main/endpoints.c

Go to the documentation of this file.

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * David M. Lee, II <[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 Asterisk endpoint API.
 *
 * \author David M. Lee, II <[email protected]>
 */

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

#include "asterisk.h"

#include "asterisk/astobj2.h"
#include "asterisk/endpoints.h"
#include "asterisk/stasis.h"
#include "asterisk/stasis_channels.h"
#include "asterisk/stasis_endpoints.h"
#include "asterisk/stasis_message_router.h"
#include "asterisk/stringfields.h"
#include "asterisk/_private.h"

/*! Buckets for endpoint->channel mappings. Keep it prime! */
#define ENDPOINT_CHANNEL_BUCKETS 127

/*! Buckets for endpoint hash. Keep it prime! */
#define ENDPOINT_BUCKETS 127

/*! Buckets for technology endpoints. */
#define TECH_ENDPOINT_BUCKETS 11

static struct ao2_container *endpoints;

static struct ao2_container *tech_endpoints;

struct ast_endpoint {
 AST_DECLARE_STRING_FIELDS(
 AST_STRING_FIELD(tech); /*!< Technology (SIP, IAX2, etc.). */
 AST_STRING_FIELD(resource); /*!< Name, unique to the tech. */
 AST_STRING_FIELD(id); /*!< tech/resource id */
 );
 /*! Endpoint's current state */
 enum ast_endpoint_state state;
 /*!
 * \brief Max channels for this endpoint. -1 means unlimited or unknown.
 *
 * Note that this simply documents the limits of an endpoint, and does
 * nothing to try to enforce the limit.
 */
 int max_channels;
 /*! Topic for this endpoint's messages */
 struct stasis_cp_single *topics;
 /*! Router for handling this endpoint's messages */
 struct stasis_message_router *router;
 /*! ast_str_container of channels associated with this endpoint */
 struct ao2_container *channel_ids;
 /*! Forwarding subscription from an endpoint to its tech endpoint */
 struct stasis_forward *tech_forward;
};

AO2_STRING_FIELD_HASH_FN(ast_endpoint, id)
AO2_STRING_FIELD_CMP_FN(ast_endpoint, id)

struct ast_endpoint *ast_endpoint_find_by_id(const char *id)
{
 struct ast_endpoint *endpoint = ao2_find(endpoints, id, OBJ_KEY);

 if (!endpoint) {
 endpoint = ao2_find(tech_endpoints, id, OBJ_KEY);
 }

 return endpoint;
}

struct stasis_topic *ast_endpoint_topic(struct ast_endpoint *endpoint)
{
 if (!endpoint) {
 return ast_endpoint_topic_all();
 }
 return stasis_cp_single_topic(endpoint->topics);
}

struct stasis_topic *ast_endpoint_topic_cached(struct ast_endpoint *endpoint)
{
 if (!endpoint) {
 return ast_endpoint_topic_all_cached();
 }
 return stasis_cp_single_topic_cached(endpoint->topics);
}

const char *ast_endpoint_state_to_string(enum ast_endpoint_state state)
{
 switch (state) {
 case AST_ENDPOINT_UNKNOWN:
 return "unknown";
 case AST_ENDPOINT_OFFLINE:
 return "offline";
 case AST_ENDPOINT_ONLINE:
 return "online";
 }
 return "?";
}

static void endpoint_publish_snapshot(struct ast_endpoint *endpoint)
{
 RAII_VAR(struct ast_endpoint_snapshot *, snapshot, NULL, ao2_cleanup);
 RAII_VAR(struct stasis_message *, message, NULL, ao2_cleanup);

 ast_assert(endpoint != NULL);
 ast_assert(endpoint->topics != NULL);

 if (!ast_endpoint_snapshot_type()) {
 return;
 }

 snapshot = ast_endpoint_snapshot_create(endpoint);
 if (!snapshot) {
 return;
 }
 message = stasis_message_create(ast_endpoint_snapshot_type(), snapshot);
 if (!message) {
 return;
 }
 stasis_publish(ast_endpoint_topic(endpoint), message);
}

static void endpoint_dtor(void *obj)
{
 struct ast_endpoint *endpoint = obj;

 /* The router should be shut down already */
 ast_assert(stasis_message_router_is_done(endpoint->router));
 ao2_cleanup(endpoint->router);
 endpoint->router = NULL;

 stasis_cp_single_unsubscribe(endpoint->topics);
 endpoint->topics = NULL;

 ao2_cleanup(endpoint->channel_ids);
 endpoint->channel_ids = NULL;

 ast_string_field_free_memory(endpoint);
}


int ast_endpoint_add_channel(struct ast_endpoint *endpoint,
 struct ast_channel *chan)
{
 ast_assert(chan != NULL);
 ast_assert(endpoint != NULL);
 ast_assert(!ast_strlen_zero(endpoint->resource));

 ast_channel_forward_endpoint(chan, endpoint);

 ao2_lock(endpoint);
 ast_str_container_add(endpoint->channel_ids, ast_channel_uniqueid(chan));
 ao2_unlock(endpoint);

 endpoint_publish_snapshot(endpoint);

 return 0;
}

/*! \brief Handler for channel snapshot update */
static void endpoint_cache_clear(void *data,
 struct stasis_subscription *sub,
 struct stasis_message *message)
{
 struct ast_endpoint *endpoint = data;
 struct ast_channel_snapshot_update *update = stasis_message_data(message);

 /* Only when the channel is dead do we remove it */
 if (!ast_test_flag(&update->new_snapshot->flags, AST_FLAG_DEAD)) {
 return;
 }

 ast_assert(endpoint != NULL);

 ao2_lock(endpoint);
 ast_str_container_remove(endpoint->channel_ids, update->new_snapshot->base->uniqueid);
 ao2_unlock(endpoint);
 endpoint_publish_snapshot(endpoint);
}

static void endpoint_subscription_change(void *data,
 struct stasis_subscription *sub,
 struct stasis_message *message)
{
 struct stasis_endpoint *endpoint = data;

 if (stasis_subscription_final_message(sub, message)) {
 ao2_cleanup(endpoint);
 }
}

static struct ast_endpoint *endpoint_internal_create(const char *tech, const char *resource)
{
 RAII_VAR(struct ast_endpoint *, endpoint, NULL, ao2_cleanup);
 RAII_VAR(struct ast_endpoint *, tech_endpoint, NULL, ao2_cleanup);
 int r = 0;

 /* Get/create the technology endpoint */
 if (!ast_strlen_zero(resource)) {
 tech_endpoint = ao2_find(tech_endpoints, tech, OBJ_KEY);
 if (!tech_endpoint) {
 tech_endpoint = endpoint_internal_create(tech, NULL);
 if (!tech_endpoint) {
 return NULL;
 }
 }
 }

 endpoint = ao2_alloc(sizeof(*endpoint), endpoint_dtor);
 if (!endpoint) {
 return NULL;
 }

 endpoint->max_channels = -1;
 endpoint->state = AST_ENDPOINT_UNKNOWN;

 if (ast_string_field_init(endpoint, 80) != 0) {
 return NULL;
 }
 ast_string_field_set(endpoint, tech, tech);
 ast_string_field_set(endpoint, resource, S_OR(resource, ""));
 ast_string_field_build(endpoint, id, "%s%s%s",
 tech,
 !ast_strlen_zero(resource) ? "/" : "",
 S_OR(resource, ""));

 /* All access to channel_ids should be covered by the endpoint's
 * lock; no extra lock needed. */
 endpoint->channel_ids = ast_str_container_alloc_options(
 AO2_ALLOC_OPT_LOCK_NOLOCK, ENDPOINT_CHANNEL_BUCKETS);
 if (!endpoint->channel_ids) {
 return NULL;
 }

 if (!ast_strlen_zero(resource)) {
 char *topic_name;
 int ret;

 ret = ast_asprintf(&topic_name, "endpoint:%s", endpoint->id);
 if (ret < 0) {
 return NULL;
 }

 endpoint->topics = stasis_cp_single_create(ast_endpoint_cache_all(),
 topic_name);
 ast_free(topic_name);
 if (!endpoint->topics) {
 return NULL;
 }
 stasis_cp_single_accept_message_type(endpoint->topics, ast_endpoint_snapshot_type());
 stasis_cp_single_set_filter(endpoint->topics, STASIS_SUBSCRIPTION_FILTER_SELECTIVE);

 endpoint->router = stasis_message_router_create_pool(ast_endpoint_topic(endpoint));
 if (!endpoint->router) {
 return NULL;
 }
 r |= stasis_message_router_add(endpoint->router,
 ast_channel_snapshot_type(), endpoint_cache_clear,
 endpoint);
 r |= stasis_message_router_add(endpoint->router,
 stasis_subscription_change_type(), endpoint_subscription_change,
 endpoint);
 if (r) {
 return NULL;
 }

 endpoint->tech_forward = stasis_forward_all(stasis_cp_single_topic(endpoint->topics),
 stasis_cp_single_topic(tech_endpoint->topics));

 endpoint_publish_snapshot(endpoint);
 ao2_link(endpoints, endpoint);
 } else {
 char *topic_name;
 int ret;

 ret = ast_asprintf(&topic_name, "endpoint:%s", endpoint->id);
 if (ret < 0) {
 return NULL;
 }

 endpoint->topics = stasis_cp_sink_create(ast_endpoint_cache_all(),
 topic_name);
 ast_free(topic_name);
 if (!endpoint->topics) {
 return NULL;
 }
 stasis_cp_single_accept_message_type(endpoint->topics, ast_endpoint_snapshot_type());
 stasis_cp_single_set_filter(endpoint->topics, STASIS_SUBSCRIPTION_FILTER_SELECTIVE);

 ao2_link(tech_endpoints, endpoint);
 }

 ao2_ref(endpoint, +1);
 return endpoint;
}

struct ast_endpoint *ast_endpoint_create(const char *tech, const char *resource)
{
 if (ast_strlen_zero(tech)) {
 ast_log(LOG_ERROR, "Endpoint tech cannot be empty\n");
 return NULL;
 }

 if (ast_strlen_zero(resource)) {
 ast_log(LOG_ERROR, "Endpoint resource cannot be empty\n");
 return NULL;
 }

 return endpoint_internal_create(tech, resource);
}

static struct stasis_message *create_endpoint_snapshot_message(struct ast_endpoint *endpoint)
{
 RAII_VAR(struct ast_endpoint_snapshot *, snapshot, NULL, ao2_cleanup);

 if (!ast_endpoint_snapshot_type()) {
 return NULL;
 }

 snapshot = ast_endpoint_snapshot_create(endpoint);
 if (!snapshot) {
 return NULL;
 }

 return stasis_message_create(ast_endpoint_snapshot_type(), snapshot);
}

void ast_endpoint_shutdown(struct ast_endpoint *endpoint)
{
 RAII_VAR(struct stasis_message *, clear_msg, NULL, ao2_cleanup);

 if (endpoint == NULL) {
 return;
 }

 ao2_unlink(endpoints, endpoint);
 endpoint->tech_forward = stasis_forward_cancel(endpoint->tech_forward);

 clear_msg = create_endpoint_snapshot_message(endpoint);
 if (clear_msg) {
 RAII_VAR(struct stasis_message *, message, NULL, ao2_cleanup);
 message = stasis_cache_clear_create(clear_msg);
 if (message) {
 stasis_publish(ast_endpoint_topic(endpoint), message);
 }
 }

 /* Bump refcount to hold on to the router */
 ao2_ref(endpoint->router, +1);
 stasis_message_router_unsubscribe(endpoint->router);
}

const char *ast_endpoint_get_tech(const struct ast_endpoint *endpoint)
{
 if (!endpoint) {
 return NULL;
 }
 return endpoint->tech;
}

const char *ast_endpoint_get_resource(const struct ast_endpoint *endpoint)
{
 if (!endpoint) {
 return NULL;
 }
 return endpoint->resource;
}

const char *ast_endpoint_get_id(const struct ast_endpoint *endpoint)
{
 if (!endpoint) {
 return NULL;
 }
 return endpoint->id;
}

enum ast_endpoint_state ast_endpoint_get_state(const struct ast_endpoint *endpoint)
{
 if (!endpoint) {
 return AST_ENDPOINT_UNKNOWN;
 }
 return endpoint->state;
}

void ast_endpoint_set_state(struct ast_endpoint *endpoint,
 enum ast_endpoint_state state)
{
 ast_assert(endpoint != NULL);
 ast_assert(!ast_strlen_zero(endpoint->resource));

 ao2_lock(endpoint);
 endpoint->state = state;
 ao2_unlock(endpoint);
 endpoint_publish_snapshot(endpoint);
}

void ast_endpoint_set_max_channels(struct ast_endpoint *endpoint,
 int max_channels)
{
 ast_assert(endpoint != NULL);
 ast_assert(!ast_strlen_zero(endpoint->resource));

 ao2_lock(endpoint);
 endpoint->max_channels = max_channels;
 ao2_unlock(endpoint);
 endpoint_publish_snapshot(endpoint);
}

static void endpoint_snapshot_dtor(void *obj)
{
 struct ast_endpoint_snapshot *snapshot = obj;
 int channel;

 ast_assert(snapshot != NULL);

 for (channel = 0; channel < snapshot->num_channels; channel++) {
 ao2_ref(snapshot->channel_ids[channel], -1);
 }

 ast_string_field_free_memory(snapshot);
}

struct ast_endpoint_snapshot *ast_endpoint_snapshot_create(
 struct ast_endpoint *endpoint)
{
 struct ast_endpoint_snapshot *snapshot;
 int channel_count;
 struct ao2_iterator i;
 void *obj;
 SCOPED_AO2LOCK(lock, endpoint);

 ast_assert(endpoint != NULL);
 ast_assert(!ast_strlen_zero(endpoint->resource));

 channel_count = ao2_container_count(endpoint->channel_ids);

 snapshot = ao2_alloc_options(
 sizeof(*snapshot) + channel_count * sizeof(char *),
 endpoint_snapshot_dtor,
 AO2_ALLOC_OPT_LOCK_NOLOCK);

 if (!snapshot || ast_string_field_init(snapshot, 80) != 0) {
 ao2_cleanup(snapshot);
 return NULL;
 }

 ast_string_field_build(snapshot, id, "%s/%s", endpoint->tech,
 endpoint->resource);
 ast_string_field_set(snapshot, tech, endpoint->tech);
 ast_string_field_set(snapshot, resource, endpoint->resource);

 snapshot->state = endpoint->state;
 snapshot->max_channels = endpoint->max_channels;

 i = ao2_iterator_init(endpoint->channel_ids, 0);
 while ((obj = ao2_iterator_next(&i))) {
 /* The reference is kept so the channel id does not go away until the snapshot is gone */
 snapshot->channel_ids[snapshot->num_channels++] = obj;
 }
 ao2_iterator_destroy(&i);

 return snapshot;
}

static void endpoint_cleanup(void)
{
 ao2_cleanup(endpoints);
 endpoints = NULL;

 ao2_cleanup(tech_endpoints);
 tech_endpoints = NULL;
}

int ast_endpoint_init(void)
{
 ast_register_cleanup(endpoint_cleanup);

 endpoints = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0, ENDPOINT_BUCKETS,
 ast_endpoint_hash_fn, NULL, ast_endpoint_cmp_fn);
 if (!endpoints) {
 return -1;
 }

 tech_endpoints = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
 TECH_ENDPOINT_BUCKETS, ast_endpoint_hash_fn, NULL, ast_endpoint_cmp_fn);
 if (!tech_endpoints) {
 return -1;
 }

 return 0;
}