1 /*
2 * Copyright (C) 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 #include <stdlib.h>
18 #include <errno.h>
19 #include <fcntl.h>
20 #include <string.h>
21
22 #include <sys/socket.h>
23 #include <sys/stat.h>
24 #include <sys/types.h>
25 #include <sys/wait.h>
26
27 #include <netinet/in.h>
28 #include <arpa/inet.h>
29
30 #define LOG_TAG "TetherController"
31 #include <cutils/log.h>
32 #include <cutils/properties.h>
33
34 #include "TetherController.h"
35
TetherController()36 TetherController::TetherController() {
37 mInterfaces = new InterfaceCollection();
38 mDnsForwarders = new NetAddressCollection();
39 mDaemonFd = -1;
40 mDaemonPid = 0;
41 }
42
~TetherController()43 TetherController::~TetherController() {
44 InterfaceCollection::iterator it;
45
46 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
47 free(*it);
48 }
49 mInterfaces->clear();
50
51 mDnsForwarders->clear();
52 }
53
setIpFwdEnabled(bool enable)54 int TetherController::setIpFwdEnabled(bool enable) {
55
56 ALOGD("Setting IP forward enable = %d", enable);
57
58 // In BP tools mode, do not disable IP forwarding
59 char bootmode[PROPERTY_VALUE_MAX] = {0};
60 property_get("ro.bootmode", bootmode, "unknown");
61 if ((enable == false) && (0 == strcmp("bp-tools", bootmode))) {
62 return 0;
63 }
64
65 int fd = open("/proc/sys/net/ipv4/ip_forward", O_WRONLY);
66 if (fd < 0) {
67 ALOGE("Failed to open ip_forward (%s)", strerror(errno));
68 return -1;
69 }
70
71 if (write(fd, (enable ? "1" : "0"), 1) != 1) {
72 ALOGE("Failed to write ip_forward (%s)", strerror(errno));
73 close(fd);
74 return -1;
75 }
76 close(fd);
77 return 0;
78 }
79
getIpFwdEnabled()80 bool TetherController::getIpFwdEnabled() {
81 int fd = open("/proc/sys/net/ipv4/ip_forward", O_RDONLY);
82
83 if (fd < 0) {
84 ALOGE("Failed to open ip_forward (%s)", strerror(errno));
85 return false;
86 }
87
88 char enabled;
89 if (read(fd, &enabled, 1) != 1) {
90 ALOGE("Failed to read ip_forward (%s)", strerror(errno));
91 close(fd);
92 return -1;
93 }
94
95 close(fd);
96 return (enabled == '1' ? true : false);
97 }
98
startTethering(int num_addrs,struct in_addr * addrs)99 int TetherController::startTethering(int num_addrs, struct in_addr* addrs) {
100 if (mDaemonPid != 0) {
101 ALOGE("Tethering already started");
102 errno = EBUSY;
103 return -1;
104 }
105
106 ALOGD("Starting tethering services");
107
108 pid_t pid;
109 int pipefd[2];
110
111 if (pipe(pipefd) < 0) {
112 ALOGE("pipe failed (%s)", strerror(errno));
113 return -1;
114 }
115
116 /*
117 * TODO: Create a monitoring thread to handle and restart
118 * the daemon if it exits prematurely
119 */
120 if ((pid = fork()) < 0) {
121 ALOGE("fork failed (%s)", strerror(errno));
122 close(pipefd[0]);
123 close(pipefd[1]);
124 return -1;
125 }
126
127 if (!pid) {
128 close(pipefd[1]);
129 if (pipefd[0] != STDIN_FILENO) {
130 if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) {
131 ALOGE("dup2 failed (%s)", strerror(errno));
132 return -1;
133 }
134 close(pipefd[0]);
135 }
136
137 int num_processed_args = 7 + (num_addrs/2) + 1; // 1 null for termination
138 char **args = (char **)malloc(sizeof(char *) * num_processed_args);
139 args[num_processed_args - 1] = NULL;
140 args[0] = (char *)"/system/bin/dnsmasq";
141 args[1] = (char *)"--keep-in-foreground";
142 args[2] = (char *)"--no-resolv";
143 args[3] = (char *)"--no-poll";
144 // TODO: pipe through metered status from ConnService
145 args[4] = (char *)"--dhcp-option-force=43,ANDROID_METERED";
146 args[5] = (char *)"--pid-file";
147 args[6] = (char *)"";
148
149 int nextArg = 7;
150 for (int addrIndex=0; addrIndex < num_addrs;) {
151 char *start = strdup(inet_ntoa(addrs[addrIndex++]));
152 char *end = strdup(inet_ntoa(addrs[addrIndex++]));
153 asprintf(&(args[nextArg++]),"--dhcp-range=%s,%s,1h", start, end);
154 }
155
156 if (execv(args[0], args)) {
157 ALOGE("execl failed (%s)", strerror(errno));
158 }
159 ALOGE("Should never get here!");
160 _exit(-1);
161 } else {
162 close(pipefd[0]);
163 mDaemonPid = pid;
164 mDaemonFd = pipefd[1];
165 applyDnsInterfaces();
166 ALOGD("Tethering services running");
167 }
168
169 return 0;
170 }
171
stopTethering()172 int TetherController::stopTethering() {
173
174 if (mDaemonPid == 0) {
175 ALOGE("Tethering already stopped");
176 return 0;
177 }
178
179 ALOGD("Stopping tethering services");
180
181 kill(mDaemonPid, SIGTERM);
182 waitpid(mDaemonPid, NULL, 0);
183 mDaemonPid = 0;
184 close(mDaemonFd);
185 mDaemonFd = -1;
186 ALOGD("Tethering services stopped");
187 return 0;
188 }
189
isTetheringStarted()190 bool TetherController::isTetheringStarted() {
191 return (mDaemonPid == 0 ? false : true);
192 }
193
194 #define MAX_CMD_SIZE 1024
195
setDnsForwarders(char ** servers,int numServers)196 int TetherController::setDnsForwarders(char **servers, int numServers) {
197 int i;
198 char daemonCmd[MAX_CMD_SIZE];
199
200 strcpy(daemonCmd, "update_dns");
201 int cmdLen = strlen(daemonCmd);
202
203 mDnsForwarders->clear();
204 for (i = 0; i < numServers; i++) {
205 ALOGD("setDnsForwarders(%d = '%s')", i, servers[i]);
206
207 struct in_addr a;
208
209 if (!inet_aton(servers[i], &a)) {
210 ALOGE("Failed to parse DNS server '%s'", servers[i]);
211 mDnsForwarders->clear();
212 return -1;
213 }
214
215 cmdLen += (strlen(servers[i]) + 1);
216 if (cmdLen + 1 >= MAX_CMD_SIZE) {
217 ALOGD("Too many DNS servers listed");
218 break;
219 }
220
221 strcat(daemonCmd, ":");
222 strcat(daemonCmd, servers[i]);
223 mDnsForwarders->push_back(a);
224 }
225
226 if (mDaemonFd != -1) {
227 ALOGD("Sending update msg to dnsmasq [%s]", daemonCmd);
228 if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) {
229 ALOGE("Failed to send update command to dnsmasq (%s)", strerror(errno));
230 mDnsForwarders->clear();
231 return -1;
232 }
233 }
234 return 0;
235 }
236
getDnsForwarders()237 NetAddressCollection *TetherController::getDnsForwarders() {
238 return mDnsForwarders;
239 }
240
applyDnsInterfaces()241 int TetherController::applyDnsInterfaces() {
242 int i;
243 char daemonCmd[MAX_CMD_SIZE];
244
245 strcpy(daemonCmd, "update_ifaces");
246 int cmdLen = strlen(daemonCmd);
247 InterfaceCollection::iterator it;
248 bool haveInterfaces = false;
249
250 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
251 cmdLen += (strlen(*it) + 1);
252 if (cmdLen + 1 >= MAX_CMD_SIZE) {
253 ALOGD("Too many DNS ifaces listed");
254 break;
255 }
256
257 strcat(daemonCmd, ":");
258 strcat(daemonCmd, *it);
259 haveInterfaces = true;
260 }
261
262 if ((mDaemonFd != -1) && haveInterfaces) {
263 ALOGD("Sending update msg to dnsmasq [%s]", daemonCmd);
264 if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) {
265 ALOGE("Failed to send update command to dnsmasq (%s)", strerror(errno));
266 return -1;
267 }
268 }
269 return 0;
270 }
271
tetherInterface(const char * interface)272 int TetherController::tetherInterface(const char *interface) {
273 ALOGD("tetherInterface(%s)", interface);
274 mInterfaces->push_back(strdup(interface));
275
276 if (applyDnsInterfaces()) {
277 InterfaceCollection::iterator it;
278 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
279 if (!strcmp(interface, *it)) {
280 free(*it);
281 mInterfaces->erase(it);
282 break;
283 }
284 }
285 return -1;
286 } else {
287 return 0;
288 }
289 }
290
untetherInterface(const char * interface)291 int TetherController::untetherInterface(const char *interface) {
292 InterfaceCollection::iterator it;
293
294 ALOGD("untetherInterface(%s)", interface);
295
296 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
297 if (!strcmp(interface, *it)) {
298 free(*it);
299 mInterfaces->erase(it);
300
301 return applyDnsInterfaces();
302 }
303 }
304 errno = ENOENT;
305 return -1;
306 }
307
getTetheredInterfaceList()308 InterfaceCollection *TetherController::getTetheredInterfaceList() {
309 return mInterfaces;
310 }
311