DHCP Protocol Library (dhcp.c)
[Network Library]

Detailed Description

 #include "net/dhcp.h"

Description: This library provides a limited implementation of DHCP (Dynamic Host Configuration Protocol) as described in RFC2131. DHCP allows a network device to automatically obtain an IP address and other network configuration settings from a DHCP server.

Note:: This code is currently below version 1.0, and therefore is considered to be lacking in some functionality or documentation, or may not be fully tested. Nonetheless, you can expect most functions to work.

Data Structures

struct netBootpHeader

Bootp Header (DHCP is transported by BOOTP/UDP/IP). More...

struct netDhcpHeader

DHCP Header. More...

Defines

#define BOOTP_HEADER_LEN   236

length of BOOTP header not including options

#define BOOTP_OP_BOOTREQUEST   1

BOOTP Request operation (message from client to server).

#define BOOTP_OP_BOOTREPLY   2

BOOTP Reply operation (message from server to client).

#define BOOTP_HTYPE_ETHERNET   1

#define BOOTP_HLEN_ETHERNET   6

#define DHCP_HEADER_LEN   240

length of DHCP header not including options

#define DHCP_UDP_SERVER_PORT   67

UDP port where DHCP requests should be sent.

#define DHCP_UDP_CLIENT_PORT   68

UDP port clients will receive DHCP replies.

#define DHCP_OPT_PAD   0

token padding value (make be skipped)

#define DHCP_OPT_NETMASK   1

subnet mask client should use (4 byte mask)

#define DHCP_OPT_ROUTERS   3

routers client should use (IP addr list)

#define DHCP_OPT_TIMESERVERS   4

time servers client should use (IP addr list)

#define DHCP_OPT_NAMESERVERS   5

name servers client should use (IP addr list)

#define DHCP_OPT_DNSSERVERS   6

DNS servers client should use (IP addr list).

#define DHCP_OPT_HOSTNAME   12

host name client should use (string)

#define DHCP_OPT_DOMAINNAME   15

domain name client should use (string)

#define DHCP_OPT_REQUESTEDIP   50

IP address requested by client (IP address).

#define DHCP_OPT_LEASETIME   51

DHCP Lease Time (uint32 seconds).

#define DHCP_OPT_DHCPMSGTYPE   53

DHCP message type (1 byte).

#define DHCP_OPT_SERVERID   54

Server Identifier (IP address).

#define DHCP_OPT_PARAMREQLIST   55

Paramerter Request List (n OPT codes).

#define DHCP_OPT_RENEWALTIME   58

DHCP Lease Renewal Time (uint32 seconds).

#define DHCP_OPT_REBINDTIME   59

DHCP Lease Rebinding Time (uint32 seconds).

#define DHCP_OPT_END   255

token end value (marks end of options list)

#define DHCP_MSG_DHCPDISCOVER   1

DISCOVER is broadcast by client to solicit OFFER from any/all DHCP servers.

#define DHCP_MSG_DHCPOFFER   2

OFFER(s) are made to client by server to offer IP address and config info.

#define DHCP_MSG_DHCPREQUEST   3

REQUEST is made my client in response to best/favorite OFFER message.

#define DHCP_MSG_DHCPDECLINE   4

DECLINE may be sent by client to server to indicate IP already in use.

#define DHCP_MSG_DHCPACK   5

ACK is sent to client by server in confirmation of REQUEST, contains config and IP.

#define DHCP_MSG_DHCPNAK   6

NAK is sent to client by server to indicate problem with REQUEST.

#define DHCP_MSG_DHCPRELEASE   7

RELEASE is sent by client to server to relinquish DHCP lease on IP address, etc.

#define DHCP_MSG_DHCPINFORM   8

INFORM is sent by client to server to request config info, IP address configured locally.

#define GNUC_PACKED   __attribute__((packed))

DHCP Header.

Functions

void dhcpInit (void)

void dhcpIn (unsigned int len, struct netDhcpHeader *packet)

void dhcpRequest (void)

void dhcpRelease (void)

void dhcpTimer (void)

uint8_t dhcpGetOption (uint8_t *options, uint8_t optcode, uint8_t optlen, void *optvalptr)

uint8_t * dhcpSetOption (uint8_t *options, uint8_t optcode, uint8_t optlen, void *optvalptr)

void dhcpPrintHeader (struct netDhcpHeader *packet)

Variables

netBootpHeader GNUC_PACKED

Bootp Header (DHCP is transported by BOOTP/UDP/IP).

Function Documentation

uint8_t dhcpGetOption ( uint8_t * options,

uint8_t optcode,

uint8_t optlen,

void * optvalptr

)

Get a DHCP option from the option list.
Parameters:

options is a pointer to the options field of a DHCP packet.

optcode is the desired option number to retrieve.

optlen is the maximum data length that should be retrieved (less data will be retrieved if option is shorter).

optvalptr is a pointer to where the option value will be stored.

Returns:
actual length of the option data, as stored in the options list.

Definition at line 212 of file dhcp.c.

void dhcpIn ( unsigned int len,

struct netDhcpHeader * packet

)

Processes incoming DHCP packets from UDP port 68. This function is to be called by the stack when a DHCP packet arrives over the network. The DHCP packet will be parsed, handled, and a response will be generated and sent if needed. When the DHCP process completes, the IP addressing will be automatically updated.
Definition at line 42 of file dhcp.c.

void dhcpInit ( void )

Initialize DHCP system. Prepares DHCP for use and initializes lease time to zero.
Definition at line 30 of file dhcp.c.

void dhcpPrintHeader ( struct netDhcpHeader * packet )

Print diagnotic information about BOOTP/DHCP packet.

void dhcpRelease ( void )

Release DHCP lease and assigned network parameters. This function releases the DHCP assigned address and allows the DHCP server to reallocate it.
Definition at line 158 of file dhcp.c.

void dhcpRequest ( void )

Request DHCP assigned network parameters. This function begins the DHCP process. The remainder of operations are handled in dhcpIn().
Definition at line 123 of file dhcp.c.

uint8_t* dhcpSetOption ( uint8_t * options,

uint8_t optcode,

uint8_t optlen,

void * optvalptr

)

Set a DHCP option in the option list.
Parameters:

options is a pointer to the options field of a DHCP packet.

optcode is the option number to write.

optlen is the data length of the option value.

optvalptr is a pointer to the option data to be read.

Returns:
pointer to write location of the next option.

Definition at line 253 of file dhcp.c.

void dhcpTimer ( void )

Periodic DHCP maintenance. This function is to be called once per second and will expire the DHCP lease.
Definition at line 203 of file dhcp.c.

Generated on Sun Oct 29 03:41:09 2006 for Procyon AVRlib by

1.4.2


Data Structures
struct	netBootpHeader
	Bootp Header (DHCP is transported by BOOTP/UDP/IP). More...
struct	netDhcpHeader
	DHCP Header. More...
Defines
#define	BOOTP_HEADER_LEN 236
	length of BOOTP header not including options
#define	BOOTP_OP_BOOTREQUEST 1
	BOOTP Request operation (message from client to server).
#define	BOOTP_OP_BOOTREPLY 2
	BOOTP Reply operation (message from server to client).
#define	BOOTP_HTYPE_ETHERNET 1
#define	BOOTP_HLEN_ETHERNET 6
#define	DHCP_HEADER_LEN 240
	length of DHCP header not including options
#define	DHCP_UDP_SERVER_PORT 67
	UDP port where DHCP requests should be sent.
#define	DHCP_UDP_CLIENT_PORT 68
	UDP port clients will receive DHCP replies.
#define	DHCP_OPT_PAD 0
	token padding value (make be skipped)
#define	DHCP_OPT_NETMASK 1
	subnet mask client should use (4 byte mask)
#define	DHCP_OPT_ROUTERS 3
	routers client should use (IP addr list)
#define	DHCP_OPT_TIMESERVERS 4
	time servers client should use (IP addr list)
#define	DHCP_OPT_NAMESERVERS 5
	name servers client should use (IP addr list)
#define	DHCP_OPT_DNSSERVERS 6
	DNS servers client should use (IP addr list).
#define	DHCP_OPT_HOSTNAME 12
	host name client should use (string)
#define	DHCP_OPT_DOMAINNAME 15
	domain name client should use (string)
#define	DHCP_OPT_REQUESTEDIP 50
	IP address requested by client (IP address).
#define	DHCP_OPT_LEASETIME 51
	DHCP Lease Time (uint32 seconds).
#define	DHCP_OPT_DHCPMSGTYPE 53
	DHCP message type (1 byte).
#define	DHCP_OPT_SERVERID 54
	Server Identifier (IP address).
#define	DHCP_OPT_PARAMREQLIST 55
	Paramerter Request List (n OPT codes).
#define	DHCP_OPT_RENEWALTIME 58
	DHCP Lease Renewal Time (uint32 seconds).
#define	DHCP_OPT_REBINDTIME 59
	DHCP Lease Rebinding Time (uint32 seconds).
#define	DHCP_OPT_END 255
	token end value (marks end of options list)
#define	DHCP_MSG_DHCPDISCOVER 1
	DISCOVER is broadcast by client to solicit OFFER from any/all DHCP servers.
#define	DHCP_MSG_DHCPOFFER 2
	OFFER(s) are made to client by server to offer IP address and config info.
#define	DHCP_MSG_DHCPREQUEST 3
	REQUEST is made my client in response to best/favorite OFFER message.
#define	DHCP_MSG_DHCPDECLINE 4
	DECLINE may be sent by client to server to indicate IP already in use.
#define	DHCP_MSG_DHCPACK 5
	ACK is sent to client by server in confirmation of REQUEST, contains config and IP.
#define	DHCP_MSG_DHCPNAK 6
	NAK is sent to client by server to indicate problem with REQUEST.
#define	DHCP_MSG_DHCPRELEASE 7
	RELEASE is sent by client to server to relinquish DHCP lease on IP address, etc.
#define	DHCP_MSG_DHCPINFORM 8
	INFORM is sent by client to server to request config info, IP address configured locally.
#define	GNUC_PACKED __attribute__((packed))
	DHCP Header.
Functions
void	dhcpInit (void)
void	dhcpIn (unsigned int len, struct netDhcpHeader *packet)
void	dhcpRequest (void)
void	dhcpRelease (void)
void	dhcpTimer (void)
uint8_t	dhcpGetOption (uint8_t options, uint8_t optcode, uint8_t optlen, void optvalptr)
uint8_t *	dhcpSetOption (uint8_t options, uint8_t optcode, uint8_t optlen, void optvalptr)
void	dhcpPrintHeader (struct netDhcpHeader *packet)
Variables
netBootpHeader	GNUC_PACKED
	Bootp Header (DHCP is transported by BOOTP/UDP/IP).

DHCP Protocol Library (dhcp.c) [Network Library]

Detailed Description

Data Structures

Defines

Functions

Variables

Function Documentation

DHCP Protocol Library (dhcp.c)
[Network Library]