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

Yifeng Sun pkusunyifeng at gmail.com
Sat Jun 23 00:36:27 UTC 2018


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

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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