Linux networking stack

http://www.6test.edu.cn/~lujx/linux_networking/index.html?page=0131777203_ch17lev1sec4.html

http://www.ecsl.cs.sunysb.edu/elibrary/linux/network/LinuxKernel.pdf : good link

http://e-university.wisdomjobs.com/linux/chapter-208-277/receiving-data-in-the-transport-layer-udp-and-tcp.html

http://hsnlab.tmit.bme.hu/twiki/pub/Targyak/Mar11Cikkek/Network_stack.pdf : very good