resolved: convert TLSA fields to string

Example output:
_443._tcp.fedoraproject.org IN TLSA  0 0 1 GUAL5bejH7czkXcAeJ0vCiRxwMnVBsDlBMBsFtfLF8A=
                                     -- Cert. usage: CA constraint
                                     -- Selector: Full Certificate
                                     -- Matching type: SHA-256

1 files changed, 30 insertions, 0 deletions

diff --git a/src/resolve/dns-type.c b/src/resolve/dns-type.c
index 56720646ca..46ab694496 100644
--- a/src/resolve/dns-type.c
+++ b/src/resolve/dns-type.c
@@ -228,3 +228,33 @@ int dns_class_from_string(const char *s) {
 
         return _DNS_CLASS_INVALID;
 }
+
+const char* tlsa_cert_usage_to_string(uint8_t cert_usage) {
+        switch(cert_usage) {
+        case 0:         return "CA constraint";
+        case 1:         return "Service certificate constraint";
+        case 2:         return "Trust anchor assertion";
+        case 3:         return "Domain-issued certificate";
+        case 4 ... 254: return "Unassigned";
+        case 255:       return "Private use";
+        }
+}
+
+const char* tlsa_selector_to_string(uint8_t selector) {
+        switch(selector) {
+        case 0:         return "Full Certificate";
+        case 1:         return "SubjectPublicKeyInfo";
+        case 2 ... 254: return "Unassigned";
+        case 255:       return "Private use";
+        }
+}
+
+const char* tlsa_matching_type_to_string(uint8_t selector) {
+        switch(selector) {
+        case 0:         return "No hash used";
+        case 1:         return "SHA-256";
+        case 2:         return "SHA-512";
+        case 3 ... 254: return "Unassigned";
+        case 255:       return "Private use";
+        }
+}