Background: Network Stack Architecture

• Socket abstraction: exposed to applications and kernel consumers (NFS, SMB, AIO, ...)

• Network interface abstraction + BPF

• “Protocols”, such as TCP/IP, UDP/IP, et al.

• Routing, bridging/forwarding, filtering engines

  • Also IPSEC, tunneling, compression, ...

• Netgraph extensible network framework

• Network interface device drivers

• Mbuf allocator and utilities