/*
* Copyright (C) 2014 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.Manifest.permission;
import android.content.Context;
import android.net.INetworkScoreCache;
import android.net.NetworkKey;
import android.net.ScoredNetwork;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.util.Log;
import java.io.FileDescriptor;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class WifiNetworkScoreCache extends INetworkScoreCache.Stub
{
// A Network scorer returns a score in the range [-128, +127]
// We treat the lowest possible score as though there were no score, effectively allowing the
// scorer to provide an RSSI threshold below which a network should not be used.
public static int INVALID_NETWORK_SCORE = Byte.MIN_VALUE;
private static String TAG = "WifiNetworkScoreCache";
private boolean DBG = true;
private final Context mContext;
// The key is of the form "<ssid>"<bssid>
// TODO: What about SSIDs that can't be encoded as UTF-8?
private final Map<String, ScoredNetwork> mNetworkCache;
public WifiNetworkScoreCache(Context context) {
mContext = context;
mNetworkCache = new HashMap<String, ScoredNetwork>();
}
@Override public final void updateScores(List<android.net.ScoredNetwork> networks) {
if (networks == null) {
return;
}
Log.e(TAG, "updateScores list size=" + networks.size());
synchronized(mNetworkCache) {
for (ScoredNetwork network : networks) {
String networkKey = buildNetworkKey(network);
if (networkKey == null) continue;
mNetworkCache.put(networkKey, network);
}
}
}
@Override public final void clearScores() {
synchronized (mNetworkCache) {
mNetworkCache.clear();
}
}
/**
* Returns whether there is any score info for the given ScanResult.
*
* This includes null-score info, so it should only be used when determining whether to request
* scores from the network scorer.
*/
public boolean isScoredNetwork(ScanResult result) {
return getScoredNetwork(result) != null;
}
/**
* Returns whether there is a non-null score curve for the given ScanResult.
*
* A null score curve has special meaning - we should never connect to an ephemeral network if
* the score curve is null.
*/
public boolean hasScoreCurve(ScanResult result) {
ScoredNetwork network = getScoredNetwork(result);
return network != null && network.rssiCurve != null;
}
public int getNetworkScore(ScanResult result) {
int score = INVALID_NETWORK_SCORE;
ScoredNetwork network = getScoredNetwork(result);
if (network != null && network.rssiCurve != null) {
score = network.rssiCurve.lookupScore(result.level);
if (DBG) {
Log.e(TAG, "getNetworkScore found scored network " + network.networkKey
+ " score " + Integer.toString(score)
+ " RSSI " + result.level);
}
}
return score;
}
public int getNetworkScore(ScanResult result, boolean isActiveNetwork) {
int score = INVALID_NETWORK_SCORE;
ScoredNetwork network = getScoredNetwork(result);
if (network != null && network.rssiCurve != null) {
score = network.rssiCurve.lookupScore(result.level, isActiveNetwork);
if (DBG) {
Log.e(TAG, "getNetworkScore found scored network " + network.networkKey
+ " score " + Integer.toString(score)
+ " RSSI " + result.level
+ " isActiveNetwork " + isActiveNetwork);
}
}
return score;
}
private ScoredNetwork getScoredNetwork(ScanResult result) {
String key = buildNetworkKey(result);
if (key == null) return null;
//find it
synchronized(mNetworkCache) {
ScoredNetwork network = mNetworkCache.get(key);
return network;
}
}
private String buildNetworkKey(ScoredNetwork network) {
if (network == null || network.networkKey == null) return null;
if (network.networkKey.wifiKey == null) return null;
if (network.networkKey.type == NetworkKey.TYPE_WIFI) {
String key = network.networkKey.wifiKey.ssid;
if (key == null) return null;
if (network.networkKey.wifiKey.bssid != null) {
key = key + network.networkKey.wifiKey.bssid;
}
return key;
}
return null;
}
private String buildNetworkKey(ScanResult result) {
if (result == null || result.SSID == null) {
return null;
}
StringBuilder key = new StringBuilder("\"");
key.append(result.SSID);
key.append("\"");
if (result.BSSID != null) {
key.append(result.BSSID);
}
return key.toString();
}
@Override protected final void dump(FileDescriptor fd, PrintWriter writer, String[] args) {
mContext.enforceCallingOrSelfPermission(permission.DUMP, TAG);
writer.println("WifiNetworkScoreCache");
writer.println(" All score curves:");
for (Map.Entry<String, ScoredNetwork> entry : mNetworkCache.entrySet()) {
writer.println(" " + entry.getKey() + ": " + entry.getValue().rssiCurve);
}
writer.println(" Current network scores:");
WifiManager wifiManager = (WifiManager) mContext.getSystemService(Context.WIFI_SERVICE);
for (ScanResult scanResult : wifiManager.getScanResults()) {
writer.println(" " + buildNetworkKey(scanResult) + ": " + getNetworkScore(scanResult));
}
}
}