media_exchange: keep media session until dlg ends

This fixes situation when a media session is both started and ended from
different (MI) processes.

modules/media_exchange/media_sessions.c

@@ -23,14 +23,29 @@
 
 static int media_session_dlg_idx;
 
-void media_session_unref(void *param)
+#define MEDIA_SESSION_DETACHED(ms) (ms->dlg == NULL)
+#define MEDIA_SESSION_HAS_LEGS(ms) (ms->legs != NULL)
+
+static void media_session_detach(struct media_session *ms)
+{
+ if (MEDIA_SESSION_DETACHED(ms))
+ return;
+ media_dlg.dlg_ctx_put_ptr(ms->dlg, media_session_dlg_idx, NULL);
+ media_dlg.dlg_unref(ms->dlg, 1);
+ ms->dlg = NULL;
+}
+
+static void media_session_unref(void *param)
 {
  struct media_session *ms = (struct media_session *)param;
  MEDIA_SESSION_LOCK(ms);
- if (ms->legs)
+ media_session_detach(ms);
+ if (MEDIA_SESSION_HAS_LEGS(ms)) {
  LM_WARN("media session %p still in use %p!\n", ms, ms->legs);
- else
+ MEDIA_SESSION_UNLOCK(ms);
+ } else {
  media_session_release(ms, 1);
+ }
 }
 
 int init_media_sessions(void)
@@ -88,24 +103,21 @@ void media_session_leg_free(struct media_session_leg *msl)
 
 void media_session_release(struct media_session *ms, int unlock)
 {
- int existing_legs = (ms->legs != NULL);
+ int existing_legs = MEDIA_SESSION_HAS_LEGS(ms);
 
  if (unlock)
  MEDIA_SESSION_UNLOCK(ms);
  if (existing_legs) {
  LM_DBG("media session %p has onhoing legs!\n", ms);
  return;
  }
- media_session_free(ms);
+ /* release only if detached from the dialog */
+ if (MEDIA_SESSION_DETACHED(ms))
+ media_session_free(ms);
 }
 
 void media_session_free(struct media_session *ms)
 {
-
- if (ms->dlg) {
- media_dlg.dlg_ctx_put_ptr(ms->dlg, media_session_dlg_idx, NULL);
- media_dlg.dlg_unref(ms->dlg, 1);
- }
  lock_destroy(&ms->lock);
  LM_DBG("releasing media_session=%p\n", ms);
  shm_free(ms);
@@ -126,6 +138,7 @@ static void media_session_dlg_end(struct dlg_cell *dlg, int type, struct dlg_cb_
  return;
 
  media_session_end(ms, MEDIA_LEG_BOTH, 0, 0);
+ media_session_unref(ms);
 }
 
 struct media_session *media_session_create(struct dlg_cell *dlg)
@@ -149,6 +162,7 @@ struct media_session *media_session_create(struct dlg_cell *dlg)
  /* we are not storing media session in the dialog, as it might
  * dissapear along the way, if the playback ends */
  LM_ERR("could not register media_session_termination!\n");
+ media_session_detach(ms);
  media_session_free(ms);
  return NULL;
  }
@@ -381,6 +395,8 @@ int media_session_end(struct media_session *ms, int leg, int nohold, int proxied
 
  MEDIA_SESSION_LOCK(ms);
  if (leg == MEDIA_LEG_BOTH) {
+ if (!ms->legs)
+ goto release;
  msl = ms->legs;
  nmsl = msl->next;
  if (nmsl) {