DOS clients slow on Samba 4.1.7+ (bug 10422)

[Dominic Raferd]

On 10/10/2014 15:47, Volker Lendecke wrote:
> On Fri, Oct 10, 2014 at 04:06:07PM +0200, Volker Lendecke wrote:
>> On Fri, Oct 10, 2014 at 02:41:52PM +0100, Dominic Raferd wrote:
>>> Yes I think I can do that with tcpdump, do I just zip it up and post
>>> it here?
>> Sure. If you think it's too large, send it to me directly.
> So you depend on the "read raw"? Without that your client is
> unusably slow?
>
> Volker
>

Now I look at the trace in Wireshark I begin to understand what you 
mean. I attach the first 200 packets of the original trace and also the 
first 200 packets of an identical series of actions initiated from the 
same client machine but to a server running samba 4.1.5 instead of 
4.1.12. Looking at the full packet trace (not attached) shows that the 
complete sequence took 13.3 seconds with 4.1.5 but took 49.4 seconds 
with 4.1.12. The time does not just depend on the network communication, 
but this is the only factor that has changed between the two traces.

You are the expert, but from what I can see the problem starts at line 
128/129 (129/130 for 4.1.5). At line 128 the client requests a read of 
1024 bytes, but Samba responds (line 129) with 972 bytes, whereas Samba 
4.1.5 responds with 1024 bytes. In both cases the client then switches 
to 'read raw', so this behaviour seems to be normal.

Dominic
-- 
*TimeDicer* <http://www.timedicer.co.uk>: Free File Recovery from Whenever
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