Android example source code file (WifiMonitor.java)

This example Android source code file (WifiMonitor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, bssid, connected, disconnected, driver_state, internet, link_speed, max_recv_errors, monitorthread, net, network, regex, scan_results, state-change, state_change, string, terminating, unknown, util, wifimonitor

The WifiMonitor.java Android example source code

/*
 * 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.
 */

package android.net.wifi;

import android.util.Log;
import android.util.Config;
import android.net.NetworkInfo;
import android.net.NetworkStateTracker;

import java.util.regex.Pattern;
import java.util.regex.Matcher;

/**
 * Listens for events from the wpa_supplicant server, and passes them on
 * to the {@link WifiStateTracker} for handling. Runs in its own thread.
 *
 * @hide
 */
public class WifiMonitor {

    private static final String TAG = "WifiMonitor";

    /** Events we receive from the supplicant daemon */

    private static final int CONNECTED    = 1;
    private static final int DISCONNECTED = 2;
    private static final int STATE_CHANGE = 3;
    private static final int SCAN_RESULTS = 4;
    private static final int LINK_SPEED   = 5;
    private static final int TERMINATING  = 6;
    private static final int DRIVER_STATE = 7;
    private static final int UNKNOWN      = 8;

    /** All events coming from the supplicant start with this prefix */
    private static final String eventPrefix = "CTRL-EVENT-";
    private static final int eventPrefixLen = eventPrefix.length();

    /** All WPA events coming from the supplicant start with this prefix */
    private static final String wpaEventPrefix = "WPA:";
    private static final String passwordKeyMayBeIncorrectEvent =
       "pre-shared key may be incorrect";

    /**
     * Names of events from wpa_supplicant (minus the prefix). In the
     * format descriptions, * "<code>x"
     * designates a dynamic value that needs to be parsed out from the event
     * string
     */
    /**
     * <pre>
     * CTRL-EVENT-CONNECTED - Connection to xx:xx:xx:xx:xx:xx completed
     * </pre>
     * <code>xx:xx:xx:xx:xx:xx is the BSSID of the associated access point
     */
    private static final String connectedEvent =    "CONNECTED";
    /**
     * <pre>
     * CTRL-EVENT-DISCONNECTED - Disconnect event - remove keys
     * </pre>
     */
    private static final String disconnectedEvent = "DISCONNECTED";
    /**
     * <pre>
     * CTRL-EVENT-STATE-CHANGE x
     * </pre>
     * <code>x is the numerical value of the new state.
     */
    private static final String stateChangeEvent =  "STATE-CHANGE";
    /**
     * <pre>
     * CTRL-EVENT-SCAN-RESULTS ready
     * </pre>
     */
    private static final String scanResultsEvent =  "SCAN-RESULTS";

    /**
     * <pre>
     * CTRL-EVENT-LINK-SPEED x Mb/s
     * </pre>
     * {@code x} is the link speed in Mb/sec.
     */
    private static final String linkSpeedEvent = "LINK-SPEED";
    /**
     * <pre>
     * CTRL-EVENT-TERMINATING - signal x
     * </pre>
     * <code>x is the signal that caused termination.
     */
    private static final String terminatingEvent =  "TERMINATING";
    /**
     * <pre>
     * CTRL-EVENT-DRIVER-STATE state
     * </pre>
     * <code>state is either STARTED or STOPPED
     */
    private static final String driverStateEvent = "DRIVER-STATE";

    /**
     * Regex pattern for extracting an Ethernet-style MAC address from a string.
     * Matches a strings like the following:<pre>
     * CTRL-EVENT-CONNECTED - Connection to 00:1e:58:ec:d5:6d completed (reauth) [id=1 id_str=]</pre>
     */
    private static Pattern mConnectedEventPattern =
        Pattern.compile("((?:[0-9a-f]{2}:){5}[0-9a-f]{2}) .* \\[id=([0-9]+) ");

    private final WifiStateTracker mWifiStateTracker;

    /**
     * This indicates the supplicant connection for the monitor is closed
     */
    private static final String monitorSocketClosed = "connection closed";

    /**
     * This indicates a read error on the monitor socket conenction
     */
    private static final String wpaRecvError = "recv error";

    /**
     * Tracks consecutive receive errors
     */
    private int mRecvErrors = 0;

    /**
     * Max errors before we close supplicant connection
     */
    private static final int MAX_RECV_ERRORS    = 10;

    public WifiMonitor(WifiStateTracker tracker) {
        mWifiStateTracker = tracker;
    }

    public void startMonitoring() {
        new MonitorThread().start();
    }

    public NetworkStateTracker getNetworkStateTracker() {
        return mWifiStateTracker;
    }

    class MonitorThread extends Thread {
        public MonitorThread() {
            super("WifiMonitor");
        }
        
        public void run() {

            if (connectToSupplicant()) {
                // Send a message indicating that it is now possible to send commands
                // to the supplicant
                mWifiStateTracker.notifySupplicantConnection();
            } else {
                mWifiStateTracker.notifySupplicantLost();
                return;
            }

            //noinspection InfiniteLoopStatement
            for (;;) {
                String eventStr = WifiNative.waitForEvent();

                // Skip logging the common but mostly uninteresting scan-results event
                if (Config.LOGD && eventStr.indexOf(scanResultsEvent) == -1) {
                    Log.v(TAG, "Event [" + eventStr + "]");
                }
                if (!eventStr.startsWith(eventPrefix)) {
                    if (eventStr.startsWith(wpaEventPrefix) &&
                            0 < eventStr.indexOf(passwordKeyMayBeIncorrectEvent)) {
                        handlePasswordKeyMayBeIncorrect();
                    }
                    continue;
                }

                String eventName = eventStr.substring(eventPrefixLen);
                int nameEnd = eventName.indexOf(' ');
                if (nameEnd != -1)
                    eventName = eventName.substring(0, nameEnd);
                if (eventName.length() == 0) {
                    if (Config.LOGD) Log.i(TAG, "Received wpa_supplicant event with empty event name");
                    continue;
                }
                /*
                 * Map event name into event enum
                 */
                int event;
                if (eventName.equals(connectedEvent))
                    event = CONNECTED;
                else if (eventName.equals(disconnectedEvent))
                    event = DISCONNECTED;
                else if (eventName.equals(stateChangeEvent))
                    event = STATE_CHANGE;
                else if (eventName.equals(scanResultsEvent))
                    event = SCAN_RESULTS;
                else if (eventName.equals(linkSpeedEvent))
                    event = LINK_SPEED;
                else if (eventName.equals(terminatingEvent))
                    event = TERMINATING;
                else if (eventName.equals(driverStateEvent)) {
                    event = DRIVER_STATE;
                }
                else
                    event = UNKNOWN;

                String eventData = eventStr;
                if (event == DRIVER_STATE || event == LINK_SPEED)
                    eventData = eventData.split(" ")[1];
                else if (event == STATE_CHANGE) {
                    int ind = eventStr.indexOf(" ");
                    if (ind != -1) {
                        eventData = eventStr.substring(ind + 1);
                    }
                } else {
                    int ind = eventStr.indexOf(" - ");
                    if (ind != -1) {
                        eventData = eventStr.substring(ind + 3);
                    }
                }

                if (event == STATE_CHANGE) {
                    handleSupplicantStateChange(eventData);
                } else if (event == DRIVER_STATE) {
                    handleDriverEvent(eventData);
                } else if (event == TERMINATING) {
                    /**
                     * If monitor socket is closed, we have already
                     * stopped the supplicant, simply exit the monitor thread
                     */
                    if (eventData.startsWith(monitorSocketClosed)) {
                        if (Config.LOGD) {
                            Log.d(TAG, "Monitor socket is closed, exiting thread");
                        }
                        break;
                    }

                    /**
                     * Close the supplicant connection if we see
                     * too many recv errors
                     */
                    if (eventData.startsWith(wpaRecvError)) {
                        if (++mRecvErrors > MAX_RECV_ERRORS) {
                            if (Config.LOGD) {
                                Log.d(TAG, "too many recv errors, closing connection");
                            }
                        } else {
                            continue;
                        }
                    }

                    // notify and exit
                    mWifiStateTracker.notifySupplicantLost();
                    break;
                } else {
                    handleEvent(event, eventData);
                }
                mRecvErrors = 0;
            }
        }

        private boolean connectToSupplicant() {
            int connectTries = 0;

            while (true) {
                if (mWifiStateTracker.connectToSupplicant()) {
                    return true;
                }
                if (connectTries++ < 3) {
                    nap(5);
                } else {
                    break;
                }
            }
            return false;
        }

        private void handlePasswordKeyMayBeIncorrect() {
            mWifiStateTracker.notifyPasswordKeyMayBeIncorrect();
        }

        private void handleDriverEvent(String state) {
            if (state == null) {
                return;
            }
            if (state.equals("STOPPED")) {
                mWifiStateTracker.notifyDriverStopped();
            } else if (state.equals("STARTED")) {
                mWifiStateTracker.notifyDriverStarted();
            } else if (state.equals("HANGED")) {
                mWifiStateTracker.notifyDriverHung();
            }
        }

        /**
         * Handle all supplicant events except STATE-CHANGE
         * @param event the event type
         * @param remainder the rest of the string following the
         * event name and " — "
         */
        void handleEvent(int event, String remainder) {
            switch (event) {
                case DISCONNECTED:
                    handleNetworkStateChange(NetworkInfo.DetailedState.DISCONNECTED, remainder);
                    break;

                case CONNECTED:
                    handleNetworkStateChange(NetworkInfo.DetailedState.CONNECTED, remainder);
                    break;

                case SCAN_RESULTS:
                    mWifiStateTracker.notifyScanResultsAvailable();
                    break;

                case UNKNOWN:
                    break;
            }
        }

        /**
         * Handle the supplicant STATE-CHANGE event
         * @param dataString New supplicant state string in the format:
         * id=network-id state=new-state
         */
        private void handleSupplicantStateChange(String dataString) {
            String[] dataTokens = dataString.split(" ");

            String BSSID = null;
            int networkId = -1;
            int newState  = -1;
            for (String token : dataTokens) {
                String[] nameValue = token.split("=");
                if (nameValue.length != 2) {
                    continue;
                }

                if (nameValue[0].equals("BSSID")) {
                    BSSID = nameValue[1];
                    continue;
                }

                int value;
                try {
                    value = Integer.parseInt(nameValue[1]);
                } catch (NumberFormatException e) {
                    Log.w(TAG, "STATE-CHANGE non-integer parameter: " + token);
                    continue;
                }

                if (nameValue[0].equals("id")) {
                    networkId = value;
                } else if (nameValue[0].equals("state")) {
                    newState = value;
                }
            }

            if (newState == -1) return;

            SupplicantState newSupplicantState = SupplicantState.INVALID;
            for (SupplicantState state : SupplicantState.values()) {
                if (state.ordinal() == newState) {
                    newSupplicantState = state;
                    break;
                }
            }
            if (newSupplicantState == SupplicantState.INVALID) {
                Log.w(TAG, "Invalid supplicant state: " + newState);
            }
            mWifiStateTracker.notifyStateChange(networkId, BSSID, newSupplicantState);
        }
    }

    private void handleNetworkStateChange(NetworkInfo.DetailedState newState, String data) {
        String BSSID = null;
        int networkId = -1;
        if (newState == NetworkInfo.DetailedState.CONNECTED) {
            Matcher match = mConnectedEventPattern.matcher(data);
            if (!match.find()) {
                if (Config.LOGD) Log.d(TAG, "Could not find BSSID in CONNECTED event string");
            } else {
                BSSID = match.group(1);
                try {
                    networkId = Integer.parseInt(match.group(2));
                } catch (NumberFormatException e) {
                    networkId = -1;
                }
            }
        }
        mWifiStateTracker.notifyStateChange(newState, BSSID, networkId);
    }

    /**
     * Sleep for a period of time.
     * @param secs the number of seconds to sleep
     */
    private static void nap(int secs) {
        try {
            Thread.sleep(secs * 1000);
        } catch (InterruptedException ignore) {
        }
    }
}