content: /*
   * Copyright (C) 2018 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.IkeIdentification;
  import com.android.ike.ikev2.IkeIdentification.IkeIpv4AddrIdentification;
  import com.android.ike.ikev2.IkeIdentification.IkeIpv6AddrIdentification;
  import com.android.ike.ikev2.exceptions.AuthenticationFailedException;
  import com.android.ike.ikev2.exceptions.IkeException;
  import com.android.ike.ikev2.exceptions.InvalidSyntaxException;
  import com.android.ike.ikev2.message.IkePayload.PayloadType;
  
  import java.nio.ByteBuffer;
  
  /**
   * IkeIdPayload represents an Identification Initiator Payload or an Identification Responder
   * Payload.
   *
   * <p>Identification Initiator Payload and Identification Responder Payload have same format but
   * different payload type.
   *
   * @see <a href="https://tools.ietf.org/html/rfc7296#section-3.5">RFC 7296, Internet Key Exchange
   *     Protocol Version 2 (IKEv2)</a>
   */
  public final class IkeIdPayload extends IkePayload {
      // Length of ID Payload header in octets.
      private static final int ID_HEADER_LEN = 4;
      // Length of reserved field in octets.
      private static final int ID_HEADER_RESERVED_LEN = 3;
  
      public final IkeIdentification ikeId;
  
      /**
       * Construct IkeIdPayload for received IKE packet in the context of {@link IkePayloadFactory}.
       *
       * @param critical indicates if it is a critical payload.
       * @param payloadBody payload body in byte array.
       * @param isInitiator indicates whether this payload contains the ID of IKE initiator or IKE
       *     responder.
       * @throws IkeException for decoding error.
       */
      IkeIdPayload(boolean critical, byte[] payloadBody, boolean isInitiator) throws IkeException {
          super((isInitiator ? PAYLOAD_TYPE_ID_INITIATOR : PAYLOAD_TYPE_ID_RESPONDER), critical);
          // TODO: b/119791832 Add helper method for checking payload body length in superclass.
          if (payloadBody.length <= ID_HEADER_LEN) {
              throw new InvalidSyntaxException(getTypeString() + " is too short.");
          }
  
          ByteBuffer inputBuffer = ByteBuffer.wrap(payloadBody);
          int idType = Byte.toUnsignedInt(inputBuffer.get());
  
          // Skip reserved field
          inputBuffer.get(new byte[ID_HEADER_RESERVED_LEN]);
  
          byte[] idData = new byte[payloadBody.length - ID_HEADER_LEN];
          inputBuffer.get(idData);
  
          switch (idType) {
              case IkeIdentification.ID_TYPE_IPV4_ADDR:
                  ikeId = new IkeIpv4AddrIdentification(idData);
                  return;
              case IkeIdentification.ID_TYPE_FQDN:
                  // Fall through
              case IkeIdentification.ID_TYPE_RFC822_ADDR:
                  throw new UnsupportedOperationException("ID type is not supported currently.");
              case IkeIdentification.ID_TYPE_IPV6_ADDR:
                  ikeId = new IkeIpv6AddrIdentification(idData);
                  return;
              case IkeIdentification.ID_TYPE_DER_ASN1_DN:
                  // Fall through
              case IkeIdentification.ID_TYPE_DER_ASN1_GN:
                  // Fall through
              case IkeIdentification.ID_TYPE_KEY_ID:
                  throw new UnsupportedOperationException("ID type is not supported currently.");
              default:
                  throw new AuthenticationFailedException("Unsupported ID type: " + idType);
          }
      }
  
      /**
       * Construct IkeIdPayload for an outbound IKE packet.
       *
       * @param isInitiator indicates whether this payload contains the ID of IKE initiator or IKE
       *     responder.
       * @param ikeId the IkeIdentification.
       */
      public IkeIdPayload(boolean isInitiator, IkeIdentification ikeId) {
          super((isInitiator ? PAYLOAD_TYPE_ID_INITIATOR : PAYLOAD_TYPE_ID_RESPONDER), false);
          this.ikeId = ikeId;
      }
  
      /**
       * Encode Identification 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) {
          encodePayloadHeaderToByteBuffer(nextPayload, getPayloadLength(), byteBuffer);
          byteBuffer
                  .put((byte) ikeId.idType)
                  .put(new byte[ID_HEADER_RESERVED_LEN])
                  .put(ikeId.getEncodedIdData());
      }
  
      /**
       * Get entire payload length.
       *
       * @return entire payload length.
       */
      @Override
      protected int getPayloadLength() {
          return GENERIC_HEADER_LENGTH + ID_HEADER_LEN + ikeId.getEncodedIdData().length;
      }
  
      /**
       * Return the payload type as a String.
       *
       * @return the payload type as a String.
       */
      @Override
      public String getTypeString() {
          switch (payloadType) {
              case PAYLOAD_TYPE_ID_INITIATOR:
                  return "Identification Initiator Payload";
              case PAYLOAD_TYPE_ID_RESPONDER:
                  return "Identification Responder Payload";
              default:
                  // Won't reach here.
                  throw new IllegalArgumentException(
                          "Invalid Payload Type for Identification Payload.");
          }
      }
  }
  