1 /* 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 34 * $FreeBSD$ 35 */ 36 37 #define _IP_VHL 38 39 #include "opt_bootp.h" 40 #include "opt_ipfw.h" 41 #include "opt_ipdn.h" 42 #include "opt_ipdivert.h" 43 #include "opt_ipfilter.h" 44 #include "opt_ipstealth.h" 45 46 #include <stddef.h> 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/mbuf.h> 51 #include <sys/malloc.h> 52 #include <sys/domain.h> 53 #include <sys/protosw.h> 54 #include <sys/socket.h> 55 #include <sys/time.h> 56 #include <sys/kernel.h> 57 #include <sys/syslog.h> 58 #include <sys/sysctl.h> 59 60 #include <net/if.h> 61 #include <net/if_var.h> 62 #include <net/if_dl.h> 63 #include <net/route.h> 64 #include <net/netisr.h> 65 66 #include <netinet/in.h> 67 #include <netinet/in_systm.h> 68 #include <netinet/in_var.h> 69 #include <netinet/ip.h> 70 #include <netinet/in_pcb.h> 71 #include <netinet/ip_var.h> 72 #include <netinet/ip_icmp.h> 73 #include <machine/in_cksum.h> 74 75 #include <sys/socketvar.h> 76 77 #include <netinet/ip_fw.h> 78 79 #ifdef DUMMYNET 80 #include <netinet/ip_dummynet.h> 81 #endif 82 83 int rsvp_on = 0; 84 static int ip_rsvp_on; 85 struct socket *ip_rsvpd; 86 87 int ipforwarding = 0; 88 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW, 89 &ipforwarding, 0, "Enable IP forwarding between interfaces"); 90 91 static int ipsendredirects = 1; /* XXX */ 92 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW, 93 &ipsendredirects, 0, "Enable sending IP redirects"); 94 95 int ip_defttl = IPDEFTTL; 96 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW, 97 &ip_defttl, 0, "Maximum TTL on IP packets"); 98 99 static int ip_dosourceroute = 0; 100 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 101 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 102 103 static int ip_acceptsourceroute = 0; 104 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 105 CTLFLAG_RW, &ip_acceptsourceroute, 0, 106 "Enable accepting source routed IP packets"); 107 #ifdef DIAGNOSTIC 108 static int ipprintfs = 0; 109 #endif 110 111 extern struct domain inetdomain; 112 extern struct protosw inetsw[]; 113 u_char ip_protox[IPPROTO_MAX]; 114 static int ipqmaxlen = IFQ_MAXLEN; 115 struct in_ifaddrhead in_ifaddrhead; /* first inet address */ 116 struct ifqueue ipintrq; 117 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW, 118 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue"); 119 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD, 120 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue"); 121 122 struct ipstat ipstat; 123 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RD, 124 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)"); 125 126 /* Packet reassembly stuff */ 127 #define IPREASS_NHASH_LOG2 6 128 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) 129 #define IPREASS_HMASK (IPREASS_NHASH - 1) 130 #define IPREASS_HASH(x,y) \ 131 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) 132 133 static struct ipq ipq[IPREASS_NHASH]; 134 static int nipq = 0; /* total # of reass queues */ 135 static int maxnipq; 136 137 #ifdef IPCTL_DEFMTU 138 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, 139 &ip_mtu, 0, "Default MTU"); 140 #endif 141 142 #ifdef IPSTEALTH 143 static int ipstealth = 0; 144 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, 145 &ipstealth, 0, ""); 146 #endif 147 148 149 /* Firewall hooks */ 150 ip_fw_chk_t *ip_fw_chk_ptr; 151 ip_fw_ctl_t *ip_fw_ctl_ptr; 152 153 #ifdef DUMMYNET 154 ip_dn_ctl_t *ip_dn_ctl_ptr; 155 #endif 156 157 #if defined(IPFILTER_LKM) || defined(IPFILTER) 158 int (*fr_checkp) __P((struct ip *, int, struct ifnet *, int, struct mbuf **)) = NULL; 159 #endif 160 161 162 /* 163 * We need to save the IP options in case a protocol wants to respond 164 * to an incoming packet over the same route if the packet got here 165 * using IP source routing. This allows connection establishment and 166 * maintenance when the remote end is on a network that is not known 167 * to us. 168 */ 169 static int ip_nhops = 0; 170 static struct ip_srcrt { 171 struct in_addr dst; /* final destination */ 172 char nop; /* one NOP to align */ 173 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ 174 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; 175 } ip_srcrt; 176 177 struct sockaddr_in *ip_fw_fwd_addr; 178 179 static void save_rte __P((u_char *, struct in_addr)); 180 static int ip_dooptions __P((struct mbuf *)); 181 static void ip_forward __P((struct mbuf *, int)); 182 static void ip_freef __P((struct ipq *)); 183 #ifdef IPDIVERT 184 static struct ip *ip_reass __P((struct mbuf *, 185 struct ipq *, struct ipq *, u_int32_t *, u_int16_t *)); 186 #else 187 static struct ip *ip_reass __P((struct mbuf *, struct ipq *, struct ipq *)); 188 #endif 189 static struct in_ifaddr *ip_rtaddr __P((struct in_addr)); 190 static void ipintr __P((void)); 191 192 /* 193 * IP initialization: fill in IP protocol switch table. 194 * All protocols not implemented in kernel go to raw IP protocol handler. 195 */ 196 void 197 ip_init() 198 { 199 register struct protosw *pr; 200 register int i; 201 202 TAILQ_INIT(&in_ifaddrhead); 203 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); 204 if (pr == 0) 205 panic("ip_init"); 206 for (i = 0; i < IPPROTO_MAX; i++) 207 ip_protox[i] = pr - inetsw; 208 for (pr = inetdomain.dom_protosw; 209 pr < inetdomain.dom_protoswNPROTOSW; pr++) 210 if (pr->pr_domain->dom_family == PF_INET && 211 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) 212 ip_protox[pr->pr_protocol] = pr - inetsw; 213 214 for (i = 0; i < IPREASS_NHASH; i++) 215 ipq[i].next = ipq[i].prev = &ipq[i]; 216 217 maxnipq = nmbclusters/4; 218 219 ip_id = time_second & 0xffff; 220 ipintrq.ifq_maxlen = ipqmaxlen; 221 } 222 223 static struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 224 static struct route ipforward_rt; 225 226 /* 227 * Ip input routine. Checksum and byte swap header. If fragmented 228 * try to reassemble. Process options. Pass to next level. 229 */ 230 void 231 ip_input(struct mbuf *m) 232 { 233 struct ip *ip; 234 struct ipq *fp; 235 struct in_ifaddr *ia; 236 int i, hlen, mff; 237 u_short sum; 238 u_int16_t divert_cookie; /* firewall cookie */ 239 #ifdef IPDIVERT 240 u_int32_t divert_info = 0; /* packet divert/tee info */ 241 #endif 242 struct ip_fw_chain *rule = NULL; 243 244 #ifdef IPDIVERT 245 /* Get and reset firewall cookie */ 246 divert_cookie = ip_divert_cookie; 247 ip_divert_cookie = 0; 248 #else 249 divert_cookie = 0; 250 #endif 251 252 #if defined(IPFIREWALL) && defined(DUMMYNET) 253 /* 254 * dummynet packet are prepended a vestigial mbuf with 255 * m_type = MT_DUMMYNET and m_data pointing to the matching 256 * rule. 257 */ 258 if (m->m_type == MT_DUMMYNET) { 259 rule = (struct ip_fw_chain *)(m->m_data) ; 260 m = m->m_next ; 261 ip = mtod(m, struct ip *); 262 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 263 goto iphack ; 264 } else 265 rule = NULL ; 266 #endif 267 268 #ifdef DIAGNOSTIC 269 if (m == NULL || (m->m_flags & M_PKTHDR) == 0) 270 panic("ip_input no HDR"); 271 #endif 272 ipstat.ips_total++; 273 274 if (m->m_pkthdr.len < sizeof(struct ip)) 275 goto tooshort; 276 277 if (m->m_len < sizeof (struct ip) && 278 (m = m_pullup(m, sizeof (struct ip))) == 0) { 279 ipstat.ips_toosmall++; 280 return; 281 } 282 ip = mtod(m, struct ip *); 283 284 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) { 285 ipstat.ips_badvers++; 286 goto bad; 287 } 288 289 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 290 if (hlen < sizeof(struct ip)) { /* minimum header length */ 291 ipstat.ips_badhlen++; 292 goto bad; 293 } 294 if (hlen > m->m_len) { 295 if ((m = m_pullup(m, hlen)) == 0) { 296 ipstat.ips_badhlen++; 297 return; 298 } 299 ip = mtod(m, struct ip *); 300 } 301 if (hlen == sizeof(struct ip)) { 302 sum = in_cksum_hdr(ip); 303 } else { 304 sum = in_cksum(m, hlen); 305 } 306 if (sum) { 307 ipstat.ips_badsum++; 308 goto bad; 309 } 310 311 /* 312 * Convert fields to host representation. 313 */ 314 NTOHS(ip->ip_len); 315 if (ip->ip_len < hlen) { 316 ipstat.ips_badlen++; 317 goto bad; 318 } 319 NTOHS(ip->ip_id); 320 NTOHS(ip->ip_off); 321 322 /* 323 * Check that the amount of data in the buffers 324 * is as at least much as the IP header would have us expect. 325 * Trim mbufs if longer than we expect. 326 * Drop packet if shorter than we expect. 327 */ 328 if (m->m_pkthdr.len < ip->ip_len) { 329 tooshort: 330 ipstat.ips_tooshort++; 331 goto bad; 332 } 333 if (m->m_pkthdr.len > ip->ip_len) { 334 if (m->m_len == m->m_pkthdr.len) { 335 m->m_len = ip->ip_len; 336 m->m_pkthdr.len = ip->ip_len; 337 } else 338 m_adj(m, ip->ip_len - m->m_pkthdr.len); 339 } 340 /* 341 * IpHack's section. 342 * Right now when no processing on packet has done 343 * and it is still fresh out of network we do our black 344 * deals with it. 345 * - Firewall: deny/allow/divert 346 * - Xlate: translate packet's addr/port (NAT). 347 * - Pipe: pass pkt through dummynet. 348 * - Wrap: fake packet's addr/port <unimpl.> 349 * - Encapsulate: put it in another IP and send out. <unimp.> 350 */ 351 352 #if defined(IPFIREWALL) && defined(DUMMYNET) 353 iphack: 354 #endif 355 #if defined(IPFILTER) || defined(IPFILTER_LKM) 356 /* 357 * Check if we want to allow this packet to be processed. 358 * Consider it to be bad if not. 359 */ 360 if (fr_checkp) { 361 struct mbuf *m1 = m; 362 363 if ((*fr_checkp)(ip, hlen, m->m_pkthdr.rcvif, 0, &m1) || !m1) 364 return; 365 ip = mtod(m = m1, struct ip *); 366 } 367 #endif 368 if (ip_fw_chk_ptr) { 369 #ifdef IPFIREWALL_FORWARD 370 /* 371 * If we've been forwarded from the output side, then 372 * skip the firewall a second time 373 */ 374 if (ip_fw_fwd_addr) 375 goto ours; 376 #endif /* IPFIREWALL_FORWARD */ 377 /* 378 * See the comment in ip_output for the return values 379 * produced by the firewall. 380 */ 381 i = (*ip_fw_chk_ptr)(&ip, 382 hlen, NULL, &divert_cookie, &m, &rule, &ip_fw_fwd_addr); 383 if (m == NULL) /* Packet discarded by firewall */ 384 return; 385 if (i == 0 && ip_fw_fwd_addr == NULL) /* common case */ 386 goto pass; 387 #ifdef DUMMYNET 388 if ((i & IP_FW_PORT_DYNT_FLAG) != 0) { 389 /* Send packet to the appropriate pipe */ 390 dummynet_io(i&0xffff,DN_TO_IP_IN,m,NULL,NULL,0, rule); 391 return; 392 } 393 #endif 394 #ifdef IPDIVERT 395 if (i != 0 && (i & IP_FW_PORT_DYNT_FLAG) == 0) { 396 /* Divert or tee packet */ 397 divert_info = i; 398 goto ours; 399 } 400 #endif 401 #ifdef IPFIREWALL_FORWARD 402 if (i == 0 && ip_fw_fwd_addr != NULL) 403 goto pass; 404 #endif 405 /* 406 * if we get here, the packet must be dropped 407 */ 408 m_freem(m); 409 return; 410 } 411 pass: 412 413 /* 414 * Process options and, if not destined for us, 415 * ship it on. ip_dooptions returns 1 when an 416 * error was detected (causing an icmp message 417 * to be sent and the original packet to be freed). 418 */ 419 ip_nhops = 0; /* for source routed packets */ 420 if (hlen > sizeof (struct ip) && ip_dooptions(m)) { 421 #ifdef IPFIREWALL_FORWARD 422 ip_fw_fwd_addr = NULL; 423 #endif 424 return; 425 } 426 427 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no 428 * matter if it is destined to another node, or whether it is 429 * a multicast one, RSVP wants it! and prevents it from being forwarded 430 * anywhere else. Also checks if the rsvp daemon is running before 431 * grabbing the packet. 432 */ 433 if (rsvp_on && ip->ip_p==IPPROTO_RSVP) 434 goto ours; 435 436 /* 437 * Check our list of addresses, to see if the packet is for us. 438 * If we don't have any addresses, assume any unicast packet 439 * we receive might be for us (and let the upper layers deal 440 * with it). 441 */ 442 if (TAILQ_EMPTY(&in_ifaddrhead) && 443 (m->m_flags & (M_MCAST|M_BCAST)) == 0) 444 goto ours; 445 446 for (ia = TAILQ_FIRST(&in_ifaddrhead); ia; 447 ia = TAILQ_NEXT(ia, ia_link)) { 448 #define satosin(sa) ((struct sockaddr_in *)(sa)) 449 450 #ifdef BOOTP_COMPAT 451 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) 452 goto ours; 453 #endif 454 #ifdef IPFIREWALL_FORWARD 455 /* 456 * If the addr to forward to is one of ours, we pretend to 457 * be the destination for this packet. 458 */ 459 if (ip_fw_fwd_addr == NULL) { 460 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 461 goto ours; 462 } else if (IA_SIN(ia)->sin_addr.s_addr == 463 ip_fw_fwd_addr->sin_addr.s_addr) 464 goto ours; 465 #else 466 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 467 goto ours; 468 #endif 469 if (ia->ia_ifp && ia->ia_ifp->if_flags & IFF_BROADCAST) { 470 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 471 ip->ip_dst.s_addr) 472 goto ours; 473 if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr) 474 goto ours; 475 } 476 } 477 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 478 struct in_multi *inm; 479 if (ip_mrouter) { 480 /* 481 * If we are acting as a multicast router, all 482 * incoming multicast packets are passed to the 483 * kernel-level multicast forwarding function. 484 * The packet is returned (relatively) intact; if 485 * ip_mforward() returns a non-zero value, the packet 486 * must be discarded, else it may be accepted below. 487 * 488 * (The IP ident field is put in the same byte order 489 * as expected when ip_mforward() is called from 490 * ip_output().) 491 */ 492 ip->ip_id = htons(ip->ip_id); 493 if (ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) { 494 ipstat.ips_cantforward++; 495 m_freem(m); 496 return; 497 } 498 ip->ip_id = ntohs(ip->ip_id); 499 500 /* 501 * The process-level routing demon needs to receive 502 * all multicast IGMP packets, whether or not this 503 * host belongs to their destination groups. 504 */ 505 if (ip->ip_p == IPPROTO_IGMP) 506 goto ours; 507 ipstat.ips_forward++; 508 } 509 /* 510 * See if we belong to the destination multicast group on the 511 * arrival interface. 512 */ 513 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); 514 if (inm == NULL) { 515 ipstat.ips_notmember++; 516 m_freem(m); 517 return; 518 } 519 goto ours; 520 } 521 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST) 522 goto ours; 523 if (ip->ip_dst.s_addr == INADDR_ANY) 524 goto ours; 525 526 /* 527 * Not for us; forward if possible and desirable. 528 */ 529 if (ipforwarding == 0) { 530 ipstat.ips_cantforward++; 531 m_freem(m); 532 } else 533 ip_forward(m, 0); 534 #ifdef IPFIREWALL_FORWARD 535 ip_fw_fwd_addr = NULL; 536 #endif 537 return; 538 539 ours: 540 541 /* 542 * If offset or IP_MF are set, must reassemble. 543 * Otherwise, nothing need be done. 544 * (We could look in the reassembly queue to see 545 * if the packet was previously fragmented, 546 * but it's not worth the time; just let them time out.) 547 */ 548 if (ip->ip_off & (IP_MF | IP_OFFMASK | IP_RF)) { 549 if (m->m_flags & M_EXT) { /* XXX */ 550 if ((m = m_pullup(m, hlen)) == 0) { 551 ipstat.ips_toosmall++; 552 #ifdef IPFIREWALL_FORWARD 553 ip_fw_fwd_addr = NULL; 554 #endif 555 return; 556 } 557 ip = mtod(m, struct ip *); 558 } 559 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); 560 /* 561 * Look for queue of fragments 562 * of this datagram. 563 */ 564 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) 565 if (ip->ip_id == fp->ipq_id && 566 ip->ip_src.s_addr == fp->ipq_src.s_addr && 567 ip->ip_dst.s_addr == fp->ipq_dst.s_addr && 568 ip->ip_p == fp->ipq_p) 569 goto found; 570 571 fp = 0; 572 573 /* check if there's a place for the new queue */ 574 if (nipq > maxnipq) { 575 /* 576 * drop something from the tail of the current queue 577 * before proceeding further 578 */ 579 if (ipq[sum].prev == &ipq[sum]) { /* gak */ 580 for (i = 0; i < IPREASS_NHASH; i++) { 581 if (ipq[i].prev != &ipq[i]) { 582 ip_freef(ipq[i].prev); 583 break; 584 } 585 } 586 } else 587 ip_freef(ipq[sum].prev); 588 } 589 found: 590 /* 591 * Adjust ip_len to not reflect header, 592 * set ip_mff if more fragments are expected, 593 * convert offset of this to bytes. 594 */ 595 ip->ip_len -= hlen; 596 mff = (ip->ip_off & IP_MF) != 0; 597 if (mff) { 598 /* 599 * Make sure that fragments have a data length 600 * that's a non-zero multiple of 8 bytes. 601 */ 602 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { 603 ipstat.ips_toosmall++; /* XXX */ 604 goto bad; 605 } 606 m->m_flags |= M_FRAG; 607 } 608 ip->ip_off <<= 3; 609 610 /* 611 * If datagram marked as having more fragments 612 * or if this is not the first fragment, 613 * attempt reassembly; if it succeeds, proceed. 614 */ 615 if (mff || ip->ip_off) { 616 ipstat.ips_fragments++; 617 m->m_pkthdr.header = ip; 618 #ifdef IPDIVERT 619 ip = ip_reass(m, 620 fp, &ipq[sum], &divert_info, &divert_cookie); 621 #else 622 ip = ip_reass(m, fp, &ipq[sum]); 623 #endif 624 if (ip == 0) { 625 #ifdef IPFIREWALL_FORWARD 626 ip_fw_fwd_addr = NULL; 627 #endif 628 return; 629 } 630 /* Get the length of the reassembled packets header */ 631 hlen = IP_VHL_HL(ip->ip_vhl) << 2; 632 ipstat.ips_reassembled++; 633 m = dtom(ip); 634 #ifdef IPDIVERT 635 /* Restore original checksum before diverting packet */ 636 if (divert_info != 0) { 637 ip->ip_len += hlen; 638 HTONS(ip->ip_len); 639 HTONS(ip->ip_off); 640 HTONS(ip->ip_id); 641 ip->ip_sum = 0; 642 ip->ip_sum = in_cksum_hdr(ip); 643 NTOHS(ip->ip_id); 644 NTOHS(ip->ip_off); 645 NTOHS(ip->ip_len); 646 ip->ip_len -= hlen; 647 } 648 #endif 649 } else 650 if (fp) 651 ip_freef(fp); 652 } else 653 ip->ip_len -= hlen; 654 655 #ifdef IPDIVERT 656 /* 657 * Divert or tee packet to the divert protocol if required. 658 * 659 * If divert_info is zero then cookie should be too, so we shouldn't 660 * need to clear them here. Assume divert_packet() does so also. 661 */ 662 if (divert_info != 0) { 663 struct mbuf *clone = NULL; 664 665 /* Clone packet if we're doing a 'tee' */ 666 if ((divert_info & IP_FW_PORT_TEE_FLAG) != 0) 667 clone = m_dup(m, M_DONTWAIT); 668 669 /* Restore packet header fields to original values */ 670 ip->ip_len += hlen; 671 HTONS(ip->ip_len); 672 HTONS(ip->ip_off); 673 HTONS(ip->ip_id); 674 675 /* Deliver packet to divert input routine */ 676 ip_divert_cookie = divert_cookie; 677 divert_packet(m, 1, divert_info & 0xffff); 678 ipstat.ips_delivered++; 679 680 /* If 'tee', continue with original packet */ 681 if (clone == NULL) 682 return; 683 m = clone; 684 ip = mtod(m, struct ip *); 685 } 686 #endif 687 688 /* 689 * Switch out to protocol's input routine. 690 */ 691 ipstat.ips_delivered++; 692 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); 693 #ifdef IPFIREWALL_FORWARD 694 ip_fw_fwd_addr = NULL; /* tcp needed it */ 695 #endif 696 return; 697 bad: 698 #ifdef IPFIREWALL_FORWARD 699 ip_fw_fwd_addr = NULL; 700 #endif 701 m_freem(m); 702 } 703 704 /* 705 * IP software interrupt routine - to go away sometime soon 706 */ 707 static void 708 ipintr(void) 709 { 710 int s; 711 struct mbuf *m; 712 713 while(1) { 714 s = splimp(); 715 IF_DEQUEUE(&ipintrq, m); 716 splx(s); 717 if (m == 0) 718 return; 719 ip_input(m); 720 } 721 } 722 723 NETISR_SET(NETISR_IP, ipintr); 724 725 /* 726 * Take incoming datagram fragment and try to reassemble it into 727 * whole datagram. If a chain for reassembly of this datagram already 728 * exists, then it is given as fp; otherwise have to make a chain. 729 * 730 * When IPDIVERT enabled, keep additional state with each packet that 731 * tells us if we need to divert or tee the packet we're building. 732 */ 733 734 static struct ip * 735 #ifdef IPDIVERT 736 ip_reass(m, fp, where, divinfo, divcookie) 737 #else 738 ip_reass(m, fp, where) 739 #endif 740 register struct mbuf *m; 741 register struct ipq *fp; 742 struct ipq *where; 743 #ifdef IPDIVERT 744 u_int32_t *divinfo; 745 u_int16_t *divcookie; 746 #endif 747 { 748 struct ip *ip = mtod(m, struct ip *); 749 register struct mbuf *p = 0, *q, *nq; 750 struct mbuf *t; 751 int hlen = IP_VHL_HL(ip->ip_vhl) << 2; 752 int i, next; 753 754 /* 755 * Presence of header sizes in mbufs 756 * would confuse code below. 757 */ 758 m->m_data += hlen; 759 m->m_len -= hlen; 760 761 /* 762 * If first fragment to arrive, create a reassembly queue. 763 */ 764 if (fp == 0) { 765 if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) 766 goto dropfrag; 767 fp = mtod(t, struct ipq *); 768 insque(fp, where); 769 nipq++; 770 fp->ipq_ttl = IPFRAGTTL; 771 fp->ipq_p = ip->ip_p; 772 fp->ipq_id = ip->ip_id; 773 fp->ipq_src = ip->ip_src; 774 fp->ipq_dst = ip->ip_dst; 775 fp->ipq_frags = m; 776 m->m_nextpkt = NULL; 777 #ifdef IPDIVERT 778 fp->ipq_div_info = 0; 779 fp->ipq_div_cookie = 0; 780 #endif 781 goto inserted; 782 } 783 784 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) 785 786 /* 787 * Find a segment which begins after this one does. 788 */ 789 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) 790 if (GETIP(q)->ip_off > 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, otherwise 797 * stick new segment in the proper place. 798 */ 799 if (p) { 800 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off; 801 if (i > 0) { 802 if (i >= ip->ip_len) 803 goto dropfrag; 804 m_adj(dtom(ip), i); 805 ip->ip_off += i; 806 ip->ip_len -= i; 807 } 808 m->m_nextpkt = p->m_nextpkt; 809 p->m_nextpkt = m; 810 } else { 811 m->m_nextpkt = fp->ipq_frags; 812 fp->ipq_frags = m; 813 } 814 815 /* 816 * While we overlap succeeding segments trim them or, 817 * if they are completely covered, dequeue them. 818 */ 819 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off; 820 q = nq) { 821 i = (ip->ip_off + ip->ip_len) - 822 GETIP(q)->ip_off; 823 if (i < GETIP(q)->ip_len) { 824 GETIP(q)->ip_len -= i; 825 GETIP(q)->ip_off += i; 826 m_adj(q, i); 827 break; 828 } 829 nq = q->m_nextpkt; 830 m->m_nextpkt = nq; 831 m_freem(q); 832 } 833 834 inserted: 835 836 #ifdef IPDIVERT 837 /* 838 * Transfer firewall instructions to the fragment structure. 839 * Any fragment diverting causes the whole packet to divert. 840 */ 841 fp->ipq_div_info = *divinfo; 842 fp->ipq_div_cookie = *divcookie; 843 *divinfo = 0; 844 *divcookie = 0; 845 #endif 846 847 /* 848 * Check for complete reassembly. 849 */ 850 next = 0; 851 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { 852 if (GETIP(q)->ip_off != next) 853 return (0); 854 next += GETIP(q)->ip_len; 855 } 856 /* Make sure the last packet didn't have the IP_MF flag */ 857 if (p->m_flags & M_FRAG) 858 return (0); 859 860 /* 861 * Reassembly is complete. Make sure the packet is a sane size. 862 */ 863 q = fp->ipq_frags; 864 ip = GETIP(q); 865 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) { 866 ipstat.ips_toolong++; 867 ip_freef(fp); 868 return (0); 869 } 870 871 /* 872 * Concatenate fragments. 873 */ 874 m = q; 875 t = m->m_next; 876 m->m_next = 0; 877 m_cat(m, t); 878 nq = q->m_nextpkt; 879 q->m_nextpkt = 0; 880 for (q = nq; q != NULL; q = nq) { 881 nq = q->m_nextpkt; 882 q->m_nextpkt = NULL; 883 m_cat(m, q); 884 } 885 886 #ifdef IPDIVERT 887 /* 888 * Extract firewall instructions from the fragment structure. 889 */ 890 *divinfo = fp->ipq_div_info; 891 *divcookie = fp->ipq_div_cookie; 892 #endif 893 894 /* 895 * Create header for new ip packet by 896 * modifying header of first packet; 897 * dequeue and discard fragment reassembly header. 898 * Make header visible. 899 */ 900 ip->ip_len = next; 901 ip->ip_src = fp->ipq_src; 902 ip->ip_dst = fp->ipq_dst; 903 remque(fp); 904 nipq--; 905 (void) m_free(dtom(fp)); 906 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2); 907 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2); 908 /* some debugging cruft by sklower, below, will go away soon */ 909 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ 910 register int plen = 0; 911 for (t = m; m; m = m->m_next) 912 plen += m->m_len; 913 t->m_pkthdr.len = plen; 914 } 915 return (ip); 916 917 dropfrag: 918 #ifdef IPDIVERT 919 *divinfo = 0; 920 *divcookie = 0; 921 #endif 922 ipstat.ips_fragdropped++; 923 m_freem(m); 924 return (0); 925 926 #undef GETIP 927 } 928 929 /* 930 * Free a fragment reassembly header and all 931 * associated datagrams. 932 */ 933 static void 934 ip_freef(fp) 935 struct ipq *fp; 936 { 937 register struct mbuf *q; 938 939 while (fp->ipq_frags) { 940 q = fp->ipq_frags; 941 fp->ipq_frags = q->m_nextpkt; 942 m_freem(q); 943 } 944 remque(fp); 945 (void) m_free(dtom(fp)); 946 nipq--; 947 } 948 949 /* 950 * IP timer processing; 951 * if a timer expires on a reassembly 952 * queue, discard it. 953 */ 954 void 955 ip_slowtimo() 956 { 957 register struct ipq *fp; 958 int s = splnet(); 959 int i; 960 961 for (i = 0; i < IPREASS_NHASH; i++) { 962 fp = ipq[i].next; 963 if (fp == 0) 964 continue; 965 while (fp != &ipq[i]) { 966 --fp->ipq_ttl; 967 fp = fp->next; 968 if (fp->prev->ipq_ttl == 0) { 969 ipstat.ips_fragtimeout++; 970 ip_freef(fp->prev); 971 } 972 } 973 } 974 ipflow_slowtimo(); 975 splx(s); 976 } 977 978 /* 979 * Drain off all datagram fragments. 980 */ 981 void 982 ip_drain() 983 { 984 int i; 985 986 for (i = 0; i < IPREASS_NHASH; i++) { 987 while (ipq[i].next != &ipq[i]) { 988 ipstat.ips_fragdropped++; 989 ip_freef(ipq[i].next); 990 } 991 } 992 in_rtqdrain(); 993 } 994 995 /* 996 * Do option processing on a datagram, 997 * possibly discarding it if bad options are encountered, 998 * or forwarding it if source-routed. 999 * Returns 1 if packet has been forwarded/freed, 1000 * 0 if the packet should be processed further. 1001 */ 1002 static int 1003 ip_dooptions(m) 1004 struct mbuf *m; 1005 { 1006 register struct ip *ip = mtod(m, struct ip *); 1007 register u_char *cp; 1008 register struct ip_timestamp *ipt; 1009 register struct in_ifaddr *ia; 1010 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 1011 struct in_addr *sin, dst; 1012 n_time ntime; 1013 1014 dst = ip->ip_dst; 1015 cp = (u_char *)(ip + 1); 1016 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1017 for (; cnt > 0; cnt -= optlen, cp += optlen) { 1018 opt = cp[IPOPT_OPTVAL]; 1019 if (opt == IPOPT_EOL) 1020 break; 1021 if (opt == IPOPT_NOP) 1022 optlen = 1; 1023 else { 1024 optlen = cp[IPOPT_OLEN]; 1025 if (optlen <= 0 || optlen > cnt) { 1026 code = &cp[IPOPT_OLEN] - (u_char *)ip; 1027 goto bad; 1028 } 1029 } 1030 switch (opt) { 1031 1032 default: 1033 break; 1034 1035 /* 1036 * Source routing with record. 1037 * Find interface with current destination address. 1038 * If none on this machine then drop if strictly routed, 1039 * or do nothing if loosely routed. 1040 * Record interface address and bring up next address 1041 * component. If strictly routed make sure next 1042 * address is on directly accessible net. 1043 */ 1044 case IPOPT_LSRR: 1045 case IPOPT_SSRR: 1046 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1047 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1048 goto bad; 1049 } 1050 ipaddr.sin_addr = ip->ip_dst; 1051 ia = (struct in_ifaddr *) 1052 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 1053 if (ia == 0) { 1054 if (opt == IPOPT_SSRR) { 1055 type = ICMP_UNREACH; 1056 code = ICMP_UNREACH_SRCFAIL; 1057 goto bad; 1058 } 1059 if (!ip_dosourceroute) 1060 goto nosourcerouting; 1061 /* 1062 * Loose routing, and not at next destination 1063 * yet; nothing to do except forward. 1064 */ 1065 break; 1066 } 1067 off--; /* 0 origin */ 1068 if (off > optlen - sizeof(struct in_addr)) { 1069 /* 1070 * End of source route. Should be for us. 1071 */ 1072 if (!ip_acceptsourceroute) 1073 goto nosourcerouting; 1074 save_rte(cp, ip->ip_src); 1075 break; 1076 } 1077 1078 if (!ip_dosourceroute) { 1079 if (ipforwarding) { 1080 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 1081 /* 1082 * Acting as a router, so generate ICMP 1083 */ 1084 nosourcerouting: 1085 strcpy(buf, inet_ntoa(ip->ip_dst)); 1086 log(LOG_WARNING, 1087 "attempted source route from %s to %s\n", 1088 inet_ntoa(ip->ip_src), buf); 1089 type = ICMP_UNREACH; 1090 code = ICMP_UNREACH_SRCFAIL; 1091 goto bad; 1092 } else { 1093 /* 1094 * Not acting as a router, so silently drop. 1095 */ 1096 ipstat.ips_cantforward++; 1097 m_freem(m); 1098 return (1); 1099 } 1100 } 1101 1102 /* 1103 * locate outgoing interface 1104 */ 1105 (void)memcpy(&ipaddr.sin_addr, cp + off, 1106 sizeof(ipaddr.sin_addr)); 1107 1108 if (opt == IPOPT_SSRR) { 1109 #define INA struct in_ifaddr * 1110 #define SA struct sockaddr * 1111 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) 1112 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 1113 } else 1114 ia = ip_rtaddr(ipaddr.sin_addr); 1115 if (ia == 0) { 1116 type = ICMP_UNREACH; 1117 code = ICMP_UNREACH_SRCFAIL; 1118 goto bad; 1119 } 1120 ip->ip_dst = ipaddr.sin_addr; 1121 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1122 sizeof(struct in_addr)); 1123 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1124 /* 1125 * Let ip_intr's mcast routing check handle mcast pkts 1126 */ 1127 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 1128 break; 1129 1130 case IPOPT_RR: 1131 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 1132 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 1133 goto bad; 1134 } 1135 /* 1136 * If no space remains, ignore. 1137 */ 1138 off--; /* 0 origin */ 1139 if (off > optlen - sizeof(struct in_addr)) 1140 break; 1141 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 1142 sizeof(ipaddr.sin_addr)); 1143 /* 1144 * locate outgoing interface; if we're the destination, 1145 * use the incoming interface (should be same). 1146 */ 1147 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && 1148 (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { 1149 type = ICMP_UNREACH; 1150 code = ICMP_UNREACH_HOST; 1151 goto bad; 1152 } 1153 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 1154 sizeof(struct in_addr)); 1155 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 1156 break; 1157 1158 case IPOPT_TS: 1159 code = cp - (u_char *)ip; 1160 ipt = (struct ip_timestamp *)cp; 1161 if (ipt->ipt_len < 5) 1162 goto bad; 1163 if (ipt->ipt_ptr > ipt->ipt_len - sizeof(int32_t)) { 1164 if (++ipt->ipt_oflw == 0) 1165 goto bad; 1166 break; 1167 } 1168 sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); 1169 switch (ipt->ipt_flg) { 1170 1171 case IPOPT_TS_TSONLY: 1172 break; 1173 1174 case IPOPT_TS_TSANDADDR: 1175 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1176 sizeof(struct in_addr) > ipt->ipt_len) 1177 goto bad; 1178 ipaddr.sin_addr = dst; 1179 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 1180 m->m_pkthdr.rcvif); 1181 if (ia == 0) 1182 continue; 1183 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 1184 sizeof(struct in_addr)); 1185 ipt->ipt_ptr += sizeof(struct in_addr); 1186 break; 1187 1188 case IPOPT_TS_PRESPEC: 1189 if (ipt->ipt_ptr - 1 + sizeof(n_time) + 1190 sizeof(struct in_addr) > ipt->ipt_len) 1191 goto bad; 1192 (void)memcpy(&ipaddr.sin_addr, sin, 1193 sizeof(struct in_addr)); 1194 if (ifa_ifwithaddr((SA)&ipaddr) == 0) 1195 continue; 1196 ipt->ipt_ptr += sizeof(struct in_addr); 1197 break; 1198 1199 default: 1200 goto bad; 1201 } 1202 ntime = iptime(); 1203 (void)memcpy(cp + ipt->ipt_ptr - 1, &ntime, 1204 sizeof(n_time)); 1205 ipt->ipt_ptr += sizeof(n_time); 1206 } 1207 } 1208 if (forward && ipforwarding) { 1209 ip_forward(m, 1); 1210 return (1); 1211 } 1212 return (0); 1213 bad: 1214 ip->ip_len -= IP_VHL_HL(ip->ip_vhl) << 2; /* XXX icmp_error adds in hdr length */ 1215 icmp_error(m, type, code, 0, 0); 1216 ipstat.ips_badoptions++; 1217 return (1); 1218 } 1219 1220 /* 1221 * Given address of next destination (final or next hop), 1222 * return internet address info of interface to be used to get there. 1223 */ 1224 static struct in_ifaddr * 1225 ip_rtaddr(dst) 1226 struct in_addr dst; 1227 { 1228 register struct sockaddr_in *sin; 1229 1230 sin = (struct sockaddr_in *) &ipforward_rt.ro_dst; 1231 1232 if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { 1233 if (ipforward_rt.ro_rt) { 1234 RTFREE(ipforward_rt.ro_rt); 1235 ipforward_rt.ro_rt = 0; 1236 } 1237 sin->sin_family = AF_INET; 1238 sin->sin_len = sizeof(*sin); 1239 sin->sin_addr = dst; 1240 1241 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1242 } 1243 if (ipforward_rt.ro_rt == 0) 1244 return ((struct in_ifaddr *)0); 1245 return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa); 1246 } 1247 1248 /* 1249 * Save incoming source route for use in replies, 1250 * to be picked up later by ip_srcroute if the receiver is interested. 1251 */ 1252 void 1253 save_rte(option, dst) 1254 u_char *option; 1255 struct in_addr dst; 1256 { 1257 unsigned olen; 1258 1259 olen = option[IPOPT_OLEN]; 1260 #ifdef DIAGNOSTIC 1261 if (ipprintfs) 1262 printf("save_rte: olen %d\n", olen); 1263 #endif 1264 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) 1265 return; 1266 bcopy(option, ip_srcrt.srcopt, olen); 1267 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 1268 ip_srcrt.dst = dst; 1269 } 1270 1271 /* 1272 * Retrieve incoming source route for use in replies, 1273 * in the same form used by setsockopt. 1274 * The first hop is placed before the options, will be removed later. 1275 */ 1276 struct mbuf * 1277 ip_srcroute() 1278 { 1279 register struct in_addr *p, *q; 1280 register struct mbuf *m; 1281 1282 if (ip_nhops == 0) 1283 return ((struct mbuf *)0); 1284 m = m_get(M_DONTWAIT, MT_HEADER); 1285 if (m == 0) 1286 return ((struct mbuf *)0); 1287 1288 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) 1289 1290 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 1291 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + 1292 OPTSIZ; 1293 #ifdef DIAGNOSTIC 1294 if (ipprintfs) 1295 printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); 1296 #endif 1297 1298 /* 1299 * First save first hop for return route 1300 */ 1301 p = &ip_srcrt.route[ip_nhops - 1]; 1302 *(mtod(m, struct in_addr *)) = *p--; 1303 #ifdef DIAGNOSTIC 1304 if (ipprintfs) 1305 printf(" hops %lx", (u_long)ntohl(mtod(m, struct in_addr *)->s_addr)); 1306 #endif 1307 1308 /* 1309 * Copy option fields and padding (nop) to mbuf. 1310 */ 1311 ip_srcrt.nop = IPOPT_NOP; 1312 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 1313 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 1314 &ip_srcrt.nop, OPTSIZ); 1315 q = (struct in_addr *)(mtod(m, caddr_t) + 1316 sizeof(struct in_addr) + OPTSIZ); 1317 #undef OPTSIZ 1318 /* 1319 * Record return path as an IP source route, 1320 * reversing the path (pointers are now aligned). 1321 */ 1322 while (p >= ip_srcrt.route) { 1323 #ifdef DIAGNOSTIC 1324 if (ipprintfs) 1325 printf(" %lx", (u_long)ntohl(q->s_addr)); 1326 #endif 1327 *q++ = *p--; 1328 } 1329 /* 1330 * Last hop goes to final destination. 1331 */ 1332 *q = ip_srcrt.dst; 1333 #ifdef DIAGNOSTIC 1334 if (ipprintfs) 1335 printf(" %lx\n", (u_long)ntohl(q->s_addr)); 1336 #endif 1337 return (m); 1338 } 1339 1340 /* 1341 * Strip out IP options, at higher 1342 * level protocol in the kernel. 1343 * Second argument is buffer to which options 1344 * will be moved, and return value is their length. 1345 * XXX should be deleted; last arg currently ignored. 1346 */ 1347 void 1348 ip_stripoptions(m, mopt) 1349 register struct mbuf *m; 1350 struct mbuf *mopt; 1351 { 1352 register int i; 1353 struct ip *ip = mtod(m, struct ip *); 1354 register caddr_t opts; 1355 int olen; 1356 1357 olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip); 1358 opts = (caddr_t)(ip + 1); 1359 i = m->m_len - (sizeof (struct ip) + olen); 1360 bcopy(opts + olen, opts, (unsigned)i); 1361 m->m_len -= olen; 1362 if (m->m_flags & M_PKTHDR) 1363 m->m_pkthdr.len -= olen; 1364 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2); 1365 } 1366 1367 u_char inetctlerrmap[PRC_NCMDS] = { 1368 0, 0, 0, 0, 1369 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, 1370 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, 1371 EMSGSIZE, EHOSTUNREACH, 0, 0, 1372 0, 0, 0, 0, 1373 ENOPROTOOPT 1374 }; 1375 1376 /* 1377 * Forward a packet. If some error occurs return the sender 1378 * an icmp packet. Note we can't always generate a meaningful 1379 * icmp message because icmp doesn't have a large enough repertoire 1380 * of codes and types. 1381 * 1382 * If not forwarding, just drop the packet. This could be confusing 1383 * if ipforwarding was zero but some routing protocol was advancing 1384 * us as a gateway to somewhere. However, we must let the routing 1385 * protocol deal with that. 1386 * 1387 * The srcrt parameter indicates whether the packet is being forwarded 1388 * via a source route. 1389 */ 1390 static void 1391 ip_forward(m, srcrt) 1392 struct mbuf *m; 1393 int srcrt; 1394 { 1395 register struct ip *ip = mtod(m, struct ip *); 1396 register struct sockaddr_in *sin; 1397 register struct rtentry *rt; 1398 int error, type = 0, code = 0; 1399 struct mbuf *mcopy; 1400 n_long dest; 1401 struct ifnet *destifp; 1402 1403 dest = 0; 1404 #ifdef DIAGNOSTIC 1405 if (ipprintfs) 1406 printf("forward: src %lx dst %lx ttl %x\n", 1407 (u_long)ip->ip_src.s_addr, (u_long)ip->ip_dst.s_addr, 1408 ip->ip_ttl); 1409 #endif 1410 1411 1412 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) { 1413 ipstat.ips_cantforward++; 1414 m_freem(m); 1415 return; 1416 } 1417 HTONS(ip->ip_id); 1418 #ifdef IPSTEALTH 1419 if (!ipstealth) { 1420 #endif 1421 if (ip->ip_ttl <= IPTTLDEC) { 1422 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 1423 dest, 0); 1424 return; 1425 } 1426 ip->ip_ttl -= IPTTLDEC; 1427 #ifdef IPSTEALTH 1428 } 1429 #endif 1430 1431 sin = (struct sockaddr_in *)&ipforward_rt.ro_dst; 1432 if ((rt = ipforward_rt.ro_rt) == 0 || 1433 ip->ip_dst.s_addr != sin->sin_addr.s_addr) { 1434 if (ipforward_rt.ro_rt) { 1435 RTFREE(ipforward_rt.ro_rt); 1436 ipforward_rt.ro_rt = 0; 1437 } 1438 sin->sin_family = AF_INET; 1439 sin->sin_len = sizeof(*sin); 1440 sin->sin_addr = ip->ip_dst; 1441 1442 rtalloc_ign(&ipforward_rt, RTF_PRCLONING); 1443 if (ipforward_rt.ro_rt == 0) { 1444 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); 1445 return; 1446 } 1447 rt = ipforward_rt.ro_rt; 1448 } 1449 1450 /* 1451 * Save at most 64 bytes of the packet in case 1452 * we need to generate an ICMP message to the src. 1453 */ 1454 mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); 1455 1456 /* 1457 * If forwarding packet using same interface that it came in on, 1458 * perhaps should send a redirect to sender to shortcut a hop. 1459 * Only send redirect if source is sending directly to us, 1460 * and if packet was not source routed (or has any options). 1461 * Also, don't send redirect if forwarding using a default route 1462 * or a route modified by a redirect. 1463 */ 1464 #define satosin(sa) ((struct sockaddr_in *)(sa)) 1465 if (rt->rt_ifp == m->m_pkthdr.rcvif && 1466 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && 1467 satosin(rt_key(rt))->sin_addr.s_addr != 0 && 1468 ipsendredirects && !srcrt) { 1469 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa)) 1470 u_long src = ntohl(ip->ip_src.s_addr); 1471 1472 if (RTA(rt) && 1473 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) { 1474 if (rt->rt_flags & RTF_GATEWAY) 1475 dest = satosin(rt->rt_gateway)->sin_addr.s_addr; 1476 else 1477 dest = ip->ip_dst.s_addr; 1478 /* Router requirements says to only send host redirects */ 1479 type = ICMP_REDIRECT; 1480 code = ICMP_REDIRECT_HOST; 1481 #ifdef DIAGNOSTIC 1482 if (ipprintfs) 1483 printf("redirect (%d) to %lx\n", code, (u_long)dest); 1484 #endif 1485 } 1486 } 1487 1488 error = ip_output(m, (struct mbuf *)0, &ipforward_rt, 1489 IP_FORWARDING, 0); 1490 if (error) 1491 ipstat.ips_cantforward++; 1492 else { 1493 ipstat.ips_forward++; 1494 if (type) 1495 ipstat.ips_redirectsent++; 1496 else { 1497 if (mcopy) { 1498 ipflow_create(&ipforward_rt, mcopy); 1499 m_freem(mcopy); 1500 } 1501 return; 1502 } 1503 } 1504 if (mcopy == NULL) 1505 return; 1506 destifp = NULL; 1507 1508 switch (error) { 1509 1510 case 0: /* forwarded, but need redirect */ 1511 /* type, code set above */ 1512 break; 1513 1514 case ENETUNREACH: /* shouldn't happen, checked above */ 1515 case EHOSTUNREACH: 1516 case ENETDOWN: 1517 case EHOSTDOWN: 1518 default: 1519 type = ICMP_UNREACH; 1520 code = ICMP_UNREACH_HOST; 1521 break; 1522 1523 case EMSGSIZE: 1524 type = ICMP_UNREACH; 1525 code = ICMP_UNREACH_NEEDFRAG; 1526 if (ipforward_rt.ro_rt) 1527 destifp = ipforward_rt.ro_rt->rt_ifp; 1528 ipstat.ips_cantfrag++; 1529 break; 1530 1531 case ENOBUFS: 1532 type = ICMP_SOURCEQUENCH; 1533 code = 0; 1534 break; 1535 } 1536 icmp_error(mcopy, type, code, dest, destifp); 1537 } 1538 1539 void 1540 ip_savecontrol(inp, mp, ip, m) 1541 register struct inpcb *inp; 1542 register struct mbuf **mp; 1543 register struct ip *ip; 1544 register struct mbuf *m; 1545 { 1546 if (inp->inp_socket->so_options & SO_TIMESTAMP) { 1547 struct timeval tv; 1548 1549 microtime(&tv); 1550 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv), 1551 SCM_TIMESTAMP, SOL_SOCKET); 1552 if (*mp) 1553 mp = &(*mp)->m_next; 1554 } 1555 if (inp->inp_flags & INP_RECVDSTADDR) { 1556 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst, 1557 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP); 1558 if (*mp) 1559 mp = &(*mp)->m_next; 1560 } 1561 #ifdef notyet 1562 /* XXX 1563 * Moving these out of udp_input() made them even more broken 1564 * than they already were. 1565 */ 1566 /* options were tossed already */ 1567 if (inp->inp_flags & INP_RECVOPTS) { 1568 *mp = sbcreatecontrol((caddr_t) opts_deleted_above, 1569 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP); 1570 if (*mp) 1571 mp = &(*mp)->m_next; 1572 } 1573 /* ip_srcroute doesn't do what we want here, need to fix */ 1574 if (inp->inp_flags & INP_RECVRETOPTS) { 1575 *mp = sbcreatecontrol((caddr_t) ip_srcroute(), 1576 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP); 1577 if (*mp) 1578 mp = &(*mp)->m_next; 1579 } 1580 #endif 1581 if (inp->inp_flags & INP_RECVIF) { 1582 struct ifnet *ifp; 1583 struct sdlbuf { 1584 struct sockaddr_dl sdl; 1585 u_char pad[32]; 1586 } sdlbuf; 1587 struct sockaddr_dl *sdp; 1588 struct sockaddr_dl *sdl2 = &sdlbuf.sdl; 1589 1590 if (((ifp = m->m_pkthdr.rcvif)) 1591 && ( ifp->if_index && (ifp->if_index <= if_index))) { 1592 sdp = (struct sockaddr_dl *)(ifnet_addrs 1593 [ifp->if_index - 1]->ifa_addr); 1594 /* 1595 * Change our mind and don't try copy. 1596 */ 1597 if ((sdp->sdl_family != AF_LINK) 1598 || (sdp->sdl_len > sizeof(sdlbuf))) { 1599 goto makedummy; 1600 } 1601 bcopy(sdp, sdl2, sdp->sdl_len); 1602 } else { 1603 makedummy: 1604 sdl2->sdl_len 1605 = offsetof(struct sockaddr_dl, sdl_data[0]); 1606 sdl2->sdl_family = AF_LINK; 1607 sdl2->sdl_index = 0; 1608 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0; 1609 } 1610 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len, 1611 IP_RECVIF, IPPROTO_IP); 1612 if (*mp) 1613 mp = &(*mp)->m_next; 1614 } 1615 } 1616 1617 int 1618 ip_rsvp_init(struct socket *so) 1619 { 1620 if (so->so_type != SOCK_RAW || 1621 so->so_proto->pr_protocol != IPPROTO_RSVP) 1622 return EOPNOTSUPP; 1623 1624 if (ip_rsvpd != NULL) 1625 return EADDRINUSE; 1626 1627 ip_rsvpd = so; 1628 /* 1629 * This may seem silly, but we need to be sure we don't over-increment 1630 * the RSVP counter, in case something slips up. 1631 */ 1632 if (!ip_rsvp_on) { 1633 ip_rsvp_on = 1; 1634 rsvp_on++; 1635 } 1636 1637 return 0; 1638 } 1639 1640 int 1641 ip_rsvp_done(void) 1642 { 1643 ip_rsvpd = NULL; 1644 /* 1645 * This may seem silly, but we need to be sure we don't over-decrement 1646 * the RSVP counter, in case something slips up. 1647 */ 1648 if (ip_rsvp_on) { 1649 ip_rsvp_on = 0; 1650 rsvp_on--; 1651 } 1652 return 0; 1653 } 1654