[DGD] Writing an external network daemon

[Felix A. Croes]

bart at wotf.org wrote:

>[...]
> > UDP is only supported as an addition to an existing (binary) connection;
> > it functions as a kind of out-of-band channel and communicates with the
> > same connection object.  On the server side, the UDP port is the 
> > same as the TCP port; on the client side, the ports can be different.
>
> Does it accept udp packets from other ips then the one that it has a binary
> connection with?

The IP number has to match, as well.


>[...]
> open_datagram() doesn't take any arguments so I assume the client port is
> known internally, but not exposed to the lpc layer? (its not really needed
> there at any rate for all I can tell, tho it might be desirable to know I can
> imagine)

The client port is hidden from the LPC layer.  Only the IP number,
which is the same for both TCP and UDP on a connection, is known.


> > UDP packets are passed on to the connection object as they are
> > received.  DGD makes no attempt at packet reassembly or preventing
> > out-of-order reception.  Only one UDP packet can be sent by each
> > connection object per execution round.
>
> This also applies to the network package, but it extends this with a
> datagram_done() callback similar to message_done() for telnet and binary tcp
> connections to make buffering in lpc easy and similar to tcp buffering.

I can see why you would want it to be similar, but since there is no
flow control for UDP, there is no need for the callback.

Regards,
Felix Croes