1 files changed, 473 insertions, 0 deletions

diff --git a/net/mac80211/link.c b/net/mac80211/link.c
new file mode 100644
index 000000000000..e309708abae8
--- /dev/null
+++ b/net/mac80211/link.c
@@ -0,0 +1,473 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MLO link handling
+ *
+ * Copyright (C) 2022 Intel Corporation
+ */
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <net/mac80211.h>
+#include "ieee80211_i.h"
+#include "driver-ops.h"
+#include "key.h"
+
+void ieee80211_link_setup(struct ieee80211_link_data *link)
+{
+	if (link->sdata->vif.type == NL80211_IFTYPE_STATION)
+		ieee80211_mgd_setup_link(link);
+}
+
+void ieee80211_link_init(struct ieee80211_sub_if_data *sdata,
+			 int link_id,
+			 struct ieee80211_link_data *link,
+			 struct ieee80211_bss_conf *link_conf)
+{
+	bool deflink = link_id < 0;
+
+	if (link_id < 0)
+		link_id = 0;
+
+	rcu_assign_pointer(sdata->vif.link_conf[link_id], link_conf);
+	rcu_assign_pointer(sdata->link[link_id], link);
+
+	link->sdata = sdata;
+	link->link_id = link_id;
+	link->conf = link_conf;
+	link_conf->link_id = link_id;
+
+	INIT_WORK(&link->csa_finalize_work,
+		  ieee80211_csa_finalize_work);
+	INIT_WORK(&link->color_change_finalize_work,
+		  ieee80211_color_change_finalize_work);
+	INIT_LIST_HEAD(&link->assigned_chanctx_list);
+	INIT_LIST_HEAD(&link->reserved_chanctx_list);
+	INIT_DELAYED_WORK(&link->dfs_cac_timer_work,
+			  ieee80211_dfs_cac_timer_work);
+
+	if (!deflink) {
+		switch (sdata->vif.type) {
+		case NL80211_IFTYPE_AP:
+			ether_addr_copy(link_conf->addr,
+					sdata->wdev.links[link_id].addr);
+			link_conf->bssid = link_conf->addr;
+			WARN_ON(!(sdata->wdev.valid_links & BIT(link_id)));
+			break;
+		case NL80211_IFTYPE_STATION:
+			/* station sets the bssid in ieee80211_mgd_setup_link */
+			break;
+		default:
+			WARN_ON(1);
+		}
+	}
+}
+
+void ieee80211_link_stop(struct ieee80211_link_data *link)
+{
+	if (link->sdata->vif.type == NL80211_IFTYPE_STATION)
+		ieee80211_mgd_stop_link(link);
+
+	ieee80211_link_release_channel(link);
+}
+
+struct link_container {
+	struct ieee80211_link_data data;
+	struct ieee80211_bss_conf conf;
+};
+
+static void ieee80211_tear_down_links(struct ieee80211_sub_if_data *sdata,
+				      struct link_container **links, u16 mask)
+{
+	struct ieee80211_link_data *link;
+	LIST_HEAD(keys);
+	unsigned int link_id;
+
+	for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++) {
+		if (!(mask & BIT(link_id)))
+			continue;
+		link = &links[link_id]->data;
+		if (link_id == 0 && !link)
+			link = &sdata->deflink;
+		if (WARN_ON(!link))
+			continue;
+		ieee80211_remove_link_keys(link, &keys);
+		ieee80211_link_stop(link);
+	}
+
+	synchronize_rcu();
+
+	ieee80211_free_key_list(sdata->local, &keys);
+}
+
+static void ieee80211_free_links(struct ieee80211_sub_if_data *sdata,
+				 struct link_container **links)
+{
+	unsigned int link_id;
+
+	for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++)
+		kfree(links[link_id]);
+}
+
+static int ieee80211_check_dup_link_addrs(struct ieee80211_sub_if_data *sdata)
+{
+	unsigned int i, j;
+
+	for (i = 0; i < IEEE80211_MLD_MAX_NUM_LINKS; i++) {
+		struct ieee80211_link_data *link1;
+
+		link1 = sdata_dereference(sdata->link[i], sdata);
+		if (!link1)
+			continue;
+		for (j = i + 1; j < IEEE80211_MLD_MAX_NUM_LINKS; j++) {
+			struct ieee80211_link_data *link2;
+
+			link2 = sdata_dereference(sdata->link[j], sdata);
+			if (!link2)
+				continue;
+
+			if (ether_addr_equal(link1->conf->addr,
+					     link2->conf->addr))
+				return -EALREADY;
+		}
+	}
+
+	return 0;
+}
+
+static void ieee80211_set_vif_links_bitmaps(struct ieee80211_sub_if_data *sdata,
+					    u16 links)
+{
+	sdata->vif.valid_links = links;
+
+	if (!links) {
+		sdata->vif.active_links = 0;
+		return;
+	}
+
+	switch (sdata->vif.type) {
+	case NL80211_IFTYPE_AP:
+		/* in an AP all links are always active */
+		sdata->vif.active_links = links;
+		break;
+	case NL80211_IFTYPE_STATION:
+		if (sdata->vif.active_links)
+			break;
+		WARN_ON(hweight16(links) > 1);
+		sdata->vif.active_links = links;
+		break;
+	default:
+		WARN_ON(1);
+	}
+}
+
+static int ieee80211_vif_update_links(struct ieee80211_sub_if_data *sdata,
+				      struct link_container **to_free,
+				      u16 new_links)
+{
+	u16 old_links = sdata->vif.valid_links;
+	u16 old_active = sdata->vif.active_links;
+	unsigned long add = new_links & ~old_links;
+	unsigned long rem = old_links & ~new_links;
+	unsigned int link_id;
+	int ret;
+	struct link_container *links[IEEE80211_MLD_MAX_NUM_LINKS] = {}, *link;
+	struct ieee80211_bss_conf *old[IEEE80211_MLD_MAX_NUM_LINKS];
+	struct ieee80211_link_data *old_data[IEEE80211_MLD_MAX_NUM_LINKS];
+	bool use_deflink = old_links == 0; /* set for error case */
+
+	sdata_assert_lock(sdata);
+
+	memset(to_free, 0, sizeof(links));
+
+	if (old_links == new_links)
+		return 0;
+
+	/* if there were no old links, need to clear the pointers to deflink */
+	if (!old_links)
+		rem |= BIT(0);
+
+	/* allocate new link structures first */
+	for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
+		link = kzalloc(sizeof(*link), GFP_KERNEL);
+		if (!link) {
+			ret = -ENOMEM;
+			goto free;
+		}
+		links[link_id] = link;
+	}
+
+	/* keep track of the old pointers for the driver */
+	BUILD_BUG_ON(sizeof(old) != sizeof(sdata->vif.link_conf));
+	memcpy(old, sdata->vif.link_conf, sizeof(old));
+	/* and for us in error cases */
+	BUILD_BUG_ON(sizeof(old_data) != sizeof(sdata->link));
+	memcpy(old_data, sdata->link, sizeof(old_data));
+
+	/* grab old links to free later */
+	for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
+		if (rcu_access_pointer(sdata->link[link_id]) != &sdata->deflink) {
+			/*
+			 * we must have allocated the data through this path so
+			 * we know we can free both at the same time
+			 */
+			to_free[link_id] = container_of(rcu_access_pointer(sdata->link[link_id]),
+							typeof(*links[link_id]),
+							data);
+		}
+
+		RCU_INIT_POINTER(sdata->link[link_id], NULL);
+		RCU_INIT_POINTER(sdata->vif.link_conf[link_id], NULL);
+	}
+
+	/* link them into data structures */
+	for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
+		WARN_ON(!use_deflink &&
+			rcu_access_pointer(sdata->link[link_id]) == &sdata->deflink);
+
+		link = links[link_id];
+		ieee80211_link_init(sdata, link_id, &link->data, &link->conf);
+		ieee80211_link_setup(&link->data);
+	}
+
+	if (new_links == 0)
+		ieee80211_link_init(sdata, -1, &sdata->deflink,
+				    &sdata->vif.bss_conf);
+
+	ret = ieee80211_check_dup_link_addrs(sdata);
+	if (!ret) {
+		/* for keys we will not be able to undo this */
+		ieee80211_tear_down_links(sdata, to_free, rem);
+
+		ieee80211_set_vif_links_bitmaps(sdata, new_links);
+
+		/* tell the driver */
+		ret = drv_change_vif_links(sdata->local, sdata,
+					   old_links & old_active,
+					   new_links & sdata->vif.active_links,
+					   old);
+	}
+
+	if (ret) {
+		/* restore config */
+		memcpy(sdata->link, old_data, sizeof(old_data));
+		memcpy(sdata->vif.link_conf, old, sizeof(old));
+		ieee80211_set_vif_links_bitmaps(sdata, old_links);
+		/* and free (only) the newly allocated links */
+		memset(to_free, 0, sizeof(links));
+		goto free;
+	}
+
+	/* use deflink/bss_conf again if and only if there are no more links */
+	use_deflink = new_links == 0;
+
+	goto deinit;
+free:
+	/* if we failed during allocation, only free all */
+	for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++) {
+		kfree(links[link_id]);
+		links[link_id] = NULL;
+	}
+deinit:
+	if (use_deflink)
+		ieee80211_link_init(sdata, -1, &sdata->deflink,
+				    &sdata->vif.bss_conf);
+	return ret;
+}
+
+int ieee80211_vif_set_links(struct ieee80211_sub_if_data *sdata,
+			    u16 new_links)
+{
+	struct link_container *links[IEEE80211_MLD_MAX_NUM_LINKS];
+	int ret;
+
+	ret = ieee80211_vif_update_links(sdata, links, new_links);
+	ieee80211_free_links(sdata, links);
+
+	return ret;
+}
+
+void ieee80211_vif_clear_links(struct ieee80211_sub_if_data *sdata)
+{
+	struct link_container *links[IEEE80211_MLD_MAX_NUM_LINKS];
+
+	/*
+	 * The locking here is different because when we free links
+	 * in the station case we need to be able to cancel_work_sync()
+	 * something that also takes the lock.
+	 */
+
+	sdata_lock(sdata);
+	ieee80211_vif_update_links(sdata, links, 0);
+	sdata_unlock(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);