RE: About Connection between PPP and linux Sockets

[Marcel Holtmann <marcel@holtmann.org>]

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Hi Zhenhua,

> >> I have a little question just as the title said?
> >> In Ofono how to connect PPP to Linux socket, when we receive packet
> >> from network, how the packet go through the kernel to application？
> >> 
> >> modem -->PPP-->? --> linux kernel(network part)--> socket -->
> >> application? 
> > 
> > it is more like this:
> > 
> > modem -> TTY -> PPP -> TUN/TAP -> Kernel Net-Stack -> socket ->
> > application. 
> > 
> > With the TTY being in kernel, the PPP being in userspace, and TUN/TAP
> > etc. begin in the kernel again.
> > 
> > A future enhancement is to use the kernel PPP layer, but we haven't
> > gotten there yet.
> 
> I am interested to know how could we use kernel PPP layer instead of gatppp. Shall we add this item into our TODO?

the kernel PPP line discipline can be used and then LCP and IPCP will be
spoken via a side channel to the kernel. And all the packet handling is
done by the kernel itself via the TTY line discipline. It is a bit more
work than just using a TUN/TAP device. And of course it only works in
real TTYs. Not on the GIOChannel that you get from GAtMux.

Regards

Marcel