openvswitch: support MPLS push and pop for L3 packets

Update Ethernet header only if there is one.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/openvswitch/actions.c

@@ -187,7 +187,8 @@ static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 
 	skb_postpush_rcsum(skb, new_mpls_lse, MPLS_HLEN);
 
-	update_ethertype(skb, eth_hdr(skb), mpls->mpls_ethertype);
+	if (ovs_key_mac_proto(key) == MAC_PROTO_ETHERNET)
+		update_ethertype(skb, eth_hdr(skb), mpls->mpls_ethertype);
 	skb->protocol = mpls->mpls_ethertype;
 
 	invalidate_flow_key(key);
@@ -197,7 +198,6 @@ static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 		    const __be16 ethertype)
 {
-	struct ethhdr *hdr;
 	int err;
 
 	err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
@@ -213,11 +213,15 @@ static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 	skb_reset_mac_header(skb);
 	skb_set_network_header(skb, skb->mac_len);
 
-	/* mpls_hdr() is used to locate the ethertype field correctly in the
-	 * presence of VLAN tags.
-	 */
-	hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN);
-	update_ethertype(skb, hdr, ethertype);
+	if (ovs_key_mac_proto(key) == MAC_PROTO_ETHERNET) {
+		struct ethhdr *hdr;
+
+		/* mpls_hdr() is used to locate the ethertype field correctly in the
+		 * presence of VLAN tags.
+		 */
+		hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN);
+		update_ethertype(skb, hdr, ethertype);
+	}
 	if (eth_p_mpls(skb->protocol))
 		skb->protocol = ethertype;