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 * $FreeBSD$ 35 */ 36 37 #include "opt_bootp.h" 38 #include "opt_ipfw.h" 39 #include "opt_ipdn.h" 40 #include "opt_ipdivert.h" 41 #include "opt_ipfilter.h" 42 #include "opt_ipstealth.h" 43 #include "opt_ipsec.h" 44 #include "opt_mac.h" 45 #include "opt_pfil_hooks.h" 46 #include "opt_random_ip_id.h" 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/mac.h> 51 #include <sys/mbuf.h> 52 #include <sys/malloc.h> 53 #include <sys/domain.h> 54 #include <sys/protosw.h> 55 #include <sys/socket.h> 56 #include <sys/time.h> 57 #include <sys/kernel.h> 58 #include <sys/syslog.h> 59 #include <sys/sysctl.h> 60 61 #include <net/pfil.h> 62 #include <net/if.h> 63 #include <net/if_types.h> 64 #include <net/if_var.h> 65 #include <net/if_dl.h> 66 #include <net/route.h> 67 #include <net/netisr.h> 68 69 #include <netinet/in.h> 70 #include <netinet/in_systm.h> 71 #include <netinet/in_var.h> 72 #include <netinet/ip.h> 73 #include <netinet/in_pcb.h> 74 #include <netinet/ip_var.h> 75 #include <netinet/ip_icmp.h> 76 #include <machine/in_cksum.h> 77 78 #include <sys/socketvar.h> 79 80 #include <netinet/ip_fw.h> 81 #include <netinet/ip_dummynet.h> 82 83 #ifdef IPSEC 84 #include <netinet6/ipsec.h> 85 #include <netkey/key.h> 86 #endif 87 88 #ifdef FAST_IPSEC 89 #include <netipsec/ipsec.h> 90 #include <netipsec/key.h> 91 #endif 92 93 int rsvp_on = 0; 94 95 int ipforwarding = 0; 96 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 97 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 98 99 static int ipsendredirects = 1; /* XXX */ 100 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 101 &ipsendredirects, 0, "Enable sending IP redirects"); 102 103 int ip_defttl = IPDEFTTL; 104 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 105 &ip_defttl, 0, "Maximum TTL on IP packets"); 106 107 static int ip_dosourceroute = 0; 108 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 109 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 110 111 static int ip_acceptsourceroute = 0; 112 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 113 CTLFLAG_RW, &ip_acceptsourceroute, 0, 114 "Enable accepting source routed IP packets"); 115 116 static int ip_keepfaith = 0; 117 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 118 &ip_keepfaith, 0, 119 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 120 121 static int nipq = 0; /* total # of reass queues */ 122 static int maxnipq; 123 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 124 &maxnipq, 0, 125 "Maximum number of IPv4 fragment reassembly queue entries"); 126 127 static int maxfragsperpacket; 128 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 129 &maxfragsperpacket, 0, 130 "Maximum number of IPv4 fragments allowed per packet"); 131 132 static int ip_sendsourcequench = 0; 133 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 134 &ip_sendsourcequench, 0, 135 "Enable the transmission of source quench packets"); 136 137 /* 138 * XXX - Setting ip_checkinterface mostly implements the receive side of 139 * the Strong ES model described in RFC 1122, but since the routing table 140 * and transmit implementation do not implement the Strong ES model, 141 * setting this to 1 results in an odd hybrid. 142 * 143 * XXX - ip_checkinterface currently must be disabled if you use ipnat 144 * to translate the destination address to another local interface. 145 * 146 * XXX - ip_checkinterface must be disabled if you add IP aliases 147 * to the loopback interface instead of the interface where the 148 * packets for those addresses are received. 149 */ 150 static int ip_checkinterface = 1; 151 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 152 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 153 154 #ifdef DIAGNOSTIC 155 static int ipprintfs = 0; 156 #endif 157 158 static struct ifqueue ipintrq; 159 static int ipqmaxlen = IFQ_MAXLEN; 160 161 extern struct domain inetdomain; 162 extern struct protosw inetsw[]; 163 u_char ip_protox[IPPROTO_MAX]; 164 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 165 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 166 u_long in_ifaddrhmask; /* mask for hash table */ 167 168 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 169 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 170 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 171 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 172 173 struct ipstat ipstat; 174 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 175 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 176 177 /* Packet reassembly stuff */ 178 #define IPREASS_NHASH_LOG2 6 179 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 180 #define IPREASS_HMASK (IPREASS_NHASH - 1) 181 #define IPREASS_HASH(x,y) \ 182 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 183 184 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 185 struct mtx ipqlock; 186 187 #define IPQ_LOCK() mtx_lock(&ipqlock) 188 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 189 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF); 190 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED); 191 192 #ifdef IPCTL_DEFMTU 193 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 194 &ip_mtu, 0, "Default MTU"); 195 #endif 196 197 #ifdef IPSTEALTH 198 static int ipstealth = 0; 199 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 200 &ipstealth, 0, ""); 201 #endif 202 203 204 /* Firewall hooks */ 205 ip_fw_chk_t *ip_fw_chk_ptr; 206 int fw_enable = 1 ; 207 int fw_one_pass = 1; 208 209 /* Dummynet hooks */ 210 ip_dn_io_t *ip_dn_io_ptr; 211 212 213 /* 214 * XXX this is ugly -- the following two global variables are 215 * used to store packet state while it travels through the stack. 216 * Note that the code even makes assumptions on the size and 217 * alignment of fields inside struct ip_srcrt so e.g. adding some 218 * fields will break the code. This needs to be fixed. 219 * 220 * We need to save the IP options in case a protocol wants to respond 221 * to an incoming packet over the same route if the packet got here 222 * using IP source routing. This allows connection establishment and 223 * maintenance when the remote end is on a network that is not known 224 * to us. 225 */ 226 static int ip_nhops = 0; 227 static struct ip_srcrt { 228 struct in_addr dst; /* final destination */ 229 char nop; /* one NOP to align */ 230 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 231 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 232 } ip_srcrt; 233 234 static void save_rte(u_char *, struct in_addr); 235 static int ip_dooptions(struct mbuf *m, int, 236 struct sockaddr_in *next_hop); 237 static void ip_forward(struct mbuf *m, int srcrt, 238 struct sockaddr_in *next_hop); 239 static void ip_freef(struct ipqhead *, struct ipq *); 240 static struct mbuf *ip_reass(struct mbuf *, struct ipqhead *, 241 struct ipq *, u_int32_t *, u_int16_t *); 242 243 /* 244 * IP initialization: fill in IP protocol switch table. 245 * All protocols not implemented in kernel go to raw IP protocol handler. 246 */ 247 void 248 ip_init() 249 { 250 register struct protosw *pr; 251 register int i; 252 253 TAILQ_INIT(&in_ifaddrhead); 254 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 255 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 256 if (pr == 0) 257 panic("ip_init"); 258 for (i = 0; i < IPPROTO_MAX; i++) 259 ip_protox[i] = pr - inetsw; 260 for (pr = inetdomain.dom_protosw; 261 pr < inetdomain.dom_protoswNPROTOSW; pr++) 262 if (pr->pr_domain->dom_family == PF_INET && 263 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 264 ip_protox[pr->pr_protocol] = pr - inetsw; 265 266 IPQ_LOCK_INIT(); 267 for (i = 0; i < IPREASS_NHASH; i++) 268 TAILQ_INIT(&ipq[i]); 269 270 maxnipq = nmbclusters / 32; 271 maxfragsperpacket = 16; 272 273 #ifndef RANDOM_IP_ID 274 ip_id = time_second & 0xffff; 275 #endif 276 ipintrq.ifq_maxlen = ipqmaxlen; 277 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 278 netisr_register(NETISR_IP, ip_input, &ipintrq); 279 } 280 281 /* 282 * XXX watch out this one. It is perhaps used as a cache for 283 * the most recently used route ? it is cleared in in_addroute() 284 * when a new route is successfully created. 285 */ 286 struct route ipforward_rt; 287 288 /* 289 * Ip input routine. Checksum and byte swap header. If fragmented 290 * try to reassemble. Process options. Pass to next level. 291 */ 292 void 293 ip_input(struct mbuf *m) 294 { 295 struct ip *ip; 296 struct ipq *fp; 297 struct in_ifaddr *ia = NULL; 298 struct ifaddr *ifa; 299 int i, hlen, checkif; 300 u_short sum; 301 struct in_addr pkt_dst; 302 u_int32_t divert_info = 0; /* packet divert/tee info */ 303 struct ip_fw_args args; 304 #ifdef PFIL_HOOKS 305 struct packet_filter_hook *pfh; 306 struct mbuf *m0; 307 int rv; 308 #endif /* PFIL_HOOKS */ 309 #ifdef FAST_IPSEC 310 struct m_tag *mtag; 311 struct tdb_ident *tdbi; 312 struct secpolicy *sp; 313 int s, error; 314 #endif /* FAST_IPSEC */ 315 316 args.eh = NULL; 317 args.oif = NULL; 318 args.rule = NULL; 319 args.divert_rule = 0; /* divert cookie */ 320 args.next_hop = NULL; 321 322 /* Grab info from MT_TAG mbufs prepended to the chain. */ 323 for (; m && m->m_type == MT_TAG; m = m->m_next) { 324 switch(m->_m_tag_id) { 325 default: 326 printf("ip_input: unrecognised MT_TAG tag %d\n", 327 m->_m_tag_id); 328 break; 329 330 case PACKET_TAG_DUMMYNET: 331 args.rule = ((struct dn_pkt *)m)->rule; 332 break; 333 334 case PACKET_TAG_DIVERT: 335 args.divert_rule = (intptr_t)m->m_hdr.mh_data & 0xffff; 336 break; 337 338 case PACKET_TAG_IPFORWARD: 339 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 340 break; 341 } 342 } 343 344 M_ASSERTPKTHDR(m); 345 346 if (args.rule) { /* dummynet already filtered us */ 347 ip = mtod(m, struct ip *); 348 hlen = ip->ip_hl << 2; 349 goto iphack ; 350 } 351 352 ipstat.ips_total++; 353 354 if (m->m_pkthdr.len < sizeof(struct ip)) 355 goto tooshort; 356 357 if (m->m_len < sizeof (struct ip) && 358 (m = m_pullup(m, sizeof (struct ip))) == 0) { 359 ipstat.ips_toosmall++; 360 return; 361 } 362 ip = mtod(m, struct ip *); 363 364 if (ip->ip_v != IPVERSION) { 365 ipstat.ips_badvers++; 366 goto bad; 367 } 368 369 hlen = ip->ip_hl << 2; 370 if (hlen < sizeof(struct ip)) { /* minimum header length */ 371 ipstat.ips_badhlen++; 372 goto bad; 373 } 374 if (hlen > m->m_len) { 375 if ((m = m_pullup(m, hlen)) == 0) { 376 ipstat.ips_badhlen++; 377 return; 378 } 379 ip = mtod(m, struct ip *); 380 } 381 382 /* 127/8 must not appear on wire - RFC1122 */ 383 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 384 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 385 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 386 ipstat.ips_badaddr++; 387 goto bad; 388 } 389 } 390 391 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 392 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 393 } else { 394 if (hlen == sizeof(struct ip)) { 395 sum = in_cksum_hdr(ip); 396 } else { 397 sum = in_cksum(m, hlen); 398 } 399 } 400 if (sum) { 401 ipstat.ips_badsum++; 402 goto bad; 403 } 404 405 /* 406 * Convert fields to host representation. 407 */ 408 ip->ip_len = ntohs(ip->ip_len); 409 if (ip->ip_len < hlen) { 410 ipstat.ips_badlen++; 411 goto bad; 412 } 413 ip->ip_off = ntohs(ip->ip_off); 414 415 /* 416 * Check that the amount of data in the buffers 417 * is as at least much as the IP header would have us expect. 418 * Trim mbufs if longer than we expect. 419 * Drop packet if shorter than we expect. 420 */ 421 if (m->m_pkthdr.len < ip->ip_len) { 422 tooshort: 423 ipstat.ips_tooshort++; 424 goto bad; 425 } 426 if (m->m_pkthdr.len > ip->ip_len) { 427 if (m->m_len == m->m_pkthdr.len) { 428 m->m_len = ip->ip_len; 429 m->m_pkthdr.len = ip->ip_len; 430 } else 431 m_adj(m, ip->ip_len - m->m_pkthdr.len); 432 } 433 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 434 /* 435 * Bypass packet filtering for packets from a tunnel (gif). 436 */ 437 if (ipsec_gethist(m, NULL)) 438 goto pass; 439 #endif 440 #if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF) 441 /* 442 * Bypass packet filtering for packets from a tunnel (gif). 443 */ 444 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 445 goto pass; 446 #endif 447 448 /* 449 * IpHack's section. 450 * Right now when no processing on packet has done 451 * and it is still fresh out of network we do our black 452 * deals with it. 453 * - Firewall: deny/allow/divert 454 * - Xlate: translate packet's addr/port (NAT). 455 * - Pipe: pass pkt through dummynet. 456 * - Wrap: fake packet's addr/port <unimpl.> 457 * - Encapsulate: put it in another IP and send out. <unimp.> 458 */ 459 460 iphack: 461 462 #ifdef PFIL_HOOKS 463 /* 464 * Run through list of hooks for input packets. If there are any 465 * filters which require that additional packets in the flow are 466 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 467 * Note that filters must _never_ set this flag, as another filter 468 * in the list may have previously cleared it. 469 */ 470 m0 = m; 471 pfh = pfil_hook_get(PFIL_IN, &inetsw[ip_protox[IPPROTO_IP]].pr_pfh); 472 for (; pfh; pfh = TAILQ_NEXT(pfh, pfil_link)) 473 if (pfh->pfil_func) { 474 rv = pfh->pfil_func(ip, hlen, 475 m->m_pkthdr.rcvif, 0, &m0); 476 if (rv) 477 return; 478 m = m0; 479 if (m == NULL) 480 return; 481 ip = mtod(m, struct ip *); 482 } 483 #endif /* PFIL_HOOKS */ 484 485 if (fw_enable && IPFW_LOADED) { 486 /* 487 * If we've been forwarded from the output side, then 488 * skip the firewall a second time 489 */ 490 if (args.next_hop) 491 goto ours; 492 493 args.m = m; 494 i = ip_fw_chk_ptr(&args); 495 m = args.m; 496 497 if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 498 if (m) 499 m_freem(m); 500 return; 501 } 502 ip = mtod(m, struct ip *); /* just in case m changed */ 503 if (i == 0 && args.next_hop == NULL) /* common case */ 504 goto pass; 505 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) { 506 /* Send packet to the appropriate pipe */ 507 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 508 return; 509 } 510 #ifdef IPDIVERT 511 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 512 /* Divert or tee packet */ 513 divert_info = i; 514 goto ours; 515 } 516 #endif 517 if (i == 0 && args.next_hop != NULL) 518 goto pass; 519 /* 520 * if we get here, the packet must be dropped 521 */ 522 m_freem(m); 523 return; 524 } 525 pass: 526 527 /* 528 * Process options and, if not destined for us, 529 * ship it on. ip_dooptions returns 1 when an 530 * error was detected (causing an icmp message 531 * to be sent and the original packet to be freed). 532 */ 533 ip_nhops = 0; /* for source routed packets */ 534 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, args.next_hop)) 535 return; 536 537 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 538 * matter if it is destined to another node, or whether it is 539 * a multicast one, RSVP wants it! and prevents it from being forwarded 540 * anywhere else. Also checks if the rsvp daemon is running before 541 * grabbing the packet. 542 */ 543 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 544 goto ours; 545 546 /* 547 * Check our list of addresses, to see if the packet is for us. 548 * If we don't have any addresses, assume any unicast packet 549 * we receive might be for us (and let the upper layers deal 550 * with it). 551 */ 552 if (TAILQ_EMPTY(&in_ifaddrhead) && 553 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 554 goto ours; 555 556 /* 557 * Cache the destination address of the packet; this may be 558 * changed by use of 'ipfw fwd'. 559 */ 560 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 561 562 /* 563 * Enable a consistency check between the destination address 564 * and the arrival interface for a unicast packet (the RFC 1122 565 * strong ES model) if IP forwarding is disabled and the packet 566 * is not locally generated and the packet is not subject to 567 * 'ipfw fwd'. 568 * 569 * XXX - Checking also should be disabled if the destination 570 * address is ipnat'ed to a different interface. 571 * 572 * XXX - Checking is incompatible with IP aliases added 573 * to the loopback interface instead of the interface where 574 * the packets are received. 575 */ 576 checkif = ip_checkinterface && (ipforwarding == 0) && 577 m->m_pkthdr.rcvif != NULL && 578 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 579 (args.next_hop == NULL); 580 581 /* 582 * Check for exact addresses in the hash bucket. 583 */ 584 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 585 /* 586 * If the address matches, verify that the packet 587 * arrived via the correct interface if checking is 588 * enabled. 589 */ 590 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 591 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 592 goto ours; 593 } 594 /* 595 * Check for broadcast addresses. 596 * 597 * Only accept broadcast packets that arrive via the matching 598 * interface. Reception of forwarded directed broadcasts would 599 * be handled via ip_forward() and ether_output() with the loopback 600 * into the stack for SIMPLEX interfaces handled by ether_output(). 601 */ 602 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 603 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 604 if (ifa->ifa_addr->sa_family != AF_INET) 605 continue; 606 ia = ifatoia(ifa); 607 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 608 pkt_dst.s_addr) 609 goto ours; 610 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 611 goto ours; 612 #ifdef BOOTP_COMPAT 613 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 614 goto ours; 615 #endif 616 } 617 } 618 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 619 struct in_multi *inm; 620 if (ip_mrouter) { 621 /* 622 * If we are acting as a multicast router, all 623 * incoming multicast packets are passed to the 624 * kernel-level multicast forwarding function. 625 * The packet is returned (relatively) intact; if 626 * ip_mforward() returns a non-zero value, the packet 627 * must be discarded, else it may be accepted below. 628 */ 629 if (ip_mforward && 630 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 631 ipstat.ips_cantforward++; 632 m_freem(m); 633 return; 634 } 635 636 /* 637 * The process-level routing daemon needs to receive 638 * all multicast IGMP packets, whether or not this 639 * host belongs to their destination groups. 640 */ 641 if (ip->ip_p == IPPROTO_IGMP) 642 goto ours; 643 ipstat.ips_forward++; 644 } 645 /* 646 * See if we belong to the destination multicast group on the 647 * arrival interface. 648 */ 649 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 650 if (inm == NULL) { 651 ipstat.ips_notmember++; 652 m_freem(m); 653 return; 654 } 655 goto ours; 656 } 657 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 658 goto ours; 659 if (ip->ip_dst.s_addr == INADDR_ANY) 660 goto ours; 661 662 /* 663 * FAITH(Firewall Aided Internet Translator) 664 */ 665 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 666 if (ip_keepfaith) { 667 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 668 goto ours; 669 } 670 m_freem(m); 671 return; 672 } 673 674 /* 675 * Not for us; forward if possible and desirable. 676 */ 677 if (ipforwarding == 0) { 678 ipstat.ips_cantforward++; 679 m_freem(m); 680 } else { 681 #ifdef IPSEC 682 /* 683 * Enforce inbound IPsec SPD. 684 */ 685 if (ipsec4_in_reject(m, NULL)) { 686 ipsecstat.in_polvio++; 687 goto bad; 688 } 689 #endif /* IPSEC */ 690 #ifdef FAST_IPSEC 691 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 692 s = splnet(); 693 if (mtag != NULL) { 694 tdbi = (struct tdb_ident *)(mtag + 1); 695 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 696 } else { 697 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 698 IP_FORWARDING, &error); 699 } 700 if (sp == NULL) { /* NB: can happen if error */ 701 splx(s); 702 /*XXX error stat???*/ 703 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 704 goto bad; 705 } 706 707 /* 708 * Check security policy against packet attributes. 709 */ 710 error = ipsec_in_reject(sp, m); 711 KEY_FREESP(&sp); 712 splx(s); 713 if (error) { 714 ipstat.ips_cantforward++; 715 goto bad; 716 } 717 #endif /* FAST_IPSEC */ 718 ip_forward(m, 0, args.next_hop); 719 } 720 return; 721 722 ours: 723 #ifdef IPSTEALTH 724 /* 725 * IPSTEALTH: Process non-routing options only 726 * if the packet is destined for us. 727 */ 728 if (ipstealth && hlen > sizeof (struct ip) && 729 ip_dooptions(m, 1, args.next_hop)) 730 return; 731 #endif /* IPSTEALTH */ 732 733 /* Count the packet in the ip address stats */ 734 if (ia != NULL) { 735 ia->ia_ifa.if_ipackets++; 736 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 737 } 738 739 /* 740 * If offset or IP_MF are set, must reassemble. 741 * Otherwise, nothing need be done. 742 * (We could look in the reassembly queue to see 743 * if the packet was previously fragmented, 744 * but it's not worth the time; just let them time out.) 745 */ 746 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 747 748 /* If maxnipq is 0, never accept fragments. */ 749 if (maxnipq == 0) { 750 ipstat.ips_fragments++; 751 ipstat.ips_fragdropped++; 752 goto bad; 753 } 754 755 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 756 IPQ_LOCK(); 757 /* 758 * Look for queue of fragments 759 * of this datagram. 760 */ 761 TAILQ_FOREACH(fp, &ipq[sum], ipq_list) 762 if (ip->ip_id == fp->ipq_id && 763 ip->ip_src.s_addr == fp->ipq_src.s_addr && 764 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 765 #ifdef MAC 766 mac_fragment_match(m, fp) && 767 #endif 768 ip->ip_p == fp->ipq_p) 769 goto found; 770 771 fp = NULL; 772 773 /* 774 * Enforce upper bound on number of fragmented packets 775 * for which we attempt reassembly; 776 * If maxnipq is -1, accept all fragments without limitation. 777 */ 778 if ((nipq > maxnipq) && (maxnipq > 0)) { 779 /* 780 * drop something from the tail of the current queue 781 * before proceeding further 782 */ 783 struct ipq *q = TAILQ_LAST(&ipq[sum], ipqhead); 784 if (q == NULL) { /* gak */ 785 for (i = 0; i < IPREASS_NHASH; i++) { 786 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 787 if (r) { 788 ipstat.ips_fragtimeout += r->ipq_nfrags; 789 ip_freef(&ipq[i], r); 790 break; 791 } 792 } 793 } else { 794 ipstat.ips_fragtimeout += q->ipq_nfrags; 795 ip_freef(&ipq[sum], q); 796 } 797 } 798 found: 799 /* 800 * Adjust ip_len to not reflect header, 801 * convert offset of this to bytes. 802 */ 803 ip->ip_len -= hlen; 804 if (ip->ip_off & IP_MF) { 805 /* 806 * Make sure that fragments have a data length 807 * that's a non-zero multiple of 8 bytes. 808 */ 809 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 810 IPQ_UNLOCK(); 811 ipstat.ips_toosmall++; /* XXX */ 812 goto bad; 813 } 814 m->m_flags |= M_FRAG; 815 } else 816 m->m_flags &= ~M_FRAG; 817 ip->ip_off <<= 3; 818 819 /* 820 * Attempt reassembly; if it succeeds, proceed. 821 * ip_reass() will return a different mbuf, and update 822 * the divert info in divert_info and args.divert_rule. 823 */ 824 ipstat.ips_fragments++; 825 m->m_pkthdr.header = ip; 826 m = ip_reass(m, 827 &ipq[sum], fp, &divert_info, &args.divert_rule); 828 IPQ_UNLOCK(); 829 if (m == 0) 830 return; 831 ipstat.ips_reassembled++; 832 ip = mtod(m, struct ip *); 833 /* Get the header length of the reassembled packet */ 834 hlen = ip->ip_hl << 2; 835 #ifdef IPDIVERT 836 /* Restore original checksum before diverting packet */ 837 if (divert_info != 0) { 838 ip->ip_len += hlen; 839 ip->ip_len = htons(ip->ip_len); 840 ip->ip_off = htons(ip->ip_off); 841 ip->ip_sum = 0; 842 if (hlen == sizeof(struct ip)) 843 ip->ip_sum = in_cksum_hdr(ip); 844 else 845 ip->ip_sum = in_cksum(m, hlen); 846 ip->ip_off = ntohs(ip->ip_off); 847 ip->ip_len = ntohs(ip->ip_len); 848 ip->ip_len -= hlen; 849 } 850 #endif 851 } else 852 ip->ip_len -= hlen; 853 854 #ifdef IPDIVERT 855 /* 856 * Divert or tee packet to the divert protocol if required. 857 */ 858 if (divert_info != 0) { 859 struct mbuf *clone = NULL; 860 861 /* Clone packet if we're doing a 'tee' */ 862 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 863 clone = m_dup(m, M_DONTWAIT); 864 865 /* Restore packet header fields to original values */ 866 ip->ip_len += hlen; 867 ip->ip_len = htons(ip->ip_len); 868 ip->ip_off = htons(ip->ip_off); 869 870 /* Deliver packet to divert input routine */ 871 divert_packet(m, 1, divert_info & 0xffff, args.divert_rule); 872 ipstat.ips_delivered++; 873 874 /* If 'tee', continue with original packet */ 875 if (clone == NULL) 876 return; 877 m = clone; 878 ip = mtod(m, struct ip *); 879 ip->ip_len += hlen; 880 /* 881 * Jump backwards to complete processing of the 882 * packet. But first clear divert_info to avoid 883 * entering this block again. 884 * We do not need to clear args.divert_rule 885 * or args.next_hop as they will not be used. 886 */ 887 divert_info = 0; 888 goto pass; 889 } 890 #endif 891 892 #ifdef IPSEC 893 /* 894 * enforce IPsec policy checking if we are seeing last header. 895 * note that we do not visit this with protocols with pcb layer 896 * code - like udp/tcp/raw ip. 897 */ 898 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 899 ipsec4_in_reject(m, NULL)) { 900 ipsecstat.in_polvio++; 901 goto bad; 902 } 903 #endif 904 #if FAST_IPSEC 905 /* 906 * enforce IPsec policy checking if we are seeing last header. 907 * note that we do not visit this with protocols with pcb layer 908 * code - like udp/tcp/raw ip. 909 */ 910 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 911 /* 912 * Check if the packet has already had IPsec processing 913 * done. If so, then just pass it along. This tag gets 914 * set during AH, ESP, etc. input handling, before the 915 * packet is returned to the ip input queue for delivery. 916 */ 917 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 918 s = splnet(); 919 if (mtag != NULL) { 920 tdbi = (struct tdb_ident *)(mtag + 1); 921 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 922 } else { 923 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 924 IP_FORWARDING, &error); 925 } 926 if (sp != NULL) { 927 /* 928 * Check security policy against packet attributes. 929 */ 930 error = ipsec_in_reject(sp, m); 931 KEY_FREESP(&sp); 932 } else { 933 /* XXX error stat??? */ 934 error = EINVAL; 935 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 936 goto bad; 937 } 938 splx(s); 939 if (error) 940 goto bad; 941 } 942 #endif /* FAST_IPSEC */ 943 944 /* 945 * Switch out to protocol's input routine. 946 */ 947 ipstat.ips_delivered++; 948 if (args.next_hop && ip->ip_p == IPPROTO_TCP) { 949 /* TCP needs IPFORWARD info if available */ 950 struct m_hdr tag; 951 952 tag.mh_type = MT_TAG; 953 tag.mh_flags = PACKET_TAG_IPFORWARD; 954 tag.mh_data = (caddr_t)args.next_hop; 955 tag.mh_next = m; 956 957 (*inetsw[ip_protox[ip->ip_p]].pr_input)( 958 (struct mbuf *)&tag, hlen); 959 } else 960 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 961 return; 962 bad: 963 m_freem(m); 964 } 965 966 /* 967 * Take incoming datagram fragment and try to reassemble it into 968 * whole datagram. If a chain for reassembly of this datagram already 969 * exists, then it is given as fp; otherwise have to make a chain. 970 * 971 * When IPDIVERT enabled, keep additional state with each packet that 972 * tells us if we need to divert or tee the packet we're building. 973 * In particular, *divinfo includes the port and TEE flag, 974 * *divert_rule is the number of the matching rule. 975 */ 976 977 static struct mbuf * 978 ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp, 979 u_int32_t *divinfo, u_int16_t *divert_rule) 980 { 981 struct ip *ip = mtod(m, struct ip *); 982 register struct mbuf *p, *q, *nq; 983 struct mbuf *t; 984 int hlen = ip->ip_hl << 2; 985 int i, next; 986 987 IPQ_LOCK_ASSERT(); 988 989 /* 990 * Presence of header sizes in mbufs 991 * would confuse code below. 992 */ 993 m->m_data += hlen; 994 m->m_len -= hlen; 995 996 /* 997 * If first fragment to arrive, create a reassembly queue. 998 */ 999 if (fp == NULL) { 1000 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 1001 goto dropfrag; 1002 fp = mtod(t, struct ipq *); 1003 #ifdef MAC 1004 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 1005 m_free(t); 1006 goto dropfrag; 1007 } 1008 mac_create_ipq(m, fp); 1009 #endif 1010 TAILQ_INSERT_HEAD(head, fp, ipq_list); 1011 nipq++; 1012 fp->ipq_nfrags = 1; 1013 fp->ipq_ttl = IPFRAGTTL; 1014 fp->ipq_p = ip->ip_p; 1015 fp->ipq_id = ip->ip_id; 1016 fp->ipq_src = ip->ip_src; 1017 fp->ipq_dst = ip->ip_dst; 1018 fp->ipq_frags = m; 1019 m->m_nextpkt = NULL; 1020 #ifdef IPDIVERT 1021 fp->ipq_div_info = 0; 1022 fp->ipq_div_cookie = 0; 1023 #endif 1024 goto inserted; 1025 } else { 1026 fp->ipq_nfrags++; 1027 #ifdef MAC 1028 mac_update_ipq(m, fp); 1029 #endif 1030 } 1031 1032 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1033 1034 /* 1035 * Find a segment which begins after this one does. 1036 */ 1037 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1038 if (GETIP(q)->ip_off > ip->ip_off) 1039 break; 1040 1041 /* 1042 * If there is a preceding segment, it may provide some of 1043 * our data already. If so, drop the data from the incoming 1044 * segment. If it provides all of our data, drop us, otherwise 1045 * stick new segment in the proper place. 1046 * 1047 * If some of the data is dropped from the the preceding 1048 * segment, then it's checksum is invalidated. 1049 */ 1050 if (p) { 1051 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1052 if (i > 0) { 1053 if (i >= ip->ip_len) 1054 goto dropfrag; 1055 m_adj(m, i); 1056 m->m_pkthdr.csum_flags = 0; 1057 ip->ip_off += i; 1058 ip->ip_len -= i; 1059 } 1060 m->m_nextpkt = p->m_nextpkt; 1061 p->m_nextpkt = m; 1062 } else { 1063 m->m_nextpkt = fp->ipq_frags; 1064 fp->ipq_frags = m; 1065 } 1066 1067 /* 1068 * While we overlap succeeding segments trim them or, 1069 * if they are completely covered, dequeue them. 1070 */ 1071 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1072 q = nq) { 1073 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1074 if (i < GETIP(q)->ip_len) { 1075 GETIP(q)->ip_len -= i; 1076 GETIP(q)->ip_off += i; 1077 m_adj(q, i); 1078 q->m_pkthdr.csum_flags = 0; 1079 break; 1080 } 1081 nq = q->m_nextpkt; 1082 m->m_nextpkt = nq; 1083 ipstat.ips_fragdropped++; 1084 fp->ipq_nfrags--; 1085 m_freem(q); 1086 } 1087 1088 inserted: 1089 1090 #ifdef IPDIVERT 1091 /* 1092 * Transfer firewall instructions to the fragment structure. 1093 * Only trust info in the fragment at offset 0. 1094 */ 1095 if (ip->ip_off == 0) { 1096 fp->ipq_div_info = *divinfo; 1097 fp->ipq_div_cookie = *divert_rule; 1098 } 1099 *divinfo = 0; 1100 *divert_rule = 0; 1101 #endif 1102 1103 /* 1104 * Check for complete reassembly and perform frag per packet 1105 * limiting. 1106 * 1107 * Frag limiting is performed here so that the nth frag has 1108 * a chance to complete the packet before we drop the packet. 1109 * As a result, n+1 frags are actually allowed per packet, but 1110 * only n will ever be stored. (n = maxfragsperpacket.) 1111 * 1112 */ 1113 next = 0; 1114 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1115 if (GETIP(q)->ip_off != next) { 1116 if (fp->ipq_nfrags > maxfragsperpacket) { 1117 ipstat.ips_fragdropped += fp->ipq_nfrags; 1118 ip_freef(head, fp); 1119 } 1120 return (0); 1121 } 1122 next += GETIP(q)->ip_len; 1123 } 1124 /* Make sure the last packet didn't have the IP_MF flag */ 1125 if (p->m_flags & M_FRAG) { 1126 if (fp->ipq_nfrags > maxfragsperpacket) { 1127 ipstat.ips_fragdropped += fp->ipq_nfrags; 1128 ip_freef(head, fp); 1129 } 1130 return (0); 1131 } 1132 1133 /* 1134 * Reassembly is complete. Make sure the packet is a sane size. 1135 */ 1136 q = fp->ipq_frags; 1137 ip = GETIP(q); 1138 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1139 ipstat.ips_toolong++; 1140 ipstat.ips_fragdropped += fp->ipq_nfrags; 1141 ip_freef(head, fp); 1142 return (0); 1143 } 1144 1145 /* 1146 * Concatenate fragments. 1147 */ 1148 m = q; 1149 t = m->m_next; 1150 m->m_next = 0; 1151 m_cat(m, t); 1152 nq = q->m_nextpkt; 1153 q->m_nextpkt = 0; 1154 for (q = nq; q != NULL; q = nq) { 1155 nq = q->m_nextpkt; 1156 q->m_nextpkt = NULL; 1157 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1158 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1159 m_cat(m, q); 1160 } 1161 #ifdef MAC 1162 mac_create_datagram_from_ipq(fp, m); 1163 mac_destroy_ipq(fp); 1164 #endif 1165 1166 #ifdef IPDIVERT 1167 /* 1168 * Extract firewall instructions from the fragment structure. 1169 */ 1170 *divinfo = fp->ipq_div_info; 1171 *divert_rule = fp->ipq_div_cookie; 1172 #endif 1173 1174 /* 1175 * Create header for new ip packet by 1176 * modifying header of first packet; 1177 * dequeue and discard fragment reassembly header. 1178 * Make header visible. 1179 */ 1180 ip->ip_len = next; 1181 ip->ip_src = fp->ipq_src; 1182 ip->ip_dst = fp->ipq_dst; 1183 TAILQ_REMOVE(head, fp, ipq_list); 1184 nipq--; 1185 (void) m_free(dtom(fp)); 1186 m->m_len += (ip->ip_hl << 2); 1187 m->m_data -= (ip->ip_hl << 2); 1188 /* some debugging cruft by sklower, below, will go away soon */ 1189 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1190 m_fixhdr(m); 1191 return (m); 1192 1193 dropfrag: 1194 #ifdef IPDIVERT 1195 *divinfo = 0; 1196 *divert_rule = 0; 1197 #endif 1198 ipstat.ips_fragdropped++; 1199 if (fp != NULL) 1200 fp->ipq_nfrags--; 1201 m_freem(m); 1202 return (0); 1203 1204 #undef GETIP 1205 } 1206 1207 /* 1208 * Free a fragment reassembly header and all 1209 * associated datagrams. 1210 */ 1211 static void 1212 ip_freef(fhp, fp) 1213 struct ipqhead *fhp; 1214 struct ipq *fp; 1215 { 1216 register struct mbuf *q; 1217 1218 IPQ_LOCK_ASSERT(); 1219 1220 while (fp->ipq_frags) { 1221 q = fp->ipq_frags; 1222 fp->ipq_frags = q->m_nextpkt; 1223 m_freem(q); 1224 } 1225 TAILQ_REMOVE(fhp, fp, ipq_list); 1226 (void) m_free(dtom(fp)); 1227 nipq--; 1228 } 1229 1230 /* 1231 * IP timer processing; 1232 * if a timer expires on a reassembly 1233 * queue, discard it. 1234 */ 1235 void 1236 ip_slowtimo() 1237 { 1238 register struct ipq *fp; 1239 int s = splnet(); 1240 int i; 1241 1242 IPQ_LOCK(); 1243 for (i = 0; i < IPREASS_NHASH; i++) { 1244 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1245 struct ipq *fpp; 1246 1247 fpp = fp; 1248 fp = TAILQ_NEXT(fp, ipq_list); 1249 if(--fpp->ipq_ttl == 0) { 1250 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1251 ip_freef(&ipq[i], fpp); 1252 } 1253 } 1254 } 1255 /* 1256 * If we are over the maximum number of fragments 1257 * (due to the limit being lowered), drain off 1258 * enough to get down to the new limit. 1259 */ 1260 if (maxnipq >= 0 && nipq > maxnipq) { 1261 for (i = 0; i < IPREASS_NHASH; i++) { 1262 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1263 ipstat.ips_fragdropped += 1264 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1265 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1266 } 1267 } 1268 } 1269 IPQ_UNLOCK(); 1270 ipflow_slowtimo(); 1271 splx(s); 1272 } 1273 1274 /* 1275 * Drain off all datagram fragments. 1276 */ 1277 void 1278 ip_drain() 1279 { 1280 int i; 1281 1282 IPQ_LOCK(); 1283 for (i = 0; i < IPREASS_NHASH; i++) { 1284 while(!TAILQ_EMPTY(&ipq[i])) { 1285 ipstat.ips_fragdropped += 1286 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1287 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1288 } 1289 } 1290 IPQ_UNLOCK(); 1291 in_rtqdrain(); 1292 } 1293 1294 /* 1295 * Do option processing on a datagram, 1296 * possibly discarding it if bad options are encountered, 1297 * or forwarding it if source-routed. 1298 * The pass argument is used when operating in the IPSTEALTH 1299 * mode to tell what options to process: 1300 * [LS]SRR (pass 0) or the others (pass 1). 1301 * The reason for as many as two passes is that when doing IPSTEALTH, 1302 * non-routing options should be processed only if the packet is for us. 1303 * Returns 1 if packet has been forwarded/freed, 1304 * 0 if the packet should be processed further. 1305 */ 1306 static int 1307 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1308 { 1309 struct ip *ip = mtod(m, struct ip *); 1310 u_char *cp; 1311 struct in_ifaddr *ia; 1312 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1313 struct in_addr *sin, dst; 1314 n_time ntime; 1315 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 1316 1317 dst = ip->ip_dst; 1318 cp = (u_char *)(ip + 1); 1319 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1320 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1321 opt = cp[IPOPT_OPTVAL]; 1322 if (opt == IPOPT_EOL) 1323 break; 1324 if (opt == IPOPT_NOP) 1325 optlen = 1; 1326 else { 1327 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1328 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1329 goto bad; 1330 } 1331 optlen = cp[IPOPT_OLEN]; 1332 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1333 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1334 goto bad; 1335 } 1336 } 1337 switch (opt) { 1338 1339 default: 1340 break; 1341 1342 /* 1343 * Source routing with record. 1344 * Find interface with current destination address. 1345 * If none on this machine then drop if strictly routed, 1346 * or do nothing if loosely routed. 1347 * Record interface address and bring up next address 1348 * component. If strictly routed make sure next 1349 * address is on directly accessible net. 1350 */ 1351 case IPOPT_LSRR: 1352 case IPOPT_SSRR: 1353 #ifdef IPSTEALTH 1354 if (ipstealth && pass > 0) 1355 break; 1356 #endif 1357 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1358 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1359 goto bad; 1360 } 1361 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1362 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1363 goto bad; 1364 } 1365 ipaddr.sin_addr = ip->ip_dst; 1366 ia = (struct in_ifaddr *) 1367 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1368 if (ia == 0) { 1369 if (opt == IPOPT_SSRR) { 1370 type = ICMP_UNREACH; 1371 code = ICMP_UNREACH_SRCFAIL; 1372 goto bad; 1373 } 1374 if (!ip_dosourceroute) 1375 goto nosourcerouting; 1376 /* 1377 * Loose routing, and not at next destination 1378 * yet; nothing to do except forward. 1379 */ 1380 break; 1381 } 1382 off--; /* 0 origin */ 1383 if (off > optlen - (int)sizeof(struct in_addr)) { 1384 /* 1385 * End of source route. Should be for us. 1386 */ 1387 if (!ip_acceptsourceroute) 1388 goto nosourcerouting; 1389 save_rte(cp, ip->ip_src); 1390 break; 1391 } 1392 #ifdef IPSTEALTH 1393 if (ipstealth) 1394 goto dropit; 1395 #endif 1396 if (!ip_dosourceroute) { 1397 if (ipforwarding) { 1398 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1399 /* 1400 * Acting as a router, so generate ICMP 1401 */ 1402 nosourcerouting: 1403 strcpy(buf, inet_ntoa(ip->ip_dst)); 1404 log(LOG_WARNING, 1405 "attempted source route from %s to %s\n", 1406 inet_ntoa(ip->ip_src), buf); 1407 type = ICMP_UNREACH; 1408 code = ICMP_UNREACH_SRCFAIL; 1409 goto bad; 1410 } else { 1411 /* 1412 * Not acting as a router, so silently drop. 1413 */ 1414 #ifdef IPSTEALTH 1415 dropit: 1416 #endif 1417 ipstat.ips_cantforward++; 1418 m_freem(m); 1419 return (1); 1420 } 1421 } 1422 1423 /* 1424 * locate outgoing interface 1425 */ 1426 (void)memcpy(&ipaddr.sin_addr, cp + off, 1427 sizeof(ipaddr.sin_addr)); 1428 1429 if (opt == IPOPT_SSRR) { 1430 #define INA struct in_ifaddr * 1431 #define SA struct sockaddr * 1432 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1433 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1434 } else 1435 ia = ip_rtaddr(ipaddr.sin_addr, &ipforward_rt); 1436 if (ia == 0) { 1437 type = ICMP_UNREACH; 1438 code = ICMP_UNREACH_SRCFAIL; 1439 goto bad; 1440 } 1441 ip->ip_dst = ipaddr.sin_addr; 1442 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1443 sizeof(struct in_addr)); 1444 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1445 /* 1446 * Let ip_intr's mcast routing check handle mcast pkts 1447 */ 1448 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1449 break; 1450 1451 case IPOPT_RR: 1452 #ifdef IPSTEALTH 1453 if (ipstealth && pass == 0) 1454 break; 1455 #endif 1456 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1457 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1458 goto bad; 1459 } 1460 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1461 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1462 goto bad; 1463 } 1464 /* 1465 * If no space remains, ignore. 1466 */ 1467 off--; /* 0 origin */ 1468 if (off > optlen - (int)sizeof(struct in_addr)) 1469 break; 1470 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1471 sizeof(ipaddr.sin_addr)); 1472 /* 1473 * locate outgoing interface; if we're the destination, 1474 * use the incoming interface (should be same). 1475 */ 1476 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1477 (ia = ip_rtaddr(ipaddr.sin_addr, 1478 &ipforward_rt)) == 0) { 1479 type = ICMP_UNREACH; 1480 code = ICMP_UNREACH_HOST; 1481 goto bad; 1482 } 1483 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1484 sizeof(struct in_addr)); 1485 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1486 break; 1487 1488 case IPOPT_TS: 1489 #ifdef IPSTEALTH 1490 if (ipstealth && pass == 0) 1491 break; 1492 #endif 1493 code = cp - (u_char *)ip; 1494 if (optlen < 4 || optlen > 40) { 1495 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1496 goto bad; 1497 } 1498 if ((off = cp[IPOPT_OFFSET]) < 5) { 1499 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1500 goto bad; 1501 } 1502 if (off > optlen - (int)sizeof(int32_t)) { 1503 cp[IPOPT_OFFSET + 1] += (1 << 4); 1504 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1505 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1506 goto bad; 1507 } 1508 break; 1509 } 1510 off--; /* 0 origin */ 1511 sin = (struct in_addr *)(cp + off); 1512 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1513 1514 case IPOPT_TS_TSONLY: 1515 break; 1516 1517 case IPOPT_TS_TSANDADDR: 1518 if (off + sizeof(n_time) + 1519 sizeof(struct in_addr) > optlen) { 1520 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1521 goto bad; 1522 } 1523 ipaddr.sin_addr = dst; 1524 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1525 m->m_pkthdr.rcvif); 1526 if (ia == 0) 1527 continue; 1528 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1529 sizeof(struct in_addr)); 1530 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1531 off += sizeof(struct in_addr); 1532 break; 1533 1534 case IPOPT_TS_PRESPEC: 1535 if (off + sizeof(n_time) + 1536 sizeof(struct in_addr) > optlen) { 1537 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1538 goto bad; 1539 } 1540 (void)memcpy(&ipaddr.sin_addr, sin, 1541 sizeof(struct in_addr)); 1542 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1543 continue; 1544 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1545 off += sizeof(struct in_addr); 1546 break; 1547 1548 default: 1549 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1550 goto bad; 1551 } 1552 ntime = iptime(); 1553 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1554 cp[IPOPT_OFFSET] += sizeof(n_time); 1555 } 1556 } 1557 if (forward && ipforwarding) { 1558 ip_forward(m, 1, next_hop); 1559 return (1); 1560 } 1561 return (0); 1562 bad: 1563 icmp_error(m, type, code, 0, 0); 1564 ipstat.ips_badoptions++; 1565 return (1); 1566 } 1567 1568 /* 1569 * Given address of next destination (final or next hop), 1570 * return internet address info of interface to be used to get there. 1571 */ 1572 struct in_ifaddr * 1573 ip_rtaddr(dst, rt) 1574 struct in_addr dst; 1575 struct route *rt; 1576 { 1577 register struct sockaddr_in *sin; 1578 1579 sin = (struct sockaddr_in *)&rt->ro_dst; 1580 1581 if (rt->ro_rt == 0 || 1582 !(rt->ro_rt->rt_flags & RTF_UP) || 1583 dst.s_addr != sin->sin_addr.s_addr) { 1584 if (rt->ro_rt) { 1585 RTFREE(rt->ro_rt); 1586 rt->ro_rt = 0; 1587 } 1588 sin->sin_family = AF_INET; 1589 sin->sin_len = sizeof(*sin); 1590 sin->sin_addr = dst; 1591 1592 rtalloc_ign(rt, RTF_PRCLONING); 1593 } 1594 if (rt->ro_rt == 0) 1595 return ((struct in_ifaddr *)0); 1596 return (ifatoia(rt->ro_rt->rt_ifa)); 1597 } 1598 1599 /* 1600 * Save incoming source route for use in replies, 1601 * to be picked up later by ip_srcroute if the receiver is interested. 1602 */ 1603 static void 1604 save_rte(option, dst) 1605 u_char *option; 1606 struct in_addr dst; 1607 { 1608 unsigned olen; 1609 1610 olen = option[IPOPT_OLEN]; 1611 #ifdef DIAGNOSTIC 1612 if (ipprintfs) 1613 printf("save_rte: olen %d\n", olen); 1614 #endif 1615 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1616 return; 1617 bcopy(option, ip_srcrt.srcopt, olen); 1618 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1619 ip_srcrt.dst = dst; 1620 } 1621 1622 /* 1623 * Retrieve incoming source route for use in replies, 1624 * in the same form used by setsockopt. 1625 * The first hop is placed before the options, will be removed later. 1626 */ 1627 struct mbuf * 1628 ip_srcroute() 1629 { 1630 register struct in_addr *p, *q; 1631 register struct mbuf *m; 1632 1633 if (ip_nhops == 0) 1634 return ((struct mbuf *)0); 1635 m = m_get(M_DONTWAIT, MT_HEADER); 1636 if (m == 0) 1637 return ((struct mbuf *)0); 1638 1639 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1640 1641 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1642 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1643 OPTSIZ; 1644 #ifdef DIAGNOSTIC 1645 if (ipprintfs) 1646 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1647 #endif 1648 1649 /* 1650 * First save first hop for return route 1651 */ 1652 p = &ip_srcrt.route[ip_nhops - 1]; 1653 *(mtod(m, struct in_addr *)) = *p--; 1654 #ifdef DIAGNOSTIC 1655 if (ipprintfs) 1656 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1657 #endif 1658 1659 /* 1660 * Copy option fields and padding (nop) to mbuf. 1661 */ 1662 ip_srcrt.nop = IPOPT_NOP; 1663 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1664 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1665 &ip_srcrt.nop, OPTSIZ); 1666 q = (struct in_addr *)(mtod(m, caddr_t) + 1667 sizeof(struct in_addr) + OPTSIZ); 1668 #undef OPTSIZ 1669 /* 1670 * Record return path as an IP source route, 1671 * reversing the path (pointers are now aligned). 1672 */ 1673 while (p >= ip_srcrt.route) { 1674 #ifdef DIAGNOSTIC 1675 if (ipprintfs) 1676 printf(" %lx", (u_long)ntohl(q->s_addr)); 1677 #endif 1678 *q++ = *p--; 1679 } 1680 /* 1681 * Last hop goes to final destination. 1682 */ 1683 *q = ip_srcrt.dst; 1684 #ifdef DIAGNOSTIC 1685 if (ipprintfs) 1686 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1687 #endif 1688 return (m); 1689 } 1690 1691 /* 1692 * Strip out IP options, at higher 1693 * level protocol in the kernel. 1694 * Second argument is buffer to which options 1695 * will be moved, and return value is their length. 1696 * XXX should be deleted; last arg currently ignored. 1697 */ 1698 void 1699 ip_stripoptions(m, mopt) 1700 register struct mbuf *m; 1701 struct mbuf *mopt; 1702 { 1703 register int i; 1704 struct ip *ip = mtod(m, struct ip *); 1705 register caddr_t opts; 1706 int olen; 1707 1708 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1709 opts = (caddr_t)(ip + 1); 1710 i = m->m_len - (sizeof (struct ip) + olen); 1711 bcopy(opts + olen, opts, (unsigned)i); 1712 m->m_len -= olen; 1713 if (m->m_flags & M_PKTHDR) 1714 m->m_pkthdr.len -= olen; 1715 ip->ip_v = IPVERSION; 1716 ip->ip_hl = sizeof(struct ip) >> 2; 1717 } 1718 1719 u_char inetctlerrmap[PRC_NCMDS] = { 1720 0, 0, 0, 0, 1721 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1722 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1723 EMSGSIZE, EHOSTUNREACH, 0, 0, 1724 0, 0, EHOSTUNREACH, 0, 1725 ENOPROTOOPT, ECONNREFUSED 1726 }; 1727 1728 /* 1729 * Forward a packet. If some error occurs return the sender 1730 * an icmp packet. Note we can't always generate a meaningful 1731 * icmp message because icmp doesn't have a large enough repertoire 1732 * of codes and types. 1733 * 1734 * If not forwarding, just drop the packet. This could be confusing 1735 * if ipforwarding was zero but some routing protocol was advancing 1736 * us as a gateway to somewhere. However, we must let the routing 1737 * protocol deal with that. 1738 * 1739 * The srcrt parameter indicates whether the packet is being forwarded 1740 * via a source route. 1741 */ 1742 static void 1743 ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop) 1744 { 1745 struct ip *ip = mtod(m, struct ip *); 1746 struct rtentry *rt; 1747 int error, type = 0, code = 0; 1748 struct mbuf *mcopy; 1749 n_long dest; 1750 struct in_addr pkt_dst; 1751 struct ifnet *destifp; 1752 #if defined(IPSEC) || defined(FAST_IPSEC) 1753 struct ifnet dummyifp; 1754 #endif 1755 1756 dest = 0; 1757 /* 1758 * Cache the destination address of the packet; this may be 1759 * changed by use of 'ipfw fwd'. 1760 */ 1761 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 1762 1763 #ifdef DIAGNOSTIC 1764 if (ipprintfs) 1765 printf("forward: src %lx dst %lx ttl %x\n", 1766 (u_long)ip->ip_src.s_addr, (u_long)pkt_dst.s_addr, 1767 ip->ip_ttl); 1768 #endif 1769 1770 1771 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(pkt_dst) == 0) { 1772 ipstat.ips_cantforward++; 1773 m_freem(m); 1774 return; 1775 } 1776 #ifdef IPSTEALTH 1777 if (!ipstealth) { 1778 #endif 1779 if (ip->ip_ttl <= IPTTLDEC) { 1780 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1781 dest, 0); 1782 return; 1783 } 1784 #ifdef IPSTEALTH 1785 } 1786 #endif 1787 1788 if (ip_rtaddr(pkt_dst, &ipforward_rt) == 0) { 1789 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1790 return; 1791 } else 1792 rt = ipforward_rt.ro_rt; 1793 1794 /* 1795 * Save the IP header and at most 8 bytes of the payload, 1796 * in case we need to generate an ICMP message to the src. 1797 * 1798 * XXX this can be optimized a lot by saving the data in a local 1799 * buffer on the stack (72 bytes at most), and only allocating the 1800 * mbuf if really necessary. The vast majority of the packets 1801 * are forwarded without having to send an ICMP back (either 1802 * because unnecessary, or because rate limited), so we are 1803 * really we are wasting a lot of work here. 1804 * 1805 * We don't use m_copy() because it might return a reference 1806 * to a shared cluster. Both this function and ip_output() 1807 * assume exclusive access to the IP header in `m', so any 1808 * data in a cluster may change before we reach icmp_error(). 1809 */ 1810 MGET(mcopy, M_DONTWAIT, m->m_type); 1811 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1812 /* 1813 * It's probably ok if the pkthdr dup fails (because 1814 * the deep copy of the tag chain failed), but for now 1815 * be conservative and just discard the copy since 1816 * code below may some day want the tags. 1817 */ 1818 m_free(mcopy); 1819 mcopy = NULL; 1820 } 1821 if (mcopy != NULL) { 1822 mcopy->m_len = imin((ip->ip_hl << 2) + 8, 1823 (int)ip->ip_len); 1824 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1825 /* 1826 * XXXMAC: Eventually, we may have an explict labeling 1827 * point here. 1828 */ 1829 } 1830 1831 #ifdef IPSTEALTH 1832 if (!ipstealth) { 1833 #endif 1834 ip->ip_ttl -= IPTTLDEC; 1835 #ifdef IPSTEALTH 1836 } 1837 #endif 1838 1839 /* 1840 * If forwarding packet using same interface that it came in on, 1841 * perhaps should send a redirect to sender to shortcut a hop. 1842 * Only send redirect if source is sending directly to us, 1843 * and if packet was not source routed (or has any options). 1844 * Also, don't send redirect if forwarding using a default route 1845 * or a route modified by a redirect. 1846 */ 1847 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1848 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1849 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1850 ipsendredirects && !srcrt && !next_hop) { 1851 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1852 u_long src = ntohl(ip->ip_src.s_addr); 1853 1854 if (RTA(rt) && 1855 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1856 if (rt->rt_flags & RTF_GATEWAY) 1857 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1858 else 1859 dest = pkt_dst.s_addr; 1860 /* Router requirements says to only send host redirects */ 1861 type = ICMP_REDIRECT; 1862 code = ICMP_REDIRECT_HOST; 1863 #ifdef DIAGNOSTIC 1864 if (ipprintfs) 1865 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1866 #endif 1867 } 1868 } 1869 1870 { 1871 struct m_hdr tag; 1872 1873 if (next_hop) { 1874 /* Pass IPFORWARD info if available */ 1875 1876 tag.mh_type = MT_TAG; 1877 tag.mh_flags = PACKET_TAG_IPFORWARD; 1878 tag.mh_data = (caddr_t)next_hop; 1879 tag.mh_next = m; 1880 m = (struct mbuf *)&tag; 1881 } 1882 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1883 IP_FORWARDING, 0, NULL); 1884 } 1885 if (error) 1886 ipstat.ips_cantforward++; 1887 else { 1888 ipstat.ips_forward++; 1889 if (type) 1890 ipstat.ips_redirectsent++; 1891 else { 1892 if (mcopy) { 1893 ipflow_create(&ipforward_rt, mcopy); 1894 m_freem(mcopy); 1895 } 1896 return; 1897 } 1898 } 1899 if (mcopy == NULL) 1900 return; 1901 destifp = NULL; 1902 1903 switch (error) { 1904 1905 case 0: /* forwarded, but need redirect */ 1906 /* type, code set above */ 1907 break; 1908 1909 case ENETUNREACH: /* shouldn't happen, checked above */ 1910 case EHOSTUNREACH: 1911 case ENETDOWN: 1912 case EHOSTDOWN: 1913 default: 1914 type = ICMP_UNREACH; 1915 code = ICMP_UNREACH_HOST; 1916 break; 1917 1918 case EMSGSIZE: 1919 type = ICMP_UNREACH; 1920 code = ICMP_UNREACH_NEEDFRAG; 1921 #ifdef IPSEC 1922 /* 1923 * If the packet is routed over IPsec tunnel, tell the 1924 * originator the tunnel MTU. 1925 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1926 * XXX quickhack!!! 1927 */ 1928 if (ipforward_rt.ro_rt) { 1929 struct secpolicy *sp = NULL; 1930 int ipsecerror; 1931 int ipsechdr; 1932 struct route *ro; 1933 1934 sp = ipsec4_getpolicybyaddr(mcopy, 1935 IPSEC_DIR_OUTBOUND, 1936 IP_FORWARDING, 1937 &ipsecerror); 1938 1939 if (sp == NULL) 1940 destifp = ipforward_rt.ro_rt->rt_ifp; 1941 else { 1942 /* count IPsec header size */ 1943 ipsechdr = ipsec4_hdrsiz(mcopy, 1944 IPSEC_DIR_OUTBOUND, 1945 NULL); 1946 1947 /* 1948 * find the correct route for outer IPv4 1949 * header, compute tunnel MTU. 1950 * 1951 * XXX BUG ALERT 1952 * The "dummyifp" code relies upon the fact 1953 * that icmp_error() touches only ifp->if_mtu. 1954 */ 1955 /*XXX*/ 1956 destifp = NULL; 1957 if (sp->req != NULL 1958 && sp->req->sav != NULL 1959 && sp->req->sav->sah != NULL) { 1960 ro = &sp->req->sav->sah->sa_route; 1961 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1962 dummyifp.if_mtu = 1963 ro->ro_rt->rt_ifp->if_mtu; 1964 dummyifp.if_mtu -= ipsechdr; 1965 destifp = &dummyifp; 1966 } 1967 } 1968 1969 key_freesp(sp); 1970 } 1971 } 1972 #elif FAST_IPSEC 1973 /* 1974 * If the packet is routed over IPsec tunnel, tell the 1975 * originator the tunnel MTU. 1976 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1977 * XXX quickhack!!! 1978 */ 1979 if (ipforward_rt.ro_rt) { 1980 struct secpolicy *sp = NULL; 1981 int ipsecerror; 1982 int ipsechdr; 1983 struct route *ro; 1984 1985 sp = ipsec_getpolicybyaddr(mcopy, 1986 IPSEC_DIR_OUTBOUND, 1987 IP_FORWARDING, 1988 &ipsecerror); 1989 1990 if (sp == NULL) 1991 destifp = ipforward_rt.ro_rt->rt_ifp; 1992 else { 1993 /* count IPsec header size */ 1994 ipsechdr = ipsec4_hdrsiz(mcopy, 1995 IPSEC_DIR_OUTBOUND, 1996 NULL); 1997 1998 /* 1999 * find the correct route for outer IPv4 2000 * header, compute tunnel MTU. 2001 * 2002 * XXX BUG ALERT 2003 * The "dummyifp" code relies upon the fact 2004 * that icmp_error() touches only ifp->if_mtu. 2005 */ 2006 /*XXX*/ 2007 destifp = NULL; 2008 if (sp->req != NULL 2009 && sp->req->sav != NULL 2010 && sp->req->sav->sah != NULL) { 2011 ro = &sp->req->sav->sah->sa_route; 2012 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 2013 dummyifp.if_mtu = 2014 ro->ro_rt->rt_ifp->if_mtu; 2015 dummyifp.if_mtu -= ipsechdr; 2016 destifp = &dummyifp; 2017 } 2018 } 2019 2020 KEY_FREESP(&sp); 2021 } 2022 } 2023 #else /* !IPSEC && !FAST_IPSEC */ 2024 if (ipforward_rt.ro_rt) 2025 destifp = ipforward_rt.ro_rt->rt_ifp; 2026 #endif /*IPSEC*/ 2027 ipstat.ips_cantfrag++; 2028 break; 2029 2030 case ENOBUFS: 2031 /* 2032 * A router should not generate ICMP_SOURCEQUENCH as 2033 * required in RFC1812 Requirements for IP Version 4 Routers. 2034 * Source quench could be a big problem under DoS attacks, 2035 * or if the underlying interface is rate-limited. 2036 * Those who need source quench packets may re-enable them 2037 * via the net.inet.ip.sendsourcequench sysctl. 2038 */ 2039 if (ip_sendsourcequench == 0) { 2040 m_freem(mcopy); 2041 return; 2042 } else { 2043 type = ICMP_SOURCEQUENCH; 2044 code = 0; 2045 } 2046 break; 2047 2048 case EACCES: /* ipfw denied packet */ 2049 m_freem(mcopy); 2050 return; 2051 } 2052 icmp_error(mcopy, type, code, dest, destifp); 2053 } 2054 2055 void 2056 ip_savecontrol(inp, mp, ip, m) 2057 register struct inpcb *inp; 2058 register struct mbuf **mp; 2059 register struct ip *ip; 2060 register struct mbuf *m; 2061 { 2062 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2063 struct timeval tv; 2064 2065 microtime(&tv); 2066 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2067 SCM_TIMESTAMP, SOL_SOCKET); 2068 if (*mp) 2069 mp = &(*mp)->m_next; 2070 } 2071 if (inp->inp_flags & INP_RECVDSTADDR) { 2072 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2073 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2074 if (*mp) 2075 mp = &(*mp)->m_next; 2076 } 2077 if (inp->inp_flags & INP_RECVTTL) { 2078 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2079 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2080 if (*mp) 2081 mp = &(*mp)->m_next; 2082 } 2083 #ifdef notyet 2084 /* XXX 2085 * Moving these out of udp_input() made them even more broken 2086 * than they already were. 2087 */ 2088 /* options were tossed already */ 2089 if (inp->inp_flags & INP_RECVOPTS) { 2090 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2091 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2092 if (*mp) 2093 mp = &(*mp)->m_next; 2094 } 2095 /* ip_srcroute doesn't do what we want here, need to fix */ 2096 if (inp->inp_flags & INP_RECVRETOPTS) { 2097 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2098 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2099 if (*mp) 2100 mp = &(*mp)->m_next; 2101 } 2102 #endif 2103 if (inp->inp_flags & INP_RECVIF) { 2104 struct ifnet *ifp; 2105 struct sdlbuf { 2106 struct sockaddr_dl sdl; 2107 u_char pad[32]; 2108 } sdlbuf; 2109 struct sockaddr_dl *sdp; 2110 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2111 2112 if (((ifp = m->m_pkthdr.rcvif)) 2113 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2114 sdp = (struct sockaddr_dl *) 2115 (ifaddr_byindex(ifp->if_index)->ifa_addr); 2116 /* 2117 * Change our mind and don't try copy. 2118 */ 2119 if ((sdp->sdl_family != AF_LINK) 2120 || (sdp->sdl_len > sizeof(sdlbuf))) { 2121 goto makedummy; 2122 } 2123 bcopy(sdp, sdl2, sdp->sdl_len); 2124 } else { 2125 makedummy: 2126 sdl2->sdl_len 2127 = offsetof(struct sockaddr_dl, sdl_data[0]); 2128 sdl2->sdl_family = AF_LINK; 2129 sdl2->sdl_index = 0; 2130 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2131 } 2132 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2133 IP_RECVIF, IPPROTO_IP); 2134 if (*mp) 2135 mp = &(*mp)->m_next; 2136 } 2137 } 2138 2139 /* 2140 * XXX these routines are called from the upper part of the kernel. 2141 * They need to be locked when we remove Giant. 2142 * 2143 * They could also be moved to ip_mroute.c, since all the RSVP 2144 * handling is done there already. 2145 */ 2146 static int ip_rsvp_on; 2147 struct socket *ip_rsvpd; 2148 int 2149 ip_rsvp_init(struct socket *so) 2150 { 2151 if (so->so_type != SOCK_RAW || 2152 so->so_proto->pr_protocol != IPPROTO_RSVP) 2153 return EOPNOTSUPP; 2154 2155 if (ip_rsvpd != NULL) 2156 return EADDRINUSE; 2157 2158 ip_rsvpd = so; 2159 /* 2160 * This may seem silly, but we need to be sure we don't over-increment 2161 * the RSVP counter, in case something slips up. 2162 */ 2163 if (!ip_rsvp_on) { 2164 ip_rsvp_on = 1; 2165 rsvp_on++; 2166 } 2167 2168 return 0; 2169 } 2170 2171 int 2172 ip_rsvp_done(void) 2173 { 2174 ip_rsvpd = NULL; 2175 /* 2176 * This may seem silly, but we need to be sure we don't over-decrement 2177 * the RSVP counter, in case something slips up. 2178 */ 2179 if (ip_rsvp_on) { 2180 ip_rsvp_on = 0; 2181 rsvp_on--; 2182 } 2183 return 0; 2184 } 2185 2186 void 2187 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 2188 { 2189 if (rsvp_input_p) { /* call the real one if loaded */ 2190 rsvp_input_p(m, off); 2191 return; 2192 } 2193 2194 /* Can still get packets with rsvp_on = 0 if there is a local member 2195 * of the group to which the RSVP packet is addressed. But in this 2196 * case we want to throw the packet away. 2197 */ 2198 2199 if (!rsvp_on) { 2200 m_freem(m); 2201 return; 2202 } 2203 2204 if (ip_rsvpd != NULL) { 2205 rip_input(m, off); 2206 return; 2207 } 2208 /* Drop the packet */ 2209 m_freem(m); 2210 } 2211