Linux kernel network drivers

Linux kernfags,

Writing kernel network device driver (with the help of LDD3).  I want to piggyback onto an existing interface (e.g. eth0), and pre-parse the data coming across the network interface for specific values, and if they match, handle them myself, otherwise, pass them onto the normal network driver for my NIC.  In LDD3, the process for creating one's own network interface is described, but not the process for just riding on top of another one, without implementing the underlying implementation of a full network card driver.  Also, doing this from kernel space is a must, so pcap, etc. won't cut it.

HALP PLOX

Yes, I have.  That's what I described, and what I am building.  It's the internal kernel methods to do so, and which I was looking for a knowledgeable kernel developer to provide advice about, which was the reason behind my post.