[reSIProcate] DnsResult blacklistLast,greylistLast question.

[Sergey Pavlov]

Hi, resiprocate devels.
I just want to return to the topic described in the quoted email below i.e.
to the question of separate
transport/target blacklisting. I am colleague of the mail author and I want
a clarify a situation
a little bit. The initial schema of SIP communication was following:

UA1  -> Proxy(resiprocate stack) ->UA2

where
1) The Proxy was configured with UDP and TCP transports.
2) UA1 and UA2 used only UDP transport and didn't have TCP support enabled.
3) UA1 sent INVITE with broken To header field
4) UA2 detected malformed To header filed and answered with 500 response
without(!) To field
5) The resiprocate detected malformed response and ignored that and UA2 was
greylisted on some time.
6) As result all requests targeted to UA2 were sent over TCP during
greylist period. However, taking into account
taht UA2 doesn't support TCP we just had a broken signalling during this
period of time.

Such behaviour is more or less acceptable in case when UA2 is just end-user
UA. But in our case it can
be some vendor gateway or our own B2BUA so we simply face out-of-order
condition for large amount of calls.

To put it simply, we have a situation when an unanswered SIP transaction
leads to out-of-order service
condition during significant period of time. So the provided patch is aimed
to introduce some control
for grey-listing mechanism. Frankly speaking, complete disabling of
grey-list functionality also will help
in our case. The question is - is there possibilty to make it without
respirocate patching?

--
Best regards,
Sergey Pavlov

> Dear resiprocate devels,
> resiprocate version 1.8.8
>
> I use proxy,built above resip stack. In particular, there are a fiew
intermediate proxy servers: N1,N2,N3.

> I've met next issue:
> 1) there is an active session.
> 2) some client starts one more session,sending malformed sip message to
proxy1, proxy1
> retransmits that message to Proxy2 and proxy2 responds with 500 Server
internal error.
> Proxy1 tries to retransmit that message several times and after the last
one it
> penalizes given transport by black listing.
> 3) At the same time session from item1 has not been finished yet. If any
participant from
> session1 will send any sip message - TransportSelector will generate
TransportFailure or
>TCP transport will be selected if it is configured - as result session1
becomes broken/hung.
>
> I think UAC penalization - is good idea,but proxy penalization leads to
undefined behaviour.
>
> Considering this I  would like to ask a few questions,if you don't mind:
> 1) Is it possible to add some exception list to
DnsResult::blackListLast/DnsResult::greyListLast stuff?
> 2) Could you please take a look on provided patch,which provides some
kind of solution?
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