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>
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index b1b4b14..f75f5d9 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -55,6 +55,7 @@
* @WLAN_STA_4ADDR_EVENT: 4-addr event was already sent for this frame.
* @WLAN_STA_INSERTED: This station is inserted into the hash table.
* @WLAN_STA_RATE_CONTROL: rate control was initialized for this station.
+ * @WLAN_STA_TOFFSET_KNOWN: toffset calculated for this station is valid.
*/
enum ieee80211_sta_info_flags {
WLAN_STA_AUTH,
@@ -76,6 +77,7 @@
WLAN_STA_4ADDR_EVENT,
WLAN_STA_INSERTED,
WLAN_STA_RATE_CONTROL,
+ WLAN_STA_TOFFSET_KNOWN,
};
#define STA_TID_NUM 16
@@ -268,6 +270,7 @@
* @plink_timeout: timeout of peer link
* @plink_timer: peer link watch timer
* @plink_timer_was_running: used by suspend/resume to restore timers
+ * @t_offset: timing offset relative to this host
* @debugfs: debug filesystem info
* @dead: set to true when sta is unlinked
* @uploaded: set to true when sta is uploaded to the driver
@@ -357,6 +360,8 @@
enum nl80211_plink_state plink_state;
u32 plink_timeout;
struct timer_list plink_timer;
+ s64 t_offset;
+ s64 t_offset_setpoint;
#endif
#ifdef CONFIG_MAC80211_DEBUGFS