wifi: cfg80211: Support association to AP MLD with disabled links

An AP part of an AP MLD might be temporarily disabled, and might be
enabled later. Such a link should be included in the association
exchange, but should not be used until enabled.

Extend the NL80211_CMD_ASSOCIATE to also indicate disabled links.
Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230608163202.c4c61ee4c4a5.I784ef4a0d619fc9120514b5615458fbef3b3684a@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -7,7 +7,7 @@
  * Copyright 2006-2010	Johannes Berg <johannes@sipsolutions.net>
  * Copyright 2013-2014 Intel Mobile Communications GmbH
  * Copyright 2015-2017	Intel Deutschland GmbH
- * Copyright (C) 2018-2021 Intel Corporation
+ * Copyright (C) 2018-2021, 2023 Intel Corporation
  */
 
 #include <linux/ethtool.h>
@@ -2882,11 +2882,14 @@ struct cfg80211_auth_request {
  *	if this is %NULL for a link, that link is not requested
  * @elems: extra elements for the per-STA profile for this link
  * @elems_len: length of the elements
+ * @disabled: If set this link should be included during association etc. but it
+ *	should not be used until enabled by the AP MLD.
  */
 struct cfg80211_assoc_link {
 	struct cfg80211_bss *bss;
 	const u8 *elems;
 	size_t elems_len;
+	bool disabled;
 };
 
 /**

include/uapi/linux/nl80211.h

@@ -11,7 +11,7 @@
  * Copyright 2008 Jouni Malinen <jouni.malinen@atheros.com>
  * Copyright 2008 Colin McCabe <colin@cozybit.com>
  * Copyright 2015-2017	Intel Deutschland GmbH
- * Copyright (C) 2018-2022 Intel Corporation
+ * Copyright (C) 2018-2023 Intel Corporation
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -2805,6 +2805,9 @@ enum nl80211_commands {
  *	index. If the userspace includes more RNR elements than number of
  *	MBSSID elements then these will be added in every EMA beacon.
  *
+ * @NL80211_ATTR_MLO_LINK_DISABLED: Flag attribute indicating that the link is
+ *	disabled.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -3341,6 +3344,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_EMA_RNR_ELEMS,
 
+	NL80211_ATTR_MLO_LINK_DISABLED,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,

net/wireless/nl80211.c

@@ -5,7 +5,7 @@
  * Copyright 2006-2010	Johannes Berg <johannes@sipsolutions.net>
  * Copyright 2013-2014  Intel Mobile Communications GmbH
  * Copyright 2015-2017	Intel Deutschland GmbH
- * Copyright (C) 2018-2022 Intel Corporation
+ * Copyright (C) 2018-2023 Intel Corporation
  */
 
 #include <linux/if.h>
@@ -816,6 +816,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_MAX_HW_TIMESTAMP_PEERS] = { .type = NLA_U16 },
 	[NL80211_ATTR_HW_TIMESTAMP_ENABLED] = { .type = NLA_FLAG },
 	[NL80211_ATTR_EMA_RNR_ELEMS] = { .type = NLA_NESTED },
+	[NL80211_ATTR_MLO_LINK_DISABLED] = { .type = NLA_FLAG },
 };
 
 /* policy for the key attributes */
@@ -11138,6 +11139,9 @@ static int nl80211_associate(struct sk_buff *skb, struct genl_info *info)
 					goto free;
 				}
 			}
+
+			req.links[link_id].disabled =
+				nla_get_flag(attrs[NL80211_ATTR_MLO_LINK_DISABLED]);
 		}
 
 		if (!req.links[req.link_id].bss) {
@@ -11152,6 +11156,13 @@ static int nl80211_associate(struct sk_buff *skb, struct genl_info *info)
 			goto free;
 		}
 
+		if (req.links[req.link_id].disabled) {
+			GENL_SET_ERR_MSG(info,
+					 "cannot have assoc link disabled");
+			err = -EINVAL;
+			goto free;
+		}
+
 		kfree(attrs);
 		attrs = NULL;
 	} else {