[Dibbler-devel] Prefix delegation & prefix pool management issue.

Tomasz Mrugalski thomson at klub.com.pl
Thu May 3 12:11:11 CEST 2007


On Tue, 1 May 2007 somebody known as Tomasz Mrugalski wrote:
> Anyway, I'll take a closer look at this issue soon (tomorrow? or the day
> after tomorrow).

Hi,
I had some time and I was able to reproduce this bug.

Well, there are several things that went wrong and the result was that the
same prefix has been assigned. Details:

1. The prefix randomisation method is not very good, so it never returns
    last value from the available prefix, and since in this case we have
    only 2 prefixes, always the first is returned (to be exact, th chance
    to return second one by random is 1/2^63).

2. Take a look at this of the AddrMgr.cpp code and try to guess, what is
    wrong :)

bool TAddrMgr::prefixIsFree(SPtr<TIPv6Addr> prefix)
{
     // FIXME: implement this
     return true;
}

In general, dibbler does not handle border cases too well, e.g. when 
the address (or prefix) pool is almost completely used, i.e. there 
is only one prefix or address left to assign.

Anyway, I'm working on both issues. I suppose the fix will be ready today
or tomorrow.

Thanks again for this not-so-obvious bug report

-- 
Tomasz Mrugalski,              | "We all know Linux is great...it does    |
thomson(at)klub(dot)com(dot)pl |  infinite loops in 5 seconds."           |
                                |                           Linus Torvalds |


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