pxedhcp4run.c

来自「EFI BIOS是Intel提出的下一代的BIOS标准。这里上传的Edk源代码是」· C语言 代码 · 共 196 行

/*++

Copyright (c) 2004, 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:
  PxeDhcp4Run.c
  
Abstract:
  Simplified entry point for starting basic PxeDhcp4 client operation.

--*/

#include "PxeDhcp4.h"

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
EFI_STATUS
EFIAPI
PxeDhcp4Run (
  IN EFI_PXE_DHCP4_PROTOCOL *This,
  IN OPTIONAL UINTN                  OpLen,
  IN OPTIONAL VOID                   *OpList
  )
{
  PXE_DHCP4_PRIVATE_DATA  *Private;
  DHCP4_PACKET            *offer_list;
  EFI_STATUS              efi_status;
  EFI_IP_ADDRESS          zero_ip;
  UINTN                   offers;
  UINTN                   timeout;
  UINTN                   n;
  UINT16                  seconds;

  //
  // Validate parameters.
  //
  if (This == NULL || (OpLen != 0 && OpList == NULL) || (OpLen == 0 && OpList != NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  for (n = 0; n < OpLen;) {
    switch (((UINT8 *) OpList)[n]) {
    case DHCP4_PAD:
      ++n;
      continue;

    case DHCP4_END:
      ++n;
      break;

    default:
      n += 2 + ((UINT8 *) OpList)[n + 1];
      continue;
    }

    break;
  }

  if (n != OpLen) {
    return EFI_INVALID_PARAMETER;
  }
  //
  // Get pointer to instance data.
  //
  Private = PXE_DHCP4_PRIVATE_DATA_FROM_THIS (This);

  if (Private == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  if (Private->PxeBc == NULL) {
    return EFI_DEVICE_ERROR;
  }
  //
  // Initialize DHCP discover packet.
  //
  efi_status = PxeDhcp4Setup (This, NULL);

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

  for (n = 0; n < OpLen;) {
    switch (((UINT8 *) OpList)[n]) {
    case DHCP4_PAD:
      ++n;
      continue;

    case DHCP4_END:
      ++n;
      break;

    default:
      efi_status = add_opt (
                    &This->Data->Discover,
                    (DHCP4_OP *) &(((UINT8 *) OpList)[n])
                    );

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

      n += 2 + ((UINT8 *) OpList)[n + 1];
      continue;
    }

    break;
  }
  //
  // Basic DHCP D.O.R.A.
  // 1, 2, 4, 8, 16 & 32 second timeouts.
  // Callback routine can be used to break out earlier.
  //
  EfiZeroMem (&zero_ip, sizeof (EFI_IP_ADDRESS));

  for (timeout = 1;;) {
    //
    // Broadcast DHCP discover and wait for DHCP offers.
    //
    efi_status = PxeDhcp4Init (This, timeout, &offers, &offer_list);

    switch (efi_status) {
    case EFI_NO_RESPONSE:
    case EFI_TIMEOUT:
    case EFI_SUCCESS:
      break;

    case EFI_ABORTED:
    default:
      return efi_status;
    }
    //
    // Try to select from each DHCP or BOOTP offer.
    //
    for (n = 0; n < offers; ++n) {
      //
      // Ignore proxyDHCP offers.
      //
      if (!EfiCompareMem (&offer_list[n].dhcp4.yiaddr, &zero_ip, 4)) {
        continue;
      }
      //
      // Issue DHCP Request and wait for DHCP Ack/Nak.
      //
      efi_status = PxeDhcp4Select (
                    This,
                    timeout,
                    &offer_list[n]
                    );

      if (EFI_ERROR (efi_status)) {
        continue;
      }
      //
      // Exit when we have got our DHCP Ack.
      //
      if (This->Data->IsAck) {
        return EFI_SUCCESS;
      }
    }
    //
    // No DHCP Acks.  Release DHCP Offer list storage.
    //
    if (offer_list != NULL) {
      gBS->FreePool (offer_list);
      offer_list = NULL;
    }
    //
    // Try again until we have used up >= DHCP4_MAX_SECONDS.
    //
    if ((timeout <<= 1) > DHCP4_MAX_SECONDS) {
      if (!EFI_ERROR (efi_status)) {
        efi_status = EFI_TIMEOUT;
      }

      return efi_status;
    }
    //
    // Next timeout value.
    //
    EfiCopyMem (&seconds, &This->Data->Discover.dhcp4.secs, 2);

    seconds = htons (htons (seconds) + timeout);

    EfiCopyMem (&This->Data->Discover.dhcp4.secs, &seconds, 2);
  }
}

/* eof - PxeDhcp4Run.c */