1 /* $OpenBSD: dispatch.c,v 1.1 2017/03/17 14:45:16 rzalamena 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/types.h> 43 #include <sys/ioctl.h> 44 #include <sys/socket.h> 45 46 #include <net/if.h> 47 #include <net/if_dl.h> 48 #include <net/if_media.h> 49 #include <net/if_types.h> 50 51 #include <netinet/in.h> 52 #include <netinet/if_ether.h> 53 54 #include <errno.h> 55 #include <ifaddrs.h> 56 #include <limits.h> 57 #include <poll.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 "dhcpd.h" 66 #include "log.h" 67 68 /* 69 * Macros implementation used to generate link-local addresses. This 70 * code was copied from: sys/netinet6/in6_ifattach.c. 71 */ 72 #define EUI64_UBIT 0x02 73 #define EUI64_TO_IFID(in6) \ 74 do { (in6)->s6_addr[8] ^= EUI64_UBIT; } while (0) 75 76 struct protocol *protocols; 77 struct timeout *timeouts; 78 static struct timeout *free_timeouts; 79 static int interfaces_invalidated; 80 81 void (*bootp_packet_handler)(struct interface_info *, 82 void *, size_t, struct packet_ctx *); 83 84 static int interface_status(struct interface_info *ifinfo); 85 86 struct interface_info * 87 iflist_getbyindex(unsigned int index) 88 { 89 struct interface_info *intf; 90 91 TAILQ_FOREACH(intf, &intflist, entry) { 92 if (intf->index != index) 93 continue; 94 95 return intf; 96 } 97 98 return NULL; 99 } 100 101 struct interface_info * 102 iflist_getbyname(const char *name) 103 { 104 struct interface_info *intf; 105 106 TAILQ_FOREACH(intf, &intflist, entry) { 107 if (strcmp(intf->name, name) != 0) 108 continue; 109 110 return intf; 111 } 112 113 return NULL; 114 } 115 116 struct interface_info * 117 iflist_getbyaddr6(struct in6_addr *addr) 118 { 119 struct interface_info *intf; 120 121 TAILQ_FOREACH(intf, &intflist, entry) { 122 /* Look for link-layer address. */ 123 if (memcmp(&intf->linklocal, addr, sizeof(*addr)) == 0) 124 return intf; 125 } 126 127 return NULL; 128 } 129 130 void 131 setup_iflist(void) 132 { 133 struct interface_info *intf; 134 struct sockaddr_dl *sdl; 135 struct ifaddrs *ifap, *ifa; 136 struct if_data *ifi; 137 struct sockaddr_in *sin; 138 struct sockaddr_in6 *sin6; 139 140 TAILQ_INIT(&intflist); 141 if (getifaddrs(&ifap)) 142 fatalx("getifaddrs failed"); 143 144 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 145 if ((ifa->ifa_flags & IFF_LOOPBACK) || 146 (ifa->ifa_flags & IFF_POINTOPOINT)) 147 continue; 148 149 /* Find interface or create it. */ 150 intf = iflist_getbyname(ifa->ifa_name); 151 if (intf == NULL) { 152 intf = calloc(1, sizeof(*intf)); 153 if (intf == NULL) 154 fatal("calloc"); 155 156 strlcpy(intf->name, ifa->ifa_name, 157 sizeof(intf->name)); 158 TAILQ_INSERT_HEAD(&intflist, intf, entry); 159 } 160 161 /* Signal disabled interface. */ 162 if ((ifa->ifa_flags & IFF_UP) == 0) 163 intf->dead = 1; 164 165 if (ifa->ifa_addr->sa_family == AF_LINK) { 166 sdl = (struct sockaddr_dl *)ifa->ifa_addr; 167 ifi = (struct if_data *)ifa->ifa_data; 168 169 /* Skip non ethernet interfaces. */ 170 if (ifi->ifi_type != IFT_ETHER && 171 ifi->ifi_type != IFT_ENC) { 172 TAILQ_REMOVE(&intflist, intf, entry); 173 free(intf); 174 continue; 175 } 176 177 intf->index = sdl->sdl_index; 178 intf->hw_address.hlen = sdl->sdl_alen; 179 memcpy(intf->hw_address.haddr, 180 LLADDR(sdl), sdl->sdl_alen); 181 } else if (ifa->ifa_addr->sa_family == AF_INET) { 182 sin = (struct sockaddr_in *)ifa->ifa_addr; 183 if (sin->sin_addr.s_addr == htonl(INADDR_LOOPBACK) || 184 intf->primary_address.s_addr != INADDR_ANY) 185 continue; 186 187 intf->primary_address = sin->sin_addr; 188 } else if (ifa->ifa_addr->sa_family == AF_INET6) { 189 sin6 = (struct sockaddr_in6 *)ifa->ifa_addr; 190 /* Remove the scope from address if link-local. */ 191 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) { 192 intf->linklocal = sin6->sin6_addr; 193 intf->linklocal.s6_addr[2] = 0; 194 intf->linklocal.s6_addr[3] = 0; 195 } else 196 intf->gipv6 = 1; 197 198 /* At least one IPv6 address was found. */ 199 intf->ipv6 = 1; 200 } 201 } 202 203 freeifaddrs(ifap); 204 205 /* 206 * Generate link-local IPv6 address for interfaces without it. 207 * 208 * For IPv6 DHCP Relay it doesn't matter what is used for 209 * link-addr field, so let's generate an address that won't 210 * change during execution so we can always find the interface 211 * to relay packets back. This is only used for layer 2 relaying 212 * when the interface might not have an address. 213 */ 214 TAILQ_FOREACH(intf, &intflist, entry) { 215 if (memcmp(&intf->linklocal, &in6addr_any, 216 sizeof(in6addr_any)) != 0) 217 continue; 218 219 intf->linklocal.s6_addr[0] = 0xfe; 220 intf->linklocal.s6_addr[1] = 0x80; 221 intf->linklocal.s6_addr[8] = intf->hw_address.haddr[0]; 222 intf->linklocal.s6_addr[9] = intf->hw_address.haddr[1]; 223 intf->linklocal.s6_addr[10] = intf->hw_address.haddr[2]; 224 intf->linklocal.s6_addr[11] = 0xff; 225 intf->linklocal.s6_addr[12] = 0xfe; 226 intf->linklocal.s6_addr[13] = intf->hw_address.haddr[3]; 227 intf->linklocal.s6_addr[14] = intf->hw_address.haddr[4]; 228 intf->linklocal.s6_addr[15] = intf->hw_address.haddr[5]; 229 EUI64_TO_IFID(&intf->linklocal); 230 } 231 } 232 233 struct interface_info * 234 register_interface(const char *ifname, void (*handler)(struct protocol *)) 235 { 236 struct interface_info *intf; 237 238 if ((intf = iflist_getbyname(ifname)) == NULL) 239 return NULL; 240 241 /* Don't register disabled interfaces. */ 242 if (intf->dead) 243 return NULL; 244 245 /* Check if we already registered the interface. */ 246 if (intf->ifr.ifr_name[0] != 0) 247 return intf; 248 249 if (strlcpy(intf->ifr.ifr_name, ifname, 250 sizeof(intf->ifr.ifr_name)) >= sizeof(intf->ifr.ifr_name)) 251 fatalx("interface name '%s' too long", ifname); 252 253 if_register_receive(intf); 254 if_register_send(intf); 255 add_protocol(intf->name, intf->rfdesc, handler, intf); 256 257 return intf; 258 } 259 260 /* 261 * Wait for packets to come in using poll(). When a packet comes in, 262 * call receive_packet to receive the packet and possibly strip hardware 263 * addressing information from it, and then call through the 264 * bootp_packet_handler hook to try to do something with it. 265 */ 266 void 267 dispatch(void) 268 { 269 int count, i, to_msec, nfds = 0; 270 struct protocol *l; 271 struct pollfd *fds; 272 time_t howlong; 273 274 nfds = 0; 275 for (l = protocols; l; l = l->next) 276 nfds++; 277 278 fds = calloc(nfds, sizeof(struct pollfd)); 279 if (fds == NULL) 280 fatalx("Can't allocate poll structures."); 281 282 do { 283 /* 284 * Call any expired timeouts, and then if there's still 285 * a timeout registered, time out the select call then. 286 */ 287 another: 288 if (timeouts) { 289 if (timeouts->when <= cur_time) { 290 struct timeout *t = timeouts; 291 292 timeouts = timeouts->next; 293 (*(t->func))(t->what); 294 t->next = free_timeouts; 295 free_timeouts = t; 296 goto another; 297 } 298 299 /* 300 * Figure timeout in milliseconds, and check for 301 * potential overflow, so we can cram into an 302 * int for poll, while not polling with a 303 * negative timeout and blocking indefinitely. 304 */ 305 howlong = timeouts->when - cur_time; 306 if (howlong > INT_MAX / 1000) 307 howlong = INT_MAX / 1000; 308 to_msec = howlong * 1000; 309 } else 310 to_msec = -1; 311 312 /* Set up the descriptors to be polled. */ 313 i = 0; 314 315 for (l = protocols; l; l = l->next) { 316 struct interface_info *ip = l->local; 317 318 if (ip && (l->handler != got_one || !ip->dead)) { 319 fds[i].fd = l->fd; 320 fds[i].events = POLLIN; 321 fds[i].revents = 0; 322 i++; 323 } 324 } 325 326 if (i == 0) 327 fatalx("No live interfaces to poll on - exiting."); 328 329 /* Wait for a packet or a timeout... XXX */ 330 count = poll(fds, nfds, to_msec); 331 332 /* Not likely to be transitory... */ 333 if (count == -1) { 334 if (errno == EAGAIN || errno == EINTR) { 335 time(&cur_time); 336 continue; 337 } 338 else 339 fatal("poll"); 340 } 341 342 /* Get the current time... */ 343 time(&cur_time); 344 345 i = 0; 346 for (l = protocols; l; l = l->next) { 347 struct interface_info *ip = l->local; 348 349 if ((fds[i].revents & (POLLIN | POLLHUP))) { 350 fds[i].revents = 0; 351 if (ip && (l->handler != got_one || 352 !ip->dead)) 353 (*(l->handler))(l); 354 if (interfaces_invalidated) 355 break; 356 } 357 i++; 358 } 359 interfaces_invalidated = 0; 360 } while (1); 361 } 362 363 364 void 365 got_one(struct protocol *l) 366 { 367 struct packet_ctx pc; 368 ssize_t result; 369 uint8_t buf[4096]; 370 struct interface_info *ip = l->local; 371 372 memset(&pc, 0, sizeof(pc)); 373 374 if ((result = receive_packet(ip, buf, sizeof(buf), &pc)) == -1) { 375 log_warn("receive_packet failed on %s", ip->name); 376 ip->errors++; 377 if ((!interface_status(ip)) || 378 (ip->noifmedia && ip->errors > 20)) { 379 /* our interface has gone away. */ 380 log_warnx("Interface %s no longer appears valid.", 381 ip->name); 382 ip->dead = 1; 383 interfaces_invalidated = 1; 384 close(l->fd); 385 remove_protocol(l); 386 free(ip); 387 } 388 return; 389 } 390 if (result == 0) 391 return; 392 393 if (bootp_packet_handler) 394 (*bootp_packet_handler)(ip, buf, result, &pc); 395 } 396 397 int 398 interface_status(struct interface_info *ifinfo) 399 { 400 char *ifname = ifinfo->name; 401 int ifsock = ifinfo->rfdesc; 402 struct ifreq ifr; 403 struct ifmediareq ifmr; 404 405 /* get interface flags */ 406 memset(&ifr, 0, sizeof(ifr)); 407 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 408 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) == -1) { 409 log_warn("ioctl(SIOCGIFFLAGS) on %s", ifname); 410 goto inactive; 411 } 412 /* 413 * if one of UP and RUNNING flags is dropped, 414 * the interface is not active. 415 */ 416 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) { 417 goto inactive; 418 } 419 /* Next, check carrier on the interface, if possible */ 420 if (ifinfo->noifmedia) 421 goto active; 422 memset(&ifmr, 0, sizeof(ifmr)); 423 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 424 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) { 425 if (errno != EINVAL) { 426 log_debug("ioctl(SIOCGIFMEDIA) on %s", ifname); 427 ifinfo->noifmedia = 1; 428 goto active; 429 } 430 /* 431 * EINVAL (or ENOTTY) simply means that the interface 432 * does not support the SIOCGIFMEDIA ioctl. We regard it alive. 433 */ 434 ifinfo->noifmedia = 1; 435 goto active; 436 } 437 if (ifmr.ifm_status & IFM_AVALID) { 438 switch (ifmr.ifm_active & IFM_NMASK) { 439 case IFM_ETHER: 440 if (ifmr.ifm_status & IFM_ACTIVE) 441 goto active; 442 else 443 goto inactive; 444 break; 445 default: 446 goto inactive; 447 } 448 } 449 inactive: 450 return (0); 451 active: 452 return (1); 453 } 454 455 /* Add a protocol to the list of protocols... */ 456 void 457 add_protocol(char *name, int fd, void (*handler)(struct protocol *), 458 void *local) 459 { 460 struct protocol *p; 461 462 p = malloc(sizeof(*p)); 463 if (!p) 464 fatalx("can't allocate protocol struct for %s", name); 465 466 p->fd = fd; 467 p->handler = handler; 468 p->local = local; 469 p->next = protocols; 470 protocols = p; 471 } 472 473 void 474 remove_protocol(struct protocol *proto) 475 { 476 struct protocol *p, *next, *prev; 477 478 prev = NULL; 479 for (p = protocols; p; p = next) { 480 next = p->next; 481 if (p == proto) { 482 if (prev) 483 prev->next = p->next; 484 else 485 protocols = p->next; 486 free(p); 487 } 488 } 489 } 490