Fix P2P receiver not invalidating target on netsplit

src/main/kotlin/net/shadowfacts/phycon/block/DeviceBlockEntity.kt

@@ -19,6 +19,7 @@ import net.shadowfacts.phycon.api.util.MACAddress
 import net.shadowfacts.phycon.frame.ARPQueryFrame
 import net.shadowfacts.phycon.frame.ARPResponseFrame
 import net.shadowfacts.phycon.frame.BasePacketFrame
+import net.shadowfacts.phycon.frame.NetworkSplitFrame
 import net.shadowfacts.phycon.packet.*
 import net.shadowfacts.phycon.util.NetworkUtil
 import java.lang.ref.WeakReference
@@ -75,6 +76,7 @@ abstract class DeviceBlockEntity(type: BlockEntityType<*>, pos: BlockPos, state:
 		when (frame) {
 			is ARPQueryFrame -> handleARPQuery(frame)
 			is ARPResponseFrame -> handleARPResponse(frame)
+			is NetworkSplitFrame -> handleNetworkSplit()
 			is PacketFrame -> {
 				if (frame.packet.destination.isBroadcast || frame.packet.destination == ipAddress) {
 					doHandlePacket(frame.packet)
@@ -107,6 +109,11 @@ abstract class DeviceBlockEntity(type: BlockEntityType<*>, pos: BlockPos, state:
 		packetQueue.removeAll(toRemove)
 	}
 
+	protected open fun handleNetworkSplit() {
+		arpTable.clear()
+		cachedDestination = null
+	}
+
 	override fun sendPacket(packet: Packet) {
 		if (packet.destination.isBroadcast) {
 			send(BasePacketFrame(packet, macAddress, MACAddress.BROADCAST))
@@ -140,6 +147,7 @@ abstract class DeviceBlockEntity(type: BlockEntityType<*>, pos: BlockPos, state:
 
 	override fun cableDisconnected() {
 		cachedDestination = null
+		handleNetworkSplit()
 	}
 
 	open fun tick() {

src/main/kotlin/net/shadowfacts/phycon/block/cable/CableBlock.kt

@@ -2,8 +2,10 @@ package net.shadowfacts.phycon.block.cable
 
 import net.fabricmc.fabric.api.`object`.builder.v1.block.FabricBlockSettings
 import net.minecraft.block.*
+import net.minecraft.block.entity.BlockEntity
 import net.minecraft.entity.player.PlayerEntity
 import net.minecraft.item.ItemPlacementContext
+import net.minecraft.item.ItemStack
 import net.minecraft.state.StateManager
 import net.minecraft.state.property.EnumProperty
 import net.minecraft.util.ActionResult
@@ -200,11 +202,13 @@ class CableBlock(
 	override fun onBreak(world: World, pos: BlockPos, state: BlockState, player: PlayerEntity) {
 		super.onBreak(world, pos, state, player)
 		if (!world.isClient) {
-			// notify devices on either end that the connection was broken (i.e., unset the cached receivers)
-			val connectedSides = getNetworkConnectedSides(state, world, pos)
-			for (side in connectedSides) {
-				val dest = NetworkUtil.findConnectedInterface(world, pos, side)
-				dest?.cableDisconnected()
+			world.server?.execute {
+				// notify devices on either end that the connection was broken (i.e., unset the cached receivers)
+				val connectedSides = getNetworkConnectedSides(state, world, pos)
+				for (side in connectedSides) {
+					val dest = NetworkUtil.findConnectedInterface(world, pos, side)
+					dest?.cableDisconnected()
+				}
 			}
 		}
 	}

src/main/kotlin/net/shadowfacts/phycon/block/netswitch/SwitchBlockEntity.kt

@@ -17,6 +17,7 @@ import net.shadowfacts.phycon.api.frame.PacketFrame
 import net.shadowfacts.phycon.api.util.IPAddress
 import net.shadowfacts.phycon.api.util.MACAddress
 import net.shadowfacts.phycon.frame.BasePacketFrame
+import net.shadowfacts.phycon.frame.NetworkSplitFrame
 import net.shadowfacts.phycon.init.PhyBlockEntities
 import net.shadowfacts.phycon.packet.ItemStackPacket
 import net.shadowfacts.phycon.util.NetworkUtil
@@ -66,12 +67,12 @@ class SwitchBlockEntity(pos: BlockPos, state: BlockState): BlockEntity(PhyBlockE
 			PhysicalConnectivity.NETWORK_LOGGER.debug("{} ({}, {}) forwarding {} to side {}", this, fromItf.side, fromItf.macAddress, frame, dir)
 			interfaceForSide(dir).send(frame)
 		} else {
-			PhysicalConnectivity.NETWORK_LOGGER.debug("{} ({}, {}) flooding {}", this, fromItf.side, fromItf.macAddress, frame)
 			flood(frame, fromItf)
 		}
 	}
 
-	private fun flood(frame: EthernetFrame, source: Interface) {
+	private fun flood(frame: EthernetFrame, source: SwitchInterface) {
+		PhysicalConnectivity.NETWORK_LOGGER.debug("{} ({}, {}) flooding {}", this, source.side, source.macAddress, frame)
 		for (itf in interfaces) {
 			if (source == itf) continue
 			itf.send(frame)
@@ -86,6 +87,16 @@ class SwitchBlockEntity(pos: BlockPos, state: BlockState): BlockEntity(PhyBlockE
 				}
 	}
 
+	private fun cableDisconnected(itf: SwitchInterface) {
+		macTable.entries.filter {
+			it.value == itf.side
+		}.forEach {
+			macTable.remove(it.key)
+		}
+		destinationCache[itf.side.ordinal] = null
+		flood(NetworkSplitFrame(itf.macAddress), itf)
+	}
+
 	fun tick() {
 		packetsHandledThisTick = 0
 
@@ -164,7 +175,7 @@ class SwitchBlockEntity(pos: BlockPos, state: BlockState): BlockEntity(PhyBlockE
 		}
 
 		override fun cableDisconnected() {
-			switch.get()?.destinationCache?.set(side.ordinal, null)
+			switch.get()?.cableDisconnected(this)
 		}
 	}
 

src/main/kotlin/net/shadowfacts/phycon/block/p2p/P2PReceiverBlockEntity.kt

@@ -12,9 +12,11 @@ import net.shadowfacts.phycon.api.packet.Packet
 import net.shadowfacts.phycon.api.util.IPAddress
 import net.shadowfacts.phycon.block.DeviceBlockEntity
 import net.shadowfacts.phycon.block.FaceDeviceBlock
+import net.shadowfacts.phycon.frame.NetworkSplitFrame
 import net.shadowfacts.phycon.init.PhyBlockEntities
 import net.shadowfacts.phycon.packet.*
 import net.shadowfacts.phycon.util.ClientConfigurableDevice
+import java.lang.ref.WeakReference
 
 /**
  * @author shadowfacts
@@ -50,17 +52,21 @@ class P2PReceiverBlockEntity(pos: BlockPos, state: BlockState): DeviceBlockEntit
     var clientObserver: (() -> Unit)? = null
 
     private var isFirstTick = true
-    // todo: need some way of removing this when there's no network path to the p2p interface
-    private var targetInventory: Storage<ItemVariant>? = null
+    private var targetInventory: WeakReference<Storage<ItemVariant>>? = null
 
     override fun handle(packet: Packet) {
         when (packet) {
             is PongPacket -> if (packet.source == target) status = Status.OK
-            is ReadItemStoragePacket -> targetInventory = packet.inventory
+            is ReadItemStoragePacket -> targetInventory = WeakReference(packet.inventory)
             is DeviceRemovedPacket -> if (packet.source == target) targetInventory = null
         }
     }
 
+    override fun handleNetworkSplit() {
+        super.handleNetworkSplit()
+        targetInventory = null
+    }
+
     override fun tick() {
         super.tick()
 
@@ -74,10 +80,10 @@ class P2PReceiverBlockEntity(pos: BlockPos, state: BlockState): DeviceBlockEntit
         if (target == null) {
             return null
         }
-        if (targetInventory == null) {
+        if (targetInventory?.get() == null) {
             sendPacket(RequestInventoryPacket(RequestInventoryPacket.Kind.SIDED, ipAddress, target!!))
         }
-        return targetInventory
+        return targetInventory?.get()
     }
 
     private fun updateStatus() {

src/main/kotlin/net/shadowfacts/phycon/block/terminal/AbstractTerminalBlockEntity.kt

@@ -18,6 +18,7 @@ import net.shadowfacts.phycon.api.packet.Packet
 import net.shadowfacts.phycon.api.util.IPAddress
 import net.shadowfacts.phycon.block.DeviceBlockEntity
 import net.shadowfacts.phycon.component.*
+import net.shadowfacts.phycon.frame.NetworkSplitFrame
 import net.shadowfacts.phycon.packet.*
 import net.shadowfacts.phycon.util.NetworkUtil
 import java.lang.ref.WeakReference
@@ -69,6 +70,11 @@ abstract class AbstractTerminalBlockEntity(type: BlockEntityType<*>, pos: BlockP
 		return null
 	}
 
+	override fun handleNetworkSplit() {
+		super.handleNetworkSplit()
+		inventoryCache.clear()
+	}
+
 	override fun handle(packet: Packet) {
 		when (packet) {
 			is ReadGroupedInventoryPacket -> handleReadInventory(packet)

src/main/kotlin/net/shadowfacts/phycon/frame/NetworkSplitFrame.kt

@@ -0,0 +1,8 @@
+package net.shadowfacts.phycon.frame
+
+import net.shadowfacts.phycon.api.util.MACAddress
+
+/**
+ * @author shadowfacts
+ */
+class NetworkSplitFrame(source: MACAddress): BaseFrame(source, MACAddress.BROADCAST)