netfilter: nft_numgen: cancel register tracking

Random and increment are stateful, each invocation results in fresh output.
Cancel register tracking for these two expressions.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_numgen.c

@@ -85,6 +85,16 @@ static int nft_ng_inc_init(const struct nft_ctx *ctx,
 	return err;
 }
 
+static bool nft_ng_inc_reduce(struct nft_regs_track *track,
+				 const struct nft_expr *expr)
+{
+	const struct nft_ng_inc *priv = nft_expr_priv(expr);
+
+	nft_reg_track_cancel(track, priv->dreg, NFT_REG32_SIZE);
+
+	return false;
+}
+
 static int nft_ng_dump(struct sk_buff *skb, enum nft_registers dreg,
 		       u32 modulus, enum nft_ng_types type, u32 offset)
 {
@@ -172,6 +182,16 @@ static int nft_ng_random_dump(struct sk_buff *skb, const struct nft_expr *expr)
 			   priv->offset);
 }
 
+static bool nft_ng_random_reduce(struct nft_regs_track *track,
+				 const struct nft_expr *expr)
+{
+	const struct nft_ng_random *priv = nft_expr_priv(expr);
+
+	nft_reg_track_cancel(track, priv->dreg, NFT_REG32_SIZE);
+
+	return false;
+}
+
 static struct nft_expr_type nft_ng_type;
 static const struct nft_expr_ops nft_ng_inc_ops = {
 	.type		= &nft_ng_type,
@@ -180,6 +200,7 @@ static const struct nft_expr_ops nft_ng_inc_ops = {
 	.init		= nft_ng_inc_init,
 	.destroy	= nft_ng_inc_destroy,
 	.dump		= nft_ng_inc_dump,
+	.reduce		= nft_ng_inc_reduce,
 };
 
 static const struct nft_expr_ops nft_ng_random_ops = {
@@ -188,6 +209,7 @@ static const struct nft_expr_ops nft_ng_random_ops = {
 	.eval		= nft_ng_random_eval,
 	.init		= nft_ng_random_init,
 	.dump		= nft_ng_random_dump,
+	.reduce		= nft_ng_random_reduce,
 };
 
 static const struct nft_expr_ops *