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 = 5 + (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 *)"--no-daemon";
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
147 int nextArg = 5;
148 for (int addrIndex=0; addrIndex < num_addrs;) {
149 char *start = strdup(inet_ntoa(addrs[addrIndex++]));
150 char *end = strdup(inet_ntoa(addrs[addrIndex++]));
151 asprintf(&(args[nextArg++]),"--dhcp-range=%s,%s,1h", start, end);
152 }
153
154 if (execv(args[0], args)) {
155 ALOGE("execl failed (%s)", strerror(errno));
156 }
157 ALOGE("Should never get here!");
158 free(args);
159 return 0;
160 } else {
161 close(pipefd[0]);
162 mDaemonPid = pid;
163 mDaemonFd = pipefd[1];
164 ALOGD("Tethering services running");
165 }
166
167 return 0;
168 }
169
stopTethering()170 int TetherController::stopTethering() {
171
172 if (mDaemonPid == 0) {
173 ALOGE("Tethering already stopped");
174 return 0;
175 }
176
177 ALOGD("Stopping tethering services");
178
179 kill(mDaemonPid, SIGTERM);
180 waitpid(mDaemonPid, NULL, 0);
181 mDaemonPid = 0;
182 close(mDaemonFd);
183 mDaemonFd = -1;
184 ALOGD("Tethering services stopped");
185 return 0;
186 }
187
isTetheringStarted()188 bool TetherController::isTetheringStarted() {
189 return (mDaemonPid == 0 ? false : true);
190 }
191
192 #define MAX_CMD_SIZE 1024
193
setDnsForwarders(char ** servers,int numServers)194 int TetherController::setDnsForwarders(char **servers, int numServers) {
195 int i;
196 char daemonCmd[MAX_CMD_SIZE];
197
198 strcpy(daemonCmd, "update_dns");
199 int cmdLen = strlen(daemonCmd);
200
201 mDnsForwarders->clear();
202 for (i = 0; i < numServers; i++) {
203 ALOGD("setDnsForwarders(%d = '%s')", i, servers[i]);
204
205 struct in_addr a;
206
207 if (!inet_aton(servers[i], &a)) {
208 ALOGE("Failed to parse DNS server '%s'", servers[i]);
209 mDnsForwarders->clear();
210 return -1;
211 }
212
213 cmdLen += strlen(servers[i]);
214 if (cmdLen + 2 >= MAX_CMD_SIZE) {
215 ALOGD("Too many DNS servers listed");
216 break;
217 }
218
219 strcat(daemonCmd, ":");
220 strcat(daemonCmd, servers[i]);
221 mDnsForwarders->push_back(a);
222 }
223
224 if (mDaemonFd != -1) {
225 ALOGD("Sending update msg to dnsmasq [%s]", daemonCmd);
226 if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) {
227 ALOGE("Failed to send update command to dnsmasq (%s)", strerror(errno));
228 mDnsForwarders->clear();
229 return -1;
230 }
231 }
232 return 0;
233 }
234
getDnsForwarders()235 NetAddressCollection *TetherController::getDnsForwarders() {
236 return mDnsForwarders;
237 }
238
tetherInterface(const char * interface)239 int TetherController::tetherInterface(const char *interface) {
240 mInterfaces->push_back(strdup(interface));
241 return 0;
242 }
243
untetherInterface(const char * interface)244 int TetherController::untetherInterface(const char *interface) {
245 InterfaceCollection::iterator it;
246
247 for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
248 if (!strcmp(interface, *it)) {
249 free(*it);
250 mInterfaces->erase(it);
251 return 0;
252 }
253 }
254 errno = ENOENT;
255 return -1;
256 }
257
getTetheredInterfaceList()258 InterfaceCollection *TetherController::getTetheredInterfaceList() {
259 return mInterfaces;
260 }
261