Asterisk sip_header

[sipheader]
exten=>_x.,1,Noop(${SIP_HEADER(TO):5:3})
exten=>_x.,n,Noop(${SIP_HEADER(TO)})
same=>n,Noop(${SIP_HEADER(User-Agent)})
same=>n,Set(CALLERID(num)=${SIP_HEADER(Remote-Party-ID)})
same=>n,Set(pseudodid=${SIP_HEADER(TO)})
same=>n,Set(pseudodid=${CUT(pseudodid,@,1)})
same=>n,Noop(${pseudodid:5})

using diversion header


[sipheader]
exten=>s,1,Noop(${SIP_HEADER(TO):5:3})
exten=>s,n,Noop(${SIP_HEADER(TO)})
same=>n,Noop(${SIP_HEADER(User-Agent)})
same=>n,Set(pseudodid=${SIP_HEADER(Diversion)})
same=>n,Set(pseudodid=${CUT(pseudodid,@,1)})
same=>n,Noop(${pseudodid:5})
same=>n,Goto(from-trunk,${pseudodid:5},1)