src: flow offload support

This patch allows us to refer to existing flowtables:

 # nft add rule x x flow offload @m

Packets matching this rule create an entry in the flow table 'm', hence,
follow up packets that get to the flowtable at ingress bypass the
classic forwarding path.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

2 files changed, 11 insertions, 0 deletions

diff --git a/include/ct.h b/include/ct.h
index ec5d55d8..2c3392d3 100644
--- a/include/ct.h
+++ b/include/ct.h
@@ -29,6 +29,8 @@ extern struct expr *ct_expr_alloc(const struct location *loc,
 extern void ct_expr_update_type(struct proto_ctx *ctx, struct expr *expr);
 
 extern struct stmt *notrack_stmt_alloc(const struct location *loc);
+extern struct stmt *flow_offload_stmt_alloc(const struct location *loc,
+					    const char *table_name);
 
 extern const struct datatype ct_dir_type;
 extern const struct datatype ct_state_type;
diff --git a/include/statement.h b/include/statement.h
index 379d99e4..27c73567 100644
--- a/include/statement.h
+++ b/include/statement.h
@@ -10,6 +10,12 @@ extern struct stmt *expr_stmt_alloc(const struct location *loc,
 extern struct stmt *verdict_stmt_alloc(const struct location *loc,
 				       struct expr *expr);
 
+struct flow_stmt {
+	const char		*table_name;
+};
+
+struct stmt *flow_stmt_alloc(const struct location *loc, const char *name);
+
 struct objref_stmt {
 	uint32_t		type;
 	struct expr		*expr;
@@ -231,6 +237,7 @@ extern struct stmt *xt_stmt_alloc(const struct location *loc);
  * @STMT_NOTRACK:	notrack statement
  * @STMT_OBJREF:	stateful object reference statement
  * @STMT_EXTHDR:	extension header statement
+ * @STMT_FLOW_OFFLOAD:	flow offload statement
  */
 enum stmt_types {
 	STMT_INVALID,
@@ -256,6 +263,7 @@ enum stmt_types {
 	STMT_NOTRACK,
 	STMT_OBJREF,
 	STMT_EXTHDR,
+	STMT_FLOW_OFFLOAD,
 };
 
 /**
@@ -316,6 +324,7 @@ struct stmt {
 		struct fwd_stmt		fwd;
 		struct xt_stmt		xt;
 		struct objref_stmt	objref;
+		struct flow_stmt	flow;
 	};
 };