MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Driver.c

   1 /** @file
   2
   3 Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
   4 This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12 **/
  13
  14 #include "Dhcp4Impl.h"
  15 #include "Dhcp4Driver.h"
  16
  17 EFI_DRIVER_BINDING_PROTOCOL gDhcp4DriverBinding = {
  18   Dhcp4DriverBindingSupported,
  19   Dhcp4DriverBindingStart,
  20   Dhcp4DriverBindingStop,
  21   0xa,
  22   NULL,
  23   NULL
  24 };
  25
  26 EFI_SERVICE_BINDING_PROTOCOL mDhcp4ServiceBindingTemplate = {
  27   Dhcp4ServiceBindingCreateChild,
  28   Dhcp4ServiceBindingDestroyChild
  29 };
  30
  31 /**
  32   This is the declaration of an EFI image entry point. This entry point is
  33   the same for UEFI Applications, UEFI OS Loaders, and UEFI Drivers including
  34   both device drivers and bus drivers.
  35
  36   Entry point of the DHCP driver to install various protocols.
  37
  38   @param[in]  ImageHandle           The firmware allocated handle for the UEFI image.
  39   @param[in]  SystemTable           A pointer to the EFI System Table.
  40
  41   @retval EFI_SUCCESS           The operation completed successfully.
  42   @retval EFI_OUT_OF_RESOURCES  The request could not be completed due to a lack of resources.
  43
  44 **/
  45 EFI_STATUS
  46 EFIAPI
  47 Dhcp4DriverEntryPoint (
  48   IN EFI_HANDLE             ImageHandle,
  49   IN EFI_SYSTEM_TABLE       *SystemTable
  50   )
  51 {
  52   return EfiLibInstallDriverBindingComponentName2 (
  53            ImageHandle,
  54            SystemTable,
  55            &gDhcp4DriverBinding,
  56            ImageHandle,
  57            &gDhcp4ComponentName,
  58            &gDhcp4ComponentName2
  59            );
  60 }
  61
  62
  63 /**
  64   Test to see if this driver supports ControllerHandle. This service
  65   is called by the EFI boot service ConnectController(). In
  66   order to make drivers as small as possible, there are a few calling
  67   restrictions for this service. ConnectController() must
  68   follow these calling restrictions. If any other agent wishes to call
  69   Supported() it must also follow these calling restrictions.
  70
  71   @param[in]  This                Protocol instance pointer.
  72   @param[in]  ControllerHandle    Handle of device to test
  73   @param[in]  RemainingDevicePath Optional parameter use to pick a specific child
  74                                   device to start.
  75
  76   @retval EFI_SUCCESS         This driver supports this device
  77   @retval EFI_ALREADY_STARTED This driver is already running on this device
  78   @retval other               This driver does not support this device
  79
  80 **/
  81 EFI_STATUS
  82 EFIAPI
  83 Dhcp4DriverBindingSupported (
  84   IN EFI_DRIVER_BINDING_PROTOCOL  *This,
  85   IN EFI_HANDLE                   ControllerHandle,
  86   IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath OPTIONAL
  87   )
  88 {
  89   EFI_STATUS  Status;
  90
  91   Status = gBS->OpenProtocol (
  92                   ControllerHandle,
  93                   &gEfiUdp4ServiceBindingProtocolGuid,
  94                   NULL,
  95                   This->DriverBindingHandle,
  96                   ControllerHandle,
  97                   EFI_OPEN_PROTOCOL_TEST_PROTOCOL
  98                   );
  99
 100   return Status;
 101 }
 102
 103
 104
 105 /**
 106   Configure the default UDP child to receive all the DHCP traffics
 107   on this network interface.
 108
 109   @param[in]  UdpIo                  The UDP IO to configure
 110   @param[in]  Context                The context to the function
 111
 112   @retval EFI_SUCCESS            The UDP IO is successfully configured.
 113   @retval Others                 Failed to configure the UDP child.
 114
 115 **/
 116 EFI_STATUS
 117 EFIAPI
 118 DhcpConfigUdpIo (
 119   IN UDP_IO                 *UdpIo,
 120   IN VOID                   *Context
 121   )
 122 {
 123   EFI_UDP4_CONFIG_DATA      UdpConfigData;
 124
 125   UdpConfigData.AcceptBroadcast           = TRUE;
 126   UdpConfigData.AcceptPromiscuous         = FALSE;
 127   UdpConfigData.AcceptAnyPort             = FALSE;
 128   UdpConfigData.AllowDuplicatePort        = TRUE;
 129   UdpConfigData.TypeOfService             = 0;
 130   UdpConfigData.TimeToLive                = 64;
 131   UdpConfigData.DoNotFragment             = FALSE;
 132   UdpConfigData.ReceiveTimeout            = 0;
 133   UdpConfigData.TransmitTimeout           = 0;
 134
 135   UdpConfigData.UseDefaultAddress         = FALSE;
 136   UdpConfigData.StationPort               = DHCP_CLIENT_PORT;
 137   UdpConfigData.RemotePort                = DHCP_SERVER_PORT;
 138
 139   ZeroMem (&UdpConfigData.StationAddress, sizeof (EFI_IPv4_ADDRESS));
 140   ZeroMem (&UdpConfigData.SubnetMask, sizeof (EFI_IPv4_ADDRESS));
 141   ZeroMem (&UdpConfigData.RemoteAddress, sizeof (EFI_IPv4_ADDRESS));
 142
 143   return UdpIo->Protocol.Udp4->Configure (UdpIo->Protocol.Udp4, &UdpConfigData);;
 144 }
 145
 146
 147
 148 /**
 149   Destroy the DHCP service. The Dhcp4 service may be partly initialized,
 150   or partly destroyed. If a resource is destroyed, it is marked as so in
 151   case the destroy failed and being called again later.
 152
 153   @param[in]  DhcpSb                 The DHCP service instance to destroy.
 154
 155   @retval EFI_SUCCESS            Always return success.
 156
 157 **/
 158 EFI_STATUS
 159 Dhcp4CloseService (
 160   IN DHCP_SERVICE           *DhcpSb
 161   )
 162 {
 163   DhcpCleanLease (DhcpSb);
 164
 165   if (DhcpSb->UdpIo != NULL) {
 166     UdpIoFreeIo (DhcpSb->UdpIo);
 167     DhcpSb->UdpIo = NULL;
 168   }
 169
 170   if (DhcpSb->Timer != NULL) {
 171     gBS->SetTimer (DhcpSb->Timer, TimerCancel, 0);
 172     gBS->CloseEvent (DhcpSb->Timer);
 173
 174     DhcpSb->Timer = NULL;
 175   }
 176
 177   return EFI_SUCCESS;
 178 }
 179
 180
 181
 182 /**
 183   Create a new DHCP service binding instance for the controller.
 184
 185   @param[in]  Controller             The controller to install DHCP service binding
 186                                      protocol onto
 187   @param[in]  ImageHandle            The driver's image handle
 188   @param[out] Service                The variable to receive the created DHCP service
 189                                      instance.
 190
 191   @retval EFI_OUT_OF_RESOURCES   Failed to allocate resource .
 192   @retval EFI_SUCCESS            The DHCP service instance is created.
 193   @retval other                  Other error occurs.
 194
 195 **/
 196 EFI_STATUS
 197 Dhcp4CreateService (
 198   IN  EFI_HANDLE            Controller,
 199   IN  EFI_HANDLE            ImageHandle,
 200   OUT DHCP_SERVICE          **Service
 201   )
 202 {
 203   DHCP_SERVICE              *DhcpSb;
 204   EFI_STATUS                Status;
 205
 206   *Service  = NULL;
 207   DhcpSb    = AllocateZeroPool (sizeof (DHCP_SERVICE));
 208
 209   if (DhcpSb == NULL) {
 210     return EFI_OUT_OF_RESOURCES;
 211   }
 212
 213   DhcpSb->Signature       = DHCP_SERVICE_SIGNATURE;
 214   DhcpSb->ServiceState    = DHCP_UNCONFIGED;
 215   DhcpSb->Controller      = Controller;
 216   DhcpSb->Image           = ImageHandle;
 217   InitializeListHead (&DhcpSb->Children);
 218   DhcpSb->DhcpState       = Dhcp4Stopped;
 219   DhcpSb->Xid             = NET_RANDOM (NetRandomInitSeed ());
 220   CopyMem (
 221     &DhcpSb->ServiceBinding,
 222     &mDhcp4ServiceBindingTemplate,
 223     sizeof (EFI_SERVICE_BINDING_PROTOCOL)
 224     );
 225   //
 226   // Create various resources, UdpIo, Timer, and get Mac address
 227   //
 228   Status = gBS->CreateEvent (
 229                   EVT_NOTIFY_SIGNAL | EVT_TIMER,
 230                   TPL_CALLBACK,
 231                   DhcpOnTimerTick,
 232                   DhcpSb,
 233                   &DhcpSb->Timer
 234                   );
 235
 236   if (EFI_ERROR (Status)) {
 237     goto ON_ERROR;
 238   }
 239
 240   DhcpSb->UdpIo = UdpIoCreateIo (
 241                     Controller,
 242                     ImageHandle,
 243                     DhcpConfigUdpIo,
 244                     UDP_IO_UDP4_VERSION,
 245                     NULL
 246                     );
 247
 248   if (DhcpSb->UdpIo == NULL) {
 249     Status = EFI_OUT_OF_RESOURCES;
 250     goto ON_ERROR;
 251   }
 252
 253   DhcpSb->HwLen  = (UINT8) DhcpSb->UdpIo->SnpMode.HwAddressSize;
 254   DhcpSb->HwType = DhcpSb->UdpIo->SnpMode.IfType;
 255   CopyMem (&DhcpSb->Mac, &DhcpSb->UdpIo->SnpMode.CurrentAddress, sizeof (DhcpSb->Mac));
 256
 257   *Service       = DhcpSb;
 258   return EFI_SUCCESS;
 259
 260 ON_ERROR:
 261   Dhcp4CloseService (DhcpSb);
 262   FreePool (DhcpSb);
 263
 264   return Status;
 265 }
 266
 267
 268 /**
 269   Start this driver on ControllerHandle. This service is called by the
 270   EFI boot service ConnectController(). In order to make
 271   drivers as small as possible, there are a few calling restrictions for
 272   this service. ConnectController() must follow these
 273   calling restrictions. If any other agent wishes to call Start() it
 274   must also follow these calling restrictions.
 275
 276   @param[in]  This                 Protocol instance pointer.
 277   @param[in]  ControllerHandle     Handle of device to bind driver to
 278   @param[in]  RemainingDevicePath  Optional parameter use to pick a specific child
 279                                    device to start.
 280
 281   @retval EFI_SUCCESS          This driver is added to ControllerHandle
 282   @retval EFI_ALREADY_STARTED  This driver is already running on ControllerHandle
 283   @retval other                This driver does not support this device
 284
 285 **/
 286 EFI_STATUS
 287 EFIAPI
 288 Dhcp4DriverBindingStart (
 289   IN EFI_DRIVER_BINDING_PROTOCOL  *This,
 290   IN EFI_HANDLE                   ControllerHandle,
 291   IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath OPTIONAL
 292   )
 293 {
 294   DHCP_SERVICE              *DhcpSb;
 295   EFI_STATUS                Status;
 296
 297   //
 298   // First: test for the DHCP4 Protocol
 299   //
 300   Status = gBS->OpenProtocol (
 301                   ControllerHandle,
 302                   &gEfiDhcp4ServiceBindingProtocolGuid,
 303                   NULL,
 304                   This->DriverBindingHandle,
 305                   ControllerHandle,
 306                   EFI_OPEN_PROTOCOL_TEST_PROTOCOL
 307                   );
 308
 309   if (Status == EFI_SUCCESS) {
 310     return EFI_ALREADY_STARTED;
 311   }
 312
 313   Status = Dhcp4CreateService (ControllerHandle, This->DriverBindingHandle, &DhcpSb);
 314
 315   if (EFI_ERROR (Status)) {
 316     return Status;
 317   }
 318   ASSERT (DhcpSb != NULL);
 319
 320   //
 321   // Start the receiving
 322   //
 323   Status = UdpIoRecvDatagram (DhcpSb->UdpIo, DhcpInput, DhcpSb, 0);
 324
 325   if (EFI_ERROR (Status)) {
 326     goto ON_ERROR;
 327   }
 328   Status = gBS->SetTimer (DhcpSb->Timer, TimerPeriodic, TICKS_PER_SECOND);
 329
 330   if (EFI_ERROR (Status)) {
 331     goto ON_ERROR;
 332   }
 333
 334   //
 335   // Install the Dhcp4ServiceBinding Protocol onto ControlerHandle
 336   //
 337   Status = gBS->InstallMultipleProtocolInterfaces (
 338                   &ControllerHandle,
 339                   &gEfiDhcp4ServiceBindingProtocolGuid,
 340                   &DhcpSb->ServiceBinding,
 341                   NULL
 342                   );
 343
 344   if (EFI_ERROR (Status)) {
 345     goto ON_ERROR;
 346   }
 347
 348   return Status;
 349
 350 ON_ERROR:
 351   Dhcp4CloseService (DhcpSb);
 352   FreePool (DhcpSb);
 353   return Status;
 354 }
 355
 356 /**
 357   Callback function which provided by user to remove one node in NetDestroyLinkList process.
 358
 359   @param[in]    Entry           The entry to be removed.
 360   @param[in]    Context         Pointer to the callback context corresponds to the Context in NetDestroyLinkList.
 361
 362   @retval EFI_SUCCESS           The entry has been removed successfully.
 363   @retval Others                Fail to remove the entry.
 364
 365 **/
 366 EFI_STATUS
 367 Dhcp4DestroyChildEntry (
 368   IN LIST_ENTRY         *Entry,
 369   IN VOID               *Context
 370 )
 371 {
 372   DHCP_PROTOCOL                    *Instance;
 373   EFI_SERVICE_BINDING_PROTOCOL     *ServiceBinding;
 374
 375   if (Entry == NULL || Context == NULL) {
 376     return EFI_INVALID_PARAMETER;
 377   }
 378
 379   Instance = NET_LIST_USER_STRUCT_S (Entry, DHCP_PROTOCOL, Link, DHCP_PROTOCOL_SIGNATURE);
 380   ServiceBinding = (EFI_SERVICE_BINDING_PROTOCOL *) Context;
 381
 382   return ServiceBinding->DestroyChild (ServiceBinding, Instance->Handle);
 383 }
 384
 385
 386 /**
 387   Stop this driver on ControllerHandle. This service is called by the
 388   EFI boot service DisconnectController(). In order to
 389   make drivers as small as possible, there are a few calling
 390   restrictions for this service. DisconnectController()
 391   must follow these calling restrictions. If any other agent wishes
 392   to call Stop() it must also follow these calling restrictions.
 393
 394   @param[in]  This              Protocol instance pointer.
 395   @param[in]  ControllerHandle  Handle of device to stop driver on
 396   @param[in]  NumberOfChildren  Number of Handles in ChildHandleBuffer. If number of
 397                                 children is zero stop the entire bus driver.
 398   @param[in]  ChildHandleBuffer List of Child Handles to Stop.
 399
 400   @retval EFI_SUCCESS       This driver is removed ControllerHandle
 401   @retval other             This driver was not removed from this device
 402
 403 **/
 404 EFI_STATUS
 405 EFIAPI
 406 Dhcp4DriverBindingStop (
 407   IN  EFI_DRIVER_BINDING_PROTOCOL  *This,
 408   IN  EFI_HANDLE                   ControllerHandle,
 409   IN  UINTN                        NumberOfChildren,
 410   IN  EFI_HANDLE                   *ChildHandleBuffer
 411   )
 412 {
 413   EFI_SERVICE_BINDING_PROTOCOL  *ServiceBinding;
 414   DHCP_SERVICE                  *DhcpSb;
 415   EFI_HANDLE                    NicHandle;
 416   EFI_STATUS                    Status;
 417   LIST_ENTRY                    *List;
 418   UINTN                         ListLength;
 419
 420   //
 421   // DHCP driver opens UDP child, So, the ControllerHandle is the
 422   // UDP child handle. locate the Nic handle first.
 423   //
 424   NicHandle = NetLibGetNicHandle (ControllerHandle, &gEfiUdp4ProtocolGuid);
 425
 426   if (NicHandle == NULL) {
 427     return EFI_SUCCESS;
 428   }
 429
 430    Status = gBS->OpenProtocol (
 431                   NicHandle,
 432                   &gEfiDhcp4ServiceBindingProtocolGuid,
 433                   (VOID **) &ServiceBinding,
 434                   This->DriverBindingHandle,
 435                   NicHandle,
 436                   EFI_OPEN_PROTOCOL_GET_PROTOCOL
 437                   );
 438
 439   if (EFI_ERROR (Status)) {
 440     return EFI_DEVICE_ERROR;
 441   }
 442
 443   DhcpSb = DHCP_SERVICE_FROM_THIS (ServiceBinding);
 444   if (!IsListEmpty (&DhcpSb->Children)) {
 445     //
 446     // Destroy all the children instances before destory the service.
 447     //
 448     List = &DhcpSb->Children;
 449     Status = NetDestroyLinkList (
 450                List,
 451                Dhcp4DestroyChildEntry,
 452                ServiceBinding,
 453                &ListLength
 454                );
 455     if (EFI_ERROR (Status) || ListLength != 0) {
 456       Status = EFI_DEVICE_ERROR;
 457     }
 458   }
 459
 460   if (NumberOfChildren == 0 && !IsListEmpty (&DhcpSb->Children)) {
 461     Status = EFI_DEVICE_ERROR;
 462   }
 463
 464   if (NumberOfChildren == 0 && IsListEmpty (&DhcpSb->Children)) {
 465     //
 466     // Destroy the service itself if no child instance left.
 467     //
 468     DhcpSb->ServiceState = DHCP_DESTROY;
 469
 470     gBS->UninstallProtocolInterface (
 471            NicHandle,
 472            &gEfiDhcp4ServiceBindingProtocolGuid,
 473            ServiceBinding
 474            );
 475
 476     Dhcp4CloseService (DhcpSb);
 477
 478     if (gDhcpControllerNameTable != NULL) {
 479       FreeUnicodeStringTable (gDhcpControllerNameTable);
 480       gDhcpControllerNameTable = NULL;
 481     }
 482     FreePool (DhcpSb);
 483
 484     Status = EFI_SUCCESS;
 485   }
 486
 487   return Status;
 488 }
 489
 490
 491 /**
 492   Initialize a new DHCP instance.
 493
 494   @param  DhcpSb                 The dhcp service instance
 495   @param  Instance               The dhcp instance to initialize
 496
 497 **/
 498 VOID
 499 DhcpInitProtocol (
 500   IN     DHCP_SERVICE           *DhcpSb,
 501   IN OUT DHCP_PROTOCOL          *Instance
 502   )
 503 {
 504   Instance->Signature         = DHCP_PROTOCOL_SIGNATURE;
 505   CopyMem (&Instance->Dhcp4Protocol, &mDhcp4ProtocolTemplate, sizeof (Instance->Dhcp4Protocol));
 506   InitializeListHead (&Instance->Link);
 507   Instance->Handle            = NULL;
 508   Instance->Service           = DhcpSb;
 509   Instance->InDestroy         = FALSE;
 510   Instance->CompletionEvent   = NULL;
 511   Instance->RenewRebindEvent  = NULL;
 512   Instance->Token             = NULL;
 513   Instance->UdpIo             = NULL;
 514   Instance->ElaspedTime       = 0;
 515   NetbufQueInit (&Instance->ResponseQueue);
 516 }
 517
 518
 519 /**
 520   Creates a child handle and installs a protocol.
 521
 522   The CreateChild() function installs a protocol on ChildHandle.
 523   If ChildHandle is a pointer to NULL, then a new handle is created and returned in ChildHandle.
 524   If ChildHandle is not a pointer to NULL, then the protocol installs on the existing ChildHandle.
 525
 526   @param  This        Pointer to the EFI_SERVICE_BINDING_PROTOCOL instance.
 527   @param  ChildHandle Pointer to the handle of the child to create. If it is NULL,
 528                       then a new handle is created. If it is a pointer to an existing UEFI handle,
 529                       then the protocol is added to the existing UEFI handle.
 530
 531   @retval EFI_SUCCES            The protocol was added to ChildHandle.
 532   @retval EFI_INVALID_PARAMETER ChildHandle is NULL.
 533   @retval EFI_OUT_OF_RESOURCES  There are not enough resources availabe to create
 534                                 the child
 535   @retval other                 The child handle was not created
 536
 537 **/
 538 EFI_STATUS
 539 EFIAPI
 540 Dhcp4ServiceBindingCreateChild (
 541   IN EFI_SERVICE_BINDING_PROTOCOL  *This,
 542   IN EFI_HANDLE                    *ChildHandle
 543   )
 544 {
 545   DHCP_SERVICE              *DhcpSb;
 546   DHCP_PROTOCOL             *Instance;
 547   EFI_STATUS                Status;
 548   EFI_TPL                   OldTpl;
 549   VOID                      *Udp4;
 550
 551   if ((This == NULL) || (ChildHandle == NULL)) {
 552     return EFI_INVALID_PARAMETER;
 553   }
 554
 555   Instance = AllocatePool (sizeof (*Instance));
 556
 557   if (Instance == NULL) {
 558     return EFI_OUT_OF_RESOURCES;
 559   }
 560
 561   DhcpSb = DHCP_SERVICE_FROM_THIS (This);
 562   DhcpInitProtocol (DhcpSb, Instance);
 563
 564   //
 565   // Install DHCP4 onto ChildHandle
 566   //
 567   Status = gBS->InstallMultipleProtocolInterfaces (
 568                   ChildHandle,
 569                   &gEfiDhcp4ProtocolGuid,
 570                   &Instance->Dhcp4Protocol,
 571                   NULL
 572                   );
 573
 574   if (EFI_ERROR (Status)) {
 575     FreePool (Instance);
 576     return Status;
 577   }
 578
 579   Instance->Handle  = *ChildHandle;
 580
 581   //
 582   // Open the Udp4 protocol BY_CHILD.
 583   //
 584   Status = gBS->OpenProtocol (
 585                   DhcpSb->UdpIo->UdpHandle,
 586                   &gEfiUdp4ProtocolGuid,
 587                   (VOID **) &Udp4,
 588                   gDhcp4DriverBinding.DriverBindingHandle,
 589                   Instance->Handle,
 590                   EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER
 591                   );
 592   if (EFI_ERROR (Status)) {
 593     gBS->UninstallMultipleProtocolInterfaces (
 594            Instance->Handle,
 595            &gEfiDhcp4ProtocolGuid,
 596            &Instance->Dhcp4Protocol,
 597            NULL
 598            );
 599
 600     FreePool (Instance);
 601     return Status;
 602   }
 603
 604   OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
 605
 606   InsertTailList (&DhcpSb->Children, &Instance->Link);
 607   DhcpSb->NumChildren++;
 608
 609   gBS->RestoreTPL (OldTpl);
 610
 611   return EFI_SUCCESS;
 612 }
 613
 614
 615 /**
 616   Destroys a child handle with a protocol installed on it.
 617
 618   The DestroyChild() function does the opposite of CreateChild(). It removes a protocol
 619   that was installed by CreateChild() from ChildHandle. If the removed protocol is the
 620   last protocol on ChildHandle, then ChildHandle is destroyed.
 621
 622   @param  This        Pointer to the EFI_SERVICE_BINDING_PROTOCOL instance.
 623   @param  ChildHandle Handle of the child to destroy
 624
 625   @retval EFI_SUCCES            The protocol was removed from ChildHandle.
 626   @retval EFI_UNSUPPORTED       ChildHandle does not support the protocol that is being removed.
 627   @retval EFI_INVALID_PARAMETER Child handle is NULL.
 628   @retval EFI_ACCESS_DENIED     The protocol could not be removed from the ChildHandle
 629                                 because its services are being used.
 630   @retval other                 The child handle was not destroyed
 631
 632 **/
 633 EFI_STATUS
 634 EFIAPI
 635 Dhcp4ServiceBindingDestroyChild (
 636   IN EFI_SERVICE_BINDING_PROTOCOL  *This,
 637   IN EFI_HANDLE                    ChildHandle
 638   )
 639 {
 640   DHCP_SERVICE              *DhcpSb;
 641   DHCP_PROTOCOL             *Instance;
 642   EFI_DHCP4_PROTOCOL        *Dhcp;
 643   EFI_TPL                   OldTpl;
 644   EFI_STATUS                Status;
 645
 646   if ((This == NULL) || (ChildHandle == NULL)) {
 647     return EFI_INVALID_PARAMETER;
 648   }
 649
 650   //
 651   // Retrieve the private context data structures
 652   //
 653   Status = gBS->OpenProtocol (
 654                   ChildHandle,
 655                   &gEfiDhcp4ProtocolGuid,
 656                   (VOID **) &Dhcp,
 657                   gDhcp4DriverBinding.DriverBindingHandle,
 658                   ChildHandle,
 659                   EFI_OPEN_PROTOCOL_GET_PROTOCOL
 660                   );
 661
 662   if (EFI_ERROR (Status)) {
 663     return EFI_UNSUPPORTED;
 664   }
 665
 666   Instance  = DHCP_INSTANCE_FROM_THIS (Dhcp);
 667   DhcpSb    = DHCP_SERVICE_FROM_THIS (This);
 668
 669   if (Instance->Service != DhcpSb) {
 670     return EFI_INVALID_PARAMETER;
 671   }
 672
 673   //
 674   // A child can be destroyed more than once. For example,
 675   // Dhcp4DriverBindingStop will destroy all of its children.
 676   // when caller driver is being stopped, it will destroy the
 677   // dhcp child it opens.
 678   //
 679   if (Instance->InDestroy) {
 680     return EFI_SUCCESS;
 681   }
 682
 683   OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
 684   Instance->InDestroy = TRUE;
 685
 686   //
 687   // Close the Udp4 protocol.
 688   //
 689   gBS->CloseProtocol (
 690          DhcpSb->UdpIo->UdpHandle,
 691          &gEfiUdp4ProtocolGuid,
 692          gDhcp4DriverBinding.DriverBindingHandle,
 693          ChildHandle
 694          );
 695
 696   //
 697   // Uninstall the DHCP4 protocol first to enable a top down destruction.
 698   //
 699   gBS->RestoreTPL (OldTpl);
 700   Status = gBS->UninstallProtocolInterface (
 701                   ChildHandle,
 702                   &gEfiDhcp4ProtocolGuid,
 703                   Dhcp
 704                   );
 705   OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
 706   if (EFI_ERROR (Status)) {
 707     Instance->InDestroy = FALSE;
 708
 709     gBS->RestoreTPL (OldTpl);
 710     return Status;
 711   }
 712
 713   if (DhcpSb->ActiveChild == Instance) {
 714     DhcpYieldControl (DhcpSb);
 715   }
 716
 717   RemoveEntryList (&Instance->Link);
 718   DhcpSb->NumChildren--;
 719
 720   gBS->RestoreTPL (OldTpl);
 721
 722   FreePool (Instance);
 723   return EFI_SUCCESS;
 724 }