mac802154: don't deliver packets to devices that are down

Only one WPAN devices can be active at any given time, so only deliver
packets to that one interface that is actually up. Multiple monitors may
be up at any given time, but we don't have to deliver to monitors that
are down either.
Signed-off-by: NPhoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/mac802154/monitor.c

@@ -70,7 +70,8 @@ void mac802154_monitors_rx(struct mac802154_priv *priv, struct sk_buff *skb)
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(sdata, &priv->slaves, list) {
-		if (sdata->type != IEEE802154_DEV_MONITOR)
+		if (sdata->type != IEEE802154_DEV_MONITOR ||
+		    !netif_running(sdata->dev))
 			continue;
 
 		skb2 = skb_clone(skb, GFP_ATOMIC);

net/mac802154/rx.c

@@ -64,20 +64,23 @@ mac802154_subif_rx(struct ieee802154_dev *hw, struct sk_buff *skb, u8 lqi)
 
 		if (skb->len < 2) {
 			pr_debug("got invalid frame\n");
-			goto out;
+			goto fail;
 		}
 		crc = crc_ccitt(0, skb->data, skb->len);
 		if (crc) {
 			pr_debug("CRC mismatch\n");
-			goto out;
+			goto fail;
 		}
 		skb_trim(skb, skb->len - 2); /* CRC */
 	}
 
 	mac802154_monitors_rx(priv, skb);
 	mac802154_wpans_rx(priv, skb);
-out:
-	dev_kfree_skb(skb);
+
+	return;
+
+fail:
+	kfree_skb(skb);
 }
 
 static void mac802154_rx_worker(struct work_struct *work)

net/mac802154/wpan.c

@@ -567,7 +567,6 @@ static int mac802154_parse_frame_start(struct sk_buff *skb,
 void mac802154_wpans_rx(struct mac802154_priv *priv, struct sk_buff *skb)
 {
 	int ret;
-	struct sk_buff *sskb;
 	struct mac802154_sub_if_data *sdata;
 	struct ieee802154_hdr hdr;
 
@@ -579,12 +578,16 @@ void mac802154_wpans_rx(struct mac802154_priv *priv, struct sk_buff *skb)
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(sdata, &priv->slaves, list) {
-		if (sdata->type != IEEE802154_DEV_WPAN)
+		if (sdata->type != IEEE802154_DEV_WPAN ||
+		    !netif_running(sdata->dev))
 			continue;
 
-		sskb = skb_clone(skb, GFP_ATOMIC);
-		if (sskb)
-			mac802154_subif_frame(sdata, sskb, &hdr);
+		mac802154_subif_frame(sdata, skb, &hdr);
+		skb = NULL;
+		break;
 	}
 	rcu_read_unlock();
+
+	if (skb)
+		kfree_skb(skb);
 }