netfilter: nft_quota: add quota object update support

Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_quota.c

@@ -13,7 +13,7 @@
 #include <net/netfilter/nf_tables.h>
 
 struct nft_quota {
-	u64		quota;
+	atomic64_t	quota;
 	unsigned long	flags;
 	atomic64_t	consumed;
 };
@@ -21,7 +21,8 @@ struct nft_quota {
 static inline bool nft_overquota(struct nft_quota *priv,
 				 const struct sk_buff *skb)
 {
-	return atomic64_add_return(skb->len, &priv->consumed) >= priv->quota;
+	return atomic64_add_return(skb->len, &priv->consumed) >=
+	       atomic64_read(&priv->quota);
 }
 
 static inline bool nft_quota_invert(struct nft_quota *priv)
@@ -89,7 +90,7 @@ static int nft_quota_do_init(const struct nlattr * const tb[],
 			return -EOPNOTSUPP;
 	}
 
-	priv->quota = quota;
+	atomic64_set(&priv->quota, quota);
 	priv->flags = flags;
 	atomic64_set(&priv->consumed, consumed);
 
@@ -105,10 +106,22 @@ static int nft_quota_obj_init(const struct nft_ctx *ctx,
 	return nft_quota_do_init(tb, priv);
 }
 
+static void nft_quota_obj_update(struct nft_object *obj,
+				 struct nft_object *newobj)
+{
+	struct nft_quota *newpriv = nft_obj_data(newobj);
+	struct nft_quota *priv = nft_obj_data(obj);
+	u64 newquota;
+
+	newquota = atomic64_read(&newpriv->quota);
+	atomic64_set(&priv->quota, newquota);
+	priv->flags = newpriv->flags;
+}
+
 static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv,
 			     bool reset)
 {
-	u64 consumed, consumed_cap;
+	u64 consumed, consumed_cap, quota;
 	u32 flags = priv->flags;
 
 	/* Since we inconditionally increment consumed quota for each packet
@@ -116,14 +129,15 @@ static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv,
 	 * userspace.
 	 */
 	consumed = atomic64_read(&priv->consumed);
-	if (consumed >= priv->quota) {
-		consumed_cap = priv->quota;
+	quota = atomic64_read(&priv->quota);
+	if (consumed >= quota) {
+		consumed_cap = quota;
 		flags |= NFT_QUOTA_F_DEPLETED;
 	} else {
 		consumed_cap = consumed;
 	}
 
-	if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(priv->quota),
+	if (nla_put_be64(skb, NFTA_QUOTA_BYTES, cpu_to_be64(quota),
 			 NFTA_QUOTA_PAD) ||
 	    nla_put_be64(skb, NFTA_QUOTA_CONSUMED, cpu_to_be64(consumed_cap),
 			 NFTA_QUOTA_PAD) ||
@@ -155,6 +169,7 @@ static const struct nft_object_ops nft_quota_obj_ops = {
 	.init		= nft_quota_obj_init,
 	.eval		= nft_quota_obj_eval,
 	.dump		= nft_quota_obj_dump,
+	.update		= nft_quota_obj_update,
 };
 
 static struct nft_object_type nft_quota_obj_type __read_mostly = {