SDP(3)SDP(3)
NAME
sdp – secure datagram protocol
SYNOPSIS
bind -a #Espec /net
unhandled troff command .sp
/net/sdp/clone
/net/sdp/log
/net/sdp/n
/net/sdp/n/data
/net/sdp/n/control
/net/sdp/n/ctl
/net/sdp/n/rstats
/net/sdp/n/stats
/net/sdp/n/status
...
DESCRIPTION
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
services.
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:
accept file
Accept an incoming encrypted connection on
file,
typically a
data
file.
dial file
Initiate a new encrypted connection on
file,
typically a UDP
data
file.
drop permil
Randomly drop approximately one of every
permil
output packets,
thus simulating network errors.
cipher algorithm
Use ciphering
algorithm;
choices are
null,
des_56_cbc,
rc4_128,
and
rc4_256.
auth algorithm
Use authentication
algorithm;
choices are
null,
hmac_sha1_96,
and
hmac_md5_96.
comp algorithm
Use compression
algorithm;
choices are
null
and
thwack.
insecret secret
Use
secret
to decrypt incoming packets.
outsecret secret
Use
secret
to encrypt outgoing packets.
SEE ALSO
dial(2),
ip(3)
Robust Data Compression of Network Packets ,
Sean Dorward and Sean Quilan, Bell Labs, Lucent Technologies,
http://plan9.bell-labs.com/who/seanq/networkcomp.pdf.
SOURCE
/sys/src/9/port/devsdp.c