PJSIP_HEADER – Diversion Header Manipulation

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Asterisk Users 4 Comments

Hi all,

I’m trying to rewrite Diversion header when call forwarding is done on the phone. The phone sends “302 Moved Temporarily” response and sets Diversion header to a local number, but before Asterisk sends this call towards TSP provider I need to change Diversion header to a full PSTN
number. I am using PJSIP_HEADER in a pre-dial handler (configuration is below). On the same call I can add some other custom headers (logs are below).

Is there any chance I can rewrite Diversion header in this scenario with PJSIP_HEADER function? Asterisk version is 16.0.1 built from source on Debian 9.

Thank you

Davor

# Outgoing context – TSP provider
[outgoing]
exten =>
0123456789,1,Dial(PJSIP/${EXTEN}@${SBC_1},,b(add_diversion^FWDdiver^1))
same => n,Hangup()

# Diversion manipulation context
[add_diversion]
exten =>
FWDdiver,1,Set(PJSIP_HEADER(add,Diversion)=\;reason=unconditional\;screen=yes\;privacy=off))
exten =>
FWDdiver,2,Set(PJSIP_HEADER(add,CustomOne)=\;reason=unconditional\;screen=yes\;privacy=off))
exten =>
FWDdiver,3,Set(PJSIP_HEADER(add,CustomTwo)=\;reason=unconditional\;screen=yes\;privacy=off))
exten => FWDdiver,4,Return()

Asterisk*CLI>
— Now forwarding PJSIP/527-00000168 to ‘Local/0123456789@outgoing’
(thanks to PJSIP/836-00000169)
[Dec 10 10:25:08] NOTICE[26309][C-000000c0]: app_dial.c:1005 do_forward:
Not accepting call completion offers from call-forward recipient Local/0123456789@outgoing-0000002c;1
— Executing [0123456789@outgoing:1]
Dial(“Local/0123456789@outgoing-0000002c;2”,
“PJSIP/0123456789@SBC1,,b(add_diversion^FWDdiver^1)”) in new stack
— PJSIP/SBC1-0000016a Internal Gosub(add_diversion,FWDdiver,1) start
— Executing [FWDdiver@add_diversion:1] Set(“PJSIP/SBC1-0000016a”,
“PJSIP_HEADER(add,Diversion)=;reason=unconditional;screen=yes;privacy=off)”)
in new stack
— Executing [FWDdiver@add_diversion:2] Set(“PJSIP/SBC1-0000016a”,
“PJSIP_HEADER(add,CustomOne)=;reason=unconditional;screen=yes;privacy=off)”)
in new stack
— Executing [FWDdiver@add_diversion:3] Set(“PJSIP/SBC1-0000016a”,
“PJSIP_HEADER(add,CustomTwo)=;reason=unconditional;screen=yes;privacy=off)”)
in new stack
— Executing [FWDdiver@add_diversion:4]
Return(“PJSIP/SBC1-0000016a”, “”) in new stack

Phone => Asterisk U 10.201.8.192:5060 -> 10.201.1.19:5060
SIP/2.0 302 Moved Temporarily. Diversion: ;reason=unconditional.

Asterisk => TSP provider U 10.201.1.19:5060 -> 10.201.1.15:5060
CustomOne:
;reason=unconditional;screen=yes;privacy=off. CustomTwo:
;reason=unconditional;screen=yes;privacy=off. Diversion: ;reason=unconditional.

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4 thoughts on - PJSIP_HEADER – Diversion Header Manipulation

  • Davor,

    Have you attempted to do a Set(PJSIP_HEADER(remove,Diversion)=)) in your add_diversion context to remove the header Asterisk is passing through?

  • Hi John,

    yes I tried to do “remove” and “update” of the Diversion header but I
    get “No headers had been previously added to this session” error. As you can see from the configuration and logs below I can successfully add another From: header and make update to that additional From header.

    I previously missed to notice change in the domain part of SIP URI in Diversion header. Phone sets Diversion header to “836@10.201.1.19” and Asterisk makes change in domain part of Diversion hdr in INVITE message to “192.168.1.101”. This server has two network interfaces and
    192.168.1.101 is set on eth0. So, Asterisk makes a change to Diversion header but not the one set by PJSIP_HEADER function.

    Davor

    #1 Phone -> Asterisk U 10.201.8.192:5060 -> 10.201.1.19:5060
    SIP/2.0 302 Moved Temporarily. Diversion: ;reason=unconditional. Server: Linksys/SPA922-6.1.5(a). Content-Length: 0.

    #2 Asterisk -> TSP provider U 10.201.1.19:5060 -> 10.201.1.15:5060
    INVITE sip:0123456789@10.201.1.15:5060 SIP/2.0. From: ;tag=629ca252-0930-404b-9f58-f921ed264ebf. From: Update to From Header. Custom–

  • The Diversion header is created and managed by the implementation in PJSIP itself. It can’t be edited using the PJSIP_HEADER dialplan function, but can be manipulated using the normal core mechanisms[1].

    [1] https://wiki.asterisk.org/wiki/display/AST/Manipulating+Party+ID+Information#ManipulatingPartyIDInformation-REDIRECTINGdialplanfunction

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