Cleaned up ProxyArpManager code by creating an interface through which it can request information about the L3 configuration (IP addresses, ports, etc)
diff --git a/src/main/java/net/floodlightcontroller/packet/IPv4.java b/src/main/java/net/floodlightcontroller/packet/IPv4.java
index 01f886d..85f21ca 100644
--- a/src/main/java/net/floodlightcontroller/packet/IPv4.java
+++ b/src/main/java/net/floodlightcontroller/packet/IPv4.java
@@ -31,6 +31,7 @@
  *
  */
 public class IPv4 extends BasePacket {
+	public static final int ADDRESS_LENGTH = 4;
     public static final byte PROTOCOL_ICMP = 0x1;
     public static final byte PROTOCOL_TCP = 0x6;
     public static final byte PROTOCOL_UDP = 0x11;