1 /* 2 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved. 3 * Copyright (c) 2003, 2004 The DragonFly Project. All rights reserved. 4 * 5 * This code is derived from software contributed to The DragonFly Project 6 * by Jeffrey M. Hsu. 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 DragonFly Project nor the names of its 17 * contributors may be used to endorse or promote products derived 18 * from this software without specific, prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright (c) 1982, 1986, 1988, 1993 36 * The Regents of the University of California. All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. Neither the name of the University nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 60 * SUCH DAMAGE. 61 * 62 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 63 * $FreeBSD: src/sys/netinet/ip_input.c,v 1.130.2.52 2003/03/07 07:01:28 silby Exp $ 64 */ 65 66 #define _IP_VHL 67 68 #include "opt_bootp.h" 69 #include "opt_ipdn.h" 70 #include "opt_ipdivert.h" 71 #include "opt_ipstealth.h" 72 #include "opt_rss.h" 73 74 #include <sys/param.h> 75 #include <sys/systm.h> 76 #include <sys/mbuf.h> 77 #include <sys/malloc.h> 78 #include <sys/mpipe.h> 79 #include <sys/domain.h> 80 #include <sys/protosw.h> 81 #include <sys/socket.h> 82 #include <sys/time.h> 83 #include <sys/globaldata.h> 84 #include <sys/thread.h> 85 #include <sys/kernel.h> 86 #include <sys/syslog.h> 87 #include <sys/sysctl.h> 88 #include <sys/in_cksum.h> 89 #include <sys/lock.h> 90 91 #include <sys/mplock2.h> 92 93 #include <machine/stdarg.h> 94 95 #include <net/if.h> 96 #include <net/if_types.h> 97 #include <net/if_var.h> 98 #include <net/if_dl.h> 99 #include <net/pfil.h> 100 #include <net/route.h> 101 #include <net/netisr2.h> 102 103 #include <netinet/in.h> 104 #include <netinet/in_systm.h> 105 #include <netinet/in_var.h> 106 #include <netinet/ip.h> 107 #include <netinet/in_pcb.h> 108 #include <netinet/ip_var.h> 109 #include <netinet/ip_icmp.h> 110 #include <netinet/ip_divert.h> 111 #include <netinet/ip_flow.h> 112 113 #include <sys/thread2.h> 114 #include <sys/msgport2.h> 115 #include <net/netmsg2.h> 116 117 #include <sys/socketvar.h> 118 119 #include <net/ipfw/ip_fw.h> 120 #include <net/dummynet/ip_dummynet.h> 121 122 __read_mostly int rsvp_on = 0; 123 __read_mostly static int ip_rsvp_on; 124 struct socket *ip_rsvpd; 125 126 __read_mostly int ipforwarding = 0; 127 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 128 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 129 130 __read_mostly static int ipsendredirects = 1; /* XXX */ 131 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 132 &ipsendredirects, 0, "Enable sending IP redirects"); 133 134 __read_mostly int ip_defttl = IPDEFTTL; 135 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 136 &ip_defttl, 0, "Maximum TTL on IP packets"); 137 138 __read_mostly static int ip_dosourceroute = 0; 139 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 140 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 141 142 __read_mostly static int ip_acceptsourceroute = 0; 143 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 144 CTLFLAG_RW, &ip_acceptsourceroute, 0, 145 "Enable accepting source routed IP packets"); 146 147 __read_mostly static int maxnipq; 148 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW, 149 &maxnipq, 0, 150 "Maximum number of IPv4 fragment reassembly queue entries"); 151 152 __read_mostly static int maxfragsperpacket; 153 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW, 154 &maxfragsperpacket, 0, 155 "Maximum number of IPv4 fragments allowed per packet"); 156 157 __read_mostly static int ip_sendsourcequench = 0; 158 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW, 159 &ip_sendsourcequench, 0, 160 "Enable the transmission of source quench packets"); 161 162 __read_mostly int ip_do_randomid = 1; 163 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW, 164 &ip_do_randomid, 0, 165 "Assign random ip_id values"); 166 /* 167 * XXX - Setting ip_checkinterface mostly implements the receive side of 168 * the Strong ES model described in RFC 1122, but since the routing table 169 * and transmit implementation do not implement the Strong ES model, 170 * setting this to 1 results in an odd hybrid. 171 * 172 * XXX - ip_checkinterface currently must be disabled if you use ipnat 173 * to translate the destination address to another local interface. 174 * 175 * XXX - ip_checkinterface must be disabled if you add IP aliases 176 * to the loopback interface instead of the interface where the 177 * packets for those addresses are received. 178 */ 179 __read_mostly static int ip_checkinterface = 0; 180 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW, 181 &ip_checkinterface, 0, "Verify packet arrives on correct interface"); 182 183 #ifdef RSS_DEBUG 184 static u_long ip_rehash_count = 0; 185 SYSCTL_ULONG(_net_inet_ip, OID_AUTO, rehash_count, CTLFLAG_RD, 186 &ip_rehash_count, 0, "Number of packets rehashed by IP"); 187 188 static u_long ip_dispatch_fast = 0; 189 SYSCTL_ULONG(_net_inet_ip, OID_AUTO, dispatch_fast_count, CTLFLAG_RD, 190 &ip_dispatch_fast, 0, "Number of packets handled on current CPU"); 191 192 static u_long ip_dispatch_slow = 0; 193 SYSCTL_ULONG(_net_inet_ip, OID_AUTO, dispatch_slow_count, CTLFLAG_RD, 194 &ip_dispatch_slow, 0, "Number of packets messaged to another CPU"); 195 #endif 196 197 #ifdef DIAGNOSTIC 198 static int ipprintfs = 0; 199 #endif 200 201 extern struct domain inetdomain; 202 extern struct protosw inetsw[]; 203 u_char ip_protox[IPPROTO_MAX]; 204 struct in_ifaddrhead in_ifaddrheads[MAXCPU]; /* first inet address */ 205 struct in_ifaddrhashhead *in_ifaddrhashtbls[MAXCPU]; 206 /* inet addr hash table */ 207 __read_mostly u_long in_ifaddrhmask; /* mask for hash table */ 208 209 static struct mbuf *ipforward_mtemp[MAXCPU]; 210 211 struct ip_stats ipstats_percpu[MAXCPU] __cachealign; 212 213 static int 214 sysctl_ipstats(SYSCTL_HANDLER_ARGS) 215 { 216 int cpu, error = 0; 217 218 for (cpu = 0; cpu < netisr_ncpus; ++cpu) { 219 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu], 220 sizeof(struct ip_stats)))) 221 break; 222 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu], 223 sizeof(struct ip_stats)))) 224 break; 225 } 226 227 return (error); 228 } 229 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW), 230 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics"); 231 232 /* Packet reassembly stuff */ 233 #define IPREASS_NHASH_LOG2 6 234 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 235 #define IPREASS_HMASK (IPREASS_NHASH - 1) 236 #define IPREASS_HASH(x,y) \ 237 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 238 239 TAILQ_HEAD(ipqhead, ipq); 240 struct ipfrag_queue { 241 int nipq; 242 volatile int draining; 243 struct netmsg_base timeo_netmsg; 244 struct callout timeo_ch; 245 struct netmsg_base drain_netmsg; 246 struct ipqhead ipq[IPREASS_NHASH]; 247 } __cachealign; 248 249 static struct ipfrag_queue ipfrag_queue_pcpu[MAXCPU]; 250 251 #ifdef IPCTL_DEFMTU 252 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 253 &ip_mtu, 0, "Default MTU"); 254 #endif 255 256 #ifdef IPSTEALTH 257 static int ipstealth = 0; 258 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, ""); 259 #else 260 static const int ipstealth = 0; 261 #endif 262 263 struct mbuf *(*ip_divert_p)(struct mbuf *, int, int); 264 265 struct pfil_head inet_pfil_hook; 266 267 /* 268 * struct ip_srcrt_opt is used to store packet state while it travels 269 * through the stack. 270 * 271 * XXX Note that the code even makes assumptions on the size and 272 * alignment of fields inside struct ip_srcrt so e.g. adding some 273 * fields will break the code. This needs to be fixed. 274 * 275 * We need to save the IP options in case a protocol wants to respond 276 * to an incoming packet over the same route if the packet got here 277 * using IP source routing. This allows connection establishment and 278 * maintenance when the remote end is on a network that is not known 279 * to us. 280 */ 281 struct ip_srcrt { 282 struct in_addr dst; /* final destination */ 283 char nop; /* one NOP to align */ 284 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 285 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 286 }; 287 288 struct ip_srcrt_opt { 289 int ip_nhops; 290 struct ip_srcrt ip_srcrt; 291 }; 292 293 #define IPFRAG_MPIPE_MAX 4096 294 #define MAXIPFRAG_MIN ((IPFRAG_MPIPE_MAX * 2) / 256) 295 296 #define IPFRAG_TIMEO (hz / PR_SLOWHZ) 297 298 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management"); 299 static struct malloc_pipe ipq_mpipe; 300 301 static void save_rte(struct mbuf *, u_char *, struct in_addr); 302 static int ip_dooptions(struct mbuf *m, int, struct sockaddr_in *); 303 static void ip_freef(struct ipfrag_queue *, struct ipqhead *, 304 struct ipq *); 305 static void ip_input_handler(netmsg_t); 306 static void ip_forward_redispatch(struct lwkt_port *port, 307 struct mbuf *m, boolean_t srcrt); 308 309 static void ipfrag_timeo_dispatch(netmsg_t); 310 static void ipfrag_timeo(void *); 311 static void ipfrag_drain_dispatch(netmsg_t); 312 313 /* 314 * IP initialization: fill in IP protocol switch table. 315 * All protocols not implemented in kernel go to raw IP protocol handler. 316 */ 317 void 318 ip_init(void) 319 { 320 struct ipfrag_queue *fragq; 321 struct protosw *pr; 322 int cpu, i; 323 324 /* 325 * Make sure we can handle a reasonable number of fragments but 326 * cap it at IPFRAG_MPIPE_MAX. 327 */ 328 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq), 329 IFQ_MAXLEN, IPFRAG_MPIPE_MAX, 0, NULL, NULL, NULL); 330 331 /* 332 * Make in_ifaddrhead and in_ifaddrhashtbl available on all CPUs, 333 * since they could be accessed by any threads. 334 */ 335 for (cpu = 0; cpu < ncpus; ++cpu) { 336 TAILQ_INIT(&in_ifaddrheads[cpu]); 337 in_ifaddrhashtbls[cpu] = 338 hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask); 339 } 340 341 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 342 if (pr == NULL) 343 panic("ip_init"); 344 for (i = 0; i < IPPROTO_MAX; i++) 345 ip_protox[i] = pr - inetsw; 346 for (pr = inetdomain.dom_protosw; 347 pr < inetdomain.dom_protoswNPROTOSW; pr++) { 348 if (pr->pr_domain->dom_family == PF_INET && pr->pr_protocol) { 349 if (pr->pr_protocol != IPPROTO_RAW) 350 ip_protox[pr->pr_protocol] = pr - inetsw; 351 } 352 } 353 354 inet_pfil_hook.ph_type = PFIL_TYPE_AF; 355 inet_pfil_hook.ph_af = AF_INET; 356 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) { 357 kprintf("%s: WARNING: unable to register pfil hook, " 358 "error %d\n", __func__, i); 359 } 360 361 maxnipq = (nmbclusters / 32) / netisr_ncpus; 362 if (maxnipq < MAXIPFRAG_MIN) 363 maxnipq = MAXIPFRAG_MIN; 364 maxfragsperpacket = 16; 365 366 ip_id = time_second & 0xffff; /* time_second survives reboots */ 367 368 for (cpu = 0; cpu < netisr_ncpus; ++cpu) { 369 /* 370 * Initialize IP statistics counters for each CPU. 371 */ 372 bzero(&ipstats_percpu[cpu], sizeof(struct ip_stats)); 373 374 /* 375 * Preallocate mbuf template for forwarding 376 */ 377 MGETHDR(ipforward_mtemp[cpu], M_WAITOK, MT_DATA); 378 379 /* 380 * Initialize per-cpu ip fragments queues 381 */ 382 fragq = &ipfrag_queue_pcpu[cpu]; 383 for (i = 0; i < IPREASS_NHASH; i++) 384 TAILQ_INIT(&fragq->ipq[i]); 385 386 callout_init_mp(&fragq->timeo_ch); 387 netmsg_init(&fragq->timeo_netmsg, NULL, &netisr_adone_rport, 388 MSGF_PRIORITY, ipfrag_timeo_dispatch); 389 netmsg_init(&fragq->drain_netmsg, NULL, &netisr_adone_rport, 390 MSGF_PRIORITY, ipfrag_drain_dispatch); 391 } 392 393 netisr_register(NETISR_IP, ip_input_handler, ip_hashfn); 394 netisr_register_hashcheck(NETISR_IP, ip_hashcheck); 395 396 for (cpu = 0; cpu < netisr_ncpus; ++cpu) { 397 fragq = &ipfrag_queue_pcpu[cpu]; 398 callout_reset_bycpu(&fragq->timeo_ch, IPFRAG_TIMEO, 399 ipfrag_timeo, NULL, cpu); 400 } 401 402 ip_porthash_trycount = 2 * netisr_ncpus; 403 } 404 405 /* Do transport protocol processing. */ 406 static void 407 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip) 408 { 409 const struct protosw *pr = &inetsw[ip_protox[ip->ip_p]]; 410 411 /* 412 * Switch out to protocol's input routine. 413 */ 414 PR_GET_MPLOCK(pr); 415 pr->pr_input(&m, &hlen, ip->ip_p); 416 PR_REL_MPLOCK(pr); 417 } 418 419 static void 420 transport_processing_handler(netmsg_t msg) 421 { 422 struct netmsg_packet *pmsg = &msg->packet; 423 struct ip *ip; 424 int hlen; 425 426 ip = mtod(pmsg->nm_packet, struct ip *); 427 hlen = pmsg->base.lmsg.u.ms_result; 428 429 transport_processing_oncpu(pmsg->nm_packet, hlen, ip); 430 /* msg was embedded in the mbuf, do not reply! */ 431 } 432 433 static void 434 ip_input_handler(netmsg_t msg) 435 { 436 ip_input(msg->packet.nm_packet); 437 /* msg was embedded in the mbuf, do not reply! */ 438 } 439 440 /* 441 * IP input routine. Checksum and byte swap header. If fragmented 442 * try to reassemble. Process options. Pass to next level. 443 */ 444 void 445 ip_input(struct mbuf *m) 446 { 447 struct ip *ip; 448 struct in_ifaddr *ia = NULL; 449 struct in_ifaddr_container *iac; 450 int hlen, checkif; 451 u_short sum; 452 uint16_t ip_len; 453 struct in_addr pkt_dst; 454 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */ 455 struct in_addr odst; /* original dst address(NAT) */ 456 struct m_tag *mtag; 457 struct sockaddr_in *next_hop = NULL; 458 lwkt_port_t port; 459 460 ASSERT_NETISR_NCPUS(mycpuid); 461 M_ASSERTPKTHDR(m); 462 463 if (m->m_len < sizeof(struct ip)) { 464 kprintf("Issuer to ip_input failed to check IP header atomicy (%d)\n", 465 m->m_len); 466 ipstat.ips_badlen++; 467 goto bad; 468 } 469 #if 0 470 /* length checks already done in ip_hashfn() */ 471 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); 472 #endif 473 474 /* 475 * This routine is called from numerous places which may not have 476 * characterized the packet. 477 */ 478 ip = mtod(m, struct ip *); 479 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) || 480 (ip->ip_off & htons(IP_MF | IP_OFFMASK))) 481 { 482 /* 483 * Force hash recalculation for fragments and multicast 484 * packets; hardware may not do it correctly. 485 * XXX add flag to indicate the hash is from hardware 486 */ 487 m->m_flags &= ~M_HASH; 488 } 489 if ((m->m_flags & M_HASH) == 0) { 490 ip_hashfn(&m, 0); 491 if (m == NULL) 492 return; 493 KKASSERT(m->m_flags & M_HASH); 494 495 if (&curthread->td_msgport != 496 netisr_hashport(m->m_pkthdr.hash)) { 497 netisr_queue(NETISR_IP, m); 498 /* Requeued to other netisr msgport; done */ 499 return; 500 } 501 502 /* mbuf could have been changed */ 503 ip = mtod(m, struct ip *); 504 } 505 506 /* 507 * Pull out certain tags 508 */ 509 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 510 /* Next hop */ 511 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 512 KKASSERT(mtag != NULL); 513 next_hop = m_tag_data(mtag); 514 } 515 516 if (m->m_pkthdr.fw_flags & 517 (DUMMYNET_MBUF_TAGGED | IPFW_MBUF_CONTINUE)) { 518 /* 519 * - Dummynet already filtered this packet. 520 * - This packet was processed by ipfw on another 521 * cpu, and the rest of the ipfw processing should 522 * be carried out on this cpu. 523 */ 524 ip = mtod(m, struct ip *); 525 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 526 goto iphack; 527 } 528 529 ipstat.ips_total++; 530 531 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 532 ipstat.ips_badvers++; 533 goto bad; 534 } 535 536 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 537 /* length checks already done in ip_hashfn() */ 538 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small")); 539 KASSERT(m->m_len >= hlen, ("complete IP header not in one mbuf")); 540 541 /* 127/8 must not appear on wire - RFC1122 */ 542 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 543 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 544 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) { 545 ipstat.ips_badaddr++; 546 goto bad; 547 } 548 } 549 550 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { 551 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 552 } else { 553 if (hlen == sizeof(struct ip)) 554 sum = in_cksum_hdr(ip); 555 else 556 sum = in_cksum(m, hlen); 557 } 558 if (sum != 0) { 559 ipstat.ips_badsum++; 560 goto bad; 561 } 562 563 #ifdef ALTQ 564 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) { 565 /* packet is dropped by traffic conditioner */ 566 return; 567 } 568 #endif 569 /* 570 * Convert fields to host representation. 571 */ 572 ip_len = ntohs(ip->ip_len); 573 574 /* length checks already done in ip_hashfn() */ 575 KASSERT(ip_len >= hlen, ("total length incl header")); 576 KASSERT(m->m_pkthdr.len >= ip_len, ("mbuf too short")); 577 578 /* 579 * Trim mbufs if longer than the IP header would have us expect. 580 */ 581 if (m->m_pkthdr.len > ip_len) { 582 if (m->m_len == m->m_pkthdr.len) { 583 m->m_len = ip_len; 584 m->m_pkthdr.len = ip_len; 585 } else { 586 m_adj(m, ip_len - m->m_pkthdr.len); 587 } 588 } 589 590 /* 591 * IpHack's section. 592 * Right now when no processing on packet has done 593 * and it is still fresh out of network we do our black 594 * deals with it. 595 * - Firewall: deny/allow/divert 596 * - Xlate: translate packet's addr/port (NAT). 597 * - Pipe: pass pkt through dummynet. 598 * - Wrap: fake packet's addr/port <unimpl.> 599 * - Encapsulate: put it in another IP and send out. <unimp.> 600 */ 601 602 iphack: 603 /* 604 * If we've been forwarded from the output side, then 605 * skip the firewall a second time 606 */ 607 if (next_hop != NULL) 608 goto ours; 609 610 /* No pfil hooks */ 611 if (!pfil_has_hooks(&inet_pfil_hook)) { 612 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 613 /* 614 * Strip dummynet tags from stranded packets 615 */ 616 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL); 617 KKASSERT(mtag != NULL); 618 m_tag_delete(m, mtag); 619 m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED; 620 } 621 goto pass; 622 } 623 624 /* 625 * Run through list of hooks for input packets. 626 * 627 * NOTE! If the packet is rewritten pf/ipfw/whoever must 628 * clear M_HASH. 629 */ 630 odst = ip->ip_dst; 631 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN)) 632 return; 633 if (m == NULL) /* consumed by filter */ 634 return; 635 ip = mtod(m, struct ip *); 636 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 637 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr); 638 639 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 640 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 641 KKASSERT(mtag != NULL); 642 next_hop = m_tag_data(mtag); 643 } 644 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) { 645 ip_dn_queue(m); 646 return; 647 } 648 if (m->m_pkthdr.fw_flags & FW_MBUF_REDISPATCH) 649 m->m_pkthdr.fw_flags &= ~FW_MBUF_REDISPATCH; 650 if (m->m_pkthdr.fw_flags & IPFW_MBUF_CONTINUE) { 651 /* ipfw was disabled/unloaded. */ 652 goto bad; 653 } 654 pass: 655 /* 656 * Process options and, if not destined for us, 657 * ship it on. ip_dooptions returns 1 when an 658 * error was detected (causing an icmp message 659 * to be sent and the original packet to be freed). 660 */ 661 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, next_hop)) 662 return; 663 664 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 665 * matter if it is destined to another node, or whether it is 666 * a multicast one, RSVP wants it! and prevents it from being forwarded 667 * anywhere else. Also checks if the rsvp daemon is running before 668 * grabbing the packet. 669 */ 670 if (rsvp_on && ip->ip_p == IPPROTO_RSVP) 671 goto ours; 672 673 /* 674 * Check our list of addresses, to see if the packet is for us. 675 * If we don't have any addresses, assume any unicast packet 676 * we receive might be for us (and let the upper layers deal 677 * with it). 678 */ 679 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) && 680 !(m->m_flags & (M_MCAST | M_BCAST))) 681 { 682 goto ours; 683 } 684 685 /* 686 * Cache the destination address of the packet; this may be 687 * changed by use of 'ipfw fwd'. 688 */ 689 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst; 690 691 /* 692 * Enable a consistency check between the destination address 693 * and the arrival interface for a unicast packet (the RFC 1122 694 * strong ES model) if IP forwarding is disabled and the packet 695 * is not locally generated and the packet is not subject to 696 * 'ipfw fwd'. 697 * 698 * XXX - Checking also should be disabled if the destination 699 * address is ipnat'ed to a different interface. 700 * 701 * XXX - Checking is incompatible with IP aliases added 702 * to the loopback interface instead of the interface where 703 * the packets are received. 704 */ 705 checkif = ip_checkinterface && 706 !ipforwarding && 707 m->m_pkthdr.rcvif != NULL && 708 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) && 709 next_hop == NULL; 710 711 /* 712 * Check for exact addresses in the hash bucket. 713 */ 714 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) { 715 ia = iac->ia; 716 717 /* 718 * If the address matches, verify that the packet 719 * arrived via the correct interface if checking is 720 * enabled. 721 */ 722 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr && 723 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif)) 724 { 725 goto ours; 726 } 727 } 728 ia = NULL; 729 730 /* 731 * Check for broadcast addresses. 732 * 733 * Only accept broadcast packets that arrive via the matching 734 * interface. Reception of forwarded directed broadcasts would 735 * be handled via ip_forward() and ether_output() with the loopback 736 * into the stack for SIMPLEX interfaces handled by ether_output(). 737 */ 738 if (m->m_pkthdr.rcvif != NULL && 739 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 740 struct ifaddr_container *ifac; 741 742 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], 743 ifa_link) { 744 struct ifaddr *ifa = ifac->ifa; 745 746 if (ifa->ifa_addr == NULL) /* shutdown/startup race */ 747 continue; 748 if (ifa->ifa_addr->sa_family != AF_INET) 749 continue; 750 ia = ifatoia(ifa); 751 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 752 pkt_dst.s_addr) 753 goto ours; 754 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr) 755 goto ours; 756 #ifdef BOOTP_COMPAT 757 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 758 goto ours; 759 #endif 760 } 761 } 762 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 763 struct in_multi *inm; 764 765 if (ip_mrouter != NULL) { 766 /* XXX Multicast routing is not MPSAFE yet */ 767 get_mplock(); 768 769 /* 770 * If we are acting as a multicast router, all 771 * incoming multicast packets are passed to the 772 * kernel-level multicast forwarding function. 773 * The packet is returned (relatively) intact; if 774 * ip_mforward() returns a non-zero value, the packet 775 * must be discarded, else it may be accepted below. 776 */ 777 if (ip_mforward != NULL && 778 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) { 779 rel_mplock(); 780 ipstat.ips_cantforward++; 781 m_freem(m); 782 return; 783 } 784 785 rel_mplock(); 786 787 /* 788 * The process-level routing daemon needs to receive 789 * all multicast IGMP packets, whether or not this 790 * host belongs to their destination groups. 791 */ 792 if (ip->ip_p == IPPROTO_IGMP) 793 goto ours; 794 ipstat.ips_forward++; 795 } 796 /* 797 * See if we belong to the destination multicast group on the 798 * arrival interface. 799 */ 800 inm = IN_LOOKUP_MULTI(&ip->ip_dst, m->m_pkthdr.rcvif); 801 if (inm == NULL) { 802 ipstat.ips_notmember++; 803 m_freem(m); 804 return; 805 } 806 goto ours; 807 } 808 if (ip->ip_dst.s_addr == INADDR_BROADCAST) 809 goto ours; 810 if (ip->ip_dst.s_addr == INADDR_ANY) 811 goto ours; 812 813 /* 814 * Not for us; forward if possible and desirable. 815 */ 816 if (!ipforwarding) { 817 ipstat.ips_cantforward++; 818 m_freem(m); 819 } else { 820 ip_forward(m, using_srcrt, next_hop); 821 } 822 return; 823 824 ours: 825 826 /* 827 * IPSTEALTH: Process non-routing options only 828 * if the packet is destined for us. 829 */ 830 if (ipstealth && 831 hlen > sizeof(struct ip) && 832 ip_dooptions(m, 1, next_hop)) 833 { 834 return; 835 } 836 837 /* Count the packet in the ip address stats */ 838 if (ia != NULL) { 839 IFA_STAT_INC(&ia->ia_ifa, ipackets, 1); 840 IFA_STAT_INC(&ia->ia_ifa, ibytes, m->m_pkthdr.len); 841 } 842 843 /* 844 * If offset or IP_MF are set, must reassemble. 845 * Otherwise, nothing need be done. 846 * (We could look in the reassembly queue to see 847 * if the packet was previously fragmented, 848 * but it's not worth the time; just let them time out.) 849 */ 850 if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) { 851 /* 852 * Attempt reassembly; if it succeeds, proceed. ip_reass() 853 * will return a different mbuf. 854 * 855 * NOTE: ip_reass() returns m with M_HASH cleared to force 856 * us to recharacterize the packet. 857 */ 858 m = ip_reass(m); 859 if (m == NULL) 860 return; 861 ip = mtod(m, struct ip *); 862 863 /* Get the header length of the reassembled packet */ 864 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 865 } 866 867 /* 868 * We must forward the packet to the correct protocol thread if 869 * we are not already in it. 870 * 871 * NOTE: ip_len is left in network form. ip_len is not adjusted 872 * further for protocol processing, instead we pass hlen 873 * to the protosw and let it deal with it. 874 */ 875 ipstat.ips_delivered++; 876 877 if ((m->m_flags & M_HASH) == 0) { 878 m = ip_rehashm(m); 879 if (m == NULL) 880 return; 881 ip = mtod(m, struct ip *); 882 } 883 port = netisr_hashport(m->m_pkthdr.hash); 884 885 if (port != &curthread->td_msgport) { 886 ip_transport_redispatch(port, m, hlen); 887 } else { 888 #ifdef RSS_DEBUG 889 atomic_add_long(&ip_dispatch_fast, 1); 890 #endif 891 transport_processing_oncpu(m, hlen, ip); 892 } 893 return; 894 895 bad: 896 m_freem(m); 897 } 898 899 struct mbuf * 900 ip_rehashm(struct mbuf *m) 901 { 902 struct ip *ip = mtod(m, struct ip *); 903 904 #ifdef RSS_DEBUG 905 atomic_add_long(&ip_rehash_count, 1); 906 #endif 907 ip_hashfn(&m, 0); 908 if (m == NULL) 909 return NULL; 910 911 /* 'm' might be changed by ip_hashfn(). */ 912 ip = mtod(m, struct ip *); 913 KASSERT(m->m_flags & M_HASH, ("no hash")); 914 915 return (m); 916 } 917 918 void 919 ip_transport_redispatch(struct lwkt_port *port, struct mbuf *m, int hlen) 920 { 921 struct netmsg_packet *pmsg; 922 923 #ifdef RSS_DEBUG 924 atomic_add_long(&ip_dispatch_slow, 1); 925 #endif 926 927 pmsg = &m->m_hdr.mh_netmsg; 928 netmsg_init(&pmsg->base, NULL, &netisr_apanic_rport, 929 0, transport_processing_handler); 930 pmsg->nm_packet = m; 931 pmsg->base.lmsg.u.ms_result = hlen; 932 lwkt_sendmsg(port, &pmsg->base.lmsg); 933 } 934 935 static void 936 ip_forward_handler(netmsg_t msg) 937 { 938 struct netmsg_forward *fmsg; 939 struct mbuf *m; 940 struct m_tag *mtag; 941 struct sockaddr_in *next_hop = NULL; 942 943 fmsg = &msg->forward; 944 m = fmsg->nm_packet; 945 946 /* Re-extract the next hop if it exists */ 947 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) { 948 /* Next hop */ 949 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 950 KKASSERT(mtag != NULL); 951 next_hop = m_tag_data(mtag); 952 } 953 954 ip_forward(m, fmsg->using_srcrt, next_hop); 955 /* msg was embedded in the mbuf, do not reply! */ 956 } 957 958 static void 959 ip_forward_redispatch(struct lwkt_port *port, struct mbuf *m, boolean_t srcrt) 960 { 961 struct netmsg_forward *fmsg; 962 963 fmsg = &m->m_hdr.mh_fwdmsg; 964 netmsg_init(&fmsg->base, NULL, &netisr_apanic_rport, 965 0, ip_forward_handler); 966 fmsg->nm_packet = m; 967 fmsg->using_srcrt = srcrt; 968 lwkt_sendmsg(port, &fmsg->base.lmsg); 969 } 970 971 /* 972 * Take incoming datagram fragment and try to reassemble it into 973 * whole datagram. If a chain for reassembly of this datagram already 974 * exists, then it is given as fp; otherwise have to make a chain. 975 */ 976 struct mbuf * 977 ip_reass(struct mbuf *m) 978 { 979 struct ipfrag_queue *fragq = &ipfrag_queue_pcpu[mycpuid]; 980 struct ip *ip = mtod(m, struct ip *); 981 struct mbuf *p = NULL, *q, *nq; 982 struct mbuf *n; 983 struct ipq *fp = NULL; 984 struct ipqhead *head; 985 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 986 int i, next; 987 u_short sum; 988 uint16_t ip_off; 989 uint16_t ip_len; 990 991 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */ 992 if (maxnipq == 0 || maxfragsperpacket == 0) { 993 ipstat.ips_fragments++; 994 ipstat.ips_fragdropped++; 995 m_freem(m); 996 return NULL; 997 } 998 999 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 1000 /* 1001 * Look for queue of fragments of this datagram. 1002 */ 1003 head = &fragq->ipq[sum]; 1004 TAILQ_FOREACH(fp, head, ipq_list) { 1005 if (ip->ip_id == fp->ipq_id && 1006 ip->ip_src.s_addr == fp->ipq_src.s_addr && 1007 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 1008 ip->ip_p == fp->ipq_p) 1009 { 1010 goto found; 1011 } 1012 } 1013 1014 fp = NULL; 1015 1016 /* 1017 * Enforce upper bound on number of fragmented packets 1018 * for which we attempt reassembly; 1019 * If maxnipq is -1, accept all fragments without limitation. 1020 */ 1021 if (fragq->nipq > maxnipq && maxnipq > 0) { 1022 /* 1023 * drop something from the tail of the current queue 1024 * before proceeding further 1025 */ 1026 struct ipq *q = TAILQ_LAST(head, ipqhead); 1027 if (q == NULL) { 1028 /* 1029 * The current queue is empty, 1030 * so drop from one of the others. 1031 */ 1032 for (i = 0; i < IPREASS_NHASH; i++) { 1033 struct ipq *r; 1034 1035 r = TAILQ_LAST(&fragq->ipq[i], ipqhead); 1036 if (r) { 1037 ipstat.ips_fragtimeout += r->ipq_nfrags; 1038 ip_freef(fragq, &fragq->ipq[i], r); 1039 break; 1040 } 1041 } 1042 } else { 1043 ipstat.ips_fragtimeout += q->ipq_nfrags; 1044 ip_freef(fragq, head, q); 1045 } 1046 } 1047 found: 1048 /* 1049 * NOTE: ip_len is no longer adjusted to remove the header length. 1050 */ 1051 if (ip->ip_off & htons(IP_MF)) { 1052 /* 1053 * Make sure that fragments have a data length 1054 * that's a non-zero multiple of 8 bytes. The 1055 * IP header itself might be in multiples of 4 1056 * bytes and is discounted. 1057 */ 1058 ip_len = ntohs(ip->ip_len) - hlen; 1059 if (ip_len == 0 || (ip_len & 7) != 0) { 1060 ipstat.ips_toosmall++; /* XXX */ 1061 m_freem(m); 1062 goto done; 1063 } 1064 m->m_flags |= M_FRAG; 1065 } else { 1066 m->m_flags &= ~M_FRAG; 1067 } 1068 1069 ipstat.ips_fragments++; 1070 m->m_pkthdr.header = ip; 1071 1072 /* 1073 * If the hardware has not done csum over this fragment 1074 * then csum_data is not valid at all. 1075 */ 1076 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) 1077 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) 1078 { 1079 m->m_pkthdr.csum_data = 0; 1080 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR); 1081 } 1082 1083 /* 1084 * Presence of header sizes in mbufs would confuse code below. 1085 * Note that ip->ip_len is not modified and retains the header length, 1086 * but local ip_len and fp_len variables remove the header length. 1087 */ 1088 m->m_data += hlen; 1089 m->m_len -= hlen; 1090 1091 /* 1092 * If first fragment to arrive, create a reassembly queue. 1093 */ 1094 if (fp == NULL) { 1095 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL) 1096 goto dropfrag; 1097 TAILQ_INSERT_HEAD(head, fp, ipq_list); 1098 fragq->nipq++; 1099 fp->ipq_nfrags = 1; 1100 fp->ipq_ttl = IPFRAGTTL; 1101 fp->ipq_p = ip->ip_p; 1102 fp->ipq_id = ip->ip_id; 1103 fp->ipq_src = ip->ip_src; 1104 fp->ipq_dst = ip->ip_dst; 1105 fp->ipq_frags = m; 1106 m->m_nextpkt = NULL; 1107 goto inserted; 1108 } 1109 fp->ipq_nfrags++; 1110 1111 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 1112 1113 /* 1114 * Find a segment which begins after this one does. We 1115 * don't have to fully convert the offset field for this 1116 * test. 1117 */ 1118 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1119 if ((ntohs(GETIP(q)->ip_off) & IP_OFFMASK) > 1120 (ntohs(ip->ip_off) & IP_OFFMASK)) 1121 { 1122 break; 1123 } 1124 } 1125 1126 /* 1127 * Drop fragment if it overflows the maximum allowed IP 1128 * packet size. 1129 */ 1130 ip_off = (ntohs(ip->ip_off) & IP_OFFMASK) << 3; 1131 ip_len = ntohs(ip->ip_len); 1132 1133 if (ip_off + ip_len > 65535U) 1134 goto dropfrag; 1135 1136 ip_len -= hlen; 1137 1138 /* 1139 * If there is a preceding segment, it may provide some of 1140 * our data already. If so, drop the data from the incoming 1141 * segment. If it provides all of our data, drop us, otherwise 1142 * stick new segment in the proper place. 1143 * 1144 * If some of the data is dropped from the the preceding 1145 * segment, then it's checksum is invalidated. 1146 */ 1147 1148 if (p) { 1149 uint16_t fp_off; 1150 uint16_t fp_len; 1151 1152 /* 1153 * Calculations in bytes and ip_len/fp_len do not reflect 1154 * the header size. 1155 */ 1156 fp_off = (ntohs(GETIP(p)->ip_off) & IP_OFFMASK) << 3; 1157 fp_len = ntohs(GETIP(p)->ip_len) - 1158 (IP_VHL_HL(GETIP(p)->ip_vhl) << 2); 1159 1160 if (fp_off + fp_len > ip_off) { 1161 i = fp_off + fp_len - ip_off; 1162 if (i >= ip_len) 1163 goto dropfrag; 1164 m_adj(m, i); 1165 m->m_pkthdr.csum_flags = 0; 1166 ip_off = fp_off + fp_len; 1167 ip_len -= i; 1168 1169 /* 1170 * Non-optimal modification of packet content, but 1171 * in this rare case we don't care. 1172 */ 1173 ip->ip_off = htons(ip_off >> 3); 1174 ip->ip_len = htons(ip_len + hlen); 1175 } 1176 m->m_nextpkt = p->m_nextpkt; 1177 p->m_nextpkt = m; 1178 } else { 1179 m->m_nextpkt = fp->ipq_frags; 1180 fp->ipq_frags = m; 1181 } 1182 1183 /* 1184 * Dequeue any later segments that we completely overlap. 1185 * While we overlap succeeding segments trim them or, 1186 * if they are completely covered, dequeue them. 1187 */ 1188 while (q) { 1189 uint16_t fp_off; 1190 uint16_t fp_len; 1191 uint16_t fp_hlen; 1192 1193 fp_off = (ntohs(GETIP(q)->ip_off) & IP_OFFMASK) << 3; 1194 fp_hlen = (IP_VHL_HL(GETIP(q)->ip_vhl) << 2); 1195 fp_len = ntohs(GETIP(q)->ip_len) - fp_hlen; 1196 if (ip_off + ip_len <= fp_off) 1197 break; 1198 i = ip_off + ip_len - fp_off; /* bytes overlapped */ 1199 1200 if (i < fp_len) { 1201 /* 1202 * Non-optimal modification of packet content, but 1203 * in this rare case we don't care. 1204 */ 1205 GETIP(q)->ip_len = htons(fp_len - i + fp_hlen); 1206 GETIP(q)->ip_off = htons((fp_off + i) >> 3); 1207 m_adj(q, i); 1208 q->m_pkthdr.csum_flags = 0; 1209 break; 1210 } 1211 nq = q->m_nextpkt; 1212 m->m_nextpkt = nq; 1213 ipstat.ips_fragdropped++; 1214 fp->ipq_nfrags--; 1215 q->m_nextpkt = NULL; 1216 m_freem(q); 1217 1218 q = nq; 1219 } 1220 1221 inserted: 1222 /* 1223 * Check for complete reassembly and perform frag per packet 1224 * limiting. 1225 * 1226 * Frag limiting is performed here so that the nth frag has 1227 * a chance to complete the packet before we drop the packet. 1228 * As a result, n+1 frags are actually allowed per packet, but 1229 * only n will ever be stored. (n = maxfragsperpacket.) 1230 * 1231 */ 1232 next = 0; 1233 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 1234 uint16_t fp_off; 1235 uint16_t fp_len; 1236 uint16_t fp_hlen; 1237 1238 fp_off = (ntohs(GETIP(q)->ip_off) & IP_OFFMASK) << 3; 1239 fp_hlen = (IP_VHL_HL(GETIP(q)->ip_vhl) << 2); 1240 fp_len = ntohs(GETIP(q)->ip_len) - fp_hlen; 1241 if (fp_off != next) { 1242 if (fp->ipq_nfrags > maxfragsperpacket) { 1243 ipstat.ips_fragdropped += fp->ipq_nfrags; 1244 ip_freef(fragq, head, fp); 1245 } 1246 goto done; 1247 } 1248 next += fp_len; 1249 } 1250 /* Make sure the last packet didn't have the IP_MF flag */ 1251 if (p->m_flags & M_FRAG) { 1252 if (fp->ipq_nfrags > maxfragsperpacket) { 1253 ipstat.ips_fragdropped += fp->ipq_nfrags; 1254 ip_freef(fragq, head, fp); 1255 } 1256 goto done; 1257 } 1258 1259 /* 1260 * Reassembly is complete. Make sure the packet is a sane size. 1261 */ 1262 q = fp->ipq_frags; 1263 ip = GETIP(q); 1264 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 1265 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 1266 ipstat.ips_toolong++; 1267 ipstat.ips_fragdropped += fp->ipq_nfrags; 1268 ip_freef(fragq, head, fp); 1269 goto done; 1270 } 1271 1272 /* 1273 * Concatenate fragments. 1274 */ 1275 m = q; 1276 n = m->m_next; 1277 m->m_next = NULL; 1278 m_cat(m, n); 1279 nq = q->m_nextpkt; 1280 q->m_nextpkt = NULL; 1281 for (q = nq; q != NULL; q = nq) { 1282 nq = q->m_nextpkt; 1283 q->m_nextpkt = NULL; 1284 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; 1285 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; 1286 m_cat(m, q); 1287 } 1288 1289 /* 1290 * Clean up the 1's complement checksum. Carry over 16 bits must 1291 * be added back. This assumes no more then 65535 packet fragments 1292 * were reassembled. A second carry can also occur (but not a third). 1293 */ 1294 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + 1295 (m->m_pkthdr.csum_data >> 16); 1296 if (m->m_pkthdr.csum_data > 0xFFFF) 1297 m->m_pkthdr.csum_data -= 0xFFFF; 1298 1299 /* 1300 * Create header for new ip packet by modifying the header of the 1301 * first packet. Dequeue and discard the fragment reassembly header. 1302 * Make the header visible. Set the offset to 0 and keep only the 1303 * DF flag from the first packet's ip_off field. 1304 * 1305 * Note that ip_len includes the header length. 1306 */ 1307 ip->ip_len = htons(next + hlen); 1308 ip->ip_src = fp->ipq_src; 1309 ip->ip_dst = fp->ipq_dst; 1310 ip->ip_off &= htons(IP_DF); 1311 TAILQ_REMOVE(head, fp, ipq_list); 1312 fragq->nipq--; 1313 mpipe_free(&ipq_mpipe, fp); 1314 1315 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 1316 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 1317 /* some debugging cruft by sklower, below, will go away soon */ 1318 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 1319 int plen = 0; 1320 1321 for (n = m; n; n = n->m_next) 1322 plen += n->m_len; 1323 m->m_pkthdr.len = plen; 1324 } 1325 1326 /* 1327 * Reassembly complete, return the next protocol. 1328 * 1329 * Be sure to clear M_HASH to force the packet 1330 * to be re-characterized. 1331 * 1332 * Clear M_FRAG, we are no longer a fragment. 1333 */ 1334 m->m_flags &= ~(M_HASH | M_FRAG); 1335 1336 ipstat.ips_reassembled++; 1337 return (m); 1338 1339 dropfrag: 1340 ipstat.ips_fragdropped++; 1341 if (fp != NULL) 1342 fp->ipq_nfrags--; 1343 m_freem(m); 1344 done: 1345 return (NULL); 1346 1347 #undef GETIP 1348 } 1349 1350 /* 1351 * Free a fragment reassembly header and all 1352 * associated datagrams. 1353 */ 1354 static void 1355 ip_freef(struct ipfrag_queue *fragq, struct ipqhead *fhp, struct ipq *fp) 1356 { 1357 struct mbuf *q; 1358 1359 /* 1360 * Remove first to protect against blocking 1361 */ 1362 TAILQ_REMOVE(fhp, fp, ipq_list); 1363 1364 /* 1365 * Clean out at our leisure 1366 */ 1367 while (fp->ipq_frags) { 1368 q = fp->ipq_frags; 1369 fp->ipq_frags = q->m_nextpkt; 1370 q->m_nextpkt = NULL; 1371 m_freem(q); 1372 } 1373 mpipe_free(&ipq_mpipe, fp); 1374 fragq->nipq--; 1375 } 1376 1377 /* 1378 * If a timer expires on a reassembly queue, discard it. 1379 */ 1380 static void 1381 ipfrag_timeo_dispatch(netmsg_t nmsg) 1382 { 1383 struct ipfrag_queue *fragq = &ipfrag_queue_pcpu[mycpuid]; 1384 struct ipq *fp, *fp_temp; 1385 struct ipqhead *head; 1386 int i; 1387 1388 crit_enter(); 1389 netisr_replymsg(&nmsg->base, 0); /* reply ASAP */ 1390 crit_exit(); 1391 1392 if (fragq->nipq == 0) 1393 goto done; 1394 1395 for (i = 0; i < IPREASS_NHASH; i++) { 1396 head = &fragq->ipq[i]; 1397 TAILQ_FOREACH_MUTABLE(fp, head, ipq_list, fp_temp) { 1398 if (--fp->ipq_ttl == 0) { 1399 ipstat.ips_fragtimeout += fp->ipq_nfrags; 1400 ip_freef(fragq, head, fp); 1401 } 1402 } 1403 } 1404 /* 1405 * If we are over the maximum number of fragments 1406 * (due to the limit being lowered), drain off 1407 * enough to get down to the new limit. 1408 */ 1409 if (maxnipq >= 0 && fragq->nipq > maxnipq) { 1410 for (i = 0; i < IPREASS_NHASH; i++) { 1411 head = &fragq->ipq[i]; 1412 while (fragq->nipq > maxnipq && !TAILQ_EMPTY(head)) { 1413 ipstat.ips_fragdropped += 1414 TAILQ_FIRST(head)->ipq_nfrags; 1415 ip_freef(fragq, head, TAILQ_FIRST(head)); 1416 } 1417 } 1418 } 1419 done: 1420 callout_reset(&fragq->timeo_ch, IPFRAG_TIMEO, ipfrag_timeo, NULL); 1421 } 1422 1423 static void 1424 ipfrag_timeo(void *dummy __unused) 1425 { 1426 struct netmsg_base *msg = &ipfrag_queue_pcpu[mycpuid].timeo_netmsg; 1427 1428 crit_enter(); 1429 if (msg->lmsg.ms_flags & MSGF_DONE) 1430 netisr_sendmsg_oncpu(msg); 1431 crit_exit(); 1432 } 1433 1434 /* 1435 * Drain off all datagram fragments. 1436 */ 1437 static void 1438 ipfrag_drain_oncpu(struct ipfrag_queue *fragq) 1439 { 1440 struct ipqhead *head; 1441 int i; 1442 1443 for (i = 0; i < IPREASS_NHASH; i++) { 1444 head = &fragq->ipq[i]; 1445 while (!TAILQ_EMPTY(head)) { 1446 ipstat.ips_fragdropped += TAILQ_FIRST(head)->ipq_nfrags; 1447 ip_freef(fragq, head, TAILQ_FIRST(head)); 1448 } 1449 } 1450 } 1451 1452 static void 1453 ipfrag_drain_dispatch(netmsg_t nmsg) 1454 { 1455 struct ipfrag_queue *fragq = &ipfrag_queue_pcpu[mycpuid]; 1456 1457 crit_enter(); 1458 lwkt_replymsg(&nmsg->lmsg, 0); /* reply ASAP */ 1459 crit_exit(); 1460 1461 ipfrag_drain_oncpu(fragq); 1462 fragq->draining = 0; 1463 } 1464 1465 static void 1466 ipfrag_drain_ipi(void *arg __unused) 1467 { 1468 int cpu = mycpuid; 1469 struct lwkt_msg *msg = &ipfrag_queue_pcpu[cpu].drain_netmsg.lmsg; 1470 1471 crit_enter(); 1472 if (msg->ms_flags & MSGF_DONE) 1473 lwkt_sendmsg_oncpu(netisr_cpuport(cpu), msg); 1474 crit_exit(); 1475 } 1476 1477 static void 1478 ipfrag_drain(void) 1479 { 1480 cpumask_t mask; 1481 int cpu; 1482 1483 CPUMASK_ASSBMASK(mask, netisr_ncpus); 1484 CPUMASK_ANDMASK(mask, smp_active_mask); 1485 1486 if (IN_NETISR_NCPUS(mycpuid)) { 1487 ipfrag_drain_oncpu(&ipfrag_queue_pcpu[mycpuid]); 1488 CPUMASK_NANDBIT(mask, mycpuid); 1489 } 1490 1491 for (cpu = 0; cpu < netisr_ncpus; ++cpu) { 1492 struct ipfrag_queue *fragq = &ipfrag_queue_pcpu[cpu]; 1493 1494 if (!CPUMASK_TESTBIT(mask, cpu)) 1495 continue; 1496 1497 if (fragq->nipq == 0 || fragq->draining) { 1498 /* No fragments or is draining; skip this cpu. */ 1499 CPUMASK_NANDBIT(mask, cpu); 1500 continue; 1501 } 1502 fragq->draining = 1; 1503 } 1504 1505 if (CPUMASK_TESTNZERO(mask)) 1506 lwkt_send_ipiq_mask(mask, ipfrag_drain_ipi, NULL); 1507 } 1508 1509 void 1510 ip_drain(void) 1511 { 1512 ipfrag_drain(); 1513 in_rtqdrain(); 1514 } 1515 1516 /* 1517 * Do option processing on a datagram, 1518 * possibly discarding it if bad options are encountered, 1519 * or forwarding it if source-routed. 1520 * The pass argument is used when operating in the IPSTEALTH 1521 * mode to tell what options to process: 1522 * [LS]SRR (pass 0) or the others (pass 1). 1523 * The reason for as many as two passes is that when doing IPSTEALTH, 1524 * non-routing options should be processed only if the packet is for us. 1525 * Returns 1 if packet has been forwarded/freed, 1526 * 0 if the packet should be processed further. 1527 */ 1528 static int 1529 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop) 1530 { 1531 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET }; 1532 struct ip *ip = mtod(m, struct ip *); 1533 u_char *cp; 1534 struct in_ifaddr *ia; 1535 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB; 1536 boolean_t forward = FALSE; 1537 struct in_addr *sin, dst; 1538 n_time ntime; 1539 1540 dst = ip->ip_dst; 1541 cp = (u_char *)(ip + 1); 1542 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1543 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1544 opt = cp[IPOPT_OPTVAL]; 1545 if (opt == IPOPT_EOL) 1546 break; 1547 if (opt == IPOPT_NOP) 1548 optlen = 1; 1549 else { 1550 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1551 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1552 goto bad; 1553 } 1554 optlen = cp[IPOPT_OLEN]; 1555 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1556 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1557 goto bad; 1558 } 1559 } 1560 switch (opt) { 1561 1562 default: 1563 break; 1564 1565 /* 1566 * Source routing with record. 1567 * Find interface with current destination address. 1568 * If none on this machine then drop if strictly routed, 1569 * or do nothing if loosely routed. 1570 * Record interface address and bring up next address 1571 * component. If strictly routed make sure next 1572 * address is on directly accessible net. 1573 */ 1574 case IPOPT_LSRR: 1575 case IPOPT_SSRR: 1576 if (ipstealth && pass > 0) 1577 break; 1578 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1579 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1580 goto bad; 1581 } 1582 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1583 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1584 goto bad; 1585 } 1586 ipaddr.sin_addr = ip->ip_dst; 1587 ia = (struct in_ifaddr *) 1588 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1589 if (ia == NULL) { 1590 if (opt == IPOPT_SSRR) { 1591 type = ICMP_UNREACH; 1592 code = ICMP_UNREACH_SRCFAIL; 1593 goto bad; 1594 } 1595 if (!ip_dosourceroute) 1596 goto nosourcerouting; 1597 /* 1598 * Loose routing, and not at next destination 1599 * yet; nothing to do except forward. 1600 */ 1601 break; 1602 } 1603 off--; /* 0 origin */ 1604 if (off > optlen - (int)sizeof(struct in_addr)) { 1605 /* 1606 * End of source route. Should be for us. 1607 */ 1608 if (!ip_acceptsourceroute) 1609 goto nosourcerouting; 1610 save_rte(m, cp, ip->ip_src); 1611 break; 1612 } 1613 if (ipstealth) 1614 goto dropit; 1615 if (!ip_dosourceroute) { 1616 if (ipforwarding) { 1617 char sbuf[INET_ADDRSTRLEN]; 1618 char dbuf[INET_ADDRSTRLEN]; 1619 1620 /* 1621 * Acting as a router, so generate ICMP 1622 */ 1623 nosourcerouting: 1624 log(LOG_WARNING, 1625 "attempted source route from %s to %s\n", 1626 kinet_ntoa(ip->ip_src, sbuf), 1627 kinet_ntoa(ip->ip_dst, dbuf)); 1628 type = ICMP_UNREACH; 1629 code = ICMP_UNREACH_SRCFAIL; 1630 goto bad; 1631 } else { 1632 /* 1633 * Not acting as a router, 1634 * so silently drop. 1635 */ 1636 dropit: 1637 ipstat.ips_cantforward++; 1638 m_freem(m); 1639 return (1); 1640 } 1641 } 1642 1643 /* 1644 * locate outgoing interface 1645 */ 1646 memcpy(&ipaddr.sin_addr, cp + off, 1647 sizeof ipaddr.sin_addr); 1648 1649 if (opt == IPOPT_SSRR) { 1650 #define INA struct in_ifaddr * 1651 #define SA struct sockaddr * 1652 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) 1653 == NULL) 1654 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1655 } else { 1656 ia = ip_rtaddr(ipaddr.sin_addr, NULL); 1657 } 1658 if (ia == NULL) { 1659 type = ICMP_UNREACH; 1660 code = ICMP_UNREACH_SRCFAIL; 1661 goto bad; 1662 } 1663 ip->ip_dst = ipaddr.sin_addr; 1664 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1665 sizeof(struct in_addr)); 1666 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1667 /* 1668 * Let ip_intr's mcast routing check handle mcast pkts 1669 */ 1670 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1671 break; 1672 1673 case IPOPT_RR: 1674 if (ipstealth && pass == 0) 1675 break; 1676 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1677 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1678 goto bad; 1679 } 1680 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1681 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1682 goto bad; 1683 } 1684 /* 1685 * If no space remains, ignore. 1686 */ 1687 off--; /* 0 origin */ 1688 if (off > optlen - (int)sizeof(struct in_addr)) 1689 break; 1690 memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1691 sizeof ipaddr.sin_addr); 1692 /* 1693 * locate outgoing interface; if we're the destination, 1694 * use the incoming interface (should be same). 1695 */ 1696 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 1697 (ia = ip_rtaddr(ipaddr.sin_addr, NULL)) == NULL) { 1698 type = ICMP_UNREACH; 1699 code = ICMP_UNREACH_HOST; 1700 goto bad; 1701 } 1702 memcpy(cp + off, &IA_SIN(ia)->sin_addr, 1703 sizeof(struct in_addr)); 1704 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1705 break; 1706 1707 case IPOPT_TS: 1708 if (ipstealth && pass == 0) 1709 break; 1710 code = cp - (u_char *)ip; 1711 if (optlen < 4 || optlen > 40) { 1712 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1713 goto bad; 1714 } 1715 if ((off = cp[IPOPT_OFFSET]) < 5) { 1716 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1717 goto bad; 1718 } 1719 if (off > optlen - (int)sizeof(int32_t)) { 1720 cp[IPOPT_OFFSET + 1] += (1 << 4); 1721 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 1722 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1723 goto bad; 1724 } 1725 break; 1726 } 1727 off--; /* 0 origin */ 1728 sin = (struct in_addr *)(cp + off); 1729 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 1730 1731 case IPOPT_TS_TSONLY: 1732 break; 1733 1734 case IPOPT_TS_TSANDADDR: 1735 if (off + sizeof(n_time) + 1736 sizeof(struct in_addr) > optlen) { 1737 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1738 goto bad; 1739 } 1740 ipaddr.sin_addr = dst; 1741 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1742 m->m_pkthdr.rcvif); 1743 if (ia == NULL) 1744 continue; 1745 memcpy(sin, &IA_SIN(ia)->sin_addr, 1746 sizeof(struct in_addr)); 1747 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1748 off += sizeof(struct in_addr); 1749 break; 1750 1751 case IPOPT_TS_PRESPEC: 1752 if (off + sizeof(n_time) + 1753 sizeof(struct in_addr) > optlen) { 1754 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1755 goto bad; 1756 } 1757 memcpy(&ipaddr.sin_addr, sin, 1758 sizeof(struct in_addr)); 1759 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 1760 continue; 1761 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1762 off += sizeof(struct in_addr); 1763 break; 1764 1765 default: 1766 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 1767 goto bad; 1768 } 1769 ntime = iptime(); 1770 memcpy(cp + off, &ntime, sizeof(n_time)); 1771 cp[IPOPT_OFFSET] += sizeof(n_time); 1772 } 1773 } 1774 if (forward && ipforwarding) { 1775 ip_forward(m, TRUE, next_hop); 1776 return (1); 1777 } 1778 return (0); 1779 bad: 1780 icmp_error(m, type, code, 0, 0); 1781 ipstat.ips_badoptions++; 1782 return (1); 1783 } 1784 1785 /* 1786 * Given address of next destination (final or next hop), 1787 * return internet address info of interface to be used to get there. 1788 */ 1789 struct in_ifaddr * 1790 ip_rtaddr(struct in_addr dst, struct route *ro0) 1791 { 1792 struct route sro, *ro; 1793 struct sockaddr_in *sin; 1794 struct in_ifaddr *ia; 1795 1796 if (ro0 != NULL) { 1797 ro = ro0; 1798 } else { 1799 bzero(&sro, sizeof(sro)); 1800 ro = &sro; 1801 } 1802 1803 sin = (struct sockaddr_in *)&ro->ro_dst; 1804 1805 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) { 1806 if (ro->ro_rt != NULL) { 1807 RTFREE(ro->ro_rt); 1808 ro->ro_rt = NULL; 1809 } 1810 sin->sin_family = AF_INET; 1811 sin->sin_len = sizeof *sin; 1812 sin->sin_addr = dst; 1813 rtalloc_ign(ro, RTF_PRCLONING); 1814 } 1815 1816 if (ro->ro_rt == NULL) 1817 return (NULL); 1818 1819 ia = ifatoia(ro->ro_rt->rt_ifa); 1820 1821 if (ro == &sro) 1822 RTFREE(ro->ro_rt); 1823 return ia; 1824 } 1825 1826 /* 1827 * Save incoming source route for use in replies, 1828 * to be picked up later by ip_srcroute if the receiver is interested. 1829 */ 1830 static void 1831 save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 1832 { 1833 struct m_tag *mtag; 1834 struct ip_srcrt_opt *opt; 1835 unsigned olen; 1836 1837 mtag = m_tag_get(PACKET_TAG_IPSRCRT, sizeof(*opt), M_NOWAIT); 1838 if (mtag == NULL) 1839 return; 1840 opt = m_tag_data(mtag); 1841 1842 olen = option[IPOPT_OLEN]; 1843 #ifdef DIAGNOSTIC 1844 if (ipprintfs) 1845 kprintf("save_rte: olen %d\n", olen); 1846 #endif 1847 if (olen > sizeof(opt->ip_srcrt) - (1 + sizeof(dst))) { 1848 m_tag_free(mtag); 1849 return; 1850 } 1851 bcopy(option, opt->ip_srcrt.srcopt, olen); 1852 opt->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1853 opt->ip_srcrt.dst = dst; 1854 m_tag_prepend(m, mtag); 1855 } 1856 1857 /* 1858 * Retrieve incoming source route for use in replies, 1859 * in the same form used by setsockopt. 1860 * The first hop is placed before the options, will be removed later. 1861 */ 1862 struct mbuf * 1863 ip_srcroute(struct mbuf *m0) 1864 { 1865 struct in_addr *p, *q; 1866 struct mbuf *m; 1867 struct m_tag *mtag; 1868 struct ip_srcrt_opt *opt; 1869 1870 if (m0 == NULL) 1871 return NULL; 1872 1873 mtag = m_tag_find(m0, PACKET_TAG_IPSRCRT, NULL); 1874 if (mtag == NULL) 1875 return NULL; 1876 opt = m_tag_data(mtag); 1877 1878 if (opt->ip_nhops == 0) 1879 return (NULL); 1880 m = m_get(M_NOWAIT, MT_HEADER); 1881 if (m == NULL) 1882 return (NULL); 1883 1884 #define OPTSIZ (sizeof(opt->ip_srcrt.nop) + sizeof(opt->ip_srcrt.srcopt)) 1885 1886 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1887 m->m_len = opt->ip_nhops * sizeof(struct in_addr) + 1888 sizeof(struct in_addr) + OPTSIZ; 1889 #ifdef DIAGNOSTIC 1890 if (ipprintfs) { 1891 kprintf("ip_srcroute: nhops %d mlen %d", 1892 opt->ip_nhops, m->m_len); 1893 } 1894 #endif 1895 1896 /* 1897 * First save first hop for return route 1898 */ 1899 p = &opt->ip_srcrt.route[opt->ip_nhops - 1]; 1900 *(mtod(m, struct in_addr *)) = *p--; 1901 #ifdef DIAGNOSTIC 1902 if (ipprintfs) 1903 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1904 #endif 1905 1906 /* 1907 * Copy option fields and padding (nop) to mbuf. 1908 */ 1909 opt->ip_srcrt.nop = IPOPT_NOP; 1910 opt->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1911 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &opt->ip_srcrt.nop, 1912 OPTSIZ); 1913 q = (struct in_addr *)(mtod(m, caddr_t) + 1914 sizeof(struct in_addr) + OPTSIZ); 1915 #undef OPTSIZ 1916 /* 1917 * Record return path as an IP source route, 1918 * reversing the path (pointers are now aligned). 1919 */ 1920 while (p >= opt->ip_srcrt.route) { 1921 #ifdef DIAGNOSTIC 1922 if (ipprintfs) 1923 kprintf(" %x", ntohl(q->s_addr)); 1924 #endif 1925 *q++ = *p--; 1926 } 1927 /* 1928 * Last hop goes to final destination. 1929 */ 1930 *q = opt->ip_srcrt.dst; 1931 m_tag_delete(m0, mtag); 1932 #ifdef DIAGNOSTIC 1933 if (ipprintfs) 1934 kprintf(" %x\n", ntohl(q->s_addr)); 1935 #endif 1936 return (m); 1937 } 1938 1939 /* 1940 * Strip out IP options. 1941 */ 1942 void 1943 ip_stripoptions(struct mbuf *m) 1944 { 1945 int datalen; 1946 struct ip *ip = mtod(m, struct ip *); 1947 caddr_t opts; 1948 int optlen; 1949 1950 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); 1951 opts = (caddr_t)(ip + 1); 1952 datalen = m->m_len - (sizeof(struct ip) + optlen); 1953 bcopy(opts + optlen, opts, datalen); 1954 m->m_len -= optlen; 1955 if (m->m_flags & M_PKTHDR) 1956 m->m_pkthdr.len -= optlen; 1957 /* leave ip version intact */ 1958 ip->ip_len = htons(ntohs(ip->ip_len) - optlen); 1959 ip->ip_vhl = IP_MAKE_VHL(IP_VHL_V(ip->ip_vhl), sizeof(struct ip) >> 2); 1960 } 1961 1962 u_char inetctlerrmap[PRC_NCMDS] = { 1963 0, 0, 0, 0, 1964 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1965 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1966 EMSGSIZE, EHOSTUNREACH, 0, 0, 1967 0, 0, 0, 0, 1968 ENOPROTOOPT, ECONNREFUSED 1969 }; 1970 1971 /* 1972 * Forward a packet. If some error occurs return the sender 1973 * an icmp packet. Note we can't always generate a meaningful 1974 * icmp message because icmp doesn't have a large enough repertoire 1975 * of codes and types. 1976 * 1977 * If not forwarding, just drop the packet. This could be confusing 1978 * if ipforwarding was zero but some routing protocol was advancing 1979 * us as a gateway to somewhere. However, we must let the routing 1980 * protocol deal with that. 1981 * 1982 * The using_srcrt parameter indicates whether the packet is being forwarded 1983 * via a source route. 1984 */ 1985 void 1986 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop) 1987 { 1988 struct ip *ip = mtod(m, struct ip *); 1989 struct rtentry *rt; 1990 struct route fwd_ro; 1991 int error, type = 0, code = 0, destmtu = 0; 1992 struct mbuf *mcopy, *mtemp = NULL; 1993 n_long dest; 1994 struct in_addr pkt_dst; 1995 1996 dest = INADDR_ANY; 1997 /* 1998 * Cache the destination address of the packet; this may be 1999 * changed by use of 'ipfw fwd'. 2000 */ 2001 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst; 2002 2003 #ifdef DIAGNOSTIC 2004 if (ipprintfs) 2005 kprintf("forward: src %x dst %x ttl %x\n", 2006 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl); 2007 #endif 2008 2009 if ((m->m_flags & M_HASH) == 0) { 2010 lwkt_port_t port; 2011 2012 m = ip_rehashm(m); 2013 if (m == NULL) 2014 return; 2015 2016 port = netisr_hashport(m->m_pkthdr.hash); 2017 2018 if (port != &curthread->td_msgport) { 2019 ip_forward_redispatch(port, m, using_srcrt); 2020 /* Requeued to other msgport; done */ 2021 return; 2022 } 2023 } 2024 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) { 2025 ipstat.ips_cantforward++; 2026 m_freem(m); 2027 return; 2028 } 2029 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) { 2030 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 2031 return; 2032 } 2033 2034 bzero(&fwd_ro, sizeof(fwd_ro)); 2035 ip_rtaddr(pkt_dst, &fwd_ro); 2036 if (fwd_ro.ro_rt == NULL) { 2037 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 2038 return; 2039 } 2040 rt = fwd_ro.ro_rt; 2041 2042 if (curthread->td_type == TD_TYPE_NETISR) { 2043 /* 2044 * Save the IP header and at most 8 bytes of the payload, 2045 * in case we need to generate an ICMP message to the src. 2046 */ 2047 mtemp = ipforward_mtemp[mycpuid]; 2048 KASSERT((mtemp->m_flags & M_EXT) == 0 && 2049 mtemp->m_data == mtemp->m_pktdat && 2050 m_tag_first(mtemp) == NULL, 2051 ("ip_forward invalid mtemp1")); 2052 2053 if (!m_dup_pkthdr(mtemp, m, M_NOWAIT)) { 2054 /* 2055 * It's probably ok if the pkthdr dup fails (because 2056 * the deep copy of the tag chain failed), but for now 2057 * be conservative and just discard the copy since 2058 * code below may some day want the tags. 2059 */ 2060 mtemp = NULL; 2061 } else { 2062 mtemp->m_type = m->m_type; 2063 mtemp->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8, 2064 (int)ntohs(ip->ip_len)); 2065 mtemp->m_pkthdr.len = mtemp->m_len; 2066 m_copydata(m, 0, mtemp->m_len, mtod(mtemp, caddr_t)); 2067 } 2068 } 2069 2070 if (!ipstealth) 2071 ip->ip_ttl -= IPTTLDEC; 2072 2073 /* 2074 * If forwarding packet using same interface that it came in on, 2075 * perhaps should send a redirect to sender to shortcut a hop. 2076 * Only send redirect if source is sending directly to us, 2077 * and if packet was not source routed (or has any options). 2078 * Also, don't send redirect if forwarding using a default route 2079 * or a route modified by a redirect. 2080 */ 2081 if (rt->rt_ifp == m->m_pkthdr.rcvif && 2082 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) && 2083 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY && 2084 ipsendredirects && !using_srcrt && next_hop == NULL) { 2085 u_long src = ntohl(ip->ip_src.s_addr); 2086 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa; 2087 2088 if (rt_ifa != NULL && 2089 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) { 2090 if (rt->rt_flags & RTF_GATEWAY) 2091 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 2092 else 2093 dest = pkt_dst.s_addr; 2094 /* 2095 * Router requirements says to only send 2096 * host redirects. 2097 */ 2098 type = ICMP_REDIRECT; 2099 code = ICMP_REDIRECT_HOST; 2100 #ifdef DIAGNOSTIC 2101 if (ipprintfs) 2102 kprintf("redirect (%d) to %x\n", code, dest); 2103 #endif 2104 } 2105 } 2106 2107 error = ip_output(m, NULL, &fwd_ro, IP_FORWARDING, NULL, NULL); 2108 if (error == 0) { 2109 ipstat.ips_forward++; 2110 if (type == 0) { 2111 if (mtemp) 2112 ipflow_create(&fwd_ro, mtemp); 2113 goto done; 2114 } 2115 ipstat.ips_redirectsent++; 2116 } else { 2117 ipstat.ips_cantforward++; 2118 } 2119 2120 if (mtemp == NULL) 2121 goto done; 2122 2123 /* 2124 * Errors that do not require generating ICMP message 2125 */ 2126 switch (error) { 2127 case ENOBUFS: 2128 /* 2129 * A router should not generate ICMP_SOURCEQUENCH as 2130 * required in RFC1812 Requirements for IP Version 4 Routers. 2131 * Source quench could be a big problem under DoS attacks, 2132 * or if the underlying interface is rate-limited. 2133 * Those who need source quench packets may re-enable them 2134 * via the net.inet.ip.sendsourcequench sysctl. 2135 */ 2136 if (!ip_sendsourcequench) 2137 goto done; 2138 break; 2139 2140 case EACCES: /* ipfw denied packet */ 2141 goto done; 2142 } 2143 2144 KASSERT((mtemp->m_flags & M_EXT) == 0 && 2145 mtemp->m_data == mtemp->m_pktdat, 2146 ("ip_forward invalid mtemp2")); 2147 mcopy = m_copym(mtemp, 0, mtemp->m_len, M_NOWAIT); 2148 if (mcopy == NULL) 2149 goto done; 2150 2151 /* 2152 * Send ICMP message. 2153 */ 2154 switch (error) { 2155 case 0: /* forwarded, but need redirect */ 2156 /* type, code set above */ 2157 break; 2158 2159 case ENETUNREACH: /* shouldn't happen, checked above */ 2160 case EHOSTUNREACH: 2161 case ENETDOWN: 2162 case EHOSTDOWN: 2163 default: 2164 type = ICMP_UNREACH; 2165 code = ICMP_UNREACH_HOST; 2166 break; 2167 2168 case EMSGSIZE: 2169 type = ICMP_UNREACH; 2170 code = ICMP_UNREACH_NEEDFRAG; 2171 if (fwd_ro.ro_rt != NULL) 2172 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu; 2173 ipstat.ips_cantfrag++; 2174 break; 2175 2176 case ENOBUFS: 2177 type = ICMP_SOURCEQUENCH; 2178 code = 0; 2179 break; 2180 2181 case EACCES: /* ipfw denied packet */ 2182 panic("ip_forward EACCES should not reach"); 2183 } 2184 icmp_error(mcopy, type, code, dest, destmtu); 2185 done: 2186 if (mtemp != NULL) 2187 m_tag_delete_chain(mtemp); 2188 if (fwd_ro.ro_rt != NULL) 2189 RTFREE(fwd_ro.ro_rt); 2190 } 2191 2192 void 2193 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 2194 struct mbuf *m) 2195 { 2196 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 2197 struct timeval tv; 2198 2199 microtime(&tv); 2200 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 2201 SCM_TIMESTAMP, SOL_SOCKET); 2202 if (*mp) 2203 mp = &(*mp)->m_next; 2204 } 2205 if (inp->inp_flags & INP_RECVDSTADDR) { 2206 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 2207 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 2208 if (*mp) 2209 mp = &(*mp)->m_next; 2210 } 2211 if (inp->inp_flags & INP_RECVTTL) { 2212 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 2213 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 2214 if (*mp) 2215 mp = &(*mp)->m_next; 2216 } 2217 if (inp->inp_flags & INP_RECVTOS) { 2218 *mp = sbcreatecontrol((caddr_t) &ip->ip_tos, 2219 sizeof(u_char), IP_RECVTOS, IPPROTO_IP); 2220 if (*mp) 2221 mp = &(*mp)->m_next; 2222 } 2223 #ifdef notyet 2224 /* XXX 2225 * Moving these out of udp_input() made them even more broken 2226 * than they already were. 2227 */ 2228 /* options were tossed already */ 2229 if (inp->inp_flags & INP_RECVOPTS) { 2230 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 2231 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 2232 if (*mp) 2233 mp = &(*mp)->m_next; 2234 } 2235 /* ip_srcroute doesn't do what we want here, need to fix */ 2236 if (inp->inp_flags & INP_RECVRETOPTS) { 2237 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m), 2238 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 2239 if (*mp) 2240 mp = &(*mp)->m_next; 2241 } 2242 #endif 2243 if (inp->inp_flags & INP_RECVIF) { 2244 struct ifnet *ifp; 2245 struct sdlbuf { 2246 struct sockaddr_dl sdl; 2247 u_char pad[32]; 2248 } sdlbuf; 2249 struct sockaddr_dl *sdp; 2250 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 2251 2252 if (((ifp = m->m_pkthdr.rcvif)) && 2253 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) { 2254 sdp = IF_LLSOCKADDR(ifp); 2255 /* 2256 * Change our mind and don't try copy. 2257 */ 2258 if ((sdp->sdl_family != AF_LINK) || 2259 (sdp->sdl_len > sizeof(sdlbuf))) { 2260 goto makedummy; 2261 } 2262 bcopy(sdp, sdl2, sdp->sdl_len); 2263 } else { 2264 makedummy: 2265 sdl2->sdl_len = 2266 offsetof(struct sockaddr_dl, sdl_data[0]); 2267 sdl2->sdl_family = AF_LINK; 2268 sdl2->sdl_index = 0; 2269 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 2270 } 2271 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 2272 IP_RECVIF, IPPROTO_IP); 2273 if (*mp) 2274 mp = &(*mp)->m_next; 2275 } 2276 } 2277 2278 /* 2279 * XXX these routines are called from the upper part of the kernel. 2280 * 2281 * They could also be moved to ip_mroute.c, since all the RSVP 2282 * handling is done there already. 2283 */ 2284 int 2285 ip_rsvp_init(struct socket *so) 2286 { 2287 if (so->so_type != SOCK_RAW || 2288 so->so_proto->pr_protocol != IPPROTO_RSVP) 2289 return EOPNOTSUPP; 2290 2291 if (ip_rsvpd != NULL) 2292 return EADDRINUSE; 2293 2294 ip_rsvpd = so; 2295 /* 2296 * This may seem silly, but we need to be sure we don't over-increment 2297 * the RSVP counter, in case something slips up. 2298 */ 2299 if (!ip_rsvp_on) { 2300 ip_rsvp_on = 1; 2301 rsvp_on++; 2302 } 2303 2304 return 0; 2305 } 2306 2307 int 2308 ip_rsvp_done(void) 2309 { 2310 ip_rsvpd = NULL; 2311 /* 2312 * This may seem silly, but we need to be sure we don't over-decrement 2313 * the RSVP counter, in case something slips up. 2314 */ 2315 if (ip_rsvp_on) { 2316 ip_rsvp_on = 0; 2317 rsvp_on--; 2318 } 2319 return 0; 2320 } 2321 2322 int 2323 rsvp_input(struct mbuf **mp, int *offp, int proto) 2324 { 2325 struct mbuf *m = *mp; 2326 2327 *mp = NULL; 2328 2329 if (rsvp_input_p) { /* call the real one if loaded */ 2330 *mp = m; 2331 rsvp_input_p(mp, offp, proto); 2332 return(IPPROTO_DONE); 2333 } 2334 2335 /* Can still get packets with rsvp_on = 0 if there is a local member 2336 * of the group to which the RSVP packet is addressed. But in this 2337 * case we want to throw the packet away. 2338 */ 2339 2340 if (!rsvp_on) { 2341 m_freem(m); 2342 return(IPPROTO_DONE); 2343 } 2344 2345 if (ip_rsvpd != NULL) { 2346 *mp = m; 2347 rip_input(mp, offp, proto); 2348 return(IPPROTO_DONE); 2349 } 2350 /* Drop the packet */ 2351 m_freem(m); 2352 return(IPPROTO_DONE); 2353 } 2354