Plan 9 networking

Using the /net filesystem

You can make network connections just by interacting with files in /net.

Connecting via TCP

First you could create a new socket by reading the contents of /net/tcp/clone, then one would write to the socket in /net/tcp/$socketno/ctl, to connect to some host, and then read/write to /net/tcp/$socketno/data.

Apparently, one can’t close the /net/tcp/clone file after reading from it or the connection will be closed, and this code keeps it open by piping it to a file descriptor and not closing it until we’re done.

I don’t know what the file descriptor “5” is.

<[5] /net/tcp/clone {   # Pipe the /net/tcp/clone file to fd 5.
            # Don't close it until this block is closed?
    netdir = '/net/tcp/' ^ `{cat /fd/5}

    # Connect to some host 9.9.9.9 on port 19
    echo connect 9.9.9.9!19 > $netdir/ctl || echo cant connect
    cat $netdir/data
}

This task is eased by the aux/trampoline tool trampoline(8), and by the dial(2) C function.

aux/listen1

aux/listen

/bin/service/

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