TetherController.cpp revision 18737845d3c6a60edd6f75ac441a1b3fed6d66a7 
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
21#include <sys/socket.h>
22#include <sys/stat.h>
23#include <sys/types.h>
24#include <sys/wait.h>
25
26#include <netinet/in.h>
27#include <arpa/inet.h>
28
29#define LOG_TAG "TetherController"
30#include <cutils/log.h>
31
32
33#include "TetherController.h"
34
35TetherController::TetherController() {
36    mInterfaces = new InterfaceCollection();
37    mDnsForwarders = new NetAddressCollection();
38    mDaemonFd = -1;
39    mDaemonPid = 0;
40}
41
42TetherController::~TetherController() {
43    InterfaceCollection::iterator it;
44
45    for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
46        free(*it);
47    }
48    mInterfaces->clear();
49
50    mDnsForwarders->clear();
51}
52
53int TetherController::setIpFwdEnabled(bool enable) {
54
55    LOGD("Setting IP forward enable = %d", enable);
56    int fd = open("/proc/sys/net/ipv4/ip_forward", O_WRONLY);
57    if (fd < 0) {
58        LOGE("Failed to open ip_forward (%s)", strerror(errno));
59        return -1;
60    }
61
62    if (write(fd, (enable ? "1" : "0"), 1) != 1) {
63        LOGE("Failed to write ip_forward (%s)", strerror(errno));
64        return -1;
65    }
66    close(fd);
67    return 0;
68}
69
70bool TetherController::getIpFwdEnabled() {
71    int fd = open("/proc/sys/net/ipv4/ip_forward", O_RDONLY);
72
73    if (fd < 0) {
74        LOGE("Failed to open ip_forward (%s)", strerror(errno));
75        return false;
76    }
77
78    char enabled;
79    if (read(fd, &enabled, 1) != 1) {
80        LOGE("Failed to read ip_forward (%s)", strerror(errno));
81        return -1;
82    }
83
84    close(fd);
85
86    return (enabled  == '1' ? true : false);
87}
88
89int TetherController::startTethering(struct in_addr dhcpStart, struct in_addr dhcpEnd) {
90
91    if (mDaemonPid != 0) {
92        LOGE("Tethering already started");
93        errno = EBUSY;
94        return -1;
95    }
96
97    LOGD("Starting tethering services");
98
99    pid_t pid;
100    int pipefd[2];
101
102    if (pipe(pipefd) < 0) {
103        LOGE("pipe failed (%s)", strerror(errno));
104        return -1;
105    }
106
107    /*
108     * TODO: Create a monitoring thread to handle and restart
109     * the daemon if it exits prematurely
110     */
111    if ((pid = fork()) < 0) {
112        LOGE("fork failed (%s)", strerror(errno));
113        close(pipefd[0]);
114        close(pipefd[1]);
115        return -1;
116    }
117
118    if (!pid) {
119        close(pipefd[1]);
120        if (pipefd[0] != STDIN_FILENO) {
121            if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) {
122                LOGE("dup2 failed (%s)", strerror(errno));
123                return -1;
124            }
125            close(pipefd[0]);
126        }
127        char *start = strdup(inet_ntoa(dhcpStart));
128        char *end = strdup(inet_ntoa(dhcpEnd));
129        char *range;
130
131        asprintf(&range, "--dhcp-range=%s,%s,1h", start, end);
132
133        if (execl("/system/bin/dnsmasq", "/system/bin/dnsmasq", "--no-daemon", "--no-resolv",
134                  "--no-poll", "--no-hosts", range, (char *) NULL)) {
135            LOGE("execl failed (%s)", strerror(errno));
136        }
137        LOGE("Should never get here!");
138        return 0;
139    } else {
140        close(pipefd[0]);
141        mDaemonPid = pid;
142        mDaemonFd = pipefd[1];
143        LOGD("Tethering services running");
144    }
145
146    return 0;
147}
148
149int TetherController::stopTethering() {
150
151    if (mDaemonPid == 0) {
152        LOGE("Tethering already stopped");
153        return 0;
154    }
155
156    LOGD("Stopping tethering services");
157
158    kill(mDaemonPid, SIGTERM);
159    waitpid(mDaemonPid, NULL, 0);
160    mDaemonPid = 0;
161    close(mDaemonFd);
162    mDaemonFd = -1;
163    LOGD("Tethering services stopped");
164    return 0;
165}
166
167bool TetherController::isTetheringStarted() {
168    return (mDaemonPid == 0 ? false : true);
169}
170
171int TetherController::setDnsForwarders(char **servers, int numServers) {
172    int i;
173    char daemonCmd[1024];
174
175    strcpy(daemonCmd, "update_dns");
176
177    mDnsForwarders->clear();
178    for (i = 0; i < numServers; i++) {
179        LOGD("setDnsForwarders(%d = '%s')", i, servers[i]);
180
181        struct in_addr a;
182
183        if (!inet_aton(servers[i], &a)) {
184            LOGE("Failed to parse DNS server '%s'", servers[i]);
185            mDnsForwarders->clear();
186            return -1;
187        }
188        strcat(daemonCmd, ":");
189        strcat(daemonCmd, servers[i]);
190        mDnsForwarders->push_back(a);
191    }
192
193    if (mDaemonFd != -1) {
194        LOGD("Sending update msg to dnsmasq [%s]", daemonCmd);
195        if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) {
196            LOGE("Failed to send update command to dnsmasq (%s)", strerror(errno));
197            mDnsForwarders->clear();
198            return -1;
199        }
200    }
201    return 0;
202}
203
204NetAddressCollection *TetherController::getDnsForwarders() {
205    return mDnsForwarders;
206}
207
208int TetherController::tetherInterface(const char *interface) {
209    mInterfaces->push_back(strdup(interface));
210    return 0;
211}
212
213int TetherController::untetherInterface(const char *interface) {
214    InterfaceCollection::iterator it;
215
216    for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
217        if (!strcmp(interface, *it)) {
218            free(*it);
219            mInterfaces->erase(it);
220            return 0;
221        }
222    }
223    errno = ENOENT;
224    return -1;
225}
226
227InterfaceCollection *TetherController::getTetheredInterfaceList() {
228    return mInterfaces;
229}
230
231