sdp – secure datagram protocol|
bind –a #Espec /net |
The sdp device provides the interface to the Secure Datagram Protocol
(SDP). SDP (un)compresses and (de–)encrypts packets. Spec is an
integer from 0 to 15 identifying a stack. Each stack is independent
of all others: the only information transfer between them is via
programs that mount multiple stacks. Normally a
system uses only one stack. However multiple stacks can be used
for debugging new networks or implementing firewalls or proxy
The top level directory contains a clone file, a log file, and subdirectories numbered from zero to the number of connections opened for this protocol.
Opening the clone file reserves a connection. The file descriptor returned from the open(2) will point to the control file, ctl, of the newly allocated connection. Reading ctl returns a text string representing the number of the connection. Connections may be used either to listen for incoming calls or to initiate calls to other machines.
A connection is controlled by writing text strings to the associated ctl file. After a connection has been established data may be read from and written to data. A connection can be actively established using the connect message (see also dial(2)). A connection can be established passively by first using an announce message (see dial(2)) to bind to a local port and then opening the listen file (see dial(2)) to receive incoming calls.
The following control messages are supported:
Robust Data Compression of Network Packets, Sean Dorward and Sean Quilan, Bell Labs, Lucent Technologies, http://plan9.bell–labs.com/who/seanq/networkcomp.pdf.