TetherController.cpp - platform/system/netd - Git at Google

 /*
  * 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;
     mDhcpcdPid = 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);
 }

 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 = 7 + (num_addrs/2) + 1; // 1 null for termination
         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";
         // TODO: pipe through metered status from ConnService
         args[4] = (char *)"--dhcp-option-force=43,ANDROID_METERED";
         args[5] = (char *)"--pid-file";
         args[6] = (char *)"";

         int nextArg = 7;
         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!");
         free(args);
         return 0;
     } else {
         close(pipefd[0]);
         mDaemonPid = pid;
         mDaemonFd = pipefd[1];
         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;
 }

 // TODO(BT) remove
 int TetherController::startReverseTethering(const char* iface) {
     if (mDhcpcdPid != 0) {
         ALOGE("Reverse tethering already started");
         errno = EBUSY;
         return -1;
     }

     ALOGD("TetherController::startReverseTethering, Starting reverse tethering");

     /*
      * TODO: Create a monitoring thread to handle and restart
      * the daemon if it exits prematurely
      */
     //cleanup the dhcp result
     char dhcp_result_name[64];
     snprintf(dhcp_result_name, sizeof(dhcp_result_name) - 1, "dhcp.%s.result", iface);
     property_set(dhcp_result_name, "");

     pid_t pid;
     if ((pid = fork()) < 0) {
         ALOGE("fork failed (%s)", strerror(errno));
         return -1;
     }

     if (!pid) {

         char *args[10];
         int argc = 0;
         args[argc++] = "/system/bin/dhcpcd";
         char host_name[128];
         if (property_get("net.hostname", host_name, NULL) && (host_name[0] != '\0'))
         {
             args[argc++] = "-h";
             args[argc++] = host_name;
         }
         args[argc++] = (char*)iface;
         args[argc] = NULL;
         if (execv(args[0], args)) {
             ALOGE("startReverseTethering, execv failed (%s)", strerror(errno));
         }
         ALOGE("startReverseTethering, Should never get here!");
         // TODO(BT) inform parent of the failure.
         //          Parent process need wait for child to report error status
         //          before it set mDhcpcdPid and return 0.
         exit(-1);
     } else {
         mDhcpcdPid = pid;
         ALOGD("Reverse Tethering running, pid:%d", pid);
     }
     return 0;
 }

 // TODO(BT) remove
 int TetherController::stopReverseTethering() {

     if (mDhcpcdPid == 0) {
         ALOGE("Tethering already stopped");
         return 0;
     }

     ALOGD("Stopping tethering services");

     kill(mDhcpcdPid, SIGTERM);
     waitpid(mDhcpcdPid, NULL, 0);
     mDhcpcdPid = 0;
     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::tetherInterface(const char *interface) {
     mInterfaces->push_back(strdup(interface));
     return 0;
 }

 int TetherController::untetherInterface(const char *interface) {
     InterfaceCollection::iterator it;

     for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
         if (!strcmp(interface, *it)) {
             free(*it);
             mInterfaces->erase(it);
             return 0;
         }
     }
     errno = ENOENT;
     return -1;
 }

 InterfaceCollection *TetherController::getTetheredInterfaceList() {
     return mInterfaces;
 }
	/*
	* 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;
	mDhcpcdPid = 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);
	}

	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 = 7 + (num_addrs/2) + 1; // 1 null for termination
	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";
	// TODO: pipe through metered status from ConnService
	args[4] = (char *)"--dhcp-option-force=43,ANDROID_METERED";
	args[5] = (char *)"--pid-file";
	args[6] = (char *)"";

	int nextArg = 7;
	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!");
	free(args);
	return 0;
	} else {
	close(pipefd[0]);
	mDaemonPid = pid;
	mDaemonFd = pipefd[1];
	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;
	}

	// TODO(BT) remove
	int TetherController::startReverseTethering(const char* iface) {
	if (mDhcpcdPid != 0) {
	ALOGE("Reverse tethering already started");
	errno = EBUSY;
	return -1;
	}

	ALOGD("TetherController::startReverseTethering, Starting reverse tethering");

	/*
	* TODO: Create a monitoring thread to handle and restart
	* the daemon if it exits prematurely
	*/
	//cleanup the dhcp result
	char dhcp_result_name[64];
	snprintf(dhcp_result_name, sizeof(dhcp_result_name) - 1, "dhcp.%s.result", iface);
	property_set(dhcp_result_name, "");

	pid_t pid;
	if ((pid = fork()) < 0) {
	ALOGE("fork failed (%s)", strerror(errno));
	return -1;
	}

	if (!pid) {

	char *args[10];
	int argc = 0;
	args[argc++] = "/system/bin/dhcpcd";
	char host_name[128];
	if (property_get("net.hostname", host_name, NULL) && (host_name[0] != '\0'))
	{
	args[argc++] = "-h";
	args[argc++] = host_name;
	}
	args[argc++] = (char*)iface;
	args[argc] = NULL;
	if (execv(args[0], args)) {
	ALOGE("startReverseTethering, execv failed (%s)", strerror(errno));
	}
	ALOGE("startReverseTethering, Should never get here!");
	// TODO(BT) inform parent of the failure.
	// Parent process need wait for child to report error status
	// before it set mDhcpcdPid and return 0.
	exit(-1);
	} else {
	mDhcpcdPid = pid;
	ALOGD("Reverse Tethering running, pid:%d", pid);
	}
	return 0;
	}

	// TODO(BT) remove
	int TetherController::stopReverseTethering() {

	if (mDhcpcdPid == 0) {
	ALOGE("Tethering already stopped");
	return 0;
	}

	ALOGD("Stopping tethering services");

	kill(mDhcpcdPid, SIGTERM);
	waitpid(mDhcpcdPid, NULL, 0);
	mDhcpcdPid = 0;
	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::tetherInterface(const char *interface) {
	mInterfaces->push_back(strdup(interface));
	return 0;
	}

	int TetherController::untetherInterface(const char *interface) {
	InterfaceCollection::iterator it;

	for (it = mInterfaces->begin(); it != mInterfaces->end(); ++it) {
	if (!strcmp(interface, *it)) {
	free(*it);
	mInterfaces->erase(it);
	return 0;
	}
	}
	errno = ENOENT;
	return -1;
	}

	InterfaceCollection *TetherController::getTetheredInterfaceList() {
	return mInterfaces;
	}