Way how frames are read in pppd

[Christian <crich-ml@beronet.com>]

Hi List (James:-)

I have still some issues with my litle project. Let me explain for short
what i'm doing:


Application (synchdlc) <---> Stdin/Stdout <----> pppd (synchdlc)


to ensure boundaries i have hacked pppd to add framing for stdin/stdout,
so that packets in pppd transmitted to stdout contain headers and
packets received contain headers as well.


My problem is the following:

I don't understand where exactly the  PPP(IP) frames are read in pppd
and transmitted to the master_pty. It is certainly not (only) in
read_packet. I have found out that the kernel writes correct packets
with copy_to_user to the userspace. pppd reads them and somehow
transmits them to the master_fd. At this point the boundaries got lost.

I have tried to read the pppd code for a while, but i think i can't see
the forest anymore because of all the trees.

I would apreciate any help.

cheers,

Christian