{ config, lib, pkgs, ... }: with lib; let cfg = config.services.libreswan; libexec = "${pkgs.libreswan}/libexec/ipsec"; ipsec = "${pkgs.libreswan}/sbin/ipsec"; trim = chars: str: let nonchars = filter (x : !(elem x.value chars)) (imap0 (i: v: {ind = i; value = v;}) (stringToCharacters str)); in if length nonchars == 0 then "" else substring (head nonchars).ind (add 1 (sub (last nonchars).ind (head nonchars).ind)) str; indent = str: concatStrings (concatMap (s: [" " (trim [" " "\t"] s) "\n"]) (splitString "\n" str)); configText = indent (toString cfg.configSetup); connectionText = concatStrings (mapAttrsToList (n: v: '' conn ${n} ${indent v} '') cfg.connections); configFile = pkgs.writeText "ipsec-nixos.conf" '' config setup ${configText} ${connectionText} ''; policyFiles = mapAttrs' (name: text: { name = "ipsec.d/policies/${name}"; value.source = pkgs.writeText "ipsec-policy-${name}" text; }) cfg.policies; in { ###### interface options = { services.libreswan = { enable = mkEnableOption (lib.mdDoc "Libreswan IPsec service"); configSetup = mkOption { type = types.lines; default = '' protostack=netkey virtual_private=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%v4:172.16.0.0/12,%v4:25.0.0.0/8,%v4:100.64.0.0/10,%v6:fd00::/8,%v6:fe80::/10 ''; example = '' secretsfile=/root/ipsec.secrets protostack=netkey virtual_private=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%v4:172.16.0.0/12,%v4:25.0.0.0/8,%v4:100.64.0.0/10,%v6:fd00::/8,%v6:fe80::/10 ''; description = lib.mdDoc "Options to go in the 'config setup' section of the Libreswan IPsec configuration"; }; connections = mkOption { type = types.attrsOf types.lines; default = {}; example = literalExpression '' { myconnection = ''' auto=add left=%defaultroute leftid=@user right=my.vpn.com ikev2=no ikelifetime=8h '''; } ''; description = lib.mdDoc "A set of connections to define for the Libreswan IPsec service"; }; policies = mkOption { type = types.attrsOf types.lines; default = {}; example = literalExpression '' { private-or-clear = ''' # Attempt opportunistic IPsec for the entire Internet 0.0.0.0/0 ::/0 '''; } ''; description = lib.mdDoc '' A set of policies to apply to the IPsec connections. ::: {.note} The policy name must match the one of connection it needs to apply to. ::: ''; }; disableRedirects = mkOption { type = types.bool; default = true; description = lib.mdDoc '' Whether to disable send and accept redirects for all network interfaces. See the Libreswan [ FAQ](https://libreswan.org/wiki/FAQ#Why_is_it_recommended_to_disable_send_redirects_in_.2Fproc.2Fsys.2Fnet_.3F) page for why this is recommended. ''; }; }; }; ###### implementation config = mkIf cfg.enable { # Install package, systemd units, etc. environment.systemPackages = [ pkgs.libreswan pkgs.iproute2 ]; systemd.packages = [ pkgs.libreswan ]; systemd.tmpfiles.packages = [ pkgs.libreswan ]; # Install configuration files environment.etc = { "ipsec.secrets".source = "${pkgs.libreswan}/etc/ipsec.secrets"; "ipsec.conf".source = "${pkgs.libreswan}/etc/ipsec.conf"; "ipsec.d/01-nixos.conf".source = configFile; } // policyFiles; # Create NSS database directory systemd.tmpfiles.rules = [ "d /var/lib/ipsec/nss 755 root root -" ]; systemd.services.ipsec = { description = "Internet Key Exchange (IKE) Protocol Daemon for IPsec"; wantedBy = [ "multi-user.target" ]; restartTriggers = [ configFile ] ++ mapAttrsToList (n: v: v.source) policyFiles; path = with pkgs; [ libreswan iproute2 procps nssTools iptables nettools ]; preStart = optionalString cfg.disableRedirects '' # Disable send/receive redirects echo 0 | tee /proc/sys/net/ipv4/conf/*/send_redirects echo 0 | tee /proc/sys/net/ipv{4,6}/conf/*/accept_redirects ''; }; }; }