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 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/mbuf.h> 51 #include <sys/malloc.h> 52 #include <sys/domain.h> 53 #include <sys/protosw.h> 54 #include <sys/socket.h> 55 #include <sys/time.h> 56 #include <sys/kernel.h> 57 #include <sys/syslog.h> 58 #include <sys/sysctl.h> 59 60 #include <net/pfil.h> 61 #include <net/if.h> 62 #include <net/if_var.h> 63 #include <net/if_dl.h> 64 #include <net/route.h> 65 #include <net/netisr.h> 66 #include <net/intrq.h> 67 68 #include <netinet/in.h> 69 #include <netinet/in_systm.h> 70 #include <netinet/in_var.h> 71 #include <netinet/ip.h> 72 #include <netinet/in_pcb.h> 73 #include <netinet/ip_var.h> 74 #include <netinet/ip_icmp.h> 75 #include <machine/in_cksum.h> 76 77 #include <netinet/ipprotosw.h> 78 79 #include <sys/socketvar.h> 80 81 #include <netinet/ip_fw.h> 82 83 #ifdef IPSEC 84 #include <netinet6/ipsec.h> 85 #include <netkey/key.h> 86 #endif 87 88 #include "faith.h" 89 #if defined(NFAITH) && NFAITH > 0 90 #include <net/if_types.h> 91 #endif 92 93 #ifdef DUMMYNET 94 #include <netinet/ip_dummynet.h> 95 #endif 96 97 int rsvp_on = 0; 98 static int ip_rsvp_on; 99 struct socket *ip_rsvpd; 100 101 int ipforwarding = 0; 102 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 103 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 104 105 static int ipsendredirects = 1; /* XXX */ 106 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 107 &ipsendredirects, 0, "Enable sending IP redirects"); 108 109 int ip_defttl = IPDEFTTL; 110 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 111 &ip_defttl, 0, "Maximum TTL on IP packets"); 112 113 static int ip_dosourceroute = 0; 114 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 115 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 116 117 static int ip_acceptsourceroute = 0; 118 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 119 CTLFLAG_RW, &ip_acceptsourceroute, 0, 120 "Enable accepting source routed IP packets"); 121 122 static int ip_keepfaith = 0; 123 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 124 &ip_keepfaith, 0, 125 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 126 127 #ifdef DIAGNOSTIC 128 static int ipprintfs = 0; 129 #endif 130 131 extern struct domain inetdomain; 132 extern struct ipprotosw inetsw[]; 133 u_char ip_protox[IPPROTO_MAX]; 134 static int ipqmaxlen = IFQ_MAXLEN; 135 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 136 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 137 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 138 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 139 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 140 141 struct ipstat ipstat; 142 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RD, 143 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 144 145 /* Packet reassembly stuff */ 146 #define IPREASS_NHASH_LOG2 6 147 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 148 #define IPREASS_HMASK (IPREASS_NHASH - 1) 149 #define IPREASS_HASH(x,y) \ 150 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 151 152 static struct ipq ipq[IPREASS_NHASH]; 153 static int nipq = 0; /* total # of reass queues */ 154 static int maxnipq; 155 const int ipintrq_present = 1; 156 157 #ifdef IPCTL_DEFMTU 158 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 159 &ip_mtu, 0, "Default MTU"); 160 #endif 161 162 #ifdef IPSTEALTH 163 static int ipstealth = 0; 164 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 165 &ipstealth, 0, ""); 166 #endif 167 168 169 /* Firewall hooks */ 170 ip_fw_chk_t *ip_fw_chk_ptr; 171 ip_fw_ctl_t *ip_fw_ctl_ptr; 172 int fw_enable = 1 ; 173 174 #ifdef DUMMYNET 175 ip_dn_ctl_t *ip_dn_ctl_ptr; 176 #endif 177 178 179 /* 180 * We need to save the IP options in case a protocol wants to respond 181 * to an incoming packet over the same route if the packet got here 182 * using IP source routing. This allows connection establishment and 183 * maintenance when the remote end is on a network that is not known 184 * to us. 185 */ 186 static int ip_nhops = 0; 187 static struct ip_srcrt { 188 struct in_addr dst; /* final destination */ 189 char nop; /* one NOP to align */ 190 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 191 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 192 } ip_srcrt; 193 194 struct sockaddr_in *ip_fw_fwd_addr; 195 196 static void save_rte __P((u_char *, struct in_addr)); 197 static int ip_dooptions __P((struct mbuf *)); 198 static void ip_forward __P((struct mbuf *, int)); 199 static void ip_freef __P((struct ipq *)); 200 #ifdef IPDIVERT 201 static struct mbuf *ip_reass __P((struct mbuf *, 202 struct ipq *, struct ipq *, u_int32_t *, u_int16_t *)); 203 #else 204 static struct mbuf *ip_reass __P((struct mbuf *, struct ipq *, struct ipq *)); 205 #endif 206 static struct in_ifaddr *ip_rtaddr __P((struct in_addr)); 207 static void ipintr __P((void)); 208 209 /* 210 * IP initialization: fill in IP protocol switch table. 211 * All protocols not implemented in kernel go to raw IP protocol handler. 212 */ 213 void 214 ip_init() 215 { 216 register struct ipprotosw *pr; 217 register int i; 218 219 TAILQ_INIT(&in_ifaddrhead); 220 pr = (struct ipprotosw *)pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 221 if (pr == 0) 222 panic("ip_init"); 223 for (i = 0; i < IPPROTO_MAX; i++) 224 ip_protox[i] = pr - inetsw; 225 for (pr = (struct ipprotosw *)inetdomain.dom_protosw; 226 pr < (struct ipprotosw *)inetdomain.dom_protoswNPROTOSW; pr++) 227 if (pr->pr_domain->dom_family == PF_INET && 228 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 229 ip_protox[pr->pr_protocol] = pr - inetsw; 230 231 for (i = 0; i < IPREASS_NHASH; i++) 232 ipq[i].next = ipq[i].prev = &ipq[i]; 233 234 maxnipq = nmbclusters/4; 235 236 ip_id = time_second & 0xffff; 237 ipintrq.ifq_maxlen = ipqmaxlen; 238 mtx_init(&ipintrq.ifq_mtx, "ip_inq", MTX_DEF); 239 240 register_netisr(NETISR_IP, ipintr); 241 } 242 243 static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 244 static struct route ipforward_rt; 245 246 /* 247 * Ip input routine. Checksum and byte swap header. If fragmented 248 * try to reassemble. Process options. Pass to next level. 249 */ 250 void 251 ip_input(struct mbuf *m) 252 { 253 struct ip *ip; 254 struct ipq *fp; 255 struct in_ifaddr *ia = NULL; 256 int i, hlen; 257 u_short sum; 258 u_int16_t divert_cookie; /* firewall cookie */ 259 #ifdef IPDIVERT 260 u_int32_t divert_info = 0; /* packet divert/tee info */ 261 #endif 262 struct ip_fw_chain *rule = NULL; 263 #ifdef PFIL_HOOKS 264 struct packet_filter_hook *pfh; 265 struct mbuf *m0; 266 int rv; 267 #endif /* PFIL_HOOKS */ 268 269 #ifdef IPDIVERT 270 /* Get and reset firewall cookie */ 271 divert_cookie = ip_divert_cookie; 272 ip_divert_cookie = 0; 273 #else 274 divert_cookie = 0; 275 #endif 276 277 #if defined(IPFIREWALL) && defined(DUMMYNET) 278 /* 279 * dummynet packet are prepended a vestigial mbuf with 280 * m_type = MT_DUMMYNET and m_data pointing to the matching 281 * rule. 282 */ 283 if (m->m_type == MT_DUMMYNET) { 284 rule = (struct ip_fw_chain *)(m->m_data) ; 285 m = m->m_next ; 286 ip = mtod(m, struct ip *); 287 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 288 goto iphack ; 289 } else 290 rule = NULL ; 291 #endif 292 293 #ifdef DIAGNOSTIC 294 if (m == NULL || (m->m_flags & M_PKTHDR) == 0) 295 panic("ip_input no HDR"); 296 #endif 297 ipstat.ips_total++; 298 299 if (m->m_pkthdr.len < sizeof(struct ip)) 300 goto tooshort; 301 302 if (m->m_len < sizeof (struct ip) && 303 (m = m_pullup(m, sizeof (struct ip))) == 0) { 304 ipstat.ips_toosmall++; 305 return; 306 } 307 ip = mtod(m, struct ip *); 308 309 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 310 ipstat.ips_badvers++; 311 goto bad; 312 } 313 314 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 315 if (hlen < sizeof(struct ip)) { /* minimum header length */ 316 ipstat.ips_badhlen++; 317 goto bad; 318 } 319 if (hlen > m->m_len) { 320 if ((m = m_pullup(m, hlen)) == 0) { 321 ipstat.ips_badhlen++; 322 return; 323 } 324 ip = mtod(m, struct ip *); 325 } 326 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 327 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 328 } else { 329 if (hlen == sizeof(struct ip)) { 330 sum = in_cksum_hdr(ip); 331 } else { 332 sum = in_cksum(m, hlen); 333 } 334 } 335 if (sum) { 336 ipstat.ips_badsum++; 337 goto bad; 338 } 339 340 /* 341 * Convert fields to host representation. 342 */ 343 NTOHS(ip->ip_len); 344 if (ip->ip_len < hlen) { 345 ipstat.ips_badlen++; 346 goto bad; 347 } 348 NTOHS(ip->ip_off); 349 350 /* 351 * Check that the amount of data in the buffers 352 * is as at least much as the IP header would have us expect. 353 * Trim mbufs if longer than we expect. 354 * Drop packet if shorter than we expect. 355 */ 356 if (m->m_pkthdr.len < ip->ip_len) { 357 tooshort: 358 ipstat.ips_tooshort++; 359 goto bad; 360 } 361 if (m->m_pkthdr.len > ip->ip_len) { 362 if (m->m_len == m->m_pkthdr.len) { 363 m->m_len = ip->ip_len; 364 m->m_pkthdr.len = ip->ip_len; 365 } else 366 m_adj(m, ip->ip_len - m->m_pkthdr.len); 367 } 368 /* 369 * IpHack's section. 370 * Right now when no processing on packet has done 371 * and it is still fresh out of network we do our black 372 * deals with it. 373 * - Firewall: deny/allow/divert 374 * - Xlate: translate packet's addr/port (NAT). 375 * - Pipe: pass pkt through dummynet. 376 * - Wrap: fake packet's addr/port <unimpl.> 377 * - Encapsulate: put it in another IP and send out. <unimp.> 378 */ 379 380 #if defined(IPFIREWALL) && defined(DUMMYNET) 381 iphack: 382 #endif 383 384 #ifdef PFIL_HOOKS 385 /* 386 * Run through list of hooks for input packets. If there are any 387 * filters which require that additional packets in the flow are 388 * not fast-forwarded, they must clear the M_CANFASTFWD flag. 389 * Note that filters must _never_ set this flag, as another filter 390 * in the list may have previously cleared it. 391 */ 392 m0 = m; 393 pfh = pfil_hook_get(PFIL_IN, &inetsw[ip_protox[IPPROTO_IP]].pr_pfh); 394 for (; pfh; pfh = pfh->pfil_link.tqe_next) 395 if (pfh->pfil_func) { 396 rv = pfh->pfil_func(ip, hlen, 397 m->m_pkthdr.rcvif, 0, &m0); 398 if (rv) 399 return; 400 m = m0; 401 if (m == NULL) 402 return; 403 ip = mtod(m, struct ip *); 404 } 405 #endif /* PFIL_HOOKS */ 406 407 if (fw_enable && ip_fw_chk_ptr) { 408 #ifdef IPFIREWALL_FORWARD 409 /* 410 * If we've been forwarded from the output side, then 411 * skip the firewall a second time 412 */ 413 if (ip_fw_fwd_addr) 414 goto ours; 415 #endif /* IPFIREWALL_FORWARD */ 416 /* 417 * See the comment in ip_output for the return values 418 * produced by the firewall. 419 */ 420 i = (*ip_fw_chk_ptr)(&ip, 421 hlen, NULL, &divert_cookie, &m, &rule, &ip_fw_fwd_addr); 422 if (m == NULL) /* Packet discarded by firewall */ 423 return; 424 if (i == 0 && ip_fw_fwd_addr == NULL) /* common case */ 425 goto pass; 426 #ifdef DUMMYNET 427 if ((i & IP_FW_PORT_DYNT_FLAG) != 0) { 428 /* Send packet to the appropriate pipe */ 429 dummynet_io(i&0xffff,DN_TO_IP_IN,m,NULL,NULL,0, rule, 430 0); 431 return; 432 } 433 #endif 434 #ifdef IPDIVERT 435 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 436 /* Divert or tee packet */ 437 divert_info = i; 438 goto ours; 439 } 440 #endif 441 #ifdef IPFIREWALL_FORWARD 442 if (i == 0 && ip_fw_fwd_addr != NULL) 443 goto pass; 444 #endif 445 /* 446 * if we get here, the packet must be dropped 447 */ 448 m_freem(m); 449 return; 450 } 451 pass: 452 453 /* 454 * Process options and, if not destined for us, 455 * ship it on. ip_dooptions returns 1 when an 456 * error was detected (causing an icmp message 457 * to be sent and the original packet to be freed). 458 */ 459 ip_nhops = 0; /* for source routed packets */ 460 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 461 #ifdef IPFIREWALL_FORWARD 462 ip_fw_fwd_addr = NULL; 463 #endif 464 return; 465 } 466 467 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 468 * matter if it is destined to another node, or whether it is 469 * a multicast one, RSVP wants it! and prevents it from being forwarded 470 * anywhere else. Also checks if the rsvp daemon is running before 471 * grabbing the packet. 472 */ 473 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 474 goto ours; 475 476 /* 477 * Check our list of addresses, to see if the packet is for us. 478 * If we don't have any addresses, assume any unicast packet 479 * we receive might be for us (and let the upper layers deal 480 * with it). 481 */ 482 if (TAILQ_EMPTY(&in_ifaddrhead) && 483 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 484 goto ours; 485 486 for (ia = TAILQ_FIRST(&in_ifaddrhead); ia; 487 ia = TAILQ_NEXT(ia, ia_link)) { 488 #define satosin(sa) ((struct sockaddr_in *)(sa)) 489 490 #ifdef BOOTP_COMPAT 491 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 492 goto ours; 493 #endif 494 #ifdef IPFIREWALL_FORWARD 495 /* 496 * If the addr to forward to is one of ours, we pretend to 497 * be the destination for this packet. 498 */ 499 if (ip_fw_fwd_addr == NULL) { 500 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 501 goto ours; 502 } else if (IA_SIN(ia)->sin_addr.s_addr == 503 ip_fw_fwd_addr->sin_addr.s_addr) 504 goto ours; 505 #else 506 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 507 goto ours; 508 #endif 509 if (ia->ia_ifp && ia->ia_ifp->if_flags & IFF_BROADCAST) { 510 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 511 ip->ip_dst.s_addr) 512 goto ours; 513 if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr) 514 goto ours; 515 } 516 } 517 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 518 struct in_multi *inm; 519 if (ip_mrouter) { 520 /* 521 * If we are acting as a multicast router, all 522 * incoming multicast packets are passed to the 523 * kernel-level multicast forwarding function. 524 * The packet is returned (relatively) intact; if 525 * ip_mforward() returns a non-zero value, the packet 526 * must be discarded, else it may be accepted below. 527 */ 528 if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 529 ipstat.ips_cantforward++; 530 m_freem(m); 531 return; 532 } 533 534 /* 535 * The process-level routing demon needs to receive 536 * all multicast IGMP packets, whether or not this 537 * host belongs to their destination groups. 538 */ 539 if (ip->ip_p == IPPROTO_IGMP) 540 goto ours; 541 ipstat.ips_forward++; 542 } 543 /* 544 * See if we belong to the destination multicast group on the 545 * arrival interface. 546 */ 547 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 548 if (inm == NULL) { 549 ipstat.ips_notmember++; 550 m_freem(m); 551 return; 552 } 553 goto ours; 554 } 555 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 556 goto ours; 557 if (ip->ip_dst.s_addr == INADDR_ANY) 558 goto ours; 559 560 #if defined(NFAITH) && 0 < NFAITH 561 /* 562 * FAITH(Firewall Aided Internet Translator) 563 */ 564 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 565 if (ip_keepfaith) { 566 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 567 goto ours; 568 } 569 m_freem(m); 570 return; 571 } 572 #endif 573 /* 574 * Not for us; forward if possible and desirable. 575 */ 576 if (ipforwarding == 0) { 577 ipstat.ips_cantforward++; 578 m_freem(m); 579 } else 580 ip_forward(m, 0); 581 #ifdef IPFIREWALL_FORWARD 582 ip_fw_fwd_addr = NULL; 583 #endif 584 return; 585 586 ours: 587 /* Count the packet in the ip address stats */ 588 if (ia != NULL) { 589 ia->ia_ifa.if_ipackets++; 590 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 591 } 592 593 /* 594 * If offset or IP_MF are set, must reassemble. 595 * Otherwise, nothing need be done. 596 * (We could look in the reassembly queue to see 597 * if the packet was previously fragmented, 598 * but it's not worth the time; just let them time out.) 599 */ 600 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 601 602 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 603 /* 604 * Look for queue of fragments 605 * of this datagram. 606 */ 607 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 608 if (ip->ip_id == fp->ipq_id && 609 ip->ip_src.s_addr == fp->ipq_src.s_addr && 610 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 611 ip->ip_p == fp->ipq_p) 612 goto found; 613 614 fp = 0; 615 616 /* check if there's a place for the new queue */ 617 if (nipq > maxnipq) { 618 /* 619 * drop something from the tail of the current queue 620 * before proceeding further 621 */ 622 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 623 for (i = 0; i < IPREASS_NHASH; i++) { 624 if (ipq[i].prev != &ipq[i]) { 625 ip_freef(ipq[i].prev); 626 break; 627 } 628 } 629 } else 630 ip_freef(ipq[sum].prev); 631 } 632 found: 633 /* 634 * Adjust ip_len to not reflect header, 635 * convert offset of this to bytes. 636 */ 637 ip->ip_len -= hlen; 638 if (ip->ip_off & IP_MF) { 639 /* 640 * Make sure that fragments have a data length 641 * that's a non-zero multiple of 8 bytes. 642 */ 643 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 644 ipstat.ips_toosmall++; /* XXX */ 645 goto bad; 646 } 647 m->m_flags |= M_FRAG; 648 } 649 ip->ip_off <<= 3; 650 651 /* 652 * Attempt reassembly; if it succeeds, proceed. 653 */ 654 ipstat.ips_fragments++; 655 m->m_pkthdr.header = ip; 656 #ifdef IPDIVERT 657 m = ip_reass(m, 658 fp, &ipq[sum], &divert_info, &divert_cookie); 659 #else 660 m = ip_reass(m, fp, &ipq[sum]); 661 #endif 662 if (m == 0) { 663 #ifdef IPFIREWALL_FORWARD 664 ip_fw_fwd_addr = NULL; 665 #endif 666 return; 667 } 668 ipstat.ips_reassembled++; 669 ip = mtod(m, struct ip *); 670 /* Get the header length of the reassembled packet */ 671 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 672 #ifdef IPDIVERT 673 /* Restore original checksum before diverting packet */ 674 if (divert_info != 0) { 675 ip->ip_len += hlen; 676 HTONS(ip->ip_len); 677 HTONS(ip->ip_off); 678 ip->ip_sum = 0; 679 if (hlen == sizeof(struct ip)) 680 ip->ip_sum = in_cksum_hdr(ip); 681 else 682 ip->ip_sum = in_cksum(m, hlen); 683 NTOHS(ip->ip_off); 684 NTOHS(ip->ip_len); 685 ip->ip_len -= hlen; 686 } 687 #endif 688 } else 689 ip->ip_len -= hlen; 690 691 #ifdef IPDIVERT 692 /* 693 * Divert or tee packet to the divert protocol if required. 694 * 695 * If divert_info is zero then cookie should be too, so we shouldn't 696 * need to clear them here. Assume divert_packet() does so also. 697 */ 698 if (divert_info != 0) { 699 struct mbuf *clone = NULL; 700 701 /* Clone packet if we're doing a 'tee' */ 702 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 703 clone = m_dup(m, M_DONTWAIT); 704 705 /* Restore packet header fields to original values */ 706 ip->ip_len += hlen; 707 HTONS(ip->ip_len); 708 HTONS(ip->ip_off); 709 710 /* Deliver packet to divert input routine */ 711 ip_divert_cookie = divert_cookie; 712 divert_packet(m, 1, divert_info & 0xffff); 713 ipstat.ips_delivered++; 714 715 /* If 'tee', continue with original packet */ 716 if (clone == NULL) 717 return; 718 m = clone; 719 ip = mtod(m, struct ip *); 720 } 721 #endif 722 723 /* 724 * Switch out to protocol's input routine. 725 */ 726 ipstat.ips_delivered++; 727 { 728 int off = hlen, nh = ip->ip_p; 729 730 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, off, nh); 731 #ifdef IPFIREWALL_FORWARD 732 ip_fw_fwd_addr = NULL; /* tcp needed it */ 733 #endif 734 return; 735 } 736 bad: 737 #ifdef IPFIREWALL_FORWARD 738 ip_fw_fwd_addr = NULL; 739 #endif 740 m_freem(m); 741 } 742 743 /* 744 * IP software interrupt routine - to go away sometime soon 745 */ 746 static void 747 ipintr(void) 748 { 749 struct mbuf *m; 750 751 while (1) { 752 IF_DEQUEUE(&ipintrq, m); 753 if (m == 0) 754 return; 755 ip_input(m); 756 } 757 } 758 759 /* 760 * Take incoming datagram fragment and try to reassemble it into 761 * whole datagram. If a chain for reassembly of this datagram already 762 * exists, then it is given as fp; otherwise have to make a chain. 763 * 764 * When IPDIVERT enabled, keep additional state with each packet that 765 * tells us if we need to divert or tee the packet we're building. 766 */ 767 768 static struct mbuf * 769 #ifdef IPDIVERT 770 ip_reass(m, fp, where, divinfo, divcookie) 771 #else 772 ip_reass(m, fp, where) 773 #endif 774 register struct mbuf *m; 775 register struct ipq *fp; 776 struct ipq *where; 777 #ifdef IPDIVERT 778 u_int32_t *divinfo; 779 u_int16_t *divcookie; 780 #endif 781 { 782 struct ip *ip = mtod(m, struct ip *); 783 register struct mbuf *p, *q, *nq; 784 struct mbuf *t; 785 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 786 int i, next; 787 788 /* 789 * Presence of header sizes in mbufs 790 * would confuse code below. 791 */ 792 m->m_data += hlen; 793 m->m_len -= hlen; 794 795 /* 796 * If first fragment to arrive, create a reassembly queue. 797 */ 798 if (fp == 0) { 799 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 800 goto dropfrag; 801 fp = mtod(t, struct ipq *); 802 insque(fp, where); 803 nipq++; 804 fp->ipq_ttl = IPFRAGTTL; 805 fp->ipq_p = ip->ip_p; 806 fp->ipq_id = ip->ip_id; 807 fp->ipq_src = ip->ip_src; 808 fp->ipq_dst = ip->ip_dst; 809 fp->ipq_frags = m; 810 m->m_nextpkt = NULL; 811 #ifdef IPDIVERT 812 fp->ipq_div_info = 0; 813 fp->ipq_div_cookie = 0; 814 #endif 815 goto inserted; 816 } 817 818 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 819 820 /* 821 * Find a segment which begins after this one does. 822 */ 823 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 824 if (GETIP(q)->ip_off > ip->ip_off) 825 break; 826 827 /* 828 * If there is a preceding segment, it may provide some of 829 * our data already. If so, drop the data from the incoming 830 * segment. If it provides all of our data, drop us, otherwise 831 * stick new segment in the proper place. 832 * 833 * If some of the data is dropped from the the preceding 834 * segment, then it's checksum is invalidated. 835 */ 836 if (p) { 837 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 838 if (i > 0) { 839 if (i >= ip->ip_len) 840 goto dropfrag; 841 m_adj(m, i); 842 m->m_pkthdr.csum_flags = 0; 843 ip->ip_off += i; 844 ip->ip_len -= i; 845 } 846 m->m_nextpkt = p->m_nextpkt; 847 p->m_nextpkt = m; 848 } else { 849 m->m_nextpkt = fp->ipq_frags; 850 fp->ipq_frags = m; 851 } 852 853 /* 854 * While we overlap succeeding segments trim them or, 855 * if they are completely covered, dequeue them. 856 */ 857 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 858 q = nq) { 859 i = (ip->ip_off + ip->ip_len) - 860 GETIP(q)->ip_off; 861 if (i < GETIP(q)->ip_len) { 862 GETIP(q)->ip_len -= i; 863 GETIP(q)->ip_off += i; 864 m_adj(q, i); 865 q->m_pkthdr.csum_flags = 0; 866 break; 867 } 868 nq = q->m_nextpkt; 869 m->m_nextpkt = nq; 870 m_freem(q); 871 } 872 873 inserted: 874 875 #ifdef IPDIVERT 876 /* 877 * Transfer firewall instructions to the fragment structure. 878 * Any fragment diverting causes the whole packet to divert. 879 */ 880 fp->ipq_div_info = *divinfo; 881 fp->ipq_div_cookie = *divcookie; 882 *divinfo = 0; 883 *divcookie = 0; 884 #endif 885 886 /* 887 * Check for complete reassembly. 888 */ 889 next = 0; 890 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 891 if (GETIP(q)->ip_off != next) 892 return (0); 893 next += GETIP(q)->ip_len; 894 } 895 /* Make sure the last packet didn't have the IP_MF flag */ 896 if (p->m_flags & M_FRAG) 897 return (0); 898 899 /* 900 * Reassembly is complete. Make sure the packet is a sane size. 901 */ 902 q = fp->ipq_frags; 903 ip = GETIP(q); 904 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 905 ipstat.ips_toolong++; 906 ip_freef(fp); 907 return (0); 908 } 909 910 /* 911 * Concatenate fragments. 912 */ 913 m = q; 914 t = m->m_next; 915 m->m_next = 0; 916 m_cat(m, t); 917 nq = q->m_nextpkt; 918 q->m_nextpkt = 0; 919 for (q = nq; q != NULL; q = nq) { 920 nq = q->m_nextpkt; 921 q->m_nextpkt = NULL; 922 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 923 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 924 m_cat(m, q); 925 } 926 927 #ifdef IPDIVERT 928 /* 929 * Extract firewall instructions from the fragment structure. 930 */ 931 *divinfo = fp->ipq_div_info; 932 *divcookie = fp->ipq_div_cookie; 933 #endif 934 935 /* 936 * Create header for new ip packet by 937 * modifying header of first packet; 938 * dequeue and discard fragment reassembly header. 939 * Make header visible. 940 */ 941 ip->ip_len = next; 942 ip->ip_src = fp->ipq_src; 943 ip->ip_dst = fp->ipq_dst; 944 remque(fp); 945 nipq--; 946 (void) m_free(dtom(fp)); 947 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 948 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 949 /* some debugging cruft by sklower, below, will go away soon */ 950 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 951 register int plen = 0; 952 for (t = m; t; t = t->m_next) 953 plen += t->m_len; 954 m->m_pkthdr.len = plen; 955 } 956 return (m); 957 958 dropfrag: 959 #ifdef IPDIVERT 960 *divinfo = 0; 961 *divcookie = 0; 962 #endif 963 ipstat.ips_fragdropped++; 964 m_freem(m); 965 return (0); 966 967 #undef GETIP 968 } 969 970 /* 971 * Free a fragment reassembly header and all 972 * associated datagrams. 973 */ 974 static void 975 ip_freef(fp) 976 struct ipq *fp; 977 { 978 register struct mbuf *q; 979 980 while (fp->ipq_frags) { 981 q = fp->ipq_frags; 982 fp->ipq_frags = q->m_nextpkt; 983 m_freem(q); 984 } 985 remque(fp); 986 (void) m_free(dtom(fp)); 987 nipq--; 988 } 989 990 /* 991 * IP timer processing; 992 * if a timer expires on a reassembly 993 * queue, discard it. 994 */ 995 void 996 ip_slowtimo() 997 { 998 register struct ipq *fp; 999 int s = splnet(); 1000 int i; 1001 1002 for (i = 0; i < IPREASS_NHASH; i++) { 1003 fp = ipq[i].next; 1004 if (fp == 0) 1005 continue; 1006 while (fp != &ipq[i]) { 1007 --fp->ipq_ttl; 1008 fp = fp->next; 1009 if (fp->prev->ipq_ttl == 0) { 1010 ipstat.ips_fragtimeout++; 1011 ip_freef(fp->prev); 1012 } 1013 } 1014 } 1015 ipflow_slowtimo(); 1016 splx(s); 1017 } 1018 1019 /* 1020 * Drain off all datagram fragments. 1021 */ 1022 void 1023 ip_drain() 1024 { 1025 int i; 1026 1027 for (i = 0; i < IPREASS_NHASH; i++) { 1028 while (ipq[i].next != &ipq[i]) { 1029 ipstat.ips_fragdropped++; 1030 ip_freef(ipq[i].next); 1031 } 1032 } 1033 in_rtqdrain(); 1034 } 1035 1036 /* 1037 * Do option processing on a datagram, 1038 * possibly discarding it if bad options are encountered, 1039 * or forwarding it if source-routed. 1040 * Returns 1 if packet has been forwarded/freed, 1041 * 0 if the packet should be processed further. 1042 */ 1043 static int 1044 ip_dooptions(m) 1045 struct mbuf *m; 1046 { 1047 register struct ip *ip = mtod(m, struct ip *); 1048 register u_char *cp; 1049 register struct ip_timestamp *ipt; 1050 register struct in_ifaddr *ia; 1051 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1052 struct in_addr *sin, dst; 1053 n_time ntime; 1054 1055 dst = ip->ip_dst; 1056 cp = (u_char *)(ip + 1); 1057 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1058 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1059 opt = cp[IPOPT_OPTVAL]; 1060 if (opt == IPOPT_EOL) 1061 break; 1062 if (opt == IPOPT_NOP) 1063 optlen = 1; 1064 else { 1065 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1066 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1067 goto bad; 1068 } 1069 optlen = cp[IPOPT_OLEN]; 1070 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1071 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1072 goto bad; 1073 } 1074 } 1075 switch (opt) { 1076 1077 default: 1078 break; 1079 1080 /* 1081 * Source routing with record. 1082 * Find interface with current destination address. 1083 * If none on this machine then drop if strictly routed, 1084 * or do nothing if loosely routed. 1085 * Record interface address and bring up next address 1086 * component. If strictly routed make sure next 1087 * address is on directly accessible net. 1088 */ 1089 case IPOPT_LSRR: 1090 case IPOPT_SSRR: 1091 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1092 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1093 goto bad; 1094 } 1095 ipaddr.sin_addr = ip->ip_dst; 1096 ia = (struct in_ifaddr *) 1097 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1098 if (ia == 0) { 1099 if (opt == IPOPT_SSRR) { 1100 type = ICMP_UNREACH; 1101 code = ICMP_UNREACH_SRCFAIL; 1102 goto bad; 1103 } 1104 if (!ip_dosourceroute) 1105 goto nosourcerouting; 1106 /* 1107 * Loose routing, and not at next destination 1108 * yet; nothing to do except forward. 1109 */ 1110 break; 1111 } 1112 off--; /* 0 origin */ 1113 if (off > optlen - (int)sizeof(struct in_addr)) { 1114 /* 1115 * End of source route. Should be for us. 1116 */ 1117 if (!ip_acceptsourceroute) 1118 goto nosourcerouting; 1119 save_rte(cp, ip->ip_src); 1120 break; 1121 } 1122 1123 if (!ip_dosourceroute) { 1124 if (ipforwarding) { 1125 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1126 /* 1127 * Acting as a router, so generate ICMP 1128 */ 1129 nosourcerouting: 1130 strcpy(buf, inet_ntoa(ip->ip_dst)); 1131 log(LOG_WARNING, 1132 "attempted source route from %s to %s\n", 1133 inet_ntoa(ip->ip_src), buf); 1134 type = ICMP_UNREACH; 1135 code = ICMP_UNREACH_SRCFAIL; 1136 goto bad; 1137 } else { 1138 /* 1139 * Not acting as a router, so silently drop. 1140 */ 1141 ipstat.ips_cantforward++; 1142 m_freem(m); 1143 return (1); 1144 } 1145 } 1146 1147 /* 1148 * locate outgoing interface 1149 */ 1150 (void)memcpy(&ipaddr.sin_addr, cp + off, 1151 sizeof(ipaddr.sin_addr)); 1152 1153 if (opt == IPOPT_SSRR) { 1154 #define INA struct in_ifaddr * 1155 #define SA struct sockaddr * 1156 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1157 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1158 } else 1159 ia = ip_rtaddr(ipaddr.sin_addr); 1160 if (ia == 0) { 1161 type = ICMP_UNREACH; 1162 code = ICMP_UNREACH_SRCFAIL; 1163 goto bad; 1164 } 1165 ip->ip_dst = ipaddr.sin_addr; 1166 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1167 sizeof(struct in_addr)); 1168 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1169 /* 1170 * Let ip_intr's mcast routing check handle mcast pkts 1171 */ 1172 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1173 break; 1174 1175 case IPOPT_RR: 1176 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1177 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1178 goto bad; 1179 } 1180 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1181 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1182 goto bad; 1183 } 1184 /* 1185 * If no space remains, ignore. 1186 */ 1187 off--; /* 0 origin */ 1188 if (off > optlen - (int)sizeof(struct in_addr)) 1189 break; 1190 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1191 sizeof(ipaddr.sin_addr)); 1192 /* 1193 * locate outgoing interface; if we're the destination, 1194 * use the incoming interface (should be same). 1195 */ 1196 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1197 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1198 type = ICMP_UNREACH; 1199 code = ICMP_UNREACH_HOST; 1200 goto bad; 1201 } 1202 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1203 sizeof(struct in_addr)); 1204 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1205 break; 1206 1207 case IPOPT_TS: 1208 code = cp - (u_char *)ip; 1209 ipt = (struct ip_timestamp *)cp; 1210 if (ipt->ipt_len < 5) 1211 goto bad; 1212 if (ipt->ipt_ptr > 1213 ipt->ipt_len - (int)sizeof(int32_t)) { 1214 if (++ipt->ipt_oflw == 0) 1215 goto bad; 1216 break; 1217 } 1218 sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); 1219 switch (ipt->ipt_flg) { 1220 1221 case IPOPT_TS_TSONLY: 1222 break; 1223 1224 case IPOPT_TS_TSANDADDR: 1225 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1226 sizeof(struct in_addr) > ipt->ipt_len) 1227 goto bad; 1228 ipaddr.sin_addr = dst; 1229 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1230 m->m_pkthdr.rcvif); 1231 if (ia == 0) 1232 continue; 1233 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1234 sizeof(struct in_addr)); 1235 ipt->ipt_ptr += sizeof(struct in_addr); 1236 break; 1237 1238 case IPOPT_TS_PRESPEC: 1239 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1240 sizeof(struct in_addr) > ipt->ipt_len) 1241 goto bad; 1242 (void)memcpy(&ipaddr.sin_addr, sin, 1243 sizeof(struct in_addr)); 1244 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1245 continue; 1246 ipt->ipt_ptr += sizeof(struct in_addr); 1247 break; 1248 1249 default: 1250 goto bad; 1251 } 1252 ntime = iptime(); 1253 (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime, 1254 sizeof(n_time)); 1255 ipt->ipt_ptr += sizeof(n_time); 1256 } 1257 } 1258 if (forward && ipforwarding) { 1259 ip_forward(m, 1); 1260 return (1); 1261 } 1262 return (0); 1263 bad: 1264 icmp_error(m, type, code, 0, 0); 1265 ipstat.ips_badoptions++; 1266 return (1); 1267 } 1268 1269 /* 1270 * Given address of next destination (final or next hop), 1271 * return internet address info of interface to be used to get there. 1272 */ 1273 static struct in_ifaddr * 1274 ip_rtaddr(dst) 1275 struct in_addr dst; 1276 { 1277 register struct sockaddr_in *sin; 1278 1279 sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; 1280 1281 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 1282 if (ipforward_rt.ro_rt) { 1283 RTFREE(ipforward_rt.ro_rt); 1284 ipforward_rt.ro_rt = 0; 1285 } 1286 sin->sin_family = AF_INET; 1287 sin->sin_len = sizeof(*sin); 1288 sin->sin_addr = dst; 1289 1290 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1291 } 1292 if (ipforward_rt.ro_rt == 0) 1293 return ((struct in_ifaddr *)0); 1294 return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); 1295 } 1296 1297 /* 1298 * Save incoming source route for use in replies, 1299 * to be picked up later by ip_srcroute if the receiver is interested. 1300 */ 1301 void 1302 save_rte(option, dst) 1303 u_char *option; 1304 struct in_addr dst; 1305 { 1306 unsigned olen; 1307 1308 olen = option[IPOPT_OLEN]; 1309 #ifdef DIAGNOSTIC 1310 if (ipprintfs) 1311 printf("save_rte: olen %d\n", olen); 1312 #endif 1313 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1314 return; 1315 bcopy(option, ip_srcrt.srcopt, olen); 1316 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1317 ip_srcrt.dst = dst; 1318 } 1319 1320 /* 1321 * Retrieve incoming source route for use in replies, 1322 * in the same form used by setsockopt. 1323 * The first hop is placed before the options, will be removed later. 1324 */ 1325 struct mbuf * 1326 ip_srcroute() 1327 { 1328 register struct in_addr *p, *q; 1329 register struct mbuf *m; 1330 1331 if (ip_nhops == 0) 1332 return ((struct mbuf *)0); 1333 m = m_get(M_DONTWAIT, MT_HEADER); 1334 if (m == 0) 1335 return ((struct mbuf *)0); 1336 1337 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1338 1339 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1340 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1341 OPTSIZ; 1342 #ifdef DIAGNOSTIC 1343 if (ipprintfs) 1344 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1345 #endif 1346 1347 /* 1348 * First save first hop for return route 1349 */ 1350 p = &ip_srcrt.route[ip_nhops - 1]; 1351 *(mtod(m, struct in_addr *)) = *p--; 1352 #ifdef DIAGNOSTIC 1353 if (ipprintfs) 1354 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1355 #endif 1356 1357 /* 1358 * Copy option fields and padding (nop) to mbuf. 1359 */ 1360 ip_srcrt.nop = IPOPT_NOP; 1361 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1362 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1363 &ip_srcrt.nop, OPTSIZ); 1364 q = (struct in_addr *)(mtod(m, caddr_t) + 1365 sizeof(struct in_addr) + OPTSIZ); 1366 #undef OPTSIZ 1367 /* 1368 * Record return path as an IP source route, 1369 * reversing the path (pointers are now aligned). 1370 */ 1371 while (p >= ip_srcrt.route) { 1372 #ifdef DIAGNOSTIC 1373 if (ipprintfs) 1374 printf(" %lx", (u_long)ntohl(q->s_addr)); 1375 #endif 1376 *q++ = *p--; 1377 } 1378 /* 1379 * Last hop goes to final destination. 1380 */ 1381 *q = ip_srcrt.dst; 1382 #ifdef DIAGNOSTIC 1383 if (ipprintfs) 1384 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1385 #endif 1386 return (m); 1387 } 1388 1389 /* 1390 * Strip out IP options, at higher 1391 * level protocol in the kernel. 1392 * Second argument is buffer to which options 1393 * will be moved, and return value is their length. 1394 * XXX should be deleted; last arg currently ignored. 1395 */ 1396 void 1397 ip_stripoptions(m, mopt) 1398 register struct mbuf *m; 1399 struct mbuf *mopt; 1400 { 1401 register int i; 1402 struct ip *ip = mtod(m, struct ip *); 1403 register caddr_t opts; 1404 int olen; 1405 1406 olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1407 opts = (caddr_t)(ip + 1); 1408 i = m->m_len - (sizeof (struct ip) + olen); 1409 bcopy(opts + olen, opts, (unsigned)i); 1410 m->m_len -= olen; 1411 if (m->m_flags & M_PKTHDR) 1412 m->m_pkthdr.len -= olen; 1413 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1414 } 1415 1416 u_char inetctlerrmap[PRC_NCMDS] = { 1417 0, 0, 0, 0, 1418 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1419 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1420 EMSGSIZE, EHOSTUNREACH, 0, 0, 1421 0, 0, 0, 0, 1422 ENOPROTOOPT 1423 }; 1424 1425 /* 1426 * Forward a packet. If some error occurs return the sender 1427 * an icmp packet. Note we can't always generate a meaningful 1428 * icmp message because icmp doesn't have a large enough repertoire 1429 * of codes and types. 1430 * 1431 * If not forwarding, just drop the packet. This could be confusing 1432 * if ipforwarding was zero but some routing protocol was advancing 1433 * us as a gateway to somewhere. However, we must let the routing 1434 * protocol deal with that. 1435 * 1436 * The srcrt parameter indicates whether the packet is being forwarded 1437 * via a source route. 1438 */ 1439 static void 1440 ip_forward(m, srcrt) 1441 struct mbuf *m; 1442 int srcrt; 1443 { 1444 register struct ip *ip = mtod(m, struct ip *); 1445 register struct sockaddr_in *sin; 1446 register struct rtentry *rt; 1447 int error, type = 0, code = 0; 1448 struct mbuf *mcopy; 1449 n_long dest; 1450 struct ifnet *destifp; 1451 #ifdef IPSEC 1452 struct ifnet dummyifp; 1453 #endif 1454 1455 dest = 0; 1456 #ifdef DIAGNOSTIC 1457 if (ipprintfs) 1458 printf("forward: src %lx dst %lx ttl %x\n", 1459 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1460 ip->ip_ttl); 1461 #endif 1462 1463 1464 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1465 ipstat.ips_cantforward++; 1466 m_freem(m); 1467 return; 1468 } 1469 #ifdef IPSTEALTH 1470 if (!ipstealth) { 1471 #endif 1472 if (ip->ip_ttl <= IPTTLDEC) { 1473 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1474 dest, 0); 1475 return; 1476 } 1477 #ifdef IPSTEALTH 1478 } 1479 #endif 1480 1481 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1482 if ((rt = ipforward_rt.ro_rt) == 0 || 1483 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1484 if (ipforward_rt.ro_rt) { 1485 RTFREE(ipforward_rt.ro_rt); 1486 ipforward_rt.ro_rt = 0; 1487 } 1488 sin->sin_family = AF_INET; 1489 sin->sin_len = sizeof(*sin); 1490 sin->sin_addr = ip->ip_dst; 1491 1492 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1493 if (ipforward_rt.ro_rt == 0) { 1494 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1495 return; 1496 } 1497 rt = ipforward_rt.ro_rt; 1498 } 1499 1500 /* 1501 * Save at most 64 bytes of the packet in case 1502 * we need to generate an ICMP message to the src. 1503 */ 1504 mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); 1505 if (mcopy && (mcopy->m_flags & M_EXT)) 1506 m_copydata(mcopy, 0, sizeof(struct ip), mtod(mcopy, caddr_t)); 1507 1508 #ifdef IPSTEALTH 1509 if (!ipstealth) { 1510 #endif 1511 ip->ip_ttl -= IPTTLDEC; 1512 #ifdef IPSTEALTH 1513 } 1514 #endif 1515 1516 /* 1517 * If forwarding packet using same interface that it came in on, 1518 * perhaps should send a redirect to sender to shortcut a hop. 1519 * Only send redirect if source is sending directly to us, 1520 * and if packet was not source routed (or has any options). 1521 * Also, don't send redirect if forwarding using a default route 1522 * or a route modified by a redirect. 1523 */ 1524 #define satosin(sa) ((struct sockaddr_in *)(sa)) 1525 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1526 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1527 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1528 ipsendredirects && !srcrt) { 1529 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1530 u_long src = ntohl(ip->ip_src.s_addr); 1531 1532 if (RTA(rt) && 1533 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1534 if (rt->rt_flags & RTF_GATEWAY) 1535 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1536 else 1537 dest = ip->ip_dst.s_addr; 1538 /* Router requirements says to only send host redirects */ 1539 type = ICMP_REDIRECT; 1540 code = ICMP_REDIRECT_HOST; 1541 #ifdef DIAGNOSTIC 1542 if (ipprintfs) 1543 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1544 #endif 1545 } 1546 } 1547 1548 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1549 IP_FORWARDING, 0); 1550 if (error) 1551 ipstat.ips_cantforward++; 1552 else { 1553 ipstat.ips_forward++; 1554 if (type) 1555 ipstat.ips_redirectsent++; 1556 else { 1557 if (mcopy) { 1558 ipflow_create(&ipforward_rt, mcopy); 1559 m_freem(mcopy); 1560 } 1561 return; 1562 } 1563 } 1564 if (mcopy == NULL) 1565 return; 1566 destifp = NULL; 1567 1568 switch (error) { 1569 1570 case 0: /* forwarded, but need redirect */ 1571 /* type, code set above */ 1572 break; 1573 1574 case ENETUNREACH: /* shouldn't happen, checked above */ 1575 case EHOSTUNREACH: 1576 case ENETDOWN: 1577 case EHOSTDOWN: 1578 default: 1579 type = ICMP_UNREACH; 1580 code = ICMP_UNREACH_HOST; 1581 break; 1582 1583 case EMSGSIZE: 1584 type = ICMP_UNREACH; 1585 code = ICMP_UNREACH_NEEDFRAG; 1586 #ifndef IPSEC 1587 if (ipforward_rt.ro_rt) 1588 destifp = ipforward_rt.ro_rt->rt_ifp; 1589 #else 1590 /* 1591 * If the packet is routed over IPsec tunnel, tell the 1592 * originator the tunnel MTU. 1593 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1594 * XXX quickhack!!! 1595 */ 1596 if (ipforward_rt.ro_rt) { 1597 struct secpolicy *sp = NULL; 1598 int ipsecerror; 1599 int ipsechdr; 1600 struct route *ro; 1601 1602 sp = ipsec4_getpolicybyaddr(mcopy, 1603 IPSEC_DIR_OUTBOUND, 1604 IP_FORWARDING, 1605 &ipsecerror); 1606 1607 if (sp == NULL) 1608 destifp = ipforward_rt.ro_rt->rt_ifp; 1609 else { 1610 /* count IPsec header size */ 1611 ipsechdr = ipsec4_hdrsiz(mcopy, 1612 IPSEC_DIR_OUTBOUND, 1613 NULL); 1614 1615 /* 1616 * find the correct route for outer IPv4 1617 * header, compute tunnel MTU. 1618 * 1619 * XXX BUG ALERT 1620 * The "dummyifp" code relies upon the fact 1621 * that icmp_error() touches only ifp->if_mtu. 1622 */ 1623 /*XXX*/ 1624 destifp = NULL; 1625 if (sp->req != NULL 1626 && sp->req->sav != NULL 1627 && sp->req->sav->sah != NULL) { 1628 ro = &sp->req->sav->sah->sa_route; 1629 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1630 dummyifp.if_mtu = 1631 ro->ro_rt->rt_ifp->if_mtu; 1632 dummyifp.if_mtu -= ipsechdr; 1633 destifp = &dummyifp; 1634 } 1635 } 1636 1637 key_freesp(sp); 1638 } 1639 } 1640 #endif /*IPSEC*/ 1641 ipstat.ips_cantfrag++; 1642 break; 1643 1644 case ENOBUFS: 1645 type = ICMP_SOURCEQUENCH; 1646 code = 0; 1647 break; 1648 1649 case EACCES: /* ipfw denied packet */ 1650 m_freem(mcopy); 1651 return; 1652 } 1653 if (mcopy->m_flags & M_EXT) 1654 m_copyback(mcopy, 0, sizeof(struct ip), mtod(mcopy, caddr_t)); 1655 icmp_error(mcopy, type, code, dest, destifp); 1656 } 1657 1658 void 1659 ip_savecontrol(inp, mp, ip, m) 1660 register struct inpcb *inp; 1661 register struct mbuf **mp; 1662 register struct ip *ip; 1663 register struct mbuf *m; 1664 { 1665 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1666 struct timeval tv; 1667 1668 microtime(&tv); 1669 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1670 SCM_TIMESTAMP, SOL_SOCKET); 1671 if (*mp) 1672 mp = &(*mp)->m_next; 1673 } 1674 if (inp->inp_flags & INP_RECVDSTADDR) { 1675 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1676 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1677 if (*mp) 1678 mp = &(*mp)->m_next; 1679 } 1680 #ifdef notyet 1681 /* XXX 1682 * Moving these out of udp_input() made them even more broken 1683 * than they already were. 1684 */ 1685 /* options were tossed already */ 1686 if (inp->inp_flags & INP_RECVOPTS) { 1687 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1688 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1689 if (*mp) 1690 mp = &(*mp)->m_next; 1691 } 1692 /* ip_srcroute doesn't do what we want here, need to fix */ 1693 if (inp->inp_flags & INP_RECVRETOPTS) { 1694 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1695 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1696 if (*mp) 1697 mp = &(*mp)->m_next; 1698 } 1699 #endif 1700 if (inp->inp_flags & INP_RECVIF) { 1701 struct ifnet *ifp; 1702 struct sdlbuf { 1703 struct sockaddr_dl sdl; 1704 u_char pad[32]; 1705 } sdlbuf; 1706 struct sockaddr_dl *sdp; 1707 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1708 1709 if (((ifp = m->m_pkthdr.rcvif)) 1710 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1711 sdp = (struct sockaddr_dl *)(ifnet_addrs 1712 [ifp->if_index - 1]->ifa_addr); 1713 /* 1714 * Change our mind and don't try copy. 1715 */ 1716 if ((sdp->sdl_family != AF_LINK) 1717 || (sdp->sdl_len > sizeof(sdlbuf))) { 1718 goto makedummy; 1719 } 1720 bcopy(sdp, sdl2, sdp->sdl_len); 1721 } else { 1722 makedummy: 1723 sdl2->sdl_len 1724 = offsetof(struct sockaddr_dl, sdl_data[0]); 1725 sdl2->sdl_family = AF_LINK; 1726 sdl2->sdl_index = 0; 1727 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1728 } 1729 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1730 IP_RECVIF, IPPROTO_IP); 1731 if (*mp) 1732 mp = &(*mp)->m_next; 1733 } 1734 } 1735 1736 int 1737 ip_rsvp_init(struct socket *so) 1738 { 1739 if (so->so_type != SOCK_RAW || 1740 so->so_proto->pr_protocol != IPPROTO_RSVP) 1741 return EOPNOTSUPP; 1742 1743 if (ip_rsvpd != NULL) 1744 return EADDRINUSE; 1745 1746 ip_rsvpd = so; 1747 /* 1748 * This may seem silly, but we need to be sure we don't over-increment 1749 * the RSVP counter, in case something slips up. 1750 */ 1751 if (!ip_rsvp_on) { 1752 ip_rsvp_on = 1; 1753 rsvp_on++; 1754 } 1755 1756 return 0; 1757 } 1758 1759 int 1760 ip_rsvp_done(void) 1761 { 1762 ip_rsvpd = NULL; 1763 /* 1764 * This may seem silly, but we need to be sure we don't over-decrement 1765 * the RSVP counter, in case something slips up. 1766 */ 1767 if (ip_rsvp_on) { 1768 ip_rsvp_on = 0; 1769 rsvp_on--; 1770 } 1771 return 0; 1772 } 1773