udhcpc: option -x OPT:VAL clarification
Abdoulaye Walsimou GAYE
awg at embtoolkit.org
Mon Dec 6 22:11:24 UTC 2010
On 12/05/2010 11:22 PM, Denys Vlasenko wrote:
> On Sunday 05 December 2010 20:05, Abdoulaye Walsimou GAYE wrote:
>
>> Can someone clarify usage of -x OPT:VAL please?
>>
> $ udhcpc --help
> BusyBox v1.18.0 (2010-11-23 00:11:12 CET) multi-call binary.
>
> Usage: udhcpc [-fbnqvoCR] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]
> [-H HOSTNAME] [-V VENDOR] [-x OPT:VAL]... [-O OPT]...
> ...
> -x OPT:VAL Include option OPT in sent packets (cumulative)
> Examples of string, numeric, and hex byte opts:
> -x hostname:bbox - option 12
> -x lease:3600 - option 51 (lease time)
> -x 0x3d:0100BEEFC0FFEE - option 61 (client id)
>
>
> Is this text unclear?
> Please provide question(s) it doesn't answer.
I am using busybox-1.17.4 and the help is not displayed like this.
Thanks for clarification.
> Well, the picture seems to be garbled. "option-data1" looks strange.
> Ypou meant:
>
> The format of the V-I Vendor Class option is as follows:
>
> 1 1 1 1 1 1
> 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> | option-code | option-len |
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> | enterprise-number1 |
> | |
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> | data-len1 | |
> +-+-+-+-+-+-+-+-+ |
> / vendor-class-data1 /
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ----
> | enterprise-number2 | ^
> | | |
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> | data-len2 | | optional
> +-+-+-+-+-+-+-+-+ | |
> / vendor-class-data2 / |
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
> ~ ... ~ V
> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ----
>
>
> Since enterprise-number1, data-len1, vendor-class-data1
> are likely to be nonrepresentable as strings,
> encode them as hex bytes:
>
> -x 125:010203040506070809
>
> replace 01 with the value of 1st byte, 02 with with the value
> of 2nd one and so on.
>
>
Indeed this is tedious but it works.
Thanks,
AWG
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