ipx.txt

Libnet is a cross-platform library aimed at game developers. It has an abstract high level API, whic

IPX Driver
==========

Opening Channels
----------------
    The IPX driver uses a 'virtual port' system to allow data to be 
sent to specific channels. When an IPX channel is opened using 
net_openchannel the binding parameter is used to specify what port
is associated with that channel. The bindings used are as follows :

    ""       - use the default listening port - port 0.
    NULL     - use the next avalible port.
    :'port#' - use the port number specified by 'port #'.
             - this is a decimal number.

The port is checked to see if it is bound to another channel and, if
it is, net_openchannel will return an error. When a channel is destroyed
by net_closechannel the port bound to it is freed and is avalible for
use by another channel.

Examples :

  - use the default port

    chan=net_openchannel (NET_DRIVER_IPX, "");

  - use any avalible port

    chan=net_openchannel (NET_DRIVER_IPX, NULL);

  - use a specific port (port # 5147)

    chan=net_openchannel (NET_DRIVER_IPX, ":5147");


Assigning Targets
-----------------
    In order to send data from one channel to another the sending channel
must be assigned the target address of the receiving channel. This done via
the target parameter in the net_assigntarget function. An IPX network has
a two part address, the network address and the node address. The network
address is an 8 digit hexidecimal number that is unique to the network that
your computer is on. The node address is a 12 digit hexidecimal number
that is unique to your computer. They are usually written in the form 
of 'network':'node'.

Example :

    00000000:0060674A702D

    Since libnet uses a port system for IPX we must also specify a
port number in the target address. The port is a decimal number of any
number of digits. The complete address format is written in the form
of 'network':'node':'port'.

Example :

    00000000:0060674A7034:245

    In keeping with the spirit of the Internet drivers, it is possible
to only specify part of the address and net_assigntarget will use default
values for the rest. If the network address is not included the address
of the local network for your computer will be used. If the port number
is left off, the default port number is assumed. The node address must
always be present.

Example :

  - use local network address

    0060674A702D:1

  - use default port number

    00000000:0060674A7034

  - use local network address and default port number

    0060674A7034

    If the target address is not in the right format net_assigntarget will
return an error. Care must be taken when manually providing a target
address. Very little error checking can be done so it is possible to
have net_assigntarget accept the address but have it be completely wrong.
    The 'from' address returned by net_receive is in the proper form to be
used directly by net_assigntarget.

Example :

    x = net_receive (chan, buffer2, 32, from_address);
    y = net_assigntarget (chan, from_address);


Broadcast Address
-----------------
    One feature of the IPX network is the 'broadcast address'. If the node
address is FFFFFFFFFFFF the the data is sent to all computers on the 
network, including your own. Of course, this data can only be read by the
channel with the port number you specified. This is most commonly used
by a client when it is looking for a server. It sends a 'server request'
command using the broadcast address and the default port number. The server
then sends back an acknowledgment and a proper address and port to
communicate through.


Notes
-----
  1. It is not possible for a channel to send data to itself. If the 'from'
address is the channels own address the packet is discarded. This is done
to reduce problems when using the broadcast address feature.