nl80211: add ability to report TX status for control port TX

This adds the necessary capabilities in nl80211 to allow drivers to
assign a cookie to control port TX frames (returned via extack in
the netlink ACK message of the command) and then later report the
frame's status.
Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
Link: https://lore.kernel.org/r/20200508144202.7678-2-markus.theil@tu-ilmenau.de
[use extack cookie instead of explicit message, recombine patches]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -4069,7 +4069,8 @@ struct cfg80211_ops {
 				   struct net_device *dev,
 				   const u8 *buf, size_t len,
 				   const u8 *dest, const __be16 proto,
-				   const bool noencrypt);
+				   const bool noencrypt,
+				   u64 *cookie);
 
 	int	(*get_ftm_responder_stats)(struct wiphy *wiphy,
 				struct net_device *dev,
@@ -7049,6 +7050,23 @@ static inline bool cfg80211_rx_mgmt(struct wireless_dev *wdev, int freq,
 void cfg80211_mgmt_tx_status(struct wireless_dev *wdev, u64 cookie,
 			     const u8 *buf, size_t len, bool ack, gfp_t gfp);
 
+/**
+ * cfg80211_control_port_tx_status - notification of TX status for control
+ *                                   port frames
+ * @wdev: wireless device receiving the frame
+ * @cookie: Cookie returned by cfg80211_ops::tx_control_port()
+ * @buf: Data frame (header + body)
+ * @len: length of the frame data
+ * @ack: Whether frame was acknowledged
+ * @gfp: context flags
+ *
+ * This function is called whenever a control port frame was requested to be
+ * transmitted with cfg80211_ops::tx_control_port() to report the TX status of
+ * the transmission attempt.
+ */
+void cfg80211_control_port_tx_status(struct wireless_dev *wdev, u64 cookie,
+				     const u8 *buf, size_t len, bool ack,
+				     gfp_t gfp);
 
 /**
  * cfg80211_rx_control_port - notification about a received control port frame

include/uapi/linux/nl80211.h

@@ -1164,6 +1164,12 @@
  *	dropped because it did not include a valid MME MIC while beacon
  *	protection was enabled (BIGTK configured in station mode).
  *
+ * @NL80211_CMD_CONTROL_PORT_FRAME_TX_STATUS: Report TX status of a control
+ *	port frame transmitted with %NL80211_CMD_CONTROL_PORT_FRAME.
+ *	%NL80211_ATTR_COOKIE identifies the TX command and %NL80211_ATTR_FRAME
+ *	includes the contents of the frame. %NL80211_ATTR_ACK flag is included
+ *	if the recipient acknowledged the frame.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -1392,6 +1398,8 @@ enum nl80211_commands {
 
 	NL80211_CMD_UNPROT_BEACON,
 
+	NL80211_CMD_CONTROL_PORT_FRAME_TX_STATUS,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
@@ -5729,6 +5737,9 @@ enum nl80211_feature_flags {
  *	report %NL80211_ATTR_SCAN_FREQ_KHZ, %NL80211_SCAN_FLAG_FREQ_KHZ must be
  *	included in the scan request.
  *
+ * @NL80211_EXT_FEATURE_CONTROL_PORT_OVER_NL80211_TX_STATUS: The driver
+ *	can report tx status for control port over nl80211 tx operations.
+ *
  * @NUM_NL80211_EXT_FEATURES: number of extended features.
  * @MAX_NL80211_EXT_FEATURES: highest extended feature index.
  */
@@ -5783,6 +5794,7 @@ enum nl80211_ext_feature_index {
 	NL80211_EXT_FEATURE_MULTICAST_REGISTRATIONS,
 	NL80211_EXT_FEATURE_BEACON_PROTECTION_CLIENT,
 	NL80211_EXT_FEATURE_SCAN_FREQ_KHZ,
+	NL80211_EXT_FEATURE_CONTROL_PORT_OVER_NL80211_TX_STATUS,
 
 	/* add new features before the definition below */
 	NUM_NL80211_EXT_FEATURES,

net/mac80211/ieee80211_i.h

@@ -1800,7 +1800,8 @@ void ieee80211_check_fast_xmit_iface(struct ieee80211_sub_if_data *sdata);
 void ieee80211_clear_fast_xmit(struct sta_info *sta);
 int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
 			      const u8 *buf, size_t len,
-			      const u8 *dest, __be16 proto, bool unencrypted);
+			      const u8 *dest, __be16 proto, bool unencrypted,
+			      u64 *cookie);
 int ieee80211_probe_mesh_link(struct wiphy *wiphy, struct net_device *dev,
 			      const u8 *buf, size_t len);
 

net/mac80211/tx.c

@@ -5339,7 +5339,8 @@ void __ieee80211_tx_skb_tid_band(struct ieee80211_sub_if_data *sdata,
 
 int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
 			      const u8 *buf, size_t len,
-			      const u8 *dest, __be16 proto, bool unencrypted)
+			      const u8 *dest, __be16 proto, bool unencrypted,
+			      u64 *cookie)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	struct ieee80211_local *local = sdata->local;

net/wireless/nl80211.c

@@ -13866,6 +13866,7 @@ static int nl80211_external_auth(struct sk_buff *skb, struct genl_info *info)
 
 static int nl80211_tx_control_port(struct sk_buff *skb, struct genl_info *info)
 {
+	bool dont_wait_for_ack = info->attrs[NL80211_ATTR_DONT_WAIT_FOR_ACK];
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
 	struct net_device *dev = info->user_ptr[1];
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
@@ -13874,6 +13875,7 @@ static int nl80211_tx_control_port(struct sk_buff *skb, struct genl_info *info)
 	u8 *dest;
 	u16 proto;
 	bool noencrypt;
+	u64 cookie = 0;
 	int err;
 
 	if (!wiphy_ext_feature_isset(&rdev->wiphy,
@@ -13918,9 +13920,12 @@ static int nl80211_tx_control_port(struct sk_buff *skb, struct genl_info *info)
 	noencrypt =
 		nla_get_flag(info->attrs[NL80211_ATTR_CONTROL_PORT_NO_ENCRYPT]);
 
-	return rdev_tx_control_port(rdev, dev, buf, len,
-				    dest, cpu_to_be16(proto), noencrypt);
-
+	err = rdev_tx_control_port(rdev, dev, buf, len,
+				   dest, cpu_to_be16(proto), noencrypt,
+				   dont_wait_for_ack ? NULL : &cookie);
+	if (!err && !dont_wait_for_ack)
+		nl_set_extack_cookie_u64(info->extack, cookie);
+	return err;
  out:
 	wdev_unlock(wdev);
 	return err;
@@ -16294,8 +16299,9 @@ int nl80211_send_mgmt(struct cfg80211_registered_device *rdev,
 	return -ENOBUFS;
 }
 
-void cfg80211_mgmt_tx_status(struct wireless_dev *wdev, u64 cookie,
-			     const u8 *buf, size_t len, bool ack, gfp_t gfp)
+static void nl80211_frame_tx_status(struct wireless_dev *wdev, u64 cookie,
+				    const u8 *buf, size_t len, bool ack,
+				    gfp_t gfp, enum nl80211_commands command)
 {
 	struct wiphy *wiphy = wdev->wiphy;
 	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
@@ -16303,13 +16309,16 @@ void cfg80211_mgmt_tx_status(struct wireless_dev *wdev, u64 cookie,
 	struct sk_buff *msg;
 	void *hdr;
 
+	if (command == NL80211_CMD_FRAME_TX_STATUS)
 		trace_cfg80211_mgmt_tx_status(wdev, cookie, ack);
+	else
+		trace_cfg80211_control_port_tx_status(wdev, cookie, ack);
 
 	msg = nlmsg_new(100 + len, gfp);
 	if (!msg)
 		return;
 
-	hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_FRAME_TX_STATUS);
+	hdr = nl80211hdr_put(msg, 0, 0, 0, command);
 	if (!hdr) {
 		nlmsg_free(msg);
 		return;
@@ -16332,9 +16341,25 @@ void cfg80211_mgmt_tx_status(struct wireless_dev *wdev, u64 cookie,
 				NL80211_MCGRP_MLME, gfp);
 	return;
 
- nla_put_failure:
+nla_put_failure:
 	nlmsg_free(msg);
 }
+
+void cfg80211_control_port_tx_status(struct wireless_dev *wdev, u64 cookie,
+				     const u8 *buf, size_t len, bool ack,
+				     gfp_t gfp)
+{
+	nl80211_frame_tx_status(wdev, cookie, buf, len, ack, gfp,
+				NL80211_CMD_CONTROL_PORT_FRAME_TX_STATUS);
+}
+EXPORT_SYMBOL(cfg80211_control_port_tx_status);
+
+void cfg80211_mgmt_tx_status(struct wireless_dev *wdev, u64 cookie,
+			     const u8 *buf, size_t len, bool ack, gfp_t gfp)
+{
+	nl80211_frame_tx_status(wdev, cookie, buf, len, ack, gfp,
+				NL80211_CMD_FRAME_TX_STATUS);
+}
 EXPORT_SYMBOL(cfg80211_mgmt_tx_status);
 
 static int __nl80211_rx_control_port(struct net_device *dev,

net/wireless/rdev-ops.h

@@ -748,13 +748,16 @@ static inline int rdev_tx_control_port(struct cfg80211_registered_device *rdev,
 				       struct net_device *dev,
 				       const void *buf, size_t len,
 				       const u8 *dest, __be16 proto,
-				       const bool noencrypt)
+				       const bool noencrypt, u64 *cookie)
 {
 	int ret;
 	trace_rdev_tx_control_port(&rdev->wiphy, dev, buf, len,
 				   dest, proto, noencrypt);
 	ret = rdev->ops->tx_control_port(&rdev->wiphy, dev, buf, len,
-					 dest, proto, noencrypt);
+					 dest, proto, noencrypt, cookie);
+	if (cookie)
+		trace_rdev_return_int_cookie(&rdev->wiphy, ret, *cookie);
+	else
 		trace_rdev_return_int(&rdev->wiphy, ret);
 	return ret;
 }

net/wireless/trace.h

@@ -2861,6 +2861,23 @@ TRACE_EVENT(cfg80211_mgmt_tx_status,
 		  WDEV_PR_ARG, __entry->cookie, BOOL_TO_STR(__entry->ack))
 );
 
+TRACE_EVENT(cfg80211_control_port_tx_status,
+	TP_PROTO(struct wireless_dev *wdev, u64 cookie, bool ack),
+	TP_ARGS(wdev, cookie, ack),
+	TP_STRUCT__entry(
+		WDEV_ENTRY
+		__field(u64, cookie)
+		__field(bool, ack)
+	),
+	TP_fast_assign(
+		WDEV_ASSIGN;
+		__entry->cookie = cookie;
+		__entry->ack = ack;
+	),
+	TP_printk(WDEV_PR_FMT", cookie: %llu, ack: %s",
+		  WDEV_PR_ARG, __entry->cookie, BOOL_TO_STR(__entry->ack))
+);
+
 TRACE_EVENT(cfg80211_rx_control_port,
 	TP_PROTO(struct net_device *netdev, struct sk_buff *skb,
 		 bool unencrypted),