iPXE
dhcp.h
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00001 #ifndef CONFIG_DHCP_H
00002 #define CONFIG_DHCP_H
00003 
00004 /** @file
00005  *
00006  * DHCP configuration
00007  *
00008  */
00009 
00010 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
00011 
00012 #include <config/defaults.h>
00013 
00014 /*
00015  * DHCP and PXE Boot Server timeout parameters
00016  *
00017  * Initial and final timeout for DHCP discovery
00018  *
00019  * The PXE spec indicates discover request are sent 4 times, with
00020  * timeouts of 4, 8, 16, 32 seconds.  iPXE by default uses 1, 2, 4, 8.
00021  */
00022 #define DHCP_DISC_START_TIMEOUT_SEC     1
00023 #define DHCP_DISC_END_TIMEOUT_SEC       10
00024 //#define DHCP_DISC_START_TIMEOUT_SEC   4       /* as per PXE spec */
00025 //#define DHCP_DISC_END_TIMEOUT_SEC     32      /* as per PXE spec */
00026 
00027 /*
00028  * Maximum number of discovery deferrals due to blocked links
00029  * (e.g. from non-forwarding STP ports)
00030  */
00031 #define DHCP_DISC_MAX_DEFERRALS         60
00032 
00033 /*
00034  * ProxyDHCP offers are given precedence by continue to wait for them
00035  * after a valid DHCPOFFER is received.  We'll wait through this
00036  * timeout for it.  The PXE spec indicates waiting through the 4 & 8
00037  * second timeouts, iPXE by default stops after 2.
00038  */
00039 #define DHCP_DISC_PROXY_TIMEOUT_SEC     2
00040 //#define DHCP_DISC_PROXY_TIMEOUT_SEC   11      /* as per PXE spec */
00041 
00042 /*
00043  * Per the PXE spec, requests are also tried 4 times, but at timeout
00044  * intervals of 1, 2, 3, 4 seconds.  To adapt this to an exponential
00045  * backoff timer, we can either do 1, 2, 4, 8, ie. 4 retires with a
00046  * longer interval or start at 0 (0.25s) for 0.25, 0.5, 1, 2, 4,
00047  * ie. one extra try and shorter initial timeouts.  iPXE by default
00048  * does a combination of both, starting at 0 and going through the 8
00049  * second timeout.
00050  */
00051 #define DHCP_REQ_START_TIMEOUT_SEC      0
00052 #define DHCP_REQ_END_TIMEOUT_SEC        10
00053 //#define DHCP_REQ_END_TIMEOUT_SEC      4       /* as per PXE spec */
00054 
00055 /*
00056  * A ProxyDHCP offer without PXE options also goes through a request
00057  * phase using these same parameters, but note the early break below.
00058  */
00059 #define DHCP_PROXY_START_TIMEOUT_SEC    0
00060 #define DHCP_PROXY_END_TIMEOUT_SEC      10
00061 //#define DHCP_PROXY_END_TIMEOUT_SEC    8       /* as per PXE spec */
00062 
00063 /*
00064  * A ProxyDHCP request timeout should not induce a failure condition,
00065  * so we always want to break before the above set of timers expire.
00066  * The iPXE default value of 2 breaks at the first timeout after 2
00067  * seconds, which will be after the 2 second timeout.
00068  */
00069 #define DHCP_REQ_PROXY_TIMEOUT_SEC      2
00070 //#define DHCP_REQ_PROXY_TIMEOUT_SEC    7       /* as per PXE spec */
00071 
00072 /*
00073  * Per the PXE spec, a PXE boot server request is also be retried 4
00074  * times at timeouts of 1, 2, 3, 4.  iPXE uses the same timeouts as
00075  * discovery, 1, 2, 4, 8, but will move on to the next server if
00076  * available after an elapsed time greater than 3 seconds, therefore
00077  * effectively only sending 3 tries at timeouts of 1, 2, 4.
00078  */
00079 #define PXEBS_START_TIMEOUT_SEC         1
00080 #define PXEBS_END_TIMEOUT_SEC           10
00081 //#define PXEBS_START_TIMEOUT_SEC       0       /* as per PXE spec */
00082 //#define PXEBS_END_TIMEOUT_SEC         8       /* as per PXE spec */
00083 
00084 /*
00085  * Increment to the next PXE Boot server, if available, after this
00086  * this much time has elapsed.
00087  */
00088 #define PXEBS_MAX_TIMEOUT_SEC           3
00089 //#define PXEBS_MAX_TIMEOUT_SEC         7       /* as per PXE spec */
00090 
00091 #include <config/local/dhcp.h>
00092 
00093 #endif /* CONFIG_DHCP_H */