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Unremove DnsResolver#query method used by external developers

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This method was removed as part of addressing API council feedback in b/129261432
Add back previous DnsResolver#query which is already being used by developers.

Bug: 129395490
Test: atest DnsResolverTest

Change-Id: Ic956db204f3940d39d42e1b11dda39e57d356fad
This commit is contained in:
Luke Huang
2019-03-28 13:56:31 +08:00
parent efa4301a7f
commit fb5afabcb8
1 changed files with 194 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

203
core/java/android/net/DnsResolver.java
View File

@@ -22,6 +22,10 @@ import static android.net.NetworkUtils.resNetworkResult;
import static android.net.NetworkUtils.resNetworkSend;
import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_ERROR;
import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_INPUT;
import static android.system.OsConstants.AF_INET;
import static android.system.OsConstants.AF_INET6;
import static android.system.OsConstants.IPPROTO_UDP;
import static android.system.OsConstants.SOCK_DGRAM;
import android.annotation.CallbackExecutor;
import android.annotation.IntDef;
@@ -30,12 +34,18 @@ import android.annotation.Nullable;
import android.os.CancellationSignal;
import android.os.Looper;
import android.system.ErrnoException;
import android.system.Os;
import android.util.Log;
import libcore.io.IoUtils;
import java.io.FileDescriptor;
import java.io.IOException;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
@@ -52,6 +62,7 @@ public final class DnsResolver {
private static final String TAG = "DnsResolver";
private static final int FD_EVENTS = EVENT_INPUT | EVENT_ERROR;
private static final int MAXPACKET = 8 * 1024;
private static final int SLEEP_TIME = 2;
@IntDef(prefix = { "CLASS_" }, value = {
CLASS_IN
@@ -188,9 +199,9 @@ public final class DnsResolver {
* Send a raw DNS query.
* The answer will be provided asynchronously through the provided {@link AnswerCallback}.
*
* @param network {@link Network} specifying which network for querying.
* @param network {@link Network} specifying which network to query on.
* {@code null} for query on default network.
* @param query blob message
* @param query blob message to query
* @param flags flags as a combination of the FLAGS_* constants
* @param executor The {@link Executor} that the callback should be executed on.
* @param cancellationSignal used by the caller to signal if the query should be
@@ -211,21 +222,23 @@ public final class DnsResolver {
queryfd = resNetworkSend((network != null
? network.netId : NETID_UNSET), query, query.length, flags);
} catch (ErrnoException e) {
executor.execute(() -> {
callback.onQueryException(e);
});
return;
}
maybeAddCancellationSignal(cancellationSignal, queryfd, lock);
registerFDListener(executor, queryfd, callback, cancellationSignal, lock);
maybeAddCancellationSignal(cancellationSignal, queryfd, lock);
}
/**
* Send a DNS query with the specified name, class and query type.
* The answer will be provided asynchronously through the provided {@link AnswerCallback}.
*
* @param network {@link Network} specifying which network for querying.
* @param network {@link Network} specifying which network to query on.
* {@code null} for query on default network.
* @param domain domain name for querying
* @param domain domain name to query
* @param nsClass dns class as one of the CLASS_* constants
* @param nsType dns resource record (RR) type as one of the TYPE_* constants
* @param flags flags as a combination of the FLAGS_* constants
@@ -249,12 +262,145 @@ public final class DnsResolver {
queryfd = resNetworkQuery((network != null
? network.netId : NETID_UNSET), domain, nsClass, nsType, flags);
} catch (ErrnoException e) {
executor.execute(() -> {
callback.onQueryException(e);
});
return;
}
maybeAddCancellationSignal(cancellationSignal, queryfd, lock);
registerFDListener(executor, queryfd, callback, cancellationSignal, lock);
maybeAddCancellationSignal(cancellationSignal, queryfd, lock);
}
private class InetAddressAnswerAccumulator extends InetAddressAnswerCallback {
private final List<InetAddress> mAllAnswers;
private ParseException mParseException;
private ErrnoException mErrnoException;
private final InetAddressAnswerCallback mUserCallback;
private final int mTargetAnswerCount;
private int mReceivedAnswerCount = 0;
InetAddressAnswerAccumulator(int size, @NonNull InetAddressAnswerCallback callback) {
mTargetAnswerCount = size;
mAllAnswers = new ArrayList<>();
mUserCallback = callback;
}
private boolean maybeReportException() {
if (mErrnoException != null) {
mUserCallback.onQueryException(mErrnoException);
return true;
}
if (mParseException != null) {
mUserCallback.onParseException(mParseException);
return true;
}
return false;
}
private void maybeReportAnswer() {
if (++mReceivedAnswerCount != mTargetAnswerCount) return;
if (mAllAnswers.isEmpty() && maybeReportException()) return;
// TODO: Do RFC6724 sort.
mUserCallback.onAnswer(mAllAnswers);
}
@Override
public void onAnswer(@NonNull List<InetAddress> answer) {
mAllAnswers.addAll(answer);
maybeReportAnswer();
}
@Override
public void onParseException(@NonNull ParseException e) {
mParseException = e;
maybeReportAnswer();
}
@Override
public void onQueryException(@NonNull ErrnoException e) {
mErrnoException = e;
maybeReportAnswer();
}
}
/**
* Send a DNS query with the specified name, get back a set of InetAddresses asynchronously.
* The answer will be provided asynchronously through the provided
* {@link InetAddressAnswerCallback}.
*
* @param network {@link Network} specifying which network to query on.
* {@code null} for query on default network.
* @param domain domain name to query
* @param flags flags as a combination of the FLAGS_* constants
* @param executor The {@link Executor} that the callback should be executed on.
* @param cancellationSignal used by the caller to signal if the query should be
* cancelled. May be {@code null}.
* @param callback an {@link InetAddressAnswerCallback} which will be called to notify the
* caller of the result of dns query.
*/
public void query(@Nullable Network network, @NonNull String domain, @QueryFlag int flags,
@NonNull @CallbackExecutor Executor executor,
@Nullable CancellationSignal cancellationSignal,
@NonNull InetAddressAnswerCallback callback) {
if (cancellationSignal != null && cancellationSignal.isCanceled()) {
return;
}
final Object lock = new Object();
final boolean queryIpv6 = haveIpv6(network);
final boolean queryIpv4 = haveIpv4(network);
final FileDescriptor v4fd;
final FileDescriptor v6fd;
int queryCount = 0;
if (queryIpv6) {
try {
v6fd = resNetworkQuery((network != null
? network.netId : NETID_UNSET), domain, CLASS_IN, TYPE_AAAA, flags);
} catch (ErrnoException e) {
executor.execute(() -> {
callback.onQueryException(e);
});
return;
}
queryCount++;
} else v6fd = null;
// TODO: Use device flag to controll the sleep time.
// Avoiding gateways drop packets if queries are sent too close together
try {
Thread.sleep(SLEEP_TIME);
} catch (InterruptedException ex) { }
if (queryIpv4) {
try {
v4fd = resNetworkQuery((network != null
? network.netId : NETID_UNSET), domain, CLASS_IN, TYPE_A, flags);
} catch (ErrnoException e) {
if (queryIpv6) resNetworkCancel(v6fd); // Closes fd, marks it invalid.
executor.execute(() -> {
callback.onQueryException(e);
});
return;
}
queryCount++;
} else v4fd = null;
final InetAddressAnswerAccumulator accumulator =
new InetAddressAnswerAccumulator(queryCount, callback);
if (queryIpv6) registerFDListener(executor, v6fd, accumulator, cancellationSignal, lock);
if (queryIpv4) registerFDListener(executor, v4fd, accumulator, cancellationSignal, lock);
if (cancellationSignal == null) return;
cancellationSignal.setOnCancelListener(() -> {
synchronized (lock) {
if (queryIpv4) cancelQuery(v4fd);
if (queryIpv6) cancelQuery(v6fd);
}
});
}
private <T> void registerFDListener(@NonNull Executor executor,
@@ -271,7 +417,7 @@ public final class DnsResolver {
}
byte[] answerbuf = null;
try {
answerbuf = resNetworkResult(fd);
answerbuf = resNetworkResult(fd); // Closes fd, marks it invalid.
} catch (ErrnoException e) {
Log.e(TAG, "resNetworkResult:" + e.toString());
answerCallback.onQueryException(e);
@@ -291,19 +437,54 @@ public final class DnsResolver {
});
}
private void cancelQuery(@NonNull FileDescriptor queryfd) {
if (!queryfd.valid()) return;
Looper.getMainLooper().getQueue().removeOnFileDescriptorEventListener(queryfd);
resNetworkCancel(queryfd); // Closes fd, marks it invalid.
}
private void maybeAddCancellationSignal(@Nullable CancellationSignal cancellationSignal,
@NonNull FileDescriptor queryfd, @NonNull Object lock) {
if (cancellationSignal == null) return;
cancellationSignal.setOnCancelListener(() -> {
synchronized (lock) {
if (!queryfd.valid()) return;
Looper.getMainLooper().getQueue()
.removeOnFileDescriptorEventListener(queryfd);
resNetworkCancel(queryfd);
cancelQuery(queryfd);
}
});
}
// These two functions match the behaviour of have_ipv4 and have_ipv6 in the native resolver.
private boolean haveIpv4(@Nullable Network network) {
final SocketAddress addrIpv4 =
new InetSocketAddress(InetAddresses.parseNumericAddress("8.8.8.8"), 0);
return checkConnectivity(network, AF_INET, addrIpv4);
}
private boolean haveIpv6(@Nullable Network network) {
final SocketAddress addrIpv6 =
new InetSocketAddress(InetAddresses.parseNumericAddress("2000::"), 0);
return checkConnectivity(network, AF_INET6, addrIpv6);
}
private boolean checkConnectivity(@Nullable Network network,
int domain, @NonNull SocketAddress addr) {
final FileDescriptor socket;
try {
socket = Os.socket(domain, SOCK_DGRAM, IPPROTO_UDP);
} catch (ErrnoException e) {
return false;
}
try {
if (network != null) network.bindSocket(socket);
Os.connect(socket, addr);
} catch (IOException | ErrnoException e) {
return false;
} finally {
IoUtils.closeQuietly(socket);
}
return true;
}
private static class DnsAddressAnswer extends DnsPacket {
private static final String TAG = "DnsResolver.DnsAddressAnswer";
private static final boolean DBG = false;