+/*
+ * Check if hostname is numerical.
+ * Returns -1 if hostname is numeric, 0 otherwise
+ */
+static int
+is_numeric_hostname(const char *hostname)
+{
+ struct addrinfo hints, *ai;
+
+ /*
+ * We shouldn't ever get a null host but if we do then log an error
+ * and return -1 which stops DNS key fingerprint processing.
+ */
+ if (hostname == NULL) {
+ error("is_numeric_hostname called with NULL hostname");
+ return -1;
+ }
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_socktype = SOCK_DGRAM;
+ hints.ai_flags = AI_NUMERICHOST;
+
+ if (getaddrinfo(hostname, NULL, &hints, &ai) == 0) {
+ freeaddrinfo(ai);
+ return -1;
+ }
+
+ return 0;
+}