[OpenSIPS-Devel] [OpenSIPS/opensips] 2adc11: Reworked ReINVITE and OPTIONS pinging

[Vlad Paiu]

  Branch: refs/heads/master
  Home:   https://github.com/OpenSIPS/opensips
  Commit: 2adc1140bc8c672f9831f8e2be8d488cf990cbda
      https://github.com/OpenSIPS/opensips/commit/2adc1140bc8c672f9831f8e2be8d488cf990cbda
  Author: Vlad Paiu <vladpaiu at opensips.org>
  Date:   2016-08-22 (Mon, 22 Aug 2016)

  Changed paths:
    M modules/dialog/dialog.c
    M modules/dialog/dlg_req_within.c
    M modules/dialog/dlg_req_within.h
    M modules/dialog/dlg_timer.c
    M modules/dialog/dlg_timer.h

  Log Message:
  -----------
  Reworked ReINVITE and OPTIONS pinging

Previous mechanism was going every X seconds through ALL dialogs that needed pinging
and would send ReINVITEs / OPTIONs out. In case there were many established dialogs
towards a specific destination / network, this would lead to flood protection
mechanisms getting triggered and calls getting bogusly ended.

Reworked the pinging mechanism so that it works more similar to the SIP session timers.
Each call will get pinged on fixed intervals based after the 200OK is received, based
on the configured options_ping_interval or reinvite_ping_interval parameters.