[Freeswitch-users] mod_xml_curl - missing dialplan variable (domain of originating user for blind transfer)

[Cal Leeming [Simplicity Media Ltd]]

Another quick update on this before I pass out from lack of sleep..!

Just had a look through the mod_sofia.c/h source and found the following;

mod_sofia.c/mod_sofia.h
#define SOFIA_REFER_TO_VARIABLE "sip_refer_to"
if (!zstr(full_ref_by)) {
switch_channel_set_variable(t_channel, SOFIA_SIP_HEADER_PREFIX
"Referred-By", full_ref_by);
}
if (!zstr(full_ref_to)) {
switch_channel_set_variable(t_channel, SOFIA_REFER_TO_VARIABLE,
full_ref_to);
}
if (!zstr(full_ref_to)) {
switch_channel_set_variable(t_channel, SOFIA_REFER_TO_VARIABLE,
full_ref_to);
}
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG,
"Process REFER to [%s@%s]\n", exten, (char *) refer_to->r_url->url_host);

If the correct approach is deemed to be patching code, then I figured it
could be as simple as this;

switch_channel_set_variable(t_channel, "Referred-By-User", exten);
switch_channel_set_variable(t_channel, "Referred-By-Domain", (char *)
refer_to->r_url->url_host);

This is pretty much where my knowledge of C ends, I can (just about) read
and copy chunks of C code, but that's about it :)

Cal

On Mon, Nov 19, 2012 at 4:38 AM, Cal Leeming [Simplicity Media Ltd] <
cal.leeming at simplicitymedialtd.co.uk> wrote:

> Not sure if this is relevant but thought I'd point it out.
>
> The following field seems to contain the IP of the domain we were
> expecting ('c1881.voiceflare.co.uk')
>
>  u'variable_sip_from_host': u'89.238.182.137',
>
> Normally, this field would contain the hostname and not the IP.
>
> Cal
>
> On Mon, Nov 19, 2012 at 4:34 AM, Cal Leeming [Simplicity Media Ltd] <
> cal.leeming at simplicitymedialtd.co.uk> wrote:
>
>> Hi guys,
>>
>> In a nut shell, it appears that when attempting to perform a blind
>> transfer under certain conditions (explained below), mod_xml_curl does not
>> expose the originating domain in a clean format.
>>
>> My initial plan was to find the point where these variable were being
>> generated, look at what was available, then add an extra variable for the
>> domain and submit a patch.
>>
>> Sadly my C isn't great and I hit a brick wall, so if anyone can help out,
>> I will ensure the mod_xml_curl documentation is updated and/or assist with
>> any patching/testing required.
>>
>>  Please take the following scenario;
>>
>> * Extension 2000 calls an external number via a gateway (i.e. bridge
>> sofia/gateway/name/e164_number_here).
>> * Call connects fine, audio stays good, no disconnection problems etc.
>> * Call is blind transferred to another extension
>>
>> As a result, the following is determined;
>>
>> * User initiating the blind transfer is 2000
>> * Domain initiating the blind transfer is c1881.voiceflare.co.uk
>> * Destination number of the call is 447866123456
>> * Number to blind transfer to is 2001
>> * Call to mod_xml_curl is made
>>
>> It makes reference to the User in the following 'clean' variables (by
>> clean, I mean variables that just contain 2000 and don't require mangling
>> to extract the info);
>>
>>  u'Caller-ANI': u'2000',
>>  u'Caller-Username': u'2000',
>>  u'Caller-Caller-ID-Number': u'2000',
>>  u'Hunt-ANI': u'2000',
>>  u'Hunt-Caller-ID-Number': u'2000',
>>  u'Hunt-Username': u'2000',
>>  u'variable_last_sent_callee_id_number': u'2000',
>>  u'variable_sip_from_user': u'2000',
>>
>> It also has the User in the following unclean variables;
>>
>>  u'variable_bridge_channel': u'sofia/external/
>> 2000 at c1881.voiceflare.co.uk:5060',
>>  u'variable_sip_from_uri': u'2000 at 89.238.182.137',
>>  u'variable_sip_full_from': u'"foxx" <sip:2000 at 89.238.182.137
>> >;tag=XryjFQp3rB2NF',
>>  u'variable_sip_h_Referred-By': u'"foxx" <
>> sip:2000 at c1881.voiceflare.co.uk:5060>',
>>
>> However, it only references the domain in the following unclean variables;
>>
>>  u'variable_bridge_channel': u'sofia/external/
>> 2000 at c1881.voiceflare.co.uk:5060',
>>  u'variable_sip_h_Referred-By': u'"foxx" <
>> sip:2000 at c1881.voiceflare.co.uk:5060>',
>>  u'variable_sip_refer_to': u'<sip:2001 at c1881.voiceflare.co.uk:5060>',
>>
>> Lets say that we want to determine the user/domain that has initiated
>> this transfer, doing so would mean mangling with one of those above
>> variables, which seems a bit dirty (plus it is not clear which is the
>> correct one to use).
>>
>> I have attached the SIP trace of the entire blind transfer event, and the
>> full mod_xml_curl request being sent.
>>
>> If anyone could answer the following, it'd be much appreciated;
>>
>> * Should there be an improvement patch that exposes the domain of the
>> user that originated the blind transfer?
>> * Are there better/alternative ways to extracting the domain of the user
>> that originated the blind transfer?
>>
>> Many thanks
>>
>> Cal
>>
>>
>
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