[dnssec] key id to string

dnssec/src/key.c

@@ -8,6 +8,25 @@
 #include "keytag.h"
 #include "wire.h"
 
+static const char BIN_TO_HEX[] = { '0', '1', '2', '3', '4', '5', '6', '7',
+				   '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
+
+char *dnssec_key_id_to_string(const dnssec_key_id_t key_id)
+{
+	char *str = malloc(DNSSEC_KEY_ID_STRING_SIZE + 1);
+	if (!str) {
+		return NULL;
+	}
+
+	for (int i = 0; i < DNSSEC_KEY_ID_SIZE; i++) {
+		str[2*i]   = BIN_TO_HEX[key_id[i] >> 4];
+		str[2*i+1] = BIN_TO_HEX[key_id[i] & 0x0f];
+	}
+	str[DNSSEC_KEY_ID_STRING_SIZE] = '\0';
+
+	return str;
+}
+
 static bool key_is_valid(const dnssec_key_t *key)
 {
 	/*

dnssec/src/key.h

@@ -26,6 +26,9 @@ typedef enum dnssec_key_digest {
 
 typedef uint8_t dnssec_key_id_t[20];
 #define DNSSEC_KEY_ID_SIZE sizeof(dnssec_key_id_t)
+#define DNSSEC_KEY_ID_STRING_SIZE (2 * DNSSEC_KEY_ID_SIZE)
+
+char *dnssec_key_id_to_string(const dnssec_key_id_t key_id);
 
 // TODO: library internal API
 struct dnssec_key {

dnssec/tests/key.c

@@ -81,5 +81,15 @@ int main(void)
 
 	public_from_dnskey();
 
+	dnssec_key_id_t key_id = {
+		0x17, 0xda, 0x10, 0xb0, 0x18, 0xdf, 0xff, 0xb0, 0x8a, 0x25,
+		0x1e, 0x74, 0xaf, 0x39, 0x75, 0x2a, 0x54, 0x6e, 0x8c, 0x85
+	};
+	char *key_id_str = dnssec_key_id_to_string(key_id);
+	ok(strcmp(key_id_str, "17da10b018dfffb08a251e74af39752a546e8c85") == 0,
+	   "dnssec_key_id_to_string()");
+	free(key_id_str);
+
+
 	return 0;
 }