Merge pull request #270467 from nalves599/269944-keepalived-firewall

nixos/keepalived: add openFirewall option

nixos/modules/services/networking/keepalived/default.nix

···
         '';
       };
 
+      openFirewall = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc ''
+          Whether to automatically allow VRRP and AH packets in the firewall.
+        '';
+      };
+
       enableScriptSecurity = mkOption {
         type = types.bool;
         default = false;
···
   config = mkIf cfg.enable {
 
     assertions = flatten (map vrrpInstanceAssertions vrrpInstances);
+
+    networking.firewall = lib.mkIf cfg.openFirewall {
+      extraCommands = ''
+        # Allow VRRP and AH packets
+        ip46tables -A nixos-fw -p vrrp -m comment --comment "services.keepalived.openFirewall" -j ACCEPT
+        ip46tables -A nixos-fw -p ah -m comment --comment "services.keepalived.openFirewall" -j ACCEPT
+      '';
+
+      extraStopCommands = ''
+        ip46tables -D nixos-fw -p vrrp -m comment --comment "services.keepalived.openFirewall" -j ACCEPT
+        ip46tables -D nixos-fw -p ah -m comment --comment "services.keepalived.openFirewall" -j ACCEPT
+      '';
+    };
 
     systemd.timers.keepalived-boot-delay = {
       description = "Keepalive Daemon delay to avoid instant transition to MASTER state";