[OpenSER-Users] Snom number-guessing and OpenSER

Klaus Darilion klaus.mailinglists at pernau.at
Mon Oct 8 13:02:05 CEST 2007



Edoardo Serra schrieb:
> Tnx Klaus for your answer.
> 
> If I dump the packet from Perl I cannot see the Via header added by 
> OpenSER, is something wrong in my openser.cfg or perl module 'sees' the 
> packet before OpenSER manipulation ??

Yes - the perl module sees the original received message. I dirty 
workaround would be to t_relay the message to openser again, and in the 
second iteration forward the request to perl and then drop it (without 
generating a second transaction).

regards
klaus

> 
> About the to-tag I'll have a look at Net::SIP if it has a way to 
> generate one.
> 
> regards
> 
> Edoardo
> 
> 
> Klaus Darilion ha scritto:
>> Some hints:
>>
>> A reply should have a to-tag.
>> Openser adds a Via header during forwarding (with a generated 
>> branch.id). This branch.id is also used for transaction matching.
>>
>> regards
>> klaus
>>
>>
>> Edoardo Serra schrieb:
>>> Hi all,
>>>     I'm trying to develop an extension to support SNOM's number 
>>> guessing feature (I don't know if it's somehow a standard but 
>>> description on how it works is here: 
>>> http://kb.snom.com/kb/index.php?View=entry&CategoryID=14&EntryID=14)
>>>
>>> As I have to do some 'complicated' db queries I was thinking to use 
>>> PERL module to handle number guessing request from the phone.
>>>
>>> I see there's no way (please correct me if I'm wrong) from OpenSER, 
>>> neither from OpenSER::Message, to send a stateless reply with a 
>>> customized body (SNOM says that possible number completion shoud be 
>>> included in the body of a 200 OK reply).
>>>
>>> For this reason I have to use Net::SIP to generate the reply packet 
>>> but I'm doing something wrong as OpenSER is not forwarding it back to 
>>> the client.
>>>
>>> Test client is a Snom 360 and is behind a NAT, OpenSER has a public IP
>>>
>>> Here is my routing logic in openser.cfg
>>>
>>> ------------------- BEGIN openser.cfg
>>> route{
>>>
>>>         if (!mf_process_maxfwd_header("10")) {
>>>                 sl_send_reply("483","Too Many Hops");
>>>                 exit;
>>>         };
>>>         if (msg:len >=  2048 ) {
>>>                 sl_send_reply("513", "Message too big");
>>>                 exit;
>>>         };
>>>
>>>         if (nat_uac_test("19")) {
>>>                 fix_nated_contact();
>>>                 force_rport();
>>>                 setbflag(6);
>>>         }
>>>
>>>
>>>         if (method=="PUBLISH") {
>>>                 if ($hdr(Event)=="number-guessing") {
>>>                         log("- Initial PUBLISH\n");
>>>                         t_newtran();
>>>                         t_on_reply("1");
>>>                         perl_exec("numberguessing");
>>>                         exit;
>>>                 }
>>>                 sl_send_reply("501", "Not implemented");
>>>                 exit;
>>>         }
>>>
>>>         if (method=="REGISTER") {
>>>                 if (nat_uac_test("19")) {
>>>                         fix_nated_contact();
>>>                         force_rport();
>>>                         setbflag(6);
>>>                 }
>>>                 save("location");
>>>                 exit;
>>>         };
>>>
>>>         exit;
>>> }
>>>
>>> route[1] {
>>>         log("--------------------- Stateful Reply\n");
>>>         if (!t_relay()) {
>>>                 sl_reply_error();
>>>         };
>>>         exit;
>>> }
>>> ------------------- END openser.cfg
>>>
>>> Here is my Simple Perl
>>>
>>>
>>> ------------------- BEGIN net-sip.pl
>>> use OpenSER qw ( log );
>>> use OpenSER::Constants;
>>> use Net::SIP;
>>>
>>> # Predefined body, not querying db yet
>>> my $body = '"Franky Chang" sip:101 at 192.168.0.1;user=phone
>>> "Steven Jones" sip:102 at 192.168.0.1;user=phone
>>> "Marie Sun" sip:103 at 192.168.0.1;user=phone
>>> ';
>>>
>>>
>>> sub numberguessing {
>>>         my $m = shift;
>>>         my $pkt = Net::SIP::Request->new( $m->getMessage() );
>>>         my $resp = $pkt->create_response(200, "OK");
>>>         $resp->set_body($body);
>>>         $resp->add_header('Content-Type','application/number-guessing');
>>>
>>>         my $leg = Net::SIP::Leg->new(
>>>             addr => '111.222.333.444', port => '5061');
>>>
>>>         $leg->deliver( $resp, '111.222.333.444:5060' );
>>>
>>>         # 111.222.333.444 is the IP of OpenSER
>>>         # I'm sending from port 5061 to port 5060
>>>
>>>         return 1;
>>> }
>>> ------------------- END net-sip.pl
>>>
>>> OpenSER in verbose debugging module says that it cannot find a 
>>> matching transaction for the 200 OK reply (probably because is 
>>> originated from port 5061 and it has never forwarded it to that port ? )
>>>
>>> Here is OpenSER DEBUG log:
>>>
>>>  0(24828) SIP Reply  (status):
>>>  0(24828)  version: <SIP/2.0>
>>>  0(24828)  status:  <200>
>>>  0(24828)  reason:  <OK>
>>>  0(24828) parse_headers: flags=2
>>>  0(24828) get_hdr_field: cseq <cseq>: <1> <PUBLISH>
>>>  0(24828) DEBUG:parse_to:end of header reached, state=10
>>>  0(24828) DBUG:parse_to: display={"Edoardo"}, 
>>> ruri={sip:eserra at 111.222.333.444}
>>>  0(24828) DEBUG: get_hdr_field: <to> [43]; 
>>> uri=[sip:eserra at 111.222.333.444]
>>>  0(24828) DEBUG: to body ["Edoardo" <sip:eserra at 111.222.333.444>
>>> ]
>>>  0(24828) Found param type 232, <branch> = <z9hG4bK-m3j054b6d8q6>; 
>>> state=6
>>>  0(24828) Found param type 235, <rport> = <n/a>; state=17
>>>  0(24828) end of header reached, state=5
>>>  0(24828) parse_headers: Via found, flags=2
>>>  0(24828) parse_headers: this is the first via
>>>  0(24828) After parse_msg...
>>>  0(24828) DEBUG:forward_reply: found module tm, passing reply to it
>>>  0(24828) DEBUG: t_check: start=0xffffffff
>>>  0(24828) parse_headers: flags=22
>>>  0(24828) DEBUG: t_reply_matching: failure to match a transaction
>>>  0(24828) DEBUG: t_check: end=(nil)
>>>  0(24828) parse_headers: flags=4
>>>  0(24828) DEBUG: get_hdr_body : content_length=135
>>>  0(24828) found end of header
>>>  0(24828) ERROR:forward_reply: no 2nd via found in reply
>>>  0(24828) DEBUG:destroy_avp_list: destroying list (nil)
>>>  0(24828) receive_msg: cleaning up
>>>
>>> Here is also the tshark dump of the 2 packets (PUBLISH and its reply)
>>>
>>> Request-Line: PUBLISH sip:eserra at 213.92.23.108 SIP/2.0
>>> Message Header
>>>     Via: SIP/2.0/UDP 
>>> 192.168.254.151:2051;branch=z9hG4bK-ma9r5n0t4jfq;rport
>>>     From: "Edoardo" <sip:eserra at 111.222.333.444>;tag=39wlni6ex1
>>>     To: "Edoardo" <sip:eserra at 111.222.333.444>
>>>     Call-ID: 3c27c039249b-jml9w7t9sywx
>>>     CSeq: 1 PUBLISH
>>>     Max-Forwards: 70
>>>     Event: number-guessing
>>>     Content-Type: application/text
>>>     Content-Length: 25
>>> Message body
>>>     Number: 10\r\n
>>>     Max-Hits: 3\r\n
>>>
>>>
>>> Status-Line: SIP/2.0 200 OK
>>> Message Header
>>>     call-id: 3c27c0daa600-emnlo1xcejtn
>>>     cseq: 1 PUBLISH
>>>     from: "Edoardo" <sip:eserra at 111.222.333.444>;tag=6c1y8pp3fb
>>>     to: "Edoardo" <sip:eserra at 111.222.333.444>
>>>     via: SIP/2.0/UDP 
>>> 192.168.254.151:2051;branch=z9hG4bK-623oddiyzg56;rport
>>>     content-type: application/number-guessing
>>>     Content-Length: 135
>>> Message body
>>>     "Franky Chang" sip:101 at 192.168.0.1;user=phone\n
>>>     "Steven Jones" sip:102 at 192.168.0.1;user=phone\n
>>>     "Marie Sun" sip:103 at 192.168.0.1;user=phone\n
>>>
>>> Hope this info is enough for a debug :)
>>>
>>> Tnx in advance
>>>
>>> Regards
>>>
>>> Edoardo Serra
>>> EXSORSA LLC
>>>
>>>
>>> _______________________________________________
>>> Users mailing list
>>> Users at openser.org
>>> http://openser.org/cgi-bin/mailman/listinfo/users
>>
> 
> 
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