deep copy of the tag chain failed), but for now 1882 * be conservative and just discard the copy since 1883 * code below may some day want the tags. 1884 */ 1885 m_free(mcopy); 1886 mcopy = NULL; 1887 } 1888 if (mcopy != NULL) { 1889 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1890 (int)ip->ip_len); 1891 mcopy->m_pkthdr.len = mcopy->m_len; 1892 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1893 } 1894 1895 if (!ipstealth) 1896 ip->ip_ttl -= IPTTLDEC; 1897 1898 /* 1899 * If forwarding packet using same interface that it came in on, 1900 * perhaps should send a redirect to sender to shortcut a hop. 1901 * Only send redirect if source is sending directly to us, 1902 * and if packet was not source routed (or has any options). 1903 * Also, don't send redirect if forwarding using a default route 1904 * or a route modified by a redirect. 1905 */ 1906 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1907 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1908 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1909 ipsendredirects && !using_srcrt && next_hop == NULL) { 1910 u_long src = ntohl(ip->ip_src.s_addr); 1911 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa; 1912 1913 if (rt_ifa != NULL && 1914 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) { 1915 if (rt->rt_flags & RTF_GATEWAY) 1916 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1917 else 1918 dest = pkt_dst.s_addr; 1919 /* 1920 * Router requirements says to only send 1921 * host redirects. 1922 */ 1923 type = ICMP_REDIRECT; 1924 code = ICMP_REDIRECT_HOST; 1925 #ifdef DIAGNOSTIC 1926 if (ipprintfs) 1927 kprintf("redirect (%d) to %x\n", code, dest); 1928 #endif 1929 } 1930 } 1931 1932 error = ip_output(m, NULL, &fwd_ro, IP_FORWARDING, NULL, NULL); 1933 if (error == 0) { 1934 ipstat.ips_forward++; 1935 if (type == 0) { 1936 if (mcopy) { 1937 ipflow_create(&fwd_ro, mcopy); 1938 m_freem(mcopy); 1939 } 1940 goto done; 1941 } else { 1942 ipstat.ips_redirectsent++; 1943 } 1944 } else { 1945 ipstat.ips_cantforward++; 1946 } 1947 1948 if (mcopy == NULL) 1949 goto done; 1950 1951 /* 1952 * Send ICMP message. 1953 */ 1954 1955 switch (error) { 1956 1957 case 0: /* forwarded, but need redirect */ 1958 /* type, code set above */ 1959 break; 1960 1961 case ENETUNREACH: /* shouldn't happen, checked above */ 1962 case EHOSTUNREACH: 1963 case ENETDOWN: 1964 case EHOSTDOWN: 1965 default: 1966 type = ICMP_UNREACH; 1967 code = ICMP_UNREACH_HOST; 1968 break; 1969 1970 case EMSGSIZE: 1971 type = ICMP_UNREACH; 1972 code = ICMP_UNREACH_NEEDFRAG; 1973 #ifdef IPSEC 1974 /* 1975 * If the packet is routed over IPsec tunnel, tell the 1976 * originator the tunnel MTU. 1977 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1978 * XXX quickhack!!! 1979 */ 1980 if (fwd_ro.ro_rt != NULL) { 1981 struct secpolicy *sp = NULL; 1982 int ipsecerror; 1983 int ipsechdr; 1984 struct route *ro; 1985 1986 sp = ipsec4_getpolicybyaddr(mcopy, 1987 IPSEC_DIR_OUTBOUND, 1988 IP_FORWARDING, 1989 &ipsecerror); 1990 1991 if (sp == NULL) 1992 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 1993 else { 1994 /* count IPsec header size */ 1995 ipsechdr = ipsec4_hdrsiz(mcopy, 1996 IPSEC_DIR_OUTBOUND, 1997 NULL); 1998 1999 /* 2000 * find the correct route for outer IPv4 2001 * header, compute tunnel MTU. 2002 * 2003 */ 2004 if (sp->req != NULL && sp->req->sav != NULL && 2005 sp->req->sav->sah != NULL) { 2006 ro = &sp->req->sav->sah->sa_route; 2007 if (ro->ro_rt != NULL && 2008 ro->ro_rt->rt_ifp != NULL) { 2009 destmtu = 2010 ro->ro_rt->rt_ifp->if_mtu; 2011 destmtu -= ipsechdr; 2012 } 2013 } 2014 2015 key_freesp(sp); 2016 } 2017 } 2018 #elif FAST_IPSEC 2019 /* 2020 * If the packet is routed over IPsec tunnel, tell the 2021 * originator the tunnel MTU. 2022 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2023 * XXX quickhack!!! 2024 */ 2025 if (fwd_ro.ro_rt != NULL) { 2026 struct secpolicy *sp = NULL; 2027 int ipsecerror; 2028 int ipsechdr; 2029 struct route *ro; 2030 2031 sp = ipsec_getpolicybyaddr(mcopy, 2032 IPSEC_DIR_OUTBOUND, 2033 IP_FORWARDING, 2034 &ipsecerror); 2035 2036 if (sp == NULL) 2037 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2038 else { 2039 /* count IPsec header size */ 2040 ipsechdr = ipsec4_hdrsiz(mcopy, 2041 IPSEC_DIR_OUTBOUND, 2042 NULL); 2043 2044 /* 2045 * find the correct route for outer IPv4 2046 * header, compute tunnel MTU. 2047 */ 2048 2049 if (sp->req != NULL && 2050 sp->req->sav != NULL && 2051 sp->req->sav->sah != NULL) { 2052 ro = &sp->req->sav->sah->sa_route; 2053 if (ro->ro_rt != NULL && 2054 ro->ro_rt->rt_ifp != NULL) { 2055 destmtu = 2056 ro->ro_rt->rt_ifp->if_mtu; 2057 destmtu -= ipsechdr; 2058 } 2059 } 2060 2061 KEY_FREESP(&sp); 2062 } 2063 } 2064 #else /* !IPSEC && !FAST_IPSEC */ 2065 if (fwd_ro.ro_rt != NULL) 2066 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2067 #endif /*IPSEC*/ 2068 ipstat.ips_cantfrag++; 2069 break; 2070 2071 case ENOBUFS: 2072 /* 2073 * A router should not generate ICMP_SOURCEQUENCH as 2074 * required in RFC1812 Requirements for IP Version 4 Routers. 2075 * Source quench could be a big problem under DoS attacks, 2076 * or if the underlying interface is rate-limited. 2077 * Those who need source quench packets may re-enable them 2078 * via the net.inet.ip.sendsourcequench sysctl. 2079 */ 2080 if (!ip_sendsourcequench) { 2081 m_freem(mcopy); 2082 goto done; 2083 } else { 2084 type = ICMP_SOURCEQUENCH; 2085 code = 0; 2086 } 2087 break; 2088 2089 case EACCES: /* ipfw denied packet */ 2090 m_freem(mcopy); 2091 goto done; 2092 } 2093 icmp_error(mcopy, type, code, dest, destmtu); 2094 done: 2095 if (fwd_ro.ro_rt != NULL) 2096 RTFREE(fwd_ro.ro_rt); 2097 } 2098 2099 void 2100 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2101 struct mbuf *m) 2102 { 2103 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2104 struct timeval tv; 2105 2106 microtime(&tv); 2107 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2108 SCM_TIMESTAMP, SOL_SOCKET); 2109 if (*mp) 2110 mp = &(*mp)->m_next; 2111 } 2112 if (inp->inp_flags & INP_RECVDSTADDR) { 2113 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2114 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2115 if (*mp) 2116 mp = &(*mp)->m_next; 2117 } 2118 if (inp->inp_flags & INP_RECVTTL) { 2119 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2120 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2121 if (*mp) 2122 mp = &(*mp)->m_next; 2123 } 2124 #ifdef notyet 2125 /* XXX 2126 * Moving these out of udp_input() made them even more broken 2127 * than they already were. 2128 */ 2129 /* options were tossed already */ 2130 if (inp->inp_flags & INP_RECVOPTS) { 2131 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2132 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2133 if (*mp) 2134 mp = &(*mp)->m_next; 2135 } 2136 /* ip_srcroute doesn't do what we want here, need to fix */ 2137 if (inp->inp_flags & INP_RECVRETOPTS) { 2138 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 2139 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2140 if (*mp) 2141 mp = &(*mp)->m_next; 2142 } 2143 #endif 2144 if (inp->inp_flags & INP_RECVIF) { 2145 struct ifnet *ifp; 2146 struct sdlbuf { 2147 struct sockaddr_dl sdl; 2148 u_char pad[32]; 2149 } sdlbuf; 2150 struct sockaddr_dl *sdp; 2151 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2152 2153 if (((ifp = m->m_pkthdr.rcvif)) && 2154 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2155 sdp = IF_LLSOCKADDR(ifp); 2156 /* 2157 * Change our mind and don't try copy. 2158 */ 2159 if ((sdp->sdl_family != AF_LINK) || 2160 (sdp->sdl_len > sizeof(sdlbuf))) { 2161 goto makedummy; 2162 } 2163 bcopy(sdp, sdl2, sdp->sdl_len); 2164 } else { 2165 makedummy: 2166 sdl2->sdl_len = 2167 offsetof(struct sockaddr_dl, sdl_data[0]); 2168 sdl2->sdl_family = AF_LINK; 2169 sdl2->sdl_index = 0; 2170 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2171 } 2172 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2173 IP_RECVIF, IPPROTO_IP); 2174 if (*mp) 2175 mp = &(*mp)->m_next; 2176 } 2177 } 2178 2179 /* 2180 * XXX these routines are called from the upper part of the kernel. 2181 * 2182 * They could also be moved to ip_mroute.c, since all the RSVP 2183 * handling is done there already. 2184 */ 2185 int 2186 ip_rsvp_init(struct socket *so) 2187 { 2188 if (so->so_type != SOCK_RAW || 2189 so->so_proto->pr_protocol != IPPROTO_RSVP) 2190 return EOPNOTSUPP; 2191 2192 if (ip_rsvpd != NULL) 2193 return EADDRINUSE; 2194 2195 ip_rsvpd = so; 2196 /* 2197 * This may seem silly, but we need to be sure we don't over-increment 2198 * the RSVP counter, in case something slips up. 2199 */ 2200 if (!ip_rsvp_on) { 2201 ip_rsvp_on = 1; 2202 rsvp_on++; 2203 } 2204 2205 return 0; 2206 } 2207 2208 int 2209 ip_rsvp_done(void) 2210 { 2211 ip_rsvpd = NULL; 2212 /* 2213 * This may seem silly, but we need to be sure we don't over-decrement 2214 * the RSVP counter, in case something slips up. 2215 */ 2216 if (ip_rsvp_on) { 2217 ip_rsvp_on = 0; 2218 rsvp_on--; 2219 } 2220 return 0; 2221 } 2222 2223 void 2224 rsvp_input(struct mbuf *m, ...) /* XXX must fixup manually */ 2225 { 2226 int off, proto; 2227 __va_list ap; 2228 2229 __va_start(ap, m); 2230 off = __va_arg(ap, int); 2231 proto = __va_arg(ap, int); 2232 __va_end(ap); 2233 2234 if (rsvp_input_p) { /* call the real one if loaded */ 2235 rsvp_input_p(m, off, proto); 2236 return; 2237 } 2238 2239 /* Can still get packets with rsvp_on = 0 if there is a local member 2240 * of the group to which the RSVP packet is addressed. But in this 2241 * case we want to throw the packet away. 2242 */ 2243 2244 if (!rsvp_on) { 2245 m_freem(m); 2246 return; 2247 } 2248 2249 if (ip_rsvpd != NULL) { 2250 rip_input(m, off, proto); 2251 return; 2252 } 2253 /* Drop the packet */ 2254 m_freem(m); 2255 } 2256