Set clientId when parsing an explicit DHCP_CLIENT_IDENTIFIER option.

Bug: 130741856
Test: atest NetworkStackTests TetheringTests
Test: manually turn on the hotspot and verify the downstream device
      can attach to the upstream hotspot, then turn it off, repeat
      multiple times.
Merged-In: I9da5fec47a74de36869e795fa9b1d7170d2f91c9
Change-Id: I9da5fec47a74de36869e795fa9b1d7170d2f91c9

2 files changed, 37 insertions, 2 deletions

diff --git a/src/android/net/dhcp/DhcpPacket.java b/src/android/net/dhcp/DhcpPacket.java
index 852719e..a4dbda1 100644
--- a/src/android/net/dhcp/DhcpPacket.java
+++ b/src/android/net/dhcp/DhcpPacket.java
@@ -1182,8 +1182,8 @@ public abstract class DhcpPacket {
                             vendorId = readAsciiString(packet, optionLen, true);
                             break;
                         case DHCP_CLIENT_IDENTIFIER: { // Client identifier
-                            byte[] id = new byte[optionLen];
-                            packet.get(id);
+                            clientId = new byte[optionLen];
+                            packet.get(clientId);
                             expectedLen = optionLen;
                         } break;
                         case DHCP_VENDOR_INFO:
diff --git a/tests/unit/src/android/net/dhcp/DhcpPacketTest.java b/tests/unit/src/android/net/dhcp/DhcpPacketTest.java
index 6ce1fdf..c565238 100644
--- a/tests/unit/src/android/net/dhcp/DhcpPacketTest.java
+++ b/tests/unit/src/android/net/dhcp/DhcpPacketTest.java
@@ -728,6 +728,41 @@ public class DhcpPacketTest {
     }
 
     @Test
+    public void testExplicitClientId() throws Exception {
+        final byte[] clientId = new byte[] {
+                0x01 /* CLIENT_ID_ETH */, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06 };
+
+        // CHECKSTYLE:OFF Generated code
+        final byte[] packet = HexDump.hexStringToByteArray(
+                // IP header.
+                "450001518d0600004011144dc0a82b01c0a82bf7" +
+                // UDP header
+                "00430044013d9ac7" +
+                // BOOTP header
+                "02010600dfc23d1f0002000000000000c0a82bf7c0a82b0100000000" +
+                // MAC address.
+                "30766ff2a90c00000000000000000000" +
+                // Server name ("dhcp.android.com" plus invalid "AAAA" after null terminator).
+                "646863702e616e64726f69642e636f6d00000000000000000000000000000000" +
+                "0000000000004141414100000000000000000000000000000000000000000000" +
+                // File.
+                "0000000000000000000000000000000000000000000000000000000000000000" +
+                "0000000000000000000000000000000000000000000000000000000000000000" +
+                "0000000000000000000000000000000000000000000000000000000000000000" +
+                "0000000000000000000000000000000000000000000000000000000000000000" +
+                // Options
+                "638253633501013d0701010203040506390205dc3c0e616e64726f69642d6468" +
+                "63702d52370a0103060f1a1c333a3b2bff00");
+        // CHECKSTYLE:ON Generated code
+
+        final DhcpPacket discoverPacket = DhcpPacket.decodeFullPacket(packet,
+                packet.length, ENCAP_L3);
+        assertTrue(discoverPacket instanceof DhcpDiscoverPacket);
+        assertTrue(discoverPacket.hasExplicitClientId());
+        assertTrue(Arrays.equals(discoverPacket.mClientId, clientId));
+    }
+
+    @Test
     public void testBadHwaddrLength() throws Exception {
         // CHECKSTYLE:OFF Generated code
         final ByteBuffer packet = ByteBuffer.wrap(HexDump.hexStringToByteArray(