Basic RPC stuff in Packet and PacketDecoder for RPC service support.

node/Packet.hpp

@@ -463,7 +463,26 @@ public:
 		 *
 		 * No OK or ERROR is generated.
 		 */
-		VERB_MULTICAST_FRAME = 9
+		VERB_MULTICAST_FRAME = 9,
+
+		/* Call a plugin via RPC:
+		 *   <[1] length of function name>
+		 *   <[...] function name>
+		 *   [<[2] length of argument>]
+		 *   [<[...] argument>]
+		 *   [... additional length/argument pairs ...]
+		 *
+		 * This generates ERROR_NOT_FOUND if the specified function was not
+		 * found. Otherwise it generates an OK message. The OK message has
+		 * the same format as the request, except arguments are replaced
+		 * by results.
+		 *
+		 * This can be used to implement simple RPC. No retransmission or
+		 * other guarantees are made, so it behaves like UDP-based RPC
+		 * protocols. Plugins are typically run by supernodes and are used
+		 * to implement network lookup and other services.
+		 */
+		VERB_RPC = 10
 	};
 
 	/**