wifi: cfg80211: do some rework towards MLO link APIs

In order to support multi-link operation with multiple links,
start adding some APIs. The notable addition here is to have
the link ID in a new nl80211 attribute, that will be used to
differentiate the links in many nl80211 operations.

So far, this patch adds the netlink NL80211_ATTR_MLO_LINK_ID
attribute (as well as the NL80211_ATTR_MLO_LINKS attribute)
and plugs it through the system in some places, checking the
validity etc. along with other infrastructure needed for it.

For now, I've decided to include only the over-the-air link
ID in the API. I know we discussed that we eventually need to
have to have other ways of identifying a link, but for local
AP mode and auth/assoc commands as well as set_key etc. we'll
use the OTA ID.

Also included in this patch is some refactoring of the data
structures in struct wireless_dev, splitting for the first
time the data into type dependent pieces, to make reasoning
about these things easier.

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

1 files changed, 85 insertions, 54 deletions

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 58e83ce642ad..c7383ede794f 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -5,7 +5,7 @@
  * Copyright 2008-2011	Luis R. Rodriguez <mcgrof@qca.qualcomm.com>
  * Copyright 2013-2014  Intel Mobile Communications GmbH
  * Copyright      2017  Intel Deutschland GmbH
- * Copyright (C) 2018 - 2021 Intel Corporation
+ * Copyright (C) 2018 - 2022 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
@@ -2370,6 +2370,7 @@ static bool reg_wdev_chan_valid(struct wiphy *wiphy, struct wireless_dev *wdev)
 	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 	enum nl80211_iftype iftype;
 	bool ret;
+	int link;
 
 	wdev_lock(wdev);
 	iftype = wdev->iftype;
@@ -2378,62 +2379,83 @@ static bool reg_wdev_chan_valid(struct wiphy *wiphy, struct wireless_dev *wdev)
 	if (!wdev->netdev || !netif_running(wdev->netdev))
 		goto wdev_inactive_unlock;
 
-	switch (iftype) {
-	case NL80211_IFTYPE_AP:
-	case NL80211_IFTYPE_P2P_GO:
-	case NL80211_IFTYPE_MESH_POINT:
-		if (!wdev->beacon_interval)
-			goto wdev_inactive_unlock;
-		chandef = wdev->chandef;
-		break;
-	case NL80211_IFTYPE_ADHOC:
-		if (!wdev->ssid_len)
-			goto wdev_inactive_unlock;
-		chandef = wdev->chandef;
-		break;
-	case NL80211_IFTYPE_STATION:
-	case NL80211_IFTYPE_P2P_CLIENT:
-		if (!wdev->current_bss ||
-		    !wdev->current_bss->pub.channel)
-			goto wdev_inactive_unlock;
-
-		if (!rdev->ops->get_channel ||
-		    rdev_get_channel(rdev, wdev, &chandef))
-			cfg80211_chandef_create(&chandef,
-						wdev->current_bss->pub.channel,
-						NL80211_CHAN_NO_HT);
-		break;
-	case NL80211_IFTYPE_MONITOR:
-	case NL80211_IFTYPE_AP_VLAN:
-	case NL80211_IFTYPE_P2P_DEVICE:
-		/* no enforcement required */
-		break;
-	default:
-		/* others not implemented for now */
-		WARN_ON(1);
-		break;
-	}
+	for (link = 0; link < ARRAY_SIZE(wdev->links); link++) {
+		struct ieee80211_channel *chan;
 
-	wdev_unlock(wdev);
+		if (!wdev->valid_links && link > 0)
+			break;
+		if (!(wdev->valid_links & BIT(link)))
+			continue;
+		switch (iftype) {
+		case NL80211_IFTYPE_AP:
+		case NL80211_IFTYPE_P2P_GO:
+		case NL80211_IFTYPE_MESH_POINT:
+			if (!wdev->u.mesh.beacon_interval)
+				continue;
+			chandef = wdev->u.mesh.chandef;
+			break;
+		case NL80211_IFTYPE_ADHOC:
+			if (!wdev->u.ibss.ssid_len)
+				continue;
+			chandef = wdev->u.ibss.chandef;
+			break;
+		case NL80211_IFTYPE_STATION:
+		case NL80211_IFTYPE_P2P_CLIENT:
+			/* Maybe we could consider disabling that link only? */
+			if (!wdev->links[link].client.current_bss)
+				continue;
 
-	switch (iftype) {
-	case NL80211_IFTYPE_AP:
-	case NL80211_IFTYPE_P2P_GO:
-	case NL80211_IFTYPE_ADHOC:
-	case NL80211_IFTYPE_MESH_POINT:
-		wiphy_lock(wiphy);
-		ret = cfg80211_reg_can_beacon_relax(wiphy, &chandef, iftype);
-		wiphy_unlock(wiphy);
+			chan = wdev->links[link].client.current_bss->pub.channel;
+			if (!chan)
+				continue;
 
-		return ret;
-	case NL80211_IFTYPE_STATION:
-	case NL80211_IFTYPE_P2P_CLIENT:
-		return cfg80211_chandef_usable(wiphy, &chandef,
-					       IEEE80211_CHAN_DISABLED);
-	default:
-		break;
+			if (!rdev->ops->get_channel ||
+			    rdev_get_channel(rdev, wdev, link, &chandef))
+				cfg80211_chandef_create(&chandef, chan,
+							NL80211_CHAN_NO_HT);
+			break;
+		case NL80211_IFTYPE_MONITOR:
+		case NL80211_IFTYPE_AP_VLAN:
+		case NL80211_IFTYPE_P2P_DEVICE:
+			/* no enforcement required */
+			break;
+		default:
+			/* others not implemented for now */
+			WARN_ON(1);
+			break;
+		}
+
+		wdev_unlock(wdev);
+
+		switch (iftype) {
+		case NL80211_IFTYPE_AP:
+		case NL80211_IFTYPE_P2P_GO:
+		case NL80211_IFTYPE_ADHOC:
+		case NL80211_IFTYPE_MESH_POINT:
+			wiphy_lock(wiphy);
+			ret = cfg80211_reg_can_beacon_relax(wiphy, &chandef,
+							    iftype);
+			wiphy_unlock(wiphy);
+
+			if (!ret)
+				return ret;
+			break;
+		case NL80211_IFTYPE_STATION:
+		case NL80211_IFTYPE_P2P_CLIENT:
+			ret = cfg80211_chandef_usable(wiphy, &chandef,
+						      IEEE80211_CHAN_DISABLED);
+			if (!ret)
+				return ret;
+			break;
+		default:
+			break;
+		}
+
+		wdev_lock(wdev);
 	}
 
+	wdev_unlock(wdev);
+
 	return true;
 
 wdev_inactive_unlock:
@@ -4215,8 +4237,17 @@ static void cfg80211_check_and_end_cac(struct cfg80211_registered_device *rdev)
 	 * In both cases we should end the CAC on the wdev.
 	 */
 	list_for_each_entry(wdev, &rdev->wiphy.wdev_list, list) {
-		if (wdev->cac_started &&
-		    !cfg80211_chandef_dfs_usable(&rdev->wiphy, &wdev->chandef))
+		struct cfg80211_chan_def *chandef;
+
+		if (!wdev->cac_started)
+			continue;
+
+		/* FIXME: radar detection is tied to link 0 for now */
+		chandef = wdev_chandef(wdev, 0);
+		if (!chandef)
+			continue;
+
+		if (!cfg80211_chandef_dfs_usable(&rdev->wiphy, chandef))
 			rdev_end_cac(rdev, wdev->netdev);
 	}
 }