1 /* $OpenBSD: src/sbin/dhclient/dispatch.c,v 1.59 2012/10/11 08:05:05 sthen 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
53 /*
54 * Use getifaddrs() to get a list of all the attached interfaces. Find
55 * our interface on the list and store the interesting information about it.
56 */
57 void
discover_interface(void)58 discover_interface(void)
59 {
60 struct ifaddrs *ifap, *ifa;
61 struct ifreq *tif;
62 int len = IFNAMSIZ + sizeof(struct sockaddr_storage);
63
64 if (getifaddrs(&ifap) != 0)
65 error("getifaddrs failed");
66
67 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
68 if ((ifa->ifa_flags & IFF_LOOPBACK) ||
69 (ifa->ifa_flags & IFF_POINTOPOINT) ||
70 (!(ifa->ifa_flags & IFF_UP)))
71 continue;
72
73 if (strcmp(ifi->name, ifa->ifa_name))
74 continue;
75
76 /*
77 * If we have the capability, extract & save link information.
78 */
79 if (ifa->ifa_addr->sa_family == AF_LINK) {
80 struct sockaddr_dl *foo =
81 (struct sockaddr_dl *)ifa->ifa_addr;
82
83 ifi->index = foo->sdl_index;
84 ifi->hw_address.hlen = foo->sdl_alen;
85 ifi->hw_address.htype = HTYPE_ETHER; /* XXX */
86 memcpy(ifi->hw_address.haddr,
87 LLADDR(foo), foo->sdl_alen);
88 }
89 if (!ifi->ifp) {
90 if ((tif = malloc(len)) == NULL)
91 error("no space to remember ifp");
92 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ);
93 ifi->ifp = tif;
94 }
95 }
96
97 if (!ifi->ifp)
98 error("%s: not found", ifi->name);
99
100 /* Register the interface... */
101 if_register_receive();
102 if_register_send();
103 freeifaddrs(ifap);
104 }
105
106 /*
107 * Loop waiting for packets, timeouts or routing messages.
108 */
109 void
dispatch(void)110 dispatch(void)
111 {
112 int count, to_msec;
113 struct pollfd fds[2];
114 time_t cur_time, howlong;
115 void (*func)(void);
116
117 do {
118 /*
119 * Call expired timeout, and then if there's still
120 * a timeout registered, time out the select call then.
121 */
122 another:
123 if (!ifi)
124 error("No interfaces available");
125
126 if (timeout.func) {
127 time(&cur_time);
128 if (timeout.when <= cur_time) {
129 func = timeout.func;
130 cancel_timeout();
131 (*(func))();
132 goto another;
133 }
134 /*
135 * Figure timeout in milliseconds, and check for
136 * potential overflow, so we can cram into an
137 * int for poll, while not polling with a
138 * negative timeout and blocking indefinitely.
139 */
140 howlong = timeout.when - cur_time;
141 if (howlong > INT_MAX / 1000)
142 howlong = INT_MAX / 1000;
143 to_msec = howlong * 1000;
144 } else
145 to_msec = -1;
146
147 /* Set up the descriptors to be polled. */
148 if (!ifi || ifi->rfdesc == -1)
149 error("No live interface to poll on");
150
151 fds[0].fd = ifi->rfdesc;
152 fds[1].fd = routefd; /* Could be -1, which will be ignored. */
153 fds[0].events = fds[1].events = POLLIN;
154
155 /* Wait for a packet or a timeout... XXX */
156 count = poll(fds, 2, to_msec);
157
158 /* Not likely to be transitory... */
159 if (count == -1) {
160 if (errno == EAGAIN || errno == EINTR) {
161 continue;
162 } else
163 error("poll: %m");
164 }
165
166 if ((fds[0].revents & (POLLIN | POLLHUP))) {
167 /* XXX profmakx: I am not sure whether updating the linkstate
168 here is the best idea, but it being not up to date leads
169 to a busy loop.
170 Alternatively we can just remove the link state check since
171 the link state is checked in got_one() later on
172 */
173 ifi->linkstat = interface_status(ifi->name);
174
175 if (ifi && ifi->linkstat && ifi->rfdesc != -1)
176 got_one();
177 }
178 if ((fds[1].revents & (POLLIN | POLLHUP))) {
179 if (ifi)
180 routehandler();
181 }
182 } while (1);
183 }
184
185 void
got_one(void)186 got_one(void)
187 {
188 struct sockaddr_in from;
189 struct hardware hfrom;
190 struct iaddr ifrom;
191 ssize_t result;
192
193 if ((result = receive_packet(&from, &hfrom)) == -1) {
194 warning("receive_packet failed on %s: %s", ifi->name,
195 strerror(errno));
196 ifi->errors++;
197 if ((!interface_status(ifi->name)) ||
198 (ifi->noifmedia && ifi->errors > 20)) {
199 /* our interface has gone away. */
200 error("Interface %s no longer appears valid.",
201 ifi->name);
202 }
203 return;
204 }
205 if (result == 0)
206 return;
207
208 ifrom.len = 4;
209 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len);
210
211 do_packet(result, from.sin_port, ifrom, &hfrom);
212 }
213
214 /*
215 * Normally its ok to force the interface link up, but don't do it
216 * if it is an 80211 interface.
217 */
218 int
interface_link_forceup(char * ifname)219 interface_link_forceup(char *ifname)
220 {
221 struct ifreq ifr;
222 struct ifmediareq ifmr;
223 int sock;
224
225 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
226 error("Can't create socket");
227
228 memset(&ifr, 0, sizeof(ifr));
229 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
230 if (ioctl(sock, SIOCGIFFLAGS, (caddr_t)&ifr) == -1) {
231 close(sock);
232 return (-1);
233 }
234 memset(&ifmr, 0, sizeof(ifmr));
235 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
236 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) != -1) {
237 if (IFM_TYPE(ifmr.ifm_active) == IFM_IEEE80211) {
238 return 0;
239 }
240 }
241
242 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
243 ifr.ifr_flags |= IFF_UP;
244 if (ioctl(sock, SIOCSIFFLAGS, (caddr_t)&ifr) == -1) {
245 close(sock);
246 return (-1);
247 }
248 close(sock);
249 return (0);
250 }
251 close(sock);
252 return (1);
253 }
254
255 int
interface_status(char * ifname)256 interface_status(char *ifname)
257 {
258 struct ifreq ifr;
259 struct ifmediareq ifmr;
260 int sock;
261
262 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
263 error("Can't create socket");
264
265 /* get interface flags */
266 memset(&ifr, 0, sizeof(ifr));
267 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
268 if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) {
269 error("ioctl(SIOCGIFFLAGS) on %s: %m", ifname);
270 }
271
272 /*
273 * if one of UP and RUNNING flags is dropped,
274 * the interface is not active.
275 */
276 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
277 goto inactive;
278
279 /* Next, check carrier on the interface, if possible */
280 if (ifi->noifmedia)
281 goto active;
282 memset(&ifmr, 0, sizeof(ifmr));
283 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
284 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) {
285 /*
286 * EINVAL or ENOTTY simply means that the interface
287 * does not support the SIOCGIFMEDIA ioctl. We regard it alive.
288 */
289 #ifdef DEBUG
290 if (errno != EINVAL && errno != ENOTTY)
291 debug("ioctl(SIOCGIFMEDIA) on %s: %m", ifname);
292 #endif
293 ifi->noifmedia = 1;
294 goto active;
295 }
296 if (ifmr.ifm_status & IFM_AVALID) {
297 if (ifmr.ifm_status & IFM_ACTIVE)
298 goto active;
299 else
300 goto inactive;
301 }
302
303 /* Assume 'active' if IFM_AVALID is not set. */
304
305 active:
306 close(sock);
307 return (1);
308 inactive:
309 close(sock);
310 return (0);
311 }
312
313 void
set_timeout(time_t when,void (* where)(void))314 set_timeout(time_t when, void (*where)(void))
315 {
316 timeout.when = when;
317 timeout.func = where;
318 }
319
320 void
set_timeout_interval(time_t secs,void (* where)(void))321 set_timeout_interval(time_t secs, void (*where)(void))
322 {
323 timeout.when = time(NULL) + secs;
324 timeout.func = where;
325 }
326
327 void
cancel_timeout(void)328 cancel_timeout(void)
329 {
330 timeout.when = 0;
331 timeout.func = NULL;
332 }
333
334 int
subnet_exists(struct client_lease * l)335 subnet_exists(struct client_lease *l)
336 {
337 struct ifaddrs *ifap, *ifa;
338 in_addr_t mymask, myaddr, mynet, hismask, hisaddr, hisnet;
339
340 bcopy(l->options[DHO_SUBNET_MASK].data, &mymask, 4);
341 bcopy(l->address.iabuf, &myaddr, 4);
342 mynet = mymask & myaddr;
343
344 if (getifaddrs(&ifap) != 0)
345 error("getifaddrs failed");
346
347 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
348 if (strcmp(ifi->name, ifa->ifa_name) == 0)
349 continue;
350
351 if (ifa->ifa_addr->sa_family != AF_INET)
352 continue;
353
354 hismask = ((struct sockaddr_in *)ifa->ifa_netmask)->
355 sin_addr.s_addr;
356 hisaddr = ((struct sockaddr_in *)ifa->ifa_addr)->
357 sin_addr.s_addr;
358 hisnet = hisaddr & hismask;
359
360 if (hisnet == 0)
361 continue;
362
363 /* Would his packets go out *my* interface? */
364 if (mynet == (hisaddr & mymask)) {
365 note("interface %s already has the offered subnet!",
366 ifa->ifa_name);
367 return (1);
368 }
369
370 /* Would my packets go out *his* interface? */
371 if (hisnet == (myaddr & hismask)) {
372 note("interface %s already has the offered subnet!",
373 ifa->ifa_name);
374 return (1);
375 }
376 }
377
378 freeifaddrs(ifap);
379
380 return (0);
381 }
382