# 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 <hostname> <local_modem> <remote_modem>* to add a static route, and *rc minitel del_route <hostname>* 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, instead return the packet ID.

#### 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.
