path: root/hosts/lia/modules/sshfwd.nix

{ pkgs, config, ... }: let
  mkFwdSrv = {
    local_port,
    remote_port,
    remote_user,
    remote ? "sinanmohd.com",
    ssh_port ? 22,
    key ? config.sops.secrets."sshfwd/${remote}".path,
  }: {
    "sshfwd-${toString local_port}-${remote}:${toString remote_port}" = {
      description = "Forwarding port ${toString local_port} to ${remote}";

      wantedBy = [ "multi-user.target" ];
      after = [ "network-online.target" ];
      wants = [ "network-online.target" ];
      # restart rather than stop+start this unit to prevent
      # the ssh from dying during switch-to-configuration.
      stopIfChanged = false;

      path = [ pkgs.openssh ];
      script = ''
        echo -n "Forwarding port ${toString local_port}"
        exec ssh -N ${remote_user}@${remote} -p ${toString ssh_port} \
            -R '[::]:${toString remote_port}:127.0.0.1:${toString local_port}' \
            -i ${key}
      '';
    };
  };
in {
  sops.secrets."sshfwd/sinanmohd.com" = {};
  sops.secrets."sshfwd/lia.sinanmohd.com" = {};

  environment.systemPackages = with pkgs; [ openssh ];
  systemd.services
    = (mkFwdSrv {
        local_port = 22;
        remote_user = "lia";
        remote_port = 2222;
      }) //
      (mkFwdSrv {
        local_port = 22;
        remote_port = 22;
        ssh_port = 23;
        remote_user = "root";
        remote = "lia.sinanmohd.com";
      });
}