mac80211: rework tx encapsulation offload API

The current API (which lets the driver turn on/off per vif directly) has a
number of limitations:
- it does not deal with AP_VLAN
- conditions for enabling (no tkip, no monitor) are only checked at
  add_interface time
- no way to indicate 4-addr support

In order to address this, store offload flags in struct ieee80211_vif
(easy to extend for decap offload later). mac80211 initially sets the enable
flag, but gives the driver a chance to modify it before its settings are
applied. In addition to the .add_interface op, a .update_vif_offload op is
introduced, which can be used for runtime changes.

If a driver can't disable encap offload at runtime, or if it has some extra
limitations, it can simply override the flags within those ops.

Support for encap offload with 4-address mode interfaces can be enabled
by setting a flag from .add_interface or .update_vif_offload.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20200908123702.88454-6-nbd@nbd.name
[resolved conflict with commit aa2092a ("ath11k: add raw mode and
software crypto support")]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/ath/ath11k/mac.c

@@ -4349,6 +4349,37 @@ static int ath11k_set_he_mu_sounding_mode(struct ath11k *ar,
 	return ret;
 }
 
+static void ath11k_mac_op_update_vif_offload(struct ieee80211_hw *hw,
+					    struct ieee80211_vif *vif)
+{
+	struct ath11k *ar = hw->priv;
+	struct ath11k_base *ab = ar->ab;
+	struct ath11k_vif *arvif = ath11k_vif_to_arvif(vif);
+	u32 param_id, param_value;
+	int ret;
+
+	param_id = WMI_VDEV_PARAM_TX_ENCAP_TYPE;
+	if (ath11k_frame_mode != ATH11K_HW_TXRX_ETHERNET ||
+	    (vif->type != NL80211_IFTYPE_STATION &&
+	     vif->type != NL80211_IFTYPE_AP))
+		vif->offload_flags &= ~IEEE80211_OFFLOAD_ENCAP_ENABLED;
+
+	if (vif->offload_flags & IEEE80211_OFFLOAD_ENCAP_ENABLED)
+		param_value = ATH11K_HW_TXRX_ETHERNET;
+	else if (test_bit(ATH11K_FLAG_RAW_MODE, &ab->dev_flags))
+		param_value = ATH11K_HW_TXRX_RAW;
+	else
+		param_value = ATH11K_HW_TXRX_NATIVE_WIFI;
+
+	ret = ath11k_wmi_vdev_set_param_cmd(ar, arvif->vdev_id,
+					    param_id, param_value);
+	if (ret) {
+		ath11k_warn(ab, "failed to set vdev %d tx encap mode: %d\n",
+			    arvif->vdev_id, ret);
+		vif->offload_flags &= ~IEEE80211_OFFLOAD_ENCAP_ENABLED;
+	}
+}
+
 static int ath11k_mac_op_add_interface(struct ieee80211_hw *hw,
 				       struct ieee80211_vif *vif)
 {
@@ -4358,7 +4389,6 @@ static int ath11k_mac_op_add_interface(struct ieee80211_hw *hw,
 	struct vdev_create_params vdev_param = {0};
 	struct peer_create_params peer_param;
 	u32 param_id, param_value;
-	int hw_encap = 0;
 	u16 nss;
 	int i;
 	int ret;
@@ -4452,32 +4482,7 @@ static int ath11k_mac_op_add_interface(struct ieee80211_hw *hw,
 	list_add(&arvif->list, &ar->arvifs);
 	spin_unlock_bh(&ar->data_lock);
 
-	param_id = WMI_VDEV_PARAM_TX_ENCAP_TYPE;
-	if (ath11k_frame_mode == ATH11K_HW_TXRX_ETHERNET)
-		switch (vif->type) {
-		case NL80211_IFTYPE_STATION:
-		case NL80211_IFTYPE_AP_VLAN:
-		case NL80211_IFTYPE_AP:
-			hw_encap = 1;
-			break;
-		default:
-			break;
-		}
-
-	if (ieee80211_set_hw_80211_encap(vif, hw_encap))
-		param_value = ATH11K_HW_TXRX_ETHERNET;
-	else if (test_bit(ATH11K_FLAG_RAW_MODE, &ab->dev_flags))
-		param_value = ATH11K_HW_TXRX_RAW;
-	else
-		param_value = ATH11K_HW_TXRX_NATIVE_WIFI;
-
-	ret = ath11k_wmi_vdev_set_param_cmd(ar, arvif->vdev_id,
-					    param_id, param_value);
-	if (ret) {
-		ath11k_warn(ab, "failed to set vdev %d tx encap mode: %d\n",
-			    arvif->vdev_id, ret);
-		goto err_vdev_del;
-	}
+	ath11k_mac_op_update_vif_offload(hw, vif);
 
 	nss = get_num_chains(ar->cfg_tx_chainmask) ? : 1;
 	ret = ath11k_wmi_vdev_set_param_cmd(ar, arvif->vdev_id,
@@ -5840,6 +5845,7 @@ static const struct ieee80211_ops ath11k_ops = {
 	.reconfig_complete              = ath11k_mac_op_reconfig_complete,
 	.add_interface                  = ath11k_mac_op_add_interface,
 	.remove_interface		= ath11k_mac_op_remove_interface,
+	.update_vif_offload		= ath11k_mac_op_update_vif_offload,
 	.config                         = ath11k_mac_op_config,
 	.bss_info_changed               = ath11k_mac_op_bss_info_changed,
 	.configure_filter		= ath11k_mac_op_configure_filter,
@@ -6148,6 +6154,7 @@ static int __ath11k_mac_register(struct ath11k *ar)
 	ieee80211_hw_set(ar->hw, QUEUE_CONTROL);
 	ieee80211_hw_set(ar->hw, SUPPORTS_TX_FRAG);
 	ieee80211_hw_set(ar->hw, REPORTS_LOW_ACK);
+	ieee80211_hw_set(ar->hw, SUPPORTS_TX_ENCAP_OFFLOAD);
 	if (ht_cap & WMI_HT_CAP_ENABLED) {
 		ieee80211_hw_set(ar->hw, AMPDU_AGGREGATION);
 		ieee80211_hw_set(ar->hw, TX_AMPDU_SETUP_IN_HW);

include/net/mac80211.h

@@ -1606,6 +1606,21 @@ enum ieee80211_vif_flags {
 	IEEE80211_VIF_GET_NOA_UPDATE		= BIT(3),
 };
 
+
+/**
+ * enum ieee80211_offload_flags - virtual interface offload flags
+ *
+ * @IEEE80211_OFFLOAD_ENCAP_ENABLED: tx encapsulation offload is enabled
+ *	The driver supports sending frames passed as 802.3 frames by mac80211.
+ *	It must also support sending 802.11 packets for the same interface.
+ * @IEEE80211_OFFLOAD_ENCAP_4ADDR: support 4-address mode encapsulation offload
+ */
+
+enum ieee80211_offload_flags {
+	IEEE80211_OFFLOAD_ENCAP_ENABLED		= BIT(0),
+	IEEE80211_OFFLOAD_ENCAP_4ADDR		= BIT(1),
+};
+
 /**
  * struct ieee80211_vif - per-interface data
  *
@@ -1626,6 +1641,11 @@ enum ieee80211_vif_flags {
  *	these need to be set (or cleared) when the interface is added
  *	or, if supported by the driver, the interface type is changed
  *	at runtime, mac80211 will never touch this field
+ * @offloaad_flags: hardware offload capabilities/flags for this interface.
+ *	These are initialized by mac80211 before calling .add_interface,
+ *	.change_interface or .update_vif_offload and updated by the driver
+ *	within these ops, based on supported features or runtime change
+ *	restrictions.
  * @hw_queue: hardware queue for each AC
  * @cab_queue: content-after-beacon (DTIM beacon really) queue, AP mode only
  * @chanctx_conf: The channel context this interface is assigned to, or %NULL
@@ -1662,6 +1682,7 @@ struct ieee80211_vif {
 	struct ieee80211_chanctx_conf __rcu *chanctx_conf;
 
 	u32 driver_flags;
+	u32 offload_flags;
 
 #ifdef CONFIG_MAC80211_DEBUGFS
 	struct dentry *debugfs_dir;
@@ -2328,6 +2349,9 @@ struct ieee80211_txq {
  *	aggregating MPDUs with the same keyid, allowing mac80211 to keep Tx
  *	A-MPDU sessions active while rekeying with Extended Key ID.
  *
+ * @IEEE80211_HW_SUPPORTS_TX_ENCAP_OFFLOAD: Hardware supports tx encapsulation
+ *	offload
+ *
  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
  */
 enum ieee80211_hw_flags {
@@ -2380,6 +2404,7 @@ enum ieee80211_hw_flags {
 	IEEE80211_HW_SUPPORTS_MULTI_BSSID,
 	IEEE80211_HW_SUPPORTS_ONLY_HE_MULTI_BSSID,
 	IEEE80211_HW_AMPDU_KEYBORDER_SUPPORT,
+	IEEE80211_HW_SUPPORTS_TX_ENCAP_OFFLOAD,
 
 	/* keep last, obviously */
 	NUM_IEEE80211_HW_FLAGS
@@ -3814,6 +3839,8 @@ enum ieee80211_reconfig_type {
  * @set_tid_config: Apply TID specific configurations. This callback may sleep.
  * @reset_tid_config: Reset TID specific configuration for the peer.
  *	This callback may sleep.
+ * @update_vif_config: Update virtual interface offload flags
+ *	This callback may sleep.
  */
 struct ieee80211_ops {
 	void (*tx)(struct ieee80211_hw *hw,
@@ -4125,6 +4152,8 @@ struct ieee80211_ops {
 	int (*reset_tid_config)(struct ieee80211_hw *hw,
 				struct ieee80211_vif *vif,
 				struct ieee80211_sta *sta, u8 tids);
+	void (*update_vif_offload)(struct ieee80211_hw *hw,
+				   struct ieee80211_vif *vif);
 };
 
 /**

net/mac80211/debugfs.c

@@ -408,6 +408,7 @@ static const char *hw_flag_names[] = {
 	FLAG(SUPPORTS_MULTI_BSSID),
 	FLAG(SUPPORTS_ONLY_HE_MULTI_BSSID),
 	FLAG(AMPDU_KEYBORDER_SUPPORT),
+	FLAG(SUPPORTS_TX_ENCAP_OFFLOAD),
 #undef FLAG
 };
 

net/mac80211/driver-ops.h

@@ -1384,4 +1384,19 @@ static inline int drv_reset_tid_config(struct ieee80211_local *local,
 
 	return ret;
 }
+
+static inline void drv_update_vif_offload(struct ieee80211_local *local,
+					  struct ieee80211_sub_if_data *sdata)
+{
+	might_sleep();
+	check_sdata_in_driver(sdata);
+
+	if (!local->ops->update_vif_offload)
+		return;
+
+	trace_drv_update_vif_offload(local, sdata);
+	local->ops->update_vif_offload(&local->hw, &sdata->vif);
+	trace_drv_return_void(local);
+}
+
 #endif /* __MAC80211_DRIVER_OPS */

net/mac80211/ieee80211_i.h

@@ -989,8 +989,6 @@ struct ieee80211_sub_if_data {
 	} debugfs;
 #endif
 
-	bool hw_80211_encap;
-
 	/* must be last, dynamically sized area in this! */
 	struct ieee80211_vif vif;
 };
@@ -1767,6 +1765,7 @@ void ieee80211_del_virtual_monitor(struct ieee80211_local *local);
 bool __ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata);
 void ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata,
 			      bool update_bss);
+void ieee80211_recalc_offload(struct ieee80211_local *local);
 
 static inline bool ieee80211_sdata_running(struct ieee80211_sub_if_data *sdata)
 {