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From: Aditya Kumar Singh <quic_adisi@quicinc.com>
To: <johannes@sipsolutions.net>
CC: <linux-wireless@vger.kernel.org>, Sriram R <quic_srirrama@quicinc.com>,
        Aditya Kumar Singh <quic_adisi@quicinc.com>
Subject: [PATCH] wifi: mac80211: validate link status before deciding on off channel Tx
Date: Tue, 12 Mar 2024 21:16:20 +0530
Message-ID: <20240312154620.242773-1-quic_adisi@quicinc.com>
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From: Sriram R <quic_srirrama@quicinc.com>

Currently we check the status of bss active flag to see if the AP is
active. But in case of an AP MLD, when some of the links are getting
teardown and some are active, management Tx (like deauthentication) can
be sent on some links before they are brought down as well.

In such cases, the bss active flag might not provide the exact
status of the MLD links. Hence check if any of the links can
be used for management Tx before returning error status.

While at it, when source address is same as the link conf's address and
if userspace requested Tx on a specific link, add changes to use the same
link id if the link bss is matching the requested channel.

Signed-off-by: Sriram R <quic_srirrama@quicinc.com>
Signed-off-by: Aditya Kumar Singh <quic_adisi@quicinc.com>
---
 net/mac80211/offchannel.c | 46 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/offchannel.c b/net/mac80211/offchannel.c
index 221695d841fd..83f6229fe33b 100644
--- a/net/mac80211/offchannel.c
+++ b/net/mac80211/offchannel.c
@@ -774,6 +774,39 @@ int ieee80211_cancel_remain_on_channel(struct wiphy *wiphy,
 	return ieee80211_cancel_roc(local, cookie, false);
 }
 
+static bool ieee80211_is_link_bss_active(struct ieee80211_sub_if_data *sdata,
+					 int link_id)
+{
+	struct ieee80211_link_data *link;
+
+	lockdep_assert_wiphy(sdata->local->hw.wiphy);
+
+	if (!sdata->bss)
+		return false;
+
+	/* This is consolidated status of the MLD or non ML bss */
+	if (sdata->bss->active)
+		return true;
+
+	if (link_id < 0)
+		return false;
+
+	if (!sdata->vif.valid_links)
+		return false;
+
+	if (!(sdata->vif.valid_links & BIT(link_id)))
+		return false;
+
+	link = sdata_dereference(sdata->link[link_id], sdata);
+	if (!link)
+		return false;
+
+	if (sdata_dereference(link->u.ap.beacon, sdata))
+		return true;
+
+	return false;
+}
+
 int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
 		      struct cfg80211_mgmt_tx_params *params, u64 *cookie)
 {
@@ -817,7 +850,7 @@ int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
 	case NL80211_IFTYPE_P2P_GO:
 		if (sdata->vif.type != NL80211_IFTYPE_ADHOC &&
 		    !ieee80211_vif_is_mesh(&sdata->vif) &&
-		    !sdata->bss->active)
+		    !ieee80211_is_link_bss_active(sdata, params->link_id))
 			need_offchan = true;
 
 		rcu_read_lock();
@@ -897,8 +930,17 @@ int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
 				break;
 			}
 
-			if (ether_addr_equal(conf->addr, mgmt->sa))
+			if (ether_addr_equal(conf->addr, mgmt->sa)) {
+				/* If userspace requested Tx on a specific link
+				 * use the same link id if the link bss is matching
+				 * the requested chan.
+				 */
+				if (sdata->vif.valid_links &&
+				    params->link_id >= 0 && params->link_id == i &&
+				    params->chan == chanctx_conf->def.chan)
+					link_id = i;
 				break;
+			}
 
 			chanctx_conf = NULL;
 		}

base-commit: c2b25092864a16c7865e406badedece5cc25fc2b
-- 
2.25.1