wifi: mac80211: add per-link configuration pointer

Add pointers so we can start using link_id throughout the
code, even if for now only link ID 0 is valid, pointing
to the "built-in" bss_conf, which is used by drivers that
are not aware of MLD.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -1739,6 +1739,8 @@ struct ieee80211_vif_cfg {
  * @cfg: vif configuration, see &struct ieee80211_vif_cfg
  * @bss_conf: BSS configuration for this interface, either our own
  *	or the BSS we're associated to
+ * @link_conf: in case of MLD, the per-link BSS configuration,
+ *	indexed by link ID
  * @addr: address of this interface
  * @p2p: indicates whether this AP or STA interface is a p2p
  *	interface, i.e. a GO or p2p-sta respectively
@@ -1773,6 +1775,7 @@ struct ieee80211_vif {
 	enum nl80211_iftype type;
 	struct ieee80211_vif_cfg cfg;
 	struct ieee80211_bss_conf bss_conf;
+	struct ieee80211_bss_conf *link_conf[IEEE80211_MLD_MAX_NUM_LINKS];
 	u8 addr[ETH_ALEN] __aligned(2);
 	bool p2p;
 

net/mac80211/ieee80211_i.h

@@ -1031,6 +1031,7 @@ struct ieee80211_sub_if_data {
 	} u;
 
 	struct ieee80211_link_data deflink;
+	struct ieee80211_link_data *link[IEEE80211_MLD_MAX_NUM_LINKS];
 
 #ifdef CONFIG_MAC80211_DEBUGFS
 	struct {

net/mac80211/iface.c

@@ -1012,6 +1012,23 @@ static void ieee80211_set_default_queues(struct ieee80211_sub_if_data *sdata)
 	sdata->vif.cab_queue = IEEE80211_INVAL_HW_QUEUE;
 }
 
+static void ieee80211_sdata_init(struct ieee80211_local *local,
+				 struct ieee80211_sub_if_data *sdata)
+{
+	sdata->local = local;
+
+	/*
+	 * Initialize the default link, so we can use link_id 0 for non-MLD,
+	 * and that continues to work for non-MLD-aware drivers that use just
+	 * vif.bss_conf instead of vif.link_conf.
+	 *
+	 * Note that we never change this, so if link ID 0 isn't used in an
+	 * MLD connection, we get a separate allocation for it.
+	 */
+	sdata->vif.link_conf[0] = &sdata->vif.bss_conf;
+	sdata->link[0] = &sdata->deflink;
+}
+
 int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
 {
 	struct ieee80211_sub_if_data *sdata;
@@ -1031,12 +1048,13 @@ int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
 		return -ENOMEM;
 
 	/* set up data */
-	sdata->local = local;
 	sdata->vif.type = NL80211_IFTYPE_MONITOR;
 	snprintf(sdata->name, IFNAMSIZ, "%s-monitor",
 		 wiphy_name(local->hw.wiphy));
 	sdata->wdev.iftype = NL80211_IFTYPE_MONITOR;
 
+	ieee80211_sdata_init(local, sdata);
+
 	ieee80211_set_default_queues(sdata);
 
 	ret = drv_add_interface(local, sdata);
@@ -2074,7 +2092,8 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
 
 	/* initialise type-independent data */
 	sdata->wdev.wiphy = local->hw.wiphy;
-	sdata->local = local;
+
+	ieee80211_sdata_init(local, sdata);
 
 	ieee80211_init_frag_cache(&sdata->frags);