nixos/moq-relay: init moq-relay systemd service

nixos/modules/module-list.nix

@@ -1340,6 +1340,7 @@
   ./services/video/photonvision.nix
   ./services/video/replay-sorcery.nix
   ./services/video/mediamtx.nix
+  ./services/video/moq-relay.nix
   ./services/video/unifi-video.nix
   ./services/video/v4l2-relayd.nix
   ./services/wayland/cage.nix

nixos/modules/services/video/moq-relay.nix

@@ -0,0 +1,100 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  cfg = config.services.moq-relay;
+in
+{
+  options.services.moq-relay = {
+    enable = lib.mkEnableOption "moq-relay";
+    port = lib.mkOption {
+      type = lib.types.port;
+      default = 443;
+      description = "Relay server port";
+    };
+    user = lib.mkOption {
+      type = with lib.types; uniq str;
+      description = ''
+        User account that runs moq-relay.
+
+        ::: {.note}
+        This user must have access to the TLS certificate and key.
+        :::
+      '';
+    };
+    group = lib.mkOption {
+      type = with lib.types; uniq str;
+      description = ''
+        Group account that runs moq-relay.
+
+        ::: {.note}
+        This group must have access to the TLS certificate and key.
+        :::
+      '';
+    };
+    tls = {
+      keyPath = lib.mkOption {
+        type = lib.types.path;
+        example = "/var/lib/acme/moq-relay.example.org/key.pem";
+        description = ''
+          Path to TLS private key
+        '';
+      };
+      certPath = lib.mkOption {
+        type = lib.types.path;
+        example = "/var/lib/acme/moq-relay.example.org/cert.pem";
+        description = ''
+          Path to TLS certificate
+        '';
+      };
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    systemd.services.moq-relay = {
+      description = "Media over QUIC relay server";
+      wantedBy = [ "multi-user.target" ];
+
+      serviceConfig = {
+        User = cfg.user;
+        Group = cfg.group;
+        ExecStart = "${pkgs.moq-relay}/bin/moq-relay --bind [::]:${builtins.toString cfg.port} --tls-cert ${cfg.tls.certPath} --tls-key ${cfg.tls.keyPath}";
+        Restart = "on-failure";
+        RestartSec = "1";
+
+        # hardening
+        RemoveIPC = true;
+        CapabilityBoundingSet = [ "" ];
+        DynamicUser = true;
+        NoNewPrivileges = true;
+        PrivateDevices = true;
+        ProtectClock = true;
+        ProtectKernelLogs = true;
+        ProtectControlGroups = true;
+        ProtectKernelModules = true;
+        SystemCallArchitectures = "native";
+        SystemCallFilter = "@system-service";
+        RestrictNamespaces = true;
+        RestrictSUIDSGID = true;
+        ProtectHostname = true;
+        LockPersonality = true;
+        ProtectKernelTunables = true;
+        RestrictAddressFamilies = [
+          "AF_INET"
+          "AF_INET6"
+          "AF_UNIX"
+        ];
+        RestrictRealtime = true;
+        ProtectSystem = "strict";
+        ProtectProc = "invisible";
+        ProcSubset = "pid";
+        ProtectHome = true;
+        PrivateUsers = true;
+        PrivateTmp = true;
+      };
+    };
+  };
+}