add rmilter and certificate files

mail-server/rmilter.nix

@@ -0,0 +1,55 @@
+#  nixos-mailserver: a simple mail server
+#  Copyright (C) 2016-2017  Robin Raymond
+#
+#  This program is free software: you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation, either version 3 of the License, or
+#  (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program. If not, see <http://www.gnu.org/licenses/>
+
+{ domain, virus_scanning, dkim_signing }:
+
+let
+  clamav = if virus_scanning
+           then
+           ''
+             clamav {
+               servers = /var/run/clamav/clam.ctl;
+             };
+           ''
+           else "";
+  dkim = if dkim_signing
+         then
+         ''
+            dkim {
+              domain {
+                key = /etc/nixos/dkim/${domain}.pem;
+                domain = "${domain}";
+                selector = "dkim";
+              };
+              sign_alg = sha256;
+              auth_only = yes;
+            }
+         ''
+         else "";
+in
+{
+  enable = true;
+  # debug = true;
+  postfix.enable = true;
+  rspamd.enable = true;
+  extraConfig =
+  ''
+    ${clamav}
+
+    ${dkim}
+  '';
+}
+