Update address to UDP endpoint and delete keys on removal from DHT

eth/p2p/discoveryv5/encoding.nim

@@ -282,6 +282,11 @@ proc decodeEncrypted*(c: var Codec,
       return HandshakeError
     c.handshakes.del(key)
 
+    # For an incoming handshake, we are not sure the address in the ENR is there
+    # and if it is the real external IP, so we use the one we know from the
+    # UDP packet.
+    updateEndpoint(newNode, fromAddr)
+
     # Swap keys to match remote
     swap(sec.readKey, sec.writeKey)
     # TODO: is it safe to ignore the error here?

eth/p2p/discoveryv5/node.nim

@@ -53,6 +53,8 @@ proc `==`*(a, b: Node): bool = (a.isNil and b.isNil) or (not a.isNil and not b.i
 
 proc address*(n: Node): Address {.inline.} = n.node.address
 
+proc updateEndpoint*(n: Node, a: Address) {.inline.} = n.node.address = a
+
 proc `$`*(n: Node): string =
   if n == nil:
     "Node[local]"

eth/p2p/discoveryv5/protocol.nim

@@ -397,9 +397,11 @@ proc revalidateNode(p: Protocol, n: Node)
     if n notin p.bootstrapNodes:
       trace "Revalidation of node failed, removing node", node = $n
       p.routingTable.removeNode(n)
-      # TODO: Do we delete the shared secrets here?
-      # And if so, the current way they are stored, we might not have the key
-      # (specifically if the ENR does not have the correct address)
+      # Remove shared secrets when removing the node from routing table.
+      # This might be to direct, so we could keep these longer. But better
+      # would be to simply not remove the nodes immediatly but only after x
+      # amount of failures.
+      discard p.codec.db.deleteKeys(n.id, n.address)
 
 proc revalidateLoop(p: Protocol) {.async.} =
   try: