NetworkPkg/UefiPxeBcDxe/PxeBcDhcp4.c

   1 /** @file
   2   Functions implementation related with DHCPv4 for UefiPxeBc Driver.
   3
   4   Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.<BR>
   5
   6   This program and the accompanying materials
   7   are licensed and made available under the terms and conditions of the BSD License
   8   which accompanies this distribution.  The full text of the license may be found at
   9   http://opensource.org/licenses/bsd-license.php.
  10
  11   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14 **/
  15
  16 #include "PxeBcImpl.h"
  17
  18 //
  19 // This is a map from the interested DHCP4 option tags' index to the tag value.
  20 //
  21 UINT8 mInterestedDhcp4Tags[PXEBC_DHCP4_TAG_INDEX_MAX] = {
  22   DHCP4_TAG_BOOTFILE_LEN,
  23   DHCP4_TAG_VENDOR,
  24   DHCP4_TAG_OVERLOAD,
  25   DHCP4_TAG_MSG_TYPE,
  26   DHCP4_TAG_SERVER_ID,
  27   DHCP4_TAG_VENDOR_CLASS_ID,
  28   DHCP4_TAG_BOOTFILE
  29 };
  30
  31 //
  32 // There are 4 times retries with the value of 4, 8, 16 and 32, refers to PXE2.1 spec.
  33 //
  34 UINT32 mPxeDhcpTimeout[4] = {4, 8, 16, 32};
  35
  36
  37 /**
  38   Parse a certain dhcp4 option by OptTag in Buffer, and return with start pointer.
  39
  40   @param[in]  Buffer              Pointer to the option buffer.
  41   @param[in]  Length              Length of the option buffer.
  42   @param[in]  OptTag              Tag of the required option.
  43
  44   @retval     NULL                Failed to find the required option.
  45   @retval     Others              The position of the required option.
  46
  47 **/
  48 EFI_DHCP4_PACKET_OPTION *
  49 PxeBcParseDhcp4Options (
  50   IN UINT8                      *Buffer,
  51   IN UINT32                     Length,
  52   IN UINT8                      OptTag
  53   )
  54 {
  55   EFI_DHCP4_PACKET_OPTION       *Option;
  56   UINT32                        Offset;
  57
  58   Option  = (EFI_DHCP4_PACKET_OPTION *) Buffer;
  59   Offset  = 0;
  60
  61   while (Offset < Length && Option->OpCode != DHCP4_TAG_EOP) {
  62
  63     if (Option->OpCode == OptTag) {
  64       //
  65       // Found the required option.
  66       //
  67       return Option;
  68     }
  69
  70     //
  71     // Skip the current option to the next.
  72     //
  73     if (Option->OpCode == DHCP4_TAG_PAD) {
  74       Offset++;
  75     } else {
  76       Offset += Option->Length + 2;
  77     }
  78
  79     Option = (EFI_DHCP4_PACKET_OPTION *) (Buffer + Offset);
  80   }
  81
  82   return NULL;
  83 }
  84
  85
  86 /**
  87   Parse the PXE vender options and extract the information from them.
  88
  89   @param[in]  Dhcp4Option        Pointer to vendor options in buffer.
  90   @param[in]  VendorOption       Pointer to structure to store information in vendor options.
  91
  92 **/
  93 VOID
  94 PxeBcParseVendorOptions (
  95   IN EFI_DHCP4_PACKET_OPTION    *Dhcp4Option,
  96   IN PXEBC_VENDOR_OPTION        *VendorOption
  97   )
  98 {
  99   UINT32                        *BitMap;
 100   UINT8                         VendorOptionLen;
 101   EFI_DHCP4_PACKET_OPTION       *PxeOption;
 102   UINT8                         Offset;
 103
 104   BitMap          = VendorOption->BitMap;
 105   VendorOptionLen = Dhcp4Option->Length;
 106   PxeOption       = (EFI_DHCP4_PACKET_OPTION *) &Dhcp4Option->Data[0];
 107   Offset          = 0;
 108
 109   ASSERT (PxeOption != NULL);
 110
 111   while ((Offset < VendorOptionLen) && (PxeOption->OpCode != DHCP4_TAG_EOP)) {
 112     //
 113     // Parse all the interesting PXE vendor options one by one.
 114     //
 115     switch (PxeOption->OpCode) {
 116
 117     case PXEBC_VENDOR_TAG_MTFTP_IP:
 118
 119       CopyMem (&VendorOption->MtftpIp, PxeOption->Data, sizeof (EFI_IPv4_ADDRESS));
 120       break;
 121
 122     case PXEBC_VENDOR_TAG_MTFTP_CPORT:
 123
 124       CopyMem (&VendorOption->MtftpCPort, PxeOption->Data, sizeof (VendorOption->MtftpCPort));
 125       break;
 126
 127     case PXEBC_VENDOR_TAG_MTFTP_SPORT:
 128
 129       CopyMem (&VendorOption->MtftpSPort, PxeOption->Data, sizeof (VendorOption->MtftpSPort));
 130       break;
 131
 132     case PXEBC_VENDOR_TAG_MTFTP_TIMEOUT:
 133
 134       VendorOption->MtftpTimeout = *PxeOption->Data;
 135       break;
 136
 137     case PXEBC_VENDOR_TAG_MTFTP_DELAY:
 138
 139       VendorOption->MtftpDelay = *PxeOption->Data;
 140       break;
 141
 142     case PXEBC_VENDOR_TAG_DISCOVER_CTRL:
 143
 144       VendorOption->DiscoverCtrl = *PxeOption->Data;
 145       break;
 146
 147     case PXEBC_VENDOR_TAG_DISCOVER_MCAST:
 148
 149       CopyMem (&VendorOption->DiscoverMcastIp, PxeOption->Data, sizeof (EFI_IPv4_ADDRESS));
 150       break;
 151
 152     case PXEBC_VENDOR_TAG_BOOT_SERVERS:
 153
 154       VendorOption->BootSvrLen  = PxeOption->Length;
 155       VendorOption->BootSvr     = (PXEBC_BOOT_SVR_ENTRY *) PxeOption->Data;
 156       break;
 157
 158     case PXEBC_VENDOR_TAG_BOOT_MENU:
 159
 160       VendorOption->BootMenuLen = PxeOption->Length;
 161       VendorOption->BootMenu    = (PXEBC_BOOT_MENU_ENTRY *) PxeOption->Data;
 162       break;
 163
 164     case PXEBC_VENDOR_TAG_MENU_PROMPT:
 165
 166       VendorOption->MenuPromptLen = PxeOption->Length;
 167       VendorOption->MenuPrompt    = (PXEBC_MENU_PROMPT *) PxeOption->Data;
 168       break;
 169
 170     case PXEBC_VENDOR_TAG_MCAST_ALLOC:
 171
 172       CopyMem (&VendorOption->McastIpBase, PxeOption->Data, sizeof (EFI_IPv4_ADDRESS));
 173       CopyMem (&VendorOption->McastIpBlock, PxeOption->Data + 4, sizeof (VendorOption->McastIpBlock));
 174       CopyMem (&VendorOption->McastIpRange, PxeOption->Data + 6, sizeof (VendorOption->McastIpRange));
 175       break;
 176
 177     case PXEBC_VENDOR_TAG_CREDENTIAL_TYPES:
 178
 179       VendorOption->CredTypeLen = PxeOption->Length;
 180       VendorOption->CredType    = (UINT32 *) PxeOption->Data;
 181       break;
 182
 183     case PXEBC_VENDOR_TAG_BOOT_ITEM:
 184
 185       CopyMem (&VendorOption->BootSrvType, PxeOption->Data, sizeof (VendorOption->BootSrvType));
 186       CopyMem (&VendorOption->BootSrvLayer, PxeOption->Data + 2, sizeof (VendorOption->BootSrvLayer));
 187       break;
 188
 189     default:
 190       //
 191       // Not interesting PXE vendor options.
 192       //
 193       break;
 194     }
 195
 196     //
 197     // Set the bit map for the special PXE options.
 198     //
 199     SET_VENDOR_OPTION_BIT_MAP (BitMap, PxeOption->OpCode);
 200
 201     //
 202     // Continue to the next option.
 203     //
 204     if (PxeOption->OpCode == DHCP4_TAG_PAD) {
 205       Offset++;
 206     } else {
 207       Offset = (UINT8) (Offset + PxeOption->Length + 2);
 208     }
 209
 210     PxeOption = (EFI_DHCP4_PACKET_OPTION *) (Dhcp4Option->Data + Offset);
 211   }
 212 }
 213
 214
 215 /**
 216   Build the options buffer for the DHCPv4 request packet.
 217
 218   @param[in]  Private             Pointer to PxeBc private data.
 219   @param[out] OptList             Pointer to the option pointer array.
 220   @param[in]  Buffer              Pointer to the buffer to contain the option list.
 221   @param[in]  NeedMsgType         If TRUE, it is necessary to include the Msg type option.
 222                                   Otherwise, it is not necessary.
 223
 224   @return     Index               The count of the built-in options.
 225
 226 **/
 227 UINT32
 228 PxeBcBuildDhcp4Options (
 229   IN  PXEBC_PRIVATE_DATA       *Private,
 230   OUT EFI_DHCP4_PACKET_OPTION  **OptList,
 231   IN  UINT8                    *Buffer,
 232   IN  BOOLEAN                  NeedMsgType
 233   )
 234 {
 235   UINT32                       Index;
 236   PXEBC_DHCP4_OPTION_ENTRY     OptEnt;
 237   UINT16                       Value;
 238
 239   Index      = 0;
 240   OptList[0] = (EFI_DHCP4_PACKET_OPTION *) Buffer;
 241
 242   if (NeedMsgType) {
 243     //
 244     // Append message type.
 245     //
 246     OptList[Index]->OpCode  = DHCP4_TAG_MSG_TYPE;
 247     OptList[Index]->Length  = 1;
 248     OptEnt.Mesg             = (PXEBC_DHCP4_OPTION_MESG *) OptList[Index]->Data;
 249     OptEnt.Mesg->Type       = PXEBC_DHCP4_MSG_TYPE_REQUEST;
 250     Index++;
 251     OptList[Index]          = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);
 252
 253     //
 254     // Append max message size.
 255     //
 256     OptList[Index]->OpCode  = DHCP4_TAG_MAXMSG;
 257     OptList[Index]->Length  = (UINT8) sizeof (PXEBC_DHCP4_OPTION_MAX_MESG_SIZE);
 258     OptEnt.MaxMesgSize      = (PXEBC_DHCP4_OPTION_MAX_MESG_SIZE *) OptList[Index]->Data;
 259     Value                   = NTOHS (PXEBC_DHCP4_PACKET_MAX_SIZE);
 260     CopyMem (&OptEnt.MaxMesgSize->Size, &Value, sizeof (UINT16));
 261     Index++;
 262     OptList[Index]          = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);
 263   }
 264
 265   //
 266   // Append parameter request list option.
 267   //
 268   OptList[Index]->OpCode    = DHCP4_TAG_PARA_LIST;
 269   OptList[Index]->Length    = 35;
 270   OptEnt.Para               = (PXEBC_DHCP4_OPTION_PARA *) OptList[Index]->Data;
 271   OptEnt.Para->ParaList[0]  = DHCP4_TAG_NETMASK;
 272   OptEnt.Para->ParaList[1]  = DHCP4_TAG_TIME_OFFSET;
 273   OptEnt.Para->ParaList[2]  = DHCP4_TAG_ROUTER;
 274   OptEnt.Para->ParaList[3]  = DHCP4_TAG_TIME_SERVER;
 275   OptEnt.Para->ParaList[4]  = DHCP4_TAG_NAME_SERVER;
 276   OptEnt.Para->ParaList[5]  = DHCP4_TAG_DNS_SERVER;
 277   OptEnt.Para->ParaList[6]  = DHCP4_TAG_HOSTNAME;
 278   OptEnt.Para->ParaList[7]  = DHCP4_TAG_BOOTFILE_LEN;
 279   OptEnt.Para->ParaList[8]  = DHCP4_TAG_DOMAINNAME;
 280   OptEnt.Para->ParaList[9]  = DHCP4_TAG_ROOTPATH;
 281   OptEnt.Para->ParaList[10] = DHCP4_TAG_EXTEND_PATH;
 282   OptEnt.Para->ParaList[11] = DHCP4_TAG_EMTU;
 283   OptEnt.Para->ParaList[12] = DHCP4_TAG_TTL;
 284   OptEnt.Para->ParaList[13] = DHCP4_TAG_BROADCAST;
 285   OptEnt.Para->ParaList[14] = DHCP4_TAG_NIS_DOMAIN;
 286   OptEnt.Para->ParaList[15] = DHCP4_TAG_NIS_SERVER;
 287   OptEnt.Para->ParaList[16] = DHCP4_TAG_NTP_SERVER;
 288   OptEnt.Para->ParaList[17] = DHCP4_TAG_VENDOR;
 289   OptEnt.Para->ParaList[18] = DHCP4_TAG_REQUEST_IP;
 290   OptEnt.Para->ParaList[19] = DHCP4_TAG_LEASE;
 291   OptEnt.Para->ParaList[20] = DHCP4_TAG_SERVER_ID;
 292   OptEnt.Para->ParaList[21] = DHCP4_TAG_T1;
 293   OptEnt.Para->ParaList[22] = DHCP4_TAG_T2;
 294   OptEnt.Para->ParaList[23] = DHCP4_TAG_VENDOR_CLASS_ID;
 295   OptEnt.Para->ParaList[24] = DHCP4_TAG_TFTP;
 296   OptEnt.Para->ParaList[25] = DHCP4_TAG_BOOTFILE;
 297   OptEnt.Para->ParaList[26] = DHCP4_TAG_UUID;
 298   OptEnt.Para->ParaList[27] = 0x80;
 299   OptEnt.Para->ParaList[28] = 0x81;
 300   OptEnt.Para->ParaList[29] = 0x82;
 301   OptEnt.Para->ParaList[30] = 0x83;
 302   OptEnt.Para->ParaList[31] = 0x84;
 303   OptEnt.Para->ParaList[32] = 0x85;
 304   OptEnt.Para->ParaList[33] = 0x86;
 305   OptEnt.Para->ParaList[34] = 0x87;
 306   Index++;
 307   OptList[Index]            = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);
 308
 309   //
 310   // Append UUID/Guid-based client identifier option
 311   //
 312   OptList[Index]->OpCode  = DHCP4_TAG_UUID;
 313   OptList[Index]->Length  = (UINT8) sizeof (PXEBC_DHCP4_OPTION_UUID);
 314   OptEnt.Uuid             = (PXEBC_DHCP4_OPTION_UUID *) OptList[Index]->Data;
 315   OptEnt.Uuid->Type       = 0;
 316   Index++;
 317   OptList[Index]          = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);
 318
 319   if (EFI_ERROR (NetLibGetSystemGuid ((EFI_GUID *) OptEnt.Uuid->Guid))) {
 320     //
 321     // Zero the Guid to indicate NOT programable if failed to get system Guid.
 322     //
 323     ZeroMem (OptEnt.Uuid->Guid, sizeof (EFI_GUID));
 324   }
 325
 326   //
 327   // Append client network device interface option
 328   //
 329   OptList[Index]->OpCode  = DHCP4_TAG_UNDI;
 330   OptList[Index]->Length  = (UINT8) sizeof (PXEBC_DHCP4_OPTION_UNDI);
 331   OptEnt.Undi             = (PXEBC_DHCP4_OPTION_UNDI *) OptList[Index]->Data;
 332
 333   if (Private->Nii != NULL) {
 334     OptEnt.Undi->Type     = Private->Nii->Type;
 335     OptEnt.Undi->MajorVer = Private->Nii->MajorVer;
 336     OptEnt.Undi->MinorVer = Private->Nii->MinorVer;
 337   } else {
 338     OptEnt.Undi->Type     = DEFAULT_UNDI_TYPE;
 339     OptEnt.Undi->MajorVer = DEFAULT_UNDI_MAJOR;
 340     OptEnt.Undi->MinorVer = DEFAULT_UNDI_MINOR;
 341   }
 342
 343   Index++;
 344   OptList[Index] = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);
 345
 346   //
 347   // Append client system architecture option
 348   //
 349   OptList[Index]->OpCode  = DHCP4_TAG_ARCH;
 350   OptList[Index]->Length  = (UINT8) sizeof (PXEBC_DHCP4_OPTION_ARCH);
 351   OptEnt.Arch             = (PXEBC_DHCP4_OPTION_ARCH *) OptList[Index]->Data;
 352   Value                   = HTONS (EFI_PXE_CLIENT_SYSTEM_ARCHITECTURE);
 353   CopyMem (&OptEnt.Arch->Type, &Value, sizeof (UINT16));
 354   Index++;
 355   OptList[Index]          = GET_NEXT_DHCP_OPTION (OptList[Index - 1]);
 356
 357   //
 358   // Append vendor class identify option
 359   //
 360   OptList[Index]->OpCode  = DHCP4_TAG_VENDOR_CLASS_ID;
 361   OptList[Index]->Length  = (UINT8) sizeof (PXEBC_DHCP4_OPTION_CLID);
 362   OptEnt.Clid             = (PXEBC_DHCP4_OPTION_CLID *) OptList[Index]->Data;
 363   CopyMem (
 364     OptEnt.Clid,
 365     DEFAULT_CLASS_ID_DATA,
 366     sizeof (PXEBC_DHCP4_OPTION_CLID)
 367     );
 368   PxeBcUintnToAscDecWithFormat (
 369     EFI_PXE_CLIENT_SYSTEM_ARCHITECTURE,
 370     OptEnt.Clid->ArchitectureType,
 371     sizeof (OptEnt.Clid->ArchitectureType)
 372     );
 373
 374   if (Private->Nii != NULL) {
 375     CopyMem (OptEnt.Clid->InterfaceName, Private->Nii->StringId, sizeof (OptEnt.Clid->InterfaceName));
 376     PxeBcUintnToAscDecWithFormat (Private->Nii->MajorVer, OptEnt.Clid->UndiMajor, sizeof (OptEnt.Clid->UndiMajor));
 377     PxeBcUintnToAscDecWithFormat (Private->Nii->MinorVer, OptEnt.Clid->UndiMinor, sizeof (OptEnt.Clid->UndiMinor));
 378   }
 379
 380   Index++;
 381
 382   return Index;
 383 }
 384
 385
 386 /**
 387   Create a template DHCPv4 packet as a seed.
 388
 389   @param[out] Seed           Pointer to the seed packet.
 390   @param[in]  Udp4           Pointer to EFI_UDP4_PROTOCOL.
 391
 392 **/
 393 VOID
 394 PxeBcSeedDhcp4Packet (
 395   OUT EFI_DHCP4_PACKET       *Seed,
 396   IN  EFI_UDP4_PROTOCOL      *Udp4
 397   )
 398 {
 399   EFI_SIMPLE_NETWORK_MODE    Mode;
 400   EFI_DHCP4_HEADER           *Header;
 401
 402   //
 403   // Get IfType and HwAddressSize from SNP mode data.
 404   //
 405   Udp4->GetModeData (Udp4, NULL, NULL, NULL, &Mode);
 406
 407   Seed->Size            = sizeof (EFI_DHCP4_PACKET);
 408   Seed->Length          = sizeof (Seed->Dhcp4);
 409   Header                = &Seed->Dhcp4.Header;
 410   ZeroMem (Header, sizeof (EFI_DHCP4_HEADER));
 411   Header->OpCode        = PXEBC_DHCP4_OPCODE_REQUEST;
 412   Header->HwType        = Mode.IfType;
 413   Header->HwAddrLen     = (UINT8) Mode.HwAddressSize;
 414   CopyMem (Header->ClientHwAddr, &Mode.CurrentAddress, Header->HwAddrLen);
 415
 416   Seed->Dhcp4.Magik     = PXEBC_DHCP4_MAGIC;
 417   Seed->Dhcp4.Option[0] = DHCP4_TAG_EOP;
 418 }
 419
 420
 421 /**
 422   Cache the DHCPv4 packet.
 423
 424   @param[in]  Dst          Pointer to the cache buffer for DHCPv4 packet.
 425   @param[in]  Src          Pointer to the DHCPv4 packet to be cached.
 426
 427 **/
 428 VOID
 429 PxeBcCacheDhcp4Packet (
 430   IN EFI_DHCP4_PACKET     *Dst,
 431   IN EFI_DHCP4_PACKET     *Src
 432   )
 433 {
 434   ASSERT (Dst->Size >= Src->Length);
 435
 436   CopyMem (&Dst->Dhcp4, &Src->Dhcp4, Src->Length);
 437   Dst->Length = Src->Length;
 438 }
 439
 440
 441 /**
 442   Parse the cached DHCPv4 packet, including all the options.
 443
 444   @param[in]  Cache4           Pointer to cached DHCPv4 packet.
 445
 446   @retval     EFI_SUCCESS      Parsed the DHCPv4 packet successfully.
 447   @retval     EFI_DEVICE_ERROR Failed to parse and invalid packet.
 448
 449 **/
 450 EFI_STATUS
 451 PxeBcParseDhcp4Packet (
 452   IN PXEBC_DHCP4_PACKET_CACHE    *Cache4
 453   )
 454 {
 455   EFI_DHCP4_PACKET               *Offer;
 456   EFI_DHCP4_PACKET_OPTION        **Options;
 457   EFI_DHCP4_PACKET_OPTION        *Option;
 458   PXEBC_OFFER_TYPE               OfferType;
 459   UINTN                          Index;
 460   BOOLEAN                        IsProxyOffer;
 461   BOOLEAN                        IsPxeOffer;
 462   UINT8                          *Ptr8;
 463   BOOLEAN                        FileFieldOverloaded;
 464
 465   IsProxyOffer = FALSE;
 466   IsPxeOffer   = FALSE;
 467   FileFieldOverloaded = FALSE;
 468
 469   ZeroMem (Cache4->OptList, sizeof (Cache4->OptList));
 470   ZeroMem (&Cache4->VendorOpt, sizeof (Cache4->VendorOpt));
 471
 472   Offer   = &Cache4->Packet.Offer;
 473   Options = Cache4->OptList;
 474
 475   //
 476   // Parse DHCPv4 options in this offer, and store the pointers.
 477   // First, try to parse DHCPv4 options from the DHCP optional parameters field.
 478   //
 479   for (Index = 0; Index < PXEBC_DHCP4_TAG_INDEX_MAX; Index++) {
 480     Options[Index] = PxeBcParseDhcp4Options (
 481                        Offer->Dhcp4.Option,
 482                        GET_OPTION_BUFFER_LEN (Offer),
 483                        mInterestedDhcp4Tags[Index]
 484                        );
 485   }
 486   //
 487   // Second, Check if bootfilename and serverhostname is overloaded to carry DHCP options refers to rfc-2132.
 488   // If yes, try to parse options from the BootFileName field, then ServerName field.
 489   //
 490   Option = Options[PXEBC_DHCP4_TAG_INDEX_OVERLOAD];
 491   if (Option != NULL) {
 492     if ((Option->Data[0] & PXEBC_DHCP4_OVERLOAD_FILE) != 0) {
 493       FileFieldOverloaded = TRUE;
 494       for (Index = 0; Index < PXEBC_DHCP4_TAG_INDEX_MAX; Index++) {
 495         if (Options[Index] == NULL) {
 496           Options[Index] = PxeBcParseDhcp4Options (
 497                              (UINT8 *) Offer->Dhcp4.Header.BootFileName,
 498                              sizeof (Offer->Dhcp4.Header.BootFileName),
 499                              mInterestedDhcp4Tags[Index]
 500                              );
 501         }
 502       }
 503     }
 504     if ((Option->Data[0] & PXEBC_DHCP4_OVERLOAD_SERVER_NAME) != 0) {
 505       for (Index = 0; Index < PXEBC_DHCP4_TAG_INDEX_MAX; Index++) {
 506         if (Options[Index] == NULL) {
 507           Options[Index] = PxeBcParseDhcp4Options (
 508                              (UINT8 *) Offer->Dhcp4.Header.ServerName,
 509                              sizeof (Offer->Dhcp4.Header.ServerName),
 510                              mInterestedDhcp4Tags[Index]
 511                              );
 512         }
 513       }
 514     }
 515   }
 516
 517   //
 518   // The offer with zero "yiaddr" is a proxy offer.
 519   //
 520   if (Offer->Dhcp4.Header.YourAddr.Addr[0] == 0) {
 521     IsProxyOffer = TRUE;
 522   }
 523
 524   //
 525   // The offer with "PXEClient" is a PXE offer.
 526   //
 527   Option = Options[PXEBC_DHCP4_TAG_INDEX_CLASS_ID];
 528   if ((Option != NULL) && (Option->Length >= 9) &&
 529       (CompareMem (Option->Data, DEFAULT_CLASS_ID_DATA, 9) == 0)) {
 530     IsPxeOffer = TRUE;
 531   }
 532
 533   //
 534   // Parse PXE vendor options in this offer, and store the contents/pointers.
 535   //
 536   Option = Options[PXEBC_DHCP4_TAG_INDEX_VENDOR];
 537   if (IsPxeOffer && Option != NULL) {
 538     PxeBcParseVendorOptions (Option, &Cache4->VendorOpt);
 539   }
 540
 541   //
 542   // Parse PXE boot file name:
 543   // According to PXE spec, boot file name should be read from DHCP option 67 (bootfile name) if present.
 544   // Otherwise, read from boot file field in DHCP header.
 545   //
 546   if (Options[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] != NULL) {
 547     //
 548     // RFC 2132, Section 9.5 does not strictly state Bootfile name (option 67) is null
 549     // terminated string. So force to append null terminated character at the end of string.
 550     //
 551     Ptr8 =  (UINT8*)&Options[PXEBC_DHCP4_TAG_INDEX_BOOTFILE]->Data[0];
 552     Ptr8 += Options[PXEBC_DHCP4_TAG_INDEX_BOOTFILE]->Length;
 553     if (*(Ptr8 - 1) != '\0') {
 554       *Ptr8 = '\0';
 555     }
 556   } else if (!FileFieldOverloaded && Offer->Dhcp4.Header.BootFileName[0] != 0) {
 557     //
 558     // If the bootfile is not present and bootfilename is present in DHCPv4 packet, just parse it.
 559     // Do not count dhcp option header here, or else will destroy the serverhostname.
 560     //
 561     Options[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] = (EFI_DHCP4_PACKET_OPTION *)
 562                                                 (&Offer->Dhcp4.Header.BootFileName[0] -
 563                                                 OFFSET_OF (EFI_DHCP4_PACKET_OPTION, Data[0]));
 564
 565   }
 566
 567   //
 568   // Determine offer type of the DHCPv4 packet.
 569   //
 570   Option = Options[PXEBC_DHCP4_TAG_INDEX_MSG_TYPE];
 571   if (Option == NULL || Option->Data[0] == 0) {
 572     //
 573     // It's a Bootp offer.
 574     //
 575     OfferType = PxeOfferTypeBootp;
 576
 577     Option    = Cache4->OptList[PXEBC_DHCP4_TAG_INDEX_BOOTFILE];
 578     if (Option == NULL) {
 579       //
 580       // If the Bootp offer without bootfilename, discard it.
 581       //
 582       return EFI_DEVICE_ERROR;
 583     }
 584   } else {
 585
 586     if (IS_VALID_DISCOVER_VENDOR_OPTION (Cache4->VendorOpt.BitMap)) {
 587       //
 588       // It's a PXE10 offer with PXEClient and discover vendor option.
 589       //
 590       OfferType = IsProxyOffer ? PxeOfferTypeProxyPxe10 : PxeOfferTypeDhcpPxe10;
 591     } else if (IS_VALID_MTFTP_VENDOR_OPTION (Cache4->VendorOpt.BitMap)) {
 592       //
 593       // It's a WFM11a offer with PXEClient and mtftp vendor option.
 594       // But multi-cast download is not supported currently, so discard it.
 595       //
 596       return EFI_DEVICE_ERROR;
 597     } else if (IsPxeOffer) {
 598       //
 599       // It's a BINL offer only with PXEClient.
 600       //
 601       OfferType = IsProxyOffer ? PxeOfferTypeProxyBinl : PxeOfferTypeDhcpBinl;
 602     } else {
 603       //
 604       // It's a DHCPv4 only offer, which is a pure DHCPv4 offer packet.
 605       //
 606       OfferType = PxeOfferTypeDhcpOnly;
 607     }
 608   }
 609
 610   Cache4->OfferType = OfferType;
 611
 612   return EFI_SUCCESS;
 613 }
 614
 615
 616 /**
 617   Cache the DHCPv4 ack packet, and parse it on demand.
 618
 619   @param[in]  Private             Pointer to PxeBc private data.
 620   @param[in]  Ack                 Pointer to the DHCPv4 ack packet.
 621   @param[in]  Verified            If TRUE, parse the ACK packet and store info into mode data.
 622
 623 **/
 624 VOID
 625 PxeBcCopyDhcp4Ack (
 626   IN PXEBC_PRIVATE_DATA   *Private,
 627   IN EFI_DHCP4_PACKET     *Ack,
 628   IN BOOLEAN              Verified
 629   )
 630 {
 631   EFI_PXE_BASE_CODE_MODE  *Mode;
 632
 633   Mode = Private->PxeBc.Mode;
 634
 635   PxeBcCacheDhcp4Packet (&Private->DhcpAck.Dhcp4.Packet.Ack, Ack);
 636
 637   if (Verified) {
 638     //
 639     // Parse the ack packet and store it into mode data if needed.
 640     //
 641     PxeBcParseDhcp4Packet (&Private->DhcpAck.Dhcp4);
 642     CopyMem (&Mode->DhcpAck.Dhcpv4, &Ack->Dhcp4, Ack->Length);
 643     Mode->DhcpAckReceived = TRUE;
 644   }
 645 }
 646
 647
 648 /**
 649   Cache the DHCPv4 proxy offer packet according to the received order.
 650
 651   @param[in]  Private               Pointer to PxeBc private data.
 652   @param[in]  OfferIndex            The received order of offer packets.
 653
 654 **/
 655 VOID
 656 PxeBcCopyProxyOffer (
 657   IN PXEBC_PRIVATE_DATA   *Private,
 658   IN UINT32               OfferIndex
 659   )
 660 {
 661   EFI_PXE_BASE_CODE_MODE  *Mode;
 662   EFI_DHCP4_PACKET        *Offer;
 663
 664   ASSERT (OfferIndex < Private->OfferNum);
 665   ASSERT (OfferIndex < PXEBC_OFFER_MAX_NUM);
 666
 667   Mode  = Private->PxeBc.Mode;
 668   Offer = &Private->OfferBuffer[OfferIndex].Dhcp4.Packet.Offer;
 669
 670   //
 671   // Cache the proxy offer packet and parse it.
 672   //
 673   PxeBcCacheDhcp4Packet (&Private->ProxyOffer.Dhcp4.Packet.Offer, Offer);
 674   PxeBcParseDhcp4Packet (&Private->ProxyOffer.Dhcp4);
 675
 676   //
 677   // Store this packet into mode data.
 678   //
 679   CopyMem (&Mode->ProxyOffer.Dhcpv4, &Offer->Dhcp4, Offer->Length);
 680   Mode->ProxyOfferReceived = TRUE;
 681 }
 682
 683
 684 /**
 685   Retry to request bootfile name by the BINL offer.
 686
 687   @param[in]  Private              Pointer to PxeBc private data.
 688   @param[in]  Index                The received order of offer packets.
 689
 690   @retval     EFI_SUCCESS          Successfully retried to request bootfile name.
 691   @retval     EFI_DEVICE_ERROR     Failed to retry bootfile name.
 692
 693 **/
 694 EFI_STATUS
 695 PxeBcRetryBinlOffer (
 696   IN PXEBC_PRIVATE_DATA     *Private,
 697   IN UINT32                 Index
 698   )
 699 {
 700   EFI_DHCP4_PACKET          *Offer;
 701   EFI_IP_ADDRESS            ServerIp;
 702   EFI_STATUS                Status;
 703   PXEBC_DHCP4_PACKET_CACHE  *Cache4;
 704   EFI_DHCP4_PACKET          *Reply;
 705
 706   ASSERT (Index < PXEBC_OFFER_MAX_NUM);
 707   ASSERT (Private->OfferBuffer[Index].Dhcp4.OfferType == PxeOfferTypeDhcpBinl ||
 708           Private->OfferBuffer[Index].Dhcp4.OfferType == PxeOfferTypeProxyBinl);
 709
 710   Offer = &Private->OfferBuffer[Index].Dhcp4.Packet.Offer;
 711
 712   //
 713   // Prefer to siaddr in header as next server address. If it's zero, then use option 54.
 714   //
 715   if (Offer->Dhcp4.Header.ServerAddr.Addr[0] == 0) {
 716     CopyMem (
 717       &ServerIp.Addr[0],
 718       Private->OfferBuffer[Index].Dhcp4.OptList[PXEBC_DHCP4_TAG_INDEX_SERVER_ID]->Data,
 719       sizeof (EFI_IPv4_ADDRESS)
 720       );
 721   } else {
 722     CopyMem (
 723       &ServerIp.Addr[0],
 724       &Offer->Dhcp4.Header.ServerAddr,
 725       sizeof (EFI_IPv4_ADDRESS)
 726       );
 727   }
 728
 729   Private->IsDoDiscover = FALSE;
 730   Cache4                = &Private->ProxyOffer.Dhcp4;
 731   Reply                 = &Cache4->Packet.Offer;
 732
 733   //
 734   // Send another request packet for bootfile name.
 735   //
 736   Status = PxeBcDhcp4Discover (
 737              Private,
 738              0,
 739              NULL,
 740              FALSE,
 741              &ServerIp,
 742              0,
 743              NULL
 744              );
 745   if (EFI_ERROR (Status)) {
 746     return Status;
 747   }
 748
 749   //
 750   // Parse the reply for the last request packet.
 751   //
 752   Status = PxeBcParseDhcp4Packet (Cache4);
 753   if (EFI_ERROR (Status)) {
 754     return Status;
 755   }
 756
 757   if (Cache4->OfferType != PxeOfferTypeProxyPxe10 &&
 758       Cache4->OfferType != PxeOfferTypeProxyWfm11a &&
 759       Cache4->OptList[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] == NULL) {
 760     //
 761     // This BINL ack doesn't have discovery option set or multicast option set
 762     // or bootfile name specified.
 763     //
 764     return EFI_DEVICE_ERROR;
 765   }
 766
 767   //
 768   // Store the reply into mode data.
 769   //
 770   Private->PxeBc.Mode->ProxyOfferReceived = TRUE;
 771   CopyMem (&Private->PxeBc.Mode->ProxyOffer.Dhcpv4, &Reply->Dhcp4, Reply->Length);
 772
 773   return EFI_SUCCESS;
 774 }
 775
 776
 777 /**
 778   Cache all the received DHCPv4 offers, and set OfferIndex and OfferCount.
 779
 780   @param[in]  Private               Pointer to PxeBc private data.
 781   @param[in]  RcvdOffer             Pointer to the received offer packet.
 782
 783 **/
 784 VOID
 785 PxeBcCacheDhcp4Offer (
 786   IN PXEBC_PRIVATE_DATA     *Private,
 787   IN EFI_DHCP4_PACKET       *RcvdOffer
 788   )
 789 {
 790   PXEBC_DHCP4_PACKET_CACHE  *Cache4;
 791   EFI_DHCP4_PACKET          *Offer;
 792   PXEBC_OFFER_TYPE          OfferType;
 793
 794   ASSERT (Private->OfferNum < PXEBC_OFFER_MAX_NUM);
 795   Cache4 = &Private->OfferBuffer[Private->OfferNum].Dhcp4;
 796   Offer  = &Cache4->Packet.Offer;
 797
 798   //
 799   // Cache the content of DHCPv4 packet firstly.
 800   //
 801   PxeBcCacheDhcp4Packet (Offer, RcvdOffer);
 802
 803   //
 804   // Validate the DHCPv4 packet, and parse the options and offer type.
 805   //
 806   if (EFI_ERROR (PxeBcParseDhcp4Packet (Cache4))) {
 807     return;
 808   }
 809
 810   //
 811   // Determine whether cache the current offer by type, and record OfferIndex and OfferCount.
 812   //
 813   OfferType = Cache4->OfferType;
 814   ASSERT (OfferType < PxeOfferTypeMax);
 815
 816   if (OfferType == PxeOfferTypeBootp) {
 817     //
 818     // It's a Bootp offer, only cache the first one, and discard the others.
 819     //
 820     if (Private->OfferCount[OfferType] == 0) {
 821       Private->OfferIndex[OfferType][0] = Private->OfferNum;
 822       Private->OfferCount[OfferType]    = 1;
 823     } else {
 824       return;
 825     }
 826   } else {
 827     ASSERT (Private->OfferCount[OfferType] < PXEBC_OFFER_MAX_NUM);
 828     if (IS_PROXY_DHCP_OFFER (Offer)) {
 829       //
 830       // It's a proxy offer without yiaddr, including PXE10, WFM11a or BINL offer.
 831       //
 832       Private->IsProxyRecved = TRUE;
 833
 834       if (OfferType == PxeOfferTypeProxyBinl) {
 835         //
 836         // Cache all proxy BINL offers.
 837         //
 838         Private->OfferIndex[OfferType][Private->OfferCount[OfferType]] = Private->OfferNum;
 839         Private->OfferCount[OfferType]++;
 840       } else if (Private->OfferCount[OfferType] > 0) {
 841         //
 842         // Only cache the first PXE10/WFM11a offer, and discard the others.
 843         //
 844         Private->OfferIndex[OfferType][0] = Private->OfferNum;
 845         Private->OfferCount[OfferType]    = 1;
 846       } else {
 847         return ;
 848       }
 849     } else {
 850       //
 851       // It's a DHCPv4 offer with yiaddr, and cache them all.
 852       //
 853       Private->OfferIndex[OfferType][Private->OfferCount[OfferType]] = Private->OfferNum;
 854       Private->OfferCount[OfferType]++;
 855     }
 856   }
 857
 858   Private->OfferNum++;
 859 }
 860
 861
 862 /**
 863   Select an DHCPv4 offer, and record SelectIndex and SelectProxyType.
 864
 865   @param[in]  Private             Pointer to PxeBc private data.
 866
 867 **/
 868 VOID
 869 PxeBcSelectDhcp4Offer (
 870   IN PXEBC_PRIVATE_DATA       *Private
 871   )
 872 {
 873   UINT32                      Index;
 874   UINT32                      OfferIndex;
 875   EFI_DHCP4_PACKET            *Offer;
 876
 877   Private->SelectIndex = 0;
 878
 879   if (Private->IsOfferSorted) {
 880     //
 881     // Select offer by default policy.
 882     //
 883     if (Private->OfferCount[PxeOfferTypeDhcpPxe10] > 0) {
 884       //
 885       // 1. DhcpPxe10 offer
 886       //
 887       Private->SelectIndex = Private->OfferIndex[PxeOfferTypeDhcpPxe10][0] + 1;
 888
 889     } else if (Private->OfferCount[PxeOfferTypeDhcpWfm11a] > 0) {
 890       //
 891       // 2. DhcpWfm11a offer
 892       //
 893       Private->SelectIndex = Private->OfferIndex[PxeOfferTypeDhcpWfm11a][0] + 1;
 894
 895     } else if (Private->OfferCount[PxeOfferTypeDhcpOnly] > 0 &&
 896                Private->OfferCount[PxeOfferTypeProxyPxe10] > 0) {
 897       //
 898       // 3. DhcpOnly offer and ProxyPxe10 offer.
 899       //
 900       Private->SelectIndex     = Private->OfferIndex[PxeOfferTypeDhcpOnly][0] + 1;
 901       Private->SelectProxyType = PxeOfferTypeProxyPxe10;
 902
 903     } else if (Private->OfferCount[PxeOfferTypeDhcpOnly] > 0 &&
 904                Private->OfferCount[PxeOfferTypeProxyWfm11a] > 0) {
 905       //
 906       // 4. DhcpOnly offer and ProxyWfm11a offer.
 907       //
 908       Private->SelectIndex     = Private->OfferIndex[PxeOfferTypeDhcpOnly][0] + 1;
 909       Private->SelectProxyType = PxeOfferTypeProxyWfm11a;
 910
 911     } else if (Private->OfferCount[PxeOfferTypeDhcpBinl] > 0) {
 912       //
 913       // 5. DhcpBinl offer.
 914       //
 915       Private->SelectIndex = Private->OfferIndex[PxeOfferTypeDhcpBinl][0] + 1;
 916
 917     } else if (Private->OfferCount[PxeOfferTypeDhcpOnly] > 0 &&
 918                Private->OfferCount[PxeOfferTypeProxyBinl] > 0) {
 919       //
 920       // 6. DhcpOnly offer and ProxyBinl offer.
 921       //
 922       Private->SelectIndex     = Private->OfferIndex[PxeOfferTypeDhcpOnly][0] + 1;
 923       Private->SelectProxyType = PxeOfferTypeProxyBinl;
 924
 925     } else {
 926       //
 927       // 7. DhcpOnly offer with bootfilename.
 928       //
 929       for (Index = 0; Index < Private->OfferCount[PxeOfferTypeDhcpOnly]; Index++) {
 930         OfferIndex = Private->OfferIndex[PxeOfferTypeDhcpOnly][Index];
 931         if (Private->OfferBuffer[OfferIndex].Dhcp4.OptList[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] != NULL) {
 932           Private->SelectIndex = OfferIndex + 1;
 933           break;
 934         }
 935       }
 936       //
 937       // 8. Bootp offer with bootfilename.
 938       //
 939       OfferIndex = Private->OfferIndex[PxeOfferTypeBootp][0];
 940       if (Private->SelectIndex == 0 &&
 941           Private->OfferCount[PxeOfferTypeBootp] > 0 &&
 942           Private->OfferBuffer[OfferIndex].Dhcp4.OptList[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] != NULL) {
 943         Private->SelectIndex = OfferIndex + 1;
 944       }
 945     }
 946   } else {
 947     //
 948     // Select offer by received order.
 949     //
 950     for (Index = 0; Index < Private->OfferNum; Index++) {
 951
 952       Offer = &Private->OfferBuffer[Index].Dhcp4.Packet.Offer;
 953
 954       if (IS_PROXY_DHCP_OFFER (Offer)) {
 955         //
 956         // Skip proxy offers
 957         //
 958         continue;
 959       }
 960
 961       if (!Private->IsProxyRecved &&
 962           Private->OfferBuffer[Index].Dhcp4.OfferType == PxeOfferTypeDhcpOnly &&
 963           Private->OfferBuffer[Index].Dhcp4.OptList[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] == NULL) {
 964         //
 965         // Skip if DhcpOnly offer without any other proxy offers or bootfilename.
 966         //
 967         continue;
 968       }
 969
 970       //
 971       // Record the index of the select offer.
 972       //
 973       Private->SelectIndex = Index + 1;
 974       break;
 975     }
 976   }
 977 }
 978
 979
 980 /**
 981   Handle the DHCPv4 offer packet.
 982
 983   @param[in]  Private             Pointer to PxeBc private data.
 984
 985   @retval     EFI_SUCCESS         Handled the DHCPv4 offer packet successfully.
 986   @retval     EFI_NO_RESPONSE     No response to the following request packet.
 987   @retval     EFI_NOT_FOUND       No boot filename received.
 988
 989 **/
 990 EFI_STATUS
 991 PxeBcHandleDhcp4Offer (
 992   IN PXEBC_PRIVATE_DATA     *Private
 993   )
 994 {
 995   PXEBC_DHCP4_PACKET_CACHE  *Cache4;
 996   EFI_DHCP4_PACKET_OPTION   **Options;
 997   UINT32                    Index;
 998   EFI_DHCP4_PACKET          *Offer;
 999   PXEBC_OFFER_TYPE          OfferType;
1000   UINT32                    ProxyIndex;
1001   UINT32                    SelectIndex;
1002   EFI_STATUS                Status;
1003   EFI_PXE_BASE_CODE_MODE    *Mode;
1004   EFI_DHCP4_PACKET          *Ack;
1005
1006   ASSERT (Private->SelectIndex > 0);
1007   SelectIndex = (UINT32) (Private->SelectIndex - 1);
1008   ASSERT (SelectIndex < PXEBC_OFFER_MAX_NUM);
1009   Cache4      = &Private->OfferBuffer[SelectIndex].Dhcp4;
1010   Options     = Cache4->OptList;
1011   Status      = EFI_SUCCESS;
1012
1013   if (Cache4->OfferType == PxeOfferTypeDhcpBinl) {
1014     //
1015     // DhcpBinl offer is selected, so need try to request bootfilename by this offer.
1016     //
1017     if (EFI_ERROR (PxeBcRetryBinlOffer (Private, SelectIndex))) {
1018       Status = EFI_NO_RESPONSE;
1019     }
1020   } else if (Cache4->OfferType == PxeOfferTypeDhcpOnly) {
1021
1022     if (Private->IsProxyRecved) {
1023       //
1024       // DhcpOnly offer is selected, so need try to request bootfile name.
1025       //
1026       ProxyIndex = 0;
1027       if (Private->IsOfferSorted) {
1028         //
1029         // The proxy offer should be determined if select by default policy.
1030         // IsOfferSorted means all offers are labeled by OfferIndex.
1031         //
1032         ASSERT (Private->SelectProxyType < PxeOfferTypeMax);
1033         ASSERT (Private->OfferCount[Private->SelectProxyType] > 0);
1034
1035         if (Private->SelectProxyType == PxeOfferTypeProxyBinl) {
1036           //
1037           // Try all the cached ProxyBinl offer one by one to request bootfile name.
1038           //
1039           for (Index = 0; Index < Private->OfferCount[Private->SelectProxyType]; Index++) {
1040             ASSERT (Index < PXEBC_OFFER_MAX_NUM);
1041             ProxyIndex = Private->OfferIndex[Private->SelectProxyType][Index];
1042             if (!EFI_ERROR (PxeBcRetryBinlOffer (Private, ProxyIndex))) {
1043               break;
1044             }
1045           }
1046           if (Index == Private->OfferCount[Private->SelectProxyType]) {
1047             Status = EFI_NO_RESPONSE;
1048           }
1049         } else {
1050           //
1051           // For other proxy offers, only one is buffered.
1052           //
1053           ProxyIndex = Private->OfferIndex[Private->SelectProxyType][0];
1054         }
1055       } else {
1056         //
1057         // The proxy offer should not be determined if select by received order.
1058         //
1059         Status = EFI_NO_RESPONSE;
1060
1061         for (Index = 0; Index < Private->OfferNum; Index++) {
1062           ASSERT (Index < PXEBC_OFFER_MAX_NUM);
1063           Offer     = &Private->OfferBuffer[Index].Dhcp4.Packet.Offer;
1064           OfferType = Private->OfferBuffer[Index].Dhcp4.OfferType;
1065           if (!IS_PROXY_DHCP_OFFER (Offer)) {
1066             //
1067             // Skip non proxy DHCPv4 offers.
1068             //
1069             continue;
1070           }
1071
1072           if (OfferType == PxeOfferTypeProxyBinl) {
1073             //
1074             // Try all the cached ProxyBinl offer one by one to request bootfile name.
1075             //
1076             if (EFI_ERROR (PxeBcRetryBinlOffer (Private, Index))) {
1077               continue;
1078             }
1079           }
1080
1081           Private->SelectProxyType = OfferType;
1082           ProxyIndex               = Index;
1083           Status                   = EFI_SUCCESS;
1084           break;
1085         }
1086       }
1087
1088       if (!EFI_ERROR (Status) && Private->SelectProxyType != PxeOfferTypeProxyBinl) {
1089         //
1090         // Success to try to request by a ProxyPxe10 or ProxyWfm11a offer, copy and parse it.
1091         //
1092         PxeBcCopyProxyOffer (Private, ProxyIndex);
1093       }
1094     } else {
1095       //
1096       //  Othewise, the bootfile name must be included in DhcpOnly offer.
1097       //
1098       if (Options[PXEBC_DHCP4_TAG_INDEX_BOOTFILE] == NULL) {
1099         Status = EFI_NOT_FOUND;
1100       }
1101     }
1102   }
1103
1104   if (!EFI_ERROR (Status)) {
1105     //
1106     // All PXE boot information is ready by now.
1107     //
1108     Mode  = Private->PxeBc.Mode;
1109     Offer = &Cache4->Packet.Offer;
1110     Ack   = &Private->DhcpAck.Dhcp4.Packet.Ack;
1111     if (Cache4->OfferType == PxeOfferTypeBootp) {
1112       //
1113       // Bootp is a special case that only 2 packets involved instead of 4. So the bootp's reply
1114       // should be taken as ack.
1115       //
1116       Ack = Offer;
1117     }
1118
1119     PxeBcCopyDhcp4Ack (Private, Ack, TRUE);
1120     Mode->DhcpDiscoverValid = TRUE;
1121   }
1122
1123   return Status;
1124 }
1125
1126
1127 /**
1128   EFI_DHCP4_CALLBACK is provided by the consumer of the EFI DHCPv4 Protocol driver
1129   to intercept events that occurred in the configuration process.
1130
1131   @param[in]  This              Pointer to the EFI DHCPv4 Protocol.
1132   @param[in]  Context           Pointer to the context set by EFI_DHCP4_PROTOCOL.Configure().
1133   @param[in]  CurrentState      The current operational state of the EFI DHCPv4 Protocol driver.
1134   @param[in]  Dhcp4Event        The event that occurs in the current state, which usually means a
1135                                 state transition.
1136   @param[in]  Packet            The DHCPv4 packet that is going to be sent or already received.
1137   @param[out] NewPacket         The packet that is used to replace the above Packet.
1138
1139   @retval EFI_SUCCESS           Tells the EFI DHCPv4 Protocol driver to continue the DHCP process.
1140   @retval EFI_NOT_READY         Only used in the Dhcp4Selecting state. The EFI DHCPv4 Protocol
1141                                 driver will continue to wait for more DHCPOFFER packets until the
1142                                 retry timeout expires.
1143   @retval EFI_ABORTED           Tells the EFI DHCPv4 Protocol driver to abort the current process
1144                                 and return to the Dhcp4Init or Dhcp4InitReboot state.
1145
1146 **/
1147 EFI_STATUS
1148 EFIAPI
1149 PxeBcDhcp4CallBack (
1150   IN  EFI_DHCP4_PROTOCOL               *This,
1151   IN  VOID                             *Context,
1152   IN  EFI_DHCP4_STATE                  CurrentState,
1153   IN  EFI_DHCP4_EVENT                  Dhcp4Event,
1154   IN  EFI_DHCP4_PACKET                 *Packet            OPTIONAL,
1155   OUT EFI_DHCP4_PACKET                 **NewPacket        OPTIONAL
1156   )
1157 {
1158   PXEBC_PRIVATE_DATA                   *Private;
1159   EFI_PXE_BASE_CODE_MODE               *Mode;
1160   EFI_PXE_BASE_CODE_CALLBACK_PROTOCOL  *Callback;
1161   EFI_DHCP4_PACKET_OPTION              *MaxMsgSize;
1162   UINT16                               Value;
1163   EFI_STATUS                           Status;
1164   BOOLEAN                              Received;
1165
1166   if ((Dhcp4Event != Dhcp4RcvdOffer) &&
1167       (Dhcp4Event != Dhcp4SelectOffer) &&
1168       (Dhcp4Event != Dhcp4SendDiscover) &&
1169       (Dhcp4Event != Dhcp4RcvdAck)) {
1170     return EFI_SUCCESS;
1171   }
1172
1173   Private   = (PXEBC_PRIVATE_DATA *) Context;
1174   Mode      = Private->PxeBc.Mode;
1175   Callback  = Private->PxeBcCallback;
1176
1177   //
1178   // Override the Maximum DHCP Message Size.
1179   //
1180   MaxMsgSize = PxeBcParseDhcp4Options (
1181                  Packet->Dhcp4.Option,
1182                  GET_OPTION_BUFFER_LEN (Packet),
1183                  DHCP4_TAG_MAXMSG
1184                  );
1185   if (MaxMsgSize != NULL) {
1186     Value = HTONS (PXEBC_DHCP4_PACKET_MAX_SIZE);
1187     CopyMem (MaxMsgSize->Data, &Value, sizeof (Value));
1188   }
1189
1190   //
1191   // Callback to user if any packets sent or received.
1192   //
1193   if (Dhcp4Event != Dhcp4SelectOffer && Callback != NULL) {
1194     Received = (BOOLEAN) (Dhcp4Event == Dhcp4RcvdOffer || Dhcp4Event == Dhcp4RcvdAck);
1195     Status = Callback->Callback (
1196                          Callback,
1197                          Private->Function,
1198                          Received,
1199                          Packet->Length,
1200                          (EFI_PXE_BASE_CODE_PACKET *) &Packet->Dhcp4
1201                          );
1202     if (Status != EFI_PXE_BASE_CODE_CALLBACK_STATUS_CONTINUE) {
1203       return EFI_ABORTED;
1204     }
1205   }
1206
1207   Status = EFI_SUCCESS;
1208
1209   switch (Dhcp4Event) {
1210
1211   case Dhcp4SendDiscover:
1212     if (Packet->Length > PXEBC_DHCP4_PACKET_MAX_SIZE) {
1213       //
1214       // If the to be sent packet exceeds the maximum length, abort the DHCP process.
1215       //
1216       Status = EFI_ABORTED;
1217       break;
1218     }
1219
1220     //
1221     // Cache the DHCPv4 discover packet to mode data directly.
1222     // It need to check SendGuid as well as Dhcp4SendRequest.
1223     //
1224     CopyMem (&Mode->DhcpDiscover.Dhcpv4, &Packet->Dhcp4, Packet->Length);
1225
1226   case Dhcp4SendRequest:
1227     if (Packet->Length > PXEBC_DHCP4_PACKET_MAX_SIZE) {
1228       //
1229       // If the to be sent packet exceeds the maximum length, abort the DHCP process.
1230       //
1231       Status = EFI_ABORTED;
1232       break;
1233     }
1234
1235     if (Mode->SendGUID) {
1236       //
1237       // Send the system Guid instead of the MAC address as the hardware address if required.
1238       //
1239       if (EFI_ERROR (NetLibGetSystemGuid ((EFI_GUID *) Packet->Dhcp4.Header.ClientHwAddr))) {
1240         //
1241         // Zero the Guid to indicate NOT programable if failed to get system Guid.
1242         //
1243         ZeroMem (Packet->Dhcp4.Header.ClientHwAddr, sizeof (EFI_GUID));
1244       }
1245       Packet->Dhcp4.Header.HwAddrLen = (UINT8) sizeof (EFI_GUID);
1246     }
1247     break;
1248
1249   case Dhcp4RcvdOffer:
1250     Status = EFI_NOT_READY;
1251     if (Packet->Length > PXEBC_DHCP4_PACKET_MAX_SIZE) {
1252       //
1253       // Ignore the incoming packets which exceed the maximum length.
1254       //
1255       break;
1256     }
1257     if (Private->OfferNum < PXEBC_OFFER_MAX_NUM) {
1258       //
1259       // Cache the DHCPv4 offers to OfferBuffer[] for select later, and record
1260       // the OfferIndex and OfferCount.
1261       //
1262       PxeBcCacheDhcp4Offer (Private, Packet);
1263     }
1264     break;
1265
1266   case Dhcp4SelectOffer:
1267     //
1268     // Select offer by the default policy or by order, and record the SelectIndex
1269     // and SelectProxyType.
1270     //
1271     PxeBcSelectDhcp4Offer (Private);
1272
1273     if (Private->SelectIndex == 0) {
1274       Status = EFI_ABORTED;
1275     } else {
1276       *NewPacket = &Private->OfferBuffer[Private->SelectIndex - 1].Dhcp4.Packet.Offer;
1277     }
1278     break;
1279
1280   case Dhcp4RcvdAck:
1281     if (Packet->Length > PXEBC_DHCP4_PACKET_MAX_SIZE) {
1282       //
1283       // Abort the DHCP if the ACK packet exceeds the maximum length.
1284       //
1285           Status = EFI_ABORTED;
1286           break;
1287     }
1288
1289     //
1290     // Cache the DHCPv4 ack to Private->Dhcp4Ack, but it's not the final ack in mode data
1291     // without verification.
1292     //
1293     ASSERT (Private->SelectIndex != 0);
1294
1295     PxeBcCopyDhcp4Ack (Private, Packet, FALSE);
1296     break;
1297
1298   default:
1299     break;
1300   }
1301
1302   return Status;
1303 }
1304
1305
1306 /**
1307   Build and send out the request packet for the bootfile, and parse the reply.
1308
1309   @param[in]  Private               Pointer to PxeBc private data.
1310   @param[in]  Type                  PxeBc option boot item type.
1311   @param[in]  Layer                 Pointer to option boot item layer.
1312   @param[in]  UseBis                Use BIS or not.
1313   @param[in]  DestIp                Pointer to the server address.
1314   @param[in]  IpCount               The total count of the server address.
1315   @param[in]  SrvList               Pointer to EFI_PXE_BASE_CODE_SRVLIST.
1316
1317   @retval     EFI_SUCCESS           Successfully discovered boot file.
1318   @retval     EFI_OUT_OF_RESOURCES  Failed to allocate resource.
1319   @retval     EFI_NOT_FOUND         Can't get the PXE reply packet.
1320   @retval     Others                Failed to discover boot file.
1321
1322 **/
1323 EFI_STATUS
1324 PxeBcDhcp4Discover (
1325   IN  PXEBC_PRIVATE_DATA              *Private,
1326   IN  UINT16                          Type,
1327   IN  UINT16                          *Layer,
1328   IN  BOOLEAN                         UseBis,
1329   IN  EFI_IP_ADDRESS                  *DestIp,
1330   IN  UINT16                          IpCount,
1331   IN  EFI_PXE_BASE_CODE_SRVLIST       *SrvList
1332   )
1333 {
1334   EFI_PXE_BASE_CODE_UDP_PORT          Sport;
1335   EFI_PXE_BASE_CODE_MODE              *Mode;
1336   EFI_DHCP4_PROTOCOL                  *Dhcp4;
1337   EFI_DHCP4_TRANSMIT_RECEIVE_TOKEN    Token;
1338   BOOLEAN                             IsBCast;
1339   EFI_STATUS                          Status;
1340   UINT16                              RepIndex;
1341   UINT16                              SrvIndex;
1342   UINT16                              TryIndex;
1343   EFI_DHCP4_LISTEN_POINT              ListenPoint;
1344   EFI_DHCP4_PACKET                    *Response;
1345   UINT8                               Buffer[PXEBC_DHCP4_OPTION_MAX_SIZE];
1346   EFI_DHCP4_PACKET_OPTION             *OptList[PXEBC_DHCP4_OPTION_MAX_NUM];
1347   UINT32                              OptCount;
1348   EFI_DHCP4_PACKET_OPTION             *PxeOpt;
1349   PXEBC_OPTION_BOOT_ITEM              *PxeBootItem;
1350   UINT8                               VendorOptLen;
1351   UINT32                              Xid;
1352
1353   Mode      = Private->PxeBc.Mode;
1354   Dhcp4     = Private->Dhcp4;
1355   Status    = EFI_SUCCESS;
1356
1357   ZeroMem (&Token, sizeof (EFI_DHCP4_TRANSMIT_RECEIVE_TOKEN));
1358
1359   //
1360   // Use broadcast if destination address not specified.
1361   //
1362   if (DestIp == NULL) {
1363     Sport   = PXEBC_DHCP4_S_PORT;
1364     IsBCast = TRUE;
1365   } else {
1366     Sport   = PXEBC_BS_DISCOVER_PORT;
1367     IsBCast = FALSE;
1368   }
1369
1370   if (!UseBis && Layer != NULL) {
1371     *Layer &= EFI_PXE_BASE_CODE_BOOT_LAYER_MASK;
1372   }
1373
1374   //
1375   // Build all the options for the request packet.
1376   //
1377   OptCount = PxeBcBuildDhcp4Options (Private, OptList, Buffer, TRUE);
1378
1379   if (Private->IsDoDiscover) {
1380     //
1381     // Add vendor option of PXE_BOOT_ITEM
1382     //
1383     VendorOptLen      = (UINT8) ((sizeof (EFI_DHCP4_PACKET_OPTION) - 1) * 2 + sizeof (PXEBC_OPTION_BOOT_ITEM) + 1);
1384     OptList[OptCount] = AllocateZeroPool (VendorOptLen);
1385     if (OptList[OptCount] == NULL) {
1386       return EFI_OUT_OF_RESOURCES;
1387     }
1388
1389     OptList[OptCount]->OpCode     = DHCP4_TAG_VENDOR;
1390     OptList[OptCount]->Length     = (UINT8) (VendorOptLen - 2);
1391     PxeOpt                        = (EFI_DHCP4_PACKET_OPTION *) OptList[OptCount]->Data;
1392     PxeOpt->OpCode                = PXEBC_VENDOR_TAG_BOOT_ITEM;
1393     PxeOpt->Length                = (UINT8) sizeof (PXEBC_OPTION_BOOT_ITEM);
1394     PxeBootItem                   = (PXEBC_OPTION_BOOT_ITEM *) PxeOpt->Data;
1395     PxeBootItem->Type             = HTONS (Type);
1396     PxeOpt->Data[PxeOpt->Length]  = DHCP4_TAG_EOP;
1397
1398     if (Layer != NULL) {
1399       PxeBootItem->Layer          = HTONS (*Layer);
1400     }
1401
1402     OptCount++;
1403   }
1404
1405   //
1406   // Build the request packet with seed packet and option list.
1407   //
1408   Status = Dhcp4->Build (
1409                     Dhcp4,
1410                     &Private->SeedPacket,
1411                     0,
1412                     NULL,
1413                     OptCount,
1414                     OptList,
1415                     &Token.Packet
1416                     );
1417   //
1418   // Free the vendor option of PXE_BOOT_ITEM.
1419   //
1420   if (Private->IsDoDiscover) {
1421     FreePool (OptList[OptCount - 1]);
1422   }
1423
1424   if (EFI_ERROR (Status)) {
1425     return Status;
1426   }
1427
1428   if (Mode->SendGUID) {
1429     if (EFI_ERROR (NetLibGetSystemGuid ((EFI_GUID *) Token.Packet->Dhcp4.Header.ClientHwAddr))) {
1430       //
1431       // Zero the Guid to indicate NOT programable if failed to get system Guid.
1432       //
1433       ZeroMem (Token.Packet->Dhcp4.Header.ClientHwAddr, sizeof (EFI_GUID));
1434     }
1435     Token.Packet->Dhcp4.Header.HwAddrLen = (UINT8)  sizeof (EFI_GUID);
1436   }
1437
1438   //
1439   // Set fields of the token for the request packet.
1440   //
1441   Xid                                 = NET_RANDOM (NetRandomInitSeed ());
1442   Token.Packet->Dhcp4.Header.Xid      = HTONL (Xid);
1443   Token.Packet->Dhcp4.Header.Reserved = HTONS ((UINT16) ((IsBCast) ? 0x8000 : 0x0));
1444   CopyMem (&Token.Packet->Dhcp4.Header.ClientAddr, &Private->StationIp, sizeof (EFI_IPv4_ADDRESS));
1445
1446   Token.RemotePort = Sport;
1447
1448   if (IsBCast) {
1449     SetMem (&Token.RemoteAddress, sizeof (EFI_IPv4_ADDRESS), 0xff);
1450   } else {
1451     CopyMem (&Token.RemoteAddress, DestIp, sizeof (EFI_IPv4_ADDRESS));
1452   }
1453
1454   CopyMem (&Token.GatewayAddress, &Private->GatewayIp, sizeof (EFI_IPv4_ADDRESS));
1455
1456   if (!IsBCast) {
1457     Token.ListenPointCount            = 1;
1458     Token.ListenPoints                = &ListenPoint;
1459     Token.ListenPoints[0].ListenPort  = PXEBC_BS_DISCOVER_PORT;
1460     CopyMem (&Token.ListenPoints[0].ListenAddress, &Private->StationIp, sizeof(EFI_IPv4_ADDRESS));
1461     CopyMem (&Token.ListenPoints[0].SubnetMask, &Private->SubnetMask, sizeof(EFI_IPv4_ADDRESS));
1462   }
1463
1464   //
1465   // Send out the request packet to discover the bootfile.
1466   //
1467   for (TryIndex = 1; TryIndex <= PXEBC_BOOT_REQUEST_RETRIES; TryIndex++) {
1468
1469     Token.TimeoutValue                  = (UINT16) (PXEBC_BOOT_REQUEST_TIMEOUT * TryIndex);
1470     Token.Packet->Dhcp4.Header.Seconds  = (UINT16) (PXEBC_BOOT_REQUEST_TIMEOUT * (TryIndex - 1));
1471
1472     Status = Dhcp4->TransmitReceive (Dhcp4, &Token);
1473     if (Token.Status != EFI_TIMEOUT) {
1474       break;
1475     }
1476   }
1477
1478   if (TryIndex > PXEBC_BOOT_REQUEST_RETRIES) {
1479     //
1480     // No server response our PXE request
1481     //
1482     Status = EFI_TIMEOUT;
1483   }
1484
1485   if (!EFI_ERROR (Status)) {
1486
1487     RepIndex  = 0;
1488     SrvIndex  = 0;
1489     Response  = Token.ResponseList;
1490     //
1491     // Find the right PXE Reply according to server address.
1492     //
1493     while (RepIndex < Token.ResponseCount) {
1494
1495       while (SrvIndex < IpCount) {
1496         if (SrvList[SrvIndex].AcceptAnyResponse) {
1497           break;
1498         }
1499         if ((SrvList[SrvIndex].Type == Type) &&
1500             EFI_IP4_EQUAL (&Response->Dhcp4.Header.ServerAddr, &SrvList[SrvIndex].IpAddr)) {
1501           break;
1502         }
1503         SrvIndex++;
1504       }
1505
1506       if ((IpCount != SrvIndex) || (IpCount == 0)) {
1507         break;
1508       }
1509
1510       SrvIndex = 0;
1511       RepIndex++;
1512
1513       Response = (EFI_DHCP4_PACKET *) ((UINT8 *) Response + Response->Size);
1514     }
1515
1516     if (RepIndex < Token.ResponseCount) {
1517       //
1518       // Cache the right PXE reply packet here, set valid flag later.
1519       // Especially for PXE discover packet, store it into mode data here.
1520       //
1521       if (Private->IsDoDiscover) {
1522         PxeBcCacheDhcp4Packet (&Private->PxeReply.Dhcp4.Packet.Ack, Response);
1523         CopyMem (&Mode->PxeDiscover, &Token.Packet->Dhcp4, Token.Packet->Length);
1524       } else {
1525         PxeBcCacheDhcp4Packet (&Private->ProxyOffer.Dhcp4.Packet.Offer, Response);
1526       }
1527     } else {
1528       //
1529       // Not found the right PXE reply packet.
1530       //
1531       Status = EFI_NOT_FOUND;
1532     }
1533     if (Token.ResponseList != NULL) {
1534       FreePool (Token.ResponseList);
1535     }
1536   }
1537
1538   FreePool (Token.Packet);
1539   return Status;
1540 }
1541
1542 /**
1543   Switch the Ip4 policy to static.
1544
1545   @param[in]  Private             The pointer to PXEBC_PRIVATE_DATA.
1546
1547   @retval     EFI_SUCCESS         The policy is already configured to static.
1548   @retval     Others              Other error as indicated..
1549
1550 **/
1551 EFI_STATUS
1552 PxeBcSetIp4Policy (
1553   IN PXEBC_PRIVATE_DATA            *Private
1554   )
1555 {
1556   EFI_STATUS                   Status;
1557   EFI_IP4_CONFIG2_PROTOCOL     *Ip4Config2;
1558   EFI_IP4_CONFIG2_POLICY       Policy;
1559   UINTN                        DataSize;
1560
1561   Ip4Config2 = Private->Ip4Config2;
1562   DataSize = sizeof (EFI_IP4_CONFIG2_POLICY);
1563   Status = Ip4Config2->GetData (
1564                        Ip4Config2,
1565                        Ip4Config2DataTypePolicy,
1566                        &DataSize,
1567                        &Policy
1568                        );
1569   if (EFI_ERROR (Status)) {
1570     return Status;
1571   }
1572
1573   if (Policy != Ip4Config2PolicyStatic) {
1574     Policy = Ip4Config2PolicyStatic;
1575     Status= Ip4Config2->SetData (
1576                           Ip4Config2,
1577                           Ip4Config2DataTypePolicy,
1578                           sizeof (EFI_IP4_CONFIG2_POLICY),
1579                           &Policy
1580                           );
1581     if (EFI_ERROR (Status)) {
1582       return Status;
1583     }
1584   }
1585
1586   return  EFI_SUCCESS;
1587 }
1588
1589 /**
1590   Start the D.O.R.A DHCPv4 process to acquire the IPv4 address and other PXE boot information.
1591
1592   @param[in]  Private           Pointer to PxeBc private data.
1593   @param[in]  Dhcp4             Pointer to the EFI_DHCP4_PROTOCOL
1594
1595   @retval EFI_SUCCESS           The D.O.R.A process successfully finished.
1596   @retval Others                Failed to finish the D.O.R.A process.
1597
1598 **/
1599 EFI_STATUS
1600 PxeBcDhcp4Dora (
1601   IN PXEBC_PRIVATE_DATA        *Private,
1602   IN EFI_DHCP4_PROTOCOL        *Dhcp4
1603   )
1604 {
1605   EFI_PXE_BASE_CODE_MODE       *PxeMode;
1606   EFI_DHCP4_CONFIG_DATA        Config;
1607   EFI_DHCP4_MODE_DATA          Mode;
1608   EFI_DHCP4_PACKET_OPTION      *OptList[PXEBC_DHCP4_OPTION_MAX_NUM];
1609   UINT8                        Buffer[PXEBC_DHCP4_OPTION_MAX_SIZE];
1610   UINT32                       OptCount;
1611   EFI_STATUS                   Status;
1612
1613   ASSERT (Dhcp4 != NULL);
1614
1615   Status   = EFI_SUCCESS;
1616   PxeMode  = Private->PxeBc.Mode;
1617
1618   //
1619   // Build option list for the request packet.
1620   //
1621   OptCount = PxeBcBuildDhcp4Options (Private, OptList, Buffer, FALSE);
1622   ASSERT (OptCount> 0);
1623
1624   ZeroMem (&Mode, sizeof (EFI_DHCP4_MODE_DATA));
1625   ZeroMem (&Config, sizeof (EFI_DHCP4_CONFIG_DATA));
1626
1627   Config.OptionCount      = OptCount;
1628   Config.OptionList       = OptList;
1629   Config.Dhcp4Callback    = PxeBcDhcp4CallBack;
1630   Config.CallbackContext  = Private;
1631   Config.DiscoverTryCount = PXEBC_DHCP_RETRIES;
1632   Config.DiscoverTimeout  = mPxeDhcpTimeout;
1633
1634   //
1635   // Configure the DHCPv4 instance for PXE boot.
1636   //
1637   Status = Dhcp4->Configure (Dhcp4, &Config);
1638   if (EFI_ERROR (Status)) {
1639     goto ON_EXIT;
1640   }
1641
1642   //
1643   // Initialize the record fields for DHCPv4 offer in private data.
1644   //
1645   Private->IsProxyRecved = FALSE;
1646   Private->OfferNum      = 0;
1647   ZeroMem (Private->OfferCount, sizeof (Private->OfferCount));
1648   ZeroMem (Private->OfferIndex, sizeof (Private->OfferIndex));
1649
1650   //
1651   // Start DHCPv4 D.O.R.A. process to acquire IPv4 address. This may
1652   // have already been done, thus do not leave in error if the return
1653   // code is EFI_ALREADY_STARTED.
1654   //
1655   Status = Dhcp4->Start (Dhcp4, NULL);
1656   if (EFI_ERROR (Status) && Status != EFI_ALREADY_STARTED) {
1657     if (Status == EFI_ICMP_ERROR) {
1658       PxeMode->IcmpErrorReceived = TRUE;
1659     }
1660     goto ON_EXIT;
1661   }
1662
1663   //
1664   // Get the acquired IPv4 address and store them.
1665   //
1666   Status = Dhcp4->GetModeData (Dhcp4, &Mode);
1667   if (EFI_ERROR (Status)) {
1668     goto ON_EXIT;
1669   }
1670
1671   ASSERT (Mode.State == Dhcp4Bound);
1672
1673   CopyMem (&Private->StationIp, &Mode.ClientAddress, sizeof (EFI_IPv4_ADDRESS));
1674   CopyMem (&Private->SubnetMask, &Mode.SubnetMask, sizeof (EFI_IPv4_ADDRESS));
1675   CopyMem (&Private->GatewayIp, &Mode.RouterAddress, sizeof (EFI_IPv4_ADDRESS));
1676   CopyMem (&PxeMode->StationIp, &Private->StationIp, sizeof (EFI_IPv4_ADDRESS));
1677   CopyMem (&PxeMode->SubnetMask, &Private->SubnetMask, sizeof (EFI_IPv4_ADDRESS));
1678
1679   Status = PxeBcFlushStationIp (Private, &Private->StationIp, &Private->SubnetMask);
1680   if (EFI_ERROR (Status)) {
1681     goto ON_EXIT;
1682   }
1683
1684   //
1685   // Check the selected offer whether BINL retry is needed.
1686   //
1687   Status = PxeBcHandleDhcp4Offer (Private);
1688
1689   AsciiPrint ("\n  Station IP address is ");
1690
1691   PxeBcShowIp4Addr (&Private->StationIp.v4);
1692   AsciiPrint ("\n");
1693
1694 ON_EXIT:
1695   if (EFI_ERROR (Status)) {
1696     Dhcp4->Stop (Dhcp4);
1697     Dhcp4->Configure (Dhcp4, NULL);
1698   } else {
1699     ZeroMem (&Config, sizeof (EFI_DHCP4_CONFIG_DATA));
1700     Dhcp4->Configure (Dhcp4, &Config);
1701     Private->IsAddressOk = TRUE;
1702   }
1703
1704   return Status;
1705 }