1 files changed, 124 insertions, 0 deletions
diff --git a/src/expr/flow_offload.c b/src/expr/flow_offload.c
new file mode 100644
index 0000000..4fc0563
--- /dev/null
+++ b/src/expr/flow_offload.c
@@ -0,0 +1,124 @@
+#include "internal.h"
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h> /* for memcpy */
+#include <arpa/inet.h>
+#include <errno.h>
+#include <libmnl/libmnl.h>
+#include <linux/netfilter/nf_tables.h>
+#include <libnftnl/rule.h>
+#include <libnftnl/expr.h>
+
+struct nftnl_expr_flow {
+	char			*table_name;
+};
+
+static int nftnl_expr_flow_set(struct nftnl_expr *e, uint16_t type,
+			       const void *data, uint32_t data_len)
+{
+	struct nftnl_expr_flow *flow = nftnl_expr_data(e);
+
+	switch (type) {
+	case NFTNL_EXPR_FLOW_TABLE_NAME:
+		flow->table_name = strdup((const char *)data);
+		if (!flow->table_name)
+			return -1;
+		break;
+	default:
+		return -1;
+	}
+	return 0;
+}
+
+static const void *nftnl_expr_flow_get(const struct nftnl_expr *e,
+				       uint16_t type, uint32_t *data_len)
+{
+	struct nftnl_expr_flow *flow = nftnl_expr_data(e);
+
+	switch(type) {
+	case NFTNL_EXPR_FLOW_TABLE_NAME:
+		*data_len = strlen(flow->table_name) + 1;
+		return flow->table_name;
+	}
+	return NULL;
+}
+
+static int nftnl_expr_flow_cb(const struct nlattr *attr, void *data)
+{
+	const struct nlattr **tb = data;
+	int type = mnl_attr_get_type(attr);
+
+	if (mnl_attr_type_valid(attr, NFTA_FLOW_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch(type) {
+	case NFTA_FLOW_TABLE_NAME:
+		if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
+			abi_breakage();
+		break;
+	}
+
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static void nftnl_expr_flow_build(struct nlmsghdr *nlh,
+				  const struct nftnl_expr *e)
+{
+	struct nftnl_expr_flow *flow = nftnl_expr_data(e);
+
+	if (e->flags & (1 << NFTNL_EXPR_FLOW_TABLE_NAME))
+		mnl_attr_put_strz(nlh, NFTA_FLOW_TABLE_NAME, flow->table_name);
+}
+
+static int nftnl_expr_flow_parse(struct nftnl_expr *e, struct nlattr *attr)
+{
+	struct nftnl_expr_flow *flow = nftnl_expr_data(e);
+	struct nlattr *tb[NFTA_FLOW_MAX+1] = {};
+	int ret = 0;
+
+	if (mnl_attr_parse_nested(attr, nftnl_expr_flow_cb, tb) < 0)
+		return -1;
+
+	if (tb[NFTA_FLOW_TABLE_NAME]) {
+		flow->table_name =
+			strdup(mnl_attr_get_str(tb[NFTA_FLOW_TABLE_NAME]));
+		if (!flow->table_name)
+			return -1;
+		e->flags |= (1 << NFTNL_EXPR_FLOW_TABLE_NAME);
+	}
+
+	return ret;
+}
+
+static int nftnl_expr_flow_snprintf(char *buf, size_t remain,
+				    uint32_t flags, const struct nftnl_expr *e)
+{
+	struct nftnl_expr_flow *l = nftnl_expr_data(e);
+	int offset = 0, ret;
+
+	ret = snprintf(buf, remain, "flowtable %s ", l->table_name);
+	SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+
+	return offset;
+}
+
+static void nftnl_expr_flow_free(const struct nftnl_expr *e)
+{
+	struct nftnl_expr_flow *flow = nftnl_expr_data(e);
+
+	xfree(flow->table_name);
+}
+
+struct expr_ops expr_ops_flow = {
+	.name		= "flow_offload",
+	.alloc_len	= sizeof(struct nftnl_expr_flow),
+	.max_attr	= NFTA_FLOW_MAX,
+	.free		= nftnl_expr_flow_free,
+	.set		= nftnl_expr_flow_set,
+	.get		= nftnl_expr_flow_get,
+	.parse		= nftnl_expr_flow_parse,
+	.build		= nftnl_expr_flow_build,
+	.output		= nftnl_expr_flow_snprintf,
+};