NixOS-Config/modules/system/devices/networking/firewall/default.nix

{ lib, config, ... }:
{
  options.system.firewall = {
    server = {
      enable = lib.mkOption {    
        type = lib.types.bool;     
        default = false;       
        description = "Enable server firewall settings";
      };
    };
  };

  config = {
    networking = {
      firewall = {
        allowPing = false;
        extraInputRules = ''
          ${lib.optionalString (!config.system.firewall.server.enable) ''
            ip saddr { ${config.ips.server}, 10.100.0.1 } accept comment "Accept Server"
          ''}
          ${lib.optionalString config.system.firewall.server.enable ''
            ip saddr { ${config.ips.localSpan}.0/24, 10.100.0.0/24 } tcp dport 2049 accept comment "Accept NFS"
            ip saddr { ${config.ips.pc}, ${config.secrets.lunaIP}, ${config.secrets.cornIP} } tcp dport { 1935, 1945 } accept comment "Accept RTMP"
          ''}
        '';
      };

      # Nftables configuration only if server is enabled
      nftables = lib.mkIf config.system.firewall.server.enable {
        tables = {
          forwarding = {
            family = "ip";
            content = ''
              chain PREROUTING {
                type nat hook prerouting priority dstnat; policy accept;
                tcp dport 2211 dnat to ${config.ips.pc}:22 comment "SSH to PC"
                tcp dport 2222 dnat to 10.100.0.19:22 comment "SSH to Oracle VM"
                
                udp dport { 27005, 27015, 7777 } dnat to ${config.ips.pc} comment "PC Hosted Games"
                
                tcp dport { 58010, 57989, 57984 } dnat to ${config.ips.pc} comment "PC Sunshine TCP"
                udp dport { 57998, 57999, 58000 } dnat to ${config.ips.pc} comment "PC Sunshine UDP"
                
                tcp dport { 38010, 37989, 37984 } dnat to ${config.ips.vm} comment "VM Sunshine TCP"
                udp dport { 37998, 37999, 38000 } dnat to ${config.ips.vm} comment "VM Sunshine UDP"
                
                udp dport { 7790, 7791, 7792 } dnat to ${config.ips.hx} comment "Deus Ex"
                
                ip saddr ${config.secrets.cornIP} tcp dport { 9943, 9944 } dnat to ${config.ips.vm} comment "VM ALVR TCP"
                ip saddr ${config.secrets.cornIP} udp dport { 9943, 9944 } dnat to ${config.ips.vm} comment "VM ALVR UDP"
              }

              chain POSTROUTING {
                type nat hook postrouting priority 100; policy accept;
                oifname "${config.ips.netInt}" masquerade
              }
            '';
          };
        };
      };
    };

    # Enable IP forwarding for the server configuration
    boot.kernel.sysctl."net.ipv4.ip_forward" = lib.mkIf config.system.firewall.server.enable 1;
  };
}