net: sched: act_tunnel_key: request UDP checksum by default

There's currently no way to request (outer) UDP checksum with
act_tunnel_key. This is problem especially for IPv6. Right now, tunnel_key
action with IPv6 does not work without going through hassles: both sides
have to have udp6zerocsumrx configured on the tunnel interface. This is
obviously not a good solution universally.

It makes more sense to compute the UDP checksum by default even for IPv4.
Just set the default to request the checksum when using act_tunnel_key.
Signed-off-by: NJiri Benc <jbenc@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/act_tunnel_key.c

@@ -125,7 +125,7 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 			daddr = nla_get_in_addr(tb[TCA_TUNNEL_KEY_ENC_IPV4_DST]);
 
 			metadata = __ip_tun_set_dst(saddr, daddr, 0, 0,
-						    dst_port, TUNNEL_KEY,
+						    dst_port, TUNNEL_KEY | TUNNEL_CSUM,
 						    key_id, 0);
 		} else if (tb[TCA_TUNNEL_KEY_ENC_IPV6_SRC] &&
 			   tb[TCA_TUNNEL_KEY_ENC_IPV6_DST]) {
@@ -136,7 +136,7 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 			daddr = nla_get_in6_addr(tb[TCA_TUNNEL_KEY_ENC_IPV6_DST]);
 
 			metadata = __ipv6_tun_set_dst(&saddr, &daddr, 0, 0, dst_port,
-						      0, TUNNEL_KEY,
+						      0, TUNNEL_KEY | TUNNEL_CSUM,
 						      key_id, 0);
 		}