netfilter: nft_dynset: fix element timeout for HZ != 1000

With HZ=100 element timeout in dynamic sets (i.e. flow tables) is 10 times
higher than configured.

Add proper conversion to/from jiffies, when interacting with userspace.

I tested this on Linux 4.8.1, and it applies cleanly to current nf and
nf-next trees.

Fixes: 22fe54d ("netfilter: nf_tables: add support for dynamic set updates")
Signed-off-by: Anders K. Pedersen <akp@cohaesio.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_dynset.c

@@ -158,7 +158,8 @@ static int nft_dynset_init(const struct nft_ctx *ctx,
 	if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
 		if (!(set->flags & NFT_SET_TIMEOUT))
 			return -EINVAL;
-		timeout = be64_to_cpu(nla_get_be64(tb[NFTA_DYNSET_TIMEOUT]));
+		timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64(
+						tb[NFTA_DYNSET_TIMEOUT])));
 	}
 
 	priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]);
@@ -246,7 +247,8 @@ static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr)
 		goto nla_put_failure;
 	if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
 		goto nla_put_failure;
-	if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT, cpu_to_be64(priv->timeout),
+	if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
+			 cpu_to_be64(jiffies_to_msecs(priv->timeout)),
 			 NFTA_DYNSET_PAD))
 		goto nla_put_failure;
 	if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr))