chan_sip: Honor Session-Expires in 200OK response when it's a RE-INVITE when asterisk...

RFC 4028 Section 7.2
 "UACs MUST be prepared to receive a Session-Expires header field in a
 response, even if none were present in the request."

What changed
  After ASTERISK-20787, inbound calls to asterisk with no Session-Expires in the INVITE are now are offered
  a Session-Expires (1800 asterisk default) in the response, with asterisk as the refresher.

Symptom:
  After 900 seconds (asterisk default refresher period 1800), asterisk RE-INVITEs the device, the device
   may respond with a much lower Session-Expires (180 in our case) value that it is now using.

  Asterisk ignores this response, as it's deemed both an INBOUND CALL, and a RE-INVITE.

  After 180 seconds the device times out and sends BYE (hangs up), asterisk is still working with the
  refresher period of 1800 as it ignored the 'Session Expires: 180' in the previous 200OK response.

Fix:
	handle_response_invite() when 200OK, remove check for outbound and reinvite.

(closes issue ASTERISK-21664)

Reported by: alecdavis
Tested by: alecdavis
alecdavis (license 585)

Review https://reviewboard.asterisk.org/r/2463/
........

Merged revisions 387312 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 387319 from http://svn.asterisk.org/svn/asterisk/branches/11

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@387327 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 2f8ad5a3e742877a817c9f19fd8b8aa0c04bc0ad..00a61e2fc788f0506b57df0dee86324b713a2c7b 100644 (file)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -23162,7 +23162,7 @@ static void handle_response_invite(struct sip_pvt *p, int resp, const char *rest
                }
 
                /* Check for Session-Timers related headers */
-               if (st_get_mode(p, 0) != SESSION_TIMER_MODE_REFUSE && p->outgoing_call == TRUE && !reinvite) {
+               if (st_get_mode(p, 0) != SESSION_TIMER_MODE_REFUSE) {
                        p_hdrval = (char*)sip_get_header(req, "Session-Expires");
                        if (!ast_strlen_zero(p_hdrval)) {
                                /* UAS supports Session-Timers */