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 <sys/cdefs.h> 43 __FBSDID("$FreeBSD$"); 44 45 #include "dhcpd.h" 46 47 #include <sys/ioctl.h> 48 49 #include <net/if_media.h> 50 #include <ifaddrs.h> 51 #include <poll.h> 52 53 struct protocol *protocols; 54 struct timeout *timeouts; 55 static struct timeout *free_timeouts; 56 static int interfaces_invalidated; 57 void (*bootp_packet_handler)(struct interface_info *, 58 struct dhcp_packet *, int, unsigned int, 59 struct iaddr, struct hardware *); 60 61 static int interface_status(struct interface_info *ifinfo); 62 63 /* 64 * Use getifaddrs() to get a list of all the attached interfaces. For 65 * each interface that's of type INET and not the loopback interface, 66 * register that interface with the network I/O software, figure out 67 * what subnet it's on, and add it to the list of interfaces. 68 */ 69 void 70 discover_interfaces(struct interface_info *iface) 71 { 72 struct ifaddrs *ifap, *ifa; 73 struct sockaddr_in foo; 74 struct ifreq *tif; 75 76 if (getifaddrs(&ifap) != 0) 77 error("getifaddrs failed"); 78 79 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 80 if ((ifa->ifa_flags & IFF_LOOPBACK) || 81 (ifa->ifa_flags & IFF_POINTOPOINT) || 82 (!(ifa->ifa_flags & IFF_UP))) 83 continue; 84 85 if (strcmp(iface->name, ifa->ifa_name)) 86 continue; 87 88 /* 89 * If we have the capability, extract link information 90 * and record it in a linked list. 91 */ 92 if (ifa->ifa_addr->sa_family == AF_LINK) { 93 struct sockaddr_dl *foo = 94 (struct sockaddr_dl *)ifa->ifa_addr; 95 96 iface->index = foo->sdl_index; 97 iface->hw_address.hlen = foo->sdl_alen; 98 iface->hw_address.htype = HTYPE_ETHER; /* XXX */ 99 memcpy(iface->hw_address.haddr, 100 LLADDR(foo), foo->sdl_alen); 101 } else if (ifa->ifa_addr->sa_family == AF_INET) { 102 struct iaddr addr; 103 104 memcpy(&foo, ifa->ifa_addr, sizeof(foo)); 105 if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK)) 106 continue; 107 if (!iface->ifp) { 108 int len = IFNAMSIZ + ifa->ifa_addr->sa_len; 109 if ((tif = malloc(len)) == NULL) 110 error("no space to remember ifp"); 111 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ); 112 memcpy(&tif->ifr_addr, ifa->ifa_addr, 113 ifa->ifa_addr->sa_len); 114 iface->ifp = tif; 115 iface->primary_address = foo.sin_addr; 116 } 117 addr.len = 4; 118 memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len); 119 } 120 } 121 122 if (!iface->ifp) 123 error("%s: not found", iface->name); 124 125 /* Register the interface... */ 126 if_register_receive(iface); 127 if_register_send(iface); 128 add_protocol(iface->name, iface->rfdesc, got_one, iface); 129 freeifaddrs(ifap); 130 } 131 132 void 133 reinitialize_interfaces(void) 134 { 135 interfaces_invalidated = 1; 136 } 137 138 /* 139 * Wait for packets to come in using poll(). When a packet comes in, 140 * call receive_packet to receive the packet and possibly strip hardware 141 * addressing information from it, and then call through the 142 * bootp_packet_handler hook to try to do something with it. 143 */ 144 void 145 dispatch(void) 146 { 147 int count, live_interfaces, i, to_msec, nfds = 0; 148 struct protocol *l; 149 struct pollfd *fds; 150 time_t howlong; 151 152 for (l = protocols; l; l = l->next) 153 nfds++; 154 155 fds = malloc(nfds * sizeof(struct pollfd)); 156 if (fds == NULL) 157 error("Can't allocate poll structures."); 158 159 do { 160 /* 161 * Call any expired timeouts, and then if there's still 162 * a timeout registered, time out the select call then. 163 */ 164 another: 165 if (timeouts) { 166 struct timeout *t; 167 168 if (timeouts->when <= cur_time) { 169 t = timeouts; 170 timeouts = timeouts->next; 171 (*(t->func))(t->what); 172 t->next = free_timeouts; 173 free_timeouts = t; 174 goto another; 175 } 176 177 /* 178 * Figure timeout in milliseconds, and check for 179 * potential overflow, so we can cram into an 180 * int for poll, while not polling with a 181 * negative timeout and blocking indefinitely. 182 */ 183 howlong = timeouts->when - cur_time; 184 if (howlong > INT_MAX / 1000) 185 howlong = INT_MAX / 1000; 186 to_msec = howlong * 1000; 187 } else 188 to_msec = -1; 189 190 /* Set up the descriptors to be polled. */ 191 live_interfaces = 0; 192 for (i = 0, l = protocols; l; l = l->next) { 193 struct interface_info *ip = l->local; 194 195 if (ip == NULL || ip->dead) 196 continue; 197 fds[i].fd = l->fd; 198 fds[i].events = POLLIN; 199 fds[i].revents = 0; 200 i++; 201 if (l->handler == got_one) 202 live_interfaces++; 203 } 204 if (live_interfaces == 0) 205 error("No live interfaces to poll on - exiting."); 206 207 /* Wait for a packet or a timeout... XXX */ 208 count = poll(fds, nfds, to_msec); 209 210 /* Not likely to be transitory... */ 211 if (count == -1) { 212 if (errno == EAGAIN || errno == EINTR) { 213 time(&cur_time); 214 continue; 215 } else 216 error("poll: %m"); 217 } 218 219 /* Get the current time... */ 220 time(&cur_time); 221 222 i = 0; 223 for (l = protocols; l; l = l->next) { 224 struct interface_info *ip; 225 ip = l->local; 226 if ((fds[i].revents & (POLLIN | POLLHUP))) { 227 fds[i].revents = 0; 228 if (ip && (l->handler != got_one || 229 !ip->dead)) 230 (*(l->handler))(l); 231 if (interfaces_invalidated) 232 break; 233 } 234 i++; 235 } 236 interfaces_invalidated = 0; 237 } while (1); 238 } 239 240 241 void 242 got_one(struct protocol *l) 243 { 244 struct sockaddr_in from; 245 struct hardware hfrom; 246 struct iaddr ifrom; 247 ssize_t result; 248 union { 249 /* 250 * Packet input buffer. Must be as large as largest 251 * possible MTU. 252 */ 253 unsigned char packbuf[4095]; 254 struct dhcp_packet packet; 255 } u; 256 struct interface_info *ip = l->local; 257 258 if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from, 259 &hfrom)) == -1) { 260 warning("receive_packet failed on %s: %s", ip->name, 261 strerror(errno)); 262 ip->errors++; 263 if ((!interface_status(ip)) || 264 (ip->noifmedia && ip->errors > 20)) { 265 /* our interface has gone away. */ 266 warning("Interface %s no longer appears valid.", 267 ip->name); 268 ip->dead = 1; 269 interfaces_invalidated = 1; 270 close(l->fd); 271 remove_protocol(l); 272 free(ip); 273 } 274 return; 275 } 276 if (result == 0) 277 return; 278 279 if (bootp_packet_handler) { 280 ifrom.len = 4; 281 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len); 282 283 (*bootp_packet_handler)(ip, &u.packet, result, 284 from.sin_port, ifrom, &hfrom); 285 } 286 } 287 288 int 289 interface_status(struct interface_info *ifinfo) 290 { 291 char *ifname = ifinfo->name; 292 int ifsock = ifinfo->rfdesc; 293 struct ifreq ifr; 294 struct ifmediareq ifmr; 295 296 /* get interface flags */ 297 memset(&ifr, 0, sizeof(ifr)); 298 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 299 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) { 300 syslog(LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", ifname); 301 goto inactive; 302 } 303 304 /* 305 * if one of UP and RUNNING flags is dropped, 306 * the interface is not active. 307 */ 308 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) 309 goto inactive; 310 311 /* Next, check carrier on the interface, if possible */ 312 if (ifinfo->noifmedia) 313 goto active; 314 memset(&ifmr, 0, sizeof(ifmr)); 315 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 316 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) { 317 if (errno != EINVAL) { 318 syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m", 319 ifname); 320 321 ifinfo->noifmedia = 1; 322 goto active; 323 } 324 /* 325 * EINVAL (or ENOTTY) simply means that the interface 326 * does not support the SIOCGIFMEDIA ioctl. We regard it alive. 327 */ 328 ifinfo->noifmedia = 1; 329 goto active; 330 } 331 if (ifmr.ifm_status & IFM_AVALID) { 332 switch (ifmr.ifm_active & IFM_NMASK) { 333 case IFM_ETHER: 334 case IFM_IEEE80211: 335 if (ifmr.ifm_status & IFM_ACTIVE) 336 goto active; 337 else 338 goto inactive; 339 break; 340 default: 341 goto inactive; 342 } 343 } 344 inactive: 345 return (0); 346 active: 347 return (1); 348 } 349 350 void 351 add_timeout(time_t when, void (*where)(void *), void *what) 352 { 353 struct timeout *t, *q; 354 355 /* See if this timeout supersedes an existing timeout. */ 356 t = NULL; 357 for (q = timeouts; q; q = q->next) { 358 if (q->func == where && q->what == what) { 359 if (t) 360 t->next = q->next; 361 else 362 timeouts = q->next; 363 break; 364 } 365 t = q; 366 } 367 368 /* If we didn't supersede a timeout, allocate a timeout 369 structure now. */ 370 if (!q) { 371 if (free_timeouts) { 372 q = free_timeouts; 373 free_timeouts = q->next; 374 q->func = where; 375 q->what = what; 376 } else { 377 q = malloc(sizeof(struct timeout)); 378 if (!q) 379 error("Can't allocate timeout structure!"); 380 q->func = where; 381 q->what = what; 382 } 383 } 384 385 q->when = when; 386 387 /* Now sort this timeout into the timeout list. */ 388 389 /* Beginning of list? */ 390 if (!timeouts || timeouts->when > q->when) { 391 q->next = timeouts; 392 timeouts = q; 393 return; 394 } 395 396 /* Middle of list? */ 397 for (t = timeouts; t->next; t = t->next) { 398 if (t->next->when > q->when) { 399 q->next = t->next; 400 t->next = q; 401 return; 402 } 403 } 404 405 /* End of list. */ 406 t->next = q; 407 q->next = NULL; 408 } 409 410 void 411 cancel_timeout(void (*where)(void *), void *what) 412 { 413 struct timeout *t, *q; 414 415 /* Look for this timeout on the list, and unlink it if we find it. */ 416 t = NULL; 417 for (q = timeouts; q; q = q->next) { 418 if (q->func == where && q->what == what) { 419 if (t) 420 t->next = q->next; 421 else 422 timeouts = q->next; 423 break; 424 } 425 t = q; 426 } 427 428 /* If we found the timeout, put it on the free list. */ 429 if (q) { 430 q->next = free_timeouts; 431 free_timeouts = q; 432 } 433 } 434 435 /* Add a protocol to the list of protocols... */ 436 void 437 add_protocol(char *name, int fd, void (*handler)(struct protocol *), 438 void *local) 439 { 440 struct protocol *p; 441 442 p = malloc(sizeof(*p)); 443 if (!p) 444 error("can't allocate protocol struct for %s", name); 445 446 p->fd = fd; 447 p->handler = handler; 448 p->local = local; 449 p->next = protocols; 450 protocols = p; 451 } 452 453 void 454 remove_protocol(struct protocol *proto) 455 { 456 struct protocol *p, *next, *prev; 457 458 prev = NULL; 459 for (p = protocols; p; p = next) { 460 next = p->next; 461 if (p == proto) { 462 if (prev) 463 prev->next = p->next; 464 else 465 protocols = p->next; 466 free(p); 467 } 468 } 469 } 470 471 int 472 interface_link_status(char *ifname) 473 { 474 struct ifmediareq ifmr; 475 int sock; 476 477 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 478 error("Can't create socket"); 479 480 memset(&ifmr, 0, sizeof(ifmr)); 481 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 482 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) { 483 /* EINVAL -> link state unknown. treat as active */ 484 if (errno != EINVAL) 485 syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m", 486 ifname); 487 close(sock); 488 return (1); 489 } 490 close(sock); 491 492 if (ifmr.ifm_status & IFM_AVALID) { 493 switch (ifmr.ifm_active & IFM_NMASK) { 494 case IFM_ETHER: 495 case IFM_IEEE80211: 496 if (ifmr.ifm_status & IFM_ACTIVE) 497 return (1); 498 else 499 return (0); 500 } 501 } 502 return (1); 503 } 504