dhcphdr Struct Reference

A DHCP header. More...

#include <dhcp.h>

Data Fields
uint8_t	op
	Operation.
uint8_t	htype
	Hardware address type.
uint8_t	hlen
	Hardware address length.
uint8_t	hops
	Number of hops from server.
uint32_t	xid
	Transaction ID.
uint16_t	secs
	Seconds since start of acquisition.
uint16_t	flags
	Flags.
struct in_addr	ciaddr
	"Client" IP address
struct in_addr	yiaddr
	"Your" IP address
struct in_addr	siaddr
	"Server" IP address
struct in_addr	giaddr
	"Gateway" IP address
uint8_t	chaddr [16]
	Client hardware address.
char	sname [64]
	Server host name (null terminated).
char	file [128]
	Boot file name (null terminated).
uint32_t	magic
	DHCP magic cookie.
uint8_t	options [0]
	DHCP options.

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Detailed Description

A DHCP header.

Definition at line 502 of file dhcp.h.

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Field Documentation

uint8_t dhcphdr::op

Operation.

This must be either BOOTP_REQUEST or BOOTP_REPLY.

Definition at line 507 of file dhcp.h.

Referenced by dhcp_create_packet(), and pxenv_get_cached_info().

uint8_t dhcphdr::htype

Hardware address type.

This is an ARPHRD_XXX constant. Note that ARPHRD_XXX constants are nominally 16 bits wide; this could be considered to be a bug in the BOOTP/DHCP specification.

Definition at line 514 of file dhcp.h.

Referenced by dhcp_create_packet().

uint8_t dhcphdr::hlen

Hardware address length.

Definition at line 516 of file dhcp.h.

Referenced by dhcp_create_packet().

uint8_t dhcphdr::hops

Number of hops from server.

Definition at line 518 of file dhcp.h.

uint32_t dhcphdr::xid

Transaction ID.

Definition at line 520 of file dhcp.h.

Referenced by dhcp_create_packet(), and dhcp_deliver_iob().

uint16_t dhcphdr::secs

Seconds since start of acquisition.

Definition at line 522 of file dhcp.h.

uint16_t dhcphdr::flags

Flags.

Definition at line 524 of file dhcp.h.

Referenced by dhcp_create_packet().

struct in_addr dhcphdr::ciaddr [read]

"Client" IP address

This is filled in if the client already has an IP address assigned and can respond to ARP requests.

Definition at line 530 of file dhcp.h.

Referenced by dhcp_create_request().

struct in_addr dhcphdr::yiaddr [read]

"Your" IP address

This is the IP address assigned by the server to the client.

Definition at line 535 of file dhcp.h.

Referenced by dhcp_request_rx(), and dhcp_rx_offer().

struct in_addr dhcphdr::siaddr [read]

"Server" IP address

This is the IP address of the next server to be used in the boot process.

Definition at line 541 of file dhcp.h.

struct in_addr dhcphdr::giaddr [read]

"Gateway" IP address

This is the IP address of the DHCP relay agent, if any.

Definition at line 546 of file dhcp.h.

uint8_t dhcphdr::chaddr[16]

Client hardware address.

Definition at line 548 of file dhcp.h.

Referenced by dhcp_create_packet().

char dhcphdr::sname[64]

Server host name (null terminated).

This field may be overridden and contain DHCP options

Definition at line 553 of file dhcp.h.

char dhcphdr::file[128]

Boot file name (null terminated).

This field may be overridden and contain DHCP options

Definition at line 558 of file dhcp.h.

uint32_t dhcphdr::magic

DHCP magic cookie.

Must have the value DHCP_MAGIC_COOKIE.

Definition at line 563 of file dhcp.h.

Referenced by dhcp_create_packet().

uint8_t dhcphdr::options[0]

DHCP options.

Variable length; extends to the end of the packet. Minimum length (for the sake of sanity) is 1, to allow for a single DHCP_END tag.

Definition at line 570 of file dhcp.h.

Referenced by dhcp_create_packet(), and dhcppkt_init().

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The documentation for this struct was generated from the following file:

• include/gpxe/dhcp.h