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 */ 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 #include "opt_ipstealth.h" 45 #include "opt_ipsec.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 #include <net/intrq.h> 67 68 #include <netinet/in.h> 69 #include <netinet/in_systm.h> 70 #include <netinet/in_var.h> 71 #include <netinet/ip.h> 72 #include <netinet/in_pcb.h> 73 #include <netinet/ip_var.h> 74 #include <netinet/ip_icmp.h> 75 #include <machine/in_cksum.h> 76 77 #include <netinet/ipprotosw.h> 78 79 #include <sys/socketvar.h> 80 81 #include <netinet/ip_fw.h> 82 83 #ifdef IPSEC 84 #include <netinet6/ipsec.h> 85 #include <netkey/key.h> 86 #ifdef IPSEC_DEBUG 87 #include <netkey/key_debug.h> 88 #else 89 #define KEYDEBUG(lev,arg) 90 #endif 91 #endif 92 93 #include "faith.h" 94 #if defined(NFAITH) && NFAITH > 0 95 #include <net/if_types.h> 96 #endif 97 98 #ifdef DUMMYNET 99 #include <netinet/ip_dummynet.h> 100 #endif 101 102 int rsvp_on = 0; 103 static int ip_rsvp_on; 104 struct socket *ip_rsvpd; 105 106 int ipforwarding = 0; 107 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 108 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 109 110 static int ipsendredirects = 1; /* XXX */ 111 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 112 &ipsendredirects, 0, "Enable sending IP redirects"); 113 114 int ip_defttl = IPDEFTTL; 115 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 116 &ip_defttl, 0, "Maximum TTL on IP packets"); 117 118 static int ip_dosourceroute = 0; 119 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 120 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 121 122 static int ip_acceptsourceroute = 0; 123 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 124 CTLFLAG_RW, &ip_acceptsourceroute, 0, 125 "Enable accepting source routed IP packets"); 126 127 static int ip_keepfaith = 0; 128 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 129 &ip_keepfaith, 0, 130 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 131 132 #ifdef DIAGNOSTIC 133 static int ipprintfs = 0; 134 #endif 135 136 extern struct domain inetdomain; 137 extern struct ipprotosw inetsw[]; 138 u_char ip_protox[IPPROTO_MAX]; 139 static int ipqmaxlen = IFQ_MAXLEN; 140 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 141 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 142 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 143 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 144 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 145 146 struct ipstat ipstat; 147 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RD, 148 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 149 150 /* Packet reassembly stuff */ 151 #define IPREASS_NHASH_LOG2 6 152 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 153 #define IPREASS_HMASK (IPREASS_NHASH - 1) 154 #define IPREASS_HASH(x,y) \ 155 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 156 157 static struct ipq ipq[IPREASS_NHASH]; 158 static int nipq = 0; /* total # of reass queues */ 159 static int maxnipq; 160 const int ipintrq_present = 1; 161 162 #ifdef IPCTL_DEFMTU 163 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 164 &ip_mtu, 0, "Default MTU"); 165 #endif 166 167 #ifdef IPSTEALTH 168 static int ipstealth = 0; 169 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 170 &ipstealth, 0, ""); 171 #endif 172 173 174 /* Firewall hooks */ 175 ip_fw_chk_t *ip_fw_chk_ptr; 176 ip_fw_ctl_t *ip_fw_ctl_ptr; 177 int fw_enable = 1 ; 178 179 #ifdef DUMMYNET 180 ip_dn_ctl_t *ip_dn_ctl_ptr; 181 #endif 182 183 int (*fr_checkp) __P((struct ip *, int, struct ifnet *, int, struct mbuf **)) = NULL; 184 185 186 /* 187 * We need to save the IP options in case a protocol wants to respond 188 * to an incoming packet over the same route if the packet got here 189 * using IP source routing. This allows connection establishment and 190 * maintenance when the remote end is on a network that is not known 191 * to us. 192 */ 193 static int ip_nhops = 0; 194 static struct ip_srcrt { 195 struct in_addr dst; /* final destination */ 196 char nop; /* one NOP to align */ 197 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 198 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 199 } ip_srcrt; 200 201 struct sockaddr_in *ip_fw_fwd_addr; 202 203 static void save_rte __P((u_char *, struct in_addr)); 204 static int ip_dooptions __P((struct mbuf *)); 205 static void ip_forward __P((struct mbuf *, int)); 206 static void ip_freef __P((struct ipq *)); 207 #ifdef IPDIVERT 208 static struct mbuf *ip_reass __P((struct mbuf *, 209 struct ipq *, struct ipq *, u_int32_t *, u_int16_t *)); 210 #else 211 static struct mbuf *ip_reass __P((struct mbuf *, struct ipq *, struct ipq *)); 212 #endif 213 static struct in_ifaddr *ip_rtaddr __P((struct in_addr)); 214 static void ipintr __P((void)); 215 216 /* 217 * IP initialization: fill in IP protocol switch table. 218 * All protocols not implemented in kernel go to raw IP protocol handler. 219 */ 220 void 221 ip_init() 222 { 223 register struct ipprotosw *pr; 224 register int i; 225 226 TAILQ_INIT(&in_ifaddrhead); 227 pr = (struct ipprotosw *)pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 228 if (pr == 0) 229 panic("ip_init"); 230 for (i = 0; i < IPPROTO_MAX; i++) 231 ip_protox[i] = pr - inetsw; 232 for (pr = (struct ipprotosw *)inetdomain.dom_protosw; 233 pr < (struct ipprotosw *)inetdomain.dom_protoswNPROTOSW; pr++) 234 if (pr->pr_domain->dom_family == PF_INET && 235 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 236 ip_protox[pr->pr_protocol] = pr - inetsw; 237 238 for (i = 0; i < IPREASS_NHASH; i++) 239 ipq[i].next = ipq[i].prev = &ipq[i]; 240 241 maxnipq = nmbclusters/4; 242 243 ip_id = time_second & 0xffff; 244 ipintrq.ifq_maxlen = ipqmaxlen; 245 246 register_netisr(NETISR_IP, ipintr); 247 } 248 249 static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 250 static struct route ipforward_rt; 251 252 /* 253 * Ip input routine. Checksum and byte swap header. If fragmented 254 * try to reassemble. Process options. Pass to next level. 255 */ 256 void 257 ip_input(struct mbuf *m) 258 { 259 struct ip *ip; 260 struct ipq *fp; 261 struct in_ifaddr *ia; 262 int i, hlen, mff; 263 u_short sum; 264 u_int16_t divert_cookie; /* firewall cookie */ 265 #ifdef IPDIVERT 266 u_int32_t divert_info = 0; /* packet divert/tee info */ 267 #endif 268 struct ip_fw_chain *rule = NULL; 269 270 #ifdef IPDIVERT 271 /* Get and reset firewall cookie */ 272 divert_cookie = ip_divert_cookie; 273 ip_divert_cookie = 0; 274 #else 275 divert_cookie = 0; 276 #endif 277 278 #if defined(IPFIREWALL) && defined(DUMMYNET) 279 /* 280 * dummynet packet are prepended a vestigial mbuf with 281 * m_type = MT_DUMMYNET and m_data pointing to the matching 282 * rule. 283 */ 284 if (m->m_type == MT_DUMMYNET) { 285 rule = (struct ip_fw_chain *)(m->m_data) ; 286 m = m->m_next ; 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 (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 328 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 329 } else { 330 if (hlen == sizeof(struct ip)) { 331 sum = in_cksum_hdr(ip); 332 } else { 333 sum = in_cksum(m, hlen); 334 } 335 } 336 if (sum) { 337 ipstat.ips_badsum++; 338 goto bad; 339 } 340 341 /* 342 * Convert fields to host representation. 343 */ 344 NTOHS(ip->ip_len); 345 if (ip->ip_len < hlen) { 346 ipstat.ips_badlen++; 347 goto bad; 348 } 349 NTOHS(ip->ip_id); 350 NTOHS(ip->ip_off); 351 352 /* 353 * Check that the amount of data in the buffers 354 * is as at least much as the IP header would have us expect. 355 * Trim mbufs if longer than we expect. 356 * Drop packet if shorter than we expect. 357 */ 358 if (m->m_pkthdr.len < ip->ip_len) { 359 tooshort: 360 ipstat.ips_tooshort++; 361 goto bad; 362 } 363 if (m->m_pkthdr.len > ip->ip_len) { 364 if (m->m_len == m->m_pkthdr.len) { 365 m->m_len = ip->ip_len; 366 m->m_pkthdr.len = ip->ip_len; 367 } else 368 m_adj(m, ip->ip_len - m->m_pkthdr.len); 369 } 370 /* 371 * IpHack's section. 372 * Right now when no processing on packet has done 373 * and it is still fresh out of network we do our black 374 * deals with it. 375 * - Firewall: deny/allow/divert 376 * - Xlate: translate packet's addr/port (NAT). 377 * - Pipe: pass pkt through dummynet. 378 * - Wrap: fake packet's addr/port <unimpl.> 379 * - Encapsulate: put it in another IP and send out. <unimp.> 380 */ 381 382 #if defined(IPFIREWALL) && defined(DUMMYNET) 383 iphack: 384 #endif 385 /* 386 * Check if we want to allow this packet to be processed. 387 * Consider it to be bad if not. 388 */ 389 if (fr_checkp) { 390 struct mbuf *m1 = m; 391 392 if ((*fr_checkp)(ip, hlen, m->m_pkthdr.rcvif, 0, &m1) || !m1) 393 return; 394 ip = mtod(m = m1, struct ip *); 395 } 396 if (fw_enable && ip_fw_chk_ptr) { 397 #ifdef IPFIREWALL_FORWARD 398 /* 399 * If we've been forwarded from the output side, then 400 * skip the firewall a second time 401 */ 402 if (ip_fw_fwd_addr) 403 goto ours; 404 #endif /* IPFIREWALL_FORWARD */ 405 /* 406 * See the comment in ip_output for the return values 407 * produced by the firewall. 408 */ 409 i = (*ip_fw_chk_ptr)(&ip, 410 hlen, NULL, &divert_cookie, &m, &rule, &ip_fw_fwd_addr); 411 if (m == NULL) /* Packet discarded by firewall */ 412 return; 413 if (i == 0 && ip_fw_fwd_addr == NULL) /* common case */ 414 goto pass; 415 #ifdef DUMMYNET 416 if ((i & IP_FW_PORT_DYNT_FLAG) != 0) { 417 /* Send packet to the appropriate pipe */ 418 dummynet_io(i&0xffff,DN_TO_IP_IN,m,NULL,NULL,0, rule, 419 0); 420 return; 421 } 422 #endif 423 #ifdef IPDIVERT 424 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 425 /* Divert or tee packet */ 426 divert_info = i; 427 goto ours; 428 } 429 #endif 430 #ifdef IPFIREWALL_FORWARD 431 if (i == 0 && ip_fw_fwd_addr != NULL) 432 goto pass; 433 #endif 434 /* 435 * if we get here, the packet must be dropped 436 */ 437 m_freem(m); 438 return; 439 } 440 pass: 441 442 /* 443 * Process options and, if not destined for us, 444 * ship it on. ip_dooptions returns 1 when an 445 * error was detected (causing an icmp message 446 * to be sent and the original packet to be freed). 447 */ 448 ip_nhops = 0; /* for source routed packets */ 449 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 450 #ifdef IPFIREWALL_FORWARD 451 ip_fw_fwd_addr = NULL; 452 #endif 453 return; 454 } 455 456 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 457 * matter if it is destined to another node, or whether it is 458 * a multicast one, RSVP wants it! and prevents it from being forwarded 459 * anywhere else. Also checks if the rsvp daemon is running before 460 * grabbing the packet. 461 */ 462 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 463 goto ours; 464 465 /* 466 * Check our list of addresses, to see if the packet is for us. 467 * If we don't have any addresses, assume any unicast packet 468 * we receive might be for us (and let the upper layers deal 469 * with it). 470 */ 471 if (TAILQ_EMPTY(&in_ifaddrhead) && 472 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 473 goto ours; 474 475 for (ia = TAILQ_FIRST(&in_ifaddrhead); ia; 476 ia = TAILQ_NEXT(ia, ia_link)) { 477 #define satosin(sa) ((struct sockaddr_in *)(sa)) 478 479 #ifdef BOOTP_COMPAT 480 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 481 goto ours; 482 #endif 483 #ifdef IPFIREWALL_FORWARD 484 /* 485 * If the addr to forward to is one of ours, we pretend to 486 * be the destination for this packet. 487 */ 488 if (ip_fw_fwd_addr == NULL) { 489 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 490 goto ours; 491 } else if (IA_SIN(ia)->sin_addr.s_addr == 492 ip_fw_fwd_addr->sin_addr.s_addr) 493 goto ours; 494 #else 495 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 496 goto ours; 497 #endif 498 if (ia->ia_ifp && ia->ia_ifp->if_flags & IFF_BROADCAST) { 499 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 500 ip->ip_dst.s_addr) 501 goto ours; 502 if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr) 503 goto ours; 504 } 505 } 506 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 507 struct in_multi *inm; 508 if (ip_mrouter) { 509 /* 510 * If we are acting as a multicast router, all 511 * incoming multicast packets are passed to the 512 * kernel-level multicast forwarding function. 513 * The packet is returned (relatively) intact; if 514 * ip_mforward() returns a non-zero value, the packet 515 * must be discarded, else it may be accepted below. 516 * 517 * (The IP ident field is put in the same byte order 518 * as expected when ip_mforward() is called from 519 * ip_output().) 520 */ 521 ip->ip_id = htons(ip->ip_id); 522 if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 523 ipstat.ips_cantforward++; 524 m_freem(m); 525 return; 526 } 527 ip->ip_id = ntohs(ip->ip_id); 528 529 /* 530 * The process-level routing demon needs to receive 531 * all multicast IGMP packets, whether or not this 532 * host belongs to their destination groups. 533 */ 534 if (ip->ip_p == IPPROTO_IGMP) 535 goto ours; 536 ipstat.ips_forward++; 537 } 538 /* 539 * See if we belong to the destination multicast group on the 540 * arrival interface. 541 */ 542 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 543 if (inm == NULL) { 544 ipstat.ips_notmember++; 545 m_freem(m); 546 return; 547 } 548 goto ours; 549 } 550 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 551 goto ours; 552 if (ip->ip_dst.s_addr == INADDR_ANY) 553 goto ours; 554 555 #if defined(NFAITH) && 0 < NFAITH 556 /* 557 * FAITH(Firewall Aided Internet Translator) 558 */ 559 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { 560 if (ip_keepfaith) { 561 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 562 goto ours; 563 } 564 m_freem(m); 565 return; 566 } 567 #endif 568 /* 569 * Not for us; forward if possible and desirable. 570 */ 571 if (ipforwarding == 0) { 572 ipstat.ips_cantforward++; 573 m_freem(m); 574 } else 575 ip_forward(m, 0); 576 #ifdef IPFIREWALL_FORWARD 577 ip_fw_fwd_addr = NULL; 578 #endif 579 return; 580 581 ours: 582 583 /* 584 * If offset or IP_MF are set, must reassemble. 585 * Otherwise, nothing need be done. 586 * (We could look in the reassembly queue to see 587 * if the packet was previously fragmented, 588 * but it's not worth the time; just let them time out.) 589 */ 590 if (ip->ip_off & (IP_MF | IP_OFFMASK | IP_RF)) { 591 592 #if 0 /* 593 * Reassembly should be able to treat a mbuf cluster, for later 594 * operation of contiguous protocol headers on the cluster. (KAME) 595 */ 596 if (m->m_flags & M_EXT) { /* XXX */ 597 if ((m = m_pullup(m, hlen)) == 0) { 598 ipstat.ips_toosmall++; 599 #ifdef IPFIREWALL_FORWARD 600 ip_fw_fwd_addr = NULL; 601 #endif 602 return; 603 } 604 ip = mtod(m, struct ip *); 605 } 606 #endif 607 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 608 /* 609 * Look for queue of fragments 610 * of this datagram. 611 */ 612 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 613 if (ip->ip_id == fp->ipq_id && 614 ip->ip_src.s_addr == fp->ipq_src.s_addr && 615 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 616 ip->ip_p == fp->ipq_p) 617 goto found; 618 619 fp = 0; 620 621 /* check if there's a place for the new queue */ 622 if (nipq > maxnipq) { 623 /* 624 * drop something from the tail of the current queue 625 * before proceeding further 626 */ 627 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 628 for (i = 0; i < IPREASS_NHASH; i++) { 629 if (ipq[i].prev != &ipq[i]) { 630 ip_freef(ipq[i].prev); 631 break; 632 } 633 } 634 } else 635 ip_freef(ipq[sum].prev); 636 } 637 found: 638 /* 639 * Adjust ip_len to not reflect header, 640 * set ip_mff if more fragments are expected, 641 * convert offset of this to bytes. 642 */ 643 ip->ip_len -= hlen; 644 mff = (ip->ip_off & IP_MF) != 0; 645 if (mff) { 646 /* 647 * Make sure that fragments have a data length 648 * that's a non-zero multiple of 8 bytes. 649 */ 650 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 651 ipstat.ips_toosmall++; /* XXX */ 652 goto bad; 653 } 654 m->m_flags |= M_FRAG; 655 } 656 ip->ip_off <<= 3; 657 658 /* 659 * If datagram marked as having more fragments 660 * or if this is not the first fragment, 661 * attempt reassembly; if it succeeds, proceed. 662 */ 663 if (mff || ip->ip_off) { 664 ipstat.ips_fragments++; 665 m->m_pkthdr.header = ip; 666 #ifdef IPDIVERT 667 m = ip_reass(m, 668 fp, &ipq[sum], &divert_info, &divert_cookie); 669 #else 670 m = ip_reass(m, fp, &ipq[sum]); 671 #endif 672 if (m == 0) { 673 #ifdef IPFIREWALL_FORWARD 674 ip_fw_fwd_addr = NULL; 675 #endif 676 return; 677 } 678 /* Get the length of the reassembled packets header */ 679 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 680 ipstat.ips_reassembled++; 681 ip = mtod(m, struct ip *); 682 #ifdef IPDIVERT 683 /* Restore original checksum before diverting packet */ 684 if (divert_info != 0) { 685 ip->ip_len += hlen; 686 HTONS(ip->ip_len); 687 HTONS(ip->ip_off); 688 HTONS(ip->ip_id); 689 ip->ip_sum = 0; 690 ip->ip_sum = in_cksum_hdr(ip); 691 NTOHS(ip->ip_id); 692 NTOHS(ip->ip_off); 693 NTOHS(ip->ip_len); 694 ip->ip_len -= hlen; 695 } 696 #endif 697 } else 698 if (fp) 699 ip_freef(fp); 700 } else 701 ip->ip_len -= hlen; 702 703 #ifdef IPDIVERT 704 /* 705 * Divert or tee packet to the divert protocol if required. 706 * 707 * If divert_info is zero then cookie should be too, so we shouldn't 708 * need to clear them here. Assume divert_packet() does so also. 709 */ 710 if (divert_info != 0) { 711 struct mbuf *clone = NULL; 712 713 /* Clone packet if we're doing a 'tee' */ 714 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 715 clone = m_dup(m, M_DONTWAIT); 716 717 /* Restore packet header fields to original values */ 718 ip->ip_len += hlen; 719 HTONS(ip->ip_len); 720 HTONS(ip->ip_off); 721 HTONS(ip->ip_id); 722 723 /* Deliver packet to divert input routine */ 724 ip_divert_cookie = divert_cookie; 725 divert_packet(m, 1, divert_info & 0xffff); 726 ipstat.ips_delivered++; 727 728 /* If 'tee', continue with original packet */ 729 if (clone == NULL) 730 return; 731 m = clone; 732 ip = mtod(m, struct ip *); 733 } 734 #endif 735 736 /* 737 * Switch out to protocol's input routine. 738 */ 739 ipstat.ips_delivered++; 740 { 741 int off = hlen, nh = ip->ip_p; 742 743 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, off, nh); 744 #ifdef IPFIREWALL_FORWARD 745 ip_fw_fwd_addr = NULL; /* tcp needed it */ 746 #endif 747 return; 748 } 749 bad: 750 #ifdef IPFIREWALL_FORWARD 751 ip_fw_fwd_addr = NULL; 752 #endif 753 m_freem(m); 754 } 755 756 /* 757 * IP software interrupt routine - to go away sometime soon 758 */ 759 static void 760 ipintr(void) 761 { 762 int s; 763 struct mbuf *m; 764 765 while(1) { 766 s = splimp(); 767 IF_DEQUEUE(&ipintrq, m); 768 splx(s); 769 if (m == 0) 770 return; 771 ip_input(m); 772 } 773 } 774 775 /* 776 * Take incoming datagram fragment and try to reassemble it into 777 * whole datagram. If a chain for reassembly of this datagram already 778 * exists, then it is given as fp; otherwise have to make a chain. 779 * 780 * When IPDIVERT enabled, keep additional state with each packet that 781 * tells us if we need to divert or tee the packet we're building. 782 */ 783 784 static struct mbuf * 785 #ifdef IPDIVERT 786 ip_reass(m, fp, where, divinfo, divcookie) 787 #else 788 ip_reass(m, fp, where) 789 #endif 790 register struct mbuf *m; 791 register struct ipq *fp; 792 struct ipq *where; 793 #ifdef IPDIVERT 794 u_int32_t *divinfo; 795 u_int16_t *divcookie; 796 #endif 797 { 798 struct ip *ip = mtod(m, struct ip *); 799 register struct mbuf *p = 0, *q, *nq; 800 struct mbuf *t; 801 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 802 int i, next; 803 804 /* 805 * Presence of header sizes in mbufs 806 * would confuse code below. 807 */ 808 m->m_data += hlen; 809 m->m_len -= hlen; 810 811 /* 812 * If first fragment to arrive, create a reassembly queue. 813 */ 814 if (fp == 0) { 815 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 816 goto dropfrag; 817 fp = mtod(t, struct ipq *); 818 insque(fp, where); 819 nipq++; 820 fp->ipq_ttl = IPFRAGTTL; 821 fp->ipq_p = ip->ip_p; 822 fp->ipq_id = ip->ip_id; 823 fp->ipq_src = ip->ip_src; 824 fp->ipq_dst = ip->ip_dst; 825 fp->ipq_frags = m; 826 m->m_nextpkt = NULL; 827 #ifdef IPDIVERT 828 fp->ipq_div_info = 0; 829 fp->ipq_div_cookie = 0; 830 #endif 831 goto inserted; 832 } 833 834 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 835 836 /* 837 * Find a segment which begins after this one does. 838 */ 839 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 840 if (GETIP(q)->ip_off > ip->ip_off) 841 break; 842 843 /* 844 * If there is a preceding segment, it may provide some of 845 * our data already. If so, drop the data from the incoming 846 * segment. If it provides all of our data, drop us, otherwise 847 * stick new segment in the proper place. 848 * 849 * If some of the data is dropped from the the preceding 850 * segment, then it's checksum is invalidated. 851 */ 852 if (p) { 853 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 854 if (i > 0) { 855 if (i >= ip->ip_len) 856 goto dropfrag; 857 m_adj(m, i); 858 m->m_pkthdr.csum_flags = 0; 859 ip->ip_off += i; 860 ip->ip_len -= i; 861 } 862 m->m_nextpkt = p->m_nextpkt; 863 p->m_nextpkt = m; 864 } else { 865 m->m_nextpkt = fp->ipq_frags; 866 fp->ipq_frags = m; 867 } 868 869 /* 870 * While we overlap succeeding segments trim them or, 871 * if they are completely covered, dequeue them. 872 */ 873 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 874 q = nq) { 875 i = (ip->ip_off + ip->ip_len) - 876 GETIP(q)->ip_off; 877 if (i < GETIP(q)->ip_len) { 878 GETIP(q)->ip_len -= i; 879 GETIP(q)->ip_off += i; 880 m_adj(q, i); 881 q->m_pkthdr.csum_flags = 0; 882 break; 883 } 884 nq = q->m_nextpkt; 885 m->m_nextpkt = nq; 886 m_freem(q); 887 } 888 889 inserted: 890 891 #ifdef IPDIVERT 892 /* 893 * Transfer firewall instructions to the fragment structure. 894 * Any fragment diverting causes the whole packet to divert. 895 */ 896 fp->ipq_div_info = *divinfo; 897 fp->ipq_div_cookie = *divcookie; 898 *divinfo = 0; 899 *divcookie = 0; 900 #endif 901 902 /* 903 * Check for complete reassembly. 904 */ 905 next = 0; 906 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 907 if (GETIP(q)->ip_off != next) 908 return (0); 909 next += GETIP(q)->ip_len; 910 } 911 /* Make sure the last packet didn't have the IP_MF flag */ 912 if (p->m_flags & M_FRAG) 913 return (0); 914 915 /* 916 * Reassembly is complete. Make sure the packet is a sane size. 917 */ 918 q = fp->ipq_frags; 919 ip = GETIP(q); 920 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 921 ipstat.ips_toolong++; 922 ip_freef(fp); 923 return (0); 924 } 925 926 /* 927 * Concatenate fragments. 928 */ 929 m = q; 930 t = m->m_next; 931 m->m_next = 0; 932 m_cat(m, t); 933 nq = q->m_nextpkt; 934 q->m_nextpkt = 0; 935 for (q = nq; q != NULL; q = nq) { 936 nq = q->m_nextpkt; 937 q->m_nextpkt = NULL; 938 m_cat(m, q); 939 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 940 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 941 } 942 943 #ifdef IPDIVERT 944 /* 945 * Extract firewall instructions from the fragment structure. 946 */ 947 *divinfo = fp->ipq_div_info; 948 *divcookie = fp->ipq_div_cookie; 949 #endif 950 951 /* 952 * Create header for new ip packet by 953 * modifying header of first packet; 954 * dequeue and discard fragment reassembly header. 955 * Make header visible. 956 */ 957 ip->ip_len = next; 958 ip->ip_src = fp->ipq_src; 959 ip->ip_dst = fp->ipq_dst; 960 remque(fp); 961 nipq--; 962 (void) m_free(dtom(fp)); 963 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 964 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 965 /* some debugging cruft by sklower, below, will go away soon */ 966 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 967 register int plen = 0; 968 for (t = m; t; t = t->m_next) 969 plen += t->m_len; 970 m->m_pkthdr.len = plen; 971 } 972 return (m); 973 974 dropfrag: 975 #ifdef IPDIVERT 976 *divinfo = 0; 977 *divcookie = 0; 978 #endif 979 ipstat.ips_fragdropped++; 980 m_freem(m); 981 return (0); 982 983 #undef GETIP 984 } 985 986 /* 987 * Free a fragment reassembly header and all 988 * associated datagrams. 989 */ 990 static void 991 ip_freef(fp) 992 struct ipq *fp; 993 { 994 register struct mbuf *q; 995 996 while (fp->ipq_frags) { 997 q = fp->ipq_frags; 998 fp->ipq_frags = q->m_nextpkt; 999 m_freem(q); 1000 } 1001 remque(fp); 1002 (void) m_free(dtom(fp)); 1003 nipq--; 1004 } 1005 1006 /* 1007 * IP timer processing; 1008 * if a timer expires on a reassembly 1009 * queue, discard it. 1010 */ 1011 void 1012 ip_slowtimo() 1013 { 1014 register struct ipq *fp; 1015 int s = splnet(); 1016 int i; 1017 1018 for (i = 0; i < IPREASS_NHASH; i++) { 1019 fp = ipq[i].next; 1020 if (fp == 0) 1021 continue; 1022 while (fp != &ipq[i]) { 1023 --fp->ipq_ttl; 1024 fp = fp->next; 1025 if (fp->prev->ipq_ttl == 0) { 1026 ipstat.ips_fragtimeout++; 1027 ip_freef(fp->prev); 1028 } 1029 } 1030 } 1031 ipflow_slowtimo(); 1032 splx(s); 1033 } 1034 1035 /* 1036 * Drain off all datagram fragments. 1037 */ 1038 void 1039 ip_drain() 1040 { 1041 int i; 1042 1043 for (i = 0; i < IPREASS_NHASH; i++) { 1044 while (ipq[i].next != &ipq[i]) { 1045 ipstat.ips_fragdropped++; 1046 ip_freef(ipq[i].next); 1047 } 1048 } 1049 in_rtqdrain(); 1050 } 1051 1052 /* 1053 * Do option processing on a datagram, 1054 * possibly discarding it if bad options are encountered, 1055 * or forwarding it if source-routed. 1056 * Returns 1 if packet has been forwarded/freed, 1057 * 0 if the packet should be processed further. 1058 */ 1059 static int 1060 ip_dooptions(m) 1061 struct mbuf *m; 1062 { 1063 register struct ip *ip = mtod(m, struct ip *); 1064 register u_char *cp; 1065 register struct ip_timestamp *ipt; 1066 register struct in_ifaddr *ia; 1067 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1068 struct in_addr *sin, dst; 1069 n_time ntime; 1070 1071 dst = ip->ip_dst; 1072 cp = (u_char *)(ip + 1); 1073 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1074 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1075 opt = cp[IPOPT_OPTVAL]; 1076 if (opt == IPOPT_EOL) 1077 break; 1078 if (opt == IPOPT_NOP) 1079 optlen = 1; 1080 else { 1081 optlen = cp[IPOPT_OLEN]; 1082 if (optlen <= 0 || optlen > cnt) { 1083 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1084 goto bad; 1085 } 1086 } 1087 switch (opt) { 1088 1089 default: 1090 break; 1091 1092 /* 1093 * Source routing with record. 1094 * Find interface with current destination address. 1095 * If none on this machine then drop if strictly routed, 1096 * or do nothing if loosely routed. 1097 * Record interface address and bring up next address 1098 * component. If strictly routed make sure next 1099 * address is on directly accessible net. 1100 */ 1101 case IPOPT_LSRR: 1102 case IPOPT_SSRR: 1103 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1104 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1105 goto bad; 1106 } 1107 ipaddr.sin_addr = ip->ip_dst; 1108 ia = (struct in_ifaddr *) 1109 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1110 if (ia == 0) { 1111 if (opt == IPOPT_SSRR) { 1112 type = ICMP_UNREACH; 1113 code = ICMP_UNREACH_SRCFAIL; 1114 goto bad; 1115 } 1116 if (!ip_dosourceroute) 1117 goto nosourcerouting; 1118 /* 1119 * Loose routing, and not at next destination 1120 * yet; nothing to do except forward. 1121 */ 1122 break; 1123 } 1124 off--; /* 0 origin */ 1125 if (off > optlen - sizeof(struct in_addr)) { 1126 /* 1127 * End of source route. Should be for us. 1128 */ 1129 if (!ip_acceptsourceroute) 1130 goto nosourcerouting; 1131 save_rte(cp, ip->ip_src); 1132 break; 1133 } 1134 1135 if (!ip_dosourceroute) { 1136 if (ipforwarding) { 1137 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1138 /* 1139 * Acting as a router, so generate ICMP 1140 */ 1141 nosourcerouting: 1142 strcpy(buf, inet_ntoa(ip->ip_dst)); 1143 log(LOG_WARNING, 1144 "attempted source route from %s to %s\n", 1145 inet_ntoa(ip->ip_src), buf); 1146 type = ICMP_UNREACH; 1147 code = ICMP_UNREACH_SRCFAIL; 1148 goto bad; 1149 } else { 1150 /* 1151 * Not acting as a router, so silently drop. 1152 */ 1153 ipstat.ips_cantforward++; 1154 m_freem(m); 1155 return (1); 1156 } 1157 } 1158 1159 /* 1160 * locate outgoing interface 1161 */ 1162 (void)memcpy(&ipaddr.sin_addr, cp + off, 1163 sizeof(ipaddr.sin_addr)); 1164 1165 if (opt == IPOPT_SSRR) { 1166 #define INA struct in_ifaddr * 1167 #define SA struct sockaddr * 1168 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1169 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1170 } else 1171 ia = ip_rtaddr(ipaddr.sin_addr); 1172 if (ia == 0) { 1173 type = ICMP_UNREACH; 1174 code = ICMP_UNREACH_SRCFAIL; 1175 goto bad; 1176 } 1177 ip->ip_dst = ipaddr.sin_addr; 1178 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1179 sizeof(struct in_addr)); 1180 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1181 /* 1182 * Let ip_intr's mcast routing check handle mcast pkts 1183 */ 1184 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1185 break; 1186 1187 case IPOPT_RR: 1188 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1189 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1190 goto bad; 1191 } 1192 /* 1193 * If no space remains, ignore. 1194 */ 1195 off--; /* 0 origin */ 1196 if (off > optlen - sizeof(struct in_addr)) 1197 break; 1198 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1199 sizeof(ipaddr.sin_addr)); 1200 /* 1201 * locate outgoing interface; if we're the destination, 1202 * use the incoming interface (should be same). 1203 */ 1204 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1205 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1206 type = ICMP_UNREACH; 1207 code = ICMP_UNREACH_HOST; 1208 goto bad; 1209 } 1210 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1211 sizeof(struct in_addr)); 1212 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1213 break; 1214 1215 case IPOPT_TS: 1216 code = cp - (u_char *)ip; 1217 ipt = (struct ip_timestamp *)cp; 1218 if (ipt->ipt_len < 5) 1219 goto bad; 1220 if (ipt->ipt_ptr > ipt->ipt_len - sizeof(int32_t)) { 1221 if (++ipt->ipt_oflw == 0) 1222 goto bad; 1223 break; 1224 } 1225 sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); 1226 switch (ipt->ipt_flg) { 1227 1228 case IPOPT_TS_TSONLY: 1229 break; 1230 1231 case IPOPT_TS_TSANDADDR: 1232 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1233 sizeof(struct in_addr) > ipt->ipt_len) 1234 goto bad; 1235 ipaddr.sin_addr = dst; 1236 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1237 m->m_pkthdr.rcvif); 1238 if (ia == 0) 1239 continue; 1240 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1241 sizeof(struct in_addr)); 1242 ipt->ipt_ptr += sizeof(struct in_addr); 1243 break; 1244 1245 case IPOPT_TS_PRESPEC: 1246 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1247 sizeof(struct in_addr) > ipt->ipt_len) 1248 goto bad; 1249 (void)memcpy(&ipaddr.sin_addr, sin, 1250 sizeof(struct in_addr)); 1251 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1252 continue; 1253 ipt->ipt_ptr += sizeof(struct in_addr); 1254 break; 1255 1256 default: 1257 goto bad; 1258 } 1259 ntime = iptime(); 1260 (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime, 1261 sizeof(n_time)); 1262 ipt->ipt_ptr += sizeof(n_time); 1263 } 1264 } 1265 if (forward && ipforwarding) { 1266 ip_forward(m, 1); 1267 return (1); 1268 } 1269 return (0); 1270 bad: 1271 ip->ip_len -= IP_VHL_HL(ip->ip_vhl) << 2; /* XXX icmp_error adds in hdr length */ 1272 icmp_error(m, type, code, 0, 0); 1273 ipstat.ips_badoptions++; 1274 return (1); 1275 } 1276 1277 /* 1278 * Given address of next destination (final or next hop), 1279 * return internet address info of interface to be used to get there. 1280 */ 1281 static struct in_ifaddr * 1282 ip_rtaddr(dst) 1283 struct in_addr dst; 1284 { 1285 register struct sockaddr_in *sin; 1286 1287 sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; 1288 1289 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 1290 if (ipforward_rt.ro_rt) { 1291 RTFREE(ipforward_rt.ro_rt); 1292 ipforward_rt.ro_rt = 0; 1293 } 1294 sin->sin_family = AF_INET; 1295 sin->sin_len = sizeof(*sin); 1296 sin->sin_addr = dst; 1297 1298 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1299 } 1300 if (ipforward_rt.ro_rt == 0) 1301 return ((struct in_ifaddr *)0); 1302 return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); 1303 } 1304 1305 /* 1306 * Save incoming source route for use in replies, 1307 * to be picked up later by ip_srcroute if the receiver is interested. 1308 */ 1309 void 1310 save_rte(option, dst) 1311 u_char *option; 1312 struct in_addr dst; 1313 { 1314 unsigned olen; 1315 1316 olen = option[IPOPT_OLEN]; 1317 #ifdef DIAGNOSTIC 1318 if (ipprintfs) 1319 printf("save_rte: olen %d\n", olen); 1320 #endif 1321 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1322 return; 1323 bcopy(option, ip_srcrt.srcopt, olen); 1324 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1325 ip_srcrt.dst = dst; 1326 } 1327 1328 /* 1329 * Retrieve incoming source route for use in replies, 1330 * in the same form used by setsockopt. 1331 * The first hop is placed before the options, will be removed later. 1332 */ 1333 struct mbuf * 1334 ip_srcroute() 1335 { 1336 register struct in_addr *p, *q; 1337 register struct mbuf *m; 1338 1339 if (ip_nhops == 0) 1340 return ((struct mbuf *)0); 1341 m = m_get(M_DONTWAIT, MT_HEADER); 1342 if (m == 0) 1343 return ((struct mbuf *)0); 1344 1345 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1346 1347 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1348 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1349 OPTSIZ; 1350 #ifdef DIAGNOSTIC 1351 if (ipprintfs) 1352 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1353 #endif 1354 1355 /* 1356 * First save first hop for return route 1357 */ 1358 p = &ip_srcrt.route[ip_nhops - 1]; 1359 *(mtod(m, struct in_addr *)) = *p--; 1360 #ifdef DIAGNOSTIC 1361 if (ipprintfs) 1362 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1363 #endif 1364 1365 /* 1366 * Copy option fields and padding (nop) to mbuf. 1367 */ 1368 ip_srcrt.nop = IPOPT_NOP; 1369 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1370 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1371 &ip_srcrt.nop, OPTSIZ); 1372 q = (struct in_addr *)(mtod(m, caddr_t) + 1373 sizeof(struct in_addr) + OPTSIZ); 1374 #undef OPTSIZ 1375 /* 1376 * Record return path as an IP source route, 1377 * reversing the path (pointers are now aligned). 1378 */ 1379 while (p >= ip_srcrt.route) { 1380 #ifdef DIAGNOSTIC 1381 if (ipprintfs) 1382 printf(" %lx", (u_long)ntohl(q->s_addr)); 1383 #endif 1384 *q++ = *p--; 1385 } 1386 /* 1387 * Last hop goes to final destination. 1388 */ 1389 *q = ip_srcrt.dst; 1390 #ifdef DIAGNOSTIC 1391 if (ipprintfs) 1392 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1393 #endif 1394 return (m); 1395 } 1396 1397 /* 1398 * Strip out IP options, at higher 1399 * level protocol in the kernel. 1400 * Second argument is buffer to which options 1401 * will be moved, and return value is their length. 1402 * XXX should be deleted; last arg currently ignored. 1403 */ 1404 void 1405 ip_stripoptions(m, mopt) 1406 register struct mbuf *m; 1407 struct mbuf *mopt; 1408 { 1409 register int i; 1410 struct ip *ip = mtod(m, struct ip *); 1411 register caddr_t opts; 1412 int olen; 1413 1414 olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1415 opts = (caddr_t)(ip + 1); 1416 i = m->m_len - (sizeof (struct ip) + olen); 1417 bcopy(opts + olen, opts, (unsigned)i); 1418 m->m_len -= olen; 1419 if (m->m_flags & M_PKTHDR) 1420 m->m_pkthdr.len -= olen; 1421 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1422 } 1423 1424 u_char inetctlerrmap[PRC_NCMDS] = { 1425 0, 0, 0, 0, 1426 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1427 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1428 EMSGSIZE, EHOSTUNREACH, 0, 0, 1429 0, 0, 0, 0, 1430 ENOPROTOOPT 1431 }; 1432 1433 /* 1434 * Forward a packet. If some error occurs return the sender 1435 * an icmp packet. Note we can't always generate a meaningful 1436 * icmp message because icmp doesn't have a large enough repertoire 1437 * of codes and types. 1438 * 1439 * If not forwarding, just drop the packet. This could be confusing 1440 * if ipforwarding was zero but some routing protocol was advancing 1441 * us as a gateway to somewhere. However, we must let the routing 1442 * protocol deal with that. 1443 * 1444 * The srcrt parameter indicates whether the packet is being forwarded 1445 * via a source route. 1446 */ 1447 static void 1448 ip_forward(m, srcrt) 1449 struct mbuf *m; 1450 int srcrt; 1451 { 1452 register struct ip *ip = mtod(m, struct ip *); 1453 register struct sockaddr_in *sin; 1454 register struct rtentry *rt; 1455 int error, type = 0, code = 0; 1456 struct mbuf *mcopy; 1457 n_long dest; 1458 struct ifnet *destifp; 1459 #ifdef IPSEC 1460 struct ifnet dummyifp; 1461 #endif 1462 1463 dest = 0; 1464 #ifdef DIAGNOSTIC 1465 if (ipprintfs) 1466 printf("forward: src %lx dst %lx ttl %x\n", 1467 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1468 ip->ip_ttl); 1469 #endif 1470 1471 1472 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1473 ipstat.ips_cantforward++; 1474 m_freem(m); 1475 return; 1476 } 1477 HTONS(ip->ip_id); 1478 #ifdef IPSTEALTH 1479 if (!ipstealth) { 1480 #endif 1481 if (ip->ip_ttl <= IPTTLDEC) { 1482 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1483 dest, 0); 1484 return; 1485 } 1486 ip->ip_ttl -= IPTTLDEC; 1487 #ifdef IPSTEALTH 1488 } 1489 #endif 1490 1491 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1492 if ((rt = ipforward_rt.ro_rt) == 0 || 1493 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1494 if (ipforward_rt.ro_rt) { 1495 RTFREE(ipforward_rt.ro_rt); 1496 ipforward_rt.ro_rt = 0; 1497 } 1498 sin->sin_family = AF_INET; 1499 sin->sin_len = sizeof(*sin); 1500 sin->sin_addr = ip->ip_dst; 1501 1502 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1503 if (ipforward_rt.ro_rt == 0) { 1504 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1505 return; 1506 } 1507 rt = ipforward_rt.ro_rt; 1508 } 1509 1510 /* 1511 * Save at most 64 bytes of the packet in case 1512 * we need to generate an ICMP message to the src. 1513 */ 1514 mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); 1515 1516 /* 1517 * If forwarding packet using same interface that it came in on, 1518 * perhaps should send a redirect to sender to shortcut a hop. 1519 * Only send redirect if source is sending directly to us, 1520 * and if packet was not source routed (or has any options). 1521 * Also, don't send redirect if forwarding using a default route 1522 * or a route modified by a redirect. 1523 */ 1524 #define satosin(sa) ((struct sockaddr_in *)(sa)) 1525 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1526 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1527 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1528 ipsendredirects && !srcrt) { 1529 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1530 u_long src = ntohl(ip->ip_src.s_addr); 1531 1532 if (RTA(rt) && 1533 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1534 if (rt->rt_flags & RTF_GATEWAY) 1535 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1536 else 1537 dest = ip->ip_dst.s_addr; 1538 /* Router requirements says to only send host redirects */ 1539 type = ICMP_REDIRECT; 1540 code = ICMP_REDIRECT_HOST; 1541 #ifdef DIAGNOSTIC 1542 if (ipprintfs) 1543 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1544 #endif 1545 } 1546 } 1547 1548 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1549 IP_FORWARDING, 0); 1550 if (error) 1551 ipstat.ips_cantforward++; 1552 else { 1553 ipstat.ips_forward++; 1554 if (type) 1555 ipstat.ips_redirectsent++; 1556 else { 1557 if (mcopy) { 1558 ipflow_create(&ipforward_rt, mcopy); 1559 m_freem(mcopy); 1560 } 1561 return; 1562 } 1563 } 1564 if (mcopy == NULL) 1565 return; 1566 destifp = NULL; 1567 1568 switch (error) { 1569 1570 case 0: /* forwarded, but need redirect */ 1571 /* type, code set above */ 1572 break; 1573 1574 case ENETUNREACH: /* shouldn't happen, checked above */ 1575 case EHOSTUNREACH: 1576 case ENETDOWN: 1577 case EHOSTDOWN: 1578 default: 1579 type = ICMP_UNREACH; 1580 code = ICMP_UNREACH_HOST; 1581 break; 1582 1583 case EMSGSIZE: 1584 type = ICMP_UNREACH; 1585 code = ICMP_UNREACH_NEEDFRAG; 1586 #ifndef IPSEC 1587 if (ipforward_rt.ro_rt) 1588 destifp = ipforward_rt.ro_rt->rt_ifp; 1589 #else 1590 /* 1591 * If the packet is routed over IPsec tunnel, tell the 1592 * originator the tunnel MTU. 1593 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz 1594 * XXX quickhack!!! 1595 */ 1596 if (ipforward_rt.ro_rt) { 1597 struct secpolicy *sp = NULL; 1598 int ipsecerror; 1599 int ipsechdr; 1600 struct route *ro; 1601 1602 sp = ipsec4_getpolicybyaddr(mcopy, 1603 IPSEC_DIR_OUTBOUND, 1604 IP_FORWARDING, 1605 &ipsecerror); 1606 1607 if (sp == NULL) 1608 destifp = ipforward_rt.ro_rt->rt_ifp; 1609 else { 1610 /* count IPsec header size */ 1611 ipsechdr = ipsec4_hdrsiz(mcopy, 1612 IPSEC_DIR_OUTBOUND, 1613 NULL); 1614 1615 /* 1616 * find the correct route for outer IPv4 1617 * header, compute tunnel MTU. 1618 * 1619 * XXX BUG ALERT 1620 * The "dummyifp" code relies upon the fact 1621 * that icmp_error() touches only ifp->if_mtu. 1622 */ 1623 /*XXX*/ 1624 destifp = NULL; 1625 if (sp->req != NULL 1626 && sp->req->sav != NULL 1627 && sp->req->sav->sah != NULL) { 1628 ro = &sp->req->sav->sah->sa_route; 1629 if (ro->ro_rt && ro->ro_rt->rt_ifp) { 1630 dummyifp.if_mtu = 1631 ro->ro_rt->rt_ifp->if_mtu; 1632 dummyifp.if_mtu -= ipsechdr; 1633 destifp = &dummyifp; 1634 } 1635 } 1636 1637 key_freesp(sp); 1638 } 1639 } 1640 #endif /*IPSEC*/ 1641 ipstat.ips_cantfrag++; 1642 break; 1643 1644 case ENOBUFS: 1645 type = ICMP_SOURCEQUENCH; 1646 code = 0; 1647 break; 1648 } 1649 icmp_error(mcopy, type, code, dest, destifp); 1650 } 1651 1652 void 1653 ip_savecontrol(inp, mp, ip, m) 1654 register struct inpcb *inp; 1655 register struct mbuf **mp; 1656 register struct ip *ip; 1657 register struct mbuf *m; 1658 { 1659 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1660 struct timeval tv; 1661 1662 microtime(&tv); 1663 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1664 SCM_TIMESTAMP, SOL_SOCKET); 1665 if (*mp) 1666 mp = &(*mp)->m_next; 1667 } 1668 if (inp->inp_flags & INP_RECVDSTADDR) { 1669 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1670 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1671 if (*mp) 1672 mp = &(*mp)->m_next; 1673 } 1674 #ifdef notyet 1675 /* XXX 1676 * Moving these out of udp_input() made them even more broken 1677 * than they already were. 1678 */ 1679 /* options were tossed already */ 1680 if (inp->inp_flags & INP_RECVOPTS) { 1681 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1682 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1683 if (*mp) 1684 mp = &(*mp)->m_next; 1685 } 1686 /* ip_srcroute doesn't do what we want here, need to fix */ 1687 if (inp->inp_flags & INP_RECVRETOPTS) { 1688 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1689 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1690 if (*mp) 1691 mp = &(*mp)->m_next; 1692 } 1693 #endif 1694 if (inp->inp_flags & INP_RECVIF) { 1695 struct ifnet *ifp; 1696 struct sdlbuf { 1697 struct sockaddr_dl sdl; 1698 u_char pad[32]; 1699 } sdlbuf; 1700 struct sockaddr_dl *sdp; 1701 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1702 1703 if (((ifp = m->m_pkthdr.rcvif)) 1704 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1705 sdp = (struct sockaddr_dl *)(ifnet_addrs 1706 [ifp->if_index - 1]->ifa_addr); 1707 /* 1708 * Change our mind and don't try copy. 1709 */ 1710 if ((sdp->sdl_family != AF_LINK) 1711 || (sdp->sdl_len > sizeof(sdlbuf))) { 1712 goto makedummy; 1713 } 1714 bcopy(sdp, sdl2, sdp->sdl_len); 1715 } else { 1716 makedummy: 1717 sdl2->sdl_len 1718 = offsetof(struct sockaddr_dl, sdl_data[0]); 1719 sdl2->sdl_family = AF_LINK; 1720 sdl2->sdl_index = 0; 1721 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1722 } 1723 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1724 IP_RECVIF, IPPROTO_IP); 1725 if (*mp) 1726 mp = &(*mp)->m_next; 1727 } 1728 } 1729 1730 int 1731 ip_rsvp_init(struct socket *so) 1732 { 1733 if (so->so_type != SOCK_RAW || 1734 so->so_proto->pr_protocol != IPPROTO_RSVP) 1735 return EOPNOTSUPP; 1736 1737 if (ip_rsvpd != NULL) 1738 return EADDRINUSE; 1739 1740 ip_rsvpd = so; 1741 /* 1742 * This may seem silly, but we need to be sure we don't over-increment 1743 * the RSVP counter, in case something slips up. 1744 */ 1745 if (!ip_rsvp_on) { 1746 ip_rsvp_on = 1; 1747 rsvp_on++; 1748 } 1749 1750 return 0; 1751 } 1752 1753 int 1754 ip_rsvp_done(void) 1755 { 1756 ip_rsvpd = NULL; 1757 /* 1758 * This may seem silly, but we need to be sure we don't over-decrement 1759 * the RSVP counter, in case something slips up. 1760 */ 1761 if (ip_rsvp_on) { 1762 ip_rsvp_on = 0; 1763 rsvp_on--; 1764 } 1765 return 0; 1766 } 1767