From: Arran Cudbard-Bell <a.cudbardb@freeradius.org>
Date: Fri, 25 Oct 2024 05:42:49 +0000 (-0600)
Subject: Switch DNS to using custom flag parsers
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=de7fe18e3e54fa6df2c4ac210a39ef2e08e78189;p=thirdparty%2Ffreeradius-server.git

Switch DNS to using custom flag parsers
---

diff --git a/src/protocols/dns/base.c b/src/protocols/dns/base.c
index 439ab1311fc..dc6ee368d2e 100644
--- a/src/protocols/dns/base.c
+++ b/src/protocols/dns/base.c
@@ -73,6 +73,14 @@ fr_dict_attr_autoload_t dns_dict_attr[] = {
 	[FR_DNS_STATEFUL_OPERATION] = "Stateful-Operation",
 };
 
+FR_DICT_ATTR_FLAG_FUNC(fr_dns_attr_flags_t, dns_label)
+FR_DICT_ATTR_FLAG_FUNC(fr_dns_attr_flags_t, uncompressed)
+
+static fr_dict_flag_parser_t const dns_flags[] = {
+	{ L("dns_label"),	{ .func = dict_flag_dns_label } },
+	{ L("uncompressed"),	{ .func = dict_flag_uncompressed } }
+};
+
 #define DECODE_FAIL(_reason) if (reason) *reason = FR_DNS_DECODE_FAIL_ ## _reason
 
 static bool fr_dns_tlv_ok(uint8_t const *p, uint8_t const *end, fr_dns_decode_fail_t *reason)
@@ -432,12 +440,6 @@ void fr_dns_global_free(void)
 	fr_dict_autofree(dns_dict);
 }
 
-static fr_table_num_ordered_t const subtype_table[] = {
-	{ L("dns_label"),			FLAG_ENCODE_DNS_LABEL },
-	{ L("uncompressed"),			FLAG_ENCODE_DNS_LABEL_UNCOMPRESSED },
-};
-
-
 static bool attr_valid(fr_dict_attr_t *da)
 {
 	/*
@@ -448,19 +450,14 @@ static bool attr_valid(fr_dict_attr_t *da)
 		da->flags.is_known_width = true;
 	}
 
-	/*
-	 *	"extra" signifies that subtype is being used by the
-	 *	dictionaries itself.
-	 */
-	if (da->flags.extra || !da->flags.subtype) return true;
-
-	if (da->type != FR_TYPE_STRING) {
-		fr_strerror_const("The 'dns_label' flag can only be used with attributes of type 'string'");
-		return false;
+	if (fr_dns_flag_dns_label(da) || fr_dns_flag_uncompressed(da)) {
+		if (da->type != FR_TYPE_STRING) {
+			fr_strerror_const("The 'dns_label' flag can only be used with attributes of type 'string'");
+			return false;
+		}
+		da->flags.is_known_width = true;	/* Lie so we don't trip up the main validation checks */
 	}
 
-	da->flags.is_known_width = true;
-
 	return true;
 }
 
@@ -469,9 +466,10 @@ fr_dict_protocol_t libfreeradius_dns_dict_protocol = {
 	.name = "dns",
 	.default_type_size = 2,
 	.default_type_length = 2,
-	.subtype_table = subtype_table,
-	.subtype_table_len = NUM_ELEMENTS(subtype_table),
 	.attr = {
+		.flags_table = dns_flags,
+		.flags_table_len = NUM_ELEMENTS(dns_flags),
+		.flags_len = sizeof(fr_dns_attr_flags_t),
 		.valid = attr_valid
 	},
 
diff --git a/src/protocols/dns/dns.h b/src/protocols/dns/dns.h
index 3033910e1bd..8225be8157e 100644
--- a/src/protocols/dns/dns.h
+++ b/src/protocols/dns/dns.h
@@ -70,15 +70,6 @@ typedef struct {
 	uint16_t	arcount;
 } CC_HINT(__packed__) fr_dns_packet_t;
 
-/** subtype values for DHCPv4 and DHCPv6
- *
- */
-enum {
-	FLAG_ENCODE_NONE = 0,				//!< no particular encoding for DNS strings
-	FLAG_ENCODE_DNS_LABEL,				//!< encode as DNS label
-	FLAG_ENCODE_DNS_LABEL_UNCOMPRESSED,    		//!< encode as uncompressed DNS label
-};
-
 typedef struct {
 	TALLOC_CTX		*tmp_ctx;		//!< for temporary things cleaned up during decoding
 	uint8_t const		*packet;		//!< DNS labels can point anywhere in the packet :(
@@ -140,6 +131,19 @@ typedef enum {
 
 #define DNS_HDR_LEN (12)
 
+typedef struct {
+	bool			dns_label;
+	bool			uncompressed;
+} fr_dns_attr_flags_t;
+
+static inline fr_dns_attr_flags_t const *fr_dns_attr_flags(fr_dict_attr_t const *da)
+{
+	return fr_dict_attr_ext(da, FR_DICT_ATTR_EXT_PROTOCOL_SPECIFIC);
+}
+
+#define fr_dns_flag_dns_label(_da)			(fr_dns_attr_flags(_da)->dns_label)
+#define fr_dns_flag_uncompressed(_da)			(fr_dns_attr_flags(_da)->uncompressed)
+
 extern fr_table_num_ordered_t fr_dns_reason_fail_table[];
 extern char const *fr_dns_packet_names[FR_DNS_CODE_MAX];
 extern size_t fr_dns_reason_fail_table_len;
diff --git a/src/protocols/dns/encode.c b/src/protocols/dns/encode.c
index 7007cca77cf..8ae92b99f68 100644
--- a/src/protocols/dns/encode.c
+++ b/src/protocols/dns/encode.c
@@ -152,13 +152,13 @@ static ssize_t encode_value(fr_dbuff_t *dbuff,
 		if (!da->flags.extra) {
 			fr_dbuff_marker_t	last_byte, src;
 
-			fr_assert((da->flags.subtype == FLAG_ENCODE_DNS_LABEL) ||
-				  (da->flags.subtype == FLAG_ENCODE_DNS_LABEL_UNCOMPRESSED));
+			fr_assert(fr_dns_flag_dns_label(da) ||
+				  fr_dns_flag_uncompressed(da));
 
 			fr_dbuff_marker(&last_byte, &work_dbuff);
 			fr_dbuff_marker(&src, &work_dbuff);
 			FR_PROTO_TRACE("encode DNS label %s", vp->vp_strvalue);
-			slen = fr_dns_label_from_value_box_dbuff(&work_dbuff, (da->flags.subtype == FLAG_ENCODE_DNS_LABEL),
+			slen = fr_dns_label_from_value_box_dbuff(&work_dbuff, fr_dns_flag_dns_label(da),
 								 &vp->data, packet_ctx->lb);
 			if (slen < 0) return slen;
 			break;