res_corosync.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2007, Digium, Inc.
 * Copyright (C) 2012, Russell Bryant
 *
 * Russell Bryant <[email protected]>
 *
 * 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
 * \author Russell Bryant <[email protected]>
 *
 * This module is based on and replaces the previous res_ais module.
 */

/*** MODULEINFO
   <depend>corosync</depend>
   <defaultenabled>no</defaultenabled>
   <support_level>extended</support_level>
 ***/

#include "asterisk.h"

#include <corosync/cpg.h>
#include <corosync/cfg.h>

#include "asterisk/module.h"
#include "asterisk/logger.h"
#include "asterisk/poll-compat.h"
#include "asterisk/config.h"
#include "asterisk/event.h"
#include "asterisk/cli.h"
#include "asterisk/devicestate.h"
#include "asterisk/mwi.h"
#include "asterisk/stasis.h"
#include "asterisk/stasis_message_router.h"
#include "asterisk/stasis_system.h"
#include "asterisk/taskprocessor.h"

AST_RWLOCK_DEFINE_STATIC(event_types_lock);
AST_RWLOCK_DEFINE_STATIC(init_cpg_lock);

/*! \brief Timeout for Corosync's poll process */
#define COROSYNC_POLL_TIMEOUT          (10 * 1000)

static void publish_mwi_to_stasis(struct ast_event *event);
static void publish_device_state_to_stasis(struct ast_event *event);
static void publish_cluster_discovery_to_stasis(struct ast_event *event);

/*! \brief Join to corosync */
static int corosync_node_joined = 0;

/*! \brief All the nodes that we're aware of */
static struct ao2_container *nodes;

/*! \brief The internal topic used for message forwarding and pings */
static struct stasis_topic *corosync_aggregate_topic;

/*! \brief Our \ref stasis message router */
static struct stasis_message_router *stasis_router;

/*! \brief Internal accessor for our topic */
static struct stasis_topic *corosync_topic(void)
{
   return corosync_aggregate_topic;
}

struct corosync_node {
   /*! The corosync ID */
   int id;
   /*! The Asterisk EID */
   struct ast_eid eid;
   /*! The IP address of the node */
   struct ast_sockaddr addr;
};

/*! \brief Corosync ipc dispatch/request and reply size */
#define COROSYNC_IPC_BUFFER_SIZE          (8192 * 128)

/*! \brief Version of pthread_create to ensure stack is large enough */
#define corosync_pthread_create_background(a, b, c, d)            \
   ast_pthread_create_stack(a, b, c, d,               \
      (AST_BACKGROUND_STACKSIZE + (3 * COROSYNC_IPC_BUFFER_SIZE)),   \
      __FILE__, __FUNCTION__, __LINE__, #c)

static struct corosync_node *corosync_node_alloc(struct ast_event *event)
{
   struct corosync_node *node;

   node = ao2_alloc_options(sizeof(*node), NULL, AO2_ALLOC_OPT_LOCK_NOLOCK);
   if (!node) {
      return NULL;
   }

   memcpy(&node->eid, (struct ast_eid *)ast_event_get_ie_raw(event, AST_EVENT_IE_EID), sizeof(node->eid));
   node->id = ast_event_get_ie_uint(event, AST_EVENT_IE_NODE_ID);
   ast_sockaddr_parse(&node->addr, ast_event_get_ie_str(event, AST_EVENT_IE_LOCAL_ADDR), PARSE_PORT_IGNORE);

   return node;
}

static int corosync_node_hash_fn(const void *obj, const int flags)
{
   const struct corosync_node *node;
   const int *id;

   switch (flags & OBJ_SEARCH_MASK) {
   case OBJ_SEARCH_KEY:
      id = obj;
      break;
   case OBJ_SEARCH_OBJECT:
      node = obj;
      id = &node->id;
      break;
   default:
      ast_assert(0);
      return 0;
   }
   return *id;
}

static int corosync_node_cmp_fn(void *obj, void *arg, int flags)
{
   struct corosync_node *left = obj;
   struct corosync_node *right = arg;
   const int *id = arg;
   int cmp;

   switch (flags & OBJ_SEARCH_MASK) {
   case OBJ_SEARCH_OBJECT:
      id = &right->id;
      /* Fall through */
   case OBJ_SEARCH_KEY:
      cmp = (left->id == *id);
      break;
   case OBJ_SEARCH_PARTIAL_KEY:
      cmp = (left->id == right->id);
      break;
   default:
      /* Sort can only work on something with a full or partial key. */
      ast_assert(0);
      cmp = 1;
      break;
   }
   return cmp ? CMP_MATCH : 0;
}


/*! \brief A payload wrapper around a corosync ping event */
struct corosync_ping_payload {
   /*! The corosync ping event being passed over \ref stasis */
   struct ast_event *event;
};

/*! \brief Destructor for the \ref corosync_ping_payload wrapper object */
static void corosync_ping_payload_dtor(void *obj)
{
   struct corosync_ping_payload *payload = obj;

   ast_free(payload->event);
}

/*! \brief Convert a Corosync PING to a \ref ast_event */
static struct ast_event *corosync_ping_to_event(struct stasis_message *message)
{
   struct corosync_ping_payload *payload;
   struct ast_event *event;
   struct ast_eid *event_eid;

   if (!message) {
      return NULL;
   }

   payload = stasis_message_data(message);

   if (!payload->event) {
      return NULL;
   }

   event_eid = (struct ast_eid *)ast_event_get_ie_raw(payload->event, AST_EVENT_IE_EID);

   event = ast_event_new(AST_EVENT_PING,
            AST_EVENT_IE_EID, AST_EVENT_IE_PLTYPE_RAW, event_eid, sizeof(*event_eid),
            AST_EVENT_IE_END);

   return event;
}

STASIS_MESSAGE_TYPE_DEFN_LOCAL(corosync_ping_message_type,
   .to_event = corosync_ping_to_event, );

/*! \brief Publish a Corosync ping to \ref stasis */
static void publish_corosync_ping_to_stasis(struct ast_event *event)
{
   struct corosync_ping_payload *payload;
   struct stasis_message *message;
   struct ast_eid *event_eid;

   ast_assert(ast_event_get_type(event) == AST_EVENT_PING);
   ast_assert(event != NULL);

   if (!corosync_ping_message_type()) {
      return;
   }

   payload = ao2_t_alloc(sizeof(*payload), corosync_ping_payload_dtor, "Create ping payload");
   if (!payload) {
      return;
   }
   event_eid = (struct ast_eid *)ast_event_get_ie_raw(event, AST_EVENT_IE_EID);
   payload->event = ast_event_new(AST_EVENT_PING,
            AST_EVENT_IE_EID, AST_EVENT_IE_PLTYPE_RAW, event_eid, sizeof(*event_eid),
            AST_EVENT_IE_END);

   message = stasis_message_create(corosync_ping_message_type(), payload);
   if (!message) {
      ao2_t_ref(payload, -1, "Destroy payload on off nominal");
      return;
   }

   stasis_publish(corosync_topic(), message);

   ao2_t_ref(payload, -1, "Hand ref to stasis");
   ao2_t_ref(message, -1, "Hand ref to stasis");
}

static struct {
   const char *name;
   struct stasis_forward *sub;
   unsigned char publish;
   unsigned char publish_default;
   unsigned char subscribe;
   unsigned char subscribe_default;
   struct stasis_topic *(* topic_fn)(void);
   struct stasis_cache *(* cache_fn)(void);
   struct stasis_message_type *(* message_type_fn)(void);
   void (* publish_to_stasis)(struct ast_event *);
} event_types[] = {
   [AST_EVENT_MWI] = { .name = "mwi",
                       .topic_fn = ast_mwi_topic_all,
                       .cache_fn = ast_mwi_state_cache,
                       .message_type_fn = ast_mwi_state_type,
                       .publish_to_stasis = publish_mwi_to_stasis, },
   [AST_EVENT_DEVICE_STATE_CHANGE] = { .name = "device_state",
                                       .topic_fn = ast_device_state_topic_all,
                                       .cache_fn = ast_device_state_cache,
                                       .message_type_fn = ast_device_state_message_type,
                                       .publish_to_stasis = publish_device_state_to_stasis, },
   [AST_EVENT_PING] = { .name = "ping",
                        .publish_default = 1,
                        .subscribe_default = 1,
                        .topic_fn = corosync_topic,
                        .message_type_fn = corosync_ping_message_type,
                        .publish_to_stasis = publish_corosync_ping_to_stasis, },
   [AST_EVENT_CLUSTER_DISCOVERY] = { .name = "cluster_discovery",
                                     .publish_default = 1,
                                     .subscribe_default = 1,
                                     .topic_fn = ast_system_topic,
                                     .message_type_fn = ast_cluster_discovery_type,
                                     .publish_to_stasis = publish_cluster_discovery_to_stasis, },
};

static struct {
   pthread_t id;
   int alert_pipe[2];
   unsigned int stop:1;
} dispatch_thread = {
   .id = AST_PTHREADT_NULL,
   .alert_pipe = { -1, -1 },
};

static cpg_handle_t cpg_handle;
static corosync_cfg_handle_t cfg_handle;

#ifdef HAVE_COROSYNC_CFG_STATE_TRACK
static void cfg_state_track_cb(
      corosync_cfg_state_notification_buffer_t *notification_buffer,
      cs_error_t error);
#endif /* HAVE_COROSYNC_CFG_STATE_TRACK */

static void cfg_shutdown_cb(corosync_cfg_handle_t cfg_handle,
      corosync_cfg_shutdown_flags_t flags);

static corosync_cfg_callbacks_t cfg_callbacks = {
#ifdef HAVE_COROSYNC_CFG_STATE_TRACK
   .corosync_cfg_state_track_callback = cfg_state_track_cb,
#endif /* HAVE_COROSYNC_CFG_STATE_TRACK */
   .corosync_cfg_shutdown_callback = cfg_shutdown_cb,
};

/*! \brief Publish cluster discovery to \ref stasis */
static void publish_cluster_discovery_to_stasis_full(struct corosync_node *node, int joined)
{
   struct ast_json *json;
   struct ast_json_payload *payload;
   struct stasis_message *message;
   char eid[18];
   const char *addr;

   ast_eid_to_str(eid, sizeof(eid), &node->eid);
   addr = ast_sockaddr_stringify_addr(&node->addr);

   ast_log(AST_LOG_NOTICE, "Node %u (%s) at %s %s the cluster\n",
      node->id,
      eid,
      addr,
      joined ? "joined" : "left");

   json = ast_json_pack("{s: s, s: i, s: s, s: i}",
      "address", addr,
      "node_id", node->id,
      "eid", eid,
      "joined", joined);
   if (!json) {
      return;
   }

   payload = ast_json_payload_create(json);
   if (!payload) {
      ast_json_unref(json);
      return;
   }

   message = stasis_message_create(ast_cluster_discovery_type(), payload);
   if (!message) {
      ast_json_unref(json);
      ao2_ref(payload, -1);
      return;
   }

   stasis_publish(ast_system_topic(), message);
   ast_json_unref(json);
   ao2_ref(payload, -1);
   ao2_ref(message, -1);
}

static void send_cluster_notify(void);

/*! \brief Publish a received cluster discovery \ref ast_event to \ref stasis */
static void publish_cluster_discovery_to_stasis(struct ast_event *event)
{
   struct corosync_node *node;
   int id = ast_event_get_ie_uint(event, AST_EVENT_IE_NODE_ID);
   struct ast_eid *event_eid;

   ast_assert(ast_event_get_type(event) == AST_EVENT_CLUSTER_DISCOVERY);

   event_eid = (struct ast_eid *)ast_event_get_ie_raw(event, AST_EVENT_IE_EID);
   if (!event_eid || !ast_eid_cmp(&ast_eid_default, event_eid)) {
      /* Don't feed events back in that originated locally. */
      return;
   }

   ao2_lock(nodes);
   node = ao2_find(nodes, &id, OBJ_SEARCH_KEY | OBJ_NOLOCK);
   if (node) {
      /* We already know about this node */
      ao2_unlock(nodes);
      ao2_ref(node, -1);
      return;
   }

   node = corosync_node_alloc(event);
   if (!node) {
      ao2_unlock(nodes);
      return;
   }
   ao2_link_flags(nodes, node, OBJ_NOLOCK);
   ao2_unlock(nodes);

   publish_cluster_discovery_to_stasis_full(node, 1);

   ao2_ref(node, -1);

   /*
    * When we get news that someone else has joined, we need to let them
    * know we exist as well.
    */
   send_cluster_notify();
}

/*! \brief Publish a received MWI \ref ast_event to \ref stasis */
static void publish_mwi_to_stasis(struct ast_event *event)
{
   const char *mailbox;
   const char *context;
   unsigned int new_msgs;
   unsigned int old_msgs;
   struct ast_eid *event_eid;

   ast_assert(ast_event_get_type(event) == AST_EVENT_MWI);

   mailbox = ast_event_get_ie_str(event, AST_EVENT_IE_MAILBOX);
   context = ast_event_get_ie_str(event, AST_EVENT_IE_CONTEXT);
   new_msgs = ast_event_get_ie_uint(event, AST_EVENT_IE_NEWMSGS);
   old_msgs = ast_event_get_ie_uint(event, AST_EVENT_IE_OLDMSGS);
   event_eid = (struct ast_eid *)ast_event_get_ie_raw(event, AST_EVENT_IE_EID);

   if (ast_strlen_zero(mailbox) || ast_strlen_zero(context)) {
      return;
   }

   if (new_msgs > INT_MAX) {
      new_msgs = INT_MAX;
   }

   if (old_msgs > INT_MAX) {
      old_msgs = INT_MAX;
   }

   if (ast_publish_mwi_state_full(mailbox, context, (int)new_msgs,
                                  (int)old_msgs, NULL, event_eid)) {
      char eid[18];
      ast_eid_to_str(eid, sizeof(eid), event_eid);
      ast_log(LOG_WARNING, "Failed to publish MWI message for %s@%s from %s\n",
         mailbox, context, eid);
   }
}

/*! \brief Publish a received device state \ref ast_event to \ref stasis */
static void publish_device_state_to_stasis(struct ast_event *event)
{
   const char *device;
   enum ast_device_state state;
   unsigned int cachable;
   struct ast_eid *event_eid;

   ast_assert(ast_event_get_type(event) == AST_EVENT_DEVICE_STATE_CHANGE);

   device = ast_event_get_ie_str(event, AST_EVENT_IE_DEVICE);
   state = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
   cachable = ast_event_get_ie_uint(event, AST_EVENT_IE_CACHABLE);
   event_eid = (struct ast_eid *)ast_event_get_ie_raw(event, AST_EVENT_IE_EID);

   if (ast_strlen_zero(device)) {
      return;
   }

   if (ast_publish_device_state_full(device, state, cachable, event_eid)) {
      char eid[18];
      ast_eid_to_str(eid, sizeof(eid), event_eid);
      ast_log(LOG_WARNING, "Failed to publish device state message for %s from %s\n",
         device, eid);
   }
}

static void cpg_deliver_cb(cpg_handle_t handle, const struct cpg_name *group_name,
      uint32_t nodeid, uint32_t pid, void *msg, size_t msg_len);

static void cpg_confchg_cb(cpg_handle_t handle, const struct cpg_name *group_name,
      const struct cpg_address *member_list, size_t member_list_entries,
      const struct cpg_address *left_list, size_t left_list_entries,
      const struct cpg_address *joined_list, size_t joined_list_entries);

static cpg_callbacks_t cpg_callbacks = {
   .cpg_deliver_fn = cpg_deliver_cb,
   .cpg_confchg_fn = cpg_confchg_cb,
};

#ifdef HAVE_COROSYNC_CFG_STATE_TRACK
static void cfg_state_track_cb(
      corosync_cfg_state_notification_buffer_t *notification_buffer,
      cs_error_t error)
{
}
#endif /* HAVE_COROSYNC_CFG_STATE_TRACK */

static void cfg_shutdown_cb(corosync_cfg_handle_t cfg_handle,
      corosync_cfg_shutdown_flags_t flags)
{
}

static void cpg_deliver_cb(cpg_handle_t handle, const struct cpg_name *group_name,
      uint32_t nodeid, uint32_t pid, void *msg, size_t msg_len)
{
   struct ast_event *event;
   void (*publish_handler)(struct ast_event *) = NULL;
   enum ast_event_type event_type;
   struct ast_eid *event_eid;

   if (msg_len < ast_event_minimum_length()) {
      ast_debug(1, "Ignoring event that's too small. %u < %u\n",
         (unsigned int) msg_len,
         (unsigned int) ast_event_minimum_length());
      return;
   }

   event_eid = (struct ast_eid *)ast_event_get_ie_raw(msg, AST_EVENT_IE_EID);
   if (!event_eid || !ast_eid_cmp(&ast_eid_default, event_eid)) {
      /* Don't feed events back in that originated locally. */
      return;
   }

   event_type = ast_event_get_type(msg);
   if (event_type > AST_EVENT_TOTAL) {
      /* Egads, we don't support this */
      return;
   }

   ast_rwlock_rdlock(&event_types_lock);
   ast_debug(5, "cpg_deliver_cb rdlock\n");
   publish_handler = event_types[event_type].publish_to_stasis;
   if (!event_types[event_type].subscribe || !publish_handler) {
      /* We are not configured to subscribe to these events or
         we have no way to publish it internally. */
      ast_rwlock_unlock(&event_types_lock);
      ast_debug(5, "cpg_deliver_cb unlock\n");
      return;
   }
   ast_rwlock_unlock(&event_types_lock);
   ast_debug(5, "cpg_deliver_cb unlock\n");

   if (!(event = ast_malloc(msg_len))) {
      return;
   }

   memcpy(event, msg, msg_len);

   if (event_type == AST_EVENT_PING) {
      const struct ast_eid *eid;
      char buf[128] = "";

      eid = (struct ast_eid *)ast_event_get_ie_raw(event, AST_EVENT_IE_EID);
      ast_eid_to_str(buf, sizeof(buf), (struct ast_eid *) eid);
      ast_log(LOG_NOTICE, "Got event PING from server with EID: '%s'\n", buf);
   }
   ast_debug(5, "Publishing event %s (%u) to stasis\n",
      ast_event_get_type_name(event), event_type);
   publish_handler(event);
   ast_free(event);
}

static void publish_event_to_corosync(struct ast_event *event)
{
   cs_error_t cs_err;
   struct iovec iov;

   iov.iov_base = (void *)event;
   iov.iov_len = ast_event_get_size(event);

   ast_debug(5, "Publishing event %s (%u) to corosync\n",
      ast_event_get_type_name(event), ast_event_get_type(event));

   /* The stasis subscription will only exist if we are configured to publish
    * these events, so just send away. */
   if (corosync_node_joined && !ast_rwlock_tryrdlock(&init_cpg_lock)) {
      ast_debug(5, "publish_event_to_corosync rdlock\n");
      if ((cs_err = cpg_mcast_joined(cpg_handle, CPG_TYPE_FIFO, &iov, 1)) != CS_OK) {
         ast_log(LOG_WARNING, "CPG mcast failed (%u) for event %s (%u)\n",
            cs_err, ast_event_get_type_name(event), ast_event_get_type(event));
      }
      ast_rwlock_unlock(&init_cpg_lock);
      ast_debug(5, "publish_event_to_corosync unlock\n");
   } else {
      ast_log(LOG_WARNING, "CPG mcast not executed for event %s (%u): initializing CPG.\n",
            ast_event_get_type_name(event), ast_event_get_type(event));
   }
}

static void publish_to_corosync(struct stasis_message *message)
{
   struct ast_event *event;
   struct ast_eid *event_eid;

   event = stasis_message_to_event(message);
   if (!event) {
      return;
   }

   event_eid = (struct ast_eid *)ast_event_get_ie_raw(event, AST_EVENT_IE_EID);
   if (!event_eid || ast_eid_cmp(&ast_eid_default, event_eid)) {
      /* If the event didn't originate from this server, don't send it back out. */
      ast_event_destroy(event);
      return;
   }

   if (ast_event_get_type(event) == AST_EVENT_PING) {
      const struct ast_eid *eid;
      char buf[128] = "";

      eid = (struct ast_eid *)ast_event_get_ie_raw(event, AST_EVENT_IE_EID);
      ast_eid_to_str(buf, sizeof(buf), (struct ast_eid *) eid);
      ast_log(LOG_NOTICE, "Sending event PING from this server with EID: '%s'\n", buf);
   }

   publish_event_to_corosync(event);
   ast_event_destroy(event);
}

static void stasis_message_cb(void *data, struct stasis_subscription *sub, struct stasis_message *message)
{
   if (!message) {
      return;
   }

   publish_to_corosync(message);
}

static int dump_cache_cb(void *obj, void *arg, int flags)
{
   struct stasis_message *message = obj;

   if (!message) {
      return 0;
   }

   publish_to_corosync(message);

   return 0;
}

static int clear_node_cache(void *obj, void *arg, int flags)
{
   struct stasis_message *cached_msg = obj;
   struct stasis_topic *topic = arg;
   struct stasis_message *msg;
   struct ast_eid *msg_eid;

   if (!cached_msg) {
      return 0;
   }

   msg_eid = (struct ast_eid *)stasis_message_eid(cached_msg);
   if(msg_eid && ast_eid_cmp(&ast_eid_default, msg_eid))
   {
      msg = stasis_cache_clear_create(cached_msg);
      if (msg) {
         stasis_publish(topic, msg);
         ao2_cleanup(msg);
      }
   }

   return 0;
}

static void cpg_confchg_cb(cpg_handle_t handle, const struct cpg_name *group_name,
      const struct cpg_address *member_list, size_t member_list_entries,
      const struct cpg_address *left_list, size_t left_list_entries,
      const struct cpg_address *joined_list, size_t joined_list_entries)
{
   unsigned int i;


   for (i = 0; i < left_list_entries; i++) {
      const struct cpg_address *cpg_node = &left_list[i];
      struct corosync_node* node;
      unsigned int j;

      node = ao2_find(nodes, &cpg_node->nodeid, OBJ_UNLINK | OBJ_SEARCH_KEY);
      if (!node) {
         continue;
      }

      for (j = 0; j < ARRAY_LEN(event_types); j++) {
         struct ao2_container *messages;
         int messages_count;

         ast_rwlock_rdlock(&event_types_lock);
         ast_debug(5, "cpg_confchg_cb rdlock\n");
         if (!event_types[j].subscribe) {
            ast_rwlock_unlock(&event_types_lock);
            ast_debug(5, "cpg_confchg_cb unlock\n");
            continue;
         }

         if (!event_types[j].cache_fn || !event_types[j].message_type_fn) {
            ast_rwlock_unlock(&event_types_lock);
            ast_debug(5, "cpg_confchg_cb unlock\n");
            continue;
         }
         ast_rwlock_unlock(&event_types_lock);
         ast_debug(5, "cpg_confchg_cb unlock\n");

         messages = stasis_cache_dump_by_eid(event_types[j].cache_fn(), event_types[j].message_type_fn(), &node->eid);

         messages_count = ao2_container_count(messages);
         ast_log(LOG_NOTICE, "Clearing %i events of type %s of node %i from stasis cache.\n", messages_count, event_types[j].name, node->id);
         ao2_callback(messages, OBJ_NODATA, clear_node_cache, event_types[j].topic_fn());
         ast_log(LOG_NOTICE, "Cleared events of type %s from stasis cache.\n", event_types[j].name);

         ao2_t_ref(messages, -1, "Dispose of flushed cache");
      }

      publish_cluster_discovery_to_stasis_full(node, 0);
      ao2_ref(node, -1);
   }

   /* If any new nodes have joined, dump our cache of events we are publishing
    * that originated from this server. */
   if (!joined_list_entries) {
      return;
   }

   for (i = 0; i < ARRAY_LEN(event_types); i++) {
      struct ao2_container *messages;
      int messages_count;

      ast_rwlock_rdlock(&event_types_lock);
      ast_debug(5, "cpg_confchg_cb rdlock\n");
      if (!event_types[i].publish) {
         ast_rwlock_unlock(&event_types_lock);
         ast_debug(5, "cpg_confchg_cb unlock\n");
         continue;
      }

      if (!event_types[i].cache_fn || !event_types[i].message_type_fn) {
         ast_rwlock_unlock(&event_types_lock);
         ast_debug(5, "cpg_confchg_cb unlock\n");
         continue;
      }
      ast_rwlock_unlock(&event_types_lock);
      ast_debug(5, "cpg_confchg_cb unlock\n");

      messages = stasis_cache_dump_by_eid(event_types[i].cache_fn(), event_types[i].message_type_fn(), &ast_eid_default);

      messages_count = ao2_container_count(messages);
      ast_log(LOG_NOTICE, "Sending %i events of type %s to corosync.\n", messages_count, event_types[i].name);
      ao2_callback(messages, OBJ_NODATA, dump_cache_cb, NULL);
      ast_log(LOG_NOTICE, "Sent events of type %s to corosync.\n", event_types[i].name);

      ao2_t_ref(messages, -1, "Dispose of dumped cache");
   }
}

/*! \brief Informs the cluster of our EID and our IP addresses */
static void send_cluster_notify(void)
{
   struct ast_event *event;
   unsigned int node_id;
   cs_error_t cs_err;
   corosync_cfg_node_address_t corosync_addr;
   int num_addrs = 0;
   struct sockaddr *sa;
   size_t sa_len;
   char buf[128];
   int res;

   if (!ast_rwlock_tryrdlock(&init_cpg_lock)) {
      ast_debug(5, "send_cluster_notify rdlock\n");

      if ((cs_err = corosync_cfg_local_get(cfg_handle, &node_id)) != CS_OK) {
         ast_log(LOG_WARNING, "Failed to extract Corosync node ID for this node. Not informing cluster of existance.\n");
         return;
      }

      if (((cs_err = corosync_cfg_get_node_addrs(cfg_handle, node_id, 1, &num_addrs, &corosync_addr)) != CS_OK) || (num_addrs < 1)) {
         ast_log(LOG_WARNING, "Failed to get local Corosync address. Not informing cluster of existance.\n");
         return;
      }

      ast_rwlock_unlock(&init_cpg_lock);
      ast_debug(5, "send_cluster_notify unlock\n");
   }

   sa = (struct sockaddr *)corosync_addr.address;
   sa_len = (size_t)corosync_addr.address_length;
   if ((res = getnameinfo(sa, sa_len, buf, sizeof(buf), NULL, 0, NI_NUMERICHOST))) {
      ast_log(LOG_WARNING, "Failed to determine name of local Corosync address: %s (%d). Not informing cluster of existance.\n",
         gai_strerror(res), res);
      return;
   }

   event = ast_event_new(AST_EVENT_CLUSTER_DISCOVERY,
                AST_EVENT_IE_NODE_ID, AST_EVENT_IE_PLTYPE_UINT, node_id,
                AST_EVENT_IE_LOCAL_ADDR, AST_EVENT_IE_PLTYPE_STR, buf,
                AST_EVENT_IE_END);
   publish_event_to_corosync(event);
   ast_event_destroy(event);
}

static void *dispatch_thread_handler(void *data)
{
   cs_error_t cs_err;
   struct pollfd pfd[3] = {
      { .events = POLLIN, },
      { .events = POLLIN, },
      { .events = POLLIN, },
   };

   if (!ast_rwlock_tryrdlock(&init_cpg_lock)) {
      ast_debug(5, "dispatch_thread_handler rdlock\n");
      if ((cs_err = cpg_fd_get(cpg_handle, &pfd[0].fd)) != CS_OK) {
         ast_log(LOG_ERROR, "Failed to get CPG fd.  This module is now broken.\n");
         ast_rwlock_unlock(&init_cpg_lock);
         ast_debug(5, "dispatch_thread_handler unlock\n");
         return NULL;
      }

      if ((cs_err = corosync_cfg_fd_get(cfg_handle, &pfd[1].fd)) != CS_OK) {
         ast_log(LOG_ERROR, "Failed to get CFG fd.  This module is now broken.\n");
         ast_rwlock_unlock(&init_cpg_lock);
         ast_debug(5, "dispatch_thread_handler unlock\n");
         return NULL;
      }

      pfd[2].fd = dispatch_thread.alert_pipe[0];
      ast_rwlock_unlock(&init_cpg_lock);
      ast_debug(5, "dispatch_thread_handler unlock\n");
   } else {
      ast_log(LOG_ERROR, "Failed to get fd: initiliazing CPG.  This module is now broken.\n");
      return NULL;
   }
   send_cluster_notify();
   while (!dispatch_thread.stop) {
      int res;

      cs_err = CS_OK;

      pfd[0].revents = 0;
      pfd[1].revents = 0;
      pfd[2].revents = 0;

      res = ast_poll(pfd, ARRAY_LEN(pfd), COROSYNC_POLL_TIMEOUT);
      if (res == -1 && errno != EINTR && errno != EAGAIN) {
         ast_log(LOG_ERROR, "poll() error: %s (%d)\n", strerror(errno), errno);
         cs_err = CS_ERR_BAD_HANDLE;
      } else if (res == 0) {
         unsigned int local_nodeid;

         if (!ast_rwlock_tryrdlock(&init_cpg_lock)) {
            ast_debug(5, "dispatch_thread_handler rdlock\n");
            if ((cs_err = cpg_local_get(cpg_handle, &local_nodeid)) == CS_OK) {
               struct cpg_name name;
               struct cpg_address address[CPG_MEMBERS_MAX];
               int entries = CPG_MEMBERS_MAX;

               ast_copy_string(name.value, "asterisk", sizeof(name.value));
               name.length = strlen(name.value);
               if ((cs_err = cpg_membership_get(cpg_handle, &name, address, &entries)) == CS_OK) {
                  int i;
                  int found = 0;

                  ast_debug(1, "CPG group has %i node membership\n", entries);
                  for (i = 0; (i < entries) && !found; i++) {
                     if (address[i].nodeid == local_nodeid)
                        found = 1;
                  }
                  if (!found) {
                     ast_log(LOG_WARNING, "Failed to check CPG node membership\n");
                     corosync_node_joined = 0;
                     cs_err = CS_ERR_BAD_HANDLE;
                  }
               } else {
                  ast_log(LOG_WARNING, "Failed to get CPG node membership: %u\n", cs_err);
                  corosync_node_joined = 0;
                  cs_err = CS_ERR_BAD_HANDLE;
               }
            } else {
               ast_log(LOG_WARNING, "Failed to get CPG local node id: %u\n", cs_err);
               corosync_node_joined = 0;
               cs_err = CS_ERR_BAD_HANDLE;
            }
            ast_rwlock_unlock(&init_cpg_lock);
            ast_debug(5, "dispatch_thread_handler unlock\n");
         } else {
            ast_log(LOG_WARNING, "Failed to check CPG node membership: initializing CPG.\n");
            corosync_node_joined = 0;
            cs_err = CS_ERR_BAD_HANDLE;
         }
      } else {
         if (!ast_rwlock_tryrdlock(&init_cpg_lock)) {
            ast_debug(5, "dispatch_thread_handler rdlock\n");
            if (pfd[0].revents & POLLIN) {
               if ((cs_err = cpg_dispatch(cpg_handle, CS_DISPATCH_ALL)) != CS_OK) {
                  ast_log(LOG_WARNING, "Failed CPG dispatch: %u\n", cs_err);
               }
            }

            if (pfd[1].revents & POLLIN) {
               if ((cs_err = corosync_cfg_dispatch(cfg_handle, CS_DISPATCH_ALL)) != CS_OK) {
                  ast_log(LOG_WARNING, "Failed CFG dispatch: %u\n", cs_err);
               }
            }
            ast_rwlock_unlock(&init_cpg_lock);
            ast_debug(5, "dispatch_thread_handler unlock\n");
         } else {
            ast_log(LOG_WARNING, "Failed to dispatch: initializing CPG.\n");
         }
      }
      if (cs_err == CS_ERR_LIBRARY || cs_err == CS_ERR_BAD_HANDLE) {

         /* If corosync gets restarted out from under Asterisk, try to recover. */

         ast_log(LOG_NOTICE, "Attempting to recover from corosync failure.\n");

         if (!ast_rwlock_trywrlock(&init_cpg_lock)) {
            struct cpg_name name;
            ast_debug(5, "dispatch_thread_handler wrlock\n");

            corosync_node_joined = 0;
            if (cpg_handle && (cs_err = cpg_finalize(cpg_handle)) != CS_OK) {
               ast_log(LOG_ERROR, "Failed to finalize cpg (%d)\n", (int) cs_err);
            }

            if (cfg_handle && (cs_err = corosync_cfg_finalize(cfg_handle)) != CS_OK) {
               ast_log(LOG_ERROR, "Failed to finalize cfg (%d)\n", (int) cs_err);
            }

            if ((cs_err = corosync_cfg_initialize(&cfg_handle, &cfg_callbacks)) != CS_OK) {
               ast_log(LOG_ERROR, "Failed to initialize cfg (%d)\n", (int) cs_err);
               ast_rwlock_unlock(&init_cpg_lock);
               ast_debug(5, "dispatch_thread_handler unlock\n");
               sleep(5);
               continue;
            }

            if ((cs_err = cpg_initialize(&cpg_handle, &cpg_callbacks) != CS_OK)) {
               ast_log(LOG_ERROR, "Failed to initialize cpg (%d)\n", (int) cs_err);
               ast_rwlock_unlock(&init_cpg_lock);
               ast_debug(5, "dispatch_thread_handler unlock\n");
               sleep(5);
               continue;
            }

            if ((cs_err = cpg_fd_get(cpg_handle, &pfd[0].fd)) != CS_OK) {
               ast_log(LOG_ERROR, "Failed to get CPG fd.\n");
               ast_rwlock_unlock(&init_cpg_lock);
               ast_debug(5, "dispatch_thread_handler unlock\n");
               sleep(5);
               continue;
            }

            if ((cs_err = corosync_cfg_fd_get(cfg_handle, &pfd[1].fd)) != CS_OK) {
               ast_log(LOG_ERROR, "Failed to get CFG fd.\n");
               ast_rwlock_unlock(&init_cpg_lock);
               ast_debug(5, "dispatch_thread_handler unlock\n");
               sleep(5);
               continue;
            }

            ast_copy_string(name.value, "asterisk", sizeof(name.value));
            name.length = strlen(name.value);
            if ((cs_err = cpg_join(cpg_handle, &name)) != CS_OK) {
               ast_log(LOG_ERROR, "Failed to join cpg (%d)\n", (int) cs_err);
               ast_rwlock_unlock(&init_cpg_lock);
               ast_debug(5, "dispatch_thread_handler unlock\n");
               sleep(5);
               continue;
            }
            corosync_node_joined = 1;
            ast_rwlock_unlock(&init_cpg_lock);
            ast_debug(5, "dispatch_thread_handler unlock\n");
            ast_log(LOG_NOTICE, "Corosync recovery complete.\n");
            send_cluster_notify();
         } else {
            ast_log(LOG_NOTICE, "Failed to recover from corosync failure: initializing CPG.\n");
         }
      }
   }

   return NULL;
}

static char *corosync_show_members(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   cs_error_t cs_err;
   cpg_iteration_handle_t cpg_iter;
   struct cpg_iteration_description_t cpg_desc;
   unsigned int i;

   switch (cmd) {
   case CLI_INIT:
      e->command = "corosync show members";
      e->usage =
         "Usage: corosync show members\n"
         "       Show corosync cluster members\n";
      return NULL;

   case CLI_GENERATE:
      return NULL;   /* no completion */
   }

   if (a->argc != e->args) {
      return CLI_SHOWUSAGE;
   }

   if (!ast_rwlock_tryrdlock(&init_cpg_lock)) {
      ast_debug(5, "corosync_show_members rdlock\n");
      cs_err = cpg_iteration_initialize(cpg_handle, CPG_ITERATION_ALL, NULL, &cpg_iter);

      if (cs_err != CS_OK) {
         ast_cli(a->fd, "Failed to initialize CPG iterator: %u.\n", cs_err);
         cpg_iteration_finalize(cpg_iter);
         ast_rwlock_unlock(&init_cpg_lock);
         ast_debug(5, "corosync_show_members unlock\n");
         return CLI_FAILURE;
      }

      ast_cli(a->fd, "\n"
               "=============================================================\n"
               "=== Cluster members =========================================\n"
               "=============================================================\n"
               "===\n");

      for (i = 1, cs_err = cpg_iteration_next(cpg_iter, &cpg_desc);
            cs_err == CS_OK;
            cs_err = cpg_iteration_next(cpg_iter, &cpg_desc), i++) {
   #ifdef HAVE_COROSYNC_CFG_STATE_TRACK
         corosync_cfg_node_address_t addrs[8];
         int num_addrs = 0;
         unsigned int j;
   #endif

         ast_cli(a->fd, "=== Node %u\n", i);
         ast_cli(a->fd, "=== --> Group: %s\n", cpg_desc.group.value);

   #ifdef HAVE_COROSYNC_CFG_STATE_TRACK
         /*
         * Corosync 2.x cfg lib needs to allocate 1M on stack after calling
         * corosync_cfg_get_node_addrs. netconsole thread has allocated only 0.5M
         * resulting in crash.
         */
         cs_err = corosync_cfg_get_node_addrs(cfg_handle, cpg_desc.nodeid,
               ARRAY_LEN(addrs), &num_addrs, addrs);
         if (cs_err != CS_OK) {
            ast_log(LOG_WARNING, "Failed to get node addresses\n");
            continue;
         }

         for (j = 0; j < num_addrs; j++) {
            struct sockaddr *sa = (struct sockaddr *) addrs[j].address;
            size_t sa_len = (size_t) addrs[j].address_length;
            char buf[128];

            getnameinfo(sa, sa_len, buf, sizeof(buf), NULL, 0, NI_NUMERICHOST);

            ast_cli(a->fd, "=== --> Address %u: %s\n", j + 1, buf);
         }
   #else
         ast_cli(a->fd, "=== --> Nodeid: %"PRIu32"\n", cpg_desc.nodeid);
   #endif
      }

      ast_cli(a->fd, "===\n"
               "=============================================================\n"
               "\n");

      cpg_iteration_finalize(cpg_iter);
      ast_rwlock_unlock(&init_cpg_lock);
      ast_debug(5, "corosync_show_members unlock\n");
   } else {
      ast_cli(a->fd, "Failed to initialize CPG iterator: initializing CPG.\n");
   }

   return CLI_SUCCESS;
}

static char *corosync_ping(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct ast_event *event;

   switch (cmd) {
   case CLI_INIT:
      e->command = "corosync ping";
      e->usage =
         "Usage: corosync ping\n"
         "       Send a test ping to the cluster.\n"
         "A NOTICE will be in the log for every ping received\n"
         "on a server.\n  If you send a ping, you should see a NOTICE\n"
         "in the log for every server in the cluster.\n";
      return NULL;

   case CLI_GENERATE:
      return NULL;   /* no completion */
   }

   if (a->argc != e->args) {
      return CLI_SHOWUSAGE;
   }

   event = ast_event_new(AST_EVENT_PING, AST_EVENT_IE_END);

   if (!event) {
      return CLI_FAILURE;
   }

   event_types[AST_EVENT_PING].publish_to_stasis(event);

   ast_event_destroy(event);
   return CLI_SUCCESS;
}

static char *corosync_show_config(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   unsigned int i;

   switch (cmd) {
   case CLI_INIT:
      e->command = "corosync show config";
      e->usage =
         "Usage: corosync show config\n"
         "       Show configuration loaded from res_corosync.conf\n";
      return NULL;

   case CLI_GENERATE:
      return NULL;   /* no completion */
   }

   if (a->argc != e->args) {
      return CLI_SHOWUSAGE;
   }

   ast_cli(a->fd, "\n"
               "=============================================================\n"
               "=== res_corosync config =====================================\n"
               "=============================================================\n"
               "===\n");

   ast_rwlock_rdlock(&event_types_lock);
   ast_debug(5, "corosync_show_config rdlock\n");
   for (i = 0; i < ARRAY_LEN(event_types); i++) {
      if (event_types[i].publish) {
         ast_cli(a->fd, "=== ==> Publishing Event Type: %s\n",
               event_types[i].name);
      }
      if (event_types[i].subscribe) {
         ast_cli(a->fd, "=== ==> Subscribing to Event Type: %s\n",
               event_types[i].name);
      }
   }
   ast_rwlock_unlock(&event_types_lock);
   ast_debug(5, "corosync_show_config unlock\n");

   ast_cli(a->fd, "===\n"
                  "=============================================================\n"
                  "\n");

   return CLI_SUCCESS;
}

static struct ast_cli_entry corosync_cli[] = {
   AST_CLI_DEFINE(corosync_show_config, "Show configuration"),
   AST_CLI_DEFINE(corosync_show_members, "Show cluster members"),
   AST_CLI_DEFINE(corosync_ping, "Send a test ping to the cluster"),
};

enum {
   PUBLISH,
   SUBSCRIBE,
};

static int set_event(const char *event_type, int pubsub)
{
   unsigned int i;

   for (i = 0; i < ARRAY_LEN(event_types); i++) {
      if (!event_types[i].name || strcasecmp(event_type, event_types[i].name)) {
         continue;
      }

      switch (pubsub) {
      case PUBLISH:
         event_types[i].publish = 1;
         break;
      case SUBSCRIBE:
         event_types[i].subscribe = 1;
         break;
      }

      break;
   }

   return (i == ARRAY_LEN(event_types)) ? -1 : 0;
}

static int load_general_config(struct ast_config *cfg)
{
   struct ast_variable *v;
   int res = 0;
   unsigned int i;

   ast_rwlock_wrlock(&event_types_lock);
   ast_debug(5, "load_general_config wrlock\n");

   for (i = 0; i < ARRAY_LEN(event_types); i++) {
      event_types[i].publish = event_types[i].publish_default;
      event_types[i].subscribe = event_types[i].subscribe_default;
   }

   for (v = ast_variable_browse(cfg, "general"); v && !res; v = v->next) {
      if (!strcasecmp(v->name, "publish_event")) {
         res = set_event(v->value, PUBLISH);
      } else if (!strcasecmp(v->name, "subscribe_event")) {
         res = set_event(v->value, SUBSCRIBE);
      } else {
         ast_log(LOG_WARNING, "Unknown option '%s'\n", v->name);
      }
   }

   for (i = 0; i < ARRAY_LEN(event_types); i++) {
      if (event_types[i].publish && !event_types[i].sub) {
         event_types[i].sub = stasis_forward_all(event_types[i].topic_fn(),
                                       corosync_topic());
         stasis_message_router_add(stasis_router,
                                   event_types[i].message_type_fn(),
                                   stasis_message_cb,
                                   NULL);
      } else if (!event_types[i].publish && event_types[i].sub) {
         event_types[i].sub = stasis_forward_cancel(event_types[i].sub);
         stasis_message_router_remove(stasis_router,
                                      event_types[i].message_type_fn());
      }
   }

   ast_rwlock_unlock(&event_types_lock);
   ast_debug(5, "load_general_config unlock\n");

   return res;
}

static int load_config(unsigned int reload)
{
   static const char filename[] = "res_corosync.conf";
   struct ast_config *cfg;
   const char *cat = NULL;
   struct ast_flags config_flags = { 0 };
   int res = 0;

   cfg = ast_config_load(filename, config_flags);

   if (cfg == CONFIG_STATUS_FILEMISSING || cfg == CONFIG_STATUS_FILEINVALID) {
      return -1;
   }

   while ((cat = ast_category_browse(cfg, cat))) {
      if (!strcasecmp(cat, "general")) {
         res = load_general_config(cfg);
      } else {
         ast_log(LOG_WARNING, "Unknown configuration section '%s'\n", cat);
      }
   }

   ast_config_destroy(cfg);

   return res;
}

static void cleanup_module(void)
{
   cs_error_t cs_err;
   unsigned int i;

   if (stasis_router) {

      /* Unsubscribe all topic forwards and cancel all message routes */
      for (i = 0; i < ARRAY_LEN(event_types); i++) {
         struct ao2_container *messages = NULL;
         int messages_count;
         unsigned char subscribe = 0;

         ast_rwlock_wrlock(&event_types_lock);
         ast_debug(5, "cleanup_module wrlock\n");
         subscribe = event_types[i].subscribe;

         if (event_types[i].sub) {
            event_types[i].sub = stasis_forward_cancel(event_types[i].sub);
            stasis_message_router_remove(stasis_router, event_types[i].message_type_fn());
         }
         event_types[i].publish = 0;
         event_types[i].subscribe = 0;
         ast_rwlock_unlock(&event_types_lock);
         ast_debug(5, "cleanup_module unlock\n");

         if (subscribe && event_types[i].cache_fn && event_types[i].message_type_fn) {
            messages = stasis_cache_dump_all(event_types[i].cache_fn(), event_types[i].message_type_fn());
            messages_count = ao2_container_count(messages);
            ast_log(LOG_NOTICE, "Clearing %i events of type %s of other nodes from stasis cache.\n", messages_count, event_types[i].name);
            ao2_callback(messages, OBJ_NODATA, clear_node_cache, event_types[i].topic_fn());
            ast_log(LOG_NOTICE, "Cleared events of type %s from stasis cache.\n", event_types[i].name);
            ao2_t_ref(messages, -1, "Dispose of flushed cache");
         }
      }

      stasis_message_router_unsubscribe_and_join(stasis_router);
      stasis_router = NULL;
   }

   if (corosync_aggregate_topic) {
      ao2_t_ref(corosync_aggregate_topic, -1, "Dispose of topic on cleanup");
      corosync_aggregate_topic = NULL;
   }

   STASIS_MESSAGE_TYPE_CLEANUP(corosync_ping_message_type);

   if (dispatch_thread.id != AST_PTHREADT_NULL) {
      char meepmeep = 'x';
      dispatch_thread.stop = 1;
      if (ast_carefulwrite(dispatch_thread.alert_pipe[1], &meepmeep, 1,
               5000) == -1) {
         ast_log(LOG_ERROR, "Failed to write to pipe: %s (%d)\n",
               strerror(errno), errno);
      }
      pthread_join(dispatch_thread.id, NULL);
   }

   if (dispatch_thread.alert_pipe[0] != -1) {
      close(dispatch_thread.alert_pipe[0]);
      dispatch_thread.alert_pipe[0] = -1;
   }

   if (dispatch_thread.alert_pipe[1] != -1) {
      close(dispatch_thread.alert_pipe[1]);
      dispatch_thread.alert_pipe[1] = -1;
   }

   if (!ast_rwlock_trywrlock(&init_cpg_lock)) {
      ast_debug(5, "cleanup_module wrlock\n");
      if (cpg_handle && (cs_err = cpg_finalize(cpg_handle)) != CS_OK) {
         ast_log(LOG_ERROR, "Failed to finalize cpg (%d)\n", (int) cs_err);
      }
      cpg_handle = 0;

      if (cfg_handle && (cs_err = corosync_cfg_finalize(cfg_handle)) != CS_OK) {
         ast_log(LOG_ERROR, "Failed to finalize cfg (%d)\n", (int) cs_err);
      }
      cfg_handle = 0;
      corosync_node_joined = 0;
      ast_rwlock_unlock(&init_cpg_lock);
      ast_debug(5, "cleanup_module unlock\n");
   }
   ao2_cleanup(nodes);
   nodes = NULL;
}

static int load_module(void)
{
   cs_error_t cs_err;
   struct cpg_name name;

   if (ast_eid_is_empty(&ast_eid_default)) {
      ast_log(LOG_ERROR, "Entity ID is not set.\n");
      return AST_MODULE_LOAD_DECLINE;
   }

   nodes = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0, 23,
      corosync_node_hash_fn, NULL, corosync_node_cmp_fn);
   if (!nodes) {
      goto failed;
   }

   corosync_aggregate_topic = stasis_topic_create("corosync:aggregator");
   if (!corosync_aggregate_topic) {
      ast_log(AST_LOG_ERROR, "Failed to create stasis topic for corosync\n");
      goto failed;
   }

   stasis_router = stasis_message_router_create(corosync_aggregate_topic);
   if (!stasis_router) {
      ast_log(AST_LOG_ERROR, "Failed to create message router for corosync topic\n");
      goto failed;
   }
   stasis_message_router_set_congestion_limits(stasis_router, -1,
      10 * AST_TASKPROCESSOR_HIGH_WATER_LEVEL);

   if (STASIS_MESSAGE_TYPE_INIT(corosync_ping_message_type) != 0) {
      ast_log(AST_LOG_ERROR, "Failed to initialize corosync ping message type\n");
      goto failed;
   }

   if (load_config(0)) {
      /* simply not configured is not a fatal error */
      goto failed;
   }

   if (!ast_rwlock_trywrlock(&init_cpg_lock)) {
      corosync_node_joined = 0;
      ast_debug(5, "load_module wrlock\n");
      if ((cs_err = corosync_cfg_initialize(&cfg_handle, &cfg_callbacks)) != CS_OK) {
         ast_log(LOG_ERROR, "Failed to initialize cfg: (%d)\n", (int) cs_err);
         ast_rwlock_unlock(&init_cpg_lock);
         ast_debug(5, "load_module unlock\n");
         goto failed;
      }

      if ((cs_err = cpg_initialize(&cpg_handle, &cpg_callbacks)) != CS_OK) {
         ast_log(LOG_ERROR, "Failed to initialize cpg: (%d)\n", (int) cs_err);
         ast_rwlock_unlock(&init_cpg_lock);
         ast_debug(5, "load_module unlock\n");
         goto failed;
      }

      ast_copy_string(name.value, "asterisk", sizeof(name.value));
      name.length = strlen(name.value);

      if ((cs_err = cpg_join(cpg_handle, &name)) != CS_OK) {
         ast_log(LOG_ERROR, "Failed to join: (%d)\n", (int) cs_err);
         ast_rwlock_unlock(&init_cpg_lock);
         ast_debug(5, "load_module unlock\n");
         goto failed;
      }

      if (pipe(dispatch_thread.alert_pipe) == -1) {
         ast_log(LOG_ERROR, "Failed to create alert pipe: %s (%d)\n",
               strerror(errno), errno);
         ast_rwlock_unlock(&init_cpg_lock);
         ast_debug(5, "load_module unlock\n");
         goto failed;
      }
      corosync_node_joined = 1;

      ast_rwlock_unlock(&init_cpg_lock);
      ast_debug(5, "load_module unlock\n");
      if (corosync_pthread_create_background(&dispatch_thread.id, NULL,
            dispatch_thread_handler, NULL)) {
         ast_log(LOG_ERROR, "Error starting CPG dispatch thread.\n");
         goto failed;
      }

      ast_cli_register_multiple(corosync_cli, ARRAY_LEN(corosync_cli));
   } else {
      goto failed;
   }

   return AST_MODULE_LOAD_SUCCESS;

failed:
   cleanup_module();

   return AST_MODULE_LOAD_DECLINE;
}

static int unload_module(void)
{
   ast_cli_unregister_multiple(corosync_cli, ARRAY_LEN(corosync_cli));

   cleanup_module();

   return 0;
}

AST_MODULE_INFO_STANDARD_EXTENDED(ASTERISK_GPL_KEY, "Corosync");