mac80211: introduce individual TWT support in AP mode

Introduce TWT action frames parsing support to mac80211.
Currently just individual TWT agreement are support in AP mode.
Whenever the AP receives a TWT action frame from an associated client,
after performing sanity checks, it will notify the underlay driver with
requested parameters in order to check if they are supported and if there
is enough room for a new agreement. The driver is expected to set the
agreement result and report it to mac80211.

Drivers supporting this have two new callbacks:
 - add_twt_setup (mandatory)
 - twt_teardown_request (optional)

mac80211 will send an action frame reply according to the result
reported by the driver.

Tested-by: Peter Chiu <chui-hao.chiu@mediatek.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/257512f2e22ba42b9f2624942a128dd8f141de4b.1629741512.git.lorenzo@kernel.org
[use le16p_replace_bits(), minor cleanups, use (void *) casts,
 fix to use ieee80211_get_he_iftype_cap() correctly]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -3926,6 +3926,13 @@ struct ieee80211_prep_tx_info {
  * @set_sar_specs: Update the SAR (TX power) settings.
  * @sta_set_decap_offload: Called to notify the driver when a station is allowed
  *	to use rx decapsulation offload
+ * @add_twt_setup: Update hw with TWT agreement parameters received from the peer.
+ *	This callback allows the hw to check if requested parameters
+ *	are supported and if there is enough room for a new agreement.
+ *	The hw is expected to set agreement result in the req_type field of
+ *	twt structure.
+ * @twt_teardown_request: Update the hw with TWT teardown request received
+ *	from the peer.
  */
 struct ieee80211_ops {
 	void (*tx)(struct ieee80211_hw *hw,
@@ -4249,6 +4256,11 @@ struct ieee80211_ops {
 	void (*sta_set_decap_offload)(struct ieee80211_hw *hw,
 				      struct ieee80211_vif *vif,
 				      struct ieee80211_sta *sta, bool enabled);
+	void (*add_twt_setup)(struct ieee80211_hw *hw,
+			      struct ieee80211_sta *sta,
+			      struct ieee80211_twt_setup *twt);
+	void (*twt_teardown_request)(struct ieee80211_hw *hw,
+				     struct ieee80211_sta *sta, u8 flowid);
 };
 
 /**

net/mac80211/driver-ops.h

@@ -1447,4 +1447,40 @@ static inline void drv_sta_set_decap_offload(struct ieee80211_local *local,
 	trace_drv_return_void(local);
 }
 
+static inline void drv_add_twt_setup(struct ieee80211_local *local,
+				     struct ieee80211_sub_if_data *sdata,
+				     struct ieee80211_sta *sta,
+				     struct ieee80211_twt_setup *twt)
+{
+	struct ieee80211_twt_params *twt_agrt;
+
+	might_sleep();
+
+	if (!check_sdata_in_driver(sdata))
+		return;
+
+	twt_agrt = (void *)twt->params;
+
+	trace_drv_add_twt_setup(local, sta, twt, twt_agrt);
+	local->ops->add_twt_setup(&local->hw, sta, twt);
+	trace_drv_return_void(local);
+}
+
+static inline void drv_twt_teardown_request(struct ieee80211_local *local,
+					    struct ieee80211_sub_if_data *sdata,
+					    struct ieee80211_sta *sta,
+					    u8 flowid)
+{
+	might_sleep();
+	if (!check_sdata_in_driver(sdata))
+		return;
+
+	if (!local->ops->twt_teardown_request)
+		return;
+
+	trace_drv_twt_teardown_request(local, sta, flowid);
+	local->ops->twt_teardown_request(&local->hw, sta, flowid);
+	trace_drv_return_void(local);
+}
+
 #endif /* __MAC80211_DRIVER_OPS */

net/mac80211/ieee80211_i.h

@@ -946,6 +946,7 @@ struct ieee80211_sub_if_data {
 
 	struct work_struct work;
 	struct sk_buff_head skb_queue;
+	struct sk_buff_head status_queue;
 
 	u8 needed_rx_chains;
 	enum ieee80211_smps_mode smps_mode;
@@ -2080,6 +2081,11 @@ ieee80211_he_op_ie_to_bss_conf(struct ieee80211_vif *vif,
 
 /* S1G */
 void ieee80211_s1g_sta_rate_init(struct sta_info *sta);
+bool ieee80211_s1g_is_twt_setup(struct sk_buff *skb);
+void ieee80211_s1g_rx_twt_action(struct ieee80211_sub_if_data *sdata,
+				 struct sk_buff *skb);
+void ieee80211_s1g_status_twt_action(struct ieee80211_sub_if_data *sdata,
+				     struct sk_buff *skb);
 
 /* Spectrum management */
 void ieee80211_process_measurement_req(struct ieee80211_sub_if_data *sdata,

net/mac80211/iface.c

@@ -552,6 +552,7 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata, bool going_do
 		 */
 		ieee80211_free_keys(sdata, true);
 		skb_queue_purge(&sdata->skb_queue);
+		skb_queue_purge(&sdata->status_queue);
 	}
 
 	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
@@ -984,6 +985,7 @@ int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
 	}
 
 	skb_queue_head_init(&sdata->skb_queue);
+	skb_queue_head_init(&sdata->status_queue);
 	INIT_WORK(&sdata->work, ieee80211_iface_work);
 
 	return 0;
@@ -1382,6 +1384,16 @@ static void ieee80211_iface_process_skb(struct ieee80211_local *local,
 			WARN_ON(1);
 			break;
 		}
+	} else if (ieee80211_is_action(mgmt->frame_control) &&
+		   mgmt->u.action.category == WLAN_CATEGORY_S1G) {
+		switch (mgmt->u.action.u.s1g.action_code) {
+		case WLAN_S1G_TWT_TEARDOWN:
+		case WLAN_S1G_TWT_SETUP:
+			ieee80211_s1g_rx_twt_action(sdata, skb);
+			break;
+		default:
+			break;
+		}
 	} else if (ieee80211_is_ext(mgmt->frame_control)) {
 		if (sdata->vif.type == NL80211_IFTYPE_STATION)
 			ieee80211_sta_rx_queued_ext(sdata, skb);
@@ -1437,6 +1449,24 @@ static void ieee80211_iface_process_skb(struct ieee80211_local *local,
 	}
 }
 
+static void ieee80211_iface_process_status(struct ieee80211_sub_if_data *sdata,
+					   struct sk_buff *skb)
+{
+	struct ieee80211_mgmt *mgmt = (void *)skb->data;
+
+	if (ieee80211_is_action(mgmt->frame_control) &&
+	    mgmt->u.action.category == WLAN_CATEGORY_S1G) {
+		switch (mgmt->u.action.u.s1g.action_code) {
+		case WLAN_S1G_TWT_TEARDOWN:
+		case WLAN_S1G_TWT_SETUP:
+			ieee80211_s1g_status_twt_action(sdata, skb);
+			break;
+		default:
+			break;
+		}
+	}
+}
+
 static void ieee80211_iface_work(struct work_struct *work)
 {
 	struct ieee80211_sub_if_data *sdata =
@@ -1466,6 +1496,16 @@ static void ieee80211_iface_work(struct work_struct *work)
 		kcov_remote_stop();
 	}
 
+	/* process status queue */
+	while ((skb = skb_dequeue(&sdata->status_queue))) {
+		kcov_remote_start_common(skb_get_kcov_handle(skb));
+
+		ieee80211_iface_process_status(sdata, skb);
+		kfree_skb(skb);
+
+		kcov_remote_stop();
+	}
+
 	/* then other type-dependent work */
 	switch (sdata->vif.type) {
 	case NL80211_IFTYPE_STATION:
@@ -1529,6 +1569,7 @@ static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata,
 	}
 
 	skb_queue_head_init(&sdata->skb_queue);
+	skb_queue_head_init(&sdata->status_queue);
 	INIT_WORK(&sdata->work, ieee80211_iface_work);
 	INIT_WORK(&sdata->recalc_smps, ieee80211_recalc_smps_work);
 	INIT_WORK(&sdata->csa_finalize_work, ieee80211_csa_finalize_work);

net/mac80211/rx.c

@@ -3212,6 +3212,68 @@ ieee80211_rx_h_mgmt_check(struct ieee80211_rx_data *rx)
 	return RX_CONTINUE;
 }
 
+static bool
+ieee80211_process_rx_twt_action(struct ieee80211_rx_data *rx)
+{
+	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *)rx->skb->data;
+	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
+	struct ieee80211_sub_if_data *sdata = rx->sdata;
+	const struct ieee80211_sta_he_cap *hecap;
+	struct ieee80211_supported_band *sband;
+
+	/* TWT actions are only supported in AP for the moment */
+	if (sdata->vif.type != NL80211_IFTYPE_AP)
+		return false;
+
+	if (!rx->local->ops->add_twt_setup)
+		return false;
+
+	sband = rx->local->hw.wiphy->bands[status->band];
+	hecap = ieee80211_get_he_iftype_cap(sband,
+					    ieee80211_vif_type_p2p(&sdata->vif));
+	if (!hecap)
+		return false;
+
+	if (!(hecap->he_cap_elem.mac_cap_info[0] &
+	      IEEE80211_HE_MAC_CAP0_TWT_RES))
+		return false;
+
+	if (!rx->sta)
+		return false;
+
+	switch (mgmt->u.action.u.s1g.action_code) {
+	case WLAN_S1G_TWT_SETUP: {
+		struct ieee80211_twt_setup *twt;
+
+		if (rx->skb->len < IEEE80211_MIN_ACTION_SIZE +
+				   1 + /* action code */
+				   sizeof(struct ieee80211_twt_setup) +
+				   2 /* TWT req_type agrt */)
+			break;
+
+		twt = (void *)mgmt->u.action.u.s1g.variable;
+		if (twt->element_id != WLAN_EID_S1G_TWT)
+			break;
+
+		if (rx->skb->len < IEEE80211_MIN_ACTION_SIZE +
+				   4 + /* action code + token + tlv */
+				   twt->length)
+			break;
+
+		return true; /* queue the frame */
+	}
+	case WLAN_S1G_TWT_TEARDOWN:
+		if (rx->skb->len < IEEE80211_MIN_ACTION_SIZE + 2)
+			break;
+
+		return true; /* queue the frame */
+	default:
+		break;
+	}
+
+	return false;
+}
+
 static ieee80211_rx_result debug_noinline
 ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 {
@@ -3491,6 +3553,17 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 		    !mesh_path_sel_is_hwmp(sdata))
 			break;
 		goto queue;
+	case WLAN_CATEGORY_S1G:
+		switch (mgmt->u.action.u.s1g.action_code) {
+		case WLAN_S1G_TWT_SETUP:
+		case WLAN_S1G_TWT_TEARDOWN:
+			if (ieee80211_process_rx_twt_action(rx))
+				goto queue;
+			break;
+		default:
+			break;
+		}
+		break;
 	}
 
 	return RX_CONTINUE;