mac80211: implement STA CSA for drivers using channel contexts

Limit the current implementation to a single channel context used by
a single vif, thereby avoiding multi-vif/channel complexities.

Reuse the main function from AP CSA code, but move a portion out in
order to fit the STA scenario.

Add a new mac80211 HW flag so we don't break devices that don't support
channel switch with channel-contexts. The new behavior will be opt-in.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

4 files changed, 54 insertions, 19 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index da8011920b65..f386c480e134 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1502,6 +1502,11 @@ struct ieee80211_tx_control {
  *
  * @IEEE80211_HW_TIMING_BEACON_ONLY: Use sync timing from beacon frames
  *      only, to allow getting TBTT of a DTIM beacon.
+ *
+ * @IEEE80211_HW_CHANCTX_STA_CSA: Support 802.11h based channel-switch (CSA)
+ *      for a single active channel while using channel contexts. When support
+ *      is not enabled the default action is to disconnect when getting the
+ *      CSA frame.
  */
 enum ieee80211_hw_flags {
         IEEE80211_HW_HAS_RATE_CONTROL                   = 1<<0,
@@ -1532,6 +1537,7 @@ enum ieee80211_hw_flags {
         IEEE80211_HW_P2P_DEV_ADDR_FOR_INTF              = 1<<25,
         IEEE80211_HW_TIMING_BEACON_ONLY                 = 1<<26,
         IEEE80211_HW_SUPPORTS_HT_CCK_RATES              = 1<<27,
+        IEEE80211_HW_CHANCTX_STA_CSA                    = 1<<28,
 };
 
 /**
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index b455e7264f4f..ac28af74a414 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2871,6 +2871,11 @@ void ieee80211_csa_finalize_work(struct work_struct *work)
         if (WARN_ON(err < 0))
                 return;
 
+        if (!local->use_chanctx) {
+                local->_oper_chandef = local->csa_chandef;
+                ieee80211_hw_config(local, 0);
+        }
+
         ieee80211_bss_info_change_notify(sdata, changed);
 
         switch (sdata->vif.type) {
diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 3a4764b2869e..03ba6b5c5373 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -453,11 +453,6 @@ int ieee80211_vif_change_channel(struct ieee80211_sub_if_data *sdata,
         chanctx_changed |= IEEE80211_CHANCTX_CHANGE_CHANNEL;
         drv_change_chanctx(local, ctx, chanctx_changed);
 
-        if (!local->use_chanctx) {
-                local->_oper_chandef = *chandef;
-                ieee80211_hw_config(local, 0);
-        }
-
         ieee80211_recalc_chanctx_chantype(local, ctx);
         ieee80211_recalc_smps_chanctx(local, ctx);
         ieee80211_recalc_radar_chanctx(local, ctx);
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 9fce0f49cd10..91cc8281e266 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -876,6 +876,8 @@ static void ieee80211_chswitch_work(struct work_struct *work)
                 container_of(work, struct ieee80211_sub_if_data, u.mgd.chswitch_work);
         struct ieee80211_local *local = sdata->local;
         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
+        u32 changed = 0;
+        int ret;
 
         if (!ieee80211_sdata_running(sdata))
                 return;
@@ -884,24 +886,39 @@ static void ieee80211_chswitch_work(struct work_struct *work)
         if (!ifmgd->associated)
                 goto out;
 
-        local->_oper_chandef = local->csa_chandef;
+        ret = ieee80211_vif_change_channel(sdata, &local->csa_chandef,
+                                           &changed);
+        if (ret) {
+                sdata_info(sdata,
+                           "vif channel switch failed, disconnecting\n");
+                ieee80211_queue_work(&sdata->local->hw,
+                                     &ifmgd->csa_connection_drop_work);
+                goto out;
+        }
 
-        if (!local->ops->channel_switch) {
-                /* call "hw_config" only if doing sw channel switch */
-                ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
-        } else {
-                /* update the device channel directly */
-                local->hw.conf.chandef = local->_oper_chandef;
+        if (!local->use_chanctx) {
+                local->_oper_chandef = local->csa_chandef;
+                /* Call "hw_config" only if doing sw channel switch.
+                 * Otherwise update the channel directly
+                 */
+                if (!local->ops->channel_switch)
+                        ieee80211_hw_config(local, 0);
+                else
+                        local->hw.conf.chandef = local->_oper_chandef;
         }
 
         /* XXX: shouldn't really modify cfg80211-owned data! */
-        ifmgd->associated->channel = local->_oper_chandef.chan;
+        ifmgd->associated->channel = local->csa_chandef.chan;
 
         /* XXX: wait for a beacon first? */
         ieee80211_wake_queues_by_reason(&local->hw,
                                         IEEE80211_MAX_QUEUE_MAP,
                                         IEEE80211_QUEUE_STOP_REASON_CSA);
+
+        ieee80211_bss_info_change_notify(sdata, changed);
+
  out:
+        sdata->vif.csa_active = false;
         ifmgd->flags &= ~IEEE80211_STA_CSA_RECEIVED;
         sdata_unlock(sdata);
 }
@@ -983,17 +1000,28 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
         }
 
         ifmgd->flags |= IEEE80211_STA_CSA_RECEIVED;
+        sdata->vif.csa_active = true;
 
+        mutex_lock(&local->chanctx_mtx);
         if (local->use_chanctx) {
-                sdata_info(sdata,
-                           "not handling channel switch with channel contexts\n");
-                ieee80211_queue_work(&local->hw,
-                                     &ifmgd->csa_connection_drop_work);
-                return;
+                u32 num_chanctx = 0;
+                list_for_each_entry(chanctx, &local->chanctx_list, list)
+                       num_chanctx++;
+
+                if (num_chanctx > 1 ||
+                    !(local->hw.flags & IEEE80211_HW_CHANCTX_STA_CSA)) {
+                        sdata_info(sdata,
+                                   "not handling chan-switch with channel contexts\n");
+                        ieee80211_queue_work(&local->hw,
+                                             &ifmgd->csa_connection_drop_work);
+                        mutex_unlock(&local->chanctx_mtx);
+                        return;
+                }
         }
 
-        mutex_lock(&local->chanctx_mtx);
         if (WARN_ON(!rcu_access_pointer(sdata->vif.chanctx_conf))) {
+                ieee80211_queue_work(&local->hw,
+                                     &ifmgd->csa_connection_drop_work);
                 mutex_unlock(&local->chanctx_mtx);
                 return;
         }
@@ -1955,6 +1983,7 @@ static void __ieee80211_disconnect(struct ieee80211_sub_if_data *sdata)
                                WLAN_REASON_DISASSOC_DUE_TO_INACTIVITY,
                                true, frame_buf);
         ifmgd->flags &= ~IEEE80211_STA_CSA_RECEIVED;
+        sdata->vif.csa_active = false;
         ieee80211_wake_queues_by_reason(&sdata->local->hw,
                                         IEEE80211_MAX_QUEUE_MAP,
                                         IEEE80211_QUEUE_STOP_REASON_CSA);