Send packets from correct local address

transport-raknet/src/main/java/org/cloudburstmc/netty/channel/raknet/RakChildChannel.java

@@ -36,13 +36,15 @@ public class RakChildChannel extends AbstractChannel implements RakChannel {
 
     private final RakChannelConfig config;
     private final InetSocketAddress remoteAddress;
+    private final InetSocketAddress localAddress;
     private final DefaultChannelPipeline rakPipeline;
     private volatile boolean open = true;
     private volatile boolean active;
 
-    RakChildChannel(InetSocketAddress remoteAddress, RakServerChannel parent, long guid, int version, int mtu, Consumer<RakChannel> childConsumer) {
+    RakChildChannel(InetSocketAddress remoteAddress, InetSocketAddress localAddress, RakServerChannel parent, long guid, int version, int mtu, Consumer<RakChannel> childConsumer) {
         super(parent);
         this.remoteAddress = remoteAddress;
+        this.localAddress = localAddress;
         this.config = new DefaultRakSessionConfig(this);
         this.config.setGuid(guid);
         this.config.setProtocolVersion(version);
@@ -80,7 +82,7 @@ public ChannelPipeline rakPipeline() {
 
     @Override
     public SocketAddress localAddress0() {
-        return this.parent().localAddress();
+        return this.localAddress;
     }
 
     @Override

transport-raknet/src/main/java/org/cloudburstmc/netty/channel/raknet/RakServerChannel.java

@@ -74,7 +74,8 @@ public RakServerChannel(DatagramChannel channel, Consumer<RakChannel> childConsu
      * @param address remote address of new connection.
      * @return RakChildChannel instance of new channel.
      */
-    public RakChildChannel createChildChannel(InetSocketAddress address, long clientGuid, int protocolVersion, int mtu) {
+    public RakChildChannel createChildChannel(InetSocketAddress address, InetSocketAddress localAddress,
+                                              long clientGuid, int protocolVersion, int mtu) {
         RakChildChannel existingChannel = this.childChannelMap.get(address);
         if (this.config().getSendCookie() && existingChannel != null) {
             // We know this player is coming from this IP address due to the cookie, so we can safely close the existing channel.
@@ -84,7 +85,7 @@ public RakChildChannel createChildChannel(InetSocketAddress address, long client
             return null;
         }
 
-        RakChildChannel channel = new RakChildChannel(address, this, clientGuid, protocolVersion, mtu, childConsumer);
+        RakChildChannel channel = new RakChildChannel(address, localAddress, this, clientGuid, protocolVersion, mtu, childConsumer);
         channel.closeFuture().addListener((GenericFutureListener<ChannelFuture>) this::onChildClosed);
         // Fire channel thought ServerBootstrap,
         // register to eventLoop, assign default options and attributes

transport-raknet/src/main/java/org/cloudburstmc/netty/handler/codec/raknet/server/RakChildDatagramHandler.java

@@ -44,7 +44,8 @@ public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise)
 
         this.canFlush = true;
         promise.trySuccess();
-        DatagramPacket datagram = isDatagram ? (DatagramPacket) msg : new DatagramPacket((ByteBuf) msg, this.channel.remoteAddress());
+        DatagramPacket datagram = isDatagram ? (DatagramPacket) msg :
+                new DatagramPacket((ByteBuf) msg, this.channel.remoteAddress(), this.channel.localAddress());
 
         RakChannelMetrics metrics = this.channel.config().getMetrics();
         if (metrics != null) {

transport-raknet/src/main/java/org/cloudburstmc/netty/handler/codec/raknet/server/RakServerOfflineHandler.java

@@ -149,7 +149,7 @@ private void onUnconnectedPing(ChannelHandlerContext ctx, DatagramPacket packet,
             out.writeBytes(advertisement, advertisement.readerIndex(), advertisement.readableBytes());
         }
 
-        ctx.writeAndFlush(new DatagramPacket(out, packet.sender()));
+        ctx.writeAndFlush(RakUtils.datagramReply(out, packet));
     }
 
     private void onOpenConnectionRequest1(ChannelHandlerContext ctx, DatagramPacket packet, ByteBuf magicBuf, long guid) {
@@ -166,7 +166,7 @@ private void onOpenConnectionRequest1(ChannelHandlerContext ctx, DatagramPacket
         int[] supportedProtocols = ((RakServerChannelConfig) ctx.channel().config()).getSupportedProtocols();
         if (supportedProtocols != null && Arrays.binarySearch(supportedProtocols, protocolVersion) < 0) {
             int latestVersion = supportedProtocols[supportedProtocols.length - 1];
-            this.sendIncompatibleVersion(ctx, packet.sender(), latestVersion, magicBuf, guid);
+            this.sendIncompatibleVersion(ctx, packet, latestVersion, magicBuf, guid);
             return;
         }
 
@@ -200,7 +200,7 @@ private void onOpenConnectionRequest1(ChannelHandlerContext ctx, DatagramPacket
         }
         replyBuffer.writeShort(RakUtils.clamp(mtu, ((RakServerChannelConfig) ctx.channel().config()).getMinMtu(),
                 ((RakServerChannelConfig) ctx.channel().config()).getMaxMtu()));
-        ctx.writeAndFlush(new DatagramPacket(replyBuffer, sender));
+        ctx.writeAndFlush(RakUtils.datagramReply(replyBuffer, packet));
     }
 
     private void onOpenConnectionRequest2(ChannelHandlerContext ctx, DatagramPacket packet, ByteBuf magicBuf, long guid) {
@@ -248,19 +248,19 @@ private void onOpenConnectionRequest2(ChannelHandlerContext ctx, DatagramPacket
                         sender, mtu, minMtu, maxMtu);
             }
             // The client should have already negotiated a valid MTU
-            this.sendAlreadyConnected(ctx, sender, magicBuf, guid);
+            this.sendAlreadyConnected(ctx, packet, magicBuf, guid);
             return;
         }
 
         RakServerChannel serverChannel = (RakServerChannel) ctx.channel();
-        RakChildChannel channel = serverChannel.createChildChannel(sender, clientGuid, connection.protocolVersion, mtu);
+        RakChildChannel channel = serverChannel.createChildChannel(sender, packet.recipient(), clientGuid, connection.protocolVersion, mtu);
         if (channel == null) {
             if (log.isTraceEnabled()) {
                 log.trace("[{}] Received ID_OPEN_CONNECTION_REQUEST_2, but a channel already exists for this socket address",
                         sender);
             }
             // Already connected
-            this.sendAlreadyConnected(ctx, sender, magicBuf, guid);
+            this.sendAlreadyConnected(ctx, packet, magicBuf, guid);
             return;
         }
 
@@ -271,24 +271,24 @@ private void onOpenConnectionRequest2(ChannelHandlerContext ctx, DatagramPacket
         RakUtils.writeAddress(replyBuffer, packet.sender());
         replyBuffer.writeShort(mtu);
         replyBuffer.writeBoolean(false); // Security
-        ctx.writeAndFlush(new DatagramPacket(replyBuffer, packet.sender()));
+        ctx.writeAndFlush(RakUtils.datagramReply(replyBuffer, packet));
     }
 
-    private void sendIncompatibleVersion(ChannelHandlerContext ctx, InetSocketAddress sender, int protocolVersion, ByteBuf magicBuf, long guid) {
+    private void sendIncompatibleVersion(ChannelHandlerContext ctx, DatagramPacket request, int protocolVersion, ByteBuf magicBuf, long guid) {
         ByteBuf buffer = ctx.alloc().ioBuffer(26, 26);
         buffer.writeByte(ID_INCOMPATIBLE_PROTOCOL_VERSION);
         buffer.writeByte(protocolVersion);
         buffer.writeBytes(magicBuf, magicBuf.readerIndex(), magicBuf.readableBytes());
         buffer.writeLong(guid);
-        ctx.writeAndFlush(new DatagramPacket(buffer, sender));
+        ctx.writeAndFlush(RakUtils.datagramReply(buffer, request));
     }
 
-    private void sendAlreadyConnected(ChannelHandlerContext ctx, InetSocketAddress sender, ByteBuf magicBuf, long guid) {
+    private void sendAlreadyConnected(ChannelHandlerContext ctx, DatagramPacket request, ByteBuf magicBuf, long guid) {
         ByteBuf buffer = ctx.alloc().ioBuffer(25, 25);
         buffer.writeByte(ID_ALREADY_CONNECTED);
         buffer.writeBytes(magicBuf, magicBuf.readerIndex(), magicBuf.readableBytes());
         buffer.writeLong(guid);
-        ctx.writeAndFlush(new DatagramPacket(buffer, sender));
+        ctx.writeAndFlush(RakUtils.datagramReply(buffer, request));
     }
 
     private static class PendingConnection {

transport-raknet/src/main/java/org/cloudburstmc/netty/util/RakUtils.java

@@ -20,6 +20,7 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.DefaultChannelPipeline;
+import io.netty.channel.socket.DatagramPacket;
 
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
@@ -186,4 +187,8 @@ public static int powerOfTwoCeiling(int value) {
         value++;
         return value;
     }
+
+    public static DatagramPacket datagramReply(ByteBuf buf, DatagramPacket request) {
+        return new DatagramPacket(buf, request.sender(), request.recipient());
+    }
 }