Add LocalNetworkConfig

This doesn't do anything at this patchset, but the whole
pipe from the agent to ConnectivityService is built.

LocalNetworkInfo will be the name of the public information
sent in callbacks to clients.

Test: CSLocalAgentTests
Change-Id: I70e133031ef3b0aaf6c3e59ccc2ad895c66d339c
diff --git a/framework/src/android/net/MulticastRoutingConfig.java b/framework/src/android/net/MulticastRoutingConfig.java
new file mode 100644
index 0000000..ebd9fc5
--- /dev/null
+++ b/framework/src/android/net/MulticastRoutingConfig.java
@@ -0,0 +1,264 @@
+/*
+ * Copyright (C) 2023 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 android.annotation.IntDef;
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.util.ArraySet;
+import android.util.Log;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.net.Inet6Address;
+import java.net.UnknownHostException;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Set;
+
+/**
+ * A class representing a configuration for multicast routing.
+ *
+ * Internal usage to Connectivity
+ * @hide
+ */
+// TODO : @SystemApi
+public class MulticastRoutingConfig implements Parcelable {
+    private static final String TAG = MulticastRoutingConfig.class.getSimpleName();
+
+    /** Do not forward any multicast packets. */
+    public static final int FORWARD_NONE = 0;
+    /**
+     * Forward only multicast packets with destination in the list of listening addresses.
+     * Ignore the min scope.
+     */
+    public static final int FORWARD_SELECTED = 1;
+    /**
+     * Forward all multicast packets with scope greater or equal than the min scope.
+     * Ignore the list of listening addresses.
+     */
+    public static final int FORWARD_WITH_MIN_SCOPE = 2;
+
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(prefix = { "FORWARD_" }, value = {
+            FORWARD_NONE,
+            FORWARD_SELECTED,
+            FORWARD_WITH_MIN_SCOPE
+    })
+    public @interface MulticastForwardingMode {}
+
+    /**
+     * Not a multicast scope, for configurations that do not use the min scope.
+     */
+    public static final int MULTICAST_SCOPE_NONE = -1;
+
+    public static final MulticastRoutingConfig CONFIG_FORWARD_NONE =
+            new MulticastRoutingConfig(FORWARD_NONE, MULTICAST_SCOPE_NONE, null);
+
+    @MulticastForwardingMode
+    private final int mForwardingMode;
+
+    private final int mMinScope;
+
+    @NonNull
+    private final Set<Inet6Address> mListeningAddresses;
+
+    private MulticastRoutingConfig(@MulticastForwardingMode final int mode, final int scope,
+            @Nullable final Set<Inet6Address> addresses) {
+        mForwardingMode = mode;
+        mMinScope = scope;
+        if (null != addresses) {
+            mListeningAddresses = Collections.unmodifiableSet(new ArraySet<>(addresses));
+        } else {
+            mListeningAddresses = Collections.emptySet();
+        }
+    }
+
+    /**
+     * Returns the forwarding mode.
+     */
+    @MulticastForwardingMode
+    public int getForwardingMode() {
+        return mForwardingMode;
+    }
+
+    /**
+     * Returns the minimal group address scope that is allowed for forwarding.
+     * If the forwarding mode is not FORWARD_WITH_MIN_SCOPE, will be MULTICAST_SCOPE_NONE.
+     */
+    public int getMinScope() {
+        return mMinScope;
+    }
+
+    /**
+     * Returns the list of group addresses listened by the outgoing interface.
+     * The list will be empty if the forwarding mode is not FORWARD_SELECTED.
+     */
+    @NonNull
+    public Set<Inet6Address> getMulticastListeningAddresses() {
+        return mListeningAddresses;
+    }
+
+    private MulticastRoutingConfig(Parcel in) {
+        mForwardingMode = in.readInt();
+        mMinScope = in.readInt();
+        final int count = in.readInt();
+        final ArraySet<Inet6Address> listeningAddresses = new ArraySet<>(count);
+        final byte[] buffer = new byte[16]; // Size of an Inet6Address
+        for (int i = 0; i < count; ++i) {
+            in.readByteArray(buffer);
+            try {
+                listeningAddresses.add((Inet6Address) Inet6Address.getByAddress(buffer));
+            } catch (UnknownHostException e) {
+                Log.wtf(TAG, "Can't read inet6address : " + Arrays.toString(buffer));
+            }
+        }
+        mListeningAddresses = Collections.unmodifiableSet(listeningAddresses);
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeInt(mForwardingMode);
+        dest.writeInt(mMinScope);
+        dest.writeInt(mListeningAddresses.size());
+        for (final Inet6Address addr : mListeningAddresses) {
+            dest.writeByteArray(addr.getAddress());
+        }
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    public static final Creator<MulticastRoutingConfig> CREATOR = new Creator<>() {
+        @Override
+        public MulticastRoutingConfig createFromParcel(Parcel in) {
+            return new MulticastRoutingConfig(in);
+        }
+
+        @Override
+        public MulticastRoutingConfig[] newArray(int size) {
+            return new MulticastRoutingConfig[size];
+        }
+    };
+
+    public static class Builder {
+        @MulticastForwardingMode
+        private final int mForwardingMode;
+        private int mMinScope;
+        private final ArraySet<Inet6Address> mListeningAddresses;
+
+        private Builder(@MulticastForwardingMode final int mode, int scope) {
+            mForwardingMode = mode;
+            mMinScope = scope;
+            mListeningAddresses = new ArraySet<>();
+        }
+
+        /**
+         * Create a builder that forwards nothing.
+         * No properties can be set on such a builder.
+         */
+        public static Builder newBuilderForwardingNone() {
+            return new Builder(FORWARD_NONE, MULTICAST_SCOPE_NONE);
+        }
+
+        /**
+         * Create a builder that forwards packets above a certain scope
+         *
+         * The scope can be changed on this builder, but not the listening addresses.
+         * @param scope the initial scope
+         */
+        public static Builder newBuilderWithMinScope(final int scope) {
+            return new Builder(FORWARD_WITH_MIN_SCOPE, scope);
+        }
+
+        /**
+         * Create a builder that forwards a specified list of listening addresses.
+         *
+         * Addresses can be added and removed from this builder, but the scope can't be set.
+         */
+        public static Builder newBuilderWithListeningAddresses() {
+            return new Builder(FORWARD_SELECTED, MULTICAST_SCOPE_NONE);
+        }
+
+        /**
+         * Sets the minimum scope for this multicast routing config.
+         * This is only meaningful (indeed, allowed) for configs in FORWARD_WITH_MIN_SCOPE mode.
+         * @return this builder
+         */
+        public Builder setMinimumScope(final int scope) {
+            if (FORWARD_WITH_MIN_SCOPE != mForwardingMode) {
+                throw new IllegalArgumentException("Can't set the scope on a builder in mode "
+                        + modeToString(mForwardingMode));
+            }
+            mMinScope = scope;
+            return this;
+        }
+
+        /**
+         * Add an address to the set of listening addresses.
+         *
+         * This is only meaningful (indeed, allowed) for configs in FORWARD_SELECTED mode.
+         * If this address was already added, this is a no-op.
+         * @return this builder
+         */
+        public Builder addListeningAddress(@NonNull final Inet6Address address) {
+            if (FORWARD_SELECTED != mForwardingMode) {
+                throw new IllegalArgumentException("Can't add an address on a builder in mode "
+                        + modeToString(mForwardingMode));
+            }
+            // TODO : should we check that this is a multicast address ?
+            mListeningAddresses.add(address);
+            return this;
+        }
+
+        /**
+         * Remove an address from the set of listening addresses.
+         *
+         * This is only meaningful (indeed, allowed) for configs in FORWARD_SELECTED mode.
+         * If this address was not added, or was already removed, this is a no-op.
+         * @return this builder
+         */
+        public Builder removeListeningAddress(@NonNull final Inet6Address address) {
+            if (FORWARD_SELECTED != mForwardingMode) {
+                throw new IllegalArgumentException("Can't remove an address on a builder in mode "
+                        + modeToString(mForwardingMode));
+            }
+            mListeningAddresses.remove(address);
+            return this;
+        }
+
+        /**
+         * Build the config.
+         */
+        public MulticastRoutingConfig build() {
+            return new MulticastRoutingConfig(mForwardingMode, mMinScope, mListeningAddresses);
+        }
+    }
+
+    private static String modeToString(@MulticastForwardingMode final int mode) {
+        switch (mode) {
+            case FORWARD_NONE: return "FORWARD_NONE";
+            case FORWARD_SELECTED: return "FORWARD_SELECTED";
+            case FORWARD_WITH_MIN_SCOPE: return "FORWARD_WITH_MIN_SCOPE";
+            default: return "unknown multicast routing mode " + mode;
+        }
+    }
+}