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introduction to linux kernel tcp/ip ptocotol stack

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monad bobo
monad bobo

This document provides an introduction and overview of the networking code in the Linux kernel source tree. It discusses the different layers including link (L2), network (L3), and transport (L4) layers. It describes the input and output processing, device interfaces, traffic directions, and major developers for each layer. Config and benchmark tools are also mentioned. Resources for further learning about the Linux kernel networking code are provided at the end.

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Introduction to Linux Kernel TCP/IP procotol stack µñÁº ºËÐÄϵͳ·þÎñÆ÷ƽ̨×é diaoliang@taobao.com simohayha.bobo@gmail.com http://www.pagefault.info 2011/01/15
Agenda Introduction Networking code in the Linux kernel tree L2 (Link Layer) L3 (Network Layer) L4 (Transport Layer) Config and benchmark tools Resource
Introduction Source http://git.kernel.org/ net-next-2.6 and net-2.6 Developer Alan Cox, David Miller, Eric Dumazet, Patrick Mchardy etc. Traffic directions input , forward and output Layer L2(Link Layer)/L3(Network Layer)/L4(Transport Layer) Device interface PCI/PCI-E
Networking code in the Linux kernel tree Net-Kernel source tree
Big picture
Link layer Frame type 802.3/802.2/802.2-SNAP/Ethernet Input Driver NAPI Poll + Interrupt Soft interrupt GRO feed packet to network stack RPS/RFS make steer in SMP Protocol handler use eth_type_trans Packet_type list
Link layer Output Traffic Control Soft interrupt Transmit SKB Scatter/Gather DMA Free skb XPS multiqueue avoid cache line bouncing improve locality Bridge Virtual device, must bind one or more real device Spanning Tree Protocol
Link Layer bigmap
Network Layer(IP) Input Protocol handler net_protocol array defragment Hashtable Each IP packet being defragmented save in a list stored in kernel memory until they are totally processed Output fragment MTU Scatter/Gather IO udp neighboring
Network Layer(IP) Forward process ip option igonore defragmentation Router Alert option Route Forwarding Information Base(routing table) cache Netfilter HOOK point NF_IP_LOCAL_OUT/ NF_IP_LOCAL_IN etc.. Management Long-living IP peer information AVL tree IP statistics per cpu data ipstats_mib /proc/net/snmp
Network Layer Bigmap
Transport Layer (tcp) Init bind callback (sock_create) Three handshrek accept queue syn table create new socket fd and change state Manage socket inet_ehash_bucket TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE inet_bind_hashbucket local binding port info listening_hash socket in TCP_LISTEN state
Transport Layer (tcp) Output Tcp push Congestion control state transition congestion windows packet count Input fast path and slow path Interrupt context/ Process context sk_backlog/receive_queue/prequeue Tcp state transition Kernel control Timer Retransmit/keep-alive/time-wait etc
TCP Bigmap
Config and Benchmark Tools Ethtool offload fetures Benchmark and test tools Netperf/pktgen Mpstat/tcpstat Proc FileSystem /proc/net /proc/sys/net ipv4 core Sys FileSystem /sys/class/net/ethx
Resource http://kernelnewbies.org http://kernel.org http://www.kernelplanet.org https://lkml.org http://vger.kernel.org/vger-lists.html http://www.pagefault.info/?tag=kernel

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introduction to linux kernel tcp/ip ptocotol stack

  • 1. Introduction to Linux Kernel TCP/IP procotol stack µñÁº ºËÐÄϵͳ·þÎñÆ÷ƽ̨×é diaoliang@taobao.com simohayha.bobo@gmail.com http://www.pagefault.info 2011/01/15
  • 2. Agenda Introduction Networking code in the Linux kernel tree L2 (Link Layer) L3 (Network Layer) L4 (Transport Layer) Config and benchmark tools Resource
  • 3. Introduction Source http://git.kernel.org/ net-next-2.6 and net-2.6 Developer Alan Cox, David Miller, Eric Dumazet, Patrick Mchardy etc. Traffic directions input , forward and output Layer L2(Link Layer)/L3(Network Layer)/L4(Transport Layer) Device interface PCI/PCI-E
  • 4. Networking code in the Linux kernel tree Net-Kernel source tree
  • 6. Link layer Frame type 802.3/802.2/802.2-SNAP/Ethernet Input Driver NAPI Poll + Interrupt Soft interrupt GRO feed packet to network stack RPS/RFS make steer in SMP Protocol handler use eth_type_trans Packet_type list
  • 7. Link layer Output Traffic Control Soft interrupt Transmit SKB Scatter/Gather DMA Free skb XPS multiqueue avoid cache line bouncing improve locality Bridge Virtual device, must bind one or more real device Spanning Tree Protocol
  • 9. Network Layer(IP) Input Protocol handler net_protocol array defragment Hashtable Each IP packet being defragmented save in a list stored in kernel memory until they are totally processed Output fragment MTU Scatter/Gather IO udp neighboring
  • 10. Network Layer(IP) Forward process ip option igonore defragmentation Router Alert option Route Forwarding Information Base(routing table) cache Netfilter HOOK point NF_IP_LOCAL_OUT/ NF_IP_LOCAL_IN etc.. Management Long-living IP peer information AVL tree IP statistics per cpu data ipstats_mib /proc/net/snmp
  • 12. Transport Layer (tcp) Init bind callback (sock_create) Three handshrek accept queue syn table create new socket fd and change state Manage socket inet_ehash_bucket TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE inet_bind_hashbucket local binding port info listening_hash socket in TCP_LISTEN state
  • 13. Transport Layer (tcp) Output Tcp push Congestion control state transition congestion windows packet count Input fast path and slow path Interrupt context/ Process context sk_backlog/receive_queue/prequeue Tcp state transition Kernel control Timer Retransmit/keep-alive/time-wait etc
  • 15. Config and Benchmark Tools Ethtool offload fetures Benchmark and test tools Netperf/pktgen Mpstat/tcpstat Proc FileSystem /proc/net /proc/sys/net ipv4 core Sys FileSystem /sys/class/net/ethx
  • 16. Resource http://kernelnewbies.org http://kernel.org http://www.kernelplanet.org https://lkml.org http://vger.kernel.org/vger-lists.html http://www.pagefault.info/?tag=kernel