1 /*
2 * Copyright 2008, The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 /* Utilities for managing the dhcpcd DHCP client daemon */
18
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <unistd.h>
23 #include <arpa/inet.h>
24 #include <netinet/in.h>
25
26 #include <cutils/properties.h>
27
28 static const char DAEMON_NAME[] = "dhcpcd";
29 static const char DAEMON_PROP_NAME[] = "init.svc.dhcpcd";
30 static const char HOSTNAME_PROP_NAME[] = "net.hostname";
31 static const char DHCP_PROP_NAME_PREFIX[] = "dhcp";
32 static const char DHCP_CONFIG_PATH[] = "/system/etc/dhcpcd/dhcpcd.conf";
33 static const int NAP_TIME = 200; /* wait for 200ms at a time */
34 /* when polling for property values */
35 static const char DAEMON_NAME_RENEW[] = "iprenew";
36 static char errmsg[100];
37 /* interface length for dhcpcd daemon start (dhcpcd_<interface> as defined in init.rc file)
38 * or for filling up system properties dhcpcd.<interface>.ipaddress, dhcpcd.<interface>.dns1
39 * and other properties on a successful bind
40 */
41 #define MAX_INTERFACE_LENGTH 25
42
43 /*
44 * P2p interface names increase sequentially p2p-p2p0-1, p2p-p2p0-2.. after
45 * group formation. This does not work well with system properties which can quickly
46 * exhaust or for specifiying a dhcp start target in init which requires
47 * interface to be pre-defined in init.rc file.
48 *
49 * This function returns a common string p2p for all p2p interfaces.
50 */
get_p2p_interface_replacement(const char * interface,char * p2p_interface)51 void get_p2p_interface_replacement(const char *interface, char *p2p_interface) {
52 /* Use p2p for any interface starting with p2p. */
53 if (strncmp(interface, "p2p",3) == 0) {
54 strncpy(p2p_interface, "p2p", MAX_INTERFACE_LENGTH);
55 } else {
56 strncpy(p2p_interface, interface, MAX_INTERFACE_LENGTH);
57 }
58 }
59
60 /*
61 * Wait for a system property to be assigned a specified value.
62 * If desired_value is NULL, then just wait for the property to
63 * be created with any value. maxwait is the maximum amount of
64 * time in seconds to wait before giving up.
65 */
wait_for_property(const char * name,const char * desired_value,int maxwait)66 static int wait_for_property(const char *name, const char *desired_value, int maxwait)
67 {
68 char value[PROPERTY_VALUE_MAX] = {'\0'};
69 int maxnaps = (maxwait * 1000) / NAP_TIME;
70
71 if (maxnaps < 1) {
72 maxnaps = 1;
73 }
74
75 while (maxnaps-- > 0) {
76 usleep(NAP_TIME * 1000);
77 if (property_get(name, value, NULL)) {
78 if (desired_value == NULL ||
79 strcmp(value, desired_value) == 0) {
80 return 0;
81 }
82 }
83 }
84 return -1; /* failure */
85 }
86
fill_ip_info(const char * interface,char * ipaddr,char * gateway,uint32_t * prefixLength,char * dns[],char * server,uint32_t * lease,char * vendorInfo,char * domain,char * mtu)87 static int fill_ip_info(const char *interface,
88 char *ipaddr,
89 char *gateway,
90 uint32_t *prefixLength,
91 char *dns[],
92 char *server,
93 uint32_t *lease,
94 char *vendorInfo,
95 char *domain,
96 char *mtu)
97 {
98 char prop_name[PROPERTY_KEY_MAX];
99 char prop_value[PROPERTY_VALUE_MAX];
100 /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
101 char p2p_interface[MAX_INTERFACE_LENGTH];
102 int x;
103
104 get_p2p_interface_replacement(interface, p2p_interface);
105
106 snprintf(prop_name, sizeof(prop_name), "%s.%s.ipaddress", DHCP_PROP_NAME_PREFIX, p2p_interface);
107 property_get(prop_name, ipaddr, NULL);
108
109 snprintf(prop_name, sizeof(prop_name), "%s.%s.gateway", DHCP_PROP_NAME_PREFIX, p2p_interface);
110 property_get(prop_name, gateway, NULL);
111
112 snprintf(prop_name, sizeof(prop_name), "%s.%s.server", DHCP_PROP_NAME_PREFIX, p2p_interface);
113 property_get(prop_name, server, NULL);
114
115 //TODO: Handle IPv6 when we change system property usage
116 if (gateway[0] == '\0' || strncmp(gateway, "0.0.0.0", 7) == 0) {
117 //DHCP server is our best bet as gateway
118 strncpy(gateway, server, PROPERTY_VALUE_MAX);
119 }
120
121 snprintf(prop_name, sizeof(prop_name), "%s.%s.mask", DHCP_PROP_NAME_PREFIX, p2p_interface);
122 if (property_get(prop_name, prop_value, NULL)) {
123 int p;
124 // this conversion is v4 only, but this dhcp client is v4 only anyway
125 in_addr_t mask = ntohl(inet_addr(prop_value));
126 // Check netmask is a valid IP address. ntohl gives NONE response (all 1's) for
127 // non 255.255.255.255 inputs. if we get that value check if it is legit..
128 if (mask == INADDR_NONE && strcmp(prop_value, "255.255.255.255") != 0) {
129 snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value);
130 return -1;
131 }
132 for (p = 0; p < 32; p++) {
133 if (mask == 0) break;
134 // check for non-contiguous netmask, e.g., 255.254.255.0
135 if ((mask & 0x80000000) == 0) {
136 snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value);
137 return -1;
138 }
139 mask = mask << 1;
140 }
141 *prefixLength = p;
142 }
143
144 for (x=0; dns[x] != NULL; x++) {
145 snprintf(prop_name, sizeof(prop_name), "%s.%s.dns%d", DHCP_PROP_NAME_PREFIX, p2p_interface, x+1);
146 property_get(prop_name, dns[x], NULL);
147 }
148
149 snprintf(prop_name, sizeof(prop_name), "%s.%s.leasetime", DHCP_PROP_NAME_PREFIX, p2p_interface);
150 if (property_get(prop_name, prop_value, NULL)) {
151 *lease = atol(prop_value);
152 }
153
154 snprintf(prop_name, sizeof(prop_name), "%s.%s.vendorInfo", DHCP_PROP_NAME_PREFIX,
155 p2p_interface);
156 property_get(prop_name, vendorInfo, NULL);
157
158 snprintf(prop_name, sizeof(prop_name), "%s.%s.domain", DHCP_PROP_NAME_PREFIX,
159 p2p_interface);
160 property_get(prop_name, domain, NULL);
161
162 snprintf(prop_name, sizeof(prop_name), "%s.%s.mtu", DHCP_PROP_NAME_PREFIX,
163 p2p_interface);
164 property_get(prop_name, mtu, NULL);
165
166 return 0;
167 }
168
ipaddr_to_string(in_addr_t addr)169 static const char *ipaddr_to_string(in_addr_t addr)
170 {
171 struct in_addr in_addr;
172
173 in_addr.s_addr = addr;
174 return inet_ntoa(in_addr);
175 }
176
177 /*
178 * Start the dhcp client daemon, and wait for it to finish
179 * configuring the interface.
180 *
181 * The device init.rc file needs a corresponding entry for this work.
182 *
183 * Example:
184 * service dhcpcd_<interface> /system/bin/dhcpcd -ABKL -f dhcpcd.conf
185 */
dhcp_do_request(const char * interface,char * ipaddr,char * gateway,uint32_t * prefixLength,char * dns[],char * server,uint32_t * lease,char * vendorInfo,char * domain,char * mtu)186 int dhcp_do_request(const char *interface,
187 char *ipaddr,
188 char *gateway,
189 uint32_t *prefixLength,
190 char *dns[],
191 char *server,
192 uint32_t *lease,
193 char *vendorInfo,
194 char *domain,
195 char *mtu)
196 {
197 char result_prop_name[PROPERTY_KEY_MAX];
198 char daemon_prop_name[PROPERTY_KEY_MAX];
199 char prop_value[PROPERTY_VALUE_MAX] = {'\0'};
200 char daemon_cmd[PROPERTY_VALUE_MAX * 2 + sizeof(DHCP_CONFIG_PATH)];
201 const char *ctrl_prop = "ctl.start";
202 const char *desired_status = "running";
203 /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
204 char p2p_interface[MAX_INTERFACE_LENGTH];
205
206 get_p2p_interface_replacement(interface, p2p_interface);
207
208 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
209 DHCP_PROP_NAME_PREFIX,
210 p2p_interface);
211
212 snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
213 DAEMON_PROP_NAME,
214 p2p_interface);
215
216 /* Erase any previous setting of the dhcp result property */
217 property_set(result_prop_name, "");
218
219 /* Start the daemon and wait until it's ready */
220 if (property_get(HOSTNAME_PROP_NAME, prop_value, NULL) && (prop_value[0] != '\0'))
221 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:-f %s -h %s %s", DAEMON_NAME,
222 p2p_interface, DHCP_CONFIG_PATH, prop_value, interface);
223 else
224 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:-f %s %s", DAEMON_NAME,
225 p2p_interface, DHCP_CONFIG_PATH, interface);
226 memset(prop_value, '\0', PROPERTY_VALUE_MAX);
227 property_set(ctrl_prop, daemon_cmd);
228 if (wait_for_property(daemon_prop_name, desired_status, 10) < 0) {
229 snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for dhcpcd to start");
230 return -1;
231 }
232
233 /* Wait for the daemon to return a result */
234 if (wait_for_property(result_prop_name, NULL, 30) < 0) {
235 snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP to finish");
236 return -1;
237 }
238
239 if (!property_get(result_prop_name, prop_value, NULL)) {
240 /* shouldn't ever happen, given the success of wait_for_property() */
241 snprintf(errmsg, sizeof(errmsg), "%s", "DHCP result property was not set");
242 return -1;
243 }
244 if (strcmp(prop_value, "ok") == 0) {
245 char dns_prop_name[PROPERTY_KEY_MAX];
246 if (fill_ip_info(interface, ipaddr, gateway, prefixLength, dns,
247 server, lease, vendorInfo, domain, mtu) == -1) {
248 return -1;
249 }
250 return 0;
251 } else {
252 snprintf(errmsg, sizeof(errmsg), "DHCP result was %s", prop_value);
253 return -1;
254 }
255 }
256
257 /**
258 * Stop the DHCP client daemon.
259 */
dhcp_stop(const char * interface)260 int dhcp_stop(const char *interface)
261 {
262 char result_prop_name[PROPERTY_KEY_MAX];
263 char daemon_prop_name[PROPERTY_KEY_MAX];
264 char daemon_cmd[PROPERTY_VALUE_MAX * 2];
265 const char *ctrl_prop = "ctl.stop";
266 const char *desired_status = "stopped";
267
268 char p2p_interface[MAX_INTERFACE_LENGTH];
269
270 get_p2p_interface_replacement(interface, p2p_interface);
271
272 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
273 DHCP_PROP_NAME_PREFIX,
274 p2p_interface);
275
276 snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
277 DAEMON_PROP_NAME,
278 p2p_interface);
279
280 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface);
281
282 /* Stop the daemon and wait until it's reported to be stopped */
283 property_set(ctrl_prop, daemon_cmd);
284 if (wait_for_property(daemon_prop_name, desired_status, 5) < 0) {
285 return -1;
286 }
287 property_set(result_prop_name, "failed");
288 return 0;
289 }
290
291 /**
292 * Release the current DHCP client lease.
293 */
dhcp_release_lease(const char * interface)294 int dhcp_release_lease(const char *interface)
295 {
296 char daemon_prop_name[PROPERTY_KEY_MAX];
297 char daemon_cmd[PROPERTY_VALUE_MAX * 2];
298 const char *ctrl_prop = "ctl.stop";
299 const char *desired_status = "stopped";
300
301 char p2p_interface[MAX_INTERFACE_LENGTH];
302
303 get_p2p_interface_replacement(interface, p2p_interface);
304
305 snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
306 DAEMON_PROP_NAME,
307 p2p_interface);
308
309 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface);
310
311 /* Stop the daemon and wait until it's reported to be stopped */
312 property_set(ctrl_prop, daemon_cmd);
313 if (wait_for_property(daemon_prop_name, desired_status, 5) < 0) {
314 return -1;
315 }
316 return 0;
317 }
318
dhcp_get_errmsg()319 char *dhcp_get_errmsg() {
320 return errmsg;
321 }
322
323 /**
324 * The device init.rc file needs a corresponding entry.
325 *
326 * Example:
327 * service iprenew_<interface> /system/bin/dhcpcd -n
328 *
329 */
dhcp_do_request_renew(const char * interface,char * ipaddr,char * gateway,uint32_t * prefixLength,char * dns[],char * server,uint32_t * lease,char * vendorInfo,char * domain,char * mtu)330 int dhcp_do_request_renew(const char *interface,
331 char *ipaddr,
332 char *gateway,
333 uint32_t *prefixLength,
334 char *dns[],
335 char *server,
336 uint32_t *lease,
337 char *vendorInfo,
338 char *domain,
339 char *mtu)
340 {
341 char result_prop_name[PROPERTY_KEY_MAX];
342 char prop_value[PROPERTY_VALUE_MAX] = {'\0'};
343 char daemon_cmd[PROPERTY_VALUE_MAX * 2];
344 const char *ctrl_prop = "ctl.start";
345
346 char p2p_interface[MAX_INTERFACE_LENGTH];
347
348 get_p2p_interface_replacement(interface, p2p_interface);
349
350 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
351 DHCP_PROP_NAME_PREFIX,
352 p2p_interface);
353
354 /* Erase any previous setting of the dhcp result property */
355 property_set(result_prop_name, "");
356
357 /* Start the renew daemon and wait until it's ready */
358 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:%s", DAEMON_NAME_RENEW,
359 p2p_interface, interface);
360 memset(prop_value, '\0', PROPERTY_VALUE_MAX);
361 property_set(ctrl_prop, daemon_cmd);
362
363 /* Wait for the daemon to return a result */
364 if (wait_for_property(result_prop_name, NULL, 30) < 0) {
365 snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP Renew to finish");
366 return -1;
367 }
368
369 if (!property_get(result_prop_name, prop_value, NULL)) {
370 /* shouldn't ever happen, given the success of wait_for_property() */
371 snprintf(errmsg, sizeof(errmsg), "%s", "DHCP Renew result property was not set");
372 return -1;
373 }
374 if (strcmp(prop_value, "ok") == 0) {
375 return fill_ip_info(interface, ipaddr, gateway, prefixLength, dns,
376 server, lease, vendorInfo, domain, mtu);
377 } else {
378 snprintf(errmsg, sizeof(errmsg), "DHCP Renew result was %s", prop_value);
379 return -1;
380 }
381 }
382