netfilter: flowtable: add tunnel encap/decap action offload support

This patch add tunnel encap decap action offload in the flowtable
offload.
Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_flow_table_offload.c

@@ -475,10 +475,52 @@ static void flow_offload_redirect(const struct flow_offload *flow,
 	dev_hold(rt->dst.dev);
 }
 
+static void flow_offload_encap_tunnel(const struct flow_offload *flow,
+				      enum flow_offload_tuple_dir dir,
+				      struct nf_flow_rule *flow_rule)
+{
+	struct flow_action_entry *entry;
+	struct dst_entry *dst;
+
+	dst = flow->tuplehash[dir].tuple.dst_cache;
+	if (dst->lwtstate) {
+		struct ip_tunnel_info *tun_info;
+
+		tun_info = lwt_tun_info(dst->lwtstate);
+		if (tun_info && (tun_info->mode & IP_TUNNEL_INFO_TX)) {
+			entry = flow_action_entry_next(flow_rule);
+			entry->id = FLOW_ACTION_TUNNEL_ENCAP;
+			entry->tunnel = tun_info;
+		}
+	}
+}
+
+static void flow_offload_decap_tunnel(const struct flow_offload *flow,
+				      enum flow_offload_tuple_dir dir,
+				      struct nf_flow_rule *flow_rule)
+{
+	struct flow_action_entry *entry;
+	struct dst_entry *dst;
+
+	dst = flow->tuplehash[!dir].tuple.dst_cache;
+	if (dst->lwtstate) {
+		struct ip_tunnel_info *tun_info;
+
+		tun_info = lwt_tun_info(dst->lwtstate);
+		if (tun_info && (tun_info->mode & IP_TUNNEL_INFO_TX)) {
+			entry = flow_action_entry_next(flow_rule);
+			entry->id = FLOW_ACTION_TUNNEL_DECAP;
+		}
+	}
+}
+
 int nf_flow_rule_route_ipv4(struct net *net, const struct flow_offload *flow,
 			    enum flow_offload_tuple_dir dir,
 			    struct nf_flow_rule *flow_rule)
 {
+	flow_offload_decap_tunnel(flow, dir, flow_rule);
+	flow_offload_encap_tunnel(flow, dir, flow_rule);
+
 	if (flow_offload_eth_src(net, flow, dir, flow_rule) < 0 ||
 	    flow_offload_eth_dst(net, flow, dir, flow_rule) < 0)
 		return -1;
@@ -505,6 +547,9 @@ int nf_flow_rule_route_ipv6(struct net *net, const struct flow_offload *flow,
 			    enum flow_offload_tuple_dir dir,
 			    struct nf_flow_rule *flow_rule)
 {
+	flow_offload_decap_tunnel(flow, dir, flow_rule);
+	flow_offload_encap_tunnel(flow, dir, flow_rule);
+
 	if (flow_offload_eth_src(net, flow, dir, flow_rule) < 0 ||
 	    flow_offload_eth_dst(net, flow, dir, flow_rule) < 0)
 		return -1;