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58 lines
1.2 KiB
Markdown
58 lines
1.2 KiB
Markdown
# vTunnel - Protocol
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vTunnel uses a (relatively) simple protocol to communicate over TCP, encoding packets as strings and adding a tag. The protocol is as follows:
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```
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<2 bytes length of packet><1 byte number of segments><2 bytes length of segment><1 byte type><data>
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```
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2-byte lengths are encoded as big-endian, as in the following code from interminitel.lua:
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```
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function imt.to16bn(n)
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return string.char(math.floor(n/256))..string.char(math.floor(n%256))
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end
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```
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Each packet can have up to 255 segments, or indeed zero.
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So, to encode a packet with the field "Hello, world!":
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```
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0 \0
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17 \17 first two bytes are length
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1 \1 third is number of segments
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0 \0
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13 \13 length of first segment
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1 \1 type of first segment (string)
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72 H data from here
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101 e
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108 l
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108 l
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111 o
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44 ,
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32
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119 w
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111 o
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114 r
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108 l
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100 d
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33 !
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```
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## Types
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1. string
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2. number
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3. boolean
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4. nil
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## Defaults
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By default, the bridge server:
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- uses port 4096, as Minitel does on OpenComputers networks
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- drops clients after 60 seconds of inactivity
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This can be configured by appending a port number and timeout (in seconds) to the command you use to launch the bridge.
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