Tutorial for creation of packet in Linux kernel

Question

I'm trying to understand the journey a piece of data undergoes through the linux kernel from application layer onto the wire in detail through the kernel. Does anyone know of a good place to start or a good tutorial?

Answer 1

The book "Understanding the Linux Kernel" definitely has some answers for you

Answer 2

I don't really know, but the big picture is something like this:

First thing: Application -> Kernel (trough the socket, resulted from binding to a port)

Inside the Kernel: NetFilter <=> TCP/IP Stack -> NIC's driver

After the kernel: NIC's Firmware -> Wire

Links:

• http://en.wikipedia.org/wiki/Netfilter
• http://en.wikipedia.org/wiki/Linux_kernel#Architecture

Later: After a bit of googling, look at what I've found:

• http://www.ecsl.cs.sunysb.edu/elibrary/linux/network/LinuxKernel.pdf (it's a bit old this document, as it seems to describe the 2.4 kernel but may be helpful)
• http://vger.kernel.org/~davem/ (has some interesting links)
• http://www.linuxhq.com/lkprogram.html#networking

Answer 3

The best online references are

• Net:Kernel Flow
• Anatomy of the Linux networking stack

but if you are looking for a more in depth dead-tree reference, I'd recommend Understanding Linux Network Internals