1 /* $OpenBSD: ip_input.c,v 1.96 2001/12/10 12:05:40 ho 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 37 */ 38 39 #include "pf.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/mbuf.h> 44 #include <sys/domain.h> 45 #include <sys/protosw.h> 46 #include <sys/socket.h> 47 #include <sys/syslog.h> 48 #include <sys/sysctl.h> 49 50 #include <net/if.h> 51 #include <net/if_dl.h> 52 #include <net/route.h> 53 54 #include <netinet/in.h> 55 #include <netinet/in_systm.h> 56 #include <netinet/if_ether.h> 57 #include <netinet/ip.h> 58 #include <netinet/in_pcb.h> 59 #include <netinet/in_var.h> 60 #include <netinet/ip_var.h> 61 #include <netinet/ip_icmp.h> 62 63 #if NPF > 0 64 #include <net/pfvar.h> 65 #endif 66 67 #ifdef IPSEC 68 #include <netinet/ip_ipsp.h> 69 #endif /* IPSEC */ 70 71 #ifndef IPFORWARDING 72 #ifdef GATEWAY 73 #define IPFORWARDING 1 /* forward IP packets not for us */ 74 #else /* GATEWAY */ 75 #define IPFORWARDING 0 /* don't forward IP packets not for us */ 76 #endif /* GATEWAY */ 77 #endif /* IPFORWARDING */ 78 #ifndef IPSENDREDIRECTS 79 #define IPSENDREDIRECTS 1 80 #endif 81 82 #ifndef IPMTUDISC 83 #define IPMTUDISC 1 84 #endif 85 #ifndef IPMTUDISCTIMEOUT 86 #define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */ 87 #endif 88 89 int encdebug = 0; 90 int ipsec_keep_invalid = IPSEC_DEFAULT_EMBRYONIC_SA_TIMEOUT; 91 int ipsec_require_pfs = IPSEC_DEFAULT_PFS; 92 int ipsec_soft_allocations = IPSEC_DEFAULT_SOFT_ALLOCATIONS; 93 int ipsec_exp_allocations = IPSEC_DEFAULT_EXP_ALLOCATIONS; 94 int ipsec_soft_bytes = IPSEC_DEFAULT_SOFT_BYTES; 95 int ipsec_exp_bytes = IPSEC_DEFAULT_EXP_BYTES; 96 int ipsec_soft_timeout = IPSEC_DEFAULT_SOFT_TIMEOUT; 97 int ipsec_exp_timeout = IPSEC_DEFAULT_EXP_TIMEOUT; 98 int ipsec_soft_first_use = IPSEC_DEFAULT_SOFT_FIRST_USE; 99 int ipsec_exp_first_use = IPSEC_DEFAULT_EXP_FIRST_USE; 100 int ipsec_expire_acquire = IPSEC_DEFAULT_EXPIRE_ACQUIRE; 101 char ipsec_def_enc[20]; 102 char ipsec_def_auth[20]; 103 char ipsec_def_comp[20]; 104 105 /* 106 * Note: DIRECTED_BROADCAST is handled this way so that previous 107 * configuration using this option will Just Work. 108 */ 109 #ifndef IPDIRECTEDBCAST 110 #ifdef DIRECTED_BROADCAST 111 #define IPDIRECTEDBCAST 1 112 #else 113 #define IPDIRECTEDBCAST 0 114 #endif /* DIRECTED_BROADCAST */ 115 #endif /* IPDIRECTEDBCAST */ 116 int ipforwarding = IPFORWARDING; 117 int ipsendredirects = IPSENDREDIRECTS; 118 int ip_dosourceroute = 0; /* no src-routing unless sysctl'd to enable */ 119 int ip_defttl = IPDEFTTL; 120 int ip_mtudisc = IPMTUDISC; 121 u_int ip_mtudisc_timeout = IPMTUDISCTIMEOUT; 122 int ip_directedbcast = IPDIRECTEDBCAST; 123 #ifdef DIAGNOSTIC 124 int ipprintfs = 0; 125 #endif 126 127 struct rttimer_queue *ip_mtudisc_timeout_q = NULL; 128 129 int ipsec_auth_default_level = IPSEC_AUTH_LEVEL_DEFAULT; 130 int ipsec_esp_trans_default_level = IPSEC_ESP_TRANS_LEVEL_DEFAULT; 131 int ipsec_esp_network_default_level = IPSEC_ESP_NETWORK_LEVEL_DEFAULT; 132 int ipsec_ipcomp_default_level = IPSEC_IPCOMP_LEVEL_DEFAULT; 133 134 /* Keep track of memory used for reassembly */ 135 int ip_maxqueue = 300; 136 int ip_frags = 0; 137 138 /* from in_pcb.c */ 139 extern int ipport_firstauto; 140 extern int ipport_lastauto; 141 extern int ipport_hifirstauto; 142 extern int ipport_hilastauto; 143 extern struct baddynamicports baddynamicports; 144 145 extern struct domain inetdomain; 146 extern struct protosw inetsw[]; 147 u_char ip_protox[IPPROTO_MAX]; 148 int ipqmaxlen = IFQ_MAXLEN; 149 struct in_ifaddrhead in_ifaddr; 150 struct ifqueue ipintrq; 151 152 int ipq_locked; 153 static __inline int ipq_lock_try __P((void)); 154 static __inline void ipq_unlock __P((void)); 155 156 struct pool ipqent_pool; 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 sprintf(buf, "%d.%d.%d.%d", ucp[0] & 0xff, ucp[1] & 0xff, 193 ucp[2] & 0xff, ucp[3] & 0xff); 194 return (buf); 195 } 196 197 /* 198 * We need to save the IP options in case a protocol wants to respond 199 * to an incoming packet over the same route if the packet got here 200 * using IP source routing. This allows connection establishment and 201 * maintenance when the remote end is on a network that is not known 202 * to us. 203 */ 204 int ip_nhops = 0; 205 static struct ip_srcrt { 206 struct in_addr dst; /* final destination */ 207 char nop; /* one NOP to align */ 208 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 209 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 210 } ip_srcrt; 211 212 static void save_rte __P((u_char *, struct in_addr)); 213 static int ip_weadvertise(u_int32_t); 214 215 /* 216 * IP initialization: fill in IP protocol switch table. 217 * All protocols not implemented in kernel go to raw IP protocol handler. 218 */ 219 void 220 ip_init() 221 { 222 register struct protosw *pr; 223 register int i; 224 const u_int16_t defbaddynamicports_tcp[] = DEFBADDYNAMICPORTS_TCP; 225 const u_int16_t defbaddynamicports_udp[] = DEFBADDYNAMICPORTS_UDP; 226 227 pool_init(&ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl", 228 0, NULL, NULL, M_IPQ); 229 230 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 231 if (pr == 0) 232 panic("ip_init"); 233 for (i = 0; i < IPPROTO_MAX; i++) 234 ip_protox[i] = pr - inetsw; 235 for (pr = inetdomain.dom_protosw; 236 pr < inetdomain.dom_protoswNPROTOSW; pr++) 237 if (pr->pr_domain->dom_family == PF_INET && 238 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 239 ip_protox[pr->pr_protocol] = pr - inetsw; 240 LIST_INIT(&ipq); 241 ipintrq.ifq_maxlen = ipqmaxlen; 242 TAILQ_INIT(&in_ifaddr); 243 if (ip_mtudisc != 0) 244 ip_mtudisc_timeout_q = 245 rt_timer_queue_create(ip_mtudisc_timeout); 246 247 /* Fill in list of ports not to allocate dynamically. */ 248 bzero((void *)&baddynamicports, sizeof(baddynamicports)); 249 for (i = 0; defbaddynamicports_tcp[i] != 0; i++) 250 DP_SET(baddynamicports.tcp, defbaddynamicports_tcp[i]); 251 for (i = 0; defbaddynamicports_udp[i] != 0; i++) 252 DP_SET(baddynamicports.udp, defbaddynamicports_tcp[i]); 253 254 strncpy(ipsec_def_enc, IPSEC_DEFAULT_DEF_ENC, sizeof(ipsec_def_enc)); 255 strncpy(ipsec_def_auth, IPSEC_DEFAULT_DEF_AUTH, sizeof(ipsec_def_auth)); 256 strncpy(ipsec_def_comp, IPSEC_DEFAULT_DEF_COMP, sizeof(ipsec_def_comp)); 257 } 258 259 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 260 struct route ipforward_rt; 261 262 void 263 ipintr() 264 { 265 register struct mbuf *m; 266 int s; 267 268 if (needqueuedrain) 269 m_reclaim(); 270 271 while (1) { 272 /* 273 * Get next datagram off input queue and get IP header 274 * in first mbuf. 275 */ 276 s = splimp(); 277 IF_DEQUEUE(&ipintrq, m); 278 splx(s); 279 if (m == 0) 280 return; 281 #ifdef DIAGNOSTIC 282 if ((m->m_flags & M_PKTHDR) == 0) 283 panic("ipintr no HDR"); 284 #endif 285 ipv4_input(m); 286 } 287 } 288 289 /* 290 * Ip input routine. Checksum and byte swap header. If fragmented 291 * try to reassemble. Process options. Pass to next level. 292 */ 293 void 294 ipv4_input(m) 295 struct mbuf *m; 296 { 297 register struct ip *ip; 298 register struct ipq *fp; 299 struct in_ifaddr *ia; 300 struct ipqent *ipqe; 301 int hlen, mff; 302 #ifdef IPSEC 303 int error, s; 304 struct tdb *tdb; 305 struct tdb_ident *tdbi; 306 struct m_tag *mtag; 307 #endif /* IPSEC */ 308 309 /* 310 * If no IP addresses have been set yet but the interfaces 311 * are receiving, can't do anything with incoming packets yet. 312 */ 313 if (in_ifaddr.tqh_first == 0) 314 goto bad; 315 ipstat.ips_total++; 316 if (m->m_len < sizeof (struct ip) && 317 (m = m_pullup(m, sizeof (struct ip))) == NULL) { 318 ipstat.ips_toosmall++; 319 return; 320 } 321 ip = mtod(m, struct ip *); 322 if (ip->ip_v != IPVERSION) { 323 ipstat.ips_badvers++; 324 goto bad; 325 } 326 hlen = ip->ip_hl << 2; 327 if (hlen < sizeof(struct ip)) { /* minimum header length */ 328 ipstat.ips_badhlen++; 329 goto bad; 330 } 331 if (hlen > m->m_len) { 332 if ((m = m_pullup(m, hlen)) == NULL) { 333 ipstat.ips_badhlen++; 334 return; 335 } 336 ip = mtod(m, struct ip *); 337 } 338 339 /* 127/8 must not appear on wire - RFC1122 */ 340 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 341 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 342 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) { 343 ipstat.ips_badaddr++; 344 goto bad; 345 } 346 } 347 348 if ((m->m_pkthdr.csum & M_IPV4_CSUM_IN_OK) == 0) { 349 if (m->m_pkthdr.csum & M_IPV4_CSUM_IN_BAD) { 350 ipstat.ips_inhwcsum++; 351 ipstat.ips_badsum++; 352 goto bad; 353 } 354 355 if (in_cksum(m, hlen) != 0) { 356 ipstat.ips_badsum++; 357 goto bad; 358 } 359 } else { 360 m->m_pkthdr.csum &= ~M_IPV4_CSUM_IN_OK; 361 ipstat.ips_inhwcsum++; 362 } 363 364 /* 365 * Convert fields to host representation. 366 */ 367 NTOHS(ip->ip_len); 368 if (ip->ip_len < hlen) { 369 ipstat.ips_badlen++; 370 goto bad; 371 } 372 NTOHS(ip->ip_off); 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 < ip->ip_len) { 381 ipstat.ips_tooshort++; 382 goto bad; 383 } 384 if (m->m_pkthdr.len > ip->ip_len) { 385 if (m->m_len == m->m_pkthdr.len) { 386 m->m_len = ip->ip_len; 387 m->m_pkthdr.len = ip->ip_len; 388 } else 389 m_adj(m, ip->ip_len - m->m_pkthdr.len); 390 } 391 392 #if NPF > 0 393 /* 394 * Packet filter 395 */ 396 if (pf_test(PF_IN, m->m_pkthdr.rcvif, &m) != PF_PASS) 397 goto bad; 398 if (m == NULL) 399 return; 400 401 ip = mtod(m, struct ip *); 402 hlen = ip->ip_hl << 2; 403 #endif 404 405 #ifdef ALTQ 406 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 407 /* packet is dropped by traffic conditioner */ 408 return; 409 #endif 410 411 /* 412 * Process options and, if not destined for us, 413 * ship it on. ip_dooptions returns 1 when an 414 * error was detected (causing an icmp message 415 * to be sent and the original packet to be freed). 416 */ 417 ip_nhops = 0; /* for source routed packets */ 418 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 419 return; 420 } 421 422 /* 423 * Check our list of addresses, to see if the packet is for us. 424 */ 425 if ((ia = in_iawithaddr(ip->ip_dst, m)) != NULL && 426 (ia->ia_ifp->if_flags & IFF_UP)) 427 goto ours; 428 429 if (IN_MULTICAST(ip->ip_dst.s_addr)) { 430 struct in_multi *inm; 431 #ifdef MROUTING 432 extern struct socket *ip_mrouter; 433 434 if (m->m_flags & M_EXT) { 435 if ((m = m_pullup(m, hlen)) == NULL) { 436 ipstat.ips_toosmall++; 437 return; 438 } 439 ip = mtod(m, struct ip *); 440 } 441 442 if (ip_mrouter) { 443 /* 444 * If we are acting as a multicast router, all 445 * incoming multicast packets are passed to the 446 * kernel-level multicast forwarding function. 447 * The packet is returned (relatively) intact; if 448 * ip_mforward() returns a non-zero value, the packet 449 * must be discarded, else it may be accepted below. 450 * 451 * (The IP ident field is put in the same byte order 452 * as expected when ip_mforward() is called from 453 * ip_output().) 454 */ 455 if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) { 456 ipstat.ips_cantforward++; 457 m_freem(m); 458 return; 459 } 460 461 /* 462 * The process-level routing demon needs to receive 463 * all multicast IGMP packets, whether or not this 464 * host belongs to their destination groups. 465 */ 466 if (ip->ip_p == IPPROTO_IGMP) 467 goto ours; 468 ipstat.ips_forward++; 469 } 470 #endif 471 /* 472 * See if we belong to the destination multicast group on the 473 * arrival interface. 474 */ 475 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 476 if (inm == NULL) { 477 ipstat.ips_cantforward++; 478 m_freem(m); 479 return; 480 } 481 goto ours; 482 } 483 if (ip->ip_dst.s_addr == INADDR_BROADCAST || 484 ip->ip_dst.s_addr == INADDR_ANY) 485 goto ours; 486 487 /* 488 * Not for us; forward if possible and desirable. 489 */ 490 if (ipforwarding == 0) { 491 ipstat.ips_cantforward++; 492 m_freem(m); 493 } else { 494 #ifdef IPSEC 495 /* IPsec policy check for forwarded packets */ 496 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 497 s = splnet(); 498 if (mtag != NULL) { 499 tdbi = (struct tdb_ident *)(mtag + 1); 500 tdb = gettdb(tdbi->spi, &tdbi->dst, tdbi->proto); 501 } else 502 tdb = NULL; 503 ipsp_spd_lookup(m, AF_INET, hlen, &error, 504 IPSP_DIRECTION_IN, tdb, NULL); 505 splx(s); 506 507 /* Error or otherwise drop-packet indication */ 508 if (error) { 509 ipstat.ips_cantforward++; 510 m_freem(m); 511 return; 512 } 513 514 /* Fall through, forward packet */ 515 #endif /* IPSEC */ 516 517 ip_forward(m, 0); 518 } 519 return; 520 521 ours: 522 /* 523 * If offset or IP_MF are set, must reassemble. 524 * Otherwise, nothing need be done. 525 * (We could look in the reassembly queue to see 526 * if the packet was previously fragmented, 527 * but it's not worth the time; just let them time out.) 528 */ 529 if (ip->ip_off &~ (IP_DF | IP_RF)) { 530 if (m->m_flags & M_EXT) { /* XXX */ 531 if ((m = m_pullup(m, hlen)) == NULL) { 532 ipstat.ips_toosmall++; 533 return; 534 } 535 ip = mtod(m, struct ip *); 536 } 537 538 /* 539 * Look for queue of fragments 540 * of this datagram. 541 */ 542 ipq_lock(); 543 for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next) 544 if (ip->ip_id == fp->ipq_id && 545 ip->ip_src.s_addr == fp->ipq_src.s_addr && 546 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 547 ip->ip_p == fp->ipq_p) 548 goto found; 549 fp = 0; 550 found: 551 552 /* 553 * Adjust ip_len to not reflect header, 554 * set ipqe_mff if more fragments are expected, 555 * convert offset of this to bytes. 556 */ 557 ip->ip_len -= hlen; 558 mff = (ip->ip_off & IP_MF) != 0; 559 if (mff) { 560 /* 561 * Make sure that fragments have a data length 562 * that's a non-zero multiple of 8 bytes. 563 */ 564 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 565 ipstat.ips_badfrags++; 566 ipq_unlock(); 567 goto bad; 568 } 569 } 570 ip->ip_off <<= 3; 571 572 /* 573 * If datagram marked as having more fragments 574 * or if this is not the first fragment, 575 * attempt reassembly; if it succeeds, proceed. 576 */ 577 if (mff || ip->ip_off) { 578 ipstat.ips_fragments++; 579 if (ip_frags + 1 > ip_maxqueue) { 580 ip_flush(); 581 ipstat.ips_rcvmemdrop++; 582 ipq_unlock(); 583 goto bad; 584 } 585 586 ipqe = pool_get(&ipqent_pool, PR_NOWAIT); 587 if (ipqe == NULL) { 588 ipstat.ips_rcvmemdrop++; 589 ipq_unlock(); 590 goto bad; 591 } 592 ip_frags++; 593 ipqe->ipqe_mff = mff; 594 ipqe->ipqe_m = m; 595 ipqe->ipqe_ip = ip; 596 m = ip_reass(ipqe, fp); 597 if (m == 0) { 598 ipq_unlock(); 599 return; 600 } 601 ipstat.ips_reassembled++; 602 ip = mtod(m, struct ip *); 603 hlen = ip->ip_hl << 2; 604 } else 605 if (fp) 606 ip_freef(fp); 607 ipq_unlock(); 608 } else 609 ip->ip_len -= hlen; 610 611 #ifdef IPSEC 612 /* 613 * If it's a protected packet for us, skip the policy check. 614 * That's because we really only care about the properties of 615 * the protected packet, and not the intermediate versions. 616 * While this is not the most paranoid setting, it allows 617 * some flexibility in handling of nested tunnels etc. 618 */ 619 if ((ip->ip_p == IPPROTO_ESP) || (ip->ip_p == IPPROTO_AH) || 620 (ip->ip_p == IPPROTO_IPCOMP)) 621 goto skipipsec; 622 623 /* 624 * If the protected packet was tunneled, then we need to 625 * verify the protected packet's information, not the 626 * external headers. Thus, skip the policy lookup for the 627 * external packet, and keep the IPsec information linked on 628 * the packet header (the encapsulation routines know how 629 * to deal with that). 630 */ 631 if ((ip->ip_p == IPPROTO_IPIP) || (ip->ip_p == IPPROTO_IPV6)) 632 goto skipipsec; 633 634 /* 635 * If the protected packet is TCP or UDP, we'll do the 636 * policy check in the respective input routine, so we can 637 * check for bypass sockets. 638 */ 639 if ((ip->ip_p == IPPROTO_TCP) || (ip->ip_p == IPPROTO_UDP)) 640 goto skipipsec; 641 642 /* IPsec policy check for local-delivery packets */ 643 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL); 644 s = splnet(); 645 if (mtag) { 646 tdbi = (struct tdb_ident *)(mtag + 1); 647 tdb = gettdb(tdbi->spi, &tdbi->dst, tdbi->proto); 648 } else 649 tdb = NULL; 650 ipsp_spd_lookup(m, AF_INET, hlen, &error, IPSP_DIRECTION_IN, 651 tdb, NULL); 652 splx(s); 653 654 /* Error or otherwise drop-packet indication */ 655 if (error) { 656 ipstat.ips_cantforward++; 657 m_freem(m); 658 return; 659 } 660 661 skipipsec: 662 /* Otherwise, just fall through and deliver the packet */ 663 #endif /* IPSEC */ 664 665 /* 666 * Switch out to protocol's input routine. 667 */ 668 ipstat.ips_delivered++; 669 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen, NULL, 0); 670 return; 671 bad: 672 m_freem(m); 673 } 674 675 struct in_ifaddr * 676 in_iawithaddr(ina, m) 677 struct in_addr ina; 678 register struct mbuf *m; 679 { 680 register struct in_ifaddr *ia; 681 682 for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) { 683 if ((ina.s_addr == ia->ia_addr.sin_addr.s_addr) || 684 ((ia->ia_ifp->if_flags & (IFF_LOOPBACK|IFF_LINK1)) == 685 (IFF_LOOPBACK|IFF_LINK1) && 686 ia->ia_subnet == (ina.s_addr & ia->ia_subnetmask))) 687 return ia; 688 if (((ip_directedbcast == 0) || (m && ip_directedbcast && 689 ia->ia_ifp == m->m_pkthdr.rcvif)) && 690 (ia->ia_ifp->if_flags & IFF_BROADCAST)) { 691 if (ina.s_addr == ia->ia_broadaddr.sin_addr.s_addr || 692 ina.s_addr == ia->ia_netbroadcast.s_addr || 693 /* 694 * Look for all-0's host part (old broadcast addr), 695 * either for subnet or net. 696 */ 697 ina.s_addr == ia->ia_subnet || 698 ina.s_addr == ia->ia_net) { 699 /* Make sure M_BCAST is set */ 700 if (m) 701 m->m_flags |= M_BCAST; 702 return ia; 703 } 704 } 705 } 706 707 return NULL; 708 } 709 710 /* 711 * Take incoming datagram fragment and try to 712 * reassemble it into whole datagram. If a chain for 713 * reassembly of this datagram already exists, then it 714 * is given as fp; otherwise have to make a chain. 715 */ 716 struct mbuf * 717 ip_reass(ipqe, fp) 718 struct ipqent *ipqe; 719 struct ipq *fp; 720 { 721 struct mbuf *m = ipqe->ipqe_m; 722 struct ipqent *nq, *p, *q; 723 struct ip *ip; 724 struct mbuf *t; 725 int hlen = ipqe->ipqe_ip->ip_hl << 2; 726 int i, next; 727 728 /* 729 * Presence of header sizes in mbufs 730 * would confuse code below. 731 */ 732 m->m_data += hlen; 733 m->m_len -= hlen; 734 735 /* 736 * If first fragment to arrive, create a reassembly queue. 737 */ 738 if (fp == 0) { 739 MALLOC(fp, struct ipq *, sizeof (struct ipq), 740 M_FTABLE, M_NOWAIT); 741 if (fp == NULL) 742 goto dropfrag; 743 LIST_INSERT_HEAD(&ipq, fp, ipq_q); 744 fp->ipq_ttl = IPFRAGTTL; 745 fp->ipq_p = ipqe->ipqe_ip->ip_p; 746 fp->ipq_id = ipqe->ipqe_ip->ip_id; 747 LIST_INIT(&fp->ipq_fragq); 748 fp->ipq_src = ipqe->ipqe_ip->ip_src; 749 fp->ipq_dst = ipqe->ipqe_ip->ip_dst; 750 p = NULL; 751 goto insert; 752 } 753 754 /* 755 * Find a segment which begins after this one does. 756 */ 757 for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL; 758 p = q, q = q->ipqe_q.le_next) 759 if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off) 760 break; 761 762 /* 763 * If there is a preceding segment, it may provide some of 764 * our data already. If so, drop the data from the incoming 765 * segment. If it provides all of our data, drop us. 766 */ 767 if (p != NULL) { 768 i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len - 769 ipqe->ipqe_ip->ip_off; 770 if (i > 0) { 771 if (i >= ipqe->ipqe_ip->ip_len) 772 goto dropfrag; 773 m_adj(ipqe->ipqe_m, i); 774 ipqe->ipqe_ip->ip_off += i; 775 ipqe->ipqe_ip->ip_len -= i; 776 } 777 } 778 779 /* 780 * While we overlap succeeding segments trim them or, 781 * if they are completely covered, dequeue them. 782 */ 783 for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len > 784 q->ipqe_ip->ip_off; q = nq) { 785 i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) - 786 q->ipqe_ip->ip_off; 787 if (i < q->ipqe_ip->ip_len) { 788 q->ipqe_ip->ip_len -= i; 789 q->ipqe_ip->ip_off += i; 790 m_adj(q->ipqe_m, i); 791 break; 792 } 793 nq = q->ipqe_q.le_next; 794 m_freem(q->ipqe_m); 795 LIST_REMOVE(q, ipqe_q); 796 pool_put(&ipqent_pool, q); 797 ip_frags--; 798 } 799 800 insert: 801 /* 802 * Stick new segment in its place; 803 * check for complete reassembly. 804 */ 805 if (p == NULL) { 806 LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); 807 } else { 808 LIST_INSERT_AFTER(p, ipqe, ipqe_q); 809 } 810 next = 0; 811 for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL; 812 p = q, q = q->ipqe_q.le_next) { 813 if (q->ipqe_ip->ip_off != next) 814 return (0); 815 next += q->ipqe_ip->ip_len; 816 } 817 if (p->ipqe_mff) 818 return (0); 819 820 /* 821 * Reassembly is complete. Check for a bogus message size and 822 * concatenate fragments. 823 */ 824 q = fp->ipq_fragq.lh_first; 825 ip = q->ipqe_ip; 826 if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) { 827 ipstat.ips_toolong++; 828 ip_freef(fp); 829 return (0); 830 } 831 m = q->ipqe_m; 832 t = m->m_next; 833 m->m_next = 0; 834 m_cat(m, t); 835 nq = q->ipqe_q.le_next; 836 pool_put(&ipqent_pool, q); 837 ip_frags--; 838 for (q = nq; q != NULL; q = nq) { 839 t = q->ipqe_m; 840 nq = q->ipqe_q.le_next; 841 pool_put(&ipqent_pool, q); 842 ip_frags--; 843 m_cat(m, t); 844 } 845 846 /* 847 * Create header for new ip packet by 848 * modifying header of first packet; 849 * dequeue and discard fragment reassembly header. 850 * Make header visible. 851 */ 852 ip->ip_len = next; 853 ip->ip_src = fp->ipq_src; 854 ip->ip_dst = fp->ipq_dst; 855 LIST_REMOVE(fp, ipq_q); 856 FREE(fp, M_FTABLE); 857 m->m_len += (ip->ip_hl << 2); 858 m->m_data -= (ip->ip_hl << 2); 859 /* some debugging cruft by sklower, below, will go away soon */ 860 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 861 int plen = 0; 862 for (t = m; t; t = t->m_next) 863 plen += t->m_len; 864 m->m_pkthdr.len = plen; 865 } 866 return (m); 867 868 dropfrag: 869 ipstat.ips_fragdropped++; 870 m_freem(m); 871 pool_put(&ipqent_pool, ipqe); 872 ip_frags--; 873 return (0); 874 } 875 876 /* 877 * Free a fragment reassembly header and all 878 * associated datagrams. 879 */ 880 void 881 ip_freef(fp) 882 struct ipq *fp; 883 { 884 register struct ipqent *q, *p; 885 886 for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) { 887 p = q->ipqe_q.le_next; 888 m_freem(q->ipqe_m); 889 LIST_REMOVE(q, ipqe_q); 890 pool_put(&ipqent_pool, q); 891 ip_frags--; 892 } 893 LIST_REMOVE(fp, ipq_q); 894 FREE(fp, M_FTABLE); 895 } 896 897 /* 898 * IP timer processing; 899 * if a timer expires on a reassembly 900 * queue, discard it. 901 */ 902 void 903 ip_slowtimo() 904 { 905 register struct ipq *fp, *nfp; 906 int s = splsoftnet(); 907 908 ipq_lock(); 909 for (fp = ipq.lh_first; fp != NULL; fp = nfp) { 910 nfp = fp->ipq_q.le_next; 911 if (--fp->ipq_ttl == 0) { 912 ipstat.ips_fragtimeout++; 913 ip_freef(fp); 914 } 915 } 916 ipq_unlock(); 917 splx(s); 918 } 919 920 /* 921 * Drain off all datagram fragments. 922 */ 923 void 924 ip_drain() 925 { 926 927 if (ipq_lock_try() == 0) 928 return; 929 while (ipq.lh_first != NULL) { 930 ipstat.ips_fragdropped++; 931 ip_freef(ipq.lh_first); 932 } 933 ipq_unlock(); 934 } 935 936 /* 937 * Flush a bunch of datagram fragments, till we are down to 75%. 938 */ 939 void 940 ip_flush() 941 { 942 int max = 50; 943 944 /* ipq already locked */ 945 while (ipq.lh_first != NULL && ip_frags > ip_maxqueue * 3 / 4 && --max) { 946 ipstat.ips_fragdropped++; 947 ip_freef(ipq.lh_first); 948 } 949 } 950 951 /* 952 * Do option processing on a datagram, 953 * possibly discarding it if bad options are encountered, 954 * or forwarding it if source-routed. 955 * Returns 1 if packet has been forwarded/freed, 956 * 0 if the packet should be processed further. 957 */ 958 int 959 ip_dooptions(m) 960 struct mbuf *m; 961 { 962 register struct ip *ip = mtod(m, struct ip *); 963 register u_char *cp; 964 struct ip_timestamp ipt; 965 register struct in_ifaddr *ia; 966 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 967 struct in_addr sin, dst; 968 n_time ntime; 969 970 dst = ip->ip_dst; 971 cp = (u_char *)(ip + 1); 972 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 973 974 for (; cnt > 0; cnt -= optlen, cp += optlen) { 975 opt = cp[IPOPT_OPTVAL]; 976 if (opt == IPOPT_EOL) 977 break; 978 if (opt == IPOPT_NOP) 979 optlen = 1; 980 else { 981 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 982 code = &cp[IPOPT_OLEN] - (u_char *)ip; 983 goto bad; 984 } 985 optlen = cp[IPOPT_OLEN]; 986 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 987 code = &cp[IPOPT_OLEN] - (u_char *)ip; 988 goto bad; 989 } 990 } 991 992 switch (opt) { 993 994 default: 995 break; 996 997 /* 998 * Source routing with record. 999 * Find interface with current destination address. 1000 * If none on this machine then drop if strictly routed, 1001 * or do nothing if loosely routed. 1002 * Record interface address and bring up next address 1003 * component. If strictly routed make sure next 1004 * address is on directly accessible net. 1005 */ 1006 case IPOPT_LSRR: 1007 case IPOPT_SSRR: 1008 if (!ip_dosourceroute) { 1009 char buf[4*sizeof "123"]; 1010 1011 strcpy(buf, inet_ntoa(ip->ip_dst)); 1012 log(LOG_WARNING, 1013 "attempted source route from %s to %s\n", 1014 inet_ntoa(ip->ip_src), buf); 1015 type = ICMP_UNREACH; 1016 code = ICMP_UNREACH_SRCFAIL; 1017 goto bad; 1018 } 1019 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1020 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1021 goto bad; 1022 } 1023 ipaddr.sin_addr = ip->ip_dst; 1024 ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); 1025 if (ia == 0) { 1026 if (opt == IPOPT_SSRR) { 1027 type = ICMP_UNREACH; 1028 code = ICMP_UNREACH_SRCFAIL; 1029 goto bad; 1030 } 1031 /* 1032 * Loose routing, and not at next destination 1033 * yet; nothing to do except forward. 1034 */ 1035 break; 1036 } 1037 off--; /* 0 origin */ 1038 if ((off + sizeof(struct in_addr)) > optlen) { 1039 /* 1040 * End of source route. Should be for us. 1041 */ 1042 save_rte(cp, ip->ip_src); 1043 break; 1044 } 1045 1046 /* 1047 * locate outgoing interface 1048 */ 1049 bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr, 1050 sizeof(ipaddr.sin_addr)); 1051 if (opt == IPOPT_SSRR) { 1052 #define INA struct in_ifaddr * 1053 #define SA struct sockaddr * 1054 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1055 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1056 } else 1057 ia = ip_rtaddr(ipaddr.sin_addr); 1058 if (ia == 0) { 1059 type = ICMP_UNREACH; 1060 code = ICMP_UNREACH_SRCFAIL; 1061 goto bad; 1062 } 1063 ip->ip_dst = ipaddr.sin_addr; 1064 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1065 (caddr_t)(cp + off), sizeof(struct in_addr)); 1066 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1067 /* 1068 * Let ip_intr's mcast routing check handle mcast pkts 1069 */ 1070 forward = !IN_MULTICAST(ip->ip_dst.s_addr); 1071 break; 1072 1073 case IPOPT_RR: 1074 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 1075 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1076 goto bad; 1077 } 1078 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1079 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1080 goto bad; 1081 } 1082 1083 /* 1084 * If no space remains, ignore. 1085 */ 1086 off--; /* 0 origin */ 1087 if ((off + sizeof(struct in_addr)) > optlen) 1088 break; 1089 bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr, 1090 sizeof(ipaddr.sin_addr)); 1091 /* 1092 * locate outgoing interface; if we're the destination, 1093 * use the incoming interface (should be same). 1094 */ 1095 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1096 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1097 type = ICMP_UNREACH; 1098 code = ICMP_UNREACH_HOST; 1099 goto bad; 1100 } 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 break; 1105 1106 case IPOPT_TS: 1107 code = cp - (u_char *)ip; 1108 bcopy(cp, &ipt, sizeof(struct ip_timestamp)); 1109 if (ipt.ipt_ptr < 5 || ipt.ipt_len < 5) 1110 goto bad; 1111 if (ipt.ipt_ptr - 1 + sizeof(n_time) > ipt.ipt_len) { 1112 if (++ipt.ipt_oflw == 0) 1113 goto bad; 1114 break; 1115 } 1116 bcopy(cp + ipt.ipt_ptr - 1, &sin, sizeof sin); 1117 switch (ipt.ipt_flg) { 1118 1119 case IPOPT_TS_TSONLY: 1120 break; 1121 1122 case IPOPT_TS_TSANDADDR: 1123 if (ipt.ipt_ptr - 1 + sizeof(n_time) + 1124 sizeof(struct in_addr) > ipt.ipt_len) 1125 goto bad; 1126 ipaddr.sin_addr = dst; 1127 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1128 m->m_pkthdr.rcvif); 1129 if (ia == 0) 1130 continue; 1131 bcopy((caddr_t)&ia->ia_addr.sin_addr, 1132 (caddr_t)&sin, sizeof(struct in_addr)); 1133 ipt.ipt_ptr += sizeof(struct in_addr); 1134 break; 1135 1136 case IPOPT_TS_PRESPEC: 1137 if (ipt.ipt_ptr - 1 + sizeof(n_time) + 1138 sizeof(struct in_addr) > ipt.ipt_len) 1139 goto bad; 1140 bcopy((caddr_t)&sin, (caddr_t)&ipaddr.sin_addr, 1141 sizeof(struct in_addr)); 1142 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1143 continue; 1144 ipt.ipt_ptr += sizeof(struct in_addr); 1145 break; 1146 1147 default: 1148 /* XXX can't take &ipt->ipt_flg */ 1149 code = (u_char *)&ipt.ipt_ptr - 1150 (u_char *)ip + 1; 1151 goto bad; 1152 } 1153 ntime = iptime(); 1154 bcopy((caddr_t)&ntime, (caddr_t)cp + ipt.ipt_ptr - 1, 1155 sizeof(n_time)); 1156 ipt.ipt_ptr += sizeof(n_time); 1157 } 1158 } 1159 if (forward && ipforwarding) { 1160 ip_forward(m, 1); 1161 return (1); 1162 } 1163 return (0); 1164 bad: 1165 ip->ip_len -= ip->ip_hl << 2; /* XXX icmp_error adds in hdr length */ 1166 icmp_error(m, type, code, 0, 0); 1167 ipstat.ips_badoptions++; 1168 return (1); 1169 } 1170 1171 /* 1172 * Given address of next destination (final or next hop), 1173 * return internet address info of interface to be used to get there. 1174 */ 1175 struct in_ifaddr * 1176 ip_rtaddr(dst) 1177 struct in_addr dst; 1178 { 1179 register struct sockaddr_in *sin; 1180 1181 sin = satosin(&ipforward_rt.ro_dst); 1182 1183 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 1184 if (ipforward_rt.ro_rt) { 1185 RTFREE(ipforward_rt.ro_rt); 1186 ipforward_rt.ro_rt = 0; 1187 } 1188 sin->sin_family = AF_INET; 1189 sin->sin_len = sizeof(*sin); 1190 sin->sin_addr = dst; 1191 1192 rtalloc(&ipforward_rt); 1193 } 1194 if (ipforward_rt.ro_rt == 0) 1195 return ((struct in_ifaddr *)0); 1196 return (ifatoia(ipforward_rt.ro_rt->rt_ifa)); 1197 } 1198 1199 /* 1200 * Save incoming source route for use in replies, 1201 * to be picked up later by ip_srcroute if the receiver is interested. 1202 */ 1203 void 1204 save_rte(option, dst) 1205 u_char *option; 1206 struct in_addr dst; 1207 { 1208 unsigned olen; 1209 1210 olen = option[IPOPT_OLEN]; 1211 #ifdef DIAGNOSTIC 1212 if (ipprintfs) 1213 printf("save_rte: olen %d\n", olen); 1214 #endif /* 0 */ 1215 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1216 return; 1217 bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen); 1218 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1219 ip_srcrt.dst = dst; 1220 } 1221 1222 /* 1223 * Check whether we do proxy ARP for this address and we point to ourselves. 1224 * Code shamelessly copied from arplookup(). 1225 */ 1226 static int 1227 ip_weadvertise(addr) 1228 u_int32_t addr; 1229 { 1230 register struct rtentry *rt; 1231 register struct ifnet *ifp; 1232 register struct ifaddr *ifa; 1233 struct sockaddr_inarp sin; 1234 1235 sin.sin_len = sizeof(sin); 1236 sin.sin_family = AF_INET; 1237 sin.sin_addr.s_addr = addr; 1238 sin.sin_other = SIN_PROXY; 1239 rt = rtalloc1(sintosa(&sin), 0); 1240 if (rt == 0) 1241 return 0; 1242 1243 RTFREE(rt); 1244 1245 if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || 1246 rt->rt_gateway->sa_family != AF_LINK) { 1247 RTFREE(rt); 1248 return 0; 1249 } 1250 1251 for (ifp = ifnet.tqh_first; ifp != 0; ifp = ifp->if_list.tqe_next) 1252 for (ifa = ifp->if_addrlist.tqh_first; ifa != 0; 1253 ifa = ifa->ifa_list.tqe_next) { 1254 if (ifa->ifa_addr->sa_family != rt->rt_gateway->sa_family) 1255 continue; 1256 1257 if (!bcmp(LLADDR((struct sockaddr_dl *)ifa->ifa_addr), 1258 LLADDR((struct sockaddr_dl *)rt->rt_gateway), 1259 ETHER_ADDR_LEN)) { 1260 RTFREE(rt); 1261 return 1; 1262 } 1263 } 1264 1265 RTFREE(rt); 1266 return 0; 1267 } 1268 1269 /* 1270 * Retrieve incoming source route for use in replies, 1271 * in the same form used by setsockopt. 1272 * The first hop is placed before the options, will be removed later. 1273 */ 1274 struct mbuf * 1275 ip_srcroute() 1276 { 1277 register struct in_addr *p, *q; 1278 register struct mbuf *m; 1279 1280 if (ip_nhops == 0) 1281 return ((struct mbuf *)0); 1282 m = m_get(M_DONTWAIT, MT_SOOPTS); 1283 if (m == 0) 1284 return ((struct mbuf *)0); 1285 1286 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1287 1288 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1289 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1290 OPTSIZ; 1291 #ifdef DIAGNOSTIC 1292 if (ipprintfs) 1293 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1294 #endif 1295 1296 /* 1297 * First save first hop for return route 1298 */ 1299 p = &ip_srcrt.route[ip_nhops - 1]; 1300 *(mtod(m, struct in_addr *)) = *p--; 1301 #ifdef DIAGNOSTIC 1302 if (ipprintfs) 1303 printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr)); 1304 #endif 1305 1306 /* 1307 * Copy option fields and padding (nop) to mbuf. 1308 */ 1309 ip_srcrt.nop = IPOPT_NOP; 1310 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1311 bcopy((caddr_t)&ip_srcrt.nop, 1312 mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ); 1313 q = (struct in_addr *)(mtod(m, caddr_t) + 1314 sizeof(struct in_addr) + OPTSIZ); 1315 #undef OPTSIZ 1316 /* 1317 * Record return path as an IP source route, 1318 * reversing the path (pointers are now aligned). 1319 */ 1320 while (p >= ip_srcrt.route) { 1321 #ifdef DIAGNOSTIC 1322 if (ipprintfs) 1323 printf(" %x", ntohl(q->s_addr)); 1324 #endif 1325 *q++ = *p--; 1326 } 1327 /* 1328 * Last hop goes to final destination. 1329 */ 1330 *q = ip_srcrt.dst; 1331 #ifdef DIAGNOSTIC 1332 if (ipprintfs) 1333 printf(" %x\n", ntohl(q->s_addr)); 1334 #endif 1335 return (m); 1336 } 1337 1338 /* 1339 * Strip out IP options, at higher 1340 * level protocol in the kernel. 1341 * Second argument is buffer to which options 1342 * will be moved, and return value is their length. 1343 * XXX should be deleted; last arg currently ignored. 1344 */ 1345 void 1346 ip_stripoptions(m, mopt) 1347 register struct mbuf *m; 1348 struct mbuf *mopt; 1349 { 1350 register int i; 1351 struct ip *ip = mtod(m, struct ip *); 1352 register caddr_t opts; 1353 int olen; 1354 1355 olen = (ip->ip_hl<<2) - sizeof (struct ip); 1356 opts = (caddr_t)(ip + 1); 1357 i = m->m_len - (sizeof (struct ip) + olen); 1358 bcopy(opts + olen, opts, (unsigned)i); 1359 m->m_len -= olen; 1360 if (m->m_flags & M_PKTHDR) 1361 m->m_pkthdr.len -= olen; 1362 ip->ip_hl = sizeof(struct ip) >> 2; 1363 } 1364 1365 int inetctlerrmap[PRC_NCMDS] = { 1366 0, 0, 0, 0, 1367 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1368 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1369 EMSGSIZE, EHOSTUNREACH, 0, 0, 1370 0, 0, 0, 0, 1371 ENOPROTOOPT 1372 }; 1373 1374 /* 1375 * Forward a packet. If some error occurs return the sender 1376 * an icmp packet. Note we can't always generate a meaningful 1377 * icmp message because icmp doesn't have a large enough repertoire 1378 * of codes and types. 1379 * 1380 * If not forwarding, just drop the packet. This could be confusing 1381 * if ipforwarding was zero but some routing protocol was advancing 1382 * us as a gateway to somewhere. However, we must let the routing 1383 * protocol deal with that. 1384 * 1385 * The srcrt parameter indicates whether the packet is being forwarded 1386 * via a source route. 1387 */ 1388 void 1389 ip_forward(m, srcrt) 1390 struct mbuf *m; 1391 int srcrt; 1392 { 1393 register struct ip *ip = mtod(m, struct ip *); 1394 register struct sockaddr_in *sin; 1395 register struct rtentry *rt; 1396 int error, type = 0, code = 0; 1397 struct mbuf *mcopy; 1398 n_long dest; 1399 struct ifnet *destifp; 1400 #ifdef IPSEC 1401 struct ifnet dummyifp; 1402 #endif 1403 1404 dest = 0; 1405 #ifdef DIAGNOSTIC 1406 if (ipprintfs) 1407 printf("forward: src %x dst %x ttl %x\n", ip->ip_src.s_addr, 1408 ip->ip_dst.s_addr, ip->ip_ttl); 1409 #endif 1410 if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) { 1411 ipstat.ips_cantforward++; 1412 m_freem(m); 1413 return; 1414 } 1415 if (ip->ip_ttl <= IPTTLDEC) { 1416 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); 1417 return; 1418 } 1419 ip->ip_ttl -= IPTTLDEC; 1420 1421 sin = satosin(&ipforward_rt.ro_dst); 1422 if ((rt = ipforward_rt.ro_rt) == 0 || 1423 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1424 if (ipforward_rt.ro_rt) { 1425 RTFREE(ipforward_rt.ro_rt); 1426 ipforward_rt.ro_rt = 0; 1427 } 1428 sin->sin_family = AF_INET; 1429 sin->sin_len = sizeof(*sin); 1430 sin->sin_addr = ip->ip_dst; 1431 1432 rtalloc(&ipforward_rt); 1433 if (ipforward_rt.ro_rt == 0) { 1434 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1435 return; 1436 } 1437 rt = ipforward_rt.ro_rt; 1438 } 1439 1440 /* 1441 * Save at most 68 bytes of the packet in case 1442 * we need to generate an ICMP message to the src. 1443 * Pullup to avoid sharing mbuf cluster between m and mcopy. 1444 */ 1445 mcopy = m_copym(m, 0, imin((int)ip->ip_len, 68), M_DONTWAIT); 1446 if (mcopy) 1447 mcopy = m_pullup(mcopy, ip->ip_hl << 2); 1448 1449 /* 1450 * If forwarding packet using same interface that it came in on, 1451 * perhaps should send a redirect to sender to shortcut a hop. 1452 * Only send redirect if source is sending directly to us, 1453 * and if packet was not source routed (or has any options). 1454 * Also, don't send redirect if forwarding using a default route 1455 * or a route modified by a redirect. 1456 * Don't send redirect if we advertise destination's arp address 1457 * as ours (proxy arp). 1458 */ 1459 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1460 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1461 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1462 ipsendredirects && !srcrt && 1463 !ip_weadvertise(satosin(rt_key(rt))->sin_addr.s_addr)) { 1464 if (rt->rt_ifa && 1465 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == 1466 ifatoia(rt->rt_ifa)->ia_subnet) { 1467 if (rt->rt_flags & RTF_GATEWAY) 1468 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1469 else 1470 dest = ip->ip_dst.s_addr; 1471 /* Router requirements says to only send host redirects */ 1472 type = ICMP_REDIRECT; 1473 code = ICMP_REDIRECT_HOST; 1474 #ifdef DIAGNOSTIC 1475 if (ipprintfs) 1476 printf("redirect (%d) to %x\n", code, (u_int32_t)dest); 1477 #endif 1478 } 1479 } 1480 1481 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1482 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 1483 0, NULL, NULL); 1484 if (error) 1485 ipstat.ips_cantforward++; 1486 else { 1487 ipstat.ips_forward++; 1488 if (type) 1489 ipstat.ips_redirectsent++; 1490 else { 1491 if (mcopy) 1492 m_freem(mcopy); 1493 return; 1494 } 1495 } 1496 if (mcopy == NULL) 1497 return; 1498 destifp = NULL; 1499 1500 switch (error) { 1501 1502 case 0: /* forwarded, but need redirect */ 1503 /* type, code set above */ 1504 break; 1505 1506 case ENETUNREACH: /* shouldn't happen, checked above */ 1507 case EHOSTUNREACH: 1508 case ENETDOWN: 1509 case EHOSTDOWN: 1510 default: 1511 type = ICMP_UNREACH; 1512 code = ICMP_UNREACH_HOST; 1513 break; 1514 1515 case EMSGSIZE: 1516 type = ICMP_UNREACH; 1517 code = ICMP_UNREACH_NEEDFRAG; 1518 1519 #ifdef IPSEC 1520 if (ipforward_rt.ro_rt) { 1521 struct rtentry *rt = ipforward_rt.ro_rt; 1522 destifp = ipforward_rt.ro_rt->rt_ifp; 1523 /* 1524 * XXX BUG ALERT 1525 * The "dummyifp" code relies upon the fact 1526 * that icmp_error() touches only ifp->if_mtu. 1527 */ 1528 if (rt->rt_rmx.rmx_mtu) { 1529 dummyifp.if_mtu = rt->rt_rmx.rmx_mtu; 1530 destifp = &dummyifp; 1531 } 1532 } 1533 #endif /*IPSEC*/ 1534 ipstat.ips_cantfrag++; 1535 break; 1536 1537 case ENOBUFS: 1538 type = ICMP_SOURCEQUENCH; 1539 code = 0; 1540 break; 1541 } 1542 1543 icmp_error(mcopy, type, code, dest, destifp); 1544 } 1545 1546 int 1547 ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 1548 int *name; 1549 u_int namelen; 1550 void *oldp; 1551 size_t *oldlenp; 1552 void *newp; 1553 size_t newlen; 1554 { 1555 int error; 1556 1557 /* All sysctl names at this level are terminal. */ 1558 if (namelen != 1) 1559 return (ENOTDIR); 1560 1561 switch (name[0]) { 1562 case IPCTL_FORWARDING: 1563 return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding)); 1564 case IPCTL_SENDREDIRECTS: 1565 return (sysctl_int(oldp, oldlenp, newp, newlen, 1566 &ipsendredirects)); 1567 case IPCTL_DEFTTL: 1568 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl)); 1569 #ifdef notyet 1570 case IPCTL_DEFMTU: 1571 return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu)); 1572 #endif 1573 case IPCTL_SOURCEROUTE: 1574 /* 1575 * Don't allow this to change in a secure environment. 1576 */ 1577 if (newp && securelevel > 0) 1578 return (EPERM); 1579 return (sysctl_int(oldp, oldlenp, newp, newlen, 1580 &ip_dosourceroute)); 1581 case IPCTL_DIRECTEDBCAST: 1582 return (sysctl_int(oldp, oldlenp, newp, newlen, 1583 &ip_directedbcast)); 1584 case IPCTL_MTUDISC: 1585 error = sysctl_int(oldp, oldlenp, newp, newlen, 1586 &ip_mtudisc); 1587 if (ip_mtudisc != 0 && ip_mtudisc_timeout_q == NULL) { 1588 ip_mtudisc_timeout_q = 1589 rt_timer_queue_create(ip_mtudisc_timeout); 1590 } else if (ip_mtudisc == 0 && ip_mtudisc_timeout_q != NULL) { 1591 rt_timer_queue_destroy(ip_mtudisc_timeout_q, TRUE); 1592 Free(ip_mtudisc_timeout_q); 1593 ip_mtudisc_timeout_q = NULL; 1594 } 1595 return error; 1596 case IPCTL_MTUDISCTIMEOUT: 1597 error = sysctl_int(oldp, oldlenp, newp, newlen, 1598 &ip_mtudisc_timeout); 1599 if (ip_mtudisc_timeout_q != NULL) 1600 rt_timer_queue_change(ip_mtudisc_timeout_q, 1601 ip_mtudisc_timeout); 1602 return (error); 1603 case IPCTL_IPPORT_FIRSTAUTO: 1604 return (sysctl_int(oldp, oldlenp, newp, newlen, 1605 &ipport_firstauto)); 1606 case IPCTL_IPPORT_LASTAUTO: 1607 return (sysctl_int(oldp, oldlenp, newp, newlen, 1608 &ipport_lastauto)); 1609 case IPCTL_IPPORT_HIFIRSTAUTO: 1610 return (sysctl_int(oldp, oldlenp, newp, newlen, 1611 &ipport_hifirstauto)); 1612 case IPCTL_IPPORT_HILASTAUTO: 1613 return (sysctl_int(oldp, oldlenp, newp, newlen, 1614 &ipport_hilastauto)); 1615 case IPCTL_IPPORT_MAXQUEUE: 1616 return (sysctl_int(oldp, oldlenp, newp, newlen, 1617 &ip_maxqueue)); 1618 case IPCTL_ENCDEBUG: 1619 return (sysctl_int(oldp, oldlenp, newp, newlen, &encdebug)); 1620 case IPCTL_IPSEC_EMBRYONIC_SA_TIMEOUT: 1621 return (sysctl_int(oldp, oldlenp, newp, newlen, 1622 &ipsec_keep_invalid)); 1623 case IPCTL_IPSEC_REQUIRE_PFS: 1624 return (sysctl_int(oldp, oldlenp, newp, newlen, 1625 &ipsec_require_pfs)); 1626 case IPCTL_IPSEC_SOFT_ALLOCATIONS: 1627 return (sysctl_int(oldp, oldlenp, newp, newlen, 1628 &ipsec_soft_allocations)); 1629 case IPCTL_IPSEC_ALLOCATIONS: 1630 return (sysctl_int(oldp, oldlenp, newp, newlen, 1631 &ipsec_exp_allocations)); 1632 case IPCTL_IPSEC_SOFT_BYTES: 1633 return (sysctl_int(oldp, oldlenp, newp, newlen, 1634 &ipsec_soft_bytes)); 1635 case IPCTL_IPSEC_BYTES: 1636 return (sysctl_int(oldp, oldlenp, newp, newlen, 1637 &ipsec_exp_bytes)); 1638 case IPCTL_IPSEC_TIMEOUT: 1639 return (sysctl_int(oldp, oldlenp, newp, newlen, 1640 &ipsec_exp_timeout)); 1641 case IPCTL_IPSEC_SOFT_TIMEOUT: 1642 return (sysctl_int(oldp, oldlenp, newp, newlen, 1643 &ipsec_soft_timeout)); 1644 case IPCTL_IPSEC_SOFT_FIRSTUSE: 1645 return (sysctl_int(oldp, oldlenp, newp, newlen, 1646 &ipsec_soft_first_use)); 1647 case IPCTL_IPSEC_FIRSTUSE: 1648 return (sysctl_int(oldp, oldlenp, newp, newlen, 1649 &ipsec_exp_first_use)); 1650 case IPCTL_IPSEC_ENC_ALGORITHM: 1651 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1652 ipsec_def_enc, sizeof(ipsec_def_enc))); 1653 case IPCTL_IPSEC_AUTH_ALGORITHM: 1654 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1655 ipsec_def_auth, 1656 sizeof(ipsec_def_auth))); 1657 case IPCTL_IPSEC_EXPIRE_ACQUIRE: 1658 return (sysctl_int(oldp, oldlenp, newp, newlen, 1659 &ipsec_expire_acquire)); 1660 case IPCTL_IPSEC_IPCOMP_ALGORITHM: 1661 return (sysctl_tstring(oldp, oldlenp, newp, newlen, 1662 ipsec_def_comp, 1663 sizeof(ipsec_def_comp))); 1664 default: 1665 return (EOPNOTSUPP); 1666 } 1667 /* NOTREACHED */ 1668 } 1669