CVS commit: src/sys/net

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Sun Jul 28 14:37:59 UTC 2024

Modified Files:
        src/sys/net: if_wg.c

Log Message:
wg(4): Rework some details of internal session state machine.

This way:

- There is a clear transition between when a session is being set up,
  and when it is exposed to the data rx path (wg_handle_msg_data):
  atomic_store_release to set wgs->wgs_state to INIT_PASSIVE or
  ESTABLISHED.

  (The transition INIT_PASSIVE -> ESTABLISHED is immaterial to the
  data rx path, so that's just atomic_store_relaxed.  Similarly the
  transition to DESTROYING.)

- There is a clear transition between when a session is being set up,
  and when it is exposed to the data tx path (wg_output):
  atomic_store_release to set wgp->wgp_session_stable to it.

- Every path that reinitializes a session must go through
  wg_destroy_session via wg_put_index_session first.  This avoids
  races between session reuse and the data rx/tx paths.

- Add a log message at the time of every state transition.

Prompted by:

PR kern/55729: net/if_wg/t_misc:wg_rekey test case fails
PR kern/56252: wg(4) state machine has race conditions
PR kern/58463: if_wg does not work when idle.


To generate a diff of this commit:
cvs rdiff -u -r1.93 -r1.94 src/sys/net/if_wg.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.