chan_sip: Start session timer at 200, not at INVITE.

Asterisk started counting the session timer at INVITE while the other
end correctly started at 200. This meant that for short session-expiries
(90 seconds) combined with long ringing times (e.g. 30 seconds), asterisk
would wrongly assume that the timer was hit before the other end thought
it was time to send a session refresh. This resulted in prematurely
ended calls.

This changes the session timer to start counting first at 200 like RFC
says it should.

(Also removed a few excess NULL checks that would never hit, because if
they did, asterisk would have crashed already.)

ASTERISK-22551 #close
Reported by: i2045

Review: https://reviewboard.asterisk.org/r/3562/
........

Merged revisions 414620 from http://svn.asterisk.org/svn/asterisk/branches/1.8

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@414628 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index be1274b67fdd9a97b248b85468da487deff908c8..7a960922ddc76fdc063648dd95732cf7ad0ba9c6 100644 (file)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -7270,6 +7270,11 @@ static int sip_answer(struct ast_channel *ast)
                ast_rtp_instance_update_source(p->rtp);
                res = transmit_response_with_sdp(p, "200 OK", &p->initreq, XMIT_CRITICAL, oldsdp, TRUE);
                ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
+               /* RFC says the session timer starts counting on 200,
+                * not on INVITE. */
+               if (p->stimer->st_active == TRUE) {
+                       start_session_timer(p);
+               }
        }
        sip_pvt_unlock(p);
        return res;
@@ -25805,12 +25810,8 @@ static int handle_request_invite(struct sip_pvt *p, struct sip_request *req, str
        /* Check if OLI/ANI-II is present in From: */
        parse_oli(req, p->owner);
 
-       if (p->stimer->st_active == TRUE) {
-               if (reinvite == 0) {
-                       start_session_timer(p);
-               } else {
-                       restart_session_timer(p);
-               }
+       if (reinvite && p->stimer->st_active == TRUE) {
+               restart_session_timer(p);
        }
 
        if (!req->ignore && p)
@@ -26893,7 +26894,9 @@ static int handle_request_bye(struct sip_pvt *p, struct sip_request *req)
        }
 
        stop_media_flows(p); /* Immediately stop RTP, VRTP and UDPTL as applicable */
-       stop_session_timer(p); /* Stop Session-Timer */
+       if (p->stimer) {
+               stop_session_timer(p); /* Stop Session-Timer */
+       }
 
        if (!ast_strlen_zero(sip_get_header(req, "Also"))) {
                ast_log(LOG_NOTICE, "Client '%s' using deprecated BYE/Also transfer method.  Ask vendor to support REFER instead\n",
@@ -29196,11 +29199,6 @@ static void acl_change_event_cb(const struct ast_event *event, void *userdata)
 /*! \brief Session-Timers: Restart session timer */
 static void restart_session_timer(struct sip_pvt *p)
 {
-       if (!p->stimer) {
-               ast_log(LOG_WARNING, "Null stimer in restart_session_timer - %s\n", p->callid);
-               return;
-       }
-
        if (p->stimer->st_active == TRUE) {
                ast_debug(2, "Session timer stopped: %d - %s\n", p->stimer->st_schedid, p->callid);
                AST_SCHED_DEL_UNREF(sched, p->stimer->st_schedid,
@@ -29213,11 +29211,6 @@ static void restart_session_timer(struct sip_pvt *p)
 /*! \brief Session-Timers: Stop session timer */
 static void stop_session_timer(struct sip_pvt *p)
 {
-       if (!p->stimer) {
-               ast_log(LOG_WARNING, "Null stimer in stop_session_timer - %s\n", p->callid);
-               return;
-       }
-
        if (p->stimer->st_active == TRUE) {
                p->stimer->st_active = FALSE;
                ast_debug(2, "Session timer stopped: %d - %s\n", p->stimer->st_schedid, p->callid);
@@ -29232,11 +29225,6 @@ static void start_session_timer(struct sip_pvt *p)
 {
        unsigned int timeout_ms;
 
-       if (!p->stimer) {
-               ast_log(LOG_WARNING, "Null stimer in start_session_timer - %s\n", p->callid);
-               return;
-       }
-
        if (p->stimer->st_schedid > -1) {
                /* in the event a timer is already going, stop it */
                ast_debug(2, "Session timer stopped: %d - %s\n", p->stimer->st_schedid, p->callid);
@@ -29328,7 +29316,11 @@ return_unref:
                /* An error occurred.  Stop session timer processing */
                if (p->stimer) {
                        ast_debug(2, "Session timer stopped: %d - %s\n", p->stimer->st_schedid, p->callid);
+                       /* Don't pass go, don't collect $200.. we are the scheduled
+                        * callback. We can rip ourself out here. */
                        p->stimer->st_schedid = -1;
+                       /* Calling stop_session_timer is nice for consistent debug
+                        * logs. */
                        stop_session_timer(p);
                }