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;
  
  import android.net.IpSecManager.UdpEncapsulationSocket;
  
  import com.android.ike.ikev2.message.IkePayload;
  
  import java.net.InetAddress;
  import java.util.LinkedList;
  import java.util.List;
  
  /**
   * IkeSessionOptions contains all user provided configurations for negotiating an IKE SA.
   *
   * <p>TODO: Make this doc more user-friendly.
   */
  public final class IkeSessionOptions {
      private final InetAddress mServerAddress;
      private final UdpEncapsulationSocket mUdpEncapSocket;
      private final SaProposal[] mSaProposals;
      private final boolean mIsIkeFragmentationSupported;
  
      private IkeSessionOptions(
              InetAddress serverAddress,
              UdpEncapsulationSocket udpEncapsulationSocket,
              SaProposal[] proposals,
              boolean isIkeFragmentationSupported) {
          mServerAddress = serverAddress;
          mUdpEncapSocket = udpEncapsulationSocket;
          mSaProposals = proposals;
          mIsIkeFragmentationSupported = isIkeFragmentationSupported;
      }
  
      /** Package private */
      InetAddress getServerAddress() {
          return mServerAddress;
      }
      /** Package private */
      UdpEncapsulationSocket getUdpEncapsulationSocket() {
          return mUdpEncapSocket;
      }
      /** Package private */
      SaProposal[] getSaProposals() {
          return mSaProposals;
      }
      /** Package private */
      boolean isIkeFragmentationSupported() {
          return mIsIkeFragmentationSupported;
      }
  
      /** This class can be used to incrementally construct a IkeSessionOptions. */
      public static final class Builder {
          private final InetAddress mServerAddress;
          private final UdpEncapsulationSocket mUdpEncapSocket;
          private final List<SaProposal> mSaProposalList = new LinkedList<>();
  
          private boolean mIsIkeFragmentationSupported = false;
  
          /**
           * Returns a new Builder for an IkeSessionOptions.
           *
           * @param serverAddress IP address of remote IKE server.
           * @param udpEncapsulationSocket {@link IpSecManager.UdpEncapsulationSocket} for sending and
           *     receiving IKE message.
           * @return Builder for an IkeSessionOptions.
           */
          public Builder(InetAddress serverAddress, UdpEncapsulationSocket udpEncapsulationSocket) {
              mServerAddress = serverAddress;
              mUdpEncapSocket = udpEncapsulationSocket;
          }
  
          /**
           * Adds an IKE SA proposal to IkeSessionOptions being built.
           *
           * @param proposal IKE SA proposal.
           * @return Builder for an IkeSessionOptions.
           * @throws IllegalArgumentException if input proposal is not IKE SA proposal.
           */
          public Builder addSaProposal(SaProposal proposal) {
              if (proposal.getProtocolId() != IkePayload.PROTOCOL_ID_IKE) {
                  throw new IllegalArgumentException(
                          "Expected IKE SA Proposal but received Child SA proposal");
              }
              mSaProposalList.add(proposal);
              return this;
          }
  
          /**
           * Validates, builds and returns the IkeSessionOptions
           *
           * @return IkeSessionOptions the validated IkeSessionOptions
           * @throws IllegalStateException if no IKE SA proposal is provided
           */
          public IkeSessionOptions build() {
              if (mSaProposalList.isEmpty()) {
                  throw new IllegalArgumentException("IKE SA proposal not found");
              }
              return new IkeSessionOptions(
                      mServerAddress,
                      mUdpEncapSocket,
                      mSaProposalList.toArray(new SaProposal[mSaProposalList.size()]),
                      mIsIkeFragmentationSupported);
          }
  
          // TODO: add methods for supporting IKE fragmentation.
      }
  }
  