1 /* $OpenBSD: ip_input.c,v 1.381 2022/08/29 14:43:56 bluhm 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/mutex.h> 43 #include <sys/protosw.h> 44 #include <sys/socket.h> 45 #include <sys/socketvar.h> 46 #include <sys/sysctl.h> 47 #include <sys/pool.h> 48 #include <sys/task.h> 49 50 #include <net/if.h> 51 #include <net/if_var.h> 52 #include <net/if_dl.h> 53 #include <net/route.h> 54 #include <net/netisr.h> 55 56 #include <netinet/in.h> 57 #include <netinet/in_systm.h> 58 #include <netinet/if_ether.h> 59 #include <netinet/ip.h> 60 #include <netinet/in_pcb.h> 61 #include <netinet/in_var.h> 62 #include <netinet/ip_var.h> 63 #include <netinet/ip_icmp.h> 64 #include <net/if_types.h> 65 66 #ifdef INET6 67 #include <netinet6/ip6_var.h> 68 #endif 69 70 #if NPF > 0 71 #include <net/pfvar.h> 72 #endif 73 74 #ifdef MROUTING 75 #include <netinet/ip_mroute.h> 76 #endif 77 78 #ifdef IPSEC 79 #include <netinet/ip_ipsp.h> 80 #endif /* IPSEC */ 81 82 #if NCARP > 0 83 #include <netinet/ip_carp.h> 84 #endif 85 86 /* values controllable via sysctl */ 87 int ipforwarding = 0; 88 int ipmforwarding = 0; 89 int ipmultipath = 0; 90 int ipsendredirects = 1; 91 int ip_dosourceroute = 0; 92 int ip_defttl = IPDEFTTL; 93 int ip_mtudisc = 1; 94 int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 95 int ip_directedbcast = 0; 96 97 /* Protects `ipq' and `ip_frags'. */ 98 struct mutex ipq_mutex = MUTEX_INITIALIZER(IPL_SOFTNET); 99 100 /* IP reassembly queue */ 101 LIST_HEAD(, ipq) ipq; 102 103 /* Keep track of memory used for reassembly */ 104 int ip_maxqueue = 300; 105 int ip_frags = 0; 106 107 const struct sysctl_bounded_args ipctl_vars[] = { 108 #ifdef MROUTING 109 { IPCTL_MRTPROTO, &ip_mrtproto, SYSCTL_INT_READONLY }, 110 #endif 111 { IPCTL_FORWARDING, &ipforwarding, 0, 2 }, 112 { IPCTL_SENDREDIRECTS, &ipsendredirects, 0, 1 }, 113 { IPCTL_DEFTTL, &ip_defttl, 0, 255 }, 114 { IPCTL_DIRECTEDBCAST, &ip_directedbcast, 0, 1 }, 115 { IPCTL_IPPORT_FIRSTAUTO, &ipport_firstauto, 0, 65535 }, 116 { IPCTL_IPPORT_LASTAUTO, &ipport_lastauto, 0, 65535 }, 117 { IPCTL_IPPORT_HIFIRSTAUTO, &ipport_hifirstauto, 0, 65535 }, 118 { IPCTL_IPPORT_HILASTAUTO, &ipport_hilastauto, 0, 65535 }, 119 { IPCTL_IPPORT_MAXQUEUE, &ip_maxqueue, 0, 10000 }, 120 { IPCTL_MFORWARDING, &ipmforwarding, 0, 1 }, 121 { IPCTL_MULTIPATH, &ipmultipath, 0, 1 }, 122 { IPCTL_ARPTIMEOUT, &arpt_keep, 0, INT_MAX }, 123 { IPCTL_ARPDOWN, &arpt_down, 0, INT_MAX }, 124 }; 125 126 struct niqueue ipintrq = NIQUEUE_INITIALIZER(IPQ_MAXLEN, NETISR_IP); 127 128 struct pool ipqent_pool; 129 struct pool ipq_pool; 130 131 struct cpumem *ipcounters; 132 133 int ip_sysctl_ipstat(void *, size_t *, void *); 134 135 static struct mbuf_queue ipsend_mq; 136 static struct mbuf_queue ipsendraw_mq; 137 138 extern struct niqueue arpinq; 139 140 int ip_ours(struct mbuf **, int *, int, int); 141 int ip_dooptions(struct mbuf *, struct ifnet *); 142 int in_ouraddr(struct mbuf *, struct ifnet *, struct rtentry **); 143 144 int ip_fragcheck(struct mbuf **, int *); 145 struct mbuf * ip_reass(struct ipqent *, struct ipq *); 146 void ip_freef(struct ipq *); 147 void ip_flush(void); 148 149 static void ip_send_dispatch(void *); 150 static void ip_sendraw_dispatch(void *); 151 static struct task ipsend_task = TASK_INITIALIZER(ip_send_dispatch, &ipsend_mq); 152 static struct task ipsendraw_task = 153 TASK_INITIALIZER(ip_sendraw_dispatch, &ipsendraw_mq); 154 155 /* 156 * Used to save the IP options in case a protocol wants to respond 157 * to an incoming packet over the same route if the packet got here 158 * using IP source routing. This allows connection establishment and 159 * maintenance when the remote end is on a network that is not known 160 * to us. 161 */ 162 struct ip_srcrt { 163 int isr_nhops; /* number of hops */ 164 struct in_addr isr_dst; /* final destination */ 165 char isr_nop; /* one NOP to align */ 166 char isr_hdr[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN & OFFSET */ 167 struct in_addr isr_routes[MAX_IPOPTLEN/sizeof(struct in_addr)]; 168 }; 169 170 void save_rte(struct mbuf *, u_char *, struct in_addr); 171 172 /* 173 * IP initialization: fill in IP protocol switch table. 174 * All protocols not implemented in kernel go to raw IP protocol handler. 175 */ 176 void 177 ip_init(void) 178 { 179 const struct protosw *pr; 180 int i; 181 const u_int16_t defbaddynamicports_tcp[] = DEFBADDYNAMICPORTS_TCP; 182 const u_int16_t defbaddynamicports_udp[] = DEFBADDYNAMICPORTS_UDP; 183 const u_int16_t defrootonlyports_tcp[] = DEFROOTONLYPORTS_TCP; 184 const u_int16_t defrootonlyports_udp[] = DEFROOTONLYPORTS_UDP; 185 186 ipcounters = counters_alloc(ips_ncounters); 187 188 pool_init(&ipqent_pool, sizeof(struct ipqent), 0, 189 IPL_SOFTNET, 0, "ipqe", NULL); 190 pool_init(&ipq_pool, sizeof(struct ipq), 0, 191 IPL_SOFTNET, 0, "ipq", NULL); 192 193 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 194 if (pr == NULL) 195 panic("ip_init"); 196 for (i = 0; i < IPPROTO_MAX; i++) 197 ip_protox[i] = pr - inetsw; 198 for (pr = inetdomain.dom_protosw; 199 pr < inetdomain.dom_protoswNPROTOSW; pr++) 200 if (pr->pr_domain->dom_family == PF_INET && 201 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW && 202 pr->pr_protocol < IPPROTO_MAX) 203 ip_protox[pr->pr_protocol] = pr - inetsw; 204 LIST_INIT(&ipq); 205 206 /* Fill in list of ports not to allocate dynamically. */ 207 memset(&baddynamicports, 0, sizeof(baddynamicports)); 208 for (i = 0; defbaddynamicports_tcp[i] != 0; i++) 209 DP_SET(baddynamicports.tcp, defbaddynamicports_tcp[i]); 210 for (i = 0; defbaddynamicports_udp[i] != 0; i++) 211 DP_SET(baddynamicports.udp, defbaddynamicports_udp[i]); 212 213 /* Fill in list of ports only root can bind to. */ 214 memset(&rootonlyports, 0, sizeof(rootonlyports)); 215 for (i = 0; defrootonlyports_tcp[i] != 0; i++) 216 DP_SET(rootonlyports.tcp, defrootonlyports_tcp[i]); 217 for (i = 0; defrootonlyports_udp[i] != 0; i++) 218 DP_SET(rootonlyports.udp, defrootonlyports_udp[i]); 219 220 mq_init(&ipsend_mq, 64, IPL_SOFTNET); 221 mq_init(&ipsendraw_mq, 64, IPL_SOFTNET); 222 223 arpinit(); 224 #ifdef IPSEC 225 ipsec_init(); 226 #endif 227 #ifdef MROUTING 228 rt_timer_queue_init(&ip_mrouterq, MCAST_EXPIRE_FREQUENCY, 229 &mfc_expire_route); 230 #endif 231 } 232 233 /* 234 * Enqueue packet for local delivery. Queuing is used as a boundary 235 * between the network layer (input/forward path) running with 236 * NET_LOCK_SHARED() and the transport layer needing it exclusively. 237 */ 238 int 239 ip_ours(struct mbuf **mp, int *offp, int nxt, int af) 240 { 241 nxt = ip_fragcheck(mp, offp); 242 if (nxt == IPPROTO_DONE) 243 return IPPROTO_DONE; 244 245 /* We are already in a IPv4/IPv6 local deliver loop. */ 246 if (af != AF_UNSPEC) 247 return nxt; 248 249 niq_enqueue(&ipintrq, *mp); 250 *mp = NULL; 251 return IPPROTO_DONE; 252 } 253 254 /* 255 * Dequeue and process locally delivered packets. 256 * This is called with exclusive NET_LOCK(). 257 */ 258 void 259 ipintr(void) 260 { 261 struct mbuf *m; 262 263 while ((m = niq_dequeue(&ipintrq)) != NULL) { 264 struct ip *ip; 265 int off, nxt; 266 267 #ifdef DIAGNOSTIC 268 if ((m->m_flags & M_PKTHDR) == 0) 269 panic("ipintr no HDR"); 270 #endif 271 ip = mtod(m, struct ip *); 272 off = ip->ip_hl << 2; 273 nxt = ip->ip_p; 274 275 nxt = ip_deliver(&m, &off, nxt, AF_INET); 276 KASSERT(nxt == IPPROTO_DONE); 277 } 278 } 279 280 /* 281 * IPv4 input routine. 282 * 283 * Checksum and byte swap header. Process options. Forward or deliver. 284 */ 285 void 286 ipv4_input(struct ifnet *ifp, struct mbuf *m) 287 { 288 int off, nxt; 289 290 off = 0; 291 nxt = ip_input_if(&m, &off, IPPROTO_IPV4, AF_UNSPEC, ifp); 292 KASSERT(nxt == IPPROTO_DONE); 293 } 294 295 struct mbuf * 296 ipv4_check(struct ifnet *ifp, struct mbuf *m) 297 { 298 struct ip *ip; 299 int hlen, len; 300 301 if (m->m_len < sizeof(*ip)) { 302 m = m_pullup(m, sizeof(*ip)); 303 if (m == NULL) { 304 ipstat_inc(ips_toosmall); 305 return (NULL); 306 } 307 } 308 309 ip = mtod(m, struct ip *); 310 if (ip->ip_v != IPVERSION) { 311 ipstat_inc(ips_badvers); 312 goto bad; 313 } 314 315 hlen = ip->ip_hl << 2; 316 if (hlen < sizeof(*ip)) { /* minimum header length */ 317 ipstat_inc(ips_badhlen); 318 goto bad; 319 } 320 if (hlen > m->m_len) { 321 m = m_pullup(m, hlen); 322 if (m == NULL) { 323 ipstat_inc(ips_badhlen); 324 return (NULL); 325 } 326 ip = mtod(m, struct ip *); 327 } 328 329 /* 127/8 must not appear on wire - RFC1122 */ 330 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 331 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 332 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 333 ipstat_inc(ips_badaddr); 334 goto bad; 335 } 336 } 337 338 if (!ISSET(m->m_pkthdr.csum_flags, M_IPV4_CSUM_IN_OK)) { 339 if (ISSET(m->m_pkthdr.csum_flags, M_IPV4_CSUM_IN_BAD)) { 340 ipstat_inc(ips_badsum); 341 goto bad; 342 } 343 344 ipstat_inc(ips_inswcsum); 345 if (in_cksum(m, hlen) != 0) { 346 ipstat_inc(ips_badsum); 347 goto bad; 348 } 349 350 SET(m->m_pkthdr.csum_flags, M_IPV4_CSUM_IN_OK); 351 } 352 353 /* Retrieve the packet length. */ 354 len = ntohs(ip->ip_len); 355 356 /* 357 * Convert fields to host representation. 358 */ 359 if (len < hlen) { 360 ipstat_inc(ips_badlen); 361 goto bad; 362 } 363 364 /* 365 * Check that the amount of data in the buffers 366 * is at least as much as the IP header would have us expect. 367 * Trim mbufs if longer than we expect. 368 * Drop packet if shorter than we expect. 369 */ 370 if (m->m_pkthdr.len < len) { 371 ipstat_inc(ips_tooshort); 372 goto bad; 373 } 374 if (m->m_pkthdr.len > len) { 375 if (m->m_len == m->m_pkthdr.len) { 376 m->m_len = len; 377 m->m_pkthdr.len = len; 378 } else 379 m_adj(m, len - m->m_pkthdr.len); 380 } 381 382 return (m); 383 bad: 384 m_freem(m); 385 return (NULL); 386 } 387 388 int 389 ip_input_if(struct mbuf **mp, int *offp, int nxt, int af, struct ifnet *ifp) 390 { 391 struct mbuf *m; 392 struct rtentry *rt = NULL; 393 struct ip *ip; 394 int hlen; 395 in_addr_t pfrdr = 0; 396 397 KASSERT(*offp == 0); 398 399 ipstat_inc(ips_total); 400 m = *mp = ipv4_check(ifp, *mp); 401 if (m == NULL) 402 goto bad; 403 404 ip = mtod(m, struct ip *); 405 406 #if NCARP > 0 407 if (carp_lsdrop(ifp, m, AF_INET, &ip->ip_src.s_addr, 408 &ip->ip_dst.s_addr, (ip->ip_p == IPPROTO_ICMP ? 0 : 1))) 409 goto bad; 410 #endif 411 412 #if NPF > 0 413 /* 414 * Packet filter 415 */ 416 pfrdr = ip->ip_dst.s_addr; 417 if (pf_test(AF_INET, PF_IN, ifp, mp) != PF_PASS) 418 goto bad; 419 m = *mp; 420 if (m == NULL) 421 goto bad; 422 423 ip = mtod(m, struct ip *); 424 pfrdr = (pfrdr != ip->ip_dst.s_addr); 425 #endif 426 427 hlen = ip->ip_hl << 2; 428 429 /* 430 * Process options and, if not destined for us, 431 * ship it on. ip_dooptions returns 1 when an 432 * error was detected (causing an icmp message 433 * to be sent and the original packet to be freed). 434 */ 435 if (hlen > sizeof (struct ip) && ip_dooptions(m, ifp)) { 436 m = *mp = NULL; 437 goto bad; 438 } 439 440 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 441 ip->ip_dst.s_addr == INADDR_ANY) { 442 nxt = ip_ours(mp, offp, nxt, af); 443 goto out; 444 } 445 446 switch(in_ouraddr(m, ifp, &rt)) { 447 case 2: 448 goto bad; 449 case 1: 450 nxt = ip_ours(mp, offp, nxt, af); 451 goto out; 452 } 453 454 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 455 /* 456 * Make sure M_MCAST is set. It should theoretically 457 * already be there, but let's play safe because upper 458 * layers check for this flag. 459 */ 460 m->m_flags |= M_MCAST; 461 462 #ifdef MROUTING 463 if (ipmforwarding && ip_mrouter[ifp->if_rdomain]) { 464 int error; 465 466 if (m->m_flags & M_EXT) { 467 if ((m = *mp = m_pullup(m, hlen)) == NULL) { 468 ipstat_inc(ips_toosmall); 469 goto bad; 470 } 471 ip = mtod(m, struct ip *); 472 } 473 /* 474 * If we are acting as a multicast router, all 475 * incoming multicast packets are passed to the 476 * kernel-level multicast forwarding function. 477 * The packet is returned (relatively) intact; if 478 * ip_mforward() returns a non-zero value, the packet 479 * must be discarded, else it may be accepted below. 480 * 481 * (The IP ident field is put in the same byte order 482 * as expected when ip_mforward() is called from 483 * ip_output().) 484 */ 485 KERNEL_LOCK(); 486 error = ip_mforward(m, ifp); 487 KERNEL_UNLOCK(); 488 if (error) { 489 ipstat_inc(ips_cantforward); 490 goto bad; 491 } 492 493 /* 494 * The process-level routing daemon needs to receive 495 * all multicast IGMP packets, whether or not this 496 * host belongs to their destination groups. 497 */ 498 if (ip->ip_p == IPPROTO_IGMP) { 499 nxt = ip_ours(mp, offp, nxt, af); 500 goto out; 501 } 502 ipstat_inc(ips_forward); 503 } 504 #endif 505 /* 506 * See if we belong to the destination multicast group on the 507 * arrival interface. 508 */ 509 if (!in_hasmulti(&ip->ip_dst, ifp)) { 510 ipstat_inc(ips_notmember); 511 if (!IN_LOCAL_GROUP(ip->ip_dst.s_addr)) 512 ipstat_inc(ips_cantforward); 513 goto bad; 514 } 515 nxt = ip_ours(mp, offp, nxt, af); 516 goto out; 517 } 518 519 #if NCARP > 0 520 if (ip->ip_p == IPPROTO_ICMP && 521 carp_lsdrop(ifp, m, AF_INET, &ip->ip_src.s_addr, 522 &ip->ip_dst.s_addr, 1)) 523 goto bad; 524 #endif 525 /* 526 * Not for us; forward if possible and desirable. 527 */ 528 if (ipforwarding == 0) { 529 ipstat_inc(ips_cantforward); 530 goto bad; 531 } 532 #ifdef IPSEC 533 if (ipsec_in_use) { 534 int rv; 535 536 rv = ipsec_forward_check(m, hlen, AF_INET); 537 if (rv != 0) { 538 ipstat_inc(ips_cantforward); 539 goto bad; 540 } 541 /* 542 * Fall through, forward packet. Outbound IPsec policy 543 * checking will occur in ip_output(). 544 */ 545 } 546 #endif /* IPSEC */ 547 548 ip_forward(m, ifp, rt, pfrdr); 549 *mp = NULL; 550 return IPPROTO_DONE; 551 bad: 552 nxt = IPPROTO_DONE; 553 m_freemp(mp); 554 out: 555 rtfree(rt); 556 return nxt; 557 } 558 559 int 560 ip_fragcheck(struct mbuf **mp, int *offp) 561 { 562 struct ip *ip; 563 struct ipq *fp; 564 struct ipqent *ipqe; 565 int hlen; 566 uint16_t mff; 567 568 ip = mtod(*mp, struct ip *); 569 hlen = ip->ip_hl << 2; 570 571 /* 572 * If offset or more fragments are set, must reassemble. 573 * Otherwise, nothing need be done. 574 * (We could look in the reassembly queue to see 575 * if the packet was previously fragmented, 576 * but it's not worth the time; just let them time out.) 577 */ 578 if (ISSET(ip->ip_off, htons(IP_OFFMASK | IP_MF))) { 579 if ((*mp)->m_flags & M_EXT) { /* XXX */ 580 if ((*mp = m_pullup(*mp, hlen)) == NULL) { 581 ipstat_inc(ips_toosmall); 582 return IPPROTO_DONE; 583 } 584 ip = mtod(*mp, struct ip *); 585 } 586 587 /* 588 * Adjust ip_len to not reflect header, 589 * set ipqe_mff if more fragments are expected, 590 * convert offset of this to bytes. 591 */ 592 ip->ip_len = htons(ntohs(ip->ip_len) - hlen); 593 mff = ISSET(ip->ip_off, htons(IP_MF)); 594 if (mff) { 595 /* 596 * Make sure that fragments have a data length 597 * that's a non-zero multiple of 8 bytes. 598 */ 599 if (ntohs(ip->ip_len) == 0 || 600 (ntohs(ip->ip_len) & 0x7) != 0) { 601 ipstat_inc(ips_badfrags); 602 m_freemp(mp); 603 return IPPROTO_DONE; 604 } 605 } 606 ip->ip_off = htons(ntohs(ip->ip_off) << 3); 607 608 mtx_enter(&ipq_mutex); 609 610 /* 611 * Look for queue of fragments 612 * of this datagram. 613 */ 614 LIST_FOREACH(fp, &ipq, ipq_q) { 615 if (ip->ip_id == fp->ipq_id && 616 ip->ip_src.s_addr == fp->ipq_src.s_addr && 617 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 618 ip->ip_p == fp->ipq_p) 619 break; 620 } 621 622 /* 623 * If datagram marked as having more fragments 624 * or if this is not the first fragment, 625 * attempt reassembly; if it succeeds, proceed. 626 */ 627 if (mff || ip->ip_off) { 628 ipstat_inc(ips_fragments); 629 if (ip_frags + 1 > ip_maxqueue) { 630 ip_flush(); 631 ipstat_inc(ips_rcvmemdrop); 632 goto bad; 633 } 634 635 ipqe = pool_get(&ipqent_pool, PR_NOWAIT); 636 if (ipqe == NULL) { 637 ipstat_inc(ips_rcvmemdrop); 638 goto bad; 639 } 640 ip_frags++; 641 ipqe->ipqe_mff = mff; 642 ipqe->ipqe_m = *mp; 643 ipqe->ipqe_ip = ip; 644 *mp = ip_reass(ipqe, fp); 645 if (*mp == NULL) 646 goto bad; 647 ipstat_inc(ips_reassembled); 648 ip = mtod(*mp, struct ip *); 649 hlen = ip->ip_hl << 2; 650 ip->ip_len = htons(ntohs(ip->ip_len) + hlen); 651 } else { 652 if (fp != NULL) 653 ip_freef(fp); 654 } 655 656 mtx_leave(&ipq_mutex); 657 } 658 659 *offp = hlen; 660 return ip->ip_p; 661 662 bad: 663 mtx_leave(&ipq_mutex); 664 m_freemp(mp); 665 return IPPROTO_DONE; 666 } 667 668 #ifndef INET6 669 #define IPSTAT_INC(name) ipstat_inc(ips_##name) 670 #else 671 #define IPSTAT_INC(name) (af == AF_INET ? \ 672 ipstat_inc(ips_##name) : ip6stat_inc(ip6s_##name)) 673 #endif 674 675 int 676 ip_deliver(struct mbuf **mp, int *offp, int nxt, int af) 677 { 678 const struct protosw *psw; 679 int naf = af; 680 #ifdef INET6 681 int nest = 0; 682 #endif /* INET6 */ 683 684 NET_ASSERT_LOCKED_EXCLUSIVE(); 685 686 /* 687 * Tell launch routine the next header 688 */ 689 IPSTAT_INC(delivered); 690 691 while (nxt != IPPROTO_DONE) { 692 #ifdef INET6 693 if (af == AF_INET6 && 694 ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) { 695 ip6stat_inc(ip6s_toomanyhdr); 696 goto bad; 697 } 698 #endif /* INET6 */ 699 700 /* 701 * protection against faulty packet - there should be 702 * more sanity checks in header chain processing. 703 */ 704 if ((*mp)->m_pkthdr.len < *offp) { 705 IPSTAT_INC(tooshort); 706 goto bad; 707 } 708 709 #ifdef IPSEC 710 if (ipsec_in_use) { 711 if (ipsec_local_check(*mp, *offp, nxt, af) != 0) { 712 IPSTAT_INC(cantforward); 713 goto bad; 714 } 715 } 716 /* Otherwise, just fall through and deliver the packet */ 717 #endif /* IPSEC */ 718 719 switch (nxt) { 720 case IPPROTO_IPV4: 721 naf = AF_INET; 722 ipstat_inc(ips_delivered); 723 break; 724 #ifdef INET6 725 case IPPROTO_IPV6: 726 naf = AF_INET6; 727 ip6stat_inc(ip6s_delivered); 728 break; 729 #endif /* INET6 */ 730 } 731 switch (af) { 732 case AF_INET: 733 psw = &inetsw[ip_protox[nxt]]; 734 break; 735 #ifdef INET6 736 case AF_INET6: 737 psw = &inet6sw[ip6_protox[nxt]]; 738 break; 739 #endif /* INET6 */ 740 } 741 nxt = (*psw->pr_input)(mp, offp, nxt, af); 742 af = naf; 743 } 744 return nxt; 745 bad: 746 m_freemp(mp); 747 return IPPROTO_DONE; 748 } 749 #undef IPSTAT_INC 750 751 int 752 in_ouraddr(struct mbuf *m, struct ifnet *ifp, struct rtentry **prt) 753 { 754 struct rtentry *rt; 755 struct ip *ip; 756 struct sockaddr_in sin; 757 int match = 0; 758 759 #if NPF > 0 760 switch (pf_ouraddr(m)) { 761 case 0: 762 return (0); 763 case 1: 764 return (1); 765 default: 766 /* pf does not know it */ 767 break; 768 } 769 #endif 770 771 ip = mtod(m, struct ip *); 772 773 memset(&sin, 0, sizeof(sin)); 774 sin.sin_len = sizeof(sin); 775 sin.sin_family = AF_INET; 776 sin.sin_addr = ip->ip_dst; 777 rt = rtalloc_mpath(sintosa(&sin), &ip->ip_src.s_addr, 778 m->m_pkthdr.ph_rtableid); 779 if (rtisvalid(rt)) { 780 if (ISSET(rt->rt_flags, RTF_LOCAL)) 781 match = 1; 782 783 /* 784 * If directedbcast is enabled we only consider it local 785 * if it is received on the interface with that address. 786 */ 787 if (ISSET(rt->rt_flags, RTF_BROADCAST) && 788 (!ip_directedbcast || rt->rt_ifidx == ifp->if_index)) { 789 match = 1; 790 791 /* Make sure M_BCAST is set */ 792 m->m_flags |= M_BCAST; 793 } 794 } 795 *prt = rt; 796 797 if (!match) { 798 struct ifaddr *ifa; 799 800 /* 801 * No local address or broadcast address found, so check for 802 * ancient classful broadcast addresses. 803 * It must have been broadcast on the link layer, and for an 804 * address on the interface it was received on. 805 */ 806 if (!ISSET(m->m_flags, M_BCAST) || 807 !IN_CLASSFULBROADCAST(ip->ip_dst.s_addr, ip->ip_dst.s_addr)) 808 return (0); 809 810 if (ifp->if_rdomain != rtable_l2(m->m_pkthdr.ph_rtableid)) 811 return (0); 812 /* 813 * The check in the loop assumes you only rx a packet on an UP 814 * interface, and that M_BCAST will only be set on a BROADCAST 815 * interface. 816 */ 817 NET_ASSERT_LOCKED(); 818 TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) { 819 if (ifa->ifa_addr->sa_family != AF_INET) 820 continue; 821 822 if (IN_CLASSFULBROADCAST(ip->ip_dst.s_addr, 823 ifatoia(ifa)->ia_addr.sin_addr.s_addr)) { 824 match = 1; 825 break; 826 } 827 } 828 } else if (ipforwarding == 0 && rt->rt_ifidx != ifp->if_index && 829 !((ifp->if_flags & IFF_LOOPBACK) || (ifp->if_type == IFT_ENC) || 830 (m->m_pkthdr.pf.flags & PF_TAG_TRANSLATE_LOCALHOST))) { 831 /* received on wrong interface. */ 832 #if NCARP > 0 833 struct ifnet *out_if; 834 835 /* 836 * Virtual IPs on carp interfaces need to be checked also 837 * against the parent interface and other carp interfaces 838 * sharing the same parent. 839 */ 840 out_if = if_get(rt->rt_ifidx); 841 if (!(out_if && carp_strict_addr_chk(out_if, ifp))) { 842 ipstat_inc(ips_wrongif); 843 match = 2; 844 } 845 if_put(out_if); 846 #else 847 ipstat_inc(ips_wrongif); 848 match = 2; 849 #endif 850 } 851 852 return (match); 853 } 854 855 /* 856 * Take incoming datagram fragment and try to 857 * reassemble it into whole datagram. If a chain for 858 * reassembly of this datagram already exists, then it 859 * is given as fp; otherwise have to make a chain. 860 */ 861 struct mbuf * 862 ip_reass(struct ipqent *ipqe, struct ipq *fp) 863 { 864 struct mbuf *m = ipqe->ipqe_m; 865 struct ipqent *nq, *p, *q; 866 struct ip *ip; 867 struct mbuf *t; 868 int hlen = ipqe->ipqe_ip->ip_hl << 2; 869 int i, next; 870 u_int8_t ecn, ecn0; 871 872 MUTEX_ASSERT_LOCKED(&ipq_mutex); 873 874 /* 875 * Presence of header sizes in mbufs 876 * would confuse code below. 877 */ 878 m->m_data += hlen; 879 m->m_len -= hlen; 880 881 /* 882 * If first fragment to arrive, create a reassembly queue. 883 */ 884 if (fp == NULL) { 885 fp = pool_get(&ipq_pool, PR_NOWAIT); 886 if (fp == NULL) 887 goto dropfrag; 888 LIST_INSERT_HEAD(&ipq, fp, ipq_q); 889 fp->ipq_ttl = IPFRAGTTL; 890 fp->ipq_p = ipqe->ipqe_ip->ip_p; 891 fp->ipq_id = ipqe->ipqe_ip->ip_id; 892 LIST_INIT(&fp->ipq_fragq); 893 fp->ipq_src = ipqe->ipqe_ip->ip_src; 894 fp->ipq_dst = ipqe->ipqe_ip->ip_dst; 895 p = NULL; 896 goto insert; 897 } 898 899 /* 900 * Handle ECN by comparing this segment with the first one; 901 * if CE is set, do not lose CE. 902 * drop if CE and not-ECT are mixed for the same packet. 903 */ 904 ecn = ipqe->ipqe_ip->ip_tos & IPTOS_ECN_MASK; 905 ecn0 = LIST_FIRST(&fp->ipq_fragq)->ipqe_ip->ip_tos & IPTOS_ECN_MASK; 906 if (ecn == IPTOS_ECN_CE) { 907 if (ecn0 == IPTOS_ECN_NOTECT) 908 goto dropfrag; 909 if (ecn0 != IPTOS_ECN_CE) 910 LIST_FIRST(&fp->ipq_fragq)->ipqe_ip->ip_tos |= 911 IPTOS_ECN_CE; 912 } 913 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 914 goto dropfrag; 915 916 /* 917 * Find a segment which begins after this one does. 918 */ 919 for (p = NULL, q = LIST_FIRST(&fp->ipq_fragq); q != NULL; 920 p = q, q = LIST_NEXT(q, ipqe_q)) 921 if (ntohs(q->ipqe_ip->ip_off) > ntohs(ipqe->ipqe_ip->ip_off)) 922 break; 923 924 /* 925 * If there is a preceding segment, it may provide some of 926 * our data already. If so, drop the data from the incoming 927 * segment. If it provides all of our data, drop us. 928 */ 929 if (p != NULL) { 930 i = ntohs(p->ipqe_ip->ip_off) + ntohs(p->ipqe_ip->ip_len) - 931 ntohs(ipqe->ipqe_ip->ip_off); 932 if (i > 0) { 933 if (i >= ntohs(ipqe->ipqe_ip->ip_len)) 934 goto dropfrag; 935 m_adj(ipqe->ipqe_m, i); 936 ipqe->ipqe_ip->ip_off = 937 htons(ntohs(ipqe->ipqe_ip->ip_off) + i); 938 ipqe->ipqe_ip->ip_len = 939 htons(ntohs(ipqe->ipqe_ip->ip_len) - i); 940 } 941 } 942 943 /* 944 * While we overlap succeeding segments trim them or, 945 * if they are completely covered, dequeue them. 946 */ 947 for (; q != NULL && 948 ntohs(ipqe->ipqe_ip->ip_off) + ntohs(ipqe->ipqe_ip->ip_len) > 949 ntohs(q->ipqe_ip->ip_off); q = nq) { 950 i = (ntohs(ipqe->ipqe_ip->ip_off) + 951 ntohs(ipqe->ipqe_ip->ip_len)) - ntohs(q->ipqe_ip->ip_off); 952 if (i < ntohs(q->ipqe_ip->ip_len)) { 953 q->ipqe_ip->ip_len = 954 htons(ntohs(q->ipqe_ip->ip_len) - i); 955 q->ipqe_ip->ip_off = 956 htons(ntohs(q->ipqe_ip->ip_off) + i); 957 m_adj(q->ipqe_m, i); 958 break; 959 } 960 nq = LIST_NEXT(q, ipqe_q); 961 m_freem(q->ipqe_m); 962 LIST_REMOVE(q, ipqe_q); 963 pool_put(&ipqent_pool, q); 964 ip_frags--; 965 } 966 967 insert: 968 /* 969 * Stick new segment in its place; 970 * check for complete reassembly. 971 */ 972 if (p == NULL) { 973 LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); 974 } else { 975 LIST_INSERT_AFTER(p, ipqe, ipqe_q); 976 } 977 next = 0; 978 for (p = NULL, q = LIST_FIRST(&fp->ipq_fragq); q != NULL; 979 p = q, q = LIST_NEXT(q, ipqe_q)) { 980 if (ntohs(q->ipqe_ip->ip_off) != next) 981 return (0); 982 next += ntohs(q->ipqe_ip->ip_len); 983 } 984 if (p->ipqe_mff) 985 return (0); 986 987 /* 988 * Reassembly is complete. Check for a bogus message size and 989 * concatenate fragments. 990 */ 991 q = LIST_FIRST(&fp->ipq_fragq); 992 ip = q->ipqe_ip; 993 if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) { 994 ipstat_inc(ips_toolong); 995 ip_freef(fp); 996 return (0); 997 } 998 m = q->ipqe_m; 999 t = m->m_next; 1000 m->m_next = 0; 1001 m_cat(m, t); 1002 nq = LIST_NEXT(q, ipqe_q); 1003 pool_put(&ipqent_pool, q); 1004 ip_frags--; 1005 for (q = nq; q != NULL; q = nq) { 1006 t = q->ipqe_m; 1007 nq = LIST_NEXT(q, ipqe_q); 1008 pool_put(&ipqent_pool, q); 1009 ip_frags--; 1010 m_removehdr(t); 1011 m_cat(m, t); 1012 } 1013 1014 /* 1015 * Create header for new ip packet by 1016 * modifying header of first packet; 1017 * dequeue and discard fragment reassembly header. 1018 * Make header visible. 1019 */ 1020 ip->ip_len = htons(next); 1021 ip->ip_src = fp->ipq_src; 1022 ip->ip_dst = fp->ipq_dst; 1023 LIST_REMOVE(fp, ipq_q); 1024 pool_put(&ipq_pool, fp); 1025 m->m_len += (ip->ip_hl << 2); 1026 m->m_data -= (ip->ip_hl << 2); 1027 m_calchdrlen(m); 1028 return (m); 1029 1030 dropfrag: 1031 ipstat_inc(ips_fragdropped); 1032 m_freem(m); 1033 pool_put(&ipqent_pool, ipqe); 1034 ip_frags--; 1035 return (NULL); 1036 } 1037 1038 /* 1039 * Free a fragment reassembly header and all 1040 * associated datagrams. 1041 */ 1042 void 1043 ip_freef(struct ipq *fp) 1044 { 1045 struct ipqent *q; 1046 1047 MUTEX_ASSERT_LOCKED(&ipq_mutex); 1048 1049 while ((q = LIST_FIRST(&fp->ipq_fragq)) != NULL) { 1050 LIST_REMOVE(q, ipqe_q); 1051 m_freem(q->ipqe_m); 1052 pool_put(&ipqent_pool, q); 1053 ip_frags--; 1054 } 1055 LIST_REMOVE(fp, ipq_q); 1056 pool_put(&ipq_pool, fp); 1057 } 1058 1059 /* 1060 * IP timer processing; 1061 * if a timer expires on a reassembly queue, discard it. 1062 */ 1063 void 1064 ip_slowtimo(void) 1065 { 1066 struct ipq *fp, *nfp; 1067 1068 mtx_enter(&ipq_mutex); 1069 LIST_FOREACH_SAFE(fp, &ipq, ipq_q, nfp) { 1070 if (--fp->ipq_ttl == 0) { 1071 ipstat_inc(ips_fragtimeout); 1072 ip_freef(fp); 1073 } 1074 } 1075 mtx_leave(&ipq_mutex); 1076 } 1077 1078 /* 1079 * Flush a bunch of datagram fragments, till we are down to 75%. 1080 */ 1081 void 1082 ip_flush(void) 1083 { 1084 int max = 50; 1085 1086 MUTEX_ASSERT_LOCKED(&ipq_mutex); 1087 1088 while (!LIST_EMPTY(&ipq) && ip_frags > ip_maxqueue * 3 / 4 && --max) { 1089 ipstat_inc(ips_fragdropped); 1090 ip_freef(LIST_FIRST(&ipq)); 1091 } 1092 } 1093 1094 /* 1095 * Do option processing on a datagram, 1096 * possibly discarding it if bad options are encountered, 1097 * or forwarding it if source-routed. 1098 * Returns 1 if packet has been forwarded/freed, 1099 * 0 if the packet should be processed further. 1100 */ 1101 int 1102 ip_dooptions(struct mbuf *m, struct ifnet *ifp) 1103 { 1104 struct ip *ip = mtod(m, struct ip *); 1105 unsigned int rtableid = m->m_pkthdr.ph_rtableid; 1106 struct rtentry *rt; 1107 struct sockaddr_in ipaddr; 1108 u_char *cp; 1109 struct ip_timestamp ipt; 1110 struct in_ifaddr *ia; 1111 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1112 struct in_addr sin, dst; 1113 u_int32_t ntime; 1114 1115 dst = ip->ip_dst; 1116 cp = (u_char *)(ip + 1); 1117 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1118 1119 KERNEL_LOCK(); 1120 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1121 opt = cp[IPOPT_OPTVAL]; 1122 if (opt == IPOPT_EOL) 1123 break; 1124 if (opt == IPOPT_NOP) 1125 optlen = 1; 1126 else { 1127 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1128 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1129 goto bad; 1130 } 1131 optlen = cp[IPOPT_OLEN]; 1132 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1133 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1134 goto bad; 1135 } 1136 } 1137 1138 switch (opt) { 1139 1140 default: 1141 break; 1142 1143 /* 1144 * Source routing with record. 1145 * Find interface with current destination address. 1146 * If none on this machine then drop if strictly routed, 1147 * or do nothing if loosely routed. 1148 * Record interface address and bring up next address 1149 * component. If strictly routed make sure next 1150 * address is on directly accessible net. 1151 */ 1152 case IPOPT_LSRR: 1153 case IPOPT_SSRR: 1154 if (!ip_dosourceroute) { 1155 type = ICMP_UNREACH; 1156 code = ICMP_UNREACH_SRCFAIL; 1157 goto bad; 1158 } 1159 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1160 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1161 goto bad; 1162 } 1163 memset(&ipaddr, 0, sizeof(ipaddr)); 1164 ipaddr.sin_family = AF_INET; 1165 ipaddr.sin_len = sizeof(ipaddr); 1166 ipaddr.sin_addr = ip->ip_dst; 1167 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr), 1168 m->m_pkthdr.ph_rtableid)); 1169 if (ia == NULL) { 1170 if (opt == IPOPT_SSRR) { 1171 type = ICMP_UNREACH; 1172 code = ICMP_UNREACH_SRCFAIL; 1173 goto bad; 1174 } 1175 /* 1176 * Loose routing, and not at next destination 1177 * yet; nothing to do except forward. 1178 */ 1179 break; 1180 } 1181 off--; /* 0 origin */ 1182 if ((off + sizeof(struct in_addr)) > optlen) { 1183 /* 1184 * End of source route. Should be for us. 1185 */ 1186 save_rte(m, cp, ip->ip_src); 1187 break; 1188 } 1189 1190 /* 1191 * locate outgoing interface 1192 */ 1193 memset(&ipaddr, 0, sizeof(ipaddr)); 1194 ipaddr.sin_family = AF_INET; 1195 ipaddr.sin_len = sizeof(ipaddr); 1196 memcpy(&ipaddr.sin_addr, cp + off, 1197 sizeof(ipaddr.sin_addr)); 1198 /* keep packet in the virtual instance */ 1199 rt = rtalloc(sintosa(&ipaddr), RT_RESOLVE, rtableid); 1200 if (!rtisvalid(rt) || ((opt == IPOPT_SSRR) && 1201 ISSET(rt->rt_flags, RTF_GATEWAY))) { 1202 type = ICMP_UNREACH; 1203 code = ICMP_UNREACH_SRCFAIL; 1204 rtfree(rt); 1205 goto bad; 1206 } 1207 ia = ifatoia(rt->rt_ifa); 1208 memcpy(cp + off, &ia->ia_addr.sin_addr, 1209 sizeof(struct in_addr)); 1210 rtfree(rt); 1211 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1212 ip->ip_dst = ipaddr.sin_addr; 1213 /* 1214 * Let ip_intr's mcast routing check handle mcast pkts 1215 */ 1216 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1217 break; 1218 1219 case IPOPT_RR: 1220 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1221 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1222 goto bad; 1223 } 1224 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1225 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1226 goto bad; 1227 } 1228 1229 /* 1230 * If no space remains, ignore. 1231 */ 1232 off--; /* 0 origin */ 1233 if ((off + sizeof(struct in_addr)) > optlen) 1234 break; 1235 memset(&ipaddr, 0, sizeof(ipaddr)); 1236 ipaddr.sin_family = AF_INET; 1237 ipaddr.sin_len = sizeof(ipaddr); 1238 ipaddr.sin_addr = ip->ip_dst; 1239 /* 1240 * locate outgoing interface; if we're the destination, 1241 * use the incoming interface (should be same). 1242 * Again keep the packet inside the virtual instance. 1243 */ 1244 rt = rtalloc(sintosa(&ipaddr), RT_RESOLVE, rtableid); 1245 if (!rtisvalid(rt)) { 1246 type = ICMP_UNREACH; 1247 code = ICMP_UNREACH_HOST; 1248 rtfree(rt); 1249 goto bad; 1250 } 1251 ia = ifatoia(rt->rt_ifa); 1252 memcpy(cp + off, &ia->ia_addr.sin_addr, 1253 sizeof(struct in_addr)); 1254 rtfree(rt); 1255 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1256 break; 1257 1258 case IPOPT_TS: 1259 code = cp - (u_char *)ip; 1260 if (optlen < sizeof(struct ip_timestamp)) 1261 goto bad; 1262 memcpy(&ipt, cp, sizeof(struct ip_timestamp)); 1263 if (ipt.ipt_ptr < 5 || ipt.ipt_len < 5) 1264 goto bad; 1265 if (ipt.ipt_ptr - 1 + sizeof(u_int32_t) > ipt.ipt_len) { 1266 if (++ipt.ipt_oflw == 0) 1267 goto bad; 1268 break; 1269 } 1270 memcpy(&sin, cp + ipt.ipt_ptr - 1, sizeof sin); 1271 switch (ipt.ipt_flg) { 1272 1273 case IPOPT_TS_TSONLY: 1274 break; 1275 1276 case IPOPT_TS_TSANDADDR: 1277 if (ipt.ipt_ptr - 1 + sizeof(u_int32_t) + 1278 sizeof(struct in_addr) > ipt.ipt_len) 1279 goto bad; 1280 memset(&ipaddr, 0, sizeof(ipaddr)); 1281 ipaddr.sin_family = AF_INET; 1282 ipaddr.sin_len = sizeof(ipaddr); 1283 ipaddr.sin_addr = dst; 1284 ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr), 1285 ifp)); 1286 if (ia == NULL) 1287 continue; 1288 memcpy(&sin, &ia->ia_addr.sin_addr, 1289 sizeof(struct in_addr)); 1290 ipt.ipt_ptr += sizeof(struct in_addr); 1291 break; 1292 1293 case IPOPT_TS_PRESPEC: 1294 if (ipt.ipt_ptr - 1 + sizeof(u_int32_t) + 1295 sizeof(struct in_addr) > ipt.ipt_len) 1296 goto bad; 1297 memset(&ipaddr, 0, sizeof(ipaddr)); 1298 ipaddr.sin_family = AF_INET; 1299 ipaddr.sin_len = sizeof(ipaddr); 1300 ipaddr.sin_addr = sin; 1301 if (ifa_ifwithaddr(sintosa(&ipaddr), 1302 m->m_pkthdr.ph_rtableid) == NULL) 1303 continue; 1304 ipt.ipt_ptr += sizeof(struct in_addr); 1305 break; 1306 1307 default: 1308 /* XXX can't take &ipt->ipt_flg */ 1309 code = (u_char *)&ipt.ipt_ptr - 1310 (u_char *)ip + 1; 1311 goto bad; 1312 } 1313 ntime = iptime(); 1314 memcpy(cp + ipt.ipt_ptr - 1, &ntime, sizeof(u_int32_t)); 1315 ipt.ipt_ptr += sizeof(u_int32_t); 1316 } 1317 } 1318 KERNEL_UNLOCK(); 1319 if (forward && ipforwarding > 0) { 1320 ip_forward(m, ifp, NULL, 1); 1321 return (1); 1322 } 1323 return (0); 1324 bad: 1325 KERNEL_UNLOCK(); 1326 icmp_error(m, type, code, 0, 0); 1327 ipstat_inc(ips_badoptions); 1328 return (1); 1329 } 1330 1331 /* 1332 * Save incoming source route for use in replies, 1333 * to be picked up later by ip_srcroute if the receiver is interested. 1334 */ 1335 void 1336 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1337 { 1338 struct ip_srcrt *isr; 1339 struct m_tag *mtag; 1340 unsigned olen; 1341 1342 olen = option[IPOPT_OLEN]; 1343 if (olen > sizeof(isr->isr_hdr) + sizeof(isr->isr_routes)) 1344 return; 1345 1346 mtag = m_tag_get(PACKET_TAG_SRCROUTE, sizeof(*isr), M_NOWAIT); 1347 if (mtag == NULL) { 1348 ipstat_inc(ips_idropped); 1349 return; 1350 } 1351 isr = (struct ip_srcrt *)(mtag + 1); 1352 1353 memcpy(isr->isr_hdr, option, olen); 1354 isr->isr_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1355 isr->isr_dst = dst; 1356 m_tag_prepend(m, mtag); 1357 } 1358 1359 /* 1360 * Retrieve incoming source route for use in replies, 1361 * in the same form used by setsockopt. 1362 * The first hop is placed before the options, will be removed later. 1363 */ 1364 struct mbuf * 1365 ip_srcroute(struct mbuf *m0) 1366 { 1367 struct in_addr *p, *q; 1368 struct mbuf *m; 1369 struct ip_srcrt *isr; 1370 struct m_tag *mtag; 1371 1372 if (!ip_dosourceroute) 1373 return (NULL); 1374 1375 mtag = m_tag_find(m0, PACKET_TAG_SRCROUTE, NULL); 1376 if (mtag == NULL) 1377 return (NULL); 1378 isr = (struct ip_srcrt *)(mtag + 1); 1379 1380 if (isr->isr_nhops == 0) 1381 return (NULL); 1382 m = m_get(M_DONTWAIT, MT_SOOPTS); 1383 if (m == NULL) { 1384 ipstat_inc(ips_idropped); 1385 return (NULL); 1386 } 1387 1388 #define OPTSIZ (sizeof(isr->isr_nop) + sizeof(isr->isr_hdr)) 1389 1390 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + header) */ 1391 m->m_len = (isr->isr_nhops + 1) * sizeof(struct in_addr) + OPTSIZ; 1392 1393 /* 1394 * First save first hop for return route 1395 */ 1396 p = &(isr->isr_routes[isr->isr_nhops - 1]); 1397 *(mtod(m, struct in_addr *)) = *p--; 1398 1399 /* 1400 * Copy option fields and padding (nop) to mbuf. 1401 */ 1402 isr->isr_nop = IPOPT_NOP; 1403 isr->isr_hdr[IPOPT_OFFSET] = IPOPT_MINOFF; 1404 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &isr->isr_nop, 1405 OPTSIZ); 1406 q = (struct in_addr *)(mtod(m, caddr_t) + 1407 sizeof(struct in_addr) + OPTSIZ); 1408 #undef OPTSIZ 1409 /* 1410 * Record return path as an IP source route, 1411 * reversing the path (pointers are now aligned). 1412 */ 1413 while (p >= isr->isr_routes) { 1414 *q++ = *p--; 1415 } 1416 /* 1417 * Last hop goes to final destination. 1418 */ 1419 *q = isr->isr_dst; 1420 m_tag_delete(m0, (struct m_tag *)isr); 1421 return (m); 1422 } 1423 1424 /* 1425 * Strip out IP options, at higher level protocol in the kernel. 1426 */ 1427 void 1428 ip_stripoptions(struct mbuf *m) 1429 { 1430 int i; 1431 struct ip *ip = mtod(m, struct ip *); 1432 caddr_t opts; 1433 int olen; 1434 1435 olen = (ip->ip_hl<<2) - sizeof (struct ip); 1436 opts = (caddr_t)(ip + 1); 1437 i = m->m_len - (sizeof (struct ip) + olen); 1438 memmove(opts, opts + olen, i); 1439 m->m_len -= olen; 1440 if (m->m_flags & M_PKTHDR) 1441 m->m_pkthdr.len -= olen; 1442 ip->ip_hl = sizeof(struct ip) >> 2; 1443 ip->ip_len = htons(ntohs(ip->ip_len) - olen); 1444 } 1445 1446 const u_char inetctlerrmap[PRC_NCMDS] = { 1447 0, 0, 0, 0, 1448 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1449 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1450 EMSGSIZE, EHOSTUNREACH, 0, 0, 1451 0, 0, 0, 0, 1452 ENOPROTOOPT 1453 }; 1454 1455 /* 1456 * Forward a packet. If some error occurs return the sender 1457 * an icmp packet. Note we can't always generate a meaningful 1458 * icmp message because icmp doesn't have a large enough repertoire 1459 * of codes and types. 1460 * 1461 * If not forwarding, just drop the packet. This could be confusing 1462 * if ipforwarding was zero but some routing protocol was advancing 1463 * us as a gateway to somewhere. However, we must let the routing 1464 * protocol deal with that. 1465 * 1466 * The srcrt parameter indicates whether the packet is being forwarded 1467 * via a source route. 1468 */ 1469 void 1470 ip_forward(struct mbuf *m, struct ifnet *ifp, struct rtentry *rt, int srcrt) 1471 { 1472 struct mbuf mfake, *mcopy = NULL; 1473 struct ip *ip = mtod(m, struct ip *); 1474 struct sockaddr_in *sin; 1475 struct route ro; 1476 int error = 0, type = 0, code = 0, destmtu = 0, fake = 0, len; 1477 u_int32_t dest; 1478 1479 dest = 0; 1480 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1481 ipstat_inc(ips_cantforward); 1482 m_freem(m); 1483 goto freecopy; 1484 } 1485 if (ip->ip_ttl <= IPTTLDEC) { 1486 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1487 goto freecopy; 1488 } 1489 1490 memset(&ro, 0, sizeof(ro)); 1491 sin = satosin(&ro.ro_dst); 1492 sin->sin_family = AF_INET; 1493 sin->sin_len = sizeof(*sin); 1494 sin->sin_addr = ip->ip_dst; 1495 1496 if (!rtisvalid(rt)) { 1497 rtfree(rt); 1498 rt = rtalloc_mpath(sintosa(sin), &ip->ip_src.s_addr, 1499 m->m_pkthdr.ph_rtableid); 1500 if (rt == NULL) { 1501 ipstat_inc(ips_noroute); 1502 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1503 return; 1504 } 1505 } 1506 1507 /* 1508 * Save at most 68 bytes of the packet in case 1509 * we need to generate an ICMP message to the src. 1510 * The data is saved in the mbuf on the stack that 1511 * acts as a temporary storage not intended to be 1512 * passed down the IP stack or to the mfree. 1513 */ 1514 memset(&mfake.m_hdr, 0, sizeof(mfake.m_hdr)); 1515 mfake.m_type = m->m_type; 1516 if (m_dup_pkthdr(&mfake, m, M_DONTWAIT) == 0) { 1517 mfake.m_data = mfake.m_pktdat; 1518 len = min(ntohs(ip->ip_len), 68); 1519 m_copydata(m, 0, len, mfake.m_pktdat); 1520 mfake.m_pkthdr.len = mfake.m_len = len; 1521 #if NPF > 0 1522 pf_pkt_addr_changed(&mfake); 1523 #endif /* NPF > 0 */ 1524 fake = 1; 1525 } 1526 1527 ip->ip_ttl -= IPTTLDEC; 1528 1529 /* 1530 * If forwarding packet using same interface that it came in on, 1531 * perhaps should send a redirect to sender to shortcut a hop. 1532 * Only send redirect if source is sending directly to us, 1533 * and if packet was not source routed (or has any options). 1534 * Also, don't send redirect if forwarding using a default route 1535 * or a route modified by a redirect. 1536 * Don't send redirect if we advertise destination's arp address 1537 * as ours (proxy arp). 1538 */ 1539 if ((rt->rt_ifidx == ifp->if_index) && 1540 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1541 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1542 ipsendredirects && !srcrt && 1543 !arpproxy(satosin(rt_key(rt))->sin_addr, m->m_pkthdr.ph_rtableid)) { 1544 if ((ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_netmask) == 1545 ifatoia(rt->rt_ifa)->ia_net) { 1546 if (rt->rt_flags & RTF_GATEWAY) 1547 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1548 else 1549 dest = ip->ip_dst.s_addr; 1550 /* Router requirements says to only send host redirects */ 1551 type = ICMP_REDIRECT; 1552 code = ICMP_REDIRECT_HOST; 1553 } 1554 } 1555 1556 ro.ro_rt = rt; 1557 ro.ro_tableid = m->m_pkthdr.ph_rtableid; 1558 error = ip_output(m, NULL, &ro, 1559 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1560 NULL, NULL, 0); 1561 rt = ro.ro_rt; 1562 if (error) 1563 ipstat_inc(ips_cantforward); 1564 else { 1565 ipstat_inc(ips_forward); 1566 if (type) 1567 ipstat_inc(ips_redirectsent); 1568 else 1569 goto freecopy; 1570 } 1571 if (!fake) 1572 goto freecopy; 1573 1574 switch (error) { 1575 case 0: /* forwarded, but need redirect */ 1576 /* type, code set above */ 1577 break; 1578 1579 case EMSGSIZE: 1580 type = ICMP_UNREACH; 1581 code = ICMP_UNREACH_NEEDFRAG; 1582 if (rt != NULL) { 1583 if (rt->rt_mtu) { 1584 destmtu = rt->rt_mtu; 1585 } else { 1586 struct ifnet *destifp; 1587 1588 destifp = if_get(rt->rt_ifidx); 1589 if (destifp != NULL) 1590 destmtu = destifp->if_mtu; 1591 if_put(destifp); 1592 } 1593 } 1594 ipstat_inc(ips_cantfrag); 1595 if (destmtu == 0) 1596 goto freecopy; 1597 break; 1598 1599 case EACCES: 1600 /* 1601 * pf(4) blocked the packet. There is no need to send an ICMP 1602 * packet back since pf(4) takes care of it. 1603 */ 1604 goto freecopy; 1605 1606 case ENOBUFS: 1607 /* 1608 * a router should not generate ICMP_SOURCEQUENCH as 1609 * required in RFC1812 Requirements for IP Version 4 Routers. 1610 * source quench could be a big problem under DoS attacks, 1611 * or the underlying interface is rate-limited. 1612 */ 1613 goto freecopy; 1614 1615 case ENETUNREACH: /* shouldn't happen, checked above */ 1616 case EHOSTUNREACH: 1617 case ENETDOWN: 1618 case EHOSTDOWN: 1619 default: 1620 type = ICMP_UNREACH; 1621 code = ICMP_UNREACH_HOST; 1622 break; 1623 } 1624 mcopy = m_copym(&mfake, 0, len, M_DONTWAIT); 1625 if (mcopy) 1626 icmp_error(mcopy, type, code, dest, destmtu); 1627 1628 freecopy: 1629 if (fake) 1630 m_tag_delete_chain(&mfake); 1631 rtfree(rt); 1632 } 1633 1634 int 1635 ip_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp, 1636 size_t newlen) 1637 { 1638 int error; 1639 #ifdef MROUTING 1640 extern struct mrtstat mrtstat; 1641 #endif 1642 1643 /* Almost all sysctl names at this level are terminal. */ 1644 if (namelen != 1 && name[0] != IPCTL_IFQUEUE && 1645 name[0] != IPCTL_ARPQUEUE) 1646 return (ENOTDIR); 1647 1648 switch (name[0]) { 1649 case IPCTL_SOURCEROUTE: 1650 NET_LOCK(); 1651 error = sysctl_securelevel_int(oldp, oldlenp, newp, newlen, 1652 &ip_dosourceroute); 1653 NET_UNLOCK(); 1654 return (error); 1655 case IPCTL_MTUDISC: 1656 NET_LOCK(); 1657 error = sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtudisc); 1658 if (ip_mtudisc == 0) 1659 rt_timer_queue_flush(&ip_mtudisc_timeout_q); 1660 NET_UNLOCK(); 1661 return error; 1662 case IPCTL_MTUDISCTIMEOUT: 1663 NET_LOCK(); 1664 error = sysctl_int_bounded(oldp, oldlenp, newp, newlen, 1665 &ip_mtudisc_timeout, 0, INT_MAX); 1666 rt_timer_queue_change(&ip_mtudisc_timeout_q, 1667 ip_mtudisc_timeout); 1668 NET_UNLOCK(); 1669 return (error); 1670 #ifdef IPSEC 1671 case IPCTL_ENCDEBUG: 1672 case IPCTL_IPSEC_STATS: 1673 case IPCTL_IPSEC_EXPIRE_ACQUIRE: 1674 case IPCTL_IPSEC_EMBRYONIC_SA_TIMEOUT: 1675 case IPCTL_IPSEC_REQUIRE_PFS: 1676 case IPCTL_IPSEC_SOFT_ALLOCATIONS: 1677 case IPCTL_IPSEC_ALLOCATIONS: 1678 case IPCTL_IPSEC_SOFT_BYTES: 1679 case IPCTL_IPSEC_BYTES: 1680 case IPCTL_IPSEC_TIMEOUT: 1681 case IPCTL_IPSEC_SOFT_TIMEOUT: 1682 case IPCTL_IPSEC_SOFT_FIRSTUSE: 1683 case IPCTL_IPSEC_FIRSTUSE: 1684 case IPCTL_IPSEC_ENC_ALGORITHM: 1685 case IPCTL_IPSEC_AUTH_ALGORITHM: 1686 case IPCTL_IPSEC_IPCOMP_ALGORITHM: 1687 return (ipsec_sysctl(name, namelen, oldp, oldlenp, newp, 1688 newlen)); 1689 #endif 1690 case IPCTL_IFQUEUE: 1691 return (sysctl_niq(name + 1, namelen - 1, 1692 oldp, oldlenp, newp, newlen, &ipintrq)); 1693 case IPCTL_ARPQUEUE: 1694 return (sysctl_niq(name + 1, namelen - 1, 1695 oldp, oldlenp, newp, newlen, &arpinq)); 1696 case IPCTL_ARPQUEUED: 1697 return (sysctl_rdint(oldp, oldlenp, newp, la_hold_total)); 1698 case IPCTL_STATS: 1699 return (ip_sysctl_ipstat(oldp, oldlenp, newp)); 1700 #ifdef MROUTING 1701 case IPCTL_MRTSTATS: 1702 return (sysctl_rdstruct(oldp, oldlenp, newp, 1703 &mrtstat, sizeof(mrtstat))); 1704 case IPCTL_MRTMFC: 1705 if (newp) 1706 return (EPERM); 1707 NET_LOCK(); 1708 error = mrt_sysctl_mfc(oldp, oldlenp); 1709 NET_UNLOCK(); 1710 return (error); 1711 case IPCTL_MRTVIF: 1712 if (newp) 1713 return (EPERM); 1714 NET_LOCK(); 1715 error = mrt_sysctl_vif(oldp, oldlenp); 1716 NET_UNLOCK(); 1717 return (error); 1718 #else 1719 case IPCTL_MRTPROTO: 1720 case IPCTL_MRTSTATS: 1721 case IPCTL_MRTMFC: 1722 case IPCTL_MRTVIF: 1723 return (EOPNOTSUPP); 1724 #endif 1725 default: 1726 NET_LOCK(); 1727 error = sysctl_bounded_arr(ipctl_vars, nitems(ipctl_vars), 1728 name, namelen, oldp, oldlenp, newp, newlen); 1729 NET_UNLOCK(); 1730 return (error); 1731 } 1732 /* NOTREACHED */ 1733 } 1734 1735 int 1736 ip_sysctl_ipstat(void *oldp, size_t *oldlenp, void *newp) 1737 { 1738 uint64_t counters[ips_ncounters]; 1739 struct ipstat ipstat; 1740 u_long *words = (u_long *)&ipstat; 1741 int i; 1742 1743 CTASSERT(sizeof(ipstat) == (nitems(counters) * sizeof(u_long))); 1744 memset(&ipstat, 0, sizeof ipstat); 1745 counters_read(ipcounters, counters, nitems(counters)); 1746 1747 for (i = 0; i < nitems(counters); i++) 1748 words[i] = (u_long)counters[i]; 1749 1750 return (sysctl_rdstruct(oldp, oldlenp, newp, &ipstat, sizeof(ipstat))); 1751 } 1752 1753 void 1754 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1755 struct mbuf *m) 1756 { 1757 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1758 struct timeval tv; 1759 1760 m_microtime(m, &tv); 1761 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1762 SCM_TIMESTAMP, SOL_SOCKET); 1763 if (*mp) 1764 mp = &(*mp)->m_next; 1765 } 1766 1767 if (inp->inp_flags & INP_RECVDSTADDR) { 1768 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1769 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1770 if (*mp) 1771 mp = &(*mp)->m_next; 1772 } 1773 #ifdef notyet 1774 /* this code is broken and will probably never be fixed. */ 1775 /* options were tossed already */ 1776 if (inp->inp_flags & INP_RECVOPTS) { 1777 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1778 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1779 if (*mp) 1780 mp = &(*mp)->m_next; 1781 } 1782 /* ip_srcroute doesn't do what we want here, need to fix */ 1783 if (inp->inp_flags & INP_RECVRETOPTS) { 1784 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1785 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1786 if (*mp) 1787 mp = &(*mp)->m_next; 1788 } 1789 #endif 1790 if (inp->inp_flags & INP_RECVIF) { 1791 struct sockaddr_dl sdl; 1792 struct ifnet *ifp; 1793 1794 ifp = if_get(m->m_pkthdr.ph_ifidx); 1795 if (ifp == NULL || ifp->if_sadl == NULL) { 1796 memset(&sdl, 0, sizeof(sdl)); 1797 sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]); 1798 sdl.sdl_family = AF_LINK; 1799 sdl.sdl_index = ifp != NULL ? ifp->if_index : 0; 1800 sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0; 1801 *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len, 1802 IP_RECVIF, IPPROTO_IP); 1803 } else { 1804 *mp = sbcreatecontrol((caddr_t) ifp->if_sadl, 1805 ifp->if_sadl->sdl_len, IP_RECVIF, IPPROTO_IP); 1806 } 1807 if (*mp) 1808 mp = &(*mp)->m_next; 1809 if_put(ifp); 1810 } 1811 if (inp->inp_flags & INP_RECVTTL) { 1812 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1813 sizeof(u_int8_t), IP_RECVTTL, IPPROTO_IP); 1814 if (*mp) 1815 mp = &(*mp)->m_next; 1816 } 1817 if (inp->inp_flags & INP_RECVRTABLE) { 1818 u_int rtableid = inp->inp_rtableid; 1819 1820 #if NPF > 0 1821 if (m && m->m_pkthdr.pf.flags & PF_TAG_DIVERTED) { 1822 struct pf_divert *divert; 1823 1824 divert = pf_find_divert(m); 1825 KASSERT(divert != NULL); 1826 rtableid = divert->rdomain; 1827 } 1828 #endif 1829 1830 *mp = sbcreatecontrol((caddr_t) &rtableid, 1831 sizeof(u_int), IP_RECVRTABLE, IPPROTO_IP); 1832 if (*mp) 1833 mp = &(*mp)->m_next; 1834 } 1835 } 1836 1837 void 1838 ip_send_do_dispatch(void *xmq, int flags) 1839 { 1840 struct mbuf_queue *mq = xmq; 1841 struct mbuf *m; 1842 struct mbuf_list ml; 1843 struct m_tag *mtag; 1844 1845 mq_delist(mq, &ml); 1846 if (ml_empty(&ml)) 1847 return; 1848 1849 NET_LOCK(); 1850 while ((m = ml_dequeue(&ml)) != NULL) { 1851 u_int32_t ipsecflowinfo = 0; 1852 1853 if ((mtag = m_tag_find(m, PACKET_TAG_IPSEC_FLOWINFO, NULL)) 1854 != NULL) { 1855 ipsecflowinfo = *(u_int32_t *)(mtag + 1); 1856 m_tag_delete(m, mtag); 1857 } 1858 ip_output(m, NULL, NULL, flags, NULL, NULL, ipsecflowinfo); 1859 } 1860 NET_UNLOCK(); 1861 } 1862 1863 void 1864 ip_sendraw_dispatch(void *xmq) 1865 { 1866 ip_send_do_dispatch(xmq, IP_RAWOUTPUT); 1867 } 1868 1869 void 1870 ip_send_dispatch(void *xmq) 1871 { 1872 ip_send_do_dispatch(xmq, 0); 1873 } 1874 1875 void 1876 ip_send(struct mbuf *m) 1877 { 1878 mq_enqueue(&ipsend_mq, m); 1879 task_add(net_tq(0), &ipsend_task); 1880 } 1881 1882 void 1883 ip_send_raw(struct mbuf *m) 1884 { 1885 mq_enqueue(&ipsendraw_mq, m); 1886 task_add(net_tq(0), &ipsendraw_task); 1887 } 1888