enic: Check inner ip proto for pseudo header csum

To compute pseudo IP header csum, we need to check the inner header for
encap pkt, not outer IP header.

Also add pseudo csum for IPv6 inner pkt.
Signed-off-by: Govindarajulu Varadarajan <gvaradar@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cisco/enic/enic_main.c

@@ -635,12 +635,25 @@ static int enic_queue_wq_skb_csum_l4(struct enic *enic, struct vnic_wq *wq,
 
 static void enic_preload_tcp_csum_encap(struct sk_buff *skb)
 {
-	if (skb->protocol == cpu_to_be16(ETH_P_IP)) {
+	const struct ethhdr *eth = (struct ethhdr *)skb_inner_mac_header(skb);
+
+	switch (eth->h_proto) {
+	case ntohs(ETH_P_IP):
 		inner_ip_hdr(skb)->check = 0;
 		inner_tcp_hdr(skb)->check =
 			~csum_tcpudp_magic(inner_ip_hdr(skb)->saddr,
 					   inner_ip_hdr(skb)->daddr, 0,
 					   IPPROTO_TCP, 0);
+		break;
+	case ntohs(ETH_P_IPV6):
+		inner_tcp_hdr(skb)->check =
+			~csum_ipv6_magic(&inner_ipv6_hdr(skb)->saddr,
+					 &inner_ipv6_hdr(skb)->daddr, 0,
+					 IPPROTO_TCP, 0);
+		break;
+	default:
+		WARN_ONCE(1, "Non ipv4/ipv6 inner pkt for encap offload");
+		break;
 	}
 }