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 #define _IP_VHL 38 39 #include "opt_bootp.h" 40 #include "opt_ipfw.h" 41 #include "opt_ipdn.h" 42 #include "opt_ipdivert.h" 43 #include "opt_ipfilter.h" 44 #include "opt_ipstealth.h" 45 #include "opt_ipsec.h" 46 #include "opt_pfil_hooks.h" 47 #include "opt_random_ip_id.h" 48 49 #include <sys/param.h> 50 #include <sys/systm.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_var.h> 64 #include <net/if_dl.h> 65 #include <net/route.h> 66 #include <net/netisr.h> 67 #include <net/intrq.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 82 #ifdef IPSEC 83 #include <netinet6/ipsec.h> 84 #include <netkey/key.h> 85 #endif 86 87 #include "faith.h" 88 #if defined(NFAITH) && NFAITH > 0 89 #include <net/if_types.h> 90 #endif 91 92 #ifdef DUMMYNET 93 #include <netinet/ip_dummynet.h> 94 #endif 95 96 int rsvp_on = 0; 97 static int ip_rsvp_on; 98 struct socket *ip_rsvpd; 99 100 int ipforwarding = 0; 101 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 102 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 103 104 static int ipsendredirects = 1; /* XXX */ 105 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 106 &ipsendredirects, 0, "Enable sending IP redirects"); 107 108 int ip_defttl = IPDEFTTL; 109 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 110 &ip_defttl, 0, "Maximum TTL on IP packets"); 111 112 static int ip_dosourceroute = 0; 113 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 114 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 115 116 static int ip_acceptsourceroute = 0; 117 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 118 CTLFLAG_RW, &ip_acceptsourceroute, 0, 119 "Enable accepting source routed IP packets"); 120 121 static int ip_keepfaith = 0; 122 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 123 &ip_keepfaith, 0, 124 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 125 126 static int ip_nfragpackets = 0; 127 static int ip_maxfragpackets; /* initialized in ip_init() */ 128 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 129 &ip_maxfragpackets, 0, 130 "Maximum number of IPv4 fragment reassembly queue entries"); 131 132 /* 133 * XXX - Setting ip_checkinterface mostly implements the receive side of 134 * the Strong ES model described in RFC 1122, but since the routing table 135 * and transmit implementation do not implement the Strong ES model, 136 * setting this to 1 results in an odd hybrid. 137 * 138 * XXX - ip_checkinterface currently must be disabled if you use ipnat 139 * to translate the destination address to another local interface. 140 * 141 * XXX - ip_checkinterface must be disabled if you add IP aliases 142 * to the loopback interface instead of the interface where the 143 * packets for those addresses are received. 144 */ 145 static int ip_checkinterface = 1; 146 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 147 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 148 149 #ifdef DIAGNOSTIC 150 static int ipprintfs = 0; 151 #endif 152 153 extern struct domain inetdomain; 154 extern struct protosw inetsw[]; 155 u_char ip_protox[IPPROTO_MAX]; 156 static int ipqmaxlen = IFQ_MAXLEN; 157 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 158 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 159 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 160 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 161 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 162 163 struct ipstat ipstat; 164 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 165 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 166 167 /* Packet reassembly stuff */ 168 #define IPREASS_NHASH_LOG2 6 169 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 170 #define IPREASS_HMASK (IPREASS_NHASH - 1) 171 #define IPREASS_HASH(x,y) \ 172 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 173 174 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; 175 static int nipq = 0; /* total # of reass queues */ 176 static int maxnipq; 177 const int ipintrq_present = 1; 178 179 #ifdef IPCTL_DEFMTU 180 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 181 &ip_mtu, 0, "Default MTU"); 182 #endif 183 184 #ifdef IPSTEALTH 185 static int ipstealth = 0; 186 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 187 &ipstealth, 0, ""); 188 #endif 189 190 191 /* Firewall hooks */ 192 ip_fw_chk_t *ip_fw_chk_ptr; 193 ip_fw_ctl_t *ip_fw_ctl_ptr; 194 int fw_enable = 1 ; 195 196 #ifdef DUMMYNET 197 ip_dn_ctl_t *ip_dn_ctl_ptr; 198 #endif 199 200 201 /* 202 * We need to save the IP options in case a protocol wants to respond 203 * to an incoming packet over the same route if the packet got here 204 * using IP source routing. This allows connection establishment and 205 * maintenance when the remote end is on a network that is not known 206 * to us. 207 */ 208 static int ip_nhops = 0; 209 static struct ip_srcrt { 210 struct in_addr dst; /* final destination */ 211 char nop; /* one NOP to align */ 212 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 213 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 214 } ip_srcrt; 215 216 struct sockaddr_in *ip_fw_fwd_addr; 217 218 static void save_rte __P((u_char *, struct in_addr)); 219 static int ip_dooptions __P((struct mbuf *)); 220 static void ip_forward __P((struct mbuf *, int)); 221 static void ip_freef __P((struct ipqhead *, struct ipq *)); 222 #ifdef IPDIVERT 223 static struct mbuf *ip_reass __P((struct mbuf *, struct ipqhead *, struct ipq *, u_int32_t *, u_int16_t *)); 224 #else 225 static struct mbuf *ip_reass __P((struct mbuf *, struct ipqhead *, struct ipq *)); 226 #endif 227 static struct in_ifaddr *ip_rtaddr __P((struct in_addr)); 228 static void ipintr __P((void)); 229 230 /* 231 * IP initialization: fill in IP protocol switch table. 232 * All protocols not implemented in kernel go to raw IP protocol handler. 233 */ 234 void 235 ip_init() 236 { 237 register struct protosw *pr; 238 register int i; 239 240 TAILQ_INIT(&in_ifaddrhead); 241 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 242 if (pr == 0) 243 panic("ip_init"); 244 for (i = 0; i < IPPROTO_MAX; i++) 245 ip_protox[i] = pr - inetsw; 246 for (pr = inetdomain.dom_protosw; 247 pr < inetdomain.dom_protoswNPROTOSW; pr++) 248 if (pr->pr_domain->dom_family == PF_INET && 249 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 250 ip_protox[pr->pr_protocol] = pr - inetsw; 251 252 for (i = 0; i < IPREASS_NHASH; i++) 253 TAILQ_INIT(&ipq[i]); 254 255 maxnipq = nmbclusters / 4; 256 ip_maxfragpackets = nmbclusters / 4; 257 258 #ifndef RANDOM_IP_ID 259 ip_id = time_second & 0xffff; 260 #endif 261 ipintrq.ifq_maxlen = ipqmaxlen; 262 mtx_init(&ipintrq.ifq_mtx, "ip_inq", MTX_DEF); 263 264 register_netisr(NETISR_IP, ipintr); 265 } 266 267 static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 268 struct route ipforward_rt; 269 270 /* 271 * Ip input routine. Checksum and byte swap header. If fragmented 272 * try to reassemble. Process options. Pass to next level. 273 */ 274 void 275 ip_input(struct mbuf *m) 276 { 277 struct ip *ip; 278 struct ipq *fp; 279 struct in_ifaddr *ia = NULL; 280 int i, hlen, checkif; 281 u_short sum; 282 u_int16_t divert_cookie; /* firewall cookie */ 283 struct in_addr pkt_dst; 284 #ifdef IPDIVERT 285 u_int32_t divert_info = 0; /* packet divert/tee info */ 286 #endif 287 struct ip_fw_chain *rule = NULL; 288 #ifdef PFIL_HOOKS 289 struct packet_filter_hook *pfh; 290 struct mbuf *m0; 291 int rv; 292 #endif /* PFIL_HOOKS */ 293 294 #ifdef IPDIVERT 295 /* Get and reset firewall cookie */ 296 divert_cookie = ip_divert_cookie; 297 ip_divert_cookie = 0; 298 #else 299 divert_cookie = 0; 300 #endif 301 302 #if defined(IPFIREWALL) && defined(DUMMYNET) 303 /* 304 * dummynet packet are prepended a vestigial mbuf with 305 * m_type = MT_DUMMYNET and m_data pointing to the matching 306 * rule. 307 */ 308 if (m->m_type == MT_DUMMYNET) { 309 rule = (struct ip_fw_chain *)(m->m_data) ; 310 m = m->m_next ; 311 ip = mtod(m, struct ip *); 312 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 313 goto iphack ; 314 } else 315 rule = NULL ; 316 #endif 317 318 #ifdef DIAGNOSTIC 319 if (m == NULL || (m->m_flags & M_PKTHDR) == 0) 320 panic("ip_input no HDR"); 321 #endif 322 ipstat.ips_total++; 323 324 if (m->m_pkthdr.len < sizeof(struct ip)) 325 goto tooshort; 326 327 if (m->m_len < sizeof (struct ip) && 328 (m = m_pullup(m, sizeof (struct ip))) == 0) { 329 ipstat.ips_toosmall++; 330 return; 331 } 332 ip = mtod(m, struct ip *); 333 334 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 335 ipstat.ips_badvers++; 336 goto bad; 337 } 338 339 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 340 if (hlen < sizeof(struct ip)) { /* minimum header length */ 341 ipstat.ips_badhlen++; 342 goto bad; 343 } 344 if (hlen > m->m_len) { 345 if ((m = m_pullup(m, hlen)) == 0) { 346 ipstat.ips_badhlen++; 347 return; 348 } 349 ip = mtod(m, struct ip *); 350 } 351 352 /* 127/8 must not appear on wire - RFC1122 */ 353 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 354 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 355 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 356 ipstat.ips_badaddr++; 357 goto bad; 358 } 359 } 360 361 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 362 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 363 } else { 364 if (hlen == sizeof(struct ip)) { 365 sum = in_cksum_hdr(ip); 366 } else { 367 sum = in_cksum(m, hlen); 368 } 369 } 370 if (sum) { 371 ipstat.ips_badsum++; 372 goto bad; 373 } 374 375 /* 376 * Convert fields to host representation. 377 */ 378 NTOHS(ip->ip_len); 379 if (ip->ip_len < hlen) { 380 ipstat.ips_badlen++; 381 goto bad; 382 } 383 NTOHS(ip->ip_off); 384 385 /* 386 * Check that the amount of data in the buffers 387 * is as at least much as the IP header would have us expect. 388 * Trim mbufs if longer than we expect. 389 * Drop packet if shorter than we expect. 390 */ 391 if (m->m_pkthdr.len < ip->ip_len) { 392 tooshort: 393 ipstat.ips_tooshort++; 394 goto bad; 395 } 396 if (m->m_pkthdr.len > ip->ip_len) { 397 if (m->m_len == m->m_pkthdr.len) { 398 m->m_len = ip->ip_len; 399 m->m_pkthdr.len = ip->ip_len; 400 } else 401 m_adj(m, ip->ip_len - m->m_pkthdr.len); 402 } 403 404 #ifdef IPSEC 405 if (ipsec_gethist(m, NULL)) 406 goto pass; 407 #endif 408 409 /* 410 * IpHack's section. 411 * Right now when no processing on packet has done 412 * and it is still fresh out of network we do our black 413 * deals with it. 414 * - Firewall: deny/allow/divert 415 * - Xlate: translate packet's addr/port (NAT). 416 * - Pipe: pass pkt through dummynet. 417 * - Wrap: fake packet's addr/port <unimpl.> 418 * - Encapsulate: put it in another IP and send out. <unimp.> 419 */ 420 421 #if defined(IPFIREWALL) && defined(DUMMYNET) 422 iphack: 423 #endif 424 425 #ifdef PFIL_HOOKS 426 /* 427 * Run through list of hooks for input packets. If there are any 428 * filters which require that additional packets in the flow are 429 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 430 * Note that filters must _never_ set this flag, as another filter 431 * in the list may have previously cleared it. 432 */ 433 m0 = m; 434 pfh = pfil_hook_get(PFIL_IN, &inetsw[ip_protox[IPPROTO_IP]].pr_pfh); 435 for (; pfh; pfh = TAILQ_NEXT(pfh, pfil_link)) 436 if (pfh->pfil_func) { 437 rv = pfh->pfil_func(ip, hlen, 438 m->m_pkthdr.rcvif, 0, &m0); 439 if (rv) 440 return; 441 m = m0; 442 if (m == NULL) 443 return; 444 ip = mtod(m, struct ip *); 445 } 446 #endif /* PFIL_HOOKS */ 447 448 if (fw_enable && ip_fw_chk_ptr) { 449 #ifdef IPFIREWALL_FORWARD 450 /* 451 * If we've been forwarded from the output side, then 452 * skip the firewall a second time 453 */ 454 if (ip_fw_fwd_addr) 455 goto ours; 456 #endif /* IPFIREWALL_FORWARD */ 457 /* 458 * See the comment in ip_output for the return values 459 * produced by the firewall. 460 */ 461 i = (*ip_fw_chk_ptr)(&ip, 462 hlen, NULL, &divert_cookie, &m, &rule, &ip_fw_fwd_addr); 463 if (i & IP_FW_PORT_DENY_FLAG) { /* XXX new interface-denied */ 464 if (m) 465 m_freem(m); 466 return ; 467 } 468 if (m == NULL) { /* Packet discarded by firewall */ 469 static int __debug=10; 470 if (__debug >0) { 471 printf("firewall returns NULL, please update!\n"); 472 __debug-- ; 473 } 474 return; 475 } 476 if (i == 0 && ip_fw_fwd_addr == NULL) /* common case */ 477 goto pass; 478 #ifdef DUMMYNET 479 if ((i & IP_FW_PORT_DYNT_FLAG) != 0) { 480 /* Send packet to the appropriate pipe */ 481 dummynet_io(i&0xffff,DN_TO_IP_IN,m,NULL,NULL,0, rule, 482 0); 483 return; 484 } 485 #endif 486 #ifdef IPDIVERT 487 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 488 /* Divert or tee packet */ 489 divert_info = i; 490 goto ours; 491 } 492 #endif 493 #ifdef IPFIREWALL_FORWARD 494 if (i == 0 && ip_fw_fwd_addr != NULL) 495 goto pass; 496 #endif 497 /* 498 * if we get here, the packet must be dropped 499 */ 500 m_freem(m); 501 return; 502 } 503 pass: 504 505 /* 506 * Process options and, if not destined for us, 507 * ship it on. ip_dooptions returns 1 when an 508 * error was detected (causing an icmp message 509 * to be sent and the original packet to be freed). 510 */ 511 ip_nhops = 0; /* for source routed packets */ 512 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 513 #ifdef IPFIREWALL_FORWARD 514 ip_fw_fwd_addr = NULL; 515 #endif 516 return; 517 } 518 519 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 520 * matter if it is destined to another node, or whether it is 521 * a multicast one, RSVP wants it! and prevents it from being forwarded 522 * anywhere else. Also checks if the rsvp daemon is running before 523 * grabbing the packet. 524 */ 525 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 526 goto ours; 527 528 /* 529 * Check our list of addresses, to see if the packet is for us. 530 * If we don't have any addresses, assume any unicast packet 531 * we receive might be for us (and let the upper layers deal 532 * with it). 533 */ 534 if (TAILQ_EMPTY(&in_ifaddrhead) && 535 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 536 goto ours; 537 538 /* 539 * Cache the destination address of the packet; this may be 540 * changed by use of 'ipfw fwd'. 541 */ 542 pkt_dst = ip_fw_fwd_addr == NULL ? 543 ip->ip_dst : ip_fw_fwd_addr->sin_addr; 544 545 /* 546 * Enable a consistency check between the destination address 547 * and the arrival interface for a unicast packet (the RFC 1122 548 * strong ES model) if IP forwarding is disabled and the packet 549 * is not locally generated and the packet is not subject to 550 * 'ipfw fwd'. 551 * 552 * XXX - Checking also should be disabled if the destination 553 * address is ipnat'ed to a different interface. 554 * 555 * XXX - Checking is incompatible with IP aliases added 556 * to the loopback interface instead of the interface where 557 * the packets are received. 558 */ 559 checkif = ip_checkinterface && (ipforwarding == 0) && 560 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) && 561 (ip_fw_fwd_addr == NULL); 562 563 TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link) { 564 #define satosin(sa) ((struct sockaddr_in *)(sa)) 565 566 #ifdef BOOTP_COMPAT 567 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 568 goto ours; 569 #endif 570 /* 571 * If the address matches, verify that the packet 572 * arrived via the correct interface if checking is 573 * enabled. 574 */ 575 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 576 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 577 goto ours; 578 /* 579 * Only accept broadcast packets that arrive via the 580 * matching interface. Reception of forwarded directed 581 * broadcasts would be handled via ip_forward() and 582 * ether_output() with the loopback into the stack for 583 * SIMPLEX interfaces handled by ether_output(). 584 */ 585 if (ia->ia_ifp == m->m_pkthdr.rcvif && 586 ia->ia_ifp && ia->ia_ifp->if_flags & IFF_BROADCAST) { 587 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 588 pkt_dst.s_addr) 589 goto ours; 590 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 591 goto ours; 592 } 593 } 594 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 595 struct in_multi *inm; 596 if (ip_mrouter) { 597 /* 598 * If we are acting as a multicast router, all 599 * incoming multicast packets are passed to the 600 * kernel-level multicast forwarding function. 601 * The packet is returned (relatively) intact; if 602 * ip_mforward() returns a non-zero value, the packet 603 * must be discarded, else it may be accepted below. 604 */ 605 if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 606 ipstat.ips_cantforward++; 607 m_freem(m); 608 return; 609 } 610 611 /* 612 * The process-level routing demon needs to receive 613 * all multicast IGMP packets, whether or not this 614 * host belongs to their destination groups. 615 */ 616 if (ip->ip_p == IPPROTO_IGMP) 617 goto ours; 618 ipstat.ips_forward++; 619 } 620 /* 621 * See if we belong to the destination multicast group on the 622 * arrival interface. 623 */ 624 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 625 if (inm == NULL) { 626 ipstat.ips_notmember++; 627 m_freem(m); 628 return; 629 } 630 goto ours; 631 } 632 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 633 goto ours; 634 if (ip->ip_dst.s_addr == INADDR_ANY) 635 goto ours; 636 637 #if defined(NFAITH) && 0 < NFAITH 638 /* 639 * FAITH(Firewall Aided Internet Translator) 640 */ 641 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 642 if (ip_keepfaith) { 643 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 644 goto ours; 645 } 646 m_freem(m); 647 return; 648 } 649 #endif 650 /* 651 * Not for us; forward if possible and desirable. 652 */ 653 if (ipforwarding == 0) { 654 ipstat.ips_cantforward++; 655 m_freem(m); 656 } else 657 ip_forward(m, 0); 658 #ifdef IPFIREWALL_FORWARD 659 ip_fw_fwd_addr = NULL; 660 #endif 661 return; 662 663 ours: 664 /* Count the packet in the ip address stats */ 665 if (ia != NULL) { 666 ia->ia_ifa.if_ipackets++; 667 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 668 } 669 670 /* 671 * If offset or IP_MF are set, must reassemble. 672 * Otherwise, nothing need be done. 673 * (We could look in the reassembly queue to see 674 * if the packet was previously fragmented, 675 * but it's not worth the time; just let them time out.) 676 */ 677 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 678 679 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 680 /* 681 * Look for queue of fragments 682 * of this datagram. 683 */ 684 TAILQ_FOREACH(fp, &ipq[sum], ipq_list) 685 if (ip->ip_id == fp->ipq_id && 686 ip->ip_src.s_addr == fp->ipq_src.s_addr && 687 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 688 ip->ip_p == fp->ipq_p) 689 goto found; 690 691 fp = 0; 692 693 /* check if there's a place for the new queue */ 694 if (nipq > maxnipq) { 695 /* 696 * drop something from the tail of the current queue 697 * before proceeding further 698 */ 699 struct ipq *q = TAILQ_LAST(&ipq[sum], ipqhead); 700 if (q == NULL) { /* gak */ 701 for (i = 0; i < IPREASS_NHASH; i++) { 702 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead); 703 if (r) { 704 ip_freef(&ipq[i], r); 705 break; 706 } 707 } 708 } else 709 ip_freef(&ipq[sum], q); 710 } 711 found: 712 /* 713 * Adjust ip_len to not reflect header, 714 * convert offset of this to bytes. 715 */ 716 ip->ip_len -= hlen; 717 if (ip->ip_off & IP_MF) { 718 /* 719 * Make sure that fragments have a data length 720 * that's a non-zero multiple of 8 bytes. 721 */ 722 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 723 ipstat.ips_toosmall++; /* XXX */ 724 goto bad; 725 } 726 m->m_flags |= M_FRAG; 727 } 728 ip->ip_off <<= 3; 729 730 /* 731 * Attempt reassembly; if it succeeds, proceed. 732 */ 733 ipstat.ips_fragments++; 734 m->m_pkthdr.header = ip; 735 #ifdef IPDIVERT 736 m = ip_reass(m, 737 &ipq[sum], fp, &divert_info, &divert_cookie); 738 #else 739 m = ip_reass(m, &ipq[sum], fp); 740 #endif 741 if (m == 0) { 742 #ifdef IPFIREWALL_FORWARD 743 ip_fw_fwd_addr = NULL; 744 #endif 745 return; 746 } 747 ipstat.ips_reassembled++; 748 ip = mtod(m, struct ip *); 749 /* Get the header length of the reassembled packet */ 750 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 751 #ifdef IPDIVERT 752 /* Restore original checksum before diverting packet */ 753 if (divert_info != 0) { 754 ip->ip_len += hlen; 755 HTONS(ip->ip_len); 756 HTONS(ip->ip_off); 757 ip->ip_sum = 0; 758 if (hlen == sizeof(struct ip)) 759 ip->ip_sum = in_cksum_hdr(ip); 760 else 761 ip->ip_sum = in_cksum(m, hlen); 762 NTOHS(ip->ip_off); 763 NTOHS(ip->ip_len); 764 ip->ip_len -= hlen; 765 } 766 #endif 767 } else 768 ip->ip_len -= hlen; 769 770 #ifdef IPDIVERT 771 /* 772 * Divert or tee packet to the divert protocol if required. 773 * 774 * If divert_info is zero then cookie should be too, so we shouldn't 775 * need to clear them here. Assume divert_packet() does so also. 776 */ 777 if (divert_info != 0) { 778 struct mbuf *clone = NULL; 779 780 /* Clone packet if we're doing a 'tee' */ 781 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 782 clone = m_dup(m, M_DONTWAIT); 783 784 /* Restore packet header fields to original values */ 785 ip->ip_len += hlen; 786 HTONS(ip->ip_len); 787 HTONS(ip->ip_off); 788 789 /* Deliver packet to divert input routine */ 790 ip_divert_cookie = divert_cookie; 791 divert_packet(m, 1, divert_info & 0xffff); 792 ipstat.ips_delivered++; 793 794 /* If 'tee', continue with original packet */ 795 if (clone == NULL) 796 return; 797 m = clone; 798 ip = mtod(m, struct ip *); 799 } 800 #endif 801 802 #ifdef IPSEC 803 /* 804 * enforce IPsec policy checking if we are seeing last header. 805 * note that we do not visit this with protocols with pcb layer 806 * code - like udp/tcp/raw ip. 807 */ 808 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 && 809 ipsec4_in_reject(m, NULL)) { 810 ipsecstat.in_polvio++; 811 goto bad; 812 } 813 #endif 814 815 /* 816 * Switch out to protocol's input routine. 817 */ 818 ipstat.ips_delivered++; 819 { 820 int off = hlen; 821 822 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, off); 823 #ifdef IPFIREWALL_FORWARD 824 ip_fw_fwd_addr = NULL; /* tcp needed it */ 825 #endif 826 return; 827 } 828 bad: 829 #ifdef IPFIREWALL_FORWARD 830 ip_fw_fwd_addr = NULL; 831 #endif 832 m_freem(m); 833 } 834 835 /* 836 * IP software interrupt routine - to go away sometime soon 837 */ 838 static void 839 ipintr(void) 840 { 841 struct mbuf *m; 842 843 while (1) { 844 IF_DEQUEUE(&ipintrq, m); 845 if (m == 0) 846 return; 847 ip_input(m); 848 } 849 } 850 851 /* 852 * Take incoming datagram fragment and try to reassemble it into 853 * whole datagram. If a chain for reassembly of this datagram already 854 * exists, then it is given as fp; otherwise have to make a chain. 855 * 856 * When IPDIVERT enabled, keep additional state with each packet that 857 * tells us if we need to divert or tee the packet we're building. 858 */ 859 860 static struct mbuf * 861 #ifdef IPDIVERT 862 ip_reass(m, head, fp, divinfo, divcookie) 863 #else 864 ip_reass(m, head, fp) 865 #endif 866 struct mbuf *m; 867 struct ipqhead *head; 868 struct ipq *fp; 869 #ifdef IPDIVERT 870 u_int32_t *divinfo; 871 u_int16_t *divcookie; 872 #endif 873 { 874 struct ip *ip = mtod(m, struct ip *); 875 register struct mbuf *p, *q, *nq; 876 struct mbuf *t; 877 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 878 int i, next; 879 880 /* 881 * Presence of header sizes in mbufs 882 * would confuse code below. 883 */ 884 m->m_data += hlen; 885 m->m_len -= hlen; 886 887 /* 888 * If first fragment to arrive, create a reassembly queue. 889 */ 890 if (fp == 0) { 891 /* 892 * Enforce upper bound on number of fragmented packets 893 * for which we attempt reassembly; 894 * If maxfrag is 0, never accept fragments. 895 * If maxfrag is -1, accept all fragments without limitation. 896 */ 897 if ((ip_maxfragpackets >= 0) && (ip_nfragpackets >= ip_maxfragpackets)) 898 goto dropfrag; 899 ip_nfragpackets++; 900 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 901 goto dropfrag; 902 fp = mtod(t, struct ipq *); 903 TAILQ_INSERT_HEAD(head, fp, ipq_list); 904 nipq++; 905 fp->ipq_ttl = IPFRAGTTL; 906 fp->ipq_p = ip->ip_p; 907 fp->ipq_id = ip->ip_id; 908 fp->ipq_src = ip->ip_src; 909 fp->ipq_dst = ip->ip_dst; 910 fp->ipq_frags = m; 911 m->m_nextpkt = NULL; 912 #ifdef IPDIVERT 913 fp->ipq_div_info = 0; 914 fp->ipq_div_cookie = 0; 915 #endif 916 goto inserted; 917 } 918 919 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 920 921 /* 922 * Find a segment which begins after this one does. 923 */ 924 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 925 if (GETIP(q)->ip_off > ip->ip_off) 926 break; 927 928 /* 929 * If there is a preceding segment, it may provide some of 930 * our data already. If so, drop the data from the incoming 931 * segment. If it provides all of our data, drop us, otherwise 932 * stick new segment in the proper place. 933 * 934 * If some of the data is dropped from the the preceding 935 * segment, then it's checksum is invalidated. 936 */ 937 if (p) { 938 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 939 if (i > 0) { 940 if (i >= ip->ip_len) 941 goto dropfrag; 942 m_adj(m, i); 943 m->m_pkthdr.csum_flags = 0; 944 ip->ip_off += i; 945 ip->ip_len -= i; 946 } 947 m->m_nextpkt = p->m_nextpkt; 948 p->m_nextpkt = m; 949 } else { 950 m->m_nextpkt = fp->ipq_frags; 951 fp->ipq_frags = m; 952 } 953 954 /* 955 * While we overlap succeeding segments trim them or, 956 * if they are completely covered, dequeue them. 957 */ 958 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 959 q = nq) { 960 i = (ip->ip_off + ip->ip_len) - 961 GETIP(q)->ip_off; 962 if (i < GETIP(q)->ip_len) { 963 GETIP(q)->ip_len -= i; 964 GETIP(q)->ip_off += i; 965 m_adj(q, i); 966 q->m_pkthdr.csum_flags = 0; 967 break; 968 } 969 nq = q->m_nextpkt; 970 m->m_nextpkt = nq; 971 m_freem(q); 972 } 973 974 inserted: 975 976 #ifdef IPDIVERT 977 /* 978 * Transfer firewall instructions to the fragment structure. 979 * Any fragment diverting causes the whole packet to divert. 980 */ 981 fp->ipq_div_info = *divinfo; 982 fp->ipq_div_cookie = *divcookie; 983 *divinfo = 0; 984 *divcookie = 0; 985 #endif 986 987 /* 988 * Check for complete reassembly. 989 */ 990 next = 0; 991 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 992 if (GETIP(q)->ip_off != next) 993 return (0); 994 next += GETIP(q)->ip_len; 995 } 996 /* Make sure the last packet didn't have the IP_MF flag */ 997 if (p->m_flags & M_FRAG) 998 return (0); 999 1000 /* 1001 * Reassembly is complete. Make sure the packet is a sane size. 1002 */ 1003 q = fp->ipq_frags; 1004 ip = GETIP(q); 1005 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1006 ipstat.ips_toolong++; 1007 ip_freef(head, fp); 1008 return (0); 1009 } 1010 1011 /* 1012 * Concatenate fragments. 1013 */ 1014 m = q; 1015 t = m->m_next; 1016 m->m_next = 0; 1017 m_cat(m, t); 1018 nq = q->m_nextpkt; 1019 q->m_nextpkt = 0; 1020 for (q = nq; q != NULL; q = nq) { 1021 nq = q->m_nextpkt; 1022 q->m_nextpkt = NULL; 1023 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1024 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1025 m_cat(m, q); 1026 } 1027 1028 #ifdef IPDIVERT 1029 /* 1030 * Extract firewall instructions from the fragment structure. 1031 */ 1032 *divinfo = fp->ipq_div_info; 1033 *divcookie = fp->ipq_div_cookie; 1034 #endif 1035 1036 /* 1037 * Create header for new ip packet by 1038 * modifying header of first packet; 1039 * dequeue and discard fragment reassembly header. 1040 * Make header visible. 1041 */ 1042 ip->ip_len = next; 1043 ip->ip_src = fp->ipq_src; 1044 ip->ip_dst = fp->ipq_dst; 1045 TAILQ_REMOVE(head, fp, ipq_list); 1046 nipq--; 1047 (void) m_free(dtom(fp)); 1048 ip_nfragpackets--; 1049 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1050 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1051 /* some debugging cruft by sklower, below, will go away soon */ 1052 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1053 register int plen = 0; 1054 for (t = m; t; t = t->m_next) 1055 plen += t->m_len; 1056 m->m_pkthdr.len = plen; 1057 } 1058 return (m); 1059 1060 dropfrag: 1061 #ifdef IPDIVERT 1062 *divinfo = 0; 1063 *divcookie = 0; 1064 #endif 1065 ipstat.ips_fragdropped++; 1066 m_freem(m); 1067 return (0); 1068 1069 #undef GETIP 1070 } 1071 1072 /* 1073 * Free a fragment reassembly header and all 1074 * associated datagrams. 1075 */ 1076 static void 1077 ip_freef(fhp, fp) 1078 struct ipqhead *fhp; 1079 struct ipq *fp; 1080 { 1081 register struct mbuf *q; 1082 1083 while (fp->ipq_frags) { 1084 q = fp->ipq_frags; 1085 fp->ipq_frags = q->m_nextpkt; 1086 m_freem(q); 1087 } 1088 TAILQ_REMOVE(fhp, fp, ipq_list); 1089 (void) m_free(dtom(fp)); 1090 ip_nfragpackets--; 1091 nipq--; 1092 } 1093 1094 /* 1095 * IP timer processing; 1096 * if a timer expires on a reassembly 1097 * queue, discard it. 1098 */ 1099 void 1100 ip_slowtimo() 1101 { 1102 register struct ipq *fp; 1103 int s = splnet(); 1104 int i; 1105 1106 for (i = 0; i < IPREASS_NHASH; i++) { 1107 for(fp = TAILQ_FIRST(&ipq[i]); fp;) { 1108 struct ipq *fpp; 1109 1110 fpp = fp; 1111 fp = TAILQ_NEXT(fp, ipq_list); 1112 if(--fpp->ipq_ttl == 0) { 1113 ipstat.ips_fragtimeout++; 1114 ip_freef(&ipq[i], fpp); 1115 } 1116 } 1117 } 1118 /* 1119 * If we are over the maximum number of fragments 1120 * (due to the limit being lowered), drain off 1121 * enough to get down to the new limit. 1122 */ 1123 for (i = 0; i < IPREASS_NHASH; i++) { 1124 if (ip_maxfragpackets >= 0) { 1125 while (ip_nfragpackets > ip_maxfragpackets && 1126 !TAILQ_EMPTY(&ipq[i])) { 1127 ipstat.ips_fragdropped++; 1128 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1129 } 1130 } 1131 } 1132 ipflow_slowtimo(); 1133 splx(s); 1134 } 1135 1136 /* 1137 * Drain off all datagram fragments. 1138 */ 1139 void 1140 ip_drain() 1141 { 1142 int i; 1143 1144 for (i = 0; i < IPREASS_NHASH; i++) { 1145 while(!TAILQ_EMPTY(&ipq[i])) { 1146 ipstat.ips_fragdropped++; 1147 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i])); 1148 } 1149 } 1150 in_rtqdrain(); 1151 } 1152 1153 /* 1154 * Do option processing on a datagram, 1155 * possibly discarding it if bad options are encountered, 1156 * or forwarding it if source-routed. 1157 * Returns 1 if packet has been forwarded/freed, 1158 * 0 if the packet should be processed further. 1159 */ 1160 static int 1161 ip_dooptions(m) 1162 struct mbuf *m; 1163 { 1164 register struct ip *ip = mtod(m, struct ip *); 1165 register u_char *cp; 1166 register struct ip_timestamp *ipt; 1167 register struct in_ifaddr *ia; 1168 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1169 struct in_addr *sin, dst; 1170 n_time ntime; 1171 1172 dst = ip->ip_dst; 1173 cp = (u_char *)(ip + 1); 1174 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1175 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1176 opt = cp[IPOPT_OPTVAL]; 1177 if (opt == IPOPT_EOL) 1178 break; 1179 if (opt == IPOPT_NOP) 1180 optlen = 1; 1181 else { 1182 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1183 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1184 goto bad; 1185 } 1186 optlen = cp[IPOPT_OLEN]; 1187 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1188 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1189 goto bad; 1190 } 1191 } 1192 switch (opt) { 1193 1194 default: 1195 break; 1196 1197 /* 1198 * Source routing with record. 1199 * Find interface with current destination address. 1200 * If none on this machine then drop if strictly routed, 1201 * or do nothing if loosely routed. 1202 * Record interface address and bring up next address 1203 * component. If strictly routed make sure next 1204 * address is on directly accessible net. 1205 */ 1206 case IPOPT_LSRR: 1207 case IPOPT_SSRR: 1208 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1209 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1210 goto bad; 1211 } 1212 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1213 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1214 goto bad; 1215 } 1216 ipaddr.sin_addr = ip->ip_dst; 1217 ia = (struct in_ifaddr *) 1218 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1219 if (ia == 0) { 1220 if (opt == IPOPT_SSRR) { 1221 type = ICMP_UNREACH; 1222 code = ICMP_UNREACH_SRCFAIL; 1223 goto bad; 1224 } 1225 if (!ip_dosourceroute) 1226 goto nosourcerouting; 1227 /* 1228 * Loose routing, and not at next destination 1229 * yet; nothing to do except forward. 1230 */ 1231 break; 1232 } 1233 off--; /* 0 origin */ 1234 if (off > optlen - (int)sizeof(struct in_addr)) { 1235 /* 1236 * End of source route. Should be for us. 1237 */ 1238 if (!ip_acceptsourceroute) 1239 goto nosourcerouting; 1240 save_rte(cp, ip->ip_src); 1241 break; 1242 } 1243 1244 if (!ip_dosourceroute) { 1245 if (ipforwarding) { 1246 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1247 /* 1248 * Acting as a router, so generate ICMP 1249 */ 1250 nosourcerouting: 1251 strcpy(buf, inet_ntoa(ip->ip_dst)); 1252 log(LOG_WARNING, 1253 "attempted source route from %s to %s\n", 1254 inet_ntoa(ip->ip_src), buf); 1255 type = ICMP_UNREACH; 1256 code = ICMP_UNREACH_SRCFAIL; 1257 goto bad; 1258 } else { 1259 /* 1260 * Not acting as a router, so silently drop. 1261 */ 1262 ipstat.ips_cantforward++; 1263 m_freem(m); 1264 return (1); 1265 } 1266 } 1267 1268 /* 1269 * locate outgoing interface 1270 */ 1271 (void)memcpy(&ipaddr.sin_addr, cp + off, 1272 sizeof(ipaddr.sin_addr)); 1273 1274 if (opt == IPOPT_SSRR) { 1275 #define INA struct in_ifaddr * 1276 #define SA struct sockaddr * 1277 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1278 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1279 } else 1280 ia = ip_rtaddr(ipaddr.sin_addr); 1281 if (ia == 0) { 1282 type = ICMP_UNREACH; 1283 code = ICMP_UNREACH_SRCFAIL; 1284 goto bad; 1285 } 1286 ip->ip_dst = ipaddr.sin_addr; 1287 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1288 sizeof(struct in_addr)); 1289 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1290 /* 1291 * Let ip_intr's mcast routing check handle mcast pkts 1292 */ 1293 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1294 break; 1295 1296 case IPOPT_RR: 1297 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1298 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1299 goto bad; 1300 } 1301 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1302 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1303 goto bad; 1304 } 1305 /* 1306 * If no space remains, ignore. 1307 */ 1308 off--; /* 0 origin */ 1309 if (off > optlen - (int)sizeof(struct in_addr)) 1310 break; 1311 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1312 sizeof(ipaddr.sin_addr)); 1313 /* 1314 * locate outgoing interface; if we're the destination, 1315 * use the incoming interface (should be same). 1316 */ 1317 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1318 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1319 type = ICMP_UNREACH; 1320 code = ICMP_UNREACH_HOST; 1321 goto bad; 1322 } 1323 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1324 sizeof(struct in_addr)); 1325 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1326 break; 1327 1328 case IPOPT_TS: 1329 code = cp - (u_char *)ip; 1330 ipt = (struct ip_timestamp *)cp; 1331 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) { 1332 code = (u_char *)&ipt->ipt_len - (u_char *)ip; 1333 goto bad; 1334 } 1335 if (ipt->ipt_ptr < 5) { 1336 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip; 1337 goto bad; 1338 } 1339 if (ipt->ipt_ptr > 1340 ipt->ipt_len - (int)sizeof(int32_t)) { 1341 if (++ipt->ipt_oflw == 0) { 1342 code = (u_char *)&ipt->ipt_ptr - 1343 (u_char *)ip; 1344 goto bad; 1345 } 1346 break; 1347 } 1348 sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); 1349 switch (ipt->ipt_flg) { 1350 1351 case IPOPT_TS_TSONLY: 1352 break; 1353 1354 case IPOPT_TS_TSANDADDR: 1355 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1356 sizeof(struct in_addr) > ipt->ipt_len) { 1357 code = (u_char *)&ipt->ipt_ptr - 1358 (u_char *)ip; 1359 goto bad; 1360 } 1361 ipaddr.sin_addr = dst; 1362 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1363 m->m_pkthdr.rcvif); 1364 if (ia == 0) 1365 continue; 1366 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1367 sizeof(struct in_addr)); 1368 ipt->ipt_ptr += sizeof(struct in_addr); 1369 break; 1370 1371 case IPOPT_TS_PRESPEC: 1372 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1373 sizeof(struct in_addr) > ipt->ipt_len) { 1374 code = (u_char *)&ipt->ipt_ptr - 1375 (u_char *)ip; 1376 goto bad; 1377 } 1378 (void)memcpy(&ipaddr.sin_addr, sin, 1379 sizeof(struct in_addr)); 1380 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1381 continue; 1382 ipt->ipt_ptr += sizeof(struct in_addr); 1383 break; 1384 1385 default: 1386 /* XXX can't take &ipt->ipt_flg */ 1387 code = (u_char *)&ipt->ipt_ptr - 1388 (u_char *)ip + 1; 1389 goto bad; 1390 } 1391 ntime = iptime(); 1392 (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime, 1393 sizeof(n_time)); 1394 ipt->ipt_ptr += sizeof(n_time); 1395 } 1396 } 1397 if (forward && ipforwarding) { 1398 ip_forward(m, 1); 1399 return (1); 1400 } 1401 return (0); 1402 bad: 1403 icmp_error(m, type, code, 0, 0); 1404 ipstat.ips_badoptions++; 1405 return (1); 1406 } 1407 1408 /* 1409 * Given address of next destination (final or next hop), 1410 * return internet address info of interface to be used to get there. 1411 */ 1412 static struct in_ifaddr * 1413 ip_rtaddr(dst) 1414 struct in_addr dst; 1415 { 1416 register struct sockaddr_in *sin; 1417 1418 sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; 1419 1420 if (ipforward_rt.ro_rt == 0 || 1421 !(ipforward_rt.ro_rt->rt_flags & RTF_UP) || 1422 dst.s_addr != sin->sin_addr.s_addr) { 1423 if (ipforward_rt.ro_rt) { 1424 RTFREE(ipforward_rt.ro_rt); 1425 ipforward_rt.ro_rt = 0; 1426 } 1427 sin->sin_family = AF_INET; 1428 sin->sin_len = sizeof(*sin); 1429 sin->sin_addr = dst; 1430 1431 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1432 } 1433 if (ipforward_rt.ro_rt == 0) 1434 return ((struct in_ifaddr *)0); 1435 return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); 1436 } 1437 1438 /* 1439 * Save incoming source route for use in replies, 1440 * to be picked up later by ip_srcroute if the receiver is interested. 1441 */ 1442 void 1443 save_rte(option, dst) 1444 u_char *option; 1445 struct in_addr dst; 1446 { 1447 unsigned olen; 1448 1449 olen = option[IPOPT_OLEN]; 1450 #ifdef DIAGNOSTIC 1451 if (ipprintfs) 1452 printf("save_rte: olen %d\n", olen); 1453 #endif 1454 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1455 return; 1456 bcopy(option, ip_srcrt.srcopt, olen); 1457 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1458 ip_srcrt.dst = dst; 1459 } 1460 1461 /* 1462 * Retrieve incoming source route for use in replies, 1463 * in the same form used by setsockopt. 1464 * The first hop is placed before the options, will be removed later. 1465 */ 1466 struct mbuf * 1467 ip_srcroute() 1468 { 1469 register struct in_addr *p, *q; 1470 register struct mbuf *m; 1471 1472 if (ip_nhops == 0) 1473 return ((struct mbuf *)0); 1474 m = m_get(M_DONTWAIT, MT_HEADER); 1475 if (m == 0) 1476 return ((struct mbuf *)0); 1477 1478 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1479 1480 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1481 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1482 OPTSIZ; 1483 #ifdef DIAGNOSTIC 1484 if (ipprintfs) 1485 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1486 #endif 1487 1488 /* 1489 * First save first hop for return route 1490 */ 1491 p = &ip_srcrt.route[ip_nhops - 1]; 1492 *(mtod(m, struct in_addr *)) = *p--; 1493 #ifdef DIAGNOSTIC 1494 if (ipprintfs) 1495 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1496 #endif 1497 1498 /* 1499 * Copy option fields and padding (nop) to mbuf. 1500 */ 1501 ip_srcrt.nop = IPOPT_NOP; 1502 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1503 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1504 &ip_srcrt.nop, OPTSIZ); 1505 q = (struct in_addr *)(mtod(m, caddr_t) + 1506 sizeof(struct in_addr) + OPTSIZ); 1507 #undef OPTSIZ 1508 /* 1509 * Record return path as an IP source route, 1510 * reversing the path (pointers are now aligned). 1511 */ 1512 while (p >= ip_srcrt.route) { 1513 #ifdef DIAGNOSTIC 1514 if (ipprintfs) 1515 printf(" %lx", (u_long)ntohl(q->s_addr)); 1516 #endif 1517 *q++ = *p--; 1518 } 1519 /* 1520 * Last hop goes to final destination. 1521 */ 1522 *q = ip_srcrt.dst; 1523 #ifdef DIAGNOSTIC 1524 if (ipprintfs) 1525 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1526 #endif 1527 return (m); 1528 } 1529 1530 /* 1531 * Strip out IP options, at higher 1532 * level protocol in the kernel. 1533 * Second argument is buffer to which options 1534 * will be moved, and return value is their length. 1535 * XXX should be deleted; last arg currently ignored. 1536 */ 1537 void 1538 ip_stripoptions(m, mopt) 1539 register struct mbuf *m; 1540 struct mbuf *mopt; 1541 { 1542 register int i; 1543 struct ip *ip = mtod(m, struct ip *); 1544 register caddr_t opts; 1545 int olen; 1546 1547 olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1548 opts = (caddr_t)(ip + 1); 1549 i = m->m_len - (sizeof (struct ip) + olen); 1550 bcopy(opts + olen, opts, (unsigned)i); 1551 m->m_len -= olen; 1552 if (m->m_flags & M_PKTHDR) 1553 m->m_pkthdr.len -= olen; 1554 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1555 } 1556 1557 u_char inetctlerrmap[PRC_NCMDS] = { 1558 0, 0, 0, 0, 1559 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1560 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1561 EMSGSIZE, EHOSTUNREACH, 0, 0, 1562 0, 0, 0, 0, 1563 ENOPROTOOPT, ECONNREFUSED 1564 }; 1565 1566 /* 1567 * Forward a packet. If some error occurs return the sender 1568 * an icmp packet. Note we can't always generate a meaningful 1569 * icmp message because icmp doesn't have a large enough repertoire 1570 * of codes and types. 1571 * 1572 * If not forwarding, just drop the packet. This could be confusing 1573 * if ipforwarding was zero but some routing protocol was advancing 1574 * us as a gateway to somewhere. However, we must let the routing 1575 * protocol deal with that. 1576 * 1577 * The srcrt parameter indicates whether the packet is being forwarded 1578 * via a source route. 1579 */ 1580 static void 1581 ip_forward(m, srcrt) 1582 struct mbuf *m; 1583 int srcrt; 1584 { 1585 register struct ip *ip = mtod(m, struct ip *); 1586 register struct rtentry *rt; 1587 int error, type = 0, code = 0; 1588 struct mbuf *mcopy; 1589 n_long dest; 1590 struct ifnet *destifp; 1591 #ifdef IPSEC 1592 struct ifnet dummyifp; 1593 #endif 1594 1595 dest = 0; 1596 #ifdef DIAGNOSTIC 1597 if (ipprintfs) 1598 printf("forward: src %lx dst %lx ttl %x\n", 1599 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1600 ip->ip_ttl); 1601 #endif 1602 1603 1604 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1605 ipstat.ips_cantforward++; 1606 m_freem(m); 1607 return; 1608 } 1609 #ifdef IPSTEALTH 1610 if (!ipstealth) { 1611 #endif 1612 if (ip->ip_ttl <= IPTTLDEC) { 1613 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1614 dest, 0); 1615 return; 1616 } 1617 #ifdef IPSTEALTH 1618 } 1619 #endif 1620 1621 if (ip_rtaddr(ip->ip_dst) == 0) { 1622 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1623 return; 1624 } else 1625 rt = ipforward_rt.ro_rt; 1626 1627 /* 1628 * Save the IP header and at most 8 bytes of the payload, 1629 * in case we need to generate an ICMP message to the src. 1630 * 1631 * We don't use m_copy() because it might return a reference 1632 * to a shared cluster. Both this function and ip_output() 1633 * assume exclusive access to the IP header in `m', so any 1634 * data in a cluster may change before we reach icmp_error(). 1635 */ 1636 MGET(mcopy, M_DONTWAIT, m->m_type); 1637 if (mcopy != NULL) { 1638 M_COPY_PKTHDR(mcopy, m); 1639 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 1640 (int)ip->ip_len); 1641 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1642 } 1643 1644 #ifdef IPSTEALTH 1645 if (!ipstealth) { 1646 #endif 1647 ip->ip_ttl -= IPTTLDEC; 1648 #ifdef IPSTEALTH 1649 } 1650 #endif 1651 1652 /* 1653 * If forwarding packet using same interface that it came in on, 1654 * perhaps should send a redirect to sender to shortcut a hop. 1655 * Only send redirect if source is sending directly to us, 1656 * and if packet was not source routed (or has any options). 1657 * Also, don't send redirect if forwarding using a default route 1658 * or a route modified by a redirect. 1659 */ 1660 #define satosin(sa) ((struct sockaddr_in *)(sa)) 1661 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1662 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1663 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1664 ipsendredirects && !srcrt) { 1665 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1666 u_long src = ntohl(ip->ip_src.s_addr); 1667 1668 if (RTA(rt) && 1669 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1670 if (rt->rt_flags & RTF_GATEWAY) 1671 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1672 else 1673 dest = ip->ip_dst.s_addr; 1674 /* Router requirements says to only send host redirects */ 1675 type = ICMP_REDIRECT; 1676 code = ICMP_REDIRECT_HOST; 1677 #ifdef DIAGNOSTIC 1678 if (ipprintfs) 1679 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1680 #endif 1681 } 1682 } 1683 1684 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1685 IP_FORWARDING, 0); 1686 if (error) 1687 ipstat.ips_cantforward++; 1688 else { 1689 ipstat.ips_forward++; 1690 if (type) 1691 ipstat.ips_redirectsent++; 1692 else { 1693 if (mcopy) { 1694 ipflow_create(&ipforward_rt, mcopy); 1695 m_freem(mcopy); 1696 } 1697 return; 1698 } 1699 } 1700 if (mcopy == NULL) 1701 return; 1702 destifp = NULL; 1703 1704 switch (error) { 1705 1706 case 0: /* forwarded, but need redirect */ 1707 /* type, code set above */ 1708 break; 1709 1710 case ENETUNREACH: /* shouldn't happen, checked above */ 1711 case EHOSTUNREACH: 1712 case ENETDOWN: 1713 case EHOSTDOWN: 1714 default: 1715 type = ICMP_UNREACH; 1716 code = ICMP_UNREACH_HOST; 1717 break; 1718 1719 case EMSGSIZE: 1720 type = ICMP_UNREACH; 1721 code = ICMP_UNREACH_NEEDFRAG; 1722 #ifndef IPSEC 1723 if (ipforward_rt.ro_rt) 1724 destifp = ipforward_rt.ro_rt->rt_ifp; 1725 #else 1726 /* 1727 * If the packet is routed over IPsec tunnel, tell the 1728 * originator the tunnel MTU. 1729 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1730 * XXX quickhack!!! 1731 */ 1732 if (ipforward_rt.ro_rt) { 1733 struct secpolicy *sp = NULL; 1734 int ipsecerror; 1735 int ipsechdr; 1736 struct route *ro; 1737 1738 sp = ipsec4_getpolicybyaddr(mcopy, 1739 IPSEC_DIR_OUTBOUND, 1740 IP_FORWARDING, 1741 &ipsecerror); 1742 1743 if (sp == NULL) 1744 destifp = ipforward_rt.ro_rt->rt_ifp; 1745 else { 1746 /* count IPsec header size */ 1747 ipsechdr = ipsec4_hdrsiz(mcopy, 1748 IPSEC_DIR_OUTBOUND, 1749 NULL); 1750 1751 /* 1752 * find the correct route for outer IPv4 1753 * header, compute tunnel MTU. 1754 * 1755 * XXX BUG ALERT 1756 * The "dummyifp" code relies upon the fact 1757 * that icmp_error() touches only ifp->if_mtu. 1758 */ 1759 /*XXX*/ 1760 destifp = NULL; 1761 if (sp->req != NULL 1762 && sp->req->sav != NULL 1763 && sp->req->sav->sah != NULL) { 1764 ro = &sp->req->sav->sah->sa_route; 1765 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1766 dummyifp.if_mtu = 1767 ro->ro_rt->rt_ifp->if_mtu; 1768 dummyifp.if_mtu -= ipsechdr; 1769 destifp = &dummyifp; 1770 } 1771 } 1772 1773 key_freesp(sp); 1774 } 1775 } 1776 #endif /*IPSEC*/ 1777 ipstat.ips_cantfrag++; 1778 break; 1779 1780 case ENOBUFS: 1781 type = ICMP_SOURCEQUENCH; 1782 code = 0; 1783 break; 1784 1785 case EACCES: /* ipfw denied packet */ 1786 m_freem(mcopy); 1787 return; 1788 } 1789 icmp_error(mcopy, type, code, dest, destifp); 1790 } 1791 1792 void 1793 ip_savecontrol(inp, mp, ip, m) 1794 register struct inpcb *inp; 1795 register struct mbuf **mp; 1796 register struct ip *ip; 1797 register struct mbuf *m; 1798 { 1799 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1800 struct timeval tv; 1801 1802 microtime(&tv); 1803 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1804 SCM_TIMESTAMP, SOL_SOCKET); 1805 if (*mp) 1806 mp = &(*mp)->m_next; 1807 } 1808 if (inp->inp_flags & INP_RECVDSTADDR) { 1809 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1810 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1811 if (*mp) 1812 mp = &(*mp)->m_next; 1813 } 1814 #ifdef notyet 1815 /* XXX 1816 * Moving these out of udp_input() made them even more broken 1817 * than they already were. 1818 */ 1819 /* options were tossed already */ 1820 if (inp->inp_flags & INP_RECVOPTS) { 1821 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1822 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1823 if (*mp) 1824 mp = &(*mp)->m_next; 1825 } 1826 /* ip_srcroute doesn't do what we want here, need to fix */ 1827 if (inp->inp_flags & INP_RECVRETOPTS) { 1828 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1829 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1830 if (*mp) 1831 mp = &(*mp)->m_next; 1832 } 1833 #endif 1834 if (inp->inp_flags & INP_RECVIF) { 1835 struct ifnet *ifp; 1836 struct sdlbuf { 1837 struct sockaddr_dl sdl; 1838 u_char pad[32]; 1839 } sdlbuf; 1840 struct sockaddr_dl *sdp; 1841 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1842 1843 if (((ifp = m->m_pkthdr.rcvif)) 1844 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1845 sdp = (struct sockaddr_dl *) 1846 (ifaddr_byindex(ifp->if_index)->ifa_addr); 1847 /* 1848 * Change our mind and don't try copy. 1849 */ 1850 if ((sdp->sdl_family != AF_LINK) 1851 || (sdp->sdl_len > sizeof(sdlbuf))) { 1852 goto makedummy; 1853 } 1854 bcopy(sdp, sdl2, sdp->sdl_len); 1855 } else { 1856 makedummy: 1857 sdl2->sdl_len 1858 = offsetof(struct sockaddr_dl, sdl_data[0]); 1859 sdl2->sdl_family = AF_LINK; 1860 sdl2->sdl_index = 0; 1861 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1862 } 1863 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1864 IP_RECVIF, IPPROTO_IP); 1865 if (*mp) 1866 mp = &(*mp)->m_next; 1867 } 1868 } 1869 1870 int 1871 ip_rsvp_init(struct socket *so) 1872 { 1873 if (so->so_type != SOCK_RAW || 1874 so->so_proto->pr_protocol != IPPROTO_RSVP) 1875 return EOPNOTSUPP; 1876 1877 if (ip_rsvpd != NULL) 1878 return EADDRINUSE; 1879 1880 ip_rsvpd = so; 1881 /* 1882 * This may seem silly, but we need to be sure we don't over-increment 1883 * the RSVP counter, in case something slips up. 1884 */ 1885 if (!ip_rsvp_on) { 1886 ip_rsvp_on = 1; 1887 rsvp_on++; 1888 } 1889 1890 return 0; 1891 } 1892 1893 int 1894 ip_rsvp_done(void) 1895 { 1896 ip_rsvpd = NULL; 1897 /* 1898 * This may seem silly, but we need to be sure we don't over-decrement 1899 * the RSVP counter, in case something slips up. 1900 */ 1901 if (ip_rsvp_on) { 1902 ip_rsvp_on = 0; 1903 rsvp_on--; 1904 } 1905 return 0; 1906 } 1907