Linux Kernel Network Stack Internals

High-Performance Networking & Cloud-Native · 30 illustrated lessons (text/HTML)

Outcomes

• Trace a packet from the NIC to the socket and back
• Read TCP connection and data-path code with confidence
• Debug the stack with tracing and tune its performance

Where we teach this

• NET-101 · Linux Network Stack Architecture & Sockets live cohort

The lessons

Every lesson in this curriculum, in the order we teach it.

• 1Learning roadmap
• 2The network subsystem architecture
• 3The network device driver model
• 4Packet reception (top half)
• 5Packet reception (bottom half)
• 6The socket buffer (sk_buff)
• 7The network stack entry point: eth_type_trans, layer-2 processing and packet routing decisions
• 8Link-layer protocol processing
• 9Network-layer protocol entry
• 10The IP routing subsystem explained
• 11IP local delivery
• 12IP forwarding
• 13Transport-layer protocol dispatch
• 14TCP protocol overview
• 15TCP connection management: the three-way handshake in the kernel
• 16TCP data reception: tcp_v4_rcv, receive and out-of-order queues, ACK generation and sending
• 17TCP data transmission: core mechanisms
• 18TCP congestion control
• 19UDP processing
• 20The socket-layer interface in depth
• 21System calls: send and sendmsg
• 22System calls: recv and recvmsg
• 23Netfilter and iptables in depth
• 24Connection tracking (conntrack)
• 25Network namespaces
• 26Virtual network devices in depth
• 27XDP fundamentals
• 28Network performance tuning
• 29Course overview
• 30Summary and outlook