service/java/com/android/server/wifi/ScanDetailCache.java - platform/frameworks/opt/net/wifi - Git at Google

 /*
  * Copyright (C) 2015 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 com.android.server.wifi;

 import android.net.wifi.ScanResult;
 import android.net.wifi.WifiConfiguration;
 import android.os.SystemClock;
 import android.util.Log;

 import com.android.server.wifi.hotspot2.PasspointMatch;
 import com.android.server.wifi.hotspot2.PasspointMatchInfo;
 import com.android.server.wifi.hotspot2.pps.HomeSP;

 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.Iterator;
 import java.util.concurrent.ConcurrentHashMap;

 /**
  * Maps BSSIDs to their individual ScanDetails for a given WifiConfiguration.
  */
 public class ScanDetailCache {

     private static final String TAG = "ScanDetailCache";
     private static final boolean DBG = false;

     private WifiConfiguration mConfig;
     private ConcurrentHashMap<String, ScanDetail> mMap;
     private ConcurrentHashMap<String, PasspointMatchInfo> mPasspointMatches;

     ScanDetailCache(WifiConfiguration config) {
         mConfig = config;
         mMap = new ConcurrentHashMap(16, 0.75f, 2);
         mPasspointMatches = new ConcurrentHashMap(16, 0.75f, 2);
     }

     void put(ScanDetail scanDetail) {
         put(scanDetail, null, null);
     }

     void put(ScanDetail scanDetail, PasspointMatch match, HomeSP homeSp) {

         mMap.put(scanDetail.getBSSIDString(), scanDetail);

         if (match != null && homeSp != null) {
             mPasspointMatches.put(scanDetail.getBSSIDString(),
                     new PasspointMatchInfo(match, scanDetail, homeSp));
         }
     }

     ScanResult get(String bssid) {
         ScanDetail scanDetail = getScanDetail(bssid);
         return scanDetail == null ? null : scanDetail.getScanResult();
     }

     ScanDetail getScanDetail(String bssid) {
         return mMap.get(bssid);
     }

     void remove(String bssid) {
         mMap.remove(bssid);
     }

     int size() {
         return mMap.size();
     }

     boolean isEmpty() {
         return size() == 0;
     }

     Collection<String> keySet() {
         return mMap.keySet();
     }

     Collection<ScanDetail> values() {
         return mMap.values();
     }

     /**
      * Method to reduce the cache to the given size by removing the oldest entries.
      *
      * @param num int target cache size
      */
     public void trim(int num) {
         int currentSize = mMap.size();
         if (currentSize <= num) {
             return; // Nothing to trim
         }
         ArrayList<ScanDetail> list = new ArrayList<ScanDetail>(mMap.values());
         if (list.size() != 0) {
             // Sort by descending timestamp
             Collections.sort(list, new Comparator() {
                 public int compare(Object o1, Object o2) {
                     ScanDetail a = (ScanDetail) o1;
                     ScanDetail b = (ScanDetail) o2;
                     if (a.getSeen() > b.getSeen()) {
                         return 1;
                     }
                     if (a.getSeen() < b.getSeen()) {
                         return -1;
                     }
                     return a.getBSSIDString().compareTo(b.getBSSIDString());
                 }
             });
         }
         for (int i = 0; i < currentSize - num; i++) {
             // Remove oldest results from scan cache
             ScanDetail result = list.get(i);
             mMap.remove(result.getBSSIDString());
             mPasspointMatches.remove(result.getBSSIDString());
         }
     }

     /* @hide */
     private ArrayList<ScanDetail> sort() {
         ArrayList<ScanDetail> list = new ArrayList<ScanDetail>(mMap.values());
         if (list.size() != 0) {
             Collections.sort(list, new Comparator() {
                 public int compare(Object o1, Object o2) {
                     ScanResult a = ((ScanDetail) o1).getScanResult();
                     ScanResult b = ((ScanDetail) o2).getScanResult();
                     if (a.numIpConfigFailures > b.numIpConfigFailures) {
                         return 1;
                     }
                     if (a.numIpConfigFailures < b.numIpConfigFailures) {
                         return -1;
                     }
                     if (a.seen > b.seen) {
                         return -1;
                     }
                     if (a.seen < b.seen) {
                         return 1;
                     }
                     if (a.level > b.level) {
                         return -1;
                     }
                     if (a.level < b.level) {
                         return 1;
                     }
                     return a.BSSID.compareTo(b.BSSID);
                 }
             });
         }
         return list;
     }

     /**
      * Method to get cached scan results that are less than 'age' old.
      *
      * @param age long Time window of desired results.
      * @return WifiConfiguration.Visibility matches in the given visibility
      */
     public WifiConfiguration.Visibility getVisibilityByRssi(long age) {
         WifiConfiguration.Visibility status = new WifiConfiguration.Visibility();

         long now_ms = System.currentTimeMillis();
         long now_elapsed_ms = SystemClock.elapsedRealtime();
         for (ScanDetail scanDetail : values()) {
             ScanResult result = scanDetail.getScanResult();
             if (scanDetail.getSeen() == 0) {
                 continue;
             }

             if (result.is5GHz()) {
                 //strictly speaking: [4915, 5825]
                 //number of known BSSID on 5GHz band
                 status.num5 = status.num5 + 1;
             } else if (result.is24GHz()) {
                 //strictly speaking: [2412, 2482]
                 //number of known BSSID on 2.4Ghz band
                 status.num24 = status.num24 + 1;
             }

             if (result.timestamp != 0) {
                 if (DBG) {
                     Log.e("getVisibilityByRssi", " considering " + result.SSID + " " + result.BSSID
                             + " elapsed=" + now_elapsed_ms + " timestamp=" + result.timestamp
                             + " age = " + age);
                 }
                 if ((now_elapsed_ms - (result.timestamp / 1000)) > age) continue;
             } else {
                 // This checks the time at which we have received the scan result from supplicant
                 if ((now_ms - result.seen) > age) continue;
             }

             if (result.is5GHz()) {
                 if (result.level > status.rssi5) {
                     status.rssi5 = result.level;
                     status.age5 = result.seen;
                     status.BSSID5 = result.BSSID;
                 }
             } else if (result.is24GHz()) {
                 if (result.level > status.rssi24) {
                     status.rssi24 = result.level;
                     status.age24 = result.seen;
                     status.BSSID24 = result.BSSID;
                 }
             }
         }

         return status;
     }

     /**
      * Method returning the Visibility based on passpoint match time.
      *
      * @param age long Desired time window for matches.
      * @return WifiConfiguration.Visibility matches in the given visibility
      */
     public WifiConfiguration.Visibility getVisibilityByPasspointMatch(long age) {

         long now_ms = System.currentTimeMillis();
         PasspointMatchInfo pmiBest24 = null, pmiBest5 = null;

         for (PasspointMatchInfo pmi : mPasspointMatches.values()) {
             ScanDetail scanDetail = pmi.getScanDetail();
             if (scanDetail == null) continue;
             ScanResult result = scanDetail.getScanResult();
             if (result == null) continue;

             if (scanDetail.getSeen() == 0) continue;

             if ((now_ms - result.seen) > age) continue;

             if (result.is5GHz()) {
                 if (pmiBest5 == null || pmiBest5.compareTo(pmi) < 0) {
                     pmiBest5 = pmi;
                 }
             } else if (result.is24GHz()) {
                 if (pmiBest24 == null || pmiBest24.compareTo(pmi) < 0) {
                     pmiBest24 = pmi;
                 }
             }
         }

         WifiConfiguration.Visibility status = new WifiConfiguration.Visibility();
         String logMsg = "Visiblity by passpoint match returned ";
         if (pmiBest5 != null) {
             ScanResult result = pmiBest5.getScanDetail().getScanResult();
             status.rssi5 = result.level;
             status.age5 = result.seen;
             status.BSSID5 = result.BSSID;
             logMsg += "5 GHz BSSID of " + result.BSSID;
         }
         if (pmiBest24 != null) {
             ScanResult result = pmiBest24.getScanDetail().getScanResult();
             status.rssi24 = result.level;
             status.age24 = result.seen;
             status.BSSID24 = result.BSSID;
             logMsg += "2.4 GHz BSSID of " + result.BSSID;
         }

         Log.d(TAG, logMsg);

         return status;
     }

     /**
      * Method to get scan matches for the desired time window.  Returns matches by passpoint time if
      * the WifiConfiguration is passpoint.
      *
      * @param age long desired time for matches.
      * @return WifiConfiguration.Visibility matches in the given visibility
      */
     public WifiConfiguration.Visibility getVisibility(long age) {
         if (mConfig.isPasspoint()) {
             return getVisibilityByPasspointMatch(age);
         } else {
             return getVisibilityByRssi(age);
         }
     }


     @Override
     public String toString() {
         StringBuilder sbuf = new StringBuilder();
         sbuf.append("Scan Cache:  ").append('\n');

         ArrayList<ScanDetail> list = sort();
         long now_ms = System.currentTimeMillis();
         if (list.size() > 0) {
             for (ScanDetail scanDetail : list) {
                 ScanResult result = scanDetail.getScanResult();
                 long milli = now_ms - scanDetail.getSeen();
                 long ageSec = 0;
                 long ageMin = 0;
                 long ageHour = 0;
                 long ageMilli = 0;
                 long ageDay = 0;
                 if (now_ms > scanDetail.getSeen() && scanDetail.getSeen() > 0) {
                     ageMilli = milli % 1000;
                     ageSec   = (milli / 1000) % 60;
                     ageMin   = (milli / (60 * 1000)) % 60;
                     ageHour  = (milli / (60 * 60 * 1000)) % 24;
                     ageDay   = (milli / (24 * 60 * 60 * 1000));
                 }
                 sbuf.append("{").append(result.BSSID).append(",").append(result.frequency);
                 sbuf.append(",").append(String.format("%3d", result.level));
                 if (ageSec > 0 || ageMilli > 0) {
                     sbuf.append(String.format(",%4d.%02d.%02d.%02d.%03dms", ageDay,
                             ageHour, ageMin, ageSec, ageMilli));
                 }
                 if (result.numIpConfigFailures > 0) {
                     sbuf.append(",ipfail=");
                     sbuf.append(result.numIpConfigFailures);
                 }
                 sbuf.append("} ");
             }
             sbuf.append('\n');
         }

         return sbuf.toString();
     }

 }
	/*
	* Copyright (C) 2015 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 com.android.server.wifi;

	import android.net.wifi.ScanResult;
	import android.net.wifi.WifiConfiguration;
	import android.os.SystemClock;
	import android.util.Log;

	import com.android.server.wifi.hotspot2.PasspointMatch;
	import com.android.server.wifi.hotspot2.PasspointMatchInfo;
	import com.android.server.wifi.hotspot2.pps.HomeSP;

	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.Comparator;
	import java.util.Iterator;
	import java.util.concurrent.ConcurrentHashMap;

	/**
	* Maps BSSIDs to their individual ScanDetails for a given WifiConfiguration.
	*/
	public class ScanDetailCache {

	private static final String TAG = "ScanDetailCache";
	private static final boolean DBG = false;

	private WifiConfiguration mConfig;
	private ConcurrentHashMap<String, ScanDetail> mMap;
	private ConcurrentHashMap<String, PasspointMatchInfo> mPasspointMatches;

	ScanDetailCache(WifiConfiguration config) {
	mConfig = config;
	mMap = new ConcurrentHashMap(16, 0.75f, 2);
	mPasspointMatches = new ConcurrentHashMap(16, 0.75f, 2);
	}

	void put(ScanDetail scanDetail) {
	put(scanDetail, null, null);
	}

	void put(ScanDetail scanDetail, PasspointMatch match, HomeSP homeSp) {

	mMap.put(scanDetail.getBSSIDString(), scanDetail);

	if (match != null && homeSp != null) {
	mPasspointMatches.put(scanDetail.getBSSIDString(),
	new PasspointMatchInfo(match, scanDetail, homeSp));
	}
	}

	ScanResult get(String bssid) {
	ScanDetail scanDetail = getScanDetail(bssid);
	return scanDetail == null ? null : scanDetail.getScanResult();
	}

	ScanDetail getScanDetail(String bssid) {
	return mMap.get(bssid);
	}

	void remove(String bssid) {
	mMap.remove(bssid);
	}

	int size() {
	return mMap.size();
	}

	boolean isEmpty() {
	return size() == 0;
	}

	Collection<String> keySet() {
	return mMap.keySet();
	}

	Collection<ScanDetail> values() {
	return mMap.values();
	}

	/**
	* Method to reduce the cache to the given size by removing the oldest entries.
	*
	* @param num int target cache size
	*/
	public void trim(int num) {
	int currentSize = mMap.size();
	if (currentSize <= num) {
	return; // Nothing to trim
	}
	ArrayList<ScanDetail> list = new ArrayList<ScanDetail>(mMap.values());
	if (list.size() != 0) {
	// Sort by descending timestamp
	Collections.sort(list, new Comparator() {
	public int compare(Object o1, Object o2) {
	ScanDetail a = (ScanDetail) o1;
	ScanDetail b = (ScanDetail) o2;
	if (a.getSeen() > b.getSeen()) {
	return 1;
	}
	if (a.getSeen() < b.getSeen()) {
	return -1;
	}
	return a.getBSSIDString().compareTo(b.getBSSIDString());
	}
	});
	}
	for (int i = 0; i < currentSize - num; i++) {
	// Remove oldest results from scan cache
	ScanDetail result = list.get(i);
	mMap.remove(result.getBSSIDString());
	mPasspointMatches.remove(result.getBSSIDString());
	}
	}

	/* @hide */
	private ArrayList<ScanDetail> sort() {
	ArrayList<ScanDetail> list = new ArrayList<ScanDetail>(mMap.values());
	if (list.size() != 0) {
	Collections.sort(list, new Comparator() {
	public int compare(Object o1, Object o2) {
	ScanResult a = ((ScanDetail) o1).getScanResult();
	ScanResult b = ((ScanDetail) o2).getScanResult();
	if (a.numIpConfigFailures > b.numIpConfigFailures) {
	return 1;
	}
	if (a.numIpConfigFailures < b.numIpConfigFailures) {
	return -1;
	}
	if (a.seen > b.seen) {
	return -1;
	}
	if (a.seen < b.seen) {
	return 1;
	}
	if (a.level > b.level) {
	return -1;
	}
	if (a.level < b.level) {
	return 1;
	}
	return a.BSSID.compareTo(b.BSSID);
	}
	});
	}
	return list;
	}

	/**
	* Method to get cached scan results that are less than 'age' old.
	*
	* @param age long Time window of desired results.
	* @return WifiConfiguration.Visibility matches in the given visibility
	*/
	public WifiConfiguration.Visibility getVisibilityByRssi(long age) {
	WifiConfiguration.Visibility status = new WifiConfiguration.Visibility();

	long now_ms = System.currentTimeMillis();
	long now_elapsed_ms = SystemClock.elapsedRealtime();
	for (ScanDetail scanDetail : values()) {
	ScanResult result = scanDetail.getScanResult();
	if (scanDetail.getSeen() == 0) {
	continue;
	}

	if (result.is5GHz()) {
	//strictly speaking: [4915, 5825]
	//number of known BSSID on 5GHz band
	status.num5 = status.num5 + 1;
	} else if (result.is24GHz()) {
	//strictly speaking: [2412, 2482]
	//number of known BSSID on 2.4Ghz band
	status.num24 = status.num24 + 1;
	}

	if (result.timestamp != 0) {
	if (DBG) {
	Log.e("getVisibilityByRssi", " considering " + result.SSID + " " + result.BSSID
	+ " elapsed=" + now_elapsed_ms + " timestamp=" + result.timestamp
	+ " age = " + age);
	}
	if ((now_elapsed_ms - (result.timestamp / 1000)) > age) continue;
	} else {
	// This checks the time at which we have received the scan result from supplicant
	if ((now_ms - result.seen) > age) continue;
	}

	if (result.is5GHz()) {
	if (result.level > status.rssi5) {
	status.rssi5 = result.level;
	status.age5 = result.seen;
	status.BSSID5 = result.BSSID;
	}
	} else if (result.is24GHz()) {
	if (result.level > status.rssi24) {
	status.rssi24 = result.level;
	status.age24 = result.seen;
	status.BSSID24 = result.BSSID;
	}
	}
	}

	return status;
	}

	/**
	* Method returning the Visibility based on passpoint match time.
	*
	* @param age long Desired time window for matches.
	* @return WifiConfiguration.Visibility matches in the given visibility
	*/
	public WifiConfiguration.Visibility getVisibilityByPasspointMatch(long age) {

	long now_ms = System.currentTimeMillis();
	PasspointMatchInfo pmiBest24 = null, pmiBest5 = null;

	for (PasspointMatchInfo pmi : mPasspointMatches.values()) {
	ScanDetail scanDetail = pmi.getScanDetail();
	if (scanDetail == null) continue;
	ScanResult result = scanDetail.getScanResult();
	if (result == null) continue;

	if (scanDetail.getSeen() == 0) continue;

	if ((now_ms - result.seen) > age) continue;

	if (result.is5GHz()) {
	if (pmiBest5 == null \|\| pmiBest5.compareTo(pmi) < 0) {
	pmiBest5 = pmi;
	}
	} else if (result.is24GHz()) {
	if (pmiBest24 == null \|\| pmiBest24.compareTo(pmi) < 0) {
	pmiBest24 = pmi;
	}
	}
	}

	WifiConfiguration.Visibility status = new WifiConfiguration.Visibility();
	String logMsg = "Visiblity by passpoint match returned ";
	if (pmiBest5 != null) {
	ScanResult result = pmiBest5.getScanDetail().getScanResult();
	status.rssi5 = result.level;
	status.age5 = result.seen;
	status.BSSID5 = result.BSSID;
	logMsg += "5 GHz BSSID of " + result.BSSID;
	}
	if (pmiBest24 != null) {
	ScanResult result = pmiBest24.getScanDetail().getScanResult();
	status.rssi24 = result.level;
	status.age24 = result.seen;
	status.BSSID24 = result.BSSID;
	logMsg += "2.4 GHz BSSID of " + result.BSSID;
	}

	Log.d(TAG, logMsg);

	return status;
	}

	/**
	* Method to get scan matches for the desired time window. Returns matches by passpoint time if
	* the WifiConfiguration is passpoint.
	*
	* @param age long desired time for matches.
	* @return WifiConfiguration.Visibility matches in the given visibility
	*/
	public WifiConfiguration.Visibility getVisibility(long age) {
	if (mConfig.isPasspoint()) {
	return getVisibilityByPasspointMatch(age);
	} else {
	return getVisibilityByRssi(age);
	}
	}



	@Override
	public String toString() {
	StringBuilder sbuf = new StringBuilder();
	sbuf.append("Scan Cache: ").append('\n');

	ArrayList<ScanDetail> list = sort();
	long now_ms = System.currentTimeMillis();
	if (list.size() > 0) {
	for (ScanDetail scanDetail : list) {
	ScanResult result = scanDetail.getScanResult();
	long milli = now_ms - scanDetail.getSeen();
	long ageSec = 0;
	long ageMin = 0;
	long ageHour = 0;
	long ageMilli = 0;
	long ageDay = 0;
	if (now_ms > scanDetail.getSeen() && scanDetail.getSeen() > 0) {
	ageMilli = milli % 1000;
	ageSec = (milli / 1000) % 60;
	ageMin = (milli / (60 * 1000)) % 60;
	ageHour = (milli / (60 * 60 * 1000)) % 24;
	ageDay = (milli / (24 * 60 * 60 * 1000));
	}
	sbuf.append("{").append(result.BSSID).append(",").append(result.frequency);
	sbuf.append(",").append(String.format("%3d", result.level));
	if (ageSec > 0 \|\| ageMilli > 0) {
	sbuf.append(String.format(",%4d.%02d.%02d.%02d.%03dms", ageDay,
	ageHour, ageMin, ageSec, ageMilli));
	}
	if (result.numIpConfigFailures > 0) {
	sbuf.append(",ipfail=");
	sbuf.append(result.numIpConfigFailures);
	}
	sbuf.append("} ");
	}
	sbuf.append('\n');
	}

	return sbuf.toString();
	}

	}