[Winpcap-users] Slow sending?

[Gianluca Varenni]

----- Original Message ----- 
From: <accounts at sandmik.net>
To: <winpcap-users at winpcap.org>
Sent: Friday, March 31, 2006 12:19 AM
Subject: Re: [Winpcap-users] Slow sending?


> Hey guys, thanks a lot for everybody that helped.
>
> pcap_setmintocopy did the trick.
> From 2 seconds ping time, down to < 10 msec.
>
> They should mention it in the manual in the section of sending packets and 
> not just in the exported function section.

mintocopy does *not* affect sending packets at all.

As Loris pointed out in the other mail, mintocopy affect reception, only.

Have a nice day
GV



>
> Thanks.
>
> New accounts at sandmik.net wrote:
>
>> Oh one more thing,
>>
>>    I am sure about the results as I am testing it by pinging two machines 
>> (that are arp poisoned) on the network.
>>
>> The ping is taking around 2 seconds, after some debugging and testing 
>> with ethereal, I found out that each one send there is a delay of around 
>> 1 second, hence the 2 seconds in the ping.
>>
>>    Thank you again.
>>
>> Loris Degioanni wrote:
>>
>>> As far as I know, libdnet and most of the other traffic injection 
>>> libraries end up using WinPcap for actual transmission, so switching to 
>>> them is not going to help a lot.
>>>
>>> First of all, a delay of 1 second seems quite huge, even if a system 
>>> call per packet is issued. Are you sure the delay is in transmission and 
>>> not in reception?
>>> A Rx 1 sec delay is normal if you don't set a low timeout and mintocopy.
>>>
>>> Second: I know of several winpcap-based arp poisoners, and they appear 
>>> to work pretty well. You may want to look at their sources to learn how 
>>> they achieve that. For example, look at http://ettercap.sourceforge.net 
>>> for a very well known one. You'll find more of them at 
>>> http://www.winpcap.org/misc/links.htm#tools.
>>>
>>> Loris
>>>
>>>
>>> New accounts at sandmik.net wrote:
>>>
>>>> Thank you loris for trying to help me.
>>>>
>>>> I have used the queue version as well but I did not get higher 
>>>> performance, I believe because everytime I call this function I only 
>>>> have one packet to send. My ARP Poisoner has to relay packets as soon 
>>>> as they come... So I have this incredible delay.
>>>>
>>>> I think I will be looking into other means (maybe other libraries) of 
>>>> sending the packets (like libdnet, just found it on the web).
>>>>
>>>> If you have used any other mean to send ethernet packets, I would 
>>>> appreciate the help.
>>>>
>>>> Thanks again.
>>>>
>>>> Loris Degioanni wrote:
>>>>
>>>>> If you want to increase the Tx performance, use buffered send 
>>>>> functions(pcap_sendqueue*). pcap_sendpacket() does a context switch 
>>>>> per packet, that's the reason why it's so slow.
>>>>>
>>>>> Loris
>>>>>
>>>>>
>>>>> Accounts wrote:
>>>>>
>>>>>> Hi Everybody.
>>>>>>
>>>>>>    I am using WinPCap to do active redirection of packets. Everything
>>>>>> is working very well except I have one problem.
>>>>>>
>>>>>> WinPCap seems to be very slow to send the packets?
>>>>>>
>>>>>> I checked my code from the time I receive the packet to my code until
>>>>>> the time I call pcap_sendpacket, there is less than 1 ms so I know 
>>>>>> the
>>>>>> problem
>>>>>> is not a bottleneck in my code. However looking at ethereal and doing
>>>>>> some pinging tests. It looks like after I call pcap_sendpacket it is
>>>>>> taking up to 1 second to actually go out.
>>>>>>
>>>>>>    Any ideas?!
>>>>>>
>>>>>>    Any help would be appreciated.
>>>>>>
>>>>>>    And also I tried to use send queues but the same problem.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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>>>>>
>>>>
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>>
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