Re: [PATCH] ipv4: fix fib metrics

Alessandro Suardi
2011-03-25T00:12:11Z

On Thu, Mar 24, 2011 at 11:44 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Le jeudi 24 mars 2011 à 15:36 -0700, David Miller a écrit :
>> From: Eric Dumazet <eric.dumazet@gmail.com>
>> Date: Thu, 24 Mar 2011 23:32:26 +0100
>>
>> > Then it doesnt work anymore because it parses an ipip field from
>> > ip route get ...
>> >
>> > $ ip ro get 192.168.1.1
>> > 192.168.1.1 dev wlan0  src 192.168.1.21
>> >     cache  ipid 0x784c mtu 1500 advmss 1460 hoplimit 64
>> >
>> >
>> > Maybe you upgraded iproute2
>>
>> I'm leaning towards app bug too.
>>
>> These default metrics wouldn't get printed before, but now because of
>> how metrics are handled, they will.
>>
>> Userland needs to cope properly with this.
>
>
> BTW, ipip is not always printed (even on old kernels) : One needs to
> actually need ipip generation .
>
> edumazet@edumazet-laptop:~$ ping 4.4.4.4
> PING 4.4.4.4 (4.4.4.4) 56(84) bytes of data.
> ^C
>
> edumazet@edumazet-laptop:~$ ip ro get 4.4.4.4
> 4.4.4.4 dev ppp0  src 10.150.51.210
>    cache  mtu 1500 advmss 1460 hoplimit 64
>
> edumazet@edumazet-laptop:~$ ping -s 2000 4.4.4.4
> PING 4.4.4.4 (4.4.4.4) 2000(2028) bytes of data.
> ^C
>
> edumazet@edumazet-laptop:~$ ip ro get 4.4.4.4
> 4.4.4.4 dev ppp0  src 10.150.51.210
>    cache  ipid 0xf99a mtu 1500 advmss 1460 hoplimit 64
>
>
> This on a 2.6.35 kernel
>
> I suspect Alessandro tool had a bug anyway.

I still contend this is a kernel regression :)

vpnc is a custom build from trunk as of June 2010, with openssl support
to talk to my corporate VPN concentrator:

[root@duff oldconfigs]# vpnc --version
vpnc version 0.5.3-449M
Copyright (C) 2002-2006 Geoffrey Keating, Maurice Massar, others
vpnc comes with NO WARRANTY, to the extent permitted by law.
You may redistribute copies of vpnc under the terms of the GNU General
Public License. For more information about these matters, see the files
named COPYING.
Built with openssl certificate support. Be aware of the
license implications.

Supported DH-Groups: nopfs dh1 dh2 dh5
Supported Hash-Methods: md5 sha1
Supported Encryptions: null des 3des aes128 aes192 aes256
Supported Auth-Methods: psk psk+xauth hybrid(rsa)

My iproute package, on this up-to-date Fedora 14 x86_64, has last been
updated on 20 Nov 2010, and back then I was running 2.6.37-rc2-git4
(I keep around my historical .config files, so I know for sure).

[root@duff ~]# ip -V
ip utility, iproute2-ss100804
[root@duff ~]# rpm -qf /sbin/ip
iproute-2.6.35-6.fc14.x86_64

The behavior of this version of 'ip' as invoked by this version of 'vpnc'
is something that has worked for the last 4 months, and isn't working
right now. Furthermore, previous versions of 'ip' in Fedora 14 were
also working with the same 'vpnc', which means it's actually 9 months
minimum of working behavior.

If some change in the kernel broke my userspace, this usually qualifies
as a regression.

That said, if you can point me to a working version of iproute with the
current kernel, I have no problem in upgrading it :)

Thanks,

--alessandro

"There's always a siren singing you to shipwreck"

(Radiohead, "There There")