src: Add support for NFTNL_SET_DESC_CONCAT

To support arbitrary range concatenations, the kernel needs to know
how long each field in the concatenation is. The new libnftnl
NFTNL_SET_DESC_CONCAT set attribute describes this as an array of
lengths, in bytes, of concatenated fields.

While evaluating concatenated expressions, export the datatype size
into the new field_len array, and hand the data over via libnftnl.

Similarly, when data is passed back from libnftnl, parse it into
the set description.

When set data is cloned, we now need to copy the additional fields
in set_clone(), too.

This change depends on the libnftnl patch with title:
  set: Add support for NFTA_SET_DESC_CONCAT attributes

v4: No changes
v3: Rework to use set description data instead of a stand-alone
    attribute
v2: No changes

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

6 files changed, 37 insertions, 5 deletions

diff --git a/include/expression.h b/include/expression.h
index b3e79c49..6196be58 100644
--- a/include/expression.h
+++ b/include/expression.h
@@ -261,6 +261,8 @@ struct expr {
 			struct list_head	expressions;
 			unsigned int		size;
 			uint32_t		set_flags;
+			uint8_t			field_len[NFT_REG32_COUNT];
+			uint8_t			field_count;
 		};
 		struct {
 			/* EXPR_SET_REF */
diff --git a/include/rule.h b/include/rule.h
index d5b31765..a7f106f7 100644
--- a/include/rule.h
+++ b/include/rule.h
@@ -289,7 +289,9 @@ extern struct rule *rule_lookup_by_index(const struct chain *chain,
  * @rg_cache:	cached range element (left)
  * @policy:	set mechanism policy
  * @automerge:	merge adjacents and overlapping elements, if possible
- * @desc:	set mechanism desc
+ * @desc.size:		count of set elements
+ * @desc.field_len:	length of single concatenated fields, bytes
+ * @desc.field_count:	count of concatenated fields
  */
 struct set {
 	struct list_head	list;
@@ -310,6 +312,8 @@ struct set {
 	bool			key_typeof_valid;
 	struct {
 		uint32_t	size;
+		uint8_t		field_len[NFT_REG32_COUNT];
+		uint8_t		field_count;
 	} desc;
 };
 
diff --git a/src/evaluate.c b/src/evaluate.c
index 09dd493f..55591f5f 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -1217,6 +1217,8 @@ static int expr_evaluate_concat(struct eval_ctx *ctx, struct expr **expr,
 	struct expr *i, *next;
 
 	list_for_each_entry_safe(i, next, &(*expr)->expressions, list) {
+		unsigned dsize_bytes;
+
 		if (expr_is_constant(*expr) && dtype && off == 0)
 			return expr_binary_error(ctx->msgs, i, *expr,
 						 "unexpected concat component, "
@@ -1241,6 +1243,9 @@ static int expr_evaluate_concat(struct eval_ctx *ctx, struct expr **expr,
 						 i->dtype->name);
 
 		ntype = concat_subtype_add(ntype, i->dtype->type);
+
+		dsize_bytes = div_round_up(i->dtype->size, BITS_PER_BYTE);
+		(*expr)->field_len[(*expr)->field_count++] = dsize_bytes;
 	}
 
 	(*expr)->flags |= flags;
@@ -3345,9 +3350,12 @@ static int set_evaluate(struct eval_ctx *ctx, struct set *set)
 			return set_key_data_error(ctx, set,
 						  set->key->dtype, type);
 	}
-	if (set->flags & NFT_SET_INTERVAL &&
-	    set->key->etype == EXPR_CONCAT)
-		return set_error(ctx, set, "concatenated types not supported in interval sets");
+
+	if (set->flags & NFT_SET_INTERVAL && set->key->etype == EXPR_CONCAT) {
+		memcpy(&set->desc.field_len, &set->key->field_len,
+		       sizeof(set->desc.field_len));
+		set->desc.field_count = set->key->field_count;
+	}
 
 	if (set_is_datamap(set->flags)) {
 		if (set->data == NULL)
diff --git a/src/mnl.c b/src/mnl.c
index d5bdff29..340380ba 100644
--- a/src/mnl.c
+++ b/src/mnl.c
@@ -905,6 +905,13 @@ int mnl_nft_set_add(struct netlink_ctx *ctx, const struct cmd *cmd,
 	if (set->data)
 		set_key_expression(ctx, set->data, set->flags, udbuf, NFTNL_UDATA_SET_DATA_TYPEOF);
 
+	if (set->desc.field_len[0]) {
+		nftnl_set_set_data(nls, NFTNL_SET_DESC_CONCAT,
+				   set->desc.field_len,
+				   set->desc.field_count *
+				   sizeof(set->desc.field_len[0]));
+	}
+
 	nftnl_set_set_data(nls, NFTNL_SET_USERDATA, nftnl_udata_buf_data(udbuf),
 			   nftnl_udata_buf_len(udbuf));
 	nftnl_udata_buf_free(udbuf);
diff --git a/src/netlink.c b/src/netlink.c
index a9ccebaf..791943b4 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -773,6 +773,17 @@ struct set *netlink_delinearize_set(struct netlink_ctx *ctx,
 	if (nftnl_set_is_set(nls, NFTNL_SET_DESC_SIZE))
 		set->desc.size = nftnl_set_get_u32(nls, NFTNL_SET_DESC_SIZE);
 
+	if (nftnl_set_is_set(nls, NFTNL_SET_DESC_CONCAT)) {
+		uint32_t len = NFT_REG32_COUNT;
+		const uint8_t *data;
+
+		data = nftnl_set_get_data(nls, NFTNL_SET_DESC_CONCAT, &len);
+		if (data) {
+			memcpy(set->desc.field_len, data, len);
+			set->desc.field_count = len;
+		}
+	}
+
 	return set;
 }
 
diff --git a/src/rule.c b/src/rule.c
index 883b0707..4853c4f3 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -337,7 +337,7 @@ struct set *set_clone(const struct set *set)
 	new_set->objtype	= set->objtype;
 	new_set->policy		= set->policy;
 	new_set->automerge	= set->automerge;
-	new_set->desc.size	= set->desc.size;
+	new_set->desc		= set->desc;
 
 	return new_set;
 }