1 /* $OpenBSD: dispatch.c,v 1.31 2004/09/21 04:07:03 david Exp $ */ 2 3 /* 4 * Copyright 2004 Henning Brauer <henning@openbsd.org> 5 * Copyright (c) 1995, 1996, 1997, 1998, 1999 6 * The Internet Software Consortium. 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 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of The Internet Software Consortium nor the names 18 * of its contributors may be used to endorse or promote products derived 19 * from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND 22 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 23 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 25 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR 26 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 28 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 29 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 30 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 31 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 32 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * This software has been written for the Internet Software Consortium 36 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie 37 * Enterprises. To learn more about the Internet Software Consortium, 38 * see ``http://www.vix.com/isc''. To learn more about Vixie 39 * Enterprises, see ``http://www.vix.com''. 40 */ 41 42 #include "dhcpd.h" 43 44 #include <sys/ioctl.h> 45 46 #include <net/if_media.h> 47 #include <ifaddrs.h> 48 #include <poll.h> 49 50 struct protocol *protocols; 51 struct timeout *timeouts; 52 static struct timeout *free_timeouts; 53 static int interfaces_invalidated; 54 void (*bootp_packet_handler)(struct interface_info *, 55 struct dhcp_packet *, int, unsigned int, 56 struct iaddr, struct hardware *); 57 58 static int interface_status(struct interface_info *ifinfo); 59 60 /* 61 * Use getifaddrs() to get a list of all the attached interfaces. For 62 * each interface that's of type INET and not the loopback interface, 63 * register that interface with the network I/O software, figure out 64 * what subnet it's on, and add it to the list of interfaces. 65 */ 66 void 67 discover_interfaces(struct interface_info *iface) 68 { 69 struct ifaddrs *ifap, *ifa; 70 struct sockaddr_in foo; 71 struct ifreq *tif; 72 73 if (getifaddrs(&ifap) != 0) 74 error("getifaddrs failed"); 75 76 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 77 if ((ifa->ifa_flags & IFF_LOOPBACK) || 78 (ifa->ifa_flags & IFF_POINTOPOINT) || 79 (!(ifa->ifa_flags & IFF_UP))) 80 continue; 81 82 if (strcmp(iface->name, ifa->ifa_name)) 83 continue; 84 85 /* 86 * If we have the capability, extract link information 87 * and record it in a linked list. 88 */ 89 if (ifa->ifa_addr->sa_family == AF_LINK) { 90 struct sockaddr_dl *foo = 91 (struct sockaddr_dl *)ifa->ifa_addr; 92 93 iface->index = foo->sdl_index; 94 iface->hw_address.hlen = foo->sdl_alen; 95 iface->hw_address.htype = HTYPE_ETHER; /* XXX */ 96 memcpy(iface->hw_address.haddr, 97 LLADDR(foo), foo->sdl_alen); 98 } else if (ifa->ifa_addr->sa_family == AF_INET) { 99 struct iaddr addr; 100 101 memcpy(&foo, ifa->ifa_addr, sizeof(foo)); 102 if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK)) 103 continue; 104 if (!iface->ifp) { 105 int len = IFNAMSIZ + ifa->ifa_addr->sa_len; 106 if ((tif = malloc(len)) == NULL) 107 error("no space to remember ifp"); 108 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ); 109 memcpy(&tif->ifr_addr, ifa->ifa_addr, 110 ifa->ifa_addr->sa_len); 111 iface->ifp = tif; 112 iface->primary_address = foo.sin_addr; 113 } 114 addr.len = 4; 115 memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len); 116 } 117 } 118 119 if (!iface->ifp) 120 error("%s: not found", iface->name); 121 122 /* Register the interface... */ 123 if_register_receive(iface); 124 if_register_send(iface); 125 add_protocol(iface->name, iface->rfdesc, got_one, iface); 126 freeifaddrs(ifap); 127 } 128 129 void 130 reinitialize_interfaces(void) 131 { 132 interfaces_invalidated = 1; 133 } 134 135 /* 136 * Wait for packets to come in using poll(). When a packet comes in, 137 * call receive_packet to receive the packet and possibly strip hardware 138 * addressing information from it, and then call through the 139 * bootp_packet_handler hook to try to do something with it. 140 */ 141 void 142 dispatch(void) 143 { 144 int count, i, to_msec, nfds = 0; 145 struct protocol *l; 146 struct pollfd *fds; 147 time_t howlong; 148 149 for (l = protocols; l; l = l->next) 150 nfds++; 151 152 fds = malloc(nfds * sizeof(struct pollfd)); 153 if (fds == NULL) 154 error("Can't allocate poll structures."); 155 156 do { 157 /* 158 * Call any expired timeouts, and then if there's still 159 * a timeout registered, time out the select call then. 160 */ 161 another: 162 if (timeouts) { 163 struct timeout *t; 164 165 if (timeouts->when <= cur_time) { 166 t = timeouts; 167 timeouts = timeouts->next; 168 (*(t->func))(t->what); 169 t->next = free_timeouts; 170 free_timeouts = t; 171 goto another; 172 } 173 174 /* 175 * Figure timeout in milliseconds, and check for 176 * potential overflow, so we can cram into an 177 * int for poll, while not polling with a 178 * negative timeout and blocking indefinitely. 179 */ 180 howlong = timeouts->when - cur_time; 181 if (howlong > INT_MAX / 1000) 182 howlong = INT_MAX / 1000; 183 to_msec = howlong * 1000; 184 } else 185 to_msec = -1; 186 187 /* Set up the descriptors to be polled. */ 188 for (i = 0, l = protocols; l; l = l->next) { 189 struct interface_info *ip = l->local; 190 191 if (ip && (l->handler != got_one || !ip->dead)) { 192 fds[i].fd = l->fd; 193 fds[i].events = POLLIN; 194 fds[i].revents = 0; 195 i++; 196 } 197 } 198 199 if (i == 0) 200 error("No live interfaces to poll on - exiting."); 201 202 /* Wait for a packet or a timeout... XXX */ 203 count = poll(fds, nfds, to_msec); 204 205 /* Not likely to be transitory... */ 206 if (count == -1) { 207 if (errno == EAGAIN || errno == EINTR) { 208 time(&cur_time); 209 continue; 210 } else 211 error("poll: %m"); 212 } 213 214 /* Get the current time... */ 215 time(&cur_time); 216 217 i = 0; 218 for (l = protocols; l; l = l->next) { 219 struct interface_info *ip; 220 ip = l->local; 221 if ((fds[i].revents & (POLLIN | POLLHUP))) { 222 fds[i].revents = 0; 223 if (ip && (l->handler != got_one || 224 !ip->dead)) 225 (*(l->handler))(l); 226 if (interfaces_invalidated) 227 break; 228 } 229 i++; 230 } 231 interfaces_invalidated = 0; 232 } while (1); 233 } 234 235 236 void 237 got_one(struct protocol *l) 238 { 239 struct sockaddr_in from; 240 struct hardware hfrom; 241 struct iaddr ifrom; 242 ssize_t result; 243 union { 244 /* 245 * Packet input buffer. Must be as large as largest 246 * possible MTU. 247 */ 248 unsigned char packbuf[4095]; 249 struct dhcp_packet packet; 250 } u; 251 struct interface_info *ip = l->local; 252 253 if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from, 254 &hfrom)) == -1) { 255 warning("receive_packet failed on %s: %s", ip->name, 256 strerror(errno)); 257 ip->errors++; 258 if ((!interface_status(ip)) || 259 (ip->noifmedia && ip->errors > 20)) { 260 /* our interface has gone away. */ 261 warning("Interface %s no longer appears valid.", 262 ip->name); 263 ip->dead = 1; 264 interfaces_invalidated = 1; 265 close(l->fd); 266 remove_protocol(l); 267 free(ip); 268 } 269 return; 270 } 271 if (result == 0) 272 return; 273 274 if (bootp_packet_handler) { 275 ifrom.len = 4; 276 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len); 277 278 (*bootp_packet_handler)(ip, &u.packet, result, 279 from.sin_port, ifrom, &hfrom); 280 } 281 } 282 283 int 284 interface_status(struct interface_info *ifinfo) 285 { 286 char *ifname = ifinfo->name; 287 int ifsock = ifinfo->rfdesc; 288 struct ifreq ifr; 289 struct ifmediareq ifmr; 290 291 /* get interface flags */ 292 memset(&ifr, 0, sizeof(ifr)); 293 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 294 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) { 295 syslog(LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", ifname); 296 goto inactive; 297 } 298 299 /* 300 * if one of UP and RUNNING flags is dropped, 301 * the interface is not active. 302 */ 303 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) 304 goto inactive; 305 306 /* Next, check carrier on the interface, if possible */ 307 if (ifinfo->noifmedia) 308 goto active; 309 memset(&ifmr, 0, sizeof(ifmr)); 310 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 311 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) { 312 if (errno != EINVAL) { 313 syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m", 314 ifname); 315 316 ifinfo->noifmedia = 1; 317 goto active; 318 } 319 /* 320 * EINVAL (or ENOTTY) simply means that the interface 321 * does not support the SIOCGIFMEDIA ioctl. We regard it alive. 322 */ 323 ifinfo->noifmedia = 1; 324 goto active; 325 } 326 if (ifmr.ifm_status & IFM_AVALID) { 327 switch (ifmr.ifm_active & IFM_NMASK) { 328 case IFM_ETHER: 329 if (ifmr.ifm_status & IFM_ACTIVE) 330 goto active; 331 else 332 goto inactive; 333 break; 334 default: 335 goto inactive; 336 } 337 } 338 inactive: 339 return (0); 340 active: 341 return (1); 342 } 343 344 void 345 add_timeout(time_t when, void (*where)(void *), void *what) 346 { 347 struct timeout *t, *q; 348 349 /* See if this timeout supersedes an existing timeout. */ 350 t = NULL; 351 for (q = timeouts; q; q = q->next) { 352 if (q->func == where && q->what == what) { 353 if (t) 354 t->next = q->next; 355 else 356 timeouts = q->next; 357 break; 358 } 359 t = q; 360 } 361 362 /* If we didn't supersede a timeout, allocate a timeout 363 structure now. */ 364 if (!q) { 365 if (free_timeouts) { 366 q = free_timeouts; 367 free_timeouts = q->next; 368 q->func = where; 369 q->what = what; 370 } else { 371 q = malloc(sizeof(struct timeout)); 372 if (!q) 373 error("Can't allocate timeout structure!"); 374 q->func = where; 375 q->what = what; 376 } 377 } 378 379 q->when = when; 380 381 /* Now sort this timeout into the timeout list. */ 382 383 /* Beginning of list? */ 384 if (!timeouts || timeouts->when > q->when) { 385 q->next = timeouts; 386 timeouts = q; 387 return; 388 } 389 390 /* Middle of list? */ 391 for (t = timeouts; t->next; t = t->next) { 392 if (t->next->when > q->when) { 393 q->next = t->next; 394 t->next = q; 395 return; 396 } 397 } 398 399 /* End of list. */ 400 t->next = q; 401 q->next = NULL; 402 } 403 404 void 405 cancel_timeout(void (*where)(void *), void *what) 406 { 407 struct timeout *t, *q; 408 409 /* Look for this timeout on the list, and unlink it if we find it. */ 410 t = NULL; 411 for (q = timeouts; q; q = q->next) { 412 if (q->func == where && q->what == what) { 413 if (t) 414 t->next = q->next; 415 else 416 timeouts = q->next; 417 break; 418 } 419 t = q; 420 } 421 422 /* If we found the timeout, put it on the free list. */ 423 if (q) { 424 q->next = free_timeouts; 425 free_timeouts = q; 426 } 427 } 428 429 /* Add a protocol to the list of protocols... */ 430 void 431 add_protocol(char *name, int fd, void (*handler)(struct protocol *), 432 void *local) 433 { 434 struct protocol *p; 435 436 p = malloc(sizeof(*p)); 437 if (!p) 438 error("can't allocate protocol struct for %s", name); 439 440 p->fd = fd; 441 p->handler = handler; 442 p->local = local; 443 p->next = protocols; 444 protocols = p; 445 } 446 447 void 448 remove_protocol(struct protocol *proto) 449 { 450 struct protocol *p, *next, *prev; 451 452 prev = NULL; 453 for (p = protocols; p; p = next) { 454 next = p->next; 455 if (p == proto) { 456 if (prev) 457 prev->next = p->next; 458 else 459 protocols = p->next; 460 free(p); 461 } 462 } 463 } 464 465 int 466 interface_link_status(char *ifname) 467 { 468 struct ifmediareq ifmr; 469 int sock; 470 471 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 472 error("Can't create socket"); 473 474 memset(&ifmr, 0, sizeof(ifmr)); 475 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 476 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) { 477 /* EINVAL -> link state unknown. treat as active */ 478 if (errno != EINVAL) 479 syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m", 480 ifname); 481 close(sock); 482 return (1); 483 } 484 close(sock); 485 486 if (ifmr.ifm_status & IFM_AVALID) { 487 if ((ifmr.ifm_active & IFM_NMASK) == IFM_ETHER) { 488 if (ifmr.ifm_status & IFM_ACTIVE) 489 return (1); 490 else 491 return (0); 492 } 493 } 494 return (1); 495 } 496