Re: Grub Not Routing TFTP Appropriately

[Andrei Borzenkov]

16.05.2017 22:49, Travis DePrato пишет:
> Yes - I just built grub-2.02 from ftp://ftp.gnu.org/gnu/grub/ and can
> confirm that it's doing the same thing (sending packets to the wrong
> ethernet address).
> 
> I'm not sure what you mean by a packet trace from the port grub is
> connected to. I've placed wireshark between the client and the wall. The
> conversation looks roughly like this:

Please provide raw packet trace.

> 
> DHCP DISCOVER/REQUEST/ACKNOWLEDGE
> Client ARP's for TFTP server
> Client sends TFTP RRQ for pxe/grub/x86_64-efi/core.efi (to router's mac
> address and TFTP server's IP address)
> [ Lots of Blocks Transferred ]
> Client ARP's for router
> Client sends TFTP RRQ for pxe/grub/x86_64-efi/normal.mod (to router's mac
> address and TFTP server's IP address)
> TFTP server doesn't get it, client continues trying to send RRQ for
> normal.mod
> 
> On Tue, May 16, 2017 at 12:49 PM Andrei Borzenkov <address@hidden>
> wrote:
> 
>> 16.05.2017 18:23, Travis DePrato пишет:
>>> grub2-efi-2.02-0.29, taken from RHEL 7.2 installation media rpm.
>>>
>>
>> Can you reproduce it with plain upstream version? It is hard to tell
>> what upstream it corresponds exactly.
>>
>> There was similar bug that was fixed relatively long ago. If you can
>> reproduce it with upstream, could you provide packet trace, if possible
>> from the port grub is connected to?
>>
>>> On Mon, May 15, 2017 at 11:17 PM Andrei Borzenkov <address@hidden>
>>> wrote:
>>>
>>>> 15.05.2017 22:37, Travis DePrato пишет:
>>>>> Hello, all!
>>>>>
>>>>> I've been attempting to get UEFI Network booting working for a while
>> now
>>>>> (compounded by many unrelated issues) but I've run into one that I
>>>> believe
>>>>> to be definitely the fault of GRUB (perhaps this should be a bug
>> report?
>>>>> I'm not sure).
>>>>>
>>>>> I've been using various grubx64.efi/bootx64.efi/core.efi images. Each
>>>>> machine seems to have the same issue: the uefi network rom loads the
>> grub
>>>>> efi image appropriately, then when it tries to load grub.cfg (for
>>>>> grubx64.efi) or the other components (starting with normal.mod), it
>>>> routes
>>>>> the packets incorrectly.
>>>>>
>>>>> For the initial .efi image, it communicates directly with the TFTP
>> server
>>>>> on the ethernet layer (i.e. packets are routed directly to the mac
>>>> address
>>>>> of the TFTP server) whereas when grub continues trying to load
>>>> components,
>>>>> it tries to route through the router/gateway (it first arp's for the IP
>>>> of
>>>>> the gateway sends packets to the ethernet address of the gateway), and
>>>>> those packets are summarily dropped (I've confirmed that the TFTP
>> server
>>>>> doesn't get them via wireshark).
>>>>>
>>>>> Ideas?
>>>>>
>>>>
>>>> What is your grub version?
>>>>
>>
>> --
> Travis DePrato (he/him/his)
> University of Michigan, Ann Arbor
> Computer Science & Engineering
> Mathematics (Discrete and Algorithmic Methods)
> Computer Consultant at EECS DCO
>