Move module sources to packages/Connectivity

Files that are planned to be part of the connectivity module are grouped
in packages/Connectivity, so they can be built separately and moved in
one operation with their history into packages/modules/Connectivity.

This places the files in the existing framework-connectivity-sources
filegroup instead of the current framework-core-sources filegroup. Both
are used the same way in framework-non-updatable-sources.

Bug: 171540887
Test: m
Change-Id: I62d9d91574ace6f5c4624035d190260c3126b91e
diff --git a/framework/src/android/net/DnsResolver.java b/framework/src/android/net/DnsResolver.java
new file mode 100644
index 0000000..3f7660f
--- /dev/null
+++ b/framework/src/android/net/DnsResolver.java
@@ -0,0 +1,577 @@
+/*
+ * 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;
+        }
+    }
+
+}