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 591 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 596 of file dhcp.h.

Referenced by dhcp_create_packet().

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 603 of file dhcp.h.

Referenced by dhcp_create_packet().

uint8_t dhcphdr::hlen

Hardware address length.

Definition at line 605 of file dhcp.h.

Referenced by dhcp_create_packet().

uint8_t dhcphdr::hops

Number of hops from server.

Definition at line 607 of file dhcp.h.

uint32_t dhcphdr::xid

Transaction ID.

Definition at line 609 of file dhcp.h.

Referenced by dhcp_create_packet(), and dhcp_deliver().

uint16_t dhcphdr::secs

Seconds since start of acquisition.

Definition at line 611 of file dhcp.h.

Referenced by dhcp_tx().

uint16_t dhcphdr::flags

Flags.

Definition at line 613 of file dhcp.h.

Referenced by dhcp_create_packet().

struct in_addr dhcphdr::ciaddr

"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 619 of file dhcp.h.

Referenced by create_fakepxebsack(), and dhcp_create_request().

struct in_addr dhcphdr::yiaddr

"Your" IP address

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

Definition at line 624 of file dhcp.h.

Referenced by dhcp_discovery_rx(), and dhcp_request_rx().

struct in_addr dhcphdr::siaddr

"Server" IP address

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

Definition at line 630 of file dhcp.h.

Referenced by dhcp_deliver(), and dhcp_has_pxeopts().

struct in_addr dhcphdr::giaddr

"Gateway" IP address

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

Definition at line 635 of file dhcp.h.

uint8_t dhcphdr::chaddr[16]

Client hardware address.

Definition at line 637 of file dhcp.h.

Referenced by cachedhcp_probe(), dhcp_create_packet(), and dhcp_deliver().

char dhcphdr::sname[64]

Server host name (null terminated)

This field may be overridden and contain DHCP options

Definition at line 642 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 647 of file dhcp.h.

uint32_t dhcphdr::magic

DHCP magic cookie.

Must have the value DHCP_MAGIC_COOKIE.

Definition at line 652 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 659 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/ipxe/dhcp.h