DHCPv6 addr reg: build an IA Address option inside Dhcp6AddrRegInform.

Flag: EXEMPT guarded by an legacy experiment flag
Bug: 293393743
Test: TH
Change-Id: Ia16ba2b5ca9af3810506548085c995eed172b772

staticlibs/device/com/android/net/module/util/dhcp6/Dhcp6AddrRegInformPacket.java

@@ -20,6 +20,9 @@ import static com.android.net.module.util.NetworkStackConstants.DHCP_MAX_LENGTH;
 
 import androidx.annotation.NonNull;
 
+import com.android.net.module.util.structs.IaAddressOption;
+
+import java.net.Inet6Address;
 import java.nio.ByteBuffer;
 
 /**
@@ -29,13 +32,20 @@ import java.nio.ByteBuffer;
  * https://www.rfc-editor.org/rfc/rfc9686.html#section-4.2
  */
 public class Dhcp6AddrRegInformPacket extends Dhcp6Packet {
+    @NonNull
+    public final Inet6Address mIaAddress;
+    public final long mPreferred;
+    public final long mValid;
+
     /**
      * Generates a ADDR-REG-INFORM packet with the specified parameters.
      */
     Dhcp6AddrRegInformPacket(int transId, int elapsedTime, @NonNull final byte[] clientDuid,
-            @NonNull final byte[] iaAddress) {
+            @NonNull final Inet6Address iaAddress, long preferred, long valid) {
         super(transId, elapsedTime, clientDuid, null /* serverDuid */, null /* iapd */);
         mIaAddress = iaAddress;
+        mPreferred = preferred;
+        mValid = valid;
     }
 
     /**
@@ -48,7 +58,9 @@ public class Dhcp6AddrRegInformPacket extends Dhcp6Packet {
 
         addTlv(packet, DHCP6_CLIENT_IDENTIFIER, mClientDuid);
         addTlv(packet, DHCP6_ELAPSED_TIME, (short) (mElapsedTime & 0xFFFF));
-        addTlv(packet, DHCP6_IA_ADDR, mIaAddress);
+        final ByteBuffer iaAddressOption = IaAddressOption.build(
+                (short) IaAddressOption.LENGTH, mIaAddress, mPreferred, mValid);
+        addTlv(packet, iaAddressOption);
 
         packet.flip();
         return packet;

staticlibs/device/com/android/net/module/util/dhcp6/Dhcp6Packet.java

@@ -28,6 +28,9 @@ import com.android.net.module.util.Struct;
 import com.android.net.module.util.structs.IaPdOption;
 import com.android.net.module.util.structs.IaPrefixOption;
 
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
 import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
@@ -88,8 +91,6 @@ public class Dhcp6Packet {
      * DHCPv6 Optional Type: IA Address option.
      */
     public static final byte DHCP6_IA_ADDR = 5;
-    @Nullable
-    protected byte[] mIaAddress;
 
     /**
      * DHCPv6 Optional Type: Option Request Option.
@@ -212,14 +213,6 @@ public class Dhcp6Packet {
         return mServerDuid;
     }
 
-    /**
-     * Returns the IA Address option.
-     */
-    @Nullable
-    public byte[] getIaAddress() {
-        return mIaAddress;
-    }
-
     /**
      * Returns the SOL_MAX_RT option value in milliseconds.
      */
@@ -473,7 +466,9 @@ public class Dhcp6Packet {
     private static Dhcp6Packet decode(@NonNull final ByteBuffer packet) throws ParseException {
         int elapsedTime = 0;
         byte[] iapd = null;
-        byte[] iaAddress = null;
+        Inet6Address iaAddress = null;
+        long preferred = 0;
+        long valid = 0;
         byte[] serverDuid = null;
         byte[] clientDuid = null;
         short statusCode = STATUS_SUCCESS;
@@ -549,10 +544,10 @@ public class Dhcp6Packet {
                         expectedLen = optionLen;
                         final byte[] iaAddressBytes = new byte[16];
                         packet.get(iaAddressBytes, 0 /* offset */, 16);
-                        iaAddress = iaAddressBytes;
-                        // TODO: support parsing preferred and valid lifetime.
-                        packet.getInt(); // preferred lifetime
-                        packet.getInt(); // valid lifetime
+                        // UnknownHostException will be thrown if host address is not determined.
+                        iaAddress = (Inet6Address) InetAddress.getByAddress(iaAddressBytes);
+                        preferred = packet.getInt();
+                        valid = packet.getInt();
                         // IAaddr-options are currently unsupported, skip over them.
                         final int remainingBytesLength = optionLen - 16 - 8;
                         if (remainingBytesLength > 0) {
@@ -578,7 +573,7 @@ public class Dhcp6Packet {
                             "Invalid length " + optionLen + " for option " + optionType
                                     + ", expected " + expectedLen);
                 }
-            } catch (BufferUnderflowException e) {
+            } catch (BufferUnderflowException | UnknownHostException e) {
                 throw new ParseException(e.getMessage());
             }
         }
@@ -609,8 +604,11 @@ public class Dhcp6Packet {
                 newPacket = new Dhcp6RebindPacket(transId, elapsedTime, clientDuid, iapd);
                 break;
             case DHCP6_MESSAGE_TYPE_ADDR_REG_INFORM:
+                if (iaAddress == null) {
+                    throw new ParseException("IA Address option isn't present in ADDR_REG_INFORM");
+                }
                 newPacket = new Dhcp6AddrRegInformPacket(transId, elapsedTime, clientDuid,
-                        iaAddress);
+                        iaAddress, preferred, valid);
                 break;
             default:
                 throw new ParseException("Unimplemented DHCP6 message type %d" + messageType);
@@ -728,6 +726,13 @@ public class Dhcp6Packet {
         buf.putShort((short) 0);
     }
 
+    /**
+     * Adds an optional parameter containing a complete option (type, length, value).
+     */
+    protected static void addTlv(ByteBuffer buf, ByteBuffer option) {
+        buf.put(option);
+    }
+
     /**
      * Builds a DHCPv6 SOLICIT packet from the required specified parameters.
      */