* Add a lock to be used in the update_call_counter function.
authorMark Michelson <mmichelson@digium.com>
Tue, 18 Nov 2008 20:23:58 +0000 (20:23 +0000)
committerMark Michelson <mmichelson@digium.com>
Tue, 18 Nov 2008 20:23:58 +0000 (20:23 +0000)
* Revert logic to mirror 1.4's in the sense that it will not allow
  the call counter to dip below 0.

These two measures prevent potential races that could cause a SIP peer
to appear to be busy forever.

(closes issue #13668)
Reported by: mjc
Patches:
      hintfix_trunk_rev152649.patch uploaded by wolfelectronic (license 586)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@157427 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

index f1601cd..9683330 100644 (file)
@@ -2118,6 +2118,9 @@ enum t38_action_flag {
        SDP_T38_ACCEPT,   /*!< Remote side accepted our T38 request */
 };
 
+/*! \brief Protect the callcounters inuse,inringing and the corresponding flags */
+AST_MUTEX_DEFINE_STATIC(callctrlock);
+
 /*---------------------------- Forward declarations of functions in chan_sip.c */
 /* Note: This is added to help splitting up chan_sip.c into several files
        in coming releases. */
@@ -5080,12 +5083,12 @@ static int update_call_counter(struct sip_pvt *fup, int event)
        ast_copy_string(name, fup->username, sizeof(name));
 
        /* Check the list of devices */
-       if ( (p = find_peer(ast_strlen_zero(fup->peername) ? name : fup->peername, NULL, TRUE, FINDALLDEVICES, FALSE) ) ) { /* Try to find peer */
+       if ((p = find_peer(ast_strlen_zero(fup->peername) ? name : fup->peername, NULL, TRUE, FINDALLDEVICES, FALSE))) { 
                inuse = &p->inUse;
                call_limit = &p->call_limit;
                inringing = &p->inRinging;
                ast_copy_string(name, fup->peername, sizeof(name));
-       } 
+       }
        if (!p) {
                ast_debug(2, "%s is not a local device, no call limit\n", name);
                return 0;
@@ -5095,20 +5098,37 @@ static int update_call_counter(struct sip_pvt *fup, int event)
        /* incoming and outgoing affects the inUse counter */
        case DEC_CALL_LIMIT:
                /* Decrement inuse count if applicable */
-               if (inuse && *inuse > 0 && ast_test_flag(&fup->flags[0], SIP_INC_COUNT)) {
-                       ast_atomic_fetchadd_int(inuse, -1);
-                       ast_clear_flag(&fup->flags[0], SIP_INC_COUNT);
-               } else
-                       *inuse = 0;
+               if (inuse) {
+                       ast_mutex_lock(&callctrlock);
+                       if ((*inuse > 0) && ast_test_flag(&fup->flags[0], SIP_INC_COUNT)) {
+                               (*inuse)--;
+                               ast_clear_flag(&fup->flags[0], SIP_INC_COUNT);
+                       } else {
+                               *inuse = 0;
+                       }
+                       ast_mutex_unlock(&callctrlock);
+               }
+
                /* Decrement ringing count if applicable */
-               if (inringing && *inringing > 0 && ast_test_flag(&fup->flags[0], SIP_INC_RINGING)) {
-                       ast_atomic_fetchadd_int(inringing, -1);
-                       ast_clear_flag(&fup->flags[0], SIP_INC_RINGING);
+               if (inringing) {
+                       ast_mutex_lock(&callctrlock);
+                       if ((*inringing > 0)&& ast_test_flag(&fup->flags[0], SIP_INC_RINGING)) {
+                               (*inringing)--;
+                               ast_clear_flag(&fup->flags[0], SIP_INC_RINGING);
+                       } else {
+                          *inringing = 0;
+                       }
+                       ast_mutex_unlock(&callctrlock);
                }
+
                /* Decrement onhold count if applicable */
+               ast_mutex_lock(&callctrlock);
                if (ast_test_flag(&fup->flags[1], SIP_PAGE2_CALL_ONHOLD) && global_notifyhold) {
                        ast_clear_flag(&fup->flags[1], SIP_PAGE2_CALL_ONHOLD);
+                       ast_mutex_unlock(&callctrlock);
                        sip_peer_hold(fup, FALSE);
+               } else {
+                       ast_mutex_unlock(&callctrlock);
                }
                if (sipdebug)
                        ast_debug(2, "Call %s %s '%s' removed from call limit %d\n", outgoing ? "to" : "from", "peer", name, *call_limit);
@@ -5125,29 +5145,41 @@ static int update_call_counter(struct sip_pvt *fup, int event)
                        }
                }
                if (inringing && (event == INC_CALL_RINGING)) {
+                       ast_mutex_lock(&callctrlock);
                        if (!ast_test_flag(&fup->flags[0], SIP_INC_RINGING)) {
-                               ast_atomic_fetchadd_int(inringing, +1);
+                               (*inringing)++;
                                ast_set_flag(&fup->flags[0], SIP_INC_RINGING);
                        }
+                       ast_mutex_unlock(&callctrlock);
+               }
+               if (inuse) {
+                       ast_mutex_lock(&callctrlock);
+                       if (!ast_test_flag(&fup->flags[0], SIP_INC_COUNT)) {
+                               (*inuse)++;
+                               ast_set_flag(&fup->flags[0], SIP_INC_COUNT);
+                       }
+                       ast_mutex_unlock(&callctrlock);
                }
-               /* Continue */
-               ast_atomic_fetchadd_int(inuse, +1);
-               ast_set_flag(&fup->flags[0], SIP_INC_COUNT);
                if (sipdebug) {
                        ast_debug(2, "Call %s %s '%s' is %d out of %d\n", outgoing ? "to" : "from", "peer", name, *inuse, *call_limit);
                }
                break;
 
        case DEC_CALL_RINGING:
-               if (inringing && *inringing > 0 && ast_test_flag(&fup->flags[0], SIP_INC_RINGING)) {
-                       ast_atomic_fetchadd_int(inringing, -1);
-                       ast_clear_flag(&fup->flags[0], SIP_INC_RINGING);
+               if (inringing) {
+                       ast_mutex_lock(&callctrlock);
+                       if (ast_test_flag(&fup->flags[0], SIP_INC_RINGING)) {
+                               (*inringing)--;
+                               ast_clear_flag(&fup->flags[0], SIP_INC_RINGING);
+                       }
+                       ast_mutex_unlock(&callctrlock);
                }
                break;
 
        default:
                ast_log(LOG_ERROR, "update_call_counter(%s, %d) called with no event!\n", name, event);
        }
+
        if (p) {
                ast_devstate_changed(AST_DEVICE_UNKNOWN, "SIP/%s", p->name);
                unref_peer(p, "update_call_counter: unref_peer from call counter");