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From: Michael B. <mb...@fe...> - 2002-12-13 02:52:56
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On 12 Dec 2002, Eric W. Biederman wrote: > Currently etherboot does not interpret any encapsulated options > (except in the case of FreeBSD). Not quite sure what you mean here. Etherboot will accept any of the old Etherboot-specific options inside an etherboot-encapsulated-options field (i.e. a dhcp option 150). There is an option #define ALLOW_ONLY_ENCAPSULATED which will cause it to ignore Etherboot-specific options that are *not* in an etherboot-encapsulated-options field. This option is undefined by default in order to preserve backwards compatibility. > When using encapsulated options we are not checking for a magic signature. We still check for the magic signature in option 128. If ALLOW_ONLY_ENCAPSULATED is defined then this option will be accepted only if it is found within etherboot-encapsulated-options. There are two macros defined that are used in main.c to mark whether or not an option should be treated as in the Etherboot encapsulated namespace. If an option is marked is NON_ENCAP_OPT then it will be ignored if found within an etherboot-encapsulated-options field. If an option is marked as ENCAP_OPT then it will be ignored if found outside an etherboot-encapsulated-options field (but only if ALLOW_ONLY_ENCAPSULATED is defined). If an option is not marked as either then it will be accepted anywhere. Option 128 is marked as ENCAP_OPT hence if ALLOW_ONLY_ENCAPSULATED is defined then it is valid only within etherboot-encapsulated-options and hence acts as a magic signature for the etherboot-encapsulated-options field. > With respect to transmitting options I am less certain on how that > should be handled. But my gut impression says vendor encapsulated > options is the way to go. But it has been suggested that dhcpv3 > cannot parse those options. I will at least want to verify that > before I go any further. There is a sample DHCPD config file in contrib/initrd/dhcpd.conf.etherboot.include. If you can achieve what is in there using vendor-encapsulated-options then one of my two objections to using VEO will disappear. Michael Brown http://www.fensystems.co.uk |
