1 /* $OpenBSD: src/sbin/dhclient/dispatch.c,v 1.53 2012/07/26 18:42:58 krw 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/ioctl.h> 43 44 #include <net/if_media.h> 45 46 #include <ifaddrs.h> 47 #include <poll.h> 48 49 #include "dhcpd.h" 50 51 struct timeout timeout; 52 static int interfaces_invalidated; 53 54 /* 55 * Use getifaddrs() to get a list of all the attached interfaces. For 56 * each interface that's of type INET and not the loopback interface, 57 * register that interface with the network I/O software, figure out 58 * what subnet it's on, and add it to the list of interfaces. 59 */ 60 void 61 discover_interface(void) 62 { 63 struct ifaddrs *ifap, *ifa; 64 struct ifreq *tif; 65 int len = IFNAMSIZ + sizeof(struct sockaddr_storage); 66 67 if (getifaddrs(&ifap) != 0) 68 error("getifaddrs failed"); 69 70 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { 71 if ((ifa->ifa_flags & IFF_LOOPBACK) || 72 (ifa->ifa_flags & IFF_POINTOPOINT) || 73 (!(ifa->ifa_flags & IFF_UP))) 74 continue; 75 76 if (strcmp(ifi->name, ifa->ifa_name)) 77 continue; 78 79 /* 80 * If we have the capability, extract link information 81 * and record it in a linked list. 82 */ 83 if (ifa->ifa_addr->sa_family == AF_LINK) { 84 struct sockaddr_dl *foo = 85 (struct sockaddr_dl *)ifa->ifa_addr; 86 87 ifi->index = foo->sdl_index; 88 ifi->hw_address.hlen = foo->sdl_alen; 89 ifi->hw_address.htype = HTYPE_ETHER; /* XXX */ 90 memcpy(ifi->hw_address.haddr, 91 LLADDR(foo), foo->sdl_alen); 92 } 93 if (!ifi->ifp) { 94 if ((tif = malloc(len)) == NULL) 95 error("no space to remember ifp"); 96 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ); 97 ifi->ifp = tif; 98 } 99 } 100 101 if (!ifi->ifp) 102 error("%s: not found", ifi->name); 103 104 /* Register the interface... */ 105 if_register_receive(); 106 if_register_send(); 107 freeifaddrs(ifap); 108 } 109 110 void 111 reinitialize_interface(void) 112 { 113 interfaces_invalidated = 1; 114 } 115 116 /* 117 * Wait for packets to come in using poll(). When a packet comes in, call 118 * receive_packet to receive the packet and possibly strip hardware addressing 119 * information from it, and then call do_packet to try to do something with it. 120 */ 121 void 122 dispatch(void) 123 { 124 int count, to_msec; 125 struct pollfd fds[2]; 126 time_t howlong; 127 void (*func)(void); 128 129 do { 130 /* 131 * Call expired timeout, and then if there's still 132 * a timeout registered, time out the select call then. 133 */ 134 another: 135 if (!ifi) 136 error("No interfaces available"); 137 138 if (!ifi->linkstat) 139 interfaces_invalidated = 0; 140 141 if (timeout.func) { 142 time(&cur_time); 143 if (timeout.when <= cur_time) { 144 func = timeout.func; 145 cancel_timeout(); 146 (*(func))(); 147 goto another; 148 } 149 /* 150 * Figure timeout in milliseconds, and check for 151 * potential overflow, so we can cram into an 152 * int for poll, while not polling with a 153 * negative timeout and blocking indefinitely. 154 */ 155 howlong = timeout.when - cur_time; 156 if (howlong > INT_MAX / 1000) 157 howlong = INT_MAX / 1000; 158 to_msec = howlong * 1000; 159 } else 160 to_msec = -1; 161 162 /* Set up the descriptors to be polled. */ 163 if (!ifi || ifi->rfdesc == -1) 164 error("No live interface to poll on"); 165 166 fds[0].fd = ifi->rfdesc; 167 fds[1].fd = routefd; /* Could be -1, which will be ignored. */ 168 fds[0].events = fds[1].events = POLLIN; 169 170 /* Wait for a packet or a timeout... XXX */ 171 count = poll(fds, 2, to_msec); 172 173 /* Not likely to be transitory... */ 174 if (count == -1) { 175 if (errno == EAGAIN || errno == EINTR) { 176 continue; 177 } else 178 error("poll: %m"); 179 } 180 181 if ((fds[0].revents & (POLLIN | POLLHUP))) { 182 if (ifi && ifi->linkstat && ifi->rfdesc != -1) 183 got_one(); 184 } 185 if ((fds[1].revents & (POLLIN | POLLHUP))) { 186 if (ifi && !interfaces_invalidated) 187 routehandler(); 188 } 189 190 interfaces_invalidated = 0; 191 } while (1); 192 } 193 194 void 195 got_one(void) 196 { 197 struct sockaddr_in from; 198 struct hardware hfrom; 199 struct iaddr ifrom; 200 ssize_t result; 201 202 if ((result = receive_packet(&from, &hfrom)) == -1) { 203 warning("receive_packet failed on %s: %s", ifi->name, 204 strerror(errno)); 205 ifi->errors++; 206 if ((!interface_status(ifi->name)) || 207 (ifi->noifmedia && ifi->errors > 20)) { 208 /* our interface has gone away. */ 209 error("Interface %s no longer appears valid.", 210 ifi->name); 211 } 212 return; 213 } 214 if (result == 0) 215 return; 216 217 ifrom.len = 4; 218 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len); 219 220 do_packet(result, from.sin_port, ifrom, &hfrom); 221 } 222 223 int 224 interface_link_forceup(char *ifname) 225 { 226 struct ifreq ifr; 227 int sock; 228 229 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 230 error("Can't create socket"); 231 232 memset(&ifr, 0, sizeof(ifr)); 233 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 234 if (ioctl(sock, SIOCGIFFLAGS, (caddr_t)&ifr) == -1) { 235 close(sock); 236 return (-1); 237 } 238 239 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) { 240 ifr.ifr_flags |= IFF_UP; 241 if (ioctl(sock, SIOCSIFFLAGS, (caddr_t)&ifr) == -1) { 242 close(sock); 243 return (-1); 244 } 245 close(sock); 246 return (0); 247 } 248 close(sock); 249 return (1); 250 } 251 252 int 253 interface_status(char *ifname) 254 { 255 struct ifreq ifr; 256 struct ifmediareq ifmr; 257 int sock; 258 259 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 260 error("Can't create socket"); 261 262 /* get interface flags */ 263 memset(&ifr, 0, sizeof(ifr)); 264 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 265 if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) { 266 error("ioctl(SIOCGIFFLAGS) on %s: %m", ifname); 267 } 268 269 /* 270 * if one of UP and RUNNING flags is dropped, 271 * the interface is not active. 272 */ 273 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) 274 goto inactive; 275 276 /* Next, check carrier on the interface, if possible */ 277 if (ifi->noifmedia) 278 goto active; 279 memset(&ifmr, 0, sizeof(ifmr)); 280 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name)); 281 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) { 282 /* 283 * EINVAL or ENOTTY simply means that the interface 284 * does not support the SIOCGIFMEDIA ioctl. We regard it alive. 285 */ 286 #ifdef DEBUG 287 if (errno != EINVAL && errno != ENOTTY) 288 debug("ioctl(SIOCGIFMEDIA) on %s: %m", ifname); 289 #endif 290 ifi->noifmedia = 1; 291 goto active; 292 } 293 if (ifmr.ifm_status & IFM_AVALID) { 294 if (ifmr.ifm_status & IFM_ACTIVE) 295 goto active; 296 else 297 goto inactive; 298 } 299 300 /* Assume 'active' if IFM_AVALID is not set. */ 301 302 active: 303 close(sock); 304 return (1); 305 inactive: 306 close(sock); 307 return (0); 308 } 309 310 void 311 set_timeout(time_t when, void (*where)(void)) 312 { 313 timeout.when = when; 314 timeout.func = where; 315 } 316 317 void 318 cancel_timeout(void) 319 { 320 timeout.when = 0; 321 timeout.func = NULL; 322 } 323