iproute2 regression -- ss -u returns an empty list

iproute2 regression -- ss -u returns an empty list

[Mihai Moldovan]

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Hi,

Following up a bug report I received at
http://bugs.x2go.org/cgi-bin/bugreport.cgi?bug=799 it looks like the current
version iproute2's ss utility always returns an empty result set whenever
specifying the -u flag.

The problem has been bisected to 9db7bf15e22b6a1b8bc09c4a1e29571cbca55c94 and is
also affecting version 3.19.0, but most notably 4.0.0+.

I'm not quite sure that's the correct commit, but it does definitely look related.

Even ss -xu, which previously returned a list of UNIX and UDP sockets now
returns nothing on my systems.


Any help with that matter is greatly appreciated.



Mihai


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Re: iproute2 regression -- ss -u returns an empty list

[Mihai Moldovan]

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On 28.04.2015 06:05 AM, Vadim Kochan wrote:> So by default ss prints socket with
CONNECTED state and even UDP can be
> in the CONNECTED state on the Linux,

UDP can be in a CONNECTED state... ooookay. That's probably a conntrack thing.


> so you can specify 'ss -ua' (may be
> some explanation should be added to the ss man page) which
> should print UDP sockets in the any state, AFAIK it was the default
> behaviour before my changes.

Could this please be reverted? It's breaking other stuff that uses ss.

Also: ss -lxua returns an empty list, too. Previously, the families seem to have
been OR'd, while they are now ANDed?



Mihai


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Re: iproute2 regression -- ss -u returns an empty list

[Vadim Kochan]

On Tue, Apr 28, 2015 at 06:33:18AM +0200, Mihai Moldovan wrote:
> On 28.04.2015 06:05 AM, Vadim Kochan wrote:> So by default ss prints socket with
> CONNECTED state and even UDP can be
> > in the CONNECTED state on the Linux,
> 
> UDP can be in a CONNECTED state... ooookay. That's probably a conntrack thing.
> 
> 
> > so you can specify 'ss -ua' (may be
> > some explanation should be added to the ss man page) which
> > should print UDP sockets in the any state, AFAIK it was the default
> > behaviour before my changes.
> 
> Could this please be reverted? It's breaking other stuff that uses ss.
> 
> Also: ss -lxua returns an empty list, too. Previously, the families seem to have
> been OR'd, while they are now ANDed?
> 
> 
> 
> Mihai
> 

I will try to fix this ...

Re: iproute2 regression -- ss -u returns an empty list

[Mihai Moldovan]

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On 28.04.2015 06:47 AM, Vadim Kochan wrote:
> On Tue, Apr 28, 2015 at 06:33:18AM +0200, Mihai Moldovan wrote:
>> On 28.04.2015 06:05 AM, Vadim Kochan wrote:> So by default ss prints
>> socket with CONNECTED state and even UDP can be
>>> in the CONNECTED state on the Linux,
>> 
>> UDP can be in a CONNECTED state... ooookay. That's probably a conntrack 
>> thing.
>> 
>> 
>>> so you can specify 'ss -ua' (may be some explanation should be added to 
>>> the ss man page) which should print UDP sockets in the any state, AFAIK 
>>> it was the default behaviour before my changes.
>> 
>> Could this please be reverted? It's breaking other stuff that uses ss.
>> 
>> Also: ss -lxua returns an empty list, too. Previously, the families seem
>> to have been OR'd, while they are now ANDed?
>> 
>> 
>> 
>> Mihai
>> 
> 
> I will try to fix this ...

Thanks!

To be a bit more verbose about the rationale:

Changing the default behavior is generally a bad idea, unless strictly necessary
(e.g., if the previous default behavior was buggy anyway), because it may break
other software. Please try introducing behavioral changes via new options.

That way, dependencies will still work fine and anyone who wants to use the new
behavior can explicitly do so via a switch.

I could work around this by checking ss' version, but that turns out to be a
pain, too, because ss -V reports something like this:

"ss utility, iproute2-ss150413"

Not exactly a "friendly" version like "3.19.0" or "4.0.0" to check against...



Mihai



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Re: iproute2 regression -- ss -u returns an empty list

[Vadim Kochan]

On Tue, Apr 28, 2015 at 07:07:56AM +0200, Mihai Moldovan wrote:
> On 28.04.2015 06:47 AM, Vadim Kochan wrote:
> > On Tue, Apr 28, 2015 at 06:33:18AM +0200, Mihai Moldovan wrote:
> >> On 28.04.2015 06:05 AM, Vadim Kochan wrote:> So by default ss prints
> >> socket with CONNECTED state and even UDP can be
> >>> in the CONNECTED state on the Linux,
> >> 
> >> UDP can be in a CONNECTED state... ooookay. That's probably a conntrack 
> >> thing.
> >> 
> >> 
> >>> so you can specify 'ss -ua' (may be some explanation should be added to 
> >>> the ss man page) which should print UDP sockets in the any state, AFAIK 
> >>> it was the default behaviour before my changes.
> >> 
> >> Could this please be reverted? It's breaking other stuff that uses ss.
> >> 
> >> Also: ss -lxua returns an empty list, too. Previously, the families seem
> >> to have been OR'd, while they are now ANDed?
> >> 
> >> 
> >> 
> >> Mihai
> >> 
> > 
> > I will try to fix this ...
> 
> Thanks!
> 
> To be a bit more verbose about the rationale:
> 
> Changing the default behavior is generally a bad idea, unless strictly necessary
> (e.g., if the previous default behavior was buggy anyway), because it may break

Yes the previous behaviour was buggy ... And that was the reason.

> other software. Please try introducing behavioral changes via new options.
> 
> That way, dependencies will still work fine and anyone who wants to use the new
> behavior can explicitly do so via a switch.
> 
> I could work around this by checking ss' version, but that turns out to be a
> pain, too, because ss -V reports something like this:
> 
> "ss utility, iproute2-ss150413"
> 
> Not exactly a "friendly" version like "3.19.0" or "4.0.0" to check against...
> 
> 
> 
> Mihai
> 
> 

Re: iproute2 regression -- ss -u returns an empty list

[Vadim Kochan]

On Tue, Apr 28, 2015 at 03:22:33AM +0200, Mihai Moldovan wrote:
> Hi,
> 
> Following up a bug report I received at
> http://bugs.x2go.org/cgi-bin/bugreport.cgi?bug=799 it looks like the current
> version iproute2's ss utility always returns an empty result set whenever
> specifying the -u flag.
> 
> The problem has been bisected to 9db7bf15e22b6a1b8bc09c4a1e29571cbca55c94 and is
> also affecting version 3.19.0, but most notably 4.0.0+.
> 
> I'm not quite sure that's the correct commit, but it does definitely look related.
> 
> Even ss -xu, which previously returned a list of UNIX and UDP sockets now
> returns nothing on my systems.
> 
> 
> Any help with that matter is greatly appreciated.
> 
> 
> 
> Mihai
> 


Hi Mihai,

Seems I have a fixed version, I tested it localy with different
option combinations, and now there should be no issues when specifying
different families.

Would you be able to test it ? How I can provide a fixed version to you -
by patch or I can push to my github and give you a link ?

Thanks,

Re: iproute2 regression -- ss -u returns an empty list

[Mihai Moldovan]

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Hi Vadim,


On 28.04.2015 01:21 PM, Vadim Kochan wrote:
> Seems I have a fixed version, I tested it localy with different
> option combinations, and now there should be no issues when specifying
> different families.

Thanks for the quick work! I'm happy to test.


> Would you be able to test it ? How I can provide a fixed version to you -
> by patch or I can push to my github and give you a link ?

I don't mind, any way is fine. I can work either way.



Mihai



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Re: iproute2 regression -- ss -u returns an empty list

[Vadim Kochan]

On Tue, Apr 28, 2015 at 03:14:31PM +0200, Mihai Moldovan wrote:
> Hi Vadim,
> 
> 
> On 28.04.2015 01:21 PM, Vadim Kochan wrote:
> > Seems I have a fixed version, I tested it localy with different
> > option combinations, and now there should be no issues when specifying
> > different families.
> 
> Thanks for the quick work! I'm happy to test.
> 
> 
> > Would you be able to test it ? How I can provide a fixed version to you -
> > by patch or I can push to my github and give you a link ?
> 
> I don't mind, any way is fine. I can work either way.
> 
> 
> 
> Mihai
> 
> 

Hi Stephen,

I just saw that Linux 4.0.1 was released so I assume that you will
prepare the v4.0.1 tag for iproute2 too, but would you please wait until
this bug will be fixed ? I already have a working patch (from my point
of view it works better than before), so I'd like to wait when Mihai
will test the patch which I have sent directly to him.

Thanks,
Vadim