1 /* $OpenBSD: ip_input.c,v 1.114 2003/07/29 03:21:57 itojun 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 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/mbuf.h> 40 #include <sys/domain.h> 41 #include <sys/protosw.h> 42 #include <sys/socket.h> 43 #include <sys/syslog.h> 44 #include <sys/sysctl.h> 45 46 #include <net/if.h> 47 #include <net/if_dl.h> 48 #include <net/route.h> 49 50 #include <netinet/in.h> 51 #include <netinet/in_systm.h> 52 #include <netinet/if_ether.h> 53 #include <netinet/ip.h> 54 #include <netinet/in_pcb.h> 55 #include <netinet/in_var.h> 56 #include <netinet/ip_var.h> 57 #include <netinet/ip_icmp.h> 58 59 #if NPF > 0 60 #include <net/pfvar.h> 61 #endif 62 63 #ifdef IPSEC 64 #include <netinet/ip_ipsp.h> 65 #endif /* IPSEC */ 66 67 #ifndef IPFORWARDING 68 #ifdef GATEWAY 69 #define IPFORWARDING 1 /* forward IP packets not for us */ 70 #else /* GATEWAY */ 71 #define IPFORWARDING 0 /* don't forward IP packets not for us */ 72 #endif /* GATEWAY */ 73 #endif /* IPFORWARDING */ 74 #ifndef IPSENDREDIRECTS 75 #define IPSENDREDIRECTS 1 76 #endif 77 78 #ifndef IPMTUDISC 79 #define IPMTUDISC 1 80 #endif 81 #ifndef IPMTUDISCTIMEOUT 82 #define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */ 83 #endif 84 85 struct ipqhead ipq; 86 87 int encdebug = 0; 88 int ipsec_keep_invalid = IPSEC_DEFAULT_EMBRYONIC_SA_TIMEOUT; 89 int ipsec_require_pfs = IPSEC_DEFAULT_PFS; 90 int ipsec_soft_allocations = IPSEC_DEFAULT_SOFT_ALLOCATIONS; 91 int ipsec_exp_allocations = IPSEC_DEFAULT_EXP_ALLOCATIONS; 92 int ipsec_soft_bytes = IPSEC_DEFAULT_SOFT_BYTES; 93 int ipsec_exp_bytes = IPSEC_DEFAULT_EXP_BYTES; 94 int ipsec_soft_timeout = IPSEC_DEFAULT_SOFT_TIMEOUT; 95 int ipsec_exp_timeout = IPSEC_DEFAULT_EXP_TIMEOUT; 96 int ipsec_soft_first_use = IPSEC_DEFAULT_SOFT_FIRST_USE; 97 int ipsec_exp_first_use = IPSEC_DEFAULT_EXP_FIRST_USE; 98 int ipsec_expire_acquire = IPSEC_DEFAULT_EXPIRE_ACQUIRE; 99 char ipsec_def_enc[20]; 100 char ipsec_def_auth[20]; 101 char ipsec_def_comp[20]; 102 103 /* 104 * Note: DIRECTED_BROADCAST is handled this way so that previous 105 * configuration using this option will Just Work. 106 */ 107 #ifndef IPDIRECTEDBCAST 108 #ifdef DIRECTED_BROADCAST 109 #define IPDIRECTEDBCAST 1 110 #else 111 #define IPDIRECTEDBCAST 0 112 #endif /* DIRECTED_BROADCAST */ 113 #endif /* IPDIRECTEDBCAST */ 114 int ipforwarding = IPFORWARDING; 115 int ipsendredirects = IPSENDREDIRECTS; 116 int ip_dosourceroute = 0; /* no src-routing unless sysctl'd to enable */ 117 int ip_defttl = IPDEFTTL; 118 int ip_mtudisc = IPMTUDISC; 119 u_int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 120 int ip_directedbcast = IPDIRECTEDBCAST; 121 #ifdef DIAGNOSTIC 122 int ipprintfs = 0; 123 #endif 124 125 struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 126 127 int ipsec_auth_default_level = IPSEC_AUTH_LEVEL_DEFAULT; 128 int ipsec_esp_trans_default_level = IPSEC_ESP_TRANS_LEVEL_DEFAULT; 129 int ipsec_esp_network_default_level = IPSEC_ESP_NETWORK_LEVEL_DEFAULT; 130 int ipsec_ipcomp_default_level = IPSEC_IPCOMP_LEVEL_DEFAULT; 131 132 /* Keep track of memory used for reassembly */ 133 int ip_maxqueue = 300; 134 int ip_frags = 0; 135 136 /* from in_pcb.c */ 137 extern int ipport_firstauto; 138 extern int ipport_lastauto; 139 extern int ipport_hifirstauto; 140 extern int ipport_hilastauto; 141 extern struct baddynamicports baddynamicports; 142 143 extern struct domain inetdomain; 144 extern struct protosw inetsw[]; 145 u_char ip_protox[IPPROTO_MAX]; 146 int ipqmaxlen = IFQ_MAXLEN; 147 struct in_ifaddrhead in_ifaddr; 148 struct ifqueue ipintrq; 149 150 int ipq_locked; 151 static __inline int ipq_lock_try(void); 152 static __inline void ipq_unlock(void); 153 154 struct pool ipqent_pool; 155 156 struct ipstat ipstat; 157 158 static __inline int 159 ipq_lock_try() 160 { 161 int s; 162 163 s = splimp(); 164 if (ipq_locked) { 165 splx(s); 166 return (0); 167 } 168 ipq_locked = 1; 169 splx(s); 170 return (1); 171 } 172 173 #define ipq_lock() ipq_lock_try() 174 175 static __inline void 176 ipq_unlock() 177 { 178 int s; 179 180 s = splimp(); 181 ipq_locked = 0; 182 splx(s); 183 } 184 185 char * 186 inet_ntoa(ina) 187 struct in_addr ina; 188 { 189 static char buf[4*sizeof "123"]; 190 unsigned char *ucp = (unsigned char *)&ina; 191 192 snprintf(buf, sizeof buf, "%d.%d.%d.%d", 193 ucp[0] & 0xff, ucp[1] & 0xff, 194 ucp[2] & 0xff, ucp[3] & 0xff); 195 return (buf); 196 } 197 198 /* 199 * We need to save the IP options in case a protocol wants to respond 200 * to an incoming packet over the same route if the packet got here 201 * using IP source routing. This allows connection establishment and 202 * maintenance when the remote end is on a network that is not known 203 * to us. 204 */ 205 int ip_nhops = 0; 206 static struct ip_srcrt { 207 struct in_addr dst; /* final destination */ 208 char nop; /* one NOP to align */ 209 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 210 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 211 } ip_srcrt; 212 213 static void save_rte(u_char *, struct in_addr); 214 static int ip_weadvertise(u_int32_t); 215 216 /* 217 * IP initialization: fill in IP protocol switch table. 218 * All protocols not implemented in kernel go to raw IP protocol handler. 219 */ 220 void 221 ip_init() 222 { 223 register struct protosw *pr; 224 register int i; 225 const u_int16_t defbaddynamicports_tcp[] = DEFBADDYNAMICPORTS_TCP; 226 const u_int16_t defbaddynamicports_udp[] = DEFBADDYNAMICPORTS_UDP; 227 228 pool_init(&ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl", 229 NULL); 230 231 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 232 if (pr == 0) 233 panic("ip_init"); 234 for (i = 0; i < IPPROTO_MAX; i++) 235 ip_protox[i] = pr - inetsw; 236 for (pr = inetdomain.dom_protosw; 237 pr < inetdomain.dom_protoswNPROTOSW; pr++) 238 if (pr->pr_domain->dom_family == PF_INET && 239 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 240 ip_protox[pr->pr_protocol] = pr - inetsw; 241 LIST_INIT(&ipq); 242 ipintrq.ifq_maxlen = ipqmaxlen; 243 TAILQ_INIT(&in_ifaddr); 244 if (ip_mtudisc != 0) 245 ip_mtudisc_timeout_q = 246 rt_timer_queue_create(ip_mtudisc_timeout); 247 248 /* Fill in list of ports not to allocate dynamically. */ 249 bzero((void *)&baddynamicports, sizeof(baddynamicports)); 250 for (i = 0; defbaddynamicports_tcp[i] != 0; i++) 251 DP_SET(baddynamicports.tcp, defbaddynamicports_tcp[i]); 252 for (i = 0; defbaddynamicports_udp[i] != 0; i++) 253 DP_SET(baddynamicports.udp, defbaddynamicports_tcp[i]); 254 255 strncpy(ipsec_def_enc, IPSEC_DEFAULT_DEF_ENC, sizeof(ipsec_def_enc)); 256 strncpy(ipsec_def_auth, IPSEC_DEFAULT_DEF_AUTH, sizeof(ipsec_def_auth)); 257 strncpy(ipsec_def_comp, IPSEC_DEFAULT_DEF_COMP, sizeof(ipsec_def_comp)); 258 } 259 260 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 261 struct route ipforward_rt; 262 263 void 264 ipintr() 265 { 266 struct mbuf *m; 267 int s; 268 269 while (1) { 270 /* 271 * Get next datagram off input queue and get IP header 272 * in first mbuf. 273 */ 274 s = splimp(); 275 IF_DEQUEUE(&ipintrq, m); 276 splx(s); 277 if (m == 0) 278 return; 279 #ifdef DIAGNOSTIC 280 if ((m->m_flags & M_PKTHDR) == 0) 281 panic("ipintr no HDR"); 282 #endif 283 ipv4_input(m); 284 } 285 } 286 287 /* 288 * Ip input routine. Checksum and byte swap header. If fragmented 289 * try to reassemble. Process options. Pass to next level. 290 */ 291 void 292 ipv4_input(m) 293 struct mbuf *m; 294 { 295 register struct ip *ip; 296 register struct ipq *fp; 297 struct in_ifaddr *ia; 298 struct ipqent *ipqe; 299 int hlen, mff, len; 300 in_addr_t pfrdr = 0; 301 #ifdef IPSEC 302 int error, s; 303 struct tdb *tdb; 304 struct tdb_ident *tdbi; 305 struct m_tag *mtag; 306 #endif /* IPSEC */ 307 308 /* 309 * If no IP addresses have been set yet but the interfaces 310 * are receiving, can't do anything with incoming packets yet. 311 */ 312 if (in_ifaddr.tqh_first == 0) 313 goto bad; 314 ipstat.ips_total++; 315 if (m->m_len < sizeof (struct ip) && 316 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 317 ipstat.ips_toosmall++; 318 return; 319 } 320 ip = mtod(m, struct ip *); 321 if (ip->ip_v != IPVERSION) { 322 ipstat.ips_badvers++; 323 goto bad; 324 } 325 hlen = ip->ip_hl << 2; 326 if (hlen < sizeof(struct ip)) { /* minimum header length */ 327 ipstat.ips_badhlen++; 328 goto bad; 329 } 330 if (hlen > m->m_len) { 331 if ((m = m_pullup(m, hlen)) == NULL) { 332 ipstat.ips_badhlen++; 333 return; 334 } 335 ip = mtod(m, struct ip *); 336 } 337 338 /* 127/8 must not appear on wire - RFC1122 */ 339 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 340 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 341 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 342 ipstat.ips_badaddr++; 343 goto bad; 344 } 345 } 346 347 if ((m->m_pkthdr.csum & M_IPV4_CSUM_IN_OK) == 0) { 348 if (m->m_pkthdr.csum & M_IPV4_CSUM_IN_BAD) { 349 ipstat.ips_inhwcsum++; 350 ipstat.ips_badsum++; 351 goto bad; 352 } 353 354 if (in_cksum(m, hlen) != 0) { 355 ipstat.ips_badsum++; 356 goto bad; 357 } 358 } else { 359 m->m_pkthdr.csum &= ~M_IPV4_CSUM_IN_OK; 360 ipstat.ips_inhwcsum++; 361 } 362 363 /* Retrieve the packet lenght. */ 364 len = ntohs(ip->ip_len); 365 366 /* 367 * Convert fields to host representation. 368 */ 369 if (len < hlen) { 370 ipstat.ips_badlen++; 371 goto bad; 372 } 373 374 /* 375 * Check that the amount of data in the buffers 376 * is at least as much as the IP header would have us expect. 377 * Trim mbufs if longer than we expect. 378 * Drop packet if shorter than we expect. 379 */ 380 if (m->m_pkthdr.len < len) { 381 ipstat.ips_tooshort++; 382 goto bad; 383 } 384 if (m->m_pkthdr.len > len) { 385 if (m->m_len == m->m_pkthdr.len) { 386 m->m_len = len; 387 m->m_pkthdr.len = len; 388 } else 389 m_adj(m, len - m->m_pkthdr.len); 390 } 391 392 #if NPF > 0 393 /* 394 * Packet filter 395 */ 396 pfrdr = ip->ip_dst.s_addr; 397 if (pf_test(PF_IN, m->m_pkthdr.rcvif, &m) != PF_PASS) 398 goto bad; 399 if (m == NULL) 400 return; 401 402 ip = mtod(m, struct ip *); 403 hlen = ip->ip_hl << 2; 404 pfrdr = (pfrdr != ip->ip_dst.s_addr); 405 #endif 406 407 /* 408 * Process options and, if not destined for us, 409 * ship it on. ip_dooptions returns 1 when an 410 * error was detected (causing an icmp message 411 * to be sent and the original packet to be freed). 412 */ 413 ip_nhops = 0; /* for source routed packets */ 414 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 415 return; 416 } 417 418 /* 419 * Check our list of addresses, to see if the packet is for us. 420 */ 421 if ((ia = in_iawithaddr(ip->ip_dst, m)) != NULL && 422 (ia->ia_ifp->if_flags & IFF_UP)) 423 goto ours; 424 425 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 426 struct in_multi *inm; 427 #ifdef MROUTING 428 extern struct socket *ip_mrouter; 429 430 if (m->m_flags & M_EXT) { 431 if ((m = m_pullup(m, hlen)) == NULL) { 432 ipstat.ips_toosmall++; 433 return; 434 } 435 ip = mtod(m, struct ip *); 436 } 437 438 if (ip_mrouter) { 439 /* 440 * If we are acting as a multicast router, all 441 * incoming multicast packets are passed to the 442 * kernel-level multicast forwarding function. 443 * The packet is returned (relatively) intact; if 444 * ip_mforward() returns a non-zero value, the packet 445 * must be discarded, else it may be accepted below. 446 * 447 * (The IP ident field is put in the same byte order 448 * as expected when ip_mforward() is called from 449 * ip_output().) 450 */ 451 if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) { 452 ipstat.ips_cantforward++; 453 m_freem(m); 454 return; 455 } 456 457 /* 458 * The process-level routing demon needs to receive 459 * all multicast IGMP packets, whether or not this 460 * host belongs to their destination groups. 461 */ 462 if (ip->ip_p == IPPROTO_IGMP) 463 goto ours; 464 ipstat.ips_forward++; 465 } 466 #endif 467 /* 468 * See if we belong to the destination multicast group on the 469 * arrival interface. 470 */ 471 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 472 if (inm == NULL) { 473 ipstat.ips_cantforward++; 474 m_freem(m); 475 return; 476 } 477 goto ours; 478 } 479 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 480 ip->ip_dst.s_addr == INADDR_ANY) 481 goto ours; 482 483 /* 484 * Not for us; forward if possible and desirable. 485 */ 486 if (ipforwarding == 0) { 487 ipstat.ips_cantforward++; 488 m_freem(m); 489 } else { 490 #ifdef IPSEC 491 /* 492 * IPsec policy check for forwarded packets. Look at 493 * inner-most IPsec SA used. 494 */ 495 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 496 s = splnet(); 497 if (mtag != NULL) { 498 tdbi = (struct tdb_ident *)(mtag + 1); 499 tdb = gettdb(tdbi->spi, &tdbi->dst, tdbi->proto); 500 } else 501 tdb = NULL; 502 ipsp_spd_lookup(m, AF_INET, hlen, &error, 503 IPSP_DIRECTION_IN, tdb, NULL); 504 splx(s); 505 506 /* Error or otherwise drop-packet indication */ 507 if (error) { 508 ipstat.ips_cantforward++; 509 m_freem(m); 510 return; 511 } 512 513 /* 514 * Fall through, forward packet. Outbound IPsec policy 515 * checking will occur in ip_output(). 516 */ 517 #endif /* IPSEC */ 518 519 ip_forward(m, pfrdr); 520 } 521 return; 522 523 ours: 524 /* 525 * If offset or IP_MF are set, must reassemble. 526 * Otherwise, nothing need be done. 527 * (We could look in the reassembly queue to see 528 * if the packet was previously fragmented, 529 * but it's not worth the time; just let them time out.) 530 */ 531 if (ip->ip_off &~ htons(IP_DF | IP_RF)) { 532 if (m->m_flags & M_EXT) { /* XXX */ 533 if ((m = m_pullup(m, hlen)) == NULL) { 534 ipstat.ips_toosmall++; 535 return; 536 } 537 ip = mtod(m, struct ip *); 538 } 539 540 /* 541 * Look for queue of fragments 542 * of this datagram. 543 */ 544 ipq_lock(); 545 for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next) 546 if (ip->ip_id == fp->ipq_id && 547 ip->ip_src.s_addr == fp->ipq_src.s_addr && 548 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 549 ip->ip_p == fp->ipq_p) 550 goto found; 551 fp = 0; 552 found: 553 554 /* 555 * Adjust ip_len to not reflect header, 556 * set ipqe_mff if more fragments are expected, 557 * convert offset of this to bytes. 558 */ 559 ip->ip_len = htons(ntohs(ip->ip_len) - hlen); 560 mff = (ip->ip_off & htons(IP_MF)) != 0; 561 if (mff) { 562 /* 563 * Make sure that fragments have a data length 564 * that's a non-zero multiple of 8 bytes. 565 */ 566 if (ntohs(ip->ip_len) == 0 || 567 (ntohs(ip->ip_len) & 0x7) != 0) { 568 ipstat.ips_badfrags++; 569 ipq_unlock(); 570 goto bad; 571 } 572 } 573 ip->ip_off = htons(ntohs(ip->ip_off) << 3); 574 575 /* 576 * If datagram marked as having more fragments 577 * or if this is not the first fragment, 578 * attempt reassembly; if it succeeds, proceed. 579 */ 580 if (mff || ip->ip_off) { 581 ipstat.ips_fragments++; 582 if (ip_frags + 1 > ip_maxqueue) { 583 ip_flush(); 584 ipstat.ips_rcvmemdrop++; 585 ipq_unlock(); 586 goto bad; 587 } 588 589 ipqe = pool_get(&ipqent_pool, PR_NOWAIT); 590 if (ipqe == NULL) { 591 ipstat.ips_rcvmemdrop++; 592 ipq_unlock(); 593 goto bad; 594 } 595 ip_frags++; 596 ipqe->ipqe_mff = mff; 597 ipqe->ipqe_m = m; 598 ipqe->ipqe_ip = ip; 599 m = ip_reass(ipqe, fp); 600 if (m == 0) { 601 ipq_unlock(); 602 return; 603 } 604 ipstat.ips_reassembled++; 605 ip = mtod(m, struct ip *); 606 hlen = ip->ip_hl << 2; 607 ip->ip_len = htons(ntohs(ip->ip_len) + hlen); 608 } else 609 if (fp) 610 ip_freef(fp); 611 ipq_unlock(); 612 } 613 614 #ifdef IPSEC 615 /* 616 * If it's a protected packet for us, skip the policy check. 617 * That's because we really only care about the properties of 618 * the protected packet, and not the intermediate versions. 619 * While this is not the most paranoid setting, it allows 620 * some flexibility in handling nested tunnels (in setting up 621 * the policies). 622 */ 623 if ((ip->ip_p == IPPROTO_ESP) || (ip->ip_p == IPPROTO_AH) || 624 (ip->ip_p == IPPROTO_IPCOMP)) 625 goto skipipsec; 626 627 /* 628 * If the protected packet was tunneled, then we need to 629 * verify the protected packet's information, not the 630 * external headers. Thus, skip the policy lookup for the 631 * external packet, and keep the IPsec information linked on 632 * the packet header (the encapsulation routines know how 633 * to deal with that). 634 */ 635 if ((ip->ip_p == IPPROTO_IPIP) || (ip->ip_p == IPPROTO_IPV6)) 636 goto skipipsec; 637 638 /* 639 * If the protected packet is TCP or UDP, we'll do the 640 * policy check in the respective input routine, so we can 641 * check for bypass sockets. 642 */ 643 if ((ip->ip_p == IPPROTO_TCP) || (ip->ip_p == IPPROTO_UDP)) 644 goto skipipsec; 645 646 /* 647 * IPsec policy check for local-delivery packets. Look at the 648 * inner-most SA that protected the packet. This is in fact 649 * a bit too restrictive (it could end up causing packets to 650 * be dropped that semantically follow the policy, e.g., in 651 * certain SA-bundle configurations); but the alternative is 652 * very complicated (and requires keeping track of what 653 * kinds of tunneling headers have been seen in-between the 654 * IPsec headers), and I don't think we lose much functionality 655 * that's needed in the real world (who uses bundles anyway ?). 656 */ 657 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 658 s = splnet(); 659 if (mtag) { 660 tdbi = (struct tdb_ident *)(mtag + 1); 661 tdb = gettdb(tdbi->spi, &tdbi->dst, tdbi->proto); 662 } else 663 tdb = NULL; 664 ipsp_spd_lookup(m, AF_INET, hlen, &error, IPSP_DIRECTION_IN, 665 tdb, NULL); 666 splx(s); 667 668 /* Error or otherwise drop-packet indication. */ 669 if (error) { 670 ipstat.ips_cantforward++; 671 m_freem(m); 672 return; 673 } 674 675 skipipsec: 676 /* Otherwise, just fall through and deliver the packet */ 677 #endif /* IPSEC */ 678 679 /* 680 * Switch out to protocol's input routine. 681 */ 682 ipstat.ips_delivered++; 683 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, NULL, 0); 684 return; 685 bad: 686 m_freem(m); 687 } 688 689 struct in_ifaddr * 690 in_iawithaddr(ina, m) 691 struct in_addr ina; 692 register struct mbuf *m; 693 { 694 register struct in_ifaddr *ia; 695 696 TAILQ_FOREACH(ia, &in_ifaddr, ia_list) { 697 if ((ina.s_addr == ia->ia_addr.sin_addr.s_addr) || 698 ((ia->ia_ifp->if_flags & (IFF_LOOPBACK|IFF_LINK1)) == 699 (IFF_LOOPBACK|IFF_LINK1) && 700 ia->ia_subnet == (ina.s_addr & ia->ia_subnetmask))) 701 return ia; 702 if (((ip_directedbcast == 0) || (m && ip_directedbcast && 703 ia->ia_ifp == m->m_pkthdr.rcvif)) && 704 (ia->ia_ifp->if_flags & IFF_BROADCAST)) { 705 if (ina.s_addr == ia->ia_broadaddr.sin_addr.s_addr || 706 ina.s_addr == ia->ia_netbroadcast.s_addr || 707 /* 708 * Look for all-0's host part (old broadcast addr), 709 * either for subnet or net. 710 */ 711 ina.s_addr == ia->ia_subnet || 712 ina.s_addr == ia->ia_net) { 713 /* Make sure M_BCAST is set */ 714 if (m) 715 m->m_flags |= M_BCAST; 716 return ia; 717 } 718 } 719 } 720 721 return NULL; 722 } 723 724 /* 725 * Take incoming datagram fragment and try to 726 * reassemble it into whole datagram. If a chain for 727 * reassembly of this datagram already exists, then it 728 * is given as fp; otherwise have to make a chain. 729 */ 730 struct mbuf * 731 ip_reass(ipqe, fp) 732 struct ipqent *ipqe; 733 struct ipq *fp; 734 { 735 struct mbuf *m = ipqe->ipqe_m; 736 struct ipqent *nq, *p, *q; 737 struct ip *ip; 738 struct mbuf *t; 739 int hlen = ipqe->ipqe_ip->ip_hl << 2; 740 int i, next; 741 u_int8_t ecn, ecn0; 742 743 /* 744 * Presence of header sizes in mbufs 745 * would confuse code below. 746 */ 747 m->m_data += hlen; 748 m->m_len -= hlen; 749 750 /* 751 * If first fragment to arrive, create a reassembly queue. 752 */ 753 if (fp == 0) { 754 MALLOC(fp, struct ipq *, sizeof (struct ipq), 755 M_FTABLE, M_NOWAIT); 756 if (fp == NULL) 757 goto dropfrag; 758 LIST_INSERT_HEAD(&ipq, fp, ipq_q); 759 fp->ipq_ttl = IPFRAGTTL; 760 fp->ipq_p = ipqe->ipqe_ip->ip_p; 761 fp->ipq_id = ipqe->ipqe_ip->ip_id; 762 LIST_INIT(&fp->ipq_fragq); 763 fp->ipq_src = ipqe->ipqe_ip->ip_src; 764 fp->ipq_dst = ipqe->ipqe_ip->ip_dst; 765 p = NULL; 766 goto insert; 767 } 768 769 /* 770 * Handle ECN by comparing this segment with the first one; 771 * if CE is set, do not lose CE. 772 * drop if CE and not-ECT are mixed for the same packet. 773 */ 774 ecn = ipqe->ipqe_ip->ip_tos & IPTOS_ECN_MASK; 775 ecn0 = fp->ipq_fragq.lh_first->ipqe_ip->ip_tos & IPTOS_ECN_MASK; 776 if (ecn == IPTOS_ECN_CE) { 777 if (ecn0 == IPTOS_ECN_NOTECT) 778 goto dropfrag; 779 if (ecn0 != IPTOS_ECN_CE) 780 fp->ipq_fragq.lh_first->ipqe_ip->ip_tos |= IPTOS_ECN_CE; 781 } 782 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) 783 goto dropfrag; 784 785 /* 786 * Find a segment which begins after this one does. 787 */ 788 for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL; 789 p = q, q = q->ipqe_q.le_next) 790 if (ntohs(q->ipqe_ip->ip_off) > ntohs(ipqe->ipqe_ip->ip_off)) 791 break; 792 793 /* 794 * If there is a preceding segment, it may provide some of 795 * our data already. If so, drop the data from the incoming 796 * segment. If it provides all of our data, drop us. 797 */ 798 if (p != NULL) { 799 i = ntohs(p->ipqe_ip->ip_off) + ntohs(p->ipqe_ip->ip_len) - 800 ntohs(ipqe->ipqe_ip->ip_off); 801 if (i > 0) { 802 if (i >= ntohs(ipqe->ipqe_ip->ip_len)) 803 goto dropfrag; 804 m_adj(ipqe->ipqe_m, i); 805 ipqe->ipqe_ip->ip_off = 806 htons(ntohs(ipqe->ipqe_ip->ip_off) + i); 807 ipqe->ipqe_ip->ip_len = 808 htons(ntohs(ipqe->ipqe_ip->ip_len) - i); 809 } 810 } 811 812 /* 813 * While we overlap succeeding segments trim them or, 814 * if they are completely covered, dequeue them. 815 */ 816 for (; q != NULL && 817 ntohs(ipqe->ipqe_ip->ip_off) + ntohs(ipqe->ipqe_ip->ip_len) > 818 ntohs(q->ipqe_ip->ip_off); q = nq) { 819 i = (ntohs(ipqe->ipqe_ip->ip_off) + 820 ntohs(ipqe->ipqe_ip->ip_len)) - ntohs(q->ipqe_ip->ip_off); 821 if (i < ntohs(q->ipqe_ip->ip_len)) { 822 q->ipqe_ip->ip_len = 823 htons(ntohs(q->ipqe_ip->ip_len) - i); 824 q->ipqe_ip->ip_off = 825 htons(ntohs(q->ipqe_ip->ip_off) + i); 826 m_adj(q->ipqe_m, i); 827 break; 828 } 829 nq = q->ipqe_q.le_next; 830 m_freem(q->ipqe_m); 831 LIST_REMOVE(q, ipqe_q); 832 pool_put(&ipqent_pool, q); 833 ip_frags--; 834 } 835 836 insert: 837 /* 838 * Stick new segment in its place; 839 * check for complete reassembly. 840 */ 841 if (p == NULL) { 842 LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); 843 } else { 844 LIST_INSERT_AFTER(p, ipqe, ipqe_q); 845 } 846 next = 0; 847 for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL; 848 p = q, q = q->ipqe_q.le_next) { 849 if (ntohs(q->ipqe_ip->ip_off) != next) 850 return (0); 851 next += ntohs(q->ipqe_ip->ip_len); 852 } 853 if (p->ipqe_mff) 854 return (0); 855 856 /* 857 * Reassembly is complete. Check for a bogus message size and 858 * concatenate fragments. 859 */ 860 q = fp->ipq_fragq.lh_first; 861 ip = q->ipqe_ip; 862 if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) { 863 ipstat.ips_toolong++; 864 ip_freef(fp); 865 return (0); 866 } 867 m = q->ipqe_m; 868 t = m->m_next; 869 m->m_next = 0; 870 m_cat(m, t); 871 nq = q->ipqe_q.le_next; 872 pool_put(&ipqent_pool, q); 873 ip_frags--; 874 for (q = nq; q != NULL; q = nq) { 875 t = q->ipqe_m; 876 nq = q->ipqe_q.le_next; 877 pool_put(&ipqent_pool, q); 878 ip_frags--; 879 m_cat(m, t); 880 } 881 882 /* 883 * Create header for new ip packet by 884 * modifying header of first packet; 885 * dequeue and discard fragment reassembly header. 886 * Make header visible. 887 */ 888 ip->ip_len = htons(next); 889 ip->ip_src = fp->ipq_src; 890 ip->ip_dst = fp->ipq_dst; 891 LIST_REMOVE(fp, ipq_q); 892 FREE(fp, M_FTABLE); 893 m->m_len += (ip->ip_hl << 2); 894 m->m_data -= (ip->ip_hl << 2); 895 /* some debugging cruft by sklower, below, will go away soon */ 896 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 897 int plen = 0; 898 for (t = m; t; t = t->m_next) 899 plen += t->m_len; 900 m->m_pkthdr.len = plen; 901 } 902 return (m); 903 904 dropfrag: 905 ipstat.ips_fragdropped++; 906 m_freem(m); 907 pool_put(&ipqent_pool, ipqe); 908 ip_frags--; 909 return (0); 910 } 911 912 /* 913 * Free a fragment reassembly header and all 914 * associated datagrams. 915 */ 916 void 917 ip_freef(fp) 918 struct ipq *fp; 919 { 920 register struct ipqent *q, *p; 921 922 for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) { 923 p = q->ipqe_q.le_next; 924 m_freem(q->ipqe_m); 925 LIST_REMOVE(q, ipqe_q); 926 pool_put(&ipqent_pool, q); 927 ip_frags--; 928 } 929 LIST_REMOVE(fp, ipq_q); 930 FREE(fp, M_FTABLE); 931 } 932 933 /* 934 * IP timer processing; 935 * if a timer expires on a reassembly 936 * queue, discard it. 937 */ 938 void 939 ip_slowtimo() 940 { 941 register struct ipq *fp, *nfp; 942 int s = splsoftnet(); 943 944 ipq_lock(); 945 for (fp = ipq.lh_first; fp != NULL; fp = nfp) { 946 nfp = fp->ipq_q.le_next; 947 if (--fp->ipq_ttl == 0) { 948 ipstat.ips_fragtimeout++; 949 ip_freef(fp); 950 } 951 } 952 ipq_unlock(); 953 splx(s); 954 } 955 956 /* 957 * Drain off all datagram fragments. 958 */ 959 void 960 ip_drain() 961 { 962 963 if (ipq_lock_try() == 0) 964 return; 965 while (ipq.lh_first != NULL) { 966 ipstat.ips_fragdropped++; 967 ip_freef(ipq.lh_first); 968 } 969 ipq_unlock(); 970 } 971 972 /* 973 * Flush a bunch of datagram fragments, till we are down to 75%. 974 */ 975 void 976 ip_flush() 977 { 978 int max = 50; 979 980 /* ipq already locked */ 981 while (ipq.lh_first != NULL && ip_frags > ip_maxqueue * 3 / 4 && --max) { 982 ipstat.ips_fragdropped++; 983 ip_freef(ipq.lh_first); 984 } 985 } 986 987 /* 988 * Do option processing on a datagram, 989 * possibly discarding it if bad options are encountered, 990 * or forwarding it if source-routed. 991 * Returns 1 if packet has been forwarded/freed, 992 * 0 if the packet should be processed further. 993 */ 994 int 995 ip_dooptions(m) 996 struct mbuf *m; 997 { 998 register struct ip *ip = mtod(m, struct ip *); 999 register u_char *cp; 1000 struct ip_timestamp ipt; 1001 register struct in_ifaddr *ia; 1002 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1003 struct in_addr sin, dst; 1004 n_time ntime; 1005 1006 dst = ip->ip_dst; 1007 cp = (u_char *)(ip + 1); 1008 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 1009 1010 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1011 opt = cp[IPOPT_OPTVAL]; 1012 if (opt == IPOPT_EOL) 1013 break; 1014 if (opt == IPOPT_NOP) 1015 optlen = 1; 1016 else { 1017 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 1018 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1019 goto bad; 1020 } 1021 optlen = cp[IPOPT_OLEN]; 1022 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 1023 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1024 goto bad; 1025 } 1026 } 1027 1028 switch (opt) { 1029 1030 default: 1031 break; 1032 1033 /* 1034 * Source routing with record. 1035 * Find interface with current destination address. 1036 * If none on this machine then drop if strictly routed, 1037 * or do nothing if loosely routed. 1038 * Record interface address and bring up next address 1039 * component. If strictly routed make sure next 1040 * address is on directly accessible net. 1041 */ 1042 case IPOPT_LSRR: 1043 case IPOPT_SSRR: 1044 if (!ip_dosourceroute) { 1045 char buf[4*sizeof "123"]; 1046 1047 strlcpy(buf, inet_ntoa(ip->ip_dst), 1048 sizeof buf); 1049 log(LOG_WARNING, 1050 "attempted source route from %s to %s\n", 1051 inet_ntoa(ip->ip_src), buf); 1052 type = ICMP_UNREACH; 1053 code = ICMP_UNREACH_SRCFAIL; 1054 goto bad; 1055 } 1056 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1057 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1058 goto bad; 1059 } 1060 ipaddr.sin_addr = ip->ip_dst; 1061 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); 1062 if (ia == 0) { 1063 if (opt == IPOPT_SSRR) { 1064 type = ICMP_UNREACH; 1065 code = ICMP_UNREACH_SRCFAIL; 1066 goto bad; 1067 } 1068 /* 1069 * Loose routing, and not at next destination 1070 * yet; nothing to do except forward. 1071 */ 1072 break; 1073 } 1074 off--; /* 0 origin */ 1075 if ((off + sizeof(struct in_addr)) > optlen) { 1076 /* 1077 * End of source route. Should be for us. 1078 */ 1079 save_rte(cp, ip->ip_src); 1080 break; 1081 } 1082 1083 /* 1084 * locate outgoing interface 1085 */ 1086 bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr, 1087 sizeof(ipaddr.sin_addr)); 1088 if (opt == IPOPT_SSRR) { 1089 #define INA struct in_ifaddr * 1090 #define SA struct sockaddr * 1091 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1092 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1093 } else 1094 ia = ip_rtaddr(ipaddr.sin_addr); 1095 if (ia == 0) { 1096 type = ICMP_UNREACH; 1097 code = ICMP_UNREACH_SRCFAIL; 1098 goto bad; 1099 } 1100 ip->ip_dst = ipaddr.sin_addr; 1101 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1102 (caddr_t)(cp + off), sizeof(struct in_addr)); 1103 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1104 /* 1105 * Let ip_intr's mcast routing check handle mcast pkts 1106 */ 1107 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1108 break; 1109 1110 case IPOPT_RR: 1111 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1112 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1113 goto bad; 1114 } 1115 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1116 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1117 goto bad; 1118 } 1119 1120 /* 1121 * If no space remains, ignore. 1122 */ 1123 off--; /* 0 origin */ 1124 if ((off + sizeof(struct in_addr)) > optlen) 1125 break; 1126 bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr, 1127 sizeof(ipaddr.sin_addr)); 1128 /* 1129 * locate outgoing interface; if we're the destination, 1130 * use the incoming interface (should be same). 1131 */ 1132 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1133 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1134 type = ICMP_UNREACH; 1135 code = ICMP_UNREACH_HOST; 1136 goto bad; 1137 } 1138 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1139 (caddr_t)(cp + off), sizeof(struct in_addr)); 1140 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1141 break; 1142 1143 case IPOPT_TS: 1144 code = cp - (u_char *)ip; 1145 bcopy(cp, &ipt, sizeof(struct ip_timestamp)); 1146 if (ipt.ipt_ptr < 5 || ipt.ipt_len < 5) 1147 goto bad; 1148 if (ipt.ipt_ptr - 1 + sizeof(n_time) > ipt.ipt_len) { 1149 if (++ipt.ipt_oflw == 0) 1150 goto bad; 1151 break; 1152 } 1153 bcopy(cp + ipt.ipt_ptr - 1, &sin, sizeof sin); 1154 switch (ipt.ipt_flg) { 1155 1156 case IPOPT_TS_TSONLY: 1157 break; 1158 1159 case IPOPT_TS_TSANDADDR: 1160 if (ipt.ipt_ptr - 1 + sizeof(n_time) + 1161 sizeof(struct in_addr) > ipt.ipt_len) 1162 goto bad; 1163 ipaddr.sin_addr = dst; 1164 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1165 m->m_pkthdr.rcvif); 1166 if (ia == 0) 1167 continue; 1168 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1169 (caddr_t)&sin, sizeof(struct in_addr)); 1170 ipt.ipt_ptr += sizeof(struct in_addr); 1171 break; 1172 1173 case IPOPT_TS_PRESPEC: 1174 if (ipt.ipt_ptr - 1 + sizeof(n_time) + 1175 sizeof(struct in_addr) > ipt.ipt_len) 1176 goto bad; 1177 bcopy((caddr_t)&sin, (caddr_t)&ipaddr.sin_addr, 1178 sizeof(struct in_addr)); 1179 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1180 continue; 1181 ipt.ipt_ptr += sizeof(struct in_addr); 1182 break; 1183 1184 default: 1185 /* XXX can't take &ipt->ipt_flg */ 1186 code = (u_char *)&ipt.ipt_ptr - 1187 (u_char *)ip + 1; 1188 goto bad; 1189 } 1190 ntime = iptime(); 1191 bcopy((caddr_t)&ntime, (caddr_t)cp + ipt.ipt_ptr - 1, 1192 sizeof(n_time)); 1193 ipt.ipt_ptr += sizeof(n_time); 1194 } 1195 } 1196 if (forward && ipforwarding) { 1197 ip_forward(m, 1); 1198 return (1); 1199 } 1200 return (0); 1201 bad: 1202 icmp_error(m, type, code, 0, 0); 1203 ipstat.ips_badoptions++; 1204 return (1); 1205 } 1206 1207 /* 1208 * Given address of next destination (final or next hop), 1209 * return internet address info of interface to be used to get there. 1210 */ 1211 struct in_ifaddr * 1212 ip_rtaddr(dst) 1213 struct in_addr dst; 1214 { 1215 register struct sockaddr_in *sin; 1216 1217 sin = satosin(&ipforward_rt.ro_dst); 1218 1219 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 1220 if (ipforward_rt.ro_rt) { 1221 RTFREE(ipforward_rt.ro_rt); 1222 ipforward_rt.ro_rt = 0; 1223 } 1224 sin->sin_family = AF_INET; 1225 sin->sin_len = sizeof(*sin); 1226 sin->sin_addr = dst; 1227 1228 rtalloc(&ipforward_rt); 1229 } 1230 if (ipforward_rt.ro_rt == 0) 1231 return ((struct in_ifaddr *)0); 1232 return (ifatoia(ipforward_rt.ro_rt->rt_ifa)); 1233 } 1234 1235 /* 1236 * Save incoming source route for use in replies, 1237 * to be picked up later by ip_srcroute if the receiver is interested. 1238 */ 1239 void 1240 save_rte(option, dst) 1241 u_char *option; 1242 struct in_addr dst; 1243 { 1244 unsigned olen; 1245 1246 olen = option[IPOPT_OLEN]; 1247 #ifdef DIAGNOSTIC 1248 if (ipprintfs) 1249 printf("save_rte: olen %d\n", olen); 1250 #endif /* 0 */ 1251 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1252 return; 1253 bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen); 1254 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1255 ip_srcrt.dst = dst; 1256 } 1257 1258 /* 1259 * Check whether we do proxy ARP for this address and we point to ourselves. 1260 * Code shamelessly copied from arplookup(). 1261 */ 1262 static int 1263 ip_weadvertise(addr) 1264 u_int32_t addr; 1265 { 1266 register struct rtentry *rt; 1267 register struct ifnet *ifp; 1268 register struct ifaddr *ifa; 1269 struct sockaddr_inarp sin; 1270 1271 sin.sin_len = sizeof(sin); 1272 sin.sin_family = AF_INET; 1273 sin.sin_addr.s_addr = addr; 1274 sin.sin_other = SIN_PROXY; 1275 rt = rtalloc1(sintosa(&sin), 0); 1276 if (rt == 0) 1277 return 0; 1278 1279 if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || 1280 rt->rt_gateway->sa_family != AF_LINK) { 1281 RTFREE(rt); 1282 return 0; 1283 } 1284 1285 for (ifp = ifnet.tqh_first; ifp != 0; ifp = ifp->if_list.tqe_next) 1286 for (ifa = ifp->if_addrlist.tqh_first; ifa != 0; 1287 ifa = ifa->ifa_list.tqe_next) { 1288 if (ifa->ifa_addr->sa_family != rt->rt_gateway->sa_family) 1289 continue; 1290 1291 if (!bcmp(LLADDR((struct sockaddr_dl *)ifa->ifa_addr), 1292 LLADDR((struct sockaddr_dl *)rt->rt_gateway), 1293 ETHER_ADDR_LEN)) { 1294 RTFREE(rt); 1295 return 1; 1296 } 1297 } 1298 1299 RTFREE(rt); 1300 return 0; 1301 } 1302 1303 /* 1304 * Retrieve incoming source route for use in replies, 1305 * in the same form used by setsockopt. 1306 * The first hop is placed before the options, will be removed later. 1307 */ 1308 struct mbuf * 1309 ip_srcroute() 1310 { 1311 register struct in_addr *p, *q; 1312 register struct mbuf *m; 1313 1314 if (ip_nhops == 0) 1315 return ((struct mbuf *)0); 1316 m = m_get(M_DONTWAIT, MT_SOOPTS); 1317 if (m == 0) 1318 return ((struct mbuf *)0); 1319 1320 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1321 1322 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1323 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1324 OPTSIZ; 1325 #ifdef DIAGNOSTIC 1326 if (ipprintfs) 1327 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1328 #endif 1329 1330 /* 1331 * First save first hop for return route 1332 */ 1333 p = &ip_srcrt.route[ip_nhops - 1]; 1334 *(mtod(m, struct in_addr *)) = *p--; 1335 #ifdef DIAGNOSTIC 1336 if (ipprintfs) 1337 printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1338 #endif 1339 1340 /* 1341 * Copy option fields and padding (nop) to mbuf. 1342 */ 1343 ip_srcrt.nop = IPOPT_NOP; 1344 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1345 bcopy((caddr_t)&ip_srcrt.nop, 1346 mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ); 1347 q = (struct in_addr *)(mtod(m, caddr_t) + 1348 sizeof(struct in_addr) + OPTSIZ); 1349 #undef OPTSIZ 1350 /* 1351 * Record return path as an IP source route, 1352 * reversing the path (pointers are now aligned). 1353 */ 1354 while (p >= ip_srcrt.route) { 1355 #ifdef DIAGNOSTIC 1356 if (ipprintfs) 1357 printf(" %x", ntohl(q->s_addr)); 1358 #endif 1359 *q++ = *p--; 1360 } 1361 /* 1362 * Last hop goes to final destination. 1363 */ 1364 *q = ip_srcrt.dst; 1365 #ifdef DIAGNOSTIC 1366 if (ipprintfs) 1367 printf(" %x\n", ntohl(q->s_addr)); 1368 #endif 1369 return (m); 1370 } 1371 1372 /* 1373 * Strip out IP options, at higher 1374 * level protocol in the kernel. 1375 * Second argument is buffer to which options 1376 * will be moved, and return value is their length. 1377 * XXX should be deleted; last arg currently ignored. 1378 */ 1379 void 1380 ip_stripoptions(m, mopt) 1381 register struct mbuf *m; 1382 struct mbuf *mopt; 1383 { 1384 register int i; 1385 struct ip *ip = mtod(m, struct ip *); 1386 register caddr_t opts; 1387 int olen; 1388 1389 olen = (ip->ip_hl<<2) - sizeof (struct ip); 1390 opts = (caddr_t)(ip + 1); 1391 i = m->m_len - (sizeof (struct ip) + olen); 1392 bcopy(opts + olen, opts, (unsigned)i); 1393 m->m_len -= olen; 1394 if (m->m_flags & M_PKTHDR) 1395 m->m_pkthdr.len -= olen; 1396 ip->ip_hl = sizeof(struct ip) >> 2; 1397 } 1398 1399 int inetctlerrmap[PRC_NCMDS] = { 1400 0, 0, 0, 0, 1401 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1402 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1403 EMSGSIZE, EHOSTUNREACH, 0, 0, 1404 0, 0, 0, 0, 1405 ENOPROTOOPT 1406 }; 1407 1408 /* 1409 * Forward a packet. If some error occurs return the sender 1410 * an icmp packet. Note we can't always generate a meaningful 1411 * icmp message because icmp doesn't have a large enough repertoire 1412 * of codes and types. 1413 * 1414 * If not forwarding, just drop the packet. This could be confusing 1415 * if ipforwarding was zero but some routing protocol was advancing 1416 * us as a gateway to somewhere. However, we must let the routing 1417 * protocol deal with that. 1418 * 1419 * The srcrt parameter indicates whether the packet is being forwarded 1420 * via a source route. 1421 */ 1422 void 1423 ip_forward(m, srcrt) 1424 struct mbuf *m; 1425 int srcrt; 1426 { 1427 register struct ip *ip = mtod(m, struct ip *); 1428 register struct sockaddr_in *sin; 1429 register struct rtentry *rt; 1430 int error, type = 0, code = 0; 1431 struct mbuf *mcopy; 1432 n_long dest; 1433 struct ifnet *destifp; 1434 #ifdef IPSEC 1435 struct ifnet dummyifp; 1436 #endif 1437 1438 dest = 0; 1439 #ifdef DIAGNOSTIC 1440 if (ipprintfs) 1441 printf("forward: src %x dst %x ttl %x\n", ip->ip_src.s_addr, 1442 ip->ip_dst.s_addr, ip->ip_ttl); 1443 #endif 1444 if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) { 1445 ipstat.ips_cantforward++; 1446 m_freem(m); 1447 return; 1448 } 1449 if (ip->ip_ttl <= IPTTLDEC) { 1450 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1451 return; 1452 } 1453 ip->ip_ttl -= IPTTLDEC; 1454 1455 sin = satosin(&ipforward_rt.ro_dst); 1456 if ((rt = ipforward_rt.ro_rt) == 0 || 1457 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1458 if (ipforward_rt.ro_rt) { 1459 RTFREE(ipforward_rt.ro_rt); 1460 ipforward_rt.ro_rt = 0; 1461 } 1462 sin->sin_family = AF_INET; 1463 sin->sin_len = sizeof(*sin); 1464 sin->sin_addr = ip->ip_dst; 1465 1466 rtalloc(&ipforward_rt); 1467 if (ipforward_rt.ro_rt == 0) { 1468 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1469 return; 1470 } 1471 rt = ipforward_rt.ro_rt; 1472 } 1473 1474 /* 1475 * Save at most 68 bytes of the packet in case 1476 * we need to generate an ICMP message to the src. 1477 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1478 */ 1479 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT); 1480 if (mcopy) 1481 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1482 1483 /* 1484 * If forwarding packet using same interface that it came in on, 1485 * perhaps should send a redirect to sender to shortcut a hop. 1486 * Only send redirect if source is sending directly to us, 1487 * and if packet was not source routed (or has any options). 1488 * Also, don't send redirect if forwarding using a default route 1489 * or a route modified by a redirect. 1490 * Don't send redirect if we advertise destination's arp address 1491 * as ours (proxy arp). 1492 */ 1493 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1494 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1495 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1496 ipsendredirects && !srcrt && 1497 !ip_weadvertise(satosin(rt_key(rt))->sin_addr.s_addr)) { 1498 if (rt->rt_ifa && 1499 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1500 ifatoia(rt->rt_ifa)->ia_subnet) { 1501 if (rt->rt_flags & RTF_GATEWAY) 1502 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1503 else 1504 dest = ip->ip_dst.s_addr; 1505 /* Router requirements says to only send host redirects */ 1506 type = ICMP_REDIRECT; 1507 code = ICMP_REDIRECT_HOST; 1508 #ifdef DIAGNOSTIC 1509 if (ipprintfs) 1510 printf("redirect (%d) to %x\n", code, (u_int32_t)dest); 1511 #endif 1512 } 1513 } 1514 1515 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1516 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1517 0, (void *)NULL, (void *)NULL); 1518 if (error) 1519 ipstat.ips_cantforward++; 1520 else { 1521 ipstat.ips_forward++; 1522 if (type) 1523 ipstat.ips_redirectsent++; 1524 else { 1525 if (mcopy) 1526 m_freem(mcopy); 1527 return; 1528 } 1529 } 1530 if (mcopy == NULL) 1531 return; 1532 destifp = NULL; 1533 1534 switch (error) { 1535 1536 case 0: /* forwarded, but need redirect */ 1537 /* type, code set above */ 1538 break; 1539 1540 case ENETUNREACH: /* shouldn't happen, checked above */ 1541 case EHOSTUNREACH: 1542 case ENETDOWN: 1543 case EHOSTDOWN: 1544 default: 1545 type = ICMP_UNREACH; 1546 code = ICMP_UNREACH_HOST; 1547 break; 1548 1549 case EMSGSIZE: 1550 type = ICMP_UNREACH; 1551 code = ICMP_UNREACH_NEEDFRAG; 1552 1553 #ifdef IPSEC 1554 if (ipforward_rt.ro_rt) { 1555 struct rtentry *rt = ipforward_rt.ro_rt; 1556 destifp = ipforward_rt.ro_rt->rt_ifp; 1557 /* 1558 * XXX BUG ALERT 1559 * The "dummyifp" code relies upon the fact 1560 * that icmp_error() touches only ifp->if_mtu. 1561 */ 1562 if (rt->rt_rmx.rmx_mtu) { 1563 dummyifp.if_mtu = rt->rt_rmx.rmx_mtu; 1564 destifp = &dummyifp; 1565 } 1566 } 1567 #endif /*IPSEC*/ 1568 ipstat.ips_cantfrag++; 1569 break; 1570 1571 case ENOBUFS: 1572 #if 1 1573 /* 1574 * a router should not generate ICMP_SOURCEQUENCH as 1575 * required in RFC1812 Requirements for IP Version 4 Routers. 1576 * source quench could be a big problem under DoS attacks, 1577 * or the underlying interface is rate-limited. 1578 */ 1579 if (mcopy) 1580 m_freem(mcopy); 1581 return; 1582 #else 1583 type = ICMP_SOURCEQUENCH; 1584 code = 0; 1585 break; 1586 #endif 1587 } 1588 1589 icmp_error(mcopy, type, code, dest, destifp); 1590 } 1591 1592 int 1593 ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 1594 int *name; 1595 u_int namelen; 1596 void *oldp; 1597 size_t *oldlenp; 1598 void *newp; 1599 size_t newlen; 1600 { 1601 int error; 1602 1603 /* All sysctl names at this level are terminal. */ 1604 if (namelen != 1) 1605 return (ENOTDIR); 1606 1607 switch (name[0]) { 1608 case IPCTL_FORWARDING: 1609 return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding)); 1610 case IPCTL_SENDREDIRECTS: 1611 return (sysctl_int(oldp, oldlenp, newp, newlen, 1612 &ipsendredirects)); 1613 case IPCTL_DEFTTL: 1614 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl)); 1615 #ifdef notyet 1616 case IPCTL_DEFMTU: 1617 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu)); 1618 #endif 1619 case IPCTL_SOURCEROUTE: 1620 /* 1621 * Don't allow this to change in a secure environment. 1622 */ 1623 if (newp && securelevel > 0) 1624 return (EPERM); 1625 return (sysctl_int(oldp, oldlenp, newp, newlen, 1626 &ip_dosourceroute)); 1627 case IPCTL_DIRECTEDBCAST: 1628 return (sysctl_int(oldp, oldlenp, newp, newlen, 1629 &ip_directedbcast)); 1630 case IPCTL_MTUDISC: 1631 error = sysctl_int(oldp, oldlenp, newp, newlen, 1632 &ip_mtudisc); 1633 if (ip_mtudisc != 0 && ip_mtudisc_timeout_q == NULL) { 1634 ip_mtudisc_timeout_q = 1635 rt_timer_queue_create(ip_mtudisc_timeout); 1636 } else if (ip_mtudisc == 0 && ip_mtudisc_timeout_q != NULL) { 1637 rt_timer_queue_destroy(ip_mtudisc_timeout_q, TRUE); 1638 Free(ip_mtudisc_timeout_q); 1639 ip_mtudisc_timeout_q = NULL; 1640 } 1641 return error; 1642 case IPCTL_MTUDISCTIMEOUT: 1643 error = sysctl_int(oldp, oldlenp, newp, newlen, 1644 &ip_mtudisc_timeout); 1645 if (ip_mtudisc_timeout_q != NULL) 1646 rt_timer_queue_change(ip_mtudisc_timeout_q, 1647 ip_mtudisc_timeout); 1648 return (error); 1649 case IPCTL_IPPORT_FIRSTAUTO: 1650 return (sysctl_int(oldp, oldlenp, newp, newlen, 1651 &ipport_firstauto)); 1652 case IPCTL_IPPORT_LASTAUTO: 1653 return (sysctl_int(oldp, oldlenp, newp, newlen, 1654 &ipport_lastauto)); 1655 case IPCTL_IPPORT_HIFIRSTAUTO: 1656 return (sysctl_int(oldp, oldlenp, newp, newlen, 1657 &ipport_hifirstauto)); 1658 case IPCTL_IPPORT_HILASTAUTO: 1659 return (sysctl_int(oldp, oldlenp, newp, newlen, 1660 &ipport_hilastauto)); 1661 case IPCTL_IPPORT_MAXQUEUE: 1662 return (sysctl_int(oldp, oldlenp, newp, newlen, 1663 &ip_maxqueue)); 1664 case IPCTL_ENCDEBUG: 1665 return (sysctl_int(oldp, oldlenp, newp, newlen, &encdebug)); 1666 case IPCTL_IPSEC_EMBRYONIC_SA_TIMEOUT: 1667 return (sysctl_int(oldp, oldlenp, newp, newlen, 1668 &ipsec_keep_invalid)); 1669 case IPCTL_IPSEC_REQUIRE_PFS: 1670 return (sysctl_int(oldp, oldlenp, newp, newlen, 1671 &ipsec_require_pfs)); 1672 case IPCTL_IPSEC_SOFT_ALLOCATIONS: 1673 return (sysctl_int(oldp, oldlenp, newp, newlen, 1674 &ipsec_soft_allocations)); 1675 case IPCTL_IPSEC_ALLOCATIONS: 1676 return (sysctl_int(oldp, oldlenp, newp, newlen, 1677 &ipsec_exp_allocations)); 1678 case IPCTL_IPSEC_SOFT_BYTES: 1679 return (sysctl_int(oldp, oldlenp, newp, newlen, 1680 &ipsec_soft_bytes)); 1681 case IPCTL_IPSEC_BYTES: 1682 return (sysctl_int(oldp, oldlenp, newp, newlen, 1683 &ipsec_exp_bytes)); 1684 case IPCTL_IPSEC_TIMEOUT: 1685 return (sysctl_int(oldp, oldlenp, newp, newlen, 1686 &ipsec_exp_timeout)); 1687 case IPCTL_IPSEC_SOFT_TIMEOUT: 1688 return (sysctl_int(oldp, oldlenp, newp, newlen, 1689 &ipsec_soft_timeout)); 1690 case IPCTL_IPSEC_SOFT_FIRSTUSE: 1691 return (sysctl_int(oldp, oldlenp, newp, newlen, 1692 &ipsec_soft_first_use)); 1693 case IPCTL_IPSEC_FIRSTUSE: 1694 return (sysctl_int(oldp, oldlenp, newp, newlen, 1695 &ipsec_exp_first_use)); 1696 case IPCTL_IPSEC_ENC_ALGORITHM: 1697 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1698 ipsec_def_enc, sizeof(ipsec_def_enc))); 1699 case IPCTL_IPSEC_AUTH_ALGORITHM: 1700 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1701 ipsec_def_auth, 1702 sizeof(ipsec_def_auth))); 1703 case IPCTL_IPSEC_EXPIRE_ACQUIRE: 1704 return (sysctl_int(oldp, oldlenp, newp, newlen, 1705 &ipsec_expire_acquire)); 1706 case IPCTL_IPSEC_IPCOMP_ALGORITHM: 1707 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1708 ipsec_def_comp, 1709 sizeof(ipsec_def_comp))); 1710 default: 1711 return (EOPNOTSUPP); 1712 } 1713 /* NOTREACHED */ 1714 } 1715