dhcp.h

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#ifndef CONFIG_DHCP_H
#define CONFIG_DHCP_H

/** @file
 *
 * DHCP configuration
 *
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <config/defaults.h>

/*
 * DHCP and PXE Boot Server timeout parameters
 *
 * Initial and final timeout for DHCP discovery
 *
 * The PXE spec indicates discover request are sent 4 times, with
 * timeouts of 4, 8, 16, 32 seconds.  iPXE by default uses 1, 2, 4, 8.
 */
#define DHCP_DISC_START_TIMEOUT_SEC     1
#define DHCP_DISC_END_TIMEOUT_SEC       10
//#define DHCP_DISC_START_TIMEOUT_SEC   4       /* as per PXE spec */
//#define DHCP_DISC_END_TIMEOUT_SEC     32      /* as per PXE spec */

/*
 * Maximum number of discovery deferrals due to blocked links
 * (e.g. from non-forwarding STP ports)
 */
#define DHCP_DISC_MAX_DEFERRALS         60

/*
 * ProxyDHCP offers are given precedence by continue to wait for them
 * after a valid DHCPOFFER is received.  We'll wait through this
 * timeout for it.  The PXE spec indicates waiting through the 4 & 8
 * second timeouts, iPXE by default stops after 2.
 */
#define DHCP_DISC_PROXY_TIMEOUT_SEC     2
//#define DHCP_DISC_PROXY_TIMEOUT_SEC   11      /* as per PXE spec */

/*
 * Per the PXE spec, requests are also tried 4 times, but at timeout
 * intervals of 1, 2, 3, 4 seconds.  To adapt this to an exponential
 * backoff timer, we can either do 1, 2, 4, 8, ie. 4 retires with a
 * longer interval or start at 0 (0.25s) for 0.25, 0.5, 1, 2, 4,
 * ie. one extra try and shorter initial timeouts.  iPXE by default
 * does a combination of both, starting at 0 and going through the 8
 * second timeout.
 */
#define DHCP_REQ_START_TIMEOUT_SEC      0
#define DHCP_REQ_END_TIMEOUT_SEC        10
//#define DHCP_REQ_END_TIMEOUT_SEC      4       /* as per PXE spec */

/*
 * A ProxyDHCP offer without PXE options also goes through a request
 * phase using these same parameters, but note the early break below.
 */
#define DHCP_PROXY_START_TIMEOUT_SEC    0
#define DHCP_PROXY_END_TIMEOUT_SEC      10
//#define DHCP_PROXY_END_TIMEOUT_SEC    8       /* as per PXE spec */

/*
 * A ProxyDHCP request timeout should not induce a failure condition,
 * so we always want to break before the above set of timers expire.
 * The iPXE default value of 2 breaks at the first timeout after 2
 * seconds, which will be after the 2 second timeout.
 */
#define DHCP_REQ_PROXY_TIMEOUT_SEC      2
//#define DHCP_REQ_PROXY_TIMEOUT_SEC    7       /* as per PXE spec */

/*
 * Per the PXE spec, a PXE boot server request is also be retried 4
 * times at timeouts of 1, 2, 3, 4.  iPXE uses the same timeouts as
 * discovery, 1, 2, 4, 8, but will move on to the next server if
 * available after an elapsed time greater than 3 seconds, therefore
 * effectively only sending 3 tries at timeouts of 1, 2, 4.
 */
#define PXEBS_START_TIMEOUT_SEC         1
#define PXEBS_END_TIMEOUT_SEC           10
//#define PXEBS_START_TIMEOUT_SEC       0       /* as per PXE spec */
//#define PXEBS_END_TIMEOUT_SEC         8       /* as per PXE spec */

/*
 * Increment to the next PXE Boot server, if available, after this
 * this much time has elapsed.
 */
#define PXEBS_MAX_TIMEOUT_SEC           3
//#define PXEBS_MAX_TIMEOUT_SEC         7       /* as per PXE spec */

#include <config/local/dhcp.h>

#endif /* CONFIG_DHCP_H */