147 lines
2.9 KiB
Text
147 lines
2.9 KiB
Text
.TH SDP 3
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.SH NAME
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sdp \- secure datagram protocol
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.SH SYNOPSIS
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.nf
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.B bind -a #E\fIspec\fP /net
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.sp 0.3v
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.B /net/sdp/clone
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.B /net/sdp/log
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.BI /net/sdp/ n
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.BI /net/sdp/ n /data
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.BI /net/sdp/ n /control
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.BI /net/sdp/ n /ctl
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.BI /net/sdp/ n /rstats
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.BI /net/sdp/ n /stats
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.BI /net/sdp/ n /status
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\&...
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.fi
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.SH DESCRIPTION
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The
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.I sdp
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device provides the interface to the Secure Datagram Protocol (SDP).
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SDP (un)compresses and (de-)encrypts packets.
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.I Spec
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is an integer from 0 to 15 identifying a stack.
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Each stack is independent of all others:
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the only information transfer between them is via programs that
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mount multiple stacks.
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Normally a system uses only one stack.
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However multiple stacks can be used for debugging
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new networks or implementing firewalls or proxy
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services.
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.PP
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The top level directory contains a
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.B clone
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file, a
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.B log
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file, and subdirectories numbered from zero to the number of connections
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opened for this protocol.
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.PP
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Opening the
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.B clone
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file reserves a connection. The file descriptor returned from the
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.IR open (2)
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will point to the control file,
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.BR ctl ,
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of the newly allocated connection.
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Reading
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.B ctl
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returns a text
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string representing the number of the
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connection.
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Connections may be used either to listen for incoming calls
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or to initiate calls to other machines.
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.PP
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A connection is controlled by writing text strings to the associated
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.B ctl
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file.
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After a connection has been established data may be read from
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and written to
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.BR data .
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A connection can be actively established using the
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.B connect
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message (see also
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.IR dial (2)).
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A connection can be established passively by first
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using an
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.B announce
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message (see
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.IR dial (2))
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to bind to a local port and then
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opening the
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.B listen
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file (see
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.IR dial (2))
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to receive incoming calls.
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.PP
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The following control messages are supported:
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.TF "outsecret \fIsecret
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.PD
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.TP
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.BI accept " file"
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Accept an incoming encrypted connection on
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.IR file ,
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typically a
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.B data
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file.
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.TP
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.BI dial " file"
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Initiate a new encrypted connection on
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.IR file ,
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typically a UDP
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.B data
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file.
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.TP
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.BI drop " permil"
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Randomly drop approximately one of every
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.I permil
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output packets,
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thus simulating network errors.
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.TP
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.BI cipher " algorithm"
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Use ciphering
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.IR algorithm ;
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choices are
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.LR null ,
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.LR des_56_cbc ,
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.LR rc4_128 ,
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and
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.LR rc4_256 .
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.TP
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.BI auth " algorithm"
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Use authentication
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.IR algorithm ;
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choices are
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.LR null ,
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.LR hmac_sha1_96 ,
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and
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.LR hmac_md5_96 .
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.TP
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.BI comp " algorithm"
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Use compression
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.IR algorithm ;
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choices are
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.L null
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and
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.LR thwack .
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.TP
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.BI insecret " secret"
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Use
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.I secret
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to decrypt incoming packets.
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.TP
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.BI outsecret " secret"
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Use
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.I secret
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to encrypt outgoing packets.
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.
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.SH "SEE ALSO"
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.IR dial (2),
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.IR ip (3)
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.br
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.IR "Robust Data Compression of Network Packets" ,
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Sean Dorward and Sean Quilan, Bell Labs, Lucent Technologies,
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.BR http://plan9.bell-labs.com/who/seanq/networkcomp.pdf .
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.SH SOURCE
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.B /sys/src/9/port/devsdp.c
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