Packet corruption in re0

Abdullah Ibn Hamad Al-Marri wearabnet at yahoo.ca
Mon Mar 31 22:29:18 PDT 2008


----- Original Message ----
> From: Pyun YongHyeon <pyunyh at gmail.com>
> To: Ian FREISLICH <ianf at clue.co.za>
> Cc: FreeBSD Current <freebsd-current at freebsd.org>; Robert Backhaus <robbak at robbak.com>
> Sent: Monday, March 17, 2008 8:12:03 AM
> Subject: Re: Packet corruption in re0
> 
> On Fri, Feb 22, 2008 at 10:43:22AM +0200, Ian FREISLICH wrote:
>  > Pyun YongHyeon wrote:
>  > > On Thu, Feb 21, 2008 at 01:18:18PM +0200, Ian FREISLICH wrote:
>  > >  > Pyun YongHyeon wrote:
>  > >  > > On Thu, Feb 21, 2008 at 02:47:43PM +1000, Robert Backhaus wrote:
>  > >  > >  > On Thu, Feb 21, 2008 at 1:50 PM, Pyun YongHyeon  
> wr
>  > ote:
>  > >  > >  > > On Thu, Feb 21, 2008 at 11:03:02AM +1000, Robert Backhaus wrote:
>  > >  > >  > >   > I am experiencing roughly 15% packet corruption on the re 
> inter
>  > face 
>  > >  > on
>  > >  > >  > >   > my freebsd 7/amd64  box.
>  > >  > >  > >   >
>  > >  > >  > >   > FreeBSD gw.flexi.robbak.com 7.0-PRERELEASE FreeBSD 
> 7.0-PRERELEA
>  > SE #8
>  > >  > :
>  > >  > >  > >   > Tue Feb  5 09:49:55 EST 2008
>  > >  > >  > >   > root at gw.flexi.robbak.com:/usr/obj/usr/src/sys/GW  amd64
>  > >  > >  > >   >
>  > >  > >  > >   > Just to make troubleshooting difficult, this problem only 
> shows
>  >  up
>  > >  > >  > >   > after the system has been up for roughly 36 hours, depending 
> on
>  >  the
>  > >  > >  > >   > amount of traffic.
>  > >  > >  > >   >
>  > >  > >  > >
>  > >  > >  > >  I didn't take a look attached tcpdump files but I guess the
>  > >  > >  > >  instability issue was fixed in HEAD. It's not yet MFCed but
>  > >  > >  > >  I'll handle it in a week.
>  > >  > >  > >
>  > >  > >  > >  Would you try re(4) in HEAD?
>  > >  > >  > >
>  > >  > >  > 
>  > >  > >  > OK, I'll do that. What is the best way to do that? csupping to "." 
> se
>  > ems a
>  > >  > >  > bit drastic, and I don't do much with cvs proper. I take it that I 
> sh
>  > ould 
>  > >  > use
>  > >  > >  > anon-cvs to grab the directory, but I don't quite know how.
>  > >  > >  > 
>  > >  > > 
>  > >  > > Copy sys/dev/re/if_re.c, sys/pci/if_rlreg.h in HEAD to your box.
>  > >  > > Due to lack of m_defrag(9) in 7-PRERELEASE/RC, you also have to add
>  > >  > > that function to if_re.c(Copy m_defrag() in sys/kern/uipc_mbuf.c on
>  > >  > > HEAD/RELENG_7 to if_re.c). That would make it build on your box.
>  > >  > 
>  > >  > This doesn't solve the problem that I'm seeing on re(4) interfaces.
>  > >  > It basically shows up as quagga establishing OSPF neighours as
>  > >  > "Exchange/DR" when VLAN hardware tagging is enabled.  I'm running
>  > >  > OSPF over 802.1Q vlans.  Neighbours are correctly negotiated once
>  > >  > VLAN hardware tagging is disabled on the interface.
>  > >  > 
>  > >  > I'll do more debugging.
>  > >  > 
>  > > 
>  > > Hmm. That sounds like different issue to me. I guess I din't change
>  > > any semantics in VLAN H/W tagging. Do you still the same VLAN H/W
>  > > tagging related issues on RELENG_7?
>  > > 
>  > > To narrow down the issue it would be even better to know which parts
>  > > of H/W assistance was broken. For example,
>  > >  - Disable checksum offload for VLAN interface first and check
>  > >    whether quagga works.
>  > 
>  > You can only disable offload on the parent interface.
>  > 
>  > >  - Disable checksum offload for parent interface and check again.
>  > > If you can post tcpdump output for broken conntection it may help a
>  > > lot to diagnose the issue.
>  > 
>  > The only flag affecting this behaviour is vlanhwtag.  Various
>  > permutations of the interface flags make no difference to this
>  > behaviour as long as hardware tagging is enabled.
>  > 
>  > It seems like it's corrupting large packets on transmit when vlanhwtag
>  > is enabled.  From the tcpdump output it looks like a padding or
>  > packet length issue.
>  > 
>  > Here's what tcpdump on the re(4) device thinks it's transmitting:
>  > 
>  > 00:08:a1:3c:32:9c > 00:90:fb:0c:89:7d, ethertype 802.1Q (0x8100), length 
> 1510: vlan 1000, p 0, ethertype IPv4, 196.22.138.92 > 196.22.138.89: OSPFv2, 
> Database Description, length: 1472
>  > 
>  > Here's what was actually recieved by the em(4) device on the
>  > neighbour.  Note the absense of the 801.1Q header:
>  > 
>  > 00:08:a1:3c:32:9c > 00:90:fb:0c:89:7d, ethertype IPv4 (0x0800), length 1506: 
> 196.22.138.92 > 196.22.138.89: OSPFv2, Database Description, length: 1472
>  > 
>  > When vlanhwtagging is disabled, the re(4) device transmits:
>  > 
>  > 00:90:fb:0c:89:7d > 00:08:a1:3c:32:9c, ethertype 802.1Q (0x8100), length 
> 1510: vlan 1000, p 0, ethertype IPv4, 196.22.138.89 > 196.22.138.92: OSPFv2, 
> Database Description, length: 1472
>  > 
>  > and the em(4) device recieves:
>  > 
>  > 00:08:a1:3c:32:9c > 00:90:fb:0c:89:7d, ethertype 802.1Q (0x8100), length 
> 1510: vlan 1000, p 0, ethertype IPv4, 196.22.138.92 > 196.22.138.89: OSPFv2, 
> Database Description, length: 1472
>  > 
>  > Let me know if you need more detailed tcpdump output than I've provided.
>  > 
> 
> I guess I've found a VLAN hardware tagging bug in re(4).
> Please try this one and let me know the result.
> http://people.freebsd.org/~yongari/re/if_re.c
> http://people.freebsd.org/~yongari/re/if_rlreg.h
> 
>  > Ian
>  > 
>  > --
>  > Ian Freislich
>  > 
> 
> -- 
> Regards,
> Pyun YongHyeon


Pyun,

I used it, and I got no bufer space available message, I run a server with heavey http requests and named as we..

so I had to increase the buffer.

www# netstat -m
553/1862/2415 mbufs in use (current/cache/total)
279/1007/1286/65536 mbuf clusters in use (current/cache/total/max)
279/768 mbuf+clusters out of packet secondary zone in use (current/cache)
56/812/868/12800 4k (page size) jumbo clusters in use (current/cache/total/max)
0/0/0/6400 9k jumbo clusters in use (current/cache/total/max)
0/0/0/3200 16k jumbo clusters in use (current/cache/total/max)
920K/5727K/6647K bytes allocated to network (current/cache/total)
0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
0/0/0 sfbufs in use (current/peak/max)
0 requests for sfbufs denied
0 requests for sfbufs delayed
41261 requests for I/O initiated by sendfile
0 calls to protocol drain routines

Can you make a patch for the changes you made in HEAD for RELENG_7?

 Regards,

-Abdullah Ibn Hamad Al-Marri
Arab Portal
http://www.WeArab.Net/






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