src/java.net.http/share/classes/jdk/internal/net/http/websocket/StatusCodes.java

/*
 * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package jdk.internal.net.http.websocket;

/*
 * Utilities for WebSocket status codes.
 *
 *     1. https://tools.ietf.org/html/rfc6455#section-7.4
 *     2. http://www.iana.org/assignments/websocket/websocket.xhtml#close-code-number
 */
final class StatusCodes {

    static final int PROTOCOL_ERROR    = 1002;
    static final int NO_STATUS_CODE    = 1005;
    static final int CLOSED_ABNORMALLY = 1006;
    static final int NOT_CONSISTENT    = 1007;

    private StatusCodes() { }

    static boolean isLegalToSendFromClient(int code) {
        if (!isLegal(code)) {
            return false;
        }
        // Codes from unreserved range
        if (code > 4999) {
            return false;
        }
        // Codes below are not allowed to be sent using a WebSocket client API
        switch (code) {
            case PROTOCOL_ERROR:
            case NOT_CONSISTENT:
            case 1003:
            case 1009:
            case 1010:
            case 1012:  // code sent by servers
            case 1013:  // code sent by servers
            case 1014:  // code sent by servers
                return false;
            default:
                return true;
        }
    }

    static boolean isLegalToReceiveFromServer(int code) {
        if (!isLegal(code)) {
            return false;
        }
        return code != 1010;  // code sent by clients
    }

    private static boolean isLegal(int code) {
        // 2-byte unsigned integer excluding first 1000 numbers from the range
        // [0, 999] which are never used
        if (code < 1000 || code > 65535) {
            return false;
        }
        // Codes from the range below has no known meaning under the WebSocket
        // specification (i.e. unassigned/undefined)
        if ((code >= 1016 && code <= 2999) || code == 1004) {
            return false;
        }
        // Codes below cannot appear on the wire. It's always an error either
        // to send a frame with such a code or to receive one.
        switch (code) {
            case NO_STATUS_CODE:
            case CLOSED_ABNORMALLY:
            case 1015:
                return false;
            default:
                return true;
        }
    }
}