netfilter: nf_tables: enable set expiration time for set elements

Currently, the expiration of every element in a set or map
is a read-only parameter generated at kernel side.

This change will permit to set a certain expiration date
per element that will be required, for example, during
stateful replication among several nodes.

This patch handles the NFTA_SET_ELEM_EXPIRATION in order
to configure the expiration parameter per element, or
will use the timeout in the case that the expiration
is not set.

Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_tables.h

@@ -636,7 +636,7 @@ static inline struct nft_object **nft_set_ext_obj(const struct nft_set_ext *ext)
 void *nft_set_elem_init(const struct nft_set *set,
 			const struct nft_set_ext_tmpl *tmpl,
 			const u32 *key, const u32 *data,
-			u64 timeout, gfp_t gfp);
+			u64 timeout, u64 expiration, gfp_t gfp);
 void nft_set_elem_destroy(const struct nft_set *set, void *elem,
 			  bool destroy_expr);
 

net/netfilter/nf_tables_api.c

@@ -3873,6 +3873,7 @@ static const struct nla_policy nft_set_elem_policy[NFTA_SET_ELEM_MAX + 1] = {
 	[NFTA_SET_ELEM_DATA]		= { .type = NLA_NESTED },
 	[NFTA_SET_ELEM_FLAGS]		= { .type = NLA_U32 },
 	[NFTA_SET_ELEM_TIMEOUT]		= { .type = NLA_U64 },
+	[NFTA_SET_ELEM_EXPIRATION]	= { .type = NLA_U64 },
 	[NFTA_SET_ELEM_USERDATA]	= { .type = NLA_BINARY,
 					    .len = NFT_USERDATA_MAXLEN },
 	[NFTA_SET_ELEM_EXPR]		= { .type = NLA_NESTED },
@@ -4326,7 +4327,7 @@ static struct nft_trans *nft_trans_elem_alloc(struct nft_ctx *ctx,
 void *nft_set_elem_init(const struct nft_set *set,
 			const struct nft_set_ext_tmpl *tmpl,
 			const u32 *key, const u32 *data,
-			u64 timeout, gfp_t gfp)
+			u64 timeout, u64 expiration, gfp_t gfp)
 {
 	struct nft_set_ext *ext;
 	void *elem;
@@ -4341,9 +4342,11 @@ void *nft_set_elem_init(const struct nft_set *set,
 	memcpy(nft_set_ext_key(ext), key, set->klen);
 	if (nft_set_ext_exists(ext, NFT_SET_EXT_DATA))
 		memcpy(nft_set_ext_data(ext), data, set->dlen);
-	if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION))
-		*nft_set_ext_expiration(ext) =
-			get_jiffies_64() + timeout;
+	if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
+		*nft_set_ext_expiration(ext) = get_jiffies_64() + expiration;
+		if (expiration == 0)
+			*nft_set_ext_expiration(ext) += timeout;
+	}
 	if (nft_set_ext_exists(ext, NFT_SET_EXT_TIMEOUT))
 		*nft_set_ext_timeout(ext) = timeout;
 
@@ -4408,6 +4411,7 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 	struct nft_trans *trans;
 	u32 flags = 0;
 	u64 timeout;
+	u64 expiration;
 	u8 ulen;
 	int err;
 
@@ -4451,6 +4455,16 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 		timeout = set->timeout;
 	}
 
+	expiration = 0;
+	if (nla[NFTA_SET_ELEM_EXPIRATION] != NULL) {
+		if (!(set->flags & NFT_SET_TIMEOUT))
+			return -EINVAL;
+		err = nf_msecs_to_jiffies64(nla[NFTA_SET_ELEM_EXPIRATION],
+					    &expiration);
+		if (err)
+			return err;
+	}
+
 	err = nft_data_init(ctx, &elem.key.val, sizeof(elem.key), &d1,
 			    nla[NFTA_SET_ELEM_KEY]);
 	if (err < 0)
@@ -4533,7 +4547,7 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 
 	err = -ENOMEM;
 	elem.priv = nft_set_elem_init(set, &tmpl, elem.key.val.data, data.data,
-				      timeout, GFP_KERNEL);
+				      timeout, expiration, GFP_KERNEL);
 	if (elem.priv == NULL)
 		goto err3;
 
@@ -4735,7 +4749,7 @@ static int nft_del_setelem(struct nft_ctx *ctx, struct nft_set *set,
 
 	err = -ENOMEM;
 	elem.priv = nft_set_elem_init(set, &tmpl, elem.key.val.data, NULL, 0,
-				      GFP_KERNEL);
+				      0, GFP_KERNEL);
 	if (elem.priv == NULL)
 		goto err2;
 

net/netfilter/nft_dynset.c

@@ -60,7 +60,7 @@ static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr,
 	elem = nft_set_elem_init(set, &priv->tmpl,
 				 &regs->data[priv->sreg_key],
 				 &regs->data[priv->sreg_data],
-				 timeout, GFP_ATOMIC);
+				 timeout, 0, GFP_ATOMIC);
 	if (elem == NULL)
 		goto err1;