Bluetooth: bnep: Add support to extended headers of control frames

Handling extended headers of control frames is required BNEP
functionality. This patch refractor bnep rx frame handling function.
Extended header for control frames shouldn't be omitted as it was
previously done. Every control frame should be checked if it contains
extended header and then every extension should be parsed separately.

Signed-off-by: Grzegorz Kolodziejczyk <[e-mail]>
Signed-off-by: Marcel Holtmann <[e-mail]>

net/bluetooth/bnep/core.c

···
 {
 	struct net_device *dev = s->dev;
 	struct sk_buff *nskb;
-	u8 type;
+	u8 type, ctrl_type;
 
 	dev->stats.rx_bytes += skb->len;
 
 	type = *(u8 *) skb->data;
 	skb_pull(skb, 1);
+	ctrl_type = *(u8 *)skb->data;
 
 	if ((type & BNEP_TYPE_MASK) >= sizeof(__bnep_rx_hlen))
 		goto badframe;
 
 	if ((type & BNEP_TYPE_MASK) == BNEP_CONTROL) {
-		bnep_rx_control(s, skb->data, skb->len);
-		kfree_skb(skb);
-		return 0;
+		if (bnep_rx_control(s, skb->data, skb->len) < 0) {
+			dev->stats.tx_errors++;
+			kfree_skb(skb);
+			return 0;
+		}
+
+		if (!(type & BNEP_EXT_HEADER)) {
+			kfree_skb(skb);
+			return 0;
+		}
+
+		/* Verify and pull ctrl message since it's already processed */
+		switch (ctrl_type) {
+		case BNEP_SETUP_CONN_REQ:
+			/* Pull: ctrl type (1 b), len (1 b), data (len bytes) */
+			if (!skb_pull(skb, 2 + *(u8 *)(skb->data + 1) * 2))
+				goto badframe;
+			break;
+		case BNEP_FILTER_MULTI_ADDR_SET:
+		case BNEP_FILTER_NET_TYPE_SET:
+			/* Pull: ctrl type (1 b), len (2 b), data (len bytes) */
+			if (!skb_pull(skb, 3 + *(u16 *)(skb->data + 1) * 2))
+				goto badframe;
+			break;
+		default:
+			kfree_skb(skb);
+			return 0;
+		}
+	} else {
+		skb_reset_mac_header(skb);
+
+		/* Verify and pull out header */
+		if (!skb_pull(skb, __bnep_rx_hlen[type & BNEP_TYPE_MASK]))
+			goto badframe;
+
+		s->eh.h_proto = get_unaligned((__be16 *) (skb->data - 2));
 	}
-
-	skb_reset_mac_header(skb);
-
-	/* Verify and pull out header */
-	if (!skb_pull(skb, __bnep_rx_hlen[type & BNEP_TYPE_MASK]))
-		goto badframe;
-
-	s->eh.h_proto = get_unaligned((__be16 *) (skb->data - 2));
 
 	if (type & BNEP_EXT_HEADER) {
 		if (bnep_rx_extension(s, skb) < 0)