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Diffstat (limited to 'core/java/android/net/DnsResolver.java')
| -rw-r--r-- | core/java/android/net/DnsResolver.java | 577 |
1 files changed, 0 insertions, 577 deletions
diff --git a/core/java/android/net/DnsResolver.java b/core/java/android/net/DnsResolver.java deleted file mode 100644 index 3f7660f5709a..000000000000 --- a/core/java/android/net/DnsResolver.java +++ /dev/null @@ -1,577 +0,0 @@ -/* - * Copyright (C) 2019 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; - -import static android.net.NetworkUtils.getDnsNetwork; -import static android.net.NetworkUtils.resNetworkCancel; -import static android.net.NetworkUtils.resNetworkQuery; -import static android.net.NetworkUtils.resNetworkResult; -import static android.net.NetworkUtils.resNetworkSend; -import static android.net.util.DnsUtils.haveIpv4; -import static android.net.util.DnsUtils.haveIpv6; -import static android.net.util.DnsUtils.rfc6724Sort; -import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_ERROR; -import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_INPUT; -import static android.system.OsConstants.ENONET; - -import android.annotation.CallbackExecutor; -import android.annotation.IntDef; -import android.annotation.NonNull; -import android.annotation.Nullable; -import android.os.CancellationSignal; -import android.os.Looper; -import android.os.MessageQueue; -import android.system.ErrnoException; -import android.util.Log; - -import com.android.net.module.util.DnsPacket; - -import java.io.FileDescriptor; -import java.lang.annotation.Retention; -import java.lang.annotation.RetentionPolicy; -import java.net.InetAddress; -import java.net.UnknownHostException; -import java.util.ArrayList; -import java.util.List; -import java.util.concurrent.Executor; - -/** - * Dns resolver class for asynchronous dns querying - * - * Note that if a client sends a query with more than 1 record in the question section but - * the remote dns server does not support this, it may not respond at all, leading to a timeout. - * - */ -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_MS = 2; - - @IntDef(prefix = { "CLASS_" }, value = { - CLASS_IN - }) - @Retention(RetentionPolicy.SOURCE) - @interface QueryClass {} - public static final int CLASS_IN = 1; - - @IntDef(prefix = { "TYPE_" }, value = { - TYPE_A, - TYPE_AAAA - }) - @Retention(RetentionPolicy.SOURCE) - @interface QueryType {} - public static final int TYPE_A = 1; - public static final int TYPE_AAAA = 28; - - @IntDef(prefix = { "FLAG_" }, value = { - FLAG_EMPTY, - FLAG_NO_RETRY, - FLAG_NO_CACHE_STORE, - FLAG_NO_CACHE_LOOKUP - }) - @Retention(RetentionPolicy.SOURCE) - @interface QueryFlag {} - public static final int FLAG_EMPTY = 0; - public static final int FLAG_NO_RETRY = 1 << 0; - 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 {@link 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(); - - /** - * Get instance for DnsResolver - */ - public static @NonNull DnsResolver getInstance() { - return sInstance; - } - - private DnsResolver() {} - - /** - * Base interface for answer callbacks - * - * @param <T> The type of the answer - */ - public interface Callback<T> { - /** - * Success response to - * {@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 <T> answer to the query. - * @param rcode The response code in the DNS response. - * - * {@see android.net.DnsResolver#query query()} - */ - void onAnswer(@NonNull T answer, int rcode); - /** - * Error response to - * {@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 error a {@link DnsException} object with additional - * detail regarding the failure - */ - void onError(@NonNull DnsException error); - } - - /** - * Class to represent DNS error - */ - 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 Callback}. - * - * @param network {@link Network} specifying which network to query on. - * {@code null} for query on default network. - * @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 - * 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 rawQuery(@Nullable Network network, @NonNull byte[] query, @QueryFlag int flags, - @NonNull @CallbackExecutor Executor executor, - @Nullable CancellationSignal cancellationSignal, - @NonNull Callback<? super byte[]> callback) { - if (cancellationSignal != null && cancellationSignal.isCanceled()) { - return; - } - final Object lock = new Object(); - final FileDescriptor queryfd; - try { - queryfd = resNetworkSend((network != null) - ? network.getNetIdForResolv() : NETID_UNSET, query, query.length, flags); - } catch (ErrnoException e) { - executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e))); - return; - } - - synchronized (lock) { - registerFDListener(executor, queryfd, callback, cancellationSignal, lock); - if (cancellationSignal == null) return; - addCancellationSignal(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 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 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 - * @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 rawQuery(@Nullable Network network, @NonNull String domain, - @QueryClass int nsClass, @QueryType int nsType, @QueryFlag int flags, - @NonNull @CallbackExecutor Executor executor, - @Nullable CancellationSignal cancellationSignal, - @NonNull Callback<? super byte[]> callback) { - if (cancellationSignal != null && cancellationSignal.isCanceled()) { - return; - } - final Object lock = new Object(); - final FileDescriptor queryfd; - try { - queryfd = resNetworkQuery((network != null) - ? network.getNetIdForResolv() : NETID_UNSET, domain, nsClass, nsType, flags); - } catch (ErrnoException e) { - executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e))); - return; - } - synchronized (lock) { - registerFDListener(executor, queryfd, callback, cancellationSignal, lock); - if (cancellationSignal == null) return; - addCancellationSignal(cancellationSignal, queryfd, lock); - } - } - - private class InetAddressAnswerAccumulator implements Callback<byte[]> { - private final List<InetAddress> mAllAnswers; - private final Network mNetwork; - private int mRcode; - private DnsException mDnsException; - private final Callback<? super List<InetAddress>> mUserCallback; - private final int mTargetAnswerCount; - private int mReceivedAnswerCount = 0; - - InetAddressAnswerAccumulator(@NonNull Network network, int size, - @NonNull Callback<? super List<InetAddress>> callback) { - mNetwork = network; - mTargetAnswerCount = size; - mAllAnswers = new ArrayList<>(); - mUserCallback = callback; - } - - private boolean maybeReportError() { - if (mRcode != 0) { - mUserCallback.onAnswer(mAllAnswers, mRcode); - return true; - } - if (mDnsException != null) { - mUserCallback.onError(mDnsException); - return true; - } - return false; - } - - private void maybeReportAnswer() { - if (++mReceivedAnswerCount != mTargetAnswerCount) return; - if (mAllAnswers.isEmpty() && maybeReportError()) return; - mUserCallback.onAnswer(rfc6724Sort(mNetwork, mAllAnswers), mRcode); - } - - @Override - 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 (DnsPacket.ParseException e) { - // Convert the com.android.net.module.util.DnsPacket.ParseException to an - // android.net.ParseException. This is the type that was used in Q and is implied - // by the public documentation of ERROR_PARSE. - // - // DnsPacket cannot throw android.net.ParseException directly because it's @hide. - ParseException pe = new ParseException(e.reason, e.getCause()); - pe.setStackTrace(e.getStackTrace()); - mDnsException = new DnsException(ERROR_PARSE, pe); - } - maybeReportAnswer(); - } - - @Override - public void onError(@NonNull DnsException error) { - mDnsException = error; - maybeReportAnswer(); - } - } - - /** - * Send a DNS query with the specified name on a network with both IPv4 and IPv6, - * get back a set of InetAddresses with rfc6724 sorting style 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 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 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 Callback<? super List<InetAddress>> callback) { - if (cancellationSignal != null && cancellationSignal.isCanceled()) { - return; - } - final Object lock = new Object(); - final Network queryNetwork; - try { - queryNetwork = (network != null) ? network : getDnsNetwork(); - } catch (ErrnoException e) { - executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e))); - return; - } - final boolean queryIpv6 = haveIpv6(queryNetwork); - final boolean queryIpv4 = haveIpv4(queryNetwork); - - // This can only happen if queryIpv4 and queryIpv6 are both false. - // This almost certainly means that queryNetwork does not exist or no longer exists. - if (!queryIpv6 && !queryIpv4) { - executor.execute(() -> callback.onError( - new DnsException(ERROR_SYSTEM, new ErrnoException("resNetworkQuery", ENONET)))); - return; - } - - final FileDescriptor v4fd; - final FileDescriptor v6fd; - - int queryCount = 0; - - if (queryIpv6) { - try { - v6fd = resNetworkQuery(queryNetwork.getNetIdForResolv(), domain, CLASS_IN, - TYPE_AAAA, flags); - } catch (ErrnoException e) { - executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e))); - return; - } - queryCount++; - } else v6fd = null; - - // Avoiding gateways drop packets if queries are sent too close together - try { - Thread.sleep(SLEEP_TIME_MS); - } catch (InterruptedException ex) { - Thread.currentThread().interrupt(); - } - - if (queryIpv4) { - try { - v4fd = resNetworkQuery(queryNetwork.getNetIdForResolv(), domain, CLASS_IN, TYPE_A, - flags); - } catch (ErrnoException e) { - if (queryIpv6) resNetworkCancel(v6fd); // Closes fd, marks it invalid. - executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e))); - return; - } - queryCount++; - } else v4fd = null; - - final InetAddressAnswerAccumulator accumulator = - new InetAddressAnswerAccumulator(queryNetwork, queryCount, callback); - - synchronized (lock) { - 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); - } - }); - } - } - - /** - * Send a DNS query with the specified name and query type, get back a set of - * InetAddresses with rfc6724 sorting style 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; - final Network queryNetwork; - try { - queryNetwork = (network != null) ? network : getDnsNetwork(); - queryfd = resNetworkQuery(queryNetwork.getNetIdForResolv(), domain, CLASS_IN, nsType, - flags); - } catch (ErrnoException e) { - executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e))); - return; - } - final InetAddressAnswerAccumulator accumulator = - new InetAddressAnswerAccumulator(queryNetwork, 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) { - final MessageQueue mainThreadMessageQueue = Looper.getMainLooper().getQueue(); - mainThreadMessageQueue.addOnFileDescriptorEventListener( - queryfd, - FD_EVENTS, - (fd, events) -> { - // b/134310704 - // Unregister fd event listener before resNetworkResult is called to prevent - // race condition caused by fd reused. - // For example when querying v4 and v6, it's possible that the first query ends - // and the fd is closed before the second request starts, which might return - // the same fd for the second request. By that time, the looper must have - // unregistered the fd, otherwise another event listener can't be registered. - mainThreadMessageQueue.removeOnFileDescriptorEventListener(fd); - - executor.execute(() -> { - DnsResponse resp = null; - ErrnoException exception = null; - synchronized (lock) { - if (cancellationSignal != null && cancellationSignal.isCanceled()) { - return; - } - try { - resp = resNetworkResult(fd); // Closes fd, marks it invalid. - } catch (ErrnoException e) { - Log.e(TAG, "resNetworkResult:" + e.toString()); - exception = e; - } - } - if (exception != null) { - answerCallback.onError(new DnsException(ERROR_SYSTEM, exception)); - return; - } - answerCallback.onAnswer(resp.answerbuf, resp.rcode); - }); - - // The file descriptor has already been unregistered, so it does not really - // matter what is returned here. In spirit 0 (meaning "unregister this FD") - // is still the closest to what the looper needs to do. When returning 0, - // Looper knows to ignore the fd if it has already been unregistered. - return 0; - }); - } - - private void cancelQuery(@NonNull FileDescriptor queryfd) { - if (!queryfd.valid()) return; - Looper.getMainLooper().getQueue().removeOnFileDescriptorEventListener(queryfd); - resNetworkCancel(queryfd); // Closes fd, marks it invalid. - } - - private void addCancellationSignal(@NonNull CancellationSignal cancellationSignal, - @NonNull FileDescriptor queryfd, @NonNull Object lock) { - cancellationSignal.setOnCancelListener(() -> { - synchronized (lock) { - cancelQuery(queryfd); - } - }); - } - - private static class DnsAddressAnswer extends DnsPacket { - private static final String TAG = "DnsResolver.DnsAddressAnswer"; - private static final boolean DBG = false; - - private final int mQueryType; - - DnsAddressAnswer(@NonNull byte[] data) throws ParseException { - super(data); - if ((mHeader.flags & (1 << 15)) == 0) { - throw new ParseException("Not an answer packet"); - } - if (mHeader.getRecordCount(QDSECTION) == 0) { - throw new ParseException("No question found"); - } - // Expect only one question in question section. - mQueryType = mRecords[QDSECTION].get(0).nsType; - } - - public @NonNull List<InetAddress> getAddresses() { - final List<InetAddress> results = new ArrayList<InetAddress>(); - if (mHeader.getRecordCount(ANSECTION) == 0) return results; - - for (final DnsRecord ansSec : mRecords[ANSECTION]) { - // Only support A and AAAA, also ignore answers if query type != answer type. - int nsType = ansSec.nsType; - if (nsType != mQueryType || (nsType != TYPE_A && nsType != TYPE_AAAA)) { - continue; - } - try { - results.add(InetAddress.getByAddress(ansSec.getRR())); - } catch (UnknownHostException e) { - if (DBG) { - Log.w(TAG, "rr to address fail"); - } - } - } - return results; - } - } - -} |