Add SafetyNet logging to DHCP packet parsing

Test: unit test passes
Bug: 31850211
Change-Id: I47f9db1f2c50ccd4fc90b80a9ffc1e9e43078f5f
(cherry picked from commit a0289894718c230c746f7e85207d30fee431dab8)

services/net/java/android/net/dhcp/DhcpClient.java

diff --git a/services/net/java/android/net/dhcp/DhcpClient.java b/services/net/java/android/net/dhcp/DhcpClient.java
index ffbea9f..8dd05b1 100644
--- a/services/net/java/android/net/dhcp/DhcpClient.java
+++ b/services/net/java/android/net/dhcp/DhcpClient.java
@@ -40,6 +40,7 @@
 import android.system.ErrnoException;
 import android.system.Os;
 import android.system.PacketSocketAddress;
+import android.util.EventLog;
 import android.util.Log;
 import android.util.SparseArray;
 import android.util.TimeUtils;
@@ -369,6 +370,13 @@
                     if (PACKET_DBG) {
                         Log.d(TAG, HexDump.dumpHexString(mPacket, 0, length));
                     }
+                    if (e.errorCode == DhcpErrorEvent.DHCP_NO_COOKIE) {
+                        int snetTagId = 0x534e4554;
+                        String bugId = "31850211";
+                        int uid = -1;
+                        String data = DhcpPacket.ParseException.class.getName();
+                        EventLog.writeEvent(snetTagId, bugId, uid, data);
+                    }
                     logError(e.errorCode);
                 }
             }