| /* |
| * Copyright (C) 2020 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.android.internal.net.ipsec.ike.ike3gpp; |
| |
| import android.net.ipsec.ike.exceptions.InvalidSyntaxException; |
| |
| import java.nio.ByteBuffer; |
| |
| /** |
| * Ike3gppBackoffTimerUtils contains functions needed to support 3GPP-specific Backoff Timer |
| * functionality. |
| * |
| * <p>This class is package-private. |
| */ |
| class Ike3gppBackoffTimerUtils { |
| private static final int BACKOFF_TIMER_DATA_LEN = 2; |
| private static final byte BACKOFF_TIMER_LEN = (byte) 1; |
| |
| /** |
| * Get the backoff timer byte from the specified Notify Data. |
| * |
| * @see TS 124 302 Section 8.2.9.1 for specification of BACKOFF_TIMER Notify payload. |
| * @param notifyData The Notify-Data payload from which the backoff timer value will be parsed. |
| * @return the parsed backoff timer value |
| * @throws InvalidSyntaxException if the BACKOFF_TIMER's notifyData is encoded incorrectly |
| */ |
| static byte getBackoffTimerfromNotifyData(byte[] notifyData) throws InvalidSyntaxException { |
| ByteBuffer buffer = ByteBuffer.wrap(notifyData); |
| |
| if (buffer.remaining() != BACKOFF_TIMER_DATA_LEN || buffer.get() != BACKOFF_TIMER_LEN) { |
| throw new InvalidSyntaxException("BACKOFF_TIMER payload with an invalid encoding"); |
| } |
| |
| return buffer.get(); |
| } |
| } |