nixos/iperf: add openFirewall setting

Opens the specified tcp port.

nixos/modules/services/networking/iperf3.nix

@@ -19,6 +19,11 @@ let
       default     = null;
       description = "Bind to the specific interface associated with the given address.";
     };
+    openFirewall = mkOption {
+      type = types.bool;
+      default = false;
+      description = "Open ports in the firewall for iperf3.";
+    };
     verbose = mkOption {
       type        = types.bool;
       default     = false;
@@ -52,6 +57,11 @@ let
   };
 
   imp = {
+
+    networking.firewall = mkIf cfg.openFirewall {
+      allowedTCPPorts = [ cfg.port ];
+    };
+
     systemd.services.iperf3 = {
       description = "iperf3 daemon";
       unitConfig.Documentation = "man:iperf3(1) https://iperf.fr/iperf-doc.php";