1 /* $OpenBSD: dispatch.c,v 1.29 2011/11/12 15:39:52 krw 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 "dhcpd.h" 42 #include "sync.h" 43 #include <ifaddrs.h> 44 #include <sys/ioctl.h> 45 #include <poll.h> 46 #include <net/if_media.h> 47 48 extern int syncfd; 49 50 struct interface_info *interfaces; 51 struct protocol *protocols; 52 struct dhcpd_timeout *timeouts; 53 static struct dhcpd_timeout *free_timeouts; 54 static int interfaces_invalidated; 55 void (*bootp_packet_handler)(struct interface_info *, 56 struct dhcp_packet *, int, unsigned int, struct iaddr, struct hardware *); 57 58 static int interface_status(struct interface_info *ifinfo); 59 int get_rdomain(char *); 60 61 /* Use getifaddrs() to get a list of all the attached interfaces. 62 For each interface that's of type INET and not the loopback interface, 63 register that interface with the network I/O software, figure out what 64 subnet it's on, and add it to the list of interfaces. */ 65 66 void 67 discover_interfaces(int *rdomain) 68 { 69 struct interface_info *tmp; 70 struct interface_info *last, *next; 71 struct subnet *subnet; 72 struct shared_network *share; 73 struct sockaddr_in foo; 74 int ir = 0, ird; 75 struct ifreq *tif; 76 struct ifaddrs *ifap, *ifa; 77 78 if (getifaddrs(&ifap) != 0) 79 error("getifaddrs failed"); 80 81 /* 82 * If we already have a list of interfaces, the interfaces were 83 * requested. 84 */ 85 if (interfaces != NULL) 86 ir = 1; 87 else 88 /* must specify an interface when rdomains are used */ 89 *rdomain = 0; 90 91 /* Cycle through the list of interfaces looking for IP addresses. */ 92 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 93 /* 94 * See if this is the sort of interface we want to 95 * deal with. Skip loopback, point-to-point and down 96 * interfaces, except don't skip down interfaces if we're 97 * trying to get a list of configurable interfaces. 98 */ 99 if ((ifa->ifa_flags & IFF_LOOPBACK) || 100 (ifa->ifa_flags & IFF_POINTOPOINT) || 101 (!(ifa->ifa_flags & IFF_UP)) || 102 (!(ifa->ifa_flags & IFF_BROADCAST))) 103 continue; 104 105 /* See if we've seen an interface that matches this one. */ 106 for (tmp = interfaces; tmp; tmp = tmp->next) 107 if (!strcmp(tmp->name, ifa->ifa_name)) 108 break; 109 110 /* If we are looking for specific interfaces, ignore others. */ 111 if (tmp == NULL && ir) 112 continue; 113 114 ird = get_rdomain(ifa->ifa_name); 115 if (*rdomain == -1) 116 *rdomain = ird; 117 else if (*rdomain != ird && ir) 118 error("Interface %s is not in rdomain %d", 119 tmp->name, *rdomain); 120 else if (*rdomain != ird && !ir) 121 continue; 122 123 /* If there isn't already an interface by this name, 124 allocate one. */ 125 if (tmp == NULL) { 126 tmp = calloc(1, sizeof *tmp); 127 if (!tmp) 128 error("Insufficient memory to %s %s", 129 "record interface", ifa->ifa_name); 130 strlcpy(tmp->name, ifa->ifa_name, sizeof(tmp->name)); 131 tmp->next = interfaces; 132 tmp->noifmedia = tmp->dead = tmp->errors = 0; 133 interfaces = tmp; 134 } 135 136 /* If we have the capability, extract link information 137 and record it in a linked list. */ 138 if (ifa->ifa_addr->sa_family == AF_LINK) { 139 struct sockaddr_dl *foo = 140 ((struct sockaddr_dl *)(ifa->ifa_addr)); 141 tmp->index = foo->sdl_index; 142 tmp->hw_address.hlen = foo->sdl_alen; 143 tmp->hw_address.htype = HTYPE_ETHER; /* XXX */ 144 memcpy(tmp->hw_address.haddr, 145 LLADDR(foo), foo->sdl_alen); 146 } else if (ifa->ifa_addr->sa_family == AF_INET) { 147 struct iaddr addr; 148 149 /* Get a pointer to the address... */ 150 bcopy(ifa->ifa_addr, &foo, sizeof(foo)); 151 152 /* We don't want the loopback interface. */ 153 if (foo.sin_addr.s_addr == htonl (INADDR_LOOPBACK)) 154 continue; 155 156 /* If this is the first real IP address we've 157 found, keep a pointer to ifreq structure in 158 which we found it. */ 159 if (!tmp->ifp) { 160 int len = (IFNAMSIZ + ifa->ifa_addr->sa_len); 161 tif = (struct ifreq *)malloc(len); 162 if (!tif) 163 error("no space to remember ifp."); 164 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ); 165 memcpy(&tif->ifr_addr, ifa->ifa_addr, 166 ifa->ifa_addr->sa_len); 167 tmp->ifp = tif; 168 tmp->primary_address = foo.sin_addr; 169 } 170 171 /* Grab the address... */ 172 addr.len = 4; 173 memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len); 174 175 /* If there's a registered subnet for this address, 176 connect it together... */ 177 if ((subnet = find_subnet(addr))) { 178 /* If this interface has multiple aliases 179 on the same subnet, ignore all but the 180 first we encounter. */ 181 if (!subnet->interface) { 182 subnet->interface = tmp; 183 subnet->interface_address = addr; 184 } else if (subnet->interface != tmp) { 185 warning("Multiple %s %s: %s %s", 186 "interfaces match the", 187 "same subnet", 188 subnet->interface->name, 189 tmp->name); 190 } 191 share = subnet->shared_network; 192 if (tmp->shared_network && 193 tmp->shared_network != share) { 194 warning("Interface %s matches %s", 195 tmp->name, 196 "multiple shared networks"); 197 } else { 198 tmp->shared_network = share; 199 } 200 201 if (!share->interface) { 202 share->interface = tmp; 203 } else if (share->interface != tmp) { 204 warning("Multiple %s %s: %s %s", 205 "interfaces match the", 206 "same shared network", 207 share->interface->name, 208 tmp->name); 209 } 210 } 211 } 212 } 213 214 /* Discard interfaces we can't listen on. */ 215 last = NULL; 216 for (tmp = interfaces; tmp; tmp = next) { 217 next = tmp->next; 218 219 if (!tmp->ifp) { 220 warning("Can't listen on %s - it has no IP address.", 221 tmp->name); 222 /* Remove tmp from the list of interfaces. */ 223 if (!last) 224 interfaces = interfaces->next; 225 else 226 last->next = tmp->next; 227 continue; 228 } 229 230 memcpy(&foo, &tmp->ifp->ifr_addr, sizeof tmp->ifp->ifr_addr); 231 232 if (!tmp->shared_network) { 233 warning("Can't listen on %s - dhcpd.conf has no subnet " 234 "declaration for %s.", tmp->name, 235 inet_ntoa(foo.sin_addr)); 236 /* Remove tmp from the list of interfaces. */ 237 if (!last) 238 interfaces = interfaces->next; 239 else 240 last->next = tmp->next; 241 continue; 242 } 243 244 last = tmp; 245 246 /* Find subnets that don't have valid interface addresses. */ 247 for (subnet = (tmp->shared_network ? tmp->shared_network->subnets : 248 NULL); subnet; subnet = subnet->next_sibling) { 249 if (!subnet->interface_address.len) { 250 /* 251 * Set the interface address for this subnet 252 * to the first address we found. 253 */ 254 subnet->interface_address.len = 4; 255 memcpy(subnet->interface_address.iabuf, 256 &foo.sin_addr.s_addr, 4); 257 } 258 } 259 260 /* Register the interface... */ 261 if_register_receive(tmp); 262 if_register_send(tmp); 263 } 264 265 if (interfaces == NULL) 266 error("No interfaces to listen on."); 267 268 /* Now register all the remaining interfaces as protocols. */ 269 for (tmp = interfaces; tmp; tmp = tmp->next) 270 add_protocol(tmp->name, tmp->rfdesc, got_one, tmp); 271 272 freeifaddrs(ifap); 273 } 274 275 /* 276 * Wait for packets to come in using poll(). When a packet comes in, 277 * call receive_packet to receive the packet and possibly strip hardware 278 * addressing information from it, and then call through the 279 * bootp_packet_handler hook to try to do something with it. 280 */ 281 void 282 dispatch(void) 283 { 284 int nfds, i, to_msec; 285 struct protocol *l; 286 static struct pollfd *fds; 287 static int nfds_max; 288 time_t howlong; 289 290 for (nfds = 0, l = protocols; l; l = l->next) 291 nfds++; 292 if (syncfd != -1) 293 nfds++; 294 if (nfds > nfds_max) { 295 fds = realloc(fds, nfds * sizeof(struct pollfd)); 296 if (fds == NULL) 297 error("Can't allocate poll structures."); 298 nfds_max = nfds; 299 } 300 301 for (;;) { 302 /* 303 * Call any expired timeouts, and then if there's 304 * still a timeout registered, time out the poll 305 * call then. 306 */ 307 time(&cur_time); 308 another: 309 if (timeouts) { 310 if (timeouts->when <= cur_time) { 311 struct dhcpd_timeout *t = timeouts; 312 timeouts = timeouts->next; 313 (*(t->func))(t->what); 314 t->next = free_timeouts; 315 free_timeouts = t; 316 goto another; 317 } 318 319 /* 320 * Figure timeout in milliseconds, and check for 321 * potential overflow, so we can cram into an int 322 * for poll, while not polling with a negative 323 * timeout and blocking indefinitely. 324 */ 325 howlong = timeouts->when - cur_time; 326 if (howlong > INT_MAX / 1000) 327 howlong = INT_MAX / 1000; 328 to_msec = howlong * 1000; 329 } else 330 to_msec = -1; 331 332 /* Set up the descriptors to be polled. */ 333 for (i = 0, l = protocols; l; l = l->next) { 334 struct interface_info *ip = l->local; 335 336 if (ip && (l->handler != got_one || !ip->dead)) { 337 fds[i].fd = l->fd; 338 fds[i].events = POLLIN; 339 ++i; 340 } 341 } 342 343 if (i == 0) 344 error("No live interfaces to poll on - exiting."); 345 346 if (syncfd != -1) { 347 /* add syncer */ 348 fds[i].fd = syncfd; 349 fds[i].events = POLLIN; 350 } 351 352 /* Wait for a packet or a timeout... */ 353 switch (poll(fds, nfds, to_msec)) { 354 case -1: 355 if (errno != EAGAIN && errno != EINTR) 356 error("poll: %m"); 357 /* FALLTHROUGH */ 358 case 0: 359 continue; /* no packets */ 360 } 361 362 for (i = 0, l = protocols; l; l = l->next) { 363 struct interface_info *ip = l->local; 364 365 if ((fds[i].revents & (POLLIN | POLLHUP))) { 366 if (ip && (l->handler != got_one || 367 !ip->dead)) 368 (*(l->handler))(l); 369 if (interfaces_invalidated) 370 break; 371 } 372 ++i; 373 } 374 if ((syncfd != -1) && (fds[i].revents & (POLLIN | POLLHUP))) 375 sync_recv(); 376 interfaces_invalidated = 0; 377 } 378 } 379 380 381 void 382 got_one(struct protocol *l) 383 { 384 struct sockaddr_in from; 385 struct hardware hfrom; 386 struct iaddr ifrom; 387 ssize_t result; 388 union { 389 unsigned char packbuf[4095]; 390 struct dhcp_packet packet; 391 } u; 392 struct interface_info *ip = l->local; 393 394 bzero(&u, sizeof(u)); 395 396 if ((result = receive_packet(ip, u.packbuf, sizeof u, 397 &from, &hfrom)) == -1) { 398 warning("receive_packet failed on %s: %s", ip->name, 399 strerror(errno)); 400 ip->errors++; 401 if ((!interface_status(ip)) || 402 (ip->noifmedia && ip->errors > 20)) { 403 /* our interface has gone away. */ 404 warning("Interface %s no longer appears valid.", 405 ip->name); 406 ip->dead = 1; 407 interfaces_invalidated = 1; 408 close(l->fd); 409 remove_protocol(l); 410 free(ip); 411 } 412 return; 413 } 414 if (result == 0) 415 return; 416 417 if (bootp_packet_handler) { 418 ifrom.len = 4; 419 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len); 420 421 (*bootp_packet_handler)(ip, &u.packet, result, 422 from.sin_port, ifrom, &hfrom); 423 } 424 } 425 426 int 427 interface_status(struct interface_info *ifinfo) 428 { 429 char * ifname = ifinfo->name; 430 int ifsock = ifinfo->rfdesc; 431 struct ifreq ifr; 432 struct ifmediareq ifmr; 433 434 /* get interface flags */ 435 memset(&ifr, 0, sizeof(ifr)); 436 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 437 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) == -1) { 438 syslog(LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", ifname); 439 goto inactive; 440 } 441 /* 442 * if one of UP and RUNNING flags is dropped, 443 * the interface is not active. 444 */ 445 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) 446 goto inactive; 447 448 /* Next, check carrier on the interface, if possible */ 449 if (ifinfo->noifmedia) 450 goto active; 451 memset(&ifmr, 0, sizeof(ifmr)); 452 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 453 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) { 454 if (errno != EINVAL) { 455 syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m", 456 ifname); 457 ifinfo->noifmedia = 1; 458 goto active; 459 } 460 /* 461 * EINVAL (or ENOTTY) simply means that the interface 462 * does not support the SIOCGIFMEDIA ioctl. We regard it alive. 463 */ 464 ifinfo->noifmedia = 1; 465 goto active; 466 } 467 if (ifmr.ifm_status & IFM_AVALID) { 468 switch (ifmr.ifm_active & IFM_NMASK) { 469 case IFM_ETHER: 470 if (ifmr.ifm_status & IFM_ACTIVE) 471 goto active; 472 else 473 goto inactive; 474 break; 475 default: 476 goto inactive; 477 } 478 } 479 inactive: 480 return (0); 481 active: 482 return (1); 483 } 484 485 int 486 locate_network(struct packet *packet) 487 { 488 struct iaddr ia; 489 490 /* If this came through a gateway, find the corresponding subnet... */ 491 if (packet->raw->giaddr.s_addr) { 492 struct subnet *subnet; 493 494 ia.len = 4; 495 memcpy(ia.iabuf, &packet->raw->giaddr, 4); 496 subnet = find_subnet(ia); 497 if (subnet) 498 packet->shared_network = subnet->shared_network; 499 else 500 packet->shared_network = NULL; 501 } else { 502 packet->shared_network = packet->interface->shared_network; 503 } 504 if (packet->shared_network) 505 return 1; 506 return 0; 507 } 508 509 void 510 add_timeout(time_t when, void (*where)(void *), void *what) 511 { 512 struct dhcpd_timeout *t, *q; 513 514 /* See if this timeout supersedes an existing timeout. */ 515 t = NULL; 516 for (q = timeouts; q; q = q->next) { 517 if (q->func == where && q->what == what) { 518 if (t) 519 t->next = q->next; 520 else 521 timeouts = q->next; 522 break; 523 } 524 t = q; 525 } 526 527 /* If we didn't supersede a timeout, allocate a timeout 528 structure now. */ 529 if (!q) { 530 if (free_timeouts) { 531 q = free_timeouts; 532 free_timeouts = q->next; 533 q->func = where; 534 q->what = what; 535 } else { 536 q = (struct dhcpd_timeout *)malloc(sizeof (struct dhcpd_timeout)); 537 if (!q) 538 error("Can't allocate timeout structure!"); 539 q->func = where; 540 q->what = what; 541 } 542 } 543 544 q->when = when; 545 546 /* Now sort this timeout into the timeout list. */ 547 548 /* Beginning of list? */ 549 if (!timeouts || timeouts->when > q->when) { 550 q->next = timeouts; 551 timeouts = q; 552 return; 553 } 554 555 /* Middle of list? */ 556 for (t = timeouts; t->next; t = t->next) { 557 if (t->next->when > q->when) { 558 q->next = t->next; 559 t->next = q; 560 return; 561 } 562 } 563 564 /* End of list. */ 565 t->next = q; 566 q->next = NULL; 567 } 568 569 void 570 cancel_timeout(void (*where)(void *), void *what) 571 { 572 struct dhcpd_timeout *t, *q; 573 574 /* Look for this timeout on the list, and unlink it if we find it. */ 575 t = NULL; 576 for (q = timeouts; q; q = q->next) { 577 if (q->func == where && q->what == what) { 578 if (t) 579 t->next = q->next; 580 else 581 timeouts = q->next; 582 break; 583 } 584 t = q; 585 } 586 587 /* If we found the timeout, put it on the free list. */ 588 if (q) { 589 q->next = free_timeouts; 590 free_timeouts = q; 591 } 592 } 593 594 /* Add a protocol to the list of protocols... */ 595 void 596 add_protocol(char *name, int fd, void (*handler)(struct protocol *), 597 void *local) 598 { 599 struct protocol *p; 600 601 p = (struct protocol *)malloc(sizeof *p); 602 if (!p) 603 error("can't allocate protocol struct for %s", name); 604 p->fd = fd; 605 p->handler = handler; 606 p->local = local; 607 p->next = protocols; 608 protocols = p; 609 } 610 611 void 612 remove_protocol(struct protocol *proto) 613 { 614 struct protocol *p, *next, *prev = NULL; 615 616 for (p = protocols; p; p = next) { 617 next = p->next; 618 if (p == proto) { 619 if (prev) 620 prev->next = p->next; 621 else 622 protocols = p->next; 623 free(p); 624 } 625 } 626 } 627 628 int 629 get_rdomain(char *name) 630 { 631 int rv = 0, s; 632 struct ifreq ifr; 633 634 if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 635 error("get_rdomain socket: %m"); 636 637 bzero(&ifr, sizeof(ifr)); 638 strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name)); 639 if (ioctl(s, SIOCGIFRDOMAIN, (caddr_t)&ifr) != -1) 640 rv = ifr.ifr_rdomainid; 641 642 close(s); 643 return rv; 644 } 645