wifi: cfg80211: add NL80211_CMD_NAN_SET_NON_EVAC_CHANNELS

Add a new NL80211_CMD_NAN_SET_NON_EVAC_CHANNELS command that lets user
space mark a set of NAN channels as non-evacuable. The command carries
the channels as nested NL80211_ATTR_NAN_CHANNEL attributes (chandef
only) and replaces the entire set of non-evacuable channels; channels
not included in the list become evacuable again.

All provided channels must already exist in the current local schedule,
otherwise -ENOENT is returned. The command is rejected with -EBUSY
while a schedule update is pending.

This prevents the kernel from evacuating channels that carry NDC or
immutable schedules, so evacuating these channels would break existing
NDP connections.

Fixes: 154b0296c0ec ("wifi: nl80211: Add a notification to notify NAN channel evacuation")
Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20260921215936.2efc32011e73.Ice8839058e114f6f9783079807df446388187dda@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 55 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 1ef5f85a9376..0b3fcb2a9576 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -4265,6 +4265,21 @@ struct cfg80211_nan_local_sched {
 };
 
 /**
+ * struct cfg80211_nan_non_evac_channels - NAN non-evacuable channels
+ *
+ * This struct defines the set of NAN local schedule channels that must not
+ * be evacuated for concurrent operations.
+ *
+ * @n_channels: number of channel definitions in %chandefs.
+ * @chandefs: array of channel definitions that must not be evacuated. Each
+ *	must match a channel of the current local schedule.
+ */
+struct cfg80211_nan_non_evac_channels {
+	u8 n_channels;
+	struct cfg80211_chan_def chandefs[] __counted_by(n_channels);
+};
+
+/**
  * struct cfg80211_nan_peer_map - NAN peer schedule map
  *
  * This struct defines a single NAN peer schedule map
@@ -5212,6 +5227,12 @@ struct mgmt_frame_regs {
  *	schedule, the full new schedule is provided - partial updates are not
  *	supported, and the new schedule completely replaces the previous one.
  *
+ * @nan_set_non_evac_channels: set the list of local schedule channels that
+ *	must not be evacuated for concurrent operations. The provided list
+ *	replaces the previous set; channels of the current schedule that are
+ *	not included become evacuable again. All provided channels are
+ *	guaranteed by cfg80211 to belong to the current local schedule.
+ *
  * @set_multicast_to_unicast: configure multicast to unicast conversion for BSS
  *
  * @get_txq_stats: Get TXQ stats for interface or phy. If wdev is %NULL, this
@@ -5601,6 +5622,9 @@ struct cfg80211_ops {
 	int	(*nan_set_peer_sched)(struct wiphy *wiphy,
 				      struct wireless_dev *wdev,
 				      struct cfg80211_nan_peer_sched *sched);
+	int	(*nan_set_non_evac_channels)(struct wiphy *wiphy,
+					     struct wireless_dev *wdev,
+					     struct cfg80211_nan_non_evac_channels *channels);
 	int	(*set_multicast_to_unicast)(struct wiphy *wiphy,
 					    struct net_device *dev,
 					    const bool enabled);
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 843d1dbb725d..be9e2842a736 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1383,6 +1383,13 @@
  *	from the device to perform an announced schedule update. See
  *	%NL80211_ATTR_NAN_SCHED_DEFERRED for more details.
  *	If not set, the schedule should be applied immediately.
+ *	Setting a new schedule is always allowed and is never treated as an
+ *	evacuation, even if it removes channels that were previously marked as
+ *	non-evacuable with %NL80211_CMD_NAN_SET_NON_EVAC_CHANNELS. The
+ *	non-evacuable marking is a per-channel property of the schedule:
+ *	channels that remain in the new schedule keep their marking, channels
+ *	that are removed simply lose it, and newly added channels are
+ *	evacuable by default.
  * @NL80211_CMD_NAN_SCHED_UPDATE_DONE: Event sent to user space to notify that
  *	a deferred local NAN schedule update (requested with
  *	%NL80211_CMD_NAN_SET_LOCAL_SCHED and %NL80211_ATTR_NAN_SCHED_DEFERRED)
@@ -1427,6 +1434,28 @@
  * @NL80211_CMD_STOP_PD: Stop the PD operation, identified by
  *	its %NL80211_ATTR_WDEV interface.
  *
+ * @NL80211_CMD_NAN_SET_NON_EVAC_CHANNELS: Set the list of NAN local schedule
+ *	channels that must not be evacuated. NAN must be operational
+ *	(%NL80211_CMD_START_NAN was executed) and a local schedule must have
+ *	been set (%NL80211_CMD_NAN_SET_LOCAL_SCHED). The command carries zero
+ *	or more nested %NL80211_ATTR_NAN_CHANNEL attributes, each identifying a
+ *	channel (by its channel definition) of the current local schedule that
+ *	must not be evacuated for concurrent operations. The provided list
+ *	replaces the previous set of non-evacuable channels; channels of the
+ *	current schedule that are not included become evacuable again. All
+ *	provided channels must exist in the current local schedule, otherwise
+ *	the command fails. This is used to protect channels carrying NDC or
+ *	immutable schedules, whose evacuation would break existing NDP
+ *	connections.
+ *	The non-evacuable marking is a per-channel property of the current
+ *	local schedule and only affects evacuation for concurrent operations;
+ *	it does not prevent the schedule itself from being changed. Removing a
+ *	channel from the schedule with %NL80211_CMD_NAN_SET_LOCAL_SCHED is a
+ *	user-initiated change, not an evacuation, and is allowed even for a
+ *	non-evacuable channel. Across a schedule update, channels that remain
+ *	keep their non-evacuable marking, removed channels lose it, and newly
+ *	added channels are evacuable by default; issue this command again to
+ *	change the non-evacuable set.
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -1705,6 +1734,8 @@ enum nl80211_commands {
 	NL80211_CMD_START_PD,
 	NL80211_CMD_STOP_PD,
 
+	NL80211_CMD_NAN_SET_NON_EVAC_CHANNELS,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */