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 1.103 1998/10/27 09:11:41 dfr 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 79 int rsvp_on = 0; 80 static int ip_rsvp_on; 81 struct socket *ip_rsvpd; 82 83 int ipforwarding = 0; 84 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 85 &ipforwarding, 0, ""); 86 87 static int ipsendredirects = 1; /* XXX */ 88 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 89 &ipsendredirects, 0, ""); 90 91 int ip_defttl = IPDEFTTL; 92 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 93 &ip_defttl, 0, ""); 94 95 static int ip_dosourceroute = 0; 96 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 97 &ip_dosourceroute, 0, ""); 98 99 static int ip_acceptsourceroute = 0; 100 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 101 CTLFLAG_RW, &ip_acceptsourceroute, 0, ""); 102 #ifdef DIAGNOSTIC 103 static int ipprintfs = 0; 104 #endif 105 106 extern struct domain inetdomain; 107 extern struct protosw inetsw[]; 108 u_char ip_protox[IPPROTO_MAX]; 109 static int ipqmaxlen = IFQ_MAXLEN; 110 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 111 struct ifqueue ipintrq; 112 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RD, 113 &ipintrq.ifq_maxlen, 0, ""); 114 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 115 &ipintrq.ifq_drops, 0, ""); 116 117 struct ipstat ipstat; 118 SYSCTL_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) 127 128 static struct ipq ipq[IPREASS_NHASH]; 129 static int nipq = 0; /* total # of reass queues */ 130 static int maxnipq; 131 132 #ifdef IPCTL_DEFMTU 133 SYSCTL_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 145 146 #include <netinet/ip_fw.h> 147 148 /* Firewall hooks */ 149 ip_fw_chk_t *ip_fw_chk_ptr; 150 ip_fw_ctl_t *ip_fw_ctl_ptr; 151 152 /* IP Network Address Translation (NAT) hooks */ 153 ip_nat_t *ip_nat_ptr; 154 ip_nat_ctl_t *ip_nat_ctl_ptr; 155 #endif 156 157 #if defined(IPFILTER_LKM) || defined(IPFILTER) 158 int iplattach __P((void)); 159 int (*fr_checkp) __P((struct ip *, int, struct ifnet *, int, struct mbuf **)) = NULL; 160 #endif 161 162 163 /* 164 * We need to save the IP options in case a protocol wants to respond 165 * to an incoming packet over the same route if the packet got here 166 * using IP source routing. This allows connection establishment and 167 * maintenance when the remote end is on a network that is not known 168 * to us. 169 */ 170 static int ip_nhops = 0; 171 static struct ip_srcrt { 172 struct in_addr dst; /* final destination */ 173 char nop; /* one NOP to align */ 174 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 175 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 176 } ip_srcrt; 177 178 #ifdef IPDIVERT 179 /* 180 * Shared variable between ip_input() and ip_reass() to communicate 181 * about which packets, once assembled from fragments, get diverted, 182 * and to which port. 183 */ 184 static u_short frag_divert_port; 185 #endif 186 187 struct sockaddr_in *ip_fw_fwd_addr; 188 189 static void save_rte __P((u_char *, struct in_addr)); 190 static int ip_dooptions __P((struct mbuf *)); 191 static void ip_forward __P((struct mbuf *, int)); 192 static void ip_freef __P((struct ipq *)); 193 static struct ip * 194 ip_reass __P((struct mbuf *, struct ipq *, struct ipq *)); 195 static struct in_ifaddr * 196 ip_rtaddr __P((struct in_addr)); 197 static void ipintr __P((void)); 198 /* 199 * IP initialization: fill in IP protocol switch table. 200 * All protocols not implemented in kernel go to raw IP protocol handler. 201 */ 202 void 203 ip_init() 204 { 205 register struct protosw *pr; 206 register int i; 207 208 TAILQ_INIT(&in_ifaddrhead); 209 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 210 if (pr == 0) 211 panic("ip_init"); 212 for (i = 0; i < IPPROTO_MAX; i++) 213 ip_protox[i] = pr - inetsw; 214 for (pr = inetdomain.dom_protosw; 215 pr < inetdomain.dom_protoswNPROTOSW; pr++) 216 if (pr->pr_domain->dom_family == PF_INET && 217 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 218 ip_protox[pr->pr_protocol] = pr - inetsw; 219 220 for (i = 0; i < IPREASS_NHASH; i++) 221 ipq[i].next = ipq[i].prev = &ipq[i]; 222 223 maxnipq = nmbclusters/4; 224 225 ip_id = time_second & 0xffff; 226 ipintrq.ifq_maxlen = ipqmaxlen; 227 #ifdef IPNAT 228 ip_nat_init(); 229 #endif 230 #ifdef IPFILTER 231 iplattach(); 232 #endif 233 234 } 235 236 static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 237 static struct route ipforward_rt; 238 239 /* 240 * Ip input routine. Checksum and byte swap header. If fragmented 241 * try to reassemble. Process options. Pass to next level. 242 */ 243 void 244 ip_input(struct mbuf *m) 245 { 246 struct ip *ip; 247 struct ipq *fp; 248 struct ipqent *ipqe; 249 struct in_ifaddr *ia; 250 int i, hlen, mff; 251 u_short sum; 252 253 #ifdef DIAGNOSTIC 254 if (m == NULL || (m->m_flags & M_PKTHDR) == 0) 255 panic("ip_input no HDR"); 256 #endif 257 /* 258 * If no IP addresses have been set yet but the interfaces 259 * are receiving, can't do anything with incoming packets yet. 260 * XXX This is broken! We should be able to receive broadcasts 261 * and multicasts even without any local addresses configured. 262 */ 263 if (TAILQ_EMPTY(&in_ifaddrhead)) 264 goto bad; 265 ipstat.ips_total++; 266 267 if (m->m_pkthdr.len < sizeof(struct ip)) 268 goto tooshort; 269 270 if (m->m_len < sizeof (struct ip) && 271 (m = m_pullup(m, sizeof (struct ip))) == 0) { 272 ipstat.ips_toosmall++; 273 return; 274 } 275 ip = mtod(m, struct ip *); 276 277 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 278 ipstat.ips_badvers++; 279 goto bad; 280 } 281 282 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 283 if (hlen < sizeof(struct ip)) { /* minimum header length */ 284 ipstat.ips_badhlen++; 285 goto bad; 286 } 287 if (hlen > m->m_len) { 288 if ((m = m_pullup(m, hlen)) == 0) { 289 ipstat.ips_badhlen++; 290 return; 291 } 292 ip = mtod(m, struct ip *); 293 } 294 if (hlen == sizeof(struct ip)) { 295 sum = in_cksum_hdr(ip); 296 } else { 297 sum = in_cksum(m, hlen); 298 } 299 if (sum) { 300 ipstat.ips_badsum++; 301 goto bad; 302 } 303 304 /* 305 * Convert fields to host representation. 306 */ 307 NTOHS(ip->ip_len); 308 if (ip->ip_len < hlen) { 309 ipstat.ips_badlen++; 310 goto bad; 311 } 312 NTOHS(ip->ip_id); 313 NTOHS(ip->ip_off); 314 315 /* 316 * Check that the amount of data in the buffers 317 * is as at least much as the IP header would have us expect. 318 * Trim mbufs if longer than we expect. 319 * Drop packet if shorter than we expect. 320 */ 321 if (m->m_pkthdr.len < ip->ip_len) { 322 tooshort: 323 ipstat.ips_tooshort++; 324 goto bad; 325 } 326 if (m->m_pkthdr.len > ip->ip_len) { 327 if (m->m_len == m->m_pkthdr.len) { 328 m->m_len = ip->ip_len; 329 m->m_pkthdr.len = ip->ip_len; 330 } else 331 m_adj(m, ip->ip_len - m->m_pkthdr.len); 332 } 333 /* 334 * IpHack's section. 335 * Right now when no processing on packet has done 336 * and it is still fresh out of network we do our black 337 * deals with it. 338 * - Firewall: deny/allow/divert 339 * - Xlate: translate packet's addr/port (NAT). 340 * - Wrap: fake packet's addr/port <unimpl.> 341 * - Encapsulate: put it in another IP and send out. <unimp.> 342 */ 343 #if defined(IPFILTER) || defined(IPFILTER_LKM) 344 /* 345 * Check if we want to allow this packet to be processed. 346 * Consider it to be bad if not. 347 */ 348 if (fr_checkp) { 349 struct mbuf *m1 = m; 350 351 if ((*fr_checkp)(ip, hlen, m->m_pkthdr.rcvif, 0, &m1) || !m1) 352 return; 353 ip = mtod(m = m1, struct ip *); 354 } 355 #endif 356 #ifdef COMPAT_IPFW 357 if (ip_fw_chk_ptr) { 358 u_int16_t port; 359 360 #ifdef IPFIREWALL_FORWARD 361 /* 362 * If we've been forwarded from the output side, then 363 * skip the firewall a second time 364 */ 365 if (ip_fw_fwd_addr) 366 goto ours; 367 #endif /* IPFIREWALL_FORWARD */ 368 #ifdef IPDIVERT 369 port = (*ip_fw_chk_ptr)(&ip, hlen, NULL, &ip_divert_cookie, 370 &m, &ip_fw_fwd_addr); 371 if (port) { 372 /* Divert packet */ 373 frag_divert_port = port; 374 goto ours; 375 } 376 #else /* !DIVERT */ 377 /* 378 * If ipfw says divert, we have to just drop packet 379 * Use port as a dummy argument. 380 */ 381 port = 0; 382 if ((*ip_fw_chk_ptr)(&ip, hlen, NULL, &port, 383 &m, &ip_fw_fwd_addr)) { 384 m_freem(m); 385 m = NULL; 386 } 387 #endif /* !DIVERT */ 388 if (!m) 389 return; 390 } 391 392 if (ip_nat_ptr && !(*ip_nat_ptr)(&ip, &m, m->m_pkthdr.rcvif, IP_NAT_IN)) 393 return; 394 #endif /* !COMPAT_IPFW */ 395 396 /* 397 * Process options and, if not destined for us, 398 * ship it on. ip_dooptions returns 1 when an 399 * error was detected (causing an icmp message 400 * to be sent and the original packet to be freed). 401 */ 402 ip_nhops = 0; /* for source routed packets */ 403 if (hlen > sizeof (struct ip) && ip_dooptions(m)) 404 return; 405 406 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 407 * matter if it is destined to another node, or whether it is 408 * a multicast one, RSVP wants it! and prevents it from being forwarded 409 * anywhere else. Also checks if the rsvp daemon is running before 410 * grabbing the packet. 411 */ 412 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 413 goto ours; 414 415 /* 416 * Check our list of addresses, to see if the packet is for us. 417 */ 418 for (ia = TAILQ_FIRST(&in_ifaddrhead); ia; 419 ia = TAILQ_NEXT(ia, ia_link)) { 420 #define satosin(sa) ((struct sockaddr_in *)(sa)) 421 422 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 423 goto ours; 424 #ifdef BOOTP_COMPAT 425 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 426 goto ours; 427 #endif 428 #ifdef IPFIREWALL_FORWARD 429 /* 430 * If the addr to forward to is one of ours, we pretend to 431 * be the destination for this packet. 432 */ 433 if (ip_fw_fwd_addr != NULL && 434 IA_SIN(ia)->sin_addr.s_addr == 435 ip_fw_fwd_addr->sin_addr.s_addr) 436 goto ours; 437 #endif 438 if (ia->ia_ifp && ia->ia_ifp->if_flags & IFF_BROADCAST) { 439 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 440 ip->ip_dst.s_addr) 441 goto ours; 442 if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr) 443 goto ours; 444 } 445 } 446 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 447 struct in_multi *inm; 448 if (ip_mrouter) { 449 /* 450 * If we are acting as a multicast router, all 451 * incoming multicast packets are passed to the 452 * kernel-level multicast forwarding function. 453 * The packet is returned (relatively) intact; if 454 * ip_mforward() returns a non-zero value, the packet 455 * must be discarded, else it may be accepted below. 456 * 457 * (The IP ident field is put in the same byte order 458 * as expected when ip_mforward() is called from 459 * ip_output().) 460 */ 461 ip->ip_id = htons(ip->ip_id); 462 if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 463 ipstat.ips_cantforward++; 464 m_freem(m); 465 return; 466 } 467 ip->ip_id = ntohs(ip->ip_id); 468 469 /* 470 * The process-level routing demon needs to receive 471 * all multicast IGMP packets, whether or not this 472 * host belongs to their destination groups. 473 */ 474 if (ip->ip_p == IPPROTO_IGMP) 475 goto ours; 476 ipstat.ips_forward++; 477 } 478 /* 479 * See if we belong to the destination multicast group on the 480 * arrival interface. 481 */ 482 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 483 if (inm == NULL) { 484 ipstat.ips_notmember++; 485 m_freem(m); 486 return; 487 } 488 goto ours; 489 } 490 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 491 goto ours; 492 if (ip->ip_dst.s_addr == INADDR_ANY) 493 goto ours; 494 495 /* 496 * Not for us; forward if possible and desirable. 497 */ 498 if (ipforwarding == 0) { 499 ipstat.ips_cantforward++; 500 m_freem(m); 501 } else 502 ip_forward(m, 0); 503 return; 504 505 ours: 506 507 /* 508 * If offset or IP_MF are set, must reassemble. 509 * Otherwise, nothing need be done. 510 * (We could look in the reassembly queue to see 511 * if the packet was previously fragmented, 512 * but it's not worth the time; just let them time out.) 513 */ 514 if (ip->ip_off & (IP_MF | IP_OFFMASK | IP_RF)) { 515 if (m->m_flags & M_EXT) { /* XXX */ 516 if ((m = m_pullup(m, sizeof (struct ip))) == 0) { 517 ipstat.ips_toosmall++; 518 #ifdef IPDIVERT 519 frag_divert_port = 0; 520 ip_divert_cookie = 0; 521 #endif 522 return; 523 } 524 ip = mtod(m, struct ip *); 525 } 526 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 527 /* 528 * Look for queue of fragments 529 * of this datagram. 530 */ 531 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 532 if (ip->ip_id == fp->ipq_id && 533 ip->ip_src.s_addr == fp->ipq_src.s_addr && 534 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 535 ip->ip_p == fp->ipq_p) 536 goto found; 537 538 fp = 0; 539 540 /* check if there's a place for the new queue */ 541 if (nipq > maxnipq) { 542 /* 543 * drop something from the tail of the current queue 544 * before proceeding further 545 */ 546 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 547 for (i = 0; i < IPREASS_NHASH; i++) { 548 if (ipq[i].prev != &ipq[i]) { 549 ip_freef(ipq[i].prev); 550 break; 551 } 552 } 553 } else 554 ip_freef(ipq[sum].prev); 555 } 556 found: 557 /* 558 * Adjust ip_len to not reflect header, 559 * set ip_mff if more fragments are expected, 560 * convert offset of this to bytes. 561 */ 562 ip->ip_len -= hlen; 563 mff = (ip->ip_off & IP_MF) != 0; 564 if (mff) { 565 /* 566 * Make sure that fragments have a data length 567 * that's a non-zero multiple of 8 bytes. 568 */ 569 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 570 ipstat.ips_toosmall++; /* XXX */ 571 goto bad; 572 } 573 m->m_flags |= M_FRAG; 574 } 575 ip->ip_off <<= 3; 576 577 /* 578 * If datagram marked as having more fragments 579 * or if this is not the first fragment, 580 * attempt reassembly; if it succeeds, proceed. 581 */ 582 if (mff || ip->ip_off) { 583 ipstat.ips_fragments++; 584 m->m_pkthdr.header = ip; 585 ip = ip_reass(m, fp, &ipq[sum]); 586 if (ip == 0) { 587 #ifdef IPFIREWALL_FORWARD 588 ip_fw_fwd_addr = NULL; 589 #endif 590 return; 591 } 592 /* Get the length of the reassembled packets header */ 593 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 594 ipstat.ips_reassembled++; 595 m = dtom(ip); 596 #ifdef IPDIVERT 597 if (frag_divert_port) { 598 ip->ip_len += hlen; 599 HTONS(ip->ip_len); 600 HTONS(ip->ip_off); 601 HTONS(ip->ip_id); 602 ip->ip_sum = 0; 603 ip->ip_sum = in_cksum_hdr(ip); 604 NTOHS(ip->ip_id); 605 NTOHS(ip->ip_off); 606 NTOHS(ip->ip_len); 607 ip->ip_len -= hlen; 608 } 609 #endif 610 } else 611 if (fp) 612 ip_freef(fp); 613 } else 614 ip->ip_len -= hlen; 615 616 #ifdef IPDIVERT 617 /* 618 * Divert reassembled packets to the divert protocol if required 619 * If divert port is null then cookie should be too, 620 * so we shouldn't need to clear them here. Assume ip_divert does so. 621 */ 622 if (frag_divert_port) { 623 ipstat.ips_delivered++; 624 ip_divert_port = frag_divert_port; 625 frag_divert_port = 0; 626 (*inetsw[ip_protox[IPPROTO_DIVERT]].pr_input)(m, hlen); 627 return; 628 } 629 630 /* Don't let packets divert themselves */ 631 if (ip->ip_p == IPPROTO_DIVERT) { 632 ipstat.ips_noproto++; 633 goto bad; 634 } 635 636 #endif 637 638 /* 639 * Switch out to protocol's input routine. 640 */ 641 ipstat.ips_delivered++; 642 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 643 #ifdef IPFIREWALL_FORWARD 644 ip_fw_fwd_addr = NULL; /* tcp needed it */ 645 #endif 646 return; 647 bad: 648 #ifdef IPFIREWALL_FORWARD 649 ip_fw_fwd_addr = NULL; 650 #endif 651 m_freem(m); 652 } 653 654 /* 655 * IP software interrupt routine - to go away sometime soon 656 */ 657 static void 658 ipintr(void) 659 { 660 int s; 661 struct mbuf *m; 662 663 while(1) { 664 s = splimp(); 665 IF_DEQUEUE(&ipintrq, m); 666 splx(s); 667 if (m == 0) 668 return; 669 ip_input(m); 670 } 671 } 672 673 NETISR_SET(NETISR_IP, ipintr); 674 675 /* 676 * Take incoming datagram fragment and try to 677 * reassemble it into whole datagram. If a chain for 678 * reassembly of this datagram already exists, then it 679 * is given as fp; otherwise have to make a chain. 680 */ 681 static struct ip * 682 ip_reass(m, fp, where) 683 register struct mbuf *m; 684 register struct ipq *fp; 685 struct ipq *where; 686 { 687 struct ip *ip = mtod(m, struct ip *); 688 register struct mbuf *p = 0, *q, *nq; 689 struct mbuf *t; 690 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 691 int i, next; 692 693 /* 694 * Presence of header sizes in mbufs 695 * would confuse code below. 696 */ 697 m->m_data += hlen; 698 m->m_len -= hlen; 699 700 /* 701 * If first fragment to arrive, create a reassembly queue. 702 */ 703 if (fp == 0) { 704 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 705 goto dropfrag; 706 fp = mtod(t, struct ipq *); 707 insque(fp, where); 708 nipq++; 709 fp->ipq_ttl = IPFRAGTTL; 710 fp->ipq_p = ip->ip_p; 711 fp->ipq_id = ip->ip_id; 712 fp->ipq_src = ip->ip_src; 713 fp->ipq_dst = ip->ip_dst; 714 fp->ipq_frags = m; 715 m->m_nextpkt = NULL; 716 #ifdef IPDIVERT 717 fp->ipq_divert = 0; 718 fp->ipq_div_cookie = 0; 719 #endif 720 goto inserted; 721 } 722 723 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 724 725 /* 726 * Find a segment which begins after this one does. 727 */ 728 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 729 if (GETIP(q)->ip_off > ip->ip_off) 730 break; 731 732 /* 733 * If there is a preceding segment, it may provide some of 734 * our data already. If so, drop the data from the incoming 735 * segment. If it provides all of our data, drop us, otherwise 736 * stick new segment in the proper place. 737 */ 738 if (p) { 739 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 740 if (i > 0) { 741 if (i >= ip->ip_len) 742 goto dropfrag; 743 m_adj(dtom(ip), i); 744 ip->ip_off += i; 745 ip->ip_len -= i; 746 } 747 m->m_nextpkt = p->m_nextpkt; 748 p->m_nextpkt = m; 749 } else { 750 m->m_nextpkt = fp->ipq_frags; 751 fp->ipq_frags = m; 752 } 753 754 /* 755 * While we overlap succeeding segments trim them or, 756 * if they are completely covered, dequeue them. 757 */ 758 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 759 q = nq) { 760 i = (ip->ip_off + ip->ip_len) - 761 GETIP(q)->ip_off; 762 if (i < GETIP(q)->ip_len) { 763 GETIP(q)->ip_len -= i; 764 GETIP(q)->ip_off += i; 765 m_adj(q, i); 766 break; 767 } 768 nq = q->m_nextpkt; 769 m->m_nextpkt = nq; 770 m_freem(q); 771 } 772 773 inserted: 774 775 #ifdef IPDIVERT 776 /* 777 * Any fragment diverting causes the whole packet to divert 778 */ 779 if (frag_divert_port) { 780 fp->ipq_divert = frag_divert_port; 781 fp->ipq_div_cookie = ip_divert_cookie; 782 } 783 frag_divert_port = 0; 784 ip_divert_cookie = 0; 785 #endif 786 787 /* 788 * Check for complete reassembly. 789 */ 790 next = 0; 791 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 792 if (GETIP(q)->ip_off != next) 793 return (0); 794 next += GETIP(q)->ip_len; 795 } 796 /* Make sure the last packet didn't have the IP_MF flag */ 797 if (p->m_flags & M_FRAG) 798 return (0); 799 800 /* 801 * Reassembly is complete. Make sure the packet is a sane size. 802 */ 803 q = fp->ipq_frags; 804 ip = GETIP(q); 805 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 806 ipstat.ips_toolong++; 807 ip_freef(fp); 808 return (0); 809 } 810 811 /* 812 * Concatenate fragments. 813 */ 814 m = q; 815 t = m->m_next; 816 m->m_next = 0; 817 m_cat(m, t); 818 nq = q->m_nextpkt; 819 q->m_nextpkt = 0; 820 for (q = nq; q != NULL; q = nq) { 821 nq = q->m_nextpkt; 822 q->m_nextpkt = NULL; 823 m_cat(m, q); 824 } 825 826 #ifdef IPDIVERT 827 /* 828 * extract divert port for packet, if any 829 */ 830 frag_divert_port = fp->ipq_divert; 831 ip_divert_cookie = fp->ipq_div_cookie; 832 #endif 833 834 /* 835 * Create header for new ip packet by 836 * modifying header of first packet; 837 * dequeue and discard fragment reassembly header. 838 * Make header visible. 839 */ 840 ip->ip_len = next; 841 ip->ip_src = fp->ipq_src; 842 ip->ip_dst = fp->ipq_dst; 843 remque(fp); 844 nipq--; 845 (void) m_free(dtom(fp)); 846 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 847 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 848 /* some debugging cruft by sklower, below, will go away soon */ 849 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 850 register int plen = 0; 851 for (t = m; m; m = m->m_next) 852 plen += m->m_len; 853 t->m_pkthdr.len = plen; 854 } 855 return (ip); 856 857 dropfrag: 858 #ifdef IPDIVERT 859 frag_divert_port = 0; 860 ip_divert_cookie = 0; 861 #endif 862 ipstat.ips_fragdropped++; 863 m_freem(m); 864 return (0); 865 866 #undef GETIP 867 } 868 869 /* 870 * Free a fragment reassembly header and all 871 * associated datagrams. 872 */ 873 static void 874 ip_freef(fp) 875 struct ipq *fp; 876 { 877 register struct mbuf *q; 878 879 while (fp->ipq_frags) { 880 q = fp->ipq_frags; 881 fp->ipq_frags = q->m_nextpkt; 882 m_freem(q); 883 } 884 remque(fp); 885 (void) m_free(dtom(fp)); 886 nipq--; 887 } 888 889 /* 890 * IP timer processing; 891 * if a timer expires on a reassembly 892 * queue, discard it. 893 */ 894 void 895 ip_slowtimo() 896 { 897 register struct ipq *fp; 898 int s = splnet(); 899 int i; 900 901 for (i = 0; i < IPREASS_NHASH; i++) { 902 fp = ipq[i].next; 903 if (fp == 0) 904 continue; 905 while (fp != &ipq[i]) { 906 --fp->ipq_ttl; 907 fp = fp->next; 908 if (fp->prev->ipq_ttl == 0) { 909 ipstat.ips_fragtimeout++; 910 ip_freef(fp->prev); 911 } 912 } 913 } 914 ipflow_slowtimo(); 915 splx(s); 916 } 917 918 /* 919 * Drain off all datagram fragments. 920 */ 921 void 922 ip_drain() 923 { 924 int i; 925 926 for (i = 0; i < IPREASS_NHASH; i++) { 927 while (ipq[i].next != &ipq[i]) { 928 ipstat.ips_fragdropped++; 929 ip_freef(ipq[i].next); 930 } 931 } 932 in_rtqdrain(); 933 } 934 935 /* 936 * Do option processing on a datagram, 937 * possibly discarding it if bad options are encountered, 938 * or forwarding it if source-routed. 939 * Returns 1 if packet has been forwarded/freed, 940 * 0 if the packet should be processed further. 941 */ 942 static int 943 ip_dooptions(m) 944 struct mbuf *m; 945 { 946 register struct ip *ip = mtod(m, struct ip *); 947 register u_char *cp; 948 register struct ip_timestamp *ipt; 949 register struct in_ifaddr *ia; 950 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 951 struct in_addr *sin, dst; 952 n_time ntime; 953 954 dst = ip->ip_dst; 955 cp = (u_char *)(ip + 1); 956 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 957 for (; cnt > 0; cnt -= optlen, cp += optlen) { 958 opt = cp[IPOPT_OPTVAL]; 959 if (opt == IPOPT_EOL) 960 break; 961 if (opt == IPOPT_NOP) 962 optlen = 1; 963 else { 964 optlen = cp[IPOPT_OLEN]; 965 if (optlen <= 0 || optlen > cnt) { 966 code = &cp[IPOPT_OLEN] - (u_char *)ip; 967 goto bad; 968 } 969 } 970 switch (opt) { 971 972 default: 973 break; 974 975 /* 976 * Source routing with record. 977 * Find interface with current destination address. 978 * If none on this machine then drop if strictly routed, 979 * or do nothing if loosely routed. 980 * Record interface address and bring up next address 981 * component. If strictly routed make sure next 982 * address is on directly accessible net. 983 */ 984 case IPOPT_LSRR: 985 case IPOPT_SSRR: 986 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 987 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 988 goto bad; 989 } 990 ipaddr.sin_addr = ip->ip_dst; 991 ia = (struct in_ifaddr *) 992 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 993 if (ia == 0) { 994 if (opt == IPOPT_SSRR) { 995 type = ICMP_UNREACH; 996 code = ICMP_UNREACH_SRCFAIL; 997 goto bad; 998 } 999 if (!ip_dosourceroute) 1000 goto nosourcerouting; 1001 /* 1002 * Loose routing, and not at next destination 1003 * yet; nothing to do except forward. 1004 */ 1005 break; 1006 } 1007 off--; /* 0 origin */ 1008 if (off > optlen - sizeof(struct in_addr)) { 1009 /* 1010 * End of source route. Should be for us. 1011 */ 1012 if (!ip_acceptsourceroute) 1013 goto nosourcerouting; 1014 save_rte(cp, ip->ip_src); 1015 break; 1016 } 1017 1018 if (!ip_dosourceroute) { 1019 if (ipforwarding) { 1020 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1021 /* 1022 * Acting as a router, so generate ICMP 1023 */ 1024 nosourcerouting: 1025 strcpy(buf, inet_ntoa(ip->ip_dst)); 1026 log(LOG_WARNING, 1027 "attempted source route from %s to %s\n", 1028 inet_ntoa(ip->ip_src), buf); 1029 type = ICMP_UNREACH; 1030 code = ICMP_UNREACH_SRCFAIL; 1031 goto bad; 1032 } else { 1033 /* 1034 * Not acting as a router, so silently drop. 1035 */ 1036 ipstat.ips_cantforward++; 1037 m_freem(m); 1038 return (1); 1039 } 1040 } 1041 1042 /* 1043 * locate outgoing interface 1044 */ 1045 (void)memcpy(&ipaddr.sin_addr, cp + off, 1046 sizeof(ipaddr.sin_addr)); 1047 1048 if (opt == IPOPT_SSRR) { 1049 #define INA struct in_ifaddr * 1050 #define SA struct sockaddr * 1051 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1052 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1053 } else 1054 ia = ip_rtaddr(ipaddr.sin_addr); 1055 if (ia == 0) { 1056 type = ICMP_UNREACH; 1057 code = ICMP_UNREACH_SRCFAIL; 1058 goto bad; 1059 } 1060 ip->ip_dst = ipaddr.sin_addr; 1061 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1062 sizeof(struct in_addr)); 1063 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1064 /* 1065 * Let ip_intr's mcast routing check handle mcast pkts 1066 */ 1067 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1068 break; 1069 1070 case IPOPT_RR: 1071 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1072 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1073 goto bad; 1074 } 1075 /* 1076 * If no space remains, ignore. 1077 */ 1078 off--; /* 0 origin */ 1079 if (off > optlen - sizeof(struct in_addr)) 1080 break; 1081 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1082 sizeof(ipaddr.sin_addr)); 1083 /* 1084 * locate outgoing interface; if we're the destination, 1085 * use the incoming interface (should be same). 1086 */ 1087 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1088 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1089 type = ICMP_UNREACH; 1090 code = ICMP_UNREACH_HOST; 1091 goto bad; 1092 } 1093 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1094 sizeof(struct in_addr)); 1095 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1096 break; 1097 1098 case IPOPT_TS: 1099 code = cp - (u_char *)ip; 1100 ipt = (struct ip_timestamp *)cp; 1101 if (ipt->ipt_len < 5) 1102 goto bad; 1103 if (ipt->ipt_ptr > ipt->ipt_len - sizeof(int32_t)) { 1104 if (++ipt->ipt_oflw == 0) 1105 goto bad; 1106 break; 1107 } 1108 sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); 1109 switch (ipt->ipt_flg) { 1110 1111 case IPOPT_TS_TSONLY: 1112 break; 1113 1114 case IPOPT_TS_TSANDADDR: 1115 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1116 sizeof(struct in_addr) > ipt->ipt_len) 1117 goto bad; 1118 ipaddr.sin_addr = dst; 1119 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1120 m->m_pkthdr.rcvif); 1121 if (ia == 0) 1122 continue; 1123 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1124 sizeof(struct in_addr)); 1125 ipt->ipt_ptr += sizeof(struct in_addr); 1126 break; 1127 1128 case IPOPT_TS_PRESPEC: 1129 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1130 sizeof(struct in_addr) > ipt->ipt_len) 1131 goto bad; 1132 (void)memcpy(&ipaddr.sin_addr, sin, 1133 sizeof(struct in_addr)); 1134 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1135 continue; 1136 ipt->ipt_ptr += sizeof(struct in_addr); 1137 break; 1138 1139 default: 1140 goto bad; 1141 } 1142 ntime = iptime(); 1143 (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime, 1144 sizeof(n_time)); 1145 ipt->ipt_ptr += sizeof(n_time); 1146 } 1147 } 1148 if (forward && ipforwarding) { 1149 ip_forward(m, 1); 1150 return (1); 1151 } 1152 return (0); 1153 bad: 1154 ip->ip_len -= IP_VHL_HL(ip->ip_vhl) << 2; /* XXX icmp_error adds in hdr length */ 1155 icmp_error(m, type, code, 0, 0); 1156 ipstat.ips_badoptions++; 1157 return (1); 1158 } 1159 1160 /* 1161 * Given address of next destination (final or next hop), 1162 * return internet address info of interface to be used to get there. 1163 */ 1164 static struct in_ifaddr * 1165 ip_rtaddr(dst) 1166 struct in_addr dst; 1167 { 1168 register struct sockaddr_in *sin; 1169 1170 sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; 1171 1172 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 1173 if (ipforward_rt.ro_rt) { 1174 RTFREE(ipforward_rt.ro_rt); 1175 ipforward_rt.ro_rt = 0; 1176 } 1177 sin->sin_family = AF_INET; 1178 sin->sin_len = sizeof(*sin); 1179 sin->sin_addr = dst; 1180 1181 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1182 } 1183 if (ipforward_rt.ro_rt == 0) 1184 return ((struct in_ifaddr *)0); 1185 return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); 1186 } 1187 1188 /* 1189 * Save incoming source route for use in replies, 1190 * to be picked up later by ip_srcroute if the receiver is interested. 1191 */ 1192 void 1193 save_rte(option, dst) 1194 u_char *option; 1195 struct in_addr dst; 1196 { 1197 unsigned olen; 1198 1199 olen = option[IPOPT_OLEN]; 1200 #ifdef DIAGNOSTIC 1201 if (ipprintfs) 1202 printf("save_rte: olen %d\n", olen); 1203 #endif 1204 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1205 return; 1206 bcopy(option, ip_srcrt.srcopt, olen); 1207 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1208 ip_srcrt.dst = dst; 1209 } 1210 1211 /* 1212 * Retrieve incoming source route for use in replies, 1213 * in the same form used by setsockopt. 1214 * The first hop is placed before the options, will be removed later. 1215 */ 1216 struct mbuf * 1217 ip_srcroute() 1218 { 1219 register struct in_addr *p, *q; 1220 register struct mbuf *m; 1221 1222 if (ip_nhops == 0) 1223 return ((struct mbuf *)0); 1224 m = m_get(M_DONTWAIT, MT_HEADER); 1225 if (m == 0) 1226 return ((struct mbuf *)0); 1227 1228 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1229 1230 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1231 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1232 OPTSIZ; 1233 #ifdef DIAGNOSTIC 1234 if (ipprintfs) 1235 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1236 #endif 1237 1238 /* 1239 * First save first hop for return route 1240 */ 1241 p = &ip_srcrt.route[ip_nhops - 1]; 1242 *(mtod(m, struct in_addr *)) = *p--; 1243 #ifdef DIAGNOSTIC 1244 if (ipprintfs) 1245 printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr)); 1246 #endif 1247 1248 /* 1249 * Copy option fields and padding (nop) to mbuf. 1250 */ 1251 ip_srcrt.nop = IPOPT_NOP; 1252 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1253 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1254 &ip_srcrt.nop, OPTSIZ); 1255 q = (struct in_addr *)(mtod(m, caddr_t) + 1256 sizeof(struct in_addr) + OPTSIZ); 1257 #undef OPTSIZ 1258 /* 1259 * Record return path as an IP source route, 1260 * reversing the path (pointers are now aligned). 1261 */ 1262 while (p >= ip_srcrt.route) { 1263 #ifdef DIAGNOSTIC 1264 if (ipprintfs) 1265 printf(" %lx", ntohl(q->s_addr)); 1266 #endif 1267 *q++ = *p--; 1268 } 1269 /* 1270 * Last hop goes to final destination. 1271 */ 1272 *q = ip_srcrt.dst; 1273 #ifdef DIAGNOSTIC 1274 if (ipprintfs) 1275 printf(" %lx\n", ntohl(q->s_addr)); 1276 #endif 1277 return (m); 1278 } 1279 1280 /* 1281 * Strip out IP options, at higher 1282 * level protocol in the kernel. 1283 * Second argument is buffer to which options 1284 * will be moved, and return value is their length. 1285 * XXX should be deleted; last arg currently ignored. 1286 */ 1287 void 1288 ip_stripoptions(m, mopt) 1289 register struct mbuf *m; 1290 struct mbuf *mopt; 1291 { 1292 register int i; 1293 struct ip *ip = mtod(m, struct ip *); 1294 register caddr_t opts; 1295 int olen; 1296 1297 olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1298 opts = (caddr_t)(ip + 1); 1299 i = m->m_len - (sizeof (struct ip) + olen); 1300 bcopy(opts + olen, opts, (unsigned)i); 1301 m->m_len -= olen; 1302 if (m->m_flags & M_PKTHDR) 1303 m->m_pkthdr.len -= olen; 1304 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1305 } 1306 1307 u_char inetctlerrmap[PRC_NCMDS] = { 1308 0, 0, 0, 0, 1309 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1310 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1311 EMSGSIZE, EHOSTUNREACH, 0, 0, 1312 0, 0, 0, 0, 1313 ENOPROTOOPT 1314 }; 1315 1316 /* 1317 * Forward a packet. If some error occurs return the sender 1318 * an icmp packet. Note we can't always generate a meaningful 1319 * icmp message because icmp doesn't have a large enough repertoire 1320 * of codes and types. 1321 * 1322 * If not forwarding, just drop the packet. This could be confusing 1323 * if ipforwarding was zero but some routing protocol was advancing 1324 * us as a gateway to somewhere. However, we must let the routing 1325 * protocol deal with that. 1326 * 1327 * The srcrt parameter indicates whether the packet is being forwarded 1328 * via a source route. 1329 */ 1330 static void 1331 ip_forward(m, srcrt) 1332 struct mbuf *m; 1333 int srcrt; 1334 { 1335 register struct ip *ip = mtod(m, struct ip *); 1336 register struct sockaddr_in *sin; 1337 register struct rtentry *rt; 1338 int error, type = 0, code = 0; 1339 struct mbuf *mcopy; 1340 n_long dest; 1341 struct ifnet *destifp; 1342 1343 dest = 0; 1344 #ifdef DIAGNOSTIC 1345 if (ipprintfs) 1346 printf("forward: src %lx dst %lx ttl %x\n", 1347 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1348 ip->ip_ttl); 1349 #endif 1350 1351 1352 if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) { 1353 ipstat.ips_cantforward++; 1354 m_freem(m); 1355 return; 1356 } 1357 HTONS(ip->ip_id); 1358 if (ip->ip_ttl <= IPTTLDEC) { 1359 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1360 return; 1361 } 1362 ip->ip_ttl -= IPTTLDEC; 1363 1364 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1365 if ((rt = ipforward_rt.ro_rt) == 0 || 1366 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1367 if (ipforward_rt.ro_rt) { 1368 RTFREE(ipforward_rt.ro_rt); 1369 ipforward_rt.ro_rt = 0; 1370 } 1371 sin->sin_family = AF_INET; 1372 sin->sin_len = sizeof(*sin); 1373 sin->sin_addr = ip->ip_dst; 1374 1375 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1376 if (ipforward_rt.ro_rt == 0) { 1377 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1378 return; 1379 } 1380 rt = ipforward_rt.ro_rt; 1381 } 1382 1383 /* 1384 * Save at most 64 bytes of the packet in case 1385 * we need to generate an ICMP message to the src. 1386 */ 1387 mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); 1388 1389 /* 1390 * If forwarding packet using same interface that it came in on, 1391 * perhaps should send a redirect to sender to shortcut a hop. 1392 * Only send redirect if source is sending directly to us, 1393 * and if packet was not source routed (or has any options). 1394 * Also, don't send redirect if forwarding using a default route 1395 * or a route modified by a redirect. 1396 */ 1397 #define satosin(sa) ((struct sockaddr_in *)(sa)) 1398 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1399 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1400 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1401 ipsendredirects && !srcrt) { 1402 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1403 u_long src = ntohl(ip->ip_src.s_addr); 1404 1405 if (RTA(rt) && 1406 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1407 if (rt->rt_flags & RTF_GATEWAY) 1408 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1409 else 1410 dest = ip->ip_dst.s_addr; 1411 /* Router requirements says to only send host redirects */ 1412 type = ICMP_REDIRECT; 1413 code = ICMP_REDIRECT_HOST; 1414 #ifdef DIAGNOSTIC 1415 if (ipprintfs) 1416 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1417 #endif 1418 } 1419 } 1420 1421 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1422 IP_FORWARDING, 0); 1423 if (error) 1424 ipstat.ips_cantforward++; 1425 else { 1426 ipstat.ips_forward++; 1427 if (type) 1428 ipstat.ips_redirectsent++; 1429 else { 1430 if (mcopy) { 1431 ipflow_create(&ipforward_rt, mcopy); 1432 m_freem(mcopy); 1433 } 1434 return; 1435 } 1436 } 1437 if (mcopy == NULL) 1438 return; 1439 destifp = NULL; 1440 1441 switch (error) { 1442 1443 case 0: /* forwarded, but need redirect */ 1444 /* type, code set above */ 1445 break; 1446 1447 case ENETUNREACH: /* shouldn't happen, checked above */ 1448 case EHOSTUNREACH: 1449 case ENETDOWN: 1450 case EHOSTDOWN: 1451 default: 1452 type = ICMP_UNREACH; 1453 code = ICMP_UNREACH_HOST; 1454 break; 1455 1456 case EMSGSIZE: 1457 type = ICMP_UNREACH; 1458 code = ICMP_UNREACH_NEEDFRAG; 1459 if (ipforward_rt.ro_rt) 1460 destifp = ipforward_rt.ro_rt->rt_ifp; 1461 ipstat.ips_cantfrag++; 1462 break; 1463 1464 case ENOBUFS: 1465 type = ICMP_SOURCEQUENCH; 1466 code = 0; 1467 break; 1468 } 1469 icmp_error(mcopy, type, code, dest, destifp); 1470 } 1471 1472 void 1473 ip_savecontrol(inp, mp, ip, m) 1474 register struct inpcb *inp; 1475 register struct mbuf **mp; 1476 register struct ip *ip; 1477 register struct mbuf *m; 1478 { 1479 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1480 struct timeval tv; 1481 1482 microtime(&tv); 1483 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1484 SCM_TIMESTAMP, SOL_SOCKET); 1485 if (*mp) 1486 mp = &(*mp)->m_next; 1487 } 1488 if (inp->inp_flags & INP_RECVDSTADDR) { 1489 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1490 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1491 if (*mp) 1492 mp = &(*mp)->m_next; 1493 } 1494 #ifdef notyet 1495 /* XXX 1496 * Moving these out of udp_input() made them even more broken 1497 * than they already were. 1498 */ 1499 /* options were tossed already */ 1500 if (inp->inp_flags & INP_RECVOPTS) { 1501 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1502 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1503 if (*mp) 1504 mp = &(*mp)->m_next; 1505 } 1506 /* ip_srcroute doesn't do what we want here, need to fix */ 1507 if (inp->inp_flags & INP_RECVRETOPTS) { 1508 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1509 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1510 if (*mp) 1511 mp = &(*mp)->m_next; 1512 } 1513 #endif 1514 if (inp->inp_flags & INP_RECVIF) { 1515 struct ifnet *ifp; 1516 struct sdlbuf { 1517 struct sockaddr_dl sdl; 1518 u_char pad[32]; 1519 } sdlbuf; 1520 struct sockaddr_dl *sdp; 1521 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1522 1523 if (((ifp = m->m_pkthdr.rcvif)) 1524 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1525 sdp = (struct sockaddr_dl *)(ifnet_addrs 1526 [ifp->if_index - 1]->ifa_addr); 1527 /* 1528 * Change our mind and don't try copy. 1529 */ 1530 if ((sdp->sdl_family != AF_LINK) 1531 || (sdp->sdl_len > sizeof(sdlbuf))) { 1532 goto makedummy; 1533 } 1534 bcopy(sdp, sdl2, sdp->sdl_len); 1535 } else { 1536 makedummy: 1537 sdl2->sdl_len 1538 = offsetof(struct sockaddr_dl, sdl_data[0]); 1539 sdl2->sdl_family = AF_LINK; 1540 sdl2->sdl_index = 0; 1541 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1542 } 1543 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1544 IP_RECVIF, IPPROTO_IP); 1545 if (*mp) 1546 mp = &(*mp)->m_next; 1547 } 1548 } 1549 1550 int 1551 ip_rsvp_init(struct socket *so) 1552 { 1553 if (so->so_type != SOCK_RAW || 1554 so->so_proto->pr_protocol != IPPROTO_RSVP) 1555 return EOPNOTSUPP; 1556 1557 if (ip_rsvpd != NULL) 1558 return EADDRINUSE; 1559 1560 ip_rsvpd = so; 1561 /* 1562 * This may seem silly, but we need to be sure we don't over-increment 1563 * the RSVP counter, in case something slips up. 1564 */ 1565 if (!ip_rsvp_on) { 1566 ip_rsvp_on = 1; 1567 rsvp_on++; 1568 } 1569 1570 return 0; 1571 } 1572 1573 int 1574 ip_rsvp_done(void) 1575 { 1576 ip_rsvpd = NULL; 1577 /* 1578 * This may seem silly, but we need to be sure we don't over-decrement 1579 * the RSVP counter, in case something slips up. 1580 */ 1581 if (ip_rsvp_on) { 1582 ip_rsvp_on = 0; 1583 rsvp_on--; 1584 } 1585 return 0; 1586 } 1587