MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Io.c

   1 /** @file
   2
   3 Copyright (c) 2006 - 2007, Intel Corporation
   4 All rights reserved. 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 Module Name:
  13
  14   Dhcp4Io.c
  15
  16 Abstract:
  17
  18   EFI DHCP protocol implementation
  19
  20
  21 **/
  22
  23
  24 #include "Dhcp4Impl.h"
  25
  26 UINT32  mDhcp4DefaultTimeout[4] = { 4, 8, 16, 32 };
  27
  28
  29 /**
  30   Send an initial DISCOVER or REQUEST message according to the
  31   DHCP service's current state.
  32
  33   @param  DhcpSb                The DHCP service instance
  34
  35   @retval EFI_SUCCESS           The request has been sent
  36
  37 **/
  38 EFI_STATUS
  39 DhcpInitRequest (
  40   IN DHCP_SERVICE           *DhcpSb
  41   )
  42 {
  43   EFI_STATUS                Status;
  44
  45   ASSERT ((DhcpSb->DhcpState == Dhcp4Init) || (DhcpSb->DhcpState == Dhcp4InitReboot));
  46
  47   if (DhcpSb->DhcpState == Dhcp4Init) {
  48     DhcpSetState (DhcpSb, Dhcp4Selecting, FALSE);
  49     Status = DhcpSendMessage (DhcpSb, NULL, NULL, DHCP_MSG_DISCOVER, NULL);
  50
  51     if (EFI_ERROR (Status)) {
  52       DhcpSb->DhcpState = Dhcp4Init;
  53       return Status;
  54     }
  55   } else {
  56     DhcpSetState (DhcpSb, Dhcp4Rebooting, FALSE);
  57     Status = DhcpSendMessage (DhcpSb, NULL, NULL, DHCP_MSG_REQUEST, NULL);
  58
  59     if (EFI_ERROR (Status)) {
  60       DhcpSb->DhcpState = Dhcp4InitReboot;
  61       return Status;
  62     }
  63   }
  64
  65   return EFI_SUCCESS;
  66 }
  67
  68
  69 /**
  70   Call user provided callback function, and return the value the
  71   function returns. If the user doesn't provide a callback, a
  72   proper return value is selected to let the caller continue the
  73   normal process.
  74
  75   @param  DhcpSb                The DHCP service instance
  76   @param  Event                 The event as defined in the spec
  77   @param  Packet                The current packet trigger the event
  78   @param  NewPacket             The user's return new packet
  79
  80   @retval EFI_NOT_READY         Direct the caller to continue collecting the offer.
  81   @retval EFI_SUCCESS           The user function returns success.
  82   @retval EFI_ABORTED           The user function ask it to abort.
  83
  84 **/
  85 STATIC
  86 EFI_STATUS
  87 DhcpCallUser (
  88   IN  DHCP_SERVICE          *DhcpSb,
  89   IN  EFI_DHCP4_EVENT       Event,
  90   IN  EFI_DHCP4_PACKET      *Packet,      OPTIONAL
  91   OUT EFI_DHCP4_PACKET      **NewPacket   OPTIONAL
  92   )
  93 {
  94   EFI_DHCP4_CONFIG_DATA     *Config;
  95   EFI_STATUS                Status;
  96
  97   if (NewPacket != NULL) {
  98     *NewPacket = NULL;
  99   }
 100
 101   //
 102   // If user doesn't provide the call back function, return the value
 103   // that directs the client to continue the normal process.
 104   // In Dhcp4Selecting EFI_SUCCESS tells the client to stop collecting
 105   // the offers and select a offer, EFI_NOT_READY tells the client to
 106   // collect more offers.
 107   //
 108   Config = &DhcpSb->ActiveConfig;
 109
 110   if (Config->Dhcp4Callback == NULL) {
 111     if (Event == Dhcp4RcvdOffer) {
 112       return EFI_NOT_READY;
 113     }
 114
 115     return EFI_SUCCESS;
 116   }
 117
 118   Status = Config->Dhcp4Callback (
 119                      &DhcpSb->ActiveChild->Dhcp4Protocol,
 120                      Config->CallbackContext,
 121                      (EFI_DHCP4_STATE) DhcpSb->DhcpState,
 122                      Event,
 123                      Packet,
 124                      NewPacket
 125                      );
 126
 127   //
 128   // User's callback should only return EFI_SUCCESS, EFI_NOT_READY,
 129   // and EFI_ABORTED. If it returns values other than those, assume
 130   // it to be EFI_ABORTED.
 131   //
 132   if ((Status == EFI_SUCCESS) || (Status == EFI_NOT_READY)) {
 133     return Status;
 134   }
 135
 136   return EFI_ABORTED;
 137 }
 138
 139
 140 /**
 141   Notify the user about the operation result.
 142
 143   @param  DhcpSb                DHCP service instance
 144   @param  Which                 which notify function to signal
 145
 146   @return None
 147
 148 **/
 149 VOID
 150 DhcpNotifyUser (
 151   IN DHCP_SERVICE           *DhcpSb,
 152   IN INTN                   Which
 153   )
 154 {
 155   DHCP_PROTOCOL             *Child;
 156
 157   if ((Child = DhcpSb->ActiveChild) == NULL) {
 158     return ;
 159   }
 160
 161   if ((Child->CompletionEvent != NULL) &&
 162      ((Which == DHCP_NOTIFY_COMPLETION) || (Which == DHCP_NOTIFY_ALL))) {
 163
 164     gBS->SignalEvent (Child->CompletionEvent);
 165     Child->CompletionEvent = NULL;
 166   }
 167
 168   if ((Child->RenewRebindEvent != NULL) &&
 169      ((Which == DHCP_NOTIFY_RENEWREBIND) || (Which == DHCP_NOTIFY_ALL))) {
 170
 171     gBS->SignalEvent (Child->RenewRebindEvent);
 172     Child->RenewRebindEvent = NULL;
 173   }
 174 }
 175
 176
 177
 178 /**
 179   Set the DHCP state. If CallUser is true, it will try to notify
 180   the user before change the state by DhcpNotifyUser. It returns
 181   EFI_ABORTED if the user return EFI_ABORTED, otherwise, it returns
 182   EFI_SUCCESS. If CallUser is FALSE, it isn't necessary to test
 183   the return value of this function.
 184
 185   @param  DhcpSb                The DHCP service instance
 186   @param  State                 The new DHCP state to change to
 187   @param  CallUser              Whether we need to call user
 188
 189   @retval EFI_SUCCESS           The state is changed
 190   @retval EFI_ABORTED           The user asks to abort the DHCP process.
 191
 192 **/
 193 EFI_STATUS
 194 DhcpSetState (
 195   IN DHCP_SERVICE           *DhcpSb,
 196   IN INTN                   State,
 197   IN BOOLEAN                CallUser
 198   )
 199 {
 200   EFI_STATUS                Status;
 201
 202   if (CallUser) {
 203     Status = EFI_SUCCESS;
 204
 205     if (State == Dhcp4Renewing) {
 206       Status = DhcpCallUser (DhcpSb, Dhcp4EnterRenewing, NULL, NULL);
 207
 208     } else if (State == Dhcp4Rebinding) {
 209       Status = DhcpCallUser (DhcpSb, Dhcp4EnterRebinding, NULL, NULL);
 210
 211     } else if (State == Dhcp4Bound) {
 212       Status = DhcpCallUser (DhcpSb, Dhcp4BoundCompleted, NULL, NULL);
 213
 214     }
 215
 216     if (EFI_ERROR (Status)) {
 217       return Status;
 218     }
 219   }
 220
 221   //
 222   // Update the retransmission timer during the state transition.
 223   // This will clear the retry count. This is also why the rule
 224   // first transit the state, then send packets.
 225   //
 226   if (State == Dhcp4Selecting) {
 227     DhcpSb->MaxRetries = DhcpSb->ActiveConfig.DiscoverTryCount;
 228   } else {
 229     DhcpSb->MaxRetries = DhcpSb->ActiveConfig.RequestTryCount;
 230   }
 231
 232   if (DhcpSb->MaxRetries == 0) {
 233     DhcpSb->MaxRetries = 4;
 234   }
 235
 236   DhcpSb->CurRetry      = 0;
 237   DhcpSb->PacketToLive  = 0;
 238
 239   DhcpSb->DhcpState     = State;
 240   return EFI_SUCCESS;
 241 }
 242
 243
 244 /**
 245   Set the retransmit timer for the packet. It will select from either
 246   the discover timeouts/request timeouts or the default timeout values.
 247
 248   @param  DhcpSb                The DHCP service instance.
 249
 250   @return None
 251
 252 **/
 253 STATIC
 254 VOID
 255 DhcpSetTransmitTimer (
 256   IN DHCP_SERVICE           *DhcpSb
 257   )
 258 {
 259   UINT32                    *Times;
 260
 261   ASSERT (DhcpSb->MaxRetries > DhcpSb->CurRetry);
 262
 263   if (DhcpSb->DhcpState == Dhcp4Selecting) {
 264     Times = DhcpSb->ActiveConfig.DiscoverTimeout;
 265   } else {
 266     Times = DhcpSb->ActiveConfig.RequestTimeout;
 267   }
 268
 269   if (Times == NULL) {
 270     Times = mDhcp4DefaultTimeout;
 271   }
 272
 273   DhcpSb->PacketToLive = Times[DhcpSb->CurRetry];
 274
 275   if (DhcpSb->DhcpState == Dhcp4Selecting) {
 276     DhcpSb->WaitOffer = DhcpSb->PacketToLive;
 277   }
 278 }
 279
 280 /**
 281   Compute the lease. If the server grants a permanent lease, just
 282   process it as a normal timeout value since the lease will last
 283   more than 100 years.
 284
 285   @param  DhcpSb                The DHCP service instance
 286   @param  Para                  The DHCP parameter extracted from the server's
 287                                 response.
 288
 289   @return None
 290
 291 **/
 292 STATIC
 293 VOID
 294 DhcpComputeLease (
 295   IN DHCP_SERVICE           *DhcpSb,
 296   IN DHCP_PARAMETER         *Para
 297   )
 298 {
 299   ASSERT (Para != NULL);
 300
 301   DhcpSb->Lease = Para->Lease;
 302   DhcpSb->T2    = Para->T2;
 303   DhcpSb->T1    = Para->T1;
 304
 305   if (DhcpSb->Lease == 0) {
 306     DhcpSb->Lease = DHCP_DEFAULT_LEASE;
 307   }
 308
 309   if ((DhcpSb->T2 == 0) || (DhcpSb->T2 >= Para->Lease)) {
 310     DhcpSb->T2 = Para->Lease - (Para->Lease >> 3);
 311   }
 312
 313   if ((DhcpSb->T1 == 0) || (DhcpSb->T1 >= Para->T2)) {
 314     DhcpSb->T1 = DhcpSb->Lease >> 1;
 315   }
 316 }
 317
 318
 319 /**
 320   Configure a UDP IO port to use the acquired lease address.
 321   DHCP driver needs this port to unicast packet to the server
 322   such as DHCP release.
 323
 324   @param  UdpIo                 The UDP IO port to configure
 325   @param  Context               The opaque parameter to the function.
 326
 327   @retval EFI_SUCCESS           The UDP IO port is successfully configured.
 328   @retval Others                It failed to configure the port.
 329
 330 **/
 331 EFI_STATUS
 332 DhcpConfigLeaseIoPort (
 333   IN UDP_IO_PORT            *UdpIo,
 334   IN VOID                   *Context
 335   )
 336 {
 337   EFI_UDP4_CONFIG_DATA      UdpConfigData;
 338   EFI_IPv4_ADDRESS          Subnet;
 339   EFI_IPv4_ADDRESS          Gateway;
 340   DHCP_SERVICE              *DhcpSb;
 341   EFI_STATUS                Status;
 342   IP4_ADDR                  Ip;
 343
 344   DhcpSb = (DHCP_SERVICE *) Context;
 345
 346   UdpConfigData.AcceptBroadcast     = FALSE;
 347   UdpConfigData.AcceptPromiscuous   = FALSE;
 348   UdpConfigData.AcceptAnyPort       = FALSE;
 349   UdpConfigData.AllowDuplicatePort  = TRUE;
 350   UdpConfigData.TypeOfService       = 0;
 351   UdpConfigData.TimeToLive          = 64;
 352   UdpConfigData.DoNotFragment       = FALSE;
 353   UdpConfigData.ReceiveTimeout      = 1;
 354   UdpConfigData.TransmitTimeout     = 0;
 355
 356   UdpConfigData.UseDefaultAddress   = FALSE;
 357   UdpConfigData.StationPort         = DHCP_CLIENT_PORT;
 358   UdpConfigData.RemotePort          = DHCP_SERVER_PORT;
 359
 360   Ip = HTONL (DhcpSb->ClientAddr);
 361   CopyMem (&UdpConfigData.StationAddress, &Ip, sizeof (EFI_IPv4_ADDRESS));
 362
 363   Ip = HTONL (DhcpSb->Netmask);
 364   CopyMem (&UdpConfigData.SubnetMask, &Ip, sizeof (EFI_IPv4_ADDRESS));
 365
 366   ZeroMem (&UdpConfigData.RemoteAddress, sizeof (EFI_IPv4_ADDRESS));
 367
 368   Status = UdpIo->Udp->Configure (UdpIo->Udp, &UdpConfigData);
 369
 370   if (EFI_ERROR (Status)) {
 371     return Status;
 372   }
 373
 374   //
 375   // Add a default route if received from the server.
 376   //
 377   if ((DhcpSb->Para != NULL) && (DhcpSb->Para->Router != 0)) {
 378     ZeroMem (&Subnet, sizeof (EFI_IPv4_ADDRESS));
 379
 380     Ip = HTONL (DhcpSb->Para->Router);
 381     CopyMem (&Gateway, &Ip, sizeof (EFI_IPv4_ADDRESS));
 382
 383     UdpIo->Udp->Routes (UdpIo->Udp, FALSE, &Subnet, &Subnet, &Gateway);
 384   }
 385
 386   return EFI_SUCCESS;
 387 }
 388
 389
 390 /**
 391   Update the lease states when a new lease is acquired. It will not only
 392   save the acquired the address and lease time, it will also create a UDP
 393   child to provide address resolution for the address.
 394
 395   @param  DhcpSb                The DHCP service instance
 396
 397   @retval EFI_OUT_OF_RESOURCES  Failed to allocate resources.
 398   @retval EFI_SUCCESS           The lease is recorded.
 399
 400 **/
 401 STATIC
 402 EFI_STATUS
 403 DhcpLeaseAcquired (
 404   IN DHCP_SERVICE           *DhcpSb
 405   )
 406 {
 407   INTN                      Class;
 408
 409   DhcpSb->ClientAddr = EFI_NTOHL (DhcpSb->Selected->Dhcp4.Header.YourAddr);
 410
 411   if (DhcpSb->Para != NULL) {
 412     DhcpSb->Netmask     = DhcpSb->Para->NetMask;
 413     DhcpSb->ServerAddr  = DhcpSb->Para->ServerId;
 414   }
 415
 416   if (DhcpSb->Netmask == 0) {
 417     Class           = NetGetIpClass (DhcpSb->ClientAddr);
 418     DhcpSb->Netmask = mIp4AllMasks[Class << 3];
 419   }
 420
 421   if (DhcpSb->LeaseIoPort != NULL) {
 422     UdpIoFreePort (DhcpSb->LeaseIoPort);
 423   }
 424
 425   //
 426   // Create a UDP/IP child to provide ARP service for the Leased IP,
 427   // and transmit unicast packet with it as source address. Don't
 428   // start receive on this port, the queued packet will be timeout.
 429   //
 430   DhcpSb->LeaseIoPort = UdpIoCreatePort (
 431                           DhcpSb->Controller,
 432                           DhcpSb->Image,
 433                           DhcpConfigLeaseIoPort,
 434                           DhcpSb
 435                           );
 436
 437   if (DhcpSb->LeaseIoPort == NULL) {
 438     return EFI_OUT_OF_RESOURCES;
 439   }
 440
 441   if (!DHCP_IS_BOOTP (DhcpSb->Para)) {
 442     DhcpComputeLease (DhcpSb, DhcpSb->Para);
 443   }
 444
 445   return DhcpSetState (DhcpSb, Dhcp4Bound, TRUE);
 446 }
 447
 448
 449 /**
 450   Clean up the DHCP related states, IoStatus isn't reset.
 451
 452   @param  DhcpSb                The DHCP instance service.
 453
 454   @return None
 455
 456 **/
 457 VOID
 458 DhcpCleanLease (
 459   IN DHCP_SERVICE           *DhcpSb
 460   )
 461 {
 462   DhcpSb->DhcpState   = Dhcp4Init;
 463   DhcpSb->Xid         = DhcpSb->Xid + 1;
 464   DhcpSb->ClientAddr  = 0;
 465   DhcpSb->ServerAddr  = 0;
 466
 467   if (DhcpSb->LastOffer != NULL) {
 468     gBS->FreePool (DhcpSb->LastOffer);
 469     DhcpSb->LastOffer = NULL;
 470   }
 471
 472   if (DhcpSb->Selected != NULL) {
 473     gBS->FreePool (DhcpSb->Selected);
 474     DhcpSb->Selected = NULL;
 475   }
 476
 477   if (DhcpSb->Para != NULL) {
 478     gBS->FreePool (DhcpSb->Para);
 479     DhcpSb->Para = NULL;
 480   }
 481
 482   DhcpSb->Lease         = 0;
 483   DhcpSb->T1            = 0;
 484   DhcpSb->T2            = 0;
 485   DhcpSb->ExtraRefresh  = FALSE;
 486
 487   if (DhcpSb->LeaseIoPort != NULL) {
 488     UdpIoFreePort (DhcpSb->LeaseIoPort);
 489     DhcpSb->LeaseIoPort = NULL;
 490   }
 491
 492   if (DhcpSb->LastPacket != NULL) {
 493     NetbufFree (DhcpSb->LastPacket);
 494     DhcpSb->LastPacket = NULL;
 495   }
 496
 497   DhcpSb->PacketToLive  = 0;
 498   DhcpSb->CurRetry      = 0;
 499   DhcpSb->MaxRetries    = 0;
 500   DhcpSb->WaitOffer     = 0;
 501   DhcpSb->LeaseLife     = 0;
 502 }
 503
 504
 505 /**
 506   Select a offer among all the offers collected. If the offer selected is
 507   of BOOTP, the lease is recorded and user notified. If the offer is of
 508   DHCP, it will request the offer from the server.
 509
 510   @param  DhcpSb                The DHCP service instance.
 511
 512   @retval EFI_SUCCESS           One of the offer is selected.
 513
 514 **/
 515 STATIC
 516 EFI_STATUS
 517 DhcpChooseOffer (
 518   IN DHCP_SERVICE           *DhcpSb
 519   )
 520 {
 521   EFI_DHCP4_PACKET          *Selected;
 522   EFI_DHCP4_PACKET          *NewPacket;
 523   EFI_DHCP4_PACKET          *TempPacket;
 524   EFI_STATUS                Status;
 525
 526   ASSERT (DhcpSb->LastOffer != NULL);
 527
 528   //
 529   // Stop waiting more offers
 530   //
 531   DhcpSb->WaitOffer = 0;
 532
 533   //
 534   // User will cache previous offers if he wants to select
 535   // from multiple offers. If user provides an invalid packet,
 536   // use the last offer, otherwise use the provided packet.
 537   //
 538   NewPacket = NULL;
 539   Status    = DhcpCallUser (DhcpSb, Dhcp4SelectOffer, DhcpSb->LastOffer, &NewPacket);
 540
 541   if (EFI_ERROR (Status)) {
 542     return Status;
 543   }
 544
 545   Selected = DhcpSb->LastOffer;
 546
 547   if ((NewPacket != NULL) && !EFI_ERROR (DhcpValidateOptions (NewPacket, NULL))) {
 548     TempPacket = (EFI_DHCP4_PACKET *) AllocatePool (NewPacket->Size);
 549     if (TempPacket != NULL) {
 550       CopyMem (TempPacket, NewPacket, NewPacket->Size);
 551       gBS->FreePool (Selected);
 552       Selected = TempPacket;
 553     }
 554   }
 555
 556   DhcpSb->Selected  = Selected;
 557   DhcpSb->LastOffer = NULL;
 558   DhcpSb->Para      = NULL;
 559   DhcpValidateOptions (Selected, &DhcpSb->Para);
 560
 561   //
 562   // A bootp offer has been selected, save the lease status,
 563   // enter bound state then notify the user.
 564   //
 565   if (DHCP_IS_BOOTP (DhcpSb->Para)) {
 566     Status = DhcpLeaseAcquired (DhcpSb);
 567
 568     if (EFI_ERROR (Status)) {
 569       return Status;
 570     }
 571
 572     DhcpSb->IoStatus = EFI_SUCCESS;
 573     DhcpNotifyUser (DhcpSb, DHCP_NOTIFY_ALL);
 574     return EFI_SUCCESS;
 575   }
 576
 577   //
 578   // Send a DHCP requests
 579   //
 580   Status = DhcpSetState (DhcpSb, Dhcp4Requesting, TRUE);
 581
 582   if (EFI_ERROR (Status)) {
 583     return Status;
 584   }
 585
 586   return DhcpSendMessage (DhcpSb, Selected, DhcpSb->Para, DHCP_MSG_REQUEST, NULL);
 587 }
 588
 589
 590 /**
 591   Terminate the current address acquire. All the allocated resources
 592   are released. Be careful when calling this function. A rule related
 593   to this is: only call DhcpEndSession at the highest level, such as
 594   DhcpInput, DhcpOnTimerTick...At the other level, just return error.
 595
 596   @param  DhcpSb                The DHCP service instance
 597   @param  Status                The result of the DHCP process.
 598
 599   @return None
 600
 601 **/
 602 STATIC
 603 VOID
 604 DhcpEndSession (
 605   IN DHCP_SERVICE           *DhcpSb,
 606   IN EFI_STATUS             Status
 607   )
 608 {
 609   if (DHCP_CONNECTED (DhcpSb->DhcpState)) {
 610     DhcpCallUser (DhcpSb, Dhcp4AddressLost, NULL, NULL);
 611   } else {
 612     DhcpCallUser (DhcpSb, Dhcp4Fail, NULL, NULL);
 613   }
 614
 615   DhcpCleanLease (DhcpSb);
 616
 617   DhcpSb->IoStatus = Status;
 618   DhcpNotifyUser (DhcpSb, DHCP_NOTIFY_ALL);
 619 }
 620
 621
 622 /**
 623   Handle packets in DHCP select state.
 624
 625   @param  DhcpSb                The DHCP service instance
 626   @param  Packet                The DHCP packet received
 627   @param  Para                  The DHCP parameter extracted from the packet. That
 628                                 is, all the option value that we care.
 629
 630   @retval EFI_SUCCESS           The packet is successfully processed.
 631   @retval Others                Some error occured.
 632
 633 **/
 634 STATIC
 635 EFI_STATUS
 636 DhcpHandleSelect (
 637   IN DHCP_SERVICE           *DhcpSb,
 638   IN EFI_DHCP4_PACKET       *Packet,
 639   IN DHCP_PARAMETER         *Para
 640   )
 641 {
 642   EFI_STATUS                Status;
 643
 644   Status = EFI_SUCCESS;
 645
 646   //
 647   // First validate the message:
 648   // 1. the offer is a unicast
 649   // 2. if it is a DHCP message, it must contains a server ID.
 650   // Don't return a error for these two case otherwise the session is ended.
 651   //
 652   if (!DHCP_IS_BOOTP (Para) &&
 653      ((Para->DhcpType != DHCP_MSG_OFFER) || (Para->ServerId == 0))) {
 654     goto ON_EXIT;
 655   }
 656
 657   //
 658   // Call the user's callback. The action according to the return is as:
 659   // 1. EFI_SUCESS: stop waiting for more offers, select the offer now
 660   // 2. EFI_NOT_READY: wait for more offers
 661   // 3. EFI_ABORTED: abort the address acquiring.
 662   //
 663   Status = DhcpCallUser (DhcpSb, Dhcp4RcvdOffer, Packet, NULL);
 664
 665   if (Status == EFI_SUCCESS) {
 666     if (DhcpSb->LastOffer != NULL) {
 667       gBS->FreePool (DhcpSb->LastOffer);
 668     }
 669
 670     DhcpSb->LastOffer = Packet;
 671
 672     return DhcpChooseOffer (DhcpSb);
 673
 674   } else if (Status == EFI_NOT_READY) {
 675     if (DhcpSb->LastOffer != NULL) {
 676       gBS->FreePool (DhcpSb->LastOffer);
 677     }
 678
 679     DhcpSb->LastOffer = Packet;
 680
 681   } else if (Status == EFI_ABORTED) {
 682     //
 683     // DhcpInput will end the session upon error return. Remember
 684     // only to call DhcpEndSession at the top level call.
 685     //
 686     goto ON_EXIT;
 687   }
 688
 689   return EFI_SUCCESS;
 690
 691 ON_EXIT:
 692   gBS->FreePool (Packet);
 693   return Status;
 694 }
 695
 696
 697 /**
 698   Handle packets in DHCP request state.
 699
 700   @param  DhcpSb                The DHCP service instance
 701   @param  Packet                The DHCP packet received
 702   @param  Para                  The DHCP parameter extracted from the packet. That
 703                                 is, all the option value that we care.
 704
 705   @retval EFI_SUCCESS           The packet is successfully processed.
 706   @retval Others                Some error occured.
 707
 708 **/
 709 STATIC
 710 EFI_STATUS
 711 DhcpHandleRequest (
 712   IN DHCP_SERVICE           *DhcpSb,
 713   IN EFI_DHCP4_PACKET       *Packet,
 714   IN DHCP_PARAMETER         *Para
 715   )
 716 {
 717   EFI_DHCP4_HEADER          *Head;
 718   EFI_DHCP4_HEADER          *Selected;
 719   EFI_STATUS                Status;
 720   UINT8                     *Message;
 721
 722   ASSERT (!DHCP_IS_BOOTP (DhcpSb->Para));
 723
 724   Head      = &Packet->Dhcp4.Header;
 725   Selected  = &DhcpSb->Selected->Dhcp4.Header;
 726
 727   //
 728   // Ignore the BOOTP message and DHCP messages other than DHCP ACK/NACK.
 729   //
 730   if (DHCP_IS_BOOTP (Para) ||
 731      (Para->ServerId != DhcpSb->Para->ServerId) ||
 732      ((Para->DhcpType != DHCP_MSG_ACK) && (Para->DhcpType != DHCP_MSG_NAK))) {
 733
 734     Status = EFI_SUCCESS;
 735     goto ON_EXIT;
 736   }
 737
 738   //
 739   // Received a NAK, end the session no matter what the user returns
 740   //
 741   Status = EFI_DEVICE_ERROR;
 742
 743   if (Para->DhcpType == DHCP_MSG_NAK) {
 744     DhcpCallUser (DhcpSb, Dhcp4RcvdNak, Packet, NULL);
 745     goto ON_EXIT;
 746   }
 747
 748   //
 749   // Check whether the ACK matches the selected offer
 750   //
 751   Message = NULL;
 752
 753   if (!EFI_IP4_EQUAL (&Head->YourAddr, &Selected->YourAddr)) {
 754     Message = (UINT8 *) "Lease confirmed isn't the same as that in the offer";
 755     goto REJECT;
 756   }
 757
 758   Status = DhcpCallUser (DhcpSb, Dhcp4RcvdAck, Packet, NULL);
 759
 760   if (EFI_ERROR (Status)) {
 761     Message = (UINT8 *) "Lease is denied upon received ACK";
 762     goto REJECT;
 763   }
 764
 765   //
 766   // Record the lease, transit to BOUND state, then notify the user
 767   //
 768   Status = DhcpLeaseAcquired (DhcpSb);
 769
 770   if (EFI_ERROR (Status)) {
 771     Message = (UINT8 *) "Lease is denied upon entering bound";
 772     goto REJECT;
 773   }
 774
 775   DhcpSb->IoStatus = EFI_SUCCESS;
 776   DhcpNotifyUser (DhcpSb, DHCP_NOTIFY_COMPLETION);
 777
 778   gBS->FreePool (Packet);
 779   return EFI_SUCCESS;
 780
 781 REJECT:
 782   DhcpSendMessage (DhcpSb, DhcpSb->Selected, DhcpSb->Para, DHCP_MSG_DECLINE, Message);
 783
 784 ON_EXIT:
 785   gBS->FreePool (Packet);
 786   return Status;
 787 }
 788
 789
 790 /**
 791   Handle packets in DHCP renew/rebound state.
 792
 793   @param  DhcpSb                The DHCP service instance
 794   @param  Packet                The DHCP packet received
 795   @param  Para                  The DHCP parameter extracted from the packet. That
 796                                 is, all the option value that we care.
 797
 798   @retval EFI_SUCCESS           The packet is successfully processed.
 799   @retval Others                Some error occured.
 800
 801 **/
 802 STATIC
 803 EFI_STATUS
 804 DhcpHandleRenewRebind (
 805   IN DHCP_SERVICE           *DhcpSb,
 806   IN EFI_DHCP4_PACKET       *Packet,
 807   IN DHCP_PARAMETER         *Para
 808   )
 809 {
 810   EFI_DHCP4_HEADER          *Head;
 811   EFI_DHCP4_HEADER          *Selected;
 812   EFI_STATUS                Status;
 813
 814   ASSERT (!DHCP_IS_BOOTP (DhcpSb->Para));
 815
 816   Head      = &Packet->Dhcp4.Header;
 817   Selected  = &DhcpSb->Selected->Dhcp4.Header;
 818
 819   //
 820   // Ignore the BOOTP message and DHCP messages other than DHCP ACK/NACK
 821   //
 822   if (DHCP_IS_BOOTP (Para) ||
 823      (Para->ServerId != DhcpSb->Para->ServerId) ||
 824      ((Para->DhcpType != DHCP_MSG_ACK) && (Para->DhcpType != DHCP_MSG_NAK))) {
 825
 826     Status = EFI_SUCCESS;
 827     goto ON_EXIT;
 828   }
 829
 830   //
 831   // Received a NAK, ignore the user's return then terminate the process
 832   //
 833   Status = EFI_DEVICE_ERROR;
 834
 835   if (Para->DhcpType == DHCP_MSG_NAK) {
 836     DhcpCallUser (DhcpSb, Dhcp4RcvdNak, Packet, NULL);
 837     goto ON_EXIT;
 838   }
 839
 840   //
 841   // The lease is different from the selected. Don't send a DECLINE
 842   // since it isn't existed in the client's FSM.
 843   //
 844   if (!EFI_IP4_EQUAL (&Head->YourAddr, &Selected->YourAddr)) {
 845     goto ON_EXIT;
 846   }
 847
 848   Status = DhcpCallUser (DhcpSb, Dhcp4RcvdAck, Packet, NULL);
 849
 850   if (EFI_ERROR (Status)) {
 851     goto ON_EXIT;
 852   }
 853
 854   //
 855   // Record the lease, start timer for T1 and T2,
 856   //
 857   DhcpComputeLease (DhcpSb, Para);
 858   DhcpSb->LeaseLife = 0;
 859   DhcpSetState (DhcpSb, Dhcp4Bound, TRUE);
 860
 861   if (DhcpSb->ExtraRefresh) {
 862     DhcpSb->ExtraRefresh  = FALSE;
 863
 864     DhcpSb->IoStatus      = EFI_SUCCESS;
 865     DhcpNotifyUser (DhcpSb, DHCP_NOTIFY_RENEWREBIND);
 866   }
 867
 868 ON_EXIT:
 869   gBS->FreePool (Packet);
 870   return Status;
 871 }
 872
 873
 874 /**
 875   Handle packets in DHCP reboot state.
 876
 877   @param  DhcpSb                The DHCP service instance
 878   @param  Packet                The DHCP packet received
 879   @param  Para                  The DHCP parameter extracted from the packet. That
 880                                 is, all the option value that we care.
 881
 882   @retval EFI_SUCCESS           The packet is successfully processed.
 883   @retval Others                Some error occured.
 884
 885 **/
 886 STATIC
 887 EFI_STATUS
 888 DhcpHandleReboot (
 889   IN DHCP_SERVICE           *DhcpSb,
 890   IN EFI_DHCP4_PACKET       *Packet,
 891   IN DHCP_PARAMETER         *Para
 892   )
 893 {
 894   EFI_DHCP4_HEADER          *Head;
 895   EFI_STATUS                Status;
 896
 897   Head = &Packet->Dhcp4.Header;
 898
 899   //
 900   // Ignore the BOOTP message and DHCP messages other than DHCP ACK/NACK
 901   //
 902   if (DHCP_IS_BOOTP (Para) ||
 903      ((Para->DhcpType != DHCP_MSG_ACK) && (Para->DhcpType != DHCP_MSG_NAK))) {
 904
 905     Status = EFI_SUCCESS;
 906     goto ON_EXIT;
 907   }
 908
 909   //
 910   // If a NAK is received, transit to INIT and try again.
 911   //
 912   if (Para->DhcpType == DHCP_MSG_NAK) {
 913     DhcpCallUser (DhcpSb, Dhcp4RcvdNak, Packet, NULL);
 914
 915     DhcpSb->ClientAddr  = 0;
 916     DhcpSb->DhcpState   = Dhcp4Init;
 917
 918     Status              = DhcpInitRequest (DhcpSb);
 919     goto ON_EXIT;
 920   }
 921
 922   //
 923   // Check whether the ACK matches the selected offer
 924   //
 925   if (EFI_NTOHL (Head->YourAddr) != DhcpSb->ClientAddr) {
 926     Status = EFI_DEVICE_ERROR;
 927     goto ON_EXIT;
 928   }
 929
 930   Status = DhcpCallUser (DhcpSb, Dhcp4RcvdAck, Packet, NULL);
 931   if (EFI_ERROR (Status)) {
 932     goto ON_EXIT;
 933   }
 934
 935   //
 936   // OK, get the parameter from server, record the lease
 937   //
 938   DhcpSb->Para = AllocatePool (sizeof (DHCP_PARAMETER));
 939
 940   if (DhcpSb->Para == NULL) {
 941     Status = EFI_OUT_OF_RESOURCES;
 942     goto ON_EXIT;
 943   }
 944
 945   DhcpSb->Selected  = Packet;
 946   CopyMem (DhcpSb->Para, Para, sizeof (*DhcpSb->Para));
 947
 948   Status            = DhcpLeaseAcquired (DhcpSb);
 949
 950   if (EFI_ERROR (Status)) {
 951     return Status;
 952   }
 953
 954   DhcpSb->IoStatus = EFI_SUCCESS;
 955   DhcpNotifyUser (DhcpSb, DHCP_NOTIFY_COMPLETION);
 956   return EFI_SUCCESS;
 957
 958 ON_EXIT:
 959   gBS->FreePool (Packet);
 960   return Status;
 961 }
 962
 963
 964 /**
 965   Handle the received DHCP packets. This function drivers the DHCP
 966   state machine.
 967
 968   @param  UdpPacket             The UDP packets received.
 969   @param  Points                The local/remote UDP access points
 970   @param  IoStatus              The status of the UDP receive
 971   @param  Context               The opaque parameter to the function.
 972
 973   @return None
 974
 975 **/
 976 VOID
 977 DhcpInput (
 978   NET_BUF                   *UdpPacket,
 979   UDP_POINTS                *Points,
 980   EFI_STATUS                IoStatus,
 981   VOID                      *Context
 982   )
 983 {
 984   DHCP_SERVICE              *DhcpSb;
 985   EFI_DHCP4_HEADER          *Head;
 986   EFI_DHCP4_PACKET          *Packet;
 987   DHCP_PARAMETER            *Para;
 988   EFI_STATUS                Status;
 989   UINT32                    Len;
 990
 991   Packet  = NULL;
 992   DhcpSb  = (DHCP_SERVICE *) Context;
 993
 994   //
 995   // Don't restart receive if error occurs or DHCP is destoried.
 996   //
 997   if (EFI_ERROR (IoStatus)) {
 998     return ;
 999   } else if (DhcpSb->ServiceState == DHCP_DESTORY) {
1000     NetbufFree (UdpPacket);
1001     return ;
1002   }
1003
1004   ASSERT (UdpPacket != NULL);
1005
1006   if (DhcpSb->DhcpState == Dhcp4Stopped) {
1007     goto RESTART;
1008   }
1009
1010   //
1011   // Validate the packet received
1012   //
1013   if (UdpPacket->TotalSize < sizeof (EFI_DHCP4_HEADER)) {
1014     goto RESTART;
1015   }
1016
1017   //
1018   // Copy the DHCP message to a continuous memory block
1019   //
1020   Len     = sizeof (EFI_DHCP4_PACKET) + UdpPacket->TotalSize - sizeof (EFI_DHCP4_HEADER);
1021   Packet  = (EFI_DHCP4_PACKET *) AllocatePool (Len);
1022
1023   if (Packet == NULL) {
1024     goto RESTART;
1025   }
1026
1027   Packet->Size    = Len;
1028   Head            = &Packet->Dhcp4.Header;
1029   Packet->Length  = NetbufCopy (UdpPacket, 0, UdpPacket->TotalSize, (UINT8 *) Head);
1030
1031   if (Packet->Length != UdpPacket->TotalSize) {
1032     goto RESTART;
1033   }
1034
1035   //
1036   // Is this packet the answer to our packet?
1037   //
1038   if ((Head->OpCode != BOOTP_REPLY) ||
1039       (NTOHL (Head->Xid) != DhcpSb->Xid) ||
1040       (CompareMem (DhcpSb->ClientAddressSendOut, Head->ClientHwAddr, Head->HwAddrLen) != 0)) {
1041     goto RESTART;
1042   }
1043
1044   //
1045   // Validate the options and retrieve the interested options
1046   //
1047   Para = NULL;
1048   if ((Packet->Length > sizeof (EFI_DHCP4_HEADER) + sizeof (UINT32)) &&
1049       (Packet->Dhcp4.Magik == DHCP_OPTION_MAGIC) &&
1050       EFI_ERROR (DhcpValidateOptions (Packet, &Para))) {
1051
1052     goto RESTART;
1053   }
1054
1055   //
1056   // Call the handler for each state. The handler should return
1057   // EFI_SUCCESS if the process can go on no matter whether the
1058   // packet is ignored or not. If the return is EFI_ERROR, the
1059   // session will be terminated. Packet's ownership is handled
1060   // over to the handlers. If operation succeeds, the handler
1061   // must notify the user. It isn't necessary to do if EFI_ERROR
1062   // is returned because the DhcpEndSession will notify the user.
1063   //
1064   Status = EFI_SUCCESS;
1065
1066   switch (DhcpSb->DhcpState) {
1067   case Dhcp4Selecting:
1068     Status = DhcpHandleSelect (DhcpSb, Packet, Para);
1069     break;
1070
1071   case Dhcp4Requesting:
1072     Status = DhcpHandleRequest (DhcpSb, Packet, Para);
1073     break;
1074
1075   case Dhcp4InitReboot:
1076   case Dhcp4Init:
1077   case Dhcp4Bound:
1078     //
1079     // Ignore the packet in INITREBOOT, INIT and BOUND states
1080     //
1081     gBS->FreePool (Packet);
1082     Status = EFI_SUCCESS;
1083     break;
1084
1085   case Dhcp4Renewing:
1086   case Dhcp4Rebinding:
1087     Status = DhcpHandleRenewRebind (DhcpSb, Packet, Para);
1088     break;
1089
1090   case Dhcp4Rebooting:
1091     Status = DhcpHandleReboot (DhcpSb, Packet, Para);
1092     break;
1093   }
1094
1095   if (Para != NULL) {
1096     gBS->FreePool (Para);
1097   }
1098
1099   Packet = NULL;
1100
1101   if (EFI_ERROR (Status)) {
1102     NetbufFree (UdpPacket);
1103     DhcpEndSession (DhcpSb, Status);
1104     return ;
1105   }
1106
1107 RESTART:
1108   NetbufFree (UdpPacket);
1109
1110   if (Packet != NULL) {
1111     gBS->FreePool (Packet);
1112   }
1113
1114   Status = UdpIoRecvDatagram (DhcpSb->UdpIo, DhcpInput, DhcpSb, 0);
1115
1116   if (EFI_ERROR (Status)) {
1117     DhcpEndSession (DhcpSb, EFI_DEVICE_ERROR);
1118   }
1119 }
1120
1121
1122 /**
1123   Release the packet.
1124
1125   @param  Arg                   The packet to release
1126
1127   @return None
1128
1129 **/
1130 VOID
1131 DhcpReleasePacket (
1132   IN VOID                   *Arg
1133   )
1134 {
1135   gBS->FreePool (Arg);
1136 }
1137
1138
1139 /**
1140   Release the net buffer when packet is sent.
1141
1142   @param  UdpPacket             The UDP packets received.
1143   @param  Points                The local/remote UDP access points
1144   @param  IoStatus              The status of the UDP receive
1145   @param  Context               The opaque parameter to the function.
1146
1147   @return None
1148
1149 **/
1150 VOID
1151 DhcpOnPacketSent (
1152   NET_BUF                   *Packet,
1153   UDP_POINTS                *Points,
1154   EFI_STATUS                IoStatus,
1155   VOID                      *Context
1156   )
1157 {
1158   NetbufFree (Packet);
1159 }
1160
1161
1162
1163 /**
1164   Build and transmit a DHCP message according to the current states.
1165   This function implement the Table 5. of RFC 2131. Always transits
1166   the state (as defined in Figure 5. of the same RFC) before sending
1167   a DHCP message. The table is adjusted accordingly.
1168
1169   @param  DhcpSb                The DHCP service instance
1170   @param  Seed                  The seed packet which the new packet is based on
1171   @param  Para                  The DHCP parameter of the Seed packet
1172   @param  Type                  The message type to send
1173   @param  Msg                   The human readable message to include in the packet
1174                                 sent.
1175
1176   @retval EFI_OUT_OF_RESOURCES  Failed to allocate resources for the packet
1177   @retval EFI_ACCESS_DENIED     Failed to transmit the packet through UDP
1178   @retval EFI_SUCCESS           The message is sent
1179
1180 **/
1181 EFI_STATUS
1182 DhcpSendMessage (
1183   IN DHCP_SERVICE           *DhcpSb,
1184   IN EFI_DHCP4_PACKET       *Seed,
1185   IN DHCP_PARAMETER         *Para,
1186   IN UINT8                  Type,
1187   IN UINT8                  *Msg
1188   )
1189 {
1190   EFI_DHCP4_CONFIG_DATA     *Config;
1191   EFI_DHCP4_PACKET          *Packet;
1192   EFI_DHCP4_PACKET          *NewPacket;
1193   EFI_DHCP4_HEADER          *Head;
1194   EFI_DHCP4_HEADER          *SeedHead;
1195   UDP_IO_PORT               *UdpIo;
1196   UDP_POINTS                EndPoint;
1197   NET_BUF                   *Wrap;
1198   NET_FRAGMENT              Frag;
1199   EFI_STATUS                Status;
1200   IP4_ADDR                  IpAddr;
1201   UINT8                     *Buf;
1202   UINT16                    MaxMsg;
1203   UINT32                    Len;
1204   UINT32                    Index;
1205
1206   //
1207   // Allocate a big enough memory block to hold the DHCP packet
1208   //
1209   Len = sizeof (EFI_DHCP4_PACKET) + 128 + DhcpSb->UserOptionLen;
1210
1211   if (Msg != NULL) {
1212     Len += (UINT32)AsciiStrLen ((CHAR8 *) Msg);
1213   }
1214
1215   Packet = AllocatePool (Len);
1216
1217   if (Packet == NULL) {
1218     return EFI_OUT_OF_RESOURCES;
1219   }
1220
1221   Packet->Size    = Len;
1222   Packet->Length  = sizeof (EFI_DHCP4_HEADER) + sizeof (UINT32);
1223
1224   //
1225   // Fill in the DHCP header fields
1226   //
1227   Config    = &DhcpSb->ActiveConfig;
1228   SeedHead  = NULL;
1229
1230   if (Seed != NULL) {
1231     SeedHead = &Seed->Dhcp4.Header;
1232   }
1233
1234   Head = &Packet->Dhcp4.Header;
1235   ZeroMem (Head, sizeof (EFI_DHCP4_HEADER));
1236
1237   Head->OpCode       = BOOTP_REQUEST;
1238   Head->HwType       = DhcpSb->HwType;
1239   Head->HwAddrLen    = DhcpSb->HwLen;
1240   Head->Xid          = HTONL (DhcpSb->Xid);
1241   Head->Reserved     = HTONS (0x8000);  //Server, broadcast the message please.
1242
1243   EFI_IP4 (Head->ClientAddr) = HTONL (DhcpSb->ClientAddr);
1244   CopyMem (Head->ClientHwAddr, DhcpSb->Mac.Addr, DhcpSb->HwLen);
1245
1246   //
1247   // Append the DHCP message type
1248   //
1249   Packet->Dhcp4.Magik = DHCP_OPTION_MAGIC;
1250   Buf                 = Packet->Dhcp4.Option;
1251   Buf                 = DhcpAppendOption (Buf, DHCP_TAG_TYPE, 1, &Type);
1252
1253   //
1254   // Append the serverid option if necessary:
1255   //   1. DHCP decline message
1256   //   2. DHCP release message
1257   //   3. DHCP request to confirm one lease.
1258   //
1259   if ((Type == DHCP_MSG_DECLINE) || (Type == DHCP_MSG_RELEASE) ||
1260       ((Type == DHCP_MSG_REQUEST) && (DhcpSb->DhcpState == Dhcp4Requesting))) {
1261
1262     ASSERT ((Para != NULL) && (Para->ServerId != 0));
1263
1264     IpAddr  = HTONL (Para->ServerId);
1265     Buf     = DhcpAppendOption (Buf, DHCP_TAG_SERVER_ID, 4, (UINT8 *) &IpAddr);
1266   }
1267
1268   //
1269   // Append the requested IP option if necessary:
1270   //   1. DHCP request to use the previously allocated address
1271   //   2. DHCP request to confirm one lease
1272   //   3. DHCP decline to decline one lease
1273   //
1274   IpAddr = 0;
1275
1276   if (Type == DHCP_MSG_REQUEST) {
1277     if (DhcpSb->DhcpState == Dhcp4Rebooting) {
1278       IpAddr = EFI_IP4 (Config->ClientAddress);
1279
1280     } else if (DhcpSb->DhcpState == Dhcp4Requesting) {
1281       ASSERT (SeedHead != NULL);
1282       IpAddr = EFI_IP4 (SeedHead->YourAddr);
1283     }
1284
1285   } else if (Type == DHCP_MSG_DECLINE) {
1286     ASSERT (SeedHead != NULL);
1287     IpAddr = EFI_IP4 (SeedHead->YourAddr);
1288   }
1289
1290   if (IpAddr != 0) {
1291     Buf = DhcpAppendOption (Buf, DHCP_TAG_REQUEST_IP, 4, (UINT8 *) &IpAddr);
1292   }
1293
1294   //
1295   // Append the Max Message Length option if it isn't a DECLINE
1296   // or RELEASE to direct the server use large messages instead of
1297   // override the BOOTFILE and SERVER fields in the message head.
1298   //
1299   if ((Type != DHCP_MSG_DECLINE) && (Type != DHCP_MSG_RELEASE)) {
1300     MaxMsg  = HTONS (0xFF00);
1301     Buf     = DhcpAppendOption (Buf, DHCP_TAG_MAXMSG, 2, (UINT8 *) &MaxMsg);
1302   }
1303
1304   //
1305   // Append the user's message if it isn't NULL
1306   //
1307   if (Msg != NULL) {
1308     Len     = MIN ((UINT32) AsciiStrLen ((CHAR8 *) Msg), 255);
1309     Buf     = DhcpAppendOption (Buf, DHCP_TAG_MESSAGE, (UINT16) Len, Msg);
1310   }
1311
1312   //
1313   // Append the user configured options
1314   //
1315   if (DhcpSb->UserOptionLen != 0) {
1316     for (Index = 0; Index < Config->OptionCount; Index++) {
1317       //
1318       // We can't use any option other than the client ID from user
1319       // if it is a DHCP decline or DHCP release .
1320       //
1321       if (((Type == DHCP_MSG_DECLINE) || (Type == DHCP_MSG_RELEASE)) &&
1322           (Config->OptionList[Index]->OpCode != DHCP_TAG_CLIENT_ID)) {
1323         continue;
1324       }
1325
1326       Buf = DhcpAppendOption (
1327               Buf,
1328               Config->OptionList[Index]->OpCode,
1329               Config->OptionList[Index]->Length,
1330               Config->OptionList[Index]->Data
1331               );
1332     }
1333   }
1334
1335   *(Buf++) = DHCP_TAG_EOP;
1336   Packet->Length += (UINT32) (Buf - Packet->Dhcp4.Option);
1337
1338   //
1339   // OK, the message is built, call the user to override it.
1340   //
1341   Status    = EFI_SUCCESS;
1342   NewPacket = NULL;
1343
1344   if (Type == DHCP_MSG_DISCOVER) {
1345     Status = DhcpCallUser (DhcpSb, Dhcp4SendDiscover, Packet, &NewPacket);
1346
1347   } else if (Type == DHCP_MSG_REQUEST) {
1348     Status = DhcpCallUser (DhcpSb, Dhcp4SendRequest, Packet, &NewPacket);
1349
1350   } else if (Type == DHCP_MSG_DECLINE) {
1351     Status = DhcpCallUser (DhcpSb, Dhcp4SendDecline, Packet, &NewPacket);
1352   }
1353
1354   if (EFI_ERROR (Status)) {
1355     gBS->FreePool (Packet);
1356     return Status;
1357   }
1358
1359   if (NewPacket != NULL) {
1360     gBS->FreePool (Packet);
1361     Packet = NewPacket;
1362   }
1363
1364   //
1365   // Save the Client Address will be sent out
1366   //
1367   CopyMem (&DhcpSb->ClientAddressSendOut[0], &Packet->Dhcp4.Header.ClientHwAddr[0], Packet->Dhcp4.Header.HwAddrLen);
1368
1369
1370   //
1371   // Wrap it into a netbuf then send it.
1372   //
1373   Frag.Bulk = (UINT8 *) &Packet->Dhcp4.Header;
1374   Frag.Len  = Packet->Length;
1375   Wrap      = NetbufFromExt (&Frag, 1, 0, 0, DhcpReleasePacket, Packet);
1376
1377   if (Wrap == NULL) {
1378     gBS->FreePool (Packet);
1379     return EFI_OUT_OF_RESOURCES;
1380   }
1381
1382   //
1383   // Save it as the last sent packet for retransmission
1384   //
1385   if (DhcpSb->LastPacket != NULL) {
1386     NetbufFree (DhcpSb->LastPacket);
1387   }
1388
1389   NET_GET_REF (Wrap);
1390   DhcpSb->LastPacket = Wrap;
1391   DhcpSetTransmitTimer (DhcpSb);
1392
1393   //
1394   // Broadcast the message, unless we know the server address.
1395   // Use the lease UdpIo port to send the unicast packet.
1396   //
1397   EndPoint.RemoteAddr = 0xffffffff;
1398   EndPoint.LocalAddr  = 0;
1399   EndPoint.RemotePort = DHCP_SERVER_PORT;
1400   EndPoint.LocalPort  = DHCP_CLIENT_PORT;
1401   UdpIo               = DhcpSb->UdpIo;
1402
1403   if ((DhcpSb->DhcpState == Dhcp4Renewing) || (Type == DHCP_MSG_RELEASE)) {
1404     EndPoint.RemoteAddr = DhcpSb->ServerAddr;
1405     EndPoint.LocalAddr  = DhcpSb->ClientAddr;
1406     UdpIo               = DhcpSb->LeaseIoPort;
1407   }
1408
1409   ASSERT (UdpIo != NULL);
1410   Status = UdpIoSendDatagram (UdpIo, Wrap, &EndPoint, 0, DhcpOnPacketSent, DhcpSb);
1411
1412   if (EFI_ERROR (Status)) {
1413     NetbufFree (Wrap);
1414     return EFI_ACCESS_DENIED;
1415   }
1416
1417   return EFI_SUCCESS;
1418 }
1419
1420
1421 /**
1422   Retransmit a saved packet. Only DISCOVER and REQUEST messages
1423   will be retransmitted.
1424
1425   @param  DhcpSb                The DHCP service instance
1426
1427   @retval EFI_ACCESS_DENIED     Failed to transmit packet through UDP port
1428   @retval EFI_SUCCESS           The packet is retransmitted.
1429
1430 **/
1431 EFI_STATUS
1432 DhcpRetransmit (
1433   IN DHCP_SERVICE           *DhcpSb
1434   )
1435 {
1436   UDP_IO_PORT               *UdpIo;
1437   UDP_POINTS                EndPoint;
1438   EFI_STATUS                Status;
1439
1440   ASSERT (DhcpSb->LastPacket != NULL);
1441
1442   //
1443   // Broadcast the message, unless we know the server address.
1444   //
1445   EndPoint.RemotePort = DHCP_SERVER_PORT;
1446   EndPoint.LocalPort  = DHCP_CLIENT_PORT;
1447   EndPoint.RemoteAddr = 0xffffffff;
1448   EndPoint.LocalAddr  = 0;
1449   UdpIo               = DhcpSb->UdpIo;
1450
1451   if (DhcpSb->DhcpState == Dhcp4Renewing) {
1452     EndPoint.RemoteAddr = DhcpSb->ServerAddr;
1453     EndPoint.LocalAddr  = DhcpSb->ClientAddr;
1454     UdpIo               = DhcpSb->LeaseIoPort;
1455   }
1456
1457   ASSERT (UdpIo != NULL);
1458
1459   NET_GET_REF (DhcpSb->LastPacket);
1460   Status = UdpIoSendDatagram (
1461              UdpIo,
1462              DhcpSb->LastPacket,
1463              &EndPoint,
1464              0,
1465              DhcpOnPacketSent,
1466              DhcpSb
1467              );
1468
1469   if (EFI_ERROR (Status)) {
1470     NET_PUT_REF (DhcpSb->LastPacket);
1471     return EFI_ACCESS_DENIED;
1472   }
1473
1474   return EFI_SUCCESS;
1475 }
1476
1477
1478 /**
1479   Each DHCP service has three timer. Two of them are count down timer.
1480   One for the packet retransmission. The other is to collect the offers.
1481   The third timer increaments the lease life which is compared to T1, T2,
1482   and lease to determine the time to renew and rebind the lease.
1483   DhcpOnTimerTick will be called once every second.
1484
1485   @param  Event                 The timer event
1486   @param  Context               The context, which is the DHCP service instance.
1487
1488   @return None
1489
1490 **/
1491 VOID
1492 EFIAPI
1493 DhcpOnTimerTick (
1494   IN EFI_EVENT              Event,
1495   IN VOID                   *Context
1496   )
1497 {
1498   DHCP_SERVICE              *DhcpSb;
1499   DHCP_PROTOCOL             *Instance;
1500   EFI_STATUS                Status;
1501
1502   DhcpSb   = (DHCP_SERVICE *) Context;
1503   Instance = DhcpSb->ActiveChild;
1504
1505   //
1506   // Check the time to wait offer
1507   //
1508   if ((DhcpSb->WaitOffer > 0) && (--DhcpSb->WaitOffer == 0)) {
1509     //
1510     // OK, offer collection finished, select a offer
1511     //
1512     ASSERT (DhcpSb->DhcpState == Dhcp4Selecting);
1513
1514     if (DhcpSb->LastOffer == NULL) {
1515       goto END_SESSION;
1516     }
1517
1518     if (EFI_ERROR (DhcpChooseOffer (DhcpSb))) {
1519       goto END_SESSION;
1520     }
1521   }
1522
1523   //
1524   // Check the retransmit timer
1525   //
1526   if ((DhcpSb->PacketToLive > 0) && (--DhcpSb->PacketToLive == 0)) {
1527
1528     if (++DhcpSb->CurRetry < DhcpSb->MaxRetries) {
1529       //
1530       // Still has another try
1531       //
1532       DhcpRetransmit (DhcpSb);
1533       DhcpSetTransmitTimer (DhcpSb);
1534
1535     } else {
1536       if (!DHCP_CONNECTED (DhcpSb->DhcpState)) {
1537         goto END_SESSION;
1538       }
1539
1540       //
1541       // Retransmission failed, if the DHCP request is initiated by
1542       // user, adjust the current state according to the lease life.
1543       // Otherwise do nothing to wait the lease to timeout
1544       //
1545       if (DhcpSb->ExtraRefresh) {
1546         Status = EFI_SUCCESS;
1547
1548         if (DhcpSb->LeaseLife < DhcpSb->T1) {
1549           Status = DhcpSetState (DhcpSb, Dhcp4Bound, FALSE);
1550
1551         } else if (DhcpSb->LeaseLife < DhcpSb->T2) {
1552           Status = DhcpSetState (DhcpSb, Dhcp4Renewing, FALSE);
1553
1554         } else if (DhcpSb->LeaseLife < DhcpSb->Lease) {
1555           Status = DhcpSetState (DhcpSb, Dhcp4Rebinding, FALSE);
1556
1557         } else {
1558           goto END_SESSION;
1559
1560         }
1561
1562         DhcpSb->IoStatus = EFI_TIMEOUT;
1563         DhcpNotifyUser (DhcpSb, DHCP_NOTIFY_RENEWREBIND);
1564       }
1565     }
1566   }
1567
1568   //
1569   // If an address has been acquired, check whether need to
1570   // refresh or whether it has expired.
1571   //
1572   if (DHCP_CONNECTED (DhcpSb->DhcpState)) {
1573     DhcpSb->LeaseLife++;
1574
1575     //
1576     // Don't timeout the lease, only count the life if user is
1577     // requesting extra renew/rebind. Adjust the state after that.
1578     //
1579     if (DhcpSb->ExtraRefresh) {
1580       return ;
1581     }
1582
1583     if (DhcpSb->LeaseLife == DhcpSb->Lease) {
1584       //
1585       // Lease expires, end the session
1586       //
1587       goto END_SESSION;
1588
1589     } else if (DhcpSb->LeaseLife == DhcpSb->T2) {
1590       //
1591       // T2 expires, transit to rebinding then send a REQUEST to any server
1592       //
1593       if (EFI_ERROR (DhcpSetState (DhcpSb, Dhcp4Rebinding, TRUE))) {
1594         goto END_SESSION;
1595       }
1596
1597       Status = DhcpSendMessage (
1598                  DhcpSb,
1599                  DhcpSb->Selected,
1600                  DhcpSb->Para,
1601                  DHCP_MSG_REQUEST,
1602                  NULL
1603                  );
1604
1605       if (EFI_ERROR (Status)) {
1606         goto END_SESSION;
1607       }
1608
1609     } else if (DhcpSb->LeaseLife == DhcpSb->T1) {
1610       //
1611       // T1 expires, transit to renewing, then send a REQUEST to the server
1612       //
1613       if (EFI_ERROR (DhcpSetState (DhcpSb, Dhcp4Renewing, TRUE))) {
1614         goto END_SESSION;
1615       }
1616
1617       Status = DhcpSendMessage (
1618                  DhcpSb,
1619                  DhcpSb->Selected,
1620                  DhcpSb->Para,
1621                  DHCP_MSG_REQUEST,
1622                  NULL
1623                  );
1624
1625       if (EFI_ERROR (Status)) {
1626         goto END_SESSION;
1627       }
1628     }
1629   }
1630
1631   //
1632   //
1633   //
1634   if ((Instance != NULL) && (Instance->Token != NULL)) {
1635     Instance->Timeout--;
1636     if (Instance->Timeout == 0) {
1637       PxeDhcpDone (Instance);
1638     }
1639   }
1640
1641   return ;
1642
1643 END_SESSION:
1644   DhcpEndSession (DhcpSb, EFI_TIMEOUT);
1645
1646   return ;
1647 }