netfilter: nft_ct: fix expiration getter

We need to compute timeout.expires - jiffies, not the other way around.
Add a helper, another patch can then later change more places in
conntrack code where we currently open-code this.

Will allow us to only change one place later when we remove per-ct timer.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index dd78bea..b6083c3 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -284,6 +284,14 @@ static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
 	return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
 }
 
+/* jiffies until ct expires, 0 if already expired */
+static inline unsigned long nf_ct_expires(const struct nf_conn *ct)
+{
+	long timeout = (long)ct->timeout.expires - (long)jiffies;
+
+	return timeout > 0 ? timeout : 0;
+}
+
 struct kernel_param;
 
 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);