nixos-config/modules/mailserver/rspamd.nix

# SPDX-FileCopyrightText: 2023 Simon Bruder <simon@sbruder.de>
#
# SPDX-License-Identifier: AGPL-3.0-or-later

{ config, lib, ... }:
let
  cfg = config.sbruder.mailserver;
in
{
  options.sbruder.mailserver.spam = {
    enable = (lib.mkEnableOption "spam filtering") // { default = true; };
  };

  config = lib.mkIf (cfg.enable && cfg.spam.enable) {
    sops.secrets.rspamd-worker-controller = {
      owner = config.users.users.rspamd.name;
      sopsFile = ../../machines + "/${config.networking.hostName}/secrets.yaml";
    };

    services.rspamd = {
      enable = true;
      postfix.enable = true;
      workers = {
        normal = {
          includes = [ "$CONFDIR/worker-normal.inc" ];
          bindSockets = lib.singleton {
            socket = "/run/rspamd/rspamd.sock";
            mode = "0660";
            owner = "${config.services.rspamd.user}";
            group = "${config.services.rspamd.group}";
          };
        };
        controller = {
          includes = [ "$CONFDIR/worker-controller.inc" ];
          bindSockets = [ "127.0.0.1:11334" ] ++ lib.optional config.sbruder.wireguard.home.enable "${config.sbruder.wireguard.home.address}:11334";
        };
      };
      locals = {
        "dkim_signing.conf".text = ''
          enabled = false;
        '';
        "logging.inc".text = ''
          # starts at info, drops to notice once started up
          level = "silent";
        '';
        "milter_headers.conf".text = ''
          extended_spam_headers = true;
        '';
        "multimap.conf".text = ''
          SENDER_BLOCKED {
            type = "from";
            filter = "email:addr";
            map = "/var/lib/rspamd/blocked_senders.map";
            symbol = "SENDER_BLOCKED";
            description = "Sender’s address is manually blocked";
            prefilter = true;
            action = "reject";
            score = 30.0;
          }
          SENDER_DOMAIN_BLOCKED {
            type = "from";
            filter = "email:domain:tld";
            map = "/var/lib/rspamd/blocked_sender_domains.map";
            symbol = "SENDER_DOMAIN_BLOCKED";
            description = "Sender’s effective second level domain is manually blocked";
            score = 8.0;
          }
        '';
        "redis.conf".text = ''
          servers = "127.0.0.1:${toString config.services.redis.servers.rspamd.port}"
        '';
        "worker-controller.inc".source = config.sops.secrets.rspamd-worker-controller.path; # includes password
      };
    };

    services.redis = {
      vmOverCommit = true;
      servers.rspamd = {
        enable = true;
        port = 6379;
      };
    };
  };
}