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/*
* 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.text.TextUtils;
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.Objects;
import java.util.Set;
import java.util.StringJoiner;
/**
* A class representing a configuration for multicast routing.
*
* Internal usage to Connectivity
* @hide
*/
// @SystemApi(client = MODULE_LIBRARIES)
public final 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;
/** @hide */
@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;
/** @hide */
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 getMinimumScope() {
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> getListeningAddresses() {
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(@NonNull 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;
}
@NonNull
public static final Creator<MulticastRoutingConfig> CREATOR = new Creator<>() {
@Override
public MulticastRoutingConfig createFromParcel(@NonNull Parcel in) {
return new MulticastRoutingConfig(in);
}
@Override
public MulticastRoutingConfig[] newArray(int size) {
return new MulticastRoutingConfig[size];
}
};
private static String forwardingModeToString(final int forwardingMode) {
switch (forwardingMode) {
case FORWARD_NONE: return "NONE";
case FORWARD_SELECTED: return "SELECTED";
case FORWARD_WITH_MIN_SCOPE: return "WITH_MIN_SCOPE";
default: return "UNKNOWN";
}
}
public static final class Builder {
@MulticastForwardingMode
private final int mForwardingMode;
private int mMinScope;
private final ArraySet<Inet6Address> mListeningAddresses;
// The two constructors with runtime checks for the mode and scope are arguably
// less convenient than three static factory methods, but API guidelines mandates
// that Builders are built with a constructor and not factory methods.
/**
* Create a new builder for forwarding mode FORWARD_NONE or FORWARD_SELECTED.
*
* <p>On a Builder for FORWARD_NONE, no properties can be set.
* <p>On a Builder for FORWARD_SELECTED, listening addresses can be added and removed
* but the minimum scope can't be set.
*
* @param mode {@link #FORWARD_NONE} or {@link #FORWARD_SELECTED}. Any other
* value will result in IllegalArgumentException.
* @see #Builder(int, int)
*/
public Builder(@MulticastForwardingMode final int mode) {
if (FORWARD_NONE != mode && FORWARD_SELECTED != mode) {
if (FORWARD_WITH_MIN_SCOPE == mode) {
throw new IllegalArgumentException("FORWARD_WITH_MIN_SCOPE requires "
+ "passing the scope as a second argument");
} else {
throw new IllegalArgumentException("Unknown forwarding mode : " + mode);
}
}
mForwardingMode = mode;
mMinScope = MULTICAST_SCOPE_NONE;
mListeningAddresses = new ArraySet<>();
}
/**
* Create a new builder for forwarding mode FORWARD_WITH_MIN_SCOPE.
*
* <p>On this Builder the scope can be set with {@link #setMinimumScope}, but
* listening addresses can't be added or removed.
*
* @param mode Must be {@link #FORWARD_WITH_MIN_SCOPE}.
* @param scope the minimum scope for this multicast routing config.
* @see Builder#Builder(int)
*/
public Builder(@MulticastForwardingMode final int mode, int scope) {
if (FORWARD_WITH_MIN_SCOPE != mode) {
throw new IllegalArgumentException("Forwarding with a min scope must "
+ "use forward mode FORWARD_WITH_MIN_SCOPE");
}
mForwardingMode = mode;
mMinScope = scope;
mListeningAddresses = new ArraySet<>();
}
/**
* 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
*/
@NonNull
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
*/
@NonNull
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
*/
@NonNull
public Builder clearListeningAddress(@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.
*/
@NonNull
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;
}
}
public boolean equals(Object other) {
if (other == this) {
return true;
} else if (!(other instanceof MulticastRoutingConfig)) {
return false;
} else {
final MulticastRoutingConfig otherConfig = (MulticastRoutingConfig) other;
return mForwardingMode == otherConfig.mForwardingMode
&& mMinScope == otherConfig.mMinScope
&& mListeningAddresses.equals(otherConfig.mListeningAddresses);
}
}
public int hashCode() {
return Objects.hash(mForwardingMode, mMinScope, mListeningAddresses);
}
public String toString() {
final StringJoiner resultJoiner = new StringJoiner(" ", "{", "}");
resultJoiner.add("ForwardingMode:");
resultJoiner.add(modeToString(mForwardingMode));
if (mForwardingMode == FORWARD_WITH_MIN_SCOPE) {
resultJoiner.add("MinScope:");
resultJoiner.add(Integer.toString(mMinScope));
}
if (mForwardingMode == FORWARD_SELECTED && !mListeningAddresses.isEmpty()) {
resultJoiner.add("ListeningAddresses: [");
resultJoiner.add(TextUtils.join(",", mListeningAddresses));
resultJoiner.add("]");
}
return resultJoiner.toString();
}
}