This may sound like a very noob question. I'm trying to implement a UDP-based protocol in the linux kernel. I was following the UDPLite protocol implementation as a reference.

Step 1

I created a new_protocol.c in net/ipv4/
This file has a function
void _init protocol_init(void){*Code here*}

I also used
#include "udp_impl.h"
in this file as I was using some functions from the UDP protocol

Step 2

I modified the file net/ipv4/udp_impl.h to include net/new_protocol.h

Step 3

I created the file include/net/new_protocol.h where I defined the function
void protocol_init(void);

Step 4

Finally, I called this init function in net/ipv4/af_inet.c. Also, I gave an include statement in this file (af_inet.c) for net/new_protocol.h

Now when I try to build the kernel, I get an error saying
undefined reference to `protocol_init()'

What am I missing here? Is my way of including header files incorrect? Do I need to include some info in the makefile to pick up the new net/ipv4/protocol.c?

It's easier to maintain a kernel module if you build it separately from the rest of the kernel, as described here:

http://lxr.free-electrons.com/source...les.txt?v=3.10

I figured out that I hadn't updated the Makefile in net/ipv4.
As an aside, compiling kernel may not take so long if CCache tool is used with make.