infrastructure/modules/nixos/samba.nix

{
  config,
  lib,
  pkgs,
  ...
}: let
  inherit (lib.options) mkOption mkEnableOption;
  inherit (lib.modules) mkIf mkMerge mkBefore mkForce mkDefault mkOptionDefault;
  inherit (lib.attrsets) mapAttrs' mapAttrsToList nameValuePair;
  inherit (lib.strings) hasPrefix concatMapStringsSep;
  inherit (config.services) samba-wsdd;
  cfg = config.services.samba;
  settingValue = value:
    if builtins.isList value
    then concatMapStringsSep ", " settingValue value
    else if value == true
    then "yes"
    else if value == false
    then "no"
    else toString value;
in {
  options.services.samba = with lib.types; let
    settingPrimitive = oneOf [str int bool];
    settingType = oneOf [settingPrimitive (listOf settingPrimitive)];
  in {
    ldap = {
      enable = mkEnableOption "LDAP";
      passdb = {
        enable = mkEnableOption "LDAP authentication" // {
          default = true;
        };
        backend = mkOption {
          type = enum [ "ldapsam" "ipasam" ];
          default = "ldapsam";
        };
      };
      idmap = {
        enable = mkEnableOption "LDAP users" // {
          default = true;
        };
        domain = mkOption {
          type = str;
          default = "*";
        };
      };
      url = mkOption {
        type = str;
      };
      baseDn = mkOption {
        type = str;
      };
      adminDn = mkOption {
        type = nullOr str;
        default = "name=anonymous,${cfg.ldap.baseDn}";
      };
      adminPasswordPath = mkOption {
        type = nullOr path;
        default = null;
      };
    };
    kerberos = {
      enable = mkEnableOption "krb5";
      realm = mkOption {
        type = str;
      };
      keytabPath = mkOption {
        type = nullOr path;
        default = null;
      };
    };
    usershare = {
      enable = mkEnableOption "usershare";
      group = mkOption {
        type = str;
        default = "users";
      };
      path = mkOption {
        type = path;
        default = "/var/lib/samba/usershares";
      };
      templateShare = mkOption {
        type = str;
        default = "usershare-template";
      };
    };
    guest = {
      enable = mkEnableOption "guest account";
      user = mkOption {
        type = str;
        default = "nobody";
      };
    };
    idmap = let
      idmapModule = {
        config,
        name,
        ...
      }: {
        options = {
          backend = mkOption {
            type = str;
          };
          domain = mkOption {
            type = str;
            default = name;
          };
          range = {
            min = mkOption {
              type = int;
              default = 1000;
            };
            max = mkOption {
              type = int;
              default = 65534;
            };
          };
          readOnly = mkOption {
            type = bool;
            default = true;
          };
          settings = mkOption {
            type = attrsOf settingType;
            default = {};
          };
        };
        config = {
          settings = {
            backend = mkOptionDefault config.backend;
            "read only" = mkOptionDefault config.readOnly;
            range = mkOptionDefault "${toString config.range.min} - ${toString config.range.max}";
          };
        };
      };
    in {
      domains = mkOption {
        type = attrsOf (submodule idmapModule);
        default = {
          nss = {
            backend = "nss";
            domain = "*";
          };
        };
      };
    };
    passdb.smbpasswd.path = mkOption {
      type = nullOr path;
      default = null;
    };
    settings = mkOption {
      type = attrsOf settingType;
      default = {};
    };
  };

  config = {
    services.samba = {
      package = mkIf cfg.ldap.enable (mkDefault (
        if cfg.ldap.passdb.enable && cfg.ldap.passdb.backend == "ipasam" then pkgs.samba-ipa else pkgs.samba-ldap
      ));
      ldap = {
        adminPasswordPath = mkIf (cfg.ldap.adminDn != null && hasPrefix "name=anonymous," cfg.ldap.adminDn) (mkDefault (
          pkgs.writeText "smb-ldap-anonymous" "anonymous"
        ));
      };
      idmap.domains = mkMerge [
        (mkIf (cfg.ldap.enable && cfg.ldap.idmap.enable) {
          ldap = {
            backend = mkOptionDefault "ldap";
            domain = mkDefault cfg.ldap.idmap.domain;
            settings = {
              ldap_url = mkOptionDefault cfg.ldap.url;
            };
          };
        })
      ];
      settings = mkMerge ([
        {
          "use sendfile" = mkOptionDefault true;
        }
        (mkIf (cfg.passdb.smbpasswd.path != null) {
          "passdb backend" = mkOptionDefault "smbpasswd:${cfg.passdb.smbpasswd.path}";
        })
        (mkIf cfg.ldap.enable {
          "ldap ssl" = mkIf (hasPrefix "ldaps://" cfg.ldap.url) (mkOptionDefault "off");
          "ldap admin dn" = mkIf (cfg.ldap.adminDn != null) (mkOptionDefault cfg.ldap.adminDn);
          "ldap suffix" = mkOptionDefault cfg.ldap.baseDn;
        })
        (mkIf cfg.kerberos.enable {
          "realm" = mkOptionDefault cfg.kerberos.realm;
          "kerberos method" = mkOptionDefault (
            if cfg.kerberos.keytabPath != null then "dedicated keytab"
            else "system keytab"
          );
          "dedicated keytab file" = mkIf (cfg.kerberos.keytabPath != null) (mkOptionDefault
            "FILE:${cfg.kerberos.keytabPath}"
          );
          "create krb5 conf" = mkOptionDefault false;
        })
        (mkIf cfg.usershare.enable {
          "usershare allow guests" = mkOptionDefault true;
          "usershare max shares" = mkOptionDefault 16;
          "usershare owner only" = mkOptionDefault true;
          "usershare template share" = mkOptionDefault cfg.usershare.templateShare;
          "usershare path" = mkOptionDefault cfg.usershare.path;
          "usershare prefix allow list" = mkOptionDefault [ cfg.usershare.path ];
        })
        (mkIf cfg.guest.enable {
          "map to guest" = mkOptionDefault "Bad User";
          "guest account" = mkOptionDefault cfg.guest.user;
        })
      ] ++ mapAttrsToList (_: idmap: mapAttrs' (key: value: nameValuePair "idmap config ${idmap.domain} : ${key}" (mkOptionDefault value)) idmap.settings) cfg.idmap.domains);
      extraConfig = mkMerge (
        mapAttrsToList (key: value: ''${key} = ${settingValue value}'') cfg.settings
        ++ [
          (mkIf (cfg.ldap.enable && cfg.ldap.passdb.enable) (mkBefore ''
            passdb backend = ${cfg.ldap.passdb.backend}:"${cfg.ldap.url}"
          ''))
        ]
      );
      shares.${cfg.usershare.templateShare} = mkIf cfg.usershare.enable {
        "-valid" = false;
      };
    };

    systemd.services.samba-smbd = mkIf cfg.enable {
      serviceConfig = let
        ldap-pass = pkgs.writeShellScript "samba-ldap-pass" ''
          ${cfg.package}/bin/smbpasswd -c /etc/samba/smb.conf -w $(cat ${cfg.ldap.adminPasswordPath})
        '';
      in {
        ExecStartPre = mkMerge [
          (mkIf (cfg.ldap.enable && cfg.ldap.adminPasswordPath != null) [
            "${ldap-pass}"
          ])
        ];
      };
    };

    systemd.tmpfiles.rules = mkIf (cfg.enable && cfg.usershare.enable) [
      "d ${cfg.usershare.path} 1770 root ${cfg.usershare.group}"
    ];

    networking.firewall.interfaces.local = {
      allowedTCPPorts = mkMerge [
        (mkIf (cfg.enable && !cfg.openFirewall) [139 445])
        (mkIf (samba-wsdd.enable && !samba-wsdd.openFirewall) [5357])
      ];
      allowedUDPPorts = mkMerge [
        (mkIf (cfg.enable && !cfg.openFirewall) [137 138])
        (mkIf (samba-wsdd.enable && !samba-wsdd.openFirewall) [3702])
      ];
    };
  };
}