Locking Strategy

• Lock data structures

  • Don't use finer locks than required by UNIX API
    • I.e., parallel send and receive on the same socket is useful, but not parallel send on the same socket
  • Lock references to in-flight packets, not packets
  • Layers have their own locks as objects at different layers have different requirements

• Lock orders

  • Driver locks are leaf locks with respect to stack
  • Protocol drives most inter-layer activity
  • Acquire protocol locks before driver locks
  • Acquire protocol locks before socket locks
  • Avoid lock order issues via deferred dispatch