dhcp.h File Reference

#include "kernel.h"

Data Structures
struct	dhcp_packet_t
	Definition of a DHCP packet. More...

Macros
#define	DHCP_TRANSACTION_IDENTIFIER   0x55AA55AA
	Hard coded transaction identifier. More...

Enumerations
enum	dhcp_request_type_t { DHCP_REQUEST = 1 , DHCP_REPLY = 2 }
	Direction of DHCP packet, outbound are REQUES and inbound (from the server to client) are REPLY. More...
enum	dhcp_udp_ports_t { DHCP_DST_PORT = 68 , DHCP_SRC_PORT = 67 }
	source and destination UDP port numbers More...
enum	dhcp_packet_type_t {   DHCPDISCOVER = 1 , DHCPOFFER = 2 , DHCPREQUEST = 3 , DHCPDECLINE = 4 ,   DHCPACK = 5 , DHCPNAK = 6 , DHCPRELEASE = 7 , DHCPINFORM = 8 }
	Packet types inside the options, type 53. More...
enum	dhcp_option_type_t {   OPT_SUBNET = 1 , OPT_GATEWAY = 3 , OPT_DNS = 6 , OPT_HOSTNAME = 12 ,   OPT_DOMAIN = 15 , OPT_NBNS = 44 , OPT_NBDD = 45 , OPT_NETBIOS_NODE_TYPE = 46 ,   OPT_REQUESTED_IP = 50 , OPT_LEASE_TIME = 51 , OPT_TYPE = 53 , OPT_SERVER_IP = 54 ,   OPT_PARAMETER_REQUEST_LIST = 55 , OPT_MAX_DHCP_SIZE = 57 , OPT_CLIENT_MAC = 61 , OPT_END = 255 }
	Types of options in the options fields. More...

Functions
struct dhcp_packet_t	__attribute__ ((packed)) dhcp_packet_t
	Definition of a DHCP packet. More...
void	dhcp_discover ()
	Initiate DHCP discovery Non-blocking, establishes IP address in the background. Network and IP stack card must be initialised first. More...
void	dhcp_request (uint8_t *request_ip, uint32_t xid, uint32_t server_ip)
	send DHCPREQUEST packet. We send one on dhcp_discover() as DHCPDISCOVER then a second one as DHCPREQUEST once we are offered an IP address. More...
void *	get_dhcp_options (dhcp_packet_t *packet, uint8_t type)
	Get an option from a DHCP packet. More...
uint16_t	make_dhcp_packet (dhcp_packet_t *packet, uint8_t msg_type, uint8_t *request_ip, uint32_t xid, uint32_t server_ip)
	Build a DHCP packet. The contents of the options are built dynamically. More...

Variables
uint8_t	op
uint8_t	hardware_type
uint8_t	hardware_addr_len
uint8_t	hops
uint32_t	xid
uint16_t	seconds
uint16_t	flags
uint32_t	client_ip
uint32_t	your_ip
uint32_t	server_ip
uint32_t	relay_agent_ip
uint8_t	client_hardware_addr [16]
uint8_t	server_name [64]
uint8_t	boot_file [128]
uint8_t	options [128]

Detailed Description

Author

Craig Edwards (craig.nosp@m.edwa.nosp@m.rds@b.nosp@m.rain.nosp@m.box.c.nosp@m.c)

Copyright

Copyright (c) 2012-2023

Macro Definition Documentation

DHCP_TRANSACTION_IDENTIFIER

#define DHCP_TRANSACTION_IDENTIFIER   0x55AA55AA

Hard coded transaction identifier.

Enumeration Type Documentation

dhcp_option_type_t

enum dhcp_option_type_t

Types of options in the options fields.

Enumerator
OPT_SUBNET
OPT_GATEWAY
OPT_DNS
OPT_HOSTNAME
OPT_DOMAIN
OPT_NBNS
OPT_NBDD
OPT_NETBIOS_NODE_TYPE
OPT_REQUESTED_IP
OPT_LEASE_TIME
OPT_TYPE
OPT_SERVER_IP
OPT_PARAMETER_REQUEST_LIST
OPT_MAX_DHCP_SIZE
OPT_CLIENT_MAC
OPT_END

dhcp_packet_type_t

enum dhcp_packet_type_t

Packet types inside the options, type 53.

Enumerator
DHCPDISCOVER
DHCPOFFER
DHCPREQUEST
DHCPDECLINE
DHCPACK
DHCPNAK
DHCPRELEASE
DHCPINFORM

dhcp_request_type_t

enum dhcp_request_type_t

Direction of DHCP packet, outbound are REQUES and inbound (from the server to client) are REPLY.

Enumerator
DHCP_REQUEST
DHCP_REPLY

dhcp_udp_ports_t

enum dhcp_udp_ports_t

source and destination UDP port numbers

Enumerator
DHCP_DST_PORT
DHCP_SRC_PORT

Function Documentation

__attribute__()

struct dhcp_packet_t __attribute__

(

(packed)

)

Definition of a DHCP packet.

dhcp_discover()

void dhcp_discover

(

)

Initiate DHCP discovery Non-blocking, establishes IP address in the background. Network and IP stack card must be initialised first.

dhcp_request()

void dhcp_request	(	uint8_t *	request_ip,
		uint32_t	xid,
		uint32_t	server_ip
	)

send DHCPREQUEST packet. We send one on dhcp_discover() as DHCPDISCOVER then a second one as DHCPREQUEST once we are offered an IP address.

Parameters

request_ip	IP address we have been offered, if we have been offered an IP yet.
xid	request ID as set by us when we did DHCPDISCOVER
server_ip	server IP that sent the offer to us

get_dhcp_options()

void* get_dhcp_options	(	dhcp_packet_t *	packet,
		uint8_t	type
	)

Get an option from a DHCP packet.

Parameters

packet	raw packet
type	type to search for

Returns

void* raw option, size must be known to the caller!

make_dhcp_packet()

uint16_t make_dhcp_packet	(	dhcp_packet_t *	packet,
		uint8_t	msg_type,
		uint8_t *	request_ip,
		uint32_t	xid,
		uint32_t	server_ip
	)

Build a DHCP packet. The contents of the options are built dynamically.

Parameters

packet	Packet structure to fill
msg_type	Message type to build
request_ip	IP address we were offered
xid	Our request identifier
server_ip	IP of server that offered the configuration

Returns

packet size of constructed packet including options

Variable Documentation

boot_file

uint8_t boot_file[128]

client_hardware_addr

uint8_t client_hardware_addr[16]

client_ip

uint32_t client_ip

flags

uint16_t flags

hardware_addr_len

uint8_t hardware_addr_len

hardware_type

uint8_t hardware_type

hops

uint8_t hops

op

uint8_t op

options

uint8_t options[128]

relay_agent_ip

uint32_t relay_agent_ip

seconds

uint16_t seconds

server_ip

uint32_t server_ip

server_name

uint8_t server_name[64]

xid

uint32_t xid

your_ip

uint32_t your_ip