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 1.13 1994/12/13 23:08:11 wollman 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 48 #include <net/if.h> 49 #include <net/route.h> 50 51 #include <netinet/in.h> 52 #include <netinet/in_systm.h> 53 #include <netinet/ip.h> 54 #include <netinet/in_pcb.h> 55 #include <netinet/in_var.h> 56 #include <netinet/ip_var.h> 57 #include <netinet/ip_icmp.h> 58 59 #ifdef IPFIREWALL 60 #include <netinet/ip_fw.h> 61 #endif 62 #ifdef IPACCT 63 #include <netinet/ip_fw.h> 64 #endif 65 66 #include <sys/socketvar.h> 67 struct socket *ip_rsvpd; 68 69 #ifndef IPFORWARDING 70 #ifdef GATEWAY 71 #define IPFORWARDING 1 /* forward IP packets not for us */ 72 #else /* GATEWAY */ 73 #define IPFORWARDING 0 /* don't forward IP packets not for us */ 74 #endif /* GATEWAY */ 75 #endif /* IPFORWARDING */ 76 #ifndef IPSENDREDIRECTS 77 #define IPSENDREDIRECTS 1 78 #endif 79 int ipforwarding = IPFORWARDING; 80 int ipsendredirects = IPSENDREDIRECTS; 81 int ip_defttl = IPDEFTTL; 82 #ifdef DIAGNOSTIC 83 int ipprintfs = 0; 84 #endif 85 86 extern struct domain inetdomain; 87 extern struct protosw inetsw[]; 88 u_char ip_protox[IPPROTO_MAX]; 89 int ipqmaxlen = IFQ_MAXLEN; 90 struct in_ifaddr *in_ifaddr; /* first inet address */ 91 struct ifqueue ipintrq; 92 93 struct ipstat ipstat; 94 struct ipq ipq; 95 96 /* 97 * We need to save the IP options in case a protocol wants to respond 98 * to an incoming packet over the same route if the packet got here 99 * using IP source routing. This allows connection establishment and 100 * maintenance when the remote end is on a network that is not known 101 * to us. 102 */ 103 int ip_nhops = 0; 104 static struct ip_srcrt { 105 struct in_addr dst; /* final destination */ 106 char nop; /* one NOP to align */ 107 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 108 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 109 } ip_srcrt; 110 111 #ifdef GATEWAY 112 extern int if_index; 113 u_long *ip_ifmatrix; 114 #endif 115 116 static void save_rte __P((u_char *, struct in_addr)); 117 /* 118 * IP initialization: fill in IP protocol switch table. 119 * All protocols not implemented in kernel go to raw IP protocol handler. 120 */ 121 void 122 ip_init() 123 { 124 register struct protosw *pr; 125 register int i; 126 127 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 128 if (pr == 0) 129 panic("ip_init"); 130 for (i = 0; i < IPPROTO_MAX; i++) 131 ip_protox[i] = pr - inetsw; 132 for (pr = inetdomain.dom_protosw; 133 pr < inetdomain.dom_protoswNPROTOSW; pr++) 134 if (pr->pr_domain->dom_family == PF_INET && 135 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 136 ip_protox[pr->pr_protocol] = pr - inetsw; 137 ipq.next = ipq.prev = &ipq; 138 ip_id = time.tv_sec & 0xffff; 139 ipintrq.ifq_maxlen = ipqmaxlen; 140 #ifdef GATEWAY 141 i = (if_index + 1) * (if_index + 1) * sizeof (u_long); 142 ip_ifmatrix = (u_long *) malloc(i, M_RTABLE, M_WAITOK); 143 bzero((char *)ip_ifmatrix, i); 144 #endif 145 } 146 147 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 148 struct route ipforward_rt; 149 150 /* 151 * Ip input routine. Checksum and byte swap header. If fragmented 152 * try to reassemble. Process options. Pass to next level. 153 */ 154 void 155 ipintr() 156 { 157 register struct ip *ip; 158 register struct mbuf *m; 159 register struct ipq *fp; 160 register struct in_ifaddr *ia; 161 int hlen, s; 162 163 next: 164 /* 165 * Get next datagram off input queue and get IP header 166 * in first mbuf. 167 */ 168 s = splimp(); 169 IF_DEQUEUE(&ipintrq, m); 170 splx(s); 171 if (m == 0) 172 return; 173 #ifdef DIAGNOSTIC 174 if ((m->m_flags & M_PKTHDR) == 0) 175 panic("ipintr no HDR"); 176 #endif 177 /* 178 * If no IP addresses have been set yet but the interfaces 179 * are receiving, can't do anything with incoming packets yet. 180 */ 181 if (in_ifaddr == NULL) 182 goto bad; 183 ipstat.ips_total++; 184 if (m->m_len < sizeof (struct ip) && 185 (m = m_pullup(m, sizeof (struct ip))) == 0) { 186 ipstat.ips_toosmall++; 187 goto next; 188 } 189 ip = mtod(m, struct ip *); 190 if (ip->ip_v != IPVERSION) { 191 ipstat.ips_badvers++; 192 goto bad; 193 } 194 hlen = ip->ip_hl << 2; 195 if (hlen < sizeof(struct ip)) { /* minimum header length */ 196 ipstat.ips_badhlen++; 197 goto bad; 198 } 199 if (hlen > m->m_len) { 200 if ((m = m_pullup(m, hlen)) == 0) { 201 ipstat.ips_badhlen++; 202 goto next; 203 } 204 ip = mtod(m, struct ip *); 205 } 206 ip->ip_sum = in_cksum(m, hlen); 207 if (ip->ip_sum) { 208 ipstat.ips_badsum++; 209 goto bad; 210 } 211 212 /* 213 * Convert fields to host representation. 214 */ 215 NTOHS(ip->ip_len); 216 if (ip->ip_len < hlen) { 217 ipstat.ips_badlen++; 218 goto bad; 219 } 220 NTOHS(ip->ip_id); 221 NTOHS(ip->ip_off); 222 223 /* 224 * Check that the amount of data in the buffers 225 * is as at least much as the IP header would have us expect. 226 * Trim mbufs if longer than we expect. 227 * Drop packet if shorter than we expect. 228 */ 229 if (m->m_pkthdr.len < ip->ip_len) { 230 ipstat.ips_tooshort++; 231 goto bad; 232 } 233 if (m->m_pkthdr.len > ip->ip_len) { 234 if (m->m_len == m->m_pkthdr.len) { 235 m->m_len = ip->ip_len; 236 m->m_pkthdr.len = ip->ip_len; 237 } else 238 m_adj(m, ip->ip_len - m->m_pkthdr.len); 239 } 240 241 #ifdef IPFIREWALL 242 if ( ((char *)&(ip->ip_dst.s_addr))[0] != 127 243 && !ip_fw_chk(ip,m->m_pkthdr.rcvif,ip_fw_blk_chain) ) { 244 goto bad; 245 } 246 #endif 247 248 /* 249 * Process options and, if not destined for us, 250 * ship it on. ip_dooptions returns 1 when an 251 * error was detected (causing an icmp message 252 * to be sent and the original packet to be freed). 253 */ 254 ip_nhops = 0; /* for source routed packets */ 255 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 256 goto next; 257 258 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 259 * matter if it is destined to another node, or whether it is 260 * a multicast one, RSVP wants it! and prevents it from being forwarded 261 * anywhere else. Also checks if the rsvp daemon is running before 262 * grabbing the packet. 263 */ 264 if (ip_rsvpd != NULL && ip->ip_p==IPPROTO_RSVP) 265 goto ours; 266 267 /* 268 * Check our list of addresses, to see if the packet is for us. 269 */ 270 for (ia = in_ifaddr; ia; ia = ia->ia_next) { 271 #define satosin(sa) ((struct sockaddr_in *)(sa)) 272 273 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 274 goto ours; 275 if ( 276 #ifdef DIRECTED_BROADCAST 277 ia->ia_ifp == m->m_pkthdr.rcvif && 278 #endif 279 (ia->ia_ifp->if_flags & IFF_BROADCAST)) { 280 u_long t; 281 282 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 283 ip->ip_dst.s_addr) 284 goto ours; 285 if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr) 286 goto ours; 287 /* 288 * Look for all-0's host part (old broadcast addr), 289 * either for subnet or net. 290 */ 291 t = ntohl(ip->ip_dst.s_addr); 292 if (t == ia->ia_subnet) 293 goto ours; 294 if (t == ia->ia_net) 295 goto ours; 296 } 297 } 298 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 299 struct in_multi *inm; 300 if (ip_mrouter) { 301 /* 302 * If we are acting as a multicast router, all 303 * incoming multicast packets are passed to the 304 * kernel-level multicast forwarding function. 305 * The packet is returned (relatively) intact; if 306 * ip_mforward() returns a non-zero value, the packet 307 * must be discarded, else it may be accepted below. 308 * 309 * (The IP ident field is put in the same byte order 310 * as expected when ip_mforward() is called from 311 * ip_output().) 312 */ 313 ip->ip_id = htons(ip->ip_id); 314 if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 315 ipstat.ips_cantforward++; 316 m_freem(m); 317 goto next; 318 } 319 ip->ip_id = ntohs(ip->ip_id); 320 321 /* 322 * The process-level routing demon needs to receive 323 * all multicast IGMP packets, whether or not this 324 * host belongs to their destination groups. 325 */ 326 if (ip->ip_p == IPPROTO_IGMP) 327 goto ours; 328 ipstat.ips_forward++; 329 } 330 /* 331 * See if we belong to the destination multicast group on the 332 * arrival interface. 333 */ 334 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 335 if (inm == NULL) { 336 ipstat.ips_cantforward++; 337 m_freem(m); 338 goto next; 339 } 340 goto ours; 341 } 342 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 343 goto ours; 344 if (ip->ip_dst.s_addr == INADDR_ANY) 345 goto ours; 346 347 /* 348 * Not for us; forward if possible and desirable. 349 */ 350 if (ipforwarding == 0) { 351 ipstat.ips_cantforward++; 352 m_freem(m); 353 } else 354 ip_forward(m, 0); 355 goto next; 356 357 ours: 358 359 #ifdef IPACCT 360 /* 361 * If packet came to us we count it... 362 * This way we count all incoming packets which has 363 * not been forwarded... 364 * Do not convert ip_len to host byte order when 365 * counting,ppl already made it for us before.. 366 */ 367 ip_acct_cnt(ip,m->m_pkthdr.rcvif,ip_acct_chain,0); 368 #endif 369 370 /* 371 * If offset or IP_MF are set, must reassemble. 372 * Otherwise, nothing need be done. 373 * (We could look in the reassembly queue to see 374 * if the packet was previously fragmented, 375 * but it's not worth the time; just let them time out.) 376 */ 377 if (ip->ip_off &~ IP_DF) { 378 if (m->m_flags & M_EXT) { /* XXX */ 379 if ((m = m_pullup(m, sizeof (struct ip))) == 0) { 380 ipstat.ips_toosmall++; 381 goto next; 382 } 383 ip = mtod(m, struct ip *); 384 } 385 /* 386 * Look for queue of fragments 387 * of this datagram. 388 */ 389 for (fp = ipq.next; fp != &ipq; fp = fp->next) 390 if (ip->ip_id == fp->ipq_id && 391 ip->ip_src.s_addr == fp->ipq_src.s_addr && 392 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 393 ip->ip_p == fp->ipq_p) 394 goto found; 395 fp = 0; 396 found: 397 398 /* 399 * Adjust ip_len to not reflect header, 400 * set ip_mff if more fragments are expected, 401 * convert offset of this to bytes. 402 */ 403 ip->ip_len -= hlen; 404 ((struct ipasfrag *)ip)->ipf_mff &= ~1; 405 if (ip->ip_off & IP_MF) 406 ((struct ipasfrag *)ip)->ipf_mff |= 1; 407 ip->ip_off <<= 3; 408 409 /* 410 * If datagram marked as having more fragments 411 * or if this is not the first fragment, 412 * attempt reassembly; if it succeeds, proceed. 413 */ 414 if (((struct ipasfrag *)ip)->ipf_mff & 1 || ip->ip_off) { 415 ipstat.ips_fragments++; 416 ip = ip_reass((struct ipasfrag *)ip, fp); 417 if (ip == 0) 418 goto next; 419 ipstat.ips_reassembled++; 420 m = dtom(ip); 421 } else 422 if (fp) 423 ip_freef(fp); 424 } else 425 ip->ip_len -= hlen; 426 427 /* 428 * Switch out to protocol's input routine. 429 */ 430 ipstat.ips_delivered++; 431 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 432 goto next; 433 bad: 434 m_freem(m); 435 goto next; 436 } 437 438 /* 439 * Take incoming datagram fragment and try to 440 * reassemble it into whole datagram. If a chain for 441 * reassembly of this datagram already exists, then it 442 * is given as fp; otherwise have to make a chain. 443 */ 444 struct ip * 445 ip_reass(ip, fp) 446 register struct ipasfrag *ip; 447 register struct ipq *fp; 448 { 449 register struct mbuf *m = dtom(ip); 450 register struct ipasfrag *q; 451 struct mbuf *t; 452 int hlen = ip->ip_hl << 2; 453 int i, next; 454 455 /* 456 * Presence of header sizes in mbufs 457 * would confuse code below. 458 */ 459 m->m_data += hlen; 460 m->m_len -= hlen; 461 462 /* 463 * If first fragment to arrive, create a reassembly queue. 464 */ 465 if (fp == 0) { 466 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 467 goto dropfrag; 468 fp = mtod(t, struct ipq *); 469 insque(fp, &ipq); 470 fp->ipq_ttl = IPFRAGTTL; 471 fp->ipq_p = ip->ip_p; 472 fp->ipq_id = ip->ip_id; 473 fp->ipq_next = fp->ipq_prev = (struct ipasfrag *)fp; 474 fp->ipq_src = ((struct ip *)ip)->ip_src; 475 fp->ipq_dst = ((struct ip *)ip)->ip_dst; 476 q = (struct ipasfrag *)fp; 477 goto insert; 478 } 479 480 /* 481 * Find a segment which begins after this one does. 482 */ 483 for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) 484 if (q->ip_off > ip->ip_off) 485 break; 486 487 /* 488 * If there is a preceding segment, it may provide some of 489 * our data already. If so, drop the data from the incoming 490 * segment. If it provides all of our data, drop us. 491 */ 492 if (q->ipf_prev != (struct ipasfrag *)fp) { 493 i = q->ipf_prev->ip_off + q->ipf_prev->ip_len - ip->ip_off; 494 if (i > 0) { 495 if (i >= ip->ip_len) 496 goto dropfrag; 497 m_adj(dtom(ip), i); 498 ip->ip_off += i; 499 ip->ip_len -= i; 500 } 501 } 502 503 /* 504 * While we overlap succeeding segments trim them or, 505 * if they are completely covered, dequeue them. 506 */ 507 while (q != (struct ipasfrag *)fp && ip->ip_off + ip->ip_len > q->ip_off) { 508 i = (ip->ip_off + ip->ip_len) - q->ip_off; 509 if (i < q->ip_len) { 510 q->ip_len -= i; 511 q->ip_off += i; 512 m_adj(dtom(q), i); 513 break; 514 } 515 q = q->ipf_next; 516 m_freem(dtom(q->ipf_prev)); 517 ip_deq(q->ipf_prev); 518 } 519 520 insert: 521 /* 522 * Stick new segment in its place; 523 * check for complete reassembly. 524 */ 525 ip_enq(ip, q->ipf_prev); 526 next = 0; 527 for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) { 528 if (q->ip_off != next) 529 return (0); 530 next += q->ip_len; 531 } 532 if (q->ipf_prev->ipf_mff & 1) 533 return (0); 534 535 /* 536 * Reassembly is complete; concatenate fragments. 537 */ 538 q = fp->ipq_next; 539 m = dtom(q); 540 t = m->m_next; 541 m->m_next = 0; 542 m_cat(m, t); 543 q = q->ipf_next; 544 while (q != (struct ipasfrag *)fp) { 545 t = dtom(q); 546 q = q->ipf_next; 547 m_cat(m, t); 548 } 549 550 /* 551 * Create header for new ip packet by 552 * modifying header of first packet; 553 * dequeue and discard fragment reassembly header. 554 * Make header visible. 555 */ 556 ip = fp->ipq_next; 557 ip->ip_len = next; 558 ip->ipf_mff &= ~1; 559 ((struct ip *)ip)->ip_src = fp->ipq_src; 560 ((struct ip *)ip)->ip_dst = fp->ipq_dst; 561 remque(fp); 562 (void) m_free(dtom(fp)); 563 m = dtom(ip); 564 m->m_len += (ip->ip_hl << 2); 565 m->m_data -= (ip->ip_hl << 2); 566 /* some debugging cruft by sklower, below, will go away soon */ 567 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 568 register int plen = 0; 569 for (t = m; m; m = m->m_next) 570 plen += m->m_len; 571 t->m_pkthdr.len = plen; 572 } 573 return ((struct ip *)ip); 574 575 dropfrag: 576 ipstat.ips_fragdropped++; 577 m_freem(m); 578 return (0); 579 } 580 581 /* 582 * Free a fragment reassembly header and all 583 * associated datagrams. 584 */ 585 void 586 ip_freef(fp) 587 struct ipq *fp; 588 { 589 register struct ipasfrag *q, *p; 590 591 for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = p) { 592 p = q->ipf_next; 593 ip_deq(q); 594 m_freem(dtom(q)); 595 } 596 remque(fp); 597 (void) m_free(dtom(fp)); 598 } 599 600 /* 601 * Put an ip fragment on a reassembly chain. 602 * Like insque, but pointers in middle of structure. 603 */ 604 void 605 ip_enq(p, prev) 606 register struct ipasfrag *p, *prev; 607 { 608 609 p->ipf_prev = prev; 610 p->ipf_next = prev->ipf_next; 611 prev->ipf_next->ipf_prev = p; 612 prev->ipf_next = p; 613 } 614 615 /* 616 * To ip_enq as remque is to insque. 617 */ 618 void 619 ip_deq(p) 620 register struct ipasfrag *p; 621 { 622 623 p->ipf_prev->ipf_next = p->ipf_next; 624 p->ipf_next->ipf_prev = p->ipf_prev; 625 } 626 627 /* 628 * IP timer processing; 629 * if a timer expires on a reassembly 630 * queue, discard it. 631 */ 632 void 633 ip_slowtimo() 634 { 635 register struct ipq *fp; 636 int s = splnet(); 637 638 fp = ipq.next; 639 if (fp == 0) { 640 splx(s); 641 return; 642 } 643 while (fp != &ipq) { 644 --fp->ipq_ttl; 645 fp = fp->next; 646 if (fp->prev->ipq_ttl == 0) { 647 ipstat.ips_fragtimeout++; 648 ip_freef(fp->prev); 649 } 650 } 651 splx(s); 652 } 653 654 /* 655 * Drain off all datagram fragments. 656 */ 657 void 658 ip_drain() 659 { 660 661 while (ipq.next != &ipq) { 662 ipstat.ips_fragdropped++; 663 ip_freef(ipq.next); 664 } 665 } 666 667 /* 668 * Do option processing on a datagram, 669 * possibly discarding it if bad options are encountered, 670 * or forwarding it if source-routed. 671 * Returns 1 if packet has been forwarded/freed, 672 * 0 if the packet should be processed further. 673 */ 674 int 675 ip_dooptions(m) 676 struct mbuf *m; 677 { 678 register struct ip *ip = mtod(m, struct ip *); 679 register u_char *cp; 680 register struct ip_timestamp *ipt; 681 register struct in_ifaddr *ia; 682 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 683 struct in_addr *sin, dst; 684 n_time ntime; 685 686 dst = ip->ip_dst; 687 cp = (u_char *)(ip + 1); 688 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 689 for (; cnt > 0; cnt -= optlen, cp += optlen) { 690 opt = cp[IPOPT_OPTVAL]; 691 if (opt == IPOPT_EOL) 692 break; 693 if (opt == IPOPT_NOP) 694 optlen = 1; 695 else { 696 optlen = cp[IPOPT_OLEN]; 697 if (optlen <= 0 || optlen > cnt) { 698 code = &cp[IPOPT_OLEN] - (u_char *)ip; 699 goto bad; 700 } 701 } 702 switch (opt) { 703 704 default: 705 break; 706 707 /* 708 * Source routing with record. 709 * Find interface with current destination address. 710 * If none on this machine then drop if strictly routed, 711 * or do nothing if loosely routed. 712 * Record interface address and bring up next address 713 * component. If strictly routed make sure next 714 * address is on directly accessible net. 715 */ 716 case IPOPT_LSRR: 717 case IPOPT_SSRR: 718 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 719 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 720 goto bad; 721 } 722 ipaddr.sin_addr = ip->ip_dst; 723 ia = (struct in_ifaddr *) 724 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 725 if (ia == 0) { 726 if (opt == IPOPT_SSRR) { 727 type = ICMP_UNREACH; 728 code = ICMP_UNREACH_SRCFAIL; 729 goto bad; 730 } 731 /* 732 * Loose routing, and not at next destination 733 * yet; nothing to do except forward. 734 */ 735 break; 736 } 737 off--; /* 0 origin */ 738 if (off > optlen - sizeof(struct in_addr)) { 739 /* 740 * End of source route. Should be for us. 741 */ 742 save_rte(cp, ip->ip_src); 743 break; 744 } 745 /* 746 * locate outgoing interface 747 */ 748 bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr, 749 sizeof(ipaddr.sin_addr)); 750 if (opt == IPOPT_SSRR) { 751 #define INA struct in_ifaddr * 752 #define SA struct sockaddr * 753 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 754 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 755 } else 756 ia = ip_rtaddr(ipaddr.sin_addr); 757 if (ia == 0) { 758 type = ICMP_UNREACH; 759 code = ICMP_UNREACH_SRCFAIL; 760 goto bad; 761 } 762 ip->ip_dst = ipaddr.sin_addr; 763 bcopy((caddr_t)&(IA_SIN(ia)->sin_addr), 764 (caddr_t)(cp + off), sizeof(struct in_addr)); 765 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 766 /* 767 * Let ip_intr's mcast routing check handle mcast pkts 768 */ 769 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 770 break; 771 772 case IPOPT_RR: 773 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 774 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 775 goto bad; 776 } 777 /* 778 * If no space remains, ignore. 779 */ 780 off--; /* 0 origin */ 781 if (off > optlen - sizeof(struct in_addr)) 782 break; 783 bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr, 784 sizeof(ipaddr.sin_addr)); 785 /* 786 * locate outgoing interface; if we're the destination, 787 * use the incoming interface (should be same). 788 */ 789 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 790 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 791 type = ICMP_UNREACH; 792 code = ICMP_UNREACH_HOST; 793 goto bad; 794 } 795 bcopy((caddr_t)&(IA_SIN(ia)->sin_addr), 796 (caddr_t)(cp + off), sizeof(struct in_addr)); 797 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 798 break; 799 800 case IPOPT_TS: 801 code = cp - (u_char *)ip; 802 ipt = (struct ip_timestamp *)cp; 803 if (ipt->ipt_len < 5) 804 goto bad; 805 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (long)) { 806 if (++ipt->ipt_oflw == 0) 807 goto bad; 808 break; 809 } 810 sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); 811 switch (ipt->ipt_flg) { 812 813 case IPOPT_TS_TSONLY: 814 break; 815 816 case IPOPT_TS_TSANDADDR: 817 if (ipt->ipt_ptr + sizeof(n_time) + 818 sizeof(struct in_addr) > ipt->ipt_len) 819 goto bad; 820 ipaddr.sin_addr = dst; 821 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 822 m->m_pkthdr.rcvif); 823 if (ia == 0) 824 continue; 825 bcopy((caddr_t)&IA_SIN(ia)->sin_addr, 826 (caddr_t)sin, sizeof(struct in_addr)); 827 ipt->ipt_ptr += sizeof(struct in_addr); 828 break; 829 830 case IPOPT_TS_PRESPEC: 831 if (ipt->ipt_ptr + sizeof(n_time) + 832 sizeof(struct in_addr) > ipt->ipt_len) 833 goto bad; 834 bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr, 835 sizeof(struct in_addr)); 836 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 837 continue; 838 ipt->ipt_ptr += sizeof(struct in_addr); 839 break; 840 841 default: 842 goto bad; 843 } 844 ntime = iptime(); 845 bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1, 846 sizeof(n_time)); 847 ipt->ipt_ptr += sizeof(n_time); 848 } 849 } 850 if (forward) { 851 ip_forward(m, 1); 852 return (1); 853 } 854 return (0); 855 bad: 856 ip->ip_len -= ip->ip_hl << 2; /* XXX icmp_error adds in hdr length */ 857 icmp_error(m, type, code, 0, 0); 858 ipstat.ips_badoptions++; 859 return (1); 860 } 861 862 /* 863 * Given address of next destination (final or next hop), 864 * return internet address info of interface to be used to get there. 865 */ 866 struct in_ifaddr * 867 ip_rtaddr(dst) 868 struct in_addr dst; 869 { 870 register struct sockaddr_in *sin; 871 872 sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; 873 874 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 875 if (ipforward_rt.ro_rt) { 876 RTFREE(ipforward_rt.ro_rt); 877 ipforward_rt.ro_rt = 0; 878 } 879 sin->sin_family = AF_INET; 880 sin->sin_len = sizeof(*sin); 881 sin->sin_addr = dst; 882 883 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 884 } 885 if (ipforward_rt.ro_rt == 0) 886 return ((struct in_ifaddr *)0); 887 return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); 888 } 889 890 /* 891 * Save incoming source route for use in replies, 892 * to be picked up later by ip_srcroute if the receiver is interested. 893 */ 894 void 895 save_rte(option, dst) 896 u_char *option; 897 struct in_addr dst; 898 { 899 unsigned olen; 900 901 olen = option[IPOPT_OLEN]; 902 #ifdef DIAGNOSTIC 903 if (ipprintfs) 904 printf("save_rte: olen %d\n", olen); 905 #endif 906 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 907 return; 908 bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen); 909 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 910 ip_srcrt.dst = dst; 911 } 912 913 /* 914 * Retrieve incoming source route for use in replies, 915 * in the same form used by setsockopt. 916 * The first hop is placed before the options, will be removed later. 917 */ 918 struct mbuf * 919 ip_srcroute() 920 { 921 register struct in_addr *p, *q; 922 register struct mbuf *m; 923 924 if (ip_nhops == 0) 925 return ((struct mbuf *)0); 926 m = m_get(M_DONTWAIT, MT_SOOPTS); 927 if (m == 0) 928 return ((struct mbuf *)0); 929 930 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 931 932 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 933 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 934 OPTSIZ; 935 #ifdef DIAGNOSTIC 936 if (ipprintfs) 937 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 938 #endif 939 940 /* 941 * First save first hop for return route 942 */ 943 p = &ip_srcrt.route[ip_nhops - 1]; 944 *(mtod(m, struct in_addr *)) = *p--; 945 #ifdef DIAGNOSTIC 946 if (ipprintfs) 947 printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr)); 948 #endif 949 950 /* 951 * Copy option fields and padding (nop) to mbuf. 952 */ 953 ip_srcrt.nop = IPOPT_NOP; 954 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 955 bcopy((caddr_t)&ip_srcrt.nop, 956 mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ); 957 q = (struct in_addr *)(mtod(m, caddr_t) + 958 sizeof(struct in_addr) + OPTSIZ); 959 #undef OPTSIZ 960 /* 961 * Record return path as an IP source route, 962 * reversing the path (pointers are now aligned). 963 */ 964 while (p >= ip_srcrt.route) { 965 #ifdef DIAGNOSTIC 966 if (ipprintfs) 967 printf(" %lx", ntohl(q->s_addr)); 968 #endif 969 *q++ = *p--; 970 } 971 /* 972 * Last hop goes to final destination. 973 */ 974 *q = ip_srcrt.dst; 975 #ifdef DIAGNOSTIC 976 if (ipprintfs) 977 printf(" %lx\n", ntohl(q->s_addr)); 978 #endif 979 return (m); 980 } 981 982 /* 983 * Strip out IP options, at higher 984 * level protocol in the kernel. 985 * Second argument is buffer to which options 986 * will be moved, and return value is their length. 987 * XXX should be deleted; last arg currently ignored. 988 */ 989 void 990 ip_stripoptions(m, mopt) 991 register struct mbuf *m; 992 struct mbuf *mopt; 993 { 994 register int i; 995 struct ip *ip = mtod(m, struct ip *); 996 register caddr_t opts; 997 int olen; 998 999 olen = (ip->ip_hl<<2) - sizeof (struct ip); 1000 opts = (caddr_t)(ip + 1); 1001 i = m->m_len - (sizeof (struct ip) + olen); 1002 bcopy(opts + olen, opts, (unsigned)i); 1003 m->m_len -= olen; 1004 if (m->m_flags & M_PKTHDR) 1005 m->m_pkthdr.len -= olen; 1006 ip->ip_hl = sizeof(struct ip) >> 2; 1007 } 1008 1009 u_char inetctlerrmap[PRC_NCMDS] = { 1010 0, 0, 0, 0, 1011 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1012 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1013 EMSGSIZE, EHOSTUNREACH, 0, 0, 1014 0, 0, 0, 0, 1015 ENOPROTOOPT 1016 }; 1017 1018 /* 1019 * Forward a packet. If some error occurs return the sender 1020 * an icmp packet. Note we can't always generate a meaningful 1021 * icmp message because icmp doesn't have a large enough repertoire 1022 * of codes and types. 1023 * 1024 * If not forwarding, just drop the packet. This could be confusing 1025 * if ipforwarding was zero but some routing protocol was advancing 1026 * us as a gateway to somewhere. However, we must let the routing 1027 * protocol deal with that. 1028 * 1029 * The srcrt parameter indicates whether the packet is being forwarded 1030 * via a source route. 1031 */ 1032 void 1033 ip_forward(m, srcrt) 1034 struct mbuf *m; 1035 int srcrt; 1036 { 1037 register struct ip *ip = mtod(m, struct ip *); 1038 register struct sockaddr_in *sin; 1039 register struct rtentry *rt; 1040 int error, type = 0, code = 0; 1041 struct mbuf *mcopy; 1042 n_long dest; 1043 struct ifnet *destifp; 1044 1045 dest = 0; 1046 #ifdef DIAGNOSTIC 1047 if (ipprintfs) 1048 printf("forward: src %lx dst %lx ttl %x\n", 1049 ip->ip_src.s_addr, ip->ip_dst.s_addr, ip->ip_ttl); 1050 #endif 1051 1052 #ifdef IPFIREWALL 1053 if ( ((char *)&(ip->ip_dst.s_addr))[0] != 127 1054 && !ip_fw_chk(ip, m->m_pkthdr.rcvif, ip_fw_fwd_chain) ) { 1055 ipstat.ips_cantforward++; 1056 m_freem(m); 1057 return; 1058 } 1059 #endif 1060 1061 if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) { 1062 ipstat.ips_cantforward++; 1063 m_freem(m); 1064 return; 1065 } 1066 HTONS(ip->ip_id); 1067 if (ip->ip_ttl <= IPTTLDEC) { 1068 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1069 return; 1070 } 1071 ip->ip_ttl -= IPTTLDEC; 1072 1073 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1074 if ((rt = ipforward_rt.ro_rt) == 0 || 1075 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1076 if (ipforward_rt.ro_rt) { 1077 RTFREE(ipforward_rt.ro_rt); 1078 ipforward_rt.ro_rt = 0; 1079 } 1080 sin->sin_family = AF_INET; 1081 sin->sin_len = sizeof(*sin); 1082 sin->sin_addr = ip->ip_dst; 1083 1084 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1085 if (ipforward_rt.ro_rt == 0) { 1086 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1087 return; 1088 } 1089 rt = ipforward_rt.ro_rt; 1090 } 1091 1092 /* 1093 * Save at most 64 bytes of the packet in case 1094 * we need to generate an ICMP message to the src. 1095 */ 1096 mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); 1097 1098 #ifdef bogus 1099 #ifdef GATEWAY 1100 ip_ifmatrix[rt->rt_ifp->if_index + 1101 if_index * m->m_pkthdr.rcvif->if_index]++; 1102 #endif 1103 #endif 1104 /* 1105 * If forwarding packet using same interface that it came in on, 1106 * perhaps should send a redirect to sender to shortcut a hop. 1107 * Only send redirect if source is sending directly to us, 1108 * and if packet was not source routed (or has any options). 1109 * Also, don't send redirect if forwarding using a default route 1110 * or a route modified by a redirect. 1111 */ 1112 #define satosin(sa) ((struct sockaddr_in *)(sa)) 1113 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1114 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1115 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1116 ipsendredirects && !srcrt) { 1117 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1118 u_long src = ntohl(ip->ip_src.s_addr); 1119 1120 if (RTA(rt) && 1121 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1122 if (rt->rt_flags & RTF_GATEWAY) 1123 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1124 else 1125 dest = ip->ip_dst.s_addr; 1126 /* Router requirements says to only send host redirects */ 1127 type = ICMP_REDIRECT; 1128 code = ICMP_REDIRECT_HOST; 1129 #ifdef DIAGNOSTIC 1130 if (ipprintfs) 1131 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1132 #endif 1133 } 1134 } 1135 1136 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, IP_FORWARDING 1137 #ifdef DIRECTED_BROADCAST 1138 | IP_ALLOWBROADCAST 1139 #endif 1140 , 0); 1141 if (error) 1142 ipstat.ips_cantforward++; 1143 else { 1144 ipstat.ips_forward++; 1145 if (type) 1146 ipstat.ips_redirectsent++; 1147 else { 1148 if (mcopy) 1149 m_freem(mcopy); 1150 return; 1151 } 1152 } 1153 if (mcopy == NULL) 1154 return; 1155 destifp = NULL; 1156 1157 switch (error) { 1158 1159 case 0: /* forwarded, but need redirect */ 1160 /* type, code set above */ 1161 break; 1162 1163 case ENETUNREACH: /* shouldn't happen, checked above */ 1164 case EHOSTUNREACH: 1165 case ENETDOWN: 1166 case EHOSTDOWN: 1167 default: 1168 type = ICMP_UNREACH; 1169 code = ICMP_UNREACH_HOST; 1170 break; 1171 1172 case EMSGSIZE: 1173 type = ICMP_UNREACH; 1174 code = ICMP_UNREACH_NEEDFRAG; 1175 if (ipforward_rt.ro_rt) 1176 destifp = ipforward_rt.ro_rt->rt_ifp; 1177 ipstat.ips_cantfrag++; 1178 break; 1179 1180 case ENOBUFS: 1181 type = ICMP_SOURCEQUENCH; 1182 code = 0; 1183 break; 1184 } 1185 icmp_error(mcopy, type, code, dest, destifp); 1186 } 1187 1188 int 1189 ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 1190 int *name; 1191 u_int namelen; 1192 void *oldp; 1193 size_t *oldlenp; 1194 void *newp; 1195 size_t newlen; 1196 { 1197 extern int rtq_reallyold; /* XXX */ 1198 1199 /* All sysctl names at this level are terminal. */ 1200 if (namelen != 1) 1201 return (ENOTDIR); 1202 1203 switch (name[0]) { 1204 case IPCTL_FORWARDING: 1205 return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding)); 1206 case IPCTL_SENDREDIRECTS: 1207 return (sysctl_int(oldp, oldlenp, newp, newlen, 1208 &ipsendredirects)); 1209 case IPCTL_DEFTTL: 1210 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl)); 1211 #ifdef notyet 1212 case IPCTL_DEFMTU: 1213 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu)); 1214 #endif 1215 case IPCTL_RTEXPIRE: 1216 return (sysctl_int(oldp, oldlenp, newp, newlen, &rtq_reallyold)); 1217 default: 1218 return (EOPNOTSUPP); 1219 } 1220 /* NOTREACHED */ 1221 } 1222 1223 int 1224 ip_rsvp_init(struct socket *so) 1225 { 1226 if (so->so_type != SOCK_RAW || 1227 so->so_proto->pr_protocol != IPPROTO_RSVP) 1228 return EOPNOTSUPP; 1229 1230 if (ip_rsvpd != NULL) 1231 return EADDRINUSE; 1232 1233 ip_rsvpd = so; 1234 1235 return 0; 1236 } 1237 1238 int 1239 ip_rsvp_done(void) 1240 { 1241 ip_rsvpd = NULL; 1242 return 0; 1243 } 1244