json: add flow statement json export + parser

flow statement has no export, its shown as:
".. }, "flow add @ft" ] } }"

With this patch:

".. }, {"flow": {"op": "add", "flowtable": "@ft"}}]}}"

Signed-off-by: Florian Westphal <fw@strlen.de>

include/json.h

@@ -69,6 +69,7 @@ json_t *uid_type_json(const struct expr *expr, struct output_ctx *octx);
 json_t *gid_type_json(const struct expr *expr, struct output_ctx *octx);
 
 json_t *expr_stmt_json(const struct stmt *stmt, struct output_ctx *octx);
+json_t *flow_offload_stmt_json(const struct stmt *stmt, struct output_ctx *octx);
 json_t *payload_stmt_json(const struct stmt *stmt, struct output_ctx *octx);
 json_t *exthdr_stmt_json(const struct stmt *stmt, struct output_ctx *octx);
 json_t *quota_stmt_json(const struct stmt *stmt, struct output_ctx *octx);
@@ -169,6 +170,7 @@ EXPR_PRINT_STUB(uid_type)
 EXPR_PRINT_STUB(gid_type)
 
 STMT_PRINT_STUB(expr)
+STMT_PRINT_STUB(flow_offload)
 STMT_PRINT_STUB(payload)
 STMT_PRINT_STUB(exthdr)
 STMT_PRINT_STUB(quota)

src/ct.c

@@ -578,6 +578,7 @@ static const struct stmt_ops flow_offload_stmt_ops = {
 	.name		= "flow_offload",
 	.print		= flow_offload_stmt_print,
 	.destroy	= flow_offload_stmt_destroy,
+	.json		= flow_offload_stmt_json,
 };
 
 struct stmt *flow_offload_stmt_alloc(const struct location *loc,

src/json.c

@@ -1122,6 +1122,13 @@ json_t *expr_stmt_json(const struct stmt *stmt, struct output_ctx *octx)
 	return expr_print_json(stmt->expr, octx);
 }
 
+json_t *flow_offload_stmt_json(const struct stmt *stmt, struct output_ctx *octx)
+{
+	return json_pack("{s:{s:s, s:s+}}", "flow",
+			 "op", "add", "flowtable",
+			 "@", stmt->flow.table_name);
+}
+
 json_t *payload_stmt_json(const struct stmt *stmt, struct output_ctx *octx)
 {
 	return json_pack("{s: {s:o, s:o}}", "mangle",

src/parser_json.c

@@ -1903,6 +1903,28 @@ out_err:
 	return NULL;
 }
 
+static struct stmt *json_parse_flow_offload_stmt(struct json_ctx *ctx,
+						 const char *key, json_t *value)
+{
+	const char *opstr, *flowtable;
+
+	if (json_unpack_err(ctx, value, "{s:s, s:s}",
+			    "op", &opstr, "flowtable", &flowtable))
+		return NULL;
+
+	if (strcmp(opstr, "add")) {
+		json_error(ctx, "Unknown flow offload statement op '%s'.", opstr);
+		return NULL;
+	}
+
+	if (flowtable[0] != '@') {
+		json_error(ctx, "Illegal flowtable reference in flow offload statement.");
+		return NULL;
+	}
+
+	return flow_offload_stmt_alloc(int_loc, xstrdup(flowtable + 1));
+}
+
 static struct stmt *json_parse_notrack_stmt(struct json_ctx *ctx,
 					const char *key, json_t *value)
 {
@@ -2647,6 +2669,7 @@ static struct stmt *json_parse_stmt(struct json_ctx *ctx, json_t *root)
 		{ "mangle", json_parse_mangle_stmt },
 		{ "quota", json_parse_quota_stmt },
 		{ "limit", json_parse_limit_stmt },
+		{ "flow", json_parse_flow_offload_stmt },
 		{ "fwd", json_parse_fwd_stmt },
 		{ "notrack", json_parse_notrack_stmt },
 		{ "dup", json_parse_dup_stmt },