wifi: nl80211: Add NAN Discovery Window (DW) notification

This notification will be used by the device to inform user space
about upcoming DW. When received, user space will be able to prepare
multicast Service Discovery Frames (SDFs) to be transmitted during the
next DW using %NL80211_CMD_FRAME command on the NAN management interface.
The device/driver will take care to transmit the frames in the correct
timing. This allows to implement a synchronized Discovery Engine (DE)
in user space, if the device doesn't support DE offload.
Note that this notification can be sent before the actual DW starts as
long as the driver/device handles the actual timing of the SDF
transmission.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250908140015.0e1d15031bab.I5b1721e61b63910452b3c5cdcdc1e94cb094d4c9@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 61 insertions, 0 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 04679acc8135..d64145746b65 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -547,6 +547,7 @@ nl80211_nan_conf_policy[NL80211_NAN_CONF_ATTR_MAX + 1] = {
 	[NL80211_NAN_CONF_SCAN_DWELL_TIME] = NLA_POLICY_RANGE(NLA_U16, 50, 512),
 	[NL80211_NAN_CONF_DISCOVERY_BEACON_INTERVAL] =
 		NLA_POLICY_RANGE(NLA_U8, 50, 200),
+	[NL80211_NAN_CONF_NOTIFY_DW] = { .type = NLA_FLAG },
 };
 
 static const struct netlink_range_validation nl80211_punct_bitmap_range = {
@@ -15627,6 +15628,11 @@ static int nl80211_parse_nan_conf(struct wiphy *wiphy,
 	if (attrs[NL80211_NAN_CONF_DISCOVERY_BEACON_INTERVAL])
 		conf->discovery_beacon_interval =
 			nla_get_u8(attrs[NL80211_NAN_CONF_DISCOVERY_BEACON_INTERVAL]);
+
+	if (attrs[NL80211_NAN_CONF_NOTIFY_DW])
+		conf->enable_dw_notification =
+			nla_get_flag(attrs[NL80211_NAN_CONF_NOTIFY_DW]);
+
 out:
 	if (!conf->band_cfgs[NL80211_BAND_5GHZ].chan &&
 	    (!conf->bands || conf->bands & BIT(NL80211_BAND_5GHZ))) {
@@ -21764,6 +21770,45 @@ void cfg80211_epcs_changed(struct net_device *netdev, bool enabled)
 }
 EXPORT_SYMBOL(cfg80211_epcs_changed);
 
+void cfg80211_next_nan_dw_notif(struct wireless_dev *wdev,
+				struct ieee80211_channel *chan, gfp_t gfp)
+{
+	struct wiphy *wiphy = wdev->wiphy;
+	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+	struct sk_buff *msg;
+	void *hdr;
+
+	trace_cfg80211_next_nan_dw_notif(wdev, chan);
+
+	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_NEXT_DW_NOTIFICATION);
+	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) ||
+	    nla_put_u32(msg, NL80211_ATTR_WIPHY_FREQ, chan->center_freq))
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+
+	genlmsg_unicast(wiphy_net(wiphy), msg, wdev->owner_nlportid);
+
+	return;
+
+ nla_put_failure:
+	nlmsg_free(msg);
+}
+EXPORT_SYMBOL(cfg80211_next_nan_dw_notif);
+
 /* initialisation/exit functions */
 
 int __init nl80211_init(void)
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 9b6074155d59..ff47e9bffd4f 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -4166,6 +4166,22 @@ TRACE_EVENT(cfg80211_epcs_changed,
 		  WDEV_PR_ARG, __entry->enabled)
 );
 
+TRACE_EVENT(cfg80211_next_nan_dw_notif,
+	TP_PROTO(struct wireless_dev *wdev,
+		 struct ieee80211_channel *chan),
+	TP_ARGS(wdev, chan),
+	TP_STRUCT__entry(
+		WDEV_ENTRY
+		CHAN_ENTRY
+	),
+	TP_fast_assign(
+		WDEV_ASSIGN;
+		CHAN_ASSIGN(chan);
+	),
+	TP_printk(WDEV_PR_FMT " " CHAN_PR_FMT,
+		  WDEV_PR_ARG, CHAN_PR_ARG)
+);
+
 #endif /* !__RDEV_OPS_TRACE || TRACE_HEADER_MULTI_READ */
 
 #undef TRACE_INCLUDE_PATH