Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netinet/ip_input.c
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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 * $FreeBSD$ 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_ipdn.h" 43 #include "opt_ipdivert.h" 44 #include "opt_ipfilter.h" 45 #include "opt_ipstealth.h" 46 47 #include <stddef.h> 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/mbuf.h> 52 #include <sys/malloc.h> 53 #include <sys/domain.h> 54 #include <sys/protosw.h> 55 #include <sys/socket.h> 56 #include <sys/time.h> 57 #include <sys/kernel.h> 58 #include <sys/syslog.h> 59 #include <sys/sysctl.h> 60 61 #include <net/if.h> 62 #include <net/if_var.h> 63 #include <net/if_dl.h> 64 #include <net/route.h> 65 #include <net/netisr.h> 66 67 #include <netinet/in.h> 68 #include <netinet/in_systm.h> 69 #include <netinet/in_var.h> 70 #include <netinet/ip.h> 71 #include <netinet/in_pcb.h> 72 #include <netinet/ip_var.h> 73 #include <netinet/ip_icmp.h> 74 #include <machine/in_cksum.h> 75 76 #include <sys/socketvar.h> 77 78 #ifdef IPFIREWALL 79 #include <netinet/ip_fw.h> 80 #endif 81 82 #ifdef DUMMYNET 83 #include <netinet/ip_dummynet.h> 84 #endif 85 86 int rsvp_on = 0; 87 static int ip_rsvp_on; 88 struct socket *ip_rsvpd; 89 90 int ipforwarding = 0; 91 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 92 &ipforwarding, 0, ""); 93 94 static int ipsendredirects = 1; /* XXX */ 95 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 96 &ipsendredirects, 0, ""); 97 98 int ip_defttl = IPDEFTTL; 99 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 100 &ip_defttl, 0, ""); 101 102 static int ip_dosourceroute = 0; 103 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 104 &ip_dosourceroute, 0, ""); 105 106 static int ip_acceptsourceroute = 0; 107 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 108 CTLFLAG_RW, &ip_acceptsourceroute, 0, ""); 109 #ifdef DIAGNOSTIC 110 static int ipprintfs = 0; 111 #endif 112 113 extern struct domain inetdomain; 114 extern struct protosw inetsw[]; 115 u_char ip_protox[IPPROTO_MAX]; 116 static int ipqmaxlen = IFQ_MAXLEN; 117 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 118 struct ifqueue ipintrq; 119 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RD, 120 &ipintrq.ifq_maxlen, 0, ""); 121 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 122 &ipintrq.ifq_drops, 0, ""); 123 124 struct ipstat ipstat; 125 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RD, 126 &ipstat, ipstat, ""); 127 128 /* Packet reassembly stuff */ 129 #define IPREASS_NHASH_LOG2 6 130 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 131 #define IPREASS_HMASK (IPREASS_NHASH - 1) 132 #define IPREASS_HASH(x,y) \ 133 ((((x) & 0xF | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 134 135 static struct ipq ipq[IPREASS_NHASH]; 136 static int nipq = 0; /* total # of reass queues */ 137 static int maxnipq; 138 139 #ifdef IPCTL_DEFMTU 140 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 141 &ip_mtu, 0, ""); 142 #endif 143 144 #ifdef IPSTEALTH 145 static int ipstealth = 0; 146 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 147 &ipstealth, 0, ""); 148 #endif 149 150 #if !defined(COMPAT_IPFW) || COMPAT_IPFW == 1 151 #undef COMPAT_IPFW 152 #define COMPAT_IPFW 1 153 #else 154 #undef COMPAT_IPFW 155 #endif 156 157 #ifdef COMPAT_IPFW 158 159 #include <netinet/ip_fw.h> 160 161 /* Firewall hooks */ 162 ip_fw_chk_t *ip_fw_chk_ptr; 163 ip_fw_ctl_t *ip_fw_ctl_ptr; 164 int fw_enable = 1 ; 165 166 #ifdef DUMMYNET 167 ip_dn_ctl_t *ip_dn_ctl_ptr; 168 #endif 169 170 #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 static int ip_nfragpackets = 0; 179 static int ip_maxfragpackets; /* initialized in ip_init() */ 180 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 181 &ip_maxfragpackets, 0, 182 "Maximum number of IPv4 fragment reassembly queue entries"); 183 184 /* 185 * We need to save the IP options in case a protocol wants to respond 186 * to an incoming packet over the same route if the packet got here 187 * using IP source routing. This allows connection establishment and 188 * maintenance when the remote end is on a network that is not known 189 * to us. 190 */ 191 static int ip_nhops = 0; 192 static struct ip_srcrt { 193 struct in_addr dst; /* final destination */ 194 char nop; /* one NOP to align */ 195 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 196 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 197 } ip_srcrt; 198 199 #ifdef IPDIVERT 200 /* 201 * Shared variable between ip_input() and ip_reass() to communicate 202 * about which packets, once assembled from fragments, get diverted, 203 * and to which port. 204 */ 205 static u_short frag_divert_port; 206 #endif 207 208 struct sockaddr_in *ip_fw_fwd_addr; 209 210 static void save_rte __P((u_char *, struct in_addr)); 211 static int ip_dooptions __P((struct mbuf *)); 212 static void ip_forward __P((struct mbuf *, int)); 213 static void ip_freef __P((struct ipq *)); 214 static struct ip * 215 ip_reass __P((struct mbuf *, struct ipq *, struct ipq *)); 216 static struct in_ifaddr * 217 ip_rtaddr __P((struct in_addr)); 218 static void ipintr __P((void)); 219 /* 220 * IP initialization: fill in IP protocol switch table. 221 * All protocols not implemented in kernel go to raw IP protocol handler. 222 */ 223 void 224 ip_init() 225 { 226 register struct protosw *pr; 227 register int i; 228 229 TAILQ_INIT(&in_ifaddrhead); 230 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 231 if (pr == 0) 232 panic("ip_init"); 233 for (i = 0; i < IPPROTO_MAX; i++) 234 ip_protox[i] = pr - inetsw; 235 for (pr = inetdomain.dom_protosw; 236 pr < inetdomain.dom_protoswNPROTOSW; pr++) 237 if (pr->pr_domain->dom_family == PF_INET && 238 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 239 ip_protox[pr->pr_protocol] = pr - inetsw; 240 241 for (i = 0; i < IPREASS_NHASH; i++) 242 ipq[i].next = ipq[i].prev = &ipq[i]; 243 244 maxnipq = nmbclusters / 4; 245 ip_maxfragpackets = nmbclusters / 4; 246 247 ip_id = time_second & 0xffff; 248 ipintrq.ifq_maxlen = ipqmaxlen; 249 #ifdef DUMMYNET 250 ip_dn_init(); 251 #endif 252 #ifdef IPNAT 253 ip_nat_init(); 254 #endif 255 #ifdef IPFILTER 256 iplattach(); 257 #endif 258 259 } 260 261 static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 262 static struct route ipforward_rt; 263 264 /* 265 * Ip input routine. Checksum and byte swap header. If fragmented 266 * try to reassemble. Process options. Pass to next level. 267 */ 268 void 269 ip_input(struct mbuf *m) 270 { 271 struct ip *ip; 272 struct ipq *fp; 273 struct in_ifaddr *ia; 274 int i, hlen, mff; 275 u_short sum; 276 #ifndef IPDIVERT /* dummy variable for the firewall code to play with */ 277 u_short ip_divert_cookie = 0 ; 278 #endif 279 #ifdef COMPAT_IPFW 280 struct ip_fw_chain *rule = NULL ; 281 #endif 282 283 #if defined(IPFIREWALL) && defined(DUMMYNET) 284 /* 285 * dummynet packet are prepended a vestigial mbuf with 286 * m_type = MT_DUMMYNET and m_data pointing to the matching 287 * rule. 288 */ 289 if (m->m_type == MT_DUMMYNET) { 290 rule = (struct ip_fw_chain *)(m->m_data) ; 291 m = m->m_next ; 292 ip = mtod(m, struct ip *); 293 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 294 goto iphack ; 295 } else 296 rule = NULL ; 297 #endif 298 299 #ifdef DIAGNOSTIC 300 if (m == NULL || (m->m_flags & M_PKTHDR) == 0) 301 panic("ip_input no HDR"); 302 #endif 303 /* 304 * If no IP addresses have been set yet but the interfaces 305 * are receiving, can't do anything with incoming packets yet. 306 * XXX This is broken! We should be able to receive broadcasts 307 * and multicasts even without any local addresses configured. 308 */ 309 if (TAILQ_EMPTY(&in_ifaddrhead)) 310 goto bad; 311 ipstat.ips_total++; 312 313 if (m->m_pkthdr.len < sizeof(struct ip)) 314 goto tooshort; 315 316 if (m->m_len < sizeof (struct ip) && 317 (m = m_pullup(m, sizeof (struct ip))) == 0) { 318 ipstat.ips_toosmall++; 319 return; 320 } 321 ip = mtod(m, struct ip *); 322 323 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 324 ipstat.ips_badvers++; 325 goto bad; 326 } 327 328 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 329 if (hlen < sizeof(struct ip)) { /* minimum header length */ 330 ipstat.ips_badhlen++; 331 goto bad; 332 } 333 if (hlen > m->m_len) { 334 if ((m = m_pullup(m, hlen)) == 0) { 335 ipstat.ips_badhlen++; 336 return; 337 } 338 ip = mtod(m, struct ip *); 339 } 340 if (hlen == sizeof(struct ip)) { 341 sum = in_cksum_hdr(ip); 342 } else { 343 sum = in_cksum(m, hlen); 344 } 345 if (sum) { 346 ipstat.ips_badsum++; 347 goto bad; 348 } 349 350 /* 351 * Convert fields to host representation. 352 */ 353 NTOHS(ip->ip_len); 354 if (ip->ip_len < hlen) { 355 ipstat.ips_badlen++; 356 goto bad; 357 } 358 NTOHS(ip->ip_id); 359 NTOHS(ip->ip_off); 360 361 /* 362 * Check that the amount of data in the buffers 363 * is as at least much as the IP header would have us expect. 364 * Trim mbufs if longer than we expect. 365 * Drop packet if shorter than we expect. 366 */ 367 if (m->m_pkthdr.len < ip->ip_len) { 368 tooshort: 369 ipstat.ips_tooshort++; 370 goto bad; 371 } 372 if (m->m_pkthdr.len > ip->ip_len) { 373 if (m->m_len == m->m_pkthdr.len) { 374 m->m_len = ip->ip_len; 375 m->m_pkthdr.len = ip->ip_len; 376 } else 377 m_adj(m, ip->ip_len - m->m_pkthdr.len); 378 } 379 /* 380 * IpHack's section. 381 * Right now when no processing on packet has done 382 * and it is still fresh out of network we do our black 383 * deals with it. 384 * - Firewall: deny/allow/divert 385 * - Xlate: translate packet's addr/port (NAT). 386 * - Pipe: pass pkt through dummynet. 387 * - Wrap: fake packet's addr/port <unimpl.> 388 * - Encapsulate: put it in another IP and send out. <unimp.> 389 */ 390 391 #if defined(IPFIREWALL) && defined(DUMMYNET) 392 iphack: 393 #endif 394 #if defined(IPFILTER) || defined(IPFILTER_LKM) 395 /* 396 * Check if we want to allow this packet to be processed. 397 * Consider it to be bad if not. 398 */ 399 if (fr_checkp) { 400 struct mbuf *m1 = m; 401 402 if ((*fr_checkp)(ip, hlen, m->m_pkthdr.rcvif, 0, &m1) || !m1) 403 return; 404 ip = mtod(m = m1, struct ip *); 405 } 406 #endif 407 #ifdef COMPAT_IPFW 408 if (fw_enable && ip_fw_chk_ptr) { 409 #ifdef IPFIREWALL_FORWARD 410 /* 411 * If we've been forwarded from the output side, then 412 * skip the firewall a second time 413 */ 414 if (ip_fw_fwd_addr) 415 goto ours; 416 #endif /* IPFIREWALL_FORWARD */ 417 i = (*ip_fw_chk_ptr)(&ip, hlen, NULL, &ip_divert_cookie, 418 &m, &rule, &ip_fw_fwd_addr); 419 /* 420 * see the comment in ip_output for the return values 421 * produced by the firewall. 422 */ 423 if (!m) /* packet discarded by firewall */ 424 return ; 425 if (i == 0 && ip_fw_fwd_addr == NULL) /* common case */ 426 goto pass ; 427 #ifdef DUMMYNET 428 if (i & 0x10000) { 429 /* send packet to the appropriate pipe */ 430 dummynet_io(i&0xffff,DN_TO_IP_IN,m,NULL,NULL,0, rule); 431 return ; 432 } 433 #endif 434 #ifdef IPDIVERT 435 if (i > 0 && i < 0x10000) { 436 /* Divert packet */ 437 frag_divert_port = i & 0xffff ; 438 goto ours; 439 } 440 #endif 441 #ifdef IPFIREWALL_FORWARD 442 if (i == 0 && ip_fw_fwd_addr != NULL) 443 goto pass ; 444 #endif 445 /* 446 * if we get here, the packet must be dropped 447 */ 448 m_freem(m); 449 return; 450 } 451 pass: 452 453 #endif /* !COMPAT_IPFW */ 454 455 /* 456 * Process options and, if not destined for us, 457 * ship it on. ip_dooptions returns 1 when an 458 * error was detected (causing an icmp message 459 * to be sent and the original packet to be freed). 460 */ 461 ip_nhops = 0; /* for source routed packets */ 462 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 463 #ifdef IPFIREWALL_FORWARD 464 ip_fw_fwd_addr = NULL; 465 #endif 466 return; 467 } 468 469 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 470 * matter if it is destined to another node, or whether it is 471 * a multicast one, RSVP wants it! and prevents it from being forwarded 472 * anywhere else. Also checks if the rsvp daemon is running before 473 * grabbing the packet. 474 */ 475 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 476 goto ours; 477 478 /* 479 * Check our list of addresses, to see if the packet is for us. 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 /* 777 * Enforce upper bound on number of fragmented packets 778 * for which we attempt reassembly; 779 * If maxfrag is 0, never accept fragments. 780 * If maxfrag is -1, accept all fragments without limitation. 781 */ 782 if ((ip_maxfragpackets >= 0) && (ip_nfragpackets >= ip_maxfragpackets)) 783 goto dropfrag; 784 ip_nfragpackets++; 785 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 786 goto dropfrag; 787 fp = mtod(t, struct ipq *); 788 insque(fp, where); 789 nipq++; 790 fp->ipq_ttl = IPFRAGTTL; 791 fp->ipq_p = ip->ip_p; 792 fp->ipq_id = ip->ip_id; 793 fp->ipq_src = ip->ip_src; 794 fp->ipq_dst = ip->ip_dst; 795 fp->ipq_frags = m; 796 m->m_nextpkt = NULL; 797 #ifdef IPDIVERT 798 fp->ipq_divert = 0; 799 fp->ipq_div_cookie = 0; 800 #endif 801 goto inserted; 802 } 803 804 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 805 806 /* 807 * Find a segment which begins after this one does. 808 */ 809 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 810 if (GETIP(q)->ip_off > ip->ip_off) 811 break; 812 813 /* 814 * If there is a preceding segment, it may provide some of 815 * our data already. If so, drop the data from the incoming 816 * segment. If it provides all of our data, drop us, otherwise 817 * stick new segment in the proper place. 818 */ 819 if (p) { 820 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 821 if (i > 0) { 822 if (i >= ip->ip_len) 823 goto dropfrag; 824 m_adj(dtom(ip), i); 825 ip->ip_off += i; 826 ip->ip_len -= i; 827 } 828 m->m_nextpkt = p->m_nextpkt; 829 p->m_nextpkt = m; 830 } else { 831 m->m_nextpkt = fp->ipq_frags; 832 fp->ipq_frags = m; 833 } 834 835 /* 836 * While we overlap succeeding segments trim them or, 837 * if they are completely covered, dequeue them. 838 */ 839 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 840 q = nq) { 841 i = (ip->ip_off + ip->ip_len) - 842 GETIP(q)->ip_off; 843 if (i < GETIP(q)->ip_len) { 844 GETIP(q)->ip_len -= i; 845 GETIP(q)->ip_off += i; 846 m_adj(q, i); 847 break; 848 } 849 nq = q->m_nextpkt; 850 m->m_nextpkt = nq; 851 m_freem(q); 852 } 853 854 inserted: 855 856 #ifdef IPDIVERT 857 /* 858 * Any fragment diverting causes the whole packet to divert 859 */ 860 if (frag_divert_port) { 861 fp->ipq_divert = frag_divert_port; 862 fp->ipq_div_cookie = ip_divert_cookie; 863 } 864 frag_divert_port = 0; 865 ip_divert_cookie = 0; 866 #endif 867 868 /* 869 * Check for complete reassembly. 870 */ 871 next = 0; 872 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 873 if (GETIP(q)->ip_off != next) 874 return (0); 875 next += GETIP(q)->ip_len; 876 } 877 /* Make sure the last packet didn't have the IP_MF flag */ 878 if (p->m_flags & M_FRAG) 879 return (0); 880 881 /* 882 * Reassembly is complete. Make sure the packet is a sane size. 883 */ 884 q = fp->ipq_frags; 885 ip = GETIP(q); 886 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 887 ipstat.ips_toolong++; 888 ip_freef(fp); 889 return (0); 890 } 891 892 /* 893 * Concatenate fragments. 894 */ 895 m = q; 896 t = m->m_next; 897 m->m_next = 0; 898 m_cat(m, t); 899 nq = q->m_nextpkt; 900 q->m_nextpkt = 0; 901 for (q = nq; q != NULL; q = nq) { 902 nq = q->m_nextpkt; 903 q->m_nextpkt = NULL; 904 m_cat(m, q); 905 } 906 907 #ifdef IPDIVERT 908 /* 909 * extract divert port for packet, if any 910 */ 911 frag_divert_port = fp->ipq_divert; 912 ip_divert_cookie = fp->ipq_div_cookie; 913 #endif 914 915 /* 916 * Create header for new ip packet by 917 * modifying header of first packet; 918 * dequeue and discard fragment reassembly header. 919 * Make header visible. 920 */ 921 ip->ip_len = next; 922 ip->ip_src = fp->ipq_src; 923 ip->ip_dst = fp->ipq_dst; 924 remque(fp); 925 nipq--; 926 (void) m_free(dtom(fp)); 927 ip_nfragpackets--; 928 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 929 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 930 /* some debugging cruft by sklower, below, will go away soon */ 931 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 932 register int plen = 0; 933 for (t = m; m; m = m->m_next) 934 plen += m->m_len; 935 t->m_pkthdr.len = plen; 936 } 937 return (ip); 938 939 dropfrag: 940 #ifdef IPDIVERT 941 frag_divert_port = 0; 942 ip_divert_cookie = 0; 943 #endif 944 ipstat.ips_fragdropped++; 945 m_freem(m); 946 return (0); 947 948 #undef GETIP 949 } 950 951 /* 952 * Free a fragment reassembly header and all 953 * associated datagrams. 954 */ 955 static void 956 ip_freef(fp) 957 struct ipq *fp; 958 { 959 register struct mbuf *q; 960 961 while (fp->ipq_frags) { 962 q = fp->ipq_frags; 963 fp->ipq_frags = q->m_nextpkt; 964 m_freem(q); 965 } 966 remque(fp); 967 (void) m_free(dtom(fp)); 968 ip_nfragpackets--; 969 nipq--; 970 } 971 972 /* 973 * IP timer processing; 974 * if a timer expires on a reassembly 975 * queue, discard it. 976 */ 977 void 978 ip_slowtimo() 979 { 980 register struct ipq *fp; 981 int s = splnet(); 982 int i; 983 984 for (i = 0; i < IPREASS_NHASH; i++) { 985 fp = ipq[i].next; 986 if (fp == 0) 987 continue; 988 while (fp != &ipq[i]) { 989 --fp->ipq_ttl; 990 fp = fp->next; 991 if (fp->prev->ipq_ttl == 0) { 992 ipstat.ips_fragtimeout++; 993 ip_freef(fp->prev); 994 } 995 } 996 } 997 /* 998 * If we are over the maximum number of fragments 999 * (due to the limit being lowered), drain off 1000 * enough to get down to the new limit. 1001 */ 1002 for (i = 0; i < IPREASS_NHASH; i++) { 1003 if (ip_maxfragpackets >= 0) { 1004 while ((ip_nfragpackets > ip_maxfragpackets) && 1005 (ipq[i].next != &ipq[i])) { 1006 ipstat.ips_fragdropped++; 1007 ip_freef(ipq[i].next); 1008 } 1009 } 1010 } 1011 ipflow_slowtimo(); 1012 splx(s); 1013 } 1014 1015 /* 1016 * Drain off all datagram fragments. 1017 */ 1018 void 1019 ip_drain() 1020 { 1021 int i; 1022 1023 for (i = 0; i < IPREASS_NHASH; i++) { 1024 while (ipq[i].next != &ipq[i]) { 1025 ipstat.ips_fragdropped++; 1026 ip_freef(ipq[i].next); 1027 } 1028 } 1029 in_rtqdrain(); 1030 } 1031 1032 /* 1033 * Do option processing on a datagram, 1034 * possibly discarding it if bad options are encountered, 1035 * or forwarding it if source-routed. 1036 * Returns 1 if packet has been forwarded/freed, 1037 * 0 if the packet should be processed further. 1038 */ 1039 static int 1040 ip_dooptions(m) 1041 struct mbuf *m; 1042 { 1043 register struct ip *ip = mtod(m, struct ip *); 1044 register u_char *cp; 1045 register struct ip_timestamp *ipt; 1046 register struct in_ifaddr *ia; 1047 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1048 struct in_addr *sin, dst; 1049 n_time ntime; 1050 1051 dst = ip->ip_dst; 1052 cp = (u_char *)(ip + 1); 1053 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1054 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1055 opt = cp[IPOPT_OPTVAL]; 1056 if (opt == IPOPT_EOL) 1057 break; 1058 if (opt == IPOPT_NOP) 1059 optlen = 1; 1060 else { 1061 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1062 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1063 goto bad; 1064 } 1065 optlen = cp[IPOPT_OLEN]; 1066 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1067 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1068 goto bad; 1069 } 1070 } 1071 switch (opt) { 1072 1073 default: 1074 break; 1075 1076 /* 1077 * Source routing with record. 1078 * Find interface with current destination address. 1079 * If none on this machine then drop if strictly routed, 1080 * or do nothing if loosely routed. 1081 * Record interface address and bring up next address 1082 * component. If strictly routed make sure next 1083 * address is on directly accessible net. 1084 */ 1085 case IPOPT_LSRR: 1086 case IPOPT_SSRR: 1087 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1088 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1089 goto bad; 1090 } 1091 ipaddr.sin_addr = ip->ip_dst; 1092 ia = (struct in_ifaddr *) 1093 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1094 if (ia == 0) { 1095 if (opt == IPOPT_SSRR) { 1096 type = ICMP_UNREACH; 1097 code = ICMP_UNREACH_SRCFAIL; 1098 goto bad; 1099 } 1100 if (!ip_dosourceroute) 1101 goto nosourcerouting; 1102 /* 1103 * Loose routing, and not at next destination 1104 * yet; nothing to do except forward. 1105 */ 1106 break; 1107 } 1108 off--; /* 0 origin */ 1109 if (off > optlen - (int)sizeof(struct in_addr)) { 1110 /* 1111 * End of source route. Should be for us. 1112 */ 1113 if (!ip_acceptsourceroute) 1114 goto nosourcerouting; 1115 save_rte(cp, ip->ip_src); 1116 break; 1117 } 1118 1119 if (!ip_dosourceroute) { 1120 if (ipforwarding) { 1121 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1122 /* 1123 * Acting as a router, so generate ICMP 1124 */ 1125 nosourcerouting: 1126 strcpy(buf, inet_ntoa(ip->ip_dst)); 1127 log(LOG_WARNING, 1128 "attempted source route from %s to %s\n", 1129 inet_ntoa(ip->ip_src), buf); 1130 type = ICMP_UNREACH; 1131 code = ICMP_UNREACH_SRCFAIL; 1132 goto bad; 1133 } else { 1134 /* 1135 * Not acting as a router, so silently drop. 1136 */ 1137 ipstat.ips_cantforward++; 1138 m_freem(m); 1139 return (1); 1140 } 1141 } 1142 1143 /* 1144 * locate outgoing interface 1145 */ 1146 (void)memcpy(&ipaddr.sin_addr, cp + off, 1147 sizeof(ipaddr.sin_addr)); 1148 1149 if (opt == IPOPT_SSRR) { 1150 #define INA struct in_ifaddr * 1151 #define SA struct sockaddr * 1152 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1153 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1154 } else 1155 ia = ip_rtaddr(ipaddr.sin_addr); 1156 if (ia == 0) { 1157 type = ICMP_UNREACH; 1158 code = ICMP_UNREACH_SRCFAIL; 1159 goto bad; 1160 } 1161 ip->ip_dst = ipaddr.sin_addr; 1162 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1163 sizeof(struct in_addr)); 1164 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1165 /* 1166 * Let ip_intr's mcast routing check handle mcast pkts 1167 */ 1168 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1169 break; 1170 1171 case IPOPT_RR: 1172 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1173 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1174 goto bad; 1175 } 1176 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1177 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1178 goto bad; 1179 } 1180 /* 1181 * If no space remains, ignore. 1182 */ 1183 off--; /* 0 origin */ 1184 if (off > optlen - (int)sizeof(struct in_addr)) 1185 break; 1186 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1187 sizeof(ipaddr.sin_addr)); 1188 /* 1189 * locate outgoing interface; if we're the destination, 1190 * use the incoming interface (should be same). 1191 */ 1192 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1193 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1194 type = ICMP_UNREACH; 1195 code = ICMP_UNREACH_HOST; 1196 goto bad; 1197 } 1198 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1199 sizeof(struct in_addr)); 1200 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1201 break; 1202 1203 case IPOPT_TS: 1204 code = cp - (u_char *)ip; 1205 ipt = (struct ip_timestamp *)cp; 1206 if (ipt->ipt_len < 5) 1207 goto bad; 1208 if (ipt->ipt_ptr > 1209 ipt->ipt_len - (int)sizeof(int32_t)) { 1210 if (++ipt->ipt_oflw == 0) 1211 goto bad; 1212 break; 1213 } 1214 sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); 1215 switch (ipt->ipt_flg) { 1216 1217 case IPOPT_TS_TSONLY: 1218 break; 1219 1220 case IPOPT_TS_TSANDADDR: 1221 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1222 sizeof(struct in_addr) > ipt->ipt_len) 1223 goto bad; 1224 ipaddr.sin_addr = dst; 1225 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1226 m->m_pkthdr.rcvif); 1227 if (ia == 0) 1228 continue; 1229 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1230 sizeof(struct in_addr)); 1231 ipt->ipt_ptr += sizeof(struct in_addr); 1232 break; 1233 1234 case IPOPT_TS_PRESPEC: 1235 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1236 sizeof(struct in_addr) > ipt->ipt_len) 1237 goto bad; 1238 (void)memcpy(&ipaddr.sin_addr, sin, 1239 sizeof(struct in_addr)); 1240 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1241 continue; 1242 ipt->ipt_ptr += sizeof(struct in_addr); 1243 break; 1244 1245 default: 1246 goto bad; 1247 } 1248 ntime = iptime(); 1249 (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime, 1250 sizeof(n_time)); 1251 ipt->ipt_ptr += sizeof(n_time); 1252 } 1253 } 1254 if (forward && ipforwarding) { 1255 ip_forward(m, 1); 1256 return (1); 1257 } 1258 return (0); 1259 bad: 1260 ip->ip_len -= IP_VHL_HL(ip->ip_vhl) << 2; /* XXX icmp_error adds in hdr length */ 1261 icmp_error(m, type, code, 0, 0); 1262 ipstat.ips_badoptions++; 1263 return (1); 1264 } 1265 1266 /* 1267 * Given address of next destination (final or next hop), 1268 * return internet address info of interface to be used to get there. 1269 */ 1270 static struct in_ifaddr * 1271 ip_rtaddr(dst) 1272 struct in_addr dst; 1273 { 1274 register struct sockaddr_in *sin; 1275 1276 sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; 1277 1278 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 1279 if (ipforward_rt.ro_rt) { 1280 RTFREE(ipforward_rt.ro_rt); 1281 ipforward_rt.ro_rt = 0; 1282 } 1283 sin->sin_family = AF_INET; 1284 sin->sin_len = sizeof(*sin); 1285 sin->sin_addr = dst; 1286 1287 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1288 } 1289 if (ipforward_rt.ro_rt == 0) 1290 return ((struct in_ifaddr *)0); 1291 return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); 1292 } 1293 1294 /* 1295 * Save incoming source route for use in replies, 1296 * to be picked up later by ip_srcroute if the receiver is interested. 1297 */ 1298 void 1299 save_rte(option, dst) 1300 u_char *option; 1301 struct in_addr dst; 1302 { 1303 unsigned olen; 1304 1305 olen = option[IPOPT_OLEN]; 1306 #ifdef DIAGNOSTIC 1307 if (ipprintfs) 1308 printf("save_rte: olen %d\n", olen); 1309 #endif 1310 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1311 return; 1312 bcopy(option, ip_srcrt.srcopt, olen); 1313 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1314 ip_srcrt.dst = dst; 1315 } 1316 1317 /* 1318 * Retrieve incoming source route for use in replies, 1319 * in the same form used by setsockopt. 1320 * The first hop is placed before the options, will be removed later. 1321 */ 1322 struct mbuf * 1323 ip_srcroute() 1324 { 1325 register struct in_addr *p, *q; 1326 register struct mbuf *m; 1327 1328 if (ip_nhops == 0) 1329 return ((struct mbuf *)0); 1330 m = m_get(M_DONTWAIT, MT_HEADER); 1331 if (m == 0) 1332 return ((struct mbuf *)0); 1333 1334 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1335 1336 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1337 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1338 OPTSIZ; 1339 #ifdef DIAGNOSTIC 1340 if (ipprintfs) 1341 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1342 #endif 1343 1344 /* 1345 * First save first hop for return route 1346 */ 1347 p = &ip_srcrt.route[ip_nhops - 1]; 1348 *(mtod(m, struct in_addr *)) = *p--; 1349 #ifdef DIAGNOSTIC 1350 if (ipprintfs) 1351 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1352 #endif 1353 1354 /* 1355 * Copy option fields and padding (nop) to mbuf. 1356 */ 1357 ip_srcrt.nop = IPOPT_NOP; 1358 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1359 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1360 &ip_srcrt.nop, OPTSIZ); 1361 q = (struct in_addr *)(mtod(m, caddr_t) + 1362 sizeof(struct in_addr) + OPTSIZ); 1363 #undef OPTSIZ 1364 /* 1365 * Record return path as an IP source route, 1366 * reversing the path (pointers are now aligned). 1367 */ 1368 while (p >= ip_srcrt.route) { 1369 #ifdef DIAGNOSTIC 1370 if (ipprintfs) 1371 printf(" %lx", (u_long)ntohl(q->s_addr)); 1372 #endif 1373 *q++ = *p--; 1374 } 1375 /* 1376 * Last hop goes to final destination. 1377 */ 1378 *q = ip_srcrt.dst; 1379 #ifdef DIAGNOSTIC 1380 if (ipprintfs) 1381 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1382 #endif 1383 return (m); 1384 } 1385 1386 /* 1387 * Strip out IP options, at higher 1388 * level protocol in the kernel. 1389 * Second argument is buffer to which options 1390 * will be moved, and return value is their length. 1391 * XXX should be deleted; last arg currently ignored. 1392 */ 1393 void 1394 ip_stripoptions(m, mopt) 1395 register struct mbuf *m; 1396 struct mbuf *mopt; 1397 { 1398 register int i; 1399 struct ip *ip = mtod(m, struct ip *); 1400 register caddr_t opts; 1401 int olen; 1402 1403 olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1404 opts = (caddr_t)(ip + 1); 1405 i = m->m_len - (sizeof (struct ip) + olen); 1406 bcopy(opts + olen, opts, (unsigned)i); 1407 m->m_len -= olen; 1408 if (m->m_flags & M_PKTHDR) 1409 m->m_pkthdr.len -= olen; 1410 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1411 } 1412 1413 u_char inetctlerrmap[PRC_NCMDS] = { 1414 0, 0, 0, 0, 1415 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1416 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1417 EMSGSIZE, EHOSTUNREACH, 0, 0, 1418 0, 0, 0, 0, 1419 ENOPROTOOPT 1420 }; 1421 1422 /* 1423 * Forward a packet. If some error occurs return the sender 1424 * an icmp packet. Note we can't always generate a meaningful 1425 * icmp message because icmp doesn't have a large enough repertoire 1426 * of codes and types. 1427 * 1428 * If not forwarding, just drop the packet. This could be confusing 1429 * if ipforwarding was zero but some routing protocol was advancing 1430 * us as a gateway to somewhere. However, we must let the routing 1431 * protocol deal with that. 1432 * 1433 * The srcrt parameter indicates whether the packet is being forwarded 1434 * via a source route. 1435 */ 1436 static void 1437 ip_forward(m, srcrt) 1438 struct mbuf *m; 1439 int srcrt; 1440 { 1441 register struct ip *ip = mtod(m, struct ip *); 1442 register struct sockaddr_in *sin; 1443 register struct rtentry *rt; 1444 int error, type = 0, code = 0; 1445 struct mbuf *mcopy; 1446 n_long dest; 1447 struct ifnet *destifp; 1448 1449 dest = 0; 1450 #ifdef DIAGNOSTIC 1451 if (ipprintfs) 1452 printf("forward: src %lx dst %lx ttl %x\n", 1453 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1454 ip->ip_ttl); 1455 #endif 1456 1457 1458 if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) { 1459 ipstat.ips_cantforward++; 1460 m_freem(m); 1461 return; 1462 } 1463 HTONS(ip->ip_id); 1464 #ifdef IPSTEALTH 1465 if (!ipstealth) { 1466 #endif 1467 if (ip->ip_ttl <= IPTTLDEC) { 1468 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1469 dest, 0); 1470 return; 1471 } 1472 ip->ip_ttl -= IPTTLDEC; 1473 #ifdef IPSTEALTH 1474 } 1475 #endif 1476 1477 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1478 if ((rt = ipforward_rt.ro_rt) == 0 || 1479 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1480 if (ipforward_rt.ro_rt) { 1481 RTFREE(ipforward_rt.ro_rt); 1482 ipforward_rt.ro_rt = 0; 1483 } 1484 sin->sin_family = AF_INET; 1485 sin->sin_len = sizeof(*sin); 1486 sin->sin_addr = ip->ip_dst; 1487 1488 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1489 if (ipforward_rt.ro_rt == 0) { 1490 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1491 return; 1492 } 1493 rt = ipforward_rt.ro_rt; 1494 } 1495 1496 /* 1497 * Save at most 64 bytes of the packet in case 1498 * we need to generate an ICMP message to the src. 1499 */ 1500 mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); 1501 1502 /* 1503 * If forwarding packet using same interface that it came in on, 1504 * perhaps should send a redirect to sender to shortcut a hop. 1505 * Only send redirect if source is sending directly to us, 1506 * and if packet was not source routed (or has any options). 1507 * Also, don't send redirect if forwarding using a default route 1508 * or a route modified by a redirect. 1509 */ 1510 #define satosin(sa) ((struct sockaddr_in *)(sa)) 1511 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1512 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1513 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1514 ipsendredirects && !srcrt) { 1515 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1516 u_long src = ntohl(ip->ip_src.s_addr); 1517 1518 if (RTA(rt) && 1519 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1520 if (rt->rt_flags & RTF_GATEWAY) 1521 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1522 else 1523 dest = ip->ip_dst.s_addr; 1524 /* Router requirements says to only send host redirects */ 1525 type = ICMP_REDIRECT; 1526 code = ICMP_REDIRECT_HOST; 1527 #ifdef DIAGNOSTIC 1528 if (ipprintfs) 1529 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1530 #endif 1531 } 1532 } 1533 1534 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1535 IP_FORWARDING, 0); 1536 if (error) 1537 ipstat.ips_cantforward++; 1538 else { 1539 ipstat.ips_forward++; 1540 if (type) 1541 ipstat.ips_redirectsent++; 1542 else { 1543 if (mcopy) { 1544 ipflow_create(&ipforward_rt, mcopy); 1545 m_freem(mcopy); 1546 } 1547 return; 1548 } 1549 } 1550 if (mcopy == NULL) 1551 return; 1552 destifp = NULL; 1553 1554 switch (error) { 1555 1556 case 0: /* forwarded, but need redirect */ 1557 /* type, code set above */ 1558 break; 1559 1560 case ENETUNREACH: /* shouldn't happen, checked above */ 1561 case EHOSTUNREACH: 1562 case ENETDOWN: 1563 case EHOSTDOWN: 1564 default: 1565 type = ICMP_UNREACH; 1566 code = ICMP_UNREACH_HOST; 1567 break; 1568 1569 case EMSGSIZE: 1570 type = ICMP_UNREACH; 1571 code = ICMP_UNREACH_NEEDFRAG; 1572 if (ipforward_rt.ro_rt) 1573 destifp = ipforward_rt.ro_rt->rt_ifp; 1574 ipstat.ips_cantfrag++; 1575 break; 1576 1577 case ENOBUFS: 1578 type = ICMP_SOURCEQUENCH; 1579 code = 0; 1580 break; 1581 1582 case EACCES: /* ipfw denied packet */ 1583 m_freem(mcopy); 1584 return; 1585 } 1586 icmp_error(mcopy, type, code, dest, destifp); 1587 } 1588 1589 void 1590 ip_savecontrol(inp, mp, ip, m) 1591 register struct inpcb *inp; 1592 register struct mbuf **mp; 1593 register struct ip *ip; 1594 register struct mbuf *m; 1595 { 1596 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1597 struct timeval tv; 1598 1599 microtime(&tv); 1600 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1601 SCM_TIMESTAMP, SOL_SOCKET); 1602 if (*mp) 1603 mp = &(*mp)->m_next; 1604 } 1605 if (inp->inp_flags & INP_RECVDSTADDR) { 1606 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1607 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1608 if (*mp) 1609 mp = &(*mp)->m_next; 1610 } 1611 #ifdef notyet 1612 /* XXX 1613 * Moving these out of udp_input() made them even more broken 1614 * than they already were. 1615 */ 1616 /* options were tossed already */ 1617 if (inp->inp_flags & INP_RECVOPTS) { 1618 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1619 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1620 if (*mp) 1621 mp = &(*mp)->m_next; 1622 } 1623 /* ip_srcroute doesn't do what we want here, need to fix */ 1624 if (inp->inp_flags & INP_RECVRETOPTS) { 1625 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1626 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1627 if (*mp) 1628 mp = &(*mp)->m_next; 1629 } 1630 #endif 1631 if (inp->inp_flags & INP_RECVIF) { 1632 struct ifnet *ifp; 1633 struct sdlbuf { 1634 struct sockaddr_dl sdl; 1635 u_char pad[32]; 1636 } sdlbuf; 1637 struct sockaddr_dl *sdp; 1638 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1639 1640 if (((ifp = m->m_pkthdr.rcvif)) 1641 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1642 sdp = (struct sockaddr_dl *)(ifnet_addrs 1643 [ifp->if_index - 1]->ifa_addr); 1644 /* 1645 * Change our mind and don't try copy. 1646 */ 1647 if ((sdp->sdl_family != AF_LINK) 1648 || (sdp->sdl_len > sizeof(sdlbuf))) { 1649 goto makedummy; 1650 } 1651 bcopy(sdp, sdl2, sdp->sdl_len); 1652 } else { 1653 makedummy: 1654 sdl2->sdl_len 1655 = offsetof(struct sockaddr_dl, sdl_data[0]); 1656 sdl2->sdl_family = AF_LINK; 1657 sdl2->sdl_index = 0; 1658 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1659 } 1660 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1661 IP_RECVIF, IPPROTO_IP); 1662 if (*mp) 1663 mp = &(*mp)->m_next; 1664 } 1665 } 1666 1667 int 1668 ip_rsvp_init(struct socket *so) 1669 { 1670 if (so->so_type != SOCK_RAW || 1671 so->so_proto->pr_protocol != IPPROTO_RSVP) 1672 return EOPNOTSUPP; 1673 1674 if (ip_rsvpd != NULL) 1675 return EADDRINUSE; 1676 1677 ip_rsvpd = so; 1678 /* 1679 * This may seem silly, but we need to be sure we don't over-increment 1680 * the RSVP counter, in case something slips up. 1681 */ 1682 if (!ip_rsvp_on) { 1683 ip_rsvp_on = 1; 1684 rsvp_on++; 1685 } 1686 1687 return 0; 1688 } 1689 1690 int 1691 ip_rsvp_done(void) 1692 { 1693 ip_rsvpd = NULL; 1694 /* 1695 * This may seem silly, but we need to be sure we don't over-decrement 1696 * the RSVP counter, in case something slips up. 1697 */ 1698 if (ip_rsvp_on) { 1699 ip_rsvp_on = 0; 1700 rsvp_on--; 1701 } 1702 return 0; 1703 }
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