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 #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 static 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 * One deep route cache for ip forwarding. This is done 217 * very inefficiently. We don't care as it's about to be 218 * replaced by something better. 219 */ 220 static struct rtcache { 221 struct route rc_ro; /* most recently used route */ 222 struct mtx rc_mtx; /* update lock for cache */ 223 } ip_fwdcache; 224 225 #define RTCACHE_LOCK() mtx_lock(&ip_fwdcache.rc_mtx) 226 #define RTCACHE_UNLOCK() mtx_unlock(&ip_fwdcache.rc_mtx) 227 #define RTCACHE_LOCK_INIT() \ 228 mtx_init(&ip_fwdcache.rc_mtx, "route cache", NULL, MTX_DEF) 229 #define RTCACHE_LOCK_ASSERT() mtx_assert(&ip_fwdcache.rc_mtx, MA_OWNED) 230 231 /* 232 * Get a copy of the current route cache contents. 233 */ 234 #define RTCACHE_GET(_ro) do { \ 235 struct rtentry *rt; \ 236 RTCACHE_LOCK(); \ 237 *(_ro) = ip_fwdcache.rc_ro; \ 238 if ((rt = (_ro)->ro_rt) != NULL) { \ 239 RT_LOCK(rt); \ 240 rt->rt_refcnt++; \ 241 RT_UNLOCK(rt); \ 242 } \ 243 RTCACHE_UNLOCK(); \ 244 } while (0) 245 246 /* 247 * Update the cache contents. 248 */ 249 #define RTCACHE_UPDATE(_ro) do { \ 250 struct rtentry *rt; \ 251 RTCACHE_LOCK(); \ 252 rt = ip_fwdcache.rc_ro.ro_rt; \ 253 if ((_ro)->ro_rt != rt) { \ 254 ip_fwdcache.rc_ro = *(_ro); \ 255 if (rt) \ 256 RTFREE(rt); \ 257 } \ 258 RTCACHE_UNLOCK(); \ 259 } while (0) 260 261 /* 262 * XXX this is ugly -- the following two global variables are 263 * used to store packet state while it travels through the stack. 264 * Note that the code even makes assumptions on the size and 265 * alignment of fields inside struct ip_srcrt so e.g. adding some 266 * fields will break the code. This needs to be fixed. 267 * 268 * We need to save the IP options in case a protocol wants to respond 269 * to an incoming packet over the same route if the packet got here 270 * using IP source routing. This allows connection establishment and 271 * maintenance when the remote end is on a network that is not known 272 * to us. 273 */ 274 static int ip_nhops = 0; 275 static struct ip_srcrt { 276 struct in_addr dst; /* final destination */ 277 char nop; /* one NOP to align */ 278 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 279 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 280 } ip_srcrt; 281 282 static void save_rte(u_char *, struct in_addr); 283 static int ip_dooptions(struct mbuf *m, int, 284 struct sockaddr_in *next_hop); 285 static void ip_forward(struct mbuf *m, struct route *, int srcrt, 286 struct sockaddr_in *next_hop); 287 static void ip_freef(struct ipqhead *, struct ipq *); 288 static struct mbuf *ip_reass(struct mbuf *, struct ipqhead *, 289 struct ipq *, u_int32_t *, u_int16_t *); 290 291 /* 292 * IP initialization: fill in IP protocol switch table. 293 * All protocols not implemented in kernel go to raw IP protocol handler. 294 */ 295 void 296 ip_init() 297 { 298 register struct protosw *pr; 299 register int i; 300 301 TAILQ_INIT(&in_ifaddrhead); 302 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 303 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 304 if (pr == 0) 305 panic("ip_init"); 306 for (i = 0; i < IPPROTO_MAX; i++) 307 ip_protox[i] = pr - inetsw; 308 for (pr = inetdomain.dom_protosw; 309 pr < inetdomain.dom_protoswNPROTOSW; pr++) 310 if (pr->pr_domain->dom_family == PF_INET && 311 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 312 ip_protox[pr->pr_protocol] = pr - inetsw; 313 314 #ifdef PFIL_HOOKS 315 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 316 inet_pfil_hook.ph_af = AF_INET; 317 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) 318 printf("%s: WARNING: unable to register pfil hook, " 319 "error %d\n", __func__, i); 320 #endif /* PFIL_HOOKS */ 321 322 IPQ_LOCK_INIT(); 323 for (i = 0; i < IPREASS_NHASH; i++) 324 TAILQ_INIT(&ipq[i]); 325 326 bzero(&ip_fwdcache, sizeof(ip_fwdcache)); 327 RTCACHE_LOCK_INIT(); 328 329 maxnipq = nmbclusters / 32; 330 maxfragsperpacket = 16; 331 332 #ifndef RANDOM_IP_ID 333 ip_id = time_second & 0xffff; 334 #endif 335 ipintrq.ifq_maxlen = ipqmaxlen; 336 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF); 337 netisr_register(NETISR_IP, ip_input, &ipintrq); 338 } 339 340 /* 341 * Invalidate any cached route used for forwarding. 342 */ 343 void 344 ip_forward_cacheinval(void) 345 { 346 struct rtentry *rt; 347 348 RTCACHE_LOCK(); 349 rt = ip_fwdcache.rc_ro.ro_rt; 350 ip_fwdcache.rc_ro.ro_rt = 0; 351 if (rt != NULL) 352 RTFREE(rt); 353 RTCACHE_UNLOCK(); 354 } 355 356 /* 357 * Ip input routine. Checksum and byte swap header. If fragmented 358 * try to reassemble. Process options. Pass to next level. 359 */ 360 void 361 ip_input(struct mbuf *m) 362 { 363 struct ip *ip; 364 struct ipq *fp; 365 struct in_ifaddr *ia = NULL; 366 struct ifaddr *ifa; 367 int i, hlen, checkif; 368 u_short sum; 369 struct in_addr pkt_dst; 370 u_int32_t divert_info = 0; /* packet divert/tee info */ 371 struct ip_fw_args args; 372 struct route cro; /* copy of cached route */ 373 int srcrt = 0; /* forward by ``src routing'' */ 374 #ifdef PFIL_HOOKS 375 struct in_addr odst; /* original dst address */ 376 #endif 377 #ifdef FAST_IPSEC 378 struct m_tag *mtag; 379 struct tdb_ident *tdbi; 380 struct secpolicy *sp; 381 int s, error; 382 #endif /* FAST_IPSEC */ 383 384 args.eh = NULL; 385 args.oif = NULL; 386 args.rule = NULL; 387 args.divert_rule = 0; /* divert cookie */ 388 args.next_hop = NULL; 389 390 /* Grab info from MT_TAG mbufs prepended to the chain. */ 391 for (; m && m->m_type == MT_TAG; m = m->m_next) { 392 switch(m->_m_tag_id) { 393 default: 394 printf("ip_input: unrecognised MT_TAG tag %d\n", 395 m->_m_tag_id); 396 break; 397 398 case PACKET_TAG_DUMMYNET: 399 args.rule = ((struct dn_pkt *)m)->rule; 400 break; 401 402 case PACKET_TAG_DIVERT: 403 args.divert_rule = (intptr_t)m->m_hdr.mh_data & 0xffff; 404 break; 405 406 case PACKET_TAG_IPFORWARD: 407 args.next_hop = (struct sockaddr_in *)m->m_hdr.mh_data; 408 break; 409 } 410 } 411 412 M_ASSERTPKTHDR(m); 413 414 if (args.rule) { /* dummynet already filtered us */ 415 ip = mtod(m, struct ip *); 416 hlen = ip->ip_hl << 2; 417 goto iphack ; 418 } 419 420 ipstat.ips_total++; 421 422 if (m->m_pkthdr.len < sizeof(struct ip)) 423 goto tooshort; 424 425 if (m->m_len < sizeof (struct ip) && 426 (m = m_pullup(m, sizeof (struct ip))) == 0) { 427 ipstat.ips_toosmall++; 428 return; 429 } 430 ip = mtod(m, struct ip *); 431 432 if (ip->ip_v != IPVERSION) { 433 ipstat.ips_badvers++; 434 goto bad; 435 } 436 437 hlen = ip->ip_hl << 2; 438 if (hlen < sizeof(struct ip)) { /* minimum header length */ 439 ipstat.ips_badhlen++; 440 goto bad; 441 } 442 if (hlen > m->m_len) { 443 if ((m = m_pullup(m, hlen)) == 0) { 444 ipstat.ips_badhlen++; 445 return; 446 } 447 ip = mtod(m, struct ip *); 448 } 449 450 /* 127/8 must not appear on wire - RFC1122 */ 451 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 452 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 453 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 454 ipstat.ips_badaddr++; 455 goto bad; 456 } 457 } 458 459 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 460 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 461 } else { 462 if (hlen == sizeof(struct ip)) { 463 sum = in_cksum_hdr(ip); 464 } else { 465 sum = in_cksum(m, hlen); 466 } 467 } 468 if (sum) { 469 ipstat.ips_badsum++; 470 goto bad; 471 } 472 473 /* 474 * Convert fields to host representation. 475 */ 476 ip->ip_len = ntohs(ip->ip_len); 477 if (ip->ip_len < hlen) { 478 ipstat.ips_badlen++; 479 goto bad; 480 } 481 ip->ip_off = ntohs(ip->ip_off); 482 483 /* 484 * Check that the amount of data in the buffers 485 * is as at least much as the IP header would have us expect. 486 * Trim mbufs if longer than we expect. 487 * Drop packet if shorter than we expect. 488 */ 489 if (m->m_pkthdr.len < ip->ip_len) { 490 tooshort: 491 ipstat.ips_tooshort++; 492 goto bad; 493 } 494 if (m->m_pkthdr.len > ip->ip_len) { 495 if (m->m_len == m->m_pkthdr.len) { 496 m->m_len = ip->ip_len; 497 m->m_pkthdr.len = ip->ip_len; 498 } else 499 m_adj(m, ip->ip_len - m->m_pkthdr.len); 500 } 501 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF) 502 /* 503 * Bypass packet filtering for packets from a tunnel (gif). 504 */ 505 if (ipsec_getnhist(m)) 506 goto pass; 507 #endif 508 #if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF) 509 /* 510 * Bypass packet filtering for packets from a tunnel (gif). 511 */ 512 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL) 513 goto pass; 514 #endif 515 516 /* 517 * IpHack's section. 518 * Right now when no processing on packet has done 519 * and it is still fresh out of network we do our black 520 * deals with it. 521 * - Firewall: deny/allow/divert 522 * - Xlate: translate packet's addr/port (NAT). 523 * - Pipe: pass pkt through dummynet. 524 * - Wrap: fake packet's addr/port <unimpl.> 525 * - Encapsulate: put it in another IP and send out. <unimp.> 526 */ 527 528 iphack: 529 530 #ifdef PFIL_HOOKS 531 /* 532 * Run through list of hooks for input packets. 533 * 534 * NB: Beware of the destination address changing (e.g. 535 * by NAT rewriting). When this happens, tell 536 * ip_forward to do the right thing. 537 */ 538 odst = ip->ip_dst; 539 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, 540 PFIL_IN) != 0) 541 return; 542 if (m == NULL) /* consumed by filter */ 543 return; 544 ip = mtod(m, struct ip *); 545 srcrt = (odst.s_addr != ip->ip_dst.s_addr); 546 #endif /* PFIL_HOOKS */ 547 548 if (fw_enable && IPFW_LOADED) { 549 /* 550 * If we've been forwarded from the output side, then 551 * skip the firewall a second time 552 */ 553 if (args.next_hop) 554 goto ours; 555 556 args.m = m; 557 i = ip_fw_chk_ptr(&args); 558 m = args.m; 559 560 if ( (i & IP_FW_PORT_DENY_FLAG) || m == NULL) { /* drop */ 561 if (m) 562 m_freem(m); 563 return; 564 } 565 ip = mtod(m, struct ip *); /* just in case m changed */ 566 if (i == 0 && args.next_hop == NULL) /* common case */ 567 goto pass; 568 if (DUMMYNET_LOADED && (i & IP_FW_PORT_DYNT_FLAG) != 0) { 569 /* Send packet to the appropriate pipe */ 570 ip_dn_io_ptr(m, i&0xffff, DN_TO_IP_IN, &args); 571 return; 572 } 573 #ifdef IPDIVERT 574 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 575 /* Divert or tee packet */ 576 divert_info = i; 577 goto ours; 578 } 579 #endif 580 if (i == 0 && args.next_hop != NULL) 581 goto pass; 582 /* 583 * if we get here, the packet must be dropped 584 */ 585 m_freem(m); 586 return; 587 } 588 pass: 589 590 /* 591 * Process options and, if not destined for us, 592 * ship it on. ip_dooptions returns 1 when an 593 * error was detected (causing an icmp message 594 * to be sent and the original packet to be freed). 595 */ 596 ip_nhops = 0; /* for source routed packets */ 597 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0, args.next_hop)) 598 return; 599 600 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 601 * matter if it is destined to another node, or whether it is 602 * a multicast one, RSVP wants it! and prevents it from being forwarded 603 * anywhere else. Also checks if the rsvp daemon is running before 604 * grabbing the packet. 605 */ 606 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 607 goto ours; 608 609 /* 610 * Check our list of addresses, to see if the packet is for us. 611 * If we don't have any addresses, assume any unicast packet 612 * we receive might be for us (and let the upper layers deal 613 * with it). 614 */ 615 if (TAILQ_EMPTY(&in_ifaddrhead) && 616 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 617 goto ours; 618 619 /* 620 * Cache the destination address of the packet; this may be 621 * changed by use of 'ipfw fwd'. 622 */ 623 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst; 624 625 /* 626 * Enable a consistency check between the destination address 627 * and the arrival interface for a unicast packet (the RFC 1122 628 * strong ES model) if IP forwarding is disabled and the packet 629 * is not locally generated and the packet is not subject to 630 * 'ipfw fwd'. 631 * 632 * XXX - Checking also should be disabled if the destination 633 * address is ipnat'ed to a different interface. 634 * 635 * XXX - Checking is incompatible with IP aliases added 636 * to the loopback interface instead of the interface where 637 * the packets are received. 638 */ 639 checkif = ip_checkinterface && (ipforwarding == 0) && 640 m->m_pkthdr.rcvif != NULL && 641 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 642 (args.next_hop == NULL); 643 644 /* 645 * Check for exact addresses in the hash bucket. 646 */ 647 LIST_FOREACH(ia, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 648 /* 649 * If the address matches, verify that the packet 650 * arrived via the correct interface if checking is 651 * enabled. 652 */ 653 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 654 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 655 goto ours; 656 } 657 /* 658 * Check for broadcast addresses. 659 * 660 * Only accept broadcast packets that arrive via the matching 661 * interface. Reception of forwarded directed broadcasts would 662 * be handled via ip_forward() and ether_output() with the loopback 663 * into the stack for SIMPLEX interfaces handled by ether_output(). 664 */ 665 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 666 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 667 if (ifa->ifa_addr->sa_family != AF_INET) 668 continue; 669 ia = ifatoia(ifa); 670 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 671 pkt_dst.s_addr) 672 goto ours; 673 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 674 goto ours; 675 #ifdef BOOTP_COMPAT 676 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 677 goto ours; 678 #endif 679 } 680 } 681 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 682 struct in_multi *inm; 683 if (ip_mrouter) { 684 /* 685 * If we are acting as a multicast router, all 686 * incoming multicast packets are passed to the 687 * kernel-level multicast forwarding function. 688 * The packet is returned (relatively) intact; if 689 * ip_mforward() returns a non-zero value, the packet 690 * must be discarded, else it may be accepted below. 691 */ 692 if (ip_mforward && 693 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 694 ipstat.ips_cantforward++; 695 m_freem(m); 696 return; 697 } 698 699 /* 700 * The process-level routing daemon needs to receive 701 * all multicast IGMP packets, whether or not this 702 * host belongs to their destination groups. 703 */ 704 if (ip->ip_p == IPPROTO_IGMP) 705 goto ours; 706 ipstat.ips_forward++; 707 } 708 /* 709 * See if we belong to the destination multicast group on the 710 * arrival interface. 711 */ 712 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 713 if (inm == NULL) { 714 ipstat.ips_notmember++; 715 m_freem(m); 716 return; 717 } 718 goto ours; 719 } 720 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 721 goto ours; 722 if (ip->ip_dst.s_addr == INADDR_ANY) 723 goto ours; 724 725 /* 726 * FAITH(Firewall Aided Internet Translator) 727 */ 728 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 729 if (ip_keepfaith) { 730 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 731 goto ours; 732 } 733 m_freem(m); 734 return; 735 } 736 737 /* 738 * Not for us; forward if possible and desirable. 739 */ 740 if (ipforwarding == 0) { 741 ipstat.ips_cantforward++; 742 m_freem(m); 743 } else { 744 #ifdef IPSEC 745 /* 746 * Enforce inbound IPsec SPD. 747 */ 748 if (ipsec4_in_reject(m, NULL)) { 749 ipsecstat.in_polvio++; 750 goto bad; 751 } 752 #endif /* IPSEC */ 753 #ifdef FAST_IPSEC 754 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 755 s = splnet(); 756 if (mtag != NULL) { 757 tdbi = (struct tdb_ident *)(mtag + 1); 758 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 759 } else { 760 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 761 IP_FORWARDING, &error); 762 } 763 if (sp == NULL) { /* NB: can happen if error */ 764 splx(s); 765 /*XXX error stat???*/ 766 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/ 767 goto bad; 768 } 769 770 /* 771 * Check security policy against packet attributes. 772 */ 773 error = ipsec_in_reject(sp, m); 774 KEY_FREESP(&sp); 775 splx(s); 776 if (error) { 777 ipstat.ips_cantforward++; 778 goto bad; 779 } 780 #endif /* FAST_IPSEC */ 781 RTCACHE_GET(&cro); 782 ip_forward(m, &cro, srcrt, args.next_hop); 783 } 784 return; 785 786 ours: 787 #ifdef IPSTEALTH 788 /* 789 * IPSTEALTH: Process non-routing options only 790 * if the packet is destined for us. 791 */ 792 if (ipstealth && hlen > sizeof (struct ip) && 793 ip_dooptions(m, 1, args.next_hop)) 794 return; 795 #endif /* IPSTEALTH */ 796 797 /* Count the packet in the ip address stats */ 798 if (ia != NULL) { 799 ia->ia_ifa.if_ipackets++; 800 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 801 } 802 803 /* 804 * If offset or IP_MF are set, must reassemble. 805 * Otherwise, nothing need be done. 806 * (We could look in the reassembly queue to see 807 * if the packet was previously fragmented, 808 * but it's not worth the time; just let them time out.) 809 */ 810 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 811 812 /* If maxnipq is 0, never accept fragments. */ 813 if (maxnipq == 0) { 814 ipstat.ips_fragments++; 815 ipstat.ips_fragdropped++; 816 goto bad; 817 } 818 819 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 820 IPQ_LOCK(); 821 /* 822 * Look for queue of fragments 823 * of this datagram. 824 */ 825 TAILQ_FOREACH(fp, &ipq[sum], ipq_list) 826 if (ip->ip_id == fp->ipq_id && 827 ip->ip_src.s_addr == fp->ipq_src.s_addr && 828 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 829 #ifdef MAC 830 mac_fragment_match(m, fp) && 831 #endif 832 ip->ip_p == fp->ipq_p) 833 goto found; 834 835 fp = NULL; 836 837 /* 838 * Enforce upper bound on number of fragmented packets 839 * for which we attempt reassembly; 840 * If maxnipq is -1, accept all fragments without limitation. 841 */ 842 if ((nipq > maxnipq) && (maxnipq > 0)) { 843 /* 844 * drop something from the tail of the current queue 845 * before proceeding further 846 */ 847 struct ipq *q = TAILQ_LAST(&ipq[sum], ipqhead); 848 if (q == NULL) { /* gak */ 849 for (i = 0; i < IPREASS_NHASH; i++) { 850 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 851 if (r) { 852 ipstat.ips_fragtimeout += r->ipq_nfrags; 853 ip_freef(&ipq[i], r); 854 break; 855 } 856 } 857 } else { 858 ipstat.ips_fragtimeout += q->ipq_nfrags; 859 ip_freef(&ipq[sum], q); 860 } 861 } 862 found: 863 /* 864 * Adjust ip_len to not reflect header, 865 * convert offset of this to bytes. 866 */ 867 ip->ip_len -= hlen; 868 if (ip->ip_off & IP_MF) { 869 /* 870 * Make sure that fragments have a data length 871 * that's a non-zero multiple of 8 bytes. 872 */ 873 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 874 IPQ_UNLOCK(); 875 ipstat.ips_toosmall++; /* XXX */ 876 goto bad; 877 } 878 m->m_flags |= M_FRAG; 879 } else 880 m->m_flags &= ~M_FRAG; 881 ip->ip_off <<= 3; 882 883 /* 884 * Attempt reassembly; if it succeeds, proceed. 885 * ip_reass() will return a different mbuf, and update 886 * the divert info in divert_info and args.divert_rule. 887 */ 888 ipstat.ips_fragments++; 889 m->m_pkthdr.header = ip; 890 m = ip_reass(m, 891 &ipq[sum], fp, &divert_info, &args.divert_rule); 892 IPQ_UNLOCK(); 893 if (m == 0) 894 return; 895 ipstat.ips_reassembled++; 896 ip = mtod(m, struct ip *); 897 /* Get the header length of the reassembled packet */ 898 hlen = ip->ip_hl << 2; 899 #ifdef IPDIVERT 900 /* Restore original checksum before diverting packet */ 901 if (divert_info != 0) { 902 ip->ip_len += hlen; 903 ip->ip_len = htons(ip->ip_len); 904 ip->ip_off = htons(ip->ip_off); 905 ip->ip_sum = 0; 906 if (hlen == sizeof(struct ip)) 907 ip->ip_sum = in_cksum_hdr(ip); 908 else 909 ip->ip_sum = in_cksum(m, hlen); 910 ip->ip_off = ntohs(ip->ip_off); 911 ip->ip_len = ntohs(ip->ip_len); 912 ip->ip_len -= hlen; 913 } 914 #endif 915 } else 916 ip->ip_len -= hlen; 917 918 #ifdef IPDIVERT 919 /* 920 * Divert or tee packet to the divert protocol if required. 921 */ 922 if (divert_info != 0) { 923 struct mbuf *clone = NULL; 924 925 /* Clone packet if we're doing a 'tee' */ 926 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 927 clone = m_dup(m, M_DONTWAIT); 928 929 /* Restore packet header fields to original values */ 930 ip->ip_len += hlen; 931 ip->ip_len = htons(ip->ip_len); 932 ip->ip_off = htons(ip->ip_off); 933 934 /* Deliver packet to divert input routine */ 935 divert_packet(m, 1, divert_info & 0xffff, args.divert_rule); 936 ipstat.ips_delivered++; 937 938 /* If 'tee', continue with original packet */ 939 if (clone == NULL) 940 return; 941 m = clone; 942 ip = mtod(m, struct ip *); 943 ip->ip_len += hlen; 944 /* 945 * Jump backwards to complete processing of the 946 * packet. But first clear divert_info to avoid 947 * entering this block again. 948 * We do not need to clear args.divert_rule 949 * or args.next_hop as they will not be used. 950 */ 951 divert_info = 0; 952 goto pass; 953 } 954 #endif 955 956 #ifdef IPSEC 957 /* 958 * enforce IPsec policy checking if we are seeing last header. 959 * note that we do not visit this with protocols with pcb layer 960 * code - like udp/tcp/raw ip. 961 */ 962 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 963 ipsec4_in_reject(m, NULL)) { 964 ipsecstat.in_polvio++; 965 goto bad; 966 } 967 #endif 968 #if FAST_IPSEC 969 /* 970 * enforce IPsec policy checking if we are seeing last header. 971 * note that we do not visit this with protocols with pcb layer 972 * code - like udp/tcp/raw ip. 973 */ 974 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) { 975 /* 976 * Check if the packet has already had IPsec processing 977 * done. If so, then just pass it along. This tag gets 978 * set during AH, ESP, etc. input handling, before the 979 * packet is returned to the ip input queue for delivery. 980 */ 981 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 982 s = splnet(); 983 if (mtag != NULL) { 984 tdbi = (struct tdb_ident *)(mtag + 1); 985 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND); 986 } else { 987 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND, 988 IP_FORWARDING, &error); 989 } 990 if (sp != NULL) { 991 /* 992 * Check security policy against packet attributes. 993 */ 994 error = ipsec_in_reject(sp, m); 995 KEY_FREESP(&sp); 996 } else { 997 /* XXX error stat??? */ 998 error = EINVAL; 999 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/ 1000 goto bad; 1001 } 1002 splx(s); 1003 if (error) 1004 goto bad; 1005 } 1006 #endif /* FAST_IPSEC */ 1007 1008 /* 1009 * Switch out to protocol's input routine. 1010 */ 1011 ipstat.ips_delivered++; 1012 if (args.next_hop && ip->ip_p == IPPROTO_TCP) { 1013 /* TCP needs IPFORWARD info if available */ 1014 struct m_hdr tag; 1015 1016 tag.mh_type = MT_TAG; 1017 tag.mh_flags = PACKET_TAG_IPFORWARD; 1018 tag.mh_data = (caddr_t)args.next_hop; 1019 tag.mh_next = m; 1020 1021 (*inetsw[ip_protox[ip->ip_p]].pr_input)( 1022 (struct mbuf *)&tag, hlen); 1023 } else 1024 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 1025 return; 1026 bad: 1027 m_freem(m); 1028 } 1029 1030 /* 1031 * Take incoming datagram fragment and try to reassemble it into 1032 * whole datagram. If a chain for reassembly of this datagram already 1033 * exists, then it is given as fp; otherwise have to make a chain. 1034 * 1035 * When IPDIVERT enabled, keep additional state with each packet that 1036 * tells us if we need to divert or tee the packet we're building. 1037 * In particular, *divinfo includes the port and TEE flag, 1038 * *divert_rule is the number of the matching rule. 1039 */ 1040 1041 static struct mbuf * 1042 ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp, 1043 u_int32_t *divinfo, u_int16_t *divert_rule) 1044 { 1045 struct ip *ip = mtod(m, struct ip *); 1046 register struct mbuf *p, *q, *nq; 1047 struct mbuf *t; 1048 int hlen = ip->ip_hl << 2; 1049 int i, next; 1050 u_int8_t ecn, ecn0; 1051 1052 IPQ_LOCK_ASSERT(); 1053 1054 /* 1055 * Presence of header sizes in mbufs 1056 * would confuse code below. 1057 */ 1058 m->m_data += hlen; 1059 m->m_len -= hlen; 1060 1061 /* 1062 * If first fragment to arrive, create a reassembly queue. 1063 */ 1064 if (fp == NULL) { 1065 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 1066 goto dropfrag; 1067 fp = mtod(t, struct ipq *); 1068 #ifdef MAC 1069 if (mac_init_ipq(fp, M_NOWAIT) != 0) { 1070 m_free(t); 1071 goto dropfrag; 1072 } 1073 mac_create_ipq(m, fp); 1074 #endif 1075 TAILQ_INSERT_HEAD(head, fp, ipq_list); 1076 nipq++; 1077 fp->ipq_nfrags = 1; 1078 fp->ipq_ttl = IPFRAGTTL; 1079 fp->ipq_p = ip->ip_p; 1080 fp->ipq_id = ip->ip_id; 1081 fp->ipq_src = ip->ip_src; 1082 fp->ipq_dst = ip->ip_dst; 1083 fp->ipq_frags = m; 1084 m->m_nextpkt = NULL; 1085 #ifdef IPDIVERT 1086 fp->ipq_div_info = 0; 1087 fp->ipq_div_cookie = 0; 1088 #endif 1089 goto inserted; 1090 } else { 1091 fp->ipq_nfrags++; 1092 #ifdef MAC 1093 mac_update_ipq(m, fp); 1094 #endif 1095 } 1096 1097 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1098 1099 /* 1100 * Handle ECN by comparing this segment with the first one; 1101 * if CE is set, do not lose CE. 1102 * drop if CE and not-ECT are mixed for the same packet. 1103 */ 1104 ecn = ip->ip_tos & IPTOS_ECN_MASK; 1105 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 1106 if (ecn == IPTOS_ECN_CE) { 1107 if (ecn0 == IPTOS_ECN_NOTECT) 1108 goto dropfrag; 1109 if (ecn0 != IPTOS_ECN_CE) 1110 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 1111 } 1112 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 1113 goto dropfrag; 1114 1115 /* 1116 * Find a segment which begins after this one does. 1117 */ 1118 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1119 if (GETIP(q)->ip_off > ip->ip_off) 1120 break; 1121 1122 /* 1123 * If there is a preceding segment, it may provide some of 1124 * our data already. If so, drop the data from the incoming 1125 * segment. If it provides all of our data, drop us, otherwise 1126 * stick new segment in the proper place. 1127 * 1128 * If some of the data is dropped from the the preceding 1129 * segment, then it's checksum is invalidated. 1130 */ 1131 if (p) { 1132 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1133 if (i > 0) { 1134 if (i >= ip->ip_len) 1135 goto dropfrag; 1136 m_adj(m, i); 1137 m->m_pkthdr.csum_flags = 0; 1138 ip->ip_off += i; 1139 ip->ip_len -= i; 1140 } 1141 m->m_nextpkt = p->m_nextpkt; 1142 p->m_nextpkt = m; 1143 } else { 1144 m->m_nextpkt = fp->ipq_frags; 1145 fp->ipq_frags = m; 1146 } 1147 1148 /* 1149 * While we overlap succeeding segments trim them or, 1150 * if they are completely covered, dequeue them. 1151 */ 1152 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1153 q = nq) { 1154 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1155 if (i < GETIP(q)->ip_len) { 1156 GETIP(q)->ip_len -= i; 1157 GETIP(q)->ip_off += i; 1158 m_adj(q, i); 1159 q->m_pkthdr.csum_flags = 0; 1160 break; 1161 } 1162 nq = q->m_nextpkt; 1163 m->m_nextpkt = nq; 1164 ipstat.ips_fragdropped++; 1165 fp->ipq_nfrags--; 1166 m_freem(q); 1167 } 1168 1169 inserted: 1170 1171 #ifdef IPDIVERT 1172 /* 1173 * Transfer firewall instructions to the fragment structure. 1174 * Only trust info in the fragment at offset 0. 1175 */ 1176 if (ip->ip_off == 0) { 1177 fp->ipq_div_info = *divinfo; 1178 fp->ipq_div_cookie = *divert_rule; 1179 } 1180 *divinfo = 0; 1181 *divert_rule = 0; 1182 #endif 1183 1184 /* 1185 * Check for complete reassembly and perform frag per packet 1186 * limiting. 1187 * 1188 * Frag limiting is performed here so that the nth frag has 1189 * a chance to complete the packet before we drop the packet. 1190 * As a result, n+1 frags are actually allowed per packet, but 1191 * only n will ever be stored. (n = maxfragsperpacket.) 1192 * 1193 */ 1194 next = 0; 1195 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1196 if (GETIP(q)->ip_off != next) { 1197 if (fp->ipq_nfrags > maxfragsperpacket) { 1198 ipstat.ips_fragdropped += fp->ipq_nfrags; 1199 ip_freef(head, fp); 1200 } 1201 return (0); 1202 } 1203 next += GETIP(q)->ip_len; 1204 } 1205 /* Make sure the last packet didn't have the IP_MF flag */ 1206 if (p->m_flags & M_FRAG) { 1207 if (fp->ipq_nfrags > maxfragsperpacket) { 1208 ipstat.ips_fragdropped += fp->ipq_nfrags; 1209 ip_freef(head, fp); 1210 } 1211 return (0); 1212 } 1213 1214 /* 1215 * Reassembly is complete. Make sure the packet is a sane size. 1216 */ 1217 q = fp->ipq_frags; 1218 ip = GETIP(q); 1219 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1220 ipstat.ips_toolong++; 1221 ipstat.ips_fragdropped += fp->ipq_nfrags; 1222 ip_freef(head, fp); 1223 return (0); 1224 } 1225 1226 /* 1227 * Concatenate fragments. 1228 */ 1229 m = q; 1230 t = m->m_next; 1231 m->m_next = 0; 1232 m_cat(m, t); 1233 nq = q->m_nextpkt; 1234 q->m_nextpkt = 0; 1235 for (q = nq; q != NULL; q = nq) { 1236 nq = q->m_nextpkt; 1237 q->m_nextpkt = NULL; 1238 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1239 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1240 m_cat(m, q); 1241 } 1242 #ifdef MAC 1243 mac_create_datagram_from_ipq(fp, m); 1244 mac_destroy_ipq(fp); 1245 #endif 1246 1247 #ifdef IPDIVERT 1248 /* 1249 * Extract firewall instructions from the fragment structure. 1250 */ 1251 *divinfo = fp->ipq_div_info; 1252 *divert_rule = fp->ipq_div_cookie; 1253 #endif 1254 1255 /* 1256 * Create header for new ip packet by 1257 * modifying header of first packet; 1258 * dequeue and discard fragment reassembly header. 1259 * Make header visible. 1260 */ 1261 ip->ip_len = next; 1262 ip->ip_src = fp->ipq_src; 1263 ip->ip_dst = fp->ipq_dst; 1264 TAILQ_REMOVE(head, fp, ipq_list); 1265 nipq--; 1266 (void) m_free(dtom(fp)); 1267 m->m_len += (ip->ip_hl << 2); 1268 m->m_data -= (ip->ip_hl << 2); 1269 /* some debugging cruft by sklower, below, will go away soon */ 1270 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1271 m_fixhdr(m); 1272 return (m); 1273 1274 dropfrag: 1275 #ifdef IPDIVERT 1276 *divinfo = 0; 1277 *divert_rule = 0; 1278 #endif 1279 ipstat.ips_fragdropped++; 1280 if (fp != NULL) 1281 fp->ipq_nfrags--; 1282 m_freem(m); 1283 return (0); 1284 1285 #undef GETIP 1286 } 1287 1288 /* 1289 * Free a fragment reassembly header and all 1290 * associated datagrams. 1291 */ 1292 static void 1293 ip_freef(fhp, fp) 1294 struct ipqhead *fhp; 1295 struct ipq *fp; 1296 { 1297 register struct mbuf *q; 1298 1299 IPQ_LOCK_ASSERT(); 1300 1301 while (fp->ipq_frags) { 1302 q = fp->ipq_frags; 1303 fp->ipq_frags = q->m_nextpkt; 1304 m_freem(q); 1305 } 1306 TAILQ_REMOVE(fhp, fp, ipq_list); 1307 (void) m_free(dtom(fp)); 1308 nipq--; 1309 } 1310 1311 /* 1312 * IP timer processing; 1313 * if a timer expires on a reassembly 1314 * queue, discard it. 1315 */ 1316 void 1317 ip_slowtimo() 1318 { 1319 register struct ipq *fp; 1320 int s = splnet(); 1321 int i; 1322 1323 IPQ_LOCK(); 1324 for (i = 0; i < IPREASS_NHASH; i++) { 1325 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1326 struct ipq *fpp; 1327 1328 fpp = fp; 1329 fp = TAILQ_NEXT(fp, ipq_list); 1330 if(--fpp->ipq_ttl == 0) { 1331 ipstat.ips_fragtimeout += fpp->ipq_nfrags; 1332 ip_freef(&ipq[i], fpp); 1333 } 1334 } 1335 } 1336 /* 1337 * If we are over the maximum number of fragments 1338 * (due to the limit being lowered), drain off 1339 * enough to get down to the new limit. 1340 */ 1341 if (maxnipq >= 0 && nipq > maxnipq) { 1342 for (i = 0; i < IPREASS_NHASH; i++) { 1343 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) { 1344 ipstat.ips_fragdropped += 1345 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1346 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1347 } 1348 } 1349 } 1350 IPQ_UNLOCK(); 1351 ipflow_slowtimo(); 1352 splx(s); 1353 } 1354 1355 /* 1356 * Drain off all datagram fragments. 1357 */ 1358 void 1359 ip_drain() 1360 { 1361 int i; 1362 1363 IPQ_LOCK(); 1364 for (i = 0; i < IPREASS_NHASH; i++) { 1365 while(!TAILQ_EMPTY(&ipq[i])) { 1366 ipstat.ips_fragdropped += 1367 TAILQ_FIRST(&ipq[i])->ipq_nfrags; 1368 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1369 } 1370 } 1371 IPQ_UNLOCK(); 1372 in_rtqdrain(); 1373 } 1374 1375 /* 1376 * Do option processing on a datagram, 1377 * possibly discarding it if bad options are encountered, 1378 * or forwarding it if source-routed. 1379 * The pass argument is used when operating in the IPSTEALTH 1380 * mode to tell what options to process: 1381 * [LS]SRR (pass 0) or the others (pass 1). 1382 * The reason for as many as two passes is that when doing IPSTEALTH, 1383 * non-routing options should be processed only if the packet is for us. 1384 * Returns 1 if packet has been forwarded/freed, 1385 * 0 if the packet should be processed further. 1386 */ 1387 static int 1388 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1389 { 1390 struct ip *ip = mtod(m, struct ip *); 1391 u_char *cp; 1392 struct in_ifaddr *ia; 1393 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1394 struct in_addr *sin, dst; 1395 n_time ntime; 1396 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 1397 struct route cro; /* copy of cached route */ 1398 1399 /* 1400 * Grab a copy of the route cache in case we need 1401 * to update to reflect source routing or the like. 1402 * Could optimize this to do it later... 1403 */ 1404 RTCACHE_GET(&cro); 1405 1406 dst = ip->ip_dst; 1407 cp = (u_char *)(ip + 1); 1408 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1409 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1410 opt = cp[IPOPT_OPTVAL]; 1411 if (opt == IPOPT_EOL) 1412 break; 1413 if (opt == IPOPT_NOP) 1414 optlen = 1; 1415 else { 1416 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1417 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1418 goto bad; 1419 } 1420 optlen = cp[IPOPT_OLEN]; 1421 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1422 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1423 goto bad; 1424 } 1425 } 1426 switch (opt) { 1427 1428 default: 1429 break; 1430 1431 /* 1432 * Source routing with record. 1433 * Find interface with current destination address. 1434 * If none on this machine then drop if strictly routed, 1435 * or do nothing if loosely routed. 1436 * Record interface address and bring up next address 1437 * component. If strictly routed make sure next 1438 * address is on directly accessible net. 1439 */ 1440 case IPOPT_LSRR: 1441 case IPOPT_SSRR: 1442 #ifdef IPSTEALTH 1443 if (ipstealth && pass > 0) 1444 break; 1445 #endif 1446 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1447 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1448 goto bad; 1449 } 1450 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1451 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1452 goto bad; 1453 } 1454 ipaddr.sin_addr = ip->ip_dst; 1455 ia = (struct in_ifaddr *) 1456 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1457 if (ia == 0) { 1458 if (opt == IPOPT_SSRR) { 1459 type = ICMP_UNREACH; 1460 code = ICMP_UNREACH_SRCFAIL; 1461 goto bad; 1462 } 1463 if (!ip_dosourceroute) 1464 goto nosourcerouting; 1465 /* 1466 * Loose routing, and not at next destination 1467 * yet; nothing to do except forward. 1468 */ 1469 break; 1470 } 1471 off--; /* 0 origin */ 1472 if (off > optlen - (int)sizeof(struct in_addr)) { 1473 /* 1474 * End of source route. Should be for us. 1475 */ 1476 if (!ip_acceptsourceroute) 1477 goto nosourcerouting; 1478 save_rte(cp, ip->ip_src); 1479 break; 1480 } 1481 #ifdef IPSTEALTH 1482 if (ipstealth) 1483 goto dropit; 1484 #endif 1485 if (!ip_dosourceroute) { 1486 if (ipforwarding) { 1487 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1488 /* 1489 * Acting as a router, so generate ICMP 1490 */ 1491 nosourcerouting: 1492 strcpy(buf, inet_ntoa(ip->ip_dst)); 1493 log(LOG_WARNING, 1494 "attempted source route from %s to %s\n", 1495 inet_ntoa(ip->ip_src), buf); 1496 type = ICMP_UNREACH; 1497 code = ICMP_UNREACH_SRCFAIL; 1498 goto bad; 1499 } else { 1500 /* 1501 * Not acting as a router, so silently drop. 1502 */ 1503 #ifdef IPSTEALTH 1504 dropit: 1505 #endif 1506 ipstat.ips_cantforward++; 1507 m_freem(m); 1508 return (1); 1509 } 1510 } 1511 1512 /* 1513 * locate outgoing interface 1514 */ 1515 (void)memcpy(&ipaddr.sin_addr, cp + off, 1516 sizeof(ipaddr.sin_addr)); 1517 1518 if (opt == IPOPT_SSRR) { 1519 #define INA struct in_ifaddr * 1520 #define SA struct sockaddr * 1521 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1522 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1523 } else 1524 ia = ip_rtaddr(ipaddr.sin_addr, &cro); 1525 if (ia == 0) { 1526 type = ICMP_UNREACH; 1527 code = ICMP_UNREACH_SRCFAIL; 1528 goto bad; 1529 } 1530 ip->ip_dst = ipaddr.sin_addr; 1531 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1532 sizeof(struct in_addr)); 1533 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1534 /* 1535 * Let ip_intr's mcast routing check handle mcast pkts 1536 */ 1537 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1538 break; 1539 1540 case IPOPT_RR: 1541 #ifdef IPSTEALTH 1542 if (ipstealth && pass == 0) 1543 break; 1544 #endif 1545 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1546 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1547 goto bad; 1548 } 1549 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1550 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1551 goto bad; 1552 } 1553 /* 1554 * If no space remains, ignore. 1555 */ 1556 off--; /* 0 origin */ 1557 if (off > optlen - (int)sizeof(struct in_addr)) 1558 break; 1559 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1560 sizeof(ipaddr.sin_addr)); 1561 /* 1562 * locate outgoing interface; if we're the destination, 1563 * use the incoming interface (should be same). 1564 */ 1565 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1566 (ia = ip_rtaddr(ipaddr.sin_addr, &cro)) == 0) { 1567 type = ICMP_UNREACH; 1568 code = ICMP_UNREACH_HOST; 1569 goto bad; 1570 } 1571 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1572 sizeof(struct in_addr)); 1573 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1574 break; 1575 1576 case IPOPT_TS: 1577 #ifdef IPSTEALTH 1578 if (ipstealth && pass == 0) 1579 break; 1580 #endif 1581 code = cp - (u_char *)ip; 1582 if (optlen < 4 || optlen > 40) { 1583 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1584 goto bad; 1585 } 1586 if ((off = cp[IPOPT_OFFSET]) < 5) { 1587 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1588 goto bad; 1589 } 1590 if (off > optlen - (int)sizeof(int32_t)) { 1591 cp[IPOPT_OFFSET + 1] += (1 << 4); 1592 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1593 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1594 goto bad; 1595 } 1596 break; 1597 } 1598 off--; /* 0 origin */ 1599 sin = (struct in_addr *)(cp + off); 1600 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1601 1602 case IPOPT_TS_TSONLY: 1603 break; 1604 1605 case IPOPT_TS_TSANDADDR: 1606 if (off + sizeof(n_time) + 1607 sizeof(struct in_addr) > optlen) { 1608 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1609 goto bad; 1610 } 1611 ipaddr.sin_addr = dst; 1612 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1613 m->m_pkthdr.rcvif); 1614 if (ia == 0) 1615 continue; 1616 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1617 sizeof(struct in_addr)); 1618 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1619 off += sizeof(struct in_addr); 1620 break; 1621 1622 case IPOPT_TS_PRESPEC: 1623 if (off + sizeof(n_time) + 1624 sizeof(struct in_addr) > optlen) { 1625 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1626 goto bad; 1627 } 1628 (void)memcpy(&ipaddr.sin_addr, sin, 1629 sizeof(struct in_addr)); 1630 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1631 continue; 1632 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1633 off += sizeof(struct in_addr); 1634 break; 1635 1636 default: 1637 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1638 goto bad; 1639 } 1640 ntime = iptime(); 1641 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 1642 cp[IPOPT_OFFSET] += sizeof(n_time); 1643 } 1644 } 1645 if (forward && ipforwarding) { 1646 ip_forward(m, &cro, 1, next_hop); 1647 return (1); 1648 } 1649 return (0); 1650 bad: 1651 icmp_error(m, type, code, 0, 0); 1652 ipstat.ips_badoptions++; 1653 return (1); 1654 } 1655 1656 /* 1657 * Given address of next destination (final or next hop), 1658 * return internet address info of interface to be used to get there. 1659 */ 1660 struct in_ifaddr * 1661 ip_rtaddr(dst, rt) 1662 struct in_addr dst; 1663 struct route *rt; 1664 { 1665 register struct sockaddr_in *sin; 1666 1667 sin = (struct sockaddr_in *)&rt->ro_dst; 1668 1669 if (rt->ro_rt == 0 || 1670 !(rt->ro_rt->rt_flags & RTF_UP) || 1671 dst.s_addr != sin->sin_addr.s_addr) { 1672 if (rt->ro_rt) { 1673 RTFREE(rt->ro_rt); 1674 rt->ro_rt = 0; 1675 } 1676 sin->sin_family = AF_INET; 1677 sin->sin_len = sizeof(*sin); 1678 sin->sin_addr = dst; 1679 1680 rtalloc_ign(rt, RTF_PRCLONING); 1681 } 1682 if (rt->ro_rt == 0) 1683 return ((struct in_ifaddr *)0); 1684 return (ifatoia(rt->ro_rt->rt_ifa)); 1685 } 1686 1687 /* 1688 * Save incoming source route for use in replies, 1689 * to be picked up later by ip_srcroute if the receiver is interested. 1690 */ 1691 static void 1692 save_rte(option, dst) 1693 u_char *option; 1694 struct in_addr dst; 1695 { 1696 unsigned olen; 1697 1698 olen = option[IPOPT_OLEN]; 1699 #ifdef DIAGNOSTIC 1700 if (ipprintfs) 1701 printf("save_rte: olen %d\n", olen); 1702 #endif 1703 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1704 return; 1705 bcopy(option, ip_srcrt.srcopt, olen); 1706 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1707 ip_srcrt.dst = dst; 1708 } 1709 1710 /* 1711 * Retrieve incoming source route for use in replies, 1712 * in the same form used by setsockopt. 1713 * The first hop is placed before the options, will be removed later. 1714 */ 1715 struct mbuf * 1716 ip_srcroute() 1717 { 1718 register struct in_addr *p, *q; 1719 register struct mbuf *m; 1720 1721 if (ip_nhops == 0) 1722 return ((struct mbuf *)0); 1723 m = m_get(M_DONTWAIT, MT_HEADER); 1724 if (m == 0) 1725 return ((struct mbuf *)0); 1726 1727 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1728 1729 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1730 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1731 OPTSIZ; 1732 #ifdef DIAGNOSTIC 1733 if (ipprintfs) 1734 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1735 #endif 1736 1737 /* 1738 * First save first hop for return route 1739 */ 1740 p = &ip_srcrt.route[ip_nhops - 1]; 1741 *(mtod(m, struct in_addr *)) = *p--; 1742 #ifdef DIAGNOSTIC 1743 if (ipprintfs) 1744 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1745 #endif 1746 1747 /* 1748 * Copy option fields and padding (nop) to mbuf. 1749 */ 1750 ip_srcrt.nop = IPOPT_NOP; 1751 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1752 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1753 &ip_srcrt.nop, OPTSIZ); 1754 q = (struct in_addr *)(mtod(m, caddr_t) + 1755 sizeof(struct in_addr) + OPTSIZ); 1756 #undef OPTSIZ 1757 /* 1758 * Record return path as an IP source route, 1759 * reversing the path (pointers are now aligned). 1760 */ 1761 while (p >= ip_srcrt.route) { 1762 #ifdef DIAGNOSTIC 1763 if (ipprintfs) 1764 printf(" %lx", (u_long)ntohl(q->s_addr)); 1765 #endif 1766 *q++ = *p--; 1767 } 1768 /* 1769 * Last hop goes to final destination. 1770 */ 1771 *q = ip_srcrt.dst; 1772 #ifdef DIAGNOSTIC 1773 if (ipprintfs) 1774 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1775 #endif 1776 return (m); 1777 } 1778 1779 /* 1780 * Strip out IP options, at higher 1781 * level protocol in the kernel. 1782 * Second argument is buffer to which options 1783 * will be moved, and return value is their length. 1784 * XXX should be deleted; last arg currently ignored. 1785 */ 1786 void 1787 ip_stripoptions(m, mopt) 1788 register struct mbuf *m; 1789 struct mbuf *mopt; 1790 { 1791 register int i; 1792 struct ip *ip = mtod(m, struct ip *); 1793 register caddr_t opts; 1794 int olen; 1795 1796 olen = (ip->ip_hl << 2) - sizeof (struct ip); 1797 opts = (caddr_t)(ip + 1); 1798 i = m->m_len - (sizeof (struct ip) + olen); 1799 bcopy(opts + olen, opts, (unsigned)i); 1800 m->m_len -= olen; 1801 if (m->m_flags & M_PKTHDR) 1802 m->m_pkthdr.len -= olen; 1803 ip->ip_v = IPVERSION; 1804 ip->ip_hl = sizeof(struct ip) >> 2; 1805 } 1806 1807 u_char inetctlerrmap[PRC_NCMDS] = { 1808 0, 0, 0, 0, 1809 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1810 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1811 EMSGSIZE, EHOSTUNREACH, 0, 0, 1812 0, 0, EHOSTUNREACH, 0, 1813 ENOPROTOOPT, ECONNREFUSED 1814 }; 1815 1816 /* 1817 * Forward a packet. If some error occurs return the sender 1818 * an icmp packet. Note we can't always generate a meaningful 1819 * icmp message because icmp doesn't have a large enough repertoire 1820 * of codes and types. 1821 * 1822 * If not forwarding, just drop the packet. This could be confusing 1823 * if ipforwarding was zero but some routing protocol was advancing 1824 * us as a gateway to somewhere. However, we must let the routing 1825 * protocol deal with that. 1826 * 1827 * The srcrt parameter indicates whether the packet is being forwarded 1828 * via a source route. 1829 */ 1830 static void 1831 ip_forward(struct mbuf *m, struct route *ro, 1832 int srcrt, struct sockaddr_in *next_hop) 1833 { 1834 struct ip *ip = mtod(m, struct ip *); 1835 struct rtentry *rt; 1836 int error, type = 0, code = 0; 1837 struct mbuf *mcopy; 1838 n_long dest; 1839 struct in_addr pkt_dst; 1840 struct ifnet *destifp; 1841 #if defined(IPSEC) || defined(FAST_IPSEC) 1842 struct ifnet dummyifp; 1843 #endif 1844 1845 dest = 0; 1846 /* 1847 * Cache the destination address of the packet; this may be 1848 * changed by use of 'ipfw fwd'. 1849 */ 1850 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 1851 1852 #ifdef DIAGNOSTIC 1853 if (ipprintfs) 1854 printf("forward: src %lx dst %lx ttl %x\n", 1855 (u_long)ip->ip_src.s_addr, (u_long)pkt_dst.s_addr, 1856 ip->ip_ttl); 1857 #endif 1858 1859 1860 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(pkt_dst) == 0) { 1861 ipstat.ips_cantforward++; 1862 m_freem(m); 1863 return; 1864 } 1865 #ifdef IPSTEALTH 1866 if (!ipstealth) { 1867 #endif 1868 if (ip->ip_ttl <= IPTTLDEC) { 1869 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1870 dest, 0); 1871 return; 1872 } 1873 #ifdef IPSTEALTH 1874 } 1875 #endif 1876 1877 if (ip_rtaddr(pkt_dst, ro) == 0) { 1878 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1879 return; 1880 } else 1881 rt = ro->ro_rt; 1882 1883 /* 1884 * Save the IP header and at most 8 bytes of the payload, 1885 * in case we need to generate an ICMP message to the src. 1886 * 1887 * XXX this can be optimized a lot by saving the data in a local 1888 * buffer on the stack (72 bytes at most), and only allocating the 1889 * mbuf if really necessary. The vast majority of the packets 1890 * are forwarded without having to send an ICMP back (either 1891 * because unnecessary, or because rate limited), so we are 1892 * really we are wasting a lot of work here. 1893 * 1894 * We don't use m_copy() because it might return a reference 1895 * to a shared cluster. Both this function and ip_output() 1896 * assume exclusive access to the IP header in `m', so any 1897 * data in a cluster may change before we reach icmp_error(). 1898 */ 1899 MGET(mcopy, M_DONTWAIT, m->m_type); 1900 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1901 /* 1902 * It's probably ok if the pkthdr dup fails (because 1903 * the deep copy of the tag chain failed), but for now 1904 * be conservative and just discard the copy since 1905 * code below may some day want the tags. 1906 */ 1907 m_free(mcopy); 1908 mcopy = NULL; 1909 } 1910 if (mcopy != NULL) { 1911 mcopy->m_len = imin((ip->ip_hl << 2) + 8, 1912 (int)ip->ip_len); 1913 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1914 } 1915 1916 #ifdef IPSTEALTH 1917 if (!ipstealth) { 1918 #endif 1919 ip->ip_ttl -= IPTTLDEC; 1920 #ifdef IPSTEALTH 1921 } 1922 #endif 1923 1924 /* 1925 * If forwarding packet using same interface that it came in on, 1926 * perhaps should send a redirect to sender to shortcut a hop. 1927 * Only send redirect if source is sending directly to us, 1928 * and if packet was not source routed (or has any options). 1929 * Also, don't send redirect if forwarding using a default route 1930 * or a route modified by a redirect. 1931 */ 1932 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1933 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1934 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1935 ipsendredirects && !srcrt && !next_hop) { 1936 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1937 u_long src = ntohl(ip->ip_src.s_addr); 1938 1939 if (RTA(rt) && 1940 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1941 if (rt->rt_flags & RTF_GATEWAY) 1942 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1943 else 1944 dest = pkt_dst.s_addr; 1945 /* Router requirements says to only send host redirects */ 1946 type = ICMP_REDIRECT; 1947 code = ICMP_REDIRECT_HOST; 1948 #ifdef DIAGNOSTIC 1949 if (ipprintfs) 1950 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1951 #endif 1952 } 1953 } 1954 1955 { 1956 struct m_hdr tag; 1957 1958 if (next_hop) { 1959 /* Pass IPFORWARD info if available */ 1960 1961 tag.mh_type = MT_TAG; 1962 tag.mh_flags = PACKET_TAG_IPFORWARD; 1963 tag.mh_data = (caddr_t)next_hop; 1964 tag.mh_next = m; 1965 m = (struct mbuf *)&tag; 1966 } 1967 error = ip_output(m, (struct mbuf *)0, ro, IP_FORWARDING, 0, NULL); 1968 } 1969 /* 1970 * Update the ip forwarding cache with the route we used. 1971 * We may want to do this more selectively; not sure. 1972 */ 1973 RTCACHE_UPDATE(ro); 1974 if (error) 1975 ipstat.ips_cantforward++; 1976 else { 1977 ipstat.ips_forward++; 1978 if (type) 1979 ipstat.ips_redirectsent++; 1980 else { 1981 if (mcopy) { 1982 ipflow_create(ro, mcopy); 1983 m_freem(mcopy); 1984 } 1985 return; 1986 } 1987 } 1988 if (mcopy == NULL) 1989 return; 1990 destifp = NULL; 1991 1992 switch (error) { 1993 1994 case 0: /* forwarded, but need redirect */ 1995 /* type, code set above */ 1996 break; 1997 1998 case ENETUNREACH: /* shouldn't happen, checked above */ 1999 case EHOSTUNREACH: 2000 case ENETDOWN: 2001 case EHOSTDOWN: 2002 default: 2003 type = ICMP_UNREACH; 2004 code = ICMP_UNREACH_HOST; 2005 break; 2006 2007 case EMSGSIZE: 2008 type = ICMP_UNREACH; 2009 code = ICMP_UNREACH_NEEDFRAG; 2010 #ifdef IPSEC 2011 /* 2012 * If the packet is routed over IPsec tunnel, tell the 2013 * originator the tunnel MTU. 2014 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2015 * XXX quickhack!!! 2016 */ 2017 if (ro->ro_rt) { 2018 struct secpolicy *sp = NULL; 2019 int ipsecerror; 2020 int ipsechdr; 2021 2022 sp = ipsec4_getpolicybyaddr(mcopy, 2023 IPSEC_DIR_OUTBOUND, 2024 IP_FORWARDING, 2025 &ipsecerror); 2026 2027 if (sp == NULL) 2028 destifp = ro->ro_rt->rt_ifp; 2029 else { 2030 /* count IPsec header size */ 2031 ipsechdr = ipsec4_hdrsiz(mcopy, 2032 IPSEC_DIR_OUTBOUND, 2033 NULL); 2034 2035 /* 2036 * find the correct route for outer IPv4 2037 * header, compute tunnel MTU. 2038 * 2039 * XXX BUG ALERT 2040 * The "dummyifp" code relies upon the fact 2041 * that icmp_error() touches only ifp->if_mtu. 2042 */ 2043 /*XXX*/ 2044 destifp = NULL; 2045 if (sp->req != NULL 2046 && sp->req->sav != NULL 2047 && sp->req->sav->sah != NULL) { 2048 struct route *saro; 2049 saro = &sp->req->sav->sah->sa_route; 2050 if (saro->ro_rt && saro->ro_rt->rt_ifp) { 2051 dummyifp.if_mtu = 2052 saro->ro_rt->rt_ifp->if_mtu; 2053 dummyifp.if_mtu -= ipsechdr; 2054 destifp = &dummyifp; 2055 } 2056 } 2057 2058 key_freesp(sp); 2059 } 2060 } 2061 #elif FAST_IPSEC 2062 /* 2063 * If the packet is routed over IPsec tunnel, tell the 2064 * originator the tunnel MTU. 2065 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 2066 * XXX quickhack!!! 2067 */ 2068 if (ro->ro_rt) { 2069 struct secpolicy *sp = NULL; 2070 int ipsecerror; 2071 int ipsechdr; 2072 2073 sp = ipsec_getpolicybyaddr(mcopy, 2074 IPSEC_DIR_OUTBOUND, 2075 IP_FORWARDING, 2076 &ipsecerror); 2077 2078 if (sp == NULL) 2079 destifp = ro->ro_rt->rt_ifp; 2080 else { 2081 /* count IPsec header size */ 2082 ipsechdr = ipsec4_hdrsiz(mcopy, 2083 IPSEC_DIR_OUTBOUND, 2084 NULL); 2085 2086 /* 2087 * find the correct route for outer IPv4 2088 * header, compute tunnel MTU. 2089 * 2090 * XXX BUG ALERT 2091 * The "dummyifp" code relies upon the fact 2092 * that icmp_error() touches only ifp->if_mtu. 2093 */ 2094 /*XXX*/ 2095 destifp = NULL; 2096 if (sp->req != NULL 2097 && sp->req->sav != NULL 2098 && sp->req->sav->sah != NULL) { 2099 struct route *saro; 2100 saro = &sp->req->sav->sah->sa_route; 2101 if (saro->ro_rt && saro->ro_rt->rt_ifp) { 2102 dummyifp.if_mtu = 2103 saro->ro_rt->rt_ifp->if_mtu; 2104 dummyifp.if_mtu -= ipsechdr; 2105 destifp = &dummyifp; 2106 } 2107 } 2108 2109 KEY_FREESP(&sp); 2110 } 2111 } 2112 #else /* !IPSEC && !FAST_IPSEC */ 2113 if (ro->ro_rt) 2114 destifp = ro->ro_rt->rt_ifp; 2115 #endif /*IPSEC*/ 2116 ipstat.ips_cantfrag++; 2117 break; 2118 2119 case ENOBUFS: 2120 /* 2121 * A router should not generate ICMP_SOURCEQUENCH as 2122 * required in RFC1812 Requirements for IP Version 4 Routers. 2123 * Source quench could be a big problem under DoS attacks, 2124 * or if the underlying interface is rate-limited. 2125 * Those who need source quench packets may re-enable them 2126 * via the net.inet.ip.sendsourcequench sysctl. 2127 */ 2128 if (ip_sendsourcequench == 0) { 2129 m_freem(mcopy); 2130 return; 2131 } else { 2132 type = ICMP_SOURCEQUENCH; 2133 code = 0; 2134 } 2135 break; 2136 2137 case EACCES: /* ipfw denied packet */ 2138 m_freem(mcopy); 2139 return; 2140 } 2141 icmp_error(mcopy, type, code, dest, destifp); 2142 } 2143 2144 void 2145 ip_savecontrol(inp, mp, ip, m) 2146 register struct inpcb *inp; 2147 register struct mbuf **mp; 2148 register struct ip *ip; 2149 register struct mbuf *m; 2150 { 2151 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2152 struct timeval tv; 2153 2154 microtime(&tv); 2155 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2156 SCM_TIMESTAMP, SOL_SOCKET); 2157 if (*mp) 2158 mp = &(*mp)->m_next; 2159 } 2160 if (inp->inp_flags & INP_RECVDSTADDR) { 2161 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2162 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2163 if (*mp) 2164 mp = &(*mp)->m_next; 2165 } 2166 if (inp->inp_flags & INP_RECVTTL) { 2167 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2168 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2169 if (*mp) 2170 mp = &(*mp)->m_next; 2171 } 2172 #ifdef notyet 2173 /* XXX 2174 * Moving these out of udp_input() made them even more broken 2175 * than they already were. 2176 */ 2177 /* options were tossed already */ 2178 if (inp->inp_flags & INP_RECVOPTS) { 2179 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2180 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2181 if (*mp) 2182 mp = &(*mp)->m_next; 2183 } 2184 /* ip_srcroute doesn't do what we want here, need to fix */ 2185 if (inp->inp_flags & INP_RECVRETOPTS) { 2186 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 2187 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2188 if (*mp) 2189 mp = &(*mp)->m_next; 2190 } 2191 #endif 2192 if (inp->inp_flags & INP_RECVIF) { 2193 struct ifnet *ifp; 2194 struct sdlbuf { 2195 struct sockaddr_dl sdl; 2196 u_char pad[32]; 2197 } sdlbuf; 2198 struct sockaddr_dl *sdp; 2199 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2200 2201 if (((ifp = m->m_pkthdr.rcvif)) 2202 && ( ifp->if_index && (ifp->if_index <= if_index))) { 2203 sdp = (struct sockaddr_dl *) 2204 (ifaddr_byindex(ifp->if_index)->ifa_addr); 2205 /* 2206 * Change our mind and don't try copy. 2207 */ 2208 if ((sdp->sdl_family != AF_LINK) 2209 || (sdp->sdl_len > sizeof(sdlbuf))) { 2210 goto makedummy; 2211 } 2212 bcopy(sdp, sdl2, sdp->sdl_len); 2213 } else { 2214 makedummy: 2215 sdl2->sdl_len 2216 = offsetof(struct sockaddr_dl, sdl_data[0]); 2217 sdl2->sdl_family = AF_LINK; 2218 sdl2->sdl_index = 0; 2219 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2220 } 2221 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2222 IP_RECVIF, IPPROTO_IP); 2223 if (*mp) 2224 mp = &(*mp)->m_next; 2225 } 2226 } 2227 2228 /* 2229 * XXX these routines are called from the upper part of the kernel. 2230 * They need to be locked when we remove Giant. 2231 * 2232 * They could also be moved to ip_mroute.c, since all the RSVP 2233 * handling is done there already. 2234 */ 2235 static int ip_rsvp_on; 2236 struct socket *ip_rsvpd; 2237 int 2238 ip_rsvp_init(struct socket *so) 2239 { 2240 if (so->so_type != SOCK_RAW || 2241 so->so_proto->pr_protocol != IPPROTO_RSVP) 2242 return EOPNOTSUPP; 2243 2244 if (ip_rsvpd != NULL) 2245 return EADDRINUSE; 2246 2247 ip_rsvpd = so; 2248 /* 2249 * This may seem silly, but we need to be sure we don't over-increment 2250 * the RSVP counter, in case something slips up. 2251 */ 2252 if (!ip_rsvp_on) { 2253 ip_rsvp_on = 1; 2254 rsvp_on++; 2255 } 2256 2257 return 0; 2258 } 2259 2260 int 2261 ip_rsvp_done(void) 2262 { 2263 ip_rsvpd = NULL; 2264 /* 2265 * This may seem silly, but we need to be sure we don't over-decrement 2266 * the RSVP counter, in case something slips up. 2267 */ 2268 if (ip_rsvp_on) { 2269 ip_rsvp_on = 0; 2270 rsvp_on--; 2271 } 2272 return 0; 2273 } 2274 2275 void 2276 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 2277 { 2278 if (rsvp_input_p) { /* call the real one if loaded */ 2279 rsvp_input_p(m, off); 2280 return; 2281 } 2282 2283 /* Can still get packets with rsvp_on = 0 if there is a local member 2284 * of the group to which the RSVP packet is addressed. But in this 2285 * case we want to throw the packet away. 2286 */ 2287 2288 if (!rsvp_on) { 2289 m_freem(m); 2290 return; 2291 } 2292 2293 if (ip_rsvpd != NULL) { 2294 rip_input(m, off); 2295 return; 2296 } 2297 /* Drop the packet */ 2298 m_freem(m); 2299 } 2300