1 /* $OpenBSD: ip_input.c,v 1.281 2016/09/15 02:00:18 dlg Exp $ */ 2 /* $NetBSD: ip_input.c,v 1.30 1996/03/16 23:53:58 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1988, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 33 */ 34 35 #include "pf.h" 36 #include "carp.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/mbuf.h> 41 #include <sys/domain.h> 42 #include <sys/protosw.h> 43 #include <sys/socket.h> 44 #include <sys/socketvar.h> 45 #include <sys/sysctl.h> 46 #include <sys/pool.h> 47 #include <sys/task.h> 48 49 #include <net/if.h> 50 #include <net/if_var.h> 51 #include <net/if_dl.h> 52 #include <net/route.h> 53 #include <net/netisr.h> 54 55 #include <netinet/in.h> 56 #include <netinet/in_systm.h> 57 #include <netinet/if_ether.h> 58 #include <netinet/ip.h> 59 #include <netinet/in_pcb.h> 60 #include <netinet/in_var.h> 61 #include <netinet/ip_var.h> 62 #include <netinet/ip_icmp.h> 63 64 #if NPF > 0 65 #include <net/pfvar.h> 66 #endif 67 68 #ifdef MROUTING 69 #include <netinet/ip_mroute.h> 70 #endif 71 72 #ifdef IPSEC 73 #include <netinet/ip_ipsp.h> 74 #endif /* IPSEC */ 75 76 #if NCARP > 0 77 #include <net/if_types.h> 78 #include <netinet/ip_carp.h> 79 #endif 80 81 struct ipqhead ipq; 82 83 int encdebug = 0; 84 int ipsec_keep_invalid = IPSEC_DEFAULT_EMBRYONIC_SA_TIMEOUT; 85 int ipsec_require_pfs = IPSEC_DEFAULT_PFS; 86 int ipsec_soft_allocations = IPSEC_DEFAULT_SOFT_ALLOCATIONS; 87 int ipsec_exp_allocations = IPSEC_DEFAULT_EXP_ALLOCATIONS; 88 int ipsec_soft_bytes = IPSEC_DEFAULT_SOFT_BYTES; 89 int ipsec_exp_bytes = IPSEC_DEFAULT_EXP_BYTES; 90 int ipsec_soft_timeout = IPSEC_DEFAULT_SOFT_TIMEOUT; 91 int ipsec_exp_timeout = IPSEC_DEFAULT_EXP_TIMEOUT; 92 int ipsec_soft_first_use = IPSEC_DEFAULT_SOFT_FIRST_USE; 93 int ipsec_exp_first_use = IPSEC_DEFAULT_EXP_FIRST_USE; 94 int ipsec_expire_acquire = IPSEC_DEFAULT_EXPIRE_ACQUIRE; 95 char ipsec_def_enc[20]; 96 char ipsec_def_auth[20]; 97 char ipsec_def_comp[20]; 98 99 /* values controllable via sysctl */ 100 int ipforwarding = 0; 101 int ipmforwarding = 0; 102 int ipmultipath = 0; 103 int ipsendredirects = 1; 104 int ip_dosourceroute = 0; 105 int ip_defttl = IPDEFTTL; 106 int ip_mtudisc = 1; 107 u_int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 108 int ip_directedbcast = 0; 109 110 struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 111 112 /* Keep track of memory used for reassembly */ 113 int ip_maxqueue = 300; 114 int ip_frags = 0; 115 116 int *ipctl_vars[IPCTL_MAXID] = IPCTL_VARS; 117 118 struct niqueue ipintrq = NIQUEUE_INITIALIZER(IFQ_MAXLEN, NETISR_IP); 119 120 struct pool ipqent_pool; 121 struct pool ipq_pool; 122 123 struct ipstat ipstat; 124 125 static struct mbuf_queue ipsend_mq; 126 127 void ip_ours(struct mbuf *); 128 int ip_dooptions(struct mbuf *, struct ifnet *); 129 int in_ouraddr(struct mbuf *, struct ifnet *, struct rtentry **); 130 void ip_forward(struct mbuf *, struct ifnet *, struct rtentry *, int); 131 #ifdef IPSEC 132 int ip_input_ipsec_fwd_check(struct mbuf *, int); 133 int ip_input_ipsec_ours_check(struct mbuf *, int); 134 #endif /* IPSEC */ 135 136 static void ip_send_dispatch(void *); 137 static struct task ipsend_task = TASK_INITIALIZER(ip_send_dispatch, &ipsend_mq); 138 /* 139 * Used to save the IP options in case a protocol wants to respond 140 * to an incoming packet over the same route if the packet got here 141 * using IP source routing. This allows connection establishment and 142 * maintenance when the remote end is on a network that is not known 143 * to us. 144 */ 145 struct ip_srcrt { 146 int isr_nhops; /* number of hops */ 147 struct in_addr isr_dst; /* final destination */ 148 char isr_nop; /* one NOP to align */ 149 char isr_hdr[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN & OFFSET */ 150 struct in_addr isr_routes[MAX_IPOPTLEN/sizeof(struct in_addr)]; 151 }; 152 153 void save_rte(struct mbuf *, u_char *, struct in_addr); 154 155 /* 156 * IP initialization: fill in IP protocol switch table. 157 * All protocols not implemented in kernel go to raw IP protocol handler. 158 */ 159 void 160 ip_init(void) 161 { 162 struct protosw *pr; 163 int i; 164 const u_int16_t defbaddynamicports_tcp[] = DEFBADDYNAMICPORTS_TCP; 165 const u_int16_t defbaddynamicports_udp[] = DEFBADDYNAMICPORTS_UDP; 166 const u_int16_t defrootonlyports_tcp[] = DEFROOTONLYPORTS_TCP; 167 const u_int16_t defrootonlyports_udp[] = DEFROOTONLYPORTS_UDP; 168 169 pool_init(&ipqent_pool, sizeof(struct ipqent), 0, 170 IPL_SOFTNET, 0, "ipqe", NULL); 171 pool_init(&ipq_pool, sizeof(struct ipq), 0, 172 IPL_SOFTNET, 0, "ipq", NULL); 173 174 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 175 if (pr == NULL) 176 panic("ip_init"); 177 for (i = 0; i < IPPROTO_MAX; i++) 178 ip_protox[i] = pr - inetsw; 179 for (pr = inetdomain.dom_protosw; 180 pr < inetdomain.dom_protoswNPROTOSW; pr++) 181 if (pr->pr_domain->dom_family == PF_INET && 182 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW && 183 pr->pr_protocol < IPPROTO_MAX) 184 ip_protox[pr->pr_protocol] = pr - inetsw; 185 LIST_INIT(&ipq); 186 if (ip_mtudisc != 0) 187 ip_mtudisc_timeout_q = 188 rt_timer_queue_create(ip_mtudisc_timeout); 189 190 /* Fill in list of ports not to allocate dynamically. */ 191 memset(&baddynamicports, 0, sizeof(baddynamicports)); 192 for (i = 0; defbaddynamicports_tcp[i] != 0; i++) 193 DP_SET(baddynamicports.tcp, defbaddynamicports_tcp[i]); 194 for (i = 0; defbaddynamicports_udp[i] != 0; i++) 195 DP_SET(baddynamicports.udp, defbaddynamicports_udp[i]); 196 197 /* Fill in list of ports only root can bind to. */ 198 memset(&rootonlyports, 0, sizeof(rootonlyports)); 199 for (i = 0; defrootonlyports_tcp[i] != 0; i++) 200 DP_SET(rootonlyports.tcp, defrootonlyports_tcp[i]); 201 for (i = 0; defrootonlyports_udp[i] != 0; i++) 202 DP_SET(rootonlyports.udp, defrootonlyports_udp[i]); 203 204 strlcpy(ipsec_def_enc, IPSEC_DEFAULT_DEF_ENC, sizeof(ipsec_def_enc)); 205 strlcpy(ipsec_def_auth, IPSEC_DEFAULT_DEF_AUTH, sizeof(ipsec_def_auth)); 206 strlcpy(ipsec_def_comp, IPSEC_DEFAULT_DEF_COMP, sizeof(ipsec_def_comp)); 207 208 mq_init(&ipsend_mq, 64, IPL_SOFTNET); 209 } 210 211 void 212 ipintr(void) 213 { 214 struct mbuf *m; 215 216 /* 217 * Get next datagram off input queue and get IP header 218 * in first mbuf. 219 */ 220 while ((m = niq_dequeue(&ipintrq)) != NULL) { 221 #ifdef DIAGNOSTIC 222 if ((m->m_flags & M_PKTHDR) == 0) 223 panic("ipintr no HDR"); 224 #endif 225 ipv4_input(m); 226 } 227 } 228 229 /* 230 * IPv4 input routine. 231 * 232 * Checksum and byte swap header. Process options. Forward or deliver. 233 */ 234 void 235 ipv4_input(struct mbuf *m) 236 { 237 struct ifnet *ifp; 238 struct rtentry *rt = NULL; 239 struct ip *ip; 240 int hlen, len; 241 #if defined(MROUTING) || defined(IPSEC) 242 int rv; 243 #endif 244 in_addr_t pfrdr = 0; 245 246 ifp = if_get(m->m_pkthdr.ph_ifidx); 247 if (ifp == NULL) 248 goto bad; 249 250 ipstat.ips_total++; 251 if (m->m_len < sizeof (struct ip) && 252 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 253 ipstat.ips_toosmall++; 254 goto out; 255 } 256 ip = mtod(m, struct ip *); 257 if (ip->ip_v != IPVERSION) { 258 ipstat.ips_badvers++; 259 goto bad; 260 } 261 hlen = ip->ip_hl << 2; 262 if (hlen < sizeof(struct ip)) { /* minimum header length */ 263 ipstat.ips_badhlen++; 264 goto bad; 265 } 266 if (hlen > m->m_len) { 267 if ((m = m_pullup(m, hlen)) == NULL) { 268 ipstat.ips_badhlen++; 269 goto out; 270 } 271 ip = mtod(m, struct ip *); 272 } 273 274 /* 127/8 must not appear on wire - RFC1122 */ 275 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 276 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 277 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 278 ipstat.ips_badaddr++; 279 goto bad; 280 } 281 } 282 283 if ((m->m_pkthdr.csum_flags & M_IPV4_CSUM_IN_OK) == 0) { 284 if (m->m_pkthdr.csum_flags & M_IPV4_CSUM_IN_BAD) { 285 ipstat.ips_badsum++; 286 goto bad; 287 } 288 289 ipstat.ips_inswcsum++; 290 if (in_cksum(m, hlen) != 0) { 291 ipstat.ips_badsum++; 292 goto bad; 293 } 294 } 295 296 /* Retrieve the packet length. */ 297 len = ntohs(ip->ip_len); 298 299 /* 300 * Convert fields to host representation. 301 */ 302 if (len < hlen) { 303 ipstat.ips_badlen++; 304 goto bad; 305 } 306 307 /* 308 * Check that the amount of data in the buffers 309 * is at least as much as the IP header would have us expect. 310 * Trim mbufs if longer than we expect. 311 * Drop packet if shorter than we expect. 312 */ 313 if (m->m_pkthdr.len < len) { 314 ipstat.ips_tooshort++; 315 goto bad; 316 } 317 if (m->m_pkthdr.len > len) { 318 if (m->m_len == m->m_pkthdr.len) { 319 m->m_len = len; 320 m->m_pkthdr.len = len; 321 } else 322 m_adj(m, len - m->m_pkthdr.len); 323 } 324 325 #if NCARP > 0 326 if (ifp->if_type == IFT_CARP && ip->ip_p != IPPROTO_ICMP && 327 carp_lsdrop(m, AF_INET, &ip->ip_src.s_addr, &ip->ip_dst.s_addr)) 328 goto bad; 329 #endif 330 331 #if NPF > 0 332 /* 333 * Packet filter 334 */ 335 pfrdr = ip->ip_dst.s_addr; 336 if (pf_test(AF_INET, PF_IN, ifp, &m) != PF_PASS) 337 goto bad; 338 if (m == NULL) 339 goto out; 340 341 ip = mtod(m, struct ip *); 342 hlen = ip->ip_hl << 2; 343 pfrdr = (pfrdr != ip->ip_dst.s_addr); 344 #endif 345 346 /* 347 * Process options and, if not destined for us, 348 * ship it on. ip_dooptions returns 1 when an 349 * error was detected (causing an icmp message 350 * to be sent and the original packet to be freed). 351 */ 352 if (hlen > sizeof (struct ip) && ip_dooptions(m, ifp)) { 353 goto out; 354 } 355 356 if (in_ouraddr(m, ifp, &rt)) { 357 ip_ours(m); 358 goto out; 359 } 360 361 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 362 /* 363 * Make sure M_MCAST is set. It should theoretically 364 * already be there, but let's play safe because upper 365 * layers check for this flag. 366 */ 367 m->m_flags |= M_MCAST; 368 369 #ifdef MROUTING 370 if (ipmforwarding && ip_mrouter) { 371 if (m->m_flags & M_EXT) { 372 if ((m = m_pullup(m, hlen)) == NULL) { 373 ipstat.ips_toosmall++; 374 goto out; 375 } 376 ip = mtod(m, struct ip *); 377 } 378 /* 379 * If we are acting as a multicast router, all 380 * incoming multicast packets are passed to the 381 * kernel-level multicast forwarding function. 382 * The packet is returned (relatively) intact; if 383 * ip_mforward() returns a non-zero value, the packet 384 * must be discarded, else it may be accepted below. 385 * 386 * (The IP ident field is put in the same byte order 387 * as expected when ip_mforward() is called from 388 * ip_output().) 389 */ 390 KERNEL_LOCK(); 391 rv = ip_mforward(m, ifp); 392 KERNEL_UNLOCK(); 393 if (rv != 0) { 394 ipstat.ips_cantforward++; 395 goto bad; 396 } 397 398 /* 399 * The process-level routing daemon needs to receive 400 * all multicast IGMP packets, whether or not this 401 * host belongs to their destination groups. 402 */ 403 if (ip->ip_p == IPPROTO_IGMP) { 404 ip_ours(m); 405 goto out; 406 } 407 ipstat.ips_forward++; 408 } 409 #endif 410 /* 411 * See if we belong to the destination multicast group on the 412 * arrival interface. 413 */ 414 if (!in_hasmulti(&ip->ip_dst, ifp)) { 415 ipstat.ips_notmember++; 416 if (!IN_LOCAL_GROUP(ip->ip_dst.s_addr)) 417 ipstat.ips_cantforward++; 418 goto bad; 419 } 420 ip_ours(m); 421 goto out; 422 } 423 424 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 425 ip->ip_dst.s_addr == INADDR_ANY) { 426 ip_ours(m); 427 goto out; 428 } 429 430 #if NCARP > 0 431 if (ifp->if_type == IFT_CARP && ip->ip_p == IPPROTO_ICMP && 432 carp_lsdrop(m, AF_INET, &ip->ip_src.s_addr, &ip->ip_dst.s_addr)) 433 goto bad; 434 #endif 435 /* 436 * Not for us; forward if possible and desirable. 437 */ 438 if (ipforwarding == 0) { 439 ipstat.ips_cantforward++; 440 goto bad; 441 } 442 #ifdef IPSEC 443 if (ipsec_in_use) { 444 KERNEL_LOCK(); 445 rv = ip_input_ipsec_fwd_check(m, hlen); 446 KERNEL_UNLOCK(); 447 if (rv != 0) { 448 ipstat.ips_cantforward++; 449 goto bad; 450 } 451 /* 452 * Fall through, forward packet. Outbound IPsec policy 453 * checking will occur in ip_output(). 454 */ 455 } 456 #endif /* IPSEC */ 457 458 ip_forward(m, ifp, rt, pfrdr); 459 if_put(ifp); 460 return; 461 bad: 462 m_freem(m); 463 out: 464 rtfree(rt); 465 if_put(ifp); 466 } 467 468 /* 469 * IPv4 local-delivery routine. 470 * 471 * If fragmented try to reassemble. Pass to next level. 472 */ 473 void 474 ip_ours(struct mbuf *m) 475 { 476 struct ip *ip = mtod(m, struct ip *); 477 struct ipq *fp; 478 struct ipqent *ipqe; 479 int mff, hlen; 480 481 hlen = ip->ip_hl << 2; 482 483 /* pf might have modified stuff, might have to chksum */ 484 in_proto_cksum_out(m, NULL); 485 486 /* 487 * If offset or IP_MF are set, must reassemble. 488 * Otherwise, nothing need be done. 489 * (We could look in the reassembly queue to see 490 * if the packet was previously fragmented, 491 * but it's not worth the time; just let them time out.) 492 */ 493 if (ip->ip_off &~ htons(IP_DF | IP_RF)) { 494 if (m->m_flags & M_EXT) { /* XXX */ 495 if ((m = m_pullup(m, hlen)) == NULL) { 496 ipstat.ips_toosmall++; 497 return; 498 } 499 ip = mtod(m, struct ip *); 500 } 501 502 /* 503 * Look for queue of fragments 504 * of this datagram. 505 */ 506 LIST_FOREACH(fp, &ipq, ipq_q) 507 if (ip->ip_id == fp->ipq_id && 508 ip->ip_src.s_addr == fp->ipq_src.s_addr && 509 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 510 ip->ip_p == fp->ipq_p) 511 goto found; 512 fp = 0; 513 found: 514 515 /* 516 * Adjust ip_len to not reflect header, 517 * set ipqe_mff if more fragments are expected, 518 * convert offset of this to bytes. 519 */ 520 ip->ip_len = htons(ntohs(ip->ip_len) - hlen); 521 mff = (ip->ip_off & htons(IP_MF)) != 0; 522 if (mff) { 523 /* 524 * Make sure that fragments have a data length 525 * that's a non-zero multiple of 8 bytes. 526 */ 527 if (ntohs(ip->ip_len) == 0 || 528 (ntohs(ip->ip_len) & 0x7) != 0) { 529 ipstat.ips_badfrags++; 530 goto bad; 531 } 532 } 533 ip->ip_off = htons(ntohs(ip->ip_off) << 3); 534 535 /* 536 * If datagram marked as having more fragments 537 * or if this is not the first fragment, 538 * attempt reassembly; if it succeeds, proceed. 539 */ 540 if (mff || ip->ip_off) { 541 ipstat.ips_fragments++; 542 if (ip_frags + 1 > ip_maxqueue) { 543 ip_flush(); 544 ipstat.ips_rcvmemdrop++; 545 goto bad; 546 } 547 548 ipqe = pool_get(&ipqent_pool, PR_NOWAIT); 549 if (ipqe == NULL) { 550 ipstat.ips_rcvmemdrop++; 551 goto bad; 552 } 553 ip_frags++; 554 ipqe->ipqe_mff = mff; 555 ipqe->ipqe_m = m; 556 ipqe->ipqe_ip = ip; 557 m = ip_reass(ipqe, fp); 558 if (m == NULL) { 559 return; 560 } 561 ipstat.ips_reassembled++; 562 ip = mtod(m, struct ip *); 563 hlen = ip->ip_hl << 2; 564 ip->ip_len = htons(ntohs(ip->ip_len) + hlen); 565 } else 566 if (fp) 567 ip_freef(fp); 568 } 569 570 #ifdef IPSEC 571 if (ipsec_in_use) { 572 if (ip_input_ipsec_ours_check(m, hlen) != 0) { 573 ipstat.ips_cantforward++; 574 goto bad; 575 } 576 } 577 /* Otherwise, just fall through and deliver the packet */ 578 #endif /* IPSEC */ 579 580 /* 581 * Switch out to protocol's input routine. 582 */ 583 ipstat.ips_delivered++; 584 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, NULL, 0); 585 return; 586 bad: 587 m_freem(m); 588 } 589 590 int 591 in_ouraddr(struct mbuf *m, struct ifnet *ifp, struct rtentry **prt) 592 { 593 struct rtentry *rt; 594 struct ip *ip; 595 struct sockaddr_in sin; 596 int match = 0; 597 598 #if NPF > 0 599 switch (pf_ouraddr(m)) { 600 case 0: 601 return (0); 602 case 1: 603 return (1); 604 default: 605 /* pf does not know it */ 606 break; 607 } 608 #endif 609 610 ip = mtod(m, struct ip *); 611 612 memset(&sin, 0, sizeof(sin)); 613 sin.sin_len = sizeof(sin); 614 sin.sin_family = AF_INET; 615 sin.sin_addr = ip->ip_dst; 616 rt = rtalloc_mpath(sintosa(&sin), &ip->ip_src.s_addr, 617 m->m_pkthdr.ph_rtableid); 618 if (rtisvalid(rt)) { 619 if (ISSET(rt->rt_flags, RTF_LOCAL)) 620 match = 1; 621 622 /* 623 * If directedbcast is enabled we only consider it local 624 * if it is received on the interface with that address. 625 */ 626 if (ISSET(rt->rt_flags, RTF_BROADCAST) && 627 (!ip_directedbcast || rt->rt_ifidx == ifp->if_index)) { 628 match = 1; 629 630 /* Make sure M_BCAST is set */ 631 m->m_flags |= M_BCAST; 632 } 633 } 634 *prt = rt; 635 636 if (!match) { 637 struct ifaddr *ifa; 638 639 /* 640 * No local address or broadcast address found, so check for 641 * ancient classful broadcast addresses. 642 * It must have been broadcast on the link layer, and for an 643 * address on the interface it was received on. 644 */ 645 if (!ISSET(m->m_flags, M_BCAST) || 646 !IN_CLASSFULBROADCAST(ip->ip_dst.s_addr, ip->ip_dst.s_addr)) 647 return (0); 648 649 if (ifp->if_rdomain != rtable_l2(m->m_pkthdr.ph_rtableid)) 650 return (0); 651 /* 652 * The check in the loop assumes you only rx a packet on an UP 653 * interface, and that M_BCAST will only be set on a BROADCAST 654 * interface. 655 */ 656 KERNEL_LOCK(); 657 TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) { 658 if (ifa->ifa_addr->sa_family != AF_INET) 659 continue; 660 661 if (IN_CLASSFULBROADCAST(ip->ip_dst.s_addr, 662 ifatoia(ifa)->ia_addr.sin_addr.s_addr)) { 663 match = 1; 664 break; 665 } 666 } 667 KERNEL_UNLOCK(); 668 } 669 670 return (match); 671 } 672 673 #ifdef IPSEC 674 int 675 ip_input_ipsec_fwd_check(struct mbuf *m, int hlen) 676 { 677 struct tdb *tdb; 678 struct tdb_ident *tdbi; 679 struct m_tag *mtag; 680 int error = 0; 681 682 /* 683 * IPsec policy check for forwarded packets. Look at 684 * inner-most IPsec SA used. 685 */ 686 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 687 if (mtag != NULL) { 688 tdbi = (struct tdb_ident *)(mtag + 1); 689 tdb = gettdb(tdbi->rdomain, tdbi->spi, &tdbi->dst, tdbi->proto); 690 } else 691 tdb = NULL; 692 ipsp_spd_lookup(m, AF_INET, hlen, &error, IPSP_DIRECTION_IN, tdb, NULL, 693 0); 694 695 return error; 696 } 697 698 int 699 ip_input_ipsec_ours_check(struct mbuf *m, int hlen) 700 { 701 struct ip *ip = mtod(m, struct ip *); 702 struct tdb *tdb; 703 struct tdb_ident *tdbi; 704 struct m_tag *mtag; 705 int error = 0; 706 707 /* 708 * If it's a protected packet for us, skip the policy check. 709 * That's because we really only care about the properties of 710 * the protected packet, and not the intermediate versions. 711 * While this is not the most paranoid setting, it allows 712 * some flexibility in handling nested tunnels (in setting up 713 * the policies). 714 */ 715 if ((ip->ip_p == IPPROTO_ESP) || (ip->ip_p == IPPROTO_AH) || 716 (ip->ip_p == IPPROTO_IPCOMP)) 717 return 0; 718 719 /* 720 * If the protected packet was tunneled, then we need to 721 * verify the protected packet's information, not the 722 * external headers. Thus, skip the policy lookup for the 723 * external packet, and keep the IPsec information linked on 724 * the packet header (the encapsulation routines know how 725 * to deal with that). 726 */ 727 if ((ip->ip_p == IPPROTO_IPIP) || (ip->ip_p == IPPROTO_IPV6)) 728 return 0; 729 730 /* 731 * If the protected packet is TCP or UDP, we'll do the 732 * policy check in the respective input routine, so we can 733 * check for bypass sockets. 734 */ 735 if ((ip->ip_p == IPPROTO_TCP) || (ip->ip_p == IPPROTO_UDP)) 736 return 0; 737 738 /* 739 * IPsec policy check for local-delivery packets. Look at the 740 * inner-most SA that protected the packet. This is in fact 741 * a bit too restrictive (it could end up causing packets to 742 * be dropped that semantically follow the policy, e.g., in 743 * certain SA-bundle configurations); but the alternative is 744 * very complicated (and requires keeping track of what 745 * kinds of tunneling headers have been seen in-between the 746 * IPsec headers), and I don't think we lose much functionality 747 * that's needed in the real world (who uses bundles anyway ?). 748 */ 749 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 750 if (mtag) { 751 tdbi = (struct tdb_ident *)(mtag + 1); 752 tdb = gettdb(tdbi->rdomain, tdbi->spi, &tdbi->dst, 753 tdbi->proto); 754 } else 755 tdb = NULL; 756 ipsp_spd_lookup(m, AF_INET, hlen, &error, IPSP_DIRECTION_IN, 757 tdb, NULL, 0); 758 759 return error; 760 } 761 #endif /* IPSEC */ 762 763 /* 764 * Take incoming datagram fragment and try to 765 * reassemble it into whole datagram. If a chain for 766 * reassembly of this datagram already exists, then it 767 * is given as fp; otherwise have to make a chain. 768 */ 769 struct mbuf * 770 ip_reass(struct ipqent *ipqe, struct ipq *fp) 771 { 772 struct mbuf *m = ipqe->ipqe_m; 773 struct ipqent *nq, *p, *q; 774 struct ip *ip; 775 struct mbuf *t; 776 int hlen = ipqe->ipqe_ip->ip_hl << 2; 777 int i, next; 778 u_int8_t ecn, ecn0; 779 780 /* 781 * Presence of header sizes in mbufs 782 * would confuse code below. 783 */ 784 m->m_data += hlen; 785 m->m_len -= hlen; 786 787 /* 788 * If first fragment to arrive, create a reassembly queue. 789 */ 790 if (fp == NULL) { 791 fp = pool_get(&ipq_pool, PR_NOWAIT); 792 if (fp == NULL) 793 goto dropfrag; 794 LIST_INSERT_HEAD(&ipq, fp, ipq_q); 795 fp->ipq_ttl = IPFRAGTTL; 796 fp->ipq_p = ipqe->ipqe_ip->ip_p; 797 fp->ipq_id = ipqe->ipqe_ip->ip_id; 798 LIST_INIT(&fp->ipq_fragq); 799 fp->ipq_src = ipqe->ipqe_ip->ip_src; 800 fp->ipq_dst = ipqe->ipqe_ip->ip_dst; 801 p = NULL; 802 goto insert; 803 } 804 805 /* 806 * Handle ECN by comparing this segment with the first one; 807 * if CE is set, do not lose CE. 808 * drop if CE and not-ECT are mixed for the same packet. 809 */ 810 ecn = ipqe->ipqe_ip->ip_tos & IPTOS_ECN_MASK; 811 ecn0 = LIST_FIRST(&fp->ipq_fragq)->ipqe_ip->ip_tos & IPTOS_ECN_MASK; 812 if (ecn == IPTOS_ECN_CE) { 813 if (ecn0 == IPTOS_ECN_NOTECT) 814 goto dropfrag; 815 if (ecn0 != IPTOS_ECN_CE) 816 LIST_FIRST(&fp->ipq_fragq)->ipqe_ip->ip_tos |= IPTOS_ECN_CE; 817 } 818 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 819 goto dropfrag; 820 821 /* 822 * Find a segment which begins after this one does. 823 */ 824 for (p = NULL, q = LIST_FIRST(&fp->ipq_fragq); q != NULL; 825 p = q, q = LIST_NEXT(q, ipqe_q)) 826 if (ntohs(q->ipqe_ip->ip_off) > ntohs(ipqe->ipqe_ip->ip_off)) 827 break; 828 829 /* 830 * If there is a preceding segment, it may provide some of 831 * our data already. If so, drop the data from the incoming 832 * segment. If it provides all of our data, drop us. 833 */ 834 if (p != NULL) { 835 i = ntohs(p->ipqe_ip->ip_off) + ntohs(p->ipqe_ip->ip_len) - 836 ntohs(ipqe->ipqe_ip->ip_off); 837 if (i > 0) { 838 if (i >= ntohs(ipqe->ipqe_ip->ip_len)) 839 goto dropfrag; 840 m_adj(ipqe->ipqe_m, i); 841 ipqe->ipqe_ip->ip_off = 842 htons(ntohs(ipqe->ipqe_ip->ip_off) + i); 843 ipqe->ipqe_ip->ip_len = 844 htons(ntohs(ipqe->ipqe_ip->ip_len) - i); 845 } 846 } 847 848 /* 849 * While we overlap succeeding segments trim them or, 850 * if they are completely covered, dequeue them. 851 */ 852 for (; q != NULL && 853 ntohs(ipqe->ipqe_ip->ip_off) + ntohs(ipqe->ipqe_ip->ip_len) > 854 ntohs(q->ipqe_ip->ip_off); q = nq) { 855 i = (ntohs(ipqe->ipqe_ip->ip_off) + 856 ntohs(ipqe->ipqe_ip->ip_len)) - ntohs(q->ipqe_ip->ip_off); 857 if (i < ntohs(q->ipqe_ip->ip_len)) { 858 q->ipqe_ip->ip_len = 859 htons(ntohs(q->ipqe_ip->ip_len) - i); 860 q->ipqe_ip->ip_off = 861 htons(ntohs(q->ipqe_ip->ip_off) + i); 862 m_adj(q->ipqe_m, i); 863 break; 864 } 865 nq = LIST_NEXT(q, ipqe_q); 866 m_freem(q->ipqe_m); 867 LIST_REMOVE(q, ipqe_q); 868 pool_put(&ipqent_pool, q); 869 ip_frags--; 870 } 871 872 insert: 873 /* 874 * Stick new segment in its place; 875 * check for complete reassembly. 876 */ 877 if (p == NULL) { 878 LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); 879 } else { 880 LIST_INSERT_AFTER(p, ipqe, ipqe_q); 881 } 882 next = 0; 883 for (p = NULL, q = LIST_FIRST(&fp->ipq_fragq); q != NULL; 884 p = q, q = LIST_NEXT(q, ipqe_q)) { 885 if (ntohs(q->ipqe_ip->ip_off) != next) 886 return (0); 887 next += ntohs(q->ipqe_ip->ip_len); 888 } 889 if (p->ipqe_mff) 890 return (0); 891 892 /* 893 * Reassembly is complete. Check for a bogus message size and 894 * concatenate fragments. 895 */ 896 q = LIST_FIRST(&fp->ipq_fragq); 897 ip = q->ipqe_ip; 898 if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) { 899 ipstat.ips_toolong++; 900 ip_freef(fp); 901 return (0); 902 } 903 m = q->ipqe_m; 904 t = m->m_next; 905 m->m_next = 0; 906 m_cat(m, t); 907 nq = LIST_NEXT(q, ipqe_q); 908 pool_put(&ipqent_pool, q); 909 ip_frags--; 910 for (q = nq; q != NULL; q = nq) { 911 t = q->ipqe_m; 912 nq = LIST_NEXT(q, ipqe_q); 913 pool_put(&ipqent_pool, q); 914 ip_frags--; 915 m_cat(m, t); 916 } 917 918 /* 919 * Create header for new ip packet by 920 * modifying header of first packet; 921 * dequeue and discard fragment reassembly header. 922 * Make header visible. 923 */ 924 ip->ip_len = htons(next); 925 ip->ip_src = fp->ipq_src; 926 ip->ip_dst = fp->ipq_dst; 927 LIST_REMOVE(fp, ipq_q); 928 pool_put(&ipq_pool, fp); 929 m->m_len += (ip->ip_hl << 2); 930 m->m_data -= (ip->ip_hl << 2); 931 /* some debugging cruft by sklower, below, will go away soon */ 932 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 933 int plen = 0; 934 for (t = m; t; t = t->m_next) 935 plen += t->m_len; 936 m->m_pkthdr.len = plen; 937 } 938 return (m); 939 940 dropfrag: 941 ipstat.ips_fragdropped++; 942 m_freem(m); 943 pool_put(&ipqent_pool, ipqe); 944 ip_frags--; 945 return (0); 946 } 947 948 /* 949 * Free a fragment reassembly header and all 950 * associated datagrams. 951 */ 952 void 953 ip_freef(struct ipq *fp) 954 { 955 struct ipqent *q, *p; 956 957 for (q = LIST_FIRST(&fp->ipq_fragq); q != NULL; q = p) { 958 p = LIST_NEXT(q, ipqe_q); 959 m_freem(q->ipqe_m); 960 LIST_REMOVE(q, ipqe_q); 961 pool_put(&ipqent_pool, q); 962 ip_frags--; 963 } 964 LIST_REMOVE(fp, ipq_q); 965 pool_put(&ipq_pool, fp); 966 } 967 968 /* 969 * IP timer processing; 970 * if a timer expires on a reassembly queue, discard it. 971 * clear the forwarding cache, there might be a better route. 972 */ 973 void 974 ip_slowtimo(void) 975 { 976 struct ipq *fp, *nfp; 977 int s = splsoftnet(); 978 979 for (fp = LIST_FIRST(&ipq); fp != NULL; fp = nfp) { 980 nfp = LIST_NEXT(fp, ipq_q); 981 if (--fp->ipq_ttl == 0) { 982 ipstat.ips_fragtimeout++; 983 ip_freef(fp); 984 } 985 } 986 splx(s); 987 } 988 989 /* 990 * Drain off all datagram fragments. 991 */ 992 void 993 ip_drain(void) 994 { 995 while (!LIST_EMPTY(&ipq)) { 996 ipstat.ips_fragdropped++; 997 ip_freef(LIST_FIRST(&ipq)); 998 } 999 } 1000 1001 /* 1002 * Flush a bunch of datagram fragments, till we are down to 75%. 1003 */ 1004 void 1005 ip_flush(void) 1006 { 1007 int max = 50; 1008 1009 /* ipq already locked */ 1010 while (!LIST_EMPTY(&ipq) && ip_frags > ip_maxqueue * 3 / 4 && --max) { 1011 ipstat.ips_fragdropped++; 1012 ip_freef(LIST_FIRST(&ipq)); 1013 } 1014 } 1015 1016 /* 1017 * Do option processing on a datagram, 1018 * possibly discarding it if bad options are encountered, 1019 * or forwarding it if source-routed. 1020 * Returns 1 if packet has been forwarded/freed, 1021 * 0 if the packet should be processed further. 1022 */ 1023 int 1024 ip_dooptions(struct mbuf *m, struct ifnet *ifp) 1025 { 1026 struct ip *ip = mtod(m, struct ip *); 1027 unsigned int rtableid = m->m_pkthdr.ph_rtableid; 1028 struct rtentry *rt; 1029 struct sockaddr_in ipaddr; 1030 u_char *cp; 1031 struct ip_timestamp ipt; 1032 struct in_ifaddr *ia; 1033 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1034 struct in_addr sin, dst; 1035 u_int32_t ntime; 1036 1037 dst = ip->ip_dst; 1038 cp = (u_char *)(ip + 1); 1039 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1040 1041 KERNEL_LOCK(); 1042 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1043 opt = cp[IPOPT_OPTVAL]; 1044 if (opt == IPOPT_EOL) 1045 break; 1046 if (opt == IPOPT_NOP) 1047 optlen = 1; 1048 else { 1049 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1050 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1051 goto bad; 1052 } 1053 optlen = cp[IPOPT_OLEN]; 1054 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1055 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1056 goto bad; 1057 } 1058 } 1059 1060 switch (opt) { 1061 1062 default: 1063 break; 1064 1065 /* 1066 * Source routing with record. 1067 * Find interface with current destination address. 1068 * If none on this machine then drop if strictly routed, 1069 * or do nothing if loosely routed. 1070 * Record interface address and bring up next address 1071 * component. If strictly routed make sure next 1072 * address is on directly accessible net. 1073 */ 1074 case IPOPT_LSRR: 1075 case IPOPT_SSRR: 1076 if (!ip_dosourceroute) { 1077 type = ICMP_UNREACH; 1078 code = ICMP_UNREACH_SRCFAIL; 1079 goto bad; 1080 } 1081 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1082 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1083 goto bad; 1084 } 1085 memset(&ipaddr, 0, sizeof(ipaddr)); 1086 ipaddr.sin_family = AF_INET; 1087 ipaddr.sin_len = sizeof(ipaddr); 1088 ipaddr.sin_addr = ip->ip_dst; 1089 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr), 1090 m->m_pkthdr.ph_rtableid)); 1091 if (ia == NULL) { 1092 if (opt == IPOPT_SSRR) { 1093 type = ICMP_UNREACH; 1094 code = ICMP_UNREACH_SRCFAIL; 1095 goto bad; 1096 } 1097 /* 1098 * Loose routing, and not at next destination 1099 * yet; nothing to do except forward. 1100 */ 1101 break; 1102 } 1103 off--; /* 0 origin */ 1104 if ((off + sizeof(struct in_addr)) > optlen) { 1105 /* 1106 * End of source route. Should be for us. 1107 */ 1108 save_rte(m, cp, ip->ip_src); 1109 break; 1110 } 1111 1112 /* 1113 * locate outgoing interface 1114 */ 1115 memset(&ipaddr, 0, sizeof(ipaddr)); 1116 ipaddr.sin_family = AF_INET; 1117 ipaddr.sin_len = sizeof(ipaddr); 1118 memcpy(&ipaddr.sin_addr, cp + off, 1119 sizeof(ipaddr.sin_addr)); 1120 if (opt == IPOPT_SSRR) { 1121 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(&ipaddr), 1122 m->m_pkthdr.ph_rtableid))) == NULL) 1123 ia = ifatoia(ifa_ifwithnet(sintosa(&ipaddr), 1124 m->m_pkthdr.ph_rtableid)); 1125 if (ia == NULL) { 1126 type = ICMP_UNREACH; 1127 code = ICMP_UNREACH_SRCFAIL; 1128 goto bad; 1129 } 1130 memcpy(cp + off, &ia->ia_addr.sin_addr, 1131 sizeof(struct in_addr)); 1132 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1133 } else { 1134 /* keep packet in the virtual instance */ 1135 rt = rtalloc(sintosa(&ipaddr), RT_RESOLVE, 1136 rtableid); 1137 if (!rtisvalid(rt)) { 1138 type = ICMP_UNREACH; 1139 code = ICMP_UNREACH_SRCFAIL; 1140 rtfree(rt); 1141 goto bad; 1142 } 1143 ia = ifatoia(rt->rt_ifa); 1144 memcpy(cp + off, &ia->ia_addr.sin_addr, 1145 sizeof(struct in_addr)); 1146 rtfree(rt); 1147 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1148 } 1149 ip->ip_dst = ipaddr.sin_addr; 1150 /* 1151 * Let ip_intr's mcast routing check handle mcast pkts 1152 */ 1153 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1154 break; 1155 1156 case IPOPT_RR: 1157 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1158 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1159 goto bad; 1160 } 1161 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1162 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1163 goto bad; 1164 } 1165 1166 /* 1167 * If no space remains, ignore. 1168 */ 1169 off--; /* 0 origin */ 1170 if ((off + sizeof(struct in_addr)) > optlen) 1171 break; 1172 memset(&ipaddr, 0, sizeof(ipaddr)); 1173 ipaddr.sin_family = AF_INET; 1174 ipaddr.sin_len = sizeof(ipaddr); 1175 ipaddr.sin_addr = ip->ip_dst; 1176 /* 1177 * locate outgoing interface; if we're the destination, 1178 * use the incoming interface (should be same). 1179 * Again keep the packet inside the virtual instance. 1180 */ 1181 rt = rtalloc(sintosa(&ipaddr), RT_RESOLVE, rtableid); 1182 if (!rtisvalid(rt)) { 1183 type = ICMP_UNREACH; 1184 code = ICMP_UNREACH_HOST; 1185 rtfree(rt); 1186 goto bad; 1187 } 1188 ia = ifatoia(rt->rt_ifa); 1189 memcpy(cp + off, &ia->ia_addr.sin_addr, 1190 sizeof(struct in_addr)); 1191 rtfree(rt); 1192 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1193 break; 1194 1195 case IPOPT_TS: 1196 code = cp - (u_char *)ip; 1197 if (optlen < sizeof(struct ip_timestamp)) 1198 goto bad; 1199 memcpy(&ipt, cp, sizeof(struct ip_timestamp)); 1200 if (ipt.ipt_ptr < 5 || ipt.ipt_len < 5) 1201 goto bad; 1202 if (ipt.ipt_ptr - 1 + sizeof(u_int32_t) > ipt.ipt_len) { 1203 if (++ipt.ipt_oflw == 0) 1204 goto bad; 1205 break; 1206 } 1207 memcpy(&sin, cp + ipt.ipt_ptr - 1, sizeof sin); 1208 switch (ipt.ipt_flg) { 1209 1210 case IPOPT_TS_TSONLY: 1211 break; 1212 1213 case IPOPT_TS_TSANDADDR: 1214 if (ipt.ipt_ptr - 1 + sizeof(u_int32_t) + 1215 sizeof(struct in_addr) > ipt.ipt_len) 1216 goto bad; 1217 memset(&ipaddr, 0, sizeof(ipaddr)); 1218 ipaddr.sin_family = AF_INET; 1219 ipaddr.sin_len = sizeof(ipaddr); 1220 ipaddr.sin_addr = dst; 1221 ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr), 1222 ifp)); 1223 if (ia == NULL) 1224 continue; 1225 memcpy(&sin, &ia->ia_addr.sin_addr, 1226 sizeof(struct in_addr)); 1227 ipt.ipt_ptr += sizeof(struct in_addr); 1228 break; 1229 1230 case IPOPT_TS_PRESPEC: 1231 if (ipt.ipt_ptr - 1 + sizeof(u_int32_t) + 1232 sizeof(struct in_addr) > ipt.ipt_len) 1233 goto bad; 1234 memset(&ipaddr, 0, sizeof(ipaddr)); 1235 ipaddr.sin_family = AF_INET; 1236 ipaddr.sin_len = sizeof(ipaddr); 1237 ipaddr.sin_addr = sin; 1238 if (ifa_ifwithaddr(sintosa(&ipaddr), 1239 m->m_pkthdr.ph_rtableid) == NULL) 1240 continue; 1241 ipt.ipt_ptr += sizeof(struct in_addr); 1242 break; 1243 1244 default: 1245 /* XXX can't take &ipt->ipt_flg */ 1246 code = (u_char *)&ipt.ipt_ptr - 1247 (u_char *)ip + 1; 1248 goto bad; 1249 } 1250 ntime = iptime(); 1251 memcpy(cp + ipt.ipt_ptr - 1, &ntime, sizeof(u_int32_t)); 1252 ipt.ipt_ptr += sizeof(u_int32_t); 1253 } 1254 } 1255 KERNEL_UNLOCK(); 1256 if (forward && ipforwarding) { 1257 ip_forward(m, ifp, NULL, 1); 1258 return (1); 1259 } 1260 return (0); 1261 bad: 1262 KERNEL_UNLOCK(); 1263 icmp_error(m, type, code, 0, 0); 1264 ipstat.ips_badoptions++; 1265 return (1); 1266 } 1267 1268 /* 1269 * Save incoming source route for use in replies, 1270 * to be picked up later by ip_srcroute if the receiver is interested. 1271 */ 1272 void 1273 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1274 { 1275 struct ip_srcrt *isr; 1276 struct m_tag *mtag; 1277 unsigned olen; 1278 1279 olen = option[IPOPT_OLEN]; 1280 if (olen > sizeof(isr->isr_hdr) + sizeof(isr->isr_routes)) 1281 return; 1282 1283 mtag = m_tag_get(PACKET_TAG_SRCROUTE, sizeof(*isr), M_NOWAIT); 1284 if (mtag == NULL) 1285 return; 1286 isr = (struct ip_srcrt *)(mtag + 1); 1287 1288 memcpy(isr->isr_hdr, option, olen); 1289 isr->isr_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1290 isr->isr_dst = dst; 1291 m_tag_prepend(m, mtag); 1292 } 1293 1294 /* 1295 * Retrieve incoming source route for use in replies, 1296 * in the same form used by setsockopt. 1297 * The first hop is placed before the options, will be removed later. 1298 */ 1299 struct mbuf * 1300 ip_srcroute(struct mbuf *m0) 1301 { 1302 struct in_addr *p, *q; 1303 struct mbuf *m; 1304 struct ip_srcrt *isr; 1305 struct m_tag *mtag; 1306 1307 if (!ip_dosourceroute) 1308 return (NULL); 1309 1310 mtag = m_tag_find(m0, PACKET_TAG_SRCROUTE, NULL); 1311 if (mtag == NULL) 1312 return (NULL); 1313 isr = (struct ip_srcrt *)(mtag + 1); 1314 1315 if (isr->isr_nhops == 0) 1316 return (NULL); 1317 m = m_get(M_DONTWAIT, MT_SOOPTS); 1318 if (m == NULL) 1319 return (NULL); 1320 1321 #define OPTSIZ (sizeof(isr->isr_nop) + sizeof(isr->isr_hdr)) 1322 1323 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + header) */ 1324 m->m_len = (isr->isr_nhops + 1) * sizeof(struct in_addr) + OPTSIZ; 1325 1326 /* 1327 * First save first hop for return route 1328 */ 1329 p = &(isr->isr_routes[isr->isr_nhops - 1]); 1330 *(mtod(m, struct in_addr *)) = *p--; 1331 1332 /* 1333 * Copy option fields and padding (nop) to mbuf. 1334 */ 1335 isr->isr_nop = IPOPT_NOP; 1336 isr->isr_hdr[IPOPT_OFFSET] = IPOPT_MINOFF; 1337 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &isr->isr_nop, 1338 OPTSIZ); 1339 q = (struct in_addr *)(mtod(m, caddr_t) + 1340 sizeof(struct in_addr) + OPTSIZ); 1341 #undef OPTSIZ 1342 /* 1343 * Record return path as an IP source route, 1344 * reversing the path (pointers are now aligned). 1345 */ 1346 while (p >= isr->isr_routes) { 1347 *q++ = *p--; 1348 } 1349 /* 1350 * Last hop goes to final destination. 1351 */ 1352 *q = isr->isr_dst; 1353 m_tag_delete(m0, (struct m_tag *)isr); 1354 return (m); 1355 } 1356 1357 /* 1358 * Strip out IP options, at higher level protocol in the kernel. 1359 */ 1360 void 1361 ip_stripoptions(struct mbuf *m) 1362 { 1363 int i; 1364 struct ip *ip = mtod(m, struct ip *); 1365 caddr_t opts; 1366 int olen; 1367 1368 olen = (ip->ip_hl<<2) - sizeof (struct ip); 1369 opts = (caddr_t)(ip + 1); 1370 i = m->m_len - (sizeof (struct ip) + olen); 1371 memmove(opts, opts + olen, i); 1372 m->m_len -= olen; 1373 if (m->m_flags & M_PKTHDR) 1374 m->m_pkthdr.len -= olen; 1375 ip->ip_hl = sizeof(struct ip) >> 2; 1376 ip->ip_len = htons(ntohs(ip->ip_len) - olen); 1377 } 1378 1379 int inetctlerrmap[PRC_NCMDS] = { 1380 0, 0, 0, 0, 1381 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1382 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1383 EMSGSIZE, EHOSTUNREACH, 0, 0, 1384 0, 0, 0, 0, 1385 ENOPROTOOPT 1386 }; 1387 1388 /* 1389 * Forward a packet. If some error occurs return the sender 1390 * an icmp packet. Note we can't always generate a meaningful 1391 * icmp message because icmp doesn't have a large enough repertoire 1392 * of codes and types. 1393 * 1394 * If not forwarding, just drop the packet. This could be confusing 1395 * if ipforwarding was zero but some routing protocol was advancing 1396 * us as a gateway to somewhere. However, we must let the routing 1397 * protocol deal with that. 1398 * 1399 * The srcrt parameter indicates whether the packet is being forwarded 1400 * via a source route. 1401 */ 1402 void 1403 ip_forward(struct mbuf *m, struct ifnet *ifp, struct rtentry *rt, int srcrt) 1404 { 1405 struct mbuf mfake, *mcopy = NULL; 1406 struct ip *ip = mtod(m, struct ip *); 1407 struct sockaddr_in *sin; 1408 struct route ro; 1409 int error, type = 0, code = 0, destmtu = 0, fake = 0, len; 1410 u_int32_t dest; 1411 1412 dest = 0; 1413 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1414 ipstat.ips_cantforward++; 1415 m_freem(m); 1416 goto freecopy; 1417 } 1418 if (ip->ip_ttl <= IPTTLDEC) { 1419 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1420 goto freecopy; 1421 } 1422 1423 sin = satosin(&ro.ro_dst); 1424 memset(sin, 0, sizeof(*sin)); 1425 sin->sin_family = AF_INET; 1426 sin->sin_len = sizeof(*sin); 1427 sin->sin_addr = ip->ip_dst; 1428 1429 if (!rtisvalid(rt)) { 1430 rtfree(rt); 1431 rt = rtalloc_mpath(sintosa(sin), &ip->ip_src.s_addr, 1432 m->m_pkthdr.ph_rtableid); 1433 if (rt == NULL) { 1434 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1435 return; 1436 } 1437 } 1438 1439 /* 1440 * Save at most 68 bytes of the packet in case 1441 * we need to generate an ICMP message to the src. 1442 * The data is saved in the mbuf on the stack that 1443 * acts as a temporary storage not intended to be 1444 * passed down the IP stack or to the mfree. 1445 */ 1446 memset(&mfake.m_hdr, 0, sizeof(mfake.m_hdr)); 1447 mfake.m_type = m->m_type; 1448 if (m_dup_pkthdr(&mfake, m, M_DONTWAIT) == 0) { 1449 mfake.m_data = mfake.m_pktdat; 1450 len = min(ntohs(ip->ip_len), 68); 1451 m_copydata(m, 0, len, mfake.m_pktdat); 1452 mfake.m_pkthdr.len = mfake.m_len = len; 1453 #if NPF > 0 1454 pf_pkt_unlink_state_key(&mfake); 1455 #endif /* NPF > 0 */ 1456 fake = 1; 1457 } 1458 1459 ip->ip_ttl -= IPTTLDEC; 1460 1461 /* 1462 * If forwarding packet using same interface that it came in on, 1463 * perhaps should send a redirect to sender to shortcut a hop. 1464 * Only send redirect if source is sending directly to us, 1465 * and if packet was not source routed (or has any options). 1466 * Also, don't send redirect if forwarding using a default route 1467 * or a route modified by a redirect. 1468 * Don't send redirect if we advertise destination's arp address 1469 * as ours (proxy arp). 1470 */ 1471 if ((rt->rt_ifidx == ifp->if_index) && 1472 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1473 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1474 ipsendredirects && !srcrt && 1475 !arpproxy(satosin(rt_key(rt))->sin_addr, m->m_pkthdr.ph_rtableid)) { 1476 if ((ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_netmask) == 1477 ifatoia(rt->rt_ifa)->ia_net) { 1478 if (rt->rt_flags & RTF_GATEWAY) 1479 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1480 else 1481 dest = ip->ip_dst.s_addr; 1482 /* Router requirements says to only send host redirects */ 1483 type = ICMP_REDIRECT; 1484 code = ICMP_REDIRECT_HOST; 1485 } 1486 } 1487 1488 ro.ro_rt = rt; 1489 ro.ro_tableid = m->m_pkthdr.ph_rtableid; 1490 error = ip_output(m, NULL, &ro, 1491 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1492 NULL, NULL, 0); 1493 rt = ro.ro_rt; 1494 if (error) 1495 ipstat.ips_cantforward++; 1496 else { 1497 ipstat.ips_forward++; 1498 if (type) 1499 ipstat.ips_redirectsent++; 1500 else 1501 goto freecopy; 1502 } 1503 if (!fake) 1504 goto freecopy; 1505 1506 switch (error) { 1507 1508 case 0: /* forwarded, but need redirect */ 1509 /* type, code set above */ 1510 break; 1511 1512 case ENETUNREACH: /* shouldn't happen, checked above */ 1513 case EHOSTUNREACH: 1514 case ENETDOWN: 1515 case EHOSTDOWN: 1516 default: 1517 type = ICMP_UNREACH; 1518 code = ICMP_UNREACH_HOST; 1519 break; 1520 1521 case EMSGSIZE: 1522 type = ICMP_UNREACH; 1523 code = ICMP_UNREACH_NEEDFRAG; 1524 1525 #ifdef IPSEC 1526 if (rt != NULL) { 1527 if (rt->rt_rmx.rmx_mtu) 1528 destmtu = rt->rt_rmx.rmx_mtu; 1529 else { 1530 struct ifnet *destifp; 1531 1532 destifp = if_get(rt->rt_ifidx); 1533 if (destifp != NULL) 1534 destmtu = destifp->if_mtu; 1535 if_put(destifp); 1536 } 1537 } 1538 #endif /*IPSEC*/ 1539 ipstat.ips_cantfrag++; 1540 break; 1541 1542 case EACCES: 1543 /* 1544 * pf(4) blocked the packet. There is no need to send an ICMP 1545 * packet back since pf(4) takes care of it. 1546 */ 1547 goto freecopy; 1548 case ENOBUFS: 1549 /* 1550 * a router should not generate ICMP_SOURCEQUENCH as 1551 * required in RFC1812 Requirements for IP Version 4 Routers. 1552 * source quench could be a big problem under DoS attacks, 1553 * or the underlying interface is rate-limited. 1554 */ 1555 goto freecopy; 1556 } 1557 1558 mcopy = m_copym(&mfake, 0, len, M_DONTWAIT); 1559 if (mcopy) 1560 icmp_error(mcopy, type, code, dest, destmtu); 1561 1562 freecopy: 1563 if (fake) 1564 m_tag_delete_chain(&mfake); 1565 rtfree(rt); 1566 } 1567 1568 int 1569 ip_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp, 1570 size_t newlen) 1571 { 1572 int s, error; 1573 #ifdef MROUTING 1574 extern int ip_mrtproto; 1575 extern struct mrtstat mrtstat; 1576 #endif 1577 1578 /* Almost all sysctl names at this level are terminal. */ 1579 if (namelen != 1 && name[0] != IPCTL_IFQUEUE) 1580 return (ENOTDIR); 1581 1582 switch (name[0]) { 1583 #ifdef notyet 1584 case IPCTL_DEFMTU: 1585 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu)); 1586 #endif 1587 case IPCTL_SOURCEROUTE: 1588 /* 1589 * Don't allow this to change in a secure environment. 1590 */ 1591 if (newp && securelevel > 0) 1592 return (EPERM); 1593 return (sysctl_int(oldp, oldlenp, newp, newlen, 1594 &ip_dosourceroute)); 1595 case IPCTL_MTUDISC: 1596 error = sysctl_int(oldp, oldlenp, newp, newlen, 1597 &ip_mtudisc); 1598 if (ip_mtudisc != 0 && ip_mtudisc_timeout_q == NULL) { 1599 ip_mtudisc_timeout_q = 1600 rt_timer_queue_create(ip_mtudisc_timeout); 1601 } else if (ip_mtudisc == 0 && ip_mtudisc_timeout_q != NULL) { 1602 s = splsoftnet(); 1603 rt_timer_queue_destroy(ip_mtudisc_timeout_q); 1604 ip_mtudisc_timeout_q = NULL; 1605 splx(s); 1606 } 1607 return error; 1608 case IPCTL_MTUDISCTIMEOUT: 1609 error = sysctl_int(oldp, oldlenp, newp, newlen, 1610 &ip_mtudisc_timeout); 1611 if (ip_mtudisc_timeout_q != NULL) { 1612 s = splsoftnet(); 1613 rt_timer_queue_change(ip_mtudisc_timeout_q, 1614 ip_mtudisc_timeout); 1615 splx(s); 1616 } 1617 return (error); 1618 case IPCTL_IPSEC_ENC_ALGORITHM: 1619 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1620 ipsec_def_enc, sizeof(ipsec_def_enc))); 1621 case IPCTL_IPSEC_AUTH_ALGORITHM: 1622 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1623 ipsec_def_auth, 1624 sizeof(ipsec_def_auth))); 1625 case IPCTL_IPSEC_IPCOMP_ALGORITHM: 1626 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1627 ipsec_def_comp, 1628 sizeof(ipsec_def_comp))); 1629 case IPCTL_IFQUEUE: 1630 return (sysctl_niq(name + 1, namelen - 1, 1631 oldp, oldlenp, newp, newlen, &ipintrq)); 1632 case IPCTL_STATS: 1633 return (sysctl_rdstruct(oldp, oldlenp, newp, 1634 &ipstat, sizeof(ipstat))); 1635 #ifdef MROUTING 1636 case IPCTL_MRTSTATS: 1637 return (sysctl_rdstruct(oldp, oldlenp, newp, 1638 &mrtstat, sizeof(mrtstat))); 1639 case IPCTL_MRTPROTO: 1640 return (sysctl_rdint(oldp, oldlenp, newp, ip_mrtproto)); 1641 case IPCTL_MRTMFC: 1642 if (newp) 1643 return (EPERM); 1644 return mrt_sysctl_mfc(oldp, oldlenp); 1645 case IPCTL_MRTVIF: 1646 if (newp) 1647 return (EPERM); 1648 return mrt_sysctl_vif(oldp, oldlenp); 1649 #else 1650 case IPCTL_MRTPROTO: 1651 case IPCTL_MRTSTATS: 1652 case IPCTL_MRTMFC: 1653 case IPCTL_MRTVIF: 1654 return (EOPNOTSUPP); 1655 #endif 1656 default: 1657 if (name[0] < IPCTL_MAXID) 1658 return (sysctl_int_arr(ipctl_vars, name, namelen, 1659 oldp, oldlenp, newp, newlen)); 1660 return (EOPNOTSUPP); 1661 } 1662 /* NOTREACHED */ 1663 } 1664 1665 void 1666 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1667 struct mbuf *m) 1668 { 1669 #ifdef SO_TIMESTAMP 1670 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1671 struct timeval tv; 1672 1673 microtime(&tv); 1674 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1675 SCM_TIMESTAMP, SOL_SOCKET); 1676 if (*mp) 1677 mp = &(*mp)->m_next; 1678 } 1679 #endif 1680 if (inp->inp_flags & INP_RECVDSTADDR) { 1681 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1682 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1683 if (*mp) 1684 mp = &(*mp)->m_next; 1685 } 1686 #ifdef notyet 1687 /* this code is broken and will probably never be fixed. */ 1688 /* options were tossed already */ 1689 if (inp->inp_flags & INP_RECVOPTS) { 1690 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1691 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1692 if (*mp) 1693 mp = &(*mp)->m_next; 1694 } 1695 /* ip_srcroute doesn't do what we want here, need to fix */ 1696 if (inp->inp_flags & INP_RECVRETOPTS) { 1697 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1698 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1699 if (*mp) 1700 mp = &(*mp)->m_next; 1701 } 1702 #endif 1703 if (inp->inp_flags & INP_RECVIF) { 1704 struct sockaddr_dl sdl; 1705 struct ifnet *ifp; 1706 1707 ifp = if_get(m->m_pkthdr.ph_ifidx); 1708 if (ifp == NULL || ifp->if_sadl == NULL) { 1709 memset(&sdl, 0, sizeof(sdl)); 1710 sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]); 1711 sdl.sdl_family = AF_LINK; 1712 sdl.sdl_index = ifp != NULL ? ifp->if_index : 0; 1713 sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0; 1714 *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len, 1715 IP_RECVIF, IPPROTO_IP); 1716 } else { 1717 *mp = sbcreatecontrol((caddr_t) ifp->if_sadl, 1718 ifp->if_sadl->sdl_len, IP_RECVIF, IPPROTO_IP); 1719 } 1720 if (*mp) 1721 mp = &(*mp)->m_next; 1722 if_put(ifp); 1723 } 1724 if (inp->inp_flags & INP_RECVTTL) { 1725 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1726 sizeof(u_int8_t), IP_RECVTTL, IPPROTO_IP); 1727 if (*mp) 1728 mp = &(*mp)->m_next; 1729 } 1730 if (inp->inp_flags & INP_RECVRTABLE) { 1731 u_int rtableid = inp->inp_rtableid; 1732 #if NPF > 0 1733 struct pf_divert *divert; 1734 1735 if (m && m->m_pkthdr.pf.flags & PF_TAG_DIVERTED && 1736 (divert = pf_find_divert(m)) != NULL) 1737 rtableid = divert->rdomain; 1738 #endif 1739 1740 *mp = sbcreatecontrol((caddr_t) &rtableid, 1741 sizeof(u_int), IP_RECVRTABLE, IPPROTO_IP); 1742 if (*mp) 1743 mp = &(*mp)->m_next; 1744 } 1745 } 1746 1747 void 1748 ip_send_dispatch(void *xmq) 1749 { 1750 struct mbuf_queue *mq = xmq; 1751 struct mbuf *m; 1752 struct mbuf_list ml; 1753 int s; 1754 1755 mq_delist(mq, &ml); 1756 KERNEL_LOCK(); 1757 s = splsoftnet(); 1758 while ((m = ml_dequeue(&ml)) != NULL) { 1759 ip_output(m, NULL, NULL, 0, NULL, NULL, 0); 1760 } 1761 splx(s); 1762 KERNEL_UNLOCK(); 1763 } 1764 1765 void 1766 ip_send(struct mbuf *m) 1767 { 1768 mq_enqueue(&ipsend_mq, m); 1769 task_add(softnettq, &ipsend_task); 1770 } 1771