mac80211: track whether to use channel contexts

Depending on the driver, channel contexts may be used or
not. If they are used, the driver must have support for
hardware scan and remain-on-channel; otherwise the driver
must not advertise support for multiple channels.

Also prohibit WDS type interfaces when channel contexts
are to be used as there's no clear definition of which
channel they use.

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

1 files changed, 22 insertions, 0 deletions

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index d709a5d..0dd1ea2 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -540,6 +540,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 	struct ieee80211_local *local;
 	int priv_size, i;
 	struct wiphy *wiphy;
+	bool use_chanctx;
 
 	if (WARN_ON(!ops->tx || !ops->start || !ops->stop || !ops->config ||
 		    !ops->add_interface || !ops->remove_interface ||
@@ -555,6 +556,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 	    !!ops->unassign_vif_chanctx;
 	if (WARN_ON(i != 0 && i != 5))
 		return NULL;
+	use_chanctx = i == 5;
 
 	/* Ensure 32-byte alignment of our private data and hw private data.
 	 * We use the wiphy priv data for both our ieee80211_local and for
@@ -606,6 +608,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 	local->hw.priv = (char *)local + ALIGN(sizeof(*local), NETDEV_ALIGN);
 
 	local->ops = ops;
+	local->use_chanctx = use_chanctx;
 
 	/* set up some defaults */
 	local->hw.queues = 1;
@@ -729,6 +732,25 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 	if ((hw->flags & IEEE80211_HW_SCAN_WHILE_IDLE) && !local->ops->hw_scan)
 		return -EINVAL;
 
+	if (!local->use_chanctx) {
+		for (i = 0; i < local->hw.wiphy->n_iface_combinations; i++) {
+			const struct ieee80211_iface_combination *comb;
+
+			comb = &local->hw.wiphy->iface_combinations[i];
+
+			if (comb->num_different_channels > 1)
+				return -EINVAL;
+		}
+
+		/*
+		 * WDS is currently prohibited when channel contexts are used
+		 * because there's no clear definition of which channel WDS
+		 * type interfaces use
+		 */
+		if (local->hw.wiphy->interface_modes & BIT(NL80211_IFTYPE_WDS))
+			return -EINVAL;
+	}
+
 	/* Only HW csum features are currently compatible with mac80211 */
 	feature_whitelist = NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
 			    NETIF_F_HW_CSUM;