[Pkg-swan-devel] Bug#874503: Bug#874503: warn about unsupported kernel versions

Daniel Pocock daniel at pocock.pro
Fri Sep 8 15:42:46 UTC 2017


On 08/09/17 15:36, Yves-Alexis Perez wrote:
> On Wed, 2017-09-06 at 15:57 +0100, Daniel Pocock wrote:
>> There is some issue with kernel version 4.11
>>
>> strongswan wasn't working, I looked with tcpdump and saw messages like
>> "truncated-udplength 0"
>>
>> I used a search engine to find out about that string and it took me to
>> this page:
>>
>> https://www.linuxquestions.org/questions/linux-networking-3/strongswan-ikev2
>> -clients-can-access-everything-but-strongswan-machine-itself-truncated-udp-
>> length-0-a-4175606751/
>>
>> with the quote "So this appears to be a kernel-related issue; I had
>> updated to 4.11.2 recently. Downgrading back to 4.10.9, without any
>> other changes to my setup, resolves the problem."
>>
>> I downgraded my own system to a 4.9 kernel and it worked again.
>>
>> There was no obvious error from StrongSWAN in the console or in the logs
>> to tell me about this, I can imagine some people losing a lot of time on
>> something like this if they don't come across this page.
> Well, that's a bug in the Linux kernel then, which should be fixed there. I
> don't really see the point in adding documentation for kernel bugs in
> strongSwan, although I sympathize about the lack of information.
>
> When you have identified the relevant kernel versions, commit IDs fixing the
> bug etc., feel free to add them to that bug.


If the kernel gives any indication of this condition to the StrongSWAN
process in userspace, then it would be very desirable for the process to
report that, even if it is just one line in the log with the severity of
warning or error.



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