resolved: move DNS class utilities to dns-type.c and add more helpers

Let's make DNS class helpers more like DNS type helpers, let's move them
from resolved-dns-rr.[ch] into dns-type.[ch].

This also adds two new calls dns_class_is_pseudo() and
dns_class_is_valid_rr() which operate similar to dns_type_is_pseudo()
and dns_type_is_valid_rr() but for classes instead of types.

This should hopefully make handling of DNS classes and DNS types more
alike.

4 files changed, 50 insertions, 39 deletions

diff --git a/src/resolve/dns-type.c b/src/resolve/dns-type.c
index 8281da3b7c..cc52ef9abe 100644
--- a/src/resolve/dns-type.c
+++ b/src/resolve/dns-type.c
@@ -20,6 +20,7 @@
 ***/
 
 #include "dns-type.h"
+#include "string-util.h"
 
 typedef const struct {
         uint16_t type;
@@ -64,6 +65,10 @@ bool dns_type_is_pseudo(uint16_t type) {
         );
 }
 
+bool dns_class_is_pseudo(uint16_t class) {
+        return class == DNS_TYPE_ANY;
+}
+
 bool dns_type_is_valid_query(uint16_t type) {
 
         /* The types valid as questions in packets */
@@ -85,3 +90,34 @@ bool dns_type_is_valid_rr(uint16_t type) {
                        DNS_TYPE_AXFR,
                        DNS_TYPE_IXFR);
 }
+
+bool dns_class_is_valid_rr(uint16_t class) {
+        return class != DNS_CLASS_ANY;
+}
+
+const char *dns_class_to_string(uint16_t class) {
+
+        switch (class) {
+
+        case DNS_CLASS_IN:
+                return "IN";
+
+        case DNS_CLASS_ANY:
+                return "ANY";
+        }
+
+        return NULL;
+}
+
+int dns_class_from_string(const char *s) {
+
+        if (!s)
+                return _DNS_CLASS_INVALID;
+
+        if (strcaseeq(s, "IN"))
+                return DNS_CLASS_IN;
+        else if (strcaseeq(s, "ANY"))
+                return DNS_CLASS_ANY;
+
+        return _DNS_CLASS_INVALID;
+}
diff --git a/src/resolve/dns-type.h b/src/resolve/dns-type.h
index 038a0d0e54..deb89e9b7e 100644
--- a/src/resolve/dns-type.h
+++ b/src/resolve/dns-type.h
@@ -122,3 +122,17 @@ enum {
 assert_cc(DNS_TYPE_SSHFP == 44);
 assert_cc(DNS_TYPE_TLSA == 52);
 assert_cc(DNS_TYPE_ANY == 255);
+
+/* DNS record classes, see RFC 1035 */
+enum {
+        DNS_CLASS_IN   = 0x01,
+        DNS_CLASS_ANY  = 0xFF,
+        _DNS_CLASS_MAX,
+        _DNS_CLASS_INVALID = -1
+};
+
+bool dns_class_is_pseudo(uint16_t class);
+bool dns_class_is_valid_rr(uint16_t class);
+
+const char *dns_class_to_string(uint16_t type);
+int dns_class_from_string(const char *name);
diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c
index 60a614fb6d..98a3a3351d 100644
--- a/src/resolve/resolved-dns-rr.c
+++ b/src/resolve/resolved-dns-rr.c
@@ -1074,34 +1074,6 @@ int dns_resource_record_to_wire_format(DnsResourceRecord *rr, bool canonical) {
         return 0;
 }
 
-const char *dns_class_to_string(uint16_t class) {
-
-        switch (class) {
-
-        case DNS_CLASS_IN:
-                return "IN";
-
-        case DNS_CLASS_ANY:
-                return "ANY";
-        }
-
-        return NULL;
-}
-
-int dns_class_from_string(const char *s, uint16_t *class) {
-        assert(s);
-        assert(class);
-
-        if (strcaseeq(s, "IN"))
-                *class = DNS_CLASS_IN;
-        else if (strcaseeq(s, "ANY"))
-                *class = DNS_CLASS_ANY;
-        else
-                return -EINVAL;
-
-        return 0;
-}
-
 DnsTxtItem *dns_txt_item_free_all(DnsTxtItem *i) {
         DnsTxtItem *n;
 
diff --git a/src/resolve/resolved-dns-rr.h b/src/resolve/resolved-dns-rr.h
index 8d2bc2dc21..bb50cf6a34 100644
--- a/src/resolve/resolved-dns-rr.h
+++ b/src/resolve/resolved-dns-rr.h
@@ -33,14 +33,6 @@ typedef struct DnsResourceKey DnsResourceKey;
 typedef struct DnsResourceRecord DnsResourceRecord;
 typedef struct DnsTxtItem DnsTxtItem;
 
-/* DNS record classes, see RFC 1035 */
-enum {
-        DNS_CLASS_IN   = 0x01,
-        DNS_CLASS_ANY  = 0xFF,
-        _DNS_CLASS_MAX,
-        _DNS_CLASS_INVALID = -1
-};
-
 /* DNSKEY RR flags */
 #define DNSKEY_FLAG_ZONE_KEY (UINT16_C(1) << 8)
 #define DNSKEY_FLAG_SEP      (UINT16_C(1) << 0)
@@ -270,9 +262,6 @@ int dns_resource_record_to_wire_format(DnsResourceRecord *rr, bool canonical);
 DnsTxtItem *dns_txt_item_free_all(DnsTxtItem *i);
 bool dns_txt_item_equal(DnsTxtItem *a, DnsTxtItem *b);
 
-const char *dns_class_to_string(uint16_t type);
-int dns_class_from_string(const char *name, uint16_t *class);
-
 extern const struct hash_ops dns_resource_key_hash_ops;
 
 const char* dnssec_algorithm_to_string(int i) _const_;