{nl,mac}80211: fix interface combinations on crypto controlled devices

Commit 33d915d9e8 ("{nl,mac}80211: allow 4addr AP operation on
crypto controlled devices") has introduced a change which allows
4addr operation on crypto controlled devices (ex: ath10k). This
change has inadvertently impacted the interface combinations logic
on such devices.

General rule is that software interfaces like AP/VLAN should not be
listed under supported interface combinations and should not be
considered during validation of these combinations; because of the
aforementioned change, AP/VLAN interfaces(if present) will be checked
against interfaces supported by the device and blocks valid interface
combinations.

Consider a case where an AP and AP/VLAN are up and running; when a
second AP device is brought up on the same physical device, this AP
will be checked against the AP/VLAN interface (which will not be
part of supported interface combinations of the device) and blocks
second AP to come up.

Add a new API cfg80211_iftype_allowed() to fix the problem, this
API works for all devices with/without SW crypto control.

Signed-off-by: Manikanta Pubbisetty <mpubbise@codeaurora.org>
Fixes: 33d915d9e8 ("{nl,mac}80211: allow 4addr AP operation on crypto controlled devices")
Link: https://lore.kernel.org/r/1563779690-9716-1-git-send-email-mpubbise@codeaurora.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -7320,6 +7320,21 @@ void cfg80211_pmsr_complete(struct wireless_dev *wdev,
 			    struct cfg80211_pmsr_request *req,
 			    gfp_t gfp);
 
+/**
+ * cfg80211_iftype_allowed - check whether the interface can be allowed
+ * @wiphy: the wiphy
+ * @iftype: interface type
+ * @is_4addr: use_4addr flag, must be '0' when check_swif is '1'
+ * @check_swif: check iftype against software interfaces
+ *
+ * Check whether the interface is allowed to operate; additionally, this API
+ * can be used to check iftype against the software interfaces when
+ * check_swif is '1'.
+ */
+bool cfg80211_iftype_allowed(struct wiphy *wiphy, enum nl80211_iftype iftype,
+			     bool is_4addr, u8 check_swif);
+
+
 /* Logging, debugging and troubleshooting/diagnostic helpers. */
 
 /* wiphy_printk helpers, similar to dev_printk */

net/mac80211/util.c

@@ -3796,9 +3796,7 @@ int ieee80211_check_combinations(struct ieee80211_sub_if_data *sdata,
 	}
 
 	/* Always allow software iftypes */
-	if (local->hw.wiphy->software_iftypes & BIT(iftype) ||
-	    (iftype == NL80211_IFTYPE_AP_VLAN &&
-	     local->hw.wiphy->flags & WIPHY_FLAG_4ADDR_AP)) {
+	if (cfg80211_iftype_allowed(local->hw.wiphy, iftype, 0, 1)) {
 		if (radar_detect)
 			return -EINVAL;
 		return 0;
@@ -3833,7 +3831,8 @@ int ieee80211_check_combinations(struct ieee80211_sub_if_data *sdata,
 
 		if (sdata_iter == sdata ||
 		    !ieee80211_sdata_running(sdata_iter) ||
-		    local->hw.wiphy->software_iftypes & BIT(wdev_iter->iftype))
+		    cfg80211_iftype_allowed(local->hw.wiphy,
+					    wdev_iter->iftype, 0, 1))
 			continue;
 
 		params.iftype_num[wdev_iter->iftype]++;

net/wireless/core.c

@@ -1410,10 +1410,8 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
 		}
 		break;
 	case NETDEV_PRE_UP:
-		if (!(wdev->wiphy->interface_modes & BIT(wdev->iftype)) &&
-		    !(wdev->iftype == NL80211_IFTYPE_AP_VLAN &&
-		      rdev->wiphy.flags & WIPHY_FLAG_4ADDR_AP &&
-		      wdev->use_4addr))
+		if (!cfg80211_iftype_allowed(wdev->wiphy, wdev->iftype,
+					     wdev->use_4addr, 0))
 			return notifier_from_errno(-EOPNOTSUPP);
 
 		if (rfkill_blocked(rdev->rfkill))

net/wireless/nl80211.c

@@ -3484,9 +3484,7 @@ static int nl80211_new_interface(struct sk_buff *skb, struct genl_info *info)
 			return err;
 	}
 
-	if (!(rdev->wiphy.interface_modes & (1 << type)) &&
-	    !(type == NL80211_IFTYPE_AP_VLAN && params.use_4addr &&
-	      rdev->wiphy.flags & WIPHY_FLAG_4ADDR_AP))
+	if (!cfg80211_iftype_allowed(&rdev->wiphy, type, params.use_4addr, 0))
 		return -EOPNOTSUPP;
 
 	err = nl80211_parse_mon_options(rdev, type, info, &params);

net/wireless/util.c

@@ -1697,7 +1697,7 @@ int cfg80211_iter_combinations(struct wiphy *wiphy,
 	for (iftype = 0; iftype < NUM_NL80211_IFTYPES; iftype++) {
 		num_interfaces += params->iftype_num[iftype];
 		if (params->iftype_num[iftype] > 0 &&
-		    !(wiphy->software_iftypes & BIT(iftype)))
+		    !cfg80211_iftype_allowed(wiphy, iftype, 0, 1))
 			used_iftypes |= BIT(iftype);
 	}
 
@@ -1719,7 +1719,7 @@ int cfg80211_iter_combinations(struct wiphy *wiphy,
 			return -ENOMEM;
 
 		for (iftype = 0; iftype < NUM_NL80211_IFTYPES; iftype++) {
-			if (wiphy->software_iftypes & BIT(iftype))
+			if (cfg80211_iftype_allowed(wiphy, iftype, 0, 1))
 				continue;
 			for (j = 0; j < c->n_limits; j++) {
 				all_iftypes |= limits[j].types;
@@ -2072,3 +2072,26 @@ int ieee80211_get_vht_max_nss(struct ieee80211_vht_cap *cap,
 	return max_vht_nss;
 }
 EXPORT_SYMBOL(ieee80211_get_vht_max_nss);
+
+bool cfg80211_iftype_allowed(struct wiphy *wiphy, enum nl80211_iftype iftype,
+			     bool is_4addr, u8 check_swif)
+
+{
+	bool is_vlan = iftype == NL80211_IFTYPE_AP_VLAN;
+
+	switch (check_swif) {
+	case 0:
+		if (is_vlan && is_4addr)
+			return wiphy->flags & WIPHY_FLAG_4ADDR_AP;
+		return wiphy->interface_modes & BIT(iftype);
+	case 1:
+		if (!(wiphy->software_iftypes & BIT(iftype)) && is_vlan)
+			return wiphy->flags & WIPHY_FLAG_4ADDR_AP;
+		return wiphy->software_iftypes & BIT(iftype);
+	default:
+		break;
+	}
+
+	return false;
+}
+EXPORT_SYMBOL(cfg80211_iftype_allowed);