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/*
* Copyright (C) 2016 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.metrics;
import android.net.NetworkCapabilities;
import com.android.internal.util.BitUtils;
import java.util.Arrays;
/**
* A batch of DNS events recorded by NetdEventListenerService for a specific network.
* {@hide}
*/
final public class DnsEvent {
private static final int SIZE_LIMIT = 20000;
// Network id of the network associated with the event, or 0 if unspecified.
public final int netId;
// Transports of the network associated with the event, as defined in NetworkCapabilities.
// It is the caller responsability to ensure the value of transports does not change between
// calls to addResult.
public final long transports;
// The number of DNS queries recorded. Queries are stored in the structure-of-array style where
// the eventTypes, returnCodes, and latenciesMs arrays have the same length and the i-th event
// is spread across the three array at position i.
public int eventCount;
// The number of successful DNS queries recorded.
public int successCount;
// The types of DNS queries as defined in INetdEventListener.
public byte[] eventTypes;
// Current getaddrinfo codes go from 1 to EAI_MAX = 15. gethostbyname returns errno, but there
// are fewer than 255 errno values. So we store the result code in a byte as well.
public byte[] returnCodes;
// Latencies in milliseconds of queries, stored as ints.
public int[] latenciesMs;
public DnsEvent(int netId, long transports, int initialCapacity) {
this.netId = netId;
this.transports = transports;
eventTypes = new byte[initialCapacity];
returnCodes = new byte[initialCapacity];
latenciesMs = new int[initialCapacity];
}
boolean addResult(byte eventType, byte returnCode, int latencyMs) {
boolean isSuccess = (returnCode == 0);
if (eventCount >= SIZE_LIMIT) {
// TODO: implement better rate limiting that does not biases metrics.
return isSuccess;
}
if (eventCount == eventTypes.length) {
resize((int) (1.4 * eventCount));
}
eventTypes[eventCount] = eventType;
returnCodes[eventCount] = returnCode;
latenciesMs[eventCount] = latencyMs;
eventCount++;
if (isSuccess) {
successCount++;
}
return isSuccess;
}
public void resize(int newLength) {
eventTypes = Arrays.copyOf(eventTypes, newLength);
returnCodes = Arrays.copyOf(returnCodes, newLength);
latenciesMs = Arrays.copyOf(latenciesMs, newLength);
}
@Override
public String toString() {
StringBuilder builder =
new StringBuilder("DnsEvent(").append("netId=").append(netId).append(", ");
for (int t : BitUtils.unpackBits(transports)) {
builder.append(NetworkCapabilities.transportNameOf(t)).append(", ");
}
builder.append(String.format("%d events, ", eventCount));
builder.append(String.format("%d success)", successCount));
return builder.toString();
}
}
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