wifi: mac80211: implement link switching

Implement an API function and debugfs file to switch
active links.

Also provide an async version of the API so drivers
can call it in arbitrary contexts, e.g. while in the
authorized callback.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 171 insertions, 0 deletions

diff --git a/net/mac80211/link.c b/net/mac80211/link.c
index 8df348a5edce..e309708abae8 100644
--- a/net/mac80211/link.c
+++ b/net/mac80211/link.c
@@ -9,6 +9,7 @@
 #include <net/mac80211.h>
 #include "ieee80211_i.h"
 #include "driver-ops.h"
+#include "key.h"
 
 void ieee80211_link_setup(struct ieee80211_link_data *link)
 {
@@ -300,3 +301,173 @@ void ieee80211_vif_clear_links(struct ieee80211_sub_if_data *sdata)
 
 	ieee80211_free_links(sdata, links);
 }
+
+static int _ieee80211_set_active_links(struct ieee80211_sub_if_data *sdata,
+				       u16 active_links)
+{
+	struct ieee80211_bss_conf *link_confs[IEEE80211_MLD_MAX_NUM_LINKS];
+	struct ieee80211_local *local = sdata->local;
+	u16 old_active = sdata->vif.active_links;
+	unsigned long rem = old_active & ~active_links;
+	unsigned long add = active_links & ~old_active;
+	struct sta_info *sta;
+	unsigned int link_id;
+	int ret, i;
+
+	if (!ieee80211_sdata_running(sdata))
+		return -ENETDOWN;
+
+	if (sdata->vif.type != NL80211_IFTYPE_STATION)
+		return -EINVAL;
+
+	/* cannot activate links that don't exist */
+	if (active_links & ~sdata->vif.valid_links)
+		return -EINVAL;
+
+	/* nothing to do */
+	if (old_active == active_links)
+		return 0;
+
+	for (i = 0; i < IEEE80211_MLD_MAX_NUM_LINKS; i++)
+		link_confs[i] = sdata_dereference(sdata->vif.link_conf[i],
+						  sdata);
+
+	if (add) {
+		sdata->vif.active_links |= active_links;
+		ret = drv_change_vif_links(local, sdata,
+					   old_active,
+					   sdata->vif.active_links,
+					   link_confs);
+		if (ret) {
+			sdata->vif.active_links = old_active;
+			return ret;
+		}
+	}
+
+	for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
+		struct ieee80211_link_data *link;
+
+		link = sdata_dereference(sdata->link[link_id], sdata);
+
+		/* FIXME: kill TDLS connections on the link */
+
+		ieee80211_link_release_channel(link);
+	}
+
+	list_for_each_entry(sta, &local->sta_list, list) {
+		if (sdata != sta->sdata)
+			continue;
+		ret = drv_change_sta_links(local, sdata, &sta->sta,
+					   old_active,
+					   old_active | active_links);
+		WARN_ON_ONCE(ret);
+	}
+
+	ret = ieee80211_key_switch_links(sdata, rem, add);
+	WARN_ON_ONCE(ret);
+
+	list_for_each_entry(sta, &local->sta_list, list) {
+		if (sdata != sta->sdata)
+			continue;
+		ret = drv_change_sta_links(local, sdata, &sta->sta,
+					   old_active | active_links,
+					   active_links);
+		WARN_ON_ONCE(ret);
+	}
+
+	for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
+		struct ieee80211_link_data *link;
+
+		link = sdata_dereference(sdata->link[link_id], sdata);
+
+		ret = ieee80211_link_use_channel(link, &link->conf->chandef,
+						 IEEE80211_CHANCTX_SHARED);
+		WARN_ON_ONCE(ret);
+
+		ieee80211_link_info_change_notify(sdata, link,
+						  BSS_CHANGED_ERP_CTS_PROT |
+						  BSS_CHANGED_ERP_PREAMBLE |
+						  BSS_CHANGED_ERP_SLOT |
+						  BSS_CHANGED_HT |
+						  BSS_CHANGED_BASIC_RATES |
+						  BSS_CHANGED_BSSID |
+						  BSS_CHANGED_CQM |
+						  BSS_CHANGED_QOS |
+						  BSS_CHANGED_TXPOWER |
+						  BSS_CHANGED_BANDWIDTH |
+						  BSS_CHANGED_TWT |
+						  BSS_CHANGED_HE_OBSS_PD |
+						  BSS_CHANGED_HE_BSS_COLOR);
+		ieee80211_mgd_set_link_qos_params(link);
+	}
+
+	old_active = sdata->vif.active_links;
+	sdata->vif.active_links = active_links;
+
+	if (rem) {
+		ret = drv_change_vif_links(local, sdata, old_active,
+					   active_links, link_confs);
+		WARN_ON_ONCE(ret);
+	}
+
+	return 0;
+}
+
+int ieee80211_set_active_links(struct ieee80211_vif *vif, u16 active_links)
+{
+	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+	struct ieee80211_local *local = sdata->local;
+	u16 old_active;
+	int ret;
+
+	sdata_lock(sdata);
+	mutex_lock(&local->sta_mtx);
+	mutex_lock(&local->mtx);
+	mutex_lock(&local->key_mtx);
+	old_active = sdata->vif.active_links;
+	if (old_active & active_links) {
+		/*
+		 * if there's at least one link that stays active across
+		 * the change then switch to it (to those) first, and
+		 * then enable the additional links
+		 */
+		ret = _ieee80211_set_active_links(sdata,
+						  old_active & active_links);
+		if (!ret)
+			ret = _ieee80211_set_active_links(sdata, active_links);
+	} else {
+		/* otherwise switch directly */
+		ret = _ieee80211_set_active_links(sdata, active_links);
+	}
+	mutex_unlock(&local->key_mtx);
+	mutex_unlock(&local->mtx);
+	mutex_unlock(&local->sta_mtx);
+	sdata_unlock(sdata);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ieee80211_set_active_links);
+
+void ieee80211_set_active_links_async(struct ieee80211_vif *vif,
+				      u16 active_links)
+{
+	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+
+	if (!ieee80211_sdata_running(sdata))
+		return;
+
+	if (sdata->vif.type != NL80211_IFTYPE_STATION)
+		return;
+
+	/* cannot activate links that don't exist */
+	if (active_links & ~sdata->vif.valid_links)
+		return;
+
+	/* nothing to do */
+	if (sdata->vif.active_links == active_links)
+		return;
+
+	sdata->desired_active_links = active_links;
+	schedule_work(&sdata->activate_links_work);
+}
+EXPORT_SYMBOL_GPL(ieee80211_set_active_links_async);