meta: introduce datatype ifname_type

This new datatype is a string subtype.
It will allow us to build named maps/sets using meta keys like 'iifname',
'oifname', 'ibriport' or 'obriport'.

Example:

table inet t {
	set s {
		type ifname
		elements = { "eth0",
			     "eth1" }
	}

	chain c {
		iifname @s accept
		oifname @s accept
	}
}

Signed-off-by: Arturo Borrero Gonzalez <arturo@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

5 files changed, 26 insertions, 16 deletions

diff --git a/src/datatype.c b/src/datatype.c
index 93726caf..324ac802 100644
--- a/src/datatype.c
+++ b/src/datatype.c
@@ -68,6 +68,7 @@ static const struct datatype *datatypes[TYPE_MAX + 1] = {
 	[TYPE_ECN]		= &ecn_type,
 	[TYPE_FIB_ADDR]         = &fib_addr_type,
 	[TYPE_BOOLEAN]		= &boolean_type,
+	[TYPE_IFNAME]		= &ifname_type,
 };
 
 const struct datatype *datatype_lookup(enum datatypes type)
diff --git a/src/evaluate.c b/src/evaluate.c
index e5ad1044..c98749d9 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -245,7 +245,7 @@ static int expr_evaluate_string(struct eval_ctx *ctx, struct expr **exprp)
 		/* We need to reallocate the constant expression with the right
 		 * expression length to avoid problems on big endian.
 		 */
-		value = constant_expr_alloc(&expr->location, &string_type,
+		value = constant_expr_alloc(&expr->location, ctx->ectx.dtype,
 					    BYTEORDER_HOST_ENDIAN,
 					    expr->len, data);
 		expr_free(expr);
@@ -260,20 +260,20 @@ static int expr_evaluate_string(struct eval_ctx *ctx, struct expr **exprp)
 		memset(unescaped_str, 0, sizeof(unescaped_str));
 		xstrunescape(data, unescaped_str);
 
-		value = constant_expr_alloc(&expr->location, &string_type,
+		value = constant_expr_alloc(&expr->location, ctx->ectx.dtype,
 					    BYTEORDER_HOST_ENDIAN,
 					    expr->len, unescaped_str);
 		expr_free(expr);
 		*exprp = value;
 		return 0;
 	}
-	value = constant_expr_alloc(&expr->location, &string_type,
+	value = constant_expr_alloc(&expr->location, ctx->ectx.dtype,
 				    BYTEORDER_HOST_ENDIAN,
 				    datalen * BITS_PER_BYTE, data);
 
 	prefix = prefix_expr_alloc(&expr->location, value,
 				   datalen * BITS_PER_BYTE);
-	prefix->dtype = &string_type;
+	prefix->dtype = ctx->ectx.dtype;
 	prefix->flags |= EXPR_F_CONSTANT;
 	prefix->byteorder = BYTEORDER_HOST_ENDIAN;
 
@@ -1769,6 +1769,7 @@ static int expr_evaluate_meta(struct eval_ctx *ctx, struct expr **exprp)
 	    meta->meta.key == NFT_META_NFPROTO)
 		return expr_error(ctx->msgs, meta,
 					  "meta nfproto is only useful in the inet family");
+
 	return expr_evaluate_primary(ctx, exprp);
 }
 
diff --git a/src/meta.c b/src/meta.c
index 8c2eca27..11de2dab 100644
--- a/src/meta.c
+++ b/src/meta.c
@@ -369,6 +369,15 @@ const struct datatype devgroup_type = {
 	.flags		= DTYPE_F_PREFIX,
 };
 
+const struct datatype ifname_type = {
+	.type		= TYPE_IFNAME,
+	.name		= "ifname",
+	.desc		= "network interface name",
+	.byteorder	= BYTEORDER_HOST_ENDIAN,
+	.size		= IFNAMSIZ * BITS_PER_BYTE,
+	.basetype	= &string_type,
+};
+
 static const struct meta_template meta_templates[] = {
 	[NFT_META_LEN]		= META_TEMPLATE("length",    &integer_type,
 						4 * 8, BYTEORDER_HOST_ENDIAN),
@@ -384,14 +393,14 @@ static const struct meta_template meta_templates[] = {
 						4 * 8, BYTEORDER_HOST_ENDIAN),
 	[NFT_META_IIF]		= META_TEMPLATE("iif",       &ifindex_type,
 						4 * 8, BYTEORDER_HOST_ENDIAN),
-	[NFT_META_IIFNAME]	= META_TEMPLATE("iifname",   &string_type,
+	[NFT_META_IIFNAME]	= META_TEMPLATE("iifname",   &ifname_type,
 						IFNAMSIZ * BITS_PER_BYTE,
 						BYTEORDER_HOST_ENDIAN),
 	[NFT_META_IIFTYPE]	= META_TEMPLATE("iiftype",   &arphrd_type,
 						2 * 8, BYTEORDER_HOST_ENDIAN),
 	[NFT_META_OIF]		= META_TEMPLATE("oif",	     &ifindex_type,
 						4 * 8, BYTEORDER_HOST_ENDIAN),
-	[NFT_META_OIFNAME]	= META_TEMPLATE("oifname",   &string_type,
+	[NFT_META_OIFNAME]	= META_TEMPLATE("oifname",   &ifname_type,
 						IFNAMSIZ * BITS_PER_BYTE,
 						BYTEORDER_HOST_ENDIAN),
 	[NFT_META_OIFTYPE]	= META_TEMPLATE("oiftype",   &arphrd_type,
@@ -404,10 +413,10 @@ static const struct meta_template meta_templates[] = {
 						1    , BYTEORDER_HOST_ENDIAN),
 	[NFT_META_RTCLASSID]	= META_TEMPLATE("rtclassid", &realm_type,
 						4 * 8, BYTEORDER_HOST_ENDIAN),
-	[NFT_META_BRI_IIFNAME]	= META_TEMPLATE("ibriport",  &string_type,
+	[NFT_META_BRI_IIFNAME]	= META_TEMPLATE("ibriport",  &ifname_type,
 						IFNAMSIZ * BITS_PER_BYTE,
 						BYTEORDER_HOST_ENDIAN),
-	[NFT_META_BRI_OIFNAME]	= META_TEMPLATE("obriport",  &string_type,
+	[NFT_META_BRI_OIFNAME]	= META_TEMPLATE("obriport",  &ifname_type,
 						IFNAMSIZ * BITS_PER_BYTE,
 						BYTEORDER_HOST_ENDIAN),
 	[NFT_META_PKTTYPE]	= META_TEMPLATE("pkttype",   &pkttype_type,
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index 622425ee..a1f0e923 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -271,9 +271,8 @@ static void netlink_parse_cmp(struct netlink_parse_ctx *ctx,
 	right = netlink_alloc_value(loc, &nld);
 
 	if (left->len > right->len &&
-	    left->dtype != &string_type) {
-		return netlink_error(ctx, loc,
-				     "Relational expression size mismatch");
+	    expr_basetype(left) != &string_type) {
+		return netlink_error(ctx, loc, "Relational expression size mismatch");
 	} else if (left->len > 0 && left->len < right->len) {
 		left = netlink_parse_concat_expr(ctx, loc, sreg, right->len);
 		if (left == NULL)
@@ -1728,7 +1727,7 @@ static struct expr *string_wildcard_expr_alloc(struct location *loc,
 	data[pos] = '*';
 	data[pos + 1] = '\0';
 
-	return constant_expr_alloc(loc, &string_type, BYTEORDER_HOST_ENDIAN,
+	return constant_expr_alloc(loc, expr->dtype, BYTEORDER_HOST_ENDIAN,
 				   expr->len + BITS_PER_BYTE, data);
 }
 
@@ -1744,7 +1743,7 @@ static void escaped_string_wildcard_expr_alloc(struct expr **exprp,
 	data[pos - 1] = '\\';
 	data[pos] = '*';
 
-	tmp = constant_expr_alloc(&expr->location, &string_type,
+	tmp = constant_expr_alloc(&expr->location, expr->dtype,
 				  BYTEORDER_HOST_ENDIAN,
 				  expr->len + BITS_PER_BYTE, data);
 	expr_free(expr);
@@ -1789,7 +1788,7 @@ static struct expr *expr_postprocess_string(struct expr *expr)
 {
 	struct expr *mask;
 
-	assert(expr->dtype->type == TYPE_STRING);
+	assert(expr_basetype(expr)->type == TYPE_STRING);
 	if (__expr_postprocess_string(&expr))
 		return expr;
 
@@ -1893,7 +1892,7 @@ static void expr_postprocess(struct rule_pp_ctx *ctx, struct expr **exprp)
 		if (expr->byteorder == BYTEORDER_HOST_ENDIAN)
 			mpz_switch_byteorder(expr->value, expr->len / BITS_PER_BYTE);
 
-		if (expr->dtype->type == TYPE_STRING)
+		if (expr_basetype(expr)->type == TYPE_STRING)
 			*exprp = expr_postprocess_string(expr);
 
 		if (expr->dtype->basetype != NULL &&
diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index 99a4dde2..77abdcb8 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -364,7 +364,7 @@ static void netlink_gen_cmp(struct netlink_linearize_ctx *ctx,
 		return netlink_gen_lookup(ctx, expr, dreg);
 	case EXPR_PREFIX:
 		sreg = get_register(ctx, expr->left);
-		if (expr->left->dtype->type != TYPE_STRING) {
+		if (expr_basetype(expr->left)->type != TYPE_STRING) {
 			len = div_round_up(expr->right->len, BITS_PER_BYTE);
 			netlink_gen_expr(ctx, expr->left, sreg);
 			right = netlink_gen_prefix(ctx, expr, sreg);