ip_input.c revision 46420
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 * $Id: ip_input.c,v 1.118 1999/05/03 23:57:29 billf Exp $ 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 45#include <stddef.h> 46 47#include <sys/param.h> 48#include <sys/systm.h> 49#include <sys/mbuf.h> 50#include <sys/malloc.h> 51#include <sys/domain.h> 52#include <sys/protosw.h> 53#include <sys/socket.h> 54#include <sys/time.h> 55#include <sys/kernel.h> 56#include <sys/syslog.h> 57#include <sys/sysctl.h> 58 59#include <net/if.h> 60#include <net/if_var.h> 61#include <net/if_dl.h> 62#include <net/route.h> 63#include <net/netisr.h> 64 65#include <netinet/in.h> 66#include <netinet/in_systm.h> 67#include <netinet/in_var.h> 68#include <netinet/ip.h> 69#include <netinet/in_pcb.h> 70#include <netinet/ip_var.h> 71#include <netinet/ip_icmp.h> 72#include <machine/in_cksum.h> 73 74#include <sys/socketvar.h> 75 76#include <netinet/ip_fw.h> 77 78#ifdef DUMMYNET 79#include <netinet/ip_dummynet.h> 80#endif 81 82int rsvp_on = 0; 83static int ip_rsvp_on; 84struct socket *ip_rsvpd; 85 86int ipforwarding = 0; 87SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 88 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 89 90static int ipsendredirects = 1; /* XXX */ 91SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 92 &ipsendredirects, 0, "Enable sending IP redirects"); 93 94int ip_defttl = IPDEFTTL; 95SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 96 &ip_defttl, 0, "Maximum TTL on IP packets"); 97 98static int ip_dosourceroute = 0; 99SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 100 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 101 102static int ip_acceptsourceroute = 0; 103SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 104 CTLFLAG_RW, &ip_acceptsourceroute, 0, 105 "Enable accepting source routed IP packets"); 106#ifdef DIAGNOSTIC 107static int ipprintfs = 0; 108#endif 109 110extern struct domain inetdomain; 111extern struct protosw inetsw[]; 112u_char ip_protox[IPPROTO_MAX]; 113static int ipqmaxlen = IFQ_MAXLEN; 114struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 115struct ifqueue ipintrq; 116SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RD, 117 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 118SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 119 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 120 121struct ipstat ipstat; 122SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RD, 123 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 124 125/* Packet reassembly stuff */ 126#define IPREASS_NHASH_LOG2 6 127#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 128#define IPREASS_HMASK (IPREASS_NHASH - 1) 129#define IPREASS_HASH(x,y) \ 130 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 131 132static struct ipq ipq[IPREASS_NHASH]; 133static int nipq = 0; /* total # of reass queues */ 134static int maxnipq; 135 136#ifdef IPCTL_DEFMTU 137SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 138 &ip_mtu, 0, "Default MTU"); 139#endif 140 141#ifdef IPSTEALTH 142static int ipstealth = 0; 143SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 144 &ipstealth, 0, ""); 145#endif 146 147 148/* Firewall hooks */ 149ip_fw_chk_t *ip_fw_chk_ptr; 150ip_fw_ctl_t *ip_fw_ctl_ptr; 151 152#ifdef DUMMYNET 153ip_dn_ctl_t *ip_dn_ctl_ptr; 154#endif 155 156#if defined(IPFILTER_LKM) || defined(IPFILTER) 157int iplattach __P((void)); 158int (*fr_checkp) __P((struct ip *, int, struct ifnet *, int, struct mbuf **)) = NULL; 159#endif 160 161 162/* 163 * We need to save the IP options in case a protocol wants to respond 164 * to an incoming packet over the same route if the packet got here 165 * using IP source routing. This allows connection establishment and 166 * maintenance when the remote end is on a network that is not known 167 * to us. 168 */ 169static int ip_nhops = 0; 170static struct ip_srcrt { 171 struct in_addr dst; /* final destination */ 172 char nop; /* one NOP to align */ 173 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 174 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 175} ip_srcrt; 176 177#ifdef IPDIVERT 178/* 179 * Shared variable between ip_input() and ip_reass() to communicate 180 * about which packets, once assembled from fragments, get diverted, 181 * and to which port. 182 */ 183static u_short frag_divert_port; 184#endif 185 186struct sockaddr_in *ip_fw_fwd_addr; 187 188static void save_rte __P((u_char *, struct in_addr)); 189static int ip_dooptions __P((struct mbuf *)); 190static void ip_forward __P((struct mbuf *, int)); 191static void ip_freef __P((struct ipq *)); 192static struct ip * 193 ip_reass __P((struct mbuf *, struct ipq *, struct ipq *)); 194static struct in_ifaddr * 195 ip_rtaddr __P((struct in_addr)); 196static void ipintr __P((void)); 197/* 198 * IP initialization: fill in IP protocol switch table. 199 * All protocols not implemented in kernel go to raw IP protocol handler. 200 */ 201void 202ip_init() 203{ 204 register struct protosw *pr; 205 register int i; 206 207 TAILQ_INIT(&in_ifaddrhead); 208 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 209 if (pr == 0) 210 panic("ip_init"); 211 for (i = 0; i < IPPROTO_MAX; i++) 212 ip_protox[i] = pr - inetsw; 213 for (pr = inetdomain.dom_protosw; 214 pr < inetdomain.dom_protoswNPROTOSW; pr++) 215 if (pr->pr_domain->dom_family == PF_INET && 216 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 217 ip_protox[pr->pr_protocol] = pr - inetsw; 218 219 for (i = 0; i < IPREASS_NHASH; i++) 220 ipq[i].next = ipq[i].prev = &ipq[i]; 221 222 maxnipq = nmbclusters/4; 223 224 ip_id = time_second & 0xffff; 225 ipintrq.ifq_maxlen = ipqmaxlen; 226#ifdef IPFILTER 227 iplattach(); 228#endif 229 230} 231 232static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 233static struct route ipforward_rt; 234 235/* 236 * Ip input routine. Checksum and byte swap header. If fragmented 237 * try to reassemble. Process options. Pass to next level. 238 */ 239void 240ip_input(struct mbuf *m) 241{ 242 struct ip *ip; 243 struct ipq *fp; 244 struct in_ifaddr *ia; 245 int i, hlen, mff; 246 u_short sum; 247#ifndef IPDIVERT /* dummy variable for the firewall code to play with */ 248 u_short ip_divert_cookie = 0 ; 249#endif 250 struct ip_fw_chain *rule = NULL ; 251 252#if defined(IPFIREWALL) && defined(DUMMYNET) 253 /* 254 * dummynet packet are prepended a vestigial mbuf with 255 * m_type = MT_DUMMYNET and m_data pointing to the matching 256 * rule. 257 */ 258 if (m->m_type == MT_DUMMYNET) { 259 rule = (struct ip_fw_chain *)(m->m_data) ; 260 m = m->m_next ; 261 ip = mtod(m, struct ip *); 262 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 263 goto iphack ; 264 } else 265 rule = NULL ; 266#endif 267 268#ifdef DIAGNOSTIC 269 if (m == NULL || (m->m_flags & M_PKTHDR) == 0) 270 panic("ip_input no HDR"); 271#endif 272 ipstat.ips_total++; 273 274 if (m->m_pkthdr.len < sizeof(struct ip)) 275 goto tooshort; 276 277 if (m->m_len < sizeof (struct ip) && 278 (m = m_pullup(m, sizeof (struct ip))) == 0) { 279 ipstat.ips_toosmall++; 280 return; 281 } 282 ip = mtod(m, struct ip *); 283 284 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 285 ipstat.ips_badvers++; 286 goto bad; 287 } 288 289 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 290 if (hlen < sizeof(struct ip)) { /* minimum header length */ 291 ipstat.ips_badhlen++; 292 goto bad; 293 } 294 if (hlen > m->m_len) { 295 if ((m = m_pullup(m, hlen)) == 0) { 296 ipstat.ips_badhlen++; 297 return; 298 } 299 ip = mtod(m, struct ip *); 300 } 301 if (hlen == sizeof(struct ip)) { 302 sum = in_cksum_hdr(ip); 303 } else { 304 sum = in_cksum(m, hlen); 305 } 306 if (sum) { 307 ipstat.ips_badsum++; 308 goto bad; 309 } 310 311 /* 312 * Convert fields to host representation. 313 */ 314 NTOHS(ip->ip_len); 315 if (ip->ip_len < hlen) { 316 ipstat.ips_badlen++; 317 goto bad; 318 } 319 NTOHS(ip->ip_id); 320 NTOHS(ip->ip_off); 321 322 /* 323 * Check that the amount of data in the buffers 324 * is as at least much as the IP header would have us expect. 325 * Trim mbufs if longer than we expect. 326 * Drop packet if shorter than we expect. 327 */ 328 if (m->m_pkthdr.len < ip->ip_len) { 329tooshort: 330 ipstat.ips_tooshort++; 331 goto bad; 332 } 333 if (m->m_pkthdr.len > ip->ip_len) { 334 if (m->m_len == m->m_pkthdr.len) { 335 m->m_len = ip->ip_len; 336 m->m_pkthdr.len = ip->ip_len; 337 } else 338 m_adj(m, ip->ip_len - m->m_pkthdr.len); 339 } 340 /* 341 * IpHack's section. 342 * Right now when no processing on packet has done 343 * and it is still fresh out of network we do our black 344 * deals with it. 345 * - Firewall: deny/allow/divert 346 * - Xlate: translate packet's addr/port (NAT). 347 * - Pipe: pass pkt through dummynet. 348 * - Wrap: fake packet's addr/port <unimpl.> 349 * - Encapsulate: put it in another IP and send out. <unimp.> 350 */ 351 352#if defined(IPFIREWALL) && defined(DUMMYNET) 353iphack: 354#endif 355#if defined(IPFILTER) || defined(IPFILTER_LKM) 356 /* 357 * Check if we want to allow this packet to be processed. 358 * Consider it to be bad if not. 359 */ 360 if (fr_checkp) { 361 struct mbuf *m1 = m; 362 363 if ((*fr_checkp)(ip, hlen, m->m_pkthdr.rcvif, 0, &m1) || !m1) 364 return; 365 ip = mtod(m = m1, struct ip *); 366 } 367#endif 368 if (ip_fw_chk_ptr) { 369#ifdef IPFIREWALL_FORWARD 370 /* 371 * If we've been forwarded from the output side, then 372 * skip the firewall a second time 373 */ 374 if (ip_fw_fwd_addr) 375 goto ours; 376#endif /* IPFIREWALL_FORWARD */ 377 i = (*ip_fw_chk_ptr)(&ip, hlen, NULL, &ip_divert_cookie, 378 &m, &rule, &ip_fw_fwd_addr); 379 /* 380 * see the comment in ip_output for the return values 381 * produced by the firewall. 382 */ 383 if (!m) /* packet discarded by firewall */ 384 return ; 385 if (i == 0 && ip_fw_fwd_addr == NULL) /* common case */ 386 goto pass ; 387#ifdef DUMMYNET 388 if (i & 0x10000) { 389 /* send packet to the appropriate pipe */ 390 dummynet_io(i&0xffff,DN_TO_IP_IN,m,NULL,NULL,0, rule); 391 return ; 392 } 393#endif 394#ifdef IPDIVERT 395 if (i > 0 && i < 0x10000) { 396 /* Divert packet */ 397 frag_divert_port = i & 0xffff ; 398 goto ours; 399 } 400#endif 401#ifdef IPFIREWALL_FORWARD 402 if (i == 0 && ip_fw_fwd_addr != NULL) 403 goto pass ; 404#endif 405 /* 406 * if we get here, the packet must be dropped 407 */ 408 m_freem(m); 409 return; 410 } 411pass: 412 413 /* 414 * Process options and, if not destined for us, 415 * ship it on. ip_dooptions returns 1 when an 416 * error was detected (causing an icmp message 417 * to be sent and the original packet to be freed). 418 */ 419 ip_nhops = 0; /* for source routed packets */ 420 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 421#ifdef IPFIREWALL_FORWARD 422 ip_fw_fwd_addr = NULL; 423#endif 424 return; 425 } 426 427 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 428 * matter if it is destined to another node, or whether it is 429 * a multicast one, RSVP wants it! and prevents it from being forwarded 430 * anywhere else. Also checks if the rsvp daemon is running before 431 * grabbing the packet. 432 */ 433 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 434 goto ours; 435 436 /* 437 * Check our list of addresses, to see if the packet is for us. 438 * If we don't have any addresses, assume any unicast packet 439 * we receive might be for us (and let the upper layers deal 440 * with it). 441 */ 442 if (TAILQ_EMPTY(&in_ifaddrhead) && 443 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 444 goto ours; 445 446 for (ia = TAILQ_FIRST(&in_ifaddrhead); ia; 447 ia = TAILQ_NEXT(ia, ia_link)) { 448#define satosin(sa) ((struct sockaddr_in *)(sa)) 449 450#ifdef BOOTP_COMPAT 451 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 452 goto ours; 453#endif 454#ifdef IPFIREWALL_FORWARD 455 /* 456 * If the addr to forward to is one of ours, we pretend to 457 * be the destination for this packet. 458 */ 459 if (ip_fw_fwd_addr == NULL) { 460 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 461 goto ours; 462 } else if (IA_SIN(ia)->sin_addr.s_addr == 463 ip_fw_fwd_addr->sin_addr.s_addr) 464 goto ours; 465#else 466 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 467 goto ours; 468#endif 469 if (ia->ia_ifp && ia->ia_ifp->if_flags & IFF_BROADCAST) { 470 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 471 ip->ip_dst.s_addr) 472 goto ours; 473 if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr) 474 goto ours; 475 } 476 } 477 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 478 struct in_multi *inm; 479 if (ip_mrouter) { 480 /* 481 * If we are acting as a multicast router, all 482 * incoming multicast packets are passed to the 483 * kernel-level multicast forwarding function. 484 * The packet is returned (relatively) intact; if 485 * ip_mforward() returns a non-zero value, the packet 486 * must be discarded, else it may be accepted below. 487 * 488 * (The IP ident field is put in the same byte order 489 * as expected when ip_mforward() is called from 490 * ip_output().) 491 */ 492 ip->ip_id = htons(ip->ip_id); 493 if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 494 ipstat.ips_cantforward++; 495 m_freem(m); 496 return; 497 } 498 ip->ip_id = ntohs(ip->ip_id); 499 500 /* 501 * The process-level routing demon needs to receive 502 * all multicast IGMP packets, whether or not this 503 * host belongs to their destination groups. 504 */ 505 if (ip->ip_p == IPPROTO_IGMP) 506 goto ours; 507 ipstat.ips_forward++; 508 } 509 /* 510 * See if we belong to the destination multicast group on the 511 * arrival interface. 512 */ 513 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 514 if (inm == NULL) { 515 ipstat.ips_notmember++; 516 m_freem(m); 517 return; 518 } 519 goto ours; 520 } 521 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 522 goto ours; 523 if (ip->ip_dst.s_addr == INADDR_ANY) 524 goto ours; 525 526 /* 527 * Not for us; forward if possible and desirable. 528 */ 529 if (ipforwarding == 0) { 530 ipstat.ips_cantforward++; 531 m_freem(m); 532 } else 533 ip_forward(m, 0); 534#ifdef IPFIREWALL_FORWARD 535 ip_fw_fwd_addr = NULL; 536#endif 537 return; 538 539ours: 540 541 /* 542 * If offset or IP_MF are set, must reassemble. 543 * Otherwise, nothing need be done. 544 * (We could look in the reassembly queue to see 545 * if the packet was previously fragmented, 546 * but it's not worth the time; just let them time out.) 547 */ 548 if (ip->ip_off & (IP_MF | IP_OFFMASK | IP_RF)) { 549 if (m->m_flags & M_EXT) { /* XXX */ 550 if ((m = m_pullup(m, hlen)) == 0) { 551 ipstat.ips_toosmall++; 552#ifdef IPDIVERT 553 frag_divert_port = 0; 554 ip_divert_cookie = 0; 555#endif 556#ifdef IPFIREWALL_FORWARD 557 ip_fw_fwd_addr = NULL; 558#endif 559 return; 560 } 561 ip = mtod(m, struct ip *); 562 } 563 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 564 /* 565 * Look for queue of fragments 566 * of this datagram. 567 */ 568 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 569 if (ip->ip_id == fp->ipq_id && 570 ip->ip_src.s_addr == fp->ipq_src.s_addr && 571 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 572 ip->ip_p == fp->ipq_p) 573 goto found; 574 575 fp = 0; 576 577 /* check if there's a place for the new queue */ 578 if (nipq > maxnipq) { 579 /* 580 * drop something from the tail of the current queue 581 * before proceeding further 582 */ 583 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 584 for (i = 0; i < IPREASS_NHASH; i++) { 585 if (ipq[i].prev != &ipq[i]) { 586 ip_freef(ipq[i].prev); 587 break; 588 } 589 } 590 } else 591 ip_freef(ipq[sum].prev); 592 } 593found: 594 /* 595 * Adjust ip_len to not reflect header, 596 * set ip_mff if more fragments are expected, 597 * convert offset of this to bytes. 598 */ 599 ip->ip_len -= hlen; 600 mff = (ip->ip_off & IP_MF) != 0; 601 if (mff) { 602 /* 603 * Make sure that fragments have a data length 604 * that's a non-zero multiple of 8 bytes. 605 */ 606 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 607 ipstat.ips_toosmall++; /* XXX */ 608 goto bad; 609 } 610 m->m_flags |= M_FRAG; 611 } 612 ip->ip_off <<= 3; 613 614 /* 615 * If datagram marked as having more fragments 616 * or if this is not the first fragment, 617 * attempt reassembly; if it succeeds, proceed. 618 */ 619 if (mff || ip->ip_off) { 620 ipstat.ips_fragments++; 621 m->m_pkthdr.header = ip; 622 ip = ip_reass(m, fp, &ipq[sum]); 623 if (ip == 0) { 624#ifdef IPFIREWALL_FORWARD 625 ip_fw_fwd_addr = NULL; 626#endif 627 return; 628 } 629 /* Get the length of the reassembled packets header */ 630 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 631 ipstat.ips_reassembled++; 632 m = dtom(ip); 633#ifdef IPDIVERT 634 if (frag_divert_port) { 635 ip->ip_len += hlen; 636 HTONS(ip->ip_len); 637 HTONS(ip->ip_off); 638 HTONS(ip->ip_id); 639 ip->ip_sum = 0; 640 ip->ip_sum = in_cksum_hdr(ip); 641 NTOHS(ip->ip_id); 642 NTOHS(ip->ip_off); 643 NTOHS(ip->ip_len); 644 ip->ip_len -= hlen; 645 } 646#endif 647 } else 648 if (fp) 649 ip_freef(fp); 650 } else 651 ip->ip_len -= hlen; 652 653#ifdef IPDIVERT 654 /* 655 * Divert reassembled packets to the divert protocol if required 656 * If divert port is null then cookie should be too, 657 * so we shouldn't need to clear them here. Assume ip_divert does so. 658 */ 659 if (frag_divert_port) { 660 ipstat.ips_delivered++; 661 ip_divert_port = frag_divert_port; 662 frag_divert_port = 0; 663 (*inetsw[ip_protox[IPPROTO_DIVERT]].pr_input)(m, hlen); 664 return; 665 } 666 667 /* Don't let packets divert themselves */ 668 if (ip->ip_p == IPPROTO_DIVERT) { 669 ipstat.ips_noproto++; 670 goto bad; 671 } 672 673#endif 674 675 /* 676 * Switch out to protocol's input routine. 677 */ 678 ipstat.ips_delivered++; 679 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 680#ifdef IPFIREWALL_FORWARD 681 ip_fw_fwd_addr = NULL; /* tcp needed it */ 682#endif 683 return; 684bad: 685#ifdef IPFIREWALL_FORWARD 686 ip_fw_fwd_addr = NULL; 687#endif 688 m_freem(m); 689} 690 691/* 692 * IP software interrupt routine - to go away sometime soon 693 */ 694static void 695ipintr(void) 696{ 697 int s; 698 struct mbuf *m; 699 700 while(1) { 701 s = splimp(); 702 IF_DEQUEUE(&ipintrq, m); 703 splx(s); 704 if (m == 0) 705 return; 706 ip_input(m); 707 } 708} 709 710NETISR_SET(NETISR_IP, ipintr); 711 712/* 713 * Take incoming datagram fragment and try to 714 * reassemble it into whole datagram. If a chain for 715 * reassembly of this datagram already exists, then it 716 * is given as fp; otherwise have to make a chain. 717 */ 718static struct ip * 719ip_reass(m, fp, where) 720 register struct mbuf *m; 721 register struct ipq *fp; 722 struct ipq *where; 723{ 724 struct ip *ip = mtod(m, struct ip *); 725 register struct mbuf *p = 0, *q, *nq; 726 struct mbuf *t; 727 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 728 int i, next; 729 730 /* 731 * Presence of header sizes in mbufs 732 * would confuse code below. 733 */ 734 m->m_data += hlen; 735 m->m_len -= hlen; 736 737 /* 738 * If first fragment to arrive, create a reassembly queue. 739 */ 740 if (fp == 0) { 741 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 742 goto dropfrag; 743 fp = mtod(t, struct ipq *); 744 insque(fp, where); 745 nipq++; 746 fp->ipq_ttl = IPFRAGTTL; 747 fp->ipq_p = ip->ip_p; 748 fp->ipq_id = ip->ip_id; 749 fp->ipq_src = ip->ip_src; 750 fp->ipq_dst = ip->ip_dst; 751 fp->ipq_frags = m; 752 m->m_nextpkt = NULL; 753#ifdef IPDIVERT 754 fp->ipq_divert = 0; 755 fp->ipq_div_cookie = 0; 756#endif 757 goto inserted; 758 } 759 760#define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 761 762 /* 763 * Find a segment which begins after this one does. 764 */ 765 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 766 if (GETIP(q)->ip_off > ip->ip_off) 767 break; 768 769 /* 770 * If there is a preceding segment, it may provide some of 771 * our data already. If so, drop the data from the incoming 772 * segment. If it provides all of our data, drop us, otherwise 773 * stick new segment in the proper place. 774 */ 775 if (p) { 776 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 777 if (i > 0) { 778 if (i >= ip->ip_len) 779 goto dropfrag; 780 m_adj(dtom(ip), i); 781 ip->ip_off += i; 782 ip->ip_len -= i; 783 } 784 m->m_nextpkt = p->m_nextpkt; 785 p->m_nextpkt = m; 786 } else { 787 m->m_nextpkt = fp->ipq_frags; 788 fp->ipq_frags = m; 789 } 790 791 /* 792 * While we overlap succeeding segments trim them or, 793 * if they are completely covered, dequeue them. 794 */ 795 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 796 q = nq) { 797 i = (ip->ip_off + ip->ip_len) - 798 GETIP(q)->ip_off; 799 if (i < GETIP(q)->ip_len) { 800 GETIP(q)->ip_len -= i; 801 GETIP(q)->ip_off += i; 802 m_adj(q, i); 803 break; 804 } 805 nq = q->m_nextpkt; 806 m->m_nextpkt = nq; 807 m_freem(q); 808 } 809 810inserted: 811 812#ifdef IPDIVERT 813 /* 814 * Any fragment diverting causes the whole packet to divert 815 */ 816 if (frag_divert_port) { 817 fp->ipq_divert = frag_divert_port; 818 fp->ipq_div_cookie = ip_divert_cookie; 819 } 820 frag_divert_port = 0; 821 ip_divert_cookie = 0; 822#endif 823 824 /* 825 * Check for complete reassembly. 826 */ 827 next = 0; 828 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 829 if (GETIP(q)->ip_off != next) 830 return (0); 831 next += GETIP(q)->ip_len; 832 } 833 /* Make sure the last packet didn't have the IP_MF flag */ 834 if (p->m_flags & M_FRAG) 835 return (0); 836 837 /* 838 * Reassembly is complete. Make sure the packet is a sane size. 839 */ 840 q = fp->ipq_frags; 841 ip = GETIP(q); 842 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 843 ipstat.ips_toolong++; 844 ip_freef(fp); 845 return (0); 846 } 847 848 /* 849 * Concatenate fragments. 850 */ 851 m = q; 852 t = m->m_next; 853 m->m_next = 0; 854 m_cat(m, t); 855 nq = q->m_nextpkt; 856 q->m_nextpkt = 0; 857 for (q = nq; q != NULL; q = nq) { 858 nq = q->m_nextpkt; 859 q->m_nextpkt = NULL; 860 m_cat(m, q); 861 } 862 863#ifdef IPDIVERT 864 /* 865 * extract divert port for packet, if any 866 */ 867 frag_divert_port = fp->ipq_divert; 868 ip_divert_cookie = fp->ipq_div_cookie; 869#endif 870 871 /* 872 * Create header for new ip packet by 873 * modifying header of first packet; 874 * dequeue and discard fragment reassembly header. 875 * Make header visible. 876 */ 877 ip->ip_len = next; 878 ip->ip_src = fp->ipq_src; 879 ip->ip_dst = fp->ipq_dst; 880 remque(fp); 881 nipq--; 882 (void) m_free(dtom(fp)); 883 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 884 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 885 /* some debugging cruft by sklower, below, will go away soon */ 886 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 887 register int plen = 0; 888 for (t = m; m; m = m->m_next) 889 plen += m->m_len; 890 t->m_pkthdr.len = plen; 891 } 892 return (ip); 893 894dropfrag: 895#ifdef IPDIVERT 896 frag_divert_port = 0; 897 ip_divert_cookie = 0; 898#endif 899 ipstat.ips_fragdropped++; 900 m_freem(m); 901 return (0); 902 903#undef GETIP 904} 905 906/* 907 * Free a fragment reassembly header and all 908 * associated datagrams. 909 */ 910static void 911ip_freef(fp) 912 struct ipq *fp; 913{ 914 register struct mbuf *q; 915 916 while (fp->ipq_frags) { 917 q = fp->ipq_frags; 918 fp->ipq_frags = q->m_nextpkt; 919 m_freem(q); 920 } 921 remque(fp); 922 (void) m_free(dtom(fp)); 923 nipq--; 924} 925 926/* 927 * IP timer processing; 928 * if a timer expires on a reassembly 929 * queue, discard it. 930 */ 931void 932ip_slowtimo() 933{ 934 register struct ipq *fp; 935 int s = splnet(); 936 int i; 937 938 for (i = 0; i < IPREASS_NHASH; i++) { 939 fp = ipq[i].next; 940 if (fp == 0) 941 continue; 942 while (fp != &ipq[i]) { 943 --fp->ipq_ttl; 944 fp = fp->next; 945 if (fp->prev->ipq_ttl == 0) { 946 ipstat.ips_fragtimeout++; 947 ip_freef(fp->prev); 948 } 949 } 950 } 951 ipflow_slowtimo(); 952 splx(s); 953} 954 955/* 956 * Drain off all datagram fragments. 957 */ 958void 959ip_drain() 960{ 961 int i; 962 963 for (i = 0; i < IPREASS_NHASH; i++) { 964 while (ipq[i].next != &ipq[i]) { 965 ipstat.ips_fragdropped++; 966 ip_freef(ipq[i].next); 967 } 968 } 969 in_rtqdrain(); 970} 971 972/* 973 * Do option processing on a datagram, 974 * possibly discarding it if bad options are encountered, 975 * or forwarding it if source-routed. 976 * Returns 1 if packet has been forwarded/freed, 977 * 0 if the packet should be processed further. 978 */ 979static int 980ip_dooptions(m) 981 struct mbuf *m; 982{ 983 register struct ip *ip = mtod(m, struct ip *); 984 register u_char *cp; 985 register struct ip_timestamp *ipt; 986 register struct in_ifaddr *ia; 987 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 988 struct in_addr *sin, dst; 989 n_time ntime; 990 991 dst = ip->ip_dst; 992 cp = (u_char *)(ip + 1); 993 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 994 for (; cnt > 0; cnt -= optlen, cp += optlen) { 995 opt = cp[IPOPT_OPTVAL]; 996 if (opt == IPOPT_EOL) 997 break; 998 if (opt == IPOPT_NOP) 999 optlen = 1; 1000 else { 1001 optlen = cp[IPOPT_OLEN]; 1002 if (optlen <= 0 || optlen > cnt) { 1003 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1004 goto bad; 1005 } 1006 } 1007 switch (opt) { 1008 1009 default: 1010 break; 1011 1012 /* 1013 * Source routing with record. 1014 * Find interface with current destination address. 1015 * If none on this machine then drop if strictly routed, 1016 * or do nothing if loosely routed. 1017 * Record interface address and bring up next address 1018 * component. If strictly routed make sure next 1019 * address is on directly accessible net. 1020 */ 1021 case IPOPT_LSRR: 1022 case IPOPT_SSRR: 1023 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1024 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1025 goto bad; 1026 } 1027 ipaddr.sin_addr = ip->ip_dst; 1028 ia = (struct in_ifaddr *) 1029 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1030 if (ia == 0) { 1031 if (opt == IPOPT_SSRR) { 1032 type = ICMP_UNREACH; 1033 code = ICMP_UNREACH_SRCFAIL; 1034 goto bad; 1035 } 1036 if (!ip_dosourceroute) 1037 goto nosourcerouting; 1038 /* 1039 * Loose routing, and not at next destination 1040 * yet; nothing to do except forward. 1041 */ 1042 break; 1043 } 1044 off--; /* 0 origin */ 1045 if (off > optlen - sizeof(struct in_addr)) { 1046 /* 1047 * End of source route. Should be for us. 1048 */ 1049 if (!ip_acceptsourceroute) 1050 goto nosourcerouting; 1051 save_rte(cp, ip->ip_src); 1052 break; 1053 } 1054 1055 if (!ip_dosourceroute) { 1056 if (ipforwarding) { 1057 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1058 /* 1059 * Acting as a router, so generate ICMP 1060 */ 1061nosourcerouting: 1062 strcpy(buf, inet_ntoa(ip->ip_dst)); 1063 log(LOG_WARNING, 1064 "attempted source route from %s to %s\n", 1065 inet_ntoa(ip->ip_src), buf); 1066 type = ICMP_UNREACH; 1067 code = ICMP_UNREACH_SRCFAIL; 1068 goto bad; 1069 } else { 1070 /* 1071 * Not acting as a router, so silently drop. 1072 */ 1073 ipstat.ips_cantforward++; 1074 m_freem(m); 1075 return (1); 1076 } 1077 } 1078 1079 /* 1080 * locate outgoing interface 1081 */ 1082 (void)memcpy(&ipaddr.sin_addr, cp + off, 1083 sizeof(ipaddr.sin_addr)); 1084 1085 if (opt == IPOPT_SSRR) { 1086#define INA struct in_ifaddr * 1087#define SA struct sockaddr * 1088 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1089 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1090 } else 1091 ia = ip_rtaddr(ipaddr.sin_addr); 1092 if (ia == 0) { 1093 type = ICMP_UNREACH; 1094 code = ICMP_UNREACH_SRCFAIL; 1095 goto bad; 1096 } 1097 ip->ip_dst = ipaddr.sin_addr; 1098 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1099 sizeof(struct in_addr)); 1100 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1101 /* 1102 * Let ip_intr's mcast routing check handle mcast pkts 1103 */ 1104 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1105 break; 1106 1107 case IPOPT_RR: 1108 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1109 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1110 goto bad; 1111 } 1112 /* 1113 * If no space remains, ignore. 1114 */ 1115 off--; /* 0 origin */ 1116 if (off > optlen - sizeof(struct in_addr)) 1117 break; 1118 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1119 sizeof(ipaddr.sin_addr)); 1120 /* 1121 * locate outgoing interface; if we're the destination, 1122 * use the incoming interface (should be same). 1123 */ 1124 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1125 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1126 type = ICMP_UNREACH; 1127 code = ICMP_UNREACH_HOST; 1128 goto bad; 1129 } 1130 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1131 sizeof(struct in_addr)); 1132 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1133 break; 1134 1135 case IPOPT_TS: 1136 code = cp - (u_char *)ip; 1137 ipt = (struct ip_timestamp *)cp; 1138 if (ipt->ipt_len < 5) 1139 goto bad; 1140 if (ipt->ipt_ptr > ipt->ipt_len - sizeof(int32_t)) { 1141 if (++ipt->ipt_oflw == 0) 1142 goto bad; 1143 break; 1144 } 1145 sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); 1146 switch (ipt->ipt_flg) { 1147 1148 case IPOPT_TS_TSONLY: 1149 break; 1150 1151 case IPOPT_TS_TSANDADDR: 1152 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1153 sizeof(struct in_addr) > ipt->ipt_len) 1154 goto bad; 1155 ipaddr.sin_addr = dst; 1156 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1157 m->m_pkthdr.rcvif); 1158 if (ia == 0) 1159 continue; 1160 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1161 sizeof(struct in_addr)); 1162 ipt->ipt_ptr += sizeof(struct in_addr); 1163 break; 1164 1165 case IPOPT_TS_PRESPEC: 1166 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1167 sizeof(struct in_addr) > ipt->ipt_len) 1168 goto bad; 1169 (void)memcpy(&ipaddr.sin_addr, sin, 1170 sizeof(struct in_addr)); 1171 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1172 continue; 1173 ipt->ipt_ptr += sizeof(struct in_addr); 1174 break; 1175 1176 default: 1177 goto bad; 1178 } 1179 ntime = iptime(); 1180 (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime, 1181 sizeof(n_time)); 1182 ipt->ipt_ptr += sizeof(n_time); 1183 } 1184 } 1185 if (forward && ipforwarding) { 1186 ip_forward(m, 1); 1187 return (1); 1188 } 1189 return (0); 1190bad: 1191 ip->ip_len -= IP_VHL_HL(ip->ip_vhl) << 2; /* XXX icmp_error adds in hdr length */ 1192 icmp_error(m, type, code, 0, 0); 1193 ipstat.ips_badoptions++; 1194 return (1); 1195} 1196 1197/* 1198 * Given address of next destination (final or next hop), 1199 * return internet address info of interface to be used to get there. 1200 */ 1201static struct in_ifaddr * 1202ip_rtaddr(dst) 1203 struct in_addr dst; 1204{ 1205 register struct sockaddr_in *sin; 1206 1207 sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; 1208 1209 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 1210 if (ipforward_rt.ro_rt) { 1211 RTFREE(ipforward_rt.ro_rt); 1212 ipforward_rt.ro_rt = 0; 1213 } 1214 sin->sin_family = AF_INET; 1215 sin->sin_len = sizeof(*sin); 1216 sin->sin_addr = dst; 1217 1218 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1219 } 1220 if (ipforward_rt.ro_rt == 0) 1221 return ((struct in_ifaddr *)0); 1222 return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); 1223} 1224 1225/* 1226 * Save incoming source route for use in replies, 1227 * to be picked up later by ip_srcroute if the receiver is interested. 1228 */ 1229void 1230save_rte(option, dst) 1231 u_char *option; 1232 struct in_addr dst; 1233{ 1234 unsigned olen; 1235 1236 olen = option[IPOPT_OLEN]; 1237#ifdef DIAGNOSTIC 1238 if (ipprintfs) 1239 printf("save_rte: olen %d\n", olen); 1240#endif 1241 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1242 return; 1243 bcopy(option, ip_srcrt.srcopt, olen); 1244 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1245 ip_srcrt.dst = dst; 1246} 1247 1248/* 1249 * Retrieve incoming source route for use in replies, 1250 * in the same form used by setsockopt. 1251 * The first hop is placed before the options, will be removed later. 1252 */ 1253struct mbuf * 1254ip_srcroute() 1255{ 1256 register struct in_addr *p, *q; 1257 register struct mbuf *m; 1258 1259 if (ip_nhops == 0) 1260 return ((struct mbuf *)0); 1261 m = m_get(M_DONTWAIT, MT_HEADER); 1262 if (m == 0) 1263 return ((struct mbuf *)0); 1264 1265#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1266 1267 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1268 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1269 OPTSIZ; 1270#ifdef DIAGNOSTIC 1271 if (ipprintfs) 1272 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1273#endif 1274 1275 /* 1276 * First save first hop for return route 1277 */ 1278 p = &ip_srcrt.route[ip_nhops - 1]; 1279 *(mtod(m, struct in_addr *)) = *p--; 1280#ifdef DIAGNOSTIC 1281 if (ipprintfs) 1282 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1283#endif 1284 1285 /* 1286 * Copy option fields and padding (nop) to mbuf. 1287 */ 1288 ip_srcrt.nop = IPOPT_NOP; 1289 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1290 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1291 &ip_srcrt.nop, OPTSIZ); 1292 q = (struct in_addr *)(mtod(m, caddr_t) + 1293 sizeof(struct in_addr) + OPTSIZ); 1294#undef OPTSIZ 1295 /* 1296 * Record return path as an IP source route, 1297 * reversing the path (pointers are now aligned). 1298 */ 1299 while (p >= ip_srcrt.route) { 1300#ifdef DIAGNOSTIC 1301 if (ipprintfs) 1302 printf(" %lx", (u_long)ntohl(q->s_addr)); 1303#endif 1304 *q++ = *p--; 1305 } 1306 /* 1307 * Last hop goes to final destination. 1308 */ 1309 *q = ip_srcrt.dst; 1310#ifdef DIAGNOSTIC 1311 if (ipprintfs) 1312 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1313#endif 1314 return (m); 1315} 1316 1317/* 1318 * Strip out IP options, at higher 1319 * level protocol in the kernel. 1320 * Second argument is buffer to which options 1321 * will be moved, and return value is their length. 1322 * XXX should be deleted; last arg currently ignored. 1323 */ 1324void 1325ip_stripoptions(m, mopt) 1326 register struct mbuf *m; 1327 struct mbuf *mopt; 1328{ 1329 register int i; 1330 struct ip *ip = mtod(m, struct ip *); 1331 register caddr_t opts; 1332 int olen; 1333 1334 olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1335 opts = (caddr_t)(ip + 1); 1336 i = m->m_len - (sizeof (struct ip) + olen); 1337 bcopy(opts + olen, opts, (unsigned)i); 1338 m->m_len -= olen; 1339 if (m->m_flags & M_PKTHDR) 1340 m->m_pkthdr.len -= olen; 1341 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1342} 1343 1344u_char inetctlerrmap[PRC_NCMDS] = { 1345 0, 0, 0, 0, 1346 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1347 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1348 EMSGSIZE, EHOSTUNREACH, 0, 0, 1349 0, 0, 0, 0, 1350 ENOPROTOOPT 1351}; 1352 1353/* 1354 * Forward a packet. If some error occurs return the sender 1355 * an icmp packet. Note we can't always generate a meaningful 1356 * icmp message because icmp doesn't have a large enough repertoire 1357 * of codes and types. 1358 * 1359 * If not forwarding, just drop the packet. This could be confusing 1360 * if ipforwarding was zero but some routing protocol was advancing 1361 * us as a gateway to somewhere. However, we must let the routing 1362 * protocol deal with that. 1363 * 1364 * The srcrt parameter indicates whether the packet is being forwarded 1365 * via a source route. 1366 */ 1367static void 1368ip_forward(m, srcrt) 1369 struct mbuf *m; 1370 int srcrt; 1371{ 1372 register struct ip *ip = mtod(m, struct ip *); 1373 register struct sockaddr_in *sin; 1374 register struct rtentry *rt; 1375 int error, type = 0, code = 0; 1376 struct mbuf *mcopy; 1377 n_long dest; 1378 struct ifnet *destifp; 1379 1380 dest = 0; 1381#ifdef DIAGNOSTIC 1382 if (ipprintfs) 1383 printf("forward: src %lx dst %lx ttl %x\n", 1384 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1385 ip->ip_ttl); 1386#endif 1387 1388 1389 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1390 ipstat.ips_cantforward++; 1391 m_freem(m); 1392 return; 1393 } 1394 HTONS(ip->ip_id); 1395#ifdef IPSTEALTH 1396 if (!ipstealth) { 1397#endif 1398 if (ip->ip_ttl <= IPTTLDEC) { 1399 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1400 dest, 0); 1401 return; 1402 } 1403 ip->ip_ttl -= IPTTLDEC; 1404#ifdef IPSTEALTH 1405 } 1406#endif 1407 1408 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1409 if ((rt = ipforward_rt.ro_rt) == 0 || 1410 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1411 if (ipforward_rt.ro_rt) { 1412 RTFREE(ipforward_rt.ro_rt); 1413 ipforward_rt.ro_rt = 0; 1414 } 1415 sin->sin_family = AF_INET; 1416 sin->sin_len = sizeof(*sin); 1417 sin->sin_addr = ip->ip_dst; 1418 1419 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1420 if (ipforward_rt.ro_rt == 0) { 1421 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1422 return; 1423 } 1424 rt = ipforward_rt.ro_rt; 1425 } 1426 1427 /* 1428 * Save at most 64 bytes of the packet in case 1429 * we need to generate an ICMP message to the src. 1430 */ 1431 mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); 1432 1433 /* 1434 * If forwarding packet using same interface that it came in on, 1435 * perhaps should send a redirect to sender to shortcut a hop. 1436 * Only send redirect if source is sending directly to us, 1437 * and if packet was not source routed (or has any options). 1438 * Also, don't send redirect if forwarding using a default route 1439 * or a route modified by a redirect. 1440 */ 1441#define satosin(sa) ((struct sockaddr_in *)(sa)) 1442 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1443 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1444 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1445 ipsendredirects && !srcrt) { 1446#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1447 u_long src = ntohl(ip->ip_src.s_addr); 1448 1449 if (RTA(rt) && 1450 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1451 if (rt->rt_flags & RTF_GATEWAY) 1452 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1453 else 1454 dest = ip->ip_dst.s_addr; 1455 /* Router requirements says to only send host redirects */ 1456 type = ICMP_REDIRECT; 1457 code = ICMP_REDIRECT_HOST; 1458#ifdef DIAGNOSTIC 1459 if (ipprintfs) 1460 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1461#endif 1462 } 1463 } 1464 1465 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1466 IP_FORWARDING, 0); 1467 if (error) 1468 ipstat.ips_cantforward++; 1469 else { 1470 ipstat.ips_forward++; 1471 if (type) 1472 ipstat.ips_redirectsent++; 1473 else { 1474 if (mcopy) { 1475 ipflow_create(&ipforward_rt, mcopy); 1476 m_freem(mcopy); 1477 } 1478 return; 1479 } 1480 } 1481 if (mcopy == NULL) 1482 return; 1483 destifp = NULL; 1484 1485 switch (error) { 1486 1487 case 0: /* forwarded, but need redirect */ 1488 /* type, code set above */ 1489 break; 1490 1491 case ENETUNREACH: /* shouldn't happen, checked above */ 1492 case EHOSTUNREACH: 1493 case ENETDOWN: 1494 case EHOSTDOWN: 1495 default: 1496 type = ICMP_UNREACH; 1497 code = ICMP_UNREACH_HOST; 1498 break; 1499 1500 case EMSGSIZE: 1501 type = ICMP_UNREACH; 1502 code = ICMP_UNREACH_NEEDFRAG; 1503 if (ipforward_rt.ro_rt) 1504 destifp = ipforward_rt.ro_rt->rt_ifp; 1505 ipstat.ips_cantfrag++; 1506 break; 1507 1508 case ENOBUFS: 1509 type = ICMP_SOURCEQUENCH; 1510 code = 0; 1511 break; 1512 } 1513 icmp_error(mcopy, type, code, dest, destifp); 1514} 1515 1516void 1517ip_savecontrol(inp, mp, ip, m) 1518 register struct inpcb *inp; 1519 register struct mbuf **mp; 1520 register struct ip *ip; 1521 register struct mbuf *m; 1522{ 1523 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1524 struct timeval tv; 1525 1526 microtime(&tv); 1527 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1528 SCM_TIMESTAMP, SOL_SOCKET); 1529 if (*mp) 1530 mp = &(*mp)->m_next; 1531 } 1532 if (inp->inp_flags & INP_RECVDSTADDR) { 1533 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1534 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1535 if (*mp) 1536 mp = &(*mp)->m_next; 1537 } 1538#ifdef notyet 1539 /* XXX 1540 * Moving these out of udp_input() made them even more broken 1541 * than they already were. 1542 */ 1543 /* options were tossed already */ 1544 if (inp->inp_flags & INP_RECVOPTS) { 1545 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1546 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1547 if (*mp) 1548 mp = &(*mp)->m_next; 1549 } 1550 /* ip_srcroute doesn't do what we want here, need to fix */ 1551 if (inp->inp_flags & INP_RECVRETOPTS) { 1552 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1553 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1554 if (*mp) 1555 mp = &(*mp)->m_next; 1556 } 1557#endif 1558 if (inp->inp_flags & INP_RECVIF) { 1559 struct ifnet *ifp; 1560 struct sdlbuf { 1561 struct sockaddr_dl sdl; 1562 u_char pad[32]; 1563 } sdlbuf; 1564 struct sockaddr_dl *sdp; 1565 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1566 1567 if (((ifp = m->m_pkthdr.rcvif)) 1568 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1569 sdp = (struct sockaddr_dl *)(ifnet_addrs 1570 [ifp->if_index - 1]->ifa_addr); 1571 /* 1572 * Change our mind and don't try copy. 1573 */ 1574 if ((sdp->sdl_family != AF_LINK) 1575 || (sdp->sdl_len > sizeof(sdlbuf))) { 1576 goto makedummy; 1577 } 1578 bcopy(sdp, sdl2, sdp->sdl_len); 1579 } else { 1580makedummy: 1581 sdl2->sdl_len 1582 = offsetof(struct sockaddr_dl, sdl_data[0]); 1583 sdl2->sdl_family = AF_LINK; 1584 sdl2->sdl_index = 0; 1585 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1586 } 1587 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1588 IP_RECVIF, IPPROTO_IP); 1589 if (*mp) 1590 mp = &(*mp)->m_next; 1591 } 1592} 1593 1594int 1595ip_rsvp_init(struct socket *so) 1596{ 1597 if (so->so_type != SOCK_RAW || 1598 so->so_proto->pr_protocol != IPPROTO_RSVP) 1599 return EOPNOTSUPP; 1600 1601 if (ip_rsvpd != NULL) 1602 return EADDRINUSE; 1603 1604 ip_rsvpd = so; 1605 /* 1606 * This may seem silly, but we need to be sure we don't over-increment 1607 * the RSVP counter, in case something slips up. 1608 */ 1609 if (!ip_rsvp_on) { 1610 ip_rsvp_on = 1; 1611 rsvp_on++; 1612 } 1613 1614 return 0; 1615} 1616 1617int 1618ip_rsvp_done(void) 1619{ 1620 ip_rsvpd = NULL; 1621 /* 1622 * This may seem silly, but we need to be sure we don't over-decrement 1623 * the RSVP counter, in case something slips up. 1624 */ 1625 if (ip_rsvp_on) { 1626 ip_rsvp_on = 0; 1627 rsvp_on--; 1628 } 1629 return 0; 1630} 1631