fix(bridge): pick up MAC from another interface

This avoids the OPERSTATE unknown when the bridge is brought up but the
members are not ready yet.

This will make OPERSTATE to down, enabling us to wait until we have
brought up completely all the members.

Signed-off-by: Raito Bezarius <masterancpp@gmail.com>

modules/bridge/default.nix

@@ -28,6 +28,12 @@ in
         type = types.str;
         description = "bridge interface name to create";
       };
+
+      macAddressFromInterface = mkOption {
+        type = types.nullOr liminix.lib.types.service;
+        default = null;
+        description = "reuse mac address from an existing interface service";
+      };
     };
     members = config.system.callService ./members.nix {
       primary = mkOption {

modules/bridge/primary.nix

@@ -3,15 +3,20 @@
 , ifwait
 , lib
 }:
-{ ifname } :
+{ ifname, macAddressFromInterface ? null } :
 let
   inherit (liminix.services) bundle oneshot;
-  inherit (lib) mkOption types;
+  inherit (lib) mkOption types optional;
 in oneshot rec {
   name = "${ifname}.link";
   up = ''
-    ip link add name ${ifname} type bridge
+    ${if macAddressFromInterface == null then
+      "ip link add name ${ifname} type bridge"
+      else
+      "ip link add name ${ifname} address $(output ${macAddressFromInterface} ether) type bridge"}
     ${liminix.networking.ifup name ifname}
   '';
   down = "ip link set down dev ${ifname}";
+
+  dependencies = optional (macAddressFromInterface != null) macAddressFromInterface;
 }

pkgs/liminix-tools/networking/default.nix

@@ -9,6 +9,7 @@
     ip link set up dev ${ifname}
     (in_outputs ${name}
      echo ${ifname} > ifname
+     cat /sys/class/net/${ifname}/address > ether
     )
   '';
 }