]> git.ipfire.org Git - thirdparty/asterisk.git/commitdiff
app_sla: Migrate SLA applications out of app_meetme.
authorNaveen Albert <asterisk@phreaknet.org>
Tue, 2 May 2023 14:15:02 +0000 (14:15 +0000)
committerGeorge Joseph <gtjoseph@users.noreply.github.com>
Thu, 25 May 2023 16:34:35 +0000 (10:34 -0600)
This removes the dependency of the SLAStation and SLATrunk
applications on app_meetme, in anticipation of the imminent
removal of the deprecated app_meetme module.

The user interface for the SLA applications is exactly the
same, and in theory, users should not notice a difference.
However, the SLA applications now use ConfBridge under the
hood, rather than MeetMe, and they are now contained within
their own module.

Resolves: #50
ASTERISK-30309

UpgradeNote: The SLAStation and SLATrunk applications have been moved
from app_meetme to app_sla. If you are using these applications and have
autoload=no, you will need to explicitly load this module in modules.conf.

apps/app_meetme.c
apps/app_sla.c [new file with mode: 0644]

index 0d5bdc2570155bb9cbbb2e77ee721e21844747f3..9d130fb07fd3f98ae92a32100db5c114d8576919 100644 (file)
@@ -5,9 +5,6 @@
  *
  * Mark Spencer <markster@digium.com>
  *
- * SLA Implementation by:
- * Russell Bryant <russell@digium.com>
- *
  * See http://www.asterisk.org for more information about
  * the Asterisk project. Please do not directly contact
  * any of the maintainers of this project for assistance;
 
 /*! \file
  *
- * \brief Meet me conference bridge and Shared Line Appearances
+ * \brief Meet me conference bridge
  *
  * \author Mark Spencer <markster@digium.com>
- * \author (SLA) Russell Bryant <russell@digium.com>
  *
  * \ingroup applications
  */
                        <replaceable>channel</replaceable> in any conference.</para>
                </description>
        </application>
-       <application name="SLAStation" language="en_US">
-               <synopsis>
-                       Shared Line Appearance Station.
-               </synopsis>
-               <syntax>
-                       <parameter name="station" required="true">
-                               <para>Station name</para>
-                       </parameter>
-               </syntax>
-               <description>
-                       <para>This application should be executed by an SLA station. The argument depends
-                       on how the call was initiated. If the phone was just taken off hook, then the argument
-                       <replaceable>station</replaceable> should be just the station name. If the call was
-                       initiated by pressing a line key, then the station name should be preceded by an underscore
-                       and the trunk name associated with that line button.</para>
-                       <para>For example: <literal>station1_line1</literal></para>
-                       <para>On exit, this application will set the variable <variable>SLASTATION_STATUS</variable> to
-                       one of the following values:</para>
-                       <variablelist>
-                               <variable name="SLASTATION_STATUS">
-                                       <value name="FAILURE" />
-                                       <value name="CONGESTION" />
-                                       <value name="SUCCESS" />
-                               </variable>
-                       </variablelist>
-               </description>
-       </application>
-       <application name="SLATrunk" language="en_US">
-               <synopsis>
-                       Shared Line Appearance Trunk.
-               </synopsis>
-               <syntax>
-                       <parameter name="trunk" required="true">
-                               <para>Trunk name</para>
-                       </parameter>
-                       <parameter name="options">
-                               <optionlist>
-                                       <option name="M" hasparams="optional">
-                                               <para>Play back the specified MOH <replaceable>class</replaceable>
-                                               instead of ringing</para>
-                                               <argument name="class" required="true" />
-                                       </option>
-                               </optionlist>
-                       </parameter>
-               </syntax>
-               <description>
-                       <para>This application should be executed by an SLA trunk on an inbound call. The channel calling
-                       this application should correspond to the SLA trunk with the name <replaceable>trunk</replaceable>
-                       that is being passed as an argument.</para>
-                       <para>On exit, this application will set the variable <variable>SLATRUNK_STATUS</variable> to
-                       one of the following values:</para>
-                       <variablelist>
-                               <variable name="SLATRUNK_STATUS">
-                                       <value name="FAILURE" />
-                                       <value name="SUCCESS" />
-                                       <value name="UNANSWERED" />
-                                       <value name="RINGTIMEOUT" />
-                               </variable>
-                       </variablelist>
-               </description>
-       </application>
        <function name="MEETME_INFO" language="en_US">
                <synopsis>
                        Query a given conference of various properties.
  ***/
 
 #define CONFIG_FILE_NAME       "meetme.conf"
-#define SLA_CONFIG_FILE                "sla.conf"
 #define STR_CONCISE                    "concise"
 
 /*! each buffer is 20ms, so this is 640ms total */
@@ -811,12 +745,10 @@ enum {
        CONFFLAG_STARTMUTED = (1 << 24),
        /*! Pass DTMF through the conference */
        CONFFLAG_PASS_DTMF = (1 << 25),
-       CONFFLAG_SLA_STATION = (1 << 26),
-       CONFFLAG_SLA_TRUNK = (1 << 27),
        /*! If set, the user should continue in the dialplan if kicked out */
-       CONFFLAG_KICK_CONTINUE = (1 << 28),
-       CONFFLAG_DURATION_STOP = (1 << 29),
-       CONFFLAG_DURATION_LIMIT = (1 << 30),
+       CONFFLAG_KICK_CONTINUE = (1 << 26),
+       CONFFLAG_DURATION_STOP = (1 << 27),
+       CONFFLAG_DURATION_LIMIT = (1 << 28),
 };
 
 /* These flags are defined separately because we ran out of bits that an enum can be used to represent.
@@ -881,8 +813,6 @@ static const char * const app = "MeetMe";
 static const char * const app2 = "MeetMeCount";
 static const char * const app3 = "MeetMeAdmin";
 static const char * const app4 = "MeetMeChannelAdmin";
-static const char * const slastation_app = "SLAStation";
-static const char * const slatrunk_app = "SLATrunk";
 
 /* Lookup RealTime conferences based on confno and current time */
 static int rt_schedule;
@@ -993,192 +923,6 @@ struct ast_conf_user {
        AST_LIST_ENTRY(ast_conf_user) list;
 };
 
-enum sla_which_trunk_refs {
-       ALL_TRUNK_REFS,
-       INACTIVE_TRUNK_REFS,
-};
-
-enum sla_trunk_state {
-       SLA_TRUNK_STATE_IDLE,
-       SLA_TRUNK_STATE_RINGING,
-       SLA_TRUNK_STATE_UP,
-       SLA_TRUNK_STATE_ONHOLD,
-       SLA_TRUNK_STATE_ONHOLD_BYME,
-};
-
-enum sla_hold_access {
-       /*! This means that any station can put it on hold, and any station
-        * can retrieve the call from hold. */
-       SLA_HOLD_OPEN,
-       /*! This means that only the station that put the call on hold may
-        * retrieve it from hold. */
-       SLA_HOLD_PRIVATE,
-};
-
-struct sla_trunk_ref;
-
-struct sla_station {
-       AST_RWLIST_ENTRY(sla_station) entry;
-       AST_DECLARE_STRING_FIELDS(
-               AST_STRING_FIELD(name);
-               AST_STRING_FIELD(device);
-               AST_STRING_FIELD(autocontext);
-       );
-       AST_LIST_HEAD_NOLOCK(, sla_trunk_ref) trunks;
-       struct ast_dial *dial;
-       /*! Ring timeout for this station, for any trunk.  If a ring timeout
-        *  is set for a specific trunk on this station, that will take
-        *  priority over this value. */
-       unsigned int ring_timeout;
-       /*! Ring delay for this station, for any trunk.  If a ring delay
-        *  is set for a specific trunk on this station, that will take
-        *  priority over this value. */
-       unsigned int ring_delay;
-       /*! This option uses the values in the sla_hold_access enum and sets the
-        * access control type for hold on this station. */
-       unsigned int hold_access:1;
-       /*! Mark used during reload processing */
-       unsigned int mark:1;
-};
-
-/*!
- * \brief A reference to a station
- *
- * This struct looks near useless at first glance.  However, its existence
- * in the list of stations in sla_trunk means that this station references
- * that trunk.  We use the mark to keep track of whether it needs to be
- * removed from the sla_trunk's list of stations during a reload.
- */
-struct sla_station_ref {
-       AST_LIST_ENTRY(sla_station_ref) entry;
-       struct sla_station *station;
-       /*! Mark used during reload processing */
-       unsigned int mark:1;
-};
-
-struct sla_trunk {
-       AST_DECLARE_STRING_FIELDS(
-               AST_STRING_FIELD(name);
-               AST_STRING_FIELD(device);
-               AST_STRING_FIELD(autocontext);
-       );
-       AST_LIST_HEAD_NOLOCK(, sla_station_ref) stations;
-       /*! Number of stations that use this trunk */
-       unsigned int num_stations;
-       /*! Number of stations currently on a call with this trunk */
-       unsigned int active_stations;
-       /*! Number of stations that have this trunk on hold. */
-       unsigned int hold_stations;
-       struct ast_channel *chan;
-       unsigned int ring_timeout;
-       /*! If set to 1, no station will be able to join an active call with
-        *  this trunk. */
-       unsigned int barge_disabled:1;
-       /*! This option uses the values in the sla_hold_access enum and sets the
-        * access control type for hold on this trunk. */
-       unsigned int hold_access:1;
-       /*! Whether this trunk is currently on hold, meaning that once a station
-        *  connects to it, the trunk channel needs to have UNHOLD indicated to it. */
-       unsigned int on_hold:1;
-       /*! Mark used during reload processing */
-       unsigned int mark:1;
-};
-
-/*!
- * \brief A station's reference to a trunk
- *
- * An sla_station keeps a list of trunk_refs.  This holds metadata about the
- * stations usage of the trunk.
- */
-struct sla_trunk_ref {
-       AST_LIST_ENTRY(sla_trunk_ref) entry;
-       struct sla_trunk *trunk;
-       enum sla_trunk_state state;
-       struct ast_channel *chan;
-       /*! Ring timeout to use when this trunk is ringing on this specific
-        *  station.  This takes higher priority than a ring timeout set at
-        *  the station level. */
-       unsigned int ring_timeout;
-       /*! Ring delay to use when this trunk is ringing on this specific
-        *  station.  This takes higher priority than a ring delay set at
-        *  the station level. */
-       unsigned int ring_delay;
-       /*! Mark used during reload processing */
-       unsigned int mark:1;
-};
-
-static struct ao2_container *sla_stations;
-static struct ao2_container *sla_trunks;
-
-static const char sla_registrar[] = "SLA";
-
-/*! \brief Event types that can be queued up for the SLA thread */
-enum sla_event_type {
-       /*! A station has put the call on hold */
-       SLA_EVENT_HOLD,
-       /*! The state of a dial has changed */
-       SLA_EVENT_DIAL_STATE,
-       /*! The state of a ringing trunk has changed */
-       SLA_EVENT_RINGING_TRUNK,
-};
-
-struct sla_event {
-       enum sla_event_type type;
-       struct sla_station *station;
-       struct sla_trunk_ref *trunk_ref;
-       AST_LIST_ENTRY(sla_event) entry;
-};
-
-/*! \brief A station that failed to be dialed
- * \note Only used by the SLA thread. */
-struct sla_failed_station {
-       struct sla_station *station;
-       struct timeval last_try;
-       AST_LIST_ENTRY(sla_failed_station) entry;
-};
-
-/*! \brief A trunk that is ringing */
-struct sla_ringing_trunk {
-       struct sla_trunk *trunk;
-       /*! The time that this trunk started ringing */
-       struct timeval ring_begin;
-       AST_LIST_HEAD_NOLOCK(, sla_station_ref) timed_out_stations;
-       AST_LIST_ENTRY(sla_ringing_trunk) entry;
-};
-
-enum sla_station_hangup {
-       SLA_STATION_HANGUP_NORMAL,
-       SLA_STATION_HANGUP_TIMEOUT,
-};
-
-/*! \brief A station that is ringing */
-struct sla_ringing_station {
-       struct sla_station *station;
-       /*! The time that this station started ringing */
-       struct timeval ring_begin;
-       AST_LIST_ENTRY(sla_ringing_station) entry;
-};
-
-/*!
- * \brief A structure for data used by the sla thread
- */
-static struct {
-       /*! The SLA thread ID */
-       pthread_t thread;
-       ast_cond_t cond;
-       ast_mutex_t lock;
-       AST_LIST_HEAD_NOLOCK(, sla_ringing_trunk) ringing_trunks;
-       AST_LIST_HEAD_NOLOCK(, sla_ringing_station) ringing_stations;
-       AST_LIST_HEAD_NOLOCK(, sla_failed_station) failed_stations;
-       AST_LIST_HEAD_NOLOCK(, sla_event) event_q;
-       unsigned int stop:1;
-       /*! Attempt to handle CallerID, even though it is known not to work
-        *  properly in some situations. */
-       unsigned int attempt_callerid:1;
-} sla = {
-       .thread = AST_PTHREADT_NULL,
-};
-
 /*! \brief The number of audio buffers to be allocated on pseudo channels
  *  when in a conference */
 static int audio_buffers;
@@ -2070,7 +1814,6 @@ static char *meetme_show_cmd(struct ast_cli_entry *e, int cmd, struct ast_cli_ar
        return CLI_SHOWUSAGE;
 }
 
-
 static char *meetme_cmd_helper(struct ast_cli_args *a)
 {
        /* Process the command */
@@ -2191,187 +1934,11 @@ static char *meetme_mute_cmd(struct ast_cli_entry *e, int cmd, struct ast_cli_ar
        return meetme_cmd_helper(a);
 }
 
-static const char *sla_hold_str(unsigned int hold_access)
-{
-       const char *hold = "Unknown";
-
-       switch (hold_access) {
-       case SLA_HOLD_OPEN:
-               hold = "Open";
-               break;
-       case SLA_HOLD_PRIVATE:
-               hold = "Private";
-       default:
-               break;
-       }
-
-       return hold;
-}
-
-static char *sla_show_trunks(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
-{
-       struct ao2_iterator i;
-       struct sla_trunk *trunk;
-
-       switch (cmd) {
-       case CLI_INIT:
-               e->command = "sla show trunks";
-               e->usage =
-                       "Usage: sla show trunks\n"
-                       "       This will list all trunks defined in sla.conf\n";
-               return NULL;
-       case CLI_GENERATE:
-               return NULL;
-       }
-
-       ast_cli(a->fd, "\n"
-                   "=============================================================\n"
-                   "=== Configured SLA Trunks ===================================\n"
-                   "=============================================================\n"
-                   "===\n");
-       i = ao2_iterator_init(sla_trunks, 0);
-       for (; (trunk = ao2_iterator_next(&i)); ao2_ref(trunk, -1)) {
-               struct sla_station_ref *station_ref;
-               char ring_timeout[16] = "(none)";
-
-               ao2_lock(trunk);
-
-               if (trunk->ring_timeout) {
-                       snprintf(ring_timeout, sizeof(ring_timeout), "%u Seconds", trunk->ring_timeout);
-               }
-
-               ast_cli(a->fd, "=== ---------------------------------------------------------\n"
-                           "=== Trunk Name:       %s\n"
-                           "=== ==> Device:       %s\n"
-                           "=== ==> AutoContext:  %s\n"
-                           "=== ==> RingTimeout:  %s\n"
-                           "=== ==> BargeAllowed: %s\n"
-                           "=== ==> HoldAccess:   %s\n"
-                           "=== ==> Stations ...\n",
-                           trunk->name, trunk->device,
-                           S_OR(trunk->autocontext, "(none)"),
-                           ring_timeout,
-                           trunk->barge_disabled ? "No" : "Yes",
-                           sla_hold_str(trunk->hold_access));
-
-               AST_LIST_TRAVERSE(&trunk->stations, station_ref, entry) {
-                       ast_cli(a->fd, "===    ==> Station name: %s\n", station_ref->station->name);
-               }
-
-               ast_cli(a->fd, "=== ---------------------------------------------------------\n===\n");
-
-               ao2_unlock(trunk);
-       }
-       ao2_iterator_destroy(&i);
-       ast_cli(a->fd, "=============================================================\n\n");
-
-       return CLI_SUCCESS;
-}
-
-static const char *trunkstate2str(enum sla_trunk_state state)
-{
-#define S(e) case e: return # e;
-       switch (state) {
-       S(SLA_TRUNK_STATE_IDLE)
-       S(SLA_TRUNK_STATE_RINGING)
-       S(SLA_TRUNK_STATE_UP)
-       S(SLA_TRUNK_STATE_ONHOLD)
-       S(SLA_TRUNK_STATE_ONHOLD_BYME)
-       }
-       return "Uknown State";
-#undef S
-}
-
-static char *sla_show_stations(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
-{
-       struct ao2_iterator i;
-       struct sla_station *station;
-
-       switch (cmd) {
-       case CLI_INIT:
-               e->command = "sla show stations";
-               e->usage =
-                       "Usage: sla show stations\n"
-                       "       This will list all stations defined in sla.conf\n";
-               return NULL;
-       case CLI_GENERATE:
-               return NULL;
-       }
-
-       ast_cli(a->fd, "\n"
-                   "=============================================================\n"
-                   "=== Configured SLA Stations =================================\n"
-                   "=============================================================\n"
-                   "===\n");
-       i = ao2_iterator_init(sla_stations, 0);
-       for (; (station = ao2_iterator_next(&i)); ao2_ref(station, -1)) {
-               struct sla_trunk_ref *trunk_ref;
-               char ring_timeout[16] = "(none)";
-               char ring_delay[16] = "(none)";
-
-               ao2_lock(station);
-
-               if (station->ring_timeout) {
-                       snprintf(ring_timeout, sizeof(ring_timeout),
-                               "%u", station->ring_timeout);
-               }
-               if (station->ring_delay) {
-                       snprintf(ring_delay, sizeof(ring_delay),
-                               "%u", station->ring_delay);
-               }
-               ast_cli(a->fd, "=== ---------------------------------------------------------\n"
-                           "=== Station Name:    %s\n"
-                           "=== ==> Device:      %s\n"
-                           "=== ==> AutoContext: %s\n"
-                           "=== ==> RingTimeout: %s\n"
-                           "=== ==> RingDelay:   %s\n"
-                           "=== ==> HoldAccess:  %s\n"
-                           "=== ==> Trunks ...\n",
-                           station->name, station->device,
-                           S_OR(station->autocontext, "(none)"),
-                           ring_timeout, ring_delay,
-                           sla_hold_str(station->hold_access));
-               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-                       if (trunk_ref->ring_timeout) {
-                               snprintf(ring_timeout, sizeof(ring_timeout),
-                                       "%u", trunk_ref->ring_timeout);
-                       } else {
-                               strcpy(ring_timeout, "(none)");
-                       }
-                       if (trunk_ref->ring_delay) {
-                               snprintf(ring_delay, sizeof(ring_delay),
-                                       "%u", trunk_ref->ring_delay);
-                       } else {
-                               strcpy(ring_delay, "(none)");
-                       }
-
-                       ast_cli(a->fd, "===    ==> Trunk Name: %s\n"
-                   "===       ==> State:       %s\n"
-                   "===       ==> RingTimeout: %s\n"
-                   "===       ==> RingDelay:   %s\n",
-                   trunk_ref->trunk->name,
-                   trunkstate2str(trunk_ref->state),
-                   ring_timeout, ring_delay);
-               }
-               ast_cli(a->fd, "=== ---------------------------------------------------------\n"
-                           "===\n");
-
-               ao2_unlock(station);
-       }
-       ao2_iterator_destroy(&i);
-       ast_cli(a->fd, "============================================================\n"
-                   "\n");
-
-       return CLI_SUCCESS;
-}
-
 static struct ast_cli_entry cli_meetme[] = {
        AST_CLI_DEFINE(meetme_kick_cmd, "Kick a conference or a user in a conference."),
        AST_CLI_DEFINE(meetme_show_cmd, "List all conferences or a specific conference."),
        AST_CLI_DEFINE(meetme_lock_cmd, "Lock or unlock a conference to new users."),
        AST_CLI_DEFINE(meetme_mute_cmd, "Mute or unmute a conference or a user in a conference."),
-       AST_CLI_DEFINE(sla_show_trunks, "Show SLA Trunks"),
-       AST_CLI_DEFINE(sla_show_stations, "Show SLA Stations"),
 };
 
 static void conf_flush(int fd, struct ast_channel *chan)
@@ -2494,90 +2061,6 @@ static void conf_queue_dtmf(const struct ast_conference *conf,
        ao2_iterator_destroy(&user_iter);
 }
 
-static void sla_queue_event_full(enum sla_event_type type,
-       struct sla_trunk_ref *trunk_ref, struct sla_station *station, int lock)
-{
-       struct sla_event *event;
-
-       if (sla.thread == AST_PTHREADT_NULL) {
-               ao2_ref(station, -1);
-               ao2_ref(trunk_ref, -1);
-               return;
-       }
-
-       if (!(event = ast_calloc(1, sizeof(*event)))) {
-               ao2_ref(station, -1);
-               ao2_ref(trunk_ref, -1);
-               return;
-       }
-
-       event->type = type;
-       event->trunk_ref = trunk_ref;
-       event->station = station;
-
-       if (!lock) {
-               AST_LIST_INSERT_TAIL(&sla.event_q, event, entry);
-               return;
-       }
-
-       ast_mutex_lock(&sla.lock);
-       AST_LIST_INSERT_TAIL(&sla.event_q, event, entry);
-       ast_cond_signal(&sla.cond);
-       ast_mutex_unlock(&sla.lock);
-}
-
-static void sla_queue_event_nolock(enum sla_event_type type)
-{
-       sla_queue_event_full(type, NULL, NULL, 0);
-}
-
-static void sla_queue_event(enum sla_event_type type)
-{
-       sla_queue_event_full(type, NULL, NULL, 1);
-}
-
-/*! \brief Queue a SLA event from the conference */
-static void sla_queue_event_conf(enum sla_event_type type, struct ast_channel *chan,
-       struct ast_conference *conf)
-{
-       struct sla_station *station;
-       struct sla_trunk_ref *trunk_ref = NULL;
-       char *trunk_name;
-       struct ao2_iterator i;
-
-       trunk_name = ast_strdupa(conf->confno);
-       strsep(&trunk_name, "_");
-       if (ast_strlen_zero(trunk_name)) {
-               ast_log(LOG_ERROR, "Invalid conference name for SLA - '%s'!\n", conf->confno);
-               return;
-       }
-
-       i = ao2_iterator_init(sla_stations, 0);
-       while ((station = ao2_iterator_next(&i))) {
-               ao2_lock(station);
-               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-                       if (trunk_ref->chan == chan && !strcmp(trunk_ref->trunk->name, trunk_name)) {
-                               ao2_ref(trunk_ref, 1);
-                               break;
-                       }
-               }
-               ao2_unlock(station);
-               if (trunk_ref) {
-                       /* station reference given to sla_queue_event_full() */
-                       break;
-               }
-               ao2_ref(station, -1);
-       }
-       ao2_iterator_destroy(&i);
-
-       if (!trunk_ref) {
-               ast_debug(1, "Trunk not found for event!\n");
-               return;
-       }
-
-       sla_queue_event_full(type, trunk_ref, station, 1);
-}
-
 /*! \brief Decrement reference counts, as incremented by find_conf() */
 static int dispose_conf(struct ast_conference *conf)
 {
@@ -4345,14 +3828,6 @@ static int conf_run(struct ast_channel *chan, struct ast_conference *conf, struc
                                } else if ((f->frametype == AST_FRAME_DTMF_BEGIN || f->frametype == AST_FRAME_DTMF_END)
                                        && ast_test_flag64(confflags, CONFFLAG_PASS_DTMF)) {
                                        conf_queue_dtmf(conf, user, f);
-                               } else if (ast_test_flag64(confflags, CONFFLAG_SLA_STATION) && f->frametype == AST_FRAME_CONTROL) {
-                                       switch (f->subclass.integer) {
-                                       case AST_CONTROL_HOLD:
-                                               sla_queue_event_conf(SLA_EVENT_HOLD, chan, conf);
-                                               break;
-                                       default:
-                                               break;
-                                       }
                                } else if (f->frametype == AST_FRAME_NULL) {
                                        /* Ignore NULL frames. It is perfectly normal to get these if the person is muted. */
                                } else if (f->frametype == AST_FRAME_CONTROL) {
@@ -4762,7 +4237,6 @@ static struct ast_conference *find_conf_realtime(struct ast_channel *chan, char
        return cnf;
 }
 
-
 static struct ast_conference *find_conf(struct ast_channel *chan, char *confno, int make, int dynamic,
                                        char *dynamic_pin, size_t pin_buf_len, int refcount, struct ast_flags64 *confflags)
 {
@@ -5937,2169 +5411,88 @@ static void load_config_meetme(int reload)
        ast_config_destroy(cfg);
 }
 
-/*!
- * \internal
- * \brief Find an SLA trunk by name
- */
-static struct sla_trunk *sla_find_trunk(const char *name)
-{
-       struct sla_trunk tmp_trunk = {
-               .name = name,
-       };
-
-       return ao2_find(sla_trunks, &tmp_trunk, OBJ_POINTER);
-}
-
-/*!
- * \internal
- * \brief Find an SLA station by name
- */
-static struct sla_station *sla_find_station(const char *name)
+static int acf_meetme_info_eval(const char *keyword, const struct ast_conference *conf)
 {
-       struct sla_station tmp_station = {
-               .name = name,
-       };
+       if (!strcasecmp("lock", keyword)) {
+               return conf->locked;
+       } else if (!strcasecmp("parties", keyword)) {
+               return conf->users;
+       } else if (!strcasecmp("activity", keyword)) {
+               time_t now;
+               now = time(NULL);
+               return (now - conf->start);
+       } else if (!strcasecmp("dynamic", keyword)) {
+               return conf->isdynamic;
+       } else {
+               return -1;
+       }
 
-       return ao2_find(sla_stations, &tmp_station, OBJ_POINTER);
 }
 
-static int sla_check_station_hold_access(const struct sla_trunk *trunk,
-       const struct sla_station *station)
+static int acf_meetme_info(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
 {
-       struct sla_station_ref *station_ref;
-       struct sla_trunk_ref *trunk_ref;
+       struct ast_conference *conf;
+       char *parse;
+       int result = -2; /* only non-negative numbers valid, -1 is used elsewhere */
+       AST_DECLARE_APP_ARGS(args,
+               AST_APP_ARG(keyword);
+               AST_APP_ARG(confno);
+       );
 
-       /* For each station that has this call on hold, check for private hold. */
-       AST_LIST_TRAVERSE(&trunk->stations, station_ref, entry) {
-               AST_LIST_TRAVERSE(&station_ref->station->trunks, trunk_ref, entry) {
-                       if (trunk_ref->trunk != trunk || station_ref->station == station)
-                               continue;
-                       if (trunk_ref->state == SLA_TRUNK_STATE_ONHOLD_BYME &&
-                               station_ref->station->hold_access == SLA_HOLD_PRIVATE)
-                               return 1;
-                       return 0;
-               }
+       if (ast_strlen_zero(data)) {
+               ast_log(LOG_ERROR, "Syntax: MEETME_INFO() requires two arguments\n");
+               return -1;
        }
 
-       return 0;
-}
+       parse = ast_strdupa(data);
+       AST_STANDARD_APP_ARGS(args, parse);
 
-/*!
- * \brief Find a trunk reference on a station by name
- * \param station the station
- * \param name the trunk's name
- * \pre sla_station is locked
- * \return a pointer to the station's trunk reference.  If the trunk
- *         is not found, it is not idle and barge is disabled, or if
- *         it is on hold and private hold is set, then NULL will be returned.
- */
-static struct sla_trunk_ref *sla_find_trunk_ref_byname(const struct sla_station *station,
-       const char *name)
-{
-       struct sla_trunk_ref *trunk_ref = NULL;
+       if (ast_strlen_zero(args.keyword)) {
+               ast_log(LOG_ERROR, "Syntax: MEETME_INFO() requires a keyword\n");
+               return -1;
+       }
 
-       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-               if (strcasecmp(trunk_ref->trunk->name, name))
-                       continue;
+       if (ast_strlen_zero(args.confno)) {
+               ast_log(LOG_ERROR, "Syntax: MEETME_INFO() requires a conference number\n");
+               return -1;
+       }
 
-               if ( (trunk_ref->trunk->barge_disabled
-                       && trunk_ref->state == SLA_TRUNK_STATE_UP) ||
-                       (trunk_ref->trunk->hold_stations
-                       && trunk_ref->trunk->hold_access == SLA_HOLD_PRIVATE
-                       && trunk_ref->state != SLA_TRUNK_STATE_ONHOLD_BYME) ||
-                       sla_check_station_hold_access(trunk_ref->trunk, station) )
-               {
-                       trunk_ref = NULL;
+       AST_LIST_LOCK(&confs);
+       AST_LIST_TRAVERSE(&confs, conf, list) {
+               if (!strcmp(args.confno, conf->confno)) {
+                       result = acf_meetme_info_eval(args.keyword, conf);
+                       break;
                }
-
-               break;
        }
+       AST_LIST_UNLOCK(&confs);
 
-       if (trunk_ref) {
-               ao2_ref(trunk_ref, 1);
+       if (result > -1) {
+               snprintf(buf, len, "%d", result);
+       } else if (result == -1) {
+               ast_log(LOG_NOTICE, "Error: invalid keyword: '%s'\n", args.keyword);
+               snprintf(buf, len, "0");
+       } else if (result == -2) {
+               ast_log(LOG_NOTICE, "Error: conference (%s) not found\n", args.confno);
+               snprintf(buf, len, "0");
        }
 
-       return trunk_ref;
+       return 0;
 }
 
-static void sla_station_ref_destructor(void *obj)
-{
-       struct sla_station_ref *station_ref = obj;
+static struct ast_custom_function meetme_info_acf = {
+       .name = "MEETME_INFO",
+       .read = acf_meetme_info,
+};
 
-       if (station_ref->station) {
-               ao2_ref(station_ref->station, -1);
-               station_ref->station = NULL;
-       }
+static int load_config(int reload)
+{
+       load_config_meetme(reload);
+       return 0;
 }
 
-static struct sla_station_ref *sla_create_station_ref(struct sla_station *station)
+static int unload_module(void)
 {
-       struct sla_station_ref *station_ref;
-
-       if (!(station_ref = ao2_alloc(sizeof(*station_ref), sla_station_ref_destructor))) {
-               return NULL;
-       }
-
-       ao2_ref(station, 1);
-       station_ref->station = station;
-
-       return station_ref;
-}
-
-static struct sla_ringing_station *sla_create_ringing_station(struct sla_station *station)
-{
-       struct sla_ringing_station *ringing_station;
-
-       if (!(ringing_station = ast_calloc(1, sizeof(*ringing_station))))
-               return NULL;
-
-       ao2_ref(station, 1);
-       ringing_station->station = station;
-       ringing_station->ring_begin = ast_tvnow();
-
-       return ringing_station;
-}
-
-static void sla_ringing_station_destroy(struct sla_ringing_station *ringing_station)
-{
-       if (ringing_station->station) {
-               ao2_ref(ringing_station->station, -1);
-               ringing_station->station = NULL;
-       }
-
-       ast_free(ringing_station);
-}
-
-static struct sla_failed_station *sla_create_failed_station(struct sla_station *station)
-{
-       struct sla_failed_station *failed_station;
-
-       if (!(failed_station = ast_calloc(1, sizeof(*failed_station)))) {
-               return NULL;
-       }
-
-       ao2_ref(station, 1);
-       failed_station->station = station;
-       failed_station->last_try = ast_tvnow();
-
-       return failed_station;
-}
-
-static void sla_failed_station_destroy(struct sla_failed_station *failed_station)
-{
-       if (failed_station->station) {
-               ao2_ref(failed_station->station, -1);
-               failed_station->station = NULL;
-       }
-
-       ast_free(failed_station);
-}
-
-static enum ast_device_state sla_state_to_devstate(enum sla_trunk_state state)
-{
-       switch (state) {
-       case SLA_TRUNK_STATE_IDLE:
-               return AST_DEVICE_NOT_INUSE;
-       case SLA_TRUNK_STATE_RINGING:
-               return AST_DEVICE_RINGING;
-       case SLA_TRUNK_STATE_UP:
-               return AST_DEVICE_INUSE;
-       case SLA_TRUNK_STATE_ONHOLD:
-       case SLA_TRUNK_STATE_ONHOLD_BYME:
-               return AST_DEVICE_ONHOLD;
-       }
-
-       return AST_DEVICE_UNKNOWN;
-}
-
-static void sla_change_trunk_state(const struct sla_trunk *trunk, enum sla_trunk_state state,
-       enum sla_which_trunk_refs inactive_only, const struct sla_trunk_ref *exclude)
-{
-       struct sla_station *station;
-       struct sla_trunk_ref *trunk_ref;
-       struct ao2_iterator i;
-
-       i = ao2_iterator_init(sla_stations, 0);
-       while ((station = ao2_iterator_next(&i))) {
-               ao2_lock(station);
-               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-                       if (trunk_ref->trunk != trunk || (inactive_only ? trunk_ref->chan : 0)
-                                       || trunk_ref == exclude) {
-                               continue;
-                       }
-                       trunk_ref->state = state;
-                       ast_devstate_changed(sla_state_to_devstate(state), AST_DEVSTATE_CACHABLE,
-                                            "SLA:%s_%s", station->name, trunk->name);
-                       break;
-               }
-               ao2_unlock(station);
-               ao2_ref(station, -1);
-       }
-       ao2_iterator_destroy(&i);
-}
-
-struct run_station_args {
-       struct sla_station *station;
-       struct sla_trunk_ref *trunk_ref;
-       ast_mutex_t *cond_lock;
-       ast_cond_t *cond;
-};
-
-static void answer_trunk_chan(struct ast_channel *chan)
-{
-       ast_raw_answer(chan);
-       ast_indicate(chan, -1);
-}
-
-static void *run_station(void *data)
-{
-       RAII_VAR(struct sla_station *, station, NULL, ao2_cleanup);
-       RAII_VAR(struct sla_trunk_ref *, trunk_ref, NULL, ao2_cleanup);
-       struct ast_str *conf_name = ast_str_create(16);
-       struct ast_flags64 conf_flags = { 0 };
-       struct ast_conference *conf;
-
-       {
-               struct run_station_args *args = data;
-               station = args->station;
-               trunk_ref = args->trunk_ref;
-               ast_mutex_lock(args->cond_lock);
-               ast_cond_signal(args->cond);
-               ast_mutex_unlock(args->cond_lock);
-               /* args is no longer valid here. */
-       }
-
-       ast_atomic_fetchadd_int((int *) &trunk_ref->trunk->active_stations, 1);
-       ast_str_set(&conf_name, 0, "SLA_%s", trunk_ref->trunk->name);
-       ast_set_flag64(&conf_flags,
-               CONFFLAG_QUIET | CONFFLAG_MARKEDEXIT | CONFFLAG_PASS_DTMF | CONFFLAG_SLA_STATION);
-       answer_trunk_chan(trunk_ref->chan);
-       conf = build_conf(ast_str_buffer(conf_name), "", "", 0, 0, 1, trunk_ref->chan, NULL);
-       if (conf) {
-               conf_run(trunk_ref->chan, conf, &conf_flags, NULL);
-               dispose_conf(conf);
-               conf = NULL;
-       }
-       trunk_ref->chan = NULL;
-       if (ast_atomic_dec_and_test((int *) &trunk_ref->trunk->active_stations) &&
-               trunk_ref->state != SLA_TRUNK_STATE_ONHOLD_BYME) {
-               ast_str_append(&conf_name, 0, ",K");
-               admin_exec(NULL, ast_str_buffer(conf_name));
-               trunk_ref->trunk->hold_stations = 0;
-               sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
-       }
-
-       ast_dial_join(station->dial);
-       ast_dial_destroy(station->dial);
-       station->dial = NULL;
-       ast_free(conf_name);
-
-       return NULL;
-}
-
-static void sla_ringing_trunk_destroy(struct sla_ringing_trunk *ringing_trunk);
-
-static void sla_stop_ringing_trunk(struct sla_ringing_trunk *ringing_trunk)
-{
-       char buf[80];
-       struct sla_station_ref *station_ref;
-
-       snprintf(buf, sizeof(buf), "SLA_%s,K", ringing_trunk->trunk->name);
-       admin_exec(NULL, buf);
-       sla_change_trunk_state(ringing_trunk->trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
-
-       while ((station_ref = AST_LIST_REMOVE_HEAD(&ringing_trunk->timed_out_stations, entry))) {
-               ao2_ref(station_ref, -1);
-       }
-
-       sla_ringing_trunk_destroy(ringing_trunk);
-}
-
-static void sla_stop_ringing_station(struct sla_ringing_station *ringing_station,
-       enum sla_station_hangup hangup)
-{
-       struct sla_ringing_trunk *ringing_trunk;
-       struct sla_trunk_ref *trunk_ref;
-       struct sla_station_ref *station_ref;
-
-       ast_dial_join(ringing_station->station->dial);
-       ast_dial_destroy(ringing_station->station->dial);
-       ringing_station->station->dial = NULL;
-
-       if (hangup == SLA_STATION_HANGUP_NORMAL)
-               goto done;
-
-       /* If the station is being hung up because of a timeout, then add it to the
-        * list of timed out stations on each of the ringing trunks.  This is so
-        * that when doing further processing to figure out which stations should be
-        * ringing, which trunk to answer, determining timeouts, etc., we know which
-        * ringing trunks we should ignore. */
-       AST_LIST_TRAVERSE(&sla.ringing_trunks, ringing_trunk, entry) {
-               AST_LIST_TRAVERSE(&ringing_station->station->trunks, trunk_ref, entry) {
-                       if (ringing_trunk->trunk == trunk_ref->trunk)
-                               break;
-               }
-               if (!trunk_ref)
-                       continue;
-               if (!(station_ref = sla_create_station_ref(ringing_station->station)))
-                       continue;
-               AST_LIST_INSERT_TAIL(&ringing_trunk->timed_out_stations, station_ref, entry);
-       }
-
-done:
-       sla_ringing_station_destroy(ringing_station);
-}
-
-static void sla_dial_state_callback(struct ast_dial *dial)
-{
-       sla_queue_event(SLA_EVENT_DIAL_STATE);
-}
-
-/*! \brief Check to see if dialing this station already timed out for this ringing trunk
- * \note Assumes sla.lock is locked
- */
-static int sla_check_timed_out_station(const struct sla_ringing_trunk *ringing_trunk,
-       const struct sla_station *station)
-{
-       struct sla_station_ref *timed_out_station;
-
-       AST_LIST_TRAVERSE(&ringing_trunk->timed_out_stations, timed_out_station, entry) {
-               if (station == timed_out_station->station)
-                       return 1;
-       }
-
-       return 0;
-}
-
-/*! \brief Choose the highest priority ringing trunk for a station
- * \param station the station
- * \param rm remove the ringing trunk once selected
- * \param trunk_ref a place to store the pointer to this stations reference to
- *        the selected trunk
- * \return a pointer to the selected ringing trunk, or NULL if none found
- * \note Assumes that sla.lock is locked
- */
-static struct sla_ringing_trunk *sla_choose_ringing_trunk(struct sla_station *station,
-       struct sla_trunk_ref **trunk_ref, int rm)
-{
-       struct sla_trunk_ref *s_trunk_ref;
-       struct sla_ringing_trunk *ringing_trunk = NULL;
-
-       AST_LIST_TRAVERSE(&station->trunks, s_trunk_ref, entry) {
-               AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_trunks, ringing_trunk, entry) {
-                       /* Make sure this is the trunk we're looking for */
-                       if (s_trunk_ref->trunk != ringing_trunk->trunk)
-                               continue;
-
-                       /* This trunk on the station is ringing.  But, make sure this station
-                        * didn't already time out while this trunk was ringing. */
-                       if (sla_check_timed_out_station(ringing_trunk, station))
-                               continue;
-
-                       if (rm)
-                               AST_LIST_REMOVE_CURRENT(entry);
-
-                       if (trunk_ref) {
-                               ao2_ref(s_trunk_ref, 1);
-                               *trunk_ref = s_trunk_ref;
-                       }
-
-                       break;
-               }
-               AST_LIST_TRAVERSE_SAFE_END;
-
-               if (ringing_trunk)
-                       break;
-       }
-
-       return ringing_trunk;
-}
-
-static void sla_handle_dial_state_event(void)
-{
-       struct sla_ringing_station *ringing_station;
-
-       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_stations, ringing_station, entry) {
-               RAII_VAR(struct sla_trunk_ref *, s_trunk_ref, NULL, ao2_cleanup);
-               struct sla_ringing_trunk *ringing_trunk = NULL;
-               struct run_station_args args;
-               enum ast_dial_result dial_res;
-               pthread_t dont_care;
-               ast_mutex_t cond_lock;
-               ast_cond_t cond;
-
-               switch ((dial_res = ast_dial_state(ringing_station->station->dial))) {
-               case AST_DIAL_RESULT_HANGUP:
-               case AST_DIAL_RESULT_INVALID:
-               case AST_DIAL_RESULT_FAILED:
-               case AST_DIAL_RESULT_TIMEOUT:
-               case AST_DIAL_RESULT_UNANSWERED:
-                       AST_LIST_REMOVE_CURRENT(entry);
-                       sla_stop_ringing_station(ringing_station, SLA_STATION_HANGUP_NORMAL);
-                       break;
-               case AST_DIAL_RESULT_ANSWERED:
-                       AST_LIST_REMOVE_CURRENT(entry);
-                       /* Find the appropriate trunk to answer. */
-                       ast_mutex_lock(&sla.lock);
-                       ringing_trunk = sla_choose_ringing_trunk(ringing_station->station, &s_trunk_ref, 1);
-                       ast_mutex_unlock(&sla.lock);
-                       if (!ringing_trunk) {
-                               /* This case happens in a bit of a race condition.  If two stations answer
-                                * the outbound call at the same time, the first one will get connected to
-                                * the trunk.  When the second one gets here, it will not see any trunks
-                                * ringing so we have no idea what to conect it to.  So, we just hang up
-                                * on it. */
-                               ast_debug(1, "Found no ringing trunk for station '%s' to answer!\n", ringing_station->station->name);
-                               ast_dial_join(ringing_station->station->dial);
-                               ast_dial_destroy(ringing_station->station->dial);
-                               ringing_station->station->dial = NULL;
-                               sla_ringing_station_destroy(ringing_station);
-                               break;
-                       }
-                       /* Track the channel that answered this trunk */
-                       s_trunk_ref->chan = ast_dial_answered(ringing_station->station->dial);
-                       /* Actually answer the trunk */
-                       answer_trunk_chan(ringing_trunk->trunk->chan);
-                       sla_change_trunk_state(ringing_trunk->trunk, SLA_TRUNK_STATE_UP, ALL_TRUNK_REFS, NULL);
-                       /* Now, start a thread that will connect this station to the trunk.  The rest of
-                        * the code here sets up the thread and ensures that it is able to save the arguments
-                        * before they are no longer valid since they are allocated on the stack. */
-                       ao2_ref(s_trunk_ref, 1);
-                       args.trunk_ref = s_trunk_ref;
-                       ao2_ref(ringing_station->station, 1);
-                       args.station = ringing_station->station;
-                       args.cond = &cond;
-                       args.cond_lock = &cond_lock;
-                       sla_ringing_trunk_destroy(ringing_trunk);
-                       sla_ringing_station_destroy(ringing_station);
-                       ast_mutex_init(&cond_lock);
-                       ast_cond_init(&cond, NULL);
-                       ast_mutex_lock(&cond_lock);
-                       ast_pthread_create_detached_background(&dont_care, NULL, run_station, &args);
-                       ast_cond_wait(&cond, &cond_lock);
-                       ast_mutex_unlock(&cond_lock);
-                       ast_mutex_destroy(&cond_lock);
-                       ast_cond_destroy(&cond);
-                       break;
-               case AST_DIAL_RESULT_TRYING:
-               case AST_DIAL_RESULT_RINGING:
-               case AST_DIAL_RESULT_PROGRESS:
-               case AST_DIAL_RESULT_PROCEEDING:
-                       break;
-               }
-               if (dial_res == AST_DIAL_RESULT_ANSWERED) {
-                       /* Queue up reprocessing ringing trunks, and then ringing stations again */
-                       sla_queue_event(SLA_EVENT_RINGING_TRUNK);
-                       sla_queue_event(SLA_EVENT_DIAL_STATE);
-                       break;
-               }
-       }
-       AST_LIST_TRAVERSE_SAFE_END;
-}
-
-/*! \brief Check to see if this station is already ringing
- * \note Assumes sla.lock is locked
- */
-static int sla_check_ringing_station(const struct sla_station *station)
-{
-       struct sla_ringing_station *ringing_station;
-
-       AST_LIST_TRAVERSE(&sla.ringing_stations, ringing_station, entry) {
-               if (station == ringing_station->station)
-                       return 1;
-       }
-
-       return 0;
-}
-
-/*! \brief Check to see if this station has failed to be dialed in the past minute
- * \note assumes sla.lock is locked
- */
-static int sla_check_failed_station(const struct sla_station *station)
-{
-       struct sla_failed_station *failed_station;
-       int res = 0;
-
-       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.failed_stations, failed_station, entry) {
-               if (station != failed_station->station)
-                       continue;
-               if (ast_tvdiff_ms(ast_tvnow(), failed_station->last_try) > 1000) {
-                       AST_LIST_REMOVE_CURRENT(entry);
-                       sla_failed_station_destroy(failed_station);
-                       break;
-               }
-               res = 1;
-       }
-       AST_LIST_TRAVERSE_SAFE_END
-
-       return res;
-}
-
-/*! \brief Ring a station
- * \note Assumes sla.lock is locked
- */
-static int sla_ring_station(struct sla_ringing_trunk *ringing_trunk, struct sla_station *station)
-{
-       char *tech, *tech_data;
-       struct ast_dial *dial;
-       struct sla_ringing_station *ringing_station;
-       enum ast_dial_result res;
-       int caller_is_saved;
-       struct ast_party_caller caller;
-
-       if (!(dial = ast_dial_create()))
-               return -1;
-
-       ast_dial_set_state_callback(dial, sla_dial_state_callback);
-       tech_data = ast_strdupa(station->device);
-       tech = strsep(&tech_data, "/");
-
-       if (ast_dial_append(dial, tech, tech_data, NULL) == -1) {
-               ast_dial_destroy(dial);
-               return -1;
-       }
-
-       /* Do we need to save off the caller ID data? */
-       caller_is_saved = 0;
-       if (!sla.attempt_callerid) {
-               caller_is_saved = 1;
-               caller = *ast_channel_caller(ringing_trunk->trunk->chan);
-               ast_party_caller_init(ast_channel_caller(ringing_trunk->trunk->chan));
-       }
-
-       res = ast_dial_run(dial, ringing_trunk->trunk->chan, 1);
-
-       /* Restore saved caller ID */
-       if (caller_is_saved) {
-               ast_party_caller_free(ast_channel_caller(ringing_trunk->trunk->chan));
-               ast_channel_caller_set(ringing_trunk->trunk->chan, &caller);
-       }
-
-       if (res != AST_DIAL_RESULT_TRYING) {
-               struct sla_failed_station *failed_station;
-               ast_dial_destroy(dial);
-               if ((failed_station = sla_create_failed_station(station))) {
-                       AST_LIST_INSERT_HEAD(&sla.failed_stations, failed_station, entry);
-               }
-               return -1;
-       }
-       if (!(ringing_station = sla_create_ringing_station(station))) {
-               ast_dial_join(dial);
-               ast_dial_destroy(dial);
-               return -1;
-       }
-
-       station->dial = dial;
-
-       AST_LIST_INSERT_HEAD(&sla.ringing_stations, ringing_station, entry);
-
-       return 0;
-}
-
-/*! \brief Check to see if a station is in use
- */
-static int sla_check_inuse_station(const struct sla_station *station)
-{
-       struct sla_trunk_ref *trunk_ref;
-
-       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-               if (trunk_ref->chan)
-                       return 1;
-       }
-
-       return 0;
-}
-
-static struct sla_trunk_ref *sla_find_trunk_ref(const struct sla_station *station,
-       const struct sla_trunk *trunk)
-{
-       struct sla_trunk_ref *trunk_ref = NULL;
-
-       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-               if (trunk_ref->trunk == trunk)
-                       break;
-       }
-
-       ao2_ref(trunk_ref, 1);
-
-       return trunk_ref;
-}
-
-/*! \brief Calculate the ring delay for a given ringing trunk on a station
- * \param station the station
- * \param ringing_trunk the trunk.  If NULL, the highest priority ringing trunk will be used
- * \return the number of ms left before the delay is complete, or INT_MAX if there is no delay
- */
-static int sla_check_station_delay(struct sla_station *station,
-       struct sla_ringing_trunk *ringing_trunk)
-{
-       RAII_VAR(struct sla_trunk_ref *, trunk_ref, NULL, ao2_cleanup);
-       unsigned int delay = UINT_MAX;
-       int time_left, time_elapsed;
-
-       if (!ringing_trunk)
-               ringing_trunk = sla_choose_ringing_trunk(station, &trunk_ref, 0);
-       else
-               trunk_ref = sla_find_trunk_ref(station, ringing_trunk->trunk);
-
-       if (!ringing_trunk || !trunk_ref)
-               return delay;
-
-       /* If this station has a ring delay specific to the highest priority
-        * ringing trunk, use that.  Otherwise, use the ring delay specified
-        * globally for the station. */
-       delay = trunk_ref->ring_delay;
-       if (!delay)
-               delay = station->ring_delay;
-       if (!delay)
-               return INT_MAX;
-
-       time_elapsed = ast_tvdiff_ms(ast_tvnow(), ringing_trunk->ring_begin);
-       time_left = (delay * 1000) - time_elapsed;
-
-       return time_left;
-}
-
-/*! \brief Ring stations based on current set of ringing trunks
- * \note Assumes that sla.lock is locked
- */
-static void sla_ring_stations(void)
-{
-       struct sla_station_ref *station_ref;
-       struct sla_ringing_trunk *ringing_trunk;
-
-       /* Make sure that every station that uses at least one of the ringing
-        * trunks, is ringing. */
-       AST_LIST_TRAVERSE(&sla.ringing_trunks, ringing_trunk, entry) {
-               AST_LIST_TRAVERSE(&ringing_trunk->trunk->stations, station_ref, entry) {
-                       int time_left;
-
-                       /* Is this station already ringing? */
-                       if (sla_check_ringing_station(station_ref->station))
-                               continue;
-
-                       /* Is this station already in a call? */
-                       if (sla_check_inuse_station(station_ref->station))
-                               continue;
-
-                       /* Did we fail to dial this station earlier?  If so, has it been
-                        * a minute since we tried? */
-                       if (sla_check_failed_station(station_ref->station))
-                               continue;
-
-                       /* If this station already timed out while this trunk was ringing,
-                        * do not dial it again for this ringing trunk. */
-                       if (sla_check_timed_out_station(ringing_trunk, station_ref->station))
-                               continue;
-
-                       /* Check for a ring delay in progress */
-                       time_left = sla_check_station_delay(station_ref->station, ringing_trunk);
-                       if (time_left != INT_MAX && time_left > 0)
-                               continue;
-
-                       /* It is time to make this station begin to ring.  Do it! */
-                       sla_ring_station(ringing_trunk, station_ref->station);
-               }
-       }
-       /* Now, all of the stations that should be ringing, are ringing. */
-}
-
-static void sla_hangup_stations(void)
-{
-       struct sla_trunk_ref *trunk_ref;
-       struct sla_ringing_station *ringing_station;
-
-       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_stations, ringing_station, entry) {
-               AST_LIST_TRAVERSE(&ringing_station->station->trunks, trunk_ref, entry) {
-                       struct sla_ringing_trunk *ringing_trunk;
-                       ast_mutex_lock(&sla.lock);
-                       AST_LIST_TRAVERSE(&sla.ringing_trunks, ringing_trunk, entry) {
-                               if (trunk_ref->trunk == ringing_trunk->trunk)
-                                       break;
-                       }
-                       ast_mutex_unlock(&sla.lock);
-                       if (ringing_trunk)
-                               break;
-               }
-               if (!trunk_ref) {
-                       AST_LIST_REMOVE_CURRENT(entry);
-                       ast_dial_join(ringing_station->station->dial);
-                       ast_dial_destroy(ringing_station->station->dial);
-                       ringing_station->station->dial = NULL;
-                       sla_ringing_station_destroy(ringing_station);
-               }
-       }
-       AST_LIST_TRAVERSE_SAFE_END
-}
-
-static void sla_handle_ringing_trunk_event(void)
-{
-       ast_mutex_lock(&sla.lock);
-       sla_ring_stations();
-       ast_mutex_unlock(&sla.lock);
-
-       /* Find stations that shouldn't be ringing anymore. */
-       sla_hangup_stations();
-}
-
-static void sla_handle_hold_event(struct sla_event *event)
-{
-       ast_atomic_fetchadd_int((int *) &event->trunk_ref->trunk->hold_stations, 1);
-       event->trunk_ref->state = SLA_TRUNK_STATE_ONHOLD_BYME;
-       ast_devstate_changed(AST_DEVICE_ONHOLD, AST_DEVSTATE_CACHABLE, "SLA:%s_%s",
-                            event->station->name, event->trunk_ref->trunk->name);
-       sla_change_trunk_state(event->trunk_ref->trunk, SLA_TRUNK_STATE_ONHOLD,
-               INACTIVE_TRUNK_REFS, event->trunk_ref);
-
-       if (event->trunk_ref->trunk->active_stations == 1) {
-               /* The station putting it on hold is the only one on the call, so start
-                * Music on hold to the trunk. */
-               event->trunk_ref->trunk->on_hold = 1;
-               ast_indicate(event->trunk_ref->trunk->chan, AST_CONTROL_HOLD);
-       }
-
-       ast_softhangup(event->trunk_ref->chan, AST_SOFTHANGUP_DEV);
-       event->trunk_ref->chan = NULL;
-}
-
-/*! \brief Process trunk ring timeouts
- * \note Called with sla.lock locked
- * \return non-zero if a change to the ringing trunks was made
- */
-static int sla_calc_trunk_timeouts(unsigned int *timeout)
-{
-       struct sla_ringing_trunk *ringing_trunk;
-       int res = 0;
-
-       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_trunks, ringing_trunk, entry) {
-               int time_left, time_elapsed;
-               if (!ringing_trunk->trunk->ring_timeout)
-                       continue;
-               time_elapsed = ast_tvdiff_ms(ast_tvnow(), ringing_trunk->ring_begin);
-               time_left = (ringing_trunk->trunk->ring_timeout * 1000) - time_elapsed;
-               if (time_left <= 0) {
-                       pbx_builtin_setvar_helper(ringing_trunk->trunk->chan, "SLATRUNK_STATUS", "RINGTIMEOUT");
-                       AST_LIST_REMOVE_CURRENT(entry);
-                       sla_stop_ringing_trunk(ringing_trunk);
-                       res = 1;
-                       continue;
-               }
-               if (time_left < *timeout)
-                       *timeout = time_left;
-       }
-       AST_LIST_TRAVERSE_SAFE_END;
-
-       return res;
-}
-
-/*! \brief Process station ring timeouts
- * \note Called with sla.lock locked
- * \return non-zero if a change to the ringing stations was made
- */
-static int sla_calc_station_timeouts(unsigned int *timeout)
-{
-       struct sla_ringing_trunk *ringing_trunk;
-       struct sla_ringing_station *ringing_station;
-       int res = 0;
-
-       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_stations, ringing_station, entry) {
-               unsigned int ring_timeout = 0;
-               int time_elapsed, time_left = INT_MAX, final_trunk_time_left = INT_MIN;
-               struct sla_trunk_ref *trunk_ref;
-
-               /* If there are any ring timeouts specified for a specific trunk
-                * on the station, then use the highest per-trunk ring timeout.
-                * Otherwise, use the ring timeout set for the entire station. */
-               AST_LIST_TRAVERSE(&ringing_station->station->trunks, trunk_ref, entry) {
-                       struct sla_station_ref *station_ref;
-                       int trunk_time_elapsed, trunk_time_left;
-
-                       AST_LIST_TRAVERSE(&sla.ringing_trunks, ringing_trunk, entry) {
-                               if (ringing_trunk->trunk == trunk_ref->trunk)
-                                       break;
-                       }
-                       if (!ringing_trunk)
-                               continue;
-
-                       /* If there is a trunk that is ringing without a timeout, then the
-                        * only timeout that could matter is a global station ring timeout. */
-                       if (!trunk_ref->ring_timeout)
-                               break;
-
-                       /* This trunk on this station is ringing and has a timeout.
-                        * However, make sure this trunk isn't still ringing from a
-                        * previous timeout.  If so, don't consider it. */
-                       AST_LIST_TRAVERSE(&ringing_trunk->timed_out_stations, station_ref, entry) {
-                               if (station_ref->station == ringing_station->station)
-                                       break;
-                       }
-                       if (station_ref)
-                               continue;
-
-                       trunk_time_elapsed = ast_tvdiff_ms(ast_tvnow(), ringing_trunk->ring_begin);
-                       trunk_time_left = (trunk_ref->ring_timeout * 1000) - trunk_time_elapsed;
-                       if (trunk_time_left > final_trunk_time_left)
-                               final_trunk_time_left = trunk_time_left;
-               }
-
-               /* No timeout was found for ringing trunks, and no timeout for the entire station */
-               if (final_trunk_time_left == INT_MIN && !ringing_station->station->ring_timeout)
-                       continue;
-
-               /* Compute how much time is left for a global station timeout */
-               if (ringing_station->station->ring_timeout) {
-                       ring_timeout = ringing_station->station->ring_timeout;
-                       time_elapsed = ast_tvdiff_ms(ast_tvnow(), ringing_station->ring_begin);
-                       time_left = (ring_timeout * 1000) - time_elapsed;
-               }
-
-               /* If the time left based on the per-trunk timeouts is smaller than the
-                * global station ring timeout, use that. */
-               if (final_trunk_time_left > INT_MIN && final_trunk_time_left < time_left)
-                       time_left = final_trunk_time_left;
-
-               /* If there is no time left, the station needs to stop ringing */
-               if (time_left <= 0) {
-                       AST_LIST_REMOVE_CURRENT(entry);
-                       sla_stop_ringing_station(ringing_station, SLA_STATION_HANGUP_TIMEOUT);
-                       res = 1;
-                       continue;
-               }
-
-               /* There is still some time left for this station to ring, so save that
-                * timeout if it is the first event scheduled to occur */
-               if (time_left < *timeout)
-                       *timeout = time_left;
-       }
-       AST_LIST_TRAVERSE_SAFE_END;
-
-       return res;
-}
-
-/*! \brief Calculate the ring delay for a station
- * \note Assumes sla.lock is locked
- */
-static int sla_calc_station_delays(unsigned int *timeout)
-{
-       struct sla_station *station;
-       int res = 0;
-       struct ao2_iterator i;
-
-       i = ao2_iterator_init(sla_stations, 0);
-       for (; (station = ao2_iterator_next(&i)); ao2_ref(station, -1)) {
-               struct sla_ringing_trunk *ringing_trunk;
-               int time_left;
-
-               /* Ignore stations already ringing */
-               if (sla_check_ringing_station(station))
-                       continue;
-
-               /* Ignore stations already on a call */
-               if (sla_check_inuse_station(station))
-                       continue;
-
-               /* Ignore stations that don't have one of their trunks ringing */
-               if (!(ringing_trunk = sla_choose_ringing_trunk(station, NULL, 0)))
-                       continue;
-
-               if ((time_left = sla_check_station_delay(station, ringing_trunk)) == INT_MAX)
-                       continue;
-
-               /* If there is no time left, then the station needs to start ringing.
-                * Return non-zero so that an event will be queued up an event to
-                * make that happen. */
-               if (time_left <= 0) {
-                       res = 1;
-                       continue;
-               }
-
-               if (time_left < *timeout)
-                       *timeout = time_left;
-       }
-       ao2_iterator_destroy(&i);
-
-       return res;
-}
-
-/*! \brief Calculate the time until the next known event
- *  \note Called with sla.lock locked */
-static int sla_process_timers(struct timespec *ts)
-{
-       unsigned int timeout = UINT_MAX;
-       struct timeval wait;
-       unsigned int change_made = 0;
-
-       /* Check for ring timeouts on ringing trunks */
-       if (sla_calc_trunk_timeouts(&timeout))
-               change_made = 1;
-
-       /* Check for ring timeouts on ringing stations */
-       if (sla_calc_station_timeouts(&timeout))
-               change_made = 1;
-
-       /* Check for station ring delays */
-       if (sla_calc_station_delays(&timeout))
-               change_made = 1;
-
-       /* queue reprocessing of ringing trunks */
-       if (change_made)
-               sla_queue_event_nolock(SLA_EVENT_RINGING_TRUNK);
-
-       /* No timeout */
-       if (timeout == UINT_MAX)
-               return 0;
-
-       if (ts) {
-               wait = ast_tvadd(ast_tvnow(), ast_samp2tv(timeout, 1000));
-               ts->tv_sec = wait.tv_sec;
-               ts->tv_nsec = wait.tv_usec * 1000;
-       }
-
-       return 1;
-}
-
-static void sla_event_destroy(struct sla_event *event)
-{
-       if (event->trunk_ref) {
-               ao2_ref(event->trunk_ref, -1);
-               event->trunk_ref = NULL;
-       }
-
-       if (event->station) {
-               ao2_ref(event->station, -1);
-               event->station = NULL;
-       }
-
-       ast_free(event);
-}
-
-static void *sla_thread(void *data)
-{
-       struct sla_failed_station *failed_station;
-       struct sla_ringing_station *ringing_station;
-
-       ast_mutex_lock(&sla.lock);
-
-       while (!sla.stop) {
-               struct sla_event *event;
-               struct timespec ts = { 0, };
-               unsigned int have_timeout = 0;
-
-               if (AST_LIST_EMPTY(&sla.event_q)) {
-                       if ((have_timeout = sla_process_timers(&ts)))
-                               ast_cond_timedwait(&sla.cond, &sla.lock, &ts);
-                       else
-                               ast_cond_wait(&sla.cond, &sla.lock);
-                       if (sla.stop)
-                               break;
-               }
-
-               if (have_timeout)
-                       sla_process_timers(NULL);
-
-               while ((event = AST_LIST_REMOVE_HEAD(&sla.event_q, entry))) {
-                       ast_mutex_unlock(&sla.lock);
-                       switch (event->type) {
-                       case SLA_EVENT_HOLD:
-                               sla_handle_hold_event(event);
-                               break;
-                       case SLA_EVENT_DIAL_STATE:
-                               sla_handle_dial_state_event();
-                               break;
-                       case SLA_EVENT_RINGING_TRUNK:
-                               sla_handle_ringing_trunk_event();
-                               break;
-                       }
-                       sla_event_destroy(event);
-                       ast_mutex_lock(&sla.lock);
-               }
-       }
-
-       ast_mutex_unlock(&sla.lock);
-
-       while ((ringing_station = AST_LIST_REMOVE_HEAD(&sla.ringing_stations, entry))) {
-               sla_ringing_station_destroy(ringing_station);
-       }
-
-       while ((failed_station = AST_LIST_REMOVE_HEAD(&sla.failed_stations, entry))) {
-               sla_failed_station_destroy(failed_station);
-       }
-
-       return NULL;
-}
-
-struct dial_trunk_args {
-       struct sla_trunk_ref *trunk_ref;
-       struct sla_station *station;
-       ast_mutex_t *cond_lock;
-       ast_cond_t *cond;
-};
-
-static void *dial_trunk(void *data)
-{
-       struct dial_trunk_args *args = data;
-       struct ast_dial *dial;
-       char *tech, *tech_data;
-       enum ast_dial_result dial_res;
-       char conf_name[MAX_CONFNUM];
-       struct ast_conference *conf;
-       struct ast_flags64 conf_flags = { 0 };
-       RAII_VAR(struct sla_trunk_ref *, trunk_ref, args->trunk_ref, ao2_cleanup);
-       RAII_VAR(struct sla_station *, station, args->station, ao2_cleanup);
-       int caller_is_saved;
-       struct ast_party_caller caller;
-       int last_state = 0;
-       int current_state = 0;
-
-       if (!(dial = ast_dial_create())) {
-               ast_mutex_lock(args->cond_lock);
-               ast_cond_signal(args->cond);
-               ast_mutex_unlock(args->cond_lock);
-               return NULL;
-       }
-
-       tech_data = ast_strdupa(trunk_ref->trunk->device);
-       tech = strsep(&tech_data, "/");
-       if (ast_dial_append(dial, tech, tech_data, NULL) == -1) {
-               ast_mutex_lock(args->cond_lock);
-               ast_cond_signal(args->cond);
-               ast_mutex_unlock(args->cond_lock);
-               ast_dial_destroy(dial);
-               return NULL;
-       }
-
-       /* Do we need to save of the caller ID data? */
-       caller_is_saved = 0;
-       if (!sla.attempt_callerid) {
-               caller_is_saved = 1;
-               caller = *ast_channel_caller(trunk_ref->chan);
-               ast_party_caller_init(ast_channel_caller(trunk_ref->chan));
-       }
-
-       dial_res = ast_dial_run(dial, trunk_ref->chan, 1);
-
-       /* Restore saved caller ID */
-       if (caller_is_saved) {
-               ast_party_caller_free(ast_channel_caller(trunk_ref->chan));
-               ast_channel_caller_set(trunk_ref->chan, &caller);
-       }
-
-       if (dial_res != AST_DIAL_RESULT_TRYING) {
-               ast_mutex_lock(args->cond_lock);
-               ast_cond_signal(args->cond);
-               ast_mutex_unlock(args->cond_lock);
-               ast_dial_destroy(dial);
-               return NULL;
-       }
-
-       /* Wait for dial to end, while servicing the channel */
-       while (ast_waitfor(trunk_ref->chan, 100)) {
-               unsigned int done = 0;
-               struct ast_frame *fr = ast_read(trunk_ref->chan);
-
-               if (!fr) {
-                       ast_debug(1, "Channel %s did not return a frame, must have hung up\n", ast_channel_name(trunk_ref->chan));
-                       done = 1;
-                       break;
-               }
-               ast_frfree(fr); /* Ignore while dialing */
-
-               switch ((dial_res = ast_dial_state(dial))) {
-               case AST_DIAL_RESULT_ANSWERED:
-                       trunk_ref->trunk->chan = ast_dial_answered(dial);
-               case AST_DIAL_RESULT_HANGUP:
-               case AST_DIAL_RESULT_INVALID:
-               case AST_DIAL_RESULT_FAILED:
-               case AST_DIAL_RESULT_TIMEOUT:
-               case AST_DIAL_RESULT_UNANSWERED:
-                       done = 1;
-                       break;
-               case AST_DIAL_RESULT_TRYING:
-                       current_state = AST_CONTROL_PROGRESS;
-                       break;
-               case AST_DIAL_RESULT_RINGING:
-               case AST_DIAL_RESULT_PROGRESS:
-               case AST_DIAL_RESULT_PROCEEDING:
-                       current_state = AST_CONTROL_RINGING;
-                       break;
-               }
-               if (done)
-                       break;
-
-               /* check that SLA station that originated trunk call is still alive */
-               if (station && ast_device_state(station->device) == AST_DEVICE_NOT_INUSE) {
-                       ast_debug(3, "Originating station device %s no longer active\n", station->device);
-                       trunk_ref->trunk->chan = NULL;
-                       break;
-               }
-
-               /* If trunk line state changed, send indication back to originating SLA Station channel */
-               if (current_state != last_state) {
-                       ast_debug(3, "Indicating State Change %d to channel %s\n", current_state, ast_channel_name(trunk_ref->chan));
-                       ast_indicate(trunk_ref->chan, current_state);
-                       last_state = current_state;
-               }
-
-       }
-
-       if (!trunk_ref->trunk->chan) {
-               ast_mutex_lock(args->cond_lock);
-               ast_cond_signal(args->cond);
-               ast_mutex_unlock(args->cond_lock);
-               ast_dial_join(dial);
-               ast_dial_destroy(dial);
-               return NULL;
-       }
-
-       snprintf(conf_name, sizeof(conf_name), "SLA_%s", trunk_ref->trunk->name);
-       ast_set_flag64(&conf_flags,
-               CONFFLAG_QUIET | CONFFLAG_MARKEDEXIT | CONFFLAG_MARKEDUSER |
-               CONFFLAG_PASS_DTMF | CONFFLAG_SLA_TRUNK);
-       conf = build_conf(conf_name, "", "", 1, 1, 1, trunk_ref->trunk->chan, NULL);
-
-       ast_mutex_lock(args->cond_lock);
-       ast_cond_signal(args->cond);
-       ast_mutex_unlock(args->cond_lock);
-
-       if (conf) {
-               conf_run(trunk_ref->trunk->chan, conf, &conf_flags, NULL);
-               dispose_conf(conf);
-               conf = NULL;
-       }
-
-       /* If the trunk is going away, it is definitely now IDLE. */
-       sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
-
-       trunk_ref->trunk->chan = NULL;
-       trunk_ref->trunk->on_hold = 0;
-
-       ast_dial_join(dial);
-       ast_dial_destroy(dial);
-
-       return NULL;
-}
-
-/*!
- * \brief For a given station, choose the highest priority idle trunk
- * \pre sla_station is locked
- */
-static struct sla_trunk_ref *sla_choose_idle_trunk(const struct sla_station *station)
-{
-       struct sla_trunk_ref *trunk_ref = NULL;
-
-       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-               if (trunk_ref->state == SLA_TRUNK_STATE_IDLE) {
-                       ao2_ref(trunk_ref, 1);
-                       break;
-               }
-       }
-
-       return trunk_ref;
-}
-
-static int sla_station_exec(struct ast_channel *chan, const char *data)
-{
-       char *station_name, *trunk_name;
-       RAII_VAR(struct sla_station *, station, NULL, ao2_cleanup);
-       RAII_VAR(struct sla_trunk_ref *, trunk_ref, NULL, ao2_cleanup);
-       char conf_name[MAX_CONFNUM];
-       struct ast_flags64 conf_flags = { 0 };
-       struct ast_conference *conf;
-
-       if (ast_strlen_zero(data)) {
-               ast_log(LOG_WARNING, "Invalid Arguments to SLAStation!\n");
-               pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "FAILURE");
-               return 0;
-       }
-
-       trunk_name = ast_strdupa(data);
-       station_name = strsep(&trunk_name, "_");
-
-       if (ast_strlen_zero(station_name)) {
-               ast_log(LOG_WARNING, "Invalid Arguments to SLAStation!\n");
-               pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "FAILURE");
-               return 0;
-       }
-
-       station = sla_find_station(station_name);
-
-       if (!station) {
-               ast_log(LOG_WARNING, "Station '%s' not found!\n", station_name);
-               pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "FAILURE");
-               return 0;
-       }
-
-       ao2_lock(station);
-       if (!ast_strlen_zero(trunk_name)) {
-               trunk_ref = sla_find_trunk_ref_byname(station, trunk_name);
-       } else {
-               trunk_ref = sla_choose_idle_trunk(station);
-       }
-       ao2_unlock(station);
-
-       if (!trunk_ref) {
-               if (ast_strlen_zero(trunk_name))
-                       ast_log(LOG_NOTICE, "No trunks available for call.\n");
-               else {
-                       ast_log(LOG_NOTICE, "Can't join existing call on trunk "
-                               "'%s' due to access controls.\n", trunk_name);
-               }
-               pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "CONGESTION");
-               return 0;
-       }
-
-       if (trunk_ref->state == SLA_TRUNK_STATE_ONHOLD_BYME) {
-               if (ast_atomic_dec_and_test((int *) &trunk_ref->trunk->hold_stations) == 1)
-                       sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_UP, ALL_TRUNK_REFS, NULL);
-               else {
-                       trunk_ref->state = SLA_TRUNK_STATE_UP;
-                       ast_devstate_changed(AST_DEVICE_INUSE, AST_DEVSTATE_CACHABLE,
-                                            "SLA:%s_%s", station->name, trunk_ref->trunk->name);
-               }
-       } else if (trunk_ref->state == SLA_TRUNK_STATE_RINGING) {
-               struct sla_ringing_trunk *ringing_trunk;
-
-               ast_mutex_lock(&sla.lock);
-               AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_trunks, ringing_trunk, entry) {
-                       if (ringing_trunk->trunk == trunk_ref->trunk) {
-                               AST_LIST_REMOVE_CURRENT(entry);
-                               break;
-                       }
-               }
-               AST_LIST_TRAVERSE_SAFE_END
-               ast_mutex_unlock(&sla.lock);
-
-               if (ringing_trunk) {
-                       answer_trunk_chan(ringing_trunk->trunk->chan);
-                       sla_change_trunk_state(ringing_trunk->trunk, SLA_TRUNK_STATE_UP, ALL_TRUNK_REFS, NULL);
-
-                       sla_ringing_trunk_destroy(ringing_trunk);
-
-                       /* Queue up reprocessing ringing trunks, and then ringing stations again */
-                       sla_queue_event(SLA_EVENT_RINGING_TRUNK);
-                       sla_queue_event(SLA_EVENT_DIAL_STATE);
-               }
-       }
-
-       trunk_ref->chan = chan;
-
-       if (!trunk_ref->trunk->chan) {
-               ast_mutex_t cond_lock;
-               ast_cond_t cond;
-               pthread_t dont_care;
-               struct dial_trunk_args args = {
-                       .trunk_ref = trunk_ref,
-                       .station = station,
-                       .cond_lock = &cond_lock,
-                       .cond = &cond,
-               };
-               ao2_ref(trunk_ref, 1);
-               ao2_ref(station, 1);
-               sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_UP, ALL_TRUNK_REFS, NULL);
-               /* Create a thread to dial the trunk and dump it into the conference.
-                * However, we want to wait until the trunk has been dialed and the
-                * conference is created before continuing on here.
-                * Don't autoservice the channel or we'll have multiple threads
-                * handling it. dial_trunk services the channel.
-                */
-               ast_mutex_init(&cond_lock);
-               ast_cond_init(&cond, NULL);
-               ast_mutex_lock(&cond_lock);
-               ast_pthread_create_detached_background(&dont_care, NULL, dial_trunk, &args);
-               ast_cond_wait(&cond, &cond_lock);
-               ast_mutex_unlock(&cond_lock);
-               ast_mutex_destroy(&cond_lock);
-               ast_cond_destroy(&cond);
-
-               if (!trunk_ref->trunk->chan) {
-                       ast_debug(1, "Trunk didn't get created. chan: %lx\n", (unsigned long) trunk_ref->trunk->chan);
-                       pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "CONGESTION");
-                       sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
-                       trunk_ref->chan = NULL;
-                       return 0;
-               }
-       }
-
-       if (ast_atomic_fetchadd_int((int *) &trunk_ref->trunk->active_stations, 1) == 0 &&
-               trunk_ref->trunk->on_hold) {
-               trunk_ref->trunk->on_hold = 0;
-               ast_indicate(trunk_ref->trunk->chan, AST_CONTROL_UNHOLD);
-               sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_UP, ALL_TRUNK_REFS, NULL);
-       }
-
-       snprintf(conf_name, sizeof(conf_name), "SLA_%s", trunk_ref->trunk->name);
-       ast_set_flag64(&conf_flags,
-               CONFFLAG_QUIET | CONFFLAG_MARKEDEXIT | CONFFLAG_PASS_DTMF | CONFFLAG_SLA_STATION);
-       ast_answer(chan);
-       conf = build_conf(conf_name, "", "", 0, 0, 1, chan, NULL);
-       if (conf) {
-               conf_run(chan, conf, &conf_flags, NULL);
-               dispose_conf(conf);
-               conf = NULL;
-       }
-       trunk_ref->chan = NULL;
-       if (ast_atomic_dec_and_test((int *) &trunk_ref->trunk->active_stations) &&
-               trunk_ref->state != SLA_TRUNK_STATE_ONHOLD_BYME) {
-               strncat(conf_name, ",K", sizeof(conf_name) - strlen(conf_name) - 1);
-               admin_exec(NULL, conf_name);
-               trunk_ref->trunk->hold_stations = 0;
-               sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
-       }
-
-       pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "SUCCESS");
-
-       return 0;
-}
-
-static void sla_trunk_ref_destructor(void *obj)
-{
-       struct sla_trunk_ref *trunk_ref = obj;
-
-       if (trunk_ref->trunk) {
-               ao2_ref(trunk_ref->trunk, -1);
-               trunk_ref->trunk = NULL;
-       }
-}
-
-static struct sla_trunk_ref *create_trunk_ref(struct sla_trunk *trunk)
-{
-       struct sla_trunk_ref *trunk_ref;
-
-       if (!(trunk_ref = ao2_alloc(sizeof(*trunk_ref), sla_trunk_ref_destructor))) {
-               return NULL;
-       }
-
-       ao2_ref(trunk, 1);
-       trunk_ref->trunk = trunk;
-
-       return trunk_ref;
-}
-
-static struct sla_ringing_trunk *queue_ringing_trunk(struct sla_trunk *trunk)
-{
-       struct sla_ringing_trunk *ringing_trunk;
-
-       if (!(ringing_trunk = ast_calloc(1, sizeof(*ringing_trunk)))) {
-               return NULL;
-       }
-
-       ao2_ref(trunk, 1);
-       ringing_trunk->trunk = trunk;
-       ringing_trunk->ring_begin = ast_tvnow();
-
-       sla_change_trunk_state(trunk, SLA_TRUNK_STATE_RINGING, ALL_TRUNK_REFS, NULL);
-
-       ast_mutex_lock(&sla.lock);
-       AST_LIST_INSERT_HEAD(&sla.ringing_trunks, ringing_trunk, entry);
-       ast_mutex_unlock(&sla.lock);
-
-       sla_queue_event(SLA_EVENT_RINGING_TRUNK);
-
-       return ringing_trunk;
-}
-
-static void sla_ringing_trunk_destroy(struct sla_ringing_trunk *ringing_trunk)
-{
-       if (ringing_trunk->trunk) {
-               ao2_ref(ringing_trunk->trunk, -1);
-               ringing_trunk->trunk = NULL;
-       }
-
-       ast_free(ringing_trunk);
-}
-
-enum {
-       SLA_TRUNK_OPT_MOH = (1 << 0),
-};
-
-enum {
-       SLA_TRUNK_OPT_ARG_MOH_CLASS = 0,
-       SLA_TRUNK_OPT_ARG_ARRAY_SIZE = 1,
-};
-
-AST_APP_OPTIONS(sla_trunk_opts, BEGIN_OPTIONS
-       AST_APP_OPTION_ARG('M', SLA_TRUNK_OPT_MOH, SLA_TRUNK_OPT_ARG_MOH_CLASS),
-END_OPTIONS );
-
-static int sla_trunk_exec(struct ast_channel *chan, const char *data)
-{
-       char conf_name[MAX_CONFNUM];
-       struct ast_conference *conf;
-       struct ast_flags64 conf_flags = { 0 };
-       RAII_VAR(struct sla_trunk *, trunk, NULL, ao2_cleanup);
-       struct sla_ringing_trunk *ringing_trunk;
-       AST_DECLARE_APP_ARGS(args,
-               AST_APP_ARG(trunk_name);
-               AST_APP_ARG(options);
-       );
-       char *opts[SLA_TRUNK_OPT_ARG_ARRAY_SIZE] = { NULL, };
-       struct ast_flags opt_flags = { 0 };
-       char *parse;
-
-       if (ast_strlen_zero(data)) {
-               ast_log(LOG_ERROR, "The SLATrunk application requires an argument, the trunk name\n");
-               return -1;
-       }
-
-       parse = ast_strdupa(data);
-       AST_STANDARD_APP_ARGS(args, parse);
-       if (args.argc == 2) {
-               if (ast_app_parse_options(sla_trunk_opts, &opt_flags, opts, args.options)) {
-                       ast_log(LOG_ERROR, "Error parsing options for SLATrunk\n");
-                       return -1;
-               }
-       }
-
-       trunk = sla_find_trunk(args.trunk_name);
-
-       if (!trunk) {
-               ast_log(LOG_ERROR, "SLA Trunk '%s' not found!\n", args.trunk_name);
-               pbx_builtin_setvar_helper(chan, "SLATRUNK_STATUS", "FAILURE");
-               return 0;
-       }
-
-       if (trunk->chan) {
-               ast_log(LOG_ERROR, "Call came in on %s, but the trunk is already in use!\n",
-                       args.trunk_name);
-               pbx_builtin_setvar_helper(chan, "SLATRUNK_STATUS", "FAILURE");
-               return 0;
-       }
-
-       trunk->chan = chan;
-
-       if (!(ringing_trunk = queue_ringing_trunk(trunk))) {
-               pbx_builtin_setvar_helper(chan, "SLATRUNK_STATUS", "FAILURE");
-               return 0;
-       }
-
-       snprintf(conf_name, sizeof(conf_name), "SLA_%s", args.trunk_name);
-       conf = build_conf(conf_name, "", "", 1, 1, 1, chan, NULL);
-       if (!conf) {
-               pbx_builtin_setvar_helper(chan, "SLATRUNK_STATUS", "FAILURE");
-               return 0;
-       }
-       ast_set_flag64(&conf_flags,
-               CONFFLAG_QUIET | CONFFLAG_MARKEDEXIT | CONFFLAG_MARKEDUSER | CONFFLAG_PASS_DTMF | CONFFLAG_NO_AUDIO_UNTIL_UP);
-
-       if (ast_test_flag(&opt_flags, SLA_TRUNK_OPT_MOH)) {
-               ast_indicate(chan, -1);
-               ast_set_flag64(&conf_flags, CONFFLAG_MOH);
-       } else
-               ast_indicate(chan, AST_CONTROL_RINGING);
-
-       conf_run(chan, conf, &conf_flags, opts);
-       dispose_conf(conf);
-       conf = NULL;
-       trunk->chan = NULL;
-       trunk->on_hold = 0;
-
-       sla_change_trunk_state(trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
-
-       if (!pbx_builtin_getvar_helper(chan, "SLATRUNK_STATUS"))
-               pbx_builtin_setvar_helper(chan, "SLATRUNK_STATUS", "SUCCESS");
-
-       /* Remove the entry from the list of ringing trunks if it is still there. */
-       ast_mutex_lock(&sla.lock);
-       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_trunks, ringing_trunk, entry) {
-               if (ringing_trunk->trunk == trunk) {
-                       AST_LIST_REMOVE_CURRENT(entry);
-                       break;
-               }
-       }
-       AST_LIST_TRAVERSE_SAFE_END;
-       ast_mutex_unlock(&sla.lock);
-       if (ringing_trunk) {
-               sla_ringing_trunk_destroy(ringing_trunk);
-               pbx_builtin_setvar_helper(chan, "SLATRUNK_STATUS", "UNANSWERED");
-               /* Queue reprocessing of ringing trunks to make stations stop ringing
-                * that shouldn't be ringing after this trunk stopped. */
-               sla_queue_event(SLA_EVENT_RINGING_TRUNK);
-       }
-
-       return 0;
-}
-
-static enum ast_device_state sla_state(const char *data)
-{
-       char *buf, *station_name, *trunk_name;
-       RAII_VAR(struct sla_station *, station, NULL, ao2_cleanup);
-       struct sla_trunk_ref *trunk_ref;
-       enum ast_device_state res = AST_DEVICE_INVALID;
-
-       trunk_name = buf = ast_strdupa(data);
-       station_name = strsep(&trunk_name, "_");
-
-       station = sla_find_station(station_name);
-       if (station) {
-               ao2_lock(station);
-               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-                       if (!strcasecmp(trunk_name, trunk_ref->trunk->name)) {
-                               res = sla_state_to_devstate(trunk_ref->state);
-                               break;
-                       }
-               }
-               ao2_unlock(station);
-       }
-
-       if (res == AST_DEVICE_INVALID) {
-               ast_log(LOG_ERROR, "Could not determine state for trunk %s on station %s!\n",
-                       trunk_name, station_name);
-       }
-
-       return res;
-}
-
-static int sla_trunk_release_refs(void *obj, void *arg, int flags)
-{
-       struct sla_trunk *trunk = obj;
-       struct sla_station_ref *station_ref;
-
-       while ((station_ref = AST_LIST_REMOVE_HEAD(&trunk->stations, entry))) {
-               ao2_ref(station_ref, -1);
-       }
-
-       return 0;
-}
-
-static int sla_station_release_refs(void *obj, void *arg, int flags)
-{
-       struct sla_station *station = obj;
-       struct sla_trunk_ref *trunk_ref;
-
-       while ((trunk_ref = AST_LIST_REMOVE_HEAD(&station->trunks, entry))) {
-               ao2_ref(trunk_ref, -1);
-       }
-
-       return 0;
-}
-
-static void sla_station_destructor(void *obj)
-{
-       struct sla_station *station = obj;
-
-       ast_debug(1, "sla_station destructor for '%s'\n", station->name);
-
-       if (!ast_strlen_zero(station->autocontext)) {
-               struct sla_trunk_ref *trunk_ref;
-
-               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-                       char exten[AST_MAX_EXTENSION];
-                       char hint[AST_MAX_APP];
-                       snprintf(exten, sizeof(exten), "%s_%s", station->name, trunk_ref->trunk->name);
-                       snprintf(hint, sizeof(hint), "SLA:%s", exten);
-                       ast_context_remove_extension(station->autocontext, exten,
-                               1, sla_registrar);
-                       ast_context_remove_extension(station->autocontext, hint,
-                               PRIORITY_HINT, sla_registrar);
-               }
-       }
-
-       sla_station_release_refs(station, NULL, 0);
-
-       ast_string_field_free_memory(station);
-}
-
-static int sla_trunk_cmp(void *obj, void *arg, int flags)
-{
-       struct sla_trunk *trunk = obj, *trunk2 = arg;
-
-       return !strcasecmp(trunk->name, trunk2->name) ? CMP_MATCH | CMP_STOP : 0;
-}
-
-static int sla_station_cmp(void *obj, void *arg, int flags)
-{
-       struct sla_station *station = obj, *station2 = arg;
-
-       return !strcasecmp(station->name, station2->name) ? CMP_MATCH | CMP_STOP : 0;
-}
-
-static void sla_destroy(void)
-{
-       if (sla.thread != AST_PTHREADT_NULL) {
-               ast_mutex_lock(&sla.lock);
-               sla.stop = 1;
-               ast_cond_signal(&sla.cond);
-               ast_mutex_unlock(&sla.lock);
-               pthread_join(sla.thread, NULL);
-       }
-
-       /* Drop any created contexts from the dialplan */
-       ast_context_destroy(NULL, sla_registrar);
-
-       ast_mutex_destroy(&sla.lock);
-       ast_cond_destroy(&sla.cond);
-
-       ao2_callback(sla_trunks, 0, sla_trunk_release_refs, NULL);
-       ao2_callback(sla_stations, 0, sla_station_release_refs, NULL);
-
-       ao2_ref(sla_trunks, -1);
-       sla_trunks = NULL;
-
-       ao2_ref(sla_stations, -1);
-       sla_stations = NULL;
-}
-
-static int sla_check_device(const char *device)
-{
-       char *tech, *tech_data;
-
-       tech_data = ast_strdupa(device);
-       tech = strsep(&tech_data, "/");
-
-       if (ast_strlen_zero(tech) || ast_strlen_zero(tech_data))
-               return -1;
-
-       return 0;
-}
-
-static void sla_trunk_destructor(void *obj)
-{
-       struct sla_trunk *trunk = obj;
-
-       ast_debug(1, "sla_trunk destructor for '%s'\n", trunk->name);
-
-       if (!ast_strlen_zero(trunk->autocontext)) {
-               ast_context_remove_extension(trunk->autocontext, "s", 1, sla_registrar);
-       }
-
-       sla_trunk_release_refs(trunk, NULL, 0);
-
-       ast_string_field_free_memory(trunk);
-}
-
-static int sla_build_trunk(struct ast_config *cfg, const char *cat)
-{
-       RAII_VAR(struct sla_trunk *, trunk, NULL, ao2_cleanup);
-       struct ast_variable *var;
-       const char *dev;
-       int existing_trunk = 0;
-
-       if (!(dev = ast_variable_retrieve(cfg, cat, "device"))) {
-               ast_log(LOG_ERROR, "SLA Trunk '%s' defined with no device!\n", cat);
-               return -1;
-       }
-
-       if (sla_check_device(dev)) {
-               ast_log(LOG_ERROR, "SLA Trunk '%s' defined with invalid device '%s'!\n",
-                       cat, dev);
-               return -1;
-       }
-
-       if ((trunk = sla_find_trunk(cat))) {
-               trunk->mark = 0;
-               existing_trunk = 1;
-       } else if ((trunk = ao2_alloc(sizeof(*trunk), sla_trunk_destructor))) {
-               if (ast_string_field_init(trunk, 32)) {
-                       return -1;
-               }
-               ast_string_field_set(trunk, name, cat);
-       } else {
-               return -1;
-       }
-
-       ao2_lock(trunk);
-
-       ast_string_field_set(trunk, device, dev);
-
-       for (var = ast_variable_browse(cfg, cat); var; var = var->next) {
-               if (!strcasecmp(var->name, "autocontext"))
-                       ast_string_field_set(trunk, autocontext, var->value);
-               else if (!strcasecmp(var->name, "ringtimeout")) {
-                       if (sscanf(var->value, "%30u", &trunk->ring_timeout) != 1) {
-                               ast_log(LOG_WARNING, "Invalid ringtimeout '%s' specified for trunk '%s'\n",
-                                       var->value, trunk->name);
-                               trunk->ring_timeout = 0;
-                       }
-               } else if (!strcasecmp(var->name, "barge"))
-                       trunk->barge_disabled = ast_false(var->value);
-               else if (!strcasecmp(var->name, "hold")) {
-                       if (!strcasecmp(var->value, "private"))
-                               trunk->hold_access = SLA_HOLD_PRIVATE;
-                       else if (!strcasecmp(var->value, "open"))
-                               trunk->hold_access = SLA_HOLD_OPEN;
-                       else {
-                               ast_log(LOG_WARNING, "Invalid value '%s' for hold on trunk %s\n",
-                                       var->value, trunk->name);
-                       }
-               } else if (strcasecmp(var->name, "type") && strcasecmp(var->name, "device")) {
-                       ast_log(LOG_ERROR, "Invalid option '%s' specified at line %d of %s!\n",
-                               var->name, var->lineno, SLA_CONFIG_FILE);
-               }
-       }
-
-       ao2_unlock(trunk);
-
-       if (!ast_strlen_zero(trunk->autocontext)) {
-               if (!ast_context_find_or_create(NULL, NULL, trunk->autocontext, sla_registrar)) {
-                       ast_log(LOG_ERROR, "Failed to automatically find or create "
-                               "context '%s' for SLA!\n", trunk->autocontext);
-                       return -1;
-               }
-
-               if (ast_add_extension(trunk->autocontext, 0 /* don't replace */, "s", 1,
-                       NULL, NULL, slatrunk_app, ast_strdup(trunk->name), ast_free_ptr, sla_registrar)) {
-                       ast_log(LOG_ERROR, "Failed to automatically create extension "
-                               "for trunk '%s'!\n", trunk->name);
-                       return -1;
-               }
-       }
-
-       if (!existing_trunk) {
-               ao2_link(sla_trunks, trunk);
-       }
-
-       return 0;
-}
-
-/*!
- * \internal
- * \pre station is not locked
- */
-static void sla_add_trunk_to_station(struct sla_station *station, struct ast_variable *var)
-{
-       RAII_VAR(struct sla_trunk *, trunk, NULL, ao2_cleanup);
-       struct sla_trunk_ref *trunk_ref = NULL;
-       struct sla_station_ref *station_ref;
-       char *trunk_name, *options, *cur;
-       int existing_trunk_ref = 0;
-       int existing_station_ref = 0;
-
-       options = ast_strdupa(var->value);
-       trunk_name = strsep(&options, ",");
-
-       trunk = sla_find_trunk(trunk_name);
-       if (!trunk) {
-               ast_log(LOG_ERROR, "Trunk '%s' not found!\n", var->value);
-               return;
-       }
-
-       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-               if (trunk_ref->trunk == trunk) {
-                       trunk_ref->mark = 0;
-                       existing_trunk_ref = 1;
-                       break;
-               }
-       }
-
-       if (!trunk_ref && !(trunk_ref = create_trunk_ref(trunk))) {
-               return;
-       }
-
-       trunk_ref->state = SLA_TRUNK_STATE_IDLE;
-
-       while ((cur = strsep(&options, ","))) {
-               char *name, *value = cur;
-               name = strsep(&value, "=");
-               if (!strcasecmp(name, "ringtimeout")) {
-                       if (sscanf(value, "%30u", &trunk_ref->ring_timeout) != 1) {
-                               ast_log(LOG_WARNING, "Invalid ringtimeout value '%s' for "
-                                       "trunk '%s' on station '%s'\n", value, trunk->name, station->name);
-                               trunk_ref->ring_timeout = 0;
-                       }
-               } else if (!strcasecmp(name, "ringdelay")) {
-                       if (sscanf(value, "%30u", &trunk_ref->ring_delay) != 1) {
-                               ast_log(LOG_WARNING, "Invalid ringdelay value '%s' for "
-                                       "trunk '%s' on station '%s'\n", value, trunk->name, station->name);
-                               trunk_ref->ring_delay = 0;
-                       }
-               } else {
-                       ast_log(LOG_WARNING, "Invalid option '%s' for "
-                               "trunk '%s' on station '%s'\n", name, trunk->name, station->name);
-               }
-       }
-
-       AST_LIST_TRAVERSE(&trunk->stations, station_ref, entry) {
-               if (station_ref->station == station) {
-                       station_ref->mark = 0;
-                       existing_station_ref = 1;
-                       break;
-               }
-       }
-
-       if (!station_ref && !(station_ref = sla_create_station_ref(station))) {
-               if (!existing_trunk_ref) {
-                       ao2_ref(trunk_ref, -1);
-               } else {
-                       trunk_ref->mark = 1;
-               }
-               return;
-       }
-
-       if (!existing_station_ref) {
-               ao2_lock(trunk);
-               AST_LIST_INSERT_TAIL(&trunk->stations, station_ref, entry);
-               ast_atomic_fetchadd_int((int *) &trunk->num_stations, 1);
-               ao2_unlock(trunk);
-       }
-
-       if (!existing_trunk_ref) {
-               ao2_lock(station);
-               AST_LIST_INSERT_TAIL(&station->trunks, trunk_ref, entry);
-               ao2_unlock(station);
-       }
-}
-
-static int sla_build_station(struct ast_config *cfg, const char *cat)
-{
-       RAII_VAR(struct sla_station *, station, NULL, ao2_cleanup);
-       struct ast_variable *var;
-       const char *dev;
-       int existing_station = 0;
-
-       if (!(dev = ast_variable_retrieve(cfg, cat, "device"))) {
-               ast_log(LOG_ERROR, "SLA Station '%s' defined with no device!\n", cat);
-               return -1;
-       }
-
-       if ((station = sla_find_station(cat))) {
-               station->mark = 0;
-               existing_station = 1;
-       } else if ((station = ao2_alloc(sizeof(*station), sla_station_destructor))) {
-               if (ast_string_field_init(station, 32)) {
-                       return -1;
-               }
-               ast_string_field_set(station, name, cat);
-       } else {
-               return -1;
-       }
-
-       ao2_lock(station);
-
-       ast_string_field_set(station, device, dev);
-
-       for (var = ast_variable_browse(cfg, cat); var; var = var->next) {
-               if (!strcasecmp(var->name, "trunk")) {
-                       ao2_unlock(station);
-                       sla_add_trunk_to_station(station, var);
-                       ao2_lock(station);
-               } else if (!strcasecmp(var->name, "autocontext")) {
-                       ast_string_field_set(station, autocontext, var->value);
-               } else if (!strcasecmp(var->name, "ringtimeout")) {
-                       if (sscanf(var->value, "%30u", &station->ring_timeout) != 1) {
-                               ast_log(LOG_WARNING, "Invalid ringtimeout '%s' specified for station '%s'\n",
-                                       var->value, station->name);
-                               station->ring_timeout = 0;
-                       }
-               } else if (!strcasecmp(var->name, "ringdelay")) {
-                       if (sscanf(var->value, "%30u", &station->ring_delay) != 1) {
-                               ast_log(LOG_WARNING, "Invalid ringdelay '%s' specified for station '%s'\n",
-                                       var->value, station->name);
-                               station->ring_delay = 0;
-                       }
-               } else if (!strcasecmp(var->name, "hold")) {
-                       if (!strcasecmp(var->value, "private"))
-                               station->hold_access = SLA_HOLD_PRIVATE;
-                       else if (!strcasecmp(var->value, "open"))
-                               station->hold_access = SLA_HOLD_OPEN;
-                       else {
-                               ast_log(LOG_WARNING, "Invalid value '%s' for hold on station %s\n",
-                                       var->value, station->name);
-                       }
-
-               } else if (strcasecmp(var->name, "type") && strcasecmp(var->name, "device")) {
-                       ast_log(LOG_ERROR, "Invalid option '%s' specified at line %d of %s!\n",
-                               var->name, var->lineno, SLA_CONFIG_FILE);
-               }
-       }
-
-       ao2_unlock(station);
-
-       if (!ast_strlen_zero(station->autocontext)) {
-               struct sla_trunk_ref *trunk_ref;
-
-               if (!ast_context_find_or_create(NULL, NULL, station->autocontext, sla_registrar)) {
-                       ast_log(LOG_ERROR, "Failed to automatically find or create "
-                               "context '%s' for SLA!\n", station->autocontext);
-                       return -1;
-               }
-               /* The extension for when the handset goes off-hook.
-                * exten => station1,1,SLAStation(station1) */
-               if (ast_add_extension(station->autocontext, 0 /* don't replace */, station->name, 1,
-                       NULL, NULL, slastation_app, ast_strdup(station->name), ast_free_ptr, sla_registrar)) {
-                       ast_log(LOG_ERROR, "Failed to automatically create extension "
-                               "for trunk '%s'!\n", station->name);
-                       return -1;
-               }
-               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-                       char exten[AST_MAX_EXTENSION];
-                       char hint[AST_MAX_APP];
-                       snprintf(exten, sizeof(exten), "%s_%s", station->name, trunk_ref->trunk->name);
-                       snprintf(hint, sizeof(hint), "SLA:%s", exten);
-                       /* Extension for this line button
-                        * exten => station1_line1,1,SLAStation(station1_line1) */
-                       if (ast_add_extension(station->autocontext, 0 /* don't replace */, exten, 1,
-                               NULL, NULL, slastation_app, ast_strdup(exten), ast_free_ptr, sla_registrar)) {
-                               ast_log(LOG_ERROR, "Failed to automatically create extension "
-                                       "for trunk '%s'!\n", station->name);
-                               return -1;
-                       }
-                       /* Hint for this line button
-                        * exten => station1_line1,hint,SLA:station1_line1 */
-                       if (ast_add_extension(station->autocontext, 0 /* don't replace */, exten, PRIORITY_HINT,
-                               NULL, NULL, hint, NULL, NULL, sla_registrar)) {
-                               ast_log(LOG_ERROR, "Failed to automatically create hint "
-                                       "for trunk '%s'!\n", station->name);
-                               return -1;
-                       }
-               }
-       }
-
-       if (!existing_station) {
-               ao2_link(sla_stations, station);
-       }
-
-       return 0;
-}
-
-static int sla_trunk_mark(void *obj, void *arg, int flags)
-{
-       struct sla_trunk *trunk = obj;
-       struct sla_station_ref *station_ref;
-
-       ao2_lock(trunk);
-
-       trunk->mark = 1;
-
-       AST_LIST_TRAVERSE(&trunk->stations, station_ref, entry) {
-               station_ref->mark = 1;
-       }
-
-       ao2_unlock(trunk);
-
-       return 0;
-}
-
-static int sla_station_mark(void *obj, void *arg, int flags)
-{
-       struct sla_station *station = obj;
-       struct sla_trunk_ref *trunk_ref;
-
-       ao2_lock(station);
-
-       station->mark = 1;
-
-       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
-               trunk_ref->mark = 1;
-       }
-
-       ao2_unlock(station);
-
-       return 0;
-}
-
-static int sla_trunk_is_marked(void *obj, void *arg, int flags)
-{
-       struct sla_trunk *trunk = obj;
-
-       ao2_lock(trunk);
-
-       if (trunk->mark) {
-               /* Only remove all of the station references if the trunk itself is going away */
-               sla_trunk_release_refs(trunk, NULL, 0);
-       } else {
-               struct sla_station_ref *station_ref;
-
-               /* Otherwise only remove references to stations no longer in the config */
-               AST_LIST_TRAVERSE_SAFE_BEGIN(&trunk->stations, station_ref, entry) {
-                       if (!station_ref->mark) {
-                               continue;
-                       }
-                       AST_LIST_REMOVE_CURRENT(entry);
-                       ao2_ref(station_ref, -1);
-               }
-               AST_LIST_TRAVERSE_SAFE_END
-       }
-
-       ao2_unlock(trunk);
-
-       return trunk->mark ? CMP_MATCH : 0;
-}
-
-static int sla_station_is_marked(void *obj, void *arg, int flags)
-{
-       struct sla_station *station = obj;
-
-       ao2_lock(station);
-
-       if (station->mark) {
-               /* Only remove all of the trunk references if the station itself is going away */
-               sla_station_release_refs(station, NULL, 0);
-       } else {
-               struct sla_trunk_ref *trunk_ref;
-
-               /* Otherwise only remove references to trunks no longer in the config */
-               AST_LIST_TRAVERSE_SAFE_BEGIN(&station->trunks, trunk_ref, entry) {
-                       if (!trunk_ref->mark) {
-                               continue;
-                       }
-                       AST_LIST_REMOVE_CURRENT(entry);
-                       ao2_ref(trunk_ref, -1);
-               }
-               AST_LIST_TRAVERSE_SAFE_END
-       }
-
-       ao2_unlock(station);
-
-       return station->mark ? CMP_MATCH : 0;
-}
-
-static int sla_in_use(void)
-{
-       return ao2_container_count(sla_trunks) || ao2_container_count(sla_stations);
-}
-
-static int sla_load_config(int reload)
-{
-       struct ast_config *cfg;
-       struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
-       const char *cat = NULL;
-       int res = 0;
-       const char *val;
-
-       if (!reload) {
-               ast_mutex_init(&sla.lock);
-               ast_cond_init(&sla.cond, NULL);
-               sla_trunks = ao2_container_alloc_list(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
-                       NULL, sla_trunk_cmp);
-               sla_stations = ao2_container_alloc_list(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
-                       NULL, sla_station_cmp);
-       }
-
-       if (!(cfg = ast_config_load(SLA_CONFIG_FILE, config_flags))) {
-               return 0; /* Treat no config as normal */
-       } else if (cfg == CONFIG_STATUS_FILEUNCHANGED) {
-               return 0;
-       } else if (cfg == CONFIG_STATUS_FILEINVALID) {
-               ast_log(LOG_ERROR, "Config file " SLA_CONFIG_FILE " is in an invalid format.  Aborting.\n");
-               return 0;
-       }
-
-       if (reload) {
-               ao2_callback(sla_trunks, 0, sla_trunk_mark, NULL);
-               ao2_callback(sla_stations, 0, sla_station_mark, NULL);
-       }
-
-       if ((val = ast_variable_retrieve(cfg, "general", "attemptcallerid")))
-               sla.attempt_callerid = ast_true(val);
-
-       while ((cat = ast_category_browse(cfg, cat)) && !res) {
-               const char *type;
-               if (!strcasecmp(cat, "general"))
-                       continue;
-               if (!(type = ast_variable_retrieve(cfg, cat, "type"))) {
-                       ast_log(LOG_WARNING, "Invalid entry in %s defined with no type!\n",
-                               SLA_CONFIG_FILE);
-                       continue;
-               }
-               if (!strcasecmp(type, "trunk"))
-                       res = sla_build_trunk(cfg, cat);
-               else if (!strcasecmp(type, "station"))
-                       res = sla_build_station(cfg, cat);
-               else {
-                       ast_log(LOG_WARNING, "Entry in %s defined with invalid type '%s'!\n",
-                               SLA_CONFIG_FILE, type);
-               }
-       }
-
-       ast_config_destroy(cfg);
-
-       if (reload) {
-               ao2_callback(sla_trunks, OBJ_NODATA | OBJ_UNLINK | OBJ_MULTIPLE, sla_trunk_is_marked, NULL);
-               ao2_callback(sla_stations, OBJ_NODATA | OBJ_UNLINK | OBJ_MULTIPLE, sla_station_is_marked, NULL);
-       }
-
-       /* Start SLA event processing thread once SLA has been configured. */
-       if (sla.thread == AST_PTHREADT_NULL && sla_in_use()) {
-               ast_pthread_create(&sla.thread, NULL, sla_thread, NULL);
-       }
-
-       return res;
-}
-
-static int acf_meetme_info_eval(const char *keyword, const struct ast_conference *conf)
-{
-       if (!strcasecmp("lock", keyword)) {
-               return conf->locked;
-       } else if (!strcasecmp("parties", keyword)) {
-               return conf->users;
-       } else if (!strcasecmp("activity", keyword)) {
-               time_t now;
-               now = time(NULL);
-               return (now - conf->start);
-       } else if (!strcasecmp("dynamic", keyword)) {
-               return conf->isdynamic;
-       } else {
-               return -1;
-       }
-
-}
-
-static int acf_meetme_info(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
-{
-       struct ast_conference *conf;
-       char *parse;
-       int result = -2; /* only non-negative numbers valid, -1 is used elsewhere */
-       AST_DECLARE_APP_ARGS(args,
-               AST_APP_ARG(keyword);
-               AST_APP_ARG(confno);
-       );
-
-       if (ast_strlen_zero(data)) {
-               ast_log(LOG_ERROR, "Syntax: MEETME_INFO() requires two arguments\n");
-               return -1;
-       }
-
-       parse = ast_strdupa(data);
-       AST_STANDARD_APP_ARGS(args, parse);
-
-       if (ast_strlen_zero(args.keyword)) {
-               ast_log(LOG_ERROR, "Syntax: MEETME_INFO() requires a keyword\n");
-               return -1;
-       }
-
-       if (ast_strlen_zero(args.confno)) {
-               ast_log(LOG_ERROR, "Syntax: MEETME_INFO() requires a conference number\n");
-               return -1;
-       }
-
-       AST_LIST_LOCK(&confs);
-       AST_LIST_TRAVERSE(&confs, conf, list) {
-               if (!strcmp(args.confno, conf->confno)) {
-                       result = acf_meetme_info_eval(args.keyword, conf);
-                       break;
-               }
-       }
-       AST_LIST_UNLOCK(&confs);
-
-       if (result > -1) {
-               snprintf(buf, len, "%d", result);
-       } else if (result == -1) {
-               ast_log(LOG_NOTICE, "Error: invalid keyword: '%s'\n", args.keyword);
-               snprintf(buf, len, "0");
-       } else if (result == -2) {
-               ast_log(LOG_NOTICE, "Error: conference (%s) not found\n", args.confno);
-               snprintf(buf, len, "0");
-       }
-
-       return 0;
-}
-
-
-static struct ast_custom_function meetme_info_acf = {
-       .name = "MEETME_INFO",
-       .read = acf_meetme_info,
-};
-
-
-static int load_config(int reload)
-{
-       load_config_meetme(reload);
-       return sla_load_config(reload);
-}
-
-static int unload_module(void)
-{
-       int res = 0;
+       int res = 0;
 
        ast_cli_unregister_multiple(cli_meetme, ARRAY_LEN(cli_meetme));
        res = ast_manager_unregister("MeetmeMute");
@@ -8110,13 +5503,8 @@ static int unload_module(void)
        res |= ast_unregister_application(app3);
        res |= ast_unregister_application(app2);
        res |= ast_unregister_application(app);
-       res |= ast_unregister_application(slastation_app);
-       res |= ast_unregister_application(slatrunk_app);
 
        ast_devstate_prov_del("Meetme");
-       ast_devstate_prov_del("SLA");
-
-       sla_destroy();
 
        res |= ast_custom_function_unregister(&meetme_info_acf);
        ast_unload_realtime("meetme");
@@ -8153,11 +5541,8 @@ static int load_module(void)
        res |= ast_register_application_xml(app3, admin_exec);
        res |= ast_register_application_xml(app2, count_exec);
        res |= ast_register_application_xml(app, conf_exec);
-       res |= ast_register_application_xml(slastation_app, sla_station_exec);
-       res |= ast_register_application_xml(slatrunk_app, sla_trunk_exec);
 
        res |= ast_devstate_prov_add("Meetme", meetmestate);
-       res |= ast_devstate_prov_add("SLA", sla_state);
 
        res |= ast_custom_function_register(&meetme_info_acf);
        ast_realtime_require_field("meetme", "confno", RQ_UINTEGER2, 3, "members", RQ_UINTEGER1, 3, NULL);
diff --git a/apps/app_sla.c b/apps/app_sla.c
new file mode 100644 (file)
index 0000000..f1bd432
--- /dev/null
@@ -0,0 +1,2875 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2022, Naveen Albert
+ *
+ * Based on previous MeetMe-based SLA Implementation by:
+ * Russell Bryant <russell@digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*! \file
+ *
+ * \brief Shared Line Appearances
+ *
+ * \author Naveen Albert <asterisk@phreaknet.org>
+ *
+ * \ingroup applications
+ */
+
+/*! \li \ref app_sla.c uses configuration file \ref sla.conf
+ * \addtogroup configuration_file Configuration Files
+ */
+
+/*!
+ * \page sla.conf sla.conf
+ * \verbinclude sla.conf.sample
+ */
+
+/*** MODULEINFO
+       <depend>app_confbridge</depend>
+       <support_level>extended</support_level>
+ ***/
+
+#include "asterisk.h"
+
+#include "asterisk/lock.h"
+#include "asterisk/file.h"
+#include "asterisk/channel.h"
+#include "asterisk/pbx.h"
+#include "asterisk/module.h"
+#include "asterisk/config.h"
+#include "asterisk/app.h"
+#include "asterisk/cli.h"
+#include "asterisk/utils.h"
+#include "asterisk/astobj2.h"
+#include "asterisk/devicestate.h"
+#include "asterisk/dial.h"
+#include "asterisk/causes.h"
+#include "asterisk/format_compatibility.h"
+
+/*** DOCUMENTATION
+       <application name="SLAStation" language="en_US">
+               <synopsis>
+                       Shared Line Appearance Station.
+               </synopsis>
+               <syntax>
+                       <parameter name="station" required="true">
+                               <para>Station name</para>
+                       </parameter>
+               </syntax>
+               <description>
+                       <para>This application should be executed by an SLA station. The argument depends
+                       on how the call was initiated. If the phone was just taken off hook, then the argument
+                       <replaceable>station</replaceable> should be just the station name. If the call was
+                       initiated by pressing a line key, then the station name should be preceded by an underscore
+                       and the trunk name associated with that line button.</para>
+                       <para>For example: <literal>station1_line1</literal></para>
+                       <para>On exit, this application will set the variable <variable>SLASTATION_STATUS</variable> to
+                       one of the following values:</para>
+                       <variablelist>
+                               <variable name="SLASTATION_STATUS">
+                                       <value name="FAILURE" />
+                                       <value name="CONGESTION" />
+                                       <value name="SUCCESS" />
+                               </variable>
+                       </variablelist>
+               </description>
+       </application>
+       <application name="SLATrunk" language="en_US">
+               <synopsis>
+                       Shared Line Appearance Trunk.
+               </synopsis>
+               <syntax>
+                       <parameter name="trunk" required="true">
+                               <para>Trunk name</para>
+                       </parameter>
+                       <parameter name="options">
+                               <optionlist>
+                                       <option name="M" hasparams="optional">
+                                               <para>Play back the specified MOH <replaceable>class</replaceable>
+                                               instead of ringing</para>
+                                               <argument name="class" required="true" />
+                                       </option>
+                               </optionlist>
+                       </parameter>
+               </syntax>
+               <description>
+                       <para>This application should be executed by an SLA trunk on an inbound call. The channel calling
+                       this application should correspond to the SLA trunk with the name <replaceable>trunk</replaceable>
+                       that is being passed as an argument.</para>
+                       <para>On exit, this application will set the variable <variable>SLATRUNK_STATUS</variable> to
+                       one of the following values:</para>
+                       <variablelist>
+                               <variable name="SLATRUNK_STATUS">
+                                       <value name="FAILURE" />
+                                       <value name="SUCCESS" />
+                                       <value name="UNANSWERED" />
+                                       <value name="RINGTIMEOUT" />
+                               </variable>
+                       </variablelist>
+               </description>
+       </application>
+ ***/
+
+#define SLA_CONFIG_FILE                "sla.conf"
+#define MAX_CONFNUM 80
+
+static const char * const slastation_app = "SLAStation";
+static const char * const slatrunk_app = "SLATrunk";
+
+enum {
+       /*! If set there will be no enter or leave sounds */
+       CONFFLAG_QUIET = (1 << 0),
+       /*! Set to have music on hold when user is alone in conference */
+       CONFFLAG_MOH = (1 << 1),
+       /*! If set, the channel will leave the conference if all marked users leave */
+       CONFFLAG_MARKEDEXIT = (1 << 2),
+       /*! If set, the user will be marked */
+       CONFFLAG_MARKEDUSER = (1 << 3),
+       /*! Pass DTMF through the conference */
+       CONFFLAG_PASS_DTMF = (1 << 4),
+       CONFFLAG_SLA_STATION = (1 << 5),
+       CONFFLAG_SLA_TRUNK = (1 << 6),
+};
+
+enum {
+       SLA_TRUNK_OPT_MOH = (1 << 0),
+};
+
+enum {
+       SLA_TRUNK_OPT_ARG_MOH_CLASS = 0,
+       SLA_TRUNK_OPT_ARG_ARRAY_SIZE = 1,
+};
+
+AST_APP_OPTIONS(sla_trunk_opts, BEGIN_OPTIONS
+       AST_APP_OPTION_ARG('M', SLA_TRUNK_OPT_MOH, SLA_TRUNK_OPT_ARG_MOH_CLASS),
+END_OPTIONS );
+
+enum sla_which_trunk_refs {
+       ALL_TRUNK_REFS,
+       INACTIVE_TRUNK_REFS,
+};
+
+enum sla_trunk_state {
+       SLA_TRUNK_STATE_IDLE,
+       SLA_TRUNK_STATE_RINGING,
+       SLA_TRUNK_STATE_UP,
+       SLA_TRUNK_STATE_ONHOLD,
+       SLA_TRUNK_STATE_ONHOLD_BYME,
+};
+
+enum sla_hold_access {
+       /*! This means that any station can put it on hold, and any station
+        * can retrieve the call from hold. */
+       SLA_HOLD_OPEN,
+       /*! This means that only the station that put the call on hold may
+        * retrieve it from hold. */
+       SLA_HOLD_PRIVATE,
+};
+
+struct sla_trunk_ref;
+
+struct sla_station {
+       AST_RWLIST_ENTRY(sla_station) entry;
+       AST_DECLARE_STRING_FIELDS(
+               AST_STRING_FIELD(name);
+               AST_STRING_FIELD(device);
+               AST_STRING_FIELD(autocontext);
+       );
+       AST_LIST_HEAD_NOLOCK(, sla_trunk_ref) trunks;
+       struct ast_dial *dial;
+       /*! Ring timeout for this station, for any trunk.  If a ring timeout
+        *  is set for a specific trunk on this station, that will take
+        *  priority over this value. */
+       unsigned int ring_timeout;
+       /*! Ring delay for this station, for any trunk.  If a ring delay
+        *  is set for a specific trunk on this station, that will take
+        *  priority over this value. */
+       unsigned int ring_delay;
+       /*! This option uses the values in the sla_hold_access enum and sets the
+        * access control type for hold on this station. */
+       unsigned int hold_access:1;
+       /*! Mark used during reload processing */
+       unsigned int mark:1;
+};
+
+/*!
+ * \brief A reference to a station
+ *
+ * This struct looks near useless at first glance.  However, its existence
+ * in the list of stations in sla_trunk means that this station references
+ * that trunk.  We use the mark to keep track of whether it needs to be
+ * removed from the sla_trunk's list of stations during a reload.
+ */
+struct sla_station_ref {
+       AST_LIST_ENTRY(sla_station_ref) entry;
+       struct sla_station *station;
+       /*! Mark used during reload processing */
+       unsigned int mark:1;
+};
+
+struct sla_trunk {
+       AST_DECLARE_STRING_FIELDS(
+               AST_STRING_FIELD(name);
+               AST_STRING_FIELD(device);
+               AST_STRING_FIELD(autocontext);
+       );
+       AST_LIST_HEAD_NOLOCK(, sla_station_ref) stations;
+       /*! Number of stations that use this trunk */
+       unsigned int num_stations;
+       /*! Number of stations currently on a call with this trunk */
+       unsigned int active_stations;
+       /*! Number of stations that have this trunk on hold. */
+       unsigned int hold_stations;
+       struct ast_channel *chan;
+       unsigned int ring_timeout;
+       /*! If set to 1, no station will be able to join an active call with
+        *  this trunk. */
+       unsigned int barge_disabled:1;
+       /*! This option uses the values in the sla_hold_access enum and sets the
+        * access control type for hold on this trunk. */
+       unsigned int hold_access:1;
+       /*! Whether this trunk is currently on hold, meaning that once a station
+        *  connects to it, the trunk channel needs to have UNHOLD indicated to it. */
+       unsigned int on_hold:1;
+       /*! Mark used during reload processing */
+       unsigned int mark:1;
+};
+
+/*!
+ * \brief A station's reference to a trunk
+ *
+ * An sla_station keeps a list of trunk_refs.  This holds metadata about the
+ * stations usage of the trunk.
+ */
+struct sla_trunk_ref {
+       AST_LIST_ENTRY(sla_trunk_ref) entry;
+       struct sla_trunk *trunk;
+       enum sla_trunk_state state;
+       struct ast_channel *chan;
+       /*! Ring timeout to use when this trunk is ringing on this specific
+        *  station.  This takes higher priority than a ring timeout set at
+        *  the station level. */
+       unsigned int ring_timeout;
+       /*! Ring delay to use when this trunk is ringing on this specific
+        *  station.  This takes higher priority than a ring delay set at
+        *  the station level. */
+       unsigned int ring_delay;
+       /*! Mark used during reload processing */
+       unsigned int mark:1;
+};
+
+static struct ao2_container *sla_stations;
+static struct ao2_container *sla_trunks;
+
+static const char sla_registrar[] = "SLA";
+
+/*! \brief Event types that can be queued up for the SLA thread */
+enum sla_event_type {
+       /*! A station has put the call on hold */
+       SLA_EVENT_HOLD,
+       /*! The state of a dial has changed */
+       SLA_EVENT_DIAL_STATE,
+       /*! The state of a ringing trunk has changed */
+       SLA_EVENT_RINGING_TRUNK,
+};
+
+struct sla_event {
+       enum sla_event_type type;
+       struct sla_station *station;
+       struct sla_trunk_ref *trunk_ref;
+       AST_LIST_ENTRY(sla_event) entry;
+};
+
+/*! \brief A station that failed to be dialed
+ * \note Only used by the SLA thread. */
+struct sla_failed_station {
+       struct sla_station *station;
+       struct timeval last_try;
+       AST_LIST_ENTRY(sla_failed_station) entry;
+};
+
+/*! \brief A trunk that is ringing */
+struct sla_ringing_trunk {
+       struct sla_trunk *trunk;
+       /*! The time that this trunk started ringing */
+       struct timeval ring_begin;
+       AST_LIST_HEAD_NOLOCK(, sla_station_ref) timed_out_stations;
+       AST_LIST_ENTRY(sla_ringing_trunk) entry;
+};
+
+enum sla_station_hangup {
+       SLA_STATION_HANGUP_NORMAL,
+       SLA_STATION_HANGUP_TIMEOUT,
+};
+
+/*! \brief A station that is ringing */
+struct sla_ringing_station {
+       struct sla_station *station;
+       /*! The time that this station started ringing */
+       struct timeval ring_begin;
+       AST_LIST_ENTRY(sla_ringing_station) entry;
+};
+
+/*!
+ * \brief A structure for data used by the sla thread
+ */
+static struct {
+       /*! The SLA thread ID */
+       pthread_t thread;
+       ast_cond_t cond;
+       ast_mutex_t lock;
+       AST_LIST_HEAD_NOLOCK(, sla_ringing_trunk) ringing_trunks;
+       AST_LIST_HEAD_NOLOCK(, sla_ringing_station) ringing_stations;
+       AST_LIST_HEAD_NOLOCK(, sla_failed_station) failed_stations;
+       AST_LIST_HEAD_NOLOCK(, sla_event) event_q;
+       unsigned int stop:1;
+       /*! Attempt to handle CallerID, even though it is known not to work
+        *  properly in some situations. */
+       unsigned int attempt_callerid:1;
+} sla = {
+       .thread = AST_PTHREADT_NULL,
+};
+
+static const char *sla_hold_str(unsigned int hold_access)
+{
+       const char *hold = "Unknown";
+
+       switch (hold_access) {
+       case SLA_HOLD_OPEN:
+               hold = "Open";
+               break;
+       case SLA_HOLD_PRIVATE:
+               hold = "Private";
+       default:
+               break;
+       }
+
+       return hold;
+}
+
+static char *sla_show_trunks(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
+{
+       struct ao2_iterator i;
+       struct sla_trunk *trunk;
+
+       switch (cmd) {
+       case CLI_INIT:
+               e->command = "sla show trunks";
+               e->usage =
+                       "Usage: sla show trunks\n"
+                       "       This will list all trunks defined in sla.conf\n";
+               return NULL;
+       case CLI_GENERATE:
+               return NULL;
+       }
+
+       ast_cli(a->fd, "\n"
+                   "=============================================================\n"
+                   "=== Configured SLA Trunks ===================================\n"
+                   "=============================================================\n"
+                   "===\n");
+       i = ao2_iterator_init(sla_trunks, 0);
+       for (; (trunk = ao2_iterator_next(&i)); ao2_ref(trunk, -1)) {
+               struct sla_station_ref *station_ref;
+               char ring_timeout[23] = "(none)";
+
+               ao2_lock(trunk);
+
+               if (trunk->ring_timeout) {
+                       snprintf(ring_timeout, sizeof(ring_timeout), "%u Seconds", trunk->ring_timeout);
+               }
+
+               ast_cli(a->fd, "=== ---------------------------------------------------------\n"
+                           "=== Trunk Name:       %s\n"
+                           "=== ==> Device:       %s\n"
+                           "=== ==> AutoContext:  %s\n"
+                           "=== ==> RingTimeout:  %s\n"
+                           "=== ==> BargeAllowed: %s\n"
+                           "=== ==> HoldAccess:   %s\n"
+                           "=== ==> Stations ...\n",
+                           trunk->name, trunk->device,
+                           S_OR(trunk->autocontext, "(none)"),
+                           ring_timeout,
+                           trunk->barge_disabled ? "No" : "Yes",
+                           sla_hold_str(trunk->hold_access));
+
+               AST_LIST_TRAVERSE(&trunk->stations, station_ref, entry) {
+                       ast_cli(a->fd, "===    ==> Station name: %s\n", station_ref->station->name);
+               }
+
+               ast_cli(a->fd, "=== ---------------------------------------------------------\n===\n");
+
+               ao2_unlock(trunk);
+       }
+       ao2_iterator_destroy(&i);
+       ast_cli(a->fd, "=============================================================\n\n");
+
+       return CLI_SUCCESS;
+}
+
+static const char *trunkstate2str(enum sla_trunk_state state)
+{
+#define S(e) case e: return # e;
+       switch (state) {
+       S(SLA_TRUNK_STATE_IDLE)
+       S(SLA_TRUNK_STATE_RINGING)
+       S(SLA_TRUNK_STATE_UP)
+       S(SLA_TRUNK_STATE_ONHOLD)
+       S(SLA_TRUNK_STATE_ONHOLD_BYME)
+       }
+       return "Uknown State";
+#undef S
+}
+
+static char *sla_show_stations(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
+{
+       struct ao2_iterator i;
+       struct sla_station *station;
+
+       switch (cmd) {
+       case CLI_INIT:
+               e->command = "sla show stations";
+               e->usage =
+                       "Usage: sla show stations\n"
+                       "       This will list all stations defined in sla.conf\n";
+               return NULL;
+       case CLI_GENERATE:
+               return NULL;
+       }
+
+       ast_cli(a->fd, "\n"
+                   "=============================================================\n"
+                   "=== Configured SLA Stations =================================\n"
+                   "=============================================================\n"
+                   "===\n");
+       i = ao2_iterator_init(sla_stations, 0);
+       for (; (station = ao2_iterator_next(&i)); ao2_ref(station, -1)) {
+               struct sla_trunk_ref *trunk_ref;
+               char ring_timeout[16] = "(none)";
+               char ring_delay[16] = "(none)";
+
+               ao2_lock(station);
+
+               if (station->ring_timeout) {
+                       snprintf(ring_timeout, sizeof(ring_timeout), "%u", station->ring_timeout);
+               }
+               if (station->ring_delay) {
+                       snprintf(ring_delay, sizeof(ring_delay), "%u", station->ring_delay);
+               }
+               ast_cli(a->fd, "=== ---------------------------------------------------------\n"
+                           "=== Station Name:    %s\n"
+                           "=== ==> Device:      %s\n"
+                           "=== ==> AutoContext: %s\n"
+                           "=== ==> RingTimeout: %s\n"
+                           "=== ==> RingDelay:   %s\n"
+                           "=== ==> HoldAccess:  %s\n"
+                           "=== ==> Trunks ...\n",
+                           station->name, station->device,
+                           S_OR(station->autocontext, "(none)"),
+                           ring_timeout, ring_delay,
+                           sla_hold_str(station->hold_access));
+               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+                       if (trunk_ref->ring_timeout) {
+                               snprintf(ring_timeout, sizeof(ring_timeout), "%u", trunk_ref->ring_timeout);
+                       } else {
+                               strcpy(ring_timeout, "(none)");
+                       }
+                       if (trunk_ref->ring_delay) {
+                               snprintf(ring_delay, sizeof(ring_delay), "%u", trunk_ref->ring_delay);
+                       } else {
+                               strcpy(ring_delay, "(none)");
+                       }
+
+                       ast_cli(a->fd, "===    ==> Trunk Name: %s\n"
+                   "===       ==> State:       %s\n"
+                   "===       ==> RingTimeout: %s\n"
+                   "===       ==> RingDelay:   %s\n",
+                   trunk_ref->trunk->name,
+                   trunkstate2str(trunk_ref->state),
+                   ring_timeout, ring_delay);
+               }
+               ast_cli(a->fd, "=== ---------------------------------------------------------\n"
+                           "===\n");
+
+               ao2_unlock(station);
+       }
+       ao2_iterator_destroy(&i);
+       ast_cli(a->fd, "============================================================\n"
+                   "\n");
+
+       return CLI_SUCCESS;
+}
+
+static struct ast_cli_entry cli_sla[] = {
+       AST_CLI_DEFINE(sla_show_trunks, "Show SLA Trunks"),
+       AST_CLI_DEFINE(sla_show_stations, "Show SLA Stations"),
+};
+
+static void sla_queue_event_full(enum sla_event_type type, struct sla_trunk_ref *trunk_ref, struct sla_station *station, int lock)
+{
+       struct sla_event *event;
+
+       if (sla.thread == AST_PTHREADT_NULL) {
+               ao2_ref(station, -1);
+               ao2_ref(trunk_ref, -1);
+               return;
+       }
+
+       if (!(event = ast_calloc(1, sizeof(*event)))) {
+               ao2_ref(station, -1);
+               ao2_ref(trunk_ref, -1);
+               return;
+       }
+
+       event->type = type;
+       event->trunk_ref = trunk_ref;
+       event->station = station;
+
+       if (!lock) {
+               AST_LIST_INSERT_TAIL(&sla.event_q, event, entry);
+               return;
+       }
+
+       ast_mutex_lock(&sla.lock);
+       AST_LIST_INSERT_TAIL(&sla.event_q, event, entry);
+       ast_cond_signal(&sla.cond);
+       ast_mutex_unlock(&sla.lock);
+}
+
+static void sla_queue_event_nolock(enum sla_event_type type)
+{
+       sla_queue_event_full(type, NULL, NULL, 0);
+}
+
+static void sla_queue_event(enum sla_event_type type)
+{
+       sla_queue_event_full(type, NULL, NULL, 1);
+}
+
+/*! \brief Queue a SLA event from the conference */
+static void sla_queue_event_conf(enum sla_event_type type, struct ast_channel *chan, const char *confname)
+{
+       struct sla_station *station;
+       struct sla_trunk_ref *trunk_ref = NULL;
+       char *trunk_name;
+       struct ao2_iterator i;
+
+       trunk_name = ast_strdupa(confname);
+       strsep(&trunk_name, "_");
+       if (ast_strlen_zero(trunk_name)) {
+               ast_log(LOG_ERROR, "Invalid conference name for SLA - '%s'!\n", confname);
+               return;
+       }
+
+       i = ao2_iterator_init(sla_stations, 0);
+       while ((station = ao2_iterator_next(&i))) {
+               ao2_lock(station);
+               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+                       if (trunk_ref->chan == chan && !strcmp(trunk_ref->trunk->name, trunk_name)) {
+                               ao2_ref(trunk_ref, 1);
+                               break;
+                       }
+               }
+               ao2_unlock(station);
+               if (trunk_ref) {
+                       /* station reference given to sla_queue_event_full() */
+                       break;
+               }
+               ao2_ref(station, -1);
+       }
+       ao2_iterator_destroy(&i);
+
+       if (!trunk_ref) {
+               ast_debug(1, "Trunk not found for event!\n");
+               return;
+       }
+
+       sla_queue_event_full(type, trunk_ref, station, 1);
+}
+
+/*!
+ * \brief Framehook to support HOLD within the conference
+ */
+
+struct sla_framehook_data {
+       int framehook_id;
+       char *confname;
+};
+
+static const struct ast_datastore_info sla_framehook_datastore = {
+       .type = "app_sla",
+};
+
+static int remove_framehook(struct ast_channel *chan)
+{
+       struct ast_datastore *datastore = NULL;
+       struct sla_framehook_data *data;
+       SCOPED_CHANNELLOCK(chan_lock, chan);
+
+       datastore = ast_channel_datastore_find(chan, &sla_framehook_datastore, NULL);
+       if (!datastore) {
+               ast_log(AST_LOG_WARNING, "Cannot remove framehook from %s: HOLD_INTERCEPT not currently enabled\n", ast_channel_name(chan));
+               return -1;
+       }
+       data = datastore->data;
+
+       ast_free(data->confname);
+
+       if (ast_framehook_detach(chan, data->framehook_id)) {
+               ast_log(AST_LOG_WARNING, "Failed to remove framehook from channel %s\n", ast_channel_name(chan));
+               return -1;
+       }
+       if (ast_channel_datastore_remove(chan, datastore)) {
+               ast_log(AST_LOG_WARNING, "Failed to remove datastore from channel %s\n", ast_channel_name(chan));
+               return -1;
+       }
+       ast_datastore_free(datastore);
+
+       return 0;
+}
+
+static struct ast_frame *sla_framehook(struct ast_channel *chan, struct ast_frame *f, enum ast_framehook_event event, void *data)
+{
+       struct sla_framehook_data *sla_data = data;
+       if (!f || (event != AST_FRAMEHOOK_EVENT_WRITE)) {
+               return f;
+       }
+       if (f->frametype == AST_FRAME_CONTROL && f->subclass.integer == AST_CONTROL_HOLD) {
+               sla_queue_event_conf(SLA_EVENT_HOLD, chan, sla_data->confname);
+       }
+       return f;
+}
+
+/*! \brief Callback function which informs upstream if we are consuming a frame of a specific type */
+static int sla_framehook_consume(void *data, enum ast_frame_type type)
+{
+       return (type == AST_FRAME_CONTROL ? 1 : 0);
+}
+
+static int attach_framehook(struct ast_channel *chan, const char *confname)
+{
+       struct ast_datastore *datastore;
+       struct sla_framehook_data *data;
+       static struct ast_framehook_interface sla_framehook_interface = {
+               .version = AST_FRAMEHOOK_INTERFACE_VERSION,
+               .event_cb = sla_framehook,
+               .consume_cb = sla_framehook_consume,
+               .disable_inheritance = 1,
+       };
+       SCOPED_CHANNELLOCK(chan_lock, chan);
+
+       datastore = ast_channel_datastore_find(chan, &sla_framehook_datastore, NULL);
+       if (datastore) {
+               ast_log(AST_LOG_WARNING, "SLA framehook already set on '%s'\n", ast_channel_name(chan));
+               return 0;
+       }
+
+       datastore = ast_datastore_alloc(&sla_framehook_datastore, NULL);
+       if (!datastore) {
+               return -1;
+       }
+
+       data = ast_calloc(1, sizeof(*data));
+       if (!data) {
+               ast_datastore_free(datastore);
+               return -1;
+       }
+
+       data->framehook_id = ast_framehook_attach(chan, &sla_framehook_interface);
+       data->confname = ast_strdup(confname);
+       if (!data->confname || data->framehook_id < 0) {
+               ast_log(AST_LOG_WARNING, "Failed to attach SLA framehook to '%s'\n", ast_channel_name(chan));
+               ast_datastore_free(datastore);
+               ast_free(data);
+               return -1;
+       }
+       datastore->data = data;
+
+       ast_channel_datastore_add(chan, datastore);
+       return 0;
+}
+
+/*!
+ * \internal
+ * \brief Find an SLA trunk by name
+ */
+static struct sla_trunk *sla_find_trunk(const char *name)
+{
+       struct sla_trunk tmp_trunk = {
+               .name = name,
+       };
+
+       return ao2_find(sla_trunks, &tmp_trunk, OBJ_POINTER);
+}
+
+/*!
+ * \internal
+ * \brief Find an SLA station by name
+ */
+static struct sla_station *sla_find_station(const char *name)
+{
+       struct sla_station tmp_station = {
+               .name = name,
+       };
+
+       return ao2_find(sla_stations, &tmp_station, OBJ_POINTER);
+}
+
+static int sla_check_station_hold_access(const struct sla_trunk *trunk, const struct sla_station *station)
+{
+       struct sla_station_ref *station_ref;
+       struct sla_trunk_ref *trunk_ref;
+
+       /* For each station that has this call on hold, check for private hold. */
+       AST_LIST_TRAVERSE(&trunk->stations, station_ref, entry) {
+               AST_LIST_TRAVERSE(&station_ref->station->trunks, trunk_ref, entry) {
+                       if (trunk_ref->trunk != trunk || station_ref->station == station) {
+                               continue;
+                       }
+                       if (trunk_ref->state == SLA_TRUNK_STATE_ONHOLD_BYME && station_ref->station->hold_access == SLA_HOLD_PRIVATE) {
+                               return 1;
+                       }
+                       return 0;
+               }
+       }
+
+       return 0;
+}
+
+/*!
+ * \brief Find a trunk reference on a station by name
+ * \param station the station
+ * \param name the trunk's name
+ * \pre sla_station is locked
+ * \return a pointer to the station's trunk reference.  If the trunk
+ *         is not found, it is not idle and barge is disabled, or if
+ *         it is on hold and private hold is set, then NULL will be returned.
+ */
+static struct sla_trunk_ref *sla_find_trunk_ref_byname(const struct sla_station *station, const char *name)
+{
+       struct sla_trunk_ref *trunk_ref = NULL;
+
+       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+               if (strcasecmp(trunk_ref->trunk->name, name)) {
+                       continue;
+               }
+
+               if (trunk_ref->trunk->barge_disabled && trunk_ref->state == SLA_TRUNK_STATE_UP) {
+                       ast_debug(2, "Barge disabled, trunk not available\n");
+                       trunk_ref = NULL;
+               } else if (trunk_ref->trunk->hold_stations && trunk_ref->trunk->hold_access == SLA_HOLD_PRIVATE && trunk_ref->state != SLA_TRUNK_STATE_ONHOLD_BYME) {
+                       ast_debug(2, "Private hold by another station\n");
+                       trunk_ref = NULL;
+               } else if (sla_check_station_hold_access(trunk_ref->trunk, station)) {
+                       ast_debug(2, "No hold access\n");
+                       trunk_ref = NULL;
+               }
+
+               break;
+       }
+
+       if (trunk_ref) {
+               ao2_ref(trunk_ref, 1);
+       }
+
+       return trunk_ref;
+}
+
+static void sla_station_ref_destructor(void *obj)
+{
+       struct sla_station_ref *station_ref = obj;
+
+       if (station_ref->station) {
+               ao2_ref(station_ref->station, -1);
+               station_ref->station = NULL;
+       }
+}
+
+static struct sla_station_ref *sla_create_station_ref(struct sla_station *station)
+{
+       struct sla_station_ref *station_ref;
+
+       if (!(station_ref = ao2_alloc(sizeof(*station_ref), sla_station_ref_destructor))) {
+               return NULL;
+       }
+
+       ao2_ref(station, 1);
+       station_ref->station = station;
+
+       return station_ref;
+}
+
+static struct sla_ringing_station *sla_create_ringing_station(struct sla_station *station)
+{
+       struct sla_ringing_station *ringing_station;
+
+       if (!(ringing_station = ast_calloc(1, sizeof(*ringing_station)))) {
+               return NULL;
+       }
+
+       ao2_ref(station, 1);
+       ringing_station->station = station;
+       ringing_station->ring_begin = ast_tvnow();
+
+       return ringing_station;
+}
+
+static void sla_ringing_station_destroy(struct sla_ringing_station *ringing_station)
+{
+       if (ringing_station->station) {
+               ao2_ref(ringing_station->station, -1);
+               ringing_station->station = NULL;
+       }
+
+       ast_free(ringing_station);
+}
+
+static struct sla_failed_station *sla_create_failed_station(struct sla_station *station)
+{
+       struct sla_failed_station *failed_station;
+
+       if (!(failed_station = ast_calloc(1, sizeof(*failed_station)))) {
+               return NULL;
+       }
+
+       ao2_ref(station, 1);
+       failed_station->station = station;
+       failed_station->last_try = ast_tvnow();
+
+       return failed_station;
+}
+
+static void sla_failed_station_destroy(struct sla_failed_station *failed_station)
+{
+       if (failed_station->station) {
+               ao2_ref(failed_station->station, -1);
+               failed_station->station = NULL;
+       }
+
+       ast_free(failed_station);
+}
+
+static enum ast_device_state sla_state_to_devstate(enum sla_trunk_state state)
+{
+       switch (state) {
+       case SLA_TRUNK_STATE_IDLE:
+               return AST_DEVICE_NOT_INUSE;
+       case SLA_TRUNK_STATE_RINGING:
+               return AST_DEVICE_RINGING;
+       case SLA_TRUNK_STATE_UP:
+               return AST_DEVICE_INUSE;
+       case SLA_TRUNK_STATE_ONHOLD:
+       case SLA_TRUNK_STATE_ONHOLD_BYME:
+               return AST_DEVICE_ONHOLD;
+       }
+
+       return AST_DEVICE_UNKNOWN;
+}
+
+static void sla_change_trunk_state(const struct sla_trunk *trunk, enum sla_trunk_state state,
+       enum sla_which_trunk_refs inactive_only, const struct sla_trunk_ref *exclude)
+{
+       struct sla_station *station;
+       struct sla_trunk_ref *trunk_ref;
+       struct ao2_iterator i;
+
+       i = ao2_iterator_init(sla_stations, 0);
+       while ((station = ao2_iterator_next(&i))) {
+               ao2_lock(station);
+               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+                       if (trunk_ref->trunk != trunk || (inactive_only ? trunk_ref->chan : 0) || trunk_ref == exclude) {
+                               continue;
+                       }
+                       trunk_ref->state = state;
+                       ast_devstate_changed(sla_state_to_devstate(state), AST_DEVSTATE_CACHABLE, "SLA:%s_%s", station->name, trunk->name);
+                       break;
+               }
+               ao2_unlock(station);
+               ao2_ref(station, -1);
+       }
+       ao2_iterator_destroy(&i);
+}
+
+struct run_station_args {
+       struct sla_station *station;
+       struct sla_trunk_ref *trunk_ref;
+       ast_mutex_t *cond_lock;
+       ast_cond_t *cond;
+};
+
+static void answer_trunk_chan(struct ast_channel *chan)
+{
+       ast_raw_answer(chan); /* Do NOT use ast_answer since that waits for media using ast_waitfor_nandfds. */
+       ast_indicate(chan, -1);
+}
+
+static int conf_run(struct ast_channel *chan, const char *confname, struct ast_flags *confflags, char *optargs[])
+{
+       char confbridge_args[256];
+       int res = 0;
+
+       snprintf(confbridge_args, sizeof(confbridge_args), "%s", confname);
+
+       res |= ast_func_write(chan, "CONFBRIDGE(user,quiet)", ast_test_flag(confflags, CONFFLAG_QUIET) ? "1" : "0");
+       res |= ast_func_write(chan, "CONFBRIDGE(user,dtmf_passthrough)", ast_test_flag(confflags, CONFFLAG_PASS_DTMF) ? "1" : "0");
+       res |= ast_func_write(chan, "CONFBRIDGE(user,marked)", ast_test_flag(confflags, CONFFLAG_MARKEDUSER) ? "1" : "0");
+       res |= ast_func_write(chan, "CONFBRIDGE(user,end_marked)", ast_test_flag(confflags, CONFFLAG_MARKEDEXIT) ? "1" : "0");
+       res |= ast_func_write(chan, "CONFBRIDGE(user,music_on_hold_when_empty)", ast_test_flag(confflags, CONFFLAG_MOH) ? "1" : "0");
+       if (ast_test_flag(confflags, CONFFLAG_MOH) && !ast_strlen_zero(optargs[SLA_TRUNK_OPT_ARG_MOH_CLASS])) {
+               res |= ast_func_write(chan, "CONFBRIDGE(user,music_on_hold_class)", optargs[SLA_TRUNK_OPT_ARG_MOH_CLASS]);
+       }
+
+       if (res) {
+               ast_log(LOG_ERROR, "Failed to set up conference, aborting\n");
+               return -1;
+       }
+
+       /* Attach a framehook that we'll use to process HOLD from stations. */
+       if (ast_test_flag(confflags, CONFFLAG_SLA_STATION) && attach_framehook(chan, confname)) {
+               return -1;
+       }
+
+       ast_debug(2, "Channel %s is running ConfBridge(%s)\n", ast_channel_name(chan), confbridge_args);
+       res = ast_pbx_exec_application(chan, "ConfBridge", confbridge_args);
+
+       if (ast_test_flag(confflags, CONFFLAG_SLA_STATION)) {
+               remove_framehook(chan);
+       }
+       return res;
+}
+
+static int conf_kick_all(struct ast_channel *chan, const char *confname)
+{
+       char confkick_args[256];
+
+       snprintf(confkick_args, sizeof(confkick_args), "%s,all", confname);
+       ast_debug(2, "Kicking all participants from conference %s\n", confname);
+
+       if (chan) {
+               return ast_pbx_exec_application(chan, "ConfKick", confkick_args);
+       } else {
+               /* We might not have a channel available to us, use a dummy channel in that case. */
+               chan = ast_dummy_channel_alloc();
+               if (!chan) {
+                       ast_log(LOG_WARNING, "Failed to allocate dummy channel\n");
+                       return -1;
+               } else {
+                       int res = ast_pbx_exec_application(chan, "ConfKick", confkick_args);
+                       ast_channel_unref(chan);
+                       return res;
+               }
+       }
+}
+
+static void *run_station(void *data)
+{
+       RAII_VAR(struct sla_station *, station, NULL, ao2_cleanup);
+       RAII_VAR(struct sla_trunk_ref *, trunk_ref, NULL, ao2_cleanup);
+       struct ast_str *conf_name = ast_str_create(16);
+       struct ast_flags conf_flags = { 0 };
+
+       {
+               struct run_station_args *args = data;
+               station = args->station;
+               trunk_ref = args->trunk_ref;
+               ast_mutex_lock(args->cond_lock);
+               ast_cond_signal(args->cond);
+               ast_mutex_unlock(args->cond_lock);
+               /* args is no longer valid here. */
+       }
+
+       ast_atomic_fetchadd_int((int *) &trunk_ref->trunk->active_stations, 1);
+       ast_str_set(&conf_name, 0, "SLA_%s", trunk_ref->trunk->name);
+       ast_set_flag(&conf_flags, CONFFLAG_QUIET | CONFFLAG_MARKEDEXIT | CONFFLAG_PASS_DTMF | CONFFLAG_SLA_STATION);
+       answer_trunk_chan(trunk_ref->chan);
+
+       ast_debug(2, "Station %s joining conference %s\n", station->name, ast_str_buffer(conf_name));
+       conf_run(trunk_ref->chan, ast_str_buffer(conf_name), &conf_flags, NULL);
+
+       trunk_ref->chan = NULL;
+       if (ast_atomic_dec_and_test((int *) &trunk_ref->trunk->active_stations) &&
+               trunk_ref->state != SLA_TRUNK_STATE_ONHOLD_BYME) {
+               conf_kick_all(NULL, ast_str_buffer(conf_name));
+               trunk_ref->trunk->hold_stations = 0;
+               sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
+       }
+
+       ast_dial_join(station->dial);
+       ast_dial_destroy(station->dial);
+       station->dial = NULL;
+       ast_free(conf_name);
+
+       return NULL;
+}
+
+static void sla_ringing_trunk_destroy(struct sla_ringing_trunk *ringing_trunk);
+
+static void sla_stop_ringing_trunk(struct sla_ringing_trunk *ringing_trunk)
+{
+       struct sla_station_ref *station_ref;
+
+       conf_kick_all(ringing_trunk->trunk->chan, ringing_trunk->trunk->name);
+       sla_change_trunk_state(ringing_trunk->trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
+
+       while ((station_ref = AST_LIST_REMOVE_HEAD(&ringing_trunk->timed_out_stations, entry))) {
+               ao2_ref(station_ref, -1);
+       }
+
+       sla_ringing_trunk_destroy(ringing_trunk);
+}
+
+static void sla_stop_ringing_station(struct sla_ringing_station *ringing_station, enum sla_station_hangup hangup)
+{
+       struct sla_ringing_trunk *ringing_trunk;
+       struct sla_trunk_ref *trunk_ref;
+       struct sla_station_ref *station_ref;
+
+       ast_dial_join(ringing_station->station->dial);
+       ast_dial_destroy(ringing_station->station->dial);
+       ringing_station->station->dial = NULL;
+
+       if (hangup == SLA_STATION_HANGUP_NORMAL) {
+               goto done;
+       }
+
+       /* If the station is being hung up because of a timeout, then add it to the
+        * list of timed out stations on each of the ringing trunks.  This is so
+        * that when doing further processing to figure out which stations should be
+        * ringing, which trunk to answer, determining timeouts, etc., we know which
+        * ringing trunks we should ignore. */
+       AST_LIST_TRAVERSE(&sla.ringing_trunks, ringing_trunk, entry) {
+               AST_LIST_TRAVERSE(&ringing_station->station->trunks, trunk_ref, entry) {
+                       if (ringing_trunk->trunk == trunk_ref->trunk) {
+                               break;
+                       }
+               }
+               if (!trunk_ref) {
+                       continue;
+               }
+               if (!(station_ref = sla_create_station_ref(ringing_station->station))) {
+                       continue;
+               }
+               AST_LIST_INSERT_TAIL(&ringing_trunk->timed_out_stations, station_ref, entry);
+       }
+
+done:
+       sla_ringing_station_destroy(ringing_station);
+}
+
+static void sla_dial_state_callback(struct ast_dial *dial)
+{
+       sla_queue_event(SLA_EVENT_DIAL_STATE);
+}
+
+/*! \brief Check to see if dialing this station already timed out for this ringing trunk
+ * \note Assumes sla.lock is locked
+ */
+static int sla_check_timed_out_station(const struct sla_ringing_trunk *ringing_trunk, const struct sla_station *station)
+{
+       struct sla_station_ref *timed_out_station;
+
+       AST_LIST_TRAVERSE(&ringing_trunk->timed_out_stations, timed_out_station, entry) {
+               if (station == timed_out_station->station) {
+                       return 1;
+               }
+       }
+
+       return 0;
+}
+
+/*! \brief Choose the highest priority ringing trunk for a station
+ * \param station the station
+ * \param rm remove the ringing trunk once selected
+ * \param trunk_ref a place to store the pointer to this stations reference to
+ *        the selected trunk
+ * \return a pointer to the selected ringing trunk, or NULL if none found
+ * \note Assumes that sla.lock is locked
+ */
+static struct sla_ringing_trunk *sla_choose_ringing_trunk(struct sla_station *station, struct sla_trunk_ref **trunk_ref, int rm)
+{
+       struct sla_trunk_ref *s_trunk_ref;
+       struct sla_ringing_trunk *ringing_trunk = NULL;
+
+       AST_LIST_TRAVERSE(&station->trunks, s_trunk_ref, entry) {
+               AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_trunks, ringing_trunk, entry) {
+                       /* Make sure this is the trunk we're looking for */
+                       if (s_trunk_ref->trunk != ringing_trunk->trunk) {
+                               continue;
+                       }
+
+                       /* This trunk on the station is ringing.  But, make sure this station
+                        * didn't already time out while this trunk was ringing. */
+                       if (sla_check_timed_out_station(ringing_trunk, station)) {
+                               continue;
+                       }
+
+                       if (rm) {
+                               AST_LIST_REMOVE_CURRENT(entry);
+                       }
+
+                       if (trunk_ref) {
+                               ao2_ref(s_trunk_ref, 1);
+                               *trunk_ref = s_trunk_ref;
+                       }
+
+                       break;
+               }
+               AST_LIST_TRAVERSE_SAFE_END;
+
+               if (ringing_trunk) {
+                       break;
+               }
+       }
+
+       return ringing_trunk;
+}
+
+static void sla_handle_dial_state_event(void)
+{
+       struct sla_ringing_station *ringing_station;
+
+       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_stations, ringing_station, entry) {
+               RAII_VAR(struct sla_trunk_ref *, s_trunk_ref, NULL, ao2_cleanup);
+               struct sla_ringing_trunk *ringing_trunk = NULL;
+               struct run_station_args args;
+               enum ast_dial_result dial_res;
+               pthread_t dont_care;
+               ast_mutex_t cond_lock;
+               ast_cond_t cond;
+
+               switch ((dial_res = ast_dial_state(ringing_station->station->dial))) {
+               case AST_DIAL_RESULT_HANGUP:
+               case AST_DIAL_RESULT_INVALID:
+               case AST_DIAL_RESULT_FAILED:
+               case AST_DIAL_RESULT_TIMEOUT:
+               case AST_DIAL_RESULT_UNANSWERED:
+                       AST_LIST_REMOVE_CURRENT(entry);
+                       sla_stop_ringing_station(ringing_station, SLA_STATION_HANGUP_NORMAL);
+                       break;
+               case AST_DIAL_RESULT_ANSWERED:
+                       AST_LIST_REMOVE_CURRENT(entry);
+                       /* Find the appropriate trunk to answer. */
+                       ast_mutex_lock(&sla.lock);
+                       ringing_trunk = sla_choose_ringing_trunk(ringing_station->station, &s_trunk_ref, 1);
+                       ast_mutex_unlock(&sla.lock);
+                       if (!ringing_trunk) {
+                               /* This case happens in a bit of a race condition.  If two stations answer
+                                * the outbound call at the same time, the first one will get connected to
+                                * the trunk.  When the second one gets here, it will not see any trunks
+                                * ringing so we have no idea what to conect it to.  So, we just hang up
+                                * on it. */
+                               ast_debug(1, "Found no ringing trunk for station '%s' to answer!\n", ringing_station->station->name);
+                               ast_dial_join(ringing_station->station->dial);
+                               ast_dial_destroy(ringing_station->station->dial);
+                               ringing_station->station->dial = NULL;
+                               sla_ringing_station_destroy(ringing_station);
+                               break;
+                       }
+                       /* Track the channel that answered this trunk */
+                       s_trunk_ref->chan = ast_dial_answered(ringing_station->station->dial);
+                       /* Actually answer the trunk */
+                       answer_trunk_chan(ringing_trunk->trunk->chan);
+                       sla_change_trunk_state(ringing_trunk->trunk, SLA_TRUNK_STATE_UP, ALL_TRUNK_REFS, NULL);
+                       /* Now, start a thread that will connect this station to the trunk.  The rest of
+                        * the code here sets up the thread and ensures that it is able to save the arguments
+                        * before they are no longer valid since they are allocated on the stack. */
+                       ao2_ref(s_trunk_ref, 1);
+                       args.trunk_ref = s_trunk_ref;
+                       ao2_ref(ringing_station->station, 1);
+                       args.station = ringing_station->station;
+                       args.cond = &cond;
+                       args.cond_lock = &cond_lock;
+                       sla_ringing_trunk_destroy(ringing_trunk);
+                       sla_ringing_station_destroy(ringing_station);
+                       ast_mutex_init(&cond_lock);
+                       ast_cond_init(&cond, NULL);
+                       ast_mutex_lock(&cond_lock);
+                       ast_pthread_create_detached_background(&dont_care, NULL, run_station, &args);
+                       ast_cond_wait(&cond, &cond_lock);
+                       ast_mutex_unlock(&cond_lock);
+                       ast_mutex_destroy(&cond_lock);
+                       ast_cond_destroy(&cond);
+                       break;
+               case AST_DIAL_RESULT_TRYING:
+               case AST_DIAL_RESULT_RINGING:
+               case AST_DIAL_RESULT_PROGRESS:
+               case AST_DIAL_RESULT_PROCEEDING:
+                       break;
+               }
+               if (dial_res == AST_DIAL_RESULT_ANSWERED) {
+                       /* Queue up reprocessing ringing trunks, and then ringing stations again */
+                       sla_queue_event(SLA_EVENT_RINGING_TRUNK);
+                       sla_queue_event(SLA_EVENT_DIAL_STATE);
+                       break;
+               }
+       }
+       AST_LIST_TRAVERSE_SAFE_END;
+}
+
+/*! \brief Check to see if this station is already ringing
+ * \note Assumes sla.lock is locked
+ */
+static int sla_check_ringing_station(const struct sla_station *station)
+{
+       struct sla_ringing_station *ringing_station;
+
+       AST_LIST_TRAVERSE(&sla.ringing_stations, ringing_station, entry) {
+               if (station == ringing_station->station) {
+                       return 1;
+               }
+       }
+
+       return 0;
+}
+
+/*! \brief Check to see if this station has failed to be dialed in the past minute
+ * \note assumes sla.lock is locked
+ */
+static int sla_check_failed_station(const struct sla_station *station)
+{
+       struct sla_failed_station *failed_station;
+       int res = 0;
+
+       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.failed_stations, failed_station, entry) {
+               if (station != failed_station->station) {
+                       continue;
+               }
+               if (ast_tvdiff_ms(ast_tvnow(), failed_station->last_try) > 1000) {
+                       AST_LIST_REMOVE_CURRENT(entry);
+                       sla_failed_station_destroy(failed_station);
+                       break;
+               }
+               res = 1;
+       }
+       AST_LIST_TRAVERSE_SAFE_END
+
+       return res;
+}
+
+/*! \brief Ring a station
+ * \note Assumes sla.lock is locked
+ */
+static int sla_ring_station(struct sla_ringing_trunk *ringing_trunk, struct sla_station *station)
+{
+       char *tech, *tech_data;
+       struct ast_dial *dial;
+       struct sla_ringing_station *ringing_station;
+       enum ast_dial_result res;
+       int caller_is_saved;
+       struct ast_party_caller caller;
+
+       if (!(dial = ast_dial_create())) {
+               return -1;
+       }
+
+       ast_dial_set_state_callback(dial, sla_dial_state_callback);
+       tech_data = ast_strdupa(station->device);
+       tech = strsep(&tech_data, "/");
+
+       if (ast_dial_append(dial, tech, tech_data, NULL) == -1) {
+               ast_dial_destroy(dial);
+               return -1;
+       }
+
+       /* Do we need to save off the caller ID data? */
+       caller_is_saved = 0;
+       if (!sla.attempt_callerid) {
+               caller_is_saved = 1;
+               caller = *ast_channel_caller(ringing_trunk->trunk->chan);
+               ast_party_caller_init(ast_channel_caller(ringing_trunk->trunk->chan));
+       }
+
+       res = ast_dial_run(dial, ringing_trunk->trunk->chan, 1);
+
+       /* Restore saved caller ID */
+       if (caller_is_saved) {
+               ast_party_caller_free(ast_channel_caller(ringing_trunk->trunk->chan));
+               ast_channel_caller_set(ringing_trunk->trunk->chan, &caller);
+       }
+
+       if (res != AST_DIAL_RESULT_TRYING) {
+               struct sla_failed_station *failed_station;
+               ast_dial_destroy(dial);
+               if ((failed_station = sla_create_failed_station(station))) {
+                       AST_LIST_INSERT_HEAD(&sla.failed_stations, failed_station, entry);
+               }
+               return -1;
+       }
+       if (!(ringing_station = sla_create_ringing_station(station))) {
+               ast_dial_join(dial);
+               ast_dial_destroy(dial);
+               return -1;
+       }
+
+       station->dial = dial;
+
+       AST_LIST_INSERT_HEAD(&sla.ringing_stations, ringing_station, entry);
+
+       return 0;
+}
+
+/*! \brief Check to see if a station is in use
+ */
+static int sla_check_inuse_station(const struct sla_station *station)
+{
+       struct sla_trunk_ref *trunk_ref;
+
+       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+               if (trunk_ref->chan) {
+                       return 1;
+               }
+       }
+
+       return 0;
+}
+
+static struct sla_trunk_ref *sla_find_trunk_ref(const struct sla_station *station, const struct sla_trunk *trunk)
+{
+       struct sla_trunk_ref *trunk_ref = NULL;
+
+       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+               if (trunk_ref->trunk == trunk) {
+                       break;
+               }
+       }
+
+       ao2_ref(trunk_ref, 1);
+
+       return trunk_ref;
+}
+
+/*! \brief Calculate the ring delay for a given ringing trunk on a station
+ * \param station the station
+ * \param ringing_trunk the trunk.  If NULL, the highest priority ringing trunk will be used
+ * \return the number of ms left before the delay is complete, or INT_MAX if there is no delay
+ */
+static int sla_check_station_delay(struct sla_station *station, struct sla_ringing_trunk *ringing_trunk)
+{
+       RAII_VAR(struct sla_trunk_ref *, trunk_ref, NULL, ao2_cleanup);
+       unsigned int delay = UINT_MAX;
+       int time_left, time_elapsed;
+
+       if (!ringing_trunk) {
+               ringing_trunk = sla_choose_ringing_trunk(station, &trunk_ref, 0);
+       } else {
+               trunk_ref = sla_find_trunk_ref(station, ringing_trunk->trunk);
+       }
+
+       if (!ringing_trunk || !trunk_ref) {
+               return delay;
+       }
+
+       /* If this station has a ring delay specific to the highest priority
+        * ringing trunk, use that.  Otherwise, use the ring delay specified
+        * globally for the station. */
+       delay = trunk_ref->ring_delay;
+       if (!delay) {
+               delay = station->ring_delay;
+       }
+       if (!delay) {
+               return INT_MAX;
+       }
+
+       time_elapsed = ast_tvdiff_ms(ast_tvnow(), ringing_trunk->ring_begin);
+       time_left = (delay * 1000) - time_elapsed;
+
+       return time_left;
+}
+
+/*! \brief Ring stations based on current set of ringing trunks
+ * \note Assumes that sla.lock is locked
+ */
+static void sla_ring_stations(void)
+{
+       struct sla_station_ref *station_ref;
+       struct sla_ringing_trunk *ringing_trunk;
+
+       /* Make sure that every station that uses at least one of the ringing
+        * trunks, is ringing. */
+       AST_LIST_TRAVERSE(&sla.ringing_trunks, ringing_trunk, entry) {
+               AST_LIST_TRAVERSE(&ringing_trunk->trunk->stations, station_ref, entry) {
+                       int time_left;
+
+                       /* Is this station already ringing? */
+                       if (sla_check_ringing_station(station_ref->station)) {
+                               continue;
+                       }
+
+                       /* Is this station already in a call? */
+                       if (sla_check_inuse_station(station_ref->station)) {
+                               continue;
+                       }
+
+                       /* Did we fail to dial this station earlier?  If so, has it been
+                        * a minute since we tried? */
+                       if (sla_check_failed_station(station_ref->station)) {
+                               continue;
+                       }
+
+                       /* If this station already timed out while this trunk was ringing,
+                        * do not dial it again for this ringing trunk. */
+                       if (sla_check_timed_out_station(ringing_trunk, station_ref->station)) {
+                               continue;
+                       }
+
+                       /* Check for a ring delay in progress */
+                       time_left = sla_check_station_delay(station_ref->station, ringing_trunk);
+                       if (time_left != INT_MAX && time_left > 0) {
+                               continue;
+                       }
+
+                       /* It is time to make this station begin to ring.  Do it! */
+                       sla_ring_station(ringing_trunk, station_ref->station);
+               }
+       }
+       /* Now, all of the stations that should be ringing, are ringing. */
+}
+
+static void sla_hangup_stations(void)
+{
+       struct sla_trunk_ref *trunk_ref;
+       struct sla_ringing_station *ringing_station;
+
+       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_stations, ringing_station, entry) {
+               AST_LIST_TRAVERSE(&ringing_station->station->trunks, trunk_ref, entry) {
+                       struct sla_ringing_trunk *ringing_trunk;
+                       ast_mutex_lock(&sla.lock);
+                       AST_LIST_TRAVERSE(&sla.ringing_trunks, ringing_trunk, entry) {
+                               if (trunk_ref->trunk == ringing_trunk->trunk) {
+                                       break;
+                               }
+                       }
+                       ast_mutex_unlock(&sla.lock);
+                       if (ringing_trunk) {
+                               break;
+                       }
+               }
+               if (!trunk_ref) {
+                       AST_LIST_REMOVE_CURRENT(entry);
+                       ast_dial_join(ringing_station->station->dial);
+                       ast_dial_destroy(ringing_station->station->dial);
+                       ringing_station->station->dial = NULL;
+                       sla_ringing_station_destroy(ringing_station);
+               }
+       }
+       AST_LIST_TRAVERSE_SAFE_END
+}
+
+static void sla_handle_ringing_trunk_event(void)
+{
+       ast_mutex_lock(&sla.lock);
+       sla_ring_stations();
+       ast_mutex_unlock(&sla.lock);
+
+       /* Find stations that shouldn't be ringing anymore. */
+       sla_hangup_stations();
+}
+
+static void sla_handle_hold_event(struct sla_event *event)
+{
+       ast_atomic_fetchadd_int((int *) &event->trunk_ref->trunk->hold_stations, 1);
+       event->trunk_ref->state = SLA_TRUNK_STATE_ONHOLD_BYME;
+       ast_devstate_changed(AST_DEVICE_ONHOLD, AST_DEVSTATE_CACHABLE, "SLA:%s_%s", event->station->name, event->trunk_ref->trunk->name);
+       sla_change_trunk_state(event->trunk_ref->trunk, SLA_TRUNK_STATE_ONHOLD, INACTIVE_TRUNK_REFS, event->trunk_ref);
+
+       if (event->trunk_ref->trunk->active_stations == 1) {
+               /* The station putting it on hold is the only one on the call, so start
+                * Music on hold to the trunk. */
+               event->trunk_ref->trunk->on_hold = 1;
+               ast_indicate(event->trunk_ref->trunk->chan, AST_CONTROL_HOLD);
+       }
+
+       ast_softhangup(event->trunk_ref->chan, AST_SOFTHANGUP_DEV);
+       event->trunk_ref->chan = NULL;
+}
+
+/*! \brief Process trunk ring timeouts
+ * \note Called with sla.lock locked
+ * \return non-zero if a change to the ringing trunks was made
+ */
+static int sla_calc_trunk_timeouts(unsigned int *timeout)
+{
+       struct sla_ringing_trunk *ringing_trunk;
+       int res = 0;
+
+       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_trunks, ringing_trunk, entry) {
+               int time_left, time_elapsed;
+               if (!ringing_trunk->trunk->ring_timeout) {
+                       continue;
+               }
+               time_elapsed = ast_tvdiff_ms(ast_tvnow(), ringing_trunk->ring_begin);
+               time_left = (ringing_trunk->trunk->ring_timeout * 1000) - time_elapsed;
+               if (time_left <= 0) {
+                       pbx_builtin_setvar_helper(ringing_trunk->trunk->chan, "SLATRUNK_STATUS", "RINGTIMEOUT");
+                       AST_LIST_REMOVE_CURRENT(entry);
+                       sla_stop_ringing_trunk(ringing_trunk);
+                       res = 1;
+                       continue;
+               }
+               if (time_left < *timeout) {
+                       *timeout = time_left;
+               }
+       }
+       AST_LIST_TRAVERSE_SAFE_END;
+
+       return res;
+}
+
+/*! \brief Process station ring timeouts
+ * \note Called with sla.lock locked
+ * \return non-zero if a change to the ringing stations was made
+ */
+static int sla_calc_station_timeouts(unsigned int *timeout)
+{
+       struct sla_ringing_trunk *ringing_trunk;
+       struct sla_ringing_station *ringing_station;
+       int res = 0;
+
+       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_stations, ringing_station, entry) {
+               unsigned int ring_timeout = 0;
+               int time_elapsed, time_left = INT_MAX, final_trunk_time_left = INT_MIN;
+               struct sla_trunk_ref *trunk_ref;
+
+               /* If there are any ring timeouts specified for a specific trunk
+                * on the station, then use the highest per-trunk ring timeout.
+                * Otherwise, use the ring timeout set for the entire station. */
+               AST_LIST_TRAVERSE(&ringing_station->station->trunks, trunk_ref, entry) {
+                       struct sla_station_ref *station_ref;
+                       int trunk_time_elapsed, trunk_time_left;
+
+                       AST_LIST_TRAVERSE(&sla.ringing_trunks, ringing_trunk, entry) {
+                               if (ringing_trunk->trunk == trunk_ref->trunk) {
+                                       break;
+                               }
+                       }
+                       if (!ringing_trunk) {
+                               continue;
+                       }
+
+                       /* If there is a trunk that is ringing without a timeout, then the
+                        * only timeout that could matter is a global station ring timeout. */
+                       if (!trunk_ref->ring_timeout) {
+                               break;
+                       }
+
+                       /* This trunk on this station is ringing and has a timeout.
+                        * However, make sure this trunk isn't still ringing from a
+                        * previous timeout.  If so, don't consider it. */
+                       AST_LIST_TRAVERSE(&ringing_trunk->timed_out_stations, station_ref, entry) {
+                               if (station_ref->station == ringing_station->station) {
+                                       break;
+                               }
+                       }
+                       if (station_ref) {
+                               continue;
+                       }
+
+                       trunk_time_elapsed = ast_tvdiff_ms(ast_tvnow(), ringing_trunk->ring_begin);
+                       trunk_time_left = (trunk_ref->ring_timeout * 1000) - trunk_time_elapsed;
+                       if (trunk_time_left > final_trunk_time_left) {
+                               final_trunk_time_left = trunk_time_left;
+                       }
+               }
+
+               /* No timeout was found for ringing trunks, and no timeout for the entire station */
+               if (final_trunk_time_left == INT_MIN && !ringing_station->station->ring_timeout) {
+                       continue;
+               }
+
+               /* Compute how much time is left for a global station timeout */
+               if (ringing_station->station->ring_timeout) {
+                       ring_timeout = ringing_station->station->ring_timeout;
+                       time_elapsed = ast_tvdiff_ms(ast_tvnow(), ringing_station->ring_begin);
+                       time_left = (ring_timeout * 1000) - time_elapsed;
+               }
+
+               /* If the time left based on the per-trunk timeouts is smaller than the
+                * global station ring timeout, use that. */
+               if (final_trunk_time_left > INT_MIN && final_trunk_time_left < time_left) {
+                       time_left = final_trunk_time_left;
+               }
+
+               /* If there is no time left, the station needs to stop ringing */
+               if (time_left <= 0) {
+                       AST_LIST_REMOVE_CURRENT(entry);
+                       sla_stop_ringing_station(ringing_station, SLA_STATION_HANGUP_TIMEOUT);
+                       res = 1;
+                       continue;
+               }
+
+               /* There is still some time left for this station to ring, so save that
+                * timeout if it is the first event scheduled to occur */
+               if (time_left < *timeout) {
+                       *timeout = time_left;
+               }
+       }
+       AST_LIST_TRAVERSE_SAFE_END;
+
+       return res;
+}
+
+/*! \brief Calculate the ring delay for a station
+ * \note Assumes sla.lock is locked
+ */
+static int sla_calc_station_delays(unsigned int *timeout)
+{
+       struct sla_station *station;
+       int res = 0;
+       struct ao2_iterator i;
+
+       i = ao2_iterator_init(sla_stations, 0);
+       for (; (station = ao2_iterator_next(&i)); ao2_ref(station, -1)) {
+               struct sla_ringing_trunk *ringing_trunk;
+               int time_left;
+
+               /* Ignore stations already ringing */
+               if (sla_check_ringing_station(station)) {
+                       continue;
+               }
+
+               /* Ignore stations already on a call */
+               if (sla_check_inuse_station(station)) {
+                       continue;
+               }
+
+               /* Ignore stations that don't have one of their trunks ringing */
+               if (!(ringing_trunk = sla_choose_ringing_trunk(station, NULL, 0))) {
+                       continue;
+               }
+
+               if ((time_left = sla_check_station_delay(station, ringing_trunk)) == INT_MAX) {
+                       continue;
+               }
+
+               /* If there is no time left, then the station needs to start ringing.
+                * Return non-zero so that an event will be queued up an event to
+                * make that happen. */
+               if (time_left <= 0) {
+                       res = 1;
+                       continue;
+               }
+
+               if (time_left < *timeout) {
+                       *timeout = time_left;
+               }
+       }
+       ao2_iterator_destroy(&i);
+
+       return res;
+}
+
+/*! \brief Calculate the time until the next known event
+ *  \note Called with sla.lock locked */
+static int sla_process_timers(struct timespec *ts)
+{
+       unsigned int timeout = UINT_MAX;
+       struct timeval wait;
+       unsigned int change_made = 0;
+
+       /* Check for ring timeouts on ringing trunks */
+       if (sla_calc_trunk_timeouts(&timeout)) {
+               change_made = 1;
+       }
+
+       /* Check for ring timeouts on ringing stations */
+       if (sla_calc_station_timeouts(&timeout)) {
+               change_made = 1;
+       }
+
+       /* Check for station ring delays */
+       if (sla_calc_station_delays(&timeout)) {
+               change_made = 1;
+       }
+
+       /* queue reprocessing of ringing trunks */
+       if (change_made) {
+               sla_queue_event_nolock(SLA_EVENT_RINGING_TRUNK);
+       }
+
+       /* No timeout */
+       if (timeout == UINT_MAX) {
+               return 0;
+       }
+
+       if (ts) {
+               wait = ast_tvadd(ast_tvnow(), ast_samp2tv(timeout, 1000));
+               ts->tv_sec = wait.tv_sec;
+               ts->tv_nsec = wait.tv_usec * 1000;
+       }
+
+       return 1;
+}
+
+static void sla_event_destroy(struct sla_event *event)
+{
+       if (event->trunk_ref) {
+               ao2_ref(event->trunk_ref, -1);
+               event->trunk_ref = NULL;
+       }
+
+       if (event->station) {
+               ao2_ref(event->station, -1);
+               event->station = NULL;
+       }
+
+       ast_free(event);
+}
+
+static void *sla_thread(void *data)
+{
+       struct sla_failed_station *failed_station;
+       struct sla_ringing_station *ringing_station;
+
+       ast_mutex_lock(&sla.lock);
+
+       while (!sla.stop) {
+               struct sla_event *event;
+               struct timespec ts = { 0, };
+               unsigned int have_timeout = 0;
+
+               if (AST_LIST_EMPTY(&sla.event_q)) {
+                       if ((have_timeout = sla_process_timers(&ts))) {
+                               ast_cond_timedwait(&sla.cond, &sla.lock, &ts);
+                       } else {
+                               ast_cond_wait(&sla.cond, &sla.lock);
+                       }
+                       if (sla.stop) {
+                               break;
+                       }
+               }
+
+               if (have_timeout) {
+                       sla_process_timers(NULL);
+               }
+
+               while ((event = AST_LIST_REMOVE_HEAD(&sla.event_q, entry))) {
+                       ast_mutex_unlock(&sla.lock);
+                       switch (event->type) {
+                       case SLA_EVENT_HOLD:
+                               sla_handle_hold_event(event);
+                               break;
+                       case SLA_EVENT_DIAL_STATE:
+                               sla_handle_dial_state_event();
+                               break;
+                       case SLA_EVENT_RINGING_TRUNK:
+                               sla_handle_ringing_trunk_event();
+                               break;
+                       }
+                       sla_event_destroy(event);
+                       ast_mutex_lock(&sla.lock);
+               }
+       }
+
+       ast_mutex_unlock(&sla.lock);
+
+       while ((ringing_station = AST_LIST_REMOVE_HEAD(&sla.ringing_stations, entry))) {
+               sla_ringing_station_destroy(ringing_station);
+       }
+
+       while ((failed_station = AST_LIST_REMOVE_HEAD(&sla.failed_stations, entry))) {
+               sla_failed_station_destroy(failed_station);
+       }
+
+       return NULL;
+}
+
+struct dial_trunk_args {
+       struct sla_trunk_ref *trunk_ref;
+       struct sla_station *station;
+       ast_mutex_t *cond_lock;
+       ast_cond_t *cond;
+};
+
+static void *dial_trunk(void *data)
+{
+       struct dial_trunk_args *args = data;
+       struct ast_dial *dial;
+       char *tech, *tech_data;
+       enum ast_dial_result dial_res;
+       char conf_name[MAX_CONFNUM];
+       struct ast_flags conf_flags = { 0 };
+       RAII_VAR(struct sla_trunk_ref *, trunk_ref, args->trunk_ref, ao2_cleanup);
+       RAII_VAR(struct sla_station *, station, args->station, ao2_cleanup);
+       int caller_is_saved;
+       struct ast_party_caller caller;
+       int last_state = 0;
+       int current_state = 0;
+
+       if (!(dial = ast_dial_create())) {
+               ast_mutex_lock(args->cond_lock);
+               ast_cond_signal(args->cond);
+               ast_mutex_unlock(args->cond_lock);
+               return NULL;
+       }
+
+       tech_data = ast_strdupa(trunk_ref->trunk->device);
+       tech = strsep(&tech_data, "/");
+       if (ast_dial_append(dial, tech, tech_data, NULL) == -1) {
+               ast_mutex_lock(args->cond_lock);
+               ast_cond_signal(args->cond);
+               ast_mutex_unlock(args->cond_lock);
+               ast_dial_destroy(dial);
+               return NULL;
+       }
+
+       /* Do we need to save of the caller ID data? */
+       caller_is_saved = 0;
+       if (!sla.attempt_callerid) {
+               caller_is_saved = 1;
+               caller = *ast_channel_caller(trunk_ref->chan);
+               ast_party_caller_init(ast_channel_caller(trunk_ref->chan));
+       }
+
+       dial_res = ast_dial_run(dial, trunk_ref->chan, 1);
+
+       /* Restore saved caller ID */
+       if (caller_is_saved) {
+               ast_party_caller_free(ast_channel_caller(trunk_ref->chan));
+               ast_channel_caller_set(trunk_ref->chan, &caller);
+       }
+
+       if (dial_res != AST_DIAL_RESULT_TRYING) {
+               ast_mutex_lock(args->cond_lock);
+               ast_cond_signal(args->cond);
+               ast_mutex_unlock(args->cond_lock);
+               ast_dial_destroy(dial);
+               return NULL;
+       }
+
+       /* Wait for dial to end, while servicing the channel */
+       while (ast_waitfor(trunk_ref->chan, 100)) {
+               unsigned int done = 0;
+               struct ast_frame *fr = ast_read(trunk_ref->chan);
+
+               if (!fr) {
+                       ast_debug(1, "Channel %s did not return a frame, must have hung up\n", ast_channel_name(trunk_ref->chan));
+                       done = 1;
+                       break;
+               }
+               ast_frfree(fr); /* Ignore while dialing */
+
+               switch ((dial_res = ast_dial_state(dial))) {
+               case AST_DIAL_RESULT_ANSWERED:
+                       trunk_ref->trunk->chan = ast_dial_answered(dial);
+               case AST_DIAL_RESULT_HANGUP:
+               case AST_DIAL_RESULT_INVALID:
+               case AST_DIAL_RESULT_FAILED:
+               case AST_DIAL_RESULT_TIMEOUT:
+               case AST_DIAL_RESULT_UNANSWERED:
+                       done = 1;
+                       break;
+               case AST_DIAL_RESULT_TRYING:
+                       current_state = AST_CONTROL_PROGRESS;
+                       break;
+               case AST_DIAL_RESULT_RINGING:
+               case AST_DIAL_RESULT_PROGRESS:
+               case AST_DIAL_RESULT_PROCEEDING:
+                       current_state = AST_CONTROL_RINGING;
+                       break;
+               }
+               if (done) {
+                       break;
+               }
+
+               /* check that SLA station that originated trunk call is still alive */
+               if (station && ast_device_state(station->device) == AST_DEVICE_NOT_INUSE) {
+                       ast_debug(3, "Originating station device %s no longer active\n", station->device);
+                       trunk_ref->trunk->chan = NULL;
+                       break;
+               }
+
+               /* If trunk line state changed, send indication back to originating SLA Station channel */
+               if (current_state != last_state) {
+                       ast_debug(3, "Indicating State Change %d to channel %s\n", current_state, ast_channel_name(trunk_ref->chan));
+                       ast_indicate(trunk_ref->chan, current_state);
+                       last_state = current_state;
+               }
+       }
+
+       if (!trunk_ref->trunk->chan) {
+               ast_mutex_lock(args->cond_lock);
+               ast_cond_signal(args->cond);
+               ast_mutex_unlock(args->cond_lock);
+               ast_dial_join(dial);
+               ast_dial_destroy(dial);
+               return NULL;
+       }
+
+       snprintf(conf_name, sizeof(conf_name), "SLA_%s", trunk_ref->trunk->name);
+       ast_set_flag(&conf_flags, CONFFLAG_QUIET | CONFFLAG_MARKEDEXIT | CONFFLAG_MARKEDUSER | CONFFLAG_PASS_DTMF | CONFFLAG_SLA_TRUNK);
+
+       ast_mutex_lock(args->cond_lock);
+       ast_cond_signal(args->cond);
+       ast_mutex_unlock(args->cond_lock);
+
+       ast_debug(2, "Trunk dial %s joining conference %s\n", trunk_ref->trunk->name, conf_name);
+       conf_run(trunk_ref->trunk->chan, conf_name, &conf_flags, NULL);
+
+       /* If the trunk is going away, it is definitely now IDLE. */
+       sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
+
+       trunk_ref->trunk->chan = NULL;
+       trunk_ref->trunk->on_hold = 0;
+
+       ast_dial_join(dial);
+       ast_dial_destroy(dial);
+
+       return NULL;
+}
+
+/*!
+ * \brief For a given station, choose the highest priority idle trunk
+ * \pre sla_station is locked
+ */
+static struct sla_trunk_ref *sla_choose_idle_trunk(const struct sla_station *station)
+{
+       struct sla_trunk_ref *trunk_ref = NULL;
+
+       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+               if (trunk_ref->state == SLA_TRUNK_STATE_IDLE) {
+                       ao2_ref(trunk_ref, 1);
+                       break;
+               }
+       }
+
+       return trunk_ref;
+}
+
+static int sla_station_exec(struct ast_channel *chan, const char *data)
+{
+       char *station_name, *trunk_name;
+       RAII_VAR(struct sla_station *, station, NULL, ao2_cleanup);
+       RAII_VAR(struct sla_trunk_ref *, trunk_ref, NULL, ao2_cleanup);
+       char conf_name[MAX_CONFNUM];
+       struct ast_flags conf_flags = { 0 };
+
+       if (ast_strlen_zero(data)) {
+               ast_log(LOG_WARNING, "Invalid Arguments to SLAStation!\n");
+               pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "FAILURE");
+               return 0;
+       }
+
+       trunk_name = ast_strdupa(data);
+       station_name = strsep(&trunk_name, "_");
+
+       if (ast_strlen_zero(station_name)) {
+               ast_log(LOG_WARNING, "Invalid Arguments to SLAStation!\n");
+               pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "FAILURE");
+               return 0;
+       }
+
+       station = sla_find_station(station_name);
+
+       if (!station) {
+               ast_log(LOG_WARNING, "Station '%s' not found!\n", station_name);
+               pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "FAILURE");
+               return 0;
+       }
+
+       ao2_lock(station);
+       if (!ast_strlen_zero(trunk_name)) {
+               trunk_ref = sla_find_trunk_ref_byname(station, trunk_name);
+       } else {
+               trunk_ref = sla_choose_idle_trunk(station);
+       }
+       ao2_unlock(station);
+
+       if (!trunk_ref) {
+               if (ast_strlen_zero(trunk_name)) {
+                       ast_log(LOG_NOTICE, "No trunks available for call.\n");
+               } else {
+                       ast_log(LOG_NOTICE, "Can't join existing call on trunk '%s' due to access controls.\n", trunk_name);
+               }
+               pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "CONGESTION");
+               return 0;
+       }
+
+       if (trunk_ref->state == SLA_TRUNK_STATE_ONHOLD_BYME) {
+               if (ast_atomic_dec_and_test((int *) &trunk_ref->trunk->hold_stations) == 1) {
+                       sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_UP, ALL_TRUNK_REFS, NULL);
+               } else {
+                       trunk_ref->state = SLA_TRUNK_STATE_UP;
+                       ast_devstate_changed(AST_DEVICE_INUSE, AST_DEVSTATE_CACHABLE, "SLA:%s_%s", station->name, trunk_ref->trunk->name);
+               }
+       } else if (trunk_ref->state == SLA_TRUNK_STATE_RINGING) {
+               struct sla_ringing_trunk *ringing_trunk;
+
+               ast_mutex_lock(&sla.lock);
+               AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_trunks, ringing_trunk, entry) {
+                       if (ringing_trunk->trunk == trunk_ref->trunk) {
+                               AST_LIST_REMOVE_CURRENT(entry);
+                               break;
+                       }
+               }
+               AST_LIST_TRAVERSE_SAFE_END
+               ast_mutex_unlock(&sla.lock);
+
+               if (ringing_trunk) {
+                       answer_trunk_chan(ringing_trunk->trunk->chan);
+                       sla_change_trunk_state(ringing_trunk->trunk, SLA_TRUNK_STATE_UP, ALL_TRUNK_REFS, NULL);
+
+                       sla_ringing_trunk_destroy(ringing_trunk);
+
+                       /* Queue up reprocessing ringing trunks, and then ringing stations again */
+                       sla_queue_event(SLA_EVENT_RINGING_TRUNK);
+                       sla_queue_event(SLA_EVENT_DIAL_STATE);
+               }
+       }
+
+       trunk_ref->chan = chan;
+
+       if (!trunk_ref->trunk->chan) {
+               ast_mutex_t cond_lock;
+               ast_cond_t cond;
+               pthread_t dont_care;
+               struct dial_trunk_args args = {
+                       .trunk_ref = trunk_ref,
+                       .station = station,
+                       .cond_lock = &cond_lock,
+                       .cond = &cond,
+               };
+               ao2_ref(trunk_ref, 1);
+               ao2_ref(station, 1);
+               sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_UP, ALL_TRUNK_REFS, NULL);
+               /* Create a thread to dial the trunk and dump it into the conference.
+                * However, we want to wait until the trunk has been dialed and the
+                * conference is created before continuing on here.
+                * Don't autoservice the channel or we'll have multiple threads
+                * handling it. dial_trunk services the channel.
+                */
+               ast_mutex_init(&cond_lock);
+               ast_cond_init(&cond, NULL);
+               ast_mutex_lock(&cond_lock);
+               ast_pthread_create_detached_background(&dont_care, NULL, dial_trunk, &args);
+               ast_cond_wait(&cond, &cond_lock);
+               ast_mutex_unlock(&cond_lock);
+               ast_mutex_destroy(&cond_lock);
+               ast_cond_destroy(&cond);
+
+               if (!trunk_ref->trunk->chan) {
+                       ast_debug(1, "Trunk didn't get created. chan: %lx\n", (unsigned long) trunk_ref->trunk->chan);
+                       pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "CONGESTION");
+                       sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
+                       trunk_ref->chan = NULL;
+                       return 0;
+               }
+       }
+
+       if (ast_atomic_fetchadd_int((int *) &trunk_ref->trunk->active_stations, 1) == 0 &&
+               trunk_ref->trunk->on_hold) {
+               trunk_ref->trunk->on_hold = 0;
+               ast_indicate(trunk_ref->trunk->chan, AST_CONTROL_UNHOLD);
+               sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_UP, ALL_TRUNK_REFS, NULL);
+       }
+
+       snprintf(conf_name, sizeof(conf_name), "SLA_%s", trunk_ref->trunk->name);
+       ast_set_flag(&conf_flags, CONFFLAG_QUIET | CONFFLAG_MARKEDEXIT | CONFFLAG_PASS_DTMF | CONFFLAG_SLA_STATION);
+       ast_answer(chan);
+
+       ast_debug(2, "Station %s joining conference %s\n", station->name, conf_name);
+       conf_run(chan, conf_name, &conf_flags, NULL);
+
+       trunk_ref->chan = NULL;
+       if (ast_atomic_dec_and_test((int *) &trunk_ref->trunk->active_stations) &&
+               trunk_ref->state != SLA_TRUNK_STATE_ONHOLD_BYME) {
+               conf_kick_all(chan, conf_name);
+               trunk_ref->trunk->hold_stations = 0;
+               sla_change_trunk_state(trunk_ref->trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
+       }
+
+       pbx_builtin_setvar_helper(chan, "SLASTATION_STATUS", "SUCCESS");
+
+       return 0;
+}
+
+static void sla_trunk_ref_destructor(void *obj)
+{
+       struct sla_trunk_ref *trunk_ref = obj;
+
+       if (trunk_ref->trunk) {
+               ao2_ref(trunk_ref->trunk, -1);
+               trunk_ref->trunk = NULL;
+       }
+}
+
+static struct sla_trunk_ref *create_trunk_ref(struct sla_trunk *trunk)
+{
+       struct sla_trunk_ref *trunk_ref;
+
+       if (!(trunk_ref = ao2_alloc(sizeof(*trunk_ref), sla_trunk_ref_destructor))) {
+               return NULL;
+       }
+
+       ao2_ref(trunk, 1);
+       trunk_ref->trunk = trunk;
+
+       return trunk_ref;
+}
+
+static struct sla_ringing_trunk *queue_ringing_trunk(struct sla_trunk *trunk)
+{
+       struct sla_ringing_trunk *ringing_trunk;
+
+       if (!(ringing_trunk = ast_calloc(1, sizeof(*ringing_trunk)))) {
+               return NULL;
+       }
+
+       ao2_ref(trunk, 1);
+       ringing_trunk->trunk = trunk;
+       ringing_trunk->ring_begin = ast_tvnow();
+
+       sla_change_trunk_state(trunk, SLA_TRUNK_STATE_RINGING, ALL_TRUNK_REFS, NULL);
+
+       ast_mutex_lock(&sla.lock);
+       AST_LIST_INSERT_HEAD(&sla.ringing_trunks, ringing_trunk, entry);
+       ast_mutex_unlock(&sla.lock);
+
+       sla_queue_event(SLA_EVENT_RINGING_TRUNK);
+
+       return ringing_trunk;
+}
+
+static void sla_ringing_trunk_destroy(struct sla_ringing_trunk *ringing_trunk)
+{
+       if (ringing_trunk->trunk) {
+               ao2_ref(ringing_trunk->trunk, -1);
+               ringing_trunk->trunk = NULL;
+       }
+
+       ast_free(ringing_trunk);
+}
+
+static int sla_trunk_exec(struct ast_channel *chan, const char *data)
+{
+       char conf_name[MAX_CONFNUM];
+       struct ast_flags conf_flags = { 0 };
+       RAII_VAR(struct sla_trunk *, trunk, NULL, ao2_cleanup);
+       struct sla_ringing_trunk *ringing_trunk;
+       AST_DECLARE_APP_ARGS(args,
+               AST_APP_ARG(trunk_name);
+               AST_APP_ARG(options);
+       );
+       char *opts[SLA_TRUNK_OPT_ARG_ARRAY_SIZE] = { NULL, };
+       struct ast_flags opt_flags = { 0 };
+       char *parse;
+
+       if (ast_strlen_zero(data)) {
+               ast_log(LOG_ERROR, "The SLATrunk application requires an argument, the trunk name\n");
+               return -1;
+       }
+
+       parse = ast_strdupa(data);
+       AST_STANDARD_APP_ARGS(args, parse);
+       if (args.argc == 2) {
+               if (ast_app_parse_options(sla_trunk_opts, &opt_flags, opts, args.options)) {
+                       ast_log(LOG_ERROR, "Error parsing options for SLATrunk\n");
+                       return -1;
+               }
+       }
+
+       trunk = sla_find_trunk(args.trunk_name);
+
+       if (!trunk) {
+               ast_log(LOG_ERROR, "SLA Trunk '%s' not found!\n", args.trunk_name);
+               pbx_builtin_setvar_helper(chan, "SLATRUNK_STATUS", "FAILURE");
+               return 0;
+       }
+
+       if (trunk->chan) {
+               ast_log(LOG_ERROR, "Call came in on %s, but the trunk is already in use!\n", args.trunk_name);
+               pbx_builtin_setvar_helper(chan, "SLATRUNK_STATUS", "FAILURE");
+               return 0;
+       }
+
+       trunk->chan = chan;
+
+       if (!(ringing_trunk = queue_ringing_trunk(trunk))) {
+               pbx_builtin_setvar_helper(chan, "SLATRUNK_STATUS", "FAILURE");
+               return 0;
+       }
+
+       snprintf(conf_name, sizeof(conf_name), "SLA_%s", args.trunk_name);
+       ast_set_flag(&conf_flags, CONFFLAG_QUIET | CONFFLAG_MARKEDEXIT | CONFFLAG_MARKEDUSER | CONFFLAG_PASS_DTMF);
+
+       if (ast_test_flag(&opt_flags, SLA_TRUNK_OPT_MOH)) {
+               ast_indicate(chan, -1);
+               ast_set_flag(&conf_flags, CONFFLAG_MOH);
+       } else {
+               ast_indicate(chan, AST_CONTROL_RINGING);
+       }
+
+       ast_debug(2, "Trunk %s joining conference %s\n", args.trunk_name, conf_name);
+       conf_run(chan, conf_name, &conf_flags, opts);
+       trunk->chan = NULL;
+       trunk->on_hold = 0;
+
+       sla_change_trunk_state(trunk, SLA_TRUNK_STATE_IDLE, ALL_TRUNK_REFS, NULL);
+
+       if (!pbx_builtin_getvar_helper(chan, "SLATRUNK_STATUS")) {
+               pbx_builtin_setvar_helper(chan, "SLATRUNK_STATUS", "SUCCESS");
+       }
+
+       /* Remove the entry from the list of ringing trunks if it is still there. */
+       ast_mutex_lock(&sla.lock);
+       AST_LIST_TRAVERSE_SAFE_BEGIN(&sla.ringing_trunks, ringing_trunk, entry) {
+               if (ringing_trunk->trunk == trunk) {
+                       AST_LIST_REMOVE_CURRENT(entry);
+                       break;
+               }
+       }
+       AST_LIST_TRAVERSE_SAFE_END;
+       ast_mutex_unlock(&sla.lock);
+       if (ringing_trunk) {
+               sla_ringing_trunk_destroy(ringing_trunk);
+               pbx_builtin_setvar_helper(chan, "SLATRUNK_STATUS", "UNANSWERED");
+               /* Queue reprocessing of ringing trunks to make stations stop ringing
+                * that shouldn't be ringing after this trunk stopped. */
+               sla_queue_event(SLA_EVENT_RINGING_TRUNK);
+       }
+
+       return 0;
+}
+
+static enum ast_device_state sla_state(const char *data)
+{
+       char *buf, *station_name, *trunk_name;
+       RAII_VAR(struct sla_station *, station, NULL, ao2_cleanup);
+       struct sla_trunk_ref *trunk_ref;
+       enum ast_device_state res = AST_DEVICE_INVALID;
+
+       trunk_name = buf = ast_strdupa(data);
+       station_name = strsep(&trunk_name, "_");
+
+       station = sla_find_station(station_name);
+       if (station) {
+               ao2_lock(station);
+               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+                       if (!strcasecmp(trunk_name, trunk_ref->trunk->name)) {
+                               res = sla_state_to_devstate(trunk_ref->state);
+                               break;
+                       }
+               }
+               ao2_unlock(station);
+       }
+
+       if (res == AST_DEVICE_INVALID) {
+               ast_log(LOG_ERROR, "Could not determine state for trunk %s on station %s!\n", trunk_name, station_name);
+       }
+
+       return res;
+}
+
+static int sla_trunk_release_refs(void *obj, void *arg, int flags)
+{
+       struct sla_trunk *trunk = obj;
+       struct sla_station_ref *station_ref;
+
+       while ((station_ref = AST_LIST_REMOVE_HEAD(&trunk->stations, entry))) {
+               ao2_ref(station_ref, -1);
+       }
+
+       return 0;
+}
+
+static int sla_station_release_refs(void *obj, void *arg, int flags)
+{
+       struct sla_station *station = obj;
+       struct sla_trunk_ref *trunk_ref;
+
+       while ((trunk_ref = AST_LIST_REMOVE_HEAD(&station->trunks, entry))) {
+               ao2_ref(trunk_ref, -1);
+       }
+
+       return 0;
+}
+
+static void sla_station_destructor(void *obj)
+{
+       struct sla_station *station = obj;
+
+       ast_debug(1, "sla_station destructor for '%s'\n", station->name);
+
+       if (!ast_strlen_zero(station->autocontext)) {
+               struct sla_trunk_ref *trunk_ref;
+
+               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+                       char exten[AST_MAX_EXTENSION];
+                       char hint[AST_MAX_EXTENSION + 5];
+                       snprintf(exten, sizeof(exten), "%s_%s", station->name, trunk_ref->trunk->name);
+                       snprintf(hint, sizeof(hint), "SLA:%s", exten);
+                       ast_context_remove_extension(station->autocontext, exten, 1, sla_registrar);
+                       ast_context_remove_extension(station->autocontext, hint, PRIORITY_HINT, sla_registrar);
+               }
+       }
+
+       sla_station_release_refs(station, NULL, 0);
+
+       ast_string_field_free_memory(station);
+}
+
+static int sla_trunk_cmp(void *obj, void *arg, int flags)
+{
+       struct sla_trunk *trunk = obj, *trunk2 = arg;
+
+       return !strcasecmp(trunk->name, trunk2->name) ? CMP_MATCH | CMP_STOP : 0;
+}
+
+static int sla_station_cmp(void *obj, void *arg, int flags)
+{
+       struct sla_station *station = obj, *station2 = arg;
+
+       return !strcasecmp(station->name, station2->name) ? CMP_MATCH | CMP_STOP : 0;
+}
+
+static void sla_destroy(void)
+{
+       if (sla.thread != AST_PTHREADT_NULL) {
+               ast_mutex_lock(&sla.lock);
+               sla.stop = 1;
+               ast_cond_signal(&sla.cond);
+               ast_mutex_unlock(&sla.lock);
+               pthread_join(sla.thread, NULL);
+       }
+
+       /* Drop any created contexts from the dialplan */
+       ast_context_destroy(NULL, sla_registrar);
+
+       ast_mutex_destroy(&sla.lock);
+       ast_cond_destroy(&sla.cond);
+
+       ao2_callback(sla_trunks, 0, sla_trunk_release_refs, NULL);
+       ao2_callback(sla_stations, 0, sla_station_release_refs, NULL);
+
+       ao2_ref(sla_trunks, -1);
+       sla_trunks = NULL;
+
+       ao2_ref(sla_stations, -1);
+       sla_stations = NULL;
+}
+
+static int sla_check_device(const char *device)
+{
+       char *tech, *tech_data;
+
+       tech_data = ast_strdupa(device);
+       tech = strsep(&tech_data, "/");
+
+       if (ast_strlen_zero(tech) || ast_strlen_zero(tech_data)) {
+               return -1;
+       }
+
+       return 0;
+}
+
+static void sla_trunk_destructor(void *obj)
+{
+       struct sla_trunk *trunk = obj;
+
+       ast_debug(1, "sla_trunk destructor for '%s'\n", trunk->name);
+
+       if (!ast_strlen_zero(trunk->autocontext)) {
+               ast_context_remove_extension(trunk->autocontext, "s", 1, sla_registrar);
+       }
+
+       sla_trunk_release_refs(trunk, NULL, 0);
+
+       ast_string_field_free_memory(trunk);
+}
+
+static int sla_build_trunk(struct ast_config *cfg, const char *cat)
+{
+       RAII_VAR(struct sla_trunk *, trunk, NULL, ao2_cleanup);
+       struct ast_variable *var;
+       const char *dev;
+       int existing_trunk = 0;
+
+       if (!(dev = ast_variable_retrieve(cfg, cat, "device"))) {
+               ast_log(LOG_ERROR, "SLA Trunk '%s' defined with no device!\n", cat);
+               return -1;
+       }
+
+       if (sla_check_device(dev)) {
+               ast_log(LOG_ERROR, "SLA Trunk '%s' defined with invalid device '%s'!\n", cat, dev);
+               return -1;
+       }
+
+       if ((trunk = sla_find_trunk(cat))) {
+               trunk->mark = 0;
+               existing_trunk = 1;
+       } else if ((trunk = ao2_alloc(sizeof(*trunk), sla_trunk_destructor))) {
+               if (ast_string_field_init(trunk, 32)) {
+                       return -1;
+               }
+               ast_string_field_set(trunk, name, cat);
+       } else {
+               return -1;
+       }
+
+       ao2_lock(trunk);
+
+       ast_string_field_set(trunk, device, dev);
+
+       for (var = ast_variable_browse(cfg, cat); var; var = var->next) {
+               if (!strcasecmp(var->name, "autocontext")) {
+                       ast_string_field_set(trunk, autocontext, var->value);
+               } else if (!strcasecmp(var->name, "ringtimeout")) {
+                       if (sscanf(var->value, "%30u", &trunk->ring_timeout) != 1) {
+                               ast_log(LOG_WARNING, "Invalid ringtimeout '%s' specified for trunk '%s'\n", var->value, trunk->name);
+                               trunk->ring_timeout = 0;
+                       }
+               } else if (!strcasecmp(var->name, "barge")) {
+                       trunk->barge_disabled = ast_false(var->value);
+               } else if (!strcasecmp(var->name, "hold")) {
+                       if (!strcasecmp(var->value, "private")) {
+                               trunk->hold_access = SLA_HOLD_PRIVATE;
+                       } else if (!strcasecmp(var->value, "open")) {
+                               trunk->hold_access = SLA_HOLD_OPEN;
+                       } else {
+                               ast_log(LOG_WARNING, "Invalid value '%s' for hold on trunk %s\n", var->value, trunk->name);
+                       }
+               } else if (strcasecmp(var->name, "type") && strcasecmp(var->name, "device")) {
+                       ast_log(LOG_ERROR, "Invalid option '%s' specified at line %d of %s!\n", var->name, var->lineno, SLA_CONFIG_FILE);
+               }
+       }
+
+       ao2_unlock(trunk);
+
+       if (!ast_strlen_zero(trunk->autocontext)) {
+               if (!ast_context_find_or_create(NULL, NULL, trunk->autocontext, sla_registrar)) {
+                       ast_log(LOG_ERROR, "Failed to automatically find or create context '%s' for SLA!\n", trunk->autocontext);
+                       return -1;
+               }
+
+               if (ast_add_extension(trunk->autocontext, 0 /* don't replace */, "s", 1,
+                       NULL, NULL, slatrunk_app, ast_strdup(trunk->name), ast_free_ptr, sla_registrar)) {
+                       ast_log(LOG_ERROR, "Failed to automatically create extension for trunk '%s'!\n", trunk->name);
+                       return -1;
+               }
+       }
+
+       if (!existing_trunk) {
+               ao2_link(sla_trunks, trunk);
+       }
+
+       return 0;
+}
+
+/*!
+ * \internal
+ * \pre station is not locked
+ */
+static void sla_add_trunk_to_station(struct sla_station *station, struct ast_variable *var)
+{
+       RAII_VAR(struct sla_trunk *, trunk, NULL, ao2_cleanup);
+       struct sla_trunk_ref *trunk_ref = NULL;
+       struct sla_station_ref *station_ref;
+       char *trunk_name, *options, *cur;
+       int existing_trunk_ref = 0;
+       int existing_station_ref = 0;
+
+       options = ast_strdupa(var->value);
+       trunk_name = strsep(&options, ",");
+
+       trunk = sla_find_trunk(trunk_name);
+       if (!trunk) {
+               ast_log(LOG_ERROR, "Trunk '%s' not found!\n", var->value);
+               return;
+       }
+
+       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+               if (trunk_ref->trunk == trunk) {
+                       trunk_ref->mark = 0;
+                       existing_trunk_ref = 1;
+                       break;
+               }
+       }
+
+       if (!trunk_ref && !(trunk_ref = create_trunk_ref(trunk))) {
+               return;
+       }
+
+       trunk_ref->state = SLA_TRUNK_STATE_IDLE;
+
+       while ((cur = strsep(&options, ","))) {
+               char *name, *value = cur;
+               name = strsep(&value, "=");
+               if (!strcasecmp(name, "ringtimeout")) {
+                       if (sscanf(value, "%30u", &trunk_ref->ring_timeout) != 1) {
+                               ast_log(LOG_WARNING, "Invalid ringtimeout value '%s' for trunk '%s' on station '%s'\n", value, trunk->name, station->name);
+                               trunk_ref->ring_timeout = 0;
+                       }
+               } else if (!strcasecmp(name, "ringdelay")) {
+                       if (sscanf(value, "%30u", &trunk_ref->ring_delay) != 1) {
+                               ast_log(LOG_WARNING, "Invalid ringdelay value '%s' for trunk '%s' on station '%s'\n", value, trunk->name, station->name);
+                               trunk_ref->ring_delay = 0;
+                       }
+               } else {
+                       ast_log(LOG_WARNING, "Invalid option '%s' for trunk '%s' on station '%s'\n", name, trunk->name, station->name);
+               }
+       }
+
+       AST_LIST_TRAVERSE(&trunk->stations, station_ref, entry) {
+               if (station_ref->station == station) {
+                       station_ref->mark = 0;
+                       existing_station_ref = 1;
+                       break;
+               }
+       }
+
+       if (!station_ref && !(station_ref = sla_create_station_ref(station))) {
+               if (!existing_trunk_ref) {
+                       ao2_ref(trunk_ref, -1);
+               } else {
+                       trunk_ref->mark = 1;
+               }
+               return;
+       }
+
+       if (!existing_station_ref) {
+               ao2_lock(trunk);
+               AST_LIST_INSERT_TAIL(&trunk->stations, station_ref, entry);
+               ast_atomic_fetchadd_int((int *) &trunk->num_stations, 1);
+               ao2_unlock(trunk);
+       }
+
+       if (!existing_trunk_ref) {
+               ao2_lock(station);
+               AST_LIST_INSERT_TAIL(&station->trunks, trunk_ref, entry);
+               ao2_unlock(station);
+       }
+}
+
+static int sla_build_station(struct ast_config *cfg, const char *cat)
+{
+       RAII_VAR(struct sla_station *, station, NULL, ao2_cleanup);
+       struct ast_variable *var;
+       const char *dev;
+       int existing_station = 0;
+
+       if (!(dev = ast_variable_retrieve(cfg, cat, "device"))) {
+               ast_log(LOG_ERROR, "SLA Station '%s' defined with no device!\n", cat);
+               return -1;
+       }
+
+       if ((station = sla_find_station(cat))) {
+               station->mark = 0;
+               existing_station = 1;
+       } else if ((station = ao2_alloc(sizeof(*station), sla_station_destructor))) {
+               if (ast_string_field_init(station, 32)) {
+                       return -1;
+               }
+               ast_string_field_set(station, name, cat);
+       } else {
+               return -1;
+       }
+
+       ao2_lock(station);
+
+       ast_string_field_set(station, device, dev);
+
+       for (var = ast_variable_browse(cfg, cat); var; var = var->next) {
+               if (!strcasecmp(var->name, "trunk")) {
+                       ao2_unlock(station);
+                       sla_add_trunk_to_station(station, var);
+                       ao2_lock(station);
+               } else if (!strcasecmp(var->name, "autocontext")) {
+                       ast_string_field_set(station, autocontext, var->value);
+               } else if (!strcasecmp(var->name, "ringtimeout")) {
+                       if (sscanf(var->value, "%30u", &station->ring_timeout) != 1) {
+                               ast_log(LOG_WARNING, "Invalid ringtimeout '%s' specified for station '%s'\n", var->value, station->name);
+                               station->ring_timeout = 0;
+                       }
+               } else if (!strcasecmp(var->name, "ringdelay")) {
+                       if (sscanf(var->value, "%30u", &station->ring_delay) != 1) {
+                               ast_log(LOG_WARNING, "Invalid ringdelay '%s' specified for station '%s'\n", var->value, station->name);
+                               station->ring_delay = 0;
+                       }
+               } else if (!strcasecmp(var->name, "hold")) {
+                       if (!strcasecmp(var->value, "private")) {
+                               station->hold_access = SLA_HOLD_PRIVATE;
+                       } else if (!strcasecmp(var->value, "open")) {
+                               station->hold_access = SLA_HOLD_OPEN;
+                       } else {
+                               ast_log(LOG_WARNING, "Invalid value '%s' for hold on station %s\n", var->value, station->name);
+                       }
+               } else if (strcasecmp(var->name, "type") && strcasecmp(var->name, "device")) {
+                       ast_log(LOG_ERROR, "Invalid option '%s' specified at line %d of %s!\n", var->name, var->lineno, SLA_CONFIG_FILE);
+               }
+       }
+
+       ao2_unlock(station);
+
+       if (!ast_strlen_zero(station->autocontext)) {
+               struct sla_trunk_ref *trunk_ref;
+
+               if (!ast_context_find_or_create(NULL, NULL, station->autocontext, sla_registrar)) {
+                       ast_log(LOG_ERROR, "Failed to automatically find or create context '%s' for SLA!\n", station->autocontext);
+                       return -1;
+               }
+               /* The extension for when the handset goes off-hook.
+                * exten => station1,1,SLAStation(station1) */
+               if (ast_add_extension(station->autocontext, 0 /* don't replace */, station->name, 1,
+                       NULL, NULL, slastation_app, ast_strdup(station->name), ast_free_ptr, sla_registrar)) {
+                       ast_log(LOG_ERROR, "Failed to automatically create extension for trunk '%s'!\n", station->name);
+                       return -1;
+               }
+               AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+                       char exten[AST_MAX_EXTENSION];
+                       char hint[AST_MAX_EXTENSION + 5];
+                       snprintf(exten, sizeof(exten), "%s_%s", station->name, trunk_ref->trunk->name);
+                       snprintf(hint, sizeof(hint), "SLA:%s", exten);
+                       /* Extension for this line button
+                        * exten => station1_line1,1,SLAStation(station1_line1) */
+                       if (ast_add_extension(station->autocontext, 0 /* don't replace */, exten, 1,
+                               NULL, NULL, slastation_app, ast_strdup(exten), ast_free_ptr, sla_registrar)) {
+                               ast_log(LOG_ERROR, "Failed to automatically create extension for trunk '%s'!\n", station->name);
+                               return -1;
+                       }
+                       /* Hint for this line button
+                        * exten => station1_line1,hint,SLA:station1_line1 */
+                       if (ast_add_extension(station->autocontext, 0 /* don't replace */, exten, PRIORITY_HINT,
+                               NULL, NULL, hint, NULL, NULL, sla_registrar)) {
+                               ast_log(LOG_ERROR, "Failed to automatically create hint for trunk '%s'!\n", station->name);
+                               return -1;
+                       }
+               }
+       }
+
+       if (!existing_station) {
+               ao2_link(sla_stations, station);
+       }
+
+       return 0;
+}
+
+static int sla_trunk_mark(void *obj, void *arg, int flags)
+{
+       struct sla_trunk *trunk = obj;
+       struct sla_station_ref *station_ref;
+
+       ao2_lock(trunk);
+
+       trunk->mark = 1;
+
+       AST_LIST_TRAVERSE(&trunk->stations, station_ref, entry) {
+               station_ref->mark = 1;
+       }
+
+       ao2_unlock(trunk);
+
+       return 0;
+}
+
+static int sla_station_mark(void *obj, void *arg, int flags)
+{
+       struct sla_station *station = obj;
+       struct sla_trunk_ref *trunk_ref;
+
+       ao2_lock(station);
+
+       station->mark = 1;
+
+       AST_LIST_TRAVERSE(&station->trunks, trunk_ref, entry) {
+               trunk_ref->mark = 1;
+       }
+
+       ao2_unlock(station);
+
+       return 0;
+}
+
+static int sla_trunk_is_marked(void *obj, void *arg, int flags)
+{
+       struct sla_trunk *trunk = obj;
+
+       ao2_lock(trunk);
+
+       if (trunk->mark) {
+               /* Only remove all of the station references if the trunk itself is going away */
+               sla_trunk_release_refs(trunk, NULL, 0);
+       } else {
+               struct sla_station_ref *station_ref;
+
+               /* Otherwise only remove references to stations no longer in the config */
+               AST_LIST_TRAVERSE_SAFE_BEGIN(&trunk->stations, station_ref, entry) {
+                       if (!station_ref->mark) {
+                               continue;
+                       }
+                       AST_LIST_REMOVE_CURRENT(entry);
+                       ao2_ref(station_ref, -1);
+               }
+               AST_LIST_TRAVERSE_SAFE_END
+       }
+
+       ao2_unlock(trunk);
+
+       return trunk->mark ? CMP_MATCH : 0;
+}
+
+static int sla_station_is_marked(void *obj, void *arg, int flags)
+{
+       struct sla_station *station = obj;
+
+       ao2_lock(station);
+
+       if (station->mark) {
+               /* Only remove all of the trunk references if the station itself is going away */
+               sla_station_release_refs(station, NULL, 0);
+       } else {
+               struct sla_trunk_ref *trunk_ref;
+
+               /* Otherwise only remove references to trunks no longer in the config */
+               AST_LIST_TRAVERSE_SAFE_BEGIN(&station->trunks, trunk_ref, entry) {
+                       if (!trunk_ref->mark) {
+                               continue;
+                       }
+                       AST_LIST_REMOVE_CURRENT(entry);
+                       ao2_ref(trunk_ref, -1);
+               }
+               AST_LIST_TRAVERSE_SAFE_END
+       }
+
+       ao2_unlock(station);
+
+       return station->mark ? CMP_MATCH : 0;
+}
+
+static int sla_in_use(void)
+{
+       return ao2_container_count(sla_trunks) || ao2_container_count(sla_stations);
+}
+
+static int sla_load_config(int reload)
+{
+       struct ast_config *cfg;
+       struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
+       const char *cat = NULL;
+       int res = 0;
+       const char *val;
+
+       if (!reload) {
+               ast_mutex_init(&sla.lock);
+               ast_cond_init(&sla.cond, NULL);
+               sla_trunks = ao2_container_alloc_list(AO2_ALLOC_OPT_LOCK_MUTEX, 0, NULL, sla_trunk_cmp);
+               sla_stations = ao2_container_alloc_list(AO2_ALLOC_OPT_LOCK_MUTEX, 0, NULL, sla_station_cmp);
+       }
+
+       if (!(cfg = ast_config_load(SLA_CONFIG_FILE, config_flags))) {
+               return 0; /* Treat no config as normal */
+       } else if (cfg == CONFIG_STATUS_FILEUNCHANGED) {
+               return 0;
+       } else if (cfg == CONFIG_STATUS_FILEINVALID) {
+               ast_log(LOG_ERROR, "Config file " SLA_CONFIG_FILE " is in an invalid format.  Aborting.\n");
+               return 0;
+       }
+
+       if (reload) {
+               ao2_callback(sla_trunks, 0, sla_trunk_mark, NULL);
+               ao2_callback(sla_stations, 0, sla_station_mark, NULL);
+       }
+
+       if ((val = ast_variable_retrieve(cfg, "general", "attemptcallerid"))) {
+               sla.attempt_callerid = ast_true(val);
+       }
+
+       while ((cat = ast_category_browse(cfg, cat)) && !res) {
+               const char *type;
+               if (!strcasecmp(cat, "general")) {
+                       continue;
+               }
+               if (!(type = ast_variable_retrieve(cfg, cat, "type"))) {
+                       ast_log(LOG_WARNING, "Invalid entry in %s defined with no type!\n", SLA_CONFIG_FILE);
+                       continue;
+               }
+               if (!strcasecmp(type, "trunk")) {
+                       res = sla_build_trunk(cfg, cat);
+               } else if (!strcasecmp(type, "station")) {
+                       res = sla_build_station(cfg, cat);
+               } else {
+                       ast_log(LOG_WARNING, "Entry in %s defined with invalid type '%s'!\n", SLA_CONFIG_FILE, type);
+               }
+       }
+
+       ast_config_destroy(cfg);
+
+       if (reload) {
+               ao2_callback(sla_trunks, OBJ_NODATA | OBJ_UNLINK | OBJ_MULTIPLE, sla_trunk_is_marked, NULL);
+               ao2_callback(sla_stations, OBJ_NODATA | OBJ_UNLINK | OBJ_MULTIPLE, sla_station_is_marked, NULL);
+       }
+
+       /* Start SLA event processing thread once SLA has been configured. */
+       if (sla.thread == AST_PTHREADT_NULL && sla_in_use()) {
+               ast_pthread_create(&sla.thread, NULL, sla_thread, NULL);
+       }
+
+       return res;
+}
+
+static int load_config(int reload)
+{
+       return sla_load_config(reload);
+}
+
+static int unload_module(void)
+{
+       int res = 0;
+
+       ast_cli_unregister_multiple(cli_sla, ARRAY_LEN(cli_sla));
+       res |= ast_unregister_application(slastation_app);
+       res |= ast_unregister_application(slatrunk_app);
+
+       ast_devstate_prov_del("SLA");
+
+       sla_destroy();
+
+       return res;
+}
+
+/*!
+ * \brief Load the module
+ *
+ * Module loading including tests for configuration or dependencies.
+ * This function can return AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_DECLINE,
+ * or AST_MODULE_LOAD_SUCCESS. If a dependency or environment variable fails
+ * tests return AST_MODULE_LOAD_FAILURE. If the module can not load the
+ * configuration file or other non-critical problem return
+ * AST_MODULE_LOAD_DECLINE. On success return AST_MODULE_LOAD_SUCCESS.
+ */
+static int load_module(void)
+{
+       int res = 0;
+
+       res |= load_config(0);
+
+       ast_cli_register_multiple(cli_sla, ARRAY_LEN(cli_sla));
+       res |= ast_register_application_xml(slastation_app, sla_station_exec);
+       res |= ast_register_application_xml(slatrunk_app, sla_trunk_exec);
+
+       res |= ast_devstate_prov_add("SLA", sla_state);
+
+       return res;
+}
+
+static int reload(void)
+{
+       return load_config(1);
+}
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Shared Line Appearances",
+       .support_level = AST_MODULE_SUPPORT_EXTENDED,
+       .load = load_module,
+       .unload = unload_module,
+       .reload = reload,
+       .load_pri = AST_MODPRI_DEVSTATE_PROVIDER,
+);