gtpu_error (BAD_VER, "packets with bad version in gtpu header")
gtpu_error (BAD_FLAGS, "packets with bad flags field in gtpu header")
gtpu_error (TOO_SMALL, "packet too small to fit a gtpu header")
+gtpu_error (UNSUPPORTED_TYPE, "packets with message type < 255 in gtpu header")
+gtpu_error (NO_ERROR_TUNNEL, "did not find an forward tunnel")