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

[Daniel-Constantin Mierla]

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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-- 
Daniel-Constantin Mierla
http://www.asipto.com - http://www.kamailio.org
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