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] = "\0";
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 if (property_get(name, value, NULL)) {
77 if (desired_value == NULL ||
78 strcmp(value, desired_value) == 0) {
79 return 0;
80 }
81 }
82 if (maxnaps >= 0) {
83 usleep(NAP_TIME * 1000);
84 }
85 }
86 return -1; /* failure */
87 }
88
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)89 static int fill_ip_info(const char *interface,
90 char *ipaddr,
91 char *gateway,
92 uint32_t *prefixLength,
93 char *dns[],
94 char *server,
95 uint32_t *lease,
96 char *vendorInfo,
97 char *domain,
98 char *mtu)
99 {
100 char prop_name[PROPERTY_KEY_MAX];
101 char prop_value[PROPERTY_VALUE_MAX];
102 /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
103 char p2p_interface[MAX_INTERFACE_LENGTH];
104 int x;
105
106 get_p2p_interface_replacement(interface, p2p_interface);
107
108 snprintf(prop_name, sizeof(prop_name), "%s.%s.ipaddress", DHCP_PROP_NAME_PREFIX, p2p_interface);
109 property_get(prop_name, ipaddr, NULL);
110
111 snprintf(prop_name, sizeof(prop_name), "%s.%s.gateway", DHCP_PROP_NAME_PREFIX, p2p_interface);
112 property_get(prop_name, gateway, NULL);
113
114 snprintf(prop_name, sizeof(prop_name), "%s.%s.server", DHCP_PROP_NAME_PREFIX, p2p_interface);
115 property_get(prop_name, server, NULL);
116
117 //TODO: Handle IPv6 when we change system property usage
118 if (gateway[0] == '\0' || strncmp(gateway, "0.0.0.0", 7) == 0) {
119 //DHCP server is our best bet as gateway
120 strncpy(gateway, server, PROPERTY_VALUE_MAX);
121 }
122
123 snprintf(prop_name, sizeof(prop_name), "%s.%s.mask", DHCP_PROP_NAME_PREFIX, p2p_interface);
124 if (property_get(prop_name, prop_value, NULL)) {
125 int p;
126 // this conversion is v4 only, but this dhcp client is v4 only anyway
127 in_addr_t mask = ntohl(inet_addr(prop_value));
128 // Check netmask is a valid IP address. ntohl gives NONE response (all 1's) for
129 // non 255.255.255.255 inputs. if we get that value check if it is legit..
130 if (mask == INADDR_NONE && strcmp(prop_value, "255.255.255.255") != 0) {
131 snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value);
132 return -1;
133 }
134 for (p = 0; p < 32; p++) {
135 if (mask == 0) break;
136 // check for non-contiguous netmask, e.g., 255.254.255.0
137 if ((mask & 0x80000000) == 0) {
138 snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value);
139 return -1;
140 }
141 mask = mask << 1;
142 }
143 *prefixLength = p;
144 }
145
146 for (x=0; dns[x] != NULL; x++) {
147 snprintf(prop_name, sizeof(prop_name), "%s.%s.dns%d", DHCP_PROP_NAME_PREFIX, p2p_interface, x+1);
148 property_get(prop_name, dns[x], NULL);
149 }
150
151 snprintf(prop_name, sizeof(prop_name), "%s.%s.leasetime", DHCP_PROP_NAME_PREFIX, p2p_interface);
152 if (property_get(prop_name, prop_value, NULL)) {
153 *lease = atol(prop_value);
154 }
155
156 snprintf(prop_name, sizeof(prop_name), "%s.%s.vendorInfo", DHCP_PROP_NAME_PREFIX,
157 p2p_interface);
158 property_get(prop_name, vendorInfo, NULL);
159
160 snprintf(prop_name, sizeof(prop_name), "%s.%s.domain", DHCP_PROP_NAME_PREFIX,
161 p2p_interface);
162 property_get(prop_name, domain, NULL);
163
164 snprintf(prop_name, sizeof(prop_name), "%s.%s.mtu", DHCP_PROP_NAME_PREFIX,
165 p2p_interface);
166 property_get(prop_name, mtu, NULL);
167
168 return 0;
169 }
170
171 /*
172 * Get any available DHCP results.
173 */
dhcp_get_results(const char * interface,char * ipaddr,char * gateway,uint32_t * prefixLength,char * dns[],char * server,uint32_t * lease,char * vendorInfo,char * domain,char * mtu)174 int dhcp_get_results(const char *interface,
175 char *ipaddr,
176 char *gateway,
177 uint32_t *prefixLength,
178 char *dns[],
179 char *server,
180 uint32_t *lease,
181 char *vendorInfo,
182 char *domain,
183 char *mtu)
184 {
185 char result_prop_name[PROPERTY_KEY_MAX];
186 char prop_value[PROPERTY_VALUE_MAX];
187
188 /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
189 char p2p_interface[MAX_INTERFACE_LENGTH];
190 get_p2p_interface_replacement(interface, p2p_interface);
191 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
192 DHCP_PROP_NAME_PREFIX,
193 p2p_interface);
194
195 memset(prop_value, '\0', PROPERTY_VALUE_MAX);
196 if (!property_get(result_prop_name, prop_value, NULL)) {
197 snprintf(errmsg, sizeof(errmsg), "%s", "DHCP result property was not set");
198 return -1;
199 }
200 if (strcmp(prop_value, "ok") == 0) {
201 if (fill_ip_info(interface, ipaddr, gateway, prefixLength, dns,
202 server, lease, vendorInfo, domain, mtu) == -1) {
203 return -1;
204 }
205 return 0;
206 } else {
207 snprintf(errmsg, sizeof(errmsg), "DHCP result was %s", prop_value);
208 return -1;
209 }
210 }
211
212 /*
213 * Start the dhcp client daemon, and wait for it to finish
214 * configuring the interface.
215 *
216 * The device init.rc file needs a corresponding entry for this work.
217 *
218 * Example:
219 * service dhcpcd_<interface> /system/bin/dhcpcd -ABKL -f dhcpcd.conf
220 */
dhcp_start(const char * interface)221 int dhcp_start(const char *interface)
222 {
223 char result_prop_name[PROPERTY_KEY_MAX];
224 char daemon_prop_name[PROPERTY_KEY_MAX];
225 char prop_value[PROPERTY_VALUE_MAX] = {'\0'};
226 char daemon_cmd[PROPERTY_VALUE_MAX * 2 + sizeof(DHCP_CONFIG_PATH)];
227 const char *ctrl_prop = "ctl.start";
228 const char *desired_status = "running";
229 /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
230 char p2p_interface[MAX_INTERFACE_LENGTH];
231
232 get_p2p_interface_replacement(interface, p2p_interface);
233
234 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
235 DHCP_PROP_NAME_PREFIX,
236 p2p_interface);
237
238 snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
239 DAEMON_PROP_NAME,
240 p2p_interface);
241
242 /* Erase any previous setting of the dhcp result property */
243 property_set(result_prop_name, "");
244
245 /* Start the daemon and wait until it's ready */
246 if (property_get(HOSTNAME_PROP_NAME, prop_value, NULL) && (prop_value[0] != '\0'))
247 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:-f %s -h %s %s", DAEMON_NAME,
248 p2p_interface, DHCP_CONFIG_PATH, prop_value, interface);
249 else
250 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:-f %s %s", DAEMON_NAME,
251 p2p_interface, DHCP_CONFIG_PATH, interface);
252 memset(prop_value, '\0', PROPERTY_VALUE_MAX);
253 property_set(ctrl_prop, daemon_cmd);
254 if (wait_for_property(daemon_prop_name, desired_status, 10) < 0) {
255 snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for dhcpcd to start");
256 return -1;
257 }
258
259 /* Wait for the daemon to return a result */
260 if (wait_for_property(result_prop_name, NULL, 30) < 0) {
261 snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP to finish");
262 return -1;
263 }
264
265 return 0;
266 }
267
268 /**
269 * Stop the DHCP client daemon.
270 */
dhcp_stop(const char * interface)271 int dhcp_stop(const char *interface)
272 {
273 char result_prop_name[PROPERTY_KEY_MAX];
274 char daemon_prop_name[PROPERTY_KEY_MAX];
275 char daemon_cmd[PROPERTY_VALUE_MAX * 2];
276 const char *ctrl_prop = "ctl.stop";
277 const char *desired_status = "stopped";
278
279 char p2p_interface[MAX_INTERFACE_LENGTH];
280
281 get_p2p_interface_replacement(interface, p2p_interface);
282
283 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
284 DHCP_PROP_NAME_PREFIX,
285 p2p_interface);
286
287 snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
288 DAEMON_PROP_NAME,
289 p2p_interface);
290
291 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface);
292
293 /* Stop the daemon and wait until it's reported to be stopped */
294 property_set(ctrl_prop, daemon_cmd);
295 if (wait_for_property(daemon_prop_name, desired_status, 5) < 0) {
296 return -1;
297 }
298 property_set(result_prop_name, "failed");
299 return 0;
300 }
301
302 /**
303 * Release the current DHCP client lease.
304 */
dhcp_release_lease(const char * interface)305 int dhcp_release_lease(const char *interface)
306 {
307 char daemon_prop_name[PROPERTY_KEY_MAX];
308 char daemon_cmd[PROPERTY_VALUE_MAX * 2];
309 const char *ctrl_prop = "ctl.stop";
310 const char *desired_status = "stopped";
311
312 char p2p_interface[MAX_INTERFACE_LENGTH];
313
314 get_p2p_interface_replacement(interface, p2p_interface);
315
316 snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
317 DAEMON_PROP_NAME,
318 p2p_interface);
319
320 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface);
321
322 /* Stop the daemon and wait until it's reported to be stopped */
323 property_set(ctrl_prop, daemon_cmd);
324 if (wait_for_property(daemon_prop_name, desired_status, 5) < 0) {
325 return -1;
326 }
327 return 0;
328 }
329
dhcp_get_errmsg()330 char *dhcp_get_errmsg() {
331 return errmsg;
332 }
333
334 /**
335 * The device init.rc file needs a corresponding entry.
336 *
337 * Example:
338 * service iprenew_<interface> /system/bin/dhcpcd -n
339 *
340 */
dhcp_start_renew(const char * interface)341 int dhcp_start_renew(const char *interface)
342 {
343 char result_prop_name[PROPERTY_KEY_MAX];
344 char prop_value[PROPERTY_VALUE_MAX] = {'\0'};
345 char daemon_cmd[PROPERTY_VALUE_MAX * 2];
346 const char *ctrl_prop = "ctl.start";
347
348 char p2p_interface[MAX_INTERFACE_LENGTH];
349
350 get_p2p_interface_replacement(interface, p2p_interface);
351
352 snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
353 DHCP_PROP_NAME_PREFIX,
354 p2p_interface);
355
356 /* Erase any previous setting of the dhcp result property */
357 property_set(result_prop_name, "");
358
359 /* Start the renew daemon and wait until it's ready */
360 snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:%s", DAEMON_NAME_RENEW,
361 p2p_interface, interface);
362 memset(prop_value, '\0', PROPERTY_VALUE_MAX);
363 property_set(ctrl_prop, daemon_cmd);
364
365 /* Wait for the daemon to return a result */
366 if (wait_for_property(result_prop_name, NULL, 30) < 0) {
367 snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP Renew to finish");
368 return -1;
369 }
370
371 return 0;
372 }
373