[Serusers] Call pickup

Dear all, i'm trying to have call pickup with SER (i use ser 0.9.6), i mean i'd like to have the capability to pick up a call that is directed to another user while the other user telephone is ringing. Is there someone that suceeded in this features? If it is not possible to get this feature by configuriation of ser (i mean using already present ser functions), is there someone that can suggest how to implemente such features? (for istance with external scripts,or with avpops, or using fifo, or writing a new ser module). Maybe the use of fifo could help, in particular i saw the ctd.sh example that is able to iniziate a call for two users using t_uac_dlg fifo function. I tryed to use t_uac_dlg to send a CANCEL to a transaction in progress (in the 180 ringing status) (taking by hand parameters like Call-ID, tag, branch etc.), but it seems that t_uac_dlg is not able to interact with the transaction in progress because it creates one different transaction. Is it real, or am i wrong? This is some log for this attempt: ################################################################ 1(17187) INFO: fifo_server: command empty 1(17187) fifo_get_method: method: 'CANCEL' 1(17187) DEBUG: fifo_get_ruri: 'sip:801@x.x.x' 1(17187) DEBUG: fifo_get_nexthop: next hop empty 1(17187) fifo_get_headers: headers: To: <sip:801@x.x.x> From: Stefano<sip:803@x.x.x>;tag=237abc61 Call-ID: 262a660822777d26 CSeq: 2 CANCEL 1(17187) parse_headers: flags=-1 1(17187) end of header reached, state=9 1(17187) DEBUG: get_hdr_field: <To> [28]; uri=[sip:801@x.x.x] 1(17187) DEBUG: to body [<sip:801@x.x.x> ] 1(17187) get_hdr_field: cseq <CSeq>: <2> <CANCEL> 1(17187) DEBUG: fifo_uac: parse_headers succeeded 1(17187) fifo_get_body: body: 1(17187) DEBUG: add_param: tag=237abc61 1(17187) end of header reached, state=29 1(17187) DEBUG: fifo_uac: EoL -- proceeding to transaction creation 1(17187) DEBUG:tm:t_uac: next_hop=<sip:801@x.x.x> 1(17187) DEBUG: mk_proxy: doing DNS lookup... 1(17187) get_record: lookup(_sip._udp.x.x.x, 33) failed 1(17187) sip_resolvehost: no SRV record found for x.x.x, trying 'normal' lookup... 1(17187) DEBUG:destroy_avp_list: destroying list (nil) 1(17187) DEBUG: dlg2hash: 55633 1(17187) DEBUG: add_to_tail_of_timer[4]: 0xb5ba0ac0 1(17187) DEBUG: add_to_tail_of_timer[0]: 0xb5ba0ad0 1(17187) **** done consume 2(17188) SIP Request: 2(17188) method: <CANCEL> 2(17188) uri: <sip:801@x.x.x> 2(17188) version: <SIP/2.0> 2(17188) parse_headers: flags=1 2(17188) Found param type 232, <branch> = <z9hG4bK159d.9169633.0>; state=16 2(17188) end of header reached, state=5 2(17188) parse_headers: Via found, flags=1 2(17188) parse_headers: this is the first via 2(17188) After parse_msg... 2(17188) preparing to run routing scripts... 2(17188) parse_headers: flags=128 2(17188) end of header reached, state=9 2(17188) DEBUG: get_hdr_field: <To> [28]; uri=[sip:801@x.x.x] 2(17188) DEBUG: to body [<sip:801@x.x.x> ] 2(17188) get_hdr_field: cseq <CSeq>: <2> <CANCEL> 2(17188) DEBUG: get_hdr_body : content_length=0 2(17188) found end of header 2(17188) DEBUG: is_maxfwd_present: max_forwards header not found! 2(17188) DEBUG: add_param: tag=237abc61 2(17188) end of header reached, state=29 2(17188) parse_headers: flags=256 2(17188) find_first_route: No Route headers found 2(17188) loose_route: There is no Route HF 2(17188) is_local(): Realm 'x.x.x' is local 2(17188) DEBUG: t_newtran: msg id=9 , global msg id=8 , T on entrance=0xffffffff 2(17188) parse_headers: flags=-1 2(17188) parse_headers: flags=60 2(17188) t_lookup_request: start searching: hash=55633, isACK=0 2(17188) DEBUG: RFC3261 transaction matching failed 2(17188) DEBUG: t_lookup_request: no transaction found 2(17188) DBG: trans=0xb5ba1488, callback type 1, id 0 entered 2(17188) parse_headers: flags=44 2(17188) DEBUG: t_lookupOriginalT: searching on hash entry 55633 2(17188) DEBUG: RFC3261 transaction matching failed 2(17188) DEBUG: t_lookupOriginalT: no CANCEL matching found! 2(17188) DEBUG: t_lookupOriginalT completed 2(17188) DEBUG: mk_proxy: doing DNS lookup... 2(17188) get_record: lookup(_sip._udp.x.x.x, 33) failed 2(17188) sip_resolvehost: no SRV record found for x.x.x, trying 'normal' lookup... 2(17188) check_via_address(x.x.x.x, x.x.x.x, 0) ################################################################ Another thing, i saw that t_uac_cancel, instead, is able to interact with an existing transaction, by sending CANCEL to called and 487 to caller (using t_lookup_callid function to get transaction from callid and cseq). Does someone think that it is possible to modify t_uac_cancel to handle basic pickup functions? (that should be CANCEL for the called side and redirect for caller towards pickup user) This is some log for this case: ################################################################## 1(16115) INFO: fifo_server: command empty 1(16115) DEBUG: fifo_uac_cancel: ############### begin ############## 1(16115) DEBUG: fifo_uac_cancel: callid="0b29c5266716aa67" 1(16115) DEBUG: fifo_uac_cancel: cseq="2" 1(16115) created comparable call_id header field: >Call-ID: 0b29c5266716aa67 < 1(16115) created comparable cseq header field: >CSeq: 2 INVITE< 1(16115) just locked hash index 37328, looking for transactions there: 1(16115) we have a match: callid=>>Call-ID: 0b29c5266716aa67 << cseq=>>CSeq: 2<< 1(16115) DEBUG: t_lookup_callid: transaction found. 1(16115) DEBUG: fifo_uac_cancel: now calling cancel_uacs 1(16115) DEBUG: cancel_branch: sending cancel... 1(16115) DEBUG: add_to_tail_of_timer[4]: 0xb5b763f0 1(16115) DEBUG: add_to_tail_of_timer[0]: 0xb5b76400 1(16115) DEBUG: fifo_uac_cancel: ################ end ############## ################################################################## Thank you very much for your help Stefano Blasco