New Utilities in base: vknetd and vknet

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>]

    vknetd creates a virtual bridge for any number of vitrualized
    connections and can then backfeed it all into a (possibly if_bridge'd)
    TAP interface.

    vknet can connect a local and remote machine's networks together over
    a SSH link.  It can tie into a TAP interface or /dev/vknet on both ends
    and will pass packets in both directions over the link.

    /usr/src/usr.sbin/vknetd
    /usr/src/usr.bin/vknet

    A recent HEAD kernel is required to use these utilities as they use
    the new SOCK_SEQPACKET socket type.  VKernels are also able to make
    use of vknetd sockets.

    The general idea is multi-fold.

    * First, to provide a network interconnect accessible to userland.

    * Second, to provide a secure, easy to use network virtualization
      framework.

    * And, lastly, to simplify the operation of multiple vkernels.  vknetd
      has no limitations on the number of interconnects.

    While there is some overlap with with if_bridge feature, or the use of
    IPSEC, these utilities have distinct capabilities of their own which
    can greatly simplify network glue.

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>