ip_input.c revision 37412
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 1.92 1998/07/06 03:20:16 julian Exp $ 35 * $ANA: ip_input.c,v 1.5 1996/09/18 14:34:59 wollman Exp $ 36 */ 37 38#define _IP_VHL 39 40#include "opt_bootp.h" 41#include "opt_ipfw.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/domain.h> 51#include <sys/protosw.h> 52#include <sys/socket.h> 53#include <sys/time.h> 54#include <sys/kernel.h> 55#include <sys/syslog.h> 56#include <sys/sysctl.h> 57 58#include <net/if.h> 59#include <net/if_var.h> 60#include <net/if_dl.h> 61#include <net/route.h> 62#include <net/netisr.h> 63 64#include <netinet/in.h> 65#include <netinet/in_systm.h> 66#include <netinet/in_var.h> 67#include <netinet/ip.h> 68#include <netinet/in_pcb.h> 69#include <netinet/ip_var.h> 70#include <netinet/ip_icmp.h> 71#include <machine/in_cksum.h> 72 73#include <sys/socketvar.h> 74 75#ifdef IPFIREWALL 76#include <netinet/ip_fw.h> 77#endif 78 79int rsvp_on = 0; 80static int ip_rsvp_on; 81struct socket *ip_rsvpd; 82 83int ipforwarding = 0; 84SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 85 &ipforwarding, 0, ""); 86 87static int ipsendredirects = 1; /* XXX */ 88SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 89 &ipsendredirects, 0, ""); 90 91int ip_defttl = IPDEFTTL; 92SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 93 &ip_defttl, 0, ""); 94 95static int ip_dosourceroute = 0; 96SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 97 &ip_dosourceroute, 0, ""); 98 99static int ip_acceptsourceroute = 0; 100SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 101 CTLFLAG_RW, &ip_acceptsourceroute, 0, ""); 102#ifdef DIAGNOSTIC 103static int ipprintfs = 0; 104#endif 105 106extern struct domain inetdomain; 107extern struct protosw inetsw[]; 108u_char ip_protox[IPPROTO_MAX]; 109static int ipqmaxlen = IFQ_MAXLEN; 110struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 111struct ifqueue ipintrq; 112SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RD, 113 &ipintrq.ifq_maxlen, 0, ""); 114SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 115 &ipintrq.ifq_drops, 0, ""); 116 117struct ipstat ipstat; 118SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RD, 119 &ipstat, ipstat, ""); 120 121/* Packet reassembly stuff */ 122#define IPREASS_NHASH_LOG2 6 123#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 124#define IPREASS_HMASK (IPREASS_NHASH - 1) 125#define IPREASS_HASH(x,y) \ 126 ((((x) & 0xF | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 127 128static struct ipq ipq[IPREASS_NHASH]; 129static int nipq = 0; /* total # of reass queues */ 130static int maxnipq; 131 132#ifdef IPCTL_DEFMTU 133SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 134 &ip_mtu, 0, ""); 135#endif 136 137#if !defined(COMPAT_IPFW) || COMPAT_IPFW == 1 138#undef COMPAT_IPFW 139#define COMPAT_IPFW 1 140#else 141#undef COMPAT_IPFW 142#endif 143 144#ifdef COMPAT_IPFW 145/* Firewall hooks */ 146ip_fw_chk_t *ip_fw_chk_ptr; 147ip_fw_ctl_t *ip_fw_ctl_ptr; 148 149/* IP Network Address Translation (NAT) hooks */ 150ip_nat_t *ip_nat_ptr; 151ip_nat_ctl_t *ip_nat_ctl_ptr; 152#endif 153 154#if defined(IPFILTER_LKM) || defined(IPFILTER) 155int iplattach __P((void)); 156int (*fr_checkp) __P((struct ip *, int, struct ifnet *, int, struct mbuf **)) = NULL; 157#endif 158 159 160/* 161 * We need to save the IP options in case a protocol wants to respond 162 * to an incoming packet over the same route if the packet got here 163 * using IP source routing. This allows connection establishment and 164 * maintenance when the remote end is on a network that is not known 165 * to us. 166 */ 167static int ip_nhops = 0; 168static struct ip_srcrt { 169 struct in_addr dst; /* final destination */ 170 char nop; /* one NOP to align */ 171 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 172 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 173} ip_srcrt; 174 175#ifdef IPDIVERT 176/* 177 * Shared variable between ip_input() and ip_reass() to communicate 178 * about which packets, once assembled from fragments, get diverted, 179 * and to which port. 180 */ 181static u_short frag_divert_port; 182#endif 183 184struct sockaddr_in *ip_fw_fwd_addr; 185 186static void save_rte __P((u_char *, struct in_addr)); 187static void ip_deq __P((struct ipasfrag *)); 188static int ip_dooptions __P((struct mbuf *)); 189static void ip_enq __P((struct ipasfrag *, struct ipasfrag *)); 190static void ip_forward __P((struct mbuf *, int)); 191static void ip_freef __P((struct ipq *)); 192static struct ip * 193 ip_reass __P((struct ipasfrag *, 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 IPFIREWALL 227 ip_fw_init(); 228#endif 229#ifdef IPNAT 230 ip_nat_init(); 231#endif 232#ifdef IPFILTER 233 iplattach(); 234#endif 235 236} 237 238static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 239static struct route ipforward_rt; 240 241/* 242 * Ip input routine. Checksum and byte swap header. If fragmented 243 * try to reassemble. Process options. Pass to next level. 244 */ 245void 246ip_input(struct mbuf *m) 247{ 248 struct ip *ip; 249 struct ipq *fp; 250 struct in_ifaddr *ia; 251 int i, hlen; 252 u_short sum; 253 254#ifdef DIAGNOSTIC 255 if (m == NULL || (m->m_flags & M_PKTHDR) == 0) 256 panic("ip_input no HDR"); 257#endif 258 /* 259 * If no IP addresses have been set yet but the interfaces 260 * are receiving, can't do anything with incoming packets yet. 261 * XXX This is broken! We should be able to receive broadcasts 262 * and multicasts even without any local addresses configured. 263 */ 264 if (TAILQ_EMPTY(&in_ifaddrhead)) 265 goto bad; 266 ipstat.ips_total++; 267 268 if (m->m_pkthdr.len < sizeof(struct ip)) 269 goto tooshort; 270 271 if (m->m_len < sizeof (struct ip) && 272 (m = m_pullup(m, sizeof (struct ip))) == 0) { 273 ipstat.ips_toosmall++; 274 return; 275 } 276 ip = mtod(m, struct ip *); 277 278 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 279 ipstat.ips_badvers++; 280 goto bad; 281 } 282 283 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 284 if (hlen < sizeof(struct ip)) { /* minimum header length */ 285 ipstat.ips_badhlen++; 286 goto bad; 287 } 288 if (hlen > m->m_len) { 289 if ((m = m_pullup(m, hlen)) == 0) { 290 ipstat.ips_badhlen++; 291 return; 292 } 293 ip = mtod(m, struct ip *); 294 } 295 if (hlen == sizeof(struct ip)) { 296 sum = in_cksum_hdr(ip); 297 } else { 298 sum = in_cksum(m, hlen); 299 } 300 if (sum) { 301 ipstat.ips_badsum++; 302 goto bad; 303 } 304 305 /* 306 * Convert fields to host representation. 307 */ 308 NTOHS(ip->ip_len); 309 if (ip->ip_len < hlen) { 310 ipstat.ips_badlen++; 311 goto bad; 312 } 313 NTOHS(ip->ip_id); 314 NTOHS(ip->ip_off); 315 316 /* 317 * Check that the amount of data in the buffers 318 * is as at least much as the IP header would have us expect. 319 * Trim mbufs if longer than we expect. 320 * Drop packet if shorter than we expect. 321 */ 322 if (m->m_pkthdr.len < ip->ip_len) { 323tooshort: 324 ipstat.ips_tooshort++; 325 goto bad; 326 } 327 if (m->m_pkthdr.len > ip->ip_len) { 328 if (m->m_len == m->m_pkthdr.len) { 329 m->m_len = ip->ip_len; 330 m->m_pkthdr.len = ip->ip_len; 331 } else 332 m_adj(m, ip->ip_len - m->m_pkthdr.len); 333 } 334 /* 335 * IpHack's section. 336 * Right now when no processing on packet has done 337 * and it is still fresh out of network we do our black 338 * deals with it. 339 * - Firewall: deny/allow/divert 340 * - Xlate: translate packet's addr/port (NAT). 341 * - Wrap: fake packet's addr/port <unimpl.> 342 * - Encapsulate: put it in another IP and send out. <unimp.> 343 */ 344#if defined(IPFILTER) || defined(IPFILTER_LKM) 345 /* 346 * Check if we want to allow this packet to be processed. 347 * Consider it to be bad if not. 348 */ 349 if (fr_checkp) { 350 struct mbuf *m1 = m; 351 352 if ((*fr_checkp)(ip, hlen, m->m_pkthdr.rcvif, 0, &m1) || !m1) 353 return; 354 ip = mtod(m = m1, struct ip *); 355 } 356#endif 357#ifdef COMPAT_IPFW 358 if (ip_fw_chk_ptr) { 359 u_int16_t port; 360 361#ifdef IPFIREWALL_FORWARD 362 /* 363 * If we've been forwarded from the output side, then 364 * skip the firewall a second time 365 */ 366 if (ip_fw_fwd_addr) 367 goto ours; 368#endif /* IPFIREWALL_FORWARD */ 369#ifdef IPDIVERT 370 port = (*ip_fw_chk_ptr)(&ip, hlen, NULL, &ip_divert_cookie, 371 &m, &ip_fw_fwd_addr); 372 if (port) { 373 /* Divert packet */ 374 frag_divert_port = port; 375 goto ours; 376 } 377#else /* !DIVERT */ 378 /* 379 * If ipfw says divert, we have to just drop packet */ 380 * Use port as a dummy argument. 381 */ 382 port = 0; 383 if ((*ip_fw_chk_ptr)(&ip, hlen, NULL, &port, 384 &m, &ip_fw_fwd_addr)) { 385 m_freem(m); 386 m = NULL; 387 } 388#endif /* !DIVERT */ 389 if (!m) 390 return; 391 } 392 393 if (ip_nat_ptr && !(*ip_nat_ptr)(&ip, &m, m->m_pkthdr.rcvif, IP_NAT_IN)) 394 return; 395#endif /* !COMPAT_IPFW */ 396 397 /* 398 * Process options and, if not destined for us, 399 * ship it on. ip_dooptions returns 1 when an 400 * error was detected (causing an icmp message 401 * to be sent and the original packet to be freed). 402 */ 403 ip_nhops = 0; /* for source routed packets */ 404 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 405 return; 406 407 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 408 * matter if it is destined to another node, or whether it is 409 * a multicast one, RSVP wants it! and prevents it from being forwarded 410 * anywhere else. Also checks if the rsvp daemon is running before 411 * grabbing the packet. 412 */ 413 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 414 goto ours; 415 416 /* 417 * Check our list of addresses, to see if the packet is for us. 418 */ 419 for (ia = TAILQ_FIRST(&in_ifaddrhead); ia; 420 ia = TAILQ_NEXT(ia, ia_link)) { 421#define satosin(sa) ((struct sockaddr_in *)(sa)) 422 423 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 424 goto ours; 425#ifdef BOOTP_COMPAT 426 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 427 goto ours; 428#endif 429#ifdef IPFIREWALL_FORWARD 430 /* 431 * If the addr to forward to is one of ours, we pretend to 432 * be the destination for this packet. 433 */ 434 if (ip_fw_fwd_addr != NULL && 435 IA_SIN(ia)->sin_addr.s_addr == 436 ip_fw_fwd_addr->sin_addr.s_addr) 437 goto ours; 438#endif 439 if (ia->ia_ifp && ia->ia_ifp->if_flags & IFF_BROADCAST) { 440 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 441 ip->ip_dst.s_addr) 442 goto ours; 443 if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr) 444 goto ours; 445 } 446 } 447 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 448 struct in_multi *inm; 449 if (ip_mrouter) { 450 /* 451 * If we are acting as a multicast router, all 452 * incoming multicast packets are passed to the 453 * kernel-level multicast forwarding function. 454 * The packet is returned (relatively) intact; if 455 * ip_mforward() returns a non-zero value, the packet 456 * must be discarded, else it may be accepted below. 457 * 458 * (The IP ident field is put in the same byte order 459 * as expected when ip_mforward() is called from 460 * ip_output().) 461 */ 462 ip->ip_id = htons(ip->ip_id); 463 if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 464 ipstat.ips_cantforward++; 465 m_freem(m); 466 return; 467 } 468 ip->ip_id = ntohs(ip->ip_id); 469 470 /* 471 * The process-level routing demon needs to receive 472 * all multicast IGMP packets, whether or not this 473 * host belongs to their destination groups. 474 */ 475 if (ip->ip_p == IPPROTO_IGMP) 476 goto ours; 477 ipstat.ips_forward++; 478 } 479 /* 480 * See if we belong to the destination multicast group on the 481 * arrival interface. 482 */ 483 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 484 if (inm == NULL) { 485 ipstat.ips_notmember++; 486 m_freem(m); 487 return; 488 } 489 goto ours; 490 } 491 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 492 goto ours; 493 if (ip->ip_dst.s_addr == INADDR_ANY) 494 goto ours; 495 496 /* 497 * Not for us; forward if possible and desirable. 498 */ 499 if (ipforwarding == 0) { 500 ipstat.ips_cantforward++; 501 m_freem(m); 502 } else 503 ip_forward(m, 0); 504 return; 505 506ours: 507 508 /* 509 * If offset or IP_MF are set, must reassemble. 510 * Otherwise, nothing need be done. 511 * (We could look in the reassembly queue to see 512 * if the packet was previously fragmented, 513 * but it's not worth the time; just let them time out.) 514 */ 515 if (ip->ip_off & (IP_MF | IP_OFFMASK | IP_RF)) { 516 if (m->m_flags & M_EXT) { /* XXX */ 517 if ((m = m_pullup(m, sizeof (struct ip))) == 0) { 518 ipstat.ips_toosmall++; 519#ifdef IPDIVERT 520 frag_divert_port = 0; 521 ip_divert_cookie = 0; 522#endif 523 return; 524 } 525 ip = mtod(m, struct ip *); 526 } 527 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 528 /* 529 * Look for queue of fragments 530 * of this datagram. 531 */ 532 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 533 if (ip->ip_id == fp->ipq_id && 534 ip->ip_src.s_addr == fp->ipq_src.s_addr && 535 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 536 ip->ip_p == fp->ipq_p) 537 goto found; 538 539 fp = 0; 540 541 /* check if there's a place for the new queue */ 542 if (nipq > maxnipq) { 543 /* 544 * drop something from the tail of the current queue 545 * before proceeding further 546 */ 547 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 548 for (i = 0; i < IPREASS_NHASH; i++) { 549 if (ipq[i].prev != &ipq[i]) { 550 ip_freef(ipq[i].prev); 551 break; 552 } 553 } 554 } else 555 ip_freef(ipq[sum].prev); 556 } 557found: 558 /* 559 * Adjust ip_len to not reflect header, 560 * set ip_mff if more fragments are expected, 561 * convert offset of this to bytes. 562 */ 563 ip->ip_len -= hlen; 564 ((struct ipasfrag *)ip)->ipf_mff &= ~1; 565 if (ip->ip_off & IP_MF) 566 ((struct ipasfrag *)ip)->ipf_mff |= 1; 567 ip->ip_off <<= 3; 568 569 /* 570 * If datagram marked as having more fragments 571 * or if this is not the first fragment, 572 * attempt reassembly; if it succeeds, proceed. 573 */ 574 if (((struct ipasfrag *)ip)->ipf_mff & 1 || ip->ip_off) { 575 ipstat.ips_fragments++; 576 ip = ip_reass((struct ipasfrag *)ip, fp, &ipq[sum]); 577 if (ip == 0) { 578#ifdef IPFIREWALL_FORWARD 579 ip_fw_fwd_addr = NULL; 580#endif 581 return; 582 } 583 /* Get the length of the reassembled packets header */ 584 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 585 ipstat.ips_reassembled++; 586 m = dtom(ip); 587#ifdef IPDIVERT 588 if (frag_divert_port) { 589 ip->ip_len += hlen; 590 HTONS(ip->ip_len); 591 HTONS(ip->ip_off); 592 HTONS(ip->ip_id); 593 ip->ip_sum = 0; 594 ip->ip_sum = in_cksum_hdr(ip); 595 NTOHS(ip->ip_id); 596 NTOHS(ip->ip_off); 597 NTOHS(ip->ip_len); 598 ip->ip_len -= hlen; 599 } 600#endif 601 } else 602 if (fp) 603 ip_freef(fp); 604 } else 605 ip->ip_len -= hlen; 606 607#ifdef IPDIVERT 608 /* 609 * Divert reassembled packets to the divert protocol if required 610 */ 611 if (frag_divert_port) { 612 ipstat.ips_delivered++; 613 ip_divert_port = frag_divert_port; 614 frag_divert_port = 0; 615 (*inetsw[ip_protox[IPPROTO_DIVERT]].pr_input)(m, hlen); 616 return; 617 } 618 619 /* Don't let packets divert themselves */ 620 if (ip->ip_p == IPPROTO_DIVERT) { 621 ipstat.ips_noproto++; 622 goto bad; 623 } 624 625#endif 626 627 /* 628 * Switch out to protocol's input routine. 629 */ 630 ipstat.ips_delivered++; 631 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 632#ifdef IPFIREWALL_FORWARD 633 ip_fw_fwd_addr = NULL; /* tcp needed it */ 634#endif 635 return; 636bad: 637#ifdef IPFIREWALL_FORWARD 638 ip_fw_fwd_addr = NULL; 639#endif 640 m_freem(m); 641} 642 643/* 644 * IP software interrupt routine - to go away sometime soon 645 */ 646static void 647ipintr(void) 648{ 649 int s; 650 struct mbuf *m; 651 652 while(1) { 653 s = splimp(); 654 IF_DEQUEUE(&ipintrq, m); 655 splx(s); 656 if (m == 0) 657 return; 658 ip_input(m); 659 } 660} 661 662NETISR_SET(NETISR_IP, ipintr); 663 664/* 665 * Take incoming datagram fragment and try to 666 * reassemble it into whole datagram. If a chain for 667 * reassembly of this datagram already exists, then it 668 * is given as fp; otherwise have to make a chain. 669 */ 670static struct ip * 671ip_reass(ip, fp, where) 672 register struct ipasfrag *ip; 673 register struct ipq *fp; 674 struct ipq *where; 675{ 676 register struct mbuf *m = dtom(ip); 677 register struct ipasfrag *q; 678 struct mbuf *t; 679 int hlen = ip->ip_hl << 2; 680 int i, next; 681 682 /* 683 * Presence of header sizes in mbufs 684 * would confuse code below. 685 */ 686 m->m_data += hlen; 687 m->m_len -= hlen; 688 689 /* 690 * If first fragment to arrive, create a reassembly queue. 691 */ 692 if (fp == 0) { 693 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 694 goto dropfrag; 695 fp = mtod(t, struct ipq *); 696 insque(fp, where); 697 nipq++; 698 fp->ipq_ttl = IPFRAGTTL; 699 fp->ipq_p = ip->ip_p; 700 fp->ipq_id = ip->ip_id; 701 fp->ipq_next = fp->ipq_prev = (struct ipasfrag *)fp; 702 fp->ipq_src = ((struct ip *)ip)->ip_src; 703 fp->ipq_dst = ((struct ip *)ip)->ip_dst; 704#ifdef IPDIVERT 705 fp->ipq_divert = 0; 706 fp->ipq_div_cookie = 0; 707#endif 708 q = (struct ipasfrag *)fp; 709 goto insert; 710 } 711 712 /* 713 * Find a segment which begins after this one does. 714 */ 715 for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) 716 if (q->ip_off > ip->ip_off) 717 break; 718 719 /* 720 * If there is a preceding segment, it may provide some of 721 * our data already. If so, drop the data from the incoming 722 * segment. If it provides all of our data, drop us. 723 */ 724 if (q->ipf_prev != (struct ipasfrag *)fp) { 725 i = q->ipf_prev->ip_off + q->ipf_prev->ip_len - ip->ip_off; 726 if (i > 0) { 727 if (i >= ip->ip_len) 728 goto dropfrag; 729 m_adj(dtom(ip), i); 730 ip->ip_off += i; 731 ip->ip_len -= i; 732 } 733 } 734 735 /* 736 * While we overlap succeeding segments trim them or, 737 * if they are completely covered, dequeue them. 738 */ 739 while (q != (struct ipasfrag *)fp && ip->ip_off + ip->ip_len > q->ip_off) { 740 struct mbuf *m0; 741 742 i = (ip->ip_off + ip->ip_len) - q->ip_off; 743 if (i < q->ip_len) { 744 q->ip_len -= i; 745 q->ip_off += i; 746 m_adj(dtom(q), i); 747 break; 748 } 749 m0 = dtom(q); 750 q = q->ipf_next; 751 ip_deq(q->ipf_prev); 752 m_freem(m0); 753 } 754 755insert: 756 757#ifdef IPDIVERT 758 /* 759 * Any fragment diverting causes the whole packet to divert 760 */ 761 if (frag_divert_port != 0) { 762 fp->ipq_divert = frag_divert_port; 763 fp->ipq_div_cookie = ip_divert_cookie; 764 } 765 frag_divert_port = 0; 766 ip_divert_cookie = 0; 767#endif 768 769 /* 770 * Stick new segment in its place; 771 * check for complete reassembly. 772 */ 773 ip_enq(ip, q->ipf_prev); 774 next = 0; 775 for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) { 776 if (q->ip_off != next) 777 return (0); 778 next += q->ip_len; 779 } 780 if (q->ipf_prev->ipf_mff & 1) 781 return (0); 782 783 /* 784 * Reassembly is complete. Make sure the packet is a sane size. 785 */ 786 if (next + (IP_VHL_HL(((struct ip *)fp->ipq_next)->ip_vhl) << 2) 787 > IP_MAXPACKET) { 788 ipstat.ips_toolong++; 789 ip_freef(fp); 790 return (0); 791 } 792 793 /* 794 * Concatenate fragments. 795 */ 796 q = fp->ipq_next; 797 m = dtom(q); 798 t = m->m_next; 799 m->m_next = 0; 800 m_cat(m, t); 801 q = q->ipf_next; 802 while (q != (struct ipasfrag *)fp) { 803 t = dtom(q); 804 q = q->ipf_next; 805 m_cat(m, t); 806 } 807 808#ifdef IPDIVERT 809 /* 810 * extract divert port for packet, if any 811 */ 812 frag_divert_port = fp->ipq_divert; 813 ip_divert_cookie = fp->ipq_div_cookie; 814#endif 815 816 /* 817 * Create header for new ip packet by 818 * modifying header of first packet; 819 * dequeue and discard fragment reassembly header. 820 * Make header visible. 821 */ 822 ip = fp->ipq_next; 823 ip->ip_len = next; 824 ip->ipf_mff &= ~1; 825 ((struct ip *)ip)->ip_src = fp->ipq_src; 826 ((struct ip *)ip)->ip_dst = fp->ipq_dst; 827 remque(fp); 828 nipq--; 829 (void) m_free(dtom(fp)); 830 m = dtom(ip); 831 m->m_len += (ip->ip_hl << 2); 832 m->m_data -= (ip->ip_hl << 2); 833 /* some debugging cruft by sklower, below, will go away soon */ 834 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 835 register int plen = 0; 836 for (t = m; m; m = m->m_next) 837 plen += m->m_len; 838 t->m_pkthdr.len = plen; 839 } 840 return ((struct ip *)ip); 841 842dropfrag: 843 ipstat.ips_fragdropped++; 844 m_freem(m); 845 return (0); 846} 847 848/* 849 * Free a fragment reassembly header and all 850 * associated datagrams. 851 */ 852static void 853ip_freef(fp) 854 struct ipq *fp; 855{ 856 register struct ipasfrag *q, *p; 857 858 for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = p) { 859 p = q->ipf_next; 860 ip_deq(q); 861 m_freem(dtom(q)); 862 } 863 remque(fp); 864 (void) m_free(dtom(fp)); 865 nipq--; 866} 867 868/* 869 * Put an ip fragment on a reassembly chain. 870 * Like insque, but pointers in middle of structure. 871 */ 872static void 873ip_enq(p, prev) 874 register struct ipasfrag *p, *prev; 875{ 876 877 p->ipf_prev = prev; 878 p->ipf_next = prev->ipf_next; 879 prev->ipf_next->ipf_prev = p; 880 prev->ipf_next = p; 881} 882 883/* 884 * To ip_enq as remque is to insque. 885 */ 886static void 887ip_deq(p) 888 register struct ipasfrag *p; 889{ 890 891 p->ipf_prev->ipf_next = p->ipf_next; 892 p->ipf_next->ipf_prev = p->ipf_prev; 893} 894 895/* 896 * IP timer processing; 897 * if a timer expires on a reassembly 898 * queue, discard it. 899 */ 900void 901ip_slowtimo() 902{ 903 register struct ipq *fp; 904 int s = splnet(); 905 int i; 906 907 for (i = 0; i < IPREASS_NHASH; i++) { 908 fp = ipq[i].next; 909 if (fp == 0) 910 continue; 911 while (fp != &ipq[i]) { 912 --fp->ipq_ttl; 913 fp = fp->next; 914 if (fp->prev->ipq_ttl == 0) { 915 ipstat.ips_fragtimeout++; 916 ip_freef(fp->prev); 917 } 918 } 919 } 920 ipflow_slowtimo(); 921 splx(s); 922} 923 924/* 925 * Drain off all datagram fragments. 926 */ 927void 928ip_drain() 929{ 930 int i; 931 932 for (i = 0; i < IPREASS_NHASH; i++) { 933 while (ipq[i].next != &ipq[i]) { 934 ipstat.ips_fragdropped++; 935 ip_freef(ipq[i].next); 936 } 937 } 938 in_rtqdrain(); 939} 940 941/* 942 * Do option processing on a datagram, 943 * possibly discarding it if bad options are encountered, 944 * or forwarding it if source-routed. 945 * Returns 1 if packet has been forwarded/freed, 946 * 0 if the packet should be processed further. 947 */ 948static int 949ip_dooptions(m) 950 struct mbuf *m; 951{ 952 register struct ip *ip = mtod(m, struct ip *); 953 register u_char *cp; 954 register struct ip_timestamp *ipt; 955 register struct in_ifaddr *ia; 956 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 957 struct in_addr *sin, dst; 958 n_time ntime; 959 960 dst = ip->ip_dst; 961 cp = (u_char *)(ip + 1); 962 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 963 for (; cnt > 0; cnt -= optlen, cp += optlen) { 964 opt = cp[IPOPT_OPTVAL]; 965 if (opt == IPOPT_EOL) 966 break; 967 if (opt == IPOPT_NOP) 968 optlen = 1; 969 else { 970 optlen = cp[IPOPT_OLEN]; 971 if (optlen <= 0 || optlen > cnt) { 972 code = &cp[IPOPT_OLEN] - (u_char *)ip; 973 goto bad; 974 } 975 } 976 switch (opt) { 977 978 default: 979 break; 980 981 /* 982 * Source routing with record. 983 * Find interface with current destination address. 984 * If none on this machine then drop if strictly routed, 985 * or do nothing if loosely routed. 986 * Record interface address and bring up next address 987 * component. If strictly routed make sure next 988 * address is on directly accessible net. 989 */ 990 case IPOPT_LSRR: 991 case IPOPT_SSRR: 992 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 993 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 994 goto bad; 995 } 996 ipaddr.sin_addr = ip->ip_dst; 997 ia = (struct in_ifaddr *) 998 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 999 if (ia == 0) { 1000 if (opt == IPOPT_SSRR) { 1001 type = ICMP_UNREACH; 1002 code = ICMP_UNREACH_SRCFAIL; 1003 goto bad; 1004 } 1005 if (!ip_dosourceroute) 1006 goto nosourcerouting; 1007 /* 1008 * Loose routing, and not at next destination 1009 * yet; nothing to do except forward. 1010 */ 1011 break; 1012 } 1013 off--; /* 0 origin */ 1014 if (off > optlen - sizeof(struct in_addr)) { 1015 /* 1016 * End of source route. Should be for us. 1017 */ 1018 if (!ip_acceptsourceroute) 1019 goto nosourcerouting; 1020 save_rte(cp, ip->ip_src); 1021 break; 1022 } 1023 1024 if (!ip_dosourceroute) { 1025 char buf[4*sizeof "123"]; 1026 1027nosourcerouting: 1028 strcpy(buf, inet_ntoa(ip->ip_dst)); 1029 log(LOG_WARNING, 1030 "attempted source route from %s to %s\n", 1031 inet_ntoa(ip->ip_src), buf); 1032 type = ICMP_UNREACH; 1033 code = ICMP_UNREACH_SRCFAIL; 1034 goto bad; 1035 } 1036 1037 /* 1038 * locate outgoing interface 1039 */ 1040 (void)memcpy(&ipaddr.sin_addr, cp + off, 1041 sizeof(ipaddr.sin_addr)); 1042 1043 if (opt == IPOPT_SSRR) { 1044#define INA struct in_ifaddr * 1045#define SA struct sockaddr * 1046 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1047 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1048 } else 1049 ia = ip_rtaddr(ipaddr.sin_addr); 1050 if (ia == 0) { 1051 type = ICMP_UNREACH; 1052 code = ICMP_UNREACH_SRCFAIL; 1053 goto bad; 1054 } 1055 ip->ip_dst = ipaddr.sin_addr; 1056 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1057 sizeof(struct in_addr)); 1058 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1059 /* 1060 * Let ip_intr's mcast routing check handle mcast pkts 1061 */ 1062 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1063 break; 1064 1065 case IPOPT_RR: 1066 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1067 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1068 goto bad; 1069 } 1070 /* 1071 * If no space remains, ignore. 1072 */ 1073 off--; /* 0 origin */ 1074 if (off > optlen - sizeof(struct in_addr)) 1075 break; 1076 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1077 sizeof(ipaddr.sin_addr)); 1078 /* 1079 * locate outgoing interface; if we're the destination, 1080 * use the incoming interface (should be same). 1081 */ 1082 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1083 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1084 type = ICMP_UNREACH; 1085 code = ICMP_UNREACH_HOST; 1086 goto bad; 1087 } 1088 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1089 sizeof(struct in_addr)); 1090 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1091 break; 1092 1093 case IPOPT_TS: 1094 code = cp - (u_char *)ip; 1095 ipt = (struct ip_timestamp *)cp; 1096 if (ipt->ipt_len < 5) 1097 goto bad; 1098 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (long)) { 1099 if (++ipt->ipt_oflw == 0) 1100 goto bad; 1101 break; 1102 } 1103 sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); 1104 switch (ipt->ipt_flg) { 1105 1106 case IPOPT_TS_TSONLY: 1107 break; 1108 1109 case IPOPT_TS_TSANDADDR: 1110 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1111 sizeof(struct in_addr) > ipt->ipt_len) 1112 goto bad; 1113 ipaddr.sin_addr = dst; 1114 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1115 m->m_pkthdr.rcvif); 1116 if (ia == 0) 1117 continue; 1118 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1119 sizeof(struct in_addr)); 1120 ipt->ipt_ptr += sizeof(struct in_addr); 1121 break; 1122 1123 case IPOPT_TS_PRESPEC: 1124 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1125 sizeof(struct in_addr) > ipt->ipt_len) 1126 goto bad; 1127 (void)memcpy(&ipaddr.sin_addr, sin, 1128 sizeof(struct in_addr)); 1129 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1130 continue; 1131 ipt->ipt_ptr += sizeof(struct in_addr); 1132 break; 1133 1134 default: 1135 goto bad; 1136 } 1137 ntime = iptime(); 1138 (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime, 1139 sizeof(n_time)); 1140 ipt->ipt_ptr += sizeof(n_time); 1141 } 1142 } 1143 if (forward && ipforwarding) { 1144 ip_forward(m, 1); 1145 return (1); 1146 } 1147 return (0); 1148bad: 1149 ip->ip_len -= IP_VHL_HL(ip->ip_vhl) << 2; /* XXX icmp_error adds in hdr length */ 1150 icmp_error(m, type, code, 0, 0); 1151 ipstat.ips_badoptions++; 1152 return (1); 1153} 1154 1155/* 1156 * Given address of next destination (final or next hop), 1157 * return internet address info of interface to be used to get there. 1158 */ 1159static struct in_ifaddr * 1160ip_rtaddr(dst) 1161 struct in_addr dst; 1162{ 1163 register struct sockaddr_in *sin; 1164 1165 sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; 1166 1167 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 1168 if (ipforward_rt.ro_rt) { 1169 RTFREE(ipforward_rt.ro_rt); 1170 ipforward_rt.ro_rt = 0; 1171 } 1172 sin->sin_family = AF_INET; 1173 sin->sin_len = sizeof(*sin); 1174 sin->sin_addr = dst; 1175 1176 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1177 } 1178 if (ipforward_rt.ro_rt == 0) 1179 return ((struct in_ifaddr *)0); 1180 return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); 1181} 1182 1183/* 1184 * Save incoming source route for use in replies, 1185 * to be picked up later by ip_srcroute if the receiver is interested. 1186 */ 1187void 1188save_rte(option, dst) 1189 u_char *option; 1190 struct in_addr dst; 1191{ 1192 unsigned olen; 1193 1194 olen = option[IPOPT_OLEN]; 1195#ifdef DIAGNOSTIC 1196 if (ipprintfs) 1197 printf("save_rte: olen %d\n", olen); 1198#endif 1199 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1200 return; 1201 bcopy(option, ip_srcrt.srcopt, olen); 1202 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1203 ip_srcrt.dst = dst; 1204} 1205 1206/* 1207 * Retrieve incoming source route for use in replies, 1208 * in the same form used by setsockopt. 1209 * The first hop is placed before the options, will be removed later. 1210 */ 1211struct mbuf * 1212ip_srcroute() 1213{ 1214 register struct in_addr *p, *q; 1215 register struct mbuf *m; 1216 1217 if (ip_nhops == 0) 1218 return ((struct mbuf *)0); 1219 m = m_get(M_DONTWAIT, MT_SOOPTS); 1220 if (m == 0) 1221 return ((struct mbuf *)0); 1222 1223#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1224 1225 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1226 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1227 OPTSIZ; 1228#ifdef DIAGNOSTIC 1229 if (ipprintfs) 1230 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1231#endif 1232 1233 /* 1234 * First save first hop for return route 1235 */ 1236 p = &ip_srcrt.route[ip_nhops - 1]; 1237 *(mtod(m, struct in_addr *)) = *p--; 1238#ifdef DIAGNOSTIC 1239 if (ipprintfs) 1240 printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr)); 1241#endif 1242 1243 /* 1244 * Copy option fields and padding (nop) to mbuf. 1245 */ 1246 ip_srcrt.nop = IPOPT_NOP; 1247 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1248 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1249 &ip_srcrt.nop, OPTSIZ); 1250 q = (struct in_addr *)(mtod(m, caddr_t) + 1251 sizeof(struct in_addr) + OPTSIZ); 1252#undef OPTSIZ 1253 /* 1254 * Record return path as an IP source route, 1255 * reversing the path (pointers are now aligned). 1256 */ 1257 while (p >= ip_srcrt.route) { 1258#ifdef DIAGNOSTIC 1259 if (ipprintfs) 1260 printf(" %lx", ntohl(q->s_addr)); 1261#endif 1262 *q++ = *p--; 1263 } 1264 /* 1265 * Last hop goes to final destination. 1266 */ 1267 *q = ip_srcrt.dst; 1268#ifdef DIAGNOSTIC 1269 if (ipprintfs) 1270 printf(" %lx\n", ntohl(q->s_addr)); 1271#endif 1272 return (m); 1273} 1274 1275/* 1276 * Strip out IP options, at higher 1277 * level protocol in the kernel. 1278 * Second argument is buffer to which options 1279 * will be moved, and return value is their length. 1280 * XXX should be deleted; last arg currently ignored. 1281 */ 1282void 1283ip_stripoptions(m, mopt) 1284 register struct mbuf *m; 1285 struct mbuf *mopt; 1286{ 1287 register int i; 1288 struct ip *ip = mtod(m, struct ip *); 1289 register caddr_t opts; 1290 int olen; 1291 1292 olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1293 opts = (caddr_t)(ip + 1); 1294 i = m->m_len - (sizeof (struct ip) + olen); 1295 bcopy(opts + olen, opts, (unsigned)i); 1296 m->m_len -= olen; 1297 if (m->m_flags & M_PKTHDR) 1298 m->m_pkthdr.len -= olen; 1299 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1300} 1301 1302u_char inetctlerrmap[PRC_NCMDS] = { 1303 0, 0, 0, 0, 1304 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1305 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1306 EMSGSIZE, EHOSTUNREACH, 0, 0, 1307 0, 0, 0, 0, 1308 ENOPROTOOPT 1309}; 1310 1311/* 1312 * Forward a packet. If some error occurs return the sender 1313 * an icmp packet. Note we can't always generate a meaningful 1314 * icmp message because icmp doesn't have a large enough repertoire 1315 * of codes and types. 1316 * 1317 * If not forwarding, just drop the packet. This could be confusing 1318 * if ipforwarding was zero but some routing protocol was advancing 1319 * us as a gateway to somewhere. However, we must let the routing 1320 * protocol deal with that. 1321 * 1322 * The srcrt parameter indicates whether the packet is being forwarded 1323 * via a source route. 1324 */ 1325static void 1326ip_forward(m, srcrt) 1327 struct mbuf *m; 1328 int srcrt; 1329{ 1330 register struct ip *ip = mtod(m, struct ip *); 1331 register struct sockaddr_in *sin; 1332 register struct rtentry *rt; 1333 int error, type = 0, code = 0; 1334 struct mbuf *mcopy; 1335 n_long dest; 1336 struct ifnet *destifp; 1337 1338 dest = 0; 1339#ifdef DIAGNOSTIC 1340 if (ipprintfs) 1341 printf("forward: src %lx dst %lx ttl %x\n", 1342 ip->ip_src.s_addr, ip->ip_dst.s_addr, ip->ip_ttl); 1343#endif 1344 1345 1346 if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) { 1347 ipstat.ips_cantforward++; 1348 m_freem(m); 1349 return; 1350 } 1351 HTONS(ip->ip_id); 1352 if (ip->ip_ttl <= IPTTLDEC) { 1353 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1354 return; 1355 } 1356 ip->ip_ttl -= IPTTLDEC; 1357 1358 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1359 if ((rt = ipforward_rt.ro_rt) == 0 || 1360 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1361 if (ipforward_rt.ro_rt) { 1362 RTFREE(ipforward_rt.ro_rt); 1363 ipforward_rt.ro_rt = 0; 1364 } 1365 sin->sin_family = AF_INET; 1366 sin->sin_len = sizeof(*sin); 1367 sin->sin_addr = ip->ip_dst; 1368 1369 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1370 if (ipforward_rt.ro_rt == 0) { 1371 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1372 return; 1373 } 1374 rt = ipforward_rt.ro_rt; 1375 } 1376 1377 /* 1378 * Save at most 64 bytes of the packet in case 1379 * we need to generate an ICMP message to the src. 1380 */ 1381 mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); 1382 1383 /* 1384 * If forwarding packet using same interface that it came in on, 1385 * perhaps should send a redirect to sender to shortcut a hop. 1386 * Only send redirect if source is sending directly to us, 1387 * and if packet was not source routed (or has any options). 1388 * Also, don't send redirect if forwarding using a default route 1389 * or a route modified by a redirect. 1390 */ 1391#define satosin(sa) ((struct sockaddr_in *)(sa)) 1392 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1393 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1394 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1395 ipsendredirects && !srcrt) { 1396#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1397 u_long src = ntohl(ip->ip_src.s_addr); 1398 1399 if (RTA(rt) && 1400 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1401 if (rt->rt_flags & RTF_GATEWAY) 1402 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1403 else 1404 dest = ip->ip_dst.s_addr; 1405 /* Router requirements says to only send host redirects */ 1406 type = ICMP_REDIRECT; 1407 code = ICMP_REDIRECT_HOST; 1408#ifdef DIAGNOSTIC 1409 if (ipprintfs) 1410 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1411#endif 1412 } 1413 } 1414 1415 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1416 IP_FORWARDING, 0); 1417 if (error) 1418 ipstat.ips_cantforward++; 1419 else { 1420 ipstat.ips_forward++; 1421 if (type) 1422 ipstat.ips_redirectsent++; 1423 else { 1424 if (mcopy) { 1425 ipflow_create(&ipforward_rt, mcopy); 1426 m_freem(mcopy); 1427 } 1428 return; 1429 } 1430 } 1431 if (mcopy == NULL) 1432 return; 1433 destifp = NULL; 1434 1435 switch (error) { 1436 1437 case 0: /* forwarded, but need redirect */ 1438 /* type, code set above */ 1439 break; 1440 1441 case ENETUNREACH: /* shouldn't happen, checked above */ 1442 case EHOSTUNREACH: 1443 case ENETDOWN: 1444 case EHOSTDOWN: 1445 default: 1446 type = ICMP_UNREACH; 1447 code = ICMP_UNREACH_HOST; 1448 break; 1449 1450 case EMSGSIZE: 1451 type = ICMP_UNREACH; 1452 code = ICMP_UNREACH_NEEDFRAG; 1453 if (ipforward_rt.ro_rt) 1454 destifp = ipforward_rt.ro_rt->rt_ifp; 1455 ipstat.ips_cantfrag++; 1456 break; 1457 1458 case ENOBUFS: 1459 type = ICMP_SOURCEQUENCH; 1460 code = 0; 1461 break; 1462 } 1463 icmp_error(mcopy, type, code, dest, destifp); 1464} 1465 1466void 1467ip_savecontrol(inp, mp, ip, m) 1468 register struct inpcb *inp; 1469 register struct mbuf **mp; 1470 register struct ip *ip; 1471 register struct mbuf *m; 1472{ 1473 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1474 struct timeval tv; 1475 1476 microtime(&tv); 1477 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1478 SCM_TIMESTAMP, SOL_SOCKET); 1479 if (*mp) 1480 mp = &(*mp)->m_next; 1481 } 1482 if (inp->inp_flags & INP_RECVDSTADDR) { 1483 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1484 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1485 if (*mp) 1486 mp = &(*mp)->m_next; 1487 } 1488#ifdef notyet 1489 /* XXX 1490 * Moving these out of udp_input() made them even more broken 1491 * than they already were. 1492 */ 1493 /* options were tossed already */ 1494 if (inp->inp_flags & INP_RECVOPTS) { 1495 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1496 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1497 if (*mp) 1498 mp = &(*mp)->m_next; 1499 } 1500 /* ip_srcroute doesn't do what we want here, need to fix */ 1501 if (inp->inp_flags & INP_RECVRETOPTS) { 1502 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1503 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1504 if (*mp) 1505 mp = &(*mp)->m_next; 1506 } 1507#endif 1508 if (inp->inp_flags & INP_RECVIF) { 1509 struct ifnet *ifp; 1510 struct sdlbuf { 1511 struct sockaddr_dl sdl; 1512 u_char pad[32]; 1513 } sdlbuf; 1514 struct sockaddr_dl *sdp; 1515 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1516 1517 if (((ifp = m->m_pkthdr.rcvif)) 1518 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1519 sdp = (struct sockaddr_dl *)(ifnet_addrs 1520 [ifp->if_index - 1]->ifa_addr); 1521 /* 1522 * Change our mind and don't try copy. 1523 */ 1524 if ((sdp->sdl_family != AF_LINK) 1525 || (sdp->sdl_len > sizeof(sdlbuf))) { 1526 goto makedummy; 1527 } 1528 bcopy(sdp, sdl2, sdp->sdl_len); 1529 } else { 1530makedummy: 1531 sdl2->sdl_len 1532 = offsetof(struct sockaddr_dl, sdl_data[0]); 1533 sdl2->sdl_family = AF_LINK; 1534 sdl2->sdl_index = 0; 1535 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1536 } 1537 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1538 IP_RECVIF, IPPROTO_IP); 1539 if (*mp) 1540 mp = &(*mp)->m_next; 1541 } 1542} 1543 1544int 1545ip_rsvp_init(struct socket *so) 1546{ 1547 if (so->so_type != SOCK_RAW || 1548 so->so_proto->pr_protocol != IPPROTO_RSVP) 1549 return EOPNOTSUPP; 1550 1551 if (ip_rsvpd != NULL) 1552 return EADDRINUSE; 1553 1554 ip_rsvpd = so; 1555 /* 1556 * This may seem silly, but we need to be sure we don't over-increment 1557 * the RSVP counter, in case something slips up. 1558 */ 1559 if (!ip_rsvp_on) { 1560 ip_rsvp_on = 1; 1561 rsvp_on++; 1562 } 1563 1564 return 0; 1565} 1566 1567int 1568ip_rsvp_done(void) 1569{ 1570 ip_rsvpd = NULL; 1571 /* 1572 * This may seem silly, but we need to be sure we don't over-decrement 1573 * the RSVP counter, in case something slips up. 1574 */ 1575 if (ip_rsvp_on) { 1576 ip_rsvp_on = 0; 1577 rsvp_on--; 1578 } 1579 return 0; 1580} 1581