net: Verify UDP checksum before handoff to encap

Moving validation of UDP checksum to be done in UDP not encap layer.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/udp.c

@@ -1495,6 +1495,10 @@ int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
 			int ret;
 
+			/* Verify checksum before giving to encap */
+			if (udp_lib_checksum_complete(skb))
+				goto csum_error;
+
 			ret = encap_rcv(sk, skb);
 			if (ret <= 0) {
 				UDP_INC_STATS_BH(sock_net(sk),

net/ipv6/udp.c

@@ -634,6 +634,10 @@ int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
 			int ret;
 
+			/* Verify checksum before giving to encap */
+			if (udp_lib_checksum_complete(skb))
+				goto csum_error;
+
 			ret = encap_rcv(sk, skb);
 			if (ret <= 0) {
 				UDP_INC_STATS_BH(sock_net(sk),