{ config, pkgs, lib, ... }: with lib; { options = { services.xl2tpd = { enable = mkEnableOption "xl2tpd, the Layer 2 Tunnelling Protocol Daemon"; serverIp = mkOption { type = types.str; description = "The server-side IP address."; default = "10.125.125.1"; }; clientIpRange = mkOption { type = types.str; description = "The range from which client IPs are drawn."; default = "10.125.125.2-11"; }; extraXl2tpOptions = mkOption { type = types.lines; description = "Adds extra lines to the xl2tpd configuration file."; default = ""; }; extraPppdOptions = mkOption { type = types.lines; description = "Adds extra lines to the pppd options file."; default = ""; example = '' ms-dns 8.8.8.8 ms-dns 8.8.4.4 ''; }; }; }; config = mkIf config.services.xl2tpd.enable { systemd.services.xl2tpd = let cfg = config.services.xl2tpd; # Config files from https://help.ubuntu.com/community/L2TPServer xl2tpd-conf = pkgs.writeText "xl2tpd.conf" '' [global] ipsec saref = no [lns default] local ip = ${cfg.serverIp} ip range = ${cfg.clientIpRange} pppoptfile = ${pppd-options} length bit = yes ; Extra ${cfg.extraXl2tpOptions} ''; pppd-options = pkgs.writeText "ppp-options-xl2tpd.conf" '' refuse-pap refuse-chap refuse-mschap require-mschap-v2 # require-mppe-128 asyncmap 0 auth crtscts idle 1800 mtu 1200 mru 1200 lock hide-password local # debug name xl2tpd # proxyarp lcp-echo-interval 30 lcp-echo-failure 4 # Extra: ${cfg.extraPppdOptions} ''; xl2tpd-ppp-wrapped = pkgs.stdenv.mkDerivation { name = "xl2tpd-ppp-wrapped"; phases = [ "installPhase" ]; nativeBuildInputs = with pkgs; [ makeWrapper ]; installPhase = '' mkdir -p $out/bin makeWrapper ${pkgs.ppp}/sbin/pppd $out/bin/pppd \ --set LD_PRELOAD "${pkgs.libredirect}/lib/libredirect.so" \ --set NIX_REDIRECTS "/etc/ppp=/etc/xl2tpd/ppp" makeWrapper ${pkgs.xl2tpd}/bin/xl2tpd $out/bin/xl2tpd \ --set LD_PRELOAD "${pkgs.libredirect}/lib/libredirect.so" \ --set NIX_REDIRECTS "${pkgs.ppp}/sbin/pppd=$out/bin/pppd" ''; }; in { description = "xl2tpd server"; requires = [ "network-online.target" ]; wantedBy = [ "multi-user.target" ]; preStart = '' mkdir -p -m 700 /etc/xl2tpd pushd /etc/xl2tpd > /dev/null mkdir -p -m 700 ppp [ -f ppp/chap-secrets ] || cat > ppp/chap-secrets << EOF # Secrets for authentication using CHAP # client server secret IP addresses #username xl2tpd password * EOF chown root:root ppp/chap-secrets chmod 600 ppp/chap-secrets # The documentation says this file should be present but doesn't explain why and things work even if not there: [ -f l2tp-secrets ] || (echo -n "* * "; ${pkgs.apg}/bin/apg -n 1 -m 32 -x 32 -a 1 -M LCN) > l2tp-secrets chown root:root l2tp-secrets chmod 600 l2tp-secrets popd > /dev/null mkdir -p /run/xl2tpd chown root:root /run/xl2tpd chmod 700 /run/xl2tpd ''; serviceConfig = { ExecStart = "${xl2tpd-ppp-wrapped}/bin/xl2tpd -D -c ${xl2tpd-conf} -s /etc/xl2tpd/l2tp-secrets -p /run/xl2tpd/pid -C /run/xl2tpd/control"; KillMode = "process"; Restart = "on-success"; Type = "simple"; PIDFile = "/run/xl2tpd/pid"; }; }; }; }