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Enhancements for avoiding poor connection on wifi

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- Avoid flapping
- Increase thresholds and monitor rssi more closely to detect consistently weak signal

Change-Id: I6139a20b7306839b345146a72ce690020a2e00b8
This commit is contained in:
Irfan Sheriff
2012-03-08 16:11:02 -08:00
parent b7fdddab0d
commit 4c8982ad82
3 changed files with 161 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
core/java/android/provider/Settings.java
View File

@@ -3128,6 +3128,14 @@ public final class Settings {
public static final String WIFI_WATCHDOG_ARP_CHECK_INTERVAL_MS =
"wifi_watchdog_arp_interval_ms";
/**
* ms delay interval between rssi polling when the signal is known to be weak
* @hide
*/
public static final String WIFI_WATCHDOG_RSSI_FETCH_INTERVAL_MS =
"wifi_watchdog_rssi_fetch_interval_ms";
/**
* ms delay before rechecking a connect SSID for walled garden with a http download.
* @hide

9
wifi/java/android/net/wifi/WifiStateMachine.java
View File

@@ -1852,6 +1852,9 @@ public class WifiStateMachine extends StateMachine {
replyToMessage(message, WifiManager.DISABLE_NETWORK_FAILED,
WifiManager.BUSY);
break;
case WifiWatchdogStateMachine.RSSI_FETCH:
replyToMessage(message, WifiWatchdogStateMachine.RSSI_FETCH_FAILED);
break;
default:
loge("Error! unhandled message" + message);
break;
@@ -2998,6 +3001,12 @@ public class WifiStateMachine extends StateMachine {
mRssiPollToken, 0), POLL_RSSI_INTERVAL_MSECS);
}
break;
case WifiWatchdogStateMachine.RSSI_FETCH:
eventLoggingEnabled = false;
fetchRssiAndLinkSpeedNative();
replyToMessage(message, WifiWatchdogStateMachine.RSSI_FETCH_SUCCEEDED,
mWifiInfo.getRssi());
break;
default:
return NOT_HANDLED;
}

186
wifi/java/android/net/wifi/WifiWatchdogStateMachine.java
View File

@@ -93,17 +93,36 @@ public class WifiWatchdogStateMachine extends StateMachine {
private static final String TAG = "WifiWatchdogStateMachine";
private static final String WALLED_GARDEN_NOTIFICATION_ID = "WifiWatchdog.walledgarden";
/* RSSI Levels as used by notification icon
Level 4 -55 <= RSSI
Level 3 -66 <= RSSI < -55
Level 2 -77 <= RSSI < -67
Level 1 -88 <= RSSI < -78
Level 0 RSSI < -88 */
/* Wi-fi connection is considered poor below this
RSSI level threshold and the watchdog report it
to the WifiStateMachine */
private static final int RSSI_LEVEL_CUTOFF = 1;
private static final int RSSI_LEVEL_CUTOFF = 0;
/* Wi-fi connection is monitored actively below this
threshold */
private static final int RSSI_LEVEL_MONITOR = 2;
private static final int RSSI_LEVEL_MONITOR = 1;
/* RSSI threshold during monitoring below which network is avoided */
private static final int RSSI_MONITOR_THRESHOLD = -84;
/* Number of times RSSI is measured to be low before being avoided */
private static final int RSSI_MONITOR_COUNT = 5;
private int mRssiMonitorCount = 0;
/* Avoid flapping */
private static final int MIN_INTERVAL_AVOID_BSSID_MS = 60 * 1000;
private String mLastAvoidedBssid;
/* a -ve interval to allow avoidance at boot */
private long mLastBssidAvoidedTime = -MIN_INTERVAL_AVOID_BSSID_MS;
private int mCurrentSignalLevel;
private static final long DEFAULT_ARP_CHECK_INTERVAL_MS = 2 * 60 * 1000;
private static final long DEFAULT_RSSI_FETCH_INTERVAL_MS = 1000;
private static final long DEFAULT_WALLED_GARDEN_INTERVAL_MS = 30 * 60 * 1000;
private static final int DEFAULT_NUM_ARP_PINGS = 5;
@@ -143,10 +162,14 @@ public class WifiWatchdogStateMachine extends StateMachine {
/* Internal messages */
private static final int CMD_ARP_CHECK = BASE + 11;
private static final int CMD_DELAYED_WALLED_GARDEN_CHECK = BASE + 12;
private static final int CMD_RSSI_FETCH = BASE + 13;
/* Notifications to WifiStateMachine */
static final int POOR_LINK_DETECTED = BASE + 21;
static final int GOOD_LINK_DETECTED = BASE + 22;
static final int RSSI_FETCH = BASE + 23;
static final int RSSI_FETCH_SUCCEEDED = BASE + 24;
static final int RSSI_FETCH_FAILED = BASE + 25;
private static final int SINGLE_ARP_CHECK = 0;
private static final int FULL_ARP_CHECK = 1;
@@ -167,11 +190,15 @@ public class WifiWatchdogStateMachine extends StateMachine {
private WalledGardenCheckState mWalledGardenCheckState = new WalledGardenCheckState();
/* Online and watching link connectivity */
private OnlineWatchState mOnlineWatchState = new OnlineWatchState();
/* RSSI level is at RSSI_LEVEL_MONITOR and needs close monitoring */
private RssiMonitoringState mRssiMonitoringState = new RssiMonitoringState();
/* Online and doing nothing */
private OnlineState mOnlineState = new OnlineState();
private int mArpToken = 0;
private long mArpCheckIntervalMs;
private int mRssiFetchToken = 0;
private long mRssiFetchIntervalMs;
private long mWalledGardenIntervalMs;
private int mNumArpPings;
private int mMinArpResponses;
@@ -219,6 +246,7 @@ public class WifiWatchdogStateMachine extends StateMachine {
addState(mConnectedState, mWatchdogEnabledState);
addState(mWalledGardenCheckState, mConnectedState);
addState(mOnlineWatchState, mConnectedState);
addState(mRssiMonitoringState, mOnlineWatchState);
addState(mOnlineState, mConnectedState);
if (isWatchdogEnabled()) {
@@ -239,6 +267,7 @@ public class WifiWatchdogStateMachine extends StateMachine {
// Disable for wifi only devices.
if (Settings.Secure.getString(contentResolver, Settings.Secure.WIFI_WATCHDOG_ON) == null
&& sWifiOnly) {
log("Disabling watchog for wi-fi only device");
putSettingsBoolean(contentResolver, Settings.Secure.WIFI_WATCHDOG_ON, false);
}
WifiWatchdogStateMachine wwsm = new WifiWatchdogStateMachine(context);
@@ -361,6 +390,7 @@ public class WifiWatchdogStateMachine extends StateMachine {
pw.println("mLinkProperties: [" + mLinkProperties + "]");
pw.println("mCurrentSignalLevel: [" + mCurrentSignalLevel + "]");
pw.println("mArpCheckIntervalMs: [" + mArpCheckIntervalMs+ "]");
pw.println("mRssiFetchIntervalMs: [" + mRssiFetchIntervalMs + "]");
pw.println("mWalledGardenIntervalMs: [" + mWalledGardenIntervalMs + "]");
pw.println("mNumArpPings: [" + mNumArpPings + "]");
pw.println("mMinArpResponses: [" + mMinArpResponses + "]");
@@ -371,7 +401,9 @@ public class WifiWatchdogStateMachine extends StateMachine {
}
private boolean isWatchdogEnabled() {
return getSettingsBoolean(mContentResolver, Settings.Secure.WIFI_WATCHDOG_ON, true);
boolean ret = getSettingsBoolean(mContentResolver, Settings.Secure.WIFI_WATCHDOG_ON, true);
if (DBG) log("watchdog enabled " + ret);
return ret;
}
private void updateSettings() {
@@ -380,6 +412,9 @@ public class WifiWatchdogStateMachine extends StateMachine {
mArpCheckIntervalMs = Secure.getLong(mContentResolver,
Secure.WIFI_WATCHDOG_ARP_CHECK_INTERVAL_MS,
DEFAULT_ARP_CHECK_INTERVAL_MS);
mRssiFetchIntervalMs = Secure.getLong(mContentResolver,
Secure.WIFI_WATCHDOG_RSSI_FETCH_INTERVAL_MS,
DEFAULT_RSSI_FETCH_INTERVAL_MS);
mNumArpPings = Secure.getInt(mContentResolver,
Secure.WIFI_WATCHDOG_NUM_ARP_PINGS,
DEFAULT_NUM_ARP_PINGS);
@@ -435,6 +470,11 @@ public class WifiWatchdogStateMachine extends StateMachine {
}
class DefaultState extends State {
@Override
public void enter() {
if (DBG) log(getName() + "\n");
}
@Override
public boolean processMessage(Message msg) {
switch (msg.what) {
@@ -445,13 +485,15 @@ public class WifiWatchdogStateMachine extends StateMachine {
}
break;
case EVENT_RSSI_CHANGE:
mCurrentSignalLevel = WifiManager.calculateSignalLevel(msg.arg1,
WifiManager.RSSI_LEVELS);
mCurrentSignalLevel = calculateSignalLevel(msg.arg1);
break;
case EVENT_WIFI_RADIO_STATE_CHANGE:
case EVENT_NETWORK_STATE_CHANGE:
case CMD_ARP_CHECK:
case CMD_DELAYED_WALLED_GARDEN_CHECK:
case CMD_RSSI_FETCH:
case RSSI_FETCH_SUCCEEDED:
case RSSI_FETCH_FAILED:
//ignore
break;
default:
@@ -463,6 +505,11 @@ public class WifiWatchdogStateMachine extends StateMachine {
}
class WatchdogDisabledState extends State {
@Override
public void enter() {
if (DBG) log(getName() + "\n");
}
@Override
public boolean processMessage(Message msg) {
switch (msg.what) {
@@ -493,7 +540,7 @@ public class WifiWatchdogStateMachine extends StateMachine {
@Override
public void enter() {
if (DBG) log("WifiWatchdogService enabled");
}
}
@Override
public boolean processMessage(Message msg) {
@@ -507,6 +554,8 @@ public class WifiWatchdogStateMachine extends StateMachine {
NetworkInfo networkInfo = (NetworkInfo)
intent.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
if (DBG) log("network state change " + networkInfo.getDetailedState());
switch (networkInfo.getDetailedState()) {
case VERIFYING_POOR_LINK:
mLinkProperties = (LinkProperties) intent.getParcelableExtra(
@@ -557,6 +606,10 @@ public class WifiWatchdogStateMachine extends StateMachine {
}
class NotConnectedState extends State {
@Override
public void enter() {
if (DBG) log(getName() + "\n");
}
}
class VerifyingLinkState extends State {
@@ -568,7 +621,7 @@ public class WifiWatchdogStateMachine extends StateMachine {
}
private void handleRssiChange() {
if (mCurrentSignalLevel <= RSSI_LEVEL_CUTOFF) {
if (mCurrentSignalLevel <= RSSI_LEVEL_MONITOR) {
//stay here
if (DBG) log("enter VerifyingLinkState, stay level: " + mCurrentSignalLevel);
} else {
@@ -587,11 +640,7 @@ public class WifiWatchdogStateMachine extends StateMachine {
}
break;
case EVENT_RSSI_CHANGE:
int signalLevel = WifiManager.calculateSignalLevel(msg.arg1,
WifiManager.RSSI_LEVELS);
if (DBG) log("RSSI change old: " + mCurrentSignalLevel + "new: " + signalLevel);
mCurrentSignalLevel = signalLevel;
mCurrentSignalLevel = calculateSignalLevel(msg.arg1);
handleRssiChange();
break;
case CMD_ARP_CHECK:
@@ -680,11 +729,11 @@ public class WifiWatchdogStateMachine extends StateMachine {
private void handleRssiChange() {
if (mCurrentSignalLevel <= RSSI_LEVEL_CUTOFF) {
if (DBG) log("Transition out, below cut off level: " + mCurrentSignalLevel);
mWsmChannel.sendMessage(POOR_LINK_DETECTED);
sendPoorLinkDetected();
} else if (mCurrentSignalLevel <= RSSI_LEVEL_MONITOR) {
if (DBG) log("Start monitoring, level: " + mCurrentSignalLevel);
sendMessage(obtainMessage(CMD_ARP_CHECK, ++mArpToken, 0));
transitionTo(mRssiMonitoringState);
} else {
//stay here
}
}
@@ -692,30 +741,14 @@ public class WifiWatchdogStateMachine extends StateMachine {
public boolean processMessage(Message msg) {
switch (msg.what) {
case EVENT_RSSI_CHANGE:
int signalLevel = WifiManager.calculateSignalLevel(msg.arg1,
WifiManager.RSSI_LEVELS);
if (DBG) log("RSSI change old: " + mCurrentSignalLevel + "new: " + signalLevel);
mCurrentSignalLevel = signalLevel;
handleRssiChange();
break;
case CMD_ARP_CHECK:
if (msg.arg1 == mArpToken) {
if (doArpTest(SINGLE_ARP_CHECK) != true) {
if (DBG) log("single ARP fail, full ARP check");
//do a full test
if (doArpTest(FULL_ARP_CHECK) != true) {
if (DBG) log("notify full ARP fail, level: " + mCurrentSignalLevel);
mWsmChannel.sendMessage(POOR_LINK_DETECTED);
}
}
if (mCurrentSignalLevel <= RSSI_LEVEL_MONITOR) {
if (DBG) log("Continue ARP check, rssi level: " + mCurrentSignalLevel);
sendMessageDelayed(obtainMessage(CMD_ARP_CHECK, ++mArpToken, 0),
mArpCheckIntervalMs);
}
mCurrentSignalLevel = calculateSignalLevel(msg.arg1);
//Ready to avoid bssid again ?
long time = android.os.SystemClock.elapsedRealtime();
if (time - mLastBssidAvoidedTime > MIN_INTERVAL_AVOID_BSSID_MS) {
handleRssiChange();
} else {
if (DBG) log("Early to avoid " + mWifiInfo + " time: " + time +
" last avoided: " + mLastBssidAvoidedTime);
}
break;
default:
@@ -725,10 +758,65 @@ public class WifiWatchdogStateMachine extends StateMachine {
}
}
class RssiMonitoringState extends State {
public void enter() {
if (DBG) log(getName() + "\n");
sendMessage(obtainMessage(CMD_RSSI_FETCH, ++mRssiFetchToken, 0));
}
public boolean processMessage(Message msg) {
switch (msg.what) {
case EVENT_RSSI_CHANGE:
mCurrentSignalLevel = calculateSignalLevel(msg.arg1);
if (mCurrentSignalLevel <= RSSI_LEVEL_CUTOFF) {
sendPoorLinkDetected();
} else if (mCurrentSignalLevel <= RSSI_LEVEL_MONITOR) {
//stay here;
} else {
//We dont need frequent RSSI monitoring any more
transitionTo(mOnlineWatchState);
}
break;
case CMD_RSSI_FETCH:
if (msg.arg1 == mRssiFetchToken) {
mWsmChannel.sendMessage(RSSI_FETCH);
sendMessageDelayed(obtainMessage(CMD_RSSI_FETCH, ++mRssiFetchToken, 0),
mRssiFetchIntervalMs);
}
break;
case RSSI_FETCH_SUCCEEDED:
int rssi = msg.arg1;
if (DBG) log("RSSI_FETCH_SUCCEEDED: " + rssi);
if (msg.arg1 < RSSI_MONITOR_THRESHOLD) {
mRssiMonitorCount++;
} else {
mRssiMonitorCount = 0;
}
if (mRssiMonitorCount > RSSI_MONITOR_COUNT) {
sendPoorLinkDetected();
++mRssiFetchToken;
}
break;
case RSSI_FETCH_FAILED:
//can happen if we are waiting to get a disconnect notification
if (DBG) log("RSSI_FETCH_FAILED");
break;
default:
return NOT_HANDLED;
}
return HANDLED;
}
}
/* Child state of ConnectedState indicating that we are online
* and there is nothing to do
*/
class OnlineState extends State {
@Override
public void enter() {
if (DBG) log(getName() + "\n");
}
}
private boolean shouldCheckWalledGarden() {
@@ -794,6 +882,20 @@ public class WifiWatchdogStateMachine extends StateMachine {
return success;
}
private int calculateSignalLevel(int rssi) {
int signalLevel = WifiManager.calculateSignalLevel(rssi,
WifiManager.RSSI_LEVELS);
if (DBG) log("RSSI current: " + mCurrentSignalLevel + "new: " + rssi + ", " + signalLevel);
return signalLevel;
}
private void sendPoorLinkDetected() {
if (DBG) log("send POOR_LINK_DETECTED " + mWifiInfo);
mWsmChannel.sendMessage(POOR_LINK_DETECTED);
mLastAvoidedBssid = mWifiInfo.getBSSID();
mLastBssidAvoidedTime = android.os.SystemClock.elapsedRealtime();
}
/**
* Convenience function for retrieving a single secure settings value
* as a string with a default value.
@@ -844,11 +946,11 @@ public class WifiWatchdogStateMachine extends StateMachine {
return Settings.Secure.putInt(cr, name, value ? 1 : 0);
}
private void log(String s) {
private static void log(String s) {
Log.d(TAG, s);
}
private void loge(String s) {
private static void loge(String s) {
Log.e(TAG, s);
}
}