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 mDhcpcdPid = 0;
42 }
43
~TetherController()44 TetherController::~TetherController() {
45 InterfaceCollection::iterator it;
46
47 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
48 free(*it);
49 }
50 mInterfaces->clear();
51
52 mDnsForwarders->clear();
53 }
54
setIpFwdEnabled(bool enable)55 int TetherController::setIpFwdEnabled(bool enable) {
56
57 ALOGD("Setting IP forward enable = %d", enable);
58
59 // In BP tools mode, do not disable IP forwarding
60 char bootmode[PROPERTY_VALUE_MAX] = {0};
61 property_get("ro.bootmode", bootmode, "unknown");
62 if ((enable == false) && (0 == strcmp("bp-tools", bootmode))) {
63 return 0;
64 }
65
66 int fd = open("/proc/sys/net/ipv4/ip_forward", O_WRONLY);
67 if (fd < 0) {
68 ALOGE("Failed to open ip_forward (%s)", strerror(errno));
69 return -1;
70 }
71
72 if (write(fd, (enable ? "1" : "0"), 1) != 1) {
73 ALOGE("Failed to write ip_forward (%s)", strerror(errno));
74 close(fd);
75 return -1;
76 }
77 close(fd);
78 return 0;
79 }
80
getIpFwdEnabled()81 bool TetherController::getIpFwdEnabled() {
82 int fd = open("/proc/sys/net/ipv4/ip_forward", O_RDONLY);
83
84 if (fd < 0) {
85 ALOGE("Failed to open ip_forward (%s)", strerror(errno));
86 return false;
87 }
88
89 char enabled;
90 if (read(fd, &enabled, 1) != 1) {
91 ALOGE("Failed to read ip_forward (%s)", strerror(errno));
92 close(fd);
93 return -1;
94 }
95
96 close(fd);
97 return (enabled == '1' ? true : false);
98 }
99
startTethering(int num_addrs,struct in_addr * addrs)100 int TetherController::startTethering(int num_addrs, struct in_addr* addrs) {
101 if (mDaemonPid != 0) {
102 ALOGE("Tethering already started");
103 errno = EBUSY;
104 return -1;
105 }
106
107 ALOGD("Starting tethering services");
108
109 pid_t pid;
110 int pipefd[2];
111
112 if (pipe(pipefd) < 0) {
113 ALOGE("pipe failed (%s)", strerror(errno));
114 return -1;
115 }
116
117 /*
118 * TODO: Create a monitoring thread to handle and restart
119 * the daemon if it exits prematurely
120 */
121 if ((pid = fork()) < 0) {
122 ALOGE("fork failed (%s)", strerror(errno));
123 close(pipefd[0]);
124 close(pipefd[1]);
125 return -1;
126 }
127
128 if (!pid) {
129 close(pipefd[1]);
130 if (pipefd[0] != STDIN_FILENO) {
131 if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) {
132 ALOGE("dup2 failed (%s)", strerror(errno));
133 return -1;
134 }
135 close(pipefd[0]);
136 }
137
138 int num_processed_args = 7 + (num_addrs/2) + 1; // 1 null for termination
139 char **args = (char **)malloc(sizeof(char *) * num_processed_args);
140 args[num_processed_args - 1] = NULL;
141 args[0] = (char *)"/system/bin/dnsmasq";
142 args[1] = (char *)"--keep-in-foreground";
143 args[2] = (char *)"--no-resolv";
144 args[3] = (char *)"--no-poll";
145 // TODO: pipe through metered status from ConnService
146 args[4] = (char *)"--dhcp-option-force=43,ANDROID_METERED";
147 args[5] = (char *)"--pid-file";
148 args[6] = (char *)"";
149
150 int nextArg = 7;
151 for (int addrIndex=0; addrIndex < num_addrs;) {
152 char *start = strdup(inet_ntoa(addrs[addrIndex++]));
153 char *end = strdup(inet_ntoa(addrs[addrIndex++]));
154 asprintf(&(args[nextArg++]),"--dhcp-range=%s,%s,1h", start, end);
155 }
156
157 if (execv(args[0], args)) {
158 ALOGE("execl failed (%s)", strerror(errno));
159 }
160 ALOGE("Should never get here!");
161 free(args);
162 return 0;
163 } else {
164 close(pipefd[0]);
165 mDaemonPid = pid;
166 mDaemonFd = pipefd[1];
167 ALOGD("Tethering services running");
168 }
169
170 return 0;
171 }
172
stopTethering()173 int TetherController::stopTethering() {
174
175 if (mDaemonPid == 0) {
176 ALOGE("Tethering already stopped");
177 return 0;
178 }
179
180 ALOGD("Stopping tethering services");
181
182 kill(mDaemonPid, SIGTERM);
183 waitpid(mDaemonPid, NULL, 0);
184 mDaemonPid = 0;
185 close(mDaemonFd);
186 mDaemonFd = -1;
187 ALOGD("Tethering services stopped");
188 return 0;
189 }
190
191 // TODO(BT) remove
startReverseTethering(const char * iface)192 int TetherController::startReverseTethering(const char* iface) {
193 if (mDhcpcdPid != 0) {
194 ALOGE("Reverse tethering already started");
195 errno = EBUSY;
196 return -1;
197 }
198
199 ALOGD("TetherController::startReverseTethering, Starting reverse tethering");
200
201 /*
202 * TODO: Create a monitoring thread to handle and restart
203 * the daemon if it exits prematurely
204 */
205 //cleanup the dhcp result
206 char dhcp_result_name[64];
207 snprintf(dhcp_result_name, sizeof(dhcp_result_name) - 1, "dhcp.%s.result", iface);
208 property_set(dhcp_result_name, "");
209
210 pid_t pid;
211 if ((pid = fork()) < 0) {
212 ALOGE("fork failed (%s)", strerror(errno));
213 return -1;
214 }
215
216 if (!pid) {
217
218 char *args[10];
219 int argc = 0;
220 args[argc++] = "/system/bin/dhcpcd";
221 char host_name[128];
222 if (property_get("net.hostname", host_name, NULL) && (host_name[0] != '\0'))
223 {
224 args[argc++] = "-h";
225 args[argc++] = host_name;
226 }
227 args[argc++] = (char*)iface;
228 args[argc] = NULL;
229 if (execv(args[0], args)) {
230 ALOGE("startReverseTethering, execv failed (%s)", strerror(errno));
231 }
232 ALOGE("startReverseTethering, Should never get here!");
233 // TODO(BT) inform parent of the failure.
234 // Parent process need wait for child to report error status
235 // before it set mDhcpcdPid and return 0.
236 exit(-1);
237 } else {
238 mDhcpcdPid = pid;
239 ALOGD("Reverse Tethering running, pid:%d", pid);
240 }
241 return 0;
242 }
243
244 // TODO(BT) remove
stopReverseTethering()245 int TetherController::stopReverseTethering() {
246
247 if (mDhcpcdPid == 0) {
248 ALOGE("Tethering already stopped");
249 return 0;
250 }
251
252 ALOGD("Stopping tethering services");
253
254 kill(mDhcpcdPid, SIGTERM);
255 waitpid(mDhcpcdPid, NULL, 0);
256 mDhcpcdPid = 0;
257 ALOGD("Tethering services stopped");
258 return 0;
259 }
isTetheringStarted()260 bool TetherController::isTetheringStarted() {
261 return (mDaemonPid == 0 ? false : true);
262 }
263
264 #define MAX_CMD_SIZE 1024
265
setDnsForwarders(char ** servers,int numServers)266 int TetherController::setDnsForwarders(char **servers, int numServers) {
267 int i;
268 char daemonCmd[MAX_CMD_SIZE];
269
270 strcpy(daemonCmd, "update_dns");
271 int cmdLen = strlen(daemonCmd);
272
273 mDnsForwarders->clear();
274 for (i = 0; i < numServers; i++) {
275 ALOGD("setDnsForwarders(%d = '%s')", i, servers[i]);
276
277 struct in_addr a;
278
279 if (!inet_aton(servers[i], &a)) {
280 ALOGE("Failed to parse DNS server '%s'", servers[i]);
281 mDnsForwarders->clear();
282 return -1;
283 }
284
285 cmdLen += (strlen(servers[i]) + 1);
286 if (cmdLen + 1 >= MAX_CMD_SIZE) {
287 ALOGD("Too many DNS servers listed");
288 break;
289 }
290
291 strcat(daemonCmd, ":");
292 strcat(daemonCmd, servers[i]);
293 mDnsForwarders->push_back(a);
294 }
295
296 if (mDaemonFd != -1) {
297 ALOGD("Sending update msg to dnsmasq [%s]", daemonCmd);
298 if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) {
299 ALOGE("Failed to send update command to dnsmasq (%s)", strerror(errno));
300 mDnsForwarders->clear();
301 return -1;
302 }
303 }
304 return 0;
305 }
306
getDnsForwarders()307 NetAddressCollection *TetherController::getDnsForwarders() {
308 return mDnsForwarders;
309 }
310
tetherInterface(const char * interface)311 int TetherController::tetherInterface(const char *interface) {
312 mInterfaces->push_back(strdup(interface));
313 return 0;
314 }
315
untetherInterface(const char * interface)316 int TetherController::untetherInterface(const char *interface) {
317 InterfaceCollection::iterator it;
318
319 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
320 if (!strcmp(interface, *it)) {
321 free(*it);
322 mInterfaces->erase(it);
323 return 0;
324 }
325 }
326 errno = ENOENT;
327 return -1;
328 }
329
getTetheredInterfaceList()330 InterfaceCollection *TetherController::getTetheredInterfaceList() {
331 return mInterfaces;
332 }
333