cfg80211: Allow reassociation to be requested with internal SME

If the user space issues a NL80211_CMD_CONNECT with
NL80211_ATTR_PREV_BSSID when there is already a connection, allow this
to proceed as a reassociation instead of rejecting the new connect
command with EALREADY.
Signed-off-by: NJouni Malinen <jouni@qca.qualcomm.com>
[validate prev_bssid]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -8151,7 +8151,8 @@ static int nl80211_connect(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	wdev_lock(dev->ieee80211_ptr);
-	err = cfg80211_connect(rdev, dev, &connect, connkeys, NULL);
+	err = cfg80211_connect(rdev, dev, &connect, connkeys,
+			       connect.prev_bssid);
 	wdev_unlock(dev->ieee80211_ptr);
 	if (err)
 		kzfree(connkeys);

net/wireless/sme.c

@@ -492,8 +492,18 @@ static int cfg80211_sme_connect(struct wireless_dev *wdev,
 	if (!rdev->ops->auth || !rdev->ops->assoc)
 		return -EOPNOTSUPP;
 
-	if (wdev->current_bss)
-		return -EALREADY;
+	if (wdev->current_bss) {
+		if (!prev_bssid)
+			return -EALREADY;
+		if (prev_bssid &&
+		    !ether_addr_equal(prev_bssid, wdev->current_bss->pub.bssid))
+			return -ENOTCONN;
+		cfg80211_unhold_bss(wdev->current_bss);
+		cfg80211_put_bss(wdev->wiphy, &wdev->current_bss->pub);
+		wdev->current_bss = NULL;
+
+		cfg80211_sme_free(wdev);
+	}
 
 	if (WARN_ON(wdev->conn))
 		return -EINPROGRESS;