Provide RRO configuration to send DHCP client hostname option.

Add a configurable option in the RRO which controls whether or not to
send the hostname set in the Settings->About phone->Device name. The
option in RRO is false by default, that means DHCP Request still not
include any hostname by default. Once the option is overlaid and enabled,
the device name after transliteration will be wrote into hostname option.

Bug: 131783527
Test: atest NetworkStackTests NetworkStackIntegrationTests
Test: manual test, create empty APK to overlay the RRO configuration.

Change-Id: I9af0b0d9e7bb526d3a3c1003bb99d0a3d69b1e9e

1 files changed, 29 insertions, 4 deletions

diff --git a/src/android/net/dhcp/DhcpClient.java b/src/android/net/dhcp/DhcpClient.java
index 982d8ce..b1df996 100644
--- a/src/android/net/dhcp/DhcpClient.java
+++ b/src/android/net/dhcp/DhcpClient.java
@@ -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;
@@ -306,6 +308,8 @@ 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;
@@ -350,6 +354,22 @@ public class DhcpClient extends StateMachine {
         }
 
         /**
+         * 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.
          */
         public NetworkStackIpMemoryStore getIpMemoryStore() {
@@ -450,6 +470,11 @@ 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() {
@@ -641,7 +666,7 @@ 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);
     }
 
@@ -655,7 +680,7 @@ 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() +
@@ -744,7 +769,7 @@ 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 {
@@ -1259,7 +1284,7 @@ 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();