Add logging for DNS error returns from upstream and local configuration.

src/cache.c

@@ -1598,6 +1598,19 @@ void log_query(unsigned int flags, char *name, struct all_addr *addr, char *arg)
     {
       if (flags & F_KEYTAG)
 	sprintf(daemon->addrbuff, arg, addr->addr.log.keytag, addr->addr.log.algo, addr->addr.log.digest);
+      else if (flags & F_RCODE)
+	{
+	  unsigned int rcode = addr->addr.rcode.rcode;
+
+	   if (rcode == SERVFAIL)
+	     dest = "SERVFAIL";
+	   else if (rcode == REFUSED)
+	     dest = "REFUSED";
+	   else if (rcode == NOTIMP)
+	     dest = "not implemented";
+	   else
+	     sprintf(daemon->addrbuff, "%u", rcode);
+	}
       else
 	{
 #ifdef HAVE_IPV6