ip_input.c revision 14230
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 1.36 1996/02/23 15:47:53 phk Exp $ 35 */ 36 37#include <sys/param.h> 38#include <sys/systm.h> 39#include <sys/malloc.h> 40#include <sys/mbuf.h> 41#include <sys/domain.h> 42#include <sys/protosw.h> 43#include <sys/socket.h> 44#include <sys/errno.h> 45#include <sys/time.h> 46#include <sys/kernel.h> 47#include <sys/syslog.h> 48#include <sys/sysctl.h> 49 50#include <net/if.h> 51#include <net/route.h> 52#include <net/netisr.h> 53 54#include <netinet/in.h> 55#include <netinet/in_systm.h> 56#include <netinet/in_var.h> 57#include <netinet/ip.h> 58#include <netinet/in_pcb.h> 59#include <netinet/in_var.h> 60#include <netinet/ip_var.h> 61#include <netinet/ip_icmp.h> 62 63#include <netinet/ip_fw.h> 64 65#include <sys/socketvar.h> 66int rsvp_on = 0; 67static int ip_rsvp_on; 68struct socket *ip_rsvpd; 69 70static int ipforwarding = 0; 71SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 72 &ipforwarding, 0, ""); 73 74static int ipsendredirects = 1; /* XXX */ 75SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 76 &ipsendredirects, 0, ""); 77 78int ip_defttl = IPDEFTTL; 79SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 80 &ip_defttl, 0, ""); 81 82static int ip_dosourceroute = 0; 83SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 84 &ip_dosourceroute, 0, ""); 85#ifdef DIAGNOSTIC 86static int ipprintfs = 0; 87#endif 88 89extern struct domain inetdomain; 90extern struct protosw inetsw[]; 91u_char ip_protox[IPPROTO_MAX]; 92static int ipqmaxlen = IFQ_MAXLEN; 93struct in_ifaddr *in_ifaddr; /* first inet address */ 94struct ifqueue ipintrq; 95SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RD, 96 &ipintrq.ifq_maxlen, 0, ""); 97SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 98 &ipintrq.ifq_drops, 0, ""); 99 100struct ipstat ipstat; 101static struct ipq ipq; 102 103#ifdef IPCTL_DEFMTU 104SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 105 &ip_mtu, 0, ""); 106#endif 107 108/* 109 * The dummy IP-firewall function, and the pointer we access it through 110 */ 111static int 112dummy_ip_fw_chk(m, ip, rif, dir) 113 struct mbuf *m; 114 struct ip *ip; 115 struct ifnet *rif; 116 int dir; 117{ 118 return 1; 119} 120 121int (*ip_fw_chk_ptr)(struct mbuf *, struct ip *, struct ifnet *, int dir) = 122 dummy_ip_fw_chk; 123 124int (*ip_fw_ctl_ptr)(int, struct mbuf *); 125 126/* 127 * We need to save the IP options in case a protocol wants to respond 128 * to an incoming packet over the same route if the packet got here 129 * using IP source routing. This allows connection establishment and 130 * maintenance when the remote end is on a network that is not known 131 * to us. 132 */ 133static int ip_nhops = 0; 134static struct ip_srcrt { 135 struct in_addr dst; /* final destination */ 136 char nop; /* one NOP to align */ 137 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 138 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 139} ip_srcrt; 140 141static void save_rte __P((u_char *, struct in_addr)); 142static void ip_deq __P((struct ipasfrag *)); 143static int ip_dooptions __P((struct mbuf *)); 144static void ip_enq __P((struct ipasfrag *, struct ipasfrag *)); 145static void ip_forward __P((struct mbuf *, int)); 146static void ip_freef __P((struct ipq *)); 147static struct ip * 148 ip_reass __P((struct ipasfrag *, struct ipq *)); 149static struct in_ifaddr * 150 ip_rtaddr __P((struct in_addr)); 151static void ipintr __P((void)); 152/* 153 * IP initialization: fill in IP protocol switch table. 154 * All protocols not implemented in kernel go to raw IP protocol handler. 155 */ 156void 157ip_init() 158{ 159 register struct protosw *pr; 160 register int i; 161 162 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 163 if (pr == 0) 164 panic("ip_init"); 165 for (i = 0; i < IPPROTO_MAX; i++) 166 ip_protox[i] = pr - inetsw; 167 for (pr = inetdomain.dom_protosw; 168 pr < inetdomain.dom_protoswNPROTOSW; pr++) 169 if (pr->pr_domain->dom_family == PF_INET && 170 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 171 ip_protox[pr->pr_protocol] = pr - inetsw; 172 ipq.next = ipq.prev = &ipq; 173 ip_id = time.tv_sec & 0xffff; 174 ipintrq.ifq_maxlen = ipqmaxlen; 175#ifdef IPFIREWALL 176 ip_fw_init(); 177#endif 178} 179 180static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 181static struct route ipforward_rt; 182 183/* 184 * Ip input routine. Checksum and byte swap header. If fragmented 185 * try to reassemble. Process options. Pass to next level. 186 */ 187void 188ip_input(struct mbuf *m) 189{ 190 register struct ip *ip; 191 register struct ipq *fp; 192 register struct in_ifaddr *ia; 193 int hlen, s; 194 195#ifdef DIAGNOSTIC 196 if ((m->m_flags & M_PKTHDR) == 0) 197 panic("ipintr no HDR"); 198#endif 199 /* 200 * If no IP addresses have been set yet but the interfaces 201 * are receiving, can't do anything with incoming packets yet. 202 */ 203 if (in_ifaddr == NULL) 204 goto bad; 205 ipstat.ips_total++; 206 if (m->m_len < sizeof (struct ip) && 207 (m = m_pullup(m, sizeof (struct ip))) == 0) { 208 ipstat.ips_toosmall++; 209 return; 210 } 211 ip = mtod(m, struct ip *); 212 if (ip->ip_v != IPVERSION) { 213 ipstat.ips_badvers++; 214 goto bad; 215 } 216 hlen = ip->ip_hl << 2; 217 if (hlen < sizeof(struct ip)) { /* minimum header length */ 218 ipstat.ips_badhlen++; 219 goto bad; 220 } 221 if (hlen > m->m_len) { 222 if ((m = m_pullup(m, hlen)) == 0) { 223 ipstat.ips_badhlen++; 224 return; 225 } 226 ip = mtod(m, struct ip *); 227 } 228 ip->ip_sum = in_cksum(m, hlen); 229 if (ip->ip_sum) { 230 ipstat.ips_badsum++; 231 goto bad; 232 } 233 234 /* 235 * Convert fields to host representation. 236 */ 237 NTOHS(ip->ip_len); 238 if (ip->ip_len < hlen) { 239 ipstat.ips_badlen++; 240 goto bad; 241 } 242 NTOHS(ip->ip_id); 243 NTOHS(ip->ip_off); 244 245 /* 246 * Check that the amount of data in the buffers 247 * is as at least much as the IP header would have us expect. 248 * Trim mbufs if longer than we expect. 249 * Drop packet if shorter than we expect. 250 */ 251 if (m->m_pkthdr.len < ip->ip_len) { 252 ipstat.ips_tooshort++; 253 goto bad; 254 } 255 if (m->m_pkthdr.len > ip->ip_len) { 256 if (m->m_len == m->m_pkthdr.len) { 257 m->m_len = ip->ip_len; 258 m->m_pkthdr.len = ip->ip_len; 259 } else 260 m_adj(m, ip->ip_len - m->m_pkthdr.len); 261 } 262 /* 263 * IpHack's section. 264 * Right now when no processing on packet has done 265 * and it is still fresh out of network we do our black 266 * deals with it. 267 * - Firewall: deny/allow 268 * - Wrap: fake packet's addr/port <unimpl.> 269 * - Encapsulate: put it in another IP and send out. <unimp.> 270 */ 271 272 if (!(*ip_fw_chk_ptr)(m,ip,m->m_pkthdr.rcvif,0)) 273 return; 274 275 /* 276 * Process options and, if not destined for us, 277 * ship it on. ip_dooptions returns 1 when an 278 * error was detected (causing an icmp message 279 * to be sent and the original packet to be freed). 280 */ 281 ip_nhops = 0; /* for source routed packets */ 282 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 283 return; 284 285 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 286 * matter if it is destined to another node, or whether it is 287 * a multicast one, RSVP wants it! and prevents it from being forwarded 288 * anywhere else. Also checks if the rsvp daemon is running before 289 * grabbing the packet. 290 */ 291 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 292 goto ours; 293 294 /* 295 * Check our list of addresses, to see if the packet is for us. 296 */ 297 for (ia = in_ifaddr; ia; ia = ia->ia_next) { 298#define satosin(sa) ((struct sockaddr_in *)(sa)) 299 300 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 301 goto ours; 302 if (ia->ia_ifp->if_flags & IFF_BROADCAST) { 303#if 0 304 u_long t; 305#endif 306 307 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 308 ip->ip_dst.s_addr) 309 goto ours; 310 if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr) 311 goto ours; 312#if 0 /* XXX - this should go away */ 313 /* 314 * Look for all-0's host part (old broadcast addr), 315 * either for subnet or net. 316 */ 317 t = ntohl(ip->ip_dst.s_addr); 318 if (t == ia->ia_subnet) 319 goto ours; 320 if (t == ia->ia_net) 321 goto ours; 322#endif /* compatibility cruft */ 323 } 324 } 325 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 326 struct in_multi *inm; 327 if (ip_mrouter) { 328 /* 329 * If we are acting as a multicast router, all 330 * incoming multicast packets are passed to the 331 * kernel-level multicast forwarding function. 332 * The packet is returned (relatively) intact; if 333 * ip_mforward() returns a non-zero value, the packet 334 * must be discarded, else it may be accepted below. 335 * 336 * (The IP ident field is put in the same byte order 337 * as expected when ip_mforward() is called from 338 * ip_output().) 339 */ 340 ip->ip_id = htons(ip->ip_id); 341 if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 342 ipstat.ips_cantforward++; 343 m_freem(m); 344 return; 345 } 346 ip->ip_id = ntohs(ip->ip_id); 347 348 /* 349 * The process-level routing demon needs to receive 350 * all multicast IGMP packets, whether or not this 351 * host belongs to their destination groups. 352 */ 353 if (ip->ip_p == IPPROTO_IGMP) 354 goto ours; 355 ipstat.ips_forward++; 356 } 357 /* 358 * See if we belong to the destination multicast group on the 359 * arrival interface. 360 */ 361 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 362 if (inm == NULL) { 363 ipstat.ips_cantforward++; 364 m_freem(m); 365 return; 366 } 367 goto ours; 368 } 369 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 370 goto ours; 371 if (ip->ip_dst.s_addr == INADDR_ANY) 372 goto ours; 373 374 /* 375 * Not for us; forward if possible and desirable. 376 */ 377 if (ipforwarding == 0) { 378 ipstat.ips_cantforward++; 379 m_freem(m); 380 } else 381 ip_forward(m, 0); 382 return; 383 384ours: 385 386 /* 387 * If offset or IP_MF are set, must reassemble. 388 * Otherwise, nothing need be done. 389 * (We could look in the reassembly queue to see 390 * if the packet was previously fragmented, 391 * but it's not worth the time; just let them time out.) 392 */ 393 if (ip->ip_off &~ IP_DF) { 394 if (m->m_flags & M_EXT) { /* XXX */ 395 if ((m = m_pullup(m, sizeof (struct ip))) == 0) { 396 ipstat.ips_toosmall++; 397 return; 398 } 399 ip = mtod(m, struct ip *); 400 } 401 /* 402 * Look for queue of fragments 403 * of this datagram. 404 */ 405 for (fp = ipq.next; fp != &ipq; fp = fp->next) 406 if (ip->ip_id == fp->ipq_id && 407 ip->ip_src.s_addr == fp->ipq_src.s_addr && 408 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 409 ip->ip_p == fp->ipq_p) 410 goto found; 411 fp = 0; 412found: 413 414 /* 415 * Adjust ip_len to not reflect header, 416 * set ip_mff if more fragments are expected, 417 * convert offset of this to bytes. 418 */ 419 ip->ip_len -= hlen; 420 ((struct ipasfrag *)ip)->ipf_mff &= ~1; 421 if (ip->ip_off & IP_MF) 422 ((struct ipasfrag *)ip)->ipf_mff |= 1; 423 ip->ip_off <<= 3; 424 425 /* 426 * If datagram marked as having more fragments 427 * or if this is not the first fragment, 428 * attempt reassembly; if it succeeds, proceed. 429 */ 430 if (((struct ipasfrag *)ip)->ipf_mff & 1 || ip->ip_off) { 431 ipstat.ips_fragments++; 432 ip = ip_reass((struct ipasfrag *)ip, fp); 433 if (ip == 0) 434 return; 435 ipstat.ips_reassembled++; 436 m = dtom(ip); 437 } else 438 if (fp) 439 ip_freef(fp); 440 } else 441 ip->ip_len -= hlen; 442 443 /* 444 * Switch out to protocol's input routine. 445 */ 446 ipstat.ips_delivered++; 447 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 448 return; 449bad: 450 m_freem(m); 451} 452 453/* 454 * IP software interrupt routine - to go away sometime soon 455 */ 456static void 457ipintr(void) 458{ 459 int s; 460 struct mbuf *m; 461 462 while(1) { 463 s = splimp(); 464 IF_DEQUEUE(&ipintrq, m); 465 splx(s); 466 if (m == 0) 467 return; 468 ip_input(m); 469 } 470} 471 472NETISR_SET(NETISR_IP, ipintr); 473 474/* 475 * Take incoming datagram fragment and try to 476 * reassemble it into whole datagram. If a chain for 477 * reassembly of this datagram already exists, then it 478 * is given as fp; otherwise have to make a chain. 479 */ 480static struct ip * 481ip_reass(ip, fp) 482 register struct ipasfrag *ip; 483 register struct ipq *fp; 484{ 485 register struct mbuf *m = dtom(ip); 486 register struct ipasfrag *q; 487 struct mbuf *t; 488 int hlen = ip->ip_hl << 2; 489 int i, next; 490 491 /* 492 * Presence of header sizes in mbufs 493 * would confuse code below. 494 */ 495 m->m_data += hlen; 496 m->m_len -= hlen; 497 498 /* 499 * If first fragment to arrive, create a reassembly queue. 500 */ 501 if (fp == 0) { 502 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 503 goto dropfrag; 504 fp = mtod(t, struct ipq *); 505 insque(fp, &ipq); 506 fp->ipq_ttl = IPFRAGTTL; 507 fp->ipq_p = ip->ip_p; 508 fp->ipq_id = ip->ip_id; 509 fp->ipq_next = fp->ipq_prev = (struct ipasfrag *)fp; 510 fp->ipq_src = ((struct ip *)ip)->ip_src; 511 fp->ipq_dst = ((struct ip *)ip)->ip_dst; 512 q = (struct ipasfrag *)fp; 513 goto insert; 514 } 515 516 /* 517 * Find a segment which begins after this one does. 518 */ 519 for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) 520 if (q->ip_off > ip->ip_off) 521 break; 522 523 /* 524 * If there is a preceding segment, it may provide some of 525 * our data already. If so, drop the data from the incoming 526 * segment. If it provides all of our data, drop us. 527 */ 528 if (q->ipf_prev != (struct ipasfrag *)fp) { 529 i = q->ipf_prev->ip_off + q->ipf_prev->ip_len - ip->ip_off; 530 if (i > 0) { 531 if (i >= ip->ip_len) 532 goto dropfrag; 533 m_adj(dtom(ip), i); 534 ip->ip_off += i; 535 ip->ip_len -= i; 536 } 537 } 538 539 /* 540 * While we overlap succeeding segments trim them or, 541 * if they are completely covered, dequeue them. 542 */ 543 while (q != (struct ipasfrag *)fp && ip->ip_off + ip->ip_len > q->ip_off) { 544 i = (ip->ip_off + ip->ip_len) - q->ip_off; 545 if (i < q->ip_len) { 546 q->ip_len -= i; 547 q->ip_off += i; 548 m_adj(dtom(q), i); 549 break; 550 } 551 q = q->ipf_next; 552 m_freem(dtom(q->ipf_prev)); 553 ip_deq(q->ipf_prev); 554 } 555 556insert: 557 /* 558 * Stick new segment in its place; 559 * check for complete reassembly. 560 */ 561 ip_enq(ip, q->ipf_prev); 562 next = 0; 563 for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) { 564 if (q->ip_off != next) 565 return (0); 566 next += q->ip_len; 567 } 568 if (q->ipf_prev->ipf_mff & 1) 569 return (0); 570 571 /* 572 * Reassembly is complete; concatenate fragments. 573 */ 574 q = fp->ipq_next; 575 m = dtom(q); 576 t = m->m_next; 577 m->m_next = 0; 578 m_cat(m, t); 579 q = q->ipf_next; 580 while (q != (struct ipasfrag *)fp) { 581 t = dtom(q); 582 q = q->ipf_next; 583 m_cat(m, t); 584 } 585 586 /* 587 * Create header for new ip packet by 588 * modifying header of first packet; 589 * dequeue and discard fragment reassembly header. 590 * Make header visible. 591 */ 592 ip = fp->ipq_next; 593 ip->ip_len = next; 594 ip->ipf_mff &= ~1; 595 ((struct ip *)ip)->ip_src = fp->ipq_src; 596 ((struct ip *)ip)->ip_dst = fp->ipq_dst; 597 remque(fp); 598 (void) m_free(dtom(fp)); 599 m = dtom(ip); 600 m->m_len += (ip->ip_hl << 2); 601 m->m_data -= (ip->ip_hl << 2); 602 /* some debugging cruft by sklower, below, will go away soon */ 603 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 604 register int plen = 0; 605 for (t = m; m; m = m->m_next) 606 plen += m->m_len; 607 t->m_pkthdr.len = plen; 608 } 609 return ((struct ip *)ip); 610 611dropfrag: 612 ipstat.ips_fragdropped++; 613 m_freem(m); 614 return (0); 615} 616 617/* 618 * Free a fragment reassembly header and all 619 * associated datagrams. 620 */ 621static void 622ip_freef(fp) 623 struct ipq *fp; 624{ 625 register struct ipasfrag *q, *p; 626 627 for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = p) { 628 p = q->ipf_next; 629 ip_deq(q); 630 m_freem(dtom(q)); 631 } 632 remque(fp); 633 (void) m_free(dtom(fp)); 634} 635 636/* 637 * Put an ip fragment on a reassembly chain. 638 * Like insque, but pointers in middle of structure. 639 */ 640static void 641ip_enq(p, prev) 642 register struct ipasfrag *p, *prev; 643{ 644 645 p->ipf_prev = prev; 646 p->ipf_next = prev->ipf_next; 647 prev->ipf_next->ipf_prev = p; 648 prev->ipf_next = p; 649} 650 651/* 652 * To ip_enq as remque is to insque. 653 */ 654static void 655ip_deq(p) 656 register struct ipasfrag *p; 657{ 658 659 p->ipf_prev->ipf_next = p->ipf_next; 660 p->ipf_next->ipf_prev = p->ipf_prev; 661} 662 663/* 664 * IP timer processing; 665 * if a timer expires on a reassembly 666 * queue, discard it. 667 */ 668void 669ip_slowtimo() 670{ 671 register struct ipq *fp; 672 int s = splnet(); 673 674 fp = ipq.next; 675 if (fp == 0) { 676 splx(s); 677 return; 678 } 679 while (fp != &ipq) { 680 --fp->ipq_ttl; 681 fp = fp->next; 682 if (fp->prev->ipq_ttl == 0) { 683 ipstat.ips_fragtimeout++; 684 ip_freef(fp->prev); 685 } 686 } 687 splx(s); 688} 689 690/* 691 * Drain off all datagram fragments. 692 */ 693void 694ip_drain() 695{ 696 while (ipq.next != &ipq) { 697 ipstat.ips_fragdropped++; 698 ip_freef(ipq.next); 699 } 700 701 in_rtqdrain(); 702} 703 704/* 705 * Do option processing on a datagram, 706 * possibly discarding it if bad options are encountered, 707 * or forwarding it if source-routed. 708 * Returns 1 if packet has been forwarded/freed, 709 * 0 if the packet should be processed further. 710 */ 711static int 712ip_dooptions(m) 713 struct mbuf *m; 714{ 715 register struct ip *ip = mtod(m, struct ip *); 716 register u_char *cp; 717 register struct ip_timestamp *ipt; 718 register struct in_ifaddr *ia; 719 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 720 struct in_addr *sin, dst; 721 n_time ntime; 722 723 dst = ip->ip_dst; 724 cp = (u_char *)(ip + 1); 725 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 726 for (; cnt > 0; cnt -= optlen, cp += optlen) { 727 opt = cp[IPOPT_OPTVAL]; 728 if (opt == IPOPT_EOL) 729 break; 730 if (opt == IPOPT_NOP) 731 optlen = 1; 732 else { 733 optlen = cp[IPOPT_OLEN]; 734 if (optlen <= 0 || optlen > cnt) { 735 code = &cp[IPOPT_OLEN] - (u_char *)ip; 736 goto bad; 737 } 738 } 739 switch (opt) { 740 741 default: 742 break; 743 744 /* 745 * Source routing with record. 746 * Find interface with current destination address. 747 * If none on this machine then drop if strictly routed, 748 * or do nothing if loosely routed. 749 * Record interface address and bring up next address 750 * component. If strictly routed make sure next 751 * address is on directly accessible net. 752 */ 753 case IPOPT_LSRR: 754 case IPOPT_SSRR: 755 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 756 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 757 goto bad; 758 } 759 ipaddr.sin_addr = ip->ip_dst; 760 ia = (struct in_ifaddr *) 761 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 762 if (ia == 0) { 763 if (opt == IPOPT_SSRR) { 764 type = ICMP_UNREACH; 765 code = ICMP_UNREACH_SRCFAIL; 766 goto bad; 767 } 768 /* 769 * Loose routing, and not at next destination 770 * yet; nothing to do except forward. 771 */ 772 break; 773 } 774 off--; /* 0 origin */ 775 if (off > optlen - sizeof(struct in_addr)) { 776 /* 777 * End of source route. Should be for us. 778 */ 779 save_rte(cp, ip->ip_src); 780 break; 781 } 782 783 if (!ip_dosourceroute) { 784 char buf[4*sizeof "123"]; 785 strcpy(buf, inet_ntoa(ip->ip_dst)); 786 787 log(LOG_WARNING, 788 "attempted source route from %s to %s\n", 789 inet_ntoa(ip->ip_src), buf); 790 type = ICMP_UNREACH; 791 code = ICMP_UNREACH_SRCFAIL; 792 goto bad; 793 } 794 795 /* 796 * locate outgoing interface 797 */ 798 (void)memcpy(&ipaddr.sin_addr, cp + off, 799 sizeof(ipaddr.sin_addr)); 800 801 if (opt == IPOPT_SSRR) { 802#define INA struct in_ifaddr * 803#define SA struct sockaddr * 804 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 805 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 806 } else 807 ia = ip_rtaddr(ipaddr.sin_addr); 808 if (ia == 0) { 809 type = ICMP_UNREACH; 810 code = ICMP_UNREACH_SRCFAIL; 811 goto bad; 812 } 813 ip->ip_dst = ipaddr.sin_addr; 814 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 815 sizeof(struct in_addr)); 816 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 817 /* 818 * Let ip_intr's mcast routing check handle mcast pkts 819 */ 820 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 821 break; 822 823 case IPOPT_RR: 824 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 825 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 826 goto bad; 827 } 828 /* 829 * If no space remains, ignore. 830 */ 831 off--; /* 0 origin */ 832 if (off > optlen - sizeof(struct in_addr)) 833 break; 834 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 835 sizeof(ipaddr.sin_addr)); 836 /* 837 * locate outgoing interface; if we're the destination, 838 * use the incoming interface (should be same). 839 */ 840 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 841 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 842 type = ICMP_UNREACH; 843 code = ICMP_UNREACH_HOST; 844 goto bad; 845 } 846 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 847 sizeof(struct in_addr)); 848 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 849 break; 850 851 case IPOPT_TS: 852 code = cp - (u_char *)ip; 853 ipt = (struct ip_timestamp *)cp; 854 if (ipt->ipt_len < 5) 855 goto bad; 856 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (long)) { 857 if (++ipt->ipt_oflw == 0) 858 goto bad; 859 break; 860 } 861 sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); 862 switch (ipt->ipt_flg) { 863 864 case IPOPT_TS_TSONLY: 865 break; 866 867 case IPOPT_TS_TSANDADDR: 868 if (ipt->ipt_ptr + sizeof(n_time) + 869 sizeof(struct in_addr) > ipt->ipt_len) 870 goto bad; 871 ipaddr.sin_addr = dst; 872 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 873 m->m_pkthdr.rcvif); 874 if (ia == 0) 875 continue; 876 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 877 sizeof(struct in_addr)); 878 ipt->ipt_ptr += sizeof(struct in_addr); 879 break; 880 881 case IPOPT_TS_PRESPEC: 882 if (ipt->ipt_ptr + sizeof(n_time) + 883 sizeof(struct in_addr) > ipt->ipt_len) 884 goto bad; 885 (void)memcpy(&ipaddr.sin_addr, sin, 886 sizeof(struct in_addr)); 887 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 888 continue; 889 ipt->ipt_ptr += sizeof(struct in_addr); 890 break; 891 892 default: 893 goto bad; 894 } 895 ntime = iptime(); 896 (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime, 897 sizeof(n_time)); 898 ipt->ipt_ptr += sizeof(n_time); 899 } 900 } 901 if (forward) { 902 ip_forward(m, 1); 903 return (1); 904 } 905 return (0); 906bad: 907 ip->ip_len -= ip->ip_hl << 2; /* XXX icmp_error adds in hdr length */ 908 icmp_error(m, type, code, 0, 0); 909 ipstat.ips_badoptions++; 910 return (1); 911} 912 913/* 914 * Given address of next destination (final or next hop), 915 * return internet address info of interface to be used to get there. 916 */ 917static struct in_ifaddr * 918ip_rtaddr(dst) 919 struct in_addr dst; 920{ 921 register struct sockaddr_in *sin; 922 923 sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; 924 925 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 926 if (ipforward_rt.ro_rt) { 927 RTFREE(ipforward_rt.ro_rt); 928 ipforward_rt.ro_rt = 0; 929 } 930 sin->sin_family = AF_INET; 931 sin->sin_len = sizeof(*sin); 932 sin->sin_addr = dst; 933 934 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 935 } 936 if (ipforward_rt.ro_rt == 0) 937 return ((struct in_ifaddr *)0); 938 return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); 939} 940 941/* 942 * Save incoming source route for use in replies, 943 * to be picked up later by ip_srcroute if the receiver is interested. 944 */ 945void 946save_rte(option, dst) 947 u_char *option; 948 struct in_addr dst; 949{ 950 unsigned olen; 951 952 olen = option[IPOPT_OLEN]; 953#ifdef DIAGNOSTIC 954 if (ipprintfs) 955 printf("save_rte: olen %d\n", olen); 956#endif 957 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 958 return; 959 (void)memcpy(ip_srcrt.srcopt, option, olen); 960 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 961 ip_srcrt.dst = dst; 962} 963 964/* 965 * Retrieve incoming source route for use in replies, 966 * in the same form used by setsockopt. 967 * The first hop is placed before the options, will be removed later. 968 */ 969struct mbuf * 970ip_srcroute() 971{ 972 register struct in_addr *p, *q; 973 register struct mbuf *m; 974 975 if (ip_nhops == 0) 976 return ((struct mbuf *)0); 977 m = m_get(M_DONTWAIT, MT_SOOPTS); 978 if (m == 0) 979 return ((struct mbuf *)0); 980 981#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 982 983 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 984 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 985 OPTSIZ; 986#ifdef DIAGNOSTIC 987 if (ipprintfs) 988 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 989#endif 990 991 /* 992 * First save first hop for return route 993 */ 994 p = &ip_srcrt.route[ip_nhops - 1]; 995 *(mtod(m, struct in_addr *)) = *p--; 996#ifdef DIAGNOSTIC 997 if (ipprintfs) 998 printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr)); 999#endif 1000 1001 /* 1002 * Copy option fields and padding (nop) to mbuf. 1003 */ 1004 ip_srcrt.nop = IPOPT_NOP; 1005 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1006 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1007 &ip_srcrt.nop, OPTSIZ); 1008 q = (struct in_addr *)(mtod(m, caddr_t) + 1009 sizeof(struct in_addr) + OPTSIZ); 1010#undef OPTSIZ 1011 /* 1012 * Record return path as an IP source route, 1013 * reversing the path (pointers are now aligned). 1014 */ 1015 while (p >= ip_srcrt.route) { 1016#ifdef DIAGNOSTIC 1017 if (ipprintfs) 1018 printf(" %lx", ntohl(q->s_addr)); 1019#endif 1020 *q++ = *p--; 1021 } 1022 /* 1023 * Last hop goes to final destination. 1024 */ 1025 *q = ip_srcrt.dst; 1026#ifdef DIAGNOSTIC 1027 if (ipprintfs) 1028 printf(" %lx\n", ntohl(q->s_addr)); 1029#endif 1030 return (m); 1031} 1032 1033/* 1034 * Strip out IP options, at higher 1035 * level protocol in the kernel. 1036 * Second argument is buffer to which options 1037 * will be moved, and return value is their length. 1038 * XXX should be deleted; last arg currently ignored. 1039 */ 1040void 1041ip_stripoptions(m, mopt) 1042 register struct mbuf *m; 1043 struct mbuf *mopt; 1044{ 1045 register int i; 1046 struct ip *ip = mtod(m, struct ip *); 1047 register caddr_t opts; 1048 int olen; 1049 1050 olen = (ip->ip_hl<<2) - sizeof (struct ip); 1051 opts = (caddr_t)(ip + 1); 1052 i = m->m_len - (sizeof (struct ip) + olen); 1053 bcopy(opts + olen, opts, (unsigned)i); 1054 m->m_len -= olen; 1055 if (m->m_flags & M_PKTHDR) 1056 m->m_pkthdr.len -= olen; 1057 ip->ip_hl = sizeof(struct ip) >> 2; 1058} 1059 1060u_char inetctlerrmap[PRC_NCMDS] = { 1061 0, 0, 0, 0, 1062 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1063 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1064 EMSGSIZE, EHOSTUNREACH, 0, 0, 1065 0, 0, 0, 0, 1066 ENOPROTOOPT 1067}; 1068 1069/* 1070 * Forward a packet. If some error occurs return the sender 1071 * an icmp packet. Note we can't always generate a meaningful 1072 * icmp message because icmp doesn't have a large enough repertoire 1073 * of codes and types. 1074 * 1075 * If not forwarding, just drop the packet. This could be confusing 1076 * if ipforwarding was zero but some routing protocol was advancing 1077 * us as a gateway to somewhere. However, we must let the routing 1078 * protocol deal with that. 1079 * 1080 * The srcrt parameter indicates whether the packet is being forwarded 1081 * via a source route. 1082 */ 1083static void 1084ip_forward(m, srcrt) 1085 struct mbuf *m; 1086 int srcrt; 1087{ 1088 register struct ip *ip = mtod(m, struct ip *); 1089 register struct sockaddr_in *sin; 1090 register struct rtentry *rt; 1091 int error, type = 0, code = 0; 1092 struct mbuf *mcopy; 1093 n_long dest; 1094 struct ifnet *destifp; 1095 1096 dest = 0; 1097#ifdef DIAGNOSTIC 1098 if (ipprintfs) 1099 printf("forward: src %lx dst %lx ttl %x\n", 1100 ip->ip_src.s_addr, ip->ip_dst.s_addr, ip->ip_ttl); 1101#endif 1102 1103 1104 if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) { 1105 ipstat.ips_cantforward++; 1106 m_freem(m); 1107 return; 1108 } 1109 HTONS(ip->ip_id); 1110 if (ip->ip_ttl <= IPTTLDEC) { 1111 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1112 return; 1113 } 1114 ip->ip_ttl -= IPTTLDEC; 1115 1116 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1117 if ((rt = ipforward_rt.ro_rt) == 0 || 1118 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1119 if (ipforward_rt.ro_rt) { 1120 RTFREE(ipforward_rt.ro_rt); 1121 ipforward_rt.ro_rt = 0; 1122 } 1123 sin->sin_family = AF_INET; 1124 sin->sin_len = sizeof(*sin); 1125 sin->sin_addr = ip->ip_dst; 1126 1127 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1128 if (ipforward_rt.ro_rt == 0) { 1129 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1130 return; 1131 } 1132 rt = ipforward_rt.ro_rt; 1133 } 1134 1135 /* 1136 * Save at most 64 bytes of the packet in case 1137 * we need to generate an ICMP message to the src. 1138 */ 1139 mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); 1140 1141 /* 1142 * If forwarding packet using same interface that it came in on, 1143 * perhaps should send a redirect to sender to shortcut a hop. 1144 * Only send redirect if source is sending directly to us, 1145 * and if packet was not source routed (or has any options). 1146 * Also, don't send redirect if forwarding using a default route 1147 * or a route modified by a redirect. 1148 */ 1149#define satosin(sa) ((struct sockaddr_in *)(sa)) 1150 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1151 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1152 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1153 ipsendredirects && !srcrt) { 1154#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1155 u_long src = ntohl(ip->ip_src.s_addr); 1156 1157 if (RTA(rt) && 1158 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1159 if (rt->rt_flags & RTF_GATEWAY) 1160 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1161 else 1162 dest = ip->ip_dst.s_addr; 1163 /* Router requirements says to only send host redirects */ 1164 type = ICMP_REDIRECT; 1165 code = ICMP_REDIRECT_HOST; 1166#ifdef DIAGNOSTIC 1167 if (ipprintfs) 1168 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1169#endif 1170 } 1171 } 1172 1173 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1174 IP_FORWARDING, 0); 1175 if (error) 1176 ipstat.ips_cantforward++; 1177 else { 1178 ipstat.ips_forward++; 1179 if (type) 1180 ipstat.ips_redirectsent++; 1181 else { 1182 if (mcopy) 1183 m_freem(mcopy); 1184 return; 1185 } 1186 } 1187 if (mcopy == NULL) 1188 return; 1189 destifp = NULL; 1190 1191 switch (error) { 1192 1193 case 0: /* forwarded, but need redirect */ 1194 /* type, code set above */ 1195 break; 1196 1197 case ENETUNREACH: /* shouldn't happen, checked above */ 1198 case EHOSTUNREACH: 1199 case ENETDOWN: 1200 case EHOSTDOWN: 1201 default: 1202 type = ICMP_UNREACH; 1203 code = ICMP_UNREACH_HOST; 1204 break; 1205 1206 case EMSGSIZE: 1207 type = ICMP_UNREACH; 1208 code = ICMP_UNREACH_NEEDFRAG; 1209 if (ipforward_rt.ro_rt) 1210 destifp = ipforward_rt.ro_rt->rt_ifp; 1211 ipstat.ips_cantfrag++; 1212 break; 1213 1214 case ENOBUFS: 1215 type = ICMP_SOURCEQUENCH; 1216 code = 0; 1217 break; 1218 } 1219 icmp_error(mcopy, type, code, dest, destifp); 1220} 1221 1222int 1223ip_rsvp_init(struct socket *so) 1224{ 1225 if (so->so_type != SOCK_RAW || 1226 so->so_proto->pr_protocol != IPPROTO_RSVP) 1227 return EOPNOTSUPP; 1228 1229 if (ip_rsvpd != NULL) 1230 return EADDRINUSE; 1231 1232 ip_rsvpd = so; 1233 /* 1234 * This may seem silly, but we need to be sure we don't over-increment 1235 * the RSVP counter, in case something slips up. 1236 */ 1237 if (!ip_rsvp_on) { 1238 ip_rsvp_on = 1; 1239 rsvp_on++; 1240 } 1241 1242 return 0; 1243} 1244 1245int 1246ip_rsvp_done(void) 1247{ 1248 ip_rsvpd = NULL; 1249 /* 1250 * This may seem silly, but we need to be sure we don't over-decrement 1251 * the RSVP counter, in case something slips up. 1252 */ 1253 if (ip_rsvp_on) { 1254 ip_rsvp_on = 0; 1255 rsvp_on--; 1256 } 1257 return 0; 1258} 1259