1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_bootp.h" 36 #include "opt_ipfw.h" 37 #include "opt_ipstealth.h" 38 #include "opt_ipsec.h" 39 #include "opt_route.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/mbuf.h> 44 #include <sys/malloc.h> 45 #include <sys/domain.h> 46 #include <sys/protosw.h> 47 #include <sys/socket.h> 48 #include <sys/time.h> 49 #include <sys/kernel.h> 50 #include <sys/lock.h> 51 #include <sys/rwlock.h> 52 #include <sys/syslog.h> 53 #include <sys/sysctl.h> 54 55 #include <net/pfil.h> 56 #include <net/if.h> 57 #include <net/if_types.h> 58 #include <net/if_var.h> 59 #include <net/if_dl.h> 60 #include <net/route.h> 61 #include <net/netisr.h> 62 #include <net/vnet.h> 63 #include <net/flowtable.h> 64 65 #include <netinet/in.h> 66 #include <netinet/in_systm.h> 67 #include <netinet/in_var.h> 68 #include <netinet/ip.h> 69 #include <netinet/in_pcb.h> 70 #include <netinet/ip_var.h> 71 #include <netinet/ip_fw.h> 72 #include <netinet/ip_icmp.h> 73 #include <netinet/ip_options.h> 74 #include <machine/in_cksum.h> 75 #include <netinet/ip_carp.h> 76 #ifdef IPSEC 77 #include <netinet/ip_ipsec.h> 78 #endif /* IPSEC */ 79 80 #include <sys/socketvar.h> 81 82 #include <security/mac/mac_framework.h> 83 84 #ifdef CTASSERT 85 CTASSERT(sizeof(struct ip) == 20); 86 #endif 87 88 struct rwlock in_ifaddr_lock; 89 RW_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock"); 90 91 VNET_DEFINE(int, rsvp_on); 92 93 VNET_DEFINE(int, ipforwarding); 94 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 95 &VNET_NAME(ipforwarding), 0, 96 "Enable IP forwarding between interfaces"); 97 98 static VNET_DEFINE(int, ipsendredirects) = 1; /* XXX */ 99 #define V_ipsendredirects VNET(ipsendredirects) 100 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 101 &VNET_NAME(ipsendredirects), 0, 102 "Enable sending IP redirects"); 103 104 static VNET_DEFINE(int, ip_keepfaith); 105 #define V_ip_keepfaith VNET(ip_keepfaith) 106 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW, 107 &VNET_NAME(ip_keepfaith), 0, 108 "Enable packet capture for FAITH IPv4->IPv6 translater daemon"); 109 110 static VNET_DEFINE(int, ip_sendsourcequench); 111 #define V_ip_sendsourcequench VNET(ip_sendsourcequench) 112 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 113 &VNET_NAME(ip_sendsourcequench), 0, 114 "Enable the transmission of source quench packets"); 115 116 VNET_DEFINE(int, ip_do_randomid); 117 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 118 &VNET_NAME(ip_do_randomid), 0, 119 "Assign random ip_id values"); 120 121 /* 122 * XXX - Setting ip_checkinterface mostly implements the receive side of 123 * the Strong ES model described in RFC 1122, but since the routing table 124 * and transmit implementation do not implement the Strong ES model, 125 * setting this to 1 results in an odd hybrid. 126 * 127 * XXX - ip_checkinterface currently must be disabled if you use ipnat 128 * to translate the destination address to another local interface. 129 * 130 * XXX - ip_checkinterface must be disabled if you add IP aliases 131 * to the loopback interface instead of the interface where the 132 * packets for those addresses are received. 133 */ 134 static VNET_DEFINE(int, ip_checkinterface); 135 #define V_ip_checkinterface VNET(ip_checkinterface) 136 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 137 &VNET_NAME(ip_checkinterface), 0, 138 "Verify packet arrives on correct interface"); 139 140 VNET_DEFINE(struct pfil_head, inet_pfil_hook); /* Packet filter hooks */ 141 142 static struct netisr_handler ip_nh = { 143 .nh_name = "ip", 144 .nh_handler = ip_input, 145 .nh_proto = NETISR_IP, 146 .nh_policy = NETISR_POLICY_FLOW, 147 }; 148 149 extern struct domain inetdomain; 150 extern struct protosw inetsw[]; 151 u_char ip_protox[IPPROTO_MAX]; 152 VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */ 153 VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */ 154 VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */ 155 156 VNET_DEFINE(struct ipstat, ipstat); 157 SYSCTL_VNET_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW, 158 &VNET_NAME(ipstat), ipstat, 159 "IP statistics (struct ipstat, netinet/ip_var.h)"); 160 161 static VNET_DEFINE(uma_zone_t, ipq_zone); 162 static VNET_DEFINE(TAILQ_HEAD(ipqhead, ipq), ipq[IPREASS_NHASH]); 163 static struct mtx ipqlock; 164 165 #define V_ipq_zone VNET(ipq_zone) 166 #define V_ipq VNET(ipq) 167 168 #define IPQ_LOCK() mtx_lock(&ipqlock) 169 #define IPQ_UNLOCK() mtx_unlock(&ipqlock) 170 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF) 171 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED) 172 173 static void maxnipq_update(void); 174 static void ipq_zone_change(void *); 175 static void ip_drain_locked(void); 176 177 static VNET_DEFINE(int, maxnipq); /* Administrative limit on # reass queues. */ 178 static VNET_DEFINE(int, nipq); /* Total # of reass queues */ 179 #define V_maxnipq VNET(maxnipq) 180 #define V_nipq VNET(nipq) 181 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, 182 &VNET_NAME(nipq), 0, 183 "Current number of IPv4 fragment reassembly queue entries"); 184 185 static VNET_DEFINE(int, maxfragsperpacket); 186 #define V_maxfragsperpacket VNET(maxfragsperpacket) 187 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 188 &VNET_NAME(maxfragsperpacket), 0, 189 "Maximum number of IPv4 fragments allowed per packet"); 190 191 #ifdef IPCTL_DEFMTU 192 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 193 &ip_mtu, 0, "Default MTU"); 194 #endif 195 196 #ifdef IPSTEALTH 197 VNET_DEFINE(int, ipstealth); 198 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 199 &VNET_NAME(ipstealth), 0, 200 "IP stealth mode, no TTL decrementation on forwarding"); 201 #endif 202 203 #ifdef FLOWTABLE 204 static VNET_DEFINE(int, ip_output_flowtable_size) = 2048; 205 VNET_DEFINE(struct flowtable *, ip_ft); 206 #define V_ip_output_flowtable_size VNET(ip_output_flowtable_size) 207 208 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, output_flowtable_size, CTLFLAG_RDTUN, 209 &VNET_NAME(ip_output_flowtable_size), 2048, 210 "number of entries in the per-cpu output flow caches"); 211 #endif 212 213 static void ip_freef(struct ipqhead *, struct ipq *); 214 215 /* 216 * Kernel module interface for updating ipstat. The argument is an index 217 * into ipstat treated as an array of u_long. While this encodes the general 218 * layout of ipstat into the caller, it doesn't encode its location, so that 219 * future changes to add, for example, per-CPU stats support won't cause 220 * binary compatibility problems for kernel modules. 221 */ 222 void 223 kmod_ipstat_inc(int statnum) 224 { 225 226 (*((u_long *)&V_ipstat + statnum))++; 227 } 228 229 void 230 kmod_ipstat_dec(int statnum) 231 { 232 233 (*((u_long *)&V_ipstat + statnum))--; 234 } 235 236 static int 237 sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS) 238 { 239 int error, qlimit; 240 241 netisr_getqlimit(&ip_nh, &qlimit); 242 error = sysctl_handle_int(oidp, &qlimit, 0, req); 243 if (error || !req->newptr) 244 return (error); 245 if (qlimit < 1) 246 return (EINVAL); 247 return (netisr_setqlimit(&ip_nh, qlimit)); 248 } 249 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, 250 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I", 251 "Maximum size of the IP input queue"); 252 253 static int 254 sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS) 255 { 256 u_int64_t qdrops_long; 257 int error, qdrops; 258 259 netisr_getqdrops(&ip_nh, &qdrops_long); 260 qdrops = qdrops_long; 261 error = sysctl_handle_int(oidp, &qdrops, 0, req); 262 if (error || !req->newptr) 263 return (error); 264 if (qdrops != 0) 265 return (EINVAL); 266 netisr_clearqdrops(&ip_nh); 267 return (0); 268 } 269 270 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, 271 CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I", 272 "Number of packets dropped from the IP input queue"); 273 274 /* 275 * IP initialization: fill in IP protocol switch table. 276 * All protocols not implemented in kernel go to raw IP protocol handler. 277 */ 278 void 279 ip_init(void) 280 { 281 struct protosw *pr; 282 int i; 283 284 V_ip_id = time_second & 0xffff; 285 286 TAILQ_INIT(&V_in_ifaddrhead); 287 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask); 288 289 /* Initialize IP reassembly queue. */ 290 for (i = 0; i < IPREASS_NHASH; i++) 291 TAILQ_INIT(&V_ipq[i]); 292 V_maxnipq = nmbclusters / 32; 293 V_maxfragsperpacket = 16; 294 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, 295 NULL, UMA_ALIGN_PTR, 0); 296 maxnipq_update(); 297 298 /* Initialize packet filter hooks. */ 299 V_inet_pfil_hook.ph_type = PFIL_TYPE_AF; 300 V_inet_pfil_hook.ph_af = AF_INET; 301 if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0) 302 printf("%s: WARNING: unable to register pfil hook, " 303 "error %d\n", __func__, i); 304 305 #ifdef FLOWTABLE 306 if (TUNABLE_INT_FETCH("net.inet.ip.output_flowtable_size", 307 &V_ip_output_flowtable_size)) { 308 if (V_ip_output_flowtable_size < 256) 309 V_ip_output_flowtable_size = 256; 310 if (!powerof2(V_ip_output_flowtable_size)) { 311 printf("flowtable must be power of 2 size\n"); 312 V_ip_output_flowtable_size = 2048; 313 } 314 } else { 315 /* 316 * round up to the next power of 2 317 */ 318 V_ip_output_flowtable_size = 1 << fls((1024 + maxusers * 64)-1); 319 } 320 V_ip_ft = flowtable_alloc("ipv4", V_ip_output_flowtable_size, FL_PCPU); 321 #endif 322 323 /* Skip initialization of globals for non-default instances. */ 324 if (!IS_DEFAULT_VNET(curvnet)) 325 return; 326 327 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 328 if (pr == NULL) 329 panic("ip_init: PF_INET not found"); 330 331 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */ 332 for (i = 0; i < IPPROTO_MAX; i++) 333 ip_protox[i] = pr - inetsw; 334 /* 335 * Cycle through IP protocols and put them into the appropriate place 336 * in ip_protox[]. 337 */ 338 for (pr = inetdomain.dom_protosw; 339 pr < inetdomain.dom_protoswNPROTOSW; pr++) 340 if (pr->pr_domain->dom_family == PF_INET && 341 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) { 342 /* Be careful to only index valid IP protocols. */ 343 if (pr->pr_protocol < IPPROTO_MAX) 344 ip_protox[pr->pr_protocol] = pr - inetsw; 345 } 346 347 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, 348 NULL, EVENTHANDLER_PRI_ANY); 349 350 /* Initialize various other remaining things. */ 351 IPQ_LOCK_INIT(); 352 netisr_register(&ip_nh); 353 } 354 355 #ifdef VIMAGE 356 void 357 ip_destroy(void) 358 { 359 360 /* Cleanup in_ifaddr hash table; should be empty. */ 361 hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask); 362 363 IPQ_LOCK(); 364 ip_drain_locked(); 365 IPQ_UNLOCK(); 366 367 uma_zdestroy(V_ipq_zone); 368 } 369 #endif 370 371 /* 372 * Ip input routine. Checksum and byte swap header. If fragmented 373 * try to reassemble. Process options. Pass to next level. 374 */ 375 void 376 ip_input(struct mbuf *m) 377 { 378 struct ip *ip = NULL; 379 struct in_ifaddr *ia = NULL; 380 struct ifaddr *ifa; 381 struct ifnet *ifp; 382 int checkif, hlen = 0; 383 u_short sum; 384 int dchg = 0; /* dest changed after fw */ 385 struct in_addr odst; /* original dst address */ 386 387 M_ASSERTPKTHDR(m); 388 389 if (m->m_flags & M_FASTFWD_OURS) { 390 /* 391 * Firewall or NAT changed destination to local. 392 * We expect ip_len and ip_off to be in host byte order. 393 */ 394 m->m_flags &= ~M_FASTFWD_OURS; 395 /* Set up some basics that will be used later. */ 396 ip = mtod(m, struct ip *); 397 hlen = ip->ip_hl << 2; 398 goto ours; 399 } 400 401 IPSTAT_INC(ips_total); 402 403 if (m->m_pkthdr.len < sizeof(struct ip)) 404 goto tooshort; 405 406 if (m->m_len < sizeof (struct ip) && 407 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 408 IPSTAT_INC(ips_toosmall); 409 return; 410 } 411 ip = mtod(m, struct ip *); 412 413 if (ip->ip_v != IPVERSION) { 414 IPSTAT_INC(ips_badvers); 415 goto bad; 416 } 417 418 hlen = ip->ip_hl << 2; 419 if (hlen < sizeof(struct ip)) { /* minimum header length */ 420 IPSTAT_INC(ips_badhlen); 421 goto bad; 422 } 423 if (hlen > m->m_len) { 424 if ((m = m_pullup(m, hlen)) == NULL) { 425 IPSTAT_INC(ips_badhlen); 426 return; 427 } 428 ip = mtod(m, struct ip *); 429 } 430 431 /* 127/8 must not appear on wire - RFC1122 */ 432 ifp = m->m_pkthdr.rcvif; 433 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 434 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 435 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 436 IPSTAT_INC(ips_badaddr); 437 goto bad; 438 } 439 } 440 441 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 442 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 443 } else { 444 if (hlen == sizeof(struct ip)) { 445 sum = in_cksum_hdr(ip); 446 } else { 447 sum = in_cksum(m, hlen); 448 } 449 } 450 if (sum) { 451 IPSTAT_INC(ips_badsum); 452 goto bad; 453 } 454 455 #ifdef ALTQ 456 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 457 /* packet is dropped by traffic conditioner */ 458 return; 459 #endif 460 461 /* 462 * Convert fields to host representation. 463 */ 464 ip->ip_len = ntohs(ip->ip_len); 465 if (ip->ip_len < hlen) { 466 IPSTAT_INC(ips_badlen); 467 goto bad; 468 } 469 ip->ip_off = ntohs(ip->ip_off); 470 471 /* 472 * Check that the amount of data in the buffers 473 * is as at least much as the IP header would have us expect. 474 * Trim mbufs if longer than we expect. 475 * Drop packet if shorter than we expect. 476 */ 477 if (m->m_pkthdr.len < ip->ip_len) { 478 tooshort: 479 IPSTAT_INC(ips_tooshort); 480 goto bad; 481 } 482 if (m->m_pkthdr.len > ip->ip_len) { 483 if (m->m_len == m->m_pkthdr.len) { 484 m->m_len = ip->ip_len; 485 m->m_pkthdr.len = ip->ip_len; 486 } else 487 m_adj(m, ip->ip_len - m->m_pkthdr.len); 488 } 489 #ifdef IPSEC 490 /* 491 * Bypass packet filtering for packets from a tunnel (gif). 492 */ 493 if (ip_ipsec_filtertunnel(m)) 494 goto passin; 495 #endif /* IPSEC */ 496 497 /* 498 * Run through list of hooks for input packets. 499 * 500 * NB: Beware of the destination address changing (e.g. 501 * by NAT rewriting). When this happens, tell 502 * ip_forward to do the right thing. 503 */ 504 505 /* Jump over all PFIL processing if hooks are not active. */ 506 if (!PFIL_HOOKED(&V_inet_pfil_hook)) 507 goto passin; 508 509 odst = ip->ip_dst; 510 if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0) 511 return; 512 if (m == NULL) /* consumed by filter */ 513 return; 514 515 ip = mtod(m, struct ip *); 516 dchg = (odst.s_addr != ip->ip_dst.s_addr); 517 ifp = m->m_pkthdr.rcvif; 518 519 #ifdef IPFIREWALL_FORWARD 520 if (m->m_flags & M_FASTFWD_OURS) { 521 m->m_flags &= ~M_FASTFWD_OURS; 522 goto ours; 523 } 524 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) { 525 /* 526 * Directly ship the packet on. This allows forwarding 527 * packets originally destined to us to some other directly 528 * connected host. 529 */ 530 ip_forward(m, dchg); 531 return; 532 } 533 #endif /* IPFIREWALL_FORWARD */ 534 535 passin: 536 /* 537 * Process options and, if not destined for us, 538 * ship it on. ip_dooptions returns 1 when an 539 * error was detected (causing an icmp message 540 * to be sent and the original packet to be freed). 541 */ 542 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0)) 543 return; 544 545 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 546 * matter if it is destined to another node, or whether it is 547 * a multicast one, RSVP wants it! and prevents it from being forwarded 548 * anywhere else. Also checks if the rsvp daemon is running before 549 * grabbing the packet. 550 */ 551 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP) 552 goto ours; 553 554 /* 555 * Check our list of addresses, to see if the packet is for us. 556 * If we don't have any addresses, assume any unicast packet 557 * we receive might be for us (and let the upper layers deal 558 * with it). 559 */ 560 if (TAILQ_EMPTY(&V_in_ifaddrhead) && 561 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 562 goto ours; 563 564 /* 565 * Enable a consistency check between the destination address 566 * and the arrival interface for a unicast packet (the RFC 1122 567 * strong ES model) if IP forwarding is disabled and the packet 568 * is not locally generated and the packet is not subject to 569 * 'ipfw fwd'. 570 * 571 * XXX - Checking also should be disabled if the destination 572 * address is ipnat'ed to a different interface. 573 * 574 * XXX - Checking is incompatible with IP aliases added 575 * to the loopback interface instead of the interface where 576 * the packets are received. 577 * 578 * XXX - This is the case for carp vhost IPs as well so we 579 * insert a workaround. If the packet got here, we already 580 * checked with carp_iamatch() and carp_forus(). 581 */ 582 checkif = V_ip_checkinterface && (V_ipforwarding == 0) && 583 ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) && 584 ifp->if_carp == NULL && (dchg == 0); 585 586 /* 587 * Check for exact addresses in the hash bucket. 588 */ 589 /* IN_IFADDR_RLOCK(); */ 590 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 591 /* 592 * If the address matches, verify that the packet 593 * arrived via the correct interface if checking is 594 * enabled. 595 */ 596 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr && 597 (!checkif || ia->ia_ifp == ifp)) { 598 ifa_ref(&ia->ia_ifa); 599 /* IN_IFADDR_RUNLOCK(); */ 600 goto ours; 601 } 602 } 603 /* IN_IFADDR_RUNLOCK(); */ 604 605 /* 606 * Check for broadcast addresses. 607 * 608 * Only accept broadcast packets that arrive via the matching 609 * interface. Reception of forwarded directed broadcasts would 610 * be handled via ip_forward() and ether_output() with the loopback 611 * into the stack for SIMPLEX interfaces handled by ether_output(). 612 */ 613 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) { 614 IF_ADDR_LOCK(ifp); 615 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 616 if (ifa->ifa_addr->sa_family != AF_INET) 617 continue; 618 ia = ifatoia(ifa); 619 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 620 ip->ip_dst.s_addr) { 621 ifa_ref(ifa); 622 IF_ADDR_UNLOCK(ifp); 623 goto ours; 624 } 625 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) { 626 ifa_ref(ifa); 627 IF_ADDR_UNLOCK(ifp); 628 goto ours; 629 } 630 #ifdef BOOTP_COMPAT 631 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) { 632 ifa_ref(ifa); 633 IF_ADDR_UNLOCK(ifp); 634 goto ours; 635 } 636 #endif 637 } 638 IF_ADDR_UNLOCK(ifp); 639 ia = NULL; 640 } 641 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */ 642 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) { 643 IPSTAT_INC(ips_cantforward); 644 m_freem(m); 645 return; 646 } 647 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 648 if (V_ip_mrouter) { 649 /* 650 * If we are acting as a multicast router, all 651 * incoming multicast packets are passed to the 652 * kernel-level multicast forwarding function. 653 * The packet is returned (relatively) intact; if 654 * ip_mforward() returns a non-zero value, the packet 655 * must be discarded, else it may be accepted below. 656 */ 657 if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) { 658 IPSTAT_INC(ips_cantforward); 659 m_freem(m); 660 return; 661 } 662 663 /* 664 * The process-level routing daemon needs to receive 665 * all multicast IGMP packets, whether or not this 666 * host belongs to their destination groups. 667 */ 668 if (ip->ip_p == IPPROTO_IGMP) 669 goto ours; 670 IPSTAT_INC(ips_forward); 671 } 672 /* 673 * Assume the packet is for us, to avoid prematurely taking 674 * a lock on the in_multi hash. Protocols must perform 675 * their own filtering and update statistics accordingly. 676 */ 677 goto ours; 678 } 679 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 680 goto ours; 681 if (ip->ip_dst.s_addr == INADDR_ANY) 682 goto ours; 683 684 /* 685 * FAITH(Firewall Aided Internet Translator) 686 */ 687 if (ifp && ifp->if_type == IFT_FAITH) { 688 if (V_ip_keepfaith) { 689 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP) 690 goto ours; 691 } 692 m_freem(m); 693 return; 694 } 695 696 /* 697 * Not for us; forward if possible and desirable. 698 */ 699 if (V_ipforwarding == 0) { 700 IPSTAT_INC(ips_cantforward); 701 m_freem(m); 702 } else { 703 #ifdef IPSEC 704 if (ip_ipsec_fwd(m)) 705 goto bad; 706 #endif /* IPSEC */ 707 ip_forward(m, dchg); 708 } 709 return; 710 711 ours: 712 #ifdef IPSTEALTH 713 /* 714 * IPSTEALTH: Process non-routing options only 715 * if the packet is destined for us. 716 */ 717 if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1)) { 718 if (ia != NULL) 719 ifa_free(&ia->ia_ifa); 720 return; 721 } 722 #endif /* IPSTEALTH */ 723 724 /* Count the packet in the ip address stats */ 725 if (ia != NULL) { 726 ia->ia_ifa.if_ipackets++; 727 ia->ia_ifa.if_ibytes += m->m_pkthdr.len; 728 ifa_free(&ia->ia_ifa); 729 } 730 731 /* 732 * Attempt reassembly; if it succeeds, proceed. 733 * ip_reass() will return a different mbuf. 734 */ 735 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 736 m = ip_reass(m); 737 if (m == NULL) 738 return; 739 ip = mtod(m, struct ip *); 740 /* Get the header length of the reassembled packet */ 741 hlen = ip->ip_hl << 2; 742 } 743 744 /* 745 * Further protocols expect the packet length to be w/o the 746 * IP header. 747 */ 748 ip->ip_len -= hlen; 749 750 #ifdef IPSEC 751 /* 752 * enforce IPsec policy checking if we are seeing last header. 753 * note that we do not visit this with protocols with pcb layer 754 * code - like udp/tcp/raw ip. 755 */ 756 if (ip_ipsec_input(m)) 757 goto bad; 758 #endif /* IPSEC */ 759 760 /* 761 * Switch out to protocol's input routine. 762 */ 763 IPSTAT_INC(ips_delivered); 764 765 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 766 return; 767 bad: 768 m_freem(m); 769 } 770 771 /* 772 * After maxnipq has been updated, propagate the change to UMA. The UMA zone 773 * max has slightly different semantics than the sysctl, for historical 774 * reasons. 775 */ 776 static void 777 maxnipq_update(void) 778 { 779 780 /* 781 * -1 for unlimited allocation. 782 */ 783 if (V_maxnipq < 0) 784 uma_zone_set_max(V_ipq_zone, 0); 785 /* 786 * Positive number for specific bound. 787 */ 788 if (V_maxnipq > 0) 789 uma_zone_set_max(V_ipq_zone, V_maxnipq); 790 /* 791 * Zero specifies no further fragment queue allocation -- set the 792 * bound very low, but rely on implementation elsewhere to actually 793 * prevent allocation and reclaim current queues. 794 */ 795 if (V_maxnipq == 0) 796 uma_zone_set_max(V_ipq_zone, 1); 797 } 798 799 static void 800 ipq_zone_change(void *tag) 801 { 802 803 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) { 804 V_maxnipq = nmbclusters / 32; 805 maxnipq_update(); 806 } 807 } 808 809 static int 810 sysctl_maxnipq(SYSCTL_HANDLER_ARGS) 811 { 812 int error, i; 813 814 i = V_maxnipq; 815 error = sysctl_handle_int(oidp, &i, 0, req); 816 if (error || !req->newptr) 817 return (error); 818 819 /* 820 * XXXRW: Might be a good idea to sanity check the argument and place 821 * an extreme upper bound. 822 */ 823 if (i < -1) 824 return (EINVAL); 825 V_maxnipq = i; 826 maxnipq_update(); 827 return (0); 828 } 829 830 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW, 831 NULL, 0, sysctl_maxnipq, "I", 832 "Maximum number of IPv4 fragment reassembly queue entries"); 833 834 /* 835 * Take incoming datagram fragment and try to reassemble it into 836 * whole datagram. If the argument is the first fragment or one 837 * in between the function will return NULL and store the mbuf 838 * in the fragment chain. If the argument is the last fragment 839 * the packet will be reassembled and the pointer to the new 840 * mbuf returned for further processing. Only m_tags attached 841 * to the first packet/fragment are preserved. 842 * The IP header is *NOT* adjusted out of iplen. 843 */ 844 struct mbuf * 845 ip_reass(struct mbuf *m) 846 { 847 struct ip *ip; 848 struct mbuf *p, *q, *nq, *t; 849 struct ipq *fp = NULL; 850 struct ipqhead *head; 851 int i, hlen, next; 852 u_int8_t ecn, ecn0; 853 u_short hash; 854 855 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 856 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) { 857 IPSTAT_INC(ips_fragments); 858 IPSTAT_INC(ips_fragdropped); 859 m_freem(m); 860 return (NULL); 861 } 862 863 ip = mtod(m, struct ip *); 864 hlen = ip->ip_hl << 2; 865 866 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 867 head = &V_ipq[hash]; 868 IPQ_LOCK(); 869 870 /* 871 * Look for queue of fragments 872 * of this datagram. 873 */ 874 TAILQ_FOREACH(fp, head, ipq_list) 875 if (ip->ip_id == fp->ipq_id && 876 ip->ip_src.s_addr == fp->ipq_src.s_addr && 877 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 878 #ifdef MAC 879 mac_ipq_match(m, fp) && 880 #endif 881 ip->ip_p == fp->ipq_p) 882 goto found; 883 884 fp = NULL; 885 886 /* 887 * Attempt to trim the number of allocated fragment queues if it 888 * exceeds the administrative limit. 889 */ 890 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) { 891 /* 892 * drop something from the tail of the current queue 893 * before proceeding further 894 */ 895 struct ipq *q = TAILQ_LAST(head, ipqhead); 896 if (q == NULL) { /* gak */ 897 for (i = 0; i < IPREASS_NHASH; i++) { 898 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead); 899 if (r) { 900 IPSTAT_ADD(ips_fragtimeout, 901 r->ipq_nfrags); 902 ip_freef(&V_ipq[i], r); 903 break; 904 } 905 } 906 } else { 907 IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags); 908 ip_freef(head, q); 909 } 910 } 911 912 found: 913 /* 914 * Adjust ip_len to not reflect header, 915 * convert offset of this to bytes. 916 */ 917 ip->ip_len -= hlen; 918 if (ip->ip_off & IP_MF) { 919 /* 920 * Make sure that fragments have a data length 921 * that's a non-zero multiple of 8 bytes. 922 */ 923 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 924 IPSTAT_INC(ips_toosmall); /* XXX */ 925 goto dropfrag; 926 } 927 m->m_flags |= M_FRAG; 928 } else 929 m->m_flags &= ~M_FRAG; 930 ip->ip_off <<= 3; 931 932 933 /* 934 * Attempt reassembly; if it succeeds, proceed. 935 * ip_reass() will return a different mbuf. 936 */ 937 IPSTAT_INC(ips_fragments); 938 m->m_pkthdr.header = ip; 939 940 /* Previous ip_reass() started here. */ 941 /* 942 * Presence of header sizes in mbufs 943 * would confuse code below. 944 */ 945 m->m_data += hlen; 946 m->m_len -= hlen; 947 948 /* 949 * If first fragment to arrive, create a reassembly queue. 950 */ 951 if (fp == NULL) { 952 fp = uma_zalloc(V_ipq_zone, M_NOWAIT); 953 if (fp == NULL) 954 goto dropfrag; 955 #ifdef MAC 956 if (mac_ipq_init(fp, M_NOWAIT) != 0) { 957 uma_zfree(V_ipq_zone, fp); 958 fp = NULL; 959 goto dropfrag; 960 } 961 mac_ipq_create(m, fp); 962 #endif 963 TAILQ_INSERT_HEAD(head, fp, ipq_list); 964 V_nipq++; 965 fp->ipq_nfrags = 1; 966 fp->ipq_ttl = IPFRAGTTL; 967 fp->ipq_p = ip->ip_p; 968 fp->ipq_id = ip->ip_id; 969 fp->ipq_src = ip->ip_src; 970 fp->ipq_dst = ip->ip_dst; 971 fp->ipq_frags = m; 972 m->m_nextpkt = NULL; 973 goto done; 974 } else { 975 fp->ipq_nfrags++; 976 #ifdef MAC 977 mac_ipq_update(m, fp); 978 #endif 979 } 980 981 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 982 983 /* 984 * Handle ECN by comparing this segment with the first one; 985 * if CE is set, do not lose CE. 986 * drop if CE and not-ECT are mixed for the same packet. 987 */ 988 ecn = ip->ip_tos & IPTOS_ECN_MASK; 989 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; 990 if (ecn == IPTOS_ECN_CE) { 991 if (ecn0 == IPTOS_ECN_NOTECT) 992 goto dropfrag; 993 if (ecn0 != IPTOS_ECN_CE) 994 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; 995 } 996 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 997 goto dropfrag; 998 999 /* 1000 * Find a segment which begins after this one does. 1001 */ 1002 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 1003 if (GETIP(q)->ip_off > ip->ip_off) 1004 break; 1005 1006 /* 1007 * If there is a preceding segment, it may provide some of 1008 * our data already. If so, drop the data from the incoming 1009 * segment. If it provides all of our data, drop us, otherwise 1010 * stick new segment in the proper place. 1011 * 1012 * If some of the data is dropped from the preceding 1013 * segment, then it's checksum is invalidated. 1014 */ 1015 if (p) { 1016 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 1017 if (i > 0) { 1018 if (i >= ip->ip_len) 1019 goto dropfrag; 1020 m_adj(m, i); 1021 m->m_pkthdr.csum_flags = 0; 1022 ip->ip_off += i; 1023 ip->ip_len -= i; 1024 } 1025 m->m_nextpkt = p->m_nextpkt; 1026 p->m_nextpkt = m; 1027 } else { 1028 m->m_nextpkt = fp->ipq_frags; 1029 fp->ipq_frags = m; 1030 } 1031 1032 /* 1033 * While we overlap succeeding segments trim them or, 1034 * if they are completely covered, dequeue them. 1035 */ 1036 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 1037 q = nq) { 1038 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off; 1039 if (i < GETIP(q)->ip_len) { 1040 GETIP(q)->ip_len -= i; 1041 GETIP(q)->ip_off += i; 1042 m_adj(q, i); 1043 q->m_pkthdr.csum_flags = 0; 1044 break; 1045 } 1046 nq = q->m_nextpkt; 1047 m->m_nextpkt = nq; 1048 IPSTAT_INC(ips_fragdropped); 1049 fp->ipq_nfrags--; 1050 m_freem(q); 1051 } 1052 1053 /* 1054 * Check for complete reassembly and perform frag per packet 1055 * limiting. 1056 * 1057 * Frag limiting is performed here so that the nth frag has 1058 * a chance to complete the packet before we drop the packet. 1059 * As a result, n+1 frags are actually allowed per packet, but 1060 * only n will ever be stored. (n = maxfragsperpacket.) 1061 * 1062 */ 1063 next = 0; 1064 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1065 if (GETIP(q)->ip_off != next) { 1066 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1067 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1068 ip_freef(head, fp); 1069 } 1070 goto done; 1071 } 1072 next += GETIP(q)->ip_len; 1073 } 1074 /* Make sure the last packet didn't have the IP_MF flag */ 1075 if (p->m_flags & M_FRAG) { 1076 if (fp->ipq_nfrags > V_maxfragsperpacket) { 1077 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1078 ip_freef(head, fp); 1079 } 1080 goto done; 1081 } 1082 1083 /* 1084 * Reassembly is complete. Make sure the packet is a sane size. 1085 */ 1086 q = fp->ipq_frags; 1087 ip = GETIP(q); 1088 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { 1089 IPSTAT_INC(ips_toolong); 1090 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); 1091 ip_freef(head, fp); 1092 goto done; 1093 } 1094 1095 /* 1096 * Concatenate fragments. 1097 */ 1098 m = q; 1099 t = m->m_next; 1100 m->m_next = NULL; 1101 m_cat(m, t); 1102 nq = q->m_nextpkt; 1103 q->m_nextpkt = NULL; 1104 for (q = nq; q != NULL; q = nq) { 1105 nq = q->m_nextpkt; 1106 q->m_nextpkt = NULL; 1107 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1108 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1109 m_cat(m, q); 1110 } 1111 /* 1112 * In order to do checksumming faster we do 'end-around carry' here 1113 * (and not in for{} loop), though it implies we are not going to 1114 * reassemble more than 64k fragments. 1115 */ 1116 m->m_pkthdr.csum_data = 1117 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16); 1118 #ifdef MAC 1119 mac_ipq_reassemble(fp, m); 1120 mac_ipq_destroy(fp); 1121 #endif 1122 1123 /* 1124 * Create header for new ip packet by modifying header of first 1125 * packet; dequeue and discard fragment reassembly header. 1126 * Make header visible. 1127 */ 1128 ip->ip_len = (ip->ip_hl << 2) + next; 1129 ip->ip_src = fp->ipq_src; 1130 ip->ip_dst = fp->ipq_dst; 1131 TAILQ_REMOVE(head, fp, ipq_list); 1132 V_nipq--; 1133 uma_zfree(V_ipq_zone, fp); 1134 m->m_len += (ip->ip_hl << 2); 1135 m->m_data -= (ip->ip_hl << 2); 1136 /* some debugging cruft by sklower, below, will go away soon */ 1137 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ 1138 m_fixhdr(m); 1139 IPSTAT_INC(ips_reassembled); 1140 IPQ_UNLOCK(); 1141 return (m); 1142 1143 dropfrag: 1144 IPSTAT_INC(ips_fragdropped); 1145 if (fp != NULL) 1146 fp->ipq_nfrags--; 1147 m_freem(m); 1148 done: 1149 IPQ_UNLOCK(); 1150 return (NULL); 1151 1152 #undef GETIP 1153 } 1154 1155 /* 1156 * Free a fragment reassembly header and all 1157 * associated datagrams. 1158 */ 1159 static void 1160 ip_freef(struct ipqhead *fhp, struct ipq *fp) 1161 { 1162 struct mbuf *q; 1163 1164 IPQ_LOCK_ASSERT(); 1165 1166 while (fp->ipq_frags) { 1167 q = fp->ipq_frags; 1168 fp->ipq_frags = q->m_nextpkt; 1169 m_freem(q); 1170 } 1171 TAILQ_REMOVE(fhp, fp, ipq_list); 1172 uma_zfree(V_ipq_zone, fp); 1173 V_nipq--; 1174 } 1175 1176 /* 1177 * IP timer processing; 1178 * if a timer expires on a reassembly 1179 * queue, discard it. 1180 */ 1181 void 1182 ip_slowtimo(void) 1183 { 1184 VNET_ITERATOR_DECL(vnet_iter); 1185 struct ipq *fp; 1186 int i; 1187 1188 VNET_LIST_RLOCK_NOSLEEP(); 1189 IPQ_LOCK(); 1190 VNET_FOREACH(vnet_iter) { 1191 CURVNET_SET(vnet_iter); 1192 for (i = 0; i < IPREASS_NHASH; i++) { 1193 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) { 1194 struct ipq *fpp; 1195 1196 fpp = fp; 1197 fp = TAILQ_NEXT(fp, ipq_list); 1198 if(--fpp->ipq_ttl == 0) { 1199 IPSTAT_ADD(ips_fragtimeout, 1200 fpp->ipq_nfrags); 1201 ip_freef(&V_ipq[i], fpp); 1202 } 1203 } 1204 } 1205 /* 1206 * If we are over the maximum number of fragments 1207 * (due to the limit being lowered), drain off 1208 * enough to get down to the new limit. 1209 */ 1210 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) { 1211 for (i = 0; i < IPREASS_NHASH; i++) { 1212 while (V_nipq > V_maxnipq && 1213 !TAILQ_EMPTY(&V_ipq[i])) { 1214 IPSTAT_ADD(ips_fragdropped, 1215 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1216 ip_freef(&V_ipq[i], 1217 TAILQ_FIRST(&V_ipq[i])); 1218 } 1219 } 1220 } 1221 CURVNET_RESTORE(); 1222 } 1223 IPQ_UNLOCK(); 1224 VNET_LIST_RUNLOCK_NOSLEEP(); 1225 } 1226 1227 /* 1228 * Drain off all datagram fragments. 1229 */ 1230 static void 1231 ip_drain_locked(void) 1232 { 1233 int i; 1234 1235 IPQ_LOCK_ASSERT(); 1236 1237 for (i = 0; i < IPREASS_NHASH; i++) { 1238 while(!TAILQ_EMPTY(&V_ipq[i])) { 1239 IPSTAT_ADD(ips_fragdropped, 1240 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags); 1241 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i])); 1242 } 1243 } 1244 } 1245 1246 void 1247 ip_drain(void) 1248 { 1249 VNET_ITERATOR_DECL(vnet_iter); 1250 1251 VNET_LIST_RLOCK_NOSLEEP(); 1252 IPQ_LOCK(); 1253 VNET_FOREACH(vnet_iter) { 1254 CURVNET_SET(vnet_iter); 1255 ip_drain_locked(); 1256 CURVNET_RESTORE(); 1257 } 1258 IPQ_UNLOCK(); 1259 VNET_LIST_RUNLOCK_NOSLEEP(); 1260 in_rtqdrain(); 1261 } 1262 1263 /* 1264 * The protocol to be inserted into ip_protox[] must be already registered 1265 * in inetsw[], either statically or through pf_proto_register(). 1266 */ 1267 int 1268 ipproto_register(short ipproto) 1269 { 1270 struct protosw *pr; 1271 1272 /* Sanity checks. */ 1273 if (ipproto <= 0 || ipproto >= IPPROTO_MAX) 1274 return (EPROTONOSUPPORT); 1275 1276 /* 1277 * The protocol slot must not be occupied by another protocol 1278 * already. An index pointing to IPPROTO_RAW is unused. 1279 */ 1280 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1281 if (pr == NULL) 1282 return (EPFNOSUPPORT); 1283 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */ 1284 return (EEXIST); 1285 1286 /* Find the protocol position in inetsw[] and set the index. */ 1287 for (pr = inetdomain.dom_protosw; 1288 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 1289 if (pr->pr_domain->dom_family == PF_INET && 1290 pr->pr_protocol && pr->pr_protocol == ipproto) { 1291 ip_protox[pr->pr_protocol] = pr - inetsw; 1292 return (0); 1293 } 1294 } 1295 return (EPROTONOSUPPORT); 1296 } 1297 1298 int 1299 ipproto_unregister(short ipproto) 1300 { 1301 struct protosw *pr; 1302 1303 /* Sanity checks. */ 1304 if (ipproto <= 0 || ipproto >= IPPROTO_MAX) 1305 return (EPROTONOSUPPORT); 1306 1307 /* Check if the protocol was indeed registered. */ 1308 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 1309 if (pr == NULL) 1310 return (EPFNOSUPPORT); 1311 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */ 1312 return (ENOENT); 1313 1314 /* Reset the protocol slot to IPPROTO_RAW. */ 1315 ip_protox[ipproto] = pr - inetsw; 1316 return (0); 1317 } 1318 1319 /* 1320 * Given address of next destination (final or next hop), return (referenced) 1321 * internet address info of interface to be used to get there. 1322 */ 1323 struct in_ifaddr * 1324 ip_rtaddr(struct in_addr dst, u_int fibnum) 1325 { 1326 struct route sro; 1327 struct sockaddr_in *sin; 1328 struct in_ifaddr *ia; 1329 1330 bzero(&sro, sizeof(sro)); 1331 sin = (struct sockaddr_in *)&sro.ro_dst; 1332 sin->sin_family = AF_INET; 1333 sin->sin_len = sizeof(*sin); 1334 sin->sin_addr = dst; 1335 in_rtalloc_ign(&sro, 0, fibnum); 1336 1337 if (sro.ro_rt == NULL) 1338 return (NULL); 1339 1340 ia = ifatoia(sro.ro_rt->rt_ifa); 1341 ifa_ref(&ia->ia_ifa); 1342 RTFREE(sro.ro_rt); 1343 return (ia); 1344 } 1345 1346 u_char inetctlerrmap[PRC_NCMDS] = { 1347 0, 0, 0, 0, 1348 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1349 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1350 EMSGSIZE, EHOSTUNREACH, 0, 0, 1351 0, 0, EHOSTUNREACH, 0, 1352 ENOPROTOOPT, ECONNREFUSED 1353 }; 1354 1355 /* 1356 * Forward a packet. If some error occurs return the sender 1357 * an icmp packet. Note we can't always generate a meaningful 1358 * icmp message because icmp doesn't have a large enough repertoire 1359 * of codes and types. 1360 * 1361 * If not forwarding, just drop the packet. This could be confusing 1362 * if ipforwarding was zero but some routing protocol was advancing 1363 * us as a gateway to somewhere. However, we must let the routing 1364 * protocol deal with that. 1365 * 1366 * The srcrt parameter indicates whether the packet is being forwarded 1367 * via a source route. 1368 */ 1369 void 1370 ip_forward(struct mbuf *m, int srcrt) 1371 { 1372 struct ip *ip = mtod(m, struct ip *); 1373 struct in_ifaddr *ia; 1374 struct mbuf *mcopy; 1375 struct in_addr dest; 1376 struct route ro; 1377 int error, type = 0, code = 0, mtu = 0; 1378 1379 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1380 IPSTAT_INC(ips_cantforward); 1381 m_freem(m); 1382 return; 1383 } 1384 #ifdef IPSTEALTH 1385 if (!V_ipstealth) { 1386 #endif 1387 if (ip->ip_ttl <= IPTTLDEC) { 1388 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1389 0, 0); 1390 return; 1391 } 1392 #ifdef IPSTEALTH 1393 } 1394 #endif 1395 1396 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m)); 1397 #ifndef IPSEC 1398 /* 1399 * 'ia' may be NULL if there is no route for this destination. 1400 * In case of IPsec, Don't discard it just yet, but pass it to 1401 * ip_output in case of outgoing IPsec policy. 1402 */ 1403 if (!srcrt && ia == NULL) { 1404 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 1405 return; 1406 } 1407 #endif 1408 1409 /* 1410 * Save the IP header and at most 8 bytes of the payload, 1411 * in case we need to generate an ICMP message to the src. 1412 * 1413 * XXX this can be optimized a lot by saving the data in a local 1414 * buffer on the stack (72 bytes at most), and only allocating the 1415 * mbuf if really necessary. The vast majority of the packets 1416 * are forwarded without having to send an ICMP back (either 1417 * because unnecessary, or because rate limited), so we are 1418 * really we are wasting a lot of work here. 1419 * 1420 * We don't use m_copy() because it might return a reference 1421 * to a shared cluster. Both this function and ip_output() 1422 * assume exclusive access to the IP header in `m', so any 1423 * data in a cluster may change before we reach icmp_error(). 1424 */ 1425 MGETHDR(mcopy, M_DONTWAIT, m->m_type); 1426 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) { 1427 /* 1428 * It's probably ok if the pkthdr dup fails (because 1429 * the deep copy of the tag chain failed), but for now 1430 * be conservative and just discard the copy since 1431 * code below may some day want the tags. 1432 */ 1433 m_free(mcopy); 1434 mcopy = NULL; 1435 } 1436 if (mcopy != NULL) { 1437 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy)); 1438 mcopy->m_pkthdr.len = mcopy->m_len; 1439 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t)); 1440 } 1441 1442 #ifdef IPSTEALTH 1443 if (!V_ipstealth) { 1444 #endif 1445 ip->ip_ttl -= IPTTLDEC; 1446 #ifdef IPSTEALTH 1447 } 1448 #endif 1449 1450 /* 1451 * If forwarding packet using same interface that it came in on, 1452 * perhaps should send a redirect to sender to shortcut a hop. 1453 * Only send redirect if source is sending directly to us, 1454 * and if packet was not source routed (or has any options). 1455 * Also, don't send redirect if forwarding using a default route 1456 * or a route modified by a redirect. 1457 */ 1458 dest.s_addr = 0; 1459 if (!srcrt && V_ipsendredirects && 1460 ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) { 1461 struct sockaddr_in *sin; 1462 struct rtentry *rt; 1463 1464 bzero(&ro, sizeof(ro)); 1465 sin = (struct sockaddr_in *)&ro.ro_dst; 1466 sin->sin_family = AF_INET; 1467 sin->sin_len = sizeof(*sin); 1468 sin->sin_addr = ip->ip_dst; 1469 in_rtalloc_ign(&ro, 0, M_GETFIB(m)); 1470 1471 rt = ro.ro_rt; 1472 1473 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1474 satosin(rt_key(rt))->sin_addr.s_addr != 0) { 1475 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1476 u_long src = ntohl(ip->ip_src.s_addr); 1477 1478 if (RTA(rt) && 1479 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1480 if (rt->rt_flags & RTF_GATEWAY) 1481 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr; 1482 else 1483 dest.s_addr = ip->ip_dst.s_addr; 1484 /* Router requirements says to only send host redirects */ 1485 type = ICMP_REDIRECT; 1486 code = ICMP_REDIRECT_HOST; 1487 } 1488 } 1489 if (rt) 1490 RTFREE(rt); 1491 } 1492 1493 /* 1494 * Try to cache the route MTU from ip_output so we can consider it for 1495 * the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191. 1496 */ 1497 bzero(&ro, sizeof(ro)); 1498 1499 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL); 1500 1501 if (error == EMSGSIZE && ro.ro_rt) 1502 mtu = ro.ro_rt->rt_rmx.rmx_mtu; 1503 if (ro.ro_rt) 1504 RTFREE(ro.ro_rt); 1505 1506 if (error) 1507 IPSTAT_INC(ips_cantforward); 1508 else { 1509 IPSTAT_INC(ips_forward); 1510 if (type) 1511 IPSTAT_INC(ips_redirectsent); 1512 else { 1513 if (mcopy) 1514 m_freem(mcopy); 1515 if (ia != NULL) 1516 ifa_free(&ia->ia_ifa); 1517 return; 1518 } 1519 } 1520 if (mcopy == NULL) { 1521 if (ia != NULL) 1522 ifa_free(&ia->ia_ifa); 1523 return; 1524 } 1525 1526 switch (error) { 1527 1528 case 0: /* forwarded, but need redirect */ 1529 /* type, code set above */ 1530 break; 1531 1532 case ENETUNREACH: 1533 case EHOSTUNREACH: 1534 case ENETDOWN: 1535 case EHOSTDOWN: 1536 default: 1537 type = ICMP_UNREACH; 1538 code = ICMP_UNREACH_HOST; 1539 break; 1540 1541 case EMSGSIZE: 1542 type = ICMP_UNREACH; 1543 code = ICMP_UNREACH_NEEDFRAG; 1544 1545 #ifdef IPSEC 1546 /* 1547 * If IPsec is configured for this path, 1548 * override any possibly mtu value set by ip_output. 1549 */ 1550 mtu = ip_ipsec_mtu(mcopy, mtu); 1551 #endif /* IPSEC */ 1552 /* 1553 * If the MTU was set before make sure we are below the 1554 * interface MTU. 1555 * If the MTU wasn't set before use the interface mtu or 1556 * fall back to the next smaller mtu step compared to the 1557 * current packet size. 1558 */ 1559 if (mtu != 0) { 1560 if (ia != NULL) 1561 mtu = min(mtu, ia->ia_ifp->if_mtu); 1562 } else { 1563 if (ia != NULL) 1564 mtu = ia->ia_ifp->if_mtu; 1565 else 1566 mtu = ip_next_mtu(ip->ip_len, 0); 1567 } 1568 IPSTAT_INC(ips_cantfrag); 1569 break; 1570 1571 case ENOBUFS: 1572 /* 1573 * A router should not generate ICMP_SOURCEQUENCH as 1574 * required in RFC1812 Requirements for IP Version 4 Routers. 1575 * Source quench could be a big problem under DoS attacks, 1576 * or if the underlying interface is rate-limited. 1577 * Those who need source quench packets may re-enable them 1578 * via the net.inet.ip.sendsourcequench sysctl. 1579 */ 1580 if (V_ip_sendsourcequench == 0) { 1581 m_freem(mcopy); 1582 if (ia != NULL) 1583 ifa_free(&ia->ia_ifa); 1584 return; 1585 } else { 1586 type = ICMP_SOURCEQUENCH; 1587 code = 0; 1588 } 1589 break; 1590 1591 case EACCES: /* ipfw denied packet */ 1592 m_freem(mcopy); 1593 if (ia != NULL) 1594 ifa_free(&ia->ia_ifa); 1595 return; 1596 } 1597 if (ia != NULL) 1598 ifa_free(&ia->ia_ifa); 1599 icmp_error(mcopy, type, code, dest.s_addr, mtu); 1600 } 1601 1602 void 1603 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1604 struct mbuf *m) 1605 { 1606 1607 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) { 1608 struct bintime bt; 1609 1610 bintime(&bt); 1611 if (inp->inp_socket->so_options & SO_BINTIME) { 1612 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt), 1613 SCM_BINTIME, SOL_SOCKET); 1614 if (*mp) 1615 mp = &(*mp)->m_next; 1616 } 1617 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1618 struct timeval tv; 1619 1620 bintime2timeval(&bt, &tv); 1621 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1622 SCM_TIMESTAMP, SOL_SOCKET); 1623 if (*mp) 1624 mp = &(*mp)->m_next; 1625 } 1626 } 1627 if (inp->inp_flags & INP_RECVDSTADDR) { 1628 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1629 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1630 if (*mp) 1631 mp = &(*mp)->m_next; 1632 } 1633 if (inp->inp_flags & INP_RECVTTL) { 1634 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1635 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1636 if (*mp) 1637 mp = &(*mp)->m_next; 1638 } 1639 #ifdef notyet 1640 /* XXX 1641 * Moving these out of udp_input() made them even more broken 1642 * than they already were. 1643 */ 1644 /* options were tossed already */ 1645 if (inp->inp_flags & INP_RECVOPTS) { 1646 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1647 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1648 if (*mp) 1649 mp = &(*mp)->m_next; 1650 } 1651 /* ip_srcroute doesn't do what we want here, need to fix */ 1652 if (inp->inp_flags & INP_RECVRETOPTS) { 1653 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 1654 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1655 if (*mp) 1656 mp = &(*mp)->m_next; 1657 } 1658 #endif 1659 if (inp->inp_flags & INP_RECVIF) { 1660 struct ifnet *ifp; 1661 struct sdlbuf { 1662 struct sockaddr_dl sdl; 1663 u_char pad[32]; 1664 } sdlbuf; 1665 struct sockaddr_dl *sdp; 1666 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1667 1668 if (((ifp = m->m_pkthdr.rcvif)) 1669 && ( ifp->if_index && (ifp->if_index <= V_if_index))) { 1670 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr; 1671 /* 1672 * Change our mind and don't try copy. 1673 */ 1674 if ((sdp->sdl_family != AF_LINK) 1675 || (sdp->sdl_len > sizeof(sdlbuf))) { 1676 goto makedummy; 1677 } 1678 bcopy(sdp, sdl2, sdp->sdl_len); 1679 } else { 1680 makedummy: 1681 sdl2->sdl_len 1682 = offsetof(struct sockaddr_dl, sdl_data[0]); 1683 sdl2->sdl_family = AF_LINK; 1684 sdl2->sdl_index = 0; 1685 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1686 } 1687 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1688 IP_RECVIF, IPPROTO_IP); 1689 if (*mp) 1690 mp = &(*mp)->m_next; 1691 } 1692 } 1693 1694 /* 1695 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the 1696 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on 1697 * locking. This code remains in ip_input.c as ip_mroute.c is optionally 1698 * compiled. 1699 */ 1700 static VNET_DEFINE(int, ip_rsvp_on); 1701 VNET_DEFINE(struct socket *, ip_rsvpd); 1702 1703 #define V_ip_rsvp_on VNET(ip_rsvp_on) 1704 1705 int 1706 ip_rsvp_init(struct socket *so) 1707 { 1708 1709 if (so->so_type != SOCK_RAW || 1710 so->so_proto->pr_protocol != IPPROTO_RSVP) 1711 return EOPNOTSUPP; 1712 1713 if (V_ip_rsvpd != NULL) 1714 return EADDRINUSE; 1715 1716 V_ip_rsvpd = so; 1717 /* 1718 * This may seem silly, but we need to be sure we don't over-increment 1719 * the RSVP counter, in case something slips up. 1720 */ 1721 if (!V_ip_rsvp_on) { 1722 V_ip_rsvp_on = 1; 1723 V_rsvp_on++; 1724 } 1725 1726 return 0; 1727 } 1728 1729 int 1730 ip_rsvp_done(void) 1731 { 1732 1733 V_ip_rsvpd = NULL; 1734 /* 1735 * This may seem silly, but we need to be sure we don't over-decrement 1736 * the RSVP counter, in case something slips up. 1737 */ 1738 if (V_ip_rsvp_on) { 1739 V_ip_rsvp_on = 0; 1740 V_rsvp_on--; 1741 } 1742 return 0; 1743 } 1744 1745 void 1746 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */ 1747 { 1748 1749 if (rsvp_input_p) { /* call the real one if loaded */ 1750 rsvp_input_p(m, off); 1751 return; 1752 } 1753 1754 /* Can still get packets with rsvp_on = 0 if there is a local member 1755 * of the group to which the RSVP packet is addressed. But in this 1756 * case we want to throw the packet away. 1757 */ 1758 1759 if (!V_rsvp_on) { 1760 m_freem(m); 1761 return; 1762 } 1763 1764 if (V_ip_rsvpd != NULL) { 1765 rip_input(m, off); 1766 return; 1767 } 1768 /* Drop the packet */ 1769 m_freem(m); 1770 } 1771