openvswitch: Add support for checksums on UDP tunnels.

Currently, it isn't possible to request checksums on the outer UDP
header of tunnels - the TUNNEL_CSUM flag is ignored. This adds
support for requesting that UDP checksums be computed on transmit
and properly reported if they are present on receive.

Signed-off-by: Jesse Gross <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/geneve.h

···
 		    struct sk_buff *skb, __be32 src, __be32 dst, __u8 tos,
 		    __u8 ttl, __be16 df, __be16 src_port, __be16 dst_port,
 		    __be16 tun_flags, u8 vni[3], u8 opt_len, u8 *opt,
-		    bool xnet);
+		    bool csum, bool xnet);
 #endif /*ifdef CONFIG_INET */
 
 #endif /*ifdef__NET_GENEVE_H */

net/ipv4/geneve.c

···
 		    struct sk_buff *skb, __be32 src, __be32 dst, __u8 tos,
 		    __u8 ttl, __be16 df, __be16 src_port, __be16 dst_port,
 		    __be16 tun_flags, u8 vni[3], u8 opt_len, u8 *opt,
-		    bool xnet)
+		    bool csum, bool xnet)
 {
 	struct genevehdr *gnvh;
 	int min_headroom;
 	int err;
 
-	skb = udp_tunnel_handle_offloads(skb, !gs->sock->sk->sk_no_check_tx);
+	skb = udp_tunnel_handle_offloads(skb, csum);
 	if (IS_ERR(skb))
 		return PTR_ERR(skb);
 
···
 
 	return udp_tunnel_xmit_skb(rt, skb, src, dst,
 				   tos, ttl, df, src_port, dst_port, xnet,
-				   gs->sock->sk->sk_no_check_tx);
+				   !csum);
 }
 EXPORT_SYMBOL_GPL(geneve_xmit_skb);
 

net/openvswitch/vport-geneve.c

···
 			      tun_key->ipv4_dst, tun_key->ipv4_tos,
 			      tun_key->ipv4_ttl, df, sport, dport,
 			      tun_key->tun_flags, vni, opts_len, opts,
-			      false);
+			      !!(tun_key->tun_flags & TUNNEL_CSUM), false);
 	if (err < 0)
 		ip_rt_put(rt);
 	return err;

net/openvswitch/vport-vxlan.c

···
 	__be64 key;
 	__be16 flags;
 
-	flags = TUNNEL_KEY;
+	flags = TUNNEL_KEY | (udp_hdr(skb)->check != 0 ? TUNNEL_CSUM : 0);
 	vxlan_port = vxlan_vport(vport);
 	if (vxlan_port->exts & VXLAN_F_GBP)
 		flags |= TUNNEL_VXLAN_OPT;
···
 	__be16 src_port;
 	__be16 df;
 	int err;
+	u32 vxflags;
 
 	if (unlikely(!OVS_CB(skb)->egress_tun_info)) {
 		err = -EINVAL;
···
 	src_port = udp_flow_src_port(net, skb, 0, 0, true);
 	md.vni = htonl(be64_to_cpu(tun_key->tun_id) << 8);
 	md.gbp = vxlan_ext_gbp(skb);
+	vxflags = vxlan_port->exts |
+		      (tun_key->tun_flags & TUNNEL_CSUM ? VXLAN_F_UDP_CSUM : 0);
 
 	err = vxlan_xmit_skb(rt, skb, fl.saddr, tun_key->ipv4_dst,
 			     tun_key->ipv4_tos, tun_key->ipv4_ttl, df,
 			     src_port, dst_port,
-			     &md, false, vxlan_port->exts);
+			     &md, false, vxflags);
 	if (err < 0)
 		ip_rt_put(rt);
 	return err;