| 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 | } |