wifi: nl80211: Add a notification to notify NAN channel evacuation

If all available channel resources are used for NAN channels, and one of
them is shared with another interface, and that interface needs to move
to a different channel (for example STA interface that needs to do a
channel or a link switch), then the driver can evacuate one of the NAN
channels (i.e. detach it from its channel resource and announce to the
peers that this channel is ULWed). In that case, the driver needs to
notify user space about the channel evacuation, so the user space can
adjust the local schedule accordingly.

Add a notification to let userspace know about it.

Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20260219114327.d5bebfd5ff73.Iaaf5ef17e1ab7a38c19d60558e68fcf517e2b400@changeid
Link: https://patch.msgid.link/20260318123926.206536-11-miriam.rachel.korenblit@intel.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 21 insertions, 6 deletions

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 947ec7079484..3d55bf4be36f 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1406,6 +1406,15 @@
  *	with the updated ULW blob of the device. User space can use this blob
  *	to attach to frames sent to peers. This notification contains
  *	%NL80211_ATTR_NAN_ULW with the ULW blob.
+ * @NL80211_CMD_NAN_CHANNEL_EVAC: Notification to indicate that a NAN
+ *	channel has been evacuated due to resource conflicts with other
+ *	interfaces. This can happen when another interface sharing the channel
+ *	resource with NAN needs to move to a different channel (e.g., channel
+ *	switch or link switch on a BSS interface).
+ *	The notification contains %NL80211_ATTR_NAN_CHANNEL attribute
+ *	identifying the evacuated channel.
+ *	User space may reconfigure the local schedule in response to this
+ *	notification.
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -1678,6 +1687,9 @@ enum nl80211_commands {
 	NL80211_CMD_NAN_SET_PEER_SCHED,
 
 	NL80211_CMD_NAN_ULW_UPDATE,
+
+	NL80211_CMD_NAN_CHANNEL_EVAC,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
@@ -3040,20 +3052,23 @@ enum nl80211_commands {
  *	Currently only supported in mac80211 drivers.
  * @NL80211_ATTR_NAN_CHANNEL: This is a nested attribute. There can be multiple
  *	attributes of this type, each one represents a channel definition and
- *	consists of top-level attributes like %NL80211_ATTR_WIPHY_FREQ. Must
- *	contain %NL80211_ATTR_NAN_CHANNEL_ENTRY and
- *	%NL80211_ATTR_NAN_RX_NSS.
- *	This attribute is used with %NL80211_CMD_NAN_SET_LOCAL_SCHED to specify
+ *	consists of top-level attributes like %NL80211_ATTR_WIPHY_FREQ.
+ *	When used with %NL80211_CMD_NAN_SET_LOCAL_SCHED, it specifies
  *	the channel definitions on which the radio needs to operate during
  *	specific time slots. All of the channel definitions should be mutually
- *	incompatible.
- *	This is also used with %NL80211_CMD_NAN_SET_PEER_SCHED to configure the
+ *	incompatible. With this command, %NL80211_ATTR_NAN_CHANNEL_ENTRY and
+ *	%NL80211_ATTR_NAN_RX_NSS are mandatory.
+ *	When used with %NL80211_CMD_NAN_SET_PEER_SCHED, it configures the
  *	peer NAN channels. In that case, the channel definitions can be
  *	compatible to each other, or even identical just with different RX NSS.
+ *	With this command, %NL80211_ATTR_NAN_CHANNEL_ENTRY and
+ *	%NL80211_ATTR_NAN_RX_NSS are mandatory.
  *	The number of channels should fit the current configuration of channels
  *	and the possible interface combinations.
  *	If an existing NAN channel is changed but the chandef isn't, the
  *	channel entry must also remain unchanged.
+ *	When used with %NL80211_CMD_NAN_CHANNEL_EVAC, this identifies the
+ *	channels that were evacuated.
  * @NL80211_ATTR_NAN_CHANNEL_ENTRY: a byte array of 6 bytes. contains the
  *	Channel Entry as defined in Wi-Fi Aware (TM) 4.0 specification Table
  *	100 (Channel Entry format for the NAN Availability attribute).