1 /* $OpenBSD: ip_input.c,v 1.160 2008/06/08 13:58:09 thib Exp $ */ 2 /* $NetBSD: ip_input.c,v 1.30 1996/03/16 23:53:58 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1988, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 33 */ 34 35 #include "pf.h" 36 #include "carp.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/mbuf.h> 41 #include <sys/domain.h> 42 #include <sys/protosw.h> 43 #include <sys/socket.h> 44 #include <sys/socketvar.h> 45 #include <sys/syslog.h> 46 #include <sys/sysctl.h> 47 #include <sys/pool.h> 48 49 #include <net/if.h> 50 #include <net/if_dl.h> 51 #include <net/route.h> 52 53 #include <netinet/in.h> 54 #include <netinet/in_systm.h> 55 #include <netinet/if_ether.h> 56 #include <netinet/ip.h> 57 #include <netinet/in_pcb.h> 58 #include <netinet/in_var.h> 59 #include <netinet/ip_var.h> 60 #include <netinet/ip_icmp.h> 61 62 #if NPF > 0 63 #include <net/pfvar.h> 64 #endif 65 66 #ifdef MROUTING 67 #include <netinet/ip_mroute.h> 68 #endif 69 70 #ifdef IPSEC 71 #include <netinet/ip_ipsp.h> 72 #endif /* IPSEC */ 73 74 #if NCARP > 0 75 #include <net/if_types.h> 76 #include <netinet/ip_carp.h> 77 #endif 78 79 #define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */ 80 81 struct ipqhead ipq; 82 83 int encdebug = 0; 84 int ipsec_keep_invalid = IPSEC_DEFAULT_EMBRYONIC_SA_TIMEOUT; 85 int ipsec_require_pfs = IPSEC_DEFAULT_PFS; 86 int ipsec_soft_allocations = IPSEC_DEFAULT_SOFT_ALLOCATIONS; 87 int ipsec_exp_allocations = IPSEC_DEFAULT_EXP_ALLOCATIONS; 88 int ipsec_soft_bytes = IPSEC_DEFAULT_SOFT_BYTES; 89 int ipsec_exp_bytes = IPSEC_DEFAULT_EXP_BYTES; 90 int ipsec_soft_timeout = IPSEC_DEFAULT_SOFT_TIMEOUT; 91 int ipsec_exp_timeout = IPSEC_DEFAULT_EXP_TIMEOUT; 92 int ipsec_soft_first_use = IPSEC_DEFAULT_SOFT_FIRST_USE; 93 int ipsec_exp_first_use = IPSEC_DEFAULT_EXP_FIRST_USE; 94 int ipsec_expire_acquire = IPSEC_DEFAULT_EXPIRE_ACQUIRE; 95 char ipsec_def_enc[20]; 96 char ipsec_def_auth[20]; 97 char ipsec_def_comp[20]; 98 99 /* values controllable via sysctl */ 100 int ipforwarding = 0; 101 int ipmforwarding = 0; 102 int ipmultipath = 0; 103 int ipsendredirects = 1; 104 int ip_dosourceroute = 0; 105 int ip_defttl = IPDEFTTL; 106 int ip_mtudisc = 1; 107 u_int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 108 int ip_directedbcast = 0; 109 #ifdef DIAGNOSTIC 110 int ipprintfs = 0; 111 #endif 112 113 struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 114 115 int ipsec_auth_default_level = IPSEC_AUTH_LEVEL_DEFAULT; 116 int ipsec_esp_trans_default_level = IPSEC_ESP_TRANS_LEVEL_DEFAULT; 117 int ipsec_esp_network_default_level = IPSEC_ESP_NETWORK_LEVEL_DEFAULT; 118 int ipsec_ipcomp_default_level = IPSEC_IPCOMP_LEVEL_DEFAULT; 119 120 /* Keep track of memory used for reassembly */ 121 int ip_maxqueue = 300; 122 int ip_frags = 0; 123 124 /* from in_pcb.c */ 125 extern int ipport_firstauto; 126 extern int ipport_lastauto; 127 extern int ipport_hifirstauto; 128 extern int ipport_hilastauto; 129 extern struct baddynamicports baddynamicports; 130 131 int *ipctl_vars[IPCTL_MAXID] = IPCTL_VARS; 132 133 extern struct domain inetdomain; 134 extern struct protosw inetsw[]; 135 u_char ip_protox[IPPROTO_MAX]; 136 int ipqmaxlen = IFQ_MAXLEN; 137 struct in_ifaddrhead in_ifaddr; 138 struct ifqueue ipintrq; 139 140 struct pool ipqent_pool; 141 struct pool ipq_pool; 142 143 struct ipstat ipstat; 144 145 char * 146 inet_ntoa(ina) 147 struct in_addr ina; 148 { 149 static char buf[4*sizeof "123"]; 150 unsigned char *ucp = (unsigned char *)&ina; 151 152 snprintf(buf, sizeof buf, "%d.%d.%d.%d", 153 ucp[0] & 0xff, ucp[1] & 0xff, 154 ucp[2] & 0xff, ucp[3] & 0xff); 155 return (buf); 156 } 157 158 /* 159 * We need to save the IP options in case a protocol wants to respond 160 * to an incoming packet over the same route if the packet got here 161 * using IP source routing. This allows connection establishment and 162 * maintenance when the remote end is on a network that is not known 163 * to us. 164 */ 165 int ip_nhops = 0; 166 static struct ip_srcrt { 167 struct in_addr dst; /* final destination */ 168 char nop; /* one NOP to align */ 169 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 170 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 171 } ip_srcrt; 172 173 void save_rte(u_char *, struct in_addr); 174 int ip_weadvertise(u_int32_t); 175 176 /* 177 * IP initialization: fill in IP protocol switch table. 178 * All protocols not implemented in kernel go to raw IP protocol handler. 179 */ 180 void 181 ip_init() 182 { 183 struct protosw *pr; 184 int i; 185 const u_int16_t defbaddynamicports_tcp[] = DEFBADDYNAMICPORTS_TCP; 186 const u_int16_t defbaddynamicports_udp[] = DEFBADDYNAMICPORTS_UDP; 187 188 pool_init(&ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl", 189 NULL); 190 pool_init(&ipq_pool, sizeof(struct ipq), 0, 0, 0, "ipqpl", 191 NULL); 192 193 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 194 if (pr == 0) 195 panic("ip_init"); 196 for (i = 0; i < IPPROTO_MAX; i++) 197 ip_protox[i] = pr - inetsw; 198 for (pr = inetdomain.dom_protosw; 199 pr < inetdomain.dom_protoswNPROTOSW; pr++) 200 if (pr->pr_domain->dom_family == PF_INET && 201 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 202 ip_protox[pr->pr_protocol] = pr - inetsw; 203 LIST_INIT(&ipq); 204 ipintrq.ifq_maxlen = ipqmaxlen; 205 TAILQ_INIT(&in_ifaddr); 206 if (ip_mtudisc != 0) 207 ip_mtudisc_timeout_q = 208 rt_timer_queue_create(ip_mtudisc_timeout); 209 210 /* Fill in list of ports not to allocate dynamically. */ 211 bzero((void *)&baddynamicports, sizeof(baddynamicports)); 212 for (i = 0; defbaddynamicports_tcp[i] != 0; i++) 213 DP_SET(baddynamicports.tcp, defbaddynamicports_tcp[i]); 214 for (i = 0; defbaddynamicports_udp[i] != 0; i++) 215 DP_SET(baddynamicports.udp, defbaddynamicports_udp[i]); 216 217 strlcpy(ipsec_def_enc, IPSEC_DEFAULT_DEF_ENC, sizeof(ipsec_def_enc)); 218 strlcpy(ipsec_def_auth, IPSEC_DEFAULT_DEF_AUTH, sizeof(ipsec_def_auth)); 219 strlcpy(ipsec_def_comp, IPSEC_DEFAULT_DEF_COMP, sizeof(ipsec_def_comp)); 220 } 221 222 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 223 struct route ipforward_rt; 224 int ipforward_rtableid; 225 226 void 227 ipintr() 228 { 229 struct mbuf *m; 230 int s; 231 232 for (;;) { 233 /* 234 * Get next datagram off input queue and get IP header 235 * in first mbuf. 236 */ 237 s = splnet(); 238 IF_DEQUEUE(&ipintrq, m); 239 splx(s); 240 if (m == NULL) 241 return; 242 #ifdef DIAGNOSTIC 243 if ((m->m_flags & M_PKTHDR) == 0) 244 panic("ipintr no HDR"); 245 #endif 246 ipv4_input(m); 247 } 248 } 249 250 /* 251 * Ip input routine. Checksum and byte swap header. If fragmented 252 * try to reassemble. Process options. Pass to next level. 253 */ 254 void 255 ipv4_input(m) 256 struct mbuf *m; 257 { 258 struct ip *ip; 259 struct ipq *fp; 260 struct in_ifaddr *ia; 261 struct ipqent *ipqe; 262 int hlen, mff, len; 263 in_addr_t pfrdr = 0; 264 #ifdef IPSEC 265 int error, s; 266 struct tdb *tdb; 267 struct tdb_ident *tdbi; 268 struct m_tag *mtag; 269 #endif /* IPSEC */ 270 271 /* 272 * If no IP addresses have been set yet but the interfaces 273 * are receiving, can't do anything with incoming packets yet. 274 */ 275 if (TAILQ_EMPTY(&in_ifaddr)) 276 goto bad; 277 ipstat.ips_total++; 278 if (m->m_len < sizeof (struct ip) && 279 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 280 ipstat.ips_toosmall++; 281 return; 282 } 283 ip = mtod(m, struct ip *); 284 if (ip->ip_v != IPVERSION) { 285 ipstat.ips_badvers++; 286 goto bad; 287 } 288 hlen = ip->ip_hl << 2; 289 if (hlen < sizeof(struct ip)) { /* minimum header length */ 290 ipstat.ips_badhlen++; 291 goto bad; 292 } 293 if (hlen > m->m_len) { 294 if ((m = m_pullup(m, hlen)) == NULL) { 295 ipstat.ips_badhlen++; 296 return; 297 } 298 ip = mtod(m, struct ip *); 299 } 300 301 /* 127/8 must not appear on wire - RFC1122 */ 302 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 303 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 304 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 305 ipstat.ips_badaddr++; 306 goto bad; 307 } 308 } 309 310 if ((m->m_pkthdr.csum_flags & M_IPV4_CSUM_IN_OK) == 0) { 311 if (m->m_pkthdr.csum_flags & M_IPV4_CSUM_IN_BAD) { 312 ipstat.ips_inhwcsum++; 313 ipstat.ips_badsum++; 314 goto bad; 315 } 316 317 if (in_cksum(m, hlen) != 0) { 318 ipstat.ips_badsum++; 319 goto bad; 320 } 321 } else { 322 m->m_pkthdr.csum_flags &= ~M_IPV4_CSUM_IN_OK; 323 ipstat.ips_inhwcsum++; 324 } 325 326 /* Retrieve the packet length. */ 327 len = ntohs(ip->ip_len); 328 329 /* 330 * Convert fields to host representation. 331 */ 332 if (len < hlen) { 333 ipstat.ips_badlen++; 334 goto bad; 335 } 336 337 /* 338 * Check that the amount of data in the buffers 339 * is at least as much as the IP header would have us expect. 340 * Trim mbufs if longer than we expect. 341 * Drop packet if shorter than we expect. 342 */ 343 if (m->m_pkthdr.len < len) { 344 ipstat.ips_tooshort++; 345 goto bad; 346 } 347 if (m->m_pkthdr.len > len) { 348 if (m->m_len == m->m_pkthdr.len) { 349 m->m_len = len; 350 m->m_pkthdr.len = len; 351 } else 352 m_adj(m, len - m->m_pkthdr.len); 353 } 354 355 #if NCARP > 0 356 if (m->m_pkthdr.rcvif->if_type == IFT_CARP && 357 ip->ip_p != IPPROTO_ICMP && carp_lsdrop(m, AF_INET, 358 &ip->ip_src.s_addr, &ip->ip_dst.s_addr)) 359 goto bad; 360 #endif 361 362 #if NPF > 0 363 /* 364 * Packet filter 365 */ 366 pfrdr = ip->ip_dst.s_addr; 367 if (pf_test(PF_IN, m->m_pkthdr.rcvif, &m, NULL) != PF_PASS) 368 goto bad; 369 if (m == NULL) 370 return; 371 372 ip = mtod(m, struct ip *); 373 hlen = ip->ip_hl << 2; 374 pfrdr = (pfrdr != ip->ip_dst.s_addr); 375 #endif 376 377 /* 378 * Process options and, if not destined for us, 379 * ship it on. ip_dooptions returns 1 when an 380 * error was detected (causing an icmp message 381 * to be sent and the original packet to be freed). 382 */ 383 ip_nhops = 0; /* for source routed packets */ 384 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 385 return; 386 } 387 388 /* 389 * Check our list of addresses, to see if the packet is for us. 390 */ 391 if ((ia = in_iawithaddr(ip->ip_dst, m)) != NULL && 392 (ia->ia_ifp->if_flags & IFF_UP)) 393 goto ours; 394 395 if (m->m_pkthdr.pf.flags & PF_TAG_DIVERTED) 396 goto ours; 397 398 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 399 struct in_multi *inm; 400 #ifdef MROUTING 401 extern struct socket *ip_mrouter; 402 403 if (m->m_flags & M_EXT) { 404 if ((m = m_pullup(m, hlen)) == NULL) { 405 ipstat.ips_toosmall++; 406 return; 407 } 408 ip = mtod(m, struct ip *); 409 } 410 if (ipmforwarding && ip_mrouter) { 411 /* 412 * If we are acting as a multicast router, all 413 * incoming multicast packets are passed to the 414 * kernel-level multicast forwarding function. 415 * The packet is returned (relatively) intact; if 416 * ip_mforward() returns a non-zero value, the packet 417 * must be discarded, else it may be accepted below. 418 * 419 * (The IP ident field is put in the same byte order 420 * as expected when ip_mforward() is called from 421 * ip_output().) 422 */ 423 if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) { 424 ipstat.ips_cantforward++; 425 m_freem(m); 426 return; 427 } 428 429 /* 430 * The process-level routing daemon needs to receive 431 * all multicast IGMP packets, whether or not this 432 * host belongs to their destination groups. 433 */ 434 if (ip->ip_p == IPPROTO_IGMP) 435 goto ours; 436 ipstat.ips_forward++; 437 } 438 #endif 439 /* 440 * See if we belong to the destination multicast group on the 441 * arrival interface. 442 */ 443 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 444 if (inm == NULL) { 445 ipstat.ips_notmember++; 446 if (!IN_LOCAL_GROUP(ip->ip_dst.s_addr)) 447 ipstat.ips_cantforward++; 448 m_freem(m); 449 return; 450 } 451 goto ours; 452 } 453 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 454 ip->ip_dst.s_addr == INADDR_ANY) 455 goto ours; 456 457 #if NCARP > 0 458 if (m->m_pkthdr.rcvif->if_type == IFT_CARP && 459 ip->ip_p == IPPROTO_ICMP && carp_lsdrop(m, AF_INET, 460 &ip->ip_src.s_addr, &ip->ip_dst.s_addr)) 461 goto bad; 462 #endif 463 /* 464 * Not for us; forward if possible and desirable. 465 */ 466 if (ipforwarding == 0) { 467 ipstat.ips_cantforward++; 468 m_freem(m); 469 return; 470 } 471 #ifdef IPSEC 472 if (ipsec_in_use) { 473 /* 474 * IPsec policy check for forwarded packets. Look at 475 * inner-most IPsec SA used. 476 */ 477 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 478 s = splnet(); 479 if (mtag != NULL) { 480 tdbi = (struct tdb_ident *)(mtag + 1); 481 tdb = gettdb(tdbi->spi, &tdbi->dst, tdbi->proto); 482 } else 483 tdb = NULL; 484 ipsp_spd_lookup(m, AF_INET, hlen, &error, 485 IPSP_DIRECTION_IN, tdb, NULL); 486 splx(s); 487 488 /* Error or otherwise drop-packet indication */ 489 if (error) { 490 ipstat.ips_cantforward++; 491 m_freem(m); 492 return; 493 } 494 495 /* 496 * Fall through, forward packet. Outbound IPsec policy 497 * checking will occur in ip_output(). 498 */ 499 } 500 #endif /* IPSEC */ 501 502 ip_forward(m, pfrdr); 503 return; 504 505 ours: 506 /* 507 * If offset or IP_MF are set, must reassemble. 508 * Otherwise, nothing need be done. 509 * (We could look in the reassembly queue to see 510 * if the packet was previously fragmented, 511 * but it's not worth the time; just let them time out.) 512 */ 513 if (ip->ip_off &~ htons(IP_DF | IP_RF)) { 514 if (m->m_flags & M_EXT) { /* XXX */ 515 if ((m = m_pullup(m, hlen)) == NULL) { 516 ipstat.ips_toosmall++; 517 return; 518 } 519 ip = mtod(m, struct ip *); 520 } 521 522 /* 523 * Look for queue of fragments 524 * of this datagram. 525 */ 526 LIST_FOREACH(fp, &ipq, ipq_q) 527 if (ip->ip_id == fp->ipq_id && 528 ip->ip_src.s_addr == fp->ipq_src.s_addr && 529 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 530 ip->ip_p == fp->ipq_p) 531 goto found; 532 fp = 0; 533 found: 534 535 /* 536 * Adjust ip_len to not reflect header, 537 * set ipqe_mff if more fragments are expected, 538 * convert offset of this to bytes. 539 */ 540 ip->ip_len = htons(ntohs(ip->ip_len) - hlen); 541 mff = (ip->ip_off & htons(IP_MF)) != 0; 542 if (mff) { 543 /* 544 * Make sure that fragments have a data length 545 * that's a non-zero multiple of 8 bytes. 546 */ 547 if (ntohs(ip->ip_len) == 0 || 548 (ntohs(ip->ip_len) & 0x7) != 0) { 549 ipstat.ips_badfrags++; 550 goto bad; 551 } 552 } 553 ip->ip_off = htons(ntohs(ip->ip_off) << 3); 554 555 /* 556 * If datagram marked as having more fragments 557 * or if this is not the first fragment, 558 * attempt reassembly; if it succeeds, proceed. 559 */ 560 if (mff || ip->ip_off) { 561 ipstat.ips_fragments++; 562 if (ip_frags + 1 > ip_maxqueue) { 563 ip_flush(); 564 ipstat.ips_rcvmemdrop++; 565 goto bad; 566 } 567 568 ipqe = pool_get(&ipqent_pool, PR_NOWAIT); 569 if (ipqe == NULL) { 570 ipstat.ips_rcvmemdrop++; 571 goto bad; 572 } 573 ip_frags++; 574 ipqe->ipqe_mff = mff; 575 ipqe->ipqe_m = m; 576 ipqe->ipqe_ip = ip; 577 m = ip_reass(ipqe, fp); 578 if (m == 0) { 579 return; 580 } 581 ipstat.ips_reassembled++; 582 ip = mtod(m, struct ip *); 583 hlen = ip->ip_hl << 2; 584 ip->ip_len = htons(ntohs(ip->ip_len) + hlen); 585 } else 586 if (fp) 587 ip_freef(fp); 588 } 589 590 #ifdef IPSEC 591 if (!ipsec_in_use) 592 goto skipipsec; 593 594 /* 595 * If it's a protected packet for us, skip the policy check. 596 * That's because we really only care about the properties of 597 * the protected packet, and not the intermediate versions. 598 * While this is not the most paranoid setting, it allows 599 * some flexibility in handling nested tunnels (in setting up 600 * the policies). 601 */ 602 if ((ip->ip_p == IPPROTO_ESP) || (ip->ip_p == IPPROTO_AH) || 603 (ip->ip_p == IPPROTO_IPCOMP)) 604 goto skipipsec; 605 606 /* 607 * If the protected packet was tunneled, then we need to 608 * verify the protected packet's information, not the 609 * external headers. Thus, skip the policy lookup for the 610 * external packet, and keep the IPsec information linked on 611 * the packet header (the encapsulation routines know how 612 * to deal with that). 613 */ 614 if ((ip->ip_p == IPPROTO_IPIP) || (ip->ip_p == IPPROTO_IPV6)) 615 goto skipipsec; 616 617 /* 618 * If the protected packet is TCP or UDP, we'll do the 619 * policy check in the respective input routine, so we can 620 * check for bypass sockets. 621 */ 622 if ((ip->ip_p == IPPROTO_TCP) || (ip->ip_p == IPPROTO_UDP)) 623 goto skipipsec; 624 625 /* 626 * IPsec policy check for local-delivery packets. Look at the 627 * inner-most SA that protected the packet. This is in fact 628 * a bit too restrictive (it could end up causing packets to 629 * be dropped that semantically follow the policy, e.g., in 630 * certain SA-bundle configurations); but the alternative is 631 * very complicated (and requires keeping track of what 632 * kinds of tunneling headers have been seen in-between the 633 * IPsec headers), and I don't think we lose much functionality 634 * that's needed in the real world (who uses bundles anyway ?). 635 */ 636 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 637 s = splnet(); 638 if (mtag) { 639 tdbi = (struct tdb_ident *)(mtag + 1); 640 tdb = gettdb(tdbi->spi, &tdbi->dst, tdbi->proto); 641 } else 642 tdb = NULL; 643 ipsp_spd_lookup(m, AF_INET, hlen, &error, IPSP_DIRECTION_IN, 644 tdb, NULL); 645 splx(s); 646 647 /* Error or otherwise drop-packet indication. */ 648 if (error) { 649 ipstat.ips_cantforward++; 650 m_freem(m); 651 return; 652 } 653 654 skipipsec: 655 /* Otherwise, just fall through and deliver the packet */ 656 #endif /* IPSEC */ 657 658 /* 659 * Switch out to protocol's input routine. 660 */ 661 ipstat.ips_delivered++; 662 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, NULL, 0); 663 return; 664 bad: 665 m_freem(m); 666 } 667 668 struct in_ifaddr * 669 in_iawithaddr(ina, m) 670 struct in_addr ina; 671 struct mbuf *m; 672 { 673 struct in_ifaddr *ia; 674 675 TAILQ_FOREACH(ia, &in_ifaddr, ia_list) { 676 if ((ina.s_addr == ia->ia_addr.sin_addr.s_addr) || 677 ((ia->ia_ifp->if_flags & (IFF_LOOPBACK|IFF_LINK1)) == 678 (IFF_LOOPBACK|IFF_LINK1) && 679 ia->ia_subnet == (ina.s_addr & ia->ia_subnetmask))) 680 return ia; 681 if (((ip_directedbcast == 0) || (m && ip_directedbcast && 682 ia->ia_ifp == m->m_pkthdr.rcvif)) && 683 (ia->ia_ifp->if_flags & IFF_BROADCAST)) { 684 if (ina.s_addr == ia->ia_broadaddr.sin_addr.s_addr || 685 ina.s_addr == ia->ia_netbroadcast.s_addr || 686 /* 687 * Look for all-0's host part (old broadcast addr), 688 * either for subnet or net. 689 */ 690 ina.s_addr == ia->ia_subnet || 691 ina.s_addr == ia->ia_net) { 692 /* Make sure M_BCAST is set */ 693 if (m) 694 m->m_flags |= M_BCAST; 695 return ia; 696 } 697 } 698 } 699 700 return NULL; 701 } 702 703 /* 704 * Take incoming datagram fragment and try to 705 * reassemble it into whole datagram. If a chain for 706 * reassembly of this datagram already exists, then it 707 * is given as fp; otherwise have to make a chain. 708 */ 709 struct mbuf * 710 ip_reass(ipqe, fp) 711 struct ipqent *ipqe; 712 struct ipq *fp; 713 { 714 struct mbuf *m = ipqe->ipqe_m; 715 struct ipqent *nq, *p, *q; 716 struct ip *ip; 717 struct mbuf *t; 718 int hlen = ipqe->ipqe_ip->ip_hl << 2; 719 int i, next; 720 u_int8_t ecn, ecn0; 721 722 /* 723 * Presence of header sizes in mbufs 724 * would confuse code below. 725 */ 726 m->m_data += hlen; 727 m->m_len -= hlen; 728 729 /* 730 * If first fragment to arrive, create a reassembly queue. 731 */ 732 if (fp == NULL) { 733 fp = pool_get(&ipq_pool, PR_NOWAIT); 734 if (fp == NULL) 735 goto dropfrag; 736 LIST_INSERT_HEAD(&ipq, fp, ipq_q); 737 fp->ipq_ttl = IPFRAGTTL; 738 fp->ipq_p = ipqe->ipqe_ip->ip_p; 739 fp->ipq_id = ipqe->ipqe_ip->ip_id; 740 LIST_INIT(&fp->ipq_fragq); 741 fp->ipq_src = ipqe->ipqe_ip->ip_src; 742 fp->ipq_dst = ipqe->ipqe_ip->ip_dst; 743 p = NULL; 744 goto insert; 745 } 746 747 /* 748 * Handle ECN by comparing this segment with the first one; 749 * if CE is set, do not lose CE. 750 * drop if CE and not-ECT are mixed for the same packet. 751 */ 752 ecn = ipqe->ipqe_ip->ip_tos & IPTOS_ECN_MASK; 753 ecn0 = LIST_FIRST(&fp->ipq_fragq)->ipqe_ip->ip_tos & IPTOS_ECN_MASK; 754 if (ecn == IPTOS_ECN_CE) { 755 if (ecn0 == IPTOS_ECN_NOTECT) 756 goto dropfrag; 757 if (ecn0 != IPTOS_ECN_CE) 758 LIST_FIRST(&fp->ipq_fragq)->ipqe_ip->ip_tos |= IPTOS_ECN_CE; 759 } 760 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 761 goto dropfrag; 762 763 /* 764 * Find a segment which begins after this one does. 765 */ 766 for (p = NULL, q = LIST_FIRST(&fp->ipq_fragq); 767 q != LIST_END(&fp->ipq_fragq); p = q, q = LIST_NEXT(q, ipqe_q)) 768 if (ntohs(q->ipqe_ip->ip_off) > ntohs(ipqe->ipqe_ip->ip_off)) 769 break; 770 771 /* 772 * If there is a preceding segment, it may provide some of 773 * our data already. If so, drop the data from the incoming 774 * segment. If it provides all of our data, drop us. 775 */ 776 if (p != NULL) { 777 i = ntohs(p->ipqe_ip->ip_off) + ntohs(p->ipqe_ip->ip_len) - 778 ntohs(ipqe->ipqe_ip->ip_off); 779 if (i > 0) { 780 if (i >= ntohs(ipqe->ipqe_ip->ip_len)) 781 goto dropfrag; 782 m_adj(ipqe->ipqe_m, i); 783 ipqe->ipqe_ip->ip_off = 784 htons(ntohs(ipqe->ipqe_ip->ip_off) + i); 785 ipqe->ipqe_ip->ip_len = 786 htons(ntohs(ipqe->ipqe_ip->ip_len) - i); 787 } 788 } 789 790 /* 791 * While we overlap succeeding segments trim them or, 792 * if they are completely covered, dequeue them. 793 */ 794 for (; q != NULL && 795 ntohs(ipqe->ipqe_ip->ip_off) + ntohs(ipqe->ipqe_ip->ip_len) > 796 ntohs(q->ipqe_ip->ip_off); q = nq) { 797 i = (ntohs(ipqe->ipqe_ip->ip_off) + 798 ntohs(ipqe->ipqe_ip->ip_len)) - ntohs(q->ipqe_ip->ip_off); 799 if (i < ntohs(q->ipqe_ip->ip_len)) { 800 q->ipqe_ip->ip_len = 801 htons(ntohs(q->ipqe_ip->ip_len) - i); 802 q->ipqe_ip->ip_off = 803 htons(ntohs(q->ipqe_ip->ip_off) + i); 804 m_adj(q->ipqe_m, i); 805 break; 806 } 807 nq = LIST_NEXT(q, ipqe_q); 808 m_freem(q->ipqe_m); 809 LIST_REMOVE(q, ipqe_q); 810 pool_put(&ipqent_pool, q); 811 ip_frags--; 812 } 813 814 insert: 815 /* 816 * Stick new segment in its place; 817 * check for complete reassembly. 818 */ 819 if (p == NULL) { 820 LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); 821 } else { 822 LIST_INSERT_AFTER(p, ipqe, ipqe_q); 823 } 824 next = 0; 825 for (p = NULL, q = LIST_FIRST(&fp->ipq_fragq); 826 q != LIST_END(&fp->ipq_fragq); p = q, q = LIST_NEXT(q, ipqe_q)) { 827 if (ntohs(q->ipqe_ip->ip_off) != next) 828 return (0); 829 next += ntohs(q->ipqe_ip->ip_len); 830 } 831 if (p->ipqe_mff) 832 return (0); 833 834 /* 835 * Reassembly is complete. Check for a bogus message size and 836 * concatenate fragments. 837 */ 838 q = LIST_FIRST(&fp->ipq_fragq); 839 ip = q->ipqe_ip; 840 if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) { 841 ipstat.ips_toolong++; 842 ip_freef(fp); 843 return (0); 844 } 845 m = q->ipqe_m; 846 t = m->m_next; 847 m->m_next = 0; 848 m_cat(m, t); 849 nq = LIST_NEXT(q, ipqe_q); 850 pool_put(&ipqent_pool, q); 851 ip_frags--; 852 for (q = nq; q != NULL; q = nq) { 853 t = q->ipqe_m; 854 nq = LIST_NEXT(q, ipqe_q); 855 pool_put(&ipqent_pool, q); 856 ip_frags--; 857 m_cat(m, t); 858 } 859 860 /* 861 * Create header for new ip packet by 862 * modifying header of first packet; 863 * dequeue and discard fragment reassembly header. 864 * Make header visible. 865 */ 866 ip->ip_len = htons(next); 867 ip->ip_src = fp->ipq_src; 868 ip->ip_dst = fp->ipq_dst; 869 LIST_REMOVE(fp, ipq_q); 870 pool_put(&ipq_pool, fp); 871 m->m_len += (ip->ip_hl << 2); 872 m->m_data -= (ip->ip_hl << 2); 873 /* some debugging cruft by sklower, below, will go away soon */ 874 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 875 int plen = 0; 876 for (t = m; t; t = t->m_next) 877 plen += t->m_len; 878 m->m_pkthdr.len = plen; 879 } 880 return (m); 881 882 dropfrag: 883 ipstat.ips_fragdropped++; 884 m_freem(m); 885 pool_put(&ipqent_pool, ipqe); 886 ip_frags--; 887 return (0); 888 } 889 890 /* 891 * Free a fragment reassembly header and all 892 * associated datagrams. 893 */ 894 void 895 ip_freef(fp) 896 struct ipq *fp; 897 { 898 struct ipqent *q, *p; 899 900 for (q = LIST_FIRST(&fp->ipq_fragq); q != LIST_END(&fp->ipq_fragq); 901 q = p) { 902 p = LIST_NEXT(q, ipqe_q); 903 m_freem(q->ipqe_m); 904 LIST_REMOVE(q, ipqe_q); 905 pool_put(&ipqent_pool, q); 906 ip_frags--; 907 } 908 LIST_REMOVE(fp, ipq_q); 909 pool_put(&ipq_pool, fp); 910 } 911 912 /* 913 * IP timer processing; 914 * if a timer expires on a reassembly queue, discard it. 915 * clear the forwarding cache, there might be a better route. 916 */ 917 void 918 ip_slowtimo() 919 { 920 struct ipq *fp, *nfp; 921 int s = splsoftnet(); 922 923 for (fp = LIST_FIRST(&ipq); fp != LIST_END(&ipq); fp = nfp) { 924 nfp = LIST_NEXT(fp, ipq_q); 925 if (--fp->ipq_ttl == 0) { 926 ipstat.ips_fragtimeout++; 927 ip_freef(fp); 928 } 929 } 930 if (ipforward_rt.ro_rt) { 931 RTFREE(ipforward_rt.ro_rt); 932 ipforward_rt.ro_rt = 0; 933 } 934 splx(s); 935 } 936 937 /* 938 * Drain off all datagram fragments. 939 */ 940 void 941 ip_drain() 942 { 943 944 while (!LIST_EMPTY(&ipq)) { 945 ipstat.ips_fragdropped++; 946 ip_freef(LIST_FIRST(&ipq)); 947 } 948 } 949 950 /* 951 * Flush a bunch of datagram fragments, till we are down to 75%. 952 */ 953 void 954 ip_flush() 955 { 956 int max = 50; 957 958 /* ipq already locked */ 959 while (!LIST_EMPTY(&ipq) && ip_frags > ip_maxqueue * 3 / 4 && --max) { 960 ipstat.ips_fragdropped++; 961 ip_freef(LIST_FIRST(&ipq)); 962 } 963 } 964 965 /* 966 * Do option processing on a datagram, 967 * possibly discarding it if bad options are encountered, 968 * or forwarding it if source-routed. 969 * Returns 1 if packet has been forwarded/freed, 970 * 0 if the packet should be processed further. 971 */ 972 int 973 ip_dooptions(m) 974 struct mbuf *m; 975 { 976 struct ip *ip = mtod(m, struct ip *); 977 u_char *cp; 978 struct ip_timestamp ipt; 979 struct in_ifaddr *ia; 980 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 981 struct in_addr sin, dst; 982 n_time ntime; 983 984 dst = ip->ip_dst; 985 cp = (u_char *)(ip + 1); 986 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 987 988 for (; cnt > 0; cnt -= optlen, cp += optlen) { 989 opt = cp[IPOPT_OPTVAL]; 990 if (opt == IPOPT_EOL) 991 break; 992 if (opt == IPOPT_NOP) 993 optlen = 1; 994 else { 995 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 996 code = &cp[IPOPT_OLEN] - (u_char *)ip; 997 goto bad; 998 } 999 optlen = cp[IPOPT_OLEN]; 1000 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1001 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1002 goto bad; 1003 } 1004 } 1005 1006 switch (opt) { 1007 1008 default: 1009 break; 1010 1011 /* 1012 * Source routing with record. 1013 * Find interface with current destination address. 1014 * If none on this machine then drop if strictly routed, 1015 * or do nothing if loosely routed. 1016 * Record interface address and bring up next address 1017 * component. If strictly routed make sure next 1018 * address is on directly accessible net. 1019 */ 1020 case IPOPT_LSRR: 1021 case IPOPT_SSRR: 1022 if (!ip_dosourceroute) { 1023 type = ICMP_UNREACH; 1024 code = ICMP_UNREACH_SRCFAIL; 1025 goto bad; 1026 } 1027 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1028 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1029 goto bad; 1030 } 1031 ipaddr.sin_addr = ip->ip_dst; 1032 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); 1033 if (ia == 0) { 1034 if (opt == IPOPT_SSRR) { 1035 type = ICMP_UNREACH; 1036 code = ICMP_UNREACH_SRCFAIL; 1037 goto bad; 1038 } 1039 /* 1040 * Loose routing, and not at next destination 1041 * yet; nothing to do except forward. 1042 */ 1043 break; 1044 } 1045 off--; /* 0 origin */ 1046 if ((off + sizeof(struct in_addr)) > optlen) { 1047 /* 1048 * End of source route. Should be for us. 1049 */ 1050 save_rte(cp, ip->ip_src); 1051 break; 1052 } 1053 1054 /* 1055 * locate outgoing interface 1056 */ 1057 bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr, 1058 sizeof(ipaddr.sin_addr)); 1059 if (opt == IPOPT_SSRR) { 1060 #define INA struct in_ifaddr * 1061 #define SA struct sockaddr * 1062 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1063 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1064 } else 1065 ia = ip_rtaddr(ipaddr.sin_addr); 1066 if (ia == 0) { 1067 type = ICMP_UNREACH; 1068 code = ICMP_UNREACH_SRCFAIL; 1069 goto bad; 1070 } 1071 ip->ip_dst = ipaddr.sin_addr; 1072 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1073 (caddr_t)(cp + off), sizeof(struct in_addr)); 1074 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1075 /* 1076 * Let ip_intr's mcast routing check handle mcast pkts 1077 */ 1078 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1079 break; 1080 1081 case IPOPT_RR: 1082 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1083 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1084 goto bad; 1085 } 1086 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1087 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1088 goto bad; 1089 } 1090 1091 /* 1092 * If no space remains, ignore. 1093 */ 1094 off--; /* 0 origin */ 1095 if ((off + sizeof(struct in_addr)) > optlen) 1096 break; 1097 bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr, 1098 sizeof(ipaddr.sin_addr)); 1099 /* 1100 * locate outgoing interface; if we're the destination, 1101 * use the incoming interface (should be same). 1102 */ 1103 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1104 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1105 type = ICMP_UNREACH; 1106 code = ICMP_UNREACH_HOST; 1107 goto bad; 1108 } 1109 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1110 (caddr_t)(cp + off), sizeof(struct in_addr)); 1111 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1112 break; 1113 1114 case IPOPT_TS: 1115 code = cp - (u_char *)ip; 1116 if (optlen < sizeof(struct ip_timestamp)) 1117 goto bad; 1118 bcopy(cp, &ipt, sizeof(struct ip_timestamp)); 1119 if (ipt.ipt_ptr < 5 || ipt.ipt_len < 5) 1120 goto bad; 1121 if (ipt.ipt_ptr - 1 + sizeof(n_time) > ipt.ipt_len) { 1122 if (++ipt.ipt_oflw == 0) 1123 goto bad; 1124 break; 1125 } 1126 bcopy(cp + ipt.ipt_ptr - 1, &sin, sizeof sin); 1127 switch (ipt.ipt_flg) { 1128 1129 case IPOPT_TS_TSONLY: 1130 break; 1131 1132 case IPOPT_TS_TSANDADDR: 1133 if (ipt.ipt_ptr - 1 + sizeof(n_time) + 1134 sizeof(struct in_addr) > ipt.ipt_len) 1135 goto bad; 1136 ipaddr.sin_addr = dst; 1137 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1138 m->m_pkthdr.rcvif); 1139 if (ia == 0) 1140 continue; 1141 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1142 (caddr_t)&sin, sizeof(struct in_addr)); 1143 ipt.ipt_ptr += sizeof(struct in_addr); 1144 break; 1145 1146 case IPOPT_TS_PRESPEC: 1147 if (ipt.ipt_ptr - 1 + sizeof(n_time) + 1148 sizeof(struct in_addr) > ipt.ipt_len) 1149 goto bad; 1150 bcopy((caddr_t)&sin, (caddr_t)&ipaddr.sin_addr, 1151 sizeof(struct in_addr)); 1152 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1153 continue; 1154 ipt.ipt_ptr += sizeof(struct in_addr); 1155 break; 1156 1157 default: 1158 /* XXX can't take &ipt->ipt_flg */ 1159 code = (u_char *)&ipt.ipt_ptr - 1160 (u_char *)ip + 1; 1161 goto bad; 1162 } 1163 ntime = iptime(); 1164 bcopy((caddr_t)&ntime, (caddr_t)cp + ipt.ipt_ptr - 1, 1165 sizeof(n_time)); 1166 ipt.ipt_ptr += sizeof(n_time); 1167 } 1168 } 1169 if (forward && ipforwarding) { 1170 ip_forward(m, 1); 1171 return (1); 1172 } 1173 return (0); 1174 bad: 1175 icmp_error(m, type, code, 0, 0); 1176 ipstat.ips_badoptions++; 1177 return (1); 1178 } 1179 1180 /* 1181 * Given address of next destination (final or next hop), 1182 * return internet address info of interface to be used to get there. 1183 */ 1184 struct in_ifaddr * 1185 ip_rtaddr(dst) 1186 struct in_addr dst; 1187 { 1188 struct sockaddr_in *sin; 1189 1190 sin = satosin(&ipforward_rt.ro_dst); 1191 1192 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 1193 if (ipforward_rt.ro_rt) { 1194 RTFREE(ipforward_rt.ro_rt); 1195 ipforward_rt.ro_rt = 0; 1196 } 1197 sin->sin_family = AF_INET; 1198 sin->sin_len = sizeof(*sin); 1199 sin->sin_addr = dst; 1200 1201 rtalloc(&ipforward_rt); 1202 } 1203 if (ipforward_rt.ro_rt == 0) 1204 return ((struct in_ifaddr *)0); 1205 return (ifatoia(ipforward_rt.ro_rt->rt_ifa)); 1206 } 1207 1208 /* 1209 * Save incoming source route for use in replies, 1210 * to be picked up later by ip_srcroute if the receiver is interested. 1211 */ 1212 void 1213 save_rte(option, dst) 1214 u_char *option; 1215 struct in_addr dst; 1216 { 1217 unsigned olen; 1218 1219 olen = option[IPOPT_OLEN]; 1220 #ifdef DIAGNOSTIC 1221 if (ipprintfs) 1222 printf("save_rte: olen %d\n", olen); 1223 #endif /* 0 */ 1224 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1225 return; 1226 bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen); 1227 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1228 ip_srcrt.dst = dst; 1229 } 1230 1231 /* 1232 * Check whether we do proxy ARP for this address and we point to ourselves. 1233 * Code shamelessly copied from arplookup(). 1234 */ 1235 int 1236 ip_weadvertise(addr) 1237 u_int32_t addr; 1238 { 1239 struct rtentry *rt; 1240 struct ifnet *ifp; 1241 struct ifaddr *ifa; 1242 struct sockaddr_inarp sin; 1243 1244 sin.sin_len = sizeof(sin); 1245 sin.sin_family = AF_INET; 1246 sin.sin_addr.s_addr = addr; 1247 sin.sin_other = SIN_PROXY; 1248 rt = rtalloc1(sintosa(&sin), 0, 0); /* XXX other tables? */ 1249 if (rt == 0) 1250 return 0; 1251 1252 if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || 1253 rt->rt_gateway->sa_family != AF_LINK) { 1254 RTFREE(rt); 1255 return 0; 1256 } 1257 1258 TAILQ_FOREACH(ifp, &ifnet, if_list) 1259 TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) { 1260 if (ifa->ifa_addr->sa_family != rt->rt_gateway->sa_family) 1261 continue; 1262 1263 if (!bcmp(LLADDR((struct sockaddr_dl *)ifa->ifa_addr), 1264 LLADDR((struct sockaddr_dl *)rt->rt_gateway), 1265 ETHER_ADDR_LEN)) { 1266 RTFREE(rt); 1267 return 1; 1268 } 1269 } 1270 1271 RTFREE(rt); 1272 return 0; 1273 } 1274 1275 /* 1276 * Retrieve incoming source route for use in replies, 1277 * in the same form used by setsockopt. 1278 * The first hop is placed before the options, will be removed later. 1279 */ 1280 struct mbuf * 1281 ip_srcroute() 1282 { 1283 struct in_addr *p, *q; 1284 struct mbuf *m; 1285 1286 if (ip_nhops == 0) 1287 return ((struct mbuf *)0); 1288 m = m_get(M_DONTWAIT, MT_SOOPTS); 1289 if (m == 0) 1290 return ((struct mbuf *)0); 1291 1292 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1293 1294 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1295 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1296 OPTSIZ; 1297 #ifdef DIAGNOSTIC 1298 if (ipprintfs) 1299 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1300 #endif 1301 1302 /* 1303 * First save first hop for return route 1304 */ 1305 p = &ip_srcrt.route[ip_nhops - 1]; 1306 *(mtod(m, struct in_addr *)) = *p--; 1307 #ifdef DIAGNOSTIC 1308 if (ipprintfs) 1309 printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1310 #endif 1311 1312 /* 1313 * Copy option fields and padding (nop) to mbuf. 1314 */ 1315 ip_srcrt.nop = IPOPT_NOP; 1316 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1317 bcopy((caddr_t)&ip_srcrt.nop, 1318 mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ); 1319 q = (struct in_addr *)(mtod(m, caddr_t) + 1320 sizeof(struct in_addr) + OPTSIZ); 1321 #undef OPTSIZ 1322 /* 1323 * Record return path as an IP source route, 1324 * reversing the path (pointers are now aligned). 1325 */ 1326 while (p >= ip_srcrt.route) { 1327 #ifdef DIAGNOSTIC 1328 if (ipprintfs) 1329 printf(" %x", ntohl(q->s_addr)); 1330 #endif 1331 *q++ = *p--; 1332 } 1333 /* 1334 * Last hop goes to final destination. 1335 */ 1336 *q = ip_srcrt.dst; 1337 #ifdef DIAGNOSTIC 1338 if (ipprintfs) 1339 printf(" %x\n", ntohl(q->s_addr)); 1340 #endif 1341 return (m); 1342 } 1343 1344 /* 1345 * Strip out IP options, at higher 1346 * level protocol in the kernel. 1347 * Second argument is buffer to which options 1348 * will be moved, and return value is their length. 1349 * XXX should be deleted; last arg currently ignored. 1350 */ 1351 void 1352 ip_stripoptions(m, mopt) 1353 struct mbuf *m; 1354 struct mbuf *mopt; 1355 { 1356 int i; 1357 struct ip *ip = mtod(m, struct ip *); 1358 caddr_t opts; 1359 int olen; 1360 1361 olen = (ip->ip_hl<<2) - sizeof (struct ip); 1362 opts = (caddr_t)(ip + 1); 1363 i = m->m_len - (sizeof (struct ip) + olen); 1364 bcopy(opts + olen, opts, (unsigned)i); 1365 m->m_len -= olen; 1366 if (m->m_flags & M_PKTHDR) 1367 m->m_pkthdr.len -= olen; 1368 ip->ip_hl = sizeof(struct ip) >> 2; 1369 } 1370 1371 int inetctlerrmap[PRC_NCMDS] = { 1372 0, 0, 0, 0, 1373 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1374 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1375 EMSGSIZE, EHOSTUNREACH, 0, 0, 1376 0, 0, 0, 0, 1377 ENOPROTOOPT 1378 }; 1379 1380 /* 1381 * Forward a packet. If some error occurs return the sender 1382 * an icmp packet. Note we can't always generate a meaningful 1383 * icmp message because icmp doesn't have a large enough repertoire 1384 * of codes and types. 1385 * 1386 * If not forwarding, just drop the packet. This could be confusing 1387 * if ipforwarding was zero but some routing protocol was advancing 1388 * us as a gateway to somewhere. However, we must let the routing 1389 * protocol deal with that. 1390 * 1391 * The srcrt parameter indicates whether the packet is being forwarded 1392 * via a source route. 1393 */ 1394 void 1395 ip_forward(m, srcrt) 1396 struct mbuf *m; 1397 int srcrt; 1398 { 1399 struct ip *ip = mtod(m, struct ip *); 1400 struct sockaddr_in *sin; 1401 struct rtentry *rt; 1402 int error, type = 0, code = 0, destmtu = 0, rtableid = 0; 1403 struct mbuf *mcopy; 1404 n_long dest; 1405 1406 dest = 0; 1407 #ifdef DIAGNOSTIC 1408 if (ipprintfs) 1409 printf("forward: src %x dst %x ttl %x\n", ip->ip_src.s_addr, 1410 ip->ip_dst.s_addr, ip->ip_ttl); 1411 #endif 1412 if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) { 1413 ipstat.ips_cantforward++; 1414 m_freem(m); 1415 return; 1416 } 1417 if (ip->ip_ttl <= IPTTLDEC) { 1418 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1419 return; 1420 } 1421 1422 #if NPF > 0 1423 rtableid = m->m_pkthdr.pf.rtableid; 1424 #endif 1425 1426 sin = satosin(&ipforward_rt.ro_dst); 1427 if ((rt = ipforward_rt.ro_rt) == 0 || 1428 ip->ip_dst.s_addr != sin->sin_addr.s_addr || 1429 rtableid != ipforward_rtableid) { 1430 if (ipforward_rt.ro_rt) { 1431 RTFREE(ipforward_rt.ro_rt); 1432 ipforward_rt.ro_rt = 0; 1433 } 1434 sin->sin_family = AF_INET; 1435 sin->sin_len = sizeof(*sin); 1436 sin->sin_addr = ip->ip_dst; 1437 1438 rtalloc_mpath(&ipforward_rt, &ip->ip_src.s_addr, rtableid); 1439 if (ipforward_rt.ro_rt == 0) { 1440 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1441 return; 1442 } 1443 ipforward_rtableid = rtableid; 1444 rt = ipforward_rt.ro_rt; 1445 } 1446 1447 /* 1448 * Save at most 68 bytes of the packet in case 1449 * we need to generate an ICMP message to the src. 1450 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1451 */ 1452 mcopy = m_copym(m, 0, min(ntohs(ip->ip_len), 68), M_DONTWAIT); 1453 if (mcopy) 1454 mcopy = m_pullup(mcopy, min(ntohs(ip->ip_len), 68)); 1455 1456 ip->ip_ttl -= IPTTLDEC; 1457 1458 /* 1459 * If forwarding packet using same interface that it came in on, 1460 * perhaps should send a redirect to sender to shortcut a hop. 1461 * Only send redirect if source is sending directly to us, 1462 * and if packet was not source routed (or has any options). 1463 * Also, don't send redirect if forwarding using a default route 1464 * or a route modified by a redirect. 1465 * Don't send redirect if we advertise destination's arp address 1466 * as ours (proxy arp). 1467 */ 1468 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1469 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1470 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1471 ipsendredirects && !srcrt && 1472 !ip_weadvertise(satosin(rt_key(rt))->sin_addr.s_addr)) { 1473 if (rt->rt_ifa && 1474 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1475 ifatoia(rt->rt_ifa)->ia_subnet) { 1476 if (rt->rt_flags & RTF_GATEWAY) 1477 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1478 else 1479 dest = ip->ip_dst.s_addr; 1480 /* Router requirements says to only send host redirects */ 1481 type = ICMP_REDIRECT; 1482 code = ICMP_REDIRECT_HOST; 1483 #ifdef DIAGNOSTIC 1484 if (ipprintfs) 1485 printf("redirect (%d) to %x\n", code, (u_int32_t)dest); 1486 #endif 1487 } 1488 } 1489 1490 error = ip_output(m, (struct mbuf *)NULL, &ipforward_rt, 1491 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1492 (void *)NULL, (void *)NULL); 1493 if (error) 1494 ipstat.ips_cantforward++; 1495 else { 1496 ipstat.ips_forward++; 1497 if (type) 1498 ipstat.ips_redirectsent++; 1499 else 1500 goto freecopy; 1501 } 1502 if (mcopy == NULL) 1503 goto freert; 1504 1505 switch (error) { 1506 1507 case 0: /* forwarded, but need redirect */ 1508 /* type, code set above */ 1509 break; 1510 1511 case ENETUNREACH: /* shouldn't happen, checked above */ 1512 case EHOSTUNREACH: 1513 case ENETDOWN: 1514 case EHOSTDOWN: 1515 default: 1516 type = ICMP_UNREACH; 1517 code = ICMP_UNREACH_HOST; 1518 break; 1519 1520 case EMSGSIZE: 1521 type = ICMP_UNREACH; 1522 code = ICMP_UNREACH_NEEDFRAG; 1523 1524 #ifdef IPSEC 1525 if (ipforward_rt.ro_rt) { 1526 struct rtentry *rt = ipforward_rt.ro_rt; 1527 1528 if (rt->rt_rmx.rmx_mtu) 1529 destmtu = rt->rt_rmx.rmx_mtu; 1530 else 1531 destmtu = ipforward_rt.ro_rt->rt_ifp->if_mtu; 1532 } 1533 #endif /*IPSEC*/ 1534 ipstat.ips_cantfrag++; 1535 break; 1536 1537 case ENOBUFS: 1538 #if 1 1539 /* 1540 * a router should not generate ICMP_SOURCEQUENCH as 1541 * required in RFC1812 Requirements for IP Version 4 Routers. 1542 * source quench could be a big problem under DoS attacks, 1543 * or the underlying interface is rate-limited. 1544 */ 1545 goto freecopy; 1546 #else 1547 type = ICMP_SOURCEQUENCH; 1548 code = 0; 1549 break; 1550 #endif 1551 } 1552 1553 icmp_error(mcopy, type, code, dest, destmtu); 1554 goto freert; 1555 1556 freecopy: 1557 if (mcopy) 1558 m_free(mcopy); 1559 freert: 1560 #ifndef SMALL_KERNEL 1561 if (ipmultipath && ipforward_rt.ro_rt && 1562 (ipforward_rt.ro_rt->rt_flags & RTF_MPATH)) { 1563 RTFREE(ipforward_rt.ro_rt); 1564 ipforward_rt.ro_rt = 0; 1565 } 1566 #endif 1567 return; 1568 } 1569 1570 int 1571 ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 1572 int *name; 1573 u_int namelen; 1574 void *oldp; 1575 size_t *oldlenp; 1576 void *newp; 1577 size_t newlen; 1578 { 1579 int error; 1580 #ifdef MROUTING 1581 extern int ip_mrtproto; 1582 extern struct mrtstat mrtstat; 1583 #endif 1584 1585 /* Almost all sysctl names at this level are terminal. */ 1586 if (namelen != 1 && name[0] != IPCTL_IFQUEUE) 1587 return (ENOTDIR); 1588 1589 switch (name[0]) { 1590 #ifdef notyet 1591 case IPCTL_DEFMTU: 1592 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu)); 1593 #endif 1594 case IPCTL_SOURCEROUTE: 1595 /* 1596 * Don't allow this to change in a secure environment. 1597 */ 1598 if (newp && securelevel > 0) 1599 return (EPERM); 1600 return (sysctl_int(oldp, oldlenp, newp, newlen, 1601 &ip_dosourceroute)); 1602 case IPCTL_MTUDISC: 1603 error = sysctl_int(oldp, oldlenp, newp, newlen, 1604 &ip_mtudisc); 1605 if (ip_mtudisc != 0 && ip_mtudisc_timeout_q == NULL) { 1606 ip_mtudisc_timeout_q = 1607 rt_timer_queue_create(ip_mtudisc_timeout); 1608 } else if (ip_mtudisc == 0 && ip_mtudisc_timeout_q != NULL) { 1609 rt_timer_queue_destroy(ip_mtudisc_timeout_q, TRUE); 1610 Free(ip_mtudisc_timeout_q); 1611 ip_mtudisc_timeout_q = NULL; 1612 } 1613 return error; 1614 case IPCTL_MTUDISCTIMEOUT: 1615 error = sysctl_int(oldp, oldlenp, newp, newlen, 1616 &ip_mtudisc_timeout); 1617 if (ip_mtudisc_timeout_q != NULL) 1618 rt_timer_queue_change(ip_mtudisc_timeout_q, 1619 ip_mtudisc_timeout); 1620 return (error); 1621 case IPCTL_IPSEC_ENC_ALGORITHM: 1622 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1623 ipsec_def_enc, sizeof(ipsec_def_enc))); 1624 case IPCTL_IPSEC_AUTH_ALGORITHM: 1625 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1626 ipsec_def_auth, 1627 sizeof(ipsec_def_auth))); 1628 case IPCTL_IPSEC_IPCOMP_ALGORITHM: 1629 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1630 ipsec_def_comp, 1631 sizeof(ipsec_def_comp))); 1632 case IPCTL_IFQUEUE: 1633 return (sysctl_ifq(name + 1, namelen - 1, 1634 oldp, oldlenp, newp, newlen, &ipintrq)); 1635 case IPCTL_STATS: 1636 if (newp != NULL) 1637 return (EPERM); 1638 return (sysctl_struct(oldp, oldlenp, newp, newlen, 1639 &ipstat, sizeof(ipstat))); 1640 case IPCTL_MRTSTATS: 1641 #ifdef MROUTING 1642 if (newp != NULL) 1643 return (EPERM); 1644 return (sysctl_struct(oldp, oldlenp, newp, newlen, 1645 &mrtstat, sizeof(mrtstat))); 1646 #else 1647 return (EOPNOTSUPP); 1648 #endif 1649 case IPCTL_MRTPROTO: 1650 #ifdef MROUTING 1651 return (sysctl_rdint(oldp, oldlenp, newp, ip_mrtproto)); 1652 #else 1653 return (EOPNOTSUPP); 1654 #endif 1655 default: 1656 if (name[0] < IPCTL_MAXID) 1657 return (sysctl_int_arr(ipctl_vars, name, namelen, 1658 oldp, oldlenp, newp, newlen)); 1659 return (EOPNOTSUPP); 1660 } 1661 /* NOTREACHED */ 1662 } 1663 1664 void 1665 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip, 1666 struct mbuf *m) 1667 { 1668 #ifdef SO_TIMESTAMP 1669 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1670 struct timeval tv; 1671 1672 microtime(&tv); 1673 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1674 SCM_TIMESTAMP, SOL_SOCKET); 1675 if (*mp) 1676 mp = &(*mp)->m_next; 1677 } 1678 #endif 1679 if (inp->inp_flags & INP_RECVDSTADDR) { 1680 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1681 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1682 if (*mp) 1683 mp = &(*mp)->m_next; 1684 } 1685 #ifdef notyet 1686 /* this code is broken and will probably never be fixed. */ 1687 /* options were tossed already */ 1688 if (inp->inp_flags & INP_RECVOPTS) { 1689 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1690 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1691 if (*mp) 1692 mp = &(*mp)->m_next; 1693 } 1694 /* ip_srcroute doesn't do what we want here, need to fix */ 1695 if (inp->inp_flags & INP_RECVRETOPTS) { 1696 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1697 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1698 if (*mp) 1699 mp = &(*mp)->m_next; 1700 } 1701 #endif 1702 if (inp->inp_flags & INP_RECVIF) { 1703 struct sockaddr_dl sdl; 1704 struct ifnet *ifp; 1705 1706 if ((ifp = m->m_pkthdr.rcvif) == NULL || 1707 ifp->if_sadl == NULL) { 1708 bzero(&sdl, sizeof(sdl)); 1709 sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]); 1710 sdl.sdl_family = AF_LINK; 1711 sdl.sdl_index = ifp != NULL ? ifp->if_index : 0; 1712 sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0; 1713 *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len, 1714 IP_RECVIF, IPPROTO_IP); 1715 } else { 1716 *mp = sbcreatecontrol((caddr_t) ifp->if_sadl, 1717 ifp->if_sadl->sdl_len, IP_RECVIF, IPPROTO_IP); 1718 } 1719 if (*mp) 1720 mp = &(*mp)->m_next; 1721 } 1722 if (inp->inp_flags & INP_RECVTTL) { 1723 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl, 1724 sizeof(u_char), IP_RECVTTL, IPPROTO_IP); 1725 if (*mp) 1726 mp = &(*mp)->m_next; 1727 } 1728 } 1729 1730