From a802a6eba13282ddd5718f8db9d476e42e84e2ba Mon Sep 17 00:00:00 2001 From: Javier Cardona Date: Thu, 12 Apr 2012 14:32:22 -0700 Subject: [PATCH] mac80211: Choose a new toffset setpoint if a big tsf jump is detected. Signed-off-by: Javier Cardona Signed-off-by: John W. Linville --- net/mac80211/mesh_sync.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) diff --git a/net/mac80211/mesh_sync.c b/net/mac80211/mesh_sync.c index f78b0139856f..22a5f1e66996 100644 --- a/net/mac80211/mesh_sync.c +++ b/net/mac80211/mesh_sync.c @@ -22,7 +22,14 @@ /* This is not in the standard. It represents a tolerable tbtt drift below * which we do no TSF adjustment. */ -#define TBTT_MINIMUM_ADJUSTMENT 10 +#define TOFFSET_MINIMUM_ADJUSTMENT 10 + +/* This is not in the standard. It represents the maximum Toffset jump above + * which we'll invalidate the Toffset setpoint and choose a new setpoint. This + * could be, for instance, in case a neighbor is restarted and its TSF counter + * reset. + * */ +#define TOFFSET_MAXIMUM_ADJUSTMENT 30000 /* 30 ms */ struct sync_method { u8 method; @@ -156,15 +163,22 @@ static void mesh_sync_offset_rx_bcn_presp(struct ieee80211_sub_if_data *sdata, if (test_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN)) { s64 t_clockdrift = sta->t_offset_setpoint - sta->t_offset; - - msync_dbg("STA %pM : sta->t_offset=%lld," - " sta->t_offset_setpoint=%lld," - " t_clockdrift=%lld", + msync_dbg("STA %pM : sta->t_offset=%lld, sta->t_offset_setpoint=%lld, t_clockdrift=%lld", sta->sta.addr, (long long) sta->t_offset, (long long) sta->t_offset_setpoint, (long long) t_clockdrift); + + if (t_clockdrift > TOFFSET_MAXIMUM_ADJUSTMENT || + t_clockdrift < -TOFFSET_MAXIMUM_ADJUSTMENT) { + msync_dbg("STA %pM : t_clockdrift=%lld too large, setpoint reset", + sta->sta.addr, + (long long) t_clockdrift); + clear_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN); + goto no_sync; + } + rcu_read_unlock(); spin_lock_bh(&ifmsh->sync_offset_lock); @@ -200,7 +214,7 @@ static void mesh_sync_offset_adjust_tbtt(struct ieee80211_sub_if_data *sdata) spin_lock_bh(&ifmsh->sync_offset_lock); if (ifmsh->sync_offset_clockdrift_max > - TBTT_MINIMUM_ADJUSTMENT) { + TOFFSET_MINIMUM_ADJUSTMENT) { /* Since ajusting the tsf here would * require a possibly blocking call * to the driver tsf setter, we punt -- 2.30.2