[PATCH wireless-next v4 11/21] wifi: nl80211/cfg80211: define API to notify SMD Drain completion

[Pooventhiran G]

The non-AP MLD that has started transitioning to the target AP MLD (ST
Execution) from the current AP MLD will be in downlink draining until
the Nominal Maximum DL Draining Period Duration field advertised in the
ST Execution Response frame.

But if the AP MLD has completed draining the packets before the draining
period completion, the draining can be terminated early. Add cfg80211
and nl80211 APIs for the drivers to send this completion event to
userspace to perform the necessary clean-ups.

Suggested-by: Rohan Dutta <drohan@xxxxxxxxxxxxxxxx>
Signed-off-by: Pooventhiran G <pooventhiran.g@xxxxxxxxxxxxxxxx>
---
 include/net/cfg80211.h       | 11 +++++++++++
 include/uapi/linux/nl80211.h | 11 +++++++++++
 net/wireless/mlme.c          | 11 +++++++++++
 net/wireless/nl80211.c       | 32 ++++++++++++++++++++++++++++++++
 net/wireless/nl80211.h       |  3 +++
 5 files changed, 68 insertions(+)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 36ee10ebd62c..7ffe2b8cdd3d 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -11304,4 +11304,15 @@ void cfg80211_get_smd_ctx_done(struct wireless_dev *wdev,
 			       const u8 *sta_addr,
 			       struct cfg80211_smd_transition_info *st_info);
 
+/**
+ * cfg80211_notify_smd_drain_completion - notify userspace about downlink drain
+ *	early termination.
+ * @wdev: wireless device corresponding to the AP MLD
+ * @sta_addr: non-AP MLD address for which DL draining is being terminated
+ *
+ * Should be called under wiphy_lock.
+ */
+void cfg80211_notify_smd_drain_completion(struct wireless_dev *wdev,
+					  const u8 *sta_addr);
+
 #endif /* __NET_CFG80211_H */
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index fbc23aca006e..993bf4fe571e 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -388,6 +388,12 @@
  * AP MLD can request the context from the driver on the target's behalf using
  * %NL80211_CMD_GET_SMD_CTX and the response can be reported back using
  * %NL80211_CMD_SMD_CTX_EVENT.
+ *
+ * The current AP MLD, after successful execution of the non-AP MLD with the
+ * target AP MLD, can continue to drain the buffered packets if a non-zero
+ * Nominal Maximum DL Draining Period Duration has been sent in the ST Execution
+ * Response. Drivers, however, can terminate draining early using the
+ * %NL80211_CMD_SMD_DRAIN_COMPLETION_EVENT event.
  */
 
 /**
@@ -1529,6 +1535,10 @@
  *	(requested via %NL80211_CMD_GET_SMD_CTX) to userspace. It carries
  *	%NL80211_ATTR_MLD_ADDR, %NL80211_ATTR_SMD_CTX_TYPE, and
  *	%NL80211_ATTR_SMD_CTX.
+ * @NL80211_CMD_SMD_DRAIN_COMPLETION_EVENT: Event indicating to userspace that
+ *	the Downlink Drain for the station, identified by
+ *	%NL80211_ATTR_MLD_ADDR, has been terminated early by the driver.
+ *	Userspace can remove the station upon this event.
  *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
@@ -1815,6 +1825,7 @@ enum nl80211_commands {
 	NL80211_CMD_SET_SMD_CTX,
 	NL80211_CMD_GET_SMD_CTX,
 	NL80211_CMD_SMD_CTX_EVENT,
+	NL80211_CMD_SMD_DRAIN_COMPLETION_EVENT,
 
 	/* add new commands above here */
 
diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
index 0631e42e2fa1..2a1e00c6f56b 100644
--- a/net/wireless/mlme.c
+++ b/net/wireless/mlme.c
@@ -1607,3 +1607,14 @@ void cfg80211_get_smd_ctx_done(struct wireless_dev *wdev,
 	kfree(pending);
 }
 EXPORT_SYMBOL(cfg80211_get_smd_ctx_done);
+
+void cfg80211_notify_smd_drain_completion(struct wireless_dev *wdev,
+					  const u8 *sta_addr)
+{
+	struct wiphy *wiphy = wdev->wiphy;
+
+	lockdep_assert_wiphy(wiphy);
+
+	nl80211_notify_smd_drain_completion(wdev, sta_addr);
+}
+EXPORT_SYMBOL(cfg80211_notify_smd_drain_completion);
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index f30110d998d0..004ee5c6ef6b 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -25273,6 +25273,38 @@ nl80211_notify_get_smd_ctx_done(struct wireless_dev *wdev,
 	nlmsg_free(msg);
 }
 
+void nl80211_notify_smd_drain_completion(struct wireless_dev *wdev,
+					 const u8 *sta_addr)
+{
+	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wdev->wiphy);
+	struct net_device *dev = wdev->netdev;
+	struct sk_buff *msg;
+	void *hdr;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return;
+
+	hdr = nl80211hdr_put(msg, 0, 0, 0,
+			     NL80211_CMD_SMD_DRAIN_COMPLETION_EVENT);
+	if (!hdr)
+		goto nla_put_failure;
+
+	if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx) ||
+	    nla_put_u32(msg, NL80211_ATTR_IFINDEX, dev->ifindex) ||
+	    nla_put(msg, NL80211_ATTR_MLD_ADDR, ETH_ALEN, sta_addr))
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+
+	genlmsg_multicast_netns(&nl80211_fam, wiphy_net(&rdev->wiphy), msg, 0,
+				NL80211_MCGRP_MLME, GFP_KERNEL);
+	return;
+
+nla_put_failure:
+	nlmsg_free(msg);
+}
+
 /* initialisation/exit functions */
 
 int __init nl80211_init(void)
diff --git a/net/wireless/nl80211.h b/net/wireless/nl80211.h
index 2855d30ba354..8088785f0b2d 100644
--- a/net/wireless/nl80211.h
+++ b/net/wireless/nl80211.h
@@ -138,4 +138,7 @@ nl80211_notify_get_smd_ctx_done(struct wireless_dev *wdev,
 				const u8 *sta_addr,
 				struct cfg80211_smd_transition_info *st_info);
 
+void nl80211_notify_smd_drain_completion(struct wireless_dev *wdev,
+					 const u8 *sta_addr);
+
 #endif /* __NET_WIRELESS_NL80211_H */

-- 
2.34.1