[CentOS] traffic distribution not happening in centos 6.5

Varun Sharma

vsdssd at gmail.com
Mon Jun 2 09:15:01 UTC 2014


Hi,

No, source IP address differ in packets.Even I change source port also
in packets.

Regards
Varun

On Tue, May 27, 2014 at 11:54 PM, Marcelo Ricardo Leitner
<marcelo.leitner at gmail.com> wrote:
> Em 25-05-2014 07:35, Varun Sharma escreveu:
>> Hi,
>>
>> I am experimenting with libnetfilter_queue. libnetfilter_queue is a
>> userspace library providing an API to packets that have been queued by
>> the kernel packet filter.
>>
>> I am using sample code(nfqnl_test.c) available on netfilter.org. I
>> have generated two binaries (queue0 and queue1) using that
>> nfqnl_test.c sample code.
>>
>> These binaries are working as per expected behaviour in case of Centos
>> 6.2 but with Centos 6.5 only one queue is receiving network traffic.
>>
>> I am not able to understand why only one queue is receiving network
>> traffic in case of Centos 6.5 whereas same network traffic is being
>> distributed in both the queues with Centos 6.2.
>>
>> uname –a :-
>>
>> Linux hwcentos8 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC
>> 2013 x86_64 x86_64 x86_64 GNU/Linux
>>
>> Machine Info:
>>
>> 16 core machine with 64GB RAM.
>>
>> Command used for iptables in Centos 6.5 :-
>>
>> iptables -A INPUT -j NFQUEUE --queue-balance 0:1
>>
>>
>> Output In Centos 6.5 :-
>>
>>
>> [varun at exp2 ~]$ ./queue0
>>
>> opening library handle
>>
>> unbinding existing nf_queue handler for AF_INET (if any)
>>
>> binding nfnetlink_queue as nf_queue handler for AF_INET
>>
>> binding this socket to queue '0'
>>
>> setting copy_packet mode
>>
>> pkt received
>>
>> queue0 hw_protocol=0x0800 hook=1 id=0 hw_src_addr=fc:4d:d4:d3:7f:73
>> indev=2 payload_len=40
>>
>> entering callback
>>
>> pkt received
>>
>> queue0 hw_protocol=0x0800 hook=1 id=1 hw_src_addr=fc:4d:d4:d3:7f:73
>> indev=2 payload_len=40
>>
>> entering callback
>>
>> pkt received
>>
>> queue0 hw_protocol=0x0800 hook=1 id=2 hw_src_addr=fc:4d:d4:d3:7f:73
>> indev=2 payload_len=40
>>
>> entering callback
>>
>> pkt received
>>
>> queue0 hw_protocol=0x0800 hook=1 id=3 hw_src_addr=fc:4d:d4:f1:e1:5f
>> indev=2 payload_len=78
>>
>> entering callback
>>
>>
>>
>> [varun at exp2 ~]$ ./queue1
>>
>> opening library handle
>>
>> unbinding existing nf_queue handler for AF_INET (if any)
>>
>> binding nfnetlink_queue as nf_queue handler for AF_INET
>>
>> binding this socket to queue '1'
>>
>> setting copy_packet mode
>>
>>
>>
>>
>> Please let me know if more information is required.
>
> Hi,
>
> Considering the MAC address is the same, should I assume both IP
> addresses are the same too? Because it balances according to the hash of
> src ip, dst ip and ip proto (tcp, udp..).
>
> That is, all packets from a single tcp stream will always go through the
> same queue, avoiding re-ordering.
>
> Cheers,
> Marcelo
>
>
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