1 files changed, 121 insertions, 0 deletions
diff --git a/nixos/modules/services/networking/syncthing-relay.nix b/nixos/modules/services/networking/syncthing-relay.nix
new file mode 100644
index 00000000000..f5ca63e7893
--- /dev/null
+++ b/nixos/modules/services/networking/syncthing-relay.nix
@@ -0,0 +1,121 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.syncthing.relay;
+
+  dataDirectory = "/var/lib/syncthing-relay";
+
+  relayOptions =
+    [
+      "--keys=${dataDirectory}"
+      "--listen=${cfg.listenAddress}:${toString cfg.port}"
+      "--status-srv=${cfg.statusListenAddress}:${toString cfg.statusPort}"
+      "--provided-by=${escapeShellArg cfg.providedBy}"
+    ]
+    ++ optional (cfg.pools != null) "--pools=${escapeShellArg (concatStringsSep "," cfg.pools)}"
+    ++ optional (cfg.globalRateBps != null) "--global-rate=${toString cfg.globalRateBps}"
+    ++ optional (cfg.perSessionRateBps != null) "--per-session-rate=${toString cfg.perSessionRateBps}"
+    ++ cfg.extraOptions;
+in {
+  ###### interface
+
+  options.services.syncthing.relay = {
+    enable = mkEnableOption "Syncthing relay service";
+
+    listenAddress = mkOption {
+      type = types.str;
+      default = "";
+      example = "1.2.3.4";
+      description = ''
+        Address to listen on for relay traffic.
+      '';
+    };
+
+    port = mkOption {
+      type = types.port;
+      default = 22067;
+      description = ''
+        Port to listen on for relay traffic. This port should be added to
+        <literal>networking.firewall.allowedTCPPorts</literal>.
+      '';
+    };
+
+    statusListenAddress = mkOption {
+      type = types.str;
+      default = "";
+      example = "1.2.3.4";
+      description = ''
+        Address to listen on for serving the relay status API.
+      '';
+    };
+
+    statusPort = mkOption {
+      type = types.port;
+      default = 22070;
+      description = ''
+        Port to listen on for serving the relay status API. This port should be
+        added to <literal>networking.firewall.allowedTCPPorts</literal>.
+      '';
+    };
+
+    pools = mkOption {
+      type = types.nullOr (types.listOf types.str);
+      default = null;
+      description = ''
+        Relay pools to join. If null, uses the default global pool.
+      '';
+    };
+
+    providedBy = mkOption {
+      type = types.str;
+      default = "";
+      description = ''
+        Human-readable description of the provider of the relay (you).
+      '';
+    };
+
+    globalRateBps = mkOption {
+      type = types.nullOr types.ints.positive;
+      default = null;
+      description = ''
+        Global bandwidth rate limit in bytes per second.
+      '';
+    };
+
+    perSessionRateBps = mkOption {
+      type = types.nullOr types.ints.positive;
+      default = null;
+      description = ''
+        Per session bandwidth rate limit in bytes per second.
+      '';
+    };
+
+    extraOptions = mkOption {
+      type = types.listOf types.str;
+      default = [];
+      description = ''
+        Extra command line arguments to pass to strelaysrv.
+      '';
+    };
+  };
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+    systemd.services.syncthing-relay = {
+      description = "Syncthing relay service";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+
+      serviceConfig = {
+        DynamicUser = true;
+        StateDirectory = baseNameOf dataDirectory;
+
+        Restart = "on-failure";
+        ExecStart = "${pkgs.syncthing-relay}/bin/strelaysrv ${concatStringsSep " " relayOptions}";
+      };
+    };
+  };
+}