1/* $OpenBSD: dispatch.c,v 1.45 2023/09/02 10:18:45 kn Exp $ */ 2 3/* 4 * Copyright (c) 1995, 1996, 1997, 1998, 1999 5 * The Internet Software Consortium. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 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 Internet Software Consortium nor the names 17 * of its contributors may be used to endorse or promote products derived 18 * from this software without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND 21 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 22 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 24 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR 25 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 27 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 28 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 29 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * This software has been written for the Internet Software Consortium 35 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie 36 * Enterprises. To learn more about the Internet Software Consortium, 37 * see ``http://www.vix.com/isc''. To learn more about Vixie 38 * Enterprises, see ``http://www.vix.com''. 39 */ 40 41#include <sys/types.h> 42#include <sys/ioctl.h> 43#include <sys/socket.h> 44 45#include <arpa/inet.h> 46 47#include <net/if.h> 48#include <net/if_dl.h> 49#include <net/if_media.h> 50 51#include <netinet/in.h> 52 53#include <errno.h> 54#include <ifaddrs.h> 55#include <limits.h> 56#include <poll.h> 57#include <stdio.h> 58#include <stdlib.h> 59#include <string.h> 60#include <syslog.h> 61#include <time.h> 62#include <unistd.h> 63 64#include "dhcp.h" 65#include "tree.h" 66#include "dhcpd.h" 67#include "log.h" 68#include "sync.h" 69 70extern int syncfd; 71 72struct interface_info *interfaces; 73struct protocol *protocols; 74struct dhcpd_timeout *timeouts; 75static struct dhcpd_timeout *free_timeouts; 76static int interfaces_invalidated; 77 78static int interface_status(struct interface_info *ifinfo); 79int get_rdomain(char *); 80 81/* Use getifaddrs() to get a list of all the attached interfaces. 82 For each interface that's of type INET and not the loopback interface, 83 register that interface with the network I/O software, figure out what 84 subnet it's on, and add it to the list of interfaces. */ 85 86void 87discover_interfaces(int *rdomain) 88{ 89 struct interface_info *tmp; 90 struct interface_info *last, *next; 91 struct subnet *subnet; 92 struct shared_network *share; 93 struct sockaddr_in foo; 94 int ir = 0, ird; 95 struct ifreq *tif; 96 struct ifaddrs *ifap, *ifa; 97 98 if (getifaddrs(&ifap) != 0) 99 fatalx("getifaddrs failed"); 100 101 /* 102 * If we already have a list of interfaces, the interfaces were 103 * requested. 104 */ 105 if (interfaces != NULL) 106 ir = 1; 107 else 108 /* must specify an interface when rdomains are used */ 109 *rdomain = 0; 110 111 /* Cycle through the list of interfaces looking for IP addresses. */ 112 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 113 /* 114 * See if this is the sort of interface we want to 115 * deal with. 116 */ 117 if ((ifa->ifa_flags & IFF_LOOPBACK) || 118 (ifa->ifa_flags & IFF_POINTOPOINT) || 119 (!(ifa->ifa_flags & IFF_BROADCAST))) 120 continue; 121 122 /* See if we've seen an interface that matches this one. */ 123 for (tmp = interfaces; tmp; tmp = tmp->next) 124 if (!strcmp(tmp->name, ifa->ifa_name)) 125 break; 126 127 /* If we are looking for specific interfaces, ignore others. */ 128 if (tmp == NULL && ir) 129 continue; 130 131 ird = get_rdomain(ifa->ifa_name); 132 if (*rdomain == -1) 133 *rdomain = ird; 134 else if (*rdomain != ird && ir) 135 fatalx("Interface %s is not in rdomain %d", 136 tmp->name, *rdomain); 137 else if (*rdomain != ird && !ir) 138 continue; 139 140 /* If there isn't already an interface by this name, 141 allocate one. */ 142 if (tmp == NULL) { 143 tmp = calloc(1, sizeof *tmp); 144 if (!tmp) 145 fatalx("Insufficient memory to %s %s", 146 "record interface", ifa->ifa_name); 147 strlcpy(tmp->name, ifa->ifa_name, sizeof(tmp->name)); 148 tmp->next = interfaces; 149 tmp->noifmedia = tmp->dead = tmp->errors = 0; 150 interfaces = tmp; 151 } 152 153 /* If we have the capability, extract link information 154 and record it in a linked list. */ 155 if (ifa->ifa_addr->sa_family == AF_LINK) { 156 struct sockaddr_dl *sdl = 157 ((struct sockaddr_dl *)(ifa->ifa_addr)); 158 tmp->index = sdl->sdl_index; 159 tmp->hw_address.hlen = sdl->sdl_alen; 160 tmp->hw_address.htype = HTYPE_ETHER; /* XXX */ 161 memcpy(tmp->hw_address.haddr, 162 LLADDR(sdl), sdl->sdl_alen); 163 } else if (ifa->ifa_addr->sa_family == AF_INET) { 164 struct iaddr addr; 165 166 /* Get a pointer to the address... */ 167 memcpy(&foo, ifa->ifa_addr, sizeof(foo)); 168 169 /* We don't want the loopback interface. */ 170 if (foo.sin_addr.s_addr == htonl (INADDR_LOOPBACK)) 171 continue; 172 173 /* If this is the first real IP address we've 174 found, keep a pointer to ifreq structure in 175 which we found it. */ 176 if (!tmp->ifp) { 177 int len = (IFNAMSIZ + ifa->ifa_addr->sa_len); 178 tif = malloc(len); 179 if (!tif) 180 fatalx("no space to remember ifp."); 181 strlcpy(tif->ifr_name, ifa->ifa_name, 182 IFNAMSIZ); 183 memcpy(&tif->ifr_addr, ifa->ifa_addr, 184 ifa->ifa_addr->sa_len); 185 tmp->ifp = tif; 186 tmp->primary_address = foo.sin_addr; 187 } 188 189 /* Grab the address... */ 190 addr.len = 4; 191 memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len); 192 193 /* If there's a registered subnet for this address, 194 connect it together... */ 195 if ((subnet = find_subnet(addr))) { 196 /* If this interface has multiple aliases 197 on the same subnet, ignore all but the 198 first we encounter. */ 199 if (!subnet->interface) { 200 subnet->interface = tmp; 201 subnet->interface_address = addr; 202 } else if (subnet->interface != tmp) { 203 log_warnx("Multiple %s %s: %s %s", 204 "interfaces match the", 205 "same subnet", 206 subnet->interface->name, 207 tmp->name); 208 } 209 share = subnet->shared_network; 210 if (tmp->shared_network && 211 tmp->shared_network != share) { 212 log_warnx("Interface %s matches %s", 213 tmp->name, 214 "multiple shared networks"); 215 } else { 216 tmp->shared_network = share; 217 } 218 219 if (!share->interface) { 220 share->interface = tmp; 221 } else if (share->interface != tmp) { 222 log_warnx("Multiple %s %s: %s %s", 223 "interfaces match the", 224 "same shared network", 225 share->interface->name, 226 tmp->name); 227 } 228 } 229 } 230 } 231 232 /* Discard interfaces we can't listen on. */ 233 last = NULL; 234 for (tmp = interfaces; tmp; tmp = next) { 235 next = tmp->next; 236 237 if (!tmp->ifp) { 238 log_warnx("Can't listen on %s - it has no IP address.", 239 tmp->name); 240 /* Remove tmp from the list of interfaces. */ 241 if (!last) 242 interfaces = interfaces->next; 243 else 244 last->next = tmp->next; 245 continue; 246 } 247 248 memcpy(&foo, &tmp->ifp->ifr_addr, sizeof tmp->ifp->ifr_addr); 249 250 if (!tmp->shared_network) { 251 log_warnx("Can't listen on %s - dhcpd.conf has no " 252 "subnet declaration for %s.", tmp->name, 253 inet_ntoa(foo.sin_addr)); 254 /* Remove tmp from the list of interfaces. */ 255 if (!last) 256 interfaces = interfaces->next; 257 else 258 last->next = tmp->next; 259 continue; 260 } 261 262 last = tmp; 263 264 /* Find subnets that don't have valid interface addresses. */ 265 for (subnet = (tmp->shared_network ? 266 tmp->shared_network->subnets : NULL); subnet; 267 subnet = subnet->next_sibling) { 268 if (!subnet->interface_address.len) { 269 /* 270 * Set the interface address for this subnet 271 * to the first address we found. 272 */ 273 subnet->interface_address.len = 4; 274 memcpy(subnet->interface_address.iabuf, 275 &foo.sin_addr.s_addr, 4); 276 } 277 } 278 279 /* Register the interface... */ 280 if_register_receive(tmp); 281 if_register_send(tmp); 282 log_info("Listening on %s (%s).", tmp->name, 283 inet_ntoa(foo.sin_addr)); 284 } 285 286 if (interfaces == NULL) 287 fatalx("No interfaces to listen on."); 288 289 /* Now register all the remaining interfaces as protocols. */ 290 for (tmp = interfaces; tmp; tmp = tmp->next) 291 add_protocol(tmp->name, tmp->rfdesc, got_one, tmp); 292 293 freeifaddrs(ifap); 294} 295 296/* 297 * Wait for packets to come in using poll(). When a packet comes in, 298 * call receive_packet to receive the packet and possibly strip hardware 299 * addressing information from it, and then process it in do_packet. 300 */ 301void 302dispatch(void) 303{ 304 int nfds, i, to_msec; 305 struct protocol *l; 306 static struct pollfd *fds; 307 static int nfds_max; 308 time_t howlong; 309 310 for (nfds = 0, l = protocols; l; l = l->next) 311 nfds++; 312 if (syncfd != -1) 313 nfds++; 314 if (nfds > nfds_max) { 315 fds = reallocarray(fds, nfds, sizeof(struct pollfd)); 316 if (fds == NULL) 317 fatalx("Can't allocate poll structures."); 318 nfds_max = nfds; 319 } 320 321 for (;;) { 322 /* 323 * Call any expired timeouts, and then if there's 324 * still a timeout registered, time out the poll 325 * call then. 326 */ 327 time(&cur_time); 328another: 329 if (timeouts) { 330 if (timeouts->when <= cur_time) { 331 struct dhcpd_timeout *t = timeouts; 332 timeouts = timeouts->next; 333 (*(t->func))(t->what); 334 t->next = free_timeouts; 335 free_timeouts = t; 336 goto another; 337 } 338 339 /* 340 * Figure timeout in milliseconds, and check for 341 * potential overflow, so we can cram into an int 342 * for poll, while not polling with a negative 343 * timeout and blocking indefinitely. 344 */ 345 howlong = timeouts->when - cur_time; 346 if (howlong > INT_MAX / 1000) 347 howlong = INT_MAX / 1000; 348 to_msec = howlong * 1000; 349 } else 350 to_msec = -1; 351 352 /* Set up the descriptors to be polled. */ 353 for (i = 0, l = protocols; l; l = l->next) { 354 struct interface_info *ip = l->local; 355 356 if (ip && (l->handler != got_one || !ip->dead)) { 357 fds[i].fd = l->fd; 358 fds[i].events = POLLIN; 359 ++i; 360 } 361 } 362 363 if (i == 0) 364 fatalx("No live interfaces to poll on - exiting."); 365 366 if (syncfd != -1) { 367 /* add syncer */ 368 fds[i].fd = syncfd; 369 fds[i].events = POLLIN; 370 } 371 372 /* Wait for a packet or a timeout... */ 373 switch (poll(fds, nfds, to_msec)) { 374 case -1: 375 if (errno != EAGAIN && errno != EINTR) 376 fatal("poll"); 377 /* FALLTHROUGH */ 378 case 0: 379 continue; /* no packets */ 380 } 381 time(&cur_time); 382 383 for (i = 0, l = protocols; l; l = l->next) { 384 struct interface_info *ip = l->local; 385 386 if ((fds[i].revents & (POLLIN | POLLHUP))) { 387 if (ip && (l->handler != got_one || 388 !ip->dead)) 389 (*(l->handler))(l); 390 if (interfaces_invalidated) 391 break; 392 } 393 ++i; 394 } 395 if ((syncfd != -1) && (fds[i].revents & (POLLIN | POLLHUP))) 396 sync_recv(); 397 interfaces_invalidated = 0; 398 } 399} 400 401 402void 403got_one(struct protocol *l) 404{ 405 struct sockaddr_in from; 406 struct hardware hfrom; 407 struct iaddr ifrom; 408 ssize_t result; 409 union { 410 unsigned char packbuf[4095]; 411 struct dhcp_packet packet; 412 } u; 413 struct interface_info *ip = l->local; 414 415 memset(&u, 0, sizeof(u)); 416 417 if ((result = receive_packet(ip, u.packbuf, sizeof u, 418 &from, &hfrom)) == -1) { 419 log_warn("receive_packet failed on %s", ip->name); 420 ip->errors++; 421 if ((!interface_status(ip)) || 422 (ip->noifmedia && ip->errors > 20)) { 423 /* our interface has gone away. */ 424 log_warnx("Interface %s no longer appears valid.", 425 ip->name); 426 ip->dead = 1; 427 interfaces_invalidated = 1; 428 close(l->fd); 429 remove_protocol(l); 430 free(ip); 431 } 432 return; 433 } 434 if (result == 0) 435 return; 436 437 ifrom.len = 4; 438 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len); 439 440 do_packet(ip, &u.packet, result, from.sin_port, ifrom, &hfrom); 441} 442 443int 444interface_status(struct interface_info *ifinfo) 445{ 446 char * ifname = ifinfo->name; 447 int ifsock = ifinfo->rfdesc; 448 struct ifreq ifr; 449 struct ifmediareq ifmr; 450 451 /* get interface flags */ 452 memset(&ifr, 0, sizeof(ifr)); 453 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 454 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) == -1) { 455 log_warn("ioctl(SIOCGIFFLAGS) on %s", ifname); 456 goto inactive; 457 } 458 /* 459 * if one of UP and RUNNING flags is dropped, 460 * the interface is not active. 461 */ 462 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) 463 goto inactive; 464 465 /* Next, check carrier on the interface, if possible */ 466 if (ifinfo->noifmedia) 467 goto active; 468 memset(&ifmr, 0, sizeof(ifmr)); 469 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 470 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) { 471 if (errno != EINVAL) { 472 log_debug("ioctl(SIOCGIFMEDIA) on %s", ifname); 473 ifinfo->noifmedia = 1; 474 goto active; 475 } 476 /* 477 * EINVAL (or ENOTTY) simply means that the interface 478 * does not support the SIOCGIFMEDIA ioctl. We regard it alive. 479 */ 480 ifinfo->noifmedia = 1; 481 goto active; 482 } 483 if (ifmr.ifm_status & IFM_AVALID) { 484 switch (ifmr.ifm_active & IFM_NMASK) { 485 case IFM_ETHER: 486 if (ifmr.ifm_status & IFM_ACTIVE) 487 goto active; 488 else 489 goto inactive; 490 break; 491 default: 492 goto inactive; 493 } 494 } 495 inactive: 496 return (0); 497 active: 498 return (1); 499} 500 501int 502locate_network(struct packet *packet) 503{ 504 struct iaddr ia; 505 506 /* If this came through a gateway, find the corresponding subnet... */ 507 if (packet->raw->giaddr.s_addr) { 508 struct subnet *subnet; 509 510 ia.len = 4; 511 memcpy(ia.iabuf, &packet->raw->giaddr, 4); 512 subnet = find_subnet(ia); 513 if (subnet) 514 packet->shared_network = subnet->shared_network; 515 else 516 packet->shared_network = NULL; 517 } else { 518 packet->shared_network = packet->interface->shared_network; 519 } 520 if (packet->shared_network) 521 return 1; 522 return 0; 523} 524 525void 526add_timeout(time_t when, void (*where)(void *), void *what) 527{ 528 struct dhcpd_timeout *t, *q; 529 530 /* See if this timeout supersedes an existing timeout. */ 531 t = NULL; 532 for (q = timeouts; q; q = q->next) { 533 if (q->func == where && q->what == what) { 534 if (t) 535 t->next = q->next; 536 else 537 timeouts = q->next; 538 break; 539 } 540 t = q; 541 } 542 543 /* If we didn't supersede a timeout, allocate a timeout 544 structure now. */ 545 if (!q) { 546 if (free_timeouts) { 547 q = free_timeouts; 548 free_timeouts = q->next; 549 q->func = where; 550 q->what = what; 551 } else { 552 q = malloc(sizeof (struct dhcpd_timeout)); 553 if (!q) 554 fatalx("Can't allocate timeout structure!"); 555 q->func = where; 556 q->what = what; 557 } 558 } 559 560 q->when = when; 561 562 /* Now sort this timeout into the timeout list. */ 563 564 /* Beginning of list? */ 565 if (!timeouts || timeouts->when > q->when) { 566 q->next = timeouts; 567 timeouts = q; 568 return; 569 } 570 571 /* Middle of list? */ 572 for (t = timeouts; t->next; t = t->next) { 573 if (t->next->when > q->when) { 574 q->next = t->next; 575 t->next = q; 576 return; 577 } 578 } 579 580 /* End of list. */ 581 t->next = q; 582 q->next = NULL; 583} 584 585void 586cancel_timeout(void (*where)(void *), void *what) 587{ 588 struct dhcpd_timeout *t, *q; 589 590 /* Look for this timeout on the list, and unlink it if we find it. */ 591 t = NULL; 592 for (q = timeouts; q; q = q->next) { 593 if (q->func == where && q->what == what) { 594 if (t) 595 t->next = q->next; 596 else 597 timeouts = q->next; 598 break; 599 } 600 t = q; 601 } 602 603 /* If we found the timeout, put it on the free list. */ 604 if (q) { 605 q->next = free_timeouts; 606 free_timeouts = q; 607 } 608} 609 610/* Add a protocol to the list of protocols... */ 611void 612add_protocol(char *name, int fd, void (*handler)(struct protocol *), 613 void *local) 614{ 615 struct protocol *p; 616 617 p = malloc(sizeof *p); 618 if (!p) 619 fatalx("can't allocate protocol struct for %s", name); 620 p->fd = fd; 621 p->handler = handler; 622 p->local = local; 623 p->next = protocols; 624 protocols = p; 625} 626 627void 628remove_protocol(struct protocol *proto) 629{ 630 struct protocol *p, *next, *prev = NULL; 631 632 for (p = protocols; p; p = next) { 633 next = p->next; 634 if (p == proto) { 635 if (prev) 636 prev->next = p->next; 637 else 638 protocols = p->next; 639 free(p); 640 } 641 } 642} 643 644int 645get_rdomain(char *name) 646{ 647 int rv = 0, s; 648 struct ifreq ifr; 649 650 if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 651 fatal("get_rdomain socket"); 652 653 memset(&ifr, 0, sizeof(ifr)); 654 strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name)); 655 if (ioctl(s, SIOCGIFRDOMAIN, (caddr_t)&ifr) != -1) 656 rv = ifr.ifr_rdomainid; 657 658 close(s); 659 return rv; 660} 661