[SR-Users] Via in locally generated PUBLISH (using different presence server address)

[Asgaroth]

Hi Daniel,

I've just sent the captures on to you privately.

Thanks

On 09/08/2016 08:34, Daniel-Constantin Mierla wrote:
> Hello,
>
> can you send the pcap with sip messages for such situation? It will help
> to understand if Via is used corerctly for replies.
>
> Cheers,
> Daniel
>
>
> On 08/08/16 18:51, Asgaroth wrote:
>> Hi All,
>>
>> I have a configuration where we run a multi-homed proxy/loadbalancer
>> and a seperate internal presence server. We then use
>> pua/pua-dialoginfo on the proxies to publish dialog state to the
>> internal presence server.
>>
>> The proxies listen on udp:external_ip:5062 and udp:internal_ip1:5060.
>> The presence server listens on udp:internal_ip2:5060 on a seperate
>> server.
>>
>> The problem I am coming accross is that when kamailio generates a
>> PUBLISH message for some dialogs it creates the via header with
>> address external:ip:5062, however the pua module is configured to send
>> to the presence server address on internal_ip2:5060. I have a route
>> which forces the sending socket ($fs) to be udp:internal_ip1:5060.
>>
>> What happens then is that the presence server tries to send the 200
>> reply to the PUBLISH message back to internal_ip1:5062 (when it should
>> be internal_ip1:5060), I'm thinking this is because the Via header has
>> host as external_ip:5062.
>>
>> Is it possible, from event-route[tm:local-request] to rewrite the via
>> header so that it reflects internal_ip1:5060 instead of external_ip:5062?
>>
>> I did try the following snippet from event-route[tm:local-request],
>> but I got module parse errors on the Via header:
>>
>> if (is_method("PUBLISH")) {
>>        subst_hf("Via", "/ 1\.2\.3\.[0-9]+:5062;/
>> $sel(cfg_get.socket.internal_ip);/", "f");
>> }
>>
>> [7370]: ERROR: <core> [parser/parse_via.c:2607]: parse_via():
>> ERROR:parse_via on <1> state 5 (default)
>> [7370]: ERROR: <core> [parser/parse_via.c:2708]: parse_via(): ERROR:
>> parse_via on: <SIP/2.0/UDP
>> external_ip:5062;branch=z9hG4bK96eb.0f014ae4000000000000000000000000.0#015#012
>> internal_ip1;
>> [7370]: ERROR: <core> [parser/parse_via.c:2712]: parse_via(): ERROR:
>> parse_via parse error, parsed so far:<SIP/2.0/UDP
>> external_ip:5062;branch=z9hG4bK96eb.0f014ae4000000000000000000000000.0#015#012
>> [7370]: ERROR: <core> [parser/msg_parser.c:125]: get_hdr_field():
>> ERROR: get_hdr_field: bad via
>> [7370]: INFO: <core> [parser/msg_parser.c:338]: parse_headers():
>> ERROR: bad header field [Via: SIP/2.0/UDP 1]
>> [7370]: ERROR: <core> [parser/msg_parser.c:690]: parse_msg(): ERROR:
>> parse_msg: message=<PUBLISH sip:user at domain;transport=UDP
>> SIP/2.0#015#012Via: SIP/2.0/UDP
>> external_ip:5062;branch=z9hG4bK96eb.0f014ae4000000000000000000000000.0#015#012
>> internal_ip1;To: <sip:user at domain;transport=UDP>#015#012From:
>> <sip:user at domain;transport=UDP>;tag=3e8fdaca277026bf3e6d75c5e5313096-f162#015#012CSeq:
>> 10 PUBLISH#015#012Call-ID:
>> 5634294b786134b3-7370 at external_ip#015#012Content-Length:
>> 692#015#012User-Agent: kamailio (bfievklb04)#015#012Max-Forwards:
>> 70#015#012Event: dialog#015#012Expires: 10901#015#012Content-Type:
>> application/dialog-info+xml#015#012#015#012<?xml
>> version="1.0"?>#012<dialog-info
>> xmlns="urn:ietf:params:xml:ns:dialog-info" version="0" state="full"
>> entity="sip:user at domain;transport=UDP">#012  <dialog
>> id="mvqXXaAr24DHdfsffYKZeA.." call-id="mvqXXaAr24DHdfsffYKZeA.."
>> direction="initiator">#012 <state>Trying</state>#012    <remote>#012
>> <identity>sip:1234567 at domain;transport=UDP</identity>#012 <target
>> uri="sip:1234567 at domain;transport=UDP"/>#012 </remote>#012
>> <local>#012 <identity>sip:user at domain;transport=UDP</identity>#012
>> <target uri="sip:user at domain;transport=UDP"/>#012 </local>#012
>> </dialog>#012</dialog-info>#012>
>> [7370]: ERROR: <core> [msg_translator.c:3057]:
>> build_sip_msg_from_buf(): parsing failed
>> [7370]: ERROR: tm [uac.c:163]: uac_refresh_hdr_shortcuts(): failed to
>> parse msg buffer
>> [7370]: ERROR: tm [uac.c:487]: t_uac_prepare(): failed to refresh
>> header shortcuts
>> [7370]: ERROR: pua [send_publish.c:700]: send_publish(): in t_request
>> tm module function
>> [7370]: ERROR: pua_dialoginfo [dialog_publish.c:358]:
>> dialog_publish(): while sending publish
>>
>> To me, it looks like the replace section of the subst_hf sub
>> expression is being appended to the end of the via header instead of
>> replacing the address section found.
>>
>> I have sanitized the above output to not show internal details, but if
>> you need it, I can send it on to you privately.
>>
>> Am I going about this issue in the correct way, and, if so, where am I
>> going wrong with the subst_hf snippet above?
>>
>> Kamailio version is 4.3.6.
>>
>> Any pointers/tips/trciks are greatly appreciated.
>>
>> Thanks
>>
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