datapath: Account for "openvswitch: Add support for checksums on UDP …

…tunnels."

Upstream commit:
    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 <jesse@nicira.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

Upstream: b8693877 ("openvswitch: Add support for checksums on UDP tunnels.")
Signed-off-by: Jesse Gross <jesse@nicira.com>

datapath/linux/compat/include/net/vxlan.h

@@ -77,6 +77,10 @@ struct vxlanhdr_gbp {
 #define VXLAN_F_GBP			0x800
 #endif
 
+#ifndef VXLAN_F_UDP_CSUM
+#define VXLAN_F_UDP_CSUM                0x40
+#endif
+
 #ifndef VXLAN_F_RCV_FLAGS
 #define VXLAN_F_RCV_FLAGS			VXLAN_F_GBP
 #endif

datapath/linux/compat/vxlan.c

@@ -191,8 +191,9 @@ int vxlan_xmit_skb(struct vxlan_sock *vs,
 	struct vxlanhdr *vxh;
 	int min_headroom;
 	int err;
+	bool udp_sum = !!(vxflags & VXLAN_F_UDP_CSUM);
 
-	skb = udp_tunnel_handle_offloads(skb, false, true);
+	skb = udp_tunnel_handle_offloads(skb, udp_sum, true);
 	if (IS_ERR(skb))
 		return PTR_ERR(skb);
 
@@ -224,7 +225,7 @@ int vxlan_xmit_skb(struct vxlan_sock *vs,
 
 	return udp_tunnel_xmit_skb(rt, skb, src, dst, tos,
 				   ttl, df, src_port, dst_port, xnet,
-				   true);
+				   !udp_sum);
 }
 
 static void rcu_free_vs(struct rcu_head *rcu)

datapath/vport-vxlan.c

@@ -72,7 +72,7 @@ static void vxlan_rcv(struct vxlan_sock *vs, struct sk_buff *skb,
 	__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 && md->gbp)
 		flags |= TUNNEL_VXLAN_OPT;
@@ -228,6 +228,7 @@ static int vxlan_tnl_send(struct vport *vport, struct sk_buff *skb)
 	__be32 saddr;
 	__be16 df;
 	int err;
+	u32 vxflags;
 
 	if (unlikely(!OVS_CB(skb)->egress_tun_info)) {
 		err = -EINVAL;
@@ -253,13 +254,15 @@ static int vxlan_tnl_send(struct vport *vport, struct sk_buff *skb)
 	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(vxlan_port->vs, rt, skb,
 			     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;