{ config, lib, pkgs, ... }: with lib; let cfg = config.services.dkimproxy-out; keydir = "/var/lib/dkimproxy-out"; privkey = "${keydir}/private.key"; pubkey = "${keydir}/public.key"; in { ##### interface options = { services.dkimproxy-out = { enable = mkOption { type = types.bool; default = false; description = '' Whether to enable dkimproxy_out. Note that a key will be auto-generated, and can be found in ${keydir}. ''; }; listen = mkOption { type = types.str; example = "127.0.0.1:10027"; description = "Address:port DKIMproxy should listen on."; }; relay = mkOption { type = types.str; example = "127.0.0.1:10028"; description = "Address:port DKIMproxy should forward mail to."; }; domains = mkOption { type = with types; listOf str; example = [ "example.org" "example.com" ]; description = "List of domains DKIMproxy can sign for."; }; selector = mkOption { type = types.str; example = "selector1"; description = '' The selector to use for DKIM key identification. For example, if 'selector1' is used here, then for each domain 'example.org' given in `domain`, 'selector1._domainkey.example.org' should contain the TXT record indicating the public key is the one in ${pubkey}: "v=DKIM1; t=s; p=[THE PUBLIC KEY]". ''; }; keySize = mkOption { type = types.int; default = 2048; description = '' Size of the RSA key to use to sign outgoing emails. Note that the maximum mandatorily verified as per RFC6376 is 2048. ''; }; # TODO: allow signature for other schemes than dkim(c=relaxed/relaxed)? # This being the scheme used by gmail, maybe nothing more is needed for # reasonable use. }; }; ##### implementation config = let configfile = pkgs.writeText "dkimproxy_out.conf" '' listen ${cfg.listen} relay ${cfg.relay} domain ${concatStringsSep "," cfg.domains} selector ${cfg.selector} signature dkim(c=relaxed/relaxed) keyfile ${privkey} ''; in mkIf cfg.enable { users.groups.dkimproxy-out = {}; users.users.dkimproxy-out = { description = "DKIMproxy_out daemon"; group = "dkimproxy-out"; isSystemUser = true; }; systemd.services.dkimproxy-out = { description = "DKIMproxy_out"; wantedBy = [ "multi-user.target" ]; preStart = '' if [ ! -d "${keydir}" ]; then mkdir -p "${keydir}" chmod 0700 "${keydir}" ${pkgs.openssl}/bin/openssl genrsa -out "${privkey}" ${toString cfg.keySize} ${pkgs.openssl}/bin/openssl rsa -in "${privkey}" -pubout -out "${pubkey}" chown -R dkimproxy-out:dkimproxy-out "${keydir}" fi ''; script = '' exec ${pkgs.dkimproxy}/bin/dkimproxy.out --conf_file=${configfile} ''; serviceConfig = { User = "dkimproxy-out"; PermissionsStartOnly = true; }; }; }; }