Re: 2.6.13-mm2

J.A. Magallon
2005-09-11T00:58:40Z

On 09.11, J.A. Magallon wrote:
>
> On 09.11, Patrick McHardy wrote:
> > Andrew Morton wrote:
> > > "J.A. Magallon" <jamagallon@able.es> wrote:
> > >
> > >>I can not ifup an interface while iptables is using it.
> > >>Is this expected behaviour ?
> > >
> > > Maybe it's expected, but breaking existing userspace is a serious issue.
> >
> > No, its not expected.
> >
> > >>There is a possible bug (IMHO) in Mandrake initscripts, that start iptables
> > >>before network interfaces, but this had always worked.
> > >>
> > >>Any ideas ?
> >
> > What's happening when you try to set the interface up? Please
> > provide output of ifup and strace of the failing command. Thanks.
>
> werewolf:~# ifdown eth0
> werewolf:~# service iptables start
> Applying iptables firewall rules:
> [ OK ]
> werewolf:~# iptables -v -t nat -L
> Chain PREROUTING (policy ACCEPT 2 packets, 156 bytes)
> pkts bytes target prot opt in out source destination
>
> Chain POSTROUTING (policy ACCEPT 5 packets, 300 bytes)
> pkts bytes target prot opt in out source destination
> 0 0 MASQUERADE all -- any eth0 anywhere anywhere
>
> Chain OUTPUT (policy ACCEPT 5 packets, 300 bytes)
> pkts bytes target prot opt in out source destination
> werewolf:~# iptables -v -t filter -L
> Chain INPUT (policy ACCEPT 257 packets, 51631 bytes)
> pkts bytes target prot opt in out source destination
>
> Chain FORWARD (policy DROP 0 packets, 0 bytes)
> pkts bytes target prot opt in out source destination
> 0 0 ACCEPT all -- eth0 eth1 anywhere anywhere state RELATED,ESTABLISHED
> 0 0 ACCEPT all -- eth1 eth0 anywhere anywhere
>
> Chain OUTPUT (policy ACCEPT 251 packets, 51163 bytes)
> pkts bytes target prot opt in out source destination
>
> werewolf:~# ifup eth0
>
> Determining IP information for eth0...Operation failed.
> failed.
>
> I traced the problem to pump, and I did a diff between strace of pump
> when it works and when it doesnt (witout and with iptables started):
>
> socket(PF_FILE, SOCK_STREAM, 0) = 3
> connect(3, {sa_family=AF_FILE, path="/var/run/pump.sock"}, 20) = 0
> write(3, "\0\0\0\0eth0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\300"..., 4280) = 4280
> -read(3, "\1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 4280) = 4280
> -exit_group(0) = ?
> -Process 7931 detached
> +read(3, "\1\0\0\0\1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 4280) = 4280
> +socket(PF_FILE, SOCK_STREAM, 0) = 4
> +connect(4, {sa_family=AF_FILE, path="/var/run/pump.sock"}, 20) = 0
> +write(4, "\0\0\0\0eth0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\300"..., 4280) = 4280
> +read(4, "\1\0\0\0\1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 4280) = 4280
> +write(2, "Operation failed.\n", 18Operation failed.
> +) = 18
> +exit_group(1) = ?
> +Process 7822 detached
>
> pump seems to write something in the socket, try to read it again and gets
> different results.
>
> Note, my iptables are modular and I did not unload the modules, just stopped
> them with 'service iptables stop'. Digging further, if I just do
> iptables -t nat -F, pump works again.
>
> Hope this helps.
>

And I also get this on syslog:

Sep 11 02:56:58 werewolf kernel: MASQUERADE: eth0 ate my IP address
Sep 11 02:56:58 werewolf kernel: MASQUERADE: eth0 ate my IP address

--
J.A. Magallon <jamagallon()able!es> \ Software is like sex:
werewolf!able!es \ It's better when it's free
Mandriva Linux release 2006.0 (Cooker) for i586
Linux 2.6.13-jam3 (gcc 4.0.1 (4.0.1-5mdk for Mandriva Linux release 2006.0))