RE: Fwd: Packet Loss (Robert Clove)
Hi Robert, You can write your own kernel (using netfilter framework) module to count the number of packets received at kernel. And, with this kernel module you can have the flexibility of filtering the packets you are sending from packeth. Thanks & Regards Murali --- Date: Sat, 2 Nov 2013 07:28:24 -0700 From: Robert Clove Subject: Fwd: Packet Loss To: kernelnewbies Message-ID: Content-Type: text/plain; charset="iso-8859-1" On Mon, Oct 28, 2013 at 5:44 PM, Kristof Provost wrote: > On 2013-10-28 17:32:43 (+0530), Robert Clove > wrote: > > Kind of Packets :- *UDP* > > How are you generating them? :-* Packeth ( > > http://packeth.sourceforge.net/packeth/Home.html)* > > kernel version : uname -r - *2.6.32-358.18.1.el6.x86_64 > > * > > Are you *SURE* you're sending 1000? - *ya checked through packeth > > status bar and also through ifconfig command* I have connected them > > through LAN cable (cat 6) back to back. > > > > Changed cable but no use. > > What should i do? > > > Break down the problem. Get that smart switch to tell you if the > packets are lost by the sender of the receiver. > > Test if it's bidirectional (i.e. does it still happen if the switch > the sender and receiver)? > > Does it still happen if you send only 100 packets? Do you still lose > 30% then, or do you lose more or less? > > Perhaps try a kernel that isn't nearly five years old too. > > Also, don't top-post. > > Regards, > Kristof > > Hey Sir, I just want to know are there any driver or kernel parameters that we can adjust to get the better packet capture? Thanks -- next part -- An HTML attachment was scrubbed... URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20131102/08d14366/attachment-0001.html ::DISCLAIMER:: The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. E-mail transmission is not guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or may contain viruses in transmission. The e mail and its contents (with or without referred errors) shall therefore not attach any liability on the originator or HCL or its affiliates. Views or opinions, if any, presented in this email are solely those of the author and may not necessarily reflect the views or opinions of HCL or its affiliates. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and / or publication of this message without the prior written consent of authorized representative of HCL is strictly prohibited. If you have received this email in error please delete it and notify the sender immediately. Before opening any email and/or attachments, please check them for viruses and other defects. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
own distribution Centos 6.4
Hi, I am trying to make a distribution for Centos 6.4 . I was gone the steps from this link ( http://smorgasbork.com/component/content/article/35-linux/128-building-a-custom-centos-6-kickstart-disc-part-1) . After installing with minimal distribution machine is gives this error . Kernel Panic - not syncing: Attempted to kill init! Pid: 1 comm: init Not tainted. I have put all the dependencies also . Why this problem comes? can u tell me isit any other way to make the distribution for CentOs 6.4?? Thanks and Reagrds Juliet ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: IPv4 Fragmentation in a IPIP6 tunnel
Hello,
I investigated better the problem, the MTU (WAN and LAN side) is 1500 bytes, I
am running a test which send a packet of 1496 bytes LAN side and is not
fragmented.
The problem appears because the size of the IPv6 header plus the payload (1496
bytes) is greater then the MTU (1500), at that point the IPv4 packet is
fragmented while my expectation is that just the IPv6 should be. I placed a
printk in the ip_fragment function and I can see that the packet is fragmented
over there, my expectation is that piece of code should not been ever executed
since i am sending over IPv6, I would remark that I don't have a fully
understanding of the linux kernel networking stack implementation.
Where should the IPv6 fragmentation be done ?
Pietro Paolini
pulsarpie...@aol.com
-Original Message-
From: Fan Du
To: Pietro Paolini
Cc: kernelnewbies ; p.paolini
Sent: Thu, Oct 31, 2013 10:39 am
Subject: Re: IPv4 Fragmentation in a IPIP6 tunnel
Hi Pietro
On 2013年10月30日 23:02, Pietro Paolini wrote:
> Hello everyone,
> I am working for an embedded Linux firmware running on a CPE and I am
> using an IP4 over IPv6 tunnel configured as following:
>
> ip -f inet6 tunnel add tun1 mode ipip6 remote XX:XX:XX local XX:XX:XX
> dev eth0
>
> And it works fine until I don't try to test the fragment case: I send a
> too big UDP packet and my expectation - and requirement (sob) - would
> be a IPv6 packet fragmentation but what I get is a double
> fragmentation (IPv4 and IPv6), then, summarizing:
>
> IPv4 --> [IPv4-1-segment][IPv6] [IPv4-2-segment][IPv6]
I didn't manage to test this, but a first glance make me think your expectation
has one requirement:
UDP packet + IPv4 header doesn't not exceed mtu of IPv4 src->dst, *AND* UDP
packet + IPv4 header exceed the IPv6 tunnel mtu.
UDP packet first has to fit into IPv4 layer size(phase 1), and then tunneled in
IPv6 style(phase 2). So two kinds of mtu involved here.
> Looking at the kernel code - which in I am not an expert - I observed
> that the function ip_finish_output :
>
> #if defined(CONFIG_NETFILTER)&& defined(CONFIG_XFRM)
> /* Policy lookup after SNAT yielded a new policy */
> if (skb_dst(skb)->xfrm != NULL) {
> IPCB(skb)->flags |= IPSKB_REROUTED;
> return dst_output(skb);
> }
> #endif
> #if defined(CONFIG_INET_IPSEC_OFFLOAD)
> if ((skb->ipsec_offload == 0)&&
> skb->len> ip_skb_dst_mtu(skb)&& !skb_is_gso(skb))
> #else
> if (skb->len> ip_skb_dst_mtu(skb)&& !skb_is_gso(skb))
> #endif
> return ip_fragment(skb, ip_finish_output2);
> else
> return ip_finish_output2(skb);
>
> Does not care about it, it just fragments if the MTU does not match.
>
> Is there any options to disable the fragmentation on IPV4 ? I am
> misconfiguring something ? Why does the ipip6 has this wrong behavior ?
>
> Thanks in advance,
> Pietro.
>
> Pietro Paolini
> pulsarpie...@aol.com
>
>
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--
浮沉随浪只记今朝笑
--fan
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Re: One confusion about PTE modification on page migration
Hello all,
I think i clear up the confusion myself, and would like to share to you.
For the above case, It's OK it will go to do_anonymous_page(...).
In do_anonymous_page, it will try to get the pte lock, but the pte lock is
already hold by migration routine.
So it will release new-allocated page and let the page fault to fail. I
think it will trigger a-retry for page fault.
That solves my doubt.
Thanks to all of you!
Frank
On Mon, Nov 4, 2013 at 4:45 PM, frank kang wrote:
> Hello all,
>
> I have one confusion about PTE modification on page migration. Can anyone
> help me clarify it?
> As we know, if process access the virtual addresss with null PTE entry, it
> will result in page fault. In page fault routine, it will check PTE entry
> to determine whether it is swap case, (handle_pte_fault)
> if (pte_none(entry)) {
>
> return do_anonymous_page(...);
> }
> return do_swap_page(...);
>
> But, in try_to_unmap_one_anon(...), the pte entry is cleared before it has
> new swap entry.
> pteval = ptep_clear_flush_notify(vma, address, pte);
> ...
> set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
>
> I feel confused about the above atomic operation. That is, If the pte is
> zeroed and new swap entry is not set yet. Some process accesses to the
> address and page fault is raised. In the above routine from page fault,
> pte_none() will return TRUE and it will go to do_anonymous_page(...),
> instead of do_swap_page(...).
>
> Am i right? I don't know if it is my fault or not.
> Can someone help me?
>
> Thanks!
>
> Frank
>
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Festival Shutdown : Kernelnewbies Digest, Vol 36, Issue 6
Hi, Due to Diwali Festival, SLS will be closed from Oct. 31th to Nov. 6th. We will return on Nov. 7th to the office. For urgent matter please call on 001-408-852-0067. For more information about Diwali: http://en.wikipedia.org/wiki/Diwali Regards, Hemal Patel ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
One confusion about PTE modification on page migration
Hello all,
I have one confusion about PTE modification on page migration. Can anyone
help me clarify it?
As we know, if process access the virtual addresss with null PTE entry, it
will result in page fault. In page fault routine, it will check PTE entry
to determine whether it is swap case, (handle_pte_fault)
if (pte_none(entry)) {
return do_anonymous_page(...);
}
return do_swap_page(...);
But, in try_to_unmap_one_anon(...), the pte entry is cleared before it has
new swap entry.
pteval = ptep_clear_flush_notify(vma, address, pte);
...
set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
I feel confused about the above atomic operation. That is, If the pte is
zeroed and new swap entry is not set yet. Some process accesses to the
address and page fault is raised. In the above routine from page fault,
pte_none() will return TRUE and it will go to do_anonymous_page(...),
instead of do_swap_page(...).
Am i right? I don't know if it is my fault or not.
Can someone help me?
Thanks!
Frank
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