1 /* $OpenBSD: dispatch.c,v 1.39 2007/02/14 23:15:01 stevesk 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 "dhcpd.h"
43
44 #include <sys/ioctl.h>
45
46 #include <net/if_media.h>
47 #include <ifaddrs.h>
48 #include <poll.h>
49
50 struct timeout *timeouts;
51 static struct timeout *free_timeouts;
52 static int interfaces_invalidated;
53
54 static int interface_status(void);
55
56 /*
57 * Use getifaddrs() to get a list of all the attached interfaces. For
58 * each interface that's of type INET and not the loopback interface,
59 * register that interface with the network I/O software, figure out
60 * what subnet it's on, and add it to the list of interfaces.
61 */
62 void
discover_interface(void)63 discover_interface(void)
64 {
65 struct ifaddrs *ifap, *ifa;
66 struct ifreq *tif;
67 int len = IFNAMSIZ + sizeof(struct sockaddr_storage);
68
69 if (getifaddrs(&ifap) != 0)
70 error("getifaddrs failed");
71
72 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
73 if ((ifa->ifa_flags & IFF_LOOPBACK) ||
74 (ifa->ifa_flags & IFF_POINTOPOINT) ||
75 (!(ifa->ifa_flags & IFF_UP)))
76 continue;
77
78 if (strcmp(ifi->name, ifa->ifa_name))
79 continue;
80
81 /*
82 * If we have the capability, extract link information
83 * and record it in a linked list.
84 */
85 if (ifa->ifa_addr->sa_family == AF_LINK) {
86 struct sockaddr_dl *foo =
87 (struct sockaddr_dl *)ifa->ifa_addr;
88
89 ifi->index = foo->sdl_index;
90 ifi->hw_address.hlen = foo->sdl_alen;
91 ifi->hw_address.htype = HTYPE_ETHER; /* XXX */
92 memcpy(ifi->hw_address.haddr,
93 LLADDR(foo), foo->sdl_alen);
94 }
95 if (!ifi->ifp) {
96 if ((tif = malloc(len)) == NULL)
97 error("no space to remember ifp");
98 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ);
99 ifi->ifp = tif;
100 }
101 }
102
103 if (!ifi->ifp)
104 error("%s: not found", ifi->name);
105
106 /* Register the interface... */
107 if_register_receive();
108 if_register_send();
109 freeifaddrs(ifap);
110 }
111
112 void
reinitialize_interface(void)113 reinitialize_interface(void)
114 {
115 interfaces_invalidated = 1;
116 }
117
118 /*
119 * Wait for packets to come in using poll(). When a packet comes in, call
120 * receive_packet to receive the packet and possibly strip hardware addressing
121 * information from it, and then call do_packet to try to do something with it.
122 */
123 void
dispatch(void)124 dispatch(void)
125 {
126 int count, to_msec;
127 struct pollfd fds[2];
128 time_t howlong;
129
130 do {
131 /*
132 * Call any expired timeouts, and then if there's still
133 * a timeout registered, time out the select call then.
134 */
135 another:
136 if (timeouts) {
137 struct timeout *t;
138
139 if (timeouts->when <= cur_time) {
140 t = timeouts;
141 timeouts = timeouts->next;
142 (*(t->func))();
143 t->next = free_timeouts;
144 free_timeouts = t;
145 goto another;
146 }
147
148 /*
149 * Figure timeout in milliseconds, and check for
150 * potential overflow, so we can cram into an
151 * int for poll, while not polling with a
152 * negative timeout and blocking indefinitely.
153 */
154 howlong = timeouts->when - cur_time;
155 if (howlong > INT_MAX / 1000)
156 howlong = INT_MAX / 1000;
157 to_msec = howlong * 1000;
158 } else
159 to_msec = -1;
160
161 /* Set up the descriptors to be polled. */
162 if (!ifi || ifi->rfdesc == -1)
163 error("No live interface to poll on");
164
165 fds[0].fd = ifi->rfdesc;
166 fds[1].fd = routefd; /* Could be -1, which will be ignored. */
167 fds[0].events = fds[1].events = POLLIN;
168
169 /* Wait for a packet or a timeout... XXX */
170 count = poll(fds, 2, to_msec);
171
172 /* Get the current time... */
173 time(&cur_time);
174
175 /* Not likely to be transitory... */
176 if (count == -1) {
177 if (errno == EAGAIN || errno == EINTR) {
178 continue;
179 } else
180 error("poll: %m");
181 }
182
183 if ((fds[0].revents & (POLLIN | POLLHUP))) {
184 if (ifi && ifi->rfdesc != -1)
185 got_one();
186 }
187 if ((fds[1].revents & (POLLIN | POLLHUP))) {
188 if (ifi && !interfaces_invalidated)
189 routehandler();
190 }
191
192 interfaces_invalidated = 0;
193 } while (1);
194 }
195
196 void
got_one(void)197 got_one(void)
198 {
199 struct sockaddr_in from;
200 struct hardware hfrom;
201 struct iaddr ifrom;
202 ssize_t result;
203
204 if ((result = receive_packet(&from, &hfrom)) == -1) {
205 warning("receive_packet failed on %s: %s", ifi->name,
206 strerror(errno));
207 ifi->errors++;
208 if ((!interface_status()) ||
209 (ifi->noifmedia && ifi->errors > 20)) {
210 /* our interface has gone away. */
211 warning("Interface %s no longer appears valid.",
212 ifi->name);
213 interfaces_invalidated = 1;
214 close(ifi->rfdesc);
215 ifi->rfdesc = -1;
216 }
217 return;
218 }
219 if (result == 0)
220 return;
221
222 ifrom.len = 4;
223 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len);
224
225 do_packet(result, from.sin_port, ifrom, &hfrom);
226 }
227
228 int
interface_link_forceup(char * ifname)229 interface_link_forceup(char *ifname)
230 {
231 struct ifreq ifr;
232 int sock;
233
234 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
235 error("Can't create socket");
236
237 memset(&ifr, 0, sizeof(ifr));
238 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
239 if (ioctl(sock, SIOCGIFFLAGS, (caddr_t)&ifr) == -1) {
240 close(sock);
241 return (-1);
242 }
243
244 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
245 ifr.ifr_flags |= IFF_UP;
246 if (ioctl(sock, SIOCSIFFLAGS, (caddr_t)&ifr) == -1) {
247 close(sock);
248 return (-1);
249 }
250 close(sock);
251 return (0);
252 }
253 close(sock);
254 return (1);
255 }
256
257 void
interface_link_forcedown(char * ifname)258 interface_link_forcedown(char *ifname)
259 {
260 struct ifreq ifr;
261 int sock;
262
263 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
264 error("Can't create socket");
265
266 memset(&ifr, 0, sizeof(ifr));
267 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
268 if (ioctl(sock, SIOCGIFFLAGS, (caddr_t)&ifr) == -1) {
269 close(sock);
270 return;
271 }
272
273 if ((ifr.ifr_flags & IFF_UP) == IFF_UP) {
274 ifr.ifr_flags &= ~IFF_UP;
275 if (ioctl(sock, SIOCSIFFLAGS, (caddr_t)&ifr) == -1) {
276 close(sock);
277 return;
278 }
279 }
280
281 close(sock);
282 }
283
284 int
interface_status(void)285 interface_status(void)
286 {
287 char *ifname = ifi->name;
288 int ifsock = ifi->rfdesc;
289 struct ifreq ifr;
290 struct ifmediareq ifmr;
291
292 /* get interface flags */
293 memset(&ifr, 0, sizeof(ifr));
294 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
295 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) {
296 warning("ioctl(SIOCGIFFLAGS) on %s: %m", ifname);
297 goto inactive;
298 }
299
300 /*
301 * if one of UP and RUNNING flags is dropped,
302 * the interface is not active.
303 */
304 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
305 goto inactive;
306
307 /* Next, check carrier on the interface, if possible */
308 if (ifi->noifmedia)
309 goto active;
310 memset(&ifmr, 0, sizeof(ifmr));
311 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
312 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) {
313 if (errno != EINVAL) {
314 debug("ioctl(SIOCGIFMEDIA) on %s: %m", ifname);
315
316 ifi->noifmedia = 1;
317 goto active;
318 }
319 /*
320 * EINVAL (or ENOTTY) simply means that the interface
321 * does not support the SIOCGIFMEDIA ioctl. We regard it alive.
322 */
323 ifi->noifmedia = 1;
324 goto active;
325 }
326 if (ifmr.ifm_status & IFM_AVALID) {
327 switch (ifmr.ifm_active & IFM_NMASK) {
328 case IFM_ETHER:
329 if (ifmr.ifm_status & IFM_ACTIVE)
330 goto active;
331 else
332 goto inactive;
333 break;
334 default:
335 goto inactive;
336 }
337 }
338 inactive:
339 return (0);
340 active:
341 return (1);
342 }
343
344 void
add_timeout(time_t when,void (* where)(void))345 add_timeout(time_t when, void (*where)(void))
346 {
347 struct timeout *t, *q;
348
349 /* See if this timeout supersedes an existing timeout. */
350 t = NULL;
351 for (q = timeouts; q; q = q->next) {
352 if (q->func == where) {
353 if (t)
354 t->next = q->next;
355 else
356 timeouts = q->next;
357 break;
358 }
359 t = q;
360 }
361
362 /* If we didn't supersede a timeout, allocate a timeout
363 structure now. */
364 if (!q) {
365 if (free_timeouts) {
366 q = free_timeouts;
367 free_timeouts = q->next;
368 q->func = where;
369 } else {
370 q = malloc(sizeof(struct timeout));
371 if (!q)
372 error("Can't allocate timeout structure!");
373 q->func = where;
374 }
375 }
376
377 q->when = when;
378
379 /* Now sort this timeout into the timeout list. */
380
381 /* Beginning of list? */
382 if (!timeouts || timeouts->when > q->when) {
383 q->next = timeouts;
384 timeouts = q;
385 return;
386 }
387
388 /* Middle of list? */
389 for (t = timeouts; t->next; t = t->next) {
390 if (t->next->when > q->when) {
391 q->next = t->next;
392 t->next = q;
393 return;
394 }
395 }
396
397 /* End of list. */
398 t->next = q;
399 q->next = NULL;
400 }
401
402 void
cancel_timeout(void (* where)(void))403 cancel_timeout(void (*where)(void))
404 {
405 struct timeout *t, *q;
406
407 /* Look for this timeout on the list, and unlink it if we find it. */
408 t = NULL;
409 for (q = timeouts; q; q = q->next) {
410 if (q->func == where) {
411 if (t)
412 t->next = q->next;
413 else
414 timeouts = q->next;
415 break;
416 }
417 t = q;
418 }
419
420 /* If we found the timeout, put it on the free list. */
421 if (q) {
422 q->next = free_timeouts;
423 free_timeouts = q;
424 }
425 }
426
427 int
interface_link_status(char * ifname)428 interface_link_status(char *ifname)
429 {
430 struct ifmediareq ifmr;
431 int sock;
432
433 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
434 error("Can't create socket");
435
436 memset(&ifmr, 0, sizeof(ifmr));
437 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
438 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) {
439 /* EINVAL -> link state unknown. treat as active */
440 if (errno != EINVAL)
441 debug("ioctl(SIOCGIFMEDIA) on %s: %m", ifname);
442 close(sock);
443 return (1);
444 }
445 close(sock);
446
447 if (ifmr.ifm_status & IFM_AVALID) {
448 if ((ifmr.ifm_active & IFM_NMASK) == IFM_ETHER) {
449 if (ifmr.ifm_status & IFM_ACTIVE)
450 return (1);
451 else
452 return (0);
453 }
454 }
455 return (1);
456 }
457