join::DhcpMessage Class Reference

DHCP message codec. More...

#include <dhcp_message.hpp>

Public Types
enum	MessageType : uint8_t {   Discover = 1 , Offer = 2 , Request = 3 , Decline = 4 ,   Ack = 5 , Nak = 6 , Release = 7 , Inform = 8 }
	DHCP message types, RFC 2132 section 9.6. More...
enum	Operation : uint8_t { BootRequest = 1 , BootReply = 2 }
	DHCP operation codes. More...
enum	Flag : uint16_t { BroadcastFlag = 0x8000 }
	message flags. More...
enum	Overload : uint8_t { FileOverload = 1 , SnameOverload = 2 }
	option overload values. More...

Public Member Functions
ssize_t	serialize (const DhcpPacket &packet, char *data, size_t maxSize) const
	serialize a DHCP message into a buffer.
int	deserialize (DhcpPacket &packet, const char *data, size_t size) const
	deserialize a DHCP message from a buffer.

Static Public Attributes
static constexpr uint32_t	magicCookie = 0x63825363
	magic cookie introducing the option field.
static constexpr size_t	headerSize = 240
	size of the fixed part of a DHCP message, magic cookie included.
static constexpr size_t	minMsgSize = 300
	smallest message a BOOTP implementation accepts, RFC 951 and RFC 1542 section 2.1.
static constexpr size_t	maxOptionSize = 255
	biggest payload a single option can carry, its length field is one octet.

Protected Member Functions
int	serialize (const DhcpOption &options, char *&cur, const char *end) const
	serialize an option list into a buffer.
int	deserialize (DhcpOption &options, const char *cur, const char *end) const
	deserialize an option list from a buffer.

Static Protected Member Functions
static bool	writeHead (char *&cur, const char *end, uint8_t code, size_t size)
	write an option header into a buffer.
static bool	writeAddress (char *&cur, const char *end, const IpAddress &address)
	write an IPv4 address into a buffer.
static bool	readAddress (const char *&cur, const char *end, IpAddress &address)
	read an IPv4 address from a buffer.

Static Protected Attributes
static constexpr uint8_t	_ethernet = 1
	hardware address type of an Ethernet link.
static constexpr size_t	_chaddrSize = 16
	size of the client hardware address field.
static constexpr size_t	_snameSize = 64
	size of the server name field.
static constexpr size_t	_fileSize = 128
	size of the boot file name field.

Detailed Description

DHCP message codec.

Member Enumeration Documentation

Flag

enum join::DhcpMessage::Flag : uint16_t

message flags.

Enumerator
BroadcastFlag	the client asks to be answered by broadcast.

MessageType

enum join::DhcpMessage::MessageType : uint8_t

DHCP message types, RFC 2132 section 9.6.

Enumerator
Discover	a client looking for a server.
Offer	a server proposing an address.
Request	a client asking for an address.
Decline	a client refusing an address already in use.
Ack	a server confirming an address.
Nak	a server refusing a request.
Release	a client giving an address back.
Inform	a client asking for parameters only.

Operation

enum join::DhcpMessage::Operation : uint8_t

DHCP operation codes.

Enumerator
BootRequest	message sent by a client.
BootReply	message sent by a server.

Overload

enum join::DhcpMessage::Overload : uint8_t

option overload values.

Enumerator
FileOverload	the file field carries options.
SnameOverload	the sname field carries options.

Member Function Documentation

deserialize() [1/2]

int DhcpMessage::deserialize ( DhcpOption & options, const char * cur, const char * end ) const

protected

deserialize an option list from a buffer.

Parameters

options	option list to deserialize into.
cur	beginning of the options.
end	end of the options.

Returns

0 on success, -1 on failure.

deserialize() [2/2]

int join::DhcpMessage::deserialize ( DhcpPacket & packet, const char * data, size_t size ) const

inline

deserialize a DHCP message from a buffer.

Parameters

packet	DHCP message to deserialize into.
data	buffer holding the message to deserialize.
size	message size.

Returns

0 on success, -1 on failure.

readAddress()

static bool join::DhcpMessage::readAddress ( const char *& cur, const char * end, IpAddress & address )

inlinestaticprotected

read an IPv4 address from a buffer.

Parameters

cur	current position in the buffer, advanced on success.
end	end of the buffer.
address	address read.

Returns

true on success, false on failure.

serialize() [1/2]

int DhcpMessage::serialize ( const DhcpOption & options, char *& cur, const char * end ) const

protected

serialize an option list into a buffer.

Parameters

options	options to serialize.
cur	current position in the buffer, advanced on success.
end	end of the buffer.

Returns

0 on success, -1 on failure.

serialize() [2/2]

ssize_t join::DhcpMessage::serialize ( const DhcpPacket & packet, char * data, size_t maxSize ) const

inline

serialize a DHCP message into a buffer.

Parameters

packet	DHCP message to serialize.
data	buffer to serialize the message into.
maxSize	buffer size.

Returns

the message size, -1 on failure.

writeAddress()

static bool join::DhcpMessage::writeAddress ( char *& cur, const char * end, const IpAddress & address )

inlinestaticprotected

write an IPv4 address into a buffer.

Parameters

cur	current position in the buffer, advanced on success.
end	end of the buffer.
address	address to write.

Returns

true on success, false if the buffer is too small.

writeHead()

bool DhcpMessage::writeHead ( char *& cur, const char * end, uint8_t code, size_t size )

staticprotected

write an option header into a buffer.

Parameters

cur	current position in the buffer, advanced on success.
end	end of the buffer.
code	option code.
size	option payload size.

Returns

true on success, false if the payload does not fit in an option or the header in the buffer.

Member Data Documentation

_chaddrSize

size_t join::DhcpMessage::_chaddrSize = 16

staticconstexprprotected

size of the client hardware address field.

_ethernet

uint8_t join::DhcpMessage::_ethernet = 1

staticconstexprprotected

hardware address type of an Ethernet link.

_fileSize

size_t join::DhcpMessage::_fileSize = 128

staticconstexprprotected

size of the boot file name field.

_snameSize

size_t join::DhcpMessage::_snameSize = 64

staticconstexprprotected

size of the server name field.

headerSize

size_t join::DhcpMessage::headerSize = 240

staticconstexpr

size of the fixed part of a DHCP message, magic cookie included.

magicCookie

uint32_t join::DhcpMessage::magicCookie = 0x63825363

staticconstexpr

magic cookie introducing the option field.

maxOptionSize

size_t join::DhcpMessage::maxOptionSize = 255

staticconstexpr

biggest payload a single option can carry, its length field is one octet.

minMsgSize

size_t join::DhcpMessage::minMsgSize = 300

staticconstexpr

smallest message a BOOTP implementation accepts, RFC 951 and RFC 1542 section 2.1.

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The documentation for this class was generated from the following files:

• fabric/include/join/dhcp_message.hpp
• fabric/src/dhcp_message.cpp