Re: [asterisk-users] Get channel variables via ARI/AMI

[Jeff LaCoursiere]

I need to get hooked up with this class, I could have students doing 
projects for homework :) Interested in RTCP?


j

On 6/26/23 7:45 PM, TTT wrote:


I’m in training, so I have to demonstrate something SIP related.  I 
figure it would be cool to hack a call, hanging it up while in 
progress from outside Asterisk.  Doing so will demonstrate 
use/knowledge of ARI, AMI, SIP, route-sets, UDP, etc.


Practical value: *zero*

J

Who knows, maybe this will have an actual application for someone 
someday.  In practical terms I think building a proxy would be the 
right way to manipulate the SIP for a call in progress, but that 
sounds like a huge project.  I’ve got to demonstrate something by end 
of week.


*From:*asterisk-users [mailto:asterisk-users-boun...@lists.digium.com] 
*On Behalf Of *Jeff LaCoursiere

*Sent:* Monday, June 26, 2023 6:20 PM
*To:* asterisk-users@lists.digium.com
*Subject:* Re: [asterisk-users] Get channel variables via ARI/AMI

On 6/26/23 9:00 AM, Joshua C. Colp wrote:

On Mon, Jun 26, 2023 at 10:57 AM TTT  wrote:

I am connecting to the ARI with subscribe all, so I can see
channels being created.  I now want to extract a variety of
header variables (at the moment the from and to tag).  I tried
to read them from the ARI but Asterisk refuses since the
channel is not in a  stasis app.

Is there a way to read these from either the ARI or AMI ?  I’m
trying not to modify the dialplan.

ARI, No.

AMI, Yes[1].

[1]
https://wiki.asterisk.org/wiki/display/AST/Asterisk+20+ManagerAction_Getvar

I'm curious what the actual application is here - you want to connect 
to AMI to pull information that you will use to pretend to be a leg, 
just to send "BYE", when you could just hangup the leg with AMI (or do 
just about anything else you might think of).  Sometimes it is better 
to fully explain what you are trying to accomplish, and some folks 
here can try to steer you towards a workable solution.  It almost 
sounds... nefarious.


Cheers,

--
Jeff LaCoursiere
StratusTalk, Inc.
703 496 4990 x108
815 546 6599 cell



--
Jeff LaCoursiere
StratusTalk, Inc.
703 496 4990 x108
815 546 6599 cell
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Re: [asterisk-users] Get channel variables via ARI/AMI

[TTT]

And I have to admit, I have learned a lot just investigating this.  (And 
appreciate the advice)

 

From: asterisk-users [mailto:asterisk-users-boun...@lists.digium.com] On Behalf 
Of Jeff LaCoursiere
Sent: Monday, June 26, 2023 6:22 PM
To: asterisk-users@lists.digium.com
Subject: Re: [asterisk-users] Get channel variables via ARI/AMI

 

On 6/26/23 5:19 PM, Jeff LaCoursiere wrote:

On 6/26/23 9:00 AM, Joshua C. Colp wrote:

On Mon, Jun 26, 2023 at 10:57 AM TTT mailto:li...@telium.io> 
> wrote:

I am connecting to the ARI with subscribe all, so I can see channels being 
created.  I now want to extract a variety of header variables (at the moment 
the from and to tag).  I tried to read them from the ARI but Asterisk refuses 
since the channel is not in a  stasis app.

 

Is there a way to read these from either the ARI or AMI ?  I’m trying not to 
modify the dialplan.

 

ARI, No.

AMI, Yes[1]. 

 

[1] https://wiki.asterisk.org/wiki/display/AST/Asterisk+20+ManagerAction_Getvar


 

I'm curious what the actual application is here - you want to connect to AMI to 
pull information that you will use to pretend to be a leg, just to send "BYE", 
when you could just hangup the leg with AMI (or do just about anything else you 
might think of).  Sometimes it is better to fully explain what you are trying 
to accomplish, and some folks here can try to steer you towards a workable 
solution.  It almost sounds... nefarious.

Meant that towards TTT, not Josh, in case that wasn't clear.



-- 
Jeff LaCoursiere
StratusTalk, Inc.
703 496 4990 x108
815 546 6599 cell
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Re: [asterisk-users] Get channel variables via ARI/AMI

[TTT]

I’m in training, so I have to demonstrate something SIP related.  I figure it 
would be cool to hack a call, hanging it up while in progress from outside 
Asterisk.  Doing so will demonstrate use/knowledge of ARI, AMI, SIP, 
route-sets, UDP, etc.

 

Practical value: zero

 

:)

 

Who knows, maybe this will have an actual application for someone someday.  In 
practical terms I think building a proxy would be the right way to manipulate 
the SIP for a call in progress, but that sounds like a huge project.  I’ve got 
to demonstrate something by end of week.

 

From: asterisk-users [mailto:asterisk-users-boun...@lists.digium.com] On Behalf 
Of Jeff LaCoursiere
Sent: Monday, June 26, 2023 6:20 PM
To: asterisk-users@lists.digium.com
Subject: Re: [asterisk-users] Get channel variables via ARI/AMI

 

On 6/26/23 9:00 AM, Joshua C. Colp wrote:

On Mon, Jun 26, 2023 at 10:57 AM TTT mailto:li...@telium.io> 
> wrote:

I am connecting to the ARI with subscribe all, so I can see channels being 
created.  I now want to extract a variety of header variables (at the moment 
the from and to tag).  I tried to read them from the ARI but Asterisk refuses 
since the channel is not in a  stasis app.

 

Is there a way to read these from either the ARI or AMI ?  I’m trying not to 
modify the dialplan.

 

ARI, No.

AMI, Yes[1]. 

 

[1] https://wiki.asterisk.org/wiki/display/AST/Asterisk+20+ManagerAction_Getvar


 

I'm curious what the actual application is here - you want to connect to AMI to 
pull information that you will use to pretend to be a leg, just to send "BYE", 
when you could just hangup the leg with AMI (or do just about anything else you 
might think of).  Sometimes it is better to fully explain what you are trying 
to accomplish, and some folks here can try to steer you towards a workable 
solution.  It almost sounds... nefarious.

Cheers,

-- 
Jeff LaCoursiere
StratusTalk, Inc.
703 496 4990 x108
815 546 6599 cell
-- 
_
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Re: [asterisk-users] Get channel variables via ARI/AMI

[Jeff LaCoursiere]

On 6/26/23 5:19 PM, Jeff LaCoursiere wrote:

On 6/26/23 9:00 AM, Joshua C. Colp wrote:

On Mon, Jun 26, 2023 at 10:57 AM TTT  wrote:

I am connecting to the ARI with subscribe all, so I can see
channels being created.  I now want to extract a variety of
header variables (at the moment the from and to tag).  I tried to
read them from the ARI but Asterisk refuses since the channel is
not in a  stasis app.

Is there a way to read these from either the ARI or AMI ?  I’m
trying not to modify the dialplan.


ARI, No.
AMI, Yes[1].

[1] 
https://wiki.asterisk.org/wiki/display/AST/Asterisk+20+ManagerAction_Getvar


I'm curious what the actual application is here - you want to connect 
to AMI to pull information that you will use to pretend to be a leg, 
just to send "BYE", when you could just hangup the leg with AMI (or do 
just about anything else you might think of).  Sometimes it is better 
to fully explain what you are trying to accomplish, and some folks 
here can try to steer you towards a workable solution.  It almost 
sounds... nefarious.



Meant that towards TTT, not Josh, in case that wasn't clear.

--
Jeff LaCoursiere
StratusTalk, Inc.
703 496 4990 x108
815 546 6599 cell
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Re: [asterisk-users] Get channel variables via ARI/AMI

[Jeff LaCoursiere]

On 6/26/23 9:00 AM, Joshua C. Colp wrote:

On Mon, Jun 26, 2023 at 10:57 AM TTT  wrote:

I am connecting to the ARI with subscribe all, so I can see
channels being created. I now want to extract a variety of header
variables (at the moment the from and to tag).  I tried to read
them from the ARI but Asterisk refuses since the channel is not in
a  stasis app.

Is there a way to read these from either the ARI or AMI ?  I’m
trying not to modify the dialplan.


ARI, No.
AMI, Yes[1].

[1] 
https://wiki.asterisk.org/wiki/display/AST/Asterisk+20+ManagerAction_Getvar


I'm curious what the actual application is here - you want to connect to 
AMI to pull information that you will use to pretend to be a leg, just 
to send "BYE", when you could just hangup the leg with AMI (or do just 
about anything else you might think of). Sometimes it is better to fully 
explain what you are trying to accomplish, and some folks here can try 
to steer you towards a workable solution.  It almost sounds... nefarious.


Cheers,

--
Jeff LaCoursiere
StratusTalk, Inc.
703 496 4990 x108
815 546 6599 cell
-- 
_
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Re: [asterisk-users] Get channel variables via ARI/AMI

[TTT]

According to RFC3261 :

 

It is possible for the CSeq sequence number to be higher than the remote 
sequence number by more than one. This is not an error condition, and a UAS 
SHOULD be prepared to receive and process requests with CSeq values more than 
one higher than the previous received request.

 

So if I use a high value integer (maxint) I’m hoping the UAC will accept my 
message (though this will mess up future transactions, so other than BYE this 
is not a viable solution for an ongoing dialog).  The other problem I see is 
that I can't get the route set, so this this would work only with UAC’s on the 
same network (not NAT/proxies/etc).   If I needed to traverse NAT I would need 
something like Kamilio as Eric points out, to get the route set).  Or…maybe 
PJSIP_HEADERS will give me the route set..I need to experiment with that one).

 

Since this is just for my learning, I want to see if I can hangup a call in 
progress, running through the asterisk server.  This is fun for my learning, so 
I realize there is of little practical value :)

 

Brian

 

 

From: asterisk-users [mailto:asterisk-users-boun...@lists.digium.com] On Behalf 
Of Joshua C. Colp
Sent: Monday, June 26, 2023 3:56 PM
To: Asterisk Users Mailing List - Non-Commercial Discussion 

Subject: Re: [asterisk-users] Get channel variables via ARI/AMI

 

On Mon, Jun 26, 2023 at 4:35 PM TTT mailto:li...@telium.io> > 
wrote:

I think that’s getting me close.  I’m trying to get (or recreate) the FROM and 
TO lines of the header, from a system running PJSIP.  I think if I use CHANNEL 
to get local_uri and local_tag I can recreate a FROM line like:

FROM=;tag=TAG

 

And if I use CHANNEL to get remote_uri and remote_tag I can recreate a FROM 
line like:

TO=;tag=TAG

 

Would it be correct to assume that with this info (and ip:port info) I should 
be able to send a UDP SIP message from the PBX to the UA which appears to be 
part of the current call dialog?  I realize this is an odd thing to do, but I’m 
just interested in technical feasibility at this point.  Before I try to code 
this I want to ensure I’m not missing something stupid.

 

Probably not. Sequence number also matters.

 

-- 

Joshua C. Colp

Asterisk Project Lead

Sangoma Technologies

Check us out at www.sangoma.com   and www.asterisk.org 
 

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_
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Re: [asterisk-users] Get channel variables via ARI/AMI

[Eric Wieling]

If you want to do more than just get headers from the INVITE, then 
you'll need to use an actual SIP Proxy like Kamailio.


On 6/26/23 15:03, TTT wrote:
It looks like if I call Getvar and pass PJSIP_HEADERS() I can get the 
entire SIP header for a channel.  I also read (on stackoverflow) that 
the PJSIP_HEADER function will only return the headers from the INVITE 
of the _inbound_ channel.


If that’s correct, how would I get the headers from the outbound channel 
(second leg of the bridged call) INVITE ?  Or will PJSIP_HEADERS() in 
fact return the header from either inbound out outbound legs?


Thanks

Brian

*From:*asterisk-users [mailto:asterisk-users-boun...@lists.digium.com] 
*On Behalf Of *Joshua C. Colp

*Sent:* Monday, June 26, 2023 10:00 AM
*To:* Asterisk Users Mailing List - Non-Commercial Discussion 


*Subject:* Re: [asterisk-users] Get channel variables via ARI/AMI

On Mon, Jun 26, 2023 at 10:57 AM TTT > wrote:


I am connecting to the ARI with subscribe all, so I can see channels
being created.  I now want to extract a variety of header variables
(at the moment the from and to tag).  I tried to read them from the
ARI but Asterisk refuses since the channel is not in a  stasis app.

Is there a way to read these from either the ARI or AMI ?  I’m
trying not to modify the dialplan.

ARI, No.

AMI, Yes[1].

[1] 
https://wiki.asterisk.org/wiki/display/AST/Asterisk+20+ManagerAction_Getvar 


--

Joshua C. Colp

Asterisk Project Lead

Sangoma Technologies

Check us out at www.sangoma.com  and 
www.asterisk.org 





--
http://help.nyigc.net/

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Re: [asterisk-users] Get channel variables via ARI/AMI

[Joshua C. Colp]

On Mon, Jun 26, 2023 at 4:35 PM TTT  wrote:

> I think that’s getting me close.  I’m trying to get (or recreate) the FROM
> and TO lines of the header, from a system running PJSIP.  I think if I use
> CHANNEL to get local_uri and local_tag I can recreate a FROM line like:
>
> *FROM=;tag=TAG*
>
>
>
> And if I use CHANNEL to get remote_uri and remote_tag I can recreate a
> FROM line like:
>
> *TO=;tag=TAG*
>
>
>
> Would it be correct to assume that with this info (and ip:port info) I
> should be able to send a UDP SIP message from the PBX to the UA which
> appears to be part of the current call dialog?  I realize this is an odd
> thing to do, but I’m just interested in technical feasibility at this
> point.  Before I try to code this I want to ensure I’m not missing
> something stupid.
>

Probably not. Sequence number also matters.

-- 
Joshua C. Colp
Asterisk Project Lead
Sangoma Technologies
Check us out at www.sangoma.com and www.asterisk.org
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_
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Re: [asterisk-users] Get channel variables via ARI/AMI

[TTT]

I think that’s getting me close.  I’m trying to get (or recreate) the FROM and 
TO lines of the header, from a system running PJSIP.  I think if I use CHANNEL 
to get local_uri and local_tag I can recreate a FROM line like:

FROM=;tag=TAG

 

And if I use CHANNEL to get remote_uri and remote_tag I can recreate a FROM 
line like:

TO=;tag=TAG

 

Would it be correct to assume that with this info (and ip:port info) I should 
be able to send a UDP SIP message from the PBX to the UA which appears to be 
part of the current call dialog?  I realize this is an odd thing to do, but I’m 
just interested in technical feasibility at this point.  Before I try to code 
this I want to ensure I’m not missing something stupid.

 

Thanks

Brian

 

 

From: asterisk-users [mailto:asterisk-users-boun...@lists.digium.com] On Behalf 
Of Joshua C. Colp
Sent: Monday, June 26, 2023 3:08 PM
To: Asterisk Users Mailing List - Non-Commercial Discussion 

Subject: Re: [asterisk-users] Get channel variables via ARI/AMI

 

On Mon, Jun 26, 2023 at 4:04 PM TTT mailto:li...@telium.io> > 
wrote:

It looks like if I call Getvar and pass PJSIP_HEADERS() I can get the entire 
SIP header for a channel.  I also read (on stackoverflow) that the PJSIP_HEADER 
function will only return the headers from the INVITE of the inbound channel.

 

If that’s correct, how would I get the headers from the outbound channel 
(second leg of the bridged call) INVITE ?  Or will PJSIP_HEADERS() in fact 
return the header from either inbound out outbound legs?

 

The answer is, you can't. There are SOME protocol level things accessible using 
CHANNEL[1] but that's it.

 

[1] https://wiki.asterisk.org/wiki/display/AST/Asterisk+20+Function_CHANNEL

 

-- 

Joshua C. Colp

Asterisk Project Lead

Sangoma Technologies

Check us out at www.sangoma.com   and www.asterisk.org 
 

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Re: [asterisk-users] Get channel variables via ARI/AMI

[Joshua C. Colp]

On Mon, Jun 26, 2023 at 4:04 PM TTT  wrote:

> It looks like if I call Getvar and pass PJSIP_HEADERS() I can get the
> entire SIP header for a channel.  I also read (on stackoverflow) that the
> PJSIP_HEADER function will only return the headers from the INVITE of the
> *inbound* channel.
>
>
>
> If that’s correct, how would I get the headers from the outbound channel
> (second leg of the bridged call) INVITE ?  Or will PJSIP_HEADERS() in fact
> return the header from either inbound out outbound legs?
>

The answer is, you can't. There are SOME protocol level things accessible
using CHANNEL[1] but that's it.

[1] https://wiki.asterisk.org/wiki/display/AST/Asterisk+20+Function_CHANNEL

-- 
Joshua C. Colp
Asterisk Project Lead
Sangoma Technologies
Check us out at www.sangoma.com and www.asterisk.org
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Re: [asterisk-users] Get channel variables via ARI/AMI

[TTT]

It looks like if I call Getvar and pass PJSIP_HEADERS() I can get the entire 
SIP header for a channel.  I also read (on stackoverflow) that the PJSIP_HEADER 
function will only return the headers from the INVITE of the inbound channel.

 

If that’s correct, how would I get the headers from the outbound channel 
(second leg of the bridged call) INVITE ?  Or will PJSIP_HEADERS() in fact 
return the header from either inbound out outbound legs?

 

Thanks

Brian

 

 

From: asterisk-users [mailto:asterisk-users-boun...@lists.digium.com] On Behalf 
Of Joshua C. Colp
Sent: Monday, June 26, 2023 10:00 AM
To: Asterisk Users Mailing List - Non-Commercial Discussion 

Subject: Re: [asterisk-users] Get channel variables via ARI/AMI

 

On Mon, Jun 26, 2023 at 10:57 AM TTT mailto:li...@telium.io> 
> wrote:

I am connecting to the ARI with subscribe all, so I can see channels being 
created.  I now want to extract a variety of header variables (at the moment 
the from and to tag).  I tried to read them from the ARI but Asterisk refuses 
since the channel is not in a  stasis app.

 

Is there a way to read these from either the ARI or AMI ?  I’m trying not to 
modify the dialplan.

 

ARI, No.

AMI, Yes[1]. 

 

[1] https://wiki.asterisk.org/wiki/display/AST/Asterisk+20+ManagerAction_Getvar


 

-- 

Joshua C. Colp

Asterisk Project Lead

Sangoma Technologies

Check us out at www.sangoma.com   and www.asterisk.org 
 

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_
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Re: [asterisk-users] Get channel variables via ARI/AMI

[Joshua C. Colp]

On Mon, Jun 26, 2023 at 10:57 AM TTT  wrote:

> I am connecting to the ARI with subscribe all, so I can see channels being
> created.  I now want to extract a variety of header variables (at the
> moment the from and to tag).  I tried to read them from the ARI but
> Asterisk refuses since the channel is not in a  stasis app.
>
>
>
> Is there a way to read these from either the ARI or AMI ?  I’m trying not
> to modify the dialplan.
>

ARI, No.
AMI, Yes[1].

[1]
https://wiki.asterisk.org/wiki/display/AST/Asterisk+20+ManagerAction_Getvar

-- 
Joshua C. Colp
Asterisk Project Lead
Sangoma Technologies
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[asterisk-users] Get channel variables via ARI/AMI

[TTT]

I am connecting to the ARI with subscribe all, so I can see channels being
created.  I now want to extract a variety of header variables (at the moment
the from and to tag).  I tried to read them from the ARI but Asterisk
refuses since the channel is not in a  stasis app.

 

Is there a way to read these from either the ARI or AMI ?  I'm trying not to
modify the dialplan.

 

Thanks

Brian

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