nginx: add vhost.http3

Co-authored-by: Sandro <sandro.jaeckel@gmail.com>

nixos/modules/services/web-servers/nginx/default.nix

@@ -249,7 +249,15 @@ let
           + optionalString (ssl && vhost.http2) "http2 "
           + optionalString vhost.default "default_server "
           + optionalString (extraParameters != []) (concatStringsSep " " extraParameters)
-          + ";";
+          + ";"
+          + (if ssl && vhost.http3 then ''
+          # UDP listener for **QUIC+HTTP/3
+          listen ${addr}:${toString port} http3 reuseport;
+          # Advertise that HTTP/3 is available
+          add_header Alt-Svc 'h3=":443"';
+          # Sent when QUIC was used
+          add_header QUIC-Status $quic;
+          '' else "");
 
         redirectListen = filter (x: !x.ssl) defaultListen;
 

nixos/modules/services/web-servers/nginx/vhost-options.nix

@@ -151,6 +151,19 @@ with lib;
       '';
     };
 
+    http3 = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Whether to enable HTTP 3.
+        This requires using <literal>pkgs.nginxQuic</literal> package
+        which can be achived by setting <literal>services.nginx.package = pkgs.nginxQuic;</literal>.
+        Note that HTTP 3 support is experimental and
+        *not* yet recommended for production.
+        Read more at https://quic.nginx.org/
+      '';
+    };
+
     root = mkOption {
       type = types.nullOr types.path;
       default = null;