freebsd stable - Apr 2010 - pf stalls connection when using route-to

Hi listers,

We recently found that when the traffic passes pf with route-to, the
connection stalls.
Turning off TSO solves the problem. Our pf.conf is very simple:

table <privip> const {10/8, 172.16/12, 192.168/16}
pass out quick route-to (em0 10.1.1.1) from <privip> to ! <privip>
no state

And we have a tcpdump capture file. It shows that there's lots of
duplicate packets and
retransmissions while TSO is enabled. Our NIC is an Intel PRO/1000:

em0: <Intel(R) PRO/1000 Network Connection 6.9.14> port 0x2000-0x201f
mem 0xdf200000-0xdf21ffff irq 18 at device 0.0 on pci4
em0: Using MSI interrupt
em0: [FILTER]

Screenshot: http://cf.files.jnlin.org/with-tso.png

Any suggestion? I just turn off the TSO, but I think it is only a workaround.



Sincerely,

                 Jui-Nan

On Tue, Apr 13, 2010 at 08:17:57PM +0800, Lin Jui-Nan Eric
wrote:
> We recently found that when the traffic passes pf with route-to, the
> connection stalls.
> Turning off TSO solves the problem. Our pf.conf is very simple:
> 
> table <privip> const {10/8, 172.16/12, 192.168/16}
> pass out quick route-to (em0 10.1.1.1) from <privip> to !
<privip> no state
> 
> And we have a tcpdump capture file. It shows that there's lots of
> duplicate packets and
> retransmissions while TSO is enabled. Our NIC is an Intel PRO/1000:
> 
> em0: <Intel(R) PRO/1000 Network Connection 6.9.14> port 0x2000-0x201f
> mem 0xdf200000-0xdf21ffff irq 18 at device 0.0 on pci4
> em0: Using MSI interrupt
> em0: [FILTER]
> 
> Screenshot: http://cf.files.jnlin.org/with-tso.png
> 
> Any suggestion? I just turn off the TSO, but I think it is only a
workaround.
What FreeBSD version?  uname -a output please.

-- 
| Jeremy Chadwick                                   jdc@parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |