nixos-config/config/domain-config/fudo.org/mail-server.nix

{ primaryMailserver, primaryDomain, authentikServer, servedDomains, ldapBase
, ldapBindDn, ldapBindPwFile, dkimRecord, saslDomain, authentikOutpostToken
, authentikVersion, ... }:

{ config, lib, pkgs, ... }:

with lib;
let
  inherit (pkgs.lib) getHostIpv4 getHostIpv6;
  hostname = config.instance.hostname;

in {
  config = {
    systemd.services.arion-mail-server = {
      requires = [ "podman.service" ];
      after = [ "podman.service" ];
    };

    # security.acme.certs = {
    #   "imap.${primaryDomain}".extraDomainNames = [ "mail.${primaryDomain}" ];
    #   "smtp.${primaryDomain}".extraDomainNames = [ "mail.${primaryDomain}" ];
    # };

    fudo = {
      zones = let
        mailserverIp = getHostIpv4 primaryMailserver;
        spfRecords = [
          ''@ IN TXT "v=spf1 mx ip4:${mailserverIp}/32 -all"''
          ''@ IN SPF "v=spf1 mx ip4:${mailserverIp}/32 -all"''
        ];
      in {
        "${primaryDomain}" = let
          mailserverDomain = config.fudo.hosts."${primaryMailserver}".domain;
          mailserverIps = {
            ipv4-address = getHostIpv4 primaryMailserver;
            ipv6-address = getHostIpv6 primaryMailserver;
          };
          srvRecord = host: port: [{ inherit host port; }];
        in {
          srv-records = {
            tcp = {
              imap = srvRecord "mail.${primaryDomain}" 143;
              imaps = srvRecord "mail.${primaryDomain}" 993;
              smtp = srvRecord "mail.${primaryDomain}" 25;
              submission = srvRecord "mail.${primaryDomain}" 587;
              submissions = srvRecord "mail.${primaryDomain}" 465;
            };
            udp = {
              smtp = srvRecord "mail.${primaryDomain}" 25;
              submission = srvRecord "mail.${primaryDomain}" 587;
            };
          };

          metric-records = genAttrs [ "dovecot" "postfix" "rspamd" ]
            (_: srvRecord "mail-stats.${primaryDomain}" 443);

          hosts = {
            imap = mailserverIps;
            smtp = mailserverIps;
            mail = mailserverIps;
            mail-stats = mailserverIps;
          };
          verbatim-dns-records = [ dkimRecord ] ++ spfRecords;
        };
      } // (genAttrs (filter (dom: dom != primaryDomain) servedDomains)
        (domain: { verbatim-dns-records = [ dkimRecord ] ++ spfRecords; }));

      metrics.prometheus.service-discovery-dns =
        (genAttrs [ "dovecot" "postfix" "rspamd" ]
          (metricType: [ "${metricType}._metrics._tcp.${primaryDomain}" ]));

      mail = {
        enable = hostname == primaryMailserver;
        debug = true;
        primary-domain = primaryDomain;
        extra-domains = servedDomains;
        sasl-domain = saslDomain;
        trusted-networks = config.instance.local-networks;
        smtp = {
          hostname = "mail.${primaryDomain}";
          spf.enable = false;
          ssl-directory =
            config.security.acme.certs."mail.${primaryDomain}".directory;
        };
        imap = {
          hostname = "mail.${primaryDomain}";
          ssl-directory =
            config.security.acme.certs."mail.${primaryDomain}".directory;
        };
        ldap = {
          authentik-host = "https://${authentikServer}";
          outpost-token = readFile authentikOutpostToken;
          base = ldapBase;
          bind-dn = ldapBindDn;
          bind-password-file = ldapBindPwFile;
        };
        images.ldap-proxy = "ghcr.io/goauthentik/ldap:${authentikVersion}";
        aliases = let admins = config.instance.local-admins;
        in {
          alias-users = {
            admin = admins;
            dmarc-reports = admins;
            ftp = admins;
            hostmaster = admins;
            irc = admins;
            postmaster = admins;
            root = admins;
            system = admins;
            webmaster = admins;
            www-data = admins;
          };
          user-aliases =
            let hasAliases = _: userOpts: userOpts.email-aliases != [ ];
            in mapAttrs (_: userOpts: userOpts.email-aliases)
            (filterAttrs hasAliases config.fudo.users);
        };
      };
    };

    services.nginx = mkIf (hostname == primaryMailserver) {
      enable = true;
      virtualHosts = {
        "imap.${primaryDomain}" = {
          enableACME = true;
          forceSSL = true;
          locations."/".return = "403 Forbidden";
        };
        "mail.${primaryDomain}" = {
          enableACME = true;
          forceSSL = true;
          locations."/".return = "301 https://webmail.${primaryDomain}";
        };
        "smtp.${primaryDomain}" = {
          enableACME = true;
          forceSSL = true;
          locations."/".return = "403 Forbidden";
        };
      };
    };
  };
}