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 1.98 2008/09/06 14:12:50 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 97 #include <machine/stdarg.h> 98 99 #include <net/if.h> 100 #include <net/if_types.h> 101 #include <net/if_var.h> 102 #include <net/if_dl.h> 103 #include <net/pfil.h> 104 #include <net/route.h> 105 #include <net/netisr.h> 106 107 #include <netinet/in.h> 108 #include <netinet/in_systm.h> 109 #include <netinet/in_var.h> 110 #include <netinet/ip.h> 111 #include <netinet/in_pcb.h> 112 #include <netinet/ip_var.h> 113 #include <netinet/ip_icmp.h> 114 #ifdef IPDIVERT 115 #include <netinet/ip_divert.h> 116 #endif 117 118 #include <sys/thread2.h> 119 #include <sys/msgport2.h> 120 #include <net/netmsg2.h> 121 122 #include <sys/socketvar.h> 123 124 #include <net/ipfw/ip_fw.h> 125 #include <net/dummynet/ip_dummynet.h> 126 127 #ifdef IPSEC 128 #include <netinet6/ipsec.h> 129 #include <netproto/key/key.h> 130 #endif 131 132 #ifdef FAST_IPSEC 133 #include <netproto/ipsec/ipsec.h> 134 #include <netproto/ipsec/key.h> 135 #endif 136 137 int rsvp_on = 0; 138 static int ip_rsvp_on; 139 struct socket *ip_rsvpd; 140 141 int ipforwarding = 0; 142 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 143 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 144 145 static int ipsendredirects = 1; /* XXX */ 146 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 147 &ipsendredirects, 0, "Enable sending IP redirects"); 148 149 int ip_defttl = IPDEFTTL; 150 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 151 &ip_defttl, 0, "Maximum TTL on IP packets"); 152 153 static int ip_dosourceroute = 0; 154 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 155 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 156 157 static int ip_acceptsourceroute = 0; 158 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 159 CTLFLAG_RW, &ip_acceptsourceroute, 0, 160 "Enable accepting source routed IP packets"); 161 162 static int ip_keepfaith = 0; 163 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 164 &ip_keepfaith, 0, 165 "Enable packet capture for FAITH IPv4->IPv6 translator daemon"); 166 167 static int nipq = 0; /* total # of reass queues */ 168 static int maxnipq; 169 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 170 &maxnipq, 0, 171 "Maximum number of IPv4 fragment reassembly queue entries"); 172 173 static int maxfragsperpacket; 174 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 175 &maxfragsperpacket, 0, 176 "Maximum number of IPv4 fragments allowed per packet"); 177 178 static int ip_sendsourcequench = 0; 179 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 180 &ip_sendsourcequench, 0, 181 "Enable the transmission of source quench packets"); 182 183 int ip_do_randomid = 1; 184 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 185 &ip_do_randomid, 0, 186 "Assign random ip_id values"); 187 /* 188 * XXX - Setting ip_checkinterface mostly implements the receive side of 189 * the Strong ES model described in RFC 1122, but since the routing table 190 * and transmit implementation do not implement the Strong ES model, 191 * setting this to 1 results in an odd hybrid. 192 * 193 * XXX - ip_checkinterface currently must be disabled if you use ipnat 194 * to translate the destination address to another local interface. 195 * 196 * XXX - ip_checkinterface must be disabled if you add IP aliases 197 * to the loopback interface instead of the interface where the 198 * packets for those addresses are received. 199 */ 200 static int ip_checkinterface = 0; 201 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 202 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 203 204 #ifdef DIAGNOSTIC 205 static int ipprintfs = 0; 206 #endif 207 208 extern struct domain inetdomain; 209 extern struct protosw inetsw[]; 210 u_char ip_protox[IPPROTO_MAX]; 211 struct in_ifaddrhead in_ifaddrheads[MAXCPU]; /* first inet address */ 212 struct in_ifaddrhashhead *in_ifaddrhashtbls[MAXCPU]; 213 /* inet addr hash table */ 214 u_long in_ifaddrhmask; /* mask for hash table */ 215 216 struct ip_stats ipstats_percpu[MAXCPU]; 217 #ifdef SMP 218 static int 219 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 220 { 221 int cpu, error = 0; 222 223 for (cpu = 0; cpu < ncpus; ++cpu) { 224 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu], 225 sizeof(struct ip_stats)))) 226 break; 227 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu], 228 sizeof(struct ip_stats)))) 229 break; 230 } 231 232 return (error); 233 } 234 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 235 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 236 #else 237 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 238 &ipstat, ip_stats, "IP statistics"); 239 #endif 240 241 /* Packet reassembly stuff */ 242 #define IPREASS_NHASH_LOG2 6 243 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 244 #define IPREASS_HMASK (IPREASS_NHASH - 1) 245 #define IPREASS_HASH(x,y) \ 246 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 247 248 static struct ipq ipq[IPREASS_NHASH]; 249 250 #ifdef IPCTL_DEFMTU 251 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 252 &ip_mtu, 0, "Default MTU"); 253 #endif 254 255 #ifdef IPSTEALTH 256 static int ipstealth = 0; 257 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, ""); 258 #else 259 static const int ipstealth = 0; 260 #endif 261 262 263 /* Firewall hooks */ 264 ip_fw_chk_t *ip_fw_chk_ptr; 265 ip_fw_dn_io_t *ip_fw_dn_io_ptr; 266 int ip_fw_loaded; 267 int fw_enable = 1; 268 int fw_one_pass = 1; 269 270 struct pfil_head inet_pfil_hook; 271 272 /* 273 * struct ip_srcrt_opt is used to store packet state while it travels 274 * through the stack. 275 * 276 * XXX Note that the code even makes assumptions on the size and 277 * alignment of fields inside struct ip_srcrt so e.g. adding some 278 * fields will break the code. This needs to be fixed. 279 * 280 * We need to save the IP options in case a protocol wants to respond 281 * to an incoming packet over the same route if the packet got here 282 * using IP source routing. This allows connection establishment and 283 * maintenance when the remote end is on a network that is not known 284 * to us. 285 */ 286 struct ip_srcrt { 287 struct in_addr dst; /* final destination */ 288 char nop; /* one NOP to align */ 289 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 290 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 291 }; 292 293 struct ip_srcrt_opt { 294 int ip_nhops; 295 struct ip_srcrt ip_srcrt; 296 }; 297 298 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 299 static struct malloc_pipe ipq_mpipe; 300 301 static void save_rte(struct mbuf *, u_char *, struct in_addr); 302 static int ip_dooptions(struct mbuf *m, int, struct sockaddr_in *); 303 static void ip_freef(struct ipq *); 304 static void ip_input_handler(struct netmsg *); 305 static struct mbuf *ip_reass(struct mbuf *); 306 307 /* 308 * IP initialization: fill in IP protocol switch table. 309 * All protocols not implemented in kernel go to raw IP protocol handler. 310 */ 311 void 312 ip_init(void) 313 { 314 struct protosw *pr; 315 int i; 316 #ifdef SMP 317 int cpu; 318 #endif 319 320 /* 321 * Make sure we can handle a reasonable number of fragments but 322 * cap it at 4000 (XXX). 323 */ 324 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 325 IFQ_MAXLEN, 4000, 0, NULL); 326 for (i = 0; i < ncpus; ++i) { 327 TAILQ_INIT(&in_ifaddrheads[i]); 328 in_ifaddrhashtbls[i] = 329 hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 330 } 331 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 332 if (pr == NULL) 333 panic("ip_init"); 334 for (i = 0; i < IPPROTO_MAX; i++) 335 ip_protox[i] = pr - inetsw; 336 for (pr = inetdomain.dom_protosw; 337 pr < inetdomain.dom_protoswNPROTOSW; pr++) 338 if (pr->pr_domain->dom_family == PF_INET && 339 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 340 ip_protox[pr->pr_protocol] = pr - inetsw; 341 342 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 343 inet_pfil_hook.ph_af = AF_INET; 344 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) { 345 kprintf("%s: WARNING: unable to register pfil hook, " 346 "error %d\n", __func__, i); 347 } 348 349 for (i = 0; i < IPREASS_NHASH; i++) 350 ipq[i].next = ipq[i].prev = &ipq[i]; 351 352 maxnipq = nmbclusters / 32; 353 maxfragsperpacket = 16; 354 355 ip_id = time_second & 0xffff; 356 357 /* 358 * Initialize IP statistics counters for each CPU. 359 * 360 */ 361 #ifdef SMP 362 for (cpu = 0; cpu < ncpus; ++cpu) { 363 bzero(&ipstats_percpu[cpu], sizeof(struct ip_stats)); 364 } 365 #else 366 bzero(&ipstat, sizeof(struct ip_stats)); 367 #endif 368 369 netisr_register(NETISR_IP, ip_mport_in, ip_input_handler); 370 } 371 372 /* 373 * XXX watch out this one. It is perhaps used as a cache for 374 * the most recently used route ? it is cleared in in_addroute() 375 * when a new route is successfully created. 376 */ 377 struct route ipforward_rt[MAXCPU]; 378 379 /* Do transport protocol processing. */ 380 static void 381 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip) 382 { 383 /* 384 * Switch out to protocol's input routine. 385 */ 386 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, ip->ip_p); 387 } 388 389 static void 390 transport_processing_handler(netmsg_t netmsg) 391 { 392 struct netmsg_packet *pmsg = (struct netmsg_packet *)netmsg; 393 struct ip *ip; 394 int hlen; 395 396 ip = mtod(pmsg->nm_packet, struct ip *); 397 hlen = pmsg->nm_netmsg.nm_lmsg.u.ms_result; 398 399 transport_processing_oncpu(pmsg->nm_packet, hlen, ip); 400 /* netmsg was embedded in the mbuf, do not reply! */ 401 } 402 403 static void 404 ip_input_handler(struct netmsg *msg0) 405 { 406 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet; 407 408 ip_input(m); 409 /* msg0 was embedded in the mbuf, do not reply! */ 410 } 411 412 /* 413 * IP input routine. Checksum and byte swap header. If fragmented 414 * try to reassemble. Process options. Pass to next level. 415 */ 416 void 417 ip_input(struct mbuf *m) 418 { 419 struct ip *ip; 420 struct in_ifaddr *ia = NULL; 421 struct in_ifaddr_container *iac; 422 int i, hlen, checkif; 423 u_short sum; 424 struct in_addr pkt_dst; 425 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 426 boolean_t needredispatch = FALSE; 427 struct in_addr odst; /* original dst address(NAT) */ 428 struct m_tag *mtag; 429 struct sockaddr_in *next_hop = NULL; 430 #ifdef FAST_IPSEC 431 struct tdb_ident *tdbi; 432 struct secpolicy *sp; 433 int error; 434 #endif 435 436 M_ASSERTPKTHDR(m); 437 438 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 439 /* Next hop */ 440 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 441 KKASSERT(mtag != NULL); 442 next_hop = m_tag_data(mtag); 443 } 444 445 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 446 /* dummynet already filtered us */ 447 ip = mtod(m, struct ip *); 448 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 449 goto iphack; 450 } 451 452 ipstat.ips_total++; 453 454 /* length checks already done in ip_demux() */ 455 KASSERT(m->m_len >= sizeof(ip), ("IP header not in one mbuf")); 456 457 ip = mtod(m, struct ip *); 458 459 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 460 ipstat.ips_badvers++; 461 goto bad; 462 } 463 464 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 465 /* length checks already done in ip_demux() */ 466 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 467 KASSERT(m->m_len >= hlen, ("packet shorter than IP header length")); 468 469 /* 127/8 must not appear on wire - RFC1122 */ 470 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 471 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 472 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 473 ipstat.ips_badaddr++; 474 goto bad; 475 } 476 } 477 478 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 479 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 480 } else { 481 if (hlen == sizeof(struct ip)) { 482 sum = in_cksum_hdr(ip); 483 } else { 484 sum = in_cksum(m, hlen); 485 } 486 } 487 if (sum != 0) { 488 ipstat.ips_badsum++; 489 goto bad; 490 } 491 492 #ifdef ALTQ 493 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 494 /* packet is dropped by traffic conditioner */ 495 return; 496 } 497 #endif 498 /* 499 * Convert fields to host representation. 500 */ 501 ip->ip_len = ntohs(ip->ip_len); 502 if (ip->ip_len < hlen) { 503 ipstat.ips_badlen++; 504 goto bad; 505 } 506 ip->ip_off = ntohs(ip->ip_off); 507 508 /* 509 * Check that the amount of data in the buffers 510 * is as at least much as the IP header would have us expect. 511 * Trim mbufs if longer than we expect. 512 * Drop packet if shorter than we expect. 513 */ 514 if (m->m_pkthdr.len < ip->ip_len) { 515 ipstat.ips_tooshort++; 516 goto bad; 517 } 518 if (m->m_pkthdr.len > ip->ip_len) { 519 if (m->m_len == m->m_pkthdr.len) { 520 m->m_len = ip->ip_len; 521 m->m_pkthdr.len = ip->ip_len; 522 } else 523 m_adj(m, ip->ip_len - m->m_pkthdr.len); 524 } 525 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 526 /* 527 * Bypass packet filtering for packets from a tunnel (gif). 528 */ 529 if (ipsec_gethist(m, NULL)) 530 goto pass; 531 #endif 532 533 /* 534 * IpHack's section. 535 * Right now when no processing on packet has done 536 * and it is still fresh out of network we do our black 537 * deals with it. 538 * - Firewall: deny/allow/divert 539 * - Xlate: translate packet's addr/port (NAT). 540 * - Pipe: pass pkt through dummynet. 541 * - Wrap: fake packet's addr/port <unimpl.> 542 * - Encapsulate: put it in another IP and send out. <unimp.> 543 */ 544 545 iphack: 546 547 /* 548 * Run through list of hooks for input packets. 549 * 550 * NB: Beware of the destination address changing (e.g. 551 * by NAT rewriting). When this happens, tell 552 * ip_forward to do the right thing. 553 */ 554 if (pfil_has_hooks(&inet_pfil_hook)) { 555 odst = ip->ip_dst; 556 if (pfil_run_hooks(&inet_pfil_hook, &m, 557 m->m_pkthdr.rcvif, PFIL_IN)) { 558 return; 559 } 560 if (m == NULL) /* consumed by filter */ 561 return; 562 ip = mtod(m, struct ip *); 563 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 564 } 565 566 if (fw_enable && IPFW_LOADED) { 567 struct ip_fw_args args; 568 569 /* 570 * If we've been forwarded from the output side, then 571 * skip the firewall a second time 572 */ 573 if (next_hop != NULL) 574 goto ours; 575 576 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 577 /* Extract info from dummynet tag */ 578 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL); 579 KKASSERT(mtag != NULL); 580 args.rule = 581 ((struct dn_pkt *)m_tag_data(mtag))->dn_priv; 582 KKASSERT(args.rule != NULL); 583 584 m_tag_delete(m, mtag); 585 m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED; 586 } else { 587 args.rule = NULL; 588 } 589 590 args.eh = NULL; 591 args.oif = NULL; 592 args.m = m; 593 i = ip_fw_chk_ptr(&args); 594 m = args.m; 595 596 if ((i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 597 if (m != NULL) 598 m_freem(m); 599 return; 600 } 601 ip = mtod(m, struct ip *); /* just in case m changed */ 602 603 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 604 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 605 KKASSERT(mtag != NULL); 606 next_hop = m_tag_data(mtag); 607 } 608 609 if (i == 0 && next_hop == NULL) /* common case */ 610 goto pass; 611 if (i & IP_FW_PORT_DYNT_FLAG) { 612 /* Send packet to the appropriate pipe */ 613 ip_fw_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 614 return; 615 } 616 #ifdef IPDIVERT 617 if (i != 0 && !(i & IP_FW_PORT_DYNT_FLAG)) { 618 struct mbuf *clone = NULL; 619 int tee = 0; 620 621 /* Divert or 'tee'? */ 622 if (i & IP_FW_PORT_TEE_FLAG) 623 tee = 1; 624 625 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 626 const struct divert_info *divinfo; 627 u_short frag_off; 628 629 /* 630 * Only trust divert info in the fragment 631 * at offset 0. 632 */ 633 frag_off = ip->ip_off << 3; 634 if (frag_off != 0) { 635 mtag = m_tag_find(m, 636 PACKET_TAG_IPFW_DIVERT, NULL); 637 m_tag_delete(m, mtag); 638 } 639 640 /* 641 * Attempt reassembly; if it succeeds, proceed. 642 * ip_reass() will return a different mbuf. 643 */ 644 m = ip_reass(m); 645 if (m == NULL) 646 return; 647 ip = mtod(m, struct ip *); 648 649 needredispatch = TRUE; 650 651 /* 652 * Get the header length of the reassembled 653 * packet 654 */ 655 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 656 657 /* 658 * Restore original checksum before diverting 659 * packet 660 */ 661 ip->ip_len += hlen; 662 ip->ip_len = htons(ip->ip_len); 663 ip->ip_off = htons(ip->ip_off); 664 ip->ip_sum = 0; 665 if (hlen == sizeof(struct ip)) 666 ip->ip_sum = in_cksum_hdr(ip); 667 else 668 ip->ip_sum = in_cksum(m, hlen); 669 ip->ip_off = ntohs(ip->ip_off); 670 ip->ip_len = ntohs(ip->ip_len); 671 672 /* 673 * Only use the saved divert info 674 */ 675 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, 676 NULL); 677 if (mtag == NULL) { 678 /* Wrongly configured ipfw */ 679 kprintf("ip_input no divert info\n"); 680 m_freem(m); 681 return; 682 } 683 divinfo = m_tag_data(mtag); 684 tee = divinfo->tee; 685 } 686 687 /* 688 * Divert or tee packet to the divert protocol if 689 * required. 690 */ 691 692 /* Clone packet if we're doing a 'tee' */ 693 if (tee) 694 clone = m_dup(m, MB_DONTWAIT); 695 696 /* 697 * Restore packet header fields to original 698 * values 699 */ 700 ip->ip_len = htons(ip->ip_len); 701 ip->ip_off = htons(ip->ip_off); 702 703 /* Deliver packet to divert input routine */ 704 divert_packet(m, 1); 705 ipstat.ips_delivered++; 706 707 /* If 'tee', continue with original packet */ 708 if (clone == NULL) 709 return; 710 m = clone; 711 ip = mtod(m, struct ip *); 712 713 /* 714 * Complete processing of the packet. 715 * 716 * XXX 717 * Better safe than sorry, remove the DIVERT 718 * tag. 719 */ 720 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, 721 NULL); 722 KKASSERT(mtag != NULL); 723 m_tag_delete(m, mtag); 724 725 goto pass; 726 } 727 #endif 728 if (i == 0 && next_hop != NULL) 729 goto pass; 730 /* 731 * if we get here, the packet must be dropped 732 */ 733 m_freem(m); 734 return; 735 } 736 pass: 737 738 /* 739 * Process options and, if not destined for us, 740 * ship it on. ip_dooptions returns 1 when an 741 * error was detected (causing an icmp message 742 * to be sent and the original packet to be freed). 743 */ 744 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, next_hop)) 745 return; 746 747 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 748 * matter if it is destined to another node, or whether it is 749 * a multicast one, RSVP wants it! and prevents it from being forwarded 750 * anywhere else. Also checks if the rsvp daemon is running before 751 * grabbing the packet. 752 */ 753 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 754 goto ours; 755 756 /* 757 * Check our list of addresses, to see if the packet is for us. 758 * If we don't have any addresses, assume any unicast packet 759 * we receive might be for us (and let the upper layers deal 760 * with it). 761 */ 762 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) && 763 !(m->m_flags & (M_MCAST | M_BCAST))) 764 goto ours; 765 766 /* 767 * Cache the destination address of the packet; this may be 768 * changed by use of 'ipfw fwd'. 769 */ 770 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 771 772 /* 773 * Enable a consistency check between the destination address 774 * and the arrival interface for a unicast packet (the RFC 1122 775 * strong ES model) if IP forwarding is disabled and the packet 776 * is not locally generated and the packet is not subject to 777 * 'ipfw fwd'. 778 * 779 * XXX - Checking also should be disabled if the destination 780 * address is ipnat'ed to a different interface. 781 * 782 * XXX - Checking is incompatible with IP aliases added 783 * to the loopback interface instead of the interface where 784 * the packets are received. 785 */ 786 checkif = ip_checkinterface && 787 !ipforwarding && 788 m->m_pkthdr.rcvif != NULL && 789 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 790 next_hop == NULL; 791 792 /* 793 * Check for exact addresses in the hash bucket. 794 */ 795 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 796 ia = iac->ia; 797 798 /* 799 * If the address matches, verify that the packet 800 * arrived via the correct interface if checking is 801 * enabled. 802 */ 803 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 804 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 805 goto ours; 806 } 807 ia = NULL; 808 809 /* 810 * Check for broadcast addresses. 811 * 812 * Only accept broadcast packets that arrive via the matching 813 * interface. Reception of forwarded directed broadcasts would 814 * be handled via ip_forward() and ether_output() with the loopback 815 * into the stack for SIMPLEX interfaces handled by ether_output(). 816 */ 817 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 818 struct ifaddr_container *ifac; 819 820 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 821 ifa_link) { 822 struct ifaddr *ifa = ifac->ifa; 823 824 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 825 continue; 826 if (ifa->ifa_addr->sa_family != AF_INET) 827 continue; 828 ia = ifatoia(ifa); 829 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 830 pkt_dst.s_addr) 831 goto ours; 832 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 833 goto ours; 834 #ifdef BOOTP_COMPAT 835 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 836 goto ours; 837 #endif 838 } 839 } 840 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 841 struct in_multi *inm; 842 843 if (ip_mrouter != NULL) { 844 /* 845 * If we are acting as a multicast router, all 846 * incoming multicast packets are passed to the 847 * kernel-level multicast forwarding function. 848 * The packet is returned (relatively) intact; if 849 * ip_mforward() returns a non-zero value, the packet 850 * must be discarded, else it may be accepted below. 851 */ 852 if (ip_mforward != NULL && 853 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 854 ipstat.ips_cantforward++; 855 m_freem(m); 856 return; 857 } 858 859 /* 860 * The process-level routing daemon needs to receive 861 * all multicast IGMP packets, whether or not this 862 * host belongs to their destination groups. 863 */ 864 if (ip->ip_p == IPPROTO_IGMP) 865 goto ours; 866 ipstat.ips_forward++; 867 } 868 /* 869 * See if we belong to the destination multicast group on the 870 * arrival interface. 871 */ 872 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 873 if (inm == NULL) { 874 ipstat.ips_notmember++; 875 m_freem(m); 876 return; 877 } 878 goto ours; 879 } 880 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 881 goto ours; 882 if (ip->ip_dst.s_addr == INADDR_ANY) 883 goto ours; 884 885 /* 886 * FAITH(Firewall Aided Internet Translator) 887 */ 888 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 889 if (ip_keepfaith) { 890 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 891 goto ours; 892 } 893 m_freem(m); 894 return; 895 } 896 897 /* 898 * Not for us; forward if possible and desirable. 899 */ 900 if (!ipforwarding) { 901 ipstat.ips_cantforward++; 902 m_freem(m); 903 } else { 904 #ifdef IPSEC 905 /* 906 * Enforce inbound IPsec SPD. 907 */ 908 if (ipsec4_in_reject(m, NULL)) { 909 ipsecstat.in_polvio++; 910 goto bad; 911 } 912 #endif 913 #ifdef FAST_IPSEC 914 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 915 crit_enter(); 916 if (mtag != NULL) { 917 tdbi = (struct tdb_ident *)m_tag_data(mtag); 918 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 919 } else { 920 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 921 IP_FORWARDING, &error); 922 } 923 if (sp == NULL) { /* NB: can happen if error */ 924 crit_exit(); 925 /*XXX error stat???*/ 926 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 927 goto bad; 928 } 929 930 /* 931 * Check security policy against packet attributes. 932 */ 933 error = ipsec_in_reject(sp, m); 934 KEY_FREESP(&sp); 935 crit_exit(); 936 if (error) { 937 ipstat.ips_cantforward++; 938 goto bad; 939 } 940 #endif 941 ip_forward(m, using_srcrt, next_hop); 942 } 943 return; 944 945 ours: 946 947 /* 948 * IPSTEALTH: Process non-routing options only 949 * if the packet is destined for us. 950 */ 951 if (ipstealth && 952 hlen > sizeof(struct ip) && 953 ip_dooptions(m, 1, next_hop)) 954 return; 955 956 /* Count the packet in the ip address stats */ 957 if (ia != NULL) { 958 ia->ia_ifa.if_ipackets++; 959 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 960 } 961 962 /* 963 * If offset or IP_MF are set, must reassemble. 964 * Otherwise, nothing need be done. 965 * (We could look in the reassembly queue to see 966 * if the packet was previously fragmented, 967 * but it's not worth the time; just let them time out.) 968 */ 969 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 970 /* 971 * Attempt reassembly; if it succeeds, proceed. 972 * ip_reass() will return a different mbuf. 973 */ 974 m = ip_reass(m); 975 if (m == NULL) 976 return; 977 ip = mtod(m, struct ip *); 978 979 /* Get the header length of the reassembled packet */ 980 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 981 982 needredispatch = TRUE; 983 } else { 984 ip->ip_len -= hlen; 985 } 986 987 #ifdef IPSEC 988 /* 989 * enforce IPsec policy checking if we are seeing last header. 990 * note that we do not visit this with protocols with pcb layer 991 * code - like udp/tcp/raw ip. 992 */ 993 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 994 ipsec4_in_reject(m, NULL)) { 995 ipsecstat.in_polvio++; 996 goto bad; 997 } 998 #endif 999 #if FAST_IPSEC 1000 /* 1001 * enforce IPsec policy checking if we are seeing last header. 1002 * note that we do not visit this with protocols with pcb layer 1003 * code - like udp/tcp/raw ip. 1004 */ 1005 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 1006 /* 1007 * Check if the packet has already had IPsec processing 1008 * done. If so, then just pass it along. This tag gets 1009 * set during AH, ESP, etc. input handling, before the 1010 * packet is returned to the ip input queue for delivery. 1011 */ 1012 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 1013 crit_enter(); 1014 if (mtag != NULL) { 1015 tdbi = (struct tdb_ident *)m_tag_data(mtag); 1016 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 1017 } else { 1018 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 1019 IP_FORWARDING, &error); 1020 } 1021 if (sp != NULL) { 1022 /* 1023 * Check security policy against packet attributes. 1024 */ 1025 error = ipsec_in_reject(sp, m); 1026 KEY_FREESP(&sp); 1027 } else { 1028 /* XXX error stat??? */ 1029 error = EINVAL; 1030 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 1031 goto bad; 1032 } 1033 crit_exit(); 1034 if (error) 1035 goto bad; 1036 } 1037 #endif /* FAST_IPSEC */ 1038 1039 ipstat.ips_delivered++; 1040 if (needredispatch) { 1041 struct netmsg_packet *pmsg; 1042 lwkt_port_t port; 1043 1044 ip->ip_off = htons(ip->ip_off); 1045 ip->ip_len = htons(ip->ip_len); 1046 port = ip_mport_in(&m); 1047 if (port == NULL) 1048 return; 1049 1050 pmsg = &m->m_hdr.mh_netmsg; 1051 netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, 0, 1052 transport_processing_handler); 1053 pmsg->nm_packet = m; 1054 pmsg->nm_netmsg.nm_lmsg.u.ms_result = hlen; 1055 1056 ip = mtod(m, struct ip *); 1057 ip->ip_len = ntohs(ip->ip_len); 1058 ip->ip_off = ntohs(ip->ip_off); 1059 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg); 1060 } else { 1061 transport_processing_oncpu(m, hlen, ip); 1062 } 1063 return; 1064 1065 bad: 1066 m_freem(m); 1067 } 1068 1069 /* 1070 * Take incoming datagram fragment and try to reassemble it into 1071 * whole datagram. If a chain for reassembly of this datagram already 1072 * exists, then it is given as fp; otherwise have to make a chain. 1073 */ 1074 static struct mbuf * 1075 ip_reass(struct mbuf *m) 1076 { 1077 struct ip *ip = mtod(m, struct ip *); 1078 struct mbuf *p = NULL, *q, *nq; 1079 struct mbuf *n; 1080 struct ipq *fp = NULL; 1081 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 1082 int i, next; 1083 u_short sum; 1084 1085 /* If maxnipq is 0, never accept fragments. */ 1086 if (maxnipq == 0) { 1087 ipstat.ips_fragments++; 1088 ipstat.ips_fragdropped++; 1089 m_freem(m); 1090 return NULL; 1091 } 1092 1093 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 1094 /* 1095 * Look for queue of fragments of this datagram. 1096 */ 1097 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 1098 if (ip->ip_id == fp->ipq_id && 1099 ip->ip_src.s_addr == fp->ipq_src.s_addr && 1100 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 1101 ip->ip_p == fp->ipq_p) 1102 goto found; 1103 1104 fp = NULL; 1105 1106 /* 1107 * Enforce upper bound on number of fragmented packets 1108 * for which we attempt reassembly; 1109 * If maxnipq is -1, accept all fragments without limitation. 1110 */ 1111 if (nipq > maxnipq && maxnipq > 0) { 1112 /* 1113 * drop something from the tail of the current queue 1114 * before proceeding further 1115 */ 1116 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 1117 for (i = 0; i < IPREASS_NHASH; i++) { 1118 if (ipq[i].prev != &ipq[i]) { 1119 ipstat.ips_fragtimeout += 1120 ipq[i].prev->ipq_nfrags; 1121 ip_freef(ipq[i].prev); 1122 break; 1123 } 1124 } 1125 } else { 1126 ipstat.ips_fragtimeout += 1127 ipq[sum].prev->ipq_nfrags; 1128 ip_freef(ipq[sum].prev); 1129 } 1130 } 1131 found: 1132 /* 1133 * Adjust ip_len to not reflect header, 1134 * convert offset of this to bytes. 1135 */ 1136 ip->ip_len -= hlen; 1137 if (ip->ip_off & IP_MF) { 1138 /* 1139 * Make sure that fragments have a data length 1140 * that's a non-zero multiple of 8 bytes. 1141 */ 1142 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 1143 ipstat.ips_toosmall++; /* XXX */ 1144 m_freem(m); 1145 return NULL; 1146 } 1147 m->m_flags |= M_FRAG; 1148 } else 1149 m->m_flags &= ~M_FRAG; 1150 ip->ip_off <<= 3; 1151 1152 ipstat.ips_fragments++; 1153 m->m_pkthdr.header = ip; 1154 1155 /* 1156 * If the hardware has not done csum over this fragment 1157 * then csum_data is not valid at all. 1158 */ 1159 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) 1160 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) { 1161 m->m_pkthdr.csum_data = 0; 1162 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR); 1163 } 1164 1165 /* 1166 * Presence of header sizes in mbufs 1167 * would confuse code below. 1168 */ 1169 m->m_data += hlen; 1170 m->m_len -= hlen; 1171 1172 /* 1173 * If first fragment to arrive, create a reassembly queue. 1174 */ 1175 if (fp == NULL) { 1176 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1177 goto dropfrag; 1178 insque(fp, &ipq[sum]); 1179 nipq++; 1180 fp->ipq_nfrags = 1; 1181 fp->ipq_ttl = IPFRAGTTL; 1182 fp->ipq_p = ip->ip_p; 1183 fp->ipq_id = ip->ip_id; 1184 fp->ipq_src = ip->ip_src; 1185 fp->ipq_dst = ip->ip_dst; 1186 fp->ipq_frags = m; 1187 m->m_nextpkt = NULL; 1188 goto inserted; 1189 } else { 1190 fp->ipq_nfrags++; 1191 } 1192 1193 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1194 1195 /* 1196 * Find a segment which begins after this one does. 1197 */ 1198 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1199 if (GETIP(q)->ip_off > ip->ip_off) 1200 break; 1201 1202 /* 1203 * If there is a preceding segment, it may provide some of 1204 * our data already. If so, drop the data from the incoming 1205 * segment. If it provides all of our data, drop us, otherwise 1206 * stick new segment in the proper place. 1207 * 1208 * If some of the data is dropped from the the preceding 1209 * segment, then it's checksum is invalidated. 1210 */ 1211 if (p) { 1212 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1213 if (i > 0) { 1214 if (i >= ip->ip_len) 1215 goto dropfrag; 1216 m_adj(m, i); 1217 m->m_pkthdr.csum_flags = 0; 1218 ip->ip_off += i; 1219 ip->ip_len -= i; 1220 } 1221 m->m_nextpkt = p->m_nextpkt; 1222 p->m_nextpkt = m; 1223 } else { 1224 m->m_nextpkt = fp->ipq_frags; 1225 fp->ipq_frags = m; 1226 } 1227 1228 /* 1229 * While we overlap succeeding segments trim them or, 1230 * if they are completely covered, dequeue them. 1231 */ 1232 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1233 q = nq) { 1234 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1235 if (i < GETIP(q)->ip_len) { 1236 GETIP(q)->ip_len -= i; 1237 GETIP(q)->ip_off += i; 1238 m_adj(q, i); 1239 q->m_pkthdr.csum_flags = 0; 1240 break; 1241 } 1242 nq = q->m_nextpkt; 1243 m->m_nextpkt = nq; 1244 ipstat.ips_fragdropped++; 1245 fp->ipq_nfrags--; 1246 q->m_nextpkt = NULL; 1247 m_freem(q); 1248 } 1249 1250 inserted: 1251 /* 1252 * Check for complete reassembly and perform frag per packet 1253 * limiting. 1254 * 1255 * Frag limiting is performed here so that the nth frag has 1256 * a chance to complete the packet before we drop the packet. 1257 * As a result, n+1 frags are actually allowed per packet, but 1258 * only n will ever be stored. (n = maxfragsperpacket.) 1259 * 1260 */ 1261 next = 0; 1262 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1263 if (GETIP(q)->ip_off != next) { 1264 if (fp->ipq_nfrags > maxfragsperpacket) { 1265 ipstat.ips_fragdropped += fp->ipq_nfrags; 1266 ip_freef(fp); 1267 } 1268 return (NULL); 1269 } 1270 next += GETIP(q)->ip_len; 1271 } 1272 /* Make sure the last packet didn't have the IP_MF flag */ 1273 if (p->m_flags & M_FRAG) { 1274 if (fp->ipq_nfrags > maxfragsperpacket) { 1275 ipstat.ips_fragdropped += fp->ipq_nfrags; 1276 ip_freef(fp); 1277 } 1278 return (NULL); 1279 } 1280 1281 /* 1282 * Reassembly is complete. Make sure the packet is a sane size. 1283 */ 1284 q = fp->ipq_frags; 1285 ip = GETIP(q); 1286 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1287 ipstat.ips_toolong++; 1288 ipstat.ips_fragdropped += fp->ipq_nfrags; 1289 ip_freef(fp); 1290 return (NULL); 1291 } 1292 1293 /* 1294 * Concatenate fragments. 1295 */ 1296 m = q; 1297 n = m->m_next; 1298 m->m_next = NULL; 1299 m_cat(m, n); 1300 nq = q->m_nextpkt; 1301 q->m_nextpkt = NULL; 1302 for (q = nq; q != NULL; q = nq) { 1303 nq = q->m_nextpkt; 1304 q->m_nextpkt = NULL; 1305 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1306 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1307 m_cat(m, q); 1308 } 1309 1310 /* 1311 * Clean up the 1's complement checksum. Carry over 16 bits must 1312 * be added back. This assumes no more then 65535 packet fragments 1313 * were reassembled. A second carry can also occur (but not a third). 1314 */ 1315 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + 1316 (m->m_pkthdr.csum_data >> 16); 1317 if (m->m_pkthdr.csum_data > 0xFFFF) 1318 m->m_pkthdr.csum_data -= 0xFFFF; 1319 1320 /* 1321 * Create header for new ip packet by 1322 * modifying header of first packet; 1323 * dequeue and discard fragment reassembly header. 1324 * Make header visible. 1325 */ 1326 ip->ip_len = next; 1327 ip->ip_src = fp->ipq_src; 1328 ip->ip_dst = fp->ipq_dst; 1329 remque(fp); 1330 nipq--; 1331 mpipe_free(&ipq_mpipe, fp); 1332 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1333 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1334 /* some debugging cruft by sklower, below, will go away soon */ 1335 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1336 int plen = 0; 1337 1338 for (n = m; n; n = n->m_next) 1339 plen += n->m_len; 1340 m->m_pkthdr.len = plen; 1341 } 1342 1343 ipstat.ips_reassembled++; 1344 return (m); 1345 1346 dropfrag: 1347 ipstat.ips_fragdropped++; 1348 if (fp != NULL) 1349 fp->ipq_nfrags--; 1350 m_freem(m); 1351 return (NULL); 1352 1353 #undef GETIP 1354 } 1355 1356 /* 1357 * Free a fragment reassembly header and all 1358 * associated datagrams. 1359 */ 1360 static void 1361 ip_freef(struct ipq *fp) 1362 { 1363 struct mbuf *q; 1364 1365 while (fp->ipq_frags) { 1366 q = fp->ipq_frags; 1367 fp->ipq_frags = q->m_nextpkt; 1368 q->m_nextpkt = NULL; 1369 m_freem(q); 1370 } 1371 remque(fp); 1372 mpipe_free(&ipq_mpipe, fp); 1373 nipq--; 1374 } 1375 1376 /* 1377 * IP timer processing; 1378 * if a timer expires on a reassembly 1379 * queue, discard it. 1380 */ 1381 void 1382 ip_slowtimo(void) 1383 { 1384 struct ipq *fp; 1385 int i; 1386 1387 crit_enter(); 1388 for (i = 0; i < IPREASS_NHASH; i++) { 1389 fp = ipq[i].next; 1390 if (fp == NULL) 1391 continue; 1392 while (fp != &ipq[i]) { 1393 --fp->ipq_ttl; 1394 fp = fp->next; 1395 if (fp->prev->ipq_ttl == 0) { 1396 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1397 ip_freef(fp->prev); 1398 } 1399 } 1400 } 1401 /* 1402 * If we are over the maximum number of fragments 1403 * (due to the limit being lowered), drain off 1404 * enough to get down to the new limit. 1405 */ 1406 if (maxnipq >= 0 && nipq > maxnipq) { 1407 for (i = 0; i < IPREASS_NHASH; i++) { 1408 while (nipq > maxnipq && 1409 (ipq[i].next != &ipq[i])) { 1410 ipstat.ips_fragdropped += 1411 ipq[i].next->ipq_nfrags; 1412 ip_freef(ipq[i].next); 1413 } 1414 } 1415 } 1416 ipflow_slowtimo(); 1417 crit_exit(); 1418 } 1419 1420 /* 1421 * Drain off all datagram fragments. 1422 */ 1423 void 1424 ip_drain(void) 1425 { 1426 int i; 1427 1428 for (i = 0; i < IPREASS_NHASH; i++) { 1429 while (ipq[i].next != &ipq[i]) { 1430 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1431 ip_freef(ipq[i].next); 1432 } 1433 } 1434 in_rtqdrain(); 1435 } 1436 1437 /* 1438 * Do option processing on a datagram, 1439 * possibly discarding it if bad options are encountered, 1440 * or forwarding it if source-routed. 1441 * The pass argument is used when operating in the IPSTEALTH 1442 * mode to tell what options to process: 1443 * [LS]SRR (pass 0) or the others (pass 1). 1444 * The reason for as many as two passes is that when doing IPSTEALTH, 1445 * non-routing options should be processed only if the packet is for us. 1446 * Returns 1 if packet has been forwarded/freed, 1447 * 0 if the packet should be processed further. 1448 */ 1449 static int 1450 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1451 { 1452 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1453 struct ip *ip = mtod(m, struct ip *); 1454 u_char *cp; 1455 struct in_ifaddr *ia; 1456 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1457 boolean_t forward = FALSE; 1458 struct in_addr *sin, dst; 1459 n_time ntime; 1460 1461 dst = ip->ip_dst; 1462 cp = (u_char *)(ip + 1); 1463 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1464 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1465 opt = cp[IPOPT_OPTVAL]; 1466 if (opt == IPOPT_EOL) 1467 break; 1468 if (opt == IPOPT_NOP) 1469 optlen = 1; 1470 else { 1471 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1472 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1473 goto bad; 1474 } 1475 optlen = cp[IPOPT_OLEN]; 1476 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1477 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1478 goto bad; 1479 } 1480 } 1481 switch (opt) { 1482 1483 default: 1484 break; 1485 1486 /* 1487 * Source routing with record. 1488 * Find interface with current destination address. 1489 * If none on this machine then drop if strictly routed, 1490 * or do nothing if loosely routed. 1491 * Record interface address and bring up next address 1492 * component. If strictly routed make sure next 1493 * address is on directly accessible net. 1494 */ 1495 case IPOPT_LSRR: 1496 case IPOPT_SSRR: 1497 if (ipstealth && pass > 0) 1498 break; 1499 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1500 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1501 goto bad; 1502 } 1503 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1504 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1505 goto bad; 1506 } 1507 ipaddr.sin_addr = ip->ip_dst; 1508 ia = (struct in_ifaddr *) 1509 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1510 if (ia == NULL) { 1511 if (opt == IPOPT_SSRR) { 1512 type = ICMP_UNREACH; 1513 code = ICMP_UNREACH_SRCFAIL; 1514 goto bad; 1515 } 1516 if (!ip_dosourceroute) 1517 goto nosourcerouting; 1518 /* 1519 * Loose routing, and not at next destination 1520 * yet; nothing to do except forward. 1521 */ 1522 break; 1523 } 1524 off--; /* 0 origin */ 1525 if (off > optlen - (int)sizeof(struct in_addr)) { 1526 /* 1527 * End of source route. Should be for us. 1528 */ 1529 if (!ip_acceptsourceroute) 1530 goto nosourcerouting; 1531 save_rte(m, cp, ip->ip_src); 1532 break; 1533 } 1534 if (ipstealth) 1535 goto dropit; 1536 if (!ip_dosourceroute) { 1537 if (ipforwarding) { 1538 char buf[sizeof "aaa.bbb.ccc.ddd"]; 1539 1540 /* 1541 * Acting as a router, so generate ICMP 1542 */ 1543 nosourcerouting: 1544 strcpy(buf, inet_ntoa(ip->ip_dst)); 1545 log(LOG_WARNING, 1546 "attempted source route from %s to %s\n", 1547 inet_ntoa(ip->ip_src), buf); 1548 type = ICMP_UNREACH; 1549 code = ICMP_UNREACH_SRCFAIL; 1550 goto bad; 1551 } else { 1552 /* 1553 * Not acting as a router, 1554 * so silently drop. 1555 */ 1556 dropit: 1557 ipstat.ips_cantforward++; 1558 m_freem(m); 1559 return (1); 1560 } 1561 } 1562 1563 /* 1564 * locate outgoing interface 1565 */ 1566 memcpy(&ipaddr.sin_addr, cp + off, 1567 sizeof ipaddr.sin_addr); 1568 1569 if (opt == IPOPT_SSRR) { 1570 #define INA struct in_ifaddr * 1571 #define SA struct sockaddr * 1572 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1573 == NULL) 1574 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1575 } else 1576 ia = ip_rtaddr(ipaddr.sin_addr, 1577 &ipforward_rt[mycpuid]); 1578 if (ia == NULL) { 1579 type = ICMP_UNREACH; 1580 code = ICMP_UNREACH_SRCFAIL; 1581 goto bad; 1582 } 1583 ip->ip_dst = ipaddr.sin_addr; 1584 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1585 sizeof(struct in_addr)); 1586 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1587 /* 1588 * Let ip_intr's mcast routing check handle mcast pkts 1589 */ 1590 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1591 break; 1592 1593 case IPOPT_RR: 1594 if (ipstealth && pass == 0) 1595 break; 1596 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1597 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1598 goto bad; 1599 } 1600 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1601 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1602 goto bad; 1603 } 1604 /* 1605 * If no space remains, ignore. 1606 */ 1607 off--; /* 0 origin */ 1608 if (off > optlen - (int)sizeof(struct in_addr)) 1609 break; 1610 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1611 sizeof ipaddr.sin_addr); 1612 /* 1613 * locate outgoing interface; if we're the destination, 1614 * use the incoming interface (should be same). 1615 */ 1616 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1617 (ia = ip_rtaddr(ipaddr.sin_addr, 1618 &ipforward_rt[mycpuid])) 1619 == NULL) { 1620 type = ICMP_UNREACH; 1621 code = ICMP_UNREACH_HOST; 1622 goto bad; 1623 } 1624 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1625 sizeof(struct in_addr)); 1626 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1627 break; 1628 1629 case IPOPT_TS: 1630 if (ipstealth && pass == 0) 1631 break; 1632 code = cp - (u_char *)ip; 1633 if (optlen < 4 || optlen > 40) { 1634 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1635 goto bad; 1636 } 1637 if ((off = cp[IPOPT_OFFSET]) < 5) { 1638 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1639 goto bad; 1640 } 1641 if (off > optlen - (int)sizeof(int32_t)) { 1642 cp[IPOPT_OFFSET + 1] += (1 << 4); 1643 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1644 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1645 goto bad; 1646 } 1647 break; 1648 } 1649 off--; /* 0 origin */ 1650 sin = (struct in_addr *)(cp + off); 1651 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1652 1653 case IPOPT_TS_TSONLY: 1654 break; 1655 1656 case IPOPT_TS_TSANDADDR: 1657 if (off + sizeof(n_time) + 1658 sizeof(struct in_addr) > optlen) { 1659 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1660 goto bad; 1661 } 1662 ipaddr.sin_addr = dst; 1663 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1664 m->m_pkthdr.rcvif); 1665 if (ia == NULL) 1666 continue; 1667 memcpy(sin, &IA_SIN(ia)->sin_addr, 1668 sizeof(struct in_addr)); 1669 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1670 off += sizeof(struct in_addr); 1671 break; 1672 1673 case IPOPT_TS_PRESPEC: 1674 if (off + sizeof(n_time) + 1675 sizeof(struct in_addr) > optlen) { 1676 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1677 goto bad; 1678 } 1679 memcpy(&ipaddr.sin_addr, sin, 1680 sizeof(struct in_addr)); 1681 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1682 continue; 1683 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1684 off += sizeof(struct in_addr); 1685 break; 1686 1687 default: 1688 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1689 goto bad; 1690 } 1691 ntime = iptime(); 1692 memcpy(cp + off, &ntime, sizeof(n_time)); 1693 cp[IPOPT_OFFSET] += sizeof(n_time); 1694 } 1695 } 1696 if (forward && ipforwarding) { 1697 ip_forward(m, TRUE, next_hop); 1698 return (1); 1699 } 1700 return (0); 1701 bad: 1702 icmp_error(m, type, code, 0, 0); 1703 ipstat.ips_badoptions++; 1704 return (1); 1705 } 1706 1707 /* 1708 * Given address of next destination (final or next hop), 1709 * return internet address info of interface to be used to get there. 1710 */ 1711 struct in_ifaddr * 1712 ip_rtaddr(struct in_addr dst, struct route *ro) 1713 { 1714 struct sockaddr_in *sin; 1715 1716 sin = (struct sockaddr_in *)&ro->ro_dst; 1717 1718 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1719 if (ro->ro_rt != NULL) { 1720 RTFREE(ro->ro_rt); 1721 ro->ro_rt = NULL; 1722 } 1723 sin->sin_family = AF_INET; 1724 sin->sin_len = sizeof *sin; 1725 sin->sin_addr = dst; 1726 rtalloc_ign(ro, RTF_PRCLONING); 1727 } 1728 1729 if (ro->ro_rt == NULL) 1730 return (NULL); 1731 1732 return (ifatoia(ro->ro_rt->rt_ifa)); 1733 } 1734 1735 /* 1736 * Save incoming source route for use in replies, 1737 * to be picked up later by ip_srcroute if the receiver is interested. 1738 */ 1739 static void 1740 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1741 { 1742 struct m_tag *mtag; 1743 struct ip_srcrt_opt *opt; 1744 unsigned olen; 1745 1746 mtag = m_tag_get(PACKET_TAG_IPSRCRT, sizeof(*opt), MB_DONTWAIT); 1747 if (mtag == NULL) 1748 return; 1749 opt = m_tag_data(mtag); 1750 1751 olen = option[IPOPT_OLEN]; 1752 #ifdef DIAGNOSTIC 1753 if (ipprintfs) 1754 kprintf("save_rte: olen %d\n", olen); 1755 #endif 1756 if (olen > sizeof(opt->ip_srcrt) - (1 + sizeof(dst))) { 1757 m_tag_free(mtag); 1758 return; 1759 } 1760 bcopy(option, opt->ip_srcrt.srcopt, olen); 1761 opt->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1762 opt->ip_srcrt.dst = dst; 1763 m_tag_prepend(m, mtag); 1764 } 1765 1766 /* 1767 * Retrieve incoming source route for use in replies, 1768 * in the same form used by setsockopt. 1769 * The first hop is placed before the options, will be removed later. 1770 */ 1771 struct mbuf * 1772 ip_srcroute(struct mbuf *m0) 1773 { 1774 struct in_addr *p, *q; 1775 struct mbuf *m; 1776 struct m_tag *mtag; 1777 struct ip_srcrt_opt *opt; 1778 1779 if (m0 == NULL) 1780 return NULL; 1781 1782 mtag = m_tag_find(m0, PACKET_TAG_IPSRCRT, NULL); 1783 if (mtag == NULL) 1784 return NULL; 1785 opt = m_tag_data(mtag); 1786 1787 if (opt->ip_nhops == 0) 1788 return (NULL); 1789 m = m_get(MB_DONTWAIT, MT_HEADER); 1790 if (m == NULL) 1791 return (NULL); 1792 1793 #define OPTSIZ (sizeof(opt->ip_srcrt.nop) + sizeof(opt->ip_srcrt.srcopt)) 1794 1795 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1796 m->m_len = opt->ip_nhops * sizeof(struct in_addr) + 1797 sizeof(struct in_addr) + OPTSIZ; 1798 #ifdef DIAGNOSTIC 1799 if (ipprintfs) { 1800 kprintf("ip_srcroute: nhops %d mlen %d", 1801 opt->ip_nhops, m->m_len); 1802 } 1803 #endif 1804 1805 /* 1806 * First save first hop for return route 1807 */ 1808 p = &opt->ip_srcrt.route[opt->ip_nhops - 1]; 1809 *(mtod(m, struct in_addr *)) = *p--; 1810 #ifdef DIAGNOSTIC 1811 if (ipprintfs) 1812 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1813 #endif 1814 1815 /* 1816 * Copy option fields and padding (nop) to mbuf. 1817 */ 1818 opt->ip_srcrt.nop = IPOPT_NOP; 1819 opt->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1820 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &opt->ip_srcrt.nop, 1821 OPTSIZ); 1822 q = (struct in_addr *)(mtod(m, caddr_t) + 1823 sizeof(struct in_addr) + OPTSIZ); 1824 #undef OPTSIZ 1825 /* 1826 * Record return path as an IP source route, 1827 * reversing the path (pointers are now aligned). 1828 */ 1829 while (p >= opt->ip_srcrt.route) { 1830 #ifdef DIAGNOSTIC 1831 if (ipprintfs) 1832 kprintf(" %x", ntohl(q->s_addr)); 1833 #endif 1834 *q++ = *p--; 1835 } 1836 /* 1837 * Last hop goes to final destination. 1838 */ 1839 *q = opt->ip_srcrt.dst; 1840 m_tag_delete(m0, mtag); 1841 #ifdef DIAGNOSTIC 1842 if (ipprintfs) 1843 kprintf(" %x\n", ntohl(q->s_addr)); 1844 #endif 1845 return (m); 1846 } 1847 1848 /* 1849 * Strip out IP options. 1850 */ 1851 void 1852 ip_stripoptions(struct mbuf *m) 1853 { 1854 int datalen; 1855 struct ip *ip = mtod(m, struct ip *); 1856 caddr_t opts; 1857 int optlen; 1858 1859 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1860 opts = (caddr_t)(ip + 1); 1861 datalen = m->m_len - (sizeof(struct ip) + optlen); 1862 bcopy(opts + optlen, opts, datalen); 1863 m->m_len -= optlen; 1864 if (m->m_flags & M_PKTHDR) 1865 m->m_pkthdr.len -= optlen; 1866 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1867 } 1868 1869 u_char inetctlerrmap[PRC_NCMDS] = { 1870 0, 0, 0, 0, 1871 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1872 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1873 EMSGSIZE, EHOSTUNREACH, 0, 0, 1874 0, 0, 0, 0, 1875 ENOPROTOOPT, ECONNREFUSED 1876 }; 1877 1878 /* 1879 * Forward a packet. If some error occurs return the sender 1880 * an icmp packet. Note we can't always generate a meaningful 1881 * icmp message because icmp doesn't have a large enough repertoire 1882 * of codes and types. 1883 * 1884 * If not forwarding, just drop the packet. This could be confusing 1885 * if ipforwarding was zero but some routing protocol was advancing 1886 * us as a gateway to somewhere. However, we must let the routing 1887 * protocol deal with that. 1888 * 1889 * The using_srcrt parameter indicates whether the packet is being forwarded 1890 * via a source route. 1891 */ 1892 void 1893 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop) 1894 { 1895 struct ip *ip = mtod(m, struct ip *); 1896 struct sockaddr_in *ipforward_rtaddr; 1897 struct rtentry *rt; 1898 int error, type = 0, code = 0, destmtu = 0; 1899 struct mbuf *mcopy; 1900 n_long dest; 1901 struct in_addr pkt_dst; 1902 struct route *cache_rt = &ipforward_rt[mycpuid]; 1903 1904 dest = INADDR_ANY; 1905 /* 1906 * Cache the destination address of the packet; this may be 1907 * changed by use of 'ipfw fwd'. 1908 */ 1909 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 1910 1911 #ifdef DIAGNOSTIC 1912 if (ipprintfs) 1913 kprintf("forward: src %x dst %x ttl %x\n", 1914 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1915 #endif 1916 1917 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1918 ipstat.ips_cantforward++; 1919 m_freem(m); 1920 return; 1921 } 1922 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1923 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1924 return; 1925 } 1926 1927 ipforward_rtaddr = (struct sockaddr_in *) &cache_rt->ro_dst; 1928 if (cache_rt->ro_rt == NULL || 1929 ipforward_rtaddr->sin_addr.s_addr != pkt_dst.s_addr) { 1930 if (cache_rt->ro_rt != NULL) { 1931 RTFREE(cache_rt->ro_rt); 1932 cache_rt->ro_rt = NULL; 1933 } 1934 ipforward_rtaddr->sin_family = AF_INET; 1935 ipforward_rtaddr->sin_len = sizeof(struct sockaddr_in); 1936 ipforward_rtaddr->sin_addr = pkt_dst; 1937 rtalloc_ign(cache_rt, RTF_PRCLONING); 1938 if (cache_rt->ro_rt == NULL) { 1939 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1940 return; 1941 } 1942 } 1943 rt = cache_rt->ro_rt; 1944 1945 /* 1946 * Save the IP header and at most 8 bytes of the payload, 1947 * in case we need to generate an ICMP message to the src. 1948 * 1949 * XXX this can be optimized a lot by saving the data in a local 1950 * buffer on the stack (72 bytes at most), and only allocating the 1951 * mbuf if really necessary. The vast majority of the packets 1952 * are forwarded without having to send an ICMP back (either 1953 * because unnecessary, or because rate limited), so we are 1954 * really we are wasting a lot of work here. 1955 * 1956 * We don't use m_copy() because it might return a reference 1957 * to a shared cluster. Both this function and ip_output() 1958 * assume exclusive access to the IP header in `m', so any 1959 * data in a cluster may change before we reach icmp_error(). 1960 */ 1961 MGETHDR(mcopy, MB_DONTWAIT, m->m_type); 1962 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) { 1963 /* 1964 * It's probably ok if the pkthdr dup fails (because 1965 * the deep copy of the tag chain failed), but for now 1966 * be conservative and just discard the copy since 1967 * code below may some day want the tags. 1968 */ 1969 m_free(mcopy); 1970 mcopy = NULL; 1971 } 1972 if (mcopy != NULL) { 1973 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1974 (int)ip->ip_len); 1975 mcopy->m_pkthdr.len = mcopy->m_len; 1976 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1977 } 1978 1979 if (!ipstealth) 1980 ip->ip_ttl -= IPTTLDEC; 1981 1982 /* 1983 * If forwarding packet using same interface that it came in on, 1984 * perhaps should send a redirect to sender to shortcut a hop. 1985 * Only send redirect if source is sending directly to us, 1986 * and if packet was not source routed (or has any options). 1987 * Also, don't send redirect if forwarding using a default route 1988 * or a route modified by a redirect. 1989 */ 1990 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1991 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1992 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1993 ipsendredirects && !using_srcrt && next_hop == NULL) { 1994 u_long src = ntohl(ip->ip_src.s_addr); 1995 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa; 1996 1997 if (rt_ifa != NULL && 1998 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) { 1999 if (rt->rt_flags & RTF_GATEWAY) 2000 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 2001 else 2002 dest = pkt_dst.s_addr; 2003 /* 2004 * Router requirements says to only send 2005 * host redirects. 2006 */ 2007 type = ICMP_REDIRECT; 2008 code = ICMP_REDIRECT_HOST; 2009 #ifdef DIAGNOSTIC 2010 if (ipprintfs) 2011 kprintf("redirect (%d) to %x\n", code, dest); 2012 #endif 2013 } 2014 } 2015 2016 error = ip_output(m, NULL, cache_rt, IP_FORWARDING, NULL, NULL); 2017 if (error == 0) { 2018 ipstat.ips_forward++; 2019 if (type == 0) { 2020 if (mcopy) { 2021 ipflow_create(cache_rt, mcopy); 2022 m_freem(mcopy); 2023 } 2024 return; /* most common case */ 2025 } else { 2026 ipstat.ips_redirectsent++; 2027 } 2028 } else { 2029 ipstat.ips_cantforward++; 2030 } 2031 2032 if (mcopy == NULL) 2033 return; 2034 2035 /* 2036 * Send ICMP message. 2037 */ 2038 2039 switch (error) { 2040 2041 case 0: /* forwarded, but need redirect */ 2042 /* type, code set above */ 2043 break; 2044 2045 case ENETUNREACH: /* shouldn't happen, checked above */ 2046 case EHOSTUNREACH: 2047 case ENETDOWN: 2048 case EHOSTDOWN: 2049 default: 2050 type = ICMP_UNREACH; 2051 code = ICMP_UNREACH_HOST; 2052 break; 2053 2054 case EMSGSIZE: 2055 type = ICMP_UNREACH; 2056 code = ICMP_UNREACH_NEEDFRAG; 2057 #ifdef IPSEC 2058 /* 2059 * If the packet is routed over IPsec tunnel, tell the 2060 * originator the tunnel MTU. 2061 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2062 * XXX quickhack!!! 2063 */ 2064 if (cache_rt->ro_rt != NULL) { 2065 struct secpolicy *sp = NULL; 2066 int ipsecerror; 2067 int ipsechdr; 2068 struct route *ro; 2069 2070 sp = ipsec4_getpolicybyaddr(mcopy, 2071 IPSEC_DIR_OUTBOUND, 2072 IP_FORWARDING, 2073 &ipsecerror); 2074 2075 if (sp == NULL) 2076 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2077 else { 2078 /* count IPsec header size */ 2079 ipsechdr = ipsec4_hdrsiz(mcopy, 2080 IPSEC_DIR_OUTBOUND, 2081 NULL); 2082 2083 /* 2084 * find the correct route for outer IPv4 2085 * header, compute tunnel MTU. 2086 * 2087 */ 2088 if (sp->req != NULL && sp->req->sav != NULL && 2089 sp->req->sav->sah != NULL) { 2090 ro = &sp->req->sav->sah->sa_route; 2091 if (ro->ro_rt != NULL && 2092 ro->ro_rt->rt_ifp != NULL) { 2093 destmtu = 2094 ro->ro_rt->rt_ifp->if_mtu; 2095 destmtu -= ipsechdr; 2096 } 2097 } 2098 2099 key_freesp(sp); 2100 } 2101 } 2102 #elif FAST_IPSEC 2103 /* 2104 * If the packet is routed over IPsec tunnel, tell the 2105 * originator the tunnel MTU. 2106 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2107 * XXX quickhack!!! 2108 */ 2109 if (cache_rt->ro_rt != NULL) { 2110 struct secpolicy *sp = NULL; 2111 int ipsecerror; 2112 int ipsechdr; 2113 struct route *ro; 2114 2115 sp = ipsec_getpolicybyaddr(mcopy, 2116 IPSEC_DIR_OUTBOUND, 2117 IP_FORWARDING, 2118 &ipsecerror); 2119 2120 if (sp == NULL) 2121 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2122 else { 2123 /* count IPsec header size */ 2124 ipsechdr = ipsec4_hdrsiz(mcopy, 2125 IPSEC_DIR_OUTBOUND, 2126 NULL); 2127 2128 /* 2129 * find the correct route for outer IPv4 2130 * header, compute tunnel MTU. 2131 */ 2132 2133 if (sp->req != NULL && 2134 sp->req->sav != NULL && 2135 sp->req->sav->sah != NULL) { 2136 ro = &sp->req->sav->sah->sa_route; 2137 if (ro->ro_rt != NULL && 2138 ro->ro_rt->rt_ifp != NULL) { 2139 destmtu = 2140 ro->ro_rt->rt_ifp->if_mtu; 2141 destmtu -= ipsechdr; 2142 } 2143 } 2144 2145 KEY_FREESP(&sp); 2146 } 2147 } 2148 #else /* !IPSEC && !FAST_IPSEC */ 2149 if (cache_rt->ro_rt != NULL) 2150 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu; 2151 #endif /*IPSEC*/ 2152 ipstat.ips_cantfrag++; 2153 break; 2154 2155 case ENOBUFS: 2156 /* 2157 * A router should not generate ICMP_SOURCEQUENCH as 2158 * required in RFC1812 Requirements for IP Version 4 Routers. 2159 * Source quench could be a big problem under DoS attacks, 2160 * or if the underlying interface is rate-limited. 2161 * Those who need source quench packets may re-enable them 2162 * via the net.inet.ip.sendsourcequench sysctl. 2163 */ 2164 if (!ip_sendsourcequench) { 2165 m_freem(mcopy); 2166 return; 2167 } else { 2168 type = ICMP_SOURCEQUENCH; 2169 code = 0; 2170 } 2171 break; 2172 2173 case EACCES: /* ipfw denied packet */ 2174 m_freem(mcopy); 2175 return; 2176 } 2177 icmp_error(mcopy, type, code, dest, destmtu); 2178 } 2179 2180 void 2181 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2182 struct mbuf *m) 2183 { 2184 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2185 struct timeval tv; 2186 2187 microtime(&tv); 2188 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2189 SCM_TIMESTAMP, SOL_SOCKET); 2190 if (*mp) 2191 mp = &(*mp)->m_next; 2192 } 2193 if (inp->inp_flags & INP_RECVDSTADDR) { 2194 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2195 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2196 if (*mp) 2197 mp = &(*mp)->m_next; 2198 } 2199 if (inp->inp_flags & INP_RECVTTL) { 2200 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2201 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2202 if (*mp) 2203 mp = &(*mp)->m_next; 2204 } 2205 #ifdef notyet 2206 /* XXX 2207 * Moving these out of udp_input() made them even more broken 2208 * than they already were. 2209 */ 2210 /* options were tossed already */ 2211 if (inp->inp_flags & INP_RECVOPTS) { 2212 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2213 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2214 if (*mp) 2215 mp = &(*mp)->m_next; 2216 } 2217 /* ip_srcroute doesn't do what we want here, need to fix */ 2218 if (inp->inp_flags & INP_RECVRETOPTS) { 2219 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 2220 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2221 if (*mp) 2222 mp = &(*mp)->m_next; 2223 } 2224 #endif 2225 if (inp->inp_flags & INP_RECVIF) { 2226 struct ifnet *ifp; 2227 struct sdlbuf { 2228 struct sockaddr_dl sdl; 2229 u_char pad[32]; 2230 } sdlbuf; 2231 struct sockaddr_dl *sdp; 2232 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2233 2234 if (((ifp = m->m_pkthdr.rcvif)) && 2235 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2236 sdp = IF_LLSOCKADDR(ifp); 2237 /* 2238 * Change our mind and don't try copy. 2239 */ 2240 if ((sdp->sdl_family != AF_LINK) || 2241 (sdp->sdl_len > sizeof(sdlbuf))) { 2242 goto makedummy; 2243 } 2244 bcopy(sdp, sdl2, sdp->sdl_len); 2245 } else { 2246 makedummy: 2247 sdl2->sdl_len = 2248 offsetof(struct sockaddr_dl, sdl_data[0]); 2249 sdl2->sdl_family = AF_LINK; 2250 sdl2->sdl_index = 0; 2251 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2252 } 2253 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2254 IP_RECVIF, IPPROTO_IP); 2255 if (*mp) 2256 mp = &(*mp)->m_next; 2257 } 2258 } 2259 2260 /* 2261 * XXX these routines are called from the upper part of the kernel. 2262 * 2263 * They could also be moved to ip_mroute.c, since all the RSVP 2264 * handling is done there already. 2265 */ 2266 int 2267 ip_rsvp_init(struct socket *so) 2268 { 2269 if (so->so_type != SOCK_RAW || 2270 so->so_proto->pr_protocol != IPPROTO_RSVP) 2271 return EOPNOTSUPP; 2272 2273 if (ip_rsvpd != NULL) 2274 return EADDRINUSE; 2275 2276 ip_rsvpd = so; 2277 /* 2278 * This may seem silly, but we need to be sure we don't over-increment 2279 * the RSVP counter, in case something slips up. 2280 */ 2281 if (!ip_rsvp_on) { 2282 ip_rsvp_on = 1; 2283 rsvp_on++; 2284 } 2285 2286 return 0; 2287 } 2288 2289 int 2290 ip_rsvp_done(void) 2291 { 2292 ip_rsvpd = NULL; 2293 /* 2294 * This may seem silly, but we need to be sure we don't over-decrement 2295 * the RSVP counter, in case something slips up. 2296 */ 2297 if (ip_rsvp_on) { 2298 ip_rsvp_on = 0; 2299 rsvp_on--; 2300 } 2301 return 0; 2302 } 2303 2304 void 2305 rsvp_input(struct mbuf *m, ...) /* XXX must fixup manually */ 2306 { 2307 int off, proto; 2308 __va_list ap; 2309 2310 __va_start(ap, m); 2311 off = __va_arg(ap, int); 2312 proto = __va_arg(ap, int); 2313 __va_end(ap); 2314 2315 if (rsvp_input_p) { /* call the real one if loaded */ 2316 rsvp_input_p(m, off, proto); 2317 return; 2318 } 2319 2320 /* Can still get packets with rsvp_on = 0 if there is a local member 2321 * of the group to which the RSVP packet is addressed. But in this 2322 * case we want to throw the packet away. 2323 */ 2324 2325 if (!rsvp_on) { 2326 m_freem(m); 2327 return; 2328 } 2329 2330 if (ip_rsvpd != NULL) { 2331 rip_input(m, off, proto); 2332 return; 2333 } 2334 /* Drop the packet */ 2335 m_freem(m); 2336 } 2337