res_pjsip_publish_asterisk.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2014, Digium, Inc.
 *
 * Joshua Colp <[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.
 */

/*** MODULEINFO
   <depend>pjproject</depend>
   <depend>res_pjsip</depend>
   <depend>res_pjsip_outbound_publish</depend>
   <depend>res_pjsip_pubsub</depend>
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include <regex.h>

#include <pjsip.h>
#include <pjsip_simple.h>

#include "asterisk/res_pjsip.h"
#include "asterisk/res_pjsip_outbound_publish.h"
#include "asterisk/res_pjsip_pubsub.h"
#include "asterisk/module.h"
#include "asterisk/logger.h"
#include "asterisk/mwi.h"

/*** DOCUMENTATION
   <configInfo name="res_pjsip_publish_asterisk" language="en_US">
      <synopsis>SIP resource for inbound and outbound Asterisk event publications</synopsis>
      <description><para>
         <emphasis>Inbound and outbound Asterisk event publication</emphasis>
         </para>
         <para>This module allows <literal>res_pjsip</literal> to send and receive Asterisk event publications.</para>
      </description>
      <configFile name="pjsip.conf">
         <configObject name="asterisk-publication">
            <synopsis>The configuration for inbound Asterisk event publication</synopsis>
            <description><para>
               Publish is <emphasis>COMPLETELY</emphasis> separate from the rest of
               <literal>pjsip.conf</literal>.
            </para></description>
            <configOption name="devicestate_publish">
               <synopsis>Optional name of a publish item that can be used to publish a request for full device state information.</synopsis>
            </configOption>
            <configOption name="mailboxstate_publish">
               <synopsis>Optional name of a publish item that can be used to publish a request for full mailbox state information.</synopsis>
            </configOption>
            <configOption name="device_state" default="no">
               <synopsis>Whether we should permit incoming device state events.</synopsis>
            </configOption>
            <configOption name="device_state_filter">
               <synopsis>Optional regular expression used to filter what devices we accept events for.</synopsis>
            </configOption>
            <configOption name="mailbox_state" default="no">
               <synopsis>Whether we should permit incoming mailbox state events.</synopsis>
            </configOption>
            <configOption name="mailbox_state_filter">
               <synopsis>Optional regular expression used to filter what mailboxes we accept events for.</synopsis>
            </configOption>
            <configOption name="type">
               <synopsis>Must be of type 'asterisk-publication'.</synopsis>
            </configOption>
         </configObject>
      </configFile>
   </configInfo>
 ***/

/*! \brief Structure which contains Asterisk device state publisher state information */
struct asterisk_devicestate_publisher_state {
   /*! \brief The publish client to send PUBLISH messages on */
   struct ast_sip_outbound_publish_client *client;
   /*! \brief Device state subscription */
   struct stasis_subscription *device_state_subscription;
   /*! \brief Regex used for filtering outbound device state */
   regex_t device_state_regex;
   /*! \brief Device state should be filtered */
   unsigned int device_state_filter;
};

/*! \brief Structure which contains Asterisk mailbox publisher state information */
struct asterisk_mwi_publisher_state {
   /*! \brief The publish client to send PUBLISH messages on */
   struct ast_sip_outbound_publish_client *client;
   /*! \brief Mailbox state subscription */
   struct stasis_subscription *mailbox_state_subscription;
   /*! \brief Regex used for filtering outbound mailbox state */
   regex_t mailbox_state_regex;
   /*! \brief Mailbox state should be filtered */
   unsigned int mailbox_state_filter;
};

/*! \brief Structure which contains Asterisk publication information */
struct asterisk_publication_config {
   /*! \brief Sorcery object details */
   SORCERY_OBJECT(details);
   /*! \brief Stringfields */
   AST_DECLARE_STRING_FIELDS(
      /*! \brief Optional name of a device state publish item, used to request the remote side update us */
      AST_STRING_FIELD(devicestate_publish);
      /*! \brief Optional name of a mailbox state publish item, used to request the remote side update us */
      AST_STRING_FIELD(mailboxstate_publish);
   );
   /*! \brief Accept inbound device state events */
   unsigned int device_state;
   /*! \brief Regex used for filtering inbound device state */
   regex_t device_state_regex;
   /*! \brief Device state should be filtered */
   unsigned int device_state_filter;
   /*! \brief Accept inbound mailbox state events */
   unsigned int mailbox_state;
   /*! \brief Regex used for filtering inbound mailbox state */
   regex_t mailbox_state_regex;
   /*! \brief Mailbox state should be filtered */
   unsigned int mailbox_state_filter;
};

/*! \brief Destroy callback for Asterisk devicestate publisher state information from datastore */
static void asterisk_devicestate_publisher_state_destroy(void *obj)
{
   struct asterisk_devicestate_publisher_state *publisher_state = obj;

   ao2_cleanup(publisher_state->client);

   if (publisher_state->device_state_filter) {
      regfree(&publisher_state->device_state_regex);
   }
}

/*! \brief Datastore for attaching devicestate publisher state information */
static const struct ast_datastore_info asterisk_devicestate_publisher_state_datastore = {
   .type = "asterisk-devicestate-publisher",
   .destroy = asterisk_devicestate_publisher_state_destroy,
};

/*! \brief Destroy callback for Asterisk mwi publisher state information from datastore */
static void asterisk_mwi_publisher_state_destroy(void *obj)
{
   struct asterisk_mwi_publisher_state *publisher_state = obj;

   ao2_cleanup(publisher_state->client);

   if (publisher_state->mailbox_state_filter) {
      regfree(&publisher_state->mailbox_state_regex);
   }
}

/*! \brief Datastore for attaching devicestate publisher state information */
static const struct ast_datastore_info asterisk_mwi_publisher_state_datastore = {
   .type = "asterisk-mwi-publisher",
   .destroy = asterisk_mwi_publisher_state_destroy,
};

/*!
 * \brief Callback function for device state events
 * \param ast_event
 * \param data void pointer to ast_client structure
 * \return void
 */
static void asterisk_publisher_devstate_cb(void *data, struct stasis_subscription *sub, struct stasis_message *msg)
{
   struct ast_datastore *datastore = data;
   struct asterisk_devicestate_publisher_state *publisher_state = datastore->data;
   struct ast_device_state_message *dev_state;
   char eid_str[20];
   struct ast_json *json;
   char *text;
   struct ast_sip_body body = {
      .type = "application",
      .subtype = "json",
   };

   if (!stasis_subscription_is_subscribed(sub) || ast_device_state_message_type() != stasis_message_type(msg)) {
      return;
   }

   dev_state = stasis_message_data(msg);
   if (!dev_state->eid || ast_eid_cmp(&ast_eid_default, dev_state->eid)) {
      /* If the event is aggregate or didn't originate from this server, don't send it out. */
      return;
   }

   if (publisher_state->device_state_filter && regexec(&publisher_state->device_state_regex, dev_state->device, 0, NULL, 0)) {
      /* Outgoing device state has been filtered and the device name does not match */
      return;
   }

   ast_eid_to_str(eid_str, sizeof(eid_str), &ast_eid_default);
   json = ast_json_pack(
      "{ s: s, s: s, s: s, s: i, s:s }",
      "type", "devicestate",
      "device", dev_state->device,
      "state", ast_devstate_str(dev_state->state),
      "cachable", dev_state->cachable,
      "eid", eid_str);
   if (!json) {
      return;
   }

   text = ast_json_dump_string(json);
   if (!text) {
      ast_json_unref(json);
      return;
   }
   body.body_text = text;

   ast_sip_publish_client_send(publisher_state->client, &body);

   ast_json_free(text);
   ast_json_unref(json);
}

/*!
 * \brief Callback function for mailbox state events
 * \param ast_event
 * \param data void pointer to ast_client structure
 * \return void
 */
static void asterisk_publisher_mwistate_cb(void *data, struct stasis_subscription *sub, struct stasis_message *msg)
{
   struct ast_datastore *datastore = data;
   struct asterisk_mwi_publisher_state *publisher_state = datastore->data;
   struct ast_mwi_state *mwi_state;
   char eid_str[20];
   struct ast_json *json;
   char *text;
   struct ast_sip_body body = {
      .type = "application",
      .subtype = "json",
   };

   if (!stasis_subscription_is_subscribed(sub) || ast_mwi_state_type() != stasis_message_type(msg)) {
      return;
   }

   mwi_state = stasis_message_data(msg);
   if (ast_eid_cmp(&ast_eid_default, &mwi_state->eid)) {
      /* If the event is aggregate or didn't originate from this server, don't send it out. */
      return;
   }

   if (publisher_state->mailbox_state_filter && regexec(&publisher_state->mailbox_state_regex, mwi_state->uniqueid, 0, NULL, 0)) {
      /* Outgoing mailbox state has been filtered and the uniqueid does not match */
      return;
   }

   ast_eid_to_str(eid_str, sizeof(eid_str), &ast_eid_default);
   json = ast_json_pack(
      "{ s: s, s: s, s: i, s: i, s:s }",
      "type", "mailboxstate",
      "uniqueid", mwi_state->uniqueid,
      "old", mwi_state->old_msgs,
      "new", mwi_state->new_msgs,
      "eid", eid_str);
   if (!json) {
      return;
   }

   text = ast_json_dump_string(json);
   if (!text) {
      ast_json_unref(json);
      return;
   }
   body.body_text = text;

   ast_sip_publish_client_send(publisher_state->client, &body);

   ast_json_free(text);
   ast_json_unref(json);
}

static int cached_devstate_cb(void *obj, void *arg, int flags)
{
   struct stasis_message *msg = obj;
   struct ast_datastore *datastore = arg;
   struct asterisk_devicestate_publisher_state *publisher_state = datastore->data;

   asterisk_publisher_devstate_cb(arg, publisher_state->device_state_subscription, msg);

   return 0;
}

static int cached_mwistate_cb(void *obj, void *arg, int flags)
{
   struct stasis_message *msg = obj;
   struct ast_datastore *datastore = arg;
   struct asterisk_mwi_publisher_state *publisher_state = datastore->data;

   asterisk_publisher_mwistate_cb(arg, publisher_state->mailbox_state_subscription, msg);

   return 0;
}

static int build_regex(regex_t *regex, const char *text)
{
   int res;

   if ((res = regcomp(regex, text, REG_EXTENDED | REG_ICASE | REG_NOSUB))) {
      size_t len = regerror(res, regex, NULL, 0);
      char buf[len];
      regerror(res, regex, buf, len);
      ast_log(LOG_ERROR, "Could not compile regex '%s': %s\n", text, buf);
      return -1;
   }

   return 0;
}

static int asterisk_start_devicestate_publishing(struct ast_sip_outbound_publish *configuration,
   struct ast_sip_outbound_publish_client *client)
{
   RAII_VAR(struct ast_datastore *, datastore, NULL, ao2_cleanup);
   struct asterisk_devicestate_publisher_state *publisher_state;
   const char *value;
   struct ao2_container *cached;

   datastore = ast_sip_publish_client_alloc_datastore(&asterisk_devicestate_publisher_state_datastore,
      "asterisk-devicestate-publisher");
   if (!datastore) {
      return -1;
   }

   publisher_state = ast_calloc(1, sizeof(struct asterisk_devicestate_publisher_state));
   if (!publisher_state) {
      return -1;
   }
   datastore->data = publisher_state;

   value = ast_sorcery_object_get_extended(configuration, "device_state_filter");
   if (!ast_strlen_zero(value)) {
      if (build_regex(&publisher_state->device_state_regex, value)) {
         return -1;
      }
      publisher_state->device_state_filter = 1;
   }

   publisher_state->client = ao2_bump(client);

   if (ast_sip_publish_client_add_datastore(client, datastore)) {
      return -1;
   }

   publisher_state->device_state_subscription = stasis_subscribe(ast_device_state_topic_all(),
      asterisk_publisher_devstate_cb, ao2_bump(datastore));
   if (!publisher_state->device_state_subscription) {
      ast_sip_publish_client_remove_datastore(client, "asterisk-devicestate-publisher");
      ao2_ref(datastore, -1);
      return -1;
   }
   stasis_subscription_accept_message_type(publisher_state->device_state_subscription, ast_device_state_message_type());
   stasis_subscription_accept_message_type(publisher_state->device_state_subscription, stasis_subscription_change_type());
   stasis_subscription_set_filter(publisher_state->device_state_subscription, STASIS_SUBSCRIPTION_FILTER_SELECTIVE);

   cached = stasis_cache_dump(ast_device_state_cache(), NULL);
   ao2_callback(cached, OBJ_NODATA, cached_devstate_cb, datastore);
   ao2_ref(cached, -1);

   return 0;
}

static int asterisk_stop_devicestate_publishing(struct ast_sip_outbound_publish_client *client)
{
   RAII_VAR(struct ast_datastore *, datastore, ast_sip_publish_client_get_datastore(client, "asterisk-devicestate-publisher"),
      ao2_cleanup);
   struct asterisk_devicestate_publisher_state *publisher_state;

   if (!datastore) {
      return 0;
   }

   publisher_state = datastore->data;
   if (publisher_state->device_state_subscription) {
      stasis_unsubscribe_and_join(publisher_state->device_state_subscription);
      ao2_ref(datastore, -1);
   }

   ast_sip_publish_client_remove_datastore(client, "asterisk-devicestate-publisher");

   return 0;
}

struct ast_sip_event_publisher_handler asterisk_devicestate_publisher_handler = {
   .event_name = "asterisk-devicestate",
   .start_publishing = asterisk_start_devicestate_publishing,
   .stop_publishing = asterisk_stop_devicestate_publishing,
};

static int asterisk_start_mwi_publishing(struct ast_sip_outbound_publish *configuration,
   struct ast_sip_outbound_publish_client *client)
{
   RAII_VAR(struct ast_datastore *, datastore, NULL, ao2_cleanup);
   struct asterisk_mwi_publisher_state *publisher_state;
   const char *value;
   struct ao2_container *cached;

   datastore = ast_sip_publish_client_alloc_datastore(&asterisk_mwi_publisher_state_datastore, "asterisk-mwi-publisher");
   if (!datastore) {
      return -1;
   }

   publisher_state = ast_calloc(1, sizeof(struct asterisk_mwi_publisher_state));
   if (!publisher_state) {
      return -1;
   }
   datastore->data = publisher_state;

   value = ast_sorcery_object_get_extended(configuration, "mailbox_state_filter");
   if (!ast_strlen_zero(value)) {
      if (build_regex(&publisher_state->mailbox_state_regex, value)) {
         return -1;
      }
      publisher_state->mailbox_state_filter = 1;
   }

   publisher_state->client = ao2_bump(client);

   if (ast_sip_publish_client_add_datastore(client, datastore)) {
      return -1;
   }

   publisher_state->mailbox_state_subscription = stasis_subscribe(ast_mwi_topic_all(),
      asterisk_publisher_mwistate_cb, ao2_bump(datastore));
   if (!publisher_state->mailbox_state_subscription) {
      ast_sip_publish_client_remove_datastore(client, "asterisk-mwi-publisher");
      ao2_ref(datastore, -1);
      return -1;
   }
   stasis_subscription_accept_message_type(publisher_state->mailbox_state_subscription, ast_mwi_state_type());
   stasis_subscription_accept_message_type(publisher_state->mailbox_state_subscription, stasis_subscription_change_type());
   stasis_subscription_set_filter(publisher_state->mailbox_state_subscription, STASIS_SUBSCRIPTION_FILTER_SELECTIVE);

   cached = stasis_cache_dump(ast_mwi_state_cache(), NULL);
   ao2_callback(cached, OBJ_NODATA, cached_mwistate_cb, datastore);
   ao2_ref(cached, -1);

   return 0;
}

static int asterisk_stop_mwi_publishing(struct ast_sip_outbound_publish_client *client)
{
   RAII_VAR(struct ast_datastore *, datastore, ast_sip_publish_client_get_datastore(client, "asterisk-mwi-publisher"),
      ao2_cleanup);
   struct asterisk_mwi_publisher_state *publisher_state;

   if (!datastore) {
      return 0;
   }

   publisher_state = datastore->data;
   if (publisher_state->mailbox_state_subscription) {
      stasis_unsubscribe_and_join(publisher_state->mailbox_state_subscription);
      ao2_ref(datastore, -1);
   }

   ast_sip_publish_client_remove_datastore(client, "asterisk-mwi-publisher");

   return 0;
}

struct ast_sip_event_publisher_handler asterisk_mwi_publisher_handler = {
   .event_name = "asterisk-mwi",
   .start_publishing = asterisk_start_mwi_publishing,
   .stop_publishing = asterisk_stop_mwi_publishing,
};

static int asterisk_publication_new(struct ast_sip_endpoint *endpoint, const char *resource, const char *event_configuration)
{
   RAII_VAR(struct asterisk_publication_config *, config, ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "asterisk-publication",
      event_configuration), ao2_cleanup);

   /* If no inbound Asterisk publication configuration exists reject the PUBLISH */
   if (!config) {
      return 404;
   }

   return 200;
}

static int asterisk_publication_devicestate(struct ast_sip_publication *pub, struct asterisk_publication_config *config,
   struct ast_eid *pubsub_eid, struct ast_json *json)
{
   const char *device = ast_json_string_get(ast_json_object_get(json, "device"));
   const char *state = ast_json_string_get(ast_json_object_get(json, "state"));
   int cachable = ast_json_integer_get(ast_json_object_get(json, "cachable"));

   if (!config->device_state) {
      ast_debug(2, "Received device state event for resource '%s' but it is not configured to accept them\n",
         ast_sorcery_object_get_id(config));
      return 0;
   }

   if (ast_strlen_zero(device) || ast_strlen_zero(state)) {
      ast_debug(1, "Received incomplete device state event for resource '%s'\n",
         ast_sorcery_object_get_id(config));
      return -1;
   }

   if (config->device_state_filter && regexec(&config->device_state_regex, device, 0, NULL, 0)) {
      ast_debug(2, "Received device state on resource '%s' for device '%s' but it has been filtered out\n",
         ast_sorcery_object_get_id(config), device);
      return 0;
   }

   ast_publish_device_state_full(device, ast_devstate_val(state),
      cachable == AST_DEVSTATE_CACHABLE ? AST_DEVSTATE_CACHABLE : AST_DEVSTATE_NOT_CACHABLE,
      pubsub_eid);

   return 0;
}

static int asterisk_publication_mailboxstate(struct ast_sip_publication *pub, struct asterisk_publication_config *config,
   struct ast_eid *pubsub_eid, struct ast_json *json)
{
   const char *uniqueid = ast_json_string_get(ast_json_object_get(json, "uniqueid"));
   int old_msgs = ast_json_integer_get(ast_json_object_get(json, "old"));
   int new_msgs = ast_json_integer_get(ast_json_object_get(json, "new"));
   char *item_id;
   const char *mailbox;

   if (!config->mailbox_state) {
      ast_debug(2, "Received mailbox state event for resource '%s' but it is not configured to accept them\n",
         ast_sorcery_object_get_id(config));
      return 0;
   }

   if (ast_strlen_zero(uniqueid)) {
      ast_debug(1, "Received incomplete mailbox state event for resource '%s'\n",
         ast_sorcery_object_get_id(config));
      return -1;
   }

   if (config->mailbox_state_filter && regexec(&config->mailbox_state_regex, uniqueid, 0, NULL, 0)) {
      ast_debug(2, "Received mailbox state on resource '%s' for uniqueid '%s' but it has been filtered out\n",
         ast_sorcery_object_get_id(config), uniqueid);
      return 0;
   }

   item_id = ast_strdupa(uniqueid);
   mailbox = strsep(&item_id, "@");

   ast_publish_mwi_state_full(mailbox, item_id, new_msgs, old_msgs, NULL, pubsub_eid);

   return 0;
}

static int asterisk_publication_devicestate_refresh(struct ast_sip_publication *pub,
   struct asterisk_publication_config *config, struct ast_eid *pubsub_eid, struct ast_json *json)
{
   struct ast_sip_outbound_publish_client *client;
   struct ast_datastore *datastore;
   struct ao2_container *cached;

   if (ast_strlen_zero(config->devicestate_publish)) {
      return 0;
   }

   client = ast_sip_publish_client_get(config->devicestate_publish);
   if (!client) {
      ast_log(LOG_ERROR, "Received refresh request for devicestate on publication '%s' but publish '%s' is not available\n",
         ast_sorcery_object_get_id(config), config->devicestate_publish);
      return 0;
   }

   datastore = ast_sip_publish_client_get_datastore(client, "asterisk-devicestate-publisher");
   if (!datastore) {
      ao2_ref(client, -1);
      return 0;
   }

   cached = stasis_cache_dump(ast_device_state_cache(), NULL);
   if (cached) {
      ao2_callback(cached, OBJ_NODATA, cached_devstate_cb, datastore);
      ao2_ref(cached, -1);
   }
   ao2_ref(client, -1);
   ao2_ref(datastore, -1);

   return 0;
}

static int asterisk_publication_devicestate_state_change(struct ast_sip_publication *pub, pjsip_msg_body *body,
         enum ast_sip_publish_state state)
{
   RAII_VAR(struct asterisk_publication_config *, config, ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "asterisk-publication",
      ast_sip_publication_get_event_configuration(pub)), ao2_cleanup);
   RAII_VAR(struct ast_json *, json, NULL, ast_json_unref);
   const char *eid, *type;
   struct ast_eid pubsub_eid;
   int res = -1;

   /* If no configuration exists for this publication it has most likely been removed, so drop this immediately */
   if (!config) {
      return -1;
   }

   /* If no body exists this is a refresh and can be ignored */
   if (!body) {
      return 0;
   }

   /* We only accept JSON for content */
   if (!ast_sip_is_content_type(&body->content_type, "application", "json")) {
      ast_debug(2, "Received unsupported content type for Asterisk event on resource '%s'\n",
         ast_sorcery_object_get_id(config));
      return -1;
   }

   json = ast_json_load_buf(body->data, body->len, NULL);
   if (!json) {
      ast_debug(1, "Received unparseable JSON event for resource '%s'\n",
         ast_sorcery_object_get_id(config));
      return -1;
   }

   eid = ast_json_string_get(ast_json_object_get(json, "eid"));
   if (!eid) {
      ast_debug(1, "Received event without eid for resource '%s'\n",
         ast_sorcery_object_get_id(config));
      return -1;
   }
   ast_str_to_eid(&pubsub_eid, eid);

   type = ast_json_string_get(ast_json_object_get(json, "type"));
   if (!type) {
      ast_debug(1, "Received event without type for resource '%s'\n",
         ast_sorcery_object_get_id(config));
      return -1;
   } else if (!strcmp(type, "devicestate")) {
      res = asterisk_publication_devicestate(pub, config, &pubsub_eid, json);
   } else if (!strcmp(type, "refresh")) {
      res = asterisk_publication_devicestate_refresh(pub, config, &pubsub_eid, json);
   }

   return res;
}

static int asterisk_publication_mwi_refresh(struct ast_sip_publication *pub,
   struct asterisk_publication_config *config, struct ast_eid *pubsub_eid, struct ast_json *json)
{
   struct ast_sip_outbound_publish_client *client;
   struct ast_datastore *datastore;
   struct ao2_container *cached;

   if (ast_strlen_zero(config->mailboxstate_publish)) {
      return 0;
   }

   client = ast_sip_publish_client_get(config->mailboxstate_publish);
   if (!client) {
      ast_log(LOG_ERROR, "Received refresh request for mwi state on publication '%s' but publish '%s' is not available\n",
         ast_sorcery_object_get_id(config), config->mailboxstate_publish);
      return 0;
   }

   datastore = ast_sip_publish_client_get_datastore(client, "asterisk-mwi-publisher");
   if (!datastore) {
      ao2_ref(client, -1);
      return 0;
   }

   cached = stasis_cache_dump(ast_mwi_state_cache(), NULL);
   if (cached) {
      ao2_callback(cached, OBJ_NODATA, cached_mwistate_cb, datastore);
      ao2_ref(cached, -1);
   }
   ao2_ref(client, -1);
   ao2_ref(datastore, -1);

   return 0;
}

static int asterisk_publication_mwi_state_change(struct ast_sip_publication *pub, pjsip_msg_body *body,
         enum ast_sip_publish_state state)
{
   RAII_VAR(struct asterisk_publication_config *, config, ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "asterisk-publication",
      ast_sip_publication_get_event_configuration(pub)), ao2_cleanup);
   RAII_VAR(struct ast_json *, json, NULL, ast_json_unref);
   const char *eid, *type;
   struct ast_eid pubsub_eid;
   int res = -1;

   /* If no configuration exists for this publication it has most likely been removed, so drop this immediately */
   if (!config) {
      return -1;
   }

   /* If no body exists this is a refresh and can be ignored */
   if (!body) {
      return 0;
   }

   /* We only accept JSON for content */
   if (!ast_sip_is_content_type(&body->content_type, "application", "json")) {
      ast_debug(2, "Received unsupported content type for Asterisk event on resource '%s'\n",
         ast_sorcery_object_get_id(config));
      return -1;
   }

   json = ast_json_load_buf(body->data, body->len, NULL);
   if (!json) {
      ast_debug(1, "Received unparseable JSON event for resource '%s'\n",
         ast_sorcery_object_get_id(config));
      return -1;
   }

   eid = ast_json_string_get(ast_json_object_get(json, "eid"));
   if (!eid) {
      ast_debug(1, "Received event without eid for resource '%s'\n",
         ast_sorcery_object_get_id(config));
      return -1;
   }
   ast_str_to_eid(&pubsub_eid, eid);

   type = ast_json_string_get(ast_json_object_get(json, "type"));
   if (!type) {
      ast_debug(1, "Received event without type for resource '%s'\n",
         ast_sorcery_object_get_id(config));
      return -1;
   } else if (!strcmp(type, "mailboxstate")) {
      res = asterisk_publication_mailboxstate(pub, config, &pubsub_eid, json);
   } else if (!strcmp(type, "refresh")) {
      res = asterisk_publication_mwi_refresh(pub, config, &pubsub_eid, json);
   }

   return res;
}

static int send_refresh_cb(void *obj, void *arg, int flags)
{
   struct asterisk_publication_config *config = obj;
   struct ast_sip_outbound_publish_client *client;

   if (!ast_strlen_zero(config->devicestate_publish)) {
      client = ast_sip_publish_client_get(config->devicestate_publish);
      if (client) {
         ast_sip_publish_client_send(client, arg);
         ao2_ref(client, -1);
      }
   }

   if (!ast_strlen_zero(config->mailboxstate_publish)) {
      client = ast_sip_publish_client_get(config->mailboxstate_publish);
      if (client) {
         ast_sip_publish_client_send(client, arg);
         ao2_ref(client, -1);
      }
   }

   return 0;
}

/*! \brief Internal function to send refresh requests to all publications */
static void asterisk_publication_send_refresh(void)
{
   struct ao2_container *publications = ast_sorcery_retrieve_by_fields(ast_sip_get_sorcery(), "asterisk-publication", AST_RETRIEVE_FLAG_MULTIPLE | AST_RETRIEVE_FLAG_ALL, NULL);
   char eid_str[20];
   struct ast_json *json;
   char *text;
   struct ast_sip_body body = {
      .type = "application",
      .subtype = "json",
   };

   if (!publications) {
      return;
   }

   ast_eid_to_str(eid_str, sizeof(eid_str), &ast_eid_default);
   json = ast_json_pack(
      "{ s: s, s: s }",
      "type", "refresh",
      "eid", eid_str);
   if (!json) {
      ao2_ref(publications, -1);
      return;
   }

   text = ast_json_dump_string(json);
   if (!text) {
      ast_json_unref(json);
      ao2_ref(publications, -1);
      return;
   }
   body.body_text = text;

   ao2_callback(publications, OBJ_NODATA, send_refresh_cb, &body);

   ast_json_free(text);
   ast_json_unref(json);
   ao2_ref(publications, -1);
}

struct ast_sip_publish_handler asterisk_devicestate_publication_handler = {
   .event_name = "asterisk-devicestate",
   .new_publication = asterisk_publication_new,
   .publication_state_change = asterisk_publication_devicestate_state_change,
};

struct ast_sip_publish_handler asterisk_mwi_publication_handler = {
   .event_name = "asterisk-mwi",
   .new_publication = asterisk_publication_new,
   .publication_state_change = asterisk_publication_mwi_state_change,
};

/*! \brief Destructor function for Asterisk publication configuration */
static void asterisk_publication_config_destroy(void *obj)
{
   struct asterisk_publication_config *config = obj;

   ast_string_field_free_memory(config);
}

/*! \brief Allocator function for Asterisk publication configuration */
static void *asterisk_publication_config_alloc(const char *name)
{
   struct asterisk_publication_config *config = ast_sorcery_generic_alloc(sizeof(*config),
      asterisk_publication_config_destroy);

   if (!config || ast_string_field_init(config, 256)) {
      ao2_cleanup(config);
      return NULL;
   }

   return config;
}

static int regex_filter_handler(const struct aco_option *opt, struct ast_variable *var, void *obj)
{
   struct asterisk_publication_config *config = obj;
   int res = -1;

   if (ast_strlen_zero(var->value)) {
      return 0;
   }

   if (!strcmp(var->name, "device_state_filter")) {
      if (!(res = build_regex(&config->device_state_regex, var->value))) {
         config->device_state_filter = 1;
      }
   } else if (!strcmp(var->name, "mailbox_state_filter")) {
      if (!(res = build_regex(&config->mailbox_state_regex, var->value))) {
         config->mailbox_state_filter = 1;
      }
   }

   return res;
}

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

   ast_sorcery_apply_config(ast_sip_get_sorcery(), "res_pjsip_publish_asterisk");
   ast_sorcery_apply_default(ast_sip_get_sorcery(), "asterisk-publication", "config", "pjsip.conf,criteria=type=asterisk-publication");

   if (ast_sorcery_object_register(ast_sip_get_sorcery(), "asterisk-publication", asterisk_publication_config_alloc, NULL, NULL)) {
      ast_log(LOG_ERROR, "Unable to register 'asterisk-publication' type with sorcery\n");
      return AST_MODULE_LOAD_DECLINE;
   }

   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "asterisk-publication", "type", "", OPT_NOOP_T, 0, 0);
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "asterisk-publication", "devicestate_publish", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct asterisk_publication_config, devicestate_publish));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "asterisk-publication", "mailboxstate_publish", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct asterisk_publication_config, mailboxstate_publish));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "asterisk-publication", "device_state", "no", OPT_BOOL_T, 1, FLDSET(struct asterisk_publication_config, device_state));
   ast_sorcery_object_field_register_custom(ast_sip_get_sorcery(), "asterisk-publication", "device_state_filter", "", regex_filter_handler, NULL, NULL, 0, 0);
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "asterisk-publication", "mailbox_state", "no", OPT_BOOL_T, 1, FLDSET(struct asterisk_publication_config, mailbox_state));
   ast_sorcery_object_field_register_custom(ast_sip_get_sorcery(), "asterisk-publication", "mailbox_state_filter", "", regex_filter_handler, NULL, NULL, 0, 0);
   ast_sorcery_reload_object(ast_sip_get_sorcery(), "asterisk-publication");

   if (ast_sip_register_publish_handler(&asterisk_devicestate_publication_handler)) {
      ast_log(LOG_WARNING, "Unable to register event publication handler %s\n",
         asterisk_devicestate_publication_handler.event_name);
      return AST_MODULE_LOAD_DECLINE;
   }
   if (ast_sip_register_publish_handler(&asterisk_mwi_publication_handler)) {
      ast_log(LOG_WARNING, "Unable to register event publication handler %s\n",
         asterisk_mwi_publication_handler.event_name);
      ast_sip_unregister_publish_handler(&asterisk_devicestate_publication_handler);
      return AST_MODULE_LOAD_DECLINE;
   }
   if (ast_sip_register_event_publisher_handler(&asterisk_devicestate_publisher_handler)) {
      ast_log(LOG_WARNING, "Unable to register event publisher handler %s\n",
         asterisk_devicestate_publisher_handler.event_name);
      ast_sip_unregister_publish_handler(&asterisk_devicestate_publication_handler);
      ast_sip_unregister_publish_handler(&asterisk_mwi_publication_handler);
      return AST_MODULE_LOAD_DECLINE;
   }
   if (ast_sip_register_event_publisher_handler(&asterisk_mwi_publisher_handler)) {
      ast_log(LOG_WARNING, "Unable to register event publisher handler %s\n",
         asterisk_mwi_publisher_handler.event_name);
      ast_sip_unregister_event_publisher_handler(&asterisk_mwi_publisher_handler);
      ast_sip_unregister_publish_handler(&asterisk_devicestate_publication_handler);
      ast_sip_unregister_publish_handler(&asterisk_mwi_publication_handler);
      return AST_MODULE_LOAD_DECLINE;
   }

   asterisk_publication_send_refresh();

   return AST_MODULE_LOAD_SUCCESS;
}

static int reload_module(void)
{
   ast_sorcery_reload_object(ast_sip_get_sorcery(), "asterisk-publication");
   asterisk_publication_send_refresh();
   return 0;
}

static int unload_module(void)
{
   ast_sip_unregister_publish_handler(&asterisk_devicestate_publication_handler);
   ast_sip_unregister_publish_handler(&asterisk_mwi_publication_handler);
   ast_sip_unregister_event_publisher_handler(&asterisk_devicestate_publisher_handler);
   ast_sip_unregister_event_publisher_handler(&asterisk_mwi_publisher_handler);
   ast_sorcery_object_unregister(ast_sip_get_sorcery(), "asterisk-publication");
   return 0;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Asterisk Event PUBLISH Support",
   .support_level = AST_MODULE_SUPPORT_CORE,
   .load = load_module,
   .reload = reload_module,
   .unload = unload_module,
   .load_pri = AST_MODPRI_CHANNEL_DEPEND + 5,
   .requires = "res_pjsip,res_pjsip_outbound_publish,res_pjsip_pubsub",
);