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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define LOG_TAG "TetherController"
#include <cutils/log.h>
#include <cutils/properties.h>
#include "TetherController.h"
TetherController::TetherController() {
mInterfaces = new InterfaceCollection();
mDnsForwarders = new NetAddressCollection();
mDaemonFd = -1;
mDaemonPid = 0;
}
TetherController::~TetherController() {
InterfaceCollection::iterator it;
for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
free(*it);
}
mInterfaces->clear();
mDnsForwarders->clear();
}
int TetherController::setIpFwdEnabled(bool enable) {
ALOGD("Setting IP forward enable = %d", enable);
// In BP tools mode, do not disable IP forwarding
char bootmode[PROPERTY_VALUE_MAX] = {0};
property_get("ro.bootmode", bootmode, "unknown");
if ((enable == false) && (0 == strcmp("bp-tools", bootmode))) {
return 0;
}
int fd = open("/proc/sys/net/ipv4/ip_forward", O_WRONLY);
if (fd < 0) {
ALOGE("Failed to open ip_forward (%s)", strerror(errno));
return -1;
}
if (write(fd, (enable ? "1" : "0"), 1) != 1) {
ALOGE("Failed to write ip_forward (%s)", strerror(errno));
close(fd);
return -1;
}
close(fd);
return 0;
}
bool TetherController::getIpFwdEnabled() {
int fd = open("/proc/sys/net/ipv4/ip_forward", O_RDONLY);
if (fd < 0) {
ALOGE("Failed to open ip_forward (%s)", strerror(errno));
return false;
}
char enabled;
if (read(fd, &enabled, 1) != 1) {
ALOGE("Failed to read ip_forward (%s)", strerror(errno));
close(fd);
return -1;
}
close(fd);
return (enabled == '1' ? true : false);
}
#define TETHER_START_CONST_ARG 8
int TetherController::startTethering(int num_addrs, struct in_addr* addrs) {
if (mDaemonPid != 0) {
ALOGE("Tethering already started");
errno = EBUSY;
return -1;
}
ALOGD("Starting tethering services");
pid_t pid;
int pipefd[2];
if (pipe(pipefd) < 0) {
ALOGE("pipe failed (%s)", strerror(errno));
return -1;
}
/*
* TODO: Create a monitoring thread to handle and restart
* the daemon if it exits prematurely
*/
if ((pid = fork()) < 0) {
ALOGE("fork failed (%s)", strerror(errno));
close(pipefd[0]);
close(pipefd[1]);
return -1;
}
if (!pid) {
close(pipefd[1]);
if (pipefd[0] != STDIN_FILENO) {
if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) {
ALOGE("dup2 failed (%s)", strerror(errno));
return -1;
}
close(pipefd[0]);
}
int num_processed_args = TETHER_START_CONST_ARG + (num_addrs/2) + 1;
char **args = (char **)malloc(sizeof(char *) * num_processed_args);
args[num_processed_args - 1] = NULL;
args[0] = (char *)"/system/bin/dnsmasq";
args[1] = (char *)"--keep-in-foreground";
args[2] = (char *)"--no-resolv";
args[3] = (char *)"--no-poll";
args[4] = (char *)"--dhcp-authoritative";
// TODO: pipe through metered status from ConnService
args[5] = (char *)"--dhcp-option-force=43,ANDROID_METERED";
args[6] = (char *)"--pid-file";
args[7] = (char *)"";
int nextArg = TETHER_START_CONST_ARG;
for (int addrIndex=0; addrIndex < num_addrs;) {
char *start = strdup(inet_ntoa(addrs[addrIndex++]));
char *end = strdup(inet_ntoa(addrs[addrIndex++]));
asprintf(&(args[nextArg++]),"--dhcp-range=%s,%s,1h", start, end);
}
if (execv(args[0], args)) {
ALOGE("execl failed (%s)", strerror(errno));
}
ALOGE("Should never get here!");
_exit(-1);
} else {
close(pipefd[0]);
mDaemonPid = pid;
mDaemonFd = pipefd[1];
applyDnsInterfaces();
ALOGD("Tethering services running");
}
return 0;
}
int TetherController::stopTethering() {
if (mDaemonPid == 0) {
ALOGE("Tethering already stopped");
return 0;
}
ALOGD("Stopping tethering services");
kill(mDaemonPid, SIGTERM);
waitpid(mDaemonPid, NULL, 0);
mDaemonPid = 0;
close(mDaemonFd);
mDaemonFd = -1;
ALOGD("Tethering services stopped");
return 0;
}
bool TetherController::isTetheringStarted() {
return (mDaemonPid == 0 ? false : true);
}
#define MAX_CMD_SIZE 1024
int TetherController::setDnsForwarders(char **servers, int numServers) {
int i;
char daemonCmd[MAX_CMD_SIZE];
strcpy(daemonCmd, "update_dns");
int cmdLen = strlen(daemonCmd);
mDnsForwarders->clear();
for (i = 0; i < numServers; i++) {
ALOGD("setDnsForwarders(%d = '%s')", i, servers[i]);
struct in_addr a;
if (!inet_aton(servers[i], &a)) {
ALOGE("Failed to parse DNS server '%s'", servers[i]);
mDnsForwarders->clear();
return -1;
}
cmdLen += (strlen(servers[i]) + 1);
if (cmdLen + 1 >= MAX_CMD_SIZE) {
ALOGD("Too many DNS servers listed");
break;
}
strcat(daemonCmd, ":");
strcat(daemonCmd, servers[i]);
mDnsForwarders->push_back(a);
}
if (mDaemonFd != -1) {
ALOGD("Sending update msg to dnsmasq [%s]", daemonCmd);
if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) {
ALOGE("Failed to send update command to dnsmasq (%s)", strerror(errno));
mDnsForwarders->clear();
return -1;
}
}
return 0;
}
NetAddressCollection *TetherController::getDnsForwarders() {
return mDnsForwarders;
}
int TetherController::applyDnsInterfaces() {
int i;
char daemonCmd[MAX_CMD_SIZE];
strcpy(daemonCmd, "update_ifaces");
int cmdLen = strlen(daemonCmd);
InterfaceCollection::iterator it;
bool haveInterfaces = false;
for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
cmdLen += (strlen(*it) + 1);
if (cmdLen + 1 >= MAX_CMD_SIZE) {
ALOGD("Too many DNS ifaces listed");
break;
}
strcat(daemonCmd, ":");
strcat(daemonCmd, *it);
haveInterfaces = true;
}
if ((mDaemonFd != -1) && haveInterfaces) {
ALOGD("Sending update msg to dnsmasq [%s]", daemonCmd);
if (write(mDaemonFd, daemonCmd, strlen(daemonCmd) +1) < 0) {
ALOGE("Failed to send update command to dnsmasq (%s)", strerror(errno));
return -1;
}
}
return 0;
}
int TetherController::tetherInterface(const char *interface) {
ALOGD("tetherInterface(%s)", interface);
mInterfaces->push_back(strdup(interface));
if (applyDnsInterfaces()) {
InterfaceCollection::iterator it;
for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
if (!strcmp(interface, *it)) {
free(*it);
mInterfaces->erase(it);
break;
}
}
return -1;
} else {
return 0;
}
}
int TetherController::untetherInterface(const char *interface) {
InterfaceCollection::iterator it;
ALOGD("untetherInterface(%s)", interface);
for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
if (!strcmp(interface, *it)) {
free(*it);
mInterfaces->erase(it);
return applyDnsInterfaces();
}
}
errno = ENOENT;
return -1;
}
InterfaceCollection *TetherController::getTetheredInterfaceList() {
return mInterfaces;
}