Freeswitch sets the maximum call duration

 

summary

freeswitch As open source VOIP Soft switch , Yes, after fs Every phone call should have enough control .

In a telephone call , Call duration is an important data , In the actual use process of the customer , There will be various scenario requirements for call duration .

Discussion in this document fs How to set the maximum call duration , And analyze from the perspective of source code fs Implementation principle of .

Environmental Science

centos：CentOS  release 7.0 (Final) Or above

freeswitch：v1.8.7

GCC：4.8.5

Hang up regularly

freeswitch Provides APP Interface “sched_hangup”, Help users to realize the function of hanging up regularly , To meet the requirement of setting the maximum call duration .

The method is simple to use , according to fs Official documents of , The call format is as follows .

// Call format in dial plan

<action application="sched_hangup" data="[+]<time>[ <hangup_cause>]"/>

// As API Interface call format

sched_hangup [+]<time> <uuid>[ <hangup_cause>]"

// example ,C++ Code

// Set the maximum call duration , Default 55 second

ptmp = switch_core_get_variable("max_duration");

max_duration = (ptmp? ptmp: "+55");

if (SWITCH_STATUS_SUCCESS != switch_core_session_execute_application(session, "sched_hangup", max_duration))

{

switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_WARNING,

                "sched_hangup failed, max_duration = %s\n", max_duration);

}

// example , Dial plan

<action application="sched_hangup" data="+55 allotted_timeout"/>

<action application="sched_hangup" data="+55"/>

<action application="sched_hangup" data="55"/>

In the dial plan example above , The parameters of the three call methods are different , But the actual test results are the same .

This is different from the official interface document .

Time in seconds.

If used with + then the call will be hung up after that number of seconds.

If used without + then the given value is considered the number of seconds since the epoch, 1970-01-01 00:00:00 UTC

Interface description ,“sched_hangup +55” and “sched_hangup 55” The results should be different .

Let's look in the source code to see what special processing has been done .

Source code

sched_hangup The interface code is in mod_dptools modular , The logic is simple , Processing parameters , call “switch_ivr_schedule_hangup” Interface .

In the process of processing parameters , For parameters 1 in “+” Processing of number , The code is as follows
int sec = atol(argv[0] + 1);

if (*argv[0] == '+') {

        when = switch_epoch_time_now(NULL) + sec;

} else {

       when = atol(argv[0]);

}

// After processing ,when The value of is ”now+55” and “55”

switch_ivr_schedule_hangup The interface code is in “switch_ivr_async.c” in , Interface “switch_scheduler_add_task” Created a scheduled task , The logic of a scheduled task is to hang up a specified call .

In the above logic , There is no special processing involving execution time , only “switch_scheduler_add_task” Create a task interface , This interface is described in the previous article “freeswitch Task engine implementation analysis ” There is a detailed introduction to .

//switch_scheduler_add_task, Special handling of task execution time , Less than now be +now

if (task_runtime < now) {

       container->task.repeat = (uint32_t)task_runtime;

       task_runtime += now;

}

After that , above “sched_hangup” in call “+55” and “55” The results of the two parameters are unified .

summary

freeswitch There are many practical functions and code flow in the function interface part of , Suitable for fs Development reference for in-depth customization requirements .

Finally, put a sketch , Easy to understand . The data structure and processing of scheduled tasks are actually more complex than this .

 

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