implemented helper functions

coolDns.go

@@ -153,31 +153,17 @@ func createServer(zones []zone, config config, aclList map[string]*net.IPNet) *d
 
 			// Parse IP
 			remoteIP, _, err := net.SplitHostPort(w.RemoteAddr().String())
-			if err != nil {
+			ip := net.ParseIP(remoteIP)
+			if err != nil && ip != nil {
 				log.Printf("Faild to parse remote IP WTF? :%s", err.Error())
 				return
 			}
 
-			ip := net.ParseIP(remoteIP)
-
 			// Check ACL rules
-			if len(z.acl) != 0 {
+			if !checkACL(z.acl, aclList, ip) {
-				passed := false
+				rcodeRequest(w, r, dns.RcodeRefused)
-				for _, rule := range z.acl {
-
-					if aclList[rule].Contains(ip) {
-						passed = true
-					}
-				}
-
-				if !passed {
-					m := new(dns.Msg)
-					m.SetReply(r)
-					m.SetRcode(r, dns.RcodeRefused)
-					w.WriteMsg(m)
 				return
 			}
-			}
 
 			m := new(dns.Msg)
 			m.SetReply(r)
@@ -261,32 +247,16 @@ func createServer(zones []zone, config config, aclList map[string]*net.IPNet) *d
 		}
 
 		// Check ACL rules
-		if len(config.Forward.ACL) != 0 {
+		if !checkACL(config.Forward.ACL, aclList, ip) {
-			passed := false
+			rcodeRequest(w, r, dns.RcodeRefused)
-			for _, rule := range config.Forward.ACL {
-
-				if aclList[rule].Contains(ip) {
-					passed = true
-				}
-			}
-
-			if !passed {
-				m := new(dns.Msg)
-				m.SetReply(r)
-				m.SetRcode(r, dns.RcodeRefused)
-				w.WriteMsg(m)
 			return
 		}
-		}
 
 		// Forward request
 		in, _, err := c.Exchange(r, config.Forward.Server)
 
 		if err != nil {
-			m := new(dns.Msg)
+			rcodeRequest(w, r, dns.RcodeServerFailure)
-			m.SetReply(r)
-			m.SetRcode(r, dns.RcodeServerFailure)
-			w.WriteMsg(m)
 			return
 		}
 
@@ -316,6 +286,27 @@ func listenAndServer(server *dns.ServeMux) {
 	os.Exit(0)
 }
 
+func checkACL(alcRules []string, aclList map[string]*net.IPNet, ip net.IP) bool {
+	if len(alcRules) != 0 {
+		passed := false
+		for _, rule := range alcRules {
+
+			if aclList[rule].Contains(ip) {
+				passed = true
+			}
+		}
+		return passed
+	}
+	return true
+}
+
+func rcodeRequest(w dns.ResponseWriter, r *dns.Msg, rcode int) {
+	m := new(dns.Msg)
+	m.SetReply(r)
+	m.SetRcode(r, rcode)
+	w.WriteMsg(m)
+}
+
 func main() {
 	config, err := loadConfig()
 	if err != nil {