PPPOE implementation in linux

Hello All

I want to implement PPPOE for my educational project. For that I
wanted to first understand the existing implementation code flow but
I am not able to progress much on this.
Is there any way to print the debug message of the pppoe code.
I want to put some printk statement and want to understand the code
flow.

Please help me by giving some input for the following point.

1) How to invoke the pppoe code. ?

Actually I did the following to understand the above .
I removed the pppoe and pppox module from the kernel and ran the
following command
"pppoe -A eth0" and ran the tcpdump. I thought as I have removed the
modules there will not be any PPPOE packet getting generated but it
was getting generate.
I am clueless.
Please provide some inputs on how to progress from here,

Thanks.
Somenath