wifi: nl80211: fixes to FILS discovery updates

Add a new flag 'update' which is set to true during start_ap()
if (and only if) one of the following two conditions are met:
- Userspace passed an empty nested attribute which indicates that
  the feature should be disabled and templates deleted.
- Userspace passed all the parameters for the nested attribute.

Existing configuration will not be changed while the flag
remains false.

Add similar changes for unsolicited broadcast probe response
transmission.
Signed-off-by: Aloka Dixit <quic_alokad@quicinc.com>
Reviewed-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20230727174100.11721-2-quic_alokad@quicinc.comSigned-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -1338,6 +1338,7 @@ struct cfg80211_acl_data {
  * struct cfg80211_fils_discovery - FILS discovery parameters from
  * IEEE Std 802.11ai-2016, Annex C.3 MIB detail.
  *
+ * @update: Set to true if the feature configuration should be updated.
  * @min_interval: Minimum packet interval in TUs (0 - 10000)
  * @max_interval: Maximum packet interval in TUs (0 - 10000)
  * @tmpl_len: Template length
@@ -1345,6 +1346,7 @@ struct cfg80211_acl_data {
  *	frame headers.
  */
 struct cfg80211_fils_discovery {
+	bool update;
 	u32 min_interval;
 	u32 max_interval;
 	size_t tmpl_len;
@@ -1355,6 +1357,7 @@ struct cfg80211_fils_discovery {
  * struct cfg80211_unsol_bcast_probe_resp - Unsolicited broadcast probe
  *	response parameters in 6GHz.
  *
+ * @update: Set to true if the feature configuration should be updated.
  * @interval: Packet interval in TUs. Maximum allowed is 20 TU, as mentioned
  *	in IEEE P802.11ax/D6.0 26.17.2.3.2 - AP behavior for fast passive
  *	scanning
@@ -1362,6 +1365,7 @@ struct cfg80211_fils_discovery {
  * @tmpl: Template data for probe response
  */
 struct cfg80211_unsol_bcast_probe_resp {
+	bool update;
 	u32 interval;
 	size_t tmpl_len;
 	const u8 *tmpl;

include/uapi/linux/nl80211.h

@@ -2690,11 +2690,13 @@ enum nl80211_commands {
  *
  * @NL80211_ATTR_FILS_DISCOVERY: Optional parameter to configure FILS
  *	discovery. It is a nested attribute, see
- *	&enum nl80211_fils_discovery_attributes.
+ *	&enum nl80211_fils_discovery_attributes. Userspace should pass an empty
+ *	nested attribute to disable this feature and delete the templates.
  *
  * @NL80211_ATTR_UNSOL_BCAST_PROBE_RESP: Optional parameter to configure
  *	unsolicited broadcast probe response. It is a nested attribute, see
- *	&enum nl80211_unsol_bcast_probe_resp_attributes.
+ *	&enum nl80211_unsol_bcast_probe_resp_attributes. Userspace should pass an empty
+ *	nested attribute to disable this feature and delete the templates.
  *
  * @NL80211_ATTR_S1G_CAPABILITY: S1G Capability information element (from
  *	association request when used with NL80211_CMD_NEW_STATION)
@@ -7606,7 +7608,7 @@ enum nl80211_iftype_akm_attributes {
  * @NL80211_FILS_DISCOVERY_ATTR_INT_MIN: Minimum packet interval (u32, TU).
  *	Allowed range: 0..10000 (TU = Time Unit)
  * @NL80211_FILS_DISCOVERY_ATTR_INT_MAX: Maximum packet interval (u32, TU).
- *	Allowed range: 0..10000 (TU = Time Unit)
+ *	Allowed range: 0..10000 (TU = Time Unit). If set to 0, the feature is disabled.
  * @NL80211_FILS_DISCOVERY_ATTR_TMPL: Template data for FILS discovery action
  *	frame including the headers.
  *
@@ -7639,7 +7641,8 @@ enum nl80211_fils_discovery_attributes {
  *
  * @NL80211_UNSOL_BCAST_PROBE_RESP_ATTR_INT: Maximum packet interval (u32, TU).
  *	Allowed range: 0..20 (TU = Time Unit). IEEE P802.11ax/D6.0
- *	26.17.2.3.2 (AP behavior for fast passive scanning).
+ *	26.17.2.3.2 (AP behavior for fast passive scanning). If set to 0, the feature is
+ *	disabled.
  * @NL80211_UNSOL_BCAST_PROBE_RESP_ATTR_TMPL: Unsolicited broadcast probe response
  *	frame template (binary).
  *

net/wireless/nl80211.c

@@ -5647,6 +5647,13 @@ static int nl80211_parse_fils_discovery(struct cfg80211_registered_device *rdev,
 	if (ret)
 		return ret;
 
+	if (!tb[NL80211_FILS_DISCOVERY_ATTR_INT_MIN] &&
+	    !tb[NL80211_FILS_DISCOVERY_ATTR_INT_MAX] &&
+	    !tb[NL80211_FILS_DISCOVERY_ATTR_TMPL]) {
+		fd->update = true;
+		return 0;
+	}
+
 	if (!tb[NL80211_FILS_DISCOVERY_ATTR_INT_MIN] ||
 	    !tb[NL80211_FILS_DISCOVERY_ATTR_INT_MAX] ||
 	    !tb[NL80211_FILS_DISCOVERY_ATTR_TMPL])
@@ -5656,7 +5663,7 @@ static int nl80211_parse_fils_discovery(struct cfg80211_registered_device *rdev,
 	fd->tmpl = nla_data(tb[NL80211_FILS_DISCOVERY_ATTR_TMPL]);
 	fd->min_interval = nla_get_u32(tb[NL80211_FILS_DISCOVERY_ATTR_INT_MIN]);
 	fd->max_interval = nla_get_u32(tb[NL80211_FILS_DISCOVERY_ATTR_INT_MAX]);
-
+	fd->update = true;
 	return 0;
 }
 
@@ -5679,6 +5686,12 @@ nl80211_parse_unsol_bcast_probe_resp(struct cfg80211_registered_device *rdev,
 	if (ret)
 		return ret;
 
+	if (!tb[NL80211_UNSOL_BCAST_PROBE_RESP_ATTR_INT] &&
+	    !tb[NL80211_UNSOL_BCAST_PROBE_RESP_ATTR_TMPL]) {
+		presp->update = true;
+		return 0;
+	}
+
 	if (!tb[NL80211_UNSOL_BCAST_PROBE_RESP_ATTR_INT] ||
 	    !tb[NL80211_UNSOL_BCAST_PROBE_RESP_ATTR_TMPL])
 		return -EINVAL;
@@ -5686,6 +5699,7 @@ nl80211_parse_unsol_bcast_probe_resp(struct cfg80211_registered_device *rdev,
 	presp->tmpl = nla_data(tb[NL80211_UNSOL_BCAST_PROBE_RESP_ATTR_TMPL]);
 	presp->tmpl_len = nla_len(tb[NL80211_UNSOL_BCAST_PROBE_RESP_ATTR_TMPL]);
 	presp->interval = nla_get_u32(tb[NL80211_UNSOL_BCAST_PROBE_RESP_ATTR_INT]);
+	presp->update = true;
 	return 0;
 }