content: /*
   * Copyright (C) 2019 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.ike.ikev2.message;
  
  import com.android.ike.ikev2.exceptions.IkeException;
  import com.android.ike.ikev2.exceptions.InvalidSyntaxException;
  
  import java.nio.ByteBuffer;
  
  /**
   * IkeDeletePayload represents a Delete Payload.
   *
   * <p>As instructed in RFC 7296, deletion of the IKE SA is indicated by a protocol ID of 1 (IKE) but
   * no SPIs. Deletion of a Child SA will contain the IPsec protocol ID and SPIs of inbound IPsec
   * packets. Since IKE library only supports negotiating Child SA using ESP, only the protocol ID of
   * 3 (ESP) is used for deleting Child SA.
   *
   * @see <a href="https://tools.ietf.org/html/rfc7296#section-3.11">RFC 7296, Internet Key Exchange
   *     Protocol Version 2 (IKEv2)</a>
   */
  public final class IkeDeletePayload extends IkePayload {
  
      @ProtocolId public final int protocolId;
      public final byte spiSize;
      public final int numSpi;
      public final int[] spisToDelete;
  
      /**
       * Construct an instance of IkeDeletePayload from decoding inbound IKE packet.
       *
       * <p>NegativeArraySizeException and BufferUnderflowException will be caught in {@link
       * IkeMessage}
       *
       * @param critical indicates if this payload is critical. Ignored in supported payload as
       *     instructed by the RFC 7296.
       * @param payloadBody payload body in byte array
       * @throws IkeException if there is any error
       */
      IkeDeletePayload(boolean critical, byte[] payloadBody) throws IkeException {
          super(PAYLOAD_TYPE_DELETE, critical);
  
          ByteBuffer inputBuffer = ByteBuffer.wrap(payloadBody);
  
          protocolId = Byte.toUnsignedInt(inputBuffer.get());
          spiSize = inputBuffer.get();
          numSpi = Short.toUnsignedInt(inputBuffer.getShort());
          spisToDelete = new int[numSpi];
  
          switch (protocolId) {
              case PROTOCOL_ID_IKE:
                  // Delete payload for IKE SA must not include SPI.
                  if (spiSize != SPI_LEN_NOT_INCLUDED
                          || numSpi != 0
                          || inputBuffer.remaining() != 0) {
                      throw new InvalidSyntaxException("Invalid Delete IKE Payload.");
                  }
                  break;
              case PROTOCOL_ID_ESP:
                  // Delete payload for Child SA must include SPI
                  if (spiSize != SPI_LEN_IPSEC
                          || numSpi == 0
                          || inputBuffer.remaining() != SPI_LEN_IPSEC * numSpi) {
                      throw new InvalidSyntaxException("Invalid Delete Child Payload.");
                  }
  
                  for (int i = 0; i < numSpi; i++) {
                      spisToDelete[i] = inputBuffer.getInt();
                  }
                  break;
              default:
                  throw new InvalidSyntaxException("Unrecognized protocol in Delete Payload.");
          }
      }
  
      // TODO: Add a constructor for building outbound IKE message.
  
      /**
       * Encode Delete Payload to ByteBuffer.
       *
       * @param nextPayload type of payload that follows this payload.
       * @param byteBuffer destination ByteBuffer that stores encoded payload.
       */
      @Override
      protected void encodeToByteBuffer(@PayloadType int nextPayload, ByteBuffer byteBuffer) {
          throw new UnsupportedOperationException("Operation not supported.");
          // TODO: Implement it.
      }
  
      /**
       * Get entire payload length.
       *
       * @return entire payload length.
       */
      @Override
      protected int getPayloadLength() {
          throw new UnsupportedOperationException("Operation not supported.");
          // TODO: Implement it.
      }
  
      /**
       * Return the payload type as a String.
       *
       * @return the payload type as a String.
       */
      @Override
      public String getTypeString() {
          return "Delete Payload";
      }
  }
  