#include "Dhcp4Impl.h"

Functions
DHCP_OPTION_FORMAT *	DhcpFindOptionFormat (IN UINT8 Tag)

BOOLEAN	DhcpOptionIsValid (IN DHCP_OPTION_FORMAT Format, IN UINT8 OptValue, IN INTN Len)

EFI_STATUS	DhcpGetParameter (IN UINT8 Tag, IN INTN Len, IN UINT8 Data, OUT DHCP_PARAMETER Para)

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

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

EFI_STATUS	DhcpGetOptionLen (IN UINT8 Tag, IN UINT8 Len, IN UINT8 Data, IN VOID Context)

EFI_STATUS	DhcpFillOption (IN UINT8 Tag, IN UINT8 Len, IN UINT8 Data, IN VOID Context)

EFI_STATUS	DhcpParseOption (IN EFI_DHCP4_PACKET Packet, OUT INTN Count, OUT DHCP_OPTION **OptionPoint)

EFI_STATUS	DhcpValidateOptions (IN EFI_DHCP4_PACKET Packet, OUT DHCP_PARAMETER *Para OPTIONAL)

UINT8 *	DhcpAppendOption (OUT UINT8 Buf, IN UINT8 Tag, IN UINT16 DataLen, IN UINT8 Data)

EFI_STATUS	DhcpBuild (IN EFI_DHCP4_PACKET SeedPacket, IN UINT32 DeleteCount, IN UINT8 DeleteList OPTIONAL, IN UINT32 AppendCount, IN EFI_DHCP4_PACKET_OPTION AppendList[] OPTIONAL, OUT EFI_DHCP4_PACKET *NewPacket)

Variables
DHCP_OPTION_FORMAT	DhcpOptionFormats []

Detailed Description

Function to validate, parse, process the DHCP options.

Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file Dhcp4Option.c.

Function Documentation

◆ DhcpAppendOption()

UINT8 * DhcpAppendOption	(	OUT UINT8 *	Buf,
		IN UINT8	Tag,
		IN UINT16	DataLen,
		IN UINT8 *	Data
	)

Append an option to the memory, if the option is longer than 255 bytes, splits it into several options.

Parameters

[out]	Buf	The buffer to append the option to
[in]	Tag	The option's tag
[in]	DataLen	The length of the option's data
[in]	Data	The option's data

Returns: The position to append the next option

Definition at line 727 of file Dhcp4Option.c.

◆ DhcpBuild()

EFI_STATUS DhcpBuild	(	IN EFI_DHCP4_PACKET *	SeedPacket,
		IN UINT32	DeleteCount,
		IN UINT8 *DeleteList	OPTIONAL,
		IN UINT32	AppendCount,
		IN EFI_DHCP4_PACKET_OPTION *AppendList[]	OPTIONAL,
		OUT EFI_DHCP4_PACKET **	NewPacket
	)

Build a new DHCP packet from a seed packet. Options may be deleted or appended. The caller should free the NewPacket when finished using it.

Parameters

[in]	SeedPacket	The seed packet to start with
[in]	DeleteCount	The number of options to delete
[in]	DeleteList	The options to delete from the packet
[in]	AppendCount	The number of options to append
[in]	AppendList	The options to append to the packet
[out]	NewPacket	The new packet, allocated and built by this function.

Return values

EFI_OUT_OF_RESOURCES	Failed to allocate memory
EFI_INVALID_PARAMETER	The options in SeekPacket are mal-formatted
EFI_SUCCESS	The packet is build.

Definition at line 770 of file Dhcp4Option.c.

◆ DhcpFillOption()

EFI_STATUS DhcpFillOption	(	IN UINT8	Tag,
		IN UINT8	Len,
		IN UINT8 *	Data,
		IN VOID *	Context
	)

Call back function to DhcpIterateOptions to consolidate each option's data. There are maybe several occurrence of the same option.

Parameters

[in]	Tag	The option to consolidate its data
[in]	Len	The length of option data
[in]	Data	The data of the option's current occurrence
[in]	Context	The context, which is DHCP_OPTION_CONTEXT. This array is just a wrap to pass THREE parameters.

Return values

EFI_SUCCESS It always returns EFI_SUCCESS

Definition at line 480 of file Dhcp4Option.c.

◆ DhcpFindOptionFormat()

DHCP_OPTION_FORMAT * DhcpFindOptionFormat ( IN UINT8 Tag )

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

Parameters

[in] Tag The option's tag.

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

Definition at line 114 of file Dhcp4Option.c.

◆ DhcpGetOptionLen()

EFI_STATUS DhcpGetOptionLen	(	IN UINT8	Tag,
		IN UINT8	Len,
		IN UINT8 *	Data,
		IN VOID *	Context
	)

Call back function to DhcpIterateOptions to compute each option's length. It just adds the data length of all the occurrences of this Tag. Context is an array of 256 DHCP_OPTION_COUNT.

Parameters

[in]	Tag	The current option to check
[in]	Len	The length of the option data
[in]	Data	The option data
[in]	Context	The context, which is a array of 256 DHCP_OPTION_COUNT.

Return values

EFI_SUCCESS It always returns EFI_SUCCESS.

Definition at line 451 of file Dhcp4Option.c.

◆ DhcpGetParameter()

EFI_STATUS DhcpGetParameter	(	IN UINT8	Tag,
		IN INTN	Len,
		IN UINT8 *	Data,
		OUT DHCP_PARAMETER *	Para
	)

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

Parameters

[in]	Tag	The DHCP option tag
[in]	Len	The length of the option
[in]	Data	The value of the DHCP option
[out]	Para	The variable to save the interested parameter

Return values

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

Definition at line 235 of file Dhcp4Option.c.

◆ DhcpIterateBufferOptions()

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

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 DHCP4_TAG_EOP.

Parameters

[in]	Buffer	The buffer which contains DHCP options
[in]	BufLen	The length of the buffer
[in]	Check	The callback function for each option found
[in]	Context	The opaque parameter for the Check
[out]	Overload	Variable to save the value of DHCP4_TAG_OVERLOAD option.

Return values

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

Definition at line 309 of file Dhcp4Option.c.

◆ DhcpIterateOptions()

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

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

Parameters

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

Return values

EFI_SUCCESS	The DHCP packet's options are well formatted
EFI_INVALID_PARAMETER	The DHCP packet's options are not well formatted

Definition at line 382 of file Dhcp4Option.c.

◆ DhcpOptionIsValid()

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

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

Parameters

[in]	Format	The option's format
[in]	OptValue	The value of the option
[in]	Len	The length of the option value

Return values

TRUE	The option is valid.
FALSE	Otherwise.

Definition at line 154 of file Dhcp4Option.c.

◆ DhcpParseOption()

EFI_STATUS DhcpParseOption	(	IN EFI_DHCP4_PACKET *	Packet,
		OUT INTN *	Count,
		OUT DHCP_OPTION **	OptionPoint
	)

Parse the options of a DHCP packet. It supports RFC 3396: Encoding Long Options in DHCP. That is, it will combine all the option value of all the occurrences of each option. A little bit of implementation: It adopts the "Key indexed counting" algorithm. First, it allocates an array of 256 DHCP_OPTION_COUNTs because DHCP option tag is encoded as a UINT8. It then iterates the DHCP packet to get data length of each option by calling DhcpIterOptions with DhcpGetOptionLen. Now, it knows the number of present options and their length. It allocates a array of DHCP_OPTION and a continuous buffer after the array to put all the options' data. Each option's data is pointed to by the Data field in DHCP_OPTION structure. At last, it call DhcpIterateOptions with DhcpFillOption to fill each option's data to its position in the buffer.

Parameters

[in]	Packet	The DHCP packet to parse the options
[out]	Count	The number of valid dhcp options present in the packet
[out]	OptionPoint	The array that contains the DHCP options. Caller should free it.

Return values

EFI_NOT_FOUND	Cannot find any option.
EFI_OUT_OF_RESOURCES	Failed to allocate memory to parse the packet.
EFI_INVALID_PARAMETER	The options are mal-formatted
EFI_SUCCESS	The options are parsed into OptionPoint

Definition at line 541 of file Dhcp4Option.c.

◆ DhcpValidateOptions()

EFI_STATUS DhcpValidateOptions	(	IN EFI_DHCP4_PACKET *	Packet,
		OUT DHCP_PARAMETER **Para	OPTIONAL
	)

Validate the packet's options. If necessary, allocate and fill in the interested parameters.

Parameters

[in]	Packet	The packet to validate the options
[out]	Para	The variable to save the DHCP parameters.

Return values

EFI_OUT_OF_RESOURCES	Failed to allocate memory to validate the packet.
EFI_INVALID_PARAMETER	The options are mal-formatted
EFI_SUCCESS	The options are parsed into OptionPoint

Definition at line 641 of file Dhcp4Option.c.

Variable Documentation

◆ DhcpOptionFormats

DHCP_OPTION_FORMAT DhcpOptionFormats[]

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.

Definition at line 16 of file Dhcp4Option.c.

Functions

Variables

Detailed Description

Function Documentation

◆ DhcpAppendOption()

◆ DhcpBuild()

◆ DhcpFillOption()

◆ DhcpFindOptionFormat()

◆ DhcpGetOptionLen()

◆ DhcpGetParameter()

◆ DhcpIterateBufferOptions()

◆ DhcpIterateOptions()

◆ DhcpOptionIsValid()

◆ DhcpParseOption()

◆ DhcpValidateOptions()

Variable Documentation

◆ DhcpOptionFormats