content: /*
   * Copyright (C) 2016 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.server.wifi.hotspot2.anqp;
  
  import com.android.internal.annotations.VisibleForTesting;
  import com.android.server.wifi.ByteBufferReader;
  import com.android.server.wifi.hotspot2.anqp.eap.EAPMethod;
  
  import java.net.ProtocolException;
  import java.nio.BufferUnderflowException;
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  
  /**
   * The NAI Realm Data ANQP sub-element, IEEE802.11-2012 section 8.4.4.10 figure 8-418.
   *
   * Format:
   * | Length | Encoding | NAIRealm Length | NAIRealm | EAPMethod Count | EAPMethod #1 (optional) |
   *     2         1               1         variable          1                  variable
   */
  public class NAIRealmData {
      /**
       * Mask for determining NAI Realm String encoding type.
       */
      @VisibleForTesting
      public static final int NAI_ENCODING_UTF8_MASK = 0x1;
  
      @VisibleForTesting
      public static final String NAI_REALM_STRING_SEPARATOR = ";";
  
      private final List<String> mRealms;
      private final List<EAPMethod> mEAPMethods;
  
      @VisibleForTesting
      public NAIRealmData(List<String> realms, List<EAPMethod> eapMethods) {
          mRealms = realms;
          mEAPMethods = eapMethods;
      }
  
      /**
       * Parse a NAIRealmData from the given buffer.
       *
       * @param payload The byte buffer to read from
       * @return {@link NAIRealmElement}
       * @throws BufferUnderflowException
       * @throws ProtocolException
       */
      public static NAIRealmData parse(ByteBuffer payload) throws ProtocolException {
          // Read and verify the length field.
          int length = (int) ByteBufferReader.readInteger(payload, ByteOrder.LITTLE_ENDIAN, 2)
                  & 0xFFFF;
          if (length > payload.remaining()) {
              throw new ProtocolException("Invalid data length: " + length);
          }
  
          // Read the encoding field.
          boolean utf8 = (payload.get() & NAI_ENCODING_UTF8_MASK) != 0;
  
          // Read the realm string.
          String realm = ByteBufferReader.readStringWithByteLength(
                  payload, utf8 ? StandardCharsets.UTF_8 : StandardCharsets.US_ASCII);
          List<String> realmList = Arrays.asList(realm.split(NAI_REALM_STRING_SEPARATOR));
  
          // Read the EAP methods.
          int methodCount = payload.get() & 0xFF;
          List<EAPMethod> eapMethodList = new ArrayList<>();
          while (methodCount > 0) {
              eapMethodList.add(EAPMethod.parse(payload));
              methodCount--;
          }
          return new NAIRealmData(realmList, eapMethodList);
      }
  
      public List<String> getRealms() {
          return Collections.unmodifiableList(mRealms);
      }
  
      public List<EAPMethod> getEAPMethods() {
          return Collections.unmodifiableList(mEAPMethods);
      }
  
      @Override
      public boolean equals(Object thatObject) {
          if (this == thatObject) {
              return true;
          }
          if (!(thatObject instanceof NAIRealmData)) {
              return false;
          }
          NAIRealmData that = (NAIRealmData) thatObject;
          return mRealms.equals(that.mRealms) && mEAPMethods.equals(that.mEAPMethods);
      }
  
      @Override
      public int hashCode() {
          return mRealms.hashCode() * 31 + mEAPMethods.hashCode();
      }
  
      @Override
      public String toString() {
          return "NAIRealmElement{mRealms=" + mRealms + " mEAPMethods=" + mEAPMethods + "}";
      }
  }
  