Vnddmgr is alternative network device driver similar to Linux TAP (namely network tap) which simulates a link layer device and it operates with layer 2 packets like Ethernet frames.
Vnddmgr is part of TVPN solution and it is used for creating a network bridge.
Packets sent by an operating system via a Vnddmgr virtual devices are delivered to a user-space program which attaches itself to the device.
A user-space program may also pass packets into a vnddmgr device.
In this case the vnddmgr device delivers (or "injects") these packets to the operating-system network stack thus emulating their reception from an external source.
Download TinyVPN source code which include vnddmgr driver