bucur/modules/services/tailscale.nix

{ pkgs, ... }:
{
  services.tailscale.enable = true;
  services.tailscale.port = 41641;
  services.tailscale.useRoutingFeatures = "server";
  services.tailscale.extraUpFlags = [
    "--ssh"
    "--advertise-exit-node"
    "--hostname=bucur"
  ];

  environment.systemPackages = [ pkgs.ethtool ];

  systemd.services.tailscale-offload-tune = {
    description = "Disable GRO forwarding for Tailscale exit node performance";
    after = [ "network-online.target" ];
    wants = [ "network-online.target" ];
    serviceConfig = {
      Type = "oneshot";
      ExecStart = ''
        /bin/sh -c 'DEV="$(${pkgs.iproute2}/bin/ip -o route get 8.8.8.8 2>/dev/null | ${pkgs.gawk}/bin/awk "{for (i=1;i<=NF;i++) if (\\$i==\\\"dev\\\") {print \\$(i+1); exit}}")"; if [ -n "$DEV" ]; then ${pkgs.ethtool}/bin/ethtool -K "$DEV" rx-udp-gro-forwarding on rx-gro-list off || true; fi'
      '';
    };
    wantedBy = [ "multi-user.target" ];
  };
}