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Commit f90a92bb authored by Remi NGUYEN VAN's avatar Remi NGUYEN VAN
Browse files

Send hostname and MTU options in DHCP ACK/OFFER 

The hostname option is only sent when requested in the requested
parameters option. This matches current behavior.

Test: with aosp/763982, regression tests now all pass
      atest FrameworksNetTest
Bug: b/109584964
Change-Id: I793173fa893750ddbe72be09f4c2d70e5b285837
parent c457d8c9

services/net/java/android/net/dhcp/DhcpPacket.java

+35 −2
Original line number Diff line number Diff line 
package android.net.dhcp;



import static android.net.util.NetworkConstants.IPV4_MAX_MTU;

import static android.net.util.NetworkConstants.IPV4_MIN_MTU;



import android.annotation.Nullable;

import android.net.DhcpResults;

import android.net.LinkAddress;
@@ -380,6 +383,26 @@ public abstract class DhcpPacket { 
        return clientId;

    }



    /**

     * Returns whether a parameter is included in the parameter request list option of this packet.

     *

     * <p>If there is no parameter request list option in the packet, false is returned.

     *

     * @param paramId ID of the parameter, such as {@link #DHCP_MTU} or {@link #DHCP_HOST_NAME}.

     */

    public boolean hasRequestedParam(byte paramId) {

        if (mRequestedParams == null) {

            return false;

        }



        for (byte reqParam : mRequestedParams) {

            if (reqParam == paramId) {

                return true;

            }

        }

        return false;

    }



    /**

     * Creates a new L3 packet (including IP header) containing the

     * DHCP udp packet.  This method relies upon the delegated method
@@ -696,7 +719,11 @@ public abstract class DhcpPacket { 
        addTlv(buf, DHCP_ROUTER, mGateways);

        addTlv(buf, DHCP_DNS_SERVER, mDnsServers);

        addTlv(buf, DHCP_DOMAIN_NAME, mDomainName);

        addTlv(buf, DHCP_HOST_NAME, mHostName);

        addTlv(buf, DHCP_VENDOR_INFO, mVendorInfo);

        if (mMtu != null && Short.toUnsignedInt(mMtu) >= IPV4_MIN_MTU) {

            addTlv(buf, DHCP_MTU, mMtu);

        }

    }



    /**
@@ -1259,7 +1286,8 @@ public abstract class DhcpPacket { 
        boolean broadcast, Inet4Address serverIpAddr, Inet4Address relayIp,

        Inet4Address yourIp, byte[] mac, Integer timeout, Inet4Address netMask,

        Inet4Address bcAddr, List<Inet4Address> gateways, List<Inet4Address> dnsServers,

        Inet4Address dhcpServerIdentifier, String domainName, boolean metered) {

        Inet4Address dhcpServerIdentifier, String domainName, String hostname, boolean metered,

        short mtu) {

        DhcpPacket pkt = new DhcpOfferPacket(

                transactionId, (short) 0, broadcast, serverIpAddr, relayIp,

                INADDR_ANY /* clientIp */, yourIp, mac);
@@ -1267,9 +1295,11 @@ public abstract class DhcpPacket { 
        pkt.mDnsServers = dnsServers;

        pkt.mLeaseTime = timeout;

        pkt.mDomainName = domainName;

        pkt.mHostName = hostname;

        pkt.mServerIdentifier = dhcpServerIdentifier;

        pkt.mSubnetMask = netMask;

        pkt.mBroadcastAddress = bcAddr;

        pkt.mMtu = mtu;

        if (metered) {

            pkt.mVendorInfo = VENDOR_INFO_ANDROID_METERED;

        }
@@ -1283,7 +1313,8 @@ public abstract class DhcpPacket { 
        boolean broadcast, Inet4Address serverIpAddr, Inet4Address relayIp, Inet4Address yourIp,

        Inet4Address requestClientIp, byte[] mac, Integer timeout, Inet4Address netMask,

        Inet4Address bcAddr, List<Inet4Address> gateways, List<Inet4Address> dnsServers,

        Inet4Address dhcpServerIdentifier, String domainName, boolean metered) {

        Inet4Address dhcpServerIdentifier, String domainName, String hostname, boolean metered,

        short mtu) {

        DhcpPacket pkt = new DhcpAckPacket(

                transactionId, (short) 0, broadcast, serverIpAddr, relayIp, requestClientIp, yourIp,

                mac);
@@ -1291,9 +1322,11 @@ public abstract class DhcpPacket { 
        pkt.mDnsServers = dnsServers;

        pkt.mLeaseTime = timeout;

        pkt.mDomainName = domainName;

        pkt.mHostName = hostname;

        pkt.mSubnetMask = netMask;

        pkt.mServerIdentifier = dhcpServerIdentifier;

        pkt.mBroadcastAddress = bcAddr;

        pkt.mMtu = mtu;

        if (metered) {

            pkt.mVendorInfo = VENDOR_INFO_ANDROID_METERED;

        }

services/net/java/android/net/dhcp/DhcpServer.java

+21 −2
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ import static android.net.NetworkUtils.getBroadcastAddress; 
import static android.net.NetworkUtils.getPrefixMaskAsInet4Address;

import static android.net.TrafficStats.TAG_SYSTEM_DHCP_SERVER;

import static android.net.dhcp.DhcpPacket.DHCP_CLIENT;

import static android.net.dhcp.DhcpPacket.DHCP_HOST_NAME;

import static android.net.dhcp.DhcpPacket.DHCP_SERVER;

import static android.net.dhcp.DhcpPacket.ENCAP_BOOTP;

import static android.net.dhcp.DhcpPacket.INFINITE_LEASE;
@@ -46,6 +47,7 @@ import android.os.Message; 
import android.os.SystemClock;

import android.system.ErrnoException;

import android.system.Os;

import android.text.TextUtils;



import com.android.internal.annotations.VisibleForTesting;

import com.android.internal.util.HexDump;
@@ -350,6 +352,19 @@ public class DhcpServer { 
        return isEmpty(request.mClientIp) && (request.mBroadcast || isEmpty(lease.getNetAddr()));

    }



    /**

     * Get the hostname from a lease if non-empty and requested in the incoming request.

     * @param request The incoming request.

     * @return The hostname, or null if not requested or empty.

     */

    @Nullable

    private static String getHostnameIfRequested(@NonNull DhcpPacket request,

            @NonNull DhcpLease lease) {

        return request.hasRequestedParam(DHCP_HOST_NAME) && !TextUtils.isEmpty(lease.getHostname())

                ? lease.getHostname()

                : null;

    }



    private boolean transmitOffer(@NonNull DhcpPacket request, @NonNull DhcpLease lease,

            @NonNull MacAddress clientMac) {

        final boolean broadcastFlag = getBroadcastFlag(request, lease);
@@ -358,12 +373,14 @@ public class DhcpServer { 
                getPrefixMaskAsInet4Address(mServingParams.serverAddr.getPrefixLength());

        final Inet4Address broadcastAddr = getBroadcastAddress(

                mServingParams.getServerInet4Addr(), mServingParams.serverAddr.getPrefixLength());

        final String hostname = getHostnameIfRequested(request, lease);

        final ByteBuffer offerPacket = DhcpPacket.buildOfferPacket(

                ENCAP_BOOTP, request.mTransId, broadcastFlag, mServingParams.getServerInet4Addr(),

                request.mRelayIp, lease.getNetAddr(), request.mClientMac, timeout, prefixMask,

                broadcastAddr, new ArrayList<>(mServingParams.defaultRouters),

                new ArrayList<>(mServingParams.dnsServers),

                mServingParams.getServerInet4Addr(), null /* domainName */, mServingParams.metered);

                mServingParams.getServerInet4Addr(), null /* domainName */, hostname,

                mServingParams.metered, (short) mServingParams.linkMtu);



        return transmitOfferOrAckPacket(offerPacket, request, lease, clientMac, broadcastFlag);

    }
@@ -374,13 +391,15 @@ public class DhcpServer { 
        // transmitOffer above

        final boolean broadcastFlag = getBroadcastFlag(request, lease);

        final int timeout = getLeaseTimeout(lease);

        final String hostname = getHostnameIfRequested(request, lease);

        final ByteBuffer ackPacket = DhcpPacket.buildAckPacket(ENCAP_BOOTP, request.mTransId,

                broadcastFlag, mServingParams.getServerInet4Addr(), request.mRelayIp,

                lease.getNetAddr(), request.mClientIp, request.mClientMac, timeout,

                mServingParams.getPrefixMaskAsAddress(), mServingParams.getBroadcastAddress(),

                new ArrayList<>(mServingParams.defaultRouters),

                new ArrayList<>(mServingParams.dnsServers),

                mServingParams.getServerInet4Addr(), null /* domainName */, mServingParams.metered);

                mServingParams.getServerInet4Addr(), null /* domainName */, hostname,

                mServingParams.metered, (short) mServingParams.linkMtu);



        return transmitOfferOrAckPacket(ackPacket, request, lease, clientMac, broadcastFlag);

    }

tests/net/java/android/net/dhcp/DhcpPacketTest.java

+29 −8
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ import static org.junit.Assert.assertNull; 
import static org.junit.Assert.assertTrue;

import static org.junit.Assert.fail;



import android.annotation.Nullable;

import android.net.DhcpResults;

import android.net.LinkAddress;

import android.net.NetworkUtils;
@@ -37,6 +38,7 @@ import com.android.internal.util.HexDump; 
import java.io.ByteArrayOutputStream;

import java.net.Inet4Address;

import java.nio.ByteBuffer;

import java.nio.charset.Charset;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;
@@ -56,6 +58,8 @@ public class DhcpPacketTest { 
    private static final Inet4Address NETMASK = getPrefixMaskAsInet4Address(PREFIX_LENGTH);

    private static final Inet4Address BROADCAST_ADDR = getBroadcastAddress(

            SERVER_ADDR, PREFIX_LENGTH);

    private static final String HOSTNAME = "testhostname";

    private static final short MTU = 1500;

    // Use our own empty address instead of Inet4Address.ANY or INADDR_ANY to ensure that the code

    // doesn't use == instead of equals when comparing addresses.

    private static final Inet4Address ANY = (Inet4Address) v4Address("0.0.0.0");
@@ -960,7 +964,8 @@ public class DhcpPacketTest { 
        assertTrue(msg, Arrays.equals(expected, actual));

    }



    public void checkBuildOfferPacket(int leaseTimeSecs) throws Exception {

    public void checkBuildOfferPacket(int leaseTimeSecs, @Nullable String hostname)

            throws Exception {

        final int renewalTime = (int) (Integer.toUnsignedLong(leaseTimeSecs) / 2);

        final int rebindingTime = (int) (Integer.toUnsignedLong(leaseTimeSecs) * 875 / 1000);

        final int transactionId = 0xdeadbeef;
@@ -971,7 +976,8 @@ public class DhcpPacketTest { 
                CLIENT_MAC, leaseTimeSecs, NETMASK /* netMask */,

                BROADCAST_ADDR /* bcAddr */, Collections.singletonList(SERVER_ADDR) /* gateways */,

                Collections.singletonList(SERVER_ADDR) /* dnsServers */,

                SERVER_ADDR /* dhcpServerIdentifier */, null /* domainName */, false /* metered */);

                SERVER_ADDR /* dhcpServerIdentifier */, null /* domainName */, hostname,

                false /* metered */, MTU);



        ByteArrayOutputStream bos = new ByteArrayOutputStream();

        // BOOTP headers
@@ -1027,12 +1033,22 @@ public class DhcpPacketTest { 
        // Nameserver

        bos.write(new byte[] { (byte) 0x06, (byte) 0x04 });

        bos.write(SERVER_ADDR.getAddress());

        // Hostname

        if (hostname != null) {

            bos.write(new byte[]{(byte) 0x0c, (byte) hostname.length()});

            bos.write(hostname.getBytes(Charset.forName("US-ASCII")));

        }

        // MTU

        bos.write(new byte[] { (byte) 0x1a, (byte) 0x02 });

        bos.write(shortToByteArray(MTU));

        // End options.

        bos.write(0xff);



        final byte[] expected = bos.toByteArray();

        assertTrue((expected.length & 1) == 0);

        if ((bos.size() & 1) != 0) {

            bos.write(0x00);

        }



        final byte[] expected = bos.toByteArray();

        final byte[] actual = new byte[packet.limit()];

        packet.get(actual);

        final String msg = "Expected:\n  " + HexDump.dumpHexString(expected) +
@@ -1042,13 +1058,18 @@ public class DhcpPacketTest { 


    @Test

    public void testOfferPacket() throws Exception {

        checkBuildOfferPacket(3600);

        checkBuildOfferPacket(Integer.MAX_VALUE);

        checkBuildOfferPacket(0x80000000);

        checkBuildOfferPacket(INFINITE_LEASE);

        checkBuildOfferPacket(3600, HOSTNAME);

        checkBuildOfferPacket(Integer.MAX_VALUE, HOSTNAME);

        checkBuildOfferPacket(0x80000000, HOSTNAME);

        checkBuildOfferPacket(INFINITE_LEASE, HOSTNAME);

        checkBuildOfferPacket(3600, null);

    }



    private static byte[] intToByteArray(int val) {

        return ByteBuffer.allocate(4).putInt(val).array();

    }



    private static byte[] shortToByteArray(short val) {

        return ByteBuffer.allocate(2).putShort(val).array();

    }

}

tests/net/java/android/net/dhcp/DhcpServerTest.java

+17 −6
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
package android.net.dhcp;



import static android.net.dhcp.DhcpPacket.DHCP_CLIENT;

import static android.net.dhcp.DhcpPacket.DHCP_HOST_NAME;

import static android.net.dhcp.DhcpPacket.ENCAP_BOOTP;

import static android.net.dhcp.DhcpPacket.INADDR_ANY;

import static android.net.dhcp.DhcpPacket.INADDR_BROADCAST;
@@ -87,6 +88,7 @@ public class DhcpServerTest { 
            Arrays.asList(parseAddr("192.168.0.200"), parseAddr("192.168.0.201")));

    private static final long TEST_LEASE_TIME_SECS = 3600L;

    private static final int TEST_MTU = 1500;

    private static final String TEST_HOSTNAME = "testhostname";



    private static final int TEST_TRANSACTION_ID = 123;

    private static final byte[] TEST_CLIENT_MAC_BYTES = new byte [] { 1, 2, 3, 4, 5, 6 };
@@ -96,7 +98,10 @@ public class DhcpServerTest { 
    private static final long TEST_CLOCK_TIME = 1234L;

    private static final int TEST_LEASE_EXPTIME_SECS = 3600;

    private static final DhcpLease TEST_LEASE = new DhcpLease(null, TEST_CLIENT_MAC,

            TEST_CLIENT_ADDR, TEST_LEASE_EXPTIME_SECS*1000L + TEST_CLOCK_TIME, null /* hostname */);

            TEST_CLIENT_ADDR, TEST_LEASE_EXPTIME_SECS * 1000L + TEST_CLOCK_TIME,

            null /* hostname */);

    private static final DhcpLease TEST_LEASE_WITH_HOSTNAME = new DhcpLease(null, TEST_CLIENT_MAC,

            TEST_CLIENT_ADDR, TEST_LEASE_EXPTIME_SECS * 1000L + TEST_CLOCK_TIME, TEST_HOSTNAME);



    @NonNull @Mock

    private Dependencies mDeps;
@@ -217,15 +222,17 @@ public class DhcpServerTest { 
    public void testRequest_Selecting_Ack() throws Exception {

        when(mRepository.requestLease(isNull() /* clientId */, eq(TEST_CLIENT_MAC),

                eq(INADDR_ANY) /* clientAddr */, eq(INADDR_ANY) /* relayAddr */,

                eq(TEST_CLIENT_ADDR) /* reqAddr */, eq(true) /* sidSet */, isNull() /* hostname */))

                .thenReturn(TEST_LEASE);

                eq(TEST_CLIENT_ADDR) /* reqAddr */, eq(true) /* sidSet */, eq(TEST_HOSTNAME)))

                .thenReturn(TEST_LEASE_WITH_HOSTNAME);



        final DhcpRequestPacket request = makeRequestSelectingPacket();

        request.mHostName = TEST_HOSTNAME;

        request.mRequestedParams = new byte[] { DHCP_HOST_NAME };

        mServer.processPacket(request, DHCP_CLIENT);



        assertResponseSentTo(TEST_CLIENT_ADDR);

        final DhcpAckPacket packet = assertAck(getPacket());

        assertMatchesTestLease(packet);

        assertMatchesTestLease(packet, TEST_HOSTNAME);

    }



    @Test
@@ -270,14 +277,18 @@ public class DhcpServerTest { 
     *  - other request states (init-reboot/renewing/rebinding)

     */



    private void assertMatchesTestLease(@NonNull DhcpPacket packet) {

    private void assertMatchesTestLease(@NonNull DhcpPacket packet, @Nullable String hostname) {

        assertMatchesClient(packet);

        assertFalse(packet.hasExplicitClientId());

        assertEquals(TEST_SERVER_ADDR, packet.mServerIdentifier);

        assertEquals(TEST_CLIENT_ADDR, packet.mYourIp);

        assertNotNull(packet.mLeaseTime);

        assertEquals(TEST_LEASE_EXPTIME_SECS, (int) packet.mLeaseTime);

        assertNull(packet.mHostName);

        assertEquals(hostname, packet.mHostName);

    }



    private void assertMatchesTestLease(@NonNull DhcpPacket packet) {

        assertMatchesTestLease(packet, null);

    }



    private void assertMatchesClient(@NonNull DhcpPacket packet) {