Nut/OS API

 *
 * $Log: dhcpc.c,v $
 * Revision 1.22  2006/08/01 07:38:41  haraldkipp
 * DHCP client failed because of alignment errors. Removed the dispensable
 * 'packed' attribute from the dyn_cfg structure.
 *
 * Revision 1.21  2006/01/23 19:52:10  haraldkipp
 * Added required typecasts before left shift.
 *
 * Revision 1.20  2006/01/23 17:35:54  haraldkipp
 * BOOTP and DYNCFG structures must be packed.
 * Fixed memory alignment bug, which retrieved wrong values from DHCP options.
 *
 * Revision 1.19  2005/08/02 17:47:04  haraldkipp
 * Major API documentation update.
 *
 * Revision 1.18  2005/04/05 17:44:57  haraldkipp
 * Made stack space configurable.
 *
 * Revision 1.17  2005/03/28 18:26:59  mrjones4u
 * Fixed non-release bug in DCHP client
 *
 * Revision 1.16  2005/02/03 14:33:56  haraldkipp
 * Several bug fixes and enhancements. The most important fix will
 * avoid hanging, when Ethernut is reset while ICMP pings are
 * received. A large number of changes make the client to follow
 * RFC 2131 more closely, like maintaining renewal and rebind time.
 * Two new API calls, NutDhcpStatus() and NutDhcpError(), allow
 * to query the current status of the DHCP client. The previously
 * introduced API call NutDhcpIsConfigured() has been marked
 * deprecated. Another problem was with timeout, because the client
 * continued negotiation with the server after the timeout time
 * given in the API called elapsed. Now all internal timeouts are
 * adjusted to the API timeout. Furthermore the previous version
 * let the client continue on fatal errors like UDP receive or UDP
 * broadcast failures. Now the client stops on such errors and
 * informs the caller. Finally the documentation has been enhanced.
 *
 * Revision 1.15  2004/12/31 10:51:40  drsung
 * Bugfixes from Michel Hendriks applied:
 * Allocate empty dyncfg's to prevent freeing twice of domain/hostname
 * Clear pointer after ReleaseDynCfg to prevent freeing twice
 * Make sure SelectOffer is never called with 0 offers
 * When falling back from rebooting to selecting, clear
 * the received ip address so NutDhcpIfConfig does not
 * assume it has been configured properly
 *
 * Revision 1.14  2004/04/15 07:16:47  drsung
 * Now it works... :-/
 *
 * Revision 1.13  2004/04/15 07:11:50  drsung
 * Added hostname support to NutDHCPDiscover
 *
 * Revision 1.12  2004/03/18 11:24:01  haraldkipp
 * Deprecated functions removed
 *
 * Revision 1.11  2004/03/03 17:53:28  drsung
 * Support for new field 'hostname' in structure confos added.
 *
 * Revision 1.10  2004/02/25 16:34:32  haraldkipp
 * New API added to relinguish the DHCP lease. Collecting more
 * than one offer is now disabled, if the application sets timeout
 * below three times of MAX_DHCP_WAIT (5 seconds). The lease renewal
 * will now start when 3/4 has elapsed, opposed to 1/2 used previously.
 * Finally the DHCP thread will sleep as long as possible, while the
 * previous version woke up every ten seconds.
 *
 * Revision 1.9  2004/02/02 18:54:43  drsung
 * gateway ip address was not set, if static network configuration from EEPROM is used.
 *
 * Revision 1.8  2004/01/14 17:50:41  drsung
 * Fix for Win2k DHCP server applied. Thanks to Damian Slee
 *
 * Revision 1.7  2003/11/03 16:22:59  haraldkipp
 * Renewal disabled if lease time is set to zero
 *
 * Revision 1.6  2003/10/13 10:18:08  haraldkipp
 * Using new seconds counter
 *
 * Revision 1.5  2003/08/07 09:09:08  haraldkipp
 * Redesign to follow RFC 2131 more closely.
 *
 * Revision 1.4  2003/07/20 18:25:40  haraldkipp
 * Support secondary DNS.
 *
 * Revision 1.3  2003/07/17 09:44:14  haraldkipp
 * Removed default MAC address and let the caller have a second chance.
 *
 * Revision 1.2  2003/05/15 14:25:38  haraldkipp
 * Some DHCP servers discard discover telegrams.
 * Thanks to Tomohiro Haraikawa.
 *
 * Revision 1.1.1.1  2003/05/09 14:41:57  haraldkipp
 * Initial using 3.2.1
 *
 *


DHCP Client Configuration
The Nut/OS Configurator may be used to override the default values.
#define	DHCP_SERVERPORT 67
	UDP port of DHCP server.
#define	DHCP_CLIENTPORT 68
	UDP port of DHCP client.
#define	MAX_DHCP_MSGSIZE 576
	Maximum DHCP message size we can accept.
#define	MIN_DHCP_MSGSIZE 300
	Minimum DHCP message length.
#define	MAX_DHCP_BUFSIZE 1728
	Maximum UDP buffer size used by the DHCP client.
#define	MIN_DHCP_WAIT 4000
	Minimum number of milliseconds to wait for a response.
#define	MAX_DHCP_WAIT 64000
	Maximum number of milliseconds to wait for a response.
#define	MAX_DCHP_RETRIES 3
	Maximum number of request retries.
#define	MAX_DCHP_RELEASE_RETRIES 0
	Maximum number of release retries.
#define	DHCP_DEFAULT_LEASE 43200
	Default lease time in seconds.
#define	MAX_DHCP_NAPTIME 4294967
	Maximum sleep time in seconds.
#define	NUT_THREAD_DHCPSTACK 512
	Stack size of the DHCP client thread.
DHCP Message Types
See RFC 2131.
#define	DHCP_DISCOVER 1
	Client broadcast to locate available servers.
#define	DHCP_OFFER 2
	Server to client in response to DHCP_DISCOVER.
#define	DHCP_REQUEST 3
	Client message to servers.
#define	DHCP_DECLINE 4
	Client to server indicating network address is already in use.
#define	DHCP_ACK 5
	Server to client with configuration parameters.
#define	DHCP_NAK 6
	Server to client indicating client's notion of network address is incorrect.
#define	DHCP_RELEASE 7
	Client to server relinquishing network address and cancelling remaining lease.
#define	DHCP_INFORM 8
	Client to server, asking only for local configuration parameters.
DHCP Options
Nut/Net recognizes a subset of options defined in RFC 2132.
#define	DHCPOPT_PAD 0
	DHCP pad option.
#define	DHCPOPT_NETMASK 1
	DHCP subnet mask option.
#define	DHCPOPT_GATEWAY 3
	DHCP router option.
#define	DHCPOPT_DNS 6
	DHCP domain name server option.
#define	DHCPOPT_HOSTNAME 12
	DHCP host name option.
#define	DHCPOPT_DOMAIN 15
	DHCP domain name option.
#define	DHCPOPT_BROADCAST 28
	DHCP broadcast address option.
#define	DHCPOPT_REQESTIP 50
	DHCP requested IP address option.
#define	DHCPOPT_LEASETIME 51
	DHCP IP address lease time option.
#define	DHCPOPT_MSGTYPE 53
	DHCP message type option.
#define	DHCPOPT_SID 54
	DHCP server identifier option.
#define	DHCPOPT_PARAMREQUEST 55
	DHCP parameter request list option.
#define	DHCPOPT_MAXMSGSIZE 57
	Maximum DHCP message size option.
#define	DHCPOPT_RENEWALTIME 58
	DHCP renewal time option.
#define	DHCPOPT_REBINDTIME 59
	DHCP rebinding time option.
#define	DHCPOPT_END 255
	DHCP end option.
Typedefs
typedef bootp	BOOTP
	BOOTP message structure type.
typedef dyn_cfg	DYNCFG
	Dynamic configuration structure type.
Functions
void	NutDhcpClient (void *arg)
	DHCP client thread.
int	NutDhcpIfConfig (CONST char name, u_char mac, u_long timeout)
	Automatically configure an Ethernet network interface.
int	NutDhcpRelease (CONST char *name, u_long timeout)
	Relinguish our DHCP lease.
int	NutDhcpInform (CONST char *name, u_long timeout)
	Inform DHCP about an allocated address.
int	NutDhcpStatus (CONST char *name)
	Return DHCP client status.
int	NutDhcpError (CONST char *name)
	Return DHCP error code.
int	NutDhcpIsConfigured (void)
	Check if DHCP has configured our interface.

dhcpc.c File Reference

Detailed Description

DHCP Client Configuration

DHCP Message Types

DHCP Options

Typedefs

Functions