Support converting EapSessionConfig to/from PersistableBundle

/*

 * Copyright (C) 2021 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 android.net.vcn.persistablebundleutils;

import static com.android.internal.annotations.VisibleForTesting.Visibility;

import android.annotation.NonNull;

import android.net.eap.EapSessionConfig;

import android.net.eap.EapSessionConfig.EapMethodConfig;

import android.net.eap.EapSessionConfig.EapMsChapV2Config;

import android.os.PersistableBundle;

import com.android.internal.annotations.VisibleForTesting;

import com.android.server.vcn.util.PersistableBundleUtils;

import java.util.Objects;

/**

 * Provides utility methods to convert EapSessionConfig to/from PersistableBundle.

 *

 * @hide

 */

@VisibleForTesting(visibility = Visibility.PRIVATE)

public final class EapSessionConfigUtils {

    private static final String EAP_ID_KEY = "EAP_ID_KEY";

    private static final String EAP_MSCHAP_V2_CONFIG_KEY = "EAP_MSCHAP_V2_CONFIG_KEY";

    /** Serializes an EapSessionConfig to a PersistableBundle. */

    @NonNull

    public static PersistableBundle toPersistableBundle(@NonNull EapSessionConfig config) {

        final PersistableBundle result = new PersistableBundle();

        result.putPersistableBundle(

                EAP_ID_KEY, PersistableBundleUtils.fromByteArray(config.getEapIdentity()));

        if (config.getEapMsChapV2Config() != null) {

            result.putPersistableBundle(

                    EAP_MSCHAP_V2_CONFIG_KEY,

                    EapMsChapV2ConfigUtils.toPersistableBundle(config.getEapMsChapV2Config()));

        }

        // TODO: Handle other EAP methods: EAP-SIM, EAP-AKA, EAP-AKA', EAP-TTLS.

        return result;

    }

    /** Constructs an EapSessionConfig by deserializing a PersistableBundle. */

    @NonNull

    public static EapSessionConfig fromPersistableBundle(@NonNull PersistableBundle in) {

        Objects.requireNonNull(in, "PersistableBundle was null");

        final EapSessionConfig.Builder builder = new EapSessionConfig.Builder();

        final PersistableBundle eapIdBundle = in.getPersistableBundle(EAP_ID_KEY);

        Objects.requireNonNull(eapIdBundle, "EAP ID was null");

        builder.setEapIdentity(PersistableBundleUtils.toByteArray(eapIdBundle));

        final PersistableBundle msChapV2Bundle = in.getPersistableBundle(EAP_MSCHAP_V2_CONFIG_KEY);

        if (msChapV2Bundle != null) {

            EapMsChapV2ConfigUtils.setBuilderByReadingPersistableBundle(msChapV2Bundle, builder);

        }

        // TODO: Handle other EAP methods: EAP-SIM, EAP-AKA, EAP-AKA', EAP-TTLS.

        return builder.build();

    }

    private static class EapMethodConfigUtils {

        private static final String METHOD_TYPE = "METHOD_TYPE";

        /** Serializes an EapMethodConfig to a PersistableBundle. */

        @NonNull

        public static PersistableBundle toPersistableBundle(@NonNull EapMethodConfig config) {

            final PersistableBundle result = new PersistableBundle();

            result.putInt(METHOD_TYPE, config.getMethodType());

            return result;

        }

    }

    private static final class EapMsChapV2ConfigUtils extends EapMethodConfigUtils {

        private static final String USERNAME_KEY = "USERNAME_KEY";

        private static final String PASSWORD_KEY = "PASSWORD_KEY";

        @NonNull

        public static PersistableBundle toPersistableBundle(@NonNull EapMsChapV2Config config) {

            final PersistableBundle result = EapMethodConfigUtils.toPersistableBundle(config);

            result.putString(USERNAME_KEY, config.getUsername());

            result.putString(PASSWORD_KEY, config.getPassword());

            return result;

        }

        public static void setBuilderByReadingPersistableBundle(

                @NonNull PersistableBundle in, @NonNull EapSessionConfig.Builder builder) {

            Objects.requireNonNull(in, "PersistableBundle was null");

            builder.setEapMsChapV2Config(in.getString(USERNAME_KEY), in.getString(PASSWORD_KEY));

        }

    }

}

/*

 * Copyright (C) 2021 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 android.net.vcn.persistablebundleutils;

import static org.junit.Assert.assertEquals;

import android.net.eap.EapSessionConfig;

import android.os.PersistableBundle;

import androidx.test.filters.SmallTest;

import androidx.test.runner.AndroidJUnit4;

import org.junit.Test;

import org.junit.runner.RunWith;

import java.nio.charset.StandardCharsets;

@RunWith(AndroidJUnit4.class)

@SmallTest

public class EapSessionConfigUtilsTest {

    private static final byte[] EAP_ID = "test@android.net".getBytes(StandardCharsets.US_ASCII);

    private static final String USERNAME = "username";

    private static final String PASSWORD = "password";

    private EapSessionConfig.Builder createBuilderWithId() {

        return new EapSessionConfig.Builder().setEapIdentity(EAP_ID);

    }

    private static void verifyPersistableBundleEncodeDecodeIsLossless(EapSessionConfig config) {

        final PersistableBundle bundle = EapSessionConfigUtils.toPersistableBundle(config);

        final EapSessionConfig resultConfig = EapSessionConfigUtils.fromPersistableBundle(bundle);

        assertEquals(config, resultConfig);

    }

    @Test

    public void testSetEapMsChapV2EncodeDecodeIsLossless() throws Exception {

        final EapSessionConfig config =

                createBuilderWithId().setEapMsChapV2Config(USERNAME, PASSWORD).build();

        verifyPersistableBundleEncodeDecodeIsLossless(config);

    }

}