wifi: mac80211: store BSS param change count from assoc response

When receiving a multi-link association response, make sure to
track the BSS parameter change count for each link, including
the assoc link.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230619161906.1799c164e7e9.I8e2c1f5eec6eec3fab525ae2dead9f6f099a2427@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

include/linux/ieee80211.h

@@ -4689,6 +4689,34 @@ static inline u8 ieee80211_mle_common_size(const u8 *data)
 	return sizeof(*mle) + common + mle->variable[0];
 }
 
+/**
+ * ieee80211_mle_get_bss_param_ch_cnt - returns the BSS parameter change count
+ * @mle: the basic multi link element
+ *
+ * The element is assumed to be of the correct type (BASIC) and big enough,
+ * this must be checked using ieee80211_mle_type_ok().
+ *
+ * If the BSS parameter change count value can't be found (the presence bit
+ * for it is clear), 0 will be returned.
+ */
+static inline u8
+ieee80211_mle_get_bss_param_ch_cnt(const struct ieee80211_multi_link_elem *mle)
+{
+	u16 control = le16_to_cpu(mle->control);
+	const u8 *common = mle->variable;
+
+	/* common points now at the beginning of ieee80211_mle_basic_common_info */
+	common += sizeof(struct ieee80211_mle_basic_common_info);
+
+	if (!(control & IEEE80211_MLC_BASIC_PRES_BSS_PARAM_CH_CNT))
+		return 0;
+
+	if (control & IEEE80211_MLC_BASIC_PRES_LINK_ID)
+		common += 1;
+
+	return *common;
+}
+
 /**
  * ieee80211_mle_get_eml_sync_delay - returns the medium sync delay
  * @data: pointer to the multi link EHT IE
@@ -4902,6 +4930,42 @@ static inline bool ieee80211_mle_basic_sta_prof_size_ok(const u8 *data,
 	       fixed + prof->sta_info_len <= len;
 }
 
+/**
+ * ieee80211_mle_basic_sta_prof_bss_param_ch_cnt - get per-STA profile BSS
+ *	parameter change count
+ * @prof: the per-STA profile, having been checked with
+ *	ieee80211_mle_basic_sta_prof_size_ok() for the correct length
+ *
+ * Return: The BSS parameter change count value if present, 0 otherwise.
+ */
+static inline u8
+ieee80211_mle_basic_sta_prof_bss_param_ch_cnt(const struct ieee80211_mle_per_sta_profile *prof)
+{
+	u16 control = le16_to_cpu(prof->control);
+	const u8 *pos = prof->variable;
+
+	if (!(control & IEEE80211_MLE_STA_CONTROL_BSS_PARAM_CHANGE_CNT_PRESENT))
+		return 0;
+
+	if (control & IEEE80211_MLE_STA_CONTROL_STA_MAC_ADDR_PRESENT)
+		pos += 6;
+	if (control & IEEE80211_MLE_STA_CONTROL_BEACON_INT_PRESENT)
+		pos += 2;
+	if (control & IEEE80211_MLE_STA_CONTROL_TSF_OFFS_PRESENT)
+		pos += 8;
+	if (control & IEEE80211_MLE_STA_CONTROL_DTIM_INFO_PRESENT)
+		pos += 2;
+	if (control & IEEE80211_MLE_STA_CONTROL_COMPLETE_PROFILE &&
+	    control & IEEE80211_MLE_STA_CONTROL_NSTR_BITMAP_SIZE) {
+		if (control & IEEE80211_MLE_STA_CONTROL_NSTR_BITMAP_SIZE)
+			pos += 2;
+		else
+			pos += 1;
+	}
+
+	return *pos;
+}
+
 #define IEEE80211_MLE_STA_RECONF_CONTROL_LINK_ID			0x000f
 #define IEEE80211_MLE_STA_RECONF_CONTROL_COMPLETE_PROFILE		0x0010
 #define IEEE80211_MLE_STA_RECONF_CONTROL_STA_MAC_ADDR_PRESENT		0x0020

net/mac80211/ieee80211_i.h

@@ -951,6 +951,8 @@ struct ieee80211_link_data_managed {
 	int wmm_last_param_set;
 	int mu_edca_last_param_set;
 
+	u8 bss_param_ch_cnt;
+
 	struct cfg80211_bss *bss;
 };
 

net/mac80211/mlme.c

@@ -4018,6 +4018,8 @@ static bool ieee80211_assoc_config_link(struct ieee80211_link_data *link,
 	const struct cfg80211_bss_ies *bss_ies = NULL;
 	struct ieee80211_supported_band *sband;
 	struct ieee802_11_elems *elems;
+	const __le16 prof_bss_param_ch_present =
+		cpu_to_le16(IEEE80211_MLE_STA_CONTROL_BSS_PARAM_CHANGE_CNT_PRESENT);
 	u16 capab_info;
 	bool ret;
 
@@ -4033,7 +4035,17 @@ static bool ieee80211_assoc_config_link(struct ieee80211_link_data *link,
 		 * successful, so set the status directly to success
 		 */
 		assoc_data->link[link_id].status = WLAN_STATUS_SUCCESS;
-	} else if (!elems->prof) {
+		if (elems->ml_basic) {
+			if (!(elems->ml_basic->control &
+					cpu_to_le16(IEEE80211_MLC_BASIC_PRES_BSS_PARAM_CH_CNT))) {
+				ret = false;
+				goto out;
+			}
+			link->u.mgd.bss_param_ch_cnt =
+				ieee80211_mle_get_bss_param_ch_cnt(elems->ml_basic);
+		}
+	} else if (!elems->prof ||
+		   !(elems->prof->control & prof_bss_param_ch_present)) {
 		ret = false;
 		goto out;
 	} else {
@@ -4046,6 +4058,8 @@ static bool ieee80211_assoc_config_link(struct ieee80211_link_data *link,
 		 */
 		capab_info = get_unaligned_le16(ptr);
 		assoc_data->link[link_id].status = get_unaligned_le16(ptr + 2);
+		link->u.mgd.bss_param_ch_cnt =
+			ieee80211_mle_basic_sta_prof_bss_param_ch_cnt(elems->prof);
 
 		if (assoc_data->link[link_id].status != WLAN_STATUS_SUCCESS) {
 			link_info(link, "association response status code=%u\n",