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On Sun, Mar 26, 2017 at 9:31 PM, Sridhar Gaddam <sgaddam at redhat.com> wrote:

>
>
> On Fri, Mar 24, 2017 at 7:27 PM, Brian Haley <haleyb.dev at gmail.com> wrote:
>
>> On 03/24/2017 06:41 AM, Ghanshyam Mann wrote:
>>
>>> Hi All,
>>>
>>> Tempest is testing SG rule creation and pinging scenario tests with
>>> ethertype='IPv6' and protocol='icmp' [0].
>>> In case of ethertype='IPv6', currently neutron accept protocol type
>>> as 'icmp', 'icmpv6' and 'ipv6-icmp' which again seems like duplication
>>> of SG rules bug on neutron side but not sure [1]
>>>
>>> But it seems like some driver does not work with 'icmp' on IPv6, at
>>> least ODL as mentioned in bug [2]. Where few others like ML2/OVS
>>> iptables driver convert 'icmp' to 'icmpv6' when ethertype='IPv6' and had
>>> no issue with 'icmp'.
>>>
>>> IMO neutron should keep accepting 'icmp' for IPv6 for backward
>>> compatibility and legacy usage and tempest should test 'icmp' also along
>>> with other protocol type.
>>> But we need more feedback on that what is right way (as per backward
>>> compatibility pov) and recommended way for having best behaviour for SG
>>> rules on IPv6. What best can work for all plugins also?
>>>
>>
>> Thanks for raising this issue.  Let me just restate it a little so it's
>> clear.
>>
>> 1. One can create an IPv6 rule using protocol value "icmp" today, and the
>> base security group code does the right thing changing the rule to be
>> correct for the underlying implementation, for example, "ipv6-icmp" for
>> iptables.  It doesn't look like all other drivers handle this properly.
>>
>> ​Well, let the Neutron API accept multiple values like
> "icmp/icmpv6/ipv6-icmp", but IMO it should store a single Security Group
> rule in the DB and raise "Duplicate error when similar rule is configured
> once again".
> Currently, Neutron treats each of them as a different Security Group rule
> and stores them as separate entries in the DB.
> However, IPtables Firewall driver in Neutron is converting[1] the
> "ethertype=IPv6 and protocol=icmp" as a request to ICMPv6 and applying the
> necessary ip-table rule.
> https://github.com/openstack/neutron/blob/stable/newton/
> neutron/agent/linux/iptables_firewall.py#L373
>
> Since this is not a documented behavior, other firewall drivers (which I
> guess could be an issue even with OVS firewall driver) may be missing this
> info.​
>

​++ for this, documentation could have helped this better way. ​



>
>
>> 2. The neutron API will accept multiple values - "icmp", "ipv6-icmp" and
>> "icmpv6" for an IPv6 rule, but it will create unique database entries for
>> each (I just verified that).  While that shouldn't create multiple entries
>> in the base iptables code, it will probably generate a warning in the logs
>> about a duplicate being suppressed.
>>
>>
>> So there are a few things that could be done:
>>
>> 1. Drivers need to accept "icmp" in order to be backwards-compatible with
>> the current code.
>>
>> 2. Duplicates should be detected and generate 409 (?) errors.
>>
>> 3. We should add a migration (IMO) where any duplicates are squashed.
>>
>> ​Agree with your points.
>


​Yes, 409 on same type again make sense. And it can be documented properly
that 'icmp'​ will be treated same as other protocol type for
​
Ethertype=IPv6 and user will get 409 if they try to create and expect 2
different SG rules with those different protocol_type.
This is something change in current behavior where both requests('icmp' and
'icmpv6') are treated as 2 separate rules. And so this new Tempest tests
will fail [1] which can be modified later.

With those points and current situation, I feel Tempest should tests the
current behavior proposed in [1] which will discover the drivers for point
1. Later based on bug [2] consensus we can change the tests accordingly.
I want to merge Tempest changes so that while changing anything on neutron
side, we know exactly what behavior we are going to change and its impact
etc.
Please leave comment on patch if any more feedback.



> ​
>
>> The open question is, do we want to change the DB to have a different
>> value here, like "icmpv6" ?  We could obviously add a migration where we
>> update the value.  The problem is that flag day could pose a problem if
>> out-of-tree drivers don't support the new value.  I think we should leave
>> it "icmp" for that reason, thoughts from others?
>>
>> IMO, the out-of-tree drivers should be supporting the icmpv6 protocol​
> rule properly. There is a possibility that they may hit this issue[
> https://bugs.launchpad.net/tempest/+bug/1671366] for not being aware that
> a request for "
> ​​
> Ethertype=IPv6 and protocol=icmp" should be treated as ICMPv6 SG rule.
>
> Please see the DB entries for the two SG rules -
> http://paste.openstack.org/show/604190/
>
>
>
​..1
https://review.openstack.org/#/c/431276/16/tempest/api/network/test_security_groups.py

..2 https://bugs.launchpad.net/neutron/+bug/1582500

-gmann​





>
>
>> -Brian
>>
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