Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netinet/ip_input.c
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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: releng/5.2/sys/netinet/ip_input.c 122996 2003-11-26 20:31:13Z andre $ 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 #ifdef PFIL_HOOKS 158 struct pfil_head inet_pfil_hook; 159 #endif 160 161 static struct ifqueue ipintrq; 162 static int ipqmaxlen = IFQ_MAXLEN; 163 164 extern struct domain inetdomain; 165 extern struct protosw inetsw[]; 166 u_char ip_protox[IPPROTO_MAX]; 167 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 168 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */ 169 u_long in_ifaddrhmask; /* mask for hash table */ 170 171 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 172 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 173 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 174 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 175 176 struct ipstat ipstat; 177 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 178 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 179 180 /* Packet reassembly stuff */ 181 #define IPREASS_NHASH_LOG2 6 182 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 183 #define IPREASS_HMASK (IPREASS_NHASH - 1) 184 #define IPREASS_HASH(x,y) \ 185 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 186 187 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 188 struct mtx ipqlock; 189 190 #define IPQ_LOCK() mtx_lock(&ipqlock) 191 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 192 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 193 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 194 195 #ifdef IPCTL_DEFMTU 196 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 197 &ip_mtu, 0, "Default MTU"); 198 #endif 199 200 #ifdef IPSTEALTH 201 int ipstealth = 0; 202 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 203 &ipstealth, 0, ""); 204 #endif 205 206 207 /* Firewall hooks */ 208 ip_fw_chk_t *ip_fw_chk_ptr; 209 int fw_enable = 1 ; 210 int fw_one_pass = 1; 211 212 /* Dummynet hooks */ 213 ip_dn_io_t *ip_dn_io_ptr; 214 215 /* 216 * XXX this is ugly -- the following two global variables are 217 * used to store packet state while it travels through the stack. 218 * Note that the code even makes assumptions on the size and 219 * alignment of fields inside struct ip_srcrt so e.g. adding some 220 * fields will break the code. This needs to be fixed. 221 * 222 * We need to save the IP options in case a protocol wants to respond 223 * to an incoming packet over the same route if the packet got here 224 * using IP source routing. This allows connection establishment and 225 * maintenance when the remote end is on a network that is not known 226 * to us. 227 */ 228 static int ip_nhops = 0; 229 static struct ip_srcrt { 230 struct in_addr dst; /* final destination */ 231 char nop; /* one NOP to align */ 232 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 233 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 234 } ip_srcrt; 235 236 static void save_rte(u_char *, struct in_addr); 237 static int ip_dooptions(struct mbuf *m, int, 238 struct sockaddr_in *next_hop); 239 static void ip_forward(struct mbuf *m, int srcrt, 240 struct sockaddr_in *next_hop); 241 static void ip_freef(struct ipqhead *, struct ipq *); 242 static struct mbuf *ip_reass(struct mbuf *, struct ipqhead *, 243 struct ipq *, u_int32_t *, u_int16_t *); 244 245 /* 246 * IP initialization: fill in IP protocol switch table. 247 * All protocols not implemented in kernel go to raw IP protocol handler. 248 */ 249 void 250 ip_init() 251 { 252 register struct protosw *pr; 253 register int i; 254 255 TAILQ_INIT(&in_ifaddrhead); 256 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 257 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 258 if (pr == 0) 259 panic("ip_init"); 260 for (i = 0; i < IPPROTO_MAX; i++) 261 ip_protox[i] = pr - inetsw; 262 for (pr = inetdomain.dom_protosw; 263 pr < inetdomain.dom_protoswNPROTOSW; pr++) 264 if (pr->pr_domain->dom_family == PF_INET && 265 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 266 ip_protox[pr->pr_protocol] = pr - inetsw; 267 268 #ifdef PFIL_HOOKS 269 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 270 inet_pfil_hook.ph_af = AF_INET; 271 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 272 printf("%s: WARNING: unable to register pfil hook, " 273 "error %d\n", __func__, i); 274 #endif /* PFIL_HOOKS */ 275 276 IPQ_LOCK_INIT(); 277 for (i = 0; i < IPREASS_NHASH; i++) 278 TAILQ_INIT(&ipq[i]); 279 280 maxnipq = nmbclusters / 32; 281 maxfragsperpacket = 16; 282 283 #ifndef RANDOM_IP_ID 284 ip_id = time_second & 0xffff; 285 #endif 286 ipintrq.ifq_maxlen = ipqmaxlen; 287 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 288 netisr_register(NETISR_IP, ip_input, &ipintrq, NETISR_MPSAFE); 289 } 290 291 /* 292 * Ip input routine. Checksum and byte swap header. If fragmented 293 * try to reassemble. Process options. Pass to next level. 294 */ 295 void 296 ip_input(struct mbuf *m) 297 { 298 struct ip *ip = NULL; 299 struct ipq *fp; 300 struct in_ifaddr *ia = NULL; 301 struct ifaddr *ifa; 302 int i, checkif, hlen = 0; 303 int ours = 0; 304 u_short sum; 305 struct in_addr pkt_dst; 306 u_int32_t divert_info = 0; /* packet divert/tee info */ 307 struct ip_fw_args args; 308 int dchg = 0; /* dest changed after fw */ 309 #ifdef PFIL_HOOKS 310 struct in_addr odst; /* original dst address */ 311 #endif 312 #ifdef FAST_IPSEC 313 struct m_tag *mtag; 314 struct tdb_ident *tdbi; 315 struct secpolicy *sp; 316 int s, error; 317 #endif /* FAST_IPSEC */ 318 319 args.eh = NULL; 320 args.oif = NULL; 321 args.rule = NULL; 322 args.divert_rule = 0; /* divert cookie */ 323 args.next_hop = NULL; 324 325 /* 326 * Grab info from MT_TAG mbufs prepended to the chain. 327 * 328 * XXX: This is ugly. These pseudo mbuf prepend tags should really 329 * be real m_tags. Before these have always been allocated on the 330 * callers stack, so we didn't have to free them. Now with 331 * ip_fastforward they are true mbufs and we have to free them 332 * otherwise we have a leak. Must rewrite ipfw to use m_tags. 333 */ 334 for (; m && m->m_type == MT_TAG;) { 335 struct mbuf *m0; 336 337 switch(m->_m_tag_id) { 338 default: 339 printf("ip_input: unrecognised MT_TAG tag %d\n", 340 m->_m_tag_id); 341 break; 342 343 case PACKET_TAG_DUMMYNET: 344 args.rule = ((struct dn_pkt *)m)->rule; 345 break; 346 347 case PACKET_TAG_DIVERT: 348 args.divert_rule = (intptr_t)m->m_hdr.mh_data & 0xffff; 349 break; 350 351 case PACKET_TAG_IPFORWARD: 352 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 353 break; 354 355 case PACKET_TAG_IPFASTFWD_OURS: 356 ours = 1; 357 break; 358 } 359 360 m0 = m; 361 m = m->m_next; 362 /* XXX: This is set by ip_fastforward */ 363 if (m0->m_nextpkt == (struct mbuf *)1) 364 m_free(m0); 365 } 366 367 M_ASSERTPKTHDR(m); 368 369 if (ours) /* ip_fastforward firewall changed dest to local */ 370 goto ours; 371 372 if (args.rule) { /* dummynet already filtered us */ 373 ip = mtod(m, struct ip *); 374 hlen = ip->ip_hl << 2; 375 goto iphack ; 376 } 377 378 ipstat.ips_total++; 379 380 if (m->m_pkthdr.len < sizeof(struct ip)) 381 goto tooshort; 382 383 if (m->m_len < sizeof (struct ip) && 384 (m = m_pullup(m, sizeof (struct ip))) == 0) { 385 ipstat.ips_toosmall++; 386 return; 387 } 388 ip = mtod(m, struct ip *); 389 390 if (ip->ip_v != IPVERSION) { 391 ipstat.ips_badvers++; 392 goto bad; 393 } 394 395 hlen = ip->ip_hl << 2; 396 if (hlen < sizeof(struct ip)) { /* minimum header length */ 397 ipstat.ips_badhlen++; 398 goto bad; 399 } 400 if (hlen > m->m_len) { 401 if ((m = m_pullup(m, hlen)) == 0) { 402 ipstat.ips_badhlen++; 403 return; 404 } 405 ip = mtod(m, struct ip *); 406 } 407 408 /* 127/8 must not appear on wire - RFC1122 */ 409 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 410 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 411 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 412 ipstat.ips_badaddr++; 413 goto bad; 414 } 415 } 416 417 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 418 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 419 } else { 420 if (hlen == sizeof(struct ip)) { 421 sum = in_cksum_hdr(ip); 422 } else { 423 sum = in_cksum(m, hlen); 424 } 425 } 426 if (sum) { 427 ipstat.ips_badsum++; 428 goto bad; 429 } 430 431 /* 432 * Convert fields to host representation. 433 */ 434 ip->ip_len = ntohs(ip->ip_len); 435 if (ip->ip_len < hlen) { 436 ipstat.ips_badlen++; 437 goto bad; 438 } 439 ip->ip_off = ntohs(ip->ip_off); 440 441 /* 442 * Check that the amount of data in the buffers 443 * is as at least much as the IP header would have us expect. 444 * Trim mbufs if longer than we expect. 445 * Drop packet if shorter than we expect. 446 */ 447 if (m->m_pkthdr.len < ip->ip_len) { 448 tooshort: 449 ipstat.ips_tooshort++; 450 goto bad; 451 } 452 if (m->m_pkthdr.len > ip->ip_len) { 453 if (m->m_len == m->m_pkthdr.len) { 454 m->m_len = ip->ip_len; 455 m->m_pkthdr.len = ip->ip_len; 456 } else 457 m_adj(m, ip->ip_len - m->m_pkthdr.len); 458 } 459 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 460 /* 461 * Bypass packet filtering for packets from a tunnel (gif). 462 */ 463 if (ipsec_getnhist(m)) 464 goto pass; 465 #endif 466 #if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF) 467 /* 468 * Bypass packet filtering for packets from a tunnel (gif). 469 */ 470 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 471 goto pass; 472 #endif 473 474 /* 475 * IpHack's section. 476 * Right now when no processing on packet has done 477 * and it is still fresh out of network we do our black 478 * deals with it. 479 * - Firewall: deny/allow/divert 480 * - Xlate: translate packet's addr/port (NAT). 481 * - Pipe: pass pkt through dummynet. 482 * - Wrap: fake packet's addr/port <unimpl.> 483 * - Encapsulate: put it in another IP and send out. <unimp.> 484 */ 485 486 iphack: 487 488 #ifdef PFIL_HOOKS 489 /* 490 * Run through list of hooks for input packets. 491 * 492 * NB: Beware of the destination address changing (e.g. 493 * by NAT rewriting). When this happens, tell 494 * ip_forward to do the right thing. 495 */ 496 odst = ip->ip_dst; 497 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 498 PFIL_IN) != 0) 499 return; 500 if (m == NULL) /* consumed by filter */ 501 return; 502 ip = mtod(m, struct ip *); 503 dchg = (odst.s_addr != ip->ip_dst.s_addr); 504 #endif /* PFIL_HOOKS */ 505 506 if (fw_enable && IPFW_LOADED) { 507 /* 508 * If we've been forwarded from the output side, then 509 * skip the firewall a second time 510 */ 511 if (args.next_hop) 512 goto ours; 513 514 args.m = m; 515 i = ip_fw_chk_ptr(&args); 516 m = args.m; 517 518 if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 519 if (m) 520 m_freem(m); 521 return; 522 } 523 ip = mtod(m, struct ip *); /* just in case m changed */ 524 if (i == 0 && args.next_hop == NULL) /* common case */ 525 goto pass; 526 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) { 527 /* Send packet to the appropriate pipe */ 528 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 529 return; 530 } 531 #ifdef IPDIVERT 532 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 533 /* Divert or tee packet */ 534 divert_info = i; 535 goto ours; 536 } 537 #endif 538 if (i == 0 && args.next_hop != NULL) 539 goto pass; 540 /* 541 * if we get here, the packet must be dropped 542 */ 543 m_freem(m); 544 return; 545 } 546 pass: 547 548 /* 549 * Process options and, if not destined for us, 550 * ship it on. ip_dooptions returns 1 when an 551 * error was detected (causing an icmp message 552 * to be sent and the original packet to be freed). 553 */ 554 ip_nhops = 0; /* for source routed packets */ 555 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, args.next_hop)) 556 return; 557 558 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 559 * matter if it is destined to another node, or whether it is 560 * a multicast one, RSVP wants it! and prevents it from being forwarded 561 * anywhere else. Also checks if the rsvp daemon is running before 562 * grabbing the packet. 563 */ 564 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 565 goto ours; 566 567 /* 568 * Check our list of addresses, to see if the packet is for us. 569 * If we don't have any addresses, assume any unicast packet 570 * we receive might be for us (and let the upper layers deal 571 * with it). 572 */ 573 if (TAILQ_EMPTY(&in_ifaddrhead) && 574 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 575 goto ours; 576 577 /* 578 * Cache the destination address of the packet; this may be 579 * changed by use of 'ipfw fwd'. 580 */ 581 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 582 583 /* 584 * Enable a consistency check between the destination address 585 * and the arrival interface for a unicast packet (the RFC 1122 586 * strong ES model) if IP forwarding is disabled and the packet 587 * is not locally generated and the packet is not subject to 588 * 'ipfw fwd'. 589 * 590 * XXX - Checking also should be disabled if the destination 591 * address is ipnat'ed to a different interface. 592 * 593 * XXX - Checking is incompatible with IP aliases added 594 * to the loopback interface instead of the interface where 595 * the packets are received. 596 */ 597 checkif = ip_checkinterface && (ipforwarding == 0) && 598 m->m_pkthdr.rcvif != NULL && 599 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 600 (args.next_hop == NULL); 601 602 /* 603 * Check for exact addresses in the hash bucket. 604 */ 605 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 606 /* 607 * If the address matches, verify that the packet 608 * arrived via the correct interface if checking is 609 * enabled. 610 */ 611 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 612 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 613 goto ours; 614 } 615 /* 616 * Check for broadcast addresses. 617 * 618 * Only accept broadcast packets that arrive via the matching 619 * interface. Reception of forwarded directed broadcasts would 620 * be handled via ip_forward() and ether_output() with the loopback 621 * into the stack for SIMPLEX interfaces handled by ether_output(). 622 */ 623 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 624 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 625 if (ifa->ifa_addr->sa_family != AF_INET) 626 continue; 627 ia = ifatoia(ifa); 628 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 629 pkt_dst.s_addr) 630 goto ours; 631 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 632 goto ours; 633 #ifdef BOOTP_COMPAT 634 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 635 goto ours; 636 #endif 637 } 638 } 639 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 640 struct in_multi *inm; 641 if (ip_mrouter) { 642 /* 643 * If we are acting as a multicast router, all 644 * incoming multicast packets are passed to the 645 * kernel-level multicast forwarding function. 646 * The packet is returned (relatively) intact; if 647 * ip_mforward() returns a non-zero value, the packet 648 * must be discarded, else it may be accepted below. 649 */ 650 if (ip_mforward && 651 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 652 ipstat.ips_cantforward++; 653 m_freem(m); 654 return; 655 } 656 657 /* 658 * The process-level routing daemon needs to receive 659 * all multicast IGMP packets, whether or not this 660 * host belongs to their destination groups. 661 */ 662 if (ip->ip_p == IPPROTO_IGMP) 663 goto ours; 664 ipstat.ips_forward++; 665 } 666 /* 667 * See if we belong to the destination multicast group on the 668 * arrival interface. 669 */ 670 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 671 if (inm == NULL) { 672 ipstat.ips_notmember++; 673 m_freem(m); 674 return; 675 } 676 goto ours; 677 } 678 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 679 goto ours; 680 if (ip->ip_dst.s_addr == INADDR_ANY) 681 goto ours; 682 683 /* 684 * FAITH(Firewall Aided Internet Translator) 685 */ 686 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 687 if (ip_keepfaith) { 688 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 689 goto ours; 690 } 691 m_freem(m); 692 return; 693 } 694 695 /* 696 * Not for us; forward if possible and desirable. 697 */ 698 if (ipforwarding == 0) { 699 ipstat.ips_cantforward++; 700 m_freem(m); 701 } else { 702 #ifdef IPSEC 703 /* 704 * Enforce inbound IPsec SPD. 705 */ 706 if (ipsec4_in_reject(m, NULL)) { 707 ipsecstat.in_polvio++; 708 goto bad; 709 } 710 #endif /* IPSEC */ 711 #ifdef FAST_IPSEC 712 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 713 s = splnet(); 714 if (mtag != NULL) { 715 tdbi = (struct tdb_ident *)(mtag + 1); 716 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 717 } else { 718 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 719 IP_FORWARDING, &error); 720 } 721 if (sp == NULL) { /* NB: can happen if error */ 722 splx(s); 723 /*XXX error stat???*/ 724 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 725 goto bad; 726 } 727 728 /* 729 * Check security policy against packet attributes. 730 */ 731 error = ipsec_in_reject(sp, m); 732 KEY_FREESP(&sp); 733 splx(s); 734 if (error) { 735 ipstat.ips_cantforward++; 736 goto bad; 737 } 738 #endif /* FAST_IPSEC */ 739 ip_forward(m, dchg, args.next_hop); 740 } 741 return; 742 743 ours: 744 #ifdef IPSTEALTH 745 /* 746 * IPSTEALTH: Process non-routing options only 747 * if the packet is destined for us. 748 */ 749 if (ipstealth && hlen > sizeof (struct ip) && 750 ip_dooptions(m, 1, args.next_hop)) 751 return; 752 #endif /* IPSTEALTH */ 753 754 /* Count the packet in the ip address stats */ 755 if (ia != NULL) { 756 ia->ia_ifa.if_ipackets++; 757 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 758 } 759 760 /* 761 * If offset or IP_MF are set, must reassemble. 762 * Otherwise, nothing need be done. 763 * (We could look in the reassembly queue to see 764 * if the packet was previously fragmented, 765 * but it's not worth the time; just let them time out.) 766 */ 767 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 768 769 /* If maxnipq is 0, never accept fragments. */ 770 if (maxnipq == 0) { 771 ipstat.ips_fragments++; 772 ipstat.ips_fragdropped++; 773 goto bad; 774 } 775 776 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 777 IPQ_LOCK(); 778 /* 779 * Look for queue of fragments 780 * of this datagram. 781 */ 782 TAILQ_FOREACH(fp, &ipq[sum], ipq_list) 783 if (ip->ip_id == fp->ipq_id && 784 ip->ip_src.s_addr == fp->ipq_src.s_addr && 785 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 786 #ifdef MAC 787 mac_fragment_match(m, fp) && 788 #endif 789 ip->ip_p == fp->ipq_p) 790 goto found; 791 792 fp = NULL; 793 794 /* 795 * Enforce upper bound on number of fragmented packets 796 * for which we attempt reassembly; 797 * If maxnipq is -1, accept all fragments without limitation. 798 */ 799 if ((nipq > maxnipq) && (maxnipq > 0)) { 800 /* 801 * drop something from the tail of the current queue 802 * before proceeding further 803 */ 804 struct ipq *q = TAILQ_LAST(&ipq[sum], ipqhead); 805 if (q == NULL) { /* gak */ 806 for (i = 0; i < IPREASS_NHASH; i++) { 807 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 808 if (r) { 809 ipstat.ips_fragtimeout += r->ipq_nfrags; 810 ip_freef(&ipq[i], r); 811 break; 812 } 813 } 814 } else { 815 ipstat.ips_fragtimeout += q->ipq_nfrags; 816 ip_freef(&ipq[sum], q); 817 } 818 } 819 found: 820 /* 821 * Adjust ip_len to not reflect header, 822 * convert offset of this to bytes. 823 */ 824 ip->ip_len -= hlen; 825 if (ip->ip_off & IP_MF) { 826 /* 827 * Make sure that fragments have a data length 828 * that's a non-zero multiple of 8 bytes. 829 */ 830 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 831 IPQ_UNLOCK(); 832 ipstat.ips_toosmall++; /* XXX */ 833 goto bad; 834 } 835 m->m_flags |= M_FRAG; 836 } else 837 m->m_flags &= ~M_FRAG; 838 ip->ip_off <<= 3; 839 840 /* 841 * Attempt reassembly; if it succeeds, proceed. 842 * ip_reass() will return a different mbuf, and update 843 * the divert info in divert_info and args.divert_rule. 844 */ 845 ipstat.ips_fragments++; 846 m->m_pkthdr.header = ip; 847 m = ip_reass(m, 848 &ipq[sum], fp, &divert_info, &args.divert_rule); 849 IPQ_UNLOCK(); 850 if (m == 0) 851 return; 852 ipstat.ips_reassembled++; 853 ip = mtod(m, struct ip *); 854 /* Get the header length of the reassembled packet */ 855 hlen = ip->ip_hl << 2; 856 #ifdef IPDIVERT 857 /* Restore original checksum before diverting packet */ 858 if (divert_info != 0) { 859 ip->ip_len += hlen; 860 ip->ip_len = htons(ip->ip_len); 861 ip->ip_off = htons(ip->ip_off); 862 ip->ip_sum = 0; 863 if (hlen == sizeof(struct ip)) 864 ip->ip_sum = in_cksum_hdr(ip); 865 else 866 ip->ip_sum = in_cksum(m, hlen); 867 ip->ip_off = ntohs(ip->ip_off); 868 ip->ip_len = ntohs(ip->ip_len); 869 ip->ip_len -= hlen; 870 } 871 #endif 872 } else 873 ip->ip_len -= hlen; 874 875 #ifdef IPDIVERT 876 /* 877 * Divert or tee packet to the divert protocol if required. 878 */ 879 if (divert_info != 0) { 880 struct mbuf *clone = NULL; 881 882 /* Clone packet if we're doing a 'tee' */ 883 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 884 clone = m_dup(m, M_DONTWAIT); 885 886 /* Restore packet header fields to original values */ 887 ip->ip_len += hlen; 888 ip->ip_len = htons(ip->ip_len); 889 ip->ip_off = htons(ip->ip_off); 890 891 /* Deliver packet to divert input routine */ 892 divert_packet(m, 1, divert_info & 0xffff, args.divert_rule); 893 ipstat.ips_delivered++; 894 895 /* If 'tee', continue with original packet */ 896 if (clone == NULL) 897 return; 898 m = clone; 899 ip = mtod(m, struct ip *); 900 ip->ip_len += hlen; 901 /* 902 * Jump backwards to complete processing of the 903 * packet. But first clear divert_info to avoid 904 * entering this block again. 905 * We do not need to clear args.divert_rule 906 * or args.next_hop as they will not be used. 907 */ 908 divert_info = 0; 909 goto pass; 910 } 911 #endif 912 913 #ifdef IPSEC 914 /* 915 * enforce IPsec policy checking if we are seeing last header. 916 * note that we do not visit this with protocols with pcb layer 917 * code - like udp/tcp/raw ip. 918 */ 919 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 920 ipsec4_in_reject(m, NULL)) { 921 ipsecstat.in_polvio++; 922 goto bad; 923 } 924 #endif 925 #if FAST_IPSEC 926 /* 927 * enforce IPsec policy checking if we are seeing last header. 928 * note that we do not visit this with protocols with pcb layer 929 * code - like udp/tcp/raw ip. 930 */ 931 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 932 /* 933 * Check if the packet has already had IPsec processing 934 * done. If so, then just pass it along. This tag gets 935 * set during AH, ESP, etc. input handling, before the 936 * packet is returned to the ip input queue for delivery. 937 */ 938 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 939 s = splnet(); 940 if (mtag != NULL) { 941 tdbi = (struct tdb_ident *)(mtag + 1); 942 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 943 } else { 944 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 945 IP_FORWARDING, &error); 946 } 947 if (sp != NULL) { 948 /* 949 * Check security policy against packet attributes. 950 */ 951 error = ipsec_in_reject(sp, m); 952 KEY_FREESP(&sp); 953 } else { 954 /* XXX error stat??? */ 955 error = EINVAL; 956 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 957 goto bad; 958 } 959 splx(s); 960 if (error) 961 goto bad; 962 } 963 #endif /* FAST_IPSEC */ 964 965 /* 966 * Switch out to protocol's input routine. 967 */ 968 ipstat.ips_delivered++; 969 NET_PICKUP_GIANT(); 970 if (args.next_hop && ip->ip_p == IPPROTO_TCP) { 971 /* TCP needs IPFORWARD info if available */ 972 struct m_hdr tag; 973 974 tag.mh_type = MT_TAG; 975 tag.mh_flags = PACKET_TAG_IPFORWARD; 976 tag.mh_data = (caddr_t)args.next_hop; 977 tag.mh_next = m; 978 tag.mh_nextpkt = NULL; 979 980 (*inetsw[ip_protox[ip->ip_p]].pr_input)( 981 (struct mbuf *)&tag, hlen); 982 } else 983 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 984 NET_DROP_GIANT(); 985 return; 986 bad: 987 m_freem(m); 988 } 989 990 /* 991 * Take incoming datagram fragment and try to reassemble it into 992 * whole datagram. If a chain for reassembly of this datagram already 993 * exists, then it is given as fp; otherwise have to make a chain. 994 * 995 * When IPDIVERT enabled, keep additional state with each packet that 996 * tells us if we need to divert or tee the packet we're building. 997 * In particular, *divinfo includes the port and TEE flag, 998 * *divert_rule is the number of the matching rule. 999 */ 1000 1001 static struct mbuf * 1002 ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp, 1003 u_int32_t *divinfo, u_int16_t *divert_rule) 1004 { 1005 struct ip *ip = mtod(m, struct ip *); 1006 register struct mbuf *p, *q, *nq; 1007 struct mbuf *t; 1008 int hlen = ip->ip_hl << 2; 1009 int i, next; 1010 u_int8_t ecn, ecn0; 1011 1012 IPQ_LOCK_ASSERT(); 1013 1014 /* 1015 * Presence of header sizes in mbufs 1016 * would confuse code below. 1017 */ 1018 m->m_data += hlen; 1019 m->m_len -= hlen; 1020 1021 /* 1022 * If first fragment to arrive, create a reassembly queue. 1023 */ 1024 if (fp == NULL) { 1025 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 1026 goto dropfrag; 1027 fp = mtod(t, struct ipq *); 1028 #ifdef MAC 1029 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 1030 m_free(t); 1031 goto dropfrag; 1032 } 1033 mac_create_ipq(m, fp); 1034 #endif 1035 TAILQ_INSERT_HEAD(head, fp, ipq_list); 1036 nipq++; 1037 fp->ipq_nfrags = 1; 1038 fp->ipq_ttl = IPFRAGTTL; 1039 fp->ipq_p = ip->ip_p; 1040 fp->ipq_id = ip->ip_id; 1041 fp->ipq_src = ip->ip_src; 1042 fp->ipq_dst = ip->ip_dst; 1043 fp->ipq_frags = m; 1044 m->m_nextpkt = NULL; 1045 #ifdef IPDIVERT 1046 fp->ipq_div_info = 0; 1047 fp->ipq_div_cookie = 0; 1048 #endif 1049 goto inserted; 1050 } else { 1051 fp->ipq_nfrags++; 1052 #ifdef MAC 1053 mac_update_ipq(m, fp); 1054 #endif 1055 } 1056 1057 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1058 1059 /* 1060 * Handle ECN by comparing this segment with the first one; 1061 * if CE is set, do not lose CE. 1062 * drop if CE and not-ECT are mixed for the same packet. 1063 */ 1064 ecn = ip->ip_tos & IPTOS_ECN_MASK; 1065 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 1066 if (ecn == IPTOS_ECN_CE) { 1067 if (ecn0 == IPTOS_ECN_NOTECT) 1068 goto dropfrag; 1069 if (ecn0 != IPTOS_ECN_CE) 1070 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 1071 } 1072 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 1073 goto dropfrag; 1074 1075 /* 1076 * Find a segment which begins after this one does. 1077 */ 1078 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1079 if (GETIP(q)->ip_off > ip->ip_off) 1080 break; 1081 1082 /* 1083 * If there is a preceding segment, it may provide some of 1084 * our data already. If so, drop the data from the incoming 1085 * segment. If it provides all of our data, drop us, otherwise 1086 * stick new segment in the proper place. 1087 * 1088 * If some of the data is dropped from the the preceding 1089 * segment, then it's checksum is invalidated. 1090 */ 1091 if (p) { 1092 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1093 if (i > 0) { 1094 if (i >= ip->ip_len) 1095 goto dropfrag; 1096 m_adj(m, i); 1097 m->m_pkthdr.csum_flags = 0; 1098 ip->ip_off += i; 1099 ip->ip_len -= i; 1100 } 1101 m->m_nextpkt = p->m_nextpkt; 1102 p->m_nextpkt = m; 1103 } else { 1104 m->m_nextpkt = fp->ipq_frags; 1105 fp->ipq_frags = m; 1106 } 1107 1108 /* 1109 * While we overlap succeeding segments trim them or, 1110 * if they are completely covered, dequeue them. 1111 */ 1112 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1113 q = nq) { 1114 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1115 if (i < GETIP(q)->ip_len) { 1116 GETIP(q)->ip_len -= i; 1117 GETIP(q)->ip_off += i; 1118 m_adj(q, i); 1119 q->m_pkthdr.csum_flags = 0; 1120 break; 1121 } 1122 nq = q->m_nextpkt; 1123 m->m_nextpkt = nq; 1124 ipstat.ips_fragdropped++; 1125 fp->ipq_nfrags--; 1126 m_freem(q); 1127 } 1128 1129 inserted: 1130 1131 #ifdef IPDIVERT 1132 /* 1133 * Transfer firewall instructions to the fragment structure. 1134 * Only trust info in the fragment at offset 0. 1135 */ 1136 if (ip->ip_off == 0) { 1137 fp->ipq_div_info = *divinfo; 1138 fp->ipq_div_cookie = *divert_rule; 1139 } 1140 *divinfo = 0; 1141 *divert_rule = 0; 1142 #endif 1143 1144 /* 1145 * Check for complete reassembly and perform frag per packet 1146 * limiting. 1147 * 1148 * Frag limiting is performed here so that the nth frag has 1149 * a chance to complete the packet before we drop the packet. 1150 * As a result, n+1 frags are actually allowed per packet, but 1151 * only n will ever be stored. (n = maxfragsperpacket.) 1152 * 1153 */ 1154 next = 0; 1155 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1156 if (GETIP(q)->ip_off != next) { 1157 if (fp->ipq_nfrags > maxfragsperpacket) { 1158 ipstat.ips_fragdropped += fp->ipq_nfrags; 1159 ip_freef(head, fp); 1160 } 1161 return (0); 1162 } 1163 next += GETIP(q)->ip_len; 1164 } 1165 /* Make sure the last packet didn't have the IP_MF flag */ 1166 if (p->m_flags & M_FRAG) { 1167 if (fp->ipq_nfrags > maxfragsperpacket) { 1168 ipstat.ips_fragdropped += fp->ipq_nfrags; 1169 ip_freef(head, fp); 1170 } 1171 return (0); 1172 } 1173 1174 /* 1175 * Reassembly is complete. Make sure the packet is a sane size. 1176 */ 1177 q = fp->ipq_frags; 1178 ip = GETIP(q); 1179 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1180 ipstat.ips_toolong++; 1181 ipstat.ips_fragdropped += fp->ipq_nfrags; 1182 ip_freef(head, fp); 1183 return (0); 1184 } 1185 1186 /* 1187 * Concatenate fragments. 1188 */ 1189 m = q; 1190 t = m->m_next; 1191 m->m_next = 0; 1192 m_cat(m, t); 1193 nq = q->m_nextpkt; 1194 q->m_nextpkt = 0; 1195 for (q = nq; q != NULL; q = nq) { 1196 nq = q->m_nextpkt; 1197 q->m_nextpkt = NULL; 1198 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1199 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1200 m_cat(m, q); 1201 } 1202 #ifdef MAC 1203 mac_create_datagram_from_ipq(fp, m); 1204 mac_destroy_ipq(fp); 1205 #endif 1206 1207 #ifdef IPDIVERT 1208 /* 1209 * Extract firewall instructions from the fragment structure. 1210 */ 1211 *divinfo = fp->ipq_div_info; 1212 *divert_rule = fp->ipq_div_cookie; 1213 #endif 1214 1215 /* 1216 * Create header for new ip packet by 1217 * modifying header of first packet; 1218 * dequeue and discard fragment reassembly header. 1219 * Make header visible. 1220 */ 1221 ip->ip_len = next; 1222 ip->ip_src = fp->ipq_src; 1223 ip->ip_dst = fp->ipq_dst; 1224 TAILQ_REMOVE(head, fp, ipq_list); 1225 nipq--; 1226 (void) m_free(dtom(fp)); 1227 m->m_len += (ip->ip_hl << 2); 1228 m->m_data -= (ip->ip_hl << 2); 1229 /* some debugging cruft by sklower, below, will go away soon */ 1230 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1231 m_fixhdr(m); 1232 return (m); 1233 1234 dropfrag: 1235 #ifdef IPDIVERT 1236 *divinfo = 0; 1237 *divert_rule = 0; 1238 #endif 1239 ipstat.ips_fragdropped++; 1240 if (fp != NULL) 1241 fp->ipq_nfrags--; 1242 m_freem(m); 1243 return (0); 1244 1245 #undef GETIP 1246 } 1247 1248 /* 1249 * Free a fragment reassembly header and all 1250 * associated datagrams. 1251 */ 1252 static void 1253 ip_freef(fhp, fp) 1254 struct ipqhead *fhp; 1255 struct ipq *fp; 1256 { 1257 register struct mbuf *q; 1258 1259 IPQ_LOCK_ASSERT(); 1260 1261 while (fp->ipq_frags) { 1262 q = fp->ipq_frags; 1263 fp->ipq_frags = q->m_nextpkt; 1264 m_freem(q); 1265 } 1266 TAILQ_REMOVE(fhp, fp, ipq_list); 1267 (void) m_free(dtom(fp)); 1268 nipq--; 1269 } 1270 1271 /* 1272 * IP timer processing; 1273 * if a timer expires on a reassembly 1274 * queue, discard it. 1275 */ 1276 void 1277 ip_slowtimo() 1278 { 1279 register struct ipq *fp; 1280 int s = splnet(); 1281 int i; 1282 1283 IPQ_LOCK(); 1284 for (i = 0; i < IPREASS_NHASH; i++) { 1285 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1286 struct ipq *fpp; 1287 1288 fpp = fp; 1289 fp = TAILQ_NEXT(fp, ipq_list); 1290 if(--fpp->ipq_ttl == 0) { 1291 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1292 ip_freef(&ipq[i], fpp); 1293 } 1294 } 1295 } 1296 /* 1297 * If we are over the maximum number of fragments 1298 * (due to the limit being lowered), drain off 1299 * enough to get down to the new limit. 1300 */ 1301 if (maxnipq >= 0 && nipq > maxnipq) { 1302 for (i = 0; i < IPREASS_NHASH; i++) { 1303 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1304 ipstat.ips_fragdropped += 1305 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1306 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1307 } 1308 } 1309 } 1310 IPQ_UNLOCK(); 1311 splx(s); 1312 } 1313 1314 /* 1315 * Drain off all datagram fragments. 1316 */ 1317 void 1318 ip_drain() 1319 { 1320 int i; 1321 1322 IPQ_LOCK(); 1323 for (i = 0; i < IPREASS_NHASH; i++) { 1324 while(!TAILQ_EMPTY(&ipq[i])) { 1325 ipstat.ips_fragdropped += 1326 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1327 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1328 } 1329 } 1330 IPQ_UNLOCK(); 1331 in_rtqdrain(); 1332 } 1333 1334 /* 1335 * Do option processing on a datagram, 1336 * possibly discarding it if bad options are encountered, 1337 * or forwarding it if source-routed. 1338 * The pass argument is used when operating in the IPSTEALTH 1339 * mode to tell what options to process: 1340 * [LS]SRR (pass 0) or the others (pass 1). 1341 * The reason for as many as two passes is that when doing IPSTEALTH, 1342 * non-routing options should be processed only if the packet is for us. 1343 * Returns 1 if packet has been forwarded/freed, 1344 * 0 if the packet should be processed further. 1345 */ 1346 static int 1347 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1348 { 1349 struct ip *ip = mtod(m, struct ip *); 1350 u_char *cp; 1351 struct in_ifaddr *ia; 1352 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1353 struct in_addr *sin, dst; 1354 n_time ntime; 1355 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 1356 1357 dst = ip->ip_dst; 1358 cp = (u_char *)(ip + 1); 1359 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1360 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1361 opt = cp[IPOPT_OPTVAL]; 1362 if (opt == IPOPT_EOL) 1363 break; 1364 if (opt == IPOPT_NOP) 1365 optlen = 1; 1366 else { 1367 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1368 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1369 goto bad; 1370 } 1371 optlen = cp[IPOPT_OLEN]; 1372 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1373 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1374 goto bad; 1375 } 1376 } 1377 switch (opt) { 1378 1379 default: 1380 break; 1381 1382 /* 1383 * Source routing with record. 1384 * Find interface with current destination address. 1385 * If none on this machine then drop if strictly routed, 1386 * or do nothing if loosely routed. 1387 * Record interface address and bring up next address 1388 * component. If strictly routed make sure next 1389 * address is on directly accessible net. 1390 */ 1391 case IPOPT_LSRR: 1392 case IPOPT_SSRR: 1393 #ifdef IPSTEALTH 1394 if (ipstealth && pass > 0) 1395 break; 1396 #endif 1397 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1398 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1399 goto bad; 1400 } 1401 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1402 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1403 goto bad; 1404 } 1405 ipaddr.sin_addr = ip->ip_dst; 1406 ia = (struct in_ifaddr *) 1407 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1408 if (ia == 0) { 1409 if (opt == IPOPT_SSRR) { 1410 type = ICMP_UNREACH; 1411 code = ICMP_UNREACH_SRCFAIL; 1412 goto bad; 1413 } 1414 if (!ip_dosourceroute) 1415 goto nosourcerouting; 1416 /* 1417 * Loose routing, and not at next destination 1418 * yet; nothing to do except forward. 1419 */ 1420 break; 1421 } 1422 off--; /* 0 origin */ 1423 if (off > optlen - (int)sizeof(struct in_addr)) { 1424 /* 1425 * End of source route. Should be for us. 1426 */ 1427 if (!ip_acceptsourceroute) 1428 goto nosourcerouting; 1429 save_rte(cp, ip->ip_src); 1430 break; 1431 } 1432 #ifdef IPSTEALTH 1433 if (ipstealth) 1434 goto dropit; 1435 #endif 1436 if (!ip_dosourceroute) { 1437 if (ipforwarding) { 1438 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1439 /* 1440 * Acting as a router, so generate ICMP 1441 */ 1442 nosourcerouting: 1443 strcpy(buf, inet_ntoa(ip->ip_dst)); 1444 log(LOG_WARNING, 1445 "attempted source route from %s to %s\n", 1446 inet_ntoa(ip->ip_src), buf); 1447 type = ICMP_UNREACH; 1448 code = ICMP_UNREACH_SRCFAIL; 1449 goto bad; 1450 } else { 1451 /* 1452 * Not acting as a router, so silently drop. 1453 */ 1454 #ifdef IPSTEALTH 1455 dropit: 1456 #endif 1457 ipstat.ips_cantforward++; 1458 m_freem(m); 1459 return (1); 1460 } 1461 } 1462 1463 /* 1464 * locate outgoing interface 1465 */ 1466 (void)memcpy(&ipaddr.sin_addr, cp + off, 1467 sizeof(ipaddr.sin_addr)); 1468 1469 if (opt == IPOPT_SSRR) { 1470 #define INA struct in_ifaddr * 1471 #define SA struct sockaddr * 1472 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1473 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1474 } else 1475 ia = ip_rtaddr(ipaddr.sin_addr); 1476 if (ia == 0) { 1477 type = ICMP_UNREACH; 1478 code = ICMP_UNREACH_SRCFAIL; 1479 goto bad; 1480 } 1481 ip->ip_dst = ipaddr.sin_addr; 1482 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1483 sizeof(struct in_addr)); 1484 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1485 /* 1486 * Let ip_intr's mcast routing check handle mcast pkts 1487 */ 1488 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1489 break; 1490 1491 case IPOPT_RR: 1492 #ifdef IPSTEALTH 1493 if (ipstealth && pass == 0) 1494 break; 1495 #endif 1496 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1497 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1498 goto bad; 1499 } 1500 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1501 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1502 goto bad; 1503 } 1504 /* 1505 * If no space remains, ignore. 1506 */ 1507 off--; /* 0 origin */ 1508 if (off > optlen - (int)sizeof(struct in_addr)) 1509 break; 1510 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1511 sizeof(ipaddr.sin_addr)); 1512 /* 1513 * locate outgoing interface; if we're the destination, 1514 * use the incoming interface (should be same). 1515 */ 1516 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1517 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1518 type = ICMP_UNREACH; 1519 code = ICMP_UNREACH_HOST; 1520 goto bad; 1521 } 1522 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1523 sizeof(struct in_addr)); 1524 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1525 break; 1526 1527 case IPOPT_TS: 1528 #ifdef IPSTEALTH 1529 if (ipstealth && pass == 0) 1530 break; 1531 #endif 1532 code = cp - (u_char *)ip; 1533 if (optlen < 4 || optlen > 40) { 1534 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1535 goto bad; 1536 } 1537 if ((off = cp[IPOPT_OFFSET]) < 5) { 1538 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1539 goto bad; 1540 } 1541 if (off > optlen - (int)sizeof(int32_t)) { 1542 cp[IPOPT_OFFSET + 1] += (1 << 4); 1543 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1544 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1545 goto bad; 1546 } 1547 break; 1548 } 1549 off--; /* 0 origin */ 1550 sin = (struct in_addr *)(cp + off); 1551 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1552 1553 case IPOPT_TS_TSONLY: 1554 break; 1555 1556 case IPOPT_TS_TSANDADDR: 1557 if (off + sizeof(n_time) + 1558 sizeof(struct in_addr) > optlen) { 1559 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1560 goto bad; 1561 } 1562 ipaddr.sin_addr = dst; 1563 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1564 m->m_pkthdr.rcvif); 1565 if (ia == 0) 1566 continue; 1567 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1568 sizeof(struct in_addr)); 1569 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1570 off += sizeof(struct in_addr); 1571 break; 1572 1573 case IPOPT_TS_PRESPEC: 1574 if (off + sizeof(n_time) + 1575 sizeof(struct in_addr) > optlen) { 1576 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1577 goto bad; 1578 } 1579 (void)memcpy(&ipaddr.sin_addr, sin, 1580 sizeof(struct in_addr)); 1581 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1582 continue; 1583 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1584 off += sizeof(struct in_addr); 1585 break; 1586 1587 default: 1588 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1589 goto bad; 1590 } 1591 ntime = iptime(); 1592 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1593 cp[IPOPT_OFFSET] += sizeof(n_time); 1594 } 1595 } 1596 if (forward && ipforwarding) { 1597 ip_forward(m, 1, next_hop); 1598 return (1); 1599 } 1600 return (0); 1601 bad: 1602 icmp_error(m, type, code, 0, 0); 1603 ipstat.ips_badoptions++; 1604 return (1); 1605 } 1606 1607 /* 1608 * Given address of next destination (final or next hop), 1609 * return internet address info of interface to be used to get there. 1610 */ 1611 struct in_ifaddr * 1612 ip_rtaddr(dst) 1613 struct in_addr dst; 1614 { 1615 struct route sro; 1616 struct sockaddr_in *sin; 1617 struct in_ifaddr *ifa; 1618 1619 bzero(&sro, sizeof(sro)); 1620 sin = (struct sockaddr_in *)&sro.ro_dst; 1621 sin->sin_family = AF_INET; 1622 sin->sin_len = sizeof(*sin); 1623 sin->sin_addr = dst; 1624 rtalloc_ign(&sro, RTF_CLONING); 1625 1626 if (sro.ro_rt == NULL) 1627 return ((struct in_ifaddr *)0); 1628 1629 ifa = ifatoia(sro.ro_rt->rt_ifa); 1630 RTFREE(sro.ro_rt); 1631 return ifa; 1632 } 1633 1634 /* 1635 * Save incoming source route for use in replies, 1636 * to be picked up later by ip_srcroute if the receiver is interested. 1637 */ 1638 static void 1639 save_rte(option, dst) 1640 u_char *option; 1641 struct in_addr dst; 1642 { 1643 unsigned olen; 1644 1645 olen = option[IPOPT_OLEN]; 1646 #ifdef DIAGNOSTIC 1647 if (ipprintfs) 1648 printf("save_rte: olen %d\n", olen); 1649 #endif 1650 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1651 return; 1652 bcopy(option, ip_srcrt.srcopt, olen); 1653 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1654 ip_srcrt.dst = dst; 1655 } 1656 1657 /* 1658 * Retrieve incoming source route for use in replies, 1659 * in the same form used by setsockopt. 1660 * The first hop is placed before the options, will be removed later. 1661 */ 1662 struct mbuf * 1663 ip_srcroute() 1664 { 1665 register struct in_addr *p, *q; 1666 register struct mbuf *m; 1667 1668 if (ip_nhops == 0) 1669 return ((struct mbuf *)0); 1670 m = m_get(M_DONTWAIT, MT_HEADER); 1671 if (m == 0) 1672 return ((struct mbuf *)0); 1673 1674 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1675 1676 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1677 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1678 OPTSIZ; 1679 #ifdef DIAGNOSTIC 1680 if (ipprintfs) 1681 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1682 #endif 1683 1684 /* 1685 * First save first hop for return route 1686 */ 1687 p = &ip_srcrt.route[ip_nhops - 1]; 1688 *(mtod(m, struct in_addr *)) = *p--; 1689 #ifdef DIAGNOSTIC 1690 if (ipprintfs) 1691 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1692 #endif 1693 1694 /* 1695 * Copy option fields and padding (nop) to mbuf. 1696 */ 1697 ip_srcrt.nop = IPOPT_NOP; 1698 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1699 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1700 &ip_srcrt.nop, OPTSIZ); 1701 q = (struct in_addr *)(mtod(m, caddr_t) + 1702 sizeof(struct in_addr) + OPTSIZ); 1703 #undef OPTSIZ 1704 /* 1705 * Record return path as an IP source route, 1706 * reversing the path (pointers are now aligned). 1707 */ 1708 while (p >= ip_srcrt.route) { 1709 #ifdef DIAGNOSTIC 1710 if (ipprintfs) 1711 printf(" %lx", (u_long)ntohl(q->s_addr)); 1712 #endif 1713 *q++ = *p--; 1714 } 1715 /* 1716 * Last hop goes to final destination. 1717 */ 1718 *q = ip_srcrt.dst; 1719 #ifdef DIAGNOSTIC 1720 if (ipprintfs) 1721 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1722 #endif 1723 return (m); 1724 } 1725 1726 /* 1727 * Strip out IP options, at higher 1728 * level protocol in the kernel. 1729 * Second argument is buffer to which options 1730 * will be moved, and return value is their length. 1731 * XXX should be deleted; last arg currently ignored. 1732 */ 1733 void 1734 ip_stripoptions(m, mopt) 1735 register struct mbuf *m; 1736 struct mbuf *mopt; 1737 { 1738 register int i; 1739 struct ip *ip = mtod(m, struct ip *); 1740 register caddr_t opts; 1741 int olen; 1742 1743 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1744 opts = (caddr_t)(ip + 1); 1745 i = m->m_len - (sizeof (struct ip) + olen); 1746 bcopy(opts + olen, opts, (unsigned)i); 1747 m->m_len -= olen; 1748 if (m->m_flags & M_PKTHDR) 1749 m->m_pkthdr.len -= olen; 1750 ip->ip_v = IPVERSION; 1751 ip->ip_hl = sizeof(struct ip) >> 2; 1752 } 1753 1754 u_char inetctlerrmap[PRC_NCMDS] = { 1755 0, 0, 0, 0, 1756 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1757 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1758 EMSGSIZE, EHOSTUNREACH, 0, 0, 1759 0, 0, EHOSTUNREACH, 0, 1760 ENOPROTOOPT, ECONNREFUSED 1761 }; 1762 1763 /* 1764 * Forward a packet. If some error occurs return the sender 1765 * an icmp packet. Note we can't always generate a meaningful 1766 * icmp message because icmp doesn't have a large enough repertoire 1767 * of codes and types. 1768 * 1769 * If not forwarding, just drop the packet. This could be confusing 1770 * if ipforwarding was zero but some routing protocol was advancing 1771 * us as a gateway to somewhere. However, we must let the routing 1772 * protocol deal with that. 1773 * 1774 * The srcrt parameter indicates whether the packet is being forwarded 1775 * via a source route. 1776 */ 1777 static void 1778 ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop) 1779 { 1780 struct ip *ip = mtod(m, struct ip *); 1781 struct in_ifaddr *ia; 1782 int error, type = 0, code = 0; 1783 struct mbuf *mcopy; 1784 n_long dest; 1785 struct in_addr pkt_dst; 1786 struct ifnet *destifp; 1787 #if defined(IPSEC) || defined(FAST_IPSEC) 1788 struct ifnet dummyifp; 1789 #endif 1790 1791 /* 1792 * Cache the destination address of the packet; this may be 1793 * changed by use of 'ipfw fwd'. 1794 */ 1795 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 1796 1797 #ifdef DIAGNOSTIC 1798 if (ipprintfs) 1799 printf("forward: src %lx dst %lx ttl %x\n", 1800 (u_long)ip->ip_src.s_addr, (u_long)pkt_dst.s_addr, 1801 ip->ip_ttl); 1802 #endif 1803 1804 1805 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(pkt_dst) == 0) { 1806 ipstat.ips_cantforward++; 1807 m_freem(m); 1808 return; 1809 } 1810 #ifdef IPSTEALTH 1811 if (!ipstealth) { 1812 #endif 1813 if (ip->ip_ttl <= IPTTLDEC) { 1814 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1815 0, 0); 1816 return; 1817 } 1818 #ifdef IPSTEALTH 1819 } 1820 #endif 1821 1822 if ((ia = ip_rtaddr(pkt_dst)) == 0) { 1823 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1824 return; 1825 } 1826 1827 /* 1828 * Save the IP header and at most 8 bytes of the payload, 1829 * in case we need to generate an ICMP message to the src. 1830 * 1831 * XXX this can be optimized a lot by saving the data in a local 1832 * buffer on the stack (72 bytes at most), and only allocating the 1833 * mbuf if really necessary. The vast majority of the packets 1834 * are forwarded without having to send an ICMP back (either 1835 * because unnecessary, or because rate limited), so we are 1836 * really we are wasting a lot of work here. 1837 * 1838 * We don't use m_copy() because it might return a reference 1839 * to a shared cluster. Both this function and ip_output() 1840 * assume exclusive access to the IP header in `m', so any 1841 * data in a cluster may change before we reach icmp_error(). 1842 */ 1843 MGET(mcopy, M_DONTWAIT, m->m_type); 1844 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1845 /* 1846 * It's probably ok if the pkthdr dup fails (because 1847 * the deep copy of the tag chain failed), but for now 1848 * be conservative and just discard the copy since 1849 * code below may some day want the tags. 1850 */ 1851 m_free(mcopy); 1852 mcopy = NULL; 1853 } 1854 if (mcopy != NULL) { 1855 mcopy->m_len = imin((ip->ip_hl << 2) + 8, 1856 (int)ip->ip_len); 1857 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1858 } 1859 1860 #ifdef IPSTEALTH 1861 if (!ipstealth) { 1862 #endif 1863 ip->ip_ttl -= IPTTLDEC; 1864 #ifdef IPSTEALTH 1865 } 1866 #endif 1867 1868 /* 1869 * If forwarding packet using same interface that it came in on, 1870 * perhaps should send a redirect to sender to shortcut a hop. 1871 * Only send redirect if source is sending directly to us, 1872 * and if packet was not source routed (or has any options). 1873 * Also, don't send redirect if forwarding using a default route 1874 * or a route modified by a redirect. 1875 */ 1876 dest = 0; 1877 if (ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) { 1878 struct sockaddr_in *sin; 1879 struct route ro; 1880 struct rtentry *rt; 1881 1882 bzero(&ro, sizeof(ro)); 1883 sin = (struct sockaddr_in *)&ro.ro_dst; 1884 sin->sin_family = AF_INET; 1885 sin->sin_len = sizeof(*sin); 1886 sin->sin_addr = pkt_dst; 1887 rtalloc_ign(&ro, RTF_CLONING); 1888 1889 rt = ro.ro_rt; 1890 1891 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1892 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1893 ipsendredirects && !srcrt && !next_hop) { 1894 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1895 u_long src = ntohl(ip->ip_src.s_addr); 1896 1897 if (RTA(rt) && 1898 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1899 if (rt->rt_flags & RTF_GATEWAY) 1900 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1901 else 1902 dest = pkt_dst.s_addr; 1903 /* Router requirements says to only send host redirects */ 1904 type = ICMP_REDIRECT; 1905 code = ICMP_REDIRECT_HOST; 1906 #ifdef DIAGNOSTIC 1907 if (ipprintfs) 1908 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1909 #endif 1910 } 1911 } 1912 if (rt) 1913 RTFREE(rt); 1914 } 1915 1916 { 1917 struct m_hdr tag; 1918 1919 if (next_hop) { 1920 /* Pass IPFORWARD info if available */ 1921 1922 tag.mh_type = MT_TAG; 1923 tag.mh_flags = PACKET_TAG_IPFORWARD; 1924 tag.mh_data = (caddr_t)next_hop; 1925 tag.mh_next = m; 1926 tag.mh_nextpkt = NULL; 1927 m = (struct mbuf *)&tag; 1928 } 1929 error = ip_output(m, (struct mbuf *)0, NULL, IP_FORWARDING, 0, NULL); 1930 } 1931 if (error) 1932 ipstat.ips_cantforward++; 1933 else { 1934 ipstat.ips_forward++; 1935 if (type) 1936 ipstat.ips_redirectsent++; 1937 else { 1938 if (mcopy) 1939 m_freem(mcopy); 1940 return; 1941 } 1942 } 1943 if (mcopy == NULL) 1944 return; 1945 destifp = NULL; 1946 1947 switch (error) { 1948 1949 case 0: /* forwarded, but need redirect */ 1950 /* type, code set above */ 1951 break; 1952 1953 case ENETUNREACH: /* shouldn't happen, checked above */ 1954 case EHOSTUNREACH: 1955 case ENETDOWN: 1956 case EHOSTDOWN: 1957 default: 1958 type = ICMP_UNREACH; 1959 code = ICMP_UNREACH_HOST; 1960 break; 1961 1962 case EMSGSIZE: 1963 type = ICMP_UNREACH; 1964 code = ICMP_UNREACH_NEEDFRAG; 1965 #if defined(IPSEC) || defined(FAST_IPSEC) 1966 /* 1967 * If the packet is routed over IPsec tunnel, tell the 1968 * originator the tunnel MTU. 1969 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1970 * XXX quickhack!!! 1971 */ 1972 { 1973 struct secpolicy *sp = NULL; 1974 int ipsecerror; 1975 int ipsechdr; 1976 struct route *ro; 1977 1978 #ifdef IPSEC 1979 sp = ipsec4_getpolicybyaddr(mcopy, 1980 IPSEC_DIR_OUTBOUND, 1981 IP_FORWARDING, 1982 &ipsecerror); 1983 #else /* FAST_IPSEC */ 1984 sp = ipsec_getpolicybyaddr(mcopy, 1985 IPSEC_DIR_OUTBOUND, 1986 IP_FORWARDING, 1987 &ipsecerror); 1988 #endif 1989 if (sp != NULL) { 1990 /* count IPsec header size */ 1991 ipsechdr = ipsec4_hdrsiz(mcopy, 1992 IPSEC_DIR_OUTBOUND, 1993 NULL); 1994 1995 /* 1996 * find the correct route for outer IPv4 1997 * header, compute tunnel MTU. 1998 * 1999 * XXX BUG ALERT 2000 * The "dummyifp" code relies upon the fact 2001 * that icmp_error() touches only ifp->if_mtu. 2002 */ 2003 /*XXX*/ 2004 destifp = NULL; 2005 if (sp->req != NULL 2006 && sp->req->sav != NULL 2007 && sp->req->sav->sah != NULL) { 2008 ro = &sp->req->sav->sah->sa_route; 2009 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 2010 dummyifp.if_mtu = 2011 ro->ro_rt->rt_ifp->if_mtu; 2012 dummyifp.if_mtu -= ipsechdr; 2013 destifp = &dummyifp; 2014 } 2015 } 2016 2017 #ifdef IPSEC 2018 key_freesp(sp); 2019 #else /* FAST_IPSEC */ 2020 KEY_FREESP(&sp); 2021 #endif 2022 ipstat.ips_cantfrag++; 2023 break; 2024 } else 2025 #endif /*IPSEC || FAST_IPSEC*/ 2026 destifp = ia->ia_ifp; 2027 #if defined(IPSEC) || defined(FAST_IPSEC) 2028 } 2029 #endif /*IPSEC || FAST_IPSEC*/ 2030 ipstat.ips_cantfrag++; 2031 break; 2032 2033 case ENOBUFS: 2034 /* 2035 * A router should not generate ICMP_SOURCEQUENCH as 2036 * required in RFC1812 Requirements for IP Version 4 Routers. 2037 * Source quench could be a big problem under DoS attacks, 2038 * or if the underlying interface is rate-limited. 2039 * Those who need source quench packets may re-enable them 2040 * via the net.inet.ip.sendsourcequench sysctl. 2041 */ 2042 if (ip_sendsourcequench == 0) { 2043 m_freem(mcopy); 2044 return; 2045 } else { 2046 type = ICMP_SOURCEQUENCH; 2047 code = 0; 2048 } 2049 break; 2050 2051 case EACCES: /* ipfw denied packet */ 2052 m_freem(mcopy); 2053 return; 2054 } 2055 icmp_error(mcopy, type, code, dest, destifp); 2056 } 2057 2058 void 2059 ip_savecontrol(inp, mp, ip, m) 2060 register struct inpcb *inp; 2061 register struct mbuf **mp; 2062 register struct ip *ip; 2063 register struct mbuf *m; 2064 { 2065 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2066 struct timeval tv; 2067 2068 microtime(&tv); 2069 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2070 SCM_TIMESTAMP, SOL_SOCKET); 2071 if (*mp) 2072 mp = &(*mp)->m_next; 2073 } 2074 if (inp->inp_flags & INP_RECVDSTADDR) { 2075 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2076 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2077 if (*mp) 2078 mp = &(*mp)->m_next; 2079 } 2080 if (inp->inp_flags & INP_RECVTTL) { 2081 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2082 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2083 if (*mp) 2084 mp = &(*mp)->m_next; 2085 } 2086 #ifdef notyet 2087 /* XXX 2088 * Moving these out of udp_input() made them even more broken 2089 * than they already were. 2090 */ 2091 /* options were tossed already */ 2092 if (inp->inp_flags & INP_RECVOPTS) { 2093 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2094 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2095 if (*mp) 2096 mp = &(*mp)->m_next; 2097 } 2098 /* ip_srcroute doesn't do what we want here, need to fix */ 2099 if (inp->inp_flags & INP_RECVRETOPTS) { 2100 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2101 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2102 if (*mp) 2103 mp = &(*mp)->m_next; 2104 } 2105 #endif 2106 if (inp->inp_flags & INP_RECVIF) { 2107 struct ifnet *ifp; 2108 struct sdlbuf { 2109 struct sockaddr_dl sdl; 2110 u_char pad[32]; 2111 } sdlbuf; 2112 struct sockaddr_dl *sdp; 2113 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2114 2115 if (((ifp = m->m_pkthdr.rcvif)) 2116 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2117 sdp = (struct sockaddr_dl *) 2118 (ifaddr_byindex(ifp->if_index)->ifa_addr); 2119 /* 2120 * Change our mind and don't try copy. 2121 */ 2122 if ((sdp->sdl_family != AF_LINK) 2123 || (sdp->sdl_len > sizeof(sdlbuf))) { 2124 goto makedummy; 2125 } 2126 bcopy(sdp, sdl2, sdp->sdl_len); 2127 } else { 2128 makedummy: 2129 sdl2->sdl_len 2130 = offsetof(struct sockaddr_dl, sdl_data[0]); 2131 sdl2->sdl_family = AF_LINK; 2132 sdl2->sdl_index = 0; 2133 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2134 } 2135 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2136 IP_RECVIF, IPPROTO_IP); 2137 if (*mp) 2138 mp = &(*mp)->m_next; 2139 } 2140 } 2141 2142 /* 2143 * XXX these routines are called from the upper part of the kernel. 2144 * They need to be locked when we remove Giant. 2145 * 2146 * They could also be moved to ip_mroute.c, since all the RSVP 2147 * handling is done there already. 2148 */ 2149 static int ip_rsvp_on; 2150 struct socket *ip_rsvpd; 2151 int 2152 ip_rsvp_init(struct socket *so) 2153 { 2154 if (so->so_type != SOCK_RAW || 2155 so->so_proto->pr_protocol != IPPROTO_RSVP) 2156 return EOPNOTSUPP; 2157 2158 if (ip_rsvpd != NULL) 2159 return EADDRINUSE; 2160 2161 ip_rsvpd = so; 2162 /* 2163 * This may seem silly, but we need to be sure we don't over-increment 2164 * the RSVP counter, in case something slips up. 2165 */ 2166 if (!ip_rsvp_on) { 2167 ip_rsvp_on = 1; 2168 rsvp_on++; 2169 } 2170 2171 return 0; 2172 } 2173 2174 int 2175 ip_rsvp_done(void) 2176 { 2177 ip_rsvpd = NULL; 2178 /* 2179 * This may seem silly, but we need to be sure we don't over-decrement 2180 * the RSVP counter, in case something slips up. 2181 */ 2182 if (ip_rsvp_on) { 2183 ip_rsvp_on = 0; 2184 rsvp_on--; 2185 } 2186 return 0; 2187 } 2188 2189 void 2190 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 2191 { 2192 if (rsvp_input_p) { /* call the real one if loaded */ 2193 rsvp_input_p(m, off); 2194 return; 2195 } 2196 2197 /* Can still get packets with rsvp_on = 0 if there is a local member 2198 * of the group to which the RSVP packet is addressed. But in this 2199 * case we want to throw the packet away. 2200 */ 2201 2202 if (!rsvp_on) { 2203 m_freem(m); 2204 return; 2205 } 2206 2207 if (ip_rsvpd != NULL) { 2208 rip_input(m, off); 2209 return; 2210 } 2211 /* Drop the packet */ 2212 m_freem(m); 2213 }
Cache object: 876997b07aef21087f4eda557aaaf0be
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