TUTORIALS 》 Linux Kernel Internals :: Implementing a Linux Kernel System Call

Here is a code-walk of a git-hub source submitted by a viewer Sekhar Pariga, which is a Multi-client TCP Server with pthreads Mutex synchronized. Basically it is a Directory Listing Server, that serves ls, cd, pwd of directory functions to connecting TCP clients which are remotely (locally) executed by the server. Server is implemented using multi-thread pthread library, to serve multiple clients simultaneously. Server keeps the each accepted client session details in the queue data structure. Client session queue contains each clients socket-fd and present working directory as a queue node.

Here is my sample Kernel Module to drop packets (i.e sk_buff instance) captured via netfilter hooks. When you want to drop packets in your custom netfilter hooks make sure you never do a manual kfree_skb(skb) API call. Since it is anyway performed once the flow of the code moves out of your kernel module netfilter hook. All you need to do is to return NF_DROP to drop gracefully the desired packet. Here is my detailed video and a sample Linux Kernel module.

Here is a small list of Linux (Kernel, Linux Users Group) and Open-Source Communities across the world.