1. Fix a bug in PXE driver that the PXE boot do not restart if a new boot option on the different IP stack is selected.

2. Retrieve the IP information after iSCSI TCPv6 connection established and fill it into iBFT table.
3. Generate a random IAID for each NIC port to require different IPv6 address in PXE driver.
4. Update function EfiMtftp6Configure() and Mtftp6RrqHandleOack() to allocate at most one UdpIo.
5. Fix a typo from “destory” to “destroy” in network code.

Signed-off-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: Ye Ting <ting.ye@intel.com>
Reviewed-by: Ouyang Qian <qian.ouyang@intel.com>

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13859 6f19259b-4bc3-4df7-8a09-765794883524

NetworkPkg/Mtftp6Dxe/Mtftp6Rrq.c

@@ -547,13 +547,15 @@ Mtftp6RrqHandleOack (
         );
 
       Instance->McastPort  = ExtInfo.McastPort;
-      Instance->McastUdpIo = UdpIoCreateIo (
-                               Instance->Service->Controller,
-                               Instance->Service->Image,
-                               Mtftp6RrqConfigMcastUdpIo,
-                               UDP_IO_UDP6_VERSION,
-                               Instance
-                               );
+      if (Instance->McastUdpIo == NULL) {
+        Instance->McastUdpIo = UdpIoCreateIo (
+                                 Instance->Service->Controller,
+                                 Instance->Service->Image,
+                                 Mtftp6RrqConfigMcastUdpIo,
+                                 UDP_IO_UDP6_VERSION,
+                                 Instance
+                                 );
+      }
 
       if (Instance->McastUdpIo == NULL) {
         return EFI_DEVICE_ERROR;