Add support for allow/deny clients by IP (#355)

cmd/mc-router/main.go

@@ -53,6 +53,9 @@ type Config struct {
 	RoutesConfig          string `usage:"Name or full path to routes config file"`
 	NgrokToken            string `usage:"If set, an ngrok tunnel will be established. It is HIGHLY recommended to pass as an environment variable."`
 
+	ClientsToAllow []string `usage:"Zero or more client IP addresses or CIDRs to allow. Takes precedence over deny."`
+	ClientsToDeny  []string `usage:"Zero or more client IP addresses or CIDRs to deny. Ignored if any configured to allow"`
+
 	SimplifySRV bool `default:"false" usage:"Simplify fully qualified SRV records for mapping"`
 }
 
@@ -88,6 +91,7 @@ func main() {
 		if err != nil {
 			logrus.WithError(err).Fatal("trying to create cpu profile file")
 		}
+		//goland:noinspection GoUnhandledErrorResult
 		defer cpuProfileFile.Close()
 
 		logrus.WithField("file", config.CpuProfile).Info("Starting cpu profiling")
@@ -131,7 +135,12 @@ func main() {
 		trustedIpNets = append(trustedIpNets, ipNet)
 	}
 
-	connector := server.NewConnector(metricsBuilder.BuildConnectorMetrics(), config.UseProxyProtocol, config.ReceiveProxyProtocol, trustedIpNets)
+	clientFilter, err := server.NewClientFilter(config.ClientsToAllow, config.ClientsToDeny)
+	if err != nil {
+		logrus.WithError(err).Fatal("Unable to create client filter")
+	}
+
+	connector := server.NewConnector(metricsBuilder.BuildConnectorMetrics(), config.UseProxyProtocol, config.ReceiveProxyProtocol, trustedIpNets, clientFilter)
 	if config.NgrokToken != "" {
 		connector.UseNgrok(config.NgrokToken)
 	}