Re: [lwip-users] A problem in DHCP, and a potential fix

[Michael Figg]

Simon,

I created myself a savannah login and started to enter a new bug, but
when I got to the bottom of the bug submission page, I saw the line
that told me to check whether a bug had already been submitted.  It
had.

I found bug # 25576, and corresponding patch # 6721.  I also looked at
the patch changes, and the only problem I have with these changes is
that the changes in the patch don't ensure that the source address of
the dhcp discover and request packets aren't guaranteed to be zero.
Every packet trace I have ever seen of dhcp discover and request
packets have the source address set to zero.

Additionally, if DHCP_DOES_ARP_CHECK is true, and dhcp_check is
called, I don't see anything in the code to ensure that the gratuitous
arp done by arp_check sets the tell address to the offered_ip_address.

So, since I don't know much about the lwip change process, I don't
know if these questions of mine are important.  Regardless, I have a
fix for my problem which works in my context.

Good luck,
Mike

On Wed, Jul 8, 2009 at 9:38 AM, address@hidden<address@hidden> wrote:
> Michael Figg wrote:
>>
>> Greetings,
>>
>> I have been using lwip to do dhcp client requests, and have found a
>> problem with the current lwip code.  In particular, it is possible to
>> send DHCP discover requests with the source ip address NOT set to
>> 0.0.0.0.  I have discovered that doing this causes incompatibility
>> problems with some linksys routers.
>>
>> I have coded a fix that seems to work.  I would like to show this fix
>> to someone in case they want to fold it back into the lwip source
>> tree.  How do I do this?
>>
>
> Normally, stuff like this is best discussed on the other mailing list,
> lwip-devel. If it's a bug, then please add an entry in the bugtracker at
> http://savannah.nongnu.org/bugs/?group=lwip if you have a patch ready,
> please create a patch entry instead and attach the patch (as unified diff so
> we can easily apply it): http://savannah.nongnu.org/patch/?group=lwip
>
> For both the bug tracker and patch management, you need to create an account
> at savannah.
>
> Simon
>
>
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