[asterisk-users] Workaround for bug in Linksys Firmware 6.1.3(a) (or greater)

[James Lamanna]

On Tue, Jun 22, 2010 at 4:31 PM, Ryan Wagoner <rswagoner at gmail.com> wrote:
> On Tue, Jun 22, 2010 at 6:26 PM, James Lamanna <jlamanna at gmail.com> wrote:
>> On Tue, Jun 22, 2010 at 12:06 PM, Stefan Schmidt <sst at sil.at> wrote:
>>> James Lamanna schrieb:
>>>> If you've used Linksys phones against recent Asterisk 1.4.x you may
>>>> have noticed
>>>> that they may drop registration for a quick bit and then go back to being ok
>>>> if your phone is behind NAT.
>>>> If you turn Asterisk's sip debug information on, you'll probably find
>>>> errors like these in your logs:
>>>>
>>>> NOTICE[30179] chan_sip.c: Correct auth, but based on stale nonce
>>>> received from '"999911" <sip:999911 at 208.90.186.10>'
>>>>
>>>> I believe I have determined that this is caused by a bug in the
>>>> Linksys firmware that is related to the NAT Keep-Alive packets.
>>>> Because recent Asterisk 1.4.x's do not establish a SIP dialog for
>>>> NOTIFY requests, the "489 Bad Event"
>>>> replies were going back to the wrong address if your phone was behind NAT.
>>>> This lack of reply would cause the next REGISTER message to use the
>>>> same nonce as the previous REGISTER,
>>>> resulting in the "stale nonce" errors and temporarily dropping
>>>> registration. I've also seen the lack of response to
>>>> the NAT keep-alive cause the phone to stop being able to register
>>>> completely as well.
>>>>
>>>> Below I've posted a patch that responds with a 200 OK to these
>>>> keep-alive requests, and I believe
>>>> also solves the temporary loss of registration problem, though more
>>>> testing in different environments
>>>> for those who experience this problem would be greatly appreciated.
>>>>
>>>> The patch is against 1.4.32.
>>>>
>>>> -- James
>>>>
>>> Hello,
>>>
>>> you also just could set the NAT KEEP ALIVE MESSAGE on Ext 1 from $NOTIFY
>>> to $OPTIONS and make this extension in your default context:
>>> exten => s,1,hangup
>>>
>>> and you also would get a 200 ok for the keep alive package.
>>>
>>> IMHO a stale nonce would only occur when a user tries to register faster
>>> than 3600s cause of the register timeout used in asterisk. Maybe you
>>> should also try to set a higher register timeout on your phones. but i
>>> dont have an 1.4 system running, only around 2k of linksys phones on a
>>> 1.2.40 and 300 on 1.6.1.18 and i dont see this problem there.
>>
>> I'm not sure how this works.
>> The OPTIONS message fails chan_sip.c:parse_request() so the OPTIONS
>> message never gets processed.
>> The options message I receive from a Linksys942 6.1.3(a) looks like this:
>>
>> <--- SIP read from xxx.xxx.xxx.xxx:8037 --->
>> OPTIONS
>> <------------->
>>
>> -- James
>>
>> --
>
> I had the same result when using $OPTIONS on a SPA941 phone with
> firmware 5.1.8. I am running Asterisk 1.6.2.9 that has the keep-alive
> support, however I still see Asterisk sending a 489 Bad Event. I just
> reopened the issue and provided the necessary debug log at
> https://issues.asterisk.org/bug_view_page.php?bug_id=17379

Ryan,
This is most likely because the packet never makes it to handle_request_notify.
I haven't looked at the code for 1.6.2.9 yet, but in 1.4.32 without my
patch, the
NOTIFY request would never make it out of find_call() and return early with a
489 Bad Event response.

Were you getting any response at 1.6.2.9 with the OPTIONS message?

-- James