1 /*
2 * dhcpcd - DHCP client daemon
3 * Copyright 2006-2008 Roy Marples <roy@marples.name>
4 * All rights reserved
5
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/stat.h>
29 #include <sys/wait.h>
30
31 #include <netinet/in.h>
32 #include <arpa/inet.h>
33
34 #include <ctype.h>
35 #include <errno.h>
36 #include <signal.h>
37 #include <stdlib.h>
38 #include <unistd.h>
39
40 #include "config.h"
41 #include "common.h"
42 #include "configure.h"
43 #include "dhcp.h"
44 #include "dhcpcd.h"
45 #include "logger.h"
46 #include "net.h"
47 #include "signals.h"
48
49 #define DEFAULT_PATH "PATH=/usr/bin:/usr/sbin:/bin:/sbin"
50
51
52 static int
exec_script(char * const * argv,char * const * env)53 exec_script(char *const *argv, char *const *env)
54 {
55 pid_t pid;
56 sigset_t full;
57 sigset_t old;
58
59 /* OK, we need to block signals */
60 sigfillset(&full);
61 sigprocmask(SIG_SETMASK, &full, &old);
62 signal_reset();
63
64 switch (pid = vfork()) {
65 case -1:
66 logger(LOG_ERR, "vfork: %s", strerror(errno));
67 break;
68 case 0:
69 sigprocmask(SIG_SETMASK, &old, NULL);
70 execve(argv[0], argv, env);
71 logger(LOG_ERR, "%s: %s", argv[0], strerror(errno));
72 _exit(127);
73 /* NOTREACHED */
74 }
75
76 /* Restore our signals */
77 signal_setup();
78 sigprocmask(SIG_SETMASK, &old, NULL);
79 return pid;
80 }
81
82 int
run_script(const struct options * options,const char * iface,const char * reason,const struct dhcp_message * dhcpn,const struct dhcp_message * dhcpo)83 run_script(const struct options *options, const char *iface,
84 const char *reason,
85 const struct dhcp_message *dhcpn, const struct dhcp_message *dhcpo)
86 {
87 char *const argv[2] = { UNCONST(options->script), NULL };
88 char **env = NULL, **ep;
89 char *path;
90 ssize_t e, elen;
91 pid_t pid;
92 int status = 0;
93
94 logger(LOG_DEBUG, "executing `%s', reason %s", options->script, reason);
95
96 /* Make our env */
97 elen = 5;
98 env = xmalloc(sizeof(char *) * (elen + 1));
99 path = getenv("PATH");
100 if (path) {
101 e = strlen("PATH") + strlen(path) + 2;
102 env[0] = xmalloc(e);
103 snprintf(env[0], e, "PATH=%s", path);
104 } else
105 env[0] = xstrdup(DEFAULT_PATH);
106 e = strlen("interface") + strlen(iface) + 2;
107 env[1] = xmalloc(e);
108 snprintf(env[1], e, "interface=%s", iface);
109 e = strlen("reason") + strlen(reason) + 2;
110 env[2] = xmalloc(e);
111 snprintf(env[2], e, "reason=%s", reason);
112 e = 20;
113 env[3] = xmalloc(e);
114 snprintf(env[3], e, "pid=%d", getpid());
115 env[4] = xmalloc(e);
116 snprintf(env[4], e, "metric=%d", options->metric);
117 if (dhcpo) {
118 e = configure_env(NULL, NULL, dhcpo, options);
119 if (e > 0) {
120 env = xrealloc(env, sizeof(char *) * (elen + e + 1));
121 elen += configure_env(env + elen, "old", dhcpo, options);
122 }
123 }
124 if (dhcpn) {
125 e = configure_env(NULL, NULL, dhcpn, options);
126 if (e > 0) {
127 env = xrealloc(env, sizeof(char *) * (elen + e + 1));
128 elen += configure_env(env + elen, "new", dhcpn, options);
129 }
130 }
131 /* Add our base environment */
132 if (options->environ) {
133 e = 0;
134 while (options->environ[e++])
135 ;
136 env = xrealloc(env, sizeof(char *) * (elen + e + 1));
137 e = 0;
138 while (options->environ[e]) {
139 env[elen + e] = xstrdup(options->environ[e]);
140 e++;
141 }
142 elen += e;
143 }
144 env[elen] = '\0';
145
146 pid = exec_script(argv, env);
147 if (pid == -1)
148 status = -1;
149 else if (pid != 0) {
150 /* Wait for the script to finish */
151 while (waitpid(pid, &status, 0) == -1) {
152 if (errno != EINTR) {
153 logger(LOG_ERR, "waitpid: %s", strerror(errno));
154 status = -1;
155 break;
156 }
157 }
158 }
159
160 /* Cleanup */
161 ep = env;
162 while (*ep)
163 free(*ep++);
164 free(env);
165 return status;
166 }
167
168 static struct rt *
reverse_routes(struct rt * routes)169 reverse_routes(struct rt *routes)
170 {
171 struct rt *rt;
172 struct rt *rtn = NULL;
173
174 while (routes) {
175 rt = routes->next;
176 routes->next = rtn;
177 rtn = routes;
178 routes = rt;
179 }
180 return rtn;
181 }
182
183 static int
delete_route(const char * iface,struct rt * rt,int metric)184 delete_route(const char *iface, struct rt *rt, int metric)
185 {
186 char *addr;
187 int retval;
188
189 addr = xstrdup(inet_ntoa(rt->dest));
190 logger(LOG_DEBUG, "deleting route %s/%d via %s",
191 addr, inet_ntocidr(rt->net), inet_ntoa(rt->gate));
192 free(addr);
193 retval = del_route(iface, &rt->dest, &rt->net, &rt->gate, metric);
194 if (retval != 0 && errno != ENOENT && errno != ESRCH)
195 logger(LOG_ERR," del_route: %s", strerror(errno));
196 return retval;
197 }
198
199 static int
delete_routes(struct interface * iface,int metric)200 delete_routes(struct interface *iface, int metric)
201 {
202 struct rt *rt;
203 struct rt *rtn;
204 int retval = 0;
205
206 rt = reverse_routes(iface->routes);
207 while (rt) {
208 rtn = rt->next;
209 retval += delete_route(iface->name, rt, metric);
210 free(rt);
211 rt = rtn;
212 }
213 iface->routes = NULL;
214
215 return retval;
216 }
217
218 static int
in_routes(const struct rt * routes,const struct rt * rt)219 in_routes(const struct rt *routes, const struct rt *rt)
220 {
221 while (routes) {
222 if (routes->dest.s_addr == rt->dest.s_addr &&
223 routes->net.s_addr == rt->net.s_addr &&
224 routes->gate.s_addr == rt->gate.s_addr)
225 return 0;
226 routes = routes->next;
227 }
228 return -1;
229 }
230
231 static int
configure_routes(struct interface * iface,const struct dhcp_message * dhcp,const struct options * options)232 configure_routes(struct interface *iface, const struct dhcp_message *dhcp,
233 const struct options *options)
234 {
235 struct rt *rt, *ort;
236 struct rt *rtn = NULL, *nr = NULL;
237 int remember;
238 int retval = 0;
239 char *addr;
240
241 ort = get_option_routes(dhcp);
242
243 #ifdef IPV4LL_ALWAYSROUTE
244 if (options->options & DHCPCD_IPV4LL &&
245 IN_PRIVATE(ntohl(dhcp->yiaddr)))
246 {
247 for (rt = ort; rt; rt = rt->next) {
248 /* Check if we have already got a link locale route
249 * dished out by the DHCP server */
250 if (rt->dest.s_addr == htonl(LINKLOCAL_ADDR) &&
251 rt->net.s_addr == htonl(LINKLOCAL_MASK))
252 break;
253 rtn = rt;
254 }
255
256 if (!rt) {
257 rt = xmalloc(sizeof(*rt));
258 rt->dest.s_addr = htonl(LINKLOCAL_ADDR);
259 rt->net.s_addr = htonl(LINKLOCAL_MASK);
260 rt->gate.s_addr = 0;
261 rt->next = NULL;
262 if (rtn)
263 rtn->next = rt;
264 else
265 ort = rt;
266 }
267 }
268 #endif
269
270 /* Now remove old routes we no longer use.
271 * We should do this in reverse order. */
272 iface->routes = reverse_routes(iface->routes);
273 for (rt = iface->routes; rt; rt = rt->next)
274 if (in_routes(ort, rt) != 0)
275 delete_route(iface->name, rt, options->metric);
276
277 for (rt = ort; rt; rt = rt->next) {
278 /* Don't set default routes if not asked to */
279 if (rt->dest.s_addr == 0 &&
280 rt->net.s_addr == 0 &&
281 !(options->options & DHCPCD_GATEWAY))
282 continue;
283
284 addr = xstrdup(inet_ntoa(rt->dest));
285 logger(LOG_DEBUG, "adding route to %s/%d via %s",
286 addr, inet_ntocidr(rt->net), inet_ntoa(rt->gate));
287 free(addr);
288 remember = add_route(iface->name, &rt->dest,
289 &rt->net, &rt->gate,
290 options->metric);
291 retval += remember;
292
293 /* If we failed to add the route, we may have already added it
294 ourselves. If so, remember it again. */
295 if (remember < 0) {
296 if (errno != EEXIST)
297 logger(LOG_ERR, "add_route: %s",
298 strerror(errno));
299 if (in_routes(iface->routes, rt) == 0)
300 remember = 1;
301 }
302
303 /* This login is split from above due to the #ifdef below */
304 if (remember >= 0) {
305 if (nr) {
306 rtn->next = xmalloc(sizeof(*rtn));
307 rtn = rtn->next;
308 } else {
309 nr = rtn = xmalloc(sizeof(*rtn));
310 }
311 rtn->dest.s_addr = rt->dest.s_addr;
312 rtn->net.s_addr = rt->net.s_addr;
313 rtn->gate.s_addr = rt->gate.s_addr;
314 rtn->next = NULL;
315 }
316 }
317 free_routes(ort);
318 free_routes(iface->routes);
319 iface->routes = nr;
320 return retval;
321 }
322
323 static int
delete_address(struct interface * iface)324 delete_address(struct interface *iface)
325 {
326 int retval;
327 logger(LOG_DEBUG, "deleting IP address %s/%d",
328 inet_ntoa(iface->addr),
329 inet_ntocidr(iface->net));
330 retval = del_address(iface->name, &iface->addr, &iface->net);
331 if (retval == -1 && errno != EADDRNOTAVAIL)
332 logger(LOG_ERR, "del_address: %s", strerror(errno));
333 iface->addr.s_addr = 0;
334 iface->net.s_addr = 0;
335 return retval;
336 }
337
338 int
configure(struct interface * iface,const char * reason,const struct dhcp_message * dhcp,const struct dhcp_message * old,const struct dhcp_lease * lease,const struct options * options,int up)339 configure(struct interface *iface, const char *reason,
340 const struct dhcp_message *dhcp, const struct dhcp_message *old,
341 const struct dhcp_lease *lease, const struct options *options,
342 int up)
343 {
344 struct in_addr addr;
345 struct in_addr net;
346 struct in_addr brd;
347 #ifdef __linux__
348 struct in_addr dest;
349 struct in_addr gate;
350 #endif
351
352 /* Grab our IP config */
353 if (dhcp == NULL)
354 up = 0;
355 else {
356 addr.s_addr = dhcp->yiaddr;
357 if (addr.s_addr == 0)
358 addr.s_addr = lease->addr.s_addr;
359 /* Ensure we have all the needed values */
360 if (get_option_addr(&net.s_addr, dhcp, DHO_SUBNETMASK) == -1)
361 net.s_addr = get_netmask(addr.s_addr);
362 if (get_option_addr(&brd.s_addr, dhcp, DHO_BROADCAST) == -1)
363 brd.s_addr = addr.s_addr | ~net.s_addr;
364 }
365
366 /* If we aren't up, then reset the interface as much as we can */
367 if (!up) {
368 /* Only reset things if we had set them before */
369 if (iface->addr.s_addr != 0) {
370 delete_routes(iface, options->metric);
371 delete_address(iface);
372 }
373
374 run_script(options, iface->name, reason, NULL, old);
375 return 0;
376 }
377
378 /* This also changes netmask */
379 if (!(options->options & DHCPCD_INFORM) ||
380 !has_address(iface->name, &addr, &net)) {
381 logger(LOG_DEBUG, "adding IP address %s/%d",
382 inet_ntoa(addr), inet_ntocidr(net));
383 if (add_address(iface->name, &addr, &net, &brd) == -1 &&
384 errno != EEXIST)
385 {
386 logger(LOG_ERR, "add_address: %s", strerror(errno));
387 return -1;
388 }
389 }
390
391 /* Now delete the old address if different */
392 if (iface->addr.s_addr != addr.s_addr &&
393 iface->addr.s_addr != 0)
394 delete_address(iface);
395
396 #ifdef __linux__
397 /* On linux, we need to change the subnet route to have our metric. */
398 if (iface->addr.s_addr != lease->addr.s_addr &&
399 options->metric > 0 && net.s_addr != INADDR_BROADCAST)
400 {
401 dest.s_addr = addr.s_addr & net.s_addr;
402 gate.s_addr = 0;
403 add_route(iface->name, &dest, &net, &gate, options->metric);
404 del_route(iface->name, &dest, &net, &gate, 0);
405 }
406 #endif
407
408 configure_routes(iface, dhcp, options);
409 up = (iface->addr.s_addr != addr.s_addr ||
410 iface->net.s_addr != net.s_addr);
411 iface->addr.s_addr = addr.s_addr;
412 iface->net.s_addr = net.s_addr;
413
414 if (!lease->frominfo)
415 if (write_lease(iface, dhcp) == -1)
416 logger(LOG_ERR, "write_lease: %s", strerror(errno));
417
418 run_script(options, iface->name, reason, dhcp, old);
419 return 0;
420 }
421