1 files changed, 34 insertions, 10 deletions

diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c
index 6f0d9ec37950..a957c8140721 100644
--- a/net/batman-adv/bridge_loop_avoidance.c
+++ b/net/batman-adv/bridge_loop_avoidance.c
@@ -800,11 +800,6 @@ static int batadv_check_claim_group(struct batadv_priv *bat_priv,
 	bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
 	bla_dst_own = &bat_priv->bla.claim_dest;
 
-	/* check if it is a claim packet in general */
-	if (memcmp(bla_dst->magic, bla_dst_own->magic,
-		   sizeof(bla_dst->magic)) != 0)
-		return 0;
-
 	/* if announcement packet, use the source,
 	 * otherwise assume it is in the hw_src
 	 */
@@ -866,12 +861,13 @@ static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
 				    struct batadv_hard_iface *primary_if,
 				    struct sk_buff *skb)
 {
-	struct batadv_bla_claim_dst *bla_dst;
+	struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
 	uint8_t *hw_src, *hw_dst;
-	struct vlan_ethhdr *vhdr;
+	struct vlan_hdr *vhdr, vhdr_buf;
 	struct ethhdr *ethhdr;
 	struct arphdr *arphdr;
 	unsigned short vid;
+	int vlan_depth = 0;
 	__be16 proto;
 	int headlen;
 	int ret;
@@ -882,9 +878,24 @@ static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
 	proto = ethhdr->h_proto;
 	headlen = ETH_HLEN;
 	if (vid & BATADV_VLAN_HAS_TAG) {
-		vhdr = vlan_eth_hdr(skb);
-		proto = vhdr->h_vlan_encapsulated_proto;
-		headlen += VLAN_HLEN;
+		/* Traverse the VLAN/Ethertypes.
+		 *
+		 * At this point it is known that the first protocol is a VLAN
+		 * header, so start checking at the encapsulated protocol.
+		 *
+		 * The depth of the VLAN headers is recorded to drop BLA claim
+		 * frames encapsulated into multiple VLAN headers (QinQ).
+		 */
+		do {
+			vhdr = skb_header_pointer(skb, headlen, VLAN_HLEN,
+						  &vhdr_buf);
+			if (!vhdr)
+				return 0;
+
+			proto = vhdr->h_vlan_encapsulated_proto;
+			headlen += VLAN_HLEN;
+			vlan_depth++;
+		} while (proto == htons(ETH_P_8021Q));
 	}
 
 	if (proto != htons(ETH_P_ARP))
@@ -914,6 +925,19 @@ static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
 	hw_src = (uint8_t *)arphdr + sizeof(struct arphdr);
 	hw_dst = hw_src + ETH_ALEN + 4;
 	bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
+	bla_dst_own = &bat_priv->bla.claim_dest;
+
+	/* check if it is a claim frame in general */
+	if (memcmp(bla_dst->magic, bla_dst_own->magic,
+		   sizeof(bla_dst->magic)) != 0)
+		return 0;
+
+	/* check if there is a claim frame encapsulated deeper in (QinQ) and
+	 * drop that, as this is not supported by BLA but should also not be
+	 * sent via the mesh.
+	 */
+	if (vlan_depth > 1)
+		return 1;
 
 	/* check if it is a claim frame. */
 	ret = batadv_check_claim_group(bat_priv, primary_if, hw_src, hw_dst,