Merge pull request #205 from SquidDev-CC/feature/packet-network-api

Expose wireless network in the public API

src/main/java/dan200/computercraft/ComputerCraft.java

@@ -11,6 +11,7 @@ import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
 import dan200.computercraft.api.media.IMedia;
 import dan200.computercraft.api.media.IMediaProvider;
+import dan200.computercraft.api.network.IPacketNetwork;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.IPeripheralProvider;
 import dan200.computercraft.api.permissions.ITurtlePermissionProvider;
@@ -736,6 +737,11 @@ public class ComputerCraft
         return upgrades;
     }
 
+    public IPacketNetwork getWirelessNetwork()
+    {
+        return WirelessNetwork.getUniversal();
+    }
+
     public static int createUniqueNumberedSaveDir( World world, String parentSubPath )
     {
         return IDAssigner.getNextIDFromDirectory(new File(getWorldDir(world), parentSubPath));

src/main/java/dan200/computercraft/api/ComputerCraftAPI.java

@@ -10,6 +10,7 @@ import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
 import dan200.computercraft.api.media.IMedia;
 import dan200.computercraft.api.media.IMediaProvider;
+import dan200.computercraft.api.network.IPacketNetwork;
 import dan200.computercraft.api.peripheral.IComputerAccess;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.IPeripheralProvider;
@@ -289,6 +290,27 @@ public final class ComputerCraftAPI
         }
     }
 
+    /**
+     * Attempt to get the game-wide wireless network.
+     *
+     * @return The global wireless network, or {@code null} if it could not be fetched.
+     */
+    public static IPacketNetwork getWirelessNetwork()
+    {
+        findCC();
+        if( computerCraft_getWirelessNetwork != null )
+        {
+            try
+            {
+                return (IPacketNetwork) computerCraft_getWirelessNetwork.invoke( null );
+            } catch (Exception e) {
+                // It failed;
+            }
+        }
+
+        return null;
+    }
+
     // The functions below here are private, and are used to interface with the non-API ComputerCraft classes.
     // Reflection is used here so you can develop your mod without decompiling ComputerCraft and including
     // it in your solution, and so your mod won't crash if ComputerCraft is installed.
@@ -330,6 +352,8 @@ public final class ComputerCraftAPI
                 computerCraft_registerPocketUpgrade = findCCMethod( "registerPocketUpgrade", new Class<?>[] {
                     IPocketUpgrade.class
                 } );
+                computerCraft_getWirelessNetwork = findCCMethod( "getWirelessNetwork", new Class<?>[] {
+                } );
             } catch( Exception e ) {
                 System.out.println( "ComputerCraftAPI: ComputerCraft not found." );
             } finally {
@@ -365,4 +389,5 @@ public final class ComputerCraftAPI
     private static Method computerCraft_registerMediaProvider = null;
     private static Method computerCraft_registerPermissionProvider = null;
     private static Method computerCraft_registerPocketUpgrade = null;
+    private static Method computerCraft_getWirelessNetwork = null;
 }

src/main/java/dan200/computercraft/api/network/IPacketNetwork.java

@@ -0,0 +1,58 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2017. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.api.network;
+
+import javax.annotation.Nonnull;
+
+/**
+ * A packet network represents a collection of devices which can send and receive packets.
+ *
+ * @see Packet
+ * @see IPacketReceiver
+ */
+public interface IPacketNetwork
+{
+    /**
+     * Add a receiver to the network.
+     *
+     * @param receiver The receiver to register to the network.
+     */
+    void addReceiver( @Nonnull IPacketReceiver receiver );
+
+    /**
+     * Remove a receiver from the network.
+     *
+     * @param receiver The device to remove from the network.
+     */
+    void removeReceiver( @Nonnull IPacketReceiver receiver );
+
+    /**
+     * Determine whether this network is wireless.
+     *
+     * @return Whether this network is wireless.
+     */
+    boolean isWireless();
+
+    /**
+     * Submit a packet for transmitting across the network. This will route the packet through the network, sending it
+     * to all receivers within range (or any interdimensional ones).
+     *
+     * @param packet The packet to send.
+     * @see #transmitInterdimensional(Packet) 
+     * @see IPacketReceiver#receiveSameDimension(Packet, double)
+     */
+    void transmitSameDimension( @Nonnull Packet packet, double range );
+
+    /**
+     * Submit a packet for transmitting across the network. This will route the packet through the network, sending it
+     * to all receivers across all dimensions.
+     *
+     * @param packet The packet to send.
+     * @see #transmitSameDimension(Packet, double) 
+     * @see IPacketReceiver#receiveDifferentDimension(Packet)
+     */
+    void transmitInterdimensional( @Nonnull Packet packet );
+}

src/main/java/dan200/computercraft/api/network/IPacketReceiver.java

@@ -0,0 +1,84 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2017. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.api.network;
+
+import net.minecraft.util.math.Vec3d;
+import net.minecraft.world.World;
+
+import javax.annotation.Nonnull;
+
+/**
+ * An object on an {@link IPacketNetwork}, capable of receiving packets.
+ */
+public interface IPacketReceiver
+{
+    /**
+     * Get the world in which this packet receiver exists.
+     *
+     * @return The receivers's world.
+     */
+    @Nonnull
+    World getWorld();
+
+    /**
+     * Get the position in the world at which this receiver exists.
+     *
+     * @return The receiver's position.
+     */
+    @Nonnull
+    Vec3d getPosition();
+
+    /**
+     * Get the maximum distance this receiver can send and receive messages.
+     *
+     * When determining whether a receiver can receive a message, the largest distance of the packet and receiver is
+     * used - ensuring it is within range. If the packet or receiver is inter-dimensional, then the packet will always
+     * be received.
+     *
+     * @return The maximum distance this device can send and receive messages.
+     * @see #isInterdimensional()
+     * @see #receiveSameDimension(Packet packet, double)
+     * @see IPacketNetwork#transmitInterdimensional(Packet)
+     */
+    double getRange();
+
+    /**
+     * Determine whether this receiver can receive packets from other dimensions.
+     *
+     * A device will receive an inter-dimensional packet if either it or the sending device is inter-dimensional.
+     *
+     * @return Whether this receiver receives packets from other dimensions.
+     * @see #getRange()
+     * @see #receiveDifferentDimension(Packet)
+     * @see IPacketNetwork#transmitInterdimensional(Packet) 
+     */
+    boolean isInterdimensional();
+
+    /**
+     * Receive a network packet from the same dimension.
+     *
+     * @param packet   The packet to receive. Generally you should check that you are listening on the given channel and,
+     *                 if so, queue the appropriate modem event.
+     * @param distance The distance this packet has travelled from the source.
+     * @see Packet
+     * @see #getRange()
+     * @see IPacketNetwork#transmitSameDimension(Packet, double)
+     * @see IPacketNetwork#transmitInterdimensional(Packet)
+     */
+    void receiveSameDimension( @Nonnull Packet packet, double distance );
+
+    /**
+     * Receive a network packet from a different dimension.
+     *
+     * @param packet The packet to receive. Generally you should check that you are listening on the given channel and,
+     *               if so, queue the appropriate modem event.
+     * @see Packet
+     * @see IPacketNetwork#transmitInterdimensional(Packet)
+     * @see IPacketNetwork#transmitSameDimension(Packet, double)
+     * @see #isInterdimensional()
+     */
+    void receiveDifferentDimension( @Nonnull Packet packet );
+}

src/main/java/dan200/computercraft/api/network/IPacketSender.java

@@ -0,0 +1,42 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2017. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.api.network;
+
+import net.minecraft.util.math.Vec3d;
+import net.minecraft.world.World;
+
+import javax.annotation.Nonnull;
+
+/**
+ * An object on a {@link IPacketNetwork}, capable of sending packets.
+ */
+public interface IPacketSender
+{
+    /**
+     * Get the world in which this packet sender exists.
+     *
+     * @return The sender's world.
+     */
+    @Nonnull
+    World getWorld();
+
+    /**
+     * Get the position in the world at which this sender exists.
+     *
+     * @return The sender's position.
+     */
+    @Nonnull
+    Vec3d getPosition();
+
+    /**
+     * Get some sort of identification string for this sender. This does not strictly need to be unique, but you
+     * should be able to extract some identifiable information from it.
+     *
+     * @return This device's id.
+     */
+    @Nonnull
+    String getSenderID();
+}

src/main/java/dan200/computercraft/api/network/Packet.java

@@ -0,0 +1,118 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2017. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.api.network;
+
+import com.google.common.base.Preconditions;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Represents a packet which may be sent across a {@link IPacketNetwork}.
+ *
+ * @see IPacketSender
+ * @see IPacketNetwork#transmitSameDimension(Packet, double)
+ * @see IPacketNetwork#transmitInterdimensional(Packet)
+ * @see IPacketReceiver#receiveDifferentDimension(Packet)
+ * @see IPacketReceiver#receiveSameDimension(Packet, double)
+ */
+public class Packet
+{
+    private final int m_channel;
+    private final int m_replyChannel;
+    private final Object m_payload;
+
+    private final IPacketSender m_sender;
+
+    /**
+     * Create a new packet, ready for transmitting across the network.
+     *
+     * @param channel      The channel to send the packet along. Receiving devices should only process packets from on
+     *                     channels they are listening to.
+     * @param replyChannel The channel to reply on.
+     * @param payload      The contents of this packet. This should be a "valid" Lua object, safe for queuing as an
+     *                     event or returning from a peripheral call.
+     * @param sender       The object which sent this packet.
+     */
+    public Packet( int channel, int replyChannel, @Nullable Object payload, @Nonnull IPacketSender sender )
+    {
+        Preconditions.checkNotNull( sender, "sender cannot be null" );
+
+        m_channel = channel;
+        m_replyChannel = replyChannel;
+        m_payload = payload;
+        m_sender = sender;
+    }
+
+    /**
+     * Get the channel this packet is sent along. Receivers should generally only process packets from on channels they
+     * are listening to.
+     *
+     * @return This packet's channel.
+     */
+    public int getChannel()
+    {
+        return m_channel;
+    }
+
+    /**
+     * The channel to reply on. Objects which will reply should send it along this channel.
+     *
+     * @return This channel to reply on.
+     */
+    public int getReplyChannel()
+    {
+        return m_replyChannel;
+    }
+
+    /**
+     * The actual data of this packet. This should be a "valid" Lua object, safe for queuing as an
+     * event or returning from a peripheral call.
+     *
+     * @return The packet's payload
+     */
+    @Nullable
+    public Object getPayload()
+    {
+        return m_payload;
+    }
+
+    /**
+     * The object which sent this message.
+     *
+     * @return The sending object.
+     */
+    @Nonnull
+    public IPacketSender getSender()
+    {
+        return m_sender;
+    }
+
+    @Override
+    public boolean equals( Object o )
+    {
+        if( this == o ) return true;
+        if( o == null || getClass() != o.getClass() ) return false;
+
+        Packet packet = (Packet) o;
+
+        if( m_channel != packet.m_channel ) return false;
+        if( m_replyChannel != packet.m_replyChannel ) return false;
+        if( m_payload != null ? !m_payload.equals( packet.m_payload ) : packet.m_payload != null ) return false;
+        return m_sender.equals( packet.m_sender );
+    }
+
+    @Override
+    public int hashCode()
+    {
+        int result;
+        result = m_channel;
+        result = 31 * result + m_replyChannel;
+        result = 31 * result + (m_payload != null ? m_payload.hashCode() : 0);
+        result = 31 * result + m_sender.hashCode();
+        return result;
+    }
+}

src/main/java/dan200/computercraft/api/network/package-info.java

@@ -0,0 +1,10 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2017. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+
+@API( owner="ComputerCraft", provides="ComputerCraft|API|Network", apiVersion="${version}" )
+package dan200.computercraft.api.network;
+
+import net.minecraftforge.fml.common.API;

src/main/java/dan200/computercraft/shared/peripheral/modem/INetwork.java

@@ -1,18 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2017. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-
-package dan200.computercraft.shared.peripheral.modem;
-
-import net.minecraft.util.math.Vec3d;
-import net.minecraft.world.World;
-
-public interface INetwork
-{
-    void addReceiver( IReceiver receiver );
-    void removeReceiver( IReceiver receiver );
-    void transmit( int channel, int replyChannel, Object payload, World world, Vec3d pos, double range, boolean interdimensional, Object senderObject );
-    boolean isWireless();
-}

src/main/java/dan200/computercraft/shared/peripheral/modem/IReceiver.java

@@ -1,20 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2017. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-
-package dan200.computercraft.shared.peripheral.modem;
-import net.minecraft.util.math.Vec3d;
-import net.minecraft.world.World;
-
-public interface IReceiver
-{
-    int getChannel();
-    World getWorld();
-    Vec3d getWorldPosition();
-    boolean isInterdimensional();
-    double getReceiveRange();
-    void receiveSameDimension( int replyChannel, Object payload, double distance, Object senderObject );
-    void receiveDifferentDimension( int replyChannel, Object payload, Object senderObject );
-}

src/main/java/dan200/computercraft/shared/peripheral/modem/ModemPeripheral.java

@@ -8,83 +8,25 @@ package dan200.computercraft.shared.peripheral.modem;
 
 import dan200.computercraft.api.lua.ILuaContext;
 import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.api.network.IPacketNetwork;
+import dan200.computercraft.api.network.IPacketReceiver;
+import dan200.computercraft.api.network.IPacketSender;
+import dan200.computercraft.api.network.Packet;
 import dan200.computercraft.api.peripheral.IComputerAccess;
 import dan200.computercraft.api.peripheral.IPeripheral;
+import gnu.trove.set.TIntSet;
+import gnu.trove.set.hash.TIntHashSet;
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
 import javax.annotation.Nonnull;
-import java.util.HashMap;
-import java.util.Map;
 
 public abstract class ModemPeripheral
-    implements IPeripheral
+    implements IPeripheral, IPacketSender, IPacketReceiver
 {
-    private static class SingleChannelReceiver implements IReceiver
-    {
-        private ModemPeripheral m_owner;
-        private int m_channel;
-        
-        public SingleChannelReceiver( ModemPeripheral owner, int channel )
-        {
-            m_owner = owner;
-            m_channel = channel;
-        }
-        
-        // IReceiver implementation
-        
-        @Override
-        public int getChannel()
-        {
-            return m_channel;
-        }
-
-        @Override
-        public World getWorld()
-        {
-            return m_owner.getWorld();
-        }
-
-        @Override
-        public Vec3d getWorldPosition()
-        {
-            return m_owner.getWorldPosition();
-        }
-        
-        @Override
-        public boolean isInterdimensional()
-        {
-            return m_owner.isInterdimensional();
-        }
-
-        @Override
-        public double getReceiveRange()
-        {
-            return m_owner.getReceiveRange();
-        }
-
-        @Override
-        public void receiveSameDimension( int replyChannel, Object payload, double distance, Object senderObject )
-        {
-            if( senderObject != m_owner )
-            {
-                m_owner.receiveSameDimension( m_channel, replyChannel, payload, distance );
-            }
-        }
-
-        @Override
-        public void receiveDifferentDimension( int replyChannel, Object payload, Object senderObject )
-        {
-            if( senderObject != m_owner )
-            {
-                m_owner.receiveDifferentDimension( m_channel, replyChannel, payload );
-            }
-        }
-    }
-    
-    private INetwork m_network;
+    private IPacketNetwork m_network;
     private IComputerAccess m_computer;
-    private final Map<Integer, IReceiver> m_channels;
+    private final TIntSet m_channels;
 
     private boolean m_open;
     private boolean m_changed;
@@ -93,23 +35,19 @@ public abstract class ModemPeripheral
     {
         m_network = null;
         m_computer = null;
-        
-        m_channels = new HashMap<Integer, IReceiver>();
+        m_channels = new TIntHashSet();
         m_open = false;
         m_changed = true;
     }
 
-    private synchronized void setNetwork( INetwork network )
+    private synchronized void setNetwork( IPacketNetwork network )
     {
         if( m_network != network )
         {
             // Leave old network
             if( m_network != null )
             {
-                for( IReceiver iReceiver : m_channels.values() )
-                {
-                    m_network.removeReceiver( iReceiver );
-                }
+                m_network.removeReceiver( this );
             }
 
             // Set new network
@@ -118,10 +56,7 @@ public abstract class ModemPeripheral
             // Join new network
             if( m_network != null )
             {
-                for( IReceiver iReceiver : m_channels.values() )
-                {
-                    m_network.addReceiver( iReceiver );
-                }
+                m_network.addReceiver( this );
             }
         }
     }
@@ -131,10 +66,6 @@ public abstract class ModemPeripheral
         setNetwork( getNetwork() );
     }
 
-    protected abstract World getWorld();
-
-    protected abstract Vec3d getPosition();
-        
     public synchronized void destroy()
     {
         setNetwork( null );
@@ -152,52 +83,44 @@ public abstract class ModemPeripheral
         return false;
     }
 
-    protected abstract double getTransmitRange();
-
-    protected abstract boolean isInterdimensional();
-
     public synchronized boolean isActive()
     {
         return (m_computer != null) && m_open;
     }
 
-    public synchronized Vec3d getWorldPosition()
+    @Override
+    public void receiveSameDimension( @Nonnull Packet packet, double distance )
     {
-        return getPosition();
-    }
+        if( packet.getSender() == this ) return;
 
-    public synchronized double getReceiveRange()
-    {
-        return getTransmitRange();
-    }
-    
-    public void receiveSameDimension( int channel, int replyChannel, Object payload, double distance )
-    {
         synchronized (m_channels)
         {
-            if( m_computer != null && m_channels.containsKey( channel ) )
+            if( m_computer != null && m_channels.contains( packet.getChannel() ) )
             {
                 m_computer.queueEvent( "modem_message", new Object[] {
-                    m_computer.getAttachmentName(), channel, replyChannel, payload, distance
+                    m_computer.getAttachmentName(), packet.getChannel(), packet.getReplyChannel(), packet.getPayload(), distance
                 } );
             }
         }
     }
 
-    public void receiveDifferentDimension( int channel, int replyChannel, Object payload )
+    @Override
+    public void receiveDifferentDimension( @Nonnull Packet packet )
     {
+        if( packet.getSender() == this ) return;
+
         synchronized (m_channels)
         {
-            if( m_computer != null && m_channels.containsKey( channel ) )
+            if( m_computer != null && m_channels.contains( packet.getChannel() ) )
             {
                 m_computer.queueEvent( "modem_message", new Object[] {
-                        m_computer.getAttachmentName(), channel, replyChannel, payload
+                    m_computer.getAttachmentName(), packet.getChannel(), packet.getReplyChannel(), packet.getPayload()
                 } );
             }
         }
     }
 
-    protected abstract INetwork getNetwork();
+    protected abstract IPacketNetwork getNetwork();
     
     // IPeripheral implementation
 
@@ -247,19 +170,14 @@ public abstract class ModemPeripheral
                 int channel = parseChannel( arguments, 0 );
                 synchronized( this )
                 {
-                    if( !m_channels.containsKey( channel ) )
+                    if( !m_channels.contains( channel ) )
                     {
                         if( m_channels.size() >= 128 )
                         {
                             throw new LuaException( "Too many open channels" );
                         }
 
-                        IReceiver receiver = new SingleChannelReceiver( this, channel );
-                        m_channels.put( channel, receiver );
-                        if( m_network != null )
-                        {
-                            m_network.addReceiver( receiver );
-                        }
+                        m_channels.add( channel );
                         if( !m_open )
                         {
                             m_open = true;
@@ -275,7 +193,7 @@ public abstract class ModemPeripheral
                 int channel = parseChannel( arguments, 0 );
                 synchronized( this )
                 {
-                    boolean open = m_channels.containsKey( channel );
+                    boolean open = m_channels.contains( channel );
                     return new Object[] { open };
                 }
             }
@@ -285,15 +203,8 @@ public abstract class ModemPeripheral
                 int channel = parseChannel( arguments, 0 );
                 synchronized( this )
                 {
-                    if( m_channels.containsKey( channel ) )
+                    if( m_channels.remove( channel ) )
                     {
-                        IReceiver receiver = m_channels.get( channel );
-                        if( m_network != null )
-                        {
-                            m_network.removeReceiver( receiver );
-                        }
-                        m_channels.remove( channel );
-                        
                         if( m_channels.size() == 0 )
                         {
                             m_open = false;
@@ -310,13 +221,6 @@ public abstract class ModemPeripheral
                 {
                     if( m_channels.size() > 0 )
                     {
-                        if( m_network != null )
-                        {
-                            for( IReceiver iReceiver : m_channels.values() )
-                            {
-                                m_network.removeReceiver( iReceiver );
-                            }
-                        }
                         m_channels.clear();
                         
                         if( m_open )
@@ -340,7 +244,15 @@ public abstract class ModemPeripheral
                     Vec3d position = getPosition();
                     if( world != null && position != null && m_network != null)
                     {
-                        m_network.transmit( channel, replyChannel, payload, world, position, getTransmitRange(), isInterdimensional(), this );
+                        Packet packet = new Packet( channel, replyChannel, payload, this );
+                        if( isInterdimensional() )
+                        {
+                            m_network.transmitInterdimensional( packet );
+                        }
+                        else
+                        {
+                            m_network.transmitSameDimension( packet, getRange() );
+                        }
                     }
                 }
                 return null;
@@ -377,10 +289,7 @@ public abstract class ModemPeripheral
     {
         if( m_network != null )
         {
-            for( IReceiver iReceiver : m_channels.values() )
-            {
-                m_network.removeReceiver( iReceiver );
-            }
+            m_network.removeReceiver( this );
             m_channels.clear();
             m_network = null;
         }
@@ -394,11 +303,22 @@ public abstract class ModemPeripheral
         }
     }
 
-    @Override
-    public abstract boolean equals( IPeripheral other );
-
     public IComputerAccess getComputer()
     {
         return m_computer;
     }
+
+    @Nonnull
+    @Override
+    public String getSenderID()
+    {
+        if( m_computer == null )
+        {
+            return "unknown";
+        }
+        else
+        {
+            return m_computer.getID() + "_" + m_computer.getAttachmentName();
+        }
+    }
 }

src/main/java/dan200/computercraft/shared/peripheral/modem/TileAdvancedModem.java

@@ -13,6 +13,8 @@ import net.minecraft.util.EnumFacing;
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
+import javax.annotation.Nonnull;
+
 public class TileAdvancedModem extends TileModemBase
 {
     // Statics
@@ -27,14 +29,16 @@ public class TileAdvancedModem extends TileModemBase
             m_entity = entity;
         }
 
+        @Nonnull
         @Override
         public World getWorld()
         {
             return m_entity.getWorld();
         }
 
+        @Nonnull
         @Override
-        protected Vec3d getPosition()
+        public Vec3d getPosition()
         {
             BlockPos pos = m_entity.getPos().offset( m_entity.getDirection() );
             return new Vec3d( (double)pos.getX(), (double)pos.getY(), (double)pos.getZ() );

src/main/java/dan200/computercraft/shared/peripheral/modem/TileCable.java

@@ -12,6 +12,9 @@ import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
 import dan200.computercraft.api.lua.ILuaContext;
 import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.api.network.IPacketNetwork;
+import dan200.computercraft.api.network.IPacketReceiver;
+import dan200.computercraft.api.network.Packet;
 import dan200.computercraft.api.peripheral.IComputerAccess;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.shared.common.BlockGeneric;
@@ -38,7 +41,7 @@ import java.io.File;
 import java.util.*;
 
 public class TileCable extends TileModemBase
-    implements INetwork
+    implements IPacketNetwork
 {
     private static final double MIN = 0.375;
     private static final double MAX = 1 - MIN;
@@ -65,31 +68,33 @@ public class TileCable extends TileModemBase
         }
 
         @Override
-        protected boolean isInterdimensional()
+        public boolean isInterdimensional()
         {
             return false;
         }
 
         @Override
-        protected double getTransmitRange()
+        public double getRange()
         {
             return 256.0;
         }
 
         @Override
-        protected INetwork getNetwork()
+        protected IPacketNetwork getNetwork()
         {
             return m_entity;
         }
 
+        @Nonnull
         @Override
-        protected World getWorld()
+        public World getWorld()
         {
             return m_entity.getWorld();
         }
 
+        @Nonnull
         @Override
-        protected Vec3d getPosition()
+        public Vec3d getPosition()
         {
             EnumFacing direction = m_entity.getDirection();
             BlockPos pos = m_entity.getPos().offset( direction );
@@ -233,8 +238,8 @@ public class TileCable extends TileModemBase
 
     // Members
 
-    private final Map<Integer, Set<IReceiver>> m_receivers;
-    private final Queue<Packet> m_transmitQueue;
+    private final Set<IPacketReceiver> m_receivers;
+    private final Queue<PacketWrapper> m_transmitQueue;
     
     private boolean m_peripheralAccessAllowed;
     private int m_attachedPeripheralID;
@@ -248,8 +253,8 @@ public class TileCable extends TileModemBase
     
     public TileCable()
     {
-        m_receivers = new HashMap<Integer, Set<IReceiver>>();
-        m_transmitQueue = new LinkedList<Packet>();
+        m_receivers = new HashSet<IPacketReceiver>();
+        m_transmitQueue = new LinkedList<PacketWrapper>();
         
         m_peripheralAccessAllowed = false;
         m_attachedPeripheralID = -1;
@@ -564,7 +569,7 @@ public class TileCable extends TileModemBase
             {
                 while( m_transmitQueue.peek() != null )
                 {
-                    Packet p = m_transmitQueue.remove();
+                    PacketWrapper p = m_transmitQueue.remove();
                     if( p != null )
                     {
                         dispatchPacket( p );
@@ -574,49 +579,41 @@ public class TileCable extends TileModemBase
         }
     }
 
-    // INetwork implementation
+    // IPacketNetwork implementation
 
     @Override
-    public void addReceiver( IReceiver receiver )
+    public void addReceiver( @Nonnull IPacketReceiver receiver )
     {
         synchronized( m_receivers )
         {
-            int channel = receiver.getChannel();
-            Set<IReceiver> receivers = m_receivers.get( channel );
-            if( receivers == null )
-            {
-                receivers = new HashSet<IReceiver>();
-                m_receivers.put( channel, receivers );
-            }
-            receivers.add( receiver );
+            m_receivers.add( receiver );
         }
     }
     
     @Override
-    public void removeReceiver( IReceiver receiver )
+    public void removeReceiver( @Nonnull IPacketReceiver receiver )
     {
         synchronized( m_receivers )
         {
-            int channel = receiver.getChannel();
-            Set<IReceiver> receivers = m_receivers.get( channel );
-            if( receivers != null )
-            {
-                receivers.remove( receiver );
-            }
+            m_receivers.remove( receiver );
         }
     }
 
     @Override
-    public void transmit( int channel, int replyChannel, Object payload, World world, Vec3d pos, double range, boolean interdimensional, Object senderObject )
+    public void transmitSameDimension( @Nonnull Packet packet, double range )
     {
-        Packet p = new Packet();
-        p.channel = channel;
-        p.replyChannel = replyChannel;
-        p.payload = payload;
-        p.senderObject = senderObject;
         synchronized( m_transmitQueue )
         {
-            m_transmitQueue.offer(p);
+            m_transmitQueue.offer( new PacketWrapper( packet, range ) );
+        }
+    }
+
+    @Override
+    public void transmitInterdimensional( @Nonnull Packet packet )
+    {
+        synchronized( m_transmitQueue )
+        {
+            m_transmitQueue.offer( new PacketWrapper( packet, Double.MAX_VALUE ) );
         }
     }
 
@@ -727,20 +724,27 @@ public class TileCable extends TileModemBase
         
     // Packet sending
 
-    private class Packet
+    private static class PacketWrapper
     {
-        public int channel;
-        public int replyChannel;
-        public Object payload;
-        public Object senderObject;
+        final Packet m_packet;
+        final double m_range;
+
+        private PacketWrapper( Packet m_packet, double m_range )
+        {
+            this.m_packet = m_packet;
+            this.m_range = m_range;
+        }
     }
         
-    private void dispatchPacket( final Packet packet )
+    private void dispatchPacket( final PacketWrapper packet )
     {
         searchNetwork( new ICableVisitor() {
             public void visit( TileCable modem, int distance )
             {
-                modem.receivePacket( packet, distance );
+                if( distance <= packet.m_range)
+                {
+                    modem.receivePacket( packet.m_packet, distance );
+                }
             }
         } );
     }
@@ -749,13 +753,9 @@ public class TileCable extends TileModemBase
     {
         synchronized( m_receivers )
         {
-            Set<IReceiver> receivers = m_receivers.get( packet.channel );
-            if( receivers != null )
+            for (IPacketReceiver device : m_receivers)
             {
-                for( IReceiver receiver : receivers )
-                {
-                    receiver.receiveSameDimension( packet.replyChannel, packet.payload, (double) distanceTravelled, packet.senderObject );
-                }
+                device.receiveSameDimension( packet, distanceTravelled );
             }
         }
     }

src/main/java/dan200/computercraft/shared/peripheral/modem/TileWirelessModem.java

@@ -33,14 +33,16 @@ public class TileWirelessModem extends TileModemBase
             m_entity = entity;
         }
 
+        @Nonnull
         @Override
-        protected World getWorld()
+        public World getWorld()
         {
             return m_entity.getWorld();
         }
         
+        @Nonnull
         @Override
-        protected Vec3d getPosition()
+        public Vec3d getPosition()
         {
             BlockPos pos = m_entity.getPos().offset( m_entity.getDirection() );
             return new Vec3d( (double)pos.getX(), (double)pos.getY(), (double)pos.getZ() );

src/main/java/dan200/computercraft/shared/peripheral/modem/WirelessModemPeripheral.java

@@ -7,6 +7,7 @@
 package dan200.computercraft.shared.peripheral.modem;
 
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.api.network.IPacketNetwork;
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
@@ -20,13 +21,13 @@ public abstract class WirelessModemPeripheral extends ModemPeripheral
     }
 
     @Override
-    protected boolean isInterdimensional()
+    public boolean isInterdimensional()
     {
         return m_advanced;
     }
     
     @Override
-    protected double getTransmitRange()
+    public double getRange()
     {
         if( m_advanced )
         {
@@ -56,7 +57,7 @@ public abstract class WirelessModemPeripheral extends ModemPeripheral
     }
     
     @Override
-    protected INetwork getNetwork()
+    protected IPacketNetwork getNetwork()
     {
         return WirelessNetwork.getUniversal();
     }

src/main/java/dan200/computercraft/shared/peripheral/modem/WirelessNetwork.java

@@ -6,12 +6,17 @@
 
 package dan200.computercraft.shared.peripheral.modem;
 
-import net.minecraft.util.math.Vec3d;
-import net.minecraft.world.World;
+import com.google.common.base.Preconditions;
+import dan200.computercraft.api.network.IPacketNetwork;
+import dan200.computercraft.api.network.IPacketReceiver;
+import dan200.computercraft.api.network.IPacketSender;
+import dan200.computercraft.api.network.Packet;
 
-import java.util.*;
+import javax.annotation.Nonnull;
+import java.util.HashSet;
+import java.util.Set;
 
-public class WirelessNetwork implements INetwork
+public class WirelessNetwork implements IPacketNetwork
 {
     private static WirelessNetwork s_universalNetwork = null;
 
@@ -29,67 +34,64 @@ public class WirelessNetwork implements INetwork
         s_universalNetwork = null;
     }
 
-    private Map<Integer, Set<IReceiver>> m_receivers;
+    private final Set<IPacketReceiver> m_receivers;
 
     private WirelessNetwork()
     {
-        m_receivers = new HashMap<Integer, Set<IReceiver>>();
+        m_receivers = new HashSet<IPacketReceiver>();
     }
 
     @Override
-    public synchronized void addReceiver( IReceiver receiver )
+    public synchronized void addReceiver( @Nonnull IPacketReceiver receiver )
     {
-        int channel = receiver.getChannel();
-        Set<IReceiver> receivers = m_receivers.get( channel );
-        if( receivers == null )
-        {
-            receivers = new HashSet<IReceiver>();
-            m_receivers.put( channel, receivers );
-        }
-        receivers.add( receiver );
+        Preconditions.checkNotNull( receiver, "device cannot be null" );
+        m_receivers.add( receiver );
     }
 
     @Override
-    public synchronized void removeReceiver( IReceiver receiver )
+    public synchronized void removeReceiver( @Nonnull IPacketReceiver receiver )
     {
-        int channel = receiver.getChannel();
-        Set<IReceiver> receivers = m_receivers.get( channel );
-        if( receivers != null )
+        Preconditions.checkNotNull( receiver, "device cannot be null" );
+        m_receivers.remove( receiver );
+    }
+
+    @Override
+    public synchronized void transmitSameDimension( @Nonnull Packet packet, double range )
     {
-            receivers.remove( receiver );
+        Preconditions.checkNotNull( packet, "packet cannot be null" );
+        for( IPacketReceiver device : m_receivers )
+        {
+            tryTransmit( device, packet, range, false );
         }
     }
 
     @Override
-    public synchronized void transmit( int channel, int replyChannel, Object payload, World world, Vec3d pos, double range, boolean interdimensional, Object senderObject )
+    public synchronized void transmitInterdimensional( @Nonnull Packet packet )
     {
-        Set<IReceiver> receivers = m_receivers.get( channel );
-        if( receivers != null )
+        Preconditions.checkNotNull( packet, "packet cannot be null" );
+        for (IPacketReceiver device : m_receivers)
         {
-            for( IReceiver receiver : receivers )
-            {
-                tryTransmit( receiver, replyChannel, payload, world, pos, range, interdimensional, senderObject );
-            }
+            tryTransmit( device, packet, 0, true );
         }
     }
 
-    private void tryTransmit( IReceiver receiver, int replyChannel, Object payload, World world, Vec3d pos, double range, boolean interdimensional, Object senderObject )
+    private void tryTransmit( IPacketReceiver receiver, Packet packet, double range, boolean interdimensional )
     {
-        if( receiver.getWorld() == world )
+        IPacketSender sender = packet.getSender();
+        if( receiver.getWorld() == sender.getWorld() )
         {
-            Vec3d position = receiver.getWorldPosition();
-            double receiveRange = Math.max( range, receiver.getReceiveRange() ); // Ensure range is symmetrical
-            double distanceSq = position.squareDistanceTo( pos );
-            if( interdimensional || receiver.isInterdimensional() || distanceSq <= ( receiveRange * receiveRange ) )
+            double receiveRange = Math.max( range, receiver.getRange() ); // Ensure range is symmetrical
+            double distanceSq = receiver.getPosition().squareDistanceTo( sender.getPosition() );
+            if( interdimensional || receiver.isInterdimensional() || distanceSq <= (receiveRange * receiveRange) )
             {
-                receiver.receiveSameDimension( replyChannel, payload, Math.sqrt( distanceSq ), senderObject );
+                receiver.receiveSameDimension( packet, Math.sqrt( distanceSq ) );
             }
         }
         else
         {
             if( interdimensional || receiver.isInterdimensional() )
             {
-                receiver.receiveDifferentDimension( replyChannel, payload, senderObject );
+                receiver.receiveDifferentDimension( packet );
             }
         }
     }

src/main/java/dan200/computercraft/shared/pocket/peripherals/PocketModemPeripheral.java

@@ -1,3 +1,8 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2017. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
 package dan200.computercraft.shared.pocket.peripherals;
 
 import dan200.computercraft.api.peripheral.IPeripheral;
@@ -5,11 +10,7 @@ import dan200.computercraft.shared.peripheral.modem.WirelessModemPeripheral;
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2017. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
+import javax.annotation.Nonnull;
 
 public class PocketModemPeripheral extends WirelessModemPeripheral
 {
@@ -33,14 +34,16 @@ public class PocketModemPeripheral extends WirelessModemPeripheral
         }
     }
 
+    @Nonnull
     @Override
-    protected World getWorld()
+    public World getWorld()
     {
         return m_world;
     }
 
+    @Nonnull
     @Override
-    protected Vec3d getPosition()
+    public Vec3d getPosition()
     {
         if( m_world != null )
         {

src/main/java/dan200/computercraft/shared/turtle/upgrades/TurtleModem.java

@@ -42,14 +42,16 @@ public class TurtleModem implements ITurtleUpgrade
             m_turtle = turtle;
         }
 
+        @Nonnull
         @Override
-        protected World getWorld()
+        public World getWorld()
         {
             return m_turtle.getWorld();
         }
 
+        @Nonnull
         @Override
-        protected Vec3d getPosition()
+        public Vec3d getPosition()
         {
             BlockPos turtlePos = m_turtle.getPosition();
             return new Vec3d(