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Commit 8926b4c9 authored by Xiao Ma's avatar Xiao Ma Committed by Gerrit Code Review
Browse files

Merge "Provide RRO configuration to send DHCP client hostname option."

parents 609972ba 8bcd6735

res/values/config.xml

+3 −0
Original line number Diff line number Diff line
@@ -46,4 +46,7 @@ 
    <!-- Set to true if NetworkMonitor needs to load the resource by neighbor mcc when device

         doesn't have a SIM card inserted. -->

    <bool name="config_no_sim_card_uses_neighbor_mcc">false</bool>



    <!-- Configuration for including DHCP client hostname option -->

    <bool name="config_dhcp_client_hostname">false</bool>

</resources>

res/values/overlayable.xml

+10 −0
Original line number Diff line number Diff line
@@ -24,6 +24,16 @@ 
            <item type="bool" name="config_no_sim_card_uses_neighbor_mcc"/>

            <!-- Configuration value for DhcpResults -->

            <item type="array" name="config_default_dns_servers"/>

            <!-- Configuration for including DHCP client hostname option.

            If this option is true, client hostname set in Settings.Global.DEVICE_NAME will be

            included in DHCPDISCOVER/DHCPREQUEST, otherwise, the DHCP hostname option will not

            be sent. RFC952 and RFC1123 stipulates an valid hostname should be only comprised of

            'a-z', 'A-Z' and '-', and the length should be up to 63 octets or less (RFC1035#2.3.4),

            platform will perform best-effort transliteration for other characters. Anything that

            could be used to identify the device uniquely is not recommended, e.g. user's name,

            random number and etc.

            -->

            <item type="bool" name="config_dhcp_client_hostname"/>

        </policy>

    </overlayable>

</resources>

src/android/net/dhcp/DhcpClient.java

+29 −4
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ import android.net.ipmemorystore.OnStatusListener; 
import android.net.metrics.DhcpClientEvent;

import android.net.metrics.DhcpErrorEvent;

import android.net.metrics.IpConnectivityLog;

import android.net.util.HostnameTransliterator;

import android.net.util.InterfaceParams;

import android.net.util.NetworkStackUtils;

import android.net.util.PacketReader;
@@ -76,6 +77,7 @@ import android.os.Handler; 
import android.os.Message;

import android.os.PowerManager;

import android.os.SystemClock;

import android.provider.Settings;

import android.system.ErrnoException;

import android.system.Os;

import android.util.EventLog;
@@ -312,6 +314,8 @@ public class DhcpClient extends StateMachine { 
    private final NetworkStackIpMemoryStore mIpMemoryStore;

    @Nullable

    private DhcpPacketHandler mDhcpPacketHandler;

    @Nullable

    private final String mHostname;



    // Milliseconds SystemClock timestamps used to record transition times to DhcpBoundState.

    private long mLastInitEnterTime;
@@ -355,6 +359,22 @@ public class DhcpClient extends StateMachine { 
            mNetworkStackIpMemoryStore = store;

        }



        /**

         * Get the configuration from RRO to check whether or not to send hostname option in

         * DHCPDISCOVER/DHCPREQUEST message.

         */

        public boolean getSendHostnameOption(final Context context) {

            return context.getResources().getBoolean(R.bool.config_dhcp_client_hostname);

        }



        /**

         * Get the device name from system settings.

         */

        public String getDeviceName(final Context context) {

            return Settings.Global.getString(context.getContentResolver(),

                    Settings.Global.DEVICE_NAME);

        }



        /**

         * Get a IpMemoryStore instance.

         */
@@ -433,6 +453,11 @@ public class DhcpClient extends StateMachine { 
        mRenewAlarm = makeWakeupMessage("RENEW", CMD_RENEW_DHCP);

        mRebindAlarm = makeWakeupMessage("REBIND", CMD_REBIND_DHCP);

        mExpiryAlarm = makeWakeupMessage("EXPIRY", CMD_EXPIRE_DHCP);



        // Transliterate hostname read from system settings if RRO option is enabled.

        final boolean sendHostname = deps.getSendHostnameOption(context);

        mHostname = sendHostname ? new HostnameTransliterator().transliterate(

                deps.getDeviceName(mContext)) : null;

    }



    public void registerForPreDhcpNotification() {
@@ -624,7 +649,7 @@ public class DhcpClient extends StateMachine { 
    private boolean sendDiscoverPacket() {

        final ByteBuffer packet = DhcpPacket.buildDiscoverPacket(

                DhcpPacket.ENCAP_L2, mTransactionId, getSecs(), mHwAddr,

                DO_UNICAST, REQUESTED_PARAMS, isDhcpRapidCommitEnabled());

                DO_UNICAST, REQUESTED_PARAMS, isDhcpRapidCommitEnabled(), mHostname);

        return transmitPacket(packet, "DHCPDISCOVER", DhcpPacket.ENCAP_L2, INADDR_BROADCAST);

    }
@@ -638,7 +663,7 @@ public class DhcpClient extends StateMachine { 
        final ByteBuffer packet = DhcpPacket.buildRequestPacket(

                encap, mTransactionId, getSecs(), clientAddress,

                DO_UNICAST, mHwAddr, requestedAddress,

                serverAddress, REQUESTED_PARAMS, null);

                serverAddress, REQUESTED_PARAMS, mHostname);

        String serverStr = (serverAddress != null) ? serverAddress.getHostAddress() : null;

        String description = "DHCPREQUEST ciaddr=" + clientAddress.getHostAddress() +

                             " request=" + requestedAddress.getHostAddress() +
@@ -727,7 +752,7 @@ public class DhcpClient extends StateMachine { 
        mDhcpLease = results;

        if (mDhcpLease.dnsServers.isEmpty()) {

            // supplement customized dns servers

            String[] dnsServersList =

            final String[] dnsServersList =

                    mContext.getResources().getStringArray(R.array.config_default_dns_servers);

            for (final String dnsServer : dnsServersList) {

                try {
@@ -1242,7 +1267,7 @@ public class DhcpClient extends StateMachine { 
            final Layer2PacketParcelable l2Packet = new Layer2PacketParcelable();

            final ByteBuffer packet = DhcpPacket.buildDiscoverPacket(

                    DhcpPacket.ENCAP_L2, mTransactionId, getSecs(), mHwAddr,

                    DO_UNICAST, REQUESTED_PARAMS, true /* rapid commit */);

                    DO_UNICAST, REQUESTED_PARAMS, true /* rapid commit */, mHostname);



            l2Packet.dstMacAddress = MacAddress.fromBytes(DhcpPacket.ETHER_BROADCAST);

            l2Packet.payload = packet.array();

src/android/net/dhcp/DhcpPacket.java

+30 −5
Original line number Diff line number Diff line 
/*

 * 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 android.net.dhcp;



import static com.android.server.util.NetworkStackConstants.IPV4_ADDR_ALL;
@@ -15,6 +31,8 @@ import android.text.TextUtils; 
import androidx.annotation.Nullable;

import androidx.annotation.VisibleForTesting;



import com.android.networkstack.apishim.ShimUtils;



import java.io.UnsupportedEncodingException;

import java.net.Inet4Address;

import java.net.UnknownHostException;
@@ -350,7 +368,6 @@ public abstract class DhcpPacket { 
    // Set in unit tests, to ensure that the test does not break when run on different devices and

    // on different releases.

    static String testOverrideVendorId = null;

    static String testOverrideHostname = null;



    protected DhcpPacket(int transId, short secs, Inet4Address clientIp, Inet4Address yourIp,

                         Inet4Address nextIp, Inet4Address relayIp,
@@ -724,10 +741,17 @@ public abstract class DhcpPacket { 
        return "android-dhcp-" + Build.VERSION.RELEASE;

    }



    private String getHostname() {

        if (testOverrideHostname != null) return testOverrideHostname;

    /**

     * Get the DHCP client hostname after transliteration.

     */

    @VisibleForTesting

    public String getHostname() {

        if (mHostName == null

                && !ShimUtils.isReleaseOrDevelopmentApiAbove(Build.VERSION_CODES.Q)) {

            return SystemProperties.get("net.hostname");

        }

        return mHostName;

    }



    /**

     * Adds common client TLVs.
@@ -1328,10 +1352,11 @@ public abstract class DhcpPacket { 
     */

    public static ByteBuffer buildDiscoverPacket(int encap, int transactionId,

            short secs, byte[] clientMac, boolean broadcast, byte[] expectedParams,

            boolean rapidCommit) {

            boolean rapidCommit, String hostname) {

        DhcpPacket pkt = new DhcpDiscoverPacket(transactionId, secs, INADDR_ANY /* relayIp */,

                clientMac, broadcast, INADDR_ANY /* srcIp */, rapidCommit);

        pkt.mRequestedParams = expectedParams;

        pkt.mHostName = hostname;

        return pkt.buildPacket(encap, DHCP_SERVER, DHCP_CLIENT);

    }

src/android/net/util/HostnameTransliterator.java

0 → 100644
+103 −0
Original line number Diff line number Diff line 
/*

 * 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 android.net.util;



import android.icu.text.Transliterator;

import android.text.TextUtils;

import android.util.Log;



import androidx.annotation.NonNull;

import androidx.annotation.Nullable;

import androidx.annotation.VisibleForTesting;



import java.util.Collections;

import java.util.Enumeration;

import java.util.HashSet;

import java.util.Set;



/**

 * Transliterator to display a human-readable DHCP client hostname.

 */

public class HostnameTransliterator {

    private static final String TAG = "HostnameTransliterator";



    // Maximum length of hostname to be encoded in the DHCP message. Following RFC1035#2.3.4

    // and this transliterator converts the device name to a single label, so the label length

    // limit applies to the whole hostname.

    private static final int MAX_DNS_LABEL_LENGTH = 63;



    @Nullable

    private final Transliterator mTransliterator;



    public HostnameTransliterator() {

        final Enumeration<String> availableIDs = Transliterator.getAvailableIDs();

        final Set<String> actualIds = new HashSet<>(Collections.list(availableIDs));

        final StringBuilder rules = new StringBuilder();

        if (actualIds.contains("Any-ASCII")) {

            rules.append(":: Any-ASCII; ");

        } else if (actualIds.contains("Any-Latin") && actualIds.contains("Latin-ASCII")) {

            rules.append(":: Any-Latin; :: Latin-ASCII; ");

        } else {

            Log.e(TAG, "ICU Transliterator doesn't include supported ID");

            mTransliterator = null;

            return;

        }

        mTransliterator = Transliterator.createFromRules("", rules.toString(),

                Transliterator.FORWARD);

    }



    @VisibleForTesting

    public HostnameTransliterator(Transliterator transliterator) {

        mTransliterator = transliterator;

    }



    // RFC952 and RFC1123 stipulates an valid hostname should be:

    // 1. Only contain the alphabet (A-Z, a-z), digits (0-9), minus sign (-).

    // 2. No blank or space characters are permitted as part of a name.

    // 3. The first character must be an alpha character or digit.

    // 4. The last character must not be a minus sign (-).

    private String maybeRemoveRedundantSymbols(@NonNull String string) {

        String result = string.replaceAll("[^a-zA-Z0-9-]", "-");

        result = result.replaceAll("-+", "-");

        if (result.startsWith("-")) {

            result = result.replaceFirst("-", "");

        }

        if (result.endsWith("-")) {

            result = result.substring(0, result.length() - 1);

        }

        return result;

    }



    /**

     *  Transliterate the device name to valid hostname that could be human-readable string.

     */

    public String transliterate(@NonNull String deviceName) {

        if (deviceName == null) return null;

        if (mTransliterator == null) {

            if (!deviceName.matches("\\p{ASCII}*")) return null;

            deviceName = maybeRemoveRedundantSymbols(deviceName);

            if (TextUtils.isEmpty(deviceName)) return null;

            return deviceName.length() > MAX_DNS_LABEL_LENGTH

                    ? deviceName.substring(0, MAX_DNS_LABEL_LENGTH) : deviceName;

        }



        String hostname = maybeRemoveRedundantSymbols(mTransliterator.transliterate(deviceName));

        if (TextUtils.isEmpty(hostname)) return null;

        return hostname.length() > MAX_DNS_LABEL_LENGTH

                ? hostname.substring(0, MAX_DNS_LABEL_LENGTH) : hostname;

    }

}