OC-Minitel

Easy-to-implement networking protocol for OpenComputers

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Minitel for OpenOS

This package includes the Minitel daemon, in etc/rc.d/minitel.lua, and the minitel library for using minitel, in usr/lib/minitel.lua.

Minitel daemon

Installation

With OPPM

1. Run oppm install minitel-util - this will install both the Minitel utilities and pull in the Minitel daemon as a dependency.
2. Run mtcfg

This will walk you through setting up Minitel.

Manual

1. Place minitel.lua into /etc/rc.d
2. Place your hostname into /etc/hostname
3. Run rc minitel enable; rc minitel start

Configuration

The minitel daemon keeps a settings file in /etc/minitel.cfg, which is loaded on start. This can be edited directly and the daemon restarted, or settings can be changed from the command line.

To change a setting, one invokes:

rc minitel set <option> <value>

Available settings

• port: the physical port the protocol runs over
• pctime: the amount of time packets are kept in the packet cache
• retry: how many seconds between resend attempts of reliable packets
• rctime: How long items are kept in the routing cache
• retrycount: how many attempts to resend should be made
• route: whether to forward packets
• debug: whether to output debugging info to the display

In addition, one can invoke to get large amounts of debug output, *rc minitel set_route * to add a static route, and *rc minitel del_route * to delete a static route.

Events

The Minitel daemon handles both sending and receiving packets, via events. There are four types of events used:.

net_msg, from, port, data

This event is triggered when the Minitel daemon receives a data (type 0 or 1) packet.

net_ack, packet ID

This event is triggered when the Minitel daemon receives an acknowledgement (type 2) packet.

net_broadcast, from, port, data

This event is triggered when the Minitel daemon receives a broadcast (addressed to ‘~’) packet of type 1 or 2.

net_send, packet type, to, port, data, packet ID

This event can be queued (with computer.pushSignal) to manually build packets. While you should never need to use this, it may be useful for certain edge cases.

Minitel library

The minitel library provides an easy way of interacting with the minitel daemon, and implements higher-level features of the stack.

API

Layer 3

minitel.genPacketID() - returns a string of random data

minitel.usend(host, port, data, pid) - Sends an unreliable packet to host on port containing data, optionally with the packet ID pid.

minitel.rsend(host, port, data, block) - Sends a reliable packet to host on port containing data. If block is true, don’t wait for a reply.

Layer 4

minitel.send(host, port, data) - Sends data reliably and in order to host on port.

Layer 5

minitel.open(to,port) - Establishes a stream to host on port and returns a stream object

minitel.listen(port) - Waits for another node to establish a stream, and returns the stream object.

Stream objects

stream:write(data) - Sends data to the node at the other end of the stream

stream:read(length) - Reads data from the stream, in several modes:

• If you pass length as a number, up to length bytes will be read from the socket.
• If length == “*a”, everything in the buffer will be returned.
• If you pass length as any other string, and there is length in the buffer somewhere, the data up to length in the buffer will be returned. This ignores all but the first character.
• If length is nil, it will read up until the next newline.

stream:close() - Ends the stream and prevents further writing.

Variables

minitel.mtu = 4096 - The maximum length of the data portion of a packet for minitel.send

minitel.streamdelay = 60 - The time, in seconds, minitel.open will wait for a response while trying to establish a connection.

minitel.minport = 32768 - The lowest port minitel.listen will allocate to a new connection.

minitel.maxport = 65535 - The highest port minitel.listen will allocate to a new connection.