[linux-dvb] Re: Question about dvb_net

[Johannes Stezenbach <js@linuxtv.org>]

Luca Abeni wrote:
> if I understand correctly, it is currently possible to receive only a
> single PID per dvbx_y network interface... Is this correct?

Yes.

> Since I need to route multicast traffic arriving on more than 1 PID, I
> will try to modify dvb_net.c to receive more than 1 PID per network
> interface. But before starting to modify the code, I have some
> questions:
> 1) Why has dvb_net been designed to receive only 1 PID per network
> interface? Because it's simpler, or because of some other reason? (I am
> asking simply because I do not want to overlook some problems from the
> beginning)

If you join multicast groups on that interface, how do you know
which PID to set the filter on if you have multiple PIDs per network
device? Set the filter on all of them?

> 2) Is there any interest in removing such a limitation?

If you have an answer to the question above: Yes.

I'm not sure about this, but: You don't need to use dvb_net
at all, you could have a userspace program that sets section filters
and pumps received network packets into the kernel via TUN/TAP.
The downside of this approach might be a higher overhead because
the data is copied multiple times, but IMHO for PCs it is
negligible, only for embedded devices it might be a problem.


Johannes