[OpenSER-Users] The Via Header of CANCEL Message

[Bogdan-Andrei Iancu]

Klaus,

you are right! in stateful mode, the CANCEL is routed hop by hop but not 
constructed (at least not by openser) - that is something I have on the 
todo list and really want to have in 1.3

regards,
bogdan

Klaus Darilion wrote:
>
>
> Bogdan-Andrei Iancu wrote:
>> Klaus,
>>
>> CANCEL is hop-by-hop only in stateful processing and in this case, 
>> yes, it has only on VIA. But if you have stateless processing, CANCEL is 
>
>      ^^should
>
> but in fact, also when using tm the CANCEL has 2 Via headers:
>
> U 88.198.53.113:6060 -> 83.136.32.160:5060
> CANCEL sip:klaus.darilion at nic.at43.at SIP/2.0.
> Max-Forwards: 10.
> Record-Route: <sip:88.198.53.113:6060;lr=on;ftag=d421fe7e>.
> Via: SIP/2.0/UDP 88.198.53.113:6060;branch=z9hG4bKdd22.f7f861b6.0.
> Via: SIP/2.0/UDP 
> 10.10.0.50:13946;received=83.136.33.3;branch=z9hG4bK-d87543-2e40397a3e383c6b-1--d87543-;rport=13946. 
>
> To: ...
> ...
>
>
>
> regards
> klaus
>
>> end-2-end and it will have multiple VIAs...
>>
>> Does 3665 obsoletes stateless SIP or it is just not covering it???
>>
>> regards,
>> bogdan
>>
>> Klaus Darilion wrote:
>>> Looks like it is defined clearly and openser is not 100% standard 
>>> conform.
>>>
>>> regards
>>> klaus
>>>
>>> fancy wrote:
>>>  
>>>> Hi Klaus:
>>>> RFC 3665 page 54 line 4:
>>>>    A CANCEL constructed by a
>>>>    client MUST have only a single Via header field value matching the
>>>>    top Via value in the request being cancelled.
>>>>
>>>> and RFC 3665 at page 53:
>>>>    CANCEL is referred to as a "hop-by-hop" request, since it is
>>>>    responded to at each stateful proxy hop.
>>>>
>>>> and RFC 3665 at page 21:
>>>>    Client: A client is any network element that sends SIP requests
>>>>          and receives SIP responses.  Clients may or may not interact
>>>>          directly with a human user.  User agent clients and 
>>>> proxies are
>>>>          clients.
>>>>
>>>> So, for my opinion, the role of proxy in this case of RFC 3665 
>>>> section 3.8 is a client when it sends CANCEL message to Bob.
>>>>
>>>> If I misunderstand any RFC meanings, please correct me.
>>>> Thank you very much.
>>>>
>>>> Best Regards,
>>>> Fangyu Ling
>>>>
>>>>
>>>>   
>>>>> fancy wrote:
>>>>>     
>>>>>> According to RFC 3665 section 3.8 and RFC 3261 section 9,
>>>>>> there is only one via header in CANCEL message
>>>>>> (message F11, F13 at page 72 of RFC 3665).
>>>>>>         
>>>>> Hi!
>>>>>
>>>>> I could find it in RFC 3665, but not in 3261. Where exactly in RFC 
>>>>> 3261
>>>>> is mentioned that the CANCEL has only 1 Via header?
>>>>>
>>>>> Further, the example has only one Via header - but I could not 
>>>>> find any
>>>>> definition if this is a MUST or not.
>>>>>
>>>>>     
>>>>>> How can I remove the 2nd via header?
>>>>>>         
>>>>> You would have to modify tm module and change the code which 
>>>>> generates
>>>>> the CANCEL message.
>>>>>
>>>>> regards
>>>>> klaus
>>>>>
>>>>>       
>>>
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>>>   
>>
>