bridge_roles.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * Jonathan Rose <[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
 *
 * \brief Channel Bridging Roles API
 *
 * \author Jonathan Rose <[email protected]>
 *
 * \ingroup bridges
 */

/*** MODULEINFO
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include <signal.h>

#include "asterisk/logger.h"
#include "asterisk/channel.h"
#include "asterisk/datastore.h"
#include "asterisk/linkedlists.h"
#include "asterisk/bridge.h"
#include "asterisk/bridge_roles.h"
#include "asterisk/stringfields.h"

struct bridge_role_option {
   AST_LIST_ENTRY(bridge_role_option) list;
   AST_DECLARE_STRING_FIELDS(
      AST_STRING_FIELD(option);
      AST_STRING_FIELD(value);
   );
};

struct bridge_role {
   AST_LIST_ENTRY(bridge_role) list;
   AST_LIST_HEAD_NOLOCK(, bridge_role_option) options;
   char role[AST_ROLE_LEN];
};

struct bridge_roles_datastore {
   AST_LIST_HEAD_NOLOCK(, bridge_role) role_list;
};

/*!
 * \internal
 * \brief Destructor function for a bridge role
 * \since 12.0.0
 *
 * \param role bridge_role being destroyed
 *
 * \return Nothing
 */
static void bridge_role_destroy(struct bridge_role *role)
{
   struct bridge_role_option *role_option;
   while ((role_option = AST_LIST_REMOVE_HEAD(&role->options, list))) {
      ast_string_field_free_memory(role_option);
      ast_free(role_option);
   }
   ast_free(role);
}

/*!
 * \internal
 * \brief Destructor function for bridge role datastores
 * \since 12.0.0
 *
 * \param data Pointer to the datastore being destroyed
 *
 * \return Nothing
 */
static void bridge_role_datastore_destroy(void *data)
{
   struct bridge_roles_datastore *roles_datastore = data;
   struct bridge_role *role;

   while ((role = AST_LIST_REMOVE_HEAD(&roles_datastore->role_list, list))) {
      bridge_role_destroy(role);
   }

   ast_free(roles_datastore);
}

static const struct ast_datastore_info bridge_role_info = {
   .type = "bridge roles",
   .destroy = bridge_role_datastore_destroy,
};

/*!
 * \internal
 * \brief Setup a bridge role datastore on a channel
 * \since 12.0.0
 *
 * \param chan Chan the datastore is being setup on
 *
 * \retval NULL if failed
 * \retval pointer to the newly created datastore
 */
static struct bridge_roles_datastore *setup_bridge_roles_datastore(struct ast_channel *chan)
{
   struct ast_datastore *datastore = NULL;
   struct bridge_roles_datastore *roles_datastore = NULL;

   if (!(datastore = ast_datastore_alloc(&bridge_role_info, NULL))) {
      return NULL;
   }

   if (!(roles_datastore = ast_calloc(1, sizeof(*roles_datastore)))) {
      ast_datastore_free(datastore);
      return NULL;
   }

   AST_LIST_HEAD_INIT_NOLOCK(&roles_datastore->role_list);

   datastore->data = roles_datastore;
   ast_channel_datastore_add(chan, datastore);
   return roles_datastore;
}

/*!
 * \internal
 * \brief Get the bridge_roles_datastore from a channel if it exists. Don't create one if it doesn't.
 * \since 12.0.0
 *
 * \param chan Channel we want the bridge_roles_datastore from
 *
 * \retval NULL if we can't find the datastore
 * \retval pointer to the bridge_roles_datastore
 */
static struct bridge_roles_datastore *fetch_bridge_roles_datastore(struct ast_channel *chan)
{
   struct ast_datastore *datastore = NULL;

   ast_channel_lock(chan);
   if (!(datastore = ast_channel_datastore_find(chan, &bridge_role_info, NULL))) {
      ast_channel_unlock(chan);
      return NULL;
   }
   ast_channel_unlock(chan);

   return datastore->data;
}

/*!
 * \internal
 * \brief Get the bridge_roles_datastore from a channel if it exists. If not, create one.
 * \since 12.0.0
 *
 * \param chan Channel we want the bridge_roles_datastore from
 *
 * \retval NULL If we can't find and can't create the datastore
 * \retval pointer to the bridge_roles_datastore
 */
static struct bridge_roles_datastore *fetch_or_create_bridge_roles_datastore(struct ast_channel *chan)
{
   struct bridge_roles_datastore *roles_datastore;

   ast_channel_lock(chan);
   roles_datastore = fetch_bridge_roles_datastore(chan);
   if (!roles_datastore) {
      roles_datastore = setup_bridge_roles_datastore(chan);
   }
   ast_channel_unlock(chan);

   return roles_datastore;
}

/*!
 * \internal
 * \brief Obtain a role from a bridge_roles_datastore if the datastore has it
 * \since 12.0.0
 *
 * \param roles_datastore The bridge_roles_datastore we are looking for the role of
 * \param role_name Name of the role being sought
 *
 * \retval NULL if the datastore does not have the requested role
 * \retval pointer to the requested role
 */
static struct bridge_role *get_role_from_datastore(struct bridge_roles_datastore *roles_datastore, const char *role_name)
{
   struct bridge_role *role;

   AST_LIST_TRAVERSE(&roles_datastore->role_list, role, list) {
      if (!strcmp(role->role, role_name)) {
         return role;
      }
   }

   return NULL;
}

/*!
 * \internal
 * \brief Obtain a role from a channel structure if the channel's datastore has it
 * \since 12.0.0
 *
 * \param channel The channel we are checking the role of
 * \param role_name Name of the role sought
 *
 * \retval NULL if the channel's datastore does not have the requested role
 * \retval pointer to the requested role
 */
static struct bridge_role *get_role_from_channel(struct ast_channel *channel, const char *role_name)
{
   struct bridge_roles_datastore *roles_datastore = fetch_bridge_roles_datastore(channel);
   return roles_datastore ? get_role_from_datastore(roles_datastore, role_name) : NULL;
}

/*!
 * \internal
 * \brief Obtain a role option from a bridge role if it exists in the bridge role's option list
 * \since 12.0.0
 *
 * \param role a pointer to the bridge role wea re searching for the option of
 * \param option Name of the option sought
 *
 * \retval NULL if the bridge role doesn't have the requested option
 * \retval pointer to the requested option
 */
static struct bridge_role_option *get_role_option(struct bridge_role *role, const char *option)
{
   struct bridge_role_option *role_option = NULL;
   AST_LIST_TRAVERSE(&role->options, role_option, list) {
      if (!strcmp(role_option->option, option)) {
         return role_option;
      }
   }
   return NULL;
}

/*!
 * \internal
 * \brief Setup a bridge role on an existing bridge role datastore
 * \since 12.0.0
 *
 * \param roles_datastore bridge_roles_datastore receiving the new role
 * \param role_name Name of the role being received
 *
 * \retval 0 on success
 * \retval -1 on failure
 */
static int setup_bridge_role(struct bridge_roles_datastore *roles_datastore, const char *role_name)
{
   struct bridge_role *role;
   role = ast_calloc(1, sizeof(*role));

   if (!role) {
      return -1;
   }

   AST_LIST_HEAD_INIT_NOLOCK(&role->options);

   ast_copy_string(role->role, role_name, sizeof(role->role));

   AST_LIST_INSERT_TAIL(&roles_datastore->role_list, role, list);
   ast_debug(3, "Set role '%s'\n", role_name);

   return 0;
}

/*!
 * \internal
 * \brief Setup a bridge role option on an existing bridge role
 * \since 12.0.0
 *
 * \param role The role receiving the option
 * \param option Name of the option
 * \param value the option's value
 *
 * \retval 0 on success
 * \retval -1 on failure
 */
static int setup_bridge_role_option(struct bridge_role *role, const char *option, const char *value)
{
   struct bridge_role_option *role_option;

   if (!value) {
      value = "";
   }

   role_option = ast_calloc(1, sizeof(*role_option));
   if (!role_option) {
      return -1;
   }

   if (ast_string_field_init(role_option, 32)) {
      ast_free(role_option);
      return -1;
   }

   ast_string_field_set(role_option, option, option);
   ast_string_field_set(role_option, value, value);

   AST_LIST_INSERT_TAIL(&role->options, role_option, list);

   return 0;
}

int ast_channel_add_bridge_role(struct ast_channel *chan, const char *role_name)
{
   struct bridge_roles_datastore *roles_datastore = fetch_or_create_bridge_roles_datastore(chan);

   if (!roles_datastore) {
      ast_log(LOG_WARNING, "Unable to set up bridge role datastore on channel %s\n", ast_channel_name(chan));
      return -1;
   }

   /* Check to make sure we aren't adding a redundant role */
   if (get_role_from_datastore(roles_datastore, role_name)) {
      ast_debug(2, "Bridge role %s is already applied to the channel %s\n", role_name, ast_channel_name(chan));
      return 0;
   }

   /* It wasn't already there, so we can just finish setting it up now. */
   return setup_bridge_role(roles_datastore, role_name);
}

void ast_channel_remove_bridge_role(struct ast_channel *chan, const char *role_name)
{
   struct bridge_roles_datastore *roles_datastore = fetch_bridge_roles_datastore(chan);
   struct bridge_role *role;

   if (!roles_datastore) {
      /* The roles datastore didn't already exist, so there is no need to remove a role */
      ast_debug(2, "Role %s did not exist on channel %s\n", role_name, ast_channel_name(chan));
      return;
   }

   AST_LIST_TRAVERSE_SAFE_BEGIN(&roles_datastore->role_list, role, list) {
      if (!strcmp(role->role, role_name)) {
         ast_debug(2, "Removing bridge role %s from channel %s\n", role_name, ast_channel_name(chan));
         AST_LIST_REMOVE_CURRENT(list);
         bridge_role_destroy(role);
         return;
      }
   }
   AST_LIST_TRAVERSE_SAFE_END;

   ast_debug(2, "Role %s did not exist on channel %s\n", role_name, ast_channel_name(chan));
}

void ast_channel_clear_bridge_roles(struct ast_channel *chan)
{
   struct bridge_roles_datastore *roles_datastore = fetch_bridge_roles_datastore(chan);
   struct bridge_role *role;

   if (!roles_datastore) {
      /* The roles datastore didn't already exist, so there is no need to remove any roles */
      ast_debug(2, "Roles did not exist on channel %s\n", ast_channel_name(chan));
      return;
   }

   AST_LIST_TRAVERSE_SAFE_BEGIN(&roles_datastore->role_list, role, list) {
      ast_debug(2, "Removing bridge role %s from channel %s\n", role->role, ast_channel_name(chan));
      AST_LIST_REMOVE_CURRENT(list);
      bridge_role_destroy(role);
   }
   AST_LIST_TRAVERSE_SAFE_END;
}

int ast_channel_set_bridge_role_option(struct ast_channel *channel, const char *role_name, const char *option, const char *value)
{
   struct bridge_role *role = get_role_from_channel(channel, role_name);
   struct bridge_role_option *role_option;

   if (!role) {
      return -1;
   }

   role_option = get_role_option(role, option);

   if (role_option) {
      ast_string_field_set(role_option, value, value);
      return 0;
   }

   return setup_bridge_role_option(role, option, value);
}

int ast_channel_has_role(struct ast_channel *channel, const char *role_name)
{
   return get_role_from_channel(channel, role_name) ? 1 : 0;
}

const char *ast_channel_get_role_option(struct ast_channel *channel, const char *role_name, const char *option)
{
   struct bridge_role *role;
   struct bridge_role_option *role_option;

   role = get_role_from_channel(channel, role_name);
   if (!role) {
      return NULL;
   }

   role_option = get_role_option(role, option);

   return role_option ? role_option->value : NULL;
}

int ast_bridge_channel_has_role(struct ast_bridge_channel *bridge_channel, const char *role_name)
{
   if (!bridge_channel->bridge_roles) {
      return 0;
   }

   return get_role_from_datastore(bridge_channel->bridge_roles, role_name) ? 1 : 0;
}

const char *ast_bridge_channel_get_role_option(struct ast_bridge_channel *bridge_channel, const char *role_name, const char *option)
{
   struct bridge_role *role;
   struct bridge_role_option *role_option = NULL;

   if (!bridge_channel->bridge_roles) {
      return NULL;
   }

   role = get_role_from_datastore(bridge_channel->bridge_roles, role_name);

   if (!role) {
      return NULL;
   }

   role_option = get_role_option(role, option);

   return role_option ? role_option->value : NULL;
}

int ast_bridge_channel_establish_roles(struct ast_bridge_channel *bridge_channel)
{
   struct bridge_roles_datastore *roles_datastore;
   struct bridge_role *role = NULL;
   struct bridge_role_option *role_option;

   if (!bridge_channel->chan) {
      ast_debug(2, "Attempted to set roles on a bridge channel that has no associated channel. That's a bad idea.\n");
      return -1;
   }

   if (bridge_channel->bridge_roles) {
      ast_debug(2, "Attempted to reset roles while roles were already established. Purge existing roles first.\n");
      return -1;
   }

   roles_datastore = fetch_bridge_roles_datastore(bridge_channel->chan);
   if (!roles_datastore) {
      /* No roles to establish. */
      return 0;
   }

   if (!(bridge_channel->bridge_roles = ast_calloc(1, sizeof(*bridge_channel->bridge_roles)))) {
      return -1;
   }

   AST_LIST_TRAVERSE(&roles_datastore->role_list, role, list) {
      struct bridge_role *this_role_copy;

      if (setup_bridge_role(bridge_channel->bridge_roles, role->role)) {
         /* We need to abandon the copy because we couldn't setup a role */
         ast_bridge_channel_clear_roles(bridge_channel);
         return -1;
      }
      this_role_copy = AST_LIST_LAST(&bridge_channel->bridge_roles->role_list);

      AST_LIST_TRAVERSE(&role->options, role_option, list) {
         if (setup_bridge_role_option(this_role_copy, role_option->option, role_option->value)) {
            /* We need to abandon the copy because we couldn't setup a role option */
            ast_bridge_channel_clear_roles(bridge_channel);
            return -1;
         }
      }
   }

   return 0;
}

void ast_bridge_channel_clear_roles(struct ast_bridge_channel *bridge_channel)
{
   if (bridge_channel->bridge_roles) {
      bridge_role_datastore_destroy(bridge_channel->bridge_roles);
      bridge_channel->bridge_roles = NULL;
   }
}