MdeModulePkg/Universal/Network/Dhcp4Dxe/Dhcp4Option.c

   1 /** @file
   2   Function to validate, parse, process the DHCP options.
   3
   4 Copyright (c) 2006 - 2009, Intel Corporation.<BR>
   5 All rights reserved. This program and the accompanying materials
   6 are licensed and made available under the terms and conditions of the BSD License
   7 which accompanies this distribution.  The full text of the license may be found at
   8 http://opensource.org/licenses/bsd-license.php
   9
  10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "Dhcp4Impl.h"
  16
  17 ///
  18 /// A list of the format of DHCP Options sorted by option tag
  19 /// to validate a dhcp message. Refere the comments of the
  20 /// DHCP_OPTION_FORMAT structure.
  21 ///
  22 DHCP_OPTION_FORMAT DhcpOptionFormats[] = {
  23   {DHCP_TAG_NETMASK,        DHCP_OPTION_IP,     1, 1  , TRUE},
  24   {DHCP_TAG_TIME_OFFSET,    DHCP_OPTION_INT32,  1, 1  , FALSE},
  25   {DHCP_TAG_ROUTER,         DHCP_OPTION_IP,     1, -1 , TRUE},
  26   {DHCP_TAG_TIME_SERVER,    DHCP_OPTION_IP,     1, -1 , FALSE},
  27   {DHCP_TAG_NAME_SERVER,    DHCP_OPTION_IP,     1, -1 , FALSE},
  28   {DHCP_TAG_DNS_SERVER,     DHCP_OPTION_IP,     1, -1 , FALSE},
  29   {DHCP_TAG_LOG_SERVER,     DHCP_OPTION_IP,     1, -1 , FALSE},
  30   {DHCP_TAG_COOKIE_SERVER,  DHCP_OPTION_IP,     1, -1 , FALSE},
  31   {DHCP_TAG_LPR_SERVER,     DHCP_OPTION_IP,     1, -1 , FALSE},
  32   {DHCP_TAG_IMPRESS_SERVER, DHCP_OPTION_IP,     1, -1 , FALSE},
  33   {DHCP_TAG_RL_SERVER,      DHCP_OPTION_IP,     1, -1 , FALSE},
  34   {DHCP_TAG_HOSTNAME,       DHCP_OPTION_INT8,   1, -1 , FALSE},
  35   {DHCP_TAG_BOOTFILE_LEN,   DHCP_OPTION_INT16,  1, 1  , FALSE},
  36   {DHCP_TAG_DUMP,           DHCP_OPTION_INT8,   1, -1 , FALSE},
  37   {DHCP_TAG_DOMAINNAME,     DHCP_OPTION_INT8,   1, -1 , FALSE},
  38   {DHCP_TAG_SWAP_SERVER,    DHCP_OPTION_IP,     1, 1  , FALSE},
  39   {DHCP_TAG_ROOTPATH,       DHCP_OPTION_INT8,   1, -1 , FALSE},
  40   {DHCP_TAG_EXTEND_PATH,    DHCP_OPTION_INT8,   1, -1 , FALSE},
  41
  42   {DHCP_TAG_IPFORWARD,      DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  43   {DHCP_TAG_NONLOCAL_SRR,   DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  44   {DHCP_TAG_POLICY_SRR,     DHCP_OPTION_IPPAIR, 1, -1 , FALSE},
  45   {DHCP_TAG_EMTU,           DHCP_OPTION_INT16,  1, 1  , FALSE},
  46   {DHCP_TAG_TTL,            DHCP_OPTION_INT8,   1, 1  , FALSE},
  47   {DHCP_TAG_PATHMTU_AGE,    DHCP_OPTION_INT32,  1, 1  , FALSE},
  48   {DHCP_TAG_PATHMTU_PLATEAU,DHCP_OPTION_INT16,  1, -1 , FALSE},
  49
  50   {DHCP_TAG_IFMTU,          DHCP_OPTION_INT16,  1, 1  , FALSE},
  51   {DHCP_TAG_SUBNET_LOCAL,   DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  52   {DHCP_TAG_BROADCAST,      DHCP_OPTION_IP,     1, 1  , FALSE},
  53   {DHCP_TAG_DISCOVER_MASK,  DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  54   {DHCP_TAG_SUPPLY_MASK,    DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  55   {DHCP_TAG_DISCOVER_ROUTE, DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  56   {DHCP_TAG_ROUTER_SOLICIT, DHCP_OPTION_IP,     1, 1  , FALSE},
  57   {DHCP_TAG_STATIC_ROUTE,   DHCP_OPTION_IPPAIR, 1, -1 , FALSE},
  58
  59   {DHCP_TAG_TRAILER,        DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  60   {DHCP_TAG_ARPAGE,         DHCP_OPTION_INT32,  1, 1  , FALSE},
  61   {DHCP_TAG_ETHER_ENCAP,    DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  62
  63   {DHCP_TAG_TCP_TTL,        DHCP_OPTION_INT8,   1, 1  , FALSE},
  64   {DHCP_TAG_KEEP_INTERVAL,  DHCP_OPTION_INT32,  1, 1  , FALSE},
  65   {DHCP_TAG_KEEP_GARBAGE,   DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  66
  67   {DHCP_TAG_NIS_DOMAIN,     DHCP_OPTION_INT8,   1, -1 , FALSE},
  68   {DHCP_TAG_NIS_SERVER,     DHCP_OPTION_IP,     1, -1 , FALSE},
  69   {DHCP_TAG_NTP_SERVER,     DHCP_OPTION_IP,     1, -1 , FALSE},
  70   {DHCP_TAG_VENDOR,         DHCP_OPTION_INT8,   1, -1 , FALSE},
  71   {DHCP_TAG_NBNS,           DHCP_OPTION_IP,     1, -1 , FALSE},
  72   {DHCP_TAG_NBDD,           DHCP_OPTION_IP,     1, -1 , FALSE},
  73   {DHCP_TAG_NBTYPE,         DHCP_OPTION_INT8,   1, 1  , FALSE},
  74   {DHCP_TAG_NBSCOPE,        DHCP_OPTION_INT8,   1, -1 , FALSE},
  75   {DHCP_TAG_XFONT,          DHCP_OPTION_IP,     1, -1 , FALSE},
  76   {DHCP_TAG_XDM,            DHCP_OPTION_IP,     1, -1 , FALSE},
  77
  78   {DHCP_TAG_REQUEST_IP,     DHCP_OPTION_IP,     1, 1  , FALSE},
  79   {DHCP_TAG_LEASE,          DHCP_OPTION_INT32,  1, 1  , TRUE},
  80   {DHCP_TAG_OVERLOAD,       DHCP_OPTION_INT8,   1, 1  , TRUE},
  81   {DHCP_TAG_TYPE,           DHCP_OPTION_INT8,   1, 1  , TRUE},
  82   {DHCP_TAG_SERVER_ID,      DHCP_OPTION_IP,     1, 1  , TRUE},
  83   {DHCP_TAG_PARA_LIST,      DHCP_OPTION_INT8,   1, -1 , FALSE},
  84   {DHCP_TAG_MESSAGE,        DHCP_OPTION_INT8,   1, -1 , FALSE},
  85   {DHCP_TAG_MAXMSG,         DHCP_OPTION_INT16,  1, 1  , FALSE},
  86   {DHCP_TAG_T1,             DHCP_OPTION_INT32,  1, 1  , TRUE},
  87   {DHCP_TAG_T2,             DHCP_OPTION_INT32,  1, 1  , TRUE},
  88   {DHCP_TAG_VENDOR_CLASS,   DHCP_OPTION_INT8,   1, -1 , FALSE},
  89   {DHCP_TAG_CLIENT_ID,      DHCP_OPTION_INT8,   2, -1 , FALSE},
  90
  91   {DHCP_TAG_NISPLUS,        DHCP_OPTION_INT8,   1, -1 , FALSE},
  92   {DHCP_TAG_NISPLUS_SERVER, DHCP_OPTION_IP,     1, -1 , FALSE},
  93
  94   {DHCP_TAG_TFTP,           DHCP_OPTION_INT8,   1, -1 , FALSE},
  95   {DHCP_TAG_BOOTFILE,       DHCP_OPTION_INT8,   1, -1 , FALSE},
  96
  97   {DHCP_TAG_MOBILEIP,       DHCP_OPTION_IP,     0, -1 , FALSE},
  98   {DHCP_TAG_SMTP,           DHCP_OPTION_IP,     1, -1 , FALSE},
  99   {DHCP_TAG_POP3,           DHCP_OPTION_IP,     1, -1 , FALSE},
 100   {DHCP_TAG_NNTP,           DHCP_OPTION_IP,     1, -1 , FALSE},
 101   {DHCP_TAG_WWW,            DHCP_OPTION_IP,     1, -1 , FALSE},
 102   {DHCP_TAG_FINGER,         DHCP_OPTION_IP,     1, -1 , FALSE},
 103   {DHCP_TAG_IRC,            DHCP_OPTION_IP,     1, -1 , FALSE},
 104   {DHCP_TAG_STTALK,         DHCP_OPTION_IP,     1, -1 , FALSE},
 105   {DHCP_TAG_STDA,           DHCP_OPTION_IP,     1, -1 , FALSE},
 106
 107   {DHCP_TAG_CLASSLESS_ROUTE,DHCP_OPTION_INT8,   5, -1 , FALSE},
 108 };
 109
 110
 111 /**
 112   Binary search the DhcpOptionFormats array to find the format
 113   information about a specific option.
 114
 115   @param[in]  Tag                    The option's tag.
 116
 117   @return The point to the option's format, NULL if not found.
 118
 119 **/
 120 DHCP_OPTION_FORMAT *
 121 DhcpFindOptionFormat (
 122   IN UINT8                  Tag
 123   )
 124 {
 125   INTN                      Left;
 126   INTN                      Right;
 127   INTN                      Middle;
 128
 129   Left  = 0;
 130   Right = sizeof (DhcpOptionFormats) / sizeof (DHCP_OPTION_FORMAT) - 1;
 131
 132   while (Right >= Left) {
 133     Middle = (Left + Right) / 2;
 134
 135     if (Tag == DhcpOptionFormats[Middle].Tag) {
 136       return &DhcpOptionFormats[Middle];
 137     }
 138
 139     if (Tag < DhcpOptionFormats[Middle].Tag) {
 140       Right = Middle - 1;
 141     } else {
 142       Left  = Middle + 1;
 143     }
 144   }
 145
 146   return NULL;
 147 }
 148
 149
 150 /**
 151   Validate whether a single DHCP option is valid according to its format.
 152
 153   @param[in]  Format                 The option's format
 154   @param[in]  OptValue               The value of the option
 155   @param[in]  Len                    The length of the option value
 156
 157   @retval TRUE     The option is valid.
 158   @retval FALSE    Otherwise.
 159
 160 **/
 161 BOOLEAN
 162 DhcpOptionIsValid (
 163   IN DHCP_OPTION_FORMAT     *Format,
 164   IN UINT8                  *OptValue,
 165   IN INTN                   Len
 166   )
 167 {
 168   INTN                      Unit;
 169   INTN                      Occur;
 170   INTN                      Index;
 171
 172   Unit = 0;
 173
 174   switch (Format->Type) {
 175   case DHCP_OPTION_SWITCH:
 176   case DHCP_OPTION_INT8:
 177     Unit = 1;
 178     break;
 179
 180   case DHCP_OPTION_INT16:
 181     Unit = 2;
 182     break;
 183
 184   case DHCP_OPTION_INT32:
 185   case DHCP_OPTION_IP:
 186     Unit = 4;
 187     break;
 188
 189   case DHCP_OPTION_IPPAIR:
 190     Unit = 8;
 191     break;
 192   }
 193
 194   ASSERT (Unit != 0);
 195
 196   //
 197   // Validate that the option appears in the full units.
 198   //
 199   if ((Len % Unit) != 0) {
 200     return FALSE;
 201   }
 202
 203   //
 204   // Validate the occurance of the option unit is with in [MinOccur, MaxOccur]
 205   //
 206   Occur = Len / Unit;
 207
 208   if (((Format->MinOccur != -1) && (Occur < Format->MinOccur)) ||
 209       ((Format->MaxOccur != -1) && (Occur > Format->MaxOccur))
 210       ) {
 211     return FALSE;
 212   }
 213
 214   //
 215   // If the option is of type switch, only 0/1 are valid values.
 216   //
 217   if (Format->Type == DHCP_OPTION_SWITCH) {
 218     for (Index = 0; Index < Occur; Index++) {
 219       if ((OptValue[Index] != 0) && (OptValue[Index] != 1)) {
 220         return FALSE;
 221       }
 222     }
 223   }
 224
 225   return TRUE;
 226 }
 227
 228
 229 /**
 230   Extract the client interested options, all the parameters are
 231   converted to host byte order.
 232
 233   @param[in]  Tag                    The DHCP option tag
 234   @param[in]  Len                    The length of the option
 235   @param[in]  Data                   The value of the DHCP option
 236   @param[out] Para                   The variable to save the interested parameter
 237
 238   @retval EFI_SUCCESS            The DHCP option is successfully extracted.
 239   @retval EFI_INVALID_PARAMETER  The DHCP option is mal-formated
 240
 241 **/
 242 EFI_STATUS
 243 DhcpGetParameter (
 244   IN  UINT8                  Tag,
 245   IN  INTN                   Len,
 246   IN  UINT8                  *Data,
 247   OUT DHCP_PARAMETER         *Para
 248   )
 249 {
 250   switch (Tag) {
 251   case DHCP_TAG_NETMASK:
 252     Para->NetMask = NetGetUint32 (Data);
 253     break;
 254
 255   case DHCP_TAG_ROUTER:
 256     //
 257     // Return the first router to consumer which is the preferred one
 258     //
 259     Para->Router = NetGetUint32 (Data);
 260     break;
 261
 262   case DHCP_TAG_LEASE:
 263     Para->Lease = NetGetUint32 (Data);
 264     break;
 265
 266   case DHCP_TAG_OVERLOAD:
 267     Para->Overload = *Data;
 268
 269     if ((Para->Overload < 1) || (Para->Overload > 3)) {
 270       return EFI_INVALID_PARAMETER;
 271     }
 272     break;
 273
 274   case DHCP_TAG_TYPE:
 275     Para->DhcpType = *Data;
 276
 277     if ((Para->DhcpType < 1) || (Para->DhcpType > 9)) {
 278       return EFI_INVALID_PARAMETER;
 279     }
 280     break;
 281
 282   case DHCP_TAG_SERVER_ID:
 283     Para->ServerId = NetGetUint32 (Data);
 284     break;
 285
 286   case DHCP_TAG_T1:
 287     Para->T1 = NetGetUint32 (Data);
 288     break;
 289
 290   case DHCP_TAG_T2:
 291     Para->T2 = NetGetUint32 (Data);
 292     break;
 293   }
 294
 295   return EFI_SUCCESS;
 296 }
 297
 298
 299 /**
 300   Inspect all the options in a single buffer. DHCP options may be contained
 301   in several buffers, such as the BOOTP options filed, boot file or server
 302   name. Each option buffer is required to end with DHCP_TAG_EOP.
 303
 304   @param[in]  Buffer                 The buffer which contains DHCP options
 305   @param[in]  BufLen                 The length of the buffer
 306   @param[in]  Check                  The callback function for each option found
 307   @param[in]  Context                The opaque parameter for the Check
 308   @param[out] Overload               Variable to save the value of DHCP_TAG_OVERLOAD
 309                                      option.
 310
 311   @retval EFI_SUCCESS            All the options are valid
 312   @retval EFI_INVALID_PARAMETER  The options are mal-formated.
 313
 314 **/
 315 EFI_STATUS
 316 DhcpIterateBufferOptions (
 317   IN  UINT8                 *Buffer,
 318   IN  INTN                  BufLen,
 319   IN  DHCP_CHECK_OPTION     Check             OPTIONAL,
 320   IN  VOID                  *Context,
 321   OUT UINT8                 *Overload         OPTIONAL
 322   )
 323 {
 324   INTN                      Cur;
 325   UINT8                     Tag;
 326   UINT8                     Len;
 327
 328   Cur = 0;
 329
 330   while (Cur < BufLen) {
 331     Tag = Buffer[Cur];
 332
 333     if (Tag == DHCP_TAG_PAD) {
 334       Cur++;
 335       continue;
 336     } else if (Tag == DHCP_TAG_EOP) {
 337       return EFI_SUCCESS;
 338     }
 339
 340     Cur++;
 341
 342     if (Cur == BufLen) {
 343       return EFI_INVALID_PARAMETER;
 344     }
 345
 346     Len = Buffer[Cur++];
 347
 348     if (Cur + Len > BufLen) {
 349       return EFI_INVALID_PARAMETER;
 350     }
 351
 352     if ((Tag == DHCP_TAG_OVERLOAD) && (Overload != NULL)) {
 353       if (Len != 1) {
 354         return EFI_INVALID_PARAMETER;
 355       }
 356
 357       *Overload = Buffer[Cur];
 358     }
 359
 360     if ((Check != NULL) && EFI_ERROR (Check (Tag, Len, Buffer + Cur, Context))) {
 361       return EFI_INVALID_PARAMETER;
 362     }
 363
 364     Cur += Len;
 365   }
 366
 367   //
 368   // Each option buffer is expected to end with an EOP
 369   //
 370   return EFI_INVALID_PARAMETER;
 371 }
 372
 373
 374 /**
 375   Iterate through a DHCP message to visit each option. First inspect
 376   all the options in the OPTION field. Then if overloaded, inspect
 377   the options in FILENAME and SERVERNAME fields. One option may be
 378   encoded in several places. See RFC 3396 Encoding Long Options in DHCP
 379
 380   @param[in]  Packet                 The DHCP packet to check the options for
 381   @param[in]  Check                  The callback function to be called for each option
 382                                      found
 383   @param[in]  Context                The opaque parameter for Check
 384
 385   @retval EFI_SUCCESS            The DHCP packet's options are well formated
 386   @retval EFI_INVALID_PARAMETER  The DHCP packet's options are not well formated
 387
 388 **/
 389 EFI_STATUS
 390 DhcpIterateOptions (
 391   IN  EFI_DHCP4_PACKET      *Packet,
 392   IN  DHCP_CHECK_OPTION     Check         OPTIONAL,
 393   IN  VOID                  *Context
 394   )
 395 {
 396   EFI_STATUS                Status;
 397   UINT8                     Overload;
 398
 399   Overload = 0;
 400
 401   Status   = DhcpIterateBufferOptions (
 402                Packet->Dhcp4.Option,
 403                Packet->Length - sizeof (EFI_DHCP4_HEADER) - sizeof (UINT32),
 404                Check,
 405                Context,
 406                &Overload
 407                );
 408
 409   if (EFI_ERROR (Status)) {
 410     return Status;
 411   }
 412
 413   if ((Overload == DHCP_OVERLOAD_FILENAME) || (Overload == DHCP_OVERLOAD_BOTH)) {
 414     Status = DhcpIterateBufferOptions (
 415                (UINT8 *) Packet->Dhcp4.Header.BootFileName,
 416                128,
 417                Check,
 418                Context,
 419                NULL
 420                );
 421
 422     if (EFI_ERROR (Status)) {
 423       return Status;
 424     }
 425   }
 426
 427   if ((Overload == DHCP_OVERLOAD_SVRNAME) || (Overload == DHCP_OVERLOAD_BOTH)) {
 428     Status = DhcpIterateBufferOptions (
 429                (UINT8 *) Packet->Dhcp4.Header.ServerName,
 430                64,
 431                Check,
 432                Context,
 433                NULL
 434                );
 435
 436     if (EFI_ERROR (Status)) {
 437       return Status;
 438     }
 439   }
 440
 441   return EFI_SUCCESS;
 442 }
 443
 444
 445 /**
 446   Call back function to DhcpIterateOptions to compute each option's
 447   length. It just adds the data length of all the occurances of this
 448   Tag. Context is an array of 256 DHCP_OPTION_COUNT.
 449
 450   @param[in]  Tag                    The current option to check
 451   @param[in]  Len                    The length of the option data
 452   @param[in]  Data                   The option data
 453   @param[in]  Context                The context, which is a array of 256
 454                                      DHCP_OPTION_COUNT.
 455
 456   @retval EFI_SUCCESS            It always returns EFI_SUCCESS.
 457
 458 **/
 459 EFI_STATUS
 460 DhcpGetOptionLen (
 461   IN UINT8                  Tag,
 462   IN UINT8                  Len,
 463   IN UINT8                  *Data,
 464   IN VOID                   *Context
 465   )
 466 {
 467   DHCP_OPTION_COUNT         *OpCount;
 468
 469   OpCount             = (DHCP_OPTION_COUNT *) Context;
 470   OpCount[Tag].Offset = (UINT16) (OpCount[Tag].Offset + Len);
 471
 472   return EFI_SUCCESS;
 473 }
 474
 475
 476 /**
 477   Call back function to DhcpIterateOptions to consolidate each option's
 478   data. There are maybe several occurrence of the same option.
 479
 480   @param[in]  Tag                    The option to consolidate its data
 481   @param[in]  Len                    The length of option data
 482   @param[in]  Data                   The data of the option's current occurance
 483   @param[in]  Context                The context, which is DHCP_OPTION_CONTEXT. This
 484                                      array is  just a wrap to pass THREE parameters.
 485
 486   @retval EFI_SUCCESS            It always returns EFI_SUCCESS
 487
 488 **/
 489 EFI_STATUS
 490 DhcpFillOption (
 491   IN UINT8                  Tag,
 492   IN UINT8                  Len,
 493   IN UINT8                  *Data,
 494   IN VOID                   *Context
 495   )
 496 {
 497   DHCP_OPTION_CONTEXT       *OptContext;
 498   DHCP_OPTION_COUNT         *OptCount;
 499   DHCP_OPTION               *Options;
 500   UINT8                     *Buf;
 501   UINT8                     Index;
 502
 503   OptContext  = (DHCP_OPTION_CONTEXT *) Context;
 504
 505   OptCount    = OptContext->OpCount;
 506   Index       = OptCount[Tag].Index;
 507   Options     = OptContext->Options;
 508   Buf         = OptContext->Buf;
 509
 510   if (Options[Index].Data == NULL) {
 511     Options[Index].Tag  = Tag;
 512     Options[Index].Data = Buf + OptCount[Tag].Offset;
 513   }
 514
 515   CopyMem (Buf + OptCount[Tag].Offset, Data, Len);
 516
 517   OptCount[Tag].Offset  = (UINT16) (OptCount[Tag].Offset + Len);
 518   Options[Index].Len    = (UINT16) (Options[Index].Len + Len);
 519   return EFI_SUCCESS;
 520 }
 521
 522
 523 /**
 524   Parse the options of a DHCP packet. It supports RFC 3396: Encoding
 525   Long Options in DHCP. That is, it will combine all the option value
 526   of all the occurances of each option.
 527   A little bit of implemenation:
 528   It adopts the "Key indexed counting" algorithm. First, it allocates
 529   an array of 256 DHCP_OPTION_COUNTs because DHCP option tag is encoded
 530   as a UINT8. It then iterates the DHCP packet to get data length of
 531   each option by calling DhcpIterOptions with DhcpGetOptionLen. Now, it
 532   knows the number of present options and their length. It allocates a
 533   array of DHCP_OPTION and a continuous buffer after the array to put
 534   all the options' data. Each option's data is pointed to by the Data
 535   field in DHCP_OPTION structure. At last, it call DhcpIterateOptions
 536   with DhcpFillOption to fill each option's data to its position in the
 537   buffer.
 538
 539   @param[in]  Packet                 The DHCP packet to parse the options
 540   @param[out] Count                  The number of valid dhcp options present in the
 541                                      packet
 542   @param[out] OptionPoint            The array that contains the DHCP options. Caller
 543                                      should free it.
 544
 545   @retval EFI_OUT_OF_RESOURCES   Failed to allocate memory to parse the packet.
 546   @retval EFI_INVALID_PARAMETER  The options are mal-formated
 547   @retval EFI_SUCCESS            The options are parsed into OptionPoint
 548
 549 **/
 550 EFI_STATUS
 551 DhcpParseOption (
 552   IN  EFI_DHCP4_PACKET      *Packet,
 553   OUT INTN                  *Count,
 554   OUT DHCP_OPTION           **OptionPoint
 555   )
 556 {
 557   DHCP_OPTION_CONTEXT       Context;
 558   DHCP_OPTION               *Options;
 559   DHCP_OPTION_COUNT         *OptCount;
 560   EFI_STATUS                Status;
 561   UINT16                    TotalLen;
 562   INTN                      OptNum;
 563   INTN                      Index;
 564
 565   ASSERT ((Count != NULL) && (OptionPoint != NULL));
 566
 567   //
 568   // First compute how many options and how long each option is
 569   // with the "Key indexed counting" algorithms.
 570   //
 571   OptCount = AllocateZeroPool (DHCP_MAX_OPTIONS * sizeof (DHCP_OPTION_COUNT));
 572
 573   if (OptCount == NULL) {
 574     return EFI_OUT_OF_RESOURCES;
 575   }
 576
 577   Status = DhcpIterateOptions (Packet, DhcpGetOptionLen, OptCount);
 578
 579   if (EFI_ERROR (Status)) {
 580     goto ON_EXIT;
 581   }
 582
 583   //
 584   // Before the loop, Offset is the length of the option. After loop,
 585   // OptCount[Index].Offset specifies the offset into the continuous
 586   // option value buffer to put the data.
 587   //
 588   TotalLen  = 0;
 589   OptNum    = 0;
 590
 591   for (Index = 0; Index < DHCP_MAX_OPTIONS; Index++) {
 592     if (OptCount[Index].Offset != 0) {
 593       OptCount[Index].Index   = (UINT8) OptNum;
 594
 595       TotalLen                = (UINT16) (TotalLen + OptCount[Index].Offset);
 596       OptCount[Index].Offset  = (UINT16) (TotalLen - OptCount[Index].Offset);
 597
 598       OptNum++;
 599     }
 600   }
 601
 602   *Count        = OptNum;
 603   *OptionPoint  = NULL;
 604
 605   if (OptNum == 0) {
 606     goto ON_EXIT;
 607   }
 608
 609   //
 610   // Allocate a buffer to hold the DHCP options, and after that, a
 611   // continuous buffer to put all the options' data.
 612   //
 613   Options = AllocateZeroPool (OptNum * sizeof (DHCP_OPTION) + TotalLen);
 614
 615   if (Options == NULL) {
 616     Status = EFI_OUT_OF_RESOURCES;
 617     goto ON_EXIT;
 618   }
 619
 620   Context.OpCount = OptCount;
 621   Context.Options = Options;
 622   Context.Buf     = (UINT8 *) (Options + OptNum);
 623
 624   Status          = DhcpIterateOptions (Packet, DhcpFillOption, &Context);
 625
 626   if (EFI_ERROR (Status)) {
 627     gBS->FreePool (Options);
 628     goto ON_EXIT;
 629   }
 630
 631   *OptionPoint = Options;
 632
 633 ON_EXIT:
 634   gBS->FreePool (OptCount);
 635   return Status;
 636 }
 637
 638
 639 /**
 640   Validate the packet's options. If necessary, allocate
 641   and fill in the interested parameters.
 642
 643   @param[in]  Packet                 The packet to validate the options
 644   @param[out] Para                   The variable to save the DHCP parameters.
 645
 646   @retval EFI_OUT_OF_RESOURCES   Failed to allocate memory to validate the packet.
 647   @retval EFI_INVALID_PARAMETER  The options are mal-formated
 648   @retval EFI_SUCCESS            The options are parsed into OptionPoint
 649
 650 **/
 651 EFI_STATUS
 652 DhcpValidateOptions (
 653   IN  EFI_DHCP4_PACKET      *Packet,
 654   OUT DHCP_PARAMETER        **Para       OPTIONAL
 655   )
 656 {
 657   DHCP_PARAMETER            Parameter;
 658   DHCP_OPTION_FORMAT        *Format;
 659   DHCP_OPTION               *AllOption;
 660   DHCP_OPTION               *Option;
 661   EFI_STATUS                Status;
 662   BOOLEAN                   Updated;
 663   INTN                      Count;
 664   INTN                      Index;
 665
 666   if (Para != NULL) {
 667     *Para = NULL;
 668   }
 669
 670   AllOption = NULL;
 671
 672   Status = DhcpParseOption (Packet, &Count, &AllOption);
 673   if (EFI_ERROR (Status) || (Count == 0)) {
 674     return Status;
 675   }
 676
 677   Updated = FALSE;
 678   ZeroMem (&Parameter, sizeof (Parameter));
 679
 680   for (Index = 0; Index < Count; Index++) {
 681     Option = &AllOption[Index];
 682     ASSERT (Option != NULL);
 683
 684     //
 685     // Find the format of the option then validate it.
 686     //
 687     Format = DhcpFindOptionFormat (Option->Tag);
 688
 689     if (Format == NULL) {
 690       continue;
 691     }
 692
 693     if (!DhcpOptionIsValid (Format, Option->Data, Option->Len)) {
 694       Status = EFI_INVALID_PARAMETER;
 695       goto ON_EXIT;
 696     }
 697
 698     //
 699     // Get the client interested parameters
 700     //
 701     if (Format->Alert && (Para != NULL)) {
 702       Updated = TRUE;
 703       Status  = DhcpGetParameter (Option->Tag, Option->Len, Option->Data, &Parameter);
 704
 705       if (EFI_ERROR (Status)) {
 706         goto ON_EXIT;
 707       }
 708     }
 709   }
 710
 711   if (Updated && (Para != NULL)) {
 712     if ((*Para = AllocatePool (sizeof (DHCP_PARAMETER))) == NULL) {
 713       Status = EFI_OUT_OF_RESOURCES;
 714       goto ON_EXIT;
 715     }
 716
 717     CopyMem (*Para, &Parameter, sizeof (**Para));
 718   }
 719
 720 ON_EXIT:
 721   gBS->FreePool (AllOption);
 722   return Status;
 723 }
 724
 725
 726
 727 /**
 728   Append an option to the memory, if the option is longer than
 729   255 bytes, splits it into several options.
 730
 731   @param[out] Buf                    The buffer to append the option to
 732   @param[in]  Tag                    The option's tag
 733   @param[in]  DataLen                The length of the option's data
 734   @param[in]  Data                   The option's data
 735
 736   @return The position to append the next option
 737
 738 **/
 739 UINT8 *
 740 DhcpAppendOption (
 741   OUT UINT8                  *Buf,
 742   IN  UINT8                  Tag,
 743   IN  UINT16                 DataLen,
 744   IN  UINT8                  *Data
 745   )
 746 {
 747   INTN                      Index;
 748   INTN                      Len;
 749
 750   ASSERT (DataLen != 0);
 751
 752   for (Index = 0; Index < (DataLen + 254) / 255; Index++) {
 753     Len      = MIN (255, DataLen - Index * 255);
 754
 755     *(Buf++) = Tag;
 756     *(Buf++) = (UINT8) Len;
 757     CopyMem (Buf, Data + Index * 255, Len);
 758
 759     Buf     += Len;
 760   }
 761
 762   return Buf;
 763 }
 764
 765
 766 /**
 767   Build a new DHCP packet from a seed packet. Options may be deleted or
 768   appended. The caller should free the NewPacket when finished using it.
 769
 770   @param[in]  SeedPacket             The seed packet to start with
 771   @param[in]  DeleteCount            The number of options to delete
 772   @param[in]  DeleteList             The options to delete from the packet
 773   @param[in]  AppendCount            The number of options to append
 774   @param[in]  AppendList             The options to append to the packet
 775   @param[out] NewPacket              The new packet, allocated and built by this
 776                                      function.
 777
 778   @retval EFI_OUT_OF_RESOURCES   Failed to allocate memory
 779   @retval EFI_INVALID_PARAMETER  The options in SeekPacket are mal-formated
 780   @retval EFI_SUCCESS            The packet is build.
 781
 782 **/
 783 EFI_STATUS
 784 DhcpBuild (
 785   IN  EFI_DHCP4_PACKET        *SeedPacket,
 786   IN  UINT32                  DeleteCount,
 787   IN  UINT8                   *DeleteList     OPTIONAL,
 788   IN  UINT32                  AppendCount,
 789   IN  EFI_DHCP4_PACKET_OPTION *AppendList[]   OPTIONAL,
 790   OUT EFI_DHCP4_PACKET        **NewPacket
 791   )
 792 {
 793   DHCP_OPTION               *Mark;
 794   DHCP_OPTION               *SeedOptions;
 795   EFI_DHCP4_PACKET          *Packet;
 796   EFI_STATUS                Status;
 797   INTN                      Count;
 798   UINT32                    Index;
 799   UINT32                    Len;
 800   UINT8                     *Buf;
 801
 802   //
 803   // Use an array of DHCP_OPTION to mark the existance
 804   // and position of each valid options.
 805   //
 806   Mark = AllocatePool (sizeof (DHCP_OPTION) * DHCP_MAX_OPTIONS);
 807
 808   if (Mark == NULL) {
 809     return EFI_OUT_OF_RESOURCES;
 810   }
 811
 812   for (Index = 0; Index < DHCP_MAX_OPTIONS; Index++) {
 813     Mark[Index].Tag = (UINT8) Index;
 814     Mark[Index].Len = 0;
 815   }
 816
 817   //
 818   // Get list of the options from the seed packet, then put
 819   // them to the mark array according to their tags.
 820   //
 821   SeedOptions = NULL;
 822   Status      = DhcpParseOption (SeedPacket, &Count, &SeedOptions);
 823
 824   if (EFI_ERROR (Status)) {
 825     goto ON_ERROR;
 826   }
 827
 828   for (Index = 0; Index < (UINT32) Count; Index++) {
 829     Mark[SeedOptions[Index].Tag] = SeedOptions[Index];
 830   }
 831
 832   //
 833   // Mark the option's length is zero if it is in the DeleteList.
 834   //
 835   for (Index = 0; Index < DeleteCount; Index++) {
 836     Mark[DeleteList[Index]].Len = 0;
 837   }
 838
 839   //
 840   // Add or replace the option if it is in the append list.
 841   //
 842   for (Index = 0; Index < AppendCount; Index++) {
 843     Mark[AppendList[Index]->OpCode].Len  = AppendList[Index]->Length;
 844     Mark[AppendList[Index]->OpCode].Data = AppendList[Index]->Data;
 845   }
 846
 847   //
 848   // compute the new packet length. No need to add 1 byte for
 849   // EOP option since EFI_DHCP4_PACKET includes one extra byte
 850   // for option. It is necessary to split the option if it is
 851   // longer than 255 bytes.
 852   //
 853   Len = sizeof (EFI_DHCP4_PACKET);
 854
 855   for (Index = 0; Index < DHCP_MAX_OPTIONS; Index++) {
 856     if (Mark[Index].Len != 0) {
 857       Len += ((Mark[Index].Len + 254) / 255) * 2 + Mark[Index].Len;
 858     }
 859   }
 860
 861   Status  = EFI_OUT_OF_RESOURCES;
 862   Packet  = (EFI_DHCP4_PACKET *) AllocatePool (Len);
 863
 864   if (Packet == NULL) {
 865     goto ON_ERROR;
 866   }
 867
 868   Packet->Size         = Len;
 869   Packet->Length       = 0;
 870   CopyMem (&Packet->Dhcp4.Header, &SeedPacket->Dhcp4.Header, sizeof (Packet->Dhcp4.Header));
 871   Packet->Dhcp4.Magik  = DHCP_OPTION_MAGIC;
 872   Buf                  = Packet->Dhcp4.Option;
 873
 874   for (Index = 0; Index < DHCP_MAX_OPTIONS; Index++) {
 875     if (Mark[Index].Len != 0) {
 876       Buf = DhcpAppendOption (Buf, Mark[Index].Tag, Mark[Index].Len, Mark[Index].Data);
 877     }
 878   }
 879
 880   *(Buf++)        = DHCP_TAG_EOP;
 881   Packet->Length  = sizeof (EFI_DHCP4_HEADER) + sizeof (UINT32)
 882                       + (UINT32) (Buf - Packet->Dhcp4.Option);
 883
 884   *NewPacket      = Packet;
 885   Status          = EFI_SUCCESS;
 886
 887 ON_ERROR:
 888   if (SeedOptions != NULL) {
 889     gBS->FreePool (SeedOptions);
 890   }
 891
 892   gBS->FreePool (Mark);
 893   return Status;
 894 }