network/netmgr/commands/wifi_command.cpp - device/generic/goldfish - Git at Google

 /*
  * Copyright 2018, 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 "wifi_command.h"

 #include "../fork.h"
 #include "log.h"

 #include <cutils/properties.h>
 #include <errno.h>
 #include <net/if.h>
 #include <netinet/in.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <unistd.h>

 static const char kHostApdStubFile[] = "/vendor/etc/simulated_hostapd.conf";
 static const char kHostApdConfFile[] = "/data/vendor/wifi/hostapd/hostapd.conf";

 static const char kControlRestartProperty[] = "ctl.restart";
 static const char kHostApdServiceName[] = "emu_hostapd";

 static const char kIfNamePrefix[] = "wlan1_";

 class File {
 public:
     explicit File(FILE* file) : mFile(file) {}
     ~File() {
         if (mFile) {
             fclose(mFile);
         }
     }

     FILE* get() { return mFile; }

     bool operator!() const { return mFile == nullptr; }
 private:
     FILE* mFile;
 };

 class Fd {
 public:
     explicit Fd(int fd) : mFd(fd) {}
     ~Fd() {
         if (mFd != -1) {
             ::close(mFd);
             mFd = -1;
         }
     }

     int get() const { return mFd; }

 private:
     int mFd;
 };

 std::vector<std::string> explode(const char* str) {
     const char* cur = str;
     const char* space = nullptr;
     std::vector<std::string> result;
     do {
         space = ::strchr(cur, ' ');
         if (space) {
             result.emplace_back(cur, space);
             cur = space + 1;
         } else {
             result.emplace_back(cur);
         }
     } while (space);

     return result;
 }

 WifiCommand::WifiCommand() : mLowestInterfaceNumber(1) {
     readConfig();
 }

 Result WifiCommand::onCommand(const char* /*command*/, const char* args) {
     const char* divider = ::strchr(args, ' ');
     if (divider == nullptr) {
         // Unknown command, every command needs an argument
         return Result::error("Invalid wifi command '%s'", args);
     }

     std::string subCommand(args, divider);
     if (subCommand.empty()) {
         return Result::error("Empty wifi command");
     }

     std::vector<std::string> subArgs = explode(divider + 1);
     if (subArgs.empty()) {
         // All of these commands require sub arguments
         return Result::error("Missing argument to command '%s'",
                              subCommand.c_str());
     }

     if (subCommand == "add") {
         return onAdd(subArgs);
     } else if (subCommand == "block") {
         return onBlock(subArgs);
     } else if (subCommand == "unblock") {
         return onUnblock(subArgs);
     } else {
         return Result::error("Unknown wifi command '%s'", subCommand.c_str());
     }
 }

 void WifiCommand::readConfig() {
 }

 Result WifiCommand::writeConfig() {
     File in(fopen(kHostApdStubFile, "r"));
     if (!in) {
         return Result::error("Config failure: could not open template: %s",
                              strerror(errno));
     }

     File out(fopen(kHostApdConfFile, "w"));
     if (!out) {
         return Result::error("Config failure: could not open target: %s",
                              strerror(errno));
     }

     char buffer[32768];
     while (!feof(in.get())) {
         size_t bytesRead = fread(buffer, 1, sizeof(buffer), in.get());
         if (bytesRead != sizeof(buffer) && ferror(in.get())) {
             return Result::error("Config failure: Error reading template: %s",
                                  strerror(errno));
         }

         size_t bytesWritten = fwrite(buffer, 1, bytesRead, out.get());
         if (bytesWritten != bytesRead) {
             return Result::error("Config failure: Error writing target: %s",
                                  strerror(errno));
         }
     }
     fprintf(out.get(), "\n\n");

     for (const auto& ap : mAccessPoints) {
         fprintf(out.get(), "bss=%s\n", ap.second.ifName.c_str());
         fprintf(out.get(), "ssid=%s\n", ap.second.ssid.c_str());
         if (!ap.second.password.empty()) {
             fprintf(out.get(), "wpa=2\n");
             fprintf(out.get(), "wpa_key_mgmt=WPA-PSK\n");
             fprintf(out.get(), "rsn_pairwise=CCMP\n");
             fprintf(out.get(), "wpa_passphrase=%s\n", ap.second.password.c_str());
         }
         fprintf(out.get(), "\n");
     }
     return Result::success();
 }

 Result WifiCommand::triggerHostApd() {
     property_set(kControlRestartProperty, kHostApdServiceName);
     return Result::success();
 }

 static const char* sSetForwardRule[] = {"/system/bin/iptables",
                                         "-w",    // Wait for iptables lock if
                                         "-W",    // needed. This prevents
                                         "50000", // spurious failures.
                                         "<AddOrDelete>", // To be replaced
                                         "FORWARD",
                                         "-i",
                                         "<InInterface>", // To be replaced
                                         "-o",
                                         "<OutInterface>", // To be replaced
                                         "-j",
                                         "DROP",
                                         nullptr };

 static const char kIpTables[] = "/system/bin/iptables";
 static const char kIp6Tables[] = "/system/bin/ip6tables";
 static const char kAddRule[] = "-A";
 static const char kDeleteRule[] = "-D";
 static const size_t kIpTablesIndex = 0;
 static const size_t kActionIndex = 4;
 static const size_t kInInterfaceIndex = 7;
 static const size_t kOutInterfaceIndex = 9;


 Result WifiCommand::setBlocked(const char* ifName, bool blocked) {
     // Blocking means adding block rules, unblocking means removing them
     sSetForwardRule[kActionIndex] = blocked ? kAddRule : kDeleteRule;

     // Do this for both IPv4 and IPv6 to ensure all traffic is blocked/unblocked
     for (const auto& iptables : { kIpTables, kIp6Tables }) {
         // Block traffic coming in from the outside world to this wlan
         sSetForwardRule[kIpTablesIndex] = iptables;
         sSetForwardRule[kInInterfaceIndex] = "eth0";
         sSetForwardRule[kOutInterfaceIndex] = ifName;
         if (!forkAndExec(sSetForwardRule)) {
             return Result::error("Internal error: Unable to %s network",
                                  blocked ? "block" : "unblock");
         }
         // Block traffic going from the wlan to the outside world
         sSetForwardRule[kInInterfaceIndex] = ifName;
         sSetForwardRule[kOutInterfaceIndex] = "eth0";
         if (!forkAndExec(sSetForwardRule)) {
             return Result::error("Internal error: Unable to %s network",
                                  blocked ? "block" : "unblock");
         }
     }
     return Result::success();
 }

 Result WifiCommand::onAdd(const std::vector<std::string>& arguments) {
     AccessPoint& ap = mAccessPoints[arguments[0]];
     ap.ssid = arguments[0];
     if (arguments.size() > 1) {
         ap.password = arguments[1];
     } else {
         ap.password.clear();
     }
     if (ap.ifName.empty()) {
         char buffer[sizeof(kIfNamePrefix) + 10];
         while (true) {
             snprintf(buffer, sizeof(buffer), "%s%d",
                      kIfNamePrefix, mLowestInterfaceNumber);
             ap.ifName = buffer;
             auto usedInterface = mUsedInterfaces.find(ap.ifName);
             if (usedInterface == mUsedInterfaces.end()) {
                 // This interface is available, use it
                 ++mLowestInterfaceNumber;
                 mUsedInterfaces.insert(ap.ifName);
                 break;
             }
             // The interface name was alread in use, try the next one
             ++mLowestInterfaceNumber;
         }
     }
     Result res = writeConfig();
     if (!res) {
         return res;
     }
     return triggerHostApd();
 }

 Result WifiCommand::onBlock(const std::vector<std::string>& arguments) {
     auto interface = mAccessPoints.find(arguments[0]);
     if (interface == mAccessPoints.end()) {
         return Result::error("Unknown SSID '%s", arguments[0].c_str());
     }
     interface->second.blocked = true;
     return setBlocked(interface->second.ifName.c_str(), true);
 }

 Result WifiCommand::onUnblock(const std::vector<std::string>& arguments) {
     auto interface = mAccessPoints.find(arguments[0]);
     if (interface == mAccessPoints.end()) {
         return Result::error("Unknown SSID '%s", arguments[0].c_str());
     }
     interface->second.blocked = false;
     return setBlocked(interface->second.ifName.c_str(), false);
 }
	/*
	* Copyright 2018, 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 "wifi_command.h"

	#include "../fork.h"
	#include "log.h"

	#include <cutils/properties.h>
	#include <errno.h>
	#include <net/if.h>
	#include <netinet/in.h>
	#include <stdio.h>
	#include <string.h>
	#include <sys/ioctl.h>
	#include <sys/socket.h>
	#include <sys/types.h>
	#include <unistd.h>

	static const char kHostApdStubFile[] = "/vendor/etc/simulated_hostapd.conf";
	static const char kHostApdConfFile[] = "/data/vendor/wifi/hostapd/hostapd.conf";

	static const char kControlRestartProperty[] = "ctl.restart";
	static const char kHostApdServiceName[] = "emu_hostapd";

	static const char kIfNamePrefix[] = "wlan1_";

	class File {
	public:
	explicit File(FILE* file) : mFile(file) {}
	~File() {
	if (mFile) {
	fclose(mFile);
	}
	}

	FILE* get() { return mFile; }

	bool operator!() const { return mFile == nullptr; }
	private:
	FILE* mFile;
	};

	class Fd {
	public:
	explicit Fd(int fd) : mFd(fd) {}
	~Fd() {
	if (mFd != -1) {
	::close(mFd);
	mFd = -1;
	}
	}

	int get() const { return mFd; }

	private:
	int mFd;
	};

	std::vector<std::string> explode(const char* str) {
	const char* cur = str;
	const char* space = nullptr;
	std::vector<std::string> result;
	do {
	space = ::strchr(cur, ' ');
	if (space) {
	result.emplace_back(cur, space);
	cur = space + 1;
	} else {
	result.emplace_back(cur);
	}
	} while (space);

	return result;
	}

	WifiCommand::WifiCommand() : mLowestInterfaceNumber(1) {
	readConfig();
	}

	Result WifiCommand::onCommand(const char* /command/, const char* args) {
	const char* divider = ::strchr(args, ' ');
	if (divider == nullptr) {
	// Unknown command, every command needs an argument
	return Result::error("Invalid wifi command '%s'", args);
	}

	std::string subCommand(args, divider);
	if (subCommand.empty()) {
	return Result::error("Empty wifi command");
	}

	std::vector<std::string> subArgs = explode(divider + 1);
	if (subArgs.empty()) {
	// All of these commands require sub arguments
	return Result::error("Missing argument to command '%s'",
	subCommand.c_str());
	}

	if (subCommand == "add") {
	return onAdd(subArgs);
	} else if (subCommand == "block") {
	return onBlock(subArgs);
	} else if (subCommand == "unblock") {
	return onUnblock(subArgs);
	} else {
	return Result::error("Unknown wifi command '%s'", subCommand.c_str());
	}
	}

	void WifiCommand::readConfig() {
	}

	Result WifiCommand::writeConfig() {
	File in(fopen(kHostApdStubFile, "r"));
	if (!in) {
	return Result::error("Config failure: could not open template: %s",
	strerror(errno));
	}

	File out(fopen(kHostApdConfFile, "w"));
	if (!out) {
	return Result::error("Config failure: could not open target: %s",
	strerror(errno));
	}

	char buffer[32768];
	while (!feof(in.get())) {
	size_t bytesRead = fread(buffer, 1, sizeof(buffer), in.get());
	if (bytesRead != sizeof(buffer) && ferror(in.get())) {
	return Result::error("Config failure: Error reading template: %s",
	strerror(errno));
	}

	size_t bytesWritten = fwrite(buffer, 1, bytesRead, out.get());
	if (bytesWritten != bytesRead) {
	return Result::error("Config failure: Error writing target: %s",
	strerror(errno));
	}
	}
	fprintf(out.get(), "\n\n");

	for (const auto& ap : mAccessPoints) {
	fprintf(out.get(), "bss=%s\n", ap.second.ifName.c_str());
	fprintf(out.get(), "ssid=%s\n", ap.second.ssid.c_str());
	if (!ap.second.password.empty()) {
	fprintf(out.get(), "wpa=2\n");
	fprintf(out.get(), "wpa_key_mgmt=WPA-PSK\n");
	fprintf(out.get(), "rsn_pairwise=CCMP\n");
	fprintf(out.get(), "wpa_passphrase=%s\n", ap.second.password.c_str());
	}
	fprintf(out.get(), "\n");
	}
	return Result::success();
	}

	Result WifiCommand::triggerHostApd() {
	property_set(kControlRestartProperty, kHostApdServiceName);
	return Result::success();
	}

	static const char* sSetForwardRule[] = {"/system/bin/iptables",
	"-w", // Wait for iptables lock if
	"-W", // needed. This prevents
	"50000", // spurious failures.
	"<AddOrDelete>", // To be replaced
	"FORWARD",
	"-i",
	"<InInterface>", // To be replaced
	"-o",
	"<OutInterface>", // To be replaced
	"-j",
	"DROP",
	nullptr };

	static const char kIpTables[] = "/system/bin/iptables";
	static const char kIp6Tables[] = "/system/bin/ip6tables";
	static const char kAddRule[] = "-A";
	static const char kDeleteRule[] = "-D";
	static const size_t kIpTablesIndex = 0;
	static const size_t kActionIndex = 4;
	static const size_t kInInterfaceIndex = 7;
	static const size_t kOutInterfaceIndex = 9;


	Result WifiCommand::setBlocked(const char* ifName, bool blocked) {
	// Blocking means adding block rules, unblocking means removing them
	sSetForwardRule[kActionIndex] = blocked ? kAddRule : kDeleteRule;

	// Do this for both IPv4 and IPv6 to ensure all traffic is blocked/unblocked
	for (const auto& iptables : { kIpTables, kIp6Tables }) {
	// Block traffic coming in from the outside world to this wlan
	sSetForwardRule[kIpTablesIndex] = iptables;
	sSetForwardRule[kInInterfaceIndex] = "eth0";
	sSetForwardRule[kOutInterfaceIndex] = ifName;
	if (!forkAndExec(sSetForwardRule)) {
	return Result::error("Internal error: Unable to %s network",
	blocked ? "block" : "unblock");
	}
	// Block traffic going from the wlan to the outside world
	sSetForwardRule[kInInterfaceIndex] = ifName;
	sSetForwardRule[kOutInterfaceIndex] = "eth0";
	if (!forkAndExec(sSetForwardRule)) {
	return Result::error("Internal error: Unable to %s network",
	blocked ? "block" : "unblock");
	}
	}
	return Result::success();
	}

	Result WifiCommand::onAdd(const std::vector<std::string>& arguments) {
	AccessPoint& ap = mAccessPoints[arguments[0]];
	ap.ssid = arguments[0];
	if (arguments.size() > 1) {
	ap.password = arguments[1];
	} else {
	ap.password.clear();
	}
	if (ap.ifName.empty()) {
	char buffer[sizeof(kIfNamePrefix) + 10];
	while (true) {
	snprintf(buffer, sizeof(buffer), "%s%d",
	kIfNamePrefix, mLowestInterfaceNumber);
	ap.ifName = buffer;
	auto usedInterface = mUsedInterfaces.find(ap.ifName);
	if (usedInterface == mUsedInterfaces.end()) {
	// This interface is available, use it
	++mLowestInterfaceNumber;
	mUsedInterfaces.insert(ap.ifName);
	break;
	}
	// The interface name was alread in use, try the next one
	++mLowestInterfaceNumber;
	}
	}
	Result res = writeConfig();
	if (!res) {
	return res;
	}
	return triggerHostApd();
	}

	Result WifiCommand::onBlock(const std::vector<std::string>& arguments) {
	auto interface = mAccessPoints.find(arguments[0]);
	if (interface == mAccessPoints.end()) {
	return Result::error("Unknown SSID '%s", arguments[0].c_str());
	}
	interface->second.blocked = true;
	return setBlocked(interface->second.ifName.c_str(), true);
	}

	Result WifiCommand::onUnblock(const std::vector<std::string>& arguments) {
	auto interface = mAccessPoints.find(arguments[0]);
	if (interface == mAccessPoints.end()) {
	return Result::error("Unknown SSID '%s", arguments[0].c_str());
	}
	interface->second.blocked = false;
	return setBlocked(interface->second.ifName.c_str(), false);
	}