public final class DnsResolver {
method @NonNull public static android.net.DnsResolver getInstance();
- method public <T> void query(@Nullable android.net.Network, @NonNull byte[], int, @NonNull java.util.concurrent.Executor, @Nullable android.os.CancellationSignal, @NonNull android.net.DnsResolver.AnswerCallback<T>);
- method public <T> void query(@Nullable android.net.Network, @NonNull String, int, int, int, @NonNull java.util.concurrent.Executor, @Nullable android.os.CancellationSignal, @NonNull android.net.DnsResolver.AnswerCallback<T>);
- method public void query(@Nullable android.net.Network, @NonNull String, int, @NonNull java.util.concurrent.Executor, @Nullable android.os.CancellationSignal, @NonNull android.net.DnsResolver.InetAddressAnswerCallback);
+ method public void query(@Nullable android.net.Network, @NonNull String, int, @NonNull java.util.concurrent.Executor, @Nullable android.os.CancellationSignal, @NonNull android.net.DnsResolver.Callback<? super java.util.List<java.net.InetAddress>>);
+ method public void query(@Nullable android.net.Network, @NonNull String, int, int, @NonNull java.util.concurrent.Executor, @Nullable android.os.CancellationSignal, @NonNull android.net.DnsResolver.Callback<? super java.util.List<java.net.InetAddress>>);
+ method public void rawQuery(@Nullable android.net.Network, @NonNull byte[], int, @NonNull java.util.concurrent.Executor, @Nullable android.os.CancellationSignal, @NonNull android.net.DnsResolver.Callback<? super byte[]>);
+ method public void rawQuery(@Nullable android.net.Network, @NonNull String, int, int, int, @NonNull java.util.concurrent.Executor, @Nullable android.os.CancellationSignal, @NonNull android.net.DnsResolver.Callback<? super byte[]>);
field public static final int CLASS_IN = 1; // 0x1
+ field public static final int ERROR_PARSE = 0; // 0x0
+ field public static final int ERROR_SYSTEM = 1; // 0x1
field public static final int FLAG_EMPTY = 0; // 0x0
field public static final int FLAG_NO_CACHE_LOOKUP = 4; // 0x4
field public static final int FLAG_NO_CACHE_STORE = 2; // 0x2
field public static final int TYPE_AAAA = 28; // 0x1c
}
- public abstract static class DnsResolver.AnswerCallback<T> {
- ctor public DnsResolver.AnswerCallback(@NonNull android.net.DnsResolver.AnswerParser<T>);
- method public abstract void onAnswer(@NonNull T);
- method public abstract void onParseException(@NonNull android.net.ParseException);
- method public abstract void onQueryException(@NonNull android.system.ErrnoException);
+ public static interface DnsResolver.Callback<T> {
+ method public void onAnswer(@NonNull T, int);
+ method public void onError(@NonNull android.net.DnsResolver.DnsException);
}
- public static interface DnsResolver.AnswerParser<T> {
- method @NonNull public T parse(@NonNull byte[]) throws android.net.ParseException;
- }
-
- public abstract static class DnsResolver.InetAddressAnswerCallback extends android.net.DnsResolver.AnswerCallback<java.util.List<java.net.InetAddress>> {
- ctor public DnsResolver.InetAddressAnswerCallback();
- }
-
- public abstract static class DnsResolver.RawAnswerCallback extends android.net.DnsResolver.AnswerCallback<byte[]> {
- ctor public DnsResolver.RawAnswerCallback();
+ public static class DnsResolver.DnsException extends java.lang.Exception {
+ field public final int code;
}
public class InetAddresses {
}
public class ParseException extends java.lang.RuntimeException {
- ctor public ParseException(@NonNull String);
- ctor public ParseException(@NonNull String, @NonNull Throwable);
field public String response;
}
public static final int FLAG_NO_CACHE_STORE = 1 << 1;
public static final int FLAG_NO_CACHE_LOOKUP = 1 << 2;
+ @IntDef(prefix = { "ERROR_" }, value = {
+ ERROR_PARSE,
+ ERROR_SYSTEM
+ })
+ @Retention(RetentionPolicy.SOURCE)
+ @interface DnsError {}
+ /**
+ * Indicates that there was an error parsing the response the query.
+ * The cause of this error is available via getCause() and is a ParseException.
+ */
+ public static final int ERROR_PARSE = 0;
+ /**
+ * Indicates that there was an error sending the query.
+ * The cause of this error is available via getCause() and is an ErrnoException.
+ */
+ public static final int ERROR_SYSTEM = 1;
+
private static final int NETID_UNSET = 0;
private static final DnsResolver sInstance = new DnsResolver();
private DnsResolver() {}
/**
- * Answer parser for parsing raw answers
+ * Base interface for answer callbacks
*
- * @param <T> The type of the parsed answer
+ * @param <T> The type of the answer
*/
- public interface AnswerParser<T> {
- /**
- * Creates a <T> answer by parsing the given raw answer.
- *
- * @param rawAnswer the raw answer to be parsed
- * @return a parsed <T> answer
- * @throws ParseException if parsing failed
- */
- @NonNull T parse(@NonNull byte[] rawAnswer) throws ParseException;
- }
-
- /**
- * Base class for answer callbacks
- *
- * @param <T> The type of the parsed answer
- */
- public abstract static class AnswerCallback<T> {
- /** @hide */
- public final AnswerParser<T> parser;
-
- public AnswerCallback(@NonNull AnswerParser<T> parser) {
- this.parser = parser;
- };
-
+ public interface Callback<T> {
/**
* Success response to
- * {@link android.net.DnsResolver#query query()}.
+ * {@link android.net.DnsResolver#query query()} or
+ * {@link android.net.DnsResolver#rawQuery rawQuery()}.
*
* Invoked when the answer to a query was successfully parsed.
*
- * @param answer parsed answer to the query.
+ * @param answer <T> answer to the query.
+ * @param rcode The response code in the DNS response.
*
* {@see android.net.DnsResolver#query query()}
*/
- public abstract void onAnswer(@NonNull T answer);
-
+ void onAnswer(@NonNull T answer, int rcode);
/**
* Error response to
- * {@link android.net.DnsResolver#query query()}.
+ * {@link android.net.DnsResolver#query query()} or
+ * {@link android.net.DnsResolver#rawQuery rawQuery()}.
*
* Invoked when there is no valid answer to
* {@link android.net.DnsResolver#query query()}
+ * {@link android.net.DnsResolver#rawQuery rawQuery()}.
*
- * @param exception a {@link ParseException} object with additional
+ * @param error a {@link DnsException} object with additional
* detail regarding the failure
*/
- public abstract void onParseException(@NonNull ParseException exception);
-
- /**
- * Error response to
- * {@link android.net.DnsResolver#query query()}.
- *
- * Invoked if an error happens when
- * issuing the DNS query or receiving the result.
- * {@link android.net.DnsResolver#query query()}
- *
- * @param exception an {@link ErrnoException} object with additional detail
- * regarding the failure
- */
- public abstract void onQueryException(@NonNull ErrnoException exception);
+ void onError(@NonNull DnsException error);
}
/**
- * Callback for receiving raw answers
+ * Class to represent DNS error
*/
- public abstract static class RawAnswerCallback extends AnswerCallback<byte[]> {
- public RawAnswerCallback() {
- super(rawAnswer -> rawAnswer);
- }
- }
-
- /**
- * Callback for receiving parsed {@link InetAddress} answers
- *
- * Note that if the answer does not contain any IP addresses,
- * onAnswer will be called with an empty list.
- */
- public abstract static class InetAddressAnswerCallback
- extends AnswerCallback<List<InetAddress>> {
- public InetAddressAnswerCallback() {
- super(rawAnswer -> new DnsAddressAnswer(rawAnswer).getAddresses());
+ public static class DnsException extends Exception {
+ /**
+ * DNS error code as one of the ERROR_* constants
+ */
+ @DnsError public final int code;
+
+ DnsException(@DnsError int code, @Nullable Throwable cause) {
+ super(cause);
+ this.code = code;
}
}
/**
* Send a raw DNS query.
- * The answer will be provided asynchronously through the provided {@link AnswerCallback}.
+ * The answer will be provided asynchronously through the provided {@link Callback}.
*
* @param network {@link Network} specifying which network to query on.
* {@code null} for query on default network.
* @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 AnswerCallback} which will be called to notify the caller
+ * @param callback a {@link Callback} which will be called to notify the caller
* of the result of dns query.
*/
- public <T> void query(@Nullable Network network, @NonNull byte[] query, @QueryFlag int flags,
+ public void rawQuery(@Nullable Network network, @NonNull byte[] query, @QueryFlag int flags,
@NonNull @CallbackExecutor Executor executor,
@Nullable CancellationSignal cancellationSignal,
- @NonNull AnswerCallback<T> callback) {
+ @NonNull Callback<? super byte[]> callback) {
if (cancellationSignal != null && cancellationSignal.isCanceled()) {
return;
}
queryfd = resNetworkSend((network != null
? network.netId : NETID_UNSET), query, query.length, flags);
} catch (ErrnoException e) {
- executor.execute(() -> {
- callback.onQueryException(e);
- });
+ executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e)));
return;
}
/**
* Send a DNS query with the specified name, class and query type.
- * The answer will be provided asynchronously through the provided {@link AnswerCallback}.
+ * The answer will be provided asynchronously through the provided {@link Callback}.
*
* @param network {@link Network} specifying which network to query on.
* {@code null} for query on default network.
* @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 AnswerCallback} which will be called to notify the caller
+ * @param callback a {@link Callback} which will be called to notify the caller
* of the result of dns query.
*/
- public <T> void query(@Nullable Network network, @NonNull String domain,
+ public void rawQuery(@Nullable Network network, @NonNull String domain,
@QueryClass int nsClass, @QueryType int nsType, @QueryFlag int flags,
@NonNull @CallbackExecutor Executor executor,
@Nullable CancellationSignal cancellationSignal,
- @NonNull AnswerCallback<T> callback) {
+ @NonNull Callback<? super byte[]> callback) {
if (cancellationSignal != null && cancellationSignal.isCanceled()) {
return;
}
queryfd = resNetworkQuery((network != null
? network.netId : NETID_UNSET), domain, nsClass, nsType, flags);
} catch (ErrnoException e) {
- executor.execute(() -> {
- callback.onQueryException(e);
- });
+ executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e)));
return;
}
synchronized (lock) {
}
}
- private class InetAddressAnswerAccumulator extends InetAddressAnswerCallback {
+ private class InetAddressAnswerAccumulator implements Callback<byte[]> {
private final List<InetAddress> mAllAnswers;
- private ParseException mParseException;
- private ErrnoException mErrnoException;
- private final InetAddressAnswerCallback mUserCallback;
+ private int mRcode;
+ private DnsException mDnsException;
+ private final Callback<? super List<InetAddress>> mUserCallback;
private final int mTargetAnswerCount;
private int mReceivedAnswerCount = 0;
- InetAddressAnswerAccumulator(int size, @NonNull InetAddressAnswerCallback callback) {
+ InetAddressAnswerAccumulator(int size,
+ @NonNull Callback<? super List<InetAddress>> callback) {
mTargetAnswerCount = size;
mAllAnswers = new ArrayList<>();
mUserCallback = callback;
}
- private boolean maybeReportException() {
- if (mErrnoException != null) {
- mUserCallback.onQueryException(mErrnoException);
+ private boolean maybeReportError() {
+ if (mRcode != 0) {
+ mUserCallback.onAnswer(mAllAnswers, mRcode);
return true;
}
- if (mParseException != null) {
- mUserCallback.onParseException(mParseException);
+ if (mDnsException != null) {
+ mUserCallback.onError(mDnsException);
return true;
}
return false;
private void maybeReportAnswer() {
if (++mReceivedAnswerCount != mTargetAnswerCount) return;
- if (mAllAnswers.isEmpty() && maybeReportException()) return;
+ if (mAllAnswers.isEmpty() && maybeReportError()) return;
// TODO: Do RFC6724 sort.
- mUserCallback.onAnswer(mAllAnswers);
- }
-
- @Override
- public void onAnswer(@NonNull List<InetAddress> answer) {
- mAllAnswers.addAll(answer);
- maybeReportAnswer();
+ mUserCallback.onAnswer(mAllAnswers, mRcode);
}
@Override
- public void onParseException(@NonNull ParseException e) {
- mParseException = e;
+ public void onAnswer(@NonNull byte[] answer, int rcode) {
+ // If at least one query succeeded, return an rcode of 0.
+ // Otherwise, arbitrarily return the first rcode received.
+ if (mReceivedAnswerCount == 0 || rcode == 0) {
+ mRcode = rcode;
+ }
+ try {
+ mAllAnswers.addAll(new DnsAddressAnswer(answer).getAddresses());
+ } catch (ParseException e) {
+ mDnsException = new DnsException(ERROR_PARSE, e);
+ }
maybeReportAnswer();
}
@Override
- public void onQueryException(@NonNull ErrnoException e) {
- mErrnoException = e;
+ public void onError(@NonNull DnsException error) {
+ mDnsException = error;
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}.
+ * Send a DNS query with the specified name on a network with both IPv4 and IPv6,
+ * get back a set of InetAddresses asynchronously.
+ *
+ * This method will examine the connection ability on given network, and query IPv4
+ * and IPv6 if connection is available.
+ *
+ * If at least one query succeeded with valid answer, rcode will be 0
+ *
+ * The answer will be provided asynchronously through the provided {@link Callback}.
*
* @param network {@link Network} specifying which network to query on.
* {@code null} for query on default network.
* @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
+ * @param callback a {@link Callback} 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) {
+ @NonNull Callback<? super List<InetAddress>> callback) {
if (cancellationSignal != null && cancellationSignal.isCanceled()) {
return;
}
v6fd = resNetworkQuery((network != null
? network.netId : NETID_UNSET), domain, CLASS_IN, TYPE_AAAA, flags);
} catch (ErrnoException e) {
- executor.execute(() -> {
- callback.onQueryException(e);
- });
+ executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e)));
return;
}
queryCount++;
// Avoiding gateways drop packets if queries are sent too close together
try {
Thread.sleep(SLEEP_TIME_MS);
- } catch (InterruptedException ex) { }
+ } catch (InterruptedException ex) {
+ Thread.currentThread().interrupt();
+ }
if (queryIpv4) {
try {
? 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);
- });
+ executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e)));
return;
}
queryCount++;
}
}
- private <T> void registerFDListener(@NonNull Executor executor,
- @NonNull FileDescriptor queryfd, @NonNull AnswerCallback<T> answerCallback,
+ /**
+ * Send a DNS query with the specified name and query type, get back a set of
+ * InetAddresses asynchronously.
+ *
+ * The answer will be provided asynchronously through the provided {@link Callback}.
+ *
+ * @param network {@link Network} specifying which network to query on.
+ * {@code null} for query on default network.
+ * @param domain domain name to query
+ * @param nsType dns resource record (RR) type as one of the TYPE_* constants
+ * @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 a {@link Callback} which will be called to notify the caller
+ * of the result of dns query.
+ */
+ public void query(@Nullable Network network, @NonNull String domain,
+ @QueryType int nsType, @QueryFlag int flags,
+ @NonNull @CallbackExecutor Executor executor,
+ @Nullable CancellationSignal cancellationSignal,
+ @NonNull Callback<? super List<InetAddress>> callback) {
+ if (cancellationSignal != null && cancellationSignal.isCanceled()) {
+ return;
+ }
+ final Object lock = new Object();
+ final FileDescriptor queryfd;
+ try {
+ queryfd = resNetworkQuery((network != null
+ ? network.netId : NETID_UNSET), domain, CLASS_IN, nsType, flags);
+ } catch (ErrnoException e) {
+ executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e)));
+ return;
+ }
+ final InetAddressAnswerAccumulator accumulator =
+ new InetAddressAnswerAccumulator(1, callback);
+ synchronized (lock) {
+ registerFDListener(executor, queryfd, accumulator, cancellationSignal, lock);
+ if (cancellationSignal == null) return;
+ addCancellationSignal(cancellationSignal, queryfd, lock);
+ }
+ }
+
+ /**
+ * Class to retrieve DNS response
+ *
+ * @hide
+ */
+ public static final class DnsResponse {
+ public final @NonNull byte[] answerbuf;
+ public final int rcode;
+ public DnsResponse(@NonNull byte[] answerbuf, int rcode) {
+ this.answerbuf = answerbuf;
+ this.rcode = rcode;
+ }
+ }
+
+ private void registerFDListener(@NonNull Executor executor,
+ @NonNull FileDescriptor queryfd, @NonNull Callback<? super byte[]> answerCallback,
@Nullable CancellationSignal cancellationSignal, @NonNull Object lock) {
Looper.getMainLooper().getQueue().addOnFileDescriptorEventListener(
queryfd,
FD_EVENTS,
(fd, events) -> {
executor.execute(() -> {
+ DnsResponse resp = null;
+ ErrnoException exception = null;
synchronized (lock) {
if (cancellationSignal != null && cancellationSignal.isCanceled()) {
return;
}
- byte[] answerbuf = null;
try {
- answerbuf = resNetworkResult(fd); // Closes fd, marks it invalid.
+ resp = resNetworkResult(fd); // Closes fd, marks it invalid.
} catch (ErrnoException e) {
Log.e(TAG, "resNetworkResult:" + e.toString());
- answerCallback.onQueryException(e);
- return;
- }
-
- try {
- answerCallback.onAnswer(
- answerCallback.parser.parse(answerbuf));
- } catch (ParseException e) {
- answerCallback.onParseException(e);
+ exception = e;
}
}
+ if (exception != null) {
+ answerCallback.onError(new DnsException(ERROR_SYSTEM, exception));
+ return;
+ }
+ answerCallback.onAnswer(resp.answerbuf, resp.rcode);
});
// Unregister this fd listener
return 0;
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