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 "Fwmark.h"
35 #include "NetdConstants.h"
36 #include "Permission.h"
37 #include "TetherController.h"
38
TetherController()39 TetherController::TetherController() {
40 mInterfaces = new InterfaceCollection();
41 mDnsNetId = 0;
42 mDnsForwarders = new NetAddressCollection();
43 mDaemonFd = -1;
44 mDaemonPid = 0;
45 }
46
~TetherController()47 TetherController::~TetherController() {
48 InterfaceCollection::iterator it;
49
50 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
51 free(*it);
52 }
53 mInterfaces->clear();
54
55 mDnsForwarders->clear();
56 }
57
setIpFwdEnabled(bool enable)58 int TetherController::setIpFwdEnabled(bool enable) {
59
60 ALOGD("Setting IP forward enable = %d", enable);
61
62 // In BP tools mode, do not disable IP forwarding
63 char bootmode[PROPERTY_VALUE_MAX] = {0};
64 property_get("ro.bootmode", bootmode, "unknown");
65 if ((enable == false) && (0 == strcmp("bp-tools", bootmode))) {
66 return 0;
67 }
68
69 int fd = open("/proc/sys/net/ipv4/ip_forward", O_WRONLY);
70 if (fd < 0) {
71 ALOGE("Failed to open ip_forward (%s)", strerror(errno));
72 return -1;
73 }
74
75 if (write(fd, (enable ? "1" : "0"), 1) != 1) {
76 ALOGE("Failed to write ip_forward (%s)", strerror(errno));
77 close(fd);
78 return -1;
79 }
80 close(fd);
81 return 0;
82 }
83
getIpFwdEnabled()84 bool TetherController::getIpFwdEnabled() {
85 int fd = open("/proc/sys/net/ipv4/ip_forward", O_RDONLY);
86
87 if (fd < 0) {
88 ALOGE("Failed to open ip_forward (%s)", strerror(errno));
89 return false;
90 }
91
92 char enabled;
93 if (read(fd, &enabled, 1) != 1) {
94 ALOGE("Failed to read ip_forward (%s)", strerror(errno));
95 close(fd);
96 return -1;
97 }
98
99 close(fd);
100 return (enabled == '1' ? true : false);
101 }
102
103 #define TETHER_START_CONST_ARG 8
104
startTethering(int num_addrs,struct in_addr * addrs)105 int TetherController::startTethering(int num_addrs, struct in_addr* addrs) {
106 if (mDaemonPid != 0) {
107 ALOGE("Tethering already started");
108 errno = EBUSY;
109 return -1;
110 }
111
112 ALOGD("Starting tethering services");
113
114 pid_t pid;
115 int pipefd[2];
116
117 if (pipe(pipefd) < 0) {
118 ALOGE("pipe failed (%s)", strerror(errno));
119 return -1;
120 }
121
122 /*
123 * TODO: Create a monitoring thread to handle and restart
124 * the daemon if it exits prematurely
125 */
126 if ((pid = fork()) < 0) {
127 ALOGE("fork failed (%s)", strerror(errno));
128 close(pipefd[0]);
129 close(pipefd[1]);
130 return -1;
131 }
132
133 if (!pid) {
134 close(pipefd[1]);
135 if (pipefd[0] != STDIN_FILENO) {
136 if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) {
137 ALOGE("dup2 failed (%s)", strerror(errno));
138 return -1;
139 }
140 close(pipefd[0]);
141 }
142
143 int num_processed_args = TETHER_START_CONST_ARG + (num_addrs/2) + 1;
144 char **args = (char **)malloc(sizeof(char *) * num_processed_args);
145 args[num_processed_args - 1] = NULL;
146 args[0] = (char *)"/system/bin/dnsmasq";
147 args[1] = (char *)"--keep-in-foreground";
148 args[2] = (char *)"--no-resolv";
149 args[3] = (char *)"--no-poll";
150 args[4] = (char *)"--dhcp-authoritative";
151 // TODO: pipe through metered status from ConnService
152 args[5] = (char *)"--dhcp-option-force=43,ANDROID_METERED";
153 args[6] = (char *)"--pid-file";
154 args[7] = (char *)"";
155
156 int nextArg = TETHER_START_CONST_ARG;
157 for (int addrIndex=0; addrIndex < num_addrs;) {
158 char *start = strdup(inet_ntoa(addrs[addrIndex++]));
159 char *end = strdup(inet_ntoa(addrs[addrIndex++]));
160 asprintf(&(args[nextArg++]),"--dhcp-range=%s,%s,1h", start, end);
161 }
162
163 if (execv(args[0], args)) {
164 ALOGE("execl failed (%s)", strerror(errno));
165 }
166 ALOGE("Should never get here!");
167 _exit(-1);
168 } else {
169 close(pipefd[0]);
170 mDaemonPid = pid;
171 mDaemonFd = pipefd[1];
172 applyDnsInterfaces();
173 ALOGD("Tethering services running");
174 }
175
176 return 0;
177 }
178
stopTethering()179 int TetherController::stopTethering() {
180
181 if (mDaemonPid == 0) {
182 ALOGE("Tethering already stopped");
183 return 0;
184 }
185
186 ALOGD("Stopping tethering services");
187
188 kill(mDaemonPid, SIGTERM);
189 waitpid(mDaemonPid, NULL, 0);
190 mDaemonPid = 0;
191 close(mDaemonFd);
192 mDaemonFd = -1;
193 ALOGD("Tethering services stopped");
194 return 0;
195 }
196
isTetheringStarted()197 bool TetherController::isTetheringStarted() {
198 return (mDaemonPid == 0 ? false : true);
199 }
200
201 #define MAX_CMD_SIZE 1024
202
setDnsForwarders(unsigned netId,char ** servers,int numServers)203 int TetherController::setDnsForwarders(unsigned netId, char **servers, int numServers) {
204 int i;
205 char daemonCmd[MAX_CMD_SIZE];
206
207 Fwmark fwmark;
208 fwmark.netId = netId;
209 fwmark.explicitlySelected = true;
210 fwmark.protectedFromVpn = true;
211 fwmark.permission = PERMISSION_SYSTEM;
212
213 snprintf(daemonCmd, sizeof(daemonCmd), "update_dns:0x%x", fwmark.intValue);
214 int cmdLen = strlen(daemonCmd);
215
216 mDnsForwarders->clear();
217 for (i = 0; i < numServers; i++) {
218 ALOGD("setDnsForwarders(0x%x %d = '%s')", fwmark.intValue, i, servers[i]);
219
220 struct in_addr a;
221
222 if (!inet_aton(servers[i], &a)) {
223 ALOGE("Failed to parse DNS server '%s'", servers[i]);
224 mDnsForwarders->clear();
225 return -1;
226 }
227
228 cmdLen += (strlen(servers[i]) + 1);
229 if (cmdLen + 1 >= MAX_CMD_SIZE) {
230 ALOGD("Too many DNS servers listed");
231 break;
232 }
233
234 strcat(daemonCmd, ":");
235 strcat(daemonCmd, servers[i]);
236 mDnsForwarders->push_back(a);
237 }
238
239 mDnsNetId = netId;
240 if (mDaemonFd != -1) {
241 ALOGD("Sending update msg to dnsmasq [%s]", daemonCmd);
242 if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) {
243 ALOGE("Failed to send update command to dnsmasq (%s)", strerror(errno));
244 mDnsForwarders->clear();
245 return -1;
246 }
247 }
248 return 0;
249 }
250
getDnsNetId()251 unsigned TetherController::getDnsNetId() {
252 return mDnsNetId;
253 }
254
getDnsForwarders()255 NetAddressCollection *TetherController::getDnsForwarders() {
256 return mDnsForwarders;
257 }
258
applyDnsInterfaces()259 int TetherController::applyDnsInterfaces() {
260 char daemonCmd[MAX_CMD_SIZE];
261
262 strcpy(daemonCmd, "update_ifaces");
263 int cmdLen = strlen(daemonCmd);
264 InterfaceCollection::iterator it;
265 bool haveInterfaces = false;
266
267 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
268 cmdLen += (strlen(*it) + 1);
269 if (cmdLen + 1 >= MAX_CMD_SIZE) {
270 ALOGD("Too many DNS ifaces listed");
271 break;
272 }
273
274 strcat(daemonCmd, ":");
275 strcat(daemonCmd, *it);
276 haveInterfaces = true;
277 }
278
279 if ((mDaemonFd != -1) && haveInterfaces) {
280 ALOGD("Sending update msg to dnsmasq [%s]", daemonCmd);
281 if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) {
282 ALOGE("Failed to send update command to dnsmasq (%s)", strerror(errno));
283 return -1;
284 }
285 }
286 return 0;
287 }
288
tetherInterface(const char * interface)289 int TetherController::tetherInterface(const char *interface) {
290 ALOGD("tetherInterface(%s)", interface);
291 if (!isIfaceName(interface)) {
292 errno = ENOENT;
293 return -1;
294 }
295 mInterfaces->push_back(strdup(interface));
296
297 if (applyDnsInterfaces()) {
298 InterfaceCollection::iterator it;
299 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
300 if (!strcmp(interface, *it)) {
301 free(*it);
302 mInterfaces->erase(it);
303 break;
304 }
305 }
306 return -1;
307 } else {
308 return 0;
309 }
310 }
311
untetherInterface(const char * interface)312 int TetherController::untetherInterface(const char *interface) {
313 InterfaceCollection::iterator it;
314
315 ALOGD("untetherInterface(%s)", interface);
316
317 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
318 if (!strcmp(interface, *it)) {
319 free(*it);
320 mInterfaces->erase(it);
321
322 return applyDnsInterfaces();
323 }
324 }
325 errno = ENOENT;
326 return -1;
327 }
328
getTetheredInterfaceList()329 InterfaceCollection *TetherController::getTetheredInterfaceList() {
330 return mInterfaces;
331 }
332