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/** @file
To validate, parse and process the DHCP options.
Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#ifndef __EFI_DHCP4_OPTION_H__
#define __EFI_DHCP4_OPTION_H__
///
/// DHCP option tags (types)
///
#define DHCP_OPTION_MAGIC 0x63538263 // Network byte order
#define DHCP_MAX_OPTIONS 256
//
// DHCP option types, this is used to validate the DHCP options.
//
#define DHCP_OPTION_SWITCH 1
#define DHCP_OPTION_INT8 2
#define DHCP_OPTION_INT16 3
#define DHCP_OPTION_INT32 4
#define DHCP_OPTION_IP 5
#define DHCP_OPTION_IPPAIR 6
//
// Value of DHCP overload option
//
#define DHCP_OVERLOAD_FILENAME 1
#define DHCP_OVERLOAD_SVRNAME 2
#define DHCP_OVERLOAD_BOTH 3
///
/// The DHCP option structure. This structure extends the EFI_DHCP_OPTION
/// structure to support options longer than 255 bytes, such as classless route.
///
typedef struct {
UINT8 Tag;
UINT16 Len;
UINT8 *Data;
} DHCP_OPTION;
///
/// Structures used to parse the DHCP options with RFC3396 support.
///
typedef struct {
UINT8 Index;
UINT16 Offset;
} DHCP_OPTION_COUNT;
typedef struct {
DHCP_OPTION_COUNT *OpCount;
DHCP_OPTION *Options;
UINT8 *Buf;
} DHCP_OPTION_CONTEXT;
///
/// The options that matters to DHCP driver itself. The user of
/// DHCP clients may be interested in other options, such as
/// classless route, who can parse the DHCP offer to get them.
///
typedef struct {
IP4_ADDR NetMask; // DHCP4_TAG_NETMASK
IP4_ADDR Router; // DHCP4_TAG_ROUTER, only the first router is used
//
// DHCP specific options
//
UINT8 DhcpType; // DHCP4_TAG_MSG_TYPE
UINT8 Overload; // DHCP4_TAG_OVERLOAD
IP4_ADDR ServerId; // DHCP4_TAG_SERVER_ID
UINT32 Lease; // DHCP4_TAG_LEASE
UINT32 T1; // DHCP4_TAG_T1
UINT32 T2; // DHCP4_TAG_T2
} DHCP_PARAMETER;
///
/// Structure used to describe and validate the format of DHCP options.
/// Type is the options' data type, such as DHCP_OPTION_INT8. MinOccur
/// is the minimum occurrence of this data type. MaxOccur is defined
/// similarly. If MaxOccur is -1, it means that there is no limit on the
/// maximum occurrence. Alert tells whether DHCP client should further
/// inspect the option to parse DHCP_PARAMETER.
///
typedef struct {
UINT8 Tag;
INTN Type;
INTN MinOccur;
INTN MaxOccur;
BOOLEAN Alert;
} DHCP_OPTION_FORMAT;
typedef
EFI_STATUS
(*DHCP_CHECK_OPTION) (
IN UINT8 Tag,
IN UINT8 Len,
IN UINT8 *Data,
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
@param[in] Packet The DHCP packet to check the options for
@param[in] Check The callback function to be called for each option
found
@param[in] Context The opaque parameter for Check
@retval EFI_SUCCESS The DHCP packet's options are well formatted
@retval EFI_INVALID_PARAMETER The DHCP packet's options are not well formatted
**/
EFI_STATUS
DhcpIterateOptions (
IN EFI_DHCP4_PACKET *Packet,
IN DHCP_CHECK_OPTION Check OPTIONAL,
IN VOID *Context
);
/**
Validate the packet's options. If necessary, allocate
and fill in the interested parameters.
@param[in] Packet The packet to validate the options
@param[out] Para The variable to save the DHCP parameters.
@retval EFI_OUT_OF_RESOURCES Failed to allocate memory to validate the packet.
@retval EFI_INVALID_PARAMETER The options are mal-formatted
@retval EFI_SUCCESS The options are parsed into OptionPoint
**/
EFI_STATUS
DhcpValidateOptions (
IN EFI_DHCP4_PACKET *Packet,
OUT DHCP_PARAMETER **Para OPTIONAL
);
/**
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.
@param[in] Packet The DHCP packet to parse the options
@param[out] Count The number of valid dhcp options present in the
packet
@param[out] OptionPoint The array that contains the DHCP options. Caller
should free it.
@retval EFI_NOT_FOUND Cannot find any option.
@retval EFI_OUT_OF_RESOURCES Failed to allocate memory to parse the packet.
@retval EFI_INVALID_PARAMETER The options are mal-formatted
@retval EFI_SUCCESS The options are parsed into OptionPoint
**/
EFI_STATUS
DhcpParseOption (
IN EFI_DHCP4_PACKET *Packet,
OUT INTN *Count,
OUT DHCP_OPTION **OptionPoint
);
/**
Append an option to the memory, if the option is longer than
255 bytes, splits it into several options.
@param[out] Buf The buffer to append the option to
@param[in] Tag The option's tag
@param[in] DataLen The length of the option's data
@param[in] Data The option's data
@return The position to append the next option
**/
UINT8 *
DhcpAppendOption (
OUT UINT8 *Buf,
IN UINT8 Tag,
IN UINT16 DataLen,
IN UINT8 *Data
);
/**
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.
@param[in] SeedPacket The seed packet to start with
@param[in] DeleteCount The number of options to delete
@param[in] DeleteList The options to delete from the packet
@param[in] AppendCount The number of options to append
@param[in] AppendList The options to append to the packet
@param[out] NewPacket The new packet, allocated and built by this
function.
@retval EFI_OUT_OF_RESOURCES Failed to allocate memory
@retval EFI_INVALID_PARAMETER The options in SeekPacket are mal-formatted
@retval EFI_SUCCESS The packet is build.
**/
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
);
#endif
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