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>

2 files changed, 66 insertions, 0 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index b5185655e687..d65ebba0970b 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -22936,6 +22936,54 @@ void cfg80211_nan_ulw_update(struct wireless_dev *wdev,
 }
 EXPORT_SYMBOL(cfg80211_nan_ulw_update);
 
+void cfg80211_nan_channel_evac(struct wireless_dev *wdev,
+			       const struct cfg80211_chan_def *chandef,
+			       gfp_t gfp)
+{
+	struct wiphy *wiphy = wdev->wiphy;
+	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+	struct sk_buff *msg;
+	struct nlattr *chan_attr;
+	void *hdr;
+
+	trace_cfg80211_nan_channel_evac(wiphy, wdev, chandef);
+
+	if (!wdev->owner_nlportid)
+		return;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, gfp);
+	if (!msg)
+		return;
+
+	hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_NAN_CHANNEL_EVAC);
+	if (!hdr)
+		goto nla_put_failure;
+
+	if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx) ||
+	    nla_put_u64_64bit(msg, NL80211_ATTR_WDEV, wdev_id(wdev),
+			      NL80211_ATTR_PAD))
+		goto nla_put_failure;
+
+	chan_attr = nla_nest_start(msg, NL80211_ATTR_NAN_CHANNEL);
+	if (!chan_attr)
+		goto nla_put_failure;
+
+	if (nl80211_send_chandef(msg, chandef))
+		goto nla_put_failure;
+
+	nla_nest_end(msg, chan_attr);
+
+	genlmsg_end(msg, hdr);
+
+	genlmsg_unicast(wiphy_net(wiphy), msg, wdev->owner_nlportid);
+
+	return;
+
+ nla_put_failure:
+	nlmsg_free(msg);
+}
+EXPORT_SYMBOL(cfg80211_nan_channel_evac);
+
 /* initialisation/exit functions */
 
 int __init nl80211_init(void)
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 061bb84f1a48..eb5bedf9c92a 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -4363,6 +4363,24 @@ TRACE_EVENT(cfg80211_nan_ulw_update,
 		  __print_array(__get_dynamic_array(ulw),
 				__get_dynamic_array_len(ulw), 1))
 );
+
+TRACE_EVENT(cfg80211_nan_channel_evac,
+	TP_PROTO(struct wiphy *wiphy, struct wireless_dev *wdev,
+		 const struct cfg80211_chan_def *chandef),
+	TP_ARGS(wiphy, wdev, chandef),
+	TP_STRUCT__entry(
+		WDEV_ENTRY
+		WIPHY_ENTRY
+		CHAN_DEF_ENTRY
+	),
+	TP_fast_assign(
+		WDEV_ASSIGN;
+		WIPHY_ASSIGN;
+		CHAN_DEF_ASSIGN(chandef);
+	),
+	TP_printk(WDEV_PR_FMT ", " WIPHY_PR_FMT ", " CHAN_DEF_PR_FMT,
+		  WDEV_PR_ARG, WIPHY_PR_ARG, CHAN_DEF_PR_ARG)
+);
 #endif /* !__RDEV_OPS_TRACE || TRACE_HEADER_MULTI_READ */
 
 #undef TRACE_INCLUDE_PATH