ct: add support for setting ct mark

This patch adds the possibility to set ct keys using nft. Currently, the
connection mark is supported. This functionality enables creating rules
performing the same action as iptables -j CONNMARK --save-mark. For example:

table ip filter {
	chain postrouting {
		type filter hook postrouting priority 0;
		ip protocol icmp ip daddr 8.8.8.8 ct mark set meta mark
	}
}

My patch is based on the original http://patchwork.ozlabs.org/patch/307677/
by Kristian Evensen <kristian.evensen@gmail.com>.

I simply did a rebase and some testing. To test, I added rules like these:
 counter meta mark set 1 counter
 counter ct mark set mark counter
 counter ct mark 1 counter

The last matching worked as expected, which means the second rule is also
working as expected.

Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Acked-by: Kristian Evensen <kristian.evensen@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index 9d59374c..e80646b6 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -662,6 +662,22 @@ static void netlink_gen_queue_stmt(struct netlink_linearize_ctx *ctx,
 	nft_rule_add_expr(ctx->nlr, nle);
 }
 
+static void netlink_gen_ct_stmt(struct netlink_linearize_ctx *ctx,
+				  const struct stmt *stmt)
+{
+	struct nft_rule_expr *nle;
+	enum nft_registers sreg;
+
+	sreg = get_register(ctx);
+	netlink_gen_expr(ctx, stmt->ct.expr, sreg);
+	release_register(ctx);
+
+	nle = alloc_nft_expr("ct");
+	nft_rule_expr_set_u32(nle, NFT_EXPR_CT_SREG, sreg);
+	nft_rule_expr_set_u32(nle, NFT_EXPR_CT_KEY, stmt->ct.key);
+	nft_rule_add_expr(ctx->nlr, nle);
+}
+
 static void netlink_gen_stmt(struct netlink_linearize_ctx *ctx,
 			     const struct stmt *stmt)
 {
@@ -684,6 +700,8 @@ static void netlink_gen_stmt(struct netlink_linearize_ctx *ctx,
 		return netlink_gen_nat_stmt(ctx, stmt);
 	case STMT_QUEUE:
 		return netlink_gen_queue_stmt(ctx, stmt);
+	case STMT_CT:
+		return netlink_gen_ct_stmt(ctx, stmt);
 	default:
 		BUG("unknown statement type %s\n", stmt->ops->name);
 	}