1 /* 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 34 * $FreeBSD: src/sys/netinet/ip_input.c,v 1.130.2.52 2003/03/07 07:01:28 silby Exp $ 35 * $DragonFly: src/sys/netinet/ip_input.c,v 1.30 2004/06/04 03:57:41 dillon Exp $ 36 */ 37 38 #define _IP_VHL 39 40 #include "opt_bootp.h" 41 #include "opt_ipfw.h" 42 #include "opt_ipdn.h" 43 #include "opt_ipdivert.h" 44 #include "opt_ipfilter.h" 45 #include "opt_ipstealth.h" 46 #include "opt_ipsec.h" 47 #include "opt_pfil_hooks.h" 48 #include "opt_random_ip_id.h" 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/mbuf.h> 53 #include <sys/malloc.h> 54 #include <sys/mpipe.h> 55 #include <sys/domain.h> 56 #include <sys/protosw.h> 57 #include <sys/socket.h> 58 #include <sys/time.h> 59 #include <sys/globaldata.h> 60 #include <sys/thread.h> 61 #include <sys/kernel.h> 62 #include <sys/syslog.h> 63 #include <sys/sysctl.h> 64 #include <sys/in_cksum.h> 65 66 #include <sys/thread2.h> 67 #include <sys/msgport2.h> 68 69 #include <machine/stdarg.h> 70 71 #include <net/if.h> 72 #include <net/if_types.h> 73 #include <net/if_var.h> 74 #include <net/if_dl.h> 75 #ifdef PFIL_HOOKS 76 #include <net/pfil.h> 77 #endif 78 #include <net/route.h> 79 #include <net/netisr.h> 80 #include <net/intrq.h> 81 82 #include <netinet/in.h> 83 #include <netinet/in_systm.h> 84 #include <netinet/in_var.h> 85 #include <netinet/ip.h> 86 #include <netinet/in_pcb.h> 87 #include <netinet/ip_var.h> 88 #include <netinet/ip_icmp.h> 89 90 #include <netinet/ipprotosw.h> 91 92 #include <sys/socketvar.h> 93 94 #include <net/ipfw/ip_fw.h> 95 #include <net/dummynet/ip_dummynet.h> 96 97 #ifdef IPSEC 98 #include <netinet6/ipsec.h> 99 #include <netproto/key/key.h> 100 #endif 101 102 #ifdef FAST_IPSEC 103 #include <netipsec/ipsec.h> 104 #include <netipsec/key.h> 105 #endif 106 107 int rsvp_on = 0; 108 static int ip_rsvp_on; 109 struct socket *ip_rsvpd; 110 111 int ipforwarding = 0; 112 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 113 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 114 115 static int ipsendredirects = 1; /* XXX */ 116 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 117 &ipsendredirects, 0, "Enable sending IP redirects"); 118 119 int ip_defttl = IPDEFTTL; 120 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 121 &ip_defttl, 0, "Maximum TTL on IP packets"); 122 123 static int ip_dosourceroute = 0; 124 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 125 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 126 127 static int ip_acceptsourceroute = 0; 128 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 129 CTLFLAG_RW, &ip_acceptsourceroute, 0, 130 "Enable accepting source routed IP packets"); 131 132 static int ip_keepfaith = 0; 133 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 134 &ip_keepfaith, 0, 135 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 136 137 static int nipq = 0; /* total # of reass queues */ 138 static int maxnipq; 139 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 140 &maxnipq, 0, 141 "Maximum number of IPv4 fragment reassembly queue entries"); 142 143 static int maxfragsperpacket; 144 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 145 &maxfragsperpacket, 0, 146 "Maximum number of IPv4 fragments allowed per packet"); 147 148 static int ip_sendsourcequench = 0; 149 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 150 &ip_sendsourcequench, 0, 151 "Enable the transmission of source quench packets"); 152 153 /* 154 * XXX - Setting ip_checkinterface mostly implements the receive side of 155 * the Strong ES model described in RFC 1122, but since the routing table 156 * and transmit implementation do not implement the Strong ES model, 157 * setting this to 1 results in an odd hybrid. 158 * 159 * XXX - ip_checkinterface currently must be disabled if you use ipnat 160 * to translate the destination address to another local interface. 161 * 162 * XXX - ip_checkinterface must be disabled if you add IP aliases 163 * to the loopback interface instead of the interface where the 164 * packets for those addresses are received. 165 */ 166 static int ip_checkinterface = 0; 167 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 168 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 169 170 #ifdef DIAGNOSTIC 171 static int ipprintfs = 0; 172 #endif 173 174 static struct ifqueue ipintrq; 175 static int ipqmaxlen = IFQ_MAXLEN; 176 177 extern struct domain inetdomain; 178 extern struct ipprotosw inetsw[]; 179 u_char ip_protox[IPPROTO_MAX]; 180 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 181 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 182 u_long in_ifaddrhmask; /* mask for hash table */ 183 184 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 185 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 186 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 187 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 188 189 struct ip_stats ipstats_ary[MAXCPU]; 190 #ifdef SMP 191 static int 192 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 193 { 194 int cpu, error = 0; 195 196 for (cpu = 0; cpu < ncpus; ++cpu) { 197 if ((error = SYSCTL_OUT(req, (void *)&ipstats_ary[cpu], 198 sizeof(struct ip_stats)))) 199 break; 200 if ((error = SYSCTL_IN(req, (void *)&ipstats_ary[cpu], 201 sizeof(struct ip_stats)))) 202 break; 203 } 204 205 return (error); 206 } 207 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 208 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 209 #else 210 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 211 &ipstat, ip_stats, "IP statistics"); 212 #endif 213 214 /* Packet reassembly stuff */ 215 #define IPREASS_NHASH_LOG2 6 216 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 217 #define IPREASS_HMASK (IPREASS_NHASH - 1) 218 #define IPREASS_HASH(x,y) \ 219 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 220 221 static struct ipq ipq[IPREASS_NHASH]; 222 const int ipintrq_present = 1; 223 224 #ifdef IPCTL_DEFMTU 225 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 226 &ip_mtu, 0, "Default MTU"); 227 #endif 228 229 #ifdef IPSTEALTH 230 static int ipstealth = 0; 231 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, ""); 232 #else 233 static const int ipstealth = 0; 234 #endif 235 236 237 /* Firewall hooks */ 238 ip_fw_chk_t *ip_fw_chk_ptr; 239 int fw_enable = 1; 240 int fw_one_pass = 1; 241 242 /* Dummynet hooks */ 243 ip_dn_io_t *ip_dn_io_ptr; 244 245 #ifdef PFIL_HOOKS 246 struct pfil_head inet_pfil_hook; 247 #endif 248 249 /* 250 * XXX this is ugly -- the following two global variables are 251 * used to store packet state while it travels through the stack. 252 * Note that the code even makes assumptions on the size and 253 * alignment of fields inside struct ip_srcrt so e.g. adding some 254 * fields will break the code. This needs to be fixed. 255 * 256 * We need to save the IP options in case a protocol wants to respond 257 * to an incoming packet over the same route if the packet got here 258 * using IP source routing. This allows connection establishment and 259 * maintenance when the remote end is on a network that is not known 260 * to us. 261 */ 262 static int ip_nhops = 0; 263 264 static struct ip_srcrt { 265 struct in_addr dst; /* final destination */ 266 char nop; /* one NOP to align */ 267 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 268 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 269 } ip_srcrt; 270 271 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 272 static struct malloc_pipe ipq_mpipe; 273 274 static void save_rte (u_char *, struct in_addr); 275 static int ip_dooptions (struct mbuf *m, int, 276 struct sockaddr_in *next_hop); 277 static void ip_forward (struct mbuf *m, int srcrt, 278 struct sockaddr_in *next_hop); 279 static void ip_freef (struct ipq *); 280 static int ip_input_handler (struct netmsg *); 281 static struct mbuf *ip_reass (struct mbuf *, struct ipq *, 282 struct ipq *, u_int32_t *, u_int16_t *); 283 284 /* 285 * IP initialization: fill in IP protocol switch table. 286 * All protocols not implemented in kernel go to raw IP protocol handler. 287 */ 288 void 289 ip_init(void) 290 { 291 struct ipprotosw *pr; 292 int i; 293 #ifdef SMP 294 int cpu; 295 #endif 296 297 /* 298 * Make sure we can handle a reasonable number of fragments but 299 * cap it at 4000 (XXX). 300 */ 301 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 302 IFQ_MAXLEN, 4000, 0, NULL); 303 TAILQ_INIT(&in_ifaddrhead); 304 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 305 pr = (struct ipprotosw *)pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 306 if (pr == NULL) 307 panic("ip_init"); 308 for (i = 0; i < IPPROTO_MAX; i++) 309 ip_protox[i] = pr - inetsw; 310 for (pr = (struct ipprotosw *)inetdomain.dom_protosw; 311 pr < (struct ipprotosw *)inetdomain.dom_protoswNPROTOSW; pr++) 312 if (pr->pr_domain->dom_family == PF_INET && 313 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 314 ip_protox[pr->pr_protocol] = pr - inetsw; 315 316 #ifdef PFIL_HOOKS 317 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 318 inet_pfil_hook.ph_af = AF_INET; 319 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 320 printf("%s: WARNING: unable to register pfil hook, " 321 "error %d\n", __func__, i); 322 #endif 323 324 for (i = 0; i < IPREASS_NHASH; i++) 325 ipq[i].next = ipq[i].prev = &ipq[i]; 326 327 maxnipq = nmbclusters / 32; 328 maxfragsperpacket = 16; 329 330 #ifndef RANDOM_IP_ID 331 ip_id = time_second & 0xffff; 332 #endif 333 ipintrq.ifq_maxlen = ipqmaxlen; 334 335 /* 336 * Initialize IP statistics. 337 * 338 * It is layed out as an array which is has one element for UP, 339 * and SMP_MAXCPU elements for SMP. This allows us to retain 340 * the access mechanism from userland for both UP and SMP. 341 */ 342 #ifdef SMP 343 for (cpu = 0; cpu < ncpus; ++cpu) { 344 bzero(&ipstats_ary[cpu], sizeof(struct ip_stats)); 345 } 346 #else 347 bzero(&ipstat, sizeof(struct ip_stats)); 348 #endif 349 350 netisr_register(NETISR_IP, ip_mport, ip_input_handler); 351 } 352 353 /* 354 * XXX watch out this one. It is perhaps used as a cache for 355 * the most recently used route ? it is cleared in in_addroute() 356 * when a new route is successfully created. 357 */ 358 struct route ipforward_rt; 359 static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 360 361 /* Do transport protocol processing. */ 362 static void 363 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip, 364 struct sockaddr_in *nexthop) 365 { 366 /* 367 * Switch out to protocol's input routine. 368 */ 369 if (nexthop && ip->ip_p == IPPROTO_TCP) { 370 /* TCP needs IPFORWARD info if available */ 371 struct m_hdr tag; 372 373 tag.mh_type = MT_TAG; 374 tag.mh_flags = PACKET_TAG_IPFORWARD; 375 tag.mh_data = (caddr_t)nexthop; 376 tag.mh_next = m; 377 378 (*inetsw[ip_protox[ip->ip_p]].pr_input) 379 ((struct mbuf *)&tag, hlen, ip->ip_p); 380 } else { 381 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, ip->ip_p); 382 } 383 } 384 385 struct netmsg_transport_packet { 386 struct lwkt_msg nm_lmsg; 387 struct mbuf *nm_mbuf; 388 int nm_hlen; 389 boolean_t nm_hasnexthop; 390 struct sockaddr_in nm_nexthop; 391 }; 392 393 static int 394 transport_processing_handler(lwkt_msg_t lmsg) 395 { 396 struct netmsg_transport_packet *msg = (void *)lmsg; 397 struct sockaddr_in *nexthop; 398 struct ip *ip; 399 400 ip = mtod(msg->nm_mbuf, struct ip *); 401 nexthop = msg->nm_hasnexthop ? &msg->nm_nexthop : NULL; 402 transport_processing_oncpu(msg->nm_mbuf, msg->nm_hlen, ip, nexthop); 403 lwkt_replymsg(lmsg, 0); 404 return(EASYNC); 405 } 406 407 static int 408 ip_input_handler(struct netmsg *msg0) 409 { 410 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet; 411 412 ip_input(m); 413 lwkt_replymsg(&msg0->nm_lmsg, 0); 414 return(EASYNC); 415 } 416 417 /* 418 * Ip input routine. Checksum and byte swap header. If fragmented 419 * try to reassemble. Process options. Pass to next level. 420 */ 421 void 422 ip_input(struct mbuf *m) 423 { 424 struct ip *ip; 425 struct ipq *fp; 426 struct in_ifaddr *ia = NULL; 427 struct ifaddr *ifa; 428 int i, hlen, checkif; 429 u_short sum; 430 struct in_addr pkt_dst; 431 u_int32_t divert_info = 0; /* packet divert/tee info */ 432 struct ip_fw_args args; 433 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 434 boolean_t needredispatch = FALSE; 435 #ifdef PFIL_HOOKS 436 struct in_addr odst; /* original dst address(NAT) */ 437 #endif 438 #ifdef FAST_IPSEC 439 struct m_tag *mtag; 440 struct tdb_ident *tdbi; 441 struct secpolicy *sp; 442 int s, error; 443 #endif 444 445 args.eh = NULL; 446 args.oif = NULL; 447 args.rule = NULL; 448 args.divert_rule = 0; /* divert cookie */ 449 args.next_hop = NULL; 450 451 /* Grab info from MT_TAG mbufs prepended to the chain. */ 452 for (; m && m->m_type == MT_TAG; m = m->m_next) { 453 switch(m->_m_tag_id) { 454 default: 455 printf("ip_input: unrecognised MT_TAG tag %d\n", 456 m->_m_tag_id); 457 break; 458 459 case PACKET_TAG_DUMMYNET: 460 args.rule = ((struct dn_pkt *)m)->rule; 461 break; 462 463 case PACKET_TAG_DIVERT: 464 args.divert_rule = (int)m->m_hdr.mh_data & 0xffff; 465 break; 466 467 case PACKET_TAG_IPFORWARD: 468 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 469 break; 470 } 471 } 472 473 KASSERT(m != NULL && (m->m_flags & M_PKTHDR) != 0, 474 ("ip_input: no HDR")); 475 476 if (args.rule) { /* dummynet already filtered us */ 477 ip = mtod(m, struct ip *); 478 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 479 goto iphack; 480 } 481 482 ipstat.ips_total++; 483 484 /* length checks already done in ip_demux() */ 485 KASSERT(m->m_len >= sizeof(ip), ("IP header not in one mbuf")); 486 487 ip = mtod(m, struct ip *); 488 489 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 490 ipstat.ips_badvers++; 491 goto bad; 492 } 493 494 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 495 /* length checks already done in ip_demux() */ 496 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 497 KASSERT(m->m_len >= hlen, ("packet shorter than IP header length")); 498 499 /* 127/8 must not appear on wire - RFC1122 */ 500 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 501 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 502 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 503 ipstat.ips_badaddr++; 504 goto bad; 505 } 506 } 507 508 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 509 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 510 } else { 511 if (hlen == sizeof(struct ip)) { 512 sum = in_cksum_hdr(ip); 513 } else { 514 sum = in_cksum(m, hlen); 515 } 516 } 517 if (sum) { 518 ipstat.ips_badsum++; 519 goto bad; 520 } 521 522 /* 523 * Convert fields to host representation. 524 */ 525 ip->ip_len = ntohs(ip->ip_len); 526 if (ip->ip_len < hlen) { 527 ipstat.ips_badlen++; 528 goto bad; 529 } 530 ip->ip_off = ntohs(ip->ip_off); 531 532 /* 533 * Check that the amount of data in the buffers 534 * is as at least much as the IP header would have us expect. 535 * Trim mbufs if longer than we expect. 536 * Drop packet if shorter than we expect. 537 */ 538 if (m->m_pkthdr.len < ip->ip_len) { 539 ipstat.ips_tooshort++; 540 goto bad; 541 } 542 if (m->m_pkthdr.len > ip->ip_len) { 543 if (m->m_len == m->m_pkthdr.len) { 544 m->m_len = ip->ip_len; 545 m->m_pkthdr.len = ip->ip_len; 546 } else 547 m_adj(m, ip->ip_len - m->m_pkthdr.len); 548 } 549 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 550 /* 551 * Bypass packet filtering for packets from a tunnel (gif). 552 */ 553 if (ipsec_gethist(m, NULL)) 554 goto pass; 555 #endif 556 557 /* 558 * IpHack's section. 559 * Right now when no processing on packet has done 560 * and it is still fresh out of network we do our black 561 * deals with it. 562 * - Firewall: deny/allow/divert 563 * - Xlate: translate packet's addr/port (NAT). 564 * - Pipe: pass pkt through dummynet. 565 * - Wrap: fake packet's addr/port <unimpl.> 566 * - Encapsulate: put it in another IP and send out. <unimp.> 567 */ 568 569 iphack: 570 571 #ifdef PFIL_HOOKS 572 /* 573 * Run through list of hooks for input packets. 574 * 575 * NB: Beware of the destination address changing (e.g. 576 * by NAT rewriting). When this happens, tell 577 * ip_forward to do the right thing. 578 */ 579 if (pfil_has_hooks(&inet_pfil_hook)) { 580 odst = ip->ip_dst; 581 if (pfil_run_hooks(&inet_pfil_hook, &m, 582 m->m_pkthdr.rcvif, PFIL_IN)) { 583 return; 584 } 585 if (m == NULL) /* consumed by filter */ 586 return; 587 ip = mtod(m, struct ip *); 588 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 589 } 590 #endif 591 592 if (fw_enable && IPFW_LOADED) { 593 /* 594 * If we've been forwarded from the output side, then 595 * skip the firewall a second time 596 */ 597 if (args.next_hop) 598 goto ours; 599 600 args.m = m; 601 i = ip_fw_chk_ptr(&args); 602 m = args.m; 603 604 if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 605 if (m) 606 m_freem(m); 607 return; 608 } 609 ip = mtod(m, struct ip *); /* just in case m changed */ 610 if (i == 0 && args.next_hop == NULL) /* common case */ 611 goto pass; 612 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG)) { 613 /* Send packet to the appropriate pipe */ 614 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 615 return; 616 } 617 #ifdef IPDIVERT 618 if (i != 0 && !(i & IP_FW_PORT_DYNT_FLAG)) { 619 /* Divert or tee packet */ 620 divert_info = i; 621 goto ours; 622 } 623 #endif 624 if (i == 0 && args.next_hop != NULL) 625 goto pass; 626 /* 627 * if we get here, the packet must be dropped 628 */ 629 m_freem(m); 630 return; 631 } 632 pass: 633 634 /* 635 * Process options and, if not destined for us, 636 * ship it on. ip_dooptions returns 1 when an 637 * error was detected (causing an icmp message 638 * to be sent and the original packet to be freed). 639 */ 640 ip_nhops = 0; /* for source routed packets */ 641 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, args.next_hop)) 642 return; 643 644 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 645 * matter if it is destined to another node, or whether it is 646 * a multicast one, RSVP wants it! and prevents it from being forwarded 647 * anywhere else. Also checks if the rsvp daemon is running before 648 * grabbing the packet. 649 */ 650 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 651 goto ours; 652 653 /* 654 * Check our list of addresses, to see if the packet is for us. 655 * If we don't have any addresses, assume any unicast packet 656 * we receive might be for us (and let the upper layers deal 657 * with it). 658 */ 659 if (TAILQ_EMPTY(&in_ifaddrhead) && !(m->m_flags & (M_MCAST | M_BCAST))) 660 goto ours; 661 662 /* 663 * Cache the destination address of the packet; this may be 664 * changed by use of 'ipfw fwd'. 665 */ 666 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 667 668 /* 669 * Enable a consistency check between the destination address 670 * and the arrival interface for a unicast packet (the RFC 1122 671 * strong ES model) if IP forwarding is disabled and the packet 672 * is not locally generated and the packet is not subject to 673 * 'ipfw fwd'. 674 * 675 * XXX - Checking also should be disabled if the destination 676 * address is ipnat'ed to a different interface. 677 * 678 * XXX - Checking is incompatible with IP aliases added 679 * to the loopback interface instead of the interface where 680 * the packets are received. 681 */ 682 checkif = ip_checkinterface && 683 !ipforwarding && 684 m->m_pkthdr.rcvif != NULL && 685 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 686 (args.next_hop == NULL); 687 688 /* 689 * Check for exact addresses in the hash bucket. 690 */ 691 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 692 /* 693 * If the address matches, verify that the packet 694 * arrived via the correct interface if checking is 695 * enabled. 696 */ 697 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 698 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 699 goto ours; 700 } 701 /* 702 * Check for broadcast addresses. 703 * 704 * Only accept broadcast packets that arrive via the matching 705 * interface. Reception of forwarded directed broadcasts would 706 * be handled via ip_forward() and ether_output() with the loopback 707 * into the stack for SIMPLEX interfaces handled by ether_output(). 708 */ 709 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 710 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 711 if (ifa->ifa_addr->sa_family != AF_INET) 712 continue; 713 ia = ifatoia(ifa); 714 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 715 pkt_dst.s_addr) 716 goto ours; 717 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 718 goto ours; 719 #ifdef BOOTP_COMPAT 720 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 721 goto ours; 722 #endif 723 } 724 } 725 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 726 struct in_multi *inm; 727 if (ip_mrouter) { 728 /* 729 * If we are acting as a multicast router, all 730 * incoming multicast packets are passed to the 731 * kernel-level multicast forwarding function. 732 * The packet is returned (relatively) intact; if 733 * ip_mforward() returns a non-zero value, the packet 734 * must be discarded, else it may be accepted below. 735 */ 736 if (ip_mforward && 737 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 738 ipstat.ips_cantforward++; 739 m_freem(m); 740 return; 741 } 742 743 /* 744 * The process-level routing daemon needs to receive 745 * all multicast IGMP packets, whether or not this 746 * host belongs to their destination groups. 747 */ 748 if (ip->ip_p == IPPROTO_IGMP) 749 goto ours; 750 ipstat.ips_forward++; 751 } 752 /* 753 * See if we belong to the destination multicast group on the 754 * arrival interface. 755 */ 756 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 757 if (inm == NULL) { 758 ipstat.ips_notmember++; 759 m_freem(m); 760 return; 761 } 762 goto ours; 763 } 764 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 765 goto ours; 766 if (ip->ip_dst.s_addr == INADDR_ANY) 767 goto ours; 768 769 /* 770 * FAITH(Firewall Aided Internet Translator) 771 */ 772 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 773 if (ip_keepfaith) { 774 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 775 goto ours; 776 } 777 m_freem(m); 778 return; 779 } 780 781 /* 782 * Not for us; forward if possible and desirable. 783 */ 784 if (!ipforwarding) { 785 ipstat.ips_cantforward++; 786 m_freem(m); 787 } else { 788 #ifdef IPSEC 789 /* 790 * Enforce inbound IPsec SPD. 791 */ 792 if (ipsec4_in_reject(m, NULL)) { 793 ipsecstat.in_polvio++; 794 goto bad; 795 } 796 #endif 797 #ifdef FAST_IPSEC 798 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 799 s = splnet(); 800 if (mtag != NULL) { 801 tdbi = (struct tdb_ident *)(mtag + 1); 802 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 803 } else { 804 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 805 IP_FORWARDING, &error); 806 } 807 if (sp == NULL) { /* NB: can happen if error */ 808 splx(s); 809 /*XXX error stat???*/ 810 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 811 goto bad; 812 } 813 814 /* 815 * Check security policy against packet attributes. 816 */ 817 error = ipsec_in_reject(sp, m); 818 KEY_FREESP(&sp); 819 splx(s); 820 if (error) { 821 ipstat.ips_cantforward++; 822 goto bad; 823 } 824 #endif 825 ip_forward(m, using_srcrt, args.next_hop); 826 } 827 return; 828 829 ours: 830 831 /* 832 * IPSTEALTH: Process non-routing options only 833 * if the packet is destined for us. 834 */ 835 if (ipstealth && 836 hlen > sizeof(struct ip) && 837 ip_dooptions(m, 1, args.next_hop)) 838 return; 839 840 /* Count the packet in the ip address stats */ 841 if (ia != NULL) { 842 ia->ia_ifa.if_ipackets++; 843 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 844 } 845 846 /* 847 * If offset or IP_MF are set, must reassemble. 848 * Otherwise, nothing need be done. 849 * (We could look in the reassembly queue to see 850 * if the packet was previously fragmented, 851 * but it's not worth the time; just let them time out.) 852 */ 853 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 854 855 /* If maxnipq is 0, never accept fragments. */ 856 if (maxnipq == 0) { 857 ipstat.ips_fragments++; 858 ipstat.ips_fragdropped++; 859 goto bad; 860 } 861 862 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 863 /* 864 * Look for queue of fragments 865 * of this datagram. 866 */ 867 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 868 if (ip->ip_id == fp->ipq_id && 869 ip->ip_src.s_addr == fp->ipq_src.s_addr && 870 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 871 ip->ip_p == fp->ipq_p) 872 goto found; 873 874 fp = NULL; 875 876 /* 877 * Enforce upper bound on number of fragmented packets 878 * for which we attempt reassembly; 879 * If maxnipq is -1, accept all fragments without limitation. 880 */ 881 if ((nipq > maxnipq) && (maxnipq > 0)) { 882 /* 883 * drop something from the tail of the current queue 884 * before proceeding further 885 */ 886 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 887 for (i = 0; i < IPREASS_NHASH; i++) { 888 if (ipq[i].prev != &ipq[i]) { 889 ipstat.ips_fragtimeout += 890 ipq[i].prev->ipq_nfrags; 891 ip_freef(ipq[i].prev); 892 break; 893 } 894 } 895 } else { 896 ipstat.ips_fragtimeout += 897 ipq[sum].prev->ipq_nfrags; 898 ip_freef(ipq[sum].prev); 899 } 900 } 901 found: 902 /* 903 * Adjust ip_len to not reflect header, 904 * convert offset of this to bytes. 905 */ 906 ip->ip_len -= hlen; 907 if (ip->ip_off & IP_MF) { 908 /* 909 * Make sure that fragments have a data length 910 * that's a non-zero multiple of 8 bytes. 911 */ 912 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 913 ipstat.ips_toosmall++; /* XXX */ 914 goto bad; 915 } 916 m->m_flags |= M_FRAG; 917 } else 918 m->m_flags &= ~M_FRAG; 919 ip->ip_off <<= 3; 920 921 /* 922 * Attempt reassembly; if it succeeds, proceed. 923 * ip_reass() will return a different mbuf, and update 924 * the divert info in divert_info and args.divert_rule. 925 */ 926 ipstat.ips_fragments++; 927 m->m_pkthdr.header = ip; 928 m = ip_reass(m, fp, &ipq[sum], &divert_info, &args.divert_rule); 929 if (m == NULL) 930 return; 931 ipstat.ips_reassembled++; 932 needredispatch = TRUE; 933 ip = mtod(m, struct ip *); 934 /* Get the header length of the reassembled packet */ 935 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 936 #ifdef IPDIVERT 937 /* Restore original checksum before diverting packet */ 938 if (divert_info != 0) { 939 ip->ip_len += hlen; 940 ip->ip_len = htons(ip->ip_len); 941 ip->ip_off = htons(ip->ip_off); 942 ip->ip_sum = 0; 943 if (hlen == sizeof(struct ip)) 944 ip->ip_sum = in_cksum_hdr(ip); 945 else 946 ip->ip_sum = in_cksum(m, hlen); 947 ip->ip_off = ntohs(ip->ip_off); 948 ip->ip_len = ntohs(ip->ip_len); 949 ip->ip_len -= hlen; 950 } 951 #endif 952 } else { 953 ip->ip_len -= hlen; 954 } 955 956 #ifdef IPDIVERT 957 /* 958 * Divert or tee packet to the divert protocol if required. 959 */ 960 if (divert_info != 0) { 961 struct mbuf *clone = NULL; 962 963 /* Clone packet if we're doing a 'tee' */ 964 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 965 clone = m_dup(m, MB_DONTWAIT); 966 967 /* Restore packet header fields to original values */ 968 ip->ip_len += hlen; 969 ip->ip_len = htons(ip->ip_len); 970 ip->ip_off = htons(ip->ip_off); 971 972 /* Deliver packet to divert input routine */ 973 divert_packet(m, 1, divert_info & 0xffff, args.divert_rule); 974 ipstat.ips_delivered++; 975 976 /* If 'tee', continue with original packet */ 977 if (clone == NULL) 978 return; 979 m = clone; 980 ip = mtod(m, struct ip *); 981 ip->ip_len += hlen; 982 /* 983 * Jump backwards to complete processing of the 984 * packet. But first clear divert_info to avoid 985 * entering this block again. 986 * We do not need to clear args.divert_rule 987 * or args.next_hop as they will not be used. 988 */ 989 divert_info = 0; 990 goto pass; 991 } 992 #endif 993 994 #ifdef IPSEC 995 /* 996 * enforce IPsec policy checking if we are seeing last header. 997 * note that we do not visit this with protocols with pcb layer 998 * code - like udp/tcp/raw ip. 999 */ 1000 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) && 1001 ipsec4_in_reject(m, NULL)) { 1002 ipsecstat.in_polvio++; 1003 goto bad; 1004 } 1005 #endif 1006 #if FAST_IPSEC 1007 /* 1008 * enforce IPsec policy checking if we are seeing last header. 1009 * note that we do not visit this with protocols with pcb layer 1010 * code - like udp/tcp/raw ip. 1011 */ 1012 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) { 1013 /* 1014 * Check if the packet has already had IPsec processing 1015 * done. If so, then just pass it along. This tag gets 1016 * set during AH, ESP, etc. input handling, before the 1017 * packet is returned to the ip input queue for delivery. 1018 */ 1019 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 1020 s = splnet(); 1021 if (mtag != NULL) { 1022 tdbi = (struct tdb_ident *)(mtag + 1); 1023 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 1024 } else { 1025 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 1026 IP_FORWARDING, &error); 1027 } 1028 if (sp != NULL) { 1029 /* 1030 * Check security policy against packet attributes. 1031 */ 1032 error = ipsec_in_reject(sp, m); 1033 KEY_FREESP(&sp); 1034 } else { 1035 /* XXX error stat??? */ 1036 error = EINVAL; 1037 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 1038 goto bad; 1039 } 1040 splx(s); 1041 if (error) 1042 goto bad; 1043 } 1044 #endif /* FAST_IPSEC */ 1045 1046 ipstat.ips_delivered++; 1047 if (needredispatch) { 1048 struct netmsg_transport_packet *msg; 1049 lwkt_port_t port; 1050 1051 msg = malloc(sizeof(struct netmsg_transport_packet), 1052 M_LWKTMSG, M_INTWAIT | M_NULLOK); 1053 if (msg == NULL) 1054 goto bad; 1055 1056 lwkt_initmsg(&msg->nm_lmsg, &netisr_afree_rport, 0, 1057 lwkt_cmd_func(transport_processing_handler), 1058 lwkt_cmd_op_none); 1059 msg->nm_mbuf = m; 1060 msg->nm_hlen = hlen; 1061 msg->nm_hasnexthop = (args.next_hop != NULL); 1062 if (msg->nm_hasnexthop) 1063 msg->nm_nexthop = *args.next_hop; /* structure copy */ 1064 1065 ip->ip_off = htons(ip->ip_off); 1066 ip->ip_len = htons(ip->ip_len); 1067 port = ip_mport(m); 1068 if (port == NULL) 1069 goto bad; 1070 ip->ip_len = ntohs(ip->ip_len); 1071 ip->ip_off = ntohs(ip->ip_off); 1072 1073 lwkt_sendmsg(port, &msg->nm_lmsg); 1074 } else { 1075 transport_processing_oncpu(m, hlen, ip, args.next_hop); 1076 } 1077 return; 1078 1079 bad: 1080 m_freem(m); 1081 } 1082 1083 /* 1084 * Take incoming datagram fragment and try to reassemble it into 1085 * whole datagram. If a chain for reassembly of this datagram already 1086 * exists, then it is given as fp; otherwise have to make a chain. 1087 * 1088 * When IPDIVERT enabled, keep additional state with each packet that 1089 * tells us if we need to divert or tee the packet we're building. 1090 * In particular, *divinfo includes the port and TEE flag, 1091 * *divert_rule is the number of the matching rule. 1092 */ 1093 1094 static struct mbuf * 1095 ip_reass(struct mbuf *m, struct ipq *fp, struct ipq *where, 1096 u_int32_t *divinfo, u_int16_t *divert_rule) 1097 { 1098 struct ip *ip = mtod(m, struct ip *); 1099 struct mbuf *p = NULL, *q, *nq; 1100 struct mbuf *n; 1101 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 1102 int i, next; 1103 1104 /* 1105 * Presence of header sizes in mbufs 1106 * would confuse code below. 1107 */ 1108 m->m_data += hlen; 1109 m->m_len -= hlen; 1110 1111 /* 1112 * If first fragment to arrive, create a reassembly queue. 1113 */ 1114 if (fp == NULL) { 1115 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1116 goto dropfrag; 1117 insque(fp, where); 1118 nipq++; 1119 fp->ipq_nfrags = 1; 1120 fp->ipq_ttl = IPFRAGTTL; 1121 fp->ipq_p = ip->ip_p; 1122 fp->ipq_id = ip->ip_id; 1123 fp->ipq_src = ip->ip_src; 1124 fp->ipq_dst = ip->ip_dst; 1125 fp->ipq_frags = m; 1126 m->m_nextpkt = NULL; 1127 #ifdef IPDIVERT 1128 fp->ipq_div_info = 0; 1129 fp->ipq_div_cookie = 0; 1130 #endif 1131 goto inserted; 1132 } else { 1133 fp->ipq_nfrags++; 1134 } 1135 1136 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1137 1138 /* 1139 * Find a segment which begins after this one does. 1140 */ 1141 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1142 if (GETIP(q)->ip_off > ip->ip_off) 1143 break; 1144 1145 /* 1146 * If there is a preceding segment, it may provide some of 1147 * our data already. If so, drop the data from the incoming 1148 * segment. If it provides all of our data, drop us, otherwise 1149 * stick new segment in the proper place. 1150 * 1151 * If some of the data is dropped from the the preceding 1152 * segment, then it's checksum is invalidated. 1153 */ 1154 if (p) { 1155 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1156 if (i > 0) { 1157 if (i >= ip->ip_len) 1158 goto dropfrag; 1159 m_adj(m, i); 1160 m->m_pkthdr.csum_flags = 0; 1161 ip->ip_off += i; 1162 ip->ip_len -= i; 1163 } 1164 m->m_nextpkt = p->m_nextpkt; 1165 p->m_nextpkt = m; 1166 } else { 1167 m->m_nextpkt = fp->ipq_frags; 1168 fp->ipq_frags = m; 1169 } 1170 1171 /* 1172 * While we overlap succeeding segments trim them or, 1173 * if they are completely covered, dequeue them. 1174 */ 1175 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1176 q = nq) { 1177 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1178 if (i < GETIP(q)->ip_len) { 1179 GETIP(q)->ip_len -= i; 1180 GETIP(q)->ip_off += i; 1181 m_adj(q, i); 1182 q->m_pkthdr.csum_flags = 0; 1183 break; 1184 } 1185 nq = q->m_nextpkt; 1186 m->m_nextpkt = nq; 1187 ipstat.ips_fragdropped++; 1188 fp->ipq_nfrags--; 1189 m_freem(q); 1190 } 1191 1192 inserted: 1193 1194 #ifdef IPDIVERT 1195 /* 1196 * Transfer firewall instructions to the fragment structure. 1197 * Only trust info in the fragment at offset 0. 1198 */ 1199 if (ip->ip_off == 0) { 1200 fp->ipq_div_info = *divinfo; 1201 fp->ipq_div_cookie = *divert_rule; 1202 } 1203 *divinfo = 0; 1204 *divert_rule = 0; 1205 #endif 1206 1207 /* 1208 * Check for complete reassembly and perform frag per packet 1209 * limiting. 1210 * 1211 * Frag limiting is performed here so that the nth frag has 1212 * a chance to complete the packet before we drop the packet. 1213 * As a result, n+1 frags are actually allowed per packet, but 1214 * only n will ever be stored. (n = maxfragsperpacket.) 1215 * 1216 */ 1217 next = 0; 1218 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1219 if (GETIP(q)->ip_off != next) { 1220 if (fp->ipq_nfrags > maxfragsperpacket) { 1221 ipstat.ips_fragdropped += fp->ipq_nfrags; 1222 ip_freef(fp); 1223 } 1224 return (NULL); 1225 } 1226 next += GETIP(q)->ip_len; 1227 } 1228 /* Make sure the last packet didn't have the IP_MF flag */ 1229 if (p->m_flags & M_FRAG) { 1230 if (fp->ipq_nfrags > maxfragsperpacket) { 1231 ipstat.ips_fragdropped += fp->ipq_nfrags; 1232 ip_freef(fp); 1233 } 1234 return (NULL); 1235 } 1236 1237 /* 1238 * Reassembly is complete. Make sure the packet is a sane size. 1239 */ 1240 q = fp->ipq_frags; 1241 ip = GETIP(q); 1242 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1243 ipstat.ips_toolong++; 1244 ipstat.ips_fragdropped += fp->ipq_nfrags; 1245 ip_freef(fp); 1246 return (NULL); 1247 } 1248 1249 /* 1250 * Concatenate fragments. 1251 */ 1252 m = q; 1253 n = m->m_next; 1254 m->m_next = NULL; 1255 m_cat(m, n); 1256 nq = q->m_nextpkt; 1257 q->m_nextpkt = NULL; 1258 for (q = nq; q != NULL; q = nq) { 1259 nq = q->m_nextpkt; 1260 q->m_nextpkt = NULL; 1261 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1262 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1263 m_cat(m, q); 1264 } 1265 1266 #ifdef IPDIVERT 1267 /* 1268 * Extract firewall instructions from the fragment structure. 1269 */ 1270 *divinfo = fp->ipq_div_info; 1271 *divert_rule = fp->ipq_div_cookie; 1272 #endif 1273 1274 /* 1275 * Create header for new ip packet by 1276 * modifying header of first packet; 1277 * dequeue and discard fragment reassembly header. 1278 * Make header visible. 1279 */ 1280 ip->ip_len = next; 1281 ip->ip_src = fp->ipq_src; 1282 ip->ip_dst = fp->ipq_dst; 1283 remque(fp); 1284 nipq--; 1285 mpipe_free(&ipq_mpipe, fp); 1286 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1287 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1288 /* some debugging cruft by sklower, below, will go away soon */ 1289 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1290 int plen = 0; 1291 1292 for (n = m; n; n = n->m_next) 1293 plen += n->m_len; 1294 m->m_pkthdr.len = plen; 1295 } 1296 return (m); 1297 1298 dropfrag: 1299 #ifdef IPDIVERT 1300 *divinfo = 0; 1301 *divert_rule = 0; 1302 #endif 1303 ipstat.ips_fragdropped++; 1304 if (fp != NULL) 1305 fp->ipq_nfrags--; 1306 m_freem(m); 1307 return (NULL); 1308 1309 #undef GETIP 1310 } 1311 1312 /* 1313 * Free a fragment reassembly header and all 1314 * associated datagrams. 1315 */ 1316 static void 1317 ip_freef(struct ipq *fp) 1318 { 1319 struct mbuf *q; 1320 1321 while (fp->ipq_frags) { 1322 q = fp->ipq_frags; 1323 fp->ipq_frags = q->m_nextpkt; 1324 m_freem(q); 1325 } 1326 remque(fp); 1327 mpipe_free(&ipq_mpipe, fp); 1328 nipq--; 1329 } 1330 1331 /* 1332 * IP timer processing; 1333 * if a timer expires on a reassembly 1334 * queue, discard it. 1335 */ 1336 void 1337 ip_slowtimo(void) 1338 { 1339 struct ipq *fp; 1340 int s = splnet(); 1341 int i; 1342 1343 for (i = 0; i < IPREASS_NHASH; i++) { 1344 fp = ipq[i].next; 1345 if (fp == NULL) 1346 continue; 1347 while (fp != &ipq[i]) { 1348 --fp->ipq_ttl; 1349 fp = fp->next; 1350 if (fp->prev->ipq_ttl == 0) { 1351 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags; 1352 ip_freef(fp->prev); 1353 } 1354 } 1355 } 1356 /* 1357 * If we are over the maximum number of fragments 1358 * (due to the limit being lowered), drain off 1359 * enough to get down to the new limit. 1360 */ 1361 if (maxnipq >= 0 && nipq > maxnipq) { 1362 for (i = 0; i < IPREASS_NHASH; i++) { 1363 while (nipq > maxnipq && 1364 (ipq[i].next != &ipq[i])) { 1365 ipstat.ips_fragdropped += 1366 ipq[i].next->ipq_nfrags; 1367 ip_freef(ipq[i].next); 1368 } 1369 } 1370 } 1371 ipflow_slowtimo(); 1372 splx(s); 1373 } 1374 1375 /* 1376 * Drain off all datagram fragments. 1377 */ 1378 void 1379 ip_drain(void) 1380 { 1381 int i; 1382 1383 for (i = 0; i < IPREASS_NHASH; i++) { 1384 while (ipq[i].next != &ipq[i]) { 1385 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags; 1386 ip_freef(ipq[i].next); 1387 } 1388 } 1389 in_rtqdrain(); 1390 } 1391 1392 /* 1393 * Do option processing on a datagram, 1394 * possibly discarding it if bad options are encountered, 1395 * or forwarding it if source-routed. 1396 * The pass argument is used when operating in the IPSTEALTH 1397 * mode to tell what options to process: 1398 * [LS]SRR (pass 0) or the others (pass 1). 1399 * The reason for as many as two passes is that when doing IPSTEALTH, 1400 * non-routing options should be processed only if the packet is for us. 1401 * Returns 1 if packet has been forwarded/freed, 1402 * 0 if the packet should be processed further. 1403 */ 1404 static int 1405 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1406 { 1407 struct ip *ip = mtod(m, struct ip *); 1408 u_char *cp; 1409 struct in_ifaddr *ia; 1410 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1411 boolean_t forward = FALSE; 1412 struct in_addr *sin, dst; 1413 n_time ntime; 1414 1415 dst = ip->ip_dst; 1416 cp = (u_char *)(ip + 1); 1417 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1418 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1419 opt = cp[IPOPT_OPTVAL]; 1420 if (opt == IPOPT_EOL) 1421 break; 1422 if (opt == IPOPT_NOP) 1423 optlen = 1; 1424 else { 1425 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1426 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1427 goto bad; 1428 } 1429 optlen = cp[IPOPT_OLEN]; 1430 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1431 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1432 goto bad; 1433 } 1434 } 1435 switch (opt) { 1436 1437 default: 1438 break; 1439 1440 /* 1441 * Source routing with record. 1442 * Find interface with current destination address. 1443 * If none on this machine then drop if strictly routed, 1444 * or do nothing if loosely routed. 1445 * Record interface address and bring up next address 1446 * component. If strictly routed make sure next 1447 * address is on directly accessible net. 1448 */ 1449 case IPOPT_LSRR: 1450 case IPOPT_SSRR: 1451 if (ipstealth && pass > 0) 1452 break; 1453 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1454 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1455 goto bad; 1456 } 1457 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1458 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1459 goto bad; 1460 } 1461 ipaddr.sin_addr = ip->ip_dst; 1462 ia = (struct in_ifaddr *) 1463 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1464 if (ia == NULL) { 1465 if (opt == IPOPT_SSRR) { 1466 type = ICMP_UNREACH; 1467 code = ICMP_UNREACH_SRCFAIL; 1468 goto bad; 1469 } 1470 if (!ip_dosourceroute) 1471 goto nosourcerouting; 1472 /* 1473 * Loose routing, and not at next destination 1474 * yet; nothing to do except forward. 1475 */ 1476 break; 1477 } 1478 off--; /* 0 origin */ 1479 if (off > optlen - (int)sizeof(struct in_addr)) { 1480 /* 1481 * End of source route. Should be for us. 1482 */ 1483 if (!ip_acceptsourceroute) 1484 goto nosourcerouting; 1485 save_rte(cp, ip->ip_src); 1486 break; 1487 } 1488 if (ipstealth) 1489 goto dropit; 1490 if (!ip_dosourceroute) { 1491 if (ipforwarding) { 1492 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1493 /* 1494 * Acting as a router, so generate ICMP 1495 */ 1496 nosourcerouting: 1497 strcpy(buf, inet_ntoa(ip->ip_dst)); 1498 log(LOG_WARNING, 1499 "attempted source route from %s to %s\n", 1500 inet_ntoa(ip->ip_src), buf); 1501 type = ICMP_UNREACH; 1502 code = ICMP_UNREACH_SRCFAIL; 1503 goto bad; 1504 } else { 1505 /* 1506 * Not acting as a router, 1507 * so silently drop. 1508 */ 1509 dropit: 1510 ipstat.ips_cantforward++; 1511 m_freem(m); 1512 return (1); 1513 } 1514 } 1515 1516 /* 1517 * locate outgoing interface 1518 */ 1519 (void)memcpy(&ipaddr.sin_addr, cp + off, 1520 sizeof(ipaddr.sin_addr)); 1521 1522 if (opt == IPOPT_SSRR) { 1523 #define INA struct in_ifaddr * 1524 #define SA struct sockaddr * 1525 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1526 == NULL) 1527 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1528 } else 1529 ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt); 1530 if (ia == NULL) { 1531 type = ICMP_UNREACH; 1532 code = ICMP_UNREACH_SRCFAIL; 1533 goto bad; 1534 } 1535 ip->ip_dst = ipaddr.sin_addr; 1536 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1537 sizeof(struct in_addr)); 1538 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1539 /* 1540 * Let ip_intr's mcast routing check handle mcast pkts 1541 */ 1542 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1543 break; 1544 1545 case IPOPT_RR: 1546 if (ipstealth && pass == 0) 1547 break; 1548 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1549 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1550 goto bad; 1551 } 1552 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1553 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1554 goto bad; 1555 } 1556 /* 1557 * If no space remains, ignore. 1558 */ 1559 off--; /* 0 origin */ 1560 if (off > optlen - (int)sizeof(struct in_addr)) 1561 break; 1562 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1563 sizeof(ipaddr.sin_addr)); 1564 /* 1565 * locate outgoing interface; if we're the destination, 1566 * use the incoming interface (should be same). 1567 */ 1568 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1569 (ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt)) 1570 == NULL) { 1571 type = ICMP_UNREACH; 1572 code = ICMP_UNREACH_HOST; 1573 goto bad; 1574 } 1575 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1576 sizeof(struct in_addr)); 1577 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1578 break; 1579 1580 case IPOPT_TS: 1581 if (ipstealth && pass == 0) 1582 break; 1583 code = cp - (u_char *)ip; 1584 if (optlen < 4 || optlen > 40) { 1585 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1586 goto bad; 1587 } 1588 if ((off = cp[IPOPT_OFFSET]) < 5) { 1589 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1590 goto bad; 1591 } 1592 if (off > optlen - (int)sizeof(int32_t)) { 1593 cp[IPOPT_OFFSET + 1] += (1 << 4); 1594 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1595 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1596 goto bad; 1597 } 1598 break; 1599 } 1600 off--; /* 0 origin */ 1601 sin = (struct in_addr *)(cp + off); 1602 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1603 1604 case IPOPT_TS_TSONLY: 1605 break; 1606 1607 case IPOPT_TS_TSANDADDR: 1608 if (off + sizeof(n_time) + 1609 sizeof(struct in_addr) > optlen) { 1610 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1611 goto bad; 1612 } 1613 ipaddr.sin_addr = dst; 1614 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1615 m->m_pkthdr.rcvif); 1616 if (ia == NULL) 1617 continue; 1618 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1619 sizeof(struct in_addr)); 1620 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1621 off += sizeof(struct in_addr); 1622 break; 1623 1624 case IPOPT_TS_PRESPEC: 1625 if (off + sizeof(n_time) + 1626 sizeof(struct in_addr) > optlen) { 1627 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1628 goto bad; 1629 } 1630 (void)memcpy(&ipaddr.sin_addr, sin, 1631 sizeof(struct in_addr)); 1632 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1633 continue; 1634 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1635 off += sizeof(struct in_addr); 1636 break; 1637 1638 default: 1639 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1640 goto bad; 1641 } 1642 ntime = iptime(); 1643 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1644 cp[IPOPT_OFFSET] += sizeof(n_time); 1645 } 1646 } 1647 if (forward && ipforwarding) { 1648 ip_forward(m, 1, next_hop); 1649 return (1); 1650 } 1651 return (0); 1652 bad: 1653 icmp_error(m, type, code, 0, NULL); 1654 ipstat.ips_badoptions++; 1655 return (1); 1656 } 1657 1658 /* 1659 * Given address of next destination (final or next hop), 1660 * return internet address info of interface to be used to get there. 1661 */ 1662 struct in_ifaddr * 1663 ip_rtaddr(struct in_addr dst, struct route *rt) 1664 { 1665 struct sockaddr_in *sin; 1666 1667 sin = (struct sockaddr_in *)&rt->ro_dst; 1668 1669 if (rt->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1670 if (rt->ro_rt != NULL) { 1671 RTFREE(rt->ro_rt); 1672 rt->ro_rt = NULL; 1673 } 1674 sin->sin_family = AF_INET; 1675 sin->sin_len = sizeof(*sin); 1676 sin->sin_addr = dst; 1677 rtalloc_ign(rt, RTF_PRCLONING); 1678 } 1679 1680 if (rt->ro_rt == NULL) 1681 return (NULL); 1682 1683 return (ifatoia(rt->ro_rt->rt_ifa)); 1684 } 1685 1686 /* 1687 * Save incoming source route for use in replies, 1688 * to be picked up later by ip_srcroute if the receiver is interested. 1689 */ 1690 void 1691 save_rte(u_char *option, struct in_addr dst) 1692 { 1693 unsigned olen; 1694 1695 olen = option[IPOPT_OLEN]; 1696 #ifdef DIAGNOSTIC 1697 if (ipprintfs) 1698 printf("save_rte: olen %d\n", olen); 1699 #endif 1700 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1701 return; 1702 bcopy(option, ip_srcrt.srcopt, olen); 1703 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1704 ip_srcrt.dst = dst; 1705 } 1706 1707 /* 1708 * Retrieve incoming source route for use in replies, 1709 * in the same form used by setsockopt. 1710 * The first hop is placed before the options, will be removed later. 1711 */ 1712 struct mbuf * 1713 ip_srcroute(void) 1714 { 1715 struct in_addr *p, *q; 1716 struct mbuf *m; 1717 1718 if (ip_nhops == 0) 1719 return (NULL); 1720 m = m_get(MB_DONTWAIT, MT_HEADER); 1721 if (m == NULL) 1722 return (NULL); 1723 1724 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1725 1726 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1727 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1728 OPTSIZ; 1729 #ifdef DIAGNOSTIC 1730 if (ipprintfs) 1731 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1732 #endif 1733 1734 /* 1735 * First save first hop for return route 1736 */ 1737 p = &ip_srcrt.route[ip_nhops - 1]; 1738 *(mtod(m, struct in_addr *)) = *p--; 1739 #ifdef DIAGNOSTIC 1740 if (ipprintfs) 1741 printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr)); 1742 #endif 1743 1744 /* 1745 * Copy option fields and padding (nop) to mbuf. 1746 */ 1747 ip_srcrt.nop = IPOPT_NOP; 1748 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1749 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &ip_srcrt.nop, 1750 OPTSIZ); 1751 q = (struct in_addr *)(mtod(m, caddr_t) + 1752 sizeof(struct in_addr) + OPTSIZ); 1753 #undef OPTSIZ 1754 /* 1755 * Record return path as an IP source route, 1756 * reversing the path (pointers are now aligned). 1757 */ 1758 while (p >= ip_srcrt.route) { 1759 #ifdef DIAGNOSTIC 1760 if (ipprintfs) 1761 printf(" %lx", ntohl(q->s_addr)); 1762 #endif 1763 *q++ = *p--; 1764 } 1765 /* 1766 * Last hop goes to final destination. 1767 */ 1768 *q = ip_srcrt.dst; 1769 #ifdef DIAGNOSTIC 1770 if (ipprintfs) 1771 printf(" %lx\n", ntohl(q->s_addr)); 1772 #endif 1773 return (m); 1774 } 1775 1776 /* 1777 * Strip out IP options. 1778 */ 1779 void 1780 ip_stripoptions(struct mbuf *m) 1781 { 1782 int datalen; 1783 struct ip *ip = mtod(m, struct ip *); 1784 caddr_t opts; 1785 int optlen; 1786 1787 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1788 opts = (caddr_t)(ip + 1); 1789 datalen = m->m_len - (sizeof(struct ip) + optlen); 1790 bcopy(opts + optlen, opts, datalen); 1791 m->m_len -= optlen; 1792 if (m->m_flags & M_PKTHDR) 1793 m->m_pkthdr.len -= optlen; 1794 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1795 } 1796 1797 u_char inetctlerrmap[PRC_NCMDS] = { 1798 0, 0, 0, 0, 1799 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1800 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1801 EMSGSIZE, EHOSTUNREACH, 0, 0, 1802 0, 0, 0, 0, 1803 ENOPROTOOPT, ECONNREFUSED 1804 }; 1805 1806 /* 1807 * Forward a packet. If some error occurs return the sender 1808 * an icmp packet. Note we can't always generate a meaningful 1809 * icmp message because icmp doesn't have a large enough repertoire 1810 * of codes and types. 1811 * 1812 * If not forwarding, just drop the packet. This could be confusing 1813 * if ipforwarding was zero but some routing protocol was advancing 1814 * us as a gateway to somewhere. However, we must let the routing 1815 * protocol deal with that. 1816 * 1817 * The using_srcrt parameter indicates whether the packet is being forwarded 1818 * via a source route. 1819 */ 1820 static void 1821 ip_forward(struct mbuf *m, int using_srcrt, struct sockaddr_in *next_hop) 1822 { 1823 struct ip *ip = mtod(m, struct ip *); 1824 struct sockaddr_in *sin; 1825 struct rtentry *rt; 1826 int error, type = 0, code = 0; 1827 struct mbuf *mcopy; 1828 n_long dest; 1829 struct in_addr pkt_dst; 1830 struct ifnet *destifp; 1831 struct m_hdr tag; 1832 #if defined(IPSEC) || defined(FAST_IPSEC) 1833 struct ifnet dummyifp; 1834 #endif 1835 1836 dest = 0; 1837 /* 1838 * Cache the destination address of the packet; this may be 1839 * changed by use of 'ipfw fwd'. 1840 */ 1841 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 1842 1843 #ifdef DIAGNOSTIC 1844 if (ipprintfs) 1845 printf("forward: src %x dst %x ttl %x\n", 1846 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 1847 #endif 1848 1849 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 1850 ipstat.ips_cantforward++; 1851 m_freem(m); 1852 return; 1853 } 1854 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 1855 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, NULL); 1856 return; 1857 } 1858 1859 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1860 if ((rt = ipforward_rt.ro_rt) == NULL || 1861 pkt_dst.s_addr != sin->sin_addr.s_addr) { 1862 if (ipforward_rt.ro_rt != NULL) { 1863 RTFREE(ipforward_rt.ro_rt); 1864 ipforward_rt.ro_rt = NULL; 1865 } 1866 sin->sin_family = AF_INET; 1867 sin->sin_len = sizeof(*sin); 1868 sin->sin_addr = pkt_dst; 1869 1870 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1871 if (ipforward_rt.ro_rt == NULL) { 1872 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 1873 NULL); 1874 return; 1875 } 1876 rt = ipforward_rt.ro_rt; 1877 } 1878 1879 /* 1880 * Save the IP header and at most 8 bytes of the payload, 1881 * in case we need to generate an ICMP message to the src. 1882 * 1883 * XXX this can be optimized a lot by saving the data in a local 1884 * buffer on the stack (72 bytes at most), and only allocating the 1885 * mbuf if really necessary. The vast majority of the packets 1886 * are forwarded without having to send an ICMP back (either 1887 * because unnecessary, or because rate limited), so we are 1888 * really we are wasting a lot of work here. 1889 * 1890 * We don't use m_copy() because it might return a reference 1891 * to a shared cluster. Both this function and ip_output() 1892 * assume exclusive access to the IP header in `m', so any 1893 * data in a cluster may change before we reach icmp_error(). 1894 */ 1895 MGET(mcopy, MB_DONTWAIT, m->m_type); 1896 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) { 1897 /* 1898 * It's probably ok if the pkthdr dup fails (because 1899 * the deep copy of the tag chain failed), but for now 1900 * be conservative and just discard the copy since 1901 * code below may some day want the tags. 1902 */ 1903 m_free(mcopy); 1904 mcopy = NULL; 1905 } 1906 if (mcopy != NULL) { 1907 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1908 (int)ip->ip_len); 1909 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1910 } 1911 1912 if (!ipstealth) 1913 ip->ip_ttl -= IPTTLDEC; 1914 1915 /* 1916 * If forwarding packet using same interface that it came in on, 1917 * perhaps should send a redirect to sender to shortcut a hop. 1918 * Only send redirect if source is sending directly to us, 1919 * and if packet was not source routed (or has any options). 1920 * Also, don't send redirect if forwarding using a default route 1921 * or a route modified by a redirect. 1922 */ 1923 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1924 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 1925 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 1926 ipsendredirects && !using_srcrt && next_hop != NULL) { 1927 u_long src = ntohl(ip->ip_src.s_addr); 1928 1929 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1930 if (RTA(rt) != NULL && 1931 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1932 if (rt->rt_flags & RTF_GATEWAY) 1933 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1934 else 1935 dest = pkt_dst.s_addr; 1936 /* 1937 * Router requirements says to only send 1938 * host redirects. 1939 */ 1940 type = ICMP_REDIRECT; 1941 code = ICMP_REDIRECT_HOST; 1942 #ifdef DIAGNOSTIC 1943 if (ipprintfs) 1944 printf("redirect (%d) to %x\n", code, dest); 1945 #endif 1946 } 1947 } 1948 1949 if (next_hop) { 1950 /* Pass IPFORWARD info if available */ 1951 tag.mh_type = MT_TAG; 1952 tag.mh_flags = PACKET_TAG_IPFORWARD; 1953 tag.mh_data = (caddr_t)next_hop; 1954 tag.mh_next = m; 1955 m = (struct mbuf *)&tag; 1956 } 1957 1958 error = ip_output(m, NULL, &ipforward_rt, IP_FORWARDING, NULL, NULL); 1959 1960 if (error) 1961 ipstat.ips_cantforward++; 1962 else { 1963 ipstat.ips_forward++; 1964 if (type) 1965 ipstat.ips_redirectsent++; 1966 else { 1967 if (mcopy) { 1968 ipflow_create(&ipforward_rt, mcopy); 1969 m_freem(mcopy); 1970 } 1971 return; 1972 } 1973 } 1974 if (mcopy == NULL) 1975 return; 1976 destifp = NULL; 1977 1978 switch (error) { 1979 1980 case 0: /* forwarded, but need redirect */ 1981 /* type, code set above */ 1982 break; 1983 1984 case ENETUNREACH: /* shouldn't happen, checked above */ 1985 case EHOSTUNREACH: 1986 case ENETDOWN: 1987 case EHOSTDOWN: 1988 default: 1989 type = ICMP_UNREACH; 1990 code = ICMP_UNREACH_HOST; 1991 break; 1992 1993 case EMSGSIZE: 1994 type = ICMP_UNREACH; 1995 code = ICMP_UNREACH_NEEDFRAG; 1996 #ifdef IPSEC 1997 /* 1998 * If the packet is routed over IPsec tunnel, tell the 1999 * originator the tunnel MTU. 2000 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2001 * XXX quickhack!!! 2002 */ 2003 if (ipforward_rt.ro_rt != NULL) { 2004 struct secpolicy *sp = NULL; 2005 int ipsecerror; 2006 int ipsechdr; 2007 struct route *ro; 2008 2009 sp = ipsec4_getpolicybyaddr(mcopy, 2010 IPSEC_DIR_OUTBOUND, 2011 IP_FORWARDING, 2012 &ipsecerror); 2013 2014 if (sp == NULL) 2015 destifp = ipforward_rt.ro_rt->rt_ifp; 2016 else { 2017 /* count IPsec header size */ 2018 ipsechdr = ipsec4_hdrsiz(mcopy, 2019 IPSEC_DIR_OUTBOUND, 2020 NULL); 2021 2022 /* 2023 * find the correct route for outer IPv4 2024 * header, compute tunnel MTU. 2025 * 2026 * XXX BUG ALERT 2027 * The "dummyifp" code relies upon the fact 2028 * that icmp_error() touches only ifp->if_mtu. 2029 */ 2030 /*XXX*/ 2031 destifp = NULL; 2032 if (sp->req != NULL && sp->req->sav != NULL && 2033 sp->req->sav->sah != NULL) { 2034 ro = &sp->req->sav->sah->sa_route; 2035 if (ro->ro_rt != NULL && 2036 ro->ro_rt->rt_ifp != NULL) { 2037 dummyifp.if_mtu = 2038 ro->ro_rt->rt_ifp->if_mtu; 2039 dummyifp.if_mtu -= ipsechdr; 2040 destifp = &dummyifp; 2041 } 2042 } 2043 2044 key_freesp(sp); 2045 } 2046 } 2047 #elif FAST_IPSEC 2048 /* 2049 * If the packet is routed over IPsec tunnel, tell the 2050 * originator the tunnel MTU. 2051 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2052 * XXX quickhack!!! 2053 */ 2054 if (ipforward_rt.ro_rt != NULL) { 2055 struct secpolicy *sp = NULL; 2056 int ipsecerror; 2057 int ipsechdr; 2058 struct route *ro; 2059 2060 sp = ipsec_getpolicybyaddr(mcopy, 2061 IPSEC_DIR_OUTBOUND, 2062 IP_FORWARDING, 2063 &ipsecerror); 2064 2065 if (sp == NULL) 2066 destifp = ipforward_rt.ro_rt->rt_ifp; 2067 else { 2068 /* count IPsec header size */ 2069 ipsechdr = ipsec4_hdrsiz(mcopy, 2070 IPSEC_DIR_OUTBOUND, 2071 NULL); 2072 2073 /* 2074 * find the correct route for outer IPv4 2075 * header, compute tunnel MTU. 2076 * 2077 * XXX BUG ALERT 2078 * The "dummyifp" code relies upon the fact 2079 * that icmp_error() touches only ifp->if_mtu. 2080 */ 2081 /*XXX*/ 2082 destifp = NULL; 2083 if (sp->req != NULL && 2084 sp->req->sav != NULL && 2085 sp->req->sav->sah != NULL) { 2086 ro = &sp->req->sav->sah->sa_route; 2087 if (ro->ro_rt != NULL && 2088 ro->ro_rt->rt_ifp != NULL) { 2089 dummyifp.if_mtu = 2090 ro->ro_rt->rt_ifp->if_mtu; 2091 dummyifp.if_mtu -= ipsechdr; 2092 destifp = &dummyifp; 2093 } 2094 } 2095 2096 KEY_FREESP(&sp); 2097 } 2098 } 2099 #else /* !IPSEC && !FAST_IPSEC */ 2100 if (ipforward_rt.ro_rt != NULL) 2101 destifp = ipforward_rt.ro_rt->rt_ifp; 2102 #endif /*IPSEC*/ 2103 ipstat.ips_cantfrag++; 2104 break; 2105 2106 case ENOBUFS: 2107 /* 2108 * A router should not generate ICMP_SOURCEQUENCH as 2109 * required in RFC1812 Requirements for IP Version 4 Routers. 2110 * Source quench could be a big problem under DoS attacks, 2111 * or if the underlying interface is rate-limited. 2112 * Those who need source quench packets may re-enable them 2113 * via the net.inet.ip.sendsourcequench sysctl. 2114 */ 2115 if (!ip_sendsourcequench) { 2116 m_freem(mcopy); 2117 return; 2118 } else { 2119 type = ICMP_SOURCEQUENCH; 2120 code = 0; 2121 } 2122 break; 2123 2124 case EACCES: /* ipfw denied packet */ 2125 m_freem(mcopy); 2126 return; 2127 } 2128 icmp_error(mcopy, type, code, dest, destifp); 2129 } 2130 2131 void 2132 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2133 struct mbuf *m) 2134 { 2135 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2136 struct timeval tv; 2137 2138 microtime(&tv); 2139 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2140 SCM_TIMESTAMP, SOL_SOCKET); 2141 if (*mp) 2142 mp = &(*mp)->m_next; 2143 } 2144 if (inp->inp_flags & INP_RECVDSTADDR) { 2145 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2146 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2147 if (*mp) 2148 mp = &(*mp)->m_next; 2149 } 2150 #ifdef notyet 2151 /* XXX 2152 * Moving these out of udp_input() made them even more broken 2153 * than they already were. 2154 */ 2155 /* options were tossed already */ 2156 if (inp->inp_flags & INP_RECVOPTS) { 2157 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2158 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2159 if (*mp) 2160 mp = &(*mp)->m_next; 2161 } 2162 /* ip_srcroute doesn't do what we want here, need to fix */ 2163 if (inp->inp_flags & INP_RECVRETOPTS) { 2164 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2165 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2166 if (*mp) 2167 mp = &(*mp)->m_next; 2168 } 2169 #endif 2170 if (inp->inp_flags & INP_RECVIF) { 2171 struct ifnet *ifp; 2172 struct sdlbuf { 2173 struct sockaddr_dl sdl; 2174 u_char pad[32]; 2175 } sdlbuf; 2176 struct sockaddr_dl *sdp; 2177 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2178 2179 if (((ifp = m->m_pkthdr.rcvif)) && 2180 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2181 sdp = (struct sockaddr_dl *) 2182 ifnet_addrs[ifp->if_index - 1]->ifa_addr; 2183 /* 2184 * Change our mind and don't try copy. 2185 */ 2186 if ((sdp->sdl_family != AF_LINK) || 2187 (sdp->sdl_len > sizeof(sdlbuf))) { 2188 goto makedummy; 2189 } 2190 bcopy(sdp, sdl2, sdp->sdl_len); 2191 } else { 2192 makedummy: 2193 sdl2->sdl_len = 2194 offsetof(struct sockaddr_dl, sdl_data[0]); 2195 sdl2->sdl_family = AF_LINK; 2196 sdl2->sdl_index = 0; 2197 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2198 } 2199 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2200 IP_RECVIF, IPPROTO_IP); 2201 if (*mp) 2202 mp = &(*mp)->m_next; 2203 } 2204 } 2205 2206 /* 2207 * XXX these routines are called from the upper part of the kernel. 2208 * 2209 * They could also be moved to ip_mroute.c, since all the RSVP 2210 * handling is done there already. 2211 */ 2212 int 2213 ip_rsvp_init(struct socket *so) 2214 { 2215 if (so->so_type != SOCK_RAW || 2216 so->so_proto->pr_protocol != IPPROTO_RSVP) 2217 return EOPNOTSUPP; 2218 2219 if (ip_rsvpd != NULL) 2220 return EADDRINUSE; 2221 2222 ip_rsvpd = so; 2223 /* 2224 * This may seem silly, but we need to be sure we don't over-increment 2225 * the RSVP counter, in case something slips up. 2226 */ 2227 if (!ip_rsvp_on) { 2228 ip_rsvp_on = 1; 2229 rsvp_on++; 2230 } 2231 2232 return 0; 2233 } 2234 2235 int 2236 ip_rsvp_done(void) 2237 { 2238 ip_rsvpd = NULL; 2239 /* 2240 * This may seem silly, but we need to be sure we don't over-decrement 2241 * the RSVP counter, in case something slips up. 2242 */ 2243 if (ip_rsvp_on) { 2244 ip_rsvp_on = 0; 2245 rsvp_on--; 2246 } 2247 return 0; 2248 } 2249 2250 void 2251 rsvp_input(struct mbuf *m, ...) /* XXX must fixup manually */ 2252 { 2253 int off, proto; 2254 __va_list ap; 2255 2256 __va_start(ap, m); 2257 off = __va_arg(ap, int); 2258 proto = __va_arg(ap, int); 2259 __va_end(ap); 2260 2261 if (rsvp_input_p) { /* call the real one if loaded */ 2262 rsvp_input_p(m, off, proto); 2263 return; 2264 } 2265 2266 /* Can still get packets with rsvp_on = 0 if there is a local member 2267 * of the group to which the RSVP packet is addressed. But in this 2268 * case we want to throw the packet away. 2269 */ 2270 2271 if (!rsvp_on) { 2272 m_freem(m); 2273 return; 2274 } 2275 2276 if (ip_rsvpd != NULL) { 2277 rip_input(m, off, proto); 2278 return; 2279 } 2280 /* Drop the packet */ 2281 m_freem(m); 2282 } 2283