Implementation of Data Link Layer protocols

["Gaurav Priyolkar" <pgaurav@xxxxxxxxxxxxxx>]

Hi all,

As a part of my Computer Networks course in college I have to implement some
Data Link Layer protocols.
AFAICT, for communication between two machines, sockets cannot be used in
this case as use of TCP or UDP sockets would mean the use of a Transport or
Network Layer service respectively which is not allowed as only services
offered by lower layers may be used. So this brings me to my problem : how
to read/write data directly from/to the Physical Layer in C ? If I have
understood properly, this is what a Data Link Layer protocol is supposed to
do.
Any help and pointers would be gratefully accepted.