bridge_roles.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * Jonathan Rose <jrose@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
/*! \file
 *
 * \brief Channel Bridging Roles API
 *
 * \author Jonathan Rose <jrose@digium.com>
 *
 * \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
 */
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
 */
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
 * \return 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
 * \return 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
 * \return 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
 * \return 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
 * \return 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
 * \return 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;
    }
}