[ovs-dev] [PATCH 3/3] datapath: Do not fail to load on gre protocol conflict

Yifeng Sun pkusunyifeng at gmail.com
Mon Jun 25 17:58:51 UTC 2018


Thanks a lot for the info, I will try them out.

Best,
Yifeng

On Mon, Jun 25, 2018 at 9:00 AM, Gregory Rose <gvrose8192 at gmail.com> wrote:

>
> On 6/22/2018 5:36 PM, Yifeng Sun wrote:
>
> Hi Greg,
>
> I tried 4.4 and 4.16 both with ip_gre module loaded and didn't trigger
> this error.
>
> I will try more, thanks!
>
> Yifeng
>
>
> Try CentOS 7 or RHEL 7.  I think those systems will be the ones most
> likely to exhibit the problem.
>
> Thanks,
>
> - Greg
>
>
>
> On Fri, Jun 22, 2018 at 5:17 PM, Gregory Rose <gvrose8192 at gmail.com>
> wrote:
>
>>
>>
>> On 6/22/2018 4:40 PM, Yifeng Sun wrote:
>>
>> Hi Greg,
>>
>> I am debugging a GRE related issue. Do you mind telling me which kernel
>> version will lead to (err == -EEXIST) here?
>>
>>     else if (err == -EEXIST)
>>
>>                 pr_warn("Cannot take GRE protocol entry - The ERSPAN
>> feature may not be supported\n");
>>
>> Thanks,
>> Yifeng
>>
>>
>> Yifeng,
>>
>> I don't think it is kernel specific unless it is a very new kernel (4.16
>> or newer).
>>
>> The -EEXIST comes from ../datapath/linux/compat/gre.c in rpl_gre_init()
>>
>> int rpl_gre_init(void)
>> {
>>         pr_info("GRE over IPv4 demultiplexor driver\n");
>>
>>         if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
>>                 pr_err("can't add protocol\n");
>>                 return -EEXIST;
>>         }
>>         return 0;
>> }
>>
>> Hope this helps,
>>
>> - Greg
>>
>>
>> On Tue, Jun 5, 2018 at 10:56 AM, Gregory Rose <gvrose8192 at gmail.com>
>> wrote:
>>
>>> On 6/5/2018 10:39 AM, Ben Pfaff wrote:
>>>
>>>> On Tue, Jun 05, 2018 at 09:34:10AM -0700, Gregory Rose wrote:
>>>>
>>>>> On 6/5/2018 9:07 AM, William Tu wrote:
>>>>>
>>>>>> On Mon, Jun 4, 2018 at 1:14 PM, Greg Rose <gvrose8192 at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> The ERSPAN feature depends on the gre kernel module so on systems
>>>>>>> where
>>>>>>> the ERSPAN feature isn't supported the openvswitch kernel module
>>>>>>> would
>>>>>>> attempt to grab the ipv4 GRE protocol entry point and would fail to
>>>>>>> load
>>>>>>> if it could not.
>>>>>>>
>>>>>>> This patch modifies openvswitch to not fail to load when the gre
>>>>>>> kernel
>>>>>>> module is loaded and instead it will print a warning message to the
>>>>>>> kernel system log indicating that the ERSPAN feature may not be
>>>>>>> available.
>>>>>>>
>>>>>>> We need this patch because users are experiencing failures due to the
>>>>>>> conflicts and high priority bugs are resulting.
>>>>>>>
>>>>>>> Signed-off-by: Greg Rose <gvrose8192 at gmail.com>
>>>>>>> ---
>>>>>>>
>>>>>> I read through the patch and look good to me.
>>>>>> Acked-by: William Tu <u9012063 at gmail.com>
>>>>>>
>>>>> Thanks William.
>>>>>
>>>>> After loading the ip_gre and gre kernel modules you can run a 'make
>>>>> check-kmod' test with those modules
>>>>> loaded and the results look good as well.
>>>>>
>>>> I applied this series to master.  I added a reference to the thread
>>>> where Jiri nacked the previous solution.
>>>>
>>>
>>> Thank you!
>>>
>>> - Greg
>>>
>>> _______________________________________________
>>> dev mailing list
>>> dev at openvswitch.org
>>> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>>>
>>
>>
>>
>
>


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