1 files changed, 369 insertions, 0 deletions

diff --git a/modules/coturn.nix b/modules/coturn.nix
new file mode 100644
index 00000000..faa4b5a2
--- /dev/null
+++ b/modules/coturn.nix
@@ -0,0 +1,369 @@
+{ config, lib, pkgs, ... }:
+with lib;
+let
+  cfg = config.services.coturn;
+  pidfile = "/run/turnserver/turnserver.pid";
+  configFile = pkgs.writeText "turnserver.conf" ''
+listening-port=${toString cfg.listening-port}
+tls-listening-port=${toString cfg.tls-listening-port}
+alt-listening-port=${toString cfg.alt-listening-port}
+alt-tls-listening-port=${toString cfg.alt-tls-listening-port}
+${concatStringsSep "\n" (map (x: "listening-ip=${x}") cfg.listening-ips)}
+${concatStringsSep "\n" (map (x: "relay-ip=${x}") cfg.relay-ips)}
+min-port=${toString cfg.min-port}
+max-port=${toString cfg.max-port}
+${lib.optionalString cfg.lt-cred-mech "lt-cred-mech"}
+${lib.optionalString cfg.no-auth "no-auth"}
+${lib.optionalString cfg.use-auth-secret "use-auth-secret"}
+${lib.optionalString (cfg.static-auth-secret != null) ("static-auth-secret=${cfg.static-auth-secret}")}
+${lib.optionalString (cfg.static-auth-secret-file != null) ("static-auth-secret=#static-auth-secret#")}
+realm=${cfg.realm}
+${lib.optionalString cfg.no-udp "no-udp"}
+${lib.optionalString cfg.no-tcp "no-tcp"}
+${lib.optionalString cfg.no-tls "no-tls"}
+${lib.optionalString cfg.no-dtls "no-dtls"}
+${lib.optionalString cfg.no-udp-relay "no-udp-relay"}
+${lib.optionalString cfg.no-tcp-relay "no-tcp-relay"}
+${lib.optionalString (cfg.cert != null) "cert=${cfg.cert}"}
+${lib.optionalString (cfg.pkey != null) "pkey=${cfg.pkey}"}
+${lib.optionalString (cfg.dh-file != null) ("dh-file=${cfg.dh-file}")}
+no-stdout-log
+syslog
+pidfile=${pidfile}
+${lib.optionalString cfg.secure-stun "secure-stun"}
+${lib.optionalString cfg.no-cli "no-cli"}
+cli-ip=${cfg.cli-ip}
+cli-port=${toString cfg.cli-port}
+${lib.optionalString (cfg.cli-password != null) ("cli-password=${cfg.cli-password}")}
+${cfg.extraConfig}
+'';
+in {
+  disabledModules = [ "services/networking/coturn.nix" ];
+
+  options = {
+    services.coturn = {
+      enable = mkEnableOption (lib.mdDoc "coturn TURN server");
+      listening-port = mkOption {
+        type = types.int;
+        default = 3478;
+        description = lib.mdDoc ''
+          TURN listener port for UDP and TCP.
+          Note: actually, TLS and DTLS sessions can connect to the
+          "plain" TCP and UDP port(s), too - if allowed by configuration.
+        '';
+      };
+      tls-listening-port = mkOption {
+        type = types.int;
+        default = 5349;
+        description = lib.mdDoc ''
+          TURN listener port for TLS.
+          Note: actually, "plain" TCP and UDP sessions can connect to the TLS and
+          DTLS port(s), too - if allowed by configuration. The TURN server
+          "automatically" recognizes the type of traffic. Actually, two listening
+          endpoints (the "plain" one and the "tls" one) are equivalent in terms of
+          functionality; but we keep both endpoints to satisfy the RFC 5766 specs.
+          For secure TCP connections, we currently support SSL version 3 and
+          TLS version 1.0, 1.1 and 1.2.
+          For secure UDP connections, we support DTLS version 1.
+        '';
+      };
+      alt-listening-port = mkOption {
+        type = types.int;
+        default = cfg.listening-port + 1;
+        defaultText = literalExpression "listening-port + 1";
+        description = lib.mdDoc ''
+          Alternative listening port for UDP and TCP listeners;
+          default (or zero) value means "listening port plus one".
+          This is needed for RFC 5780 support
+          (STUN extension specs, NAT behavior discovery). The TURN Server
+          supports RFC 5780 only if it is started with more than one
+          listening IP address of the same family (IPv4 or IPv6).
+          RFC 5780 is supported only by UDP protocol, other protocols
+          are listening to that endpoint only for "symmetry".
+        '';
+      };
+      alt-tls-listening-port = mkOption {
+        type = types.int;
+        default = cfg.tls-listening-port + 1;
+        defaultText = literalExpression "tls-listening-port + 1";
+        description = lib.mdDoc ''
+          Alternative listening port for TLS and DTLS protocols.
+        '';
+      };
+      listening-ips = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        example = [ "203.0.113.42" "2001:DB8::42" ];
+        description = lib.mdDoc ''
+          Listener IP addresses of relay server.
+          If no IP(s) specified in the config file or in the command line options,
+          then all IPv4 and IPv6 system IPs will be used for listening.
+        '';
+      };
+      relay-ips = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        example = [ "203.0.113.42" "2001:DB8::42" ];
+        description = lib.mdDoc ''
+          Relay address (the local IP address that will be used to relay the
+          packets to the peer).
+          Multiple relay addresses may be used.
+          The same IP(s) can be used as both listening IP(s) and relay IP(s).
+
+          If no relay IP(s) specified, then the turnserver will apply the default
+          policy: it will decide itself which relay addresses to be used, and it
+          will always be using the client socket IP address as the relay IP address
+          of the TURN session (if the requested relay address family is the same
+          as the family of the client socket).
+        '';
+      };
+      min-port = mkOption {
+        type = types.int;
+        default = 49152;
+        description = lib.mdDoc ''
+          Lower bound of UDP relay endpoints
+        '';
+      };
+      max-port = mkOption {
+        type = types.int;
+        default = 65535;
+        description = lib.mdDoc ''
+          Upper bound of UDP relay endpoints
+        '';
+      };
+      lt-cred-mech = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc ''
+          Use long-term credential mechanism.
+        '';
+      };
+      no-auth = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc ''
+          This option is opposite to lt-cred-mech.
+          (TURN Server with no-auth option allows anonymous access).
+          If neither option is defined, and no users are defined,
+          then no-auth is default. If at least one user is defined,
+          in this file or in command line or in usersdb file, then
+          lt-cred-mech is default.
+        '';
+      };
+      use-auth-secret = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc ''
+          TURN REST API flag.
+          Flag that sets a special authorization option that is based upon authentication secret.
+          This feature can be used with the long-term authentication mechanism, only.
+          This feature purpose is to support "TURN Server REST API", see
+          "TURN REST API" link in the project's page
+          https://github.com/coturn/coturn/
+
+          This option is used with timestamp:
+
+          usercombo -> "timestamp:userid"
+          turn user -> usercombo
+          turn password -> base64(hmac(secret key, usercombo))
+
+          This allows TURN credentials to be accounted for a specific user id.
+          If you don't have a suitable id, the timestamp alone can be used.
+          This option is just turning on secret-based authentication.
+          The actual value of the secret is defined either by option static-auth-secret,
+          or can be found in the turn_secret table in the database.
+        '';
+      };
+      static-auth-secret = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = lib.mdDoc ''
+          'Static' authentication secret value (a string) for TURN REST API only.
+          If not set, then the turn server
+          will try to use the 'dynamic' value in turn_secret table
+          in user database (if present). The database-stored  value can be changed on-the-fly
+          by a separate program, so this is why that other mode is 'dynamic'.
+        '';
+      };
+      static-auth-secret-file = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = lib.mdDoc ''
+          Path to the file containing the static authentication secret.
+        '';
+      };
+      realm = mkOption {
+        type = types.str;
+        default = config.networking.hostName;
+        defaultText = literalExpression "config.networking.hostName";
+        example = "example.com";
+        description = lib.mdDoc ''
+          The default realm to be used for the users when no explicit
+          origin/realm relationship was found in the database, or if the TURN
+          server is not using any database (just the commands-line settings
+          and the userdb file). Must be used with long-term credentials
+          mechanism or with TURN REST API.
+        '';
+      };
+      cert = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        example = "/var/lib/acme/example.com/fullchain.pem";
+        description = lib.mdDoc ''
+          Certificate file in PEM format.
+        '';
+      };
+      pkey = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        example = "/var/lib/acme/example.com/key.pem";
+        description = lib.mdDoc ''
+          Private key file in PEM format.
+        '';
+      };
+      dh-file = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = lib.mdDoc ''
+          Use custom DH TLS key, stored in PEM format in the file.
+        '';
+      };
+      secure-stun = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc ''
+          Require authentication of the STUN Binding request.
+          By default, the clients are allowed anonymous access to the STUN Binding functionality.
+        '';
+      };
+      no-cli = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc ''
+          Turn OFF the CLI support.
+        '';
+      };
+      cli-ip = mkOption {
+        type = types.str;
+        default = "127.0.0.1";
+        description = lib.mdDoc ''
+          Local system IP address to be used for CLI server endpoint.
+        '';
+      };
+      cli-port = mkOption {
+        type = types.int;
+        default = 5766;
+        description = lib.mdDoc ''
+          CLI server port.
+        '';
+      };
+      cli-password = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = lib.mdDoc ''
+          CLI access password.
+          For the security reasons, it is recommended to use the encrypted
+          for of the password (see the -P command in the turnadmin utility).
+        '';
+      };
+      no-udp = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc "Disable UDP client listener";
+      };
+      no-tcp = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc "Disable TCP client listener";
+      };
+      no-tls = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc "Disable TLS client listener";
+      };
+      no-dtls = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc "Disable DTLS client listener";
+      };
+      no-udp-relay = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc "Disable UDP relay endpoints";
+      };
+      no-tcp-relay = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc "Disable TCP relay endpoints";
+      };
+      extraConfig = mkOption {
+        type = types.lines;
+        default = "";
+        description = lib.mdDoc "Additional configuration options";
+      };
+    };
+  };
+
+  config = mkIf cfg.enable (mkMerge ([
+    { assertions = [
+      { assertion = cfg.static-auth-secret != null -> cfg.static-auth-secret-file == null ;
+        message = "static-auth-secret and static-auth-secret-file cannot be set at the same time";
+      }
+    ];}
+
+    {
+      users.users.turnserver =
+        { uid = config.ids.uids.turnserver;
+          group = "turnserver";
+          description = "coturn TURN server user";
+        };
+      users.groups.turnserver =
+        { gid = config.ids.gids.turnserver;
+          members = [ "turnserver" ];
+        };
+
+      systemd.services.coturn = let
+        runConfig = "/run/coturn/turnserver.cfg";
+      in {
+        description = "coturn TURN server";
+        after = [ "network-online.target" ];
+        wants = [ "network-online.target" ];
+        wantedBy = [ "multi-user.target" ];
+
+        unitConfig = {
+          Documentation = "man:coturn(1) man:turnadmin(1) man:turnserver(1)";
+        };
+
+        script = ''
+          cat ${configFile} > ${runConfig}
+          ${optionalString (cfg.static-auth-secret-file != null) ''
+            ${pkgs.replace-secret}/bin/replace-secret \
+              "#static-auth-secret#" \
+              ${cfg.static-auth-secret-file} \
+              ${runConfig}
+          '' }
+          chmod 640 ${runConfig}
+
+          exec ${pkgs.coturn}/bin/turnserver -c ${runConfig}
+        '';
+        serviceConfig = {
+          Type = "simple";
+          RuntimeDirectory = "turnserver";
+          User = "turnserver";
+          Group = "turnserver";
+          AmbientCapabilities =
+            mkIf (
+              cfg.listening-port < 1024 ||
+              cfg.alt-listening-port < 1024 ||
+              cfg.tls-listening-port < 1024 ||
+              cfg.alt-tls-listening-port < 1024 ||
+              cfg.min-port < 1024
+            ) "cap_net_bind_service";
+          Restart = "on-abort";
+        };
+      };
+    systemd.tmpfiles.rules = [
+      "d  /run/coturn 0700 turnserver turnserver - -"
+    ];
+  }]));
+}