mac80211: Implement mesh synchronization framework

This patch adds MBSS extensible synchronization framework (Sec.
13.13.2 of IEEE Std. 802.11-2012).

The framework is implemented via an ops table which defines the
following functions:

    rx_bcn_presp() - this is called every time a mesh beacon is
received.
    adjust_tbtt() - this is called immediately before a beacon is about
to be transmitted.

The default neighbor offset synchronization defined in the standard is
implemented.  We also provide template functions for vendor specific
methods.

When neighbor offset synchronization is active (which is the default)
mesh neighbors in the same MBSS will track timing offsets to each other
and compensate clock drift.

In our tests we observed that this mesh synchronization implementation
successfully corrected drifts between stations of ~2PPM while
introducing a jitter of ~20us.

It is also possible to test this framework on mac80211_hwsim simulated
phys to see how it behaves under different topologies, over poor links,
etc.

Signed-off-by: Marco Porsch <marco.porsch@s2005.tu-chemnitz.de>
Signed-off-by: Pavel Zubarev <pavel.zubarev@gmail.com>
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/net/mac80211/Kconfig b/net/mac80211/Kconfig
index 96ddb72760b9..8d249d705980 100644
--- a/net/mac80211/Kconfig
+++ b/net/mac80211/Kconfig
@@ -225,6 +225,17 @@ config MAC80211_VERBOSE_MHWMP_DEBUG
 
           Do not select this option.
 
+config MAC80211_VERBOSE_MESH_SYNC_DEBUG
+        bool "Verbose mesh mesh synchronization debugging"
+        depends on MAC80211_DEBUG_MENU
+        depends on MAC80211_MESH
+        ---help---
+          Selecting this option causes mac80211 to print out very verbose mesh
+          synchronization debugging messages (when mac80211 is taking part in a
+          mesh network).
+
+          Do not select this option.
+
 config MAC80211_VERBOSE_TDLS_DEBUG
         bool "Verbose TDLS debugging"
         depends on MAC80211_DEBUG_MENU