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.eap;
  
  import com.android.internal.annotations.VisibleForTesting;
  
  import java.net.ProtocolException;
  import java.nio.BufferUnderflowException;
  import java.nio.ByteBuffer;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  
  /**
   * An EAP Method part of the NAI Realm ANQP element, specified in
   * IEEE802.11-2012 section 8.4.4.10, figure 8-420
   *
   * Format:
   * | Length | EAP Method | Auth Param Count | Auth Param #1 (optional) | ....
   *     1          1               1                 variable
   */
  public class EAPMethod {
      private final int mEAPMethodID;
      private final Map<Integer, Set<AuthParam>> mAuthParams;
  
      @VisibleForTesting
      public EAPMethod(int methodID, Map<Integer, Set<AuthParam>> authParams) {
          mEAPMethodID = methodID;
          mAuthParams = authParams;
      }
  
      /**
       * Parse a EAPMethod from the given buffer.
       *
       * @param payload The byte buffer to read from
       * @return {@link EAPMethod}
       * @throws ProtocolException
       * @throws BufferUnderflowException
       */
      public static EAPMethod parse(ByteBuffer payload) throws ProtocolException {
          // Read and verify the length field.
          int length = payload.get() & 0xFF;
          if (length > payload.remaining()) {
              throw new ProtocolException("Invalid data length: " + length);
          }
  
          int methodID = payload.get() & 0xFF;
          int authCount = payload.get() & 0xFF;
          Map<Integer, Set<AuthParam>> authParams = new HashMap<>();
          while (authCount > 0) {
              addAuthParam(authParams, parseAuthParam(payload));
              authCount--;
          }
          return new EAPMethod(methodID, authParams);
      }
  
      /**
       * Parse a AuthParam from the given buffer.
       *
       * Format:
       * | Auth ID | Length | Value |
       *      1         1    variable
       *
       * @param payload The byte buffer to read from
       * @return {@link AuthParam}
       * @throws BufferUnderflowException
       * @throws ProtocolException
       */
      private static AuthParam parseAuthParam(ByteBuffer payload) throws ProtocolException {
          int authID = payload.get() & 0xFF;
          int length = payload.get() & 0xFF;
          switch (authID) {
              case AuthParam.PARAM_TYPE_EXPANDED_EAP_METHOD:
                  return ExpandedEAPMethod.parse(payload, length, false);
              case AuthParam.PARAM_TYPE_NON_EAP_INNER_AUTH_TYPE:
                  return NonEAPInnerAuth.parse(payload, length);
              case AuthParam.PARAM_TYPE_INNER_AUTH_EAP_METHOD_TYPE:
                  return InnerAuthEAP.parse(payload, length);
              case AuthParam.PARAM_TYPE_EXPANDED_INNER_EAP_METHOD:
                  return ExpandedEAPMethod.parse(payload, length, true);
              case AuthParam.PARAM_TYPE_CREDENTIAL_TYPE:
                  return CredentialType.parse(payload, length, false);
              case AuthParam.PARAM_TYPE_TUNNELED_EAP_METHOD_CREDENTIAL_TYPE:
                  return CredentialType.parse(payload, length, true);
              case AuthParam.PARAM_TYPE_VENDOR_SPECIFIC:
                  return VendorSpecificAuth.parse(payload, length);
              default:
                  throw new ProtocolException("Unknow Auth Type ID: " + authID);
          }
      }
  
      /**
       * Add an AuthParam to a map of authentication parameters.  It is possible to have
       * multiple authentication parameters for the same type.
       *
       * @param paramsMap The authentication parameter map to add the new parameter to
       * @param authParam The authentication parameter to add
       */
      private static void addAuthParam(Map<Integer, Set<AuthParam>> paramsMap,
              AuthParam authParam) {
          Set<AuthParam> authParams = paramsMap.get(authParam.getAuthTypeID());
          if (authParams == null) {
              authParams = new HashSet<>();
              paramsMap.put(authParam.getAuthTypeID(), authParams);
          }
          authParams.add(authParam);
      }
  
      public Map<Integer, Set<AuthParam>> getAuthParams() {
          return Collections.unmodifiableMap(mAuthParams);
      }
  
      public int getEAPMethodID() {
          return mEAPMethodID;
      }
  
      @Override
      public boolean equals(Object thatObject) {
          if (thatObject == this) {
              return true;
          }
          if (!(thatObject instanceof EAPMethod)) {
              return false;
          }
          EAPMethod that = (EAPMethod) thatObject;
          return mEAPMethodID == that.mEAPMethodID && mAuthParams.equals(that.mAuthParams);
      }
  
      @Override
      public int hashCode() {
          return mEAPMethodID * 31 + mAuthParams.hashCode();
      }
  
      @Override
      public String toString() {
          return "EAPMethod{mEAPMethodID=" + mEAPMethodID + " mAuthParams=" + mAuthParams + "}";
      }
  }
  