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 1.115 1999/02/22 18:19:57 des Exp $ 35 */ 36 37 #define _IP_VHL 38 39 #include "opt_bootp.h" 40 #include "opt_ipfw.h" 41 #include "opt_ipdn.h" 42 #include "opt_ipdivert.h" 43 #include "opt_ipfilter.h" 44 45 #include <stddef.h> 46 47 #include <sys/param.h> 48 #include <sys/systm.h> 49 #include <sys/mbuf.h> 50 #include <sys/malloc.h> 51 #include <sys/domain.h> 52 #include <sys/protosw.h> 53 #include <sys/socket.h> 54 #include <sys/time.h> 55 #include <sys/kernel.h> 56 #include <sys/syslog.h> 57 #include <sys/sysctl.h> 58 59 #include <net/if.h> 60 #include <net/if_var.h> 61 #include <net/if_dl.h> 62 #include <net/route.h> 63 #include <net/netisr.h> 64 65 #include <netinet/in.h> 66 #include <netinet/in_systm.h> 67 #include <netinet/in_var.h> 68 #include <netinet/ip.h> 69 #include <netinet/in_pcb.h> 70 #include <netinet/ip_var.h> 71 #include <netinet/ip_icmp.h> 72 #include <machine/in_cksum.h> 73 74 #include <sys/socketvar.h> 75 76 #ifdef IPFIREWALL 77 #include <netinet/ip_fw.h> 78 #endif 79 80 #ifdef DUMMYNET 81 #include <netinet/ip_dummynet.h> 82 #endif 83 84 int rsvp_on = 0; 85 static int ip_rsvp_on; 86 struct socket *ip_rsvpd; 87 88 int ipforwarding = 0; 89 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 90 &ipforwarding, 0, ""); 91 92 static int ipsendredirects = 1; /* XXX */ 93 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 94 &ipsendredirects, 0, ""); 95 96 int ip_defttl = IPDEFTTL; 97 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 98 &ip_defttl, 0, ""); 99 100 static int ip_dosourceroute = 0; 101 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 102 &ip_dosourceroute, 0, ""); 103 104 static int ip_acceptsourceroute = 0; 105 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 106 CTLFLAG_RW, &ip_acceptsourceroute, 0, ""); 107 #ifdef DIAGNOSTIC 108 static int ipprintfs = 0; 109 #endif 110 111 extern struct domain inetdomain; 112 extern struct protosw inetsw[]; 113 u_char ip_protox[IPPROTO_MAX]; 114 static int ipqmaxlen = IFQ_MAXLEN; 115 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 116 struct ifqueue ipintrq; 117 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RD, 118 &ipintrq.ifq_maxlen, 0, ""); 119 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 120 &ipintrq.ifq_drops, 0, ""); 121 122 struct ipstat ipstat; 123 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RD, 124 &ipstat, ipstat, ""); 125 126 /* Packet reassembly stuff */ 127 #define IPREASS_NHASH_LOG2 6 128 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 129 #define IPREASS_HMASK (IPREASS_NHASH - 1) 130 #define IPREASS_HASH(x,y) \ 131 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 132 133 static struct ipq ipq[IPREASS_NHASH]; 134 static int nipq = 0; /* total # of reass queues */ 135 static int maxnipq; 136 137 #ifdef IPCTL_DEFMTU 138 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 139 &ip_mtu, 0, ""); 140 #endif 141 142 #ifdef IPSTEALTH 143 static int ipstealth = 0; 144 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 145 &ipstealth, 0, ""); 146 #endif 147 148 #if !defined(COMPAT_IPFW) || COMPAT_IPFW == 1 149 #undef COMPAT_IPFW 150 #define COMPAT_IPFW 1 151 #else 152 #undef COMPAT_IPFW 153 #endif 154 155 #ifdef COMPAT_IPFW 156 157 #include <netinet/ip_fw.h> 158 159 /* Firewall hooks */ 160 ip_fw_chk_t *ip_fw_chk_ptr; 161 ip_fw_ctl_t *ip_fw_ctl_ptr; 162 163 #ifdef DUMMYNET 164 ip_dn_ctl_t *ip_dn_ctl_ptr; 165 #endif 166 167 /* IP Network Address Translation (NAT) hooks */ 168 ip_nat_t *ip_nat_ptr; 169 ip_nat_ctl_t *ip_nat_ctl_ptr; 170 #endif 171 172 #if defined(IPFILTER_LKM) || defined(IPFILTER) 173 int iplattach __P((void)); 174 int (*fr_checkp) __P((struct ip *, int, struct ifnet *, int, struct mbuf **)) = NULL; 175 #endif 176 177 178 /* 179 * We need to save the IP options in case a protocol wants to respond 180 * to an incoming packet over the same route if the packet got here 181 * using IP source routing. This allows connection establishment and 182 * maintenance when the remote end is on a network that is not known 183 * to us. 184 */ 185 static int ip_nhops = 0; 186 static struct ip_srcrt { 187 struct in_addr dst; /* final destination */ 188 char nop; /* one NOP to align */ 189 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 190 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 191 } ip_srcrt; 192 193 #ifdef IPDIVERT 194 /* 195 * Shared variable between ip_input() and ip_reass() to communicate 196 * about which packets, once assembled from fragments, get diverted, 197 * and to which port. 198 */ 199 static u_short frag_divert_port; 200 #endif 201 202 struct sockaddr_in *ip_fw_fwd_addr; 203 204 static void save_rte __P((u_char *, struct in_addr)); 205 static int ip_dooptions __P((struct mbuf *)); 206 static void ip_forward __P((struct mbuf *, int)); 207 static void ip_freef __P((struct ipq *)); 208 static struct ip * 209 ip_reass __P((struct mbuf *, struct ipq *, struct ipq *)); 210 static struct in_ifaddr * 211 ip_rtaddr __P((struct in_addr)); 212 static void ipintr __P((void)); 213 /* 214 * IP initialization: fill in IP protocol switch table. 215 * All protocols not implemented in kernel go to raw IP protocol handler. 216 */ 217 void 218 ip_init() 219 { 220 register struct protosw *pr; 221 register int i; 222 223 TAILQ_INIT(&in_ifaddrhead); 224 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 225 if (pr == 0) 226 panic("ip_init"); 227 for (i = 0; i < IPPROTO_MAX; i++) 228 ip_protox[i] = pr - inetsw; 229 for (pr = inetdomain.dom_protosw; 230 pr < inetdomain.dom_protoswNPROTOSW; pr++) 231 if (pr->pr_domain->dom_family == PF_INET && 232 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 233 ip_protox[pr->pr_protocol] = pr - inetsw; 234 235 for (i = 0; i < IPREASS_NHASH; i++) 236 ipq[i].next = ipq[i].prev = &ipq[i]; 237 238 maxnipq = nmbclusters/4; 239 240 ip_id = time_second & 0xffff; 241 ipintrq.ifq_maxlen = ipqmaxlen; 242 #ifdef DUMMYNET 243 ip_dn_init(); 244 #endif 245 #ifdef IPNAT 246 ip_nat_init(); 247 #endif 248 #ifdef IPFILTER 249 iplattach(); 250 #endif 251 252 } 253 254 static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 255 static struct route ipforward_rt; 256 257 /* 258 * Ip input routine. Checksum and byte swap header. If fragmented 259 * try to reassemble. Process options. Pass to next level. 260 */ 261 void 262 ip_input(struct mbuf *m) 263 { 264 struct ip *ip; 265 struct ipq *fp; 266 struct in_ifaddr *ia; 267 int i, hlen, mff; 268 u_short sum; 269 #ifndef IPDIVERT /* dummy variable for the firewall code to play with */ 270 u_short ip_divert_cookie = 0 ; 271 #endif 272 #ifdef COMPAT_IPFW 273 struct ip_fw_chain *rule = NULL ; 274 #endif 275 276 #if defined(IPFIREWALL) && defined(DUMMYNET) 277 /* 278 * dummynet packet are prepended a vestigial mbuf with 279 * m_type = MT_DUMMYNET and m_data pointing to the matching 280 * rule. 281 */ 282 if (m->m_type == MT_DUMMYNET) { 283 struct mbuf *m0 = m ; 284 rule = (struct ip_fw_chain *)(m->m_data) ; 285 m = m->m_next ; 286 free(m0, M_IPFW); 287 ip = mtod(m, struct ip *); 288 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 289 goto iphack ; 290 } else 291 rule = NULL ; 292 #endif 293 294 #ifdef DIAGNOSTIC 295 if (m == NULL || (m->m_flags & M_PKTHDR) == 0) 296 panic("ip_input no HDR"); 297 #endif 298 ipstat.ips_total++; 299 300 if (m->m_pkthdr.len < sizeof(struct ip)) 301 goto tooshort; 302 303 if (m->m_len < sizeof (struct ip) && 304 (m = m_pullup(m, sizeof (struct ip))) == 0) { 305 ipstat.ips_toosmall++; 306 return; 307 } 308 ip = mtod(m, struct ip *); 309 310 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 311 ipstat.ips_badvers++; 312 goto bad; 313 } 314 315 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 316 if (hlen < sizeof(struct ip)) { /* minimum header length */ 317 ipstat.ips_badhlen++; 318 goto bad; 319 } 320 if (hlen > m->m_len) { 321 if ((m = m_pullup(m, hlen)) == 0) { 322 ipstat.ips_badhlen++; 323 return; 324 } 325 ip = mtod(m, struct ip *); 326 } 327 if (hlen == sizeof(struct ip)) { 328 sum = in_cksum_hdr(ip); 329 } else { 330 sum = in_cksum(m, hlen); 331 } 332 if (sum) { 333 ipstat.ips_badsum++; 334 goto bad; 335 } 336 337 /* 338 * Convert fields to host representation. 339 */ 340 NTOHS(ip->ip_len); 341 if (ip->ip_len < hlen) { 342 ipstat.ips_badlen++; 343 goto bad; 344 } 345 NTOHS(ip->ip_id); 346 NTOHS(ip->ip_off); 347 348 /* 349 * Check that the amount of data in the buffers 350 * is as at least much as the IP header would have us expect. 351 * Trim mbufs if longer than we expect. 352 * Drop packet if shorter than we expect. 353 */ 354 if (m->m_pkthdr.len < ip->ip_len) { 355 tooshort: 356 ipstat.ips_tooshort++; 357 goto bad; 358 } 359 if (m->m_pkthdr.len > ip->ip_len) { 360 if (m->m_len == m->m_pkthdr.len) { 361 m->m_len = ip->ip_len; 362 m->m_pkthdr.len = ip->ip_len; 363 } else 364 m_adj(m, ip->ip_len - m->m_pkthdr.len); 365 } 366 /* 367 * IpHack's section. 368 * Right now when no processing on packet has done 369 * and it is still fresh out of network we do our black 370 * deals with it. 371 * - Firewall: deny/allow/divert 372 * - Xlate: translate packet's addr/port (NAT). 373 * - Pipe: pass pkt through dummynet. 374 * - Wrap: fake packet's addr/port <unimpl.> 375 * - Encapsulate: put it in another IP and send out. <unimp.> 376 */ 377 378 #if defined(IPFIREWALL) && defined(DUMMYNET) 379 iphack: 380 #endif 381 #if defined(IPFILTER) || defined(IPFILTER_LKM) 382 /* 383 * Check if we want to allow this packet to be processed. 384 * Consider it to be bad if not. 385 */ 386 if (fr_checkp) { 387 struct mbuf *m1 = m; 388 389 if ((*fr_checkp)(ip, hlen, m->m_pkthdr.rcvif, 0, &m1) || !m1) 390 return; 391 ip = mtod(m = m1, struct ip *); 392 } 393 #endif 394 #ifdef COMPAT_IPFW 395 if (ip_fw_chk_ptr) { 396 #ifdef IPFIREWALL_FORWARD 397 /* 398 * If we've been forwarded from the output side, then 399 * skip the firewall a second time 400 */ 401 if (ip_fw_fwd_addr) 402 goto ours; 403 #endif /* IPFIREWALL_FORWARD */ 404 i = (*ip_fw_chk_ptr)(&ip, hlen, NULL, &ip_divert_cookie, 405 &m, &rule, &ip_fw_fwd_addr); 406 /* 407 * see the comment in ip_output for the return values 408 * produced by the firewall. 409 */ 410 if (!m) /* packet discarded by firewall */ 411 return ; 412 if (i == 0 && ip_fw_fwd_addr == NULL) /* common case */ 413 goto pass ; 414 #ifdef DUMMYNET 415 if (i & 0x10000) { 416 /* send packet to the appropriate pipe */ 417 dummynet_io(i&0xffff,DN_TO_IP_IN,m,NULL,NULL,0, rule); 418 return ; 419 } 420 #endif 421 #ifdef IPDIVERT 422 if (i > 0 && i < 0x10000) { 423 /* Divert packet */ 424 frag_divert_port = i & 0xffff ; 425 goto ours; 426 } 427 #endif 428 #ifdef IPFIREWALL_FORWARD 429 if (i == 0 && ip_fw_fwd_addr != NULL) 430 goto pass ; 431 #endif 432 /* 433 * if we get here, the packet must be dropped 434 */ 435 m_freem(m); 436 return; 437 } 438 pass: 439 440 if (ip_nat_ptr && !(*ip_nat_ptr)(&ip, &m, m->m_pkthdr.rcvif, IP_NAT_IN)) { 441 #ifdef IPFIREWALL_FORWARD 442 ip_fw_fwd_addr = NULL; 443 #endif 444 return; 445 } 446 #endif /* !COMPAT_IPFW */ 447 448 /* 449 * Process options and, if not destined for us, 450 * ship it on. ip_dooptions returns 1 when an 451 * error was detected (causing an icmp message 452 * to be sent and the original packet to be freed). 453 */ 454 ip_nhops = 0; /* for source routed packets */ 455 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 456 #ifdef IPFIREWALL_FORWARD 457 ip_fw_fwd_addr = NULL; 458 #endif 459 return; 460 } 461 462 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 463 * matter if it is destined to another node, or whether it is 464 * a multicast one, RSVP wants it! and prevents it from being forwarded 465 * anywhere else. Also checks if the rsvp daemon is running before 466 * grabbing the packet. 467 */ 468 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 469 goto ours; 470 471 /* 472 * Check our list of addresses, to see if the packet is for us. 473 * If we don't have any addresses, assume any unicast packet 474 * we receive might be for us (and let the upper layers deal 475 * with it). 476 */ 477 if (TAILQ_EMPTY(&in_ifaddrhead) && 478 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 479 goto ours; 480 481 for (ia = TAILQ_FIRST(&in_ifaddrhead); ia; 482 ia = TAILQ_NEXT(ia, ia_link)) { 483 #define satosin(sa) ((struct sockaddr_in *)(sa)) 484 485 #ifdef BOOTP_COMPAT 486 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 487 goto ours; 488 #endif 489 #ifdef IPFIREWALL_FORWARD 490 /* 491 * If the addr to forward to is one of ours, we pretend to 492 * be the destination for this packet. 493 */ 494 if (ip_fw_fwd_addr == NULL) { 495 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 496 goto ours; 497 } else if (IA_SIN(ia)->sin_addr.s_addr == 498 ip_fw_fwd_addr->sin_addr.s_addr) 499 goto ours; 500 #else 501 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 502 goto ours; 503 #endif 504 if (ia->ia_ifp && ia->ia_ifp->if_flags & IFF_BROADCAST) { 505 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 506 ip->ip_dst.s_addr) 507 goto ours; 508 if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr) 509 goto ours; 510 } 511 } 512 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 513 struct in_multi *inm; 514 if (ip_mrouter) { 515 /* 516 * If we are acting as a multicast router, all 517 * incoming multicast packets are passed to the 518 * kernel-level multicast forwarding function. 519 * The packet is returned (relatively) intact; if 520 * ip_mforward() returns a non-zero value, the packet 521 * must be discarded, else it may be accepted below. 522 * 523 * (The IP ident field is put in the same byte order 524 * as expected when ip_mforward() is called from 525 * ip_output().) 526 */ 527 ip->ip_id = htons(ip->ip_id); 528 if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 529 ipstat.ips_cantforward++; 530 m_freem(m); 531 return; 532 } 533 ip->ip_id = ntohs(ip->ip_id); 534 535 /* 536 * The process-level routing demon needs to receive 537 * all multicast IGMP packets, whether or not this 538 * host belongs to their destination groups. 539 */ 540 if (ip->ip_p == IPPROTO_IGMP) 541 goto ours; 542 ipstat.ips_forward++; 543 } 544 /* 545 * See if we belong to the destination multicast group on the 546 * arrival interface. 547 */ 548 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 549 if (inm == NULL) { 550 ipstat.ips_notmember++; 551 m_freem(m); 552 return; 553 } 554 goto ours; 555 } 556 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 557 goto ours; 558 if (ip->ip_dst.s_addr == INADDR_ANY) 559 goto ours; 560 561 /* 562 * Not for us; forward if possible and desirable. 563 */ 564 if (ipforwarding == 0) { 565 ipstat.ips_cantforward++; 566 m_freem(m); 567 } else 568 ip_forward(m, 0); 569 #ifdef IPFIREWALL_FORWARD 570 ip_fw_fwd_addr = NULL; 571 #endif 572 return; 573 574 ours: 575 576 /* 577 * If offset or IP_MF are set, must reassemble. 578 * Otherwise, nothing need be done. 579 * (We could look in the reassembly queue to see 580 * if the packet was previously fragmented, 581 * but it's not worth the time; just let them time out.) 582 */ 583 if (ip->ip_off & (IP_MF | IP_OFFMASK | IP_RF)) { 584 if (m->m_flags & M_EXT) { /* XXX */ 585 if ((m = m_pullup(m, hlen)) == 0) { 586 ipstat.ips_toosmall++; 587 #ifdef IPDIVERT 588 frag_divert_port = 0; 589 ip_divert_cookie = 0; 590 #endif 591 #ifdef IPFIREWALL_FORWARD 592 ip_fw_fwd_addr = NULL; 593 #endif 594 return; 595 } 596 ip = mtod(m, struct ip *); 597 } 598 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 599 /* 600 * Look for queue of fragments 601 * of this datagram. 602 */ 603 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 604 if (ip->ip_id == fp->ipq_id && 605 ip->ip_src.s_addr == fp->ipq_src.s_addr && 606 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 607 ip->ip_p == fp->ipq_p) 608 goto found; 609 610 fp = 0; 611 612 /* check if there's a place for the new queue */ 613 if (nipq > maxnipq) { 614 /* 615 * drop something from the tail of the current queue 616 * before proceeding further 617 */ 618 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 619 for (i = 0; i < IPREASS_NHASH; i++) { 620 if (ipq[i].prev != &ipq[i]) { 621 ip_freef(ipq[i].prev); 622 break; 623 } 624 } 625 } else 626 ip_freef(ipq[sum].prev); 627 } 628 found: 629 /* 630 * Adjust ip_len to not reflect header, 631 * set ip_mff if more fragments are expected, 632 * convert offset of this to bytes. 633 */ 634 ip->ip_len -= hlen; 635 mff = (ip->ip_off & IP_MF) != 0; 636 if (mff) { 637 /* 638 * Make sure that fragments have a data length 639 * that's a non-zero multiple of 8 bytes. 640 */ 641 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 642 ipstat.ips_toosmall++; /* XXX */ 643 goto bad; 644 } 645 m->m_flags |= M_FRAG; 646 } 647 ip->ip_off <<= 3; 648 649 /* 650 * If datagram marked as having more fragments 651 * or if this is not the first fragment, 652 * attempt reassembly; if it succeeds, proceed. 653 */ 654 if (mff || ip->ip_off) { 655 ipstat.ips_fragments++; 656 m->m_pkthdr.header = ip; 657 ip = ip_reass(m, fp, &ipq[sum]); 658 if (ip == 0) { 659 #ifdef IPFIREWALL_FORWARD 660 ip_fw_fwd_addr = NULL; 661 #endif 662 return; 663 } 664 /* Get the length of the reassembled packets header */ 665 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 666 ipstat.ips_reassembled++; 667 m = dtom(ip); 668 #ifdef IPDIVERT 669 if (frag_divert_port) { 670 ip->ip_len += hlen; 671 HTONS(ip->ip_len); 672 HTONS(ip->ip_off); 673 HTONS(ip->ip_id); 674 ip->ip_sum = 0; 675 ip->ip_sum = in_cksum_hdr(ip); 676 NTOHS(ip->ip_id); 677 NTOHS(ip->ip_off); 678 NTOHS(ip->ip_len); 679 ip->ip_len -= hlen; 680 } 681 #endif 682 } else 683 if (fp) 684 ip_freef(fp); 685 } else 686 ip->ip_len -= hlen; 687 688 #ifdef IPDIVERT 689 /* 690 * Divert reassembled packets to the divert protocol if required 691 * If divert port is null then cookie should be too, 692 * so we shouldn't need to clear them here. Assume ip_divert does so. 693 */ 694 if (frag_divert_port) { 695 ipstat.ips_delivered++; 696 ip_divert_port = frag_divert_port; 697 frag_divert_port = 0; 698 (*inetsw[ip_protox[IPPROTO_DIVERT]].pr_input)(m, hlen); 699 return; 700 } 701 702 /* Don't let packets divert themselves */ 703 if (ip->ip_p == IPPROTO_DIVERT) { 704 ipstat.ips_noproto++; 705 goto bad; 706 } 707 708 #endif 709 710 /* 711 * Switch out to protocol's input routine. 712 */ 713 ipstat.ips_delivered++; 714 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 715 #ifdef IPFIREWALL_FORWARD 716 ip_fw_fwd_addr = NULL; /* tcp needed it */ 717 #endif 718 return; 719 bad: 720 #ifdef IPFIREWALL_FORWARD 721 ip_fw_fwd_addr = NULL; 722 #endif 723 m_freem(m); 724 } 725 726 /* 727 * IP software interrupt routine - to go away sometime soon 728 */ 729 static void 730 ipintr(void) 731 { 732 int s; 733 struct mbuf *m; 734 735 while(1) { 736 s = splimp(); 737 IF_DEQUEUE(&ipintrq, m); 738 splx(s); 739 if (m == 0) 740 return; 741 ip_input(m); 742 } 743 } 744 745 NETISR_SET(NETISR_IP, ipintr); 746 747 /* 748 * Take incoming datagram fragment and try to 749 * reassemble it into whole datagram. If a chain for 750 * reassembly of this datagram already exists, then it 751 * is given as fp; otherwise have to make a chain. 752 */ 753 static struct ip * 754 ip_reass(m, fp, where) 755 register struct mbuf *m; 756 register struct ipq *fp; 757 struct ipq *where; 758 { 759 struct ip *ip = mtod(m, struct ip *); 760 register struct mbuf *p = 0, *q, *nq; 761 struct mbuf *t; 762 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 763 int i, next; 764 765 /* 766 * Presence of header sizes in mbufs 767 * would confuse code below. 768 */ 769 m->m_data += hlen; 770 m->m_len -= hlen; 771 772 /* 773 * If first fragment to arrive, create a reassembly queue. 774 */ 775 if (fp == 0) { 776 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 777 goto dropfrag; 778 fp = mtod(t, struct ipq *); 779 insque(fp, where); 780 nipq++; 781 fp->ipq_ttl = IPFRAGTTL; 782 fp->ipq_p = ip->ip_p; 783 fp->ipq_id = ip->ip_id; 784 fp->ipq_src = ip->ip_src; 785 fp->ipq_dst = ip->ip_dst; 786 fp->ipq_frags = m; 787 m->m_nextpkt = NULL; 788 #ifdef IPDIVERT 789 fp->ipq_divert = 0; 790 fp->ipq_div_cookie = 0; 791 #endif 792 goto inserted; 793 } 794 795 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 796 797 /* 798 * Find a segment which begins after this one does. 799 */ 800 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 801 if (GETIP(q)->ip_off > ip->ip_off) 802 break; 803 804 /* 805 * If there is a preceding segment, it may provide some of 806 * our data already. If so, drop the data from the incoming 807 * segment. If it provides all of our data, drop us, otherwise 808 * stick new segment in the proper place. 809 */ 810 if (p) { 811 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 812 if (i > 0) { 813 if (i >= ip->ip_len) 814 goto dropfrag; 815 m_adj(dtom(ip), i); 816 ip->ip_off += i; 817 ip->ip_len -= i; 818 } 819 m->m_nextpkt = p->m_nextpkt; 820 p->m_nextpkt = m; 821 } else { 822 m->m_nextpkt = fp->ipq_frags; 823 fp->ipq_frags = m; 824 } 825 826 /* 827 * While we overlap succeeding segments trim them or, 828 * if they are completely covered, dequeue them. 829 */ 830 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 831 q = nq) { 832 i = (ip->ip_off + ip->ip_len) - 833 GETIP(q)->ip_off; 834 if (i < GETIP(q)->ip_len) { 835 GETIP(q)->ip_len -= i; 836 GETIP(q)->ip_off += i; 837 m_adj(q, i); 838 break; 839 } 840 nq = q->m_nextpkt; 841 m->m_nextpkt = nq; 842 m_freem(q); 843 } 844 845 inserted: 846 847 #ifdef IPDIVERT 848 /* 849 * Any fragment diverting causes the whole packet to divert 850 */ 851 if (frag_divert_port) { 852 fp->ipq_divert = frag_divert_port; 853 fp->ipq_div_cookie = ip_divert_cookie; 854 } 855 frag_divert_port = 0; 856 ip_divert_cookie = 0; 857 #endif 858 859 /* 860 * Check for complete reassembly. 861 */ 862 next = 0; 863 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 864 if (GETIP(q)->ip_off != next) 865 return (0); 866 next += GETIP(q)->ip_len; 867 } 868 /* Make sure the last packet didn't have the IP_MF flag */ 869 if (p->m_flags & M_FRAG) 870 return (0); 871 872 /* 873 * Reassembly is complete. Make sure the packet is a sane size. 874 */ 875 q = fp->ipq_frags; 876 ip = GETIP(q); 877 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 878 ipstat.ips_toolong++; 879 ip_freef(fp); 880 return (0); 881 } 882 883 /* 884 * Concatenate fragments. 885 */ 886 m = q; 887 t = m->m_next; 888 m->m_next = 0; 889 m_cat(m, t); 890 nq = q->m_nextpkt; 891 q->m_nextpkt = 0; 892 for (q = nq; q != NULL; q = nq) { 893 nq = q->m_nextpkt; 894 q->m_nextpkt = NULL; 895 m_cat(m, q); 896 } 897 898 #ifdef IPDIVERT 899 /* 900 * extract divert port for packet, if any 901 */ 902 frag_divert_port = fp->ipq_divert; 903 ip_divert_cookie = fp->ipq_div_cookie; 904 #endif 905 906 /* 907 * Create header for new ip packet by 908 * modifying header of first packet; 909 * dequeue and discard fragment reassembly header. 910 * Make header visible. 911 */ 912 ip->ip_len = next; 913 ip->ip_src = fp->ipq_src; 914 ip->ip_dst = fp->ipq_dst; 915 remque(fp); 916 nipq--; 917 (void) m_free(dtom(fp)); 918 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 919 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 920 /* some debugging cruft by sklower, below, will go away soon */ 921 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 922 register int plen = 0; 923 for (t = m; m; m = m->m_next) 924 plen += m->m_len; 925 t->m_pkthdr.len = plen; 926 } 927 return (ip); 928 929 dropfrag: 930 #ifdef IPDIVERT 931 frag_divert_port = 0; 932 ip_divert_cookie = 0; 933 #endif 934 ipstat.ips_fragdropped++; 935 m_freem(m); 936 return (0); 937 938 #undef GETIP 939 } 940 941 /* 942 * Free a fragment reassembly header and all 943 * associated datagrams. 944 */ 945 static void 946 ip_freef(fp) 947 struct ipq *fp; 948 { 949 register struct mbuf *q; 950 951 while (fp->ipq_frags) { 952 q = fp->ipq_frags; 953 fp->ipq_frags = q->m_nextpkt; 954 m_freem(q); 955 } 956 remque(fp); 957 (void) m_free(dtom(fp)); 958 nipq--; 959 } 960 961 /* 962 * IP timer processing; 963 * if a timer expires on a reassembly 964 * queue, discard it. 965 */ 966 void 967 ip_slowtimo() 968 { 969 register struct ipq *fp; 970 int s = splnet(); 971 int i; 972 973 for (i = 0; i < IPREASS_NHASH; i++) { 974 fp = ipq[i].next; 975 if (fp == 0) 976 continue; 977 while (fp != &ipq[i]) { 978 --fp->ipq_ttl; 979 fp = fp->next; 980 if (fp->prev->ipq_ttl == 0) { 981 ipstat.ips_fragtimeout++; 982 ip_freef(fp->prev); 983 } 984 } 985 } 986 ipflow_slowtimo(); 987 splx(s); 988 } 989 990 /* 991 * Drain off all datagram fragments. 992 */ 993 void 994 ip_drain() 995 { 996 int i; 997 998 for (i = 0; i < IPREASS_NHASH; i++) { 999 while (ipq[i].next != &ipq[i]) { 1000 ipstat.ips_fragdropped++; 1001 ip_freef(ipq[i].next); 1002 } 1003 } 1004 in_rtqdrain(); 1005 } 1006 1007 /* 1008 * Do option processing on a datagram, 1009 * possibly discarding it if bad options are encountered, 1010 * or forwarding it if source-routed. 1011 * Returns 1 if packet has been forwarded/freed, 1012 * 0 if the packet should be processed further. 1013 */ 1014 static int 1015 ip_dooptions(m) 1016 struct mbuf *m; 1017 { 1018 register struct ip *ip = mtod(m, struct ip *); 1019 register u_char *cp; 1020 register struct ip_timestamp *ipt; 1021 register struct in_ifaddr *ia; 1022 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1023 struct in_addr *sin, dst; 1024 n_time ntime; 1025 1026 dst = ip->ip_dst; 1027 cp = (u_char *)(ip + 1); 1028 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1029 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1030 opt = cp[IPOPT_OPTVAL]; 1031 if (opt == IPOPT_EOL) 1032 break; 1033 if (opt == IPOPT_NOP) 1034 optlen = 1; 1035 else { 1036 optlen = cp[IPOPT_OLEN]; 1037 if (optlen <= 0 || optlen > cnt) { 1038 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1039 goto bad; 1040 } 1041 } 1042 switch (opt) { 1043 1044 default: 1045 break; 1046 1047 /* 1048 * Source routing with record. 1049 * Find interface with current destination address. 1050 * If none on this machine then drop if strictly routed, 1051 * or do nothing if loosely routed. 1052 * Record interface address and bring up next address 1053 * component. If strictly routed make sure next 1054 * address is on directly accessible net. 1055 */ 1056 case IPOPT_LSRR: 1057 case IPOPT_SSRR: 1058 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1059 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1060 goto bad; 1061 } 1062 ipaddr.sin_addr = ip->ip_dst; 1063 ia = (struct in_ifaddr *) 1064 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1065 if (ia == 0) { 1066 if (opt == IPOPT_SSRR) { 1067 type = ICMP_UNREACH; 1068 code = ICMP_UNREACH_SRCFAIL; 1069 goto bad; 1070 } 1071 if (!ip_dosourceroute) 1072 goto nosourcerouting; 1073 /* 1074 * Loose routing, and not at next destination 1075 * yet; nothing to do except forward. 1076 */ 1077 break; 1078 } 1079 off--; /* 0 origin */ 1080 if (off > optlen - sizeof(struct in_addr)) { 1081 /* 1082 * End of source route. Should be for us. 1083 */ 1084 if (!ip_acceptsourceroute) 1085 goto nosourcerouting; 1086 save_rte(cp, ip->ip_src); 1087 break; 1088 } 1089 1090 if (!ip_dosourceroute) { 1091 if (ipforwarding) { 1092 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1093 /* 1094 * Acting as a router, so generate ICMP 1095 */ 1096 nosourcerouting: 1097 strcpy(buf, inet_ntoa(ip->ip_dst)); 1098 log(LOG_WARNING, 1099 "attempted source route from %s to %s\n", 1100 inet_ntoa(ip->ip_src), buf); 1101 type = ICMP_UNREACH; 1102 code = ICMP_UNREACH_SRCFAIL; 1103 goto bad; 1104 } else { 1105 /* 1106 * Not acting as a router, so silently drop. 1107 */ 1108 ipstat.ips_cantforward++; 1109 m_freem(m); 1110 return (1); 1111 } 1112 } 1113 1114 /* 1115 * locate outgoing interface 1116 */ 1117 (void)memcpy(&ipaddr.sin_addr, cp + off, 1118 sizeof(ipaddr.sin_addr)); 1119 1120 if (opt == IPOPT_SSRR) { 1121 #define INA struct in_ifaddr * 1122 #define SA struct sockaddr * 1123 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1124 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1125 } else 1126 ia = ip_rtaddr(ipaddr.sin_addr); 1127 if (ia == 0) { 1128 type = ICMP_UNREACH; 1129 code = ICMP_UNREACH_SRCFAIL; 1130 goto bad; 1131 } 1132 ip->ip_dst = ipaddr.sin_addr; 1133 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1134 sizeof(struct in_addr)); 1135 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1136 /* 1137 * Let ip_intr's mcast routing check handle mcast pkts 1138 */ 1139 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1140 break; 1141 1142 case IPOPT_RR: 1143 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1144 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1145 goto bad; 1146 } 1147 /* 1148 * If no space remains, ignore. 1149 */ 1150 off--; /* 0 origin */ 1151 if (off > optlen - sizeof(struct in_addr)) 1152 break; 1153 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1154 sizeof(ipaddr.sin_addr)); 1155 /* 1156 * locate outgoing interface; if we're the destination, 1157 * use the incoming interface (should be same). 1158 */ 1159 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1160 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1161 type = ICMP_UNREACH; 1162 code = ICMP_UNREACH_HOST; 1163 goto bad; 1164 } 1165 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1166 sizeof(struct in_addr)); 1167 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1168 break; 1169 1170 case IPOPT_TS: 1171 code = cp - (u_char *)ip; 1172 ipt = (struct ip_timestamp *)cp; 1173 if (ipt->ipt_len < 5) 1174 goto bad; 1175 if (ipt->ipt_ptr > ipt->ipt_len - sizeof(int32_t)) { 1176 if (++ipt->ipt_oflw == 0) 1177 goto bad; 1178 break; 1179 } 1180 sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); 1181 switch (ipt->ipt_flg) { 1182 1183 case IPOPT_TS_TSONLY: 1184 break; 1185 1186 case IPOPT_TS_TSANDADDR: 1187 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1188 sizeof(struct in_addr) > ipt->ipt_len) 1189 goto bad; 1190 ipaddr.sin_addr = dst; 1191 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1192 m->m_pkthdr.rcvif); 1193 if (ia == 0) 1194 continue; 1195 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1196 sizeof(struct in_addr)); 1197 ipt->ipt_ptr += sizeof(struct in_addr); 1198 break; 1199 1200 case IPOPT_TS_PRESPEC: 1201 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1202 sizeof(struct in_addr) > ipt->ipt_len) 1203 goto bad; 1204 (void)memcpy(&ipaddr.sin_addr, sin, 1205 sizeof(struct in_addr)); 1206 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1207 continue; 1208 ipt->ipt_ptr += sizeof(struct in_addr); 1209 break; 1210 1211 default: 1212 goto bad; 1213 } 1214 ntime = iptime(); 1215 (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime, 1216 sizeof(n_time)); 1217 ipt->ipt_ptr += sizeof(n_time); 1218 } 1219 } 1220 if (forward && ipforwarding) { 1221 ip_forward(m, 1); 1222 return (1); 1223 } 1224 return (0); 1225 bad: 1226 ip->ip_len -= IP_VHL_HL(ip->ip_vhl) << 2; /* XXX icmp_error adds in hdr length */ 1227 icmp_error(m, type, code, 0, 0); 1228 ipstat.ips_badoptions++; 1229 return (1); 1230 } 1231 1232 /* 1233 * Given address of next destination (final or next hop), 1234 * return internet address info of interface to be used to get there. 1235 */ 1236 static struct in_ifaddr * 1237 ip_rtaddr(dst) 1238 struct in_addr dst; 1239 { 1240 register struct sockaddr_in *sin; 1241 1242 sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; 1243 1244 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 1245 if (ipforward_rt.ro_rt) { 1246 RTFREE(ipforward_rt.ro_rt); 1247 ipforward_rt.ro_rt = 0; 1248 } 1249 sin->sin_family = AF_INET; 1250 sin->sin_len = sizeof(*sin); 1251 sin->sin_addr = dst; 1252 1253 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1254 } 1255 if (ipforward_rt.ro_rt == 0) 1256 return ((struct in_ifaddr *)0); 1257 return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); 1258 } 1259 1260 /* 1261 * Save incoming source route for use in replies, 1262 * to be picked up later by ip_srcroute if the receiver is interested. 1263 */ 1264 void 1265 save_rte(option, dst) 1266 u_char *option; 1267 struct in_addr dst; 1268 { 1269 unsigned olen; 1270 1271 olen = option[IPOPT_OLEN]; 1272 #ifdef DIAGNOSTIC 1273 if (ipprintfs) 1274 printf("save_rte: olen %d\n", olen); 1275 #endif 1276 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1277 return; 1278 bcopy(option, ip_srcrt.srcopt, olen); 1279 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1280 ip_srcrt.dst = dst; 1281 } 1282 1283 /* 1284 * Retrieve incoming source route for use in replies, 1285 * in the same form used by setsockopt. 1286 * The first hop is placed before the options, will be removed later. 1287 */ 1288 struct mbuf * 1289 ip_srcroute() 1290 { 1291 register struct in_addr *p, *q; 1292 register struct mbuf *m; 1293 1294 if (ip_nhops == 0) 1295 return ((struct mbuf *)0); 1296 m = m_get(M_DONTWAIT, MT_HEADER); 1297 if (m == 0) 1298 return ((struct mbuf *)0); 1299 1300 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1301 1302 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1303 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1304 OPTSIZ; 1305 #ifdef DIAGNOSTIC 1306 if (ipprintfs) 1307 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1308 #endif 1309 1310 /* 1311 * First save first hop for return route 1312 */ 1313 p = &ip_srcrt.route[ip_nhops - 1]; 1314 *(mtod(m, struct in_addr *)) = *p--; 1315 #ifdef DIAGNOSTIC 1316 if (ipprintfs) 1317 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1318 #endif 1319 1320 /* 1321 * Copy option fields and padding (nop) to mbuf. 1322 */ 1323 ip_srcrt.nop = IPOPT_NOP; 1324 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1325 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1326 &ip_srcrt.nop, OPTSIZ); 1327 q = (struct in_addr *)(mtod(m, caddr_t) + 1328 sizeof(struct in_addr) + OPTSIZ); 1329 #undef OPTSIZ 1330 /* 1331 * Record return path as an IP source route, 1332 * reversing the path (pointers are now aligned). 1333 */ 1334 while (p >= ip_srcrt.route) { 1335 #ifdef DIAGNOSTIC 1336 if (ipprintfs) 1337 printf(" %lx", (u_long)ntohl(q->s_addr)); 1338 #endif 1339 *q++ = *p--; 1340 } 1341 /* 1342 * Last hop goes to final destination. 1343 */ 1344 *q = ip_srcrt.dst; 1345 #ifdef DIAGNOSTIC 1346 if (ipprintfs) 1347 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1348 #endif 1349 return (m); 1350 } 1351 1352 /* 1353 * Strip out IP options, at higher 1354 * level protocol in the kernel. 1355 * Second argument is buffer to which options 1356 * will be moved, and return value is their length. 1357 * XXX should be deleted; last arg currently ignored. 1358 */ 1359 void 1360 ip_stripoptions(m, mopt) 1361 register struct mbuf *m; 1362 struct mbuf *mopt; 1363 { 1364 register int i; 1365 struct ip *ip = mtod(m, struct ip *); 1366 register caddr_t opts; 1367 int olen; 1368 1369 olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1370 opts = (caddr_t)(ip + 1); 1371 i = m->m_len - (sizeof (struct ip) + olen); 1372 bcopy(opts + olen, opts, (unsigned)i); 1373 m->m_len -= olen; 1374 if (m->m_flags & M_PKTHDR) 1375 m->m_pkthdr.len -= olen; 1376 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1377 } 1378 1379 u_char inetctlerrmap[PRC_NCMDS] = { 1380 0, 0, 0, 0, 1381 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1382 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1383 EMSGSIZE, EHOSTUNREACH, 0, 0, 1384 0, 0, 0, 0, 1385 ENOPROTOOPT 1386 }; 1387 1388 /* 1389 * Forward a packet. If some error occurs return the sender 1390 * an icmp packet. Note we can't always generate a meaningful 1391 * icmp message because icmp doesn't have a large enough repertoire 1392 * of codes and types. 1393 * 1394 * If not forwarding, just drop the packet. This could be confusing 1395 * if ipforwarding was zero but some routing protocol was advancing 1396 * us as a gateway to somewhere. However, we must let the routing 1397 * protocol deal with that. 1398 * 1399 * The srcrt parameter indicates whether the packet is being forwarded 1400 * via a source route. 1401 */ 1402 static void 1403 ip_forward(m, srcrt) 1404 struct mbuf *m; 1405 int srcrt; 1406 { 1407 register struct ip *ip = mtod(m, struct ip *); 1408 register struct sockaddr_in *sin; 1409 register struct rtentry *rt; 1410 int error, type = 0, code = 0; 1411 struct mbuf *mcopy; 1412 n_long dest; 1413 struct ifnet *destifp; 1414 1415 dest = 0; 1416 #ifdef DIAGNOSTIC 1417 if (ipprintfs) 1418 printf("forward: src %lx dst %lx ttl %x\n", 1419 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1420 ip->ip_ttl); 1421 #endif 1422 1423 1424 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1425 ipstat.ips_cantforward++; 1426 m_freem(m); 1427 return; 1428 } 1429 HTONS(ip->ip_id); 1430 #ifdef IPSTEALTH 1431 if (!ipstealth) { 1432 #endif 1433 if (ip->ip_ttl <= IPTTLDEC) { 1434 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1435 dest, 0); 1436 return; 1437 } 1438 ip->ip_ttl -= IPTTLDEC; 1439 #ifdef IPSTEALTH 1440 } 1441 #endif 1442 1443 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1444 if ((rt = ipforward_rt.ro_rt) == 0 || 1445 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1446 if (ipforward_rt.ro_rt) { 1447 RTFREE(ipforward_rt.ro_rt); 1448 ipforward_rt.ro_rt = 0; 1449 } 1450 sin->sin_family = AF_INET; 1451 sin->sin_len = sizeof(*sin); 1452 sin->sin_addr = ip->ip_dst; 1453 1454 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1455 if (ipforward_rt.ro_rt == 0) { 1456 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1457 return; 1458 } 1459 rt = ipforward_rt.ro_rt; 1460 } 1461 1462 /* 1463 * Save at most 64 bytes of the packet in case 1464 * we need to generate an ICMP message to the src. 1465 */ 1466 mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); 1467 1468 /* 1469 * If forwarding packet using same interface that it came in on, 1470 * perhaps should send a redirect to sender to shortcut a hop. 1471 * Only send redirect if source is sending directly to us, 1472 * and if packet was not source routed (or has any options). 1473 * Also, don't send redirect if forwarding using a default route 1474 * or a route modified by a redirect. 1475 */ 1476 #define satosin(sa) ((struct sockaddr_in *)(sa)) 1477 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1478 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1479 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1480 ipsendredirects && !srcrt) { 1481 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1482 u_long src = ntohl(ip->ip_src.s_addr); 1483 1484 if (RTA(rt) && 1485 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1486 if (rt->rt_flags & RTF_GATEWAY) 1487 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1488 else 1489 dest = ip->ip_dst.s_addr; 1490 /* Router requirements says to only send host redirects */ 1491 type = ICMP_REDIRECT; 1492 code = ICMP_REDIRECT_HOST; 1493 #ifdef DIAGNOSTIC 1494 if (ipprintfs) 1495 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1496 #endif 1497 } 1498 } 1499 1500 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1501 IP_FORWARDING, 0); 1502 if (error) 1503 ipstat.ips_cantforward++; 1504 else { 1505 ipstat.ips_forward++; 1506 if (type) 1507 ipstat.ips_redirectsent++; 1508 else { 1509 if (mcopy) { 1510 ipflow_create(&ipforward_rt, mcopy); 1511 m_freem(mcopy); 1512 } 1513 return; 1514 } 1515 } 1516 if (mcopy == NULL) 1517 return; 1518 destifp = NULL; 1519 1520 switch (error) { 1521 1522 case 0: /* forwarded, but need redirect */ 1523 /* type, code set above */ 1524 break; 1525 1526 case ENETUNREACH: /* shouldn't happen, checked above */ 1527 case EHOSTUNREACH: 1528 case ENETDOWN: 1529 case EHOSTDOWN: 1530 default: 1531 type = ICMP_UNREACH; 1532 code = ICMP_UNREACH_HOST; 1533 break; 1534 1535 case EMSGSIZE: 1536 type = ICMP_UNREACH; 1537 code = ICMP_UNREACH_NEEDFRAG; 1538 if (ipforward_rt.ro_rt) 1539 destifp = ipforward_rt.ro_rt->rt_ifp; 1540 ipstat.ips_cantfrag++; 1541 break; 1542 1543 case ENOBUFS: 1544 type = ICMP_SOURCEQUENCH; 1545 code = 0; 1546 break; 1547 } 1548 icmp_error(mcopy, type, code, dest, destifp); 1549 } 1550 1551 void 1552 ip_savecontrol(inp, mp, ip, m) 1553 register struct inpcb *inp; 1554 register struct mbuf **mp; 1555 register struct ip *ip; 1556 register struct mbuf *m; 1557 { 1558 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1559 struct timeval tv; 1560 1561 microtime(&tv); 1562 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1563 SCM_TIMESTAMP, SOL_SOCKET); 1564 if (*mp) 1565 mp = &(*mp)->m_next; 1566 } 1567 if (inp->inp_flags & INP_RECVDSTADDR) { 1568 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1569 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1570 if (*mp) 1571 mp = &(*mp)->m_next; 1572 } 1573 #ifdef notyet 1574 /* XXX 1575 * Moving these out of udp_input() made them even more broken 1576 * than they already were. 1577 */ 1578 /* options were tossed already */ 1579 if (inp->inp_flags & INP_RECVOPTS) { 1580 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1581 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1582 if (*mp) 1583 mp = &(*mp)->m_next; 1584 } 1585 /* ip_srcroute doesn't do what we want here, need to fix */ 1586 if (inp->inp_flags & INP_RECVRETOPTS) { 1587 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1588 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1589 if (*mp) 1590 mp = &(*mp)->m_next; 1591 } 1592 #endif 1593 if (inp->inp_flags & INP_RECVIF) { 1594 struct ifnet *ifp; 1595 struct sdlbuf { 1596 struct sockaddr_dl sdl; 1597 u_char pad[32]; 1598 } sdlbuf; 1599 struct sockaddr_dl *sdp; 1600 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1601 1602 if (((ifp = m->m_pkthdr.rcvif)) 1603 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1604 sdp = (struct sockaddr_dl *)(ifnet_addrs 1605 [ifp->if_index - 1]->ifa_addr); 1606 /* 1607 * Change our mind and don't try copy. 1608 */ 1609 if ((sdp->sdl_family != AF_LINK) 1610 || (sdp->sdl_len > sizeof(sdlbuf))) { 1611 goto makedummy; 1612 } 1613 bcopy(sdp, sdl2, sdp->sdl_len); 1614 } else { 1615 makedummy: 1616 sdl2->sdl_len 1617 = offsetof(struct sockaddr_dl, sdl_data[0]); 1618 sdl2->sdl_family = AF_LINK; 1619 sdl2->sdl_index = 0; 1620 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1621 } 1622 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1623 IP_RECVIF, IPPROTO_IP); 1624 if (*mp) 1625 mp = &(*mp)->m_next; 1626 } 1627 } 1628 1629 int 1630 ip_rsvp_init(struct socket *so) 1631 { 1632 if (so->so_type != SOCK_RAW || 1633 so->so_proto->pr_protocol != IPPROTO_RSVP) 1634 return EOPNOTSUPP; 1635 1636 if (ip_rsvpd != NULL) 1637 return EADDRINUSE; 1638 1639 ip_rsvpd = so; 1640 /* 1641 * This may seem silly, but we need to be sure we don't over-increment 1642 * the RSVP counter, in case something slips up. 1643 */ 1644 if (!ip_rsvp_on) { 1645 ip_rsvp_on = 1; 1646 rsvp_on++; 1647 } 1648 1649 return 0; 1650 } 1651 1652 int 1653 ip_rsvp_done(void) 1654 { 1655 ip_rsvpd = NULL; 1656 /* 1657 * This may seem silly, but we need to be sure we don't over-decrement 1658 * the RSVP counter, in case something slips up. 1659 */ 1660 if (ip_rsvp_on) { 1661 ip_rsvp_on = 0; 1662 rsvp_on--; 1663 } 1664 return 0; 1665 } 1666