dhcp4option.c

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/*++

Copyright (c) 2006, Intel Corporation                                                         
All rights reserved. This program and the accompanying materials                          
are licensed and made available under the terms and conditions of the BSD License         
which accompanies this distribution.  The full text of the license may be found at        
http://opensource.org/licenses/bsd-license.php                                            
                                                                                          
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 

Module Name:

  Dhcp4Option.c

Abstract:

  Function to validate, parse, process the DHCP options
  
--*/

#include "Dhcp4Impl.h"

//
// A list of the format of DHCP Options sorted by option tag
// to validate a dhcp message. Refere the comments of the
// DHCP_OPTION_FORMAT structure.
//
STATIC
DHCP_OPTION_FORMAT 
DhcpOptionFormats [] = {
  {DHCP_TAG_NETMASK,        DHCP_OPTION_IP,     1, 1  , TRUE},
  {DHCP_TAG_TIME_OFFSET,    DHCP_OPTION_INT32,  1, 1  , FALSE},
  {DHCP_TAG_ROUTER,         DHCP_OPTION_IP,     1, -1 , TRUE},
  {DHCP_TAG_TIME_SERVER,    DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_NAME_SERVER,    DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_DNS_SERVER,     DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_LOG_SERVER,     DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_COOKIE_SERVER,  DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_LPR_SERVER,     DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_IMPRESS_SERVER, DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_RL_SERVER,      DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_HOSTNAME,       DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_BOOTFILE_LEN,   DHCP_OPTION_INT16,  1, 1  , FALSE},
  {DHCP_TAG_DUMP,           DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_DOMAINNAME,     DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_SWAP_SERVER,    DHCP_OPTION_IP,     1, 1  , FALSE},
  {DHCP_TAG_ROOTPATH,       DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_EXTEND_PATH,    DHCP_OPTION_INT8,   1, -1 , FALSE},
  
  {DHCP_TAG_IPFORWARD,      DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  {DHCP_TAG_NONLOCAL_SRR,   DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  {DHCP_TAG_POLICY_SRR,     DHCP_OPTION_IPPAIR, 1, -1 , FALSE},
  {DHCP_TAG_EMTU,           DHCP_OPTION_INT16,  1, 1  , FALSE},
  {DHCP_TAG_TTL,            DHCP_OPTION_INT8,   1, 1  , FALSE},
  {DHCP_TAG_PATHMTU_AGE,    DHCP_OPTION_INT32,  1, 1  , FALSE},
  {DHCP_TAG_PATHMTU_PLATEAU,DHCP_OPTION_INT16,  1, -1 , FALSE},
  
  {DHCP_TAG_IFMTU,          DHCP_OPTION_INT16,  1, 1  , FALSE},
  {DHCP_TAG_SUBNET_LOCAL,   DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  {DHCP_TAG_BROADCAST,      DHCP_OPTION_IP,     1, 1  , FALSE},
  {DHCP_TAG_DISCOVER_MASK,  DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  {DHCP_TAG_SUPPLY_MASK,    DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  {DHCP_TAG_DISCOVER_ROUTE, DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  {DHCP_TAG_ROUTER_SOLICIT, DHCP_OPTION_IP,     1, 1  , FALSE},
  {DHCP_TAG_STATIC_ROUTE,   DHCP_OPTION_IPPAIR, 1, -1 , FALSE},

  {DHCP_TAG_TRAILER,        DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  {DHCP_TAG_ARPAGE,         DHCP_OPTION_INT32,  1, 1  , FALSE},
  {DHCP_TAG_ETHER_ENCAP,    DHCP_OPTION_SWITCH, 1, 1  , FALSE},
  
  {DHCP_TAG_TCP_TTL,        DHCP_OPTION_INT8,   1, 1  , FALSE},
  {DHCP_TAG_KEEP_INTERVAL,  DHCP_OPTION_INT32,  1, 1  , FALSE},
  {DHCP_TAG_KEEP_GARBAGE,   DHCP_OPTION_SWITCH, 1, 1  , FALSE},

  {DHCP_TAG_NIS_DOMAIN,     DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_NIS_SERVER,     DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_NTP_SERVER,     DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_VENDOR,         DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_NBNS,           DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_NBDD,           DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_NBTYPE,         DHCP_OPTION_INT8,   1, 1  , FALSE},
  {DHCP_TAG_NBSCOPE,        DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_XFONT,          DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_XDM,            DHCP_OPTION_IP,     1, -1 , FALSE},

  {DHCP_TAG_REQUEST_IP,     DHCP_OPTION_IP,     1, 1  , FALSE},
  {DHCP_TAG_LEASE,          DHCP_OPTION_INT32,  1, 1  , TRUE},
  {DHCP_TAG_OVERLOAD,       DHCP_OPTION_INT8,   1, 1  , TRUE},
  {DHCP_TAG_TYPE,           DHCP_OPTION_INT8,   1, 1  , TRUE},
  {DHCP_TAG_SERVER_ID,      DHCP_OPTION_IP,     1, 1  , TRUE},
  {DHCP_TAG_PARA_LIST,      DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_MESSAGE,        DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_MAXMSG,         DHCP_OPTION_INT16,  1, 1  , FALSE},
  {DHCP_TAG_T1,             DHCP_OPTION_INT32,  1, 1  , TRUE},
  {DHCP_TAG_T2,             DHCP_OPTION_INT32,  1, 1  , TRUE},
  {DHCP_TAG_VENDOR_CLASS,   DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_CLIENT_ID,      DHCP_OPTION_INT8,   2, -1 , FALSE},

  {DHCP_TAG_NISPLUS,        DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_NISPLUS_SERVER, DHCP_OPTION_IP,     1, -1 , FALSE},

  {DHCP_TAG_TFTP,           DHCP_OPTION_INT8,   1, -1 , FALSE},
  {DHCP_TAG_BOOTFILE,       DHCP_OPTION_INT8,   1, -1 , FALSE},

  {DHCP_TAG_MOBILEIP,       DHCP_OPTION_IP,     0, -1 , FALSE},
  {DHCP_TAG_SMTP,           DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_POP3,           DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_NNTP,           DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_WWW,            DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_FINGER,         DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_IRC,            DHCP_OPTION_IP,     1, -1 , FALSE},
  {DHCP_TAG_STTALK,         DHCP_OPTION_IP,     1, -1 , FALSE}, 
  {DHCP_TAG_STDA,           DHCP_OPTION_IP,     1, -1 , FALSE},
  
  {DHCP_TAG_CLASSLESS_ROUTE,DHCP_OPTION_INT8,   5, -1 , FALSE},
};

STATIC
DHCP_OPTION_FORMAT *
DhcpFindOptionFormat (
  IN UINT8                  Tag
  )
/*++

Routine Description:

  Binary search the DhcpOptionFormats array to find the format 
  information about a specific option.

Arguments:

  Tag - The option's tag.

Returns:

  The point to the option's format, NULL if not found.

--*/
{
  INTN                      Left;
  INTN                      Right;
  INTN                      Middle;

  Left  = 0;
  Right = sizeof (DhcpOptionFormats) / sizeof (DHCP_OPTION_FORMAT) - 1;

  while (Right >= Left) {
    Middle = (Left + Right) / 2;
    
    if (Tag == DhcpOptionFormats[Middle].Tag) {
      return &DhcpOptionFormats[Middle];
    }

    if (Tag < DhcpOptionFormats[Middle].Tag) {
      Right = Middle - 1;
    } else {
      Left = Middle + 1;
    }
  }

  return NULL;
}

STATIC
BOOLEAN
DhcpOptionIsValid (
  IN DHCP_OPTION_FORMAT     *Format,
  IN UINT8                  *OptValue,
  IN INTN                   Len
  )
/*++

Routine Description:

  Validate whether a single DHCP option is valid according to its format.

Arguments:

  Format    - The option's format
  OptValue  - The value of the option
  Len       - The length of the option value

Returns:

  TRUE is the option is valid, otherwise FALSE.

--*/
{
  INTN                      Unit;
  INTN                      Occur;
  INTN                      Index;

  Unit = 0;

  switch (Format->Type) {
  case DHCP_OPTION_SWITCH:
  case DHCP_OPTION_INT8:
    Unit = 1;
    break;

  case DHCP_OPTION_INT16:
    Unit = 2;
    break;

  case DHCP_OPTION_INT32:
  case DHCP_OPTION_IP:
    Unit = 4;
    break;

  case DHCP_OPTION_IPPAIR:
    Unit = 8;
    break;
  }

  ASSERT (Unit != 0);

  //
  // Validate that the option appears in the full units.
  //
  if ((Len % Unit) != 0) {
    return FALSE;
  }
  
  //
  // Validate the occurance of the option unit is with in [MinOccur, MaxOccur]
  //
  Occur = Len / Unit;

  if (((Format->MinOccur != -1) && (Occur < Format->MinOccur)) ||
      ((Format->MaxOccur != -1) && (Occur > Format->MaxOccur))) {
    return FALSE;
  }
  
  //
  // If the option is of type switch, only 0/1 are valid values.
  //
  if (Format->Type == DHCP_OPTION_SWITCH) {
    for (Index = 0; Index < Occur; Index++) {
      if ((OptValue[Index] != 0) && (OptValue[Index] != 1)) {
        return FALSE;
      }
    }
  }

  return TRUE;
}

STATIC
EFI_STATUS
DhcpGetParameter (
  IN UINT8                  Tag,
  IN INTN                   Len,
  IN UINT8                  *Data,
  IN DHCP_PARAMETER         *Para
  )
/*++

Routine Description:

  Extract the client interested options, all the parameters are
  converted to host byte order.

Arguments:

  Tag   - The DHCP option tag
  Len   - The length of the option
  Data  - The value of the DHCP option
  Para  - The variable to save the interested parameter

Returns:

  EFI_SUCCESS           - The DHCP option is successfully extracted.
  EFI_INVALID_PARAMETER - The DHCP option is mal-formated

--*/
{
  switch (Tag) {
  case DHCP_TAG_NETMASK:
    Para->NetMask = NetGetUint32 (Data);
    break;

  case DHCP_TAG_ROUTER:
    //
    // Return the first router to consumer which is the preferred one
    //
    Para->Router = NetGetUint32 (Data);
    break;

  case DHCP_TAG_LEASE:
    Para->Lease = NetGetUint32 (Data);
    break;

  case DHCP_TAG_OVERLOAD:
    Para->Overload = *Data;

    if ((Para->Overload < 1) || (Para->Overload > 3)) {
      return EFI_INVALID_PARAMETER;
    }
    break;

  case DHCP_TAG_TYPE:
    Para->DhcpType = *Data;

    if ((Para->DhcpType < 1) || (Para->DhcpType > 9)) {
      return EFI_INVALID_PARAMETER;
    }
    break;

  case DHCP_TAG_SERVER_ID:
    Para->ServerId = NetGetUint32 (Data);
    break;

  case DHCP_TAG_T1:
    Para->T1 = NetGetUint32 (Data);
    break;

  case DHCP_TAG_T2:
    Para->T2 = NetGetUint32 (Data);
    break;
  }

  return EFI_SUCCESS;
}

STATIC
EFI_STATUS
DhcpIterateBufferOptions (
  IN  UINT8                 *Buffer,
  IN  INTN                  BufLen,
  IN  DHCP_CHECK_OPTION     Check,            OPTIONAL
  IN  VOID                  *Context,
  OUT UINT8                 *Overload         OPTIONAL
  )
/*++

Routine Description:

  Inspect all the options in a single buffer. DHCP options may be contained
  in several buffers, such as the BOOTP options filed, boot file or server
  name. Each option buffer is required to end with DHCP_TAG_EOP.

Arguments:

  Buffer    - The buffer which contains DHCP options
  BufLen    - The length of the buffer
  Check     - The callback function for each option found
  Context   - The opaque parameter for the Check
  Overload  - variable to save the value of DHCP_TAG_OVERLOAD option. 

Returns:

  EFI_SUCCESS           - All the options are valid
  EFI_INVALID_PARAMETER - The options are mal-formated.

--*/
{
  INTN                      Cur;
  UINT8                     Tag;
  UINT8                     Len;

  Cur = 0;

  while (Cur < BufLen) {
    Tag = Buffer[Cur];

    if (Tag == DHCP_TAG_PAD) {
      Cur++;
      continue;
    } else if (Tag == DHCP_TAG_EOP) {
      return EFI_SUCCESS;
    }

    Cur++;
    
    if (Cur == BufLen) {
      return EFI_INVALID_PARAMETER;
    }

    Len = Buffer[Cur++];
    
    if (Cur + Len > BufLen) {
      return EFI_INVALID_PARAMETER;
    }

    if ((Tag == DHCP_TAG_OVERLOAD) && (Overload != NULL)) {
      if (Len != 1) {
        return EFI_INVALID_PARAMETER;
      }

      *Overload = Buffer[Cur];
    }

    if ((Check != NULL) && EFI_ERROR (Check (Tag, Len, Buffer + Cur, Context))) {
      return EFI_INVALID_PARAMETER;
    }

    Cur += Len;
  }
  
  //
  // Each option buffer is expected to end with an EOP
  //
  return EFI_INVALID_PARAMETER;
}

EFI_STATUS
DhcpIterateOptions (
  IN  EFI_DHCP4_PACKET      *Packet,
  IN  DHCP_CHECK_OPTION     Check,        OPTIONAL
  IN  VOID                  *Context
  )
/*++

Routine Description:

  Iterate through a DHCP message to visit each option. First inspect
  all the options in the OPTION field. Then if overloaded, inspect
  the options in FILENAME and SERVERNAME fields. One option may be
  encoded in several places. See RFC 3396 Encoding Long Options in DHCP

Arguments:

  Packet  - The DHCP packet to check the options for
  Check   - The callback function to be called for each option found
  Context - The opaque parameter for Check

Returns:

  EFI_SUCCESS - The DHCP packet's options are well formated
  Others      - The DHCP packet's options are not well formated

--*/
{
  EFI_STATUS                Status;
  UINT8                     Overload;

  Overload = 0;

  Status   = DhcpIterateBufferOptions (
               Packet->Dhcp4.Option,
               Packet->Length - sizeof (EFI_DHCP4_HEADER) - sizeof (UINT32),
               Check,
               Context,
               &Overload
               );

  if (EFI_ERROR (Status)) {
    return Status;
  }

  if ((Overload == DHCP_OVERLOAD_FILENAME) || (Overload == DHCP_OVERLOAD_BOTH)) {
    Status = DhcpIterateBufferOptions (
               Packet->Dhcp4.Header.BootFileName,
               128,
               Check,
               Context,
               NULL
               );

    if (EFI_ERROR (Status)) {
      return Status;
    }
  }

  if ((Overload == DHCP_OVERLOAD_SVRNAME) || (Overload == DHCP_OVERLOAD_BOTH)) {
    Status = DhcpIterateBufferOptions (
               Packet->Dhcp4.Header.ServerName,
               64,
               Check,
               Context,
               NULL
               );

    if (EFI_ERROR (Status)) {
      return Status;
    }
  }

  return EFI_SUCCESS;
}

STATIC
EFI_STATUS