Custom stack: it goes to 11

I’m writing up my Shmoocon preso as a series of blogposts. Today I’m going to talk about custom network stacks.

The way network stacks work today is to let the kernel do all the heavy lifting. It starts with kernel drivers for Ethernet cards, which passes packets to the kernel’s TCP/IP stack. Upon the reception, the packet must make an arduous climb up the network stack until it finally escapes to user-mode. (User-mode is where applications run).