[mirror_edk2.git] / NetworkPkg / HttpBootDxe / HttpBootImpl.c

/** @file\r
  The implementation of EFI_LOAD_FILE_PROTOCOL for UEFI HTTP boot.\r
\r
Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>\r
This program and the accompanying materials are licensed and made available under \r
the terms and conditions of the BSD License that accompanies this distribution.  \r
The full text of the license may be found at\r
http://opensource.org/licenses/bsd-license.php.                                          \r
    \r
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     \r
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include "HttpBootDxe.h"\r
\r
/**\r
  Enable the use of UEFI HTTP boot function.\r
\r
  @param[in]    Private            The pointer to the driver's private data.\r
\r
  @retval EFI_SUCCESS              HTTP boot was successfully enabled.\r
  @retval EFI_INVALID_PARAMETER    Private is NULL.\r
  @retval EFI_ALREADY_STARTED      The driver is already in started state.\r
  \r
**/\r
EFI_STATUS\r
HttpBootStart (\r
  IN HTTP_BOOT_PRIVATE_DATA           *Private\r
  )\r
{\r
  UINTN          Index;\r
\r
  if (Private == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  if (Private->Started) {\r
    return EFI_ALREADY_STARTED;\r
  }\r
\r
  if (!Private->UsingIpv6) {\r
    //\r
    // Init the content of cached DHCP offer list.\r
    //\r
    ZeroMem (Private->OfferBuffer, sizeof (Private->OfferBuffer));\r
    for (Index = 0; Index < HTTP_BOOT_OFFER_MAX_NUM; Index++) {\r
      Private->OfferBuffer[Index].Dhcp4.Packet.Offer.Size = HTTP_BOOT_DHCP4_PACKET_MAX_SIZE;\r
    }\r
  } else {\r
    ASSERT (FALSE);\r
  }\r
\r
  Private->Started = TRUE;\r
\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  Attempt to complete a DHCPv4 D.O.R.A sequence to retrieve the boot resource information.\r
\r
  @param[in]    Private            The pointer to the driver's private data.\r
\r
  @retval EFI_SUCCESS              Boot info was successfully retrieved.\r
  @retval EFI_INVALID_PARAMETER    Private is NULL.\r
  @retval EFI_NOT_STARTED          The driver is in stopped state.\r
  @retval EFI_DEVICE_ERROR         An unexpected network error occurred.\r
  @retval Others                   Other errors as indicated.\r
  \r
**/\r
EFI_STATUS\r
HttpBootDhcp (\r
  IN HTTP_BOOT_PRIVATE_DATA           *Private\r
  )\r
{\r
  EFI_STATUS                Status;\r
\r
  if (Private == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
  \r
  if (!Private->Started) {\r
    return EFI_NOT_STARTED;\r
  }\r
\r
  Status = EFI_DEVICE_ERROR;\r
\r
  if (!Private->UsingIpv6) {\r
    Status = HttpBootDhcp4Dora (Private);\r
  } else {\r
    ASSERT (FALSE);\r
  }\r
\r
  return Status;\r
}\r
\r
/**\r
  Attempt to download the boot file through HTTP message exchange.\r
\r
  @param[in]          Private         The pointer to the driver's private data.\r
  @param[in, out]     BufferSize      On input the size of Buffer in bytes. On output with a return\r
                                      code of EFI_SUCCESS, the amount of data transferred to\r
                                      Buffer. On output with a return code of EFI_BUFFER_TOO_SMALL,\r
                                      the size of Buffer required to retrieve the requested file.\r
  @param[in]          Buffer          The memory buffer to transfer the file to. If Buffer is NULL,\r
                                      then the size of the requested file is returned in\r
                                      BufferSize.\r
\r
  @retval EFI_SUCCESS                 Boot file was loaded successfully.\r
  @retval EFI_INVALID_PARAMETER       Private is NULL.\r
  @retval EFI_NOT_STARTED             The driver is in stopped state.\r
  @retval EFI_BUFFER_TOO_SMALL        The BufferSize is too small to read the boot file. BufferSize has \r
                                      been updated with the size needed to complete the request.\r
  @retval EFI_DEVICE_ERROR            An unexpected network error occurred.\r
  @retval Others                      Other errors as indicated.\r
  \r
**/\r
EFI_STATUS\r
HttpBootLoadFile (\r
  IN     HTTP_BOOT_PRIVATE_DATA       *Private,\r
  IN OUT UINTN                        *BufferSize,\r
  IN     VOID                         *Buffer       OPTIONAL\r
  )\r
{\r
  EFI_STATUS             Status;\r
\r
  if (Private == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
  \r
  if (!Private->Started) {\r
    return EFI_NOT_STARTED;\r
  }\r
\r
  Status = EFI_DEVICE_ERROR;\r
\r
  if (Private->BootFileUri == NULL) {\r
    //\r
    // Parse the cached offer to get the boot file URL first.\r
    //\r
    Status = HttpBootDiscoverBootInfo (Private);\r
    if (EFI_ERROR (Status)) {\r
      return Status;\r
    }\r
  }\r
\r
  if (!Private->HttpCreated) {\r
    //\r
    // Create HTTP child.\r
    //\r
    Status = HttpBootCreateHttpIo (Private);\r
    if (EFI_ERROR (Status)) {\r
      return Status;\r
    }\r
  }\r
\r
  if (Private->BootFileSize == 0) {\r
    //\r
    // Discover the information about the bootfile if we haven't.\r
    //\r
\r
    //\r
    // Try to use HTTP HEAD method.\r
    //\r
    Status = HttpBootGetBootFile (\r
               Private,\r
               TRUE,\r
               &Private->BootFileSize,\r
               NULL\r
               );\r
    if (EFI_ERROR (Status) && Status != EFI_BUFFER_TOO_SMALL) {\r
      //\r
      // Failed to get file size by HEAD method, may be trunked encoding, try HTTP GET method.\r
      //\r
      ASSERT (Private->BootFileSize == 0);\r
      Status = HttpBootGetBootFile (\r
                 Private,\r
                 FALSE,\r
                 &Private->BootFileSize,\r
                 NULL\r
                 );\r
      if (EFI_ERROR (Status) && Status != EFI_BUFFER_TOO_SMALL) {\r
        return Status;\r
      }\r
    }\r
  }\r
\r
  if (*BufferSize < Private->BootFileSize) {\r
    *BufferSize = Private->BootFileSize;\r
    return EFI_BUFFER_TOO_SMALL;\r
  }\r
\r
  //\r
  // Load the boot file into Buffer\r
  //\r
  return  HttpBootGetBootFile (\r
            Private,\r
            FALSE,\r
            BufferSize,\r
            Buffer\r
            );\r
}\r
\r
/**\r
  Disable the use of UEFI HTTP boot function.\r
\r
  @param[in]    Private            The pointer to the driver's private data.\r
\r
  @retval EFI_SUCCESS              HTTP boot was successfully disabled.\r
  @retval EFI_NOT_STARTED          The driver is already in stopped state.\r
  @retval EFI_INVALID_PARAMETER    Private is NULL.\r
  @retval Others                   Unexpected error when stop the function.\r
  \r
**/\r
EFI_STATUS\r
HttpBootStop (\r
  IN HTTP_BOOT_PRIVATE_DATA           *Private\r
  )\r
{\r
  UINTN            Index;\r
\r
  if (Private == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
  \r
  if (!Private->Started) {\r
    return EFI_NOT_STARTED;\r
  }\r
  \r
  if (Private->HttpCreated) {\r
    HttpIoDestroyIo (&Private->HttpIo);\r
    Private->HttpCreated = FALSE;\r
  }\r
  \r
  Private->Started = FALSE;\r
  ZeroMem (&Private->StationIp, sizeof (EFI_IP_ADDRESS));\r
  ZeroMem (&Private->SubnetMask, sizeof (EFI_IP_ADDRESS));\r
  ZeroMem (&Private->GatewayIp, sizeof (EFI_IP_ADDRESS));\r
  Private->Port = 0;\r
  Private->BootFileUri = NULL;\r
  Private->BootFileUriParser = NULL;\r
  Private->BootFileSize = 0;\r
  Private->SelectIndex = 0;\r
  Private->SelectProxyType = HttpOfferTypeMax;\r
\r
  if (!Private->UsingIpv6) {\r
    //\r
    // Stop and release the DHCP4 child.\r
    //\r
    Private->Dhcp4->Stop (Private->Dhcp4);\r
    Private->Dhcp4->Configure (Private->Dhcp4, NULL);\r
\r
    for (Index = 0; Index < HTTP_BOOT_OFFER_MAX_NUM; Index++) {\r
      if (Private->OfferBuffer[Index].Dhcp4.UriParser) {\r
        HttpUrlFreeParser (Private->OfferBuffer[Index].Dhcp4.UriParser);\r
      }\r
    }\r
  } else {\r
    ASSERT (FALSE);\r
  }\r
  \r
  ZeroMem (Private->OfferBuffer, sizeof (Private->OfferBuffer));\r
  Private->OfferNum = 0;\r
  ZeroMem (Private->OfferCount, sizeof (Private->OfferCount));\r
  ZeroMem (Private->OfferIndex, sizeof (Private->OfferIndex));\r
\r
  return EFI_SUCCESS;\r
}\r
\r
/**\r
  Causes the driver to load a specified file.\r
\r
  @param  This       Protocol instance pointer.\r
  @param  FilePath   The device specific path of the file to load.\r
  @param  BootPolicy If TRUE, indicates that the request originates from the\r
                     boot manager is attempting to load FilePath as a boot\r
                     selection. If FALSE, then FilePath must match as exact file\r
                     to be loaded.\r
  @param  BufferSize On input the size of Buffer in bytes. On output with a return\r
                     code of EFI_SUCCESS, the amount of data transferred to\r
                     Buffer. On output with a return code of EFI_BUFFER_TOO_SMALL,\r
                     the size of Buffer required to retrieve the requested file.\r
  @param  Buffer     The memory buffer to transfer the file to. IF Buffer is NULL,\r
                     then the size of the requested file is returned in\r
                     BufferSize.\r
\r
  @retval EFI_SUCCESS           The file was loaded.\r
  @retval EFI_UNSUPPORTED       The device does not support the provided BootPolicy\r
  @retval EFI_INVALID_PARAMETER FilePath is not a valid device path, or\r
                                BufferSize is NULL.\r
  @retval EFI_NO_MEDIA          No medium was present to load the file.\r
  @retval EFI_DEVICE_ERROR      The file was not loaded due to a device error.\r
  @retval EFI_NO_RESPONSE       The remote system did not respond.\r
  @retval EFI_NOT_FOUND         The file was not found.\r
  @retval EFI_ABORTED           The file load process was manually cancelled.\r
  @retval EFI_BUFFER_TOO_SMALL  The BufferSize is too small to read the current directory entry.\r
                                BufferSize has been updated with the size needed to complete\r
                                the request.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
HttpBootDxeLoadFile (\r
  IN EFI_LOAD_FILE_PROTOCOL           *This,\r
  IN EFI_DEVICE_PATH_PROTOCOL         *FilePath,\r
  IN BOOLEAN                          BootPolicy,\r
  IN OUT UINTN                        *BufferSize,\r
  IN VOID                             *Buffer OPTIONAL\r
  )\r
{\r
  HTTP_BOOT_PRIVATE_DATA        *Private;\r
  BOOLEAN                       MediaPresent;\r
  EFI_STATUS                    Status;\r
\r
  if (This == NULL || BufferSize == NULL) {\r
    return EFI_INVALID_PARAMETER;\r
  }\r
\r
  //\r
  // Only support BootPolicy\r
  //\r
  if (!BootPolicy) {\r
    return EFI_UNSUPPORTED;\r
  }\r
\r
  Private = HTTP_BOOT_PRIVATE_DATA_FROM_LOADFILE (This);\r
\r
  //\r
  // Check media status before HTTP boot start\r
  //\r
  MediaPresent = TRUE;\r
  NetLibDetectMedia (Private->Controller, &MediaPresent);\r
  if (!MediaPresent) {\r
    return EFI_NO_MEDIA;\r
  }\r
\r
  //\r
  // Initialize HTTP boot and load the boot file.\r
  //\r
  Status = HttpBootStart (Private);\r
  if (Status == EFI_SUCCESS || Status == EFI_ALREADY_STARTED) {\r
    Status = HttpBootLoadFile (Private, BufferSize, Buffer);\r
  }\r
\r
  if (Status != EFI_SUCCESS && Status != EFI_BUFFER_TOO_SMALL) {\r
    HttpBootStop (Private);\r
  } else {\r
    //\r
    // Stop and release the DHCP4 child.\r
    //\r
    Private->Dhcp4->Stop (Private->Dhcp4);\r
    Private->Dhcp4->Configure (Private->Dhcp4, NULL);\r
  }\r
\r
  return Status;\r
}\r
\r
///\r
/// Load File Protocol instance\r
///\r
GLOBAL_REMOVE_IF_UNREFERENCED \r
EFI_LOAD_FILE_PROTOCOL  gHttpBootDxeLoadFile = {\r
  HttpBootDxeLoadFile\r
};\r
Commit	Line	Data
d933e70a JW	1	/** @file\r
	2	The implementation of EFI_LOAD_FILE_PROTOCOL for UEFI HTTP boot.\r
	3	\r
	4	Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>\r
	5	This program and the accompanying materials are licensed and made available under \r
	6	the terms and conditions of the BSD License that accompanies this distribution. \r
	7	The full text of the license may be found at\r
	8	http://opensource.org/licenses/bsd-license.php. \r
	9	\r
	10	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, \r
	11	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	12	\r
	13	**/\r
	14	\r
	15	#include "HttpBootDxe.h"\r
	16	\r
	17	/**\r
	18	Enable the use of UEFI HTTP boot function.\r
	19	\r
	20	@param[in] Private The pointer to the driver's private data.\r
	21	\r
	22	@retval EFI_SUCCESS HTTP boot was successfully enabled.\r
	23	@retval EFI_INVALID_PARAMETER Private is NULL.\r
	24	@retval EFI_ALREADY_STARTED The driver is already in started state.\r
	25	\r
	26	**/\r
	27	EFI_STATUS\r
	28	HttpBootStart (\r
	29	IN HTTP_BOOT_PRIVATE_DATA *Private\r
	30	)\r
	31	{\r
	32	UINTN Index;\r
	33	\r
	34	if (Private == NULL) {\r
	35	return EFI_INVALID_PARAMETER;\r
	36	}\r
	37	\r
	38	if (Private->Started) {\r
	39	return EFI_ALREADY_STARTED;\r
	40	}\r
	41	\r
	42	if (!Private->UsingIpv6) {\r
	43	//\r
	44	// Init the content of cached DHCP offer list.\r
	45	//\r
	46	ZeroMem (Private->OfferBuffer, sizeof (Private->OfferBuffer));\r
	47	for (Index = 0; Index < HTTP_BOOT_OFFER_MAX_NUM; Index++) {\r
	48	Private->OfferBuffer[Index].Dhcp4.Packet.Offer.Size = HTTP_BOOT_DHCP4_PACKET_MAX_SIZE;\r
	49	}\r
	50	} else {\r
	51	ASSERT (FALSE);\r
	52	}\r
	53	\r
	54	Private->Started = TRUE;\r
	55	\r
	56	return EFI_SUCCESS;\r
	57	}\r
	58	\r
	59	/**\r
	60	Attempt to complete a DHCPv4 D.O.R.A sequence to retrieve the boot resource information.\r
	61	\r
	62	@param[in] Private The pointer to the driver's private data.\r
	63	\r
	64	@retval EFI_SUCCESS Boot info was successfully retrieved.\r
65	@retval EFI_INVALID_PARAMETER Private is NULL.\r
66	@retval EFI_NOT_STARTED The driver is in stopped state.\r
67	@retval EFI_DEVICE_ERROR An unexpected network error occurred.\r
68	@retval Others Other errors as indicated.\r
69	\r
70	**/\r
71	EFI_STATUS\r
72	HttpBootDhcp (\r
73	IN HTTP_BOOT_PRIVATE_DATA *Private\r
74	)\r
75	{\r
76	EFI_STATUS Status;\r
77	\r
78	if (Private == NULL) {\r
79	return EFI_INVALID_PARAMETER;\r
80	}\r
81	\r
82	if (!Private->Started) {\r
83	return EFI_NOT_STARTED;\r
84	}\r
85	\r
86	Status = EFI_DEVICE_ERROR;\r
87	\r
88	if (!Private->UsingIpv6) {\r
89	Status = HttpBootDhcp4Dora (Private);\r
90	} else {\r
91	ASSERT (FALSE);\r
92	}\r
93	\r
94	return Status;\r
95	}\r
96	\r
97	/**\r
98	Attempt to download the boot file through HTTP message exchange.\r
99	\r
100	@param[in] Private The pointer to the driver's private data.\r
101	@param[in, out] BufferSize On input the size of Buffer in bytes. On output with a return\r
102	code of EFI_SUCCESS, the amount of data transferred to\r
103	Buffer. On output with a return code of EFI_BUFFER_TOO_SMALL,\r
104	the size of Buffer required to retrieve the requested file.\r
105	@param[in] Buffer The memory buffer to transfer the file to. If Buffer is NULL,\r
106	then the size of the requested file is returned in\r
107	BufferSize.\r
108	\r
109	@retval EFI_SUCCESS Boot file was loaded successfully.\r
110	@retval EFI_INVALID_PARAMETER Private is NULL.\r
111	@retval EFI_NOT_STARTED The driver is in stopped state.\r
112	@retval EFI_BUFFER_TOO_SMALL The BufferSize is too small to read the boot file. BufferSize has \r
113	been updated with the size needed to complete the request.\r
114	@retval EFI_DEVICE_ERROR An unexpected network error occurred.\r
115	@retval Others Other errors as indicated.\r
116	\r
117	**/\r
118	EFI_STATUS\r
119	HttpBootLoadFile (\r
120	IN HTTP_BOOT_PRIVATE_DATA *Private,\r
121	IN OUT UINTN *BufferSize,\r
122	IN VOID *Buffer OPTIONAL\r
123	)\r
124	{\r
125	EFI_STATUS Status;\r
126	\r
127	if (Private == NULL) {\r
128	return EFI_INVALID_PARAMETER;\r
129	}\r
130	\r
131	if (!Private->Started) {\r
132	return EFI_NOT_STARTED;\r
133	}\r
134	\r
135	Status = EFI_DEVICE_ERROR;\r
136	\r
137	if (Private->BootFileUri == NULL) {\r
138	//\r
139	// Parse the cached offer to get the boot file URL first.\r
140	//\r
141	Status = HttpBootDiscoverBootInfo (Private);\r
142	if (EFI_ERROR (Status)) {\r
143	return Status;\r
144	}\r
145	}\r
146	\r
147	if (!Private->HttpCreated) {\r
148	//\r
149	// Create HTTP child.\r
150	//\r
151	Status = HttpBootCreateHttpIo (Private);\r
152	if (EFI_ERROR (Status)) {\r
153	return Status;\r
154	}\r
155	}\r
156	\r
157	if (Private->BootFileSize == 0) {\r
158	//\r
159	// Discover the information about the bootfile if we haven't.\r
160	//\r
161	\r
162	//\r
163	// Try to use HTTP HEAD method.\r
164	//\r
165	Status = HttpBootGetBootFile (\r
166	Private,\r
167	TRUE,\r
168	&Private->BootFileSize,\r
169	NULL\r
170	);\r
171	if (EFI_ERROR (Status) && Status != EFI_BUFFER_TOO_SMALL) {\r
172	//\r
173	// Failed to get file size by HEAD method, may be trunked encoding, try HTTP GET method.\r
174	//\r
175	ASSERT (Private->BootFileSize == 0);\r
176	Status = HttpBootGetBootFile (\r
177	Private,\r
178	FALSE,\r
179	&Private->BootFileSize,\r
180	NULL\r
181	);\r
182	if (EFI_ERROR (Status) && Status != EFI_BUFFER_TOO_SMALL) {\r
183	return Status;\r
184	}\r
185	}\r
186	}\r
187	\r
188	if (*BufferSize < Private->BootFileSize) {\r
189	*BufferSize = Private->BootFileSize;\r
190	return EFI_BUFFER_TOO_SMALL;\r
191	}\r
192	\r
193	//\r
194	// Load the boot file into Buffer\r
195	//\r
196	return HttpBootGetBootFile (\r
197	Private,\r
198	FALSE,\r
199	BufferSize,\r
200	Buffer\r
201	);\r
202	}\r
203	\r
204	/**\r
205	Disable the use of UEFI HTTP boot function.\r
206	\r
207	@param[in] Private The pointer to the driver's private data.\r
208	\r
209	@retval EFI_SUCCESS HTTP boot was successfully disabled.\r
210	@retval EFI_NOT_STARTED The driver is already in stopped state.\r
211	@retval EFI_INVALID_PARAMETER Private is NULL.\r
212	@retval Others Unexpected error when stop the function.\r
213	\r
214	**/\r
215	EFI_STATUS\r
216	HttpBootStop (\r
217	IN HTTP_BOOT_PRIVATE_DATA *Private\r
218	)\r
219	{\r
220	UINTN Index;\r
221	\r
222	if (Private == NULL) {\r
223	return EFI_INVALID_PARAMETER;\r
224	}\r
225	\r
226	if (!Private->Started) {\r
227	return EFI_NOT_STARTED;\r
228	}\r
229	\r
230	if (Private->HttpCreated) {\r
231	HttpIoDestroyIo (&Private->HttpIo);\r
232	Private->HttpCreated = FALSE;\r
233	}\r
234	\r
235	Private->Started = FALSE;\r
236	ZeroMem (&Private->StationIp, sizeof (EFI_IP_ADDRESS));\r
237	ZeroMem (&Private->SubnetMask, sizeof (EFI_IP_ADDRESS));\r
238	ZeroMem (&Private->GatewayIp, sizeof (EFI_IP_ADDRESS));\r
239	Private->Port = 0;\r
240	Private->BootFileUri = NULL;\r
241	Private->BootFileUriParser = NULL;\r
242	Private->BootFileSize = 0;\r
243	Private->SelectIndex = 0;\r
244	Private->SelectProxyType = HttpOfferTypeMax;\r
245	\r
246	if (!Private->UsingIpv6) {\r
247	//\r
248	// Stop and release the DHCP4 child.\r
249	//\r
250	Private->Dhcp4->Stop (Private->Dhcp4);\r
251	Private->Dhcp4->Configure (Private->Dhcp4, NULL);\r
252	\r
253	for (Index = 0; Index < HTTP_BOOT_OFFER_MAX_NUM; Index++) {\r
254	if (Private->OfferBuffer[Index].Dhcp4.UriParser) {\r
255	HttpUrlFreeParser (Private->OfferBuffer[Index].Dhcp4.UriParser);\r
256	}\r
257	}\r
258	} else {\r
259	ASSERT (FALSE);\r
260	}\r
261	\r
262	ZeroMem (Private->OfferBuffer, sizeof (Private->OfferBuffer));\r
263	Private->OfferNum = 0;\r
264	ZeroMem (Private->OfferCount, sizeof (Private->OfferCount));\r
265	ZeroMem (Private->OfferIndex, sizeof (Private->OfferIndex));\r
266	\r
267	return EFI_SUCCESS;\r
268	}\r
269	\r
270	/**\r
271	Causes the driver to load a specified file.\r
272	\r
273	@param This Protocol instance pointer.\r
274	@param FilePath The device specific path of the file to load.\r
275	@param BootPolicy If TRUE, indicates that the request originates from the\r
276	boot manager is attempting to load FilePath as a boot\r
277	selection. If FALSE, then FilePath must match as exact file\r
278	to be loaded.\r
279	@param BufferSize On input the size of Buffer in bytes. On output with a return\r
280	code of EFI_SUCCESS, the amount of data transferred to\r
281	Buffer. On output with a return code of EFI_BUFFER_TOO_SMALL,\r
282	the size of Buffer required to retrieve the requested file.\r
283	@param Buffer The memory buffer to transfer the file to. IF Buffer is NULL,\r
284	then the size of the requested file is returned in\r
285	BufferSize.\r
286	\r
287	@retval EFI_SUCCESS The file was loaded.\r
288	@retval EFI_UNSUPPORTED The device does not support the provided BootPolicy\r
289	@retval EFI_INVALID_PARAMETER FilePath is not a valid device path, or\r
290	BufferSize is NULL.\r
291	@retval EFI_NO_MEDIA No medium was present to load the file.\r
292	@retval EFI_DEVICE_ERROR The file was not loaded due to a device error.\r
293	@retval EFI_NO_RESPONSE The remote system did not respond.\r
294	@retval EFI_NOT_FOUND The file was not found.\r
295	@retval EFI_ABORTED The file load process was manually cancelled.\r
296	@retval EFI_BUFFER_TOO_SMALL The BufferSize is too small to read the current directory entry.\r
297	BufferSize has been updated with the size needed to complete\r
298	the request.\r
299	\r
300	**/\r
301	EFI_STATUS\r
302	EFIAPI\r
303	HttpBootDxeLoadFile (\r
304	IN EFI_LOAD_FILE_PROTOCOL *This,\r
305	IN EFI_DEVICE_PATH_PROTOCOL *FilePath,\r
306	IN BOOLEAN BootPolicy,\r
307	IN OUT UINTN *BufferSize,\r
308	IN VOID *Buffer OPTIONAL\r
309	)\r
310	{\r
311	HTTP_BOOT_PRIVATE_DATA *Private;\r
312	BOOLEAN MediaPresent;\r
313	EFI_STATUS Status;\r
314	\r
315	if (This == NULL \|\| BufferSize == NULL) {\r
316	return EFI_INVALID_PARAMETER;\r
317	}\r
318	\r
319	//\r
320	// Only support BootPolicy\r
321	//\r
322	if (!BootPolicy) {\r
323	return EFI_UNSUPPORTED;\r
324	}\r
325	\r
326	Private = HTTP_BOOT_PRIVATE_DATA_FROM_LOADFILE (This);\r
327	\r
328	//\r
329	// Check media status before HTTP boot start\r
330	//\r
331	MediaPresent = TRUE;\r
332	NetLibDetectMedia (Private->Controller, &MediaPresent);\r
333	if (!MediaPresent) {\r
334	return EFI_NO_MEDIA;\r
335	}\r
336	\r
337	//\r
338	// Initialize HTTP boot and load the boot file.\r
339	//\r
340	Status = HttpBootStart (Private);\r
341	if (Status == EFI_SUCCESS \|\| Status == EFI_ALREADY_STARTED) {\r
342	Status = HttpBootLoadFile (Private, BufferSize, Buffer);\r
343	}\r
344	\r
345	if (Status != EFI_SUCCESS && Status != EFI_BUFFER_TOO_SMALL) {\r
346	HttpBootStop (Private);\r
347	} else {\r
348	//\r
349	// Stop and release the DHCP4 child.\r
350	//\r
351	Private->Dhcp4->Stop (Private->Dhcp4);\r
352	Private->Dhcp4->Configure (Private->Dhcp4, NULL);\r
353	}\r
354	\r
355	return Status;\r
356	}\r
357	\r
358	///\r
359	/// Load File Protocol instance\r
360	///\r
361	GLOBAL_REMOVE_IF_UNREFERENCED \r
362	EFI_LOAD_FILE_PROTOCOL gHttpBootDxeLoadFile = {\r
363	HttpBootDxeLoadFile\r
364	};\r