src/config/dhcp.h

   1 #ifndef CONFIG_DHCP_H
   2 #define CONFIG_DHCP_H
   3
   4 /** @file
   5  *
   6  * DHCP configuration
   7  *
   8  */
   9
  10 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  11
  12 #include <config/defaults.h>
  13
  14 /*
  15  * DHCP and PXE Boot Server timeout parameters
  16  *
  17  * Initial and final timeout for DHCP discovery
  18  *
  19  * The PXE spec indicates discover request are sent 4 times, with
  20  * timeouts of 4, 8, 16, 32 seconds.  iPXE by default uses 1, 2, 4, 8.
  21  */
  22 #define DHCP_DISC_START_TIMEOUT_SEC     1
  23 #define DHCP_DISC_END_TIMEOUT_SEC       10
  24 //#define DHCP_DISC_START_TIMEOUT_SEC   4       /* as per PXE spec */
  25 //#define DHCP_DISC_END_TIMEOUT_SEC     32      /* as per PXE spec */
  26
  27 /*
  28  * Maximum number of discovery deferrals due to blocked links
  29  * (e.g. from non-forwarding STP ports)
  30  */
  31 #define DHCP_DISC_MAX_DEFERRALS         180
  32
  33 /*
  34  * ProxyDHCP offers are given precedence by continue to wait for them
  35  * after a valid DHCPOFFER is received.  We'll wait through this
  36  * timeout for it.  The PXE spec indicates waiting through the 4 & 8
  37  * second timeouts, iPXE by default stops after 2.
  38  */
  39 #define DHCP_DISC_PROXY_TIMEOUT_SEC     2
  40 //#define DHCP_DISC_PROXY_TIMEOUT_SEC   11      /* as per PXE spec */
  41
  42 /*
  43  * Per the PXE spec, requests are also tried 4 times, but at timeout
  44  * intervals of 1, 2, 3, 4 seconds.  To adapt this to an exponential
  45  * backoff timer, we can either do 1, 2, 4, 8, ie. 4 retires with a
  46  * longer interval or start at 0 (0.25s) for 0.25, 0.5, 1, 2, 4,
  47  * ie. one extra try and shorter initial timeouts.  iPXE by default
  48  * does a combination of both, starting at 0 and going through the 8
  49  * second timeout.
  50  */
  51 #define DHCP_REQ_START_TIMEOUT_SEC      0
  52 #define DHCP_REQ_END_TIMEOUT_SEC        10
  53 //#define DHCP_REQ_END_TIMEOUT_SEC      4       /* as per PXE spec */
  54
  55 /*
  56  * A ProxyDHCP offer without PXE options also goes through a request
  57  * phase using these same parameters, but note the early break below.
  58  */
  59 #define DHCP_PROXY_START_TIMEOUT_SEC    0
  60 #define DHCP_PROXY_END_TIMEOUT_SEC      10
  61 //#define DHCP_PROXY_END_TIMEOUT_SEC    8       /* as per PXE spec */
  62
  63 /*
  64  * A ProxyDHCP request timeout should not induce a failure condition,
  65  * so we always want to break before the above set of timers expire.
  66  * The iPXE default value of 2 breaks at the first timeout after 2
  67  * seconds, which will be after the 2 second timeout.
  68  */
  69 #define DHCP_REQ_PROXY_TIMEOUT_SEC      2
  70 //#define DHCP_REQ_PROXY_TIMEOUT_SEC    7       /* as per PXE spec */
  71
  72 /*
  73  * Per the PXE spec, a PXE boot server request is also be retried 4
  74  * times at timeouts of 1, 2, 3, 4.  iPXE uses the same timeouts as
  75  * discovery, 1, 2, 4, 8, but will move on to the next server if
  76  * available after an elapsed time greater than 3 seconds, therefore
  77  * effectively only sending 3 tries at timeouts of 1, 2, 4.
  78  */
  79 #define PXEBS_START_TIMEOUT_SEC         1
  80 #define PXEBS_END_TIMEOUT_SEC           10
  81 //#define PXEBS_START_TIMEOUT_SEC       0       /* as per PXE spec */
  82 //#define PXEBS_END_TIMEOUT_SEC         8       /* as per PXE spec */
  83
  84 /*
  85  * Increment to the next PXE Boot server, if available, after this
  86  * this much time has elapsed.
  87  */
  88 #define PXEBS_MAX_TIMEOUT_SEC           3
  89 //#define PXEBS_MAX_TIMEOUT_SEC         7       /* as per PXE spec */
  90
  91 #include <config/local/dhcp.h>
  92
  93 #endif /* CONFIG_DHCP_H */